cellulose actividad enzimatica: Topics by WorldWideScience.org [PDF]

Toggle navigation Topics by WorldWideScience.org Home About News Advanced Search Contact Us Site Map Help Sample records for cellulose actividad enzimatica « 1 2 3 4 5 » 1. Enzymatic activity of the cellulolytic complex produced by Trichoderma reesei. Enzymatic hydrolysis of cellulose; Actividad enzimatica del complejo celulolitico producido por Trichoderma reesei. Hidrolisis enzimatica de la celulosa Energy Technology Data Exchange (ETDEWEB) Alfonsel, M.; Negro, M. J.; Saez, R.; Martin, C. 1986-07-01 The enzymatic activity characterization of the cellulolytic complex obtained from Trichoderma reesei QM 9414 and the influence of the enzymatic hydrolysis conditions on the hydrolysis yield are studied. Pure cellulose and native or alkali pretreated biomass Onopordum nervosum have been used as substrates. The values of pH, temperature, substrate concentration and enzyme-substrate ratio for the optimum activity of that complex, evaluated as glucose and reducing sugars production, have been selected. Previous studies on enzymatic hydrolysis of 0. nervosum have shown a remarkable effect of the alkaline pretreatments on the final hydrolysis yield. (Author) 10 refs. 2. Pretreatment of sugarcane bagasse using the advanced oxidation process by electron beam for enzymatic hydrolysis of cellulose; Pre-tratamento do bagaco de cana utilizando o processo de oxidacao avancada por feixe de eletrons para hidrolise enzimatica da celulose Energy Technology Data Exchange (ETDEWEB) Ribeiro, Marcia Almeida 2013-07-01 The sugar cane bagasse is a renewable energy source and a raw material promise in the biofuel production, once represents about 30% of glucose contained in the plant with the potential to be hydrolyzed and then converted to ethanol. The bagasse is composed of cellulose, straight chain of glucose, of hemicellulose, an amorphous polymer consisting of xylose, arabinose, galactose, and mannose, and of lignin, a complex polymer consisting of fenilpropan units that acts as waterproof coating on the fibers, which is hard to remove due its recalcitrant nature. The aim of this work was to study the electron beam processing as a pretreatment of sugarcane bagasse to enzymatic hydrolysis of cellulose. The pretreatment of sugarcane bagasse is one of the most important steps to make this material economically viable and competitive on the energy production. As a pretreatment the electron beam processing can weak the hemicellulose and lignin structures by the action highly reactive radicals that breaks the links, reducing the degree of polymerization fibers. It was evaluated the chemical and structural modifications on fibers caused by the irradiation, the enzymatic hydrolysis of electron beam as the only pretreatment and combined to steam explosion. For enzymatic hydrolysis it was used the commercial enzymes from Novozymes. The radiation processing promotes changes in structure and composition of sugarcane bagasse, increasing the solubility, that is related to hemicellulose and cellulose cleavage, and also increasing the enzymatic conversion yield. In the case of exploded bagasse there is no changes in the enzymatic hydrolysis yield, however the electron beam processing promoted a 67% reduction of furfural, that is formed in the steam explosion process. (author) 3. Hidrolisis enzimatica del acido pectico con una endopoligalacturonasa de levadura: Cinetica y distribucion de masas moleculares National Research Council Canada - National Science Library Serrat-Diaz, Manuel; Dume-Arias, Richard A; Del-Todo-Martinez, Yuniesky; Rodriguez-Gamez, Odalys; Almenares-Verdecia, Juan F; Machado-Garcia, Roberto G 2013-01-01 .... En este trabajo se presenta la cinetica de la hidrolisis enzimatica del acido pectico con una endopoligalacturonasa de levadura, asi como la caracterizacion de la distribucion de masas moleculares en el hidrolizado... 4. Enzymatic hydrolysis of cellulose: Study of the process of recovery of cellulose glucides by the technique of hyperfiltration on polysulphonic membranes. Idrolisi enzimatica della cellulosa. Studio del processo di recupero dei glucidi da cellulasi con tecniche di ultrafiltrazione su membrane polisolfoniche Energy Technology Data Exchange (ETDEWEB) Pizzichini, M.; Fabiani, C.; Sperandei, M. 1986-07-01 Membrane separation technology can optimize some steps of cellulose enzymatic hydrolysis process. In order to continuously remove glucose and cellobiose in the permeate solution and recover the enzymes in the recycling stream, the separation by ultrafiltration of glucides from enzymes was studied. Celluclast enzyme supplied by Novo,in aqueous buffer solution at pH5 and concentration of 0.2-4% w/v range, was used as a feed. Glucides concentration was in the 0.02-0,95% w/v$range. A DDS UF System (Lab Unit-20) was employed with 16 flat membranes type GS81PP with cut off at 6000 dalton. During the separation test, a reduction in the permeate flux caused by protein deposition on the membrane surface was observed. Water washing of the membranes cleans all the membranes package and the original membranes permeability (80 1/sq. m/h at 4 bars) is recovered. Glucides can be quantitatively recovered by the UF process. However the high cellulase concentration may produce a slight enzyme inactivation (2-9%). 5. EFECTO DEL COBRE Y HIERRO SOBRE LA EXPRESION Y ACTIVIDAD ENZIMATICA DE LAS OXIDASAS MULTICOBRE DEL HONGO BASIDIOMICETE PHANEROCHAETE CHRYSOSPORIUM. OpenAIRE CANESSA AGUILA, PAULO FRANCISCO 2009-01-01 Los basidiomicetes como Phanerochaete chrysosporium son un grupo de hongos filamentosos capaces de degradar la lignina, un biopolimero de estructura y composición altamente compleja, presente en la pared celular de las plantas leñosas. Durante la degradac 125p. 6. Ethanol from lignocellulosic biomasses; Etanolo da biomasse lignocellulosiche. Produzione di etanolo da paglia di grano mediante pretrattamento di steam explosion, idrolisi enzimatica e fermentazione Energy Technology Data Exchange (ETDEWEB) Ricci, E.; Viola, E.; Zimbardi, F.; Braccio, G. [ENEA, Divisione Fonti Rinnovabili di Energia, Centro Ricerche Trisaia, Policoro, Matera (Italy); Cuna, D. [Faucitano Srl, Milan (Italy) 2001-07-01 In this report are presented results achieved on the process optimisation of bioethanol production from wheat straw, carried out within the ENEA's project of biomass exploitation for renewable energy. The process consists of three main steps: 1) biomass pretreatment by means of steam explosion; 2) enzymatic hydrolysis of the cellulose fraction; 3) fermentation of glucose. To perform the hydrolysis step, two commercial enzymatic mixtures have been employed, mainly composed by {beta}-glucosidase (cellobiase), endo-glucanase and exoglucanase. The ethanologenic yeast Saccharomyces cerevisiae has been used to ferment the glucose in he hydrolyzates. Hydrolysis yield of 97% has been obtained with steam exploded wheat straw treated at 220{sup 0}C for 3 minutes and an enzyme to substrate ratio of 4%. It has been pointed out the necessity of washing with water the pretreated what straw, in order to remove the biomass degradation products, which have shown an inhibition effect on the yeast. At the best process conditions, a fermentation yield of 95% has been achieved. In the Simultaneous Saccharification and Fermentation process, a global conversion of 92% has been obtained, which corresponds to the production of about 170 grams of ethanol per kilogram of exploded straw. [Italian] Si riportano i risultati di un'attivita' di ricerca finalizzata all'ottimizzazione del processo di produzione di etanolo da paglia di grano. Il processo esaminato consta di un pretrattamento mediante steam explosion della paglia, seguito da idrolisi enzimatica della cellulosa e fermentazione del glucosio ottenuto. Per effettuare l'idrolisi sono stati utilizzati due preparati enzimatici disponibili commercialmente, costituiti da {beta}-glucosidasi, endo-glucanasi ed eso-glucanasi. Per la fermentazione del glucosio negli idrolizzati e' stato impiegato il lievito Saccharomyces cerevisae. E' stata raggiunta un'efficienza massima di idrolisi del 97% utilizzando 7. Hidrolisis enzimatica del acido pectico con una endopoligalacturonasa de levadura: Cinetica y distribucion de masas moleculares National Research Council Canada - National Science Library Serrat-Diaz, Manuel; Dume-Arias, Richard A; Del-Todo-Martinez, Yuniesky; Rodriguez-Gamez, Odalys; Almenares-Verdecia, Juan F; Machado-Garcia, Roberto G 2013-01-01 Los oligogalacturonidos se erigen como prometedoras biomoleculas para uso agricola, en la biotecnologia vegetal y en la elaboracion de alimentos funcionales, debido a su potente y diversa actividad... 8. Promiscuità enzimatica ed evoluzione molecolare:studio di una lattonasi da Sulfolobus solfataricus in grado di degradare agenti nervini OpenAIRE Merone, Luigia 2010-01-01 Si definisce promiscuità catalitica la capacità di un enzima di catalizzare reazioni aggiuntive al ruolo principale, che possono essere più o meno chimicamente differenti tra loro. Questa definizione si riferisce sia alla possibilità di catalizzare la trasformazione di substrati di natura diversa che di utilizzare differenti meccanismi di reazione e/o diversi siti catalitici1,2. L'enorme importanza legata allo studio della promiscuità enzimatica è sostanzialmente duplice. Da un punto di vista... 9. Memoria de Actividad 2012 OpenAIRE CSIC - Instituto de Productos Lácteos de Asturias (IPLA) 2012-01-01 Memoria de actividad del eLearn Center, el centro de investigación, formación e innovación en e-learning de la UOC, correspondiente al año 2012. Memòria d'activitat de l'eLearn Center, el centre de recerca, formació i innovació en e-learning de la UOC, corresponent a l'any 2012. 2012 Report on activities of the eLearn Center, the e-learning research, innovation and training centre of the UOC. 10. Memoria de Actividad 2013 OpenAIRE CSIC - Instituto de Productos Lácteos de Asturias (IPLA) 2013-01-01 Memoria de actividad del eLearn Center, el centro de investigación, formación e innovación en e-learning de la UOC, correspondiente al año 2013. Memòria d'activitat de l'eLearn Center, el centre de recerca, formació i innovació en e-learning de la UOC, corresponent a l'any 2013. 2013 Report on activities of the eLearn Center, the e-learning research, innovation and training centre of the UOC. 11. Propostas de actividades Directory of Open Access Journals (Sweden) PROJECTO, "Criança, sujeito de direitos: a infância que se ergue" 2010-10-01 Full Text Available O conjunto de actividades que apresentamos tem a sua origem no trabalho desenvolvido pelos diversos professores/as juntamente com as crianças com as quais partilharam o projecto “Criança, sujeito de direitos: a infância que se ergueâ€. Sendo assim, são propostas já desenvolvidas e experimentadas com sucesso. Enfatizamos que qualquer actividade pedagógica deve ser cautelosamente analisada para poder servir como ponto de partida, sendo redimensionada de acordo com cada grupo de crianças, contextualizada para atender aos nÃveis e padrões de interesse e objectivos que se pretendam atingir. Evidentemente que devem ser adaptadas criteriosamente e sempre no sentido de melhor desenvolver o trabalho, enriquecendo-o, acrescentando, inovando, mas sobretudo sem perder de vista o caminho da reflexão e avaliação acerca do que têm sido os resultados. 12. Cellulose is not just cellulose DEFF Research Database (Denmark) Hidayat, Budi Juliman; Felby, Claus; Johansen, Katja Salomon 2012-01-01 or enzymatic hydrolysis of plant cell walls is carried out simultaneously with the application of shear stress, plant cells such as fibers or tracheids break at their dislocations. At present it is not known whether specific carbohydrate binding modules (CBMs) and/or cellulases preferentially access cellulose......Most secondary plant cell walls contain irregular regions known as dislocations or slip planes. Under industrial biorefining conditions dislocations have recently been shown to play a key role during the initial phase of the enzymatic hydrolysis of cellulose in plant cell walls. In this review we...... are not regions where free cellulose ends are more abundant than in the bulk cell wall. In more severe cases cracks between fibrils form at dislocations and it is possible that the increased accessibility that these cracks give is the reason why hydrolysis of cellulose starts at these locations. If acid... 13. Costos basados en la actividad OpenAIRE Delicio, Fabián A. 1998-01-01 La metodologÃa de Costos Basados en la Actividad (ABC) significa un importante cambio en la asignación de los costos de los productos. Su originalidad parte de relacionar la base de asignación para los costos indirectos con las actividades desarrolladas en cada uno de los departamentos o centros de costos. Introduce el concepto de Inductor de Costos, para la asignación de los costos, para la asignación de los costos y gastos fijos, que está determinado por las actividades que se realizan en e... 14. Actividad antimicrobiana de Oedogonium capillare OpenAIRE Rosa Martha Pérez Gutiérrez 2007-01-01 se evaluó la actividad antimicrobiana de los extractos hexánico, clorofórmico y metanólico de las hojas de Oedogonium capillare sobre 8 microorganismos (Staphylococcus aureus, Staphylococcus epidermidis, Bacillus subtilis, Bacillus cereus, Escherichia coli, Vibrio cholerae, Salmonella typhi y Klebsiella pneumoniae). El extracto hexánico presentó un amplio espectro antibacteriano y fue más activo que los extractos de cloroformo y metanol, su actividad se comparó con la producida por la gentami... 15. Cellulose Insulation Science.gov (United States) 1980-01-01 Fire retardant cellulose insulation is produced by shredding old newspapers and treating them with a combination of chemicals. Insulating material is blown into walls and attics to form a fiber layer which blocks the flow of air. All-Weather Insulation's founders asked NASA/UK-TAP to help. They wanted to know what chemicals added to newspaper would produce an insulating material capable of meeting federal specifications. TAP researched the query and furnished extensive information. The information contributed to successful development of the product and helped launch a small business enterprise which is now growing rapidly. 16. Cellulose metabolism in plants. Science.gov (United States) Hayashi, Takahisa; Yoshida, Kouki; Park, Yong Woo; Konishi, Teruko; Baba, Kei'ichi 2005-01-01 Many bacterial genomes contain a cellulose synthase operon together with a cellulase gene, indicating that cellulase is required for cellulose biosynthesis. In higher plants, there is evidence that cell growth is enhanced by the overexpression of cellulase and prevented by its suppression. Cellulase overexpression could modify cell walls not only by trimming off the paracrystalline sites of cellulose microfibrils, but also by releasing xyloglucan tethers between the microfibrils. Mutants for membrane-anchored cellulase (Korrigan) also show a typical phenotype of prevention of cellulose biosynthesis in tissues. All plant cellulases belong to family 9, which endohydrolyzes cellulose, but are not strong enough to cause the bulk degradation of cellulose microfibrils in a plant body. It is hypothesized that cellulase participates primarily in repairing or arranging cellulose microfibrils during cellulose biosynthesis in plants. A scheme for the roles of plant cellulose and cellulases is proposed. 17. Electrically conductive cellulose composite Science.gov (United States) Evans, Barbara R.; O'Neill, Hugh M.; Woodward, Jonathan 2010-05-04 An electrically conductive cellulose composite includes a cellulose matrix and an electrically conductive carbonaceous material incorporated into the cellulose matrix. The electrical conductivity of the cellulose composite is at least 10 .mu.S/cm at 25.degree. C. The composite can be made by incorporating the electrically conductive carbonaceous material into a culture medium with a cellulose-producing organism, such as Gluconoacetobacter hansenii. The composites can be used to form electrodes, such as for use in membrane electrode assemblies for fuel cells. 18. Efectos del entorno de actividad nuclear OpenAIRE Sabater, J.; Verdes-Montenegro, L.; Leon, S.; Sulentic, J.; Lisenfeld, Ute; Verley, S. 2010-01-01 Presentamos un estudio de la relaci??n entre los efectos del entorno y el fen??meno de la actividad nuclear en general y la actividad nuclear de tipo radio (presencia de un chorro) en particular, en una muestra de galaxias aisladas. 19. Actividad fÃsica responsable OpenAIRE Bertsch, Adolfo Marcelo; Smario, Lis 2009-01-01 El objetivo de este trabajo es tratar la responsabilidad de quienes guÃan la práctica deportiva. En los últimos años se ha dado un fenómeno por el cual, la actividad fÃsica dejo de ser solo para aquellos que se dedicaban a la practica deportiva para competición, y mas personas, que antes no realizaban actividad, se volcaron a la misma, con fines de salud o estéticos, es decir, la actividad deportiva dejo de ser una patrimonio solo de atletas, para convertirse en una practica común. Asà ... 20. Cellulose Degradation by Cellulose-Clearing and Non-Cellulose-Clearing Brown-Rot Fungi OpenAIRE Highley, Terry L. 1980-01-01 Cellulose degradation by four cellulose-clearing brown-rot fungi in the Coniophoraceae—Coniophora prasinoides, C. puteana, Leucogyrophana arizonica, and L. olivascens—is

compared with that of a non-cellulose-clearing brown-rot fungus, Poria placenta. The cellulose- and the non-cellulose-clearing brown-rot fungi apparently employ similar mechanisms to depolymerize cellulose; most likely a nonenzymatic mechanism is involved. « 1 2 3 4 5 » « 1 2 3 4 5 » 21. Cellulose binding domain proteins Science.gov (United States) Shoseyov, Oded; Shpiegl, Itai; Goldstein, Marc; Doi, Roy 1998-01-01 A cellulose binding domain (CBD) having a high affinity for crystalline cellulose and chitin is disclosed, along with methods for the molecular cloning and recombinant production thereof. Fusion products comprising the CBD and a second protein are likewise described. A wide range of applications are contemplated for both the CBD and the fusion products, including drug delivery, affinity separations, and diagnostic techniques. 22. Actividad sociocognitiva y contextos postfordistas Directory of Open Access Journals (Sweden) Quintana Castelló, Francisco 2009-08-01 Full Text Available In contemporary capitalism, productive economical activity changes into configuring a hybrid landscape formed by a mixture of advanced modalities based on microelectronics and language, which are postfordist, and techno-organizational and contractual components evoking, some of them, the manchesterian “factory systemâ€. These changes involve a deep transformation of work and technic systems and organizations distinctly differents from those which appear defined by “endogenous†thesis (Smith’s version and Kaldor law. In new prototypes, turning to automatic and telecommunication systems as well as to a relational, cognitive and linguistic productive forms, knowledge raises as capital productive force. Nevertheless, most of all, this knowledge is fed by an innovative environment and a systemic and not systemic knowledge. However, these changes involve the emergence of new problems, being to emphasize the dychotomic character of those processes which generate valuating knowledge in a global context determined by asset logic. En el capitalismo contemporáneo la actividad económica productiva se metamorfosea para configurar un paisaje hÃbrido, mezcla de modalidades avanzadas basadas en la microelectrónica y el lenguaje, postfordistas, y componentes tecno-organizativos y contractuales, algunos de los cuales evocan el factory system manchesteriano. Estos cambios comportan una profunda transformación del trabajo y de los sistemas técnicos y organizativos, perfectamente diferenciados de los que aparecen definidos por las tesis â €œendógenas†(versión smithiana y ley de Kaldor. En los nuevos prototipos, que recurren a sistemas automáticos y telemáticos y a formas de productivas relacionales, cognitivas y lingüÃsticas, el conocimiento se erige en fuerza productiva de primer orden. Un conocimiento, sin embargo, que se nutre sobre todo de un entorno innovador y del saber social sistémico y no sistémico. No obstante, esto 23. Hazy Transparent Cellulose Nanopaper Science.gov (United States) Hsieh, Ming-Chun; Koga, Hirotaka; Suganuma, Katsuaki; Nogi, Masaya 2017-01-01 The aim of this study is to clarify light scattering mechanism of hazy transparent cellulose nanopaper. Clear optical transparent nanopaper consists of 3–15 nm wide cellulose nanofibers, which are obtained by the full nanofibrillation of pulp fibers. At the clear transparent nanopaper with 40 μm thickness, their total transmittance are 89.3–91.5% and haze values are 4.9–11.7%. When the pulp fibers are subjected to weak nanofibrillation, hazy transparent nanopapers are obtained. The hazy transparent nanopaper consists of cellulose nanofibers and some microsized cellulose fibers. At the hazy transparent nanopaper with 40 μm thickness, their total transmittance were constant at 88.6–92.1% but their haze value were 27.3–86.7%. Cellulose nanofibers are solid cylinders, whereas the pulp fibers are hollow cylinders. The hollow shape is retained in the microsized cellulose fibers, but they are compressed flat inside the nanopaper. This compressed cavity causes light scattering by the refractive index difference between air and cellulose. As a result, the nanopaper shows a hazy transparent appearance and exhibits a high thermal durability (295–305 °C), and low thermal expansion (8.5–10.6 ppm/K) because of their high density (1.29–1.55 g/cm3) and crystallinity (73–80%). 24. Fulton Cellulosic Ethanol Biorefinery Energy Technology Data Exchange (ETDEWEB) Sumait, Necy [BlueFire Ethanol, Irvine, CA (United States); Cuzens, John [BlueFire Ethanol, Irvine, CA (United States); Klann, Richard [BlueFire Ethanol, Irvine, CA (United States) 2015-07-24 Final report on work performed by BlueFire on the deployment of acid hydrolysis technology to convert cellulosic waste materials into renewable fuels, power and chemicals in a production facility to be located in Fulton, Mississippi. 25. Photoresponsive Cellulose Nanocrystals Directory of Open Access Journals (Sweden) Dimitris S Argyropoulos 2011-07-01 Full Text Available In this communication a method for the creation of fluorescent cellulose nanoparticles using click chemistry and subsequent photodimerization of the installed side†chains is demonstrated. In the first step, the primary hydroxyl groups on the surface of the CNCs were converted to carboxylic acids by using TEMPOâ€mediated hypohalite oxidation. The alkyne groups, essential for the click reaction, were introduced into the surface of TEMPO†oxidized CNCs via carbodiimideâ€mediated formation of an amide linkage between monomers carrying an amine functionality and carboxylic acid groups on the surface of the TEMPOâ€oxidized CNCs. Finally, the reaction of surfaceâ€modified TEMPOâ€oxidized cellulose nanocrystals and azidoâ€bearing coumarin and anthracene monomers were carried out by means of a click chemistry, i.e., Copper(Iâ€catalyzed Azideâ €Alkyne Cycloaddition (CuAAC to produce highly photoâ€responsive and fluorescent cellulose nanoparticles. Most significantly, the installed coumarin and/or anthracene sideâ €chains were shown to undergo UVâ€induced [2+2] and [4+4] cycloaddition reactions, bringing and locking the cellulose nanocrystals together. This effort paves the way towards creating, cellulosic photo responsive nanoâ€arrays with the potential of photo reversibility since these reactions are known to be reversible at varying wavelengths. 26. Inhibidores de la histidina quinasa con actividad antibacteriana OpenAIRE Marina, Alberto; Velikova, Nadya; Finn, Paul; Fulle, Simone; Wells, Jerry M. 2014-01-01 Inhibidores de la histidina guinasa con actividad antibacteriana. La presente invención se refiere a un grupo de compuestos con actividad inhibidora de la autofosforilación y actividad antibacteriana frente a diferentes bacterias como Staphylococcus aureus y Staphylococcus epidermidis entre otras, y al uso de dichos compuestos para la fabricación de antibióticos. 27. Actividad fisica en empleados de la Universidad de Caldas, Colombia National Research Council Canada - National Science Library Pena Quimbaya, Eder; Colina Gallo, Evelyn; Vasquez Gomez, Ana Cecilia 2009-01-01 ...; la actividad fisica esta intimamente relacionada con el termino ejercicio fisico que es un tipo de actividad fisica planeada, estructurada y repetitiva con el objetivo de mejorar o mantener uno o mas componentes de la condicion fisica, la cual es una serie de atributos que la gente tiene o alcanza como resultado de la habilidad para realizar actividad fi... 28. Cellulosic fibril–rubber nanocomposites CSIR Research Space (South Africa) Jacob John, Maya 2010-06-01 Full Text Available Cellulose is the most abundant polymer on earth- has emerged as an ideal candidate for providing nanoparticles as reinforcing agents. There is a growing interest in cellulose nanocomposites within the research community and especially... 29. Acid hydrolysis of cellulose Energy Technology Data Exchange (ETDEWEB) Salazar, H. 1980-12-01 One of the alternatives to increase world production of etha nol is by the hydrolysis of cellulose content of agricultural residues. Studies have been made on the types of hydrolysis: enzimatic and acid. Data obtained from the sulphuric acid hydrolysis of cellulose showed that this process proceed in two steps, with a yield of approximately 95% glucose. Because of increases in cost of alternatives resources, the high demand of the product and the more economic production of ethanol from cellulose materials, it is certain that this technology will be implemented in the future. At the same time further studies on the disposal and reuse of the by-products of this production must be undertaken. 30. The cellulose resource matrix. Science.gov (United States) Keijsers, Edwin R P; Yılmaz, Gülden; van Dam, Jan E G 2013-03-01 The emerging biobased economy is causing shifts from mineral fossil oil based resources towards renewable resources. Because of market mechanisms, current and new industries utilising renewable commodities, will attempt to secure their supply of resources. Cellulose is among these commodities, where large scale competition can be expected and already is observed for the traditional industries such as the paper industry. Cellulose and lignocellulosic raw materials (like wood and non-wood fibre crops) are being utilised in many industrial sectors. Due to the initiated transition towards biobased economy, these raw materials are intensively investigated also for new applications such as 2nd generation biofuels and 'green' chemicals and materials production (Clark, 2007; Lange, 2007; Petrus & Noordermeer, 2006; Ragauskas et al., 2006; Regalbuto, 2009). As lignocellulosic raw materials are available in variable quantities and qualities, unnecessary competition can be avoided via the choice of suitable raw materials for a target application. For example, utilisation of cellulose as carbohydrate source for ethanol production (Kabir Kazi et al., 2010) avoids the discussed competition with easier digestible carbohydrates (sugars, starch) deprived from the food supply chain. Also for cellulose use as a biopolymer several different competing markets can be distinguished. It is clear that these applications and markets will be influenced by large volume shifts. The world will have to reckon with the increase of competition and feedstock shortage (land use/biodiversity) (van Dam, de Klerk-Engels, Struik, & Rabbinge, 2005). It is of interest - in the context of sustainable development of the bioeconomy - to categorize the already available and emerging lignocellulosic resources in a matrix structure. When composing such "cellulose resource matrix" attention should be given to the quality aspects as well as to the available quantities and practical possibilities of processing the 31. Cellulose Microfibril Formation by Surface-Tethered Cellulose Synthase Enzymes. Science.gov (United States) Basu, Snehasish; Omadjela, Okako; Gaddes, David; Tadigadapa, Srinivas; Zimmer, Jochen; Catchmark, Jeffrey M 2016-02-23 Cellulose microfibrils are pseudocrystalline arrays of cellulose chains that are synthesized by cellulose synthases. The enzymes are organized into large membrane-embedded complexes in which each enzyme likely synthesizes and secretes a β-(1→4) glucan. The relationship between the organization of the enzymes in these complexes and cellulose crystallization has not been explored. To better understand this relationship, we used atomic force microscopy to visualize cellulose microfibril formation from nickel-filmimmobilized bacterial cellulose synthase enzymes (BcsA-Bs), which in standard solution only form amorphous cellulose from monomeric BcsA-B complexes. Fourier transform infrared spectroscopy and X-ray diffraction techniques show that surface-tethered BcsA-Bs synthesize highly crystalline cellulose II in the presence of UDP-Glc, the allosteric activator cyclic-di-GMP, as well as magnesium. The cellulose II cross section/diameter and the crystal size and crystallinity depend on the surface density of tethered enzymes as well as the overall concentration of substrates. Our results provide the correlation between cellulose microfibril formation and the spatial organization of cellulose synthases. 32. CHARACTERIZATION OF REGENERATED CELLULOSE MEMBRANES HYDROLYZED FROM CELLULOSE ACETATE Institute of Scientific and Technical Information of China (English) Yun Chen; Xiao-peng Xiong; Guang Yang; Li-na Zhang; Sen-lin Lei; Hui Lianga 2002-01-01 A series of cellulose acetate membranes were prepared by using formamide as additive, and then were hydrolyzedin 4 wt% aqueous NaOH solution for 8 h to obtain regenerated cellulose membranes. The dependence of degree ofsubstitution, structure, porous properties, solubility and thermal stability on hydrolysis time was studied by chemical titration,Fourier transform infrared spectroscopy, scanning electron microscopy, wide-angle X-ray diffraction, and differentialscanning calorimetry, respectively. The results indicated that the pore size of the regenerated cellulose membranes wasslightly smaller than that of cellulose acetate membrane, while solvent-resistance, crystallinity and thermostability weresignificantly improved. This work provides a simple way to prepare the porous cellulose membranes, which not only kept thegood pore characteristics of cellulose acetate membranes, but also possessed solvent-resistance, high crystallinity andthermostability. Therefore, the application range of cellulose acetate membranes can be expanded. 33. Actividad Antimicrobiana de Cuminum cyminum L. OpenAIRE M.; De, A K; Mukhopadhyay, R.; Banerjee, A.B.; M. Mir 2003-01-01 El comino (Cuminum cyminum) es un ingrediente habitual en la comida india. Ha sido usado desde hace mucho tiempo en la medicina tradicional para curar la diarrea, dispepsia y trastornos g??stricos, as?? como agente antis??ptico. Estudios realizados en nuestro laboratorio han mostrado que el comino tiene una potente actividad antimicrobiana sobre diversas especies de bacterias y hongos, tanto pat??genas como no pat??genas. Los estudios qu??micos realizados indican que la mayor part... 34. actividades con imágenes Directory of Open Access Journals (Sweden) Asunción López-Manjón 2016-01-01 Full Text Available El objetivo de este artÃculo es aportar criterios para ayudar a la selección de libros de texto poniendo el foco en el análisis de la competencia gráfica o visual fomentada en sus actividades. Los criterios son puestos a prueba a través de la comparación de libros de Primaria de diferentes editoriales españolas, analizando cómo se trabaja la competencia visual en las actividades de las unidades didácticas sobre el cuerpo humano. Algunos de los criterios estudiados son: tipo de tarea, procedimientos implicados, nivel de procesamiento cognitivo y pautas de enseñanza para trabajar la imagen. Una de las editoriales destaca frente a las demás por ser la que mejor promueve la alfabetización gráfica en las actividades sobre el cuerpo humano y también se analizan las distintas contribuciones de las otras editoriales. Aunque los criterios propuestos ayudan a la selección del libro de texto más adecuado desde el punto de vista de la competencia gráfica, también ponen de manifiesto la necesidad de cambiar la concepción y uso de las imágenes como herramienta de aprendizaje. 35. The cellulose resource matrix NARCIS (Netherlands) Keijsers, E.R.P.; Yilmaz, G.; Dam, van J.E.G. 2013-01-01 The emerging biobased economy is causing shifts from mineral fossil oil based resources towards renewable resources. Because of market mechanisms, current and new industries utilising renewable commodities, will attempt to secure their supply of resources. Cellulose is among these commodities, where 36. Calculating cellulose diffraction patterns Science.gov (United States) Although powder diffraction of cellulose is a common experiment, the patterns are not widely understood. The theory is mathematical, there are numerous different crystal forms, and the conventions are not standardized. Experience with IR spectroscopy is not directly transferable. An awful error, tha... 37. The cellulose resource matrix NARCIS (Netherlands) Keijsers, E.R.P.; Yilmaz, G.; Dam, van J.E.G. 2013-01-01 The emerging biobased economy is causing shifts from mineral fossil oil based resources towards renewable resources. Because of market mechanisms, current and new industries utilising renewable commodities, will attempt to secure their supply of resources. Cellulose is among these commodities, where 38. Actividad real y actividad ideal (§§ 3 y 4) OpenAIRE Jiménez Redondo, Manuel 2012-01-01 El artÃculo es un comentario de los parágrafos §3 y §4 en un intento por comprender los conceptos fichteanos de “actividad real†y “actividad idealâ€. A tal fin se pasa revista a otros conceptos fichteanos como los de “intuición intelectual†o “conciencia inmediataâ€, prestándose asimismo atención a las nociones de “principio de la filosofÃa†y “pensamiento enérgicoâ€. 39. Cellulose Isolation Methodology for NMR Analysis of Cellulose Ultrastructure Directory of Open Access Journals (Sweden) Art J. Ragauskas 2011-11-01 Full Text Available In order to obtain accurate information about the ultrastructure of cellulose from native biomass by 13C cross polarization magic angle spinning (CP/MAS NMR spectroscopy the cellulose component must be isolated due to overlapping resonances from both lignin and hemicellulose. Typically, cellulose isolation has been achieved via holocellulose pulping to remove lignin followed by an acid hydrolysis procedure to remove the hemicellulose components. Using 13C CP/MAS NMR and non-linear line-fitting of the cellulose C4 region, it was observed that the standard acid hydrolysis procedure caused an apparent increase in crystallinity of ~10% or less on the cellulose isolated from Populus holocellulose. We have examined the effect of the cellulose isolation method, particularly the acid treatment time for hemicellulose removal, on cellulose ultrastructural characteristics by studying these effects on cotton, microcrystalline cellulose (MCC and holocellulose pulped Populus. 13C CP/MAS NMR of MCC indicated that holocellulose pulping and acid hydrolysis has little effect on the crystalline ultrastructural components of cellulose. Although any chemical method to isolate cellulose from native biomass will invariably alter substrate characteristics, especially those related to regions accessible to solvents, we found those changes to be minimal and consistent in samples of typical crystallinity and lignin/hemicellulose content. Based on the rate of the hemicellulose removal, as determined by HPLC-carbohydrate analysis and magnitude of cellulose ultrastructural alteration, the most suitable cellulose isolation methodology utilizes a treatment of 2.5 M HCl at 100 °C for a standard residence time between 1.5 and 4 h. However, for the most accurate crystallinity results this residence time should be determined empirically for a particular sample. 40. Enhanced enzymatic hydrolysis of cellulose in microgels. Science.gov (United States) Chang, Aiping; Wu, Qingshi; Xu, Wenting; Xie, Jianda; Wu, Weitai 2015-07-04

A cellulose-based microgel, where an individual microgel contains approximately one cellulose chain on average, is synthesized via free radical polymerization of a difunctional small-molecule N,N'-methylenebisacrylamide in cellulose solution. This microgelation leads to a low-ordered cellulose, favoring enzymatic hydrolysis of cellulose to generate glucose. « 1 2 3 4 5 » « 1 2 3 4 5 » 41. Cellulose biogenesis in Dictyostelium discoideum Energy Technology Data Exchange (ETDEWEB) Blanton, R.L. 1993-12-31 Organisms that synthesize cellulose can be found amongst the bacteria, protistans, fungi, and animals, but it is in plants that the importance of cellulose in function (as the major structural constituent of plant cell walls) and economic use (as wood and fiber) can be best appreciated. The structure of cellulose and its biosynthesis have been the subjects of intense investigation. One of the most important insights gained from these studies is that the synthesis of cellulose by living organisms involves much more than simply the polymerization of glucose into a (1{r_arrow}4)-{beta}-linked polymer. The number of glucoses in a polymer (the degree of polymerization), the crystalline form assumed by the glucan chains when they crystallize to form a microfibril, and the dimensions and orientation of the microfibrils are all subject to cellular control. Instead of cellulose biosynthesis, a more appropriate term might be cellulose biogenesis, to emphasize the involvement of cellular structures and mechanisms in controlling polymerization and directing crystallization and deposition. Dictyostelium discoideum is uniquely suitable for the study of cellulose biogenesis because of its amenability to experimental study and manipulation and the extent of our knowledge of its basic cellular mechanisms (as will be evident from the rest of this volume). In this chapter, I will summarize what is known about cellulose biogenesis in D. discoideum, emphasizing its potential to illuminate our understanding both of D. discoideum development and plant cellulose biogenesis. 42. Acetoacetylation of Hydroxyethyl Cellulose Institute of Scientific and Technical Information of China (English) 陈晓锋; 高彦芳; æœå¥•; 刘德山 2002-01-01 The acetoacetyl group can be used to improve superabsorbent resins since it is more active than the hydroxyethyl group. The acetoacetyl group can be introduced into the side group of hydroxyethyl cellulose (HEC) to activate HEC using the ester exchange reaction between HEC and ethyl acetoacetate (EAA) to improve HEC grafting. This paper discusses the main factors affecting the reaction, such as the amount of EAA and catalyzer, the reaction temperature, and the reaction time. The acetoacetyl group was successfully introduced into HEC. Within specified ranges, increasing the amount of EAA, the reaction temperature and the reaction time will increase the acetoacetylation. 43. Cellulose binding domain fusion proteins Science.gov (United States) Shoseyov, Oded; Shpiegl, Itai; Goldstein, Marc A.; Doi, Roy H. 1998-01-01 A cellulose binding domain (CBD) having a high affinity for crystalline cellulose and chitin is disclosed, along with methods for the molecular cloning and recombinant production thereof. Fusion products comprising the CBD and a second protein are likewise described. A wide range of applications are contemplated for both the CBD and the fusion products, including drug delivery, affinity separations, and diagnostic techniques. 44. Cellulose Synthesis in Agrobacterium tumefaciens Energy Technology Data Exchange (ETDEWEB) Alan R. White; Ann G. Matthysse 2004-07-31 We have cloned the celC gene and its homologue from E. coli, yhjM, in an expression vector and expressed the both genes in E. coli; we have determined that the YhjM protein is able to complement in vitro cellulose synthesis by extracts of A. tumefaciens celC mutants, we have purified the YhjM protein product and are currently examining its enzymatic activity; we have examined whole cell extracts of CelC and various other cellulose mutants and wild type bacteria for the presence of cellulose oligomers and cellulose; we have examined the ability of extracts of wild type and cellulose mutants including CelC to incorporate UDP-14C-glucose into cellulose and into water-soluble, ethanol-insoluble oligosaccharides; we have made mutants which synthesize greater amounts of cellulose than the wild type; and we have examined the role of cellulose in the formation of biofilms by A. tumefaciens. In addition we have examined the ability of a putative cellulose synthase gene from the tunicate Ciona savignyi to complement an A. tumefaciens celA mutant. The greatest difference between our knowledge of bacterial cellulose synthesis when we started this project and current knowledge is that in 1999 when we wrote the original grant very few bacteria were known to synthesize cellulose and genes involved in this synthesis were sequenced only from Acetobacter species, A. tumefaciens and Rhizobium leguminosarum. Currently many bacteria are known to synthesize cellulose and genes that may be involved have been sequenced from more than 10 species of bacteria. This additional information has raised the possibility of attempting to use genes from one bacterium to complement mutants in another bacterium. This will enable us to examine the question of which genes are responsible for the three dimensional structure of cellulose (since this differs among bacterial species) and also to examine the interactions between the various proteins required for cellulose synthesis. We have carried out one 45. Ultrasonic dyeing of cellulose nanofibers. Science.gov (United States) Khatri, Muzamil; Ahmed, Farooq; Jatoi, Abdul Wahab; Mahar, Rasool Bux; Khatri, Zeeshan; Kim, Ick Soo 2016-07-01 Textile dyeing assisted by ultrasonic energy has attained a greater interest in recent years. We report ultrasonic dyeing of nanofibers for the very first time. We chose cellulose nanofibers and dyed with two reactive dyes, CI reactive black 5 and CI reactive red 195. The cellulose nanofibers were prepared by electrospinning of cellulose acetate (CA) followed by deacetylation. The FTIR results confirmed complete conversion of CA into cellulose nanofibers. Dyeing parameters optimized were dyeing temperature, dyeing time and dye concentrations for each class of the dye used. Results revealed that the ultrasonic dyeing produced higher color yield (K/S values) than the conventional dyeing. The color fastness test results depicted good dye fixation. SEM analysis evidenced that ultrasonic energy during dyeing do not affect surface morphology of nanofibers. The results conclude successful dyeing of cellulose nanofibers using ultrasonic energy with better color yield and color fastness results than conventional dyeing. 46. Approaching zero cellulose loss in cellulose nanocrystal (CNC) production: recovery and characterization of cellulosic solid residues (CSR) and CNC Science.gov (United States) Q.Q. Wang; J.Y. Zhu; R.S. Reiner; S.P. Verrill; U. Baxa; S.E. McNeil 2012-01-01 This study demonstrated the potential of simultaneously recovering cellulosic solid residues (CSR) and producing cellulose nanocrystals (CNCs) by strong sulfuric acid hydrolysis to minimize cellulose loss to near zero. A set of slightly milder acid hydrolysis conditions than that considered as “optimal†were used to significantly minimize the degradation of cellulose... 47. 21 CFR 172.868 - Ethyl cellulose. Science.gov (United States) 2010-04-01 ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Ethyl cellulose. 172.868 Section 172.868 Food and... Multipurpose Additives § 172.868 Ethyl cellulose. The food additive ethyl cellulose may be safely used in food in accordance with the following prescribed conditions: (a) The food additive is a cellulose... 48. 21 CFR 573.420 - Ethyl cellulose. Science.gov (United States) 2010-04-01 ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Ethyl cellulose. 573.420 Section 573.420 Food and... Listing § 573.420 Ethyl cellulose. The food additive ethyl cellulose may be safely used in animal feed in accordance with the following prescribed conditions: (a) The food additive is a cellulose ether... 49. Cellulose Nanomaterials in Water Treatment Technologies OpenAIRE Carpenter, Alexis Wells; de Lannoy, Charles François; Mark R. Wiesner 2015-01-01 Cellulose nanomaterials are naturally occurring with unique structural, mechanical and optical properties. While the paper and packaging, automotive, personal care, construction, and textiles industries have recognized cellulose nanomaterials’ potential, we suggest cellulose nanomaterials have great untapped potential in water treatment technologies. In this review, we gather evidence of cellulose nanomaterials’ beneficial role in environmental remediation and membranes for water filtration, ... 50. Cellulose nanocrystals: synthesis, functional properties, and applications OpenAIRE George J.; Sabapathi SN 2015-01-01 Johnsy George, SN Sabapathi Food Engineering and Packaging Division, Defence Food Research Laboratory, Siddarthanagar, Mysore, Karnataka, India Abstract: Cellulose nanocrystals are unique nanomaterials derived from the most abundant and almost inexhaustible natural polymer, cellulose. These nanomaterials have received significant interest due to their mechanical, optical, chemical, and rheological properties. Cellulose nanocrystals primarily obtained from naturally occurring cellulose fibers... 51. Methane fermentation of cellulose and ligno-cellulosic materials Energy Technology Data Exchange (ETDEWEB) Bachman, J.S.; Villermaux, S.; Prost, C. (Laboratoire des Sciences du Genie Chimique, 54 - Nancy (France)) 1985-01-01 Study of the methane fermentation of two simple substrates i.e. pure cellulose and oat straw. Experiments have been carried out in laboratory fermentors with several initial cellulose concentrations and different straw particle sizes. The results show the effect of adding nutrients and enriched seedings with pure cellulolytic or methanogenic bacteria. In each case, the rate limiting step is defined and the degradation kinetics of the two substrates are compared. 52. Escaparate Interactivo de Actividades TurÃsticas OpenAIRE Nieto Muñoz, Diego 2013-01-01 [ES]En este proyecto se ha pretendido desarrollar un completo sistema de gestión de actividades turÃsticas. Para ello se ha investigado cómo los hoteles y las empresas interactúan con los turistas y les muestran su oferta de ocio. Como resultado de esa investigación se propone un sistema de recomendación de actividades a los turistas. Este sistema contiene las actividades de la empresa de ocio y hoteles que se registran. La aplicación ha sido diseñada de forma que los usuarios de los diferent... 53. WOOD CELLULOSE ACETATE MEMBRANE 179 African Journals Online (AJOL) DR. AMINU 2013-06-01 Jun 1, 2013 ... process. The harnessed cellulose was acetylated by the process of step-wise acetylation to a degree of acetylation (DA) of ... several fields including oil recovery (Heinrich and ..... removed by filtration using the membrane was. 54. Bacterial cellulose/boehmite composites Energy Technology Data Exchange (ETDEWEB) Salvi, Denise T.B. de; Barud, Hernane S.; Messaddeq, Younes; Ribeiro, Sidney J.L. [Universidade Estadual Paulista Julio de Mesquita Filho. UNESP. Instituto de Quimica de Araraquara, SP (Brazil); Caiut, Jose Mauricio A. [Universidade de Sao Paulo. Departamento de Quimica - FFCLRP/USP, Ribeirao Preto, SP (Brazil) 2011-07-01 Composites based on bacterial cellulose membranes and boehmite were obtained. SEM results indicate that the bacterial cellulose (BC) membranes are totally covered by boehmite and obtained XRD patterns suggest structural changes due to this boehmite addition. Thermal stability is accessed through TG curves and is dependent on boehmite content. Transparency is high comparing to pure BC as can be seen through UV-vis absorption spectroscopy. (author) 55. Surface modification of cellulose nanocrystals Science.gov (United States) Eyley, Samuel; Thielemans, Wim 2014-06-01 Chemical modification of cellulose nanocrystals is an increasingly popular topic in the literature. This review analyses the type of cellulose nanocrystal modification reactions that have been published in the literature thus far and looks at the steps that have been taken towards analysing the products of the nanocrystal modifications. The main categories of reactions carried out on cellulose nanocrystals are oxidations, esterifications, amidations, carbamations and etherifications. More recently nucleophilic substitutions have been used to introduce more complex functionality to cellulose nanocrystals. Multi-step modifications are also considered. This review emphasizes quantification of modification at the nanocrystal surface in terms of degree of substitution and the validity of conclusions drawn from different analysis techniques in this area. The mechanisms of the modification reactions are presented and considered with respect to the effect on the outcome of the reactions. While great strides have been made in the quality of analytical data published in the field of cellulose nanocrystal modification, there is still vast scope for improvement, both in data quality and the quality of analysis of data. Given the difficulty of surface analysis, crosschecking of results from different analysis techniques is fundamental for the development of reliable cellulose nanocrystal modification techniques. 56. Inteligencia emocional y actividad fÃsica OpenAIRE GarcÃa Montilla, Virginia 2015-01-01 En el presente trabajo trató la inteligencia emocional en la actividad fÃsica desde la perspectiva de la formación inicial. Como futuros profesionales del sector, uno de nuestros principales atributos será el saber trabajar esta inteligencia emocional tanto a traves de la actividad fÃsica, como para obtener un mejor rendimiento a nivel deportivo. 57. Inteligencia emocional y actividad fÃsica OpenAIRE GarcÃa Montilla, Virginia 2015-01-01 En el presente trabajo trató la inteligencia emocional en la actividad fÃsica desde la perspectiva de la formación inicial. Como futuros profesionales del sector, uno de nuestros principales atributos será el saber trabajar esta inteligencia emocional tanto a traves de la actividad fÃsica, como para obtener un mejor rendimiento a nivel deportivo. 58. Actividad antioxidante de extractos de diez basidiomicetos comestibles en Guatemala OpenAIRE Karen Belloso; Ivonne González; Rebeca Suárez; Armando Cáceres 2015-01-01 Los antioxidantes son esenciales en el cuerpo humano para prevenir el daño oxidativo. Estas substancias pueden obtenerse de diversas fuentes como frutas, plantas y hongos. En Guatemala, diversas especies de hongos comestibles son comercializadas y consumidas, sin embargo su actividad antioxidante no ha sido documentada en el paÃs. El objetivo de este estudio fue determinar la actividad antioxidante de extractos acuosos y etanólicos obtenidos de diez especies de basidiomicetos comestibles (Aga... 59. Nanomechanics of cellulose crystals and cellulose-based polymer composites Science.gov (United States) Pakzad, Anahita Cellulose-polymer composites have potential applications in aerospace and transportation areas where lightweight materials with high mechanical properties are needed. In addition, these economical and biodegradable composites have been shown to be useful as polymer electrolytes, packaging structures, optoelectronic devices, and medical implants such as wound dressing and bone scaffolds. In spite of the above mentioned advantages and potential applications, due to the difficulties associated with synthesis and processing techniques, application of cellulose crystals (micro and nano sized) for preparation of new composite systems is limited. Cellulose is hydrophilic and polar as opposed to most of common thermoplastics, which are non-polar. This results in complications in addition of cellulose crystals to polymer matrices, and as a result in achieving sufficient dispersion levels, which directly affects the mechanical properties of the composites. As in other composite materials, the properties of cellulose-polymer composites depend on the volume fraction and the properties of individual phases (the reinforcement and the polymer matrix), the dispersion quality of the reinforcement through the matrix and the interaction between CNCs themselves and CNC and the matrix (interphase). In order to develop economical cellulose-polymer composites with superior qualities, the properties of individual cellulose crystals, as well as the effect of dispersion of reinforcements and the interphase on the properties of the final composites should be understood. In this research, the mechanical properties of CNC polymer composites were characterized at the macro and nano scales. A direct correlation was made between: - Dispersion quality and macro-mechanical properties Nanomechanical properties at the surface and tensile properties - CNC diameter and interphase thickness. Lastly, individual CNCs from different sources were characterized and for the first time size-scale effect on 60. Ionic liquid processing of cellulose. Science.gov (United States) Wang, Hui; Gurau, Gabriela; Rogers, Robin D 2012-02-21 Utilization of natural polymers has attracted increasing attention because of the consumption and over-exploitation of non-renewable resources, such as coal and oil. The development of green processing of cellulose, the most abundant biorenewable material on Earth, is urgent from the viewpoints of both sustainability and environmental protection. The discovery of the dissolution of cellulose in ionic liquids (ILs, salts which melt below 100 °C) provides new opportunities for the processing of this biopolymer, however, many fundamental and practical questions need to be answered in order to determine if this will ultimately be a green or sustainable strategy. In this critical review, the open fundamental questions regarding the interactions of cellulose with both the IL cations and anions in the dissolution process are discussed. Investigations have shown that the interactions between the anion and cellulose play an important role in the solvation of cellulose, however, opinions on the role of the cation are conflicting. Some researchers have concluded that the cations are hydrogen bonding to this biopolymer, while others suggest they are not. Our review of the available data has led us to urge the use of more chemical units of solubility, such as 'g cellulose per mole of IL' or 'mol IL per mol hydroxyl in cellulose' to provide more consistency in data reporting and more insight into the dissolution mechanism. This review will also assess the greenness and sustainability of IL processing of biomass, where it would seem that the choices of cation and anion are critical not only to the science of the dissolution, but to the ultimate 'greenness' of any process (142 references). « 1 2 3 4 5

» « 2 3 4 5 6 » 61. Plant cellulose synthesis: CESA proteins crossing kingdoms. Science.gov (United States) Kumar, Manoj; Turner, Simon 2015-04-01 Cellulose is a biopolymer of considerable economic importance. It is synthesised by the cellulose synthase complex (CSC) in species ranging from bacteria to higher plants. Enormous progress in our understanding of bacterial cellulose synthesis has come with the recent publication of both the crystal structure and biochemical characterisation of a purified complex able to synthesis cellulose in vitro. A model structure of a plant CESA protein suggests considerable similarity between the bacterial and plant cellulose synthesis. In this review article we will cover current knowledge of how plant CESA proteins synthesise cellulose. In particular the focus will be on the lessons learned from the recent work on the catalytic mechanism and the implications that new data on cellulose structure has for the assembly of CESA proteins into the large complex that synthesis plant cellulose microfibrils. 62. Characterization of Cellulose Synthesis in Plant Cells Directory of Open Access Journals (Sweden) Samaneh Sadat Maleki 2016-01-01 Full Text Available Cellulose is the most significant structural component of plant cell wall. Cellulose, polysaccharide containing repeated unbranched β (1-4 D-glucose units, is synthesized at the plasma membrane by the cellulose synthase complex (CSC from bacteria to plants. The CSC is involved in biosynthesis of cellulose microfibrils containing 18 cellulose synthase (CesA proteins. Macrofibrils can be formed with side by side arrangement of microfibrils. In addition, beside CesA, various proteins like the KORRIGAN, sucrose synthase, cytoskeletal components, and COBRA-like proteins have been involved in cellulose biosynthesis. Understanding the mechanisms of cellulose biosynthesis is of great importance not only for improving wood production in economically important forest trees to mankind but also for plant development. This review article covers the current knowledge about the cellulose biosynthesis-related gene family. 63. Development of nonflammable cellulosic foams Science.gov (United States) Luttinger, M. 1972-01-01 The development of a moldable cellulosic foam for use in Skylab instrument storage cushions is considered. Requirements include density of 10 lb cu ft or less, minimal friability with normal handling, and nonflammability in an atmosphere of 70 percent oxygen and 30 percent nitrogen at 6.2 psia. A study of halogenated foam components was made, including more highly chlorinated binders, halogen-containing additives, and halogenation of the cellulose. The immediate objective was to reduce the density of the foam through reduction in inorganic phosphate without sacrificing flame-retarding properties of the foams. The use of frothing techniques was investigated, with particular emphasis on a ureaformaldehyde foam. Halogen-containing flame retardants were deemphasized in favor of inorganic salts and the preparation of phosphate and sulphate esters of cellulose. Utilization of foam products for civilian applications was also considered. 64. Biocompatibility of Bacterial Cellulose Based Biomaterials OpenAIRE 2012-01-01 Some bacteria can synthesize cellulose when they are cultivated under adequate conditions. These bacteria produce a mat of cellulose on the top of the culture medium, which is formed by a three-dimensional coherent network of pure cellulose nanofibers. Bacterial cellulose (BC) has been widely used in different fields, such as the paper industry, electronics and tissue engineering due to its remarkable mechanical properties, conformability and porosity. Nanocomposites based on BC have received... 65. The trafficking and behavior of cellulose synthase and a glimpse of potential cellulose synthesis regulators Institute of Scientific and Technical Information of China (English) Logan BASHLINE; Juan DU; Ying GU 2011-01-01 Cellulose biosynthesis is a topic of intensive research not only due to the significance of cellulose in the integrity of plant cell walls,but also due to the potential of using cellulose,a natural carbon source,in the production ot biofuels.Characterization of the composition,regulation,and trafficking of cellulose synthase complexes (CSCs) is critical to an understanding of cellulose biosynthesis as well as the characterization of additional proteins that contribute to the production of cellulose either through direct interactions with CSCs or through indirect mechanisms.In this review,a highlight of a few proteins that appear to affect cellulose biosynthesis,which includes:KORRIGAN (KOR),Cellulose SynthaseInteractive Protein 1 (CSI1),and the poplar microtubule-associated protein,PttMAP20,will accompany a description of cellulose synthase (CESA) behavior and a discussion of CESA trafficking compartments that might act in the regulation of cellulose biosynthesis. 66. Cellulose nanomaterials review: structure, properties and nanocomposites Science.gov (United States) Robert J. Moon; Ashlie Martini; John Nairn; John Simonsen; Jeff Youngblood 2011-01-01 This critical review provides a processing-structure-property perspective on recent advances in cellulose nanoparticles and composites produced from them. It summarizes cellulose nanoparticles in terms of particle morphology, crystal structure, and properties. Also described are the self-assembly and rheological properties of cellulose nanoparticle suspensions. The... 67. Bioengineering cellulose-hemicellulose networks in plants NARCIS (Netherlands) Obembe, O. 2006-01-01 The interactions between cellulose and hemicellulose in the cell walls are important in the industrial application of the cellulose (natural) fibres. We strive to modify these interactions (i) by interfering with cellulose biosynthesis and (ii) by direct interference of the 68. Adsorption and desorption of cellulose derivatives NARCIS (Netherlands) Hoogendam, C.W. 1998-01-01 Cellulose derivatives, in particular carboxymethyl cellulose (CMC) are used in many (industrial) applications. The aim of this work is to obtain insight into the adsorption mechanism of cellulose derivatives on solid-liquid interfaces. In chapter 1 69. Adsorption and desorption of cellulose derivatives. NARCIS (Netherlands) Hoogendam, C.W. 1998-01-01 Cellulose derivatives, in particular carboxymethyl cellulose (CMC) are used in many (industrial) applications. The aim of this work is to obtain insight into the adsorption mechanism of cellulose derivatives on solid-liquid interfaces.In chapter 1 of this thesis we discuss some appl 70. Effect of the steam explosion pretreatment on enzymatic hydrolysis of eucalyptus wood and sweet sorghum baggages; Efecto del pretratamiento con explosion por vapor en la hidrolisis enzimatica de madera de eucalipto y bagazo de sorgo Energy Technology Data Exchange (ETDEWEB) Negro, M. J.; Martinez, J. M.; Manero, J.; Saez, F.; Martin, C. 1991-07-01 The effect of steam explosion treatment on the enzymatic hydrolysis yield of two different lignocellulosic substrates is studied. Raw materials have been pretreated in a pilot plant designed to work in batch and equipped with a reactor vessel of 2 1 working volume where biomass was heated at the desired temperature and then exploded and recovered in a cyclone. Temperatures from 190 to 230 degree celsius and reaction times from 2 to 8 min. have been assayed. The efficiency of the steam explosion treatment has been evaluated on the composition of the lignocellulosic materials as well as on their enzymatic hydrolysis yield using a cellulolytic complex from T. reesel. Results show a high solubilization rate of hemicelluloses and variable losses of cellulose and lignin depending on the conditions tested. Enzymatic hydrolysis yields of both substrates experimented remarkable increments, corresponding the highest values obtained to 210 degree celsius; 2 min. and 21O degree celsius; 4 min. for sorghum bagasse and eucalyptus wood respectively. (Author) 13 refs. 71. Ionic Liquids and Cellulose: Dissolution, Chemical Modification and Preparation of New Cellulosic Materials Directory of Open Access Journals (Sweden) Mehmet Isik 2014-07-01 Full Text Available Due to its abundance and a wide range of beneficial physical and chemical properties, cellulose has become very popular in order to produce materials for various applications. This review summarizes the recent advances in the development of new cellulose materials and technologies using ionic liquids. Dissolution of cellulose in ionic liquids has been used to develop new processing technologies, cellulose functionalization methods and new cellulose materials including blends, composites, fibers and ion gels. 72. Impact of Biofield Treatment on Chemical and Thermal Properties of Cellulose and Cellulose Acetate OpenAIRE Trivedi, Mahendra Kumar 2015-01-01 Cellulose being an excellent biopolymer has cemented its place firmly in many industries as a coating material, textile, composites, and biomaterial applications. In the present study, we have investigated the effect of biofield treatment on physicochemical properties of cellulose and cellulose acetate. The cellulose and cellulose acetate were exposed to biofield and further the chemical and thermal properties were investigated. X-ray diffraction study asserted that the biofield treatment did... 73. Physicotechnical, spectroscopic and thermogravimetric properties of powdered cellulose and microcrystalline cellulose derived from groundnut shells OpenAIRE Chukwuemeka P. Azubuike; Jimson O. Odulaja; Augustine O Okhamafe 2012-01-01 α-Cellulose and microcrystalline cellulose powders, derived from agricultural waste products, that have for thepharmaceutical industry, desirable physical (flow) properties were investigated. α–Cellulose (GCN) wasextracted from groundnut shell (an agricultural waste product) using a non-dissolving method based oninorganic reagents. Modification of this α -cellulose was carried out by partially hydrolysing it with 2Nhydrochloric acid under reflux to obtain microcrystalline cellulose (MCGN). Th... 74. Atomic force microscopy study of cellulose surface interaction controlled by cellulose binding domains OpenAIRE Nigmatullin, R.; Lovitt, R.; Wright, C; Linder, M.; Nakari-Setälä, T; Gama, F. M. 2004-01-01 Colloidal probe microscopy has been used to study the interaction between model cellulose surfaces and the role of cellulose binding domain (CBD), peptides specifically binding to cellulose, in interfacial interaction of cellulose surfaces modified with CBDs. The interaction between pure cellulose surfaces in aqueous electrolyte solution is dominated by double layer repulsive forces with the range and magnitude of the net force dependent on electrolyte concentration. AFM imaging reve... 75. Actividad antimicrobiana del OLEOZON® sobre Staphylococcus aureus y Pseudomonas aeruginosa OpenAIRE V. Curtiellas; M Gómez; O. Ledea; Fernández, I.; Sánchez, E. 2005-01-01 La actividad antimicrobiana de los aceites vegetales ozonizados suele atribuirse a la acción de los compuestos peroxÃdicos presentes en los mismos sobre las biomoléculas más sensibles al ataque oxidante, como son los lÃpidos insaturados y las proteÃnas que presentan grupos sulfidrilos (SH). Con el objetivo de caracterizar la actividad in vitro del aceite de girasol ozonizado, OLEOZON®, se realizó un estudio empleando las cepas S. aureus ATCC 25923 y P. aeruginosa ATCC 27853. Se determinaron l... 76. Actividades extraescolares: ¿De verdad llevan a la violencia? OpenAIRE Peños Cañadas, Erika 2014-01-01 A lo largo del tiempo, se ha llegado a creer que ciertas actividades extraescolares incitaban a llevar a cabo conductas agresivas contra los demás, pero se ha podido comprobar que en realidad no es asÃ, que lo que de verdad hace que los niños tengan conductas agresivas en las actividades extraescolares es una serie de factores que influyen directamente sobre el niño. Existen una serie de claves que nos ayudan a encontrar el motivo por el que puede existir esa agresividad y gracias a ellos pod... 77. Composiciones conservantes de aceitunas con actividad antifúngica OpenAIRE Bautista-Gallego, J.; Arroyo López, Francisco Noé; Garrido Fernández, A.; GarcÃa GarcÃa, Pedro; López-López, Antonio; RodrÃguez-Gómez, Francisco J. 2010-01-01 [ES] La presente invención se refiere a nuevas composiciones conservantes de aceitunas con actividad antiñmgica que comprenden: a. cloruro sódico; b. al menos un ácido con propiedades conservantes; y c. al menos una sal de cinc. Además la presente invención se refiere al procedimiento para la conservación de alimentos mediante dichas composiciones con actividad antiñmgica y al uso de la composición para la conservación de aceitunas frente a microorganismos del reino fungÃ. 78. Las actividades agroambientales en Canarias ante los retos de futuro OpenAIRE Ramón DÃaz Hernández; Juan Manuel Parreño Castellano 2013-01-01 Las actividades primarias en Canarias, y en especial, la agricultura, presentan una situación de crisis que amenaza con aumentar el abandono de fincas, la reducción de la producción y la pérdida de población rural. Los valores económicos, sociales, ambientales y culturales que caracterizan a estas actividades aconsejan una apuesta más decidida por el mantenimiento del sector, para lo que es necesario replantear en muchas zonas el desarrollo agrario integral vinculándolo a la conservación y re... 79. Foaming of Ethyl Hydroxyethyl Cellulose OpenAIRE Carrillo Agilera, Marc 2015-01-01 The current depletion of petroleum resources together with environmental issues have led to new approaches in plastic manufacturing. This trend involves using ecofriendly materials coming from renewable resources. Good candidates for this, due to their properties and availability, are the cellulose derivatives. Some of them, such as hydroxypropyl methylcellulose (HPMC), showed in previous studies a promising behavior when making polymeric foams. Unfortunately, the corresponding... 80. Cellulose nanomaterials review: structure, properties and nanocomposites. Science.gov (United States) Moon, Robert J; Martini, Ashlie; Nairn, John; Simonsen, John; Youngblood, Jeff 2011-07-01 This critical review provides a processing-structure-property perspective on recent advances in cellulose nanoparticles and composites produced from them. It summarizes cellulose nanoparticles in terms of particle morphology, crystal structure, and properties. Also described are the self-assembly and rheological properties of cellulose nanoparticle suspensions. The methodology of composite processing and resulting properties are fully covered, with an emphasis on neat and high fraction cellulose composites. Additionally, advances in predictive modeling from molecular dynamic simulations of crystalline cellulose to the continuum modeling of composites made with such particles are reviewed (392 references). « 2 3 4 5 6 » « 3 4 5 6 7 »

81. Structure and engineering of celluloses. Science.gov (United States) Pérez, Serge; Samain, Daniel 2010-01-01 This chapter collates the developments and conclusions of many of the extensive studies that have been conducted on cellulose, with particular emphasis on the structural and morphological features while not ignoring the most recent results derived from the elucidation of unique biosynthetic pathways. The presentation of structural and morphological data gathered together in this chapter follows the historical development of our knowledge of the different structural levels of cellulose and its various organizational levels. These levels concern features such as chain conformation, chain polarity, chain association, crystal polarity, and microfibril structure and organization. This chapter provides some historical landmarks related to the evolution of concepts in the field of biopolymer science, which parallel the developments of novel methods for characterization of complex macromolecular structures. The elucidation of the different structural levels of organization opens the way to relating structure to function and properties. The chemical and biochemical methods that have been developed to dissolve and further modify cellulose chains are briefly covered. Particular emphasis is given to the facets of topochemistry and topoenzymology where the morphological features play a key role in determining unique physicochemical properties. A final chapter addresses what might be considered tomorrow's goal in amplifying the economic importance of cellulose in the context of sustainable development. Selected examples illustrate the types of result that can be obtained when cellulose fibers are no longer viewed as inert substrates, and when the polyhydroxyl nature of their surfaces, as well as their entire structural complexity, are taken into account. Copyright © 2010 Elsevier Inc. All rights reserved. 82. Cellulose nanomaterials in water treatment technologies. Science.gov (United States) Carpenter, Alexis Wells; de Lannoy, Charles-François; Wiesner, Mark R 2015-05-05 Cellulose nanomaterials are naturally occurring with unique structural, mechanical and optical properties. While the paper and packaging, automotive, personal care, construction, and textiles industries have recognized cellulose nanomaterials' potential, we suggest cellulose nanomaterials have great untapped potential in water treatment technologies. In this review, we gather evidence of cellulose nanomaterials' beneficial role in environmental remediation and membranes for water filtration, including their high surface area-to-volume ratio, low environmental impact, high strength, functionalizability, and sustainability. We make direct comparison between cellulose nanomaterials and carbon nanotubes (CNTs) in terms of physical and chemical properties, production costs, use and disposal in order to show the potential of cellulose nanomaterials as a sustainable replacement for CNTs in water treatment technologies. Finally, we comment on the need for improved communication and collaboration across the myriad industries invested in cellulose nanomaterials production and development to achieve an efficient means to commercialization. 83. Actividad metacognitiva en estudiantes universitarios: un estudio preliminar Directory of Open Access Journals (Sweden) Kelly Cantillo Anaya 2014-01-01 Full Text Available Esta investigación tuvo como objetivo dar cuenta de niveles de actividad metacognitiva en estudiantes universitarios, estableciendo diferencias en función de variables como la edad y semestre acadé - mico de los participantes, para lo cual se utilizó el Cuestionario de Autorreporte de Actividad Metacognitiva. En el estudio participa - ron 95 estudiantes de ambos sexos, que cursaban primero, quinto y décimo semestre en un programa de psicologÃa de una universidad pública. Los datos arrojados permiten establecer que la actividad metacognitiva, en relación tanto con el semestre como con la edad en la muestra estudiada, se ubica en un nivel medio bajo. En ninguno de los semestres, ni en los rangos de edad se registran niveles altos en los componentes de Conciencia, Control y Autopoiesis. No se encontró correlación significativa entre actividad metacognitiva y semestre aca - démico cursado, como tampoco con la edad. 84. ACTIVIDAD ANTIFUNGICA DEL EXTRACTO DE Brosimum rubescens (Palisangre Directory of Open Access Journals (Sweden) MarÃa FachÃn-Espinar 2012-12-01 Full Text Available El extracto etanólico y sus fracciones cromatográficas del tallo de Brosimum rubencens Taubert fueron evaluados para determinar la actividad antifúngica in vitro mediante el método de macrodilución para hongos filamentosos. El tamizaje fitoquÃmico del extracto etanólico del tallo de B. rubencens evidenció la presencia de cumarinas, quinonas y taninos, además de flavonoides y triterpenos; para el estudio de la actividad antifúngica se utilizó cepas de Trichosporum rubrum ATCC 28188 y Trichosporum mentagrophytes ATCC 24953. En ambos casos la fracción insoluble en dilución ácida evidenció mayor actividad antifúngica que el extracto etanólico contra dermatofitos. El fraccionamiento del extracto etanólico permitió inferir que el responsables de la actividad se debe a los fitocomplejos, no asà a las fracciones frente a T. rubrum ATCC 28188. 85. Riesgos antrópicos generados por la actividad minera Directory of Open Access Journals (Sweden) Ana Violeta Argüello MejÃa 2013-10-01 Full Text Available Las actividades productivas generan riesgos antrópicos [1] a mediano y largo plazo. La zona de estudio se ubica en las Parroquias de Pomasqui, San Antonio y CalacalÃ, donde se han producido riesgos debido a las actividades humanas, en este caso, por la explotación de las canteras para abastecer el mercado de la construcción del Distrito Metropolitano de Quito. La investigación propone determinar los riesgos antrópicos generados por la actividad minera. Los pobladores de la zona identifican que la minerÃa artesanal en sus inicios constituyó una fuente de trabajo, donde sus familias también se involucraban. Actualmente, se observa que en la mayorÃa de las canteras se utiliza maquinaria especializada y no participan los trabajadores de la zona. Los taludes de las canteras son de 80o y 90o grados, generando amenazas para los trabajadores y moradores de las viviendas aledañas. Uno de los mayores impactos es la contaminación del aire, sin embargo, el suelo y los cursos de agua están siendo afectados por los desperdicios que produce la actividad minera. La población, que está expuesta permanentemente al polvo ocasionado por las canteras y al transporte de material, acusa enfermedades de tipo respiratorio. Asà mismo, el ruido ocasionado por el transporte constituye una molestia constante para los pobladores. 86. ACTIVIDAD ANTIFUNGICA DEL EXTRACTO DE Brosimum rubescens (Palisangre Directory of Open Access Journals (Sweden) MarÃa FachÃn Espinar 2012-12-01 Full Text Available El extracto etanólico y sus fracciones cromatográficas del tallo de Brosimum rubencens Taubert fueron evaluados para determinar la actividad antifúngica in vitro mediante el método de macrodilución para hongos filamentosos. El tamizaje fitoquÃmico del extracto etanólico del tallo de B. rubencens evidenció la presencia de cumarinas, quinonas y taninos, además de flavonoides y triterpenos; para el estudio de la actividad antifúngica se utilizó cepas de Trichosporum rubrum ATCC 28188 y Trichosporum mentagrophytes ATCC 24953. En ambos casos la fracción insoluble en dilución ácida evidenció mayor actividad antifúngica que el extracto etanólico contra dermatofitos. El fraccionamiento del extracto etanólico permitió inferir que el responsable de la actividad se debe a los fitocomplejos, no asà a las fracciones frente a T. rubrum ATCC 28188. 87. Actividades en la adolescencia: Experiencias óptimas y autopercepciones Directory of Open Access Journals (Sweden) Alejandra Daniela Calero 2016-12-01 Full Text Available El objetivo de este trabajo fue comparar los niveles de experiencias óptimas (EO que los adolescentes reportan en distintas actividades del contexto escolar y extraescolar y analizar cómo se relacionan estos niveles con el autoconcepto y autoestima en la población adolescente de la Ciudad Autónoma de Buenos Aires, Argentina (CABA-AR. Para ello se administró el Inventario Breve de EO y el Perfil de Autopercepción a 399 adolescentes concurrentes a escuelas de educación media de la CABA-AR. Se realizó un ANOVA de medidas repetidas con efecto principal intrasujeto para comparar las EO en cada actividad y un análisis de correlación para estudiar la relación entre EO y el autoconcepto y autoestima. Entre los resultados se encontró que los adolescentes experimentan mayores niveles de ocurrencia de EO en las actividades extracurriculares. Con respecto al autoconcepto y autoestima, las relaciones halladas fueron en todos los casos positivas y mostraron diferencias según el tipo de actividad en el cual se reportaban las EO. 88. Aspectos generales sobre colisión de actividades peligrosas OpenAIRE 2006-01-01 El estudio realizado parte de una acercamiento teórico a la presunción establecida en el artÃculo 2356 de Código Civil Colombiano, en el que la doctrina y la jurisprudencia han afirmado que es posible identificar la responsabilidad civil por los daños causados en el ejercicio de actividades peligrosas. 89. Ultrasound mediated enzymatic hydrolysis of cellulose and carboxymethyl cellulose. Science.gov (United States) Sulaiman, Ahmad Ziad; Ajit, Azilah; Chisti, Yusuf 2013-01-01 A recombinant Trichoderma reesei cellulase was used for the ultrasound-mediated hydrolysis of soluble carboxymethyl cellulose (CMC) and insoluble cellulose of various particle sizes. The hydrolysis was carried out at low intensity sonication (2.4-11.8 W cm(-2) sonication power at the tip of the sonotrode) using 10, 20, and 40% duty cycles. [A duty cycle of 10%, for example, was obtained by sonicating for 1 s followed by a rest period (no sonication) of 9 s.] The reaction pH and temperature were always 4.8 and 50°C, respectively. In all cases, sonication enhanced the rate of hydrolysis relative to nonsonicated controls. The hydrolysis of CMC was characterized by Michaelis-Menten kinetics. The Michaelis-Menten parameter of the maximum reaction rate Vmax was enhanced by sonication relative to controls, but the value of the saturation constant Km was reduced. The optimal sonication conditions were found to be a 10% duty cycle and a power intensity of 11.8 W cm(-2) . Under these conditions, the maximum rate of hydrolysis of soluble CMC was nearly double relative to control. In the hydrolysis of cellulose, an increasing particle size reduced the rate of hydrolysis. At any fixed particle size, sonication at a 10% duty cycle and 11.8 W cm(-2) power intensity improved the rate of hydrolysis relative to control. Under the above mentioned optimal sonication conditions, the enzyme lost about 20% of its initial activity in 20 min. Sonication was useful in accelerating the enzyme catalyzed saccharification of cellulose. © 2013 American Institute of Chemical Engineers. 90. Actividad antimicrobiana de Waltheria indica y Acacia farnesiana Directory of Open Access Journals (Sweden) Nidia M. Rojas Hernández 2009-01-01 Full Text Available Entre las plantas medicinales empleadas en Tierra Caliente, estado de Guerrero, México, se encuentran el Güinar (Waltheria indica L., Esterculiaceae y el Huizache (Acacia farnesiana L. Willd, Mimosaceae. En ambas, la infusión de la raÃz se usa popularmente para las diarreas. Con la finalidad de validar las propiedades que se les atribuyen a estas especies vegetales, el presente trabajo tuvo como objetivo evaluar la actividad antimicrobiana in vitro de los extractos acuosos y etanólicos preparados con las raÃces de ambas plantas. A estos extractos, se les determinó el rendimiento de sólidos solubles totales y se les realizó el análisis fitoquÃmico general. La actividad antimicrobiana se evaluó frente a 25 cultivos bacterianos, dos cepas de hongos filamentosos y 13 cepas de siete especies de levaduras del género Candida. En ambas plantas, los extractos etanólicos tuvieron mayor actividad que los acuosos. Los extractos etanólicos de estas especies vegetales afectaron el crecimiento de siete cepas bacterianas, lo cual correspondió al 28 % de los cultivos evaluados. Esta actividad fue bacteriostática y bactericida para los dos extractos, a los que se les determinaron las Concentraciones MÃnimas Inhibitoria (CMI y Bactericida (CMB frente a los cultivos sensibles. Solo se detectó actividad antifúngica por el extracto de W. indica sobre la cepa de C. utilis. La acción sobre bacterias enteropatógenas in vitro valida el uso de estas plantas en medicina tradicional y reafirma la necesidad de estudios toxicológicos para asegurar la inocuidad de su uso. 91. Cellulose nanocrystal submonolayers by spin coating. Science.gov (United States) Kontturi, Eero; Johansson, Leena-Sisko; Kontturi, Katri S; Ahonen, Päivi; Thüne, Peter C; Laine, Janne 2007-09-11 Dilute concentrations of cellulose nanocrystal solutions were spin coated onto different substrates to investigate the effect of the substrate on the nanocrystal submonolayers. Three substrates were probed: silica, titania, and amorphous cellulose. According to atomic force microscopy (AFM) images, anionic cellulose nanocrystals formed small aggregates on the anionic silica substrate, whereas a uniform two-dimensional distribution of nanocrystals was achieved on the cationic titania substrate. The uniform distribution of cellulose nanocrystal submonolayers on titania is an important factor when dimensional analysis of the nanocrystals is desired. Furthermore, the amount of nanocrystals deposited on titania was multifold in comparison to the amounts on silica, as revealed by AFM image analysis and X-ray photoelectron spectroscopy. Amorphous cellulose, the third substrate, resulted in a somewhat homogeneous distribution of the nanocrystal submonolayers, but the amounts were as low as those on the silica substrate. These differences in the cellulose nanocrystal deposition were attributed to electrostatic effects: anionic cellulose nanocrystals are adsorbed on cationic titania in addition to the normal spin coating deposition. The anionic silica surface, on the other hand, causes aggregation of the weakly anionic cellulose nanocrystals which are forced on the repulsive substrate by spin coating. The electrostatically driven adsorption also influences the film thickness of continuous ultrathin films of cellulose nanocrystals. The thicker films of charged nanocrystals on a substrate of opposite charge means that the film thickness is not independent of the substrate when spin coating cellulose nanocrystals in the ultrathin regime ( C3–OH >> C6–OH in zinc chloride solution, and this is clearly different from other researches. Most importantly, this work confirms that the method to regiocontrolled synthesis cellulose-based derivative polymers by regiobreaking hydrogen bonds is feasible. It is strongly believed that the new discovery may give a novel, environmental, simple and inexpensive method to modify cellulose chemically with various side chains grafted on a given hydroxyl, through liberating hydroxyl as reactive group from hydrogen bonds broken selectively by different solvents. 339. Efectos de la actividad fÃsica sobre la actividad cerebral y la variabilidad de la frecuencia cardiaca en mayores OpenAIRE Valero Herreros, Montse 2011-01-01 Descripció del recurs: 28-06-2011 La presente tesis doctoral se enmarca dentro de esta lÃnea de investigación, que agrupa diferentes disciplinas como la psicologÃa de la actividad fÃsica y la psicologÃa de la salud, la neurociencia cognitiva y la psicologÃa de la vejez. Con la utilización de una de las técnicas de neuroimagen menos invasivas y con mayor resolución espacio-temporal, la magnetoencefalografÃa, se han estudiado los efectos de la práctica regular de actividad fÃsica en la activ... 340. Actividades extraescolares y rendimiento académico en alumnos de primaria Directory of Open Access Journals (Sweden) Ramón Cladellas Pros 2013-08-01 Full Text Available El objetivo de este trabajo es valorar la posible incidencia en el rendimiento académico de alumnos de primaria, de la realización -o no- de actividades extraescolares, según su tipologÃa (recreativas, cognitivas o ambas y el número de horas de actividades realizadas. La muestra final estaba formada por un total de 721 alumnos de primaria (366 niños y 355 niñas procedentes de diversos centros escolares de las comarcas catalanas y de las Islas Baleares. Se facilitó a los padres de los alumnos un cuestionario en el que debÃan indicar las notas obtenidas en diferentes materias (matemáticas, catalán, castellano, idiomas, gimnasia y plástica y responder datos relacionados con la realización de actividades extraescolares. Los resultados muestran cómo la realización de algún tipo de actividad extraescolar, sea del tipo que sea, mejora el rendimiento académico de los niños y niñas de la muestra. La sola realización de algún tipo de actividad (ya sea recreativa o cognitiva, o una combinación de ambas, incide positivamente y significativamente en los resultados obtenidos en todas las materias estudiadas, a excepción de las asignaturas de matemáticas, gimnasia y plástica. Asimismo, un número elevado de horas de actividades extraescolares (más de 10 horas y media a la semana afecta negativamente a los resultados obtenidos en todas las materias menos en gimnasia. « 15 16 17 18 19 » « 16 17 18 19 20 » 341. ECOLOGY SAFE METHOD OF OBTAINING FROM FIR-WOOD THE CELLULOSIC PRODUCT WITH HIGH CONTENT OF ALFA-CELLULOSE OpenAIRE Владимир ÐлекÑандрович ЛевданÑкий; ÐлекÑандр Владимирович ЛевдР°Ð½Ñкий; Ð‘Ð¾Ñ€Ð¸Ñ Ðиколаевич Кузнецов 2014-01-01 The «green» method of obtaining from fir-wood the cellulosic product with high content of alpha-cellulose was developed. It consists of the stage of wood delignification by hydrogen peroxide in the medium «acetic acid – water – sulfuric acid catalyst» and of the stage of alkaline treatment by NaOH. Preparation conditions were selected which allow to obtain with an acceptable yield (30–31% mas.) the cellulosic product containing 97,3–98,0% mas. of alpha-cellulose. 342. Manganese-containing cellulose nanocomposites: the restrain effect of cellulose treated with NaOH/urea aqueous solutions. Science.gov (United States) Ma, Ming-Guo; Deng, Fu; Yao, Ke 2014-10-13 In this article, the manganese-containing cellulose nanocomposites were obtained using microcrystalline cellulose and Mn(CH3COO)2 · 4H2O in the NaOH/urea aqueous solutions by a efficient microwave-assisted method. The effects of the heating time and Mn(CH3COO)2 · 4H2O concentration on the cellulose nanocomposites were investigated. It was found that the microcrystalline cellulose pretreated with NaOH/urea aqueous solutions played an important role in the phase, shape, and thermal stability of manganese-containing cellulose nanocomposites. Well-crystalline phases of manganese oxides were not observed in the manganese-containing cellulose nanocomposites. Furthermore, well-crystalline phases of manganese oxides were not also observed by thermal treatment of the manganese-containing cellulose nanocomposites at 600 °C for 3h. These results could be attributed to the restrain effect of cellulose treated with NaOH/urea aqueous solutions. It was supposed the possible mechanism during the phase transformation of cellulose nanocomposites. 343. The correlation between the enzymatic saccharification and the multidimensional structure of cellulose changed by different pretreatments

OpenAIRE Cui, Ting; Li, Jihong; Yan, Zhipei; Yu, Menghui; Li, Shizhong 2014-01-01 Background The bioconversion of cellulose into simple sugars or chemicals has attracted extensive attention in recent decades. The crystal allomorphs of cellulose are key factor affecting cellulose saccharification. However, due to the influence of lignin, hemicelluloses, and different characterization methods in the literature, the effect of cellulose allomorphs on cellulose saccharification is still unresolved. Thus, a systematic research on the effect of different cellulose allomorphs on e... 344. Capacidades y actividades en el autocuidado del paciente con pie diabético OpenAIRE Balcázar-Ochoa, Mayra; Escate-RuÃz, Yessenia; Choque-DÃaz, Cristina; Velásquez-Carranza, Doris 2015-01-01 Objetivo: determinar las capacidades y actividades del autocuidado en el paciente con pie diabético. Material y métodos: estudio cuantitativo, descriptivo de corte transversal, la población estuvo conformada por 60 pacientes que se encontraban hospitalizados por presentar pie diabético; se empleó como instrumento el cuestionario sobre capacidades y actividades de autocuidado del paciente con pie diabético, el cual fue elaborado por las investigadoras; la primera parte estuvo conformada por 13... 345. Actividad antioxidante de algas y plantas marinas de la plataforma insular cubana OpenAIRE O Valdés; Hernádez, Y.; Fernández, M. D.; Hernández, I.; Rodriguez,M.; Cano, M.; A. Laguna; DÃaz, C.; Cabrera, B. 2008-01-01 En el presente trabajo se estudia la capacidad antioxidante de varios extractos, acuosos e hidro-alcohólicos obtenidos a partir de algas y plantas marinas de la plataforma insular cubana. A todos los extractos se les determinó su contenido de polifenoles, proteÃnas, lÃpidos y azúcares totales, asà como la actividad Superóxido Dismutasa (SOD). Todos los extractos evaluados mostraron una buena actividad antioxidante, con una CE50 inferior de 0,4 mg.ml-1. El cont... 346. Evaluación de la actividad antihipertensiva de nutraceuticos de fresa silvestre y comercial OpenAIRE Chávez Ramos, Ma. Guadalupe 2013-01-01 La fresa es una frutilla que contiene compuestos nutracéuticos tales como: compuestos fenólicos, flavonoides y antocianinas, los cuales presentan una gran gama de actividades biológicas, incluyendo la actividad antioxidante, anticancerÃgena, antiinflamatoria, antihipertensiva, entre otras. Recientemente se ha reportado que la capacidad antioxidante de los compuestos nutracéuticos de diferentes bayas puede estar involucrada en la reducción de la presión arterial. La hipertensión... 347. Actividad de oxidasa alternativa y respiración mitocondrial en plantas superiores OpenAIRE Beconi, Martha Teresa 1981-01-01 Se estudió la actividad de oxidasa alternativa y la respiración mitocondrial en mitocondrias aisladas de diferentes tejidos de plantas superiores. Incubando tejido de tubérculos de papa en una cámara húmeda (envejecimiento) durante 24 y 48 horas se observó un incremento de la proteÃna mitocondrial con un concomitante aumento en la actividad de oxidasa alternativa. Además en dichas mitocondrias se observó un incremento en el consumo de oxÃgeno y una disminución en el control respiratorio con e... 348. La relevancia del Derecho Aduanero en la actividad financiera del Estado: Reflexiones OpenAIRE Felipe Moreno Yebra 2015-01-01 Introducción. Obtener recursos para cumplir con el gasto público es, quizás, la actividad más importante que tiene el Estado. Sólo asà es dable sostener gastos en infraestructura, asistencia social, educación, cultura, seguridad nacional, entre otros. Para atraer inversión el Estado otorga concesiones a los particulares, que van desde la exención de impuestos, donación de terrenos, gasto en infraestructura, entre otros1. De la actividad financiera del Estado depende la obtención, protección... 349. Un enfoque de trabajo en el aula : la actividad cientÃfica escolar OpenAIRE Paz Villagran, V. 2009-01-01 La investigación que se presenta tiene como objetivo analizar la actividad cientÃfica escolar que se desarrolla con un grupo de estudiantes de 14 y 15 años mientras trabajaban el tema de la nutrición en un Instituto de Educación Secundaria de Barcelona (España). La profesora utiliza diversas modalidades educativas, realiza experimentos, explica, presenta un vÃdeo a sus estudiantes. A través de esas actividades, obtiene textos, resúmenes e informes de prácticas; estos materiales constituyen lo... 350. Actividades creativas en Educación Musical: la composición musical grupal OpenAIRE Hernández Bravo, J.R.; Hernández Bravo, J.A.; Milán Arellano, M.A. 2010-01-01 La educación musical es una de las áreas curriculares que contribuye de manera más decisiva al desarrollo de la creatividad en el alumnado. El aula de música, como espacio ideal para la experimentación y la manifestación libre de ideas y sentimientos, facilita la realización de actividades creativas tanto individuales como grupales. En este artÃculo se recoge un ejemplo de estas actividades en donde, a través de la elaboración en grupo de una composición musical, se constata las aportaciones ... 351. Valoración de la actividad antioxidante de verduras silvestres OpenAIRE Morales, Patricia; Fernández-Ruiz, Virginia; Sánchez Mata, MarÃa de Cortés; Cámara Hurtado, Montaña; Carvalho, Ana Maria; Pardo de Santayana, Manuel; TardÃo, Javier; Isabel C. F. R. Ferreira 2013-01-01 En los últimos años se han llevado a cabo diversos estudios para evaluar el potencial nutricional y funcional de las plantas silvestres comestibles. Algunas de ellas son una buena fuente de compuestos bioactivos y han demostrado tener una interesante actividad biológica como antioxidantes. Por ello, este trabajo tiene como objetivo principal evaluar la actividad biológica in vitro de la parte comestible de 20 verduras silvestres tradicionalmente consumidas en la PenÃnsula Ibérica, cuantifica... 352. Bienestar personal y actividades en la edad adulta tardÃa OpenAIRE González Herero, Vanessa 2008-01-01 El objetivo principal de esta investigación fue examinar cómo el bienestar (bienestar personal, satisfacción vital, felicidad, afecto positivo y afecto negativo) se conectaba en la edad adulta con la participación en las actividades (frecuencia, número y satisfacción con las actividades), y con ciertas dimensiones de la personalidad, tales como la autoestima y el optimismo. Asimismo, se analizó cómo dichas variables se relacionaban con otras de naturaleza sociodemográfica: edad, sexo y situac... 353. Actividades creativas en Educación Musical: la composición musical grupal OpenAIRE Hernández Bravo, J.R.; Hernández Bravo, J.A.; Milán Arellano, M.A. 2010-01-01 La educación musical es una de las áreas curriculares que contribuye de manera más decisiva al desarrollo de la creatividad en el alumnado. El aula de música, como espacio ideal para la experimentación y la manifestación libre de ideas y sentimientos, facilita la realización de actividades creativas tanto individuales como grupales. En este artÃculo se recoge un ejemplo de estas actividades en donde, a través de la elaboración en grupo de una composición musical, se constata las aportaciones ... 354. Objetivos vinculados a la alimentación saludable y actividad fÃsica OpenAIRE Ãlvarez DÃaz, Mirella 2014-01-01 En este trabajo de investigación se han identificado y evaluado los diferentes objetivos relacionados con la alimentación y la actividad fÃsica saludable, en los planes de salud de las Comunidades Autónomas (CCAA) españolas. La investigación se ha desarrollado sobre 14 planes de salud de otras tantas CCAA. En los análisis de situación de salud de la mayorÃa de estos planes, se recogen problemas directamente relacionados con la alimentación y la actividad fÃsica, como son el sobrepeso, la o... 355. Percepciones sociales de las relaciones entre la actividad agro-ganadera y el medio ambiente OpenAIRE RodrÃguez Ortega, Tamara 2013-01-01 La agricultura y la ganaderÃa son actividades controvertidas en el debate actual sobre el equilibrio entre conservación y explotación de los ecosistemas. Resulta pues fundamental conocer y poner en valor aquellas actividades y sistemas de producción más sostenibles ecológica, económica y socialmente. En este contexto, los estudios sobre los valores socio-culturales de la población contribuyen a la definición de la sostenibilidad agro-ganadera y, por tanto, al diseño de polÃticas. En este t... 356. Representaciones Sociales acerca de las Actividades de Educación Temprana para Padres e Hijos OpenAIRE 2016-01-01 En el presente estudio cualitativo de perspectiva etnometodológica, se abordó el tema de las Representaciones Sociales que se han formado los miembros de la comunidad educativa My Baby Studio, acerca de las actividades de educación temprana realizadas para pequeños de 0 a 3 años en este centro educativo ubicado en Tijuana, Baja California. Se partió desde el planteamiento del problema, el cual se definió de la siguiente manera: ¿Cuáles son las Representaciones Sociales acerca de las actividad... 357. Desarrollo de actividades sobre el sonido e influencia en las ideas previas OpenAIRE Ãlvarez MartÃnez, Ana Belén 2013-01-01 El objetivo de este trabajo es, por un lado, desarrollar actividades basadas en el modelo del ciclo de aprendizaje y, por otro lado, evaluar cómo influyen éstas en la construcción de conceptos cientÃficos sobre sonido en estudiantes de Educación Secundaria. Se aplica una prueba inicial para detectar las ideas previas relacionadas con el sonido a alumnos de 4º curso de Educación Secundaria Obligatoria. Después se llevan a cabo las actividades desarrolladas y finalmente se aplica una nueva prue... 358. Hacia un modelo de actividades fisicodeportivas inclusivas en el medio natural OpenAIRE Torrebadella Flix, Xavier 2013-01-01 Presentamos una intervención didáctica ensayada en el Ins. CAR de Sant Cugat del Vallès, en el Ciclo Formativo de grado medio de Conducción de Actividades fÃsico-deportivas en el medio natural. Concretamente abordamos el desarrollo del Crédito de Actividades fÃsicas para personas con discapacidades. A través de un enfoque constructivista, se emprende una metodologÃa de cesión de la autonomÃa, en donde el alumnado despliega un proyecto de profesionalización real consistente en la conducción de... 359. Evaluación de la actividad antihipertensiva de nutraceuticos de fresa silvestre y comercial OpenAIRE Chávez Ramos, Ma. Guadalupe 2013-01-01 La fresa es una frutilla que contiene compuestos nutracéuticos tales como: compuestos fenólicos, flavonoides y antocianinas, los cuales presentan una gran gama de actividades biológicas, incluyendo la actividad antioxidante, anticancerÃgena, antiinflamatoria, antihipertensiva, entre otras. Recientemente se ha reportado que la capacidad antioxidante de los compuestos nutracéuticos de diferentes bayas puede estar involucrada en la reducción de la presión arterial. La hipertensión... 360. Desarrollo de Actividades Productivas Sostenibles en la Reserva Ecológica Manglares Churute OpenAIRE Espol; Guerrero Vergara, Xavier O.; Olmedo Junco, Maite; Espinoza Rodriguez, Carlos 2015-01-01 Proyecto orientado a diversificar las actividades económicas de los pobladores de esta zona, particular del grupo de mujeres de las asociación: Gran mujeres de Churete dotándolas de competencias técnicas especÃficas para menejar actividades lucrativas referentes al turismo, como medio de desarrollo para tal efecto se realizaron una serie de estudios sociales y técnicos en el marco lógico se identificó la problemática de esta zona rural, y se desarrollaron los componentes del proyectos. Gua... « 16 17 18 19 20 » « 17 18 19 20 21 » 361. Regenerating cellulose from ionic liquids for an accelerated enzymatic hydrolysis Energy Technology Data Exchange (ETDEWEB) Zhao, Hua [Savannah State University; Jones, Cecil L [Savannah State University; Baker, Gary A [ORNL; Xia, Shuqian [Tianjin University, Tianjin, China; Olubajo, Olarongbe [Savannah State University; Person, Vernecia [Savannah State University 2009-01-01 The efficient conversion of lignocellulosic materials into fuel ethanol has become a research priority in producing affordable and renewable energy. The pretreatment of lignocelluloses is known to be key to the fast enzymatic hydrolysis of cellulose. Recently, certain ionic liquids (ILs)were found capable of dissolving more than 10 wt% cellulose. Preliminary investigations [Dadi, A.P., Varanasi, S., Schall, C.A., 2006. Enhancement of cellulose saccharification kinetics using an ionic liquid pretreatment step. Biotechnol. Bioeng. 95, 904 910; Liu, L., Chen, H., 2006. Enzymatic hydrolysis of cellulose materials treated with ionic liquid [BMIM]Cl. Chin. Sci. Bull. 51, 2432 2436; Dadi, A.P., Schall, C.A., Varanasi, S., 2007. Mitigation of cellulose recalcitrance to enzymatic hydrolysis by ionic liquid pretreatment. Appl. Biochem. Biotechnol. 137 140, 407 421] suggest that celluloses regenerated from IL solutions are subject to faster saccharification than untreated substrates. These encouraging results offer the possibility of using ILs as alternative and nonvolatile solvents for cellulose pretreatment. However, these studies are limited to two chloride-based ILs: (a) 1-butyl-3methylimidazolium chloride ([BMIM]Cl), which is a corrosive, toxic and extremely hygroscopic solid (m.p. 70 C), and (b) 1-allyl-3-methylimidazolium chloride ([AMIM]Cl), which is viscous and has a reactive side-chain. Therefore, more in-depth research involving other ILs is much needed to explore this promising pretreatment route. For this reason, we studied a number of chloride- and acetate-based ILs for cellulose regeneration, including several ILs newly developed in our laboratory. This will enable us to select inexpensive, efficient and environmentally benign solvents for processing cellulosic biomass. Our data confirm that all regenerated celluloses are less crystalline (58 75% lower) and more accessible to cellulase (>2 times) than untreated substrates. As a result, regenerated Avicel 362. Reaction kinetics of cellulose hydrolysis in subcritical and supercritical water Science.gov (United States) Olanrewaju, Kazeem Bode The uncertainties in the continuous supply of fossil fuels from the crisis-ridden oil-rich region of the world is fast shifting focus on the need to utilize cellulosic biomass and develop more efficient technologies for its conversion to fuels and chemicals. One such technology is the rapid degradation of cellulose in supercritical water without the need for an enzyme or inorganic catalyst such as acid. This project focused on the study of reaction kinetics of cellulose hydrolysis in subcritical and supercritical water. Cellulose reactions at hydrothermal conditions can proceed via the homogeneous route involving dissolution and hydrolysis or the heterogeneous path of surface hydrolysis. The work is divided into three main parts. First, the detailed kinetic analysis of cellulose reactions in micro- and tubular reactors was conducted. Reaction kinetics models were applied, and kinetics parameters at both subcritical and supercritical conditions were evaluated. The second major task was the evaluation of yields

of water soluble hydrolysates obtained from the hydrolysis of cellulose and starch in hydrothermal reactors. Lastly, changes in molecular weight distribution due to hydrothermolytic degradation of cellulose were investigated. These changes were also simulated based on different modes of scission, and the pattern generated from simulation was compared with the distribution pattern from experiments. For a better understanding of the reaction kinetics of cellulose in subcritical and supercritical water, a series of reactions was conducted in the microreactor. Hydrolysis of cellulose was performed at subcritical temperatures ranging from 270 to 340 °C (tau = 0.40--0.88 s). For the dissolution of cellulose, the reaction was conducted at supercritical temperatures ranging from 375 to 395 °C (tau = 0.27--0.44 s). The operating pressure for the reactions at both subcritical and supercritical conditions was 5000 psig. The results show that the rate-limiting step in 363. Evaluating Models of Cellulose Degradation by Fibrobacter succinogenes S85. Directory of Open Access Journals (Sweden) Meagan C Burnet Full Text Available Fibrobacter succinogenes S85 is an anaerobic non-cellulosome utilizing cellulolytic bacterium originally isolated from the cow rumen microbial community. Efforts to elucidate its cellulolytic machinery have resulted in the proposal of numerous models which involve cell-surface attachment via a combination of cellulose-binding fibro-slime proteins and pili, the production of cellulolytic vesicles, and the entry of cellulose fibers into the periplasmic space. Here, we used a combination of RNA-sequencing, proteomics, and transmission electron microscopy (TEM to further clarify the cellulolytic mechanism of F. succinogenes. Our RNAsequence analysis shows that genes encoding type II and III secretion systems, fibro-slime proteins, and pili are differentially expressed on cellulose, relative to glucose. A subcellular fractionation of cells grown on cellulose revealed that carbohydrate active enzymes associated with cellulose deconstruction and fibro-slime proteins were greater in the extracellular medium, as compared to the periplasm and outer membrane fractions. TEMs of samples harvested at mid-exponential and stationary phases of growth on cellulose and glucose showed the presence of grooves in the cellulose between the bacterial cells and substrate, suggesting enzymes work extracellularly for cellulose degradation. Membrane vesicles were only observed in stationary phase cultures grown on cellulose. These results provide evidence that F. succinogenes attaches to cellulose fibers using fibro-slime and pili, produces cellulases, such as endoglucanases, that are secreted extracellularly using type II and III secretion systems, and degrades the cellulose into cellodextrins that are then imported back into the periplasm for further digestion by β-glucanases and other cellulases. 364. Evaluating Models of Cellulose Degradation by Fibrobacter succinogenes S85. Science.gov (United States) Burnet, Meagan C; Dohnalkova, Alice C; Neumann, Anthony P; Lipton, Mary S; Smith, Richard D; Suen, Garret; Callister, Stephen J 2015-01-01 Fibrobacter succinogenes S85 is an anaerobic non-cellulosome utilizing cellulolytic bacterium originally isolated from the cow rumen microbial community. Efforts to elucidate its cellulolytic machinery have resulted in the proposal of numerous models which involve cell-surface attachment via a combination of cellulose-binding fibroslime proteins and pili, the production of cellulolytic vesicles, and the entry of cellulose fibers into the periplasmic space. Here, we used a combination of RNA-sequencing, proteomics, and transmission electron microscopy (TEM) to further clarify the cellulolytic mechanism of F. succinogenes. Our RNA-sequence analysis shows that genes encoding type II and III secretion systems, fibro-slime proteins, and pili are differentially expressed on cellulose, relative to glucose. A subcellular fractionation of cells grown on cellulose revealed that carbohydrate active enzymes associated with cellulose deconstruction and fibro-slime proteins were greater in the extracellular medium, as compared to the periplasm and outer membrane fractions. TEMs of samples harvested at mid-exponential and stationary phases of growth on cellulose and glucose showed the presence of grooves in the cellulose between the bacterial cells and substrate, suggesting enzymes work extracellularly for cellulose degradation. Membrane vesicles were only observed in stationary phase cultures grown on cellulose. These results provide evidence that F. succinogenes attaches to cellulose fibers using fibroslime and pili, produces cellulases, such as endoglucanases, that are secreted extracellularly using type II and III secretion systems, and degrades the cellulose into cellodextrins that are then imported back into the periplasm for further digestion by β-glucanases and other cellulases. 365. Evaluating Models of Cellulose Degradation by Fibrobacter succinogenes S85 Science.gov (United States) Burnet, Meagan C.; Dohnalkova, Alice C.; Neumann, Anthony P.; Lipton, Mary S.; Smith, Richard D.; Suen, Garret; Callister, Stephen J. 2015-01-01 Fibrobacter succinogenes S85 is an anaerobic non-cellulosome utilizing cellulolytic bacterium originally isolated from the cow rumen microbial community. Efforts to elucidate its cellulolytic machinery have resulted in the proposal of numerous models which involve cell-surface attachment via a combination of cellulose-binding fibroslime proteins and pili, the production of cellulolytic vesicles, and the entry of cellulose fibers into the periplasmic space. Here, we used a combination of RNA-sequencing, proteomics, and transmission electron microscopy (TEM) to further clarify the cellulolytic mechanism of F. succinogenes. Our RNA-sequence analysis shows that genes encoding type II and III secretion systems, fibro-slime proteins, and pili are differentially expressed on cellulose, relative to glucose. A subcellular fractionation of cells grown on cellulose revealed that carbohydrate active enzymes associated with cellulose deconstruction and fibro-slime proteins were greater in the extracellular medium, as compared to the periplasm and outer membrane fractions. TEMs of samples harvested at mid-exponential and stationary phases of growth on cellulose and glucose showed the presence of grooves in the cellulose between the bacterial cells and substrate, suggesting enzymes work extracellularly for cellulose degradation. Membrane vesicles were only observed in stationary phase cultures grown on cellulose. These results provide evidence that F. succinogenes attaches to cellulose fibers using fibroslime and pili, produces cellulases, such as endoglucanases, that are secreted extracellularly using type II and III secretion systems, and degrades the cellulose into cellodextrins that are then imported back into the periplasm for further digestion by β-glucanases and other cellulases. PMID:26629814 366. Manufacture of cellulose nanocrystals by cation exchange resin-catalyzed hydrolysis of cellulose. Science.gov (United States) Tang, Li-rong; Huang, Biao; Ou, Wen; Chen, Xue-rong; Chen, Yan-dan 2011-12-01 Cellulose nanocrystals (CNC) were prepared from microcrystalline cellulose (MCC) by hydrolysis with cation exchange resin (NKC-9) or 64% sulfuric acid. The cation exchange resin hydrolysis parameters were optimized by using the Box-Behnken design and response surface methodology. An optimum yield (50.04%) was achieved at a ratio of resin to MCC (w/w) of 10, a temperature of 48 °C and a reaction time of 189 min. Electron microscopy (EM) showed that the diameter of CNCs was about 1040 nm, and the length was 100-400 nm. Regular short rod-like CNCs were obtained by sulfuric acid hydrolysis, while long and thin crystals of cellulose were obtained with the cation exchange resin. X-ray diffraction (XRD) showed that, compared with MCC, the crystallinity of H2SO4-CNC and resin-CNC increased from 72.25% to 77.29% and 84.26%, respectively. The research shows that cation exchange resin-catalyzed hydrolysis of cellulose could be an excellent method for manufacturing of CNC in an environmental-friendly way. Copyright © 2011 Elsevier Ltd. All rights reserved. 367. Composite edible films based on hydroxypropyl methyl cellulose reinforced with microcrystalline cellulose nanoparticles Science.gov (United States) It has been stated that hydroxypropyl methyl cellulose (HPMC) based films have promising applications in the food industry because of their environmental appeal, low cost, flexibility and transparency. Nevertheless, their mechanical and moisture barrier properties should be improved. The aim of th... 368. SULFUR DIOXIDE AND AMMONIA GAS REDUCTION USING COCONUT CELLULOSE AND ACETYLATED CELLULOSE Directory of Open Access Journals (Sweden) SURJANI WONORAHARDJO 2016-07-01 Full Text Available Some adsorbent materials were employed to reduce ammonia and carbon dioxide gases. Cellulose materials from nata de coco and grated coconut meat were packed in a column to be used as gas adsorbent. The effect of surface modification of cellulose by acetylation in order to enhance the sorption ability and capacity was also studied. Another factor that was tested was the column length. The characteristics of cellulose materials were done by electron microscopy, infrared spectroscopy, and physical parameters such as water and ash contents as well as iodine sorption ability. The amount of ammonia and sulfur dioxide gases absorbed by the materials were analyzed by visible spectroscopy. The results showed that the cellulose material can be good adsorbent for basic gas like ammonia as well as acidic sulfur dioxide gases. Acetylation as a method of surface modification gave the proof of better sorption for both gases but was greater for ammonia. However, the column length gave greater impact in ammonia compared to sulfur dioxide. This study provides a better explanation of dynamics at surfaces, in the search for better adsorbents. 369. Uniaxially aligned electrospun all-cellulose nanocomposite nanofibers reinforced with cellulose nanocrystals: scaffold for tissue engineering. Science.gov (United States) He, Xu; Xiao, Qiang; Lu, Canhui; Wang, Yaru; Zhang, Xiaofang; Zhao, Jiangqi; Zhang, Wei; Zhang, Ximu; Deng, Yulin 2014-02-10 Uniaxially aligned cellulose nanofibers with well oriented cellulose nanocrystals (CNCs) embedded were fabricated via electrospinning using a rotating drum as the collector. Scanning electron microscope (SEM) images indicated that most cellulose nanofibers were uniaxially aligned. The incorporation of CNCs into the spinning dope resulted in more uniform morphology of the electrospun cellulose/CNCs nanocomposite nanofibers (ECCNN). Polarized light microscope (PLM) and transmission electron microscope (TEM) showed that CNCs dispersed well in ECCNN nonwovens and achieved considerable orientation along the long axis direction. This unique hierarchical microstructure of ECCNN nonwovens gave rise to remarkable enhancement of their physical properties. By incorporating 20% loading (in weight) of CNCs, the tensile strength and elastic modulus of ECCNN along the fiber alignment direction were increased by 101.7 and 171.6%, respectively. Their thermal stability was significantly improved as well. In addition, the ECCNN nonwovens were assessed as potential scaffold materials for tissue engineering. It was elucidated from MTT tests that the ECCNN were essentially nontoxic to human cells. Cell culture experiments demonstrated that cells could proliferate rapidly not only on the surface but also deep inside the ECCNN. More importantly, the aligned nanofibers of ECCNN exhibited a strong effect on directing cellular organization. This feature made the scaffold particularly useful for various artificial tissues or organs, such as blood vessel, tendon, nerve, and so on, in which cell orientation was crucial for their performance. 370. Chemical modification of cellulose extracted from sugarcane bagasse: Preparation of hydroxyethyl cellulose Directory of Open Access Journals (Sweden) E.S. Abdel-Halim 2014-07-01 Full Text Available Cellulose was extracted from sugarcane bagasse by alkaline extraction with sodium hydroxide followed by delignification/bleaching using sodium chlorite/hexamethylenetetramine system. Factors affecting extraction process, including sodium hydroxide concentration, hexamethylenetetramine concentration and temperature were studied and optimum conditions for alkaline extraction were found to be boiling finely ground bagasse under reflux in 1 N sodium hydroxide solution and then carrying out the delignification/bleaching treatment at 95 °C using 5 g/l sodium chlorite together with 0.02 g/l hexamethylenetetramine. The extracted cellulose was used in the preparation of hydroxyethyl cellulose through reaction with ethylene oxide in alkaline medium. Factors affecting the hydroxyethylation reaction, like sodium hydroxide concentration during the alkali formation step, ethylene oxide concentration, reaction temperature and reaction duration were studied. Optimum conditions for hydroxyethylation reaction were using 20% NaOH solution and 200% ethylene oxide (based on weight of cellulose, carrying out the reaction at 100 °C for 60 min. 371. Microfibrillated Cellulose Based Ink for Eco-Sustainable Screen Printed Flexible Electrodes in Lithium Ion Batteries National Research Council Canada - National Science Library Oussama El Baradai Davide Beneventi Fannie Alloin Roberta Bongiovanni Nadege Bruas-Reverdy Yann Bultel Didier Chaussy 2016-01-01 Free organic solvent ink containing graphite, carboxymethyl cellulose and microfibrillated cellulose as active material, dispersing and binder, respectively, has been formulated to produce flexible... 372. Atomic-scale modeling of cellulose nanocrystals Science.gov (United States) Wu, Xiawa Cellulose nanocrystals (CNCs), the most abundant nanomaterials in nature, are recognized as one of the most promising candidates to meet the growing demand of green, bio-degradable and sustainable nanomaterials for future applications. CNCs draw significant interest due to their high axial elasticity and low density-elasticity ratio, both of which are extensively researched over the years. In spite of the great potential of CNCs as functional nanoparticles for nanocomposite materials, a fundamental understanding of CNC properties and their role in composite property enhancement is not available. In this work, CNCs are studied using molecular dynamics simulation method to predict their material' behaviors in the nanoscale. (a) Mechanical properties include tensile deformation in the elastic and plastic regions using molecular mechanics, molecular dynamics and nanoindentation methods. This allows comparisons between the methods and closer connectivity to experimental measurement techniques. The elastic moduli in the axial and transverse directions are obtained and the results are found to be in good agreement with previous research. The ultimate properties in plastic deformation are reported for the first time and failure mechanism are analyzed in details. (b) The thermal expansion of CNC crystals and films are studied. It is proposed that CNC film thermal expansion is due primarily to single crystal expansion and CNC-CNC interfacial motion. The relative contributions of inter- and intra-crystal responses to heating are explored. (c) Friction at cellulose-CNCs and diamond-CNCs interfaces is studied. The effects of sliding velocity, normal load, and relative angle between sliding surfaces are predicted. The Cellulose-CNC model is analyzed in terms of hydrogen bonding effect, and the diamond-CNC model compliments some of the discussion of the previous model. In summary, CNC's material properties and molecular models are both studied in this research, contributing to 373. Mineralization of cellulose in frozen boreal soils Science.gov (United States) Oquist, Mats G.; Segura, Javier; Sparrman, Tobias; Nilsson, Mats; Schleucher, Jurgen 2015-04-01 Soils of high-latitude ecosystems store a large fraction of the global soil carbon. In boreal forests, the microbial mineralization of soil organic matter (SOM) during winter can affect the ecosystems net carbon balance. Recent research has shown that microorganisms in the organic surface layer of boreal forest soil can mineralize and grow on simple, soluble monomeric substrates under frozen conditions. However, any substantial impacts of microbial activity in frozen soils on long-term soil carbon balances ultimately depends on whether soil microorganisms can utilize and grow the more complex, polymeric constituents of SOM. In order to evaluate the potential for soil microorganisms to metabolize carbon polymers at low temperatures, we incubated boreal forest soil samples amended with [13C]-cellulose and studied the microbial catabolic and anabolic utilization of the substrate under frozen and unfrozen conditions (-4 and +4°C). Freezing of the soil markedly reduced microbial utilization of the cellulose. The [13C]-CO2 production rate in the samples at +4°C were 0.52 mg CO2 SOM -1 day-1 while rates in the frozen samples (-4°C) were 0.01 mg CO2 SOM -1 day-1. However, newly synthetized [13C]-enriched cell membrane lipids, PLFAs, were detected in soil samples incubated both above and below freezing, confirming that cellulose can sustain also anabolic activity of the microbial populations under frozen conditions. The reduced metabolic rates induced by freezing indicate constraints on exoenzymatic activity, as well as substrate diffusion rates that we can attribute to reduced liquid water content of the frozen soil. We conclude that the microbial population in boreal forest soil has the capacity to metabolize, and grow, on polymeric substrates at temperatures below zero, which involves maintaining exoenzymatic activity in frozen soils. This capacity manifests the importance of SOM mineralization during the winter season and its importance for the net carbon balance of 374. A Sorption Hysteresis Model For Cellulosic Materials DEFF Research Database (Denmark) Frandsen, Henrik Lund; Damkilde, Lars 2006-01-01 The equilibrium concentration of adsorbed water in cellulosic materials is dependent on the history of the variations of vapor pressure in the ambient air, i.e. sorption hysteresis. Existing models to describe this phenomenon such as the independent domain theory have numerical drawbacks and....../or imply accounting for the entire history variations of every material point. This paper presents a sorption hysteresis model based on a state formulation and expressed in closed-form solutions, which makes it suitable for implementation into a numerical method.... 375. Mechanical Properties of Cellulose Microfiber Reinforced Polyolefin Science.gov (United States) Kobayashi, Satoshi; Yamada, Hiroyuki Cellulose microfiber (CeF) has been expected as a reinforcement of polymer because of its high modulus and strength and lower cost. In the present study, mechanical properties of CeF/polyolefin were investigated. Tensile modulus increased with increasing CeF content. On the other hand, tensile strength decreased. Fatigue properties were also investigated with acoustic emission measurement. Stiffness of the composites gradually decreased with loading. Drastic decrease in stiffness was observed just before the final fracture. Based on the Mori-Tanaka's theory, the method to calculate modulus of CeF were proposed to evaluate dispersion of CeF. 376. Temperature responsive hydroxypropyl cellulose for encapsulation Energy Technology Data Exchange (ETDEWEB) Heitfeld, Kevin A.; Guo, Tingtai; Yang, George; Schaefer, Dale W. (UCIN) 2009-08-26 This work focuses on the use of temperature responsive gels (TRGs) (polymeric hydrogels with a large temperature-dependent change in volume) for flavor retention at cooking temperatures. Specifically, we have studied a gel with a lower critical solution temperature (LCST) that swells at low temperatures and collapses at high temperatures. In the collapsed state, the polymer acts as a transport barrier, keeping the volatile flavors inside. We have successfully synthesized a cellulose gel that exhibits this volume change and have encapsulated an oil phase inside the gel. The flavor-loaded encapsulated oil exhibited an increased release time when compared to similar gelatin capsules. 377. Understanding plant cellulose synthases through a comprehensive investigation of the cellulose synthase family sequences. Directory of Open Access Journals (Sweden) Andrew eCarroll 2011-03-01 Full Text Available The development of cellulose as an organizing structure in the plant cell wall was a key event in both the initial colonization and the subsequent domination of the terrestrial ecosystem by vascular plants. A wealth of experimental data has demonstrated the complicated genetic interactions required to form the large synthetic complex that synthesizes cellulose. However, these results are lacking an extensive analysis of the evolution, specialization, and regulation of the proteins that compose this complex. Here we perform an in-depth analysis of the sequences in the cellulose synthase (CesA family. We investigate the phylogeny of the CesA family, with emphasis on evolutionary specialization. We define specialized subfamilies and identify the class-specific regions within the CesA sequence that may explain this specialization. We investigate changes in regulation of CesAs by looking at the conservation of proposed phosphorylation sites. We investigate the conservation of sites where mutations have been documented that impair cellulose synthase function, and compare these sites to those observed in the closest cellulose synthase-like (Csl families to better understand what regions may separate the CesAs from other Csls. Finally we identify two positions with strong conservation of the aromatic trait, but lacking conservation of amino acid identity, which may represent residues important for positioning the sugar substrate for catalysis. These analyses provide useful tools for understanding characterized mutations and post-translational modifications, and for informing further experiments to probe CesA assembly, regulation, and function through site-directed mutagenesis or domain swapping experiments. 378. Determination of cellulose I crystallinity by FT-Raman spectroscopy Science.gov (United States) Umesh P. Agarwal; Richard S. Reiner; Sally A. Ralph 2009-01-01 Two new methods based on FT-Raman spectroscopy, one simple, based on band intensity ratio, and the other, using a partial least-squares (PLS) regression model, are proposed to determine cellulose I crystallinity. In the simple method, crystallinity in semicrystalline cellulose I samples was determined based on univariate regression that was first developed using the... 379. CELLULOSE EXTRACTION FROM PALM KERNEL CAKE USING LIQUID PHASE OXIDATION Directory of Open Access Journals (Sweden) FARM YAN YAN 2009-03-01 Full Text Available Cellulose is widely used in many aspect and industries such as food industry, pharmaceutical, paint, polymers, and many more. Due to the increasing demand in the market, studies and work to produce cellulose are still rapidly developing. In this work, liquid phase oxidation was used to extract cellulose from palm kernel cake to separate hemicellulose, cellulose and lignin. The method is basically a two-step process. Palm kernel cake was pretreated in hot water at 180°C and

followed by liquid oxidation process with 30% H2O2 at 60°C at atmospheric pressure. The process parameters are hot water treatment time, ratio of palm kernel cake to H2O2, liquid oxidation reaction temperature and time. Analysis of the process parameters on production cellulose from palm kernel cake was performed by using Response Surface Methodology. The recovered cellulose was further characterized by Fourier Transform Infrared (FTIR. Through the hot water treatment, hemicellulose in the palm kernel cake was successfully recovered as saccharides and thus leaving lignin and cellulose. Lignin was converted to water soluble compounds in liquid oxidation step which contains small molecular weight fatty acid as HCOOH and CH3COOH and almost pure cellulose was recovered. 380. Dual morphology (fibres and particles) cellulosic filler for WPC materials Energy Technology Data Exchange (ETDEWEB) Valente, Marco, E-mail: [email protected]; Tirillò, Jacopo; Quitadamo, Alessia, E-mail: [email protected] [University of Rome La Sapienza Dep. of Chemical and Material Engineering (Italy); Santulli, Carlo [University of Camerino, School of Architecture and Design (Italy) 2016-05-18 Wood-plastic composites (WPC) were fabricated by using a polyethylene (PE) matrix and filling it with wood flour in the amount of 30 wt.%, and compared with the same composites with further amount of 10 wt.% of cellulosic recycled fibres added. The materials were produced by turbomixing and subsequent moulding under pressure. Mechanical properties of both WPC and WPC with cellulosic recycled fibres were evaluated through mechanical and physical-chemical tests. Tensile tests clarified that a moderate reduction is strength is observed with the bare introduction of wood flour with respect to the neat PE matrix, whilst some recovery is offered by the addition of recycled cellulose fibres. Even more promisingly, the elastic modulus of PE matrix is substantially improved by the addition of wood flour (around 8% on average) and much more so with the further addition of recycled cellulose (around 20% on average). The fracture surfaces from the tensile test were analysed by scanning electron microscope (SEM) indicating a reduction in microporosity as an effect of added cellulose. The water absorption test and the hardness measure (Shore D) were also performed. SEM analysis underlined the weak interface between both wood particle and cellulosic recycled fibres and matrix. The water absorption test showed a higher mass variation for pure WPC than WPC with cellulosic recycled fibres. The hardness measurement showed that the presence of cellulosic recycled fibres improves both superficial hardness of the composite and temperature resistance. « 17 18 19 20 21 » « 18 19 20 21 22 » 381. Dual morphology (fibres and particles) cellulosic filler for WPC materials Science.gov (United States) Valente, Marco; Tirillò, Jacopo; Quitadamo, Alessia; Santulli, Carlo 2016-05-01 Wood-plastic composites (WPC) were fabricated by using a polyethylene (PE) matrix and filling it with wood flour in the amount of 30 wt.%, and compared with the same composites with further amount of 10 wt.% of cellulosic recycled fibres added. The materials were produced by turbomixing and subsequent moulding under pressure. Mechanical properties of both WPC and WPC with cellulosic recycled fibres were evaluated through mechanical and physical-chemical tests. Tensile tests clarified that a moderate reduction is strength is observed with the bare introduction of wood flour with respect to the neat PE matrix, whilst some recovery is offered by the addition of recycled cellulose fibres. Even more promisingly, the elastic modulus of PE matrix is substantially improved by the addition of wood flour (around 8% on average) and much more so with the further addition of recycled cellulose (around 20% on average). The fracture surfaces from the tensile test were analysed by scanning electron microscope (SEM) indicating a reduction in microporosity as an effect of added cellulose. The water absorption test and the hardness measure (Shore D) were also performed. SEM analysis underlined the weak interface between both wood particle and cellulosic recycled fibres and matrix. The water absorption test showed a higher mass variation for pure WPC than WPC with cellulosic recycled fibres. The hardness measurement showed that the presence of cellulosic recycled fibres improves both superficial hardness of the composite and temperature resistance. 382. Life Cycle Assessment of man-made cellulose fibres NARCIS (Netherlands) Shen, L.; Patel, M.K. 2010-01-01 The production of textile materials has undergone dramatic changes in the last century. Man-made cellulose fibres have played an important role for more than 70 years. Today, the man-made cellulose fibre industry is the worldwide second largest biorefinery (next to the paper industry). In the last 383. Cellulose: A review as natural, modified and activated carbon adsorbent. Science.gov (United States) Suhas; Gupta, V K; Carrott, P J M; Singh, Randhir; Chaudhary, Monika; Kushwaha, Sarita 2016-09-01 Cellulose is a biodegradable, renewable, non-meltable polymer which is insoluble in most solvents due to hydrogen bonding and crystallinity. Natural cellulose shows lower adsorption capacity as compared to modified cellulose and its capacity can be enhanced by modification usually by chemicals. This review focuses on the utilization of cellulose as an adsorbent in natural/modified form or as a precursor for activated carbon (AC) for adsorbing substances from water. The literature revealed that cellulose can be a promising precursor for production of activated carbon with appreciable surface area (∼1300m(2)g(-1)) and total pore volume (∼0.6cm(3)g(-1)) and the surface area and pore volume varies with the cellulose content. Finally, the purpose of review is to report a few controversies and unresolved questions concerning the preparation/properties of ACs from cellulose and to make aware to readers that there is still considerable scope for future development, characterization and utilization of ACs from cellulose. 384. Methods of detection using a cellulose binding domain fusion product Energy Technology Data Exchange (ETDEWEB) Shoseyov, Oded (Shimshon, IL); Shpiegl, Itai (North Gallilea, IL); Goldstein, Marc A. (Davis, CA); Doi, Roy H. (Davis, CA) 1999-01-01 A cellulose binding domain (CBD) having a high affinity for crystalline cellulose and chitin is disclosed, along with methods for the molecular cloning and recombinant production thereof. Fusion products comprising the CBD and a second protein are likewise described. A wide range of applications are contemplated for both the CBD and the fusion products, including drug delivery, affinity separations, and diagnostic techniques. 385. Life Cycle Assessment of man-made cellulose fibres NARCIS (Netherlands) Shen, L.; Patel, M.K. 2010-01-01 The production of textile materials has undergone dramatic changes in the last century. Man-made cellulose fibres have played an important role for more than 70 years. Today, the man-made cellulose fibre industry is the worldwide second largest biorefinery (next to the paper industry). In the last f 386. Environmental impact assessment of man-made cellulose fibres NARCIS (Netherlands) Shen, L.; Worrell, E.; Patel, M.K. 2010-01-01 Man-made cellulose fibres have played an important role in the production of textile products for more than 70 years. The purpose of this study is to assess the environmental impact of man-made cellulose fibres. Life cycle assessment (LCA) was conducted for three types of fibres (i.e. Viscose, Modal 387. Methods of use of cellulose binding domain proteins Science.gov (United States) Shoseyov, Oded; Shpiegl, Itai; Goldstein, Marc A.; Doi, Roy H. 1997-01-01 A cellulose binding domain (CBD) having a high affinity for crystalline cellulose and chitin is disclosed, along with methods for the molecular cloning and recombinant production thereof. Fusion products comprising the CBD and a second protein are likewise described. A wide range of applications are contemplated for both the CBD and the fusion products, including drug delivery, affinity separations, and diagnostic techniques. 388. Mechanization of Continuous Production of Powdered Cellulose Technology Science.gov (United States) Prosvirnikov, D. B.; Safin, R. G.; Akhmetshin, I. R.; Taimarov, M. A.; Timerbaev, N. F. 2017-07-01 The article presents the mechanization of the process for obtaining powdered cellulose using the technology of steam explosion treatment of lignocellulosic material. The presented unit combines the methods of steam explosion treatment and acid hydrolysis of cellulose-containing raw materials. 389. Cellulose-Lignin interactions during slow and fast pyrolysis NARCIS (Netherlands) Hilbers, T.J.; Wang, Z.; Pecha, B.; Westerhof, R.J.M.; Kersten, S.R.A.; Pelaez-Samaniego, M.R.; Garcia-Perez, M. 2015-01-01 The interactions between lignin and cellulose during the slow pyrolysis of their blends were studied by means of Thermogravimetric Analysis (TGA) and Scanning Electron Microscopy (SEM). Fast pyrolysis was studied using Pyrolysis-Gas Chromatography/Mass Spectroscopy (Py–GC/MS). Crystalline cellulose 390. Life Cycle Assessment of man-made cellulose fibres NARCIS (Netherlands) Shen, L.|info:eu-repo/dai/nl/310872022; Patel, M.K.|info:eu-repo/dai/nl/18988097X 2010-01-01 The production of textile materials has undergone dramatic changes in the last century. Man-made cellulose fibres have played an important role for more than 70 years. Today, the man-made cellulose fibre industry is the worldwide second largest biorefinery (next to the paper industry). In the last f 391. Environmental impact assessment of man-made cellulose fibres NARCIS (Netherlands) Shen, L.; Worrell, E.; Patel, M.K. 2010-01-01 Man-made cellulose fibres have played an important role in the production of textile products for more than 70 years. The purpose of this study is to assess the environmental impact of man-made cellulose fibres. Life cycle assessment (LCA) was conducted for three types of fibres (i.e. Viscose, Modal 392. Development and Characterization of Cellulose/clay Nanocomposites Science.gov (United States) Cotton is the most important textile fiber for apparel use and is preferred to synthetic fibers for reasons such as comfort and feel. A major drawback of cellulosic fibers is flammability. The development of cellulose/clay nanocomposites for use as flame retardant materials based on cotton is repo... 393. Single Molecule Study of Cellulase Hydrolysis of Crystalline Cellulose Energy Technology Data Exchange (ETDEWEB) Liu, Y.-S.; Luo, Y.; Baker, J. O.; Zeng, Y.; Himmel, M. E.; Smith, S.; Ding, S.-Y. 2009-12-01 This report seeks to elucidate the role of cellobiohydrolase-I (CBH I) in the hydrolysis of crystalline cellulose. A single-molecule approach uses various imaging techniques to investigate the surface structure of crystalline cellulose and changes made in the structure by CBH I. 394. Endurance of high molecular weight carboxymethyl cellulose in corrosive environments Science.gov (United States) Murodov, M. M.; Rahmanberdiev, G. R.; Khalikov, M. M.; Egamberdiev, E. A.; Negmatova, K. C.; Saidov, M. M.; Mahmudova, N. 2012-07-01 Lignin obtained from the waste cooking liquor, formed after soda pulping process, is used as an inhibitor of NaCMC thermo oxidative degradation in presence of in extreme conditions during drilling oil wells. In this paper the schematic process of obtaining NaCMC by the principle of "monoapparat" on the basis of cellulose produced by non-wood cellulose materials is presented. 395. Characterization of cellulose based sponges for wound dressings NARCIS (Netherlands) Gustaite, S.; Kazlauske, J.; Bobokalonov, J.; Perni, S.; Dutschk, Victoria; Liesiene, J.; Prokopovich, P. 2015-01-01 Cellulose based sponges were developed by freeze-drying of regenerated cellulose gels and characterizedas a potential wound dressing. Morphological characteristics were analyzed by means of micro-computedtomography. The results showed that the porosity of the sponges reached 75%, the pores were 396. Characterization of cellulose based sponges for wound dressings NARCIS (Netherlands) Gustaite, S.; Kazlauske, J.; Bobokalonov, J.; Perni, S.; Dutschk, V.; Liesiene, J.; Prokopovich, P. 2015-01-01 Cellulose based sponges were developed by freeze-drying of regenerated cellulose gels and characterizedas a potential wound dressing. Morphological characteristics were analyzed by means of micro-computedtomography. The results showed that the porosity of the sponges reached 75%, the pores were inte 397. Cellulose synthesizing Complexes in Vascular Plants andProcaryotes Energy Technology Data Exchange (ETDEWEB) Brown, Richard M, Jr; Saxena, Inder Mohan 2009-07-07 Continuing the work initiated under DE-FG03-94ER20145, the following major accomplishments were achieved under DE-FG02-03ER15396 from 2003-2007: (a) we purified the acsD gene product of the Acetobacter cellulose synthase operon as well as transferred the CesA cellulose gene from Gossypium into E. coli in an attempt to crystallize this protein for x-ray diffraction structural analysis; however, crystallization attempts proved unsuccessful; (b) the Acetobacter cellulose synthase operon was successfully incorporated into Synechococcus, a cyanobacterium2; (c) this operon in Synechococcus was functionally expressed; (d) we successfully immunolabeled Vigna cellulose and callose synthase components and mapped their distribution before and after wounding; (e) we developed a novel method to produce replicas of cellulose synthases in tobacco BY-2 cells, and we demonstrated the cytoplasmic domain of the rosette TC; (f) from the moss Physcomitrella, we isolated two full-length cDNA sequences of cellulose synthase (PpCesA1 and PpCesA2) and attempted to obtain full genomic DNA sequences; (g) we examined the detailed molecular structure of a new form of non-crystalline cellulose known as nematic ordered cellulose (=NOC)3. 398. Molecular weights of cellulose nitrates by osmotic pressure measurements Directory of Open Access Journals (Sweden) dr. V. Subramanyam 1950-04-01 Full Text Available It is well-known that nitro celluloses are employed for a variety of purposes. Broadly  nitrocellulose with relatively high nitrogen content are used in propellant and explosive manufacture nitrocelluloses  with lower nitrogen content find application in celluloid, in the lacquer industry, in cellulose paints, etc. 399. Carbon-supported base metal nanoparticles : Cellulose at work NARCIS (Netherlands) Hoekstra, Jacco; Versluijs-Helder, Marjan; Vlietstra, Edward J.; Geus, John W.; Jenneskens, Leonardus W. 2015-01-01 Pyrolysis of base metal salt loaded microcrystalline cellulose spheres gives a facile access to carbon-supported base metal nanoparticles, which have been characterized with temperature-dependent XRD, SEM, TEM, ICP-MS and elemental analysis. The role of cellulose is multifaceted: 1) it facilitates a 400. A actividade FÃsica e Desportiva e a Terceira Idade. Estudo Centrado no Concelho de Celorico da Beira Directory of Open Access Journals (Sweden) C. Silva 2016-02-01 No que se refere à s actividades fÃsicas que os idosos gostariam de praticar verifica-se que os jogos tradicionais, os percursos pedestres, os exercÃcios nas máquinas (bicicleta e tapete rolante e as actividades aquáticas são as mais desejadas.

« 18 19 20 21 22 » « 19 20 21 22 23 » 401. Actividad fÃsica en pacientes ambulatorios con diabetes mellitus 2 de un Hospital Nacional del Perú Directory of Open Access Journals (Sweden) Ana Josefina Manzaneda Full Text Available Con el objetivo de determinar el nivel de actividad fÃsica que realizan los pacientes ambulatorios con diabetes mellitus tipo 2 (DM 2 que acuden a un Hospital Nacional de Lima, Perú se incluyó a 120 pacientes en quienes se aplicó el cuestionario internacional de actividad fÃsica IPAQ. El 66% fueron mujeres, la edad media fue 61,6 años, el 70% presentó mal control glicémico. El 20% de pacientes calificaba como inactivo, 68% con mÃnima actividad y 12% con actividad fÃsica adecuada. No se halló relación entre actividad fÃsica, tiempo de enfermedad, control glicémico, ni el Ãndice de masa corporal. La edad se asoció negativamente con la actividad fÃsica. Se concluye que existen bajos niveles de actividad fÃsica en pacientes con DM 2 y esta no se enfoca en actividades de ocio que proveen beneficios a la salud 402. Un algoritmo para la realización de grafos con las actividades en los arcos -grafos pertDirectory of Open Access Journals (Sweden) Angel M. Gento Municio 2005-01-01 Full Text Available El problema de dibujar redes con las actividades en los arcos (redes PERT es un problema NP-completo. Diferentes autores (Syslo, 1984 han establecido lÃmites al mismo. En primer lugar debemos diferenciar entre redes con actividades en los nudos y redes con actividades en los arcos. Si las actividades están en los nudos, el dibujo de la red es muy fácil, pero cuando las actividades están en los arcos, generalmente es necesaria la utilización de actividades ficticias para mantener de forma correcta las relaciones entre las actividades. En este artÃculo se propone un sencillo y didáctico algoritmo para el caso de un pequeño número de nodos donde es necesario un algoritmo intuitivo. En el algoritmo se definen cuatro tipos diferentes de nodos que pueden aparecer en el grafo, permitiéndonos identificar las actividades ficticias tal y como se muestra en un ejemplo. 403. Environmentally friendly cellulose-based polyelectrolytes in wastewater treatment. Science.gov (United States) Grenda, Kinga; Arnold, Julien; Gamelas, José A F; Rasteiro, Maria G 2017-09-01 Natural-based polyelectrolytes (PELs), with all the advantages coming from being produced from renewable and biodegradable sources, are a potential solution for the removal of dyes from wastewater. In this work, surplus Eucalyptus bleached cellulose fibres from a paper mill were modified to increase the charge and solubility of cellulose. First, reactive aldehyde groups were introduced in the cellulose backbone by periodate oxidation of cellulose. Further modification with alkylammonium produced positively charged cellulose-based PELs. The final products were characterized by several analytical techniques. The PEL with the highest substitution degree of cationic groups was evaluated for its performance in decolouration processes, bentonite being used as aid. This was found to be effective for colour removal of either anionic or cationic dyes. Bio-PELs can thus be considered as very favourable eco-friendly flocculation agents for decolouration of harsh effluents from several industries, considering their biodegradable nature and thus the ability to produce less sludge. 404. Production of ethanol from cellulose using Clostridum thermocellum Energy Technology Data Exchange (ETDEWEB) Zertuche, L.; Zall, R.R. 1982-01-01 Clostridium thermocellum was used to produce ethanol from cellulose in a continuous system. Batch fermentations were first performed to observe the effects of buffers and agitation on generation time and ethanol production. Continuous fermentations were carried out at 60/sup 0/C and pH 7 using pure cellulose as the limiting substrate. The maximum ethanol concentrations produced with 1.5 and 3% cellulose fermenting liquid were 0.3 and 0.9% respectively. The yield of ethanol was about 0.3 grams per gram of cellulose consumed. While the continuous fermentaion of cellulose with Clostridium thermocellum appears to be feasible, it may not be economically promising due to the slow growth of the organism. 405. Dissolution of cellulose in ionic liquid: A review Science.gov (United States) Mohd, N.; Draman, S. F. S.; Salleh, M. S. N.; Yusof, N. B. 2017-02-01 Dissolution of cellulose with ionic liquids (IL) and deep eutectic solvent (DES) lets the comprehensive dissolution of cellulose. Basically, cellulose can be dissolved, in some hydrophilic ionic liquids, such as 1-butyl-3-methylimidazolium chloride (BMIMCl) and 1-allyl-3-methylimidazolium chloride (AMIMCl). Chloride based ionic liquids are suitable solvents for cellulose dissolution. Although the ILs is very useful in fine chemical industry, its application in the pharmaceutical and food industry have been very limited due to issues with toxicity, purity, and high cost. Seeing to these limitations, new green alternative solvent which is DES was used. This green solvents, may be definitely treated as the next-generation reagents for more sustainable industrial development. Thus, this review aims to discuss the dissolution of cellulose either with ionic liquids or DES and its application. 406. Titanium dioxide-cellulose hybrid nanocomposite based conductometric glucose biosensor Science.gov (United States) Maniruzzaman, Mohammad; Mahadeva, Suresha K.; Khondoker, Abu Hasan; Kim, Jaehwan 2012-04-01 This paper investigates the feasibility of conductometric glucose biosensor based on glucose oxidase (GOx) immobilized TiO2-cellulose hybrid nanocomposite. TiO2 nanoparticles were blended with cellulose solution prepared by dissolving cotton pulp with lithium chloride/N, N-dimethylacetamide solvent to fabricate TiO2-cellulose hybrid nanocomposite. The enzyme (GOx) was immobilized into this hybrid material by physical adsorption method. The successful immobilization of GOx into TiO2cellulose hybrid nanocomposite via covalent bonding between TiO2 and GOx was confirmed by X-ray photoelectron analysis. The linear response of our propose glucose biosensor is obtained in the range of 1-10mM with correlation coefficient of 0.93. Our study demonstrates TiO2-cellulose hybrid material as a potential candidate for an inexpensive, flexible and disposable glucose biosensor. 407. NANOCOMPOSITES OF POLY(LACTIC ACID REINFORCED WITH CELLULOSE NANOFIBRILS Directory of Open Access Journals (Sweden) Liping Zhang 2010-06-01 Full Text Available A chemo-mechanical method was used to prepare cellulose nanofibrils dispersed uniformly in an organic solvent. Poly(ethylene glycol (PEG 1000 was added to the matrix as a compatibilizer to improve the interfacial interaction between the hydrophobic poly(lactic acid (PLA and the hydrophilic cellulose nanofibrils. The composites obtained by solvent casting methods from N,N-Dimethylacetamide (DMAc were characterized by tensile testing machine, atomic force microscope (AFM, scanning electron microscope (SEM, and Fourier transform infrared spectroscopy (FT-IR. The tensile test results indicated that, by adding PEG to the PLA and the cellulose nanofibrils matrix, the tensile strength and the elongation rate increased by 56.7% and 60%, respectively, compared with the PLA/cellulose nanofibrils composites. The FT-IR analysis successfully showed that PEG improved the intermolecular interaction, which is based on the existence of inter-molecular hydrogen bonding among PLA, PEG, and cellulose nanofibrils. 408. In-situ glyoxalization during biosynthesis of bacterial cellulose. Science.gov (United States) Castro, Cristina; Cordeiro, Nereida; Faria, Marisa; Zuluaga, Robin; Putaux, Jean-Luc; Filpponen, Ilari; Velez, Lina; Rojas, Orlando J; Gañán, Piedad 2015-08-01 A novel method to synthesize highly crosslinked bacterial cellulose (BC) is reported. The glyoxalization is started in-situ, in the culture medium during biosynthesis of cellulose by Gluconacetobacter medellensis bacteria. Strong crosslinked networks were formed in the contact areas between extruded cellulose ribbons by reaction with the glyoxal precursors. The crystalline structure of cellulose was preserved while the acidic component of the surface energy was reduced. As a consequence, its predominant acidic character and the relative contribution of the dispersive component increased, endowing the BC network with a higher hydrophobicity. This route for in-situ crosslinking is expected to facilitate other modifications upon biosynthesis of cellulose ribbons by microorganisms and to engineer the strength and surface energy of their networks. 409. The Solubility of Natural Cellulose After DBD Plasma Treatment Institute of Scientific and Technical Information of China (English) WU Jun; ZENG Fengcai; CHEN Bingqiang 2008-01-01 Natural cellulose was treated by an atmospheric DBD plasma. The solubility of cel-lulose in a diluted alkaline solution after the plasma treatment was investigated. The properties were characterized by X-ray photoelectron spectroscopy (XPS), Fourier-transform infrared spec-troscopy (FTIR) and scanning electron microscopy (SEM). The results indicated that the surface of cellulose treated by the argon DBD plasma was significantly etched, and the relevant force of hy-drogen bonding was decreased. This might be the essential reason for the solubility improvement of natural cellulose in the diluted alkaline solution. Through a comparison of two discharge modes, the atmospheric DBD plasma gun and the parallel plate capacitively coupled DBD plasma, it wasfound that the atmospheric DBD plasma gun was more effective in fragmentizing the cellulose due to its production of a high energy plasma based on its special structure [6] . 410. Molecular-scale investigations of cellulose microstructure during enzymatic hydrolysis. Science.gov (United States) Santa-Maria, Monica; Jeoh, Tina 2010-08-09 Changes in cellulose microstructure have been proposed to occur throughout hydrolysis that impact enzyme access and hydrolysis rates. However, there are very few direct observations of such changes in ongoing reactions. In this study, changes in the microstructure of cellulose are measured by simultaneous confocal and atomic force microscopy and are correlated to hydrolysis extents and quantities of bound enzyme in the reaction. Minimally processed and never-dried cellulose I was hydrolyzed by a purified cellobiohydrolase, Trichoderma reesei Cel7A. Early in the reaction ( approximately 30% hydrolysis), at high hydrolysis rates and high bound cellulase quantities, untwisting of cellulose microfibrils was observed. As the hydrolysis reaction neared completion (>80% hydrolysis), extensively thinned microfibrils (diameters of 3-5 nm) and channels (0.3-0.6 nm deep) along the lengths of the microfibrils were observed. The prominent microstructural changes in cellulose due to cellobiohydrolase action are discussed in the context of the overall hydrolysis reaction. 411. Multifilament cellulose/chitin blend yarn spun from ionic liquids. Science.gov (United States) Mundsinger, Kai; Müller, Alexander; Beyer, Ronald; Hermanutz, Frank; Buchmeiser, Michael R 2015-10-20 Cellulose and chitin, both biopolymers, decompose before reaching their melting points. Therefore, processing these unmodified biopolymers into multifilament yarns is limited to solution chemistry. Especially the processing of chitin into fibers is rather limited to distinctive, often toxic or badly removable solvents often accompanied by chemical de-functionalization to chitosan (degree of acetylation, DA, cellulose/chitin blend fibers using ionic liquids (ILs) as gentle, removable, recyclable and nondeacetylating solvents. Chitin and cellulose are dissolved in ethylmethylimidazolium propionate ([C2mim](+)[OPr](-)) and the obtained one-pot spinning dope is used to produce multifilament fibers by a continuous wet-spinning process. Both the rheology of the corresponding spinning dopes and the structural and physical properties of the obtained fibers have been determined for different biopolymer ratios. With respect to medical or hygienic application, the cellulose/chitin blend fiber show enhanced water retention capacity compared to pure cellulose fibers. 412. Regenerated cellulose/wool blend enhanced biomimetic hydroxyapatite mineralization. Science.gov (United States) Salama, Ahmed; El-Sakhawy, Mohamed 2016-11-01 The current article investigates the effect of bioactive cellulose/wool blend on calcium phosphate biomimetic mineralization. Regenerated cellulose/wool blend was prepared by dissolution-regeneration of neat cellulose and natural wool in 1-butyl-3-methyl imidazolium chloride [Bmim][Cl], as a solvent for the two polymers. Crystalline hydroxyapatite nanofibers with a uniform size, shape and dimension were formed after immersing the bioactive blend in simulated body fluid. The cytotoxicity of cellulose/wool/hydroxyapatite was studied using animal fibroblast baby hamster kidney cells (BHK-21) and the result displayed good cytocompatability. This research work presents a green processing method for the development of novel cellulose/wool/hydroxyapatite hybrid materials for tissue engineering applications. 413. Cellulose destruction under successive thermal and radiation treatment. [Gamma radiation Energy Technology Data Exchange (ETDEWEB) Ershov, B.G.; Komarov, V.B. 1985-02-01 The influence of successive thermal and radiation effect on cellulose is investigated. The samples were ..gamma.. irradiated (/sup 60/Co) with a dose rate of 20 kGy/h (the absorbed doses ranged from 0 to 80 kGy) and heated up to 190 deg C. It is shown that the attainment of the same destruction depth for the heated-up cellulose occurs at noticeably lower absorbed doses than for the cellulose which has not been subjected to thermal treatment. For successive thermal and radiation treatment of cellulose the ratio S=S therm.+Ssub(rad) where S is a number of broken bonds in a macromolecule is correct. The radiation-chemical yield of cellulose destruction is determined to be: G=7.3 +- 0.1 mol/100 eV. 414. Experimental study on cellulose particulate and its composites Science.gov (United States) Srinivasababu, Nadendla 2016-05-01 Anselme Payen has discovered cellulose after conducting rigorous experiments on wood. In this work an attempt is made to reinforce cellulose particulate into polyester matrix from 1.84 - 9.18 wt % and the lamina is manufactured by JMFIL technique. The fabricated lamina is cut into specimens for various tests as per ASTM standards. Tensile strength of 22.61 MPa is achieved at 1.84 % of cellulose content in composites. Then the cellulose composites at 1.89% of reinforcement level showed 55.57 MPa, 1.86 GPa flexural strength, modulus respectively. `C' kind of failure is visualized for all the specimens and volume fractions during impact test. The cellulose particulate is also analyzed for its morphology, size. 415. Physical properties of agave cellulose graft polymethyl methacrylate Energy Technology Data Exchange (ETDEWEB) Rosli, Noor Afizah; Ahmad, Ishak; Abdullah, Ibrahim; Anuar, Farah Hannan [Polymer Research Centre (PORCE), School of Chemical Sciences and Food Technology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 Bangi Selangor (Malaysia) 2013-11-27 The grafting polymerization of methyl methacrylate and Agave cellulose was prepared and their structural analysis and morphology were investigated. The grafting reaction was carried out in an aqueous medium using ceric ammonium nitrate as an initiator. The structural analysis of the graft copolymers was carried out by Fourier transform infrared and X-ray diffraction. The graft copolymers were also characterized by field emission scanning electron microscopy (FESEM). An additional peak at 1732 cm{sup −1} which was attributed to the C=O of ester stretching vibration of poly(methyl methacrylate), appeared in the spectrum of grafted Agave cellulose. A slight decrease of crystallinity index upon grafting was found from 0.74 to 0.68 for cellulose and grafted Agave cellulose, respectively. Another evidence of grafting showed in the FESEM observation, where the surface of the grafted cellulose was found to be roughed than the raw one. 416. Physical properties of agave cellulose graft polymethyl methacrylate Science.gov (United States) Rosli, Noor Afizah; Ahmad, Ishak; Abdullah, Ibrahim; Anuar, Farah Hannan 2013-11-01 The grafting polymerization of methyl methacrylate and Agave cellulose was prepared and their structural analysis and morphology were investigated. The grafting reaction was carried out in an aqueous medium using ceric ammonium nitrate as an initiator. The structural analysis of the graft copolymers was carried out by Fourier transform infrared and X-ray diffraction. The graft copolymers were also characterized by field emission scanning electron microscopy (FESEM). An additional peak at 1732 cm-1 which was attributed to the C=O of ester stretching vibration of poly(methyl methacrylate), appeared in the spectrum of grafted Agave cellulose. A slight decrease of crystallinity index upon grafting was found from 0.74 to 0.68 for cellulose and grafted Agave cellulose, respectively. Another evidence of grafting showed in the FESEM observation, where the surface of the grafted cellulose was found to be roughed than the raw one. 417. Loosening Xyloglucan Accelerates the Enzymatic Degradation of Cellulose in Wood Institute of Scientific and Technical Information of China (English) Rumi Kaida; Tomomi Kaku; Kei'ichi Baba; Masafumi Oyadomari; Takashi Watanabe; Koji Nishida; Toshiji Kanaya; Ziv Shani; Oded Shoseyov; Takahisa Hayashi 2009-01-01 In order to create trees in which cellulose, the most abundant component in biomass, can be enzymatically hydrolyzed highly for the production of bioethanol, we examined the saccharification of xylem from several transgenic poplars, each overexpressing either xyloglucanase, cellulase, xylanase, or galactanase. The level of cellulose degradation achieved by a cellulase preparation was markedly greater in the xylem overexpressing xyloglucanase and much greater in the xylems overexpressing xylanase and cellulase than in the xylem of the wild-type plant. Although a high degree of degradation occurred in all xylems at all loci, the crystalline region of the cellulose microfibrUs was highly degraded in the xylem overexpressing xyloglucanase. Since the complex between microfibrils and xyloglucans could be one region that is particularly resistant to cellulose degradation, loosening xyloglucan could facilitate the enzymatic hydrolysis of cellulose in wood. 418. Overview of Cellulose Nanomaterials, Their Capabilities and Applications Science.gov (United States) Moon, Robert J.; Schueneman, Gregory T.; Simonsen, John

2016-09-01 Cellulose nanomaterials (CNs) are a new class of cellulose particles with properties and functionalities distinct from molecular cellulose and wood pulp, and as a result, they are being developed for applications that were once thought impossible for cellulosic materials. Momentum is growing in CN research and development, and commercialization in this field is happening because of the unique combination of characteristics (e.g., high mechanical properties, sustainability, and large-scale production potential) and utility across a broad spectrum of material applications (e.g. as an additive, self-sustaining structures, and template structures) that CNs offer. Despite the challenges typical for materials development, CN and near-CN production is ramping up with pilot scale to industry demonstration trials, and the first commercial products are starting to hit the marketplace. This review provides a broad overview of CNs and their capabilities that are enabling new application areas for cellulose-based materials. 419. Employing ionic liquids to deposit cellulose on PET fibers. Science.gov (United States) Textor, Torsten; Derksen, Leonie; Gutmann, Jochen S 2016-08-01 Several ionic liquids are excellent solvents for cellulose. Starting from that finishing of PET fabrics with cellulose dissolved in ionic liquids like 1-ethyl-3-methyl imidazolium acetate, diethylphosphate and chloride, or the chloride of butyl-methyl imidazolium has been investigated. Finishing has been carried out from solutions of different concentrations, using microcrystalline cellulose or cotton and by employing different cross-linkers. Viscosity of solutions has been investigated for different ionic liquids, concentrations, cellulose sources, linkers and temperatures. Since ionic liquids exhibit no vapor pressure, simple pad-dry-cure processes are excluded. Before drying the ionic liquid has to be removed by a rinsing step. Accordingly rinsing with fresh ionic liquid followed by water or the direct rinsing with water have been tested. The amount of cellulose deposited has been investigated by gravimetry, zinc chloride iodine test as well as reactive dyeing. Results concerning wettability, water up-take, surface resistance, wear-resistance or washing stability are presented. 420. Cellulose-reinforced composites: from micro-to nanoscale Directory of Open Access Journals (Sweden) Alain Dufresne 2013-01-01 Full Text Available This paper present the most relevant advances in the fields of: i cellulose fibres surface modification; ii cellulose fibres-based composite materials; and iii nanocomposites based on cellulose whiskers or starch platelet-like nanoparticles. The real breakthroughs achieved in the first topic concern the use of solvent-free grafting process (plasma and the grafting of the matrix at the surface of cellulose fibres through isocyanate-mediated grafting or thanks to "click chemistry". Concerning the second topic, it is worth to mention that for some cellulose/matrix combination and in the presence of adequate aids or specific surface treatment, high performance composite materials could be obtained. Finally, nanocomposites allow using the semi-crystalline nature and hierarchical structure of lignocellulosic fibres and starch granules to more deeply achieve this goal profitably exploited by Mother Nature « 19 20 21 22 23 » « 20 21 22 23 24 » 421. Una Aproximación al Estudio de la Actividad Distrital de los Diputados: los Casos de Chile y Bolivia Directory of Open Access Journals (Sweden) Mikel Barreda 2014-04-01 Full Text Available El paper se ocupa de la actividad de los diputados en sus distritos/circunscripciones en perÃodos no electorales. Se presta especial atención a la autonomÃa del diputado con respecto al partido en la definición de las actividades de representación en el distrito por el que fue electo. Dos son los objetivos principales del trabajo. En primer lugar, realizar una descripción de la actividad distrital, a partir de un análisis de la frecuencia, soportes y relación con el partido durante la actividad distrital. En segundo lugar, explorar algunos de los posibles determinantes del grado de autonomÃa de los diputados con respecto a sus partidos en su actividad distrital. Los casos elegidos son partidos de Bolivia y Chile. 422. Determinantes para la Práctica de Actividad FÃsica en Estudiantes Universitarios National Research Council Canada - National Science Library Ana Isabel Caro-Freile; Roberto Carlos Rebolledo-Cobos 2017-01-01 .... En Colombia la mayor parte de la población es inactiva, los niños son más activos, pero esta condición disminuye con la edad, el porcentaje de universitarios que realizan actividad fÃsica es bajo, está práctica está... 423. Actividad fÃsica y etapas de cambio comportamental en Bogotá. Directory of Open Access Journals (Sweden) Gustavo Cabrera Cabrera 2009-11-01 Full Text Available Objetivo: Determinar la distribución de etapas del cambio de comportamiento en la actividad fÃsica regular de residentes de Bogotá D.C., Colombia, en el año 2003. Métodos: Se estudió la prevalencia de intención o práctica regular de actividad fÃsica en residentes urbanos de los estratos I a IV en Bogotá, mayores de 18 y menores de 65 años, seleccionados probabilÃsticamente por conglomerados, estratos y tres etapas, encuestados domiciliarmente con consentimiento mediante formularios estructurados. Resultados: El porcentaje de respuesta fue 78% y se consideraron válidos 3,000 registros. Por no realizar actividad fÃsica regular ni contemplar hacerlo en los próximos seis meses 13% son precontempladores; 24% contempla hacerlo en el lapso de un semestre; 18% se preparaba para iniciarla en el próximo mes; 7% está en la etapa de acción por tener prácticas regulares en el último mes; 34% fueron clasificados como mantenedores y el restante 4% abandonó recientemente este tipo de actividad. Conclusiones: La distribución de etapas de cambio en la población adulta de los estratos I a IV de Bogotá son desfavorables tanto para riesgo cardiovascular como otros factores comportamentales negativos asociados con el estilo de vida urbano. 424. La actividad económica informal y el negocio de franquicia en Venezuela Directory of Open Access Journals (Sweden) Ana Prieto Sánchez 2008-01-01 Full Text Available En el presente artÃculo se plantea el negocio de franquicia como una alternativa viable para canalizar la problemática de la informalidad laboral en Venezuela. Con base a un análisis documental-bibliográfico, semuestra la aplicabilidad de dichomodelo en un proceso de reconversión de la actividad económica informal en el paÃs. Para lograrlo, se ha considerado la articulación entre diferentes conceptos económicos: el modelo de franquicia de conversión y la problemática de la economÃa informal en Venezuela, flagelo económico social presente en la realidad venezolana. Se concluye que un modelo de reconversión de la actividad económica informal representarÃa una alternativa para transformar esta actividad en el paÃs, planteándose la conformación de una PYME con fortalezas financiera y operacional, con altos niveles de racionalidad, cuya actividad principal es ejecutada por otros individuos de manera informal; de esta forma se estructura una estrategia de crecimiento en función de la absorción de los ejecutores informales quienes, a través del financiamiento público o privado, concretan la conformación de una microempresa y la firma de un contrato tipo franquicia con la PYME. 425. Actividad de glutatión peroxidasa y superóxido dismutasa OpenAIRE Granados Moreno, Jairo Enrique 2014-01-01 El artÃculo presenta los resultados de evaluar la actividad de las enzimas antioxidantes glutatión peroxidasa (GPx; EC 1.11.1.9), y superóxido dismutasa (SOD; EC 1.15.1.1) en sangre, plasma y plasma seminal y su relación con las caracterÃsticas seminales. 426. Actividad deportiva en pacientes con artroplastÃa total de rodilla Directory of Open Access Journals (Sweden) Dr. U. Jaime Duboy 2012-05-01 Por esto es importante conocer y difundir entre los pacientes y médicos qué restricciones y cuidados se debe tener en estos pacientes para las recomendaciones de actividad fÃsica y práctica deportiva que no comprometan la durabilidad del implante, siendo el objetivo de este artÃculo recalcar estos puntos. 427. Estrés laboral y actividad fÃsica en empleados Directory of Open Access Journals (Sweden) Gustavo Ramón Suárez 2014-01-01 Full Text Available La actividad fÃsica puede proteger del estrés laboral. El objetivo del presente trabajo fue correlacionar la actividad fÃsica y el estrés laboral en trabajadores universitarios de MedellÃn, a partir de un estudio correlacional en 120 empleados seleccionados aleatoriamente y tamizados con International Physical Activity Questionnaire y el Test de Maslach-Jackson para el estrés. Se calcularon proporciones, chi cuadrado, intervalos para diferencias de medias y correlación de Spearman. Se halló sedentarismo en el 71 %, alto agotamiento emocional del 29 %, despersonalización del 38 % y baja realización personal del 91 %. Se observó correlación inversa para la actividad fÃsica y el agotamiento emocional, y directa para despersonalización con agotamiento emocional y realización personal. Con esto resultados se concluyó que la inactividad fÃsica y el estrés laboral presentaron prevalencias elevadas; la actividad fÃsica presenta un efecto protector sobre el estrés. 428. Cepas nativas del bacterioneuston marino y su actividad inhibitoria de bacterias ictiopatógenas Directory of Open Access Journals (Sweden) Jorge León 2014-06-01 Full Text Available En la literatura cientÃfica, las bacterias marinas han sido consideradas con frecuencia como productores de sustancias antibacterianas. En este estudio, se investigó el potencial de actividad antibiótica in vitro de cepas nativas de bacterioneuston marino aisladas de las pozas intermareales de Montemar, BahÃa de Valparaiso, Chile. Se aislaron 71 cepas neustónicas antagonistas a Staphylococcus aureus ATCC 11632. Veinticinco de ellas, productoras de sustancias fuertemente inhibitorias, fueron evaluadas por su antagonismo frente a una colección de 15 bacterias ictiopatógenas. Aplicando métodos clásicos para bacterias marinas, se caracterizaron fenotÃpicamente orientados a la identificación. Los resultados de antibiosis indican que la totalidad cle las ictiopatógenas en prueba son susceptibles a la actividad inhibitoria de las cepas neustónicas, siendo V anguillarum NCMB 2133, V ordalii 84/2559 y V tubiashii EX1 las más sensibles. Entre las cepas aisladas del neuston se identificaron miembros de los géneros Vibrio spp. (28%, Flavobacterium spp. (12%, Alteromonas-Marinomonas (12%, Pseudomonas spp (8% y Micrococcus spp, (4%. Nueve cepas (36% no fueron identificadas. Los resultados de actividades inhibitorias frente a ictiopatógenos sugieren que dichas cepas o sus productos pudieran ser útiles en actividades de cultivos intensivos de maricultura de peces, moluscos y crustáceos. 429. Arte africano como punto de partida para una actividad de arte terapia OpenAIRE Vassiliadou Yiannaka, MarÃa 2001-01-01 La visita a una exposición de arte africano realizada con un grupo de pacientes de un Hospital Psiquiátrico sirve en este artÃculo para reflexionar sobre los aspectos implicados en la organización de actividades de arte terapia y sobre el problema de la accesibilidad de todos los ciudadanos a la vida cultural 430. Autoestima como variable psicosocial predictora de la actividad fÃsica en personas mayores Directory of Open Access Journals (Sweden) Alfonso J. Garc\\u00EDa 2012-01-01 Full Text Available El propósito del presente estudio es investigar acerca de la relación existente entre la Autoestima manifestada por personas mayores de 65 años y la realización de actividad fÃsica. El autoconcepto y la Autoestima aparecen como componentes psicológicos fundamentales de la calidad de vida durante la adultez mayor y del bienestar personal. La Autoestima ha sido propuesta como un área de intervención para mejorar la calidad de vida en la población mayor. La muestra la componen 184 personas mayores, de las que 92 realizan actividad fÃsica frecuentemente y otras 92 desarrollan un estilo de vida sedentario. Se aplicó el cuestionario de Autoestima personal de Rosenberg. Los resultados muestran diferentes niveles de Autoestima entre los mayores que realizan actividad fÃsica y los que no, siendo significativamente más alta en los primeros. Estudios con objetivos similares demuestran y apoyan la comprobación de la hipótesis de partida que establece la relación positiva entre la Autoestima y la realización de actividad fÃsica. 431. Lightweight, highly compressible, noncrystalline cellulose capsules. Science.gov (United States) Carrick, Christopher; Lindström, Stefan B; Larsson, Per Tomas; WÃ¥gberg, Lars 2014-07-08 We demonstrate how to prepare extraordinarily deformable, gas-filled, spherical capsules from nonmodified cellulose. These capsules have a low nominal density, ranging from 7.6 to 14.2 kg/m(3), and can be deformed elastically to 70% deformation at 50% relative humidity. No compressive strain-at-break could be detected for these dry cellulose capsules, since they did not rupture even when compressed into a disk with pockets of highly compressed air. A quantitative constitutive model for the large deformation compression of these capsules is derived, including their high-frequency mechanical response and their low-frequency force relaxation, where the latter is governed by the gas barrier properties of the dry capsule. Mechanical testing corroborated these models with good accuracy. Force relaxation measurements at a constant compression rendered an estimate for the gas permeability of air through the capsule wall, calculated to 0.4 mL μm/m(2) days kPa at 50% relative humidity. These properties taken together open up a large application area for the capsules, and they could most likely be used for applications in compressible, lightweight materials and also constitute excellent model materials for adsorption and adhesion studies. 432. Starch composites reinforced by bamboo cellulosic crystals. Science.gov (United States) Liu, Dagang; Zhong, Tuhua; Chang, Peter R; Li, Kaifu; Wu, Qinglin 2010-04-01 Using a method of combined HNO(3)-KClO(3) treatment and sulfuric acid hydrolysis, bamboo cellulose crystals (BCCs) were prepared and used to reinforce glycerol plasticized starch. The structure and morphology of BCCs were investigated using X-ray diffraction, electron microscopy, and solid-state (13)C NMR. Results showed that BCCs were of typical cellulose I structure, and the morphology was dependent on its concentration in the suspension. BCC of 50-100 nm were assembled into leaf nervations at low concentration (i.e. 0.1 wt.% of solids), but congregated into a micro-sized "flower" geometry at high concentration (i.e. 10.0 wt.% of solids). Tensile strength and Young's modulus of the starch/BCC composite films (SBC) were enhanced by the incorporation of the crystals due to reinforcement of BCCs and reduction of water uptake. BCCs at the optimal 8% loading level exhibited a higher reinforcing efficiency for plasticized starch plastic than any other loading level. 433. Modification of cellulose for high glucose generation. Science.gov (United States) Jiang, Xue; Gu, Jian; Tian, Xiuzhi; Li, Yali; Huang, Dan 2012-01-01 The influence of introduction of cyanuric chloride on glucose's yield (Y) in acid-catalyzed hydrolysis of microcrystalline cellulose (MCC) has been studied. The content of cyanuric chloride (C) in modified MCCs was determined by X-ray photoelectric spectroscopy. The chemical structures of modified MCCs were analyzed by Fourier transformation-infrared spectroscopy and cross polarization/magic angle spinning (13)C nuclear magnetic resonance. Crystal index (CI) and the ratio (R) representing the sum of content of (1 Ì…10) and (110) to that of (200) were calculated based on diffraction intensity in wide angle X-ray diffraction (WAXD). Hydrolysis experiment and WAXD show that Y, CI and R vary with C. The modified MCC containing 3.9 mol% of cyanuric chloride has the highest Y, the highest R and the lowest CI. Variations of CI and R show that the chemical modification changed the proportion of crystal/amorphous and crystal planes, both of which influence glucose's generation in hydrolysis of cellulose. 434. Communication and Sensing Circuits on Cellulose Directory of Open Access Journals (Sweden) Federico Alimenti 2015-06-01 Full Text Available This paper proposes a review of several circuits for communication and wireless sensing applications implemented on cellulose-based materials. These circuits have been developed during the last years exploiting the adhesive copper laminate method. Such a technique relies on a copper adhesive tape that is shaped by a photo-lithographic process and then transferred to the hosting substrate (i.e., paper by means of a sacrificial layer. The presented circuits span from UHF oscillators to a mixer working at 24 GHz and constitute an almost complete set of building blocks that can be applied to a huge variety communication apparatuses. Each circuit is validated experimentally showing performance comparable with the state-of-the-art. This paper demonstrates that circuits on cellulose are capable of operating at record frequencies and that ultra- low cost, green i.e., recyclable and biodegradable materials can be a viable solution to realize high frequency hardware for the upcoming Internet of Things (IoT era. 435. CELLULOSE DECOMPOSTION IN TROPICAL PEAT SWAMPS Institute of Scientific and Technical Information of China (English) Hjh Dulima Jali 2003-01-01 Given that organic soil is a complex substrate and there are many environmental factors which directly or indirectly control its decomposition processes, the use of standard substrate simplify the system in that the effect of substrate quality could be eliminated and influence of certain environmental conditions such as edaphic factors, acidity and moisture could be focused on. In addition to the forest floor, decomposition potential down the peat profile can also be examined. Cotton strip assay was used to estimate decomposition potentials in tropical peat swamp occupied by different Shorea Albida peat swamp forest communities, The' Alan Batu' , the ' Alan Bunga' ,

the' Alan Padang' and the 'mixed Alan'forest communities. Greatest decay rates on the peat surface took place during the wet period. The moist condition of the wet months appeared to favour the growth and stimulate activities of decomposer population and soil invertebrates.Generally, 50% of cotton tensile loss is achieved after four weeks of exposure. The results suggest that cellulose decomposition is influenced by the environmental variables of hydrological regime, water-table fluctuation, aeration, moisture availability,waterlogging and the resultant anaerobiosis, peat depths, and micro-sites characteristics. Decomposition of cellulose is inhibited by waterlogging and the resultant anaerobiosis in thelower segment of the cotton strip during wet periods and under dry conditions in the surface segment of the cotton strip during periods of less rain. 436. Graphene-cellulose paper flexible supercapacitors Energy Technology Data Exchange (ETDEWEB) Weng, Zhe; Su, Yang; Li, Feng; Du, Jinhong; Cheng, Hui-Ming [Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, 72 Wenhua Road, Shenyang 110016 (China); Wang, Da-Wei [ARC Centre of Excellence for Functional Nanomaterials, Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, St Lucia, Brisbane, Qld 4072 (Australia) 2011-10-15 A simple and scalable method to fabricate graphene-cellulose paper (GCP) membranes is reported; these membranes exhibit great advantages as freestanding and binder-free electrodes for flexible supercapacitors. The GCP electrode consists of a unique three-dimensional interwoven structure of graphene nanosheets and cellulose fibers and has excellent mechanical flexibility, good specific capacitance and power performance, and excellent cyclic stability. The electrical conductivity of the GCP membrane shows high stability with a decrease of only 6% after being bent 1000 times. This flexible GCP electrode has a high capacitance per geometric area of 81 mF cm{sup -2}, which is equivalent to a gravimetric capacitance of 120 F g{sup -1} of graphene, and retains >99% capacitance over 5000 cycles. Several types of flexible GCP-based polymer supercapacitors with various architectures are assembled to meet the power-energy requirements of typical flexible or printable electronics. Under highly flexible conditions, the supercapacitors show a high capacitance per geometric area of 46 mF cm{sup -2} for the complete devices. All the results demonstrate that polymer supercapacitors made using GCP membranes are versatile and may be used for flexible and portable micropower devices. (Copyright copyright 2011 WILEYVCH Verlag GmbH and Co. KGaA, Weinheim) 437. Net energy of cellulosic ethanol from switchgrass. Science.gov (United States) Schmer, M R; Vogel, K P; Mitchell, R B; Perrin, R K 2008-01-15 Perennial herbaceous plants such as switchgrass (Panicum virgatum L.) are being evaluated as cellulosic bioenergy crops. Two major concerns have been the net energy efficiency and economic feasibility of switchgrass and similar crops. All previous energy analyses have been based on data from research plots (biomass energy crop in field trials of 3-9 ha (1 ha = 10,000 m2) on marginal cropland on 10 farms across a wide precipitation and temperature gradient in the midcontinental U.S. to determine net energy and economic costs based on known farm inputs and harvested yields. In this report, we summarize the agricultural energy input costs, biomass yield, estimated ethanol output, greenhouse gas emissions, and net energy results. Annual biomass yields of established fields averaged 5.2-11.1 Mg x ha(-1) with a resulting average estimated net energy yield (NEY) of 60 GJ x ha(-1) x y(-1). Switchgrass produced 540% more renewable than nonrenewable energy consumed. Switchgrass monocultures managed for high yield produced 93% more biomass yield and an equivalent estimated NEY than previous estimates from human-made prairies that received low agricultural inputs. Estimated average greenhouse gas (GHG) emissions from cellulosic ethanol derived from switchgrass were 94% lower than estimated GHG from gasoline. This is a baseline study that represents the genetic material and agronomic technology available for switchgrass production in 2000 and 2001, when the fields were planted. Improved genetics and agronomics may further enhance energy sustainability and biofuel yield of switchgrass. 438. Cellulose-hemicellulose interaction in wood secondary cell-wall Science.gov (United States) Zhang, Ning; Li, Shi; Xiong, Liming; Hong, Yu; Chen, Youping 2015-12-01 The wood cell wall features a tough and relatively rigid fiber reinforced composite structure. It acts as a pressure vessel, offering protection against mechanical stress. Cellulose microfibrils, hemicellulose and amorphous lignin are the three major components of wood. The structure of secondary cell wall could be imagined as the same as reinforced concrete, in which cellulose microfibrils acts as reinforcing steel bar and hemicellulose-lignin matrices act as the concrete. Therefore, the interface between cellulose and hemicellulose/lignin plays a significant role in determine the mechanical behavior of wood secondary cell wall. To this end, we present a molecular dynamics (MD) simulation study attempting to quantify the strength of the interface between cellulose microfibrils and hemicellulose. Since hemicellulose binds with adjacent cellulose microfibrils in various patterns, the atomistic models of hemicellulose-cellulose composites with three typical binding modes, i.e. bridge, loop and random binding modes are constructed. The effect of the shape of hemicellulose chain on the strength of hemicellulose-cellulose composites under shear loadings is investigated. The contact area as well as hydrogen bonds between cellulose and hemicellulose, together with the covalent bonds in backbone of hemicellulose chain are found to be the controlling parameters which determine the strength of the interfaces in the composite system. For the bridge binding model, the effect of shear loading direction on the strength of the cellulose material is also studied. The obtained results suggest that the shear strength of wood-inspired engineering composites can be optimized through maximizing the formations of the contributing hydrogen bonds between cellulose and hemicellulose. 439. Enzymic modification of cellulose - xyloglucan networks : implications for fruit juice processing = Enzymatische modificatie van cellulose - xyloglucaan netwerken NARCIS (Netherlands) Vincken, J.P. 1996-01-01 Xyloglucans play an important role in connecting cellulose microfibrils in the primary coli wall of plants, and the resulting cellulose-xyloglucan network is thought to determine the strength of these walls. Xyloglucans were isolated from apple fruit and potato tuber cell wall material by 440. Use of recombinant cellulose-binding domains of Trichoderma reesei cellulase as a selective immunocytochemical marker for cellulose in protozoa. Science.gov (United States) Linder, Markus; Winiecka-Krusnell, Jadwiga; Linder, Ewert 2002-05-01 Some unicellular organisms are able to encyst as a protective response to a harmful environment. The cyst wall usually contains chitin as its main structural constituent, but in some cases, as in Acanthamoeba, it consists of cellulose instead. Specific cytochemical differentiation between cellulose and chitin by microscopy has not been possible, due to the similarity of their constituent beta-1,4-linked hexose backbones. Thus, various fluorescent brightening agents and lectins bind to both cellulose and chitin. We have used a recombinant cellulose-binding protein consisting of two cellulose-binding domains (CBDs) from Trichoderma reesei cellulases linked together in combination with monoclonal anticellulase antibodies and anti-mouse immunoglobulin fluorescein conjugate to specifically stain cellulose in the cysts of Acanthamoeba strains for fluorescence microscopy imaging. Staining was observed in ruptured cysts and frozen sections of cysts but not in intact mature cysts. No staining reaction was observed with the chitin-containing cyst walls of Giardia intestinalis, Entamoeba dispar, or Pneumocystis carinii. Thus, the recombinant CBD can be used as a marker to distinguish between cellulose and chitin. Thirteen of 25 environmental or clinical isolates of amoebae reacted in the CBD binding assay. All 13 isolates were identified as Acanthamoeba spp. Five isolates of Hartmannella and seven isolates of Naegleria tested negative in the CBD binding assay. Whether cyst wall cellulose really is a unique property of Acanthamoeba spp. among free-living amoebae, as suggested by our findings, remains to be shown in more extensive studies. « 20 21 22 23 24 » « 21 22 23 24 25 » 441. Tunable Semicrystalline Thin Film Cellulose Substrate for High-Resolution, In-Situ AFM Characterization of Enzymatic Cellulose Degradation. Science.gov (United States) Ganner, Thomas; RoÅker, Stephanie; Eibinger, Manuel; Kraxner, Johanna; Sattelkow, Jürgen; Rattenberger, Johannes; Fitzek, Harald; Chernev, Boril; Grogger, Werner; Nidetzky, Bernd; Plank, Harald 2015-12-23 In the field of enzymatic cellulose degradation, fundamental interactions between different enzymes and polymorphic cellulose materials are of essential importance but still not understood in full detail. One technology with the potential of direct visualization of such bioprocesses is atomic force microscopy (AFM) due to its capability of real-time in situ investigations with spatial resolutions down to the molecular scale. To exploit the full capabilities of this technology and unravel fundamental enzymecellulose bioprocesses, appropriate cellulose substrates are decisive. In this study, we introduce a semicrystalline-thin-film-cellulose (SCFTC) substrate which fulfills the strong demands on such ideal cellulose substrates by means of (1) tunable polymorphism via variable contents of homogeneously sized cellulose nanocrystals embedded in an amorphous cellulose matrix; (2) nanoflat surface topology for high-resolution and high-speed AFM; and (3) fast, simple, and reproducible fabrication. The study starts with a detailed description of SCTFC preparation protocols including an in-depth material characterization. In the second part, we demonstrate the suitability of SCTFC substrates for enzymatic degradation studies by combined, individual, and sequential exposure to TrCel6A/TrCel7A cellulases (Trichoderma reesei) to visualize synergistic effects down to the nanoscale. 442. Characterization of blend hydrogels based on plasticized starch/cellulose acetate/carboxymethyl cellulose synthesized by electron beam irradiation Science.gov (United States) Senna, Magdy M.; Mostafa, Abo El-Khair B.; Mahdy, Sanna R.; El-Naggar, Abdel Wahab M. 2016-11-01 Blend hydrogels based on aqueous solutions of plasticized starch and different ratios of cellulose acetate (CA) and carboxymethyl cellulose (CMC) were prepared by electron beam irradiation (EB). The blends before and after EB irradiation were characterized by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The physico-chemical properties of blend hydrogels prepared by electron beam irradiation were improved compared to unirradiated blends. 443. Properties of films composed of cellulose nanowhiskers and a cellulose matrix regenerated from alkali/urea solution. Science.gov (United States) Qi, Haisong; Cai, Jie; Zhang, Lina; Kuga, Shigenori 2009-06-01 All-cellulose composite films were prepared, for the first time, from native cellulose nanowhiskers and cellulose matrix regenerated from aqueous NaOH-urea solvent system on the basis of their temperature-dependent solubility. The cellulose whiskers retained their needlelike morphology with mean length and diameter of 300 and 21 nm as well as native crystallinity when added to the latter solution at ambient temperature. The structure and physical properties of the nanocomposite films were characterized by scanning electron microscope, X-ray diffraction, and tensile tests. The composite films were isotropic and transparent to visible light and showed good mechanical properties as a result of the reinforcement by the whiskers. By varying the ratio of the cellulose whiskers to regenerated cellulose matrix (cellulose II), the tensile strength and elastic modulus of the nanocomposite films could be tuned to reach 124 MPa and 5 GPa, respectively. The tensile strength of the nanocomposite films could reach 157 MPa through a simple drawing process, with the calculated Hermans' orientation parameter of 0.30. This work provided a novel pathway for the preparation of biodegradable all-cellulose nanocomposites, which are expected to be useful as biomaterials and food ingredients. 444. Preparation of cellulose II and III{sub I} films by allomorphic conversion of bacterial cellulose I pellicles Energy Technology Data Exchange (ETDEWEB) Faria-Tischer, Paula C.S., E-mail: [email protected] [BioPol, Departamento de QuÃmica, UFPR, Cx. Postal 19081, 81531-980 Curitiba, PR (Brazil); Université Grenoble Alpes, Centre de Recherches sur les Macromolécules Végétales (CERMAV), F-38000 Grenoble (France); CNRS, CERMAV, F-38000 Grenoble (France); UMR 5628 (LMGP), CNRS and Grenoble Institute of Technology, 3 Parvis Louis Néel, F-38016 Grenoble Cedex 1 (France); Tischer, Cesar A. [BioPol, Departamento de QuÃmica, UFPR, Cx. Postal 19081, 81531-980 Curitiba, PR (Brazil); Université Grenoble Alpes, Centre de Recherches sur les Macromolécules Végétales (CERMAV), F-38000 Grenoble (France); CNRS, CERMAV, F-38000 Grenoble (France); CIME Nanotech, 3 Parvis Louis Néel, F38016 Grenoble Cedex 1 (France); Heux, Laurent [Université Grenoble Alpes, Centre de Recherches sur les Macromolécules Végétales (CERMAV), F-38000 Grenoble (France); CNRS, CERMAV, F-38000 Grenoble (France); Le Denmat, Simon; Picart, Catherine [UMR 5628 (LMGP), CNRS and Grenoble Institute of Technology, 3 Parvis Louis Néel, F-38016 Grenoble Cedex 1 (France); Sierakowski, Maria-R. [BioPol, Departamento de QuÃmica, UFPR, Cx. Postal 19081, 81531980 Curitiba, PR (Brazil); and others 2015-06-01 The structural changes resulting from the conversion of native cellulose I (Cel I) into allomorphs II (Cel II) and III{sub I} (Cel III{sub I}) have usually been studied using powder samples from plant or algal cellulose. In this work, the conversion of Cel I into Cel II and Cel III{sub I} was performed on bacterial cellulose films without any mechanical disruption. The surface texture of the films was observed by atomic force microscopy (AFM) and the morphology of the constituting cellulose ribbons, by transmission electron microscopy (TEM). The structural changes were characterized using solid-state NMR spectroscopy as well as X-ray and electron diffraction. The allomorphic change into Cel II and Cel III{sub I} resulted in films with different crystallinity, roughness and hydrophobic/hydrophilicity surface and the films remained intact during all process of allomorphic conversion. - Highlights: • Description of a method to modify the allomorphic structure of bacterial cellulose films • Preparation of films with specific morphologies and hydrophobic/hydrophilic surface characters • First report on cellulose III films from bacterial cellulose under swelling conditions • Detailed characterization of cellulose II and III films with complementary techniques • Development of films with specific properties as potential support for cells, enzymes, and drugs. 445. Immobilization of Glucose Oxidase on Cellulose/Cellulose Acetate Membrane and its Detection by Scanning Electrochemical Microscope (SECM) Institute of Scientific and Technical Information of China (English) Jin Sheng ZHAO; Zhen Yu YANG; Yi He ZHANG; Zheng Yu YANG 2004-01-01 Cellulose/cellulose acetate membranes were prepared and functionalized by introducing amino group on it, and then immobilized the glucose oxidase (Gox) on the functionalizd membrane. SECM was applied for the detection of enzyme activity immobilized on the membrane. Immobilized biomolecules on such membranes was combined with analysis apparatus and can be used in bioassays. 446. Cellulosic ethanol. Potential, technology and development status Energy Technology Data Exchange (ETDEWEB) Rarbach, M. [Sued-Chemie AG, Muenchen (Germany) 2012-07-01 In times of rising oil prices and a growing energy demand, sustainable alternative energy sources are needed. Cellulosic ethanol is a sustainable biofuel, made from lignocellulosic feedstock such as agricultural residues (corn stover, cereal straw, bagasse) or dedicated energy crops. Its production is almost carbon neutral, doesn't compete with food or feed production and induces no land use changes. It constitutes a new energy source using an already existing renewable feedstock without needing any further production capacity and can thus play a major role on the way to more sustainability in transport and the chemical industry and reducing the dependence on the import of fossil resources. The potential for cellulosic ethanol is huge: In the US, the annual production of agricultural residues (cereal straw and corn stover) reached almost 384 million tons in 2009 and Brazil alone produced more than 670 million tons of sugar cane in 2009 yielding more than 100 million tons of bagasse (dry basis). And alone in the European Union, almost 300 million tons of crop straw are produced annually. The last years have seen success in the development and deployment in the field of cellulosic ethanol production. The main challenge thereby remains to demonstrate that the technology is economically feasible for the up-scaling to industrial scale. Clariant has developed the sunliquid {sup registered} process, a proprietary cellulosic ethanol technology that reaches highest greenhouse gas (GHG) emission savings while cutting production costs to a minimum. The sunliquid {sup registered} process for cellulosic ethanol matches the ambitious targets for economically and ecologically sustainable production and greenhouse gas reduction. It was developed using an integrated design concept. Highly optimized, feedstock and process specific biocatalysts and microorganisms ensure a highly efficient process with improved yields and feedstock-driven production costs. Integrated, on 447. Optimization of cellulose acrylate and grafted 4-vinylpyridine and 1-vinylimidazole synthesis Directory of Open Access Journals (Sweden) Bojanić Vaso 2010-01-01 Full Text Available Optimization of cellulose acrylate synthesis by reaction with sodium cellulosate and acryloyl chloride was carried out. Optimal conditions for conducting the synthesis reaction of cellulose acrylate were as follows: the molar ratio of cellulose/potassium-t-butoxide/acryloyl chloride was 1:3:10 and the optimal reaction time was 10 h. On the basis of elemental analysis with optimal conditions for conducting the reaction of cellulose acrylate, the percentage of substitution of glucose units in cellulose Y = 80.7%, and the degree of substitution of cellulose acrylate DS = 2.4 was determined. The grafting reaction of acrylate vinyl monomers onto cellulose in acetonitrile with initiator azoisobutyronitrile (AIBN in a nitrogen atmosphere was performed, by mixing for 5 h at acetonitrile boiling temperature. Radical copolymerization of synthesized cellulose acrylate and 4-vinylpyridine, 1-vinylimidazole, 1-vinyl-2-pyrrolidinone and 9-vinylcarbazole, cellulose-poly-4-vinylpyridine (CellPVP, cellulose-poly-1- vinylimidazole (Cell-PVIm and cellulose-poly-1-vinyl-2-pyrrolidinone (Cell-P1V2P and cellulose-poly-9-vinylcarbazole (Cell-P9VK were synthesized. Acrylate cellulose and cellulose grafted copolymers were confirmed by IR spectroscopy, based on elementary analysis and the characteristics of grafted copolymers of cellulose were determined. The mass share of grafted copolymers, X, the relationship of derivative parts/cellulose vinyl group, Z, and the degree of grafting copolymers of cellulose (mass% were determined. In reaction of methyl iodide and cellulose-poly-4-vinylpyridine (Cell-PVP the cellulose-1-methyl-poly-4-vinylpyridine iodide (Cell-1-Me-PVPJ was synthesized. Cellulose acrylate and grafted copolymers were obtained with better thermal, electrochemical and ion-emulation properties for bonding of noble metals Au, Pt, Pd from water solutions. The synthesis optimization of cellulose acrylate was applied as a model for the synthesis of grafted 448. Actividades intersectoriales en la prevención de accidentes de tráfico Directory of Open Access Journals (Sweden) Peiró R. 2003-01-01 Full Text Available Se describen las lÃneas de trabajo priorizadas y algunos resultados obtenidos en la implantación del programa de prevención y reducción de lesiones por accidentes de tráfico en un área de salud. A partir de 1999 el Centro de Salud Pública priorizó la identificación y búsqueda de aliados en otros sectores (Asociación de policÃas locales y educación, la construcción de la capacidad de trabajo conjunta y la formación de un grupo intersectorial. Se llevaron a cabo actividades docentes y jornadas. Se formó una red de personas en 17 de un total de 39 ayuntamientos que participan con actividades en el grupo intersectorial. Un total de 10 de estos ayuntamientos participaron con actividades educativas y siete, además, exigieron al cumplimiento de la legislación. El grupo intersectorial potenció la visibilidad de sus actividades a través de los medios de comunicación local. Estas actividades no están dirigidas a reducir las lesiones por tráfico, sino a crear un marco de trabajo para la movilización de los sectores implicados. Se pretende potenciar más el compromiso entre los niveles polÃticos, técnicos y civiles incidiendo en valores sociales de respeto para una vida más saludable. 449. Método para el Modelado y Prueba de Diagramas de Actividades Mediante Redes de Petri Directory of Open Access Journals (Sweden) Lionel Baquero Hernández 2015-11-01 Full Text Available Las redes de Petri son ideales para describir y estudiar sistemas que procesan información y con caracterÃsticas concurrentes, asÃncronas, distribuidas, paralelas, no determinÃsticas y/o estocásticas. . Sin embargo, la teorÃa clásica de estas redes se enfrenta al desafÃo de adecuarse a las nuevas necesidades de los sistemas informáticos que los ingenieros diseñan en la actualidad. Un diagrama de actividades representa una secuencia de actividades. PodrÃa aplicarse a cualquier propósito, pero se considera especialmente útil para visualizar los flujos de trabajo y los procesos del negocio, o casos de uso. El presente trabajo se ha

desarrollado con el objetivo de diseñar un método para el modelado y prueba de diagramas de actividades mediante redes de Petri. El método propuesto brinda una serie de pasos necesarios para modelar un diagrama de actividades con redes de Petri y a partir de dicha red obtener una representación matemática de la misma. Esta representación matemática se utiliza para con ella realizar una serie de operaciones basadas en el marcaje de la red que permiten realizar pruebas al diagrama. Este método es capaz de identificar errores comunes que se cometen en el modelado de los diagramas de actividades, lo cual se demostró a través del método de experimentación. 450. Actividad antioxidante de esteroles y ácidos orgánicos naturales Directory of Open Access Journals (Sweden) Mastro-Durán, R. 1993-06-01 Full Text Available This paper deals with antioxidant activity of sterols and natural organic acids not covered on previous papers. The paper «Antioxidant activity of phenolic compounds» covered phenolic acids; the second one «Antioxidant activity of vitamin C, D and provitamin A», ascorbic acid, and the third «Antioxidant activity of natural nitrogenous compounds», aminoacids. The acids studied here included citric, malic, lactic, fumarle, tartaric, kojic (5-hydroxy-2-[hydroxymethyl-γpyrone], phytic (inositol-hexaphosphoric acid and furoic acids. The reaction mechanisms, either as inhibitors of the chain reaction of prooxidant radicals or by sequestration of free radicals was discussed. Finally, a list of recent patents of these compounds and their derivatives as antioxidants or synergists was included. Actividad antioxidante de esteroles y ácidos orgánicos naturales. Continuando el estudio de los antioxidantes naturales, se incluyen en este trabajo los esteroles y los ácidos orgánicos no estudiados en los trabajos anteriores (ácidos fenólicos, en «Actividad antioxidante de los compuestos fenólicos»: ácido ascórbico, en «Actividad antioxidante de las vitaminas C y D y de la provitamina A», aminoácidos, en «Actividad antioxidante de compuestos naturales nitrogenados». Los ácidos orgánicos cuya actividad como antioxidantes se estudia en este trabajo son: cÃtrico, málico, láctico, fumárico, sórbico, tartárico, kójico, fÃtico y furoicos. Se discuten sus mecanismos de reacción en cadena de los radicales prooxidantes, bien por secuestro de estos radicales. Finalmente, se citan las patentes registradas en los últimos años por estos compuestos o sus derivados como antioxidantes o como sinergistas con otros productos. 451. Discrimination between naphthacene and triphenylene using cellulose tris(4-methylbenzoate) and cellulose tribenzoate: A computational study. Science.gov (United States) Murakami, Yusuke; Shibata, Tohru; Ueda, Kazuyoshi 2017-02-01 The mechanisms of naphthacene and triphenylene discrimination using commercially available cellulose tris(4-methylbenzoate) (CMB) and cellulose tribenzoate (CB) chiral stationary phases were investigated using molecular mechanics calculations. Naphthacene and triphenylene could be separated by liquid chromatography on CMB and CB, with triphenylene being eluted earlier than naphthacene on both phases. However, the corresponding separation factor is much larger for CMB than for CB. The docking of these polycyclic aromatic hydrocarbons to the above polymers suggested that the most important sites of CMB and CB for interacting with these hydrocarbons are located at equivalent positions, featuring a space surrounded by main chain glucose units and benzoyl side chains. The difference of hydrocarbon stabilization energies with CMB and CB agreed well with the observed chromatographic separation factors. 452. Biochemical Disincentives to Fertilizing Cellulosic Ethanol Crops Science.gov (United States) Gallagher, M. E.; Hockaday, W. C.; Snapp, S.; McSwiney, C.; Baldock, J. 2010-12-01 Corn grain biofuel crops produce the highest yields when the cropping ecosystem is not nitrogen (N)-limited, achieved by application of fertilizer. There are environmental consequences for excessive fertilizer application to crops, including greenhouse gas emissions, hypoxic “dead zones,†and health problems from N runoff into groundwater. The increase in corn acreage in response to demand for alternative fuels (i.e. ethanol) could exacerbate these problems, and divert food supplies to fuel production. A potential substitute for grain ethanol that could reduce some of these impacts is cellulosic ethanol. Cellulosic ethanol feedstocks include grasses (switchgrass), hardwoods, and crop residues (e.g. corn stover, wheat straw). It has been assumed that these feedstocks will require similar N fertilization rates to grain biofuel crops to maximize yields, but carbohydrate yield versus N application has not previously been monitored. We report the biochemical stocks (carbohydrate, protein, and lignin in Mg ha-1) of a corn ecosystem grown under varying N levels. We measured biochemical yield in Mg ha-1 within the grain, leaf and stem, and reproductive parts of corn plants grown at seven N fertilization rates (0-202 kg N ha-1), to evaluate the quantity and quality of these feedstocks across a N fertilization gradient. The N fertilization rate study was performed at the Kellogg Biological Station-Long Term Ecological Research Site (KBS-LTER) in Michigan. Biochemical stocks were measured using 13C nuclear magnetic resonance spectroscopy (NMR), combined with a molecular mixing model (Baldock et al. 2004). Carbohydrate and lignin are the main biochemicals of interest in ethanol production since carbohydrate is the ethanol feedstock, and lignin hinders the carbohydrate to ethanol conversion process. We show that corn residue carbohydrate yields respond only weakly to N fertilization compared to grain. Grain carbohydrate yields plateau in response to fertilization at 453. Cellulose based hybrid hydroxylated adducts for polyurethane foams Science.gov (United States) De Pisapia, Laura; Verdolotti, Letizia; Di Mauro, Eduardo; Di Maio, Ernesto; Lavorgna, Marino; Iannace, Salvatore 2012-07-01 Hybrid flexible polyurethane foams (HPU) were synthesized by using a hybrid hydroxilated adduct (HHA) based on renewable resources. In particular the HHA was obtained by dispersing cellulose wastes in colloidal silica at room temperature, pressure and humidity. The colloidal silica was selected for its ability of modifying the cellulose structure, by inducing a certain "destructurization" of the crystalline phase, in order to allow cellulose to react with di-isocyanate for the final synthesis of the polyurethane foam. In fact, cellulose-polysilicate complexes are engaged in the reaction with the isocyanate groups. This study provides evidence of the effects of the colloidal silica on the cellulose structure, namely, a reduction of the microfiber cellulose diameter and the formation of hydrogen bonds between the polysilicate functional groups and the hydroxyl groups of the cellulose, as assessed by IR spectroscopy and solid state NMR. The HHA was added to a conventional polyol in different percentages (between 5 and 20%) to synthesize HPU in presence of catalysts, silicone surfactant and diphenylmethane diisocyanate (MDI). The mixture was expanded in a mold and cured for two hours at room temperature. Thermal analysis, optical microscopy and mechanical tests were performed on the foams. The results highlighted an improvement of thermal stability and a decrease of the cell size with respect neat polyurethane foam. Mechanical tests showed an improvement of the elastic modulus and of the damping properties with increasing HHA amount. 454. Smart Cellulose Fibers Coated with Carbon Nanotube Networks Directory of Open Access Journals (Sweden) Haisong Qi 2014-11-01 Full Text Available Smart multi-walled carbon nanotube (MWCNT-coated cellulose fibers with a unique sensing ability were manufactured by a simple dip coating process. The formation of electrically-conducting MWCNT networks on cellulose mono- and multi-filament fiber surfaces was confirmed by electrical resistance measurements and visualized by scanning electron microscopy. The interaction between MWCNT networks and cellulose fiber was investigated by Raman spectroscopy. The piezoresistivity of these fibers for strain sensing was investigated. The MWCNT-coated cellulose fibers exhibited a unique linear strain-dependent electrical resistance change up to 18% strain, with good reversibility and repeatability. In addition, the sensing behavior of these fibers to volatile molecules (including vapors of methanol, ethanol, acetone, chloroform and tetrahydrofuran was investigated. The results revealed a rapid response, high sensitivity and good reproducibility for these chemical vapors. Besides, they showed good selectivity to different vapors. It is suggested that the intrinsic physical and chemical features of cellulose fiber, well-formed MWCNT networks and favorable MWCNT-cellulose interaction caused the unique and excellent sensing ability of the MWCNT-coated cellulose fibers, which have the potential to be used as smart materials. 455. Nanocrystalline cellulose extracted from pine wood and corncob. Science.gov (United States) Ditzel, Fernanda I; Prestes, Eduardo; Carvalho, Benjamim M; Demiate, Ivo M; Pinheiro, LuÃs A 2017-02-10 The extraction of nanocrystalline cellulose from agro-residues is an interesting alternative to recover these materials. In the present study, nanocrystalline cellulose was extracted from pine wood and corncob. In addition, microcrystalline cellulose was used as a reference to compare results. Initially, the lignocellulosic residues were submitted to delignification pre-treatments. At the end of the process, the bleached fibre was submitted to acid hydrolysis. Additionally, microparticles were obtained from the spray-drying of the nanocrystalline cellulose suspensions. The nanocrystalline cellulose yield for the pine wood was 9.0-% of the value attained for the microcrystalline cellulose. For the corncob, the value was 23.5-%. Therefore, complementary studies are necessary to improve the yield. The spray-dried microparticles showed a crystallinity index of 67.8-% for the pine wood, 70.9-% for the corncob and 79.3-% for the microcrystalline cellulose. These microparticles have great potential for use in the production of polymer composites processed by extrusion. 456. Biological evaluation of nanosilver incorporated cellulose pulp for hygiene products. Science.gov (United States) Kavitha Sankar, P C; Ramakrishnan, Reshmi; Rosemary, M J 2016-04-01 Cellulose pulp has a visible market share in personal hygiene products such as sanitary napkins and baby diapers. However it offers good surface for growth of microorganisms. Huge amount of research is going on in developing hygiene products that do not initiate microbial growth. The objective of the present work is to produce antibacterial cellulose pulp by depositing silver nanopowder on the cellulose fiber. The silver nanoparticles used were of less than 100 nm in size and were characterised using transmission electron microscopy and X-ray powder diffraction studies. Antibacterial activity of the functionalized cellulose pulp was proved by JIS L 1902 method. The in-vitro cytotoxicity, in-vivo vaginal irritation and intracutaneous reactivity studies were done with silver nanopowder incorporated cellulose pulp for introducing a new value added product to the market. Cytotoxicity evaluation suggested that the silver nanoparticle incorporated cellulose pulp is non-cytotoxic. No irritation and skin sensitization were identified in animals tested with specific extracts prepared from the test material in the in-vivo experiments. The results indicated that the silver nanopowder incorporated cellulose pulp meets the requirements of the standard practices recommended for evaluating the biological reactivity and has good biocompatibility, hence can be classified as a safe hygiene product. 457. Enhanced cellulose degradation using cellulase-nanosphere complexes. Directory of Open Access Journals (Sweden) Craig Blanchette Full Text Available Enzyme catalyzed conversion of plant biomass to sugars is an inherently inefficient process, and one of the major factors limiting economical biofuel production. This is due to the physical barrier presented by polymers in plant cell walls, including semi-crystalline cellulose, to soluble enzyme accessibility. In contrast to the enzymes currently used in industry, bacterial cellulosomes organize cellulases and other proteins in a scaffold structure, and are highly efficient in degrading cellulose. To mimic this clustered assembly of enzymes, we conjugated cellulase obtained from Trichoderma viride to polystyrene nanospheres (cellulase:NS and tested the hydrolytic activity of this complex on cellulose substrates from purified and natural sources. Cellulase:NS and free cellulase were equally active on soluble carboxymethyl cellulose (CMC; however, the complexed enzyme displayed a higher affinity in its action on microcrystalline cellulose. Similarly, we found that the cellulase:NS complex was more efficient in degrading natural cellulose structures in the thickened walls of cultured wood cells. These results suggest that nanoparticle-bound enzymes can improve catalytic efficiency on physically intractable substrates. We discuss the potential for further enhancement of cellulose degradation by physically clustering combinations of different glycosyl hydrolase enzymes, and applications for using cellulase:NS complexes in biofuel production. 458. Microbial fuel cells using Cellulomonas spp. with cellulose as fuel. Science.gov (United States) Takeuchi, Yuya; Khawdas, Wichean; Aso, Yuji; Ohara, Hitomi 2017-03-01 Cellulomonas fimi, Cellulomonas biazotea, and Cellulomonas flavigena are cellulose-degrading microorganisms chosen to compare the degradation of cellulose. C. fimi degraded 2.5 g/L of cellulose within 4 days, which was the highest quantity among the three microorganisms. The electric current generation by the microbial fuel cell (MFC) using the cellulose-containing medium with C. fimi was measured over 7 days. The medium in the MFC was sampled every 24 h to quantify the degradation of cellulose, and the results showed that the electric current increased with the degradation of cellulose. The maximum electric power generated by the MFC was 38.7 mW/m(2), and this numeric value was 63% of the electric power generated by an MFC with Shewanella oneidensis MR-1, a well-known current-generating microorganism. Our results showed that C. fimi was an excellent candidate to produce the electric current from cellulose via MFCs. 459. Mass spectrometric studies of fast pyrolysis of cellulose Energy Technology Data Exchange (ETDEWEB) Degenstein, John; Hurt, Matt; Murria, Priya; Easton, McKay; Choudhari, Harshavardhan; Yang, Linan; Riedeman, James; Carlsen, Mark; Nash, John; Agrawal, Rakesh; Delgass, W.; Ribeiro, Fabio; Kenttämaa, Hilkka 2015-01-01 A fast pyrolysis probe/linear quadrupole ion trap mass spectrometer combination was used to study the primary fast pyrolysis products (those that first leave the hot pyrolysis surface) of cellulose, cellobiose, cellotriose, cellotetraose, cellopentaose, and cellohexaose, as well as of cellobiosan, cellotriosan, and cellopentosan, at 600°C. Similar products with different branching ratios were found for the oligosaccharides and cellulose, as reported previously. However, identical products (with the exception of two) with similar branching ratios were measured for cellotriosan (and cellopentosan) and cellulose. This result demonstrates that cellotriosan is an excellent small-molecule surrogate for studies of the fast pyrolysis of cellulose and also that most fast pyrolysis products of cellulose do not originate from the reducing end. Based on several observations, the fast pyrolysis of cellulose is suggested to initiate predominantly via two competing processes: the formation of anhydro-oligosaccharides, such as cellobiosan, cellotriosan, and cellopentosan (major route), and the elimination of glycolaldehyde (or isomeric) units from the reducing end of oligosaccharides formed from cellulose during fast pyrolysis. 460. Dental glass ionomer cement reinforced by cellulose microfibers and cellulose nanocrystals Energy Technology Data Exchange (ETDEWEB) Silva, Rafael M. [Departamento de Odontologia, Universidade Federal do Vale do Jequitinhonha e Mucuri, UFVJM, Diamantina CEP: 39100-000, MG (Brazil); Centro Avançado de Avaliação e Desenvolvimento de Biomateriais, BioMat, Universidade Federal do Vale do Jequitinhonha e Mucuri, UFVJM, Diamantina CEP: 39100000, MG (Brazil); Pereira, Fabiano V., E-mail: [email protected] [Departamento de QuÃmica, Universidade Federal de Minas Gerais, UFMG, Belo Horizonte CEP: 31270-901, MG (Brazil); Mota, Felipe A.P. [Centro Avançado de Avaliação e Desenvolvimento de Biomateriais, BioMat, Universidade Federal do Vale do Jequitinhonha e Mucuri, UFVJM, Diamantina CEP: 39100-000, MG (Brazil); Watanabe, Evandro [Departamento de Odontologia Restauradora, Faculdade de Odontologia de Ribeirão Preto, USP, Ribeirão Preto CEP: 14040-904, SP (Brazil); Soares, Suelleng M.C.S. [Departamento de Odontologia, Universidade Federal do Vale do Jequitinhonha e Mucuri, UFVJM, Diamantina CEP: 39100-000, MG (Brazil); Santos, Maria Helena [Departamento de Odontologia, Universidade Federal do Vale do Jequitinhonha e Mucuri, UFVJM, Diamantina CEP: 39100-000, MG (Brazil); Centro Avançado de Avaliação e Desenvolvimento de Biomateriais, BioMat, Universidade Federal do Vale do Jequitinhonha e Mucuri, UFVJM, Diamantina CEP: 39100-000, MG (Brazil) 2016-01-01 The aim of this work was to evaluate if the addition of cellulose microfibers (CmF) or cellulose nanocrystals (CNC) would improve the mechanical properties of a commercial dental glass ionomer cement (GIC). Different amounts of CmF and CNC were previously prepared and then added to reinforce the GIC matrix while it was being manipulated. Test specimens with various concentrations of CmF or CNC in their total masses were fabricated and submitted to mechanical tests (to evaluate their compressive and diametral tensile strength, modulus, surface microhardness and wear resistance) and characterized by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), transmission electron microscopy (TEM) and Fourier transform infrared spectroscopy (FTIR). The incorporation of CmF in the GIC matrix did not greatly improve the mechanical properties of GIC. However, the addition of a small amount of CNC in the GIC led to significant improvements in all of the mechanical properties evaluated: compressive strength (increased up to 110% compared with the control group), elastic modulus increased by 161%, diametral tensile strength increased by 53%, and the mass loss decreased from 10.95 to 3.87%. Because the composites presented a considerable increase in mechanical properties, the modification of the conventional GIC with CNC can represent a new and promising dental restorative material. - Highlights: • Cellulose microfibers (CmF) and cellulose nanocrystals (CNC) were prepared. • The CmF and CNC were incorporated in commercial dental glass ionomer cement (GIC). • Small amount of CNC improved significantly all the mechanical properties evaluated. • Modified GIC with CNC can represent a new and promising dental restorative material. « 21 22 23 24 25 » « 21 22 23 24 25 » 461. On the conflicting findings of Role of Cellulose-Crystallinity in Enzume Hydrolysis of Biomass Science.gov (United States) Umesh Agarwal; Sally Ralph 2014-01-01 In the field of conversion of biomass to ethanol, an important area of research is the enzymatic hydrolysis of cellulose. Once cellulose is converted to glucose, it can be easily fermented to ethanol. As the cellulosic ethanol technology stands now, costly pretreatments and high dosages of cellulases are needed to achieve complete hydrolysis of the cellulose fraction... 462. Direct fermentation of cellulose to ethanol by a cellulolytic filamentous fungus, monilia sp Energy Technology Data Exchange (ETDEWEB) Gong, C.S.; Maun, C.M.; Tsao, G.T. 1981-01-01 Monilia, isolated from bagasse compost, utilized many polysaccharides (including cellulose) and displayed cellulase and hemicellulase activities. Monilia also fermented glucose, xylose, and cellulosic materials to ethanol. Over 60% of the solid cellulose substrate added to Monilia cultures was converted to ethanol as the major fermentation product. Thus, Monilia is a potential organism for the direct conversion of cellulosic biomass to ethanol. 463. Performance of cellulose derivatives in deep-fried battered snacks: Oil barrier and crispy properties NARCIS (Netherlands) Primo-MartÃn, C.; Sanz, T.; Steringa, D.W.; Salvador, A.; Fiszman, S.M.; Vliet, T. van 2010-01-01 The performance of batters containing cellulose derivatives (methyl cellulose (A4M), three hydroxypropylmethyl celluloses (E4M, F4M and K4M) with different degree of hydroxypropyl and/or methyl substitution and carboxymethyl cellulose (CMC)) to produce crispy deep-fried snacks crusts was studied by 464. Performance of cellulose derivatives in deep-fried battered snacks: Oil barrier and crispy properties NARCIS (Netherlands) Primo-MartÃn, C.; Sanz, T.; Steringa, D.W.; Salvador, A.; Fiszman, S.M.; Vliet, T. van 2010-01-01

The performance of batters containing cellulose derivatives (methyl cellulose (A4M), three hydroxypropylmethyl celluloses (E4M, F4M and K4M) with different degree of hydroxypropyl and/or methyl substitution and carboxymethyl cellulose (CMC)) to produce crispy deep-fried snacks crusts was studied by 465. Detección de eventos en imagen de actividad neuronal para su uso en técnicas de estimulación dependiente de actividad OpenAIRE Taboada Pérez, Lourdes 2015-01-01 Este Proyecto Final de Carrera se sitúa dentro de las lÃneas de investigación desarrolladas por el Grupo de Neurocomputación Biológica (GNB) de la Escuela Politécnica Superior de la UAM. Los experimentos y estudios previos realizados por el GNB han servido como base y punto de partida para realizarlo. En este proyecto se desarrollarán algoritmos para detectar eventos significativos en la actividad de neuronas individuales empleando técnicas de tratamiento de imagen. Se pretende que estos a... 466. Cellulose nanowhiskers and nanofibers from biomass for composite applications Science.gov (United States) Wang, Tao 2011-12-01 Biological nanocomposites such as plant cell wall exhibit high mechanical properties at a light weight. The secret of the rigidity and strength of the cell wall lies in its main structural component -- cellulose. Native cellulose exists as highly-ordered microfibrils, which are just a few nanometers wide and have been found to be stiffer than many synthetic fibers. In the quest for sustainable development around the world, using cellulose microfibrils from plant materials as renewable alternatives to conventional reinforcement materials such as glass fibers and carbon fibers is generating particular interest. In this research, by mechanical disintegration and by controlled chemical hydrolysis, both cellulose nanofibers and nanowhiskers were extracted from the cell wall of an agricultural waste, wheat straw. The reinforcement performances of the two nanofillers were then studied and compared using the water-soluble polyvinyl alcohol (PVOH) as a matrix material. It was found that while both of these nanofillers could impart higher stiffness to the polymer, the nanofibers from biomass were more effective in composite reinforcement than the cellulose crystals thanks to their large aspect ratio and their ability to form interconnected network structures through hydrogen bonding. One of the biggest challenges in the development of cellulose nanocomposites is achieving good dispersion. Because of the high density of hydroxyl groups on the surface of cellulose, it remains a difficult task to disperse cellulose nanofibers in many commonly used polymer matrices. The present work addresses this issue by developing a water-based route taking advantage of polymer colloidal suspensions. Combining cellulose nanofibers with one of the most important biopolymers, poly(lactic acid) (PLA), we have prepared nanocomposites with excellent fiber dispersion and improved modulus and strength. The bio-based nanocomposites have a great potential to serve as light-weight structural materials 467. Biological evaluation of nanosilver incorporated cellulose pulp for hygiene products Energy Technology Data Exchange (ETDEWEB) Kavitha Sankar, P.C.; Ramakrishnan, Reshmi; Rosemary, M.J., E-mail: [email protected] 2016-04-01 Cellulose pulp has a visible market share in personal hygiene products such as sanitary napkins and baby diapers. However it offers good surface for growth of microorganisms. Huge amount of research is going on in developing hygiene products that do not initiate microbial growth. The objective of the present work is to produce antibacterial cellulose pulp by depositing silver nanopowder on the cellulose fiber. The silver nanoparticles used were of less than 100 nm in size and were characterised using transmission electron microscopy and X-ray powder diffraction studies. Antibacterial activity of the functionalized cellulose pulp was proved by JIS L 1902 method. The in-vitro cytotoxicity, in-vivo vaginal irritation and intracutaneous reactivity studies were done with silver nanopowder incorporated cellulose pulp for introducing a new value added product to the market. Cytotoxicity evaluation suggested that the silver nanoparticle incorporated cellulose pulp is non-cytotoxic. No irritation and skin sensitization were identified in animals tested with specific extracts prepared from the test material in the in-vivo experiments. The results indicated that the silver nanopowder incorporated cellulose pulp meets the requirements of the standard practices recommended for evaluating the biological reactivity and has good biocompatibility, hence can be classified as a safe hygiene product. - Highlights: • Different amounts of silver nanoparticles (0.2 g–0.4 g/napkin) were added to cellulose pulp. • The silver nanoparticle incorporated cellulose pulp was proved to be antibacterial by JIS L 1902 method. • The minimum concentration of silver required for antibacterial activity with no cytotoxicity has been found out. • In-vivo vaginal irritation and intracutaneous reactivity studies confirmed the biocompatibility of the material. 468. Morphological structure of Gluconacetobacter xylinus cellulose and cellulose-based organic-inorganic composite materials Science.gov (United States) Smyslov, R. Yu; Ezdakova, K. V.; Kopitsa, G. P.; Khripunov, A. K.; Bugrov, A. N.; Tkachenko, A. A.; Angelov, B.; Pipich, V.; Szekely, N. K.; Baranchikov, A. E.; Latysheva, E.; Chetverikov, Yu O.; Haramus, V. 2017-05-01 Scanning electron microscopy, ultra-small-angle neutron scattering (USANS), small-angle neutron and X-ray scattering (SANS and SAXS), as well as low-temperature nitrogen adsorption, were used in the studies of micro- and mesostructure of polymer matrix prepared from air-dry preliminarily disintegrated cellulose nano-gel film (synthesized by Gluconacetobacter xylinus) and the composites based on this bacterial cellulose. The composites included ZrO2 nanoparticles, Tb3+ in the form of low molecular weight salt and of metal-polymer complex with poly(vinylpyrrolydone)-poly(methacryloyl-o-aminobenzoic acid) copolymer. The combined analysis of the data obtained allowed revealing three levels of fractal organization in mesostructure of G. xylinus cellulose and its composites. It was shown that both the composition and an aggregation state of dopants have a significant impact on the structural characteristics of the organic-inorganic composites. The composites containing Tb3+ ions demonstrate efficient luminescence; its intensity is an order of magnitude higher in the case of the composites with the metal-polymer complex. It was found that there is the optimal content of ZrO2 nanoparticles in composites resulting in increased Tb3+ luminescence. 469. Comparative Structural and Computational Analysis Supports Eighteen Cellulose Synthases in the Plant Cellulose Synthesis Complex. Science.gov (United States) Nixon, B Tracy; Mansouri, Katayoun; Singh, Abhishek; Du, Juan; Davis, Jonathan K; Lee, Jung-Goo; Slabaugh, Erin; Vandavasi, Venu Gopal; O'Neill, Hugh; Roberts, Eric M; Roberts, Alison W; Yingling, Yaroslava G; Haigler, Candace H 2016-06-27 A six-lobed membrane spanning cellulose synthesis complex (CSC) containing multiple cellulose synthase (CESA) glycosyltransferases mediates cellulose microfibril formation. The number of CESAs in the CSC has been debated for decades in light of changing estimates of the diameter of the smallest microfibril formed from the β-1,4 glucan chains synthesized by one CSC. We obtained more direct evidence through generating improved transmission electron microscopy (TEM) images and image averages of the rosette-type CSC, revealing the frequent triangularity and average cross-sectional area in the plasma membrane of its individual lobes. Trimeric oligomers of two alternative CESA computational models corresponded well with individual lobe geometry. A six-fold assembly of the trimeric computational oligomer had the lowest potential energy per monomer and was consistent with rosette CSC morphology. Negative stain TEM and image averaging showed the triangularity of a recombinant CESA cytosolic domain, consistent with previous modeling of its trimeric nature from small angle scattering (SAXS) data. Six trimeric SAXS models nearly filled the space below an average FF-TEM image of the rosette CSC. In summary, the multifaceted data support a rosette CSC with 18 CESAs that mediates the synthesis of a fundamental microfibril composed of 18 glucan chains. 470. Effects of Soybean Oil Modified Cellulose Fibril and Organosilane Modified Cellulose Fibril on Crystallization of Polypropylene Directory of Open Access Journals (Sweden) Sarit Thanomchat 2015-01-01 Full Text Available Soybean oil modified cellulose fibril (Oil-g-CF and organosilane modified cellulose fibril (Silane-g-CF were prepared using maleinized soybean oil and hexadecyltrimethoxysilane, respectively. Thus obtained modified cellulose fibril was added to polypropylene by a simple melt mixing on a hotplate. PP/modified CF composites with 4.0 wt% filler content were prepared. The composites were subject to a polarized optical microscope to investigate particle dispersion, supramolecular morphology, and crystallization behavior. It was found that Silane-g-CF exhibited smaller particle sizes with better particle distribution when compared to Oil-g-CF. In addition, the etched composite samples unveiled an increase in a number of spherulite crystals as well as a decrease in the spherulite size. The nonisothermal crystallization study of composites revealed that both Oil-g-CF and Silane-g-CF were capable of nucleating PP by facilitating faster crystallization process and raising the number of spherulites. The DSC results indicated that Silane-g-CF was able to perform a more effective nucleation than Oil-g-CF, judged by a higher crystallization temperature. Moreover, PP composites containing Oil-g-CF and Silane-g-CF had higher crystallinity by 7% and 10%, for the first and the latter, respectively, when compared to neat PP. 471. Modelo de integración de las actividades de gestión de la guÃa del pmbok, con las actividades de ingenierÃa, en proyectos de desarrollo de software OpenAIRE Rojas Contreras., Mauricio Eduardo; Villamizar, Luis Alberto Esteban; Orjuela Duarte., Ailin 2011-01-01 En forma general, los proyectos están estructurados en actividades de tipo técnicas y de gestión. En forma especÃfica, los proyectos de desarrollo de software en la gran mayorÃa de casos se han centrado en las actividades técnicas dejando a un lado las actividades de gestión del proyecto, lo cual incrementa el riesgo de no cumplir con indicadores de calidad del proyecto como son el alcance, el tiempo y los costos. En este trabajo se adaptan los fundamentos de la dirección de proyectos especif... 472. Cellulose nanocrystal reinforced oxidized natural rubber nanocomposites. Science.gov (United States) Mariano, Marcos; El Kissi, Nadia; Dufresne, Alain 2016-02-10 Natural rubber (NR) latex particles were oxidized using KMnO4 as oxidant to promote the insertion of hydroxyl groups in the surface polyisoprene chains. Different degrees of oxidation were investigated. Both unoxidized and oxidized NR (ONR) latex were used to prepare nanocomposite films reinforced with cellulose nanocrystals (CNCs) by casting/evaporation. The oxidation of NR was carried out to promote chemical interactions between the hydroxyl groups of ONR with those of CNCs through hydrogen bonding. The effect of the degree of oxidation of the NR latex on the rheological behavior of CNC/NR and CNC/ONR suspensions, as well as on the mechanical, swelling and thermal properties of ensuing nanocomposites was investigated. Improved properties were observed for intermediate degrees of oxidation but they were found to degrade for higher oxidation levels. 473. Third Generation Biofuels via Direct Cellulose Fermentation Directory of Open Access Journals (Sweden) David B. Levin 2008-07-01 Full Text Available Consolidated bioprocessing (CBP is a system in which cellulase production, substrate hydrolysis, and fermentation are accomplished in a single process step by cellulolytic microorganisms. CBP offers the potential for lower biofuel production costs due to simpler feedstock processing, lower energy inputs, and higher conversion efficiencies than separate hydrolysis and fermentation processes, and is an economically attractive near-term goal for “third generation†biofuel production. In this review article, production of third generation biofuels from cellulosic feedstocks will be addressed in respect to the metabolism of cellulolytic bacteria and the development of strategies to increase biofuel yields through metabolic engineering. 474. Novel enzymes for the degradation of cellulose Directory of Open Access Journals (Sweden) Horn Svein 2012-07-01 Full Text Available Abstract The bulk terrestrial biomass resource in a future bio-economy will be lignocellulosic biomass, which is recalcitrant and challenging to process. Enzymatic conversion of polysaccharides in the lignocellulosic biomass will be a key technology in future biorefineries and this technology is currently the subject of intensive research. We describe recent developments in enzyme technology for conversion of cellulose, the most abundant, homogeneous and recalcitrant polysaccharide in lignocellulosic biomass. In particular, we focus on a recently discovered new type of enzymes currently classified as CBM33 and GH61 that catalyze oxidative cleavage of polysaccharides. These enzymes promote the efficiency of classical hydrolytic enzymes (cellulases by acting on the surfaces of the insoluble substrate, where they introduce chain breaks in the polysaccharide chains, without the need of first “extracting†these chains from their crystalline matrix. 475. The gelation of oil using ethyl cellulose. Science.gov (United States) Davidovich-Pinhas, M; Barbut, S; Marangoni, A G 2015-03-06 The characterization of the thermo-gelation mechanism and properties of ethyl cellulose/canola oil oleogels was performed using rheology and thermal analysis. Thermal analysis detected no evidence for thermal transitions contributed to secondary conformational changes, suggesting a gelation mechanism that does not involve secondary ordered structure formation. Rheological analysis demonstrated a relationship between the polymer molecular weight and the final gel strength, the cross-over behavior as well as the gel point temperature. Increasing polymer molecular weight led to an increase in final gel strength, the modulus at cross-over, and the gel point temperature. Cooling/heating rates affect gel modulus only for the low molecular weight samples. A decrease in gel strength with increasing cooling rate was detected. The cross-over temperature was not affected by the cooling/heating rates. Cooling rate also affected the gelation setting time where slow cooling rates produced a stable gel faster. 476. Cellulose nanocrystals reinforced foamed nitrile rubber nanocomposites. Science.gov (United States) Chen, Yukun; Zhang, Yuanbing; Xu, Chuanhui; Cao, Xiaodong 2015-10-05 Research on foamed nitrile rubber (NBR)/cellulose nanocrystals (CNs) nanocomposites is rarely found in the literatures. In this paper, CNs suspension and NBR latex was mixed to prepared the foamed NBR/CNs nanocomposites. We found that the CNs mainly located in the cell walls, effectively reinforcing the foamed NBR. The strong interaction between the CNs and NBR matrix restricted the mobility of NBR chains surrounding the CNs, hence increasing the crosslink density of the NBR matrix. CNs exhibited excellent reinforcement on the foamed NBR: a remarkable increase nearly 76% in the tensile strength of the foamed nanocomposites was achieved with a load of only 15 phr CNs. Enhanced mechanical properties make the foamed NBR/CNs nanocomposites a promising damping material for industrial applications with a potential to reduce the petroleum consumption. 477. Inclusion of solid particles in bacterial cellulose. Science.gov (United States) Serafica, G; Mormino, R; Bungay, H 2002-05-01 Depending upon the strain and the method of cultivation, bacterial cellulose can be reticulated filaments, pellets, or a dense, tough gel called a pellicle. The pellicular form is commonly made by surface culture, but a rotating disk bioreactor is more efficient and reduces the time of a run to about 3.5 days instead of the usual 12-20 days. Particles added to the medium as the gel is forming are trapped to form a new class of composite materials. Particles enter the films that are forming on the disks at rates depending on the size and geometry of the particle, as well as the rotational speed and concentration of the suspension. 478. Sustainable green composites of thermoplastic starch and cellulose fibers Directory of Open Access Journals (Sweden) Amnuay Wattanakornsiri 2014-04-01 Full Text Available Green composites have gained renewed interest as environmental friendly materials and as biodegradable renewable resources for a sustainable development. This review provides an overview of recent advances in green composites based on thermoplastic starch (TPS and cellulose fibers. It includes information about compositions, preparations, and properties of starch, cellulose fibers, TPS, and green composites based on TPS and cellulose fibers. Introduction and production of these recyclable composites into the material market would be important for environmental sustainability as their use can decrease the volume of petroleum derived plastic waste dumps. Green composites are comparable cheap and abundant, but further research and development is needed for a broader utilization. 479. Impact of cellulose ethers on the cement paste microstructure OpenAIRE Pourchez, Jérémie; Grosseau, Philippe; Rouèche-Pourchez, Emilie; Debayle, Johan; Pinoli, Jean-Charles; Maire, Eric; Boller, Elodie; Parra-Denis, Estelle 2007-01-01 ISBN = 3-87264-022-4 7 pages; International audience; Complementary investigation tools (2D and 3D observations by optical microscopy and fast X-ray microtomography and then image analysis) were developed in order to examine the effects of cellulose ethers on the cement paste microstructure. The obtained results show that the presence of cellulose ether may induce an increase of both 50-250 µm-diameter air voids. The chemistry of the cellulose ethers appears as a main controlling factor of th... 480. Fabrication of Piezoelectric Cellulose Paper and Audio Application Institute of Scientific and Technical Information of China (English) Jung-Hwan Kim; Sungryul Yun; Joo-Hyung Kim; Jaehwan Kim 2009-01-01 We report the fabrication process of piezoelectric cellulose paper and the enhancement method of its piezoelectric property.Stretching method with different wet-drawing ratios was introduced to increase the piezoelectric property of cellulose paper during regeneration process. It is observed that the Young's modulus and the piezoelectric charge constants are very dependent on the drawing ratio and the direction of nanofibrils of piezoelectric paper. Using the enhanced piezoelectric property, we prove that the flexible regenerated piezoelectric cellulose can be applied to the potential acoustic applications such as thin piezoelectric paper speaker. « 21 22 23 24 25 » « 21 22 23 24 25 » 481. Preliminary Research on Structure and Properties of Nano-cellulose Institute of Scientific and Technical Information of China (English)

æ— 2007-01-01 The structure of bacterial cellulose (BC) produced by Acetobacter xylinum NUST4 (A.xylinum NUST4) under static (SBC) and shake culture condition (ABC) was studied by means of transmission electron microscopic (TEM), X-ray diffraction (XRD) and Fourier transform-infrared spectrum (FT-IR). It was revealed that BC is â… crystal cellulose and the proportion of cellulose â… Î± exceeds 80% and BC diameter is 10-80 nm.Mechanical properties and water absorption capacity were also determined. These properties could result from crystalline and nanometer structure of BC. 482. GRAFTING OF HUMIC ACID ONTO COTTON CELLULOSE (â…¡) Institute of Scientific and Technical Information of China (English) CHEN Qi; ZHANG Dehe 1988-01-01 Cotton cellulose reacted with epichlorohydrin under the catalytic action of HClO4 and H2O to form 3-chloro-2-hydroxypropyl ether with a substitution degree of 0.61. The chlorine-containing product was treated with aliphatic diamines (ethylenediamine, propylenediamine, etc.) to produce nitrogen-containing cellulose which further reacted with humic acid to give black fiberous graft cellulose. This product contains 27-35%humic acid, 0.90 meq/g acidic groups, possesses 0.49 meq/g Cu2 +-complexing capacity and good mechanical strength, and can be used under pH12. 483. Copper removal using electrosterically stabilized nanocrystalline cellulose. Science.gov (United States) Sheikhi, Amir; Safari, Salman; Yang, Han; van de Ven, Theo G M 2015-06-03 Removal of heavy metal ions such as copper using an efficient and low-cost method with low ecological footprint is a critical process in wastewater treatment, which can be achieved in a liquid phase using nanoadsorbents such as inorganic nanoparticles. Recently, attention has turned toward developing sustainable and environmentally friendly nanoadsorbents to remove heavy metal ions from aqueous media. Electrosterically stabilized nanocrystalline cellulose (ENCC), which can be prepared from wood fibers through periodate/chlorite oxidation, has been shown to have a high charge content and colloidal stability. Here, we show that ENCC scavenges copper ions by different mechanisms depending on the ion concentration. When the Cu(II) concentration is low (C0≲200 ppm), agglomerates of starlike ENCC particles appear, which are broken into individual starlike entities by shear and Brownian motion, as evidenced by photometric dispersion analysis, dynamic light scattering, and transmission electron microscopy. On the other hand, at higher copper concentrations, the aggregate morphology changes from starlike to raftlike, which is probably due to the collapse of protruding dicarboxylic cellulose (DCC) chains and ENCC charge neutralization by copper adsorption. Such raftlike structures result from head-tohead and lateral aggregation of neutralized ENCCs as confirmed by transmission electron microscopy. As opposed to starlike aggregates, the raftlike structures grow gradually and are prone to sedimentation at copper concentrations C0≳500 ppm, which eliminates a costly separation step in wastewater treatment processes. Moreover, a copper removal capacity of ∼185 mg g(-1) was achieved thanks to the highly charged DCC polyanions protruding from ENCC. These properties along with the biorenewability make ENCC a promising candidate for wastewater treatment, in which fast, facile, and low-cost removal of heavy metal ions is desired most. 484. The mathematical model of dye diffusion and adsorption on modified cellulose with triazine derivatives containing cationic and anionic groups Science.gov (United States) Xie, K.; Hou, A.; Chen, Y. 2008-02-01 Cellulose fabric is chemically modified with the compounds containing cationic and anionic groups. The molecular chains of modified cellulose have both cationic and anionic groups. Dye diffusion properties on modified cellulose are discussed. The dye adsorption and diffusion on modified cellulose are higher than those on unmodified cellulose. The diffusion properties of dyes at different temperature are discussed. Compared with unmodified cellulose, the diffusion processing of dyes in the modified cotton cellulose shows significant change. 485. INFLUENCIA DE LAS BACTERIAS PSICRÓTROFAS EN LA ACTIVIDAD PROTEOLÃTICA DE LA LECHE Directory of Open Access Journals (Sweden) C F Novoa 2007-01-01 Full Text Available La refrigeración de la leche reduce el ritmo de multiplicación y actividad de los microorganismos,pero ha generado nuevos problemas relacionados con el crecimiento y la actividad de losmicroorganismos psicrótrofos, que son aquellos que crecen a temperaturas inferiores a 7°C, independientementede su temperatura óptima. Estos microorganismos producen enzimas termoestablesque degradan algunos componentes de la leche deteriorando su calidad y la de sus derivados,y disminuyendo los rendimientos queseros. Con el fin de evaluar la actividadproteolÃtica de las bacterias psicrótrofas sobre las caseÃnas y su relación con la temperatura ytiempo de almacenamiento de la leche, se inocularon diferentes lotes de leche con este tipo debacterias, hasta obtener recuentos de 104 Y 105 unidades formadoras de colonia por mililitro(ufc/ml; como control se utilizó leche que no recibió inoculación con recuento de psicrótrofos de103 ufc/ml. Después de almacenarla leche a4 y 7 °C durante tres y seis dÃas, se evaluó la actividadproteolÃtica sobre las caseÃnas. Al almacenar leche durante tres dÃas a 4 y 7°C, no se presentó actividadproteolÃtica cuando el recuento inicial de psicrótrofos era del orden de 103 ufc/ml, mientrasque cuando dicho recuento fue superior a 104 ufc/ml se observó actividad proteolÃtica, siendomás intensa a 7 °C que a 4 "C. Con almacenamiento de seis dÃas, solamente la leche conservada a4°C con recuento inicial de 103 ufc/ml no presentó actividad proteolÃtica, los demás tratamientosmostraron gran actividad proteolÃtica sobre la fracción de caseÃnas aumentando dicha actividad amedida que aumenta el grado de contaminación. 486. Actividad fÃsica y hábitos de salud en estudiantes universitarios argentinos Directory of Open Access Journals (Sweden) Guillermo Pérez Ugidos Full Text Available Objetivo: El deterioro de los hábitos saludables en los jóvenes, particularmente universitarios, justifica su investigación en dichas poblaciones. El objetivo del presente estudio es analizar los niveles de actividad fÃsica en estudiantes de la Universidad Nacional de La Matanza (Argentina, intentando describir grupos homogéneos según caracterÃsticas demográficas, de hábitos de salud y de percepción de bienestar, e identificando el nivel de actividad fÃsica que mejor describa a cada uno de los grupos. MetodologÃa: Participaron 554 estudiantes (281 varones y 273 mujeres de distintas carreras a los que se aplicó el Cuestionario Global de Actividad FÃsica (GPAQ y un instrumento sobre hábitos de salud, percepción de felicidad y diversas variables demográficas. Se calcularon medidas de tendencia central y variabilidad, asà como los percentiles P25 y P75, para todas las variables. Se realizó una segmentación mediante análisis de clusters jerárquico, con un análisis de factores previo. Resultados: El 79,8% de los estudiantes, y el 97,2% de aquellos que cursaban Educación FÃsica cumplÃan con las recomendaciones de realización de actividad fÃsica. Los alumnos que se identificaban con un nivel de actividad fÃsica alto eran los que cursaban en turno diurno, no consumÃan tabaco, alcohol ni drogas, no trabajaban, no tenÃan hijos ni pareja estable, y poseÃan un nivel socio-económico medio. Conclusiones: Se sugiere la necesidad de una sólida intervención educativa por parte de las universidades para fomentar hábitos saludables y la realización regular de actividad fÃsica, ya que tienen una responsabilidad social primaria respecto a estas problemáticas. 487. Cellulose synthase complexes act in a concerted fashion to synthesize highly aggregated cellulose in secondary cell walls of plants. Science.gov (United States) Li, Shundai; Bashline, Logan; Zheng, Yunzhen; Xin, Xiaoran; Huang, Shixin; Kong, Zhaosheng; Kim, Seong H; Cosgrove, Daniel J; Gu, Ying 2016-10-04 Cellulose, often touted as the most abundant biopolymer on Earth, is a critical component of the plant cell wall and is synthesized by plasma membrane-spanning cellulose synthase (CESA) enzymes, which in plants are organized into rosette-like CESA complexes (CSCs). Plants construct two types of cell walls, primary cell walls (PCWs) and secondary cell walls (SCWs), which differ in composition, structure, and purpose. Cellulose in PCWs and SCWs is chemically identical but has different physical characteristics. During PCW synthesis, multiple dispersed CSCs move along a shared linear track in opposing directions while synthesizing cellulose microfibrils with low aggregation. In contrast, during SCW synthesis, we observed swaths of densely arranged CSCs that moved in the same direction along tracks while synthesizing cellulose microfibrils that became highly aggregated. Our data support a model in which distinct spatiotemporal features of active CSCs during PCW and SCW synthesis contribute to the formation of cellulose with distinct structure and organization in PCWs and SCWs of Arabidopsis thaliana This study provides a foundation for understanding differences in the formation, structure, and organization of cellulose in PCWs and SCWs. 488. Efecto dun estÃmulo potenciador na actividade neuronal da corteza motora, putamen e amÃgdala OpenAIRE Montes Lourido, MarÃa del Pilar 2016-01-01 RESUMO: O presente traballo de investigación propón describir as caracterÃsticas da actividade neuronal da corteza premotora, o putamen e a amÃgdala durante a realización dunha tarefa visuomotora que require dun movemento para recibir unha recompensa. O obxectivo deste traballo é estudar a influenza da presentación de estimulación visual, xunto coa presencia ou ausencia dun estÃmulo potenciador, na actividade neuronal das citadas áreas. Para realizar este estudo rexistrouse a actividade unita... 489. Niveles de actividad fÃsica, beneficios, barreras y autoeficacia en un grupo de empleados oficiales OpenAIRE MARÃA MERCEDES BECERRA MARTÃNEZ; LUZ PATRICIA DÃAZ HEREDIA 2008-01-01 Objetivo: determinar la relación entre el nivel de actividad fÃsica y la percepción de los beneficios, las barreras y la autoeficacia en un grupo de empleados de 18 a 65 años con factores de riesgo cardiovascular. Método: estudio de tipo cuantitativo, descriptivo, correlacional. Para evaluar la actividad fÃsica se utilizó el Cuestionario Internacional de Actividad FÃsica (IPAQ) versión larga y para la evaluación de la escala de barreras, beneficios y autoeficacia se empleó el cuestionario de ... 490. El impacto del diseño de actividades en el plagio de Internet en educación superior OpenAIRE Gómez Espinosa, MarÃa; Francisco, Virginia; Moreno Ger, Pablo 2016-01-01 El objetivo de este trabajo es comprender mejor la naturaleza del plagio en la Educación Superior. Analizamos una serie de actividades en un curso on-line de nivel universitario, con el objetivo de encontrar qué tareas llevan más naturalmente al plagio. Este análisis concluye que las actividades que tienen una menor tasa de plagio son actividades que fomentan la participación, la originalidad y la creatividad. Posteriormente, reformulamos la tarea que presenta la mayor tasa de plagio... 491. El impacto del diseño de actividades en el plagio de Internet en educación superior OpenAIRE 2016-01-01 El objetivo de este trabajo es comprender mejor la naturaleza del plagio en la Educación Superior. Analizamos una serie de actividades en un curso on-line de nivel universitario, con el objetivo de encontrar qué tareas llevan más naturalmente al plagio. Este análisis concluye que las actividades que tienen una menor tasa de plagio son actividades que fomentan la participación, la originalidad y la creatividad. Posteriormente, reformulamos la tarea que presenta la mayor tasa de plagio, teniend... 492. MODULACION DE LA ACTIVIDAD SINAPTICA GABAERGICA POR COACTIVACION DE RECEPTORES PARA ENDOCANABINODES Y ACETILCOLINA EN EL HIPOCAMPO OpenAIRE COUVE PEREZ, ALEJANDRO 2010-01-01 El balance entre la actividad sináptica excitatoria e inhibitoria es fundamental para la regulación de la excitabilidad neuronal y plasticidad sináptica en el Sistema Nervioso Central (SNC) y periférico. Debido a que el control de la excitabilidad neuronal en el SNC es altamente dependiente del nivel de inhibición establecido por la actividad de interneuronas GABAérgicas, el estudio de los fenómenos que se encuentran regulando la actividad sináptica en este tipo de neuronas res... 493. ACONDICIONAMIENTO DE LAS ÃREAS PROTEGIDAS PARA EL DESARROLLO DE ACTIVIDADES DE OCIO Y RECREACIÓN OpenAIRE Francisco Orgaz Agüera 2013-01-01 Las áreas protegidas son zonas potenciales para la realización de actividades de ocio y recreación en contacto con la naturaleza, si bien, para ello es necesario que se desarrolle la actividad de forma sostenible. El objetivo de este artÃculo es presentar las diversas acciones mÃnimas que se deben de ejecutar para acondicionar tales áreas, con la finalidad de que las actividades se desarrollen de forma adecuada. La metodologÃa empleada ha consistido en un trabajo de campo en diversas áreas pr... 494. Biomimetic Mineralization on a Macroporous Cellulose-Based Matrix for Bone Regeneration OpenAIRE 2013-01-01 The aim of this study is to investigate the biomimetic mineralization on a cellulose-based porous matrix with an improved biological profile. The cellulose matrix was precalcified using three methods: (i) cellulose samples were treated with a solution of calcium chloride and diammonium hydrogen phosphate; (ii) the carboxymethylated cellulose matrix was stored in a saturated calcium hydroxide solution; (iii) the cellulose matrix was mixed with a calcium silicate solution in order to introduce ... 495. EFFECTS OF DILUTE ACID HYDROLYSIS ON COMPOSITION AND STRUCTURE OF CELLULOSE IN EULALIOPSIS BINATA OpenAIRE Jiebin Tang; Kefu Chen; Jun Xu; Jun Li; Chuanshan Zhao 2011-01-01 Dilute sulfuric acid hydrolysis was performed before the isolation of cellulose from Eulaliopsis binata. And then, the effects of dilute acid hydrolysis on composition and structure of the cellulose was studied in detail. The results indicated that hemicellulose was dissolved mostly and that the lignin-hemicellulose-cellulose interactions were also partially disrupted during the dilute acid hydrolysis. Cellulose in Eulaliopsis binata was identified as the cellulose I allomorph with low crysta... 496. Screening of the effective cellulose-degradable strain and its application in the production of cellulose bioethanol Institute of Scientific and Technical Information of China (English) Peng-fei Gao; Dai-di Fan; Pei Ma; Yan-e Luo; Xiao-xuan Ma; Chen-hui Zhu; Jun-feng Hui 2009-01-01 Strains from the cellulose-containing environment were collected. Primary screening(by filter-paper Hutchison solid culture medium and sodium carboxymethylcellulose solid culture medium) and reelection(by filter-paper inorganic salt culture medium and sodium carboxymethylcellulosc Congo red coltnre medium) indicated that five strains obtained were best suited for high performance cellulose degradation. Determination of sodium carboxymethylcellulose activity(CMCA) and filter paper activity(FPA) was accomplished for each of the five. The strongest of the five in CMCA and FPA was applied to the production of cellulose bioethanol by separate hydrolysis and fermentation(SHF) and simultaneous saccharification and fermentation(SSF) respectively. 497. Usos de POR y PARA: puesta en práctica de una actividad comunicativa Directory of Open Access Journals (Sweden) Elena GandÃa GarcÃa 2009-01-01 Full Text Available El enfoque comunicativo tiene como objetivo principal el desarrollo de la competencia comunicativa y no sólo el de la lingüÃstica. Este enfoque se centra en el estudio del uso de la lengua como una forma de relación que ponen en práctica los seres humanos. El alumno pasa a ser el centro del proceso de enseà ±anza-aprendizaje y se llevan a cabo evaluaciones para determinar sus necesidades y caracterÃsticas. La puesta en práctica de actividades comunicativas aumenta la confianza del alumno y, por tanto,su producción en la lengua extranjera, que facilitará su aprendizaje de un modo natural.Palabras clave: enfoque comunicativo, competencia comunicativa, por, para, actividad comunicativa. 498. Sobre la imputabilidad del daño en materia de responsabilidad por las actividades peligrosas Directory of Open Access Journals (Sweden) Fabricio Mantilla-Espinosa 2010-03-01 Full Text Available Este artÃculo es un análisis crÃtico de ciertas posiciones doctrinales que pretenden aplicar en Colombia teorÃas sobre el nexo causal, elaboradas por la doctrina francesa. Se trata de explicar, de esta manera, algunas particularidades del régimen colombiano de responsabilidad  por  las actividades peligrosas.  De aceptarse en la jurisprudencia colombiana dichas posiciones se desfigurarÃa completamente el régimen especial de responsabilidad por las actividades peligrosas. Desfiguración que conllevarÃa, en la práctica, a una confusión con el régimen general de responsabilidad por culpa. 499. Influencia de la actividad fÃsica en la salud humana Directory of Open Access Journals (Sweden) Alonso MartÃn, Juan Manual 2000-02-01 Full Text Available Not available El ejercicio fÃsico es un agente importante en el mantenimiento de la salud y en la prevención de diversas enfermedades. El cuidado en la enfermedad coronaria, la hipertensión, la diabetes, la obesidad, el cáncer, la osteoporosis y el incremento de la salud mental se han relacionado con la actividad fÃsica y el ejercicio. En este artÃculo se resumen los efectos de la realización de deporte en las enfermedades más comunes de la sociedad actual. Sin embargo, la mayorÃa de la población no practica actividad fÃsica. Por lo tanto, es preciso que los médicos prescriban más frecuentemente el ejercicio fÃsico. 500. Actividades creativas en Educación Musical: la composición musical grupal Directory of Open Access Journals (Sweden) Hernández Bravo, J.R. 2010-01-01 Full Text Available La educación musical es una de las áreas curriculares que contribuye de manera más decisiva al desarrollo de la creatividad en el alumnado. El aula de música, como espacio ideal para la experimentación y la manifestación libre de ideas y sentimientos, facilita la realización de actividades creativas tanto individuales como grupales. En este artÃculo se recoge un ejemplo de estas actividades en donde, a través de la elaboración en grupo de una composición musical, se constata las aportaciones creativas de cada estudiante y su contribución a la realización de una tarea musical común. « 21

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