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Sample records for cellulose filter membranes

  1. Comparison of polycarbonate and cellulose acetate membrane filters for isolation of Campylobacter concisus from stool samples

    DEFF Research Database (Denmark)

    Linde Nielsen, Hans; Engberg, Jørgen; Ejlertsen, Tove;

    2013-01-01

    One thousand seven hundred ninety-one diarrheic stool samples were cultivated for Campylobacter spp. We found a high prevalence of Campylobacter concisus with use of a polycarbonate filter (n = 114) compared to a cellulose acetate filter (n = 79) (P ... to the commonly used cellulose acetate filter for detection of C. concisus....

  2. Filtering absorption and visual detection of methylene blue by nitrated cellulose acetate membrane

    Energy Technology Data Exchange (ETDEWEB)

    He, Shengbin; Fang, He; Xu, Xiaoping [College of Chemistry, Fuzhou University, Fuzhou (China)

    2016-04-15

    Wastewater-containing industrial dyes are quite harmful since most dyes are stable and toxic to humans. Detection and removing of those dyes from wastewater is necessary to ensure water supply safety. In present work, a nitrated cellulose acetate (NCA) microfiltration membrane was developed for specific absorption and visible detection of methylene blue (MB). The NCA microfiltration membrane overcomes the defect of high driven pressure in nanofiltration or ultrafiltration process. By absorption effect, the NCA membrane also overcomes the defect of low retention rate of traditional microfiltration membrane to dyes. The residual MB can be removed quickly and thoroughly by microfiltration absorption. The microfiltration membrane can also be used for visual detection of MB by concentrating the MB on membrane. The limit of detection is as low as 0.001 mg/L. The detection method is simple and free of large-scale instrument, and can be used as a portable device for spot detection of dye-contaminated water.

  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. Hybrid Filter Membrane

    Science.gov (United States)

    Laicer, Castro; Rasimick, Brian; Green, Zachary

    2012-01-01

    Cabin environmental control is an important issue for a successful Moon mission. Due to the unique environment of the Moon, lunar dust control is one of the main problems that significantly diminishes the air quality inside spacecraft cabins. Therefore, this innovation was motivated by NASA s need to minimize the negative health impact that air-suspended lunar dust particles have on astronauts in spacecraft cabins. It is based on fabrication of a hybrid filter comprising nanofiber nonwoven layers coated on porous polymer membranes with uniform cylindrical pores. This design results in a high-efficiency gas particulate filter with low pressure drop and the ability to be easily regenerated to restore filtration performance. A hybrid filter was developed consisting of a porous membrane with uniform, micron-sized, cylindrical pore channels coated with a thin nanofiber layer. Compared to conventional filter media such as a high-efficiency particulate air (HEPA) filter, this filter is designed to provide high particle efficiency, low pressure drop, and the ability to be regenerated. These membranes have well-defined micron-sized pores and can be used independently as air filters with discreet particle size cut-off, or coated with nanofiber layers for filtration of ultrafine nanoscale particles. The filter consists of a thin design intended to facilitate filter regeneration by localized air pulsing. The two main features of this invention are the concept of combining a micro-engineered straight-pore membrane with nanofibers. The micro-engineered straight pore membrane can be prepared with extremely high precision. Because the resulting membrane pores are straight and not tortuous like those found in conventional filters, the pressure drop across the filter is significantly reduced. The nanofiber layer is applied as a very thin coating to enhance filtration efficiency for fine nanoscale particles. Additionally, the thin nanofiber coating is designed to promote capture of

  5. Filtration properties of bacterial cellulose membranes

    OpenAIRE

    Lehtonen, Janika

    2015-01-01

    Bacterial cellulose has the same molecular formula as cellulose from plant origin, but it is characterized by several unique properties including high purity, crystallinity and mechanical strength. These properties are dependent on parameters such as the bacterial strain used, the cultivation conditions and post-growth processing. The possibility to achieve bacterial cellulose membranes with different properties by varying these parameters could make bacterial cellulose an interesting materi...

  6. Formation of asymmetric cellulose acetate membranes

    NARCIS (Netherlands)

    Bokhorst, H.; Altena, F.W.; Smolders, C.A.

    1981-01-01

    Cellulose acetate membranes were prepared from casting solutions containing dioxane as a solvent and varying concentrations (up to 6%) of maleic acid as an additive. Coagulation took place in water at different temperatures. The effect of these variables on membrane structure and membrane properties

  7. POLYETHERSULFONE COMPOSITE MEMBRANE BLENDED WITH CELLULOSE FIBRILS

    Directory of Open Access Journals (Sweden)

    Ping Qu

    2010-09-01

    Full Text Available Polyethersulfone (PES is a common material used for ultrafiltration (UF membranes, which has good chemical resistance, high mechanical properties, and wide temperature tolerances. The hydrophobic property of the PES membrane seriously limits its application. Cellulose fibrils are composed of micro-sized and nano-sized elements, which have high hydrophilicity, strength, and biodegradation. A composite membrane was prepared by the phase inversion induced by an immersion process. The characteristics of the composite membrane were investigated with Fourier transform infrared spectroscopy (FTIR, X-ray diffraction (XRD, thermogravimetric analysis (TGA, and atomic force microscopy (AFM. The pure water flux of the composite membrane increased dramatically with the increase of cellulose firbils. Mean pore size and porosity were significantly increased. Both mechanical properties and hydrophilicity were enhanced due to the addition of the cellulose firbils.

  8. Cellulose multilayer Membranes manufacture with Ionic liquid

    KAUST Repository

    Livazovic, S.

    2015-05-09

    Membrane processes are considered energy-efficient for water desalination and treatment. However most membranes are based on polymers prepared from fossil petrochemical sources. The development of multilayer membranes for nanofiltration and ultrafiltration, with thin selective layers of naturally available cellulose has been hampered by the availability of non-aggressive solvents. We propose the manufacture of cellulose membranes based on two approaches: (i) silylation, coating from solutions in tetrahydrofuran, followed by solvent evaporation and cellulose regeneration by acid treatment; (ii) casting from solution in 1-ethyl-3-methylimidazolum acetate ([C2mim]OAc), an ionic liquid, followed by phase inversion in water. By these methods porous supports could be easily coated with semi-crystalline cellulose. The membranes were hydrophilic with contact angles as low as 22.0°, molecular weight cut-off as low as 3000 g mol-1 with corresponding water permeance of 13.8 Lm−2 h−1 bar−1. Self-standing cellulose membranes were also manufactured without porous substrate, using only ionic liquid as green solvent. This membrane was insoluble in water, tetrahydrofuran, hexane, N,N-dimethylformamide, 1-methyl-2-pyrrolidinone and N,N-dimethylacetamide.

  9. 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

  10. Process of treating cellulosic membrane and alkaline with membrane separator

    Science.gov (United States)

    Hoyt, H. E.; Pfluger, H. L. (Inventor)

    1970-01-01

    The improvement of water-soluble cellulose ether membranes for use as separators in concentrated alkaline battery cells is discussed. The process of contacting membranes with an aqueous alkali solution of concentration less than that of the alkali solution to be used in the battery but above that at which the membrane is soluble is described.

  11. Preparation of membranes from cellulose obtained of sugarcane bagasse

    International Nuclear Information System (INIS)

    In this work, cellulose obtained from sugarcane bagasse to produce both cellulose and acetylated cellulose to prepare asymmetric membranes. Membranes was procedure used a mixture of materials of DMAc/ LiCl systemic in different conditions. Cellulose and acetylated cellulose were characterized by thermogravimetric (TG), Xray diffraction (XRD) and scanning Electron Microscopy (SEM). Observed less stability thermal of acetylated cellulose when compared of cellulose. All membranes procedure were asymmetric, characterized by presence of a dense skin and porous support can be observed. SEM showed that the morphology of the superficial of membranes depends on the method preparation. (author)

  12. Bacteria/virus filter membrane

    Science.gov (United States)

    Lysaght, M. S.; Goodwin, F.; Roebelen, G.

    1977-01-01

    Hollow acrylate fiber membrane that filters bacterial and viral organisms can be used with closed-cycle life-support systems for underwater habitations or laboratories. Membrane also has applications in fields of medicine, gnotobiotics, pharmaceutical production, and industries and research facilities that require sterile water. Device eliminates need for strong chemicals or sterilizing agents, thereby reducing costs.

  13. Cellulose-Based Membranes for Solutes Fractionation

    Science.gov (United States)

    Anokhina, T. S.; Yushkin, A. A.; Volkov, V. V.; Antonov, S. V.; Volkov, A. V.

    This work was focused on investigation of industrial cellophane film as a membrane material for solvent nanofiltration. The effect of conditioning of cellophane membranes by stepwise changing of composition of ethanol-water binary mixtures (from ethanol to water and from water to ethanol) was studied. It was shown that such treatment leads to an increase of ethanol permeability more than two orders of magnitude over initial untreated film samples. Treated cellophane membranes possess the ethanol permeability coefficient comparable with the values for highly permeability glassy polymers. Investigation of cellophane swelling in water ethanol solutions allowed to conclude that during the treatment formation of porous in the film takes place due to increase of inter chain distances. Observed high ethanol permeability connected with the fact that formed porous structure remains after the replacement of water with ethanol. Also it was shown that rejection coefficients of a number of dyes (MW 350) were in good agreement with the degree of hydrophobicity/hydrophilicity and ability of the solvent to form hydrogen bonding with the solute molecules. It was demonstrated that cellulose-based membranes can be complimentary for other type of the membranes in fractionation of multi-components solutions.

  14. Water-resistant cellulosic filter for aerosol entrapment and water purification, Part I: production of water-resistant cellulosic filter.

    Science.gov (United States)

    Heydarifard, Solmaz; Nazhad, Mousa M; Xiao, Huining; Shipin, Oleg; Olson, James

    2016-07-01

    Synthetic filters are neither biodegradable nor produced from renewable sources. Thus, their disposal has serious environmental impacts. There is a growing desire to produce filters from cellulosic fibers that are renewable, biodegradable, cheap and most importantly recyclable if the contamination is removed. Foam-laid process in papermaking is a promising process for the production of specialty papers. Filters produced using this process are capable of providing products with high specific surface area and tortuous structure favorable for entrapping particulate matters, while providing excellent permeability for incoming gas or liquid. Although the end product fulfills completely the requirement of a filter in a dry environment, it fails completely if it is exposed to a moist environment. This work reports on converting the hydrophilic cellulosic filter into a hydrophobic product without disturbing its original structure. PMID:26683534

  15. Resolution of Dialyzer Membrane-Associated Thrombocytopenia with Use of Cellulose Triacetate Membrane: A Case Report

    OpenAIRE

    Feyisayo Olafiranye; Win Kyaw; Oladipupo Olafiranye

    2011-01-01

    Blood and dialyzer membrane interaction can cause significant thrombocytopenia through the activation of complement system. The extent of this interaction determines the biocompatibility of the membrane. Although the newer synthetic membranes have been shown to have better biocompatibility profile than the cellulose-based membranes, little is known about the difference in biocompatibility between synthetic membrane and modified cellulose membrane. Herein, we report a case of a patient on hemo...

  16. Improvement on filterability in the aerobic treatment of carboxymethyl cellulose (CMC wastewater

    Directory of Open Access Journals (Sweden)

    Qing Pei Ye

    2014-01-01

    Full Text Available CMC is chemically modified from natural cellulose and widely applied in various industries. CMC wastewater consists mainly of sodium glycolate, sodium chloride and water. With extremely high COD and salinity, high concentration CMC wastewater can’t be biologically treated, but with COD and salinity around 15000 mg/L and 30000 mg/L respectively, low concentration CMC wastewater can be aerobically treated. In a CMC factory, the treatment of low concentration wastewater with aerobic MBR was successful except for one serious problem: poor filterability. Two trial solutions: adding micronutrients and applying MBBR were expected to improve the filterability. In the experiment, adding micronutrients was achieved by mixing filtered natural water into the wastewater, rather than dosing chemicals into it. The treatment efficiency of both solutions was close, but adding micronutrients showed distinguished performance in improving filterability, which includes higher filtration flux and slighter membrane fouling. Adding micronutrients also effectively improved the filterability under severe salinity shock.

  17. Ultrafiltration and Nanofiltration Multilayer Membranes Based on Cellulose

    KAUST Repository

    Livazovic, Sara

    2016-06-09

    Membrane processes are considered energy-efficient for water desalination and treatment. However most membranes are based on polymers prepared from fossil petrochemical sources. The development of multilayer membranes for nanofiltration and ultrafiltration, with thin selective layers of naturally available cellulose, has been hampered by the availability of non-aggressive solvents. We propose the manufacture of cellulose membranes based on two approaches: (i) silylation, coating from solutions in tetrahydrofuran, followed by solvent evaporation and cellulose regeneration by acid treatment; (ii) casting from solution in 1-ethyl-3-methylimidazolum acetate ([C2mim]OAc), an ionic liquid, followed by phase inversion in water. In the search for less harsh, greener membrane manufacture, the combination of cellulose and ionic liquid is of high interest. Due to the abundance of OH groups and hydrophilicity, cellulose-based membranes have high permeability and low fouling tendency. Membrane fouling is one of the biggest challenges in membrane industry and technology. Accumulation and deposition of foulants onto the surface reduce membrane efficiency and requires harsh chemical cleaning, therefore increasing the cost of maintenance and replacement. In this work the resistance of cellulose 5 membranes towards model organic foulants such as Suwanee River Humic Acid (SRHA) and crude oil have been investigated. Cellulose membrane was tested in this work for oil-water (o/w) separation and exhibited practically 100 % oil rejection with good flux recovery ratio and membrane resistivity. The influence of anionic, cationic and ionic surfactant as well as pH and crude oil concentration on oil separation was investigated, giving a valuable insight in experimental and operational planning.

  18. Cellulose microfibril deposition: coordinated activity at the plant plasma membrane

    NARCIS (Netherlands)

    Lindeboom, J.J.; Mulder, B.; Vos, J.W.; Ketelaar, M.J.; Emons, A.M.C.

    2008-01-01

    Plant cell wall production is a membrane-bound process. Cell walls are composed of cellulose microfibrils, embedded inside a matrix of other polysaccharides and glycoproteins. The cell wall matrix is extruded into the existing cell wall by exocytosis. This same process also inserts the cellulose syn

  19. Aqueous alkali metal hydroxide insoluble cellulose ether membrane

    Science.gov (United States)

    Hoyt, H. E.; Pfluger, H. L. (Inventor)

    1969-01-01

    A membrane that is insoluble in an aqueous alkali metal hydroxide medium is described. The membrane is a resin which is a water-soluble C2-C4 hydroxyalkyl cellulose ether polymer and an insolubilizing agent for controlled water sorption, a dialytic and electrodialytic membrane. It is particularly useful as a separator between electrodes or plates in an alkaline storage battery.

  20. Preparation of succinylated cellulose membranes for functionalization purposes.

    Science.gov (United States)

    Ribeiro-Viana, Renato M; Faria-Tischer, Paula C S; Tischer, Cesar A

    2016-09-01

    The anhydroglucose chains of cellulose possess hydroxyls that facilitate different chemical modification strategies to expand on, or provide new applications for membranes produced by the bacteria Gluconacetobacter xylinus. Conjugation with biomolecules such as proteins, especially by the amine groups, is of great value and interest for the production of biomaterial derivatives from bacterial cellulose. To assist in these modifications, cellulose was succinylated in order to prevent steric hindrance and to create an attachment point for conjugation. Bacterial cellulose membranes were first treated in dichloromethane and reacted with succinic anhydride through a series of conditions. The membrane structure remained intact after these first processes and the product was confirmed by Infra-Red spectroscopy and solid state nuclear magnetic resonance and characterized by X-ray diffraction, thermogravimetry and atomic force microscopy. Hydrolyzed collagen was used as a model protein of interest to be conjugated to these membranes, which furnished a biomaterial functionalized over its surface. PMID:27185111

  1. Performance of membrane filters used for TEM analysis of asbestos.

    Science.gov (United States)

    Webber, James S; Czuhanich, Alex G; Carhart, Laurie J

    2007-10-01

    This article presents findings related to characteristics of membrane filters that can affect the recovery of asbestos and the quality of preparations for transmission electron microscopy (TEM) analysis. Certain applications and preparation steps can lead to unacceptable performance of membrane filters used in analysis of asbestos by TEM. Unless substantial care is used in the collapsing of mixed-cellulose ester (MCE) filters with an acetone hot block, grid preparations can suffer and fiber recoveries can be compromised. Calibration of the etching depth of MCE filters, especially at differing locations in an asher's chamber, is critical for reliable fiber recovery. Excessive etching of MCE filters with aerosol-deposited asbestos can lead to loss of short fibers, while insufficient etching of MCE filters with aqueous-deposited asbestos can, paradoxically, also lead to loss of short fibers. Interlaboratory precision on MCE filters is improved by aerosol-deposited asbestos, as opposed to aqueous deposition. In comparison, straightforward preparation, improved solvents, and reduced contamination make PC filters an increasingly acceptable alternative. Variations in the geometric configuration during application of carbon films can lead to fiber loss and unacceptable grid quality for either type of filter. PMID:17763069

  2. Self-supported silver nanoparticles containing bacterial cellulose membranes

    International Nuclear Information System (INIS)

    Hydrated bacterial cellulose (BC) membranes obtained from cultures of Acetobacter xylinum were used in the preparation of silver nanoparticles containing cellulose membranes. In situ preparation of Ag nanoparticles was achieved from the hydrolytic decomposition of silver triethanolamine (TEA) complexes. Scanning electron microscopy (SEM) images and X-ray diffraction (XRD) patterns both lead to the observation of spherical metallic silver particles with mean diameter of 8 nm well adsorbed onto the BC fibriles

  3. Self-supported silver nanoparticles containing bacterial cellulose membranes

    Energy Technology Data Exchange (ETDEWEB)

    Barud, Hernane S.; Barrios, Celina; Regiani, Thais; Marques, Rodrigo F.C. [Institute of Chemistry-UNESP, CP 355, Zip 14801-970, Araraquara, SP, 14801-970 (Brazil); Verelst, Marc; Dexpert-Ghys, Jeannette [Centre d' Elaboration de Materiaux et d' Etudes Structurales, CEMES, UPR No. 8011 - Universite Toulouse III, B.P. 94347, 29 rue Jeanne Marvig, 31055 Toulouse Cedex (France); Messaddeq, Younes [Institute of Chemistry-UNESP, CP 355, Zip 14801-970, Araraquara, SP, 14801-970 (Brazil); Ribeiro, Sidney J.L. [Institute of Chemistry-UNESP, CP 355, Zip 14801-970, Araraquara, SP, 14801-970 (Brazil)], E-mail: sidney@iq.unesp.br

    2008-05-01

    Hydrated bacterial cellulose (BC) membranes obtained from cultures of Acetobacter xylinum were used in the preparation of silver nanoparticles containing cellulose membranes. In situ preparation of Ag nanoparticles was achieved from the hydrolytic decomposition of silver triethanolamine (TEA) complexes. Scanning electron microscopy (SEM) images and X-ray diffraction (XRD) patterns both lead to the observation of spherical metallic silver particles with mean diameter of 8 nm well adsorbed onto the BC fibriles.

  4. In-vitro Degradation Behaviour of Irradiated Bacterial Cellulose Membrane

    Directory of Open Access Journals (Sweden)

    D. Darwis

    2012-08-01

    Full Text Available Bacterial cellulose membrane synthesized by Acetobacter xylinum in coconut water medium has potential application for Guided bone Regeneration. However, this membrane may not meet some application requirements due to its low biodegradation properties. In this paper, incorporation of gamma irradiation into the membrane is a developed strategy to increase its biodegradability properties. The in–vitro degradation study in synthetic body fluid (SBF of the irradiated membrane has been analyzed during periods of 6 months by means of weight loss, mechanical properties and scanning electron microscopy observation compared to that the un-irradiated one. The result showed that weight loss of irradiated membrane with 25 kGy and 50 kGy and immersed in SBF solution for 6 months reached 18% and 25% respectively. While un-irradiated membrane did not give significant weight loss. Tensile strength of membranes decreases with increasing of irradiation dose and further decreases in tensile strength is observed when irradiated membrane was followed by immersion in SBF solution. Microscope electron image of cellulose membranes shows that un-irradiated bacterial cellulose membrane consists of dense ultrafine fibril network structures, while irradiation result in cleavage of fibrils network of cellulose. The fibrils network become loosely after irradiated membrane immersed in SBF solution due to released of small molecular weight carbohydrates formed during by irradiation from the structure

  5. In-vitro Degradation Behaviour of Irradiated Bacterial Cellulose Membrane

    International Nuclear Information System (INIS)

    Bacterial cellulose membrane synthesized by Acetobacter xylinum in coconut water medium has potential application for Guided bone Regeneration. However, this membrane may not meet some application requirements due to its low biodegradation properties. In this paper, incorporation of gamma irradiation into the membrane is a developed strategy to increase its biodegradability properties. The in-vitro degradation study in synthetic body fluid (SBF) of the irradiated membrane has been analyzed during periods of 6 months by means of weight loss, mechanical properties and scanning electron microscopy observation compared to that the un-irradiated one. The result showed that weight loss of irradiated membrane with 25 kGy and 50 kGy and immersed in SBF solution for 6 months reached 18% and 25% respectively. While un-irradiated membrane did not give significant weight loss. Tensile strength of membranes decreases with increasing of irradiation dose and further decreases in tensile strength is observed when irradiated membrane was followed by immersion in SBF solution. Microscope electron image of cellulose membranes shows that un-irradiated bacterial cellulose membrane consists of dense ultrafine fibril network structures, while irradiation result in cleavage of fibrils network of cellulose. The fibrils network become loosely after irradiated membrane immersed in SBF solution due to released of small molecular weight carbohydrates formed during by irradiation from the structure (author)

  6. Immobilization of Glucose Oxidase on Cellulose/Cellulose Acetate Membrane and its Detection by Scanning Electrochemical Microscope (SECM)

    Institute of Scientific and Technical Information of China (English)

    Jin Sheng ZHAO; Zhen Yu YANG; Yi He ZHANG; Zheng Yu YANG

    2004-01-01

    Cellulose/cellulose acetate membranes were prepared and functionalized by introducing amino group on it, and then immobilized the glucose oxidase (Gox) on the functionalizd membrane. SECM was applied for the detection of enzyme activity immobilized on the membrane. Immobilized biomolecules on such membranes was combined with analysis apparatus and can be used in bioassays.

  7. Filterability and Sludge Concentration in Membrane Bioreactors

    OpenAIRE

    Lousada-Ferreira, M

    2011-01-01

    The Thesis entitled “Filterability and Sludge Concentration in Membrane Bioreactors” aims at explaining the relation between Mixed Liquid Suspended Solids (MLSS) concentration, the amount of solids in the wastewater being treated, also designated as sludge, and filterability, being the ability of the sludge to be filtrated through a membrane, in a wastewater treatment system designated as Membrane Bioreactor (MBR). An MBR is a wastewater treatment system that combines an activated sludge proc...

  8. Optically transparent membrane based on bacterial cellulose/polycaprolactone

    Directory of Open Access Journals (Sweden)

    H. S. Barud

    2013-01-01

    Full Text Available Optically transparent membranes from bacterial cellulose (BC/polycaprolactone (PCL have been prepared by impregnation of PCL acetone solution into dried BC membranes. UV-Vis measurements showed an increase on transparency in BC/PCL membrane when compared with pristine BC. The good transparency of the BC/PCL can be related to the presence of BC nanofibers associated with deposit of PCL nano-sized spherulites which are smaller than the wavelength of visible light and practically free of light scattering. XRD results show that cellulose type I structure is preserved inside the BC/PCL membrane, while the mechanical properties suggested indicated that PCL acts as a plasticizer for the BC membrane. The novel BC/PCL membrane could be used for preparation of fully biocompatible flexible display and biodegradable food packaging.

  9. FRACTIONATION OF HYDROLYZED MICROCRYSTALLINE CELLULOSE BY ULTRAFILTRATION MEMBRANE

    OpenAIRE

    NGUYEN HUYNH THAO THY; RAJESH NITHYANANDAM

    2016-01-01

    Bioethanol process using cellulosic materials have been emerging an interesting field with a high potential of replacing petroleum-based fuel, as a future alternative. This work emphasised on improvement of enzymatic hydrolysis of alkaline NaOH-pretreated cellulose by applying an ultrafiltration membrane 10 kDa cutoff in order to minimise sugar inhibition on enzymes, reuse enzyme in hydrolysis and recover sugar for the subsequent fermentation. An improvement in the methodology of the enzymati...

  10. Observing cellulose biosynthesis and membrane translocation in crystallo.

    Science.gov (United States)

    Morgan, Jacob L W; McNamara, Joshua T; Fischer, Michael; Rich, Jamie; Chen, Hong-Ming; Withers, Stephen G; Zimmer, Jochen

    2016-03-17

    Many biopolymers, including polysaccharides, must be translocated across at least one membrane to reach their site of biological function. Cellulose is a linear glucose polymer synthesized and secreted by a membrane-integrated cellulose synthase. Here, in crystallo enzymology with the catalytically active bacterial cellulose synthase BcsA-BcsB complex reveals structural snapshots of a complete cellulose biosynthesis cycle, from substrate binding to polymer translocation. Substrate- and product-bound structures of BcsA provide the basis for substrate recognition and demonstrate the stepwise elongation of cellulose. Furthermore, the structural snapshots show that BcsA translocates cellulose via a ratcheting mechanism involving a 'finger helix' that contacts the polymer's terminal glucose. Cooperating with BcsA's gating loop, the finger helix moves 'up' and 'down' in response to substrate binding and polymer elongation, respectively, thereby pushing the elongated polymer into BcsA's transmembrane channel. This mechanism is validated experimentally by tethering BcsA's finger helix, which inhibits polymer translocation but not elongation. PMID:26958837

  11. Microwave-assisted preparation of cellulose membranes and their properties

    Czech Academy of Sciences Publication Activity Database

    Lenfeld, Jiří; Beneš, Milan J.; Hradil, Jiří; Šlouf, Miroslav; Plichta, Zdeněk

    Loughborough : Loughborough University, 2003 - (Binner, J.), s. 445-448 [International Conference on Microwave and High Frequency Heating /9./. Loughborough (GB), 01.09.2003-05.09.2003] R&D Projects: GA ČR GA203/02/1244 Institutional research plan: CEZ:AV0Z4050913 Keywords : cellulose membranes * viscose Subject RIV: CD - Macromolecular Chemistry

  12. High-speed water sterilization using silver-containing cellulose membranes

    International Nuclear Information System (INIS)

    The removal of bacteria and other pathogenic micro-organisms from drinking water is usually carried out by boiling; however, when this is not a feasible option, a combination of treatment based on filtration and disinfection is recommended. In this work, we produced cellulose filters grafted with silver nanoparticles (AgNPs) and silver nanowires (AgNWs) by covalent attachment of separately prepared Ag nanostructures on thiol- and amine-modified commercially available cellulosic filters. Results obtained from scanning electron microscopy (SEM), scanning transmission electron microscopy (STEM), and energy-dispersive X-ray spectroscopy (EDS) all revealed that such modified cellulose membranes contained large amounts of homogeneously dispersed AgNPs, whereas X-ray photoelectron spectroscopy (XPS) analysis demonstrated that the aforementioned nanostructures were immobilized on the membrane with a strong and stable covalent bond between the thiol or amine groups and the surface of the Ag nanofillers. This durable and robust covalent attachment facilitated outstanding suppression of the uncontrolled release of the nanostructures from the membranes, even under strong ultrasonication. Those membranes also demonstrated high permeance and antimicrobial activity in excess of 99.9% growth inhibition against Escherichia coli, which was used as a model of gram-negative coliform bacteria. Bacteria percolated throughout the tortuous silver-loaded filters, thus increasing the chances of contact between the Ag nanostructures (wires or nanoparticles) and the passing bacteria. Thus, we anticipate that these filters, with their high antibacterial activity and robustness, can be produced in a cost-effective manner and that they would be capable of producing affordable, clean, and safe drinking water in a short period of time without producing an uncontrolled silver release into the percolated water. (paper)

  13. High-speed water sterilization using silver-containing cellulose membranes

    Science.gov (United States)

    Sinclair, Terica; Zieba, Maciej; Irusta, Silvia; Sebastián, Víctor; Arruebo, Manuel

    2014-08-01

    The removal of bacteria and other pathogenic micro-organisms from drinking water is usually carried out by boiling; however, when this is not a feasible option, a combination of treatment based on filtration and disinfection is recommended. In this work, we produced cellulose filters grafted with silver nanoparticles (AgNPs) and silver nanowires (AgNWs) by covalent attachment of separately prepared Ag nanostructures on thiol- and amine-modified commercially available cellulosic filters. Results obtained from scanning electron microscopy (SEM), scanning transmission electron microscopy (STEM), and energy-dispersive X-ray spectroscopy (EDS) all revealed that such modified cellulose membranes contained large amounts of homogeneously dispersed AgNPs, whereas X-ray photoelectron spectroscopy (XPS) analysis demonstrated that the aforementioned nanostructures were immobilized on the membrane with a strong and stable covalent bond between the thiol or amine groups and the surface of the Ag nanofillers. This durable and robust covalent attachment facilitated outstanding suppression of the uncontrolled release of the nanostructures from the membranes, even under strong ultrasonication. Those membranes also demonstrated high permeance and antimicrobial activity in excess of 99.9% growth inhibition against Escherichia coli, which was used as a model of gram-negative coliform bacteria. Bacteria percolated throughout the tortuous silver-loaded filters, thus increasing the chances of contact between the Ag nanostructures (wires or nanoparticles) and the passing bacteria. Thus, we anticipate that these filters, with their high antibacterial activity and robustness, can be produced in a cost-effective manner and that they would be capable of producing affordable, clean, and safe drinking water in a short period of time without producing an uncontrolled silver release into the percolated water.

  14. Cellulose-Derived Supercapacitors from the Carbonisation of Filter Paper.

    Science.gov (United States)

    Jiang, Luyun; Nelson, Geoffrey W; Kim, Heeyeon; Sim, I N; Han, Seong Ok; Foord, John S

    2015-10-01

    Advanced carbon materials are important for the next-generation of energy storage apparatus, such as electrochemical capacitors. Here, the physical and electrochemical properties of carbonised filter paper (FP) were investigated. FP is comprised of pure cellulose and is a standardised material. After carbonisation at temperatures ranging from 600 to 1700 °C, FP was contaminant-free, containing only carbon and some oxygenated species, and its primary fibre structure was retained (diameter ≈20-40 μm). The observed enhancement in conductivity of the carbonised FP was correlated with the carbonisation temperature. Electrochemical capacitance in the range of ≈1.8-117 F g(-1) was achieved, with FP carbonised at 1500 °C showing the best performance. This high capacitance was stable with >87 % retained after 3000 charge-discharge cycles. These results show that carbonised FP, without the addition of composite materials, exhibits good supercapacitance performance, which competes well with existing electrodes made of carbon-based materials. Furthermore, given the lower cost and renewable source, cellulose-based materials are the more eco-friendly option for energy storage applications. PMID:26491636

  15. Electrically conductive bacterial cellulose composite membranes produced by the incorporation of graphite nanoplatelets in pristine bacterial cellulose membranes

    Directory of Open Access Journals (Sweden)

    T. Zhou

    2013-09-01

    Full Text Available Graphite nanoplatelets (GNPs were utilized to improve the electrical conductivity of pristine bacterial cellulose (BC membranes. By physical and chemical methods, flake-shaped GNPs, weaving through the surface layer of web-like cellulose nanofibrils, were indeed fixed or trapped by the adjacent nanofibrils in the BC surface network, for comparison, rod-shaped multi-walled carbon nanotubes (MWCNTs were homogeneously inserted into BC membrane through the pore structures and tunnels within the BC membrane. Strong physical and chemical interaction exists between the BC nanofibrils and the particles of GNP or MWCNT even after 15 h sonication. BC membrane with 8.7 wt% incorporated GNPs reached the maximum electrical conductivity of 4.5 S/cm, while 13.9 wt% MWCNT/BC composite membrane achieved the maximum electrical conductivity of 1.2 S/cm. Compared with one dimensional (1-D MWCNTs, as long as GNPs inserted into BC membranes, the 2-D reinforcement of GNPs was proven to be more effective in improving the electrical conductivity of BC membranes thus not only break the bottleneck of further improvement of the electrical conductivity of BC-based composite membranes but also broaden the applications of BC and GNPs.

  16. Outer Membrane Proteins of Fibrobacter succinogenes with Potential Roles in Adhesion to Cellulose and in Cellulose Digestion▿

    OpenAIRE

    Jun, Hyun-Sik; Qi, Meng; Gong, Joshua; Egbosimba, Emmanuel E.; Forsberg, Cecil W.

    2007-01-01

    Comparative analysis of binding of intact glucose-grown Fibrobacter succinogenes strain S85 cells and adhesion-defective mutants AD1 and AD4 to crystalline and acid-swollen (amorphous) cellulose showed that strain S85 bound efficiently to both forms of cellulose while mutant Ad1 bound to acid-swollen cellulose, but not to crystalline cellulose, and mutant Ad4 did not bind to either. One- and two-dimensional electrophoresis (2-DE) of outer membrane cellulose binding proteins and of outer membr...

  17. Bacterial cellulose and bacterial cellulose-vaccarin membranes for wound healing.

    Science.gov (United States)

    Qiu, Yuyu; Qiu, Liying; Cui, Jing; Wei, Qufu

    2016-02-01

    Bacterial cellulose (BC) and bacterial cellulose-vaccarin (BC-Vac) membranes were successfully produced in large scale. BC was synthesized by Gluconacetobacter xylinum. BC-Vac membranes were prepared by immersing BC in vaccarin solution. The surface morphologies of BC and BC-Vac membranes were examined by a scanning electron microscope (SEM) and an atomic force microscopy (AFM). The images showed that BC-Vac exhibited the characteristic 3D nanofibrillar network of BC matrix but there was adhesion between fibers. The mechanical properties of BC and BC-Vac membranes were evaluated and the results indicated that the adding of drug vaccarin into the BC membranes increased the malleability indicated by the increment in elongation at break compared with BC. Fourier transform infrared spectroscopy (FTIR) analysis was conducted to confirm the incorporation of vaccarin in BC-Vac and investigate the hydroxyl interactions between BC and drug vaccarin. Cell viability and cell attachment studies demonstrated that BC and BC-Vac membranes had no cytotoxicity and could be a good carrier for cell growth. The wound healing performance was examined in vivo by rat skin models. Histological observations revealed that wounds treated with BC-Vac epithelialized and regenerated faster than treated with BC. Therefore, BC-Vac was considered as a potential candidate for wound dressing materials. PMID:26652377

  18. Preparation of tungsten filters and membranes

    Czech Academy of Sciences Publication Activity Database

    Brožek, Vlastimil; Matějíček, Jiří; Neufuss, Karel

    Lillehammer - Norway : Ed.Bredesen & Raeder, SINTEF, Norway, 2006, s. 637-640. ISBN 82-14-04026-5. [International Conference on Inorganic Membranes 9ICIM /9th./. Lillehammer, Norway (NO), 25.06.2006-29.06.2006] R&D Projects: GA ČR(CZ) GA104/05/0540 Institutional research plan: CEZ:AV0Z20430508 Keywords : tungsten * tungsten carbide * metallic membranes * metallic filters Subject RIV: JK - Corrosion ; Surface Treatment of Materials

  19. Antimicrobial Bacterial Cellulose-Silver Nanoparticles Composite Membranes

    Directory of Open Access Journals (Sweden)

    Hernane S. Barud

    2011-01-01

    Full Text Available Antimicrobial bacterial cellulose-silver nanoparticles composite membranes have been obtained by “in situ” preparation of Ag nanoparticles from hydrolytic decomposition of silver nitrate solution using triethanolamine as reducing and complexing agent. The formation of silver nanoparticles was evidenced by the X-ray diffraction, scanning electron microscopy (SEM, transmission electron microscopy (TEM, and absorption in the UV-Visible (350 nm to 600 nm. Thermal and mechanical properties together with swelling behavior for water were considered. TEA concentration was observed to be important in order to obtain only Ag particles and not a mixture of silver oxides. It was also observed to control particle size and amount of silver contents in bacterial cellulose. The composite membranes exhibited strong antimicrobial activity against Gram-negative and Gram-positive bacteria.

  20. Antimicrobial Bacterial Cellulose-Silver Nanoparticles Composite Membranes

    OpenAIRE

    Barud, Hernane S.; Thaís Regiani; Rodrigo F. C. Marques; Wilton R. Lustri; Younes Messaddeq; Ribeiro, Sidney J.L.

    2011-01-01

    Antimicrobial bacterial cellulose-silver nanoparticles composite membranes have been obtained by “in situ” preparation of Ag nanoparticles from hydrolytic decomposition of silver nitrate solution using triethanolamine as reducing and complexing agent. The formation of silver nanoparticles was evidenced by the X-ray diffraction, scanning electron microscopy (SEM), transmission electron microscopy (TEM), and absorption in the UV-Visible (350 nm to 600 nm). Thermal and mechanical properties toge...

  1. Laboratory experiments on membrane filter sampling of airborne mycotoxins produced by Stachybotrys atra corda

    Science.gov (United States)

    Pasanen, A.-L.; Nikulin, M.; Tuomainen, M.; Berg, S.; Parikka, P.; Hintikka, E.-L.

    A membrane filter method for sampling of airborne stachybotrystoxins was studied in the laboratory. Toxigenic strains of Stachybotrys atra on wallpaper, grain, hay and straw were used as toxin sources in the experiments. Air samples were collected on cellulose nitrate and polycarbonate membrane filters at air flow rates of 10-20 ℓ min -1. After the filter sampling, the air was passed through methanol. The results showed that stachybotrystoxins (trichothecenes) were concentrated in airborne fungal propagules, and thus can be collected on filters. Polycarbonate filters with a pore size of 0.2 μm collected the highest percentage of toxic samples. The laboratory experiments indicated that polycarbonate filter sampling for the collection of airborne mycotoxins is a promising method for extension to field measurements.

  2. Cellulose as Sustainable Materials for Separation Membranes

    Science.gov (United States)

    Chu, Benjamin

    2013-03-01

    Polysaccharides, while complex, form one of the most abundant sustainable resources on earth. We want to take advantage of fundamental advances in materials understanding across length and time scales to investigate the interrelationships between structure, morphology, processing, properties, performance, and cost to meet the specific challenges arising from separation membranes for water purification. Non-woven fiber mats have unique properties, such as interconnected pores, a very large surface-to-volume ratio, and a high capacity for surface modifications. The breakthrough concept of combining fibrous mats composed of different fiber diameters for fabricating scaffolds as a unique platform for water purification is presented. Further, we take advantage of recent advances in chemical modifications, structural studies using synchrotron X-rays, and physical scale-up transformations to drastically improve filtration membrane development. Support of this work by the NSF, ONR, NIH and Stony Brook Univ. is gratefully acknowledged. The Chu/Hsiao group on water purification includes Profs. B.S.Hsiao and C.Burger, Drs. H-Y.Ma, D-F.Fang, R.Wang, and grad students: X.Wang, Z. Wang, Y.Su, R. Yang

  3. Comparison of concentrations of ions sampled on cellulose and teflon filters

    OpenAIRE

    Kořínková, Alena

    2012-01-01

    Determination of chloride, fluoride, nitrate, sulfate, oxalate and ammonium bounded to aerosol by sampling on cellulose filters is influenced by positive and negative interferences of gaseous pollutants. Interferences of gaseous pollutants during sampling of aerosols on teflon filters were eliminated by including of annular diffusion denuder in front of the filter.

  4. Cellulosic Sorption Filter Materials with Surface Flocculation Activity—A Hopeful Anticipation of Water Purification

    OpenAIRE

    Miloslav Milichovský; Břetislav Češek; Michaela Filipi; Jan Gojný

    2014-01-01

    A filter media was developed comprising ionic activated cellulosic material with enormous sorption activity to ions-active dissolved and colloidal substances in aqueous systems evoking so-called surface flocculation and a filling material having a filter effect. The dilemma of the art of low sorption efficiency and high flow rate of filtrated aqueous dispersions without sacrificing its separation efficiency of fines has been solved by use of activated cellulosic materia...

  5. The effect of bacterial cellulose membrane compared with collagen membrane on guided bone regeneration

    Science.gov (United States)

    Lim, Youn-Mook; Jeong, Sung In; An, Sung-Jun; Kang, Seong-Soo

    2015-01-01

    PURPOSE This study was to evaluate the effects of bacterial cellulose (BC) membranes as a barrier membrane on guided bone regeneration (GBR) in comparison with those of the resorbable collagen membranes. MATERIALS AND METHODS BC membranes were fabricated using biomimetic technology. Surface properties were analyzed, Mechanical properties were measured, in vitro cell proliferation test were performed with NIH3T3 cells and in vivo study were performed with rat calvarial defect and histomorphometric analysis was done. The Mann-Whitney U test and the Wilcoxon signed rank test was used (α<.05). RESULTS BC membrane showed significantly higher mechanical properties such as wet tensile strength than collagen membrane and represented a three-dimensional multilayered structure cross-linked by nano-fibers with 60 % porosity. In vitro study, cell adhesion and proliferation were observed on BC membrane. However, morphology of the cells was found to be less differentiated, and the cell proliferation rate was lower than those of the cells on collagen membrane. In vivo study, the grafted BC membrane did not induce inflammatory response, and maintained adequate space for bone regeneration. An amount of new bone formation in defect region loaded with BC membrane was significantly similar to that of collagen membrane application. CONCLUSION BC membrane has potential to be used as a barrier membrane, and efficacy of the membrane on GBR is comparable to that of collagen membrane. PMID:26816579

  6. FRACTIONATION OF HYDROLYZED MICROCRYSTALLINE CELLULOSE BY ULTRAFILTRATION MEMBRANE

    Directory of Open Access Journals (Sweden)

    NGUYEN HUYNH THAO THY

    2016-01-01

    Full Text Available Bioethanol process using cellulosic materials have been emerging an interesting field with a high potential of replacing petroleum-based fuel, as a future alternative. This work emphasised on improvement of enzymatic hydrolysis of alkaline NaOH-pretreated cellulose by applying an ultrafiltration membrane 10 kDa cutoff in order to minimise sugar inhibition on enzymes, reuse enzyme in hydrolysis and recover sugar for the subsequent fermentation. An improvement in the methodology of the enzymatic hydrolysis with ultrafiltration was made that the membrane was installed at the end of a tube connecting with a peristaltic pump to continuously remove glucose from hydrolysis reaction hence sugar was unable to inhibit enzyme activity and enzyme was retained inside the reactor for the reusing purpose. The combination of NaOH 1M alkaline pretreatment, enzymatic hydrolysis of cellulose with the optimum 3% enzyme dosage, ultrafiltration 10 kDa cutoff was evaluated to obtain the highest sugar concentration at 9 mg/ml after 6 hour hydrolysis. In comparison between hydrolysis with ultrafiltration and hydrolysis without ultrafiltration, the sugar concentration in hydrolysis with ultrafiltration was very much higher than that in hydrolysis without ultrafiltration in all enzyme dosages (1.5%, 3%, 6%. The hydrolysis with filtration produced a time profile in six hours with continuously significant increase in the sugar concentration. Only a small reduction initially for 1.5% dosage and no reduction in sugar concentration in 3% and 6% dosages. Hence the effect of product inhibition in hydrolysis was minimised as a result. In addition, a direct relationship between sugar concentration inside hydrolysis reactor, enzyme dosage and rate of sugar removal was observed during the hydrolysis process. Higher enzyme dosage in hydrolysis required a higher rate of sugar removal sufficiently to avoid inhibition in hydrolysis reaction.

  7. Improved Fixation of Cellulose-Acetate Reverse-Osmosis Membrane for Scanning Electron Microscopy

    OpenAIRE

    Kutz, S. M.; Bentley, D L; Sinclair, N A

    1985-01-01

    Fixation of cellulose-acetate membranes with either glutaraldehyde-osmium tetroxide or glutaraldehyde-ruthenium tetroxide resulted in extensive electron beam damage. Beam damage was eliminated and the bacterial surface structure was preserved, however, when cellulose-acetate membranes were fixed with glutaraldehyderuthenium tetroxide and treated successively with thiocarbohydrazide and osmium tetroxide.

  8. Evaluation of the permeability of modified cellulose acetate propionate membranes for use in biosensors based on hydrogen peroxide detection

    OpenAIRE

    Guiomar, A. Jorge; Stephen D. Evans; Guthrie, James

    2001-01-01

    Phase inversion cellulose acetate propionate membranes showed lowpermeability to hydrogen peroxide aqueous solutions. Their permeability wasincreased by alkaline hydrolysis of the ester linking units. However, thepermeability remained lower than that of an unsubstituted cellulose membrane.The inclusion of hydroxypropyl cellulose in the membrane formulation, followedby an alkaline hydrolysis step, increased permeability to hydrogen peroxideaqueous solutions to 29% of that of an unsubstituted c...

  9. Deposition of Aerosol Particles in Electrically Charged Membrane Filters

    International Nuclear Information System (INIS)

    A theory for the influence of electric charge on particle deposition on the surface of charged filters has been developed. It has been tested experimentally on ordinary membrane filters and Nuclepore filters of 8 μm pore size, with a bipolar monodisperse test aerosol of 1 μm particle diameter, and at a filter charge up to 20 μC/m2. Agreement with theory was obtained for the Coulomb force between filter and particle for both kinds of filters. The image force between charged filter and neutral particles did not result in the predicted deposition in the ordinary membrane filter, probably due to lacking correspondence between the filter model employed for the theory, and the real filter. For the Nuclepore filter a satisfactory agreement with theory was obtained, also at image interaction

  10. Membrane filter contact technique for bacteriological sampling of moist surfaces.

    OpenAIRE

    Craythorn, J M; Barbour, A G; Matsen, J M; Britt, M R; Garibaldi, R A

    1980-01-01

    We used a membrane filter contact technique to pick up and grow bacteria from artificially contaminated surfaces. We were able to recover individual colony-forming units (CFU) of Staphylococcus aureus from a moist agar surface more efficiently with 3- and 5- micron membrane filters than with Rodac plates, velvet pads, velveteen pads, or smaller-pore membrane filters. The effective transfer of bacteria with the 3- and 5-micron membrane filters was 0.96 +/- 0.04 (standard error of the mean) and...

  11. Crosslinked cellulose thin film composite nanofiltration membranes with zero salt rejection

    KAUST Repository

    Puspasari, Tiara

    2015-05-14

    We report a new synthetic route of fabricating regenerated cellulose nanofiltration membranes. The membranes are composite membranes with a thin selective layer of cellulose, which was prepared by regeneration of trimethylsilyl cellulose (a hydrophobic cellulose derivative) film followed by crosslinking. Filtration experiments using mixtures of sugar and sodium chloride showed that solutes above 300 Da were highly rejected whereas practically no rejection was observed for NaCl. This is a big advantage for a complete desalination as the existing commercial nanofiltration membranes typically exhibit NaCl rejection in the range of 30–60%. Membranes with zero NaCl rejection are required for recovery and purification applications in food, chemical and pharmaceutical industry.

  12. Comparison of concentration of ions in PM1 aerosol sampled on nitrate cellulose and teflon filters

    Czech Academy of Sciences Publication Activity Database

    Kořínková, Alena; Mikuška, Pavel; Večeřa, Zbyněk

    Aligarh: Aligarh Muslim University, 2013. s. 73-73. ISBN N. [International Conferenceon Chemistry: Frontiers and challenges. 02.03.2013-03.03.2013, Aligarh] Institutional support: RVO:68081715 Keywords : aerosol * ions * nitrate cellulose and teflon filter Subject RIV: CB - Analytical Chemistry, Separation

  13. Development of wet-dry reversible reverse osmosis membrane with high performance from cellulose acetate and cellulose triactate blend

    NARCIS (Netherlands)

    Vasarhelyi, K.; Ronner, J.A.; Mulder, M.H.V.; Smolders, C.A.

    1987-01-01

    Wet-dry reversible membrane were prepared bt a two-step coagulation procedure. A cast film containing a blend of cellulose triacetate as polymers, dioxane and acetone as solvents and maleic acid and methanol as additives was immersed consecutively in two aqueous coagulation baths, the first bath bei

  14. Arabidopsis cortical microtubules position cellulose synthase delivery to the plasma membrane and interact with cellulose synthase trafficking compartments.

    NARCIS (Netherlands)

    Gutierrez, R.; Lindeboom, J.J.; Paredez, A.R.; Emons, A.M.C.; Ehrhardt, D.W.

    2009-01-01

    Plant cell morphogenesis relies on the organization and function of two polymer arrays separated by the plasma membrane: the cortical microtubule cytoskeleton and cellulose microfibrils in the cell wall. Studies using in vivo markers confirmed that one function of the cortical microtubule array is t

  15. Primary study of ethyl cellulose nanofiber for oxygen-enrichment membrane

    Directory of Open Access Journals (Sweden)

    Shen Jing

    2016-01-01

    Full Text Available Ethyl cellulose is widely used for oxygen-enrichment membrane, however, its nanofiber membrane was rarely developed though it behaves more excellent performance. This paper gives a preliminary study to produce oxygen-enrichment membrane by bubbfil spinning.

  16. Chain scission and anti fungal effect of electron beam on cellulose membrane

    International Nuclear Information System (INIS)

    Two types of bacterial cellulose (BC) membranes were produced under a modified H and S medium using sucrose as a carbon source, with (CCB) and without (SHB) coconut juice supplement. Both membranes showed similar crystallinity of 69.24 and 71.55%. After being irradiated with E-beams under oxygen limited and ambient condition, the results from water contact angle showed that only the irradiated membrane CCB was increased from 30 to 40 degrees, and irradiation under oxygen ambient condition provided the greatest value. Comparing with the control membranes, smaller water flux was the cases after electron beam irradiation which indicated a reduction of membrane pore area. However, the results from molecular weight cut off (MWCO) revealed that chain scission was greater for membrane SHB and its cut off was increased from 28,000 Da to more than 35,000 Da. FTIR analysis revealed some changes in membrane functional groups, corresponding with the above results. These changes initiated new property of cellulose membranes, an anti-fungal food wrap. - Highlights: ► Electron beam irradiation increased membrane hydrophobicity and molecular weight cut off. ► The irradiation caused chain scissoring and anti fungal property of cellulose membrane. ► FT-IR studies revealed changes in functional groups causing a decrease in membrane moisture. ► Anti fungal test of cellulose membrane showed the same shelf life as polyethylene sheet.

  17. Ultrathin cellulose nanosheet membranes for superfast separation of oil-in-water nanoemulsions

    Science.gov (United States)

    Zhou, Ke; Zhang, Qiu Gen; Li, Hong Mei; Guo, Nan Nan; Zhu, Ai Mei; Liu, Qing Lin

    2014-08-01

    Oily wastewater is generated in diverse industrial processes, and its treatment has become crucial due to increasing environmental concerns. Herein, novel ultrathin nanoporous membranes of cellulose nanosheets have been fabricated for separation of oil-in-water nanoemulsions. The fabrication approach is facile and environmentally friendly, in which cellulose nanosheets are prepared by freeze-extraction of a very dilute cellulose solution. The as-prepared membranes have a cellulose nanosheet layer with a cut-off of 10-12 nm and a controllable thickness of 80-220 nm. They allow ultrafast water permeation and exhibit excellent size-selective separation properties. A 112 nm-thick membrane has a water flux of 1620 l m-2 h-1 bar-1 and a ferritin rejection of 92.5%. These membranes have been applied to remove oil from its aqueous nanoemulsions successfully, and they show an ultrafast and effective separation of oil-in-water nanoemulsions. The newly developed ultrathin cellulose membranes have a wide application in oily wastewater treatment, separation and purification of nanomaterials.Oily wastewater is generated in diverse industrial processes, and its treatment has become crucial due to increasing environmental concerns. Herein, novel ultrathin nanoporous membranes of cellulose nanosheets have been fabricated for separation of oil-in-water nanoemulsions. The fabrication approach is facile and environmentally friendly, in which cellulose nanosheets are prepared by freeze-extraction of a very dilute cellulose solution. The as-prepared membranes have a cellulose nanosheet layer with a cut-off of 10-12 nm and a controllable thickness of 80-220 nm. They allow ultrafast water permeation and exhibit excellent size-selective separation properties. A 112 nm-thick membrane has a water flux of 1620 l m-2 h-1 bar-1 and a ferritin rejection of 92.5%. These membranes have been applied to remove oil from its aqueous nanoemulsions successfully, and they show an ultrafast and effective

  18. Treatment of tympanic membrane perforation using bacterial cellulose: a randomized controlled trial

    OpenAIRE

    Fábio Coelho Alves Silveira; Flávia Cristina Morone Pinto; Sílvio da Silva Caldas Neto; Mariana de Carvalho Leal; Jéssica Cesário; José Lamartine de Andrade Aguiar

    2016-01-01

    ABSTRACT INTRODUCTION: Promising treatments for tympanic membrane perforation closure have been studied. Therapies derived from tissue engineering probably eliminate the need for conventional surgery. Bacterial cellulose is presented as an alternative that is safe, biocompatible, and has low toxicity. OBJECTIVES: To investigate the effect on healing of direct application of a bacterial cellulose graft on the tympanic membrane compared to the conventional approach with autologous fascia. ME...

  19. Surface modification of cellulose acetate membrane using thermal annealing to enhance produced water treatment

    Energy Technology Data Exchange (ETDEWEB)

    Kusworo, T. D., E-mail: tdkusworo@che.undip.ac.id; Aryanti, N., E-mail: nita.aryanti@gmail.com; Firdaus, M. M. H.; Sukmawati, H. [Chemical Engineering, Faculty of Engineering, Diponegoro University Prof. Soedarto Street, Tembalang, Semarang, 50239, Phone/Fax : (024)7460058 (Indonesia)

    2015-12-29

    This study is performed primarily to investigate the effect of surface modification of cellulose acetate using thermal annealing on the enhancement of membrane performance for produced water treatment. In this study, Cellulose Acetate membranes were casted using dry/wet phase inversion technique. The effect of additive and post-treatment using thermal annealing on the membrane surface were examined for produced water treatment. Therma annealing was subjected to membrane surface at 60 and 70 °C for 5, 10 and 15 second, respectively. Membrane characterizations were done using membrane flux and rejection with produced water as a feed, Scanning Electron Microscopy (SEM) and Fourier Transform Infra Red (FTIR) analysis. Experimental results showed that asymmetric cellulose acetate membrane can be made by dry/wet phase inversion technique. The results from the Scanning Electron Microscopy (FESEM) analysis was also confirmed that polyethylene glycol as additivie in dope solution and thermal annealing was affected the morphology and membrane performance for produced water treatment, respectively. Scanning electron microscopy micrographs showed that the selective layer and the substructure of membrane became denser and more compact after the thermal annealing processes. Therefore, membrane rejection was significantly increased while the flux was slighty decreased, respectively. The best membrane performance is obtained on the composition of 18 wt % cellulose acetate, poly ethylene glycol 5 wt% with thermal annealing at 70° C for 15 second.

  20. Surface modification of cellulose acetate membrane using thermal annealing to enhance produced water treatment

    Science.gov (United States)

    Kusworo, T. D.; Aryanti, N.; Firdaus, M. M. H.; Sukmawati, H.

    2015-12-01

    This study is performed primarily to investigate the effect of surface modification of cellulose acetate using thermal annealing on the enhancement of membrane performance for produced water treatment. In this study, Cellulose Acetate membranes were casted using dry/wet phase inversion technique. The effect of additive and post-treatment using thermal annealing on the membrane surface were examined for produced water treatment. Therma annealing was subjected to membrane surface at 60 and 70 °C for 5, 10 and 15 second, respectively. Membrane characterizations were done using membrane flux and rejection with produced water as a feed, Scanning Electron Microscopy (SEM) and Fourier Transform Infra Red (FTIR) analysis. Experimental results showed that asymmetric cellulose acetate membrane can be made by dry/wet phase inversion technique. The results from the Scanning Electron Microscopy (FESEM) analysis was also confirmed that polyethylene glycol as additivie in dope solution and thermal annealing was affected the morphology and membrane performance for produced water treatment, respectively. Scanning electron microscopy micrographs showed that the selective layer and the substructure of membrane became denser and more compact after the thermal annealing processes. Therefore, membrane rejection was significantly increased while the flux was slighty decreased, respectively. The best membrane performance is obtained on the composition of 18 wt % cellulose acetate, poly ethylene glycol 5 wt% with thermal annealing at 70° C for 15 second.

  1. Surface modification of cellulose acetate membrane using thermal annealing to enhance produced water treatment

    International Nuclear Information System (INIS)

    This study is performed primarily to investigate the effect of surface modification of cellulose acetate using thermal annealing on the enhancement of membrane performance for produced water treatment. In this study, Cellulose Acetate membranes were casted using dry/wet phase inversion technique. The effect of additive and post-treatment using thermal annealing on the membrane surface were examined for produced water treatment. Therma annealing was subjected to membrane surface at 60 and 70 °C for 5, 10 and 15 second, respectively. Membrane characterizations were done using membrane flux and rejection with produced water as a feed, Scanning Electron Microscopy (SEM) and Fourier Transform Infra Red (FTIR) analysis. Experimental results showed that asymmetric cellulose acetate membrane can be made by dry/wet phase inversion technique. The results from the Scanning Electron Microscopy (FESEM) analysis was also confirmed that polyethylene glycol as additivie in dope solution and thermal annealing was affected the morphology and membrane performance for produced water treatment, respectively. Scanning electron microscopy micrographs showed that the selective layer and the substructure of membrane became denser and more compact after the thermal annealing processes. Therefore, membrane rejection was significantly increased while the flux was slighty decreased, respectively. The best membrane performance is obtained on the composition of 18 wt % cellulose acetate, poly ethylene glycol 5 wt% with thermal annealing at 70° C for 15 second

  2. Cellulose triacetate doped with ionic liquids for membrane gas separation

    Science.gov (United States)

    Lam, Benjamin Fatt Soon

    The doping of cellulose triacetate (CTA) with imidazolium based ionic liquids (ILs) is investigated in order to reduce the polymer crystallinity and enhance the affinity with CO2, thus increasing CO2 permeability and CO2/light gas selectivity. CTA membranes doped with [emim] BF4 or [emim] DCA were prepared, and the effect of the ILs loading on properties, such as crystallinity, density, degradation temperature, glass transition temperature, and gas transport properties, has been determined. In general, doping with IL reduces the crystallinity in CTA, increasing gas solubility, diffusivity and permeability. The ILs doping also increases CO 2/CH4 solubility selectivity and CO2/N2 permeability selectivity, due to the affinity of these ILs with CO2, instead of light gases such as CH4 and N2. This study provides a mechanistic understanding of interaction of ILs and CTA, and demonstrates an effective route in manipulating the morphology and gas transport properties of semi crystalline polymers by doping with ILs.

  3. Preparation and characterization of regenerated cellulose membranes from natural cotton fiber

    Directory of Open Access Journals (Sweden)

    Yanjuan CAO

    2015-06-01

    Full Text Available A series of organic solutions with different cellulose concentrations are prepared by dissolving natural cotton fibers in lithium chloride/dimethyl acetamide (LiCl/DMAC solvent system after the activation of cotton fibers. Under different coagulating bath, the regenerated cellulose membranes are formed in two kinds of coagulation baths, and two coating methods including high-speed spin technique (KW-4A spin coating machine and low-speed scraping (AFA-Ⅱ Film Applicator are selected in this paper. The macromolecular structure, mechanical properties, crystallinity, thermal stability and wetting property of the regenerated cellulose membrane are characterized by Scanning Electron Microscope(SEM, Fourier Transform Infrared Spectroscopy (FT-IR,X-ray diffraction (XRD, Thermogravimetric analysis (TG and contacting angle tester. The effects of mass fraction, coagulation bath type, membrane forming process on the regenerated membrane properties are investigated. Experimental results show that the performance of regenerated cellulose membrane is relatively excellent under the condition of using the KW-4A high-speed spin method, water coagulation bath, and when mass fraction of cellulose is 3.5%. The crystallinity of the regenerated cellulose membrane changes a lot compared with natural cotton fibers. The variation trend of thermal stability is similar with that of cotton fiber. But thermal stability is reduced to some degree, while the wetting ability is improved obviously.

  4. The effect of acid hydrolysis pretreatment on crystallinity and solubility of kenaf cellulose membrane

    International Nuclear Information System (INIS)

    Cellulose was extracted from kenaf core pulp (KCP) by series of bleaching steps in the sequence (DEED) where D and E are referred as acid and alkali treatment. The bleached kenaf pulp (BKCP) is then pretreated with acid hydrolysis at room temperature for 1 and 3 h respectively. The pretreated cellulose is dissolved in lithium hydroxide/urea (LiOH/urea) and cellulose solution produced was immersed in distilled water bath. BKCP without treatment was also conducted for comparison purpose. The effects of acid hydrolysis pretreatment on solubility and crystallinity are investigated. Higher solubility of cellulose solution is achieved for treated samples. Cellulose II formation and crystallinity index of the cellulose membrane were determined by X-ray diffraction (XRD)

  5. The effect of acid hydrolysis pretreatment on crystallinity and solubility of kenaf cellulose membrane

    Energy Technology Data Exchange (ETDEWEB)

    Saidi, Anis Syuhada Mohd; Zakaria, Sarani; Chia, Chin Hua; Jaafar, Sharifah Nabihah Syed; Padzil, Farah Nadia Mohammad [School of Applied Physics, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 UKM Bangi, Selangor (Malaysia)

    2015-09-25

    Cellulose was extracted from kenaf core pulp (KCP) by series of bleaching steps in the sequence (DEED) where D and E are referred as acid and alkali treatment. The bleached kenaf pulp (BKCP) is then pretreated with acid hydrolysis at room temperature for 1 and 3 h respectively. The pretreated cellulose is dissolved in lithium hydroxide/urea (LiOH/urea) and cellulose solution produced was immersed in distilled water bath. BKCP without treatment was also conducted for comparison purpose. The effects of acid hydrolysis pretreatment on solubility and crystallinity are investigated. Higher solubility of cellulose solution is achieved for treated samples. Cellulose II formation and crystallinity index of the cellulose membrane were determined by X-ray diffraction (XRD)

  6. The effect of acid hydrolysis pretreatment on crystallinity and solubility of kenaf cellulose membrane

    Science.gov (United States)

    Saidi, Anis Syuhada Mohd; Zakaria, Sarani; Chia, Chin Hua; Jaafar, Sharifah Nabihah Syed; Padzil, Farah Nadia Mohammad

    2015-09-01

    Cellulose was extracted from kenaf core pulp (KCP) by series of bleaching steps in the sequence (DEED) where D and E are referred as acid and alkali treatment. The bleached kenaf pulp (BKCP) is then pretreated with acid hydrolysis at room temperature for 1 and 3 h respectively. The pretreated cellulose is dissolved in lithium hydroxide/urea (LiOH/urea) and cellulose solution produced was immersed in distilled water bath. BKCP without treatment was also conducted for comparison purpose. The effects of acid hydrolysis pretreatment on solubility and crystallinity are investigated. Higher solubility of cellulose solution is achieved for treated samples. Cellulose II formation and crystallinity index of the cellulose membrane were determined by X-ray diffraction (XRD).

  7. Cellulose

    Science.gov (United States)

    Cellulose properties and structure are reviewed, with a primary focus on crystal structure and polymorphy. This focus highlights the conversion from cellulose I to cellulose II, which converts the molecules to being all parallel to each other in the crystal to being antiparallel. This has been co...

  8. Fabrication and characterization of micro-porous cellulose filters for indoor air quality control.

    Science.gov (United States)

    Yoon, Younghan; Kim, Sungyoun; Ahn, Kwang Ho; Ko, Kwang Baik; Kim, Kwang-Soo

    2016-03-01

    Micro-porous cellulose filters were fabricated from paper mulberry pulp, which has been used for thousands of years with Korean history. 'Han-ji' is the name of a traditional paper used widely in Korea in construction, textile, craftworks and many household items but before now it has not been used for filtration purpose. Seeking for the utilization of this abundant natural material, this study aims to develop a fabrication process for the traditional paper to be used as a filter for dust filtration, and evaluate the performance by lab-scale experiments. To create pores in the paper, cellulose pulp was pretreated using several methods such as TEMPO oxidation and enzyme hydrolysis, or freeze dried with an alcoholic freezing medium, t-butyl alcohol, instead of water. The filters were characterized and their dust removal performance was tested at a lab scale while also monitoring pressure loss. Chemical oxidation and enzymatic pretreatment were helpful in fabricating a homogeneous filter but would not remove fine-dust particles because of its loose, enlarged pores. The best removal efficiency was observed with filters that were not pretreated but in which water had been exchanged with t-butyl alcohol before freeze-drying. The filter attained a dust removal efficiency higher than 99% over the entire experimental period, with a pressure loss of less than 230 Pa, at a 6.67 (cm(3)/s)/cm(2) air-to-cloth ratio. PMID:26370434

  9. Cellulose acetate-based molecularly imprinted polymeric membrane for separation of vanillin and o-vanillin

    OpenAIRE

    Chunjing Zhang; Shian Zhong; Zhengpeng Yang

    2008-01-01

    Cellulose acetate-based molecularly imprinted polymeric membranes were prepared using vanillin as template molecule. The microscopic structure of the resultant polymeric membranes was characterized by SEM and FTIR spectroscopy, and the selective binding properties and separation capacity of the membranes for vanillin and o-vanillin were tested with binding experiments and separate experiments, respectively. The results showed that the vanillin-imprinted polymeric membranes displayed higher bi...

  10. Acid-fast microscopy on polycarbonate membrane filter sputum sediments.

    OpenAIRE

    Smithwick, R W; Stratigos, C B

    1981-01-01

    Polycarbonate membrane filters were used to concentrate 916 sputum specimens for detecting acid-fast bacilli by microscopic examination. These results were compared with those of smears prepared from centrifugates and direct smears of the same specimens. Culture isolation, the control procedure, demonstrated the presence of acid-fast bacilli in 76 specimens. The number of positive specimens detected by microscopy was 82 on polycarbonate membrane filter concentrates, with an 80.2% sensitivity;...

  11. Treatment of tympanic membrane perforation using bacterial cellulose: a randomized controlled trial

    Directory of Open Access Journals (Sweden)

    Fábio Coelho Alves Silveira

    2016-04-01

    Full Text Available ABSTRACT INTRODUCTION: Promising treatments for tympanic membrane perforation closure have been studied. Therapies derived from tissue engineering probably eliminate the need for conventional surgery. Bacterial cellulose is presented as an alternative that is safe, biocompatible, and has low toxicity. OBJECTIVES: To investigate the effect on healing of direct application of a bacterial cellulose graft on the tympanic membrane compared to the conventional approach with autologous fascia. METHODS: Randomized controlled trial. Forty patients with tympanic membrane perforations secondary to chronic otitis media were included, and were randomly assigned to an experimental group (20, treated with a bacterial cellulose graft (BC and control group (20, treated with autologous temporal fascia (fascia. We evaluated the surgical time, hospital stay, time of epithelialization and the rate of tympanic perforation closure. Hospital costs were compared. The statistical significance level accepted was established at p < 0.05. RESULTS: The closure of perforations was similar in both groups. The average operation time in the fascia group was 76.50 min versus 14.06 min bacterial cellulose in the group (p = 0.0001. The hospital cost by the Brazilian public health system was R$ 600.00 for the bacterial cellulose group, and R$ 7778.00 for the fascia group (p = 0.0001. CONCLUSION: Bacterial cellulose grafts promoted the closure of the tympanic membrane perforations, and were demonstrated to be innovative, effective, safe, minimally invasive, efficacious and to have a very low cost.

  12. Fabrication of flexible self-standing all-cellulose nanofibrous composite membranes for virus removal.

    Science.gov (United States)

    Huang, Weijuan; Wang, Yixiang; Chen, Chao; Law, John Lok Man; Houghton, Michael; Chen, Lingyun

    2016-06-01

    All-cellulose nanocomposite membranes with excellent performance were successfully fabricated as novel filtration system to remove nanoparticles and virus from aqueous medium. These membranes were composed of two combined layers: an electrospun cellulose nanofabric layer treated by hot-pressing to provide mechanical support and a coating of regenerated cellulose gel with tiny inter-connected pores as barrier. Hot-pressing did not affect the fiber shape of electrospun nanofabrics, but significantly improved their mechanical properties due to increased hydrogen bonds. The regenerated cellulose gel formed a porous coating that tightly attached to electrospun nanofabrics, and its pore size varied depending on cellulose source, solution concentration, and drying process. By assembling these two layers together, the nanocomposite membranes showed the notable retention of negatively charged 100nm latex beads (99.30%). Moreover, the electronegative nature of cellulose membranes imparted the rejection ratio of 100% and (98.68±0.71)% against positively charged 50nm latex beads and Hepatitis C Virus, respectively. PMID:27083338

  13. S-Acylation of the cellulose synthase complex is essential for its plasma membrane localization.

    Science.gov (United States)

    Kumar, Manoj; Wightman, Raymond; Atanassov, Ivan; Gupta, Anjali; Hurst, Charlotte H; Hemsley, Piers A; Turner, Simon

    2016-07-01

    Plant cellulose microfibrils are synthesized by a process that propels the cellulose synthase complex (CSC) through the plane of the plasma membrane. How interactions between membranes and the CSC are regulated is currently unknown. Here, we demonstrate that all catalytic subunits of the CSC, known as cellulose synthase A (CESA) proteins, are S-acylated. Analysis of Arabidopsis CESA7 reveals four cysteines in variable region 2 (VR2) and two cysteines at the carboxy terminus (CT) as S-acylation sites. Mutating both the VR2 and CT cysteines permits CSC assembly and trafficking to the Golgi but prevents localization to the plasma membrane. Estimates suggest that a single CSC contains more than 100 S-acyl groups, which greatly increase the hydrophobic nature of the CSC and likely influence its immediate membrane environment. PMID:27387950

  14. Back-washing method for hollow fiber membrane filter

    International Nuclear Information System (INIS)

    For processing condensates in a nuclear reactor, when the amount of the suspended matters contained in the condensates is increased upon filtering them through hollow fiber membrane, the hollow fiber membranes per se can no more be generated and have to be discarded. In view of the above, filtering operation is interrupted and air scrubbing is applied immediately for back-washing the hollow fiber membrane filters. Then, after filling water below a pipe plate and applying dome draining and dome pressurization, bumping is applied to the hollow fiber membranes. In this way, the scrubbing step is applied preferentially to the bumping step and a combination of the scrubbing and bumping step is repeated at least twice. This enables to conduct efficient back-washing and, accordingly, extend the life time of the hollow fiber membranes so that they can withstand long time use. (T.M.)

  15. Cellulose membrane as a biomaterial: from hydrolysis to depolymerization with electron beam.

    Science.gov (United States)

    Eo, Mi Young; Fan, Huan; Cho, Yun Ju; Kim, Soung Min; Lee, Suk Keun

    2016-01-01

    The cellulose membrane (CM) is a major component of plant cell walls and is both a chemically and mechanically stable synthetic polymer with many applications for use in tissue engineering. However, due to its dissolution difficulty, there are no known physiologically relevant or pharmaceutically clinical applications for this polymer. Thus, research is underway on controlled and adjusted forms of cellulose depolymerization. To advance the study of applying CM for tissue engineering, we have suggested new possibilities for electron beam (E-beam) treatment of CM. Treatment of CM with an E-beam can modify physical, chemical, molecular and biological properties, so it can be studied continuously to improve its usefulness and to enhance value. We review clinical applications of CM, cellulose binding domains, cellulose crosslinking proteins, conventional hydrolysis of cellulose, and depolymerization with radiation and focus our experiences with depolymerization of E-beam irradiated CM in this article. PMID:27418974

  16. PRODUCTION OF ANTIBACTERIAL FILTER PAPER FROM WOOD CELLULOSE

    Directory of Open Access Journals (Sweden)

    Reza Imani

    2011-02-01

    Full Text Available Paper has a visible market-share in hygiene products either in the form of personal hygiene or as food packaging. The designation “hygiene”, though it suggests cleanliness, does not imply antibacterial properties; rather it can be stated that hygiene products do not initiate microorganism growth. Antibacterial products could restrict propagation of pathogenic bacteria either by holding bacteria or by trapping and neutralizing them. Most research in this field has been conducted using textile fibers as a substrate, but the present work uses paper instead. The objective was to produce an antibacterial filter paper capable of trapping and neutralizing pathogenic microorganisms using wood fibers. To produce antibacterial paper, chitosan and nanosilver capped with PAA (polyacrylic acid were deposited on the fiber surface using a layer-by-layer technique. Samples for the tests were prepared from refined bleached softwood (RBSW kraft pulp. The deposition of antibacterial agents on fiber as well as paper were monitored using a zeta potential analyzer (ZPA, scanning electron microscopy (SEM, and Fourier transform infrared spectroscopy (FTIRS. The minimum requirement for deposition of the agents was a multilayer comprised of eight alternating layers. The deposition onto fiber or paper had no effect on tensile strength or the pore structure of the substrate.

  17. Celluloses filled ENR/PVC membranes for palm oil mill effluent (POME) treatment

    Science.gov (United States)

    Shamsuddin, Mohd Razali; Abdullah, Ibrahim; Othaman, Rizafizah

    2013-11-01

    Membranes from composite materials have been used especially in water treatment applications. In this paper the composite membranes of celluloses filled ENR/PVC were successfully prepared for POME treatment application. The preparation of the membrane involves solution blending, casting, phase inversion and drying methods. Two types of fillers, cellulose (Cell) and cellulose grafting polymethyl methacrylate (Cell-g-PMMA) were added into ENR/PVC matrix in various compositions (1, 5, 10, 15 and 20 wt%) to determine the effect of the filler to the performance of the membrane. The membranes were characterized by using FTIR and SEM. Membrane properties in terms of porosity and water flux were examined using mathematical calculation. FTIR spectrum shows the existence of stretching vibration from the functional group of ester carbonyl, -C=O at peak 1725 cm-1 that belongs to Cell-g-PMMA filler in ENR/PVC/Cell-g-PMMA membrane which makes the membranes slightly hydrophobic. SEM micrographs exhibit that pores were formed on both ENR/PVC/Cell and ENR/PVC/Cell-g-PMMA membranes. Water flux test indicates that ENR/PVC/Cell-20% was the highest because the addition of Cell increases the hydrophilicity of the membrane. In POME treatment, ENR/PVC/Cell-20% and ENR/PVC/Cell-g-PMMA-10% showed the highest decolorization.

  18. Influence of coagulation bath on morphology of cellulose membranes prepared by NMMO method

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    To control the morphology of cellulose membranes used for separation,they were prepared by the NMMO method using water,methanol,ethanol and their binary solution as coagulation baths.Morphologies of the surface and cross section of dry membranes were observed.The pore structure parameters of wet membranes were determined.By comparison,the process and mechanism of pore formation in dry membranes were suggested,and the relativity of cellulose crystal size to average pore diameter in wet membranes and their influences were discussed.The results show that the morphology of dry membranes is clearly varied with coagulation baths,while the porosity of wet membranes is almost constant.Porous structures can appear in the compact region of dry membranes due to swelling from water.These pores have a virtual effect on the average pore diameter of wet membranes.By changing the composition of coagulation baths,the microstructure of cellulose membranes in a dry or wet environment can be adjusted separately.

  19. Synthesis and characterization of polyurethane-cellulose acetate blend membrane for chromium (VI) removal.

    Science.gov (United States)

    Riaz, Tabinda; Ahmad, Adnan; Saleemi, Sidra; Adrees, Muhammad; Jamshed, Fahad; Hai, Abdul Moqeet; Jamil, Tahir

    2016-11-20

    Blended membranes of polyurethane and cellulose acetate were prepared, characterized and investigated for their performance. Various ratios of cellulose acetate were employed to prepare four different blend membranes. The characteristics of both pure and blend membranes were investigated and results were compared to distinguish their properties. Functional group analysis was carried out by attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) of pure and blend samples. Contact angle measurement and water content were evaluated to determine the membrane hydrophilicity. Moreover, the membrane morphology was studied by scanning electron microscopy (SEM). The membrane permeation properties and ability to reject chromium (VI) ions were tested at various pH and pressure by utilizing different salt concentrations. PMID:27561531

  20. Cellulose Acetate 398-10 Asymmetric Membrane Capsules for Osmotically Regulated Delivery of Acyclovir

    OpenAIRE

    Alka Sonkar; Anil Kumar; Kamla Pathak

    2016-01-01

    The study was aimed at developing cellulose acetate asymmetric membrane capsules (AMCs) of acyclovir for its controlled delivery at the absorption site. The AMCs were prepared by phase inversion technique using wet process. A 23 full factorial design assessed the effect of independent variables (level(s) of polymer, pore former, and osmogen) on the cumulative drug release from AMCs. The buoyant optimized formulation F7 (low level of cellulose acetate; high levels of both glycerol and sodium l...

  1. Bacterial Cellulose Membranes Used as Artificial Substitutes for Dural Defection in Rabbits

    OpenAIRE

    Chen Xu; Xia Ma; Shiwen Chen; Meifeng Tao; Lutao Yuan; Yao Jing

    2014-01-01

    To improve the efficacy and safety of dural repair in neurosurgical procedures, a new dural material derived from bacterial cellulose (BC) was evaluated in a rabbit model with dural defects. We prepared artificial dura mater using bacterial cellulose which was incubated and fermented from Acetobacter xylinum. The dural defects of the rabbit model were repaired with BC membranes. All surgeries were performed under sodium pentobarbital anesthesia, and all efforts were made to minimize suffering...

  2. Effect of electron beam irradiation on bacterial cellulose membranes used as transdermal drug delivery systems

    International Nuclear Information System (INIS)

    Ionizing radiation is an effective energetic source for polymer surfaces modification in order to obtain transdermal systems with different controlled release properties. In this work, gamma rays have been applied to induce changes in bacterial cellulose membranes. Permeation of drug (tetracycline) was theoretically and experimentally investigated starting from the effect of γ-irradiation on membranes permeability. Release and permeation of drug from irradiated and non-irradiated membranes have been performed using a diffusion cell

  3. Effect of electron beam irradiation on bacterial cellulose membranes used as transdermal drug delivery systems

    Science.gov (United States)

    Stoica-Guzun, Anicuta; Stroescu, Marta; Tache, Florin; Zaharescu, Traian; Grosu, Elena

    2007-12-01

    Ionizing radiation is an effective energetic source for polymer surfaces modification in order to obtain transdermal systems with different controlled release properties. In this work, gamma rays have been applied to induce changes in bacterial cellulose membranes. Permeation of drug (tetracycline) was theoretically and experimentally investigated starting from the effect of γ-irradiation on membranes permeability. Release and permeation of drug from irradiated and non-irradiated membranes have been performed using a diffusion cell.

  4. Effect of electron beam irradiation on bacterial cellulose membranes used as transdermal drug delivery systems

    Energy Technology Data Exchange (ETDEWEB)

    Stoica-Guzun, Anicuta [Department of Chemical Engineering, ' Politehnica' University Bucharest, 313 Splaiul Independentei, 060042 Bucharest (Romania)], E-mail: astoica@mt.pub.ro; Stroescu, Marta; Tache, Florin [Department of Chemical Engineering, ' Politehnica' University Bucharest, 313 Splaiul Independentei, 060042 Bucharest (Romania); Zaharescu, Traian [Advanced Research Institute for Electrical Engineering, 313 Splaiul Unirii, 030138 Bucharest (Romania)], E-mail: zaharescut@icpe-ca.ro; Grosu, Elena [Department of Chemical Engineering, ' Politehnica' University Bucharest, 313 Splaiul Independentei, 060042 Bucharest (Romania)

    2007-12-15

    Ionizing radiation is an effective energetic source for polymer surfaces modification in order to obtain transdermal systems with different controlled release properties. In this work, gamma rays have been applied to induce changes in bacterial cellulose membranes. Permeation of drug (tetracycline) was theoretically and experimentally investigated starting from the effect of {gamma}-irradiation on membranes permeability. Release and permeation of drug from irradiated and non-irradiated membranes have been performed using a diffusion cell.

  5. Effect of Gamma Irradiation on Microbial Cellulose Membrane For Application In Guided Bone Regeneration (GBR)

    International Nuclear Information System (INIS)

    The synthesis and effect of gamma irradiation on characteristics of microbial cellulose membrane have been evaluated. Microbial cellulose gel (nata de coco) was produce using bacteria Acetobacter xylinum incubated in bacterial growth medium containing coconut water as a micro nutrient source. Microbial cellulose membrane was prepared using mould compression at 120°C for 5 minutes. The membranes were irradiated using gamma rays with doses of 25 and 50 kGy respectively at dose rate of 10 kGy/h. Several parameters such as water absorption, surface morphology, thermal and mechanical properties of un-irradiated and irradiated membranes were analyzed. The results showed that optimum production of microbial cellulose by A. Xylinum is 10 to 12 days at incubation temperature of 30°C and pH 4. Chemically treatments of MC membrane by NaOH and NaOCl solution were effective to remove the bacteria contaminant, bacterial cells embedded in the polymer net and endotoxin which occurred during cellulose production as well as produced membrane with more white colour. Water absorption properties of MC membranes showed maximum value at immersion temperature of 25°C, 37°C and 50°C were 110, 137 and 140 %, respectively. Water absorption of MC membrane decreases by increasing irradiation dose. Microscopic photograph of MC membrane showed that the membrane was consisted of interconnected nano to micro porous structures with diameter ranging from 0.05 to 0.5 μm. Thermal properties of MC showed that decomposition temperature of un-irradiated and irradiated MC membrane at dose of 25 and 50 kGy were 328°C, 328°C and 295°C, respectively. Tensile strength of un-irradiated MC membrane in dry state was 102 MPa. Irradiation at 25 and 50 kGy reduced tensile strength to become 85 and 51 MPa respectively. The decrease of thermal property and mechanical strength of MC membrane by irradiation is due to decomposition of polymeric cellulose to the lower molecular weight. This degradation hopefully

  6. Preparation of membranes from cellulose obtained of sugarcane bagasse; Preparacao de membranas a partir de celulose obtida do bagaco de cana-de-acucar

    Energy Technology Data Exchange (ETDEWEB)

    Pereira, Paulo Henrique Fernandes; Cioffi, Maria Odila Hilario; Voorwald, Herman Jacobus Cornelis, E-mail: fernandes_eng@yahoo.com.b [UNESP, Guaratingueta, SP (Brazil). Fac. de Engenharia; Pinho, Maria Noberta de [Instituto Superior Tecnico de Lisboa (IST) (Portugal), Dept. de Engenharia; Silva, Maria Lucia Caetano Pinto da [Universidade de Sao Paulo (EEL/USP), Lorena, SP (Brazil). Escola de Engenharia

    2010-07-01

    In this work, cellulose obtained from sugarcane bagasse to produce both cellulose and acetylated cellulose to prepare asymmetric membranes. Membranes was procedure used a mixture of materials of DMAc/ LiCl systemic in different conditions. Cellulose and acetylated cellulose were characterized by thermogravimetric (TG), Xray diffraction (XRD) and scanning Electron Microscopy (SEM). Observed less stability thermal of acetylated cellulose when compared of cellulose. All membranes procedure were asymmetric, characterized by presence of a dense skin and porous support can be observed. SEM showed that the morphology of the superficial of membranes depends on the method preparation. (author)

  7. Characterization of cellulose membranes modified with luminescent silicon quantum dots nanoparticles.

    Science.gov (United States)

    Campos, B B; Gelde, L; Algarra, M; Esteves da Silva, J C G; Vázquez, M I; Benavente, J

    2016-10-20

    A highly hydrophilic planar membrane fabricated with regenerated cellulose (RC-4 membrane), a biocompatible polymer, was modified by inclusion of water-soluble silicon quantum dot nanoparticles (SiQDs). Both bare SiQDs and SiQDs coated with a PAMAM-OH dendrimer were employed in order to obtain luminescent and thermally stable membrane systems (RC-4/SiQDs and RC-4/SiQDs-PAMAM-OH membranes). Original and SiQDs-modified membranes were characterized by fluorescence spectroscopy (steady and confocal), derivative thermogravimetric analysis and impedance spectroscopy measurements. According to these results, both SiQDs-regenerated cellulose composite membranes present luminescent character as well as higher thermal resistance and conductivity than the original sample, although the dendrimer coverage of the SiQDs might partially shield such effects. Moreover, the permanence of SiQDs nanoparticles in the structure of the cellulosic support in aqueous environments and their effect on diffusive transport were determined by water uptake as well as by membrane potential measurements at different concentrations of a model electrolyte (KCl). These results demonstrate the possible use of these stable nano-engineered membranes, which are based on SiQDs nanoparticles, in electrochemical devices under flow conditions. PMID:27474642

  8. Separation of isomeric xylenes by pervaporation through cellulose ester membranes

    NARCIS (Netherlands)

    Mulder, M.H.V.; Kruitz, F.; Smolders, C.A.

    1982-01-01

    The interaction between the isomeric xylenes and different cellulose esters was investigated using solubility parameter considerations and through measurements of swelling values. p]Hansen's three-dimensional solubility parameters δd, δp, δh of all the components have been calculated. These values h

  9. Effect of Electron-Beam Irradiation on Bacterial Cellulose Membranes Used as Transdermal Drug Delivery Systems

    International Nuclear Information System (INIS)

    Multiple methods are used to modify material surfaces. Radiation is an effective tool for polymer surfaces modification in order to obtain transdermal systems with different controlled release properties. Bacterial cellulose is a promising biomaterial synthesized by Acetobacter xylinum. It has a distinctive ultrafine reticulated structure that may become a perfect matrix as an optimal wound healing environment. In this work, high energy irradiation (γ rays from 137Cs) was applied to modify bacterial cellulose membranes. The effect of varying irradiation doses on membranes permeability was studied. Tetracycline was involved in the study of diffusivity as model drug. Release and permeation of drug from irradiated and non-irradiated membranes were done using a diffusion cell. The membrane permeability was determined using a psudo-steady state analysis based on Fick's law

  10. Controlled release and antibacterial activity of tetracycline hydrochloride-loaded bacterial cellulose composite membranes.

    Science.gov (United States)

    Shao, Wei; Liu, Hui; Wang, Shuxia; Wu, Jimin; Huang, Min; Min, Huihua; Liu, Xiufeng

    2016-07-10

    Bacterial cellulose (BC) is widely used in biomedical applications. In this study, we prepared an antibiotic drug tetracycline hydrochloride (TCH)-loaded bacterial cellulose (BC) composite membranes, and evaluated the drug release, antibacterial activity and biocompatibility. The structure and morphology of the fabricated BC-TCH composite membranes were characterized using scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR). The TCH release results show that the incorporation of BC matrix to load TCH is able to control the release. In vitro antibacterial assay demonstrate that the developed BC-TCH composites displayed excellent antibacterial activity solely associated with the loaded TCH drug. More importantly, the BC-TCH composite membranes display good biocompatibility. These characteristics of BC-TCH composite membranes indicate that they may successfully serve as wound dressings and other medical biomaterials. PMID:27106158

  11. Performance of cellulose acetate butyrate membranes in hyperfiltration of sodium chloride and urea feed solution

    Science.gov (United States)

    Wydeven, T.; Leban, M.

    1973-01-01

    Cellulose acetate butyrate (CAB) membranes are shown to give high salt and urea rejection with water flux of about 3 gallons/sq ft per day at 600 psig. Membranes prepared from a formulation containing glyoxal show a significant increase in flux and decrease in salt and urea rejection with drying time. Zero drying time gives maximum urea and salt rejection and is therefore most suitable for hyperfiltration of sodium chloride and urea feed solution.

  12. Chitosan-based nanofibrous membranes for antibacterial filter applications

    OpenAIRE

    Cooper, Ashleigh; Oldinski, Rachael; Ma, Hongyan; Bryers, James D.; Zhang, Miqin

    2012-01-01

    Nanofibrous membranes have drawn considerable interest for filtration applications due to their ability to withstand high fluid flux while removing micro- and nano-sized particulates from solution. The desire to introduce an antibacterial function into water filter applications presents a challenge to widespread application of fibrous membranes because the addition of chemicals or biocides may produce harmful byproducts downstream. Here, we report the development of chitosan-polycaprolactone ...

  13. Transport of Carbonate Ions by Novel Cellulose Fiber Supported Solid Membrane

    Directory of Open Access Journals (Sweden)

    A. G. Gaikwad

    2012-06-01

    Full Text Available Transport of carbonate ions was explored through fiber supported solid membrane. A novel fiber supported solid membrane was prepared by chemical modification of cellulose fiber with citric acid, 2′2-bipyridine and magnesium carbonate. The factors affecting the permeability of carbonate ions such as immobilization of citric acid-magnesium metal ion -2′2-bipyridine complex (0 to 2.5 mmol/g range over cellulose fiber, carbon-ate ion concentration in source phase and NaOH concentration in receiving phase were investigated. Ki-netic of carbonate, sulfate, and nitrate ions was investigated through fiber supported solid membrane. Transport of carbonate ions with/without bubbling of CO2 (0 to 10 ml/min in source phase was explored from source to receiving phase. The novel idea is to explore the adsorptive transport of CO2 from source to receiving phase through cellulose fiber containing magnesium metal ion organic framework. Copyright © 2012 BCREC UNDIP. All rights reserved.Received: 25th November 2011; Revised: 17th December 2011; Accepted: 19th December 2011[How to Cite: A.G. Gaikwad. (2012. Transport of Carbonate Ions by Novel Cellulose Fiber Supported Solid Membrane. Bulletin of Chemical Reaction Engineering & Catalysis, 7 (1: 49– 57.  doi:10.9767/bcrec.7.1.1225.49-57][How to Link / DOI: http://dx.doi.org/10.9767/bcrec.7.1.1225.49-57 ] | View in 

  14. Chitosan-based nanofibrous membranes for antibacterial filter applications.

    Science.gov (United States)

    Cooper, Ashleigh; Oldinski, Rachael; Ma, Hongyan; Bryers, James D; Zhang, Miqin

    2013-01-30

    Nanofibrous membranes have drawn considerable interest for filtration applications due to their ability to withstand high fluid flux while removing micro- and nano-sized particulates from solution. The desire to introduce an antibacterial function into water filter applications presents a challenge to widespread application of fibrous membranes because the addition of chemicals or biocides may produce harmful byproducts downstream. Here, we report the development of chitosan-polycaprolactone (PCL) nanofibrous membranes to utilize the natural antibacterial property of chitosan for antibacterial water filtration. Chitosan-PCL fibers with diameters of 200-400 nm and chitosan contents of 25, 50 and 75 wt% were prepared by electrospinning. In a series of bacterial challenge tests, chitosan-PCL fibrous membranes significantly reduced Staphylococcus aureus adhesion compared to PCL fibrous membranes. In water permeability and particulate size removal tests, fibrous membranes with 25% chitosan supported the greatest water flux (∼7000 L/h/m(2)) with 100% removal of 300-nm particulates, while maintaining the membrane integrity. This study demonstrates the potential of chitosan-PCL nanofibrous membranes as pre-filters for water filtration systems that demonstrate combinatorial filtration and intrinsic antibacterial advantages. PMID:23218292

  15. Novel carboxymethyl cellulose based nanocomposite membrane: Synthesis, characterization and application in water treatment.

    Science.gov (United States)

    Saber-Samandari, Samaneh; Saber-Samandari, Saeed; Heydaripour, Samira; Abdouss, Majid

    2016-01-15

    Significant efforts have been made to develop composite membranes with high adsorption efficiencies for water treatment. In this study, a carboxymethyl cellulose-graft-poly(acrylic acid) membrane was synthesized in the presence of silica gel, which was used as an inorganic support. Then, different amounts of bentonite were introduced to the carboxymethyl cellulose (CMC) grafted networks as a multifunctional crosslinker, and nanocomposite membranes were prepared. The nanocomposite membranes were characterized using Fourier transform infrared spectroscopy, and scanning electron microscopy, which revealed their compositions and surface morphologies. The novel synthesized nanocomposite membranes were utilized as adsorbents for the removal of crystal violet (CV) and cadmium (Cd (II)) ions, which were selected as representatives of a dye and a heavy metal, respectively. We explored the effects of various parameters, such as time, pH, temperature, initial concentration of adsorbate solution and amount of adsorbent, on membrane adsorption capacity. Furthermore, the kinetic, adsorption isotherm models and thermodynamic were employed for the description of adsorption processes. The maximum adsorption capacities of membranes for CV and Cd (II) ions were found to be 546 and 781 mg g(-1), respectively. The adsorption of adsorbate ions by all types of nanocomposite membranes followed pseudo-second-order kinetic model and was best fit with the Freundlich adsorption isotherm. The results indicated that the synthesized nanocomposite membrane is an efficient adsorbent for the removal of cationic dye and metal contaminants from aqueous solution during water treatment. PMID:26560638

  16. Novel cellulose reinforcement for polymer electrolyte membranes with outstanding mechanical properties

    International Nuclear Information System (INIS)

    Highlights: ► UV-cured methacrylic-based composite gel-polymer electrolyte membranes for rechargeable lithium batteries. ► Excellent mechanical stability by reinforcement with classical cellulose handsheets. ► Fast and environmentally friendly preparation process, green and low cost cellulose reinforcement. ► Good electrochemical behaviour, stable cyclability and long-term performances in real battery configuration. - Abstract: Methacrylic-based thermo-set gel-polymer electrolytes obtained by an easy and reliable free radical photo-polymerisation process demonstrate good behaviour in terms of ionic conductivity, interfacial stability with the Li-metal electrode and cyclability in lithium cells. Though the obtained membranes are flexible, self standing and easy to handle, there is room for improving mechanical strength. In this respect, a novel approach is adopted in this work, in which a cellulose hand-sheet (paper), specifically designed for the specific application, is used as a composite reinforcing agent. To enhance its compatibility with the polymer matrix, cellulose is modified by UV-grafting of poly(ethylene glycol) methyl ether methacrylate on it. Excellent mechanical properties are obtained and good overall electrochemical performances are maintained; highlighting that such specific approach would make these hybrid organic, green, cellulose-based composite polymer electrolyte systems a strong contender in the field of thin and flexible Li-based power sources.

  17. The effect of using different 0.45 μm filter membranes on 'dissolved' element concentrations in natural waters

    Science.gov (United States)

    Hall, G.E.M.; Bonham-Carter, G. F.; Horowitz, A.J.; Lum, K.; Lemieux, C.; Quemerais, B.; Garbarino, J.R.

    1996-01-01

    The effect of 4 different 0.45 ??m pore size filter membrane systems on the 'dissolved' concentration of 28 elements in 5 natural water samples of varying matrix is reported. In 3 of the 5 waters, consistently higher concentrations of most elements (minor and trace) are obtained using Nucleopore 47 mm filter and the cellulose acetate/nitrate 47 mm filter than those measured using the 142 mm cellulose nitrate MFS filter or the Gelman capsule 47 mm filter. These distinct and coherent patterns in elemental behaviour disappear for the other 2 samples, an organic-rich peat water of high suspended load and a mineralised sample high in Si and Ca. Thus the nature and degree of filtration artifacts is matrix-dependent. These trends are evident in both data sets produced by 2 independent laboratories using different instrumentation, techniques and calibrating procedures. The average relative standard deviation in elemental concentration across the 4 filter types is in the range 9-21%. The presence of such filtration artifacts must be considered in projects where, for example, seasonal variability of water composition is under examination, data from various sources are being merged or hydrogeochemical surveys are being conducted.

  18. Chain scission and anti fungal effect of electron beam on cellulose membrane

    Science.gov (United States)

    Wanichapichart, Pikul; Taweepreeda, Wirach; Nawae, Safitree; Choomgan, Pastraporn; Yasenchak, Dan

    2012-08-01

    Two types of bacterial cellulose (BC) membranes were produced under a modified H&S medium using sucrose as a carbon source, with (CCB) and without (SHB) coconut juice supplement. Both membranes showed similar crystallinity of 69.24 and 71.55%. After being irradiated with E-beams under oxygen limited and ambient condition, the results from water contact angle showed that only the irradiated membrane CCB was increased from 30 to 40 degrees, and irradiation under oxygen ambient condition provided the greatest value. Comparing with the control membranes, smaller water flux was the cases after electron beam irradiation which indicated a reduction of membrane pore area. However, the results from molecular weight cut off (MWCO) revealed that chain scission was greater for membrane SHB and its cut off was increased from 28,000 Da to more than 35,000 Da. FTIR analysis revealed some changes in membrane functional groups, corresponding with the above results. These changes initiated new property of cellulose membranes, an anti-fungal food wrap.

  19. Self-sterilized composite membranes of cellulose acetate/polyethylene glycol for water desalination.

    Science.gov (United States)

    Ahmad, Adnan; Jamshed, Fahad; Riaz, Tabinda; Gul, Sabad-E-; Waheed, Sidra; Sabir, Aneela; AlAnezi, Adnan Alhathal; Adrees, Muhammad; Jamil, Tahir

    2016-09-20

    Cellulose acetate/Polyethylene glycol-600 composite membranes were fabricated by two step phase inversion procedure and modified by in-situ reduction of silver nitrate. FTIR spectra demonstrated the existence of functional groups for bonding of silver with oxygen at 370cm(-1), 535cm(-1). The XRD diffractogram indicates characteristic peaks at 2θ values of 38.10°, 44.30°, 64.40°, and 77.30° which confirm the successful incorporation of silver within matrix of composite membranes. The morphology of composite membranes with appearances of spongy voids was exemplified from the scanning electron microscope. The atomic force microscopy was used to determine the increase in the surface roughness of the membranes. The increase in hydrophilicity, measured through contact angle, is rendered to the embedment of silver. The modification of membranes increased the flux from 0.80 to 0.95L/hr.m(2). The resulting membranes have outstanding ability to fight against gram negative Escherichia Coli and Bacillus Sabtilus. The novel cellulose acetate/polyethylene glycol membranes customized with silver have paved the path for evolution of axenic membranes. PMID:27261744

  20. Flexible magnetic membranes based on bacterial cellulose and its evaluation as electromagnetic interference shielding material

    International Nuclear Information System (INIS)

    Flexible magnetic membranes with high proportion of magnetite were successfully prepared by previous impregnation of the never dried bacterial cellulose pellicles with ferric chloride followed by reduction with sodium bisulfite and alkaline treatment for magnetite precipitation. Membranes were characterized by Raman spectroscopy, Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), vibrating magnetometer, field emission scanning electron microscopy (FEG-SEM) and impedance spectroscopy. Microwave properties of these membranes were investigated in the X-band (8.2 to 12.4 GHz). FEG-SEM micrographs show an effective coverage of the BC nanofibers by Fe3O4 nanoparticles. Membranes with up to 75% in weight of particles have been prepared after 60 min of reaction. Magnetite nanoparticles in the form of aggregates well adhered to the BC fibers were observed by SEM. The average crystal sizes of the magnetic particles were in the range of 10 ± 1 to 13 ± 1 nm (estimated by XRD). The magnetic particles in the BC pellicles presented superparamagnetic behavior with a saturation magnetization in the range of 60 emu g−1 and coercive force around 15 Oe. These magnetic pellicles also displayed high electrical permittivity and a potential application as microwave absorber materials. - Highlights: • Bacterial cellulose/magnetite nanocomposites with high incorporation degree of nanoparticles. • Magnetite nanoparticles well adhered to the surface of bacterial cellulose nanofibers. • A saturation magnetization of the nanoparticles in the BC pellicles of about 60 emu g−1. • Flexible membranes with high super-paramagnetic characteristic

  1. Polyethylenimine coated bacterial cellulose nanofiber membrane and application as adsorbent and catalyst.

    Science.gov (United States)

    Wang, Jianqiang; Lu, Xinkun; Ng, Pui Fai; Lee, Ka I; Fei, Bin; Xin, John H; Wu, Jian-yong

    2015-02-15

    Bacterial cellulose (BC) nanofiber membranes were simply aminalized by a flush-coating and post-crosslinking method. Firstly, wet BC membranes were flushed through by an aqueous solution of polyethylenimine (PEI) and glycerol diglycidyl ether (GDE) under vacuum suction, then further heated up to 70 °C to crosslink the resultant coating on the surface of the nanofibers. The PEI coated bacterial cellulose (BC@PEI) nanofiber membrane presented excellent adsorption performance for Cu(2+) and Pb(2+) ions from aqueous solutions. Desorption of these ions was achieved using ethylene diamine tetraacetic acid treatment. This cycle of adsorption and desorption was repeated for several times with good remain adsorption performance (over 90%). Furthermore, the adsorbed Cu(2+) ions can be reduced to copper nanoparticles, and showed excellent catalytic performance for methylene blue reduction in aqueous solution. The catalytic performance can remained after several times of usage. PMID:25460686

  2. Production of bacterial cellulose membranes in a modified airlift bioreactor by Gluconacetobacter xylinus.

    Science.gov (United States)

    Wu, Sheng-Chi; Li, Meng-Hsun

    2015-10-01

    In this study, a novel bioreactor for producing bacterial cellulose (BC) is proposed. Traditional BC production uses static culture conditions and produces a gelatinous membrane. The potential for using various types of bioreactor, including a stirred tank, conventional airlift, and modified airlift with a rectangular wire-mesh draft tube, in large-scale production has been investigated. The BC obtained from these bioreactors is fibrous or in pellet form. Our proposed airlift bioreactor produces a membrane-type BC from Gluconacetobacter xylinus, the water-holding capacity of which is greater than that of cellulose types produced using static cultivation methods. The Young's modulus of the product can be manipulated by varying the number of net plates in the modified airlift bioreactor. The BC membrane produced using the proposed bioreactor exhibits potential for practical application. PMID:25823854

  3. Characterization of cellulose acetate micropore membrane immobilized acylase I

    Institute of Scientific and Technical Information of China (English)

    郭永胜; 王杰; 宋锡谨

    2004-01-01

    This paper describes an innovative method for the immobilization of acylase I, which was entrapped into the CA-CTA micropore membrane. The most suitable casting solutions proportion for immobilizing the enzyme was ob tained through orthogonal experiment. Properties of the enzyme membrane were investigated and compared with those of free enzyme and blank membrane. The thermal stability and pH stability of the enzyme inside the membrane were changed by immobilization. The optimum pH was found to be 6.0, which changes 1.0 unit compared with that of free acylase I. The optimum temperature was found to be about 90 ℃C, which is higher than that of free acylase I (60 ℃). Experimental results showed that immobilization had effects on the kinetic parameters of acylase I.

  4. Characterization of cellulose acetate micropore membrane immobilized acylase I

    Institute of Scientific and Technical Information of China (English)

    郭永胜; 王杰; 宋锡谨

    2004-01-01

    This paper describes an innovative method for the immobilization of acylase I, which was entrapped into the CA-CTA micropore membrane. The most suitable casting solutions proportion for immobilizing the enzyme was obtained through orthogonal experiment. Properties of the enzyme membrane were investigated and compared with those of free enzyme and blank membrane. The thermal stability and pH stability of the enzyme inside the membrane were changed by immobilization. The optimum pH was found to be 6.0, which changes 1.0 unit compared with that of free acylase I. The optimum temperature was found to be about 90℃, which is higher than that of free acylase I (60℃). Experimental results showed that immobilization had effects on the kinetic parameters of acylase I.

  5. Surface hydrophobic modification of cellulose membranes by plasma-assisted deposition of hydrocarbon films

    Directory of Open Access Journals (Sweden)

    Mudtorlep Nisoa

    2010-03-01

    Full Text Available Surface modification by plasma polymerization is an efficient method to change the surface properties of a membrane. Desirable functionality such as hydrophobicity or hydrophilicity can be obtained, depending on plasma chemistry of gas precursors and discharge conditions. In this work, RF magnetron plasma is produced using acetylene and nitrogen as precursor gases. Variations of RF power, particle flux, deposited time and pressure of the precursor gases have been made to observe coating effects on the cellulose membranes. When appropriated conditions are used, a thin brownish film of hydrocarbon was formed on the membrane, and the water contact angle increased from 35 to 130 degrees.

  6. Comparison of a new inorganic membrane filter (Anopore) with a track-etched polycarbonate membrane filter (Nuclepore) for direct counting of bacteria.

    OpenAIRE

    Jones, S E; Ditner, S A; Freeman, C.; Whitaker, C J; Lock, M A

    1989-01-01

    Bacterial counts obtained by using a new Anopore inorganic membrane filter were 21 to 33% higher than those obtained by using a Nuclepore polycarbonate membrane filter. In addition, the inorganic filter had higher flow rates, permitting lower vacuum pressures to be used, while the intrinsically flat, rigid surface resulted in easier focusing and sharp definition of bacteria across the whole field of view.

  7. Enhanced starch hydrolysis using α-amylase immobilized on cellulose ultrafiltration affinity membrane.

    Science.gov (United States)

    Konovalova, Viktoriia; Guzikevich, Kateryna; Burban, Anatoliy; Kujawski, Wojciech; Jarzynka, Karolina; Kujawa, Joanna

    2016-11-01

    In order to prepare ultrafiltration membranes possessing biocatalytic properties, α-amylase has been immobilized on cellulose membranes. Enzyme immobilization was based on a covalent bonding between chitosan and a surface of cellulose membrane, followed by an attachment of Cibacron Blue F3G-A dye as affinity ligand. Various factors affecting the immobilization process, such as enzyme concentration, pH of modifying solution, zeta-potential of membrane surface, and stability of immobilized enzyme were studied. The applicability of immobilized α-amylase has been investigated in ultrafiltration processes. The immobilization of α-amylase on membrane surface allows to increase the value of mass transfer coefficient and to decrease the concentration polarization effect during ultrafiltration of starch solutions. The enzyme layer on the membrane surface prevents a rapid increase of starch concentration due to the amylase hydrolysis of starch in the boundary layer. The presented affinity immobilization technique allows also for the regeneration of membranes from inactivated enzyme. PMID:27516322

  8. Effect of coagulant bath on the gas permeation properties of cellulose acetate asymmetric membrane

    Science.gov (United States)

    Mohamed, F.; Hasbullah, H.; Jami'an, W. N. R.; Salleh, W. N. H. W.; Ibrahim, N.; Ali, R. R.

    2016-06-01

    Membrane based gas separation process technology has been recognized as one of the most efficient and advanced unit operation for gas separation. One of the problems in membrane gas separation is membrane performance. This paper explores the application of cellulose acetate (CA) membrane for natural gas purification and separation by improving its permeability and selectivity. The main interest in this research is to study the effect of quench medium on the gas separation performance towards its physical characteristics and gas separation performance of CA membrane. Cellulose acetate polymer was dissolved in n- methyl-2-pyrrolidone solvent and casted onto a glass plate using a pneumatically controlled casting system with fixed shear rate and solvent evaporation times. The parameter varied was the non-solvent used as quench medium during membrane post treatment that were methanol and n-hexane. The different quench media as post treatment affected the O2 and N2 gas permeation and O2/N2 selectivity as well as the tensile strength of the flat sheet asymmetric membrane. Combination of methanol and n-hexane as quench media gave the best result than the other steps. This solvent exchange step influenced the morphology by producing thin skin layer and thus gives better gas separation performance than other steps

  9. Determination of sterilization dose of cellulose microbial membrane by electron beam irradiation using ISO 11137

    International Nuclear Information System (INIS)

    The calculation of sterilization dose of cellulose microbial by electron beam irradiation has been done based on International Organization for Standardization (ISO) 11137. Cellulose microbial pellicle was prepared by static fermentation of A. xylinum in a medium containing coconut water as a micro nutrient source. The pellicle was then hand pressed at ambient temperature in order to get membrane with thickness of 0.03 ± 0.01 mm. Sterilization dose of electron beam was determined based on ISO 11137 through three steps: calculation of bioburden, determination of verification dose and sterilization dose based on Table 2. The results showed that the average bioburden of batch 1, 2 and 3 were 67.4; 92.6; 91 cfu, respectively and overall average bioburden was 83.7 cfu. The batch average bioburden was smaller than twice of overall average bioburden, so overall average of bioburden was used to determine the verification dose. Based on ISO 11137, the verification dose was at 7.8 kGy. The results of sterility test on 100 pieces of membranes after irradiated at verification dose, showed that only one membrane had positive bacteria growth. From these results, it can be concluded that sterilization dose of cellulose microbial membrane irradiated by electron beam with the SAL of 10-6 was 21 kGy. (author)

  10. Electrospinning of silver nanoparticles loaded highly porous cellulose acetate nanofibrous membrane for treatment of dye wastewater

    Science.gov (United States)

    Wang, Ke; Ma, Qian; Wang, Shu-Dong; Liu, Hua; Zhang, Sheng-Zhong; Bao, Wei; Zhang, Ke-Qin; Ling, Liang-Zhong

    2016-01-01

    In this paper, silver nanoparticles (NPs) were reduced form silver nitrate. Morphology and distribution of the synthesized silver NPs were characterized. In order to obtain cellulose acetate (CA), nanofibrous membrane with high effective adsorption performance to carry silver NPs for treatment of dye wastewater, different solvent systems were used to fabricate CA nanofibrous membranes with different morphologies and porous structures via electrospinning. Morphologies and structures of the obtained CA nanofibrous membranes were compared by scanning electron microscopy (SEM), which showed that CA nanofibrous membrane obtained from acetone/dichloromethane (1/2, v/v) was with the highly porous structure. SEM, energy-dispersive spectrometry and Fourier transform infrared spectrometry showed that the silver NPs were effectively incorporated in the CA nanofibrous membrane and the addition of silver NPs did not damage the porous structure of the CA nanofibrous membrane. Adsorption of dye solution (rhodamine B aqueous solution) revealed that the highly porous CA nanofibrous membrane exhibited effective adsorption performance and the addition of silver NPs did not affect the adsorption of the dye. Antibacterial property of the CA nanofibrous membrane showed that the silver-loaded highly porous CA nanofibrous membrane had remarkable antibacterial property when compared to the CA nanofibrous membrane without silver NPs. The silver-loaded highly porous CA nanofibrous membrane could be considered as an ideal candidate for treatment of the dye wastewater.

  11. Development of Cellulose/PVDF-HFP Composite Membranes for Advanced Battery Separators

    Science.gov (United States)

    Castillo, Alejandro; Agubra, Victor; Alcoutlabi, Mataz; Mao, Yuanbing

    Improvements in battery technology are necessary as Li-ion batteries transition from consumer electronic to vehicular and industrial uses. An important bottle-neck in battery efficiency and safety is the quality of the separators, which prevent electric short-circuits between cathode and anode, while allowing an easy flow of ions between them. In this study, cellulose acetate was dissolved in a mixed solvent with poly(vinylpyrrolidone) (PVP), and the mixture was forcespun in a peudo paper making process to yield nanofibrillated nonwoven mats. The mats were soaked in NaOH/Ethanol to strip PVP and regenerate cellulose from its acetate precursor. The cellulose mats were then dipped in poly(vinylidenefluoride-co-hexafluoropropylene) (PVDF-HFP) to yield the cellulose/PVDF-HFP composte membranes. These membranes were characterized chemically through FTIR spectroscopy and solvent-stability tests, thermally through DSC, physically by stress/strain measurements along with weight-based electrolyte uptake, and electrically by AC-impedance spectroscopy combined with capacitative cycling.

  12. Cellulose Acetate 398-10 Asymmetric Membrane Capsules for Osmotically Regulated Delivery of Acyclovir

    Directory of Open Access Journals (Sweden)

    Alka Sonkar

    2016-01-01

    Full Text Available The study was aimed at developing cellulose acetate asymmetric membrane capsules (AMCs of acyclovir for its controlled delivery at the absorption site. The AMCs were prepared by phase inversion technique using wet process. A 23 full factorial design assessed the effect of independent variables (level(s of polymer, pore former, and osmogen on the cumulative drug release from AMCs. The buoyant optimized formulation F7 (low level of cellulose acetate; high levels of both glycerol and sodium lauryl sulphate displayed maximum drug release of 97.88±0.77% in 8 h that was independent of variation in agitational intensity and intentional defect on the cellulose acetate AMC. The in vitro data best fitted zero-order kinetics (r2=0.9898. SEM micrograph of the transverse section confirmed the asymmetric nature of the cellulose acetate capsular membrane. Statistical analysis by Design Expert software indicated no interaction between the independent variables confirming the efficiency of the design in estimating the effects of variables on drug release. The optimized formulation F7 (desirability = 0.871 displayed sustenance of drug release over the drug packed in AMC in pure state proving the superiority of osmotically active formulation. Conclusively the AMCs have potential for controlled release of acyclovir at its absorption site.

  13. Comparison of concentration of ions in PM1 aerosol sampled on nitrate cellulose and teflon filters

    Czech Academy of Sciences Publication Activity Database

    Kořínková, Alena; Mikuška, Pavel; Večeřa, Zbyněk; Křůmal, Kamil

    Brno : Ústav analytické chemie AV ČR, v. v. i, 2012 - (Foret, F.; Křenková, J.; Guttman, A.; Klepárník, K.; Boček, P.), s. 248-249 ISBN 978-80-904959-1-3. [CECE 2012. International Interdisciplinary Meeting on Bioanalysis /9./. Brno (CZ), 01.11.2012-02.11.2012] R&D Projects: GA ČR(CZ) GAP503/11/2315; GA ČR(CZ) GBP503/12/G147 Institutional support: RVO:68081715 Keywords : aerosol * nitrate cellulose and teflon filter * ions Subject RIV: CB - Analytical Chemistry, Separation http://hdl.handle.net/11104/0214234

  14. Bacterial cellulose membrane as flexible substrate for organic light emitting devices

    International Nuclear Information System (INIS)

    Bacterial cellulose (BC) membranes produced by gram-negative, acetic acid bacteria (Gluconacetobacter xylinus), were used as flexible substrates for the fabrication of Organic Light Emitting Diodes (OLED). In order to achieve the necessary conductive properties indium tin oxide (ITO) thin films were deposited onto the membrane at room temperature using radio frequency (r.f.) magnetron sputtering with an r.f. power of 30 W, at pressure of 8 mPa in Ar atmosphere without any subsequent thermal treatment. Visible light transmittance of about 40% was observed. Resistivity, mobility and carrier concentration of deposited ITO films were 4.90 x 10-4 Ohm cm, 8.08 cm2/V-s and - 1.5 x 1021 cm-3, respectively, comparable with commercial ITO substrates. In order to demonstrate the feasibility of devices based on BC membranes three OLEDs with different substrates were produced: a reference one with commercial ITO on glass, a second one with a SiO2 thin film interlayer between the BC membrane and the ITO layer and a third one just with ITO deposited directly on the BC membrane. The observed OLED luminance ratio was: 1; 0.5; 0.25 respectively, with 2400 cd/m2 as the value for the reference OLED. These preliminary results show clearly that the functionalized biopolymer, biodegradable, biocompatible bacterial cellulose membranes can be successfully used as substrate in flexible organic optoelectronic devices

  15. Bacterial cellulose membrane as flexible substrate for organic light emitting devices

    Energy Technology Data Exchange (ETDEWEB)

    Legnani, C.; Vilani, C. [CeDO-Organic Device Center, Dimat-Dimat, Inmetro, Duque de Caxias, RJ (Brazil); Calil, V.L. [CeDO-Organic Device Center, Dimat-Dimat, Inmetro, Duque de Caxias, RJ (Brazil); LOEM-Molecular Optoelectronic Laboratory-Physics Department-PUC-Rio, Rio de Janeiro, RJ (Brazil); Barud, H.S. [Institute of Chemistry, Sao Paulo State University-UNESP, CP 355 Araraquara, SP (Brazil); Quirino, W.G. [CeDO-Organic Device Center, Dimat-Dimat, Inmetro, Duque de Caxias, RJ (Brazil); Achete, C.A. [CeDO-Organic Device Center, Dimat-Dimat, Inmetro, Duque de Caxias, RJ (Brazil); COPPE-Programa de Engenharia Metalurgica e de Materiais, UFRJ, Rio de Janeiro, RJ (Brazil); Ribeiro, S.J.L. [Institute of Chemistry, Sao Paulo State University-UNESP, CP 355 Araraquara, SP (Brazil); Cremona, M. [CeDO-Organic Device Center, Dimat-Dimat, Inmetro, Duque de Caxias, RJ (Brazil); LOEM-Molecular Optoelectronic Laboratory-Physics Department-PUC-Rio, Rio de Janeiro, RJ (Brazil)], E-mail: cremona@fis.puc-rio.br

    2008-12-01

    Bacterial cellulose (BC) membranes produced by gram-negative, acetic acid bacteria (Gluconacetobacter xylinus), were used as flexible substrates for the fabrication of Organic Light Emitting Diodes (OLED). In order to achieve the necessary conductive properties indium tin oxide (ITO) thin films were deposited onto the membrane at room temperature using radio frequency (r.f.) magnetron sputtering with an r.f. power of 30 W, at pressure of 8 mPa in Ar atmosphere without any subsequent thermal treatment. Visible light transmittance of about 40% was observed. Resistivity, mobility and carrier concentration of deposited ITO films were 4.90 x 10{sup -4} Ohm cm, 8.08 cm{sup 2}/V-s and - 1.5 x 10{sup 21} cm{sup -3}, respectively, comparable with commercial ITO substrates. In order to demonstrate the feasibility of devices based on BC membranes three OLEDs with different substrates were produced: a reference one with commercial ITO on glass, a second one with a SiO{sub 2} thin film interlayer between the BC membrane and the ITO layer and a third one just with ITO deposited directly on the BC membrane. The observed OLED luminance ratio was: 1; 0.5; 0.25 respectively, with 2400 cd/m{sup 2} as the value for the reference OLED. These preliminary results show clearly that the functionalized biopolymer, biodegradable, biocompatible bacterial cellulose membranes can be successfully used as substrate in flexible organic optoelectronic devices.

  16. 硅藻土/纤维素复合助滤剂在微污染原水处理中的应用%Application of diatomite/cellulose composite filter aids on micro-polluted raw water treatment

    Institute of Scientific and Technical Information of China (English)

    盛超; 李孟; 黄凌凤; 章蕾

    2016-01-01

    以硅藻土和纤维素为原料,通过溶胶-凝胶法制备出了新型硅藻土/纤维素复合助滤剂,探究了各种制备条件对助滤剂的影响,并在高岭土悬浊液中对硅藻土、纤维素和硅藻土/纤维素的助滤性能进行了比较,同时研究了硅藻土/纤维素助滤剂对实际微污染水过滤的影响。研究结果表明:复合助滤剂的最佳制备条件为纤硅比0.67,氨水浓度5.0×10-4 mol/L,蒸馏水/纤维素40 mL/g,EtOH/硅藻土20 mL/g,60℃恒温水浴;硅藻土/纤维素复合助滤剂的助滤性能要明显优于硅藻土和纤维素助滤剂;在微污染原水直接过滤过程中,投加硅藻土/纤维素助滤剂可提高各微污染物的去除率,结合微滤膜深度处理工艺,最终出水水质满足《生活饮用水卫生标准》(GB 5749—2006)的要求。%The diatomite/cellulose filter aids were prepared using raw diatomite and cellulose via sol-gel technique. The effect of cellulose/diatomite, distilled water/cellulose, EtOH/diatomite, ammonia concentration and temperature on the properties of diatomite/cellulose filter aids were investigated.The filtration efficiency of diatomite,cellulose and diatomite/cellulose filter aids was compared.The influence of diatomite/cellulose filter aids on slightly polluted water filtration was studied.Results indicated that when 40 mL distilled water dissolved 1.0 g cellulose,20 mLEtOH carried 1.5 g diatomite,the ratio of diatomite to cellulose was 0.67,the concentration of ammonia was 5×10-4mol/L,the temperature was 60 ℃,the best diatomite/cellulose filter aids were achieved.The efficiency of diatomite/cellulose filter aids was obviously better than that by diatomite and cellulose filter aids.The pollutants removal efficiency could increase by using the diatomite/cellulose filter aids in the direct filtration process to treat the micro-polluted raw water.The results showed that the combination of

  17. 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.

  18. 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.

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

    International Nuclear Information System (INIS)

    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

  20. Rotating carbon nanotube membrane filter for water desalination

    OpenAIRE

    Qingsong Tu; Qiang Yang; Hualin Wang; Shaofan Li

    2016-01-01

    We have designed a porous nanofluidic desalination device, a rotating carbon nanotube membrane filter (RCNT-MF), for the reverse osmosis desalination that can turn salt water into fresh water. The concept as well as design strategy of RCNT-MF is modeled, and demonstrated by using molecular dynamics simulation. It has been shown that the RCNT-MF device may significantly improve desalination efficiency by combining the centrifugal force propelled reverse osmosis process and the porous CNT-based...

  1. Activated sludge filterability and full-scale membrane bioreactor operation

    OpenAIRE

    Krzeminski, P.

    2013-01-01

    Despite continuous developments in the field of MBR technology, membrane fouling together with the associated energy demand and related costs issues remain major challenges. The efficiency of the filtration process in an MBR is governed by the activated sludge filterability, which is still limitedly understood and is determined by the interactions between the biomass, the wastewater and the applied process conditions. The purpose of this thesis is to increase understanding of the factors impa...

  2. In vivo and in vitro evaluation of an Acetobacter xylinum synthesized microbial cellulose membrane intended for guided tissue repair

    Directory of Open Access Journals (Sweden)

    de Lima-Neto João

    2009-03-01

    Full Text Available Abstract Background Barrier materials as cellulose membranes are used for guided tissue repair. However, it is essential that the surrounding tissues accept the device. The present study histologically evaluated tissue reaction to a microbial cellulose membrane after subcutaneous implantation in mice. Furthermore, the interaction between mesenchymal stem cells and the biomaterial was studied in vitro to evaluate its ability to act as cellular scaffold for tissue engineering. Methods Twenty-five Swiss Albino mice were used. A 10 × 10 mm cellulose membrane obtained through biosynthesis using Acetobacter xylinum bacteria was implanted into the lumbar subcutaneous tissue of each mouse. The mice were euthanatized at seven, 15, 30, 60, and 90 days, and the membrane and surrounding tissues were collected and examined by histology. Results A mild inflammatory response without foreign body reaction was observed until 30 days post-surgery around the implanted membrane. Polarized microscopy revealed that the membrane remained intact at all evaluation points. Scanning electron microscopy of the cellulose membrane surface showed absence of pores. The in vitro evaluation of the interaction between cells and biomaterial was performed through viability staining analysis of the cells over the biomaterial, which showed that 95% of the mesenchymal stem cells aggregating to the cellulose membrane were alive and that 5% were necrotic. Scanning electron microscopy showed mesenchymal stem cells with normal morphology and attached to the cellulose membrane surface. Conclusion The microbial cellulose membrane evaluated was found to be nonresorbable, induced a mild inflammatory response and may prove useful as a scaffold for mesenchymal stem cells.

  3. Bacterial cellulose nanofibrous membrane as thermal stable separator for lithium-ion batteries

    Science.gov (United States)

    Jiang, Fengjing; Yin, Lei; Yu, Qingchun; Zhong, Chunyan; Zhang, Junliang

    2015-04-01

    Thermal shrinkage is a severe problem for the conventional polyolefin separators. In this work, we report the excellent performance of bacterial cellulose (BC) nanofibrous membranes as separators for lithium (Li) ion batteries. Properties of BC separator including morphology, ionic conductivity, electrochemical stability, thermal stability, mechanical strength and battery charge-discharge performance are characterized and compared to a commercial separator membrane (Celgard® 2325). Because of the unique fibrous and cross-linked three-dimensional network structure, BC separator shows excellent dimensional stability up to 180 °C, good ionic conductivity and competitive battery performance.

  4. Mechanism of Fe crud deposition by membrane electrification in hollow fiber membrane filter

    International Nuclear Information System (INIS)

    The hollow fiber membrane filter (HFF) applied to the condensate polishing system in BWR plants occasionally experiences a greater pressure drop due to fouling of the membrane inner surface. Then a mechanism for fouling and its countermeasures were studied from simulated laboratory experiments. The HFF made of polyethylene polymer which has a dielectric property became negatively charged on its surface when pure water, such as condensate, flowed through the filter. The degree of the negative charge depended on the water electrical conductivity and flow velocity through the membrane. The amount of Fe hydroxide deposits on the membrane surface depended on the Fe and Cu ion concentrations. Then a crud precoating method was confirmed as an effective and practicable means to restrict deposits. (author)

  5. Separation of macromolecular proteins and removal of humic acid by cellulose acetate modified UF membranes.

    Science.gov (United States)

    Kanagaraj, P; Nagendran, A; Rana, D; Matsuura, T

    2016-08-01

    Surface modifying macromolecules (SMMs) were synthesized with various polyurethane pre polymers end-capped with different groups and blended into the casting solution of cellulose acetate (CA) to prepare surface modified ultra-filtration (UF) membranes for water filtration applications. The surface modification of the CA membranes was confirmed by the FTIR and static contact angle (SCA) measurements. The membranes so prepared had the typical characteristics of UF membranes as confirmed by scanning electron microscopy (SEM). Membrane properties were studied in terms of membrane compaction, percentage water content (%WC), pure water flux (PWF), membrane hydraulic resistance (Rm), molecular weight cut-off (MWCO), average pore size and porosity. The result showed that PWF, %WC, MWCO and pore size increased whereas the Rm decreased by the addition of SMMs. The significant effect of SMMs on the fouling by humic acid (HA) was also observed. It was found that the cSMM-3 membrane, in which SMM was synthesized with diethylene glycol (DEG) and hydroxyl benzene sulfonate (HBS) was blended, had the highest flux recovery ratio FRR (84.6%), as well as the lowest irreversible fouling (15.4%), confirming their improved antifouling properties. Thus, the SMM modified CA membranes had proven, to play an important role in the water treatment by UF. PMID:27118046

  6. Fabrication and performance of PET mesh enhanced cellulose acetate membranes for forward osmosis.

    Science.gov (United States)

    Li, Guoliang; Wang, Jun; Hou, Deyin; Bai, Yu; Liu, Huijuan

    2016-07-01

    Polyethylene terephthalate mesh (PET) enhanced cellulose acetate membranes were fabricated via a phase inversion process. The membrane fabrication parameters that may affect the membrane performance were systematically evaluated including the concentration and temperature of the casting polymer solution and the temperature and time of the evaporation, coagulation and annealing processes. The water permeability and reverse salt flux were measured in forward osmosis (FO) mode for determination of the optimal membrane fabrication conditions. The optimal FO membrane shows a typical asymmetric sandwich structure with a mean thickness of about 148.2μm. The performance of the optimal FO membrane was tested using 0.2mol/L NaCl as the feed solution and 1.5mol/L glucose as the draw solution. The membrane displayed a water flux of 3.47L/(m(2)·hr) and salt rejection of 95.48% in FO mode. While in pressure retarded osmosis (PRO) mode, the water flux was 4.74L/(m(2)·hr) and salt rejection 96.03%. The high ratio of water flux in FO mode to that in PRO mode indicates that the fabricated membrane has a lower degree of internal concentration polarization than comparable membranes. PMID:27372114

  7. Effect of evaporation time on cellulose acetate membrane for gas separation

    Science.gov (United States)

    Jami'an, W. N. R.; Hasbullah, H.; Mohamed, F.; Yusof, N.; Ibrahim, N.; Ali, R. R.

    2016-06-01

    Throughout this decades, membrane technology has been the desirable option among the others gas separation technologies. However, few issues have been raised regarding the membrane gas separation application including the trade-off between its permeability and selectivity and also its effects towards environment. Therefore, for this research, a biopolymer membrane for gas separation application will be developed with reasonably high on both permeability and selectivity. The main objective of this research is to study the effect of solvent evaporation time on the flat sheet asymmetric membrane morphology and gas separation performance. The membranes were produced by a simple dry/wet phase inversion technique using a pneumatically controlled casting system. The dope solution for the membrane casting was prepared by dissolving the cellulose acetate (CA) polymer in N-Methyl-2-pyrrolidone (NMP) and the solvent evaporation time was varied. Permeability and selectivity of the membrane was performed by using pure gases of carbon dioxide, CO2 and methane, CH4. The increase in solvent evaporation time had improved the membrane morphologies as the porosity of the membrane surface decrease and formation of a more mature skin layer. The gas permeation tests determined that increasing in solvent evaporation time had increased the selectivity of CO2/CH4 but reduce the permeability of both gases

  8. Effect of silica particle size in cellulose membrane for desalination process

    Science.gov (United States)

    Nurkhamidah, Siti; Rahmawati, Yeni; Taufany, Fadlilatul; Merta, I. Made Pendi Adi; Putra, Deffry Danius Dwi; Woo, Eamor M.

    2015-12-01

    Development of desalination technologies is very important for fulfilling future water demand. The objective of this research is to synthesis membrane for desalination process from cellulose acetate (CA) by blending with polyethylene glycol (PEG) and silica resulting CA/PEG/Silica composite membrane. In this study, the synthesis and characterization of composite membrane is attempt where membrane performance is investigated for reverse osmosis desalination of saline water. CA/PEG membrane with ratio 80/20 (wt%) was modified with three different particle sizes of silica: 0.007, 0.02, and 60 µm. Composite membranes were characterized for their hydrophilicity, functional groups and permeation properties. The experiment results show that hydrophilicity of CA/PEG membrane increases after the addition of silica as shown by the decreasing of contact angle and the increasing of silanol group. Hydrophilicity of composite membrane increases with the decreasing of particle size of silica. The best performance membrane is obtained by using silica with particle size of 0.02 µm.

  9. Metal nanoparticles/ionic liquid/cellulose: polymeric membrane for hydrogenation reactions

    Directory of Open Access Journals (Sweden)

    Marcos Alexandre Gelesky

    2014-01-01

    Full Text Available Rhodium and platinum nanoparticles were supported in polymeric membranes with 10, 20 and 40 µm thickness. The polymeric membranes were prepared combining cellulose acetate and the ionic liquid (IL 1-n-butyl-3-methylimidazolium bis(trifluoromethane sulfonylimide (BMI.(NTf2. The presence of metal nanoparticles induced an increase in the polymeric membrane surface areas. The increase of the IL content resulted in an improvement of elasticity and decrease in tenacity and toughness, whereas the stress at break was not affected. The presence of IL probably causes an increase in the separation between the cellulose molecules that result in a higher flexibility and processability of the polymeric membrane. The CA/IL/M(0 combinations exhibit an excellent synergistic effect that enhances the activity and durability of the catalyst for the hydrogenation of cyclohexene. The CA/IL/M(0 polymeric membrane displays higher catalytic activity (up to 7.353 h-1 for the 20 mm of CA/IL/Pt(0 and stability than the nanoparticles dispersed only in the IL.

  10. Recent advances in cellulose and chitosan based membranes for water purification: A concise review.

    Science.gov (United States)

    Thakur, Vijay Kumar; Voicu, Stefan Ioan

    2016-08-01

    Recently membrane technology has emerged as a new promising and pervasive technology due to its innate advantages over traditional technologies such as adsorption, distillation and extraction. In this article, some of the recent advances in developing polymeric composite membrane materials for water purification from natural polysaccharide based polymers namely cellulose derivatives and chitosan are concisely reviewed. The impact of human social, demographic and industrial evolution along with expansion through environment has significantly affected the quality of water by pollution with large quantities of pesticides, minerals, drugs or other residues. At the forefront of decontamination and purification techniques, we found the membrane materials from polymers as a potential alternative. In an attempt to reduce the number of technical polymers widely used in the preparation of membranes, many researchers have reported new solutions for desalination or retention of organic yeasts, based on bio renewable polymers like cellulose derivatives and chitosan. These realizations are presented and discussed in terms of the most important parameters of membrane separation especially water flux and retention in this article. PMID:27112861

  11. In situ synthesis of silver chloride nanoparticles into bacterial cellulose membranes

    Energy Technology Data Exchange (ETDEWEB)

    Hu Weili; Chen Shiyan; Li Xin; Shi Shuaike; Shen Wei; Zhang Xiang [State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, Key Laboratory of Textile Science and Technology (Ministry of Education), College of Materials Science and Engineering, Donghua University, Shanghai, 201620 (China); Wang Huaping, E-mail: wanghp@dhu.edu.cn [State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, Key Laboratory of Textile Science and Technology (Ministry of Education), College of Materials Science and Engineering, Donghua University, Shanghai, 201620 (China)

    2009-05-05

    In situ synthesis of silver chloride (AgCl) nanoparticles was carried out under ambient conditions in nanoporous bacterial cellulose (BC) membranes as nanoreactors. The growth of the nanoparticles was readily obtained by alternating dipping of BC membranes in the solution of silver nitrate or sodium chloride followed by a rinse step. X-ray diffraction (XRD) patterns indicated the existence of AgCl nanoparticles in the BC and scanning electron microscopy (SEM) images showed that the AgCl nanoparticles well dispersed on the surface of BC and penetrated into the BC network. The AgCl nanoparticle-impregnated BC membranes exhibited high hydrophilic ability and strong antimicrobial activity against Escherichia coli (Gram-negative) and Staphylococcus aureus (Gram-positive). The preparative procedure is facile and versatile, and provides a simple route to manufacturing of useful antimicrobial membranes, which would be a good alternative for antimicrobial wound dressing.

  12. In situ synthesis of silver chloride nanoparticles into bacterial cellulose membranes

    International Nuclear Information System (INIS)

    In situ synthesis of silver chloride (AgCl) nanoparticles was carried out under ambient conditions in nanoporous bacterial cellulose (BC) membranes as nanoreactors. The growth of the nanoparticles was readily obtained by alternating dipping of BC membranes in the solution of silver nitrate or sodium chloride followed by a rinse step. X-ray diffraction (XRD) patterns indicated the existence of AgCl nanoparticles in the BC and scanning electron microscopy (SEM) images showed that the AgCl nanoparticles well dispersed on the surface of BC and penetrated into the BC network. The AgCl nanoparticle-impregnated BC membranes exhibited high hydrophilic ability and strong antimicrobial activity against Escherichia coli (Gram-negative) and Staphylococcus aureus (Gram-positive). The preparative procedure is facile and versatile, and provides a simple route to manufacturing of useful antimicrobial membranes, which would be a good alternative for antimicrobial wound dressing.

  13. Flexible magnetic membranes based on bacterial cellulose and its evaluation as electromagnetic interference shielding material

    Energy Technology Data Exchange (ETDEWEB)

    Marins, Jéssica A., E-mail: Jessica.amarins@gmail.com [Universidade Federal do Rio de Janeiro/ Instituto de Macromoléculas, Centro de Tecnologia, Rio de Janeiro, RJ (Brazil); Soares, Bluma G., E-mail: bluma@ima.ufrj.br [Universidade Federal do Rio de Janeiro/ Instituto de Macromoléculas, Centro de Tecnologia, Rio de Janeiro, RJ (Brazil); Barud, Hernane S.; Ribeiro, Sidney J.L. [Universidade Estadual Paulista, Instituto de Química, UNESP, Araraquara, SP (Brazil)

    2013-10-15

    Flexible magnetic membranes with high proportion of magnetite were successfully prepared by previous impregnation of the never dried bacterial cellulose pellicles with ferric chloride followed by reduction with sodium bisulfite and alkaline treatment for magnetite precipitation. Membranes were characterized by Raman spectroscopy, Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), vibrating magnetometer, field emission scanning electron microscopy (FEG-SEM) and impedance spectroscopy. Microwave properties of these membranes were investigated in the X-band (8.2 to 12.4 GHz). FEG-SEM micrographs show an effective coverage of the BC nanofibers by Fe{sub 3}O{sub 4} nanoparticles. Membranes with up to 75% in weight of particles have been prepared after 60 min of reaction. Magnetite nanoparticles in the form of aggregates well adhered to the BC fibers were observed by SEM. The average crystal sizes of the magnetic particles were in the range of 10 ± 1 to 13 ± 1 nm (estimated by XRD). The magnetic particles in the BC pellicles presented superparamagnetic behavior with a saturation magnetization in the range of 60 emu g{sup −1} and coercive force around 15 Oe. These magnetic pellicles also displayed high electrical permittivity and a potential application as microwave absorber materials. - Highlights: • Bacterial cellulose/magnetite nanocomposites with high incorporation degree of nanoparticles. • Magnetite nanoparticles well adhered to the surface of bacterial cellulose nanofibers. • A saturation magnetization of the nanoparticles in the BC pellicles of about 60 emu g{sup −1}. • Flexible membranes with high super-paramagnetic characteristic.

  14. Cellulose Acetate Membrane with Improved Perm-selectivity through Modification Dope Composition and Solvent Evaporation for Water Softening

    OpenAIRE

    T. D. Kusworo; Budiyono, A.I. Wibowo; G.D. Harjanto; A.D. Yudisthira; F.B. Iswanto

    2014-01-01

    Membrane technology has been developed because applicated on several fields. Hence, in this study carried the production of cellulose acetate nano-filtration membranes for water softening. The main objective of this study was determined the effect of solvent evaporation time and the effect of adding PEG to the morphology and perm-selectivity of asymmetry membrane for water treatment. Membranes prepared by dry/wet phase inversion method with variation of solvent evaporation time of 10-15 sec a...

  15. Uranium removal from water using cellulose triacetate membranes added with activated carbon

    Energy Technology Data Exchange (ETDEWEB)

    Villalobos-Rodriguez, R. [Centro de Investigacion en Materiales Avanzados, Miguel de Cervantes 120, Compl. Ind. Chihuahua, CP 31109, Chihuahua, Chih. (Mexico); Montero-Cabrera, M.E., E-mail: elena.montero@cimav.edu.mx [Centro de Investigacion en Materiales Avanzados, Miguel de Cervantes 120, Compl. Ind. Chihuahua, CP 31109, Chihuahua, Chih. (Mexico); Esparza-Ponce, H.E.; Herrera-Peraza, E.F. [Centro de Investigacion en Materiales Avanzados, Miguel de Cervantes 120, Compl. Ind. Chihuahua, CP 31109, Chihuahua, Chih. (Mexico); Ballinas-Casarrubias, M.L. [Facultad de Ciencias Quimicas, Universidad Autonoma de Chihuahua, Nuevo Campus s/n, Chihuahua, Chih. (Mexico)

    2012-05-15

    Ultrafiltration removal of uranium from water, with composite activated carbon cellulose triacetate membranes (AC-CTA), was investigated. The filtrate was provided by uraninite dissolution with pH=6-8. Removal efficiencies were calculated measuring solutions' radioactivities. Membranes were mainly characterized by microscopy analysis, revealing iron after permeation. Uranyl removal was 35{+-}7%. Chemical speciation indicates the presence of (UO{sub 2}){sub 2}CO{sub 3}(OH){sub 3}{sup -}, UO{sub 2}CO{sub 3}, UO{sub 2}(CO{sub 3}){sub 2}{sup 2-} and Fe{sub 2}O{sub 3}(s) as main compounds in the dissolution, suggesting co-adsorption of uranium and iron by the AC during filtration, as the leading rejection path. - Highlights: Black-Right-Pointing-Pointer Cellulose triacetate (CTA) and activated carbon (AC) composite membranes were suitable for uranium removal. Black-Right-Pointing-Pointer Up to 35% of uranium from low concentrated solutions was rejected by ultrafiltration. Black-Right-Pointing-Pointer Rejection is performed by a hybrid mechanism regulated by AC adsorption. Black-Right-Pointing-Pointer Uranium and iron speciation and predominance determines the adsorption in the membrane.

  16. Uranium removal from water using cellulose triacetate membranes added with activated carbon

    International Nuclear Information System (INIS)

    Ultrafiltration removal of uranium from water, with composite activated carbon cellulose triacetate membranes (AC-CTA), was investigated. The filtrate was provided by uraninite dissolution with pH=6–8. Removal efficiencies were calculated measuring solutions' radioactivities. Membranes were mainly characterized by microscopy analysis, revealing iron after permeation. Uranyl removal was 35±7%. Chemical speciation indicates the presence of (UO2)2CO3(OH)3−, UO2CO3, UO2(CO3)22− and Fe2O3(s) as main compounds in the dissolution, suggesting co-adsorption of uranium and iron by the AC during filtration, as the leading rejection path. - Highlights: ► Cellulose triacetate (CTA) and activated carbon (AC) composite membranes were suitable for uranium removal. ► Up to 35% of uranium from low concentrated solutions was rejected by ultrafiltration. ► Rejection is performed by a hybrid mechanism regulated by AC adsorption. ► Uranium and iron speciation and predominance determines the adsorption in the membrane.

  17. X-ray fluorescence determination of Au, Pd and Pt from chloride solutions after preconcentration on cellulose filters

    International Nuclear Information System (INIS)

    The aim of this work was synthesis of new sorption cellulose filters for dynamic preconcentration of Au, Pd and Pt from chloride solutions and subsequent XRF determination of these elements on the filters. New filters were prepared by impregnation of a filter paper with solution of tri-n-octylamine and paraffin in hexane (TOA-filters). The effect of paraffin and TOA concentration in hexane on a content of nitrogen in a filter was studied. It was found that Au(III), Pd(II) and Pt(IV) were quantitatively recovered on the TOA-filters (filtering surface diameter of 23 mm, thickness of 0.15 mm) from 0.5 - 1 M HCl at a flow rates of 2-5 ml min-1 from 10-100 ml of solution. The mathematical model of sorption dynamics was offered for the estimation of potential possibilities of new impregnated sorbents and for the evaluation of optimum dynamic conditions allowing to achieve of maximum concentration efficiency (CEmax). The elements were determined directly on the filters by XRF spectrometer. Palladium was also determined on the TOA-filters after formation of coloured compounds of metal with 4-(2-pyridylazo)resorcinol (PAR) by diffuse reflectance spectroscopy with the calculation of calorimetric characteristics and using test-scale. (authors)

  18. Stretchable and strong cellulose nanopaper structures based on polymer-coated nanofiber networks: an alternative to nonwoven porous membranes from electrospinning.

    Science.gov (United States)

    Sehaqui, Houssine; Morimune, Seira; Nishino, Takashi; Berglund, Lars A

    2012-11-12

    Nonwoven membranes based on electrospun fibers are of great interest in applications such as biomedical, filtering, and protective clothing. The poor mechanical performance is a limitation, as is some of the electrospinning solvents. To address these problems, porous nonwoven membranes based on nanofibrillated cellulose (NFC) modified by a hydroxyethyl cellulose (HEC) polymer coating are prepared. NFC/HEC aqueous suspensions are subjected to simple vacuum filtration in a paper-making fashion, followed by supercritical CO(2) drying. These nonwoven nanocomposite membranes are truly nanostructured and exhibit a nanoporous network structure with high specific surface area, as analyzed by nitrogen adsorption and FE-SEM. Mechanical properties evaluated by tensile tests show high strength combined with remarkably high strain to failure of up to 55%. XRD analysis revealed significant fibril realignment during tensile stretching. After postdrawing of the random mats, the modulus and strength are strongly increased. The present preparation route uses components from renewable resources, is environmentally friendly, and results in permeable membranes of exceptional mechanical performance. PMID:23046114

  19. UV-cured Al2O3-laden cellulose reinforced polymer electrolyte membranes for Li-based batteries

    International Nuclear Information System (INIS)

    A methacrylate based plasticised polymer electrolyte membrane is prepared via a rapid and facile UV curing process, the major concerns of mechanical integrity are overcome by simply using appropriately modified cellulose handsheet laden with nano-sized acidic alumina particles as a reinforcement. The use of the cellulose handsheets greatly enhances the flexibility and mechanical properties of the membrane while the addition of alumina particles helps to maintain satisfactory conductivity values. The reinforced composite electrolyte membrane is also tested in a real lithium cell, exhibiting excellent performance which account for its use in futuristic lithium batteries having low cost, environmentally friendly and easily scalable properties

  20. Rotating carbon nanotube membrane filter for water desalination.

    Science.gov (United States)

    Tu, Qingsong; Yang, Qiang; Wang, Hualin; Li, Shaofan

    2016-01-01

    We have designed a porous nanofluidic desalination device, a rotating carbon nanotube membrane filter (RCNT-MF), for the reverse osmosis desalination that can turn salt water into fresh water. The concept as well as design strategy of RCNT-MF is modeled, and demonstrated by using molecular dynamics simulation. It has been shown that the RCNT-MF device may significantly improve desalination efficiency by combining the centrifugal force propelled reverse osmosis process and the porous CNT-based fine scale selective separation technology. PMID:27188982

  1. Rotating carbon nanotube membrane filter for water desalination

    Science.gov (United States)

    Tu, Qingsong; Yang, Qiang; Wang, Hualin; Li, Shaofan

    2016-05-01

    We have designed a porous nanofluidic desalination device, a rotating carbon nanotube membrane filter (RCNT-MF), for the reverse osmosis desalination that can turn salt water into fresh water. The concept as well as design strategy of RCNT-MF is modeled, and demonstrated by using molecular dynamics simulation. It has been shown that the RCNT-MF device may significantly improve desalination efficiency by combining the centrifugal force propelled reverse osmosis process and the porous CNT-based fine scale selective separation technology.

  2. Electrospun cellulose acetate composites containing supported metal nanoparticles for antifungal membranes.

    Science.gov (United States)

    Quirós, Jennifer; Gonzalo, Soledad; Jalvo, Blanca; Boltes, Karina; Perdigón-Melón, José Antonio; Rosal, Roberto

    2016-09-01

    Electrospun cellulose acetate composites containing silver and copper nanoparticles supported in sepiolite and mesoporous silica were prepared and tested as fungistatic membranes against the fungus Aspergillus niger. The nanoparticles were in the 3-50nm range for sepiolite supported materials and limited by the size of mesopores (5-8nm) in the case of mesoporous silica. Sepiolite and silica were well dispersed within the fibers, with larger aggregates in the micrometer range, and allowed a controlled release of metals to create a fungistatic environment. The effect was assessed using digital image analysis to evaluate fungal growth rate and fluorescence readings using a viability stain. The results showed that silver and copper nanomaterials significantly impaired the growth of fungi when the spores were incubated either in direct contact with particles or included in cellulose acetate composite membranes. The fungistatic effect took place on germinating spores before hyphae growth conidiophore formation. After 24h the cultures were separated from fungistatic materials and showed growth impairment only due to the prior exposure. Growth reduction was important for all the particles and membranes with respect to non-exposed controls. The effect of copper and silver loaded materials was not significantly different from each other with average reductions around 70% for bare particles and 50% for membranes. Copper on sepiolite was particularly efficient with a decrease of metabolic activity of up to 80% with respect to controls. Copper materials induced rapid maturation and conidiation with fungi splitting in sets of subcolonies. Metal-loaded nanomaterials acted as reservoirs for the controlled release of metals. The amount of silver or copper released daily by composite membranes represented roughly 1% of their total load of metals. Supported nanomaterials encapsulated in nanofibers allow formulating active membranes with high antifungal performance at the same time

  3. Development of cellulose-polypyrrole microfiber membranes and assessment of their capability on water softening

    Science.gov (United States)

    Barrera, C.; Arrieta, A.; Escobar, N.; Gañan, P.; Castro, C.

    2013-11-01

    The application of conducting polymer composite for water softening is based on the use of pyrrole's electrochemical properties joined with the flexibility and relatively high surface areas associated with cellulose fibers, to develop a new hybrid material that exhibits the inherent proprieties of both components. This hybrid would allow to promote an ion exchange reaction between the composite membrane and the hard water. The cellulose membranes obtained from banana plant agricultural waste (raquis), were uniform with individual and well separated fibers. The fibers were encapsulated by a continuous coating of polypyrrole by an in situ oxidative chemical polymerization. The amount of polypyrrole deposited on the fiber increased by increasing the monomer concentration, behavior that was identified through the observation of differences on the intensity of the light to dark color shift that coated the fibers after the polymerization. The ion removal capability of the membrane coted with the conducting polymer was tested using an experimental device, finding reductions on the conductivity for hard water within 23 to 66 μs/cm after 6 hours of the assay.

  4. Bacterial Cellulose Membranes Used as Artificial Substitutes for Dural Defection in Rabbits

    Directory of Open Access Journals (Sweden)

    Chen Xu

    2014-06-01

    Full Text Available To improve the efficacy and safety of dural repair in neurosurgical procedures, a new dural material derived from bacterial cellulose (BC was evaluated in a rabbit model with dural defects. We prepared artificial dura mater using bacterial cellulose which was incubated and fermented from Acetobacter xylinum. The dural defects of the rabbit model were repaired with BC membranes. All surgeries were performed under sodium pentobarbital anesthesia, and all efforts were made to minimize suffering. All animals were humanely euthanized by intravenous injection of phenobarbitone, at each time point, after the operation. Then, the histocompatibility and inflammatory effects of BC were examined by histological examination, real-time fluorescent quantitative polymerase chain reaction (PCR and Western Blot. BC membranes evenly covered the surface of brain without adhesion. There were seldom inflammatory cells surrounding the membrane during the early postoperative period. The expression of inflammatory cytokines IL-1β, IL-6 and TNF-α as well as iNOS and COX-2 were lower in the BC group compared to the control group at 7, 14 and 21 days after implantation. BC can repair dural defects in rabbit and has a decreased inflammatory response compared to traditional materials. However, the long-term effects need to be validated in larger animals.

  5. The Use of Cellulose Membrane to Eliminate Burst Release from Intravaginal Rings.

    Science.gov (United States)

    Helbling, Ignacio M; Ibarra, Juan C D; Luna, Julio A

    2016-07-01

    Burst release was observed when ethylene vinyl acetate copolymer (EVA) intravaginal rings were tested for progesterone release in our previous work (Helbling et al. Pharm Res. 31(3):795-808, 2014). Burst release is undesirable in controlled delivery devices because release is uncontrollable and higher levels of active pharmaceutical ingredient could lead to the occurrence of adverse effect. The present contribution is about the use of membranes to coat EVA rings to eliminate burst release. Physicochemical state of progesterone in uncoated rings and the solubility and diffusion coefficient in membrane were studied. Hormone delivery from several rings of different sizes was compared. A mathematical model was used to analyze the effects of membrane properties on delivery rate. No chemical interactions were detected between hormone and polymer. Hormone was mainly forming amorphous aggregates inside rings, and migration to membrane was not observed during storage. Diffusion coefficient was smaller in membrane (∼10(-8) cm(2) s(-1)) than in matrix (∼10(-7) cm(2) s(-1)). Zero-order release kinetics were obtained for coated rings, and release rate decreases as the thickness of the coat increases. Cellulose membrane successfully eliminates burst release and controls the delivery from EVA rings. The equations developed can be used to determine the appropriate coat thickness to produce specific release rate. PMID:27097635

  6. Hydrophilicity and antifouling property of membrane materials from cellulose acetate/polyethersulfone in DMAc.

    Science.gov (United States)

    Sun, Zhonghua; Chen, Fushan

    2016-10-01

    In this study, cellulose acetate (CA) was blended with polyethersulfone (PES) to endow the ultrafiltration membrane with the improved hydrophilicity and antifouling property by using N,N-dimethylacetamide (DMAc) as the solvent. The effects of blend composition and evaporation time on the mechanical strength and pure water flux were investigated. It was found that the optimal composition of the casting solution was: 18wt% (PES), 4wt% (Polyvinylpyrrolidone K30), 3wt% (CA) and 20s (Evaporation time). The characteristics of CA-PES blend membranes were investigated through the methods of contact angle goniometer, antifouling property, compatibility, thermo gravimetric analysis and SEM. The results showed that the hydrophilicity and antifouling property of CA-PES ultrafiltration membranes were enhanced in comparison with the pure PES membranes. The CA-PES membranes exhibited semi-compatibility and good thermal stability below 270°C. This study provided a potential industrial application prospect of CA-PES membranes prepared in DMAc. PMID:27211301

  7. Freestanding bacterial cellulose-graphene oxide composite membranes with high mechanical strength for selective ion permeation.

    Science.gov (United States)

    Fang, Qile; Zhou, Xufeng; Deng, Wei; Zheng, Zhi; Liu, Zhaoping

    2016-01-01

    Graphene oxide (GO) based membranes have been widely applied in molecular separation based on the size exclusion effect of the nanochannels formed by stacked GO sheets. However, it's still a challenge to prepare a freestanding GO-based membrane with high mechanical strength and structural stability which is prerequisite for separation application in aqueous solution. Here, a freestanding composite membrane based on bacterial cellulose (BC) and GO is designed and prepared. BC network provides a porous skeleton to spread GO sheets and uniformly incorporates into the GO layers, which endows the BC + GO composite membrane with well water-stability, excellent tensile strength, as well as improved toughness, guaranteeing its separation applicability in water environment. The resulting BC + GO membrane exhibits obviously discrepant permeation properties for different inorganic/organic ions with different size, and in particular, it can quickly separate ions in nano-scale from angstrom-scale. Therefore, this novel composite membrane is considered to be a promising candidate in the applications of water purification, food industry, biomedicine, and pharmaceutical and fuel separation. PMID:27615451

  8. Preparation of Cellulosic Membrane Containing Pyrrolidone Moiety Via Radiation Induced Grafting and its Application in Wastewater Treatment

    Directory of Open Access Journals (Sweden)

    A. S. Aly

    2005-01-01

    Full Text Available Radiation induced grafting of vinyl pyrrolidone onto cellulose wood pulp was carried out in heterogeneous and homogenous media using gamma radiation. Cellulose wood pulp was used in different forms; a in a homogenous solution by dissolving the wood pulp in N,N- dimethylacetamide/Lithium chloride (DMAc/LiCl mixture , b in a membrane form, by precipitating the cellulose solution in water and c in a powder form. Factors affecting on the grafting such as radiation dose, monomer concentration, precipitator concentration and thickness of the membrane have been studied. The result showed that at the same dose, the grafting yield was higher with cellulose in soluble form than in the membrane form, whereas cellulose in powder exhibited the lowest graft yield. The grafted membrane was characterized by IR, TGA and SEM. The ability of the grafted membrane to remove dyes (acid and basic dye, heavy metal ions (Co 2+ , Ni 2+ and Cu 2+ and phenols from wastewater was also reported.

  9. Control of polyaniline deposition on microporous cellulose ester membranes by in situ chemical polymerization.

    Science.gov (United States)

    Qaiser, Asif A; Hyland, Margaret M; Patterson, Darrell A

    2009-11-12

    Polyaniline (PANI) can be deposited either on the surface or in the bulk of a microporous membrane by various chemical oxidative polymerization techniques. Each technique has distinctive effects on the PANI site and extent of deposition on the base membrane. In the present study, mixed cellulose ester (ME) membranes with tortuous pore morphology were used as base membranes. The chemical oxidative polymerization techniques employed, included polymerization using an in-house-built two-compartment permeation cell. The resultant composite membranes have been characterized by scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR-ATR), and electrical conductivity measurements. The results showed that PANI was layered on the pore walls of the membrane using two-compartment permeation cell. Vapor-phase polymerization yielded a surface layer of PANI with little deposition in the bulk. A distorted PANI surface layer was achieved by solution-phase (dip) polymerization. Moreover, asymmetric PANI deposition within the membrane bulk was evidenced using two-compartment permeation cell. Composite membranes synthesized using two-compartment cell showed highest levels of conductivity (approximately 10(-2) S/cm) as compared to the membranes modified by single-step solution-phase polymerization. FTIR-ATR results indicated the extent of PANI coating and its oxidation state which was identified as doped emeraldine PANI, from all the employed techniques. Asymmetric deposition and extent have been explained in terms of the physical and chemical reaction steps involved in the heterogeneous aniline polymerization reactions in the two-compartment cell technique. PMID:19888765

  10. Long-Term Stability of a Cellulose-Based Glucose Oxidase Membrane

    Directory of Open Access Journals (Sweden)

    Soichi Yabuki

    2014-01-01

    Full Text Available A cellulose-based glucose oxidase membrane was prepared on a glassy carbon (GC electrode. The current response of the electrode to glucose was measured by applying a potential of 1.0 V vs. Ag/AgCl on the base GC and was proportional to the concentration of glucose up to 1 mM. The long-term stability of the electrode was examined by measuring the daily glucose response. Over four months, the response magnitude was maintained and then gradually decreased. After 11 months, though the response magnitude decreased to 50% of the initial value, the linear response range did not change. Therefore, the electrode could be used as a glucose biosensor even after 11 months of use. The entrapment of the enzyme in the cellulose matrix promoted the stability of the enzyme, as revealed by data on the enzyme activity after the enzyme electrode was immersed in urea. Therefore, the cellulose matrix may be used to improve the performance of biosensors, bioreactors and bio-fuel cells.

  11. Nanoporous layered silicate AMH-3/cellulose acetate nanocomposite membranes for gas separations

    KAUST Repository

    Kim, Wun-gwi

    2013-08-01

    Nanoporous layered silicate/polymer composite membranes are of interest because they can exploit the high aspect ratio of exfoliated selective flakes/layers to enhance molecular sieving and create a highly tortuous transport path for the slower molecules. In this work, we combine membrane synthesis, detailed microstructural characterization, and mixed gas permeation measurements to demonstrate that nanoporous flake/polymer membranes allows significant improvement in gas permeability while maintaining selectivity. We begin with the primary-amine-intercalated porous layered silicate SAMH-3 and show that it can be exfoliated using a high shear rate generated by a high-speed mixer. The exfoliated SAMH-3 flakes were used to form SAMH-3/cellulose acetate (CA) membranes. Their microstructure was analyzed by small angle X-ray scattering (SAXS), revealing a high degree of exfoliation of AMH-3 layers in the CA membrane with a small number of layers (4-8) in the exfoliated flakes. TEM analysis visualized the thickness of the flakes as 15-30nm, and is consistent with the SAXS analysis. The CO2/CH4 gas separation performance of the CA membrane was significantly increased by incorporating only 2-6wt% of SAMH-3 flakes. There was a large increase in CO2 permeability with maintenance of selectivity. This cannot be explained by conventional models of transport in flake-containing membranes, and indicates complex transport paths in the membrane. It is also in contrast to the much higher loadings of isotropic particles required for similar enhancements. The present approach may allow avoidance of particle aggregation and poor interfacial adhesion associated with larger quantities of inorganic fillers. © 2013 Elsevier B.V.

  12. Ion Transport across a Polyelectrolyte-Adsorbed Cellulose Triacetate Membrane in the Multicomponent Ionic Systems.

    Science.gov (United States)

    Murata; Tanioka

    1999-01-15

    The effects of polyelectrolyte adsorption by cellulose triacetate (CTA) membrane on ionic transport are investigated in two systems: the three-ionic-component system and the multicomponent-ionic system. In the three-ionic-component system, the permeabilities of two anions are affected by the competitive ion. Especially in the case of the albumin-adsorbed CTA membrane, there exists much greater specificity for the permeability of SO2-4 than in the case of the lysozyme-adsorbed membrane. On the other hand, in the case of the PAS-H(10L)(polydiallyldimethylammonium chloride)-adsorbed membrane, the permeability coefficient of HPO2-4 increases, though there exists the effect of a competitive ion. In a multicomponent-ionic system, the logarithmic permeability coefficient ratios (rP) of each ion in an adsorbed membrane to that in a nonadsorbed membrane decreased by PAS-H(10L) adsorption for all cations. The rP of bivalent cations decreased more than those of univalent cations because of the rejection from the positively charged adsorbed layer. On the other hand, the permeabilities slightly increase because of the attraction from the PAS-H(10L)-adsorbed layer when competitive anions exist among them. Furthermore, the increase in the HPO2-4 permeability is confirmed by PAS-H(10L)-adsorption on a CTA membrane for a case very similar to the actual anion multicomponent system. These are the most important results in the application for an approach to phosphate extraction from blood across an artificial kidney membrane. Copyright 1999 Academic Press. PMID:9885263

  13. Porous thin film barrier layers from 2,3-dicarboxylic acid cellulose nanofibrils for membrane structures.

    Science.gov (United States)

    Visanko, Miikka; Liimatainen, Henrikki; Sirviö, Juho Antti; Haapala, Antti; Sliz, Rafal; Niinimäki, Jouko; Hormi, Osmo

    2014-02-15

    To fabricate a strong hydrophilic barrier layer for ultrafiltration (UF) membranes, 2,3-dicarboxylic acid cellulose nanofibrils with high anionic surface charge density (1.2 mekv/g at pH 7) and a width of 22 ± 4 nm were used. A simple vacuum filtration method combined with a solvent exchange procedure resulted in a porous layer with a thickness of ∼ 0.85 μm. The fabricated membranes reached high rejection efficiencies (74-80%) when aqueous dextrans up to 35-45 kDa were filtrated to evaluate the molecular weight cut-offs (MWCO). A linear correlation between the barrier layer thickness and the flux rate was observed in all tested cases. Further optimization of the barrier layer thickness can lead to an even more effective structure. PMID:24507322

  14. Cellulose acetate electrospun nanofibrous membrane: fabrication, characterization, drug loading and antibacterial properties

    Indian Academy of Sciences (India)

    NAZNIN SULTANA; ANISAH ZAINAL

    2016-04-01

    Cellulose-based materials are one of the most commonly used materials for biomedical applications, which normally applied as carriers for pharmaceuticals and drug-releasing scaffolds. In this study, cellulose acetate (CA) was used to fabricate the nanofibrous membrane using the electrospinning technique. CA solutions at different concentrations were prepared by dissolving the polymer in a mixture of acetic acid/acetone solvents with the ratio of 3:1. The field emission scanning electron microscope results showed that electrospinning of 10% (w/v) CA produced nanofibres with many beads. When the CA concentration was increased to 14% (w/v), bead-free nanofibres were produced. The contact angle measurement results confirmed the hydrophilic properties of nanofibres. In order to prevent common bacterial infections, a model drug, Tetracycline · HCL was incorporated into the CA nanofibres. The drug-loaded CA nanofibres showed antibacterial activity against Gram-positive and Gram-negative bacteria.CA nanofibres had high water uptake properties. The CA nanofibrous membrane was non-toxic to human skin fibroblast cells. Thus the CA nanofibres with 14% (w/v) concentration exerted suitable properties for wound healingapplication.

  15. Electromotive force and impedance studies of cellulose acetate membranes: Evidence for two binding sites for divalent cations and for an alveolar structure of the skin layer

    DEFF Research Database (Denmark)

    Smith Sørensen, T.; Jensen, J.B.; Malmgren-Hansen, B.

    1991-01-01

    The electromotive force (EMF) has been measured for a great number of concentration cells of the type: Ag \\ AgCl \\ >>variableCellulose Acetate Membrane \\ >>fixed...Cellulose Acetate (CA) membranes were mostly dense membranes cast by ourselves. A few were...... asymmetic membranes. The skin layer in asymmetric membranes is assumed to have properties similar to dense membranes. The EMF measurements were interpreted by means of a Donnan-Nernst-Planck (Teorell-Meyer-Sievers) model, which functions quite well due to the low fixed charge in the membrane. The membrane...

  16. Adsorptive removal of phenolic compounds using cellulose acetate phthalate–alumina nanoparticle mixed matrix membrane

    International Nuclear Information System (INIS)

    Highlights: • Composite membrane of cellulose–acetate–phthalate and alumina nanoparticle is cast. • Surface charge of the membrane changes with nanoparticle concentration and pH. • Separation of phenolic compounds occurs due to adsorption. • The removal efficiency is maximum for 20% nanoparticle with 91% removal of catechol. • Transmembrane pressure drop has negligible effect on solute separation. -- Abstract: Mixed matrix membranes (MMMs) were prepared using alumina nanoparticles and cellulose acetate phthalate (CAP) by varying concentration of nanoparticles in the range of 10 to 25 wt%. The membranes were characterized by scanning electron micrograph, porosity, permeability, molecular weight cut off, contact angle, surface zeta potential, mechanical strength. Addition of nanoparticles increased the porosity, permeability of the membrane up to 20 wt% of alumina. pH at point of zero charge of the membrane was 5.4. Zeta potential of the membrane became more negative up to 20 wt% of nanoparticles. Adsorption of phenolic derivatives, catechol, paranitrophenol, phenol, orthochloro phenol, metanitrophenol, by MMMs were investigated. Variation of rejection and permeate flux profiles were studied for different solutes as a function of various operating conditions, namely, solution pH, solute concentration in feed and transmembrane pressure drop. Difference in rejection of phenolic derivatives is consequence of interplay of surface charge and adsorption by alumina. Adsorption isotherm was fitted for different solutes and effects of pH were investigated. Catechol showed the maximum rejection 91% at solution pH 9. Addition of electrolyte reduced the rejection of solutes. Transmembrane pressure drop has insignificant effects on solute rejection. Competitive adsorption reduced the rejection of individual solute

  17. Adsorptive removal of phenolic compounds using cellulose acetate phthalate–alumina nanoparticle mixed matrix membrane

    Energy Technology Data Exchange (ETDEWEB)

    Mukherjee, Raka; De, Sirshendu, E-mail: sde@che.iitkgp.ernet.in

    2014-01-30

    Highlights: • Composite membrane of cellulose–acetate–phthalate and alumina nanoparticle is cast. • Surface charge of the membrane changes with nanoparticle concentration and pH. • Separation of phenolic compounds occurs due to adsorption. • The removal efficiency is maximum for 20% nanoparticle with 91% removal of catechol. • Transmembrane pressure drop has negligible effect on solute separation. -- Abstract: Mixed matrix membranes (MMMs) were prepared using alumina nanoparticles and cellulose acetate phthalate (CAP) by varying concentration of nanoparticles in the range of 10 to 25 wt%. The membranes were characterized by scanning electron micrograph, porosity, permeability, molecular weight cut off, contact angle, surface zeta potential, mechanical strength. Addition of nanoparticles increased the porosity, permeability of the membrane up to 20 wt% of alumina. pH at point of zero charge of the membrane was 5.4. Zeta potential of the membrane became more negative up to 20 wt% of nanoparticles. Adsorption of phenolic derivatives, catechol, paranitrophenol, phenol, orthochloro phenol, metanitrophenol, by MMMs were investigated. Variation of rejection and permeate flux profiles were studied for different solutes as a function of various operating conditions, namely, solution pH, solute concentration in feed and transmembrane pressure drop. Difference in rejection of phenolic derivatives is consequence of interplay of surface charge and adsorption by alumina. Adsorption isotherm was fitted for different solutes and effects of pH were investigated. Catechol showed the maximum rejection 91% at solution pH 9. Addition of electrolyte reduced the rejection of solutes. Transmembrane pressure drop has insignificant effects on solute rejection. Competitive adsorption reduced the rejection of individual solute.

  18. Impact of a silver layer on the membrane of tap water filters on the microbiological quality of filtered water

    OpenAIRE

    Bruderek Juliane; Sohr Dorit; Vonberg Ralf-Peter; Gastmeier Petra

    2008-01-01

    Abstract Background Bacteria in the hospital's drinking water system represent a risk for the acquisition of a nosocomial infection in the severely immunocompromised host. Terminal tap water filters may be used to prevent nosocomial Legionnaires' disease. We present data from water samples using an improved kind of tap water filters. Methods In a blinded study on an intermediate care unit of the thoracic surgery department, a modified type of the Germlyser water filter (Aqua-Free Membrane Tec...

  19. Comparison of biofouling mechanisms between cellulose triacetate (CTA) and thin-film composite (TFC) polyamide forward osmosis membranes in osmotic membrane bioreactors.

    Science.gov (United States)

    Wang, Xinhua; Zhao, Yanxiao; Yuan, Bo; Wang, Zhiwei; Li, Xiufen; Ren, Yueping

    2016-02-01

    There are two types of popular forward osmosis (FO) membrane materials applied for researches on FO process, cellulose triacetate (CTA) and thin film composite (TFC) polyamide. However, performance and fouling mechanisms of commercial TFC FO membrane in osmotic membrane bioreactors (OMBRs) are still unknown. In current study, its biofouling behaviors in OMBRs were investigated and further compared to the CTA FO membrane. The results indicated that β-D-glucopyranose polysaccharides and microorganisms accounted for approximately 77% of total biovolume on the CTA FO membrane while β-D-glucopyranose polysaccharides (biovolume ratio of 81.1%) were the only dominant biofoulants on the TFC FO membrane. The analyses on the biofouling structure implied that a tighter biofouling layer with a larger biovolume was formed on the CTA FO membrane. The differences in biofouling behaviors including biofoulants composition and biofouling structure between CTA and TFC FO membranes were attributed to different membrane surface properties. PMID:26700758

  20. Radiological results for samples collected on paired glass- and cellulose-fiber filters at the Sandia complex, Tonopah Test Range, Nevada

    Energy Technology Data Exchange (ETDEWEB)

    Mizell, Steve A. [Desert Research Inst. (DRI), Las Vegas, NV (United States); Shadel, Craig A. [Desert Research Inst. (DRI), Las Vegas, NV (United States)

    2016-03-01

    Airborne particulates are collected at U.S. Department of Energy sites that exhibit radiological contamination on the soil surface to help assess the potential for wind to transport radionuclides from the contamination sites. Collecting these samples was originally accomplished by drawing air through a cellulose-fiber filter. These filters were replaced with glass-fiber filters in March 2011. Airborne particulates were collected side by side on the two filter materials between May 2013 and May 2014. Comparisons of the sample mass and the radioactivity determinations for the side-by-side samples were undertaken to determine if the change in the filter medium produced significant results. The differences in the results obtained using the two filter types were assessed visually by evaluating the time series and correlation plots and statistically by conducting a nonparametric matched-pair sign test. Generally, the glass-fiber filters collect larger samples of particulates and produce higher radioactivity values for the gross alpha, gross beta, and gamma spectroscopy analyses. However, the correlation between the radioanalytical results for the glass-fiber filters and the cellulose-fiber filters was not strong enough to generate a linear regression function to estimate the glass-fiber filter sample results from the cellulose-fiber filter sample results.

  1. Radiological results for samples collected on paired glass- and cellulose-fiber filters at the Sandia complex, Tonopah Test Range, Nevada

    International Nuclear Information System (INIS)

    Airborne particulates are collected at U.S. Department of Energy sites that exhibit radiological contamination on the soil surface to help assess the potential for wind to transport radionuclides from the contamination sites. Collecting these samples was originally accomplished by drawing air through a cellulose-fiber filter. These filters were replaced with glass-fiber filters in March 2011. Airborne particulates were collected side by side on the two filter materials between May 2013 and May 2014. Comparisons of the sample mass and the radioactivity determinations for the side-by-side samples were undertaken to determine if the change in the filter medium produced significant results. The differences in the results obtained using the two filter types were assessed visually by evaluating the time series and correlation plots and statistically by conducting a nonparametric matched-pair sign test. Generally, the glass-fiber filters collect larger samples of particulates and produce higher radioactivity values for the gross alpha, gross beta, and gamma spectroscopy analyses. However, the correlation between the radioanalytical results for the glass-fiber filters and the cellulose-fiber filters was not strong enough to generate a linear regression function to estimate the glass-fiber filter sample results from the cellulose-fiber filter sample results.

  2. Impact of a silver layer on the membrane of tap water filters on the microbiological quality of filtered water

    Directory of Open Access Journals (Sweden)

    Bruderek Juliane

    2008-10-01

    Full Text Available Abstract Background Bacteria in the hospital's drinking water system represent a risk for the acquisition of a nosocomial infection in the severely immunocompromised host. Terminal tap water filters may be used to prevent nosocomial Legionnaires' disease. We present data from water samples using an improved kind of tap water filters. Methods In a blinded study on an intermediate care unit of the thoracic surgery department, a modified type of the Germlyser water filter (Aqua-Free Membrane Technology with a newly-introduced silver layer on the filtration membrane was compared to its preceding type without such a layer on 15 water outlets. We determined growth of Legionella, other pathogenic bacteria, and the total heterotrophic plate count in unfiltered water and filtered water samples after filter usage intervals of 1 through 4 weeks. Results A total of 299 water samples were tested. Twenty-nine of the 60 unfiltered water samples contained Legionella of various serogroups (baseline value. In contrast, all samples filtered by the original water filter and all but one of the water samples filtered by the modified filter type remained Legionella-free. No other pathogenic bacteria were detected in any filtered sample. The total plate count in water samples increased during use of both kinds of filters over time. However, for the first 7 days of use, there were significantly fewer water samples containing >100 CFU per mL when using the new filter device compared with the older filters or taps with no filter. No advantage was seen thereafter. Conclusion The use of this type of terminal water filter is an appropriate method to protect immunocompromised patients from water-borne pathogens such as Legionella.

  3. An Outer Membrane Protein Involved in the Uptake of Glucose Is Essential for Cytophaga hutchinsonii Cellulose Utilization.

    Science.gov (United States)

    Zhou, Hong; Wang, Xia; Yang, Tengteng; Zhang, Weixin; Chen, Guanjun; Liu, Weifeng

    2016-03-01

    Cytophaga hutchinsonii specializes in cellulose digestion by employing a collection of novel cell-associated proteins. Here, we identified a novel gene locus, CHU_1276, that is essential for C. hutchinsonii cellulose utilization. Disruption of CHU_1276 in C. hutchinsonii resulted in complete deficiency in cellulose degradation, as well as compromised assimilation of cellobiose or glucose at a low concentration. Further analysis showed that CHU_1276 was an outer membrane protein that could be induced by cellulose and low concentrations of glucose. Transcriptional profiling revealed that CHU_1276 exerted a profound effect on the genome-wide response to both glucose and Avicel and that the mutant lacking CHU_1276 displayed expression profiles very different from those of the wild-type strain under different culture conditions. Specifically, comparison of their transcriptional responses to cellulose led to the identification of a gene set potentially regulated by CHU_1276. These results suggest that CHU_1276 plays an essential role in cellulose utilization, probably by coordinating the extracellular hydrolysis of cellulose substrate with the intracellular uptake of the hydrolysis product in C. hutchinsonii. PMID:26773084

  4. Electrochemical Characterization of Cellulose Acetate Butyrate-Prmutit Composite Membrane in Aqueous Uni-Uni Valent Electrolyte Solutions

    Directory of Open Access Journals (Sweden)

    A.K. Tiwari

    2015-06-01

    Full Text Available Co-mixed cellulose acetate butyrate and permutit in a definite composition was prepared and coded as MRS-2. The membrane potential was measured with uni-uni valent electrolyte, NaCl solutions using saturated calomel electrodes (SCEs.The effective fixed charge density of the membrane was determined by TMS method and it showed dependence on the porosity, charge on the membrane matrix, charge and size of permeating ions. Other important electrochemical parameters were calculated. Conductance-time data were generated for the kinetic study of the permeating ions in terms of membrane permeability, flow and flux parameters. Donnan membrane equilibrium condition was examined. Membrane adsorbability showed concave dependence with external electrolyte solution and convex type dependence was showed by swelling and conductance parameters. This membrane had no characteristic of anomalous osmosis, indicates that there is no water flooding will take place during membrane operation.

  5. Novel cellulose ester substrates for high performance flat-sheet thin-film composite (TFC) forward osmosis (FO) membranes

    KAUST Repository

    Ong, Rui Chin

    2015-01-01

    A novel hydrophilic cellulose ester with a high intrinsic water permeability and a water partition coefficient was discovered to construct membrane supports for flat-sheet thin film composite (TFC) forward osmosis (FO) membranes for water reuse and seawater desalination with high performance. The performance of TFC-FO membranes prepared from the hydrophilic cellulose ester containing a high degree of OH and a moderate degree of Pr substitutions clearly surpasses those prepared from cellulose esters and other polymers with moderate hydrophilicity. Post-treatments of TFC-FO membranes using sodium dodecyl sulfate (SDS) and glycerol followed by heat treatment further enhance the water flux without compromising the selectivity. Positron annihilation lifetime analyses have confirmed that the SDS/glycerol post-treatment increases the free volume size and fractional free volume of the polyamide selective layer. The newly developed post-treated TFC-FO membranes exhibit a remarkably high water flux up to 90 LMH when the selective layer is oriented towards the draw solution (i.e., PRO mode) using 1. M NaCl as the draw solution and DI water as the feed. For seawater desalination, the membranes display a high water flux up to 35 LMH using a 2. M NaCl draw solution. These water fluxes exceeded the water fluxes achieved by other types of FO membranes reported in literatures. © 2014 Elsevier B.V.

  6. Cellulose nanofibers decorated with magnetic nanoparticles : synthesis, structure and use in magnetized high toughness membranes for a prototype loudspeaker

    OpenAIRE

    Galland, Sylvain; Andersson, Richard; Salajkova, Michaela; Ström, Valter; Olsson, Richard; Berglund, Lars

    2013-01-01

    Magnetic nanoparticles are the functional component for magnetic membranes, but they are difficult to disperse and process into tough membranes. Here, cellulose nanofibers are decorated with magnetic ferrite nanoparticles formed in situ which ensures a uniform particle distribution, thereby avoiding the traditional mixing stage with the potential risk of particle agglomeration. The attachment of the particles to the nanofibrils is achieved via aqueous in situ hydrolysis of metal precursors on...

  7. Cellulose Acetate Membrane with Improved Perm-selectivity through Modification Dope Composition and Solvent Evaporation for Water Softening

    Directory of Open Access Journals (Sweden)

    T.D. Kusworo

    2014-05-01

    Full Text Available Membrane technology has been developed because applicated on several fields. Hence, in this study carried the production of cellulose acetate nano-filtration membranes for water softening. The main objective of this study was determined the effect of solvent evaporation time and the effect of adding PEG to the morphology and perm-selectivity of asymmetry membrane for water treatment. Membranes prepared by dry/wet phase inversion method with variation of solvent evaporation time of 10-15 sec and addition of 2.5-5 wt% PEG in the dope solution. Membrane characterization consists of calculation of membrane flux and rejection with brackish water as a feed, SEM and FTIR analysis. The research concluded that asymmetric cellulose acetate membrane can be made by dry/wet phase inversion method. The results of FTIR analysis showed the larger absorption peaks indicates that the increasing concentrations of PEG addition make the PEG molecular weight and the unit re-CH2-CH2 O-greater. The results of SEM analysis exhibited that all the membranes are formed has an asymmetric structure consisting of a thin fine porous structure selective barrier and sub-structure of the porous layer is thicker. Moreover, the addition of PEG, the larger pore of membrane will be formed. Performance optimum membrane was obtained on the composition of 23 wt% cellulose acetate, polyethylene-glycol 5 wt%, 72 wt% acetone and 1 wt% of distilled water in the solvent evaporation time of 25 sec and temperature coagulant at room temperature. Characterization of the optimum membrane were flux 22.33 L/m2/h/bar, 92% rejection for turbidity, rejection for dissolved solids 85 and 81% rejection for ions Ca2+, with modulus young around 12433 N/cm2, respectively.

  8. Flexible conductive polypyrrole nanocomposite membranes based on bacterial cellulose with amphiphobicity.

    Science.gov (United States)

    Tang, Lian; Han, Jinlu; Jiang, Zhenlin; Chen, Shiyan; Wang, Huaping

    2015-03-01

    Flexible conductive polypyrrole nanocomposite membranes based on bacterial cellulose (BC) with amphiphobicity have been successfully prepared through in situ chemical synthesis and then infiltrated with polysiloxane solution. The results suggested that polypyrrole (PPy) nanoparticles deposited on the surface of BC formed a continuous core-shell structure by taking along the BC template. After modification with polysiloxane, the surface characteristics of the conductive BC membranes changed from highly hydrophilic to hydrophobic. The AFM images revealed that the roughness of samples after polysiloxane treatment increased along with the increase of pyrrole concentration. The contact angles (CAs) data revealed that the highest water contact angle and highest oil contact angle are 160.3° and 136.7°, respectively. The conductivity of the amphiphobic membranes with excellent flexibility reached 0.32 S/cm and demonstrated a good electromagnetic shielding effectiveness with an SE of 15 dB which could be applied in electromagnetic shielding materials with self-cleaning properties. It opened a new field of potential applications of BC materials. PMID:25498630

  9. Cellulose nanocrystal-filled poly(acrylic acid) nanocomposite fibrous membranes

    Science.gov (United States)

    Lu, Ping; Hsieh, You-Lo

    2009-10-01

    Nanocomposite fibrous membranes have been fabricated by electrospinning cellulose nanocrystal (CNC)-loaded poly(acrylic acid) (PAA) ethanol mixtures. Incorporating CNC in PAA significantly reduced fiber diameters and improved fiber uniformity. The average diameters of the as-spun nanocomposite fibers were significantly reduced from 349 nm to 162 nm, 141 nm, 90 nm and 69 nm at 5%, 10%, 15% and 20% CNC loading (by weight of a constant 4% PAA solution), respectively. CNC was well dispersed in the fibers as isolated rods oriented along the fiber axis and as spheres in the PAA matrix. The Young modulus and stress of the PAA/CNC nanocomposite fibers were significantly improved with increasing CNC loadings by up to 35-fold and 16-fold, respectively. Heat-induced esterification between the CNC surface hydroxyls and PAA carboxyl groups produced covalent crosslinks at the CNC-PAA interfaces, rendering the nanocomposite fibrous membranes insoluble in water, more thermally stable and far more superior in tensile strength. With 20% CNC, the crosslinked nanocomposite fibrous membrane exhibited a very impressive 77-fold increase in modulus and 58-fold increase in stress.

  10. Cellulose nanocrystal-filled poly(acrylic acid) nanocomposite fibrous membranes

    International Nuclear Information System (INIS)

    Nanocomposite fibrous membranes have been fabricated by electrospinning cellulose nanocrystal (CNC)-loaded poly(acrylic acid) (PAA) ethanol mixtures. Incorporating CNC in PAA significantly reduced fiber diameters and improved fiber uniformity. The average diameters of the as-spun nanocomposite fibers were significantly reduced from 349 nm to 162 nm, 141 nm, 90 nm and 69 nm at 5%, 10%, 15% and 20% CNC loading (by weight of a constant 4% PAA solution), respectively. CNC was well dispersed in the fibers as isolated rods oriented along the fiber axis and as spheres in the PAA matrix. The Young modulus and stress of the PAA/CNC nanocomposite fibers were significantly improved with increasing CNC loadings by up to 35-fold and 16-fold, respectively. Heat-induced esterification between the CNC surface hydroxyls and PAA carboxyl groups produced covalent crosslinks at the CNC-PAA interfaces, rendering the nanocomposite fibrous membranes insoluble in water, more thermally stable and far more superior in tensile strength. With 20% CNC, the crosslinked nanocomposite fibrous membrane exhibited a very impressive 77-fold increase in modulus and 58-fold increase in stress.

  11. Enriched glucose and dextrin mannitol-based media modulates fibroblast behavior on bacterial cellulose membranes

    International Nuclear Information System (INIS)

    Bacterial cellulose (BC) produced by Gluconacetobacter hansenii is a suitable biopolymer for biomedical applications. In order to modulate the properties of BC and expand its use as substrate for tissue engineering mainly in the form of biomembranes, glucose or dextrin were added into a BC fermentation mannitol-based medium (BCGl and BCDe, respectively) under static culture conditions. SEM images showed effects on fiber density and porosity on both sides of the BC membranes. Both enriched media decreased the BET surface area, water holding capacity, and rehydration rate. Fourier transform infrared (attenuated total reflectance mode) spectroscopy (FTIR-ATR) analysis revealed no change in the chemical structure of BC. L929 fibroblast cells were seeded on all BC-based membranes and evaluated in aspects of cell adhesion, proliferation and morphology. BCG1 membranes showed the highest biological performance and hold promise for the use in tissue engineering applications. - Highlights: • Glucose and dextrin were used to modify culture media for BC production. • Microarchitecture of BC was different depending on the enriching agent. • Fibroblasts adhered on the surface of BC modified microarchitectures. • Fibroblasts adhered on glucose modified BC exhibited healthy cell morphology

  12. Enriched glucose and dextrin mannitol-based media modulates fibroblast behavior on bacterial cellulose membranes

    Energy Technology Data Exchange (ETDEWEB)

    Stumpf, Taisa R.; Pértile, Renata A.N. [Integrated Technologies Laboratory, Department of Chemical and Food Engineering (Brazil); Rambo, Carlos R., E-mail: rambo@intelab.ufsc.br [Department of Electrical Engineering, Federal University of Santa Catarina, Florianópolis 88040-900 (Brazil); Porto, Luismar M. [Integrated Technologies Laboratory, Department of Chemical and Food Engineering (Brazil)

    2013-12-01

    Bacterial cellulose (BC) produced by Gluconacetobacter hansenii is a suitable biopolymer for biomedical applications. In order to modulate the properties of BC and expand its use as substrate for tissue engineering mainly in the form of biomembranes, glucose or dextrin were added into a BC fermentation mannitol-based medium (BCGl and BCDe, respectively) under static culture conditions. SEM images showed effects on fiber density and porosity on both sides of the BC membranes. Both enriched media decreased the BET surface area, water holding capacity, and rehydration rate. Fourier transform infrared (attenuated total reflectance mode) spectroscopy (FTIR-ATR) analysis revealed no change in the chemical structure of BC. L929 fibroblast cells were seeded on all BC-based membranes and evaluated in aspects of cell adhesion, proliferation and morphology. BCG1 membranes showed the highest biological performance and hold promise for the use in tissue engineering applications. - Highlights: • Glucose and dextrin were used to modify culture media for BC production. • Microarchitecture of BC was different depending on the enriching agent. • Fibroblasts adhered on the surface of BC modified microarchitectures. • Fibroblasts adhered on glucose modified BC exhibited healthy cell morphology.

  13. A 99Tcm labeled HYNIC peptide 'tracer' libraries on continuous cellulose membrane supports

    International Nuclear Information System (INIS)

    Objective: The interference of bifunctional ligands with activities of small peptides has long been recognized. To solve the problem, the hydrazine-nicotinamide (HYNIC) conjugated peptide 'tracer' libraries were synthesized on a continuous cellulose membrane support and the 99Tcm labeled heat shock protein 70 (HSP70) binding peptides were identified by screening libraries with HSP70. Methods: Octapeptide libraries were prepared by manual spot synthesis. HYNIC peptides were C terminally attached to cellulose via a (β-Ala)2 spacer. For screening, the cellulose membranes were incubated with human HSP70 (or biotin labeled HSP70) after nonspecific blocking. Alkaline phosphatase labeled streptavidin and Ab against HSP70 were used for the detection of HSP70 binding. Human lung cancer cell lines (A549 and H460) were cultured in RPMI1640 medium supplemented with 10% fetal calf serum and antibiotics. For in vivo test, 2 x l05 cells were subcutaneously transplanted into the chest of female nude mice. Results: Quality control of HYNIC peptide libraries was good as carried out by 99Tcm labeling. Because peptide NLLRLTG had high affinity for HSP70 family members, 99Tcm-HYNIC-NLLRLTG was used as the control. Fifteen HYNIC peptides were found with HSP70 binding property. Among them, eight peptides had higher uptake (percentage activity of injection dose pergram of tissue, %ID/g) values than 99Tcm-HYNIC-NLLRLTG in tumor. 99Tcm-HYNIC-QGVLTGTR had the best distribution in tumors. Six hours after injection, the %ID/g values of 99Tcm HYNIC-QGVLTGTR and 99Tcm-HYNIC-NLLRLTG in tumor were (1.15±0.32)% ID/g and (0.75±0.24)% ID/g respectively. In vivo replace studies and heat shock stress of tumors demonstrated that 99Tcm-HYNIC-QGVLTGTR was the HSP70 binding peptide compound, but not 99Tcm-HYNIC-NLLRLTG. Conclusions: The identification of 99Tcm labeled HSP70 binding peptides from HYNIC conjugated octapeptide libraries facilitated the hypothesis of the 'tracer' libraries. The design and

  14. Preparation and properties of PEC nanocomposite membranes with carboxymethyl cellulose and modified silica.

    Science.gov (United States)

    Liu, Tao; An, Quan-Fu; Wang, Xue-San; Zhao, Qiang; Zhu, Bao-Ku; Gao, Cong-Jie

    2014-06-15

    Carboxymethyl cellulose (CMC)-modified silica nanocomposites were prepared via in situ incorporation of modified silica during the ionic complexation between CMC and poly(2-methacryloyloxy ethyl trimethylammonium chloride) (PDMC). Ionic bonds were introduced between the poly(2-acrylamido-2-methylproanesulfonic acid) modified silica (SiO2-PAMPS) and the polyelectrolyte complex (PEC) matrix. The PEC nanocomposites (PECNs) and their membranes (PECNMs) were characterized with Fourier transform-infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), scanning electron microscopy (SEM) and tensile testing. PECNM containing 5 wt.% SiO2-PAMPS showed a tensile strength of 68 MPa and elongation at break of 7.1%, which were 1.9 and 2.6 times as high as those of pristine PEC membranes, respectively. Moreover, the pervaporation performance of as-prepared PECNMs was evaluated with dehydration of 10 wt.% aqueous isopropanol mixtures, and the PECNMs exhibited a flux of 2,400 gm(-2)h(-1) with a high separation factor of 4491 at 70°C. PMID:24721095

  15. Permeation of water as a tool for characterizing the effect of solvent, film thickness and water solubility in cellulose acetate membranes

    OpenAIRE

    Valente, Artur J. M.; Polishchuk, Alexandre Ya.; Burrows, Hugh D.; Lobo, Victor M. M.

    2005-01-01

    Cellulose acetate membranes have been used in many applications; of particular interest are reverse osmosis systems, and as a neutral matrix for incorporation of different polymers (e.g., conducting polymers), inorganic ions (e.g., lanthanides) and organic (e.g., pharmaceutical) compounds. The properties of the new polymers derived from cellulose acetate or blends depend on those of cellulose acetate. This work presents an attempt to find links between thermodynamic and kinetic properties of ...

  16. WATER RETENTION VALUE MEASUREMENTS OF CELLULOSIC MATERIALS USING A CENTRIFUGE TECHNIQUE

    OpenAIRE

    Jinxin Wang; Qingzheng Cheng; Joseph McNeel; Peter Jacobson

    2010-01-01

    A centrifugal method has been modified and applied to the assessment of water retention value (WRV) in cellulosic materials. Microcrystalline cellulose (MCC), small particles/fibrils isolated from MCC using high-pressure homogenizer, and pulp fibers saturated in water were centrifuged at different speeds and times with filter paper and/or a membrane acting as the filter in the WRV measurement setup. As centrifugal speed, time, and filter pore-size increased, lower WRVs were obtained. Smaller ...

  17. Preparation and evaluation of water-in-soybean oil-in-water emulsions by repeated premix membrane emulsification method using cellulose acetate membrane.

    Science.gov (United States)

    Muhamad, Ida Idayu; Quin, Chang Hui; Selvakumaran, Suguna

    2016-04-01

    The purpose of this study was to investigate the preparation of formulated water- in-soybean oil-in-water emulsions by repeated premix membrane emulsification method using a cellulose acetate membrane. The effect of selective membrane emulsification process parameters (concentration of the emulsifiers, number of passes of the emulsions through the membrane and storage temperature) on the properties and stability of the developed emulsions were also investigated. 1, 3, 6, 8-pyrenetetrasulfonic acid tetrasodium salt (PTSA) was used as a hydrophilic model ingredient for the encapsulation of bioactive substances. W/O emulsions with 7 wt% (weight percentage) PGPR displays homogeneous and very fine dispersions, with the median diameter at 0.640 μm. Meanwhile, emulsions prepared by membrane emulsification (fine W/O/W) showed the highest stability at Tween 80 concentrations of 0.5 wt.% (weight percentage). It concluded that at 7 wt.% (weight percentage) PGPR concentration and 0.5 wt.% (weight percentage) Tween 80 concentrations, the most uniform particles with minimum mean size of oil drops (9.926 μm) were obtained after four passes through the membrane. Thus, cellulose acetate membrane can be used for preparing a stable W/O/W emulsions by repeated premix ME due to low cost and relatively easy to handle. PMID:27413211

  18. NMMO prepared cellulose membrane of luffa fiber%NMMO法制备丝瓜络再生纤维膜

    Institute of Scientific and Technical Information of China (English)

    袁波; 王迎; 张剑

    2013-01-01

    NMMO was used to prepare cellulose membrane of luffa fiber and its characters and structure were investigated by SEM,FTIR,XRD and TG.SEM result showed that the luffa membrane has an asymmetrical thin skin layer.The characteristic peak shape of the cellulose membrane was observed by FTIR.X ray diffraction analysis showed that the crystalline modification of cellulose membrane made by NMMO process was cellulose Ⅱ.TG analysis shows that the luffa membrane has good thermal stability and satisfied with application requirement.%采用NMMO工艺制取丝瓜络纤维素膜,并对纤维素膜进行表征.利用扫描电子显微镜(SEM)、红外光谱分析仪(FTIR)、X射线衍射仪(XRD)、热力学分析仪(TG)对丝瓜络纤维膜进行表征.SEM结果显示丝瓜络纤维素膜的厚度非常薄,并且膜的表面非常致密;FTIR光谱图显示丝瓜络纤维素膜的特征峰的形状与丝瓜络纤维的特征峰相似,显示出纤维素特征;XRD曲线图显示丝瓜络纤维素膜的纤维素结晶由纤维素Ⅰ变为纤维素Ⅱ;TG曲线图表明丝瓜络纤维素膜具有良好的热稳定性能,符合应用要求.

  19. Preparation, characterization and thermal studies of polymer inclusion cellulose acetate membrane with calix[4]resorcinarenes as carriers

    Energy Technology Data Exchange (ETDEWEB)

    Benosmane, Nadjib [Laboratoire de Chimie Organique Appliquee (Groupe Heterocycles Associe CRAPC), Faculte de Chimie, Universite des Sciences et de la Technologie Houari Boumediene, BP 32, El-Alia, 16111 Bab-Ezzouar, Alger (Algeria); Guedioura, Bouzid [Division reacteur/Centre de Recherche Nucleaire de Draria, CRND, BP 43 Draria, Alger (Algeria); Hamdi, Safouane Mohammed [Laboratoire de Biochimie-Purpan, Institut Federatif de Biologie, CHU Toulouse 330, avenue de Grande-Bretagne - F-31059 Toulouse Cedex 9 (France); Hamdi, Maamar [Laboratoire de Chimie Organique Appliquee (Groupe Heterocycles Associe CRAPC), Faculte de Chimie, Universite des Sciences et de la Technologie Houari Boumediene, BP 32, El-Alia, 16111 Bab-Ezzouar, Alger (Algeria); Boutemeur, Baya, E-mail: bayakheddis@hotmail.com [Laboratoire de Chimie Organique Appliquee (Groupe Heterocycles Associe CRAPC), Faculte de Chimie, Universite des Sciences et de la Technologie Houari Boumediene, BP 32, El-Alia, 16111 Bab-Ezzouar, Alger (Algeria)

    2010-07-20

    A polymer inclusion membrane (PIM) system with cellulose acetate polymer as support and calix[4]resorcinarenes as carriers has been developed. Special attention was paid to PIM characterization using scanning electron microscopy, Fourier-transform infra-red study, X-ray scattering and thermogravimetric analyses. The efficiency of the membrane transport was optimized as a function of pH, stirring speed, aqueous phases and membrane composition. The results suggested that the transport mechanism is a counter-transport of protons, the mechanism was mainly controlled by the diffusion of the complex formed in the membrane core. Analysis of lead(II) transport through these PIMs was performed. It was found that calix[4]resorcinarenes containing membranes were flexible, resistant and heterogeneous without plasticizer addition.

  20. Preparation, characterization and thermal studies of polymer inclusion cellulose acetate membrane with calix[4]resorcinarenes as carriers

    International Nuclear Information System (INIS)

    A polymer inclusion membrane (PIM) system with cellulose acetate polymer as support and calix[4]resorcinarenes as carriers has been developed. Special attention was paid to PIM characterization using scanning electron microscopy, Fourier-transform infra-red study, X-ray scattering and thermogravimetric analyses. The efficiency of the membrane transport was optimized as a function of pH, stirring speed, aqueous phases and membrane composition. The results suggested that the transport mechanism is a counter-transport of protons, the mechanism was mainly controlled by the diffusion of the complex formed in the membrane core. Analysis of lead(II) transport through these PIMs was performed. It was found that calix[4]resorcinarenes containing membranes were flexible, resistant and heterogeneous without plasticizer addition.

  1. Ultrafiltration performance of PVDF, PES, and cellulose membranes for the treatment of coconut water (Cocos nucifera L.

    Directory of Open Access Journals (Sweden)

    Isabel Cristina do Nascimento Debien

    2013-12-01

    Full Text Available Ultrafiltration (UF inhibits the enzymatic activity which is responsible for color changes of coconut water without the need for heat treatment. In the present study, UF performance in terms of the permeate flux and enzymatic retention of the coconut water was evaluated at laboratory unit (LU and pilot unit (PU. The membranes studied were polyethersulfone 150 kDa (UP150, polyvinylidene fluoride 150 kDa (UV150 and cellulose 30 kDa (UC030. The UP150 membrane showed the best permeate flux. The UC030 membrane showed the lowest flux, but it resulted in 100% enzymatic retention, while the other membranes showed enzymatic retentions between 71 and 85%. The application of the UC030 in the pilot unit (PU resulted in a flux value higher than that obtained in the LU due to the tangential velocity effect. The UC030 membrane has proved adequate for industrial applications.

  2. Standard Practice for Processing Aerospace Liquid Samples for Particulate Contamination Analysis Using Membrane Filters

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2008-01-01

    1.1 This practice covers the processing of liquids in preparation for particulate contamination analysis using membrane filters and is limited only by the liquid-to-membrane filter compatibility. 1.2 The practice covers the procedure for filtering a measured volume of liquid through a membrane filter. When this practice is used, the particulate matter will be randomly distributed on the filter surface for subsequent contamination analysis methods. 1.3 The practice describes procedures to allow handling particles in the size range between 2 and 1000 μm with minimum losses during handling. 1.4 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.

  3. SOLID-PHASE ASSAY FOR THE PHOSPHORYLATION OF PROTEINS BLOTTED ON NITROCELLULOSE MEMBRANE FILTERS

    Science.gov (United States)

    A new procedure for the phosphorylation and assay of phosphoproteins is described. Proteins are solubilized from tissue samples, separated by polyacrylamide gel electrophoresis, transferred onto nitrocellulose membrane filters and the blotted polypeptides are phosphorylated with ...

  4. Chemical factors influencing adsorption of bacteriophage MS2 to membrane filters.

    OpenAIRE

    Farrah, S R

    1982-01-01

    Antichaotropic salts, such as magnesium sulfate, and metal chelators, such as citrate ions, promoted adsorption of bacteriophage MS2 to membrane filters. In contrast, compounds that disrupt hydrophobic interactions, such as chaotropic salts, urea, Tween 80, and ethanol, did not promote adsorption of MS2 to membrane filters and counteracted the ability of magnesium sulfate to promote such adsorption. These results provide evidence that magnesium sulfate promotes the association of MS2 with mem...

  5. Predicting bioavailability of PAHs in field-contaminated soils by passive sampling with triolein embedded cellulose acetate membranes

    International Nuclear Information System (INIS)

    Triolein embedded cellulose acetate membrane (TECAM) was used for passive sampling of the fraction of naphthalene, phenanthrene, pyrene and benzo[a]pyrene in 18 field-contaminated soils. The sampling process of PAHs by TECAM fitted well with a first-order kinetics model and PAHs reached 95% of equilibrium in TECAM within 20 h. Concentrations of PAHs in TECAM (CTECAM) correlated well with the concentrations in soils (r2 = 0.693-0.962, p TECAM and the partition coefficient between TECAM and water (KTECAM-w). After lipid normalization nearly 1:1 relationships were observed between PAH concentrations in TECAMs and earthworms exposed to the soils (r2 = 0.591-0.824, n = 18, p < 0.01). These results suggest that TECAM can be a useful tool to predict bioavailability of PAHs in field-contaminated soils. - Triolein embedded cellulose acetate membranes can be a useful tool to predict bioavailability of PAHs in field-contaminated soils

  6. Improvement on filterability in the aerobic treatment of carboxymethyl cellulose (CMC) wastewater

    OpenAIRE

    Qing Pei Ye; Hui Chen Dong; Ming Zhou Gong; Qin Lu; Qiang Ma Ji

    2014-01-01

    CMC is chemically modified from natural cellulose and widely applied in various industries. CMC wastewater consists mainly of sodium glycolate, sodium chloride and water. With extremely high COD and salinity, high concentration CMC wastewater can’t be biologically treated, but with COD and salinity around 15000 mg/L and 30000 mg/L respectively, low concentration CMC wastewater can be aerobically treated. In a CMC factory, the treatment of low concentration ...

  7. Assessment of the elution of charcoal, cellulose acetate, and other particles from cigarettes with charcoal and activated charcoal/resin filters.

    Science.gov (United States)

    Agyei-Aye, K; Appleton, S; Rogers, R A; Taylor, C R

    2004-08-01

    This experiment was designed to study the release of cellulose acetate fibers, charcoal, and other particles from cigarettes with charcoal and activated charcoal/resin filters. For the first time in such studies, efforts were made to identify the particles that were eluted using other analytical techniques in addition to light microscopy. Other corrective measures were also implemented. During the studies it was found that trimming of larger filters to fit smaller filter housings introduced cellulose acetate-like particles from the fibers of the filter material. Special, custom made-to-fit filters were used instead. Tools such as forceps that were used to retrieve filters from their housings were also found to introduce fragments onto the filters. It is believed that introduction of such debris may have accounted for the very large number of cellulose acetate and charcoal particles that had been reported in the literature. Use of computerized particle-counting microscopes appeared to result in excessive number of particles. This could be because the filter or smoke pads used for such work do not have the flat and level surfaces ideal for computerized particle-counting microscopes. At the high magnifications that the pads were viewed for particles, constant focusing of the microscope would be essential. It was also found that determination of total particles by using extrapolation of particle count by grid population usually gave extremely high particle counts compared to the actual number of particles present. This could be because particle distributions during smoking are not uniform. Lastly, a less complex estimation of the thickness of the particles was adopted. This and the use of a simple mathematical conversion coupled with the Cox equation were utilized to assess the aerodynamic diameters of the particles. Our findings showed that compared to numbers quoted in the literature, only a small amount of charcoal, cellulose acetate shards, and other particles are

  8. Eggshell and Bacterial Cellulose Composite Membrane as Absorbent Material in Active Packaging

    OpenAIRE

    Ummartyotin, S.; Pisitsak, P.; Pechyen, C.

    2016-01-01

    Bacterial cellulose and eggshell composite was successfully developed. Eggshell was mixed with bacterial cellulose suspension and it was casted as a composite film. CaCO3 derived from eggshell was compared with its commercial availability. It can be noted that good dispersion of eggshell particle was prepared. Eggshell particle was irregular in shape with a variation in size. It existed in bacterial cellulose network. Characterization on composite was focused on thermal and mechanical propert...

  9. Structural, chemical surface and transport modifications of regenerated cellulose dense membranes due to low-dose {gamma}-radiation

    Energy Technology Data Exchange (ETDEWEB)

    Vazquez, M.I. [Grupo de Caracterizacion Electrocinetica en Membranas e Interfases, Departamento de Fisica Aplicada I, Facultad de Ciencias, Universidad de Malaga, E-29071 Malaga (Spain); Heredia-Guerrero, J.A., E-mail: jose.alejandro@icmse.csic.es [Instituto de Ciencia de Materiales de Sevilla, Centro Mixto CSIC-Universidad de Sevilla, Avda, Americo Vespuccio 49, 41092 Sevilla (Spain); Galan, P. [Grupo de Caracterizacion Electrocinetica en Membranas e Interfases, Departamento de Fisica Aplicada I, Facultad de Ciencias, Universidad de Malaga, E-29071 Malaga (Spain); Benitez, J.J. [Instituto de Ciencia de Materiales de Sevilla, Centro Mixto CSIC-Universidad de Sevilla, Avda, Americo Vespuccio 49, 41092 Sevilla (Spain); Benavente, J. [Grupo de Caracterizacion Electrocinetica en Membranas e Interfases, Departamento de Fisica Aplicada I, Facultad de Ciencias, Universidad de Malaga, E-29071 Malaga (Spain)

    2011-04-15

    Research highlights: {yields} Low dose {gamma}-radiation causes slight structural, chemical and morphological changes on regenerated cellulose films. {yields} Induced structural changes increase the fragility of irradiated films. {yields} Structural modifications reduce ion permeability of films. - Abstract: Modifications caused in commercial dense regenerated cellulose (RC) flat membranes by low-dose {gamma}-irradiation (average photons energy of 1.23 MeV) are studied. Slight structural, chemical and morphological surface changes due to irradiation in three films with different RC content were determined by ATR-FTIR, XRD, XPS and AFM. Also, the alteration of their mechanical elasticity has been studied. Modification of membrane performance was determined from solute diffusion coefficient and effective membrane fixed charge concentration obtained from NaCl diffusion measurements. Induced structural changes defining new and effective fracture propagation directions are considered to be responsible for the increase of fragility of irradiated RC membranes. The same structural changes are proposed to explain the reduction of the membrane ion permeability through a mechanism involving either ion pathways elongation and/or blocking.

  10. Structural, chemical surface and transport modifications of regenerated cellulose dense membranes due to low-dose γ-radiation

    International Nuclear Information System (INIS)

    Research highlights: → Low dose γ-radiation causes slight structural, chemical and morphological changes on regenerated cellulose films. → Induced structural changes increase the fragility of irradiated films. → Structural modifications reduce ion permeability of films. - Abstract: Modifications caused in commercial dense regenerated cellulose (RC) flat membranes by low-dose γ-irradiation (average photons energy of 1.23 MeV) are studied. Slight structural, chemical and morphological surface changes due to irradiation in three films with different RC content were determined by ATR-FTIR, XRD, XPS and AFM. Also, the alteration of their mechanical elasticity has been studied. Modification of membrane performance was determined from solute diffusion coefficient and effective membrane fixed charge concentration obtained from NaCl diffusion measurements. Induced structural changes defining new and effective fracture propagation directions are considered to be responsible for the increase of fragility of irradiated RC membranes. The same structural changes are proposed to explain the reduction of the membrane ion permeability through a mechanism involving either ion pathways elongation and/or blocking.

  11. A composite membrane based on a biocompatible cellulose as a host of gel polymer electrolyte for lithium ion batteries

    Science.gov (United States)

    Xiao, S. Y.; Yang, Y. Q.; Li, M. X.; Wang, F. X.; Chang, Z.; Wu, Y. P.; Liu, X.

    2014-12-01

    A composite polymer membrane is prepared by coating poly(vinylidene fluoride) (PVDF) on the surface of a membrane based on methyl cellulose (MC) which is environmentally friendly and cheap. Its characteristics are investigated by scanning electron microscopy, FT-IR, thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The outer PVDF layers are porous which results in high electrolyte uptake and the lithium ion transference number is much larger than that of the pure MC. Moreover, the cell based on Li//LiFePO4 delivers high discharge capacity and good rate behavior in the range of 4.2-2.5 V when the composite membrane is used as the separator and the host of a gel polymer electrolyte, lithium as the counter and reference electrode, and LiFePO4 as cathode. The obtained results suggest that this unique composite membrane shows great attraction in the lithium ion batteries with high safety and low cost.

  12. Cellulose synthase interacting protein: A new factor in cellulose synthesis

    OpenAIRE

    Gu, Ying; Somerville, Chris

    2010-01-01

    Cellulose is the most abundant biopolymer on earth. The great abundance of cellulose places it at the forefront as a primary source of biomass for renewable biofuels. However, the knowledge of how plant cells make cellulose remains very rudimentary. Cellulose microfibrils are synthesized at the plasma membrane by hexameric protein complexes, also known as cellulose synthase complexes. The only known components of cellulose synthase complexes are cellulose synthase (CESA) proteins until the re...

  13. Membrane water deaerator investigation. [fluid filter breadboard model

    Science.gov (United States)

    Elam, J.; Ruder, J.; Strumpf, H.

    1974-01-01

    The purpose of the membrane water deaerator program was to develop data on a breadboard hollow fiber membrane unit that removes both dissolved and evolved gas from a water transfer system in order to: (1) assure a hard fill of the EVLSS expendable water tank; (2) prevent flow blockage by gas bubbles in circulating systems; and (3) prevent pump cavitation.

  14. Well-constructed cellulose acetate membranes for forward osmosis: Minimized internal concentration polarization with an ultra-thin selective layer

    KAUST Repository

    Zhang, Sui

    2010-09-01

    The design and engineering of membrane structure that produces low salt leakage and minimized internal concentration polarization (ICP) in forward osmosis (FO) processes have been explored in this work. The fundamentals of phase inversion of cellulose acetate (CA) regarding the formation of an ultra-thin selective layer at the bottom interface of polymer and casting substrate were investigated by using substrates with different hydrophilicity. An in-depth understanding of membrane structure and pore size distribution has been elucidated with field emission scanning electronic microscopy (FESEM) and positron annihilation spectroscopy (PAS). A double dense-layer structure is formed when glass plate is used as the casting substrate and water as the coagulant. The thickness of the ultra-thin bottom layer resulted from hydrophilic-hydrophilic interaction is identified to be around 95nm, while a fully porous, open-cell structure is formed in the middle support layer due to spinodal decomposition. Consequently, the membrane shows low salt leakage with mitigated ICP in the FO process for seawater desalination. The structural parameter (St) of the membrane is analyzed by modeling water flux using the theory that considers both external concentration polarization (ECP) and ICP, and the St value of the double dense-layer membrane is much smaller than those reported in literatures. Furthermore, the effects of an intermediate immersion into a solvent/water mixed bath prior to complete immersion in water on membrane formation have been studied. The resultant membranes may have a single dense layer with an even lower St value. A comparison of fouling behavior in a simple FO-membrane bioreactor (MBR) system is evaluated for these two types of membranes. The double dense-layer membrane shows a less fouling propensity. This study may help pave the way to improve the membrane design for new-generation FO membranes. © 2010 Elsevier B.V.

  15. Membrane Made of Cellulose Acetate with Polyacrylic Acid Reinforced with Carbon Nanotubes and Its Applicability for Chromium Removal

    Directory of Open Access Journals (Sweden)

    J. A. Sánchez-Márquez

    2015-01-01

    Full Text Available Membranes made of carbon nanotubes and cellulose acetate with polyacrylic acid were designed in order to study their properties and their applicability for chromium removal. The membranes were prepared by phase inversion method using cellulose acetate and polyacrylic acid. Carbon nanotubes were added to the membrane during their process of synthesis in proportions of 1% by weight. The pores in the material are formed in layers, giving the effect of depth and forming a network. Both the carbon nanotubes and membranes were characterized by IR, Raman, and SEM spectroscopy. In addition, the concentration of acidic and basic sites and the surface charge in the materials were determined. The concentration of acid sites for oxidized nanotubes was 4.0 meq/g. The removal of Cr(VI was studied as a function of contact time and of initial concentration of Cr(VI. The removal of Cr(VI (~90% mainly occurs in a contact time from 32 to 64 h when the initial concentration of Cr(VI is 1 mg/L.

  16. Bacterial cellulose membrane produced by Acetobacter sp. A10 for burn wound dressing applications.

    Science.gov (United States)

    Kwak, Moon Hwa; Kim, Ji Eun; Go, Jun; Koh, Eun Kyoung; Song, Sung Hwa; Son, Hong Joo; Kim, Hye Sung; Yun, Young Hyun; Jung, Young Jin; Hwang, Dae Youn

    2015-05-20

    Bacteria cellulose membranes (BCM) are used for wound dressings, bone grafts, tissue engineering, artificial vessels, and dental implants because of their high tensile strength, crystallinity and water holding ability. In this study, the effects of BCM application for 15 days on healing of burn wounds were investigated based on evaluation of skin regeneration and angiogenesis in burn injury skin of Sprague-Dawley (SD) rats. BCM showed a randomly organized fibrils network, 12.13 MPa tensile strength, 12.53% strain, 17.63% crystallinity, 90.2% gel fraction and 112.14 g × m(2)/h highest water vapor transmission rate (WVTR) although their swelling ratio was enhanced to 350% within 24h. In SD rats with burned skin, the skin severity score was lower in the BCM treated group than the gauze (GZ) group at all time points, while the epidermis and dermis thickness and number of blood vessels was greater in the BCM treated group. Furthermore, a significant decrease in the number of infiltrated mast cells and in vascular endothelial growth factor (VEGF) and angiopoietin-1 (Ang-1) expression was observed in the BCM treated group at day 10 and 15. Moreover, a significant high level in collagen expression was observed in the BCM treated group at day 5 compared with GZ treated group, while low level was detected in the same group at day 10 and 15. However, the level of metabolic enzymes representing liver and kidney toxicity in the serum of BCM treated rats was maintained at levels consistent with GZ treated rats. Overall, BCM may accelerate the process of wound healing in burn injury skin of SD rats through regulation of angiogenesis and connective tissue formation as well as not induce any specific toxicity against the liver and kidney. PMID:25817683

  17. Use of pressure-hold test for sterilizing filter membrane integrity in radiopharmaceutical manufacturing

    International Nuclear Information System (INIS)

    The bubble point test is the de facto standard for postproduction filter membrane integrity test in the radiopharmaceutical community. However, the bubble point test depends on a subjective visual assessment of bubbling rate that can be obscured by significant diffusive gas flows below the manufacturer's prescribed bubble point. To provide a more objective means to assess filter membrane integrity, this study evaluates the pressure-hold test as an alternative to the bubble point test. In our application of the pressure-hold test, the nonsterile side of the sterilizing filter is pressurized to 85% of the predetermined bubble point with nitrogen, the filter system is closed off from the pressurizing gas and the pressure is monitored over a prescribed time interval. The drop in pressure, which has a known relationship with diffusive gas flow, is used as a quantitative measure of membrane integrity. Characterization of the gas flow vs. pressure relationship of each filter/solution combination provides an objective and quantitative means for defining a critical value of pressure drop over which the membrane is indicated to be nonintegral. The method is applied to sterilizing filter integrity testing associated with the commonly produced radiopharmaceuticals, [18F]FDG and [11C]PIB. The method is shown to be robust, practical and amenable to automation in radiopharmaceutical manufacturing environments (e.g., hot cells).

  18. Organic fouling of thin-film composite polyamide and cellulose triacetate forward osmosis membranes by oppositely charged macromolecules.

    Science.gov (United States)

    Gu, Yangshuo; Wang, Yi-Ning; Wei, Jing; Tang, Chuyang Y

    2013-04-01

    Fouling of cellulose triacetate (CTA) and thin-film composite (TFC) forward osmosis (FO) membranes by organic macromolecules were studied using oppositely charged lysozyme (LYS) and alginate (ALG) as model foulants. Flux performance and foulant deposition on membranes were systematically investigated for a submerged membrane system. When an initial flux of 25 L/m(2)h was applied, both flux reduction and foulant mass deposition were severe for feed water containing the mixture of LYS and ALG (e.g., 50% LYS and 50% ALG at a total foulant concentration of 100 mg/L). In comparison, fouling was much milder for feed water containing either LYS or ALG alone. Compared to the CTA FO membrane, the TFC FO membrane showed greater fouling propensity under mild FO fouling conditions due to its much rougher surface. Nevertheless, under severe FO fouling conditions, fouling was dominated by foulant-deposited-foulant interaction and membrane surface properties played a less important role. Furthermore, when the feed water contained both LYS and ALG in sufficient amount, the deposited cake layer foulant composition (i.e., the LYS/ALG mass ratio) was not strongly affected by membrane types (CTA versus TFC) nor testing modes (pressure-driven NF mode versus osmosis-driven FO mode). In contrast, solution chemistry such as pH and calcium concentration had remarkable effect on the cake layer composition due to their effects on foulant-foulant interaction. PMID:23384517

  19. Transport of lanthanide ions through cellulose triacetate membranes containing hinokitiol and flavonol as carriers. [beta-isopropyltropolone and 3-hydroxyflavone

    Energy Technology Data Exchange (ETDEWEB)

    Sugiura, Masaaki (National Chemical Lab. for Industry, Ibaraki (Japan))

    Fluxes of trivalent lanthanide ions across cellulose triacetate membranes were determined by using hinokitiol (HIPT) and flavonol (HFL) as carriers. The transport of the lanthanides was coupled to flow of hydrogen ions. The effects added anion and the pH in the source phase, and the plasticizer incorporated in the membrane on the lanthanide flux, were examined. In the case of HIPT, the fluxes for the lanthanides from samarium to lutetium were much higher than those for lanthanum to neodymium. In the transport using HFL, the flux increased with decreasing ionic radius of the lanthanide species. The addition of perchlorate of thiocyanate ions to the source phase resulted in a rise in the lanthanide flux. With decreased in pH difference between the aqueous phases, the fluxes using HIPT decreased gradually while those using HFL decreased rapidly. The flux was affected by the type of plasticizer added to the membrane.

  20. Membrane metamaterial resonators with a sharp resonance: A comprehensive study towards practical terahertz filters and sensors

    Directory of Open Access Journals (Sweden)

    Yongyao Chen

    2012-06-01

    Full Text Available We investigate the resonant properties of high quality-factor membrane-based metamaterial resonators functioning in the terahertz regime. A number of factors, including the resonator geometry, dielectric loss, and most importantly the membrane thickness are found to extensively influence the resonance strength and quality factor of the sharp resonance. Further studies on the membrane thickness-dependent-sensitivity for sensing applications reveal that high quality-factor membrane metamaterials with a moderate thickness ranging from 10 to 50 μm are the most promising option towards developing realistic integrated terahertz filters and sensors.

  1. Development of Low Cost Membranes (Ta, Nb & Cellulose Acetate) for H2/CO2 Separation in WGS Reactors

    Energy Technology Data Exchange (ETDEWEB)

    Seetala, Naidu [Grambling State Univ., LA (United States); Siriwardane, Upali [Louisiana Tech Univ., Ruston, LA (United States)

    2011-12-15

    The main aim of this work is to synthesize low temperature bimetallic nanocatalysts for Water Gas Shift reaction (WGS) for hydrogen production from CO and steam mixture; and develop low-cost metal (Nb/Ta)/ceramic membranes for H2 separation and Cellulose Acetate membranes for CO2 separation. .

  2. Post-hybridization recovery of membrane filter-bound DNA for enzymatic DNA amplification.

    Science.gov (United States)

    Chong, K Y; Chen, C M; Choo, K B

    1993-04-01

    We describe here a simple and rapid method for enzymatic DNA amplification using DNA template recovered from membrane filters previously used in hybridization analysis. This is done by first solubilizing membrane pieces carrying DNA of interest in dimethyl sulfoxide, followed by isopropanol precipitation and polymerase chain reaction amplification. The source of membrane-bound DNA successfully tested includes plasmid and human leukocyte DNA and DNA immobilized on bacterial colony filters and plaque lifts. The sensitivity of the procedure is such that DNA recovered from 0.5 microgram of filter-bound total human DNA was enough for PCR amplification of a 0.3-kb fragment. Our protocol will be useful for recycling of scarce DNA samples for cloning and sequencing purposes. PMID:8476600

  3. Development of nitrocellulose membrane filters impregnated with different biosynthesized silver nanoparticles applied to water purification.

    Science.gov (United States)

    Fernández, Jorge G; Almeida, César A; Fernández-Baldo, Martín A; Felici, Emiliano; Raba, Julio; Sanz, María I

    2016-01-01

    Bactericidal water filters were developed. For this purpose, nitrocellulose membrane filters were impregnated with different biosynthesized silver nanoparticles. Silver nanoparticles (AgNPs) from Aspergillus niger (AgNPs-Asp), Cryptococcus laurentii (AgNPs-Cry) and Rhodotorula glutinis (AgNPs-Rho) were used for impregnating nitrocellulose filters. The bactericidal properties of these nanoparticles against Escherichia coli, Enterococcus faecalis and Pseudomona aeruginosa were successfully demonstrated. The higher antimicrobial effect was observed for AgNPs-Rho. This fact would be related not only to the smallest particles, but also to polysaccharides groups that surrounding these particles. Moreover, in this study, complete inhibition of bacterial growth was observed on nitrocellulose membrane filters impregnated with 1 mg L(-1) of biosynthesized AgNPs. This concentration was able to reduce the bacteria colony count by over 5 orders of magnitude, doing suitable for a water purification device. PMID:26695258

  4. Cellulose reinforced nylon-6 nanofibrous membrane: Fabrication strategies, physicochemical characterizations, wicking properties and biomimetic mineralization.

    Science.gov (United States)

    Joshi, Mahesh Kumar; Tiwari, Arjun Prasad; Maharjan, Bikendra; Won, Ko Sung; Kim, Han Joo; Park, Chan Hee; Kim, Cheol Sang

    2016-08-20

    The aim of the present study is to develop a facile, efficient approach to reinforce nylon 6 (N6) nanofibers with cellulose chains as well as to study the effect that cellulose regeneration has on the physicochemical properties of the composite fibers. Here, a cellulose acetate (CA) solution (17wt%) was prepared in formic acid and was blended with N6 solution (20%, prepared in formic acid and acetic acid) in various proportions, and the blended solutions were then electrospun to produce hybrid N6/CA nanofibers. Cellulose was regenerated in-situ in the fiber via alkaline saponification of the CA content of the hybrid fiber, leading to cellulose-reinforced N6 (N6/CL) nanofibers. Electron microscopy studies suggest that the fiber diameter and hence pore size gradually decreases as the mass composition of CA increases in the electrospinning solution. Cellulose regeneration showed noticeable change in the polymorphic behavior of N6, as observed in the XRD and IR spectra. The strong interaction of the hydroxyl group of cellulose with amide group of N6, mainly via hydrogen bonding, has a pronounced effect on the polymorphic behavior of N6. The γ-phase was dominant in pristine N6 and N6/CA fibers while α- phase was dominant in the N6/CL fibers. The surface wettability, wicking properties, and the tensile stress were greatly improved for N6/CL fibers compared to the corresponding N6/CA hybrid fibers. Results of DSC/TGA revealed that N6/CL fibers were more thermally stable than pristine N6 and N6/CA nanofibers. Furthermore, regeneration of cellulose chain improved the ability to nucleate bioactive calcium phosphate crystals in a simulated body fluid solution. PMID:27178914

  5. In situ deposition of platinum nanoparticles on bacterial cellulose membranes and evaluation of PEM fuel cell performance

    International Nuclear Information System (INIS)

    In situ deposition of platinum (Pt) nanoparticles on bacterial cellulose membranes (BC) for a fuel cell application was studied. The platinum/bacterial cellulose (Pt/BC) membranes under different experimental conditions were characterized by using SEM (scanning electron microscopy), TEM (transmission electron microscopy), EDS (energy dispersive spectroscopy), XRD (X-ray diffractometry) and TG (thermo-gravimetric analysis) techniques. TEM images and XRD patterns both lead to the observation of spherical metallic platinum nanoparticles with mean diameter of 3-4 nm well impregnated into the BC fibrils. TG curves revealed these Pt/BC composite materials had the high thermal stability. The electrosorption of hydrogen was investigated by CV (cyclic voltammetry). It was found that Pt/BC catalysts have high electrocatalytic activity in the hydrogen oxidation reaction. The single cell performance of Pt/BC was tested at 20 deg. C, 30 deg. C, and 40 deg. C under non-humidified conditions. Preliminary tests on a single cell indicate that renewable BC is a good prospect to be explored as membrane in fuel cell field [B.R. Evans, H.M. O'Neill, V.P. Malyvanh, I. Lee, J. Woodward, Biosens. Bioelectron. 18 (2003) 917].

  6. In situ deposition of platinum nanoparticles on bacterial cellulose membranes and evaluation of PEM fuel cell performance

    Energy Technology Data Exchange (ETDEWEB)

    Yang Jiazhi [School of Chemistry and Chemical Engineering, Nan Jing University of Science and Technology, Nanjing 210094 (China); Sun Dongping [School of Chemistry and Chemical Engineering, Nan Jing University of Science and Technology, Nanjing 210094 (China)], E-mail: dongpingsun@163.com; Li Jun; Yang Xujie; Yu Junwei; Hao Qingli [School of Chemistry and Chemical Engineering, Nan Jing University of Science and Technology, Nanjing 210094 (China); Liu Wenming [Eco-materials and Renewable Energy Research Center, Department of Materials Science and Engineering and National Laboratory of Solid State Microstructures, Nanjing University, Nanjing 210093 (China); Liu Jianguo [Eco-materials and Renewable Energy Research Center, Department of Materials Science and Engineering and National Laboratory of Solid State Microstructures, Nanjing University, Nanjing 210093 (China)], E-mail: jianguoliu@nju.edu.cn; Zou Zhigang; Gu Jun [Eco-materials and Renewable Energy Research Center, Department of Materials Science and Engineering and National Laboratory of Solid State Microstructures, Nanjing University, Nanjing 210093 (China)

    2009-11-01

    In situ deposition of platinum (Pt) nanoparticles on bacterial cellulose membranes (BC) for a fuel cell application was studied. The platinum/bacterial cellulose (Pt/BC) membranes under different experimental conditions were characterized by using SEM (scanning electron microscopy), TEM (transmission electron microscopy), EDS (energy dispersive spectroscopy), XRD (X-ray diffractometry) and TG (thermo-gravimetric analysis) techniques. TEM images and XRD patterns both lead to the observation of spherical metallic platinum nanoparticles with mean diameter of 3-4 nm well impregnated into the BC fibrils. TG curves revealed these Pt/BC composite materials had the high thermal stability. The electrosorption of hydrogen was investigated by CV (cyclic voltammetry). It was found that Pt/BC catalysts have high electrocatalytic activity in the hydrogen oxidation reaction. The single cell performance of Pt/BC was tested at 20 deg. C, 30 deg. C, and 40 deg. C under non-humidified conditions. Preliminary tests on a single cell indicate that renewable BC is a good prospect to be explored as membrane in fuel cell field [B.R. Evans, H.M. O'Neill, V.P. Malyvanh, I. Lee, J. Woodward, Biosens. Bioelectron. 18 (2003) 917].

  7. Neutralized ion beam modification of cellulose membranes for study of ion charge effect on ion-beam-induced DNA transfer

    Energy Technology Data Exchange (ETDEWEB)

    Prakrajang, K., E-mail: k.prakrajang@gmail.com [Plasma and Beam Physics Research Facility, Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Sangwijit, K.; Anuntalabhochai, S. [Molecular Biology Laboratory, Department of Biology, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Wanichapichart, P. [Membrane Science and Technology Research Center, Department of Physics, Faculty of Science, Prince of Songkla University, Hat Yai, Songkla 90110 (Thailand); Thailand Center of Excellence in Physics, Commission on Higher Education, 328 Si Ayutthaya Road, Bangkok 10400 (Thailand); Yu, L.D., E-mail: yuld@fnrf.science.cmu.ac.th [Plasma and Beam Physics Research Facility, Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Thailand Center of Excellence in Physics, Commission on Higher Education, 328 Si Ayutthaya Road, Bangkok 10400 (Thailand)

    2012-02-01

    Low-energy ion beam biotechnology (IBBT) has recently been rapidly developed worldwide. Ion-beam-induced DNA transfer is one of the important applications of IBBT. However, mechanisms involved in this application are not yet well understood. In this study plasma-neutralized ion beam was applied to investigate ion charge effect on induction of DNA transfer. Argon ion beam at 7.5 keV was neutralized by RF-driven plasma in the beam path and then bombarded cellulose membranes which were used as the mimetic plant cell envelope. Electrical properties such as impedance and capacitance of the membranes were measured after the bombardment. An in vitro experiment on plasmid DNA transfer through the cellulose membrane was followed up. The results showed that the ion charge input played an important role in the impedance and capacitance changes which would affect DNA transfer. Generally speaking, neutral particle beam bombardment of biologic cells was more effective in inducing DNA transfer than charged ion beam bombardment.

  8. Gypsum (CaSO42H2O) scaling on polybenzimidazole and cellulose acetate hollow fiber membranes under forward osmosis

    KAUST Repository

    Chen, Si Cong

    2013-11-08

    We have examined the gypsum (CaSO42H2O) scaling phenomena on membranes with different physicochemical properties in forward osmosis (FO) processes. Three hollow fiber membranes made of (1) cellulose acetate (CA), (2) polybenzimidazole (PBI)/polyethersulfone (PES) and (3) PBI-polyhedral oligomeric silsesquioxane (POSS)/polyacrylonitrile (PAN) were studied. For the first time in FO processes, we have found that surface ionic interactions dominate gypsum scaling on the membrane surface. A 70% flux reduction was observed on negatively charged CA and PBI membrane surfaces, due to strong attractive forces. The PBI membrane surface also showed a slightly positive charge at a low pH value of 3 and exhibited a 30% flux reduction. The atomic force microscopy (AFM) force measurements confirmed a strong repulsive force between gypsum and PBI at a pH value of 3. The newly developed PBI-POSS/PAN membrane had ridge morphology and a contact angle of 51.42 14.85 after the addition of hydrophilic POSS nanoparticles and 3 min thermal treatment at 95 C. Minimal scaling and an only 1.3% flux reduction were observed at a pH value of 3. Such a ridge structure may reduce scaling by not providing a locally flat surface to the crystallite at a pH value of 3; thus, gypsum would be easily washed away from the surface. 2013 by the authors; licensee MDPI, Basel, Switzerland.

  9. STUDY OF COMPOSITE MEMBRANE OF CELLULOSE ACETATE OR POLYVINYL ALCOHOL BLENDED WITH METHYLMETHACRYLATE-ACRYLIC ACID COPOLYMER FOR PERVAPORATION SEPARATION

    Institute of Scientific and Technical Information of China (English)

    Huan-lin Chen; Jun Tan; Mo-e Liu; Chang-luo Zhu

    1999-01-01

    In this paper, methylmethacrylate-acrylic acid MMA-AA hydrophilic and hydrophobic copolymers were prepared by copolymerization for preparing membrane materials. The composite membrane of cellulose acetate (CA) blended with MMA-AA hydrophobic copolymer was used for the separation of methanol from pentane-methanol mixture. When the methanol concentration was only 1 wt%, the permeate flux still maintained at 350 g/m2h and separation factor was as big as 800. The composite membrane of PVA (polyvinyl alcohol) blended with MMA-AA hydrophilic copolymer was used for the separation of ethanolwater mixture. The permeate flux was increased to 975 g/m2h at 74℃ and the separation factor reached 3000at 25℃. The PVA/MMA-AA blended membrane surface modified by ammonia plasma was also investigated for separating ethanol-water mixture. Both permeate flux and separation factor of the membrane was improved. However, there was no obvious difference of plasma treatment time in the interval of 20~40 min.

  10. Predicting bioavailability of PAHs in field-contaminated soils by passive sampling with triolein embedded cellulose acetate membranes

    Energy Technology Data Exchange (ETDEWEB)

    Tao Yuqiang [State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, P.O. Box 2871, Beijing 100085 (China); Zhang Shuzhen [State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, P.O. Box 2871, Beijing 100085 (China)], E-mail: szzhang@rcees.ac.cn; Wang Zijian [State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, P.O. Box 2871, Beijing 100085 (China); Christie, Peter [Queen' s University Belfast, Agricultural and Environmental Science Department, Newforge Lane, Belfast BT9 5PX (United Kingdom)

    2009-02-15

    Triolein embedded cellulose acetate membrane (TECAM) was used for passive sampling of the fraction of naphthalene, phenanthrene, pyrene and benzo[a]pyrene in 18 field-contaminated soils. The sampling process of PAHs by TECAM fitted well with a first-order kinetics model and PAHs reached 95% of equilibrium in TECAM within 20 h. Concentrations of PAHs in TECAM (C{sub TECAM}) correlated well with the concentrations in soils (r{sup 2} = 0.693-0.962, p < 0.001). Furthermore, concentrations of PAHs determined in the soil solution were very close to the values estimated by C{sub TECAM} and the partition coefficient between TECAM and water (K{sub TECAM-w}). After lipid normalization nearly 1:1 relationships were observed between PAH concentrations in TECAMs and earthworms exposed to the soils (r{sup 2} = 0.591-0.824, n = 18, p < 0.01). These results suggest that TECAM can be a useful tool to predict bioavailability of PAHs in field-contaminated soils. - Triolein embedded cellulose acetate membranes can be a useful tool to predict bioavailability of PAHs in field-contaminated soils.

  11. Giardia Cysts and Cryptosporidium Oocysts in Membrane-Filtered Municipal Wastewater Used for Irrigation▿

    OpenAIRE

    Lonigro, A.; Pollice, A; Spinelli, R; Berrilli, F.; Di Cave, D.; D'Orazi, C.; Cavallo, P; Brandonisio, O.

    2006-01-01

    A wastewater tertiary treatment system based on membrane ultrafiltration and fed with secondary-treated municipal wastewater was evaluated for its Giardia cyst and Cryptosporidium oocyst removal efficiency. Giardia duodenalis (assemblages A and B) and Cryptosporidium parvum were identified in feed water but were found in filtered water only during occasional failure of the filtration system.

  12. Anaerobic incubation of membrane filter cultures for improved detection of fecal coliforms from recreational waters.

    OpenAIRE

    Doyle, J D; Tunnicliff, B; Brickler, S K; Kramer, R E; Sinclair, N. A.

    1984-01-01

    Anaerobic incubation of membrane filter cultures significantly enhanced detection of fecal coliforms in surface-water samples from recreational beaches. In contrast to standard aerobic incubation, anaerobic incubation suppressed overgrowth of masking, noncoliform bacteria but did not increase the frequency of fecal coliform recovery.

  13. Comparison of Verification Procedures for the Membrane Filter Total Coliform Technique

    OpenAIRE

    LeChevallier, Mark W.; Cameron, Susan C.; McFeters, Gordon A.

    1983-01-01

    Verification of membrane filter total coliform colonies from drinking water was increased 87% by testing for the presence of β-galactosidase and cytochrome oxidase, compared with verification by determination of gas production in lauryl tryptose broth. Over 90% of the coliforms verified by testing for β-galactosidase and cytochrome oxidase were representative of the typical coliform genera.

  14. Colorimetric elastase sensor with peptide conjugated cellulose nanocrystals is interfaced to dialysis membranes

    Science.gov (United States)

    Clinical detection of human neutrophil elastase (HNE) as point of care biomarker or in situ colorimetric adjuvant to chronic wound dressings presents potential advantages in the management of chronic wounds. A colorimetric approach to the detection of HNE using cotton cellulose nanocrystals (CCN) i...

  15. A Hemoperfusion Column Based on Activated Carbon Granules Coated with an Ultrathin Membrane of Cellulose Acetate

    NARCIS (Netherlands)

    Tijssen, Johan; Bantjes, Adriaan; Doorn , van Albert W.J.; Feijen, Jan; Dijk, van Boudewijn; Vonk, Carel R.; Dijkhuis, Ido C.

    1979-01-01

    A hemoperfusion system has been developed which makes use of activated carbon encapsulated with cellulose acetate. Studies have revealed that there are no stagnant flow regions in the column, there i? minimal particle release and the coating is 30 Å thick. The relationships between pore size, pore v

  16. Monolith filter apparatus and membrane apparatus, and method using same

    Energy Technology Data Exchange (ETDEWEB)

    Goldsmith, Robert L. (Wayland, MA)

    2012-04-03

    A filtration apparatus that separates a liquid feedstock mixed with a gas into filtrate and retentate, the apparatus including at least one filtration device comprised of at least one monolith segment of porous material that defines a plurality of passageways extending longitudinally from a feed face of the structure to a retentate end face. The filtration device contains at least one filtrate conduit within it for carrying filtrate toward a filtrate collection zone, the filtrate conduit providing a path of lower flow resistance than that of alternative flow paths through the porous material of the device. The filtration device can also be utilized as a membrane support for a device for microfiltration, ultrafiltration, nanofiltration, reverse osmosis, or pervaporation. Also disclosed is a method for using such a filtration apparatus.

  17. WATER RETENTION VALUE MEASUREMENTS OF CELLULOSIC MATERIALS USING A CENTRIFUGE TECHNIQUE

    Directory of Open Access Journals (Sweden)

    Jinxin Wang

    2010-07-01

    Full Text Available A centrifugal method has been modified and applied to the assessment of water retention value (WRV in cellulosic materials. Microcrystalline cellulose (MCC, small particles/fibrils isolated from MCC using high-pressure homogenizer, and pulp fibers saturated in water were centrifuged at different speeds and times with filter paper and/or a membrane acting as the filter in the WRV measurement setup. As centrifugal speed, time, and filter pore-size increased, lower WRVs were obtained. Smaller MCC particles/fibrils retained more water than the as-received MCC and pulp fibers. The results are useful for WRV measurements of cellulosic materials, especially for microfibrillated cellulose and small cellulosic fibrils.

  18. 纤维素/丝素复合膜的制备与性能%Preparation and Properties of Cellulose-Silk Compound Membrane

    Institute of Scientific and Technical Information of China (English)

    李娟; 何建新

    2011-01-01

    cellulose-silk compound membrane was prepared by solvent -casting method with cellulose and silk. The optimization ratio of compound membrane is 90% of cellulose and 10% of silk in blend membrane. The mechanical properties and aqueous stability and water vapor permeability coefficient of the compound membrane were obviously improved contrary to a single component membrane because of the strong hydrogen bonding interaction and good compatibility between cellulose and silk. X-ray diffraction was verified crystallization properties further.%通过共混法制备了纤维素/丝素复合膜,复合膜的最佳配比为纤维素占共混膜的90%,丝素占10%。在此条件下形成的复合膜的力学性能、水溶液稳定性、水蒸汽透过系数较单一成分的膜有明显改善,纤维素与丝素之间存在着氢键等强烈的相互作用和良好的相容性。X射线衍射分析进一步验证了复合膜的结晶性能。

  19. The mechanism of Acetobacter xylinum cellulose biosynthesis: direction of chain elongation and the role of lipid pyrophosphate intermediates in the cell membrane

    International Nuclear Information System (INIS)

    The biosynthesis of Acetobacter xylinum ATCC 10821 cellulose has been studied with resting cells and a membrane preparation using 14C-pulse and chase reactions, with d-glucose and UDPGlc, respectively. Cellulose was biosynthesized from UDPGlc, and it was found to be tightly associated with both the cells and the membrane. The cellulose chains could be released from the cells and the membrane preparation by treating at pH 2, 100 C for 20 min. The cellulose chains that were released from the pulse and pulse-chase reactions were purified and separated from any low molecular weight substances by gel chromatography on Bio-Gel P4. They were then reduced with sodium borohydride and hydrolyzed with 4 M trifluoroacetic acid at 121 C for 2 h. Labeled products from the acid hydrolyzates were separated by paper chromatography and found to be d-glucose and d-glucitol. The amount of radioactivity in the products was determined by liquid scintillation counting. It was found that the pulsed products from the resting cells gave a ratio of d-[14C]glucitol to d-[14C]glucose of 1:11, and after chasing, the ratio decreased to 1:36. The pulsed products from the membrane gave a ratio of d-[14C]glucitol to d-[14C]glucose of 1:12, and after chasing for 5 min the ratio decreased to 1:43, and after 10 min, the ratio decreased to 1:66. These results show that the labeled d-glucitol obtained from the reducing end of the cellulose chain is chased into the interior of the cellulose chain during synthesis, showing that the cellulose chain is elongated from the reducing end. An insertion mechanism for the synthesis of cellulose from UDPGlc is proposed that involves lipid pyrophosphate glycosyl intermediates and three membrane enzymes: lipid phosphate:UDPGlc phosphotransferase, cellulose synthase, and lipid pyrophosphate phosphohydrolase. (Copyright (c) 1998 Elsevier Science B.V., Amsterdam. All rights reserved.)

  20. The CELLULOSE-SYNTHASE LIKE C (CSLC) Family of Barley Includes Members that Are Integral Membrane Proteins Targeted to the Plasma Membrane

    Institute of Scientific and Technical Information of China (English)

    Fenny M. Dwivany; Dina Yuli; Rachel A. Burton; Neil J. Shirley; Sarah M. Wilson; Geoffrey B. Fincher; Antony Bacic; Ed Newbigin; Monika S. Doblin

    2009-01-01

    The CELLULOSESYNTHASE-LIKE C(CSLC) family is an ancient lineage within the CELLULOSE SYNTHASE/CEL-LULOSE SYNTHASE-LIKE (CESA/CSL) polysaccharide synthase superfamily that is thought to have arisen before the diver-gence of mosses and vascular plants. As studies in the flowering plant Arabidopsis have suggested synthesis of the (1,4)-β-glucan backbone of xyloglucan (XyG), a wall polysaccharide that tethers adjacent cellulose microfibrils to each other, as a probable function for the CSLCs, CSLC function was investigated in barley (Hordeum vulgare L.), a species with low amounts of XyG in its walls. Four barley CSLC genes were identified (designated HvCSLC1-4). Phylogenetic analysis reveals three well supported clades of CSLCs in flowering plants, with barley having representatives in two of these clades. The four barley CSLCs were expressed in various tissues, with in situ PCR detecting transcripts in all cell types of the coleoptile and root, including cells with primary and secondary cell walls. Co-expression analysis showed that HvCSLC3 was coor-dinately expressed with putative XyG xylosyltransferase genes. Both immuno-EM and membrane fractionation showed that HvCSLC2 was located in the plasma membrane of barley suspension-cultured cells and was not in internal membranes such as endoplasmic reticulum or Golgi apparatus. Based on our current knowledge of the sub-cellular locations of poly-saccharide synthesis, we conclude that the CSLC family probably contains more than one type of polysaccharide synthase.

  1. Preparation and Application of Chitosan Membranes to Filter Silver from X-ray Film Processing Wastes

    Science.gov (United States)

    Nyoman Rupiasih, N.; Rustam Purnomo, Rendra; Sumadiyasa, Made

    2016-04-01

    Chitosan is a natural polysaccharide biopolymer which has been widely used in different processes and applications. Chitosan based membranes have been used in reverse osmosis, gas separation, dialysis and pervaporation. The object of this research was investigating the possibility of chitosan membrane used as a filter for removing silver (Ag) from X-ray film processing wastes. Several of chitosan membranes such as M1, M2, M3 and M4 have been prepared for the purpose and filtration was done using dead-end filtration method. The filtration experiments were performed on a flat sheet membrane using pure water and X-ray film processing wastes as feeds. The analysis of silver concentration has been done by atomic absorption spectrometers (AAS). The results show that chitosan membrane M2 gave the highest filtration coefficient (Rcoeff ) i.e. 99.9%, with the pure water flux (PWF) and product flux (PF) are 2972.56 L/m2h and 1761.18 L/m2h respectively. The rejection coefficient of the membranes decreases with increasing the amount of chitosan, while the pure water flux and product flux are increased. The filtration coefficients show that the chitosan membranes are able to filter silver waste from X-ray film processing wastes with performance dependent on their characteristic such as pores size. This suggests that, chitosan membrane can be used as one method that is safe and friendly environment for recovering silver from X-ray film processing waste to improve the quality of treated to an acceptable quality level.

  2. Propylene/propane permeation properties of ethyl cellulose (EC) mixed matrix membranes fabricated by incorporation of nanoporous graphene nanosheets

    Science.gov (United States)

    Yuan, Bingbing; Sun, Haixiang; Wang, Tao; Xu, Yanyan; Li, Peng; Kong, Ying; Niu, Q. Jason

    2016-06-01

    Nanopore containing graphene nanosheets were synthesized by graphene oxide and a reducing agent using a facile hydrothermal treatment in sodium hydroxide media. The as-prepared nanoporous graphene was incorporated into ethyl cellulose (EC) to prepare the mixed matrix membranes (MMMs) for C3H6/C3H8 separation. Transmission electron microscopy (TEM) photograph and X-ray photoelectron spectroscopy (XPS) analysis of nanoporous graphene nanosheets indicated that the structure of nano-pore was irregular and the oxygen-containing groups in the surface were limited. More importantly, the as-prepared MMMs presented better separation performance than that of pristine EC membrane due to simultaneous enhancement of C3H6 permeability and ideal selectivity. The ideal selectivity of the MMMs with 1.125 wt‰ nanoporous graphene content for C3H6/C3H8 increased from 3.45 to 10.42 and the permeability of C3H6 increased from 57.9 Barrer to 89.95 Barrer as compared with the pristine membrane. The presumed facilitated mechanism was that the high specific surface area of nanoporous graphene in polymer matrix increased the length of the tortuous pathway formed by nanopores for the gas diffusion as compared with the pristine graphene nanosheets, and generated a rigidified interface between the EC chains and fillers, thus enhanced the diffusivity selectivity. Therefore, it is expected that nanoporous graphene would be effective material for the C3H6/C3H8 separation.

  3. Grafting of cellulose acetate with ionic liquids for biofuel purification by a membrane process: Influence of the cation.

    Science.gov (United States)

    Hassan Hassan Abdellatif, Faten; Babin, Jérôme; Arnal-Herault, Carole; David, Laurent; Jonquieres, Anne

    2016-08-20

    A new strategy was developed for grafting ionic liquids (ILs) onto cellulose acetate in order to avoid IL extraction and improve its performance for ethyl tert-butyl ether (ETBE) biofuel purification by the pervaporation membrane process. This work extended the scope of IL-containing membranes to the challenging separation of organic liquid mixtures, in which these ILs were soluble. The ILs contained the same bromide anion and different cations with increasing polar feature. The membrane properties were strongly improved by IL grafting. Their analysis in terms of structure-property relationships revealed the influence of the IL content, chemical structure and chemical physical parameters α, β, π* in the Kamlet-Taft polarity scale. The ammonium IL led to the best normalized flux of 0.182kg/m(2)h for a reference thickness of 5μm, a permeate ethanol content of 100% and an outstanding infinite separation factor for the azeotropic mixture EtOH/ETBE at 50°C. PMID:27178937

  4. Propylene/propane permeation properties of ethyl cellulose (EC) mixed matrix membranes fabricated by incorporation of nanoporous graphene nanosheets

    Science.gov (United States)

    Yuan, Bingbing; Sun, Haixiang; Wang, Tao; Xu, Yanyan; Li, Peng; Kong, Ying; Niu, Q. Jason

    2016-01-01

    Nanopore containing graphene nanosheets were synthesized by graphene oxide and a reducing agent using a facile hydrothermal treatment in sodium hydroxide media. The as-prepared nanoporous graphene was incorporated into ethyl cellulose (EC) to prepare the mixed matrix membranes (MMMs) for C3H6/C3H8 separation. Transmission electron microscopy (TEM) photograph and X-ray photoelectron spectroscopy (XPS) analysis of nanoporous graphene nanosheets indicated that the structure of nano-pore was irregular and the oxygen-containing groups in the surface were limited. More importantly, the as-prepared MMMs presented better separation performance than that of pristine EC membrane due to simultaneous enhancement of C3H6 permeability and ideal selectivity. The ideal selectivity of the MMMs with 1.125 wt‰ nanoporous graphene content for C3H6/C3H8 increased from 3.45 to 10.42 and the permeability of C3H6 increased from 57.9 Barrer to 89.95 Barrer as compared with the pristine membrane. The presumed facilitated mechanism was that the high specific surface area of nanoporous graphene in polymer matrix increased the length of the tortuous pathway formed by nanopores for the gas diffusion as compared with the pristine graphene nanosheets, and generated a rigidified interface between the EC chains and fillers, thus enhanced the diffusivity selectivity. Therefore, it is expected that nanoporous graphene would be effective material for the C3H6/C3H8 separation. PMID:27352851

  5. Bulk-Micromachined Optical Filter Based on Guided-Mode Resonance in Silicon-Nitride Membrane

    Science.gov (United States)

    Hsu, Che-Lung; Liu, Yung-Chih; Wang, Chih-Ming; Wu, Mount-Learn; Tsai, Ya-Lun; Chou, Yue-Hong; Lee, Chien-Chieh; Chang, Jenq-Yang

    2006-04-01

    In this paper, a single-layer guided-mode resonance (GMR) filter based on a free-standing silicon-nitride membrane suspended on a silicon substrate is achieved by using bulk-micromachining technology. Both of grating and waveguide structures without a lower-cladding layer, i.e., substrate, are fabricated simultaneously on a silicon-nitride membrane. The device can be used as a transmission bandstop filter with the advantages of simple structure, high efficiency, and feasibility to integrate with other optoelectronic elements into a microsystem chip. The design consideration, fabrication procedures, and measured spectral response are shown in this paper. Moreover, by stacking two proposed devices, Δλ of the stopband at a transmission below 10% is 5.06 nm.

  6. Diffusion mechanism during the swelling hidroxy-methyl cellulose membrane formation

    Science.gov (United States)

    Espinoza-Gomez, Heriberto; Ramos-Olmos, Raudel; Garcia-Rios, Cesar; Lin, Shui Wai; Rogel-Hernandez, Eduardo; Ames-Lopez, Ana

    2007-08-01

    The conduction properties of HMC polymer gel prepared by the phase inversion method were investigated through the diffusion coefficient in order to confirm the conduction mechanism. The solution introduced in the polymer is stored in the pores and then penetrates into the polymer chains. For swelling the polymer network. A model describing the swelling hidroxy-methyl cellulose is presented. The model is used to predict the type liquid liquid phase separation (instantaneous or delayed) that occurs when HMC-PVPD-Solvent-Water casting solutions are immersed in a gelation bath. The model includes the thermodynamic interactions parameters and the transport parameters. The predictions of the model agree with the experimental observations.

  7. Biochemical studies of mouse brain tubulin: colchicine binding (DEAE-cellulose filter) assay and subunits (. cap alpha. and. beta. ) biosynthesis and degradation (in newborn brain)

    Energy Technology Data Exchange (ETDEWEB)

    Tse, Cek-Fyne

    1978-01-01

    A DEAE-cellulose filter assay, measuring (/sup 3/H)colchicine bound to colchicine binding protein (CBP) absorbed on filter discs, has been modified to include lM sucrose in the incubation medium for complexing colchicine to CBP in samples before applying the samples to filter discs (single point assay). Due to the much greater stability of colchicine binding capacity in the presence of lM sucrose, multiple time-point assays and least squares linear regression analysis were not necessary for accurate determination of CBP in hybrid mouse brain at different stages of development. The highest concentrations of CBP were observed in the 160,000g supernatant and pellet of newborn brain homogenate. Further studies of the modified filter assay documented that the assay has an overall counting efficiency of 27.3%, that DEAE-cellulose filters bind and retain all tubulin in the assay samples, and that one molecule of colchicine binds approximately one molecule of tubulin dimer. Therefore, millimoles of colchicine bound per milligram total protein can be used to calculate tubulin content. With this technique tubulin content of brain supernatant was found to be 11.9% for newborn, and 7.15% for 11 month old mice. Quantitative densitometry was also used to measure mouse brain supernatant actin content for these two stages. In vivo synthesis and degradation rates of tubulin ..cap alpha.. and ..beta.. subunits of two day mouse brain 100,000g supernatant were studied after intracerebral injection of (/sup 3/H)leucine. Quantitative changes of the ratio of tritium specific activities of tubulin ..cap alpha.. and ..beta.. subunits with time were determined. The pattern of change was biphasic. During the first phase the ratio decreased; during the second phase the ratio increased continuously. An interpretation consistent with all the data in this study is that the ..cap alpha.. subunit is synthesized at a more rapid rate than the ..beta.. subunit. (ERB)

  8. Biochemical studies of mouse brain tubulin: colchicine binding (DEAE-cellulose filter) assay and subunits (α and β) biosynthesis and degradation (in newborn brain)

    International Nuclear Information System (INIS)

    A DEAE-cellulose filter assay, measuring [3H]colchicine bound to colchicine binding protein (CBP) absorbed on filter discs, has been modified to include lM sucrose in the incubation medium for complexing colchicine to CBP in samples before applying the samples to filter discs (single point assay). Due to the much greater stability of colchicine binding capacity in the presence of lM sucrose, multiple time-point assays and least squares linear regression analysis were not necessary for accurate determination of CBP in hybrid mouse brain at different stages of development. The highest concentrations of CBP were observed in the 160,000g supernatant and pellet of newborn brain homogenate. Further studies of the modified filter assay documented that the assay has an overall counting efficiency of 27.3%, that DEAE-cellulose filters bind and retain all tubulin in the assay samples, and that one molecule of colchicine binds approximately one molecule of tubulin dimer. Therefore, millimoles of colchicine bound per milligram total protein can be used to calculate tubulin content. With this technique tubulin content of brain supernatant was found to be 11.9% for newborn, and 7.15% for 11 month old mice. Quantitative densitometry was also used to measure mouse brain supernatant actin content for these two stages. In vivo synthesis and degradation rates of tubulin α and β subunits of two day mouse brain 100,000g supernatant were studied after intracerebral injection of [3H]leucine. Quantitative changes of the ratio of tritium specific activities of tubulin α and β subunits with time were determined. The pattern of change was biphasic. During the first phase the ratio decreased; during the second phase the ratio increased continuously. An interpretation consistent with all the data in this study is that the α subunit is synthesized at a more rapid rate than the β subunit

  9. Cellulose Synthesis and Its Regulation

    OpenAIRE

    Li, Shundai; Bashline, Logan; Lei, Lei; Gu, Ying

    2014-01-01

    Cellulose, the most abundant biopolymer synthesized on land, is made of linear chains of ß (1–4) linked D-glucose. As a major structural component of the cell wall, cellulose is important not only for industrial use but also for plant growth and development. Cellulose microfibrils are tethered by other cell wall polysaccharides such as hemicellulose, pectin, and lignin. In higher plants, cellulose is synthesized by plasma membrane-localized rosette cellulose synthase complexes. Despite the re...

  10. 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.

  11. Characteristics of Flux Decline in Forward Osmosis Process for Asymmetric Cellulose Membrane

    Energy Technology Data Exchange (ETDEWEB)

    Han, Myeong-Jin; Nam, Suk-Tae [Kyungil University, Gyeongsan (Korea, Republic of); Lee, Keun-Woo [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2014-06-15

    This study examined the effect of concentration polarization on permeate flux in forward osmosis (FO) membrane process for saline and sucrose solution. The reduction in permeate flux during the FO membrane process is largely due to the formation of concentration polarization on membrane surfaces. The flux reduction due to internal concentration polarization formed on the porous support layer was larger than that due to the external concentration polarization on the active membrane surface. Water permeate flux through the FO membrane increased nonlinearly with the increase in osmotic pressure. The water permeability coefficient was 1.8081x10{sup -7} m/s·atm for draw solution on active layer (DS-AL) mode and 1.0957-10{sup -7} m/s·atm for draw solution on support layer (DS-SL) mode in NaCl solution system. The corresponding membrane resistance was 5.5306x10{sup 6} and 9.1266x10{sup 6} s·atm/m, respectively. With respect to the sucrose solution, the permeate flux for DS-AL mode was 1.33-1.90 times higher than that for DS-SL mode. The corresponding variation in the permeation flux (J) due to osmotic pressure (π) would be expressed as J=-0.0177+0.4506π-0.0032π{sup 2} for the forward and J=0.0948+0.3292π-0.0037π{sup 2} for the latter.

  12. Polyvinyl alcohol–cellulose composite: a taste sensing material

    Indian Academy of Sciences (India)

    Sarmishtha Majumdar; Basudam Adhikari

    2005-12-01

    There are reports of fabrication of taste sensor by adsorbing lipids into Millipore filter paper. With this lipid based sensor, it has been found that the taste sensing efficiency of membrane can be remarkably improved. We have made an attempt to prepare taste sensor material by using functionalized polymer without any lipid. PVA–cellulose composite has been modified to use as the sensor material. The research work covers polymer membrane preparation, morphology study and structural characterization of the membrane and study of the taste sensing characteristics of this membrane for five different taste substances. PVA–cellulose composite membrane was modified by phosphorylation with POCl3. FTIR spectroscopic analysis, XRD analysis and SEM were done to get an idea about the structure and morphology of the prepared phosphorylated PVA–cellulose composite membrane. The sensor characteristics like temporal stability, response stability, response to different taste substances, and reproducibility of sensing performance were studied using phosphorylated PVA–cellulose composite membrane. Sensor device prepared with this membrane has shown distinct response patterns for different taste substances in terms of membrane potential. Threshold concentrations of phosphorylated PVA–cellulose composite membrane for HCl, NaCl, Q-HCl, sucrose and MSG are 0.001 mM, 0.001 mM, 0.001 mM, 0.001 mM and 0.009 mM, respectively. The threshold concentrations are below human threshold concentrations. Membranes also showed characteristic response patterns for organic acids like acetic acid, citric acid, formic acid etc, mineral acids like HCl, H2SO4 and HNO3 salts, bitter substances, sweet substances and umami substances. Sensor device prepared with this membrane has excellent shelf life.

  13. Extraction and functionalization of bagasse cellulose nanofibres to Schiff-base based antimicrobial membranes.

    Science.gov (United States)

    Bansal, Monica; Chauhan, Ghanshyam S; Kaushik, Anupama; Sharma, Avantika

    2016-10-01

    The work reported in this paper involves synthesis of a nanocellulose/chitosan composite and its further modification to antimicrobial films. Bagasse, an easily available biowaste, was used as source to extract nanocellulose fibres (CNFs) by subjecting it to mechanical and chemical treatments including alkaline steam explosion and high shear homogenization. The CNFs were subjected to periodate oxidation to obtain nanocellulose dialdehyde (CDA). The aldehyde groups of CDA were reacted with amino groups of chitosan to form Schiff-base. The resulting CDA/chitosan composite fibres were characterized at various steps. The fibres were then cast into films using cellulose acetate as a binder. The films have good physical strength. The composite films show excellent antimicrobial properties when tested against Staphylococcus aureus and Escherichia coli. Such antimicrobial films have potential applications in the formation of antimicrobial packaging material. PMID:27316771

  14. Fabrication of a membrane filter with controlled pore shape and its application to cell separation and strong single cell trapping

    International Nuclear Information System (INIS)

    A porous membrane filter is one of the key components for sample preparation in lab-on-a-chip applications. However, most of the membranes reported to date have only been used for size-based separation since it is difficult to provide functionality to the membrane or improve the performance of the membrane. In this work, as a method to functionalize the membrane filter, controlling the shape of the membrane pores is suggested, and a convenient and mass-producible fabrication method is provided. With the proposed method, membrane filters with round, conical and funnel shape pores were successfully fabricated, and we demonstrated that the sidewall slope of the conical shape pores could be precisely controlled. To verify that the membrane filter can be functionalized by controlled pore shape, we investigated filtration and trapping performance of the membrane filter with conical shape pores. In a filtration test of 1000 cancer cells (MCF-7, a breast cancer cell line) spiked in phosphate buffered saline (PBS) solution, 77% of the total cancer cells were retained on the membrane, and each cell from among 99.3% of the retained cells was automatically isolated in a single conical pore during the filtration process. Thanks to its engineered pore shape, trapping ability of the membrane with conical pores is dramatically improved. Microparticles trapped in the conical pores maintain their locations without any losses even at a more than 30 times faster external flow rate com-pared with those mounted on conventional cylindrical pores. Also, 78% of the cells trapped in the conical pores withstand an external flow of over 300 μl min−1 whereas only 18% of the cells trapped in the cylindrical pores remain on the membrane after 120 μl min−1 of an external flow is applied. (paper)

  15. Growth of silicone-immobilized bacteria on polycarbonate membrane filters, a technique to study microcolony formation under anaerobic conditions

    DEFF Research Database (Denmark)

    Højberg, Ole; Binnerup, S. J.; Sørensen, Jan

    1997-01-01

    A technique was developed to study microcolony formation by silicone- immobilized bacteria on polycarbonate membrane filters under anaerobic conditions. A sudden shift to anaerobiosis was obtained by submerging the filters in medium which was depleted for oxygen by a pure culture of bacteria. The...

  16. Microfibrillated cellulose sheets coating oxygen-permeable PDMS membranes induce rat hepatocytes 3D aggregation into stably-attached 3D hemispheroids.

    Science.gov (United States)

    Evenou, Fanny; Couderc, Sandrine; Kim, Beomjoon; Fujii, Teruo; Sakai, Yasuyuki

    2011-01-01

    Here we report the use of natural, chemically-unmodified, microfibrillated cellulose (MFC) as a matrix for hepatocyte culture. We developed an original cell-culture design composed of a thin 3D-microstructured fibrous substrate consisting of a MFC sheet coating a highly O(2)-permeable polydimethylsiloxane (PDMS) membrane. The MFC-coated PDMS membranes were obtained according to a simple process where cellulose fibres were deposited from an aqueous suspension on the PDMS surfaces and the films were dried under mild conditions. To enable oxygen diffusion through the membranes, they were assembled on bottomless frames ('O(2)+' condition). Rat hepatocytes primary-cultured on such MFC-PDMS membranes quickly organized themselves into large hemispherical 3D aggregates which were tightly anchored to the MFC sheets. In contrast, hepatocytes cultured on smooth PDMS membranes in the O(2)+ system (O(2)+, PDMS) organized into unstable 2D monolayers which easily detached from the surfaces. Hepatocyte 3D cultures obtained on MFC-PDMS membranes exhibited higher liver-specific functions over a 2-week culture period, as assessed by both the higher albumin secretion and urea synthesis rate. The MFC-PDMS membranes appear suitable for obtaining stably-attached and functional hepatocyte 3D cultures and appear interesting for drug/chemical screenings in a microplate format, but also for microfluidic applications. PMID:20626957

  17. Rapid method for the differentiation of gram-positive and gram-negative bacteria on membrane filters.

    OpenAIRE

    Romero, S; Schell, R F; Pennell, D R

    1988-01-01

    Microfiltration has become a popular procedure for the concentration and enumeration of bacteria. We developed a rapid and sensitive method for the differentiation of gram-positive and gram-negative bacteria, utilizing a polycarbonate membrane filter, crystal violet, iodine, 95% ethanol, and 6% carbol fuchsin, that can be completed in 60 to 90 s. Gram reactions of 49 species belonging to 30 genera of bacteria were correctly determined by the filter-Gram stain. The sensitivities of the filter-...

  18. Nonstationary filtered shot-noise processes and applications to neuronal membranes

    Science.gov (United States)

    Brigham, Marco; Destexhe, Alain

    2015-06-01

    Filtered shot noise processes have proven to be very effective in modeling the evolution of systems exposed to shot noise sources and have been applied to a wide variety of fields ranging from electronics through biology. In particular, they can model the membrane potential Vm of neurons driven by stochastic input, where these filtered processes are able to capture the nonstationary characteristics of Vm fluctuations in response to presynaptic input with variable rate. In this paper we apply the general framework of Poisson point processes transformations to analyze these systems in the general case of nonstationary input rates. We obtain exact analytic expressions, as well as different approximations, for the joint cumulants of filtered shot noise processes with multiplicative noise. These general results are then applied to a model of neuronal membranes subject to conductance shot noise with a continuously variable rate of presynaptic spikes. We propose very effective approximations for the time evolution of the Vm distribution and a simple method to estimate the presynaptic rate from a small number of Vm traces. This work opens the perspective of obtaining analytic access to important statistical properties of conductance-based neuronal models such as the first passage time.

  19. An ultrasensitive bio-surrogate for nanoporous filter membrane performance metrology directed towards contamination control in microlithography applications

    Science.gov (United States)

    Ahmad, Farhan; Mish, Barbara; Qiu, Jian; Singh, Amarnauth; Varanasi, Rao; Bedford, Eilidh; Smith, Martin

    2016-03-01

    Contamination tolerances in semiconductor manufacturing processes have changed dramatically in the past two decades, reaching below 20 nm according to the guidelines of the International Technology Roadmap for Semiconductors. The move to narrower line widths drives the need for innovative filtration technologies that can achieve higher particle/contaminant removal performance resulting in cleaner process fluids. Nanoporous filter membrane metrology tools that have been the workhorse over the past decade are also now reaching limits. For example, nanoparticle (NP) challenge testing is commonly applied for assessing particle retention performance of filter membranes. Factors such as high NP size dispersity, low NP detection sensitivity, and high NP particle-filter affinity impose challenges in characterizing the next generation of nanoporous filter membranes. We report a novel bio-surrogate, 5 nm DNA-dendrimer conjugate for evaluating particle retention performance of nanoporous filter membranes. A technique capable of single molecule detection is employed to detect sparse concentration of conjugate in filter permeate, providing >1000- fold higher detection sensitivity than any existing 5 nm-sized particle enumeration technique. This bio-surrogate also offers narrow size distribution, high stability and chemical tunability. This bio-surrogate can discriminate various sub-15 nm pore-rated nanoporous filter membranes based on their particle retention performance. Due to high bio-surrogate detection sensitivity, a lower challenge concentration of bio-surrogate (as compared to other NPs of this size) can be used for filter testing, providing a better representation of customer applications. This new method should provide better understanding of the next generation filter membranes for removing defect-causing contaminants from lithography processes.

  20. Efficient performance and the microbial community changes of submerged anaerobic membrane bioreactor in treatment of sewage containing cellulose suspended solid at 25°C.

    Science.gov (United States)

    Watanabe, Ryoya; Nie, Yulun; Takahashi, Shintaro; Wakahara, Shinichiro; Li, Yu-You

    2016-09-01

    Influence of cellulose as suspended solid (SS) on the performance of submerged anaerobic membrane bioreactor (SAnMBR) was evaluated at 25°C using two types of synthetic sewage (SS contained or not). During the 110days operation, COD and BOD removal, CH4 gas recovery and cellulose accumulation were investigated in detail. The influence of cellulose as SS in sewage on the SAnMBR performance was not significant at HRT longer than12h and 65-72% of the influent COD was recovered as methane gas at HRT of 12h. At HRT of 6h, the quality of effluent got worse and the accumulation of cellulose was found in reactor. 16S rRNA analysis revealed that the microbial diversity distribution including Archaea and Bacteria changed due to the addition of SS in sewage and specific microbe for cellulose degradation such as Proteobacteria was detected. Sludge in SAnMBR could acclimate to characteristics of sewage by self-adaptation. PMID:27235975

  1. Method for the preparation of cellulose acetate flat sheet composite membranes for forward osmosis—Desalination using MgSO4 draw solution

    KAUST Repository

    Sairam, M.

    2011-06-01

    A lab scale method for the preparation of defect free flat sheet composite membranes for forward osmosis (FO) has been developed. Membranes containing a thin layer of cellulose acetate (CA) cast on a nylon fabric of 50μm thick were prepared by phase inversion in water. Cellulose acetate (CA) membranes with an overall thickness of 70-80μm have been prepared with lactic acid, maleic acid and zinc chloride as pore forming agents, at different annealing temperatures, for forward osmosis. These membranes have been tested in the desalination of saline feeds (35g·L-1 of NaCl) using magnesium sulphate solution (150g·L-1) as the draw solution. The water flux, and rejection of NaCl, were compared with those of commercially available membranes tested under the same FO conditions. The commercially available FO membrane from Hydration Technologies Inc, OR (M1) has a permeability of 0.13L·h-1·m-2·bar-1 with a NaCl rejection of 97% when tested with 150g·L-1 of MgSO4 in the draw solution. Another commercially available membrane for FO from Hydration Technologies Inc, OR, M2 has a water permeability of 0.014L·h-1·m-2·bar-1 with NaCl rejection of 100%. The flux and rejection of the CA membranes prepared in this work are found to be dependent on the nature of the pore forming agent, and annealing temperature. Impregnation of an inorganic filler, sodium montmorrillonite in CA membranes and coating of CA membranes with hydrophilic PVA did not enhance the flux of base CA membranes. Cellulose acetate membranes cast from dope solutions containing acetone/isopropanol and lactic acid, maleic acid and zinc chloride as pore forming agents have water permeabilities of 0.13, 0.09 and 0.68L·h-1·m-2·bar-1 respectively, with NaCl rejections of 97.7, 99.3 and 88% when annealed at 50°C. CA membranes prepared with zinc chloride as a pore forming agent have good permeability of 0.27L·h-1·m-2·bar-1 with a NaCl rejection of 95% when annealed at 70°C. © 2011.

  2. Multi-band radio-frequency filters fabricated using polyimide-based membrane transfer bonding technology

    International Nuclear Information System (INIS)

    In this paper, we present a polyimide-based Si membrane transfer bonding technology and its application to CMOS-compatible integration of different modes of AlN/Si composite piezoelectric MEMS resonators. The thermosetting polyimide, which has excellent chemical resistance and thermal stability, is used as a bonding adhesion, and is successfully removed as a sacrificial layer by O2 plasma to release free-standing MEMS devices. The whole process temperature is below 350 °C and compatible with CMOS LSI. Using this technology, different modes of AlN/Si resonators, which are film bulk acoustic wave resonators and wine-glass mode disk-type resonators, have been co-fabricated on the same wafer. We also fabricated a ladder-type FBAR filter with a center frequency of 7.71 GHz and a mechanically coupled disk-array filter with a center frequency of 292.8 GHz.

  3. Life cycle cost reduction through high efficiency membrane based air intake filters; Reduzierung der Lebensdauerzykluskosten durch hocheffiziente Zuluftfilter auf Membranbasis

    Energy Technology Data Exchange (ETDEWEB)

    Krah, Helmut [W.L. Gore and Associates GmbH, Putzbrunn (Germany)

    2011-07-01

    The use of highly efficient, membrane-based air intake filters means that massive savings can be made in the operation of gas turbines: on the one hand, a higher degree of efficiency can be achieved, which leads to lower fuel consumption and better turbine performance, and on the other, maintenance costs can be reduced thanks to the avoidance of erosion and corrosion. EPA (Efficient Particulate Air) filters based on fibreglass have the disadvantage that they exhibit a relatively high differential pressure, and they can frequently only be used by converting the filter house. This is where the tremendous advantage of membrane-based EPA filters comes in. Its core, a micro-porous PTFE membrane with excellent air permeability. (orig.)

  4. Application and Mechanism Study of NMMO Technology-based Natural Cellulose Membrane%NMMO工艺天然纤维素膜的应用及机理研究

    Institute of Scientific and Technical Information of China (English)

    李冬娜; 马晓军

    2013-01-01

    The preparation method and research progress of NMMO technology-based cellulose membrane at home and abroad are discussed, the application of NMMO technology-based cellulose membrane in different fields is introduced, the dissolution mechanism and film-forming mechanism of cellulose membrane are analyzed, and the application prospect of NMMO technology-based cellulose membrane is pointed out.%  论述了NMMO工艺纤维素膜的制备方法及在国内外的研究进展,介绍了NMMO工艺纤维素膜在不同领域的应用现状,分析了纤维素膜的溶解机理及成膜机理,指出了NMMO工艺纤维素膜的应用前景。

  5. 壳聚糖/二醋酸纤维素酯复合薄膜的制备%Synthesis of Composite Membrane of Chitosan/Cellulose Diacetate

    Institute of Scientific and Technical Information of China (English)

    朱超; 姚铭; 张远方; 石红

    2011-01-01

    以香烟嘴棒制备过程废弃的二醋酸纤维素酯丝束和壳聚糖丝束为原料,制备了具有良好稳定性、环境友好、易降解的复合薄膜.探讨了溶解方法、溶剂浓度、干燥条件等对成膜质量的影响.对复合薄膜拉伸强度、断裂伸长率、吸水性进行了表征.结果表明:共混液配制以壳聚糖和二醋酸纤维素酯交替溶入醋酸溶液,并辅以超声混合助溶为佳;共混液流延成膜,用沉淀剂处理并在10~30℃下干燥成膜效果较好.与纯壳聚糖膜相比,随着二醋酸纤维素酯含量的增加,复合薄膜的断裂伸长率逐渐增大,在二醋酸纤维素酯和壳聚糖质量比为3∶1时,最大断裂伸长率比纯壳聚糖膜高7.85%.%Used the cellulose diacetate and chitosan as material,to make the composite mem-brane which had the features of good stability,environmental friendliness,easy degradation.Ex-plored the influence of dissolving method,solvent concentration,drying conditions on membrane quality.Described the tensile-strength,breaking elongation,water imbibition of the composite membrane.The results showed that preparation was good with chitosan and cellulose diacetate in turns dissolved into acetic acid,as well as supersonic assisting;the blending liquid flowed to be membrane,and the quality of membrane was good with 10~30℃ drying and precipitator treatment.Compared with chitosan membrane,as the increase of cellulose diacetate,the breaking elongation of composite membrane gradually increased.When the mass ratio of cellulose diacetate to chitosan was 3∶1,the biggest breaking elongation of composite membrane was 7.85% higher than that of chitosan membrane.

  6. Visualization of particle complexes in the plasma membrane of Micrasterias denticulata associated with the formation of cellulose fibrils in primary and secondary cell walls

    OpenAIRE

    1980-01-01

    Highly ordered arrays of intramembrane particles are observed in freeze- fractured plasma membranes of the green alga Micrasterias denticulata during the synthesis of the secondary cell wall. The observable architecture of the complex consists primarily of a precise hexagonal array of from 3 to 175 rosettes, consisting of 6 particles each, which fracture with the P-face. The complexes are observed at the ends of impressions of cellulose fibrils. The distance between rows of rosettes is equal ...

  7. Visualization of particle complexes in the plasma membrane of Micrasterias denticulata associated with the formation of cellulose fibrils in primary and secondary cell walls.

    Science.gov (United States)

    Giddings, T H; Brower, D L; Staehelin, L A

    1980-02-01

    Highly ordered arrays of intramembrane particles are observed in freeze-fractured plasma membranes of the green alga Micrasterias denticulata during the synthesis of the secondary cell wall. The observable architecture of the complex consists primarily of a precise hexagonal array of from 3 to 175 rosettes, consisting of 6 particles each, which fracture with the P-face. The complexes are observed at the ends of impressions of cellulose fibrils. The distance between rows of rosettes is equal to the center-to-center distance between parallel cellulose fibrils of the secondary wall. Correlation of the structure of the complex with the pattern of deposition indicates that the size of a given fibril is proportional to the number of rosettes engaged in its formation. Vesicles containing hexagonal arrays of rosettes are found in the cytoplasm and can be observed in the process of fusing with the plasma membrane, suggesting that the complexes are first assembled in the cytoplasm and then incorporated into the plasma membrane, where they become active in fibril formation. Single rosettes appear to be responsible for the synthesis of microfibrils during primary wall growth. Similar rosettes have now been detected in a green alga, in fern protonemata, and in higher plant cells. This structure, therefore, probably represents a significant component of the cellulose synthesizing mechanism in a large variety of plant cells. PMID:7189756

  8. Reducing the bioavailability of PCBs in soil to plant by biochars assessed with triolein-embedded cellulose acetate membrane technique

    International Nuclear Information System (INIS)

    Coupling with triolein-embedded cellulose acetate membrane (TECAM) technique, hydroxypropyl β-cyclodextrins (HPCD) extraction method, and the greenhouse pot experiments, the influences of biochars on polychlorinated biphenyls (PCBs) bioavailability in soil to plant (Brassica chinensis L. and Daucus carota) were investigated. Addition of 2% biochars to soils significantly reduced the uptake of PCBs in plant, especially for di-, tri- and tetra-chlorobiphenyls. PCBs concentrations in the roots of B. chinensis and D. carota were reduced for 61.5–93.7%, and 12.7–62.4%, respectively in the presence of biochars. The kinetic study showed that in the soils amended with/without biochars, PCBs concentrations accumulated in TECAM, as well as in the HPCD extraction solution, followed significant linear relationships with those in plant roots. Application of biochars to soil is a potentially promising method to reduce PCBs bioavailability whereas TECAM technique can be a useful tool to predict the bioavailability of PCBs in soil. -- Highlights: ► Application of biochars significantly reduced the uptake of PCBs in plant. ► TECAM was a new and effective method to predict the PCBs bioavailability in soil. ► PCBs accumulated in TECAM followed significant linear relationships with plant. ► PCBs in TECAM were more similar with the plant uptake than HPCD solution. -- The reduced PCBs concentrations in plant roots by biochars show good linear relationship with those in TECAM

  9. Effect of polyoxyethylene n-alkyl ethers on carrier-mediated transport of lanthanide ions through cellulose triacetate membranes

    International Nuclear Information System (INIS)

    Fluxes of 14 kinds of lanthanides across cellulose triacetate membranes were determined by using mixtures of o-nitrophenyl n-octyl ether and a series of polyoxythylene n-alkyl ethers (POE ethers) as plasticizers, and hinokitiol as carrier. Effects of alkyl and polyoxyethylene (POE) chains of POE ether on the flux were demonstrated. The transport of the lanthanides was coupled to a flow of hydrogen ions. The POE ethers used [CnH2n+1(OCH2CH2)xOH, referred to as CnEx] were C10E3, C12E3, C14E3, C16E3, C12E2, C12E4, C12E6 and C12E8, In all cases, high fluxes were observed for the lanthanides from samarium to lutetium. On the contrary, the fluxes for lanthanum to neodymium were extremely low. In experiments testing the effect of the alkyl chain, the order of the POE ethers in the lanthanide flux for samarium to lutetium was C12E3 > C10E3 > C14E3 >C16E3. In experiments testing the effect of the POE chain, the flux decreased with an increase in the chain length

  10. Studies on electrochemical characterization and performance prediction of cellulose acetate and Zeocarb-225 composite membranes in aqueous NaCl solutions.

    Science.gov (United States)

    Tiwari, A K; Ahmad, Suhail

    2006-06-01

    We have mixed cellulose acetate and Zeocarb-225 in different ratios, leading to the preparations of Membrane-1 and Membrane-2. Membrane potential, water content, and conductance measurements have been carried out to estimate and analyze the data in terms of equilibria and important electrochemical parameters. The Donnan equilibrium has been incorporated to estimate the activity coefficient of counterions, y(p)M, and solute, y(+/-)M in the membrane phase along with the parameter, so called varphi expressing non-ideality. Dependence of the extent of hydrophilicity of both membranes on mean electrolyte concentrations has been examined. Selectivity in membranes is discussed in terms of dissociation equilibria, K(d)s and K(d)f. It has been found that membrane surface charge density sigma(s) increases with increasing of external NaCl concentration. Dependence of water transport number and cationic transport number on electrolyte concentration shows a similar trend of variation. At higher mean concentration of electrolyte, water transport number in Membrane-2 has a negative value. Membrane-2 has a higher value of water transport number than Membrane-1. The entropy production due to solute and water transport has been quantified for both the membranes in the light of nonequilibrium thermodynamics. The various type of interactions such as solute-membrane, solute-water, and water-membrane are analyzed in terms of friction coefficients (f(ij)) of Spiegler's frictional pore model. In our case, an f(wm) diffusion-control criteria, i.e., (D(+/-) . C. d/D(+/-)M C(M) . delta) > 2. A slightly higher value of solute rejection is found in Membrane-2. PMID:16499917

  11. Membrane filter method to study the effects of Lactobacillus acidophilus and Bifidobacterium longum on fecal microbiota.

    Science.gov (United States)

    Shimizu, Hidenori; Benno, Yoshimi

    2015-11-01

    A large number of commensal bacteria inhabit the intestinal tract, and interbacterial communication among gut microbiota is thought to occur. In order to analyze symbiotic relationships between probiotic strains and the gut microbiota, a ring with a membrane filter fitted to the bottom was used for in vitro investigations. Test strains comprising probiotic nitto strains (Lactobacillus acidophilus NT and Bifidobacterium longum NT) and type strains (L. acidophilus JCM1132(T) and B. longum JCM1217(T) ) were obtained from diluted fecal samples using the membrane filter to simulate interbacterial communication. Bifidobacterium spp., Streptococcus pasteurianus, Collinsella aerofaciens, and Clostridium spp. were the most abundant gut bacteria detected before coculture with the test strains. Results of the coculture experiments indicated that the test strains significantly promote the growth of Ruminococcus gnavus, Ruminococcus torques, and Veillonella spp. and inhibit the growth of Sutterella wadsworthensis. Differences in the relative abundances of gut bacterial strains were furthermore observed after coculture of the fecal samples with each test strain. Bifidobacterium spp., which was detected as the dominant strain in the fecal samples, was found to be unaffected by coculture with the test strains. In the present study, interbacterial communication using bacterial metabolites between the test strains and the gut microbiota was demonstrated by the coculture technique. The detailed mechanisms and effects of the complex interbacterial communications that occur among the gut microbiota are, however, still unclear. Further investigation of these relationships by coculture of several fecal samples with probiotic strains is urgently required. PMID:26486646

  12. 纤维素/NMMO溶液及其薄膜的制备与性能研究%Preparation and properties of cellulose/NMMO solution and membrane

    Institute of Scientific and Technical Information of China (English)

    张伟; 陈朝见; 傅师申

    2011-01-01

    以水质量分数为13.35%~11%的纤维素/NMMO溶液.将所得溶液制备纤维素薄膜,考察了纤维素/NMMO溶液的稳定性,研究了凝固浴温度和组成对纤维索薄膜的成膜性、断面形态及力学性能的影响.结果表明:纤维素/NMMO溶液随着浓度增大,其牯度先增大后减小,再急剧上升;纤维素/NMMO溶液在玻璃介质中稳定性较好,微量Cu2+,Fe3+等杂质存在时,其稳定性显著下降;纤维素薄膜随凝固浴温度升高,其透明性、拉伸强度和断裂伸长率均下降;相对于水,含有乙醇和NMMO的凝固浴能减缓双扩散的速度,使纤维素薄膜的拉伸强度略有提高,断裂伸长率出现不同程度下降.%A cellulose/N-methyl morpholine-N-oxide (NMMO) solution with the mass fraction of 5% -11% was prepared by dissoloving cotton pulp with NMMO containing 13.3% water by mass fraction as a solvent. The obtained solution was used to prepare cellulose membrane. The stability of cellulose/NMMO solution was investigated. The effects of coagulation bath temperature and composition on the formation, fracture morphology and mechanical properties of the cellulose membrane were studied. The results showed that the viscosity of the cellulose/NMMO solution increased, then decreased and finally appeared a steep rise while increasing the solution concentration. The cellulose/NMMO solution exhibited fairly good stability in glass medium. The exitence of trace Cu2 + and Fe3 + caused the stability to decline obviously. The transparency, tensile strength and elongation at break of the ycellulose membrane were decreased while elevating the coagulation bath temperature. As compared with water, the coagulation bath containing ethanol and NMMO can depress the double diffusion speed , slightly increase the tensile strength and decrease the elongation at break in different degree.

  13. Regular silicon pillars and dichroic filters produced via particle-imprinted membranes

    Science.gov (United States)

    Ladenburger, Andreas; Reiser, Anton; Konle, Johannes; Feneberg, Martin; Sauer, Rolf; Thonke, Klaus; Yan, Feng; Goedel, Werner A.

    2007-02-01

    We have produced regular silicon pillar arrays and porous gold films on the 100 nm scale without any optical or e-beam lithography. Using particle-assisted wetting we produced a nanoporous polymer membrane on silicon. The membrane incorporated a regular array of pores generated by embedding silica particles in an organic liquid and subsequently removing the particles after polymerization of the liquid. Gold vapor was deposited onto the silicon wafer coated by the porous polymer structure. This process created an array of gold dots on the substrate at the bottom of the pores, and at the same time, a sievelike porous gold layer on top of the polymer matrix. The top layer was lifted off and used as an optical short-pass filter. After removal of the polymer membrane, the remaining gold dot pattern on the substrate served as a mask in a deep reactive ion etching process. We obtain large-area arrays of silicon nanopillars up to 1.5 μm in height and below 200 nm in diameter.

  14. Transport Selectivity of a Diethylene Glycol Dimethacrylate-Based Thymine-imprinted Polymeric Membrane over a Cellulose Support for Nucleic Acid Bases

    Institute of Scientific and Technical Information of China (English)

    QU Xiang-Jin; CHEN Chang-Bao; ZHOU Jie; WU Chun-Hui

    2007-01-01

    The binding mechanism between 9-vinyladenine and pyrimidine base thymine in methanol was studied with UV-visible spectrophotometric method. Based on this study, using thymine as a template molecule, 9-vinyladenine as a novel functional monomer and diethylene glycol dimethacrylate as a new cross-linker, a specific diethylene glycol dimethacrylate-based molecularly imprinted polymeric membrane was prepared over a cellulose support.Then, the resultantly polymeric membrane morphologies were visualized with scanning electron microscopy and its permselectivity was examined using thymine, uracil, cytosine, adenine and guanine as substrates. This result showed that the imprinting polymeric membrane prepared with diethylene glycol dimethacrylate exhibited higher transport capacity for the template molecule thymine and its optimal analog uracil than other nucleic acid bases. The membrane also took on higher permselectivity than the imprinted membrane made with ethylene glycol dimethacrylate as a cross-linker. When a mixture including five nucleic acid bases thymine, uracil, cytosine, adenine and guanine passed through the diethylene glycol dimethacrylate-based thymine-imprinted polymeric membrane,recognition of the membrane for the template molecule thymine and its optimal analog uracil was demonstrated. It was predicted that the molecularly imprinted membrane prepared with diethylene glycol dimethacrylate as cross-linker might be applicable to thymine assay of absolute hydrolysates of DNA or uracil assay of absolute hydrolysates of RNA in biological samples because of its high selectivity for the template molecule thymine and its optimal analog uracil.

  15. Preparation and Performance of Cellulose/Poly(Hydroxybutyrate) Electroactive Composite Membrane%纤维素/聚羟基丁酸酯电活性复合膜的制备及性能

    Institute of Scientific and Technical Information of China (English)

    蔡志江; 史杏娟; 樊亚男

    2013-01-01

    以三氟乙酸为溶剂,采用溶液共混旋转浇注法制备了纤维素/聚羟基丁酸酯电活性复合膜材料.通过扫描电子显微镜、红外光谱、差示扫描量热分析、X射线衍射对复合膜材料进行了表征,并测试了复合膜材料的力学性能与电活性性能.结果表明,复合膜材料中纤维素的结晶规整度下降,结晶度指数下降了29%;复合膜材料的断裂强度、断裂伸长率及杨氏模量分别为74MPa、7.2%和2.5GPa,较PHB有较大的提高;电活性复合膜材料最高可产生1.35cm的弯曲应变响应,较纯纤维素膜电活性材料性能提高了约50%,这种材料有望应用于制动器、感应器等领域.%The cellulose/poly (hydroxybutyrate)(PHB) electroactive composite membranes were prepared by dissolving cotton cellulose and PHB powder in trifluoroacetic acid (TFA),followed by solution casting.The characteristics of the cellulose/PHB electroactive composite membrane were investigated by SEM,FT-IR,DSC and XRD.The mechanical and electroactive performance of the cellulose/PHB electroactive composite membrane were tested.The results indicate that the crystallinity index of cellulose in the composite membrane calculated based on XRD pattern decreases about 29 % compared with that of pure cellulose membrane.The tensile strength,elongation at break and Young's modulus of the cellulose/PHB electroactive composite membrane are 74MPa,7.2% and 2.5GPa,respectively,which increase greatly compared with of pure PHB.The bending displacement of the cellulose/PHB electroactive composite membrane can achieve 1.35 cm,increases by 50 % compared with that of pure cellulose membrane.These cellulose/PHB electroactive composite membranes might have potential applications in the field of actuator,sensor etc.

  16. Solid-phase assay for the phosphorylation of proteins blotted on nitrocellulose membrane filters

    International Nuclear Information System (INIS)

    A new procedure for the phosphorylation and assay of phosphoproteins is described. Proteins are solubilized from tissue samples, separated by polyacrylamide gel electrophoresis, transferred onto nitrocellulose membrane filters, and the blotted polypeptides are phyosphorylated with the catalytic subunit of cyclic AMP (adenosine 3':5'-monophosphate)-dependent protein kinase. The method was developed for the assay of dephosphosynapsin I, but it has also proven suitable for the phosphorylation of other proteins. The patterns of phosphorylation of tissue samples phosphorylated using the new method are similar to those obtained using the conventional test tube assay. Once phosphorylated, the adsorbed proteins can be digested with proteases and subjected to phosphopeptide mapping. The phosphorylated blotted proteins can also be analyzed by overlay techniques for the immunological detection of polypeptides

  17. 均质纤维素膜的制备及其正渗透性能研究%Preparation and performance of homogeneous cellulose forward osmosis membrane

    Institute of Scientific and Technical Information of China (English)

    张兵涛; 张林; 黄和; 侯立安

    2014-01-01

    以纤维素(cellulose)为膜材料,离子液体1-乙基-3甲基咪唑醋酸盐(EMIMAc)为溶剂,水为非溶剂,无纺布作为支撑层,通过相转化法制备了纤维素均质膜。采用红外、X-射线衍射和扫描电子显微镜表征了膜的结构及形貌,考察了该膜的正渗透性能。结果表明:纤维素溶解再生过程中没有发生化学变化,但晶型发生了转变;当原料液为0.6 mol/L的氯化钠水溶液,汲取液为特制的营养液时,所制备的正渗透膜的水通量为3.534 L/(m2· h),截盐率达到99%以上。%The-nonporous-homogeneous-cellulose-membrane-for-forward-osmosis-was-pre-pared-via-phase-inversion-method-using-ionic-liquid-1-ethyl-3-methyl-imidazolium-acetate-(EMI-MAc)-as-solvent,water-as-nonsolvent-on-a-non-woven-fabric-substrate.-The-characterizations-of-Fourier-transform-infrared-(FTIR)-and-X-ray-diffraction-(XRD)-spectroscopies-showed-that-no-obvious-change-occurred-in-the-chemical-structure-of-cellulose-after-membrane-formation,but-the-crystallinity-had-a-certain-degree-of-decline.-The-cross-section-and-the-surface-morphologies-of-the-cellulose-forward-osmosis-membrane-were-analyzed-by-scanning-electron-microscopy-(SEM).-The-membrane-performance-were-investigated-by-measuring-water-flux-and-rejection-of-simulated-seawater.-The-water-flux-of-the-cellulose-forward-osmosis-membrane,which-the-cellu-lose-concentration-is-8%(wt)-in-casting-solution,was-3.534-L/m2-·-h-and-the-rejection-for-NaCl-was-more-than-99%,using-0.6-mol/L-NaCl-solution-as-the-feed-solution-and-lab-made-nutrient-solution-as-the-draw-solution.

  18. Filtration through nylon membranes negatively affects analysis of arsenic and phosphate by the molybdenum blue method

    DEFF Research Database (Denmark)

    Heimann, Axel Colin; Jakobsen, Rasmus

    2007-01-01

    Filtering synthetic arsenic- or phosphate-containing solutions (1.5-47.6 mu mol/L) with nylon syringe filters significantly reduced absorbances (by 6-74%) when analyzed with the colorimetric molybdenum blue method. Filtering the same solutions with cellulose acetate syringe filters yielded...... no significant differences as compared to unfiltered controls. The detrimental effect of nylon membranes was also observed when pure Milli-Q water was filtered and Subsequently spiked with arsenic(III) or phosphate suggesting that some compound(s) eluting from the filter membranes interfere with the color...

  19. In vitro phonophoresis: effect of ultrasound intensity and mode at high frequency on NSAIDs transport across cellulose and rabbit skin membranes.

    Science.gov (United States)

    Meshali, M M; Abdel-Aleem, H M; Sakr, F M; Nazzal, S; El-Malah, Y

    2008-01-01

    The objective of this study was to evaluate the effect of intensity, mode, and duration of ultrasound application on the transport of three nonsteroidal anti-inflammatory drugs (NSAIDs) across cellulose membrane and rabbit-skin. Ibuprofen, piroxicam and diclofenac sodium were used as the model drugs. Studies were performed in vitro using a modified Franz diffusion assembly adapted to a therapeutic ultrasound transducer. Ultrasound had a significant and positive effect on the transport of the model NSAIDs across cellulose and rabbit skin membranes. Increasing ultrasound intensity from 0.5 to 3.0 W/cm2 led to a proportional increase in drug transport. Continuous ultrasound mode was more effective in enhancing drug transport than the pulsed mode. Diclofenac sodium had the least flux and permeability coefficient. This was attributed to its comparatively lower pKa value that renders the drug more ionizable in the buffer solution, consequently reducing its selective penetration through the membranes. This study demonstrated the therapeutic potential of ultrasound in transdermal delivery of NSAIDs and the synergistic effect of temperature and ultrasound operational parameters on drug transport. PMID:18271303

  20. Electrochemical Properties of LLTO/Fluoropolymer-Shell Cellulose-Core Fibrous Membrane for Separator of High Performance Lithium-Ion Battery

    Directory of Open Access Journals (Sweden)

    Fenglin Huang

    2016-01-01

    Full Text Available A superfine Li0.33La0.557TiO3 (LLTO, 69.4 nm was successfully synthesized by a facile solvent-thermal method to enhance the electrochemical properties of the lithium-ion battery separator. Co-axial nanofiber of cellulose and Poly(vinylidene fluoride-co-hexafluoropropylene (PVDF-HFP was prepared by a co-axial electrospinning technique, in which the shell material was PVDF-HFP and the core was cellulose. LLTO superfine nanoparticles were incorporated into the shell of the PVDF-HFP. The core–shell composite nanofibrous membrane showed good wettability (16.5°, contact angle, high porosity (69.77%, and super electrolyte compatibility (497%, electrolyte uptake. It had a higher ionic conductivity (13.897 mS·cm−1 than those of pure polymer fibrous membrane and commercial separator. In addition, the rate capability (155.56 mAh·g−1 was also superior to the compared separator. These excellent performances endowed LLTO composite nanofibrous membrane as a promising separator for high-performance lithium-ion batteries.

  1. PHOTOCATALYTIC ACTIVITY OF TiO2 NANO SUPPORTED ON MEMBRANE CELLULOSE ACETATE/NATA DE COCO (CA/NDC IN PHOTODEGRADATION OF METHYLENE BLUE

    Directory of Open Access Journals (Sweden)

    Roro Ernia Prawithasari

    2015-12-01

    Full Text Available Study of synthesis and effectiveness of membrane catalyst of cellulose acetate/nata de coco-TiO2 nano (CA/NDC-TiO2 nano in photodegradation of methylene blue in batch system has been investigated. TiO2nanoparticles were synthesized by hydrothermal method followed by calcination at 450oC. Scanning Electron Microscopy (SEM images indicate nano TiO2 has been successfully synthesized with average particle diameter as 88,63±4,37 nm. X-ray diffraction pattern (XRD of nano TiO2 shows some characteristic peaks of anatase TiO2 were still existed. Membrane photocatalyst of CA/NDC- nano TiO2 was prepared via phase inversion method by mixing TiO2 nanoparticles with CA casting solution. Thermogravimetric analysis shows three decomposition steps of CA/NDC-nano membrane as well as CA/NDC membrane. Photodegradation of methylene blue was conducted with nano-TiO2 particles and CA/NDC-TiO2 membrane for 50 minutes in batch system. The absorbance changes were measured by spectrophotometer at wavelength of 664.6 nm. The result shows the photodegradation rections tended to follow second order reaction. According to the rate constant value, k, the photocatalytic effectivity using CA-NDC/nano TiO2 membrane and nano TiO2photocatalysts in metilen blue photodegradation, statistically were not significantly different.

  2. Gypsum (CaSO4·2H2O Scaling on Polybenzimidazole and Cellulose Acetate Hollow Fiber Membranes under Forward Osmosis

    Directory of Open Access Journals (Sweden)

    Tai-Shung Chung

    2013-11-01

    Full Text Available We have examined the gypsum (CaSO4·2H2O scaling phenomena on membranes with different physicochemical properties in forward osmosis (FO processes. Three hollow fiber membranes made of (1 cellulose acetate (CA, (2 polybenzimidazole (PBI/polyethersulfone (PES and (3 PBI-polyhedral oligomeric silsesquioxane (POSS/polyacrylonitrile (PAN were studied. For the first time in FO processes, we have found that surface ionic interactions dominate gypsum scaling on the membrane surface. A 70% flux reduction was observed on negatively charged CA and PBI membrane surfaces, due to strong attractive forces. The PBI membrane surface also showed a slightly positive charge at a low pH value of 3 and exhibited a 30% flux reduction. The atomic force microscopy (AFM force measurements confirmed a strong repulsive force between gypsum and PBI at a pH value of 3. The newly developed PBI-POSS/PAN membrane had ridge morphology and a contact angle of 51.42° ± 14.85° after the addition of hydrophilic POSS nanoparticles and 3 min thermal treatment at 95 °C. Minimal scaling and an only 1.3% flux reduction were observed at a pH value of 3. Such a ridge structure may reduce scaling by not providing a locally flat surface to the crystallite at a pH value of 3; thus, gypsum would be easily washed away from the surface.

  3. Point-of-use filter membrane selection, start-up, and conditioning for low-defect photolithography coatings

    Science.gov (United States)

    Brakensiek, Nick; Cronin, Michael

    2013-03-01

    Recent innovations in device design, including FinFETs and metal gate technologies, have required similar innovation in lithographic materials and process development. Complex processes such as double patterning and multilayer imaging require new and novel material chemistries to meet the rigorous defect level requirements for successful yield. To address these complex processes, new materials for multilayer imaging, including spin-on hardmask layers and thick carbon underlayers, have been introduced. These two types of materials have different roles in the multilayer imaging scheme, and likewise the chemistries that are used in these materials are different. To evaluate the wide variety of materials, it is necessary to be able to install them on a coater-track quickly and efficiently and to ensure that the chosen filter uses the best available filtration settings to provide the best-performing material. Typically end users of point-of-use filters will install a new filter, which will be primed with the best-known method, and purge chemical until a defect baseline is reached. This study examines the interaction between a spin-on hardmask chemistry and membrane materials, examining decreasing pore size and the differential pressure increases. Under these conditions, known issues with particles, microbubbles, or oddly timed defect excursions should be able to be avoided with the proper selection and start-up of the filter. An Entegris IntelliGen® Mini dispense system with Impact® 2 filters was used to test different filtration settings on various filtration membranes and determine the best settings for each membrane type. These pumps have the capability to control differential pressure across the filter based upon its operating parameters. Results of this investigation will show that for the spin-on hardmask material, optimizing differential pressure across the filter by adjusting the IntelliGen® Mini operating parameters will ultimately reduce blanket coat defect

  4. Activated sludge filterability improvement by nitrifying bacteria abundance regulation in an adsorption membrane bioreactor (Ad-MBR).

    Science.gov (United States)

    Sun, Fei-yun; Lv, Xiao-mei; Li, Ji; Peng, Zhong-yi; Li, Pu; Shao, Ming-fei

    2014-10-01

    Autotrophic nitrifying bacteria have its intrinsic properties including low EPS production, dense colonial structure and slow-growth rate, favoring the sludge filterability improvement. An adsorption-MBR (Ad-MBR) was developed to enrich nitrifier abundance in the MBR chamber by inlet C/N regulation, and its possible positive effect on sludge filterability and underlying mechanisms were investigated. By DNA extraction, PCR amplification and Illumina high-throughput pyrosequencing, the abundance of nitrifying bacteria was accurately quantified. More than 8.29% nitrifier abundance was achieved in Ad-MBR sludge, which was above three times of that in conventional MBR. Regulated C/N ratio and thereafter nitrifier abundance enrichment improved sludge filterability by altering sludge mixture and its supernatant properties, reflected by a good sludge settleability, a low supernatant viscosity and turbidity, a low supernatant organic substances concentration, and a small amount of strong hydrophobic fractional components, thus to profoundly improve sludge filterability and decelerate membrane fouling. PMID:25146315

  5. Characterization of Cellulose Synthesis in Plant Cells

    OpenAIRE

    Samaneh Sadat Maleki; Kourosh Mohammadi; Kong-shu Ji

    2016-01-01

    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...

  6. Crosslinking of Kapok Cellulose Fiber via Azide Alkyne Click Chemistry as a New Material for Filtering System: A Preliminary Study

    Directory of Open Access Journals (Sweden)

    Nur Syazwani Abd Rahman

    2016-01-01

    Full Text Available A new class of green material has been elaborated by grafting the modified kapok fiber, by the means of azidated kapok fiber followed by “click-chemistry” reaction with the terminal alkyne crosslinker. The modified and synthesized product was characterized using Fourier transform infrared spectroscopy (FT-IR, and Scanning electron microscopy (SEM. The study also was undertaken to investigate the effect on the absorption of methylene blue from aqueous solution onto the click fiber prepared. The findings showed that the click kapok absorbed more compared to the untreated kapok. Based on the result, the reaction of click chemistry influenced the properties of the filter made from kapok fiber.

  7. Filtering Surface Water with a Polyurethane-based Hollow Fiber Membrane:Effects of Operating Pressure on Membrane Fouling

    Institute of Scientific and Technical Information of China (English)

    赵学辉; 张宏伟; 王捷

    2014-01-01

    Membrane fouling seriously restricts applications of membrane technology. A novel strategy was ap-plied in this study to retard membrane fouling by changing operating pressure with the pressure responsibility membrane. A polyurethane-based hollow fiber membrane was used to treat surface water for evaluating the effect of operating pressure on membrane fouling. Some bench-scale tests in dead-end mode were carried out. In the experi-ments without backwashing, as operating pressure increased, severe membrane fouling occurred on membrane sur-face, while the permeate quality was improved obviously, which is considered to be due to shrinkage deformation. The total resistance, irreversible resistance and reversible resistance under different backwash pressures were de-termined in filtration/backwashing test. With the increase of backwash pressure, the total resistance decreased, and more importantly, the irreversible resistance also decreased, which implies that small particles deposited inside membrane pores and cake layers on membrane surface are effectively removed. Similar results could be obtained in mass balance tests. The results of the present study indicate that the application of pressure responsibility membrane in surface water treatment may be an effective strategy for reducing membrane fouling.

  8. A Pole-Zero Filter Cascade Provides Good Fits to Human Masking Data and to Basilar Membrane and Neural Data

    Science.gov (United States)

    Lyon, Richard F.

    2011-11-01

    A cascade of two-pole-two-zero filters with level-dependent pole and zero dampings, with few parameters, can provide a good match to human psychophysical and physiological data. The model has been fitted to data on detection threshold for tones in notched-noise masking, including bandwidth and filter shape changes over a wide range of levels, and has been shown to provide better fits with fewer parameters compared to other auditory filter models such as gammachirps. Originally motivated as an efficient machine implementation of auditory filtering related to the WKB analysis method of cochlear wave propagation, such filter cascades also provide good fits to mechanical basilar membrane data, and to auditory nerve data, including linear low-frequency tail response, level-dependent peak gain, sharp tuning curves, nonlinear compression curves, level-independent zero-crossing times in the impulse response, realistic instantaneous frequency glides, and appropriate level-dependent group delay even with minimum-phase response. As part of exploring different level-dependent parameterizations of such filter cascades, we have identified a simple sufficient condition for stable zero-crossing times, based on the shifting property of the Laplace transform: simply move all the s-domain poles and zeros by equal amounts in the real-s direction. Such pole-zero filter cascades are efficient front ends for machine hearing applications, such as music information retrieval, content identification, speech recognition, and sound indexing.

  9. Quantitative structure-activity relationship (QSAR) analysis of surfactants influencing attachment of a Mycobacterium sp. to cellulose acetate and aromatic polyamide reverse osmosis membranes.

    Science.gov (United States)

    Campbell, P; Srinivasan, R; Knoell, T; Phipps, D; Ishida, K; Safarik, J; Cormack, T; Ridgway, H

    1999-09-01

    A series of 23 neutral, anionic, and zwitterionic surfactants were tested at a concentration of 0.1% wt/vol for their influence on attachment of a Mycobacterium sp. to cellulose acetate (CA) and polyamide (PA) reverse osmosis (RO) membranes. Four cell attachment bioassays were used: (1) semiconcurrent addition of surfactant and bacteria to RO coupons (standard assay); (2) surfactant pretreatment of RO membranes (membrane pretreatment assay); (3) surfactant treatment of adsorbed cells (detachment assay); and (4) surfactant pretreatment of mycobacteria (cell pretreatment assay). Seventeen surfactants inhibited attachment to PA membranes, whereas 15 inhibited attachment to CA in standard assays and, in 13 cases, the same surfactant inhibited attachment to both PA and CA. Despite greater cell attachment to PA than CA, surfactants were typically more effective in the former membrane system. More surfactants were effective in impairing cell attachment than in promoting detachment and a number enhanced attachment in membrane pretreatment assays, suggesting surface modification of RO membranes. Cell pretreatment inhibited attachment to CA membranes, suggesting the bacterial surface was also a target for detergent activity. Multivariate regression and cluster analyses indicated that critical micellar concentration (CMC) was positively correlated with Mycobacterium attachment in CA and PA standard assays. Surfactant dipole moment and octanol/water partitioning (LogP) also contributed to detergent activity in the PA system, whereas dipole moment, molecular topology (i.e., connectivity indices), and charge properties influenced activity in the CA system. Influential variables in membrane pretreatment assays included the LogP, topology indices, and charge properties, whereas CMC played a diminished role. Surfactant dipole moment was most influential in CA membrane detachment assays. Increasing system ionic strength by LiBr addition strengthened inhibition of cell attachment to

  10. Use of cloth-media filter for membrane bioreactor treating municipal wastewater.

    Science.gov (United States)

    Zahid, Waleed M; El-Shafai, Saber A

    2011-02-01

    This study evaluated three different textile materials (Acrylate, Polyester, and Nylon) as filter media for MBR treating municipal wastewater. Chemical oxygen demand (COD) loading rates were 1.71, 1.65 and 1.84 g/l d while feed/microorganisms (F/M) ratios were 0.32, 0.31 and 0.33 in Reactor 1, Reactor 2 and Reactor 3, respectively. The actual hydraulic retention times were 8.6, 8.9 and 8.0 h in R1, R2 and R3. At 5.3-5.5 g/l mixed liquor suspended (MLSS) and 26.3 days solid retention time (SRT) the membrane bioreactors were effective in removing 93-95% of COD, 99% of total suspended solids (TSS) and turbidity, 89-94% of total kjeldahl nitrogen (TKN) and 90-96% of total ammonia nitrogen. Phosphorous removal was limited to 51-55% while faecal coliform was reduced by four logs. Quality of the treated effluents met both Saudi and Egyptian reuse standards for restricted irrigation and could be easily disinfected to meet the unrestricted irrigation standards. PMID:20965722

  11. Hot gas cleanup using ceramic cross flow membrane filters. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Ciliberti, D.F.; Smeltzer, E.E.; Alvin, M.A.; Keairns, D.L.; Bachovchin, D.M.

    1983-12-01

    The single unresolved technical issue in the commercialization of pressurized fluid-bed combustion (PPBC) for electric power production is the hot gas cleaning problem. In this technology, high-temperature and -pressure (HTHP), dust-laden flue gases from the combustor must be cleaned enough to reduce expansion turbine blade erosion to an economically acceptable level. Additionally, the level of particulate emission must be compatible with the New Source Performance Standards (NSPS) for environmental acceptability. The Department of Energy (DOE) has sponsored a wide range of research and development programs directed at the solution of this problem. These programs were divided into two classifications, one dealing with more advanced concepts where testing was to be done at relatively large scale and a second group of less advanced, novel concepts where the testing was to be carried out at a bench scale. The cross-flow ceramic membrane filter program described in this report is a member of the small-scale, novel concept group.

  12. Sr/Y separation by supported liquid membranes based on nuclear track micro filters

    International Nuclear Information System (INIS)

    First results of experiments concerning the preparation of a Y-90 generator are presented. The aim of this work is to prepare a rather cost-effective and easy to maintain Y-90 generator that produces Y-90 solutions of sufficient purity for their subsequent application in radionuclide therapy. Besides the need for high purity of the Y-90 solutions, it has to be taken into account that high activities are involved (up to 2 Ci Sr-90). Consequently, materials with very good radiation stability must be used for the construction of the generator. Nuclear track micro filters (NTMFs) prepared from polyimide foils are renowned for their outstanding radiolytical and chemical stability. In addition to that they have the distinct advantage that pore size and porosity can be chosen and optimized for each application. The NTMFs are used as supported liquid membranes (SLM) after impregnating them with a 1:1 mixture of bis-(2-ethylhexyl)-phosphate (HDEHP) and tributylphosphate (TBP). Y-90 separation from its parent Sr-90 is achieved by its selective transport through the pores of the impregnated NTMF. The Y-90 activity of the prepared solutions is determined by means of Cerenkov-counting, the Sr-90 content is calculated after determining the activity of an internal standard, namely Sr-85, by low-level gamma-spectrometry. It was shown that a separation of Y-90 and Sr-90 using NTMFs impregnated with an appropriate extractant is possible

  13. Micromachining of large area amorphous carbon membranes prepared by filtered cathodic vacuum arc technique

    Science.gov (United States)

    Liujiang, Yu; Tay, B. K.; Sheeja, D.; Fu, Y. Q.; Miao, J. M.

    2004-02-01

    Currently, there is a strong drive to make micro-electro-mechanical system (MEMS) devices from higher performance materials such as diamond-like carbon or amorphous carbon (a-C) films, due to their excellent tribological properties, low-stiction (hydrophobic) surfaces, chemical inertness and high elastic modulus, compared to that of Si. The hydrogen free a-C films prepared, by Nanyang Technological University's (NTUs) patented filtered cathodic vacuum arc (FCVA) technique, at 100 eV exhibits high fraction of tetrahedral (sp 3 bonded) carbon atoms. These films exhibit relatively high hardness, stiffness and wear resistance in addition to low friction and stiction behaviour. However, the primary problem lies in the large intrinsic compressive stress induced during the deposition process. By making use of high substrate pulse bias, we have successfully produced low stress, thick a-C films. The films were then characterised using different equipments to evaluate the stress, microstructure and morphological roughness. Large area a-C membranes, of 2 mm×2 mm in size, have also been fabricated using the low stress, thick film deposited by the above method.

  14. Micromachining of large area amorphous carbon membranes prepared by filtered cathodic vacuum arc technique

    Energy Technology Data Exchange (ETDEWEB)

    Liujiang, Yu; Tay, B.K.; Sheeja, D.; Fu, Y.Q.; Miao, J.M

    2004-02-29

    Currently, there is a strong drive to make micro-electro-mechanical system (MEMS) devices from higher performance materials such as diamond-like carbon or amorphous carbon (a-C) films, due to their excellent tribological properties, low-stiction (hydrophobic) surfaces, chemical inertness and high elastic modulus, compared to that of Si. The hydrogen free a-C films prepared, by Nanyang Technological University's (NTUs) patented filtered cathodic vacuum arc (FCVA) technique, at 100 eV exhibits high fraction of tetrahedral (sp{sup 3} bonded) carbon atoms. These films exhibit relatively high hardness, stiffness and wear resistance in addition to low friction and stiction behaviour. However, the primary problem lies in the large intrinsic compressive stress induced during the deposition process. By making use of high substrate pulse bias, we have successfully produced low stress, thick a-C films. The films were then characterised using different equipments to evaluate the stress, microstructure and morphological roughness. Large area a-C membranes, of 2 mmx2 mm in size, have also been fabricated using the low stress, thick film deposited by the above method.

  15. Analysis of diazinon pesticide using potentiometric biosensor based on enzyme immobilized cellulose acetate membrane in gold electrode

    Science.gov (United States)

    Mashuni; Ramadhan, L. O. A. N.; Jahiding, M.; Herniati

    2016-02-01

    Biosensor for analysis of diazinon pesticide using Potentiometric transducer has been developed. The basic element of this biosensor was a gold electrode modified with an immobilized acetylcholinesterase enzyme layer formed by entrapment with glutaraldehyde crosslinked-cellulose acetate. The aim of the research is to determine the composition of glutaraldehyde crosslinked-cellulose acetate in the gold electrode which provide optimum performance of biosensors of diazinon pesticide analysis on characterization include a range of working concentration, sensitivity, and detection limit. The results showed the composition of the cellulose acetate 15% and glutaraldehyde 25% that obtain optimum performance in the measurement of diazinon pesticide with a range of working concentration of 10-6 ppm to 1 ppm, the value of sensitivity 20.275 mV/decade and detection limit 10-6 ppm. The use of cellulose acetate provides highly sensitive devices allowing the efficient analysis of pesticides. The response time of electrode is on the measurement of pesticide diazinon with concentration variation of 10-6 ppm to 1 ppm with response time is about 5 minutes.

  16. Cyclic AMP--dependent aggregation of Swiss 3T3 cells on a cellulose substratum (Cuprophan) and decreased cell membrane Rho A.

    Science.gov (United States)

    Faucheux, N; Nagel, M D

    2002-06-01

    Cell surface integrin receptors and Rho family GTPases function together to mediate adhesion-dependent events in cells. We have shown that the attachment of Swiss 3T3 cells to a cellulose substratum (Cuprophan, CU) activates adenylyl cyclase, which catalyses cyclic AMP (cAMP) production. CU adsorbs vitronectin poorly, prevents cell spreading and causes cells to aggregate. By contrast, spread cells on polystyrene (PS) contain low cAMP concentrations. We have now investigated the shift between integrin signalling-Rho A and the cAMP pathway. CU did not support the formation of focal contacts and stress fibres. The plasma membranes of cells on CU had less Rho A than those of cells on PS. Also, blocking vitronectin (VN) or fibronectin (FN)-integrin receptors with echistatin, which activates cAMP production, decreased Rho A in the plasma membrane of cells attached to PS. But adsorption of VN or FN onto CU, which limits the production of the cAMP, increased the cell membrane Rho A. Adding an inhibitor of cAMP-dependent protein kinase PKA to the medium also increased the plasma membrane Rho A in aggregated cells attached to CU. These results highlight the importance of cAMP, generated by cell attachment to substratum, as a gating element in integrin-Rho A signalling. PMID:12013176

  17. Evaluation of the Hydrophobic Grid Membrane Filter for the Enumeration of Moulds and Yeasts in Naturally-Contaminated Foods

    OpenAIRE

    V.H. Tournas

    2009-01-01

    Over 240 food samples from six food groups (tree nuts, grains and grain products, dried fruits, fresh produce, fruit juice, and dairy products) were tested for levels of fungal contamination using the NEO-GRID hydrophobic grid membrane filter (HGMF) and the FDA official (BAM) method. Results showed that HGMF performed very well for all tested commodities giving yeast and mould (YM) counts similar to those of the BAM (reference) method. Statistical analysis of the data (t-test) revealed no sig...

  18. 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. PMID:26799780

  19. Para-aminobenzamidine linked regenerated cellulose membranes for plasminogen activator purification: Effect of spacer arm length and ligand density

    Science.gov (United States)

    Fasoli, Ezio; Reyes, Yiaslin Ruiz; Guzman, Osiris Martinez; Rosado, Alexandra; Cruz, Vivian Rodriguez; Borges, Amaris; Martinez, Edmarie; Bansal, Vibha

    2013-01-01

    Despite membrane-based separations offering superior alternative to packed bed chromatographic processes, there has been a substantial lacuna in their actual application to separation processes. One of the major reasons behind this is the lack of availability of appropriately modified or end-group modifiable membranes. In this paper, an affinity membrane was developed using a commercially available serine protease inhibitor, para-aminobenzamidine (pABA). The membrane modification was optimized for protein binding capacity by varying: i) the length of the spacer arm (SA; 5-atoms, 7-atoms, and 14-atoms) linking the ligand to membrane surface; ii) the affinity ligand (pABA) density on membrane surface (5–25 nmoles per cm2). Resulting membranes were tested for their ability to bind plasminogen activators (PAs) from mono- and multi- component systems in batch mode. The membrane containing pABA linked through 7-atoms SA but similar ligand density as in the case of 5- or 14- atoms long SA was found to bind up to 1.6-times higher amounts of PA per nmole of immobilized ligand from conditioned HeLa cell culture media. However, membranes with similar ligand densities but different lengths of SA, showed comparable binding capacities in monocomponent system. In addition, the length of SA did not affect the selectivity of the ligand for PA. A clear inverse linear correlation was observed between ligand density and binding capacity until the point of PA binding optima was reached (11±1.0 nmoles per cm2) in mono- and multi- component systems for 7- as well as 14- atoms SA. Up to 200-fold purification was achieved in a single step separation of PA from HeLa conditioned media using these affinity membranes. The issues of ligand leaching and reuse of the membranes were also investigated. An extensive regeneration procedure allowed the preservation of approximately 95% of the PA binding capacity of the membranes even after five cycles of use. PMID:23703544

  20. Enzymatic hydrolysis of cellulose: Study of the process of recovery of cellulose glucides by the technique of hyperfiltration on polysulphonic membranes. Idrolisi enzimatica della cellulosa. Studio del processo di recupero dei glucidi da cellulasi con tecniche di ultrafiltrazione su membrane polisolfoniche

    Energy Technology Data Exchange (ETDEWEB)

    Pizzichini, M.; Fabiani, C.; Sperandei, M.

    1986-07-01

    Membrane separation technology can optimize some steps of cellulose enzymatic hydrolysis process. In order to continuously remove glucose and cellobiose in the permeate solution and recover the enzymes in the recycling stream, the separation by ultrafiltration of glucides from enzymes was studied. Celluclast enzyme supplied by Novo,in aqueous buffer solution at pH5 and concentration of 0.2-4% w/v range, was used as a feed. Glucides concentration was in the 0.02-0,95% w/v$range. A DDS UF System (Lab Unit-20) was employed with 16 flat membranes type GS81PP with cut off at 6000 dalton. During the separation test, a reduction in the permeate flux caused by protein deposition on the membrane surface was observed. Water washing of the membranes cleans all the membranes package and the original membranes permeability (80 1/sq. m/h at 4 bars) is recovered. Glucides can be quantitatively recovered by the UF process. However the high cellulase concentration may produce a slight enzyme inactivation (2-9%).

  1. Determination of water-insoluble light absorbing matter in rainwater using polycarbonate membrane filters and photometric detection

    Directory of Open Access Journals (Sweden)

    J. E. Engström

    2009-02-01

    Full Text Available A method for determination of water-insoluble light absorbing matter in rainwater has been developed. After collection the rainwater samples were filtered using polycarbonate membrane filter in the laboratory. After drying the filter in filtered air, the amount of water-insoluble light absorbing matter (soot on the filters was determined with photometry at a wavelength of 555 nm. The precision for the method was better than 10% calculated as relative standard deviation. The overall loss of soot due to adsorption during collection and filtration was 22±2%. The detection limit was estimated to 0.025 in optical density, or 2 ng/ml expressed as a concentration assuming a filtration volume of 30 ml. Analysis of environmental samples have been successfully performed with the described method at the Maldives Climate Observatory Hanimaadhoo and Nepal Climate Observatory. At Maldives the average soot concentration in rain was 0.048 μg/ml and at the Nepal obseravtory 0.086 μg/ml.

  2. Collagen-graft mixed cellulose esters membrane maintains undifferentiated morphology and markers of potential pluripotency in feeder-free culture of induced pluripotent stem cells.

    Science.gov (United States)

    Lotfalah Moradi, Sadegh; Hajishafieeha, Zahra; Nojedehi, Shahrzad; Dinarvand, Vida; Hesami Tackallou, Saeed; Roy, Ram V; Ardeshirylajimi, Abdolreza; Soleimani, Masoud

    2016-09-01

    Induced pluripotent stem cells (iPSCs) are unique and unlimited clinical sources of stem cell therapy for the regenerative medicine. Feeder layer preparation is an important step for iPSCs production, which is expensive, time-consuming and requires conversance. In the present study, we investigated the maintenance of pluripotency, and stemness of the iPSCs through feeder-free culture on a collagen-grafted Mixed Cellulose Esters membrane (MCE-COL) after three passages during twelve days. Results have demonstrated that the iPSCs cultured on MCE-COL membrane had a fine, typical undifferentiated morphology, increased proliferation rate and significant multi-lineage differentiation potential. Alkaline phosphatase (ALP) staining and pluripotency associated gene markers expression further confirmed that iPSCs cultured on the surface of MCE-COL had more ALP positive colonies and enhanced expression of Oct-4, Nanog, Sox-2 and ALP in comparison with MCE and control groups. Since MCE-COL membrane has three dimensional structure and bioactivity, it has the potential for usage in the feeder-free culture of iPSCs, and could be a suitable candidate to use as a feeder layer in stem cells preparation. PMID:27449919

  3. 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)

  4. Bacterial cellulose/boehmite composites

    International Nuclear Information System (INIS)

    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)

  5. 甲基纤维素对SiO2薄膜性能的影响%Effect of methyl cellulose on the properties of silica membrane

    Institute of Scientific and Technical Information of China (English)

    同帜; 韩丹丹; 李大川; 崔双科

    2013-01-01

    以正硅酸乙酯为主要原料,采用溶胶凝胶法和浸渍提拉技术在氧化铝支撑体上进行涂膜,研究了在制备过程中引入甲基纤维素(MC)对SiO2薄膜性能的影响.采用FT-IR和AFM、BET等测试技术对膜的热稳定性、凝胶膜热处理前后的结构变化和薄膜的表面微观形貌进行表征.实验结果表明,甲基纤维素对SiO2溶胶体系起到增稠剂的作用,本次实验确定的最佳加入量为每100 mL溶胶中加入0.35g甲基纤维素;SiO2薄膜表面光滑平整,内部结构均匀,具有良好的热稳定性;但与未加入甲基纤维素的薄膜相比较,薄膜的孔隙率和平均孔径均有一定的减少;SiO2薄膜的孔径分布呈单峰且较窄,其最可几孔径为1.14 nm;添加甲基纤维素后的薄膜在0.18 MPa下,纯水通量为880 L/(m2·h);孔隙率约为31%,体积密度为2.4%.%A silica gel was prepared on the supporting body of alumina by sol-gel process and dip-coating technique using tetraethoxy silicone(TEOS) as main raw material, then a SiO2membrane was introducted by methyl cellulose. The structures and properties were effected by adding methyl cellulose. The thermal stability, phase transformation, structure and morphology of composite membranes were characterized by FT-IR、AFM、 BET, etc. respectively. The results showed that the methyl cellulose played a role of thickening agent on SiO2 sol system. When the SiO2 sol was 100 mL, the optimum adding amount of methyl cellulose was 0.35 g. The films surface was smooth, uniform internal structure and had good thermal stability. The porosity and average pore size of the thin film can be reduced compared with that there is no adding methyl cellulose film; The pore size distribution of SiO2films were unimodal, narrow and the most probable pore diameters were about 1. 14 nm; The pure water flux of the film added was 880 L/ (m2 · h); porosity was about 31%, and volume density was 2. 4% under 0. 18 MPa.

  6. The cellulose synthase companion proteins act non-redundantly with CELLULOSE SYNTHASE INTERACTING1/POM2 and CELLULOSE SYNTHASE 6

    OpenAIRE

    Endler, Anne; Schneider, Rene; Kesten, Christopher; Edwin R Lampugnani; Persson, Staffan

    2016-01-01

    ABSTRACT Cellulose is a cell wall constituent that is essential for plant growth and development, and an important raw material for a range of industrial applications. Cellulose is synthesized at the plasma membrane by massive cellulose synthase (CesA) complexes that track along cortical microtubules in elongating cells of Arabidopsis through the activity of the protein CELLULOSE SYNTHASE INTERACTING1 (CSI1). In a recent study we identified another family of proteins that also are associated ...

  7. Efficiency of Sampling and Analysis of Asbestos Fibers on Filter Media: Implications for Exposure Assessment

    Science.gov (United States)

    To measure airborne asbestos and other fibers, an air sample must represent the actual number and size of fibers. Typically, mixed cellulose ester (MCE, 0.45 or 0.8 µm pore size) and to a much lesser extent, capillary-pore polycarbonate (PC, 0.4 µm pore size) membrane filters are...

  8. SURFACE MODIFICATION OF SILICA- AND CELLULOSE-BASED MICROFILTRATION MEMBRANES WITH FUNCTIONAL POLYAMINO ACIDS FOR HEAVY METAL SORPTION

    Science.gov (United States)

    Functionalized membranes represent a field with multiple applications. Examination of specific metal-macromolecule interactions on these surfaces presents an excellent method for characterizion of these materials. These interactions may also be exploited for heavy metal sorptio...

  9. Filtration efficiency and filter resistance of nylon-6 and nylon-6/chitosan nanofibrous membranes

    OpenAIRE

    Panu Danwanichakul; Duangkamol Danwanichakul; Adisara Yooyanyong; Kantika Sae-Ieo

    2016-01-01

    Pore size reduction of nanofibrous membranes and the removal efficiencies for submicron PS particles (410, 200, 90 and 50 nm) were investigated in this study. Blending chitosan with nylon-6 generated ultrafine fibers among typical nanofibers which could yield an electrospun membrane with smaller average pore size. It was found that high molecular weight chitosan could increase the filtration efficiency better than low molecular weight chitosan. The best membrane was obtained from solution of ...

  10. Preparation and properties of cellulose triacetate forward osmosis membrane%三乙酸纤维素正渗透膜的制备与性能

    Institute of Scientific and Technical Information of China (English)

    解利昕; 辛婧; 解奥

    2014-01-01

    Cellulose triacetate based membranes for forward osmosis were prepared by immersion precipitation. The polymer solution consisted of cellulose triacetate as the membrane material, 1,4-dioxane and acetone as solvent,methanol and lactic acid as additives. Casting composition and preparation conditions-1,4-dioxane/acetone ratio,lactic acid content,evaporation time,casting thickness and annealing temperature-were tested for their effects on membrane performance. The optimized membrane showed 14.10L/(m2·h) water flux and 0.031mol/(m2·h) reverse solute flux using a feed solution of pure water and draw solution of 0.56mol/L CaCl2. When 0.1mol/L NaCl was used as the feed solution and 4mol/L glucose was used as the draw solution,water flux was above 5L/(m2·h) and rejection for NaCl was above 99%. The optimized membrane had a more hydrophilic surface, higher water flux,higher salt resistance and better membrane performance than the HTI membrane.%以三乙酸纤维素(CTA)为膜材料,1,4-二氧六环、丙酮为溶剂,甲醇、乳酸为添加剂,采用相转换法制备了三乙酸纤维素正渗透膜。研究了不同1,4-二氧六环/丙酮配比、添加剂乳酸含量、挥发时间、膜厚度、热处理温度条件下正渗透膜性能的变化规律。研究表明,当采用纯水为原料液,0.56mol/L CaCl2为汲取液时,优化制备的CTA正渗透膜的水通量达到14.10L/(m2·h),溶质反扩散量为0.031mol/(m2·h);采用0.1mol/L NaCl为原料液,4mol/L葡萄糖为汲取液时,优化制备的CTA正渗透膜的水通量保持在5L/(m2·h)以上,对NaCl的截留率大于99%。CTA正渗透膜相比于HTI膜,具有较高的亲水性、水通量、截留率,稳定性更好。

  11. Study of preparation and gas separation property of ethyl cellulose/C60 composite membranes%乙基纤维素/C60复合膜制备及气体分离性能研究

    Institute of Scientific and Technical Information of China (English)

    马诚; 孔瑛; 杨金荣

    2012-01-01

    Ethyl cellulose/C60 composite membranes with different C60 content were prepared in this paper. The structure and gas permeation properties of the obtained membranes were investigated by UV-visible specmma,atomic force microscopy, X-ray diffraction and gas permeation tests. The results show that for the ethyl cellulose/Qo composite membranes with the C0content of 1. 6%,the permeation coefficients of CO2,H2 are 61. 29 Barrer and 78. 88 Barrer, respectively; the separation factors of H2/N2,CO2/N2 are 9.979 and 12. 84, respectively. Both gas permeation coefficient and separation factor of the above ethyl cellulose/C60composite membrane are higher than that of ethyl cellulose membrane. The effect of UV irradiation on the structure and gas permeation properties of the ethyl cellulose/C60 composite membranes was also studied. The results showed that the morphology of C60 on the surface of ethyl cellulose/C60 composite membranes changes from a discrete cluster structure to a continuous gentle hill-like structure during UV irradiation process. UV irradiation process has no noticeable effect on the d-spacing of ethyl cellulose molecular chain. The gas permeation properties of ethyl cellulose/C50 composite membranes, however,are significantly influenced by UV irradiation. By UV irradiation for ten minutes,the H2 and CO2 permeation coefficients of the ethyl cellulose/C60 composite membranes with C60 content of 1. 6% nearly reduces by 30%,and the separation factors of H2/N2 and CO2/N2 increase about 2 times.%为制备C60含量不同的乙基纤维素(EC)/C60复合膜,采用UV-可见光谱、AFM和XRD等手段对紫外光辐照前后复合膜结构进行表征,并考察其对气体分离及渗透性能的影响.结果表明,复合膜经紫外光辐照后,C60在膜表面的分布由独立的簇状结构转变为连续平缓的丘陵状结构,膜表面更加致密光滑;复合膜分子链间距未发生明显变化,但对N2、CO2、H2的渗透性能和H2/N2、CO2/N2分离

  12. 功能性再生纤维素复合膜的制备及性能研究进展%Research progress on preparation and properties of functional regenerated cellulose composite membranes

    Institute of Scientific and Technical Information of China (English)

    王晶晶; 王钱钱; 张超群; 孙建中

    2016-01-01

    纤维素是自然界中储量最大的天然高分子化合物,被认为是未来能源和化工的主要原料。然而,天然纤维素聚合度高、结晶度高的特性,使其难以溶于常规溶剂,极大限制了纤维素的应用。近年来,人们发现了多种新型纤维素溶剂体系,本文简要介绍了基于新型纤维素溶剂体系制备而来的再生纤维素膜以及一系列功能性再生纤维素基有机/无机复合膜材料。通过新型纤维素溶剂体系溶解再生得到的再生纤维素基复合膜在多孔性、热稳定性、强度等性能方面得到一定程度的改善,有望应用于包装、污水处理、传感器、生物医学等领域。本文基于再生纤维素膜及其复合膜材料的最新研究进展,对今后发展的热点方向进行了展望,旨在为纤维素溶解和功能性再生纤维素新材料的开发提供参考。%Cellulose, the most abundant natural renewable resources on the earth, has been considered as the main raw material for future energy and chemical industry. However, due to its high degree of polymerization and crystalline index, cellulose is extremely difficult to dissolve in conventional solvents, which greatly limits its application. More recently, many new cellulose solvents have been developed to overcome this problem. This paper briefly introduces a series of regenerated cellulose membranes and functional organic/inorganic regenerated cellulose composite membranes with these new cellulose solvents. It has been found that the properties of those cellulose composites, such as the porosity, thermal stability and mechanical properties are significantly improved, giving them promising applications in packaging, wastewater treatment, sensors, biological medicine, etc. The latest research progress of regenerated cellulose membranes and functional regenerated cellulose composites is summarized in this paper. Finally, the trends on developing cellulose solvents and

  13. Elemental composition of aerosol particulate matter collected on membrane filters: A comparison of results by PIXE and ICP-AES

    International Nuclear Information System (INIS)

    The elemental composition of aerosol matter (total suspended particles) collected on high-purity membrane filters during 24-h sampling periods with distinctly different pollution levels was analysed by proton-induced X-ray emission spectrometry (PIXE) and inductively coupled plasma atomic emission spectroscopy (ICP-AES). The mass density of the material deposited on 34-mm diameter filter areas ranged from 65 to 294 μg/cm2. Different spots on each sample as well as on blank reference filters were first analysed by PIXE (1.85 MeV protons, beam diameter 1.5 mm). Using a peak-fitting routine developed in-house together with an empirically determined sensitivity function, the background-corrected net spectra were converted to elemental yields. Absolute calibration was achieved by comparison against a thin-film copper standard prepared by evaporation. Following PIXE analysis, the whole filters with the aerosol deposits were digested by high-pressure ashing. A small amount of the dissolved material was analysed by ICP-AES using standard procedures. The mass fractions of elements in the particulate matter ranged from 6x10-5 for Co to 0.1 for Ca, with significant differences between the sampling periods. For some elements the mass fractions determined by PIXE showed a spot-to-spot variation by up to 30%. In most cases the mean elemental mass per filter determined by the two techniques agreed quite well, with a slight trend towards lower values by PIXE (10-15%). The difference is within the combined uncertainty of about 20%, estimated for elemental mass ratios determined by the two techniques. The Ti content determined by ICP-AES was always about 50% lower than by PIXE, the K content sometimes up to 30% higher. The discrepancy for Ti appears to reflect a digestion problem. The enhanced K content is attributed to a rather high instrumental background in ICP-AES

  14. Filtration efficiency and filter resistance of nylon-6 and nylon-6/chitosan nanofibrous membranes

    Directory of Open Access Journals (Sweden)

    Panu Danwanichakul

    2016-02-01

    Full Text Available Pore size reduction of nanofibrous membranes and the removal efficiencies for submicron PS particles (410, 200, 90 and 50 nm were investigated in this study. Blending chitosan with nylon-6 generated ultrafine fibers among typical nanofibers which could yield an electrospun membrane with smaller average pore size. It was found that high molecular weight chitosan could increase the filtration efficiency better than low molecular weight chitosan. The best membrane was obtained from solution of 30% wt/v nylon-6 and 0.06% wt/v chitosan. It had the average fiber size around 128 nm, average pore size around 110 nm and its thickness around 0.1 mm. While it could remove other larger particles completely, it gave the removal efficiency of 94% for 50-nm particles when it was used as a single-layer membrane and up to 97% as double-layer membranes with overall thickness of 0.17 mm. It was better than the commercial nylon membrane regarding its higher removal efficiency and smaller pore sizes so it has a potential to be used for sterilization of contaminated water.

  15. Silver nanoparticle/bacterial cellulose gel membranes for antibacterial wound dressing: investigation in vitro and in vivo

    International Nuclear Information System (INIS)

    Bacterial cellulose (BC) has attracted increasing attention as a novel wound dressing material, but its antimicrobial activity, which is one of the critical skin-barrier functions in wound healing, is not sufficient for use in practical applications. To overcome such a deficiency, silver nanoparticles were generated and self-assembled on the surface of BC nanofibers, forming a stable and evenly distributed Ag nanoparticle coated BC nanofiber (AgNP-BC). The performance of AgNP-BC was systematically studied in terms of antibacterial activities, cytocompatibility and effects on wound healing. The results showed that AgNP-BC exhibited significant antibacterial activity against Staphylococcus aureus. Moreover, AgNP-BC allowed attachment, and growth of rat fibroblasts with low cytotoxicity emerged. Based on these advantages, AgNP-BC samples were applied in a second-degree rat wound model. Wound flora showed a significant reduction during the healing. The fresh epidermal and dermis thicknesses with AgNP-BC samples were 111 and 855 µm respectively, higher than 74 and 619 µm for BC groups and 57 and 473 µm for untreated control wounds. The results demonstrated that AgNP-BC could reduce inflammation and promote scald wound healing. (paper)

  16. Metallization of bacterial cellulose for electrical and electronic device manufacture

    Energy Technology Data Exchange (ETDEWEB)

    Evans, Barbara R.; O' Neill, Hugh M.; Jansen, Valerie Malyvanh; Woodward, Jonathan

    2006-01-17

    The employment of metallized bacterial cellulose in the construction of fuel cells and other electronic devices is disclosed. The fuel cell includes an electrolyte membrane comprising a membrane support structure comprising bacterial cellulose, an anode disposed on one side of the electrolyte membrane, and a cathode disposed on an opposite side of the electrolyte membrane. At least one of the anode and the cathode comprises an electrode support structure comprising bacterial cellulose, and a catalyst disposed in or on the electrode support structure.

  17. Characterization of Cellulose Synthesis in Plant Cells

    Directory of Open Access Journals (Sweden)

    Samaneh Sadat Maleki

    2016-01-01

    Full Text Available Cellulose is the most significant structural component of plant cell wall. Cellulose, polysaccharide containing repeated unbranched β (1-4 D-glucose units, is synthesized at the plasma membrane by the cellulose synthase complex (CSC from bacteria to plants. The CSC is involved in biosynthesis of cellulose microfibrils containing 18 cellulose synthase (CesA proteins. Macrofibrils can be formed with side by side arrangement of microfibrils. In addition, beside CesA, various proteins like the KORRIGAN, sucrose synthase, cytoskeletal components, and COBRA-like proteins have been involved in cellulose biosynthesis. Understanding the mechanisms of cellulose biosynthesis is of great importance not only for improving wood production in economically important forest trees to mankind but also for plant development. This review article covers the current knowledge about the cellulose biosynthesis-related gene family.

  18. Characterization of Cellulose Synthesis in Plant Cells.

    Science.gov (United States)

    Maleki, Samaneh Sadat; Mohammadi, Kourosh; Ji, Kong-Shu

    2016-01-01

    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. PMID:27314060

  19. 离子液体法制备再生纤维素/角蛋白共混膜的研究%Research of Regenerated Cellulose/Keratin Blend Membranes Prepared from Ionic Liquids

    Institute of Scientific and Technical Information of China (English)

    张猛; 马博谋; 何春菊

    2013-01-01

    合成了离子液体1-丁基-3-甲基咪唑氯盐([BMIM]Cl),以其为溶剂溶解羊毛角蛋白和纤维素,并制得再生纤维素/角蛋白共混膜.通过扫描电子显微镜(SEM)、傅里叶红外光谱仪(FT-IR)、热失重分析仪(TGA)及强度测试仪等对共混膜的性能进行表征.测试结果表明:与单一原料组分相比,共混膜具有较高的热稳定性,但力学性能有所降低,此外,羊毛角蛋白再生前后的结构并未发生显著变化.%l-butyl-3-methylimidazolium chloride ([BMIM] CD was synthesized to dissolve wool keratin and cellulose, and the keratin/cellulose blend membranes were prepared. The properties of the membrane were evaluated through scanning electron microscope (SEM), Fourier transforms infrared (FT-IR), thermogravimetric analyzer (TGA) and tension strength tester. All the results showed that the blend membranes presented better thermal stability than that of raw cellulose and keratin, but inferior mechanical property. The structure of wool keratin didn't have remarkable change after regeneration.

  20. Regenerated cellulose membrane as bio-template for in-situ growth of visible-light driven C-modified mesoporous titania.

    Science.gov (United States)

    Mohamed, Mohamad Azuwa; W Salleh, W N; Jaafar, Juhana; Mohd Hir, Zul Adlan; Rosmi, Mohamad Saufi; Abd Mutalib, Muhazri; Ismail, Ahmad Fauzi; Tanemura, Masaki

    2016-08-01

    Visible light driven C-doped mesoporous TiO2 (C-MTiO2) nanorods have been successfully synthesized through green, low cost, and facile approach by sol-gel bio-templating method using regenerated cellulose membrane (RCM) as nanoreactor. In this study, RCM was also responsible to provide in-situ carbon sources for resultant C-MTiO2 nanorods in acidified sol at low temperatures. The composition, crystallinity, surface area, morphological structure, and optical properties of C-MTiO2 nanorods, respectively, had been characterized using FTIR, XRD, N2 adsorption/desorption, TEM, UV-vis-NIR, and XPS spectroscopy. The results suggested that the growth of C-MTiO2 nanorods was promoted by the strong interaction between the hydroxyl groups of RCMs and titanium ion. Optical and XPS analysis confirmed that carbon presence in TiO2 nanorods were responsible for band-gap narrowing, which improved the visible light absorption capability. Photocatalytic activity measurements exhibited the capability of C-MTiO2 nanorods in degradation of methyl orange in aqueous solution, with 96.6% degradation percentage under visible light irradiation. PMID:27112862

  1. Effect of Coagulation Bath and CastingSolution on Cellulose UF Membranes%凝固浴和铸膜液对新型纤维素超滤膜的影响

    Institute of Scientific and Technical Information of China (English)

    张耀鹏; 邵惠丽; 沈新元; 胡学超

    2000-01-01

    Cellulose and N - methylmorpholine - N - oxide (NMMO) system is selected to cast membrane with phase -inversion method. Several factors (concentration of casting solution, temperature and concentration of coagulation bath,different precipitation agents) on membrane performance are also studied.%以纤维素为原料,NMMO为溶剂,用相转化法制备超滤膜,并研究了凝固浴浓度、温度、有机醇作凝固剂及铸膜液浓度对膜性能的影响。

  2. A Hydrophobic Filter Confers the Cation Selectivity of Zygosaccharomyces rouxii Plasma-Membrane Na (+)/H (+) Antiporter

    Czech Academy of Sciences Publication Activity Database

    Kinclová-Zimmermannová, Olga; Falson, P.; Cmunt, Denis; Sychrová, Hana

    2015-01-01

    Roč. 427, č. 8 (2015), s. 1681-1697. ISSN 0022-2836 R&D Projects: GA ČR(CZ) GAP503/10/0307; GA MŠk(CZ) LD13037 Institutional support: RVO:67985823 Keywords : yeast * plasma membrane * sodium proton exchanger * substrate specificity * potassium transport Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 4.333, year: 2014

  3. A recommended procedure for the preparation of oriented clay-mineral specimens for X-ray diffraction analysis; modifications to Drever's filter-membrane peel technique

    Science.gov (United States)

    Pollastro, R.M.

    1982-01-01

    Extremely well-oriented clay mineral mounts for X-ray diffraction analysis can be prepared quickly and without introducing segregation using the filter-membrane peel technique. Mounting problems encountered with smectite-rich samples can be resolved by using minimal sample and partial air-drying of the clay film before transfer to a glass slide. Samples containing small quantities of clay can produce useful oriented specimens if Teflon masks having more restrictive areas are inserted above the membrane filter during clay deposition. War]page and thermal shock of glass slides can be controlled by using a flat, porous, ceramic plate as a holding surface during heat treatments.

  4. Evaluation of the Hydrophobic Grid Membrane Filter for the Enumeration of Moulds and Yeasts in Naturally-Contaminated Foods

    Directory of Open Access Journals (Sweden)

    V.H. Tournas

    2009-01-01

    Full Text Available Over 240 food samples from six food groups (tree nuts, grains and grain products, dried fruits, fresh produce, fruit juice, and dairy products were tested for levels of fungal contamination using the NEO-GRID hydrophobic grid membrane filter (HGMF and the FDA official (BAM method. Results showed that HGMF performed very well for all tested commodities giving yeast and mould (YM counts similar to those of the BAM (reference method. Statistical analysis of the data (t-test revealed no significant differences between the two methods for all foods tested. Regression analysis showed that there was a good fit linear relationship between the two methods for most of the commodities examined. Some difficulties were encountered during counting of the colonies on HGMF since the size of the grid is very small and the number of possible colonies per plate can reach 1600.

  5. Evaluation of the Hydrophobic Grid Membrane Filter for the Enumeration of Moulds and Yeasts in Naturally-Contaminated Foods

    Directory of Open Access Journals (Sweden)

    V.H. Tournas

    2009-07-01

    Full Text Available Over 240 food samples from six food groups (tree nuts, grains and grain products, dried fruits, fresh produce, fruit juice, and dairy products were tested for levels of fungal contamination using the NEO-GRID hydrophobic grid membrane filter (HGMF and the FDA official (BAM method. Results showed that HGMF performed very well for all tested commodities giving yeast and mould (YM counts similar to those of the BAM (reference method. Statistical analysis of the data (t-test revealed no significant differences between the two methods for all foods tested. Regression analysis showed that there was a good fit linear relationship between the two methods for most of the commodities examined. Some difficulties were encountered during counting of the colonies on HGMF since the size of the grid is very small and the number of possible colonies per plate can reach 1600.

  6. Enantiomeric separation of (R,S)-mandelic acid using cellulose acetate membrane%醋酸纤维素手性固膜对R,S-扁桃酸的拆分研究

    Institute of Scientific and Technical Information of China (English)

    徐晓林

    2014-01-01

    Since cellulose acetate has been widely used for membrane separations and chiral stationary phase in HPLC, It showed favorable film-forming performance and enantiomeric recognition potency. an enantioselective membrane was prepared using cellulose acetate as the membrane material. The flux and permselective properties of a membrane were studied using mandelic acid racemate as the feed solution. The top surface and cross-section morphology of the resulting membrane were examined using scanning electron microscopy. An optical resolution of at 3.9 enantiomeric separation factor was achieved when the enantioselective membrane was prepared with 30wt.%cellulose acetate, 15wt.%N, N-dimethylformamide in the casting solution of acetone, the evaporation time of 5 minutes and operating pressure of 0.2 MPa. This work indicates that the enantioselective cellulose acetate membrane could soon become very attractive for industrial uses.%醋酸纤维素已经被广泛用于膜分离技术及用作高效液相色谱手性固定相,显示了它具有优良的成膜性能和手性识别能力。因此以醋酸纤维素为膜材料,制备醋酸纤维素手性固膜,使用R,S-扁桃酸作为原料液检测膜的通量及其手性拆分能力,并使用扫描电子显微镜对膜表面及截面的形态结构进行了表征。研究显示:当CA浓度为30%,DMF浓度为15%,铸膜液挥发5min,操作压力为0.2 MPa,样品浓度为0.5 mg/mL时,膜具有良好的拆分效果,R,S-扁桃酸对映体的分离因子可以达到3.9,说明膜分离技术是进行大规模手性拆分非常有潜力的方法之一,具有良好的工业应用前景。

  7. Inferring Trial-to-Trial Excitatory and Inhibitory Synaptic Inputs from Membrane Potential using Gaussian Mixture Kalman Filtering

    Directory of Open Access Journals (Sweden)

    Milad eLankarany

    2013-09-01

    Full Text Available Time-varying excitatory and inhibitory synaptic inputs govern activity of neurons and process information in the brain. The importance of trial-to-trial fluctuations of synaptic inputs has recently been investigated in neuroscience. Such fluctuations are ignored in the most conventional techniques because they are removed when trials are averaged during linear regression techniques. Here, we propose a novel recursive algorithm based on Gaussian mixture Kalman filtering for estimating time-varying excitatory and inhibitory synaptic inputs from single trials of noisy membrane potential in current clamp recordings. The Kalman filtering is followed by an expectation maximization algorithm to infer the statistical parameters (time-varying mean and variance of the synaptic inputs in a non-parametric manner. As our proposed algorithm is repeated recursively, the inferred parameters of the mixtures are used to initiate the next iteration. Unlike other recent algorithms, our algorithm does not assume an a priori distribution from which the synaptic inputs are generated. Instead, the algorithm recursively estimates such a distribution by fitting a Gaussian mixture model. The performance of the proposed algorithms is compared to a previously proposed PF-based algorithm (Paninski et al., 2012 with several illustrative examples, assuming that the distribution of synaptic input is unknown. If noise is small, the performance of our algorithms is similar to that of the previous one. However, if noise is large, they can significantly outperform the previous proposal. These promising results suggest that our algorithm is a robust and efficient technique for estimating time varying excitatory and inhibitory synaptic conductances from single trials of membrane potential recordings.

  8. Dissolution and regeneration membrane of cellulose in ionic liquid%两种离子液体中制备再生棉浆纤维素膜及其性能研究

    Institute of Scientific and Technical Information of China (English)

    刘洋; 王兆梅; 肖凯军

    2013-01-01

    Cotton pulp was dissolved in ionic liquids [Bmim]CI and [Emim]Ac and regenerated membrane was successfully prepared. Its dissolution process was observed by polarizing microscope. The structural differences between cotton pulp and regenerated cellulose membrane were investigated using Fourier transform infrared (FT-IR) spectroscopy.X-ray diffraction and thermogravimetry(TG) measurements. The results showed that cotton pulp was directly dissolved by ionic liquids and its crystalline form transformed from cellulose Ⅰ to cellulose Ⅱ . The regenerated cellulose membranes obtained showed a dense and smooth structure and displayed a slight thermal stability loss. The tensile strength could be up to 94.55MPa and 39.15MPa from [Bmim]CI and [Emim]Ac. respectively.%以1-丁基-3-甲基咪唑氯盐([Bmim]Cl)和1-乙基-3-甲基咪唑醋酸盐([Emim]Ac)两种离子液体作为棉浆粕的溶解体系,并制备了再生棉浆粕纤维素膜,采用红外光谱、X射线衍射、热重分析、扫描电镜和质构仪对棉浆再生前后纤维素膜进行结构表征 结果表明,将棉浆直接溶解在离子液体中,再生后纤维素晶型由Ⅰ型向Ⅱ型的晶型转变,热稳定性略有下降 再生纤维素膜结构致密均匀,力学性能优异,在[Bmim]Cl和[Emim]Ac中拉伸强度分别可达94.55MPa和39.15MPa.

  9. 纤维素/海藻酸钠共混膜的制备及力学性能%Preparation and mechanical properties of cellulose/sodium alginate blend membranes

    Institute of Scientific and Technical Information of China (English)

    李娜; 刘文洁; 罗虎

    2013-01-01

    Cellulose and sodium alginate were separately dissolved in the blend system of sodium hydroxide,urea and thiourea to prepare cellulose and cellulose/sodium alginate blend membranes.The optimal process conditions of cellulose membrane were decided by orthogonal experiment and single factor experiment.The preparation technology of cellulose/sodium alginate blend membrane was also studied.The results showed that the membrane prepared from 4.5% cellulose solution by mass fraction had the optimal tensile strength of 5.2 MPa while coagulating in 5% sulfuric acid solution at 25 ℃ for 15 min and plasticizing in 20% glycerin solution for 30 min; and the obtained cellulose/sodium alginate blend membrane had the optimal tensile strength of 3.50 MPa when the process conditions were optimized as followed:the blend solution containing 4.5% cellulose and 3% sodium alginate by mass fraction at the mass ratio of 100/5,soaking in 5% sulfuric acid solution and reacting for 15 min,coagulating in 10% calcium chloride solution for 10 min,and plasticizing in 15% glycerin solution for 15 min.%将纤维素和海藻酸钠分别溶于氢氧化钠/尿素/硫脲体系,制得纤维素膜和纤维素/海藻酸钠共混膜,通过正交实验和单因素实验法分析,确定制备纤维素膜的最佳工艺条件,在此基础上研究了纤维素/海藻酸钠共混膜的制备工艺.结果表明:质量分数为4.5%的纤维素溶液所制得的膜在25℃的5%的硫酸溶液中凝固15 min,20%的甘油溶液中塑化30 min,其膜的拉伸强度较佳为5.2 MPa;纤维素/海藻酸钠共混膜的较佳工艺:质量分数分别为4.5%的纤维素溶液和3%的海藻酸钠溶液按质量比100/5共混后先浸入5%硫酸溶液中反应15 min,再放入10%氯化钙溶液中凝固10 min,用15%甘油溶液塑化15 min后,共混膜的拉伸强度达到3.50 MPa.

  10. Irradiation of large area Mylar membrane and characterization of nuclear track filter

    Indian Academy of Sciences (India)

    N K Acharya; P K Yadav; S Wate; Y K Vijay; F Singh; D K Avasthi

    2004-10-01

    Ion irradiation of Si8+ ion beam of 100 MeV was scattered by a gold foil on a Mylar membrane of 25 m thickness in the form of film roll (width, 12.5 cm and length, 400 cm) at the Nuclear Science Centre, New Delhi. The characterization of etched nuclear tracks was carried out by gas permeation measurements. The samples cut from the film roll of required size for permeability measurements were etched in a controlled manner in a constant temperature bath of 6N NaOH solution. The opening of the conical etched tracks was characterized by hydrogen gas permeation.

  11. Cellulose nanomaterials in water treatment technologies.

    Science.gov (United States)

    Carpenter, Alexis Wells; de Lannoy, Charles-François; Wiesner, Mark R

    2015-05-01

    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, 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. PMID:25837659

  12. Cellulose biosynthesis and function in bacteria.

    OpenAIRE

    Ross, P; Mayer, R; Benziman, M

    1991-01-01

    The current model of cellulose biogenesis in plants, as well as bacteria, holds that the membranous cellulose synthase complex polymerizes glucose moieties from UDP-Glc into beta-1,4-glucan chains which give rise to rigid crystalline fibrils upon extrusion at the outer surface of the cell. The distinct arrangement and degree of association of the polymerizing enzyme units presumably govern extracellular chain assembly in addition to the pattern and width of cellulose fibril deposition. Most e...

  13. Cellulose is not just cellulose

    DEFF Research Database (Denmark)

    Hidayat, Budi Juliman; Felby, Claus; Johansen, Katja S.;

    2012-01-01

    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...... 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...

  14. Membrane-Filtered Olive Mill Wastewater: Quality Assessment of the Dried Phenolic-Rich Fraction.

    Science.gov (United States)

    Sedej, Ivana; Milczarek, Rebecca; Wang, Selina C; Sheng, Runqi; de Jesús Avena-Bustillos, Roberto; Dao, Lan; Takeoka, Gary

    2016-04-01

    A current trend in olive mill wastewater (OMWW) management is to not only decrease environmental pollution but also to extract and utilize valuable by-products. Therefore, the objectives of this study were to explore different techniques for drying a phenolic-rich membrane filtration fraction of OMWW and compare the techniques in terms of the dried product quality and feasibility of the process. The OMWW from 2 (3-phase and 2-phase) California mills was subjected to a 2-step membrane filtration process using a novel vibratory system. The reverse osmosis retentate (RO-R) is a phenolic-rich coproduct stream, and the reverse osmosis permeate is a near-pure water stream that could be recycled into the milling process. Spray-, freeze-, and infrared-drying were applied to obtain solid material from the RO-R. Drying of the RO-R was made possible only with addition of 10% maltodextrin as a carrier. The total soluble phenolics in dried RO-R were in the range 0.15 to 0.58 mg gallic acid equivalents/g of dry weight for 2-phase RO-R, and 1.38 to 2.17 mg gallic acid equivalents/g of dry weight for the 3-phase RO-R. Spray-dried RO-R from 3-phase OMWW showed remarkable antioxidant activity. Protocatechuic acid, tyrosol, vanillic acid, and p-coumaric acid were quantified in all dried RO-R, whereas 3-hydroxytyrosol was found in 3-phase dried RO-R. This combination of separation and drying technologies helps to add value and shelf-stability to an olive oil by-product and increase environmental sustainability of its production. PMID:26989993

  15. Development of a colony lift immunoassay to facilitate rapid detection and quantification of Escherichia coli O157:H7 from agar plates and filter monitor membranes.

    Science.gov (United States)

    Ingram, D T; Lamichhane, C M; Rollins, D M; Carr, L E; Mallinson, E T; Joseph, S W

    1998-07-01

    E. coli O157:H7 is a food-borne adulterant that can cause hemorrhagic ulcerative colitis and hemolytic uremic syndrome. Faced with an increasing risk of foods contaminated with E. coli O157:H7, food safety officials are seeking improved methods to detect and isolate E. coli O157:H7 in hazard analysis and critical control point systems in meat- and poultry-processing plants. A colony lift immunoassay was developed to facilitate the positive identification and quantification of E. coli O157:H7 by incorporating a simple colony lift enzyme-linked immunosorbent assay with filter monitors and traditional culture methods. Polyvinylidene difluoride (PVDF) membranes (Millipore, Bedford, Mass.) were prewet with methanol and were used to make replicates of every bacterial colony on agar plates or filter monitor membranes that were then reincubated for 15 to 18 h at 36 +/- 1 degree C, during which the colonies not only remained viable but were reestablished. The membranes were dried, blocked with blocking buffer (Kirkegaard and Perry Laboratories [KPL], Gaithersburg, Md.), and exposed for 7 min to an affinity-purified horseradish peroxidase-labeled goat anti-E. coli O157 antibody (KPL). The membranes were washed, exposed to a 3,3',5,5'-tetramethylbenzidine membrane substrate (TMB; KPL) or aminoethyl carbazole (AEC; Sigma Chemical Co., St. Louis, Mo.), rinsed in deionized water, and air dried. Colonies of E. coli O157:H7 were identified by either a blue (via TMB) or a red (via AEC) color reaction. The colored spots on the PVDF lift membrane were then matched to their respective parent colonies on the agar plates or filter monitor membranes. The colony lift immunoassay was tested with a wide range of genera in the family Enterobacteriaceae as well as different serotypes within the E. coli genus. The colony lift immunoassay provided a simple, rapid, and accurate method for confirming the presence of E. coli O157:H7 colonies isolated on filter monitors or spread plates by

  16. Performance of hydrate cellulose membrane for zinc-silver battery after remodeling%锌银电池用水化纤维素膜改性后的性能

    Institute of Scientific and Technical Information of China (English)

    张红平; 郑艳丽; 赵力群

    2011-01-01

    讨论了在不同组成的反应液中,反应温度和时间对锌银电池用水化纤维素膜进行改性的影响.对面积电阻、耐电解液的腐蚀能力、吸碱率及保液能力等测试以及实验电池电性能分析,总结了水化纤维素膜的性能.当甲醛浓度为30%,温度为20℃、反应时间为10 min时,改性后水化纤维素膜的各项物理性能比改性前提高近5%,制备的8 Ah XYZ8型锌银电池的循环寿命增加9次,放电容量、放电电压分别提高约20%和8%.%The remolding of hydrate cellulose membrane for zino-silver battery in the solution with different composition, temperature and reaction time was discussed. The performance of hydrate cellulose membrane was summarized by the tests of area resistance, electrolyte corrosion resistance ability, alkali uptake and liquid preserving ability, the electrical performance analysis of experimental battery. When the formaldehyde content was 30% , the temperature was 20 ℃, the reaction time was 10 min, the physical properties of hydrate cellulose membrane after remolding increased nearly 5% than before remolding, the life of prepared 8 Ah XYZ8 zinc-silver battery increased 9 cycles, the discharge capacity and discharge voltage increased about 20% and 8%, respectively.

  17. Membraner

    DEFF Research Database (Denmark)

    Bach, Finn

    2009-01-01

    Notatet giver en kort introduktion til den statiske virkemåde af membraner og membrankonstruktioner......Notatet giver en kort introduktion til den statiske virkemåde af membraner og membrankonstruktioner...

  18. Adsorption of papain with Cibacron Blue F3GA carrying cellulose affinity membranes%木瓜蛋白酶在染料Cibacron Blue F3GA纤维素亲和膜上的吸附研究

    Institute of Scientific and Technical Information of China (English)

    张海涛; 聂华丽; 陈天翔; 苏赛男; 朱利民

    2009-01-01

    以纤维素滤纸膜为载体,染料Cibacron Blue F3GA为配基,制备了一种新型亲和膜色谱介质.采用扫描电镜、红外光谱、元素分析等方法对亲和膜介质进行鉴定与表征,该膜具有良好的色谱性能.亲和膜对F3GA的键合质量摩尔浓度达93.7 μmol/g.研究了木瓜蛋白酶在亲和膜上的吸附行为,实验表明:在30℃下、酶质量浓度为2 mg/mL、pH=8.0时,吸附质量比可达57.9 mg/g,改变pH值及离子强度等条件对吸附质量比有明显的影响.在最适条件下吸附遵循Langmuir型吸附.可以初步推断,纤维素滤纸膜可以制成性能优良的亲和膜色谱介质,成本低廉,适合工业化分离纯化生物大分子.%Cibacron Blue F3GA (CB F3GA) as a hgand was immobilized onto cellulose membranes to produce a novel affinity membrane. The physical properties and its apphcations of affinity membrane chromatography were examined by means of scanning electron microscope (SEM), infra-red spectrum and elementary analysis, etc. The bonding content of CB F3GA attached on membranes was 93.7 μmol/g. The adsorption behavior of papain on affinity membranes was studied. The result shows that higher papain adsorption capacity (up to 57.9 mg/g membrane) can be achieved under the condition of 2.0 mg/mL papain solution, 30℃, pH=8.0. Changing pH and ionic strength has obvious effects on the adsorption of papain. The adsorption of papain on affinity membranes can be described by the Langmuir isotherm. Therefore, it can prehminarily foresee that the cellulose membrane can become the low-cost but high-efficiency affinity membranes base for papain separation, which is applicable for commercial separating the biological macromolecular.

  19. Outline of Preparation and Fire- retardant Properties Detection of Nanocrystalline Cellulose Fire- retardant Membranes%纳米纤维素阻燃膜的制备及阻燃性检测概述

    Institute of Scientific and Technical Information of China (English)

    徐睿; 王海英; 孙睿; 雷舒

    2012-01-01

    Methods of fire -retardant properties evaluation, fire -retardant cellulose fibers preparation, and nano- crystalline cellulose preparation were introduced, respectively. The national standards of fire - retardant properties evalua- tion for fire - retardant protective clothing and forest fire - proof clothing were compared. National standards GB/T5454 - 1997, textiles - burning properties test oxygen index method, was used in forest fire - proof clothing. Preparation method and application prospects of nanocrystalline cellulose fire - retardant membranes were explored.%分别介绍了阻燃性能指标评价、阻燃纤维素纤维的制备、纳米纤维素的制备等方法,比较了阻燃防护服和森林防火服的阻燃性能指标评价国家标准,森林防火服的阻燃性能指标评价还另外采用了GB/T5454—1997纺织品燃烧性能试验氧指数法国家标准,探讨了纳米纤维素复合阻燃膜的制备方法及其应用前景。

  20. 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.

  1. Two-day hydrophobic grid membrane filter method for yeast and mold enumeration in foods using YM-11 agar: collaborative study.

    Science.gov (United States)

    Entis, P

    1996-01-01

    Twenty laboratories participated in a collaborative study to validate a 2-day hydrophobic grid membrane filter method using YM-11 agar for enumeration of yeast and mold in foods. Six naturally contaminated food products were included in the study: garlic powder, raw ground beef, walnuts, flour/meal, orange juice, and yogurt. The test method produced significantly higher results than the 5-day pour plate reference method for orange juice and significantly lower, though numerically similar, results for walnuts and yogurt. Differences between the test and reference methods were not significant for garlic powder, raw ground beef, or flour/meal. Repeatability and reproducibility were similar for both the test and reference methods in all cases. The hydrophobic grid membrane filter method for enumeration of yeast and mold in foods has been adopted by AOAC INTERNATIONAL. PMID:8823916

  2. Electrochemical Properties of LLTO/Fluoropolymer-Shell Cellulose-Core Fibrous Membrane for Separator of High Performance Lithium-Ion Battery

    OpenAIRE

    Fenglin Huang; Wenting Liu; Peiying Li; Jinxia Ning; Qufu Wei

    2016-01-01

    A superfine Li0.33La0.557TiO3 (LLTO, 69.4 nm) was successfully synthesized by a facile solvent-thermal method to enhance the electrochemical properties of the lithium-ion battery separator. Co-axial nanofiber of cellulose and Poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) was prepared by a co-axial electrospinning technique, in which the shell material was PVDF-HFP and the core was cellulose. LLTO superfine nanoparticles were incorporated into the shell of the PVDF-HFP. The core–...

  3. Early observation of bacterial cellulose membrane for repair of dural defects in rabbits%细菌纤维素膜修复兔硬脑膜缺损的早期观察

    Institute of Scientific and Technical Information of China (English)

    徐晨; 陈世文; 田恒力; 王敢; 郭衍; 袁陆涛

    2013-01-01

    目的 应用细菌纤维素膜修补兔硬脑膜缺损,观察植入后早期局部组织学改变以及炎症因子表达情况.方法 24只新西兰兔随机分为A、B两组,每组12只.所有动物经切除双侧硬脑膜制备2 cm×1 cm的缺损.A组动物的右侧硬脑膜缺损采用细菌纤维素膜修补,左侧硬脑膜缺损则不予修补,于术后第30、90、180天采集标本,行组织学检查.B组动物的右侧硬脑膜缺损采用细菌纤维素膜修补,左侧硬脑膜缺损以人工硬膜修补,于术后第7、14、21天采集修补部位组织,采用RT-PCR技术检测促炎症细胞因子白介素1β(IL-1β)、白介素6(IL-6)和肿瘤坏死因子α(TNF-α) mRNA的表达.结果 所有实验动物均存活,切口无感染.在A组的细菌纤维素膜修补侧,细菌纤维素膜均匀覆盖脑表面,与脑组织无粘连;外侧面纤维结缔组织增生,内侧面成纤维细胞排列均匀,新生血管形成,炎症反应轻微;在A组的未修补侧,大脑与皮下组织直接粘连.RT-PCR检测结果显示:术后各时间点,B组细菌纤维素膜修补侧IL-1 β和IL-6 mRNA表达水平均显著低于人工硬膜修补侧,两侧TNF-α mRNA表达水平相近.结论 采用细菌纤维素膜修复硬脑膜缺损,不易与脑组织形成粘连且早期炎症反应轻微.细菌纤维素膜可能成为理想的硬脑膜替代材料.%Objective To patch up the dural defects of rabbits with bacteria cellulose membrane, and observe the early pathological change and inflammatory response after implantation. Methods Twenty-four New Zealand rabbits were randomly divided into group A and group B, with 12 rabbits in each group. The bilateral dura matter of rabbits were removed, and defects of 2 cm x 1 cm were prepared. In group A, the right dural defects were repaired with bacteria cellulose membrane, no repair was made on the left dural defects, and samples were taken 30 d, 90 d and 180 d after operation for pathological examinations. In group B, the

  4. Cellulose biosynthesis in Acetobacter xylinum

    International Nuclear Information System (INIS)

    Time-lapse video microscopy has shown periodic reversals during the synthesis of cellulose. In the presence of Congo Red, Acetobacter produces a band of fine fibrils. The direction of cell movement is perpendicular to the longitudinal axis of cell, and the rate of movement was decreased. A linear row of particles, presumably the cellulose synthesizing complexes, was found on the outer membrane by freeze-fracture technique. During the cell cycle, the increase of particles in linear row, the differentiation to four linear rows and the separation of the linear rows have been observed. A digitonin-solubilized cellulose synthase was prepared from A. xylinum, and incubated under conditions known to lead to active in vitro synthesis of 1,4-β-D-glucan polymer. Electron microscopy revealed that clusters of fibrils were assembled within minutes. Individual fibrils are 17 ± 2 angstroms in diameter. Evidence for the cellulosic composition of newly synthesized fibrils was based on incorporation of tritium from UDP-[3H] glucose binding of gold-labeled cellobiohydrolase, and an electron diffraction pattern identified as cellulose II polymorph instead of cellulose I

  5. Screening of the effective cellulose-degradable strain and its application in the production of cellulose bioethanol

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Strains from the cellulose-containing environment were collected. Primary screening(by filter-paper Hutchison solid culture medium and sodium carboxymethylcellulose solid culture medium) and reelection(by filter-paper inorganic salt culture medium and sodium carboxymethylcellulose Congo red culture medium) indicated that five strains obtained were best suited for high performance cellulose degradation. Determination of sodium carboxymethylcellulose activity(CMCA) and filter paper activity(FPA) was accomplis...

  6. Proteomic profiling of cellulase-aid-extracted membrane proteins for functional identification of cellulose synthase complexes and their potential associated- components in cotton fibers.

    Science.gov (United States)

    Li, Ao; Wang, Ruyi; Li, Xianliang; Liu, Mingyong; Fan, Jian; Guo, Kai; Luo, Bing; Chen, Tingting; Feng, Shengqiu; Wang, Yanting; Wang, Bingrui; Peng, Liangcai; Xia, Tao

    2016-01-01

    Cotton fibers are an excellent model for understanding of cellulose biosynthesis in higher plants. In this study, we determined a high cellulose biosynthesis activity in vitro by optimizing biochemical reaction conditions in cotton fibers. By adding a commercial cellulase enzyme into fibers extraction process, we extracted markedly higher levels of GhCESA1 and GhCESA8 proteins and observed an increase in β-1,4-glucan and β-1,3-glucan products in vitro. LC-MS/MS analysis of anti-GhCESA8-immunoprecipitated proteins showed that 19 proteins could be found in three independent experiments including four CESAs (GhCESA1,2,7,8), five well-known non-CESA proteins, one callose synthase (CALS) and nine novel proteins. Notably, upon the cellulase treatment, four CESAs, one CALS and four novel proteins were measured at relatively higher levels by calculating total peptide counts and distinct peptide numbers, indicating that the cellulase-aid-extracted proteins most likely contribute to the increase in β-glucan products in vitro. These results suggest that the cellulase treatment may aid to release active cellulose synthases complexes from growing glucan chains and make them more amenable to extraction. To our knowledge, it is the first time report about the functional identification of the potential proteins that were associated with plant cellulose and callose synthases complexes by using the cellulase-aided protein extraction. PMID:27192945

  7. 纤维素-丝素复合膜的制备与表征%Preparation and characterization of cellulose/silk composite membrane

    Institute of Scientific and Technical Information of China (English)

    李娟; 何建新; 余燕平

    2011-01-01

    The cellulose-silk fibroin composite film is prepared by mixing cellulose solution dissolved primary wood pulp in solution containing of NaOH/urea/thiourea/water and silk fibroin solution. The composite film is characterized by scanning electron microscope (SEM) , Fourier transform infrared spectrometer (FT-IR) , X-ray diffraction (XRD). SEM shows the surface of the composite is uniform and rough. The as-prepared composite film may be a potential biomedical material. The results of IR and XRD show that composite film is composed of cellulose and silk fibroin molecules and exists an interaction including hydrogen bond between the molecular of cellulose and silk fibroin.%通过NaOH/尿素/硫脲/水新型溶剂溶解原生木浆纤维素得到纤维素溶液,并与丝素溶液混合制备纤维素-丝素复合膜.利用扫描电镜、红外光谱、X-射线衍射对复合材料的结构进行表征.SEM结果表明复合材料表面粗糙,比表面积较大,可以作为潜在的生物医用材料.IR和X-衍射结果表明再生纤维素与丝素分子之间存在着强烈的氢键作用,且二者相容性较好.

  8. Drug absorption in vitro model: filter-immobilized artificial membranes. 2. Studies of the permeability properties of lactones in Piper methysticum Forst.

    Science.gov (United States)

    Avdeef, A; Strafford, M; Block, E; Balogh, M P; Chambliss, W; Khan, I

    2001-12-01

    The assessment of transport properties of 23 drug and natural product molecules was made using the in vitro model based on filter-immobilized artificial membranes (filter-IAM), assembled from phosphatidylcholine in dodecane, in buffer solutions at pH 7.4. Five of the compounds were lactones extracted from the roots of the kava-kava plant. Experiments were designed to test the effects of stirring (0-600 rpm) during assays and the effects of varying the assay times (2-15 h). The highly mobile kava lactones permeated in the order dihydromethisticin (40)>yangonin (37)>kavain (34)>methisticin (32)>desmethoxyyangonin (26), the numbers in parentheses being the measured effective permeabilities in units of 10(-6) cm/s. By comparison, commercial drugs ranked: phenazopyridine (35)>testosterone (19)>propranolol (13)>ketoconazole (6.3)>piroxicam (2.2)>caffeine (1.7)>metoprolol (0.8)>terbutaline (0.01). In addition to permeability measurements, membrane retention of compounds was determined. Yangonin, desmethoxyyangonin, ketoconazole, and phenazopyridine were more than 60% retained by the artificial membranes containing phospholipids. Stirring during assay significantly increased the observed permeabilities for highly mobile molecules, but had minimal impact on the poorly permeable molecules. The influence of hydrogen bonding was explored by determining permeabilities using filters coated with dodecane free of phospholipids. In the filter-IAM method, concentrations were determined by microtitre plate UV spectrophotometry and by LC-MS. Higher-throughput was achieved with direct UV by the use of 96-well microtitre plate formats and with LC-MS by the use of cassette dosing (five-in-one). PMID:11684401

  9. In-situ biogas sparging enhances the performance of an anaerobic membrane bioreactor (AnMBR) with mesh filter in low-strength wastewater treatment.

    Science.gov (United States)

    Li, Na; Hu, Yi; Lu, Yong-Ze; Zeng, Raymond J; Sheng, Guo-Ping

    2016-07-01

    In the recent years, anaerobic membrane bioreactor (AnMBR) technology is being considered as a very attractive alternative for wastewater treatment due to the striking advantages such as upgraded effluent quality. However, fouling control is still a problem for the application of AnMBR. This study investigated the performance of an AnMBR using mesh filter as support material to treat low-strength wastewater via in-situ biogas sparging. It was found that mesh AnMBR exhibited high and stable chemical oxygen demand (COD) removal efficiencies with values of 95 ± 5 % and an average methane yield of 0.24 L CH4/g CODremoved. Variation of transmembrane pressure (TMP) during operation indicated that mesh fouling was mitigated by in-situ biogas sparging and the fouling rate was comparable to that of aerobic membrane bioreactor with mesh filter reported in previous researches. The fouling layer formed on the mesh exhibited non-uniform structure; the porosity became larger from bottom layer to top layer. Biogas sparging could not change the composition but make thinner thickness of cake layer, which might be benefit for reducing membrane fouling rate. It was also found that ultrasonic cleaning of fouled mesh was able to remove most foulants on the surface or pores. This study demonstrated that in-situ biogas sparging enhanced the performance of AnMBRs with mesh filter in low-strength wastewater treatment. Apparently, AnMBRs with mesh filter can be used as a promising and sustainable technology for wastewater treatment. PMID:27003270

  10. Tentative identification of the choline transporter in cholinergic presynaptic plasma membrane preparations from Torpedo electric organ

    International Nuclear Information System (INIS)

    This paper demonstrates specific high-affinity choline transport into resealed membrane fragments from Torpedo. The amount of bound choline to various subfractions of synaptosome lysate is estimated, and tentative identification of the choline transporter was made. After synaptosomes from Torpedo were pepred the diluted ample was immediately mixed and applied to a 0.45 um cellulose filter and the membranes were washed. The filters were removed, solubilized in Bray's solution and assayed for radioactivity in a Berthold LB 5004 liquid scintillation spectrometer. Acetylcholinesterase was measred and Quabain-sensitive (Na+ -K+) ATPase activity was assayed. Tritium-choline chloride and tritium=acetylcoA were used in the experiments

  11. Membrane materials for storing biological samples intended for comparative nanotoxicological testing

    Science.gov (United States)

    Metelkin, A.; Kuznetsov, D.; Kolesnikov, E.; Chuprunov, K.; Kondakov, S.; Osipov, A.; Samsonova, J.

    2015-11-01

    The study is aimed at identifying the samples of most promising membrane materials for storing dry specimens of biological fluids (Dried Blood Spots, DBS technology). Existing sampling systems using cellulose fiber filter paper have a number of drawbacks such as uneven distribution of the sample spot, dependence of the spot spreading area on the individual biosample properties, incomplete washing-off of the sample due to partially inconvertible sorption of blood components on cellulose fibers, etc. Samples of membrane materials based on cellulose, polymers and glass fiber with applied biosamples were studied using methods of scanning electron microscopy, FT-IR spectroscopy and surface-wetting measurement. It was discovered that cellulose-based membrane materials sorb components of biological fluids inside their structure, while membranes based on glass fiber display almost no interaction with the samples and biological fluid components dry to films in the membrane pores between the structural fibers. This characteristic, together with the fact that membrane materials based on glass fiber possess sufficient strength, high wetting properties and good storage capacity, attests them as promising material for dry samples of biological fluids storage systems.

  12. Photochemical modification of poly(ether sulfone) ultrafiltration membranes by UV-assisted graft polymerization for the prevention of biofouling

    Science.gov (United States)

    Pieracci, John Paul

    Membranes are widely used by the biotechnology industry in the separation and recovery of proteins from biological solutions. Fouling of membrane surfaces by irreversible protein adsorption during ultrafiltration causes loss of membrane permeability and can reduce membrane selectivity and lead to significant product loss through denaturation. In this work, low fouling poly(ether sulfone) (PES) ultrafiltration membranes were produced by ultraviolet (UV) assisted graft polymerization of hydrophilic vinyl monomers using a newly developed photochemical dip modification technique. This technique was developed to make the UV modification process more easily adaptable to continuous membrane manufacturing processes. A method was also developed to measure and track the degree of polymer grafting on the membrane surface using attenuated total reflection Fourier transform infrared spectroscopy (FTIR/ATR). Grafting the hydrophilic monomer N-vinyl-2-pyrrolidinone (NVP) onto the membrane surface increased surface wettability and produced membranes with the high wettability of regenerated cellulose membranes. The enhanced surface wettability significantly decreased irreversible adsorptive fouling during the filtration of the protein bovine serum albumin (BSA). In order to maintain the rejection of BSA after modification, PES chain scission was tightly controlled by regulating the UV wavelength range and the light intensity used. The UV reactor system was operated with 300 nm UV lamps and a benzene filter used to remove high energy wavelengths below 275 nm that were determined to cause severe loss of BSA rejection due to pore enlargement from extensive chain scission. Dip modification caused membrane permeability to decrease due to the grafted chains blocking the membrane pores. The use of a chain transfer agent during modification followed by ethanol cleaning increased modified membrane permeability, but BSA rejection was severely decreased. The resultant membranes produced by

  13. Kinetic study of photo-grafting and photo-cross-linking of a cis-poly butadiene onto cellulose from asymmetric membranes

    International Nuclear Information System (INIS)

    Photochemical grafting onto cellulose and successive photo cross-linking of 2,00-12,00 mg.cm-2 of a cys-poly butadiene, containing 80% cis groups, were investigated kinetically at 30 0 C in the presence of 1,2-diphenyl-2,2-dimethoxy ethanone as a photo initiator to polymer varied between 0,070 and 1,115. Irradiations were carried out poly chromatically, in air or under a stream of nitrogen, with incident radiation of flux I of 2,1.10-8 einstein.s-1.cm-2. In light of this information, the mechanism of photo-grafting and photo-cross linking of cis-poly-butadiene on cellulose surface is discussed. (author)

  14. Screening of the effective cellulose-degradable strain and its application in the production of cellulose bioethanol

    Institute of Scientific and Technical Information of China (English)

    Peng-fei Gao; Dai-di Fan; Pei Ma; Yan-e Luo; Xiao-xuan Ma; Chen-hui Zhu; Jun-feng Hui

    2009-01-01

    Strains from the cellulose-containing environment were collected. Primary screening(by filter-paper Hutchison solid culture medium and sodium carboxymethylcellulose solid culture medium) and reelection(by filter-paper inorganic salt culture medium and sodium carboxymethylcellulosc Congo red coltnre medium) indicated that five strains obtained were best suited for high performance cellulose degradation. Determination of sodium carboxymethylcellulose activity(CMCA) and filter paper activity(FPA) was accomplished for each of the five. The strongest of the five in CMCA and FPA was applied to the production of cellulose bioethanol by separate hydrolysis and fermentation(SHF) and simultaneous saccharification and fermentation(SSF) respectively.

  15. Evaluation of the bubble point test of a 0.22-μm membrane filter used for the sterilizing filtration of PET radiopharmaceuticals

    International Nuclear Information System (INIS)

    We developed a bubble point test kit and investigated the bubble point test of a 0.22-μm membrane filter used for the sterilizing filtration of [18F]FDG, [11C]MET and [11C]PIB. The bubble point test of the Millex-GS vented filter was often difficult due to air leakage from the vented portion of this filter. Therefore, to close the vented portion of this filter simply and reliably, we investigated the use of various materials. The bubble point test of the Millex-GS vented filter was performed by closing the vented portion of this filter with various materials, such as vinyl tape, plastic paraffin film (parafilm), urethane elastomer adhesive mat and polyethylene foam cushion tape. Gradually, the plunger inside a syringe filled with air was pushed down to increase the pressure on the pressure gauge and the bubble point test kit. Simultaneously, the pressure when a continuous stream of air bubbles that appeared out of the 0.22-μm membrane filter was measured as the product-wetted bubble point value. Then, the plunger inside a syringe filled with 10 mL of water was pushed down to wash the 0.22-μm membrane filter. As in the case in the above-mentioned method of measuring the product-wetted bubble point, the water-wetted bubble point value was measured. The use of the polyethylene foam cushion tape and a double clip could easily and reliably prevent air leakage from the vented portion of the Millex-GS vented filter. In the bubble point test of [18F]FDG, [11C]MET and [11C]PIB, the product-wetted bubble point values were 382.7 ± 6.9 kPa, 385.4 ± 6.2 kPa and 351.6 ± 7.6 kPa, respectively. The bubble point ratio was used to determine the minimum product-wetted bubble point value. All results of the product-wetted bubble point test were beyond the minimum product-wetted bubble point value (334.4 kPa ([18F]FDG), 334.4 kPa ([11C]MET) and 310.3 kPa ([11C]PIB)). Then, the water-wetted bubble point values were 396.5 ± 8.3 kPa, 395.8 ± 8.3 kPa and 390.3 ± 7.6 k

  16. Method of forming an electrically conductive cellulose composite

    Science.gov (United States)

    Evans, Barbara R.; O'Neill, Hugh M.; Woodward, Jonathan

    2011-11-22

    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.

  17. The influence of hydrolysis induced biopolymers from recycled aerobic sludge on specific methanogenic activity and sludge filterability in an anaerobic membrane bioreactor.

    Science.gov (United States)

    Buntner, D; Spanjers, H; van Lier, J B

    2014-03-15

    The objective of the present study was to evaluate the impact of excess aerobic sludge on the specific methanogenic activity (SMA), in order to establish the maximum allowable aerobic sludge loading. In batch tests, different ratios of aerobic sludge to anaerobic inoculum were used, i.e. 0.03, 0.05, 0.10 and 0.15, showing that low ratios led to an increased SMA. However, the ratio 0.15 caused more than 20% SMA decrease. In addition to the SMA tests, the potential influence of biopolymers and extracellular substances, that are generated as a result of excess aerobic sludge hydrolysis, on membrane performance was determined by assessing the fouling potential of the liquid broth, taking into account parameters such as specific resistance to filtration (SRF) and supernatant filterability (SF). Addition of aerobic sludge to the anaerobic biomass resulted in a high membrane fouling potential. The increase in biopolymers could be ascribed to aerobic sludge hydrolysis. A clear positive correlation between the concentration of the colloidal fraction of biopolymer clusters (cBPC) and the SRF was observed and a negative correlation between the cBPC and the SF measured at the end of the above described SMA tests. The latter implies that sludge filtration resistance increases when more aerobic sludge is hydrolyzed, and thus more cBPC is released. During AnMBR operation, proteins significantly contributed to sludge filterability decrease expressed as SRF and SF, whereas the carbohydrate fraction of SMP was of less importance due to low concentrations. On the contrary, carbohydrates seemed to improve filterability and diminish SRF of the sludge. Albeit, cBPC increase caused an increase in mean TMP during the AnMBR operation, confirming that cBPC is positively correlated to membrane fouling. PMID:24284260

  18. A quantitative study of air-borne particulate matter collected on membrane filters by means of X-ray photoelectron spectroscopy

    International Nuclear Information System (INIS)

    The capability of X-ray photoelectron spectroscopy, XPS or ESCA, in analysing oxidation states and measuring the concentration of elements present in air pollution particulates collected on membrane filters is evaluated. Semi-quantitative data are compared with those from XRF and wet chemical analysis. Differences of about a factor of 2.0-2.5 are found which are critically discussed in relation to particle size and the distribution of ionic species. The importance of intrinsic properties of matrix materials and instrumental factors is also discussed. (orig.)

  19. Quantitation of platelet loss with indium-111 labeled platelets in a hollow-fiber membrane oxygenator and arterial filter during extracorporeal circulation in a pig model

    International Nuclear Information System (INIS)

    Platelet consumption in a hollow-fiber membrane oxygenator (HFMO) and arterial filter (AF) during cardiopulmonary bypass (CPB) was quantified in five pigs using Indium-111 labeled autologous platelets. Platelet labeling was performed 20-24 hours before CPB. After general endotracheal anesthesia, the pigs were systemically heparinized and were placed on CPB via a median sternotomy. After 3 hours of CPB, radioactivity was quantified with a gamma camera and an ionization chamber. The percent of injected dose (mean ± SD) was 0.79 +/- 0.45 in the HFMO, 2.52 ± 0.93 in AF, 4.3 ± 1.2 in blood loss during CPB. Platelet consumption in HFMO during CPB was lower than in bubble oxygenators (19%) or silicone membrane oxygenators (12%) as observed in previous studies

  20. 聚乙烯醇/纳米纤维素复合膜的渗透汽化性能及结构表征%Pervaporation Properties and Characterization of Poly( vinyl alcohol ) /Cellulose Nanocrystal Composite Membranes

    Institute of Scientific and Technical Information of China (English)

    白露; 张力平; 曲萍; 高源; 秦竹; 孙素琴

    2011-01-01

    将聚乙烯醇/纳米纤维素(PVA/NCC)复合膜应用于乙醇-水混合溶液的渗透汽化脱水过程,探讨了纳米纤维素对膜的溶胀性能、机械性能和渗透汽化性能的影响; 利用原子力显微镜(AFM)探测了纳米纤维素的形貌特征; 采用傅里叶变换红外光谱仪(FTIR)、扫描电镜(SEM)、差示扫描量热仪(DSC)和热重分析仪(TGA)对膜结构和热性能进行了表征.研究结果表明,棒状的纳米纤维素与PVA基体间形成了强烈的氢键作用且均匀分散在PVA基质中; 纳米纤维素的加入提高了膜的熔融温度,增加了膜的热稳定性,有效地抑制了膜的溶胀,并提高了膜的机械性能; 在PVA中添加纳米纤维素可以提高膜的渗透汽化分离性能,用纳米纤维素含量为2%的复合膜在80 ℃时分离体积分数为90%的乙醇水溶液,膜的分离因子达到347,比未加入纳米纤维素时提高24%; 而渗透通量为288 g/(m2·h),比未加入纳米纤维素时下降11%.%Poly ( vinyl alcohol ) ( PVA )/cellulose nanocrystal ( NCC ) composite membranes were used in the pervaporation separation of water-ethanol feed mixtures, and characterized by Fourier transform infrared spectroscopy( lTIR), scanning electron microscopy( SEM), differential scanning calorimetric(DSC) and thermogravimetry(TG). Atomic force microscope (AFM) was used to characterize the cellulose nanocrystal. The characterization results demonstrated that NCC displayed slender rods and dispersed homogeneously within the PVA matrix, which could be assigned to the hydrogen bonds formed between PVA and NCC. The DSC and TG analysis demonstrated that the nanocomposite membranes exhibited an increase in melting temperature and higher thermal resistance. With the addition of NCC, the mechanical properties of the nanocomposite membranes were improved. Moreover, the nanocomposite membranes had good pervaporation properties. Among all the prepared membranes, PVA/NCC nanocomposite membrane containing 2

  1. Cellulose based conductive polymers

    OpenAIRE

    Lin, Haishu

    2015-01-01

    Conductive fibers show potential applications in different areas. In this thesis, cellulose and its derivatives, including carboxymethyl cellulose, cellulose acetate as well as methyl cellulose were used to produce fibers via wet spinning. Different conductive materials were also introduced in an attempt to obtain cellulose-derived conductive fibers. Different conductive fillers (Zelec, carbon black, conductive polymers) were evaluated. Among them, PEDOT and PPy conductive polymers showed...

  2. Experimental Evolution of Trichoderma citrinoviride for Faster Deconstruction of Cellulose

    OpenAIRE

    Lin, Hui; Travisano, Michael; Kazlauskas, Romas J.

    2016-01-01

    Engineering faster cellulose deconstruction is difficult because it is a complex, cooperative, multi-enzyme process. Here we use experimental evolution to select for populations of Trichoderma citrinoviride that deconstruct up to five-fold more cellulose. Ten replicate populations of T. citrinoviride were selected for growth on filter paper by serial culture. After 125 periods of growth and transfer to fresh media, the filter paper deconstruction increased an average of 2.5 fold. Two populati...

  3. Characterization of cellulose extracted from oil palm empty fruit bunch

    Science.gov (United States)

    Sisak, Muhammad Asri Abdul; Daik, Rusli; Ramli, Suria

    2015-09-01

    Recently, cellulose has been studied by many researchers due to its promising properties such as biodegradability, biocompatibility, hydrophilicity and robustness. Due to that it is applied in many fields such as paper, film, drug delivery, membranes, etc. Cellulose can be extracted from various plants while oil palm empty fruit bunch (OPEFB) is the one of its sources. In this study, cellulose was extracted by chemical treatments which involved the use of formic acid and hydrogen peroxide to remove hemicellulose and lignin components. Maximum yield was 43.22%. Based on the FT-IR spectra, the peak of wax (1735 cm-1), hemicellulose (1375 cm-1) and lignin (1248 cm-1 and 1037 cm-1) were not observed in extracted cellulose. TGA analysis showed that the extracted cellulose starts to thermally degrade at 340 °C. The SEM analysis suggested that the cellulose extracted from OPEFB was not much different from commercial cellulose.

  4. The performance of a biological aerated filter loaded with a novel non-sintered fly-ash ceramsite as pretreatment for dual membrane processes.

    Science.gov (United States)

    Li, Lihua; Hu, Chaowu; Dai, Xiulan; Jin, Wenjie; Hu, Cheng; Ma, Fang

    2015-01-01

    This work focused on wastewater reclamation of secondary treated ethylene chemical plant effluent, which contained high conductivity and high organic concentration. To reduce the cost and improve operation stability, a biological aerated filter-ultrafiltration-reverse osmosis (BAF-UF-RO) process was proposed. The feasibility and effectiveness of BAF loaded with a novel non-sintered fly-ash ceramsite (NSFC) as a pretreatment method of a dual membrane system were investigated in detail. The results showed that the CODCr, turbidity, NH3-N and the silt density index (SDI) in the effluent from the BAF were reduced to 24.2 mg/L, 12.17 NTU, 0.42 mg/L and 7.52, respectively, and most of the organic compounds were biodegraded. The BAF-UF-RO process was stable with a recovery rate of 75%, and the desalination rate was up to about 97.5%. Compared with the UF-RO process, the operating pressure and backwash frequency decreased from 1.12-1.26 Mpa and 3 times/d to 0.94-0.98 Mpa and 2 times/d, respectively. After continuous operation for four months, there appeared to be no need for chemical cleaning of the RO membrane. Moreover, the analysis results of X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy proved that there was only slight membrane fouling, which was mainly colloidal blocking caused by refractory organic compound. PMID:25686627

  5. Enhanced power production of a membrane electrode assembly microbial fuel cell (MFC) using a cost effective poly [2,5-benzimidazole] (ABPBI) impregnated non-woven fabric filter.

    Science.gov (United States)

    Choi, Soojung; Kim, Jung Rae; Cha, Jaehwan; Kim, Yejin; Premier, Giuliano C; Kim, Changwon

    2013-01-01

    A membrane electrode assembly (MEA) microbial fuel cell (MFC) with a non-woven paper fabric filter (NWF) was investigated as an alternative to a proton exchange membrane (PEM) separator. The MFC with a NWF generated a cell voltage of 545 mV and a maximum power density of 1027 mW/m(3), which was comparable to that obtained from MFCs with a PEM (551 mV, 609 mW/m(3)). The MFC with a NWF showed stable cell performance (550 mV) over 300 days, whereas, the MFC with PEM performance decreased significantly from 551 mV to 415 mV due to biofilm formation and chemical precipitation on the membrane surface. Poly [2,5-benzimidazole] (ABPBI) was evaluated with respect to its capacity to increased proton conductivity and contact between separator and electrodes. The overall performance of the MFC with ABPBI was improved by enhancing the ion conductivity and steric contact, producing 766 mW/m(3) at optimum loading of 50 mg ABPBI/cm(2). PMID:23196216

  6. Non-traditional solutions of cellulose and it's derivatives and their processing products

    OpenAIRE

    Grinshpan, D. D.; Savitskaya, T. A.; Tsygankova, N. G.

    2003-01-01

    The main achievements of the Laboratory of cellulose solutions and their processing products in the field of the elaboration of new cellulose dissolving processes, the homogeneous synthesis of cellulose derivatives, the elaboration of the incompatible polymer solutions stabilization, the creation of new film - fabric materials and filtering equipments on their base, the preparation of hard quickly disintegrated drug forms (tablets, granules) using new water soluble cellulose derivative have b...

  7. Inferring trial-to-trial excitatory and inhibitory synaptic inputs from membrane potential using Gaussian mixture Kalman filtering

    OpenAIRE

    Milad Lankarany

    2013-01-01

    Time-varying excitatory and inhibitory synaptic inputs govern activity of neurons and process information in the brain. The importance of trial-to-trial fluctuations of synaptic inputs has recently been investigated in neuroscience. Such fluctuations are ignored in the most conventional techniques because they are removed when trials are averaged during linear regression techniques. Here, we propose a novel recursive algorithm based on Gaussian mixture Kalman filtering (GMKF) for estimating t...

  8. Cyclic voltammetry of ion transfer across a room temperature ionic liquid membrane supported by a microporous filter

    Czech Academy of Sciences Publication Activity Database

    Langmaier, Jan; Samec, Zdeněk

    2007-01-01

    Roč. 9, č. 9 (2007), s. 2633-2638. ISSN 1388-2481 R&D Projects: GA AV ČR IAA400400704 Institutional research plan: CEZ:AV0Z40400503 Keywords : room-temperature ionic membrane * cyclic voltammetry * standard Gibbs energy of ion transfer * linear Gibbs energy relationship Subject RIV: CG - Electrochemistry Impact factor: 4.186, year: 2007

  9. Construction of nerve guide conduits from cellulose/soy protein composite membranes combined with Schwann cells and pyrroloquinoline quinone for the repair of peripheral nerve defect

    International Nuclear Information System (INIS)

    Regeneration and functional reconstruction of peripheral nerve defects remained a significant clinical challenge. Nerve guide conduits, with seed cells or neurotrophic factors (NTFs), had been widely used to improve the repair and regeneration of injured peripheral nerve. Pyrroloquinoline quinone (PQQ) was an antioxidant that can stimulate nerve growth factors (NGFs) synthesis and accelerate the Schwann cells (SCs) proliferation and growth. In present study, three kinds of nerve guide conduits were constructed: one from cellulose/SPI hollow tube (CSC), another from CSC combined with SCs (CSSC), and the third one from CSSC combined with PQQ (CSSPC), respectively. And then they were applied to bridge and repair the sciatic nerve defect in rats, using autograft as control. Effects of different nerve guide conduits on the nerve regeneration were comparatively evaluated by general analysis, sciatic function index (SFI) and histological analysis (HE and TEM). Newly-formed regenerative nerve fibers were observed and running through the transparent nerve guide conduits 12 weeks after surgery. SFI results indicated that the reconstruction of motor function in CSSPC group was better than that in CSSC and CSC groups. HE images from the cross-sections and longitudinal-sections of the harvested regenerative nerve indicated that regenerative nerve fibers had been formed and accompanied with new blood vessels and matrix materials in the conduits. TEM images also showed that lots of fresh myelinated and non-myelinated nerve fibers had been formed. Parts of vacuolar, swollen and abnormal axons occurred in CSC and CSSC groups, while the vacuolization and swell of axons was the least serious in CSSPC group. These results indicated that CSSPC group had the most ability to repair and reconstruct the nerve structure and functions due to the comprehensive contributions from hollow CSC tube, SCs and PQQ. As a result, the CSSPC may have the potential for the applications as nerve guide

  10. Construction of nerve guide conduits from cellulose/soy protein composite membranes combined with Schwann cells and pyrroloquinoline quinone for the repair of peripheral nerve defect

    Energy Technology Data Exchange (ETDEWEB)

    Luo, Lihua [Department of Biomedical Engineering, School of Basic Medical Sciences, Wuhan University, Wuhan 430071 (China); Center of Molecular Medicine, School of Medicine, Hubei University of Arts and Sciences, Xiangyang 441053 (China); Gan, Li; Liu, Yongming; Tian, Weiqun; Tong, Zan [Department of Biomedical Engineering, School of Basic Medical Sciences, Wuhan University, Wuhan 430071 (China); Wang, Xiong; Huselstein, Celine [Ingénierie Moléculaire et Physiopathologie Articulaire (IMoPA), UMR 7365 CNRS – Université de Lorraine, Biopôle, 54500 Vandoeuvre-lès-Nancy (France); Chen, Yun, E-mail: yunchen@whu.edu.cn [Department of Biomedical Engineering, School of Basic Medical Sciences, Wuhan University, Wuhan 430071 (China)

    2015-02-20

    Regeneration and functional reconstruction of peripheral nerve defects remained a significant clinical challenge. Nerve guide conduits, with seed cells or neurotrophic factors (NTFs), had been widely used to improve the repair and regeneration of injured peripheral nerve. Pyrroloquinoline quinone (PQQ) was an antioxidant that can stimulate nerve growth factors (NGFs) synthesis and accelerate the Schwann cells (SCs) proliferation and growth. In present study, three kinds of nerve guide conduits were constructed: one from cellulose/SPI hollow tube (CSC), another from CSC combined with SCs (CSSC), and the third one from CSSC combined with PQQ (CSSPC), respectively. And then they were applied to bridge and repair the sciatic nerve defect in rats, using autograft as control. Effects of different nerve guide conduits on the nerve regeneration were comparatively evaluated by general analysis, sciatic function index (SFI) and histological analysis (HE and TEM). Newly-formed regenerative nerve fibers were observed and running through the transparent nerve guide conduits 12 weeks after surgery. SFI results indicated that the reconstruction of motor function in CSSPC group was better than that in CSSC and CSC groups. HE images from the cross-sections and longitudinal-sections of the harvested regenerative nerve indicated that regenerative nerve fibers had been formed and accompanied with new blood vessels and matrix materials in the conduits. TEM images also showed that lots of fresh myelinated and non-myelinated nerve fibers had been formed. Parts of vacuolar, swollen and abnormal axons occurred in CSC and CSSC groups, while the vacuolization and swell of axons was the least serious in CSSPC group. These results indicated that CSSPC group had the most ability to repair and reconstruct the nerve structure and functions due to the comprehensive contributions from hollow CSC tube, SCs and PQQ. As a result, the CSSPC may have the potential for the applications as nerve guide

  11. Simulations of Cellulose Translocation in the Bacterial Cellulose Synthase Suggest a Regulatory Mechanism for the Dimeric Structure of Cellulose

    Energy Technology Data Exchange (ETDEWEB)

    Knott, Brandon C.; Crowley, Michael F.; Himmel, Michael E.; Zimmer, Jochen; Beckham, Gregg T.

    2016-05-01

    The processive cycle of the bacterial cellulose synthase (Bcs) includes the addition of a single glucose moiety to the end of a growing cellulose chain followed by the translocation of the nascent chain across the plasma membrane. The mechanism of this translocation and its precise location within the processive cycle are not well understood. In particular, the molecular details of how a polymer (cellulose) whose basic structural unit is a dimer (cellobiose) can be constructed by adding one monomer (glucose) at a time are yet to be elucidated. Here, we have utilized molecular dynamics simulations and free energy calculations to the shed light on these questions. We find that translocation forward by one glucose unit is quite favorable energetically, giving a free energy stabilization of greater than 10 kcal mol-1. In addition, there is only a small barrier to translocation, implying that translocation is not rate limiting within the Bcs processive cycle (given experimental rates for cellulose synthesis in vitro). Perhaps most significantly, our results also indicate that steric constraints at the transmembrane tunnel entrance regulate the dimeric structure of cellulose. Namely, when a glucose molecule is added to the cellulose chain in the same orientation as the acceptor glucose, the terminal glucose freely rotates upon forward motion, thus suggesting a regulatory mechanism for the dimeric structure of cellulose. We characterize both the conserved and non-conserved enzyme-polysaccharide interactions that drive translocation, and find that 20 of the 25 residues that strongly interact with the translocating cellulose chain in the simulations are well conserved, mostly with polar or aromatic side chains. Our results also allow for a dynamical analysis of the role of the so-called 'finger helix' in cellulose translocation that has been observed structurally. Taken together, these findings aid in the elucidation of the translocation steps of the Bcs

  12. Experimental lamellar keratoplasty in rabbits using microfibrilar cellulose membrane: clinical, morphological and immunohistochemical findings Ceratoplastia lamelar experimental em coelhos usando membrana microfibrilar de celulose: achados clínicos, morfológicos e imunoistoquímicos

    Directory of Open Access Journals (Sweden)

    Luciana Riacciardi Macedo

    2010-02-01

    Full Text Available The clinical, histopathological and immunohistochemical features of the cornea were investigated in adult male New Zealand rabbits submitted to lamellar keratoplasty with microfibrillar cellulose membrane. Thirty animals were divided into five groups (n=6 and evaluated up to 60 days after surgery. Clinical examination revealed moderate manifestations of edema, blepharospasm and photophobia on the second day, which became mild or disappeared after the seventh day. This period was characterized clinically by repair of the corneal defect. Histopathological analysis showed the presence of a thin layer of squamous cells covering the damaged area as early as 7th day, accompanied by a mild infiltrate of polymorphonuclear cells. Blood vessels were observed in the epithelium after the 15th day, which had regressed by day 48. Ki67 antibody labeling showed an increase of proliferating cells in the epithelium by the 15th day and in the stroma by day 30. Remodeling and epithelial adhesion were observed during this period. Microfibrillar cellulose membrane (Bionext® used for lamellar keratoplasty was found to yield good results considering the good integration of the implant.Avaliaram-se aspectos clínicos, histopatógicos e imunoistoquímicos da córnes de coelhos da raça Nova Zelândia adultos e machos em ceratoplastias lamelares com membrana de celulose microfibrilar. Trinta animais distribuídos em cinco grupos (n=6 foram estudados por até 60 dias de pós-operatório. A avaliação clínica revelou manifestações moderadas de edema, blefaroespasmo e fotofobia ao segundo dia, evoluindo para formas discretas ou ausentes a partir do sétimo dia, período em que se observou, clinicamente, reparo do defeito corneal. A histopatologia revelou uma fina camada de células escamosas, recobrindo a área lesada já aos sete dias, com discreto infiltrado de células polimorfonucleares. Observaram-se vasos no epitélio a partir do 15o dia, com regressão ao 48o dia

  13. Investigation of Bacterial Cellulose Biosynthesis Mechanism in Gluconoacetobacter hansenii

    OpenAIRE

    Mohite, Bhavna V.; Patil, Satish V

    2014-01-01

    The present study explores the mechanism of cellulose biosynthesis in Gluconoacetobacter hansenii. The cellulose synthase enzyme was purified as membrane fraction and solubilized by treatment with 0.1% digitonin. The enzyme was separated by native-gel electrophoresis and β -D-glucan analysis was carried out using in vitro gel assay. The cellulose synthase has glycoprotein nature and composed two polypeptide subunits of 93 KDa and 85 KDa. The confirmation of β -1,4-glucan (cellulose) was perfo...

  14. The determination of the pore distribution and the consideration of methods leading to the prediction of retention characteristics of membrane filters

    International Nuclear Information System (INIS)

    Presented here is a method for the determination of the pore size distribution of a membrane microfilter. Existing test metods are either cumbersome, as is the Erbe method; time consuming, as is the evaluation of electron microscope photographs; do not really measure the pore distribution, as the mercury intrusion method; or do not satisfactorily evaluate the large pore range of the filter, as is the case with the automated ASTM method. The new method described in this paper is based upon the solution of the integral flow equation for the pore distribution function. A computer program evaluates the flow test data and calculates the numerical pore distribution, water-flow distribution, air-flow distribution and capillary area distribution, as a function of the pore size. (orig./RW)

  15. Decomposition of cellulose by ultrasonic welding in water

    Science.gov (United States)

    Nomura, Shinfuku; Miyagawa, Seiya; Mukasa, Shinobu; Toyota, Hiromichi

    2016-07-01

    The use of ultrasonic welding in water to decompose cellulose placed in water was examined experimentally. Filter paper was used as the decomposition material with a horn-type transducer 19.5 kHz adopted as the ultrasonic welding power source. The frictional heat at the point where the surface of the tip of the ultrasonic horn contacts the filter paper decomposes the cellulose in the filter paper into 5-hydroxymethylfurfural (5-HMF), furfural, and oligosaccharide through hydrolysis and thermolysis that occurs in the welding process.

  16. Evaluation of Several Procedures for Immobilizing Cholesterol Oxidase Based on Cellulose Acetate Membrane

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Immobilized cholesterol oxidase (COD) membrane with higher catalytic activity is important for biosensor. In this paper, several procedures for immobilizing COD based on cellulose acetate (CA) membrane are studied. Reasons causing different catalytic activities are also discussed.

  17. Effects of membrane-filtered soy hull pectin and pre-emulsified fiber/oil on chemical and technological properties of low fat and low salt meat emulsions.

    Science.gov (United States)

    Kim, Hyun-Wook; Lee, Yong Jae; Kim, Yuan H Brad

    2016-06-01

    The objectives of this study were to determine efficacy of a membrane filtration in soy hull pectin purification and evaluate combined effects of soy hull pectin and pre-emulsified fiber/oil (PE) on chemical composition and technological properties of low fat and low salt meat emulsions. Soy hull pectin was purified through two different methods (alcohol-washed (ASP) and membrane-filtered (MSP)). Insoluble soy hull residues after pectin extraction were incorporated with sunflower oil and water for the PE preparation. Meat emulsion was formulated with 58 % pork, 20 % ice, 20 % pork backfat, and 2 % NaCl as control. A total of six low fat and low salt meat emulsions (1 % NaCl and 10 % backfat) was manufactured with 1 % pectin (with/without ASP or MSP) and 10 % PE (with/without). The pectin content of ASP and MSP was 0.84 and 0.64 g L-galacturonic acid/g dry sample, respectively. The inclusion of soy hull pectin caused similar results on chemical composition, color, cooking loss, and texture of the meat emulsions, regardless of the purification method. In addition, positive impacts of the combined treatments with soy hull pectin and PE compared to single treatments on cooking loss and texture of the meat emulsions were observed. Results suggest that membrane filtration could be an effective alternative method to purify pectin, instead of alcohol-washing, and both soluble pectin and insoluble fiber from soy hulls could be used as a functional non-meat ingredient to manufacture various low fat and low salt meat products. PMID:27478213

  18. Development of a novel pH sensor based upon Janus Green B immobilized on triacetyl cellulose membrane: Experimental design and optimization

    Science.gov (United States)

    Chamkouri, Narges; Niazi, Ali; Zare-Shahabadi, Vali

    2016-03-01

    A novel pH optical sensor was prepared by immobilizing an azo dye called Janus Green B on the triacetylcellulose membrane. Condition of the dye solution used in the immobilization step, including concentration of the dye, pH, and duration were considered and optimized using the Box-Behnken design. The proposed sensor showed good behavior and precision (RSD < 5%) in the pH range of 2.0-10.0. Advantages of this optical sensor include on-line applicability, no leakage, long-term stability (more than 6 months), fast response time (less than 1 min), high selectivity and sensitivity as well as good reversibility and reproducibility.

  19. PROPERTIES OF BACTERIAL CELLULOSE AND ITS INFLUENCE ON THE PHYSICAL PROPERTIES OF PAPER

    OpenAIRE

    Wen-Hua Gao; Ke-Fu Chen; Ren-Dang Yang; Fei Yang; Wen-Jia Han

    2011-01-01

    Bacterial cellulose is a promising source of biodegradable polymers having high purity. The time required to disperse bacterial cellulose wet membranes was studied, along with evaluation by infrared spectroscopy and thermal analysis of the dispersed bacterial fiber and tests of the physical properties of the sheet. The results showed that bacterial cellulose wet membrane can be dispersed well, forming fibers when the dispersing time was 3 minutes at a suitable concentration. FT-IR results sho...

  20. Cellulose-Microtubule Uncoupling Proteins Prevent Lateral Displacement of Microtubules during Cellulose Synthesis in Arabidopsis.

    Science.gov (United States)

    Liu, Zengyu; Schneider, Rene; Kesten, Christopher; Zhang, Yi; Somssich, Marc; Zhang, Youjun; Fernie, Alisdair R; Persson, Staffan

    2016-08-01

    Cellulose is the most abundant biopolymer on Earth and is the major contributor to plant morphogenesis. Cellulose is synthesized by plasma membrane-localized cellulose synthase complexes (CSCs). Nascent cellulose microfibrils become entangled in the cell wall, and further catalysis therefore drives the CSC forward through the membrane: a process guided by cortical microtubules via the protein CSI1/POM2. Still, it is unclear how the microtubules can withstand the forces generated by the motile CSCs to effectively direct CSC movement. Here, we identified a family of microtubule-associated proteins, the cellulose synthase-microtubule uncouplings (CMUs), that located as static puncta along cortical microtubules. Functional disruption of the CMUs caused lateral microtubule displacement and compromised microtubule-based guidance of CSC movement. CSCs that traversed the microtubules interacted with the microtubules via CSI1/POM2, which prompted the lateral microtubule displacement. Hence, we have revealed how microtubules can withstand the propulsion of the CSCs during cellulose biosynthesis and thus sustain anisotropic plant cell growth. PMID:27477947

  1. Preparation of lipid nanoemulsions by premix membrane emulsification with disposable materials.

    Science.gov (United States)

    Gehrmann, Sandra; Bunjes, Heike

    2016-09-25

    The possibility to prepare nanoemulsions as drug carrier systems on small scale was investigated with disposable materials. For this purpose premix membrane emulsification (premix ME) as a preparation method for nanoemulsions with narrow particle size distributions on small scale was used. The basic principle of premix ME is that the droplets of a coarse pre-emulsion get disrupted by the extrusion through a porous membrane. In order to implement the common preparation setup for premix ME with disposable materials, the suitability of different syringe filters (made from polyethersulfone, cellulose acetate, cellulose ester and nylon) and different pharmaceutically relevant emulsifiers (phospholipids, polysorbate 80 and sucrose laurate) for the preparation of nanoemulsions was investigated. Already the preparation of the premix could be realized by emulsification with the help of two disposable syringes. As shown for a phospholipid-stabilized emulsion, the polyethersulfone filter was the most appropriate one and was used for the study with different emulsifiers. With this syringe filter, the median particle size of all investigated emulsions was below 500nm after 21 extrusion cycles through a 200nm filter and a subsequent extrusion cycle through a 100nm filter. Furthermore, the particle size distribution of the polysorbate 80- and sucrose laurate-stabilized emulsions prepared this way was very narrow (span value of 0.7). PMID:27477104

  2. Endotoxin removal by end-line filters.

    OpenAIRE

    Vanhaecke, E; De Muynck, C; Remon, J P; Colardyn, F

    1989-01-01

    Four commonly used end-line filters, one with a charge-modified hydrophilic nylon filter (ELD96; Pall Biomedical Ltd., Portsmouth, United Kingdom), one with an unmodified nylon filter (FAE020; Pall Biomedical), and two with hydrophilic cellulose ester filters (Ivex-HP, Millipore Corp., Bedford, Mass.; Sterifix, Braun-Gelman, Brussels, Belgium), were evaluated for their endotoxin-removing capacity in saline and 5% glucose. Natural endotoxins derived from Escherichia coli 8739 and the lipopolys...

  3. Tests on the sampling performance of 3 kinds of filters for α-radioactive aerosol sampling

    International Nuclear Information System (INIS)

    Filter for α-radioactive aerosol sampling is one of the important parts in radioactive aerosol detection. Filter with high efficiency, low self-absorption and high-performed surface collection will improve the speed of monitoring and energy resolution of α. In this study, 3 different types of filters were chosen for sampling of natural radon daughter aerosol. The parameters of collection efficiency, self-absorption, surface collection characteristics and flow rate under the same resistance were measured. In the same condition of the aerosol concentration, sampling flow rate and sampling time, the membrane filter which is made of mixed cellulose ester with the mean pore radius of 0.8 μm, has the highest filter efficiency and less self-absorption; heavy-ion microporous membrane with pore radius of 0.4μm has minimal self-absorption and superior surface collection, which is important in improving the α energy resolution; the glass fiber filter has the lowest resistance, suiting for large flow rate in sampling. (authors)

  4. CELLULOSIC NANOCOMPOSITES: A REVIEW

    Directory of Open Access Journals (Sweden)

    Martin A. Hubbe

    2008-08-01

    Full Text Available Because of their wide abundance, their renewable and environmentally benign nature, and their outstanding mechanical properties, a great deal of attention has been paid recently to cellulosic nanofibrillar structures as components in nanocomposites. A first major challenge has been to find efficient ways to liberate cellulosic fibrils from different source materials, including wood, agricultural residues, or bacterial cellulose. A second major challenge has involved the lack of compatibility of cellulosic surfaces with a variety of plastic materials. The water-swellable nature of cellulose, especially in its non-crystalline regions, also can be a concern in various composite materials. This review of recent work shows that considerable progress has been achieved in addressing these issues and that there is potential to use cellulosic nano-components in a wide range of high-tech applications.

  5. Cellulose-silica aerogels.

    Science.gov (United States)

    Demilecamps, Arnaud; Beauger, Christian; Hildenbrand, Claudia; Rigacci, Arnaud; Budtova, Tatiana

    2015-05-20

    Aerogels based on interpenetrated cellulose-silica networks were prepared and characterised. Wet coagulated cellulose was impregnated with silica phase, polyethoxydisiloxane, using two methods: (i) molecular diffusion and (ii) forced flow induced by pressure difference. The latter allowed an enormous decrease in the impregnation times, by almost three orders of magnitude, for a sample with the same geometry. In both cases, nanostructured silica gel was in situ formed inside cellulose matrix. Nitrogen adsorption analysis revealed an almost threefold increase in pores specific surface area, from cellulose aerogel alone to organic-inorganic composite. Morphology, thermal conductivity and mechanical properties under uniaxial compression were investigated. Thermal conductivity of composite aerogels was lower than that of cellulose aerogel due to the formation of superinsulating mesoporous silica inside cellulose pores. Furthermore, composite aerogels were stiffer than each of reference aerogels. PMID:25817671

  6. The Application Improvement of Membrane Filter Press in the Post Treatment of Titanium Dioxide Production%隔膜压滤机在钛白粉后处理生产中应用的改进

    Institute of Scientific and Technical Information of China (English)

    王佳林; 刘建良; 李建军; 江书安

    2012-01-01

    The technology improvement of filter pressing and scrubbing system in the post treatment of chlorination TiO, pigment production is expatiated in this paper, which adopts a kind of new type membrane filter press and a kind of new filtering and scrubbing method to filtering, scrubbing and dewatering of TiO2 slurry, and the final formed filter cake shall be dried in drying procedure. The production capacity of filtering and scrubbing is improved, the energy consumption is reduced, and the filtering and scrubbing effect is improved after process improvement.%阐述了氯化法钛白粉后处理生产工序中压滤洗涤系统的工艺改进,使用一种新型的隔膜压滤机和一种新的过滤洗涤方式对包膜后的钛白粉浆料进行过滤洗涤脱水,最终形成合格的滤饼供到干燥工序进行干燥.经过改进后,提高过滤洗涤的生产能力,降低能耗,提高过滤洗涤的效果.

  7. Manufacturing of robust natural fiber preforms utilizing bacterial cellulose as binder.

    Science.gov (United States)

    Lee, Koon-Yang; Shamsuddin, Siti Rosminah; Fortea-Verdejo, Marta; Bismarck, Alexander

    2014-01-01

    A novel method of manufacturing rigid and robust natural fiber preforms is presented here. This method is based on a papermaking process, whereby loose and short sisal fibers are dispersed into a water suspension containing bacterial cellulose. The fiber and nanocellulose suspension is then filtered (using vacuum or gravity) and the wet filter cake pressed to squeeze out any excess water, followed by a drying step. This will result in the hornification of the bacterial cellulose network, holding the loose natural fibers together. Our method is specially suited for the manufacturing of rigid and robust preforms of hydrophilic fibers. The porous and hydrophilic nature of such fibers results in significant water uptake, drawing in the bacterial cellulose dispersed in the suspension. The bacterial cellulose will then be filtered against the surface of these fibers, forming a bacterial cellulose coating. When the loose fiber-bacterial cellulose suspension is filtered and dried, the adjacent bacterial cellulose forms a network and hornified to hold the otherwise loose fibers together. The introduction of bacterial cellulose into the preform resulted in a significant increase of the mechanical properties of the fiber preforms. This can be attributed to the high stiffness and strength of the bacterial cellulose network. With this preform, renewable high performance hierarchical composites can also be manufactured by using conventional composite production methods, such as resin film infusion (RFI) or resin transfer molding (RTM). Here, we also describe the manufacturing of renewable hierarchical composites using double bag vacuum assisted resin infusion. PMID:24893649

  8. Manufacturing Of Robust Natural Fiber Preforms Utilizing Bacterial Cellulose as Binder

    Science.gov (United States)

    Lee, Koon-Yang; Shamsuddin, Siti Rosminah; Fortea-Verdejo, Marta; Bismarck, Alexander

    2014-01-01

    A novel method of manufacturing rigid and robust natural fiber preforms is presented here. This method is based on a papermaking process, whereby loose and short sisal fibers are dispersed into a water suspension containing bacterial cellulose. The fiber and nanocellulose suspension is then filtered (using vacuum or gravity) and the wet filter cake pressed to squeeze out any excess water, followed by a drying step. This will result in the hornification of the bacterial cellulose network, holding the loose natural fibers together. Our method is specially suited for the manufacturing of rigid and robust preforms of hydrophilic fibers. The porous and hydrophilic nature of such fibers results in significant water uptake, drawing in the bacterial cellulose dispersed in the suspension. The bacterial cellulose will then be filtered against the surface of these fibers, forming a bacterial cellulose coating. When the loose fiber-bacterial cellulose suspension is filtered and dried, the adjacent bacterial cellulose forms a network and hornified to hold the otherwise loose fibers together. The introduction of bacterial cellulose into the preform resulted in a significant increase of the mechanical properties of the fiber preforms. This can be attributed to the high stiffness and strength of the bacterial cellulose network. With this preform, renewable high performance hierarchical composites can also be manufactured by using conventional composite production methods, such as resin film infusion (RFI) or resin transfer molding (RTM). Here, we also describe the manufacturing of renewable hierarchical composites using double bag vacuum assisted resin infusion. PMID:24893649

  9. Bacterial Cellulose-Hydroxyapatite Nanocomposites for Bone Regeneration

    OpenAIRE

    Saska, S.; H.S. Barud; Gaspar, A. M. M.; Marchetto, R.; Ribeiro, S. J. L.; Y. Messaddeq

    2011-01-01

    The aim of this study was to develop and to evaluate the biological properties of bacterial cellulose-hydroxyapatite (BC-HA) nanocomposite membranes for bone regeneration. Nanocomposites were prepared from bacterial cellulose membranes sequentially incubated in solutions of CaCl2 followed by Na2HPO4. BC-HA membranes were evaluated in noncritical bone defects in rat tibiae at 1, 4, and 16 weeks. Thermogravimetric analyses showed that the amount of the mineral phase was 40%–50% of the total wei...

  10. A comparison of the performance of aromatic polyamide and cellulose acetate reverse osmosis membrane on the regeneration of secondary effluents; Comparacion del funcionamiento de membranas de osmosis inversa de poliamida aromatica y acetato de celulosa en la regeneracion de efluentes secundarios

    Energy Technology Data Exchange (ETDEWEB)

    Lopez Ramirez, J. A.; Carrasco Vega, M.; Sales Marquez, D.; Quiroga Alonso, J. M.

    2002-07-01

    The application of reverse osmosis in regenerating waste waters has aroused a great deal of interest, although relatively few experiments using this technique have so far been carried out in Spain. In 1994, an experimental pilot plant was built at the La Barrosa waste water treatment plant in Chiclana de la Frontera in the province of Cadiz. This pilot plant with a capacity of 100 m''3/day, was equipped with various advanced treatments, most notably reverse osmosis, for treating urban waste waters for re-use. Since this pilot plant was built, various experiments have been carried out employing cellulose acetate (Hydranautics) and different types of Spanish-made aromatic polyamide membranes (Pridesa). Each type of membrane proposed different operating characteristics and feed-water requirements making each one suitable for a particular purpose. In this study, the secondary effluents was subjected to different kinds of treatment-called intense treatment, moderate treatment and minimum treatment-before reaching the reverse osmosis unit, which influenced the conditions in which the membranes operated. Following each type of treatment, the waters entering and leaving the installation were analysed to evaluate the quality of the final effluent and the effectiveness of the treatment carried out. The quality was extremely good in all the permeate samples analysed, almost irrespective of the type of treatment applied. It was also found that the cellulose acetate membranes tended to become less dirty than the aromatic polyamide membranes,due to their surface morphology. Nevertheless, the polyamide membranes have various advantages allowing them to be used in a wide range of applications at a lower energy cost. (Author) 8 refs.

  11. Rapid Quantification of Bacteria in Infected Root Canals Using Fluorescence Reagents and a Membrane Filter: A Pilot Study on Its Clinical Application to the Evaluation of the Outcomes of Endodontic Treatment

    Directory of Open Access Journals (Sweden)

    Takuichi Sato

    2012-01-01

    Full Text Available Objective. The bacterial examination has been performed during the course of the root canal treatment. In the present pilot study, the new developed method, using fluorescence reagents and a membrane filter, was applied to the detection and quantification of bacteria in infected root canals, in order to evaluate the outcomes of the treatment. Methods. Six infected root canals with periapical lesions from 5 subjects were included. Informed consent was obtained from all subjects (age ranges, 23–79 years. Samples from infected root canals were collected at the beginning of the treatment (termed #25 First, the end of the first day of treatment (termed #55 First, and the next appointment day (termed #55 Second. Then, the bacterial count (CFU was measured using fluorescence reagents (4′,6′-diamidino-2-phenylindole and propidium iodide and the polycarbonate membrane filter by Bioplorer. Results. The mean ± SD of CFU in the sample of “#25 First” was (1.0±1.4×105. As the root canal treatment progressed, the CFU decreased as 7.9×103 (#55 First and 4.3×102 (#55 Second. Conclusion. In the present pilot study, rapid detection and quantification of bacteria in infected root canals were found to be successfully performed using fluorescence reagents and a membrane filter (Bioplorer analysis.

  12. Endotoxin removal by charge-modified filters.

    OpenAIRE

    Gerba, C P; Hou, K

    1985-01-01

    The effects of positively charged nylon and depth (cellulose-diatomaceous earth) filters on endotoxin removal from various solutions were evaluated. The charged filter media removed significant amounts of Escherichia coli and natural endotoxin from tap water, distilled water, sugars, and NaCl solutions; no significant removal of endotoxin was observed with negatively charged filter media. The extent of removal was influenced by pH, the presence of salts, and organic matter. Such media may be ...

  13. Use of biosynthetic cellulose membrane in the guided tissue regeneration/ Uso de membrana biossintética a base de celulose na regeneração tecidual guiada

    Directory of Open Access Journals (Sweden)

    Cláudia Valéria Seullner Brandão

    2007-08-01

    Full Text Available Guided Tissue Regeneration (GTR is a regenerative treatment modality that requires the placement of a physical barrier over a bone defect in such a way that the proliferation of the surrounding soft tissues into the barrier-protected area is prevented. Thereby in the guided osseous regeneration allowing boneforming cells from the existent bone edges to invade the space and produce bone. The physical barriers should be biocompatible, allow cellular occlusion, maintain adequate space, tissue integration and facility in the application. They can be occlusive or permeable, absorbable or non-absorbable. Among various types of physical barriers in the market, the cellulose biosynthetic membrane is emphasizing by the necessary characteristics for GTR and to be a national product developed in low cost.A Regeneração Tecidual Guiada (RTG consiste numa modalidade de tratamento regenerativo que requer a colocação de uma barreira física sobre o defeito ósseo, de modo que a proliferação de tecidos moles adjacentes para dentro da área protegida seja evitada. Assim, a regeneração óssea guiada permite que células com potencial osteogênico das margens ósseas existentes invadam o espaço criado e produzam osso. As barreiras físicas devem ser biocompatíveis, permitir a oclusão celular, manutenção do espaço, integração tecidual e facilidade de uso. Podem ser oclusivas ou permeáveis, absorvíveis ou nãoabsorvíveis. Dentre os vários tipos de barreiras físicas existentes no mercado, a membrana biossintética a base de celulose vem se destacando, pois, além de possuir as características necessárias para a RTG, trata-se de um produto nacional desenvolvido a baixos custos.

  14. Manufacturing Of Robust Natural Fiber Preforms Utilizing Bacterial Cellulose as Binder

    OpenAIRE

    Lee, K-Y; Shamsuddin, S. R.; Fortea-Verdejo, M.; Bismarck, A.

    2014-01-01

    A novel method of manufacturing rigid and robust natural fiber preforms is presented here. This method is based on a papermaking process, whereby loose and short sisal fibers are dispersed into a water suspension containing bacterial cellulose. The fiber and nanocellulose suspension is then filtered (using vacuum or gravity) and the wet filter cake pressed to squeeze out any excess water, followed by a drying step. This will result in the hornification of the bacterial cellulose network, hold...

  15. 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.

  16. Selection of filter media in alpha air monitors for emergency environmental monitoring

    International Nuclear Information System (INIS)

    We have developed an alpha air monitor which is possible to measure rapidly and sensitively the concentrations of airborne alpha-emitting particles, such as plutonium, for the environmental monitoring at an accident of nuclear reprocessing plant. The monitor is designed to collect airborne alpha-emitting particles by drawing the ambient air through a filter and to detect the activity by alpha spectroscopy. In order to achieve high-sensitive measurements, selection of a suitable filter used in the monitor is considerably important. The most important requirement for the filter is that it has a high surface collection efficiency to obtain the sharpness of the alpha energy spectrum. This makes it easy to distinguish the alpha-ray peak of plutonium from the alpha spectrum of naturally occurring radon decay products in the environment. And the filter is also desired to have low resistance of the air flow so that particles can be collected at a high flowrate. We have made a comparison of the surface collection efficiency and pressure drop for the various filters. Types of the test filters, most of which are commercially available in Japan, were glass fiber, cellulose-glass fiber, membrane and so on. The surface collection efficiency has been evaluated by the following two indices. One was the sharpness of alpha-ray energy peaks of thoron decay products generated in a laboratory and collected in the fibers. The other was the background counts of radon decay products in a plutonium region by measuring alpha-ray energy spectrum of radon decay products collected in the filters by sampling of dust in the atmosphere. It was found that the PTFE (polytetrafluoroethylene) membrane filter with backing had a high surface collection efficiency and low pressure drop. The results of the test are described in detail in this paper. (author)

  17. Denitrification in Membrane Bioreactors

    OpenAIRE

    Fonseca, Anabela Duarte

    1999-01-01

    Three membrane bioreactors, a low flux filter (LFF), a diafilter (DF), and an ion-exchange (IE) membrane bioreactor were used to treat water polluted with 50 ppm-N nitrate. The three systems were compared in terms of removal efficiency of nitrate, operational complexity, and overall quality of the treated water. In the low flux filter (LFF) membrane bioreactor an hemo-dialysis hollow fiber module was used and operated continuously for 29 days with a constant flux of permeate. The perform...

  18. 细菌纤维素膜作为生物支架构建组织工程角膜上皮的可行性研究%Feasibility of bacterial cellulose membrane as biological scaffold for construction of tissue engineering corneal epithelium

    Institute of Scientific and Technical Information of China (English)

    曹静洁; 张琛; 赵少贞; 万怡灶; 胡达

    2016-01-01

    Background Corneal transplantation is a primary method for the treatment of serious corneal diseases, but its application is limited because of the shortage of corneal donor.The study on tissue engineering corneal epithelium provides a new approach to corneal transplantation, and the biological scaffold materials for tissue engineering corneal epithelium is an issue of increasing concern.Bacterial cellulose membrane has been used in medical field,but its application in tissue engineering corneal epithelium deserves more researching.Objective This study was to evaluate the biocompatibility of bacterial cellulose membrane as a biological scaffold of tissue engineering corneal epithelium.Methods Corneal epithelium was isolated from 1 month-old New Zealand White rabbit.Corneal epithelial cells were cultured using explant method and identified by detecting the CK-3 expression using immunofluorescence technique.The second generation ceils were inoculated on bacterial cellulose membrane and culture plate, respectively, and the growth status of the cells were examined and compared under the optical microscope.The cell activity/toxicity test was performed by LIVE/DEAD cell staining kit at the third day after inoculation to evaluate the survival rate.The ultrastructure of the cell surface was examined under the scanning electron microscope.The study was performed in accordance with the ARVO Statement.Results Rabbit corneal epithelial cells grew well 1 week after primarily cultured with a cobblestone-like appearance and positive response for CK3 antibody.The cells on the bacterial cellulose membrane presented a round shape and regular arrangement and showed the green fluorescence for LIVE/DEAD test,with the survival rate 100%.Abundant leafy protrusion, microvilli and intercellular junction were seen under the scanning electron microscope.In addition, mitosis phase of cells and many filopodia between the cells and bacterial cellulose membrane were also exhibited

  19. Process Dependence of Cellulose Nanofiber Fabrication

    Science.gov (United States)

    Henderson, Doug; Zhang, Xin; Mao, Yimin; Jang, Soo-Hwan; Hu, Liangbing; Briber, Robert; Wang, Howard

    Cellulose nanofibers (CNF) are the most abundant natural nanomaterial on earth with potential applications in renewable energy, polymer nanocomposites and flexible electronics. CNF can be produced through TEMPO oxidation which separates the hierarchical structure of cellulose fibers into smaller micro- and nanofibers by altering their surface chemistry, inducing a repulsive electrostatic charge on the fibers. This work will examine the structural evolution of CNF during production. Samples were prepared by removing and quenching aliquots during the TEMPO reaction. The fibers were washed, filtered and re-dispersed into D2O for small angle neutron scattering (SANS) measurements. The SANS data was analyzed to track the changes in the CNF structure as a function of reaction time.

  20. 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.

  1. 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.

  2. Synthesis of cellulose acetate and carboxymethylcellulose from sugarcane straw.

    Science.gov (United States)

    Candido, R G; Gonçalves, A R

    2016-11-01

    Sugarcane straw (SCS) is a raw material with high potential for production of cellulose derivatives due to its morphology and structure. The proposal of this work was to synthesize cellulose acetate (CA) and carboxymethylcellulose (CMC) from sugarcane straw cellulose, and applied the CA in the preparation of a membrane. The cellulose extraction was carried out in four steps. Firstly, SCS was treated with H2SO4 (10% v/v) followed by NaOH (5% w/v) treatment. Subsequently, a chelating process was performed before ending the extraction process with chemical bleaching using H2O2 (5% v/v). The extracted cellulose was employed in the obtainment of CA and CMC. The CA presented a degree of substitution (DS) of 2.72. Its FTIR spectrum showed that practically all hydroxyl groups were replaced by acetate groups. The membrane synthesized from CA was dense and homogeneous. The presence of small particles on the top and bottom surfaces decreased the mechanical resistance of the membrane. The CMC presented a low DS (0.4) demonstrating the carboxymethylation reaction was not very effective due to the presence of lignin. These results proved that SCS can be utilized in the synthesis of CA and CMC. PMID:27516319

  3. Membranes and Films from Polymers.

    Science.gov (United States)

    Blumberg, Avrom A.

    1986-01-01

    Provides background information on polymeric films and membranes including production methods, special industrial and medical applications, laboratory preparation, and an experimental investigation of a porous cellulose acetate membrane. Presents a demonstration to distinguish between high- and low-density polyethylene. (JM)

  4. Membrane humidity control investigation

    Science.gov (United States)

    Elam, J.; Ruder, J.; Strumpf, H.

    1974-01-01

    The basic performance data on a hollow fiber membrane unit that removes water from a breathing gas loop by diffusion is presented. Using available permeability data for cellulose acetate, a preliminary design was made of a dehumidifier unit that would meet the problem statement.

  5. 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

  6. Electrochemical synthesis of cellulose mesylate

    Science.gov (United States)

    Khidirov, Sh Sh; Akhmedov, M. A.; Khibiev, H. S.

    2016-04-01

    The article deal with the possibility anode modification of cellulose to form its ester - mesylate by voltametric measurement method and preparative electrosynthesis on a platinum electrode in the system cellulose - dimethyl sulfoxide - methanesulfonic

  7. Structure of cellulose acetobacter xylinum

    International Nuclear Information System (INIS)

    The data are presented on optimization of cellulose synthesis by Acetobacter xylinum (strain VKM V-880) and the structural characteristics of A. xylinum cellulose gel film synthesized during static cultivation. The structural changes caused by the removal of water from gel films are established and the structural organization of macromolecular chains in cellulose A. xylinum is studied

  8. Design and development of high performance panel air filter with experimental evaluation and analysis of filter media pleats

    OpenAIRE

    Sagar R. Patil; Prof. Sachin V. Lomte

    2015-01-01

    In automobile vehicles mostly plastic molded panel filters used for the purpose of engine air filtration. Fibrous structured cellulose media were being used with different permeability’s according to requirement of rated air flow rate required for the engine. To optimize the filter pleat design of automotive panel air filter, it is important to study correlation of pressure drop, dust holding capacity & efficiency. The main role of a filter is to provide least pressure drop with h...

  9. Pattern formation of cortical microtubules and cellulose microfibrils

    NARCIS (Netherlands)

    Lindeboom, J.J.

    2012-01-01

    In this thesis we study the roles of microtubules at the plasma membrane and the cellulose microfibrils in the cell wall and how they are organized. This topic is introduces in chapter 1. In chapter 2 we study the formation of the transverse cortical microtubule array that is characteristic for elon

  10. Degradation of cellulose in irradiated wood and purified celluloses

    International Nuclear Information System (INIS)

    The degradation of cellulose chains in Pinus radiata and Eucalyptus regnans given small gamma-radiation doses has been studied. Scission yields showed marked dose-dependency effects, of which some appear to be due to an inherent dose-dependency exhibited by cellulose itself, and others indicate a protective action of some natural wood constituents. A uniform treatment of viscometry data reported by various workers who have studied radiation-induced degradation of purified cellulose materials, has been used to enable their scission results to be compared with each other and with those for natural wood cellulose of various dose levels. Generally, cellulose in wood is less degraded by radiation than is purified cellulose. However, with Eucalyptus regnans remarkably high scission yields, significantly higher than expected for purified cellulose, were observed at dose levels of 0.5-1.0 x 104Gy. The relevance of these results to changes in pulp yield following irradiation of wood chips, is briefly discussed. (author)

  11. 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

  12. Cysticercosis cellulose cutis

    Directory of Open Access Journals (Sweden)

    Inamadar Arun

    2001-01-01

    Full Text Available A woman aged 30 years with solitary lesion of cysticercosis cellulose cutis is reported. Cutaneous cysticerci are often a pointer to the involvement of internal organs. Our patient was a pure vegetarian so, probable mode of infection may be ingestion of contaminated vegetables, where the practice of using pig feces as manure is prevalent.

  13. Derivatives of Oxidized Cellulose

    Czech Academy of Sciences Publication Activity Database

    Taubner, T.; Sobek, Jiří; Havelka, P.; Kvasnička, F.; Synytsya, A.; Čopíková, J.

    Praha : Česká společnost chemická, 2009, s. 777. ISSN 0009-2770. [International Conference on Polysaccharides-Glycoscience 2009 /5./. Praha (CZ), 11.11.2009-13.11.2009] Institutional research plan: CEZ:AV0Z40720504 Keywords : cellulose * reaction progress * chromatography Subject RIV: CI - Industrial Chemistry, Chemical Engineering

  14. Microwave Filters

    OpenAIRE

    Zhou, Jiafeng

    2010-01-01

    The general theory of microwave filter design based on lumped-element circuit is described in this chapter. The lowpass prototype filters with Butterworth, Chebyshev and quasielliptic characteristics are synthesized, and the prototype filters are then transformed to bandpass filters by lowpass to bandpass frequency mapping. By using immitance inverters ( J - or K -inverters), the bandpass filters can be realized by the same type of resonators. One design example is given to verify the theory ...

  15. Human neutrophil elastase peptide sensors conjugated to cellulosic and nanocellulosic materials: part I, synthesis and characterization of fluorescent analogs

    Science.gov (United States)

    Here we describe the synthesis and characterization of peptide conjugated cellulose and nanocellulose materials as sensors for fluorescent detection of human neutrophil elastase (HNE). The cellulose sensor surfaces selected are filter paper (FP) and print cloth (PC) fabric, which are composed of pro...

  16. A kinetic study of Trichoderma reesei Cel7B catalyzed cellulose hydrolysis.

    Science.gov (United States)

    Song, Xiangfei; Zhang, Shujun; Wang, Yefei; Li, Jingwen; He, Chunyan; Yao, Lishan

    2016-06-01

    One prominent feature of Trichoderma reesei (Tr) endoglucanases catalyzed cellulose hydrolysis is that the reaction slows down quickly after it starts (within minutes). But the mechanism of the slowdown is not well understood. A structural model of Tr- Cel7B catalytic domain bound to cellulose was built computationally and the potentially important binding residues were identified and tested experimentally. The 13 tested mutants show different binding properties in the adsorption to phosphoric acid swollen cellulose and filter paper. Though the partitioning parameter to filter paper is about 10 times smaller than that to phosphoric acid swollen cellulose, a positive correlation is shown for two substrates. The kinetic studies show that the reactions slow down quickly for both substrates. This slowdown is not correlated to the binding constant but anticorrelated to the enzyme initial activity. The amount of reducing sugars released after 24h by Cel7B in phosphoric acid swollen cellulose, Avicel and filter paper cellulose hydrolysis is correlated with the enzyme activity against a soluble substrate p-nitrophenyl lactoside. Six of the 13 tested mutants, including N47A, N52D, S99A, N323D, S324A, and S346A, yield ∼15-35% more reducing sugars than the wild type (WT) Cel7B in phosphoric acid swollen cellulose and filter paper hydrolysis. This study reveals that the slowdown of the reaction is not due to the binding of the enzyme to cellulose. The activity of Tr- Cel7B against the insoluble substrate cellulose is determined by the enzyme's capability in hydrolyzing the soluble substrate. PMID:27178789

  17. Pembuatan Membran Selulosa Bakteri Coating Kitosan - Kolagen Untuk Aplikasi Gtr ( Guide Tissue Regeneration ) Sebagai Pembalut Luka Pada Mencit (Mus Musculus)Secara In Vivo

    OpenAIRE

    Humaira, Nadia Maulida

    2015-01-01

    Bacterial cellulose produced from the fermentation process used in the development of Acetobacter xylinum to increase efficiency of bacterial cellulose one of them in the biomedical field , is membrane . This study aimed to determine the effect concentration of chitosan-collagen, see optimum characterization of bacterial cellulose membrane coating of chitosan-collagen that can be used in the application as wound dressings in mice by In Vivo. Preparation of the bacterial cellulose membrane usi...

  18. Cyclic diguanylic acid and cellulose synthesis in Agrobacterium tumefaciens

    International Nuclear Information System (INIS)

    The occurrence of the novel regulatory nucleotide bis(3',5')-cyclic diguanylic acid (c-di-GMP) and its relation to cellulose biogenesis in the plant pathogen Agrobacterium tumefaciens was studied. c-di-GMP was detected in acid extracts of 32P-labeled cells grown in various media, and an enzyme responsible for its formation from GTP was found to be present in cell-free preparations. Cellulose synthesis in vivo was quantitatively assessed with [14C]glucose as a tracer. The organism produced cellulose during growth in the absence of plant cells, and this capacity was retained in resting cells. Synthesis of a cellulosic product from UDP-glucose in vitro with membrane preparations was markedly stimulated by c-di-GMP and its precursor GTP and was further enhanced by Ca2+. The calcium effect was attributed to inhibition of a c-di-GMP-degrading enzyme shown to be present in the cellulose synthase-containing membranes

  19. Optimization of upstream and development of cellulose hydrolysis process for cellulosic bio-ethanol production

    International Nuclear Information System (INIS)

    The purpose of this project is optimization of upstream and development of cellulose hydrolysis process for cellulosic bio-ethanol production. The 2nd year Research scope includes: 1) Optimization of pre-treatment conditions for enzymatic hydrolysis of lignocellulosic biomass and 2) Demonstration of enzymatic hydrolysis by recombinant enzymes. To optimize the pretreatment, we applied two processes: a wet process (wet milling + popping), and dry process (popping + dry milling). Out of these, the wet process presented the best glucose yield with a 93.1% conversion, while the dry process yielded 69.6%, and the unpretreated process yielded <20%. The recombinant cellulolytic enzymes showed very high specific activity, about 80-1000 times on CMC and 13-70 times on filter paper at pH 3.5 and 55 .deg. C

  20. Water-repellent cellulose fiber networks with multifunctional properties.

    Science.gov (United States)

    Bayer, Ilker S; Fragouli, Despina; Attanasio, Agnese; Sorce, Barbara; Bertoni, Giovanni; Brescia, Rosaria; Di Corato, Riccardo; Pellegrino, Teresa; Kalyva, Maria; Sabella, Stefania; Pompa, Pier Paolo; Cingolani, Roberto; Athanassiou, Athanassia

    2011-10-01

    We demonstrate a simple but highly efficient technique to introduce multifunctional properties to cellulose fiber networks by wetting them with ethyl-cyanoacrylate monomer solutions containing various suspended organic submicrometer particles or inorganic nanoparticles. Solutions can be applied on cellulosic surfaces by simple solution casting techniques or by dip coating, both being suitable for large area applications. Immediately after solvent evaporation, ethyl-cyanoacrylate starts cross-linking around cellulose fibers under ambient conditions because of naturally occurring surface hydroxyl groups and adsorbed moisture, encapsulating them with a hydrophobic polymer shell. Furthermore, by dispersing various functional particles in the monomer solutions, hydrophobic ethyl-cyanoacrylate nanocomposites with desired functionalities can be formed around the cellulose fibers. To exhibit the versatility of the method, cellulose sheets were functionalized with different ethyl-cyanoacrylate nanocomposite shells comprising submicrometer wax or polytetrafluoroethylene particles for superhydophobicity, MnFe(2)O(4) nanoparticles for magnetic activity, CdSe/ZnS quantum dots for light emission, and silver nanoparticles for antimicrobial activity. Morphological and functional properties of each system have been studied by scanning and transmission electron microscopy, detailed contact angle measurements, light emission spectra and E. coli bacterial growth measurements. A plethora of potential applications can be envisioned for this technique, such as food and industrial packaging, document protection, catalytic cellulosic membranes, textronic (electrofunctional textiles), electromagnetic devices, authentication of valuable documents, and antimicrobial wound healing products to name a few. PMID:21902239

  1. Water Filters

    Science.gov (United States)

    1993-01-01

    The Aquaspace H2OME Guardian Water Filter, available through Western Water International, Inc., reduces lead in water supplies. The filter is mounted on the faucet and the filter cartridge is placed in the "dead space" between sink and wall. This filter is one of several new filtration devices using the Aquaspace compound filter media, which combines company developed and NASA technology. Aquaspace filters are used in industrial, commercial, residential, and recreational environments as well as by developing nations where water is highly contaminated.

  2. Evaluation of Potential Fungal Species for the in situ Simultaneous Saccharification and Fermentation (SSF) of Cellulosic Material

    OpenAIRE

    van Leeuwen, J.; Vincent, M; Pometto III, A. L.

    2011-01-01

    Three fungal species were evaluated for their abilities to saccharify pure cellulose. The three species chosen represented three major wood-rot molds; brown rot (Gloeophyllum trabeum), white rot (Phanerochaete chrysosporium) and soft rot (Trichoderma reesei). After solid state fermentation of the fungi on the filter paper for four days, the saccharified cellulose was then fermented to ethanol by using Saccharomyces cerevisiae. The efficiency of the fungal species in saccharifying the filter p...

  3. 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. PMID:27462405

  4. Synthesis and characterization of cellulose derivatives obtained from bacterial cellulose

    International Nuclear Information System (INIS)

    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 13C. 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)

  5. 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

    2016-01-01

    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. PMID:27345599

  6. Arabidopsis thaliana KORRIGAN1 protein: N-glycan modification, localization, and function in cellulose biosynthesis and osmotic stress responses

    OpenAIRE

    von Schaewen, Antje; Rips, Stephan; Jeong, In Sil; Koiwa, Hisashi

    2015-01-01

    Plant cellulose biosynthesis is a complex process involving cellulose-synthase complexes (CSCs) and various auxiliary factors essential for proper orientation and crystallinity of cellulose microfibrils in the apoplast. Among them is KORRIGAN1 (KOR1), a type-II membrane protein with multiple N-glycans within its C-terminal cellulase domain. N-glycosylation of the cellulase domain was important for KOR1 targeting to and retention within the trans-Golgi network (TGN), and prevented accumulation...

  7. Experimental study of filter cake formation on different filter media

    International Nuclear Information System (INIS)

    Removal of particulate matter from gases generated in the process industry is important for product recovery as well as emission control. Dynamics of filtration plant depend on operating conditions. The models, that predict filter plant behaviour, involve empirical resistance parameters which are usually derived from limited experimental data and are characteristics of the filter media and filter cake (dust deposited on filter medium). Filter cake characteristics are affected by the nature of filter media, process parameters and mode of filter regeneration. Removal of dust particles from air is studied in a pilot scale jet pulsed bag filter facility resembling closely to the industrial filters. Limestone dust and ambient air are used in this study with two widely different filter media. All important parameters like pressure drop, gas flow rate, dust settling, are recorded continuously at 1s interval. The data is processed for estimation of the resistance parameters. The pressure drop rise on test filter media is compared. Results reveal that the surface of filter media has an influence on pressure drop rise (concave pressure drop rise). Similar effect is produced by partially jet pulsed filter surface. Filter behaviour is also simulated using estimated parameters and a simplified model and compared with the experimental results. Distribution of cake area load is therefore an important aspect of jet pulse cleaned bag filter modeling. Mean specific cake resistance remains nearly constant on thoroughly jet pulse cleaned membrane coated filter bags. However, the trend can not be confirmed without independent cake height and density measurements. Thus the results reveal the importance of independent measurements of cake resistance. (author)

  8. Interactions of microfibrillated cellulose and cellulosic fines with cationic polyelectrolytes

    OpenAIRE

    Taipale, Tero

    2010-01-01

    The overall aim of this work was to produce and characterize different types of cellulosic fines and microfibrillated cellulose; to study their interactions with high molar mass cationic polyelectrolytes; and to demonstrate novel examples of their utilization. The work was performed, and its results discussed mainly from papermaking point of view, but the results are also well applicable in other fields of industry. Cellulosic fines are an essential component of papermaking fiber suspens...

  9. Three-dimensional cellulose sponge: Fabrication, characterization, biomimetic mineralization, and in vitro cell infiltration.

    Science.gov (United States)

    Joshi, Mahesh Kumar; Pant, Hem Raj; Tiwari, Arjun Prasad; Maharjan, Bikendra; Liao, Nina; Kim, Han Joo; Park, Chan Hee; Kim, Cheol Sang

    2016-01-20

    In this study, cellulose based scaffolds were produced by electrospinning of cellulose acetate (CA) solution followed by its saponification with NaOH/ethanol system for 24h. The resulting nonwoven cellulose mat was treated with sodium borohydride (SB) solution. In situ hydrolysis of SB solution into the pores of the membrane produced hydrogen gas resulting a three-dimensional (3D) cellulose sponge. SEM images demonstrated an open porous and loosely packed fibrous mesh compared to the tightly packed single-layered structure of the conventional electrospun membrane. 3D cellulose sponge showed admirable ability to nucleate bioactive calcium phosphate (Ca-P) crystals in simulated body fluid (SBF) solution. SEM-EDX and X-ray diffraction studies revealed that the minerals deposited on the nanofibers have the nonstoichiometric composition similar to that of hydroxyapatite, the mineralized component of the bone. 3D cellulose sponge exhibited the better cell infiltration, spreading and proliferation compared to 2D cellulose mat. Therefore, a facile fabrication of 3D cellulose sponge with improved mineralization represents an innovative strategy for the bone tissue engineering applications. PMID:26572341

  10. Homemade lyophilized cross linking amniotic sustained-release drug membrane with anti-scarring role after filtering surgery in rabbit eyes

    Science.gov (United States)

    Li, Wan; Chen, Wen-Jian; Liu, Wei; Liang, Liang; Zhang, Ming-Chang

    2012-01-01

    AIM To investigate the antifibrotic effect of the freeze-dried bilayered fibrin-binding amniotic membrane as a drug delivery system on glaucoma surgery in rabbit model. The aim of this study was to prepare a novel local delivery system for the sustained and controllable release of 5-Fu. METHODS Twenty-four Japanese white rabbits were randomized into three groups: the experimental group (ocular trabeculectomy in combination with 5-Fu loaded freeze-dried bilayered fibrin-binding amniotic membrane transplantation), the control group (ocular trabeculectomy in combination with 5-Fu) and the blank group (single trabeculectomy). HE staining, massion staining and immunohistochemistry for α-SMA were performed on days 7, 14, 21 and 30 following surgery. The concentration of 5-Fu in rabbit aqueous humor was examined by high performance liquid chromatography (HPLC) 3 days after the surgery. RESULTS Statistical differences were noted in intraocular pressure among groups on day 7, 14, 21 and 30 following surgery. Histology further demonstrated that trabeculectomy in combination with freeze-dried bilayered fibrin-binding amniotic membrane yielded well wound healing and no scar formation and was beneficial for long term effect. CONCLUSION HPLC showed a good slow-release effect with freeze-dried bilayered fibrin-binding amniotic membrane. PMID:23166864

  11. Interfacial Properties of Ethyl Cellulose/Cellulose Acetate Blends by HPLC

    Institute of Scientific and Technical Information of China (English)

    GAO Su-lian; ZHOU Ning-guo; ZHANG Xiu-zhen; ZHANG Wei

    2007-01-01

    The high performance liquid chromatography method (HPLC) with ethyl cellulose/cellulose acetate (EC/CA)blends and EC as column packing material, and small molecular weight compound as probe molecules was employed to measure the retention volume (VR) and equilibrium distribution coefficient (K) of both inorganic and organic solutes. The interfacial separation properties of EC/CA blends were characterized by the HPLC data. The effects of the blends on the inteffacial adsorption properties, hydrophilicity, affinity, polar and non-polar parameters of EC membrane materials were studied subsequently. The research results indicate that the interfacial adsorption properties and hydrophilicity of EC have been improved by solution blending with CA. The alloys are superior to EC in the separation efficiency for non-dissociable polar organic solute. The EC/CA alloy (80:20, ω) is suitable for desalting and desaccharifying.

  12. Novel oil resistant cellulosic materials

    OpenAIRE

    Aulin, Christian

    2009-01-01

    The aim of this study has been to prepare and characterise oil resistant cellulosic materials, ranging from model surfaces to papers and aerogels. The cellulosic materials were made oil resistant by chemical and topographic modifications, based on surface energy, surface roughness and barrier approaches. Detailed wetting studies of the prepared cellulosic materials were made using contact angle measurements and standardised penetration tests with different alkanes and oil mixtures. A signific...

  13. Optimal filtering

    CERN Document Server

    Anderson, Brian D O

    2005-01-01

    This graduate-level text augments and extends beyond undergraduate studies of signal processing, particularly in regard to communication systems and digital filtering theory. Vital for students in the fields of control and communications, its contents are also relevant to students in such diverse areas as statistics, economics, bioengineering, and operations research.Topics include filtering, linear systems, and estimation; the discrete-time Kalman filter; time-invariant filters; properties of Kalman filters; computational aspects; and smoothing of discrete-time signals. Additional subjects e

  14. 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.

  15. Polyethylenimine surface layer for enhanced virus immobilization on cellulose

    Science.gov (United States)

    Tiliket, Ghania; Ladam, Guy; Nguyen, Quang Trong; Lebrun, Laurent

    2016-05-01

    Thin regenerated cellulose films are prepared by hydrolysis of cellulose acetate (CA). A polycation, namely polyethylenimine (PEI), is then adsorbed onto the films. From QCM-D analysis, PEI readily adsorbs from a 0.1% w/v solution in NaCl 0.2 M (ca. 100 ng cm-2). Further PEI adsorption steps at higher PEI concentrations induce a linear growth of the PEI films, suggesting that free adsorption sites still exist after the initial adsorption. The adsorbed PEI chains are resistant to variations of the ionic strength up to NaCl 1 M. Promisingly, the adsorption of T4D bacteriophages are 15-fold more efficient onto the PEI-treated, compared to the native regenerated cellulose films, as measured by QCM-D. This confirms the strong affinity between the negatively charged viruses and PEI, even at low PEI concentration, probably governed by strong electrostatic attractive interactions. This result explains the remarkable improvement of the affinity of medical masks for virus droplets when one of their cellulose layers was changed by two-PEI-functionalized cellulose-based filters.

  16. Effect of sonochemical synthesized TiO2 nanoparticles and coagulation bath temperature on morphology, thermal stability and pure water flux of asymmetric cellulose acetate membranes prepared via phase inversion method

    Directory of Open Access Journals (Sweden)

    Abedini Reza

    2012-01-01

    Full Text Available In this study, asymmetric pure CA and CA/ TiO2 composite membranes were prepared via phase inversion by dispersing TiO2 nanopaticles in the CA casting solutions induced by immersion precipitation in water coagulation bath. TiO2 nanoparticles, which were synthesized by the sonochemical method, were added into the casting solution with different concentrations. Effects of TiO2 nanoparticles concentration (0 wt. %, 5wt.%, 10wt.%, 15wt.%, 20wt.% and 25wt.% and coagulation bath temperature (CBT= 25°C, 50°C and 75°C on morphology, thermal stability and pure water flux (PWF of the prepared membranes were studied and discussed. Increasing TiO2 concentration in the casting solution film along with higher CBT resulted in increasing the membrane thickness, water content (WC, membrane porosity and pure water flux (PWF, also these changes facilitate macrovoids formation. Thermal gravimetric analysis (TGA shows that thermal stability of the composite membranes were improved by the addition of TiO2 nanopaticles. Also TGA results indicated that increasing CBT in each TiO2 concentration leads to the decreasing of decomposition temperature (Td of hybrid membranes.

  17. Enhancing biocompatibility of some cation selective electrodes using heparin modified bacterial cellulose.

    Science.gov (United States)

    Badr, Ibrahim H A; Abdel-Sattar, R; Keshk, Sherif M A S

    2015-12-10

    Bacterial cellulose (BC) and heparin-modified bacterial cellulose (HBC) were utilized to enhance the biocompatibility of highly thrombogenic PVC-based potassium and calcium membrane electrodes. Three types of membrane electrodes were prepared: (1) conventional PVC electrode (control), (2) PVC-based electrode sandwiched with bacterial cellulose membrane (BC-PVC), and (3) PVC-based electrode sandwiched with heparin-modified bacterial cellulose membrane (HBC-PVC). The potentiometric response characteristics of the modified potassium and calcium membrane electrodes (BC-PVC and HBC-PVC) were compared with those of the control PVC-based potassium and calcium selective electrode, respectively. Response characteristics of the modified membrane electrodes were comparable to the control PVC membrane electrode. The platelet adhesion investigations indicated that (BC) and (HBC) layers are less thrombogenic compared to PVC. Therefore, use of BC or HBC would enable the enhancement of the biocompatibility of PVC-based membrane electrodes for potassium and calcium while practically maintaining the overall electrochemical performance of the PVC sensing film. PMID:26428173

  18. Enhanced enzymatic cellulose degradation by cellobiohydrolases via product removal

    DEFF Research Database (Denmark)

    Ahmadi Gavlighi, Hassan; Meyer, Anne S.; Mikkelsen, Jørn Dalgaard

    2013-01-01

    .8. The optimum in a mixture of the two was 50 °C, pH 4.9. An almost fourfold increase in enzymatic hydrolysis yield was achieved with intermittent product removal of cellobiose with membrane filtration (2 kDa cut-off): The conversion of cotton cellulose after 72 h was ~19 % by weight, whereas the conversion......Product inhibition by cellobiose decreases the rate of enzymatic cellulose degradation. The optimal reaction conditions for two Emericella (Aspergillus) nidulans-derived cellobiohydrolases I and II produced in Pichia pastoris were identified as CBHI: 52 °C, pH 4.5–6.5, and CBHII: 46 °C, pH 4...... achievable by intermittent product removal during cellulose hydrolysis....

  19. Cellulose acetate as solid phase in ELISA for plague

    Directory of Open Access Journals (Sweden)

    Barbosa AD

    2000-01-01

    Full Text Available Antigen from Yersinia pestis was adsorbed on cellulose acetate discs (0.5 cm of diameter which were obtained from dialysis membrane by using a paper punch. ELISA for human plague diagnosis was carried out employing this matrix and was capable to detect amount of 1.3 µg of antigen, 3,200 times diluted positive serum using human anti-IgG conjugate diluted 1:4,000. No relevant antigen lixiviation from the cellulose acetate was observed even after washing the discs 15 times. The discs were impregnated by the coloured products from the ELISA development allowing its use in dot-ELISA. Furthermore, cellulose acetate showed a better performance than the conventional PVC plates.

  20. PVA、PVP和β- CD改性再生纤维素膜的制备及渗透汽化分离己内酰胺水溶液%Preparation of PVA,PVP andβ- CD Modified Regenerated Cellulose Membrane and Pervaporation Separation of Caprolactam- Water Mixtures

    Institute of Scientific and Technical Information of China (English)

    朱天容; 李忠铭; 刘继延; 王亮; 胡思前; 唐开

    2014-01-01

    己内酰胺(CPL)是重要的有机化工原料,对CPL脱水是除杂工艺中最后一步。然而,CPL是热敏性物质,为防止CPL高温分解,重点研究了渗透汽化膜分离技术对CPL脱水。以棉短绒为制膜原料,采用碱溶解方法,通过相转变制备了再生纤维素(RC)膜。研究了铸膜液浓度对膜结构的影响。铸膜液的最佳浓度为4 wt %,RC膜表面平滑、无孔,可作为渗透汽化膜,但纯RC膜的通量较小。因此,选取了聚乙烯醇(PVA)、聚乙烯吡咯烷酮(PVP)和β-环糊精(β-CD)分别对RC膜共混改性,考察了改性膜的溶胀度、接触角和渗透汽化膜分离性能。RC-PVA膜的机械强度、通量和分离因子均优于纯RC膜。β-CD提高了膜的分离因子,对通量影响较小。%Caprolactam(C6H11NO)is one of the most important material in the polymer industry, de⁃hydration is the most important edulcoration technology in the final caprolactam purification. Howev⁃er,caprolactam is heat-sensitive substance, for prevention of degradation under high temperature, the dehydration of caprolactam with pervaporation (PVP) is studied. Cotton as membrane material and is firstly dessloved in the alkaline solution, then the regenerated cellulose(RC)is prepared by phase inversion method. The influence of concentration of casting solution on the membrane struc⁃ture is investigated. The results show that the 4 wt % cellulose concentration is suitable to prepare the PV membrane. But the flux and separation factor of pure RC membrane are not ideal. Therefore, polyvinyl alcohol(PVA),Polyvinyl-Py-rrolidone(PVP)and β-cyclodextrin(β-CD)are selected to modify the RC membrane. The degree of swelling,contact angle and PV performance of the modi⁃fied membranes are tested. RC-PVA has better properties and the strength,the flux and the separa⁃tion factor are improved. With the addition ofβ-CD,the separation factor of membrane is enhanced, and it

  1. Manufacture and study of osmotic metallic membranes

    International Nuclear Information System (INIS)

    The manufacture of metallic membranes, which are semi-permeable to salt water, was investigated. The best results were obtained with nickel which had been deposited 'in situ' on sintered nickel, whose pore spectrum was sharp. The investigation showed that in the case of metallic membranes reverse osmosis is only a filtration. The large quantities of water produced and the low salt rejection rate compared to that with cellulose acetate membranes demonstrated that metallic membranes are better suited to depollution than desalination. (author)

  2. Use of biomimetic forward osmosis membrane for trace organics removal

    DEFF Research Database (Denmark)

    Madsen, Henrik T.; Bajraktari, Niada; Helix Nielsen, Claus;

    2015-01-01

    pollutants in aqueous solution. The performance of this membrane was compared with a standard cellulose acetate forward osmosis membrane. The aquaporin membrane was found to have rejection values above 97% for all three trace organics, which was significantly higher than the cellulose acetate membrane....... This difference is caused by differences in the transport mechanisms. For the cellulose acetate membrane rejection is controlled by steric hindrance, which results in a size dependent rejection of the trace organics, whereas rejection by the aquaporin membrane is controlled by diffusion of the trace organics......The use of forward osmosis for the removal of trace organics from water has recently attracted considerable attention as an alternative to traditional pressure driven membrane filtration. However, the existing forward osmosis membranes have been found to be ineffective at rejecting small neutral...

  3. Preparation of High Quality Indium Tin Oxide Film on a Microbial Cellulose Membrane Using Radio Frequency Magnetron Sputtering%采用磁控溅射法在细菌纤维素膜上制备高性能的铟锡氧化物薄膜

    Institute of Scientific and Technical Information of China (English)

    杨加志; 赵成刚; 刘晓丽; 于俊伟; 孙东平; 唐卫华

    2011-01-01

    Microbial cellulose (MC) membranes produced by Acetobacterxylinumn NUST4.1, were used as flexible substrates for the fabrication of transparent indium tin oxide (ITO) electrodes. Transparent and conductive ITO thin films were deposited on MC membrane at room temperature using radio frequency (RF) magnetron sputtering. The optimum ITO deposition conditions were achieved by examining crystalline structure, surface morphology and optoelectrical characteristics with X-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM), and UV spectroscopy. The sheet resistance of the samples was measured with a four-point probe and the resistivity of the film was calculated. The results reveal that the preferred orientation of the deposited ITO crystals is strongly dependent upon with oxygen content (O2/Ar, volume ratio) in the sputtering chamber. And the ITO crystalline structure directly determines the conductivity of ITO-deposited films. High conductive [sheet resistance -120 Ω·square-1 (Ω·sq-1)] and transparent (above 76%) ITO thin films (240 nm thick) were obtained with a moderate sputtering power (about 60 W) and with an oxygen flow rate of 0.25 ml.min-1(sccm) during the deposition. These results show that the ITO-MC electrodes can find their potential application in optoelectrical devices.

  4. Separation membrane development

    Energy Technology Data Exchange (ETDEWEB)

    Lee, M.W. [Savannah River Technology Center, Aiken, SC (United States)

    1998-08-01

    A ceramic membrane has been developed to separate hydrogen from other gases. The method used is a sol-gel process. A thin layer of dense ceramic material is coated on a coarse ceramic filter substrate. The pore size distribution in the thin layer is controlled by a densification of the coating materials by heat treatment. The membrane has been tested by permeation measurement of the hydrogen and other gases. Selectivity of the membrane has been achieved to separate hydrogen from carbon monoxide. The permeation rate of hydrogen through the ceramic membrane was about 20 times larger than Pd-Ag membrane.

  5. Adsorption of Dissolved Organic Matter to the Inorganic Filter Substrate and Its Implications for 14C Uptake Measurements

    OpenAIRE

    Maske, Helmut; Garcia-Mendoza, Ernesto

    1994-01-01

    Inorganic carbon uptake rates for glass fiber-filtered samples are higher than those for membrane-filtered samples because of adsorption of dissolved organic matter to the filter substrate. Experimentally derived values for adsorption onto filters were as follows (relative units): GF/F filter, 1, quartz filter, 1.1, GF/C filter, 0.6; GN-6 Gelman filter, 0.1; Nuclepore and Poretics filter, 0.0; Anodisc filter, 0.4 to 1.9.

  6. ACCESSIBILITY AND CRYSTALLINITY OF CELLULOSE

    Directory of Open Access Journals (Sweden)

    Michael Ioelovich

    2009-08-01

    Full Text Available The accessibility of cellulose samples having various degrees of crystallinity was studied with respect to molecules of water, lower primary alcohols, and lower organic acids. It was found that small water molecules have full access to non-crystalline domains of cellulose (accessibility coefficient α = 1. Molecules of the lowest polar organic liquids (methanol, ethanol, and formic acid have partial access into the non-crystalline domains (α<1, and with increasing diameter of the organic molecules their accessibility to cellulose structure decreases. Accessibility of cellulose samples to molecules of various substances is a linear function of the coefficient α and the content of non-crystalline domains. The relationship between crystallinity (X and accessibility (A of cellulose to molecules of some liquids has been established as A = α (1-X. The water molecules were found to have greater access to cellulose samples than the molecules of the investigated organic liquids. The obtained results permit use of accessibility data to estimate the crystallinity of cellulose, to examine the structural state of non-crystalline domains, and to predict the reactivity of cellulose samples toward some reagents.

  7. TEMPO-oxidized cellulose nanofibers

    Science.gov (United States)

    Isogai, Akira; Saito, Tsuguyuki; Fukuzumi, Hayaka

    2011-01-01

    Native wood celluloses can be converted to individual nanofibers 3-4 nm wide that are at least several microns in length, i.e. with aspect ratios >100, by TEMPO (2,2,6,6-tetramethylpiperidine-1-oxyl radical)-mediated oxidation and successive mild disintegration in water. Preparation methods and fundamental characteristics of TEMPO-oxidized cellulose nanofibers (TOCN) are reviewed in this paper. Significant amounts of C6 carboxylate groups are selectively formed on each cellulose microfibril surface by TEMPO-mediated oxidation without any changes to the original crystallinity (~74%) or crystal width of wood celluloses. Electrostatic repulsion and/or osmotic effects working between anionically-charged cellulose microfibrils, the ζ-potentials of which are approximately -75 mV in water, cause the formation of completely individualized TOCN dispersed in water by gentle mechanical disintegration treatment of TEMPO-oxidized wood cellulose fibers. Self-standing TOCN films are transparent and flexible, with high tensile strengths of 200-300 MPa and elastic moduli of 6-7 GPa. Moreover, TOCN-coated poly(lactic acid) films have extremely low oxygen permeability. The new cellulose-based nanofibers formed by size reduction process of native cellulose fibers by TEMPO-mediated oxidation have potential application as environmentally friendly and new bio-based nanomaterials in high-tech fields.

  8. Product inhibition of enzymatic hydrolysis of cellulose: are we running the reactions all wrong?

    DEFF Research Database (Denmark)

    Meyer, Anne S.

    2012-01-01

    Enzyme catalyzed deconstruction of cellulose to glucose is an important technology step in lignocellulose-to-ethanol processing as well as in the future biorefinery based production of novel products to replace fossil oil based chemistry. The main goals of the enzymatic biomass saccharification i....... Based on cellulose inhibition kinetics the talk will illustrate the suitability of membrane reactor technology for improving cellulose substrate conversion efficiency.......Enzyme catalyzed deconstruction of cellulose to glucose is an important technology step in lignocellulose-to-ethanol processing as well as in the future biorefinery based production of novel products to replace fossil oil based chemistry. The main goals of the enzymatic biomass saccharification...... include high substrate conversion (maximal yields), maximal enzyme efficiency, maximal volumetric reactor productivity, minimal equipment investment, minimal size, and short reaction time. The classic batch type STR reactions used for enzymatic cellulose hydrolysis prevent these goals to be fulfilled...

  9. Extraction and Characterization of Nano cellulose from Coconut Fiber

    International Nuclear Information System (INIS)

    Coconut husk fibers has been modified by some chemical treatments to extract cellulose nano crystals (CNC), which are alkali treatment, bleaching and acid hydrolysis using concentrated sulphuric acid. The effect of the treatments on the coconut husk fibers has been analysed using Fourier transform infrared (FTIR) and X-Ray diffraction (XRD). Meanwhile, the morphology observation and thermal stability of the fiber have been analysed by scanning electron microscopy (SEM) and thermogravimetric analysis (TGA) respectively. The analyses show that the chemical modification could eliminate some of the lignin and hemicelluloses of the fiber. Nano cellulose extracted from acid hydrolysis has been analysed using transmission electron microscopy (TEM) to define the size of extracted nano cellulose. The cellulose nano crystals from coconut fibre has the average diameter and length in the range 13.7±6.2 nm and 172.3±8.4 nm, respectively. The obtained nano cellulose may have the potential applications in the fields of biomedical, oil adsorption, membrane, pharmaceutical and bio composites. (author)

  10. Effect of dietary cellulose on site of lipid absorption

    International Nuclear Information System (INIS)

    The effect of dietary cellulose on the localization within the small intestine of isotopically labeled triglyceride (TG) and cholesterol (CH) from a test meal was investigated. Feeding a 20% cellulose meal resulted in greater quantities of 14C-TG present in both the contents and mucosa of the distal intestine compared with a fiber-free control meal. In contrast, cellulose had no effect on the localization of CH within either the intestinal contents or the mucosa. Accumulation of TG within the intestine was not due to differences in stomach emptying, as the emptying rate was similar for both TG and CH. Within the bulk phase TG must be hydrolyzed by pancreatic lipase before it is available for cellular uptake at the microvillus membrane, whereas CH requires no hydrolysis. The greater amount of TG, but not of CH, within the intestine suggests that cellulose can interfere with lipase activity in vivo. Consequently, cellulose can delay TG hydrolysis and increase the amount of lipid absorbed in the ileum

  11. 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

  12. Golgi-localized STELLO proteins regulate the assembly and trafficking of cellulose synthase complexes in Arabidopsis.

    Science.gov (United States)

    Zhang, Yi; Nikolovski, Nino; Sorieul, Mathias; Vellosillo, Tamara; McFarlane, Heather E; Dupree, Ray; Kesten, Christopher; Schneider, René; Driemeier, Carlos; Lathe, Rahul; Lampugnani, Edwin; Yu, Xiaolan; Ivakov, Alexander; Doblin, Monika S; Mortimer, Jenny C; Brown, Steven P; Persson, Staffan; Dupree, Paul

    2016-01-01

    As the most abundant biopolymer on Earth, cellulose is a key structural component of the plant cell wall. Cellulose is produced at the plasma membrane by cellulose synthase (CesA) complexes (CSCs), which are assembled in the endomembrane system and trafficked to the plasma membrane. While several proteins that affect CesA activity have been identified, components that regulate CSC assembly and trafficking remain unknown. Here we show that STELLO1 and 2 are Golgi-localized proteins that can interact with CesAs and control cellulose quantity. In the absence of STELLO function, the spatial distribution within the Golgi, secretion and activity of the CSCs are impaired indicating a central role of the STELLO proteins in CSC assembly. Point mutations in the predicted catalytic domains of the STELLO proteins indicate that they are glycosyltransferases facing the Golgi lumen. Hence, we have uncovered proteins that regulate CSC assembly in the plant Golgi apparatus. PMID:27277162

  13. Golgi-localized STELLO proteins regulate the assembly and trafficking of cellulose synthase complexes in Arabidopsis

    Science.gov (United States)

    Zhang, Yi; Nikolovski, Nino; Sorieul, Mathias; Vellosillo, Tamara; McFarlane, Heather E.; Dupree, Ray; Kesten, Christopher; Schneider, René; Driemeier, Carlos; Lathe, Rahul; Lampugnani, Edwin; Yu, Xiaolan; Ivakov, Alexander; Doblin, Monika S.; Mortimer, Jenny C.; Brown, Steven P.; Persson, Staffan; Dupree, Paul

    2016-01-01

    As the most abundant biopolymer on Earth, cellulose is a key structural component of the plant cell wall. Cellulose is produced at the plasma membrane by cellulose synthase (CesA) complexes (CSCs), which are assembled in the endomembrane system and trafficked to the plasma membrane. While several proteins that affect CesA activity have been identified, components that regulate CSC assembly and trafficking remain unknown. Here we show that STELLO1 and 2 are Golgi-localized proteins that can interact with CesAs and control cellulose quantity. In the absence of STELLO function, the spatial distribution within the Golgi, secretion and activity of the CSCs are impaired indicating a central role of the STELLO proteins in CSC assembly. Point mutations in the predicted catalytic domains of the STELLO proteins indicate that they are glycosyltransferases facing the Golgi lumen. Hence, we have uncovered proteins that regulate CSC assembly in the plant Golgi apparatus. PMID:27277162

  14. 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. PMID:26964959

  15. CFD simulation of nanofiber-enhanced air filter media

    OpenAIRE

    Tronville, Paolo Maria

    2015-01-01

    The first step in a CFD analysis of filter media flow is to create a computational domain geometry which imitates the simulated media as closely as is practical. The media in the present study combined a relatively flat web of nanofibers with a cellulosic fiber support media. A CFD grid suited to calculating the flow patterns through the cellulosic media structure would be far too coarse to simulate flow around the nanofiber web elements. This scale difference forces some assumption about the...

  16. Synergy Effect of Nanocrystalline Cellulose for the Biosensing Detection of Glucose

    OpenAIRE

    Chakavak Esmaeili; Mahnaz M Abdi; Mathew, Aji P.; Mehdi Jonoobi; Kristiina Oksman,; Majid Rezayi

    2015-01-01

    Integrating polypyrrole-cellulose nanocrystal-based composites with glucose oxidase (GOx) as a new sensing regime was investigated. Polypyrrole-cellulose nanocrystal (PPy-CNC)-based composite as a novel immobilization membrane with unique physicochemical properties was found to enhance biosensor performance. Field emission scanning electron microscopy (FESEM) images showed that fibers were nanosized and porous, which is appropriate for accommodating enzymes and increasing electron transfer ki...

  17. The Potential of Cellulose Extracted from Acacia mangium as Solid Polymer Electrolyte (SPE)

    International Nuclear Information System (INIS)

    Cellulosic materials derived from Acacia mangium was extracted at atmospheric pressure using peroxyacetate acid delignification method at 95 to 100 degree Celsius for three hours,to remove lignin. In second stage, the cellulose was divided into two parts. Each part was bleached in acidified 4 % hydrogen peroxide solution and in 0.8 % NaOH solution containing 4 % of hydrogen peroxide. Both bleaching procedures were treated at 60 to 70 degree Celsius for 45 minutes, with solution to solid ratio maintained at 20 mg/l. In final stage, bleached cellulose was treated with 17.5 % solution of NaOH at 25 degree Celsius for 15 minutes. From X-Ray Diffraction (XRD) and Fourier Transform Infrared Spectroscopy (FTIR) data's, it is proven that cellulose bleached in either acidic and alkaline media has shown cellulose I structure. However, this structure was transformed to cellulose II when treated with strong alkali solution. The preparation of solid polymer electrolyte (SPE) membrane was obtained by dissolving the cellulosic material in molten 1-butyl-3- methylimidazolium chloride (BMIMCL) in the presence of lithium perchlorate (LiClO4). All SPE membranes obtained exhibit conductivity in the range of 4.49 x 10-5 to 5.7 x 10-5 Scm-1 at 25 degree Celsius. Importantly, it was also observed that the conductivity of the SPE is affected by type of extraction. (author)

  18. A Strategy to Develop Bioactive Nanoarchitecture Cellulose: Sustained Release and Multifarious Applications.

    Science.gov (United States)

    Karuppusamy, Sembanadar; Pratheepkumar, Annamalai; Dhandapani, Perumal; Maruthamuthu, Sundaram; Kulandainathan, Manickam Anbu

    2015-09-01

    Cellulose membranes were engineered to produce hydrophobic surfaces via a simple and soft chemical process to introduce multifunctional properties of an otherwise hydrophilic cellulose surface with polymer-grafted nanosilver to form a core-shell nanostructure. A superhydrophobic domain of the polymer on cellulose was created through the amide bond formation between the anhydride units of the polymer and the aminosiloxane-functionalized cellulose through layer-over-layer formulation. This formulation was confirmed through XPS, XRD, 29Si-NMR, and FTIR studies. Further, SEM and TEM analysis revealed that short linear silver nanowires were uniformly obtained with an average diameter of 60 nm and length of 288 nm, using a mild reducing agent at 60 degrees C, which resulted in a hierarchical cellulose surface. The nanosilver colloids released from the hierarchical cellulose surface were stabilized by the polymer matrix in solution, which led to a decrease in the rate of formation of Ag+ enhancing the material's killing efficacy against microbes. This biodegradable nanocomposite-based cellulose hierarchical surface development has potential for application as superhydrophobic membranes for oil-water separation, antimicrobial activity, and pH-triggered sustained release of colloidal silver for wound healing, which could possibly be applied for use as smart bandages. PMID:26485925

  19. A pyranose dehydrogenase-based biosensor for kinetic analysis of enzymatic hydrolysis of cellulose by cellulases

    DEFF Research Database (Denmark)

    Cruys-Bagger, Nicolaj; Badino, Silke Flindt; Tokin, Radina Naytchova;

    2014-01-01

    A novel electrochemical enzyme biosensor was developed for real-time detection of cellulase activity when acting on their natural insoluble substrate, cellulose. The enzyme biosensor was constructed with pyranose dehydrongease (PDH) from Agaricus meleagris that was immobilized on the surface...... jecorina (HjCel6A) on cellulosic substrates with different morphology (bacterial microcrystalline cellulose (BMCC) and Avicel). The steady-state rate of hydrolysis increased towards a saturation plateau with increasing loads of substrate. The experimental results were rationalized using a steady-state rate....... Biosensors covered with a polycarbonate membrane showed high operational stability of several weeks with daily use....

  20. Mechanism of activation of bacterial cellulose synthase by cyclic-di-GMP

    OpenAIRE

    Morgan, Jacob L.W.; McNamara, Joshua T.; Zimmer, Jochen

    2014-01-01

    The bacterial signaling molecule cyclic-di-GMP stimulates the synthesis of bacterial cellulose, frequently found in biofilms. Bacterial cellulose is synthesized and translocated across the inner membrane by a complex of the cellulose synthase BcsA and BcsB subunits. Here we present crystal structures of the cyclic-di-GMP-activated BcsA–B complex. The structures reveal that cyclic-di-GMP releases an auto-inhibited state of the enzyme by breaking a salt bridge which otherwise tethers a conserve...

  1. Preparation of Electrically Conductive Polymeric Membranes

    Science.gov (United States)

    Encinas, J. C.; Castillo-Ortega, M. M.; Rodríguez, F.; Castaño, V. M.

    2015-10-01

    Cellulose acetate porous membranes, coated with polyaniline, were chemically modified with polyelectrolytes to produce films of varying and controlled porosity and electrical conductivity. The highest electrical conductivity was obtained in membranes prepared with poly(styrene sulfonate) with large pore sizes. The electrical properties as well as scanning electron microscopy (SEM) images are discussed.

  2. 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

  3. 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

  4. Preparation and Characterization of New Nano-cellulose Polysulfone Composite Membrane%新型纳米纤维素聚砜复合膜的制备及表征

    Institute of Scientific and Technical Information of China (English)

    赵恒; 吴桐; 周益同; 张力平

    2013-01-01

    L-S immersion precipitation phase inversion method was used to prepare nanocellulose (NCC)/polysulfone (PSF) composite membrane materials.The influence of NCC contents and concentrations (10%,30%,50%)of isopropanol coagulation bath on the membrane structure was characterized.The pore structure of the composite membrane was observed by scanning electron microscope (SEM).With the isopropanol concentration increased,the finger pores in the composite membrane gradually develop from elongated into stubby and loose.At the same time,it can be found that the concentrations of NCC and isopropanol coagulation bath play a significant role on the mechanical properties,pure water flux,porosity and rejection rate of the composite membrane.%采用L-S浸没沉淀相转化法制备纳米纤维素(NCC)/聚砜(PSF)复合膜材料.考察了NCC添加量及异丙醇凝胶浴浓度(10%、30%、50%,体积分数,下同)对膜结构和性能的影响.通过扫描电子显微镜(SEM)观察了复合膜材料断面和皮层的孔结构,发现随着异丙醇浓度的增加,复合膜中的指状孔由细长贯通、连接紧密逐渐变得短粗、疏松.同时,NCC添加量和异丙醇凝胶浴浓度对复合膜的力学性能、渗透性能、膜孔结构有很大的调控作用.

  5. HEMODIALYSIS MEMBRANES: PAST, PRESENT AND FUTURE TRENDS

    Directory of Open Access Journals (Sweden)

    Gautham A

    2013-06-01

    Full Text Available Renal failure is one of the major health problems faced by many people all over the world. These patients choose either transplantation procedure or undergo hemodialysis. Approximately 28% people suffer from renal failures worldwide, among which a quarter are very critical. Patients who opt for hemodialysis have to undergo it regularly. The membranes used in hemodialysis are very vital. The first ever polymer used asan artificial hemodialysis membrane was collodion, which is a derivative of cellulose- trinitrate. This was the leading element for further research and applications in this field. Later collodion was replaced by cellophane and cuprophane since they had better performance and mechanical stability than the collodion. The major disadvantage of this was their less hemocompatiblity as they were made from unmodified cellulose. Nowadays the modified cellulose membrane comes with high-flux modification and thus very effective in many therapy like the hemodiafiltration and the hemofiltration. The success of hemodialysis is highly dependent on the membrane used.

  6. Cellulose Derivatives for Water Repellent Properties

    Science.gov (United States)

    In this poster presentation, we will discuss the synthesis and structural characterizations of nitro-benzyl cellulose (1), amino-benzyl cellulose (2) and pentafluoro –benzyl cellulose (3). All cellulose derivatives are synthesized by etherification process in lithium chloride/N,N-dimethylacetamide h...

  7. 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...

  8. Cellulose synthase complexes: structure and regulation

    Directory of Open Access Journals (Sweden)

    Lei eLei

    2012-04-01

    Full Text Available This review is to update the most recent progress on characterization of the composition, regulation, and trafficking of cellulose synthase complexes. We will highlight proteins that interact with cellulose synthases, e.g. cellulose synthase-interactive protein 1 (CSI1. The potential regulation mechanisms by which cellulose synthase interact with cortical microtubules in primary cell walls will be discussed.

  9. Pharmaceutical significance of cellulose: A review

    Directory of Open Access Journals (Sweden)

    2008-11-01

    Full Text Available The amalgamation of polymer and pharmaceutical sciences led to the introduction of polymer in the design and development of drug delivery systems. Polymeric delivery systems are mainly intended to achieve controlled or sustained drug delivery. Polysaccharides fabricated into hydrophilic matrices remain popular biomaterials for controlled-release dosage forms and the most abundant naturally occurring biopolymer is cellulose; so hdroxypropylmethyl cellulose, hydroxypropyl cellulose, microcrystalline cellulose and hydroxyethyl cellulose can be used for production of time controlled delivery systems. Additionally microcrystalline cellulose, sodium carboxymethyl cellulose, hydroxypropylmethyl cellulose, hydroxyethyl cellulose as well as hydroxypropyl cellulose are used to coat tablets. Cellulose acetate phthalate and hydroxymethyl cellulose phthalate are also used for enteric coating of tablets. Targeting of drugs to the colon following oral administration has also been accomplished by using polysaccharides such as hdroxypropylmethyl cellulose and hydroxypropyl cellulose in hydrated form; also they act as binders that swell when hydrated by gastric media and delay absorption. This paper assembles the current knowledge on the structure and chemistry of cellulose, and in the development of innovative cellulose esters and ethers for pharmaceuticals.

  10. Radiation degradation of cellulose

    International Nuclear Information System (INIS)

    The application of straw and other cellulose polymers as feedstuff for ruminants is limited by its low digestibility. During recent decades it was attempted to increase the digestibility of straw by several chemical and physical methods. In this work some results of the degradation of gamma and electron treated wheat straw are reported. Complex methods of treatment (e.g. radiation influence and influence of lyes) are taken into consideration. In vitro-experiments with radiation treated straw show that the digestibility can be increased from 20% up to about 80%. A high pressure liquid chromatography method was used to analyze the hydrolysates. The contents of certain species of carbohydrates in the hydrolysates in dependence on the applied dose are given

  11. Mineralization of cellulose in frozen boreal soils

    Science.gov (United States)

    Oquist, Mats G.; Segura, Javier; Sparrman, Tobias; Nilsson, Mats; Schleucher, Jurgen

    2015-04-01

    Soils of high-latitude ecosystems store a large fraction of the global soil carbon. In boreal forests, the microbial mineralization of soil organic matter (SOM) during winter can affect the ecosystems net carbon balance. Recent research has shown that microorganisms in the organic surface layer of boreal forest soil can mineralize and grow on simple, soluble monomeric substrates under frozen conditions. However, any substantial impacts of microbial activity in frozen soils on long-term soil carbon balances ultimately depends on whether soil microorganisms can utilize and grow the more complex, polymeric constituents of SOM. In order to evaluate the potential for soil microorganisms to metabolize carbon polymers at low temperatures, we incubated boreal forest soil samples amended with [13C]-cellulose and studied the microbial catabolic and anabolic utilization of the substrate under frozen and unfrozen conditions (-4 and +4°C). Freezing of the soil markedly reduced microbial utilization of the cellulose. The [13C]-CO2 production rate in the samples at +4°C were 0.52 mg CO2 SOM -1 day-1 while rates in the frozen samples (-4°C) were 0.01 mg CO2 SOM -1 day-1. However, newly synthetized [13C]-enriched cell membrane lipids, PLFAs, were detected in soil samples incubated both above and below freezing, confirming that cellulose can sustain also anabolic activity of the microbial populations under frozen conditions. The reduced metabolic rates induced by freezing indicate constraints on exoenzymatic activity, as well as substrate diffusion rates that we can attribute to reduced liquid water content of the frozen soil. We conclude that the microbial population in boreal forest soil has the capacity to metabolize, and grow, on polymeric substrates at temperatures below zero, which involves maintaining exoenzymatic activity in frozen soils. This capacity manifests the importance of SOM mineralization during the winter season and its importance for the net carbon balance of

  12. Thermophilic degradation of cellulosic biomass

    Science.gov (United States)

    Ng, T.; Zeikus, J. G.

    1982-12-01

    The conversion of cellulosic biomass to chemical feedstocks and fuel by microbial fermentation is an important objective of developing biotechnology. Direct fermentation of cellulosic derivatives to ethanol by thermophilic bacteria offers a promising approach to this goal. Fermentations at elevated temperatures lowers the energy demand for cooling and also facilitates the recovery of volatile products. In addition, thermophilic microorganisms possess enzymes with greater stability than those from mesophilic microorganisms. Three anaerobic thermophilic cocultures that ferment cellulosic substrate mainly to ethanol have been described: Clostridium thermocellum/Clostriidium thermohydrosulfuricum, C. thermocellum/Clostridium thermosaccharolyticum, and C. thermocellum/Thermoanaerobacter ethanolicus sp. nov. The growth characteristics and metabolic features of these cocultures are reviewed.

  13. Synthesis and Characterization of Cellulose-Based Hydrogels to Be Used as Gel Electrolytes

    Directory of Open Access Journals (Sweden)

    Maria Assunta Navarra

    2015-11-01

    Full Text Available Cellulose-based hydrogels, obtained by tuned, low-cost synthetic routes, are proposed as convenient gel electrolyte membranes. Hydrogels have been prepared from different types of cellulose by optimized solubilization and crosslinking steps. The obtained gel membranes have been characterized by infrared spectroscopy, scanning electron microscopy, thermogravimetric analysis, and mechanical tests in order to investigate the crosslinking occurrence and modifications of cellulose resulting from the synthetic process, morphology of the hydrogels, their thermal stability, and viscoelastic-extensional properties, respectively. Hydrogels liquid uptake capability and ionic conductivity, derived from absorption of aqueous electrolytic solutions, have been evaluated, to assess the successful applicability of the proposed membranes as gel electrolytes for electrochemical devices. To this purpose, the redox behavior of electroactive species entrapped into the hydrogels has been investigated by cyclic voltammetry tests, revealing very high reversibility and ion diffusivity.

  14. PRODUCTION OF ANTIBACTERIAL FILTER PAPER FROM WOOD CELLULOSE

    OpenAIRE

    Reza Imani; Mohammad Talaiepour; Joydeep Dutta; Mohammad R. Ghobadinezhad; Amir H. Hemmasi; Mousa M. Nazhad

    2011-01-01

    Paper has a visible market-share in hygiene products either in the form of personal hygiene or as food packaging. The designation “hygiene”, though it suggests cleanliness, does not imply antibacterial properties; rather it can be stated that hygiene products do not initiate microorganism growth. Antibacterial products could restrict propagation of pathogenic bacteria either by holding bacteria or by trapping and neutralizing them. Most research in this field has been conducted using textile ...

  15. Chromophores in lignin-free cellulosic materials belong to three compound classes. Chromophores in cellulosics, XII

    Science.gov (United States)

    The CRI (chromophore release and identification) method isolates well-defined chromophoric substances from different cellulosic matrices, such as highly bleached pulps, cotton linters, bacterial cellulose, viscose or lyocell fibers, and cellulose acetates. The chromophores are present only in extrem...

  16. Experimental Evolution of Trichoderma citrinoviride for Faster Deconstruction of Cellulose.

    Science.gov (United States)

    Lin, Hui; Travisano, Michael; Kazlauskas, Romas J

    2016-01-01

    Engineering faster cellulose deconstruction is difficult because it is a complex, cooperative, multi-enzyme process. Here we use experimental evolution to select for populations of Trichoderma citrinoviride that deconstruct up to five-fold more cellulose. Ten replicate populations of T. citrinoviride were selected for growth on filter paper by serial culture. After 125 periods of growth and transfer to fresh media, the filter paper deconstruction increased an average of 2.5 fold. Two populations were examined in more detail. The activity of the secreted cellulase mixtures increased more than two-fold relative to the ancestor and the largest increase was in the extracellular β-glucosidase activity. qPCR showed at least 16-fold more transcribed RNA for egl4 (endoglucanase IV gene), cbh1 (cellobiohydrolase I gene) and bgl1 (extracellular β-glucosidase I gene) in selected populations as compared to the ancestor, and earlier peak expressions of these genes. Deep sequencing shows that the regulatory strategies used to alter cellulase secretion differ in the two strains. The improvements in cellulose deconstruction come from earlier expression of all cellulases and increased relative amount of β-glucosidase, but with small increases in the total secreted protein and therefore little increase in metabolic cost. PMID:26820897

  17. Insitu Cleanable Alternative HEPA Filter Media

    International Nuclear Information System (INIS)

    Two types of filter media, sintered nickel metal and ceramic monolith membrane, are being investigated as in situ regenerable/cleanable high efficiency particulate air (HEPA) filters. Particle retention testing was conducted on the filters at the Oak Ridge Filter Test Facility to ensure HEPA efficiency, greater than 99.97 percent. During simulant testing, The filters were challenged using non-radioactive simulated high-level waste materials and atmospheric dust; materials that cause filter pluggage in the field. After plugging the filters they were cleaned in situ using an aqueous solution. This innovative approach of the in situ regenerative filtration system may be a significant improvement upon the shortfalls of conventional disposable HEPA filters

  18. Insitu Cleanable Alternative HEPA Filter Media

    Energy Technology Data Exchange (ETDEWEB)

    Adamson, D.J.

    2002-05-14

    Two types of filter media, sintered nickel metal and ceramic monolith membrane, are being investigated as in situ regenerable/cleanable high efficiency particulate air (HEPA) filters. Particle retention testing was conducted on the filters at the Oak Ridge Filter Test Facility to ensure HEPA efficiency, greater than 99.97 percent. During simulant testing, The filters were challenged using non-radioactive simulated high-level waste materials and atmospheric dust; materials that cause filter pluggage in the field. After plugging the filters they were cleaned in situ using an aqueous solution. This innovative approach of the in situ regenerative filtration system may be a significant improvement upon the shortfalls of conventional disposable HEPA filters.

  19. Performance research of filter in radon measurement with balloon method

    International Nuclear Information System (INIS)

    Background: Filter membrane is an important part of the balloon emanometer. The membrane of high filtration efficiency but little self-absorption can not only improve the sampling rate, but also reduce the measurement error effectively. Purpose: The experiment aims to compare the performance of three different filter membrane materials. Methods: Based on the radon and its progeny collecting physical processes on the membrane, we deduced the collection of radon in filters and its decay variation with time. Through the experiment, the filtration efficiency and self-absorption factor of the three different membranes have been tested. Results: When the thickness is almost the same, the filtration efficiency of Polytetrafluoroethylene (PTFE) filter and nylon filter is higher than that of commonly used glass fiber filter and its self-absorption is better than that of glass fiber membrane. The air resistance of PTFE filter is the best. It can effectively improve the performance by increasing thickness of the glass fiber filter membrane. Conclusion: This is not only a good reference for the selection of filter membrane in radon measurement with balloon method, but also applicable to radon-measuring devices with other methods. (authors)

  20. Enzymatic Hydrolysis of Cellulose with Different Crystallinities Studied by Means of SEC-MALLS

    Institute of Scientific and Technical Information of China (English)

    张名佳; 苏荣欣; 齐崴; 杜若愚; 何志敏

    2011-01-01

    The reactions of exo-cellulase (cellobiohydrolase, CBH) and endo-cellulase (endoglucanase, EG) were investigated by analyzing the insoluble residues of microcrystalline cellulose (MCC) and filter paper cellulose (FPC) during enzymatic hydrolysis. Molecular parameters including molecular weight and its distribution, degree of polymerization, and radii of gyration were measured by size exclusion chromatography coupled with multi-angle laser light scattering. No significant change in MCC chains was found during the whole reaction period, indicating that CBH digestion follows a layer-by-layer solubilization manner. This reaction mode might be the major reason for slow enzymatic hydrolysis of cellulose. On the other hand, the degree of polymerization of FPC chains decreases rapidly in the initial reaction, indicating that EG digestion follows a random scission manner, which may create new ends for CBH easily. The slopes of the conformation plots for MCC and FPC increase gradually, indicating stronger chain stiffness of cellulose during hvdrolvsis

  1. Asymmetric Membrane Osmotic Capsules for Terbutaline Sulphate

    OpenAIRE

    Gobade, N. G.; Marina Koland; K H Harish

    2012-01-01

    The aim of the present study was to design an asymmetric membrane capsule, an osmotic pump-based drug delivery system of ethyl cellulose for controlled release of terbutaline sulphate. asymmetric membrane capsules contains pore-forming water soluble additive, sorbitol in different concentrations in the capsule shell membrane, which after coming in contact with water, dissolves, resulting in an in situ formation of a microporous structure. The terbutaline sulphate is a β-adrenoreceptor agonist...

  2. Cellulase and Xylanase Production by Penicillium echinulatum in Submerged Media Containing Cellulose Amended with Sorbitol

    Directory of Open Access Journals (Sweden)

    Carla Eliana Todero Ritter

    2013-01-01

    Full Text Available The present work investigated the use of sorbitol as a soluble carbon source, in association with cellulose, to produce cellulases and xylanases in submerged cultures of Penicillium echinulatum 9A02S1. Because cellulose is an insoluble carbon source, in cellulase production, there are some problems with rheology and oxygen transfer. The submerged fermentations containing media composed of 0, 0.25, 0.5, 0.75, and 1% (w/v sorbitol and cellulose that were added at different times during the cultivation; 0.2% (w/v soy bran; 0.1% (w/v wheat bran; and a solution of salts. The highest filter paper activity (FPA ( IU·mL−1 was obtained on the seventh day in the medium containing 0.5% (w/v sorbitol and 0.5% (w/v cellulose added 24 h after the start of cultivation. However, the CMCases showed an activity peak on the sixth day ( IU·mL−1 in the medium containing 0.75% (w/v sorbitol and 0.75% (w/v cellulose added after 12 h of cultivation. The xylanases showed the highest activity in the medium with 0.75% (w/v sorbitol and 0.25% (w/v cellulose added 36 h after the start of cultivation. This strategy enables the reduction of the cellulose concentration, which in high concentrations can cause rheological and oxygen transfer problems.

  3. Development of carboxymethyl cellulose acrylate for various biomedical applications

    Science.gov (United States)

    Pal, Kunal; Banthia, A. K.; Majumdar, D. K.

    2006-06-01

    The purpose of this work is to prepare a pH-sensitive hydrogel membrane of sodium carboxymethyl cellulose acrylate for drug delivery and other biomedical applications. The hydrogel was made by esterification of sodium carboxymethyl cellulose (SCMC) and acryloyl chloride (ACl). The esterified product was characterized by FTIR spectroscopy and XRD. Swelling, hemocompatibility, water vapor transmission rate, contact angle and diffusional studies were also done. Biocompatibility of the membrane was established by quantification of cell growth of L929 cells and mice splenocytes. The FTIR spectrum of the hydrogel suggested the formation of ester bonds between the hydroxyl groups of sodium carboxymethyl cellulose and the carbonyl group of acryloyl chloride. Water vapor transmission rate, hemocompatibility, contact angle and swelling studies indicated that the hydrogel can be tried as a wound dressing material. The hydrogel showed pH-dependent swelling behavior arising from the acidic pendant group in the polymer network. The permeability of the hydrogel membrane produced, as shown by salicylic acid diffusion, increased in response to an increase in pH of the external medium. The hydrogel membrane was permeable to salicylic acid at pH 7.2 but not at pH 2.0 (0.01N HCl). The effect of changes of pH on the hydrogel's permeability was found to be reversible. The hydrogel membrane was found to be compatible with the L929 mice fibroblast cell line and mice splenocytes. The esterified product of SCMC and ACl swells on increase of pH indicating its possible use in a pH-sensitive drug delivery system and as a wound dressing material.

  4. Development of carboxymethyl cellulose acrylate for various biomedical applications

    Energy Technology Data Exchange (ETDEWEB)

    Pal, Kunal [Materials Science Centre, Indian Institute of Technology, Kharagpur 721302 (India); Banthia, A K [Materials Science Centre, Indian Institute of Technology, Kharagpur 721302 (India); Majumdar, D K [Delhi Institute of Pharmaceutical Sciences and Research, Formerly College of Pharmacy, University of Delhi, Pushp Vihar, Sector III, New Delhi 110017 (India)

    2006-06-15

    The purpose of this work is to prepare a pH-sensitive hydrogel membrane of sodium carboxymethyl cellulose acrylate for drug delivery and other biomedical applications. The hydrogel was made by esterification of sodium carboxymethyl cellulose (SCMC) and acryloyl chloride (ACl). The esterified product was characterized by FTIR spectroscopy and XRD. Swelling, hemocompatibility, water vapor transmission rate, contact angle and diffusional studies were also done. Biocompatibility of the membrane was established by quantification of cell growth of L929 cells and mice splenocytes. The FTIR spectrum of the hydrogel suggested the formation of ester bonds between the hydroxyl groups of sodium carboxymethyl cellulose and the carbonyl group of acryloyl chloride. Water vapor transmission rate, hemocompatibility, contact angle and swelling studies indicated that the hydrogel can be tried as a wound dressing material. The hydrogel showed pH-dependent swelling behavior arising from the acidic pendant group in the polymer network. The permeability of the hydrogel membrane produced, as shown by salicylic acid diffusion, increased in response to an increase in pH of the external medium. The hydrogel membrane was permeable to salicylic acid at pH 7.2 but not at pH 2.0 (0.01N HCl). The effect of changes of pH on the hydrogel's permeability was found to be reversible. The hydrogel membrane was found to be compatible with the L929 mice fibroblast cell line and mice splenocytes. The esterified product of SCMC and ACl swells on increase of pH indicating its possible use in a pH-sensitive drug delivery system and as a wound dressing material.

  5. Development of carboxymethyl cellulose acrylate for various biomedical applications

    International Nuclear Information System (INIS)

    The purpose of this work is to prepare a pH-sensitive hydrogel membrane of sodium carboxymethyl cellulose acrylate for drug delivery and other biomedical applications. The hydrogel was made by esterification of sodium carboxymethyl cellulose (SCMC) and acryloyl chloride (ACl). The esterified product was characterized by FTIR spectroscopy and XRD. Swelling, hemocompatibility, water vapor transmission rate, contact angle and diffusional studies were also done. Biocompatibility of the membrane was established by quantification of cell growth of L929 cells and mice splenocytes. The FTIR spectrum of the hydrogel suggested the formation of ester bonds between the hydroxyl groups of sodium carboxymethyl cellulose and the carbonyl group of acryloyl chloride. Water vapor transmission rate, hemocompatibility, contact angle and swelling studies indicated that the hydrogel can be tried as a wound dressing material. The hydrogel showed pH-dependent swelling behavior arising from the acidic pendant group in the polymer network. The permeability of the hydrogel membrane produced, as shown by salicylic acid diffusion, increased in response to an increase in pH of the external medium. The hydrogel membrane was permeable to salicylic acid at pH 7.2 but not at pH 2.0 (0.01N HCl). The effect of changes of pH on the hydrogel's permeability was found to be reversible. The hydrogel membrane was found to be compatible with the L929 mice fibroblast cell line and mice splenocytes. The esterified product of SCMC and ACl swells on increase of pH indicating its possible use in a pH-sensitive drug delivery system and as a wound dressing material

  6. Opportunity for profitable investments in cellulosic biofuels

    International Nuclear Information System (INIS)

    Research efforts to allow large-scale conversion of cellulose into biofuels are being undertaken in the US and EU. These efforts are designed to increase logistic and conversion efficiencies, enhancing the economic competitiveness of cellulosic biofuels. However, not enough attention has been paid to the future market conditions for cellulosic biofuels, which will determine whether the necessary private investment will be available to allow a cellulosic biofuels industry to emerge. We examine the future market for cellulosic biofuels, differentiating between cellulosic ethanol and 'drop-in' cellulosic biofuels that can be transported with petroleum fuels and have equivalent energy values. We show that emergence of a cellulosic ethanol industry is unlikely without costly government subsidies, in part because of strong competition from conventional ethanol and limits on ethanol blending. If production costs of drop-in cellulosic biofuels fall enough to become competitive, then their expansion will not necessarily cause feedstock prices to rise. As long as local supplies of feedstocks that have no or low-valued alternative uses exist, then expansion will not cause prices to rise significantly. If cellulosic feedstocks come from dedicated biomass crops, then the supply curves will have a steeper slope because of competition for land. - Research highlights: → The likelihood of a significant cellulosic ethanol industry in the US looks dim. → Drop-in biofuels made from cellulosic feedstocks have a more promising future. → The spatial dimension of markets for cellulosic feedstocks will be limited. → Corn ethanol will be a tough competitor for cellulosic ethanol.

  7. Research on SF/PEI self-assembly nano fiber membrane for filtering Cu2+%SF/PEI自组装纳米纤维膜用于Cu2+过滤的研究

    Institute of Scientific and Technical Information of China (English)

    马瑞丽; 何建新; 张弦

    2012-01-01

    采用静电层层自组装技术将丝素(SF)与聚乙烯亚胺(PEI)复合制备的SF/PEI纳米纤维,随着自组装层数的增多,纤维直径变粗,表面变得不规整,且在一定的自组装层数内,复合纳米纤维膜对Cu2+的过滤效率不断增大.杂化Fe后,纤维表面变得更加凹凸不平,但对Cu2+的过滤效果显著改善.这对于制备新型、高效、无二次污染、低治理成本的替代或改进的重金属过滤材料提供了理论意义.%F/PEI composite Nano fiber membrane was made in this experiment by layer-layer electrostatic self-assembly technology, With the increasing in the number in self-assembly layer, the fiber diameter become larger, the surface become irregular, and in certain layer, the adsorption efficiency of Cu2+ increases. After the hybrid Fe, fiber surface become more uneven, but the adsorption efficiency improved significantly. This experiment provides theoretical significance for new, effective, no secondary pollution and low management cost alternative or improved heavy metal filter material.

  8. Comparison of Three Methods of Pour Plate (PP ، Most Probable Number (MPN and Membrane Filter (MF for Detection of Escherichia coli in Well Water Samples in Tehran's Parks in 2010

    Directory of Open Access Journals (Sweden)

    Soltan Dallal, MM

    2010-01-01

    Full Text Available Background and objectives: Water-born diseases are typically causedby pathogens transmitted by orofecal way. Because it is no practical andno economical and also it is time-consuming to find water-bornpathogens in water reservoirs, the laboratory studies are performed on thebasis of indicator microorganism. Escherichia coli is considered as themost important indicator bacterium for water monitoring. The aim of thisstudy was to evaluate the three methods of Pour Plate (PP, MostProbable Number (MPN and Membrane Filter (MF in isolation ofEscherichia coli in well water of Parks.Material and Methods: One hundred and sixty five samples of wellwater, from five geographical zones of north, south, east, west and centerof Tehran, were taken in a sterile condition and sent to microbiologydepartment of health faculty to assess with three methods of PP, MPNand MF. The results were analyzed by chi-square.Results: The results indicate that 90 water samples (54.5% aren’t health.The samples taken from south of Tehran are most contaminant than otherzones. The highest contaminated Samples (54.5% are related tomembrane filtration method in comparison with MPN (34.5% and PP(27.3%.Conclusion: Since the MF method can recognize the contaminantsquickly and effectively, we recommend it more. Based on these results, itis essential to educate children not to drink well water in parks.Keywords: well water contamination, Escherichia coli, Tehran's parks

  9. Reactor design for minimizing product inhibition during enzymatic lignocellulose hydrolysis II. Quantification of inhibition and suitability of membrane reactors

    DEFF Research Database (Denmark)

    Andric, Pavle; Meyer, Anne S.; Jensen, Peter Arendt;

    2010-01-01

    ideal reactor types, i.e. batch, continuous stirred, and plug-flow, is illustrated quantitatively by modeling different extents of cellulose conversion at different reaction conditions. The main operational challenges of membrane reactors for lignocellulose conversion are highlighted. Key membrane...... of the available literature data for glucose removal by membranes and for cellulose enzyme stability in membrane reactors are given. The treatise clearly shows that membrane reactors allowing continuous, complete, glucose removal during enzymatic cellulose hydrolysis, can provide for both higher cellulose...... hydrolysis rates and higher enzyme usage efficiency (kg(product/)kg(enzyme)). Current membrane reactor designs are however not feasible for large scale operations. The report emphasizes that the industrial realization of cellulosic ethanol requires more focus on the operational feasibility within...

  10. Molecular modeling and imaging of initial stages of cellulose fibril assembly: evidence for a disordered intermediate stage.

    Directory of Open Access Journals (Sweden)

    Candace H Haigler

    Full Text Available The remarkable mechanical strength of cellulose reflects the arrangement of multiple β-1,4-linked glucan chains in a para-crystalline fibril. During plant cellulose biosynthesis, a multimeric cellulose synthesis complex (CSC moves within the plane of the plasma membrane as many glucan chains are synthesized from the same end and in close proximity. Many questions remain about the mechanism of cellulose fibril assembly, for example must multiple catalytic subunits within one CSC polymerize cellulose at the same rate? How does the cellulose fibril bend to align horizontally with the cell wall? Here we used mathematical modeling to investigate the interactions between glucan chains immediately after extrusion on the plasma membrane surface. Molecular dynamics simulations on groups of six glucans, each originating from a position approximating its extrusion site, revealed initial formation of an uncrystallized aggregate of chains from which a protofibril arose spontaneously through a ratchet mechanism involving hydrogen bonds and van der Waals interactions between glucose monomers. Consistent with the predictions from the model, freeze-fracture transmission electron microscopy using improved methods revealed a hemispherical accumulation of material at points of origination of apparent cellulose fibrils on the external surface of the plasma membrane where rosette-type CSCs were also observed. Together the data support the possibility that a zone of uncrystallized chains on the plasma membrane surface buffers the predicted variable rates of cellulose polymerization from multiple catalytic subunits within the CSC and acts as a flexible hinge allowing the horizontal alignment of the crystalline cellulose fibrils relative to the cell wall.

  11. Molecular modeling and imaging of initial stages of cellulose fibril assembly: evidence for a disordered intermediate stage.

    Science.gov (United States)

    Haigler, Candace H; Grimson, Mark J; Gervais, Julien; Le Moigne, Nicolas; Höfte, Herman; Monasse, Bernard; Navard, Patrick

    2014-01-01

    The remarkable mechanical strength of cellulose reflects the arrangement of multiple β-1,4-linked glucan chains in a para-crystalline fibril. During plant cellulose biosynthesis, a multimeric cellulose synthesis complex (CSC) moves within the plane of the plasma membrane as many glucan chains are synthesized from the same end and in close proximity. Many questions remain about the mechanism of cellulose fibril assembly, for example must multiple catalytic subunits within one CSC polymerize cellulose at the same rate? How does the cellulose fibril bend to align horizontally with the cell wall? Here we used mathematical modeling to investigate the interactions between glucan chains immediately after extrusion on the plasma membrane surface. Molecular dynamics simulations on groups of six glucans, each originating from a position approximating its extrusion site, revealed initial formation of an uncrystallized aggregate of chains from which a protofibril arose spontaneously through a ratchet mechanism involving hydrogen bonds and van der Waals interactions between glucose monomers. Consistent with the predictions from the model, freeze-fracture transmission electron microscopy using improved methods revealed a hemispherical accumulation of material at points of origination of apparent cellulose fibrils on the external surface of the plasma membrane where rosette-type CSCs were also observed. Together the data support the possibility that a zone of uncrystallized chains on the plasma membrane surface buffers the predicted variable rates of cellulose polymerization from multiple catalytic subunits within the CSC and acts as a flexible hinge allowing the horizontal alignment of the crystalline cellulose fibrils relative to the cell wall. PMID:24722535

  12. Influences of Carboxyl Methyl Cellulose on Performances of Mortar

    Institute of Scientific and Technical Information of China (English)

    WANG Yuli; ZHOU Mingkai; SHAN Junhong; XU Fang; YANG Yuhui

    2007-01-01

    Carboxyl methyl cellulose (CMC) was mixed into mortar to improve the waterretention performance of mortar, the quality of floated coat of aerated concrete became better. The consistency and compression strength of mortar with CMC were studied. The water absorption was studied with the method of filter paper. The micro mechanism was researched with X-ray diffraction and scanning electron microscopy(SEM). The experimental results show the water-holding performance of mortar with CMC is largely improved and it is better when the mixed amount is about 1.5%; the compression strength had a descending trend with the increase of CMC; CMC reacted with calcium hydroxide(CH) into the deposition of calcium carboxyl methyl cellulose.

  13. A thermodynamic investigation of the cellulose allomorphs: Cellulose(am), cellulose Iβ(cr), cellulose II(cr), and cellulose III(cr)

    International Nuclear Information System (INIS)

    Highlights: • Cellulose allomorphs were prepared and carefully characterized. • Measurements by oxygen bomb calorimetry, solution calorimetry, and by PPMS. • Thermodynamic properties for interconversion reactions of the cellulose allomorphs. • Review of the earlier literature with recalculation of property values. • Standard thermodynamic formation properties. - Abstract: The thermochemistry of samples of amorphous cellulose, cellulose I, cellulose II, and cellulose III was studied by using oxygen bomb calorimetry, solution calorimetry in which the solvent was cadoxen (a cadmium ethylenediamine solvent), and with a Physical Property Measurement System (PPMS) in zero magnetic field to measure standard massic heat capacities Cp,w∘ over the temperature range T = (2 to 302) K. The samples used in this study were prepared so as to have different values of crystallinity indexes CI and were characterized by X-ray diffraction, by Karl Fischer moisture determination, and by using gel permeation chromatography to determine the weight average degree of polymerization DPw. NMR measurements on solutions containing the samples dissolved in cadoxen were also performed in an attempt to resolve the issue of the equivalency or non-equivalency of the nuclei in the different forms of cellulose that were dissolved in cadoxen. While large differences in the NMR spectra for the various cellulose samples in cadoxen were not observed, one cannot be absolutely certain that these cellulose samples are chemically equivalent in cadoxen. Equations were derived which allow one to adjust measured property values of cellulose samples having a mass fraction of water wH2O to a reference value of the mass fraction of water wref. The measured thermodynamic properties (standard massic enthalpy of combustion ΔcHw∘, standard massic enthalpy of solution ΔsolHw∘, and Cp,w∘) were used in conjunction with the measured CI values to calculate values of the changes in the standard massic

  14. Cellulose microfibril formation within a coarse grained molecular dynamics

    Science.gov (United States)

    Nili, Abdolmadjid; Shklyaev, Oleg; Crespi, Vincent; Zhao, Zhen; Zhong, Linghao; CLSF Collaboration

    2014-03-01

    Cellulose in biomass is mostly in the form of crystalline microfibrils composed of 18 to 36 parallel chains of polymerized glucose monomers. A single chain is produced by cellular machinery (CesA) located on the preliminary cell wall membrane. Information about the nucleation stage can address important questions about intermediate region between cell wall and the fully formed crystalline microfibrils. Very little is known about the transition from isolated chains to protofibrils up to a full microfibril, in contrast to a large body of studies on both CesA and the final crystalline microfibril. In addition to major experimental challenges in studying this transient regime, the length and time scales of microfibril nucleation are inaccessible to atomistic molecular dynamics. We have developed a novel coarse grained model for cellulose microfibrils which accounts for anisotropic interchain interactions. The model allows us to study nucleation, kinetics, and growth of cellulose chains/protofibrils/microfibrils. This work is supported by the US Department of Energy, Office of Basic Energy Sciences as part of The Center for LignoCellulose Structure and Formation, an Energy Frontier Research Center.

  15. Cellulose Deficiency Is Enhanced on Hyper Accumulation of Sucrose by a H+-Coupled Sucrose Symporter1[OPEN

    Science.gov (United States)

    Yeats, Trevor H.; Sorek, Hagit

    2016-01-01

    In order to understand factors controlling the synthesis and deposition of cellulose, we have studied the Arabidopsis (Arabidopsis thaliana) double mutant shaven3 shaven3-like1 (shv3svl1), which was shown previously to exhibit a marked cellulose deficiency. We discovered that exogenous sucrose (Suc) in growth medium greatly enhances the reduction in hypocotyl elongation and cellulose content of shv3svl1. This effect was specific to Suc and was not observed with other sugars or osmoticum. Live-cell imaging of fluorescently labeled cellulose synthase complexes revealed a slowing of cellulose synthase complexes in shv3svl1 compared with the wild type that is enhanced in a Suc-conditional manner. Solid-state nuclear magnetic resonance confirmed a cellulose deficiency of shv3svl1 but indicated that cellulose crystallinity was unaffected in the mutant. A genetic suppressor screen identified mutants of the plasma membrane Suc/H+ symporter SUC1, indicating that the accumulation of Suc underlies the Suc-dependent enhancement of shv3svl1 phenotypes. While other cellulose-deficient mutants were not specifically sensitive to exogenous Suc, the feronia (fer) receptor kinase mutant partially phenocopied shv3svl1 and exhibited a similar Suc-conditional cellulose defect. We demonstrate that shv3svl1, like fer, exhibits a hyperpolarized plasma membrane H+ gradient that likely underlies the enhanced accumulation of Suc via Suc/H+ symporters. Enhanced intracellular Suc abundance appears to favor the partitioning of carbon to starch rather than cellulose in both mutants. We conclude that SHV3-like proteins may be involved in signaling during cell expansion that coordinates proton pumping and cellulose synthesis. PMID:27013021

  16. Selective permeation of hydrogen gas using cellulose nanofibril film.

    Science.gov (United States)

    Fukuzumi, Hayaka; Fujisawa, Shuji; Saito, Tsuguyuki; Isogai, Akira

    2013-05-13

    Biobased membranes that can selectively permeate hydrogen gas have been developed from aqueous dispersions of 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO)-oxidized cellulose nanofibrils (TOCN) prepared from wood cellulose: TOCN-coated plastic films and self-standing TOCN films. Compared with TOCNs with sodium, lithium, potassium, and cesium carboxylate groups, TOCN with free carboxyl groups (TOCN-COOH) had much high and selective H2 gas permeation performance. Because permeabilities of H2, N2, O2, and CO2 gases through the membranes primarily depended on their kinetic diameters, the gas permeation behavior of the various TOCNs can be explained in terms of a diffusion mechanism. Thus, the selective H2 gas permeability for TOCN-COOH was probably due to a larger average size in free volume holes present between nanofibrils in the layer and film than those of other TOCNs with metal carboxylate groups. The obtained results indicate that TOCN-COOH membranes are applicable as biobased H2 gas separation membranes in fuel cell electric power generation systems. PMID:23594396

  17. Bacterial Cellulose-Hydroxyapatite Nanocomposites for Bone Regeneration

    Directory of Open Access Journals (Sweden)

    S. Saska

    2011-01-01

    Full Text Available The aim of this study was to develop and to evaluate the biological properties of bacterial cellulose-hydroxyapatite (BC-HA nanocomposite membranes for bone regeneration. Nanocomposites were prepared from bacterial cellulose membranes sequentially incubated in solutions of CaCl2 followed by Na2HPO4. BC-HA membranes were evaluated in noncritical bone defects in rat tibiae at 1, 4, and 16 weeks. Thermogravimetric analyses showed that the amount of the mineral phase was 40%–50% of the total weight. Spectroscopy, electronic microscopy/energy dispersive X-ray analyses, and X-ray diffraction showed formation of HA crystals on BC nanofibres. Low crystallinity HA crystals presented Ca/P a molar ratio of 1.5 (calcium-deficient HA, similar to physiological bone. Fourier transformed infrared spectroscopy analysis showed bands assigned to phosphate and carbonate ions. In vivo tests showed no inflammatory reaction after 1 week. After 4 weeks, defects were observed to be completely filled in by new bone tissue. The BC-HA membranes were effective for bone regeneration.

  18. Direct Interfacial Modification of Nanocellulose Films for Thermoresponsive Membrane Templates.

    Science.gov (United States)

    Hakalahti, Minna; Mautner, Andreas; Johansson, Leena-Sisko; Hänninen, Tuomas; Setälä, Harri; Kontturi, Eero; Bismarck, Alexander; Tammelin, Tekla

    2016-02-10

    This letter proposes a strategy to construct tunable films combining the physical characteristics of cellulose nanofibrils and smart polymers for membrane applications. A functional membrane template was obtained by first fabricating a water stable film from cellulose nanofibrils and subsequently surface grafting it with a thermoresponsive polymer, poly(N-isopropylacrylamide). The behavior of the membrane template was dependent on temperature. The increment in slope of relative water permeance around the lower critical solution temperature of poly(N-isopropylacrylamide) increased from 18 to 100% upon polymer attachment. Although the membrane template essentially consisted of wood-based materials, the benefits of smart synthetic polymers were achieved. PMID:26812620

  19. Microfibrillated cellulose: morphology and accessibility

    Energy Technology Data Exchange (ETDEWEB)

    Herrick, F.W.; Casebier, R.L.; Hamilton, J.K.; Sandberg, K.R.

    1983-01-01

    Microfibrillated cellulose (MFC) is prepared by subjecting dilute slurries of cellulose fibers to repeated high-pressure homogenizing action. A highly microfibrillated product will have a gel-like appearance at 2% concentration in water. Such gels have pseudoplastic viscosity properties and are very fluid when stirred at high shear rate. The relative viscosity of 2% MFC dispersions may be used as a measure of the degree of homogenization or microfibrillation of a given wood cellulose pulp. The water retention value of an MFC product can also be used as an indicator for degree of homogenization. Structurally, MFC appears to be a web of interconnected fibrils and microfibrils, the latter having diameters in the range 10-100 nm as observed in scanning and transmission electron micrographs. Chemical studies have revealed that MFC is only moderately degraded, while being greatly expanded in surface area. The accessibility of cellulose in MFC is only moderately degraded, while being greatly expanded in surface area. The accessibility of cellulose in MFC toward chemical reagents is greatly increased. Higher reactivity was demonstrated in dilute cupriethylenediamine solubility, triphenylmethylation, acetylation, periodate oxidation, and mineral acid and cellulase enzyme hydrolysis rates. 16 references, 8 figures, 7 tables.

  20. A dual mechanism of cellulose deficiency in shv3svl1.

    Science.gov (United States)

    Yeats, Trevor H; Somerville, Chris R

    2016-09-01

    SHAVEN3 (SHV3) and its homolog SHAVEN3-like 1 (SVL1) encode glycosylphosphatidylinositol (GPI)-anchored proteins (GAPs) that are involved in cellulose biosynthesis and hypocotyl elongation in Arabidopsis thaliana. In a recent report, we showed that the cellulose and hypocotyl elongation defects of the shv3svl1 double mutant are greatly enhanced by exogenous sucrose in the growth medium. Further investigation of this phenomenon showed that shv3svl1 exhibits a hyperpolarized plasma membrane (PM) proton gradient that is coupled with enhanced accumulation of sucrose via the PM sucrose/proton symporter SUC1. The resulting high intracellular sucrose concentration appears to favor starch synthesis at the expense of cellulose synthesis. Here, we describe our interpretation of these results in terms of 2 potential regulators of cellulose synthesis: intracellular sucrose concentration and a putative signaling pathway that involves SHV3-like proteins. PMID:27494413

  1. The Emerging Role of Protein Phosphorylation as a Critical Regulatory Mechanism Controlling Cellulose Biosynthesis.

    Science.gov (United States)

    Jones, Danielle M; Murray, Christian M; Ketelaar, KassaDee J; Thomas, Joseph J; Villalobos, Jose A; Wallace, Ian S

    2016-01-01

    Plant cell walls are extracellular matrices that surround plant cells and critically influence basic cellular processes, such as cell division and expansion. Cellulose is a major constituent of plant cell walls, and this paracrystalline polysaccharide is synthesized at the plasma membrane by a large protein complex known as the cellulose synthase complex (CSC). Recent efforts have identified numerous protein components of the CSC, but relatively little is known about regulation of cellulose biosynthesis. Numerous phosphoproteomic surveys have identified phosphorylation events in CSC associated proteins, suggesting that protein phosphorylation may represent an important regulatory control of CSC activity. In this review, we discuss the composition and dynamics of the CSC in vivo, the catalog of CSC phosphorylation sites that have been identified, the function of experimentally examined phosphorylation events, and potential kinases responsible for these phosphorylation events. Additionally, we discuss future directions in cellulose synthase kinase identification and functional analyses of CSC phosphorylation sites. PMID:27252710

  2. The Emerging Role of Protein Phosphorylation as a Critical Regulatory Mechanism Controlling Cellulose Biosynthesis

    Science.gov (United States)

    Jones, Danielle M.; Murray, Christian M.; Ketelaar, KassaDee J.; Thomas, Joseph J.; Villalobos, Jose A.; Wallace, Ian S.

    2016-01-01

    Plant cell walls are extracellular matrices that surround plant cells and critically influence basic cellular processes, such as cell division and expansion. Cellulose is a major constituent of plant cell walls, and this paracrystalline polysaccharide is synthesized at the plasma membrane by a large protein complex known as the cellulose synthase complex (CSC). Recent efforts have identified numerous protein components of the CSC, but relatively little is known about regulation of cellulose biosynthesis. Numerous phosphoproteomic surveys have identified phosphorylation events in CSC associated proteins, suggesting that protein phosphorylation may represent an important regulatory control of CSC activity. In this review, we discuss the composition and dynamics of the CSC in vivo, the catalog of CSC phosphorylation sites that have been identified, the function of experimentally examined phosphorylation events, and potential kinases responsible for these phosphorylation events. Additionally, we discuss future directions in cellulose synthase kinase identification and functional analyses of CSC phosphorylation sites. PMID:27252710

  3. Synchrotron SAXS and WAXD Studies of Cellulose Nascent Crystals: Experiment and Structure Analysis

    Science.gov (United States)

    Su, Ying; Burger, Christian; Hsiao, Benjamin S.; Chu, Benjamin

    2012-02-01

    Cellulose nascent crystals extracted from biomass (wood pulp, jute and cotton)by combined chemical and mechanical treatments are low cost, environmentally friendly and high performance materials to form the barrier layer in ultrafiltration membranes. This research project is aimed at using the synchrotron X-ray scattering methods to characterize the nascent crystalline nanofibers in different formats. The SAXS (Small Angle X-ray Scattering) data of cellulose nanofiber suspensions was analyzed and the polydisperse ribbon model with rectangular cross section fit the data well. The 2D and 3D simulations of WAXD (Wide Angle X-ray Diffraction) pattern of jute cellulose fibers solved the contents ratio of cellulose I-alpha and I-beta and Hermans' orientation parameter P2.

  4. Asymmetric membrane osmotic capsules for terbutaline sulphate

    Directory of Open Access Journals (Sweden)

    N G Gobade

    2012-01-01

    Full Text Available The aim of the present study was to design an asymmetric membrane capsule, an osmotic pump-based drug delivery system of ethyl cellulose for controlled release of terbutaline sulphate. asymmetric membrane capsules contains pore-forming water soluble additive, sorbitol in different concentrations in the capsule shell membrane, which after coming in contact with water, dissolves, resulting in an in situ formation of a microporous structure. The terbutaline sulphate is a β-adrenoreceptor agonist widely used in the treatment of asthma. The oral dosage regimen of terbutaline sulphate is 5 mg twice or thrice daily, the plasma half-life is approximate 3-4 h and it produces GI irritation with extensive first pass metabolism. Hence, terbutaline sulphate was chosen as a model drug with an aim to develop controlled release system. Different formulations of ethyl cellulose were prepared by phase inversion technique using different concentrations of sorbitol as pore forming agent. It was found that the thickness of the prepared asymmetric membrane capsules was increased with increase in concentration of ethyl cellulose and pore forming agent, i.e. sorbitol. The dye release study in water and 10% sodium chloride solution indicates that, the asymmetric membrane capsules follow osmotic principle to release content. The pores formed due to sorbitol were confirmed by microscopic observation of transverse section of capsule membrane. Data of in vitro release study of terbutaline sulphate from asymmetric membrane capsules indicated that, the capsules prepared with 10% and 12.5% of ethyl cellulose and 25% of sorbitol released as much as 97.44% and 76.27% in 12 h, respectively with zero order release rate. Hence asymmetric membrane capsule of 10% ethyl cellulose and 25% of sorbitol is considered as optimum for controlled oral delivery of terbutaline sulphate.

  5. Asymmetric membrane osmotic capsules for terbutaline sulphate.

    Science.gov (United States)

    Gobade, N G; Koland, Marina; Harish, K H

    2012-01-01

    The aim of the present study was to design an asymmetric membrane capsule, an osmotic pump-based drug delivery system of ethyl cellulose for controlled release of terbutaline sulphate. asymmetric membrane capsules contains pore-forming water soluble additive, sorbitol in different concentrations in the capsule shell membrane, which after coming in contact with water, dissolves, resulting in an in situ formation of a microporous structure. The terbutaline sulphate is a β-adrenoreceptor agonist widely used in the treatment of asthma. The oral dosage regimen of terbutaline sulphate is 5 mg twice or thrice daily, the plasma half-life is approximate 3-4 h and it produces GI irritation with extensive first pass metabolism. Hence, terbutaline sulphate was chosen as a model drug with an aim to develop controlled release system. Different formulations of ethyl cellulose were prepared by phase inversion technique using different concentrations of sorbitol as pore forming agent. It was found that the thickness of the prepared asymmetric membrane capsules was increased with increase in concentration of ethyl cellulose and pore forming agent, i.e. sorbitol. The dye release study in water and 10% sodium chloride solution indicates that, the asymmetric membrane capsules follow osmotic principle to release content. The pores formed due to sorbitol were confirmed by microscopic observation of transverse section of capsule membrane. Data of in vitro release study of terbutaline sulphate from asymmetric membrane capsules indicated that, the capsules prepared with 10% and 12.5% of ethyl cellulose and 25% of sorbitol released as much as 97.44% and 76.27% in 12 h, respectively with zero order release rate. Hence asymmetric membrane capsule of 10% ethyl cellulose and 25% of sorbitol is considered as optimum for controlled oral delivery of terbutaline sulphate. PMID:23204625

  6. Experimental study of cake formation on heat treated and membrane coated needle felts in a pilot scale pulse jet bag filter using optical in-situ cake height measurement

    OpenAIRE

    Saleem, Mahmood; Khan, Rafi Ullah; Tahir, M. Suleman; Krammer, Gernot

    2011-01-01

    Pulse-jet bag filters are frequently employed for particle removal from off gases. Separated solids form a layer on the permeable filter media called filter cake. The cake is responsible for increasing pressure drop. Therefore, the cake has to be detached at a predefined upper pressure drop limit or at predefined time intervals. Thus the process is intrinsically semi-continuous. The cake formation and cake detachment are interdependent and may influence the performance of the filter. Therefor...

  7. In Situ Cleanable Alternative HEPA Filter Media

    International Nuclear Information System (INIS)

    The Westinghouse Savannah River Company, located at the Savannah River Site in Aiken, South Carolina, is currently testing two types of filter media for possible deployment as in situ regenerable/cleanable High Efficiency Particulate Air (HEPA) filters. The filters are being investigated to replace conventional, disposable, glass-fiber, HEPA filters that require frequent removal, replacement, and disposal. This is not only costly and subjects site personnel to radiation exposure, but adds to the ever-growing waste disposal problem. The types of filter media being tested, as part of a National Energy Technology Laboratory procurement, are sintered nickel metal and ceramic monolith membrane. These media were subjected to a hostile environment to simulate conditions that challenge the high-level waste tank ventilation systems. The environment promoted rapid filter plugging to maximize the number of filter loading/cleaning cycles that would occur in a specified period of time. The filters were challenged using nonradioactive simulated high-level waste materials and atmospheric dust; materials that cause filter pluggage in the field. The filters are cleaned in situ using an aqueous solution. The study found that both filter media were insensitive to high humidity or moisture conditions and were easily cleaned in situ. The filters regenerated to approximately clean filter status even after numerous plugging and in situ cleaning cycles. Air Techniques International is conducting particle retention testing on the filter media at the Oak Ridge Filter Test Facility. The filters are challenged using 0.3-mm di-octyl phthalate particles. Both the ceramic and sintered media have a particle retention efficiency > 99.97%. The sintered metal and ceramic filters not only can be cleaned in situ, but also hold great potential as a long life alternative to conventional HEPA filters. The Defense Nuclear Facility Safety Board Technical Report, ''HEPA Filters Used in the Department of

  8. In Situ Cleanable Alternative HEPA Filter Media

    Energy Technology Data Exchange (ETDEWEB)

    Adamson, D. J.; Terry, M. T.

    2002-02-28

    The Westinghouse Savannah River Company, located at the Savannah River Site in Aiken, South Carolina, is currently testing two types of filter media for possible deployment as in situ regenerable/cleanable High Efficiency Particulate Air (HEPA) filters. The filters are being investigated to replace conventional, disposable, glass-fiber, HEPA filters that require frequent removal, replacement, and disposal. This is not only costly and subjects site personnel to radiation exposure, but adds to the ever-growing waste disposal problem. The types of filter media being tested, as part of a National Energy Technology Laboratory procurement, are sintered nickel metal and ceramic monolith membrane. These media were subjected to a hostile environment to simulate conditions that challenge the high-level waste tank ventilation systems. The environment promoted rapid filter plugging to maximize the number of filter loading/cleaning cycles that would occur in a specified period of time. The filters were challenged using nonradioactive simulated high-level waste materials and atmospheric dust; materials that cause filter pluggage in the field. The filters are cleaned in situ using an aqueous solution. The study found that both filter media were insensitive to high humidity or moisture conditions and were easily cleaned in situ. The filters regenerated to approximately clean filter status even after numerous plugging and in situ cleaning cycles. Air Techniques International is conducting particle retention testing on the filter media at the Oak Ridge Filter Test Facility. The filters are challenged using 0.3-mm di-octyl phthalate particles. Both the ceramic and sintered media have a particle retention efficiency > 99.97%. The sintered metal and ceramic filters not only can be cleaned in situ, but also hold great potential as a long life alternative to conventional HEPA filters. The Defense Nuclear Facility Safety Board Technical Report, ''HEPA Filters Used in the

  9. Generalised Filtering

    Directory of Open Access Journals (Sweden)

    Karl Friston

    2010-01-01

    Full Text Available We describe a Bayesian filtering scheme for nonlinear state-space models in continuous time. This scheme is called Generalised Filtering and furnishes posterior (conditional densities on hidden states and unknown parameters generating observed data. Crucially, the scheme operates online, assimilating data to optimize the conditional density on time-varying states and time-invariant parameters. In contrast to Kalman and Particle smoothing, Generalised Filtering does not require a backwards pass. In contrast to variational schemes, it does not assume conditional independence between the states and parameters. Generalised Filtering optimises the conditional density with respect to a free-energy bound on the model's log-evidence. This optimisation uses the generalised motion of hidden states and parameters, under the prior assumption that the motion of the parameters is small. We describe the scheme, present comparative evaluations with a fixed-form variational version, and conclude with an illustrative application to a nonlinear state-space model of brain imaging time-series.

  10. Microbial Cellulose Assembly in Microgravity

    Science.gov (United States)

    Brown, R. Malcolm, Jr.

    1998-01-01

    Based on evidence indicating a possible correlation between hypo-gravity conditions and alteration of cellulose production by the gram negative bacterium, Acetobacter xylinum, a ground-based study for a possible long term Space Shuttle flight has been conducted. The proposed experiment for A. xylinum aboard the Shuttle is the BRIC (Biological Research in a Canister), a metal container containing spaces for nine Petri plates. Using a common experimental design, the cellulose production capability as well as the survivability of the A. xylinum strains NQ5 and AY201 have been described. It should now be possible to use the BRIC for the first long term microgravity experiments involving the biosynthesis of cellulose.

  11. Effect of membrane polymeric materials on relationship between surface pore size and membrane fouling in membrane bioreactors

    Science.gov (United States)

    Miyoshi, Taro; Yuasa, Kotaku; Ishigami, Toru; Rajabzadeh, Saeid; Kamio, Eiji; Ohmukai, Yoshikage; Saeki, Daisuke; Ni, Jinren; Matsuyama, Hideto

    2015-03-01

    We investigated the effect of different membrane polymeric materials on the relationship between membrane pore size and development of membrane fouling in a membrane bioreactor (MBR). Membranes with different pore sizes were prepared using three different polymeric materials, cellulose acetate butyrate (CAB), polyvinyl butyral (PVB), and polyvinylidene fluoride (PVDF), and the development of membrane fouling in each membrane was evaluated by batch filtration tests using a mixed liquor suspension obtained from a laboratory-scale MBR. The results revealed that the optimal membrane pore size to mitigate membrane fouling differed depending on membrane polymeric material. For PVDF membranes, the degree of membrane fouling decreased as membrane pore size increased. In contrast, CAB membranes with smaller pores had less fouling propensity than those with larger ones. Such difference can be attributed to the difference in major membrane foulants in each membrane; in PVDF, they were small colloids or dissolved organics in which proteins are abundant, and in CAB, microbial flocs. The results obtained in this study strongly suggested that optimum operating conditions of MBRs differ depending on the characteristics of the used membrane.

  12. ADVANCED HOT GAS FILTER DEVELOPMENT

    Energy Technology Data Exchange (ETDEWEB)

    E.S. Connolly; G.D. Forsythe

    2000-09-30

    DuPont Lanxide Composites, Inc. undertook a sixty-month program, under DOE Contract DEAC21-94MC31214, in order to develop hot gas candle filters from a patented material technology know as PRD-66. The goal of this program was to extend the development of this material as a filter element and fully assess the capability of this technology to meet the needs of Pressurized Fluidized Bed Combustion (PFBC) and Integrated Gasification Combined Cycle (IGCC) power generation systems at commercial scale. The principal objective of Task 3 was to build on the initial PRD-66 filter development, optimize its structure, and evaluate basic material properties relevant to the hot gas filter application. Initially, this consisted of an evaluation of an advanced filament-wound core structure that had been designed to produce an effective bulk filter underneath the barrier filter formed by the outer membrane. The basic material properties to be evaluated (as established by the DOE/METC materials working group) would include mechanical, thermal, and fracture toughness parameters for both new and used material, for the purpose of building a material database consistent with what is being done for the alternative candle filter systems. Task 3 was later expanded to include analysis of PRD-66 candle filters, which had been exposed to actual PFBC conditions, development of an improved membrane, and installation of equipment necessary for the processing of a modified composition. Task 4 would address essential technical issues involving the scale-up of PRD-66 candle filter manufacturing from prototype production to commercial scale manufacturing. The focus would be on capacity (as it affects the ability to deliver commercial order quantities), process specification (as it affects yields, quality, and costs), and manufacturing systems (e.g. QA/QC, materials handling, parts flow, and cost data acquisition). Any filters fabricated during this task would be used for product qualification tests

  13. All natural cellulose acetate-Lemongrass essential oil antimicrobial nanocapsules.

    Science.gov (United States)

    Liakos, Ioannis L; D'autilia, Francesca; Garzoni, Alice; Bonferoni, Cristina; Scarpellini, Alice; Brunetti, Virgilio; Carzino, Riccardo; Bianchini, Paolo; Pompa, Pier Paolo; Athanassiou, Athanassia

    2016-08-30

    Nanocapsules and nanoparticles play an essential role in the delivery of pharmaceutical agents in modern era, since they can be delivered in specific tissues and cells. Natural polymers, such as cellulose acetate, are becoming very important due to their availability, biocompatibility, absence of toxicity and biodegradability. In parallel, essential oils are having continuous growth in biomedical applications due to the inherent active compounds that they contain. A characteristic example is lemongrass oil that has exceptional antimicrobial properties. In this work, nanocapsules of cellulose acetate with lemongrass oil were developed with the solvent/anti-solvent method with resulting diameter tailored between 95 and 185nm. Various physico-chemical and surface analysis techniques were employed to investigate the formation of the nanocapsules. These all-natural nanocapsules found to well bioadhere to mucous membranes and to have very good antimicrobial properties at little concentrations against Escherichia coli and Staphylococcus aureus. PMID:26827919

  14. Method of preventing filter contamination

    International Nuclear Information System (INIS)

    Since slight amounts of radioactive corrosion products and soluble ions are contained in condensates produced from a nuclear reactor, they are cleaned-up in a filtration desalter, desalter, etc. before returning to the reactor. Hollow fibrous membrane filters are disposed instead of the filtration desalter for eliminating only the solid contents. When polymeric material such as the hollow fibrous membrance filters are put into contact with purified water of low conductivity, electrostatic charges are accumulated at the interface between them. If the membranes have negative static charges, Fe ions are attracted to increase the Fe ion concentration at the membrane boundary. If they are oxidized with oxygen dissolved in water, ferric hydroxide of low solubility is formed as precipitates. Then, oxidizer, in particular, hydrogen peroxide is added depending on the Fe ion concentration in flowing water entering the filters, to prevent the deposition of the Fe ions. This can prevent clogging in the filters and increase in the differential pressure due to the clogging. (T.M.)

  15. Synthesis of flexible magnetic nanohybrid based on bacterial cellulose under ultrasonic irradiation

    International Nuclear Information System (INIS)

    Flexible magnetic membrane based on bacterial cellulose (BC) was successfully prepared by in-situ synthesis of the Fe3O4 nanoparticles under different conditions and its properties were characterized. The results demonstrated that the Fe3O4 nanoparticles coated with PEG were well homogeneously dispersed in the BC matrix under ultrasonic irradiation with the saturation magnetization of 40.58 emu/g. Besides that, the membranes exhibited the striking flexibility and mechanical properties. This study provided a green and facile method to inhibit magnetic nanoparticle aggregation without compromising the mechanical properties of the nanocomposites. Magnetically responsive BC membrane would have potential applications in electronic actuators, information storage, electromagnetic shielding coating and anti-counterfeit. - Highlights: ► Flexible magnetic film is prepared by in situ synthesis on bacterial cellulose. ► Ultrasound and PEG are used together to inhibit the nanoparticle aggregation. ► The magnetic membrane demonstrates the great superparamagnetic behavior

  16. PROPERTIES OF BACTERIAL CELLULOSE AND ITS INFLUENCE ON THE PHYSICAL PROPERTIES OF PAPER

    Directory of Open Access Journals (Sweden)

    Wen-Hua Gao

    2011-02-01

    Full Text Available Bacterial cellulose is a promising source of biodegradable polymers having high purity. The time required to disperse bacterial cellulose wet membranes was studied, along with evaluation by infrared spectroscopy and thermal analysis of the dispersed bacterial fiber and tests of the physical properties of the sheet. The results showed that bacterial cellulose wet membrane can be dispersed well, forming fibers when the dispersing time was 3 minutes at a suitable concentration. FT-IR results showed that the composition of bacterial fiber is similar to that of bleached softwood fibers. Thus, the morphology, thermal performance, and the length of bacterial fibers are significantly different. The sheets’ physical properties show that with the increasing dosage of bacterial fibers (relative to softwood fiber, the properties of tensile index, tear index, burst index, and stiffness greatly improve, while the porosity and the relative water absorption decrease.

  17. Chemical modification of cellulose for electrospinning applications

    OpenAIRE

    Martín Ferrer, Elena

    2013-01-01

    The aim of the thesis is to develop technology for producing cellulose fatty acid esters that later will be used to produce fibrous materials by means of electrospinning. Main material of the study is cellulose-stearate which is a polymer synthesised by reaction between stearoyl chloride and cellulose. The experimental part consists of synthesis of it by chemical modification of cellulose using ionic liquid as a reaction media. In addition, ionic liquid is also synthesised from the beginning....

  18. Biocompatibility of Bacterial Cellulose Based Biomaterials

    OpenAIRE

    Omar P. Troncoso; Solene Commeaux; Torres, Fernando G.

    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...

  19. A Molecular Description of Cellulose Biosynthesis

    OpenAIRE

    McNamara, Joshua T.; Morgan, Jacob L.W.; Zimmer, Jochen

    2015-01-01

    Cellulose is the most abundant biopolymer on Earth, and certain organisms from bacteria to plants and animals synthesize cellulose as an extracellular polymer for various biological functions. Humans have used cellulose for millennia as a material and an energy source, and the advent of a lignocellulosic fuel industry will elevate it to the primary carbon source for the burgeoning renewable energy sector. Despite the biological and societal importance of cellulose, the molecular mechanism by ...

  20. 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.