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Sample records for cellulose synthesis inhibitory

  1. 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

  2. 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.

  3. Cellulose Synthases and Synthesis in Arabidopsis

    Institute of Scientific and Technical Information of China (English)

    Anne Endler; Staffan Persson

    2011-01-01

    Plant cell walls are complex structures composed of high-molecular-weight polysaccharides,proteins,and lignins. Among the wall polysaccharides,cellulose,a hydrogen-bonded β-1,4-linked glucan microfibril,is the main load-bearing wall component and a key precursor for industrial applications. Cellulose is synthesized by large multi-meric cellulose synthase (CesA) complexes,tracking along cortical microtubules at the plasma membrane. The only known components of these complexes are the cellulose synthase proteins. Recent studies have identified tentative interaction partners for the CesAs and shown that the migratory patterns of the CesA complexes depend on phosphorylation status. These advances may become good platforms for expanding our knowledge about cellulose synthesis in the near future. In addition,our current understanding of cellulose chain polymerization in the context of the CesA complex is discussed.

  4. Probing inhibitory effects of nanocrystalline cellulose: inhibition versus surface charge

    Science.gov (United States)

    Male, Keith B.; Leung, Alfred C. W.; Montes, Johnny; Kamen, Amine; Luong, John H. T.

    2012-02-01

    NCC derived from different biomass sources was probed for its plausible cytotoxicity by electric cell-substrate impedance sensing (ECIS). Two different cell lines, Spodoptera frugiperda Sf9 insect cells and Chinese hamster lung fibroblast V79, were exposed to NCC and their spreading and viability were monitored and quantified by ECIS. Based on the 50%-inhibition concentration (ECIS50), none of the NCC produced was judged to have any significant cytotoxicity on these two cell lines. However, NCC derived from flax exhibited the most pronounced inhibition on Sf9 compared to hemp and cellulose powder. NCCs from flax and hemp pre-treated with pectate lyase were also less inhibitory than NCCs prepared from untreated flax and hemp. Results also suggested a correlation between the inhibitory effect and the carboxylic acid contents on the NCC.

  5. 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...

  6. Characterization of Cellulose Synthesis in Plant Cells

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    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.

  7. Effect of Surface Attachment on Synthesis of Bacterial Cellulose

    Energy Technology Data Exchange (ETDEWEB)

    Evans, Barbara R [ORNL; O' Neill, Hugh Michael [ORNL

    2005-01-01

    Gluconacetobacter spp. synthesize a pure form of hydrophilic cellulose that has several industrial specialty applications. Literature reports have concentrated on intensive investigation of static and agitated culture in liquid media containing high nutrient concentrations optimized for maximal cellulose production rates. The behavior of these bacteria on semisolid and solid surfaces has not been specifically addressed. The species Gluconacetobacter hansenii was examined for cellulose synthesis and colony morphology on a range of solid supports, including cotton linters, and on media thickened with agar, methyl cellulose, or gellan. The concentration and chemical structure of the thickening agent were found to be directly related to the formation of contiguous cellulose pellicules. Viability of the bacteria following freezer storage was improved when the bacteria were frozen in their cellulose pellicules.

  8. Inhibitory effect of vanillin on cellulase activity in hydrolysis of cellulosic biomass.

    Science.gov (United States)

    Li, Yun; Qi, Benkun; Wan, Yinhua

    2014-09-01

    Pretreatment of lignocellulosic material produces a wide variety of inhibitory compounds, which strongly inhibit the following enzymatic hydrolysis of cellulosic biomass. Vanillin is a kind of phenolics derived from degradation of lignin. The effect of vanillin on cellulase activity for the hydrolysis of cellulose was investigated in detail. The results clearly showed that vanillin can reversibly and non-competitively inhibit the cellulase activity at appropriate concentrations and the value of IC50 was estimated to be 30 g/L. The inhibition kinetics of cellulase by vanillin was studied using HCH-1 model and inhibition constants were determined. Moreover, investigation of three compounds with similar structure of vanillin on cellulase activity demonstrated that aldehyde group and phenolic hydroxyl groups of vanillin had inhibitory effect on cellulase. These results provide valuable and detailed information for understanding the inhibition of lignin derived phenolics on cellulase.

  9. Cellulose nanocrystals: synthesis, functional properties, and applications

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    George J

    2015-11-01

    Full Text Available 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 are biodegradable and renewable in nature and hence they serve as a sustainable and environmentally friendly material for most applications. These nanocrystals are basically hydrophilic in nature; however, they can be surface functionalized to meet various challenging requirements, such as the development of high-performance nanocomposites, using hydrophobic polymer matrices. Considering the ever-increasing interdisciplinary research being carried out on cellulose nanocrystals, this review aims to collate the knowledge available about the sources, chemical structure, and physical and chemical isolation procedures, as well as describes the mechanical, optical, and rheological properties, of cellulose nanocrystals. Innovative applications in diverse fields such as biomedical engineering, material sciences, electronics, catalysis, etc, wherein these cellulose nanocrystals can be used, are highlighted. Keywords: sources of cellulose, mechanical properties, liquid crystalline nature, surface modification, nanocomposites 

  10. Pretreatment assisted synthesis and characterization of cellulose nanocrystals and cellulose nanofibers from absorbent cotton.

    Science.gov (United States)

    Abu-Danso, Emmanuel; Srivastava, Varsha; Sillanpää, Mika; Bhatnagar, Amit

    2017-03-30

    In this work, cellulose nanocrystals (CNCs) and cellulose nanofibers (CNFs) were synthesized from absorbent cotton. Two pretreatments viz. dewaxing and bleaching with mild alkali were applied to the precursor (cotton). Acid hydrolysis was conducted with H2SO4 and dissolution of cotton was achieved with a mixture of NaOH-thiourea-urea-H2O at -3°C. Synthesized cellulose samples were characterized using FTIR, XRD, SEM, BET, and zeta potential. It seems that synthesis conditions contributed to negative surface charge on cellulose samples and CNCs had the higher negative surface charge compared to CNFs. Furthermore, BET surface area, pore volume and pore diameter of CNCs were found to be higher as compared to CNFs. The dewaxed cellulose nanofibers (CNF D) had a slightly higher BET surface area (0.47m(2)/g) and bigger pore diameter (59.87Å) from attenuated contraction compared to waxed cellulose nanofibers (CNFW) (0.38m(2)/g and 44.89Å). The XRD of CNCs revealed a semi-crystalline structure and the dissolution agents influenced the crystallinity of CNFs. SEM images showed the porous nature of CNFs, the flaky nature and the nano-sized width of CNCs. Synthesized CNF D showed a better potential as an adsorbent with an average lead removal efficiency of 91.49% from aqueous solution.

  11. Synthesis and characterization of novel cellulose ether sulfates.

    Science.gov (United States)

    Rohowsky, Juta; Heise, Katja; Fischer, Steffen; Hettrich, Kay

    2016-05-20

    The synthesis and characterization of novel cellulose sulfate derivatives was reported. Various cellulose ethers were prepared in a homogeneous reaction with common sulfating agents. The received product possess different properties in dependence on the reaction conditions like sulfating agent, solvent, reaction time and reaction temperature. The cellulose ether sulfates are all soluble in water, they rheological behavior could be determined by viscosity measurements and the determination of the sulfur content by elemental analysis lead to a resulting degree of substitution ascribed to sulfate groups (DSSul) of the product. A wide range of products from DSSul 0.1 to DSSul 2.7 will be obtained. Furthermore the cellulose sulfate ethers could be characterized by Raman spectroscopy.

  12. Optimization of cellulose acrylate and grafted 4-vinylpyridine and 1-vinylimidazole synthesis

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    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 (Cell-PVP, 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

  13. Zinc impregnated cellulose nanocomposites: Synthesis, characterization and applications

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    Ali, Attarad; Ambreen, Sidra; Maqbool, Qaisar; Naz, Sania; Shams, Muhammad Fahad; Ahmad, Madiha; Phull, Abdul Rehman; Zia, Muhammad

    2016-11-01

    Nanocomposite materials have broad applicability due to synergistic effect of combined components. In present investigation, cellulose isolated from citrus peel waste is used as a supporting material; impregnation of zinc oxide nanoparticles via co-precipitation method. The characterization of nano composite is carried out through Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) analysis, scanning electron microscopy (SEM) and Thermo-gravimetric analysis (TGA) resulting less than 10 μm cellulose fiber and approx. 50 nm ZnO NPs. Zinc oxide impregnated cellulose (ZnO-Cel) exhibited significant bacterial devastation property when compared to ZnO NPs or Cellulose via disc diffusion and colony forming unit methods. In addition, the ZnO-Cel exhibited significant total antioxidant, and minor DPPH free radical scavenging and total reducing power activities. The nano composite also showed time dependent increase in photocatalytic by effectively degrading methylene blue dye up to 69.5% under sunlight irradiation within 90 min. The results suggest effective utilization of cellulose obtained from citrus waste and synthesis of pharmacologically important nano-composites that can be exploited in wound dressing; defence against microbial attack and healing due to antioxidative property, furthermore can also be used for waste water treatment.

  14. Acetobixan, an inhibitor of cellulose synthesis identified by microbial bioprospecting.

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    Xia, Ye; Lei, Lei; Brabham, Chad; Stork, Jozsef; Strickland, James; Ladak, Adam; Gu, Ying; Wallace, Ian; DeBolt, Seth

    2014-01-01

    In plants, cellulose biosynthesis is an essential process for anisotropic growth and therefore is an ideal target for inhibition. Based on the documented utility of small-molecule inhibitors to dissect complex cellular processes we identified a cellulose biosynthesis inhibitor (CBI), named acetobixan, by bio-prospecting among compounds secreted by endophytic microorganisms. Acetobixan was identified using a drug-gene interaction screen to sift through hundreds of endophytic microbial secretions for one that caused synergistic reduction in root expansion of the leaky AtcesA6prc1-1 mutant. We then mined this microbial secretion for compounds that were differentially abundant compared with Bacilli that failed to mimic CBI action to isolate a lead pharmacophore. Analogs of this lead compound were screened for CBI activity, and the most potent analog was named acetobixan. In living Arabidopsis cells visualized by confocal microscopy, acetobixan treatment caused CESA particles localized at the plasma membrane (PM) to rapidly re-localize to cytoplasmic vesicles. Acetobixan inhibited 14C-Glc uptake into crystalline cellulose. Moreover, cortical microtubule dynamics were not disrupted by acetobixan, suggesting specific activity towards cellulose synthesis. Previous CBI resistant mutants such as ixr1-2, ixr2-1 or aegeus were not cross resistant to acetobixan indicating that acetobixan targets a different aspect of cellulose biosynthesis.

  15. Acetobixan, an inhibitor of cellulose synthesis identified by microbial bioprospecting.

    Directory of Open Access Journals (Sweden)

    Ye Xia

    Full Text Available In plants, cellulose biosynthesis is an essential process for anisotropic growth and therefore is an ideal target for inhibition. Based on the documented utility of small-molecule inhibitors to dissect complex cellular processes we identified a cellulose biosynthesis inhibitor (CBI, named acetobixan, by bio-prospecting among compounds secreted by endophytic microorganisms. Acetobixan was identified using a drug-gene interaction screen to sift through hundreds of endophytic microbial secretions for one that caused synergistic reduction in root expansion of the leaky AtcesA6prc1-1 mutant. We then mined this microbial secretion for compounds that were differentially abundant compared with Bacilli that failed to mimic CBI action to isolate a lead pharmacophore. Analogs of this lead compound were screened for CBI activity, and the most potent analog was named acetobixan. In living Arabidopsis cells visualized by confocal microscopy, acetobixan treatment caused CESA particles localized at the plasma membrane (PM to rapidly re-localize to cytoplasmic vesicles. Acetobixan inhibited 14C-Glc uptake into crystalline cellulose. Moreover, cortical microtubule dynamics were not disrupted by acetobixan, suggesting specific activity towards cellulose synthesis. Previous CBI resistant mutants such as ixr1-2, ixr2-1 or aegeus were not cross resistant to acetobixan indicating that acetobixan targets a different aspect of cellulose biosynthesis.

  16. 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.

  17. Regiocontroll synthesis cellulose-graft-polycaprolactone copolymer (2,3-di-O-PCL-cellulose by a new route

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    K. L. Wang

    2017-12-01

    Full Text Available A new and convenient route to the regiocontrolled synthesis of a cellulose-based derivate copolymer (2,3-di-O-polycaprolactone-cellulose grafting ε-caprolactone (ε-CL from α-cellulose, cellulose-graft-polycaprolactone (cellulose-g-PCL, by a classical ring-opening polymerization (ROP reaction, using stannous octoate (Sn(Oct2 as catalyst, in 68% concentration of zinc chloride aqueous solution at 120 °C was presented. By controlling the hydroxyl of cellulose/ε-CL, catalyst/monomer ratio and the reaction time, the molecular architecture of the copolymers can be altered. The solubility of cellulose in zinc chloride aqueous was indicated by UV/VIS spectrometer and rheological measurements. The structures and thermal properties of cellulose-g-polycaprolactone copolymers were characterized using Fourier Transform Infrared (FT-IR, Proton Nuclear Magnetic Resonance Spectroscopy (1H NMR, X-ray Diffraction (XRD, Thermogravimetric Analysis (TGA, Differential Scanning Calorimetry (DSC and Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES. The interesting results confirm that zinc chloride solution can break the intra-molecular hydrogen bonds of cellulose selectively (not only O3H···O5, but also O2H···O6, and has no effect on the inter-molecular hydrogen bonds (O6H···O3. And the grafting reactivity of hydroxyl on cellulose is C2–OH > 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.

  18. Microwave-Assisted Hydrothermal Synthesis of Cellulose/Hydroxyapatite Nanocomposites

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    Lian-Hua Fu

    2016-09-01

    Full Text Available In this paper, we report a facile, rapid, and green strategy for the synthesis of cellulose/hydroxyapatite (HA nanocomposites using an inorganic phosphorus source (sodium dihydrogen phosphate dihydrate (NaH2PO4·2H2O, or organic phosphorus sources (adenosine 5′-triphosphate disodium salt (ATP, creatine phosphate disodium salt tetrahydrate (CP, or D-fructose 1,6-bisphosphate trisodium salt octahydrate (FBP through the microwave-assisted hydrothermal method. The effects of the phosphorus sources, heating time, and heating temperature on the phase, size, and morphology of the products were systematically investigated. The experimental results revealed that the phosphate sources played a critical role on the phase, size, and morphology of the minerals in the nanocomposites. For example, the pure HA was obtained by using NaH2PO4·2H2O as phosphorus source, while all the ATP, CP, and FBP led to the byproduct, calcite. The HA nanostructures with various morphologies (including nanorods, pseudo-cubic, pseudo-spherical, and nano-spherical particles were obtained by varying the phosphorus sources or adjusting the reaction parameters. In addition, this strategy is surfactant-free, avoiding the post-treatment procedure and cost for the surfactant removal from the product. We believe that this work can be a guidance for the green synthesis of cellulose/HA nanocomposites in the future.

  19. 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 Synthase-Interactive 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.

  20. In Vivo Curdlan/Cellulose Bionanocomposite Synthesis by Genetically Modified Gluconacetobacter xylinus.

    Science.gov (United States)

    Fang, Ju; Kawano, Shin; Tajima, Kenji; Kondo, Tetsuo

    2015-10-12

    Bacterial cellulose pellicle produced by Gluconacetobacter xylinus (G. xylinus) is one of the best biobased materials having a unique supernetwork structure with remarkable physiochemical properties for a wide range of medical and tissue-engineering applications. It is still necessary to modify them to obtain materials suitable for biomedical use with satisfactory mechanical strength, biodegradability, and bioactivity. The aim of this research was to develop a gene-transformation route for the production of bacterial cellulose/Curdlan (β-1,3-glucan) nanocomposites by separate but simultaneous in vivo synthesis of cellulose and Curdlan. Modification of the cellulose-nanofiber-producing system of G. xylinus enabled Curdlan to be synthesized simultaneously with cellulose nanofibers in vivo, resulting in biopreparation of nanocomposites. The obtained Curdlan/cellulose composites were characterized, and their properties were compared with those of normal bacterial cellulose pellicles, indicating that Curdlan mixed with the cellulose nanofibers at the nanoscale without disruption of the nanofiber network structure in the pellicle.

  1. Green Synthesis of Hydroxyethyl Cellulose-Stabilized Silver Nanoparticles

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    M. A. El-Sheikh

    2013-01-01

    Full Text Available Green synthesis aims to minimize the use of unsafe reactants and maximize the efficiency of synthesis process. These could be achieved by using environmentally compassionate polymers and nontoxic chemicals. Hydroxyethyl cellulose (HEC, an ecofriendly polymer, was used as both reducing and stabilizing agents in the synthesis of stable silver nanoparticles, while silver nitrate was used as a precursor and water as a solvent. The formation of silver nanoparticles was assessed by monitoring UV-vis spectra of the silver colloidal solution. The size of the nanoparticles was measured using transmission electron microscope (TEM. Reaction kinetics was followed by measuring the absorbance of silver colloidal solution at different time intervals. Optimum reaction conditions revealed that the highest absorbance was obtained using HEC : AgNO3 of 1.5 : 0.17 (g/100 cm3 at 70°C for 120 min at pH 12. The Ag0 nanoparticles colloidal solution so obtained (1000 ppm were found stable in aqueous solution over a period of six months at room temperature (°C. The sizes of these nanoparticles were found in the range of 11–60 nm after six months of storing. FTIR spectra confirmed the interaction of both the aldehyde and OH groups in the synthesis and stabilization of silver nanoparticles.

  2. Effect of late planting and shading on cellulose synthesis during cotton fiber secondary wall development.

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    Ji Chen

    Full Text Available Cotton-rapeseed or cotton-wheat double cropping systems are popular in the Yangtze River Valley and Yellow River Valley of China. Due to the competition of temperature and light resources during the growing season of double cropping system, cotton is generally late-germinating and late-maturing and has to suffer from the coupling of declining temperature and low light especially in the late growth stage. In this study, late planting (LP and shading were used to fit the coupling stress, and the coupling effect on fiber cellulose synthesis was investigated. Two cotton (Gossypium hirsutum L. cultivars were grown in the field in 2010 and 2011 at three planting dates (25 April, 25 May and 10 June each with three shading levels (normal light, declined 20% and 40% PAR. Mean daily minimum temperature was the primary environmental factor affected by LP. The coupling of LP and shading (decreased cellulose content by 7.8%-25.5% produced more severe impacts on cellulose synthesis than either stress alone, and the effect of LP (decreased cellulose content by 6.7%-20.9% was greater than shading (decreased cellulose content by 0.7%-5.6%. The coupling of LP and shading hindered the flux from sucrose to cellulose by affecting the activities of related cellulose synthesis enzymes. Fiber cellulose synthase genes expression were delayed under not only LP but shading, and the coupling of LP and shading markedly postponed and even restrained its expression. The decline of sucrose-phosphate synthase activity and its peak delay may cause cellulose synthesis being more sensitive to the coupling stress during the later stage of fiber secondary wall development (38-45 days post-anthesis. The sensitive difference of cellulose synthesis between two cultivars in response to the coupling of LP and shading may be mainly determined by the sensitiveness of invertase, sucrose-phosphate synthase and cellulose synthase.

  3. The Synthesis of a Novel Cellulose Physical Gel

    OpenAIRE

    Jiufang Duan; Xiaojian Zhang; Jianxin Jiang; Chunrui Han; Jun Yang; Liujun Liu; Hongyun Lan; Daozhan Huang

    2014-01-01

    Cellulose possessing β-cyclodextrin (β-CD) was used as a host molecule and cellulose possessing ferrocene (Fc) as a guest polymer. Infrared spectra, differential scanning calorimetry (DSC), ultraviolet spectroscopy (UV), and contact angle analysis were used to characterise the material structure and the inclusion behaviour. The results showed that the β-CD-cellulose and the Fc-cellulose can form inclusion complexes. Moreover, ferrocene oxidation, and reduction of state can be adjusted by sodi...

  4. Variation in oxygen isotope fractionation during cellulose synthesis: intramolecular and biosynthetic effects.

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    Sternberg, Leonel; Pinzon, Maria Camila; Anderson, William T; Jahren, A Hope

    2006-10-01

    The oxygen isotopic composition of plant cellulose is commonly used for the interpretations of climate, ecophysiology and dendrochronology in both modern and palaeoenvironments. Further applications of this analytical tool depends on our in-depth knowledge of the isotopic fractionations associated with the biochemical pathways leading to cellulose. Here, we test two important assumptions regarding isotopic effects resulting from the location of oxygen in the carbohydrate moiety and the biosynthetic pathway towards cellulose synthesis. We show that the oxygen isotopic fractionation of the oxygen attached to carbon 2 of the glucose moieties differs from the average fractionation of the oxygens attached to carbons 3-6 from cellulose by at least 9%, for cellulose synthesized within seedlings of two different species (Triticum aestivum L. and Ricinus communis L.). The fractionation for a given oxygen in cellulose synthesized by the Triticum seedlings, which have starch as their primary carbon source, is different than the corresponding fractionation in Ricinus seedlings, within which lipids are the primary carbon source. This observation shows that the biosynthetic pathway towards cellulose affects oxygen isotope partitioning, a fact heretofore undemonstrated. Our findings may explain the species-dependent variability in the overall oxygen isotope fractionation during cellulose synthesis, and may provide much-needed insight for palaeoclimate reconstruction using fossil cellulose.

  5. The Synthesis of a Novel Cellulose Physical Gel

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    Jiufang Duan

    2014-01-01

    Full Text Available Cellulose possessing β-cyclodextrin (β-CD was used as a host molecule and cellulose possessing ferrocene (Fc as a guest polymer. Infrared spectra, differential scanning calorimetry (DSC, ultraviolet spectroscopy (UV, and contact angle analysis were used to characterise the material structure and the inclusion behaviour. The results showed that the β-CD-cellulose and the Fc-cellulose can form inclusion complexes. Moreover, ferrocene oxidation, and reduction of state can be adjusted by sodium hypochlorite (NaClO as an oxidant and glutathione (GSH as a reductant. In this study, a physical gel based on β-CD-cellulose/Fc-cellulose was formed under mild conditions in which autonomous healing between cut surfaces occurred after 24 hours. The physical gel can be controlled in the sol-gel transition. The compressive strength of the Fc-cellulose/β-CD-cellulose gel increased with increased cellulose concentration. The host-guest interaction between the side chains of cellulose could strengthen the gel. The cellulose physical gel may eventually be used as a stimulus-responsive, healing material in biomedical applications.

  6. Synthesis and Characterization of a Novel Cellulose Nonionic Ether

    Institute of Scientific and Technical Information of China (English)

    SHAO Zi-qiang; XU Kun; TIAN Yong-sheng; WANG Fei-jun; WANG Ji-xun

    2005-01-01

    A kind of novel cellulose ether-trihydroxybutyl cellulose (THBC) was synthesized. The process includes the steam explosion treatment of cotton cellulose, alkalization, etherification and purification. Sweep electron microscope (SEM), Fourier transform infrared (FTIR) and X-ray diffraction were used to characterize the cellulose pretreated and the product. The effects of reaction conditions (temperature, time) on the molecular substitution (Sm) were discussed. To obtain a higher degree of molecular substitution, the reaction temperature is 80 ℃, and the reaction time is 4 h.

  7. Synthesis of cellulose dehydroabietate in ionic liquid [bmim]Br.

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    Xu, Xuetang; Duan, Wengui; Huang, Mei; Li, Guanghua

    2011-09-27

    A new type of cellulose derivative, cellulose dehydroabietate (CDA), was synthesized by the O-acylation reaction of cellulose with dehydroabietic acid chloride (DHAC) using ionic liquid 1-butyl-3-methylimidazolium bromide ([bmim]Br) as a solvent and 4-dimethyl-aminopyridine (DMAP) as a catalyst. The resulting CDA was characterized by means of FT-IR, X-ray diffraction (XRD), scanning electron microscopy (SEM), thermal gravimetric analysis (TGA), and elemental analysis. Also, some properties of CDA were determined. These results showed that CDA has better solubility, water-repellency, and resistance to acids and bases than raw cellulose, and these properties increase with the DS of CDA.

  8. Binding Cellulose and Chitosan via Intermolecular Inclusion Interaction: Synthesis and Characterisation of Gel

    Directory of Open Access Journals (Sweden)

    Jiufang Duan

    2015-01-01

    Full Text Available A novel cellulose-chitosan gel was successfully prepared in three steps: (1 ferrocene- (Fc- cellulose with degrees of substitution (DS of 0.5 wt% was synthesised by ferrocenecarboxylic acid and cellulose within dimethylacetamide/lithium chloride (DMAc/LiCl; (2 the β-cyclodextrin (β-CD groups were introduced onto the chitosan chains by reacting chitosan with epichlorohydrin in dimethyl sulphoxide and a DS of 0.35 wt%; (3 thus, the cellulose-chitosan gel was obtained via an intermolecular inclusion interaction of Fc-cellulose and β-CD-chitosan in DMA/LiCl, that is, by an intermolecular inclusion interaction, between the Fc groups of cellulose and the β-CD groups on the chitosan backbone at room temperature. The successful synthesis of Fc-cellulose and β-CD-chitosan was characterised by 13C-NMR spectroscopy. The gel based on β-CD-chitosan and Fc-cellulose was formed under mild conditions which can engender autonomous healing between cut surfaces after 24 hours: the gel cannot self-heal while the cut surfaces were coated with a solution of a competitive guest (adamantane acid. The cellulose-chitosan complex made by this method underwent self-healing. Therefore, this study provided a novel method of expanding the application of chitosan by binding it with another polymer.

  9. A molecular genetic approach to understanding eukaryotic cellulose synthesis. Final technical report, March 15, 1995--March 14, 1997

    Energy Technology Data Exchange (ETDEWEB)

    Blanton, R.L.

    1997-11-01

    In an attempt to understand eukaryotic cellulose synthesis, this research investigates the cellulose biosynthetic pathway of Dictyostelium discoideum. Attention is focused on the following: use of a newly developed method of tagged insertional mutagenesis to generate mutants in cellulose biosynthesis; and exploiting the monolayer culture system to identify differences in mRNA populations between DIF-induced (and cellulose-synthesizing) versus non-induced cells.

  10. Synthesis and Self-Assembly of Cellulose Microfibrils from Reconstituted Cellulose Synthase.

    Science.gov (United States)

    Cho, Sung Hyun; Purushotham, Pallinti; Fang, Chao; Maranas, Cassandra; Díaz-Moreno, Sara M; Bulone, Vincent; Zimmer, Jochen; Kumar, Manish; Nixon, B Tracy

    2017-09-01

    Cellulose, the major component of plant cell walls, can be converted to bioethanol and is thus highly studied. In plants, cellulose is produced by cellulose synthase, a processive family-2 glycosyltransferase. In plant cell walls, individual β-1,4-glucan chains polymerized by CesA are assembled into microfibrils that are frequently bundled into macrofibrils. An in vitro system in which cellulose is synthesized and assembled into fibrils would facilitate detailed study of this process. Here, we report the heterologous expression and partial purification of His-tagged CesA5 from Physcomitrella patens Immunoblot analysis and mass spectrometry confirmed enrichment of PpCesA5. The recombinant protein was functional when reconstituted into liposomes made from yeast total lipid extract. The functional studies included incorporation of radiolabeled Glc, linkage analysis, and imaging of cellulose microfibril formation using transmission electron microscopy. Several microfibrils were observed either inside or on the outer surface of proteoliposomes, and strikingly, several thinner fibrils formed ordered bundles that either covered the surfaces of proteoliposomes or were spawned from liposome surfaces. We also report this arrangement of fibrils made by proteoliposomes bearing CesA8 from hybrid aspen. These observations describe minimal systems of membrane-reconstituted CesAs that polymerize β-1,4-glucan chains that coalesce to form microfibrils and higher-ordered macrofibrils. How these micro- and macrofibrils relate to those found in primary and secondary plant cell walls is uncertain, but their presence enables further study of the mechanisms that govern the formation and assembly of fibrillar cellulosic structures and cell wall composites during or after the polymerization process controlled by CesA proteins. © 2017 American Society of Plant Biologists. All Rights Reserved.

  11. Synthesis and properties of fluorescent cotton cellulose labeled with norfloxacin

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    To expand the application of cellulose in the field of fluorescence techniques, the cotton cellulose was labeled with norfloxacin (Cell-NF) via a three-step reaction, involving alkali treatment, epoxy activation, and opening of the epoxy rings with norfloxacin molecules. And the coordination complexes of Cell-NF with rare earth ions terbium (Cell-NF-Tb) and europium (Cell-NF-Eu) were obtained. The products were detected by IR, TG, XPS, UV and fluorescence spectra. Results showed that the norfloxacin content of the labeled cellulose was about 6.73 w‰ and the start temperature of decomposition of the Cell-NF was raised by 40°C compared with the stock cotton cellulose. When excited at 340 nm, the Cell-NF, Cell-NF-Tb, and Cell-NF-Eu in the solid state could emit violet (430 nm), green (549 nm) and red (620 nm) light, respectively.

  12. 6-Deoxy-6-aminoethyleneamino cellulose: synthesis and study of hemocompatibility.

    Science.gov (United States)

    Zieger, Michael; Wurlitzer, Michael; Wiegand, Cornelia; Reddersen, Kirsten; Finger, Susanne; Elsner, Peter; Laudeley, Peggy; Liebert, Tim; Heinze, Thomas; Hipler, Uta-Christina

    2015-01-01

    Hemocompatibility of aqueous solutions of antimicrobial 6-deoxy-6-aminoethyleneamino (AEA) cellulose with different degrees of substitution (DS, 0.54-0.92) was investigated in vitro. The AEA cellulose derivatives were synthesized by tosylation of cellulose and subsequent nucleophilic substitution with 1,2-diaminoethane. The structure was confirmed by elemental analysis as well as by FTIR and NMR spectroscopies. Markers for coagulation (thrombin generation, aPTT, PT, blood clotting, thrombocyte activation) and membrane integrity (hemolysis) were measured in human whole blood, human platelet-rich plasma, human pooled plasma, and erythrocytes suspension. AEA cellulose with a low DS of 0.54 showed the highest hemocompatibility in vitro, suggesting the possibility of biomedical applications.

  13. Cellulose acetate fibers prepared from different raw materials with rapid synthesis method.

    Science.gov (United States)

    Chen, Jinghuan; Xu, Jikun; Wang, Kun; Cao, Xuefei; Sun, Runcang

    2016-02-10

    Transesterification is a mild process to prepare cellulose acetate (CA) as compared with the traditional method. In this study, CA fibers were produced from six cellulose raw materials based on a simple and rapid transesterification method. The properties of the CA solutions and the obtained CA fibers were investigated in detail. Results showed that all of the cellulose raw materials were esterified within 15 min, and spinning dopes could be obtained by concentrating the CA solutions via vacuum distillation. The XRD, FT-IR, (1)H, (13)C and HSQC NMR analysis confirmed the successful synthesis of CA. The degree of substitution (DS) of the obtained CA was significantly affected by the degree of polymerization (DP) of cellulose raw materials, which further influenced the viscosity of CA solutions as well as the structural, thermal and mechanical properties of the CA fibers.

  14. Electroless synthesis of cellulose-metal aerogel composites

    Science.gov (United States)

    Schestakow, M.; Muench, F.; Reimuth, C.; Ratke, L.; Ensinger, W.

    2016-05-01

    An environmentally benign electroless plating procedure enables a dense coating of silver nanoparticles onto complex cellulose aerogel structures. In the course of the nanoparticle deposition, the morphological characteristics of the aerogel are preserved, such as the continuous self-supporting network structure. While achieving a high metal loading, the large specific surface area as well as the low density is retained in the cellulose-metal aerogel composite. Due to the interesting features of cellulose aerogel substrates (e.g., the accessibility of its open-porous network) and electroless plating (e.g., the possibility to control the density, size, and composition of the deposited metal nanoparticles), the outlined synthetic scheme provides a facile and flexible route towards advanced materials in heterogeneous catalysis, plasmonics, and sensing.

  15. Synthesis of cellulose methylcarbonate in ionic liquids using dimethylcarbonate.

    Science.gov (United States)

    Labafzadeh, Sara R; Helminen, K Juhani; Kilpeläinen, Ilkka; King, Alistair W T

    2015-01-01

    Dialkylcarbonates are viewed as low-cost, low-toxicity reagents, finding application in many areas of green chemistry. Homogeneous alkoxycarbonylation of cellulose was accomplished by applying dialkycarbonates (dimethyl and diethyl carbonate) in the ionic liquid-electrolyte trioctylphosphonium acetate ([P8881 ][OAc])/DMSO or 1-ethyl-3-methylimidazolium acetate ([emim][OAc]). Cellulose dialkylcarbonates with a moderate degree of substitution (DS∼1) are accessible via this procedure and cellulose methylcarbonate was thoroughly characterized for its chemical and physical properties after regeneration. This included HSQC & HMBC NMR, ATR-IR, molecular weight distribution, morphology, thermal properties, and barrier properties after film formation. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Interactions between membrane-bound cellulose synthases involved in the synthesis of the secondary cell wall

    NARCIS (Netherlands)

    Timmers, J.F.P.; Vernhettes, S.; Desprez, T.; Vincken, J.P.; Visser, R.G.F.; Trindade, L.M.

    2009-01-01

    It has not yet been reported how the secondary CESA (cellulose synthase) proteins are organized in the rosette structure. A membrane-based yeast two-hybrid (MbYTH) approach was used to analyze the interactions between the CESA proteins involved in secondary cell wall synthesis of Arabidopsis and the

  17. Environmentally friendly microwave ionic liquids synthesis of hybrids from cellulose and AgX (X=Cl, Br).

    Science.gov (United States)

    Dong, Yan-Yan; He, Jing; Sun, Shao-Long; Ma, Ming-Guo; Fu, Lian-Hua; Sun, Run-Cang

    2013-10-15

    The purpose of this article was to explore an environmentally friendly strategy to synthesis of biomass-based hybrids. Herein, microwave-assisted ionic liquids method was applied to fabricate the hybrids from cellulose and AgX (X=Cl, Br) using cellulose and AgNO3. The ionic liquids act simultaneously as a solvent, a microwave absorber, and a reactant. Ionic liquids provided Cl(-) or Br(-) to the synthesis of AgCl or AgBr crystals; thus no additional reactant is needed. The products are characterized by X-ray powder diffraction (XRD), Fourier transform infrared spectrometry (FTIR), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), and differential thermal analysis (DTA). The cellulose-Ag/AgCl hybrid and cellulose-Ag/AgBr hybrid were also obtained by using cellulose-AgCl and cellulose-AgBr hybrids as precursors. This environmentally friendly microwave-assisted ionic liquids method is beneficial to the hybrids with high dispersion.

  18. Synthesis of cellulose nanofiber composites for mechanical reinforcement and other advanced applications

    Science.gov (United States)

    Xu, Xuezhu

    Cellulose nanofibers from bioresources have attracted intensive research interest in recent years due to their unique combination of properties including high strength and modulus, low density, biocompatibility/biodegradability and rich surface chemistry for functionalization. The nanofibers have been widely studied as nanoreinforcements in polymer nanocomposites; while the nanocomposite research is still very active, new research directions of using the nanofibers for hydrogels/aerogels, template for nanoparticle synthesis, scaffold, carbon materials, nanopaper, etc. have emerged. In this Ph.D. thesis, fundamental studies and application developments are performed on three types of cellulose nanofibers, i.e. cellulose nanocrystals (CNCs), cellulose nanofibrils (CNFs) and bacterial cellulose (BC). First CNCs and CNFs are systematically compared in terms of their effects on the mechanical properties, crystallization and failure behavior of the nanocomposites, which provides a guideline for the design of cellulose nanofiber reinforced composites. Second, CNFs and BC are used to develop core-shell carbon fibers and flexible carbon aerogels for energy storage applications. This part is focused on developing nanocarbon materials with multi-scale features. Lastly, hybrid CNC/CNF nanopaper with superior optical, mechanical, and electrical properties is developed and its application is demonstrated on a LED device.

  19. Plasma-enhanced synthesis of green flame retardant cellulosic materials

    Science.gov (United States)

    Totolin, Vladimir

    The natural fiber-containing fabrics and composites are more environmentally friendly, and are used in transportation (automobiles, aerospace), military applications, construction industries (ceiling paneling, partition boards), consumer products, etc. Therefore, the flammability characteristics of the composites based on polymers and natural fibers play an important role. This dissertation presents the development of plasma assisted - green flame retardant coatings for cellulosic substrates. The overall objective of this work was to generate durable flame retardant treatment on cellulosic materials. In the first approach sodium silicate layers were pre-deposited onto clean cotton substrates and cross linked using low pressure, non-equilibrium oxygen plasma. A statistical design of experiments was used to optimize the plasma parameters. The modified cotton samples were tested for flammability using an automatic 45° angle flammability test chamber. Aging tests were conducted to evaluate the coating resistance during the accelerated laundry technique. The samples revealed a high flame retardant behavior and good thermal stability proved by thermo-gravimetric analysis. In the second approach flame retardant cellulosic materials have been produced using a silicon dioxide (SiO2) network coating. SiO 2 network armor was prepared through hydrolysis and condensation of the precursor tetraethyl orthosilicate (TEOS), prior coating the substrates, and was cross linked on the surface of the substrates using atmospheric pressure plasma (APP) technique. Due to protection effects of the SiO2 network armor, the cellulosic based fibers exhibit enhanced thermal properties and improved flame retardancy. In the third approach, the TEOS/APP treatments were extended to linen fabrics. The thermal analysis showed a higher char content and a strong endothermic process of the treated samples compared with control ones, indicating a good thermal stability. Also, the surface analysis proved

  20. Synthesis, antibacterial and thermal studies of cellulose nanocrystal stabilized ZnO-Ag heterostructure nanoparticles.

    Science.gov (United States)

    Azizi, Susan; Ahmad, Mansor Bin Hj; Hussein, Mohd Zobir; Ibrahim, Nor Azowa

    2013-05-28

    Synthesis of ZnO-Ag heterostructure nanoparticles was carried out by a precipitation method with cellulose nanocrystals (CNCs) as a stabilizer for antimicrobial and thermal studies. ZnO-Ag nanoparticles were obtained from various weight percentages of added AgNO₃ relative to Zn precursors for evaluating the best composition with enhanced functional properties. The ZnO-Ag/CNCs samples were characterized systematically by TEM, XRD, UV, TGA and DTG. From the TEM studies we observed that ZnO-Ag heterostructure nanoparticles have spherical shapes with size diameters in a 9-35 nm range. The antibacterial activities of samples were assessed against the bacterial species Salmonella choleraesuis and Staphylococcus aureus. The CNC-stabilized ZnO-Ag exhibited greater bactericidal activity compared to cellulose-free ZnO-Ag heterostructure nanoparticles of the same particle size. The incorporation of ZnO-Ag hetreostructure nanoparticles significantly increased the thermal stability of cellulose nanocrystals.

  1. Synthesis and characterization of graphene/cellulose nanocomposite

    Science.gov (United States)

    Kafy, Abdullahil; Yadav, Mithilesh; Kumar, Kishor; Kumar, Kishore; Mun, Seongcheol; Gao, Xiaoyuan; Kim, Jaehwan

    2014-04-01

    Cellulose is one of attractive natural polysaccharides in nature due to its good chemical stability, mechanical strength, biocompatibility, hydrophilic, and biodegradation properties [1-2]. The main disadvantages of biopolymer films like cellulose are their poor mechanical properties. Modification of polymers with inorganic materials is a new way to improve polymer properties such as mechanical strength [3-4]. Presently, the use of graphene/graphene oxide (GO) in materials research has attracted tremendous attention in the past 40 years in various fields including biomedicine, information technology and nanotechnology[5-7]. Graphene, a single sheet of graphite, has an ideal 2D structure with a monolayer of carbon atoms packed into a honeycomb crystal plane. Using both experimental and theoretical scientific research, researchers including Geim, Rao and Stankovich [8-10] have described the attractiveness of graphene in the materials research field. Due to its sp2 hybrid carbon network as well as extraordinary mechanical, electronic, and thermal properties, graphene has opened new pathways for developing a wide range of novel functional materials. Perfect graphene does not exist naturally, but bulk and solution processable functionalized graphene materials including graphene oxide (GO) can now be prepared [11-13].The large surface area of GO has a number of functional groups, such as -OH, -COOH, -O- , and C=O, which make GO hydrophilic and readily dispersible in water as well as some organic solvents[14] , thereby providing a convenient access to fabrication of graphene-based materials by solution casting. According to several reports [15-17], GO can be dispersed throughout a selected polymer matrix to make GO-based nanocomposites with excellent mechanical and thermal properties. Since GO is prepared from low-cost graphite, it has an outstanding price advantage over CNTs, which has encouraged studies of GO/synthetic polymer composites [18-20]. In some reported papers

  2. Synthesis of Alkaline-Soluble Cellulose Methyl Carbamate Using a Reactive Deep Eutectic Solvent.

    Science.gov (United States)

    Sirviö, Juho Antti; Heiskanen, Juha P

    2017-01-20

    This study presents the use of a reactive deep eutectic solvent (DES) for the chemical modification of wood cellulose fibers. DES based on dimethylurea and ZnCl2 was used to synthetize cellulose methyl carbamate (CMeC). This synthesis was performed at elevated temperature under solvent-free conditions. Chemical characterization based on FTIR and NMR indicated that methyl carbamate was successfully introduced to cellulose, and a degree of substitution (DS) of 0.17 was obtained after 3 h of reaction at 150 °C. The product with a DS of 0.17 exhibited good alkaline solubility (in 3 % NaOH solution) after freeze-thawing, whereas the original cellulose fibers were practically insoluble even in 9 % NaOH. As dimethylurea can be produced from CO2 , this method can be used as a sustainable way to obtain novel cellulose materials with desirable properties for use in a wide range of applications. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Novel route of synthesis for cellulose fiber-based hybrid polyurethane

    Science.gov (United States)

    Ikhwan, F. H.; Ilmiati, S.; Kurnia Adi, H.; Arumsari, R.; Chalid, M.

    2017-07-01

    Polyurethanes, obtained by the reaction of a diisocyanate compound with bifunctional or multifunctional reagent such as diols or polyols, have been studied intensively and well developed. The wide range modifier such as chemical structures and molecular weight to build polyurethanes led to designs of materials that may easily meet the functional product demand and to the extraordinary spreading of these materials in market. Properties of the obtained polymer are related to the chemical structure of polyurethane backbone. A number polyurethanes prepared from biomass-based monomers have been reported. Cellulose fiber, as a biomass material is containing abundant hydroxyl, promising material as chain extender for building hybrid polyurethanes. In previous researches, cellulose fiber was used as filler in synthesis of polyurethane composites. This paper reported a novel route of hybrid polyurethane synthesis, which a cellulose fiber was used as chain extender. The experiment performed by reacting 4,4’-Methylenebis (cyclohexyl isocyanate) (HMDI) and polyethylene glycol with variation of molecular weight to obtained pre-polyurethane, continued by adding micro fiber cellulose (MFC) with variation of type and composition in the mixture. The experiment was evaluated by NMR, FTIR, SEM and STA measurement. NMR and FTIR confirmed the reaction of the hybrid polyurethane. STA showed hybrid polyurethane has good thermal stability. SEM showed good distribution and dispersion of sorghum-based MFC.

  4. Synthesis, isolation and characterization of methyl levulinate from cellulose catalyzed by extremely low concentration acid

    Institute of Scientific and Technical Information of China (English)

    Hui; Li; Lincai; Peng; Lu; Lin; Keli; Chen; Heng; Zhang

    2013-01-01

    A direct synthesis of methyl levulinate from cellulose alcoholysis in methanol medium under mild condition(180 210 C)catalyzed by extremely low concentration sulfuric acid(0.01 mol/L)and the product isolation were developed in this study.Effects of different process variables towards the catalytic performance were performed as a function of reaction time.The results indicated that sulfuric acid concentration,temperature and initial cellulose concentration had significant effects on the synthesis of methyl levulinate.An optimized yield of around 50%was achieved at 210 C for 120 min with sulfuric acid concentration of 0.01 mol/L and initial cellulose concentration below 100 g/L.The resulting product mixture was isolated by a distillation technique that combines an atmospheric distillation with a vacuum distillation where n-dodecane was added to help distill the heavy fraction.The light fraction including mainly methanol could be reused as the reaction medium without any substantial change in the yield of methyl levulinate.The chemical composition and structural of lower heavy fraction were characterized by GC/MS,FTIR,1H-NMR and13C-NMR techniques.Methyl levulinate was found to be a major ingredient of lower heavy fraction with the content over 96%.This pathway is efficient,environmentally benign and economical for the production of pure levulinate esters from cellulose.

  5. Synthesis of cellulose by Acetobacter xylinum. VI. Growth on citric acid-cycle intermediates.

    Science.gov (United States)

    GROMET-ELHANAN, Z; HESTRIN, S

    1963-02-01

    Gromet-Elhanan, Zippora (The Hebrew University, Jerusalem, Israel) and Shlomo Hestrin. Synthesis of cellulose by Acetobacter xylinum. VI. Growth on citric acid-cycle intermediates. J. Bacteriol. 85:284-292. 1963.-Acetobacter xylinum could be made to grow on ethanol, acetate, succinate, or l-malate. The growth was accompanied by formation of opaque leathery pellicles on the surface of the growth medium. These pellicles were identified as cellulose on the basis of their chemical properties, solubility behavior, and infrared absorption spectra. Washed-cell suspensions prepared from cultures grown on ethanol or the organic acids, in contrast to washed sugar-grown cells, were able to transform citric-cycle intermediates into cellulose. The variations in the substrate spectrum of cellulose synthesis between sugar-grown cells and organic acids-grown cells were found to be correlated with differences in the oxidative capacity of the cells. The significance of the findings that A. xylinum could be made to grow on ethanol on complex as well as synthetic media is discussed from the viewpoint of the whole pattern of Acetobacter classification.

  6. Synthesis and urease enzyme inhibitory effects of some dicoumarols.

    Science.gov (United States)

    Khan, Khalid M; Iqbal, Sajid; Lodhi, Muhammad A; Maharvi, Ghulam M; Perveen, Shahnaz; Choudhary, M I; Atta-Ur-Rahman; Chohan, Zahid H; Supuran, Claudiu T

    2004-08-01

    Dicoumarols 1-10 with substituted phenyl residues at C-11 were synthesized and screened for their urease inhibition effects. All synthesized compounds showed varying degree of urease inhibitory activity ranging from IC50 = 74.30-91.35 microM.

  7. Additional nitrogen fertilization at heading time of rice down-regulates cellulose synthesis in seed endosperm.

    Science.gov (United States)

    Midorikawa, Keiko; Kuroda, Masaharu; Terauchi, Kaede; Hoshi, Masako; Ikenaga, Sachiko; Ishimaru, Yoshiro; Abe, Keiko; Asakura, Tomiko

    2014-01-01

    The balance between carbon and nitrogen is a key determinant of seed storage components, and thus, is of great importance to rice and other seed-based food crops. To clarify the influence of the rhizosphere carbon/nitrogen balance during the maturation stage of several seed components, transcriptome analysis was performed on the seeds from rice plants that were provided additional nitrogen fertilization at heading time. As a result, it was assessed that genes associated with molecular processes such as photosynthesis, trehalose metabolism, carbon fixation, amino acid metabolism, and cell wall metabolism were differentially expressed. Moreover, cellulose and sucrose synthases, which are involved in cellulose synthesis, were down-regulated. Therefore, we compared cellulose content of mature seeds that were treated with additional nitrogen fertilization with those from control plants using calcofluor staining. In these experiments, cellulose content in endosperm from plants receiving additional nitrogen fertilization was less than that in control endosperm. Other starch synthesis-related genes such as starch synthase 1, starch phosphorylase 2, and branching enzyme 3 were also down-regulated, whereas some α-amylase and β-amylase genes were up-regulated. On the other hand, mRNA expression of amino acid biosynthesis-related molecules was up-regulated. Moreover, additional nitrogen fertilization caused accumulation of storage proteins and up-regulated Cys-poor prolamin mRNA expression. These data suggest that additional nitrogen fertilization at heading time changes the expression of some storage substance-related genes and reduces cellulose levels in endosperm.

  8. Spatio-temporal analysis of cellulose synthesis during cell plate formation in Arabidopsis.

    Science.gov (United States)

    Miart, Fabien; Desprez, Thierry; Biot, Eric; Morin, Halima; Belcram, Katia; Höfte, Herman; Gonneau, Martine; Vernhettes, Samantha

    2014-01-01

    During cytokinesis a new crosswall is rapidly laid down. This process involves the formation at the cell equator of a tubulo-vesicular membrane network (TVN). This TVN evolves into a tubular network (TN) and a planar fenestrated sheet, which extends at its periphery before fusing to the mother cell wall. The role of cell wall polymers in cell plate assembly is poorly understood. We used specific stains and GFP-labelled cellulose synthases (CESAs) to show that cellulose, as well as three distinct CESAs, accumulated in the cell plate already at the TVN stage. This early presence suggests that cellulose is extruded into the tubular membrane structures of the TVN. Co-localisation studies using GFP-CESAs suggest the delivery of cellulose synthase complexes (CSCs) to the cell plate via phragmoplast-associated vesicles. In the more mature TN part of the cell plate, we observed delivery of GFP-CESA from doughnut-shaped organelles, presumably Golgi bodies. During the conversion of the TN into a planar fenestrated sheet, the GFP-CESA density diminished, whereas GFP-CESA levels remained high in the TVN zone at the periphery of the expanding cell plate. We observed retrieval of GFP-CESA in clathrin-containing structures from the central zone of the cell plate and from the plasma membrane of the mother cell, which may contribute to the recycling of CESAs to the peripheral growth zone of the cell plate. These observations, together with mutant phenotypes of cellulose-deficient mutants and pharmacological experiments, suggest a key role for cellulose synthesis already at early stages of cell plate assembly.

  9. Posidonia oceanica as a Renewable Lignocellulosic Biomass for the Synthesis of Cellulose Acetate and Glycidyl Methacrylate Grafted Cellulose

    Directory of Open Access Journals (Sweden)

    Elena Vismara

    2013-05-01

    Full Text Available High-grade cellulose (97% α-cellulose content of 48% crystallinity index was extracted from the renewable marine biomass waste Posidonia oceanica using H2O2 and organic peracids following an environmentally friendly and chlorine-free process. This cellulose appeared as a new high-grade cellulose of waste origin quite similar to the high-grade cellulose extracted from more noble starting materials like wood and cotton linters. The benefits of α-cellulose recovery from P. oceanica were enhanced by its transformation into cellulose acetate CA and cellulose derivative GMA-C. Fully acetylated CA was prepared by conventional acetylation method and easily transformed into a transparent film. GMA-C with a molar substitution (MS of 0.72 was produced by quenching Fenton’s reagent (H2O2/FeSO4 generated cellulose radicals with GMA. GMA grafting endowed high-grade cellulose from Posidonia with adsorption capability. GMA-C removes β-naphthol from water with an efficiency of 47%, as measured by UV-Vis spectroscopy. After hydrolysis of the glycidyl group to glycerol group, the modified GMA-C was able to remove p-nitrophenol from water with an efficiency of 92%, as measured by UV-Vis spectroscopy. α-cellulose and GMA-Cs from Posidonia waste can be considered as new materials of potential industrial and environmental interest.

  10. Synthesis, topoisomerase I inhibitory and cytotoxic activities of chromone derivatives.

    Science.gov (United States)

    Maicheen, Chirattikan; Jittikoon, Jiraphun; Vajragupta, Opa; Ungwitayatorn, Jiraporn

    2013-05-01

    A series of chromone derivatives were designed as potential topoisomerase I (Top I) inhibitors based on the docking simulation study. Sixteen synthesized compounds were evaluated for Top I inhibitory activity and some compounds were further tested for in vitro cytotoxic activity. The most potent inhibitor, chromone 11b showed greater inhibitory activity (IC50 = 1.46 μM) than the known Top I inhibitors, i.e., camptothecin, fisetin and morin, but inactive against breast cancer cell (MCF-7), oral cavity cancer cell (KB) and small cell lung cancer (NCI-H187). Chromone 11c, another potent inhibitor (IC50 = 6.16 μM), exhibited cytotoxic activity against KB (IC50 = 73.32 μM) and NCI-H187 (IC50 = 36.79 μM).

  11. Interactions among three distinct CesA proteins essential for cellulose synthesis.

    Science.gov (United States)

    Taylor, Neil G; Howells, Rhian M; Huttly, Alison K; Vickers, Kate; Turner, Simon R

    2003-02-04

    In a screen to identify novel cellulose deficient mutants, three lines were shown to be allelic and define a novel complementation group, irregular xylem5 (irx5). IRX5 was cloned and encodes a member of the CesA family of cellulose synthase catalytic subunits (AtCesA4). irx5 plants have an identical phenotype to previously described mutations in two other members of this gene family (IRX1 and IRX3). IRX5, IRX3, and IRX1 are coexpressed in exactly the same cells, and all three proteins interact in detergent solubilized extracts, suggesting that three members of this gene family are required for cellulose synthesis in secondary cell walls. The association of IRX1 and IRX3 was reduced to undetectable levels in the absence of IRX5. Consequently, these data suggest that IRX5, IRX3, and IRX1 are all essential components of the cellulose synthesizing complex and the presence of all three subunits is required for the correct assembly of this complex.

  12. Synthesis and Properties of Cellulose-Functionalized POSS-SiO2/TiO2 Hybrid Composites.

    Science.gov (United States)

    Hong, Gwang-Wook; Ramesh, Sivalingam; Kim, Joo-Hyung; Kim, Hyeon-Ju; Lee, Ho-Saeng

    2015-10-01

    The mechanical, thermal, optical, electrical and morphological properties of cellulose, an excellent natural biomaterial, can be improved by organic-inorganic hybrid composite methods. Based on the pristine properties of cellulose, the preparation of cellulose-metal oxide hybrid nanocomposites using a dispersion process of nanoparticles into the cellulose host matrix by traditional methods, has limitations. Recently, the functionalized cellulose-polymer-based materials were considered to be an important class of high-performance materials, providing the synthesis of various functional hybrid nanocomposites using a sol-gel method. Transparent cellulose-POSS-amine-silica/titania hybrids were prepared by an in-situ sol-gel process in the presence of γ-aminopropyltrimethoxylsilane (γ-APTES). The methodology involves the formation of covalent bonding between the cellulose-POSS amine and SiO2/TiO2 hybrid nanocomposite material. An analysis of the synthesized hybrid material by Fourier transform infrared spectroscopy, X-ray diffraction, thermogravimetric analysis, differential thermal calorimetry, scanning electron microscopy, and transmission electron microscopy indicated that the silica/titania nanoparticles were bonded covalently and dispersed uniformly into the cellulose-POSS amine matrix. In addition, biological properties of the cellulose-POSS-silica/titania hybrid material were examined using an antimicrobial test against pathogenic bacteria, such as Bacillus cereus (F481072) and E. coli (ATCC35150) for the bacterial effect.

  13. Cellulose and 1,3-glucan synthesis during the early stages of wall regeneration in soybean protoplasts.

    Science.gov (United States)

    Klein, A S; Montezinos, D; Delmer, D P

    1981-06-01

    Protoplasts isolated from cultured soybean cells (Glycine max (L.) Merr., cv. Mandarin) were used to study polysaccharide biosynthesis during the initial stages of cell wall-regeneration. Within minutes after the protoplasts were transferred to a wall-regeneration medium containing [(14)C]glucose, radioactivity was detected in a product which was chemically characterized as cellulose. The onset and accumulation of radioactivity into cellulose coincided with the appearance fibrils on the surface of protoplasts, as seen under the electron microscope. At these early stages, a variety of polysaccharide-containing polymers other than cellulose were also synthesized. Under conditions where the protoplasts were competent to synthesize cellulose from glucose, uridine diphosphate-[(14)C]glucose and guanosine diphosphate-[(14)C]glucose did not serve as effective substrates for cellulose synthesis. However, substantial amounts of label from uridine diphosphate glucose were incorporated into 1,3-glucan.

  14. Polyoxometalate-mediated electron transfer-oxygen transfer oxidation of cellulose and hemicellulose to synthesis gas.

    Science.gov (United States)

    Sarma, Bidyut Bikash; Neumann, Ronny

    2014-08-01

    Terrestrial plants contain ~70% hemicellulose and cellulose that are a significant renewable bioresource with potential as an alternative to petroleum feedstock for carbon-based fuels. The efficient and selective deconstruction of carbohydrates to their basic components, carbon monoxide and hydrogen, so called synthesis gas, is an important key step towards the realization of this potential, because the formation of liquid hydrocarbon fuels from synthesis gas are known technologies. Here we show that by using a polyoxometalate as an electron transfer-oxygen transfer catalyst, carbon monoxide is formed by cleavage of all the carbon-carbon bonds through dehydration of initially formed formic acid. In this oxidation-reduction reaction, the hydrogen atoms are stored on the polyoxometalate as protons and electrons, and can be electrochemically released from the polyoxometalate as hydrogen. Together, synthesis gas is formed. In a hydrogen economy scenario, this method can also be used to convert carbon monoxide to hydrogen.

  15. Green synthesis of monodisperse silver nanoparticles using hydroxy propyl methyl cellulose

    Energy Technology Data Exchange (ETDEWEB)

    Dong, Chunfa; Zhang, Xianglin, E-mail: hust_zxl@mail.hust.edu.cn; Cai, Hao

    2014-01-15

    Graphical abstract: -- Highlights: • Synthesis of silver nanoparticles using hydroxy propyl methyl cellulose is reported. • HPMC and glucose are used as capping agent and reducing agent respectively. • It is the first time to use HPMC for synthesis of silver nanoparticles. • The small, spherical and well-dispersed particle is observed in the range of 3–17 nm. • The green method can be extended to other noble metals. -- Abstract: A simple and environmentally friendly method for the synthesis of highly stable and small sized silver nanoparticles with narrow distribution from 3 nm to 17 nm is reported. Silver nitrate, hydroxy propyl methyl cellulose (HPMC) and glucose, were used as silver precursor, capping agents and reducing agents respectively. The formation of silver nanoparticles was observed by change of color from colorless to wine red. The silver nanoparticles were characterized by transmission electron microscopy (TEM), UV–visible spectroscopy (UV–vis), X-ray diffraction (XRD) and Fourier-transform infrared spectroscopy (FT-IR). The results demonstrated that the obtained metallic nanoparticles were single crystalline silver nanoparticles capped with HPMC. The effects of the reaction time, reaction temperature and the concentration of silver ion and reducing agents on the particle size were investigated. A possible formation mechanism was proposed. The method may be extended to other noble metal for other technological applications such as additional medicinal, industrial applications.

  16. Synthesis and Characterization of Storage Energy Materials Prepared from Nano-crystalline Cellulose/Polyethylene Glycol

    Institute of Scientific and Technical Information of China (English)

    Xiao Ping YUAN; En Yong DING

    2006-01-01

    This paper gives a brief report of the synthesis of a new kind of solid-solid phase change materials (SSPCMs), nano-crystalline cellulose/polyethylene glycol (NCC/PEG). These PCMs have very high ability for energy storage, and their enthalpies reach 103.8 J/g. They are composed of two parts, PEG as functional branches for energy storage, and NCC as skeleton. The flexible polymer PEG was grafted onto the surface of rigid powder of NCC by covalent bonds. The results of DSC, FT-IR were briefly introduced, and some comments were also given.

  17. Synthesis, Antibacterial and Thermal Studies of Cellulose Nanocrystal Stabilized ZnO-Ag Heterostructure Nanoparticles

    OpenAIRE

    Mohd Zobir Hussein; Nor Azowa Ibrahim,; Mansor Bin Hj Ahmad; Susan Azizi

    2013-01-01

    Synthesis of ZnO-Ag heterostructure nanoparticles was carried out by a precipitation method with cellulose nanocrystals (CNCs) as a stabilizer for antimicrobial and thermal studies. ZnO-Ag nanoparticles were obtained from various weight percentages of added AgNO3 relative to Zn precursors for evaluating the best composition with enhanced functional properties. The ZnO-Ag/CNCs samples were characterized systematically by TEM, XRD, UV, TGA and DTG. From the TEM studies we observed that ZnO-Ag h...

  18. Peptide array on cellulose support--a screening tool to identify peptides with dipeptidyl-peptidase IV inhibitory activity within the sequence of α-lactalbumin.

    Science.gov (United States)

    Lacroix, Isabelle M E; Li-Chan, Eunice C Y

    2014-11-13

    The inhibition of the enzyme dipeptidyl-peptidase IV (DPP-IV) is an effective pharmacotherapeutic approach for the management of type 2 diabetes. Recent findings have suggested that dietary proteins, including bovine α-lactalbumin, could be precursors of peptides able to inhibit DPP-IV. However, information on the location of active peptide sequences within the proteins is far from being comprehensive. Moreover, the traditional approach to identify bioactive peptides from foods can be tedious and long. Therefore, the objective of this study was to use peptide arrays to screen α-lactalbumin-derived peptides for their interaction with DPP-IV. Deca-peptides spanning the entire α-lactalbumin sequence, with a frame shift of 1 amino acid between successive sequences, were synthesized on cellulose membranes using "SPOT" technology, and their binding to and inhibition of DPP-IV was studied. Among the 114 α-lactalbumin-derived decamers investigated, the peptides 60WCKDDQNPHS69 (αK(i) = 76 µM), 105LAHKALCSEK114 (K(i) = 217 µM) and 110LCSEKLDQWL119 (K(i) = 217 µM) were among the strongest DPP-IV inhibitors. While the SPOT- and traditionally-synthesized peptides showed consistent trends in DPP-IV inhibitory activity, the cellulose-bound peptides' binding behavior was not correlated to their ability to inhibit the enzyme. This research showed, for the first time, that peptide arrays are useful screening tools to identify DPP-IV inhibitory peptides from dietary proteins.

  19. Synthesis, Antibacterial and Thermal Studies of Cellulose Nanocrystal Stabilized ZnO-Ag Heterostructure Nanoparticles

    Directory of Open Access Journals (Sweden)

    Mohd Zobir Hussein

    2013-05-01

    Full Text Available Synthesis of ZnO-Ag heterostructure nanoparticles was carried out by a precipitation method with cellulose nanocrystals (CNCs as a stabilizer for antimicrobial and thermal studies. ZnO-Ag nanoparticles were obtained from various weight percentages of added AgNO3 relative to Zn precursors for evaluating the best composition with enhanced functional properties. The ZnO-Ag/CNCs samples were characterized systematically by TEM, XRD, UV, TGA and DTG. From the TEM studies we observed that ZnO-Ag heterostructure nanoparticles have spherical shapes with size diameters in a 9–35 nm range. The antibacterial activities of samples were assessed against the bacterial species Salmonella choleraesuis and Staphylococcus aureus. The CNC-stabilized ZnO-Ag exhibited greater bactericidal activity compared to cellulose-free ZnO-Ag heterostructure nanoparticles of the same particle size. The incorporation of ZnO-Ag hetreostructure nanoparticles significantly increased the thermal stability of cellulose nanocrystals.

  20. Importance of two consecutive methionines at the N-terminus of a cellulose synthase (PtdCesA8A) for normal wood cellulose synthesis in aspen.

    Science.gov (United States)

    Liu, Yunxia; Xu, Fuyu; Gou, Jiqing; Al-Haddad, Jameel; Telewski, Frank W; Bae, Hyeun-Jong; Joshi, Chandrashekhar P

    2012-11-01

    All known orthologs of a secondary wall-associated cellulose synthase (CesA) gene from Arabidopsis, AtCesA8, encode CesA proteins with two consecutive methionines at their N-termini (MM or 2M). Here, we report that these 2Ms in an aspen ortholog of AtCesA8, PtdCesA8A, are important for maintaining normal wood cellulose biosynthesis in aspen trees. Overexpression of an altered PtdCesA8A cDNA encoding a PtdCesA8A protein missing one methionine at the N-terminus (1M) in aspen resulted in substantial decrease in cellulose content and caused negative effects on wood strength, suggesting that both methionines are essential for proper CesA expression and function in developing xylem tissues. Transcripts from a pair of paralogous native PtdCesA8 genes, as well as introduced PtdCesA8A:1M transgenes were significantly reduced in developing xylem tissues of transgenic aspen plants, suggestive of a co-suppression event. Overexpression of a native PtdCesA8A cDNA encoding a CesA protein with 2Ms at the N-terminus did not cause any such phenotypic changes. These results suggest the importance of 2Ms present at the N-terminus of PtdCesA8A protein during cellulose synthesis in aspen.

  1. A Structural Study of CESA1 Catalytic Domain of Arabidopsis Cellulose Synthesis Complex: Evidence for CESA Trimers.

    Science.gov (United States)

    Vandavasi, Venu Gopal; Putnam, Daniel K; Zhang, Qiu; Petridis, Loukas; Heller, William T; Nixon, B Tracy; Haigler, Candace H; Kalluri, Udaya; Coates, Leighton; Langan, Paul; Smith, Jeremy C; Meiler, Jens; O'Neill, Hugh

    2016-01-01

    A cellulose synthesis complex with a "rosette" shape is responsible for synthesis of cellulose chains and their assembly into microfibrils within the cell walls of land plants and their charophyte algal progenitors. The number of cellulose synthase proteins in this large multisubunit transmembrane protein complex and the number of cellulose chains in a microfibril have been debated for many years. This work reports a low resolution structure of the catalytic domain of CESA1 from Arabidopsis (Arabidopsis thaliana; AtCESA1CatD) determined by small-angle scattering techniques and provides the first experimental evidence for the self-assembly of CESA into a stable trimer in solution. The catalytic domain was overexpressed in Escherichia coli, and using a two-step procedure, it was possible to isolate monomeric and trimeric forms of AtCESA1CatD. The conformation of monomeric and trimeric AtCESA1CatD proteins were studied using small-angle neutron scattering and small-angle x-ray scattering. A series of AtCESA1CatD trimer computational models were compared with the small-angle x-ray scattering trimer profile to explore the possible arrangement of the monomers in the trimers. Several candidate trimers were identified with monomers oriented such that the newly synthesized cellulose chains project toward the cell membrane. In these models, the class-specific region is found at the periphery of the complex, and the plant-conserved region forms the base of the trimer. This study strongly supports the "hexamer of trimers" model for the rosette cellulose synthesis complex that synthesizes an 18-chain cellulose microfibril as its fundamental product.

  2. Facile synthesis of TiO2/microcrystalline cellulose nanocomposites: photocatalytically active material under visible light irradiation

    Science.gov (United States)

    Doped TiO2 nanocomposites were prepared in situ by a facile and simple synthesis utilizing benign and renewable precursors such as microcrystalline cellulose (MC) and TiCl4 through hydrolysis in alkaline medium without the addition of organic solvents. The as-prepared nanocompos...

  3. Facile synthesis of TiO2/microcrystalline cellulose nanocomposites: photocatalytically active material under visible light irradiation

    Science.gov (United States)

    Doped TiO2 nanocomposites were prepared in situ by a facile and simple synthesis utilizing benign and renewable precursors such as microcrystalline cellulose (MC) and TiCl4 through hydrolysis in alkaline medium without the addition of organic solvents. The as-prepared nanocompos...

  4. Synthesis of cellulose triacetate from cotton cellulose by using NIS as a catalyst under mild reaction conditions.

    Science.gov (United States)

    El Nemr, Ahmed; Ragab, Safaa; El Sikaily, Amany; Khaled, Azza

    2015-10-05

    This research discusses the acetylation of cotton cellulose with acetic anhydride without solvents. The acetylation was done in the presence of different amounts of N-Iodosuccinimide (NIS) as a catalyst; this took place under mild reaction conditions. The extent of acetylation was measured by the weight percent gain (WPG) that varied from 24.71 to 71.83%. Cotton cellulose acetates, with the degree of substitution (DS) that ranged from 0.89 to 2.84, were prepared in one step. The cellulose triacetate, with a degree of substitution (DS) 2.84, was obtained. The WPG and DS were easily controlled by changing the reaction duration (1-5h), and the concentration of the catalyst (0.05 g, 0.075 g and 0.10 g for 1g of cellulose) in 25 ml of acetic anhydride. NIS was recognized as a novel and more successful catalyst for the acetylation of hydroxyl groups in cotton cellulose. Formation of the acetates and the calculation of the degree of substitution were performed by FT-IR, Raman, and (1)H NMR.

  5. Synthesis and properties of regenerated cellulose-based hydrogels with high strength and transparency for potential use as an ocular bandage

    Energy Technology Data Exchange (ETDEWEB)

    Patchan, M. [Research and Exploratory Development Department, The Johns Hopkins University Applied Physics Laboratory, 11100 Johns Hopkins Road, Laurel, MD 20723 (United States); Graham, J.L. [Department of Biomedical Engineering, Johns Hopkins University, School of Medicine, 720 Rutland Avenue/Ross 720, Baltimore, MD 21205 (United States); Xia, Z.; Maranchi, J.P. [Research and Exploratory Development Department, The Johns Hopkins University Applied Physics Laboratory, 11100 Johns Hopkins Road, Laurel, MD 20723 (United States); McCally, R. [Research and Exploratory Development Department, The Johns Hopkins University Applied Physics Laboratory, 11100 Johns Hopkins Road, Laurel, MD 20723 (United States); Wilmer Eye Institute, Johns Hopkins Medical Institutions, 600 N. Wolfe Street, Baltimore, MD 21287 (United States); Schein, O. [Wilmer Eye Institute, Johns Hopkins Medical Institutions, 600 N. Wolfe Street, Baltimore, MD 21287 (United States); Elisseeff, J.H. [Department of Biomedical Engineering, Johns Hopkins University, School of Medicine, 720 Rutland Avenue/Ross 720, Baltimore, MD 21205 (United States); Trexler, M.M., E-mail: morgana.trexler@jhuapl.edu [Research and Exploratory Development Department, The Johns Hopkins University Applied Physics Laboratory, 11100 Johns Hopkins Road, Laurel, MD 20723 (United States)

    2013-07-01

    Cellulose is a biologically derived material with excellent wound-healing properties. The high strength of cellulose fibers and the ability to synthesize gels with high optical transparency make these materials suitable for ocular applications. In this study, cellulose materials derived from wood pulp, cotton, and bacterial sources were dissolved in lithium chloride/N,N-dimethylacetamide to form regenerated cellulose hydrogels. Material properties of the resulting hydrogels, including water content, optical transparency, and tensile and tear strengths, were evaluated. Synthesis parameters, including activation time, dissolution time, relative humidity, and cellulose concentration, were found to impact the material properties of the resulting hydrogels. Overnight activation time improves the optical transparency of the hydrogels from 77% to 97% at 550 nm, whereas controlling cellulose concentration improves their tear strength by as much as 200%. On the basis of the measured transmittance and strength values of the regenerated hydrogels prepared via the optimized synthesis parameters, Avicel PH 101, Sigma-Aldrich microcrystalline cellulose 435236, and bacterial cellulose types were prioritized for future biocompatibility testing and potential clinical investigation. - Highlights: • Hydrogels were prepared (via LiCl/DMAc) from 7 different types of cellulose. • Synthesis parameters (activation, gelation, and concentration) were optimized. • Impact of synthesis parameters on transparency and strength was explored.

  6. One-step green synthesis of non-hazardous dicarboxyl cellulose flocculant and its flocculation activity evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Hangcheng; Zhang, Yong; Yang, Xiaogang; Liu, Hongyi [The Key Laboratory of Advanced Textile Materials and Manufacturing Technology of Ministry of Education, College of Materials and Textiles, Zhejiang Sci-Tech University, Hangzhou 310018 (China); Shao, Lan [Technique Center, Hangzhou Xinhua Group Co., Ltd, Hangzhou 310011 (China); Zhang, Xiumei [The Key Laboratory of Advanced Textile Materials and Manufacturing Technology of Ministry of Education, College of Materials and Textiles, Zhejiang Sci-Tech University, Hangzhou 310018 (China); Yao, Juming, E-mail: yaoj@zstu.edu.cn [The Key Laboratory of Advanced Textile Materials and Manufacturing Technology of Ministry of Education, College of Materials and Textiles, Zhejiang Sci-Tech University, Hangzhou 310018 (China)

    2015-10-15

    The waste management of used flocculants is a thorny issue in the field of wastewater treatment. To natural cellulose based flocculants, utilization of hazardous cellulose solvent and simplification of synthetic procedure are the two urgent problems needing to be further improved. In this work, a series of natural dicarboxyl cellulose flocculants (DCCs) were one-step synthesized via Schiff-base route. The cellulose solvent (NaOH/Urea solution) was utilized during the synthesis process. The full-biodegradable flocculants avoid causing secondary pollution to environment. The chemical structure and solution property of the DCC products were characterized by FT-IR, {sup 1}H NMR, {sup 13}C NMR, TGA, FESEM, charge density and ζ-potential. Kaolin suspension and effluent from paper mill were selected to evaluate the flocculation activity of the DCCs. Their flocculation performance was compared with that of commercial cationic polyacrylamide and poly aluminium chloride flocculants. The positive results showed that the NaOH/Urea solvent effectively promoted the dialdehyde cellulose (DAC) conversion to DCC in the one-step synthesis reaction. The DCCs with the carboxylate content more than 1 mmol/g exhibited steady flocculation performance to kaolin suspension in the broad pH range from 4 to 10. Its flocculation capacity to the effluent from paper mill also showed excellent.

  7. One-step green synthesis of non-hazardous dicarboxyl cellulose flocculant and its flocculation activity evaluation.

    Science.gov (United States)

    Zhu, Hangcheng; Zhang, Yong; Yang, Xiaogang; Liu, Hongyi; Shao, Lan; Zhang, Xiumei; Yao, Juming

    2015-10-15

    The waste management of used flocculants is a thorny issue in the field of wastewater treatment. To natural cellulose based flocculants, utilization of hazardous cellulose solvent and simplification of synthetic procedure are the two urgent problems needing to be further improved. In this work, a series of natural dicarboxyl cellulose flocculants (DCCs) were one-step synthesized via Schiff-base route. The cellulose solvent (NaOH/Urea solution) was utilized during the synthesis process. The full-biodegradable flocculants avoid causing secondary pollution to environment. The chemical structure and solution property of the DCC products were characterized by FT-IR, (1)H NMR, (13)C NMR, TGA, FESEM, charge density and ζ-potential. Kaolin suspension and effluent from paper mill were selected to evaluate the flocculation activity of the DCCs. Their flocculation performance was compared with that of commercial cationic polyacrylamide and poly aluminium chloride flocculants. The positive results showed that the NaOH/Urea solvent effectively promoted the dialdehyde cellulose (DAC) conversion to DCC in the one-step synthesis reaction. The DCCs with the carboxylate content more than 1 mmol/g exhibited steady flocculation performance to kaolin suspension in the broad pH range from 4 to 10. Its flocculation capacity to the effluent from paper mill also showed excellent.

  8. Synthesis of a novel acrylated abietic acid-g-bacterial cellulose hydrogel by gamma irradiation.

    Science.gov (United States)

    Abeer, Muhammad Mustafa; Amin, Mohd Cairul Iqbal Mohd; Lazim, Azwan Mat; Pandey, Manisha; Martin, Claire

    2014-09-22

    Acrylated abietic acid (acrylated AbA) and acrylated abietic acid-grafted bacterial cellulose pH sensitive hydrogel (acrylated AbA-g-BC) were prepared by a one-pot synthesis. The successful dimerization of acrylic acid (AA) and abietic acid (AbA) and grafting of the dimer onto bacterial cellulose (BC) was confirmed by 13C solid state NMR as well as FT-IR. X-ray diffraction analysis showed characteristic peaks for AbA and BC; further, there was no effect of increasing amorphous AA content on the overall crystallinity of the hydrogel. Differential scanning calorimetry revealed a glass transition temperature of 80°C. Gel fraction and swelling studies gave insight into the features of the hydrogel, suggesting that it was suitable for future applications such as drug delivery. Scanning electron microscopy observations showed an interesting interpenetrating network within the walls of hydrogel samples with the lowest levels of AA and gamma radiation doses. Cell viability test revealed that the synthesized hydrogel is safe for future use in biomedical applications.

  9. Plackett-Burman experimental design for bacterial cellulose-silica composites synthesis.

    Science.gov (United States)

    Guzun, Anicuta Stoica; Stroescu, Marta; Jinga, Sorin Ion; Voicu, Georgeta; Grumezescu, Alexandru Mihai; Holban, Alina Maria

    2014-09-01

    Bacterial cellulose-silica hybrid composites were prepared starting from wet bacterial cellulose (BC) membranes using Stöber reaction. The structure and surface morphology of hybrid composites were examined by FTIR and SEM. The SEM pictures revealed that the silica particles are attached to BC fibrils and are well dispersed in the BC matrix. The influence of silica particles upon BC crystallinity was studied using XRD analysis. Thermogravimetric (TG) analysis showed that the composites are stable up to 300°C. A Plackett-Burman design was applied in order to investigate the influence of process parameters upon silica particle sizes and silica content of BC-silica composites. The statistical model predicted that it is possible for silica particles size to vary the synthesis parameters in order to obtain silica particles deposed on BC membranes in the range from 34.5 to 500 nm, the significant parameters being ammonia concentration, reaction time and temperature. The silica content also varies depending on process parameters, the statistical model predicting that the most influential parameters are water-tetraethoxysilane (TEOS) ratio and reaction temperature. The antimicrobial behavior on Staphylococcus aureus of BC-silica composites functionalized with usnic acid (UA) was also studied, in order to create improved surfaces with antiadherence and anti-biofilm properties.

  10. Bacterial cellulose synthesis mechanism of facultative anaerobe Enterobacter sp. FY-07.

    Science.gov (United States)

    Ji, Kaihua; Wang, Wei; Zeng, Bing; Chen, Sibin; Zhao, Qianqian; Chen, Yueqing; Li, Guoqiang; Ma, Ting

    2016-02-25

    Enterobacter sp. FY-07 can produce bacterial cellulose (BC) under aerobic and anaerobic conditions. Three potential BC synthesis gene clusters (bcsI, bcsII and bcsIII) of Enterobacter sp. FY-07 have been predicted using genome sequencing and comparative genome analysis, in which bcsIII was confirmed as the main contributor to BC synthesis by gene knockout and functional reconstitution methods. Protein homology, gene arrangement and gene constitution analysis indicated that bcsIII had high identity to the bcsI operon of Enterobacter sp. 638; however, its arrangement and composition were same as those of BC synthesizing operon of G. xylinum ATCC53582 except for the flanking sequences. According to the BC biosynthesizing process, oxygen is not directly involved in the reactions of BC synthesis, however, energy is required to activate intermediate metabolites and synthesize the activator, c-di-GMP. Comparative transcriptome and metabolite quantitative analysis demonstrated that under anaerobic conditions genes involved in the TCA cycle were downregulated, however, genes in the nitrate reduction and gluconeogenesis pathways were upregulated, especially, genes in three pyruvate metabolism pathways. These results suggested that Enterobacter sp. FY-07 could produce energy efficiently under anaerobic conditions to meet the requirement of BC biosynthesis.

  11. Cellulose Acetate Sulfate as a Lyotropic Liquid Crystalline Polyelectrolyte: Synthesis, Properties, and Application

    Directory of Open Access Journals (Sweden)

    D. D. Grinshpan

    2010-01-01

    Full Text Available The optimal conditions of cellulose acetate sulfate (CAS homogeneous synthesis with the yield of 94–98 wt.% have been determined. CAS was confirmed to have an even distribution of functional groups along the polymer chain. The polymer was characterized by an exceptionally high water solubility (up to 70 wt.%. The isothermal diagrams of its solubility in water-alcohol media have been obtained. CAS aqueous solutions stability, electrolytic, thermal, and viscous properties have been defined. The main hydrodynamic characteristics such as intrinsic viscosity, Huggins constant, and crossover concentration have been evaluated. The parameters of polymer chain thermodynamic rigidity have been calculated. The formation of liquid crystalline structures in concentrated CAS solutions has been confirmed. CAS was recommended to be used as a binder for the medicinal forms of activated carbon and carbon sorbent for water treatment, hydrophilic ointment foundation.

  12. Green thermal-assisted synthesis and characterization of novel cellulose-Mg(OH)2 nanocomposite in PEG/NaOH solvent.

    Science.gov (United States)

    Ponomarev, Nikolai; Repo, Eveliina; Srivastava, Varsha; Sillanpää, Mika

    2017-11-15

    Synthesis of nanocomposites was performed using microcrystalline cellulose (MCC), MgCl2 in PEG/NaOH solvent by a thermal-assisted method at different temperatures by varying time and the amount of MCC. Results of XRD, FTIR, and EDS mapping showed that the materials consisted of only cellulose (CL) and magnesium hydroxide (MH). According to FTIR and XRD, it was found that crystallinity of MH in cellulose nanocomposites is increased with temperature and heating time and decreased with increasing of cellulose amount. The PEG/NaOH solvent has a significant effect on cellulose and Mg(OH)2 morphology. BET and BJH results demonstrated the effects of temperature and cellulose amount on the pore size corresponding to mesoporous materials. TG and DTG analyses showed the increased thermal stability of cellulose nanocomposites with increasing temperature. TEM and SEM analyses showed an even distribution of MH nanostructures with various morphology in the cellulose matrix. The cellulose presented as the polymer matrix in the nanocomposites. It was supposed the possible interaction between cellulose and Mg(OH)2. The novel synthesis method used in this study is feasible, cost-efficient and environmentally friendly. Copyright © 2017 Elsevier Ltd. All rights reserved.

  13. Synthesis and in vitro growth inhibitory activity of novel silyl- and trityl-modified nucleosides

    CSIR Research Space (South Africa)

    Panayides, Jenny-Lee

    2016-06-01

    Full Text Available -Farkas d, Hajierah Davids d,e , Leonie Harmse d , M. E. Christine Rey f , Ivan R. Green g, Stephen C. Pelly g, Robert Kiss c, Alexander Kornienko h, Willem A. L. van Otterlo a,g,⇑ a Molecular Sciences Institute, School of Chemistry, University... & Medicinal Chemistry 24 (2016) 2716–2724 Synthesis and in vitro growth inhibitory activity of novel silyl- and trityl-modified nucleosides Jenny-Lee Panayides a,b, Véronique Mathieu c, Laetitia Moreno Y. Banuls c, Helen Apostolellis d, Nurit Dahan...

  14. Facile and green synthesis of cellulose nanocrystal-supported gold nanoparticles with superior catalytic activity.

    Science.gov (United States)

    Yan, Wei; Chen, Chang; Wang, Ling; Zhang, Dan; Li, Ai-Jun; Yao, Zheng; Shi, Li-Yi

    2016-04-20

    The emphasis of science and technology shifts toward environmentally friendly and sustainable resources and processes. Herein, we report a facile, one-pot and green synthesis of biomaterial-supported gold nanoparticles (AuNPs) with superior catalytic activity. Cellulose nanocrystal (CNC)-supported AuNPs were prepared by heating the aqueous mixture of HAuCl4, CNCs and polyethylene glycol, avoiding toxic chemicals, extreme condition and complicated procedure. The resultant CNC-supported AuNPs exhibited catalytic activities for the reduction of 4-nitrophenol by sodium borohydride. The maximum apparent rate constant reached 1.47×10(-2)s(-1), and the turnover frequency reached 641h(-1). The superior catalytic performance can be ascribed to the large amount of highly dispersed AuNPs with few nanometers in size which are loaded on CNCs. About 90% of the AuNPs are smaller than 10nm, and nearly 60% of the AuNPs are smaller than 5nm. The synthesis is eco-friendly, facile and low-cost, thus has great potential for industrial and medical applications.

  15. Synthesis of SiC/Ag/Cellulose Nanocomposite and Its Antibacterial Activity by Reactive Oxygen Species Generation

    Directory of Open Access Journals (Sweden)

    Andrzej Borkowski

    2016-09-01

    Full Text Available We describe the synthesis of nanocomposites, based on nanofibers of silicon carbide, silver nanoparticles, and cellulose. Silver nanoparticle synthesis was achieved with chemical reduction using hydrazine by adding two different surfactants to obtain a nanocomposite with silver nanoparticles of different diameters. Determination of antibacterial activity was based on respiration tests. Enzymatic analysis indicates oxidative stress, and viability testing was conducted using an epifluorescence microscope. Strong bactericidal activity of nanocomposites was found against bacteria Escherichia coli and Bacillus cereus, which were used in the study as typical Gram-negative and Gram-positive bacteria, respectively. It is assumed that reactive oxygen species generation was responsible for the observed antibacterial effect of the investigated materials. Due to the properties of silicon carbide nanofiber, the obtained nanocomposite may have potential use in technology related to water and air purification. Cellulose addition prevented silver nanoparticle release and probably enhanced bacterial adsorption onto aggregates of the nanocomposite material.

  16. Effects of Increased Night Temperature on Cellulose Synthesis and the Activity of Sucrose Metabolism Enzymes in Cotton Fiber

    Institute of Scientific and Technical Information of China (English)

    TIAN Jing-shan; HU Yuan-yuan; GAN Xiu-xia; ZHANG Ya-li; HU Xiao-bing; GOU Ling; LUO Hong-hai; ZHANG Wang-feng

    2013-01-01

    Temperature is one of the key factors that influence cotton fiber synthesis at the late growth stage of cotton. In this paper, using two early-maturing cotton varieties as experimental materials, night temperature increase was stimulated in the field using far-infrared quartz tubes set in semi-mobile incubators and compared with the normal night temperatures (control) in order to investigate the effects of night temperature on the cotton fiber cellulose synthesis during secondary wall thickening. The results showed that the activity of sucrose synthase (SuSy) and sucrose phosphate synthase (SPS) quickly increased and remained constant during the development of cotton fiber, while the activity of acid invertase (AI) and alkaline invertase (NI) decreased, increased night temperatures prompted the rapid transformation of sugar, and all the available sucrose fully converted into cellulose. With night temperature increasing treatment, an increase in SuSy activity and concentration of sucrose indicate more sucrose converted into UDPG (uridin diphosphate-glucose) during the early and late stages of cotton fiber development. Furthermore, SPS activity and the increased concentration of fructose accelerated fructose degradation and reduced the inhibition of fructose to SuSy; maintaining higher value of allocation proportion of invertase and sucrose during the early development stages of cotton fiber, which was propitious to supply a greater carbon source and energy for cellulose synthesis. Therefore, the minimum temperature in the nightime was a major factor correlated with the activity of sucrose metabolism enzymes in cotton fiber. Consequently, soluble sugar transformation and cellulose accumulation were closely associated with the minimum night temperature.

  17. In situ synthesis of polysaccharide nanoparticles via polyion complex of carboxymethyl cellulose and chitosan.

    Science.gov (United States)

    Kaihara, Sachiko; Suzuki, Yoichi; Fujimoto, Keiji

    2011-07-01

    Biocompatible polymer-magnetite hybrid nanoparticles were prepared by means of in situ synthesis of magnetite within polysaccharide hydrogel nanoparticles. Hydrogel nanoparticles were first fabricated by blending high-molecular-weight carboxymethyl cellulose as an anionic polymer, and low-molecular-weight chitosan as a cationic polymer to form polyion complexes (CC particles). These polyion complexes were then chemically crosslinked using genipin, a bio-based cross-linker, to form stable nanoparticles having a semi-IPN structure (CCG particles). Magnetite was lastly synthesized within CCG particles by the coprecipitation method to obtain polymer-magnetite hybrid nanoparticles (CCGM particles). The formations of CC, CCG and CCGM particles were mainly observed by transmittance, absorbance of genipin and TEM, respectively, and their hydrodynamic diameters and zeta-potentials were analyzed. It was confirmed that the hydrodynamic diameters and the zeta-potentials of these particles were significantly influenced by pH of the suspension, which was attributed to the charges of polymers. The diameters of CCGM particles were smaller than 200 nm at any pH conditions, suggesting the possibility to apply them as drug delivery carriers. CCGM particles exhibited the responsiveness to a magnetic field in addition to their high dispersion stability, indicating their potential to be utilized as a biomaterial for hyperthermia.

  18. Green synthesis of hybrid graphene oxide/microcrystalline cellulose aerogels and their use as superabsorbents

    Energy Technology Data Exchange (ETDEWEB)

    Wei, Xiao; Huang, Ting; Yang, Jing-hui; Zhang, Nan; Wang, Yong, E-mail: yongwang1976@163.com; Zhou, Zuo-wan

    2017-08-05

    Highlights: • Hybrid GO/MCC aerogels were prepared using LiBr aqueous solution as the solvent. • GO was exfoliated by MCC through the strong interaction between them. • The adsorption ability of GO per unit mass in the hybrid aerogels was greatly enhanced. - Abstract: In this work, we developed a green synthesis method to prepare the hybrid aerogels containing graphene oxide (GO) and microcrystalline cellulose (MCC) using lithium bromide (LiBr) aqueous solution as the solvent, which insured the complete dissolution of MCC. The interaction between GO and MCC was investigated through different methods The results demonstrate that there is a strong interaction between GO and MCC molecules, which promotes the exfoliation of GO in the hybrid aerogels. The hybrid GO/MCC aerogels exhibit typical three dimensional porous structure and the pore morphology can be well adjusted by changing the content of GO. The adsorption ability of the hybrid aerogels was measured using methylene blue (MB) as an adsorbate. The results show that the adsorption ability of GO per unit mass is greatly enhanced compared with the pure GO aerogel, especially at relatively low GO content the adsorption amount of GO per unit mass is enhanced up to 2630 mg/g. Further results demonstrate that the hybrid GO/MCC aerogels still obey the pseudo-second-order adsorption model, which is similar to that of the pure GO aerogel. The mechanism for the amplified adsorption ability of GO in the hybrid GO/MCC aerogels is then analyzed.

  19. Synthesis and Catalytic Features of Hybrid Metal Nanoparticles Supported on Cellulose Nanofibers

    Directory of Open Access Journals (Sweden)

    Hirotaka Koga

    2011-11-01

    Full Text Available The structural and functional design of metal nanoparticles has recently allowed remarkable progress in the development of high-performance catalysts. Gold nanoparticles (AuNPs are among the most innovative catalysts, despite bulk Au metal being regarded as stable and inactive. The hybridization of metal NPs has attracted major interest in the field of advanced nanocatalysts, due to electro-mediated ligand effects. In practical terms, metal NPs need to be supported on a suitable matrix to avoid any undesirable aggregation; many researchers have reported the potential of polymer-supported AuNPs. However, the use of conventional polymer matrices make it difficult to take full advantage of the inherent properties of the metal NPs, since most of active NPs are imbedded inside the polymer support. This results in poor accessibility for the reactants. Herein, we report the topochemical synthesis of Au and palladium (Pd bimetallic NPs over the surfaces of 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO-oxidized cellulose nanofibers (TOCNs, and their exceptional catalytic performance. Highly-dispersed AuPdNPs were successfully synthesized in situ on the crystal surfaces of TOCNs with a very high density of carboxylate groups. The AuPdNPs@TOCN nanocomposites exhibit excellent catalytic efficiencies in the aqueous reduction of 4-nitrophenol to 4-aminophenol, depending on the molar ratios of Au and Pd.

  20. Ionic Liquid-assisted Synthesis of Cellulose/TiO2 Composite and Photocatalytic Performance

    Directory of Open Access Journals (Sweden)

    ZHU Mo-shuqi

    2016-12-01

    Full Text Available Cellulose/TiO2 composite was prepared by sol-gel method using the ionic liquid BMIMCl as reactive medium and Ti(OBu4 as a precursor. The synthesis conditions were optimized by single-factor experiment. The structure and properties of the composite were characterized by scanning electron microscope (SEM,X-ray diffraction(XRD,Fourier transform infrared spectoscopy(FT-IR,UV-vis-diffuse reflectance spectroscope(DRS and thermogravimetric (TG analysis. The photocatalytic activity of the composite was investigated via testing the photodegradation of methyl orange in aqueous suspension under UV-light. The results show that the high active photocatalytic composite is prepared by using ionic liquid BMIMCl as medium at room temperature and atmospheric pressure. The photo catalytic degradation rate of composite on methyl orange(MO reaches 97.09% in 80min. Comparing with bare TiO2, the degradation rate of MO increases by 37%. Moreover, the composite still shows 62.66% degradation rate towards MO after recycling 4 times.

  1. Superabsorbent nanocomposite synthesis of cellulose from rice husk grafted poly(acrylate acid-co-acrylamide)/bentonite

    Science.gov (United States)

    Helmiyati; Abbas, G. H.; Kurniawan, S.

    2017-04-01

    Superabsorbent nanocomposite synthesis of cellulose rice husk as the backbone with free radical polymerization method in copolymerization grafted with acrylic acid and acrylamide monomer. The cellulose was isolated from rice husk with mixture of toluene and ethanol and then hemicellulose and lignin were removed by using potassium hydroxide 4% and hydrogen peroxide 2%. The obtained cellulose rendement was 37.85%. The functional group of lignin analyzed by FTIR spectra was disappeared at wavenumber 1724 cm-1. Crystal size of the obtained isolated cellulose analyzed by XRD diffraction pattern was 34.6 nm, indicated the nanocrystal structure. Copolymerization was performed at temperature of 70°C with flow nitrogen gas. Initiator and crosslinking agent used were potassium persulfate and N‧N-methylene-bis-acrylamide. The swelling capacity of water and urea showed the results was quite satisfactory, the maximum swelling capacity in urea and water were 611.700 g/g and 451.303 g/g, respectively, and can be applied in agriculture to absorb water and urea fertilizer.

  2. A novel process for synthesis of spherical nanocellulose by controlled hydrolysis of microcrystalline cellulose using anaerobic microbial consortium.

    Science.gov (United States)

    Satyamurthy, P; Vigneshwaran, N

    2013-01-10

    Degradation of cellulose by anaerobic microbial consortium is brought about either by an exocellular process or by secretion of extracellular enzymes. In this work, a novel route for synthesis of nanocellulose is described where in an anaerobic microbial consortium enriched for cellulase producers is used for hydrolysis. Microcrystalline cellulose derived from cotton fibers was subjected to controlled hydrolysis by the anaerobic microbial consortium and the resultant nanocellulose was purified by differential centrifugation technique. The nanocellulose had a bimodal size distribution (43±13 and 119±9 nm) as revealed by atomic force microscopy. A maximum nanocellulose yield of 12.3% was achieved in a span of 7 days. While the conventional process of nanocellulose preparation using 63.5% (w/w) sulfuric acid resulted in the formation of whisker shaped nanocellulose with surface modified by sulfation, controlled hydrolysis by anaerobic microbial consortium yielded spherical nanocellulose also referred to as nano crystalline cellulose (NCC) without any surface modification as evidenced from Fourier transform infrared spectroscopy. Also, it scores over chemo-mechanical production of nanofibrillated cellulose by consuming less energy due to enzyme (cellulase) assisted catalysis. This implies the scope for use of microbial prepared nanocellulose in drug delivery and bio-medical applications requiring bio-compatibility. Copyright © 2012 Elsevier Inc. All rights reserved.

  3. SYNTHESIS AND CHARACTERIZATION OF CELLULOSE-SILICA COMPOSITE FIBER IN ETHANOL/WATER MIXED SOLVENTS

    Directory of Open Access Journals (Sweden)

    Ning Jia

    2011-04-01

    Full Text Available Cellulose-silica composite fiber samples have been successfully synthesized using cellulose solution, tetraethoxysilane, and NH3•H2O in ethanol/water mixed solvents at room temperature for 24 h. The cellulose solution was previously prepared by the dissolution of microcrystalline cellulose in a solvent mixture of N,N-dimethylacetamide (DMAc/lithium chloride (LiCl. The effect of the tetraethoxysilane concentration on the product was investigated. The products were characterized by X-ray powder diffraction (XRD, thermogravimetric analysis (TG, differential scanning calorimetric analysis (DSC, scanning electron microscopy (SEM, Fourier transform infrared spectrometry (FT-IR, energy-dispersive X-ray spectrum (EDS, and cross polarization magic angle spinning (CP/MAS solid state 13C-NMR. The morphology of the cellulose-silica composite fiber was investigated by SEM, while their composition was established from EDS measurements combined with the results of FT-IR spectral analysis and XRD patterns. The XRD, FT-IR and EDS results indicated that the obtained product was cellulose-silica composite fiber. The SEM micrographs showed that the silica particles were homogeneously dispersed in the cellulose fiber. The CP/MAS solid state 13C-NMR results indicated that the silica concentration had an influence on the crystallinity of the cellulose. This method is simple for preparation of cellulose-based composites.

  4. Perturbation of wood cellulose synthesis causes pleiotropic effects in transgenic aspen.

    Science.gov (United States)

    Joshi, Chandrashekhar P; Thammannagowda, Shivegowda; Fujino, Takeshi; Gou, Ji-Qing; Avci, Utku; Haigler, Candace H; McDonnell, Lisa M; Mansfield, Shawn D; Mengesha, Bemnet; Carpita, Nicholas C; Harris, Darby; Debolt, Seth; Peter, Gary F

    2011-03-01

    Genetic manipulation of cellulose biosynthesis in trees may provide novel insights into the growth and development of trees. To explore this possibility, the overexpression of an aspen secondary wall-associated cellulose synthase (PtdCesA8) gene was attempted in transgenic aspen (Populus tremuloides L.) and unexpectedly resulted in silencing of the transgene as well as its endogenous counterparts. The main axis of the transgenic aspen plants quickly stopped growing, and weak branches adopted a weeping growth habit. Furthermore, transgenic plants initially developed smaller leaves and a less extensive root system. Secondary xylem (wood) of transgenic aspen plants contained as little as 10% cellulose normalized to dry weight compared to 41% cellulose typically found in normal aspen wood. This massive reduction in cellulose was accompanied by proportional increases in lignin (35%) and non-cellulosic polysaccharides (55%) compared to the 22% lignin and 36% non-cellulosic polysaccharides in control plants. The transgenic stems produced typical collapsed or 'irregular' xylem vessels that had altered secondary wall morphology and contained greatly reduced amounts of crystalline cellulose. These results demonstrate the fundamental role of secondary wall cellulose within the secondary xylem in maintaining the strength and structural integrity required to establish the vertical growth habit in trees.

  5. Perturbation of Wood Cellulose Synthesis Causes Pleiotropic Effects in Transgenic Aspen

    Institute of Scientific and Technical Information of China (English)

    Chandrashekhar P.Joshi; Nicholas C.Carpita; Darby Harris; Seth DeBolt; Gary F.Peter; Shivegowda Thammannagowda; Takeshi Fujino; Ji-Qing Gou; Utku Avci; Candace H.Haigler; Lisa M.McDonnell; Shawn D.Mansfield; Bemnet Mengesha

    2011-01-01

    Genetic manipulation of cellulose biosynthesis in trees may provide novel insights into the growth and development of trees. To explore this possibility,the overexpression of an aspen secondary wall-associated cellulose syn-thase (PtdCesA8) gene was attempted in transgenic aspen (Populus tremuloides L.) and unexpectedly resulted in silencing of the transgene as well as its endogenous counterparts. The main axis of the transgenic aspen plants quickly stopped growing,and weak branches adopted a weeping growth habit. Furthermore,transgenic plants initially developed smaller leaves and a less extensive root system. Secondary xylem (wood) of transgenic aspen plants contained as little as 10% cellulose normalized to dry weight compared to 41% cellulose typically found in normal aspen wood. This massive reduction in cellulose was accompanied by proportional increases in lignin (35%) and non-cellulosic polysaccharides (55%) compared to the 22% lignin and 36% non-cellulosic polysaccharides in control plants. The transgenic stems produced typical collapsed or 'irregular' xylem vessels that had altered secondary wall morphology and contained greatly reduced amounts of crystalline cellulose. These results demonstrate the fundamental role of secondary wall cellulose within the secondary xylem in maintaining the strength and structural integrity required to establish the vertical growth habit in trees.

  6. Binding Cellulose and Chitosan via Intermolecular Inclusion Interaction: Synthesis and Characterisation of Gel

    OpenAIRE

    Jiufang Duan; Chunrui Han; Liujun Liu; Jianxin Jiang; Jianzhang Li; Yiqiang Li; Chao Guan

    2015-01-01

    A novel cellulose-chitosan gel was successfully prepared in three steps: (1) ferrocene- (Fc-) cellulose with degrees of substitution (DS) of 0.5 wt% was synthesised by ferrocenecarboxylic acid and cellulose within dimethylacetamide/lithium chloride (DMAc/LiCl); (2) the β-cyclodextrin (β-CD) groups were introduced onto the chitosan chains by reacting chitosan with epichlorohydrin in dimethyl sulphoxide and a DS of 0.35 wt%; (3) thus, the cellulose-chitosan gel was obtained via an intermolecula...

  7. Cellulose nanocrystals as templates for cetyltrimethylammonium bromide mediated synthesis of Ag nanoparticles and their novel use in PLA films.

    Science.gov (United States)

    Yalcinkaya, E E; Puglia, D; Fortunati, E; Bertoglio, F; Bruni, G; Visai, L; Kenny, J M

    2017-02-10

    In the present paper, we reported how cellulose nanocrystals (CNC) from microcrystalline cellulose have the capacity to assist in the synthesis of metallic nanoparticles chains. A cationic surfactant, cetyltrimethylammonium bromide (CTAB), was used as modifier for CNC surface. Silver nanoparticles were synthesized on CNC, and nanoparticle density and size were optimized by varying concentrations of nitrate and reducing agents, and the reduction time. The experimental conditions were optimized for the synthesis and the resulting Ag grafted CNC (Ag-g-CNC) were characterized by means of TGA, SEM, FTIR and XRD, and then introduced in PLA matrix. PLA nanocomposite containing silver grafted cellulose nanocrystals (PLA/0.5Ag-g-1CNC) was characterized by optical and thermal analyses and the obtained data were compared with results from PLA nanocomposites containing 1% wt. of CNC (PLA/1CNC), 0.5% wt. of silver nanoparticles (PLA/0.5Ag) and hybrid system containing CNC and silver in the same amount (PLA/1CNC/0.5Ag). The results demonstrated that grafting of silver nanoparticles on CNC positively affected the thermal degradation process and cold crystallization processes of PLA matrix. Finally, the antibacterial activity of the different systems was studied at various incubation times and temperatures, showing the best performance for PLA/1CNC/0.5Ag based nanocomposite. Copyright © 2016 Elsevier Ltd. All rights reserved.

  8. Green heterogeneous Pd(II) catalyst produced from chitosan-cellulose micro beads for green synthesis of biaryls.

    Science.gov (United States)

    Baran, Talat; Sargin, Idris; Kaya, Murat; Menteş, Ayfer

    2016-11-01

    In green catalyst systems, both the catalyst and the technique should be environmentally safe. In this study we designed a green palladium(II) catalyst for microwave-assisted Suzuki CC coupling reactions. The catalyst support was produced from biopolymers; chitosan and cellulose. The catalytic activity of the catalyst was tested on 16 substrates in solvent-free media and compared with those of commercial palladium salts. Reusability tests were done. The catalyst was also used in conventional reflux-heating system to demonstrate the efficiency of microwave heating method. We recorded high activity, selectivity and excellent TONs (6600) and TOFs (82500) just using a small catalyst loading (1.5×10(-3)mol%) in short reaction time (5min). The catalyst exhibited a long lifetime (9 runs). The findings indicated that both green chitosan/cellulose-Pd(II) catalyst and the microwave heating are suitable for synthesis of biaryl compounds by using Suzuki CC coupling reactions.

  9. Low cost hydrogen/novel membrane technology for hydrogen separation from synthesis gas, Phase 1. [Polyetherimide, cellulose acetate and ethylcellulose

    Energy Technology Data Exchange (ETDEWEB)

    1986-01-01

    The goal of this program is to develop polymer membranes useful in the preparation of hydrogen from coal-derived synthesis gas. During this quarter the first experiment were aimed at developing high performance composite membranes for the separation of hydrogen from nitrogen and carbon monoxide. Three polymers have been selected as materials for these membranes: polyetherimide cellulose acetate and ethylcellulose. This quarter the investigators worked on polyetherimide and cellulose acetate membranes. The overall structure of these membranes is shown schematically in Figure 1. As shown, a microporous support membrane is first coated with a high flux intermediate layer then with an ultrathin permselective layer and finally, if necessary, a thin protective high flux layer. 1 fig., 4 tabs.

  10. Synthesis and characterization of cellulose nanocrystal/graphene oxide blended films

    Science.gov (United States)

    Kafy, Abdullahil; Akther, Asma; Shishir, Md. I. R.; Jo, Eun Byul; Kim, Jaehwan

    2016-04-01

    Hybrid composites with organic and inorganic materials are drawing interest to researchers by adopting advantages of organic materials and inorganic materials. Cellulose is biocompatible, cheap, environmentally friendly, renewable and lightweight material. Nano crystalline form of cellulose (CNC) is a needle like rigid structure with a very high mechanical strength. Graphene, crystalline forms of carbon, provides basic platform for many electronic and optoelectronic devices. This paper introduces the fabrication process of cellulose nanocrystal/graphene oxide blended nanocomposite film. Cellulose nanocrystal/graphene oxide nanocomposite films are prepared by mixing graphene oxide (GO) into cellulose nanocrystal suspension using ultrasonic homogenizer. Scanning electron microscopy is used to study morphology. Optical properties of the composite was characterized to evaluate the change in transparency after addition of GO in CNC.

  11. GIL, a new c-di-GMP-binding protein domain involved in regulation of cellulose synthesis in enterobacteria.

    Science.gov (United States)

    Fang, Xin; Ahmad, Irfan; Blanka, Andrea; Schottkowski, Marco; Cimdins, Annika; Galperin, Michael Y; Römling, Ute; Gomelsky, Mark

    2014-08-01

    In contrast to numerous enzymes involved in c-di-GMP synthesis and degradation in enterobacteria, only a handful of c-di-GMP receptors/effectors have been identified. In search of new c-di-GMP receptors, we screened the Escherichia coli ASKA overexpression gene library using the Differential Radial Capillary Action of Ligand Assay (DRaCALA) with fluorescently and radioisotope-labelled c-di-GMP. We uncovered three new candidate c-di-GMP receptors in E. coli and characterized one of them, BcsE. The bcsE gene is encoded in cellulose synthase operons in representatives of Gammaproteobacteria and Betaproteobacteria. The purified BcsE proteins from E. coli, Salmonella enterica and Klebsiella pneumoniae bind c-di-GMP via the domain of unknown function, DUF2819, which is hereby designated GIL, GGDEF I-site like domain. The RxGD motif of the GIL domain is required for c-di-GMP binding, similar to the c-di-GMP-binding I-site of the diguanylate cyclase GGDEF domain. Thus, GIL is the second protein domain, after PilZ, dedicated to c-di-GMP-binding. We show that in S. enterica, BcsE is not essential for cellulose synthesis but is required for maximal cellulose production, and that c-di-GMP binding is critical for BcsE function. It appears that cellulose production in enterobacteria is controlled by a two-tiered c-di-GMP-dependent system involving BcsE and the PilZ domain containing glycosyltransferase BcsA.

  12. The Phytohormone Ethylene Enhances Cellulose Production, Regulates CRP/FNRKx Transcription and Causes Differential Gene Expression within the Bacterial Cellulose Synthesis Operon of Komagataeibacter (Gluconacetobacter) xylinus ATCC 53582.

    Science.gov (United States)

    Augimeri, Richard V; Strap, Janice L

    2015-01-01

    Komagataeibacter (formerly Gluconacetobacter) xylinus ATCC 53582 is a plant-associated model organism for bacterial cellulose (BC) biosynthesis. This bacterium inhabits the carposphere where it interacts with fruit through the bi-directional transfer of phytohormones. The majority of research regarding K. xylinus has been focused on identifying and characterizing structural and regulatory factors that control BC biosynthesis, but its ecophysiology has been generally overlooked. Ethylene is a phytohormone that regulates plant development in a variety of ways, but is most commonly known for its positive role on fruit ripening. In this study, we utilized ethephon (2-chloroethylphosphonic acid) to produce in situ ethylene to investigate the effects of this phytohormone on BC production and the expression of genes known to be involved in K. xylinus BC biosynthesis (bcsA, bcsB, bcsC, bcsD, cmcAx, ccpAx and bglAx). Using pellicle assays and reverse transcription quantitative polymerase chain reaction (RT-qPCR), we demonstrate that ethephon-derived ethylene enhances BC directly in K. xylinus by up-regulating the expression of bcsA and bcsB, and indirectly though the up-regulation of cmcAx, ccpAx, and bglAx. We confirm that IAA directly decreases BC biosynthesis by showing that IAA down-regulates bcsA expression. Similarly, we confirm that ABA indirectly influences BC biosynthesis by showing it does not affect the expression of bcs operon genes. In addition, we are the first to report the ethylene and indole-3-acetic acid (IAA) induced differential expression of genes within the bacterial cellulose synthesis (bcs) operon. Using bioinformatics we have identified a novel phytohormone-regulated CRP/FNRKx transcription factor and provide evidence that it influences BC biosynthesis in K. xylinus. Lastly, utilizing current and previous data, we propose a model for the phytohormone-mediated fruit-bacteria interactions that K. xylinus experiences in nature.

  13. The phytohormone ethylene enhances bacterial cellulose production, regulates CRP/FNRKx transcription and causes differential gene expression within the cellulose synthesis operon of Komagataeibacter (Gluconacetobacter xylinus ATCC 53582

    Directory of Open Access Journals (Sweden)

    Richard Vincent Augimeri

    2015-12-01

    Full Text Available Komagataeibacter (formerly Gluconacetobacter xylinus ATCC 53582 is a plant-associated model organism for bacterial cellulose (BC biosynthesis. This bacterium inhabits the carposphere where it interacts with fruit through the bi-directional transfer of phytohormones. The majority of research regarding K. xylinus has been focused on identifying and characterizing structural and regulatory factors that control BC biosynthesis, but its ecophysiology has been generally overlooked. Ethylene is a phytohormone that regulates plant development in a variety of ways, but is most commonly known for its positive role on fruit ripening. In this study, we utilized ethephon (2-chloroethylphosphonic acid to produce in situ ethylene to investigate the effects of this phytohormone on BC production and the expression of genes known to be involved in K. xylinus BC biosynthesis (bcsA, bcsB, bcsC, bcsD, cmcAx, ccpAx and bglAx. Using pellicle assays and reverse transcription quantitative polymerase chain reaction (RT-qPCR, we demonstrate that ethephon-derived ethylene enhances BC directly in K. xylinus by up-regulating the expression of bcsA and bcsB, and indirectly though the up-regulation of cmcAx, ccpAx and bglAx. We confirm that IAA directly decreases BC biosynthesis by showing that IAA down-regulates bcsA expression. Similarly, we confirm that ABA indirectly influences BC biosynthesis by showing it does not affect the expression of bcs operon genes. In addition, we are the first to report the ethylene and indole-3-acetic acid (IAA induced differential expression of genes within the bacterial cellulose synthesis (bcs operon. Using bioinformatics we have identified a novel phytohormone-regulated CRP/FNRKx transcription factor and provide evidence that it influences BC biosynthesis in K. xylinus. Lastly, utilizing current and previous data, we propose a model for the phytohormone-mediated fruit-bacteria interactions that K. xylinus experiences in nature.

  14. Habituation to thaxtomin A in hybrid poplar cell suspensions provides enhanced and durable resistance to inhibitors of cellulose synthesis

    Directory of Open Access Journals (Sweden)

    Beaulieu Carole

    2010-12-01

    Full Text Available Abstract Background Thaxtomin A (TA, a phytotoxin produced by the phytopathogen Streptomyces scabies, is essential for the development of potato common scab disease. TA inhibits cellulose synthesis but its actual mode of action is unknown. Addition of TA to hybrid poplar (Populus trichocarpa x Populus deltoides cell suspensions can activate a cellular program leading to cell death. In contrast, it is possible to habituate hybrid poplar cell cultures to grow in the presence of TA levels that would normally induce cell death. The purpose of this study is to characterize TA-habituated cells and the mechanisms that may be involved in enhancing resistance to TA. Results Habituation to TA was performed by adding increasing levels of TA to cell cultures at the time of subculture over a period of 12 months. TA-habituated cells were then cultured in the absence of TA for more than three years. These cells displayed a reduced size and growth compared to control cells and had fragmented vacuoles filled with electron-dense material. Habituation to TA was associated with changes in the cell wall composition, with a reduction in cellulose and an increase in pectin levels. Remarkably, high level of resistance to TA was maintained in TA-habituated cells even after being cultured in the absence of TA. Moreover, these cells exhibited enhanced resistance to two other inhibitors of cellulose biosynthesis, dichlobenil and isoxaben. Analysis of gene expression in TA-habituated cells using an Affymetrix GeneChip Poplar Genome Array revealed that durable resistance to TA is associated with a major and complex reprogramming of gene expression implicating processes such as cell wall synthesis and modification, lignin and flavonoid synthesis, as well as DNA and chromatin modifications. Conclusions We have shown that habituation to TA induced durable resistance to the bacterial toxin in poplar cells. TA-habituation also enhanced resistance to two other structurally

  15. Synthesis and Characterization of Cellulose Acetate from TCF Oil Palm Empty Fruit Bunch Pulp

    Directory of Open Access Journals (Sweden)

    Fauzi Muhammad Djuned

    2014-06-01

    Full Text Available Cellulose acetate (CA was successfully synthesized by the acetylation of TCF cellulose pulp from oil palm empty fruit bunches (OPEFB at room temperature, using acetic anhydride as the acetylating agent and acetic acid as the solvent in the presence of sulfuric acid/sodium bisulfate as catalysts. Degree of substitution (DS was controlled by the variables of acetylation time and acetic anhydride to cellulose ratio, under the heterogeneous state. The product (CA obtained was characterized through Fourier transform infrared spectroscopy (FTIR, nuclear magnetic resonance spectroscopy (NMR, differential scanning calorimetry (DSC, X-ray diffraction (XRD, and scanning electron microscopy (SEM. The results indicate that the CA obtained has characteristics similar to commercial CA, and DS is significantly dependent on acetylation time and the acetic anhydride-to-cellulose ratio.

  16. Synthesis, characterization, and reactivity of cellulose modified nano zero-valent iron for dye discoloration

    Science.gov (United States)

    Wang, Xiangyu; Wang, Pei; Ma, Jun; Liu, Huiling; Ning, Ping

    2015-08-01

    Nano zero-valent iron (NZVI) was innovatively and successfully modified by using hydroxyethyl cellulose (HEC) and hydroxypropylmethyl cellulose (HPMC) as dispersants. The systematic characterization observations (including XRD, SEM and TEM) illustrate that, compared with bare nano zero-valent iron particles (BNZVI), the particle sizes of hydroxyethyl cellulose modified (ENZVI) and hydroxypropylmethyl cellulose modified (PNZVI) were decreased, while the dispersity and antioxidizability of ENZVI and PNZVI particles were increased. The discoloration efficiencies of ENZVI, PNZVI, and BNZVI were compared by using dyes (including orange II, methyl orange, methyl blue, and methylene blue) as target pollutant. The results show that both the discoloration efficiency and reaction rate of ENZVI and PNZVI are higher than that of BNZVI. In addition, effects of dispersant content, dye type, pH value, initial dye concentration, iron dosage, and reaction temperature on discoloration efficiencies were studied. The results show that discoloration efficiency was decreased by increasing initial pH value and dye concentration, and it was increased with the increase the iron dosage and reaction temperature. Under optimized NZVI addition of 0.7 g L-1, the discoloration efficiencies of ENZVI and PNZVI were increased to 96.33% and 98.62%, respectively. And the possible discoloration pathway and dispersant modification mechanism of NZVI were discussed. This study suggests hydroxyethyl cellulose and hydroxypropylmethyl cellulose dispersed NZVI can be utilized as a promising modified nano-material for degradation of dye wastewater.

  17. Green synthesis of a typical chiral stationary phase of cellulose-tris(3, 5-dimethylphenylcarbamate)

    Science.gov (United States)

    2013-01-01

    Background At present, the study on the homogeneous-phase derivatization of cellulose in ionic liquid is mainly focused on its acetylation. To the best of our knowledge, there has been no such report on the preparation of cellulose-tris(3,5-dimethylphenylcarbamate) (CDMPC) with ionic liquid 1-allyl-3-methyl-imidazolium chloride (AmimCl) so far. Results With ionic liquid 1-allyl-3-methylimidazolium chloride (AmimCl) as a reaction solvent, cellulose-tris(3,5-dimethylphenylcarbamate) (CDMPC) was synthesized by the reaction of 3,5-dimethylphenyl isocyanate and soluble microcrystalline cellulose in a homogeneous phase. The synthesized CDMPC was then coated onto the surfaces of aminopropyl silica gel to prepare a chiral stationary phase (CSP). The prepared CSP was successfully used in chiral separation of seven racemic pesticides by high performance liquid chromatography (HPLC). Good chiral separation was obtained using n-hexane and different modifiers as the mobile phases under the optimal percentage and column temperature, with the resolution of metalaxyl, diniconazole, flutriafol, paclobutrazol, hexaconazole, myclobutanil and hexythiazox of 1.73, 1.56, 1.26, 1.00, 1.18, 1.14 and 1.51, respectively. The experimental results suggested it was a good choice using a green solvent of AmimCl for cellulose functionalization. Conclusion CDMPC was successfully synthesized as the chiral selector by reacting 3, 5-dimethylphenyl isocyanate with dissolved microcrystalline cellulose in a green ionic liquid of AmimCl. PMID:23890199

  18. Synthesis and Electrochemical Analysis of Algae Cellulose-Polypyrrole-Graphene Nanocomposite for Supercapacitor Electrode.

    Science.gov (United States)

    Aphale, Ashish; Chattopadhyay, Aheli; Mahakalakar, Kapil; Patra, Prabir

    2015-08-01

    A novel nanocomposite has been developed using extracted cellulose from marine algae coated with conductive polypyrrole and graphene nanoplateletes. The nanocomposite fabricated via in situ polymerization was used as an electrode for a supercapacitor device. The nanocomposite material has been electrochemically characterized using cyclic voltammetry to test its potential to super-capacitive behavior. The specific capacitance of polypyrrole-graphene-cellulose nanocomposite as calculated from cyclic voltammetry curve is 91.5 Fg-1 at the scan rate 50 mV s-1. Transmission electron microscope images show the polymerized polypyrrole -graphene coated cellulosic nanofibers. Scanning electron microscope images reveal an interesting "necklace" like beaded morphology on the cellulose fibers. It is observed that the necklace like structure start to disintegrate with the increase in graphene concentration. The open circuit voltage of the device with polypyrrole-graphene-cellulose electrode was found to be around 225 mV and that of the polypyrrole-cellulose device is only 53 mV without graphene. The results suggest marked improvement in the performance of the nanocomposite supercapacitor device upon graphene inclusion.

  19. Testing zinc chloride as a new catalyst for direct synthesis of cellulose di- and tri-acetate in a solvent free system under microwave irradiation.

    Science.gov (United States)

    El Nemr, Ahmed; Ragab, Safaa; El Sikaily, Amany

    2016-10-20

    This research demonstrates the effect of ZnCl2 as a catalyst on the esterification of commercial cotton cellulose using acetic anhydride in order to obtain di- and tri-cellulose acetates under microwave irradiation. It was discovered that microwave irradiation significantly increased the yield and reduced the reaction time. It was found that the maximum yield for cellulose triacetates was 95.83% under the reaction conditions that were as follows: 3min reaction time, 200mg of ZnCl2 catalyst and 20ml of Ac2O for 5g cellulose. However, the cellulose acetate obtained in this manner had the highest DS (2.87). The cellulose di-acetate was produced with the maximum yield of 89.97% and with the highest DS (2.69) using 25ml Ac2O, 200mg of ZnCl2 for 5g cellulose and in 3min reaction time. The effect of some factors such as the amount of used catalyst, the quantity of acetic acid anhydride and the reaction time of the esterification process have been investigated. The production of di- and tri-cellulose acetate and the degree of substitution were confirmed using Fourier-transform infrared (FTIR) and nuclear magnetic resonance (NMR). The thermal stability was investigated using thermo gravimetric analysis (TGA), differential thermal analysis (DTA) and differential scanning calorimetry (DSC). The molecular weight and the degree of polymerization were obtained using Gel Permeation Chromatography (GPC). The analysis confirmed the successful synthesis of di- and tri-cellulose acetate without degradation during the reaction; these results were found to be in contrast to some recent studies. The present study reveals that ZnCl2 is a new catalyst; it is effective as well as inexpensive and is a low toxicity catalyst for usage in cellulose esterification.

  20. Design, synthesis, α-glucosidase inhibitory activity, molecular docking and QSAR studies of benzimidazole derivatives

    Science.gov (United States)

    Dinparast, Leila; Valizadeh, Hassan; Bahadori, Mir Babak; Soltani, Somaieh; Asghari, Behvar; Rashidi, Mohammad-Reza

    2016-06-01

    In this study the green, one-pot, solvent-free and selective synthesis of benzimidazole derivatives is reported. The reactions were catalyzed by ZnO/MgO containing ZnO nanoparticles as a highly effective, non-toxic and environmentally friendly catalyst. The structure of synthesized benzimidazoles was characterized using spectroscopic technics (FT-IR, 1HNMR, 13CNMR). Synthesized compounds were evaluated for their α-glucosidase inhibitory potential. Compounds 3c, 3e, 3l and 4n were potent inhibitors with IC50 values ranging from 60.7 to 168.4 μM. In silico studies were performed to explore the binding modes and interactions between enzyme and synthesized benzimidazoles. Developed linear QSAR model based on density and molecular weight could predict bioactivity of newly synthesized compounds well. Molecular docking studies revealed the availability of some hydrophobic interactions. In addition, the bioactivity of most potent compounds had good correlation with estimated free energy of binding (ΔGbinding) which was calculated according to docked best conformations.

  1. Synthesis and characterization of cellulose derivatives obtained from bacterial cellulose; Sintese e caracterizacao de derivados celulosicos obtidos a partir da celulose bacteriana

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, Rafael L. de; Barud, Hernane; Ribeiro, Sidney J.L.; Messaddeq, Younes, E-mail: rafael.tu@gmail.com [Instituto de Quimica - Universidade Estadual Paulista Julio de Mesquita Filho - UNESP, Araraquara, SP (Brazil)

    2011-07-01

    The chemical modification of cellulose leads to production of derivatives with different properties from those observed for the original cellulose, for example, increased solubility in more traditional solvents. In this work we synthesized four derivatives of cellulose: microcrystalline cellulose, cellulose acetate, methylcellulose and carboxymethylcellulose using bacterial cellulose as a source. These were characterized in terms of chemical and structural changes by examining the degree of substitution (DS), infrared spectroscopy (FTIR) and nuclear magnetic resonance spectroscopy - NMR {sup 13}C. The molecular weight and degree of polymerization were evaluated by viscometry. The characterization of the morphology of materials and thermal properties were performed with the techniques of X-ray diffraction, electron microscopy images, differential scanning calorimetry (DSC) and thermogravimetric analysis. (author)

  2. Use of alginate, chitosan and cellulose nanocrystals as emulsion stabilizers in the synthesis of biodegradable polymeric nanoparticles.

    Science.gov (United States)

    Rescignano, Nicoletta; Fortunati, Elena; Armentano, Ilaria; Hernandez, Rebeca; Mijangos, Carmen; Pasquino, Rossana; Kenny, José Maria

    2015-05-01

    Biopolymeric nanoparticles (NPs) based on a biodegradable poly(DL-Lactide-co-Glycolide) PLGA copolymer matrix combined with alginate, chitosan and nanostructured cellulose crystals as three different natural emulsion stabilizers, were synthesized by a double emulsion (water/oil/water) method with subsequent solvent evaporation. The morphological, thermal, chemical and rheological properties of the novel designed NPs and the effect of the different emulsion stabilizers used during the synthesis were deeply investigated in order to optimize the synthesis procedure and the development of biodegradable nanoparticles coated with natural polymers. The morphological analysis of the produced nanoparticles showed that all the different formulations presented a spherical shape with smooth surface. Infrared spectroscopy investigations showed that the PLGA copolymer maintained its backbone structure and confirmed the presence of chitosan, alginate and cellulose nanocrystals (CNC) on the nanoparticle surface. The obtained results suggest that PLGA nanoparticles with CNC as emulsion stabilizer might represent promising formulations opening new perspective in the field of self-assembly of biodegradable nanomaterials for medical and pharmaceutical applications.

  3. First Synthesis of 3'- Geranyl-2', 3,4,4'-tetrahydroxychalcone with 5 α- Reductase Inhibitory Properties

    Institute of Scientific and Technical Information of China (English)

    LIU Hong-Xing; HUANG Chu-Sheng; CHEN Xi-Hui; ZHU Yan-Yun

    2003-01-01

    @@ The geranylated chalcone 1,3′-geranyl-2′, 3,4,4′-tetvahydroxychalcone with high 5α-reductase inhibitory prop erties, was isolated from Artocarpus incisus by Shimizu in 2000. [1] Herein, we describe the first synthesis of the natural product 1 by four steps starting from compounds 2 and 7. The synthetic route was shown in Scheme 1:

  4. SYNTHESIS AND CHARACTERIZATION OF CELLULOSE-GRAFT-POLY (L-LACTIDE VIA RING-OPENING POLYMERIZATION

    Directory of Open Access Journals (Sweden)

    Shu Xiao,

    2012-02-01

    Full Text Available Cellulose-graft-poly (L-lactide (cellulose-g-PLLA was prepared under homogeneous mild conditions. Ring-opening polymerization (ROP was carried out successfully using 4-dimethylaminopyridine (DMAP as an organic catalyst in an ionic liquid 1-allyl-3-methylimidazolium chloride (AmimCl. The structure of the polymer was characterized by GPC, 1H NMR, 13C NMR, FT-IR, TGA, WAXD, and AFM. The results indicated that the grafting rate of the polymer reached 4.44, which was higher than that reported in AmimCl with Sn(oct2 as a catalyst. In addition, AFM showed that the polymer in solution could aggregate and self-assemble into an approximately spherical structure, which was different from the rod-like structure of cellulose and round-like polylactic acid particles.

  5. Synthesis and characterization of cellulose acetate from rice husk: eco-friendly condition.

    Science.gov (United States)

    Das, Archana M; Ali, Abdul A; Hazarika, Manash P

    2014-11-04

    Cellulose acetate was synthesized from rice husk by using a simple, efficient, cost-effective and solvent-free method. Cellulose was isolated from rice husk (RH) using standard pretreatment method with dilute alkaline and acid solutions and bleaching with 2% H2O2. Cellulose acetate (CA) was synthesized successfully with the yield of 66% in presence of acetic anhydride and iodine as a catalyst in eco-friendly solvent-free conditions. The reaction parameters were standardized at 80 °C for 300 min and the optimum results were taken for further study. The extent of acetylation was evaluated from % yield and the degree of substitution (DS), which was determined by (1)H NMR and titrimetrically. The synthesized products were characterized with the help modern analytical techniques like FT-IR, (1)H NMR, XRD, etc. and the thermal behavior was evaluated by TGA and DSC thermograms. Copyright © 2014 Elsevier Ltd. All rights reserved.

  6. Synthesis of thermotropic cellulose derivatives and their behaviour as ion conducting materials

    CERN Document Server

    Yue, Z

    2002-01-01

    4-methoxy-4'- oxylbiphenyl group and 4-methoxyphenyl-4'-oxybenzoate group, were incorporated onto the cellulose backbone via a flexible spacer, respectively. The effects of the structure of the mesogenic groups and the length of spacer on the thermotropic liquid crystallinity of these polymers were investigated. Novel thermotropic cellulose derivatives containing poly(ethylene oxide) (PEO) side chains and pendant mesogenic side chains were synthesized and characterized. The PEO-350 groups were incorporated onto the cellulose backbone via ester or ether linkage, and the three products, including two highly substituted esters (COE-1 and HPCOE-1A) and a regioselective substituted ether (TPEOCELL), all exhibit thermotropic liquid crystallinity. Among them TPEOCELL forms a right-handed chiral nematic mesophase at room temperature, with the selective reflection in the wavelength of the visible range; the influence of salt on the cholesteric optical properties was examined. These three polymers were employed as poly...

  7. Synthesis and characterization of antibacterial carboxymethyl cellulose/ZnO nanocomposite hydrogels.

    Science.gov (United States)

    Yadollahi, Mehdi; Gholamali, Iman; Namazi, Hassan; Aghazadeh, Mohammad

    2015-03-01

    In this study, carboxymethyl cellulose/ZnO nanocomposite hydrogels have been synthesized through the in situ formation of ZnO nanoparticles within swollen carboxymethyl cellulose hydrogels. The formation of ZnO nanoparticles in the hydrogels was confirmed using X-ray diffraction, UV-vis spectroscopy and scanning electron microscopy (SEM) studies. SEM micrographs revealed the formation of ZnO nanoparticles with size range of 10-20 nm within the hydrogel matrix. The prepared nanocomposite hydrogels showed a pH and salt sensitive swelling behavior. The ZnO nanocomposite hydrogels have rather higher swelling in different aqueous solutions in comparison with neat hydrogel. The nanocomposite hydrogels demonstrated antibacterial effects against Escherichia coli and Staphylococcus aureus bacteria. The developed carboxymethyl cellulose/ZnO nanocomposite hydrogels can be used effectively for biomedical application.

  8. Synthesis and Characterization of Cellulose from Green Bamboo by Chemical Treatment with Mechanical Process

    Directory of Open Access Journals (Sweden)

    Fui Kiew Liew

    2015-01-01

    Full Text Available Bamboo cellulose was prepared by chemical process involving dewaxing, delignification, and mercerization process. Four samples namely, green bamboo fiber (GBF, dewaxed bamboo fiber (DBF, delignified bamboo fiber (DLBF, and cellulose fiber (CF had been analysed. FTIR and TGA analysis confirmed the removal of hemicellulose and lignin at the end stage of the process. FTIR results reveal that the D-cellulose OH group occurred at 1639 cm−1 region. SEM micrograph showed that mercerization leads to fibrillation and breakage of the fiber into smaller pieces which promote the effective surface area available for contact. Barrer, Joiyner, and Halenda (BJH method confirmed that the effective surface area of CF is two times larger compared to GBF. CF showed the highest activation energy compared to GBF. It indicates that CF was thermally stable.

  9. Microwave-assisted combustion synthesis of nano iron oxide/iron-coated activated carbon, anthracite, cellulose fiber, and silica, with arsenic adsorption studies

    Science.gov (United States)

    Combustion synthesis of iron oxide/iron coated carbons such as activated carbon, anthracite, cellulose fiber and silica is described. The reactions were carried out in alumina crucibles using a Panasonic kitchen microwave with inverter technology, and the reaction process was com...

  10. SYNTHESIS OF THERMALLY STABLE CARBOXYMETHYL CELLULOSE/METAL BIODEGRADABLE NANOCOMPOSITES FOR POTENTIAL BIOLOGICAL APPLICATIONS

    Science.gov (United States)

    A green approach is described that generates bulk quantities of nanocomposites containing transition metals such as Cu, Ag, In and Fe at room temperature using a biodegradable polymer carboxymethyl cellulose (CMC) by reacting respective metal salts with sodium salt of CMC in aqu...

  11. Green synthesis of bacterial cellulose via acetic acid pre-hydrolysis liquor of agricultural corn stalk used as carbon source.

    Science.gov (United States)

    Cheng, Zheng; Yang, Rendang; Liu, Xu; Liu, Xiao; Chen, Hua

    2017-06-01

    Herein, bacterial cellulose (BC) was synthesized by acetobacter xylinum via organic acid pre-hydrolysis liquor of agricultural corn stalk used as carbon source. Acetic acid was applied to pretreat the corn stalk, then, the prehydrolysate was detoxified by sequential steps of activated carbon and ion exchange resin treatment prior to use as carbon source to cultivate acetobacter xylinum. Moreover, the recovery of acetic acid was achieved for facilitating the reduction of cost. The results revealed that the combination method of detoxification treatment was very effective for synthesis of BC, yield could be up to 2.86g/L. SEM analysis showed that the diameter size of BC between 20 and 70mm. In summary, the process that bacterial cellulose was biosynthesized via prehydrolysate from agricultural corn stalk used as carbon source is feasible, and the ability to recover organic acid make it economical, sustainable and green, which fits well into the biorefinery concept. Copyright © 2017 Elsevier Ltd. All rights reserved.

  12. A practical synthesis of sarpogrelate hydrochloride and in vitro platelet aggregation inhibitory activities of its analogues

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    A convenient approach for the preparation of sarpogrelate hydrochloride was developed.Two series of sarpogrelate hydrochloride analogues were designed and synthesized in order to improve their platelet aggregation inhibitory activities, biological tests suggested that these compounds have platelet aggregation inhibitory activities to some extent.

  13. Synthesis of mangiferin derivates and study their potent PTP1B inhibitory activity

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Protein tyrosine phosphatase 1B (PTP1B) has received considerable attention from the drug industry as a potential treatment fordiabetes mellitus. Mangiferin has been reported to possess significant antidiabetic activity. Based on the previous study, eight new mangiferin derivates were synthesized and evaluated for their PTP1B inhibitory activity. Some of them displayed good inhibitory activity on PTP1B.

  14. Microwave-assisted synthesis and tyrosinase inhibitory activity of chalcone derivatives.

    Science.gov (United States)

    Liu, Jinbing; Chen, Changhong; Wu, Fengyan; Zhao, Liangzhong

    2013-07-01

    A series of chalcones and their derivatives were synthesized, and their inhibitory effects on the diphenolase activity of mushroom tyrosinase were evaluated. The results showed that some of the synthesized compounds exhibited significant inhibitory activity, and four compounds exhibited more potent tyrosinase inhibitory activity than the reference standard inhibitor kojic acid (5-hydroxy-2-(hydroxymethyl)-4H-pyran-4-one). Specifically, 1-(-1-(4-methoxyphen- yl)-3-phenylallylidene)thiosemicarbazide (18) exhibited the most potent tyrosinase inhibitory activity with IC₅₀ value of 0.274 μM. The inhibition mechanism analysis of 1-(-1-(2,4-dihydroxyphenyl)-3-phenylallylidene) thiosemicarbazide (16) and 1-(-1-(4-methoxyphenyl)-3-phenylallylidene) thiosemicarbazide (18) demonstrated that the inhibitory effects of the two compounds on the tyrosinase were irreversible. Preliminary structure activity relationships' analysis suggested that further development of such compounds might be of interest.

  15. Synthesis of amide-functionalized cellulose esters by olefin cross-metathesis.

    Science.gov (United States)

    Meng, Xiangtao; Edgar, Kevin J

    2015-11-05

    Cellulose esters with amide functionalities were synthesized by cross-metathesis (CM) reaction of terminally olefinic esters with different acrylamides, catalyzed by Hoveyda-Grubbs 2nd generation catalyst. Chelation by amides of the catalyst ruthenium center caused low conversions using conventional solvents. The effects of both solvent and structure of acrylamide on reaction conversion were investigated. While the inherent tendency of acrylamides to chelate Ru is governed by the acrylamide N-substituents, employing acetic acid as a solvent significantly improved the conversion of certain acrylamides, from 50% to up to 99%. Homogeneous hydrogenation using p-toluenesulfonyl hydrazide successfully eliminated the α,β-unsaturation of the CM products to give stable amide-functionalized cellulose esters. The amide-functionalized product showed higher Tg than its starting terminally olefinic counterpart, which may have resulted from strong hydrogen bonding interactions of the amide functional groups.

  16. Silver/chitosan/cellulose fibers foam composites: from synthesis to antibacterial properties.

    Science.gov (United States)

    Guibal, Eric; Cambe, Simon; Bayle, Sandrine; Taulemesse, Jean-Marie; Vincent, Thierry

    2013-03-01

    Chitosan, associated with cellulose fibers, can be used for elaborating sponge-like structures (membranes, foams) for the binding of silver ions. The composite material has very promising antibacterial properties versus Pseudomonas aeruginosa (Gram(-))≫Escherichia coli (Gram(-))>Staphylococcus hominis (Gram(+))≫Staphylococcus aureus (Gram(+)). The amount of silver required for bactericidal effect is quite low (below 0.1 mg per disk, this means less than 6 mg Ag g(-1)) in antibiogram-type test but also for the treatment of water suspensions (in dynamic mode with water recycling). The presence of cellulose fibers improves the efficiency of metal binding, due to chitosan dispersion and enhancement of the availability and accessibility of amine groups. Silver nanoparticles (about 100 nm) were observed by scanning electron microscopy. The photo-reduction (exposure to sun light or UV lamp) leaded to the partial aggregation of silver nanoparticles: metal ions that were released tended to aggregate at the surface of the material.

  17. Synthesis of a microhydrogel composite from cellulose nanowhiskers and starch for drug delivery.

    Science.gov (United States)

    Mauricio, Marcos R; da Costa, Pablo G; Haraguchi, Shirani K; Guilherme, Marcos R; Muniz, Edvani C; Rubira, Adley F

    2015-01-22

    This work describes the preparation of a microhydrogel composite from cellulose nanowhiskers (CNW) and starch in an ultrasound assisted-emulsion. CNW, which showed rod-like morphology, was obtained by acid hydrolysis of cane-based cellulose. The introduction of vinyl bonds to both CNW and starch enabled us to create the microhydrogel composite in which CNW played a role as a covalent cross-linker. Furthermore, CNW may act as an emulsifying agent for emulsion, improving both sphericity and homogeneity of the microparticles. The drug release was regulated in response to changes in the CNW amounts. The modeling of the release kinetics indicated that the drug release is driven by an anomalous mechanism and that the addition of CNW to starch microparticles led to differences in that mechanism. The release rate became ca. 2.9 times slower when CNW is added. When combined with starch, CNW played a role as a retardant factor for drug release.

  18. One-pot synthesis of levulinic acid from cellulose in ionic liquids.

    Science.gov (United States)

    Shen, Yue; Sun, Jian-Kui; Yi, Yu-Xuan; Wang, Bo; Xu, Feng; Sun, Run-Cang

    2015-09-01

    A simple and effective route for the production of levulinic acid (LA) from cellulose has been developed in SO3H-functionalized ionic liquids. The effects of ionic liquid structures, reaction conditions and combination of metal chlorides with ILs on the yield of LA were investigated, where the highest yield of 39.4% was obtained for 120 min in the presence of 1-(4-sulfonic acid) butyl-3-methylimidazolium hydrogen sulphate ([BSMim]HSO4) with addition of H2O. The catalytic activities of ionic liquids depended on the anions and decreased in the order: CF3SO3(-)>HSO4(-) > OAc(-), which was in good agreement with their acidity order. The ILs play a dual solvent-acid role for the cellulose conversion into LA and exhibited favorable catalytic activity over four repeated runs.

  19. Synthesis Magnesium Hydroxide Nanoparticles and Cellulose Acetate- Mg(OH2-MWCNT Nanocomposite

    Directory of Open Access Journals (Sweden)

    M. Ghorbanali

    2015-04-01

    Full Text Available Mg(OH2 nanoparticles were synthesized by a rapid microwave reaction. The effect of sodium dodecyl sulfonate (SDS as anionic surfactant and cetyl tri-methyl ammonium bromide (CTAB as cationic surfactant on the morphology of magnesium hydroxide nanostructures was investigated. Multi wall carbon nano tubes was organo-modified for better dispersion in cellulose acetate matrix. The influence of Mg(OH2 nanoparticles and modified multi wall carbon nano tubes (MWCNT on the thermal stability of the cellulose acetate (CA matrix was studied using thermo-gravimetric analysis (TGA. Nanostructures were characterized by X-ray diffraction (XRD, scanning electron microscopy (SEM and Fourier transform infrared (FT-IR spectroscopy. Thermal decomposition of the nanocomposites shift towards higher temperature in the presence of Mg(OH2 nanostructures. The enhancement of thermal stability of nanocomposites is due to the endothermic decomposition of Mg(OH2 and release of water which dilutes combustible gases.

  20. Synthesis of CMC from Palm Midrib Cellulose as Stabilizer and Thickening Agent in Food

    Directory of Open Access Journals (Sweden)

    Firman Sebayang

    2017-02-01

    Full Text Available The using of carboxymethyl cellulose (CMC from palm midrib as stabilizer on ice-cream making is done in three steps. First step is isolation process of α-cellulose from palm midrib powder, FTIR analysis shows that the compound is a cellulose molecule. The second step is alkalization with isopropanol as the solvent, carboxymethylation with monochloroacetic acid, and neutralization with CH3COOH 90% then ethanol, methanol and aquadest are used for purification followed with centrifugation process and adding in acetone which gives carboxymethyl cellulose a positive result in qualitative analysis. FTIR peak obtained is similar to that of commercial CMC, with the degree of substitution 0.82 and viscosity 0.076 ml/g. The last step is ice cream making process. In this step, CMC is added into the ice-cream batter with variated concentration of CMC starting from 0 to 0.5%. Ice-cream produced is then given melting time test and the overrun value is determined. Based on the research, 0.5% addition of CMC shows the most optimum melting time which is 31.02 minutes and overrun value of 42.34%. Organoleptic test given to 15 respondents also show that ice-cream with addition of 0.5% CMC gives the best result for the soft texture, sweet taste, fragrance aroma and light brown colour. CMC for thickening agent in syrup is measured with Ostwald viscometer. It shows that syrup is thicker with the addition of CMC. The highest vitamin-C content in passion fruit syrup is in addition of 0.3% which is 330.20.

  1. Chelators influenced synthesis of chitosan-carboxymethyl cellulose microparticles for controlled drug delivery

    Science.gov (United States)

    Samrot, Antony V.; Akanksha; Jahnavi, Tatipamula; Padmanaban, S.; Philip, Sheryl-Ann; Burman, Ujjala; Rabel, Arul Maximus

    2016-07-01

    In this study, polyphenolic curcumin is entrapped within microcomposites made of biopolymers chitosan (CS) and carboxymethyl cellulose (CMC) formulated by ionic gelation method. Here, different concentrations of two chelating agents, barium chloride and sodium tripolyphosphate, are used to make microcomposites. Thus, the synthesized microparticles were characterized by FTIR, and their surface morphology was studied by SEM. Drug encapsulation efficiency and the drug release kinetics of CS-CMC composites are also studied. The produced microcomposites were used to study antibacterial activity in vitro.

  2. Chelators influenced synthesis of chitosan-carboxymethyl cellulose microparticles for controlled drug delivery

    Science.gov (United States)

    Samrot, Antony V.; Akanksha; Jahnavi, Tatipamula; Padmanaban, S.; Philip, Sheryl-Ann; Burman, Ujjala; Rabel, Arul Maximus

    2016-11-01

    In this study, polyphenolic curcumin is entrapped within microcomposites made of biopolymers chitosan (CS) and carboxymethyl cellulose (CMC) formulated by ionic gelation method. Here, different concentrations of two chelating agents, barium chloride and sodium tripolyphosphate, are used to make microcomposites. Thus, the synthesized microparticles were characterized by FTIR, and their surface morphology was studied by SEM. Drug encapsulation efficiency and the drug release kinetics of CS-CMC composites are also studied. The produced microcomposites were used to study antibacterial activity in vitro.

  3. Biochemical localization of a protein involved in Gluconacetobacter hansenii cellulose synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Iyer, Prashanti R; Catchmark, Jeffrey M; Brown, Nicole Robitaille; Tien, Ming

    2011-02-08

    Using subcellular fractionation and Western blot methods, we have shown that AcsD, one of the proteins encoded by the Acetobacter cellulose synthase (acs) operon, is localized in the periplasmic region of the cell. AcsD protein was heterologously expressed in Escherichia coli and purified using histidine tag affinity methods. The purified protein was used to obtain rabbit polyclonal antibodies. The purity of the subcellular fractions was assessed by marker enzyme assays.

  4. Synthesis and characterization of hydrogels from cellulose acetate by esterification crosslinking with EDTA dianhydride.

    Science.gov (United States)

    Senna, André M; Novack, Kátia Monteiro; Botaro, Vagner R

    2014-12-19

    Hydrogels were prepared from cellulose acetate with a degree substitution (DS) 2.5 dissolved in dimethylformamide by esterification crosslinking with Ethylenediaminetetraacetic dianhydride (EDTAD) catalyzed by triethylamine. Subsequent conversion of the unreacted carboxyl groups to sodium carboxylates by the addition of aqueous NaHCO3 was performed to enhance the water affinity of the gels. The absorbency of the products was strongly dependent on the amount of EDTAD that was esterified to cellulose acetate, and the highest absorbency was observed for the hydrogel composed of approximately 0.36 molecules of EDTAD per repeat unit of cellulose acetate. The hydrogels were synthesized with different degrees of crosslinking and were analyzed by IR spectral (FTIR), near infrared (NIR), thermogravimetry analysis (TG and DTG), and crosslink density evaluation by Flory-Rehner theory. The hydrogels have synthesized with molar ratios EDTAD/OH groups: [1/1], [1/2], and [0.1/1]. The capacity for water absorbency was studied and compared with the water absorbency of the CA.

  5. Rigid polyurethane foam reinforced with cellulose whiskers:Synthesis and characterization

    Institute of Scientific and Technical Information of China (English)

    Yang Li; Hongfeng Ren; Arthur J Ragauskas

    2010-01-01

    A novel nanocomposite of rigid polyurethane foam was prepared by the polymerization of a sucrose-based polyol, a glycerol-based polyol and polymeric methylene diphenyl diisocyanate in the presence of cellulose whiskers. The cell morphology of the resulting foams was examined by scanning electron microscopy which showed both the pure foam and the nanocomposite foam had homogeneous cell dispersion and uniform cell size of approximately 200μm. Analysis of the foams by Fourier transform infrared (FT-IR) spectroscopy indicated that both samples exhibited signals attributed to the polyurethane including the NH stretching and bending vibrations at 3320 cm-1 and 1530 cm-1, the OC=O vibration at 1730 cm-1 and the CO-NH vibration at 1600 cm-1. FT-IR analysis of the nanocomposite indicated that cellulose whiskers were crosslinked with the polyurethane matrix as the signal intensity of the OH stretch at 3500 cm-1 was significantly reduced in comparison to the spectral data acquired for a control sample prepared from the pure polyurethane foam mixed with cellulose whiskers. According to ASTM standard testing procedures, the tensile modulus, tensile strength and yield strength of the nanocomposite foam were found to be improved by 36.8%, 13.8%and 15.2%, and the compressive modulus and strength were enhanced by 179.9% and 143.4%, respectively. Dynamic mechanical analysis results testified the improvements of mechanical properties and showed a better thermal stability of the nanocomposite foam.

  6. Synthesis of novel aminated cellulose microsphere adsorbent for efficient Cr(VI) removal

    Science.gov (United States)

    Yu, Tianlin; Liu, Siqi; Xu, Min; Peng, Jing; Li, Jiuqiang; Zhai, Maolin

    2016-08-01

    A novel aminated cellulose microsphere adsorbent (CVN) was successfully prepared by radiation-induced graft polymerization of vinylbenzyl chloride (VBC) onto cellulose microsphere (CMS), followed by amination. Micro-FTIR, XPS and SEM confirmed the structure of CVN. The adsorption behavior of Cr(VI) onto CVN from solution was well fitted by the pseudo-second order kinetic model. The isothermal adsorption of Cr(VI) was observed at pH 4.68 with adsorption capacity of 129 mg/g in accordance with Langmuir thermal model, and the removal of Cr(VI) from solution could be 91% at a low amount (20 mg) of adsorbent. The best pH for adsorption of Cr(VI) was nearly 3.08, and with the increasing of temperature, the adsorption capacity of Cr(VI) increased. XPS analysis confirmed the adsorption mechanism of Cr(VI) was ion-exchange mechanism, while common co-ions such as Na+, Mg2+, Cu2+, Ca2+, Zn2+, Ni2+, Cl-, NO3- has no significant effect on the adsorption capacity of Cr(VI), and the Cr(VI) removal of 80% still could be obtained compared with that of fresh CVN adsorbent. Finally, spent CVN could be regenerated under 2 mol/L NaCl. The work indicated that aminated cellulose adsorbent could be prepared successfully by radiation-induced grafting and amination and CVN is a promising bio-adsorbent in the removing Cr(VI) from waste water.

  7. Synthesis and Characterization of Methyl Cellulose/Keratin Hydrolysate Composite Membranes

    Directory of Open Access Journals (Sweden)

    Bernd M. Liebeck

    2017-03-01

    Full Text Available It is known that aqueous keratin hydrolysate solutions can be produced from feathers using superheated water as solvent. This method is optimized in this study by varying the time and temperature of the heat treatment in order to obtain a high solute content in the solution. With the dissolved polypeptides, films are produced using methyl cellulose as supporting material. Thereby, novel composite membranes are produced from bio-waste. It is expected that these materials exhibit both protein and polysaccharide properties. The influence of the embedded keratin hydrolysates on the methyl cellulose structure is investigated using Fourier transform infrared spectroscopy (FTIR and wide angle X-ray diffraction (WAXD. Adsorption peaks of both components are present in the spectra of the membranes, while the X-ray analysis shows that the polypeptides are incorporated into the semi-crystalline methyl cellulose structure. This behavior significantly influences the mechanical properties of the composite films as is shown by tensile tests. Since further processing steps, e.g., crosslinking, may involve a heat treatment, thermogravimetric analysis (TGA is applied to obtain information on the thermal stability of the composite materials.

  8. Leukemia inhibitory factor antagonizes gonadotropin induced-testosterone synthesis in cultured porcine leydig cells: sites of action.

    Science.gov (United States)

    Mauduit, C; Goddard, I; Besset, V; Tabone, E; Rey, C; Gasnier, F; Dacheux, F; Benahmed, M

    2001-06-01

    In the present report, the action of leukemia inhibitory factor (LIF) on testicular steroid hormone formation was studied. For this purpose, the direct effects of LIF were evaluated on basal and human (h)CG-stimulated testosterone synthesis by cultured, purified Leydig cells isolated from porcine testes. LIF reduced (more than 60%) hCG-stimulated testosterone synthesis. This inhibitory effect was exerted in a dose- and time-dependent manner. The maximal and half-maximal effects were obtained with, respectively, 10 ng/ml (0.5 nM ) and 2.5 ng/ml (0.125 nM ) of LIF after a 48-h treatment of the Leydig cells. Such an effect of the cytokine was not a cytotoxic effect, because it was reversible and Leydig cells recovered most of their steroidogenic activity after the removal of LIF. Considering the sites of action of LIF in inhibiting gonadotropin-stimulated testosterone formation, it was shown that LIF significantly (P observation indicates that the antigonadotropic action of the cytokine is exerted in a predominant manner at a step (or steps) located beyond cAMP formation. Furthermore, incubation of Leydig cells with 22R-hydroxycholesterol (5 microg/ml, 2 h), a cholesterol substrate derivative that does not need an assisted process to be delivered to the inner mitochondrial membrane, reversed most of the inhibitory effect of LIF on the steroid hormone formation. Such results indicate that LIF acts by reducing cholesterol substrate availability in the mitochondria. Consequently, LIF action was tested on steroidogenic acute regulatory protein and PBR (peripheral benzodiazepine receptor) shown to be potentially involved in such a cholesterol transfer. LIF reduced, in a dose- and time-dependent manner, LH/hCG-induced steroidogenic acute regulatory protein messenger RNA levels. The maximal inhibitory effect was obtained with 6.6 ng/ml of LIF after 48 h of treatment. In contrast, LIF had no effect on PBR messenger RNA expression or PBR binding. This inhibitory effect of LIF

  9. Synthesis of 2-Heterocyclomethyl-5-diphenylmethylenecyclopentanone Hydrochlorides and their Inhibitory Effect on Tumor Cell Growth

    Institute of Scientific and Technical Information of China (English)

    Yun Hai ZHANG; Lin Xiang ZHAO; Zhen Jun BIAN; Rui WANG; Fu Yuan SUN

    2006-01-01

    Sixteen new 2-heterocyclomethyl-5-diphenylmethylenecyclopentanone hydrochlorides were designed and synthesized. The growth inhibitory effect of these compounds in vitro was conducted using a MTT assay in human breast cancer T47D cells.

  10. Mannosylated N-aryl substituted 3-hydroxypyridine-4-ones: synthesis, hemagglutination inhibitory properties, and molecular modeling.

    Science.gov (United States)

    Car, Zeljka; Hrenar, Tomica; Petrović Peroković, Vesna; Ribić, Rosana; Seničar, Mateja; Tomić, Srđanka

    2014-10-01

    Structural alterations of the aglycon portions of α-mannosides influence their inhibitory potency toward type 1-fimbriated Escherichia coli. The aim of our work was to prepare and explore inhibitory properties of novel mannosylated N-aryl-substituted 3-hydroxypyridine-4-ones because they possess needed structural characteristics as possible FimH antagonists. Hemagglutination inhibitory tests showed that the examined 3-hydroxypyridine-4-one α-mannosides exhibited better inhibitory activity than methyl α-d-mannopyranoside used as a reference compound. Molecular modeling studies revealed the specific interactions responsible for the observed binding activities toward the mannose-specific FimH lectin. The activity depends on the substituent in p-position on the aglycon aromatic ring. © 2014 John Wiley & Sons A/S.

  11. Synthesis and VEGF inhibitory activity of 16,17-pyrazo-annulated steroids

    Institute of Scientific and Technical Information of China (English)

    Hong Shan Liu; Hu Ling Zheng; Mei Ge; Peng Xia; Ying Chen

    2011-01-01

    Eight 16,17-pyrazo-annulated steroidal derivatives were synthesized and evaluated in vitro vascular endothelial growth factor (VEGF) inhibitory activity with 2-methoxyestradiol (2-ME) as the reference compound. Most of the compounds showed potent VEGF inhibitory activity with EC50 values of micromolar or submicromolar range. Among them, the compounds 3 and 8 exhibited similar EC50 values and obviously better TI values compared with 2-ME.

  12. Cellulose acetate-directed growth of bamboo-raft-like single-crystalline selenium superstructures: high-yield synthesis, characterization, and formation mechanism.

    Science.gov (United States)

    Song, Ji-Ming; Zhan, Yong-Jie; Xu, An-Wu; Yu, Shu-Hong

    2007-06-19

    High-yield synthesis of bamboo-raft-like single-crystalline selenium superstructures has been realized for the first time via a facile solvothermal approach by reducing SeO2 with ethylene alcohol in the presence of cellulose acetate. The formation of a raftlike superstructure with various forms is strongly dependent on the temperature, amount of cellulose acetate, reaction time, and even preheating treatment. The suitable amount of cellulose acetate is essential for the formation of elegant and uniform raft Se. The morphology, microstructure, optical properties, and chemical compositions of bamboo-raft-like selenium were characterized using various techniques (X-ray diffraction, field emission scanning electron microscopy, transmission electron microscopy (TEM), high-resolution (HR) TEM, X-ray photoelectron spectroscopy, UV-vis spectroscopy, FTIR spectroscopy, and Raman spectroscopy). A possible growth mechanism has been proposed. Such special superstructures could provide a useful precursor for potential applications.

  13. Synthesis and Characterization of Metallic Gel Complexes Derived from Carboxymethyl Cellulose

    Directory of Open Access Journals (Sweden)

    H. D. Juneja

    2013-01-01

    Full Text Available The oxaloyl carboxymethyl cellulose (OCMC complexes of Mn(II, Co(II, Ni(II, Cu(II, and Zn(II metal ions have been synthesized and the coordination of OCMC in these complexes has been investigated through IR spectra, reflectance spectra, and thermal analysis. On the basis of spectral and thermal data an octahedral geometry was assigned to [Mn(IIOCMC(H2O2]n and [Co(IIOCMC(H2O2]n, square planar geometry was assigned to [Cu(IIOCMC]n, and tetrahedral geometry was assigned to [Ni(IIOCMC]n and [Zn(IIOCMC]n Metallic Gel complexes.

  14. Chelators influenced synthesis of chitosan–carboxymethyl cellulose microparticles for controlled drug delivery

    Directory of Open Access Journals (Sweden)

    Antony V. Samrot

    2016-07-01

    Full Text Available Abstract In this study, polyphenolic curcumin is entrapped within microcomposites made of biopolymers chitosan (CS and carboxymethyl cellulose (CMC formulated by ionic gelation method. Here, different concentrations of two chelating agents, barium chloride and sodium tripolyphosphate, are used to make microcomposites. Thus, the synthesized microparticles were characterized by FTIR, and their surface morphology was studied by SEM. Drug encapsulation efficiency and the drug release kinetics of CS–CMC composites are also studied. The produced microcomposites were used to study antibacterial activity in vitro.

  15. Synthesis of CaCO3 crystals using hydroxypropylmethyl cellulose hydrogel as template

    Institute of Scientific and Technical Information of China (English)

    ZHAO Jin; LI YanJun; CHENG GuoXiang

    2007-01-01

    Calcium carbonate crystallization was performed in hydrogel of hydroxypropylmethyl cellulose (HPMC). Results showed that the polyhydroxy functionalities in HPMC gel network facilitated the nucleation of aragonite which was not found in experiment without HPMC hydrogel and in experiment using methylcellulose (MC) hydrogel as template. On the other hand,due to the unique assembly of the macromolecules in HPMC hydrogel network,which was different from other hydrogels used in some previous reports,particular crystal morphology,corncob-like CaCO3,was obtained for the first time.

  16. Hydrothermal Synthesis of Nickel Hydroxide Nanostructures and Flame Retardant Poly Vinyl Alcohol and Cellulose Acetate Nanocomposites

    Directory of Open Access Journals (Sweden)

    S. R. Yousefi

    2016-01-01

    Full Text Available Nickel hydroxide nanostructures were synthesized by a hydrothermal reaction. The effect of different precursors and surfactants on the morphology of nickel hydroxide nanostructures was investigated. Nanostructures were characterized by X-ray diffraction, energy dispersive X-ray spectroscopy, scanning electron microscopy and Fourier transform infrared  spectroscopy. The influence of Ni(OH2 nanostructures on the thermal stability and flame retardancy of the poly vinyl alcohol and cellulose acetate matrix was studied using UL-94 analysis. The enhancement of thermal stability and flame retardancy of nanocomposites is due to the endothermic decomposition of Ni(OH2 and release of water which dilutes combustible gases.

  17. The thanatos mutation in Arabidopsis thaliana cellulose synthase 3 (AtCesA3) has a dominant-negative effect on cellulose synthesis and plant growth.

    Science.gov (United States)

    Daras, Gerasimos; Rigas, Stamatis; Penning, Bryan; Milioni, Dimitra; McCann, Maureen C; Carpita, Nicholas C; Fasseas, Constantinos; Hatzopoulos, Polydefkis

    2009-01-01

    Genetic functional analyses of mutants in plant genes encoding cellulose synthases (CesAs) have suggested that cellulose deposition requires the activity of multiple CesA proteins. Here, a genetic screen has led to the identification of thanatos (than), a semi-dominant mutant of Arabidopsis thaliana with impaired growth of seedlings. Homozygous seedlings of than germinate and grow but do not survive. In contrast to other CesA mutants, heterozygous plants are dwarfed and display a radially swollen root phenotype. Cellulose content is reduced by approximately one-fifth in heterozygous and by two-fifths in homozygous plants, showing gene-dosage dependence. Map-based cloning revealed an amino acid substitution (P578S) in the catalytic domain of the AtCesA3 gene, indicating a critical role for this residue in the structure and function of the cellulose synthase complex. Ab initio analysis of the AtCesA3 subdomain flanking the conserved proline residue predicted that the amino acid substitution to serine alters protein secondary structure in the catalytic domain. Gene dosage-dependent expression of the AtCesA3 mutant gene in wild-type A. thaliana plants resulted in a than dominant-negative phenotype. We propose that the incorporation of a mis-folded CesA3 subunit into the cellulose synthase complex may stall or prevent the formation of functional rosette complexes.

  18. Novel green synthesis of gold nanoparticles using Citrullus lanatus rind and investigation of proteasome inhibitory activity, antibacterial, and antioxidant potential.

    Science.gov (United States)

    Patra, Jayanta Kumar; Baek, Kwang-Hyun

    2015-01-01

    Biological synthesis of nanoparticles using nontoxic, eco-friendly approaches is gaining importance owing to their fascinating biocompatibility and environmentally benign nature. This study describes the green synthesis approach for synthesis of gold nanoparticles (ANPs) using aqueous extract of the rind of watermelon as a fruit waste and evaluate its biopotential in terms of proteasome inhibitory activity, antibacterial, and antioxidant potential. The synthesized ANPs were characterized using UV-vis spectroscopy, scanning electron microscopy, X-ray diffraction, Fourier-transform infrared spectroscopy, and thermogravimetric analysis. The surface plasmon resonance spectra of ANPs were obtained at 560 nm. Scanning electron microscopy image revealed that particles had a spherical shape and have a size distribution of 20-140 nm, followed by the elemental analysis by energy-dispersive X-ray spectroscopy. X-ray diffraction analysis confirmed the crystallite nature of the ANPs and Fourier-transform infrared spectroscopy revealed the involvement of bioactive compounds from watermelon rind in the synthesis, capping, and stabilization of ANPs. ANPs exhibited potential antibacterial activity against five different foodborne pathogenic bacteria with diameter of inhibition zones ranged between 9.23 and 11.58 mm. They also displayed strong synergistic antibacterial activity together with kanamycin (11.93-21.08 mm inhibition zones) and rifampicin (10.32-24.84 mm inhibition zones). ANPs displayed strong antioxidant activity in terms of DPPH radical scavenging (24.69%), nitric oxide scavenging (25.62%), ABTS scavenging (29.42%), and reducing power. Significantly high proteasome inhibitory potential of the ANPs (28.16%) could be highly useful for cancer treatment and targeted cancer drug delivery. Overall, results highlight a potential low-cost green method of synthesizing ANPs from food waste materials. Significant biopotentials of synthesized ANPs could make it a potential

  19. Rice Brittle culm 6 encodes a dominant-negative form of CesA protein that perturbs cellulose synthesis in secondary cell walls.

    Science.gov (United States)

    Kotake, Toshihisa; Aohara, Tsutomu; Hirano, Ko; Sato, Ami; Kaneko, Yasuko; Tsumuraya, Yoichi; Takatsuji, Hiroshi; Kawasaki, Shinji

    2011-03-01

    The brittle culm (bc) mutants of Gramineae plants having brittle skeletal structures are valuable materials for studying secondary cell walls. In contrast to other recessive bc mutants, rice Bc6 is a semi-dominant bc mutant with easily breakable plant bodies. In this study, the Bc6 gene was cloned by positional cloning. Bc6 encodes a cellulose synthase catalytic subunit, OsCesA9, and has a missense mutation in its highly conserved region. In culms of the Bc6 mutant, the proportion of cellulose was reduced by 38%, while that of hemicellulose was increased by 34%. Introduction of the semi-dominant Bc6 mutant gene into wild-type rice significantly reduced the percentage of cellulose, causing brittle phenotypes. Transmission electron microscopy analysis revealed that Bc6 mutation reduced the cell wall thickness of sclerenchymal cells in culms. In rice expressing a reporter construct, BC6 promoter activity was detected in the culms, nodes, and flowers, and was localized primarily in xylem tissues. This expression pattern was highly similar to that of BC1, which encodes a COBRA-like protein involved in cellulose synthesis in secondary cell walls in rice. These results indicate that BC6 is a secondary cell wall-specific CesA that plays an important role in proper deposition of cellulose in the secondary cell walls.

  20. Enzymatic Synthesis of Oligo(ethylene glycol)-Bearing Cellulose Oligomers for in Situ Formation of Hydrogels with Crystalline Nanoribbon Network Structures.

    Science.gov (United States)

    Nohara, Takatoshi; Sawada, Toshiki; Tanaka, Hiroshi; Serizawa, Takeshi

    2016-11-29

    Enzymatic synthesis of cellulose and its derivatives has gained considerable attention for use in the production of artificial crystalline nanocelluloses with unique structural and functional properties. However, the poor colloidal stability of the nanocelluloses during enzymatic synthesis in aqueous solutions limits their crystallization-based self-assembly to greater architectures. In this study, oligo(ethylene glycol) (OEG)-bearing cellulose oligomers with different OEG chain lengths were systematically synthesized via cellodextrin phosphorylase-catalyzed oligomerization of α-d-glucose l-phosphate monomers against OEG-bearing β-d-glucose primers. The products were self-assembled into extremely well-grown crystalline nanoribbon network structures with the cellulose II allomorph, potentially due to OEG-derived colloidal stability of the nanoribbon's precursors, followed by the in situ formation of physically cross-linked hydrogels. The monomer conversions, average degree of polymerization, and morphologies of the nanoribbons changed significantly, depending on the OEG chain length. Taken together, our findings open a new avenue for the enzymatic reaction-based facile production of novel cellulosic soft materials with regular nanostructures.

  1. Synthesis, characterization and antibacterial activity of biodegradable starch/PVA composite films reinforced with cellulosic fibre.

    Science.gov (United States)

    Priya, Bhanu; Gupta, Vinod Kumar; Pathania, Deepak; Singha, Amar Singh

    2014-08-30

    Cellulosic fibres reinforced composite blend films of starch/poly(vinyl alcohol) (PVA) were prepared by using citric acid as plasticizer and glutaraldehyde as the cross-linker. The mechanical properties of cellulosic fibres reinforced composite blend were compared with starch/PVA crossed linked blend films. The increase in the tensile strength, elongation percentage, degree of swelling and biodegradability of blend films was evaluated as compared to starch/PVA crosslinked blend films. The value of different evaluated parameters such as citric acid, glutaraldehyde and reinforced fibre to starch/PVA (5:5) was found to be 25 wt.%, 0.100 wt.% and 20 wt.%, respectively. The blend films were characterized using Fourier transform-infrared spectrophotometry (FTIR), scanning electron microscopy (SEM) and thermogravimetric analysis (TGA/DTA/DTG). Scanning electron microscopy illustrated a good adhesion between starch/PVA blend and fibres. The blend films were also explored for antimicrobial activities against pathogenic bacteria like Staphylococcus aureus and Escherichia coli. The results confirmed that the blended films may be used as exceptional material for food packaging. Copyright © 2014 Elsevier Ltd. All rights reserved.

  2. Synthesis and characterization of carboxymethyl cellulose/layered double hydroxide nanocomposites

    Science.gov (United States)

    Yadollahi, Mehdi; Namazi, Hassan

    2013-04-01

    In this study, coprecipitation method was employed for intercalation of carboxy methyl cellulose (CMC) into hydrotalcite-like anionic clays (Mg/Al and Ni/Al). The synthesized nanocomposites were characterized using FTIR, XRD, TEM, and Thermo gravimetric analysis. Furthermore, their swelling behavior was studied at various pH values. The intercalation of Carboxymethyl cellulose polymeric chains into LDH sheets was confirmed by FTIR spectroscopy and XRD analysis. The d-values are 1.73 nm for the Mg-Al-CMC-LDH and 2.23 nm for the Ni-Al-CMC-LDH, supporting a multilayer arrangement of CMC into the LDH interlayer space. Thermo gravimetric analysis showed a better thermal resistance of CMC in the presence of LDH sheets, especially for Mg-Al-CMC-LDH. The obtained nanocomposites revealed a pH dependent swelling behavior. The swelling of the prepared nanocomposites increased slowly with increasing pH from 2 to 10. However, their swelling ratio increased sharply in the pH values above 10.

  3. Synthesis and characterization of carboxymethyl cellulose/layered double hydroxide nanocomposites

    Energy Technology Data Exchange (ETDEWEB)

    Yadollahi, Mehdi; Namazi, Hassan, E-mail: namazi@tabrizu.ac.ir [University of Tabriz, Research Laboratory of Dendrimers and Nanopolymers, Faculty of Chemistry (Iran, Islamic Republic of)

    2013-04-15

    In this study, coprecipitation method was employed for intercalation of carboxy methyl cellulose (CMC) into hydrotalcite-like anionic clays (Mg/Al and Ni/Al). The synthesized nanocomposites were characterized using FTIR, XRD, TEM, and Thermo gravimetric analysis. Furthermore, their swelling behavior was studied at various pH values. The intercalation of Carboxymethyl cellulose polymeric chains into LDH sheets was confirmed by FTIR spectroscopy and XRD analysis. The d-values are 1.73 nm for the Mg-Al-CMC-LDH and 2.23 nm for the Ni-Al-CMC-LDH, supporting a multilayer arrangement of CMC into the LDH interlayer space. Thermo gravimetric analysis showed a better thermal resistance of CMC in the presence of LDH sheets, especially for Mg-Al-CMC-LDH. The obtained nanocomposites revealed a pH dependent swelling behavior. The swelling of the prepared nanocomposites increased slowly with increasing pH from 2 to 10. However, their swelling ratio increased sharply in the pH values above 10.

  4. Efficient synthesis of chloro-derivatives of sialosyllactosylceramide, and their enhanced inhibitory effect on epidermal growth factor receptor activation.

    Science.gov (United States)

    Kawashima, Nagako; Qu, Huanhuan; Lobaton, Marlin; Zhu, Zhenyuan; Sollogoub, Matthieu; Cavenee, Webster K; Handa, Kazuko; Hakomori, Sen-Itiroh; Zhang, Yongmin

    2014-04-01

    Glycosphingolipids are components of essentially all mammalian cell membranes and are involved in a variety of significant cellular functions, including proliferation, adhesion, motility and differentiation. Sialosyllactosylceramide (GM3) is known to inhibit the activation of epidermal growth factor receptor (EGFR). In the present study, an efficient method for the total chemical synthesis of monochloro- and dichloro-derivatives of the sialosyl residue of GM3 was developed. The structures of the synthesized compounds were fully characterized by high-resolution mass spectrometry and nuclear magnetic resonance. In analyses of EGFR autophosphorylation and cell proliferation ([(3)H]-thymidine incorporation) in human epidermoid carcinoma A431 cells, two chloro-derivatives exhibited stronger inhibitory effects than GM3 on EGFR activity. Monochloro-GM3, but not GM3 or dichloro-GM3, showed a significant inhibitory effect on ΔEGFR, a splicing variant of EGFR that lacks exons 2-7 and is often found in human glioblastomas. The chemical synthesis of other GM3 derivatives using approaches similar to those described in the present study, has the potential to create more potent EGFR inhibitors to block cell growth or motility of a variety of types of cancer that express either wild-type EGFR or ΔEGFR.

  5. Design and Synthesis of Norendoxifen Analogues with Dual Aromatase Inhibitory and Estrogen Receptor Modulatory Activities

    Science.gov (United States)

    Lv, Wei; Liu, Jinzhong; Skaar, Todd C.; Flockhart, David A.; Cushman, Mark

    2015-01-01

    Both selective estrogen receptor modulators and aromatase inhibitors are widely used for the treatment of breast cancer. Compounds with both aromatase inhibitory and estrogen receptor modulatory activities could have special advantages for treatment of breast cancer. Our previous efforts led to the discovery of norendoxifen as the first compound with dual aromatase inhibitory and estrogen receptor binding activities. To optimize its efficacy and aromatase selectivity versus other cytochrome P450 enzymes, a series of structurally related norendoxifen analogues were designed and synthesized. The most potent compound, 4'-hydroxynorendoxifen (10), displayed elevated inhibitory potency against aromatase and enhanced affinity for estrogen receptors when compared to norendoxifen. The selectivity of 10 for aromatase versus other cytochrome P450 enzymes was also superior to norendoxifen. 4'-Hydroxynorendoxifen is therefore an interesting lead for further development to obtain new anticancer agents of potential value for the treatment of breast cancer. PMID:25751283

  6. Synthesis and study of nano-structured cellulose acetate based materials for energy applications; Synthese et etude de materiaux nanostructures a base d'acetate de cellulose pour applications energetiques

    Energy Technology Data Exchange (ETDEWEB)

    Fischer, F

    2006-12-15

    Nano-structured materials have unique properties (high exchange areas, containment effect) because of their very low characteristic dimensions. The elaboration way set up in this PhD work consists in applying the classical processes for the preparation of aerogel-like materials (combining sol-gel synthesis and CO{sub 2} supercritical extraction) to cellulosic polymers. This work is divided in four parts: a literature review, the presentation and the study of the chemical synthesis that leads to cellulose acetate-based aerogel, the characterizations (chemical, structural and thermal) of the elaborated nano-materials, and finally the study of the first carbons that were obtained after pyrolysis of the organic matrix. The formulations and the sol-gel protocol lead to chemical gels by crosslinking cellulose acetate using a poly-functional iso-cyanate. The dry materials obtained after solvent extraction with supercritical CO{sub 2} are nano-structured and mainly meso-porous. Correlations between chemical synthesis parameters (reagent concentrations, crosslinking rate and degree of polymerisation) and porous properties (density, porosity, pore size distribution) were highlighted thanks to structural characterizations. An ultra-porous reference aerogel, with a density equals to 0,245 g.cm{sup -3} together with a meso-porous volume of 3,40 cm{sup 3}.g{sup -1} was elaborated. Once in granular shape, this material has a thermal conductivity of 0,029 W.m{sup -1}.K{sup -1}. In addition, carbon materials produced after pyrolysis of the organic matrix and after grinding are nano-structured and nano-porous, even if important structural modifications have occurred during the carbonization process. The elaborated materials are evaluated for applications in relation with energy such as thermal insulation (organic aerogels) but also for energy conversion and storage through electrochemical way (carbon aerogels). (author)

  7. Microwave-Assisted Combustion Synthesis of Nano Iron Oxide/Iron-Coated Activated Carbon, Anthracite, Cellulose Fiber, and Silica, with Arsenic Adsorption Studies

    OpenAIRE

    2011-01-01

    Combustion synthesis of iron oxide/iron coated carbons such as activated carbon, anthracite, cellulose fiber, and silica is described. The reactions were carried out in alumina crucibles using a Panasonic kitchen microwave with inverter technology, and the reaction process was completed within a few minutes. The method used no additional fuel and nitrate, which is present in the precursor itself, to drive the reaction. The obtained samples were then characterized with X-ray mapping, scanning...

  8. Aqueous-Phase Synthesis of Silver Nanodiscs and Nanorods in Methyl Cellulose Matrix: Photophysical Study and Simulation of UV–Vis Extinction Spectra Using DDA Method

    OpenAIRE

    Sarkar Priyanka; Bhui Dipak Kumar; Bar Harekrishna; Sahoo Gobinda Prasad; Samanta Sadhan; Pyne Santanu; Misra Ajay

    2010-01-01

    Abstract We present a very simple and effective way for the synthesis of tunable coloured silver sols having different morphologies. The procedure is based on the seed-mediated growth approach where methyl cellulose (MC) has been used as soft-template in the growth solution. Nanostructures of varying morphologies as well as colour of the silver sols are controlled by altering the concentration of citrate in the growth solution. Similar to the polymers in the solution, citrate ions also dynami...

  9. Cellulose-Sulfuric Acid as an Efficient Biosupported Catalyst in One-Pot Synthesis of Novel Heteroaryl Substituted 1,4-Dihydropyridines

    Directory of Open Access Journals (Sweden)

    Manouchehr Mamaghani

    2013-01-01

    Full Text Available An efficient method for the synthesis of new heteroaryl substituted dihydropyridine derivatives via a one-pot four-component coupling reaction of heteroaldehyde, 1,3-diketone, ethylacetoacetate, and amonium acetate in the presence of cellulose-sulfuric acid as a biosupported solid acid catalyst was developed. The reaction gave the new derivatives of fused 1,4-dihydropyridines in lower reaction times and excellent yields (85–95%.

  10. Optimization of dicarboxylic acid cellulose synthesis: reaction stoichiometry and role of hypochlorite scavengers.

    Science.gov (United States)

    Sirviö, Juho Antti; Liimatainen, Henrikki; Visanko, Miikka; Niinimäki, Jouko

    2014-12-19

    The reaction conditions in terms of reaction time, sodium chlorite stoichiometry, and the effect of hypochlorite scavengers on the chlorite oxidation of dialdehyde cellulose (DAC) was studied. The impact of storage on the reactivity of DAC fibers was also investigated. It was found that chlorite oxidation of DAC is a rapid reaction, resulting in oxidation of 71% of the aldehyde after only 8 min when 2.5 times excess of sodium chlorite compared to aldehyde groups was used. Reactivity of DAC was observed to decrease quickly during the storage and only 68% of the aldehyde groups reacted after two weeks storage compared to the reaction performed with freshly prepared DAC. Hydrogen peroxide and sulfamic acid were observed to increase the reaction efficiency of chlorite oxidation by reducing the amount of side-reactions between chlorite and hypochlorite. A minor amount of sulfamic acid can be used to replace acetic acid as a catalyst. Copyright © 2014 Elsevier Ltd. All rights reserved.

  11. Synthesis of Polyaniline (PANI in Nano-Reaction Field of Cellulose Nanofiber (CNF, and Carbonization

    Directory of Open Access Journals (Sweden)

    Yuki Kaitsuka

    2016-02-01

    Full Text Available Polymerization of aniline in the presence of cellulose nano-fiber (CNF is carried out. We used dried CNF, CNF suspension, and CNF treated by enzyme and ultra-sonification to obtain polyaniline (PANI/CNF as a synthetic polymer/natural nano-polymer composite. The polymerization proceeds on the surface of CNF as a nano-reaction field. Resultant composites show extended effective π-conjugation length because CNF as a reaction field in molecular level produced polymer with expanded coil structure with an aid of orientation effect of CNF. Possibility of PANI β-pleats structure in molecular level of PANI on the CNF is also discussed. SEM observation showed that fine structure is easily obtained by combining PANI with CNF. Carbonization of PANI/CNF allows production of nano-fine form with shape preserved carbonization (SPC.

  12. Synthesis, characterization and antibacterial activity of cellulose acetate-tin (IV) phosphate nanocomposite.

    Science.gov (United States)

    Rathore, Bhim Singh; Sharma, Gaurav; Pathania, Deepak; Gupta, Vinod Kumar

    2014-03-15

    Cellulose acetate-tin (IV) phosphate nanocomposite (CA/TPNC) was prepared using simple method at 0-1 pH. The nanocomposite ion exchanger was characterized using some techniques such as Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), and thermogravimetric analysis (TGA/DTA/DSC). The nanocomposite material was explored for different properties such as ion exchange capacity, pH titration, elution behavior, thermal stability, and distribution coefficient. The ion exchange capacity of CA/TPNC was found higher compared to their inorganic counterpart. The distribution coefficient studies of nanocomposite ion exchanger were investigated for different metal ions. On the basis of distribution coefficient studies CA/TPNC material was found more selective for Cd(2+) and Mg(2+). CA/TPNC ion exchange was explored for antibacterial activities against E. coli bacteria.

  13. Novel green synthesis of gold nanoparticles using Citrullus lanatus rind and investigation of proteasome inhibitory activity, antibacterial, and antioxidant potential

    Directory of Open Access Journals (Sweden)

    Patra JK

    2015-12-01

    Full Text Available Jayanta Kumar Patra, Kwang-Hyun Baek School of Biotechnology, Yeungnam University, Gyeongsan, Gyeongbuk, Republic of Korea Abstract: Biological synthesis of nanoparticles using nontoxic, eco-friendly approaches is gaining importance owing to their fascinating biocompatibility and environmentally benign nature. This study describes the green synthesis approach for synthesis of gold nanoparticles (ANPs using aqueous extract of the rind of watermelon as a fruit waste and evaluate its biopotential in terms of proteasome inhibitory activity, antibacterial, and antioxidant potential. The synthesized ANPs were characterized using UV–vis spectroscopy, scanning electron microscopy, X-ray diffraction, Fourier-transform infrared spectroscopy, and thermogravimetric analysis. The surface plasmon resonance spectra of ANPs were obtained at 560 nm. Scanning electron microscopy image revealed that particles had a spherical shape and have a size distribution of 20–140 nm, followed by the elemental analysis by energy-dispersive X-ray spectroscopy. X-ray diffraction analysis confirmed the crystallite nature of the ANPs and Fourier-transform infrared spectroscopy revealed the involvement of bioactive compounds from watermelon rind in the synthesis, capping, and stabilization of ANPs. ANPs exhibited potential antibacterial activity against five different foodborne pathogenic bacteria with diameter of inhibition zones ranged between 9.23 and 11.58 mm. They also displayed strong synergistic antibacterial activity together with kanamycin (11.93–21.08 mm inhibition zones and rifampicin (10.32–24.84 mm inhibition zones. ANPs displayed strong antioxidant activity in terms of DPPH radical scavenging (24.69%, nitric oxide scavenging (25.62%, ABTS scavenging (29.42%, and reducing power. Significantly high proteasome inhibitory potential of the ANPs (28.16% could be highly useful for cancer treatment and targeted cancer drug delivery. Overall, results highlight a

  14. Synthesis of Benzofuran Derivatives via Rearrangement and Their Inhibitory Activity on Acetylcholinesterase

    Directory of Open Access Journals (Sweden)

    Ling-Yi Kong

    2010-11-01

    Full Text Available During a synthesis of coumarins to obtain new candidates for treating Alzheimer’s Disease (AD, an unusual rearrangement of a benzopyran group to a benzofuran group occurred, offering a novel synthesis pathway of these benzofuran derivatives. The possible mechanism of the novel rearrangement was also discussed. All of the benzofuran derivatives have weak anti-AChE activities compared with the reference compound, donepezil.

  15. Synthesis, characterization and carbonic anhydrase inhibitory activity of novel benzothiazole derivatives.

    Science.gov (United States)

    Küçükbay, F Zehra; Buğday, Nesrin; Küçükbay, Hasan; Tanc, Muhammet; Supuran, Claudiu T

    2016-12-01

    N-protected amino acids were reacted with substituted benzothiazoles to give the corresponding N-protected amino acid-benzothiazole conjugates (60-89%). Their structures were confirmed by proton nuclear magnetic resonance ((1)H NMR), carbon-13 nuclear magnetic resonance ((13)C NMR), IR and elemental analysis. Their carbonic anhydrase (CA, EC 4.2.1.1) inhibitory activities were determined against two cytosolic human isoforms (hCA I and hCA II), one membrane-associated (hCA IV) and one transmembrane (hCA XII) enzyme by a stopped-flow CO2 hydrase assay method. The new compounds showed rather weak, micromolar inhibitory activity against most of these enzymes.

  16. Synthesis and topoisomerase II inhibitory and cytotoxic activity of oxiranylmethoxy- and thiiranylmethoxy-chalcone derivatives.

    Science.gov (United States)

    Na, Younghwa; Nam, Jung-Min

    2011-01-01

    In order to find potential anticancer drug candidate targeting topoisomerases enzyme, we have designed and synthesized oxiranylmethoxy- and thiiranylmethoxy-retrochalcone derivatives and evaluated their pharmacological activity including topoisomerases inhibitory and cytotoxic activity. Of the compounds prepared compound 25 showed comparable or better cytotoxic activity against cancer cell lines tested. Compound 25 inhibited MCF7 (IC(50): 0.49 ± 0.21 μM) and HCT15 (IC(50): 0.23 ± 0.02 μM) carcinoma cell growth more efficiently than references. In the topoisomerases inhibition test, all the compounds were inactive to topoisomerase I but moderate inhibitors to topoisomerase II enzyme. Especially, compound 25 inhibited topoisomerase II activity with comparable extent to etoposide at 100 μM concentrations. Correlation between cytotoxicity and topoisomerase II inhibitory activity implies that compound 25 can be a possible lead compound for anticancer drug impeding the topoisomerase II function.

  17. Cellulose produced by Gluconacetobacter xylinus strains ATCC 53524 and ATCC 23768: Pellicle formation, post-synthesis aggregation and fiber density.

    Science.gov (United States)

    Lee, Christopher M; Gu, Jin; Kafle, Kabindra; Catchmark, Jeffrey; Kim, Seong H

    2015-11-20

    The pellicle formation, crystallinity, and bundling of cellulose microfibrils produced by bacterium Gluconacetobacter xylinus were studied. Cellulose pellicles were produced by two strains (ATCC 53524 and ATCC 23769) for 1 and 7 days; pellicles were analyzed with scanning electron microscopy (SEM), X-ray diffraction (XRD), vibrational sum-frequency-generation (SFG) spectroscopy, and attenuated total reflectance infrared (ATR-IR) spectroscopy. The bacterial cell population was higher at the surface exposed to air, indicating that the newly synthesized cellulose is deposited at the top of the pellicle. XRD, ATR-IR, and SFG analyses found no significant changes in the cellulose crystallinity, crystal size or polymorphic distribution with the culture time. However, SEM and SFG analyses revealed cellulose macrofibrils produced for 7 days had a higher packing density at the top of the pellicle, compared to the bottom. These findings suggest that the physical properties of cellulose microfibrils are different locally within the bacterial pellicles.

  18. Synthesis and Structural Studies of Some Inorganic Polymers of Succinoyl Carboxymethyl Cellulose

    Directory of Open Access Journals (Sweden)

    H. D. Juneja

    2011-01-01

    Full Text Available The inorganic polymers containing transition metals such as Mn(II, Co(II, Ni(II, Cu(II and Zn(II were synthesized by using succinoyl carboxymethyl cellulose (SCMC in aqueous media. The newly synthesized polymers were characterized by elemental analysis, IR spectroscopy, TG analysis, UV reflectance spectra and magnetic moment. On the basis of these studies, the composition of the polymeric unit was found to be [M(IIL]n, [Mʼ(IIL.2H2 O]n, {[Mˮ(IIL.2H2O]n H2O}, where M= Zn(II, Mʼ = Mn(II, Ni(II and Cu(II and Mˮ = Co(II, L = SCMC ligand. On the basis of instrumental techniques, it has been found that the [Zn(II(SCMC]n inorganic polymer has tetrahedral geometry, whereas {[Cu(II(SCMC].2H2O}n has square planar geometry and [Mn(II(SCMC.2H2O]n, {[Co(II(SCMC.2H2O].H2O}n and [Ni(II (SCMC.2H2O]n have octahedral geometry. The decomposition temperatures of the inorganic polymers have been determined by TGA. The TGA reveal that the Mn(II polymer of SCMC is highly thermally stable than rest of the polymers and these polymers can be used as thermal resisting materials.

  19. Synthesis and characterization of carboxymethyl cellulose from office waste paper: a greener approach towards waste management.

    Science.gov (United States)

    Joshi, Gyanesh; Naithani, Sanjay; Varshney, V K; Bisht, Surendra S; Rana, Vikas; Gupta, P K

    2015-04-01

    In the present study, functionalization of mixed office waste (MOW) paper has been carried out to synthesize carboxymethyl cellulose, a most widely used product for various applications. MOW was pulped and deinked prior to carboxymethylation. The deinked pulp yield was 80.62 ± 2.0% with 72.30 ± 1.50% deinkability factor. The deinked pulp was converted to CMC by alkalization followed by etherification using NaOH and ClCH2COONa respectively, in an alcoholic medium. Maximum degree of substitution (DS) (1.07) of prepared CMC was achieved at 50 °C with 0.094 M and 0.108 M concentrations of NaOH and ClCH2COONa respectively for 3h reaction time. The rheological characteristics of 1-3% aqueous solution of optimized CMC product showed the non-Newtonian pseudoplastic behavior. Fourier transform infra red (FTIR), nuclear magnetic resonance (NMR) and scanning electron microscope (SEM) study were used to characterize the CMC product. Copyright © 2014 Elsevier Ltd. All rights reserved.

  20. Synthesis of nano cellulose fibers and effect on thermoplastics starch based films.

    Science.gov (United States)

    Savadekar, N R; Mhaske, S T

    2012-06-01

    Starch based films limit their application due to highly hydrophilic nature and poor mechanical properties. This problem was sought to be overcome by forming a nanocomposite of Thermoplastic starch (TPS) and Nano-Cellulose fibers (NCF). NCF was successfully synthesised from short stable cotton fibres by a chemo-mechanical process. TPS/NCF composite films were prepared by solution casting method, and their characterizations were done in terms of differential scanning calorimeter (DSC), morphology (SEM), water vapor permeability (WVTR), oxygen transmission rate (OTR), X-ray diffractograms, light transmittance and tensile properties. At very low concentration of NCF filled TPS composite film showed improvement in properties. The 0.4 t% NCF loaded TPS films showed 46.10% improved tensile strength than by base polymer film, beyond that 0.5 t% concentration tensile strength starts to deteriorate. WVTR and OTR results showed improved water vapor barrier property of TPS matrix. The DSC thermograms of TPS and composite films did not show any significant effect on the melting point of composite film to the base polymer TPS.

  1. Synthesis and Fabrication of Nanocomposite Fibers of Collagen-Cellulose Nanocrystals by Coelectrocompaction.

    Science.gov (United States)

    Cudjoe, Elvis; Younesi, Mousa; Cudjoe, Edward; Akkus, Ozan; Rowan, Stuart J

    2017-04-10

    An electrochemical process has been used to compact cellulose nanocrystals (CNC) and access aligned micron-sized CNC fibers. Placing a current across aqueous solutions of carboxylic acid functionalized CNCs (t-CNC-COOH) or carboxylic acid/primary amine functionalized CNCs (t-CNC-COOH-NH2) creates a pH gradient between the electrodes, which results in the migration and concentration of the CNC fibers at their isoelectric point. By matching the carboxylic acid/amine ratio of CNCs and collagen (ca. 30:70 carboxylic acid:amine ratio), it is possible to coelectrocompact both nanofibers and access aligned nanocomposite fibers. t-CNC-COOH-NH2/collagen fibers showed a maximum increase in mechanical properties at 5 wt % of t-CNC-COOH-NH2. Compared to collagen/CNC films which have no alignment in the plane of the films, the tensile properties of the aligned fibers show a significant enhancement in the wet mechanical properties (40 MPa vs 230 MPa) for the 5 wt % of t-CNC-COOH-NH2/collagen films and fiber, respectively.

  2. Synthesis and characterization of quaternized bacterial cellulose prepared in homogeneous aqueous solution.

    Science.gov (United States)

    Zhang, Hairong; Guo, Haijun; Wang, Bo; Shi, Silan; Xiong, Lian; Chen, Xinde

    2016-01-20

    In this work, bacterial cellulose (BC) was activated by ethylenediamine (EDA) and then dissolved in lithium chloride/N,N-dimethylacetamide (LiCl/DMAc) aqueous solutions. The resulting transparent solution was cast on a glass plate to prepare regenerated BC. Then cationic BC was prepared homogeneously by the reaction between regenerated BC and 3-chloro-2-hydroxypropyl-trimethyl ammonium chloride (CHPTAC) in a NaOH/urea aqueous solution. Structure and properties of the BC and its products were characterized by different techniques such as X-ray diffraction (XRD), Fourier transform spectroscopy (FT-IR), scanning electron microscopy (SEM) and thermo-gravimetric analysis (TGA). The results showed that there was no significant difference between the structures of BC, activated BC and regenerated BC. The effects of different temperature and molar ratio of CHPTAC to anhydroglucose unit (AGU) on the degree of substitution (DS) value were examined. The DS values of cationic BC ranged between 0.21 and 0.51.

  3. Thermoresponsive bacterial cellulose whisker/poly(NIPAM-co-BMA) nanogel complexes: synthesis, characterization, and biological evaluation.

    Science.gov (United States)

    Wu, Lei; Zhou, Hui; Sun, Hao-Jan; Zhao, Yanbing; Yang, Xiangliang; Cheng, Stephen Z D; Yang, Guang

    2013-04-08

    Dispersions of poly(N-isopropylacrylamide-co-butyl methacrylate) (PNB) nanogels are known to exhibit reversible thermosensitive sol-gel phase behavior and can consequently be used in a wide range of biomedical applications. However, some dissatisfactory mechanical properties of PNB nanogels can limit their applications. In this paper, bacterial cellulose (BC) whiskers were first prepared by sulfuric acid hydrolysis and then nanosized by high-pressure homogenization for subsequent use in the preparation of BC whisker/PNB nanogel complexes (designated as BC/PNB). The mechanical properties of PNB was successfully enhanced, resulting in good biosafety. The BC/PNB nanogel dispersions exhibited phase transitions from swollen gel to shrunken gel with increasing temperature. In addition, differential scanning calorimetry (DSC) data showed that the thermosensitivity of PNB nanogels was retained. Rheological tests also indicated that BC/PNB nanogel complexes had stronger gel strengths when compared with PNB nanogels. The concentrated dispersions showed shear thinning behavior and improved toughness, both of which can play a key role in the medical applications of nanogel complexes. Furthermore, the BC/PNB nanogel complexes were noncytotoxic according to cytotoxicity and hemolysis tests. Concentrated BC/PNB nanogel dispersion displayed gel a forming capacity in situ by catheter injection, which indicates potential for a wide range of medical applications.

  4. Synthesis of Platinum Nanoparticles from K2PtCl4 Solution Using Bacterial Cellulose Matrix

    Directory of Open Access Journals (Sweden)

    H. F. Aritonang

    2014-01-01

    Full Text Available Platinum (Pt nanoparticles have been synthesized from a precursor solution of potassium tetrachloroplatinate (K2PtCl4 using a matrix of bacterial cellulose (BC. The formation of Pt nanoparticles occurs at the surface and the inside of the BC membrane by reducing the precursor solution with a hydrogen gas reductant. The Pt nanoparticles obtained from the variations of precursor concentration, between 3 mM and 30 mM, and the formation of Pt nanoparticles have been studied using X-ray diffraction (XRD, scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDS, and thermogravimetry analysis (TGA. Based on X-ray diffraction patterns, Pt particles have sizes between 6.3 nm and 9.3 nm, and the Pt particle size increases with an increase in precursor concentration. The morphology of the Pt nanoparticles was observed by SEM-EDS and the content of Pt particles inside the membrane is higher than that on the surface of BC membranes. This analysis corresponds to the TGA analysis, but the TGA analysis is more representative in how it describes the content of Pt particles in the BC membrane.

  5. Pyranoxanthones: Synthesis, growth inhibitory activity on human tumor cell lines and determination of their lipophilicity in two membrane models

    DEFF Research Database (Denmark)

    Goncalves de Azavedo, Carlos M. B. P.; Afonso, C. M.; Soares, J. X.;

    2013-01-01

    The benzopyran and dihydrobenzopyran moieties can be considered as "privileged motifs" in drug discovery being good platforms for the search of new bioactive compounds. These moieties are commonly found fused to the xanthonic scaffold belonging to the biologically important family of the generally...... hard to be established. Accordingly, with the aim of rationalizing the importance of the fused ring orientation and oxygenation pattern in pyranoxanthones, this study describes the synthesis of 14 new pyranoxanthones and evaluation of their cell growth inhibitory activity in four human tumor cell lines...... as well as their lipophilicity in two membrane models. This systematic approach allowed establishing structure-activity and structure-lipophilicity relationships for the obtained compounds in combination with 6 previously described compounds. From this work an angular pyranoxanthone scaffold emerged...

  6. A new series of diarylamides possessing quinoline nucleus: Synthesis, in vitro anticancer activities, and kinase inhibitory effect.

    Science.gov (United States)

    El-Gamal, Mohammed I; Khan, Mohammad Ashrafuddin; Abdel-Maksoud, Mohammed S; Gamal El-Din, Mahmoud M; Oh, Chang-Hyun

    2014-11-24

    Synthesis of a new series of diarylamides possessing 6,7-dimethoxy(dihydroxy)quinoline scaffold is described. Their in vitro antiproliferative activities against NCI-58 human cancer cell lines of nine different cancer types were tested. Compounds 1a and 1d-g showed the highest mean %inhibition values over the 58 cell line panel at 10 μM, and they were further tested in 5-dose testing mode to determine their IC50 values. The five compounds were more potent than Imatinib against all the cell lines of nine different cancer types. Compound 1g showed the highest potencies. It showed inhibitory effect against C-RAF kinase (76.65% at 10 μM concentration).

  7. Phyto-synthesis of silver nanoscale particles using Morinda citrifolia L. and its inhibitory activity against human pathogens.

    Science.gov (United States)

    Sathishkumar, Gnanasekar; Gobinath, Chandrakasan; Karpagam, Karuppiah; Hemamalini, Vedagiri; Premkumar, Kumpati; Sivaramakrishnan, Sivaperumal

    2012-06-15

    Leaf extract of Morinda citrifolia L. was assessed for the synthesis of silver nanoscale particles under different temperature and reaction time. Synthesized nanoscale (MCAgNPs) particles were confirmed by analysing the excitation of surface plasmon resonance (SPR) using UV-visible spectrophotometer at 420 nm. Further SEM, HRTEM analysis confirmed the range of particle size between 10 and 60 nm and SEAD pattern authorizes the face centered cubic (fcc) crystalline nature of the MCAgNPs. Fourier transform infrared spectrum (FTIR) of synthesized MCAgNPs confirms the presence of high amount of phenolic compounds in the plant extract which may possibly influence the reduction process and stabilization of nanoparticles. Further, inhibitory activity of MCAgNPs and plant extract were tested against human pathogens like Eschericia coli, Pseudomonas aeroginosa, Klebsiella pneumoniae, Enterobacter aerogenes, Bacillus cereus and Enterococci sp. The results indicated that the MCAgNPs showed moderate inhibitory actions against human pathogens than crude plant extract, demonstrating its antimicrobial value against pathogenic diseases.

  8. A synthesis of evidence on inhibitory control and auditory hallucinations based on the Research Domain Criteria (RDoC framework.

    Directory of Open Access Journals (Sweden)

    Johanna C. Badcock

    2014-03-01

    Full Text Available The National Institute of Mental Health initiative called the Research Domain Criteria (RDoC project aims to provide a new approach to understanding mental illness grounded in the fundamental domains of human behaviour and psychological functioning. To this end the RDoC framework encourages researchers and clinicians to think outside the [diagnostic]box, by studying symptoms, behaviours or biomarkers that cut across traditional mental illness categories. In this article we examine and discuss how the RDoC framework can improve our understanding of psychopathology by zeroing in on hallucinations- now widely recognized as a symptom that occurs in a range of clinical and non-clinical groups. We focus on a single domain of functioning - namely cognitive [inhibitory] control - and assimilate key findings structured around the basic RDoC units of analysis, which span the range from observable behaviour to molecular genetics. Our synthesis and critique of the literature provides a deeper understanding of the mechanisms involved in the emergence of auditory hallucinations, linked to the individual dynamics of inhibitory development before and after puberty; favours separate developmental trajectories for clinical and nonclinical hallucinations; yields new insights into co-occurring emotional and behavioural problems; and suggests some novel avenues for treatment.

  9. Review: Regulatory mechanisms of gonadotropin-inhibitory hormone (GnIH synthesis and release in photoperiodic animals

    Directory of Open Access Journals (Sweden)

    Kazuyoshi eTsutsui

    2013-04-01

    Full Text Available Gonadotropin-inhibitory hormone (GnIH is a novel hypothalamic neuropeptide that was discovered in quail as an inhibitory factor for gonadotropin release. GnIH inhibits gonadotropin synthesis and release in birds through actions on gonadotropin-releasing hormone (GnRH neurons and gonadotropes, mediated via the GnIH receptor (GnIH-R, GPR147. Subsequently, GnIH was identified in mammals and other vertebrates. As in birds, mammalian GnIH inhibits gonadotropin secretion, indicating a conserved role for this neuropeptide in the control of the hypothalamic-pituitary-gonadal (HPG axis across species. Identification of the regulatory mechanisms governing GnIH expression and release is important in understanding the physiological role of the GnIH system. A nocturnal hormone, melatonin, appears to act directly on GnIH neurons through its receptor to induce expression and release of GnIH in quail, a photoperiodic bird. Recently, a similar, but opposite, action of melatonin on the inhibition of expression of mammalian GnIH was shown in hamsters and sheep, photoperiodic mammals. These results in photoperiodic animals demonstrate that GnIH expression is photoperiodically modulated via a melatonin-dependent process. Recent findings indicate that GnIH may be a mediator of stress-induced reproductive disruption in birds and mammals, pointing to a broad role for this neuropeptide in assessing physiological state and modifying reproductive effort accordingly. This paper summarizes the advances made in our knowledge regarding the regulation of GnIH synthesis and release in photoperiodic birds and mammals. This paper also discusses the neuroendocrine integration of environmental signals, such as photoperiods and stress, and internal signals, such as GnIH, melatonin and glucocorticoids, to control avian and mammalian reproduction.

  10. Synthesis of Triazole Schiff's Base Derivatives and Their Inhibitory Kinetics on Tyrosinase Activity.

    Directory of Open Access Journals (Sweden)

    Feng Yu

    Full Text Available In the present study, new Schiff's base derivatives: (Z-4-amino-5-(2-(3- fluorobenzylidenehydrazinyl-4H-1,2,4-triazole-3-thiol (Y1, (Z-3-((2-(4-amino-5- mercapto-4H-1,2,4-triazol-3-ylhydrazonomethylphenol (Y2, (Z-2-((2-(4-amino-5- mercapto-4H-1,2,4-triazol-3-ylhydrazonomethylphenol (Y3 and 3-((Z-(2-(4- (((E-3-hydroxybenzylideneamino-5-mercapto-4H-1,2,4-triazol-3-ylhydrazonomethylphenol (Y4 were synthesized and their structures were characterized by LC-MS, IR and 1H NMR. The inhibitory effects of these compounds on tyrosinase activites were evaluated. Compounds Y1, Y2 and Y3 showed potent inhibitory effects with respective IC50 value of 12.5, 7.0 and 1.5 μM on the diphenolase activities. Moreover, the inhibition mechanisms were determined to be reversible and mixed types. Interactions of the compounds with tyrosinase were further analyzed by fluorescence quenching, copper interaction, and molecular simulation assays. The results together with the anti-tyrosinase activities data indicated that substitution on the second position of benzene ring showed superior ant-ityrosinase activities than that on third position, and that hydroxyl substitutes were better than fluorine substitutes. In addition, two benzene rings connecting to the triazole ring would produce larger steric hindrance, and affect the bonding between tyrosinase and inhibitors to decrease the inhibitory effects. The anti-tyrosinase effects of these compounds were in contrast to their antioxidant activities. In summary, this research will contribute to the development and design of antityrosinase agents.

  11. Cultivation and utilization of specific wood biomass for synthesis of cellulose based bioethanol

    Energy Technology Data Exchange (ETDEWEB)

    Fara, L.; Comaneci, D. [Polytechnic Univ. of Bucharest, Bucharest (Romania). Faculty of Applied Sciences; Cincu, C.; Hubca, G.; Zaharia, C.; Diacon, A. [Polytechnic Univ. of Bucharest, Bucharest (Romania). Faculty of Applied Chemistry; Filat, M.; Chira, D. [Forest Research and Management Inst., Ilfov (Romania); Nutescu, C. [National Wood Inst., Bucharest (Romania); Fara, S. [Inst. for Research and Design of Automation, Bucharest (Romania)

    2010-07-01

    The energetic characteristics of 6 types of poplar clones cultivated for different pedoclimatic conditions in Romania were determined. Four clones were developed in Italy and 2 in Romania. Five experimental cultures were used to analyze the plant survival rate and biomass production rate. After 2 years of study, the Italian clones were found to have very good adaptability to the pedoclimatic conditions in Romania in comparison with local clones. The Italian clones Monviso and AF-6 registered the most substantial growths and the highest resistance to disease. Bioethanol was synthesized by acidic hydrolysis of the cellulose using 2 approaches. In the first approach the lignocellulosic raw material was hydrolyzed with diluted sulfuric acid at 50 degrees C for 24 hours. After filtration, the solid residue was treated with 30 per cent H{sub 2}SO{sub 4} at 100 degrees C for 6 hours. The resulting solutions were neutralized with Ca(OH){sub 2} following another filtration and the resulted solution with pH 6.5 was subjected to fermentation with Saccharomices Cerevisiae. In the second approach the lignocellulosic raw material was subjected to hydrolysis with 10 per cent H{sub 2}SO{sub 4} at 100 degrees C for 4 hours. After filtration, the solid residue was hydrolyzed with 30 per cent H{sub 2}SO{sub 4} at 100 degrees for 6 hours. The solution was neutralized with Ca(OH){sub 2} and subjected to alcoholic fermentation with Saccharomices Cerevisiae. The fermentation took place at 25 degrees C for 72 hours. The results for the two methods were similar.

  12. Synthesis, structure and antimicrobial property of green composites from cellulose, wool, hair and chicken feather.

    Science.gov (United States)

    Tran, Chieu D; Prosencyes, Franja; Franko, Mladen; Benzi, Gerald

    2016-10-20

    Novel composites between cellulose (CEL) and keratin (KER) from three different sources (wool, hair and chicken feather) were successfully synthesized in a simple one-step process in which butylmethylimidazolium chloride (BMIm(+)Cl(-)), an ionic liquid, was used as the sole solvent. The method is green and recyclable because [BMIm(+)Cl(-)] used was recovered for reuse. Spectroscopy (FTIR, XRD) and imaging (SEM) results confirm that CEL and KER remain chemically intact and homogeneously distributed in the composites. KER retains some of its secondary structure in the composites. Interestingly, the minor differences in the structure of KER in wool, hair and feather produced pronounced differences in the conformation of their corresponding composites with wool has the highest α-helix content and feather has the lowest content. These results correlate well with mechanical and antimicrobial properties of the composites. Specifically, adding CEL into KER substantially improves mechanical strength of [CEL+KER] composites made from all three different sources, wool, hair and chicken feathers i.e., [CEL+wool], [CEL+hair] and [CEL+feather]. Since mechanical strength is due to CEL, and CEL has only random structure, [CEL+feather] has, expectedly, the strongest mechanical property because feather has the lowest content of α-helix. Conversely, [CEL+wool] composite has the weakest mechanical strength because wool has the highest α-helix content. All three composites exhibit antibacterial activity against methicillin resistant Staphylococcus aureus (MRSA). The antibacterial property is due not to CEL but to the protein and strongly depends on the type of the keratin, namely, the bactericidal effect is strongest for feather and weakest for wool. These results together with our previous finding that [CEL+KER] composites can control release of drug such as ciprofloxacin clearly indicate that these composites can potentially be used as wound dressing.

  13. Inhibitory effect of melatonin on testosterone synthesis is mediated via GATA-4/SF-1 transcription factors.

    Science.gov (United States)

    Qin, Fenju; Zhang, Jie; Zan, Linsen; Guo, Weiqiang; Wang, Jin; Chen, Lili; Cao, Yi; Shen, Ouxi; Tong, Jian

    2015-11-01

    The aim of the present study was to elucidate whether the GATA-4/SF-1 signalling pathway is involved in the inhibitory effects of melatonin on testosterone production in both the TM3 Leydig cell line and in C57BL/6J mice. In-vitro experiments demonstrated that melatonin treatment significantly reduced testosterone levels in cell culture medium (P SF-1 (NR5A1), StAR, P450SCC (CYP11A1) and 3β-HSD (P SF-1 (P SF-1 expression.

  14. Synthesis of rotenoid derivatives with cytotoxic and topoisomerase II inhibitory activities.

    Science.gov (United States)

    Sangthong, Supranee; Krusong, Kuakarun; Ngamrojanavanich, Nattaya; Vilaivan, Tirayut; Puthong, Songchan; Chandchawan, Supajittra; Muangsin, Nongnuj

    2011-08-15

    6-Deoxyclitoriacetal (1) and a series of 11 further derivatives of it (2-12) were synthesized and evaluated for their cytotoxic and topoisomerase IIα inhibitory activities. Compounds bearing epoxide (2), morpholine (6) and benzylamine (10) moieties showed promising in vitro cytotoxic activities against four cancer cell lines, with IC(50) values ranging from 0.38 to 0.73 μM. These three compounds also strongly inhibited topoisomerase II activity at 68.3-93.5% and showed a moderately high DNA intercalating property.

  15. A New Synthesis Method and GABA Transporters Inhibitory Activities of Tiagabine and Its Analogues

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    A new synthetic method and GABA transporter inhibitory activities of Tiagabine and its analogues are described.The key intermediates 4-tosyl-1,1-diaryl/heteroaryl-1-butene 10a-10e were synthesized by Wittig reaction, and followed by N-alkylation with (R)-3-piperidinecarboxylate. The resultingN-diheterocyclylalkenylpiperidine-3-carboxylic acid ester 11a-11e were saponified and then acidified toget the target compounds 1a-1e. The preliminary bioassays show that compound 1a-1e exhibited excellent inhibition of [3H]-GABA uptake in vitro of culture cells.

  16. Design, Synthesis, and Inhibitory Activity of Potent, Photoswitchable Mast Cell Activation Inhibitors

    NARCIS (Netherlands)

    Velema, Willem A.; van der Toorn, Marco; Szymanski, Wiktor; Feringa, Ben L.

    2013-01-01

    Allergic reactions affect millions of people worldwide. The need for new and effective antiallergic agents is evident, and insight into the underlying mechanisms that lead to allergic events is necessary. Herein, we report the design, synthesis, and activity of photoswitchable mast cell activation

  17. Design, Synthesis, and Inhibitory Activity of Potent, Photoswitchable Mast Cell Activation Inhibitors

    NARCIS (Netherlands)

    Velema, Willem A.; van der Toorn, Marco; Szymanski, Wiktor; Feringa, Ben L.

    2013-01-01

    Allergic reactions affect millions of people worldwide. The need for new and effective antiallergic agents is evident, and insight into the underlying mechanisms that lead to allergic events is necessary. Herein, we report the design, synthesis, and activity of photoswitchable mast cell activation i

  18. Inhibitory Effect of Arctigenin from Fructus Arctii Extract on Melanin Synthesis via Repression of Tyrosinase Expression.

    Science.gov (United States)

    Park, Hwayong; Song, Kwang Hoon; Jung, Pil Mun; Kim, Ji-Eun; Ro, Hyunju; Kim, Mi Yoon; Ma, Jin Yeul

    2013-01-01

    To identify the active compound arctigenin in Fructus Arctii (dried seed of medicinal plant Arctium lappa) and to elucidate the inhibitory mechanism in melanogenesis, we analyzed melanin content and tyrosinase activity on B16BL6 murine melanoma and melan-A cell cultures. Water extracts of Fructus Arctii were shown to inhibit tyrosinase activity in vitro and melanin content in α -melanocyte stimulating hormone-stimulated cells to similar levels as the well-known kojic acid and arbutin, respectively. The active compound arctigenin of Fructus Arctii displayed little or no cytotoxicity at all concentrations examined and decreased the relative melanin content and tyrosinase activity in a dose-dependent manner. Melanogenic inhibitory activity was also identified in vivo with zebrafish embryo. To determine the mechanism of inhibition, the effects of arctigenin on tyrosinase gene expression and tyrosinase promoter activity were examined. Also in addition, in the signaling cascade, arctigenin dose dependently decreased the cAMP level and promoted the phosphorylation of extracellular signal-regulated kinase. This result suggests that arctigenin downregulates cAMP and the tyrosinase enzyme through its gene promoter and subsequently upregulates extracellular signal-regulated kinase activity by increasing phosphorylation in the melanogenesis signaling pathway, which leads to a lower melanin content.

  19. Design, Synthesis and hMAO Inhibitory Screening of Novel 2-Pyrazoline Analogues.

    Science.gov (United States)

    Aksöz, Begüm Evranos; Uçar, Gülberk; Yelekçi, Kemal

    2017-05-03

    A series of 3,5-diaryl-2-pyrazoline derivatives was synthesized via the reaction of various chalcones with hydrazide compounds in ethanol. Structural elucidation of the compounds was performed by IR, 1H NMR, 13C NMR, mass spectral data, and elemental analyses. The new compounds were tested for their human monoamine oxidase (hMAO) inhibitory activities. All compounds were found to be competitive, reversible, and selective inhibitors for hMAO-A. Compounds 5a, 5b, 5f, 5h, 5i and 5l showed higher selectivity towards hMAO than moclobemide, the known selective and competitive hMAO-A inhibitor. Compounds 5c, 5d, 5i and 5l exhibited also higher inhibitory potency towards hMAO-A than moclobemide. The AutoDock 4.2 program was employed to perform automated molecular docking. The calculated results obtained computationally were in good agreement with the experimental values. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  20. Inhibitory Effect of Arctigenin from Fructus Arctii Extract on Melanin Synthesis via Repression of Tyrosinase Expression

    Science.gov (United States)

    Park, Hwayong; Song, Kwang Hoon; Jung, Pil Mun; Kim, Ji-Eun; Kim, Mi Yoon; Ma, Jin Yeul

    2013-01-01

    To identify the active compound arctigenin in Fructus Arctii (dried seed of medicinal plant Arctium lappa) and to elucidate the inhibitory mechanism in melanogenesis, we analyzed melanin content and tyrosinase activity on B16BL6 murine melanoma and melan-A cell cultures. Water extracts of Fructus Arctii were shown to inhibit tyrosinase activity in vitro and melanin content in α-melanocyte stimulating hormone-stimulated cells to similar levels as the well-known kojic acid and arbutin, respectively. The active compound arctigenin of Fructus Arctii displayed little or no cytotoxicity at all concentrations examined and decreased the relative melanin content and tyrosinase activity in a dose-dependent manner. Melanogenic inhibitory activity was also identified in vivo with zebrafish embryo. To determine the mechanism of inhibition, the effects of arctigenin on tyrosinase gene expression and tyrosinase promoter activity were examined. Also in addition, in the signaling cascade, arctigenin dose dependently decreased the cAMP level and promoted the phosphorylation of extracellular signal-regulated kinase. This result suggests that arctigenin downregulates cAMP and the tyrosinase enzyme through its gene promoter and subsequently upregulates extracellular signal-regulated kinase activity by increasing phosphorylation in the melanogenesis signaling pathway, which leads to a lower melanin content. PMID:23781272

  1. Inhibitory Effect of Arctigenin from Fructus Arctii Extract on Melanin Synthesis via Repression of Tyrosinase Expression

    Directory of Open Access Journals (Sweden)

    Hwayong Park

    2013-01-01

    Full Text Available To identify the active compound arctigenin in Fructus Arctii (dried seed of medicinal plant Arctium lappa and to elucidate the inhibitory mechanism in melanogenesis, we analyzed melanin content and tyrosinase activity on B16BL6 murine melanoma and melan-A cell cultures. Water extracts of Fructus Arctii were shown to inhibit tyrosinase activity in vitro and melanin content in α-melanocyte stimulating hormone-stimulated cells to similar levels as the well-known kojic acid and arbutin, respectively. The active compound arctigenin of Fructus Arctii displayed little or no cytotoxicity at all concentrations examined and decreased the relative melanin content and tyrosinase activity in a dose-dependent manner. Melanogenic inhibitory activity was also identified in vivo with zebrafish embryo. To determine the mechanism of inhibition, the effects of arctigenin on tyrosinase gene expression and tyrosinase promoter activity were examined. Also in addition, in the signaling cascade, arctigenin dose dependently decreased the cAMP level and promoted the phosphorylation of extracellular signal-regulated kinase. This result suggests that arctigenin downregulates cAMP and the tyrosinase enzyme through its gene promoter and subsequently upregulates extracellular signal-regulated kinase activity by increasing phosphorylation in the melanogenesis signaling pathway, which leads to a lower melanin content.

  2. Cellulose as an adhesion agent for the synthesis of lignin aerogel with strong mechanical performance, Sound-absorption and thermal Insulation

    Science.gov (United States)

    Wang, Chao; Xiong, Ye; Fan, Bitao; Yao, Qiufang; Wang, Hanwei; Jin, Chunde; Sun, Qingfeng

    2016-08-01

    The lignin aerogels that are both high porosity and compressibility would have promising implications for bioengineering field to sound-adsorption and damping materials; however, creating this aerogel had a challenge to adhesive lignin. Here we reported cellulose as green adhesion agent to synthesize the aerogels with strong mechanical performance. Our approach—straightforwardly dissolved in ionic liquids and simply regenerated in the deionized water—causes assembly of micro-and nanoscale and even molecule level of cellulose and lignin. The resulting lignin aerogels exhibit Young’s modulus up to 25.1 MPa, high-efficiency sound-adsorption and excellent thermal insulativity. The successful synthesis of this aerogels developed a path for lignin to an advanced utilization.

  3. Cellulose as an adhesion agent for the synthesis of lignin aerogel with strong mechanical performance, Sound-absorption and thermal Insulation.

    Science.gov (United States)

    Wang, Chao; Xiong, Ye; Fan, Bitao; Yao, Qiufang; Wang, Hanwei; Jin, Chunde; Sun, Qingfeng

    2016-08-26

    The lignin aerogels that are both high porosity and compressibility would have promising implications for bioengineering field to sound-adsorption and damping materials; however, creating this aerogel had a challenge to adhesive lignin. Here we reported cellulose as green adhesion agent to synthesize the aerogels with strong mechanical performance. Our approach-straightforwardly dissolved in ionic liquids and simply regenerated in the deionized water-causes assembly of micro-and nanoscale and even molecule level of cellulose and lignin. The resulting lignin aerogels exhibit Young's modulus up to 25.1 MPa, high-efficiency sound-adsorption and excellent thermal insulativity. The successful synthesis of this aerogels developed a path for lignin to an advanced utilization.

  4. Plasma-enhanced synthesis of bactericidal quaternary ammonium thin layers on stainless steel and cellulose surfaces.

    Science.gov (United States)

    Jampala, Soujanya N; Sarmadi, M; Somers, E B; Wong, A C L; Denes, F S

    2008-08-19

    We have investigated bottom-up chemical synthesis of quaternary ammonium (QA) groups exhibiting antibacterial properties on stainless steel (SS) and filter paper surfaces via nonequilibrium, low-pressure plasma-enhanced functionalization. Ethylenediamine (ED) plasma under suitable conditions generated films rich in secondary and tertiary amines. These functional structures were covalently attached to the SS surface by treating SS with O 2 and hexamethyldisiloxane plasma prior to ED plasma treatment. QA structures were formed by reaction of the plasma-deposited amines with hexyl bromide and subsequently with methyl iodide. Structural compositions were examined by electron spectroscopy for chemical analysis and Fourier transform infrared spectroscopy, and surface topography was investigated with atomic force microscopy and water contact angle measurements. Modified SS surfaces exhibited greater than a 99.9% decrease in Staphylococcus aureus counts and 98% in the case of Klebsiella pneumoniae. The porous filter paper surfaces with immobilized QA groups inactivated 98.7% and 96.8% of S. aureus and K. pneumoniae, respectively. This technique will open up a novel way for the synthesis of stable and very efficient bactericidal surfaces with potential applications in development of advanced medical devices and implants with antimicrobial surfaces.

  5. Synthesis of hybrid cellulose nanocomposite bonded with dopamine SiO2/TiO2 and its antimicrobial activity

    Science.gov (United States)

    Ramesh, Sivalingam; Kim, Gwang-Hoon; Kim, Jaehwan; Kim, Joo-Hyung

    2015-04-01

    Organic-inorganic hybrid material based cellulose was synthesized by the sol-gel approach. The explosion of activity in this area in the past decade has made tremendous progress in industry or academic both fundamental understanding of sol-gel process and applications of new functionalized hybrid materials. In this present research work, we focused on cellulose-dopamine functionalized SiO2/TiO2 hybrid nanocomposite by sol-gel process. The cellulose-dopamine hybrid nanocomposite was synthesized via γ-aminopropyltriethoxysilane (γ-APTES) coupling agent by in-situ sol-gel process. The chemical structure of cellulose-amine functionalized dopamine bonding to cellulose structure with covalent cross linking hybrids was confirmed by FTIR spectral analysis. The morphological analysis of cellulose-dopamine nanoSiO2/TiO2 hybrid nanocomposite materials was characterized by XRD, SEM and TEM. From this different analysis results indicate that the optical transparency, thermal stability, control morphology of cellulose-dopamine-SiO2/TiO2 hybrid nanocomposite. Furthermore cellulose-dopamine-SiO2/TiO2 hybrid nanocomposite was tested against pathogenic bacteria for antimicrobial activity.

  6. CelR, an ortholog of the diguanylate cyclase PleD of Caulobacter, regulates cellulose synthesis in Agrobacterium tumefaciens.

    Science.gov (United States)

    Barnhart, D Michael; Su, Shengchang; Baccaro, Brenna E; Banta, Lois M; Farrand, Stephen K

    2013-12-01

    Cellulose fibrils play a role in attachment of Agrobacterium tumefaciens to its plant host. While the genes for cellulose biosynthesis in the bacterium have been identified, little is known concerning the regulation of the process. The signal molecule cyclic di-GMP (c-di-GMP) has been linked to the regulation of exopolysaccharide biosynthesis in many bacterial species, including A. tumefaciens. In this study, we identified two putative diguanylate cyclase genes, celR (atu1297) and atu1060, that influence production of cellulose in A. tumefaciens. Overexpression of either gene resulted in increased cellulose production, while deletion of celR, but not atu1060, resulted in decreased cellulose biosynthesis. celR overexpression also affected other phenotypes, including biofilm formation, formation of a polar adhesion structure, plant surface attachment, and virulence, suggesting that the gene plays a role in regulating these processes. Analysis of celR and Δcel mutants allowed differentiation between phenotypes associated with cellulose production, such as biofilm formation, and phenotypes probably resulting from c-di-GMP signaling, which include polar adhesion, attachment to plant tissue, and virulence. Phylogenetic comparisons suggest that species containing both celR and celA, which encodes the catalytic subunit of cellulose synthase, adapted the CelR protein to regulate cellulose production while those that lack celA use CelR, called PleD, to regulate specific processes associated with polar localization and cell division.

  7. Synthesis and characterization of a porous and hydrophobic cellulose-based composite for efficient and fast oil-water separation.

    Science.gov (United States)

    Wang, Xiangyun; Xu, Shimei; Tan, Yun; Du, Juan; Wang, Jide

    2016-04-20

    Oily wastewater is generated in diverse industrial processes, and its treatment has become crucial due to increasing environmental concerns. Herein, silanized cellulose was prepared by sol-gel reaction between microcrystalline cellulose (MCC) and hexadecyltrimethoxysilane (HDTMS) using for oil-water separation. The silanized cellulose was characterized by Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), scanning electron microscopy (SEM) and thermal gravimetric analysis (TGA). A higher mass ratio of HDTMS to MCC made silanized cellulose become looser, and showed lower water absorbency. The silanized cellulose exhibited specific separation performance towards vegetable oil-water mixture (not for mineral oil-water mixture) with separation efficiency of 99.93%. Moreover, the separation was fast with a water flux of 4628.5Lm(-2)h(-1). The separation efficiency still remained at 99.77% even after recycling for 10 times.

  8. Synthesis and acetylcholinesterase inhibitory activity of polyhydroxylated sulfated steroids: structure/activity studies.

    Science.gov (United States)

    Richmond, Victoria; Murray, Ana P; Maier, Marta S

    2013-11-01

    Disulfated and trisulfated steroids have been synthesized from cholesterol and their acetylcholinesterase inhibitory activity has been evaluated. In our studies we have found that the activity was not only dependent on the location of the sulfate groups but on their configurations. 2β,3α,6α-trihydroxy-5α-cholestan-6-one trisulfate (18) was the most active steroid with an IC50 value of 15.48 μM comparable to that of 2β,3α-dihydroxy-5α-cholestan-6-one disulfate (1). Both compounds were found to be less active than the reference compound eserine. The butyrylcholinesterase activity of 1 and 18 was one magnitude lower than that against acetylcholinesterase revealing a selective inhibitor profile.

  9. Synthesis of C-4-Substituted Steviol Derivatives and Their Inhibitory Effects against Hepatitis B Virus.

    Science.gov (United States)

    Lin, Shwu-Jiuan; Su, Ta-Chi; Chu, Chin-Nan; Chang, Yi-Chih; Yang, Li-Ming; Kuo, Yu-Cheng; Huang, Tsurng-Juhn

    2016-12-23

    ent-13-Hydroxykaur-16-ene-19-N-butylureide (6) was one of 33 synthesized C-4-substituted steviol derivatives that were evaluated for their effects on hepatitis B virus (HBV) surface antigen (HBsAg) secretion. The IC50 (16.9 μM) and SI (57.7) values for inhibiting HBV DNA replication of compound 6 were greater than those of the reference compound, lamivudine (3-TC; IC50: 107.5 μM; SI: 22.0). Thus, the anti-HBV mechanism of 6 was investigated, and it specifically inhibited viral gene expression and reduced viral DNA levels, as well as potently attenuated all of the viral promoter activity of HBV-expressing Huh7 cells. Examination of cellular signaling pathways found that 6 inhibited the activities of the nuclear factor (NF)-κB- and activator protein (AP)-1 element-containing promoters, but had no effects on AP-2 or interferon-stimulated response element (ISRE)-containing promoters in HBV-expressing cells. Meanwhile, it significantly eliminated NF-κB and extracellular signal-regulated kinase (ERK)/mitogen-activated protein kinase (MAPK) signaling-related protein levels and inhibited their phosphorylation in HBV-transfected Huh7 cells. The inhibitory potency of 6 against HBV DNA replication was reversed by cotransfecting the NF-κB p65 expression plasmid. Using the MAPK-specific activator anisomycin also reversed the inhibitory effect of 6 on viral DNA replication. The present findings suggest that the anti-HBV mechanism of 6 is partly mediated through the NF-κB and MAPK signaling pathways.

  10. Design, synthesis and inhibitory effect of pentapeptidyl chloromethyl ketones on proteinase K.

    Science.gov (United States)

    Kore, Anilkumar R; Shanmugasundaram, Muthian

    2010-12-01

    The synthesis and proteolytic inhibitor function of new modified pentapeptide MeOSuc-AAAPF-CH(2)Cl 6 is described. The efficacy of 6 in inhibiting the proteolytic activity of proteinase K at a concentration of 0.10 mM allows a signal to be obtained for an exogenous target ('Xeno RNA') at 29 PCR cycles (i.e., Ct=29), whereas the control MeOSuc-AAAPV-CH₂Cl 1 requires a 7.5-fold higher concentration (0.75 mM) to produce the same Ct.

  11. Controlled silver delivery by silver-cellulose nanocomposites prepared by a one-pot green synthesis assisted by microwaves

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Ana Rosa; Unali, Gianfranco, E-mail: ana.rosa.silva@ua.pt [Structured Materials Expertise Group, Unilever Discover Port Sunlight, Quarry Road East, Bebington CH63 3JW (United Kingdom)

    2011-08-05

    Controlled silver release from cellulosic nanocomposites was achieved by synthesizing silver nanoparticles, under microwave heating for 1-15 min, in a one-pot, versatile and sustainable process in which microcrystalline cellulose simultaneously functions as reducing, stabilizing and supporting agent in water; chitin, starch and other cellulose derivatives could also be used as reducing, stabilizing and supporting agents for silver nanoparticles and the method was also found to be extensible to the preparation of noble metal (Au, Pt) and metal oxide nanoparticle (ZnO, Cu, CuO and Cu{sub 2}O) nanocomposites.

  12. Novel chemical synthesis of ginkgolic acid (13:0) and evaluation of its tyrosinase inhibitory activity.

    Science.gov (United States)

    Fu, Yuanqing; Hong, Shan; Li, Duo; Liu, Songbai

    2013-06-05

    A novel efficient synthesis of ginkgolic acid (13:0) from abundant 2,6-dihydroxybenzoic acid was successfully developed through a state-of-the-art palladium-catalyzed cross-coupling reaction and catalytic hydrogenation with an overall yield of 34% in five steps. The identity of the synthesized ginkgolic acid (13:0) was confirmed by nuclear magnetic resonance, mass spectrometry, infrared, and high-performance liquid chromatography. The reaction sequence of this method can be readily extended to the synthesis of other ginkgolic acids. The synthesized ginkgolic acid (13:0) exhibited promising anti-tyrosinase activity (IC₅₀ = 2.8 mg/mL) that was not correlated to antioxidant activity as probed by 1,1-diphenyl-2-picrylhydrazyl, 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid), ferric reducing ability of plasma, and oxygen radical absorbance capacity assays. The synthetic strategy developed in this work will significantly facilitate biological studies of ginkgolic acids that have great potential applications in food and pharmaceuticals.

  13. Synthesis of 4-(2-substituted hydrazinyl)benzenesulfonamides and their carbonic anhydrase inhibitory effects.

    Science.gov (United States)

    Gul, Halise Inci; Kucukoglu, Kaan; Yamali, Cem; Bilginer, Sinan; Yuca, Hafize; Ozturk, Iknur; Taslimi, Parham; Gulcin, Ilhami; Supuran, Claudiu T

    2016-08-01

    In this study, 4-(2-substituted hydrazinyl)benzenesulfonamides were synthesized by microwave irradiation and their chemical structures were confirmed by (1)H NMR, (13)CNMR, and HRMS. Ketones used were: Acetophenone (S1), 4-methylacetophenone (S2), 4-chloroacetophenone (S3), 4-fluoroacetophenone (S4), 4-bromoacetophenone (S5), 4-methoxyacetophenone (S6), 4-nitroacetophenone (S7), 2-acetylthiophene (S8), 2-acetylfuran (S9), 1-indanone (S10), 2-indanone (S11). The compounds S9, S10 and S11 were reported for the first time, while S1-S8 was synthesized by different method than literature reported using microwave irradiation method instead of conventional heating in this study. The inhibitory effects of 4-(2-substituted hydrazinyl)benzenesulfonamide derivatives (S1-S11) against hCA I and II were studied. Cytosolic hCA I and II isoenzymes were potently inhibited by new synthesized sulphonamide derivatives with Kis in the range of 1.79 ± 0.22-2.73 ± 0.08 nM against hCA I and in the range of 1.72 ± 0.58-11.64 ± 5.21 nM against hCA II, respectively.

  14. Robust Synthesis of Ciprofloxacin-Capped Metallic Nanoparticles and Their Urease Inhibitory Assay

    Directory of Open Access Journals (Sweden)

    Muhammad Nisar

    2016-03-01

    Full Text Available The fluoroquinolone antibacterial drug ciprofloxacin (cip has been used to cap metallic (silver and gold nanoparticles by a robust one pot synthetic method under optimized conditions, using NaBH4 as a mild reducing agent. Metallic nanoparticles (MNPs showed constancy against variations in pH, table salt (NaCl solution, and heat. Capping with metal ions (Ag/Au-cip has significant implications for the solubility, pharmacokinetics and bioavailability of fluoroquinolone molecules. The metallic nanoparticles were characterized by several techniques such as ultraviolet visible spectroscopy (UV, atomic force microscopy (AFM, Fourier transform infrared spectroscopy (FTIR, scanning electron microscopy (SEM and energy dispersive X-ray (EDX methods. The nanoparticles synthesized using silver and gold were subjected to energy dispersive X-ray tests in order to show their metallic composition. The NH moiety of the piperazine group capped the Ag/Au surfaces, as revealed by spectroscopic studies. The synthesized nanoparticles were also assessed for urease inhibition potential. Fascinatingly, both Ag-cip and Au-cip NPs exhibited significant urease enzyme inhibitory potential, with IC50 = 1.181 ± 0.02 µg/mL and 52.55 ± 2.3 µg/mL, compared to ciprofloxacin (IC50 = 82.95 ± 1.62 µg/mL. MNPs also exhibited significant antibacterial activity against selected bacterial strains.

  15. Robust Synthesis of Ciprofloxacin-Capped Metallic Nanoparticles and Their Urease Inhibitory Assay.

    Science.gov (United States)

    Nisar, Muhammad; Khan, Shujaat Ali; Qayum, Mughal; Khan, Ajmal; Farooq, Umar; Jaafar, Hawa Z E; Zia-Ul-Haq, Muhammad; Ali, Rashid

    2016-03-25

    The fluoroquinolone antibacterial drug ciprofloxacin (cip) has been used to cap metallic (silver and gold) nanoparticles by a robust one pot synthetic method under optimized conditions, using NaBH₄ as a mild reducing agent. Metallic nanoparticles (MNPs) showed constancy against variations in pH, table salt (NaCl) solution, and heat. Capping with metal ions (Ag/Au-cip) has significant implications for the solubility, pharmacokinetics and bioavailability of fluoroquinolone molecules. The metallic nanoparticles were characterized by several techniques such as ultraviolet visible spectroscopy (UV), atomic force microscopy (AFM), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) methods. The nanoparticles synthesized using silver and gold were subjected to energy dispersive X-ray tests in order to show their metallic composition. The NH moiety of the piperazine group capped the Ag/Au surfaces, as revealed by spectroscopic studies. The synthesized nanoparticles were also assessed for urease inhibition potential. Fascinatingly, both Ag-cip and Au-cip NPs exhibited significant urease enzyme inhibitory potential, with IC50 = 1.181 ± 0.02 µg/mL and 52.55 ± 2.3 µg/mL, compared to ciprofloxacin (IC50 = 82.95 ± 1.62 µg/mL). MNPs also exhibited significant antibacterial activity against selected bacterial strains.

  16. Synthesis, structures and urease inhibitory activity of cobalt(III) complexes with Schiff bases.

    Science.gov (United States)

    Jing, Changling; Wang, Cunfang; Yan, Kai; Zhao, Kedong; Sheng, Guihua; Qu, Dan; Niu, Fang; Zhu, Hailiang; You, Zhonglu

    2016-01-15

    A series of new cobalt(III) complexes were prepared. They are [CoL(1)(py)3]·NO3 (1), [CoL(2)(bipy)(N3)]·CH3OH (2), [CoL(3)(HL(3))(N3)]·NO3 (3), and [CoL(4)(MeOH)(N3)] (4), where L(1), L(2), L(3) and L(4) are the deprotonated form of N'-(2-hydroxy-5-methoxybenzylidene)-3-methylbenzohydrazide, N'-(2-hydroxybenzylidene)-3-hydroxylbenzohydrazide, 2-[(2-dimethylaminoethylimino)methyl]-4-methylphenol, and N,N'-bis(5-methylsalicylidene)-o-phenylenediamine, respectively, py is pyridine, and bipy is 2,2'-bipyridine. The complexes were characterized by infrared and UV-Vis spectra, and single crystal X-ray diffraction. The Co atoms in the complexes are in octahedral coordination. Complexes 1 and 4 show effective urease inhibitory activities, with IC50 values of 4.27 and 0.35 μmol L(-1), respectively. Complex 2 has medium activity against urease, with IC50 value of 68.7 μmol L(-1). While complex 3 has no activity against urease. Molecular docking study of the complexes with Helicobacter pylori urease was performed.

  17. Synthesis and in vitro acetylcholinesterase and butyrylcholinesterase inhibitory potential of hydrazide based Schiff bases.

    Science.gov (United States)

    Rahim, Fazal; Ullah, Hayat; Taha, Muhammad; Wadood, Abdul; Javed, Muhammad Tariq; Rehman, Wajid; Nawaz, Mohsan; Ashraf, Muhammad; Ali, Muhammad; Sajid, Muhammad; Ali, Farman; Khan, Muhammad Naseem; Khan, Khalid Mohammed

    2016-10-01

    To discover multifunctional agents for the treatment of Alzheimer's disease, a series of hydrazide based Schiff bases were designed and synthesized based on multitarget-directed strategy. We have synthesized twenty-eight analogs of hydrazide based Schiff bases, characterized by various spectroscopic techniques and evaluated in vitro for acetylcholinesterase and butyrylcholinesterase inhibition. All compounds showed varied degree of acetylcholinesterase and butyrylcholinesterase inhibition when compared with standard Eserine. Among the series, compounds 10, 3 and 24 having IC50 values 4.12±0.01, 8.12±0.01 and 8.41±0.06μM respectively showed potent acetylcholinesterase inhibition when compared with Eserine (IC50=0.85±0.0001μM). Three compounds 13, 24 and 3 having IC50 values 6.51±0.01, 9.22±0.07 and 37.82±0.14μM respectively showed potent butyrylcholinesterase inhibition by comparing with eserine (IC50=0.04±0.0001μM). The remaining compounds also exhibited moderate to weak inhibitory potential. Structure activity relationship has been established. Through molecular docking studies the binding interaction was confirmed.

  18. Design, synthesis, and AChE inhibitory activity of new benzothiazole-piperazines.

    Science.gov (United States)

    Demir Özkay, Ümide; Can, Özgür Devrim; Sağlık, Begüm Nurpelin; Acar Çevik, Ulviye; Levent, Serkan; Özkay, Yusuf; Ilgın, Sinem; Atlı, Özlem

    2016-11-15

    In the current study, 14 new benzothiazole-piperazine compounds were designed to meet the structural requirements of acetylcholine esterase (AChE) inhibitors. The target compounds were synthesised in three steps. Structures of the newly synthesised compounds (7-20) were confirmed using IR, (1)H NMR, (13)C NMR, and HRMS methods. The inhibitory potential of the compounds on AChE (E.C.3.1.1.7, from electric eel) was then investigated. Among the compounds, 19 and 20 showed very good activity on AChE enzyme. Kinetics studies were performed to observe the effects of the most active compounds on the substrate-enzyme relationship. Cytotoxicity studies, genotoxicity studies, and theoretical calculation of pharmacokinetics properties were also carried out. The compounds 19 and 20 were found to be nontoxic in both of the toxicity assays. A good pharmacokinetics profile was predicted for the synthesised compounds. Molecular docking studies were performed for the most active compounds, 19 and 20, and interaction modes with enzyme active sites were determined. Docking studies indicated a strong interaction between the active sites of AChE enzyme and the analysed compounds.

  19. Synthesis and inhibitory properties of some carbamates on carbonic anhydrase and acetylcholine esterase.

    Science.gov (United States)

    Yılmaz, Süleyman; Akbaba, Yusuf; Özgeriş, Bünyamin; Köse, Leyla Polat; Göksu, Süleyman; Gülçin, İlhami; Alwasel, Saleh H; Supuran, Claudiu T

    2016-12-01

    A series of carbamate derivatives were synthesized and their carbonic anhydrase I and II isoenzymes and acetylcholinesterase enzyme (AChE) inhibitory effects were investigated. All carbamates were synthesized from the corresponding carboxylic acids via the Curtius reactions of the acids with diphenyl phosphoryl azide followed by addition of benzyl alcohol. The carbamates were determined to be very good inhibitors against for AChE and hCA I, and II isoenzymes. AChE inhibition was determined in the range 0.209-0.291 nM. On the other hand, tacrine, which is used in the treatment of Alzheimer's disease possessed lower inhibition effect (Ki: 0.398 nM). Also, hCA I and II isoenzymes were effectively inhibited by the carbamates, with inhibition constants (Ki) in the range of 4.49-5.61 nM for hCA I, and 4.94-7.66 nM for hCA II, respectively. Acetazolamide, which was clinically used carbonic anhydrase (CA) inhibitor demonstrated Ki values of 281.33 nM for hCA I and 9.07 nM for hCA II. The results clearly showed that AChE and both CA isoenzymes were effectively inhibited by carbamates at the low nanomolar levels.

  20. Synthesis, anti-inflammatory, analgesic, COX1/2-inhibitory activity, and molecular docking studies of hybrid pyrazole analogues

    Directory of Open Access Journals (Sweden)

    Alam MJ

    2016-10-01

    Full Text Available Md Jahangir Alam,1 Ozair Alam,1 Suroor Ahmad Khan,1 Mohd Javed Naim,1 Mohammad Islamuddin,2 Girdhar Singh Deora3 1Department of Pharmaceutical Chemistry, Faculty of Pharmacy, 2Parasite Immunology Laboratory, Department of Biotechnology, Faculty of Science, Jamia Hamdard, New Delhi, 3Institute of Life Sciences, University of Hyderabad, Hyderabad, India Abstract: This article reports on the design, synthesis, and pharmacological activity of a new series of hybrid pyrazole analogues: 5a–5u. Among the series 5a–5u, the compounds 5u and 5s exhibited potent anti-inflammatory activity of 80.63% and 78.09% and inhibition of 80.87% and 76.56% compared with the standard drug ibuprofen, which showed 81.32% and 79.23% inhibition after 3 and 4 hours, respectively. On the basis of in vivo studies, 12 compounds were selected for assessment of their in vitro inhibitory action against COX1/2 and TNFα. The compounds 5u and 5s showed high COX2-inhibitory activity, with half-maximal inhibitory concentrations of 1.79 and 2.51 µM and selectivity index values of 72.73 and 65.75, respectively, comparable to celecoxib (selectivity index =78.06. These selected compounds were also tested for TNFα, cytotoxicity, and ulcerogenicity. Docking studies were also carried out to determine possible interactions of the potent compounds (5u and 5s, which also showed high docking scores of -12.907 and -12.24 compared to celecoxib, with a -9.924 docking score. These selective COX2 inhibitors were docked into the active site of COX2, and showed the same orientation and binding mode to that of celecoxib (selective COX2 inhibitor. Docking studies also showed that the SO2NH2 of 5u and 5s is inserted deep inside the selective pocket of the COX2-active site and formed a hydrogen-bond interaction with His90, Arg513, Phe518, Ser353, Gln192, and Ile517, which was further validated by superimposed docked pose with celecoxib. Keywords: anti-inflammatory activity, analgesic activity

  1. Inhibitory effects in the side reactions occurring during the enzymic synthesis of amoxicillin: p-hydroxyphenylglycine methyl ester and amoxicillin hydrolysis.

    Science.gov (United States)

    Gonçalves, Luciana R B; Fernandez-Lafuente, Roberto; Guisan, Jose M; Giordano, Raquel L C; Giordano, Roberto C

    2003-08-01

    Penicillin G acylase immobilized on glyoxyl-agarose is used to catalyse the reaction between p -hydroxyphenylglycine methyl ester (POHPGME) and 6-aminopenicillanic acid (6-APA). Inhibitory effects affecting the side reactions that occur during the synthesis of amoxicillin have been reported and need to be considered when proposing a kinetic model for the enzymic synthesis. In this work, we present a semi-empirical kinetic model that successively includes different inhibitory effects in the rate equations. The model performance was always compared with experimental data on amoxicillin synthesis. Enzyme load and stirring rate were chosen to prevent diffusional effects. Our results indicate that POHPGME and amoxicillin were competitive inhibitors of the hydrolysis of amoxicillin and POHPGME, respectively. 6-APA was a competitive inhibitor of the hydrolysis of amoxicillin. POHPG was a competitive inhibitor and methanol a non-competitive inhibitor of the hydrolysis of both ester and antibiotic, but the action of methanol was only noticeable at very high concentrations. Adding inhibitory effects to the kinetic model led to a significant increase in the accuracy of the simulations of the overall process of synthesis.

  2. Synthesis of high intensity green emitting (Ba,Sr)SiO4:Eu2+ phosphors through cellulose assisted liquid phase precursor process

    Science.gov (United States)

    Humayoun, Usama Bin; Song, Young-Hyun; Lee, MinJi; Masato, Kakihana; Abe, Hiroshi; Toda, Kenji; Sato, Yasushi; Masaki, Takaki; Yoon, Dae-Ho

    2016-01-01

    Green emitting phosphor (Ba1-x,Sr1-x)SiO4:2xEu2+, x = 0.03, 0.05, 0.1, and 0.15 were synthesized through a Liquid Phase Precursor Process (LPP). Liquid phase precursor method is reported to result in phosphors with markedly increased emission intensities compared to other synthesis methods. Here microcrystalline cellulose (MCC) and hydroxypropyl cellulose (HPC) templates were studied to achieve high efficiency green phosphors. The phase formation was investigated by XRD analysis which showed the conformation of the Ba2SiO4 (JCPDS card number 761631) phase. The obtained samples exhibited broad excitation spectra with maximum at 430 nm and a green emission centered around 520 nm. An optimized dopant concentration was selected and the effect of two different types of cellulose, i.e. MCC and HPC templates on the emission properties was considered. It was found that the samples synthesized using HPC and fired at 1050 °C under a reducing atmosphere, showed a high intensity of almost 2 times that of the MCC sample. Further experiments were conducted by varying viscosity, particle weight, and molecular weight of the HPC template. It was found that the green emission from the (Ba,Sr)SiO4:Eu2+ increased with the increase in viscosity and molecular weight of the template.

  3. Microwave-Assisted Combustion Synthesis of Nano Iron Oxide/Iron-Coated Activated Carbon, Anthracite, Cellulose Fiber, and Silica, with Arsenic Adsorption Studies

    Directory of Open Access Journals (Sweden)

    Mallikarjuna N. Nadagouda

    2011-01-01

    Full Text Available Combustion synthesis of iron oxide/iron coated carbons such as activated carbon, anthracite, cellulose fiber, and silica is described. The reactions were carried out in alumina crucibles using a Panasonic kitchen microwave with inverter technology, and the reaction process was completed within a few minutes. The method used no additional fuel and nitrate, which is present in the precursor itself, to drive the reaction. The obtained samples were then characterized with X-ray mapping, scanning electron microscopy (SEM, energy dispersive X-ray analysis (EDS, selected area diffraction pattern (SAED, transmission electron microscopy (TEM, X-ray diffraction (XRD, and inductively coupled plasma (ICP spectroscopy. The size of the iron oxide/iron nanoparticle-coated activated carbon, anthracite, cellulose fiber, and silica samples were found to be in the nano range (50–400 nm. The iron oxide/iron nanoparticles mostly crystallized into cubic symmetry which was confirmed by SAED. The XRD pattern indicated that iron oxide/iron nano particles existed in four major phases. That is, γ-Fe2O3, α-Fe2O3, Fe3O4, and Fe. These iron-coated activated carbon, anthracite, cellulose fiber, and silica samples were tested for arsenic adsorption through batch experiments, revealing that few samples had significant arsenic adsorption.

  4. Synthesis and glycosidase inhibitory activity of new hexa-substituted C8-glycomimetics

    Directory of Open Access Journals (Sweden)

    Prangé Thierry

    2005-10-01

    Full Text Available Text abstract Background Glycosidases are involved in several metabolic pathways and the development of inhibitors is an important challenge towards the treatment of diseases, such as diabetes, cancer and viral infections including AIDS. Thus, inhibition of intestinal α-glucosidases can be used to treat diabetes through the lowering of blood glucose levels, and α-glucosidase inhibitors are being marketed against type 2 (non-insulinodependent mellitus diabetes (i.e.: Glyset® or Diastabol®, Basen® and Glucor® or Precose®. Results In that context, new C8-carbasugars and related aminocyclitols have been targeted in order to study the effect of the enhanced flexibility and of the new spatial distribution displayed by these structures on their adaptability in the active site of the enzymes. The synthesis of these new C8-glycomimetics is described from enantiomerically pure C2-symmetrical polyhydroxylated cyclooctenes. Their obtention notably involved a syn-dihydroxylation, and more extended functionalization through formation of a cis-cyclic sulfate followed by amination and subsequent reductive amination. This strategy involving the nucleophilic opening of a cis-cyclic sulfate by sodium azide is to our knowledge the first example in C8-series. It revealead to be an efficient alternative to the nucleoplilic opening of an epoxide moiety which proved unsuccessful in this particular case, due to the hindered conformation of such epoxides as demonstrated by X-ray cristallographic analysis. Conclusion The biological activity of the synthesized glycomimetics has been evaluated towards 24 commercially available glycosidases. The weak observed activities can probably be related to the spatial disposition of the hydroxy and amino groups which depart too much from that realized in glycomimetics such as valiolamine, voglibose and valienamine. Nevertheless, the synthetic strategy described here is efficient and general, and could be extended to increase

  5. CelR, an Ortholog of the Diguanylate Cyclase PleD of Caulobacter, Regulates Cellulose Synthesis in Agrobacterium tumefaciens

    OpenAIRE

    Barnhart, D. Michael; Su, Shengchang; Baccaro, Brenna E.; Banta, Lois M.; Farrand, Stephen K.

    2013-01-01

    Cellulose fibrils play a role in attachment of Agrobacterium tumefaciens to its plant host. While the genes for cellulose biosynthesis in the bacterium have been identified, little is known concerning the regulation of the process. The signal molecule cyclic di-GMP (c-di-GMP) has been linked to the regulation of exopolysaccharide biosynthesis in many bacterial species, including A. tumefaciens. In this study, we identified two putative diguanylate cyclase genes, celR (atu1297) and atu1060, th...

  6. Inhibitory effect of p-coumaric acid by Rhodiola sachalinensis on melanin synthesis in B16F10 cells.

    Science.gov (United States)

    Park, So-Hee; Kim, Dong-Seok; Park, Seo-Hyoung; Shin, Jung-Won; Youn, Sang-Woong; Park, Kyoung-Chan

    2008-04-01

    Rhodiola has been widely used in traditional Asian medicine. In this study, we tested the hypopigmentation effects of R. sachalinensis and its active compounds including catechin, chlorogenic acid, p-coumaric acid, and p-tyrosol. Results have shown that only p-coumaric acid inhibits melanin synthesis in B16F10 cells. However, p-coumaric acid did not inhibit tyrosinase activity when L-DOPA was used as a substrate. Instead, p-coumaric acid inhibited tyrosinase activity when L-tyrosine was used as a substrate. We further analyzed the changes of cAMP responsive element binding protein (CREB) phosphorylation and tyrosinase gene expression. The results indicate that p-coumaric acid does not affect CREB phosphorylation or tyrosinase protein production. In turn, these findings demonstrate that p-coumaric acid has no effect on the upstream regulation of tyrosinase gene expression, although p-coumaric acid showed a significant inhibitory effect on melanogenesis. Because p-coumaric acid showed different effects on tyrosinase activity according to different substrates, we tested whether tyrosinase can utilize p-coumaric acid as a substrate. Our findings revealed that competitive inhibition occurs between p-coumaric acid and tyrosine. Consequently, this finding could be a primary mechanism for the hypopigmenting action of p-coumaric acid.

  7. The copolimeryzation synthesis and swelling capacity of cellulose-poly superabsorbent (acrylic acid-co-acrylamide) based on rice straw

    Science.gov (United States)

    Helmiyati; Fitriyani, A.; Meyanti, F.

    2017-04-01

    A superabsorbent has been synthesized by copolymerization of rice straw cellulose as the back bone with the composition of 0.724 mol/L acrylamide and 1.429 mol/L acrylic acid as the monomers, 2.32 mmol/L N, N‧-methylene-bis-acrylamide as the crosslinker, and 7.94 mmol/L potassium persulfate as the initiator. The rendement of cellulose obtained from rice straw isolation is 33.55% with the size of 34.06 nm nanocrystalline cellulose, obtained from XRD diffraction pattern. The copolymerization results in the spectrum characterization of Cellulose-Poly superabsorbent (AA-co-AM) with FTIR shows OH stretching vibration, NH and C=O stretching of monomer acrylic acid and acrylamide at wave number about 3343 cm-1 and 1600 cm-1. The surface morphology analyzed with SEM shows the superabsorbent has rough surface morphology compared to acrylic acid-acrylamide copolymer. The results of grafting efficiency increases with the increasing amount of the reacted monomer. The characterization of result shows that the grafting process of acrylic acid-acrylamide on cellulose has been formed. The swelling capacity of superabsorbent in water is 691.18 g/g, and 765.58 g/g in urea. This result is quite satisfactory and can be applied for slow release superabsorbent.

  8. Synthesis and characterization of polyvinyl alcohol/cellulose cryogels and their testing as carriers for a bioactive component

    Energy Technology Data Exchange (ETDEWEB)

    Paduraru, Oana Maria; Ciolacu, Diana; Darie, Raluca Nicoleta; Vasile, Cornelia, E-mail: cvasile@icmpp.ro

    2012-12-01

    Novel physically cross-linked cryogels containing polyvinyl alcohol (PVA) and various amounts of microcrystalline cellulose were obtained by freezing/thawing technique. The main goal of this study was to improve the properties and the performances of the pure PVA cryogels. The morphological aspects of the cryogels were studied by scanning electron microscopy (SEM). The Fourier transform infrared spectroscopy (FT-IR) was used to reveal the presence of the interactions between the two polymers. Changes in crystallinity of the samples were confirmed by X-ray diffraction (XRD) and by FT-IR spectroscopy. The modification of the thermal behavior induced by cellulose was studied by thermogravimetry. Rheological analysis revealed higher values of storage modulus (G Prime ) for the cryogels containing higher amounts of cellulose. The degree and rate of swelling were controlled by the presence of the natural polymer in the network. The potential application as bioactive compound carriers was tested, using vanillin as an active agent. Highlights: Black-Right-Pointing-Pointer Novel PVA/microcrystalline cellulose cryogels were obtained by freezing/thawing. Black-Right-Pointing-Pointer The main advantage of this technique is that no chemical crosslinker is being used. Black-Right-Pointing-Pointer The presence of cellulose improves the swelling properties and the cryogels' strength. Black-Right-Pointing-Pointer The potential application as carriers for bioactive components was tested.

  9. 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.

  10. In vitro synthesis of cellulose microfibrils by a membrane protein from protoplasts of the non-vascular plant Physcomitrella patens.

    Science.gov (United States)

    Cho, Sung Hyun; Du, Juan; Sines, Ian; Poosarla, Venkata Giridhar; Vepachedu, Venkata; Kafle, Kabindra; Park, Yong Bum; Kim, Seong H; Kumar, Manish; Nixon, B Tracy

    2015-09-01

    Plant cellulose synthases (CesAs) form a family of membrane proteins that are associated with hexagonal structures in the plasma membrane called CesA complexes (CSCs). It has been difficult to purify plant CesA proteins for biochemical and structural studies. We describe CesA activity in a membrane protein preparation isolated from protoplasts of Physcomitrella patens overexpressing haemagglutinin (HA)-tagged PpCesA5. Incubating the membrane preparation with UDP-glucose predominantly produced cellulose. Negative-stain EM revealed microfibrils. Cellulase bound to and degraded these microfibrils. Vibrational sum frequency generation (SFG) spectroscopic analysis detected the presence of crystalline cellulose in the microfibrils. Putative CesA proteins were frequently observed attached to the microfibril ends. Combined cross-linking and gradient centrifugation showed bundles of cellulose microfibrils with larger particle aggregates, possibly CSCs. These results suggest that P. patens is a useful model system for biochemical and structural characterization of plant CSCs and their components.

  11. Aqueous-Phase Synthesis of Silver Nanodiscs and Nanorods in Methyl Cellulose Matrix: Photophysical Study and Simulation of UV–Vis Extinction Spectra Using DDA Method

    Directory of Open Access Journals (Sweden)

    Sarkar Priyanka

    2010-01-01

    Full Text Available Abstract We present a very simple and effective way for the synthesis of tunable coloured silver sols having different morphologies. The procedure is based on the seed-mediated growth approach where methyl cellulose (MC has been used as soft-template in the growth solution. Nanostructures of varying morphologies as well as colour of the silver sols are controlled by altering the concentration of citrate in the growth solution. Similar to the polymers in the solution, citrate ions also dynamically adsorbed on the growing silver nanoparticles and promote one (1-D and two-dimensional (2-D growth of nanoparticles. Silver nanostructures are characterized using UV–vis and HR-TEM spectroscopic study. Simulation of the UV–vis extinction spectra of our synthesized silver nanostructures has been carried out using discrete dipole approximation (DDA method.

  12. Aqueous-Phase Synthesis of Silver Nanodiscs and Nanorods in Methyl Cellulose Matrix: Photophysical Study and Simulation of UV-Vis Extinction Spectra Using DDA Method.

    Science.gov (United States)

    Sarkar, Priyanka; Bhui, Dipak Kumar; Bar, Harekrishna; Sahoo, Gobinda Prasad; Samanta, Sadhan; Pyne, Santanu; Misra, Ajay

    2010-07-18

    We present a very simple and effective way for the synthesis of tunable coloured silver sols having different morphologies. The procedure is based on the seed-mediated growth approach where methyl cellulose (MC) has been used as soft-template in the growth solution. Nanostructures of varying morphologies as well as colour of the silver sols are controlled by altering the concentration of citrate in the growth solution. Similar to the polymers in the solution, citrate ions also dynamically adsorbed on the growing silver nanoparticles and promote one (1-D) and two-dimensional (2-D) growth of nanoparticles. Silver nanostructures are characterized using UV-vis and HR-TEM spectroscopic study. Simulation of the UV-vis extinction spectra of our synthesized silver nanostructures has been carried out using discrete dipole approximation (DDA) method.

  13. Anatase TiO2/cellulose hybrid paper: Synthesis, characterizations, and photocatalytic activity for degradation of indigo carmine dye

    Science.gov (United States)

    Jiao, Yue; Wan, Caichao; Li, Jian

    We report a facile easy method to deposit anatase titania (TiO2) on cellulose paper. The anatase TiO2/cellulose paper (ATCP) was characterized by scanning electron microscopy, transmission electron microscope, energy dispersive X-ray spectrometer, X-ray diffraction, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and thermogravimetric analysis. This hybrid paper with the anatase TiO2 content of around 13.86wt.% can serve as an eco-friendly flexible photocatalyst, which can rapidly degrade blue indigo carmine dye into a colorless solution within 30min under UV radiation. Moreover, compared to commercially available TiO2 P25 and anatase TiO2 powder, a faster decomposition rate of indigo carmine dye was acquired when using ATCP. These results suggest that this hybrid paper might be useful in the treatment of organic dye wastewater.

  14. Direct synthesis of sorbitol and glycerol from cellulose over ionic Ru/magnetite nanoparticles in the absence of external hydrogen.

    Science.gov (United States)

    Negoi, Alina; Trotus, Ioan Teodor; Mamula Steiner, Olimpia; Tudorache, Madalina; Kuncser, Victor; Macovei, Dan; Parvulescu, Vasile I; Coman, Simona M

    2013-11-01

    A sweet catalyst: A catalyst formed of Ru/functionalized silica-coated magnetite nanoparticles is highly efficient in the one-pot production of sorbitol and glycerol, starting from cellulose and in the absence of an external hydrogen source. The ease of recoverability of the catalyst from the solid residues, and its reuse without loss of activity or selectivity for several runs, is an important green element of the process.

  15. Effects of reaction conditions on cellulose structures synthesized in vitro by bacterial cellulose synthases.

    Science.gov (United States)

    Penttilä, Paavo A; Sugiyama, Junji; Imai, Tomoya

    2016-01-20

    Cellulose was synthesized by cellulose synthases extracted from the Komagataeibacter xylinus (formerly known as Gluconacetobacter xylinus). The effects of temperature and centrifugation of the reaction solution on the synthesis products were investigated. Cellulose with number-average degree of polymerization (DPn) roughly in the range 60-80 and cellulose II crystal structure was produced under all conditions. The amount of cellulose varied with temperature and centrifugation, and the centrifugation at 2000 × g also slightly reduced the DPn. Cellulose production was maximal around the temperature 35 °C and without centrifugation. At higher temperatures and during centrifugation at 2000 × g the proteins started to denature, causing differences also in the morphology of the cellulosic aggregates, as seen with electron microscopy. These observations serve as a basis for discussions about the factors affecting the structure formation and chain length of in vitro synthesized cellulose.

  16. Bioplastic production from cellulose of oil palm empty fruit bunch

    Science.gov (United States)

    Isroi; Cifriadi, A.; Panji, T.; Wibowo, Nendyo A.; Syamsu, K.

    2017-05-01

    Empty fruit bunch is available abundantly in Indonesia as side product of CPO production. EFB production in Indonesia reached 28.65 million tons in 2015. EFB consist of 36.67% cellulose, 13.50% hemicellulose and 31.16% lignin. By calculation, potential cellulose from EFB is 11.50 million tons. Cellulose could be utilized as source for bioplastic production. This research aims to develop bioplastic production based on cellulose from EFB and to increase added value of EFB. Cellulose fiber has no plastic properties. Molecular modification of cellulose, composite with plasticizer and compatibilizer is a key success for utilization of cellulose for bioplastic. Main steps of bioplastic production from EFB are: 1) isolation and purification of cellulose, 2) cellulose modification and 3) synthesis of bioplastic. Cellulose was isolated by sodium hydroxide methods and bleached using sodium hypochlorite. Purity of obtained cellulose was 97%. Cellulose yield could reach 30% depend on cellulose content of EFB. Cellulose side chain was oxidized to reduce hydroxyl group and increase the carboxyl group. Bioplastic synthesis used glycerol as plasticizer and cassava starch as matrix. This research was successfully producing bioplastic sheet by casting method. In future prospects, bioplastic from EFB cellulose can be developed as plastic bag and food packaging.

  17. Discovery of pyrido[3,4-g]quinazoline derivatives as CMGC family protein kinase inhibitors: Design, synthesis, inhibitory potency and X-ray co-crystal structure.

    Science.gov (United States)

    Esvan, Yannick J; Zeinyeh, Wael; Boibessot, Thibaut; Nauton, Lionel; Théry, Vincent; Knapp, Stefan; Chaikuad, Apirat; Loaëc, Nadège; Meijer, Laurent; Anizon, Fabrice; Giraud, Francis; Moreau, Pascale

    2016-08-08

    The design and synthesis of new pyrido[3,4-g]quinazoline derivatives is described as well as their protein kinase inhibitory potencies toward five CMGC family members (CDK5, CK1, GSK3, CLK1 and DYRK1A). The interest for this original tricyclic heteroaromatic scaffold as modulators of CLK1/DYRK1A activity was validated by nanomolar potencies (compounds 12 and 13). CLK1 co-crystal structures with two inhibitors revealed the binding mode of these compounds within the ATP-binding pocket.

  18. Design and synthesis of a vialinin A analog with a potent inhibitory activity of TNF-α production and its transformation into a couple of bioprobes.

    Science.gov (United States)

    Ye, Yue Qi; Onose, Jun-ichi; Abe, Naoki; Koshino, Hiroyuki; Takahashi, Shunya

    2012-04-01

    Vialinin A (1) is an extremely potent inhibitor against tumor necrosis factor (TNF)-α production in rat basophilic leukemia (RBL-2H3) cells. This Letter describes the design and synthesis of its advanced analog, 5',6'-dimethyl-1,1':4'1″-terphenyl-2',3',4,4″-tetraol (2) with a comparable inhibitory activity (IC(50)=0.02 nM) to that of 1. The synthesis involved double Suzuki-Miyaura coupling as a key step, and required only five steps from commercially available 3,4-dimethylphenol. For identification of the target molecule, fluorescent and biotinylated derivatives of 2 were prepared through a 'click' coupling process.

  19. 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...

  20. Synthesis and characterization of cellulose-functionalized 3,4-dihydroxyphenylalanine(dopamine)/silica-gold nanomaterials by sol-gel process.

    Science.gov (United States)

    Ramesh, Sivalingam; Kim, Joo-Hyung

    2012-10-01

    Cellulose-metal oxide nanomaterials were developed the technologies to manipulate self-assembly and multi-functionallity, of new technologies to the point where industry can produce advanced and cost-competitive cellulose and lignocellulose-based materials. The present investigation focused on cellulose-silica and cellulose functionalized 3,4-dihydroxy phenyl alanine(dopamine) silica/gold nanomaterials by in-situ sol-gel process. The tetraethoxysilane (TEOS) and gold precursors such as tetrachloroauricacid (HAuCl4) and γ- aminopropyltriethoxysilane (γ-APTES) as coupling agent were used for sol-gel crosslinking process. The chemical and morphological properties of cellulose/silica and cellulose /silica-gold nanomaterials via covalent crosslinking hybrids were investigated with FTIR, XRD, SEM and TEM analysis. The results show that cellulose/silica and cellulose functionalized dopamine-silica/gold hybrids form new macromolecular structures in the size of 20 nm.

  1. The experimental herbicide CGA 325'615 inhibits synthesis of crystalline cellulose and causes accumulation of non-crystalline beta-1,4-glucan associated with CesA protein.

    Science.gov (United States)

    Peng, L; Xiang, F; Roberts, E; Kawagoe, Y; Greve, L C; Kreuz, K; Delmer, D P

    2001-07-01

    Developing cotton (Gossypium hirsutum) fibers, cultured in vitro with their associated ovules, were used to compare the effects of two herbicides that inhibit cellulose synthesis: 2,6-dichlorobenzonitrile (DCB) and an experimental thiatriazine-based herbicide, CGA 325'615. CGA 325'615 in nanomolar concentrations or DCB in micromolar concentrations causes inhibition of synthesis of crystalline cellulose. Unlike DCB, CGA 325'615 also causes concomitant accumulation of non-crystalline beta-1,4-glucan that can be at least partially solubilized from fiber walls with ammonium oxalate. The unusual solubility of this accumulated glucan may be explained by its strong association with protein. Treatment of the glucan fraction with protease changes its size distribution and leads to precipitation of the glucan. Treatment of the glucan fraction with cellulase digests the glucan and also releases protein that has been characterized as GhCesA-1 and GhCesA-2--proteins that are believed to represent the catalytic subunit of cellulose synthase. The fact that cellulase treatment is required to release this protein indicates an extremely tight association of the glucan with the CesA proteins. In addition, CGA 325'615, but not DCB, also causes accumulation of CesA protein and a membrane-associated cellulase in the membrane fraction of fibers. In addition to the effects of CGA 325'615 on levels of both of these proteins, the level of both also shows coordinate regulation during fiber development, further suggesting they are both important for cellulose synthesis. The accumulation of non-crystalline glucan caused by CGA 325'615 mimics the phenotype of the cellulose-deficient rsw1 mutant of Arabidopsis that also accumulates an apparently similar glucan (T. Arioli, L. Peng, A.S. Betzner, J. Burn, W. Wittke, W. Herth, C. Camilleri, H. Hofte, J. Plazinski, R. Birch et al. [1998] Science 279: 717).

  2. Radiation synthesis and performance of novel cellulose-based microsphere adsorbents for efficient removal of boron (III).

    Science.gov (United States)

    Liu, Siqi; Xu, Min; Yu, Tianlin; Han, Dong; Peng, Jing; Li, Jiuqiang; Zhai, Maolin

    2017-10-15

    A novel cellulose-based microsphere containing glucamine groups, referred as CVN, was successfully synthesized by radiation-induced graft polymerization of 4-vinylbenzyl chloride onto cellulose microspheres and subsequent functionalization with N-methyl-d-glucamine. The adsorption by CVN for boron (III) from aqueous solutions was evaluated systematically by batch adsorption technique. Langmuir models could fit well with the adsorption behavior of CVN. The CVN adsorbents exhibited a high adsorption capacity up to 12.4mgg(-1) towards boron (III) over the wide pH range of 5-8. After the addition of chloride salts, the boron uptake of CVN was enhanced that was attributed to the compensation of the surface charge generated by boron (III) adsorption leading to favor the adsorption. At high concentrations of salts, the ionic strength and different salts have no effect on the adsorption of boron(III). This work provides a new sustainable, cost effective material as a promising specific adsorbent for the removal of boron (III) from saline solutions. Copyright © 2017 Elsevier Ltd. All rights reserved.

  3. Synthesis and characterization of carboxymethyl cellulose/organic montmorillonite nanocomposites and its adsorption behavior for Congo Red dye

    Directory of Open Access Journals (Sweden)

    Min-min WANG

    2013-07-01

    Full Text Available A series of carboxymethyl cellulose/organic montmorillonite (CMC/OMMT nanocomposites with different weight ratios of carboxymethyl cellulose (CMC to organic montmorillonite (OMMT were synthesized under different conditions. The nanocomposites were characterized by the Fourier transform infrared (FT-IR spectrophotometer, X-ray diffraction (XRD method, transmission electron microscope (TEM, scanning electron microscope (SEM, and thermal gravimetric (TG analysis. The results showed that the introduction of CMC may have different influences on the physico-chemical properties of OMMT and intercalated-exfoliated nanostructures were formed in the nanocomposites. The effects of different reaction conditions on the adsorption capacity of samples for Congo Red (CR dye were investigated by controlling the amount of hexadecyl trimethyl ammonium bromide (CTAB, the weight ratio of CMC to OMMT, the reaction time, and the reaction temperature. Results from the adsorption experiment showed that the adsorption capacity of the nanocomposites can reach 171.37 mg/g, with the amount of CTAB being 1.0 cation exchange capacity (CEC of MMT, the weight ratio of CMC to OMMT being 1?1, the reaction time being 6 h, and the reaction temperature being 60℃. The CMC/OMMT nanocomposite can be used as a potential adsorbent to remove CR dye from an aqueous solution.

  4. Synthesis, crystal structures, fluorescence and xanthine oxidase inhibitory activity of pyrazole-based 1,3,4-oxadiazole derivatives

    Science.gov (United States)

    Qi, De-Qiang; Yu, Chuan-Ming; You, Jin-Zong; Yang, Guang-Hui; Wang, Xue-Jie; Zhang, Yi-Ping

    2015-11-01

    A series of pyrazole-based 1,3,4-oxadiazole derivatives were rationally designed and synthesized in good yields by following a convenient route. All the newly synthesized molecules were fully characterized by IR, 1H NMR and elemental analysis. Eight compounds were structurally determined by single crystal X-ray diffraction analysis. The fluorescence properties of all the compounds were investigated in dimethyl sulfoxide media. In addition, these newly synthesized compounds were evaluated for in vitro inhibitory activity against commercial enzyme xanthine oxidase (XO) by measuring the formation of uric acid from xanthine. Among the compounds synthesized and tested, 3d and 3e were found to be moderate inhibitory activity against commercial XO with IC50 = 72.4 μM and 75.6 μM. The studies gave a new insight in further optimization of pyrazole-based 1,3,4-oxadiazole derivatives with excellent fluorescence properties and XO inhibitory activity.

  5. Synthesis, characterization, and debromination reactivity of cellulose-stabilized Pd/Fe nanoparticles for 2,2',4,4'-tretrabromodiphenyl ether

    Science.gov (United States)

    Huang, Guofu; Wang, Mianmian; Hu, Yongyou; Lv, Sihao; Li, Changfang

    2017-01-01

    In this study, two kinds of cellulose derivatives (polyanionic cellulose (PAC) and hydroxypropylmethyl cellulose (HPMC)) were selected as stabilizers of Pd/Fe nanoparticles (NPs) to investigate their influences on the debromination performances of 2,2',4,4'-tretrabromodiphenyl ether (BDE47). Field emission scanning electron microscope (FE-SEM) images revealed that the cellulose-stabilized Pd/Fe NPs were smaller and more uniform than the bare-Pd/Fe NPs. X-ray diffractometer (XRD) and X-ray photoelectron spectroscopy (XPS) results suggested that cellulose coatings found on Pd/Fe NPs surfaces featured some antioxidation abilities, which followed the order of HPMC soils. PMID:28355273

  6. Design and Synthesis of High-Affinity Dimeric Inhibitors Targeting the Interactions between Gephyrin and Inhibitory Neurotransmitter Receptors

    DEFF Research Database (Denmark)

    Maric, Hans-Michael; Kasaragod, Vikram Babu; Kedström, Linda Maria Haugaard

    2015-01-01

    Gephyrin is the central scaffolding protein for inhibitory neurotransmitter receptors in the brain. Here we describe the development of dimeric peptides that inhibit the interaction between gephyrin and these receptors, a process which is fundamental to numerous synaptic functions and diseases...

  7. Synthesis and characterization of methylcellulose from cellulose extracted from mango seeds for use as a mortar additive

    Directory of Open Access Journals (Sweden)

    Júlia G. Vieira

    2012-01-01

    Full Text Available Methylcellulose was produced from the fibers of Mangifera indica L. Ubá mango seeds. MCD and MCI methylcellulose samples were made by heterogeneous methylation, using dimethyl sulfate and iodomethane as alkylating agents, respectively. The materials produced were characterized for their thermal properties (DSC and TGA, crystallinity (XRD and Degree of Substitution (DS in the chemical route. The cellulose derivatives were employed as mortar additive in order to improve mortar workability and adhesion to the substrate. These properties were evaluated by means of the consistency index (CI and bond tensile strength (TS tests. The methylcellulose (MCD and MCI samples had CI increased by 27.75 and 71.54% and TS increased by 23.33 and 29.78%, respectively, in comparison to the reference sample. Therefore, the polymers can be used to produce adhesive mortars.

  8. Antitumor polycyclic acridines. 8.(1) Synthesis and telomerase-inhibitory activity of methylated pentacyclic acridinium salts.

    Science.gov (United States)

    Heald, Robert A; Modi, Chetna; Cookson, Jenny C; Hutchinson, Ian; Laughton, Charles A; Gowan, Sharon M; Kelland, Lloyd R; Stevens, Malcolm F G

    2002-01-31

    Two short routes to novel methylated pentacyclic quinoacridinium salts have been devised. New compounds display telomerase-inhibitory potency (quino[4,3,2-kl]acridinium methosulfate (12d, RHPS4, NSC 714187) has a higher selectivity for triplex and quadruplex DNA structures than the 3,6,8,11,13-pentamethyl analogue (12c, RHPS3, NSC 714186) and a low overall growth-inhibitory activity in the NCI 60 cell panel (mean GI(50) 13.18 microM); in addition, the activity profile of 12d does not COMPARE with agents of the topoisomerase II class. Compound 12d is soluble in water, stable in the pH range of 5-9, efficiently transported into tumor cells, and is currently the lead structure for further elaboration in this new class of telomerase inhibitor.

  9. Isolation and characterization of two cellulose morphology mutants of Gluconacetobacter hansenii ATCC23769 producing cellulose with lower crystallinity.

    Directory of Open Access Journals (Sweden)

    Ying Deng

    Full Text Available Gluconacetobacter hansenii, a Gram-negative bacterium, produces and secrets highly crystalline cellulose into growth medium, and has long been used as a model system for studying cellulose synthesis in higher plants. Cellulose synthesis involves the formation of β-1,4 glucan chains via the polymerization of glucose units by a multi-enzyme cellulose synthase complex (CSC. These glucan chains assemble into ordered structures including crystalline microfibrils. AcsA is the catalytic subunit of the cellulose synthase enzymes in the CSC, and AcsC is required for the secretion of cellulose. However, little is known about other proteins required for the assembly of crystalline cellulose. To address this question, we visually examined cellulose pellicles formed in growth media of 763 individual colonies of G. hansenii generated via Tn5 transposon insertion mutagenesis, and identified 85 that produced cellulose with altered morphologies. X-ray diffraction analysis of these 85 mutants identified two that produced cellulose with significantly lower crystallinity than wild type. The gene disrupted in one of these two mutants encoded a lysine decarboxylase and that in the other encoded an alanine racemase. Solid-state NMR analysis revealed that cellulose produced by these two mutants contained increased amounts of non-crystalline cellulose and monosaccharides associated with non-cellulosic polysaccharides as compared to the wild type. Monosaccharide analysis detected higher percentages of galactose and mannose in cellulose produced by both mutants. Field emission scanning electron microscopy showed that cellulose produced by the mutants was unevenly distributed, with some regions appearing to contain deposition of non-cellulosic polysaccharides; however, the width of the ribbon was comparable to that of normal cellulose. As both lysine decarboxylase and alanine racemase are required for the integrity of peptidoglycan, we propose a model for the role of

  10. A Facile Ionic Liquid Promoted Synthesis, Cholinesterase Inhibitory Activity and Molecular Modeling Study of Novel Highly Functionalized Spiropyrrolidines

    Directory of Open Access Journals (Sweden)

    Abdulrahman I. Almansour

    2015-01-01

    Full Text Available A series of novel dimethoxyindanone embedded spiropyrrolidines were synthesized in ionic liquid, [bmim]Br and were evaluated for their inhibitory activities towards cholinesterases. Among the spiropyrrolidines, compound 4f exhibited the most potent activity with an IC50 value of 1.57 µM against acethylcholinesterase (AChE. Molecular docking simulation for the most active compound was employed with the aim of disclosing its binding mechanism to the active site of AChE receptor.

  11. 细菌纤维素的合成与调控进展%Progress in synthesis and regulation of bacterial cellulose

    Institute of Scientific and Technical Information of China (English)

    李欣; 颜彩玲; 潘凌鸿; 黄建忠

    2011-01-01

    Bacterial cellulose (BC) was a kind of natural high purity biopolymer compared with the lignocellu-lose, the production and processing of BC was more convenient and environment-friendly, thus it made BC be a promising biomaterial. At present, Quconacetobacter was found to be the highest yield BC-producing strain. In this review, the synthesis and the regulation mechanism of Quconacetobacter BC, the genetical engineering methods and culture methods for higher BC production were discussed.%细菌纤维素是1种天然的高纯度生物多聚物,与木质纤维素相比,其生产和加工过程更为方便和环保,因此已成为1种极有潜力的生物材料.葡糖酸醋杆菌是目前已知的产纤维素能力最高的菌株.综述了葡糖酸醋杆菌的细菌纤维素合成和调控机制以及为提高产量所进行的基因工程手段和培养方法.

  12. Biotemplate synthesis of polyaniline@cellulose nanowhiskers/natural rubber nanocomposites with 3D hierarchical multiscale structure and improved electrical conductivity.

    Science.gov (United States)

    Wu, Xiaodong; Lu, Canhui; Xu, Haoyu; Zhang, Xinxing; Zhou, Zehang

    2014-12-10

    Development of novel and versatile strategies to construct conductive polymer composites with low percolation thresholds and high mechanical properties is of great importance. In this work, we report a facile and effective strategy to prepare polyaniline@cellulose nanowhiskers (PANI@CNs)/natural rubber (NR) nanocomposites with 3D hierarchical multiscale structure. Specifically, PANI was synthesized in situ on the surface of CNs biotemplate to form PANI@CNs nanohybrids with high aspect ratio and good dispersity. Then NR latex was introduced into PANI@CNs nanohybrids suspension to enable the self-assembly of PANI@CNs nanohybrids onto NR latex microspheres. During cocoagulation process, PANI@CNs nanohybrids selectively located in the interstitial space between NR microspheres and organized into a 3D hierarchical multiscale conductive network structure in NR matrix. The combination of the biotemplate synthesis of PANI and latex cocoagulation method significantly enhanced the electrical conductivity and mechanical properties of the NR-based nanocomposites simultaneously. The electrical conductivity of PANI@CNs/NR nanocomposites containing 5 phr PANI showed 11 orders of magnitude higher than that of the PANI/NR composites at the same loading fraction,; meanwhile, the percolation threshold was drastically decreased from 8.0 to 3.6 vol %.

  13. Synthesis of polymer electrolyte membranes from cellulose acetate/poly(ethylene oxide)/LiClO{sub 4} for lithium ion battery application

    Energy Technology Data Exchange (ETDEWEB)

    Nurhadini,, E-mail: nur-chem@yahoo.co.id; Arcana, I Made, E-mail: arcana@chem.itb.ac.id [Inorganic and Physical Chemistry Research Division, Faculty of Mathematics and Natural Sciences, Institiut Teknologi Bandung, Jalan Ganesha 10, Bandung 40132 (Indonesia)

    2015-09-30

    This study was conducted to determine the effect of cellulose acetate on poly(ethylene oxide)-LiClO{sub 4} membranes as the polymer electrolyte. Cellulose acetate is used as an additive to increase ionic conductivity and mechanical property of polymer electrolyte membranes. The increase the percentage of cellulose acetate in membranes do not directly effect on the ionic conductivity, and the highest ionic conductivity of membranes about 5,7 × 10{sup −4} S/cm was observed in SA/PEO/LiClO{sub 4} membrane with cellulose ratio of 10-25% (w/w). Cellulose acetate in membranes increases mechanical strength of polymer electrolyte membranes. Based on TGA analysis, this polymer electrolyte thermally is stable until 270 °C. The polymer electrolyte membrane prepared by blending the cellulose acetate, poly(ethylene oxide), and lithium chlorate could be potentially used as a polymer electrolyte for lithium ion battery application.

  14. Synthesis of polymer electrolyte membranes from cellulose acetate/poly(ethylene oxide)/LiClO4 for lithium ion battery application

    Science.gov (United States)

    Nurhadini, Arcana, I. Made

    2015-09-01

    This study was conducted to determine the effect of cellulose acetate on poly(ethylene oxide)-LiClO4 membranes as the polymer electrolyte. Cellulose acetate is used as an additive to increase ionic conductivity and mechanical property of polymer electrolyte membranes. The increase the percentage of cellulose acetate in membranes do not directly effect on the ionic conductivity, and the highest ionic conductivity of membranes about 5,7 × 10-4 S/cm was observed in SA/PEO/LiClO4 membrane with cellulose ratio of 10-25% (w/w). Cellulose acetate in membranes increases mechanical strength of polymer electrolyte membranes. Based on TGA analysis, this polymer electrolyte thermally is stable until 270 °C. The polymer electrolyte membrane prepared by blending the cellulose acetate, poly(ethylene oxide), and lithium chlorate could be potentially used as a polymer electrolyte for lithium ion battery application.

  15. Synthesis of cellulose-based superabsorbent hydrogels by high-energy irradiation in the presence of crosslinking agent

    Science.gov (United States)

    Fekete, Tamás; Borsa, Judit; Takács, Erzsébet; Wojnárovits, László

    2016-01-01

    Superabsorbent hydrogels were prepared from aqueous solutions of four cellulose derivatives (carboxymethylcellulose Na-salt - CMC, methylcellulose - MC, hydroxyethylcellulose - HEC and hydroxypropylcellulose - HPC) by gamma irradiation initiated crosslinking. CMC was used for the majority of the measurements. N,N'-methylene-bis-acrylamide (MBA) crosslinking agent was used to modify the gel properties. The crosslink density increased with the MBA concentration, leading to an improved gel fraction and lower water uptake. The crosslinking efficiency was the highest up to 1 w/wpolymer% MBA concentration. Very high MBA content (10 w/wpolymer%) led to a heterogeneous gel structure. Gelation also occurred under milder conditions in the presence of MBA: good gel properties were achieved at significantly lower doses and solute concentrations as compared to crosslinker-free solutions. The time required to reach maximum water uptake increased with the degree of swelling in equilibrium. Swelling properties of CMC gels with lower water uptake showed lower sensitivity to the ionic strength of the solvent.

  16. Facile synthesis, characterization, and antimicrobial activity of cellulose-chitosan-hydroxyapatite composite material: a potential material for bone tissue engineering.

    Science.gov (United States)

    Mututuvari, Tamutsiwa M; Harkins, April L; Tran, Chieu D

    2013-11-01

    Hydroxyapatite (HAp) is often used as a bone-implant material because it is biocompatible and osteoconductive. However, HAp possesses poor rheological properties and it is inactive against disease-causing microbes. To improve these properties, we developed a green method to synthesize multifunctional composites containing: (1) cellulose (CEL) to impart mechanical strength; (2) chitosan (CS) to induce antibacterial activity thereby maintaining a microbe-free wound site; and (3) HAp. In this method, CS and CEL were co-dissolved in an ionic liquid (IL) and then regenerated from water. HAp was subsequently formed in situ by alternately soaking [CEL+CS] composites in aqueous solutions of CaCl2 and Na2 HPO4 . At least 88% of IL used was recovered for reuse by distilling the aqueous washings of [CEL+CS]. The composites were characterized using FTIR, XRD, and SEM. These composites retained the desirable properties of their constituents. For example, the tensile strength of the composites was enhanced 1.9 times by increasing CEL loading from 20% to 80%. Incorporating CS in the composites resulted in composites which inhibited the growth of both Gram positive (MRSA, S. aureus and VRE) and Gram negative (E. coli and P. aeruginosa) bacteria. These findings highlight the potential use of [CEL+CS+HAp] composites as scaffolds in bone tissue engineering.

  17. Synthesis of polyvinyl alcohol/cellulose nanofibril hybrid aerogel microspheres and their use as oil/solvent superabsorbents.

    Science.gov (United States)

    Zhai, Tianliang; Zheng, Qifeng; Cai, Zhiyong; Xia, Hesheng; Gong, Shaoqin

    2016-09-05

    Superhydrophobic and crosslinked poly(vinyl alcohol) (PVA)/cellulose nanofibril (CNF) aerogel microspheres were prepared via a combination of the water-in-oil (W/O) emulsification process with the freeze-drying process, followed by thermal chemical vapor deposition of methyltrichlorosilane. The oil phase and the cooling agent were judiciously selected to ensure that the frozen ice microspheres can be easily separated from the emulsion system. The silanized microspheres were highly porous with a bulk density ranging from 4.66 to 16.54mg/cm(3). The effects of the solution pH, stirring rate, and emulsifier concentration on the morphology and microstructure of the aerogel microspheres were studied. The highly porous structure of the ultralight aerogel microspheres demonstrated an ultrahigh crude oil absorption capacity (up to 116 times its own weight). This study provides a novel approach for the large-scale preparation of polymeric aerogel microspheres with well-controlled particle sizes that can be used for various applications including oil and chemical spill/leak clean-up.

  18. Synthesis of superhydrophobic ultralight aerogels from nanofibrillated cellulose isolated from natural reed for high-performance adsorbents

    Science.gov (United States)

    Jiao, Yue; Wan, Caichao; Qiang, Tiangang; Li, Jian

    2016-07-01

    Reed is one of the widely available aquatic plant resources, and its applications are generally limited to some traditional areas like papermaking and animals' fodder. Besides, most of reed is wasted or directly burned every year causing serious air pollution (like atmospheric haze). Therefore, it is worth to further develop new forms of high-value applications of reed. Herein, natural reed was collected to fabricate ultralight adsorbents namely nanofibrillated cellulose (NFC) aerogels via an easily operated method, which includes chemical purification, ultrasonication, and freeze drying. The NFC aerogels with an ultra-low density of 4.9 mg cm-3 were characterized by scanning electron microscopy, energy-dispersive X-ray spectrometer, Fourier transform infrared spectroscopy, X-ray diffraction, and thermogravimetric analysis. For acquiring good hydrophobicity, the NFC aerogels were subjected to a hydrophobic treatment by methyltrichlorosilane. The superhydrophobic NFC aerogels with contact angles of as high as 151°-155° have excellent adsorption efficiency (53-93 g g-1) for various organic solvents and waste oil. More importantly, the aerogels also exhibit favorable adsorption recyclability, which can maintain more than 80 % of the initial adsorption efficiency after the five cycles.

  19. Rational design, synthesis and preliminary antitumor activity evaluation of a chlorambucil derivative with potent DNA/HDAC dual-targeting inhibitory activity.

    Science.gov (United States)

    Xie, Rui; Li, Yan; Tang, Pingwah; Yuan, Qipeng

    2017-09-15

    Histone deacetylases (HDACs) play a pivotal role not only in gene expression but also in DNA repair. Herein, we report the successful design, synthesis and evaluation of a chlorambucil derivative named vorambucil with a hydroxamic acid tail as a DNA/HDAC dual-targeting inhibitor. Vorambucil obtained both potent DNA and HDACs inhibitory activities. Molecular docking results supported the initial pharmacophoric hypothesis and rationalized the potent inhibitory activity of vorambucil against HDAC1, HDAC2 and HDAC6. Vorambucil showed potent antiproliferative activity against all the test four cancer cell lines with IC50 values of as low as 3.2-6.2μM and exhibited 5.0-18.3-fold enhanced antiproliferative activity than chlorambucil. Vorambucil also significantly inhibits colony formation of A375 cancer cells. Further investigation showed that vorambucil remarkably induced apoptosis and arrested the cell cycle of A375 cells at G2/M phase. Vorambucil could be a promising candidate and a useful tool to elucidate the role of those DNA/HDAC dual-targeting inhibitors for cancer therapy. Copyright © 2017. Published by Elsevier Ltd.

  20. Synthesis of ∆3-2-Hydroxybakuchiol Analogues and Their Growth Inhibitory Activity against Rat UMR106 Cells

    Directory of Open Access Journals (Sweden)

    Qun Zhao

    2014-02-01

    Full Text Available A series of ∆3-2-hydroxybakuchiol analogues have been synthesized and tested for their growth inhibitory activity against rat UMR106 cells by using the MTT method. Some of them exhibit enhanced activities compared with the natural product, and the preliminary SAR profile shows that the chain tail on the natural product could be subtly modified to enhance the activity and the aromatic moiety or the terminal olefin on the main chain can also be modified without any evident loss of activity. The stereo-configuration of the quaternary chiral center has an important influence on the activity.

  1. Mitigation of Humic Acid Inhibition in Anaerobic Digestion of Cellulose by Addition of Various Salts

    NARCIS (Netherlands)

    Azman, S.; Khadem, A.F.; Zeeman, G.; Van Lier, J.B.; Plugge, C.M.

    2015-01-01

    Humic compounds are inhibitory to the anaerobic hydrolysis of cellulosic biomass. In this study, the impact of salt addition to mitigate the inhibitory effects of humic compounds was investigated. The experiment was conducted using batch tests to monitor the anaerobic hydrolysis of cellulose in the

  2. Synthesis and carbonic anhydrase inhibitory properties of amino acid - coumarin/quinolinone conjugates incorporating glycine, alanine and phenylalanine moieties.

    Science.gov (United States)

    Küçükbay, F Zehra; Küçükbay, Hasan; Tanc, Muhammet; Supuran, Claudiu T

    2016-12-01

    N-Protected amino acids (Gly, Ala and Phe) were reacted with amino substituted coumarin and quinolinone derivatives, leading to the corresponding N-protected amino acid-coumarin/quinolinone conjugates. The carbonic anhydrase (CA, EC 4.2.1.1) inhibitory activity of the new compounds was assessed against various human (h) isoforms, such as hCA I, hCA II, hCA IV and hCA XII. The quinolinone conjugates were inactive as enzyme inhibitors, whereas the coumarins were ineffective hCA I/II inhibitors (KIs > 50 μM) but were submicromolar hCA IV and XII inhibitors, with inhibition constants ranging between 92 nM and 1.19 μM for hCA IV, and between 0.11 and 0.79 μM for hCA XII. These coumarin derivatives, as many others reported earlier, thus show an interesting selective inhibitory profile for the membrane-bound over the cytosolic CA isoforms.

  3. Hyaluronidase Inhibitory Activity of Pentacylic Triterpenoids from Prismatomeris tetrandra (Roxb. K. Schum: Isolation, Synthesis and QSAR Study

    Directory of Open Access Journals (Sweden)

    Nor Hayati Abdullah

    2016-02-01

    Full Text Available The mammalian hyaluronidase degrades hyaluronic acid by the cleavage of the β-1,4-glycosidic bond furnishing a tetrasaccharide molecule as the main product which is a highly angiogenic and potent inducer of inflammatory cytokines. Ursolic acid 1, isolated from Prismatomeris tetrandra, was identified as having the potential to develop inhibitors of hyaluronidase. A series of ursolic acid analogues were either synthesized via structure modification of ursolic acid 1 or commercially obtained. The evaluation of the inhibitory activity of these compounds on the hyaluronidase enzyme was conducted. Several structural, topological and quantum chemical descriptors for these compounds were calculated using semi empirical quantum chemical methods. A quantitative structure activity relationship study (QSAR was performed to correlate these descriptors with the hyaluronidase inhibitory activity. The statistical characteristics provided by the best multi linear model (BML (R2 = 0.9717, R2cv = 0.9506 indicated satisfactory stability and predictive ability of the developed model. The in silico molecular docking study which was used to determine the binding interactions revealed that the ursolic acid analog 22 had a strong affinity towards human hyaluronidase.

  4. GIL, a new c-di-GMP binding protein domain involved in regulation of cellulose synthesis in enterobacteria

    OpenAIRE

    Fang, Xin; Ahmad, Irfan; Blanka, Andrea; Schottkowski, Marco; Cimdins, Annika; Galperin, Michael Y.; Römling, Ute; Gomelsky, Mark

    2014-01-01

    In contrast to numerous enzymes involved in c-di-GMP synthesis and degradation in enterobacteria, only a handful of c-di-GMP receptors/effectors have been identified. In search of new c-di-GMP receptors, we screened the Escherichia coli ASKA overexpression gene library using the Differential Radial Capillary Action of Ligand Assay (DRaCALA) with fluorescently and radioisotope-labeled c-di-GMP. We uncovered three new candidate c-di-GMP receptors in E. coli and characterized one of them, BcsE. ...

  5. 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

  6. Synthesis and classical pathway Complement inhibitory activity of C7-functionalized filifolinol derivatives, inspired in K-76 COOH.

    Science.gov (United States)

    Larghi, Enrique L; Operto, María A; Torres, Rene; Kaufman, Teodoro S

    2012-09-01

    A series of carboxylic acids carrying various functionalization on C-7 of their common 3H-spiro[benzofuran-2,1'-cyclohexane] skeleton were synthesized from filifolinol, as analogs of the natural Complement inhibitor K-76 COOH. In order to probe the relevance of the C-7 functionalization on their bioactivity, the ability of the analogs to inhibit Complement activation through the classical pathway was determined. The observed results suggest that functionalization of C-7 can modulate the inhibitory activity of the tested compounds. The 7-trifluoromethyl derivative was the compound with the lowest IC(50) value among the tested analogs (IC(50) = 100 μM), being more potent than K-76 COOH (IC(50) = 570 μM).

  7. 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.

  8. Synthesis of Cellulose-g-PMMA and Its Micelles Using as Drug Carriers%cellulose-g-PMMA的合成及其胶束作为药物载体的研究

    Institute of Scientific and Technical Information of China (English)

    钟黎黎; 高源; 张力平

    2015-01-01

    以纤维素为原料,离子液体为反应介质,首先制备了纤维素氯乙酸酯大分子引发剂,然后以甲基丙烯酸甲酯(M MA)为单体,纤维素氯乙酸酯/CuBr/2,2-联吡啶为引发体系,进行了原子转移自由基聚合反应,合成了纤维素接枝甲基丙烯酸甲酯聚合物(cellulose-g-PMMA).利用傅里叶变换红外光谱、X射线衍射、热重分析等对cellulose-g-PMMA的结构与性能进行了表征.纤维素的结晶度57.90%,cellulose-g-PMMA的结晶度降至38.39%.利用原子力显微镜观察到cellulose-g-PMMA在溶剂丙酮中的平均粒径在40 ~70nm左右.利用透射电镜观察到该聚合物胶束呈圆球状分布,粒径在200 nm左右,具有内核-外壳结构.以阿司匹林作为模型药物负载于聚合物胶束内,探讨了纤维素改性程度对药物释放率的影响.在37℃时,接枝反应3h得到的cellulose-g-PMMA作为药物载体释放药物72 h后,释药率可达88.9%,具有较好释药效果.

  9. One-Pot Synthesis of Biocompatible Silver Nanoparticle Composites from Cellulose and Keratin: Characterization and Antimicrobial Activity.

    Science.gov (United States)

    Tran, Chieu D; Prosenc, Franja; Franko, Mladen; Benzi, Gerald

    2016-12-21

    A novel, simple method was developed to synthesize biocompatible composites containing 50% cellulose (CEL) and 50% keratin (KER) and silver in the form of either ionic (Ag(+)) or Ag(0) nanoparticles (Ag(+)NPs or Ag(0)NPs). In this method, butylmethylimmidazolium chloride ([BMIm(+)Cl(-)]), a simple ionic liquid, was used as the sole solvent and silver chloride was added to the [BMIm(+)Cl(-)] solution of [CEL+KER] during the dissolution process. The silver in the composites can be maintained as ionic silver (Ag(+)) or completely converted to metallic silver (Ag(0)) by reducing it with NaBH4. The results of spectroscopy [Fourier transform infrared and X-ray diffraction (XRD)] and imaging [scanning electron microscopy (SEM)] measurements confirm that CEL and KER remain chemically intact and homogeneously distributed in the composites. Powder XRD and SEM results show that the silver in the [CEL+KER+Ag(+)] and [CEL+KER+Ag(0)] composites is homogeneously distributed throughout the composites in either Ag(+) (in the form of AgClNPs) or Ag(0)NPs form with sizes of 27 ± 2 or 9 ± 1 nm, respectively. Both composites were found to exhibit excellent antibacterial activity against many bacteria including Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, methicillin-resistant S. aureus (MRSA), and vancomycin-resistant Enterococus faecalis (VRE). The antibacterial activity of both composites increases with the Ag(+) or Ag(0) content in the composites. More importantly, for the same bacteria and the same silver content, the [CEL+KER+AgClNPs] composite is relatively more toxic than [CEL+KER+Ag(0)NPs] composite. Experimental results confirm that there was hardly any Ag(0)NPs release from the [CEL+KER+Ag(0)NPs] composite, and hence its antimicrobial activity and biocompatibility is due not to any released Ag(0)NPs but rather entirely to the Ag(0)NPs embedded in the composite. Both AgClNPs and Ag(0)NPs were found to be toxic to human fibroblasts at higher concentration

  10. Studies on cellulose degradation by a Thermoactinimyces Sp

    Energy Technology Data Exchange (ETDEWEB)

    1977-04-01

    Progress in studies on the mechanism of cellulose degradation by Thermoactinomyces is reported. Two pure cellulosic substrates AVICEL and SOLKA FLOC were used in the experiments. A low substituted carboxymethylcellulose (Hercules 4M CMC), cellobiose, and glucose were also used as growth substrates. Results indicate that glucose is not inhibitory to growth up to 1% concetrations, and that cellobiose may not be a good inducer of the cellobiase enzyme activity. Production of biomass and soluble protein was found to be 50% greater on crystalline AVICEL than on the amorphous SOLKA FLOC, even though approximately the same amount and rate of cellulose degradation occurred. A model for cellulose digestion is presented. (JGB)

  11. Expression of a mutant form of cellulose synthase AtCesA7 causes dominant negative effect on cellulose biosynthesis.

    Science.gov (United States)

    Zhong, Ruiqin; Morrison, W Herbert; Freshour, Glenn D; Hahn, Michael G; Ye, Zheng-Hua

    2003-06-01

    Cellulose synthase catalytic subunits (CesAs) have been implicated in catalyzing the biosynthesis of cellulose, the major component of plant cell walls. Interactions between CesA subunits are thought to be required for normal cellulose synthesis, which suggests that incorporation of defective CesA subunits into cellulose synthase complex could potentially cause a dominant effect on cellulose synthesis. However, all CesA mutants so far reported have been shown to be recessive in terms of cellulose synthesis. In the course of studying the molecular mechanisms regulating secondary wall formation in fibers, we have found that a mutant allele of AtCesA7 gene in the fra5 (fragile fiber 5) mutant causes a semidominant phenotype in the reduction of fiber cell wall thickness and cellulose content. The fra5 missense mutation occurred in a conserved amino acid located in the second cytoplasmic domain of AtCesA7. Overexpression of the fra5 mutant cDNA in wild-type plants not only reduced secondary wall thickness and cellulose content but also decreased primary wall thickness and cell elongation. In contrast, overexpression of the fra6 mutant form of AtCesA8 did not cause any reduction in cell wall thickness and cellulose content. These results suggest that the fra5 mutant protein may interfere with the function of endogenous wild-type CesA proteins, thus resulting in a dominant negative effect on cellulose biosynthesis.

  12. Inhibitory noise

    Directory of Open Access Journals (Sweden)

    Alain Destexhe

    2010-03-01

    Full Text Available Cortical neurons in vivo may operate in high-conductance states, in which the major part of the neuron's input conductance is due to synaptic activity, sometimes several-fold larger than the resting conductance. We examine here the contribution of inhibition in such high-conductance states. At the level of the absolute conductance values, several studies have shown that cortical neurons in vivo are characterized by strong inhibitory conductances. However, conductances are balanced and spiking activity is mostly determined by fluctuations, but not much is known about excitatory and inhibitory contributions to these fluctuations. Models and dynamic-clamp experiments show that, during high-conductance states, spikes are mainly determined by fluctuations of inhibition, or by inhibitory noise. This stands in contrast to low-conductance states, in which excitatory conductances determine spiking activity. To determine these contributions from experimental data, maximum likelihood methods can be designed and applied to intracellular recordings in vivo. Such methods indicate that action potentials are indeed mostly correlated with inhibitory fluctuations in awake animals. These results argue for a determinant role for inhibitory fluctuations in evoking spikes, and do not support feed-forward modes of processing, for which opposite patterns are predicted.

  13. GCN2 has inhibitory effect on human immunodeficiency virus-1 protein synthesis and is cleaved upon viral infection.

    Directory of Open Access Journals (Sweden)

    Javier del Pino

    Full Text Available The reversible phosphorylation of the alpha-subunit of eukaryotic translation initiation factor 2 (eIF2alpha is a well-characterized mechanism of translational control in response to a wide variety of cellular stresses, including viral infection. Beside PKR, the eIF2alpha kinase GCN2 participates in the cellular response against viral infection by RNA viruses with central nervous system tropism. PKR has also been involved in the antiviral response against HIV-1, although this antiviral effect is very limited due to the distinct mechanisms evolved by the virus to counteract PKR action. Here we report that infection of human cells with HIV-1 conveys the proteolytic cleavage of GCN2 and that purified HIV-1 and HIV-2 proteases produce direct proteolysis of GCN2 in vitro, abrogating the activation of GCN2 by HIV-1 RNA. Transfection of distinct cell lines with a plasmid encoding an HIV-1 cDNA clone competent for a single round of replication resulted in the activation of GCN2 and the subsequent eIF2alpha phosphorylation. Moreover, transfection of GCN2 knockout cells or cells with low levels of phosphorylated eIF2alpha with the same HIV-1 cDNA clone resulted in a marked increase of HIV-1 protein synthesis. Also, the over-expression of GCN2 in cells led to a diminished viral protein synthesis. These findings suggest that viral RNA produced during HIV-1 infection activates GCN2 leading to inhibition of viral RNA translation, and that HIV-1 protease cleaves GCN2 to overcome its antiviral effect.

  14. Synthesis of Highly Polymerized Water-soluble Cellulose Acetate by the Side Reaction in Carboxylate Ionic Liquid 1-ethyl-3-methylimidazolium Acetate

    Science.gov (United States)

    Pang, Jinhui; Liu, Xin; Yang, Jun; Lu, Fachuang; Wang, Bo; Xu, Feng; Ma, Mingguo; Zhang, Xueming

    2016-09-01

    In the present study, we describe a novel one-step method to prepare water-soluble cellulose acetate (WSCA) with higher degree of polymerization values (DP = 650–680) by in situ activation of carboxyl group in ionic liquid. First of all, cellulose was dissolved in 1-ethyl-3-methylimidazolium acetate (EmimAc) and reacted with dichloroacetyl chloride (Cl2AcCl) in order to make cellulose dichloroacetate. Under various conditions, a series of water soluble products were produced. Elemental analysis and NMR results confirmed that they were cellulose acetate with DS (degree of substitution) values in the range from 0.30 to 0.63. NMR studies demonstrated that Cl2AcCl reacted with acetate anion of EmimAc producing a mixed anhydride that acetylated cellulose. Other acylating reagents such as benzoyl chloride, chloroacetyl chloride can also work similarly. 2D NMR characterization suggested that 6-mono-O-acetyl moiety, 3,6-di-O-acetylcellulose and 2,6-di-O-acetyl cellulose were all synthesized and the reactivity of hydroxyl groups in anhydro-glucose units was in the order C-6>C-3>C-2. This work provides an alternative way to make WSCA, meanwhile, also services as a reminder that the activity of EmimAc toward carbohydrate as acylating reagents could be a problem, because the expected acylated products may not be resulted and recycling of this ionic liquid could also be difficult.

  15. Synthesis of Highly Polymerized Water-soluble Cellulose Acetate by the Side Reaction in Carboxylate Ionic Liquid 1-ethyl-3-methylimidazolium Acetate

    Science.gov (United States)

    Pang, Jinhui; Liu, Xin; Yang, Jun; Lu, Fachuang; Wang, Bo; Xu, Feng; Ma, Mingguo; Zhang, Xueming

    2016-01-01

    In the present study, we describe a novel one-step method to prepare water-soluble cellulose acetate (WSCA) with higher degree of polymerization values (DP = 650–680) by in situ activation of carboxyl group in ionic liquid. First of all, cellulose was dissolved in 1-ethyl-3-methylimidazolium acetate (EmimAc) and reacted with dichloroacetyl chloride (Cl2AcCl) in order to make cellulose dichloroacetate. Under various conditions, a series of water soluble products were produced. Elemental analysis and NMR results confirmed that they were cellulose acetate with DS (degree of substitution) values in the range from 0.30 to 0.63. NMR studies demonstrated that Cl2AcCl reacted with acetate anion of EmimAc producing a mixed anhydride that acetylated cellulose. Other acylating reagents such as benzoyl chloride, chloroacetyl chloride can also work similarly. 2D NMR characterization suggested that 6-mono-O-acetyl moiety, 3,6-di-O-acetylcellulose and 2,6-di-O-acetyl cellulose were all synthesized and the reactivity of hydroxyl groups in anhydro-glucose units was in the order C-6>C-3>C-2. This work provides an alternative way to make WSCA, meanwhile, also services as a reminder that the activity of EmimAc toward carbohydrate as acylating reagents could be a problem, because the expected acylated products may not be resulted and recycling of this ionic liquid could also be difficult. PMID:27644545

  16. Enzymic synthesis of alpha- and beta-D-glucosides of 1-deoxynojirimycin and their glycosidase inhibitory activities.

    Science.gov (United States)

    Asano, N; Oseki, K; Kaneko, E; Matsui, K

    1994-05-20

    1-Deoxynojirimycin (1) is a potent inhibitor of mammalian and rice alpha-glucosidase. Several glucosides of 1 were synthesized by use of the native and immobilized enzyme and their effect on various enzymes was investigated. Transglucosylation reactions using rice alpha-glucosidase, yeast alpha- and beta-glucosidases purified from Rhodotorula lactosa were performed with maltose or cellobiose as a glucose donor and N-(benzyloxycarbonyl)-1-deoxynojirimycin (2) as an acceptor. The transglucosylation reaction using native rice alpha-glucosidase afforded 3-O-alpha-D-glucopyranosyl-N-(benzyloxycarbonyl)-1-deoxynojirimycin (4), 4-O-alpha-D-glucopyranosyl-N-(benzyloxycarbonyl)-1-deoxynojirimycin (5), and 2-O-alpha-D-glucopyranosyl-N-(benzyloxycarbonyl)-1-deoxynojirimycin (3) in yields of 40, 13, and 2%, respectively, after 30 min. The transglucosylation reaction using immobilized rice alpha-glucosidase was similar to that using the native enzyme. In the system using native yeast alpha-glucosidase, 3, 5, and 4 were formed in yields of 34, 13, and 6%, respectively, after 15 h. The immobilization of yeast alpha-glucosidase caused a significant decrease in transglucosylation activity. Yeast beta-glucosidase showed a high transglucosylation activity and incubation with the reaction system afforded 2-O-beta-D-glucopyranosyl-N-(benzyloxycarbonyl)-1-deoxynojirimycin (6) and 4-O-beta-D-glucopyranosyl-N-(benzyloxycarbonyl)-1-deoxynojirimycin (7) in yields of 69 and 3%, respectively, after 3 h. The transglucosylation reaction using immobilized yeast beta-glucosidase preferentially afforded 6 in a yield of 73% after 3 h. After removal of N-benzyloxycarbonyl group from the product glucosides, their glycosidase inhibitory activities were measured. 3-O-alpha-D-Glucopyranosyl-1-deoxynojirimycin (9) retained the potent inhibition of 1 against rat intestinal sucrase activity and was more effective than 1 against rice alpha-glucosidase. 4-O-alpha-D-Glucopyranosyl-1-deoxynojirimycin (10

  17. Synthesis, in vitro β-glucuronidase inhibitory activity and in silico studies of novel (E)-4-Aryl-2-(2-(pyren-1-ylmethylene)hydrazinyl)thiazoles.

    Science.gov (United States)

    Salar, Uzma; Khan, Khalid Mohammed; Syed, Shazia; Taha, Muhammad; Ali, Farman; Ismail, Nor Hadiani; Perveen, Shahnaz; Wadood, Abdul; Ghufran, Mehreen

    2017-02-01

    Current research is based on the synthesis of novel (E)-4-aryl-2-(2-(pyren-1-ylmethylene)hydrazinyl)thiazole derivatives (3-15) by adopting two steps route. First step was the condensation between the pyrene-1-carbaldehyde (1) with the thiosemicarbazide to afford pyrene-1-thiosemicarbazone intermediate (2). While in second step, cyclization between the intermediate (2) and phenacyl bromide derivatives or 2-bromo ethyl acetate was carried out. Synthetic derivatives were structurally characterized by spectroscopic techniques such as EI-MS, (1)H NMR and (13)C NMR. Stereochemistry of the iminic double bond was confirmed by NOESY analysis. All pure compounds 2-15 were subjected for in vitro β-glucuronidase inhibitory activity. All molecules were exhibited excellent inhibition in the range of IC50=3.10±0.10-40.10±0.90μM and found to be even more potent than the standard d-saccharic acid 1,4-lactone (IC50=48.38±1.05μM). Molecular docking studies were carried out to verify the structure-activity relationship. A good correlation was perceived between the docking study and biological evaluation of active compounds.

  18. Mechanochemical synthesis and in vitro anti-Helicobacter pylori and uresase inhibitory activities of novel zinc(II)-famotidine complex.

    Science.gov (United States)

    Amin, Muhammad; Iqbal, Mohammad S; Hughes, Roy W; Khan, Safyan A; Reynolds, Paul A; Enne, Virve I; Sajjad-ur-Rahman; Mirza, Akmal S

    2010-06-01

    The mechanochemical synthesis and characterization of a zinc complex with famotidine is described. The complex was characterized by microanalysis and a number of spectroscopic techniques. The complex was of M:L dihydrate type. Derivatization of famotidine with zinc appears to enhance the activity of the drug by inhibiting the growth of Helicobacter pylori (two reference and 34 clinical isolates). The complex inhibited the growth of H. pylori in an MIC range of 1-8 microg mL(-1). The anti-H. pylori activity of the zinc-famotidine complex against antibiotic-resistant strains was nearly comparable to that of antibiotic-susceptible strains. The complex was found to be far less toxic than the parent drug, as demonstrated by its higher LD(50) value. In the human urease enzyme inhibition assay the complex exhibited significant inhibition. The new complex appears to be more useful in eradicating both the antibiotic-susceptible and antibiotic-resistant strains of H. pylori.

  19. Flash pyrolysis at high temperature of ligno-cellulosic biomass and its components - production of synthesis gas; Pyrolyse flash a haute temperature de la biomasse ligno-cellulosique et de ses composes - production de gaz de synthese

    Energy Technology Data Exchange (ETDEWEB)

    Couhert, C

    2007-11-15

    Pyrolysis is the first stage of any thermal treatment of biomass and governs the formation of synthesis gas for the production of electricity, hydrogen or liquid fuels. The objective of this work is to establish a link between the composition of a biomass and its pyrolysis gas. We study experimental flash pyrolysis and fix the conditions in which quantities of gas are maximal, while aiming at a regime without heat and mass transfer limitations (particles about 100 {mu}m): temperature of 950 C and residence time of about 2 s. Then we try to predict gas yields of any biomass according to its composition, applicable in this situation where thermodynamic equilibrium is not reached. We show that an additivity law does not allow correlating gas yields of a biomass with fractions of cellulose, hemi-cellulose and lignin contained in this biomass. Several explanations are suggested and examined: difference of pyrolytic behaviour of the same compound according to the biomass from which it is extracted, interactions between compounds and influence of mineral matter. With the aim of industrial application, we study pyrolysis of millimetric and centimetric size particles, and make a numerical simulation of the reactions of pyrolysis gases reforming. This simulation shows that the choice of biomass affects the quantities of synthesis gas obtained. (author)

  20. 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.

  1. Synthesis and properties of cellulose functionalized -4, 4'-(propane-2, 2'-diyl) diphenol-SiO2/TiO2 hybrid nanocomposites materials for high performance applications

    Science.gov (United States)

    Ramesh, Sivalingam; Kim, Gwang-Hoon; Kim, Heung-Soo; Kim, Jaehwan; Kim, Joo-Hyung

    2013-04-01

    The general class of organic-inorganic hybrid nanocomposites materials is a fast growing area of research. The significant effort is focused on the ability to control the nanoscale structures via organic functional synthetic approaches with inorganic metal oxides. The properties of nanocomposites material depends on the properties of their individual components but also their morphological and interfacial characteristics. This rapidly expanding field is generating many exciting new materials with novel properties. Mainly, cellulose is considered as the richest renewable materials are presently among the most promising candidates for use in photonics due to their versatility, flexibility, light weight, low cost and ease of modification. Cellulose-metal oxide nanomaterials were developed the technologies to manipulate selfassembly and multifunctionallity, of new technologies to the point where industry can produce advanced and costcompetitive cellulose metal oxide hybrid materials. Therefore, the present study is focused on cellulose-functionalized - 4, 4'-(propane-2, 2'-diyl) diphenol-SiO2/TiO2 hybrid nano-composites materials by in-situ sol-gel process. The chemical and morphological properties of cellulose-functionalized SiO2/TiO2 materials via covalent crosslinking hybrids were characterized by FTIR, XRD, TGA, DSC, SEM, TEM and optical properties.

  2. Efficient cellulose solvent: quaternary ammonium chlorides.

    Science.gov (United States)

    Kostag, Marc; Liebert, Tim; El Seoud, Omar A; Heinze, Thomas

    2013-10-01

    Pure quaternary tetraalkylammonium chlorides with one long alkyl chain dissolved in various organic solvents constitute a new class of cellulose solvents. The electrolytes are prepared in high yields and purity by Menshutkin quaternization, an inexpensive and easy synthesis route. The pure molten tetraalkylammonium chlorides dissolve up to 15 wt% of cellulose. Cosolvents, including N,N-dimethylacetamide (DMA), may be added in large excess, leading to a system of decreased viscosity. Contrary to the well-established solvent DMA/LiCl, cellulose dissolves in DMA/quaternary ammonium chlorides without any pretreatment. Thus, the use of the new solvent avoids some disadvantages of DMA/LiCl and ionic liquids, the most extensively employed solvents for homogeneous cellulose chemistry.

  3. 咪唑阳离子纤维素的合成及性能研究%Synthesis and properties of alkylimidazolium cationic cellulose

    Institute of Scientific and Technical Information of China (English)

    陈春明; 赖月云

    2011-01-01

    以纸浆纤维素为原料,以功能化离子液体氯化1-(3-氯-2-羟丙基)3-甲基咪唑为阳离子化剂和溶剂,合成了咪唑阳离子纤维素;探讨了反应条件对咪唑阳离子纤维素的取代度的影响,并对其结构与性能进行了表征.结果表明:纸浆纤维素中NaOH质量分数为20%,反应温度为80℃,反应时间为3h时,咪唑阳离子纤维素的取代度达0.85;红外光谱分析证实纤维素实现了阳离子化;当咪唑阳离子纤维素质量浓度为15 mg/L时,高岭土悬浊液的浊度去除率达92.5%.%Alkylimidazolium cationic cellulose was synthesized using pulp cellulose as raw material and the functional ionic liquid of 1-3-chloro-2-hydroxypropyltrimethylammoniurn chloride as cationizing agent and solvent. The effects of reaction conditions on the degree of substitution (DS) of alkylimidazolium cationic cellulose were discussed. The structure and properties of alkylimidazolium cationic cellulose were characterized. The result showed that alkylimidazolium catioinc cellulose had the degree of substitution of 0. 85 when the mass fraction of NaOH was 20% in cellulose and the reaction temperature and time were 80℃ and 3 h, respectively. The infrared spectrography results showed that the cationization of cellulose was successfully implemented. The turbidity removal rate of kaolin suspension was 92.5% when the concentration of alkylimidazolium cationic cellulose was 15 mg/L.

  4. 2-(2-(4-Benzoylpiperazin-1-ylethylisoindoline-1,3-dione derivatives: Synthesis, docking and acetylcholinesterase inhibitory evaluation as anti-alzheimer agents

    Directory of Open Access Journals (Sweden)

    Ahmad Mohammadi-Farani

    2017-01-01

    Full Text Available Objective(s: Alzheimer’s disease (AD as progressive cognitive decline and the most common form of dementia is due to degeneration of the cholinergic neurons in the brain. Therefore, administration of the acetylcholinesterase (AChE inhibitors such as donepezil is the first choice for treatment of the AD. In the present study, we focused on the synthesis and anti-cholinesterase evaluation of new donepezil like analogs. Materials and Methods: A new series of phthalimide derivatives (compounds 4a-4j were synthesized via Gabriel protocol and subsequently amidation reaction was performed using various benzoic acid derivatives. Then, the corresponding anti-acetylcholinesterase activity of the prepared derivatives (4a-4j was assessed by utilization of the Ellman's test and obtained results were compared to donepezil. Besides, docking study was also carried out to explore the likely in silico binding interactions.  Results: According to the obtained results, electron withdrawing groups (Cl, F at position 3 and an electron donating group (methoxy at position 4 of the phenyl ring enhanced the acetylcholinesterase inhibitory activity. Compound 4e (m-Fluoro, IC50 = 7.1 nM and 4i (p-Methoxy, IC50 = 20.3 nM were the most active compounds in this series and exerted superior potency than donepezil (410 nM. Moreover, a similar binding mode was observed in silico for all ligands in superimposition state with donepezil into the active site of acetylcholinesterase. Conclusion: Studied compounds could be potential leads for discovery of novel anti-Alzheimer agents in the future.

  5. BIOSYNTHESIS OF BACTERIAL CELLULOSE BY МEDUSOMYCES GISEVII

    Directory of Open Access Journals (Sweden)

    E. K. Gladysheva

    2015-01-01

    Full Text Available Summary: Bacterial cellulose is an organic material that is synthesized by microorganisms extracellularly. Bacterial cellulose can be used in various industries. Especially, bacterial cellulose has found its application basically in medicine. The production of bacterial cellulose is a complicated and long process. The principal criterion for the process to be successful is bacterial cellulose to be obtained in a higher yield. Russia is lacking an operating facility to produce bacterial cellulose; therefore, research in this art is the hottest topic. This paper reports details on the biosynthesis of bacterial cellulose by the Мedusomyces gisevii microbe and investigates the effect of active acidity level on the bacterial cellulose synthesis. It was found that the synthesis of bacterial cellulose by the symbiosis of Мedusomyces gisevii does not require pH to be artificially maintained. The substrate concentration effect on the bacterial cellulose yield was also examined. The bacterial cellulose synthesis was witnessed to be conjugated with the acetic-acid bacterium growth, and conditions corresponding to a maximal bacterial cells number correspond to a maximum microbial cellulose yield. The maximal bacterial cell number was observed when the glucose concentration in the broth was 20 g/l; as the glucose concentration was increased to 55 g/L, the acetic-acid bacterial cell number diminished in inverse proportion to the substrate concentration, which is likely due to the substrate inhibition. A glucose concentration of 15 g/l and lower is not enough, causing a decrease in the cell number, which is directly proportional to a decline in the substrate concentration. The maximum bacterial cellulose yield (8.7-9.0 % was achieved at an initial glucose concentration of 20-25 g/l in the broth. The conditions providing the maximum bacterial cellulose yield gave an enlarged bacterial cellulose specimen 605 g in weight. The physicochemical properties of the

  6. Chemical genetics to examine cellulose biosynthesis

    Directory of Open Access Journals (Sweden)

    Seth eDebolt

    2013-01-01

    Full Text Available Long-term efforts to decode plant cellulose biosynthesis via molecular genetics and biochemical strategies are being enhanced by the ever-expanding scale of omics technologies. An alternative approach to consider are the prospects for inducing change in plant metabolism using exogenously supplied chemical ligands. Cellulose biosynthesis inhibitors (CBI have been identified among known herbicides, during diverse combinatorial chemical libraries screens, and natural chemical screens from microbial agents. In this review, we summarize the current knowledge of the inhibitory effects of CBIs and further group them by how they influence fluorescently tagged cellulose synthase A (CESA proteins. Additional attention is paid to the continuing development of the CBI toolbox to explore the cell biology and genetic mechanisms underpinning effector molecule activity.

  7. 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.

  8. Synthesis of Cellulose-2,3-bis(3,5-dimethylphenylcarbamate) in an Ionic Liquid and Its Chiral Separation Efficiency as Stationary Phase

    Science.gov (United States)

    Liu, Runqiang; Zhang, Yijun; Bai, Lianyang; Huang, Mingxian; Chen, Jun; Zhang, Yuping

    2014-01-01

    A chiral selector of cellulose-2,3-bis(3,5-dimethylphenylcarbamate) (CBDMPC) was synthesized by reacting 3,5-dimethylphenyl isocyanate with microcrystalline cellulose dissolved in an ionic liquid of 1-allyl-3-methyl-imidazolium chloride (AMIMCl). The obtained chiral selector was effectively characterized by infrared spectroscopy, elemental analysis and 1H NMR. The selector was reacted with 3-aminopropylsilanized silica gel and the CBDMPC bonded chiral stationary phase (CSP) was obtained. Chromatographic evaluation of the prepared CSPs was conducted by high performance liquid chromatographic (HPLC) and baseline separation of three typical fungicides including hexaconazole, metalaxyl and myclobutanil was achieved using n-hexane/isopropanol as the mobile phase with a flow rate 1.0 mL/min. Experimental results also showed that AMIMCl could be recycled easily and reused in the preparation of CSPs as an effective reaction media. PMID:24733066

  9. Synthesis of Cellulose-2,3-bis(3,5-dimethylphenylcarbamate in an Ionic Liquid and Its Chiral Separation Efficiency as Stationary Phase

    Directory of Open Access Journals (Sweden)

    Runqiang Liu

    2014-04-01

    Full Text Available A chiral selector of cellulose-2,3-bis(3,5-dimethylphenylcarbamate (CBDMPC was synthesized by reacting 3,5-dimethylphenyl isocyanate with microcrystalline cellulose dissolved in an ionic liquid of 1-allyl-3-methyl-imidazolium chloride (AMIMCl. The obtained chiral selector was effectively characterized by infrared spectroscopy, elemental analysis and 1H NMR. The selector was reacted with 3-aminopropylsilanized silica gel and the CBDMPC bonded chiral stationary phase (CSP was obtained. Chromatographic evaluation of the prepared CSPs was conducted by high performance liquid chromatographic (HPLC and baseline separation of three typical fungicides including hexaconazole, metalaxyl and myclobutanil was achieved using n-hexane/isopropanol as the mobile phase with a flow rate 1.0 mL/min. Experimental results also showed that AMIMCl could be recycled easily and reused in the preparation of CSPs as an effective reaction media.

  10. SYNTHESIS AND CHARACTERISTICS OF GRAFT COPOLYMERS OF POLY (BUTYL ACRYLATE AND CELLULOSE WITH ULTRASONIC PROCESSING AS A MATERIAL FOR OIL ABSORPTION

    Directory of Open Access Journals (Sweden)

    Ping Qu

    2011-11-01

    Full Text Available A series of materials used for oil absorption based on cellulose fiber grafted with butyl acrylate (BuAc have been prepared by radical polymerization under ultrasonic waves processing. Effects of ultrasonic dose for the maximum graft yield were considered. The dependency of optimum conditions for oil absorption rate on parameters such as ultrasonic processing time and ultrasonic power were also determined. Fourier infrared (FT-IR analysis was used to confirm the chemical reaction taking place between cellulose and butyl acrylate. The thermogravimetric behavior of the graft copolymer was characterized by thermogravimetric analysis (TGA. Scanning electron microscope (SEM analysis was used to determine the surface structure of the grafted material. With the increase of the ultrasonic treatment dose, the surface of the ultrasonic processed material became more regular, and the material was transformed into a homogeneous network polymer having a good structure and good adsorbing ability.

  11. A green method for the synthesis of bis-indolylmethanes and 3,3 -indolyloxindole derivatives using cellulose sulfuric acid under solvent-free conditions

    Institute of Scientific and Technical Information of China (English)

    Heshmatollah; Alinezhad; Asefeh; Hagh; Haghighi; Fatemeh; Salehian

    2010-01-01

    A highly efficient green protocol for the preparation of bis-indolylmethanes,bis-2-methylindolylmethanes,bis-1-methylindolylmethanes and 3,3'-diindolyloxindole derivatives from the reaction of indoles with various aldehydes and ketones in the presence of cellulose sulfuric acid under solvent-free conditions is reported.The significant features of this procedure are high yields of the products,mild reaction,solvent-free condition and non-toxicity of the catalyst.

  12. 羟丙甲基纤维素的合成工艺的改进研究%Research on Improvement of Hydroxypropyl Methyl Cellulose Synthesis Process

    Institute of Scientific and Technical Information of China (English)

    费玉元

    2015-01-01

    Based on existing synthetic methods of hydroxypropyl methyl cellulose, by using nitrogen protection alkalization and step-by-step etherification method, high viscosity of hydroxypropyl methyl cellulose was prepared. The hydroxypropyl methyl cellulose (HPMC) produced with this method has good dispersion performance in cold water, high viscosity, thickening water performance, and is suitable for the production of construction glue, can be also used in laying bricks or stones wall, plaster, paint, sealing construction, and is also suitable for dry mortar.%基于现有羟丙基甲基纤维素合成方法的研究,采用氮气保护碱化和分步醚化方法,制得具有较高黏度的羟丙基甲基纤维素。该方法合成的羟丙基甲基纤维素(HPMC)具有在冷水中分散性能好、黏度高、增稠保水性能好的优点,适合建筑用的胶水的生产,可用于砌墙、抹灰、粉刷、嵌缝等施工中,同时也适合用于干混凝砂浆。

  13. Genome sequence and plasmid transformation of the model high-yield bacterial cellulose producer Gluconacetobacter hansenii ATCC 53582

    Science.gov (United States)

    Florea, Michael; Reeve, Benjamin; Abbott, James; Freemont, Paul S.; Ellis, Tom

    2016-03-01

    Bacterial cellulose is a strong, highly pure form of cellulose that is used in a range of applications in industry, consumer goods and medicine. Gluconacetobacter hansenii ATCC 53582 is one of the highest reported bacterial cellulose producing strains and has been used as a model organism in numerous studies of bacterial cellulose production and studies aiming to increased cellulose productivity. Here we present a high-quality draft genome sequence for G. hansenii ATCC 53582 and find that in addition to the previously described cellulose synthase operon, ATCC 53582 contains two additional cellulose synthase operons and several previously undescribed genes associated with cellulose production. In parallel, we also develop optimized protocols and identify plasmid backbones suitable for transformation of ATCC 53582, albeit with low efficiencies. Together, these results provide important information for further studies into cellulose synthesis and for future studies aiming to genetically engineer G. hansenii ATCC 53582 for increased cellulose productivity.

  14. 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.

  15. Three-component synthesis of pyrano[2,3-d]-pyrimidine dione derivatives facilitated by sulfonic acid nanoporous silica (SBA-Pr-SO3H and their docking and urease inhibitory activity

    Directory of Open Access Journals (Sweden)

    Ghodsi Mohammadi Ziarani

    2013-01-01

    Full Text Available A straightforward and efficient method for the synthesis of pyrano[2,3-d]pyrimidine diones derivatives from the reaction of barbituric acid, malononitrile and various aromatic aldehydes using SBA-Pr-SO3H as a nanocatalyst is reported.ResultsReactions proceed with high efficiency under solvent free conditions. Urease inhibitory activity of pyrano[2,3-d]pyrimidine diones derivatives were tested against Jack bean urease using phenol red method. Three compounds of 4a, 4d and 4l were not active in urease inhibition test, but compound 4a displayed slight urease activation properties. Compounds 4b, 4k, 4f, 4e, 4j, 4g and 4c with hydrophobic substitutes on phenyl ring, showed good inhibitory activity (19.45-279.14 muM.DiscussionThe compounds with electron donating group and higher hydrophobic interaction with active site of enzyme prevents hydrolysis of substrate. Electron withdrawing groups such as nitro at different position and meta-methoxy reduced urease inhibitory activity. Substitution of both hydrogen of barbituric acid with methyl group will convert inhibitor to activator.

  16. Three-component synthesis of pyrano[2,3-d]-pyrimidine dione derivatives facilitated by sulfonic acid nanoporous silica (SBA-Pr-SO3H and their docking and urease inhibitory activity

    Directory of Open Access Journals (Sweden)

    Ziarani Ghodsi Mohammadi

    2013-01-01

    Full Text Available Abstract Background A straightforward and efficient method for the synthesis of pyrano[2,3-d]pyrimidine diones derivatives from the reaction of barbituric acid, malononitrile and various aromatic aldehydes using SBA-Pr-SO3H as a nanocatalyst is reported. Results Reactions proceed with high efficiency under solvent free conditions. Urease inhibitory activity of pyrano[2,3-d]pyrimidine diones derivatives were tested against Jack bean urease using phenol red method. Three compounds of 4a, 4d and 4l were not active in urease inhibition test, but compound 4a displayed slight urease activation properties. Compounds 4b, 4k, 4f, 4e, 4j, 4g and 4c with hydrophobic substitutes on phenyl ring, showed good inhibitory activity (19.45-279.14 μM. Discussion The compounds with electron donating group and higher hydrophobic interaction with active site of enzyme prevents hydrolysis of substrate. Electron withdrawing groups such as nitro at different position and meta-methoxy reduced urease inhibitory activity. Substitution of both hydrogen of barbituric acid with methyl group will convert inhibitor to activator.

  17. Enhancing the versatility of alternate current biosusceptometry (ACB) through the synthesis of a dextrose-modified tracer and a magnetic muco-adhesive cellulose gel

    Energy Technology Data Exchange (ETDEWEB)

    Martins, Murillo L., E-mail: murillolongo@gmail.com [Niels Bohr Institute, University of Copenhagen, DK-2100 Copenhagen (Denmark); Instituto de Biociências, Universidade Estadual Paulista, CP 510, 18618–970 Botucatu SP (Brazil); Calabresi, Marcos F.; Quini, Caio; Matos, Juliana F.; Miranda, José R.A.; Saeki, Margarida J. [Instituto de Biociências, Universidade Estadual Paulista, CP 510, 18618–970 Botucatu SP (Brazil); Bordallo, Heloisa N. [Niels Bohr Institute, University of Copenhagen, DK-2100 Copenhagen (Denmark)

    2015-03-01

    Alternate Current Biosusceptometry (ACB) is a promising bio-magnetic method, radiation free and easily performed used for gastric emptying exams. Due to development on its sensitivity level, interesting nature, noninvasiveness and low cost it has attracted a lot of attention. In this work, magnetic nanoparticles of Mn–Zn ferrite as well as dextrose-modified nanoparticles were synthesized to be used as possible tracers in ACB gastric emptying exams. In addition, a magnetic muco-adhesive gel was obtained by modifying the ferrite nanoparticles with cellulose. Based on in-vivo tests in rats, we show that the pure ferrite nanoparticles, whose isoelectric point was found to be at pH = 3.2, present a great sensitivity to pH variations along the gastrointestinal tract, while the reduction of the isoelectric point by the dextrose modification leads to suitable nanoparticles for rapid gastric emptying examinations. On the other hand, the in-vivo tests show that the muco-adhesive cellulose gel presents substantial stomach adhesion and is a potential drug delivery system easily traceable by the ACB system.

  18. Flexible, highly graphitized carbon aerogels based on bacterial cellulose/lignin: Catalyst-free synthesis and its application in energy storage devices

    KAUST Repository

    Xu, Xuezhu

    2015-04-15

    Currently, most carbon aerogels are based on carbon nanotubes (CNTs) or graphene, which are produced through a catalyst-assisted chemical vapor deposition method. Biomass based organic aerogels and carbon aerogels, featuring low cost, high scalability, and small environmental footprint, represent an important new research direction in (carbon) aerogel development. Cellulose and lignin are the two most abundant natural polymers in the world, and the aerogels based on them are very promising. Classic silicon aerogels and available organic resorcinol-formaldehyde (RF) or lignin-resorcinol-formaldehyde (LRF) aerogels are brittle and fragile; toughening of the aerogels is highly desired to expand their applications. This study reports the first attempt to toughen the intrinsically brittle LRF aerogel and carbon aerogel using bacterial cellulose. The facile process is catalyst-free and cost-effective. The toughened carbon aerogels, consisting of blackberry-like, core-shell structured, and highly graphitized carbon nanofibers, are able to undergo at least 20% reversible compressive deformation. Due to their unique nanostructure and large mesopore population, the carbon materials exhibit an areal capacitance higher than most of the reported values in the literature. This property makes them suitable candidates for flexible solid-state energy storage devices. Besides energy storage, the conductive interconnected nanoporous structure can also find applications in oil/water separation, catalyst supports, sensors, and so forth. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Synthesis and electrospinning carboxymethyl cellulose lithium (CMC-Li) modified 9,10-anthraquinone (AQ) high-rate lithium-ion battery.

    Science.gov (United States)

    Qiu, Lei; Shao, Ziqiang; Liu, Minglong; Wang, Jianquan; Li, Pengfa; Zhao, Ming

    2014-02-15

    New cellulose derivative CMC-Li was synthesized, and nanometer CMC-Li fiber was applied to lithium-ion battery and coated with AQ by electrospinning. Under the protection of inert gas, modified AQ/carbon nanofibers (CNF)/Li nanometer composite material was obtained by carbonization in 280 °C as lithium battery anode materials for the first time. The morphologies and structures performance of materials were characterized by using IR, (1)H NMR, SEM, CV and EIS, respectively. Specific capacity was increased from 197 to 226.4 mAhg(-1) after modification for the first discharge at the rate of 2C. Irreversible reduction reaction peaks of modified material appeared between 1.5 and 1.7 V and the lowest oxidation reduction peak of the difference were 0.42 V, the polarization was weaker. Performance of cell with CMC-Li with the high degree of substitution (DS) was superior to that with low DS. Cellulose materials were applied to lithium battery to improve battery performance by electrospinning. Copyright © 2013 Elsevier Ltd. All rights reserved.

  20. Bio-rational design of photosystem Ⅱ inhibitors (Ⅷ)——Molecular design, synthesis and inhibitory activity of acrylates (acrylamides)

    Institute of Scientific and Technical Information of China (English)

    刘华银; 沙印林; 谭惠芬; 杨华铮; 来鲁华

    1999-01-01

    Molecular modeling of acrylates (acrylamides) with D1 protein of Pisum sativum is presented. Studies show that the binding force mainly includes H-bond interaction, Van der Waals and π-ring stacking interaction. It was found that SER 268 in D1 protein might be an important binding site. It is important for high inhibitory activity of compounds whether an electronegative atom in alkyl of ester linkage could make H-bond interaction with SER 268 in D1 protein. Thus some new acrylates (acrylamides) were designed and synthesized, Bioassay indicated that these new compounds showed expected Hill reaction inhibitory activity.

  1. Synthesis, antiinflammatory and HIV-1 integrase inhibitory activities of 1,2-bis[5-thiazolyl]ethane-1,2-dione derivatives

    Directory of Open Access Journals (Sweden)

    Franklin P

    2009-01-01

    Full Text Available Based on principles of pharmacophore delineation and drug designing, compounds containing diketofunctionallity namely 1,2-bis[5-thiazolyl]ethane-1,2-diones were designed and synthesized as antiinflammatory agents. The compounds were evaluated in carrageenan-induced rat-paw edema method. G-3, G-6, G-17, G-20, G-23, G-22, L-708 and 906 showed good antiinflammatory activity. In addition as diketo functionality containing compounds are reported to have HIV-1 integrase inhibitory property, and these compounds contains diketo functionality, so these compounds were screened in assay for HIV-1 integrase inhibition. Few compounds showed weak HIV-1 integrase Inhibitory activity.

  2. 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.

  3. 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.

  4. High-yield production of extracellular type-I cellulose by the cyanobacterium Synechococcus sp. PCC 7002

    OpenAIRE

    Zhao, Chi; Li,Zhongkui; Li, Tao; Zhang, Yingjiao; Bryant, Donald A.; Zhao, Jindong

    2015-01-01

    Cellulose synthase, encoded by the cesA gene, is responsible for the synthesis of cellulose in nature. We show that the cell wall of the cyanobacterium Synechococcus sp. PCC 7002 naturally contains cellulose. Cellulose occurs as a possibly laminated layer between the inner and outer membrane, as well as being an important component of the extracellular glycocalyx in this cyanobacterium. Overexpression of six genes, cmc–ccp–cesAB–cesC–cesD–bgl, from Gluconacetobacter xylinus in Synechococcus s...

  5. Transgene silencing of sucrose synthase in alfalfa (Medicago sativa L.) stem vascular tissue suggests a role for invertase in cell wall cellulose synthesis.

    Science.gov (United States)

    Samac, Deborah A; Bucciarelli, Bruna; Miller, Susan S; Yang, S Samuel; O'Rourke, Jamie A; Shin, Sanghyun; Vance, Carroll P

    2015-12-01

    Alfalfa (Medicago sativa L.) is a widely adapted perennial forage crop that has high biomass production potential. Enhanced cellulose content in alfalfa stems would increase the value of the crop as a bioenergy feedstock. We examined if increased expression of sucrose synthase (SUS; EC 2.4.1.13) would increase cellulose in stem cell walls. Alfalfa plants were transformed with a truncated alfalfa phosphoenolpyruvate carboxylase gene promoter (PEPC7-P4) fused to an alfalfa nodule-enhanced SUS cDNA (MsSUS1) or the β-glucuronidase (GUS) gene. Strong GUS expression was detected in xylem and phloem indicating that the PEPC7-P4 promoter was active in stem vascular tissue. In contrast to expectations, MsSUS1 transcript accumulation was reduced 75-90 % in alfalfa plants containing the PEPC7-P4::MsSUS1 transgene compared to controls. Enzyme assays indicated that SUS activity in stems of selected down-regulated transformants was reduced by greater than 95 % compared to the controls. Although SUS activity was detected in xylem and phloem of control plants by in situ enzyme assays, plants with the PEPC7-P4::MsSUS1 transgene lacked detectable SUS activity in post-elongation stem (PES) internodes and had very low SUS activity in elongating stem (ES) internodes. Loss of SUS protein in PES internodes of down-regulated lines was confirmed by immunoblots. Down-regulation of SUS expression and activity in stem tissue resulted in no obvious phenotype or significant change in cell wall sugar composition. However, alkaline/neutral (A/N) invertase activity increased in SUS down-regulated lines and high levels of acid invertase activity were observed. In situ enzyme assays of stem tissue showed localization of neutral invertase in vascular tissues of ES and PES internodes. These results suggest that invertases play a primary role in providing glucose for cellulose biosynthesis or compensate for the loss of SUS1 activity in stem vascular tissue.

  6. 以纤维素为模板制备多孔SiO2棒%Synthesis of Mesoporous Silica Nanorod by Using the Cellulose as Template

    Institute of Scientific and Technical Information of China (English)

    张奎; 刘春华; 王平华; 范保林; 屈龙

    2011-01-01

    以2-溴丁酰溴与羟乙基纤维素的酯化产物为原子转移自由基(ATRP)聚合的天分子引发剂,在60℃引发甲基丙烯酸-N,N-二甲氨基乙酯(DMAEMA)聚合,再将PDMAEMA接枝到纤维素上.以此作为模板,在其水溶液中搅拌加入前驱体正硅酸乙酯(TEOS),水解产生二氧化硅凝胶并吸附在模板上,形成二氧化硅棒,通过红外光谱(FT-IR),热重分析(TGA)和透射电镜(TEM)对产物的结构、组成进行了表征.研究了pH值、TEOS用量、水解时间对二氧化硅棒形态的影响.实验结果表明,在pH=4,TEOS浓度为10mg/mL时,水解24 h~36 h,可以获得较好的棒状结构.%Cellulose was acylated with 2-bromobutyrylbromide at ambient temperature in ionic liquid (RTIL), 1allyi-3-methylimidazolium chloride, giving polyfunctional macroinitiators for atom transfer radical polymerization (ATRP). Copolymers were obtained via ATRP of N, N-dimethylamino-2-ethyl methacrylate (DMAEMA) with CuBr/pentamethyldiethylenetriamine (PMDETA) as catalyst and N, N-dimethylformamide (DMF) as solvent at 60 ℃. The resultant Cellulose-graft-poly (N, N-dimethylamino-2-ethyl methacrylate) (cellulose-g-PDMAEMA) was dissolved in distilled water under stirring. Mesoporous silica nanotubes were synthesized under mild conditions by applying conventional sol gel routes using tetraethyl orthosilicate (TEOS) as the precursors. The results were confirmed via FT-IR, TGA and TEM. The effect of the pH value, the concentration of TEOS and polycondensation time on the morphology of silicarod was studied. The results show that the desirable morphology of silicarod can be obtained from polycondensation of TEOS in aqueous solution with concentration of 10 mg/mL at pH= 4 for 24 h~36 h.

  7. Synthesis and characterization of superabsorbent polymer prepared by radiation-induced graft copolymerization of acrylamide onto carboxymethyl cellulose for controlled release of agrochemicals

    Science.gov (United States)

    Hemvichian, Kasinee; Chanthawong, Auraruk; Suwanmala, Phiriyatorn

    2014-10-01

    Superabsorbent polymer (SAP) was synthesized by radiation-induced grafting of acrylamide (AM) onto carboxymethyl cellulose (CMC) in the presence of a crosslinking agent, N,N‧-methylenebisacrylamide (MBA). The effects of various parameters, such as dose, the amount of CMC, AM, MBA and ionic strength on the swelling ratio were investigated. In order to evaluate its controlled release potential, SAP was loaded with potassium nitrate (KNO3) as an agrochemical model and its potential for controlled release of KNO3 was studied. The amount of released KNO3 was analyzed by an inductively coupled plasma mass spectrometry (ICP-MS). The results from controlled release experiment agreed very well with the results from swelling experiment. The synthesized SAP was characterized by Fourier transform infrared spectroscopy (FTIR) and thermogravimetric analysis (TGA). The obtained SAP exhibited a swelling ratio of 190 g/g of dry gel.

  8. 细菌纤维素的合成及其发酵培养改性%Synthesis of Bacterial Cellulose and the Modification of the Fermentation Medium

    Institute of Scientific and Technical Information of China (English)

    苏文萍; 王淑芳; 曹名锋; 孙秀梅; 李保宾; 解慧; 王利华; 宋存江

    2012-01-01

    分离到一株产细菌纤维素(Bacterial Cellulose,BC)的细菌,通过菌体形态、16S rRNA基因序列同源性分析鉴定,该菌株为葡糖醋杆菌,命名为Gluconacetobacter sp.SC-01.通过正交试验确定最佳培养基配方为4%甘露醇、1%玉米浆干粉、0.27% Na2HPO4、0.115%柠檬酸和0.025% MgSO4(pH 4.0).热失重分析表明,BC热失重速率最快时的温度为365 C.将海藻酸钠(sodium alginate ALG)、羧甲基纤维素(carboxymethyl cellulose CMC)、聚谷氨酸(polyglutamic acid PGA)、壳聚糖(chitosan CS)、聚乙烯醇(polyvinyl alcohol PVA)分别加入到发酵生产BC培养基中进行BC的发酵法合成,结果发现除CS外,ALG,CMC,PGA或PVA的加入均可提高BC的产量(最高产量达5.5 g/L)和含水量(最高含水率达99.5%).选取未改性的BC及添加了0.5%ALG、1% PGA、1.5% CMC的改性BC作为培养3T3细胞的基质材料,实验结果表明,添加了0.5% ALG的改性BC最适于3T3细胞生长,因而具有更好的生物相容性.%A strain being able to synthesize bacterial cellulose (BC) was isolated from a putrid fruit. It was classified and named as Gluconacetobacter sp. SC-01 by the morphological characteristics and 16S rRNA gene sequence analysis. The fermentation conditions were investigated by the orthogonal test. The optimized medium (pH 4. 0) contained mannitol 4%, corn steep powder 1%, NazHPO4 0. 27%, citric acid 0. 115% and MgSO4 0. 025%. Thermo-gravi-metric analysis(TGA)showed that the temperature for the fastest rate of thermal decomposition of BC was 365 C. Sodium alginate (ALG), carboxymethyl cellulose (CMC), poly-glu-tamic acid (PGA), chitosan (CS) or polyvinyl alcohol (PVA) was added to the fermentation medium separately when synthesizing BC by fermentation. It was found that the addition of some ALG, CMC, PGA, or PVA (CS excluded) can increase the production (the maximum yield was 5. 5 g/L) and water content (the highest water content was 99. 5%) of BC. Adding 0. 5% ALG,1

  9. 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%).

  10. Pro-inflammatory cytokine TNF-α is a key inhibitory factor for lactose synthesis pathway in lactating mammary epithelial cells.

    Science.gov (United States)

    Kobayashi, Ken; Kuki, Chinatsu; Oyama, Shoko; Kumura, Haruto

    2016-01-15

    Lactose is a milk-specific carbohydrate synthesized by mammary epithelial cells (MECs) in mammary glands during lactation. Lactose synthesis is downregulated under conditions causing inflammation such as mastitis, in which MECs are exposed to high concentrations of inflammatory cytokines. In this study, we investigated whether inflammatory cytokines (TNF-α, IL-1β, and IL-6) directly influence the lactose synthesis pathway by using two types of murine MEC culture models: the monolayer culture of MECs to induce lactogenesis; and the three-dimensional culture of MECs surrounded by Matrigel to induce reconstitution of the alveolar structure in vitro. TNF-α caused severe down-regulation of lactose synthesis-related genes concurrently with the degradation of glucose transporter 1 (GLUT1) from the basolateral membranes in MECs. IL-1β also caused degradation of GLUT1 along with a decrease in the expression level of β-1,4-galactosylransferase 3. IL-6 caused both up-regulation and down-regulation of the expression levels of lactose synthesis-related genes in MECs. These results indicate that TNF-α, IL-1β, and IL-6 have different effects on the lactose synthesis pathway in MECs. Furthermore, TNF-α triggered activation of NFκB and inactivation of STAT5, suggesting that NFκB and STAT5 signaling pathways are involved in the multiple adverse effects of TNF-α on the lactose synthesis pathway.

  11. Synthesis and evaluation of xanthine oxidase inhibitory and antioxidant activities of 2-arylbenzo[b]furan derivatives based on salvianolic acid C.

    Science.gov (United States)

    Tang, Hong-Jin; Zhang, Xiao-Wei; Yang, Lin; Li, Wei; Li, Jia-Huang; Wang, Jin-Xin; Chen, Jun

    2016-11-29

    Xanthine oxidase (XO) is the key enzyme in humans which is related to a variety of diseases such as gout, hyperuricemia and cardiovascular diseases. In this work, a series of 2-arylbenzo[b]furan derivatives were synthesized based on salvianolic acid C, and they were evaluated for xanthine oxidase inhibitory and antioxidant activities. Compounds 5b, 6a, 6e and 6f showed potent xanthine oxidase inhibitory activities with IC50 values ranging from 3.99 to 6.36 μM, which were comparable with that of allopurinol. Lineweaver-Burk plots analysis revealed that the representative derivative 6e could bind to either xanthine oxidase or the xanthine oxidase-xanthine complex, which exhibited a mixed-type competitive mechanism. A DPPH radical scavenging assay showed most of the hydroxyl-functionalized 2-arylbenzo[b]furan derivatives possessed the potent antioxidant activity, which was further validated on LPS-stimulated RAW 264.7 macrophages model. The structure-activity relationships were preliminary analyzed and indicated that the structural skeleton of 2-arylbenzo[b]furan and phenolic hydroxyl groups played an important role in maintaining xanthine oxidase inhibitory effect and antioxidant property for the series of derivatives. Meanwhile, molecular docking studies were performed to further confirm the structure-activity relationships and investigate the proposed binding mechanisms of compounds 5d, 6d and 10d binding to the protein.

  12. Synthesis of the iron-molybdenum cofactor of nitrogenase is inhibited by a low-molecular-weight metabolite of Klebsiella pneumoniae.

    Science.gov (United States)

    Downs, D M; Ludden, P W; Shah, V K

    1990-10-01

    The in vitro synthesis of the iron-molybdenum cofactor nitrogenase was inhibited by a low-molecular-weight factor. This inhibitory factor was present in the membrane extracts of wild-type and nif mutant strains of Klebsiella pneumoniae that were grown under conditions that either repressed or derepressed nitrogenase expression. In vitro, the inhibition was specific for the NifB protein. Addition of this factor to K. pneumoniae cells at various times during nif derepression decreased nitrogenase activity, presumably through inhibition of iron-molybdenum cofactor synthesis. The inhibitor was purified by solvent extraction and chromatography on DEAE-cellulose, silica gel, and aluminum oxide columns.

  13. Brassinosteroids can regulate cellulose biosynthesis by controlling the expression of CESA genes in Arabidopsis

    OpenAIRE

    Xie, Liqiong; Yang, Cangjing; Wang, Xuelu

    2011-01-01

    The phytohormones, brassinosteroids (BRs), play important roles in regulating cell elongation and cell size, and BR-related mutants in Arabidopsis display significant dwarf phenotypes. Cellulose is a biopolymer which has a major contribution to cell wall formation during cell expansion and elongation. However, whether BRs regulate cellulose synthesis, and if so, what the underlying mechanism of cell elongation induced by BRs is, is unknown. The content of cellulose and the expression levels o...

  14. 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.

  15. Facile synthesis of Ni(OH)2/graphene/bacterial cellulose paper for large areal mass, mechanically tough and flexible supercapacitor electrodes

    Science.gov (United States)

    Ma, Lina; Liu, Rong; Liu, Li; Wang, Fang; Niu, Haijun; Huang, Yudong

    2016-12-01

    A general approach toward flexible supercapacitor electrode based on metal hydroxide is developed, which offers ultrahigh areal capacitance without compromising their gravimetric capacitance and mechanical properties. As a prototype, bendable freestanding film is fabricated by coating graphene (RGO)-wrapped flowery Ni(OH)2 on bacterial cellulose (BC) with a rational combination of hydrothermal method and filtration technology. This as-assembled hierarchically structured flexible electrode is characterized by remarkable areal capacitance of 10.44 F cm-2 (877.1 F g-1) at a large mass loading of 11.9 mg cm-2, excellent cycling stability with 93.6% capacitance retention after 15,000 cycles, high flexibility including bending to arbitrary angles (even 180°) and prominent tensile strength (48.8 MPa at wet state). Furthermore, it is hoped that the typical method can be applied for realizing other metal oxide/hydroxide flexible electrodes. The simple, high scalable, low-cost, and general strategy could open up new opportunities for flexible energy storage devices.

  16. Synthesis of polycaprolactone-grafted microfibrillated cellulose for use in novel bionanocomposites--influence of the graft length on the mechanical properties.

    Science.gov (United States)

    Lönnberg, Hanna; Larsson, Karolina; Lindström, Tom; Hult, Anders; Malmström, Eva

    2011-05-01

    In the present work, microfibrillated cellulose (MFC) made from bleached sulfite softwood dissolving pulp was utilized to reinforce a poly(ε-caprolactone) (PCL) biopolymer matrix. To improve the dispersibility of the hydrophilic MFC in the nonpolar matrix and the interfacial adhesion in the composite material, we covalently grafted the MFC with PCL via ring-opening polymerization (ROP) of ε-caprolactone (ε-CL). To be able to investigate the effect of the PCL graft length on the mechanical properties of the composite material, we performed ROP to different molecular weights of the grafts. Bionanocomposites containing 0, 3, and 10 wt % MFC were prepared via hot pressing using both unmodified and PCL grafted MFC (MFC-g-PCL) as reinforcement. PCL grafting resulted in improved dispersion of the MFC in a nonpolar solvent and in the PCL matrix. The mechanical testing of the biocomposites showed an improvement in the mechanical properties for the PCL grafted MFC in comparison to ungrafted MFC. It was also shown that there was an impact on the mechanical properties with respect to the PCL graft lengths, and the strongest biocomposites were obtained after reinforcement with MFC grafted with the longest PCL graft length.

  17. Synthesis and adsorption properties of polymer-mesoporous SiO2 nanocomposite based on cellulose biomass via self-assembly

    Science.gov (United States)

    Tao, Jin; Xiong, Jiaqing; Jiao, Chenlu; Chen, Yuyue; Lin, Hong

    2017-06-01

    The present work describes the fabrication of an amino hyperbranched polymer (AHP) functionalized mesoporous SiO2 nanocomposite based on cellulose biomass substrate through self-assembly method, obtaining a multi-functional hybrid composite (AM-cotton) as adsorbent for dye pollutions from aqueous medium. Specifically, polymer-functionalized mesoporous SiO2 nanoparticles (AMSNs) was obtained by covalently graft of AHP onto carboxyl-functionalized mesoporous silica nanoparticles (CMSNs) which were prepared via one-pot co-condensation. Subsequently, owing to electrostatic interaction between interfaces, AM-cotton fibers were fabricated via self-assembly of amino coated AMSNs on the surface of anion-modified cotton fiber (AN-cotton). Due to considerate versatile functional groups from hyperbranched polymer on nano-sized mesoporous silica with large surface area per unit mass, the functional fiber AM-cotton exhibits excellent adsorption capabilities for anionic (Congo red, CR) and cationic (Methylene blue, MB) dye pollutant with maximum of 195 mg/g for CR and 144 mg/g for MB, respectively.

  18. Synthesis and Characterization of Uniform Spherical Nanoporous TiO2 Aerogel Templated by Cellulose Alcohol-Gel with Enhanced Photocatalytic Activity

    Directory of Open Access Journals (Sweden)

    Zhiming Liu

    2016-01-01

    Full Text Available The spherical nanoporous TiO2 aerogels were prepared by a simple ethanol-thermal method, using spherical cellulose alcohol-gel as the template. The morphology, crystalline structure, pore size, specific surface area, and the photocatalytic activity of obtained TiO2 aerogel were separately characterized by scanning electron microscopy (SEM, transmission electron microscopy (TEM, X-ray diffraction (XRD, X-ray photoelectron spectroscopy (XPS, N2 adsorption-desorption isotherms, and double beam UV-VIS spectrophotometer. The characteristics of TiO2 aerogels presented uniform sphere shape, good internal structural morphology, high specific surface area (ranging from 111.88 to 149.95 m2/g, and good crystalline anatase phase. Moreover, methyl orange dye was used as the target pollutant to characterize the photocatalytic activities and the adsorption performance. The photocatalytic experiment shows that the obtained spherical TiO2 aerogels had a higher degradation ratio of 92.9% on methyl orange dye compared with aspherical TiO2 aerogels prepared from other concentrations of tetrabutyl orthotitanate (TBOT.

  19. Synthesis of New Tricyclic and Tetracyclic Fused Coumarin Sulfonate Derivatives and Their Inhibitory Effects on LPS-Induced Nitric Oxide and PGE2 Productions in RAW 264.7 Macrophages: Part 2.

    Science.gov (United States)

    El-Gamal, Mohammed I; Lee, Woo-Seok; Shin, Ji-Sun; Oh, Chang-Hyun; Lee, Kyung-Tae; Choi, Jungseung; Myoung, Nohsun; Baek, Daejin

    2016-11-01

    The synthesis of a new series of 21 fused coumarin derivatives is described, and the biological evaluation of their in vitro antiinflammatory effects as inhibitors of lipopolysaccharide (LPS)-induced nitric oxide (NO) and prostaglandin E2 (PGE2 ) production in RAW 264.7 macrophages. The target compounds 1a-u were first tested for cytotoxicity to determine a non-toxic concentration for antiinflammatory screening, so that the inhibitory effects against NO and PGE2 production would not be caused by cytotoxicity. Compounds 1f and 1p were the most active PGE2 inhibitors with IC50 values of 0.89 and 0.95 µM, respectively. Western blot and cell-free COX-2 screening showed that their effects were due to inhibition of both COX-2 protein expression and COX-2 enzyme activity. Their IC50 values against the COX-2 enzyme were 0.67 and 0.85 µM, respectively, which is more potent than etoricoxib. The selectivity indexes of compounds 1f and 1p against COX-2 compared to COX-1 were 41.1 and 42.5, respectively. Compound 1f showed strong inhibitory effects at 5 µM concentration on COX-2 mRNA expression in LPS-induced RAW 264.7 macrophages. Moreover, the tricyclic compounds 1l and 1n as well as the tetracyclic analog 1u were the most potent NO inhibitors, with one-digit micromolar IC50 values. They showed dose-dependent inhibition of inducible nitric oxide synthase (iNOS) protein expression. The tetracyclic derivative 1u was the most potent inhibitor of NO production. It also exhibited a strong inhibitory effect on iNOS mRNA expression in LPS-induced RAW 264.7 macrophages.

  20. Synthesis and HIV-1 RT inhibitory action of novel (4/6-substituted benzo[d]thiazol -2-yl)thiazolidin-4-ones. Divergence from the non-competitive inhibition mechanism.

    Science.gov (United States)

    Pitta, Eleni; Geronikaki, Athina; Surmava, Sofiko; Eleftheriou, Phaedra; Mehta, Vaibhav P; Van der Eycken, Erik V

    2013-02-01

    Reverse transcriptase (RT) inhibitors play a major role in the therapy of human immunodeficiency virus type 1 (HIV-1) infection. Although, many compounds are already used as anti-HIV drugs, research on development of novel inhibitors continues, since drug resistant strains appear because of prolonged therapy. In this paper, we present the synthesis and evaluation of HIV-1 RT inhibitory action of eighteen novel (4/6-halogen/MeO/EtO-substituted benzo[d]thiazol-2-yl)thiazolidin-4-ones. The two more active compounds (IC50 : 0.04 µM and 0.25 µM) exhibited better inhibitory action than the reference compound, nevirapine. Docking analysis supports a stable binding of the most active derivative to the allosteric centre of RT. Kinetic analysis of two of the most active compounds indicate an uncompetitive inhibition mode. This is a desired characteristic, since mutations that affect activity of traditional non-competitive NNRTIs may not affect activity of compounds of this series. Interestingly, the less active derivatives (IC50 > 40 µM) exhibit a competitive mode of action.

  1. Inhibitory effects of salidroside and paeonol on tyrosinase activity and melanin synthesis in mouse B16F10 melanoma cells and ultraviolet B-induced pigmentation in guinea pig skin.

    Science.gov (United States)

    Peng, Li-Hua; Liu, Shuai; Xu, Shen-Yao; Chen, Lei; Shan, Ying-Hui; Wei, Wei; Liang, Wen-Quan; Gao, Jian-Qing

    2013-09-15

    Salidroside, the major active component of Rhodiola rosea, a herb with antioxidant, free radical scavenging and tyrosinase inhibitory effects, has been recently reported in protecting the kerationcytes from the UV radiation, suggesting the potential of this component in depigmentation. Paeonol is isolated from Moutan Cortex Radicis with anti-inflammation/microbial activities, was reported to induce the down-regulation of microphthalmia-associated transcription factor and subsequently tyrosinase. To testify the potential of these compounds as melanin formation inhibitors for hyperpigmentation therapy, the influence of salidroside and paeonol on pigmentation was investigated. With arbutin as a positive control, salidroside and paeonol were evaluated for their inhibitory effect on the cell viability, tyrosinase activity and melanin synthesis in B16F10 melanoma cells, as well as their effects in UVB-induced hyperpigmentation in brown guinea pig skins. It was demonstrated that the significant inhibition of salidroside (33.0%) and paeonol (22.2-30.9%) on the tyrosinase activity is slightly lower than that of arbutin (18.4-44.7%). However, salidroside exhibited the dose-dependent inhibition (30.6-42.0%) in melanin synthesis at a low concentration of 100 μM, paeonol and arbutin expressed inhibition rates of 27.4-37.2% and 25.8-45.6% within 500-1000 μM. The in vivo topical application of these compounds was demonstrated to obviously decrease the hyperpigmentation on UVB stimulated guinea pig skin. This study provided the original evidence for the salidroside and paeonol as therapeutic agents for pigmentation disorder and skin lightening, with further clinical investigation of these compounds in the field of depigmentation was suggested. Copyright © 2013 Elsevier GmbH. All rights reserved.

  2. Negative results of growing titania nanotubes on cellulose nanocrystals - Effect of hydrothermal reaction

    Science.gov (United States)

    Chamakh, Mariem Mohamed; Ponnamma, Deepalekshmi; Al-Maadeed, Mariam Al Ali

    Titania nanotubes (TiO2 nanotubes or TNT) are grown hydrothermally on cellulose nanocrystals (CNC) synthesized from microcrystalline cellulose. It is observed that the CNC are lost during synthesis due to its low thermal stability. This negative result of metal growth on CNC and its influence on thermal degradation are reported here.

  3. Inhibitory Role of Greatwall-Like Protein Kinase Rim15p in Alcoholic Fermentation via Upregulating the UDP-Glucose Synthesis Pathway in Saccharomyces cerevisiae.

    Science.gov (United States)

    Watanabe, Daisuke; Zhou, Yan; Hirata, Aiko; Sugimoto, Yukiko; Takagi, Kenichi; Akao, Takeshi; Ohya, Yoshikazu; Takagi, Hiroshi; Shimoi, Hitoshi

    2015-10-23

    The high fermentation rate of Saccharomyces cerevisiae sake yeast strains is attributable to a loss-of-function mutation in the RIM15 gene, which encodes a Greatwall-family protein kinase that is conserved among eukaryotes. In the present study, we performed intracellular metabolic profiling analysis and revealed that deletion of the RIM15 gene in a laboratory strain impaired glucose-anabolic pathways through the synthesis of UDP-glucose (UDPG). Although Rim15p is required for the synthesis of trehalose and glycogen from UDPG upon entry of cells into the quiescent state, we found that Rim15p is also essential for the accumulation of cell wall β-glucans, which are also anabolic products of UDPG. Furthermore, the impairment of UDPG or 1,3-β-glucan synthesis contributed to an increase in the fermentation rate. Transcriptional induction of PGM2 (phosphoglucomutase) and UGP1 (UDPG pyrophosphorylase) was impaired in Rim15p-deficient cells in the early stage of fermentation. These findings demonstrate that the decreased anabolism of glucose into UDPG and 1,3-β-glucan triggered by a defect in the Rim15p-mediated upregulation of PGM2 and UGP1 redirects the glucose flux into glycolysis. Consistent with this, sake yeast strains with defective Rim15p exhibited impaired expression of PGM2 and UGP1 and decreased levels of β-glucans, trehalose, and glycogen during sake fermentation. We also identified a sake yeast-specific mutation in the glycogen synthesis-associated glycogenin gene GLG2, supporting the conclusion that the glucose-anabolic pathway is impaired in sake yeast. These findings demonstrate that downregulation of the UDPG synthesis pathway is a key mechanism accelerating alcoholic fermentation in industrially utilized S. cerevisiae sake strains.

  4. Optimization, synthesis, and characterization of coaxial electrospun sodium carboxymethyl cellulose-graft-methyl acrylate/poly(ethylene oxide) nanofibers for potential drug-delivery applications.

    Science.gov (United States)

    Esmaeili, Akbar; Haseli, Mahsa

    2017-10-01

    In this study, nanofiber drug carriers were fabricated via coaxial electrospinning, using a new, degradable core-shell nanofiber drug carrier fabricated via coaxial electrospinning. Fabrication of the shell was carried out by graft polymerization of sodium carboxymethyl cellulose (NaCMC) with methyl acrylate (TCMC) and poly(ethylene oxide) (PEO). Tetracycline hydrochloride (TCH) was used as a drug model incorporated within the nanofibers as the core, and their performance as a drug carrier scaffold was evaluated. The loading of TCH within PEO nanofibers and the loading of TCH within the TCMC nanofibers were characterized via different techniques. The structure morphology of the obtained nanofibers was viewed under scanning electron microscope (SEM). The changes in the polymer structure before and after grafting and confirmation of incorporation of the drug in the fibers were characterized by Fourier transform infrared spectroscopy (FT-IR). Response surface methodology (RSM) was applied to predict the optimum conditions for fabrication of the nanofibers. The cell viability of the optimized samples was assessed with 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The TCH loaded into the optimized core-shell sample of TCMC 3% (w/v)/PEO 1% (w/v) had a smooth and beadless morphology with a diameter of 86.12nm, slow and sustained drug release, and excellent bactericidal activity against a wide range of bacteria. This shows promise for use as an antibacterial material in such applications as tissue engineering and pharmaceutical science. Copyright © 2017 Elsevier Ltd. All rights reserved.

  5. Molecular characterization of a dual inhibitory and mutagenic activity of 5-fluorouridine triphosphate on viral RNA synthesis. Implications for lethal mutagenesis.

    Science.gov (United States)

    Agudo, Rubén; Arias, Armando; Pariente, Nonia; Perales, Celia; Escarmís, Cristina; Jorge, Alberto; Marina, Anabel; Domingo, Esteban

    2008-10-10

    The basis for a dual inhibitory and mutagenic activity of 5-fluorouracil (5-FU) on foot-and-mouth disease virus (FMDV) RNA replication has been investigated with purified viral RNA-dependent RNA polymerase (3D) in vitro. 5-Fluorouridine triphosphate acted as a potent competitive inhibitor of VPg uridylylation, the initial step of viral replication. Peptide analysis by mass spectrometry has identified a VPg fragment containing 5-fluorouridine monophosphate (FUMP) covalently attached to Tyr3, the amino acid target of the uridylylation reaction. During RNA elongation, FUMP was incorporated in the place of UMP or CMP by FMDV 3D, using homopolymeric and heteropolymeric templates. Incorporation of FUMP did not prevent chain elongation, and, in some sequence contexts, it favored misincorporations at downstream positions. When present in the template, FUMP directed the incorporation of AMP and GMP, with ATP being a more effective substrate than GTP. The misincorporation of GMP was 17-fold faster opposite FU than opposite U in the template. These results in vitro are consistent with the mutational bias observed in the mutant spectra of 5-FU-treated FMDV populations. The dual mutagenic and inhibitory activity of 5-fluorouridine triphosphate may contribute to the effective extinction of FMDV by 5-FU through virus entry into error catastrophe.

  6. Synthesis and monoamine oxidase inhibitory activities of some 3-(4-fluorophenyl)-5-aryl-n-substituted-4,5-dihydro-(1H)-pyrazole-1-carbothioamide derivatives.

    Science.gov (United States)

    Koç, G Ş; Tan, O U; Uçar, G; Yildirim, E; Erol, K; Palaska, E

    2014-11-01

    28 new 3-(4-fluorophenyl)-5-aryl-N-substituted-4,5-dihydro-1H-pyrazole-1-carbothioamide derivatives were synthesized and evaluated in vitro for their monoamine oxidase (MAO) A and B inhibitory activity and selectivity. The derivatives substituted by halogen on the fifth position of pyrazole ring, inhibited MAO-A enzyme with a high selectivity index. On the other hand, compounds substituted with 2-naphthyl inhibited MAO-B enzyme with a moderate selectivity index. Docking studies were done to highlight the interactions of the most active derivative with the active site of MAO-A. In addition, in vivo antidepressant and anxiolytic activities of the compounds having selective MAO-A inhibitory effects, were investigated by using Porsolt forced swimming and elevated plus-maze tests respectively. 3-(4-Fluorophenyl)-5-(4-chloro-phenyl)-N-allyl-4,5-dihydro-1H-pyrazole-1-carbothio-amide has antidepressant, 3-(4-fluorophenyl)-5-(4-chlorophenyl)-N-methyl-4,5-dihydro-1H-pyrazole-1-carbothioamide and 3-(4-fluoro-phenyl)-5-(4-bromophenyl)-N-ethyl-4,5-dihydro-1H-pyrazole-1-carbothioamide have anxiolytic activity.

  7. 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.

  8. Processing and characterization of natural cellulose fibers/thermoset polymer composites.

    Science.gov (United States)

    Thakur, Vijay Kumar; Thakur, Manju Kumari

    2014-08-30

    Recently natural cellulose fibers from different biorenewable resources have attracted the considerable attraction of research community all around the globe owing to their unique intrinsic properties such as biodegradability, easy availability, environmental friendliness, flexibility, easy processing and impressive physico-mechanical properties. Natural cellulose fibers based materials are finding their applications in a number of fields ranging from automotive to biomedical. Natural cellulose fibers have been frequently used as the reinforcement component in polymers to add the specific properties in the final product. A variety of cellulose fibers based polymer composite materials have been developed using various synthetic strategies. Seeing the immense advantages of cellulose fibers, in this article we discuss the processing of biorenewable natural cellulose fibers; chemical functionalization of cellulose fibers; synthesis of polymer resins; different strategies to prepare cellulose based green polymer composites, and diverse applications of natural cellulose fibers/polymer composite materials. The article provides an in depth analysis and comprehensive knowledge to the beginners in the field of natural cellulose fibers/polymer composites. The prime aim of this review article is to demonstrate the recent development and emerging applications of natural cellulose fibers and their polymer materials.

  9. Solubility of wood-cellulose in LiCl/DMAC solvent system

    Institute of Scientific and Technical Information of China (English)

    He Jing; Liu Zhu; Li Hua-yang; Wang Guo-hua; Pu Jun-wen

    2007-01-01

    A LiCl/DMAC solvent system was used to dissolve wood-cellulose with aims to broaden its application in preparing functional materials of modified wood-cellulose. We studied the dissolubility complexion of wood-cellulose in a LiCl/DMAC solvent system, made sure of the important function of LiCl in a cellulose solvent, and further confirmed its dissolution mechanism via the measurement of infrared spectra of soluble products. The study results are as follows: first, LiCl salts, which can form intermediate complexes with cellulose, have played an important role in the LiCl/DMAC solvent system, and their solubility performance is enhanced by reducing the hydrogen bond effect between cellulose molecules; second, the non-aqueous solvent system is a better method for dissolving wood-cellulose in homogenous phase. As found in infrared spectra, the absorption intensity of hydroxyl groups (broad peaks: 3,400 cm-1) decreased greatly in cellulose macromolecules. This is because the degree of association between the hydroxyl groups of cellulose macromolecules is reduced, due to the destruction of the hydrogen bonds. Lastly, wood-cellulose can be dissolved in a LiCl/DMAC solvent thoroughly and efficiently, and can provide a better solvent system for homogeneous synthesis in the preparation of new functional materials via modified wood-cellulose.

  10. 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 TEMPO‐mediated hypohalite oxidation. The alkyne groups, essential for the click reaction, were introduced into the surface of TEMPO‐ oxidized CNCs via carbodiimide‐mediated formation of an amide linkage between monomers carrying an amine functionality and carboxylic acid groups on the surface of the TEMPO‐oxidized CNCs. Finally, the reaction of surface‐modified TEMPO‐oxidized cellulose nanocrystals and azido‐bearing coumarin and anthracene monomers were carried out by means of a click chemistry, i.e., Copper(I‐catalyzed Azide‐Alkyne Cycloaddition (CuAAC to produce highly photo‐responsive and fluorescent cellulose nanoparticles. Most significantly, the installed coumarin and/or anthracene side‐chains were shown to undergo UV‐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 nano‐arrays with the potential of photo reversibility since these reactions are known to be reversible at varying wavelengths.

  11. Click chemistry inspired one-pot synthesis of 1,4-disubstituted 1,2,3-triazoles and their Src kinase inhibitory activity.

    Science.gov (United States)

    Kumar, Dalip; Reddy, V Buchi; Kumar, Anil; Mandal, Deendayal; Tiwari, Rakesh; Parang, Keykavous

    2011-01-01

    Two classes of 1,4-disubstituted 1,2,3-triazoles were synthesized using one-pot reaction of α-tosyloxy ketones/α-halo ketones, sodium azide, and terminal alkynes in the presence of aq PEG (1:1, v/v) using the click chemistry approach and evaluated for Src kinase inhibitory activity. Structure-activity relationship analysis demonstrated that insertion of C(6)H(5)- and 4-CH(3)C(6)H(4)- at position 4 for both classes and less bulkier aromatic group at position 1 in class 1 contribute critically to the modest Src inhibition activity (IC(50) = 32-43 μM) of 1,4-disubstituted 1,2,3-triazoles.

  12. Synthesis and Acetylcholinesterase Inhibitory Evaluation of 4-(1,3-Dioxoisoindolin-2-yl)-N-Phenyl Benzamide Derivatives as Potential Anti-Alzheimer Agents

    Science.gov (United States)

    Mohammadi-Farani, Ahmad; Soltani Darbandi, Samira; Aliabadi, Alireza

    2016-01-01

    Alzheimer᾽s disease is characterized by cognitive deficits, impaired long-term potentiation of learning and memory. A progressive reduction in cholinergic neurons in some areas of the brain such as cortex and hippocampus is related to the deficits in memory and cognitive function in Alzheimer’s disease (AD). In the current project a new series of phthalimide derivatives were synthesized. Phthalic anhydride was reacted with 4-aminobenzoic acid in the presence of triethylamine under reflux condition. Then, the obtained acidic derivative was utilized for preparation of final compounds via an amidation reaction through a carbodiimde coupling reaction. Anti-acetylcholinesterase activity of synthesized derivatives was assessed by Ellman᾽s test. Compound 4g in this series exhibited the highest inhibitory potency (IC50 = 1.1 ± 0.25 µM) compared to donepezil (IC50 = 0.41 ± 0.12 µM) as reference drug. PMID:27980565

  13. Structural and physico-mechanical characterization of bio-cellulose produced by a cell-free system.

    Science.gov (United States)

    Ullah, Muhammad Wajid; Ul-Islam, Mazhar; Khan, Shaukat; Kim, Yeji; Park, Joong Kon

    2016-01-20

    This study was aimed to characterize the structural and physico-mechanical properties of bio-cellulose produced through cell-free system. Fourier transform-infrared spectrum illustrated exact matching of structural peaks with microbial cellulose, used as reference. Field-emission scanning electron microscopy revealed that fibrils of bio-cellulose were thicker and more compact than microbial cellulose. The specific positions of peaks in the X-ray diffraction and nuclear magnetic resonance spectra indicated that bio-cellulose possessed cellulose II polymorphic structure. Bio-cellulose presented superior physico-mechanical properties than microbial cellulose. The water holding capacity of bio-cellulose and microbial cellulose were found to be 188.6 ± 5.41 and 167.4 ± 4.32 times their dry-weights, respectively. Tensile strengths and degradation temperature of bio-cellulose were 17.63 MPa and 352 °C, respectively compared to 14.71 MPa and 327 °C of microbial cellulose. Overall, the results indicated successful synthesis and superior properties of bio-cellulose that advocate its effectiveness for various applications.

  14. Cellulose and the Control of Growth Anisotropy

    Energy Technology Data Exchange (ETDEWEB)

    Tobias I. Baskin

    2004-04-01

    The authors research aims to understand morphogenesis, focusing on growth anisotropy, a process that is crucial to make organs with specific and heritable shapes. For the award, the specific aims were to test hypotheses concerning how growth anisotropy is controlled by cell wall structure, particularly by the synthesis and alignment of cellulose microfibrils, the predominant mechanical element in the cell wall. This research has involved characterizing the basic physiology of anisotropic expansion, including measuring it at high resolution; and second, characterizing the relationship between growth anisotropy, and cellulose microfibrils. Important in this relationship and also to the control of anisotropic expansion are structures just inside the plasma membrane called cortical microtubules, and the research has also investigated their contribution to controlling anisotropy and microfibril alignment. In addition to primary experimental papers, I have also developed improved methods relating to these objectives as well as written relevant reviews. Major accomplishments in each area will now be described.

  15. 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...

  16. 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.

  17. 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

  18. Synthesis and inhibitory evaluation of 3-linked imipramines for the exploration of the S2 site of the human serotonin transporter

    DEFF Research Database (Denmark)

    Brinkø, Anne; Larsen, Maja Thim; Koldsø, Heidi;

    2016-01-01

    report the synthesis of 3-position coupled imipramine ligands from clomipramine using a copper free Sonogashira reaction. Ligand design was inspired by results from docking and steered molecular dynamics simulations, and the ligands were utilized in a structure–activity relationship study...... of the positional relationship between the S1 and S2 sites. The computer simulations suggested that the S2 site does indeed exist although with lower affinity for imipramine than observed within the S1 site. Additionally, it was possible to dock the 3-linked imipramine analogs into positions which occupy the S1...

  19. 新型温敏羟丙基纤维素微凝胶的合成%SYNTHESIS OF NEW THERMOSENSITIVE MICROGEL FROM HYDROXYPROPYL CELLULOSE

    Institute of Scientific and Technical Information of China (English)

    吕丹崖; 王润雨; 关英; 张拥军

    2012-01-01

    Due to their better biocompatibility and biodegradability, microgels from natural polymers are preferable for applications in biomedical areas. Microgels have been synthesized from hydroxypropylcellulose (UPC), a thermosensitive cellulose ether, via various methods, however, none of the resultant products can be degraded completely, posing barriers for in vivo applications. Here a new method was developed to synthesize HPC microgel. HPC was first partially oxidized with sodium periodate to generate aldehyde functionalities. The introduction of aldehyde groups was confirmed by FTIR spectra. The oxidized HPC remains thermosensitive and its lower critical solution temperature (LCST) remained unchanged. When heated above the LCST, HPC chains aggregated into nanoparticles through hydrophobic interaction. The nanoparticles were then covalently crosslinked with adipic dihydrazide, as a result of the reaction between the aldehyde groups in HPC and the amino groups in the crosslinker. TEM study showed the microgel particles were round in shape with a size ranging from 100nm to 300nm. The microgel was thermosensitive, as indicated by its shrunken size and increased turbidity upon heating. Preliminary in vitro cytotoxicity assay showed no changes in cell viability and morphology in the presence of HPC microgel, suggesting the microgel synthesized here was not cytotoxinic. As both HPC and adipic dihydrazide were biodegradable, the new microgel was also expected to be biodegradable and may find applications in biomedical areas.%天然高分子具有良好的生物相容性和生物可降解性,因此用天然高分子制备的微凝胶更适合于生物医学领域的应用.羟丙基纤维素(HPC)是一种具有温度敏感性的纤维素衍生物,可通过不同的方法制备为微凝胶,然而现有方法制备的HPC微凝胶都不能完全降解.我们采用一种新方法制备HPC微凝胶.首先通过NaIO4处理将醛基引入HPC.红外光谱检测证明了醛基的生

  20. The Dictyostelium discoideum cellulose synthase: Structure/function analysis and identification of interacting proteins

    Energy Technology Data Exchange (ETDEWEB)

    Richard L. Blanton

    2004-02-19

    OAK-B135 The major accomplishments of this project were: (1) the initial characterization of dcsA, the gene for the putative catalytic subunit of cellulose synthase in the cellular slime mold Dictyostelium discoideum; (2) the detection of a developmentally regulated event (unidentified, but perhaps a protein modification or association with a protein partner) that is required for cellulose synthase activity (i.e., the dcsA product is necessary, but not sufficient for cellulose synthesis); (3) the continued exploration of the developmental context of cellulose synthesis and DcsA; (4) the isolation of a GFP-DcsA-expressing strain (work in progress); and (5) the identification of Dictyostelium homologues for plant genes whose products play roles in cellulose biosynthesis. Although our progress was slow and many of our results negative, we did develop a number of promising avenues of investigation that can serve as the foundation for future projects.

  1. 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-film-immobilized 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.

  2. Bacterial Cellulose From Rice Waste Water With Addition Chitosan, Glycerol, And Silver Nanoparticle

    Directory of Open Access Journals (Sweden)

    Eli Rohaeti

    2016-05-01

    Full Text Available This study aimed to prepare silver nanoparticles chemically, deposite silver nanoparticles on bacterial cellulose-chitosan-glycerol composite based rice waste water, as well as test the antibacterial activity of bacterial cellulose and its composite. Preparation of silver nanoparticles was conducted by chemical reduction of silver nitrate solution, as well as trisodium citrate as the reductor. Bacterial cellulose from rice waste water is fermented by the bacteria Acetobacter xylinum for 7 days. The dried bacterial cellulose was composited with chitosan and glycerol by immersion method on 2% of chitosan solution and 0.5% of glycerol solution. UV-Vis spectroscopy is used to determine the formation of silvernanoparticles and Particle Size Analyzer to test the size and particle size distribution. Characterization was conducted to bacterial cellulose and its composite included functional groups by FTIR, the mechanical properties by Tensile Tester, crystallinity by XRD, surface photograph by SEM, and antibacterial test against S. aureus and E. coli by the shake flask turbidimetry method. Silver nanoparticle characterization indicated that silver nanoparticles are formed at a wavelength of 421.80 nm, yellow, diameter particle size of 61.8 nm. SEM images showed that the surface of bacterial cellulose had deposited silver nanoparticles and antibacterial test showed an inhibitory effect of bacterial cellulose, bacterial cellulose-chitosan composite, and bacterial cellulose-chitosan-glycerol composite which are deposited silver nanoparticles against the growth of S. aureus and E. coli bacteria.

  3. 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.

  4. Synthesis, cytotoxic activity, and tubulin polymerization inhibitory activity of new pyrrol-2(3H)-ones and pyridazin-3(2H)-ones.

    Science.gov (United States)

    Abbas, Samar Hafez; Abuo-Rahma, Gamal El-Din A A; Abdel-Aziz, Mohamed; Aly, Omar M; Beshr, Eman A; Gamal-Eldeen, Amira M

    2016-06-01

    A series of new pyrrol-2(3H)-ones 4a-f and pyridazin-3(2H)-ones 7a-f were synthesized and characterized using different spectroscopic tools. Some of the tested compounds revealed moderate activity against 60 cell lines. The E form of the pyrrolones 4 showed good cytotoxic activity than both the Z form and the corresponding open amide form. Furthermore, the in vitro cytotoxic activity against HepG2 and MCF-7 cell lines revealed that compounds (E)4b, 6f and 7f showed good cytotoxic activity against HepG2 with IC50 values of 11.47, 7.11 and 14.80μM, respectively. Compounds (E)4b, 6f, 7d and 7f showed a pronounced inhibitory effect against cellular localization of tubulin. Flow cytometric analysis indicated that HepG2 cells treated with (E)4b showed a predominated growth arrest at the S-phase compared to that of G2/M-phase. Molecular modeling study using MOE® program indicated that most of the target compounds showed good binding of β-subunit of tubulin with the binding free energy (dG) values about -10kcal/mole.

  5. Non-enzymatic depolymerization of cotton cellulose by fungal mimicking metabolites

    DEFF Research Database (Denmark)

    Hastrup, Anne Christine Steenkjær; Howell, Caitlin; Jensen, Bo

    2011-01-01

    peroxide, iron, and oxalic acid. The former two are involved in the Fenton reaction in which they react to form hydroxyl radicals, which cause an accelerated depolymerization in cotton cellulose. We found the same reaction to be caused by both iron Fe3+ and Fe2+. A 10 mM oxalic acid solution showed...... significant depolymerization effect on cotton cellulose. An oxalic acid/sodium oxalate buffered pH gradient had an inhibitory effect on the reduction of cellulose polymers at increased pH values. The organic iron chelator, EDTA, was found to promote depolymerization of cellulose in combination with Fenton......’s reagents, but inhibited the effect of oxalic acid in the absence of iron and hydrogen peroxide. Manganese was tested to see if metals other than iron could generate a significant impact on the degree of polymerization (DP) in cotton cellulose. Depolymerizing properties comparable to iron were seen...

  6. 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

  7. 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...

  8. 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

  9. 索拉非尼抑制人肝星状细胞胶原合成%Inhibitory effect of sorafenib on collagen synthesis in human hepatic stellate cells

    Institute of Scientific and Technical Information of China (English)

    高俊茶; 王妍; 姜慧卿

    2012-01-01

    目的:研究索拉非尼(sorafenib)对人肝星状细胞胶原合成的影响.方法:应用人肝星状细胞株LX-2进行体外研究,采用[3H]-脯氨酸掺入法测定胶原的合成,采用免疫细胞化学法检测I型胶原蛋白表达,采用real-time PCR法测定I型胶原α1 mRNA表达.结果:免疫细胞化学研究显示血小板源性生长因子(PDGF)刺激可引起LX-2细胞胶原合成增加,10.0 μmol·L-1索拉非尼作用于LX-2细胞 24 h能明显抑制I型胶原蛋白的合成.无论有无PDGF的刺激,索拉非尼均呈剂量与时间依赖性地抑制LX-2细胞胶原合成(P<0.01);在10.0 μmol·L-1浓度下,索拉非尼作用于LX-2细胞 12 h、24 h和48 h对胶原合成的抑制率为22.69%、37.52%和71.74%.索拉非尼剂量依赖性地抑制PDGF诱导的I型胶原α1 mRNA表达上调;在2.5 μmol·L-1、5.0 μmol·L-1和10.0 μmol·L-1 索拉非尼作用下,I型胶原α1 mRNA表达较PDGF刺激组分别下调58.66%、67.06%和81.64%.结论:索拉非尼在体外能抑制人肝星状细胞胶原的合成,抑制I型胶原的表达,有可能成为一种新型的治疗肝纤维化药物.%AIM:To investigate the effects of sorafenib on collagen synthesis in human hepatic stellate cells ( HSCs ). METHODS : HSC cell line LX - 2 was used in vitro in this study. [3 H ] - proline incorporation assay was performed to measure the collagen synthesis. Immunocytochemistry was applied to detect type I collagen and real -time PCR was used to determine the mRNA expression of collagen al ( I). RESULTS: Stimulation with platelet - derived growth factor ( PDGF ) induced the increase in type I collagen synthesis, while treatment with sorafenib ( 10. 0μmol/L) for 24 h markedly decreased the collagen synthesis. Sorafenib resulted in dose - dependent and time - dependent decrease in collagen synthesis in LX -2 cells in the absence or presence of PDGF by [3 H ] - proline incorporation assay. The inhibition rates were 22. 69% , 37. 52% and 71.74% , respectively

  10. 微波加热合成低取代羟丙基纤维素的工艺研究%Synthesis of Low Substituted Hydroxypropyl Cellulose Under Microwave

    Institute of Scientific and Technical Information of China (English)

    潘继成

    2014-01-01

    Hydroxypropyl cellulose is an important product of cellulose derivatives. In this paper, based on the preparation technology of cellulose, the low substituted hydroxypropyl cellulose was successfully synthesized through technical improvement, the reaction time was reduced by 1/3, and the energy consumption was also decreased under microwave heating in non-aqueous system.%羟丙基纤维素是纤维素衍生物中的一种重要产品,在已有制备基纤维素的工艺基础上,通过技术改进,实现在微波加热下在非水相体系中制备低取代羟丙基纤维素,反应时间减少了1/3,且耗能降低。

  11. Mechanics of Cellulose Synthase Complexes in Living Plant Cells

    Science.gov (United States)

    Zehfroosh, Nina; Liu, Derui; Ramos, Kieran P.; Yang, Xiaoli; Goldner, Lori S.; Baskin, Tobias I.

    The polymer cellulose is one of the major components of the world's biomass with unique and fascinating characteristics such as its high tensile strength, renewability, biodegradability, and biocompatibility. Because of these distinctive aspects, cellulose has been the subject of enormous scientific and industrial interest, yet there are still fundamental open questions about cellulose biosynthesis. Cellulose is synthesized by a complex of transmembrane proteins called ``Cellulose Synthase A'' (CESA) in the plasma membrane. Studying the dynamics and kinematics of the CESA complex will help reveal the mechanism of cellulose synthesis and permit the development and validation of models of CESA motility. To understand what drives these complexes through the cell membrane, we used total internal reflection fluorescence microscopy (TIRFM) and variable angle epi-fluorescence microscopy to track individual, fluorescently-labeled CESA complexes as they move in the hypocotyl and root of living plants. A mean square displacement analysis will be applied to distinguish ballistic, diffusional, and other forms of motion. We report on the results of these tracking experiments. This work was funded by NSF/PHY-1205989.

  12. High-yield production of extracellular type-I cellulose by the cyanobacterium Synechococcus sp. PCC 7002.

    Science.gov (United States)

    Zhao, Chi; Li, Zhongkui; Li, Tao; Zhang, Yingjiao; Bryant, Donald A; Zhao, Jindong

    2015-01-01

    Cellulose synthase, encoded by the cesA gene, is responsible for the synthesis of cellulose in nature. We show that the cell wall of the cyanobacterium Synechococcus sp. PCC 7002 naturally contains cellulose. Cellulose occurs as a possibly laminated layer between the inner and outer membrane, as well as being an important component of the extracellular glycocalyx in this cyanobacterium. Overexpression of six genes, cmc-ccp-cesAB-cesC-cesD-bgl, from Gluconacetobacter xylinus in Synechococcus sp. PCC 7002 resulted in very high-yield production of extracellular type-I cellulose. High-level cellulose production only occurred when the native cesA gene was inactivated and when cells were grown at low salinity. This system provides a method for the production of lignin-free cellulose from sunlight and CO2 for biofuel production and other biotechnological applications.

  13. Efficient delivery to human lung fibroblasts (WI-38) of pirfenidone incorporated into liposomes modified with truncated basic fibroblast growth factor and its inhibitory effect on collagen synthesis in idiopathic pulmonary fibrosis.

    Science.gov (United States)

    Togami, Kohei; Miyao, Aki; Miyakoshi, Kei; Kanehira, Yukimune; Tada, Hitoshi; Chono, Sumio

    2015-01-01

    In the present in vitro study, we assessed the delivery of pirfenidone incorporated into liposomes modified with truncated basic fibroblast growth factor (tbFGF) to lung fibroblasts and investigated the anti-fibrotic effect of the drug. The tbFGF peptide, KRTGQYKLC, was used to modify the surface of liposomes (tbFGF-liposomes). We used the thin-layer evaporation method, followed by sonication, to prepare tbFGF-liposomes containing pirfenidone. The cellular accumulation of tbFGF-liposomes was 1.7-fold greater than that of non-modified liposomes in WI-38 cells used as a model of lung fibroblasts. Confocal laser scanning microscopy showed that tbFGF-liposomes were widely localized in WI-38 cells. The inhibitory effects of pirfenidone incorporated into tbFGF-liposomes on transforming growth factor-β1 (TGF-β1)-induced collagen synthesis in WI-38 cells were evaluated by measuring the level of intracellular hydroxyproline, a major component of the protein collagen. Pirfenidone incorporated into tbFGF-liposomes at concentrations of 10, 30, and 100 µM significantly decreased the TGF-β1-induced hydroxyproline content in WI-38 cells. The anti-fibrotic effect of pirfenidone incorporated into tbFGF-liposomes was enhanced compared with that of pirfenidone solution. These results indicate that tbFGF-liposomes are a useful drug delivery system of anti-fibrotic drugs to lung fibroblasts for the treatment of idiopathic pulmonary fibrosis.

  14. Synthesis, X-ray crystallography, spectroscopic (FT-IR, 1H &13C NMR and UV), computational (DFT/B3LYP) and enzymes inhibitory studies of 7-hydroximinocholest-5-en-3-ol acetate

    Science.gov (United States)

    Ahmad, Faheem; Parveen, Mehtab; Alam, Mahboob; Azaz, Shaista; Malla, Ali Mohammed; Alam, Mohammad Jane; Lee, Dong-Ung; Ahmad, Shabbir

    2016-07-01

    The present study reports the synthesis of 7-Hydroximinocholest-5-en-3-ol acetate (syn. 3β-acetoxycholest-5-en-7-one oxime; in general, steroidal oxime). The identity of steroidal molecule was confirmed by NMR, FT-IR, MS, CHN microanalysis and X-ray crystallography. DFT calculations on the titled molecule have been performed. The molecular structure and spectra interpreted by Gaussian hybrid computational analysis theory (B3LYP) are found to be in good correlation with the experimental data obtained from the various spectrophotometric techniques. The vibrational bands appearing in the FTIR are assigned with great accuracy using harmonic frequencies along with intensities and animated modes. Molecular properties like HOMO-LUMO analysis, chemical reactivity descriptors, MEP mapping, dipole moment and natural atomic charges have been presented at the same level of theory. Moreover, the Hirshfeld analysis was carried out to ascertain the secondary interactions and associated 2D fingerprint plots. The percentages of various interactions are pictorialized by fingerprint plots of Hirshfeld surface. Steroidal oxime exhibited promising inhibitory activity against acetylcholinesterase (AChE) as compared to the reference drug, tacrine. Molecular docking was performed to introduce steroidal molecules into the X-ray crystal structures of acetylcholinesterase at the active site to find out the probable binding mode. The results of molecular docking admitted that steroidal oxime may exhibit enzyme inhibitor activity.

  15. Hydrolysis of ionic cellulose to glucose.

    Science.gov (United States)

    Vo, Huyen Thanh; Widyaya, Vania Tanda; Jae, Jungho; Kim, Hoon Sik; Lee, Hyunjoo

    2014-09-01

    Hydrolysis of ionic cellulose (IC), 1,3-dimethylimidazolium cellulose phosphite, which could be synthesized from cellulose and dimethylimidazolium methylphosphite ([Dmim][(OCH3)(H)PO2]) ionic liquid, was conducted for the synthesis of glucose. The reaction without catalysts at 150°C for 12h produced glucose with 14.6% yield. To increase the hydrolysis yield, various acid catalysts were used, in which the sulfonated active carbon (AC-SO3H) performed the best catalytic activity in the IC hydrolysis. In the presence of AC-SO3H, the yields of glucose reached 42.4% and 53.9% at the reaction condition of 150°C for 12h and 180°C for 1.5h, respectively; however the yield decreased with longer reaction time due to the degradation of glucose. Consecutive catalyst reuse experiments on the IC hydrolysis demonstrated the catalytic activity of AC-SO3H persisted at least through four successive uses. Copyright © 2014 Elsevier Ltd. All rights reserved.

  16. Synthesis, Docking and Acetylcholinesterase Inhibitory Assessment of 2-(2-(4-Benzylpiperazin-1-YlEthylIsoindoline-1,3-Dione Derivatives with Potential Anti-Alzheimer Effects

    Directory of Open Access Journals (Sweden)

    Ahmad Mohammadi-Farani

    2013-06-01

    Full Text Available Background:Alzheimer’s disease (AD as neurodegenerative disorder, is the most common form of dementia accounting for about 50-60% of the overall cases of dementia among persons over 65 years of age. Low acetylcholine (ACh concentration in hippocampus and cortex areas of the brain is one of the main reasons for this disease. In recent years, acetylcholinesterase (AChE inhibitors like donepezil with prevention of acetylcholine hydrolysis can enhance the duration of action of acetylcholine in synaptic cleft and improve the dementia associated with Alzheimer’s disease.Results:Design, synthesis and assessment of anticholinesterase activity of 2-(2-(4-Benzylpiperazin-1-ylethylisoindoline-1,3-dione derivatives showed prepared compounds can function as potential acetylcholinesterase inhibitor. Among 12 synthesized derivatives, compound 4a with ortho chlorine moiety as electron withdrawing group exhibited the highest potency in these series (IC50 = 0.91 ± 0.045 μM compared to donepezil (IC50 = 0.14 ± 0.03 μM. The results of the enzyme inhibition test (Ellman test showed that electron withdrawing groups like Cl, F and NO2 can render the best effect at position ortho and para of the phenyl ring. But compound 4g with methoxy group at position 3(meta afforded a favorable potency (IC50 = 5.5 ± 0.7 μM. Furthermore, docking study confirmed a same binding mode like donepezil for compound 4a.Conclusions:Synthesized compounds 4a-4l could be proposed as potential anticholinesterase agents.

  17. 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.

  18. 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.

  19. Maleic acid treatment of bioabated corn stover liquors improves cellulose conversion to ethanol

    Science.gov (United States)

    Elimination of inhibitory compounds released during pretreatment of lignocellulose is critical for efficient cellulose conversion and ethanol fermentation. This study examined the effect of bioabated liquor from pretreated corn stover on enzyme hydrolysis of Solka Floc or pretreated corn stover soli...

  20. Biology-oriented drug synthesis (BIODS): In vitro β-glucuronidase inhibitory and in silico studies on 2-(2-methyl-5-nitro-1H-imidazol-1-yl)ethyl aryl carboxylate derivatives.

    Science.gov (United States)

    Salar, Uzma; Khan, Khalid Mohammed; Taha, Muhammad; Ismail, Nor Hadiani; Ali, Basharat; Qurat-Ul-Ain; Perveen, Shahnaz; Ghufran, Mehreen; Wadood, Abdul

    2017-01-05

    Current study is based on the biology-oriented drug synthesis (BIODS) of 2-(2-methyl-5-nitro-1H-imidazol-1-yl)ethyl aryl carboxylate derivatives 1-26, by treating metronidazole with different aryl and hetero-aryl carboxylic acids in the presence of 1,1'-carbonyl diimidazole (CDI) as a coupling agent. Structures of all synthetic derivatives were confirmed with the help of various spectroscopic techniques such as EI-MS, (1)H -NMR and (13)C NMR. CHN elemental analyses were also found in agreement with the calculated values. Synthetic derivatives were evaluated to check their β-glucuronidase inhibitory activity which revealed that except few derivatives, all demonstrated good inhibition in the range of IC50 = 1.20 ± 0.01-60.30 ± 1.40 μM as compared to the standard d-saccharic acid 1,4-lactone (IC50 = 48.38 ± 1.05 μM). Compounds 1, 3, 4, 6, 9-19, and 21-24 were found to be potent analogs and showed superior activity than standard. Limited structure-activity relationship is suggested that the molecules having electron withdrawing groups like NO2, F, Cl, and Br, were displayed better activity than the compounds with electron donating groups such as Me, OMe and BuO. To verify these interpretations, in silico study was also performed, a good correlation was observed between bioactivities and docking studies. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  1. Hydroboration-oxidation: A chemoselective route to cellulose ω-hydroxyalkanoate esters.

    Science.gov (United States)

    Meng, Xiangtao; York, Emily A; Liu, Shu; Edgar, Kevin J

    2015-11-20

    We describe the first synthesis of hydroxy-functionalized polysaccharide esters via chemoselective olefin hydroboration-oxidation in the presence of ester groups. Cellulose esters with terminally olefinic side chains were first synthesized by esterification of commercially available cellulose esters (e.g., cellulose acetate) with undec-10-enoyl chloride or pent-4-enoyl chloride. Subsequent two-step, one-pot hydroboration-oxidation reactions of the cellulose esters were performed, using 9-borabicyclo[3.3.1]nonane as hydroboration agent, followed by oxidizing the intermediate borane to a hydroxyl group using mildly alkaline H2O2. Sodium acetate was used as a weak base to catalyze the oxidation, thereby minimizing undesired ester hydrolysis. Characterization methods including FTIR, (1)H, and (13)C NMR proved the selectivity of the hydroboration-oxidation pathway, providing a family of novel cellulose ω-hydroxyalkanoyl esters that were previously difficult to access. Copyright © 2015 Elsevier Ltd. All rights reserved.

  2. A versatile pathway to end-functionalized cellulose ethers for click chemistry applications.

    Science.gov (United States)

    Kamitakahara, Hiroshi; Suhara, Ryo; Yamagami, Mao; Kawano, Haruko; Okanishi, Ryoko; Asahi, Tomoyuki; Takano, Toshiyuki

    2016-10-20

    This paper describes a versatile pathway to heterobifunctional/telechelic cellulose ethers, such as tri-O-methyl cellulosyl azide and propargyl tri-O-methyl celluloside, having one free C-4 hydroxyl group attached to the glucosyl residue at the non-reducing end for the use in Huisgen 1,3-dipolar cycloaddition and copper(I)-catalyzed azide-alkyne cycloaddition (CuAAC). The one-step end-functionalization of cellulose ethers for molecular rod synthesis involves the introduction of two reactive groups at both ends of the cellulose molecule, and can afford linear triblock copolymers via CuAAC and further reactions. We were able to tailor the degree of polymerization of end-functionalized cellulose ethers with controlled amounts of a Lewis acid, namely SnCl4. Chemical structures of the above cellulose ethers and the reaction conditions for controlling molecular length are discussed.

  3. Acetoacetylation of Hydroxyethyl Cellulose

    Institute of Scientific and Technical Information of China (English)

    陈晓锋; 高彦芳; 杜奕; 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.

  4. 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.

  5. 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.

  6. Debranching of soluble wheat arabinoxylan dramatically enhances recalcitrant binding to cellulose

    DEFF Research Database (Denmark)

    Selig, Michael J.; Thygesen, Lisbeth G.; Felby, Claus;

    2015-01-01

    The presence of xylan is a detriment to the enzymatic saccharification of cellulose in lignocelluloses. The inhibition of the processive cellobiohydrolase Cel7A by soluble wheat arabinoxylan is shown here to increase by 50 % following enzymatic treatment with a commercially-purified α-l-arabinofu......The presence of xylan is a detriment to the enzymatic saccharification of cellulose in lignocelluloses. The inhibition of the processive cellobiohydrolase Cel7A by soluble wheat arabinoxylan is shown here to increase by 50 % following enzymatic treatment with a commercially-purified α...... considerably increased the rate and rigidity of arabinoxylan mass association with cellulose. These data also suggest significant xylan–xylan adlayer formation occurs following initial binding of debranched arabinoxylan. From this, we speculate the inhibitory effects of xylan to cellulases may result from...... reduced enzymatic access via the dense association of xylan with cellulose....

  7. Eco-friendly hybrid pigments made of cellulose and iron oxides.

    Science.gov (United States)

    Neves, M C; Pascoal Neto, C; Trindade, T

    2012-08-01

    The controlled hydrolysis of FeC2O4 in the presence of vegetable cellulose fibres was investigated to produce a pallet of cellulose/iron oxide hybrid colored materials. Distinct iron oxide phases have been deposited at the cellulose fibres surfaces by varying the relative amount of FeC2O4 and NaOH, here used as starting materials, by performing the synthesis in hydrothermal conditions. This is a new chemical strategy for the production of a number of hybrid materials whose coloristic properties have been evaluated aiming their potential use as novel pigments for polymer based products.

  8. 纳米银在细菌纤维素凝胶膜中的原位合成及性能表征%Synthesis, Structural Characteristics and Properties of Silver Nanoparticles in situ Bacterial Cellulose Gelatinous Membrane

    Institute of Scientific and Technical Information of China (English)

    吴健; 郑裕东; 高爽; 郭佳; 崔秋艳; 丁寻; 陈晓华

    2013-01-01

    Silver nanoparticles/bacterial cellulose ( n-Ag/BC) composite membranes were prepared and characterized. Silver nanoparticles were synthesized in situ through the reaction of Tollens' reagent with aldehydes , under ambient conditions in nanoporous bacterial cellulose membrances as nanoreactors. Sliver nanop-article was readily obtained and grew into the BC network by the precipitation of above reaction products. BC films were prepared and loaded with ca. 0. 14 mg/cm2 to ca. 0. 42 mg/cm2 of silver nanoparticles. XRD patterns indicated the existence of Ag0 nanoparticles in the BC, and the diameter of the silver nanoparticles is ca. 31. 8 nm. Scanning electron microscopy (SEM) images showed that the sliver nanoparticles (size range dozens nm) well dispersed in the network of BC. The sliver nanoparticle-impregnated BC membranes exhibited high hydrophilic ability and strong antimicrobial activity. Bacterial killing efficiencies of the silver loaded films were investigated against staphylococcus aureus. It was determined that as little as ca. 0. 14 mg/cm2 of silver in the BC films caused a reduction of 99% bacteria in suspensions incubated in contact with the films. Significantly, the n-Ag/BC antimicrobial membranes were good biocompatibility, and allowed the attachment and growth of the epidermal cells. The result shows an easy method to synthesis silver nanoparticles into BC membranes. The n-Ag/BC has stability, antimicrobial activity and biological properties. The preparative procedure is facile, and provides a simple route to manufacturing of useful antimicrobial membranes, which would be a good alternative for antimicrobial wound dressing.%在细菌纤维素纳米纤维网络结构中采用吐伦试剂与含醛基化合物原位反应生成纳米银颗粒,制备了纳米银/细菌纤维素(n-Ag/BC)复合凝胶膜,研究了不同反应条件对复合材料的银含量、化学结构和晶体结构的影响以及n-Ag/BC的微观结构和纳米银在纤维素网络中

  9. 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...

  10. Brassinosteroids can regulate cellulose biosynthesis by controlling the expression of CESA genes in Arabidopsis.

    Science.gov (United States)

    Xie, Liqiong; Yang, Cangjing; Wang, Xuelu

    2011-08-01

    The phytohormones, brassinosteroids (BRs), play important roles in regulating cell elongation and cell size, and BR-related mutants in Arabidopsis display significant dwarf phenotypes. Cellulose is a biopolymer which has a major contribution to cell wall formation during cell expansion and elongation. However, whether BRs regulate cellulose synthesis, and if so, what the underlying mechanism of cell elongation induced by BRs is, is unknown. The content of cellulose and the expression levels of the cellulose synthase genes (CESAs) was measured in BR-related mutants and their wild-type counterpart. The chromatin immunoprecipitation (CHIP) experiments and genetic analysis were used to demonstrate that BRs regulate CESA genes. It was found here that the BR-deficient or BR-perceptional mutants contain less cellulose than the wild type. The expression of CESA genes, especially those related to primary cell wall synthesis, was reduced in det2-1 and bri1-301, and was only inducible by BRs in the BR-deficient mutant det2-1. CHIP experiments show that the BR-activated transcription factor BES1 can associate with upstream elements of most CESA genes particularly those related with the primary cell wall. Furthermore, over-expression of the BR receptor BRI1 in CESA1, 3, and 6 mutants can only partially rescue the dwarf phenotypes. Our findings provide potential insights into the mechanism that BRs regulate cellulose synthesis to accomplish the cell elongation process in plant development.

  11. 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...

  12. 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...

  13. 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, ...

  14. Effect of Gluconacetobacter xylinus cultivation conditions on the selected properties of bacterial cellulose

    Directory of Open Access Journals (Sweden)

    Fijałkowski Karol

    2016-12-01

    Full Text Available The aim of the study was to analyze the changes in the parameters of bacterial cultures and bacterial cellulose (BC synthesized by four reference strains of Gluconacetobacter xylinus during 31-day cultivation in stationary conditions. The study showed that the most visible changes in the analyzed parameters of BC, regardless of the bacterial strain used for their synthesis, were observed in the first 10–14 days of the experiment. It was also revealed, that among parameters showing dependence associated with the particular bacterial strain were the rate and period of BC synthesis, the growth rate of bacteria anchored to the cellulose fibrils, the capacity to absorb water and the water release rate. The results presented in this work may be useful in the selection of optimum culturing conditions and period from the point of view of good efficiency of the cellulose synthesis process.

  15. 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.

  16. Synthesis of Polymer Nanocomposites Based on [Methyl Cellulose](1−x):(CuS)x (0.02 M ≤ x ≤ 0.08 M) with Desired Optical Band Gaps

    OpenAIRE

    Aziz, Shujahadeen B.; Rasheed, Mariwan A.; Hameed M. Ahmed

    2017-01-01

    In this paper, the sample preparation of polymer nanocomposites based on methyl cellulose (MC) with small optical bandgaps has been discussed. Copper monosulfide (CuS) nanoparticles have been synthesized from the sodium sulphide (Na2S) and copper chloride (CuCl2) salts. Distinguishable localized surface resonance plasmon (LSRP) absorption peaks for CuS nanoparticles within the 680–1090 nm scanned wavelength range were observed for the samples. An absorption edge (Ed) was found to be widely sh...

  17. Amphiphilic Cellulose Ethers Designed for Amorphous Solid Dispersion via Olefin Cross-Metathesis.

    Science.gov (United States)

    Dong, Yifan; Mosquera-Giraldo, Laura I; Taylor, Lynne S; Edgar, Kevin J

    2016-02-01

    The design of cellulose ether-based amphiphiles has been difficult and limited because of the harsh conditions typically required for appending ether moieties to cellulose. Olefin cross-metathesis recently has been shown to be a valuable approach for appending a variety of functional groups to cellulose ethers and esters, provided that an olefin handle for metathesis can be attached. This synthetic pathway gives access to these functional derivatives under very mild conditions and at high efficiency. Modification of ethyl cellulose by metathesis to prepare useful derivatives, for example, for solubility and bioavailability enhancement of drugs by amorphous solid dispersion (ASD), has been limited by the low DS(OH) of commercial ethyl cellulose derivatives. This is problematic because ethyl cellulose is otherwise a very attractive substrate for synthesis of amphiphilic derivatives by olefin metathesis. Herein we explore two methods for opening up this design space for ether-based amphiphiles, for example, permitting synthesis of more hydrophilic derivatives. One approach is to start with the more hydrophilic commercial methyl cellulose, which contains much higher DS(OH) and therefore is better suited for introduction of high DS of olefin metathesis "handles". In another approach, we explored a homogeneous one-pot synthesis methodology from cellulose, where controlled DS of ethyl groups was introduced at the same time as the ω-unsaturated alkyl groups, thereby permitting complete control of DS(OH), DS(Et), and ultimately DS of the functional group added by metathesis. We describe the functionalized derivatives available by these successful approaches. In addition, we explore new methods for reduction of the unsaturation in initial metathesis products to provide robust methods for enhancing product stability against further radical-catalyzed reactions. We demonstrate initial evidence that the products show strong promise as amphiphilic matrix polymers for amorphous

  18. 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.

  19. Structure of the Cellulose Synthase Complex of Gluconacetobacter hansenii at 23.4 A Resolution.

    Directory of Open Access Journals (Sweden)

    Juan Du

    Full Text Available Bacterial crystalline cellulose is used in biomedical and industrial applications, but the molecular mechanisms of synthesis are unclear. Unlike most bacteria, which make non-crystalline cellulose, Gluconacetobacter hansenii extrudes profuse amounts of crystalline cellulose. Its cellulose synthase (AcsA exists as a complex with accessory protein AcsB, forming a 'terminal complex' (TC that has been visualized by freeze-fracture TEM at the base of ribbons of crystalline cellulose. The catalytic AcsAB complex is embedded in the cytoplasmic membrane. The C-terminal portion of AcsC is predicted to form a translocation channel in the outer membrane, with the rest of AcsC possibly interacting with AcsD in the periplasm. It is thus believed that synthesis from an organized array of TCs coordinated with extrusion by AcsC and AcsD enable this bacterium to make crystalline cellulose. The only structural data that exist for this system are the above mentioned freeze-fracture TEM images, fluorescence microscopy images revealing that TCs align in a row, a crystal structure of AcsD bound to cellopentaose, and a crystal structure of PilZ domain of AcsA. Here we advance our understanding of the structural basis for crystalline cellulose production by bacterial cellulose synthase by determining a negative stain structure resolved to 23.4 Å for highly purified AcsAB complex that catalyzed incorporation of UDP-glucose into β-1,4-glucan chains, and responded to the presence of allosteric activator cyclic diguanylate. Although the AcsAB complex was functional in vitro, the synthesized cellulose was not visible in TEM. The negative stain structure revealed that AcsAB is very similar to that of the BcsAB synthase of Rhodobacter sphaeroides, a non-crystalline cellulose producing bacterium. The results indicate that the crystalline cellulose producing and non-crystalline cellulose producing bacteria share conserved catalytic and membrane translocation components, and

  20. Structure of the Cellulose Synthase Complex of Gluconacetobacter hansenii at 23.4 Å Resolution

    Science.gov (United States)

    Du, Juan; Vepachedu, Venkata; Cho, Sung Hyun; Kumar, Manish; Nixon, B. Tracy

    2016-01-01

    Bacterial crystalline cellulose is used in biomedical and industrial applications, but the molecular mechanisms of synthesis are unclear. Unlike most bacteria, which make non-crystalline cellulose, Gluconacetobacter hansenii extrudes profuse amounts of crystalline cellulose. Its cellulose synthase (AcsA) exists as a complex with accessory protein AcsB, forming a 'terminal complex' (TC) that has been visualized by freeze-fracture TEM at the base of ribbons of crystalline cellulose. The catalytic AcsAB complex is embedded in the cytoplasmic membrane. The C-terminal portion of AcsC is predicted to form a translocation channel in the outer membrane, with the rest of AcsC possibly interacting with AcsD in the periplasm. It is thus believed that synthesis from an organized array of TCs coordinated with extrusion by AcsC and AcsD enable this bacterium to make crystalline cellulose. The only structural data that exist for this system are the above mentioned freeze-fracture TEM images, fluorescence microscopy images revealing that TCs align in a row, a crystal structure of AcsD bound to cellopentaose, and a crystal structure of PilZ domain of AcsA. Here we advance our understanding of the structural basis for crystalline cellulose production by bacterial cellulose synthase by determining a negative stain structure resolved to 23.4 Å for highly purified AcsAB complex that catalyzed incorporation of UDP-glucose into β-1,4-glucan chains, and responded to the presence of allosteric activator cyclic diguanylate. Although the AcsAB complex was functional in vitro, the synthesized cellulose was not visible in TEM. The negative stain structure revealed that AcsAB is very similar to that of the BcsAB synthase of Rhodobacter sphaeroides, a non-crystalline cellulose producing bacterium. The results indicate that the crystalline cellulose producing and non-crystalline cellulose producing bacteria share conserved catalytic and membrane translocation components, and support the

  1. Synthesis, characterization and cholinesterase enzymes inhibitory activity of 1-[3-methyl-5-(2,6,6-trimethyl-cyclohex-1-enyl)-4,5-dihydro-pyrazol-1-yl]-ethanone

    Science.gov (United States)

    Mehdi, Sayed Hasan; Ghalib, Raza Murad; Hashim, Rokiah; da Silva, M. Fátima C. Guedes; Sulaiman, Othman; Murugaiyah, Vikneswaran; Marimuthu, Mani Maran; Naqvi, Mehnaz

    2013-10-01

    The crystal structure of the title compound, 1-[3-methyl-5-(2,6,6-trimethyl-cyclohex-1-enyl)-4,5-dihydro-pyrazol-1-yl]-ethanone has been determined by single crystal X-ray diffraction. It crystallizes in the orthorhombic space group P212121. The FTIR as well as the 1H and 13C NMR spectra of the compound were also recorded and briefly discussed. Compound 1 demonstrated good inhibitory activity against butyrylcholinesterase (BChE; IC50 = 46.42 μM) comparable to physostigmine. However it showed moderate inhibitory activity against acetylcholinesterase (AChE; IC50 = 157.31 μM). It showed moderate inhibitory activity against acetylcholinesterase and selective inhibitory activity towards butyrylcholinesterase enzyme.

  2. 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)

  3. 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, cross-checking of results from different analysis techniques is fundamental for the development of reliable cellulose nanocrystal modification techniques.

  4. Role of Rhizobium endoglucanase CelC2 in cellulose biosynthesis and biofilm formation on plant roots and abiotic surfaces

    Directory of Open Access Journals (Sweden)

    Robledo M

    2012-09-01

    Full Text Available Abstract Background The synthesis of cellulose is among the most important but poorly understood biochemical processes, especially in bacteria, due to its complexity and high degree of regulation. In this study, we analyzed both the production of cellulose by all known members of the Rhizobiaceae and the diversity of Rhizobium celABC operon predicted to be involved in cellulose biosynthesis. We also investigated the involvement in cellulose production and biofilm formation of celC gene encoding an endoglucanase (CelC2 that is required for canonical symbiotic root hair infection by Rhizobium leguminosarum bv. trifolii. Results ANU843 celC mutants lacking (ANU843ΔC2 or overproducing cellulase (ANU843C2+ produced greatly increased or reduced amounts of external cellulose micro fibrils, respectively. Calcofluor-stained cellulose micro fibrils were considerably longer when formed by ANU843ΔC2 bacteria rather than by the wild-type strain, in correlation with a significant increase in their flocculation in batch culture. In contrast, neither calcofluor-stained extracellular micro fibrils nor flocculation was detectable in ANU843C2+ cells. To clarify the role of cellulose synthesis in Rhizobium cell aggregation and attachment, we analyzed the ability of these mutants to produce biofilms on different surfaces. Alteration of wild-type CelC2 levels resulted in a reduced ability of bacteria to form biofilms both in abiotic surfaces and in planta. Conclusions Our results support a key role of the CelC2 cellulase in cellulose biosynthesis by modulating the length of the cellulose fibrils that mediate firm adhesion among Rhizobium bacteria leading to biofilm formation. Rhizobium cellulose is an essential component of the biofilm polysaccharidic matrix architecture and either an excess or a defect of this “building material” seem to collapse the biofilm structure. These results position cellulose hydrolytic enzymes as excellent anti-biofilm candidates.

  5. 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).

  6. KORRIGAN1 interacts specifically with integral components of the cellulose synthase machinery.

    Directory of Open Access Journals (Sweden)

    Nasim Mansoori

    Full Text Available Cellulose is synthesized by the so called rosette protein complex and the catalytic subunits of this complex are the cellulose synthases (CESAs. It is thought that the rosette complexes in the primary and secondary cell walls each contains at least three different non-redundant cellulose synthases. In addition to the CESA proteins, cellulose biosynthesis almost certainly requires the action of other proteins, although few have been identified and little is known about the biochemical role of those that have been identified. One of these proteins is KORRIGAN (KOR1. Mutant analysis of this protein in Arabidopsis thaliana showed altered cellulose content in both the primary and secondary cell wall. KOR1 is thought to be required for cellulose synthesis acting as a cellulase at the plasma membrane-cell wall interface. KOR1 has recently been shown to interact with the primary cellulose synthase rosette complex however direct interaction with that of the secondary cell wall has never been demonstrated. Using various methods, both in vitro and in planta, it was shown that KOR1 interacts specifically with only two of the secondary CESA proteins. The KOR1 protein domain(s involved in the interaction with the CESA proteins were also identified by analyzing the interaction of truncated forms of KOR1 with CESA proteins. The KOR1 transmembrane domain has shown to be required for the interaction between KOR1 and the different CESAs, as well as for higher oligomer formation of KOR1.

  7. Design and synthesis of novel 2,4-diaryl-5H-indeno[1,2-b]pyridine derivatives, and their evaluation of topoisomerase inhibitory activity and cytotoxicity.

    Science.gov (United States)

    Kadayat, Tara Man; Park, Chanmi; Jun, Kyu-Yeon; Magar, Til Bahadur Thapa; Bist, Ganesh; Yoo, Han Young; Kwon, Youngjoo; Lee, Eung-Seok

    2015-01-01

    For the development of potential anticancer agents, we designed and synthesized 30 new 2,4-diaryl-5H-indeno[1,2-b]pyridine derivatives containing aryl moiety such as furyl, thienyl, pyridyl, and phenyl at 2- and 4-position of 5H-indeno[1,2-b]pyridine. They were evaluated for topoisomerase I and II inhibitory activity, and cytotoxicity against several human cancer cell lines. Among prepared 30 compounds, 7, 8, 9, 10, 12, 14, 16, 19, 20, 22, and 23 with 2- or 3-furyl and/or 2- or 3-thienyl either at 2- or 4-position of central pyridine showed the significant or moderate topoisomerase II inhibitory activity. Compounds 7, 8, 11, 12, 13, and 22 with 2-furyl, 2-thienyl or 3-thienyl at 2-position of central pyridine showed the significant or moderate topoisomerase I inhibitory activity. Especially, compound 12 with strong topoisomerase II inhibitory activity at 100 μM and 20 μM, and moderate topoisomerase I inhibitory activity displayed strong cytotoxicity against several human cancer cell lines.

  8. Ionic Liquids — Promising but Challenging Solvents for Homogeneous Derivatization of Cellulose

    Directory of Open Access Journals (Sweden)

    Pedro Fardim

    2012-06-01

    Full Text Available In the past decade, ionic liquids (ILs have received enormous interest as solvents for cellulose. They have been studied intensively for fractionation and biorefining of lignocellulosic biomass, for dissolution of the polysaccharide, for preparation of cellulosic fibers, and in particular as reaction media for the homogeneous preparation of highly engineered polysaccharide derivatives. ILs show great potential for application on a commercial scale regarding recyclability, high dissolution power, and their broad structural diversity. However, a critical analysis reveals that these promising features are combined with serious drawbacks that need to be addressed in order to utilize ILs for the efficient synthesis of cellulose derivatives. This review presents a comprehensive overview about chemical modification of cellulose in ILs. Difficulties encountered thereby are discussed critically and current as well as future developments in this field of polysaccharide research are outlined.

  9. He-Ne激光重复照射抑制培养增生性瘢痕成纤维细胞胶原合成的实验研究%Inhibitory effects of He Ne laser repeated irradiation on collagen synthesis in hypertrophic scar derived fibroblasts in culture

    Institute of Scientific and Technical Information of China (English)

    杨宏珍; 杨西川

    2002-01-01

    Objective To explore the inhibitory effects of He Ne laser repeated irradiation on the collagen synthesis of cultured scar fibroblasts. Method Cultured fibroblasts derived from hypertrophic scars(HS) were irradiated with He Ne laser for 30 minutes at various power densities(10,50,100 and 150 mW/cm2),once a day for 3 consecutive days.In 24 hours after repeated irradiation collagen production and type I procollagen mRNA level of fibroblasts were measured with the incorporation of 3H proline and blot hybridization techniques espectively.Results Collagen synthesis and type I procollagen mRNA level remained unchanged when the laser was irradiated at the power density of 10 mW/cm2 or 50 mW/cm2.Compared with control,collagen synthesis and type I procollagne mRNA level were significantly decreases at the power density of 100 mW/cm2 or 150mW/cm2(P< 0.05).Type I procollagen mRNA level at the power densityof 150 mW/cm2 was lower than that at the 100 mW/cm2 (P< 0.05).Conclusion Repeated He Ne laser irradiation at the power density of 100 mW/cm2 or 150 mW/cm2 can suppress collagen synthesis of cultured fibroblasts in HS.The cause of suppression may be associated with down regulation of type I procollagen mRNA expression.

  10. AcsA-AcsB: The core of the cellulose synthase complex from Gluconacetobacter hansenii ATCC23769.

    Science.gov (United States)

    McManus, John B; Deng, Ying; Nagachar, Nivedita; Kao, Teh-hui; Tien, Ming

    2016-01-01

    The gram-negative bacterium, Gluconacetobacter hansenii, produces cellulose of exceptionally high crystallinity in comparison to the cellulose of higher plants. This bacterial cellulose is synthesized and extruded into the extracellular medium by the cellulose synthase complex (CSC). The catalytic component of this complex is encoded by the gene AcsAB. However, several other genes are known to encode proteins critical to cellulose synthesis and are likely components of the bacterial CSC. We have purified an active heterodimer AcsA-AcsB from G. hansenii ATCC23769 to homogeneity by two different methods. With the purified protein, we have determined how it is post-translationally processed, forming the active heterodimer AcsA-AcsB. Additionally, we have performed steady-state kinetic studies on the AcsA-AcsB complex. Finally through mutagenesis studies, we have explored the roles of the postulated CSC proteins AcsC, AcsD, and CcpAx.

  11. Cationic quaternization of cellulose with methacryloyloxy ethyl trimethyl ammonium chloride via ATRP method

    Energy Technology Data Exchange (ETDEWEB)

    Supeno [Cenderawasih University, Jayapura, Papua, Indonesia and School of Chemical Sciences and Food Technology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor (Malaysia); Daik, Rusli, E-mail: rusli@ukm.edu.my [School of Chemical Sciences and Food Technology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor (Malaysia); El-Sheikh, Said M. [Nano-Structured Materials Division, Advanced Materials Department, Central Metallurgical Research and Development Institute, Cairo (Egypt)

    2014-09-03

    The synthesis of a cationic cellulose copolymer from cellulose macro-initiator (MCC-BiB) and quaternary compound monomer (METMA) via atom transfer radical polymerization (ATRP) was studied. By using dimethylformamide (DMF), the optimum condition for successful synthesis was at the mole ratio of MCC-BIB:Catalyst:METMA = 1:1:26. The highest copolymer recovery was 93.2 % for 6 h and at 40°C. The copolymer was insoluble in weak polar solvents such as THF and DMF but soluble in methanol and water. The chemistry of cellulose copolymer was confirmed by the FTIR and TGA in which the METMA monomer was used as a reference. The absence of CC bond in the CiB-g-METMA spectrum indicated that graft copolymerization occurred.

  12. 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 urea-formaldehyde 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.

  13. Cellulose nanocrystals the next big nano-thing?

    Science.gov (United States)

    Postek, Michael T.; Vladar, Andras; Dagata, John; Farkas, Natalia; Ming, Bin; Sabo, Ronald; Wegner, Theodore H.; Beecher, James

    2008-08-01

    Biomass surrounds us from the smallest alga to the largest redwood tree. Even the largest trees owe their strength to a newly-appreciated class of nanomaterials known as cellulose nanocrystals (CNC). Cellulose, the world's most abundant natural, renewable, biodegradable polymer, occurs as whisker like microfibrils that are biosynthesized and deposited in plant material in a continuous fashion. Therefore, the basic raw materials for a future of new nanomaterials breakthroughs already abound in the environment and are available to be utilized in an array of future materials once the manufacturing processes and nanometrology are fully developed. This presentation will discuss some of the instrumentation, metrology and standards issues associated with nanomanufacturing of cellulose nanocrystals. The use of lignocellulosic fibers derived from sustainable, annually renewable resources as a reinforcing phase in polymeric matrix composites provides positive environmental benefits with respect to ultimate disposability and raw material use. Today we lack the essential metrology infrastructure that would enable the manufacture of nanotechnology-based products based on CNCs (or other new nanomaterial) to significantly impact the U.S. economy. The basic processes common to manufacturing - qualification of raw materials, continuous synthesis methods, process monitoring and control, in-line and off-line characterization of product for quality control purposes, validation by standard reference materials - are not generally in place for nanotechnology based products, and thus are barriers to innovation. One advantage presented by the study of CNCs is that, unlike other nanomaterials, at least, cellulose nanocrystal manufacturing is already a sustainable and viable bulk process. Literally tons of cellulose nanocrystals can be generated each day, producing other viable byproducts such as glucose (for alternative fuel) and gypsum (for buildings).There is an immediate need for the

  14. 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...

  15. Inhibitory mechanisms of glabridin on tyrosinase

    Science.gov (United States)

    Chen, Jianmin; Yu, Xiaojing; Huang, Yufeng

    2016-11-01

    Tyrosinase is an oxidase that is the rate-limiting enzyme for controlling the production of melanin in the human body. Overproduction of melanin could lead to a variety of skin disorders. Glabridin, an isoflavan, isolated from the root of Glycyrrhiza glabra Linn, has exhibited several pharmacological activities, including excellent inhibitory effects on tyrosinase. In this paper, the inhibitory kinetics of glabridin on tyrosinase and their binding mechanisms were determined using spectroscopic, zebrafish model and molecular docking techniques. The results indicate that glabridin reversibly inhibits tyrosinase in a noncompetitive manner through a multiphase kinetic process with the IC50 of 0.43 μmol/L. It has been shown that glabridin had a strong ability to quench the intrinsic fluorescence of tyrosinase mainly through a static quenching procedure, suggesting a stable glabridin-tyrosinase complex may be generated. The results of molecular docking suggest that glabridin did not directly bind to the active site of tyrosinase. Moreover, according to the results of zebrafish model system, glabridin shows no effects on melanin synthesis in zebrafish but presents toxicity to zebrafish embryo. The possible inhibitory mechanisms, which will help to design and search for tyrosinase inhibitors especially for glabridin analogues, were proposed.

  16. Visible light activated TiO2/microcrystalline cellulose nanocatalyst to destroy organic contaminants in water.

    Science.gov (United States)

    Hybrid TiO2/microcrystalline cellulose (MC) nanophotocatalyst was prepared in situ by a facile and simple synthesis utilizing benign precursors such as MC and TiCl4. The as-prepared nanocomposite was characterized by XRD, XPS, BET surface area analyzer, UV–vis DRS and TGA. Surfac...

  17. Visible light activated TiO2/microcrystalline cellulose nanocatalyst to destroy organic contaminants in water.

    Science.gov (United States)

    Hybrid TiO2/microcrystalline cellulose (MC) nanophotocatalyst was prepared in situ by a facile and simple synthesis utilizing benign precursors such as MC and TiCl4. The as-prepared nanocomposite was characterized by XRD, XPS, BET surface area analyzer, UV–vis DRS and TGA. Surfac...

  18. 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...

  19. 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

  20. 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

  1. 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

  2. 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.

  3. 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...

  4. 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...

  5. 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...

  6. Study on the Synthesis of Hydrophobically Modified Hydroxyethyl Cellulose in Ionic Liquids%离子液体中疏水改性羟乙基纤维素的合成

    Institute of Scientific and Technical Information of China (English)

    张恒; 刘丽丽; 赵娜娜; 张岩冲

    2012-01-01

    Hydrophobically modified hydroxyethyl cellulose (HMHEC) was prepared by macromolecule reaction.Hydroxyethyl cellulose was modified by grafting the hydrophobic monomer bromododecane (BD) on the hydroxyethyl cellulose (HEC).The influences of the type of ionic liquid,the reaction temperature,the concentration of hydroxyethyl and the dosage of BD on the performance of HMHEC were studied.The optimum conditions were that the concentration of HEC was 3%,the dissolving time was 1 h,the dissolving temperature was 100℃,the reaction time was 2 h,the reaction temperature was 80℃ and the dosage of BD was 2 mL.And the performance of the HMHEC that synthetized in the 1-allylic-2-methyl-glyoxaline chloride system was better than that synthetized in the 1-butyl-2-methyl-glyoxaline chloride system.%采用大分子反应法,将疏水性单体l-溴代十二烷(BD)接枝到羟乙基纤维素(HEC)上,对羟乙基纤维素进行疏水改性,制备了疏水改性羟乙基纤维素(HMHEC)。研究了离子液体种类、反应温度、羟乙基纤维素浓度和BD用量对HMHEC性能的影响。最佳合成条件为:HEC浓度为3%(质量分数),溶解时间1 h,溶解温度100℃,反应时间2 h,反应温度80℃,BD用量为2 mL。在1-烯丙基-2-甲基-咪唑氯盐体系中合成的HMHEC性能好于在1-丁基-2-甲基咪唑氯盐中合成的HMHEC。

  7. 工业大麻秆芯纤维素吸水树脂快速合成及性能研究%Rapid Synthesis and Characterization of Cellulose-Based Absorbent Resin from Industrial Hemp Hurds

    Institute of Scientific and Technical Information of China (English)

    高欣; 陈克利; 张恒; 朱正良; 陈海燕

    2014-01-01

    以“云麻1号”工业大麻秆芯为原料,采用水溶液微波辅助聚合方式将丙烯酸(AA)和N,N-二甲基丙烯酰胺(DMAA)单体接枝到磨浆处理后的纤维素中,制备吸水性树脂.研究两种单体用量比例、引发剂用量、交联剂用量、纤维素磨浆预处理程度、微波功率和时间对吸水树脂吸液率的影响.通过X-射线衍射(XRD)和扫描电镜(SEM)对其结构和形貌进行表征.结果表明,AA和DMAA质量比为1∶0.3,引发剂用量与单体比率为2.0%,交联剂用量与单体总质量比率为0.3%,微波功率300 W,时间400 s,纤维素打浆度为94°SR,制得树脂吸液率较优.%Absorbent resins are synthesized by grafting copolymerization of acrylic acid(AA)and N,N-dimethyl-acrylamide(DMAA)onto the milled cellulose from“Yunma No.1”hemp hurds by microwave-assisted radical re-action in aqueous solution.The factors,such as weight ratio of two monomers,the amount of initiator and cross-linker,beating degree of cellulose,microwave power and time are investigated.The crystallinity change and the surface morphology are characterized by X-ray diffractometer(XRD)and scanning electron microscopy(SEM), respectively.The resin with nearly optimal absorbency is obtained under the copolymerized conditions of weight ratio of AA to DMAA of 1∶0.3 ,initiator to monomers ratio of 2.0%,cross-linker to monomers weight ratio of 0.3%,94°SR cellulose,300 W microwave power for 400 s.

  8. Correlation between lignin physicochemical properties and inhibition to enzymatic hydrolysis of cellulose.

    Science.gov (United States)

    Yang, Qiang; Pan, Xuejun

    2016-06-01

    Using isolated organosolv lignins from hardwood poplar and softwood lodgepole pine with varied physicochemical properties (molecular weight, aliphatic hydroxyl, phenolic hydroxyl, and hydrophobicity), the inhibitory effect of the lignins on enzymatic hydrolysis of cellulose was investigated and the relationship between lignin properties and the inhibitory effect was elucidated. The results indicated that the lignin inhibition to enzymatic hydrolysis of cellulose was closely related to the hydrophobicity and the phenolic hydroxyl groups of the lignin. The overall hydrophobicity of the lignin quantified by contact angle could serve as a predictor of the inhibitory effect of lignin. Hydrophilic modification of the lignin by carboxylation and sulfonation reduced the hydrophobicity by 22-30% and thereby removed the lignin inhibition by 76-96%. Phenolic hydroxyl group was a crucial factor affecting the inhibitory effect of lignin. Blocking free phenolic hydroxyl group by chemical reaction such as hydroxypropylation significantly (65-91%) reduced the inhibitory effect of lignin. Biotechnol. Bioeng. 2016;113: 1213-1224. © 2015 Wiley Periodicals, Inc. © 2015 Wiley Periodicals, Inc.

  9. 温度及pH双敏感性的新型接枝共聚物%Synthesis and Characterization of Novel Temperature and pH Responsive Hydroxylpropyl Cellulose-based Graft Copolymers

    Institute of Scientific and Technical Information of China (English)

    李小军; 尹明辉; 张国亮; 张风宝

    2009-01-01

    In this study, double-hydrophilic hydroxylpropyl cellulose (HPC) based copolymers with poly(Nisopropylaerylamide) (PNIPAM) and poly(acrylic acid) (PAA) as graft chains were synthesized and characterized. The release behavior of drug-loaded micelles was studied. The results show that the hydrophilicity of copolymers improves as the pH increases, whereas the hydrophobicity of copolymers enhances as the temperature increases, and all the phase behaviors are reversible. The diameter of micelles decreases and then increases with pH increase. It shows different micellizing behavior under acidic and basic conditions according to the temperature increase. In vitro release experiments, which used theophylline as a model drug, show that the micelles enhance pH sensitivity in the release process.

  10. 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...

  11. 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).

  12. 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.

  13. 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.

  14. Design, synthesis and antibacterial activities of 5-(pyrazin-2-yl)-4H-1,2,4-triazole-3-thiol derivatives containing Schiff base formation as FabH inhibitory.

    Science.gov (United States)

    Zhang, Fei; Wen, Qing; Wang, She-Feng; Shahla Karim, Baloch; Yang, Yu-Shun; Liu, Jia-Jia; Zhang, Wei-Ming; Zhu, Hai-Liang

    2014-01-01

    A series of novel schiff base derivatives (H(1)-H(20)) containing pyrazine and triazole moiety have been designed and synthesized, and their biological activities were also evaluated as potential inhibitors of β-ketoacyl-acyl carrier protein synthase III (FabH). These compounds were assayed for antibacterial activity against Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, Bacillus subtilis and Bacillus amyloliquefaciens and selected compounds among them were tested for their Escherichia coli FabH inhibitory activity. Based on the biological data, compound H(17) showed the most potent antibacterial activity with MIC values of 0.39-1.56μg/mL against the tested bacterial strains and exhibited the most potent E. coli FabH inhibitory activity with IC50 of 5.2μM, being better than the positive control Kanamycin B with IC50 of 6.3μM. Furthermore, docking simulation was performed to position compound H(17) into the E. coli FabH active site to determine the probable binding conformation. This study indicated that compound H(17) has demonstrated significant E. coli FabH inhibitory activity as a potential antibacterial agent and provides valuable information for the design of E. coli FabH inhibitors.

  15. Synthesis of o-[N-(Substituted benzoyl)-N-methylamino]phenyl Disulfides by the Spontaneous Coupling of N-Methyl-2-mono(substituted phenyl)benzothiazolines in Solution and Their VEGF Inhibitory Activities

    Institute of Scientific and Technical Information of China (English)

    TANG Jian; ZHANG Bei-Na; GE Mei; ZHU Li; WANG Yang; CHEN Ying; XIA Peng

    2008-01-01

    The solid N-methyl-2-mono(substituted phenyl)benzothiazolines (1) are stable and can be stored in atmosphere, whereas they present different behavior in different solvents. They are relatively stable in alcohol and DMSO-H2O. However, in other organic solvents such as acetone, CH2Cl2, CHCl3, EtOAc etc., the oxidation-coupling reactions occurred spontaneously to give the corresponding disulfide dimers 2. The substituents at 2-phenyl rings, reaction temperature and the acidities of the solutions exerted obvious impacts on the reaction rates and yields of 2. 12 sam-ples of N-methyl-2-(substituted phenyi)benzothiazolines (1) and 11 dimers 2 were evaluated in vitro vascular endo-thelial growth factor (VEGF) inhibitory activity in human breast cancer cell MDA-MB-231 with 2-methoxyestra-diol (2-ME) as the positive reference and most of them showed potent VEGF inhibitory activity with the EC50 values of sub-millimolar range. Among them, the compounds 11, li, and 2d showed potent VEGF inhibitory activities and selectivities with EC50 values of 0.07, 32 and >32, respectively, which were about 10 times of those of 2-ME (EC50=0.49 mmol/L, SI=3.37). The results further demonstrated that the scaffolds of 1 and 2 were privileged and merited further investigation as VEGF inhibitors.

  16. Design and synthesis of new potent anticancer benzothiazole amides and ureas featuring pyridylamide moiety and possessing dual B-Raf(V600E) and C-Raf kinase inhibitory activities.

    Science.gov (United States)

    El-Damasy, Ashraf Kareem; Lee, Ju-Hyeon; Seo, Seon Hee; Cho, Nam-Chul; Pae, Ae Nim; Keum, Gyochang

    2016-06-10

    A new series of benzothiazole amide and urea derivatives tethered with the privileged pyridylamide moiety by ether linkage at the 6-position of benzothiazole (22 final compounds) has been designed and synthesized as potent anticancer sorafenib analogs. A selected group of twelve derivatives was appraised for its antiproliferative activity over a panel of 60 human cancer cell lines at a single dose concentration of 10 μM at National Cancer Institute (NCI, USA). Compounds 4b, 5a, 5b and 5d exhibited promising growth inhibitions and thus were further tested in advanced 5-dose testing assay to determine their GI50 values. The cellular based assay results revealed that 3,5-bis-trifluoromethylphenyl (5b) urea member is the best derivative with superior potency and efficacy compared to sorafenib as well as notable extended spectrum activity covering 57 human cancer cell lines. Kinase screening of compound 5b showed its kinase inhibitory effect against both B-Raf(V600E) and C-Raf. Moreover, the most potent derivatives in cells were investigated for their RAF inhibitory activities, and the results were rationalized with the molecular docking study. Profiling of CYP450 and hERG channel inhibitory effects for the active compounds revealed their low possibilities to exhibit undesirable drug-drug interactions and cardiac side effects.

  17. The Arabidopsis cellulose synthase complex: a proposed hexamer of CESA trimers in an equimolar stoichiometry.

    Science.gov (United States)

    Hill, Joseph L; Hammudi, Mustafa B; Tien, Ming

    2014-12-01

    Cellulose is the most abundant renewable polymer on Earth and a major component of the plant cell wall. In vascular plants, cellulose synthesis is catalyzed by a large, plasma membrane-localized cellulose synthase complex (CSC), visualized as a hexameric rosette structure. Three unique cellulose synthase (CESA) isoforms are required for CSC assembly and function. However, elucidation of either the number or stoichiometry of CESAs within the CSC has remained elusive. In this study, we show a 1:1:1 stoichiometry between the three Arabidopsis thaliana secondary cell wall isozymes: CESA4, CESA7, and CESA8. This ratio was determined utilizing a simple but elegant method of quantitative immunoblotting using isoform-specific antibodies and (35)S-labeled protein standards for each CESA. Additionally, the observed equimolar stoichiometry was found to be fixed along the axis of the stem, which represents a developmental gradient. Our results complement recent spectroscopic analyses pointing toward an 18-chain cellulose microfibril. Taken together, we propose that the CSC is composed of a hexamer of catalytically active CESA trimers, with each CESA in equimolar amounts. This finding is a crucial advance in understanding how CESAs integrate to form higher order complexes, which is a key determinate of cellulose microfibril and cell wall properties.

  18. Cellulose-pectin composite hydrogels: Intermolecular interactions and material properties depend on order of assembly.

    Science.gov (United States)

    Lopez-Sanchez, Patricia; Martinez-Sanz, Marta; Bonilla, Mauricio R; Wang, Dongjie; Gilbert, Elliot P; Stokes, Jason R; Gidley, Michael J

    2017-04-15

    Plant cell walls have a unique combination of strength and flexibility however, further investigations are required to understand how those properties arise from the assembly of the relevant biopolymers. Recent studies indicate that Ca(2+)-pectates can act as load-bearing components in cell walls. To investigate this proposed role of pectins, bioinspired wall models were synthesised based on bacterial cellulose containing pectin-calcium gels by varying the order of assembly of cellulose/pectin networks, pectin degree of methylesterification and calcium concentration. Hydrogels in which pectin-calcium assembly occurred prior to cellulose synthesis showed evidence for direct cellulose/pectin interactions from small-angle scattering (SAXS and SANS), had the densest networks and the lowest normal stress. The strength of the pectin-calcium gel affected cellulose structure, crystallinity and material properties. The results highlight the importance of the order of assembly on the properties of cellulose composite networks and support the role of pectin in the mechanics of cell walls. Copyright © 2017 Elsevier Ltd. All rights reserved.

  19. 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.

  20. 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 (<100 nm).

  1. A universal route for the simultaneous extraction and functionalization of cellulose nanocrystals from industrial and agricultural celluloses

    Science.gov (United States)

    Chen, Guo-Yin; Yu, Hou-Yong; Zhang, Cai-Hong; Zhou, Ying; Yao, Ju-Ming

    2016-02-01

    A simple route was designed to extract the cellulose nanocrystals (CNCs) with formate groups from industrial and agricultural celluloses like microcrystalline cellulose (MCC), viscose fiber, ginger fiber, and bamboo fiber. The effect of reaction time on the microstructure and properties of the CNCs was investigated in detail, while microstructure and properties of different CNCs were compared. The rod-like CNCs (MCC) with hundreds of nanometers in length and about 10 nm in width, nanofibrillated CNCs (ginger fiber bamboo fiber) with average width of 30 nm and the length of 1 μm, and spherical CNCs (viscose fiber) with the width of 56 nm were obtained by one-step HCOOH/HCl hydrolysis. The CNCs with improved thermal stability showed the maximum degradation temperature ( T max) of 368.9-388.2 °C due to the introduction of formate groups (reducibility) and the increased crystallinity. Such CNCs may be used as an effective template for the synthesis of nanohybrids or reinforcing material for high-performance nanocomposites.

  2. A universal route for the simultaneous extraction and functionalization of cellulose nanocrystals from industrial and agricultural celluloses

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Guo-Yin; Yu, Hou-Yong, E-mail: phdyu@zstu.edu.cn; Zhang, Cai-Hong [Zhejiang Sci-Tech University, The Key Laboratory of Advanced Textile Materials and Manufacturing Technology of Ministry of Education, College of Materials and Textiles (China); Zhou, Ying; Yao, Ju-Ming, E-mail: yaoj@zstu.edu.cn [Zhejiang Sci-Tech University, National Engineering Lab for Textile Fiber Materials & Processing Technology (China)

    2016-02-15

    A simple route was designed to extract the cellulose nanocrystals (CNCs) with formate groups from industrial and agricultural celluloses like microcrystalline cellulose (MCC), viscose fiber, ginger fiber, and bamboo fiber. The effect of reaction time on the microstructure and properties of the CNCs was investigated in detail, while microstructure and properties of different CNCs were compared. The rod-like CNCs (MCC) with hundreds of nanometers in length and about 10 nm in width, nanofibrillated CNCs (ginger fiber bamboo fiber) with average width of 30 nm and the length of 1 μm, and spherical CNCs (viscose fiber) with the width of 56 nm were obtained by one-step HCOOH/HCl hydrolysis. The CNCs with improved thermal stability showed the maximum degradation temperature (T{sub max}) of 368.9–388.2 °C due to the introduction of formate groups (reducibility) and the increased crystallinity. Such CNCs may be used as an effective template for the synthesis of nanohybrids or reinforcing material for high-performance nanocomposites.

  3. Polyimide Cellulose Nanocrystal Composite Aerogels

    Science.gov (United States)

    Nguyen, Baochau N.; Meador, Mary Ann; Rowan, Stuart; Cudjoe, Elvis; Sandberg, Anna

    2014-01-01

    Polyimide (PI) aerogels are highly porous solids having low density, high porosity and low thermal conductivity with good mechanical properties. They are ideal for various applications including use in antenna and insulation such as inflatable decelerators used in entry, decent and landing operations. Recently, attention has been focused on stimuli responsive materials such as cellulose nano crystals (CNCs). CNCs are environmentally friendly, bio-renewable, commonly found in plants and the dermis of sea tunicates, and potentially low cost. This study is to examine the effects of CNC on the polyimide aerogels. The CNC used in this project are extracted from mantle of a sea creature called tunicates. A series of polyimide cellulose nanocrystal composite aerogels has been fabricated having 0-13 wt of CNC. Results will be discussed.

  4. CELLULOSE DEGRADATION BY OXIDATIVE ENZYMES

    Directory of Open Access Journals (Sweden)

    Maria Dimarogona

    2012-09-01

    Full Text Available Enzymatic degradation of plant biomass has attracted intensive research interest for the production of economically viable biofuels. Here we present an overview of the recent findings on biocatalysts implicated in the oxidative cleavage of cellulose, including polysaccharide monooxygenases (PMOs or LPMOs which stands for lytic PMOs, cellobiose dehydrogenases (CDHs and members of carbohydrate-binding module family 33 (CBM33. PMOs, a novel class of enzymes previously termed GH61s, boost the efficiency of common cellulases resulting in increased hydrolysis yields while lowering the protein loading needed. They act on the crystalline part of cellulose by generating oxidized and non-oxidized chain ends. An external electron donor is required for boosting the activity of PMOs. We discuss recent findings concerning their mechanism of action and identify issues and questions to be addressed in the future.

  5. Cellulose degradation by oxidative enzymes

    Directory of Open Access Journals (Sweden)

    Maria Dimarogona

    2012-09-01

    Full Text Available Enzymatic degradation of plant biomass has attracted intensive research interest for the production of economically viable biofuels. Here we present an overview of the recent findings on biocatalysts implicated in the oxidative cleavage of cellulose, including polysaccharide monooxygenases (PMOs or LPMOs which stands for lytic PMOs, cellobiose dehydrogenases (CDHs and members of carbohydrate-binding module family 33 (CBM33. PMOs, a novel class of enzymes previously termed GH61s, boost the efficiency of common cellulases resulting in increased hydrolysis yields while lowering the protein loading needed. They act on the crystalline part of cellulose by generating oxidized and non-oxidized chain ends. An external electron donor is required for boosting the activity of PMOs. We discuss recent findings concerning their mechanism of action and identify issues and questions to be addressed in the future.

  6. Preparation of 14C Radiolabelled Sodium Carboxymethyl Cellulose

    Institute of Scientific and Technical Information of China (English)

    CHEN; Bao-jun; YANG; Hong-wei; LI; Shuai

    2013-01-01

    Carboxymethyl cellulose(CMC)is a kind of cellulose derivative.CMC has wide applications,including food,daily chemicals,pharmaceutical industry and chemical industry,etc.In order to study the metabolism of CMC,the sodium carboxymethyl cellulose was labelled with 14C.The carboxymethyl cellulose was labelled with 14C by treatment with alkalized cellulose and 14C-

  7. Flexible Photonic Cellulose Nanocrystal Films

    OpenAIRE

    Guidetti, G.; Atifi, S; Vignolini, S; Hamad, WY

    2016-01-01

    The fabrication of self-assembled cellulose nanocrystal (CNC) films of tunable photonic and mechanical properties using a facile, green approach is demonstrated. The combination of tunable flexibility and iridescence can dramatically expand CNC coating and film barrier capabilities for paints and coating applications, sustainable consumer packaging products, as well as effective templates for photonic and optoelectronic materials and structures. CelluForce Inc., Biotechnology and Biologica...

  8. Conversion of cellulosic wastes to liquid fuels

    Energy Technology Data Exchange (ETDEWEB)

    Kuester, J.L.

    1980-09-01

    The current status and future plans for a project to convert waste cellulosic (biomass) materials to quality liquid hydrocarbon fuels is described. The basic approach is indirect liquefaction, i.e., thermal gasification followed by catalytic liquefaction. The indirect approach results in separation of the oxygen in the biomass feedstock, i.e., oxygenated compounds do not appear in the liquid hydrocarbon fuel product. The process is capable of accepting a wide variety of feedstocks. Potential products include medium quality gas, normal propanol, diesel fuel and/or high octane gasoline. A fluidized bed pyrolysis system is used for gasification. The pyrolyzer can be fluidized with recycle pyrolysis gas, steam or recycle liquefaction system off gas or some combination thereof. Tars are removed in a wet scrubber. Unseparated pyrolysis gases are utilized as feed to a modified Fischer-Tropsch reactor. The liquid condensate from the reactor consists of a normal propanol-water phase and a paraffinic hydrocarbon phase. The reactor can be operated to optimize for either product. The following tasks were specified in the statement of work for the contract period: (1) feedstock studies; (2) gasification system optimization; (3) waste stream characterization; and (4) liquid fuels synthesis. In addition, several equipment improvements were implemented.

  9. Assessment of solvents for cellulose dissolution.

    Science.gov (United States)

    Ghasemi, Mohammad; Tsianou, Marina; Alexandridis, Paschalis

    2017-03-01

    A necessary step in the processing of biomass is the pretreatment and dissolution of cellulose. A good solvent for cellulose involves high diffusivity, aggressiveness in decrystallization, and capability of disassociating the cellulose chains. However, it is not clear which of these factors and under what conditions should be improved in order to obtain a more effective solvent. To this end, a newly-developed phenomenological model has been applied to assess the controlling mechanism of cellulose dissolution. Among the findings, the cellulose fibers remain crystalline almost to the end of the dissolution process for decrystallization-controlled kinetics. In such solvents, decreasing the fiber crystallinity, e.g., via pretreatment, would result in a considerable increase in the dissolution rate. Such insights improve the understanding of cellulose dissolution and facilitate the selection of more efficient solvents and processing conditions for biomass. Specific examples of solvents are provided where dissolution is limited due to decrystallization or disentanglement.

  10. Synthesis, crystal structures, molecular docking, in vitro monoamine oxidase-B inhibitory activity of transition metal complexes with 2-{4-[bis (4-fluorophenyl)methyl]piperazin-1-yl} acetic acid

    Science.gov (United States)

    Yang, Dan-dan; Wang, Riu; Zhu, Jin-long; Cao, Qi-yue; Qin, Jie; Zhu, Hai-liang; Qian, Shao-song

    2017-01-01

    Three novel complexes, [Cu(L)2(H2O)](1), [Zn(L)2(H2O)2]·CH3OH·1.5H2O(2), and [Ni(L)2(H2O)1.8]·CH3OH·1.2H2O (3) (HL = 2-{4-[bis(4-fluorophenyl)methyl]pipera-zin-1-yl} acetic acid), were synthesized and structurally determined by single-crystal X-ray diffraction. Molecular docking study preliminarily revealed that complex 1 had potential Monoamine oxidase B inhibitory activity. All acquired compounds were tested against rat brain MAO-B in vitro. In accordance with the result of calculation, it showed complex 1 (IC50 = 1.85 ± 0.31 μM) have good inhibitory activity against MAO-B at the same micromolar concentrations with positive control Iproniazid Phosphate (IP, IC50 = 7.59 ± 1.17 μM). These results indicated that complex 1 was a potent MAO-B inhibitor.

  11. Design and synthesis of ten biphenyl-neolignan derivatives and their in vitro inhibitory potency against cyclooxygenase-1/2 activity and 5-lipoxygenase-mediated LTB4-formation.

    Science.gov (United States)

    Schühly, Wolfgang; Hüfner, Antje; Pferschy-Wenzig, Eva M; Prettner, Elke; Adams, Michael; Bodensieck, Antje; Kunert, Olaf; Oluwemimo, Asije; Haslinger, Ernst; Bauer, Rudolf

    2009-07-01

    A set of ten derivatives of methylhonokiol, an anti-inflammatory active biphenyl-type neolignan from Magnolia grandiflora, has been evaluated for their in vitro cyclooxygenase-1/2 (COX-1/2) inhibitory activity using assays with purified prostaglandin H synthase (PGHS)-1 and PGHS-2 enzymes as well as for their 5-lipoxygenase (5-LOX) mediated LTB(4) formation inhibitory activity using an assay with activated human polymorphonuclear leukocytes. The derivatization reactions included methylation, acetylation, hydrogenation, epoxydation and isomerization. Five of the derivatives are new to science. The most active compound against COX-1 and COX-2 was methylhonokiol with IC(50) values of 0.1 microM, whereas the most active compound against LTB(4) formation was (E)-3'-propenyl-5-(2-propenyl)-biphenyl-2,4'-diol with an IC(50) value of 1.0 microM. Structure-activity relationship studies showed that the polarity of the derivatives plays a crucial role in their activity towards COX-1/2 enzyme and 5-LOX mediated LTB(4) formation.

  12. The synthesis of novel pyrazole-3,4-dicarboxamides bearing 5-amino-1,3,4-thiadiazole-2-sulfonamide moiety with effective inhibitory activity against the isoforms of human cytosolic carbonic anhydrase I and II.

    Science.gov (United States)

    Mert, Samet; Alım, Zuhal; İşgör, Mehmet Mustafa; Beydemir, Şükrü; Kasımoğulları, Rahmi

    2016-10-01

    A series of 1-(3-substituted-phenyl)-5-phenyl-N(3),N(4)-bis(5-sulfamoyl-1,3,4-thiadiazol-2-yl)-1H-pyrazole-3,4-dicarboxamides (4-15) were synthesized. The structures of these pyrazole-sulfonamides were confirmed by FT-IR, (1)H NMR, (13)C NMR and elemental analysis methods. Human cytosolic carbonic anhydrase (CA, EC 4.2.1.1) isozymes (hCA I and II) were purified from erythrocyte cells by affinity chromatography. The inhibitory effects of newly synthesized derivatives (4-15) were investigated in vitro on esterase activities of these isozymes. The Ki values were determined as 0.119-3.999μM for hCA I and 0.084-0.878μM for hCA II. The results showed that the compound 6 for hCA I and the compound 11 for hCA II had the highest inhibitory effect. Beside that, the compound 8 had the lowest inhibition effect on both isozymes.

  13. Alexa Fluor-labeled Fluorescent Cellulose Nanocrystals for Bioimaging Solid Cellulose in Spatially Structured Microenvironments

    Energy Technology Data Exchange (ETDEWEB)

    Grate, Jay W.; Mo, Kai-For; Shin, Yongsoon; Vasdekis, Andreas; Warner, Marvin G.; Kelly, Ryan T.; Orr, Galya; Hu, Dehong; Dehoff, Karl J.; Brockman, Fred J.; Wilkins, Michael J.

    2015-03-18

    Cellulose nanocrystal materials have been labeled with modern Alexa Fluor dyes in a process that first links the dye to a cyanuric chloride molecule. Subsequent reaction with cellulose nanocrystals provides dyed solid microcrystalline cellulose material that can be used for bioimaging and suitable for deposition in films and spatially structured microenvironments. It is demonstrated with single molecular fluorescence microscopy that these films are subject to hydrolysis by cellulose enzymes.

  14. Alteration of in vivo cellulose ribbon assembly by carboxymethylcellulose and other cellulose derivatives

    OpenAIRE

    1982-01-01

    In vivo cellulose ribbon assembly by the Gram-negative bacterium Acetobacter xylinum can be altered by incubation in carboxymethylcellulose (CMC), a negatively charged water-soluble cellulose derivative, and also by incubation in a variety of neutral, water-soluble cellulose derivatives. In the presence of all of these substituted celluloses, normal fasciation of microfibril bundles to form the typical twisting ribbon is prevented. Alteration of ribbon assembly is most extensive in the presen...

  15. Drag Reduction of Bacterial Cellulose Suspensions

    Directory of Open Access Journals (Sweden)

    Satoshi Ogata

    2011-01-01

    Full Text Available Drag reduction due to bacterial cellulose suspensions with small environmental loading was investigated. Experiments were carried out by measuring the pressure drop in pipe flow. It was found that bacterial cellulose suspensions give rise to drag reduction in the turbulent flow range. We observed a maximum drag reduction ratio of 11% and found that it increased with the concentration of the bacterial cellulose suspension. However, the drag reduction effect decreased in the presence of mechanical shear.

  16. Size Effects of Nano-crystalline Cellulose

    Institute of Scientific and Technical Information of China (English)

    Guo Kang LI; Xiao Fang LI; Yong JIANG; Mei Zhen ZENG; En Yong DING

    2003-01-01

    Natural cellulose with the crystal form of cellulose Ⅰ, when treated with condensed lye(e.g. 18%NaOH), can change into new crystal form of cellulose Ⅱ. But the nano-crystallinecellulose(NCC) can do it when only treated with dilute lye (e.g. 1%NaOH) at room temperatureand even can dissolve into slightly concentrated lye (e.g. 4%NaOH).

  17. Cellulose nanomaterials review: structure, properties and nanocomposites

    OpenAIRE

    Moon, Robert J.; Martini, Ashlie; Nairn, John; Simonsen, John; Youngblood, Jeffrey

    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 methodology of composite processing and resulting properties are fully covered, with an emphasis on neat and high fraction...

  18. Chemo-catalytic valorization of cellulose

    Energy Technology Data Exchange (ETDEWEB)

    Palkovits, R. [RWTH Aachen Univ. (Germany). Inst. fuer Technische und Makromolekulare Chemie

    2012-07-01

    Cellulose can be utilized as carbon source for the production of novel platform molecules as well as fuel motifs. Promising transformation strategies cover the hydrolytic hydrogenation or hydrogenolysis of cellulose to sugar alcohols, the hydrolysis of cellulose to glucose followed by dehydration to 5-hydroxymethylfurfural or levulinic acid and the further hydrogenation of levulinic acid to {gamma}-valerolactone. Main challenges result from the high degree of functionalization of cellulosic feedstocks. In line, processes are carried out in liquid phase utilizing rather polar solvents and aiming for a tailored defunctionalisation of these oxygen rich compounds. Consequently, such transformations require novel strategies concerning the development of suitable catalysts and appropriate process concepts. (orig.)

  19. Chemo-catalytic valorization of cellulose

    Energy Technology Data Exchange (ETDEWEB)

    Palkovits, R. [RWTH Aachen Univ. (Germany). Inst. fuer Technische und Makromolekulare Chemie

    2012-07-01

    Cellulose can be utilized as carbon source for the production of novel platform molecules as well as fuel motifs. Promising transformation strategies cover the hydrolytic hydrogenation or hydrogenolysis of cellulose to sugar alcohols, the hydrolysis of cellulose to glucose followed by dehydration to 5-hydroxymethylfurfural or levulinic acid and the further hydrogenation of levulinic acid to {gamma}-valerolactone. Main challenges result from the high degree of functionalization of cellulosic feedstocks. In line, processes are carried out in liquid phase utilizing rather polar solvents and aiming for a tailored defunctionalisation of these oxygen rich compounds. Consequently, such transformations require novel strategies concerning the development of suitable catalysts and appropriate process concepts. (orig.)

  20. Cytocompatible cellulose hydrogels containing trace lignin.

    Science.gov (United States)

    Nakasone, Kazuki; Kobayashi, Takaomi

    2016-07-01

    Sugarcane bagasse was used as a cellulose resource to prepare transparent and flexible cellulose hydrogel films. On the purification process from bagasse to cellulose, the effect of lignin residues in the cellulose was examined for the properties and cytocompatibility of the resultant hydrogel films. The cellulose was dissolved in lithium chloride/N,N-dimethylacetamide solution and converted to hydrogel films by phase inversion. In the purification process, sodium hydroxide (NaOH) treatment time was changed from 1 to 12h. This resulted in cellulose hydrogel films having small amounts of lignin from 1.62 to 0.68%. The remaining lignin greatly affected hydrogel properties. Water content of the hydrogel films was increased from 1153 to 1525% with a decrease of lignin content. Moreover, lower lignin content caused weakening of tensile strength from 0.80 to 0.43N/mm(2) and elongation from 45.2 to 26.5%. Also, similar tendency was observed in viscoelastic behavior of the cellulose hydrogel films. Evidence was shown that the lignin residue was effective for the high strength of the hydrogel films. In addition, scanning probe microscopy in the morphological observation was suggested that the trace lignin in the cellulose hydrogel affected the cellulose fiber aggregation in the hydrogel network. The trace of lignin in the hydrogels also influenced fibroblast cell culture on the hydrogel films. The hydrogel film containing 1.68% lignin showed better fibroblast compatibility as compared to cell culture polystyrene dish used as reference.

  1. Carboxymethylation of Cellulose by Microwave irradiation

    Institute of Scientific and Technical Information of China (English)

    YE Jun; XIONG Jian; SU Yingzhi; XIAO Ping

    2001-01-01

    @@ Cellulose may be readily converted into ethers involving primary and secondary alcohol groups in each monomer unit and the glycosidic bonds. However, these reactions are rather more complicated than with simple substances, because the stereochemistry of the cellulose molecule is such that the vast majority of its hydroxyl groups form intra-chain hydrogen bonds or inter-chain hydrogen bonds with contiguous molecules. Carboxymethylcellulose (CMC) has played an important part in the commercial uses of cellulose derivatives. CMC becomes alkali and water soluble. The polarity can, in fact, be increased by introduction of ionizing groups, ie carboxymethyl group. CMC is generally produced by the reaction of alkali cellulose with chloroacetic acid.

  2. [Supramolecular reorganizations in cellulose during hydration].

    Science.gov (United States)

    Grunin, Iu B; Grunin, L Iu; Talantsev, V I; Nikol'skaia, E A; Masas, D S

    2015-01-01

    The analysis of modern ideas about the structural organization of the cellulose microfibrils is carried out. The mechanism of the formation of additional capillary-porous system of cellulose under moistening is offered. It is established that when the moisture content of cellulose reaches 8-10%, the filling of its micropores occurs with a simultaneous increase in their cross sizes, a specific surface and reduction in the degree of crystallinity of specimens. Within the proposed model of microfibril construction the parameters of supramolecular structure and capillary-porous system of cotton cellulose are determined.

  3. Simultaneous cellulose conversion and hydrogen production assisted by cellulose decomposition under UV-light photocatalysis.

    Science.gov (United States)

    Zhang, Guan; Ni, Chengsheng; Huang, Xiubing; Welgamage, Aakash; Lawton, Linda A; Robertson, Peter K J; Irvine, John T S

    2016-01-28

    Photocatalytic conversion of cellulose to sugars and carbon dioxide with simultaneous production of hydrogen assisted by cellulose decomposition under UV or solar light irradiation was achieved upon immobilization of cellulose onto a TiO2 photocatalyst. This approach enables production of hydrogen from water without using valuable sacrificial agents, and provides the possibility for recovering sugars as liquid fuels.

  4. Liquid crystalline solutions of cellulose in phosphoric acid for preparing cellulose yarns

    NARCIS (Netherlands)

    Boerstoel, H.

    2006-01-01

    The presen thesis describes a new process for manufacturing high tenacity and high modulus cellulose yarns. A new direct solvent for cellulose has been discovered, leading to liquid crystalline solutions. This new solvent, superphosphoric acid, rapidly dissolves cellulose. These liquid crystalline s

  5. Cellulose Nanocrystals as Chiral Inducers: Enantioselective Catalysis and Transmission Electron Microscopy 3D Characterization.

    Science.gov (United States)

    Kaushik, Madhu; Basu, Kaustuv; Benoit, Charles; Cirtiu, Ciprian M; Vali, Hojatollah; Moores, Audrey

    2015-05-20

    Cellulose nanocrystals (CNCs), derived from cellulose, provide us with an opportunity to devise more sustainable solutions to current technological challenges. Enantioselective catalysis, especially heterogeneous, is the preferred method for the synthesis of pure chiral molecules in the fine chemical industries. Cellulose has been long sought as a chiral inducer in enantioselective catalysis. We report herein an unprecedentedly high enantiomeric excess (ee) for Pd patches deposited onto CNCs used as catalysts for the hydrogenation of prochiral ketones in water at room temperature and 4 bar H2. Our system, where CNCs acted as support and sole chiral source, achieved an ee of 65% with 100% conversions. Cryo-electron microscopy, high-resolution transmission electron microscopy, and tomography were used for the first time to study the 3D structure of a metal functionalized CNC hybrid. It established the presence of sub-nanometer-thick Pd patches at the surface of CNCs and provided insight into the chiral induction mechanism.

  6. Conductivity of Cellulose Acetate Membranes from Pandan Duri Leaves (Pandanus tectorius for Li-ion Battery

    Directory of Open Access Journals (Sweden)

    Laksono Endang W.

    2016-01-01

    Full Text Available The purpose of this research is to know the influence of lithium chloride composition on membrane conductivity. Cellulose was extracted from pandan duri leaves (P. tectorius by dilute alkaline and bleaching with 0.5% NaOCl followed by synthesis of cellulose acetate using acetic anhydride as acetylating agent, acetic acid as solvent and sulfuric acid as catalyst. The membranes were prepared by casting polymer solution method and the composition of CA/LiCl were 60/40, 65/35, 70/30, 75/25, 80/20 and 100/0. Structural analysis was carried out by FTIR and X-ray diffraction. The conductivity was measured using Elkahfi 100. The highest conductivity of cellulose acetate membrane was 2.20 × 10-4 S cm-1 that measured at room temperature for 65/35 composition

  7. Cellulose-polymer-Ag nanocomposite fibers for antibacterial fabrics/skin scaffolds.

    Science.gov (United States)

    Raghavendra, Gownolla Malegowd; Jayaramudu, Tippabattini; Varaprasad, Kokkarachedu; Sadiku, Rotimi; Ray, S Sinha; Mohana Raju, Konduru

    2013-04-02

    Natural carbohydrates (polysaccharides): gum acacia (GA) and gaur gum (GG) were employed in dilute solutions: 0.3%, 0.5% and 0.7% (w/v), as effective reductants for the green synthesis of silver nanoparticles (AgNPs) from AgNO3. The formed AgNPs were impregnated into cellulose fibers after confirming their formation by utilizing ultraviolet-visible (UV-vis) spectral studies, Fourier transforms infrared (FTIR) and transmission electron microscopy (TEM). The surface morphology of the developed cellulose-silver nanocomposite fibers (CSNCFs) were examined with scanning electron microscope-energy dispersive spectroscopy (SEM-EDS). The thermal stability and mechanical properties of the CSNCFs were found to be better than cellulose fibers alone. The antibacterial activity of the nanocomposites was studied by inhibition zone method against Escherichia coli, which suggested that the developed CSNCFs can function effectively as anti-microbial agents. Hence, the developed CSNCFs can effectively used for tissue scaffolding.

  8. High Performance Regenerated Cellulose Membranes from Trimethylsilyl Cellulose

    KAUST Repository

    Ali, Ola

    2013-05-01

    Regenerated cellulose (RC) membranes are extensively used in medical and pharmaceutical separation processes due to their biocompatibility, low fouling tendency and solvent resistant properties. They typically possess ultrafiltration and microfiltration separation characteristics, but recently, there have been attempts to widen their pool of applications in nanofiltration processes. In this work, a novel method for preparing high performance composite RC membranes was developed. These membranes reveal molecular weight cut-offs (MWCO) of less than 250 daltons, which possibly put them ahead of all commercial RC membranes and in competition with high performance nanofiltration membranes. The membranes were prepared by acidic hydrolysis of dip-coated trimethylsilyl cellulose (TMSC) films. TMSC, with a degree of silylation (DS) of 2.8, was prepared from microcrystalline cellulose by reaction with hexamethyldisilazane under the homogeneous conditions of LiCl/DMAC solvent system. Effects of parameters, such as coating solution concentration and drying rates, were investigated. It was concluded that higher TMSC concentrations as well as higher solvent evaporation rates favor better MWCOs, mainly due to increase in the selective layer thickness. Successful cross-linking of prepared membranes with glyoxal solutions, in the presence of boric acid as a catalyst, resulted in MWCOs less than 250 daltons. The suitability of this crosslinking reaction for large scale productions was already proven in the manufacturing of durable-press fabrics. For us, the inexpensive raw materials as well as the low reaction times and temperatures were of interest. Moreover, the non-toxic nature of glyoxal is a key advantage in medical and pharmaceutical applications. The membranes prepared in this work are strong candidates for separation of small organic solutes from organic solvents streams in pharmaceutical industries. Their hydrophilicity, compared to typical nanofiltration membranes, offer

  9. Insolubilized enzymes for food synthesis

    Science.gov (United States)

    Marshall, D. L.

    1972-01-01

    Cellulose matrix with numerous enzyme-coated silica particles of colloidal size permanently bound at various sites within matrix was produced that has high activity and possesses requisite physical characteristics for filtration or column operations. Product also allows coupling step in synthesis of edible food to proceed under mild conditions.

  10. 烯丙基胺-细菌纤维素的制备及其动力学研究%Study on the Synthesis and Kinetics of Cellulose-graft-allylamine

    Institute of Scientific and Technical Information of China (English)

    关晓辉; 许颖; 鲁敏; 于磊; 李彦英

    2012-01-01

    Based on the graft polymerization mechanism of Ce4+ triggering free radicals, cellulose-graft-ally-lamine (al-BC) as a new adsorbent was prepared. In this paper, effects of factors on grafting yield were investigated, such as monomer concentration, temperature and time of reaction and at the same time the process of graft dynamics was discussed. The al-BC adsorbent was used to research the adsorption capacity of Pb2+. Results indicate that the graft yield would approach to 18. 22% in the optimal reaction conditions. After analyzing the results of tests, dynamic model of graft rate was deduced. The adsorption capacity of Pb2+ on al-BC was 53. 37%, which was more 37. 53% than that of BC, in the best adsorption conditions.%基于Ce4+引发自由基接枝共聚机理,制备了新型的烯丙基胺-细菌纤维素(al-BC)吸附剂;考察了细菌纤维素(BC)和烯丙基胺加入量、硝酸铈铵(CAN)浓度等对接枝共聚反应的影响并探讨了其接枝动力学过程;以al-BC为吸附剂,研究其对重金属离子pb2 -的吸附性能.结果表明:在CAN浓度25mmol/L、硝酸浓度0.16mol/L、烯丙基胺及BC加入量分别为24mL/L和8g/L、温度40℃、反应时间4h的最优接枝条件下,al-BC接枝率为18.22%;根据实验结果拟合出了反应初期接枝反应动力学方程;在最优吸附条件下,al-BC对pb2+的吸附能力比BC提高了37.53%.

  11. Ethyl Cellulose and Cetrimonium Bromide Assisted Synthesis of Mesoporous, Hexagon Shaped ZnO Nanodisks with Exposed ±{0001} Polar Facets for Enhanced Photovoltaic Performance in Quantum Dot Sensitized Solar Cells.

    Science.gov (United States)

    Chetia, Tridip Ranjan; Ansari, Mohammad Shaad; Qureshi, Mohammad

    2015-06-24

    Hexagon shaped mesoporous zinc oxide nanodisks (ZnO NDs) with exposed ±{0001} polar facets have been synthesized by using ethyl cellulose (EC) and cetrimonium bromide (CTAB) as the capping and structure directing agents. We have characterized ZnO NDs using analytical techniques, such as powder X-ray diffraction (PXRD), diffuse reflectance UV-visible (UV-vis) spectroscopy, photoluminescence (PL) spectroscopy, field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), and Brunauer-Emmett-Teller (BET) surface area analysis and proposed a plausible mechanism for the formation of ZnO NDs. EC molecules form a colloidal solution in a 1-butanol:water (3:1) solvent system having a negative zeta potential (ζ ≈ -32 mV) value which can inhibit CTAB assisted c-axis growth of ZnO crystal and encourage the formation of ZnO NDs. In the control reactions carried out in presence of only CTAB and only EC, formation of hexagonal ZnO nanorods (NRs) and ZnO nanosheets (NSs) composed of numerous ZnO nanoparticles are observed, respectively. Photovoltaic properties of ZnO NDs as compared to ZnO NRs, ZnO NSs, and conventional ZnO nanoparticles (NPs) are investigated by co-sensitizing with CdS/CdSe quantum dots (QDs). An ∼35% increase in power conversion efficiency (PCE, η) is observed in ZnO NDs (η ≈ 4.86%) as compared to ZnO NPs (η ≈ 3.14%) while the values of PCE for ZnO NR and ZnO NS based devices are found to be ∼2.52% and ∼1.64%, respectively. Enhanced photovoltaic performance of the ZnO NDs based solar cell is attributed to an efficient charge separation and collection, boosted by the exposed ±(0001) facets apart from the single crystalline nature, better light-scattering effects, and high BET surface area for sensitizer particle adsorption. Electrochemical impedance spectroscopy (EIS) analysis further reveals that the charge recombination resistance and photoinduced electron lifetime are substantially higher in the ZnO ND based

  12. Pyrolytic sugars from cellulosic biomass

    Science.gov (United States)

    Kuzhiyil, Najeeb

    Sugars are the feedstocks for many promising advanced cellulosic biofuels. Traditional sugars derived from starch and sugar crops are limited in their availability. In principle, more plentiful supply of sugars can be obtained from depolymerization of cellulose, the most abundant form of biomass in the world. Breaking the glycosidic bonds between the pyranose rings in the cellulose chain to liberate glucose has usually been pursued by enzymatic hydrolysis although a purely thermal depolymerization route to sugars is also possible. Fast pyrolysis of pure cellulose yields primarily levoglucosan, an anhydrosugar that can be hydrolyzed to glucose. However, naturally occurring alkali and alkaline earth metals (AAEM) in biomass are strongly catalytic toward ring-breaking reactions that favor formation of light oxygenates over anhydrosugars. Removing the AAEM by washing was shown to be effective in increasing the yield of anhydrosugars; but this process involves removal of large amount of water from biomass that renders it energy intensive and thereby impractical. In this work passivation of the AAEM (making them less active or inactive) using mineral acid infusion was explored that will increase the yield of anhydrosugars from fast pyrolysis of biomass. Mineral acid infusion was tried by previous researchers, but the possibility of chemical reactions between infused acid and AAEM in the biomass appears to have been overlooked, possibly because metal cations might be expected to already be substantially complexed to chlorine or other strong anions that are found in biomass. Likewise, it appears that previous researchers assumed that as long as AAEM cations were in the biomass, they would be catalytically active regardless of the nature of their complexion with anions. On the contrary, we hypothesized that AAEM can be converted to inactive or less active salts using mineral acids. Various biomass feedstocks were infused with mineral (hydrochloric, nitric, sulfuric and

  13. RECYCLING OF VALUELESS PAPER DUST TO A LOW GRADE CELLULOSE ACETATE: EFFECT OF PRETREATMENTS ON ACETYLATION

    Directory of Open Access Journals (Sweden)

    Cheu Peng Leh,

    2012-01-01

    Full Text Available The feasibility of the production of cellulose acetate (CA from recycled paper dust from carton boxes was examined. Two pre-treatments were carried out on the carton box’s paper dust (CPD to improve the pulp properties for better effect of synthesis. The results showed that the acid and oxygen-alkaline pretreatments were capable of increasing the alpha-cellulose content from 80.5 percent to 87.3 percent and 85.3 percent, respectively. Both pre-treatments also decreased the hemicellulose and ash contents by more than 50 percent. The degree of substitution (DS of the resultant CA from pre-treated paper dust was improved from 1.94 to 2.13-2.16. The CA that was synthesized from the recycled paper dust showed comparable DS and had a similar trend of Fourier Transform Infrared (FTIR spectra. Both pretreated pulps also showed an increment in the degree of crystallinity and had maximum degradation effect of temperature when compared to CPD CA. However, all the cellulose acetates produced showed a lower DS and thermal stability compared to commercial cellulose acetate (C CA. The degree of crystallinity of all the cellulose acetate was decreased in comparison to the original material.

  14. Physicochemical characterization of novel Schiff bases derived from developed bacterial cellulose 2,3-dialdehyde.

    Science.gov (United States)

    Keshk, Sherif M A S; Ramadan, Ahmed M; Bondock, Samir

    2015-08-20

    The synthesis of two novel Schiff's bases (cellulose-2,3-bis-[(4-methylene-amino)-benzene-sulfonamide] (5) & cellulose-2,3-bis-[(4-methylene-amino)-N-(thiazol-2-yl)-benzenesulfonamide] (6) via condensation reactions of periodate oxidized developed bacterial cellulose ODBC (2) with sulfa drugs [sulfanilamide (3) & sulfathiazole (4)] was reported. The physicochemical characterization of the condensation products was performed using FTIR, (1)H NMR, (13)C NMR spectral analyses, X-ray diffraction and DTA. The ODBC exhibited the highest degree of oxidation based on the aldehyde group number percentage (82.9%), which confirms the highest reactivity of developed bacterial cellulose [DBC (1)]. The X-ray diffractograms indicated an increase in the interplanar distance of the cellulose Schiff base (6) compared to ODBC (2) due to sulfathiazole (4) inclusion between ODBC (2) sheets corresponding to the 1 1 0 plane. In addition, the aldehyde content of Schiff base (6) was (20.8%) much lower than that of Schiff base (5) (41.5%). These results confirmed the high affinity of sulfathiazole (4) to the ODBC (2) chain, and the substantial changes in the original properties of ODBC were due to these chemical modifications rather than the sulfanilamide (3).

  15. Sucrose synthase affects carbon partitioning to increase cellulose production and altered cell wall ultrastructure.

    Science.gov (United States)

    Coleman, Heather D; Yan, Jimmy; Mansfield, Shawn D

    2009-08-04

    Overexpression of the Gossypium hirsutum sucrose synthase (SuSy) gene under the control of 2 promoters was examined in hybrid poplar (Populus alba x grandidentata). Analysis of RNA transcript abundance, enzyme activity, cell wall composition, and soluble carbohydrates revealed significant changes in the transgenic lines. All lines showed significantly increased SuSy enzyme activity in developing xylem. This activity manifested in altered secondary cell wall cellulose content per dry weight in all lines, with increases of 2% to 6% over control levels, without influencing plant growth. The elevated concentration of cellulose was associated with an increase in cell wall crystallinity but did not alter secondary wall microfibril angle. This finding suggests that the observed increase in crystallinity is a function of altered carbon partitioning to cellulose biosynthesis rather than the result of tension wood formation. Furthermore, the augmented deposition of cellulose in the transgenic lines resulted in thicker xylem secondary cell wall and consequently improved wood density. These findings clearly implicate SuSy as a key regulator of sink strength in poplar trees and demonstrate the tight association of SuSy with cellulose synthesis and secondary wall formation.

  16. Comparison of physical properties of regenerated cellulose films fabricated with different cellulose feedstocks in ionic liquid.

    Science.gov (United States)

    Pang, JinHui; Wu, Miao; Zhang, QiaoHui; Tan, Xin; Xu, Feng; Zhang, XueMing; Sun, RunCang

    2015-05-05

    With the serious "white pollution" resulted from the non-biodegradable plastic films, considerable attention has been directed toward the development of renewable and biodegradable cellulose-based film materials as substitutes of petroleum-derived materials. In this study, environmentally friendly cellulose films were successfully prepared using different celluloses (pine, cotton, bamboo, MCC) as raw materials and ionic liquid 1-ethyl-3-methylimidazolium acetate as a solvent. The SEM and AFM indicated that all cellulose films displayed a homogeneous and smooth surface. In addition, the FT-IR and XRD analysis showed the transition from cellulose I to II was occurred after the dissolution and regeneration process. Furthermore, the cellulose films prepared by cotton linters and pine possessed the most excellent thermal stability and mechanical properties, which were suggested by the highest onset temperature (285°C) and tensile stress (120 MPa), respectively. Their excellent properties of regenerated cellulose films are promising for applications in food packaging and medical materials.

  17. Speculations on the nature of cellulose pyrolysis

    Science.gov (United States)

    F.J. Kilzer; A. Broido

    1965-01-01

    Consideration of the available data on cellulose pyrolysis suggests that, with relative importance depending upon heating rate in the temperature range 200-400°C, very pure cellulose decomposes by two competitive endothermic processes. lt is postulated that an unzipping reaction produces 1,4-anhydro-α-D-glucopyranose which rearranges to give levoglucosan. The other...

  18. Idealized powder diffraction patterns for cellulose polymorphs

    Science.gov (United States)

    Cellulose samples are routinely analyzed by X-ray diffraction to determine their crystal type (polymorph) and crystallinity. However, the connection is seldom made between those efforts and the crystal structures of cellulose that have been determined with synchrotron X-radiation and neutron diffrac...

  19. Nucleic acids encoding a cellulose binding domain

    Energy Technology Data Exchange (ETDEWEB)

    Shoseyov, Oded (Karmey Yosef, IL); Shpiegl, Itai (Rehovot, IL); Goldstein, Marc A. (Davis, CA); Doi, Roy H. (Davis, CA)

    1996-01-01

    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.

  20. 21 CFR 172.870 - Hydroxypropyl cellulose.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Hydroxypropyl cellulose. 172.870 Section 172.870... CONSUMPTION Multipurpose Additives § 172.870 Hydroxypropyl cellulose. The food additive hydroxypropyl... anhydrous basis, not more than 4.6 hydroxypropyl groups per anhydroglucose unit. The additive has a...

  1. Conformational studies of cellulosic fragments by DFT

    Science.gov (United States)

    The study of cellulosic fragments by DFTr is a continuation of our efforts to produce quality structural data that will be valuable to those working in the field of cellulose structure and enzymatic degradation. Using a reduced basis set and density functional DFTr (B3LYP), optimization of cellulosi...

  2. Characterization of cellulose nanofibrillation by micro grinding

    Science.gov (United States)

    Sandeep S. Nair; J.Y. Zhu; Yulin Deng; Arthur J. Ragauskas

    2014-01-01

    A fundamental understanding of the morphological development of cellulose fibers during fibrillation using micro grinder is very essential to develop effective strategies for process improvement and to reduce energy consumption. We demonstrated some simple measures for characterizing cellulose fibers fibrillated at different fibrillation times through the grinder. The...

  3. Diffraction from nonperiodic models of cellulose crystals

    Science.gov (United States)

    Powder and fiber diffraction patterns were calculated for model cellulose crystallites with chains 20 glucose units long. Model sizes ranged from four chains to 169 chains, based on cellulose I' coordinates, and were subjected to various combinations of energy minimization and molecular dynamics (M...

  4. Radiation pretreatment of cellulose for energy production

    Science.gov (United States)

    Dela Rosa, A. M.; Dela Mines, A. S.; Banzon, R. B.; Simbul-Nuguid, Z. F.

    The effect of radiation pretreatment of agricultural cellulosic wastes was investigated through hydrolytic reactions of cellulose. Gamma irradiation significantly increased the acid hydrolysis of rice straw, rice hull and corn husk. The yields of reducing sugar were higher with increasing radiation dose in these materials. The observed radiation effect varied with the cellulosic material but it correlated with neither the cellulose content nor the lignin content. Likewise, the radiation pretreatment accelerated the subsequent enzymatic hydrolysis of rice straw and rice hull by cellulase. The irradiated rice straw appeared to be a better growth medium for the cellulolytic microorganism, Myrothecium verrucaria, than the non-irradiated material. This was attributed to increased digestibility of the cellulose by the microorganism.

  5. BIODEGRADATION OF REGENERATED CELLULOSE FILMS BY FUNGI

    Institute of Scientific and Technical Information of China (English)

    ZHANG Lina; LIU Haiqing; ZHENG Lianshuang; ZHANG Jiayao; DU Yumin; LIU Weili

    1996-01-01

    The biodegradability of Aspergillus niger (A. niger), Mucor (M-305) and Trichoderma (T-311) strains on regenerated cellulose films in media was investigated. The results showed that T-311 strain isolated from soil adhered on the cellulose film fragments has stronger degradation effect on the cellulose film than A. niger strain. The weights, molecular weights and tensile strengths of the cellulose films in both shake culture and solid media decreased with incubation time, accompanied by producing CO2 and saccharides. HPLC, IR and released CO2 analysis indicated that the biodegradation products of the regenerated cellulose films mainly contain oligosaccharides, cellobiose, glucose, arabinose, erythrose, glycerose,glycerol, ethanal, formaldehyde and organic acid, the end products were CO2 and water.After a month, the films were completely decomposed by fungi in the media at 30℃.

  6. Properties of modified carboxymethyl cellulose and its use as bioactive compound.

    Science.gov (United States)

    Basta, Altaf H; El-Saied, Houssni; El-Deftar, Mervat M; El-Henawy, Ahmed A; El-Sheikh, Hussein H; Abdel-Shakour, Essam H; Hasanin, Mohamed S

    2016-11-20

    The present study deals with synthesizing novel cellulose derivative, from modifying the carboxymethyl cellulose with amino phenylpropanoic acid (CMC-APP). The synthesized CMC-APP was evaluated as biological and anti-cancer active compound. The molecular structures of this active compound were built using the HyperChem program 7.5, together with conventional analysis (nitrogen content, FT-IR, and non-isothermal TGA analysis). Optimizing the CMC/APPA ratio was carried out as preliminary assessment step, via undetected antimicrobial activity measurement. The TEM study showed that, the synthesized cellulose CMC-APP derivative in the nano-scale particle size (range from 12.5 to 89.3nm). Among all the tested microorganisms and MCF-7 breast cancer cells, the synthesized nano-cellulose derivative is possible used as safety medicine for microbial infections and cancers. The minimal inhibitory concentration (MIC) for Gram-positive bacteria, and gram-negative bacteria are 48.82μg/mL and 97μg/mL, respectively. While, the unicellular fungi and filamentous fungi are 12.2μg/mL and 97.65μg/mL, respectively. The cytotoxic index (IC50) for MCF-7 breast cancers is 50μg/mL. Moreover, the computational study of ADMET (absorption, distribution, metabolism, elimination and toxic) properties, of the molecules showed that, this investigated nano-compound is good oral bioavailability.

  7. Synthesis,structure and performance characterization of cellulose-based conductive hydrogel%纤维素基导电水凝胶的合成及其结构性能表征

    Institute of Scientific and Technical Information of China (English)

    梁祥涛; 瞿冰; 肖惠宁; 何北海; 钱丽颖

    2014-01-01

    以离子液体(氯化-1-丁基-三甲基咪唑, BMIMCl)溶解微晶纤维素(MCC),以 N,N-亚甲基双丙烯酰胺作为交联剂形成的纤维素水凝胶为基体,同时吡咯(Py)作为导电聚合物单体,制备了纤维素基导电水凝胶。对MCC/PPy复合导电水凝胶的化学结构和表面形貌进行了表征,研究了该导电水凝胶的导电性、溶胀性能和热稳定性。结果表明,PPy 与 MCC 水凝胶形成了具有半互穿网络结构的导电水凝胶,该水凝胶表面呈蜂窝状;其电导率数量级可达10-4~10-3,且对甲苯磺酸钠掺杂可大幅提高其电导率;随着MCC浓度的增加,纤维素水凝胶的平衡溶胀率呈下降趋势,所得导电水凝胶的溶胀率比纯纤维素水凝胶的溶胀率略有下降,但仍能维持500%的水平;此外,该导电水凝胶的热稳定性较纯MCC水凝胶有所下降。%A kind of novel MCC/PPy composite hydrogel has been prepared using the cross-linking network of microcrystalline cellulose (MCC)as the matrix of the hydrogel,which was dissolved in ionic liquid (chloride-1-butyl-3-methylimidazolium,BMIMCl)and cross-linked by N,N-methylene-bis-arcylamide,and pyrrole (Py)as the monomer of conductive polymer.The chemical structure and morphology of the MCC/PPy composite hy-drogel were characterized by FT-IR and SEM,meanwhile,the conductivity,swelling ratio and thermal stability were studied.Results showed that the MCC/PPy composite hydrogel was semi-IPN conductive hydrogel with honeycomb-like structure.Conductivity of the composite hydrogel was between 10-4-10-3 S/cm,and doping of TsONa increased the conductivity significantly.The equilibrium swelling ratio (ESR)decreased with higher MCC content for both pure MCC hyrogel and the composite hydrogel;and ESR of the composite hydrogel could maintain at the level of 500% which was lower than that of the pure MCC hydrogel.Besides,the thermal sta-bility of the composite hydrogel was reduced than the pure MCC hydrogel.

  8. Controlled synthesis of cellulose grafting PDEAEMA brushes by ATRP in ionic liquid [AMIM]Cl%[AMIM]Cl离子液体中纤维素接枝PDEAEMA分子刷的均相可控聚合

    Institute of Scientific and Technical Information of China (English)

    杜凯迪; 唐二军; 袁淼; 刘少杰; 赵地顺

    2015-01-01

    The microcrystalline cellulose-g-poly[2-(diethylamino)ethyl methacrylate] (MCC-g-PDEAEMA) polymer brushes were synthesized under control by atom transfer radical polymerization (ATRP) in the ionic liquid 1-allyl-3-methylimidazolium chloride ([AMIM]Cl). Ethyl alcohol was used as the cosolvent to form a homogeneous system and solve the problem that the functional monomerN,N-diethylamino-2-ethyl methacrylate (DEAEMA) hardly dissolved in [AMIM]Cl. The synthetic mechanism of heterogeneous system and homogeneous system in [AMIM]Cl was analyzed. The experiments showed that the byproduct PDEAEMA in the homogeneous system was reduced and the grafting efficiency of the polymer brushes was improved. Meanwhile, the molecular weight distribution was narrow and ATRP was easily controlled. Optimum reaction conditions in the homogeneous system were attained at CuBr/PMDETA/DEAEMA/ethyl alcohol molar ratio of 1:15:150:300. The grafting efficiency could reach to 78.1%. MCC-g-PDEAEMA was characterized through FTIR spectroscopy,1H NMR spectroscopy and GPC. The results proved that the PDEAEMA side chains were covalently bonded to the MCC backbone and the molecular weight distribution of the polymer brushes were even.%在氯化1-烯丙基-3-甲基咪唑([AMIM]Cl)离子液体中,采用原子转移自由基(ATRP)法接枝改性微晶纤维素,合成了微晶纤维素-g-甲基丙烯酸二乙氨基乙酯(MCC-g-PDEAEMA)聚合物分子刷。通过加入助溶剂形成均相反应体系,解决了功能性单体甲基丙烯酸二乙氨基乙酯(DEAEMA)在[AMIM]Cl离子液体中的溶解问题。分别研究了离子液体中均相与非均相的反应机理,结果表明:在均相体系中,生成的反应副产物PDEAEMA较少,聚合物分子刷的接枝效率较高,分子量分布窄,ATRP 反应可控性好。实验确定了均相体系最佳反应条件:CuBr/PMDETA/ DEAEMA/乙醇的摩尔比为1:15:150:300, MCC-g-PDEAEMA的接枝效率可达78.1%。通过

  9. Biology-oriented drug synthesis (BIODS) of 2-(2-methyl-5-nitro-1H-imidazol-1-yl)ethyl aryl ether derivatives, in vitro α-amylase inhibitory activity and in silico studies.

    Science.gov (United States)

    Taha, Muhammad; Imran, Syahrul; Ismail, Nor Hadiani; Selvaraj, Manikandan; Rahim, Fazal; Chigurupati, Sridevi; Ullah, Hayat; Khan, Fahad; Salar, Uzma; Javid, Muhammad Tariq; Vijayabalan, Shantini; Zaman, Khalid; Khan, Khalid Mohammed

    2017-10-01

    A new library of 2-(2-methyl-5-nitro-1H-imidazol-1-yl)ethyl aryl ether derivatives (1-23) were synthesized and characterized by EI-MS and (1)H NMR, and screened for their α-amylase inhibitory activity. Out of twenty-three derivatives, two molecules 19 (IC50=0.38±0.82µM) and 23 (IC50=1.66±0.14µM), showed excellent activity whereas the remaining compounds, except 10 and 17, showed good to moderate inhibition in the range of IC50=1.77-2.98µM when compared with the standard acarbose (IC50=1.66±0.1µM). A plausible structure-activity relationship has also been presented. In addition, in silico studies was carried out in order to rationalize the binding interaction of compounds with the active site of enzyme. Copyright © 2017 Elsevier Inc. All rights reserved.

  10. Preparation of cellulose from corncobs I: Study on cellulose extraction

    Directory of Open Access Journals (Sweden)

    Pongnoree, J.

    2006-01-01

    Full Text Available The extraction of fat from corncob powder was determined using hexane and 95% ethanol solution for 4, 8 and 12 hrs. The selected powder was subjected to protein separation using 10, 15 and 20% NaOH for 15, 30 and 45 min. The obtained product was then bleached using 10, 15 and 20% H2O2 for 1.5, 3.0 and 4.5 hrs. It was found that the suitable condition for fat extraction was using 95% ethanol for 8 hrs. The optimal condition for protein extraction was using 15% NaOH for 30 min. and the bleaching condition was using 10% H2O2 for 1.5 hrs. The obtained product contained 76.90% cellulose (dry basis and the chemical composition and physical properties were also determined.

  11. Mitigation of Humic Acid Inhibition in Anaerobic Digestion of Cellulose by Addition of Various Salts

    Directory of Open Access Journals (Sweden)

    Samet Azman

    2015-03-01

    Full Text Available Humic compounds are inhibitory to the anaerobic hydrolysis of cellulosic biomass. In this study, the impact of salt addition to mitigate the inhibitory effects of humic compounds was investigated. The experiment was conducted using batch tests to monitor the anaerobic hydrolysis of cellulose in the presence of humic acid. Sodium, potassium, calcium, magnesium and iron salts were tested separately for their efficiency to mitigate humic acid inhibition. All experiments were done under mesophilic conditions (30 °C and at pH 7. Methane production was monitored online, using the Automatic Methane Potential Test System. Methane production, soluble chemical oxygen demand and volatile fatty acid content of the samples were measured to calculate the hydrolysis efficiencies. Addition of magnesium, calcium and iron salts clearly mitigated the inhibitory effects of humic acid and hydrolysis efficiencies reached up to 75%, 65% and 72%, respectively, which were similar to control experiments. Conversely, potassium and sodium salts addition did not mitigate the inhibition and hydrolysis efficiencies were found to be less than 40%. Mitigation of humic acid inhibition via salt addition was also validated by inductively coupled plasma atomic emission spectroscopy analyses, which showed the binding capacity of different cations to humic acid.

  12. Cellulose-Based Nanomaterials for Energy Applications.

    Science.gov (United States)

    Wang, Xudong; Yao, Chunhua; Wang, Fei; Li, Zhaodong

    2017-09-13

    Cellulose is the most abundant natural polymer on earth, providing a sustainable green resource that is renewable, degradable, biocompatible, and cost effective. Recently, nanocellulose-based mesoporous structures, flexible thin films, fibers, and networks are increasingly developed and used in photovoltaic devices, energy storage systems, mechanical energy harvesters, and catalysts components, showing tremendous materials science value and application potential in many energy-related fields. In this Review, the most recent advancements of processing, integration, and application of cellulose nanomaterials in the areas of solar energy harvesting, energy storage, and mechanical energy harvesting are reviewed. For solar energy harvesting, promising applications of cellulose-based nanostructures for both solar cells and photoelectrochemical electrodes development are reviewed, and their morphology-related merits are discussed. For energy storage, the discussion is primarily focused on the applications of cellulose-based nanomaterials in lithium-ion batteries, including electrodes (e.g., active materials, binders, and structural support), electrolytes, and separators. Applications of cellulose nanomaterials in supercapacitors are also reviewed briefly. For mechanical energy harvesting, the most recent technology evolution in cellulose-based triboelectric nanogenerators is reviewed, from fundamental property tuning to practical implementations. At last, the future research potential and opportunities of cellulose nanomaterials as a new energy material are discussed. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Cellulose nanofibrils aerogels generated from jute fibers.

    Science.gov (United States)

    Lin, Jinyou; Yu, Liangbo; Tian, Feng; Zhao, Nie; Li, Xiuhong; Bian, Fenggang; Wang, Jie

    2014-08-30

    In this work, we report the cellulose nanofibrils extracted from the pristine jute fibers via the pretreatments followed by the TEMPO (2,2,6,6-tetramethylpiperidine-1-oxyl radical)-mediated oxidation and mechanical disintegration. The effects of pretreatments by using the NaOH solution and dimethyl sulfoxide solvent on the fiber morphology and macro/micro-structures were investigated by polarizing microscope and synchrotron radiation wide/small-angle X-ray scattering (WAXS/SAXS). The cellulose nanofibrils exhibit a diameter ranging from 5 nm to 20 nm and a length of several micrometers, which have been assembled into cellulose aerogels by the lyophilization of as-prepared nanofibrils dispersions with various concentrations. The results indicated that the hierarchical structures of as-prepared cellulose aerogels were dependent on the dispersion concentrations. The WAXS results show that the typical cellulose aerogels are coexistence of cellulose I and cellulose II, which has a great promise for many potential applications, such as pharmaceutical, liquid filtration, catalysts, bio-nanocomposites, and tissue engineering scaffolds. Copyright © 2014 Elsevier Ltd. All rights reserved.

  14. Utilization of purified cellulose in fiber studies.

    Science.gov (United States)

    Penner, M H; Liaw, E T

    1990-01-01

    Purified cellulose-type fiber products are widely used in experimental nutrition. Their use in a broad spectrum of studies may potentially lead to the acceptance of the misconception that the various commercially available cellulose products are equivalent. In this paper we have attempted to show that this is not the case. The comparative structural data of Table 2 and the compositional data of Olsen et al provide examples which indicate that purified cellulose preparations should not necessarily be considered equivalent. Unfortunately, our current lack of understanding of how fibers are metabolized and how they may affect specific physiological parameters makes it difficult to determine which, if any, of the measurable structural and chemical properties will be of relevance for a given in vivo study. At present, it appears that researchers utilizing/evaluating the consequences of consuming a purified cellulose-type fiber would be prudent to provide at least a limited amount of data on the properties of the cellulose preparation used in their studies. The characterization of the cellulose product may be done by a variety of methods depending on the expertise of the laboratory. The methods and results discussed in this paper provide an example of the type of information which may be obtained from an in vitro characterization of cellulose products.

  15. Enhancement of Cellulose Degradation by Cattle Saliva.

    Science.gov (United States)

    Seki, Yasutaka; Kikuchi, Yukiko; Kimura, Yoshihiro; Yoshimoto, Ryo; Takahashi, Masatoshi; Aburai, Kenichi; Kanai, Yoshihiro; Ruike, Tatsushi; Iwabata, Kazuki; Sugawara, Fumio; Sakai, Hideki; Abe, Masahiko; Sakaguchi, Kengo

    2015-01-01

    Saccharification of cellulose is a promising technique for producing alternative source of energy. However, the efficiency of conversion of cellulose into soluble sugar using any currently available methodology is too low for industrial application. Many additives, such as surfactants, have been shown to enhance the efficiency of cellulose-to-sugar conversion. In this study, we have examined first whether cattle saliva, as an additive, would enhance the cellulase-catalyzed hydrolysis of cellulose, and subsequently elucidated the mechanism by which cattle saliva enhanced this conversion. Although cattle saliva, by itself, did not degrade cellulose, it enhanced the cellulase-catalyzed degradation of cellulose. Thus, the amount of reducing sugar produced increased approximately 2.9-fold by the addition of cattle saliva. We also found that non-enzymatic proteins, which were present in cattle saliva, were responsible for causing the enhancement effect. Third, the mechanism of cattle saliva mediated enhancement of cellulase activity was probably similar to that of the canonical surfactants. Cattle saliva is available in large amounts easily and cheaply, and it can be used without further purification. Thus, cattle saliva could be a promising additive for efficient saccharification of cellulose on an industrial scale.

  16. A novel cellulose hydrogel prepared from its ionic liquid solution

    Institute of Scientific and Technical Information of China (English)

    LI Lu; LIN ZhangBi; YANG Xiao; WAN ZhenZhen; CUI ShuXun

    2009-01-01

    A novel cellulose hydrogel is prepared by regenerating cellulose from its ionic liquid solution. The transparency cellulose hydrogel presents a good chemical stability and an acceptable mechanical property. This non-toxic cellulose hydrogel should be biocompatibie and may be useful in the future as a biomaterial.

  17. Model films of cellulose. I. Method development and initial results

    NARCIS (Netherlands)

    Gunnars, S.; Wågberg, L.; Cohen Stuart, M.A.

    2002-01-01

    This report presents a new method for the preparation of thin cellulose films. NMMO (N- methylmorpholine- N-oxide) was used to dissolve cellulose and addition of DMSO (dimethyl sulfoxide) was used to control viscosity of the cellulose solution. A thin layer of the cellulose solution is spin- coated

  18. Prevalence and trends of cellulosics in pharmaceutical dosage forms.

    Science.gov (United States)

    Mastropietro, David J; Omidian, Hossein

    2013-02-01

    Many studies have shown that cellulose derivatives (cellulosics) can provide various benefits when used in virtually all types of dosage forms. Nevertheless, the popularity of their use in approved drug products is rather unknown. This research reports the current prevalence and trends of use for 15 common cellulosics in prescription drug products. The cellulosics were powdered and microcrystalline cellulose (MCC), ethyl cellulose, hydroxypropyl cellulose (HPC), hydroxyethyl cellulose (HEC), hypromellose (HPMC), HPMC phthalate, HPMC acetate succinate, cellulose acetate (CA), CA phthalate, sodium (Na) and calcium (Ca) carboxymethylcellulose (CMC), croscarmellose sodium (XCMCNa), methyl cellulose, and low substituted HPC. The number of brand drug products utilizing each cellulosics was determined using the online drug index Rxlist. A total of 607 brand products were identified having one or more of the cellulosics as an active or inactive ingredient. An array of various dosage forms was identified and revealed HPMC and MCC to be the most utilized cellulosics in all products followed by XCMCNa and HPC. Many products contained two or more cellulosics in the formulation (42% containing two, 23% containing three, and 4% containing 4-5). The largest combination occurrence was HPMC with MCC. The use of certain cellulosics within different dosage form types was found to contain specific trends. All injectables utilized only CMCNa, and the same with all ophthalmic solutions utilizing HPMC, and otic suspensions utilizing HEC. Popularity and trends regarding cellulosics use may occur based on many factors including functionality, safety, availability, stability, and ease of manufacturing.

  19. Preparation of carboxymethyl cellulose produced from purun tikus (Eleocharis dulcis)

    Science.gov (United States)

    Sunardi, Febriani, Nina Mutia; Junaidi, Ahmad Budi

    2017-08-01

    Sodium carboxymethyl cellulose (Na-CMC) is one of the important modified cellulose, a water-soluble cellulose, which is widely used in many application of food, pharmaceuticals, detergent, paper coating, dispersing agent, and others. The main raw material of modified cellulose is cellulose from wood and cotton. Recently, much attention has been attracted to the use of various agriculture product and by-product, grass, and residual biomass as cellulose and modified cellulose source for addressing an environmental and economic concern. Eleocharis dulcis, commonly known as purun tikus (in Indonesia), is a native aquatic plant of swamp area (wetland) in Kalimantan, which consists of 30-40% cellulose. It is significantly considered as one of the alternative resources for cellulose. The aims of present study were to isolate cellulose from E. dulcis and then to synthesise Na-CMC from isolated cellulose. Preparation of carboxymethyl cellulose from E. dulcis was carried out by an alkalization and etherification process of isolated cellulose, using various concentration of sodium hydroxide (NaOH) and monochloroacetic acid (MCA). The results indicated that the optimum reaction of alkalization was reached at 20% NaOH and etherification at the mass fraction ratio of MCA to cellulose 1.0. The optimum reaction has the highest solubility and degree of substitution. The carboxymethylation process of cellulose was confirmed by Fourier Transform Infrared spectroscopy (FTIR). In addition, changes in crystallinity of cellulose and Na-CMC were evaluated by X-ray diffraction (XRD).

  20. 硝化抑制剂DMPP的合成及在砖红壤中的应用效果%Synthesis of DMPP and Its Inhibitory Effect on Nitrification in Latosol

    Institute of Scientific and Technical Information of China (English)

    史云峰; 张丽莉; 赵牧秋

    2011-01-01

    Based on synthsis of 3,4-dimethylpyrazole phosphate(DMPP) with method of butanone-isopropyl formate,this paper studied the effect of DMPP on nitrification of latosol with aerobic incubation test.The result indicated that DMPP could significantly inhibit the oxidation of soil ammonium,increase soil NH4+-N concentration and dicrease soil NO3——N concentration.With the increasing of dosage,the apparent inhibition rate was decreased and the nitrification inhibitory rate was increased.The reselut of different application also indicated the suitable dosage of DMPP was 0.5% of applied N in latosol.%在应用丁酮-异丙醇甲酸酯法合成3,4-二甲基吡唑磷酸盐(DMPP)的基础上,采用好气培养法,研究了硝化抑制剂DMPP在砖红壤中施用时对土壤硝化作用的影响。结果表明,在砖红壤中施用硝化抑制剂DMPP能显著抑制土壤中NO3--N的比例。土壤表观硝化率随DMPP添加量的增加而降低,硝化抑制率随DMPP添加量的增加而升高。不同添加量处理试验结果表明,砖红壤中施用DMPP的适宜添加量为纯N量的0.5%。

  1. Inhibitory Control in Childhood Stuttering

    Science.gov (United States)

    Eggers, Kurt; De Nil, Luc F.; Van den Bergh, Bea R. H.

    2013-01-01

    Purpose: The purpose of this study was to investigate whether previously reported parental questionnaire-based differences in inhibitory control (IC; Eggers, De Nil, & Van den Bergh, 2010) would be supported by direct measurement of IC using a computer task. Method: Participants were 30 children who stutter (CWS; mean age = 7;05 years) and 30…

  2. The cellulose synthase superfamily in fully sequenced plants and algae

    Directory of Open Access Journals (Sweden)

    Xu Ying

    2009-07-01

    Full Text Available Abstract Background The cellulose synthase superfamily has been classified into nine cellulose synthase-like (Csl families and one cellulose synthase (CesA family. The Csl families have been proposed to be involved in the synthesis of the backbones of hemicelluloses of plant cell walls. With 17 plant and algal genomes fully sequenced, we sought to conduct a genome-wide and systematic investigation of this superfamily through in-depth phylogenetic analyses. Results A single-copy gene is found in the six chlorophyte green algae, which is most closely related to the CslA and CslC families that are present in the seven land plants investigated in our analyses. Six proteins from poplar, grape and sorghum form a distinct family (CslJ, providing further support for the conclusions from two recent studies. CslB/E/G/H/J families have evolved significantly more rapidly than their widely distributed relatives, and tend to have intragenomic duplications, in particular in the grape genome. Conclusion Our data suggest that the CslA and CslC families originated through an ancient gene duplication event in land plants. We speculate that the single-copy Csl gene in green algae may encode a mannan synthase. We confirm that the rest of the Csl families have a different evolutionary origin than CslA and CslC, and have proposed a model for the divergence order among them. Our study provides new insights about the evolution of this important gene family in plants.

  3. Strength and Water Interactions of Cellulose I Filaments Wet-Spun from Cellulose Nanofibril Hydrogels

    Science.gov (United States)

    Lundahl, Meri J.; Cunha, A. Gisela; Rojo, Ester; Papageorgiou, Anastassios C.; Rautkari, Lauri; Arboleda, Julio C.; Rojas, Orlando J.

    2016-07-01

    Hydrogels comprising cellulose nanofibrils (CNF) were used in the synthesis of continuous filaments via wet-spinning. Hydrogel viscosity and spinnability, as well as orientation and strength of the spun filaments, were found to be strongly affected by the osmotic pressure as determined by CNF surface charge and solid fraction in the spinning dope. The tensile strength, Young’s modulus and degree of orientation (wide-angle X-ray scattering, WAXS) of filaments produced without drawing were 297 MPa, 21 GPa and 83%, respectively, which are remarkable values. A thorough investigation of the interactions with water using dynamic vapour sorption (DVS) experiments revealed the role of sorption sites in the stability of the filaments in wet conditions. DVS analysis during cycles of relative humidity (RH) between 0 and 95% revealed major differences in water uptake by the filaments spun from hydrogels of different charge density (CNF and TEMPO-oxidised CNF). It is concluded that the mechanical performance of filaments in the presence of water deteriorates drastically by the same factors that facilitate fibril alignment and, consequently, enhance dry strength. For the most oriented filaments, the maximum water vapour sorption at 95% RH was 39% based on dry weight.

  4. Cellulosic ethanol: status and innovation

    Energy Technology Data Exchange (ETDEWEB)

    Lynd, L; Liang, Xiaoyu; Biddy, Mary; Allee, Andrew; Cai, Hao; Foust, Thomas; Himmel, Michael E.; Laser, Mark; Wang, Michael; Wyman, Charles

    2017-01-01

    Although the purchase price of cellulosic feedstocks is competitive with petroleum on an energy basis, the cost of lignocellulose conversion to ethanol using today’s technology is high. Cost reductions can be pursued via either in-paradigm or new-paradigm innovation. As an example of new-paradigm innovation, consolidated bioprocessing using thermophilic bacteria combined with milling during fermentation (cotreatment) is analyzed. Acknowledging the nascent state of this approach, our analysis indicates potential for radically improved cost competitiveness and feasibility at smaller scale compared to current technology, arising from (a) R&D-driven advances (consolidated bioprocessing with cotreatment in lieu of thermochemical pretreatment and added fungal cellulase), and (b) configurational changes (fuel pellet coproduction instead of electricity, gas boiler(s) in lieu of a solid fuel boiler).

  5. Surface modification of cellulose nanocrystals

    Institute of Scientific and Technical Information of China (English)

    WANG Neng; DING Enyong; CHENG Rongshi

    2007-01-01

    In order to improve the dispersibility of cellulose nanocrystal(CNC) particles,three difierent grafted reactions of acetylation,hydroxyethylation and hydroxypropylation were introduced to modify the CNC surface.The main advantages of these methods were the simple and easily controlled reaction conditions,and the dispersibility of the resulting products was distinctly improved.The properties of the modified CNC were characterized by means of Fourier transform infrared spectroscopy(FT-IR),13 C nuclear magnetic resonance(NMR),transmission electron microscopy(TEM)and thermogravimetric analyses(TGA).The results indicated mat after desiccation,the modification products could be dispersed again in the proper solvents by ultrasonic treatments,and the diameter of their particles had no obvious changes.However,their thermal degradation behaviors were quite different.The initial decomposition temperature of the modified products via hydroxyethylation or hydroxypropylation was lower than that of modified products via acetylation.

  6. Lyocell, The New Generation of Regenerated Cellulose

    Directory of Open Access Journals (Sweden)

    Éva Borbély

    2008-06-01

    Full Text Available For the majority of the last century, commercial routes to regenerated cellulosefibres have coped with the difficulties of making a good cellulose solution by using an easyto dissolve derivative (e.g. xanthane in the case of viscose rayon or complex (e.g.cuprammonium rayon. For the purposes of this paper, advanced cellulosic fibres aredefined as those made from a process involving direct dissolution of cellulose. The firstexamples of such fibres have now been generically designaed as lyocell fibres todistinguish them from rayons, and the first commercial lyocell fibre is Courtaulds’ Tencel.

  7. Cellulose-builder: a toolkit for building crystalline structures of cellulose.

    Science.gov (United States)

    Gomes, Thiago C F; Skaf, Munir S

    2012-05-30

    Cellulose-builder is a user-friendly program that builds crystalline structures of cellulose of different sizes and geometries. The program generates Cartesian coordinates for all atoms of the specified structure in the Protein Data Bank format, suitable for using as starting configurations in molecular dynamics simulations and other calculations. Crystalline structures of cellulose polymorphs Iα, Iβ, II, and III(I) of practically any size are readily constructed which includes parallelepipeds, plant cell wall cellulose elementary fibrils of any length, and monolayers. Periodic boundary conditions along the crystallographic directions are easily imposed. The program also generates atom connectivity file in PSF format, required by well-known simulation packages such as NAMD, CHARMM, and others. Cellulose-builder is based on the Bash programming language and should run on practically any Unix-like platform, demands very modest hardware, and is freely available for download from ftp://ftp.iqm.unicamp.br/pub/cellulose-builder.

  8. Oxidizing Cellulose to 2,3-Dialdehyde Cellulose by Sodium Periodate

    Institute of Scientific and Technical Information of China (English)

    MENG Shuxian; FENG Yaqing; LIANG Zupei; FU Qiang; ZHANG Enzhong

    2005-01-01

    Study on oxidizing cellulose to 2,3-dialdehyde cellulose by sodium periodate (NaIO4) was carried out. The effects of reaction conditions such as pH of solution, temperature, oxidant concentration, oxidation time, the particle size of 2,3-dialdehyde cellulose and alkali treatment temperature on the dialdehyde concentration of cellulose were investigated in detail. The results show that the aldehyde group content was created while reaction temperature and alkali treatment temperature increased.The most principal factors affecting the aldehyde group content of 2,3-dialdehyde cellulose were found out and the best oxidation conditions were as follows: the pH was 2, the reaction temperature was 45 ℃, the mass ratio of cellulose to NaIO4 was 1/2, the reaction time was 4 h, the alkali treatment temperature was 70 ℃ and smaller particle size was 0.80 mm.

  9. Brittle Culm1, a COBRA-like protein, functions in cellulose assembly through binding cellulose microfibrils.

    Science.gov (United States)

    Liu, Lifeng; Shang-Guan, Keke; Zhang, Baocai; Liu, Xiangling; Yan, Meixian; Zhang, Lanjun; Shi, Yanyun; Zhang, Mu; Qian, Qian; Li, Jiayang; Zhou, Yihua

    2013-01-01

    Cellulose represents the most abundant biopolymer in nature and has great economic importance. Cellulose chains pack laterally into crystalline forms, stacking into a complicated crystallographic structure. However, the mechanism of cellulose crystallization is poorly understood. Here, via functional characterization, we report that Brittle Culm1 (BC1), a COBRA-like protein in rice, modifies cellulose crystallinity. BC1 was demonstrated to be a glycosylphosphatidylinositol (GPI) anchored protein and can be released into cell walls by removal of the GPI anchor. BC1 possesses a carbohydrate-binding module (CBM) at its N-terminus. In vitro binding assays showed that this CBM interacts specifically with crystalline cellulose, and several aromatic residues in this domain are essential for binding. It was further demonstrated that cell wall-localized BC1 via the CBM and GPI anchor is one functional form of BC1. X-ray diffraction (XRD) assays revealed that mutations in BC1 and knockdown of BC1 expression decrease the crystallite width of cellulose; overexpression of BC1 and the CBM-mutated BC1s caused varied crystallinity with results that were consistent with the in vitro binding assay. Moreover, interaction between the CBM and cellulose microfibrils was largely repressed when the cell wall residues were pre-stained with two cellulose dyes. Treating wild-type and bc1 seedlings with the dyes resulted in insensitive root growth responses in bc1 plants. Combined with the evidence that BC1 and three secondary wall cellulose synthases (CESAs) function in different steps of cellulose production as revealed by genetic analysis, we conclude that BC1 modulates cellulose assembly by interacting with cellulose and affecting microfibril crystallinity.

  10. Brittle Culm1, a COBRA-like protein, functions in cellulose assembly through binding cellulose microfibrils.

    Directory of Open Access Journals (Sweden)

    Lifeng Liu

    Full Text Available Cellulose represents the most abundant biopolymer in nature and has great economic importance. Cellulose chains pack laterally into crystalline forms, stacking into a complicated crystallographic structure. However, the mechanism of cellulose crystallization is poorly understood. Here, via functional characterization, we report that Brittle Culm1 (BC1, a COBRA-like protein in rice, modifies cellulose crystallinity. BC1 was demonstrated to be a glycosylphosphatidylinositol (GPI anchored protein and can be released into cell walls by removal of the GPI anchor. BC1 possesses a carbohydrate-binding module (CBM at its N-terminus. In vitro binding assays showed that this CBM interacts specifically with crystalline cellulose, and several aromatic residues in this domain are essential for binding. It was further demonstrated that cell wall-localized BC1 via the CBM and GPI anchor is one functional form of BC1. X-ray diffraction (XRD assays revealed that mutations in BC1 and knockdown of BC1 expression decrease the crystallite width of cellulose; overexpression of BC1 and the CBM-mutated BC1s caused varied crystallinity with results that were consistent with the in vitro binding assay. Moreover, interaction between the CBM and cellulose microfibrils was largely repressed when the cell wall residues were pre-stained with two cellulose dyes. Treating wild-type and bc1 seedlings with the dyes resulted in insensitive root growth responses in bc1 plants. Combined with the evidence that BC1 and three secondary wall cellulose synthases (CESAs function in different steps of cellulose production as revealed by genetic analysis, we conclude that BC1 modulates cellulose assembly by interacting with cellulose and affecting microfibril crystallinity.

  11. Cellulose microfibril assembly and orientation in higher plant cells

    Energy Technology Data Exchange (ETDEWEB)

    Mueller, S.C. (Syracuse Univ., NY); Maclachlan, G.A.; Brown, R.M. Jr.

    1983-01-01

    Freeze-fractured plasma membranes of seedlings of Zea mays L., Burpee's Snowcross, and Pisum sativum L., variety Alsaka, contain terminal complex structures and the impressions of microfibrils from the newest cell wall layer.Terminal complex subunits are on the exoplasmic fracture (EF) face, and rosette subunits are on the protoplasmic fracture (PF) face of the membrane. The association of terminal complexes and rosettes with microfibril tips and their association with newly deposited groups of microfibrils is indirect evidence for their role in microfibril assembly. Microtubules may be responsible for certain orientations of microfibrils, particularly the formation of bands of microfibrils in newly deposited wall layers. However, microfibril orienting mechanisms are more complex, involving factors still present during colchicine treatment. Since UDP-glucose is thought to be a precursor of cellulose microfibrils in higher plant cells, EM radioautography was used to determine the site of incorporation of glucose. However, under the conditions used, glucose was only incorporated from UDP-glucose at the surface of cut or damaged pea stem cells, i.e., in vitro. Thus, incorporation of glucose from UDP-glucose was not useful for probing the patterns of cellulose microfibril synthesis in vivo. 18 references, 8 figures.

  12. BIOSYNTHESIS OF BACTERIAL CELLULOSE BY МEDUSOMYCES GISEVII

    OpenAIRE

    E. K. Gladysheva; E. A. Skiba

    2015-01-01

    Summary: Bacterial cellulose is an organic material that is synthesized by microorganisms extracellularly. Bacterial cellulose can be used in various industries. Especially, bacterial cellulose has found its application basically in medicine. The production of bacterial cellulose is a complicated and long process. The principal criterion for the process to be successful is bacterial cellulose to be obtained in a higher yield. Russia is lacking an operating facility to produce bacterial cellul...

  13. Apo- and Cellopentaose-bound Structures of the Bacterial Cellulose Synthase Subunit BcsZ

    Energy Technology Data Exchange (ETDEWEB)

    Mazur, Olga; Zimmer, Jochen (UV)

    2012-10-25

    Cellulose, a very abundant extracellular polysaccharide, is synthesized in a finely tuned process that involves the activity of glycosyl-transferases and hydrolases. The cellulose microfibril consists of bundles of linear {beta}-1,4-glucan chains that are synthesized inside the cell; however, the mechanism by which these polymers traverse the cell membrane is currently unknown. In Gram-negative bacteria, the cellulose synthase complex forms a trans-envelope complex consisting of at least four subunits. Although three of these subunits account for the synthesis and translocation of the polysaccharide, the fourth subunit, BcsZ, is a periplasmic protein with endo-{beta}-1,4-glucanase activity. BcsZ belongs to family eight of glycosyl-hydrolases, and its activity is required for optimal synthesis and membrane translocation of cellulose. In this study we report two crystal structures of BcsZ from Escherichia coli. One structure shows the wild-type enzyme in its apo form, and the second structure is for a catalytically inactive mutant of BcsZ in complex with the substrate cellopentaose. The structures demonstrate that BcsZ adopts an ({alpha}/{alpha}){sub 6}-barrel fold and that it binds four glucan moieties of cellopentaose via highly conserved residues exclusively on the nonreducing side of its catalytic center. Thus, the BcsZ-cellopentaose structure most likely represents a posthydrolysis state in which the newly formed nonreducing end has already left the substrate binding pocket while the enzyme remains attached to the truncated polysaccharide chain. We further show that BcsZ efficiently degrades {beta}-1,4-glucans in in vitro cellulase assays with carboxymethyl-cellulose as substrate.

  14. Overview of bacterial cellulose composites: a multipurpose advanced material.

    Science.gov (United States)

    Shah, Nasrullah; Ul-Islam, Mazhar; Khattak, Waleed Ahmad; Park, Joong Kon

    2013-11-06

    Bacterial cellulose (BC) has received substantial interest owing to its unique structural features and impressive physico-mechanical properties. BC has a variety of applications in biomedical fields, including use as biomaterial for artificial skin, artificial blood vessels, vascular grafts, scaffolds for tissue engineering, and wound dressing. However, pristine BC lacks certain properties, which limits its applications in various fields; therefore, synthesis of BC composites has been conducted to address these limitations. A variety of BC composite synthetic strategies have been developed based on the nature and relevant applications of the combined materials. BC composites are primarily synthesized through in situ addition of reinforcement materials to BC synthetic media or the ex situ penetration of such materials into BC microfibrils. Polymer blending and solution mixing are less frequently used synthetic approaches. BC composites have been synthesized using numerous materials ranging from organic polymers to inorganic nanoparticles. In medical fields, these composites are used for tissue regeneration, healing of deep wounds, enzyme immobilization, and synthesis of medical devices that could replace cardiovascular and other connective tissues. Various electrical products, including biosensors, biocatalysts, E-papers, display devices, electrical instruments, and optoelectronic devices, are prepared from BC composites with conductive materials. In this review, we compiled various synthetic approaches for BC composite synthesis, classes of BC composites, and applications of BC composites. This study will increase interest in BC composites and the development of new ideas in this field.

  15. Optimizing Extraction of Cellulose and Synthesizing Pharmaceutical Grade Carboxymethyl Sago Cellulose from Malaysian Sago Pulp

    National Research Council Canada - National Science Library

    Veeramachineni, Anand; Sathasivam, Thenapakiam; Muniyandy, Saravanan; Janarthanan, Pushpamalar; Langford, Steven; Yan, Lim

    2016-01-01

    .... This work focuses on using sago biomass to obtain cellulose as the raw material, through chemical processing using acid hydrolysis, alkaline extraction, chlorination and bleaching, finally converting...

  16. Fabrication of polyaniline/carboxymethyl cellulose/cellulose nanofibrous mats and their biosensing application

    Energy Technology Data Exchange (ETDEWEB)

    Fu, Jiapeng, E-mail: firgexiao@sina.cn; Pang, Zengyuan, E-mail: pangzengyuan1212@163.com; Yang, Jie, E-mail: young1993@126.com; Huang, Fenglin, E-mail: flhuang@jiangnan.edu.cn; Cai, Yibing, E-mail: yibingcai@jiangnan.edu.cn; Wei, Qufu, E-mail: qfwei@jiangnan.edu.cn

    2015-09-15

    Graphical abstract: - Highlights: • PANI nanorods have been grown onto the surface of CMC/cellulose nanofibers for the fabrication of biosensor substrate material. • The proposed laccase biosensor exhibited a low detection limit and high sensitivity in the detection of catechol. • Hierarchical PANI/CMC/cellulose nanofibers are the promising material in the design of high-efficient biosensors. - Abstract: We report a facile approach to synthesizing and immobilizing polyaniline nanorods onto carboxymethyl cellulose (CMC)-modified cellulose nanofibers for their biosensing application. Firstly, the hierarchical PANI/CMC/cellulose nanofibers were fabricated by in situ polymerization of aniline on the CMC-modified cellulose nanofiber. Subsequently, the PANI/CMC/cellulose nanofibrous mat modified with laccase (Lac) was used as biosensor substrate material for the detection of catechol. PANI/CMC/cellulose nanofibers with highly conductive and three dimensional nanostructure were characterized by scanning electron microscopy (SEM), transmission electron microscope (TEM), Fourier transform infrared spectra (FT-IR), cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). Under optimum conditions, the Lac/PANI/CMC/cellulose/glassy carbon electrode (GCE) exhibited a fast response time (within 8 s), a linear response range from 0.497 μM to 2.27 mM with a high sensitivity and low detection limit of 0.374 μM (3σ). The developed biosensor also displayed good repeatability, reproducibility as well as selectivity. The results indicated that the composite mat has potential application in enzyme biosensors.

  17. Pre-irradiation grafting of cellulose and slightly carboxymethylated cellulose (CMC) fibres

    Energy Technology Data Exchange (ETDEWEB)

    Benke, N. [Institute of Isotopes, HAS, Budapest (Hungary); Takacs, E. [Institute of Isotopes, HAS, Budapest (Hungary)]. E-mail: takacs@iki.kfki.hu; Wojnarovits, L. [Institute of Isotopes, HAS, Budapest (Hungary); Borsa, J. [Budapest University of Technology and Economics, Budapest (Hungary)

    2007-08-15

    Acrylamide, hydroxypropyl acrylate, hydroxypropyl methacrylate and 2-ethylhexyl methacrylate vinyl monomers were grafted onto cellulose as well as onto cellulose of improved accessibility (slightly carboxymethylated cellulose (CMC)) by the pre-irradiation grafting technique. The effect of dose, monomer structure, crosslinking agent and carboxymethylation on the grafting yield was studied and the optimal conditions for the grafting were established. Grafting, with the exception of acrylamide (AAm), decreased the swelling of the samples, which is advantageous for some applications. In case of AAm decrease in swelling was observed only when crosslinking agent was applied. At low doses (<5 kGy) the high accessibility of carboxymethylated cellulose resulted in a higher grafting yield.

  18. Optimizing Extraction of Cellulose and Synthesizing Pharmaceutical Grade Carboxymethyl Sago Cellulose from Malaysian Sago Pulp

    Directory of Open Access Journals (Sweden)

    Anand Kumar Veeramachineni

    2016-06-01

    Full Text Available Sago biomass is an agro-industrial waste produced in large quantities, mainly in the Asia-Pacific region and in particular South-East Asia. This work focuses on using sago biomass to obtain cellulose as the raw material, through chemical processing using acid hydrolysis, alkaline extraction, chlorination and bleaching, finally converting the material to pharmaceutical grade carboxymethyl sago cellulose (CMSC by carboxymethylation. The cellulose was evaluated using Thermogravimetric Analysis (TGA, Infrared Spectroscopy (FTIR, X-Ray Diffraction (XRD, Differential Scanning Calorimetry (DSC and Field Emission Scanning Electronic Microscopy (FESEM. The extracted cellulose was analyzed for cellulose composition, and subsequently modified to CMSC with a degree of substitution (DS 0.6 by typical carboxymethylation reactions. X-ray diffraction analysis indicated that the crystallinity of the sago cellulose was reduced after carboxymethylation. FTIR and NMR studies indicate that the hydroxyl groups of the cellulose fibers were etherified through carboxymethylation to produce CMSC. Further characterization of the cellulose and CMSC were performed using FESEM and DSC. The purity of CMSC was analyzed according to the American Society for Testing and Materials (ASTM International standards. In this case, acid and alkaline treatments coupled with high-pressure defibrillation were found to be effective in depolymerization and defibrillation of the cellulose fibers. The synthesized CMSC also shows no toxicity in the cell line studies and could be exploited as a pharmaceutical excipient.

  19. Conversion of celluloses to proteins. [Use of Cellulomonas and Alcaligenes faecalis

    Energy Technology Data Exchange (ETDEWEB)

    De Leon, C.A.; Joson, L.M.

    1980-01-01

    Cellulosic wastes in the form of sugar cane bagasse was converted to single-cell protein by the action of Cellulomonas species subsequent to hydrolysis by NaOH and(or) autoclaving. As an aid to the process, in order to decompose the inhibitory cellobiose, Alcaligenes faecalis was introduced along with the Cellulomonas. Fungal enzyme production was greatest at the onset of fermentation, while the bacterial cellulases were produced over a more prolonged period, after an initial lag period. Biomass yield showed no correlation with enzyme production. The single-cell protein obtained comprised mainly lysine, methionine, cysteine, glycine, and valine.

  20. Regenerated cellulose-silk fibroin blends fibers.

    Science.gov (United States)

    Marsano, Enrico; Corsini, Paola; Canetti, Maurizio; Freddi, Giuliano

    2008-08-15

    Fibers made of cellulose and silk fibroin at different composition were wet spun from solutions by using N-methylmorpholine N-oxide hydrates (NMMO/H(2)O) as solvent and ethanol as coagulant. Different spinning conditions were used. The fibers were characterized by different techniques: FTIR-Raman, scanning electron microscopy, wide-angle x-ray diffraction, DSC analysis. The results evidence a phase separation in the whole blends compositions. The tensile characterization, however, illustrates that the properties of the blends fibers are higher respect to a linear behaviour between the pure polymers, confirming a good compatibility between cellulose and silk fibroin. The fibers containing 75% of cellulose show better mechanical properties than pure cellulose fibers: modulus of about 23 GPa and strength to break of 307 MPa.

  1. Carboxymethylation of Cellulose by Microwave irradiation

    Institute of Scientific and Technical Information of China (English)

    YE; Jun

    2001-01-01

    Cellulose may be readily converted into ethers involving primary and secondary alcohol groups in each monomer unit and the glycosidic bonds. However, these reactions are rather more complicated than with simple substances, because the stereochemistry of the cellulose molecule is such that the vast majority of its hydroxyl groups form intra-chain hydrogen bonds or inter-chain hydrogen bonds with contiguous molecules. Carboxymethylcellulose (CMC) has played an important part in the commercial uses of cellulose derivatives. CMC becomes alkali and water soluble. The polarity can, in fact, be increased by introduction of ionizing groups, ie carboxymethyl group. CMC is generally produced by the reaction of alkali cellulose with chloroacetic acid.……

  2. Reactive Liftoff of Crystalline Cellulose Particles

    Science.gov (United States)

    Teixeira, Andrew R.; Krumm, Christoph; Vinter, Katherine P.; Paulsen, Alex D.; Zhu, Cheng; Maduskar, Saurabh; Joseph, Kristeen E.; Greco, Katharine; Stelatto, Michael; Davis, Eric; Vincent, Brendon; Hermann, Richard; Suszynski, Wieslaw; Schmidt, Lanny D.; Fan, Wei; Rothstein, Jonathan P.; Dauenhauer, Paul J.

    2015-06-01

    The condition of heat transfer to lignocellulosic biomass particles during thermal processing at high temperature (>400 °C) dramatically alters the yield and quality of renewable energy and fuels. In this work, crystalline cellulose particles were discovered to lift off heated surfaces by high speed photography similar to the Leidenfrost effect in hot, volatile liquids. Order of magnitude variation in heat transfer rates and cellulose particle lifetimes was observed as intermediate liquid cellulose droplets transitioned from low temperature wetting (500-600 °C) to fully de-wetted, skittering droplets on polished surfaces (>700 °C). Introduction of macroporosity to the heated surface was shown to completely inhibit the cellulose Leidenfrost effect, providing a tunable design parameter to control particle heat transfer rates in industrial biomass reactors.

  3. Dissolution enthalpies of cellulose in ionic liquids.

    Science.gov (United States)

    Parviainen, Helena; Parviainen, Arno; Virtanen, Tommi; Kilpeläinen, Ilkka; Ahvenainen, Patrik; Serimaa, Ritva; Grönqvist, Stina; Maloney, Thaddeus; Maunu, Sirkka Liisa

    2014-11-26

    In this work, interactions between cellulose and ionic liquids were studied calorimetrically and by optical microscopy. Two novel ionic liquids (1,5-Diazabicyclo[4.3.0]non-5-enium propionate and N-methyl-1,5-diazabicyclo[4.3.0]non-5-enium dimethyl phosphate) and 1-ethyl-3-methylimidazolium acetate-water mixtures were used as solvents. Optical microscopy served in finding the extent of dissolution and identifying the dissolution pattern of the cellulose sample. Calorimetric studies identified a peak relating to dissolution of cellulose in solvent. The transition did, however, not indicate complete dissolution, but rather dissolution inside fibre or fibrils. This method was used to study differences between four cellulose samples with different pretreatment or origins.

  4. Reactive Liftoff of Crystalline Cellulose Particles.

    Science.gov (United States)

    Teixeira, Andrew R; Krumm, Christoph; Vinter, Katherine P; Paulsen, Alex D; Zhu, Cheng; Maduskar, Saurabh; Joseph, Kristeen E; Greco, Katharine; Stelatto, Michael; Davis, Eric; Vincent, Brendon; Hermann, Richard; Suszynski, Wieslaw; Schmidt, Lanny D; Fan, Wei; Rothstein, Jonathan P; Dauenhauer, Paul J

    2015-06-09

    The condition of heat transfer to lignocellulosic biomass particles during thermal processing at high temperature (>400 °C) dramatically alters the yield and quality of renewable energy and fuels. In this work, crystalline cellulose particles were discovered to lift off heated surfaces by high speed photography similar to the Leidenfrost effect in hot, volatile liquids. Order of magnitude variation in heat transfer rates and cellulose particle lifetimes was observed as intermediate liquid cellulose droplets transitioned from low temperature wetting (500-600 °C) to fully de-wetted, skittering droplets on polished surfaces (>700 °C). Introduction of macroporosity to the heated surface was shown to completely inhibit the cellulose Leidenfrost effect, providing a tunable design parameter to control particle heat transfer rates in industrial biomass reactors.

  5. Structural and morphological characterization of cellulose pulp

    CSIR Research Space (South Africa)

    Ocwelwang, A

    2015-09-01

    Full Text Available Understanding the structure of cellulose is of utmost importance in order to enhance its accessibility and reactivity to chemical processing. Therefore, the aim of this study was to evaluate the effect of ultrasound pretreatment on the structure...

  6. Identifying the catalytic components of cellulose synthase and the maize mixed-linkage beta-glucan synthase

    Energy Technology Data Exchange (ETDEWEB)

    Nicholas C Carpita

    2009-04-20

    Five specific objectives of this project are to develop strategies to identify the genes that encode the catalytic components of "mixed-linkage" (1→3),(1→4)-beta-D-glucans in grasses, to determine the protein components of the synthase complex, and determine the biochemical mechanism of synthesis. We have used proteomic approaches to define intrinsic and extrinsic polypeptides of Golgi membranes that are associated with polysaccharide synthesis and trafficking. We were successful in producing recombinant catalytic domains of cellulose synthase genes and discovered that they dimerize upon concentration, indicating that two CesA proteins form the catalytic unit. We characterized a brittle stalk2 mutant as a defect in a COBRA-like protein that results in compromised lignin-cellulose interactions that decrease tissue flexibility. We used virus-induced gene silencing of barley cell wall polysaccharide synthesis by BSMV in an attempt to silence specific members of the cellulose synthase-like gene family. However, we unexpectedly found that regardless of the specificity of the target gene, whole gene interaction networks were silenced. We discovered the cause to be an antisense transcript of the cellulose synthase gene initiated small interfering RNAs that spread silencing to related genes.

  7. Use of cellulose-containing wastes

    Energy Technology Data Exchange (ETDEWEB)

    Erzinkyan, L.A.; Akhinyan, R.M.; Petrosyan, L.G.; Ngoyan, R.G.

    1981-01-01

    Cellulose containing wastes from various industries were hydrolyzed by different microorganisms to glucose. Penicillium, Aspergillus, Mucor, Fusarium, and Bacterium cellaseum were the most effective organisms, catalyzing complete degradation of cellulose. The hydrolysis product (glucose) promoted the growth of various yeasts: Torulopsis pinus, Candida solani, C. guilliermondii, and C. pelliculosa. The yeast biomass yield reached 60.5% and was rich in protein, vitamins, and minerals.

  8. Cellulose-water interaction: a spectroscopic study

    OpenAIRE

    Lindh, Erik L

    2016-01-01

    The human society of today has a significantly negative impact on the environment and needs to change its way of living towards a more sustainable path if to continue to live on a healthy planet. One path is believed to be an increased usage of naturally degradable and renewable raw materials and, therefore, attention has been focused on the highly abundant biopolymer cellulose. However, a large drawback with cellulose-based materials is the significant change of their mechanical properties w...

  9. Stable Aqueous Foams from Cellulose Nanocrystals and Methyl Cellulose.

    Science.gov (United States)

    Hu, Zhen; Xu, Richard; Cranston, Emily D; Pelton, Robert H

    2016-12-12

    The addition of cellulose nanocrystals (CNC) greatly enhanced the properties of methylcellulose (MC) stabilized aqueous foams. CNC addition decreased air bubble size, initial foam densities and drainage rates. Mixtures of 2 wt % CNC + 0.5 wt % MC gave the lowest density foams. This composition sits near the onset of nematic phase formation and also near the overlap concentration of methylcellulose. More than 94% of the added CNC particles remained in the foam phase, not leaving with the draining water. We propose that the nanoscale CNC particles bind to the larger MC coils both in solution and with MC at the air/water interface, forming weak gels that stabilize air bubbles. Wet CNC-MC foams were sufficiently robust to withstand high temperature (70 °C for 6 h) polymerization of water-soluble monomers giving macroporous CNC composite hydrogels based on acrylamide (AM), 2-hydroxyethyl methacrylate (HEMA), or polyethylene glycol diacrylate (PEGDA). At high temperatures, the MC was present as a fibrillar gel phase reinforced by CNC particles, explaining the very high foam stability. Finally, our CNC-MC foams are based on commercially available forms of CNC and MC, already approved for many applications. This is a "shovel-ready" technology.

  10. Isolation of cellulose microfibrils - An enzymatic approach

    Directory of Open Access Journals (Sweden)

    Sain, M.

    2006-11-01

    Full Text Available Isolation methods and applications of cellulose microfibrils are expanding rapidly due to environmental benefits and specific strength properties, especially in bio-composite science. In this research, we have success-fully developed and explored a novel bio-pretreatment for wood fibre that can substantially improve the microfibril yield, in comparison to current techniques used to isolate cellulose microfibrils. Microfibrils currently are isolated in the laboratory through a combination of high shear refining and cryocrushing. A high energy requirement of these procedures is hampering momentum in the direction of microfibril isolation on a sufficiently large scale to suit potential applications. Any attempt to loosen up the microfibrils by either complete or partial destruction of the hydrogen bonds before the mechanical process would be a step forward in the quest for economical isolation of cellulose microfibrils. Bleached kraft pulp was treated with OS1, a fungus isolated from Dutch Elm trees infected with Dutch elm disease, under different treatment conditions. The percentage yield of cellulose microfibrils, based on their diameter, showed a significant shift towards a lower diameter range after the high shear refining, compared to the yield of cellulose microfibrils from untreated fibres. The overall yield of cellulose microfibrils from the treated fibres did not show any sizeable decrease.

  11. Utilization of biocatalysts in cellulose waste minimization

    Energy Technology Data Exchange (ETDEWEB)

    Woodward, J.; Evans, B.R.

    1996-09-01

    Cellulose, a polymer of glucose, is the principal component of biomass and, therefore, a major source of waste that is either buried or burned. Examples of biomass waste include agricultural crop residues, forestry products, and municipal wastes. Recycling of this waste is important for energy conservation as well as waste minimization and there is some probability that in the future biomass could become a major energy source and replace fossil fuels that are currently used for fuels and chemicals production. It has been estimated that in the United States, between 100-450 million dry tons of agricultural waste are produced annually, approximately 6 million dry tons of animal waste, and of the 190 million tons of municipal solid waste (MSW) generated annually, approximately two-thirds is cellulosic in nature and over one-third is paper waste. Interestingly, more than 70% of MSW is landfilled or burned, however landfill space is becoming increasingly scarce. On a smaller scale, important cellulosic products such as cellulose acetate also present waste problems; an estimated 43 thousand tons of cellulose ester waste are generated annually in the United States. Biocatalysts could be used in cellulose waste minimization and this chapter describes their characteristics and potential in bioconversion and bioremediation processes.

  12. Biohydrogen, bioelectricity and bioalcohols from cellulosic materials

    Energy Technology Data Exchange (ETDEWEB)

    Nissila, M.

    2013-03-01

    The demand for renewable energy is increasing due to increasing energy demand and global warming associated with increasing use of fossil fuels. Renewable energy can be derived from biological production of energy carriers from cellulosic biomass. These biochemical processes include biomass fermentation to hydrogen, methane and alcohols, and bioelectricity production in microbial fuel cells (MFCs). The objective of this study was to investigate the production of different energy carriers (hydrogen, methane, ethanol, butanol, bioelectricity) through biochemical processes. Hydrogen production potential of a hot spring enrichment culture from different sugars was determined, and hydrogen was produced continuously from xylose. Cellulolytic and hydrogenic cultures were enriched on cellulose, cellulosic pulp materials, and on silage at different process conditions. The enrichment cultures were further characterized. The effect of acid pretreatment on hydrogen production from pulp materials was studied and compared to direct pulp fermentation to hydrogen. Electricity and alcohol(s) were simultaneously produced from xylose in MFCs and the exoelectrogenic and alcohologenic enrichment cultures were characterized. In the end, the energy yields obtained from different biochemical processes were determined and compared. In this study, cultures carrying out simultaneous cellulose hydrolysis and hydrogen fermentation were enriched from different sources at different operational conditions. These cultures were successfully utilized for cellulose to hydrogen fermentation in batch systems. Based on these results further research should be conducted on continuous hydrogen production from cellulosic materials.

  13. Cortical Neurodynamics of Inhibitory Control

    OpenAIRE

    Hwang, Kai; Ghuman, Avniel S.; Dara S Manoach; Stephanie R. Jones; Luna, Beatriz

    2014-01-01

    The ability to inhibit prepotent responses is critical for successful goal-directed behaviors. To investigate the neural basis of inhibitory control, we conducted a magnetoencephalography study where human participants performed the antisaccade task. Results indicated that neural oscillations in the prefrontal cortex (PFC) showed significant task modulations in preparation to suppress saccades. Before successfully inhibiting a saccade, beta-band power (18–38 Hz) in the lateral PFC and alpha-b...

  14. Impulsivity: A deficiency of inhibitory control?

    NARCIS (Netherlands)

    Lansbergen, M.M.

    2007-01-01

    Impulsivity has been defined as acting without thinking. Impulsivity can be quantified by impulsivity questionnaires, but also by behavioral paradigms which tax inhibitory control. Previous research has repeatedly demonstrated deficient inhibitory control in psychopathological samples characterized

  15. Cortical neurodynamics of inhibitory control.

    Science.gov (United States)

    Hwang, Kai; Ghuman, Avniel S; Manoach, Dara S; Jones, Stephanie R; Luna, Beatriz

    2014-07-16

    The ability to inhibit prepotent responses is critical for successful goal-directed behaviors. To investigate the neural basis of inhibitory control, we conducted a magnetoencephalography study where human participants performed the antisaccade task. Results indicated that neural oscillations in the prefrontal cortex (PFC) showed significant task modulations in preparation to suppress saccades. Before successfully inhibiting a saccade, beta-band power (18-38 Hz) in the lateral PFC and alpha-band power (10-18 Hz) in the frontal eye field (FEF) increased. Trial-by-trial prestimulus FEF alpha-band power predicted successful saccadic inhibition. Further, inhibitory control enhanced cross-frequency amplitude coupling between PFC beta-band (18-38 Hz) activity and FEF alpha-band activity, and the coupling appeared to be initiated by the PFC. Our results suggest a generalized mechanism for top-down inhibitory control: prefrontal beta-band activity initiates alpha-band activity for functional inhibition of the effector and/or sensory system.

  16. Tyrosinase inhibitory flavonoid from Juniperus communis fruits.

    Science.gov (United States)

    Jegal, Jonghwan; Park, Sang-A; Chung, KiWung; Chung, Hae Young; Lee, Jaewon; Jeong, Eun Ju; Kim, Ki Hyun; Yang, Min Hye

    2016-12-01

    The fruits of Juniperus communis have been traditionally used in the treatment of skin diseases. In our preliminary experiment, the MeOH extract of J. communis effectively suppressed mushroom tyrosinase activity. Three monoflavonoids and five biflavonoids were isolated from J. communis by bioassay-guided isolation and their inhibitory effect against tyrosinase was evaluated. According to the results of all isolates, hypolaetin 7-O-β-xylopyranoside isolated from J. communis exhibited most potent effect of decreasing mushroom tyrosinase activity with an IC50 value of 45.15 μM. Further study provided direct experimental evidence for hypolaetin 7-O-β-D-xylopyranoside-attenuated tyrosinase activity in α-MSH-stimulated B16F10 murine melanoma cell. Hypolaetin 7-O-β-D-xylopyranoside from the EtOAc fraction of J. communis was also effective at suppressing α-MSH-induced melanin synthesis. This is the first report of the enzyme tyrosinase inhibition by J. communis and its constituent. Therapeutic attempts with J. communis and its active component, hypolaetin 7-O-β-D-xylopyranoside, might be useful in treating melanin pigmentary disorders.

  17. Mechanical characterization of cellulose single nanofiber by atomic force microscopy

    Science.gov (United States)

    Zhai, Lindong; Kim, Jeong Woong; Lee, Jiyun; Kim, Jaehwan

    2017-04-01

    Cellulose fibers are strong natural fibers and they are renewable, biodegradable and the most abundant biopolymer in the world. So to develop new cellulose fibers based products, the mechanical properties of cellulose nanofibers would be a key. The atomic microscope is used to measure the mechanical properties of cellulose nanofibers based on 3-points bending of cellulose nanofiber. The cellulose nanofibers were generated for an aqueous counter collision system. The cellulose microfibers were nanosized under 200 MPa high pressure. The cellulose nanofiber suspension was diluted with DI water and sprayed on the silicon groove substrate. By performing a nanoscale 3-points bending test using the atomic force microscopy, a known force was applied on the center of the fiber. The elastic modulus of the single nanofiber is obtained by calculating the fiber deflection and several parameters. The elastic modulus values were obtained from different resources of cellulose such as hardwood, softwood and cotton.

  18. Versatile Molding Process for Tough Cellulose Hydrogel Materials.

    Science.gov (United States)

    Kimura, Mutsumi; Shinohara, Yoshie; Takizawa, Junko; Ren, Sixiao; Sagisaka, Kento; Lin, Yudeng; Hattori, Yoshiyuki; Hinestroza, Juan P

    2015-11-05

    Shape-persistent and tough cellulose hydrogels were fabricated by a stepwise solvent exchange from a homogeneous ionic liquid solution of cellulose exposure to methanol vapor. The cellulose hydrogels maintain their shapes under changing temperature, pH, and solvents. The micrometer-scale patterns on the mold were precisely transferred onto the surface of cellulose hydrogels. We also succeeded in the spinning of cellulose hydrogel fibers through a dry jet-wet spinning process. The mechanical property of regenerated cellulose fibers improved by the drawing of cellulose hydrogel fibers during the spinning process. This approach for the fabrication of tough cellulose hydrogels is a major advance in the fabrication of cellulose-based structures with defined shapes.

  19. Proteome-wide systems analysis of a cellulosic biofuel-producing microbe.

    Science.gov (United States)

    Tolonen, Andrew C; Haas, Wilhelm; Chilaka, Amanda C; Aach, John; Gygi, Steven P; Church, George M

    2011-01-18

    Fermentation of plant biomass by microbes like Clostridium phytofermentans recycles carbon globally and can make biofuels from inedible feedstocks. We analyzed C. phytofermentans fermenting cellulosic substrates by integrating quantitative mass spectrometry of more than 2500 proteins with measurements of growth, enzyme activities, fermentation products, and electron microscopy. Absolute protein concentrations were estimated using Absolute Protein EXpression (APEX); relative changes between treatments were quantified with chemical stable isotope labeling by reductive dimethylation (ReDi). We identified the different combinations of carbohydratases used to degrade cellulose and hemicellulose, many of which were secreted based on quantification of supernatant proteins, as well as the repertoires of glycolytic enzymes and alcohol dehydrogenases (ADHs) enabling ethanol production at near maximal yields. Growth on cellulose also resulted in diverse changes such as increased expression of tryptophan synthesis proteins and repression of proteins for fatty acid metabolism and cell motility. This study gives a systems-level understanding of how this microbe ferments biomass and provides a rational, empirical basis to identify engineering targets for industrial cellulosic fermentation.

  20. Co-processing as a tool to improve aqueous dispersibility of cellulose ethers.

    Science.gov (United States)

    Sharma, Payal; Modi, Sameer R; Bansal, Arvind K

    2015-01-01

    Cellulose ethers are important materials with numerous applications in pharmaceutical industry. They are widely employed as stabilizers and viscosity enhancers for dispersed systems, binders in granulation process and as film formers for tablets. These polymers, however, exhibit challenge during preparation of their aqueous dispersions. Rapid hydration of their surfaces causes formation of a gel that prevents water from reaching the inner core of the particle. Moreover, the surfaces of these particles become sticky, thus leading to agglomeration, eventually reducing their dispersion kinetics. Numerous procedures have been tested to improve dispersibility of cellulose ethers. These include the use of cross-linking agents, alteration in the synthesis process, adjustment of water content of cellulose ether, modification by attaching hydrophobic substituents and co-processing using various excipients. Among these, co-processing has provided the most encouraging results. This review focuses on the molecular mechanisms responsible for the poor dispersibility of cellulose ethers and the role of co-processing technologies in overcoming the challenge. An attempt has been made to highlight various co-processing techniques and specific role of excipients used for co-processing.