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Sample records for macroporous cellulose beads

  1. ADSORPTION AND RELEASING PROPERTIES OF BEAD CELLULOSE

    Institute of Scientific and Technical Information of China (English)

    A. Morales; E. Bordallo; V. Leon; J. Rieumont

    2004-01-01

    The adsorption of some dyes on samples of bead cellulose obtained in the Unit of Research-Production "Cuba 9"was studied. Methylene blue, alizarin red and congo red fitted the adsorption isotherm of Langmuir. Adsorption kinetics at pH = 6 was linear with the square root of time indicating the diffusion is the controlling step. At pH = 12 a non-Fickian trend was observed and adsorption was higher for the first two dyes. Experiments carried out to release the methylene blue occluded in the cellulose beads gave a kinetic behavior of zero order. The study of cytochrome C adsorption was included to test a proteinic material. Crosslinking of bead cellulose was performed with epichlorohydrin decreasing its adsorption capacity in acidic or alkaline solution.

  2. Silica-supported Macroporous Chitosan Bead for Affinity Purification of Trypsin Inhibitor

    Institute of Scientific and Technical Information of China (English)

    Feng Na XI; Jian Min WU; Ming Ming LUAN

    2005-01-01

    Macroporous cross-linking chitosan layer coated on silica gel (CTS-SiO2) was prepared by phase inversion and polyethylene glycol (PEG) molecular imprinting methods. Formation of macroporous surface was investigated by scanning electron microscopy (SEM) and BET analysis.The prepared bead was activated by reacting with 1,2-ethylene diglycidyl ether for introducing epoxy groups, and trypsin could be efficiently immobilized on the bead as a biospecific ligand.The bead bearing trypsin was employed to purify trypsin inhibitor (TIs) from egg white as affinity adsorbent.

  3. Double Emulsion Droplets as Microreactors for Synthesis of Magnetic Macroporous Polymer Beads

    Institute of Scientific and Technical Information of China (English)

    Wei-cai Wang; Chao Peng; Kai Shi; Yan-xiong Pan; Hai-shan Zhang; Xiang-ling Ji

    2014-01-01

    An easy method is presented to fabricate monodisperse magnetic macroporous polymer beads (MMPBs).Waterin-oil high intemal phase emulsion (HIPE) is prepared by emulsifying aqueous iron ions solution in an oil phase containing monomers.The HIPE is introduced into a simple microfluidic device to fabricate monodisperse (water-in-oil)-in-water double emulsion droplets.The droplets serve as microreactors to synthesize Fe3O4 nanoparticles and are on-line polymerized to form MMPBs.The prepared MMPBs display uniform size,interconnected porous structure,superparamagnetic behavior and uniform distribution of Fe3O4 in polymer matrix.The MMPBs are characterized by scanning electron microscopy (SEM),Fourier transform infrared spectroscopy (FTIR),X-ray diffraction (XRD),transmission electron microscopy (TEM),vibrating sample magnetometry (VSM).We believe that this method is a universal technique in preparing macroporous nanocomposite beads.

  4. Structure and superparamagnetic behaviour of magnetite nanoparticles in cellulose beads

    Energy Technology Data Exchange (ETDEWEB)

    Correa, Jose R., E-mail: correa@fq.uh.cu [Department of General Chemistry, Faculty of Chemistry, University of Havana, Zapata and G, Havana City 10400 (Cuba); Bordallo, Eduardo [Sugar Cane-Cellulose Research Center, Cuba-9, Quivican (Cuba); Canetti, Dora [Department of Inorganic Chemistry, Faculty of Chemistry, University of Havana, Zapata and G, Havana City 10400 (Cuba); Leon, Vivian [Sugar Cane-Cellulose Research Center, Cuba-9, Quivican (Cuba); Otero-Diaz, Luis C. [Department of Inorganic Chemistry-1, Complutense University of Madrid, Madrid 28040 (Spain); Electron Microscopy Center, Complutense University of Madrid, Madrid 28040 (Spain); Negro, Carlos [Chemical Engineering Department, Complutense University of Madrid, Madrid 28040 (Spain); Gomez, Adrian [Electron Microscopy Center, Complutense University of Madrid, Madrid 28040 (Spain); Saez-Puche, Regino [Department of Inorganic Chemistry-1, Complutense University of Madrid, Madrid 28040 (Spain)

    2010-08-15

    Superparamagnetic magnetite nanoparticles were obtained starting from a mixture of iron(II) and iron(III) solutions in a preset total iron concentration from 0.04 to 0.8 mol l{sup -1} with ammonia at 25 and 70 {sup o}C. The regeneration of cellulose from viscose produces micrometrical spherical cellulose beads in which synthetic magnetite were embedded. The characterization of cellulose-magnetite beads by X-ray diffraction, Scanning and Transmission Electron Microscopy and magnetic measurement is reported. X-ray diffraction patterns indicate that the higher is the total iron concentration and temperature the higher is the crystal size of the magnetite obtained. Transmission Electron Microscopy studies of cellulose-magnetite beads revealed the distribution of magnetite nanoparticles inside pores of hundred nanometers. Magnetite as well as the cellulose-magnetite composites exhibit superparamagnetic characteristics. Field cooling and zero field cooling magnetic susceptibility measurements confirm the superparamagnetic behaviour and the blocking temperature for the magnetite with a mean size of 12.5 nm, which is 200 K.

  5. Ionic liquid-regenerated macroporous cellulose monolith: Fabrication, characterization and its protein chromatography.

    Science.gov (United States)

    Du, Kaifeng

    2017-04-21

    Macroporous cellulose monolith as chromatographic support was successfully fabricated from an ionic liquid dissolved cellulose solution by an emulsification method and followed by the cross-linking reaction and DEAE modification. With the physical characterization, the cellulose monolith featured by both the interconnected macropores in range of 0.5-2.5μm and the diffusion pores centered at about 10nm. Given the bimodal pore system, the monolith possessed the specific surface area of 36.4m(2)g(-1) and the column permeability of about 7.45×10(-14)m(2). After the DEAE modification, the anion cellulose monolith was evaluated for its chromatography performances. It demonstrated that the static and dynamic adsorption capacity of BSA reached about 66.7mgmL(-1) and 43.9mgmL(-1) at 10% breakthrough point, respectively. The results were comparable to other chromatographic adsorbent. In addition, the proteins mixture with different pI was well separated at high flow velocity (611.0cmh(-1)) and high protein recovery (over 97%), proving the macroporous cellulose monolith had excellent separation performance. In this way, the prepared cellulose monolith with bimodal pores system is expected for the potential application in high-speed chromatography. Copyright © 2017 Elsevier B.V. All rights reserved.

  6. Entrapment of cross-linked cellulase colloids in alginate beads for hydrolysis of cellulose.

    Science.gov (United States)

    Nguyen, Le Truc; Lau, Yun Song; Yang, Kun-Lin

    2016-09-01

    Entrapment of enzymes in calcium alginate beads is a popular enzyme immobilization method. However, leaching of immobilized enzymes from the alginate beads is a common problem because enzyme molecules are much smaller than the pore size of alginate beads (∼200nm). To address this issue, we employ a millifluidic reactor to prepare cross-linked cellulase aggregate (XCA) colloids with a uniform size (∼300nm). Subsequently, these colloids are immobilized in calcium alginate beads as biocatalysts to hydrolyze cellulose substrates. By using fluorescent microscopy, we conclude that the immobilized XCA colloids distribute uniformly inside the beads and do not leach out from the beads after long-term incubation. Meanwhile, the pore size of the alginate beads is big enough for the cellulose substrates and fibers to diffuse into the beads for hydrolysis. For example, palm oil fiber and microcrystalline cellulose can be hydrolyzed within 48h and release reducing sugar concentrations up to 2.48±0.08g/l and 4.99±0.09g/l, respectively. Moreover, after 10 cycles of hydrolysis, 96.4% of the XCA colloids remain inside the alginate beads and retain 67% of the original activity. In contrast, free cellulase immobilized in the alginate beads loses its activity completely after 10 cycles. The strategy can also be used to prepare other types of cross-linked enzyme aggregates with high uniformity. Copyright © 2016 Elsevier B.V. All rights reserved.

  7. Pullulan/dextran/nHA macroporous composite beads for bone repair in a femoral condyle defect in rats.

    Directory of Open Access Journals (Sweden)

    Silke Schlaubitz

    Full Text Available The repair of bone defects is of particular interest for orthopedic, oral, maxillofacial, and dental surgery. Bone loss requiring reconstruction is conventionally addressed through bone grafting. Depending on the size and the location of the defect, this method has limits and risks. Biomaterials can offer an alternative and have features supporting bone repair. Here, we propose to evaluate the cellular penetration and bone formation of new macroporous beads based on pullulan/dextran that has been supplemented with nanocrystalline hydroxyapatite in a rat model. Cross-linked beads of 300-500 µm diameters were used in a lateral femoral condyle defect and analyzed by magnetic resonance imaging, micro-computed tomography, and histology in comparison to the empty defects 15, 30, and 70 days after implantation. Inflammation was absent for both conditions. For empty defects, cellularisation and mineralization started from the periphery of the defect. For the defects containing beads, cellular structures filling out the spaces between the scaffolds with increasing interconnectivity and trabecular-like organization were observed over time. The analysis of calcified sections showed increased mineralization over time for both conditions, but was more pronounced for the samples containing beads. Bone Mineral Density and Bone Mineral Content were both significantly higher at day 70 for the beads in comparison to empty defects as well as compared with earlier time points. Analysis of newly formed tissue around the beads showed an increase of osteoid tissue, measured as percentage of the defect surface. This study suggests that the use of beads for the repair of small size defects in bone may be expanded on to meet the clinical need for a ready-to-use fill-up material that can favor bone formation and mineralization, as well as promote vessel ingrowth into the defect site.

  8. Ionically crosslinked alginate-carboxymethyl cellulose beads for the delivery of protein therapeutics

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Min Sup; Park, Sang Jun; Gu, Bon Kang [Laboratory of Tissue Engineering, Korea Institute of Radiological and Medical Science, Seoul 139-240 (Korea, Republic of); Kim, Chun-Ho, E-mail: chkim@kcch.re.kr [Laboratory of Tissue Engineering, Korea Institute of Radiological and Medical Science, Seoul 139-240 (Korea, Republic of)

    2012-12-01

    Highlights: Black-Right-Pointing-Pointer We prepared Fe{sup 3+} crosslinked alginate-carboxymethyl cellulose (AC) beads. Black-Right-Pointing-Pointer Different surface and inner morphology of AC beads were observed on volume of CMC. Black-Right-Pointing-Pointer AC beads showed minimum swelling degree in acidic condition. Black-Right-Pointing-Pointer Protein release from AC beads was to control in gastrointestinal condition. - Abstract: We developed Fe{sup 3+}-crosslinked alginate-carboxymethyl cellulose (AC) beads in various volume ratios by dropping an AC solution into a ferric chloride solution to form protein therapeutic carrier beads. Scanning electron microscopy revealed that the roughness and pore size of the crosslinked beads increased with the volume ratio of the carboxymethyl cellulose. Fourier transform-infrared analysis revealed the formation of a three-dimensional bonding structure between the anionic polymeric chains of AC and the Fe{sup 3+} ions. The degree of swelling and the release profile of albumin from the beads were investigated under simulated gastrointestinal conditions (pH 1.2, 4.5, and 7.4). The Fe{sup 3+}-crosslinked AC beads displayed different degrees of swelling and albumin release for the various AC volume ratios and under various pH conditions. An in vitro release test was used to monitor the controlled release of albumin from the AC beads under simulated gastrointestinal conditions over 24 h. The Fe{sup 3+}-crosslinked AC beads protected and controlled the release of protein, demonstrating that such beads present a promising protein therapeutic carrier for the oral delivery.

  9. The effect of wax on compaction of microcrystalline cellulose beads made by extrusion and spheronization.

    Science.gov (United States)

    Iloañusi, N O; Schwartz, J B

    1998-01-01

    The effect of wax on the deformation behavior and compression characteristics of microcrystalline cellulose (Avicel PH-101) and acetaminophen (APAP) beads is described. Beads of Avicel PH-101 and APAP formulations were prepared using extrusion and spheronization technology. A waxy material, glyceryl behenate, N.F. (Compritol), was added to the formulations in amounts ranging from 10% to 70% of total solid weight. Beads with a selected particle size range of 16-30 mesh were compressed with an instrumented single punch Manesty F press utilizing a 7/16-in. flat-faced tooling set. Compaction profiles were generated for the tablets to evaluate the effect of wax on the densification of beads containing wax. Beads made without wax (the control formulation) required greater compression forces to form cohesive tablets. As the amount of wax in the bead formulation was increased, the beads become more plastic and compressible. The Heckel equation which relates densification to compression pressure was used to evaluate the deformation mechanisms of the bead formulations. The analysis shows that as the level of wax in the bead formulation is increased, the yield pressure decreases, indicating that the beads densify by a plastic deformation mechanism.

  10. Tailored beads made of dissolved cellulose - Investigation of their drug release properties

    DEFF Research Database (Denmark)

    Yildir, Emrah; Kolakovic, Ruzica; Genina, Natalja;

    2013-01-01

    In the frame of this work, we have investigated drug entrapping and release abilities of new type of porous cellulose beads (CBs) as a spherical matrix system for drug delivery. For that purpose, CBs prepared with three different methods were used as drug carriers and three compounds, anhydrous...... efficacy. Also, the drug release rates were controlled by solubility of model drugs (diffusion controlled release). In conclusion, CBs from dissolved cellulose show promise in achieving controlled drug delivery. © 2013 Elsevier B.V. All rights reserved....

  11. STUDY ON THE IMMOBILIZATION OF PAPAIN WITH A MACROPOROUS BEAD CARRIER OF COPOLYMER CONTAINING MONOMER UNITS OF N-AMINOETHYL ACRYLAMIDE AND VINYL ALCOHOL

    Institute of Scientific and Technical Information of China (English)

    Yan-feng Li; Jun-rong Li; Lian-di Fu; Yao-zeng Li

    2000-01-01

    A kind of macroporous bead carrier of copolymer containing monomer units ofN-aminoethyl acrylamide and vinyl alcohol was synthesized, i.e. the MR-AA carrier. Papain was immobilized on the carrier using glutaraldehyde as the coupling agent. The enzymatic activity of the immobilized papain was compared with free papain using casein as a substrate, and the effects of glutaraldehyde concentration, pH, temperature, time and papain amount added on the activity recovery were also investigated. The results show that the MR-AA carrier contains reactive primary amine groups, hydrophilic amido links and hydroxyl groups, as well as macroporous structures based on its matrix (MR-AV matrix), furthermore, the activity recovery of papain in the immobilization could reach 48%~58%. In comparison with free papain, the resulting immobilized papain exhibits a remarkable thermostability and better reusability.

  12. Biomimetic Mineralization on a Macroporous Cellulose-Based Matrix for Bone Regeneration

    OpenAIRE

    2013-01-01

    The aim of this study is to investigate the biomimetic mineralization on a cellulose-based porous matrix with an improved biological profile. The cellulose matrix was precalcified using three methods: (i) cellulose samples were treated with a solution of calcium chloride and diammonium hydrogen phosphate; (ii) the carboxymethylated cellulose matrix was stored in a saturated calcium hydroxide solution; (iii) the cellulose matrix was mixed with a calcium silicate solution in order to introduce ...

  13. High effective adsorption of organic dyes on magnetic cellulose beads entrapping activated carbon.

    Science.gov (United States)

    Luo, Xiaogang; Zhang, Lina

    2009-11-15

    Maghemite (gamma-Fe(2)O(3)) nanoparticles were created with a submerged circulation impinging stream reactor (SCISR) from FeCl(3) x 6H(2)O and FeCl(2).4H(2)O by using precipitation followed by oxidation. Subsequently, by blending cellulose with the Fe(2)O(3) nanoparticles and activated carbon (AC) in 7 wt% NaOH/12 wt% urea aqueous solution pre-cooled to -12 degrees C, millimeter-scale magnetic cellulose beads, coded as MCB-AC, was fabricated via an optimal dropping technology. The cellulose beads containning Fe(2)O(3) nanoparticles exhibited sensitive magnetic response, and their recovery could facilitate by applying a magnetic field. The adsorption and desorption of the organic dyes on MCB-AC were investigated to evaluate the removal of dyes (methyl orange and methylene blue) with different charges from aqueous solution. Their adsorption kinetics experiments were carried out and the data were well fitted by a pseudo-second-order equation. The results revealed that the MCB-AC sorbent could efficiently adsorb the organic dyes from wastewater, and the used sorbents could be recovered completely. Therefore, we developed a highly efficient sorbent, which were prepared by using simple and "green" process, for the applications on the removal of hazardous materials.

  14. High effective adsorption of organic dyes on magnetic cellulose beads entrapping activated carbon

    Energy Technology Data Exchange (ETDEWEB)

    Luo Xiaogang [Department of Chemistry, Wuhan University, Wuhan 430072 (China); Zhang Lina, E-mail: lnzhang@public.wh.hb.cn [Department of Chemistry, Wuhan University, Wuhan 430072 (China)

    2009-11-15

    Maghemite ({gamma}-Fe{sub 2}O{sub 3}) nanoparticles were created with a submerged circulation impinging stream reactor (SCISR) from FeCl{sub 3}.6H{sub 2}O and FeCl{sub 2}.4H{sub 2}O by using precipitation followed by oxidation. Subsequently, by blending cellulose with the Fe{sub 2}O{sub 3} nanoparticles and activated carbon (AC) in 7 wt% NaOH/12 wt% urea aqueous solution pre-cooled to -12 deg. C, millimeter-scale magnetic cellulose beads, coded as MCB-AC, was fabricated via an optimal dropping technology. The cellulose beads containning Fe{sub 2}O{sub 3} nanoparticles exhibited sensitive magnetic response, and their recovery could facilitate by applying a magnetic field. The adsorption and desorption of the organic dyes on MCB-AC were investigated to evaluate the removal of dyes (methyl orange and methylene blue) with different charges from aqueous solution. Their adsorption kinetics experiments were carried out and the data were well fitted by a pseudo-second-order equation. The results revealed that the MCB-AC sorbent could efficiently adsorb the organic dyes from wastewater, and the used sorbents could be recovered completely. Therefore, we developed a highly efficient sorbent, which were prepared by using simple and 'green' process, for the applications on the removal of hazardous materials.

  15. Calcium alginate-carboxymethyl cellulose beads for colon-targeted drug delivery.

    Science.gov (United States)

    Agarwal, Tarun; Narayana, S N Gautham Hari; Pal, Kunal; Pramanik, Krishna; Giri, Supratim; Banerjee, Indranil

    2015-04-01

    The present study delineates preparation, characterization and application of calcium alginate (CA)-carboxymethyl cellulose (CMC) beads for colon-specific oral drug delivery. Here, we exploited pH responsive swelling, mucoadhesivity and colonic microflora-catered biodegradability of the formulations for colon-specific drug delivery. The CA-CMC beads were prepared by ionic gelation method and its physicochemical characterization was done by SEM, XRD, EDAX, DSC and texture analyzer. The swelling and mucoadhesivity of the beads was found higher at the simulated colonic environment. Variation was more prominent in compositions with lower CMC concentrations. CA-CMC formulations degraded slowly in simulated colonic fluid, however the degradation rate increased drastically in the presence of colonic microflora. In vitro release study of anticancer drug 5-fluorouracil (5-FU) showed a release (>90%) in the presence of colonic enzymes. A critical analysis of drug release profile along with FRAP (fluorescence recovery after photobleaching) study revealed that the presence of CMC in the formulation retarded the release rate of 5-FU. 5-FU-loaded formulations were tested against colon adenocarcinoma cells (HT-29). Cytotoxicity data, nuclear condensation-fragmentation and apoptosis analysis (by flow cytometry) together confirmed the therapeutic potential of the CA-CMC formulations. In conclusion, CA-CMC beads can be used for colon-specific drug delivery.

  16. Taguchi design and equilibrium modeling for fluoride adsorption on cerium loaded cellulose nanocomposite bead.

    Science.gov (United States)

    Santra, Dhiman; Joarder, Rajib; Sarkar, Mitali

    2014-10-13

    The cooperative influence of operational variables for fluoride adsorption on cerium loaded cellulose nanocomposite bead (CCNB) was assessed using Taguchi design tool. The percentage contribution of each operational variable was determined. The solution pH, with a maximum contribution of 80.78%, indicates its highest influence on the response, the adsorption percent of fluoride. The quality and validity of the experimental design were assessed from ANOVA and subsequently by the confirmation experiment. The equilibrium adsorption data showed that the Temkin isotherm is the most suited one compared to the Langmuir and Freundlich model. It is found that almost 90% adsorbed fluoride can be eluted with 0.01 (N) NaOH and the regenerated bead can successively be reused for at least three times. Copyright © 2014 Elsevier Ltd. All rights reserved.

  17. Biomimetic Mineralization on a Macroporous Cellulose-Based Matrix for Bone Regeneration

    Directory of Open Access Journals (Sweden)

    Odeta Petrauskaite

    2013-01-01

    Full Text Available The aim of this study is to investigate the biomimetic mineralization on a cellulose-based porous matrix with an improved biological profile. The cellulose matrix was precalcified using three methods: (i cellulose samples were treated with a solution of calcium chloride and diammonium hydrogen phosphate; (ii the carboxymethylated cellulose matrix was stored in a saturated calcium hydroxide solution; (iii the cellulose matrix was mixed with a calcium silicate solution in order to introduce silanol groups and to combine them with calcium ions. All the methods resulted in a mineralization of the cellulose surfaces after immersion in a simulated body fluid solution. Over a period of 14 days, the matrix was completely covered with hydroxyapatite crystals. Hydroxyapatite formation depended on functional groups on the matrix surface as well as on the precalcification method. The largest hydroxyapatite crystals were obtained on the carboxymethylated cellulose matrix treated with calcium hydroxide solution. The porous cellulose matrix was not cytotoxic, allowing the adhesion and proliferation of human osteoblastic cells. Comparatively, improved cell adhesion and growth rate were achieved on the mineralized cellulose matrices.

  18. Preparation of reactive macroporous polymeric beads for high-performance liquid chromatography applications: Polymerization, surface modification and characterization

    Science.gov (United States)

    Liang, Yi-Chun

    Several stationary phases for high performance liquid chromatography (HPLC) based on synthetic polymers with controlled pore structures and surface chemistries have been prepared and characterized. The first part of the research is focused on the control of pore structure of reactive beads prepared from functional monomers such as 2,3-epoxypropyl vinylbenzyl ether and 2,3-epoxypropyl vinylbenzyl ether with divinylbenzene used as a crosslinker. Due to a relatively large difference in polarities of these two functional monomers, a new porogenic system had to be developed for the preparation of monodisperse beads from 2,3-epoxypropyl vinylbenzyl ether. In contrast, polymerization conditions similar to those used for the preparation of poly(styrene-co-divinylbenzene) beads can be used for the systems involving chloromethylstyrene and divinylbenzene. An extensive study of the effects of various polymerization parameters on the properties of these reactive beads was carried out in order to achieve fine control over the degree of functionalization and pore structure. The second part of the research is focused on the surface modification of reactive beads prepared in the previous study for the HPLC separation of enantiomers. The performance of our chiral stationary phases (CSP) with brush-type selectors was comparable to the best silica-based chiral separation media. As a part of this study, polymeric CSPs with different linkages, tethers, loading levels, and backbone structures were prepared and characterized. Another series of CSPs were prepared from beads functionalized with a poly(propylene imine) dendrimer tether. A high coupling efficiency with the chiral selector was characteristic of the polymer support modified with dendrimers, and these dendritic supports demonstrated the substantial contribution of linkers with multiple functionalities originating from a single surface site to the selectivity and efficiency of the polymer based separation media.

  19. Preoperative cellulose porous beads for therapeutic embolization of meningioma: provocation test and technical considerations

    Energy Technology Data Exchange (ETDEWEB)

    Kai, Yutaka; Morioka, Motohiro; Yano, Shigetoshi; Nakamura, Hideo; Makino, Keishi; Mizuno, Takamasa; Takeshima, Hideo; Kuratsu, Jun-ichi [Kumamoto University, Department of Neurosurgery, Graduate School of Medical Sciences, Kumamoto (Japan); Hamada, Jun-ichiro [Kanazawa University, Department of Neurosurgery, Graduate School of Medical Sciences, Kanazawa (Japan)

    2007-05-15

    Cellulose porous beads (CPBs) are exceptionally uniform in size and nonabsorbable and they provide highly effective tumor devascularization. The risk of cranial nerve palsy must not be overlooked when embolization with CPBs is considered in meningioma patients. We attempted to identify patients at risk of cranial nerve palsy after meningioma embolization. Prior to preoperative superselective embolization with 200 {mu}m diameter CPBs, 141 patients with meningioma underwent provocation test with lidocaine and amytal. They were divided into two groups on the basis of whether they were or were not considered eligible for embolization. We evaluated the differences between the two groups with respect to tumor anatomy, angiographic findings, and clinical presentation and recorded complications associated with the embolization of the meningioma. Of the 141 patients, 128 underwent CPB embolization (group 2); 13 were not embolized because their provocation test results were positive (group 1, n = 11) or because they showed vasospasm (n = 2). Group 1 patients had meningioma in the cavernous sinus or petroclival region. Characteristically, the feeders were of middle meningeal artery origin and exhibited a posteromedial course toward the petrous apex or cavernous sinus. In group 2 patients the middle meningeal artery was the feeder, but it lacked branches coursing posteromedially. Three of these patients experienced complications which included intratumoral hemorrhage (n = 2) and post-embolization hearing disturbance (n = 1). Patients with meningioma whose tumor-feeding arteries run posteromedially toward the petrous apex or cavernous sinus are at increased risk of post-embolization cranial nerve palsy. Appropriate protocols, including lidocaine and amytal provocation tests, may reduce the risk of complications after CPB embolization of the external carotid territory in this group of patients. (orig.)

  20. Macropores and macropore transport

    DEFF Research Database (Denmark)

    Iversen, Bo Vangsø; Lamandé, Mathieu; Torp, Søren Bent

    2012-01-01

    a stronger relationship was found at saturation. Results of a test of the number of soil columns needed for a representative distribution of macropores for the measurement of saturated hydraulic conductivity indicated that approximately six soil columns were enough. Our work suggests that integrating......Preferential transport of water through soil macropores is a governing process in the facilitated transport of strongly sorbing compounds. The aim of this study was to investigate the relationships between macropore density and the hydraulic conductivity of the soil and to test the sampling...... representativeness of soil columns for the measurement of saturated hydraulic conductivity. Macropore density was determined in three horizons in four typical, Danish soil types (third year of pasture) and saturated hydraulic conductivity and near-saturated hydraulic conductivity were measured in the laboratory...

  1. Efficient Pb(II) removal using sodium alginate-carboxymethyl cellulose gel beads: Preparation, characterization, and adsorption mechanism.

    Science.gov (United States)

    Ren, Huixue; Gao, Zhimin; Wu, Daoji; Jiang, Jiahui; Sun, Youmin; Luo, Congwei

    2016-02-10

    Alginate-carboxymethyl cellulose (CMC) gel beads were prepared in this study using sodium alginate (SA) and sodium CMC through blending and cross-linking. The specific surface area and aperture of the prepared SA-CMC gel beads were tested. The SA-CMC structure was characterized and analyzed via infrared spectroscopy, scanning electron microscopy, and energy-dispersive X-ray spectroscopy. Static adsorption experiment demonstrated that Pb(II) adsorption of SA-CMC exceeded 99% under the optimized conditions. In addition, experiments conducted under the same experimental conditions showed that the lead ion removal efficiency of SA-CMC was significantly higher than that of conventional adsorbents. The Pb(II) adsorption process of SA-CMC followed the Langmuir adsorption isotherm, and the dynamic adsorption model could be described through a pseudo-second-order rate equation. Pb(II) removal mechanisms of SA-CMC, including physical, chemical, and electrostatic adsorptions, were discussed based on microstructure analysis and adsorption kinetics. Chemical adsorption was the main adsorption method among these mechanisms. Copyright © 2015 Elsevier Ltd. All rights reserved.

  2. Formulation Optimization and Evaluation of Probiotic Lactobacillus sporogenes-Loaded Sodium Alginate with Carboxymethyl Cellulose Mucoadhesive Beads Using Design Expert Software

    Directory of Open Access Journals (Sweden)

    Himanshu K. Solanki

    2016-01-01

    Full Text Available The present study deals with the formulation optimization of sodium carboxymethyl cellulose-alginate mucoadhesive beads containing probiotic Lactobacillus sporogenes through ionotropic gelation using 32 factorial design. The effect of sodium carboxymethyl cellulose-alginate concentration on the probiotic entrapment efficiency (PEE, %, viability in simulated gastric fluid (log CFU/g, and mucoadhesion over 8 hr (% was optimized. The optimized beads containing probiotic Lactobacillus sporogenes showed entrapment efficiency of 93.7±1.97%, viability of probiotic in simulated gastric fluid (log CFU/g of 9.34, mucoadhesion of 71.75±1.38%, and mean diameter of 1.21±0.11 mm. The beads were also characterized by SEM, FTIR, and XRD. The swelling and degradation of these beads were influenced by pH of the test medium. Finally, stability tests performed at room temperature (25~28°C highlighted a bacterial viability of about 91% and 86% after 1 and 2 months, respectively. The advantageous properties of probiotic Lactobacillus sporogenes-loaded mucoadhesive beads make them suitable for incorporation in functional food and/or pharmaceutical products.

  3. Protein adsorption in two-dimensional electrochromatography packed with superporous and microporous cellulose beads

    Institute of Scientific and Technical Information of China (English)

    Dongmei WANG; Guodong JIA; Liang XU; Xiaoyan DONG; Yan SUN

    2009-01-01

    Anion-exchange superporous cellulose (DEAE-SC) and microporous cellulose (DEAE-MC) adsorbents were packed in an electrochromatographic column, and the effect of external electric field (eEF) on the dynamic adsorption was investigated. The column was designed to provide longitudinal, transverse or 2-dimensional (2D) eEF. It was found that the electro-kinetic effect caused by the introduction of an electric field played an important role in the dynamic adsorption of bovine serum albumin to the adsorbents. The dynamic binding capacity (DBC) in the presence of2D eEF was higher than in the presence of a one-dimensional eEF. The effect of flow velocity on the DBC of the two adsorbents was also demonstrated. It was found that the effect of electric field. on the DEAE-MC column was more remarkable than that on the DEAE-SC column at the same flow rate, whereas the DEAE-SC column showed higher DBC and adsorption efficiency (AE) than the DEAE-MC column. With increasing flow rate, the DEAE-SC column could still offer high DBC and AE in the presence of the 2D eEF. For example, a DBC of 21.4 mg/mL and an AE of 57.7% were obtained even at a flow rate as high as 900 cm/h. The results indicate that the 2D electrochromatography packed with the superporous cellulose adsorbent is promising for high-speed protein chromatography.

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

    Science.gov (United States)

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

    2016-11-01

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

  5. Effects of hydrophilic macropore fillings and coatings on the infiltration into water repellent porous media

    Science.gov (United States)

    Suetsugu, A.; Mori, Y.

    2012-12-01

    Macropores generate rapid flow paths in the surface soils by their high permeability under saturated/near-saturated moisture conditions. In natural soils, some macropores are filled/coated with various materials including decayed plant roots (Meek et al., 1989), exudates from plants/soil organisms (Jegou et al., 2001), iron oxides or other precipitates from preferentially-introduced solutes/colloids to the macropores (Rasmussen et al., 2001), or the surrounding soils with reduced bulk density (Ela et al., 1992). When we expect infiltration into water repellent soils through macropores or hydrophilic patches created from the macropore cementation processes, hydrophilicity of the macropore fillings/coatings should be understood. In the present study, we conducted an infiltration experiment with water repellent porous media and some macropore fillings/coatings, in order to clarify the roles of hydrophilic macropore fillings/coatings in infiltration. Ponding depth and flow distribution were monitored with a micro-focus X-ray computational tomography apparatus (SMX-90CT, Shimadzu Corp., Kyoto, Japan) at 90 kV and 110 μA. Dilute CsCl(aq) (density: 1.04 Mg m-3) was used as the contrast media to avoid density-driven alteration of the flows. Water repellency of the samples was evaluated by the water drop penetration time (WDPT, Van't Woudt, 1959). A glass beads (mean diameter: 0.46 mm, BZ-04, ASONE Corp., Osaka, Japan) was used as water repellent porous media. The glass beads sample was packed in 50-mL polypropylene centrifugation tubes at 1.55 Mg m-3 bulk density. A 2-mm hole was made at the bottom of each centrifugation tube for ventilation. The hole was covered with mesh cloth. Macroporous structure was made at the center of each tube from the surface. Each macroporous structure had 4-mm diameter and 30-mm length. Six types of macropores were prepared including 1) no macropore, 2) empty macropore, 3) an aluminum (Al) pipe (4-mm inner diameter, 5-mm outer diameter), 4) a

  6. Macroporous silica–alumina composites with mesoporous walls

    Indian Academy of Sciences (India)

    Gautam Gundiah

    2001-04-01

    Macroporous silica–alumina composites with mesopores have been prepared by employing polymethylmethacrylate beads as templates in the presence of the cationic surfactant, N-cetyl-N,N,N-trimethylammonium bromide. The Si/Al ratio in the composites has been varied between 4.5 and 48 and the occurrence of mesopores has been verified by X-ray diffraction. The surface areas of the samples vary between 676 and 1038 m2g–1, with the highest value in the sample with Si/Al = 48.

  7. Formation of a macro-porous SiO2 layer as an anti-reflective coating on glass substrates.

    Science.gov (United States)

    Park, No-Kuk; Kim, Yong Sul; Kim, Min Jung; Lee, Tae Jin; Lee, Seung Hyun; Lee, Seung Hun

    2013-11-01

    A macro-porous silica layer, consisting of a silica layer with macro-sized pores, was formed as an antireflective material on glass substrates. The silica layer and macro-pores were formed by the oxidative thermal decomposition of tetra-ethylorthorsilicate (TEOS) used as the precursor and polystyrene (PS) spherical beads used as the polymer template for the macro-pores at high temperatures. The size of pores was determined by the size of PS beads in the antireflective agent solution. The size of the PS spherical beads can be controlled by changing the concentration of styrene monomer, and the porosity of the macro pore in the silica layer could be controlled by the TEOS/PS ratio. The optimal thermal treating temperature for the formation of a macro-porous silica layer was found to be 650 degrees C. The size of the spherical type macro pores formed in the silica layer on the glass substrate was 100-150 nm. UV-Vis spectrophotometry confirmed the improved antireflective properties of the glass substrate with the macro-porous silica layer.

  8. Hierarchically templated beads with tailored pore structure for phosphopeptide capture and phosphoproteomics

    DEFF Research Database (Denmark)

    Wierzbicka, Celina; Torsetnes, Silje B.; Jensen, Ole N.

    2017-01-01

    and crosslinkers inside the pores of macroporous silica beads with both free and immobilized template. In the final step the silica was removed by fluoride etching resulting in mesoporous polymer replicas with narrow pore size distributions, pore diameters ≈ 10 nm and surface area > 260 m2 g-1. The beads displayed......Two templating approaches to produce imprinted phosphotyrosine capture beads with a controllable pore structure are reported and compared with respect to their ability to enrich phosphopeptides from a tryptic peptide mixture. The beads were prepared by the polymerization of urea-based host monomers...

  9. Monosized macroporous resins with epoxy groups and their structure and gel chromatography properties

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The monosized macroporous-polymer beads based on cross-linked poly(glycidyl methacrylate) have been synthesized by a new improving method--combining dispersion polymerization with swelling polymerization and polymeric solution porogens. The structure and gel chromatographic properties of the resins have been studied. The resins as matrix materials of various types of high performance liquid chromatography (HPLC) packings possess excellent separation properties

  10. Preparation of Macro-Porous Tin Oxide for Sensing of Sulfur Compound.

    Science.gov (United States)

    Park, No-Kuk; Lee, Tae Hoon; Sung, Yeon Baek; Kim, Yong Sul; Lee, Tae Jin

    2016-03-01

    Macro-porous tin oxide was prepared as an enhanced sensing material for sulfur compounds, such as hydrogen sulfide. Poly-methyl-methacrylate (PMMA) was used as a template for the formation of macro-pores. Tin chloride was used as a precursor for the synthesis of tin oxide, and was impregnated over PMMA beads using a rotary vacuum evaporator. The solid Sn/PMMA material was treated thermally for 4 h at 600 degrees C. The porous morphology of tin oxide prepared in this study was observed by scanning electron microscopy. The surface area of this material measured by the nitrogen adsorption method was approximately 56 m2/g. The crystal structure of the porous material analyzed by XRD was a typical structure of tin oxide. The response of macro-porous tin oxide as a chemical gas sensor was measured using an I-V source meter and the change in signal was observed with the repeated injection of hydrogen sulfide and air. The sensing tests for macro-porous tin oxide were carried out at 200 degrees C and the fast response of macro-porous sensing material was also confirmed.

  11. Microfluidic Bead Suspension Hopper

    OpenAIRE

    Price, Alexander K.; MacConnell, Andrew B.; Paegel, Brian M.

    2014-01-01

    Many high-throughput analytical platforms, from next-generation DNA sequencing to drug discovery, rely on beads as carriers of molecular diversity. Microfluidic systems are ideally suited to handle and analyze such bead libraries with high precision and at minute volume scales; however, the challenge of introducing bead suspensions into devices before they sediment usually confounds microfluidic handling and analysis. We developed a bead suspension hopper that exploits sedimentation to load b...

  12. Macroporous glass monoliths prepared from powdered niobium phosphate glass by fast sintering

    Energy Technology Data Exchange (ETDEWEB)

    Lacerda Mauricio, Vitor; Alves, Oswaldo Luiz; Odone Mazali, Italo, E-mail: mazali@iqm.unicamp.br

    2011-03-15

    Macroporous monoliths were prepared by very fast sintering (between 3 and 15 min) of niobophosphate glass powders at low temperature (1018 K) using cellulose as a foaming agent. The porous materials were analyzed by thermal analysis, Raman spectroscopy, scanning electron microscopy and powder X-ray diffraction, and further investigated using X-ray microtomography, a non-destructive technique capable of reconstructing three-dimensional models of samples and providing structural measurements. The progression of the porosity of the monoliths depends on the sintering time (3 to 15 min) and the amount (up to 50% in mass) of cellulose used. The macroporous glass monoliths may find application in integrated chemical systems and in filtering processes.

  13. Template synthesis of ordered macroporous hydroxyapatite bioceramics.

    Science.gov (United States)

    Ji, Lijun; Jell, Gavin; Dong, Yixiang; Jones, Julian R; Stevens, Molly M

    2011-08-28

    Hydroxyapatite has found wide application in bone tissue engineering. Here we use a macroporous carbon template to generate highly ordered macroporous hydroxyapatite bioceramics composed of close-packed hollow spherical pores with interconnected channels. The template has advantages for the preparation of ordered materials.

  14. Preparation of Carboxyl Methyl Cellulose, Modified Bentonite Blend Gel Beads and Their Performance on Slow Release of Fertilizer%羧甲基纤维素钠-改性膨润土复合凝胶的制备及缓释性能

    Institute of Scientific and Technical Information of China (English)

    张磊; 张根林; 鲁建江; 石全英

    2012-01-01

    采用羧甲基纤维素钠(CMC)凝胶加入改性膨润土的方法制备缓释肥料,考察CMC、膨润土和尿素质量浓度及交联剂浓度对羧甲基纤维素钠-改性膨润土复合凝胶缓释效果的影响,并利用扫描电镜进行表征.结果表明,在凝胶中加入膨润土有效的延长了尿素释放时间,质量浓度30 g/L的CMC、25 g/L的膨润土、50 g/L的尿素及0.10 mol/L交联剂制得的复合凝胶缓释效果最佳,释放80%的尿素需要20 d;利用扫描电镜,可以观察到在缓释颗粒表面存在孔洞,整个释放过程中缓释颗粒的整体结构依然存在,说明颗粒有一定缓释能力.%A novel slow release fertilizer was made from modified bentonite, sodium salt of caboxy methyl cellulose, and urea through cross-linking chemical reaction. Factors affecting the performance on slow release of fertilizer such as degree of modified bentonite, sodium salt of caboxy methyl cellulose, urea, and cross-linking agent, were discussed in detail. The results indicated the addition of modified bentonite extended the releasing time; The optimal conditions were found to be as follows: mass concentration of sodium salt of carboxymethyl cellulose modified bentonite 30 g/L, modified bentonite 25 g/L, urea 50 g/L,and degree of cross-linking agent 0. 10 mol/L; 80% of urea released in 20 days. There were many small holes on the surface of the blend gel beads and the structures existed through the release process, which indicated the slow release character of the beads. This slow release fertilizer is a good example for application and promotion of the new, green and controlled-release fertilizers.

  15. A Magnetic Bead Actuator

    NARCIS (Netherlands)

    Derks, R.; Prins, M.W.J.; Wimberger-Friedl, R.

    2006-01-01

    Actuation principles of superparamagnetic beads applicable on biosensing (at single beads and chain orderning) are studied in this report. This research can be used to develop new techniques that are able to accelerate bio-assays. An experimental setup containing a sub-microliter fluid volume

  16. Nitrogen Doped Macroporous Carbon as Electrode Materials for High Capacity of Supercapacitor

    Directory of Open Access Journals (Sweden)

    Yudong Li

    2017-01-01

    Full Text Available Nitrogen doped carbon materials as electrodes of supercapacitors have attracted abundant attention. Herein, we demonstrated a method to synthesize N-doped macroporous carbon materials (NMC with continuous channels and large size pores carbonized from polyaniline using multiporous silica beads as sacrificial templates to act as electrode materials in supercapacitors. By the nice carbonized process, i.e., pre-carbonization at 400 °C and then pyrolysis at 700/800/900/1000 °C, NMC replicas with high BET specific surface areas exhibit excellent stability and recyclability as well as superb capacitance behavior (~413 F ⋅ g−1 in alkaline electrolyte. This research may provide a method to synthesize macroporous materials with continuous channels and hierarchical pores to enhance the infiltration and mass transfer not only used as electrode, but also as catalyst somewhere micro- or mesopores do not work well.

  17. Soil Macropore Structure Characterized by X-Ray Computed Tomography

    Institute of Scientific and Technical Information of China (English)

    FENG Jie; ZHANG Jia-Bao; ZHU An-Ning; BI Jing-Wei

    2003-01-01

    Undisturbed soil core with many macropores and disturbed soil core with only one macropore (diameter is 10 mm) were probed by x-ray computed tomography (CT). The size, number, shape and continuity of macropores in the transverse and vertical sections of soil were characterized using CT scanning images. The probability densities of macropores in the transverse section of soil core exhibited a logarithmic Γ distribution.Results indicated that CT scanning was a promising nondestructive method for characterizing macropores in soils.

  18. Scaling hydraulic properties of a macroporous soil

    Science.gov (United States)

    Mohanty, Binayak P.

    1999-06-01

    Macroporous soils exhibit significant differences in their hydraulic properties for different pore domains. Multimodal hydraulic functions may be used to describe the characteristics of multiporosity media. I investigated the usefulness of scaling to describe the spatial variability of hydraulic conductivity (K(-h)) functions of a macroporous soil in Las Nutrias, New Mexico. Piecewise-continuous hydraulic conductivity functions suitable for macroporous soils in conjunction with a hybrid similar media-functional normalization scaling approach were used. Results showed that gravity-dominated flow and the related hydraulic conductivity (K(minus;h) functions of the macropore region are more readily scalable than capillary-dominated flow properties of the mesopore and micropore regions. A possible reason for this behavior is that gravity-dominated flow in the larger pores is mostly influenced by the pore diameter which remains more uniform as compared to tortuous mesopores and micropores with variable neck and body sizes along the pore length.

  19. Deep Ultraviolet Macroporous Silicon Filters Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This SBIR Phase I proposal describes a novel method to make deep and far UV optical filters from macroporous silicon. This type of filter consists of an array of...

  20. Macroporous ultramicroelectrodes for improved electroanalytical measurements.

    Science.gov (United States)

    Szamocki, Rafael; Velichko, Alexandra; Holzapfel, Christian; Mücklich, Frank; Ravaine, Serge; Garrigue, Patrick; Sojic, Neso; Hempelmann, Rolf; Kuhn, Alexander

    2007-01-15

    Recent work on the preparation of highly organized macroporous electrodes and nanoporous ultramicroelectrodes has been combined and extended to elaborate macroporous ultramicroelectrodes (UMEs) by template synthesis using colloidal crystals and following two different and complementary methods. On the one hand, arched porous UMEs were prepared, and on the other hand, cylindrical porous UMEs were obtained by using cavity UMEs. These macroporous UMEs have an active surface area which is up to 2 orders of magnitude higher compared to that of a classical disk UME as characterized by cyclic voltammetry. To study their analytical performance, the macroporous UMEs have been modified with a redox-active thiol and also a model bioelectrocatalytical system containing a redox mediator, a cofactor, and glucose-dehydrogenase. In both cases the electrochemical signal is amplified by up to 2 orders of magnitude, which increases significantly the analytical performance of such electrodes and therefore opens up new applications for this kind of miniaturized electrochemical system.

  1. Small, porous polyacrylate beads

    Science.gov (United States)

    Rembaum, Alan (Inventor); Yen, Shiao-Ping Siao (Inventor); Dreyer, William J. (Inventor)

    1976-01-01

    Uniformly-shaped, porous, round beads are prepared by the co-polymerization of an acrylic monomer and a cross-linking agent in the presence of 0.05 to 5% by weight of an aqueous soluble polymer such as polyethylene oxide. Cross-linking proceeds at high temperature above about 50.degree.C or at a lower temperature with irradiation. Beads of even shape and even size distribution of less than 2 micron diameter are formed. The beads will find use as adsorbents in chromatography and as markers for studies of cell surface receptors.

  2. Crosslinked, porous, polyacrylate beads

    Science.gov (United States)

    Rembaum, Alan (Inventor); Yen, Shiao-Ping S. (Inventor); Dreyer, William J. (Inventor)

    1977-01-01

    Uniformly-shaped, porous, round beads are prepared by the co-polymerization of an acrylic monomer and a cross-linking agent in the presence of 0.05 to 5% by weight of an aqueous soluble polymer such as polyethylene oxide. Cross-linking proceeds at high temperature above about 50.degree. C or at a lower temperature with irradiation. Beads of even shape and even size distribution of less than 2 micron diameter are formed. The beads will find use as adsorbents in chromatography and as markers for studies of cell surface receptors.

  3. Carbon nanofibers encapsulated in macropores in silicon

    Energy Technology Data Exchange (ETDEWEB)

    Starkov, V.; Red' kin, A. [Institute of Microelectronics Technology and High Purity Materials, RAS, Institutskaya str. 6, Chernogolovka 142432 (Russian Federation)

    2007-05-15

    This work reports on the development of fuel cells electrodes with a porous silicon structure and carbon nanofibers encapsulated in macropores in silicon. It is demonstrated that decomposition of carbon on a Ni catalyst deposited on the pore walls can be used to create a homogeneous carbon nanotube layer that dramatically increases the specific surface area while simultaneously reducing the resistivity of the macroporous silicon layer. (copyright 2007 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  4. A novel microcarrier bead model to investigate bone cell responses to mechanical compression in vitro.

    Science.gov (United States)

    Shelton, R M; el Haj, A J

    1992-12-01

    Periosteal cells grown in macroporous microcarrier bead columns were cyclically loaded with compressive force using a newly developed model. In response to 1/2 h of cyclic compression, RNA synthesis increased significantly by twofold, from 113.4 +/- 19.6 to 260.7 +/- 363 (p < 0.01) after 16 h, whereas DNA synthesis did not increase significantly after 24 h. The microcarrier bead model was calibrated using a linear volume displacement transducer with a range of strain magnitudes applied across the column of 1000-6000 microstrain.

  5. [Fracture of macroporous hydroxyapatite prosthesis].

    Science.gov (United States)

    Adetchessi, A T; Pech-Gourg, G; Metellus, P; Fuentes, S

    2012-12-01

    Different prosthesis implants are offered to perform a cranioplasty after a decompressive craniectomy when autologous bone graft cannot be used. The authors report the case of a 25-year-old man who benefited a unilateral decompressive craniectomy after a severe head trauma. Seven months later, a cranioplasty using custom macroporous hydroxyapatite prosthesis was performed. The postoperative course was marked by a generalized seizure leading to a traumatic head injury. The CT-scan showed a comminutive fracture of the prosthesis and an extradural hematoma. The patient underwent a removal of the fractured prosthesis and an evacuation of the extradural clot. The postoperative course was uneventful with a Glasgow outcome scale score at 5. A second cranioplasty using a polyether ether ketone (PEEK) implant was performed. Among cranioplasty prosthesis solutions, hydroxyapatite implants seem to have similar property to the bone. However, its weak mechanic resistance is an actual problem in patients susceptible to present generalized seizures with consecutive head impact. Hence, in patients with decompressive craniectomy who are exposed to potential brain injury, we favor the use of more resistant implant as PEEK prosthesis.

  6. Preparation of Aminated Macroporous Polyvinyl Alcohol Resins and Evaluation for Bilirubin Adsorption

    Institute of Scientific and Technical Information of China (English)

    WANG Wei-chao; ZHANG Sheng-nan; HU Yue-han; XIE Hui; OU Lai-liang; YU Yao-ting; KONG De-ling; GU Han-qing

    2008-01-01

    In the present study we prepared macroporous polyvinyl alcohol beads. A series of bilirubin adsorbents were generated by immobilization of eight amine agents to the beads as ligands. The adsorption of bilirubin was evaluated by in vitro static and dynamic adsorption tests. The results show that these adsorbents have excellent adsorption efficiency and capacity. Among the eight ligands, trimethylamine (TMA), triethylamine (TEA) and 1,6- hexanediamine(HAD) showed the highest adsorption capacity. The adsorption equilibrium can be achieved in half an hour, and the adsorption percentage of bilirubin was up to 80%. Static electricity and hydrophobic interaction played the main role in bilirubin adsorption, and the adsorption was found to match the monolayer model. The excellent adsorption of these adsorbents indicates their potential in clinical treatment.

  7. Glass bead cultivation of fungi

    DEFF Research Database (Denmark)

    Droce, Aida; Sørensen, Jens Laurids; Giese, H.

    2013-01-01

    Production of bioactive compounds and enzymes from filamentous fungi is highly dependent on cultivation conditions. Here we present an easy way to cultivate filamentous fungi on glass beads that allow complete control of nutrient supply. Secondary metabolite production in Fusarium graminearum...... and Fusarium solani cultivated on agar plates, in shaking liquid culture or on glass beads was compared. Agar plate culture and glass bead cultivation yielded comparable results while liquid culture had lower production of secondary metabolites. RNA extraction from glass beads and liquid cultures was easier...... to specific nutrient factors. •Fungal growth on glass beads eases and improves fungal RNA extraction....

  8. Preformed beading and boxing appliance.

    Science.gov (United States)

    Reddy, J Sashi Deepth; Padmanabhan, T V; Veerareddy, Chandrika; Chandrasekhar, M; Narendra, R

    2013-03-01

    Conventional beading and boxing procedure is time consuming and involves application of heat that might distort green stick compound used for border molding. Earlier studies regarding beading and boxing methods have shown usage of various materials that were disposable and that cannot be recycled. To reduce the time consumed for beading and boxing procedure and to make this procedure cost-effective by using recyclable beading material, "Preformed boxing appliance" with moldable clay meant for beading the secondary impression was used. Secondary impression was supported by 3 studs provided on the floor of the boxing appliance. The cast was poured. The duration for the entire procedure was much less than the conventional procedure.

  9. Preparation of cellulose-based sponges for wound dressing and healing

    OpenAIRE

    2013-01-01

    For healing of chronic or burn wounds, polymeric sponges have been recently applied. Due to a high absorption capacity, noncitotoxicity and good swelling capabilities, for their production natural polymers are often used. In this study, macroporous regenerated cellulose was evaluated as a matrix for wound dressing materials. Active compounds, such as antibiotic neomycin and phenolic compound quercetin were immobilized in the cellulosic matrix aimed to promote wound healing process. Active com...

  10. Preparation of cellulose-based sponges for wound dressing and healing

    NARCIS (Netherlands)

    Kazlauske, J.; Dutschk, Victoria; Liesiene, J.; Dörfel, A.; Vignaesh Sankaran, M.

    2013-01-01

    For healing of chronic or burn wounds, polymeric sponges have been recently applied. Due to a high absorption capacity, noncitotoxicity and good swelling capabilities, for their production natural polymers are often used. In this study, macroporous regenerated cellulose was evaluated as a matrix for

  11. Preparation of cellulose-based sponges for wound dressing and healing

    NARCIS (Netherlands)

    Kazlauske, J.; Dutschk, V.; Liesiene, J.; Dörfel, A.; Vignaesh Sankaran, M.

    2013-01-01

    For healing of chronic or burn wounds, polymeric sponges have been recently applied. Due to a high absorption capacity, noncitotoxicity and good swelling capabilities, for their production natural polymers are often used. In this study, macroporous regenerated cellulose was evaluated as a matrix for

  12. Cellulose is not just cellulose

    DEFF Research Database (Denmark)

    Hidayat, Budi Juliman; Felby, Claus; Johansen, Katja Salomon

    2012-01-01

    or enzymatic hydrolysis of plant cell walls is carried out simultaneously with the application of shear stress, plant cells such as fibers or tracheids break at their dislocations. At present it is not known whether specific carbohydrate binding modules (CBMs) and/or cellulases preferentially access cellulose......Most secondary plant cell walls contain irregular regions known as dislocations or slip planes. Under industrial biorefining conditions dislocations have recently been shown to play a key role during the initial phase of the enzymatic hydrolysis of cellulose in plant cell walls. In this review we...... are not regions where free cellulose ends are more abundant than in the bulk cell wall. In more severe cases cracks between fibrils form at dislocations and it is possible that the increased accessibility that these cracks give is the reason why hydrolysis of cellulose starts at these locations. If acid...

  13. Novel macroporous amphoteric gels: Preparation and characterization

    Directory of Open Access Journals (Sweden)

    S. Kudaibergenov

    2012-05-01

    Full Text Available Macroporous amphoteric gels based on allylamine, methacrylic acid and acrylamide crosslinked by N,N'-methylenebisacrylamide were synthesized by radical copolymerization of monomers in cryoconditions. The composition of cryogels was determined by combination of potentiometric and conductimetric titrations. The morphology of cryogels was evaluated by scanning electron microscope (SEM. Cryogels exhibited sponge-like porous structure with pore size ranging from 50 to 200 μm. The values of the isoelectric points (IEPs determined from the swelling experiments arranged between 3.5 and 4.3. The high adsorption-desorption capacity of amphoteric cryogels with respect to mM and trace concentrations of copper, nickel, and cobalt ions was demonstrated. It was shown that the macroporous amphoteric cryogels are able to adsorb up to 99.9% of copper, nickel, and cobalt ions from 10–3 mol•L–1 aqueous solution.

  14. Macroporous Monolithic Polymers: Preparation and Applications

    Directory of Open Access Journals (Sweden)

    Cecilia Inés Alvarez Igarzabal

    2009-12-01

    Full Text Available In the last years, macroporous monolithic materials have been introduced as a new and useful generation of polymers used in different fields. These polymers may be prepared in a simple way from a homogenous mixture into a mold and contain large interconnected pores or channels allowing for high flow rates at moderate pressures. Due to their porous characteristics, they could be used in different processes, such as stationary phases for different types of chromatography, high-throughput bioreactors and in microfluidic chip applications. This review reports the contributions of several groups working in the preparation of different macroporous monoliths and their modification by immobilization of specific ligands on the products for specific purposes.

  15. Macroporous nanowire nanoelectronic scaffolds for synthetic tissues

    Science.gov (United States)

    Tian, Bozhi; Liu, Jia; Dvir, Tal; Jin, Lihua; Tsui, Jonathan H.; Qing, Quan; Suo, Zhigang; Langer, Robert; Kohane, Daniel S.; Lieber, Charles M.

    2012-11-01

    The development of three-dimensional (3D) synthetic biomaterials as structural and bioactive scaffolds is central to fields ranging from cellular biophysics to regenerative medicine. As of yet, these scaffolds cannot electrically probe the physicochemical and biological microenvironments throughout their 3D and macroporous interior, although this capability could have a marked impact in both electronics and biomaterials. Here, we address this challenge using macroporous, flexible and free-standing nanowire nanoelectronic scaffolds (nanoES), and their hybrids with synthetic or natural biomaterials. 3D macroporous nanoES mimic the structure of natural tissue scaffolds, and they were formed by self-organization of coplanar reticular networks with built-in strain and by manipulation of 2D mesh matrices. NanoES exhibited robust electronic properties and have been used alone or combined with other biomaterials as biocompatible extracellular scaffolds for 3D culture of neurons, cardiomyocytes and smooth muscle cells. Furthermore, we show the integrated sensory capability of the nanoES by real-time monitoring of the local electrical activity within 3D nanoES/cardiomyocyte constructs, the response of 3D-nanoES-based neural and cardiac tissue models to drugs, and distinct pH changes inside and outside tubular vascular smooth muscle constructs.

  16. Hierarchically Structured Monolithic ZSM-5 through Macroporous Silica Gel Zeolitization

    Institute of Scientific and Technical Information of China (English)

    Lei Qian; Zhao Tianbo; Li Fengyan; Zong Baoning; Tong Yangchuan

    2006-01-01

    The hierarchically structured ZSM-5 monolith was prepared through transforming the skeletons of the macroporous silica gel into ZSM-5 by the steam-assisted conversion method. The morphology and monolithic shapes of macroporous silica gel were well preserved. The hierarchically structured ZSM-5 monolith exhibited the hierarchical porosity, with mesopores and macropores existing inside the macroporous silica gel, and micropores formed by the ZSM-5. The products have been characterized properly by using the XRD, SEM and N2 adsorption-desorption methods.

  17. STUDY ON SYNTHESIS OF PVC SERIES OF MACROPOROUS SULFORIC RESINS AND THEIR APPLICATIONS IN CATALYTIC ESTERIFICATION AND WATER TREATMENT

    Institute of Scientific and Technical Information of China (English)

    LIYanfeng; FULiandi; 等

    1999-01-01

    The PVC serves of macroporous sulfonic cation-exchange resins were prepared by the sulfonation of a macroporous PVC bead with concentrated sulfonic acid or chlorosulfonic acid.the resulting sulfonic resin was employed in the investigation of catalytic esterification and solftening of water,The results show that the yields of esters reach 60.0-84.4% according as different fatty acids and alcohols,the refractive indexes of esters obtained resemble those reported in the references basically,meanwhile,345L softened water which holds ≤0.06mmol/L hardness would be prepared by 1 L wet sulfonic resin reusing for 4 times.The resulting sulfonic resins would have 1.6-2.0or 2.5-3.0mmol/g exchange capacity by using concentrated sulfonic acid or chlorosulfonic acid as sulfonating agent,respectively,The sulfonic resin has a macroporous structure taking the morphology with agglomerates of minutely spherical gel particles as characteristic.

  18. Pesticide leaching in macroporous clay soils: field experiment and modeling

    NARCIS (Netherlands)

    Scorza Júnior, R.P.

    2002-01-01

    Keywords : pesticide leaching, macropores, preferential flow, preferential transport, cracked clay soil, pesticide leaching models, groundwater contamination, inverse modeling, bentazone and imidacloprid. The presence of macropores (i.e. shrinkage c

  19. A microhydrodynamic rationale for selection of bead size in preparation of drug nanosuspensions via wet stirred media milling.

    Science.gov (United States)

    Li, Meng; Alvarez, Paulina; Bilgili, Ecevit

    2017-04-02

    Although wet stirred media milling has proven to be a robust process for producing nanoparticle suspensions of poorly water-soluble drugs and thereby enhancing their bioavailability, selection of bead size has been largely empirical, lacking fundamental rationale. This study aims to establish such rationale by investigating the impact of bead size at various stirrer speeds on the drug breakage kinetics via a microhydrodynamic model. To this end, stable suspensions of griseofulvin, a model BCS Class II drug, were prepared using hydroxypropyl cellulose and sodium dodecyl sulfate. The suspensions were milled at four different stirrer speeds (1000-4000rpm) using various sizes (50-1500μm) of zirconia beads. Laser diffraction, SEM, and XRPD were used for characterization. Our results suggest that there is an optimal bead size that achieves fastest breakage at each stirrer speed and that it shifts to a smaller size at higher speed. Calculated microhydrodynamic parameters reveal two counteracting effects of bead size: more bead-bead collisions with less energy/force upon a decrease in bead size. The optimal bead size exhibits a negative power-law correlation with either specific energy consumption or the microhydrodynamic parameters. Overall, this study rationalizes the use of smaller beads for more energetic wet media milling.

  20. Polymeric macroporous formulations for the control release of mosquitocidal Bacillus sphaericus ISPC-8.

    Science.gov (United States)

    Tripathi, Anuj; Hadapad, Ashok B; Hire, Ramesh S; Melo, Jose S; D'Souza, Stanislaus F

    2013-12-10

    Bio-polymeric mosquitocidal formulations were developed for the control release of Bacillus sphaericus ISPC-8 by the immobilization of its spore-crystal complex onto the macroporous polymeric matrices. The biodegradable formulations were synthesized at sub-zero temperature using natural polymeric substrates like agarose, alginate, cellulose, non-adsorbent cotton, wooden cork powder and also magnetite nanoparticles. The obtained polymeric matrices were morphologically characterized, which showed 85-90% porosity, uniform pores distribution, high permeability and controlled degradation (19-30%) in 4 weeks depending upon the composition of formulations. Further, the polymeric macroporous formulations were tested for persistence of mosquitocidal activity against Culex quinquefasciatus larvae. Unformulated B. sphaericus ISPC-8 spores retained 54% of larvicidal activity after 7 days, which completely reduced after 35 days of treatment. However, the immobilized B. sphaericus spores in agarose-alginate formulations showed high larvicidal activity on day 7 and retained about 45% activity even after 35 days of treatments. Studies on UV-B and pH dependent inactivation of toxins and spore viability showed that these formulations were significantly protecting the spores as compared to the unformulated spores, which suggest its potential application for the mosquito control program.

  1. Microfabricated Passive Magnetic Bead separators

    DEFF Research Database (Denmark)

    Hansen, Mikkel Fougt; Lund-Olesen, Torsten; Smistrup, Kristian

    2006-01-01

    The use and manipulation of functionalized magnetic beads for bioanalysis in lab-on-a-chip systems is receiving growing interest. We have developed microfluidic systems with integrated magnetic structures for the capture and release of magnetic beads. The systems are fabricated in silicon by deep...... reactive ion etching combined with a number of metal deposition and etching steps followed by anodic bonding of a pyrex lid....

  2. Cellulose Insulation

    Science.gov (United States)

    1980-01-01

    Fire retardant cellulose insulation is produced by shredding old newspapers and treating them with a combination of chemicals. Insulating material is blown into walls and attics to form a fiber layer which blocks the flow of air. All-Weather Insulation's founders asked NASA/UK-TAP to help. They wanted to know what chemicals added to newspaper would produce an insulating material capable of meeting federal specifications. TAP researched the query and furnished extensive information. The information contributed to successful development of the product and helped launch a small business enterprise which is now growing rapidly.

  3. Development of Three-Dimensional Multicellular Tissue-Like Constructs for Mutational Analysis Using Macroporous Microcarriers

    Science.gov (United States)

    Jordan, Jacqueline A.; Fraga, Denise N.; Gonda, Steve R.

    2002-01-01

    A three-dimensional (3-D), tissue-like model was developed for the genotoxic assessment of space environment. In previous experiments, we found that culturing mammalian cells in a NASA-designed bioreactor, using Cytodex-3 beads as a scaffold, generated 3-D multicellular spheroids. In an effort to generate scaffold-free spheroids, we developed a new 3-D tissue-like model by coculturing fibroblast and epithelial cell in a NASA bioreactor using macroporous Cultispher-S(TradeMark) microcarriers. Big Blue(Registered Trademark) Rat 2(Lambda) fibroblasts, genetically engineered to contain multiple copies (>60 copies/cell) of the Lac I target gene, were cocultured with radio-sensitive human epithelial cells, H184F5. Over an 8-day period, samples were periodically examined by microscopy and histology to confirm cell attachment, growth, and viability. Immunohistochemistry and western analysis were used to evaluate the expression of specific cytoskeletal and adhesion proteins. Key cell culture parameters (glucose, pH, and lactate concentrations) were monitored daily. Controls were two-dimensional mono layers of fibroblast or epithelial cells cultured in T-flasks. Analysis of 3-D spheroids from the bioreactor suggests fibroblast cells attached to and completely covered the bead surface and inner channels by day 3 in the bioreactor. Treatment of the 3-day spheroids with dispase II dissolved the Cultisphers(TradeMark) and produced multicellular, bead-less constructs. Immunohistochemistry confirmed the presence of vi.mentin, cytokeratin and E-cadherin in treated spheroids. Examination of the dispase II treated spheroids with transmission electron microscopy (TEM) also showed the presence of desmosomes. These results suggest that the controlled enzymatic degradation of an artificial matrix in the low shear environment of the NASA-designed bioreactor can produce 3-D tissue-like spheroids. 2

  4. Macroporous synthetic hydroxyapatite bioceramics for bone substitute applications

    CSIR Research Space (South Africa)

    Thomas, ME

    1999-08-01

    Full Text Available An improved strategy is described for the manufacture of macroporous hydroxyapatite bioceramics for bone substitute applications. This is based on a modified fugitive phase technique, which allows production of relatively open, high-strength devices...

  5. Stable Aqueous Foams from Cellulose Nanocrystals and Methyl Cellulose.

    Science.gov (United States)

    Hu, Zhen; Xu, Richard; Cranston, Emily D; Pelton, Robert H

    2016-12-12

    The addition of cellulose nanocrystals (CNC) greatly enhanced the properties of methylcellulose (MC) stabilized aqueous foams. CNC addition decreased air bubble size, initial foam densities and drainage rates. Mixtures of 2 wt % CNC + 0.5 wt % MC gave the lowest density foams. This composition sits near the onset of nematic phase formation and also near the overlap concentration of methylcellulose. More than 94% of the added CNC particles remained in the foam phase, not leaving with the draining water. We propose that the nanoscale CNC particles bind to the larger MC coils both in solution and with MC at the air/water interface, forming weak gels that stabilize air bubbles. Wet CNC-MC foams were sufficiently robust to withstand high temperature (70 °C for 6 h) polymerization of water-soluble monomers giving macroporous CNC composite hydrogels based on acrylamide (AM), 2-hydroxyethyl methacrylate (HEMA), or polyethylene glycol diacrylate (PEGDA). At high temperatures, the MC was present as a fibrillar gel phase reinforced by CNC particles, explaining the very high foam stability. Finally, our CNC-MC foams are based on commercially available forms of CNC and MC, already approved for many applications. This is a "shovel-ready" technology.

  6. Preparative Purification of Liriodendrin from Sargentodoxa cuneata by Macroporous Resin

    OpenAIRE

    Di-Hua Li; Yan Wang; Yuan-Shan Lv; Jun-Hong Liu; Lei Yang; Shu-Kun Zhang; Yu-Zhen Zhuo

    2015-01-01

    The preparative purification of liriodendrin from Sargentodoxa cuneata using macroporous resin combined with crystallization process was evaluated. The properties of adsorption/desorption of liriodendrin on eight macroporous resins were investigated systematically. X-5 resin was selected as the most suitable medium for liriodendrin purification. The adsorption of liriodendrin on X-5 resin fitted well with the pseudo-second-order kinetic model and Langmuir isotherm model. Dynamic adsorption/de...

  7. Hierarchical Porous Polymer Beads Prepared by Polymerization-induced Phase Separation and Emulsion-template in a Microfluidic Device

    Institute of Scientific and Technical Information of China (English)

    Wei-cai Wang; Yan-xiong Pan; Kai Shi; Chao Peng; Xiang-ling Ji

    2014-01-01

    Porous polymer beads (PPBs) containing hierarchical bimodal pore structure with gigapores and meso-macropores were prepared by polymerization-induced phase separation (PIPS) and emulsion-template technique in a glass capillary microfluidic device (GCMD).Fabrication procedure involved the preparation of water-in-oil emulsion by emulsifying aqueous solution into the monomer solution that contains porogen.The emulsion was added into the GCMD to fabricate the (water-in-oil)-in-water double emulsion droplets.The flow rate of the carrier continuous phase strongly influenced the formation mechanism and size of droplets.Formation mechanism transformed from dripping to jetting and size of droplets decreased from 550 μm to 250 μm with the increase in flow rate of the carrier continuous phase.The prepared droplets were initiated for polymerization by on-line UV-irradiation to form PPBs.The meso-macropores in these beads were generated by PIPS because of the presence ofporogen and gigapores obtained from the emulsion-template.The pore morphology and pore size distribution of the PPBs were investigated extensively by scanning electron microscopy and mercury intrusion porosimetry (MIP).New pore morphology was formed at the edge of the beads different from traditional theory because of different osmolarities between the water phase of the emulsion and the cartier continuous phase.The morphology and proportion of bimodal pore structure can be tuned by changing the kind and amount of porogen.

  8. Glass-bead peen plating

    Science.gov (United States)

    Graves, J. R.

    1974-01-01

    Peen plating of aluminum, copper, and nickel powders was investigated. Only aluminum was plated successfully within the range of peen plating conditions studied. Optimum plating conditions for aluminum were found to be: (1) bead/powder mixture containing 25 to 35% powder by weight, (2) peening intensity of 0.007A as measured by Almen strip, and (3) glass impact bead diameter of at least 297 microns (0.0117 inches) for depositing-100 mesh aluminum powder. No extensive cleaning or substrate preparation is required beyond removing loose dirt or heavy oil.

  9. Cellulose metabolism in plants.

    Science.gov (United States)

    Hayashi, Takahisa; Yoshida, Kouki; Park, Yong Woo; Konishi, Teruko; Baba, Kei'ichi

    2005-01-01

    Many bacterial genomes contain a cellulose synthase operon together with a cellulase gene, indicating that cellulase is required for cellulose biosynthesis. In higher plants, there is evidence that cell growth is enhanced by the overexpression of cellulase and prevented by its suppression. Cellulase overexpression could modify cell walls not only by trimming off the paracrystalline sites of cellulose microfibrils, but also by releasing xyloglucan tethers between the microfibrils. Mutants for membrane-anchored cellulase (Korrigan) also show a typical phenotype of prevention of cellulose biosynthesis in tissues. All plant cellulases belong to family 9, which endohydrolyzes cellulose, but are not strong enough to cause the bulk degradation of cellulose microfibrils in a plant body. It is hypothesized that cellulase participates primarily in repairing or arranging cellulose microfibrils during cellulose biosynthesis in plants. A scheme for the roles of plant cellulose and cellulases is proposed.

  10. Wax beads as cushioning agents during the compression of coated diltiazem pellets.

    Science.gov (United States)

    Vergote, G J; Kiekens, F; Vervaet, C; Remon, J P

    2002-11-01

    Placebo particles were mixed with film-coated diltiazem pellets to evaluate them as cushioning agents during tabletting in order to protect the film coat from damage. The cushioning properties of alpha-lactose monohydrate granules, microcrystalline cellulose pellets and wax/starch beads were evaluated by comparing the dissolution profile of the coated pellets before and after compression (compression force 10 kN). Only the tablet formulations containing wax/starch beads provided protection to the film coat. However, the dissolution rate of tablets formulated with waxy maltodextrin/paraffinic wax placebo beads was too slow as the tablets did not disintegrate. Adding 50% (w/w) drum-dried corn starch/Explotab/paraffinic wax beads to the formulation was the optimal amount of cushioning beads to provide sufficient protection for the film coat and yield disintegrating tablets. Using a compression simulator, the effect of precompression force and compression time on the dissolution rate was found to be insignificant. The diametral crushing strength of tablets containing 50% (w/w) drum-dried corn starch/Explotab/paraffinic wax beads was about 25.0 N (+/-0.3 N), with a friability of 0.4% (+/-0.04%). This study demonstrates that adding deformable wax pellets minimizes the damage to film-coated pellets during compression.

  11. Calibration beads containing luminescent lanthanide ion complexes

    Science.gov (United States)

    The reliability of lanthanide luminescence measurements, by both flow cytometry and digital microscopy, will be enhanced by the availability of narrow-band emitting lanthanide calibration beads. These beads can also be used to characterize spectrographic instruments, including mi...

  12. Purification of total flavonoids from loquat leaves by macroporous resin and corresponding antioxidant capacity

    OpenAIRE

    Huang Suhua; Lin Biaosheng; Li Binbin; Tan Bi; Hong Yanping

    2017-01-01

    Flavonoids is one of the major active compounds in loquat leaves. In this study, the purification process of total flavonoids in loquat leaves by macroporous resin was researched and the antioxidant activity of total flavonoids was determined. The active compounds were extracted by 95% ethanol, and the total flavonoids was purified by macroporous resin. Comparing the static and dynamic adsorption and desorption characters of 6 macroporous resin, the best type of macroporous resin was determin...

  13. 3D multi-layered fibrous cellulose structure using an electrohydrodynamic process for tissue engineering.

    Science.gov (United States)

    Kim, Minseong; Kim, GeunHyung

    2015-11-01

    Micro/nanofibrous structures have been applied widely in various tissue-engineering applications because the topological structures are similar to the extracellular matrix (ECM), which encourages a high degree of cell adhesion and growth. However, it has been difficult to produce a three-dimensional (3D) fibrous structure using controllable macro-pores. Recently, cellulose has been considered a high-potential natural-origin biomaterial, but its use in 3D biomedical structures has been limited due to its narrow processing window. Here, we suggest a new 3D cellulose scaffold consisting of multi-layered struts made of submicron-sized entangled fibers that were fabricated using an electrohydrodynamic direct jet (EHDJ) process that is spin-printing. By optimizing processing conditions (electric field strength, cellulose feeding rate, and distance between nozzle and target), we can achieve a multi-layered cellulose structure consisting of the cylindrically entangled cellulose fibers. To compare the properties of the fabricated 3D cellulose structure, we used a PCL fibrous scaffold, which has a similar fibrous morphology and pore geometry, as a control. The physical and in vitro biocompatibilities of both fibrous scaffolds were assessed using human dermal fibroblasts, and the cellulose structure showed higher cell adhesion and metabolic activities compared with the control. These results suggest the EHDJ process to be an effective fabricating tool for tissue engineering and the cellulose scaffold has high potential as a tissue regenerative material.

  14. Molecularly imprinted macroporous monolithic materials for protein recognition

    Institute of Scientific and Technical Information of China (English)

    Qi Liang Deng; Yan Li Li; Li Hua Zhang; Yu Kui Zhang

    2011-01-01

    Synthetic materials that can specifically recognize proteins will find wide application in many fields. In this report, bovine serum albumin was chosen as the template protein. Acrylamide and N, N'-methylenebisacrylamide were employed as the functional and cross-linker monomers, respectively. Molecularly imprinted macroporous monolithic materials that can preferentially bind the template protein in an aqueous environment were prepared by combination of molecular imprinting technique and freezing/thawing preparation method. The resulted imprinted macroporous monolithic columns were evaluated by utilizing as stationary phase in high performance liquid chromatography and solid-phase extraction materials. The experimental results indicated that the imprinted macroporous monolithic column exhibited good recognition for template protein, as compared with the control protein (hemoglobin), whereas the non-imprinted polymer (prepared under the same conditions except without addition template protein) had no selective properties.

  15. Quantifying macropore recharge: Examples from a semi-arid area

    Science.gov (United States)

    Wood, W.W.; Rainwater, K.A.; Thompson, D.B.

    1997-01-01

    The purpose of this paper is to illustrate the significantly increased resolution of determining macropore recharge by combining physical, chemical, and isotopic methods of analysis. Techniques for quantifying macropore recharge were developed for both small-scale (1 to 10 km2) and regional-scale areas in and semi-arid areas. The Southern High Plains region of Texas and New Mexico was used as a representative field site to test these methods. Macropore recharge in small-scale areas is considered to be the difference between total recharge through floors of topographically dosed basins and interstitial recharge through the same area. On the regional scale, macropore recharge was considered to be the difference between regional average annual recharge and interstitial recharge measured in the unsaturated zone. Stable isotopic composition of ground water and precipitation was used us an independent estimate of macropore recharge on the regional scale. Results of this analysis suggest that in the Southern High Plains recharge flux through macropores is between 60 and 80 percent of the total 11 mm/y. Between 15 and 35 percent of the recharge occurs by interstitial recharge through the basin floors. Approximately 5 percent of the total recharge occurs as either interstitial or matrix recharge between the basin floors, representing approximately 95 percent of the area. The approach is applicable to other arid and semi-arid areas that focus rainfall into depressions or valleys.The purpose of this paper is to illustrate the significantly increased resolution of determining macropore recharge by combining physical, chemical, and isotopic methods of analysis. Techniques for quantifying macropore recharge were developed for both small-scale (1 to 10 km2) and regional-scale areas in arid and semi-arid areas. The Southern High Plains region of Texas and New Mexico was used as a representative field site to test these methods. Macropore recharge in small-scale areas is considered

  16. Developement of Spherical Polyurethane Beads

    Institute of Scientific and Technical Information of China (English)

    K. Maeda; H. Ohmori; H. Gyotoku

    2005-01-01

    @@ 1Results and Discussion We established a new method to produce the spherical polyurethane beads which have narrower distribution of particle size. This narrower distribution was achieved by the polyurethane prepolymer which contains ketimine as a blocked chain-extending agent. Firstly, the prepolymer is dispersed into the aqueous solution containing surfactant. Secondaly, water comes into the inside of prepolymer as oil phase. Thirdly, ketimine is hydrolyzed to amine, and amine reacts with prepolymer immediately to be polyurethane.Our spherical polyurethane beads are very suitable for automotive interior parts especially for instrument panel cover sheet producing under the slush molding method, because of good process ability, excellent durability to the sunlight and mechanical properties at low temperature. See Fig. 1 ,Fig. 2 and Fig. 3 (Page 820).

  17. Direct friction measurement in draw bead testing

    DEFF Research Database (Denmark)

    Olsson, David Dam; Bay, Niels; Andreasen, Jan Lasson

    2005-01-01

    The application of draw beads in sheet metal stamping ensures controlled drawing-in of flange parts. Lubrication conditions in draw beads are severe due to sliding under simultaneous bending. Based on the original draw bead test design by Nine [1] comprehensive studies of friction in draw beads...... have been reported in literature. A major drawback in all these studies is that friction is not directly measured, but requires repeated measurements of the drawing force with and without relative sliding between the draw beads and the sheet material. This implies two tests with a fixed draw bead tool...... and a freely rotating tool respectively, an approach, which inevitably implies large uncertainties due to scatter in the experimental conditions. In order to avoid this problem a new draw bead test is proposed by the authors measuring the friction force acting on the tool radius directly by a build...

  18. 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.

  19. Emulsion-templated macroporous carbons synthesized by hydrothermal carbonization and their application for the enzymatic oxidation of glucose.

    Science.gov (United States)

    Brun, Nicolas; Edembe, Lise; Gounel, Sébastien; Mano, Nicolas; Titirici, Magdalena M

    2013-04-01

    Carbon-based monoliths have been designed using a simple synthetic pathway based on using high internal phase emulsion (HIPE) as a soft template to confine the polymerization and hydrothermal carbonization of saccharide derivatives (furfural) and phenolic compounds (phloroglucinol). Monosaccharides can be isolated from the cellulosic fraction of lignocellulosic biomass and phloroglucinol can be extracted from the bark of fruit trees; however, this approach constitutes an interesting sustainable synthetic route. The macroscopic characteristics can be easily modulated; a high macroporosity and total pore volume of up to 98 % and 18 cm(3)g(-1) have been obtained, respectively. After further thermal treatment under inert atmosphere, the as-synthesized macroporous carbonized HIPEs (carbo-HIPEs) have shaping capabilities relating to interesting mechanical properties as well as a high electrical conductivity of up to 300 Sm(-1) . These conductive foams exhibit a hierarchical structure associated with the presence of both meso- and micropores that exhibit specific Brunauer-Emmett-Teller (BET) surface areas and DFT total pore volumes up to 730 m(2)g(-1) and 0.313 cm(3)g(-1) , respectively. Because of their attractive structural characteristics and intrinsic properties, these macroporous monoliths have been incorporated as a proof of principle within electrochemical devices as modified thin carbon disc electrodes. A promising two-fold improvement in the catalytic current is observed for the electrooxidation of glucose after the immobilization of a glucose oxidase-based biocatalytic mixture onto the carbo-HIPE electrodes compared to that observed if using commercial glassy carbon electrodes.

  20. Fabrication and Characteristics of Macroporous TiO2 Photocatalyst

    Directory of Open Access Journals (Sweden)

    Guiyun Yi

    2014-01-01

    Full Text Available Macroporous TiO2 photocatalyst was synthesized by a facile nanocasting method using polystyrene (PS spherical particles as the hard template. The synthesized photocatalyst was characterized by transmission electron microscope (TEM, scanning electron microscopy (SEM, thermogravimetry-differential thermogravimetry (TG-DTG, X-ray diffraction (XRD, and N2-sorption. TEM, SEM, and XRD characterizations confirmed that the macroporous TiO2 photocatalyst is composed of anatase phase. The high specific surface area of 87.85 m2/g can be achieved according to the N2-sorption analysis. Rhodamine B (RhB was chosen as probe molecule to evaluate the photocatalytic activity of the TiO2 catalysts. Compared with the TiO2 materials synthesized in the absence of PS spherical template, the macroporous TiO2 photocatalyst sintered at 500°C exhibits much higher activity on the degradation of RhB under the UV irradiation, which can be assigned to the well-structured macroporosity. The macroporous TiO2 material presents great potential in the fields of environmental remediation and energy conversion and storage.

  1. Dye tracer infiltration technique to investigate macropore flow paths in Maka Mountain, Yunnan Province, China

    Institute of Scientific and Technical Information of China (English)

    张家明; 徐则民

    2016-01-01

    In order to investigate the differences of macropores vertical distribution under different surface plants, and to assess the influences of root systems, organic matter and texture on macropore flow paths, two dye tracer infiltration experiments were performed in slopes under two different plants (Campylotropis polyantha (Franch.) Schindl vs.Cynodon dactylon(Linn.) Pers). Dye tracer infiltration experiments with field observations and measurements of soil properties were combined. Results show that the discrepancy in macropores distribution between two slopes under different plants is significant. Root systems have significant effects on macropore flow paths distribution and the effect become more pronounced as the diameter of roots become larger. Organic matter and stone are important factors to affect macropores distribution. Root-soil interface, inter-aggregate macropore and stone-soil interface are important macropore flow paths in well vegetated slopes.

  2. Cellulose Fibre-Reinforced Biofoam for Structural Applications

    Directory of Open Access Journals (Sweden)

    Jasmina Obradovic

    2017-06-01

    Full Text Available Traditionally, polymers and macromolecular components used in the foam industry are mostly derived from petroleum. The current transition to a bio-economy creates demand for the use of more renewable feedstocks. Soybean oil is a vegetable oil, composed mainly of triglycerides, that is suitable material for foam production. In this study, acrylated epoxidized soybean oil and variable amounts of cellulose fibres were used in the production of bio-based foam. The developed macroporous bio-based architectures were characterised by several techniques, including porosity measurements, nanoindentation testing, scanning electron microscopy, and thermogravimetric analysis. It was found that the introduction of cellulose fibres during the foaming process was necessary to create the three-dimensional polymer foams. Using cellulose fibres has potential as a foam stabiliser because it obstructs the drainage of liquid from the film region in these gas-oil interfaces while simultaneously acting as a reinforcing agent in the polymer foam. The resulting foams possessed a porosity of approximately 56%, and the incorporation of cellulose fibres did not affect thermal behaviour. Scanning electron micrographs showed randomly oriented pores with irregular shapes and non-uniform pore size throughout the samples.

  3. Beads, beaded-fibres and fibres: Tailoring the morphology of poly(caprolactone) using pressurised gyration.

    Science.gov (United States)

    Hong, Xianze; Edirisinghe, Mohan; Mahalingam, Suntharavathanan

    2016-12-01

    This work focuses on forming bead on string poly(caprolactone) (PCL) by using gyration under pressure. The fibre morphology of bead on string is an interesting feature that falls between bead-free fibres and droplets, and it could be effectively controlled by the rheological properties of spinning dopes and the major processing parameters of the pressurised gyration system which are working pressure and rotating speed. Bead products were not always spherical in shape and tended to be more elliptical, therefore both their width and length were measured. The average bead width and length produced spanned a range 145-660μm and 140-1060μm, respectively. The average distance between two adjacent beads (i.e. inter-bead distance) and the bead size (width and length) are shown to be a function of processing parameters and polymer concentration. An interesting morphology i.e. beads with short fibre was observed when using a high polymer concentration. Bead on string structure agglomeration was promoted by a low polymer concentration. Formation of droplets or agglomerated bead on string is promoted below 5wt% polymer concentration, and beads with short fibre were present in the microstructure beyond a polymer concentration of 20wt%. Copyright © 2016. Published by Elsevier B.V.

  4. Salmonella biofilm formation on Aspergillus niger involves cellulose--chitin interactions.

    Directory of Open Access Journals (Sweden)

    Maria T Brandl

    Full Text Available Salmonella cycles between host and nonhost environments, where it can become an active member of complex microbial communities. The role of fungi in the environmental adaptation of enteric pathogens remains relatively unexplored. We have discovered that S. enterica Typhimurium rapidly attaches to and forms biofilms on the hyphae of the common fungus, Aspergillus niger. Several Salmonella enterica serovars displayed a similar interaction, whereas other bacterial species were unable to bind to the fungus. Bacterial attachment to chitin, a major constituent of fungal cell walls, mirrored this specificity. Pre-incubation of S. Typhimurium with N-acetylglucosamine, the monomeric component of chitin, reduced binding to chitin beads by as much as 727-fold and inhibited attachment to A. niger hyphae considerably. A cellulose-deficient mutant of S. Typhimurium failed to attach to chitin beads and to the fungus. Complementation of this mutant with the cellulose operon restored binding to chitin beads to 79% of that of the parental strain and allowed for attachment and biofilm formation on A. niger, indicating that cellulose is involved in bacterial attachment to the fungus via the chitin component of its cell wall. In contrast to cellulose, S. Typhimurium curli fimbriae were not required for attachment and biofilm development on the hyphae but were critical for its stability. Our results suggest that cellulose-chitin interactions are required for the production of mixed Salmonella-A. niger biofilms, and support the hypothesis that encounters with chitinaceous alternate hosts may contribute to the ecological success of human pathogens.

  5. Expanded polylactide bead foaming - A new technology

    Science.gov (United States)

    Nofar, M.; Ameli, A.; Park, C. B.

    2015-05-01

    Bead foaming technology with double crystal melting peak structure has been recognized as a promising method to produce low-density foams with complex geometries. During the molding stage of the bead foams, the double peak structure generates a strong bead-to-bead sintering and maintains the overall foam structure. During recent years, polylactide (PLA) bead foaming has been of the great interest of researchers due to its origin from renewable resources and biodegradability. However, due to the PLA's low melt strength and slow crystallization kinetics, the attempts have been limited to the manufacturing methods used for expanded polystyrene. In this study, for the first time, we developed microcellular PLA bead foams with double crystal melting peak structure. Microcellular PLA bead foams were produced with expansion ratios and average cell sizes ranging from 3 to 30-times and 350 nm to 15 µm, respectively. The generated high melting temperature crystals during the saturation significantly affected the expansion ratio and cell density of the PLA bead foams by enhancing the PLA's poor melt strength and promoting heterogeneous cell nucleation around the crystals.

  6. Ultrasonic Characterization of Glass Beads

    Science.gov (United States)

    Lassila, I.; Siiriä, S.; Gates, F. K.; Hæggström, E.

    2008-02-01

    We report on the progress in developing a method for an in-line granule size measurement using ultrasonic through transmission method. The knowledge of granule size is important in the production of pharmaceutical dosage forms where the current optical and rheological methods have limitations such as fouling of the optical windows. The phase velocity of a wave propagated through interstitial air between glass balls of 1, 2 and 10 mm in diameter was 254±5 m/s, 261±3 m/s and 320±9 m/s, respectively. The power spectral density of the received signals showed that high frequencies were attenuated more in case of smaller beads due to increased scattering.

  7. Preparative Purification of Liriodendrin from Sargentodoxa cuneata by Macroporous Resin.

    Science.gov (United States)

    Li, Di-Hua; Wang, Yan; Lv, Yuan-Shan; Liu, Jun-Hong; Yang, Lei; Zhang, Shu-Kun; Zhuo, Yu-Zhen

    2015-01-01

    The preparative purification of liriodendrin from Sargentodoxa cuneata using macroporous resin combined with crystallization process was evaluated. The properties of adsorption/desorption of liriodendrin on eight macroporous resins were investigated systematically. X-5 resin was selected as the most suitable medium for liriodendrin purification. The adsorption of liriodendrin on X-5 resin fitted well with the pseudo-second-order kinetic model and Langmuir isotherm model. Dynamic adsorption/desorption tests were performed using a glass column packed with X-5 resin to optimize the separation process of liriodendrin. After one treatment with X-5 resin, the content of liriodendrin in the product was increased 48.73-fold, from 0.85% to 41.42%, with a recovery yield of 88.9%. 97.48% liriodendrin was obtained by further crystallization and determined by HPLC. The purified product possessed strong antioxidant activity. In conclusion, purification of liriodendrin might expend its further pharmacological researches and further applications in pharmacy.

  8. Kinetic and thermodynamic studies of sulforaphane adsorption on macroporous resin.

    Science.gov (United States)

    Yuanfeng, Wu; Lei, Zhang; Jianwei, Mao; Shiwang, Liu; Jun, Huang; Yuru, You; Lehe, Mei

    2016-08-15

    The adsorption equilibrium, kinetic and thermodynamic of sulforaphane (SF) adsorption onto macroporous resin in aqueous phase were studied. The SP850 resin was screened as the appropriate resin for SF purification. From the equilibrium studies, the Redlich-Peterson model was found to be the best for description of the adsorption behavior of SF onto SP850 resin, followed by the Freundlich model and the Langmuir model. Batch equilibrium experiments demonstrated that, in the examined temperature range, the equilibrium adsorption capacity of SP850 resin decreased with increasing adsorption temperature. Thermodynamics studies indicated that the adsorption of SF was a physical, exothermic, and spontaneous process. The adsorption kinetics revealed that the pseudo-second-order kinetic model was suitable to characterize the kinetics of adsorption of SF onto SP850. Finally, the intra-particle diffusion model demonstrated that SF diffused quickly into macropores, and that diffusion slowed down in the meso- and micropores.

  9. Cellulose Degradation by Cellulose-Clearing and Non-Cellulose-Clearing Brown-Rot Fungi

    OpenAIRE

    Highley, Terry L.

    1980-01-01

    Cellulose degradation by four cellulose-clearing brown-rot fungi in the Coniophoraceae—Coniophora prasinoides, C. puteana, Leucogyrophana arizonica, and L. olivascens—is compared with that of a non-cellulose-clearing brown-rot fungus, Poria placenta. The cellulose- and the non-cellulose-clearing brown-rot fungi apparently employ similar mechanisms to depolymerize cellulose; most likely a nonenzymatic mechanism is involved.

  10. Cellulose binding domain proteins

    Science.gov (United States)

    Shoseyov, Oded; Shpiegl, Itai; Goldstein, Marc; Doi, Roy

    1998-01-01

    A cellulose binding domain (CBD) having a high affinity for crystalline cellulose and chitin is disclosed, along with methods for the molecular cloning and recombinant production thereof. Fusion products comprising the CBD and a second protein are likewise described. A wide range of applications are contemplated for both the CBD and the fusion products, including drug delivery, affinity separations, and diagnostic techniques.

  11. Macroporous bioceramics: a remarkable material for bone regeneration.

    Science.gov (United States)

    Lew, Kien-Seng; Othman, Radzali; Ishikawa, Kunio; Yeoh, Fei-Yee

    2012-09-01

    This review summarises the major developments of macroporous bioceramics used mainly for repairing bone defects. Porous bioceramics have been receiving attention ever since their larger surface area was reported to be beneficial for the formation of more rigid bonds with host tissues. The study of porous bioceramics is important to overcome the less favourable bonds formed between dense bioceramics and host tissues, especially in healing bone defects. Macroporous bioceramics, which have been studied extensively, include hydroxyapatite, tricalcium phosphate, alumina, and zirconia. The pore size and interconnections both have significant effects on the growth rate of bone tissues. The optimum pore size of hydroxyapatite scaffolds for bone growth was found to be 300 µm. The existence of interconnections between pores is critical during the initial stage of tissue ingrowth on porous hydroxyapatite scaffolds. Furthermore, pore formation on β-tricalcium phosphate scaffolds also allowed the impregnation of growth factors and cells to improve bone tissues growth significantly. The formation of vascularised tissues was observed on macroporous alumina but did not take place in the case of dense alumina due to its bioinert nature. A macroporous alumina coating on scaffolds was able to improve the overall mechanical properties, and it enabled the impregnation of bioactive materials that could increase the bone growth rate. Despite the bioinertness of zirconia, porous zirconia was useful in designing scaffolds with superior mechanical properties after being coated with bioactive materials. The pores in zirconia were believed to improve the bone growth on the coated system. In summary, although the formation of pores in bioceramics may adversely affect mechanical properties, the advantages provided by the pores are crucial in repairing bone defects.

  12. Ordered coalescence of nanocrystals: a path to strong macroporous nanoceramics

    Energy Technology Data Exchange (ETDEWEB)

    Shen Zhijian; Xiong Yan [Berzelii Center EXSELENT for Porous Materials and Department of Materials and Environmental Chemistry, Arrhenius Laboratory, Stockholm University, Stockholm S-106 91 (Sweden); Hoeche, Thomas [Leibniz-Institut fuer Oberflaechenmodifizierung e.V., Permoserstrasse 15, Leipzig D-04318 (Germany); Salamon, David [Membrane Technology Group, University of Twente, PO Box 217, 7500 AE Enschede (Netherlands); Fu Zhengyi [State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Wuhan 430070 (China); Belova, Lyubov, E-mail: shen@mmk.su.se [Department of Materials Science and Engineering, Royal Institute of Technology, Stockholm S-100 44 (Sweden)

    2010-05-21

    A versatile approach for integrating two apparently conflicting physical properties, high porosity and high mechanical strength, in polycrystalline bulks is established and demonstrated for the case of alumina ceramics. Macroporous alumina nanoceramics are synthesized by stimulating coalescence-mediated necking, which enables the formation of strong crystallographically coherent necks between adjacent grains. The work places a general emphasis on manipulating crystal growth on the nanoscale and on preparing highly porous polycrystalline bulk ceramics with improved mechanical rigidity.

  13. THE SYNTHESIS OF MACROPOROUS CROSSLINKED POLYSTYRENE AMIDOPHOSPHONIC ACID

    Institute of Scientific and Technical Information of China (English)

    HE Binlin; WANG Linfu; CHEN Weizhu

    1984-01-01

    A series of macromolecular copolymers of styrene and divinyl-benzene were prepared in the presence of iso-octanol or 2-ethyl butyl alcohol. The factors which affected the physical structures of the copolymer were discussed. The macroporous amido-phosphonic acid resin was obtained after the acetylation, phosphonylation and amination of the crosslinked polystyrene. The factors which affected each reaction were studied and the change of physical structures of the copolymer were discussed.

  14. Macropore-mesopore model of water flow through aggregated porous media

    Energy Technology Data Exchange (ETDEWEB)

    Fong, L.; Appelbaum, H.R.

    1980-12-01

    A combined, one-dimensional, macropore-mesopore, hydrologic model was developed for simulating water flow through soils for analysis of data related to water and chemical flow in soils. Flows within the macroporous system as well as interactive flows between macroporous and mesoporous systems were modeled. Computer subroutines were written and incorporated into the existing one-dimensional Terrestrial Ecosystem Hydrologic Model (TEHM) developed at ORNL. Simulation showed that macropore flow effects are important during heavy precipitation and are more significant in soils of comparatively low hydraulic conductivity (5 to 10 cm/d). Increased drainage and decreased lateral flow result from the addition of the macropore model. The effect was more pronounced in soils of large macroporosity. Preliminary results indicate that the model is insensitive to geometrical properties of macropores.

  15. Porous Spherical Cellulose Composites Coated by Aluminum (Ⅲ) Oxide and Silicone: Preparation,Characterization and Adsorption Behavior

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Porous spherical cellulose composite (PSCA) coated by aluminum (Ⅲ) oxide was prepared andmodified by organosilicone. SEM images of the surface morphology of the bead cellulose shows that it hasspherical shape and abundant porous structure on its surface. The mapping images of aluminum and silicon ofthe composite (PSCAS) present aluminum( Ⅲ ) oxide and silicone are uniformly dispersed on the surface. Theadsorption behavior of PSCAS toward metal ions was determined.

  16. Taste masking of ofloxacin and formation of interpenetrating polymer network beads for sustained release

    Directory of Open Access Journals (Sweden)

    A. Michael Rajesh

    2017-08-01

    Full Text Available The objective of this study was to carry out taste masking of ofloxacin (Ofl by ion exchange resins (IERs followed by sustained release of Ofl by forming interpenetrating polymer network (IPN beads. Drug-resin complexes (DRCs with three different ratios of Ofl to IERs (1:1, 1:2, 1:4 were prepared by batch method and investigated for in vivo and in vitro taste masking. DRC of methacrylic acid-divinyl benzene (MD resin and Ofl prepared at a ratio of 1:4 was used to form IPN beads. IPN beads of MD 1:4 were prepared by following the ionic cross-linking method using sodium carboxymethyl xanthan gum (SCMXG and SCMXG-sodium carboxymethyl cellulose (SCMXG-SCMC. IPN beads were characterized with FT-IR and further studied on sustained release of Ofl at different pH. In vivo taste masking carried out by human volunteers showed that MD 1:4 significantly reduced the bitterness of Ofl. Characterization studies such as FT-IR, DSC, P-XRD and taste masking showed that complex formation took place between drug and resin. In vitro study at gastric pH showed complete release of drug from MD 1:4 within 30 min whereas IPN beads took 5 h at gastric pH and 10 h at salivary pH for the complete release of drug. As the crosslinking increased the release kinetics changed into non-Fickian diffusion to zero-order release mechanism. MD 1:4 showed better performance for the taste masking of Ofl and IPNs beads prepared from it were found useful for the sustained release of Ofl at both the pH, indicating a versatile drug delivery system.

  17. [Sizes of soil macropores and related main affecting factors on a vegetated basalt slope].

    Science.gov (United States)

    Guan, Qi; Xu, Ze-Min; Tian, Lin

    2013-10-01

    The landslide on vegetated slopes caused by extreme weather has being increased steadily, and the preferential flow in soil macropores plays an important role in the landslide. By using water breakthrough curve and Poiseuille equation, this paper estimated the radius range, amount, and average volume of soil macropores on a vegetated basalt slope of Maka Mountain, Southwest China, and analyzed the distribution of the soil macropores and the main affecting factors. In the study area, the radius of soil macropores ranged from 0.3 to 1.8 mm, mainly between 0.5 and 1.2 mm. The large-radius macropores (1.4-1.8 mm) were lesser, while the small-radius macropores (< 1.4 mm) were more. With the development of soil profile, soil macropores were more in upper layers and lesser in deeper layers. The average volume of the macropores contributed 84.7% to the variance of steady effluent rate. Among the factors affecting the average volume of the large macropores, vegetations root mass had a linear relationship, with the correlation coefficient being 0.70, and soil organic matter content also had a linear relationship, with the correlation coefficient being 0.64.

  18. [Macropore characteristics and its relationships with the preferential flow in broadleaved forest soils of Simian Mountains].

    Science.gov (United States)

    Wang, Wei; Zhang, Hong-jiang; Cheng, Jin-hua; Wu, Yu-he; Du, Shi-cai; Wang, Ran

    2010-05-01

    Brilliant blue dyeing and water breakthrough curve were applied to study the number and distribution of macropores and their relations to the preferential flow in typical sub-tropic broad-leaved forest soils of Simian Mountains. The radii of the macropores were mainly between 0. 3 and 3.0 mm, with the macroporosities in the range of 6.3% to 10.5%, and the macropores were always distributed in aggregation with increasing soil depth. The number of the macropores in each radius interval of dye-stained areas was tenfold increase than that of blank areas. The number of the macropores with radius larger than 0.3 mm, especially larger than 1.5 mm, was the most important factor affecting the occurrence of preferential flow. Significant correlations were found between the number of macropores and the water steady effluent volume, with the highest correlation coefficients of 0.842 and 0.879 for the radii intervals of 0.7-1.5 mm and 1.5-3.0 mm, respectively. Macro-pore continuity in dye-stained areas was better than that in blank areas, especially in the radius interval of 1.5-3.0 mm, with the biggest difference of 78.31%. In dye-stained areas, the number of macropores decreased gradually with soil depth. The filler-like distribution of macropores formed an effective water pressure gradient, which resulted in the preferential transport of water.

  19. Bead mediated separation of microparticles in droplets

    Science.gov (United States)

    Sung, Ki-Joo; Lin, Xiaoxia Nina; Burns, Mark A.

    2017-01-01

    Exchange of components such as particles and cells in droplets is important and highly desired in droplet microfluidic assays, and many current technologies use electrical or magnetic fields to accomplish this process. Bead-based microfluidic techniques offer an alternative approach that uses the bead’s solid surface to immobilize targets like particles or biological material. In this paper, we demonstrate a bead-based technique for exchanging droplet content by separating fluorescent microparticles in a microfluidic device. The device uses posts to filter surface-functionalized beads from a droplet and re-capture the filtered beads in a new droplet. With post spacing of 7 μm, beads above 10 μm had 100% capture efficiency. We demonstrate the efficacy of this system using targeted particles that bind onto the functionalized beads and are, therefore, transferred from one solution to another in the device. Binding capacity tests performed in the bulk phase showed an average binding capacity of 5 particles to each bead. The microfluidic device successfully separated the targeted particles from the non-targeted particles with up to 98% purity and 100% yield. PMID:28282412

  20. Ordered macroporous bimetallic nanostructures: design, characterization, and applications.

    Science.gov (United States)

    Lu, Lehui; Eychmüller, Alexander

    2008-02-01

    Ordered porous metal nanomaterials have current and future potential applications, for example, as catalysts, as photonic crystals, as sensors, as porous electrodes, as substrates for surface-enhanced Raman scattering (SERS), in separation technology, and in other emerging nanotechnologies. Methods for creating such materials are commonly characterized as "templating", a technique that involves first the creation of a sacrificial template with a specific porous structure, followed by the filling of these pores with desired metal materials and finally the removal of the starting template, leaving behind a metal replica of the original template. From the viewpoint of practical applications, ordered metal nanostructures with hierarchical porosity, namely, macropores in combination with micropores or mesopores, are of particular interest because macropores allow large guest molecules to access and an efficient mass transport through the porous structures is enabled while the micropores or mesopores enhance the selectivity and the surface area of the metal nanostructures. For this objective, colloidal crystals (or artificial opals) consisting of three-dimensional (3D) long-range ordered arrays of silica or polymer microspheres are ideal starting templates. However, with respect to the colloidal crystal templating strategies for production of ordered porous metal nanostructures, there are two challenging questions for materials scientists: (1) how to uniformly and controllably fill the interstitial space of the colloidal crystal templates and (2) how to generate ordered composite metal nanostructures with hierarchical porosity. This Account reports on recent work in the development and applications of ordered macroporous bimetallic nanostructures in our laboratories. A series of strategies have been explored to address the challenges in colloidal crystal template techniques. By rationally tailoring experimental parameters, we could readily and selectively design

  1. 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

    2016-06-05

    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 100 nm 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 50 nm latex beads and Hepatitis C Virus, respectively.

  2. Hazy Transparent Cellulose Nanopaper

    Science.gov (United States)

    Hsieh, Ming-Chun; Koga, Hirotaka; Suganuma, Katsuaki; Nogi, Masaya

    2017-01-01

    The aim of this study is to clarify light scattering mechanism of hazy transparent cellulose nanopaper. Clear optical transparent nanopaper consists of 3–15 nm wide cellulose nanofibers, which are obtained by the full nanofibrillation of pulp fibers. At the clear transparent nanopaper with 40 μm thickness, their total transmittance are 89.3–91.5% and haze values are 4.9–11.7%. When the pulp fibers are subjected to weak nanofibrillation, hazy transparent nanopapers are obtained. The hazy transparent nanopaper consists of cellulose nanofibers and some microsized cellulose fibers. At the hazy transparent nanopaper with 40 μm thickness, their total transmittance were constant at 88.6–92.1% but their haze value were 27.3–86.7%. Cellulose nanofibers are solid cylinders, whereas the pulp fibers are hollow cylinders. The hollow shape is retained in the microsized cellulose fibers, but they are compressed flat inside the nanopaper. This compressed cavity causes light scattering by the refractive index difference between air and cellulose. As a result, the nanopaper shows a hazy transparent appearance and exhibits a high thermal durability (295–305 °C), and low thermal expansion (8.5–10.6 ppm/K) because of their high density (1.29–1.55 g/cm3) and crystallinity (73–80%).

  3. 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.

  4. Acupressure Bead in the Eustachian Tube.

    Science.gov (United States)

    Igarashi, Kazunori; Matsumoto, Yu; Kakigi, Akinobu

    2015-08-01

    In this article, we aim to enlighten practitioners and patients involved with acupressure beads and to contribute to their safer use by reporting a unique case of insidious intrusion of an acupressure bead into the eustachian tube. A metallic object was found in the eustachian tube of a patient while conducting a magnetic resonance imaging (MRI) examination. The object was later confirmed to be an auricular acupressure bead, and was successfully removed by performing a tympanoplasty and a canal wall down mastoidectomy. The bead was assumed to have passed through an existing perforation of the tympanic membrane. According to previously published literature, tympanic membrane perforations exist in ∼1% of the population. Therefore, middle-ear foreign bodies are relatively common occurrences for otolaryngologists. However, metallic objects such as acupressure beads are especially important in the sense that they can cause severe burns during MRI. To avoid potential complications, acupressure-bead practitioners should be aware of the possibility that intrusions through the tympanic membrane could go unnoticed.

  5. Mechanically robust, rapidly actuating, and biologically functionalized macroporous poly(N-isopropylacrylamide)/silk hybrid hydrogels.

    Science.gov (United States)

    Gil, Eun Seok; Park, Sang-Hyug; Tien, Lee W; Trimmer, Barry; Hudson, Samuel M; Kaplan, David L

    2010-10-05

    A route toward mechanically robust, rapidly actuating, and biologically functionalized polymeric actuators using macroporous soft materials is described. The materials were prepared by combining silk protein and a synthetic polymer (poly(N-isopropylacrylamide) (PNIAPPm)) to form interpenetrating network materials and macroporous structures by freeze-drying, with hundreds of micrometer diameter pores and exploiting the features of both polymers related to dynamic materials and structures. The chemically cross-linked PNIPAAm networks provided stimuli-responsive features, while the silk interpenetrating network formed by inducing protein β-sheet crystallinity in situ for physical cross-links provided material robustness, improved expansion force, and enzymatic degradability. The macroporous hybrid hydrogels showed enhanced thermal-responsive properties in comparison to pure PNIPAAm hydrogels, nonporous silk/PNIPAAm hybrid hydrogels, and previously reported macroporous PNIPAAm hydrogels. These new systems reach near equilibrium sizes in shrunken/swollen states in less than 1 min, with the structural features providing improved actuation rates and stable oscillatory properties due to the macroporous transport and the mechanically robust silk network. Confocal images of the hydrated hydrogels around the lower critical solution temperature (LCST) revealed macropores that could be used to track changes in the real time morphology upon thermal stimulus. The material system transformed from a macroporous to a nonporous structure upon enzymatic degradation. To extend the utility of the system, an affinity platform for a switchable or tunable system was developed by immobilizing biotin and avidin on the macropore surfaces.

  6. Direct access to macroporous chromium nitride and chromium titanium nitride with inverse opal structure.

    Science.gov (United States)

    Zhao, Weitian; DiSalvo, Francis J

    2015-03-21

    We report a facile synthesis of single-phase, nanocrystalline macroporous chromium nitride and chromium titanium nitride with an inverse opal morphology. The material is characterized using XRD, SEM, HR-TEM/STEM, TGA and XPS. Interconversion of macroporous CrN to Cr2O3 and back to CrN while retaining the inverse opal morphology is also demonstrated.

  7. Highly Ordered TiO2 Macropore Arrays as Transparent Photocatalysts

    OpenAIRE

    Yuan Dong; Junfeng Chao; Zhong Xie; Xin Xu; Zhuoran Wang; Di Chen

    2012-01-01

    Highly ordered transparent TiO2 macropore arrays were synthesized via a simple glass-clamping method at room temperature. The as-synthesized TiO2 macropore arrays show high transmittance in the visible light region and can be used as transparent photocatalysts for degradation of organic dyes.

  8. Artificial macropores attract crop roots and enhance plant productivity on compacted soils.

    Science.gov (United States)

    Colombi, Tino; Braun, Serge; Keller, Thomas; Walter, Achim

    2017-01-01

    The structure of compacted soils is characterised by decreased (macro-)porosity, which leads to increased mechanical impedance and decreased fluid transport rates, resulting in reduced root growth and crop productivity. Particularly in soils with high mechanical impedance, macropores can be used by roots as pathways of least resistance. This study investigated how different soil physical states relate to whole plant growth and whether roots grow towards spots with favourable soil physical conditions. Experiments were conducted under controlled and field conditions. Soybean (Glycine max L.), wheat (Triticum aestivum L.) and maize (Zea mays L.) were grown on uncompacted soil, compacted soil and compacted soil with artificial macropores. The interactions between roots and artificial macropores were quantified using X-ray computed tomography. Active growth of roots towards artificial macropores was observed for all three species. Roots grew either into macropores (predominantly in maize) or crossed them (predominantly in wheat). The presence of artificial macropores in compacted soil enabled all three species to compensate for decreased early vigour at later developmental stages. These results show that roots sense their physical environment, enabling them to grow towards spots with favourable soil conditions. The different kinds of root-macropore interaction indicated that macropores serve as a path of least resistance and a source of oxygen, both resulting in increased crop productivity on compacted soils. Copyright © 2016 Elsevier B.V. All rights reserved.

  9. ADSORPTION OF PHENYLACETIC ACID ON MACROPOROUS POLYMERIC ADSORBENTS

    Institute of Scientific and Technical Information of China (English)

    PANBingcai; CHENJinlong; 等

    2002-01-01

    Several macroporous polymeric adsorbents(NDA-999,XAD-8,X-5 and XAD-2)were emplyed in the study to adsorb phenylacetic acid from aqueous solution.Effect of salt and ambient temperature on adsorption was studied using NDA-999 adsorbent and the adsorption process conforms to Freundlich′s model reasonably.Adsorption dynamics were conducted in batch experiments in order to make clear the mechanism of adsorption process.It is proved that the squared driving force mass transfer model can be adopted to elucidate the process.The treatment process of industrial wastewater containing high strength of phenylacetic acid was proposed for cleaner production of phenylacetic acid.

  10. ADSORPTION OF PHENYLACETIC ACID ON MACROPOROUS POLYMERIC ADSORBENTS

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Several macroporous polymeric adsorbents (NDA-999, XAD-8, X-5 and XAD-2) wereemployed in the study to adsorb phenylacetic acid from aqueous solution. Effect of salt and ambienttemperature on adsorption was studied using NDA-999 adsorbent and the adsorption processconforms to Freundlich's model reasonably. Adsorption dynamics were conducted in batchexperiments in order to make clear the mechanism of adsorption process. It is proved that thesquared driving force mass transfer model can be adopted to elucidate the process. The treatmentprocess of industrial wastewater containing high strength of phenylacetic acid was proposed forcleaner production of phenylacetic acid.

  11. Influence of Water on the Structure and Dielectric Properties of the Microcrystalline and Nano-Cellulose

    Science.gov (United States)

    Kovalov, Kostiantyn M.; Alekseev, Olexander M.; Lazarenko, Maxim M.; Zabashta, Yu F.; Grabovskii, Yurii E.; Tkachov, Sergii Yu

    2017-07-01

    Influence of water in the different states on a structure and dielectric properties of microcrystalline cellulose were studied by of X-ray, thermogravimetry, and dielectric spectroscopy. At research of microcrystalline cellulose (MCC) with different content of water, it is shown that the molecules of water are located in the macropores of MCC and in multimolecular hydrated layers. It is shown that at the increase of concentration of water in a hydrated shell, the reorganization of molecules of cellulose in the surface of crystallites takes place, and as a result, their transversal size and crystallinity increase. It is shown that during the concentration of water, more than 13% in a continuous hydrated shell of crystallites appears. Temperature dependences of actual and imaginary parts of complex dielectric permittivity were studied in the interval of temperatures [-180 ÷ 120] °C on frequencies of f = 5, 10, 20, and 50 kHz. A low-temperature relaxation process and high-temperature transition were observed. Low-temperature relaxation process which is related to transition of surface methylol groups of molecules of cellulose conformation from tg to tt is shifted toward low temperatures at the increase of concentration of water in microcrystalline cellulose.

  12. Preferential flow in macroporous swelling soil with internal catchment: model development and applications

    Science.gov (United States)

    Greco, Roberto

    2002-12-01

    A new model of infiltration in swelling and shrinking clay soil was developed. The model consisted of two flow domains: soil matrix, with flow modelled by means of Darcy equation, and macropores; the latter was divided in turn into two sub-domains: shrinkage cracks, with aperture dynamically depending on matrix water content, and permanent macropores, independent of matrix saturation. In the shrinkage cracks sub-domain, a kinematic wave equation was derived by considering laminar motion of thin water films, along two parallel nearly vertical walls; in the permanent macropores sub-domain, a kinematic wave equation was assumed, with parameters physically related with macropores shape and dimension. Exchange of water between macropore domains and matrix was introduced in form of sink terms in the macropores mass balance equations, and as source terms in the matrix continuity equation. Infiltration through macropore walls was modelled using a diffusivity function derived from aggregates sorptivity measurements. The internal catchment was included by considering at each layer a fraction of dead end permanent macropores. Water ponding at the bottom of dead end macropores, infiltrated into the corresponding matrix layer. The model was tested against the results of infiltration transients through a large undisturbed swelling and shrinking clay soil column. Outflow rate from column bottom surface was constantly measured, while water content profile was registered at regular time intervals by means of five TDR horizontal probes. In order to quantify model parameters, characterisation of soil matrix was carried out, providing hydraulic conductivity curve, water retention curve, shrinkage characteristic and aggregates diffusivity. All of the other model parameters, thanks to their clear physical meaning, were estimated from direct observation of soil structure, except macropores morphologic parameters, some of which, although measurable, were obtained by calibration due to

  13. Fabrication of hydrophobic polymer foams with double acid sites on surface of macropore for conversion of carbohydrate.

    Science.gov (United States)

    Pan, Jianming; Mao, Yanli; Gao, Heping; Xiong, Qingang; Qiu, Fengxian; Zhang, Tao; Niu, Xiangheng

    2016-06-05

    Herein we reported a simple and novel synthetic strategy for the fabrication of two kinds of hydrophobic polymer foam catalysts (i.e. Cr(3+)-HPFs-1-H(+) and HPFs-1-H(+)) with hierarchical porous structure, inhomogeneous acidic composition and Lewis-Brønsted double acid sites distributed on the surface, which was used to one-pot conversion of carbohydrate (such as cellulose, glucose and fructose) to a key chemical platform (i.e. 5-hydroxymethylfurfural, HMF). The water-in-oil (W/O) high internal phase emulsions (HIPEs), stabilized by both Span 80 and acidic prepolymers as analogous particles offered the acidic actives, were used as the template for simultaneous polymerization of oil phase in the presence of divinylbenzene (DVB) and styrene (St). After subsequent ion-exchange process, Lewis and Brønsted acid sites derived from exchanged Cr(3+) and H(+) ion were both fixed on the surface of cell of the catalysts. The HPFs-1-H(+) and Cr(3+)-HPFs-1-H(+) had similar hierarchical porous, hydrophobic surface and acid sites (HPFs-1-H(+) with macropores ranging from 0.1 μm to 20 μm, uniform mesopores in 14.4 nm, water contact angle of 122° and 0.614 mmolg(-1) of Brønsted acid sites, as well as Cr(3+)-HPFs-1-H(+) with macropores ranging from 0.1 μm to 20 μm, uniform mesopores in 13.3 nm, water contact angle of 136° and 0.638 mmolg(-1) of Lewis-Brønsted acid sites). It was confirmed that Lewis acid sites of catalyst had a slight influence on the HMF yield of fructose came from the function of Brønsted acid sites, and Lewis acid sites were in favor of improving the HMF yield from cellulose and glucose. This work opens up a simple and novel route to synthesize multifunctional polymeric catalysts for efficient one-pot conversion of carbohydrate to HMF.

  14. New 3-D microarray platform based on macroporous polymer monoliths.

    Science.gov (United States)

    Rober, M; Walter, J; Vlakh, E; Stahl, F; Kasper, C; Tennikova, T

    2009-06-30

    Polymer macroporous monoliths are widely used as efficient sorbents in different, mostly dynamic, interphase processes. In this paper, monolithic materials strongly bound to the inert glass surface are suggested as operative matrices at the development of three-dimensional (3-D) microarrays. For this purpose, several rigid macroporous copolymers differed by reactivity and hydrophobic-hydrophilic properties were synthesized and tested: (1) glycidyl methacrylate-co-ethylene dimethacrylate (poly(GMA-co-EDMA)), (2) glycidyl methacrylate-co-glycerol dimethacrylate (poly(GMA-co-GDMA)), (3) N-hydroxyphthalimide ester of acrylic acid-co-glycidyl methacrylate-co-ethylene dimethacrylate (poly(HPIEAA-co-GMA-co-EDMA)), (4) 2-cyanoethyl methacrylate-co-ethylene dimethacrylate (poly(CEMA-co-EDMA)), and (5) 2-cyanoethyl methacrylate-co-2-hydroxyethyl methacrylate-co-ethylene dimethacrylate (poly(CEMA-co-HEMA-co-EDMA)). The constructed devices were used as platforms for protein microarrays construction and model mouse IgG-goat anti-mouse IgG affinity pair was used to demonstrate the potential of developed test-systems, as well as to optimize microanalytical conditions. The offered microarray platforms were applied to detect the bone tissue marker osteopontin directly in cell culture medium.

  15. Preparative Purification of Liriodendrin from Sargentodoxa cuneata by Macroporous Resin

    Directory of Open Access Journals (Sweden)

    Di-Hua Li

    2015-01-01

    Full Text Available The preparative purification of liriodendrin from Sargentodoxa cuneata using macroporous resin combined with crystallization process was evaluated. The properties of adsorption/desorption of liriodendrin on eight macroporous resins were investigated systematically. X-5 resin was selected as the most suitable medium for liriodendrin purification. The adsorption of liriodendrin on X-5 resin fitted well with the pseudo-second-order kinetic model and Langmuir isotherm model. Dynamic adsorption/desorption tests were performed using a glass column packed with X-5 resin to optimize the separation process of liriodendrin. After one treatment with X-5 resin, the content of liriodendrin in the product was increased 48.73-fold, from 0.85% to 41.42%, with a recovery yield of 88.9%. 97.48% liriodendrin was obtained by further crystallization and determined by HPLC. The purified product possessed strong antioxidant activity. In conclusion, purification of liriodendrin might expend its further pharmacological researches and further applications in pharmacy.

  16. Beaded streams of Arctic permafrost landscapes

    Directory of Open Access Journals (Sweden)

    C. D. Arp

    2014-07-01

    Full Text Available Beaded streams are widespread in permafrost regions and are considered a common thermokarst landform. However, little is known about their distribution, how and under what conditions they form, and how their intriguing morphology translates to ecosystem functions and habitat. Here we report on a Circum-Arctic inventory of beaded streams and a watershed-scale analysis in northern Alaska using remote sensing and field studies. We mapped over 400 channel networks with beaded morphology throughout the continuous permafrost zone of northern Alaska, Canada, and Russia and found the highest abundance associated with medium- to high-ice content permafrost in moderately sloping terrain. In the Fish Creek watershed, beaded streams accounted for half of the drainage density, occurring primarily as low-order channels initiating from lakes and drained lake basins. Beaded streams predictably transition to alluvial channels with increasing drainage area and decreasing channel slope, although this transition is modified by local controls on water and sediment delivery. Comparison of one beaded channel using repeat photography between 1948 and 2013 indicate relatively stable form and 14C dating of basal sediments suggest channel formation may be as early as the Pleistocene–Holocene transition. Contemporary processes, such as deep snow accumulation in stream gulches effectively insulates river ice and allows for perennial liquid water below most beaded stream pools. Because of this, mean annual temperatures in pool beds are greater than 2 °C, leading to the development of perennial thaw bulbs or taliks underlying these thermokarst features. In the summer, some pools stratify thermally, which reduces permafrost thaw and maintains coldwater habitats. Snowmelt generated peak-flows decrease rapidly by two or more orders of magnitude to summer low flows with slow reach-scale velocity distributions ranging from 0.1 to 0.01 m s−1, yet channel runs still move water

  17. Bead-Fourier path integral molecular dynamics

    Science.gov (United States)

    Ivanov, Sergei D.; Lyubartsev, Alexander P.; Laaksonen, Aatto

    2003-06-01

    Molecular dynamics formulation of Bead-Fourier path integral method for simulation of quantum systems at finite temperatures is presented. Within this scheme, both the bead coordinates and Fourier coefficients, defining the path representing the quantum particle, are treated as generalized coordinates with corresponding generalized momenta and masses. Introduction of the Fourier harmonics together with the center-of-mass thermostating scheme is shown to remove the ergodicity problem, known to pose serious difficulties in standard path integral molecular dynamics simulations. The method is tested for quantum harmonic oscillator and hydrogen atom (Coulombic potential). The simulation results are compared with the exact analytical solutions available for both these systems. Convergence of the results with respect to the number of beads and Fourier harmonics is analyzed. It was shown that addition of a few Fourier harmonics already improves the simulation results substantially, even for a relatively small number of beads. The proposed Bead-Fourier path integral molecular dynamics is a reliable and efficient alternative to simulations of quantum systems.

  18. 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.

  19. Formulation and In Vitro evaluation of pH sensitive oil entrapped polymeric blended gellan gum buoyant beads of clarithromycin

    Directory of Open Access Journals (Sweden)

    G Tripathi

    2010-12-01

    Full Text Available "n  "nBackground and the purpose of the study: A gastroretentive pH sensitive system has been a frontier approach to release the drug in controlled manner in stomach and duodenum. The aim of this study was to develop buoyant beads of gellan based, wherein, the oil was entrapped, blended with hydroxypropyl methyl cellulose or carbopol 934 in order to evaluate its potential for targeted sustained delivery of clarithromycin in the gastric region. "nMethods: Buoyant beads of gellan was developed by inotropic gelation technique using calcium carbonate as gas forming agent and the drug polymer dispersion was emulsified with mineral oil. The oil was entrapped and blended with hydroxypropyl methyl cellulose or carbopol 934. The developed beads were evaluated in terms of diameter, % floating, encapsulation efficiency, In vitro drug release, In vivo gastric residence efficacy and clarithromycine concentration in the mucosa of the experimental animal model. "nResults: The scanning electron microscope photograph indicated that the prepared beads were spherical in shape and buoyancy, encapsulation efficiency and drug content obtained from all batches were satisfactory. Particle size and percentage buoyancy of the gel beads increased by raising the concentration of calcium carbonate. The formulation exhibited sustained release profile and was best fitted in the Peppas model with n < 0.45. Subsequent coating of microbeads exhibited zero-order sustained pattern of the drug release up to 8 hrs. Batch B4 showed comparatively better residence and the drug concentration in the gastric mucosa of the treated animals. Conclusion:The result provides evidence that the prepared optimized formulation may be used effectively for pH sensitive gastric targeted antibiotic such as clarithromycin.

  20. Cellulosic fibril–rubber nanocomposites

    CSIR Research Space (South Africa)

    Jacob John, Maya

    2010-06-01

    Full Text Available Cellulose is the most abundant polymer on earth- has emerged as an ideal candidate for providing nanoparticles as reinforcing agents. There is a growing interest in cellulose nanocomposites within the research community and especially...

  1. Acid hydrolysis of cellulose

    Energy Technology Data Exchange (ETDEWEB)

    Salazar, H.

    1980-12-01

    One of the alternatives to increase world production of etha nol is by the hydrolysis of cellulose content of agricultural residues. Studies have been made on the types of hydrolysis: enzimatic and acid. Data obtained from the sulphuric acid hydrolysis of cellulose showed that this process proceed in two steps, with a yield of approximately 95% glucose. Because of increases in cost of alternatives resources, the high demand of the product and the more economic production of ethanol from cellulose materials, it is certain that this technology will be implemented in the future. At the same time further studies on the disposal and reuse of the by-products of this production must be undertaken.

  2. 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

  3. Direct friction measurement in draw bead testing

    DEFF Research Database (Denmark)

    Olsson, David Dam; Bay, Niels; Andreasen, Jan Lasson

    2005-01-01

    have been reported in literature. A major drawback in all these studies is that friction is not directly measured, but requires repeated measurements of the drawing force with and without relative sliding between the draw beads and the sheet material. This implies two tests with a fixed draw bead tool...... and a freely rotating tool respectively, an approach, which inevitably implies large uncertainties due to scatter in the experimental conditions. In order to avoid this problem a new draw bead test is proposed by the authors measuring the friction force acting on the tool radius directly by a build......-in piezoelectric torque transducer. This technique results in a very sensitive measurement of friction, which furthermore enables recording of lubricant film breakdown as function of drawing distance. The proposed test is validated in an experimental investigation of the influence of lubricant viscosity...

  4. Links between matrix bulk density, macropore characteristics and hydraulic behavior of soils

    DEFF Research Database (Denmark)

    Katuwal, Sheela; Møldrup, Per; Lamandé, Mathieu

    2013-01-01

    The relationship of soil bulk density with the hydraulic behavior of soil and the role of macropores in preferential flow and transport has been extensively studied in literatures. Yet, the influence of soil structural heterogeneity as simultaneous variation of bulk density and macropore characte......The relationship of soil bulk density with the hydraulic behavior of soil and the role of macropores in preferential flow and transport has been extensively studied in literatures. Yet, the influence of soil structural heterogeneity as simultaneous variation of bulk density and macropore...... resolution X-ray CT and linked them with laboratory measurements of air permeability and leaching experiment. In addition to macropore characteristics, we also quantified the CT-number of the matrix as a measure of the bulk density of the matrix, i.e., excluding macropores in the soil. Soils from the two...... field sites had similar texture (loam or sandy loam), yet the sand content was higher in Faardrup soils and clay and organic carbon content were higher in Silstrup soils. In general, Silstrup soil had more macropores (>1.2mm) than Faardrup soils but both the soils exhibited similar relationships between...

  5. Synthesis of 3D ordered macroporous indium tin oxide using polymer colloidal crystal template

    Institute of Scientific and Technical Information of China (English)

    ZHANG; Xue'ao; MAN; Yahui; WANG; Jianfang; LIU; Changli; WU; Wenjian

    2006-01-01

    Three-dimensional (3D) ordered macroporous indium tin oxide (ITO) is prepared using a polymer colloidal crystal template that is formed by self-assembly of the monodisperse poly(methyl methacrylate) (PMMA) microspheres. The morphologies and BET surface area of the macroporous material is examined by scanning electron microscope, transmission electron microscopy and N2 adsorption/desorption. Results indicate that the macroporous material has highly ordered arrays of the uniform pores replicated from the PMMA colloidal crystal template when the polymer colloidal crystal template is removed by calcinations at 500℃. The pore diameter (about 450 nm) of macroporous ITO slightly shrank to the PMMA microspheres. The BET surface area and pore volume of the macroporous material are 389 m2·g-1 and 0.36 cm3·g-1, respectively. Moreover, the macroporous ITO, containing 5 mol% Sn and after annealing under vacuum, shows the minimum resistivity of ρ= 8.2×10-3 Ω· cm. The conductive mechanism of macroporous ITO is discussed, and it is believed that the oxygen vacancies are the major factor for excellent electrical properties.

  6. Bead and Process for Removing Dissolved Metal Contaminants

    Energy Technology Data Exchange (ETDEWEB)

    Summers, Bobby L., Jr.; Bennett, Karen L.; Foster, Scott A.

    2005-01-18

    A bead is provided which comprises or consists essentially of activated carbon immobilized by crosslinked poly (carboxylic acid) binder, sodium silicate binder, or polyamine binder. The bead is effective to remove metal and other ionic contaminants from dilute aqueous solutions. A method of making metal-ion sorbing beads is provided, comprising combining activated carbon, and binder solution (preferably in a pin mixer where it is whipped), forming wet beads, and heating and drying the beads. The binder solution is preferably poly(acrylic acid) and glycerol dissolved in water and the wet beads formed from such binder solution are preferably heated and crosslinked in a convection oven.

  7. Rainfall Simulator Experiments to Investigate Macropore Impacts on Hillslope Hydrological Response

    Directory of Open Access Journals (Sweden)

    Yvonne Smit

    2016-11-01

    Full Text Available Understanding hillslope runoff response to intense rainfall is an important topic in hydrology, and is key to correct prediction of extreme stream flow, erosion and landslides. Although it is known that preferential flow processes activated by macropores are an important phenomena in understanding runoff processes inside a hillslope, hydrological models have generally not embraced the concept of an extra parameter that represents ‘macropores’ because of the complexity of the phenomenon. Therefore, it is relevant to investigate the influence of macropores on runoff processes in an experimental small artificial hillslope. Here, we report on a controlled experiment where we could isolate the influence of macropores without the need for assumptions regarding their characteristics. Two identical hillslopes were designed, of which one was filled with artificial macropores. Twelve artificial rainfall events were applied to the two hillslopes and results of drainage and soil moisture were investigated. After the experiments, it could be concluded that the influence of macropores on runoff processes was minimal. The S90 sand used for this research caused runoff to respond fast to rainfall, leading to little or no development of saturation near the macropores. In addition, soil moisture data showed a large amount of pendular water in the hillslopes, which implies that the soil has a low air entry value, and, in combination with the lack of vertical flow, could have caused the pressure difference between the matrix and the macropores to vanish sooner and result in equilibrium being reached in a relatively short time. Nevertheless, a better outline is given to determine a correct sand type for these types of experiments and, by using drainage recession analysis to investigate the influences of macropores on runoff, heterogeneity in rainfall intensity can be overcome. This study is a good point of reference to start future experiments from concerning

  8. 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.

  9. Fabrication of Macro-porous β-zeolite by Using Colloidal Polystyrene Spheres as a Template

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    A β-zeolite/polystyrene composite material was synthesized by co-deposition of mono-disperse polystyrene spheres and nano β-zeolite particles in aqueous suspension on a vertical substrate. Macro-porous β-zeolite was obtained after the polystyrene template was removed by calcination. The micro/macro-pore structure of the prepared β-zeolite was highly ordered. In comparison with other assembly methods, the co-deposition method could obtain a highly ordered macro-porous material with relatively large zeolite filling particles, and therefore the co-deposition of particles with different size is a promising method for the fabrication of macro-porous materials.

  10. Adsorption Characteristics of Macroporous Resin for Oil Removal from Desulphurization Wastewater on Board

    Science.gov (United States)

    Li, Tie; Chen, Chen; Jin, Qi; Zhao, Jiao; Tang, Xiaojia; Zhu, Yimin

    2017-01-01

    According to our previous results on the magnesium-based exhaust gas cleaning system (Mg-EGCS), PAHs and total oil content were the main factors affecting the COD in the wastewater. In this work, three kinds of adsorption materials were investigated and macroporous resin was selected for oil removal. The effects of the dosage of macroporous resin, adsorption time and the flow rate were studied, and thermodynamics equation was used to characterize the adsorption process. The results showed that macroporous resin is a good candidate for oil removal from desulphurization wastewater on board, and the COD after treatment can meet the discharge criteria set by the International Maritime Organization (IMO).

  11. 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.

  12. 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

  13. Calculating cellulose diffraction patterns

    Science.gov (United States)

    Although powder diffraction of cellulose is a common experiment, the patterns are not widely understood. The theory is mathematical, there are numerous different crystal forms, and the conventions are not standardized. Experience with IR spectroscopy is not directly transferable. An awful error, tha...

  14. 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

  15. Quantification and Purification of Mulberry Anthocyanins with Macroporous Resins

    Directory of Open Access Journals (Sweden)

    Xueming Liu

    2004-01-01

    Full Text Available Total anthocyanins in different cultivars of mulberry were measured and a process for the industrial preparation of mulberry anthocyanins as a natural food colorant was studied. In 31 cultivars of mulberry, the total anthocyanins, calculated as cyanidin 3-glucoside, ranged from 147.68 to 2725.46 mg/L juice. Extracting and purifying with macroporous resins was found to be an efficient potential method for the industrial production of mulberry anthocyanins as a food colorant. Of six resins tested, X-5 demonstrated the best adsorbent capability for mulberry anthocyanins (91 mg/mL resin. The adsorption capacity of resins increased with the surface area and the pore radius. Residual mulberry fruit juice after extraction of pigment retained most of its nutrients, except for anthocyanins, and may provide a substrate for further processing.

  16. Separation of capsaicin from capsaicinoids by macroporous resin adsorption chromatography.

    Science.gov (United States)

    Liu, Changxia; Liu, Ruican; Zhang, Peng; Chen, Yiming; Xu, Tao; Wang, Fang; Tan, Tianwei; Liu, Chunqiao

    2015-12-01

    The aim of present study is to develop an efficient and low-cost method for capsaicin production isolated from capsaicinoids by macroporous resin adsorption chromatography. HZ816 resin has shown the best adsorption and desorption capacities for capsaicin among other resins. To optimize the operating parameters for separation, initial concentration, diameter-to-height ratio, mobile phase ratio, and crystallization method were investigated. When capsaicinoids solution (5 g/L) was loaded onto the column (diameter-to-height ratio = 1:12) with ethanol/1% w/w NaOH (4:6, v/v) as the mobile phase, capsaicin was purified most effectively. By using acid neutralization as the crystallization method, the purity of capsaicin improved from 90.3 to 99.5% with 82.3% yield. In conclusion, this study provides a simple and low-cost method for the industrial-scale production of high-purity capsaicin.

  17. Immobilization of bacteria in microgel grafted onto macroporous polyethylene

    Energy Technology Data Exchange (ETDEWEB)

    Trelles, J.A.; Quiroga, F.; Britos, C. [Dpto. de Ciencia y Tecnologia, Universidad Nacional de Quilmes, Roque Saenz Pena 352, (B1876BXD) Bernal, Buenos Aires (Argentina); Smolko, Eduardo E. [Comision Nacional de Energia Atomica, Buenos Aires (Argentina); Grasselli, Mariano, E-mail: mgrasse@unq.edu.a [Dpto. de Ciencia y Tecnologia, Universidad Nacional de Quilmes, Roque Saenz Pena 352, (B1876BXD) Bernal, Buenos Aires (Argentina)

    2010-03-15

    The development of 'Green Chemistry' requires new materials to replace the conventional organic chemistry by biological catalysts, to produce fine chemicals in an environmentally friendly manner. Microbial whole cells can be directly used as biocatalysts, providing a simple and cheap methodology since enzyme isolation and purification are avoided. High-density polyethylene (HDPE) is a very stable polymer though it can be activated by gamma radiation to induce grafting. Glycidyl methacrylate was grafted onto macroporous HDPE and PP in the range of 1-6%, proportional to the initial monomer concentration. Grafted polymers were further chemically modified with ethylenediamine to generate a cationic hydrogel of micron-size thickness onto the internal polymer surfaces. Modified polymers were able to immobilize Gram-positive and Gram-negative bacteria that can catalyze a chemical reaction as efficient as free cells do.

  18. Immobilization of bacteria in microgel grafted onto macroporous polyethylene

    Science.gov (United States)

    Trelles, J. A.; Quiroga, F.; Britos, C.; Smolko, Eduardo E.; Grasselli, Mariano

    2010-03-01

    The development of " Green Chemistry" requires new materials to replace the conventional organic chemistry by biological catalysts, to produce fine chemicals in an environmentally friendly manner. Microbial whole cells can be directly used as biocatalysts, providing a simple and cheap methodology since enzyme isolation and purification are avoided. High-density polyethylene (HDPE) is a very stable polymer though it can be activated by gamma radiation to induce grafting. Glycidyl methacrylate was grafted onto macroporous HDPE and PP in the range of 1-6%, proportional to the initial monomer concentration. Grafted polymers were further chemically modified with ethylenediamine to generate a cationic hydrogel of micron-size thickness onto the internal polymer surfaces. Modified polymers were able to immobilize Gram-positive and Gram-negative bacteria that can catalyze a chemical reaction as efficient as free cells do.

  19. Pillaring effects in macroporous carrageenan-silica composite microspheres.

    Science.gov (United States)

    Boissière, M; Tourrette, A; Devoisselle, J M; Di Renzo, F; Quignard, F

    2006-02-01

    The impregnation of a carrageenan gel by a silica sol is an efficient method to form a composite material which can be conveniently activated by CO2 supercritical drying. The textural properties of the solids have been characterized by nitrogen adsorption-desorption at 77 K and their composition by thermogravimetric analysis and EDX microprobe. Morphology was examined by SEM. The silica-carrageenan composites present an open macroporous structure. Silica particles retained inside the gel behaved as pillars between the polysaccharide fibrils and form a stick-and-ball network. The stiffening of the carrageenan gel by silica prevented its shrinkage upon drying. The nature of the alkali cations affected the retention of silica particles inside the gel. In the absence of silica, carrageenan fibrils rearrange under supercritical drying and form an aerogel with cavities in the mesopore range.

  20. Macroporous hydrogels with tailored morphology and mechanical properties

    Science.gov (United States)

    Bignotti, Fabio; Agnelli, Silvia; Baldi, Francesco; Sartore, Luciana; Peroni, Isabella

    2016-05-01

    In this work it is shown that hydroxyethylcellulose (HEC) can be employed for preparing macroporous polyacrylamide (PAAm) hydrogels with tailored morphology and mechanical properties. By changing the HEC content in the reaction mixture hydrogels with different pore sizes and degrees of interconnectivity can be synthesized. The equilibrium swelling ratio in 0.1 M NaCl increases with the amount of HEC employed. Tensile tests run on equilibrated hydrogels show that these materials behave as rubber-like materials. Their mechanical stiffness decreases regularly as the amount of HEC, and therefore their porosity, is increased. A more complex trend is observed for elongation and stress at break, which display a maximum at intermediate contents of HEC.

  1. ADSORPTION OF MACROPOROUS PHOSPHONIC ACID RESIN FOR INDIUM

    Institute of Scientific and Technical Information of China (English)

    WANG Huijun; XIONG Chunhua; YAO Caiping

    2004-01-01

    The adsorption kinetics and mechanism of a novel chelate resin, macroporous phosphonic acid resin (PAR) for In(III) were investigated. The statically saturated adsorption capacity is 216mg·g-1resin at 298K in HAc-NaAc medium. The apparent adsorption rate constant is k298=4.84×10-5 s-1. The adsorption behavior of PAR for In(III) obeys the Freundlich isotherm. The thermodynamic adsorption parameters, enthalpy change △H, free energy change △G and entropy change △S of PAR for In(III) are 11.5kJ/mol, -12.6kJ/mol and 80.8J/mol·K, respectively. The apparent activation energy is Ea=3.5kJ/mol. The molar coordination ratio of the functional group of PAR to In(III) is about 3∶1.

  2. Fungal cultivation on glass-beads

    DEFF Research Database (Denmark)

    Droce, Aida; Sørensen, Jens Laurids; Giese, Henriette

    Transcription of various bioactive compounds and enzymes are dependent on fungal cultivation method. In this study we cultivate Fusarium graminearum and Fusarium solani on glass-beads with liquid media in petri dishes as an easy and inexpensive cultivation method, that resembles in secondary...

  3. Electro-responsive macroporous polypyrrole scaffolds for triggered dexamethasone delivery.

    Science.gov (United States)

    Seyfoddin, A; Chan, A; Chen, W-T; Rupenthal, I D; Waterhouse, G I N; Svirskis, D

    2015-08-01

    Corticosteroids such as dexamethasone are first line ophthalmic treatment for non-infectious posterior uveitis. Corticosteroids are often administered via intravitreal injection to treat this condition with frequent injections associated with poor treatment adherence and complications such as endophthalmitis. Current ocular implants provide sustained corticosteroid release at predetermined rates and lack the ability for dose individualisation. This study describes the successful fabrication of electrically responsive macroporous polypyrrole (PPy) thin films, and their subsequent application to triggered dexamethasone release. Colloidal crystal films composed of 370nm polymethylmethacrylate colloids were first deposited on ITO coated glass substrates, and subsequently used as sacrificial templates for the fabrication of high surface area, 3-dimensionally ordered macroporous PPy inverse opal (PPy IO) thin films. SEM, UV-Vis reflectance and cyclic voltammetry measurements established that the redox state of the PPy IO films could be controlled via electrical stimulation, which in turn influences both porosity and optical properties of the films. Incorporation of the anti-inflammatory corticosteroid, dexamethasone phosphate (DexP), in the PPy IO films during their fabrication resulted in an effective delivery platform for triggered DexP release. A sustained release profile was observed for the PPy IO-DexP films, bursts of release could be triggered by electrical stimulation. The amount of DexP released from the PPy IO-DexP films was significantly higher than that released from the conventional non-porous PPy-DexP films of comparable mass. Results suggest that electrically responsive PPy IO structures are highly suitable for on-demand drug delivery applications. This technology may enable physicians to fine-tune the required dose according to disease state and patients' needs to enhance the safety and efficacy of corticosteroid treatment. Copyright © 2015 Elsevier B

  4. In vivo behavior of hydrogel beads based on amidated pectins.

    Science.gov (United States)

    Munjeri, O; Collett, J H; Fell, J T; Sharma, H L; Smith, A M

    1998-01-01

    Radio-labeled hydrogel beads, based on amidated pectin, have been produced by adding droplets of an amidated pectin solution to calcium chloride. Incorporation of model drugs into the beads and measurement of the dissolution rate showed that the properties of the beads were unaffected by the incorporation of the radiolabel. The labeled beads were used to carry out an in vivo study of their behavior in the gastrointestinal tract using human volunteers. The volunteers were given the beads after an overnight fast and images were obtained at frequent intervals during transit through the upper gastrointestinal tract and the colon. The beads exhibited rapid gastric emptying and proceeded to pass through the small intestine individually before regrouping at the ileo-caecal junction. Once in the colon, the beads again proceeded as individuals and evidence of the degradation of the beads was observed.

  5. Pesticide transport to tile-drained fields in SWAT model – macropore flow and sediment

    DEFF Research Database (Denmark)

    Lu, Shenglan; Trolle, Dennis; Blicher-Mathiesen, Gitte;

    2015-01-01

    as a fraction of effective rainfall and transported to the tile drains directly. Macropore sediment transport is calculated similarly to the MACRO model (Jarvis et al., 1999). Mobile pesticide transport is calculated with a decay function with the flow, whereas sorbed pesticides transport is associated...... Tool (SWAT) to simulate transport of both mobile (e.g. Bentazon) and strongly sorbed (e.g. Diuron) pesticides in tile drains. Macropore flow is initiated when soil water content exceeds a threshold and rainfall intensity exceeds infiltration capacity. The amount of macropore flow is calculated......Preferential flow and colloidal facilitated transport via macopores connected to tile drains are the main pathways for pesticide transport from agricultural areas to surface waters in some area. We developed a macropore flow module and a sediment transport module for the Soil and Water Assessment...

  6. Flow and transport processes in a macroporous subsurface-drained glacial till soil

    DEFF Research Database (Denmark)

    Villholth, Karen G.; Jensen, Karsten Høgh

    1998-01-01

    -scale concentration gradients, is questioned. Decreasing the domain exchange resulted in an improved model correspondence with the drainage chemograph. The drainage flow pattern was altered between drainage seasons owing to the changes in hydraulic efficiency of surface-vented macropores influenced by the physical......The experimental results from a field-scale tracer experiment in a subsurface-drained glacial till soil were analyzed by the application of a single/dual porosity model (MACRO), optionally accounting for concurrent and interacting flow and transport in the bulk soil porosity as well...... as in the macropores. The model analysis showed that macropore flow is essential in describing the observed transport phenomenon on a short as well as a longer time scale. The diffusive exchange of solute between the matrix and the macropores was very sensitive and critical for the model prediction of the drainage...

  7. Oscillations of light absorption in 2D macroporous silicon structures with surface nanocoatings

    Energy Technology Data Exchange (ETDEWEB)

    Karachevtseva, L., E-mail: lakar@isp.kiev.ua [V. Lashkaryov Institute of Semiconductor Physics, National Academy of Sciences of Ukraine, 41 Nauki Pr., 03028 Kyiv (Ukraine); Kuchmii, S. [L.V. Pisarzhevskii Institute of Physical Chemistry, National Academy of Sciences of Ukraine, 31 Nauki Pr., 03028 Kyiv (Ukraine); Lytvynenko, O.; Sizov, F.; Stronska, O. [V. Lashkaryov Institute of Semiconductor Physics, National Academy of Sciences of Ukraine, 41 Nauki Pr., 03028 Kyiv (Ukraine); Stroyuk, A. [L.V. Pisarzhevskii Institute of Physical Chemistry, National Academy of Sciences of Ukraine, 31 Nauki Pr., 03028 Kyiv (Ukraine)

    2011-02-01

    We investigated the near-IR light absorption oscillations in 2D macroporous silicon structures with microporous silicon layers and CdTe, ZnO surface nanocrystals. The electro-optical effect was taken into account within the strong electric field approximation. Well-separated oscillations were observed in the spectral ranges of the surface bonds of macroporous silicon structures with surface nanocrystals. The model of the resonant electron scattering on impurity states in electric field of heterojunction 'silicon-nanocoating' on macropore surface as well as realization of Wannier-Stark effect on the randomly distributed surface bonds were considered. The Wannier-Stark ladders are not broken by impurities because of the longer scattering lifetime as compared with the period of electron oscillations in an external electric field, in all spectral regions considered for macroporous silicon structures with CdTe and ZnO surface nanocrystals.

  8. Superparamagnetic bead interactions with functionalized surfaces characterized by an immunomicroarray

    DEFF Research Database (Denmark)

    Skottrup, Peter Durand; Hansen, Mikkel Fougt; Moresco, Jacob Lange;

    2010-01-01

    SiO2 performed better than polyethylene glycol-modified surfaces Two beads, Masterbeads and M-280 beads, were found to give superior results compared with other bead types. Antibody/ antigen interactions, Illustrated by C-reactive protein, were best performed with Masterbeads The results provide...

  9. Metal-Containing Polystyrene Beads as Standards for Mass Cytometry.

    Science.gov (United States)

    Abdelrahman, Ahmed I; Ornatsky, Olga; Bandura, Dmitry; Baranov, Vladimir; Kinach, Robert; Dai, Sheng; Thickett, Stuart C; Tanner, Scott; Winnik, Mitchell A

    2010-01-01

    We examine the suitability of metal-containing polystyrene beads for the calibration of a mass cytometer instrument, a single particle analyser based on an inductively coupled plasma ion source and a time of flight mass spectrometer. These metal-containing beads are also verified for their use as internal standards for this instrument. These beads were synthesized by multiple-stage dispersion polymerization with acrylic acid as a comonomer. Acrylic acid acts as a ligand to anchor the metal ions within the interior of the beads. Mass cytometry enabled the bead-by-bead measurement of the metal-content and determination of the metal-content distribution. Beads synthesized by dispersion polymerization that involved three stages were shown to have narrower bead-to-bead variation in their lanthanide content than beads synthesized by 2-stage dispersion polymerization. The beads exhibited insignificant release of their lanthanide content to aqueous solutions of different pHs over a period of six months. When mixed with KG1a or U937 cell lines, metal-containing polymer beads were shown not to affect the mass cytometry response to the metal content of element-tagged antibodies specifically attached to these cells.

  10. A Controlled Drug-Delivery Experiment Using Alginate Beads

    Science.gov (United States)

    Farrell, Stephanie; Vernengo, Jennifer

    2012-01-01

    This paper describes a simple, cost-effective experiment which introduces students to drug delivery and modeling using alginate beads. Students produce calcium alginate beads loaded with drug and measure the rate of release from the beads for systems having different stir rates, geometries, extents of cross-linking, and drug molecular weight.…

  11. A Controlled Drug-Delivery Experiment Using Alginate Beads

    Science.gov (United States)

    Farrell, Stephanie; Vernengo, Jennifer

    2012-01-01

    This paper describes a simple, cost-effective experiment which introduces students to drug delivery and modeling using alginate beads. Students produce calcium alginate beads loaded with drug and measure the rate of release from the beads for systems having different stir rates, geometries, extents of cross-linking, and drug molecular weight.…

  12. MACROPORE FLOW AND MASS WASTING OF GULLIES IN THE LOESS PLATEAU, CHINA

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    Due to the extensive gullying from historically excessive erosion in the loess plateau of China, much of this region is being converted to native grass and shrub vegetation. Tunnel scour and mass wasting are important gully erosion processes resulting from preferential flow through macropores ( pores > 1 mm diameter). The objective of this study is to assess the changes with time in macropore flow characteristics of soils on the Loess Plateau following conversion to grass vegetation and the associated degree of mass wasting of gully faces. Ridge areas that had been revegetated for 1 year, 6 years, and > 15 years following tilling, and for 6 years following contour-ditching and the adjacent gully faces were characterized for their macropore and soil matrix properties on a 50 cm by 50 cm area. The total number of macropores increased from 11.6/m2 to 39.6/m2 from 1 to 6 years and to 51.6/m2 after 15 years of revegetation following tillage. The macroporosity increased from 0.0008 m3/m3 to 0.0018 m3/m3 from 1 to 6 years of revegetation following tillage but the lowest macroporosity (0.0005 m3/m3) was 6 years of revegetation following contour-ditching. The contour-ditched area had the lowest infiltration rate (95 m/d) through the soil matrix (areas without macropores) with the tilled areas having similar infiltration rates regardless of the number of years of revegetation (averaged 146 m/d). Due to tunnel scour erosion of macropores during infiltration into the area revegetated for 1 year, pore diameters enlarged by more than 200% resulting in this condition having the highest individual macropore infiltration rates (7967 m/d). Macropores in all other areas were stable with no tunnel scour erosion of macropores. The total capacity for infiltration through macropores increased significantly with time following revegetation. The number of macropores on the gully faces was triple (92.8/m2) and the macroporosity quadruple (0.004 m3/m3) that of the ridge surfaces. The upper

  13. Preparation and characterization of polystyrene-based monolith with ordered macroporous structure

    Institute of Scientific and Technical Information of China (English)

    Quan Zhou Wu; Jian Feng He; Ji Ming Ou

    2012-01-01

    In this paper,polystyrene-based monoliths with highly ordered macroporous structure were synthesized by using SiO2 colloidal crystal as template.SEM observation shows that the macropores are highly ordered and are interconnected by small windows.The BET surface area of PS monolith is about 36.17 m2/g.The polymer monoliths can resist 5 MPa pressure,showing high mechanical and compressive strength.

  14. Preparative Separation and Purification of the Total Flavonoids in Scorzonera austriaca with Macroporous Resins

    OpenAIRE

    Yang Xie; Qiu-Shi Guo; Guang-Shu Wang

    2016-01-01

    The use of macroporous resins for the separation and purification of total flavonoids to obtain high-purity total flavonoids from Scorzonera austriaca was studied. The optimal conditions for separation and purification of total flavonoids in S. austriaca with macroporous resins were as follows: D4020 resin columns were loaded with crude flavonoid extract solution, and after reaching adsorptive saturation, the columns were eluted successively with 5 bed volumes (BV) of water, 5 BV of 5% (v/v) ...

  15. Ordered macroporous quercetin molecularly imprinted polymers: Preparation, characterization, and separation performance.

    Science.gov (United States)

    Feng, Yonggang; Liu, Qin; Ye, Lifang; Wu, Quanzhou; He, Jianfeng

    2017-02-01

    Ordered macroporous molecularly imprinted polymers were prepared by a combination of the colloidal crystal templating method and the molecular imprinting technique by using SiO2 colloidal crystal as the macroporogen, quercetin as the imprinting template, acrylamide as the functional monomer, ethylene glycol dimethacrylate as the cross-linker and tetrahydrofuran as the solvent. Scanning electron microscopy and Brunauer-Emmett-Teller measurements show that the ordered macroporous molecularly imprinted polymers have a more regular macroporous structure, a narrower pore distribution and a greater porosity compared with the traditional bulk molecularly imprinted polymers. The kinetic and isothermal adsorption behaviors of the polymers were investigated. The results indicate that the ordered macroporous molecularly imprinted polymers have a faster intraparticle mass transfer process and a higher adsorption capacity than the traditional bulk molecularly imprinted polymers. The ordered macroporous molecularly imprinted polymers were further employed as a sorbent for a solid-phase extraction. The results show that the ordered macroporous molecularly imprinted polymers can effectively separate quercetin from the Gingko hydrolysate.

  16. Synthesis of Monodisperse Poly(glycidylmethacrylate-co-ethylene dimethacrylate) Beads and Their Application in Separation of Biopolymers

    Institute of Scientific and Technical Information of China (English)

    GONG, Bo-Lin(龚波林); KE, Cong-Yu(柯从玉); GENG, Xin-Du(耿信笃)

    2004-01-01

    The monodisperse poly(glycidyl methacrylate-co-ethylene dimethacrylate) beads with macroporous in the range of 8.0-12.0 μm were prepared by a single-step swelling and polymerization method. The seed particles prepared by dispersion polymerization exhibited good absorption of the monomer phase. The pore size distribution of the beads was evaluated by gel permeation chromatography and mercury intrusion method. By using this media, a weak cation exchange (WCX) stationary phase for HPLC was synthesized by a new chemical modification method. The prepared resin has advantages of biopolymer separation, high column efficiency, low column backpressure, high protein mass recovery and good resolution for proteins. The measured bioactivity recovery for lysozyme was (96±5)%. The dynamic protein loading capacity of the synthesized WCX packings was 21.3 mg/g. Five proteins were completely separated in 8.0 min using the synthesized WCX stationary phase. The experimental results show that the obtained WCX resin has very weak hydrophobicity. The WCX resin was also used for the rapid separation and purification of lysozyme from egg white in 8 min with only one step . The purity and specific bioactivity of the purified lysozyme was found more than 92.0% and 70184 U/mg, respectively.

  17. Cellulose Isolation Methodology for NMR Analysis of Cellulose Ultrastructure

    Directory of Open Access Journals (Sweden)

    Art J. Ragauskas

    2011-11-01

    Full Text Available In order to obtain accurate information about the ultrastructure of cellulose from native biomass by 13C cross polarization magic angle spinning (CP/MAS NMR spectroscopy the cellulose component must be isolated due to overlapping resonances from both lignin and hemicellulose. Typically, cellulose isolation has been achieved via holocellulose pulping to remove lignin followed by an acid hydrolysis procedure to remove the hemicellulose components. Using 13C CP/MAS NMR and non-linear line-fitting of the cellulose C4 region, it was observed that the standard acid hydrolysis procedure caused an apparent increase in crystallinity of ~10% or less on the cellulose isolated from Populus holocellulose. We have examined the effect of the cellulose isolation method, particularly the acid treatment time for hemicellulose removal, on cellulose ultrastructural characteristics by studying these effects on cotton, microcrystalline cellulose (MCC and holocellulose pulped Populus. 13C CP/MAS NMR of MCC indicated that holocellulose pulping and acid hydrolysis has little effect on the crystalline ultrastructural components of cellulose. Although any chemical method to isolate cellulose from native biomass will invariably alter substrate characteristics, especially those related to regions accessible to solvents, we found those changes to be minimal and consistent in samples of typical crystallinity and lignin/hemicellulose content. Based on the rate of the hemicellulose removal, as determined by HPLC-carbohydrate analysis and magnitude of cellulose ultrastructural alteration, the most suitable cellulose isolation methodology utilizes a treatment of 2.5 M HCl at 100 °C for a standard residence time between 1.5 and 4 h. However, for the most accurate crystallinity results this residence time should be determined empirically for a particular sample.

  18. Enhanced enzymatic hydrolysis of cellulose in microgels.

    Science.gov (United States)

    Chang, Aiping; Wu, Qingshi; Xu, Wenting; Xie, Jianda; Wu, Weitai

    2015-07-04

    A cellulose-based microgel, where an individual microgel contains approximately one cellulose chain on average, is synthesized via free radical polymerization of a difunctional small-molecule N,N'-methylenebisacrylamide in cellulose solution. This microgelation leads to a low-ordered cellulose, favoring enzymatic hydrolysis of cellulose to generate glucose.

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

    Science.gov (United States)

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

    2015-08-01

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

  20. Green stone beads at the dawn of agriculture.

    Science.gov (United States)

    Bar-Yosef Mayer, Daniella E; Porat, Naomi

    2008-06-24

    The use of beads and other personal ornaments is a trait of modern human behavior. During the Middle and Upper Paleolithic periods, beads were made out of shell, bone, ivory, egg shell, and occasionally of minerals. During the transition to agriculture in the Near East, stone, in particular green stone, was used for the first time to make beads and pendants. We observed that a large variety of minerals of green colors were sought, including apatite, several copper-bearing minerals, amazonite and serpentinite. There seems to be an increase with time of distance from which the green minerals were sought. Because beads in white, red, yellow, brown, and black colors had been used previously, we suggest that the occurrence of green beads is directly related to the onset of agriculture. Green beads and bead blanks were used as amulets to ward off the evil eye and as fertility charms.

  1. RF Bead Pull Measurements of the DQW

    CERN Document Server

    Jaume, Guillaume

    2015-01-01

    This report was written within the framework of the CERN Summer Student Program. It is focused on the Radio Frequency study of the Double Quarter Wave Crab Cavity [1] considered for the crab-crossing scheme of the LHC Luminosity upgrade [2]. HFSS simulation [3] and Bead-Pull Measurements technique were used for the characterization of the higher-order terms of the main deflecting mode.

  2. Soil organic carbon, macropore networks and preferential transport

    Science.gov (United States)

    Larsbo, Mats; Koestel, John; Kätterer, Thomas; Jarvis, Nick

    2016-04-01

    Agricultural management practices such as tillage, crop rotations, residue management and fertilization can have a strong influence on soil organic carbon (SOC) stocks. An increase in SOC content will generally improve soil structure, which in turn determines the solute transport pathways through the soil. The aim of this study was to quantify the architecture of macropore networks in undisturbed soil columns (15 cm high, 12.7 cm diameter) sampled along a transect with natural variations in SOC using X-ray tomography and to relate the network characteristics to the degree of preferential transport in the columns. Two tracer experiments were carried out at constant irrigation rates of 2 and 5 mm h-1. We used the normalised 5% arrival time which reflects the tendency for early arrival of the solutes as a measure of the degree of preferential transport. The soil macropore networks were analysed in cylindrical sub-volumes (8 cm high, 10 cm diameter) located centrally within the soil columns. These sub-volumes were considered unaffected by sampling artefacts. Analyses were also carried out the for whole sample volumes to enable comparisons with the results from the transport experiments. Image processing and analysis were carried out in ImageJ and R. The same grey value threshold was applied to all images after harmonisation of grey values using the PVC column walls and the air outside the columns. This approach resulted in a satisfactory separation between the pore space and the surrounding soil matrix and organic matter. The SOC content along the transect, which varied from 4.2 to 15% , was correlated to all measures of the pore network for the sub-volumes except for the connectivity probability. Columns with high SOC content were associated with large macroporosities (both total and connected), large specific surface areas, large fractal dimensions and small mean pore thicknesses. The SOC content for whole sample volumes was positively correlated to 5% arrival times

  3. 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.

  4. Macropore system characteristics controls on non-reactive solute transport at different flow rates

    Science.gov (United States)

    Larsbo, Mats; Koestel, John

    2014-05-01

    Preferential flow and transport in macroporous soils are important pathways for the leaching of agrochemicals through soils. Preferential solute transport in soil is to a large extent determined by the macropore system characteristics and the water flow conditions. The importance of different characteristics of the macropore system is likely to vary with the flow conditions. The objective of this study was to determine which properties of the macropore system that control the shape of non-reactive tracer solute breakthrough curves at different steady-state flow rates. We sampled five undisturbed columns (20 cm high, 20 cm diameter) from the soil surface of four soils with clay contents between 21 and 50 %. Solute transport experiments were carried out under unsaturated conditions at 2, 4, 6, 8 and 12 mm h-1 flow rates. For each flow rate a pulse of potassium bromide solution was applied at the soil surface and the electrical conductivity was measured with high temporal resolution in the column effluent. We used the 5 % arrival time and the holdback factor to estimate the degree of preferential transport from the resulting breakthrough curves. Unsaturated hydraulic conductivities were measured at the soil surface of the columns using a tension disc infiltrometer. The macropore system was imaged by industrial X-ray computed tomography at a resolution of 125 μm in all directions. Measures of the macropore system characteristics including measures of pore continuity were calculated from these images using the ImageJ software. Results show that the degree of preferential transport is generally increasing with flow rate when larger pores become active in the transport. The degree of preferential flow was correlated to measures of macropore topology. This study show that conclusions drawn from experiments carried out at one flow rate should generally not be extrapolated to other flow rates.

  5. Facile fabrication of egg white macroporous sponges for tissue regeneration.

    Science.gov (United States)

    Jalili-Firoozinezhad, Sasan; Rajabi-Zeleti, Sareh; Mohammadi, Parvaneh; Gaudiello, Emanuele; Bonakdar, Shahin; Solati-Hashjin, Mehran; Marsano, Anna; Aghdami, Nasser; Scherberich, Arnaud; Baharvand, Hossein; Martin, Ivan

    2015-10-28

    The availability of 3D sponges combining proper biochemical, biophysical, and biomechanical properties with enhanced capacity of in vivo engraftment and vascularization is crucial in regenerative medicine. A simple process is developed to generate macroporous scaffolds with a well-defined architecture of interconnected pores from chicken egg white (EW), a material with protein- and growth factor-binding features which has not yet been employed in regenerative medicine. The physicomechanical properties and degradation rates of the scaffold are finely tuned by using varying concentrations of the cross-linker, 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride, without alteration of the biochemical traits. In vitro, EW scaffolds supported active metabolism, proliferation, and migration of human dermal fibroblasts, thereby generating uniform cellular constructs. In vivo, subcutaneous implantation in mice reveals negligible immune reaction and efficient cell and tissue ingrowth. Angiogenesis into EW scaffolds is enhanced as compared to standard collagen type I sponges used as reference material, likely due to significantly higher adsorption of the proangiogenic factor vascular endothelial growth factor. In summary, a material is presented derived by facile processing of a highly abundant natural product. Due to the efficient subcutaneous engraftment capacity, the sponges can find utilization for soft tissue regeneration.

  6. Preparation and bioactivity of sol-gel macroporous bioactive glass

    Institute of Scientific and Technical Information of China (English)

    Zhihua Zhou; Jianming Ruan; Jianpeng Zou; Zhongcheng Zhou

    2008-01-01

    Bioactive glass is well known for its ability of bone regeneration, and sol-gel bioactive glass has many advantages com-pared with melt-derived bioactive glass. 3-D scaffold prepared by the sol-gel method is a promising substrate material for bone tissue engineering and large-scale bone repair. Porous sol-gel glass in the CaO-SiO2-P2O5 system with macropores larger than 100 μm was prepared by the addition of stearic acid as a pore former. The diameter of the pore created by the pore former varied from 100 to 300μm. The formation of a hydroxyapatite layer on the glass was analyzed by studying the surface of the porous glass by scanning elec-tron microscopy, energy dispersive spectroscopy, X-ray diffraction, and Raman spectra after they had been immersed in simulated body fluid (SBF) for some time, and the porous glass shows good bioactivity.

  7. Macroporous monoliths for trace metal extraction from seawater

    Energy Technology Data Exchange (ETDEWEB)

    Yue, Yanfeng; Mayes, Richard; Gill, Gary A.; Kuo, Li-Jung; Wood, Jordana R.; Binder, Andrew; Brown, Suree; Dai, Sheng

    2015-05-29

    The viability of seawater-based uranium recovery depends on the uranium adsorption rate and capacity, since the concentration of uranium in the oceans is relatively low (3.3 μgL⁻¹). An important consideration for a fast adsorption is to maximize the adsorption properties of adsorbents such as surface areas and pore structures, which can greatly improve the kinetics of uranium extraction and the adsorption capacity simultaneously. Following this consideration, macroporous monolith adsorbents were prepared from the copolymerization of acrylonitrile (AN) and N,N’-methylenebis(acrylamide) (MBAAm) based on a cryogel method using both hydrophobic and hydrophilic monomers. The monolithic sorbents were tested with simulated seawater containing a high uranyl concentration (–6 ppm) and the uranium adsorption results showed that the adsorption capacities are strongly influenced by the ratio of monomer to the crosslinker, i.e., the density of the amidoxime groups. The preliminary seawater testing indicates the high salinity content of seawater does not hinder the adsorption of uranium.

  8. High energy density supercapacitors using macroporous kitchen sponges

    KAUST Repository

    Chen, Wei

    2012-01-01

    Macroporous, low-cost and recyclable kitchen sponges are explored as effective electrode platforms for supercapacitor devices. A simple and scalable process has been developed to fabricate MnO 2-carbon nanotube (CNT)-sponge supercapacitor electrodes using ordinary kitchen sponges. Two organic electrolytes (1 M of tetraethylammonium tetrafluoroborate (Et 4NBF 4) in propylene carbonate (PC), 1 M of LiClO 4 in PC) are utilized with the sponge-based electrodes to improve the energy density of the symmetrical supercapacitors. Compared to aqueous electrolyte (1 M of Na 2SO 4 in H 2O), the energy density of supercapacitors tripled in Et 4NBF 4 electrolyte, and further increased by six times in LiClO 4 electrolyte. The long-term cycling performance in different electrolytes was examined and the morphology changes of the electrode materials were also studied. The good electrochemical performance in both aqueous and organic electrolytes indicates that the MnO 2-CNT-sponge is a promising low-cost electrode for energy storage systems. © 2012 The Royal Society of Chemistry.

  9. Adsorption of Macroporous Phosphonic Acid Resin for Nickel

    Institute of Scientific and Technical Information of China (English)

    XIONG Chunhua; YAO Caiping; LI Jianrong

    2005-01-01

    The adsorption behavior and mechanism of a novel chelate resin, macroporous phosphonic acid resin ( PAR ) for Ni ( Ⅱ ) were investigated. The statically saturated adsorption capacity is 64.3 mg · g - 1 resin at 298 K in HAc-NaAc medium. The Ni( Ⅱ ) adsorbed on PAR can be elated by 0.5mol· L-1 HCl and the elution percentage reaches 96.6% . The resin can be regenerated and reused without obvious decrease in adsorption capacity. The apparent adsorption rate coastant is k298 = 2.6 × 10-5 s -1 . The adsorption behavior of PAR for Ni ( Ⅱ ) obeys the Freundlich isotherm. The thermodynamic adsorption parameters, enthalpy change △ H, free en ergy change △ G and entropy change △ S of PAR for Ni ( Ⅱ ) are 3. 36 kJ· mol-1 , - 5.47 kJ· mol - 1 and 29.6J·mol-1 · K- 1, respectively. The apparent activation energy is Ea =12 . 2 kJ · mol-1 The molar coordination ratio of the functional group of PAR to Ni( Ⅱ ) is about 4: 1. The adsorption mechanism of PAR for Ni( Ⅱ ) was examined by a chemical method and IR spectrometry.

  10. Acetoacetylation of Hydroxyethyl Cellulose

    Institute of Scientific and Technical Information of China (English)

    陈晓锋; 高彦芳; 杜奕; 刘德山

    2002-01-01

    The acetoacetyl group can be used to improve superabsorbent resins since it is more active than the hydroxyethyl group. The acetoacetyl group can be introduced into the side group of hydroxyethyl cellulose (HEC) to activate HEC using the ester exchange reaction between HEC and ethyl acetoacetate (EAA) to improve HEC grafting. This paper discusses the main factors affecting the reaction, such as the amount of EAA and catalyzer, the reaction temperature, and the reaction time. The acetoacetyl group was successfully introduced into HEC. Within specified ranges, increasing the amount of EAA, the reaction temperature and the reaction time will increase the acetoacetylation.

  11. Cellulose binding domain fusion proteins

    Science.gov (United States)

    Shoseyov, Oded; Shpiegl, Itai; Goldstein, Marc A.; Doi, Roy H.

    1998-01-01

    A cellulose binding domain (CBD) having a high affinity for crystalline cellulose and chitin is disclosed, along with methods for the molecular cloning and recombinant production thereof. Fusion products comprising the CBD and a second protein are likewise described. A wide range of applications are contemplated for both the CBD and the fusion products, including drug delivery, affinity separations, and diagnostic techniques.

  12. Direct Electrospinning of Ultrafine Fibers with Interconnected Macropores Enabled by in Situ Mixing Microfluidics.

    Science.gov (United States)

    Liu, Wanjun; Zhu, Lei; Huang, Chen; Jin, Xiangyu

    2016-12-21

    Porous ultrafine fibers are of great importance to various applications. Herein, we report a method to directly fabricate macro-porous ultrafine fibers by an in situ mixing microfluidics which allows for the simultaneous electrospinning of solution immediately after mixing. The formation mechanism of macro-pores should be attributed to the incomplete mixing coupled with nonsolvent-induced phase separation, which was elucidated by systematical investigation of various solvent systems and mixing solvents. The diameter of the macro-porous fibers can be tuned from 1.80 ± 0.40 to 6.75 ± 0.48 μm by adjusting the solution concentration and the feeding rate of mixing solvent. The results indicated that macro-porous fibers exhibited higher specific surface area (48.66 ± 8.30 m(2) g(-1)), larger pore size (116.73 nm) and pore volume (0.169 ± 0.007 cm(3) g(-1)) than conventional electrospun porous fibers, enabling the high oil absorption capacities of 95.68, 57.98, and 34.82 g g(-1) for silicon oil, motor oil, and peanut oil, respectively. Our method has greatly expanded the solution scope for electrospinning from stable solution systems to unstable or substable solution systems, thus providing intriguing opportunities for the investigation and fabrication of heterogeneous fibers by in situ mixing of various immiscible solvents/solutions. Our findings can serve as guidelines for the electrospinning of ultrafine fibers with interconnected macro-pores (>50 nm).

  13. Reusable macroporous photonic crystal-based ethanol vapor detectors by doctor blade coating.

    Science.gov (United States)

    Ko, Ya-Ling; Tsai, Hui-Ping; Lin, Kun-Yi; Chen, Ying-Chu; Yang, Hongta

    2017-02-01

    This research reports the development of sensitive and reversible vapor detection by using three-dimensional macroporous photonic crystals. A scalable and roll-to-roll compatible doctor blade coating technology is utilized to fabricate flexible macroporous poly(ethoxylated trimethylolpropane triacrylate) (PETPTA) films with hexagonal close-packed pores which are interconnected. The pores are then coated with a layer of poly(2-hydroxyethyl methacrylate) (PHEMA) to create macroporous PHEMA/PETPTA films. The condensation of vapors in the PHEMA coated macroporous films leads to the increase of both the PHEMA swelling degree and the effective refractive index of the diffractive medium, resulting in the red-shift and amplitude reduction of the optical stop bands. The optical measurements reveal that the diffraction from the as-prepared macroporous photonic crystals sensitively monitors the vapor pressure of ethanol since the PHEMA layer displays a great volume dependence on ethanol due to a decreased Flory-Huggins mixing parameter. The dependence of the diffraction wavelength on vapor pressure and the reproducibility of vapor sensing have also been investigated in this study.

  14. [Purification technology of procymidone residues in ginseng extracts by macroporous resins].

    Science.gov (United States)

    Cui, Li-Li; Zheng, Pei-He; Wang, Ying-Ping

    2014-07-01

    The macroporous resin separation technology has been mainly applied in the enrichment of saponins, flavonoids, alkaloids and other ingredients, and used in the removal of heavy metal impurities and pesticide residues in recent years. This paper focuses on the synthesis of the new-type macroporous adsorption resin LKS-11 according to the molecular structure characteristics of procymidone. Specifically, the selective absorptive property and other advantages of macroporous resin were utilized to analyze the procymidone removal efficiency in ginseng extracts from different sources. The type of macroporous resins, absorptive property and desorption conditions were observed respectively by static and dynamic adsorption methods to determined the optimum process conditions. According to the results, LKS-11 showed a good absorptive property to procymidone in ginseng extracts and provided a theoretical basis for studies on the removal of procymidone residues from ginseng extracts by using macroporous adsorption resin. Because of no secondary pollution on samples, low production and operation costs, high procymidone removal efficiency and high product recovery rate, this method is suitable to be applied in production.

  15. Organic matter composition of soil macropore surfaces under different agricultural management practices

    Science.gov (United States)

    Glæsner, Nadia; Leue, Marin; Magid, Jacob; Gerke, Horst H.

    2016-04-01

    Understanding the heterogeneous nature of soil, i.e. properties and processes occurring specifically at local scales is essential for best managing our soil resources for agricultural production. Examination of intact soil structures in order to obtain an increased understanding of how soil systems operate from small to large scale represents a large gap within soil science research. Dissolved chemicals, nutrients and particles are transported through the disturbed plow layer of agricultural soil, where after flow through the lower soil layers occur by preferential flow via macropores. Rapid movement of water through macropores limit the contact between the preferentially moving water and the surrounding soil matrix, therefore contact and exchange of solutes in the water is largely restricted to the surface area of the macropores. Organomineral complex coated surfaces control sorption and exchange properties of solutes, as well as availability of essential nutrients to plant roots and to the preferentially flowing water. DRIFT (Diffuse Reflectance infrared Fourier Transform) Mapping has been developed to examine composition of organic matter coated macropores. In this study macropore surfaces structures will be determined for organic matter composition using DRIFT from a long-term field experiment on waste application to agricultural soil (CRUCIAL, close to Copenhagen, Denmark). Parcels with 5 treatments; accelerated household waste, accelerated sewage sludge, accelerated cattle manure, NPK and unfertilized, will be examined in order to study whether agricultural management have an impact on the organic matter composition of intact structures.

  16. 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

  17. 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.

  18. Microarray of DNA probes on carboxylate functional beads surface

    Institute of Scientific and Technical Information of China (English)

    黄承志; 李原芳; 黄新华; 范美坤

    2000-01-01

    The microarray of DNA probes with 5’ -NH2 and 5’ -Tex/3’ -NH2 modified terminus on 10 um carboxylate functional beads surface in the presence of 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide (EDC) is characterized in the preseni paper. it was found that the microarray capacity of DNA probes on the beads surface depends on the pH of the aqueous solution, the concentra-tion of DNA probe and the total surface area of the beads. On optimal conditions, the minimum distance of 20 mer single-stranded DNA probe microarrayed on beads surface is about 14 nm, while that of 20 mer double-stranded DNA probes is about 27 nm. If the probe length increases from 20 mer to 35 mer, its microarray density decreases correspondingly. Mechanism study shows that the binding mode of DNA probes on the beads surface is nearly parallel to the beads surface.

  19. Microarray of DNA probes on carboxylate functional beads surface

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The microarray of DNA probes with 5′-NH2 and 5′-Tex/3′-NH2 modified terminus on 10 m m carboxylate functional beads surface in the presence of 1-ethyl-3-(3-dimethylaminopropyl)- carbodiimide (EDC) is characterized in the present paper. It was found that the microarray capacity of DNA probes on the beads surface depends on the pH of the aqueous solution, the concentration of DNA probe and the total surface area of the beads. On optimal conditions, the minimum distance of 20 mer single-stranded DNA probe microarrayed on beads surface is about 14 nm, while that of 20 mer double-stranded DNA probes is about 27 nm. If the probe length increases from 20 mer to 35 mer, its microarray density decreases correspondingly. Mechanism study shows that the binding mode of DNA probes on the beads surface is nearly parallel to the beads surface.

  20. HPMA and HEMA copolymer bead interactions with eukaryotic cells

    Directory of Open Access Journals (Sweden)

    Cristina D. Vianna-Soares

    2004-09-01

    Full Text Available Two different hydrophilic acrylate beads were prepared via aqueous suspension polymerization. Beads produced of a hydroxypropyl methacrylate (HPMA and ethyleneglycol methacrylate (EDMA copolymer were obtained using a polyvinyl alcohol suspending medium. Copolymers of 2hydroxyethyl methacrylate (HEMA, methyl methacrylate (MMA and ethyleneglycol methacrylate (EDMA beads were obtained using magnesium hydroxide as the suspending agent. Following characterization by scanning electron microscopy (SEM, nitrogen sorption analysis (NSA and mercury intrusion porosimetry (MIP, the beads were cultured with monkey fibroblasts (COS7 to evaluate their ability to support cell growth, attachment and adhesion. Cell growth behavior onto small HPMA/EDMA copolymer beads and large HEMA/MMA/EDMA copolymer beads is evaluated regarding their hidrophilicity/hidrophobicity and surface roughness.

  1. Metallic gold beads in hyaluronic acid

    DEFF Research Database (Denmark)

    Pedersen, Dan Sonne; Tran, Thao Phuong; Smidt, Kamille;

    2013-01-01

    by exploiting macrophage-induced liberation of gold ions (dissolucytosis) from gold surfaces. Injecting gold beads in hyaluronic acid (HA) as a vehicle into the cavities of the brain can delay clinical signs of disease progression in the MS model, experimental autoimmune encephalitis (EAE). This study....... In conclusion, our findings support that bio-liberation of gold from metallic gold surfaces have anti-inflammatory properties similar to classic gold compounds, warranting further studies into the pharmacological potential of this novel gold-treatment and the possible synergistic effects of hyaluronic acid....

  2. Silica deactivation of bead VOC catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Libanati, C.; Pereira, C.J. [Research Division, W. R. Grace and Co., Columbia, MD (United States); Ullenius, D.A. [Grace TEC Systems, De Pere, WI (United States)

    1998-01-15

    Catalytic oxidation is a key technology for controlling the emissions of Volatile Organic Compounds (VOCs) from industrial plants. The present paper examines the deactivation by silica of bead VOC catalysts in a flexographic printing application. Post mortem analyses of field-aged catalysts suggest that organosilicon compounds contained in the printing ink diffuse into the catalyst and deposit as silica particles in the micropores. Laboratory activity evaluation of aged catalysts suggests that silica deposition is non-selective and that silica masks the noble metal active site

  3. Characterization, visualization and quantification of soil macropores and preferential flow using SPECT and X-ray CAT scanning

    Science.gov (United States)

    Perret, Johan Sebastien

    The presence of soil macropores provides an opportunity for water and associated chemicals to move preferentially through the vadose zone. Most studies on the characterization of macropore flow consider the soil system to be a "black-box". Thus, efforts to describe macropores in quantitative terms have not yet resulted in a comprehensive theoretical framework that allows for a complete representation of their geometry and their effect on preferential flow. Macropore networks in four large undisturbed soil columns (850 mm x 77 mm diameter), were quantified and visualized, both in 2-D and 3-D, using X-ray Computer Assisted Tomography (CAT). Macropore quantification included two-dimensional parameters (i.e., number of macropores, macropore size, hydraulic radius, rectangularity and circularity), and three-dimensional and topological parameters (i.e., macropore length, volume, 3-D hydraulic radius, tortuosity, numerical density, coordination number, and connectivity). Pores larger or equal to 1.0 mm in equivalent diameter were readily detected, visualized and quantified. It was found that the average macroporosity of four soil columns varied between 2.1 and 3.8%. From the hydraulic radius distribution, it was inferred that about 20% of macropore throats have a diameter of 1.6 mm. It was found that the majority of macropore networks had a length of 40 mm, a volume of 60 mm 3 and a wall area of 175 mm2. Breakthrough of potassium iodide was monitored with X-ray CAT scanning. This approach allowed for real-time examination of flow mechanisms through the macropore and matrix flow domains at various depths along the soil column. Flow in the matrix domain suggested that part of the matrix contains small pores (mesopores) that were connected to macropore networks. It is suggested that the matrix domain should be subdivided into two regions: mesopores and micropores. In addition, the macropore domain should be defined both in terms of macropore geometry and its ability to

  4. Immobilized OBOC combinatorial bead array to facilitate multiplicative screening

    OpenAIRE

    Xiao, Wenwu; Bononi, Fernanda C.; Townsend, Jared; Li, Yuanpei; Liu, Ruiwu; Lam, Kit S.

    2013-01-01

    One-bead-one-compound (OBOC) combinatorial library screening has been broadly utilized for the last two decades to identify small molecules, peptides or peptidomimetics targeting variable screening probes such as cell surface receptors, bacteria, protein kinases, phosphatases, proteases etc. In previous screening methods, library beads were suspended in solution and screened against one single probe. Only the positive beads were tracked and isolated for additional screens and finally selected...

  5. Approaching zero cellulose loss in cellulose nanocrystal (CNC) production: recovery and characterization of cellulosic solid residues (CSR) and CNC

    Science.gov (United States)

    Q.Q. Wang; J.Y. Zhu; R.S. Reiner; S.P. Verrill; U. Baxa; S.E. McNeil

    2012-01-01

    This study demonstrated the potential of simultaneously recovering cellulosic solid residues (CSR) and producing cellulose nanocrystals (CNCs) by strong sulfuric acid hydrolysis to minimize cellulose loss to near zero. A set of slightly milder acid hydrolysis conditions than that considered as “optimal” were used to significantly minimize the degradation of cellulose...

  6. Creating nanoshell on the surface of titanium hydride bead

    Directory of Open Access Journals (Sweden)

    PAVLENKO Vyacheslav Ivanovich

    2016-12-01

    Full Text Available The article presents data on the modification of titanium hydride bead by creating titanium nanoshell on its surface by ion-plasma vacuum magnetron sputtering. To apply titanium nanoshell on the titanium hydride bead vacuum coating plant of multifunctional nanocomposite coatings QVADRA 500 located in the center of high technology was used. Analysis of the micrographs of the original surface of titanium hydride bead showed that the microstructure of the surface is flat, smooth, in addition the analysis of the microstructure of material surface showed the presence of small porosity, roughness, mainly cavities, as well as shallow longitudinal cracks. The presence of oxide film in titanium hydride prevents the free release of hydrogen and fills some micro-cracks on the surface. Differential thermal analysis of both samples was conducted to determine the thermal stability of the initial titanium hydride bead and bead with applied titanium nanoshell. Hydrogen thermal desorption spectra of the samples of the initial titanium hydride bead and bead with applied titanium nanoshell show different thermal stability of compared materials in the temperature range from 550 to 860о C. Titanium nanoshells applied in this way allows increasing the heat resistance of titanium hydride bead – the temperature of starting decomposition is 695о C and temperature when decomposition finishes is more than 1000о C. Modified in this way titanium hydride bead can be used as a filler in the radiation protective materials used in the construction or upgrading biological protection of nuclear power plants.

  7. Ormosil Beads for Insulation of Ground Cryogenic Storage Tanks Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Organically modified silica (Ormosil) aerogel beads developed at Aspen Aerogels, Inc. offer several advantages for retrofitting perlite insulation in NASA's ground...

  8. Fast Drug Release Using Rotational Motion of Magnetic Gel Beads

    Directory of Open Access Journals (Sweden)

    Jun-Ichi Takimoto

    2008-03-01

    Full Text Available Accelerated drug release has been achieved by means of the fast rotation of magnetic gel beads. The magnetic gel bead consists of sodium alginate crosslinked by calcium chlorides, which contains barium ferrite of ferrimagnetic particles, and ketoprofen as a drug. The bead underwent rotational motion in response to rotational magnetic fields. In the case of bead without rotation, the amount of drug release into a phosphate buffer solution obeyed non-Fickian diffusion. The spontaneous drug release reached a saturation value of 0.90 mg at 25 minutes, which corresponds to 92% of the perfect release. The drug release was accelerated with increasing the rotation speed. The shortest time achieving the perfect release was approximately 3 minutes, which corresponds to 1/8 of the case without rotation. Simultaneous with the fast release, the bead collapsed probably due to the strong water flow surrounding the bead. The beads with high elasticity were hard to collapse and the fast release was not observed. Hence, the fast release of ketoprofen is triggered by the collapse of beads. Photographs of the collapse of beads, time profiles of the drug release, and a pulsatile release modulated by magnetic fields were presented.

  9. Adsorption of CO2 by alginate immobilized zeolite beads

    Science.gov (United States)

    Suratman, A.; Kunarti, E. S.; Aprilita, N. H.; Pamurtya, I. C.

    2017-03-01

    Immobilized zeolit in alginate beads for adsorption of CO2 was developed. Alginate immobilized zeolit beads was generated by dropping the mixture of Na-alginate and zeolite solution into Ca2+ solution. The adsorption efficacy such as the influence of contact time, mass of zeolite, flowrate of CO2, and mass of adsorbent was evaluated. The adsorption of CO2 onto alginate immobilized zeolit beads was investigated by performing both equilibrium and kinetic batch test. Bead was characterized by FTIR and SEM. Alginate immobilized zeolit beads demonstrated significantly higher sorption efficacy compared to plain alginate beads and zeolite with 0.25 mmol CO2 adsorbed /g adsorbent. Optimum condition was achieved with mass composition of alginate:zeolite (3:1), flowrate 50 mL/min for 20 minutes. The alginate immobilized zeolit beads showed that adsorption of CO2 followed Freundlich isotherm and pseudo second order kinetic model. Adsorption of CO2 onto alginate immobilized zeolite beads is a physisorption with adsorption energy of 6.37 kJ/mol. This results indicates that the alginate immobilized zeolit beads can be used as promising adsorbents for CO2.

  10. Phosphate uptake studies of cross-linked chitosan bead materials.

    Science.gov (United States)

    Mahaninia, Mohammad H; Wilson, Lee D

    2017-01-01

    A systematic experimental study is reported that provides a molecular based understanding of cross-linked chitosan beads and their adsorption properties in aqueous solution containing phosphate dianion (HPO4(2-)) species. Synthetically modified chitosan using epichlorohydrin and glutaraldehyde cross-linkers result in surface modified beads with variable hydrophile-lipophile character and tunable HPO4(2-) uptake properties. The kinetic and thermodynamic adsorption properties of cross-linked chitosan beads with HPO4(2-) species were studied in aqueous solution. Complementary structure and physicochemical characterization of chitosan beads via potentiometry, Raman spectroscopy, DSC, and dye adsorption measurements was carried out to establish structure-property relationships. The maximum uptake (Qm) of bead systems with HPO4(2-) at equilibrium was 52.1mgg(-1); whereas, kinetic uptake results for chitosan bead/phosphate systems are relatively rapid (0.111-0.113min(-1)) with an intraparticle diffusion rate-limiting step. The adsorption process follows a multi-step pathway involving inner- and outer-sphere complexes with significant changes in hydration. Phosphate uptake strongly depends on the composition and type of cross-linker used for preparation of chitosan beads. The adsorption isotherms and structural characterization of bead systems illustrate the role of surface charge, hydrophile-lipophile balance, adsorption site accessibility, and hydration properties of the chitosan bead surface. Copyright © 2016 Elsevier Inc. All rights reserved.

  11. Flow and transport processes in a macroporous subsurface-drained glacial till soil

    DEFF Research Database (Denmark)

    Villholth, Karen Grothe; Jensen, Karsten Høgh; Fredericia, Johnny

    1998-01-01

    The qualitative and quantitative effects of macropore flow and transport in an agricultural subsurface-drained glacial till soil in eastern Denmark have been investigated. Three controlled tracer experiments on individual field plots (each approximately 1000 m(2)) were carried out by surface...... was evidenced directly by the rapid (within 10 mm of water input) and abrupt chloride breakthrough in the drainage water at 1.2 m depth in two of the tracer experiments. In the third experiment, the effect of macropore transport was obvious from the rapid and relatively deep penetration of the tracer...... into the soil profile. Dye infiltration experiments in the field as well as in the laboratory supported the recognition of the dominant contribution of macropores to the infiltration and transport process. The soil matrix significantly influenced the tracer distribution by acting as a source or sink...

  12. Separation and Purification of Total Phloroglucinols inDryopteris crassirhizoma with DM-130 Macroporous Adsorption Resin

    Institute of Scientific and Technical Information of China (English)

    Jin Zhe; Huang Jian-ping; Wang He-meng; Ju han-xun; Ren Si-rui; Chang Ying

    2015-01-01

    To improve the purity of the total phloroglucinols fromDryopteris crassirhizoma extracts, the separation and purification conditions of the total phloroglucinols fromDryopteris crassirhizoma were studied with DM-130 macroporous adsorption resin in this study. Adsorption rate, elution rate and purity of the total phloroglucinols were used as indexes to investigate the adsorption and desorption capacity of the total phloroglucinols with DM-130 macroporous adsorption resin. Through the study, the optimum sample concentration of the total phloroglucinols and maximum sample volume were 1.5 mg• mL-1 and 7 BV (210 mL), respectively. The optimum desorption conditions were achieved by using 80% ethanol as desorption solvent at elution flow rate of 1.0 mL• min-1. The result showed DM-130 macroporous adsorption resin performed effective adsorption and desorption. After purification, the purity of the total phloroglucinols increased by 11.5-fold.

  13. DLTS of p-type Czochralski Si wafers containing processing-induced macropores

    Science.gov (United States)

    Simoen, E.; Depauw, V.; Gordon, I.; Poortmans, J.

    2012-01-01

    The deep levels present in p-type Czochralski silicon with processing-induced macropores in the depletion region have been studied by the deep-level transient (DLT) spectroscopy technique. It is shown that a broad band is present for a bias pulse close to the interface with the Al Schottky contact, which exhibits anomalously slow hole capture and is ascribed to the internal interface states of the macropores. For depths beyond the pore region, other deep levels, associated with point defects—possibly metal contamination during the high-temperature annealing step under H2 ambient--have been observed. The impact of the observed defects on the lifetime of thin-film solar cells, fabricated using macropore-based layer transfer is discussed. Finally, it is shown that the presence of pores in the depletion region, which also affects the DLT-spectrum, alters the capacitance-voltage characteristics.

  14. Non-constrictive bead immobilization leading to decreased and uniform shear stress in microfluidic bead-based ELISA

    CERN Document Server

    Mitra, Kinshuk; Chidambaram, Preethi; Maharry, Aaron P; Xu, Ronald X; Tweedle, Michael F

    2014-01-01

    Microfluidic biosensors have been utilized for sensing a wide range of antigens using numerous configurations. Bead based microfluidic sensors have been a popular modality due to the plug and play nature of analyte choice and the favorable geometry of spherical sensor scaffolds. While constriction of beads against fluid flow remains a popular method to immobilize the sensor, it results in poor fluidic regimes and shear conditions around sensor beads that can affect sensor performance. We present an alternative means of sensor bead immobilization using poly-carbonate membrane. This system results in several orders of magnitude lower variance of flow radially around the sensor bead. Shear stress experienced by our non-constrictive immobilized bead was three orders of magnitude lower. We demonstrate ability to quantitatively sense EpCAM protein, a marker for cancer stem cells and operation under both far-red and green wavelengths with no auto-fluorescence.

  15. Production and in vitro evaluation of macroporous, cell-encapsulating alginate fibres for nerve repair.

    Science.gov (United States)

    Lin, Sharon Chien-Yu; Wang, Yiwei; Wertheim, David F; Coombes, Allan G A

    2017-04-01

    The prospects for successful peripheral nerve repair using fibre guides are considered to be enhanced by the use of a scaffold material, which promotes attachment and proliferation of glial cells and axonal regeneration. Macroporous alginate fibres were produced by extraction of gelatin particle porogens from wet spun fibres produced using a suspension of gelatin particles in 1.5% w/v alginate solution. Gelatin loading of the starting suspension of 40.0, 57.0, and 62.5% w/w resulted in gelatin loading of the dried alginate fibres of 16, 21, and 24% w/w respectively. Between 45 and 60% of the gelatin content of hydrated fibres was released in 1h in distilled water at 37°C, leading to rapid formation of a macroporous structure. Confocal laser scanning microscopy (CLSM) and image processing provided qualitative and quantitative analysis of mean equivalent macropore diameter (48-69μm), pore size distribution, estimates of maximum porosity (14.6%) and pore connectivity. CLSM also revealed that gelatin residues lined the macropore cavities and infiltrated into the body of the alginate scaffolds, thus, providing cell adhesion molecules, which are potentially advantageous for promoting growth of glial cells and axonal extension. Macroporous alginate fibres encapsulating nerve cells [primary rat dorsal root ganglia (DRGs)] were produced by wet spinning alginate solution containing dispersed gelatin particles and DRGs. Marked outgrowth was evident over a distance of 150μm at day 11 in cell culture, indicating that pores and channels created within the alginate hydrogel were providing a favourable environment for neurite development. These findings indicate that macroporous alginate fibres encapsulating nerve cells may provide the basis of a useful strategy for nerve repair. Copyright © 2016 Elsevier B.V. All rights reserved.

  16. Design and Evaluation of a Three Dimensionally Ordered Macroporous Structure within a Highly Patterned Cylindrical Sn-Ni Electrode for Advanced Lithium Ion Batteries

    Directory of Open Access Journals (Sweden)

    Yongcheng Jin

    2013-01-01

    Full Text Available A 3-dimensionally ordered macroporous (3DOM structure within a highly patterned cylindrical Sn-Ni alloy electrode was tailored by using various monodispersed polystyrene (PS templates via a colloidal crystal templating process coupled with an electroplating process. The pore size and the wall thickness in the “inverse opal” 3DOM structure were increased with increasing the size of the PS template beads used in this study. The electrochemical performance of prepared electrodes was examined in order to reveal the correlation between the rate capability and the 3DOM structure. Except the electrode with 1.2 μm pores, the discharge capacities gradually decreased with increasing the current density, showing a capacity conservation ratio of 87% for the electrode with 0.5 μm pores and that of 84% for the electrode with 3.0 μm pores when the current density increased from 0.05 mA cm−2 to 2.0 mA cm−2. The reason for this difference is attributed to the fact that the wall thickness of less than 0.5 μm in the electrode with 1.2 μm pores has a short Li+ diffusion distance in solid-state walls. In addition, it is expected that high regularity of 3DOM structure plays a great role on rate capability. Consequently, the 3DOM structure prepared from 1.2 μm PS template beads was favorable for improving the rate capability.

  17. In vitro biological characterization of macroporous 3D Bonelike structures prepared through a 3D machining technique

    Energy Technology Data Exchange (ETDEWEB)

    Laranjeira, M.S.; Dias, A.G. [INEB - Instituto de Engenharia Biomedica, Divisao de Biomateriais, Universidade do Porto, Rua do Campo Alegre, 823, 4150-180 Porto (Portugal); Santos, J.D. [INEB - Instituto de Engenharia Biomedica, Divisao de Biomateriais, Universidade do Porto, Rua do Campo Alegre, 823, 4150-180 Porto (Portugal); Universidade do Porto, Faculdade de Engenharia, Departamento de Engenharia Metalurgica e Materiais, Rua Dr. Roberto Frias, 4200-465 Porto - Portugal (Portugal); Fernandes, M.H., E-mail: mhrf@portugalmail.pt [Universidade do Porto, Faculdade de Medicina Dentaria, Laboratorio de Farmacologia e Biocompatibilidade Celular, Rua Dr. Manuel Pereira da Silva, 4200-392 Porto (Portugal)

    2009-04-30

    3D bioactive macroporous structures were prepared using a 3D machining technique. A virtual 3D structure model was created and a computer numerically controlled (CNC) milling device machined Bonelike samples. The resulting structures showed a reproducible macroporosity and interconnective structure. Macropores size after sintering was approximately 2000 {mu}m. In vitro testing using human bone marrow stroma showed that cells were able to adhere and proliferate on 3D structures surface and migrate into all macropore channels. In addition, these cells were able to differentiate, since mineralized globular structures associated with cell layer were identified. Results obtained showed that 3D structures of Bonelike successfully allow cell migration into all macropores, and allow human bone marrow stromal cells to proliferate and differentiate. This innovative technique may be considered as a step-forward preparation for 3D interconnective macroporous structures that allow bone ingrowth while maintaining mechanical integrity.

  18. Sol-gel synthesis of macroporous barium zirconate monoliths from ionic precursors via a phase separation route

    Science.gov (United States)

    Guo, Xingzhong; Wang, Zichen; Song, Jie; Yang, Hui

    2017-03-01

    Monolithic macroporous barium zirconate derived from ionic precursors has been successfully prepared via a phase separation route in the presence of poly(ethylene oxide) (PEO) and propyleneoxide (PO). Poly(ethylene oxide) (PEO) acts as a phase separation inducer, while propyleneoxide (PO) acts as a gelation accelerant in the sol-gel process. Appropriate choice of poly(ethylene oxide) (PEO) and propyleneoxide (PO) allows the production of continuous macroporous monolithic gel with a porosity of ca. 63% and a macropore size of 1.8 μm. Some BaCl2 recrystallizes in the dried gel, and subsequently tetragonal ZrO2 phase precipitates after heat-treated at 800 °C. The crystalline phase barium zirconate forms after heat treatment at 1100 °C in air, while the macroporous structure is preserved with a slight increase of porosity and a decrease of macropore size.

  19. 21 CFR 172.868 - Ethyl cellulose.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Ethyl cellulose. 172.868 Section 172.868 Food and... Multipurpose Additives § 172.868 Ethyl cellulose. The food additive ethyl cellulose may be safely used in food in accordance with the following prescribed conditions: (a) The food additive is a cellulose...

  20. 21 CFR 573.420 - Ethyl cellulose.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Ethyl cellulose. 573.420 Section 573.420 Food and... Listing § 573.420 Ethyl cellulose. The food additive ethyl cellulose may be safely used in animal feed in accordance with the following prescribed conditions: (a) The food additive is a cellulose ether...

  1. Cellulose Nanomaterials in Water Treatment Technologies

    OpenAIRE

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

    2015-01-01

    Cellulose nanomaterials are naturally occurring with unique structural, mechanical and optical properties. While the paper and packaging, automotive, personal care, construction, and textiles industries have recognized cellulose nanomaterials’ potential, we suggest cellulose nanomaterials have great untapped potential in water treatment technologies. In this review, we gather evidence of cellulose nanomaterials’ beneficial role in environmental remediation and membranes for water filtration, ...

  2. 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...

  3. STUDIES ON THE SORPTION OF MACROPOROUS PHOSPHONIC ACID RESIN FOR LANTHANUM

    Institute of Scientific and Technical Information of China (English)

    XiongChunhua; ChenYiyong; 等

    1998-01-01

    The influences of Medium pH,sorption temperature,sorption time,etc.on the sorption capacity of macroporous phosphonic acid resin for La3+ were determined.The sorption rate constant was k298=7.64×10-5 s-1. The complex ratio of phosphonic groups of the resin to La3+ was 3:1.The basic sorption parameters were determined. The sorption mechanism of macroporous phosphonic acid resin for La3+ was examined by chemical analysis and IR-spectrometry.

  4. Synthesis of N-Doped meso-macroporous carbon and its application to SO2 absorption

    Science.gov (United States)

    Liu, Chao; Zhang, Lei; Hu, Yongqi; Chen, Aibing; Wang, Xiaojing

    2014-12-01

    N-Doped meso-macroporous carbon materials were synthesized using melamine-formaldehyde resin as carbon precursor and silica spheres as a removable template. The as-synthesized carbon materials with a bimodal pores structure (about 3.9 and ˜50-200 nm) display a high surface nitrogen content of 30 wt %. The macropores of carbon materials can be modulated by changing the diameter of template. The SO2 adsorption experiments demonstrate a high adsorption capacity of 78.6 mg g-1 and a considerable stability even over 9 cycles for the carbon materials.

  5. Macroporous Titania Monolith Prepared via Sol-gel Process with Polymer Foam as the Template

    Institute of Scientific and Technical Information of China (English)

    REN, Jian; DU, Zhong-Jie; ZHANG, Chen; LI, Hang-Quan

    2006-01-01

    Macroporous titania monoliths were prepared via sol-gel method using polymer foam as templates. The polymer foam polymerized via concentrated emulsion polymerization was immerged in a solution of titanium(Ⅳ) isopropoxide in 2-propanol, which underwent a sol-gel process. The organic components were subsequently removed by calcination. The effects of various parameters, including the nature of the monomer, the volume fraction of dispersed phase of the concentrated emulsion, and concentration of the sol-gel solution were investigated. The SEM micrographs of the macroporous titania monoliths thus obtained showed that the porous structure of the final material was effectively controllable.

  6. Galactosylated cellulosic sponge for multi-well drug safety testing.

    Science.gov (United States)

    Nugraha, Bramasta; Hong, Xin; Mo, Xuejun; Tan, Looling; Zhang, Wenxia; Chan, Po-Mak; Kang, Chiang Huen; Wang, Yan; Beng, Lu Thong; Sun, Wanxin; Choudhury, Deepak; Robens, Jeffrey M; McMillian, Michael; Silva, Jose; Dallas, Shannon; Tan, Choon-Hong; Yue, Zhilian; Yu, Hanry

    2011-10-01

    Hepatocyte spheroids can maintain mature differentiated functions, but collide to form bulkier structures when in extended culture. When the spheroid diameter exceeds 200 μm, cells in the inner core experience hypoxia and limited access to nutrients and drugs. Here we report the development of a thin galactosylated cellulosic sponge to culture hepatocytes in multi-well plates as 3D spheroids, and constrain them within a macroporous scaffold network to maintain spheroid size and prevent detachment. The hydrogel-based soft sponge conjugated with galactose provided suitable mechanical and chemical cues to support rapid formation of hepatocyte spheroids with a mature hepatocyte phenotype. The spheroids tethered in the sponge showed excellent maintenance of 3D cell morphology, cell-cell interaction, polarity, metabolic and transporter function and/or expression. For example, cytochrome P450 (CYP1A2, CYP2B2 and CYP3A2) activities were significantly elevated in spheroids exposed to β-naphthoflavone, phenobarbital, or pregnenolone-16α-carbonitrile, respectively. The sponge also exhibits minimal drug absorption compared to other commercially available scaffolds. As the cell seeding and culture protocols are similar to various high-throughput 2D cell-based assays, this platform is readily scalable and provides an alternative to current hepatocyte platforms used in drug safety testing applications.

  7. Methane fermentation of cellulose and ligno-cellulosic materials

    Energy Technology Data Exchange (ETDEWEB)

    Bachman, J.S.; Villermaux, S.; Prost, C. (Laboratoire des Sciences du Genie Chimique, 54 - Nancy (France))

    1985-01-01

    Study of the methane fermentation of two simple substrates i.e. pure cellulose and oat straw. Experiments have been carried out in laboratory fermentors with several initial cellulose concentrations and different straw particle sizes. The results show the effect of adding nutrients and enriched seedings with pure cellulolytic or methanogenic bacteria. In each case, the rate limiting step is defined and the degradation kinetics of the two substrates are compared.

  8. Water adsorption properties controlled by coating/filling ordered mesoporous silica inside cellulose membranes.

    Science.gov (United States)

    Kimura, Tatsuo

    2013-09-28

    Porous organic membranes have been utilized as hard templates not only for replication of porous macrostructures but also for fabrication of hierarchical porous solids through infiltration of precursor solutions in ordered mesoporous materials. However, such organic membranes are usually burned out as sacrificial skeletons by calcination. In addition, replicated macropores are too big to enhance properties due to inorganic oxide frameworks. In this study, when cellulose membranes were used as organic membranes, a coating/filling technology of ordered mesoporous silicas was proposed and the water adsorption-desorption properties were directly investigated by using the composite membranes after extraction of nonionic surfactants used. The composite membranes possessed enough adsorption capacity for water, which will be potentially useful for improving total energy efficiency in heat-pump and desiccant air conditioning systems.

  9. Method for preparing spherical ferrite beads and use thereof

    Science.gov (United States)

    Lauf, Robert J.; Anderson, Kimberly K.; Montgomery, Frederick C.; Collins, Jack L.

    2002-01-01

    The invention allows the fabrication of small, dense, highly polished spherical beads of hexagonal ferrites with selected compositions for use in nonreciprocal microwave and mm-wave devices as well as in microwave absorbent or reflective coatings, composites, and the like. A porous, generally spherical bead of hydrous iron oxide is made by a sol-gel process to form a substantially rigid bead having a generally fine crystallite size and correspondingly finely distributed internal porosity. The resulting gel bead is washed and hydrothermally reacted with a soluble alkaline earth salt (typically Ba or Sr) under conditions of elevated temperature and pressure to convert the bead into a mixed hydrous iron-alkaline earth oxide while retaining the generally spherical shape. This mixed oxide bead is then washed, dried, and calcined to produce the desired (BaFe.sub.12 O.sub.19 or SrFe.sub.12 O.sub.19) crystal structure. The calcined bead is then sintered to form a dense bead of the BaFe.sub.12 O.sub.19 and SrFe.sub.12 O.sub.19 phase suitable for polishing and incorporation into various microwave devices and components.

  10. Concepts for increasing gentamicin release from handmade bone cement beads

    NARCIS (Netherlands)

    Rasyid, Hermawan N; van der Mei, Henny C; Frijlink, Henderik W; Soegijoko, Soegijardjo; Van Horn, Jim R; Busscher, Hendrik; Neut, Daniëlle

    2009-01-01

    BACKGROUND AND PURPOSE: Commercial gentamicin-loaded bone cement beads (Septopal) constitute an effective delivery system for local antibiotic therapy. These beads are not available in all parts of the world, and are too expensive for frequent use in others. Thus, orthopedic surgeons worldwide make

  11. Self-encoding resin beads of combinatorial library screening

    Science.gov (United States)

    Lei, Du; Zhao, Yuandi; Cheng, Tongsheng; Zeng, Shaoqun; Luo, Qingming

    2003-07-01

    The latest self-encoding resin bead is a novel technology for solid phase synthesis combinatorial library screening. A new encode-positional deconvolution strategy which was based on that technology been illustrated compared with positional scanning and iterative strategies. The self-encoding resin beads technology provides an efficient method for improving the high-throughput screening of combinatorial library.

  12. Bead magnetorelaxometry with an on-chip magnetoresistive sensor

    DEFF Research Database (Denmark)

    Dalslet, Bjarke Thomas; Damsgaard, Christian Danvad; Donolato, Marco

    2011-01-01

    Magnetorelaxometry measurements on suspensions of magnetic beads are demonstrated using a planar Hall effect sensor chip embedded in a microfluidic system. The alternating magnetic field used for magnetizing the beads is provided by the sensor bias current and the complex magnetic susceptibility...

  13. Bead Capture on Magnetic Sensors in a Microfluidic System

    DEFF Research Database (Denmark)

    Østerberg, Frederik Westergaard; Dalslet, Bjarke Thomas; Damsgaard, Christian Danvad

    2009-01-01

    The accumulation of magnetic beads by gravitational sedimentation and magnetic capture on a planar Hall-effect sensor integrated in a microfluidic channel is studied systematically as a function of the bead concentration, the fluid flow rate, and the sensor bias current. It is demonstrated...

  14. Bead Collage: An Arts-Based Research Method

    Science.gov (United States)

    Kay, Lisa

    2013-01-01

    In this paper, "bead collage," an arts-based research method that invites participants to reflect, communicate and construct their experience through the manipulation of beads and found objects is explained. Emphasizing the significance of one's personal biography and experiences as a researcher, I discuss how my background as an…

  15. Superparamagnetic bead interactions with functionalized surfaces characterized by an immunomicroarray

    DEFF Research Database (Denmark)

    Skottrup, Peter Durand; Hansen, Mikkel Fougt; Moresco, Jacob Lange

    2010-01-01

    Magneto-resistive sensors capable of detecting superparamagnetic micro-/nano-sized beads are promising alternatives to standard diagnostic assays based on absorbance or fluorescence and streptavidin-functionalized beads are widely used as an integral part of these sensors. Here we have developed ...

  16. Nanofibrous polymeric beads from aramid fibers for efficient bilirubin removal.

    Science.gov (United States)

    Peng, Zihang; Yang, Ye; Luo, Jiyue; Nie, Chuanxiong; Ma, Lang; Cheng, Chong; Zhao, Changsheng

    2016-08-16

    Polymer based hemoperfusion has been developed as an effective therapy to remove the extra bilirubin from patients. However, the currently applied materials suffer from either low removal efficiency or poor blood compatibility. In this study, we report the development of a new class of nanofibrous absorbent that exhibited high bilirubin removal efficiency and good blood compatibility. The Kevlar nanofiber was prepared by dissolving micron-sized Kevlar fiber in proper solvent, and the beads were prepared by dropping Kevlar nanofiber solutions into ethanol. Owing to the nanofiborous structure of the Kevlar nanofiber, the beads displayed porous structures and large specific areas, which would facilitate the adsorption of toxins. In the adsorption test, it was noticed that the beads possessed an adsorption capacity higher than 40 mg g(-1) towards bilirubin. In plasma mimetic solutions, the beads still showed high bilirubin removal efficiency. Furthermore, after incorporating with carbon nanotubes, the beads were found to have increased adsorption capacity for human degradation waste. Moreover, the beads showed excellent blood compatibility in terms of a low hemolysis ratio, prolonged clotting times, suppressed coagulant activation, limited platelet activation, and inhibited blood related inflammatory activation. Additionally, the beads showed good compatibility with endothelial cells. In general, the Kevlar nanofiber beads, which integrated with high adsorption capacity, good blood compatibility and low cytotoxicity, may have great potential for hemoperfusion and some other applications in biomedical fields.

  17. Beaded Fiber Mats of PVA Containing Unsaturated Heteropoly Salt

    Institute of Scientific and Technical Information of China (English)

    Guo Cheng YANG; Yan PAN; Jian GONG; Chang Lu SHAO; Shang Bin WEN; Chen SHAO; Lun Yu QU

    2004-01-01

    Poly(vinyl alcohol) (PVA) fiber mats containing unsaturated heteropoly salt was prepared for the first time. IR, X-ray diffraction and SEM photographs characterized the beaded fiber mats.The viscoelasticity and the conductivity of the solution were the key factors that influence the formation of the beaded fiber mats.

  18. Middle stone age shell beads from South Africa

    CSIR Research Space (South Africa)

    Henshilwood, C

    2004-04-16

    Full Text Available undisputed African personal ornaments are 13 ostrich eggshell beads from Enkapune Ya Muto in Kenya similar to 40 ka. Evidence from Eurasia includes two perforated teeth, dated similar to 43 ka, from Bacho Kiro in Bulgaria and 58 marine shell beads from...

  19. WOOD CELLULOSE ACETATE MEMBRANE 179

    African Journals Online (AJOL)

    DR. AMINU

    2013-06-01

    Jun 1, 2013 ... process. The harnessed cellulose was acetylated by the process of step-wise acetylation to a degree of acetylation (DA) of ... several fields including oil recovery (Heinrich and ..... removed by filtration using the membrane was.

  20. Switchable cell trapping using superparamagnetic beads

    Energy Technology Data Exchange (ETDEWEB)

    Bryan, M. T.; Smith, K. H.; Real, M. E.; Bashir, M. A.; Fry, P. W.; Fischer, P.; Im, M.-Y.; Schrefl, T.; Allwood, D. A.; Haycock, J. W.

    2010-04-30

    Ni{sub 81}Fe{sub 19} microwires are investigated as the basis of a switchable template for positioning magnetically-labeled neural Schwann cells. Magnetic transmission X-ray microscopy and micromagnetic modeling show that magnetic domain walls can be created or removed in zigzagged structures by an applied magnetic field. Schwann cells containing superparamagnetic beads are trapped by the field emanating from the domain walls. The design allows Schwann cells to be organized on a surface to form a connected network and then released from the surface if required. As aligned Schwann cells can guide nerve regeneration, this technique is of value for developing glial-neuronal co-culture models in the future treatment of peripheral nerve injuries.

  1. 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)

  2. A NOVEL APPROACH TO SYNTHESIZE CHITOSAN BEADS CROSSLINKED BY EPICHLOROHYDRIN

    Institute of Scientific and Technical Information of China (English)

    WANG Yongjian; BAI Shu; SUN Yan

    2001-01-01

    The present investigation describes a novel method for preparing spherical chitosan particles based on crosslinking with epichlorohydrin. Certain amount of pre-crosslinking agent was added to form chitosan gels by traditional inverse phase suspension polymerization. Then the gels were crosslinked by epichlorohydrin at basic condition to obtain chitosan beads. The effects of reaction conditions, such as crosslinking time, the amount of crosslinking agent and the NaOtt concentration,on the physical properties of the chitosan beads were investigated. The beads were found to have more amino groups in the polymer chains than the beads crosslinked by glutaraldehyde. The capacity for copper ions is as high as 40mg/g. The beads have good mechanical strength and can be reused.

  3. A NOVEL APPROACH TO SYNTHESIZE CHITOSAN BEADS CROSSLINKED BY EPICHLOROHYDRIN

    Institute of Scientific and Technical Information of China (English)

    WANGYongjina; BAIShu; 等

    2001-01-01

    The present investigation describes a novel method for preparing spherical chitosan particles based on crosslinking with epichlorohydrin.Certain amount of pre-crosslinking agent was added to form chitosan gels by traditional inverse phase suspension polymerization.Then the gels were crosslinked by epichlorohydrin at basic condition to obtain chitosan beads.The effects of reaction conditions,such as crosslinking time,the amount of crosslinking agent and the NaOH concentration,on the physical properties of the chitosan beads were investigated.The beads were found to have more amino groups in the polymer chains than the beads crosslinked by glutaraldehyde.The capacity for copper ions in as high as 40mg/g,The beads have good mechanical strength and can be reused.

  4. Self-organizing magnetic beads for biomedical applications

    CERN Document Server

    Gusenbauer, Markus; Reichel, Franz; Exl, Lukas; Bance, Simon; Ozelt, Harald; Schrefl, Thomas

    2011-01-01

    In the field of biomedicine magnetic beads are used for drug delivery and to treat hyperthermia. Here we propose to use self-organized bead structures to isolate circulating tumor cells using lab-on-chip technologies. Typically blood flows past microposts functionalized with antibodies for circulating tumor cells. Creating these microposts with interacting magnetic beads makes it possible to tune the geometry in size, position and shape. We developed a simulation tool that combines micromagnetics and discrete particle dynamics, in order to design micropost arrays made of interacting beads. The simulation takes into account the viscous drag of the blood flow, magnetostatic interactions between the magnetic beads and gradient forces from external aligned magnets. We developed a particle-particle particle-mesh method for effective computation of the magnetic force and torque acting on the particles.

  5. Incorporation of pyrene in polypyrrole/polystyrene magnetic beads.

    Science.gov (United States)

    Głowala, Paulina; Budniak, Adam; Krug, Pamela; Wysocka, Barbara; Berbeć, Sylwia; Dec, Robert; Dołęga, Izabela; Kacprzak, Kamil; Wojciechowski, Jarosław; Kawałko, Jakub; Kępka, Paweł; Kępińska, Daria; Kijewska, Krystyna; Mazur, Maciej

    2014-10-15

    Pyrene, a fluorescent dye, was incorporated into polystyrene particles coated with polypyrrole. The incorporation was achieved by treating the polypyrrole/polystyrene (PPy/PS) beads in a tetrahydrofuran (THF) solution of the pyrene fluorophore followed by rinsing with methanol. The polystyrene cores of the beads swell in THF, allowing penetration of pyrene molecules into the polystyrene structure. The addition of methanol causes contraction of the swollen polystyrene, which encapsulates the dye molecules inside the beads. It is shown that the polypyrrole coating is permeable with respect to both the dye and the solvent, allowing the transport of molecules between the polystyrene cores and the contacting solution. The polypyrrole adlayer can be used as a matrix for the incorporation of magnetic nanoparticles. Embedded particles provide magnetic functionality to the PPy/PS beads. It is demonstrated that the pyrene-loaded beads can be manipulated with an external magnetic field. Copyright © 2014 Elsevier B.V. All rights reserved.

  6. Fluoride removal using lanthanum incorporated chitosan beads.

    Science.gov (United States)

    Bansiwal, Amit; Thakre, Dilip; Labhshetwar, Nitin; Meshram, Siddharth; Rayalu, Sadhana

    2009-11-01

    Highly selective material based on naturally occurring biomaterial namely chitosan has been designed for the defluoridation of water. Lanthanum incorporated chitosan beads (LCB) were prepared using precipitation method. The synthesis was optimized by varying different synthesis parameters namely lanthanum loading, complexation and precipitation time, strength of ammonia solution used for precipitation, drying time, etc. Lanthanum incorporated chitosan beads were characterized using SEM, FTIR, XRD and EDX. Surface area of LCB was observed to be 2.76 m(2)g(-1). The equilibrium adsorption data fitted well to Langmuir adsorption isotherm and showing maximum fluoride adsorption capacity of 4.7 mg g(-1) with negligible lanthanum release. Kinetic study reveals that adsorption of fluoride is fast and follows pseudo-first-order kinetics. The effect of pH was also studied and the best efficiency was observed at pH 5. Presence of sulphate, nitrate and chloride marginally affected the removal efficiency, however drastic reduction in fluoride uptake was observed in the presence of carbonate and bicarbonate. Negative value of change in free energy (DeltaG degrees) and positive value of change in entropy (DeltaS degrees) suggest the adsorption of fluoride by LCB is feasible and spontaneous process. Positive value of change in enthalpy (DeltaH degrees) suggests the process of fluoride adsorption is endothermic in nature. Regeneration study reveals that 1M ammonium chloride solution appears to be the promising regeneration media showing 81.22% regeneration. The adsorption capacity of LCB was similar in fluoride-contaminated ground water collected from Dhar district of Madhya Pradesh, India, as compared to simulated water.

  7. Surface modification of cellulose nanocrystals

    Science.gov (United States)

    Eyley, Samuel; Thielemans, Wim

    2014-06-01

    Chemical modification of cellulose nanocrystals is an increasingly popular topic in the literature. This review analyses the type of cellulose nanocrystal modification reactions that have been published in the literature thus far and looks at the steps that have been taken towards analysing the products of the nanocrystal modifications. The main categories of reactions carried out on cellulose nanocrystals are oxidations, esterifications, amidations, carbamations and etherifications. More recently nucleophilic substitutions have been used to introduce more complex functionality to cellulose nanocrystals. Multi-step modifications are also considered. This review emphasizes quantification of modification at the nanocrystal surface in terms of degree of substitution and the validity of conclusions drawn from different analysis techniques in this area. The mechanisms of the modification reactions are presented and considered with respect to the effect on the outcome of the reactions. While great strides have been made in the quality of analytical data published in the field of cellulose nanocrystal modification, there is still vast scope for improvement, both in data quality and the quality of analysis of data. Given the difficulty of surface analysis, cross-checking of results from different analysis techniques is fundamental for the development of reliable cellulose nanocrystal modification techniques.

  8. TiO₂ beads and TiO₂-chitosan beads for urease immobilization.

    Science.gov (United States)

    Ispirli Doğaç, Yasemin; Deveci, Ilyas; Teke, Mustafa; Mercimek, Bedrettin

    2014-09-01

    The aim of the present study is to synthesize TiO2 beads for urease immobilization. Two different strategies were used to immobilize the urease on TiO2 beads. In the first method (A), urease enzyme was immobilized onto TiO2 beads by adsorption and then crosslinking. In the second method (B), TiO2 beads were coated with chitosan-urease mixture. To determine optimum conditions of immobilization, different parameters were investigated. The parameters of optimization were initial enzyme concentration (0.5; 1; 1.5; 2mg/ml), alginate concentration (1; 2; 3%), glutaraldehyde concentration (1; 2; 3% v/v) and chitosan concentration (2; 3; 4 mg/ml). The optimum enzyme concentrations were determined as 1.5mg/ml for A and 1.0mg/ml for B. The other optimum conditions were found 2.0% (w/v) for alginate concentration (both A and B); 3.0mg/ml for chitosan concentration (B) and 2.0% (v/v) for glutaraldehyde concentration (A). The optimum temperature (20-60°C), optimum pH (3.0-10.0), kinetic parameters, thermal stability (4-70°C), pH stability (4.0-9.0), operational stability (0-230 min) and reusability (20 times) were investigated for characterization. The optimum temperatures were 30°C (A), 40°C (B) and 35°C (soluble). The temperature profiles of the immobilized ureases were spread over a large area. The optimum pH values for the soluble urease and immobilized urease prepared by using methods (A) and (B) were found to be 7.5, 7.0, 7.0, respectively. The thermal stabilities of immobilized enzyme sets were studied and they maintained 50% activity at 65°C. However, at this temperature free urease protected only 15% activity.

  9. Immobilized OBOC combinatorial bead array to facilitate multiplicative screening.

    Science.gov (United States)

    Xiao, Wenwu; Bononi, Fernanda C; Townsend, Jared; Li, Yuanpei; Liu, Ruiwu; Lam, Kit S

    2013-07-01

    One-bead-one-compound (OBOC) combinatorial library screening has been broadly utilized for the last two decades to identify small molecules, peptides or peptidomimetics targeting variable screening probes such as cell surface receptors, bacteria, protein kinases, phosphatases, proteases etc. In previous screening methods, library beads were suspended in solution and screened against one single probe. Only the positive beads were tracked and isolated for additional screens and finally selected for chemical decoding. During this process, the remaining negative beads were not tracked and discarded. Here we report a novel bead immobilization method such that a bead library array can be conveniently prepared and screened in its entirety, sequentially many times with a series of distinct probes. This method not only allows us to increase the screening efficiency but also permits us to determine the binding profile of each and every library bead against a large number of target receptors. As proof of concept, we serially screened a random OBOC disulfide containing cyclic heptapeptide library with three water soluble dyes as model probes: malachite green, bromocresol purple and indigo carmine. This multiplicative screening approach resulted in a rapid determination of the binding profile of each and every bead respective to each of the three dyes. Beads that interacted with malachite green only, bromocresol purple only, or both indigo carmine and bromocresol purple were isolated, and their peptide sequences were determined with microsequencer. Ultimately, the novel OBOC multiplicative screening approach could play a key role in the enhancement of existing on-bead assays such as whole cell binding, bacteria binding, protein binding, posttranslational modifications etc. with increased efficiency, capacity, and specificity.

  10. Metal-induced fluorescence properties of three-dimensionally ordered macroporous silver inverse opal platforms

    Science.gov (United States)

    Chae, Weon-Sik; Lee, Myung-Jin; Kim, Kisun; Hyun, Jerome K.; Jeon, Seokwoo

    2016-02-01

    This study examined the metal-induced fluorescence properties of three-dimensionally ordered macroporous silver inverse opal (IO) films. Electrochemically synthesized silver IO films with a micrometer cavity exhibited notable fluorescence enhancement at the silver frame, and a decrease in fluorescence lifetime. Numerical calculations supported the observations of a higher fluorescence efficiency at the frame than in the cavity.

  11. Polymer-in-a-Silica-Crust Membranes: Macroporous Materials with Tunable Surface Functionality

    NARCIS (Netherlands)

    Urmenyi, Ana M.; Philipse, Albert P.; Lammertink, Rob G.H.; Wessling, Matthias

    2006-01-01

    We report on alkaline hydrolysis of tetraethoxysilane (Stöber synthesis) inside a macroporous polymer matrix resulting in a homogeneous coverage of silica onto the polymer surface. The encapsulation of the polymer struts by a continuous silica crust allows further functionalization with hydrophilic

  12. [Kinetics of serum albumin adsorption on the macroporous glass MPS-250 GKH].

    Science.gov (United States)

    Naumova, L V; El'Kin, G E; Dmitrenko, L V

    1996-01-01

    Intrinsic diffusion (defined as diffusion within micropores or microgranules) was shown to be a major factor that determines the kinetics of bovine serum albumin adsorption to macroporous silica MPS-250 GKh. The effective coefficient of intrinsic diffusion (within the silica phase) was calculated (Def = 7 x 10(-7) cm2/s).

  13. Isolation of brefeldin A from Eupenicillium brefeldianum broth using macroporous resin adsorption chromatography.

    Science.gov (United States)

    Wang, Ya-Jun; Wu, Ye-Fei; Xue, Feng; Wu, Zhi-Xian; Xue, Ya-Ping; Zheng, Yu-Guo; Shen, Yin-Chu

    2012-05-01

    Brefeldin A (BFA) is a macrolide lactone antibiotic, possessing antitumor, antiviral, antifungal activities. In this work, a separation strategy involving one-step macroporous resin adsorption chromatography combined with crystallization was established for BFA purification from Eupenicillium brefeldianum CCTCC M 208113 fermentation broth. Among six macroporous resin adsorbents tested, the non-polar resin HZ830 had the best adsorption and desorption performance. The static equilibrium adsorption data fitted well with the Freundlich equation, and the adsorption kinetic followed the pseudo-second order model. Through experimental optimization of column adsorption and desorption, BFA in purity of 90.4% (w/w), 92.1% (w/w) yield was obtained by a one-step macroporous resin adsorption chromatography, using a stepwise elution protocol. Furthermore, high purity (>99%, w/w) of BFA crystals were prepared from E. brefeldianum CCTCC M 208113 fermentation broth in an overall recovery of 67.0% (w/w), using a combination of adsorption chromatography packed with non-polar macroporous adsorbent HZ830 and crystallization in acetone. Copyright © 2012 Elsevier B.V. All rights reserved.

  14. Activity and Spatial Distribution of Candida antarctica Lipase B Immobilized on Macroporous Organic Polymeric Adsorbents

    DEFF Research Database (Denmark)

    Nielsen, Anne Veller Friis; Andric, Pavle; Munk Nielsen, Per

    2014-01-01

    A systematic study of the influence of carrier particle size (500 − 850 μ m) and enzyme load (26 200 − 66 100 lipase activity units (LU)/g dry carrier) on the content and activity of Candida antarctica lipase B (CALB) immobilized by adsorption onto macroporous poly(methyl methacrylate) (PMM...

  15. Fabrication of Ordered Macroporous CdS and ZnS by Colloidal Crystal Template

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Ordered macroporous semiconductors CdS and ZnS with regular arrays of spherical pores have been fabricated by poly (styrene-acrylic) (PSA) colloidal crystal template. It was found that the exact three-dimensional (3D) structure of the template had been imprinted in the final material.

  16. Interconnected macroporous poly(ethylene glycol) cryogels as a cell scaffold for cartilage tissue engineering.

    Science.gov (United States)

    Hwang, Yongsung; Sangaj, Nivedita; Varghese, Shyni

    2010-10-01

    Macroporous networks of poly(ethylene glycol) (PEG) with interconnected pores can be created by cryogelation techniques. In this study, we describe the potential application of such PEG cryogels as scaffolds for cartilage tissue engineering. Three-dimensional macroporous cryogels were evaluated for chondrocyte growth and production of cartilage-specific extracellular matrix (ECM). Seeded primary bovine chondrocytes showed homogeneous distribution throughout the cryogels. DNA content suggests continuous cell proliferation over 4 weeks of in vitro culture. Analysis of the composition of cell-secreted ECM showed a culture-time-dependent increase in the amount of glycosaminoglycan and collagen. The production of ECM by chondrocytes was confirmed using scanning electron microscopy analysis. Further histological and immunohistological analysis of the cell-laden scaffold confirmed the presence of accumulated cartilage-specific ECM within the scaffold. The interconnected macroporous network promoted diffusion of cell-secreted matrix within the cryogels. Our results indicated that interconnected macroporous PEG cryogels successfully supported attachment, viability, proliferation, and biosynthetic activity of seeded chondrocytes.

  17. Immobilization of denatured DNA to macroporous supports: I. Efficiency of different coupling procedures.

    Science.gov (United States)

    Bünemann, H; Westhoff, P; Herrmann, R G

    1982-11-25

    Methods commonly used for covalent immobilization of single stranded DNA have been applied to several solid supports (Sephadex G-25 and Cellex 410) as well as to a number of macroporous materials (Sepharose C1-6B, C1-2B; Sephacryl S-500 and S-1000). Coupling efficiencies and stability of covalently bound DNA are compared for both classes of materials. The yields of the immobilization reaction for sonicated DNA are only 10-40% for G-25 and Cellex 410 in contrast to 60-80% for C1-6B and S-500. Under optimal conditions, up to 0.5 mg of DNA can be coupled initially per g of wet macroporous material. The immobilized DNAs are lost from the supports in a biphasic manner, with about 10-20% loss per day during the first 2-3 days at 45 degrees C, followed by only about 1% loss per day at the same temperature thereafter. The influence of the coupling procedure on the generation of mismatch effects has been studied in 2.4 M tetraethylammonium chloride solution for the hybrid formation between immobilized and mobile DNA. The degree of mismatch ranged from 0-3% and depended on the method of immobilization. The unspecific absorption of DNA on macroporous materials is sufficiently low to allow efficient hybrid selection. No size limitations have been observed when plastid mRNAs are selected by cloned fragments of plastid DNA immobilized to macroporous Sephacryl S-500.

  18. Rainfall Simulator Experiments to Investigate Macropore Impacts on Hillslope Hydrological Response

    NARCIS (Netherlands)

    Smit, Y.; Teuling, Adriaan J.; van der Ploeg, Martine J.

    2016-01-01

    Understanding hillslope runoff response to intense rainfall is an important topic in hydrology, and is key to correct prediction of extreme stream flow, erosion and landslides. Although it is known that preferential flow processes activated by macropores are an important phenomena in understanding

  19. Macroporous p-GaP Photocathodes Prepared by Anodic Etching and Atomic Layer Deposition Doping.

    Science.gov (United States)

    Lee, Sudarat; Bielinski, Ashley R; Fahrenkrug, Eli; Dasgupta, Neil P; Maldonado, Stephen

    2016-06-29

    P-type macroporous gallium phosphide (GaP) photoelectrodes have been prepared by anodic etching of an undoped, intrinsically n-type GaP(100) wafer and followed by drive-in doping with Zn from conformal ZnO films prepared by atomic layer deposition (ALD). Specifically, 30 nm ALD ZnO films were coated on GaP macroporous films and then annealed at T = 650 °C for various times to diffuse Zn in GaP. Under 100 mW cm(-2) white light illumination, the resulting Zn-doped macroporous GaP consistently exhibit strong cathodic photocurrent when measured in aqueous electrolyte containing methyl viologen. Wavelength-dependent photoresponse measurements of the Zn-doped macroporous GaP revealed enhanced collection efficiency at wavelengths longer than 460 nm, indicating that the ALD doping step rendered the entire material p-type and imparted the ability to sustain a strong internal electric field that preferentially drove photogenerated electrons to the GaP/electrolyte interface. Collectively, this work presents a doping strategy with a potentially high degree of controllability for high-aspect ratio III-V materials, where the ZnO ALD film is a practical dopant source for Zn.

  20. A Hierarchically Micro-Meso-Macroporous Zeolite CaA for Methanol Conversion to Dimethyl Ether

    Directory of Open Access Journals (Sweden)

    Yan Wang

    2016-11-01

    Full Text Available A hierarchical zeolite CaA with microporous, mesoporous and macroporous structure was hydrothermally synthesized by a ”Bond-Blocking” method using organo-functionalized mesoporous silica (MS as a silica source. The characterization by XRD, SEM/TEM and N2 adsorption/desorption techniques showed that the prepared material had well-crystalline zeolite Linde Type A (LTA topological structure, microspherical particle morphologies, and hierarchically intracrystalline micro-meso-macropores structure. With the Bond-Blocking principle, the external surface area and macro-mesoporosity of the hierarchical zeolite CaA can be adjusted by varying the organo-functionalized degree of the mesoporous silica surface. Similarly, the distribution of the micro-meso-macroporous structure in the zeolite CaA can be controlled purposely. Compared with the conventional microporous zeolite CaA, the hierarchical zeolite CaA as a catalyst in the conversion of methanol to dimethyl ether (DME, exhibited complete DME selectivity and stable catalytic activity with high methanol conversion. The catalytic performances of the hierarchical zeolite CaA results clearly from the micro-meso-macroporous structure, improving diffusion properties, favoring the access to the active surface and avoiding secondary reactions (no hydrocarbon products were detected after 3 h of reaction.

  1. Energy efficient bead milling of microalgae: Effect of bead size on disintegration and release of proteins and carbohydrates

    NARCIS (Netherlands)

    Postma, P.R.; Suarez Garcia, E.; Safi, Carl; Yonathan, K.; Olivieri, G.; Barbosa, M.J.; Wijffels, R.H.; Eppink, M.H.M.

    2017-01-01

    The disintegration of three industry relevant algae (Chlorella vulgaris, Neochloris oleoabundans and Tetraselmis suecica) was studied in a lab scale bead mill at different bead sizes (0.3–1 mm). Cell disintegration, proteins and carbohydrates released into the water phase followed a first order

  2. Nanomechanics of cellulose crystals and cellulose-based polymer composites

    Science.gov (United States)

    Pakzad, Anahita

    Cellulose-polymer composites have potential applications in aerospace and transportation areas where lightweight materials with high mechanical properties are needed. In addition, these economical and biodegradable composites have been shown to be useful as polymer electrolytes, packaging structures, optoelectronic devices, and medical implants such as wound dressing and bone scaffolds. In spite of the above mentioned advantages and potential applications, due to the difficulties associated with synthesis and processing techniques, application of cellulose crystals (micro and nano sized) for preparation of new composite systems is limited. Cellulose is hydrophilic and polar as opposed to most of common thermoplastics, which are non-polar. This results in complications in addition of cellulose crystals to polymer matrices, and as a result in achieving sufficient dispersion levels, which directly affects the mechanical properties of the composites. As in other composite materials, the properties of cellulose-polymer composites depend on the volume fraction and the properties of individual phases (the reinforcement and the polymer matrix), the dispersion quality of the reinforcement through the matrix and the interaction between CNCs themselves and CNC and the matrix (interphase). In order to develop economical cellulose-polymer composites with superior qualities, the properties of individual cellulose crystals, as well as the effect of dispersion of reinforcements and the interphase on the properties of the final composites should be understood. In this research, the mechanical properties of CNC polymer composites were characterized at the macro and nano scales. A direct correlation was made between: - Dispersion quality and macro-mechanical properties - Nanomechanical properties at the surface and tensile properties - CNC diameter and interphase thickness. Lastly, individual CNCs from different sources were characterized and for the first time size-scale effect on

  3. A model for simulating the influence of a spatial distribution of large circular macropores on surface runoff

    Science.gov (United States)

    Léonard, J.; Perrier, E.; de Marsily, G.

    2001-12-01

    This paper reports the development and test, at the scale of 1 m2, of an event- based model that aims at simulating the influence of a spatial distribution of large circular macropores on surface runoff. The main originality of this model is that it focuses on the way macropores are supplied with water at the soil surface, by coupling an original model for water interception by individual macropores to a high-resolution spatialized overland flow model. A three-step evaluation of the model was carried out, involving (1) an experimental test of the model for water interception by macropores; (2) a sensitivity analysis of the model to time and space discretization; and (3) a comparison between numerical and field results in the case of runoff on a crusted soil surface with a population of large macropores made by termites in the Sahel. The model was found to accurately simulate the effect of a spatial distribution of large macropores on runoff, and it showed that small heterogeneities, like macropores or areas where a crust has been destroyed, which cover a very limited proportion of the soil surface, can have a high impact on runoff.

  4. DWPF GLASS BEADS AND GLASS FRIT TRANSPORT DEMONSTRATION

    Energy Technology Data Exchange (ETDEWEB)

    Adamson, D; Bradley Pickenheim, B

    2008-11-24

    DWPF is considering replacing irregularly shaped glass frit with spherical glass beads in the Slurry Mix Evaporator (SME) process to decrease the yield stress of the melter feed (a non-Newtonian Bingham Plastic). Pilot-scale testing was conducted on spherical glass beads and glass frit to determine how well the glass beads would transfer when compared to the glass frit. Process Engineering Development designed and constructed the test apparatus to aid in the understanding and impacts that spherical glass beads may have on the existing DWPF Frit Transfer System. Testing was conducted to determine if the lines would plug with the glass beads and the glass frit slurry and what is required to unplug the lines. The flow loop consisted of vertical and horizontal runs of clear PVC piping, similar in geometry to the existing system. Two different batches of glass slurry were tested: a batch of 50 wt% spherical glass beads and a batch of 50 wt% glass frit in process water. No chemicals such as formic acid was used in slurry, only water and glass formers. The glass beads used for this testing were commercially available borosilicate glass of mesh size -100+200. The glass frit was Frit 418 obtained from DWPF and is nominally -45+200 mesh. The spherical glass beads did not have a negative impact on the frit transfer system. The transferring of the spherical glass beads was much easier than the glass frit. It was difficult to create a plug with glass bead slurry in the pilot transfer system. When a small plug occurred from setting overnight with the spherical glass beads, the plug was easy to displace using only the pump. In the case of creating a man made plug in a vertical line, by filling the line with spherical glass beads and allowing the slurry to settle for days, the plug was easy to remove by using flush water. The glass frit proved to be much more difficult to transfer when compared to the spherical glass beads. The glass frit impacted the transfer system to the point

  5. Fast plasma sintering delivers functional graded materials components with macroporous structures and osseointegration properties.

    Science.gov (United States)

    Godoy, R F; Coathup, M J; Blunn, G W; Alves, A L; Robotti, P; Goodship, A E

    2016-04-13

    We explored the osseointegration potential of two macroporous titanium surfaces obtained using fast plasma sintering (FPS): Ti macroporous structures with 400-600 µmØ pores (TiMac400) and 850-1000 µmØ pores (TiMac850). They were compared against two surfaces currently in clinical use: Ti-Growth® and air plasma spray (Ti-Y367). Each surface was tested, once placed over a Ti-alloy and once onto a CoCr bulk substrate. Implants were placed in medial femoral condyles in 24 sheep. Samples were explanted at four and eight weeks after surgery. Push-out loads were measured using a material-testing system. Bone contact and ingrowth were assessed by histomorphometry and SEM and EDX analyses. Histology showed early osseointegration for all the surfaces tested. At 8 weeks, TiMac400, TiMac850 and Ti-Growth® showed deep bone ingrowth and extended colonisation with newly formed bone. The mechanical push-out force was equal in all tested surfaces. Plasma spray surfaces showed greater bone-implant contact and higher level of pores colonisation with new bone than FPS produced surfaces. However, the void pore area in FPS specimens was significantly higher, yet the FPS porous surfaces allowed a deeper osseointegration of bone to implant. FPS manufactured specimens showed similar osseointegration potential to the plasma spray surfaces for orthopaedic implants. FPS is a useful technology for manufacturing macroporous titanium surfaces. Furthermore, its capability to combine two implantable materials, using bulk CoCr with macroporous titanium surfaces, could be of interest as it enables designers to conceive and manufacture innovative components. FPS delivers functional graded materials components with macroporous structures optimised for osseointegration.

  6. ADSORPTION DYNAMICS OF MACROPOROUS POL YMERIC ADSORBENT Ⅱ.The Studies on the FIlm DIffusion Mass—Transfer Process

    Institute of Scientific and Technical Information of China (English)

    WANGChunhong; XUMingcheng; 等

    2000-01-01

    The film diffusion mass-transfer process of adsorption of phenol on macroporous polystyrene resin was investigated in detail.In order to revise the Boyd film diffusion kinetics equation,the out-surface structure of the macroporous resin and that of gel-type ion-exchange resin was compared and the new film diffusion equation was also suggested.These results showed that the film diffusion was influenced by porosity of the macroporous resin greatly,which differed from the film diffustion behavior of ion-exchange resin obviously.

  7. Linking air and water transport in intact soils to macropore characteristics inferred from X-ray computed tomography

    DEFF Research Database (Denmark)

    Katuwal, S.; Nørgaard, Trine; Møldrup, Per

    2015-01-01

    Soil macropores often control fluid flow and solute transport, and quantification of macropore characteristics including their variability in space and time are essential to predict soil hydraulic and hydrogeochemical functions. In this study, measurements of air and solute transport properties...... and direct macropore visualization by X-ray CT scanning were carried out on 17 large (19-cm diam.; 20-cm length) undisturbed soil columns sampled across a field site (Silstrup, Denmark) with natural gradients in texture and density. Air permeability (ka) at in-situ water content and -20 hPa of matric...

  8. Ionic liquid processing of cellulose.

    Science.gov (United States)

    Wang, Hui; Gurau, Gabriela; Rogers, Robin D

    2012-02-21

    Utilization of natural polymers has attracted increasing attention because of the consumption and over-exploitation of non-renewable resources, such as coal and oil. The development of green processing of cellulose, the most abundant biorenewable material on Earth, is urgent from the viewpoints of both sustainability and environmental protection. The discovery of the dissolution of cellulose in ionic liquids (ILs, salts which melt below 100 °C) provides new opportunities for the processing of this biopolymer, however, many fundamental and practical questions need to be answered in order to determine if this will ultimately be a green or sustainable strategy. In this critical review, the open fundamental questions regarding the interactions of cellulose with both the IL cations and anions in the dissolution process are discussed. Investigations have shown that the interactions between the anion and cellulose play an important role in the solvation of cellulose, however, opinions on the role of the cation are conflicting. Some researchers have concluded that the cations are hydrogen bonding to this biopolymer, while others suggest they are not. Our review of the available data has led us to urge the use of more chemical units of solubility, such as 'g cellulose per mole of IL' or 'mol IL per mol hydroxyl in cellulose' to provide more consistency in data reporting and more insight into the dissolution mechanism. This review will also assess the greenness and sustainability of IL processing of biomass, where it would seem that the choices of cation and anion are critical not only to the science of the dissolution, but to the ultimate 'greenness' of any process (142 references).

  9. Calcium Pectinate Beads Formation: Shape and Size Analysis

    Directory of Open Access Journals (Sweden)

    Boon-Beng Lee

    2014-04-01

    Full Text Available The aim of this study was to investigate the inter-relationship between process variables and the size and shape of pectin solution droplets upon detachment from a dripping tip as well as Ca-pectinate beads formed after gelation via image analysis. The sphericity factor (SF of the droplets was generally smaller than 0.05. There was no specific trend between the SF of the droplets and the pectin concentration or the dripping tip radius. The SF the beads formed from high-concentration pectin solutions and a small dripping tip was smaller than 0.05. The results show that the Reynolds number and Ohnesorge number of the droplets fall within the operating region for forming spherical beads in the shape diagram, with the exception to the lower boundary. The lower boundary of the operating region has to be revised to Oh = 2.3. This is because the critical viscosity for Ca-pectinate bead formation is higher than that of Ca-alginate beads. On the other hand, the radius of the droplets and beads increased as the dripping tip radius increased. The bead radius can easily be predicted by Tate’s law equation.

  10. Uptake of mercury by thiol-grafted chitosan gel beads.

    Science.gov (United States)

    Merrifield, John D; Davids, William G; MacRae, Jean D; Amirbahman, Aria

    2004-07-01

    This study describes the synthesis and characterization of thiol-grafted chitosan beads for use as mercury (Hg) adsorbents. Chitosan flakes were dissolved and formed into spherical beads using a phase inversion technique, then crosslinked to improve their porosity and chemical stability. Cysteine was grafted onto the beads in order to improve the adsorption affinity of Hg to the beads. The beads possessed an average diameter of 3.2 mm, porosity of 0.9, specific surface area of approximately 100 m2/g, average pore size of approximately 120 angstroms, and specific gravity of 2.0. Equilibrium and kinetic uptake experiments were conducted to study the uptake of Hg by the beads. The adsorption capacity was approximately 8.0 mmol-Hg/g-dry beads at pH 7, and decreased with decreasing pH. Hg adsorption kinetics was modeled as radial pore diffusion into a spherical bead with nonlinear adsorption. Use of the nonlinear Freundlich isotherm in the diffusion equation allowed modeling of the uptake kinetics with a single tortuosity factor of 1.5 +/- 0.3 as the fitting parameter for all initial Hg concentrations, chitosan loadings, and agitation rates. At agitation rates of 50 and 75 rpm, where uptake rate was reduced significantly due to the boundary layer effect, the mass transfer coefficient at the outside boundary was also used as a fitting parameter to model the kinetic data. At agitation rates higher than 150 rpm, pore diffusion was the rate-limiting step. The beads exhibited a high initial uptake rate followed by a slower uptake rate suggesting pore diffusion as the rate-determining step especially at high agitation rates. Higher uptake rates observed in this study compared to those in a previous study of chitosan-based crab shells indicate that dissolution and gel formation increase the porosity and pore accessibility of chitosan.

  11. Patterning surface by site selective capture of biopolymer hydrogel beads.

    Science.gov (United States)

    Guyomard-Lack, Aurélie; Moreau, Céline; Delorme, Nicolas; Marquis, Mélanie; Fang, Aiping; Bardeau, Jean-François; Cathala, Bernard

    2012-06-01

    This communication describes the fabrication of microstructured biopolymer surfaces by the site-selective capture of pectin hydrogel beads. A positively charged surface consisting of poly-L-lysine (PLL) was subjected to site-selective enzymatic degradation using patterned polydimethylsiloxane (PDMS) stamps covalently modified with trypsin, according to the recently described method. The patterned surface was used to capture ionically cross-linked pectin beads. The desired patterning of the hydrogel surfaces was generated by site-selective immobilization of these pectin beads. The ability of the hydrogels to be dried and swollen in water was assessed.

  12. Simulation of non-linear coaxial line using ferrite beads

    Energy Technology Data Exchange (ETDEWEB)

    Furuya, S.; Matsumoto, H.; Tachi, K.; Takano, S.; Irisawa, J. [Nagaoka Univ. of Technology, Niigata (Japan)

    2002-06-01

    A ferrite sharpener is a non-linear coaxial line using ferrite beads, which produces high-voltage, high-dV/dt pulses. We have been examining the characteristics of ferrite sharpeners experimentally, varying various parameters. Also we have made the simulation of the ferrite sharpener and compared the predictions with the experimental results in detail to analyze the characteristics of the sharpener. In this report, calculating the magnetization M of the ferrite bead, we divide the bead into n sections radially instead of adopting M at the average radius in the previous report. (author)

  13. A High-Throughput SU-8Microfluidic Magnetic Bead Separator

    DEFF Research Database (Denmark)

    Bu, Minqiang; Christensen, T. B.; Smistrup, Kristian

    2007-01-01

    We present a novel microfluidic magnetic bead separator based on SU-8 fabrication technique for high through-put applications. The experimental results show that magnetic beads can be captured at an efficiency of 91 % and 54 % at flow rates of 1 mL/min and 4 mL/min, respectively. Integration...... of soft magnetic elements in the chip leads to a slightly higher capturing efficiency and a more uniform distribution of captured beads over the separation chamber than the system without soft magnetic elements....

  14. Towards a programmable magnetic bead microarray in a microfluidic channel

    DEFF Research Database (Denmark)

    Smistrup, Kristian; Bruus, Henrik; Hansen, Mikkel Fougt

    2007-01-01

    A new hybrid magnetic bead separator that combines an external magnetic field with 175@mm thick current lines buried in the back side of a silicon wafer is presented. A microfluidic channel was etched into the front side of the wafer. The large cross-section of the current lines makes it possible...... to use larger currents and obtain forces of longer range than from thin current lines at a given power limit. Guiding of magnetic beads in the hybrid magnetic separator and the construction of a programmable microarray of magnetic beads in the microfluidic channel by hydrodynamic focusing is presented....

  15. Biopolymer foams - Relationship between material characteristics and foaming behavior of cellulose based foams

    Science.gov (United States)

    Rapp, F.; Schneider, A.; Elsner, P.

    2014-05-01

    Biopolymers are becoming increasingly important to both industry and consumers. With regard to waste management, CO2 balance and the conservation of petrochemical resources, increasing efforts are being made to replace standard plastics with bio-based polymers. Nowadays biopolymers can be built for example of cellulose, lactic acid, starch, lignin or bio mass. The paper will present material properties of selected cellulose based polymers (cellulose propionate [CP], cellulose acetate butyrate [CAB]) and corresponding processing conditions for particle foams as well as characterization of produced parts. Special focus is given to the raw material properties by analyzing thermal behavior (differential scanning calorimetry), melt strength (Rheotens test) and molecular weight distribution (gel-permeation chromatography). These results will be correlated with the foaming behavior in a continuous extrusion process with physical blowing agents and underwater pelletizer. Process set-up regarding particle foam technology, including extrusion foaming and pre-foaming, will be shown. The characteristics of the resulting foam beads will be analyzed regarding part density, cell morphology and geometry. The molded parts will be tested on thermal conductivity as well as compression behavior (E-modulus, compression strength).

  16. Biopolymer foams - Relationship between material characteristics and foaming behavior of cellulose based foams

    Energy Technology Data Exchange (ETDEWEB)

    Rapp, F., E-mail: florian.rapp@ict.fraunhofer.de, E-mail: anja.schneider@ict.fraunhofer.de; Schneider, A., E-mail: florian.rapp@ict.fraunhofer.de, E-mail: anja.schneider@ict.fraunhofer.de [Fraunhofer Institute for Chemical Technology ICT (Germany); Elsner, P., E-mail: peter.elsner@ict.fraunhofer.de [Fraunhofer Institute for Chemical Technology ICT, Germany and Karlsruhe Institute of Technology KIT (Germany)

    2014-05-15

    Biopolymers are becoming increasingly important to both industry and consumers. With regard to waste management, CO{sub 2} balance and the conservation of petrochemical resources, increasing efforts are being made to replace standard plastics with bio-based polymers. Nowadays biopolymers can be built for example of cellulose, lactic acid, starch, lignin or bio mass. The paper will present material properties of selected cellulose based polymers (cellulose propionate [CP], cellulose acetate butyrate [CAB]) and corresponding processing conditions for particle foams as well as characterization of produced parts. Special focus is given to the raw material properties by analyzing thermal behavior (differential scanning calorimetry), melt strength (Rheotens test) and molecular weight distribution (gel-permeation chromatography). These results will be correlated with the foaming behavior in a continuous extrusion process with physical blowing agents and underwater pelletizer. Process set-up regarding particle foam technology, including extrusion foaming and pre-foaming, will be shown. The characteristics of the resulting foam beads will be analyzed regarding part density, cell morphology and geometry. The molded parts will be tested on thermal conductivity as well as compression behavior (E-modulus, compression strength)

  17. Plant cellulose synthesis: CESA proteins crossing kingdoms.

    Science.gov (United States)

    Kumar, Manoj; Turner, Simon

    2015-04-01

    Cellulose is a biopolymer of considerable economic importance. It is synthesised by the cellulose synthase complex (CSC) in species ranging from bacteria to higher plants. Enormous progress in our understanding of bacterial cellulose synthesis has come with the recent publication of both the crystal structure and biochemical characterisation of a purified complex able to synthesis cellulose in vitro. A model structure of a plant CESA protein suggests considerable similarity between the bacterial and plant cellulose synthesis. In this review article we will cover current knowledge of how plant CESA proteins synthesise cellulose. In particular the focus will be on the lessons learned from the recent work on the catalytic mechanism and the implications that new data on cellulose structure has for the assembly of CESA proteins into the large complex that synthesis plant cellulose microfibrils.

  18. 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.

  19. Hierarchically macroporous silver monoliths using Pluronic F127: Facile synthesis, characterization and its application as an efficient biomaterial for pathogens

    Directory of Open Access Journals (Sweden)

    Gowhar Ahmad Naikoo

    2016-03-01

    Full Text Available Herein we report the facile synthesis of three dimensional macroporous (MP silver monoliths serving as intelligent biomaterials against Gram negative (Escherichia coli, Salmonella typhimurium and Gram positive (Bacillus subtilis bacteria with more efficacy against Gram negative bacteria. The macroporous silver monoliths were examined by Fourier transform infra red (FTIR spectroscopy, thermogravimetric analysis (TGA, X-ray diffraction (XRD study, field emission scanning electron microscopy (FESEM, energy dispersion X-ray spectroscopy analysis (EDX and Brunauer–Emmet–Teller (BET adsorption technique. From the antibacterial activity results, it was concluded that macroporous silver monoliths can serve as efficient disinfection agents. The enhanced antibacterial properties of macroporous silver monoliths was possibly due to high surface free energy of the surface Ag+ atoms leading to cell membrane damage followed by cell death.

  20. Development of nonflammable cellulosic foams

    Science.gov (United States)

    Luttinger, M.

    1972-01-01

    The development of a moldable cellulosic foam for use in Skylab instrument storage cushions is considered. Requirements include density of 10 lb cu ft or less, minimal friability with normal handling, and nonflammability in an atmosphere of 70 percent oxygen and 30 percent nitrogen at 6.2 psia. A study of halogenated foam components was made, including more highly chlorinated binders, halogen-containing additives, and halogenation of the cellulose. The immediate objective was to reduce the density of the foam through reduction in inorganic phosphate without sacrificing flame-retarding properties of the foams. The use of frothing techniques was investigated, with particular emphasis on a urea-formaldehyde foam. Halogen-containing flame retardants were deemphasized in favor of inorganic salts and the preparation of phosphate and sulphate esters of cellulose. Utilization of foam products for civilian applications was also considered.

  1. Biocompatibility of Bacterial Cellulose Based Biomaterials

    OpenAIRE

    2012-01-01

    Some bacteria can synthesize cellulose when they are cultivated under adequate conditions. These bacteria produce a mat of cellulose on the top of the culture medium, which is formed by a three-dimensional coherent network of pure cellulose nanofibers. Bacterial cellulose (BC) has been widely used in different fields, such as the paper industry, electronics and tissue engineering due to its remarkable mechanical properties, conformability and porosity. Nanocomposites based on BC have received...

  2. Chitosan beads loaded with essential oils in cosmetic formulations.

    Science.gov (United States)

    Anchisi, C; Meloni, M C; Maccioni, A M

    2006-01-01

    The aim of this work is to evaluate the stability and release of chitosan beads loaded with volatile molecules of Mentha piperita essential oil (E.O.) in a cosmetic formulation. The ability of the beads to quickly release Mentha piperita E.O. during use of a cosmetic formulation such as a bath foam is also assessed. The chitosan beads were produced with three different chitosan dispersions gelled with two different gelling solutions: (a) a 10% solution of sodium hydroxide (NaOH) and (b) a 4% solution of sodium tripolyphosphate (TPP). A few properties of six bead samples loaded with Mentha piperita E.O. are assessed. The properties are morphology, size, swelling ability, encapsulation efficiency, stability in time, and fast release of Mentha piperita E.O. during the use phase of the cosmetic formulation.

  3. Archaeological study of ostrich eggshell beads collected from SDG site

    Institute of Scientific and Technical Information of China (English)

    WANG ChunXue; ZHANG Yue; GAO Xing; ZHANG XiaoLing; WANG HuiMin

    2009-01-01

    Ostrich eggshell beads and fragments collected from SDG site reflect primordial art and a kind of symbolic behavior of modern humans.Based on stratigraphic data and OSL dating,these ostrich eggshell beads are probably in Early Holocene (<10 ka BP).Two different prehistoric manufacturing pathways are usually used in the manufacture of ostrich eggshell beads in Upper Paleolithic.According to statistic analysis of the characteristics of ostrich eggshell beads,Pathway 1 is identified from these collections.In pathway 1,blanks are drilled prior to being trimmed to rough discs.They exhibit great potential for the study of the origin of primordial art and the development of ancient cultures and provide important data for studying behavioral options adopted by hominids in SDG area.In addition,they bear important implications for the origin of modern humans in East Asia.

  4. Guided self-assembly of magnetic beads for biomedical applications

    CERN Document Server

    Gusenbauer, Markus; Reichel, Franz; Exl, Lukas; Bance, Simon; Fischbacher, Johann; Özelt, Harald; Kovacs, Alexander; Brandl, Martin; Schrefl, Thomas

    2013-01-01

    Micromagnetic beads are widely used in biomedical applications for cell separation, drug delivery, and hypothermia cancer treatment. Here we propose to use self-organized magnetic bead structures which accumulate on fixed magnetic seeding points to isolate circulating tumor cells. The analysis of circulating tumor cells is an emerging tool for cancer biology research and clinical cancer management including the detection, diagnosis and monitoring of cancer. Microfluidic chips for isolating circulating tumor cells use either affinity, size or density capturing methods. We combine multiphysics simulation techniques to understand the microscopic behavior of magnetic beads interacting with Nickel accumulation points used in lab-on-chip technologies. Our proposed chip technology offers the possibility to combine affinity and size capturing with special antibody-coated bead arrangements using a magnetic gradient field created by Neodymium Iron Boron permanent magnets. The multiscale simulation environment combines ...

  5. Guided self-assembly of magnetic beads for biomedical applications

    Science.gov (United States)

    Gusenbauer, Markus; Nguyen, Ha; Reichel, Franz; Exl, Lukas; Bance, Simon; Fischbacher, Johann; Özelt, Harald; Kovacs, Alexander; Brandl, Martin; Schrefl, Thomas

    2014-02-01

    Micromagnetic beads are widely used in biomedical applications for cell separation, drug delivery, and hyperthermia cancer treatment. Here we propose to use self-organized magnetic bead structures which accumulate on fixed magnetic seeding points to isolate circulating tumor cells. The analysis of circulating tumor cells is an emerging tool for cancer biology research and clinical cancer management including the detection, diagnosis and monitoring of cancer. Microfluidic chips for isolating circulating tumor cells use either affinity, size or density capturing methods. We combine multiphysics simulation techniques to understand the microscopic behavior of magnetic beads interacting with soft magnetic accumulation points used in lab-on-chip technologies. Our proposed chip technology offers the possibility to combine affinity and size capturing with special antibody-coated bead arrangements using a magnetic gradient field created by Neodymium Iron Boron permanent magnets. The multiscale simulation environment combines magnetic field computation, fluid dynamics and discrete particle dynamics.

  6. Polymer-Coated Graphene Aerogel Beads and Supercapacitor Application.

    Science.gov (United States)

    Ouyang, An; Cao, Anyuan; Hu, Song; Li, Yanhui; Xu, Ruiqiao; Wei, Jinquan; Zhu, Hongwei; Wu, Dehai

    2016-05-01

    Graphene aerogels are highly porous materials with many energy and environmental applications; tailoring the structure and composition of pore walls within the aerogel is the key to those applications. Here, by freeze casting the graphene oxide sheets, we directly fabricated freestanding porous graphene beads containing radially oriented through channels from the sphere center to its surface. Furthermore, we introduced pseudopolymer to make reinforced, functional composite beads with a unique pore morphology. We showed that polymer layers can be coated smoothly on both sides of the pore walls, as well as on the junctions between adjacent pores, resulting in uniform polymer-graphene-polymer sandwiched structures (skeletons) throughout the bead. These composite beads significantly improved the electrochemical properties, with specific capacitances up to 669 F/g and good cyclic stability. Our results indicate that controlled fabrication of homogeneous hierarchical structures is a potential route toward high performance composite electrodes for various energy applications.

  7. 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.

  8. Biocompatibility, degradability, bioactivity and osteogenesis of mesoporous/macroporous scaffolds of mesoporous diopside/poly(l-lactide) composite

    OpenAIRE

    Liu, Zhulin; Ji, Jiajin; Tang, Songchao; Qian, Jun; Yan, Yonggang; Yu, Baoqing; Su, Jiacan; Wei, Jie

    2015-01-01

    Bioactive mesoporous diopside (m-DP) and poly(l-lactide) (PLLA) composite scaffolds with mesoporous/macroporous structure were prepared by the solution-casting and particulate-leaching method. The results demonstrated that the degradability and bioactivity of the mesoporous/macroporous scaffolds were significantly improved by incorporating m-DP into PLLA, and that the improvement was m-DP content-dependent. In addition, the scaffolds containing m-DP showed the ability to neutralize acidic deg...

  9. Formulation and characterization of rifabutin loaded floating gellan gum beads

    OpenAIRE

    2011-01-01

    Rifabutin loaded floating gellan gum beads were prepared by Ca++ induced ionotropic gelation in acidic medium by drop wise addition of gellan gum dispersion containing drug and gas-generating agent. The prepared beads were evaluated for in vitro characterization and in vivo Helicobacter pylori clearance efficiency following repeated oral administration to H. pylori infected albino rats. Live cell staining of stomach homogenates of H. pylori infected animals treated with rifabutin showed prono...

  10. Ferrite bead effect on Class-D amplifier audio quality

    OpenAIRE

    Haddad, Kevin El; Mrad, Roberto; Morel, Florent; Pillonnet, Gael; Vollaire, Christian; Nagari, Angelo

    2014-01-01

    International audience; This paper studies the effect of ferrite beads on the audio quality of Class-D audio amplifiers. This latter is a switch-ing circuit which creates high frequency harmonics. Generally, a filter is used at the amplifier output for the sake of electro-magnetic compatibility (EMC). So often, in integrated solutions, this filter contains ferrite beads which are magnetic components and present nonlinear behavior. Time domain measurements and their equivalence in frequency do...

  11. Cellulose nanomaterials review: structure, properties and nanocomposites

    Science.gov (United States)

    Robert J. Moon; Ashlie Martini; John Nairn; John Simonsen; Jeff Youngblood

    2011-01-01

    This critical review provides a processing-structure-property perspective on recent advances in cellulose nanoparticles and composites produced from them. It summarizes cellulose nanoparticles in terms of particle morphology, crystal structure, and properties. Also described are the self-assembly and rheological properties of cellulose nanoparticle suspensions. The...

  12. Bioengineering cellulose-hemicellulose networks in plants

    NARCIS (Netherlands)

    Obembe, O.

    2006-01-01

    The interactions between cellulose and hemicellulose in the cell walls are important in the industrial application of the cellulose (natural) fibres. We strive to modify these interactions (i) by interfering with cellulose biosynthesis and (ii) by direct interference of the

  13. Adsorption and desorption of cellulose derivatives

    NARCIS (Netherlands)

    Hoogendam, C.W.

    1998-01-01

    Cellulose derivatives, in particular carboxymethyl cellulose (CMC) are used in many (industrial) applications. The aim of this work is to obtain insight into the adsorption mechanism of cellulose derivatives on solid-liquid interfaces.

    In chapter 1

  14. Adsorption and desorption of cellulose derivatives.

    NARCIS (Netherlands)

    Hoogendam, C.W.

    1998-01-01

    Cellulose derivatives, in particular carboxymethyl cellulose (CMC) are used in many (industrial) applications. The aim of this work is to obtain insight into the adsorption mechanism of cellulose derivatives on solid-liquid interfaces.In chapter 1 of this thesis we discuss some appl

  15. Ionic Liquids and Cellulose: Dissolution, Chemical Modification and Preparation of New Cellulosic Materials

    Directory of Open Access Journals (Sweden)

    Mehmet Isik

    2014-07-01

    Full Text Available Due to its abundance and a wide range of beneficial physical and chemical properties, cellulose has become very popular in order to produce materials for various applications. This review summarizes the recent advances in the development of new cellulose materials and technologies using ionic liquids. Dissolution of cellulose in ionic liquids has been used to develop new processing technologies, cellulose functionalization methods and new cellulose materials including blends, composites, fibers and ion gels.

  16. Impact of Biofield Treatment on Chemical and Thermal Properties of Cellulose and Cellulose Acetate

    OpenAIRE

    Trivedi, Mahendra Kumar

    2015-01-01

    Cellulose being an excellent biopolymer has cemented its place firmly in many industries as a coating material, textile, composites, and biomaterial applications. In the present study, we have investigated the effect of biofield treatment on physicochemical properties of cellulose and cellulose acetate. The cellulose and cellulose acetate were exposed to biofield and further the chemical and thermal properties were investigated. X-ray diffraction study asserted that the biofield treatment did...

  17. Physicotechnical, spectroscopic and thermogravimetric properties of powdered cellulose and microcrystalline cellulose derived from groundnut shells

    OpenAIRE

    Chukwuemeka P. Azubuike; Jimson O. Odulaja; Augustine O Okhamafe

    2012-01-01

    α-Cellulose and microcrystalline cellulose powders, derived from agricultural waste products, that have for thepharmaceutical industry, desirable physical (flow) properties were investigated. α–Cellulose (GCN) wasextracted from groundnut shell (an agricultural waste product) using a non-dissolving method based oninorganic reagents. Modification of this α -cellulose was carried out by partially hydrolysing it with 2Nhydrochloric acid under reflux to obtain microcrystalline cellulose (MCGN). Th...

  18. Atomic force microscopy study of cellulose surface interaction controlled by cellulose binding domains

    OpenAIRE

    Nigmatullin, R.; Lovitt, R.; Wright, C; Linder, M.; Nakari-Setälä, T; Gama, F. M.

    2004-01-01

    Colloidal probe microscopy has been used to study the interaction between model cellulose surfaces and the role of cellulose binding domain (CBD), peptides specifically binding to cellulose, in interfacial interaction of cellulose surfaces modified with CBDs. The interaction between pure cellulose surfaces in aqueous electrolyte solution is dominated by double layer repulsive forces with the range and magnitude of the net force dependent on electrolyte concentration. AFM imaging reve...

  19. A Macroporous TiO2 Oxygen Sensor Fabricated Using Anodic Aluminium Oxide as an Etching Mask

    Directory of Open Access Journals (Sweden)

    Sheng-Po Wu

    2010-01-01

    Full Text Available An innovative fabrication method to produce a macroporous Si surface by employing an anodic aluminium oxide (AAO nanopore array layer as an etching template is presented. Combining AAO with a reactive ion etching (RIE processes, a homogeneous and macroporous silicon surface can be effectively configured by modulating AAO process parameters and alumina film thickness, thus hopefully replacing conventional photolithography and electrochemical etch methods. The hybrid process integration is considered fully CMOS compatible thanks to the low-temperature AAO and CMOS processes. The gas-sensing characteristics of 50 nm TiO2 nanofilms deposited on the macroporous surface are compared with those of conventional plain (or non-porous nanofilms to verify reduced response noise and improved sensitivity as a result of their macroporosity. Our experimental results reveal that macroporous geometry of the TiO2 chemoresistive gas sensor demonstrates 2-fold higher (~33% improved sensitivity than a non-porous sensor at different levels of oxygen exposure. In addition, the macroporous device exhibits excellent discrimination capability and significantly lessened response noise at 500 °C. Experimental results indicate that the hybrid process of such miniature and macroporous devices are compatible as well as applicable to integrated next generation bio-chemical sensors.

  20. A macroporous TiO2 oxygen sensor fabricated using anodic aluminium oxide as an etching mask.

    Science.gov (United States)

    Lu, Chih-Cheng; Huang, Yong-Sheng; Huang, Jun-Wei; Chang, Chien-Kuo; Wu, Sheng-Po

    2010-01-01

    An innovative fabrication method to produce a macroporous Si surface by employing an anodic aluminium oxide (AAO) nanopore array layer as an etching template is presented. Combining AAO with a reactive ion etching (RIE) processes, a homogeneous and macroporous silicon surface can be effectively configured by modulating AAO process parameters and alumina film thickness, thus hopefully replacing conventional photolithography and electrochemical etch methods. The hybrid process integration is considered fully CMOS compatible thanks to the low-temperature AAO and CMOS processes. The gas-sensing characteristics of 50 nm TiO(2) nanofilms deposited on the macroporous surface are compared with those of conventional plain (or non-porous) nanofilms to verify reduced response noise and improved sensitivity as a result of their macroporosity. Our experimental results reveal that macroporous geometry of the TiO(2) chemoresistive gas sensor demonstrates 2-fold higher (∼33%) improved sensitivity than a non-porous sensor at different levels of oxygen exposure. In addition, the macroporous device exhibits excellent discrimination capability and significantly lessened response noise at 500 °C. Experimental results indicate that the hybrid process of such miniature and macroporous devices are compatible as well as applicable to integrated next generation bio-chemical sensors.

  1. Preparation of Bio-beads and Their Atrazine Degradation Characteristics

    Institute of Scientific and Technical Information of China (English)

    BI Hai-tao; ZHANG Lan-ying; LIU Na; ZHU Bo-lin

    2011-01-01

    Screened atrazine-mineralizing bacterium-Pseudomonas W4 was embedded inside an improved PVAH3BO3 embedment matrix to make bio-beads to degrade atrazine. The atrazine degradation characteristics were studied. The preparation procedure of bio-beads was as follows: (1) preparing a mixture of 100, 12.5, 10, 1.5 and 1 g/L PVA, bentonite(Ca), activated carbon powder, sodium alginate and centrifuged Pseudomonas W4 bacterium, respectively; (2) the mixture was dropped into a gently stirred cross linker solution(pH=6.7) and cured at 10 ℃ for 24 h.The optimal atrazine degradation conditions by bio-beads were as follows: pH=7, the auxiliary carbon source was glucose, and the concentration of glucose was greater than 325 mg/L. The bio-beads demonstrated stronger tolerance ability than the free microorganism to the increase of PCBs, hydrogen ion and hydroxide ion. SEM images show the uniform distribution of the microorganism inside bio-beads and the porous cross-linked structure of bio-beads which provides excellent mass transfer capacity.

  2. Physicochemical Characterization of Alginate Beads Containing Sugars and Biopolymers

    Directory of Open Access Journals (Sweden)

    Tatiana Aguirre Calvo

    2016-01-01

    Full Text Available Alginate hydrogels are suitable for the encapsulation of a great variety of biomolecules. Several alternatives to the conventional alginate formulation are being studied for a broad range of biotechnological applications; among them the addition of sugars and biopolymers arises as a good and economic strategy. Sugars (trehalose and β-cyclodextrin, a cationic biopolymer (chitosan, an anionic biopolymer (pectin, and neutral gums (Arabic, guar, espina corona, and vinal gums provided different characteristics to the beads. Here we discuss the influence of beads composition on several physicochemical properties, such as size and shape, analyzed through digital image analysis besides both water content and activity. The results showed that the addition of a second biopolymer, β-CD, or trehalose provoked more compact beads, but the fact that they were compact not necessarily implies a concomitant increase in their circularity. Espina corona beads showed the highest circularity value, being useful for applications which require a controlled and high circularity, assuring quality control. Beads with trehalose showed lower water content than the rest of the system, followed by those containing galactomannans (espina corona, vinal, and guar gums, revealing polymer structure effects. A complete characterization of the beads was performed by FT-IR, assigning the characteristics bands to each individual component.

  3. Three-dimensional ordered macroporous platinum-based electrode for methanol oxidation

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    In this paper, three-dimensional ordered macroporous platinum catalysts with high real surface area were synthesized using the inverted colloidal crystals template technique and have been employed for the electrooxidation of methanol. The morphology and electrocatalytic behavior of the porous Pt electrodes were investigated with atomic force microscopy and electrochemical techniques. For the same amount of Pt deposited, the real surface areas of the electrodes are 9.16 and 8.00 cm2 for the porous electrodes with pore size of 320 and 500 nm respectively, which are more than 5 times larger than the directly deposited Pt electrode (1.4 cm2). The pore size effect on the methanol electrooxidation was investigated by testing low concentration solution of methanol and porous materials with different pore sizes. The synthesized macroporous Pt electrode shows high stability toward the electrooxidation of methanol and is promising for the direct methanol fuel cell.

  4. Ordered macroporous platinum electrode and enhanced mass transfer in fuel cells using inverse opal structure.

    Science.gov (United States)

    Kim, Ok-Hee; Cho, Yong-Hun; Kang, Soon Hyung; Park, Hee-Young; Kim, Minhyoung; Lim, Ju Wan; Chung, Dong Young; Lee, Myeong Jae; Choe, Heeman; Sung, Yung-Eun

    2013-01-01

    Three-dimensional, ordered macroporous materials such as inverse opal structures are attractive materials for various applications in electrochemical devices because of the benefits derived from their periodic structures: relatively large surface areas, large voidage, low tortuosity and interconnected macropores. However, a direct application of an inverse opal structure in membrane electrode assemblies has been considered impractical because of the limitations in fabrication routes including an unsuitable substrate. Here we report the demonstration of a single cell that maintains an inverse opal structure entirely within a membrane electrode assembly. Compared with the conventional catalyst slurry, an ink-based assembly, this modified assembly has a robust and integrated configuration of catalyst layers; therefore, the loss of catalyst particles can be minimized. Furthermore, the inverse-opal-structure electrode maintains an effective porosity, an enhanced performance, as well as an improved mass transfer and more effective water management, owing to its morphological advantages.

  5. Enhanced Electrocatalytic Activity of Pt/3D Hierarchical Bimodal Macroporous Carbon Nanospheres.

    Science.gov (United States)

    Balgis, Ratna; Widiyastuti, W; Ogi, Takashi; Okuyama, Kikuo

    2017-07-19

    Proton exchange membrane fuel cells require electrocatalysts with a high platinum (Pt) loading, large active surface area, and favorable hydrodynamic profile for practical applications. Here, we report the design of three-dimensional hierarchical bimodal macroporous carbon nanospheres with an interconnected pore system, which are applied as an electrocatalyst support. Carbon-supported Pt (Pt/C) catalysts were prepared by aerosol spray pyrolysis followed by microwave chemical deposition. The hierarchical porous structures not only increased the dispersion of Pt nanoparticles but also improved catalytic performance. A hierarchical bimodal macroporous Pt/C catalyst with a mixture of 30 and 120 nm size pores showed the best performance. The electrochemical surface area and mass activity values of this support were 96 m(2) g(-1)-Pt and 378 mA mg(-1)-Pt, respectively at a Pt loading of 15 wt %.

  6. Effect of macroporous adsorption resin-membrane bioreactor hybrid system against fouling for municipal wastewater treatment.

    Science.gov (United States)

    Chen, Weiwei; Luo, Jing; Cao, Ruyi; Li, Yuting; Liu, Jinrong

    2017-01-01

    Membrane bioreactor (MBR) displays significant advantages in effluent quality, sludge production, footprint, and operation. However, membrane fouling limits the application of MBR. This study investigated membrane fouling in a macroporous adsorption resin-membrane bioreactor hybrid system established by adding macroporous adsorption resin (MAR) into MBR. MAR addition increased the critical flux by 27.97%, indicating that membrane fouling was successfully mitigated. Consequently, comparative experiments were designed to analyze the pathway. MAR addition mitigated external fouling development and improved mixed liquor characteristics, thereby mitigating gel layer formation and sludge floc deposition on the membrane surface. MAR effectively reduced the supernatant viscosity and dissolved COD by adsorbing soluble microbial products. Sludge production decreased because the sludge activity in MAR-MBR was inhibited. The fouled MAR could be regenerated effectively by deionized water and chemical cleaning. This work demonstrated the feasibility of using MAR-MBR to mitigate fouling in municipal wastewater treatment. Copyright © 2016 Elsevier Ltd. All rights reserved.

  7. Thermoresponsive composite hydrogels with aligned macroporous structure by ice-templated assembly.

    Science.gov (United States)

    Bai, Hao; Polini, Alessandro; Delattre, Benjamin; Tomsia, Antoni P

    2013-10-26

    Natural tissues, such as bone, tendon, and muscle, have well defined hierarchical structures, which are crucial for their biological and mechanical functions. However, mimicking these structural features still remains a great challenge. In this study, we use ice-templated assembly and UV-initiated cryo-polymerization to fabricate a novel kind of composite hydrogel which have both aligned macroporous structure at micrometer scale and a nacre-like layered structure at nanoscale. Such hydrogels are macroporous, thermoresponsive, and exhibit excellent mechanical performance (tough and high stretchable), attractive properties that are of significant impact on the wide applications of composite hydrogels, especially as tissue-engineering scaffolds. The fabrication method in this study including freeze-casting and cryo-polymerization can also be applied to other materials, which makes it promising for designing and developing smart and multifunctional composite hydrogels with hierar chical structures.

  8. Macroporous resin purification of peptides with umami taste from soy sauce.

    Science.gov (United States)

    Zhuang, Mingzhu; Zhao, Mouming; Lin, Lianzhu; Dong, Yi; Chen, Huiping; Feng, Mengying; Sun-Waterhouse, Dongxiao; Su, Guowan

    2016-01-01

    In this study, the performance and separation characteristics of four macroporous resins for purifying umami peptides from soy sauce were examined. Results showed that the resins could separate the peptides of soy sauce, and the particle diffusion kinetics model was suitable for describing the whole exothermic (ΔH resins, while the pseudo-second-order kinetics model accurately described the XAD-16 and HP-2 MGL resins. Furthermore, the adsorption processes of the peptides followed the Freundlich model. The XAD-16 resin was the most effective resin for the enrichment of peptides due to its high adsorption and total desorption capacities. Interestingly, the umami peptides were enriched in the deionized water fraction. This study provides new insights into exploring performance and separation characteristics of macroporous resins on soy sauce, and indicated that peptide may be the contributor to the umami taste in Chinese soy sauce.

  9. Bioethanol production by reusable Saccharomyces cerevisiae immobilized in a macroporous monolithic hydrogel matrices.

    Science.gov (United States)

    Mulko, Lucinda; Rivarola, Claudia R; Barbero, Cesar A; Acevedo, Diego F

    2016-09-10

    Performance of yeasts on industrial processes can be dramatically improved by immobilization of the biocatalyst. The immobilization of Saccharomyces cerevisiae inside monolithic macroporous hydrogels were produced by in-situ polymerization of acrylamide around a live yeast suspension under cryogelation conditions. Preculture of the yeasts was not necessary and this innovative and simple procedure is amenable to scaling-up to industrial production. The yeasts were efficiently retained in monolithic hydrogels, presenting excellent mechanical properties and high cell viability. Macroporous hydrogels showed a fast mass transport allowing the hydrogel-yeast complexes achieved similar ethanol yield and productivity than free yeasts, which is larger than those reached with yeasts immobilized in compact hydrogels. Moreover, the same yeasts were able to maintain its activity by up to five reaction cycles with a cell single batch during fermentation reactions.

  10. Synthesis and Textural Characterization of Mesoporous and Meso-/Macroporous Silica Monoliths Obtained by Spinodal Decomposition

    Directory of Open Access Journals (Sweden)

    Anne Galarneau

    2016-04-01

    Full Text Available Silica monoliths featuring either mesopores or flow-through macropores and mesopores in their skeleton are prepared by combining spinodal phase separation and sol-gel condensation. The macroporous network is first generated by phase separation in acidic medium in the presence of polyethyleneoxides while mesoporosity is engineered in a second step in alkaline medium, possibly in the presence of alkylammonium cations as surfactants. The mesoporous monoliths, also referred as aerogels, are obtained in the presence of alkylpolyethylene oxides in acidic medium without the use of supercritical drying. The impact of the experimental conditions on pore architecture of the monoliths regarding the shape, the ordering, the size and the connectivity of the mesopores is comprehensively discussed based on a critical appraisal of the different models used for textural analysis.

  11. Preparation of spherical macroporous poly(lactic-co-glycolic acid) for bone tissue regeneration.

    Science.gov (United States)

    Bian, Chunhui; Lin, Huiming; Li, Xiaofeng; Ma, Jie; Jiang, Pingping; Qu, Fengyu

    2015-02-01

    Spherical macroporous poly(lactic-co-glycolic acid) (PLGA) has been synthesised using an emulsion method. Polyvinyl alcohol and Pluronic F127 have been used as dispersing and porogen agent, respectively. The diameter of the spherical PLGA is about 20 μm and the pore size of the PLGA macroporous is about 2-2.5 μm observed by scanning electron microscopy. After immersing in simulated body fluid, the PLGA materials can induce the formation of hydroxyapatite (HAP) on their surface. The HAP-PLGA has been obtained and used as the host for drug release. Furthermore, the drug-loaded samples possess the various drug release performance by adjusting the thickness of the HAP layer. This highly satisfied composite material is expected to be promising in the applications in tissue regeneration engineering.

  12. Development of macropore arrays in silicon and related technologies for X-ray imaging applications

    OpenAIRE

    Badel, Xavier

    2003-01-01

    Digital devices have started to replace photographic film inX-ray imaging applications. As compared to photographic films,these devices are more convenient to obtain images and tohandle, treat and store these images. The goal of the presentstudy is to develop macropore arrays and related silicontechnologies in order to fabricate X-ray imaging detectors formedical applications, and in particular for dentistry. Althougha few detectors are already available on the market, theirperformances, such...

  13. Hierarchically microporous/macroporous scaffold of magnesium-calcium phosphate for bone tissue regeneration.

    Science.gov (United States)

    Wei, Jie; Jia, Junfeng; Wu, Fan; Wei, Shicheng; Zhou, Huanjun; Zhang, Hongbo; Shin, Jung-Woog; Liu, Changsheng

    2010-02-01

    Hierarchically 3D microporous/macroporous magnesium-calcium phosphate (micro/ma-MCP) scaffolds containing magnesium ammonium phosphate hexahydrate [NH(4)MgPO(4).6H(2)O] and hydroxyapatite [Ca(10)(PO(4))(6)(OH)(2)] were fabricated from cement utilizing leaching method in the presence of sodium chloride (NaCl) particles and NaCl saturated water solution. NaCl particles produced macroporosity, and NaCl solution acted as both cement liquid and porogens, inducing the formation of microporosity. The micro/ma-MCP scaffolds with porosities varied from 52 to 78% showed well interconnected and open macropores with the sizes of 400-500 microm, and degradation of the scaffolds was significantly enhanced in Tris-HCl solution compared with macroporous MCP (ma-MCP) and corresponding calcium phosphate cement (CPC) scaffolds. Cell attachment and proliferation of MG(63) on micro/ma-MCP were significantly better than ma-MCP and CPC scaffolds because of the presence of microporosity, which enhanced the surface area of the scaffolds. Moreover, the alkaline phosphatase (ALP) activity of the MG(63) cells on micro/ma-MCP was significantly higher than ma-MCP and CPC scaffolds at 7 days, and the MG(63) cells with normal phenotype spread well and formed confluent layers across the macroporous walls of the micro/ma-MCP scaffolds. Histological evaluation confirmed that the micro/ma-MCP scaffolds improved the efficiency of new bone regeneration, and exhibited excellent biocompatibility, biodegradability and faster and more effective osteogenesis in vivo.

  14. Adsorption of Monobutyl Phthalate from Aqueous Phase onto Two Macroporous Anion-Exchange Resins

    OpenAIRE

    Zhengwen Xu; Yunlong Zhao; Jing Shi; Jiangang Lu; Ling Cheng; Mindong Chen

    2014-01-01

    As new emerging pollutants, phthalic acid monoesters (PAMs) pose potential ecological and human health risks. In the present study, adsorption performance of monobutyl phthalate (MBP) onto two macroporous base anion-exchange resins (D-201 and D-301) was discussed. It was found that the adsorption isotherms were best fitted by the Langmuir equation while the adsorption kinetics were well described by pseudo-first-order model. Analyses of sorption isotherms and thermodynamics proved that the ad...

  15. Monodisperse spherical meso-macroporous silica particles: Synthesis and adsorption of biological macromolecules

    Science.gov (United States)

    Stovpiaga, E. Yu.; Grudinkin, S. A.; Kurdyukov, D. A.; Kukushkina, Yu. A.; Nashchekin, A. V.; Sokolov, V. V.; Yakovlev, D. R.; Golubev, V. G.

    2016-11-01

    Monodispersed spherical silica particles, including large mesopores (over 10 nm) and macropores (up to 100 nm) were obtained by chemical etching in an autoclave. A method for introducing globular protein myoglobin molecules into the pores is developed. The method of filling is based on a high adsorption capacity of the developed internal pore structure of the particles. The structure and adsorption properties of the materials are studied.

  16. Foaming of Ethyl Hydroxyethyl Cellulose

    OpenAIRE

    Carrillo Agilera, Marc

    2015-01-01

    The current depletion of petroleum resources together with environmental issues have led to new approaches in plastic manufacturing. This trend involves using ecofriendly materials coming from renewable resources. Good candidates for this, due to their properties and availability, are the cellulose derivatives. Some of them, such as hydroxypropyl methylcellulose (HPMC), showed in previous studies a promising behavior when making polymeric foams. Unfortunately, the corresponding...

  17. Cellulose nanomaterials review: structure, properties and nanocomposites.

    Science.gov (United States)

    Moon, Robert J; Martini, Ashlie; Nairn, John; Simonsen, John; Youngblood, Jeff

    2011-07-01

    This critical review provides a processing-structure-property perspective on recent advances in cellulose nanoparticles and composites produced from them. It summarizes cellulose nanoparticles in terms of particle morphology, crystal structure, and properties. Also described are the self-assembly and rheological properties of cellulose nanoparticle suspensions. The methodology of composite processing and resulting properties are fully covered, with an emphasis on neat and high fraction cellulose composites. Additionally, advances in predictive modeling from molecular dynamic simulations of crystalline cellulose to the continuum modeling of composites made with such particles are reviewed (392 references).

  18. Competitive adsorption of a phthalate esters mixture by chitosan bead and alpha-cyclodextrin-linked chitosan bead.

    Science.gov (United States)

    Chung, Ying-Chien; Chen, Chih-Yu

    2009-12-01

    The competitive adsorption effect by chitosan bead and alpha-cyclodextrin-linked chitosan bead on a mixture of six phthalate esters (PAEs) was investigated. The adsorption efficiency of short-chain hydrophilic PAEs was reduced when long-chain hydrophobic PAEs co-existed in the solution. Moreover, the adsorption efficiency of adsorbents for PAE is correlated to the distribution ratio (Kd), which shows that the Kd of hydrophobic PAEs is higher than that of hydrophilic PAEs. Both chitosan bead and alpha-cyclodextrin-linked chitosan bead exhibit the same phenomenon. The effect of alpha-cyclodextrin (CD)-linked chitosan bead is more significant compared with that of chitosan bead. Furthermore, it is observed that both adsorbents spontaneously adsorb PAEs by free energy (deltaG0), but the hydrophilic PAE co-existing with DMP (dimethyl phthalate) results in less entropy (deltaS0) change compared with a hydrophobic PAE co-existing with DMP. In a continuous system to treat a PAE mixture, hydrophobic PAE shows a higher breakthrough capacity than hydrophilic PAE. Moreover, the competitive adsorption results in the laboratory were comparable with those in field studies.

  19. Current-voltage characteristics in macroporous silicon/SiOx/SnO2:F heterojunctions.

    Science.gov (United States)

    Garcés, Felipe A; Urteaga, Raul; Acquaroli, Leandro N; Koropecki, Roberto R; Arce, Roberto D

    2012-07-25

    We study the electrical characteristics of macroporous silicon/transparent conductor oxide junctions obtained by the deposition of fluorine doped-SnO2 onto macroporous silicon thin films using the spray pyrolysis technique. Macroporous silicon was prepared by the electrochemical anodization of a silicon wafer to produce pore sizes ranging between 0.9 to 1.2 μm in diameter. Scanning electronic microscopy was performed to confirm the pore filling and surface coverage. The transport of charge carriers through the interface was studied by measuring the current-voltage curves in the dark and under illumination. In the best configuration, we obtain a modest open-circuit voltage of about 70 mV and a short-circuit current of 3.5 mA/cm2 at an illumination of 110 mW/cm2. In order to analyze the effects of the illumination on the electrical properties of the junction, we proposed a model of two opposing diodes, each one associated with an independent current source. We obtain a good accordance between the experimental data and the model. The current-voltage curves in illuminated conditions are well fitted with the same parameters obtained in the dark where only the photocurrent intensities in the diodes are free parameters.

  20. Macroporous Composite Cryogels with Embedded Polystyrene Divinylbenzene Microparticles for the Adsorption of Toxic Metabolites from Blood

    Directory of Open Access Journals (Sweden)

    Tanja Eichhorn

    2013-01-01

    Full Text Available Composite monolithic adsorbents were prepared by the incorporation of neutral polystyrene divinylbenzene (PS-DVB microparticles into macroporous polymer structures produced by cryogelation of agarose or poly(vinyl alcohol. The composite materials exhibited excellent flow-through properties. Scanning electron microscopy of the composite cryogels revealed that the microparticles were covered by thin films of poly(vinyl alcohol or agarose and thus were withheld in the monolith structure. Plain PS-DVB microparticles showed efficient adsorption of albumin-bound toxins related to liver failure (bilirubin and cholic acid and of cytokines (tumor necrosis factor-alpha and interleukin-6. The rates of adsorption and the amount of adsorbed factors were lower for the embedded microparticles as compared to the parent PS-DVB microparticles, indicating the importance of the accessibility of the adsorbent pores. Still, the macroporous composite materials showed efficient adsorption of albumin-bound toxins related to liver failure as well as efficient binding of cytokines, combined with good blood compatibility. Thus, the incorporation of microparticles into macroporous polymer structures may provide an option for the development of adsorption modules for extracorporeal blood purification.

  1. Fully Accessible Ag Nanoparticles within Three-dimensionally Ordered Macroporous SiO2

    Institute of Scientific and Technical Information of China (English)

    邬泉周; 尹强; 廖菊芳; 邓景衡; 李玉光

    2005-01-01

    A multi-step process was used for preparation of three-dimensionally ordered macroporous (3DOM) SiO2, in which fully accessible Ag nanoparticles are incorporated. The method involves the processes of assembly of polystyrene colloidal crystal, preparation of 3DOM SiO2, and incorporation of Ag nanoparticles within 3DOM SiO2 through in situ Tollens' reaction. XRD, SEM and EDXS determination show that the Ag particles deposited on the macroporous walls in nano dimension. The results indicate that lower concentration of silver ammoniate and for-maldehyde in the solution is favorable for forming a very narrow size distribution and uniform shape of nanoparticles. However, the higher the concentration of the solution and the more the loading times, the larger the possibility to form un-uniform particles. Ag nanoparticles can be sintered into larger and spheral particles by calcination at 600℃, but can resist sintering owing to their high dispersivity when loading amount is small. The study provided a simple approach to tailor Ag/3DOM SiO2 composite materials with desired morphology and size of Ag particles within the macropores.

  2. Separation of salvianic acid A from the fermentation broth of engineered Escherichia coli using macroporous resins.

    Science.gov (United States)

    Bai, Chen-Long; Zhao, Guang-Rong

    2015-08-01

    Salvianic acid A (also known as danshensu) is a plant-derived polyphenolic acid, and has a variety of physiological and pharmacological activities. Our laboratory previously constructed an unprecedented artificial biosynthetic pathway in Escherichia coli and established the fermentation process to produce salvianic acid A. Here, we developed an efficient method for separating salvianic acid A from the fermentation broth of engineered Escherichia coli by macroporous resins. Among ten tested macroporous resins, the static and dynamic adsorption/desorption experiments demonstrated that X5 resin was the best to separate salvianic acid A from fermentation broth. Other parameters during static and dynamic procedures were also investigated. Under the optimum separation conditions, the average adsorption capacity of SAA were 10.66±0.54 mg/g dry resin and the desorption ratio was 85.6±4.1%. The purity and recovery yield of salvianic acid A in the final dry product were 90.2±1.5 and 81.5±2.3%, respectively. The results show that adsorption separation with macroporous resin X5 was an efficient method to prepare salvianic acid A from fermentation broth. This work will benefit the development and application of plant-derived salvianic acid A and its derivatives. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Human umbilical cord stem cell encapsulation in novel macroporous and injectable fibrin for muscle tissue engineering

    Science.gov (United States)

    Liu, Jun; Xu, Hockin H.K.; Zhou, Hongzhi; Weir, Michael D.; Chen, Qianming; Trotman, Carroll Ann

    2012-01-01

    There has been little research on the seeding of human umbilical cord mesenchymal stem cells (hUCMSCs) in three-dimensional scaffolds for muscle tissue engineering. The objectives of this study were: (i) to seed hUCMSCs in a fibrin hydrogel containing fast-degradable microbeads (dMBs) to create macropores to enhance cell viability; and (ii) to investigate the encapsulated cell proliferation and myogenic differentiation for muscle tissue engineering. Mass fractions of 0–80% of dMBs were tested, and 35% of dMBs in fibrin was shown to avoid fibrin shrinkage while creating macropores and promoting cell viability. This construct was referred to as “dMB35”. Fibrin without dMBs was termed “dMB0”. Microbead degradation created macropores in fibrin and improved cell viability. The percentage of live cells in dMB35 reached 91% at 16 days, higher than the 81% in dMB0 (p muscle tissue engineering applications. PMID:22902812

  4. Preparation of ZIF-8 membranes supported on macroporous carbon tubes via a dipcoating-rubbing method

    Science.gov (United States)

    Kong, Lingyin; Zhang, Xiongfu; Liu, Haiou; Wang, Tonghua; Qiu, Jieshan

    2015-02-01

    In the present work, a new dipcoating-rubbing method (DCRM) was developed to seed the surface of a macroporous carbon tube with a mixture of graphite and ZIF-8 nanoparticles. A continuous and low-defect ZIF-8 membrane was well formed on the seeded carbon tube by solvothermal growth. The DCRM involved a two-step process including first dipcoating a thin layer of the composite of graphite and ZIF-8 nanoparticles on the carbon surface and then rubbing the layer to form a stable seed layer. The graphite in the composite acting as binding agent could have two functions: (1) anchoring the ZIF-8 seeds onto the carbon surface; (2) smoothing the coarse surface of the macroporous carbon tube, thus forming a high quality ZIF-8 membrane. The as-prepared membrane was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and single gas permeation and was proved to be continuous and low-defect. The ideal selectivity of H2/CH4 is 7.9 with a H2 permeance of 7.15×10-8 mol Pa-1 s-1 m-2, which is higher than its corresponding Knudsen diffusion value. We could therefore expect the ZIF-8 membrane supported on macroporous tubular carbon to achieve a high selectivity of H2 over CH4 through a molecular sieving effect.

  5. 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.

  6. Structure and engineering of celluloses.

    Science.gov (United States)

    Pérez, Serge; Samain, Daniel

    2010-01-01

    This chapter collates the developments and conclusions of many of the extensive studies that have been conducted on cellulose, with particular emphasis on the structural and morphological features while not ignoring the most recent results derived from the elucidation of unique biosynthetic pathways. The presentation of structural and morphological data gathered together in this chapter follows the historical development of our knowledge of the different structural levels of cellulose and its various organizational levels. These levels concern features such as chain conformation, chain polarity, chain association, crystal polarity, and microfibril structure and organization. This chapter provides some historical landmarks related to the evolution of concepts in the field of biopolymer science, which parallel the developments of novel methods for characterization of complex macromolecular structures. The elucidation of the different structural levels of organization opens the way to relating structure to function and properties. The chemical and biochemical methods that have been developed to dissolve and further modify cellulose chains are briefly covered. Particular emphasis is given to the facets of topochemistry and topoenzymology where the morphological features play a key role in determining unique physicochemical properties. A final chapter addresses what might be considered tomorrow's goal in amplifying the economic importance of cellulose in the context of sustainable development. Selected examples illustrate the types of result that can be obtained when cellulose fibers are no longer viewed as inert substrates, and when the polyhydroxyl nature of their surfaces, as well as their entire structural complexity, are taken into account. Copyright © 2010 Elsevier Inc. All rights reserved.

  7. Cellulose nanomaterials in water treatment technologies.

    Science.gov (United States)

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

    2015-05-05

    Cellulose nanomaterials are naturally occurring with unique structural, mechanical and optical properties. While the paper and packaging, automotive, personal care, construction, and textiles industries have recognized cellulose nanomaterials' potential, we suggest cellulose nanomaterials have great untapped potential in water treatment technologies. In this review, we gather evidence of cellulose nanomaterials' beneficial role in environmental remediation and membranes for water filtration, including their high surface area-to-volume ratio, low environmental impact, high strength, functionalizability, and sustainability. We make direct comparison between cellulose nanomaterials and carbon nanotubes (CNTs) in terms of physical and chemical properties, production costs, use and disposal in order to show the potential of cellulose nanomaterials as a sustainable replacement for CNTs in water treatment technologies. Finally, we comment on the need for improved communication and collaboration across the myriad industries invested in cellulose nanomaterials production and development to achieve an efficient means to commercialization.

  8. Macroporous perovskite-type complex oxide catalysts of La_(1-x)K_xCo_(1-y)Fe_yO_3 for diesel soot combustion

    Institute of Scientific and Technical Information of China (English)

    张桂臻; 赵震; 刘坚; 徐俊峰; 荆延妮; 段爱军; 姜桂元

    2009-01-01

    A facile procedure was carried out to prepare macroporous perovskite-type complex oxide catalysts of La1-xKxCo1-yFeyO3(x=0,0.1,y=0,0.1) by using the combined method of organic ligation and solution combustion.This method could ensure the formation of the desired macroporous structures and the desired crystal phases of the prepared catalysts.It was found that the macroporous catalysts showed higher catalytic activities for soot combustion than that of the corresponding nanometric samples,and the macroporous ...

  9. One-Pot Route towards Active TiO2 Doped Hierarchically Porous Cellulose: Highly Efficient Photocatalysts for Methylene Blue Degradation

    Directory of Open Access Journals (Sweden)

    Xiaoxia Sun

    2017-03-01

    Full Text Available In this study, novel photocatalyst monolith materials were successfully fabricated by a non-solvent induced phase separation (NIPS technique. By adding a certain amount of ethyl acetate (as non-solvent into a cellulose/LiCl/N,N-dimethylacetamide (DMAc solution, and successively adding titanium dioxide (TiO2 nanoparticles (NPs, cellulose/TiO2 composite monoliths with hierarchically porous structures were easily formed. The obtained composite monoliths possessed mesopores, and two kinds of macropores. Scanning Electron Microscope (SEM, Energy Dispersive Spectroscopy (EDS, Fourier Transform Infrared Spectroscopy (FT-IR, X-ray Diffraction (XRD, Brunauer-Emmett-Teller (BET, and Ultraviolet-visible Spectroscopy (UV-Vis measurements were adopted to characterize the cellulose/TiO2 composite monolith. The cellulose/TiO2 composite monoliths showed high efficiency of photocatalytic activity in the decomposition of methylene blue dye, which was decomposed up to 99% within 60 min under UV light. Moreover, the composite monoliths could retain 90% of the photodegradation efficiency after 10 cycles. The novel NIPS technique has great potential for fabricating recyclable photocatalysts with highly efficiency.

  10. Ultrasound mediated enzymatic hydrolysis of cellulose and carboxymethyl cellulose.

    Science.gov (United States)

    Sulaiman, Ahmad Ziad; Ajit, Azilah; Chisti, Yusuf

    2013-01-01

    A recombinant Trichoderma reesei cellulase was used for the ultrasound-mediated hydrolysis of soluble carboxymethyl cellulose (CMC) and insoluble cellulose of various particle sizes. The hydrolysis was carried out at low intensity sonication (2.4-11.8 W cm(-2) sonication power at the tip of the sonotrode) using 10, 20, and 40% duty cycles. [A duty cycle of 10%, for example, was obtained by sonicating for 1 s followed by a rest period (no sonication) of 9 s.] The reaction pH and temperature were always 4.8 and 50°C, respectively. In all cases, sonication enhanced the rate of hydrolysis relative to nonsonicated controls. The hydrolysis of CMC was characterized by Michaelis-Menten kinetics. The Michaelis-Menten parameter of the maximum reaction rate Vmax was enhanced by sonication relative to controls, but the value of the saturation constant Km was reduced. The optimal sonication conditions were found to be a 10% duty cycle and a power intensity of 11.8 W cm(-2) . Under these conditions, the maximum rate of hydrolysis of soluble CMC was nearly double relative to control. In the hydrolysis of cellulose, an increasing particle size reduced the rate of hydrolysis. At any fixed particle size, sonication at a 10% duty cycle and 11.8 W cm(-2) power intensity improved the rate of hydrolysis relative to control. Under the above mentioned optimal sonication conditions, the enzyme lost about 20% of its initial activity in 20 min. Sonication was useful in accelerating the enzyme catalyzed saccharification of cellulose. © 2013 American Institute of Chemical Engineers.

  11. Controlled antiseptic release by alginate polymer films and beads.

    Science.gov (United States)

    Liakos, Ioannis; Rizzello, Loris; Bayer, Ilker S; Pompa, Pier Paolo; Cingolani, Roberto; Athanassiou, Athanassia

    2013-01-30

    Biodegradable polymeric materials based on blending aqueous dispersions of natural polymer sodium alginate (NaAlg) and povidone iodine (PVPI) complex, which allow controlled antiseptic release, are presented. The developed materials are either free standing NaAlg films or Ca(2+)-cross-linked alginate beads, which properly combined with PVPI demonstrate antibacterial and antifungal activity, suitable for therapeutic applications, such as wound dressing. Glycerol was used as the plasticizing agent. Film morphology was studied by optical and atomic force microscopy. It was found that PVPI complex forms well dispersed circular micro-domains within the NaAlg matrix. The beads were fabricated by drop-wise immersion of NaAlg/PVPI/glycerol solutions into aqueous calcium chloride solutions to form calcium alginate beads encapsulating PVPI solution (CaAlg/PVPI). Controlled release of PVPI was possible when the composite films and beads were brought into direct contact with water or with moist media. Bactericidal and fungicidal properties of the materials were tested against Escherichia coli bacteria and Candida albicans fungi. The results indicated very efficient antibacterial and antifungal activity within 48 h. Controlled release of PVPI into open wounds is highly desired in clinical applications to avoid toxic doses of iodine absorption by the wound. A wide variety of applications are envisioned such as external and internal wound dressings with controlled antiseptic release, hygienic and protective packaging films for medical devices, and polymer beads as water disinfectants.

  12. Fabrication of a microfluidic enzyme reactor utilizing magnetic beads.

    Science.gov (United States)

    Liu, Xiaojun; Lo, Roger C; Gomez, Frank A

    2009-06-01

    An enzyme-catalyzed microfluidic assay using magnetic micro-beads is described. Here, diaphorase (DI) (E.C. 1.6.99) is covalently attached to the magnetic micro-beads (2.7 mum) and integrated into a short section of a microchip fabricated from PDMS. DI converts non-fluorescent resazurin to fluorescent resorufin in the presence of nicotinamide adenine dinucleotide phosphate (NADH). In this work, an embedded magnet holds the micro-beads in place within the microchannel while a solution of resazurin and NADH in buffer is flowed through the beads. Incorporation of the micro-beads into the microchannel requires only a few minutes and offers well-defined spatial resolution and reproducibility. At a flow rate of 41.2 microL/h, a stable state for the enzyme reaction in the microfluidic format was achieved within 50 s. The maximum conversion of the reaction was obtained at a concentration of 1.25 mM NADH. The reaction yield is affected by ZnCl(2) and at concentrations in excess of 90.0 mM, the activity of DI was almost double without ZnCl(2). At 5.2 mM potassium chloride, the activity of DI reached its maximum value. Overall, the conversion of resazurin in microfluidic format was more than twice than that in a batch assay.

  13. Removal of uranium from aqueous solution by aliginate beads

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Jing; Wang, Jian Long [Collaborative Innovation Center for Advanced Nuclear Energy Technology, INET, Tsinghua University, Beijing (China); Jiang, Yizhou [Northwest Institute of Nuclear Technology, Xian (China)

    2017-04-15

    The adsorption of uranium (VI) by calcium alginate beads was examined by batch experiments. The effects of environmental conditions on U (VI) adsorption were studied, including contact time, pH, initial concentration of U (VI), and temperature. The alginate beads were characterized by using scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, and Fourier transform infrared spectroscopy. Fourier transform infrared spectra indicated that hydroxyl and alkoxy groups are present at the surface of the beads. The experimental results showed that the adsorption of U (VI) by alginate beads was strongly dependent on pH, the adsorption increased at pH 3∼7, then decreased at pH 7∼9. The adsorption reached equilibrium within 2 minutes. The adsorption kinetics of U (VI) onto alginate beads can be described by a pseudo first-order kinetic model. The adsorption isotherm can be described by the Redlich-Peterson model, and the maximum adsorption capacity was 237.15 mg/g. The sorption process is spontaneous and has an exothermic reaction.

  14. Fluorescent detection of C-reactive protein using polyamide beads

    Science.gov (United States)

    Jagadeesh, Shreesha; Chen, Lu; Aitchison, Stewart

    2016-03-01

    Bacterial infection causes Sepsis which is one of the leading cause of mortality in hospitals. This infection can be quantified from blood plasma using C - reactive protein (CRP). A quick diagnosis at the patient's location through Point-of- Care (POC) testing could give doctors the confidence to prescribe antibiotics. In this paper, the development and testing of a bead-based procedure for CRP quantification is described. The size of the beads enable them to be trapped in wells without the need for magnetic methods of immobilization. Large (1.5 mm diameter) Polyamide nylon beads were used as the substrate for capturing CRP from pure analyte samples. The beads captured CRP either directly through adsorption or indirectly by having specific capture antibodies on their surface. Both methods used fluorescent imaging techniques to quantify the protein. The amount of CRP needed to give a sufficient fluorescent signal through direct capture method was found suitable for identifying bacterial causes of infection. Similarly, viral infections could be quantified by the more sensitive indirect capture method. This bead-based assay can be potentially integrated as a disposable cartridge in a POC device due to its passive nature and the small quantities needed.

  15. Cellulose nanocrystal submonolayers by spin coating.

    Science.gov (United States)

    Kontturi, Eero; Johansson, Leena-Sisko; Kontturi, Katri S; Ahonen, Päivi; Thüne, Peter C; Laine, Janne

    2007-09-11

    Dilute concentrations of cellulose nanocrystal solutions were spin coated onto different substrates to investigate the effect of the substrate on the nanocrystal submonolayers. Three substrates were probed: silica, titania, and amorphous cellulose. According to atomic force microscopy (AFM) images, anionic cellulose nanocrystals formed small aggregates on the anionic silica substrate, whereas a uniform two-dimensional distribution of nanocrystals was achieved on the cationic titania substrate. The uniform distribution of cellulose nanocrystal submonolayers on titania is an important factor when dimensional analysis of the nanocrystals is desired. Furthermore, the amount of nanocrystals deposited on titania was multifold in comparison to the amounts on silica, as revealed by AFM image analysis and X-ray photoelectron spectroscopy. Amorphous cellulose, the third substrate, resulted in a somewhat homogeneous distribution of the nanocrystal submonolayers, but the amounts were as low as those on the silica substrate. These differences in the cellulose nanocrystal deposition were attributed to electrostatic effects: anionic cellulose nanocrystals are adsorbed on cationic titania in addition to the normal spin coating deposition. The anionic silica surface, on the other hand, causes aggregation of the weakly anionic cellulose nanocrystals which are forced on the repulsive substrate by spin coating. The electrostatically driven adsorption also influences the film thickness of continuous ultrathin films of cellulose nanocrystals. The thicker films of charged nanocrystals on a substrate of opposite charge means that the film thickness is not independent of the substrate when spin coating cellulose nanocrystals in the ultrathin regime (<100 nm).

  16. Polyimide Cellulose Nanocrystal Composite Aerogels

    Science.gov (United States)

    Nguyen, Baochau N.; Meador, Mary Ann; Rowan, Stuart; Cudjoe, Elvis; Sandberg, Anna

    2014-01-01

    Polyimide (PI) aerogels are highly porous solids having low density, high porosity and low thermal conductivity with good mechanical properties. They are ideal for various applications including use in antenna and insulation such as inflatable decelerators used in entry, decent and landing operations. Recently, attention has been focused on stimuli responsive materials such as cellulose nano crystals (CNCs). CNCs are environmentally friendly, bio-renewable, commonly found in plants and the dermis of sea tunicates, and potentially low cost. This study is to examine the effects of CNC on the polyimide aerogels. The CNC used in this project are extracted from mantle of a sea creature called tunicates. A series of polyimide cellulose nanocrystal composite aerogels has been fabricated having 0-13 wt of CNC. Results will be discussed.

  17. CELLULOSE DEGRADATION BY OXIDATIVE ENZYMES

    Directory of Open Access Journals (Sweden)

    Maria Dimarogona

    2012-09-01

    Full Text Available Enzymatic degradation of plant biomass has attracted intensive research interest for the production of economically viable biofuels. Here we present an overview of the recent findings on biocatalysts implicated in the oxidative cleavage of cellulose, including polysaccharide monooxygenases (PMOs or LPMOs which stands for lytic PMOs, cellobiose dehydrogenases (CDHs and members of carbohydrate-binding module family 33 (CBM33. PMOs, a novel class of enzymes previously termed GH61s, boost the efficiency of common cellulases resulting in increased hydrolysis yields while lowering the protein loading needed. They act on the crystalline part of cellulose by generating oxidized and non-oxidized chain ends. An external electron donor is required for boosting the activity of PMOs. We discuss recent findings concerning their mechanism of action and identify issues and questions to be addressed in the future.

  18. Cellulose degradation by oxidative enzymes

    Directory of Open Access Journals (Sweden)

    Maria Dimarogona

    2012-09-01

    Full Text Available Enzymatic degradation of plant biomass has attracted intensive research interest for the production of economically viable biofuels. Here we present an overview of the recent findings on biocatalysts implicated in the oxidative cleavage of cellulose, including polysaccharide monooxygenases (PMOs or LPMOs which stands for lytic PMOs, cellobiose dehydrogenases (CDHs and members of carbohydrate-binding module family 33 (CBM33. PMOs, a novel class of enzymes previously termed GH61s, boost the efficiency of common cellulases resulting in increased hydrolysis yields while lowering the protein loading needed. They act on the crystalline part of cellulose by generating oxidized and non-oxidized chain ends. An external electron donor is required for boosting the activity of PMOs. We discuss recent findings concerning their mechanism of action and identify issues and questions to be addressed in the future.

  19. Ex vivo mucoadhesion of different zinc-pectinate hydrogel beads.

    Science.gov (United States)

    Hagesaether, Ellen; Bye, Ragnar; Sande, S Arne

    2008-01-22

    The objective of this study was to investigate the mucoadhesive properties of pre-swelled hydrogel beads made of six types of pectin from three manufacturers. The types of pectin differed mainly in the degree of methoxylation and degree of amidation. Zinc ions were used as cross-linking agent. The mucoadhesive properties were tested on an inverted fresh porcine small intestine attached to a rotating cylinder. Beads made of pectin with a high degree of methoxylation (70%) showed superior mucoadhesive results compared to the other formulations, which could be correlated to the lower amount of zinc in this formulation, subsequently leading to a lower amount of cross-linking and higher mobility of the polymer chains of these beads. This study therefore also indicated the importance of doing mucoadhesive measurements on relevant formulations, and not basing the understanding solely on investigating polymer solutions. Samples from different manufacturers produced the same results.

  20. Damped bead on a rotating circular hoop - a bifurcation zoo

    CERN Document Server

    Dutta, Shovan

    2012-01-01

    The evergreen problem of a bead on a rotating hoop shows a multitude of bifurcations when the bead moves with friction. This motion is studied for different values of the damping coefficient and rotational speeds of the hoop. Phase portraits and trajectories corresponding to all different modes of motion of the bead are presented. They illustrate the rich dynamics associated with this simple system. For some range of values of the damping coefficient and rotational speeds of the hoop, linear stability analysis of the equilibrium points is inadequate to classify their nature. A technique involving transformation of coordinates and order of magnitude arguments is presented to examine such cases. This may provide a general framework to investigate other complex systems.

  1. Towards hybrid swimming microrobots: bacteria assisted propulsion of polystyrene beads.

    Science.gov (United States)

    Behkam, Bahareh; Sitti, Metin

    2006-01-01

    Compactness and efficiency of biomotors makes them superior to man-made actuators and a very attractive choice of actuation for micro/nanorobots. However, biomotors are difficult to work with due to complications associated with their isolation and reconstitution. To circumvent this problem, here we use flagellar motors inside the intact cell of S. marcescens bacteria. An array of bacteria is used as propeller for a 10 microm polystyrene (PS) bead. PS bead is tracked for several seconds and its displacements is compared with diffusion length of a 10 microm particle. It is shown that the bead moves with an average velocity of 17 microm/s. Orientation of adhesion of S. marcescens to polydimethylsiloxane (PDMS) chips and microscale PS fibers was also investigated. It is shown that for both substrates; only bacteria from farther behind the leading edge of the swarm adhere in end-on configuration.

  2. Effects of the hydraulic conductivity of the matrix/macropore interface on cumulative infiltrations into dual-permeability media

    Science.gov (United States)

    Lassabatere, L.; Peyrard, X.; Angulo-Jaramillo, R.; Simunek, J.

    2009-12-01

    Modeling of water infiltration into the vadose zone is important for better understanding of movement of water-transported contaminants. There is a great need to take into account the soil heterogeneity and, in particular, the presence of macropores or cracks that could generate preferential flow. Several mathematical models have been proposed to describe unsaturated flow through heterogeneous soils. The dual-permeability model (referred to as the 2K model) assumes that flow is governed by Richards equation in both porous regions (matrix and macropores). Water can be exchanged between the two regions following a first-order rate law. Although several studies have dealt with such modeling, no study has evaluated the influence of the hydraulic conductivity of the matrix/macropore interface on water cumulative infiltration. And this is the focus of this study. An analytical scaling method reveals the role of the following main parameters for given boundary and initial conditions: the saturated hydraulic conductivity ratio (R_Ks), the water pressure scale parameter ratio (R_hg), the saturated volumetric water content ratio (R_θs), and the shape parameters of the water retention and hydraulic conductivity functions. The last essential parameter is related to the interfacial hydraulic conductivity (Ka) between the macropore and matrix regions. The scaled 2K flow equations were solved using HYDRUS-1D 4.09 for the specific case of water infiltrating into an initially uniform soil profile and a zero pressure head at the soil surface. A sensitivity of water infiltration was studied for different sets of scale parameters (R_Ks, R_hg, R_θs, and shape parameters) and the scaled interfacial conductivity (Ka). Numerical results illustrate two extreme behaviors. When the interfacial conductivity is zero (i.e., no water exchange), water infiltrates separately into matrix and macropore regions, producing a much deeper moisture front in the macropore domain. In the opposite case

  3. Preparation of 14C Radiolabelled Sodium Carboxymethyl Cellulose

    Institute of Scientific and Technical Information of China (English)

    CHEN; Bao-jun; YANG; Hong-wei; LI; Shuai

    2013-01-01

    Carboxymethyl cellulose(CMC)is a kind of cellulose derivative.CMC has wide applications,including food,daily chemicals,pharmaceutical industry and chemical industry,etc.In order to study the metabolism of CMC,the sodium carboxymethyl cellulose was labelled with 14C.The carboxymethyl cellulose was labelled with 14C by treatment with alkalized cellulose and 14C-

  4. Flexible Photonic Cellulose Nanocrystal Films

    OpenAIRE

    Guidetti, G.; Atifi, S; Vignolini, S; Hamad, WY

    2016-01-01

    The fabrication of self-assembled cellulose nanocrystal (CNC) films of tunable photonic and mechanical properties using a facile, green approach is demonstrated. The combination of tunable flexibility and iridescence can dramatically expand CNC coating and film barrier capabilities for paints and coating applications, sustainable consumer packaging products, as well as effective templates for photonic and optoelectronic materials and structures. CelluForce Inc., Biotechnology and Biologica...

  5. Quantification of 3D macropore networks in forest soils in Touzhai valley (Yunnan, China) using X-ray computed tomography and image analysis

    Institute of Scientific and Technical Information of China (English)

    ZHANG Jia-ming; XU Ze-min; LI Feng; HOU Ru-ji; REN Zhe

    2017-01-01

    The three dimensional (3D) geometry of soil macropores largely controls preferential flow,which is a significant infiltrating mechanism for rainfall in forest soils and affects slope stability.However,detailed studies on the 3D geometry of macropore networks in forest soils are rare.The intense rainfall-triggered potentially unstable slopes were threatening the villages at the downstream of Touzhai valley (Yunnan,China).We visualized and quantified the 3D macropore networks in undisturbed soil columns (Histosols) taken from a forest hillslope in Touzhai valley,and compared them with those in agricultural soils (corn and soybean in USA;barley,fodder beet and red fescue in Denmark) and grassland soils in USA.We took two large undisturbed soil columns (250 mmx250 mm×500 mm),and scanned the soil columns at in-situ soil water content conditions using X-ray computed tomography at a voxel resolution of 0.945 x 0.945 × 1.500 mm3.After reconstruction and visualization,we quantified the characteristics of macropore networks.In the studied forest soils,the main types of macropores were root channels,inter-aggregate voids,macropores without knowing origin,root-soil interface and stone-soil interface.While macropore networks tend to be more complex,larger,deeper and longer.The forest soils have high macroporosity,total macropore wall area density,node density,and large macropore volume,hydraulic radius,mean macropore length,angle,and low tortuosity.The findings suggest that macropore networks in the forest soils have high interconnectivity,vertical continuity,linearity and less vertically oriented.

  6. TRANSPLANTATION OF CRYOPRESERVED FETAL LIVER CELLS SEEDED INTO MACROPOROUS ALGINATE-GELATIN SCAFFOLDS IN RATS WITH LIVER FAILURE

    Directory of Open Access Journals (Sweden)

    D. V. Grizay

    2015-01-01

    Full Text Available Aim. To study the therapeutic potential of cryopreserved fetal liver cells seeded into macroporous alginategelatin scaffolds after implantation to omentum of rats with hepatic failure.Materials and methods.Hepatic failure was simulated by administration of 2-acetyl aminofl uorene followed partial hepatectomy. Macroporous alginate-gelatin scaffolds, seeded with allogenic cryopreserved fetal liver cells (FLCs were implanted into rat omentum. To prevent from colonization of host cells scaffolds were coated with alginate gel shell. Serum transaminase activity, levels of albumin and bilirubin as markers of hepatic function were determined during 4 weeks after failure model formation and scaffold implantation. Morphology of liver and scaffolds after implantation were examined histologically. Results. Macroporous alginate-gelatin scaffolds after implantation to healthy rats were colonized by host cells. Additional formation of alginate gel shell around scaffolds prevented the colonization. Implantation of macroporous scaffolds seeded with cryopreserved rat FLCs and additionally coated with alginate gel shell into omentum of rats with hepatic failure resulted in signifi cant improvement of hepatospecifi c parameters of the blood serum and positive changes of liver morphology. The presence of cells with their extracellular matrix within the scaffolds was confi rmed after 4 weeks post implantation.Conclusion. The data above indicate that macroporous alginate-gelatin scaffolds coated with alginate gel shell are promising cell carriers for the development of bioengineered liver equivalents.

  7. A simple method for the production of large volume 3D macroporous hydrogels for advanced biotechnological, medical and environmental applications

    Science.gov (United States)

    Savina, Irina N.; Ingavle, Ganesh C.; Cundy, Andrew B.; Mikhalovsky, Sergey V.

    2016-02-01

    The development of bulk, three-dimensional (3D), macroporous polymers with high permeability, large surface area and large volume is highly desirable for a range of applications in the biomedical, biotechnological and environmental areas. The experimental techniques currently used are limited to the production of small size and volume cryogel material. In this work we propose a novel, versatile, simple and reproducible method for the synthesis of large volume porous polymer hydrogels by cryogelation. By controlling the freezing process of the reagent/polymer solution, large-scale 3D macroporous gels with wide interconnected pores (up to 200 μm in diameter) and large accessible surface area have been synthesized. For the first time, macroporous gels (of up to 400 ml bulk volume) with controlled porous structure were manufactured, with potential for scale up to much larger gel dimensions. This method can be used for production of novel 3D multi-component macroporous composite materials with a uniform distribution of embedded particles. The proposed method provides better control of freezing conditions and thus overcomes existing drawbacks limiting production of large gel-based devices and matrices. The proposed method could serve as a new design concept for functional 3D macroporous gels and composites preparation for biomedical, biotechnological and environmental applications.

  8. Nanocomposite synthesis by absorption of nanoparticles into macroporous hydrogels. Building a chemomechanical actuator driven by electromagnetic radiation.

    Science.gov (United States)

    Molina, M A; Rivarola, C R; Miras, M C; Lescano, D; Barbero, C A

    2011-06-17

    Macroporous hydrogels irreversibly absorb solid nanoparticles from aqueous dispersions. A nanocomposite is made using a macroporous thermosensitive hydrogel (poly(N-isopropylacrylamide-co-(2-acrylamido-2-methyl propane sulfonic acid)) (poly(NIPAm-co-AMPS)) and conductive polymer (polyaniline, PANI) nanoparticles (PANI NPs). Macroporous gels of poly(NIPAm-co-AMPS) were made by a cryogelation technique. NPs of PANI were produced by precipitation polymerization. It is found that PANI NPs are easily absorbed into the macroporous hydrogels while conventional non-porous hydrogels do not incorporate NPs. It is shown that PANI NPs, dispersed in water, absorb NIR laser light or microwave radiation, increasing their temperature. Upon irradiation of the nanocomposite with microwaves or NIR laser light, the PANI NPs heat up and induce the phase transition of the thermosensitive hydrogel matrix and the internal solution is released. Other nano-objects, such as gold nanorods and PANI nanofibers, are also easily incorporated into the macroporous gel. The resulting nanocomposites also suffer a phase transition upon irradiation with electromagnetic waves. The results suggest that, using a thermosensitive matrix and conducting nanoparticles, mechanical/chemical actuators driven at a distance by electromagnetic radiation can be built. The sensitivity of the nanocomposite to electromagnetic radiation can be modulated by the pH, depending on the nature of the incorporated nanoparticles. Additionally, it is possible to make systems which absorb either NIR or microwaves or both.

  9. Nanocomposite synthesis by absorption of nanoparticles into macroporous hydrogels. Building a chemomechanical actuator driven by electromagnetic radiation

    Energy Technology Data Exchange (ETDEWEB)

    Molina, M A; Rivarola, C R; Miras, M C; Lescano, D; Barbero, C A, E-mail: cbarbero@exa.unrc.edu.ar [Programa de Materiales Avanzados, Departamento de Quimica, Universidad Nacional de Rio Cuarto, Ruta 8, km 601, Agencia postal No 3, 5800 Rio Cuarto (Argentina)

    2011-06-17

    Macroporous hydrogels irreversibly absorb solid nanoparticles from aqueous dispersions. A nanocomposite is made using a macroporous thermosensitive hydrogel (poly(N-isopropylacrylamide-co-(2-acrylamido-2-methyl propane sulfonic acid)) (poly(NIPAm-co-AMPS)) and conductive polymer (polyaniline, PANI) nanoparticles (PANI NPs). Macroporous gels of poly(NIPAm-co-AMPS) were made by a cryogelation technique. NPs of PANI were produced by precipitation polymerization. It is found that PANI NPs are easily absorbed into the macroporous hydrogels while conventional non-porous hydrogels do not incorporate NPs. It is shown that PANI NPs, dispersed in water, absorb NIR laser light or microwave radiation, increasing their temperature. Upon irradiation of the nanocomposite with microwaves or NIR laser light, the PANI NPs heat up and induce the phase transition of the thermosensitive hydrogel matrix and the internal solution is released. Other nano-objects, such as gold nanorods and PANI nanofibers, are also easily incorporated into the macroporous gel. The resulting nanocomposites also suffer a phase transition upon irradiation with electromagnetic waves. The results suggest that, using a thermosensitive matrix and conducting nanoparticles, mechanical/chemical actuators driven at a distance by electromagnetic radiation can be built. The sensitivity of the nanocomposite to electromagnetic radiation can be modulated by the pH, depending on the nature of the incorporated nanoparticles. Additionally, it is possible to make systems which absorb either NIR or microwaves or both.

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

    Science.gov (United States)

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

    2016-01-20

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

  11. Half-bead weld repairs for in-service applications

    Energy Technology Data Exchange (ETDEWEB)

    Holz, P.P. Sr.

    1978-01-01

    Successful half- or temper-bead technique weld repairs performed to Section XI of the American Society of Mechanical Engineers Boiler and Pressure Vessel Code guidelines were made to two Heavy-Section Steel Technology Program vessels and a qualification prolongation. Intermediate sized vessels, equivalent in thickness to nuclear pressure vessels, were repair welded and subsequently flawed and pressure tested to approximately 2/sup 1///sub 4/ times design pressure before leakage occurred. Discussed are the standards and procedures used with half-bead repairs, resultant induced metallurgical and stress effects, flaw test criterion, pressure test details and results, and recommendations for further development work for a speedier application process.

  12. Magnetic manipulation and sensing of beads for bioapplications

    DEFF Research Database (Denmark)

    Henriksen, Anders Dahl

    magnetic stack. The permalloy micro stripes created a spatially varying magnetic field, which in combination with a rotating external field was used to transport magnetic beads from stripe to stripe. Systematic measurements of the magnetophoresis properties on varying stripe geometries were performed....... This method was also tried for studying of aptamer hybridization to magnetic beads coated with virus protein, a so-called magnetic artificial virus. Two aptamers from the literature were tried, but none of them showed any significant hybridization to the artificial virus. Last Part IV performed a thorough...

  13. 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.

  14. Assessment of solvents for cellulose dissolution.

    Science.gov (United States)

    Ghasemi, Mohammad; Tsianou, Marina; Alexandridis, Paschalis

    2017-03-01

    A necessary step in the processing of biomass is the pretreatment and dissolution of cellulose. A good solvent for cellulose involves high diffusivity, aggressiveness in decrystallization, and capability of disassociating the cellulose chains. However, it is not clear which of these factors and under what conditions should be improved in order to obtain a more effective solvent. To this end, a newly-developed phenomenological model has been applied to assess the controlling mechanism of cellulose dissolution. Among the findings, the cellulose fibers remain crystalline almost to the end of the dissolution process for decrystallization-controlled kinetics. In such solvents, decreasing the fiber crystallinity, e.g., via pretreatment, would result in a considerable increase in the dissolution rate. Such insights improve the understanding of cellulose dissolution and facilitate the selection of more efficient solvents and processing conditions for biomass. Specific examples of solvents are provided where dissolution is limited due to decrystallization or disentanglement.

  15. Alexa Fluor-labeled Fluorescent Cellulose Nanocrystals for Bioimaging Solid Cellulose in Spatially Structured Microenvironments

    Energy Technology Data Exchange (ETDEWEB)

    Grate, Jay W.; Mo, Kai-For; Shin, Yongsoon; Vasdekis, Andreas; Warner, Marvin G.; Kelly, Ryan T.; Orr, Galya; Hu, Dehong; Dehoff, Karl J.; Brockman, Fred J.; Wilkins, Michael J.

    2015-03-18

    Cellulose nanocrystal materials have been labeled with modern Alexa Fluor dyes in a process that first links the dye to a cyanuric chloride molecule. Subsequent reaction with cellulose nanocrystals provides dyed solid microcrystalline cellulose material that can be used for bioimaging and suitable for deposition in films and spatially structured microenvironments. It is demonstrated with single molecular fluorescence microscopy that these films are subject to hydrolysis by cellulose enzymes.

  16. Alteration of in vivo cellulose ribbon assembly by carboxymethylcellulose and other cellulose derivatives

    OpenAIRE

    1982-01-01

    In vivo cellulose ribbon assembly by the Gram-negative bacterium Acetobacter xylinum can be altered by incubation in carboxymethylcellulose (CMC), a negatively charged water-soluble cellulose derivative, and also by incubation in a variety of neutral, water-soluble cellulose derivatives. In the presence of all of these substituted celluloses, normal fasciation of microfibril bundles to form the typical twisting ribbon is prevented. Alteration of ribbon assembly is most extensive in the presen...

  17. Drag Reduction of Bacterial Cellulose Suspensions

    Directory of Open Access Journals (Sweden)

    Satoshi Ogata

    2011-01-01

    Full Text Available Drag reduction due to bacterial cellulose suspensions with small environmental loading was investigated. Experiments were carried out by measuring the pressure drop in pipe flow. It was found that bacterial cellulose suspensions give rise to drag reduction in the turbulent flow range. We observed a maximum drag reduction ratio of 11% and found that it increased with the concentration of the bacterial cellulose suspension. However, the drag reduction effect decreased in the presence of mechanical shear.

  18. Size Effects of Nano-crystalline Cellulose

    Institute of Scientific and Technical Information of China (English)

    Guo Kang LI; Xiao Fang LI; Yong JIANG; Mei Zhen ZENG; En Yong DING

    2003-01-01

    Natural cellulose with the crystal form of cellulose Ⅰ, when treated with condensed lye(e.g. 18%NaOH), can change into new crystal form of cellulose Ⅱ. But the nano-crystallinecellulose(NCC) can do it when only treated with dilute lye (e.g. 1%NaOH) at room temperatureand even can dissolve into slightly concentrated lye (e.g. 4%NaOH).

  19. Cellulose nanomaterials review: structure, properties and nanocomposites

    OpenAIRE

    Moon, Robert J.; Martini, Ashlie; Nairn, John; Simonsen, John; Youngblood, Jeffrey

    2011-01-01

    This critical review provides a processing-structure-property perspective on recent advances in cellulose nanoparticles and composites produced from them. It summarizes cellulose nanoparticles in terms of particle morphology, crystal structure, and properties. Also described are the self-assembly and rheological properties of cellulose nanoparticle suspensions. The methodology of composite processing and resulting properties are fully covered, with an emphasis on neat and high fraction...

  20. Chemo-catalytic valorization of cellulose

    Energy Technology Data Exchange (ETDEWEB)

    Palkovits, R. [RWTH Aachen Univ. (Germany). Inst. fuer Technische und Makromolekulare Chemie

    2012-07-01

    Cellulose can be utilized as carbon source for the production of novel platform molecules as well as fuel motifs. Promising transformation strategies cover the hydrolytic hydrogenation or hydrogenolysis of cellulose to sugar alcohols, the hydrolysis of cellulose to glucose followed by dehydration to 5-hydroxymethylfurfural or levulinic acid and the further hydrogenation of levulinic acid to {gamma}-valerolactone. Main challenges result from the high degree of functionalization of cellulosic feedstocks. In line, processes are carried out in liquid phase utilizing rather polar solvents and aiming for a tailored defunctionalisation of these oxygen rich compounds. Consequently, such transformations require novel strategies concerning the development of suitable catalysts and appropriate process concepts. (orig.)

  1. Chemo-catalytic valorization of cellulose

    Energy Technology Data Exchange (ETDEWEB)

    Palkovits, R. [RWTH Aachen Univ. (Germany). Inst. fuer Technische und Makromolekulare Chemie

    2012-07-01

    Cellulose can be utilized as carbon source for the production of novel platform molecules as well as fuel motifs. Promising transformation strategies cover the hydrolytic hydrogenation or hydrogenolysis of cellulose to sugar alcohols, the hydrolysis of cellulose to glucose followed by dehydration to 5-hydroxymethylfurfural or levulinic acid and the further hydrogenation of levulinic acid to {gamma}-valerolactone. Main challenges result from the high degree of functionalization of cellulosic feedstocks. In line, processes are carried out in liquid phase utilizing rather polar solvents and aiming for a tailored defunctionalisation of these oxygen rich compounds. Consequently, such transformations require novel strategies concerning the development of suitable catalysts and appropriate process concepts. (orig.)

  2. Cytocompatible cellulose hydrogels containing trace lignin.

    Science.gov (United States)

    Nakasone, Kazuki; Kobayashi, Takaomi

    2016-07-01

    Sugarcane bagasse was used as a cellulose resource to prepare transparent and flexible cellulose hydrogel films. On the purification process from bagasse to cellulose, the effect of lignin residues in the cellulose was examined for the properties and cytocompatibility of the resultant hydrogel films. The cellulose was dissolved in lithium chloride/N,N-dimethylacetamide solution and converted to hydrogel films by phase inversion. In the purification process, sodium hydroxide (NaOH) treatment time was changed from 1 to 12h. This resulted in cellulose hydrogel films having small amounts of lignin from 1.62 to 0.68%. The remaining lignin greatly affected hydrogel properties. Water content of the hydrogel films was increased from 1153 to 1525% with a decrease of lignin content. Moreover, lower lignin content caused weakening of tensile strength from 0.80 to 0.43N/mm(2) and elongation from 45.2 to 26.5%. Also, similar tendency was observed in viscoelastic behavior of the cellulose hydrogel films. Evidence was shown that the lignin residue was effective for the high strength of the hydrogel films. In addition, scanning probe microscopy in the morphological observation was suggested that the trace lignin in the cellulose hydrogel affected the cellulose fiber aggregation in the hydrogel network. The trace of lignin in the hydrogels also influenced fibroblast cell culture on the hydrogel films. The hydrogel film containing 1.68% lignin showed better fibroblast compatibility as compared to cell culture polystyrene dish used as reference.

  3. Carboxymethylation of Cellulose by Microwave irradiation

    Institute of Scientific and Technical Information of China (English)

    YE Jun; XIONG Jian; SU Yingzhi; XIAO Ping

    2001-01-01

    @@ Cellulose may be readily converted into ethers involving primary and secondary alcohol groups in each monomer unit and the glycosidic bonds. However, these reactions are rather more complicated than with simple substances, because the stereochemistry of the cellulose molecule is such that the vast majority of its hydroxyl groups form intra-chain hydrogen bonds or inter-chain hydrogen bonds with contiguous molecules. Carboxymethylcellulose (CMC) has played an important part in the commercial uses of cellulose derivatives. CMC becomes alkali and water soluble. The polarity can, in fact, be increased by introduction of ionizing groups, ie carboxymethyl group. CMC is generally produced by the reaction of alkali cellulose with chloroacetic acid.

  4. [Supramolecular reorganizations in cellulose during hydration].

    Science.gov (United States)

    Grunin, Iu B; Grunin, L Iu; Talantsev, V I; Nikol'skaia, E A; Masas, D S

    2015-01-01

    The analysis of modern ideas about the structural organization of the cellulose microfibrils is carried out. The mechanism of the formation of additional capillary-porous system of cellulose under moistening is offered. It is established that when the moisture content of cellulose reaches 8-10%, the filling of its micropores occurs with a simultaneous increase in their cross sizes, a specific surface and reduction in the degree of crystallinity of specimens. Within the proposed model of microfibril construction the parameters of supramolecular structure and capillary-porous system of cotton cellulose are determined.

  5. Simultaneous cellulose conversion and hydrogen production assisted by cellulose decomposition under UV-light photocatalysis.

    Science.gov (United States)

    Zhang, Guan; Ni, Chengsheng; Huang, Xiubing; Welgamage, Aakash; Lawton, Linda A; Robertson, Peter K J; Irvine, John T S

    2016-01-28

    Photocatalytic conversion of cellulose to sugars and carbon dioxide with simultaneous production of hydrogen assisted by cellulose decomposition under UV or solar light irradiation was achieved upon immobilization of cellulose onto a TiO2 photocatalyst. This approach enables production of hydrogen from water without using valuable sacrificial agents, and provides the possibility for recovering sugars as liquid fuels.

  6. Liquid crystalline solutions of cellulose in phosphoric acid for preparing cellulose yarns

    NARCIS (Netherlands)

    Boerstoel, H.

    2006-01-01

    The presen thesis describes a new process for manufacturing high tenacity and high modulus cellulose yarns. A new direct solvent for cellulose has been discovered, leading to liquid crystalline solutions. This new solvent, superphosphoric acid, rapidly dissolves cellulose. These liquid crystalline s

  7. Preparation of Chitosan Nanocompositeswith a Macroporous Structure by Unidirectional Freezing and Subsequent Freeze-Drying

    Directory of Open Access Journals (Sweden)

    Inmaculada Aranaz

    2014-11-01

    Full Text Available Chitosan is the N-deacetylated derivative of chitin, a naturally abundant mucopolysaccharide that consists of 2-acetamido-2-deoxy-β-d-glucose through a β (1→4 linkage and is found in nature as the supporting material of crustaceans, insects, etc. Chitosan has been strongly recommended as a suitable functional material because of its excellent biocompatibility, biodegradability, non-toxicity, and adsorption properties. Boosting all these excellent properties to obtain unprecedented performances requires the core competences of materials chemists to design and develop novel processing strategies that ultimately allow tailoring the structure and/or the composition of the resulting chitosan-based materials. For instance, the preparation of macroporous materials is challenging in catalysis, biocatalysis and biomedicine, because the resulting materials will offer a desirable combination of high internal reactive surface area and straightforward molecular transport through broad “highways” leading to such a surface. Moreover, chitosan-based composites made of two or more distinct components will produce structural or functional properties not present in materials composed of one single component. Our group has been working lately on cryogenic processes based on the unidirectional freezing of water slurries and/or hydrogels, the subsequent freeze-drying of which produce macroporous materials with a well-patterned structure. We have applied this process to different gels and colloidal suspensions of inorganic, organic, and hybrid materials. In this review, we will describe the application of the process to chitosan solutions and gels typically containing a second component (e.g., metal and ceramic nanoparticles, or carbon nanotubes for the formation of chitosan nanocomposites with a macroporous structure. We will also discuss the role played by this tailored composition and structure in the ultimate performance of these materials.

  8. Impedance measurement for microstructure characterization and internal surface estimation of macroporous silicon

    Energy Technology Data Exchange (ETDEWEB)

    RoyChaudhuri, C. [Department of Electronics and Telecommunication Engineering, Bengal Engineering and Science University, Shibpur, Botanic Garden, Howrah 711103 (India); Jana, M.; Bandopadhyay, N.R. [School of Materials Science and Engineering, Bengal Engineering and Science University, Shibpur, Botanic Garden, Howrah 711103 (India)

    2010-09-15

    In this paper, a simple and convenient method based on impedance measurement has been proposed for the first time to evaluate the average porosity, pore radius, and internal surface area of macroporous silicon structure fabricated by electrochemical method. The porosity and the average pore radius have been obtained by developing a geometrical model and applying the generalized effective medium approximation theory to the dc and ac impedance measurement of both unoxidized and thermally oxidized macroporous silicon. The internal surface area per unit volume is then computed from the porosity and the pore radius using the same model. The method has been applied to a wide range of porosity from 30 to 58% fabricated on p-type <100> silicon with a resistivity of 10-20 {omega} cm. Experimental verification of porosity, mean pore radius, and internal surface area have been performed by standard gravimetric technique and by top-view and cross-section SEM imaging, respectively. A typical mean pore radius, porosity, and internal surface area of a macroporous silicon sample has been obtained to be 1.52 {mu}m, 54.2%, and 3565.7 cm{sup 2}/cm{sup 3}, respectively, from the impedance measurement and 1.5 {mu}m, 55%, and 3666.7 cm{sup 2}/cm{sup 3} from SEM and gravimetric analysis which shows that the results are within 2% of the values obtained by conventional methods. The advantages of this method over the other recently reported techniques for similar characterization have been discussed. (Abstract Copyright [2010], Wiley Periodicals, Inc.)

  9. PREPARATION OF MACROPOROUS TIO2 BY STARCH MICROSPHERES TEMPLATE WITH ASSISTANCE OF SUPERCRITICAL CO2

    Directory of Open Access Journals (Sweden)

    Lin-Qi Tang

    2009-02-01

    Full Text Available In this work a green route is reported to prepare a TiO2 macroporous network using corn starch microspheres flake as a bio-template. The starch microspheres prepared by emulsion technology were used as a template into which precursor tetrabutyl titanate (TBOT was permeated using supercritical carbon dioxide (scCO2 as a forceful carrier or infiltration media, resulting in the formation of an organic/inorganic hybrid material; then the coated template was gelled and dried during the scCO2-coating and the depressurization processes, followed by removal of the template by calcination at 700°C; finally, TiO2 inverse-opals-like material reversely replicating the starch microspheres template was obtained. Scanning electron microscopy (SEM, nitrogen sorption measurements, and X-ray diffraction (XRD indicated that the products were the inverse replicas from their templates. The obtained TiO2 inverse opals-like material showed a wide dispersion of pore sizes from mesopores to macropores – a few nanometers to several micrometers –with the BET surface area up to 103 m2/g, and a predominantly anatase crystalline phase. In addition, the wall thickness of the macropores varied with tunable pressure for closed cells or open-cell foams. So this facile and environmentally friendly process for the preparation of high-surface area, thermally-stable, metal-oxide catalysts and supports by a starch microsphere templating approach may have widespread potential applications in catalysis, absorbents, photoelectric materials, and so on.

  10. Development of macroporous calcium phosphate scaffold processed via microwave rapid drying

    Energy Technology Data Exchange (ETDEWEB)

    Jamuna-Thevi, K., E-mail: jamuna@sirim.my [Advanced Materials Research Centre (AMREC), SIRIM Berhad, Lot 34, Jalan Hi-Tech 2/3, Kulim Hi-Tech Park, 09000 Kulim, Kedah (Malaysia); Zakaria, F.A. [Advanced Materials Research Centre (AMREC), SIRIM Berhad, Lot 34, Jalan Hi-Tech 2/3, Kulim Hi-Tech Park, 09000 Kulim, Kedah (Malaysia); Othman, R. [Materials and Mineral Resources Engineering, Engineering Campus, Universiti Sains Malaysia, Seri Ampangan, 14300 Nibong Tebal, Penang (Malaysia); Muhamad, S. [Bioassay Unit, Herbal Medicine Research Centre (HMRC), Institute for Medical Research (IMR), Jalan Pahang, 50588 Kuala Lumpur (Malaysia)

    2009-06-01

    Porous hydroxyapatite (HA) scaffold has great potential in bone tissue engineering applications. A new method to fabricate macroporous calcium phosphate (CP) scaffold via microwave irradiation, followed by conventional sintering to form HA scaffold was developed. Incorporation of trisodium citrate dihydrate and citric acid in the CP mixture gave macroporous scaffolds upon microwave rapid drying. In this work, a mixture of {beta}-tricalcium phosphate ({beta}-TCP), calcium carbonate (CaCO{sub 3}), trisodium citrate dihydrate, citric acid and double distilled de-ionised water (DDI) was exposed to microwave radiation to form a macroporous structure. Based on gross eye examinations, addition of trisodium citrate at 30 and 40 wt.% in the CP mixture ({beta}-TCP and CaCO{sub 3}) without citric acid indicates increasing order of pore volume where the highest porosity yield was observed at 40 wt.% of trisodium citrate addition and the pore size was detected at several millimeters. Therefore, optimization of pore size was performed by adding 3-7 wt.% of citric acid in the CP mixture which was separately mixed with 30 and 40 wt.% of trisodium citrate for comparison purposes. Fabricated scaffolds were calcined at 600 deg. C and washed with DDI water to remove the sodium hydroxycarbonate and sintered at 1250 deg. C to form HA phase as confirmed in the X-ray diffraction (XRD) results. Based on Archimedes method, HA scaffolds prepared from 40 wt.% of trisodium citrate with 3-7 wt.% of citric acid added CP mixture have an open and interconnected porous structure ranging from 51 to 53 vol.% and observation using Scanning electron microscope (SEM) showed the pore size distribution between 100 and 500 {mu}m. The cytotoxicity tests revealed that the porous HA scaffolds have no cytotoxic potential on MG63 osteoblast-like cells which might allow for their use as biomaterials.

  11. Effect of deposit composition on the mechanical properties and cracking tendency of cellulosic-covered SMAW weld deposits

    Energy Technology Data Exchange (ETDEWEB)

    James, Matthew J.; Weaver, Robert J.; Quintana, Marie A.; Savrin, Tamara [The Lincoln Electric Company, Cleveland, Ohio, (United States)

    2010-07-01

    Boron is a concern in the pipeline industry, where its propensity to cause cracking is a concern. The goal of this study is to quantify the effect of changes in deposit composition - specifically boron and Pcm on the properties of cellulosic weld deposits. Four trial electrodes with different concentrations of boron were tested. One, in which the boron was replaced by the same amount of carbon, is the reference test specimen without boron. Gapped bead on plate testing was used to determine the propensity of the electrodes for weld metal cracking. The results do not provide a clear picture of the influence of boron. Replacing boron with carbon showed very slight differences. In most trials, the effect of boron was not found to be significant. In the case of hydrogen assisted cold cracking (HACC), other factors should be investigated but removing the boron is not enough to reduce the sensitivity of cellulosic weld metal to cracking.

  12. 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

  13. Macroporous silicon membranes as electron and x-ray transmissive windows

    OpenAIRE

    Schilling, J.; Scherer, A; Gösele, U; Kolbe, M.

    2004-01-01

    Macroporous silicon membranes are fabricated whose pores are terminated with 60 nm thin silicon dioxide shells. The transmission of electrons with energies of 5 kV-25 kV through these membranes was investigated reaching a maximum of 22% for 25 kV. Furthermore, the transmission of electromagnetic radiation ranging from the far-infrared to the x-ray region was determined. The results suggest the application of the membrane as window material for electron optics and energy dispersive x-ray detec...

  14. Synthesis of 3-D ordered macroporous silicate using the template formed from monodispersed polystyrene latex

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Based on the template formed from monodispersed polystyrene (PS) latex, a modified fast sol-gel process was employed to synthesize a three-dimensional ( 3-D ) ordered macroporous silica material after removing the template by calcination at high temperature. It was indicated that there existed highly ordered packed pores within the whole silica material by SEM morphology observation. It was also found that the pores were interconnected. The pore size could be controlled mainly by varying the particle size of the latex ranging from 101 to 102 nm. The formation process of the ordered pores was also preliminarily discussed.

  15. Electrochemical synthesis of macroporous zinc oxide layers by employing hydrogen peroxide as oxygen precursor

    Energy Technology Data Exchange (ETDEWEB)

    Ramirez, Daniel [Laboratoire d' Electrochimie et Chimie Analytique (UMR CNRS 7575), Ecole Nationale Superieure de Chimie de Paris (ENSCP) (France); Instituto de Quimica, Pontificia Universidad Catolica de Valparaiso, Valparaiso (Chile); Bartlett, Philip; Abdelsalam, Mamdouh [School of Chemistry, University of Southampton (United Kingdom); Gomez, Humberto [Instituto de Quimica, Pontificia Universidad Catolica de Valparaiso, Valparaiso (Chile); Lincot, Daniel [Laboratoire d' Electrochimie et Chimie Analytique (UMR CNRS 7575), Ecole Nationale Superieure de Chimie de Paris (ENSCP) (France)

    2008-10-15

    Two- and three-dimensional ordered porous zinc oxide (ZnO) films were prepared by electrodeposition on Indium Tin Oxide coated glass, using two- and three-dimensional poly(styrene) opal templates. The oxide was formed by electrochemical reduction of hydrogen peroxide in aqueous zinc perchlorate solution. Scanning electron microscopy measurements showed well ordered inverse opal structures for macroporous ZnO. At high hydrogen peroxide concentration, dense inner conformal filling was achieved for 2D and 3D structures. The formation of nanocrystalline ZnO was checked by X-ray diffraction. (copyright 2008 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  16. SYNTHESIS OF SPHERICAL MACROPOROUS ADSORBENT BASED ON UREA—FORMALDEHYDE CONDENSED POLYMER

    Institute of Scientific and Technical Information of China (English)

    XUMingcheng; XUMancai; 等

    2000-01-01

    Spherical macroporous adsorbents with active sites capable of hydrogen bonding adsorption based on urea-formaldehyde condensed polymer were synthesized via reversed suspension polymerization.The properties of the obtained adsorbent were also investigated in detail.The results showed that the water permeability could be improved by adding hydroxyl-contatining organic compound moiety into the adsorbent.The specific surface area and average pore diameter of these adsorbents increaswed while the porosity first increased then decreased with the increase of the amount of the added hydroxyl-containing compound.

  17. Macroporous hydrogels based on 2-hydroxyethyl methacrylate. Part III. Hydrogels as carriers for immobilization of proteins.

    Science.gov (United States)

    Michálek, J; Prádný, M; Artyukhov, A; Slouf, M; Smetana, K

    2005-08-01

    Four series of macroporous hydrogels based on crosslinked copolymers of 2-hydroxyethyl methacrylate (HEMA)-sodium methacrylate (MANa), copolymer HEMA-[2-(methacryloyloxy)ethyl]trimethylammonium chloride (MOETACl), terpolymer HEMA-MANa-MOETACl and on a polyelectrolyte complex were used as carriers for immobilization of proteins, chicken egg white albumin and avidin. The adsorption capacity of the hydrogels for the two proteins, kinetics and pH dependence of albumin adsorption and desorption were studied. The morphology of the hydrogels with and without immobilized albumin was studied by low-vacuum scanning electron microscopy.

  18. Immobilization of denatured DNA to macroporous supports: II. Steric and kinetic parameters of heterogeneous hybridization reactions.

    OpenAIRE

    Bünemann, H

    1982-01-01

    The accessibility of immobilized DNA has been shown to depend more crucially on the method of immobilization than on the type of support used for fixation. When sonicated denatured DNA is coupled via diazotization or via cyanogen bromide reaction to solid Sephadex G-25 and Cellex 410 or to macroporous Sephacryl S-500 and Sepharose C1-6B its accessibility varies from 100 to 24 percent. Generally the loss of accessibility is linked to a depression of the melting temperature of DNA helices forme...

  19. Immobilization of denatured DNA to macroporous supports: I. Efficiency of different coupling procedures.

    OpenAIRE

    Bünemann, H; Westhoff, P; Herrmann, R. G.

    1982-01-01

    Methods commonly used for covalent immobilization of single stranded DNA have been applied to several solid supports (Sephadex G-25 and Cellex 410) as well as to a number of macroporous materials (Sepharose C1-6B, C1-2B; Sephacryl S-500 and S-1000). Coupling efficiencies and stability of covalently bound DNA are compared for both classes of materials. The yields of the immobilization reaction for sonicated DNA are only 10-40% for G-25 and Cellex 410 in contrast to 60-80% for C1-6B and S-500. ...

  20. Nanoporous walls on macroporous foam: rational design of electrodes to push areal pseudocapacitance

    Energy Technology Data Exchange (ETDEWEB)

    Guan, Cao; Fan, Hong Jin [Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University (Singapore); Energy Research Institute, NTU (ERIAN), Nanyang Technological University (Singapore); Li, Xianglin; Wang, Zilong; Soci, Cesare [Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University (Singapore); Cao, Xiehong; Zhang, Hua [School of Materials Science and Engineering, Nanyang Technological University (Singapore)

    2012-08-08

    For application as a pseudocapacitor electrode, highly porous CoO nanowalls are fabricated directly on 3D macroporous nickel foam (see images). A relatively high areal capacitance is achieved because of the porous structure. By grafting the porous nanowalls with another pseudocapacitive oxide, the areal capacitance can be further significantly boosted, owing to the increased surface area caused by the hierarchically porous structure as well as a possible synergetic effect between the two oxides. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  1. Enrichment and separation of chlorogenic acid from the extract of Eupatorium adenophorum Spreng by macroporous resin.

    Science.gov (United States)

    Liu, Boyan; Dong, Beitao; Yuan, Xiaofan; Kuang, Qirong; Zhao, Qingsheng; Yang, Mei; Liu, Jie; Zhao, Bing

    2016-01-01

    A simple and efficient chromatographic method for separation of chlorogenic acid from Eupatorium adenophorum Spreng extract was developed. The adsorption properties of nine macroporous resins were evaluated. NKA-II resin showed much better adsorption/desorption properties. The adsorption of chlorogenic acid on NKA-II resin at 25°C was well fitted to Langmuir isotherm model and pseudo-second-order kinetic model. The dynamic adsorption and desorption experiments were carried out on columns packed with NKA-II resin to optimize the separation process. The content of chlorogenic acid in the product increased to 22.17%, with a recovery yield of 82.41%.

  2. Quantification of small-scale physicochemical properties of intact macropore surfaces in Bt-horizons of Luvisols

    Science.gov (United States)

    Leue, Martin; Gerke, Horst H.

    2017-04-01

    During preferential flow in structured soils, the interaction of percolating water and reactive solutes with the soil matrix is mostly restricted to surfaces of preferential flow paths which affect mass exchange processes by the physical and chemical properties. These properties can strongly differ from bulk soil properties with respect to texture, organic matter (OM), pore geometry, density, and porosity. The aim of our work was to identify and to quantify effective macropore properties which concurrently are appropriate to represent physical mechanisms for entire soil horizons with respect to preferential flow. We studied physical and chemical properties of intact surfaces of soil aggregates, biopores (root channels, worm burrows), and coated cracks from Luvisol Bt-horizons. The spatial distribution of the OM composition and related physical properties such as wettability, the organic carbon content, and the cation exchange capacity of these macropores as characterized by DRIFT spectroscopy and complementary techniques were found spatially distributed at the mm-scale. Differences could be observed for loess and glacial till as parent materials, land use, and macropore types, in particular for cracks and biopores. The geometrical properties (pore volume, diameter, surfaces area, connectivity, and tortuosity) of all potentially available macropores, in particular the differences between cracks and biopores, were quantified in large soil columns using X-ray computed tomography (µCT). Dye tracer experiments at the cm-to-m-scale showed substrate-specific and macropore-specific differences between the active preferential flow paths. In a summarizing step we aim to combine the chemical and physical surface properties with the geometrical properties of the macropores in order to estimate the effects of the surface properties on preferential flow in Bt-horizons. The specific surface areas and chemical compositions may help explain differences in the staining patterns

  3. exploring traditional glass bead making techniques in jewellery

    African Journals Online (AJOL)

    User

    3Department of Integrated Rural Art and Industry, KNUST, Kumasi, Ghana ... processes involved which are mostly identified by the indigenous or traditional glass ... Glass bead making techniques and their mass production will help the ... resources are the ceramic or powdered pigment ..... container for washing (See Figs.

  4. Hydraulic and acoustic investigation of sintered glass beads

    Science.gov (United States)

    Gueven, Ibrahim; Luding, Stefan; Steeb, Holger

    2013-06-01

    In the present contribution, we are focussing on the hydraulical and acoustical charcterization of sintered glass beads. For the experiments sintered mono-and weakly polydisperse glass bead samples were applied. Depending on the particle size, degree of particle dispersion and sample treatment during the sintering process, the produced cylindircal samples exhibit different hydraulic and acoustic properties. The more general focus of our research lies on the physical behaviour of oil-water emulsions in porous media by means of combined electromagnetic and acoustic wave propagation. For this purpose, a hydraulic multi-task measuring cell was developed. This cell allows carrying out simple hydraulic permeability and challenging ultrasound experiments in porous materials saturated with Pickering emulsions. In the first phase of our experiments, hydraulical and acoustical measurements of cylindrical sintered glass bead samples were performed in order to determine their intrinsic permeabilities and effective ultrasound velocities. The intrinsic permeability ks, a coupling parameter between the solid matrix and the pore fluid, has a huge influence on wave propagation in fluid-saturated porous media. For the assessment of permeabilities, particle size distributions and porosities of the investigated glass beads were determined.

  5. Preparation and thermal properties of chitosan/bentonite composite beads

    Directory of Open Access Journals (Sweden)

    Teofilović Vesna

    2014-01-01

    Full Text Available Due to their biodegradable and nontoxic nature, biopolymer composites are often used as remarkable adsorbents in treatment of wastewater. In this study chitosan/bentonite composite beads were obtained by addition of clay into the polymer using solution process. Before the composite preparation, bentonite was modified with surfactant cetyltrimethyl ammonium bromide (CTAB. The morphology of beads was examined by scanning electron microscopy (SEM. Thermal properties of the composite beads were studied by simultaneous thermogravimetry coupled with differential scanning calorimetry (SDT and differential scanning calorimetry (DSC. TG results showed that the complex decomposition mechanism of the composites depends on the preparation procedure. It was observed that the concentration of NaOH used for composites precipitation affects the final structure of beads. The influence of preparation procedure on the glass transition temperature Tg of chitosan/bentonite samples was not found (Tg values for all samples were about 144 °C. [Projekat Ministarstva nauke Republike Srbije, br. III45022 and ON172014 and Provincial Secretariat of Vojvodina for Science and Technological Development 114-451-2396/2011-01.

  6. Collection Development: From Beads to Bangles (Jewelry Making)

    Science.gov (United States)

    Hanrahan, Katie

    2010-01-01

    Jewelry making began exploding as a hobby about ten years ago, largely because the flush economy gave individuals more leisure time and disposable income. Jewelry classes, bead stores, and special events have multiplied like craft shows at Christmas time. While the recent economic downturn has slowed the growth of the hobby, it is still as popular…

  7. Chitosan-Based Nanocomposite Beads for Drinking Water Production

    Science.gov (United States)

    Masheane, ML; Nthunya, LN; Sambaza, SS; Malinga, SP; Nxumalo, EN; Mamba, BB; Mhlanga, SD

    2017-05-01

    Potable drinking water is essential for the good health of humans and it is a critical feedstock in a variety of industries such as food and pharmaceutical industries. For the first time, chitosan-alumina/functionalised multiwalled carbon nanotube (f-MWCNT) nanocomposite beads were developed and investigated for the reduction of various physico-chemical parameters from water samples collected from open wells used for drinking purposes by a rural community in South Africa. The water samples were analysed before and after the reduction of the identified contaminants by the nanocomposite beads. The nanocomposite beads were effective in the removal of nitrate, chromium and other physico-chemical parameters. Although, the water samples contained these contaminants within the WHO and SANS241 limits for no risk, the long-term exposure and accumulation is an environmental and health concern. The reduction of these contaminants was dependent on pH levels. At lower pH, the reduction was significantly higher, up to 99.2% (SPC), 91.0% (DOC), 92.2% (DO), 92.2% (turbidity), 96.5% (nitrate) and 97.7% (chromium). Generally, the chitosan-alumina/f-MWCNT nanocomposite beads offer a promising alternative material for reduction and removal of various physico-chemical parameters for production portable water.

  8. Bead-Based Microfluidic Sediment Analogues: Fabrication and Colloid Transport.

    Science.gov (United States)

    Guo, Yang; Huang, Jingwei; Xiao, Feng; Yin, Xiaolong; Chun, Jaehun; Um, Wooyong; Neeves, Keith B; Wu, Ning

    2016-09-13

    Mobile colloids can act as carriers for low-solubility contaminants in the environment. However, the dominant mechanism for this colloid-facilitated transport of chemicals is unclear. Therefore, we developed a bead-based microfluidic platform of sediment analogues and measured both single and population transport of model colloids. The porous medium is assembled through a bead-by-bead injection method. This approach has the versatility to build both electrostatically homogeneous and heterogeneous media at the pore scale. A T-junction at the exit also allowed for encapsulation and enumeration of colloids effluent at single particle resolution to give population dynamics. Tortuosity calculated from pore-scale trajectory analysis and its comparison with lattice Boltzmann simulations revealed that transport of colloids was influenced by the size exclusion effect. The porous media packed by positively and negatively charged beads into two layers showed distinctive colloidal particle retention and significant remobilization and re-adsorption of particles during water flushing. We demonstrated the potential of our method to fabricate porous media with surface heterogeneities at the pore scale. With both single and population dynamics measurement, our platform has the potential to connect pore-scale and macroscale colloid transport on a lab scale and to quantify the impact of grain surface heterogeneities that are natural in the subsurface environment.

  9. Particle-like beads and daughter jet cascades in electrospinning

    Directory of Open Access Journals (Sweden)

    Li Haibin

    2013-01-01

    Full Text Available Nanofibers with high surface-to-volume ratio are of significant applications. This paper proposes a novel method for fabrication of particle-like beaded nanofibers and their daughter nanofibers, which are ejected from the surface of charged jets. Polyvinyl alcohol/ash solution is used in the electrospinning process.

  10. Antimicrobial N-brominated hydantoin and uracil grafted polystyrene beads.

    Science.gov (United States)

    Farah, Shady; Aviv, Oren; Laout, Natalia; Ratner, Stanislav; Domb, Abraham J

    2015-10-28

    Hydantoin-N-halamine derivatives conjugated on polystyrene beads are promising disinfectants with broad antimicrobial activity affected by the gradual release of oxidizing halogen in water. The objective of this work was to identify and test of hydantoin-like molecules possessing urea moiety, which may provide N-haloamines releasing oxidizing halogens when exposed to water at different rates and release profiles for tailored antimicrobial agents. In this work, several hydantoin (five member ring) and for the first time reported, uracil (six member ring) derivatives have been conjugated to polystyrene beads and tested for their lasting antimicrobial activity. Four molecules of each series were conjugated onto polystyrene beads from the reaction of the N-potassium hydantoin or uracil derivatives onto chloromethylated polystyrene beads. A distinct difference in bromine loading capacity and release profiles was found for the different conjugated derivatives. All tested materials exhibit strong antimicrobial activity against Escherichia coli and bacteriophages MS2 of 7 and ~4 log reduction, respectively. These results highlight the antimicrobial potential of halogenated cyclic molecules containing urea groups as water disinfection agents.

  11. Quantum-dot-tagged photonic crystal beads for multiplex detection of tumor markers.

    Science.gov (United States)

    Li, Juan; Wang, Huan; Dong, Shujun; Zhu, Peizhi; Diao, Guowang; Yang, Zhanjun

    2014-12-04

    Novel quantum-dot-tagged photonic crystal beads were fabricated for multiplex detection of tumor markers via self-assembly of quantum dot-embedded polystyrene nanospheres into photonic crystal beads through a microfluidic device.

  12. Protein separation and identification using magnetic beads encoded with surface-enhanced Raman spectroscopy.

    Science.gov (United States)

    Jun, Bong-Hyun; Noh, Mi Suk; Kim, Gunsung; Kang, Homan; Kim, Jong-Ho; Chung, Woo-Jae; Kim, Min-Soo; Kim, Yong-Kweon; Cho, Myung-Haing; Jeong, Dae Hong; Lee, Yoon-Sik

    2009-08-01

    This article presents a prototype of a surface-enhanced Raman spectroscopy (SERS)-encoded magnetic bead of 8mum diameter. The core part of the bead is composed of a magnetic nanoparticle (NP)-embedded sulfonated polystyrene bead. The outer part of the bead is embedded with Ag NPs on which labeling molecules generating specific SERS bands are adsorbed. A silica shell is fabricated for further bioconjugation and protection of SERS signaling. Benzenethiol, 4-mercaptotoluene, 2-naphthalenethiol, and 4-aminothiophenol are used as labeling molecules. The magnetic SERS beads are used as substrates for protein sensing and screening with easy handling. As a model application, streptavidin-bound magnetic SERS beads are used to illustrate selective separation in a flow cytometry system, and the screened beads are spectrally recognized by Raman spectroscopy. The proposed magnetic SERS beads are likely to be used as a versatile solid support for protein sensing and screening in multiple assay technology.

  13. Pyrolytic sugars from cellulosic biomass

    Science.gov (United States)

    Kuzhiyil, Najeeb

    Sugars are the feedstocks for many promising advanced cellulosic biofuels. Traditional sugars derived from starch and sugar crops are limited in their availability. In principle, more plentiful supply of sugars can be obtained from depolymerization of cellulose, the most abundant form of biomass in the world. Breaking the glycosidic bonds between the pyranose rings in the cellulose chain to liberate glucose has usually been pursued by enzymatic hydrolysis although a purely thermal depolymerization route to sugars is also possible. Fast pyrolysis of pure cellulose yields primarily levoglucosan, an anhydrosugar that can be hydrolyzed to glucose. However, naturally occurring alkali and alkaline earth metals (AAEM) in biomass are strongly catalytic toward ring-breaking reactions that favor formation of light oxygenates over anhydrosugars. Removing the AAEM by washing was shown to be effective in increasing the yield of anhydrosugars; but this process involves removal of large amount of water from biomass that renders it energy intensive and thereby impractical. In this work passivation of the AAEM (making them less active or inactive) using mineral acid infusion was explored that will increase the yield of anhydrosugars from fast pyrolysis of biomass. Mineral acid infusion was tried by previous researchers, but the possibility of chemical reactions between infused acid and AAEM in the biomass appears to have been overlooked, possibly because metal cations might be expected to already be substantially complexed to chlorine or other strong anions that are found in biomass. Likewise, it appears that previous researchers assumed that as long as AAEM cations were in the biomass, they would be catalytically active regardless of the nature of their complexion with anions. On the contrary, we hypothesized that AAEM can be converted to inactive or less active salts using mineral acids. Various biomass feedstocks were infused with mineral (hydrochloric, nitric, sulfuric and

  14. Adsorption Mechanism of Macroporous Adsorption Resins%大孔吸附树脂的吸附机理

    Institute of Scientific and Technical Information of China (English)

    娄嵩; 刘永峰; 白清清; 邸多隆

    2012-01-01

    大孔吸附树脂(macroprous adsorption resin,MAR)是近几十年发展起来的一种具有多孔立体结构、人工合成的有机高分子聚合物。由于其特殊的理化性质和吸附性能,已被广泛应用于化学、医药、环保和食品等领域。本文介绍了近年来国内外对大孔吸附树脂在吸附机理研究方面的进展,重点介绍了不同温度条件下大孔吸附树脂对靶标分子的吸附热力学行为模式,靶标分子在大孔吸附树脂表面及孔内的吸附扩散行为模式。此外,大孔吸附树脂性能参数和靶标分子结构参数之间构效关系也对其吸附选择性规律具有重要的影响。因此,大孔吸附树脂与底物间构效关系的匹配程度及其对选择性的影响是大孔吸附树脂分离理论研究的核心。本文最后介绍了可以准确客观描述吸附过程并具有一定使用范围的大孔吸附树脂吸附模型的建立和评价。%Macroporous adsorption resins (MARs) , which are synthetic porous crosslinked polymer beads, have been developed into a kind of novel functional materials since 1950' They have widely been used in the fields such as pharmaceutical, chemical, food industries, and wastewater treatment. Besides the traditional research on applications of the commercial MARs in the enrichment process of target compound, some theoretical researches on the adsorption features of MARs are also introduced in this article, including adsorption isotherms, kinetics, driving forces, and interaction models. First, the adsorption isotherm patterns of target compound on MARs are discussed. Second, the diffusion patterns of targets on the surface and internal MARs are illustrated. The relationship between properties of MARs and structures of target compound effects the law of adsorption selection,and the investigation of this relationship is the key problem of theoretical research on separation and adsorption. Moreover, the ultimate purpose of

  15. Potential use of scrap expanded polystyrene beads for the control of Aedes triseriatus.

    Science.gov (United States)

    Beehler, J W; DeFoliart, G R

    1991-06-01

    The potential use of expanded polystyrene (EPS) beads for control of Aedes triseriatus was tested in the laboratory and the field. Laboratory studies showed that beads present in amounts which persisted throughout a season significantly reduced the emergence of Ae. triseriatus adults by preventing normal eclosion from the pupae. In the field, tree holes containing EPS beads had significantly fewer larvae present than untreated controls. These field data suggest that EPS beads may mechanically prevent oviposition by mosquitoes.

  16. Comparison of physical properties of regenerated cellulose films fabricated with different cellulose feedstocks in ionic liquid.

    Science.gov (United States)

    Pang, JinHui; Wu, Miao; Zhang, QiaoHui; Tan, Xin; Xu, Feng; Zhang, XueMing; Sun, RunCang

    2015-05-05

    With the serious "white pollution" resulted from the non-biodegradable plastic films, considerable attention has been directed toward the development of renewable and biodegradable cellulose-based film materials as substitutes of petroleum-derived materials. In this study, environmentally friendly cellulose films were successfully prepared using different celluloses (pine, cotton, bamboo, MCC) as raw materials and ionic liquid 1-ethyl-3-methylimidazolium acetate as a solvent. The SEM and AFM indicated that all cellulose films displayed a homogeneous and smooth surface. In addition, the FT-IR and XRD analysis showed the transition from cellulose I to II was occurred after the dissolution and regeneration process. Furthermore, the cellulose films prepared by cotton linters and pine possessed the most excellent thermal stability and mechanical properties, which were suggested by the highest onset temperature (285°C) and tensile stress (120 MPa), respectively. Their excellent properties of regenerated cellulose films are promising for applications in food packaging and medical materials.

  17. Speculations on the nature of cellulose pyrolysis

    Science.gov (United States)

    F.J. Kilzer; A. Broido

    1965-01-01

    Consideration of the available data on cellulose pyrolysis suggests that, with relative importance depending upon heating rate in the temperature range 200-400°C, very pure cellulose decomposes by two competitive endothermic processes. lt is postulated that an unzipping reaction produces 1,4-anhydro-α-D-glucopyranose which rearranges to give levoglucosan. The other...

  18. Idealized powder diffraction patterns for cellulose polymorphs

    Science.gov (United States)

    Cellulose samples are routinely analyzed by X-ray diffraction to determine their crystal type (polymorph) and crystallinity. However, the connection is seldom made between those efforts and the crystal structures of cellulose that have been determined with synchrotron X-radiation and neutron diffrac...

  19. Nucleic acids encoding a cellulose binding domain

    Energy Technology Data Exchange (ETDEWEB)

    Shoseyov, Oded (Karmey Yosef, IL); Shpiegl, Itai (Rehovot, IL); Goldstein, Marc A. (Davis, CA); Doi, Roy H. (Davis, CA)

    1996-01-01

    A cellulose binding domain (CBD) having a high affinity for crystalline cellulose and chitin is disclosed, along with methods for the molecular cloning and recombinant production thereof. Fusion products comprising the CBD and a second protein are likewise described. A wide range of applications are contemplated for both the CBD and the fusion products, including drug delivery, affinity separations, and diagnostic techniques.

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

    Directory of Open Access Journals (Sweden)

    George J

    2015-11-01

    Full Text Available Johnsy George, SN Sabapathi Food Engineering and Packaging Division, Defence Food Research Laboratory, Siddarthanagar, Mysore, Karnataka, India Abstract: Cellulose nanocrystals are unique nanomaterials derived from the most abundant and almost inexhaustible natural polymer, cellulose. These nanomaterials have received significant interest due to their mechanical, optical, chemical, and rheological properties. Cellulose nanocrystals primarily obtained from naturally occurring cellulose fibers are biodegradable and renewable in nature and hence they serve as a sustainable and environmentally friendly material for most applications. These nanocrystals are basically hydrophilic in nature; however, they can be surface functionalized to meet various challenging requirements, such as the development of high-performance nanocomposites, using hydrophobic polymer matrices. Considering the ever-increasing interdisciplinary research being carried out on cellulose nanocrystals, this review aims to collate the knowledge available about the sources, chemical structure, and physical and chemical isolation procedures, as well as describes the mechanical, optical, and rheological properties, of cellulose nanocrystals. Innovative applications in diverse fields such as biomedical engineering, material sciences, electronics, catalysis, etc, wherein these cellulose nanocrystals can be used, are highlighted. Keywords: sources of cellulose, mechanical properties, liquid crystalline nature, surface modification, nanocomposites 

  1. 21 CFR 172.870 - Hydroxypropyl cellulose.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Hydroxypropyl cellulose. 172.870 Section 172.870... CONSUMPTION Multipurpose Additives § 172.870 Hydroxypropyl cellulose. The food additive hydroxypropyl... anhydrous basis, not more than 4.6 hydroxypropyl groups per anhydroglucose unit. The additive has a...

  2. Conformational studies of cellulosic fragments by DFT

    Science.gov (United States)

    The study of cellulosic fragments by DFTr is a continuation of our efforts to produce quality structural data that will be valuable to those working in the field of cellulose structure and enzymatic degradation. Using a reduced basis set and density functional DFTr (B3LYP), optimization of cellulosi...

  3. Characterization of cellulose nanofibrillation by micro grinding

    Science.gov (United States)

    Sandeep S. Nair; J.Y. Zhu; Yulin Deng; Arthur J. Ragauskas

    2014-01-01

    A fundamental understanding of the morphological development of cellulose fibers during fibrillation using micro grinder is very essential to develop effective strategies for process improvement and to reduce energy consumption. We demonstrated some simple measures for characterizing cellulose fibers fibrillated at different fibrillation times through the grinder. The...

  4. Diffraction from nonperiodic models of cellulose crystals

    Science.gov (United States)

    Powder and fiber diffraction patterns were calculated for model cellulose crystallites with chains 20 glucose units long. Model sizes ranged from four chains to 169 chains, based on cellulose I' coordinates, and were subjected to various combinations of energy minimization and molecular dynamics (M...

  5. A mathematical model for the formation of beaded fibers in electrospinning

    Directory of Open Access Journals (Sweden)

    Liu Zhi

    2015-01-01

    Full Text Available Beaded fibers are often observed in electrospinning. However, its formation mechanism is not well understood. A mathematical model for pulsation of the charged jets during spinning is proposed to reveal the phenomenon of beaded fibers, and the main factors for beaded fibers are elucidated.

  6. Bead Capture and Release on a Magnetic Sensor in a Microfluidic System

    DEFF Research Database (Denmark)

    Dalslet, Bjarke Thomas; Damsgaard, Christian Danvad; Freitas, S.C.

    Planar Hall effect magnetic sensors for detection of biological agents using surface treated magnetic beads are integrated with a fluid injection system. The response of the sensors is used to evaluate bead capture rates for different bead concentrations c and fluid flow rates Q, and to monitor s...

  7. Rheological Modeling with Hookean Bead-Spring Cubes (SC, BBC and FCC)

    NARCIS (Netherlands)

    Denneman, A.I.M.; Jongschaap, R.J.J.; Mellema, J.

    1998-01-01

    In this study a general bead-spring model is used for predicting some rheological properties of a cubic bead-spring structure of arbitrary size immersed in a Newtonian solvent. The topology of this bead-spring structure is based upon the well-known cubic crystals (SC, BCC or FCC) and it consists of

  8. Chemical–physical characterisation of Early Iron Age glass beads from Central Europe

    Directory of Open Access Journals (Sweden)

    Fernando Agua

    2017-05-01

    Additionally, results showed microstructural and microcrystalline differences between some glass beads studied here and other glass beads from Mediterranean areas, dated in the same chronological period. This fact pointed out the valuable role given to these beads by Iron Age communities from Central Europe.

  9. Delivery of ibuprofen by natural macroporous sporopollenin exine capsules extracted from Phoenix dactylifera L.

    Science.gov (United States)

    Alshehri, Saad M; Al-Lohedan, Hamad A; Chaudhary, Anis Ahmad; Al-Farraj, Eida; Alhokbany, Norah; Issa, Zuheir; Alhousine, Sami; Ahamad, Tansir

    2016-06-10

    Sporopollenin macroporous capsules (SMCs) were extracted from date palm (Phoenix dactylifera L.) spores and coated by a natural polymer composite (chitosan with glutaraldehyde). The polymer coated macroporous capsules SMC@poly were used in the in vitro-controlled delivery of ibuprofen. The materials obtained were characterized through spectral, thermal, scanning electron microscopy (SEM), X-ray diffraction (XRD), and nitrogen adsorption-desorption isotherms. The IBU loading and releasing was studied by investigating the changes in various factors such as pH, temperature, and initial concentration. The results revealed that the loading of IBU increased when the concentration of IBU was decreased, following the Langmuir adsorption isotherm. The maximum loading of the IBU was observed at pH6.0 (97.2%, with 50mg/mL). The releasing results indicate that IBU was released faster when the pH was changed from 1.4 to 7.4. In addition, the cytotoxicity of the SMC, SMC@poly, and SMC@poly-IBU were tested against human intestinal Caco-2 cell line using MTT assay, and the results revea'led that all the materials in this study were biocompatible.

  10. Detachment of affinity-captured bioparticles by elastic deformation of a macroporous hydrogel

    Science.gov (United States)

    Dainiak, Maria B.; Kumar, Ashok; Galaev, Igor Yu.; Mattiasson, Bo

    2006-01-01

    Adsorption of bioparticles to affinity surfaces involves polyvalent interactions, complicating greatly the recovery of the adsorbed material. A unique system for the efficient binding and release of different cells and particles is described. Affinity-bound bioparticles and synthetic particles are detached from the macroporous hydrogel matrix, a so-called cryogel, when the cryogel undergoes elastic deformation. The particle detachment upon elastic deformation is believed to be due to breaking of many of the multipoint attachments between the particles and the affinity matrix and the change in the distance between affinity ligands when the matrix is deformed. However, no release of affinity-bound protein occurred upon elastic deformation. The phenomenon of particle detachment upon elastic deformation is believed to be of a generic nature, because it was demonstrated for a variety of bioparticles of different sizes and for synthetic particles, for different ligand–receptor pairs (IgG–protein A, sugar–ConA, metal ion–chelating ligand), and when the deformation was caused by either external forces (mechanical deformation) or internal forces (the shrinkage of thermosensitive, macroporous hydrogel upon an increase in temperature). The elasticity of cryogel monoliths ensures high recovery of captured cells under mild conditions, with highly retained viability. This property, along with their continuous porous structure makes cryogel monoliths very attractive for applications in affinity cell separation. PMID:16418282

  11. Tension free monofilament macropore polypropylene mesh (Gynemesh PS in female genital prolapse repair

    Directory of Open Access Journals (Sweden)

    Vicente Sola

    2006-08-01

    Full Text Available OBJECTIVES: To review intraoperative and postoperative complications associated to the correction of cystocele and rectocele with polypropylene mesh macropore monofilament (Gynemesh PS using transvaginal free tension technique. MATERIALS AND METHODS: Prospective study of patients that have been submitted to correction of cystocele and/or rectocele between November 2004 and August 2005 in the Urogynecology and Vaginal Surgery Unit of Gynecology and Obstetrics Department, Las Condes Clinic. Mesh was used in 31 patients: 9 for cystocele, 11 for rectocele, and 11 for concomitant meshes. Total mesh used 42. Media age 55 years old, weight 64 kilograms. In 7 patients we used a third mesh for correction of urinary incontinence by TVT-O technique. RESULTS: They did not present intraoperative complications, neither in immediate or delayed postoperative time. We did not observe hematoma, infection, erosion or exposition mesh. Healing of cystocele and rectocele was obtained in 100% of patients, with a pursuit between 1 and 8 months. DISCUSSION: The use of prosthetic polypropylene monofilament macropore mesh in the correction of cystocele and/or rectocele, by transvaginal route with tension free technique seems to be a safe and effective surgery procedure.

  12. Sapropel-based supports as novel macroporous carbon-mineral adsorbents for enzymatic active substances

    Directory of Open Access Journals (Sweden)

    G.A. Kovalenko

    2016-12-01

    Full Text Available The novel macroporous carbon-mineral Sapropel supports were obtained from lacustrine sapropel silts of freshwater lakes by annealing of semi-coke in the inert atmosphere. The specific surface area of these supports varied from 10 to 100 m2/g, the total pore volume from 0.3 cm3/g till 1.6 cm3/g; macropores of diameters more than 2 µm were predominating. The Sapropel supports were studied for the adsorption/adhesion of enzymatic active substances, such as whole bacterial cells, and invertase-active fully destroyed baker's yeast cells (autolysates, and purified enzyme nitrilase. The heterogeneous biocatalysts with required enzymatic activity were prepared and their properties were studied in the corresponding bioconversion processes. The invertase-active biocatalysts exhibited high activity, 120–135 U/g, and stability; the half-times of their inactivation (t½ were more than 1000 h in the continuous process of sucrose hydrolysis at 50 °C. The nitrilase-active biocatalysts for “green” chemistry of nitriles possessed high activity, 350–500 U/g, and the t½ were estimated to be more than 100 h in the periodic process of hydration of acrylonitrile to acrylic acid at 22 °C.

  13. Preparative separation of echinocandin B from Aspergillus nidulans broth using macroporous resin adsorption chromatography.

    Science.gov (United States)

    Zou, Shu-Ping; Liu, Miao; Wang, Qiu-Liang; Xiong, Yan; Niu, Kun; Zheng, Yu-Guo; Shen, Yin-Chu

    2015-01-26

    Echinocandin B (ECB), an echinocandin type of lipopeptide antibiotic produced by Aspergillus nidulans, is a precursor for the synthesis of novel anti-fungal drug - anidulafungin. In this work, a separation strategy involving one-step macroporous resin adsorption chromatography was established for ECB purification from Aspergillus nidulans CCTCC M 2010275 fermentation broth. Among nine macroporous resin adsorbents tested, the non-polar resin HP-20 had the best adsorption and desorption performance. The static equilibrium adsorption data fitted well with the Langmuir equation, and the adsorption kinetic followed the pseudo-second order model. The separation parameters of ECB from broth were optimised by dynamic adsorption/desorption experiments with the column packed with HP-20 resin. Under optimal conditions, the purity increased by 3.8-fold from 23.2% in broth to 88.5% in eluent with 87.1% recovery yield by a one-step treatment. Our study provided a one-step and effective method for large-scale production of ECB, and offered references for separating other echinocandins from broth. Copyright © 2014 Elsevier B.V. All rights reserved.

  14. Preparative Separation and Purification of the Total Flavonoids in Scorzonera austriaca with Macroporous Resins.

    Science.gov (United States)

    Xie, Yang; Guo, Qiu-Shi; Wang, Guang-Shu

    2016-06-13

    The use of macroporous resins for the separation and purification of total flavonoids to obtain high-purity total flavonoids from Scorzonera austriaca was studied. The optimal conditions for separation and purification of total flavonoids in S. austriaca with macroporous resins were as follows: D4020 resin columns were loaded with crude flavonoid extract solution, and after reaching adsorptive saturation, the columns were eluted successively with 5 bed volumes (BV) of water, 5 BV of 5% (v/v) aqueous ethanol and 5 BV of 30% (v/v) aqueous ethanol at an elute flow rate of 2 BV·h(-1). Total flavonoids were obtained from the 30% aqueous ethanol eluate by vacuum distillation recovery. The content of flavonoid compounds in the total flavonoids was 93.5%, which represents an improvement by about 150%. In addition, five flavonoid compounds in the product were identified as 2″-O-β-d-xylopyranosyl isoorientin, 6-C-α-l-arabipyranosyl orientin, orientin, isoorientin and vitexin by LC-ESI-MS analysis and internal standard methods. The results in this study could represent a method for the large-scale production of total flavonoids from S. austriaca.

  15. Preparative Separation and Purification of the Total Flavonoids in Scorzonera austriaca with Macroporous Resins

    Directory of Open Access Journals (Sweden)

    Yang Xie

    2016-06-01

    Full Text Available The use of macroporous resins for the separation and purification of total flavonoids to obtain high-purity total flavonoids from Scorzonera austriaca was studied. The optimal conditions for separation and purification of total flavonoids in S. austriaca with macroporous resins were as follows: D4020 resin columns were loaded with crude flavonoid extract solution, and after reaching adsorptive saturation, the columns were eluted successively with 5 bed volumes (BV of water, 5 BV of 5% (v/v aqueous ethanol and 5 BV of 30% (v/v aqueous ethanol at an elute flow rate of 2 BV·h−1. Total flavonoids were obtained from the 30% aqueous ethanol eluate by vacuum distillation recovery. The content of flavonoid compounds in the total flavonoids was 93.5%, which represents an improvement by about 150%. In addition, five flavonoid compounds in the product were identified as 2″-O-β-d-xylopyranosyl isoorientin, 6-C-α-l-arabipyranosyl orientin, orientin, isoorientin and vitexin by LC-ESI-MS analysis and internal standard methods. The results in this study could represent a method for the large-scale production of total flavonoids from S. austriaca.

  16. Separation and Purification of Two Flavone Glucuronides from Erigeron multiradiatus (Lindl. Benth with Macroporous Resins

    Directory of Open Access Journals (Sweden)

    Zhi-feng Zhang

    2009-01-01

    Full Text Available Scutellarein-7-O-β-D-glucuronide (SG and apigenin-7-O-β-D-glucuronide (AG are two major bioactive constituents with known pharmacological effects in Erigeron multiradiatus. In this study, a simple method for preparative separation of the two flavone glucuronides was established with macroporous resins. The performance and adsorption characteristics of eight macroporous resins including AB-8, HPD100, HPD450, HPD600, D100, D101, D141, and D160 have been evaluated. The results confirmed that D141 resin offered the best adsorption and desorption capacities and the highest desorption ratio for the two glucuronides among the tested resins. Sorption isotherms were constructed for D141 resin under optimal ethanol conditions and fitted well to the Freundlich and Langmuir models (R2>0.95. Dynamic adsorption and desorption tests was performed on column packed with D141 resin. After one-run treatment with D141 resin, the two-constituent content in the final product was increased from 2.14% and 1.34 % in the crude extract of Erigeron multiradiatus to 24.63% and 18.42% in the final products with the recoveries of 82.5% and 85.4%, respectively. The preparative separation of SG and AG can be easily and effectively achieved via adsorption and desorption on D141 resin, and the method developed can be referenced for large-scale separation and purification of flavone glucuronides from herbal raw materials.

  17. Preparation of macroporous methacrylate-based monoliths for chromatographic applications by the Reactive Gelation Process.

    Science.gov (United States)

    Bechtle, M; Butté, A; Storti, G; Morbidelli, M

    2010-07-09

    Polymeric monoliths are a relatively new separation medium for chromatographic applications. The innovative approach to produce such monoliths, the Reactive Gelation Process, presented by Marti et al. [1] for polystyrene macroporous materials is applied to a methacrylate-based material. It is shown that it is possible to create a macroporous structure by Reactive Gelation also with this polymer even if the properties of the material are different. Besides the analysis of the material by SEM and BET, several chromatographic methods are used to analyze the material properties. The ISEC experiments showed a much smaller size exclusion effect than in conventional packed beds. The permeability of the material is comparable to a packed bed with 4.13 μm particles. The column efficiency is not changing for increasing flow rates. Because of the high efficiency of the material, shorter columns are needed and therefore the comparatively low permeability is compensated. The monolith also exhibits a significant adsorption capacity for hydrophobic interaction, which makes it suitable for chromatographic purification processes.

  18. A composite chitosan-gelatin bi-layered, biomimetic macroporous scaffold for blood vessel tissue engineering.

    Science.gov (United States)

    Badhe, Ravindra V; Bijukumar, Divya; Chejara, Dharmesh R; Mabrouk, Mostafa; Choonara, Yahya E; Kumar, Pradeep; du Toit, Lisa C; Kondiah, Pierre P D; Pillay, Viness

    2017-02-10

    A composite chitosan-gelatin macroporous hydrogel-based scaffold with bi-layered tubular architecture was engineered by solvent casting-co-particulate leaching. The scaffold constituted an inner macroporous layer concealed by a non-porous outer layer mimicking the 3D matrix of blood vessels with cellular adhesion and proliferation. The scaffold was evaluated for its morphological, physicochemical, physicomechanical and biodurability properties employing SEM, FTIR, DSC, XRD, porositometry, rheology and texture analysis. The fluid uptake and biodegradation in the presence of lysozymes was also investigated. Cellular attachment and proliferation was analysed using human dermal fibroblasts (HDF-a) seeded onto the scaffold and evaluated by MTT assay, SEM, and confocal microscopy. Results demonstrated that the scaffold had a desirable tensile strength=95.81±11kPa, elongation at break 112.5±13%, porosity 82% and pores between 100 and 230μm, 50% in vitro biodegradation at day 16 and proliferated fibroblasts over 20 days. These results demonstrate that scaffold may be an excellent tubular archetype for blood vessel tissue engineering.

  19. Ground Organic Monolith Particles Having a Large Volume of Macropores as Chromatographic Separation Media

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jin Wook; Ali, Faiz; Kim, Yune Sung; Cheong, Won Jo [Inha Univ., Incheon (Korea, Republic of)

    2014-07-15

    A reaction mixture was developed for formation of soft organic monolith that was easily smashed, rinsed, refluxed, filtered, and dried to give monolith particles having high pore volume of macropores. This phase was almost without mesopores. The reaction mixture was composed of methacrylic acid, ethylene glycol dimethacrylate, polyethylene glycol (porogen), and an initiator in a mixed solvent of toluene and isooctane. The selection of porogen and its amount was carefully carried out to obtain the optimized separation efficiency of the resultant phase. The median macropore size was 1.6 μm, and the total pore volume was 3.0-3.4 mL/g. The median particle size (volume based) was 15 μm, and the range of particle size distribution was very broad. Nevertheless the column (1 Χ 300 mm) packed with this phase showed good separation efficiency (N∼10,000-16,000) comparable to that of a commercial column packed with 5 μm C18 silica particles.

  20. Immobilization of denatured DNA to macroporous supports: II. Steric and kinetic parameters of heterogeneous hybridization reactions.

    Science.gov (United States)

    Bünemann, H

    1982-11-25

    The accessibility of immobilized DNA has been shown to depend more crucially on the method of immobilization than on the type of support used for fixation. When sonicated denatured DNA is coupled via diazotization or via cyanogen bromide reaction to solid Sephadex G-25 and Cellex 410 or to macroporous Sephacryl S-500 and Sepharose C1-6B its accessibility varies from 100 to 24 percent. Generally the loss of accessibility is linked to a depression of the melting temperature of DNA helices formed on the support. This correlation shows a characteristic course for a particular coupling method. DNA coupled under denaturing conditions may become totally inaccessible when only 3 percent of its bases are involved in the covalent linkage. Kinetic experiments with sonicated E.coli DNA have shown that the rate constants for renaturation or hybridization reactions are very similar for DNA immobilized by different methods to solid or macroporous supports. Generally the second order rate constant for a heterogeneous reaction (between mobile and immobilized DNA) is about one order of magnitude smaller than that of the analogous homogeneous reaction (in solution).

  1. EFFECTS OF DIFFUSION ON THE KINETICS OF MALTOSE HYDROLYSIS USING GLUCOAMYLASE IMMOBILIZED ON MACROPOROUS SILICA

    Directory of Open Access Journals (Sweden)

    L.R.B. Gonçalves

    1997-12-01

    Full Text Available In this work the effects of diffusion on the hydrolysis of maltose using glucoamylase immobilized on macroporous silica at 30o C are studied. Two different kinds of experimental assays are carried out: one using free enzyme and the other using an enzyme covalently linked to macroporous silica, preactivated with glutaraldehyde. Free enzyme assays are used to estimate the kinetic parameters for hydrolysis of maltose at 30ºC, according to a Michaelis-Menten equation, with inhibition by the product. Runs with the immobilized enzyme enable us to estimate dextrin diffusivities in silica, assuming that the inherent kinetic parameters are equal to the intrinsic ones. The values of kinetic and mass transfer parameters are: K3 = 0.90x10-5 g/U.s, Km = 0.61x10-3 g/ml, Ki = 1.23x10-1 g/ml, DMs = 0.50x10-6 cm2 /s and DGs = 0.55x10-6 cm2 /s

  2. Radiation pretreatment of cellulose for energy production

    Science.gov (United States)

    Dela Rosa, A. M.; Dela Mines, A. S.; Banzon, R. B.; Simbul-Nuguid, Z. F.

    The effect of radiation pretreatment of agricultural cellulosic wastes was investigated through hydrolytic reactions of cellulose. Gamma irradiation significantly increased the acid hydrolysis of rice straw, rice hull and corn husk. The yields of reducing sugar were higher with increasing radiation dose in these materials. The observed radiation effect varied with the cellulosic material but it correlated with neither the cellulose content nor the lignin content. Likewise, the radiation pretreatment accelerated the subsequent enzymatic hydrolysis of rice straw and rice hull by cellulase. The irradiated rice straw appeared to be a better growth medium for the cellulolytic microorganism, Myrothecium verrucaria, than the non-irradiated material. This was attributed to increased digestibility of the cellulose by the microorganism.

  3. BIODEGRADATION OF REGENERATED CELLULOSE FILMS BY FUNGI

    Institute of Scientific and Technical Information of China (English)

    ZHANG Lina; LIU Haiqing; ZHENG Lianshuang; ZHANG Jiayao; DU Yumin; LIU Weili

    1996-01-01

    The biodegradability of Aspergillus niger (A. niger), Mucor (M-305) and Trichoderma (T-311) strains on regenerated cellulose films in media was investigated. The results showed that T-311 strain isolated from soil adhered on the cellulose film fragments has stronger degradation effect on the cellulose film than A. niger strain. The weights, molecular weights and tensile strengths of the cellulose films in both shake culture and solid media decreased with incubation time, accompanied by producing CO2 and saccharides. HPLC, IR and released CO2 analysis indicated that the biodegradation products of the regenerated cellulose films mainly contain oligosaccharides, cellobiose, glucose, arabinose, erythrose, glycerose,glycerol, ethanal, formaldehyde and organic acid, the end products were CO2 and water.After a month, the films were completely decomposed by fungi in the media at 30℃.

  4. Preparation of cellulose from corncobs I: Study on cellulose extraction

    Directory of Open Access Journals (Sweden)

    Pongnoree, J.

    2006-01-01

    Full Text Available The extraction of fat from corncob powder was determined using hexane and 95% ethanol solution for 4, 8 and 12 hrs. The selected powder was subjected to protein separation using 10, 15 and 20% NaOH for 15, 30 and 45 min. The obtained product was then bleached using 10, 15 and 20% H2O2 for 1.5, 3.0 and 4.5 hrs. It was found that the suitable condition for fat extraction was using 95% ethanol for 8 hrs. The optimal condition for protein extraction was using 15% NaOH for 30 min. and the bleaching condition was using 10% H2O2 for 1.5 hrs. The obtained product contained 76.90% cellulose (dry basis and the chemical composition and physical properties were also determined.

  5. Electrochemical impedance spectroscopy in chromatography paper and its application to latex bead detection

    Science.gov (United States)

    Iwahara, Shohei; Miki, Masashi; Hori, Fumitaka; Uno, Shigeyasu

    2014-01-01

    The principle of the quantitative immunochromatographic strip test (IST) is proposed. Electrochemical impedance spectroscopy is shown to be capable of detecting latex beads in chromatography paper, where latex beads can serve as a label in IST. Measurements to examine the impedance changes in the absence and presence of latex beads are conducted. In the presence of latex beads, an increase of 12.5% in the bulk solution resistance is observed. This indicates that the latex-bead-labeled antigen-antibody complex can be detected electrochemically by actual IST.

  6. Lattice Boltzmann Modeling of Macro-Porous Flow: Effects of Image Segmentation Algorithms and Comparisons with Observed Data

    Science.gov (United States)

    In this presentation we simulate saturated flow through macroporous soil columns (7.62x18 cm) with a lattice Boltzmann model and compare results with measured saturated hydraulic conductivities. Porous geometry was obtained with an industrial CT scanner yielding a resolution of 119 microns (656x656x...

  7. One-step preparation of macroporous polymer particles with multiple interconnected chambers: a candidate for trapping biomacromolecules.

    Science.gov (United States)

    Qian, Qiuping; Huang, Xiaopeng; Zhang, Xinyue; Xie, Zhigang; Wang, Yapei

    2013-09-27

    Taking advantage of photothermal conversion, the surface pores of water-dispersible single-walled carbon nanotubes assembled on polymer particles were rapidly closed by NIR irradiation to produce macroporous polymeric microspheres with multiple interconnected chambers. These particles can act as smart containers to encapsulate and hold DNA molecules.

  8. Scalable synthesis of hierarchical macropore-rich activated carbon microspheres assembled by carbon nanoparticles for high rate performance supercapacitors

    Science.gov (United States)

    Zhang, Dongdong; Zhao, Jianghong; Feng, Chong; Zhao, Rijie; Sun, Yahui; Guan, Taotao; Han, Baixin; Tang, Nan; Wang, Jianlong; Li, Kaixi; Qiao, Jinli; Zhang, Jiujun

    2017-02-01

    A scalable inverse-microemulsion-polymerization-phase-separation coupling method is applied to successfully prepare hierarchical macropore-rich activated carbon microspheres (ACS) using a phenolic resin (PR) precursor followed by carbonization and KOH activation for the first time. The formed ACS materials are assembled by carbon nanoparticles (CNPs). The macropores interspersed among the component CNPs are formed after removing the non-reactive solvent phase in the course of the polymerization of the reactive PR phase, which occupies ∼64% of the total pore volume (∼2.779 cm3 g-1) of the optimized ACS. In combination with mesopores (∼18% of the total pore volume), the ACS possesses meso/macropores approaching 82% of the total pore volume. Micropores are created in the component CNPs via KOH activation, showing shortened ion transport distances in the nanoscale dimension. Both the hierarchical micro/meso/macroporous structure and the inner nanoparticle morphology (short ion diffusion pathways) can significantly contribute to the rapid transport of electrolyte ions throughout the carbonaceous matrix, resulting in superior rate performance of ACS-based supercapacitors. More importantly, the energy densities of the ACS supercapacitors operating in both aqueous and organic electrolyte retain steady over a wide range of power densities varying dramatically from 0.25 to 14.5 kW kg-1 and to 7.0 kW kg-1, respectively.

  9. Macroporous poly(glycidyl methacrylate-co-ethylene glycol dimethacrylate) resins-Versatile immobilization supports for biocatalysts

    NARCIS (Netherlands)

    Miletic, Nemanja; Vukovic, Zorica; Nastasovic, Aleksandra; Loos, Katja; Miletić, Nemanja; Vuković, Zorica; Nastasović, Aleksandra

    2009-01-01

    Crosslinked macroporous hydrophilic poly(glycidyl methacrylate-co-ethylene glycol dimethacrylate)s [abbreviated poly(GMA-co-EGDMA)] with identical chemical structure (60% of glycidyl methacrylate) but with varied average pore sizes (from 30 to 560 nm), specific surface areas (from 13.2 to 106.0 m(2)

  10. Conjunction of Conducting Polymer Nanostructures with Macroporous Structured Graphene Thin Films for High-Performance Flexible Supercapacitors.

    Science.gov (United States)

    Memon, Mushtaque A; Bai, Wei; Sun, Jinhua; Imran, Muhammad; Phulpoto, Shah Nawaz; Yan, Shouke; Huang, Yong; Geng, Jianxin

    2016-05-11

    Fabrication of hybridized structures is an effective strategy to promote the performances of graphene-based composites for energy storage/conversion applications. In this work, macroporous structured graphene thin films (MGTFs) are fabricated on various substrates including flexible graphene papers (GPs) through an ice-crystal-induced phase separation process. The MGTFs prepared on GPs (MGTF@GPs) are recognized with remarkable features such as interconnected macroporous configuration, sufficient exfoliation of the conductive RGO sheets, and good mechanical flexibility. As such, the flexible MGTF@GPs are demonstrated as a versatile conductive platform for depositing conducting polymers (CPs), e.g., polyaniline (PAn), polypyrrole, and polythiophene, through in situ electropolymerization. The contents of the CPs in the composite films are readily controlled by varying the electropolymerization time. Notably, electrodeposition of PAn leads to the formation of nanostructures of PAn nanofibers on the walls of the macroporous structured RGO framework (PAn@MGTF@GPs): thereafter, the PAn@MGTF@GPs display a unique structural feature that combine the nanostructures of PAn nanofibers and the macroporous structures of RGO sheets. Being used as binder-free electrodes for flexible supercapacitors, the PAn@MGTF@GPs exhibit excellent electrochemical performance, in particular a high areal specific capacity (538 mF cm(-2)), high cycling stability, and remarkable capacitive stability to deformation, due to the unique electrode structures.

  11. Meso-Molding Three-Dimensional Macroporous Perovskites: A New Approach to Generate High-Performance Nanohybrid Catalysts

    DEFF Research Database (Denmark)

    Arandiyan, Hamidreza; Scott, Jason; Wang, Yuan

    2016-01-01

    Newly designed 3D highly ordered macro/mesoporous multifunctional La1-xCexCoO3 nanohybrid frameworks with a 2D hexagonal mesostructure were fabricated via facile meso-molding in a three-dimensionally macroporous perovskite (MTMP) route. The nanohybrid framework exhibited excellent catalytic...

  12. Meso-macroporous Al2O3 supported Ru catalysts for CO preferential oxidation in hydrogen-rich gases

    Institute of Scientific and Technical Information of China (English)

    Limiao Shen; Cheng Zhang; Yuan Liu

    2012-01-01

    Series of meso-macroporous Al2O3 supported Ru catalysts with different loadings were prepared by incipient wetness method and applied to preferential oxidation of CO in hydrogen-rich gases.N2 adsorption-desorption,SEM,XRD,TEM,CO chemisorption and H2-TPR techniques were employed to characterize the catalysts.The results indicate that Ru/Al2O3 catalysts have meso-macroporous structure,high surface area and high metal dispersion.The characterization results of XRD and CO chemisorption indicate the entry of Ru ions into Al2O3 lattice.The results of catalytic performance tests indicate that the meso-macroporous Al2O3 supported Ru catalysts for CO preferential oxidation showed good activity under high space velocity.It is proposed that the macropores in the Ru/Al2O3 catalyst favor mass transfer and mesopores help to improve the dispersion of metal,resulting in the excellent catalytic performance.

  13. Facile synthesis of a Cu-based MOF confined in macroporous carbon hybrid material with enhanced electrocatalytic ability.

    Science.gov (United States)

    Zhang, Yufan; Bo, Xiangjie; Luhana, Charles; Wang, Huan; Li, Mian; Guo, Liping

    2013-08-07

    The Cu-based MOF loaded on macroporous carbon (MPC) creates novel Cu-MOF-MPC hybrids for the first time. The obtained Cu-MOF-MPC composites are used as electrocatalysts for the oxidation of NADH and reduction of H2O2 in neutral solution.

  14. Cm-scale Heterogeneity in Degradation - Potential Impact on Leaching of MCPA through a Variably-Saturated Macroporous Clayey Till

    DEFF Research Database (Denmark)

    Rosenbom, Annette Elisabeth; Johnsen, Anders R.; Aamand, Jens;

    both flow and degradation are associated with macropores/wormholes. Results show that cm-scale heterogeneity in degradation potential with simple matrix flow has a negligible effect on MCPA leaching at one meter below soil surface. By introducing a wormhole in the low-permeable 3D-soil modeling domain...

  15. Macroporous poly(glycidyl methacrylate-co-ethylene glycol dimethacrylate) resins-Versatile immobilization supports for biocatalysts

    NARCIS (Netherlands)

    Miletic, Nemanja; Vukovic, Zorica; Nastasovic, Aleksandra; Loos, Katja; Miletić, Nemanja; Vuković, Zorica; Nastasović, Aleksandra

    Crosslinked macroporous hydrophilic poly(glycidyl methacrylate-co-ethylene glycol dimethacrylate)s [abbreviated poly(GMA-co-EGDMA)] with identical chemical structure (60% of glycidyl methacrylate) but with varied average pore sizes (from 30 to 560 nm), specific surface areas (from 13.2 to 106.0

  16. Prediction of biopore- and matrix-dominated flow from X-ray CT-derived macropore network characteristics

    Science.gov (United States)

    Naveed, Muhammad; Moldrup, Per; Schaap, Marcel G.; Tuller, Markus; Kulkarni, Ramaprasad; Vogel, Hans-Jörg; Wollesen de Jonge, Lis

    2016-10-01

    Prediction and modeling of localized flow processes in macropores is of crucial importance for sustaining both soil and water quality. However, currently there are no reliable means to predict preferential flow due to its inherently large spatial variability. The aim of this study was to investigate the predictive performance of previously developed empirical models for both water and air flow and to explore the potential applicability of X-ray computed tomography (CT)-derived macropore network characteristics. For this purpose, 65 cylindrical soil columns (6 cm diameter and 3.5 cm height) were extracted from the topsoil (5 cm to 8.5 cm depth) in a 15 m × 15 m grid from an agricultural field located in Silstrup, Denmark. All soil columns were scanned with an industrial X-ray CT scanner (129 µm resolution) and later employed for measurement of saturated hydraulic conductivity, air permeability at -30 and -100 cm matric potential, and gas diffusivity at -30 and -100 cm matric potential. Distribution maps for saturated hydraulic conductivity, air permeability, and gas diffusivity reflected no autocorrelation irrespective of soil texture and organic matter content. Existing empirical predictive models for saturated hydraulic conductivity and air permeability showed poor performance, as they were not able to realistically capture macropore flow. The tested empirical model for gas diffusivity predicted measurements at -100 cm matric potential reasonably well, but failed at -30 cm matric potential, particularly for soil columns with biopore-dominated flow. X-ray CT-derived macroporosity matched the measured air-filled porosity at -30 cm matric potential well. Many of the CT-derived macropore network characteristics were strongly interrelated. Most of the macropore network characteristics were also significantly correlated with saturated hydraulic conductivity, air permeability, and gas diffusivity. The predictive Ahuja et al. (1984) model for saturated hydraulic

  17. Random glycopeptide bead libraries for seromic biomarker discovery

    DEFF Research Database (Denmark)

    Kracun, Stjepan Kresimir; Cló, Emiliano; Clausen, Henrik

    2010-01-01

    Identification of disease-specific biomarkers is important to address early diagnosis and management of disease. Aberrant post-translational modifications (PTM) of proteins such as O-glycosylations (O-PTMs) are emerging as triggers of autoantibodies that can serve as sensitive biomarkers. Here we...... have developed a random glycopeptide bead library screening platform for detection of autoantibodies and other binding proteins. Libraries were build on biocompatible PEGA beads including a safety-catch C-terminal amide linker (SCAL) that allowed mild cleavage conditions (I(2)/NaBH(4) and TFA......) for release of glycopeptides and sequence determination by ESI-Orbitrap-MS(n). As proof-of-principle, tumor -specific glycopeptide reporter epitopes were built-in into the libraries and were detected by tumor-specific monoclonal antibodies and autoantibodies from cancer patients. Sequenced and identified...

  18. Methodological Study of Cell Separation with Domestic Immunomagnetic Beads

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    To establish the method of cell separation with domestic immuomagnetic beads, three methods were investigated. Direct method, SPA method and Biotin-Avidin method were applied to separate cell strain Hut-78 and CD4 positive cells. Separation rate of strain Hut-78 was more than 90 % in direct method. Detachment rate with papain was over 95 %. Cell activity was well retained. SPA method and Biotin-Avidin methods were also effective, but the direct method was superior to the other two techniques. Before separated by the direct method, CD4 positive cells constituted 46.4 %±6.4 % of mononuclear cells (MNC), but in eliminated suspension there was only 6.2 %±2.3 % CD4 positive cells left. In the separated part, 80.6 %±7.2 % of the cells combined with the beads. It is concluded that the direct method in separating cells had high sensitivity and specificity.

  19. Culture of soybean mesophyll protoplasts in alginate beads.

    Science.gov (United States)

    Tricoli, D M; Hein, M B; Carnes, M G

    1986-10-01

    Mesophyll protoplasts were isolated from leaves of 10 day old aseptically grown soybean seedlings, or from surface disinfested leaves of 3 week old plants grown in environmental chambers. The protoplasts were encapsulated in 2mm diameter Ca alginate beads. Immobilized protoplasts were induced to divide by culturing in shaker flasks containing an actively growing soybean cell suspension. The feeder cell suspension supported the division of protoplasts independent of the protoplast density in the Ca alginate beads. At day 18 after encapsulation, the alginate matrix was dissolved, releasing viable callus colonies. The feeder cell suspension obviated plating of protoplasts at high density which is usually required for subsequent cell division and colony development. Since the protoplasts were embedded at low density, the cell colonies were derived from single cells.

  20. TiO{sub 2} beads and TiO{sub 2}-chitosan beads for urease immobilization

    Energy Technology Data Exchange (ETDEWEB)

    Ispirli Doğaç, Yasemin, E-mail: yispirli@mu.edu.tr; Deveci, İlyas, E-mail: ideveci@mu.edu.tr; Teke, Mustafa, E-mail: mteke@mu.edu.tr; Mercimek, Bedrettin, E-mail: bedrettinmercimek@mu.edu.tr

    2014-09-01

    The aim of the present study is to synthesize TiO{sub 2} beads for urease immobilization. Two different strategies were used to immobilize the urease on TiO{sub 2} beads. In the first method (A), urease enzyme was immobilized onto TiO{sub 2} beads by adsorption and then crosslinking. In the second method (B), TiO{sub 2} beads were coated with chitosan-urease mixture. To determine optimum conditions of immobilization, different parameters were investigated. The parameters of optimization were initial enzyme concentration (0.5; 1; 1.5; 2 mg/ml), alginate concentration (1; 2; 3%), glutaraldehyde concentration (1; 2; 3% v/v) and chitosan concentration (2; 3; 4 mg/ml). The optimum enzyme concentrations were determined as 1.5 mg/ml for A and 1.0 mg/ml for B. The other optimum conditions were found 2.0% (w/v) for alginate concentration (both A and B); 3.0 mg/ml for chitosan concentration (B) and 2.0% (v/v) for glutaraldehyde concentration (A). The optimum temperature (20-60 °C), optimum pH (3.0-10.0), kinetic parameters, thermal stability (4–70 °C), pH stability (4.0-9.0), operational stability (0-230 min) and reusability (20 times) were investigated for characterization. The optimum temperatures were 30 °C (A), 40 °C (B) and 35 °C (soluble). The temperature profiles of the immobilized ureases were spread over a large area. The optimum pH values for the soluble urease and immobilized urease prepared by using methods (A) and (B) were found to be 7.5, 7.0, 7.0, respectively. The thermal stabilities of immobilized enzyme sets were studied and they maintained 50% activity at 65 °C. However, at this temperature free urease protected only 15% activity. - Highlights: • TiO{sub 2} and TiO{sub 2}-chitosan beads for urease immobilization have been prepared and characterized. • The beads used in this work are good matrices for the immobilization of urease. • The immobilized urease was shown to have good properties and stabilities (pH and thermal stability, operational

  1. A planar conducting microstructure to guide and confine magnetic beads to a sensing zone

    KAUST Repository

    Gooneratne, Chinthaka Pasan

    2011-08-01

    A novel planar conducting microstructure is proposed to transport and confine magnetic micro/nano beads to a sensing zone. Manipulation and concentration of magnetic beads are achieved by employing square-shaped conducting micro-loops, with a few hundred nano-meters in thickness, arranged in a unique fashion. These microstructures are designed to produce high magnetic field gradients which are directly proportional to the force applied to manipulate the magnetic beads. Furthermore, the size of the microstructures allows greater maneuverability and control of magnetic beads than what could be achieved by permanent magnets. The aim of the microstructures is to guide magnetic beads from a large area and confine them to a smaller area where for example quantification would take place. Experiments were performed with different concentrations of 2 μm diameter magnetic beads. Experimental results showed that magnetic beads could be successfully guided and confined to the sensing zone. © 2011 Elsevier B.V. All rights reserved.

  2. On the occurrence of ‘bead lightning’ phenomena in long laboratory sparks

    Energy Technology Data Exchange (ETDEWEB)

    Vayanganie, S.P.A., E-mail: amilavayanganie@gmail.com [Atmospheric Physics and Lightning Research Group, University of Colombo, Colombo 03 (Sri Lanka); Cooray, V.; Rahman, Mahbubur; Hettiarachchi, Pasan; Diaz, Oscar [Lightning Research Group, The Ångström Laboratory Division of Electricity, Department of Engineering Sciences, Uppsala University, Box 534, SE-751 21 Uppsala (Sweden); Fernando, M. [Atmospheric Physics and Lightning Research Group, University of Colombo, Colombo 03 (Sri Lanka)

    2016-02-22

    The formation of bead lightning, where the lightning channel appears to break up into luminous fragments, is still an object of speculation. Here we report similar observations in laboratory discharges. Analysis of time resolved photographs shows that the discharge channel exhibits a ‘bead pattern’ in the decaying stage of the discharge and the occurrence of loops in the channel sections where the bead pattern is observed. This result presents the first evidence that the rapid cooling of non-uniform channel sections could lead to the formation of beads. It is suggested that periodically occurring non-uniform channel sections could explain the bead pattern of lightning discharges. - Highlights: • For the first time, the occurrence of bead patterns in the channel of laboratory sparks was reported. • Depending on the geometry some regions of the channel decays faster than the other sections. • A possible mechanism for the occurrence of beads in decaying states of lightning flashes is proposed.

  3. Shape optimization and characterization of polysaccharide beads prepared by ionotropic gelation.

    Science.gov (United States)

    Smrdel, Polona; Bogataj, Marija; Zega, Anamarija; Planinsek, Odon; Mrhar, Ales

    2008-03-01

    The shape of drug loaded polysaccharide beads produced by ionotropic gelation has been optimized, with the aim of producing spherical beads suitable for further technological operations, such as coating. The optimization was performed on a model system sodium alginate/theophylline by inclusion of various fillers. Incorporation of excipients markedly influenced the morphological characteristics of the beads. The undesired irregular shape of beads caused by incorporation of the drug could only be improved by incorporating a combination of polycarbophil (PK) and polyvinylpyrrolidone (PVP). The spherical shape of these beads was stabilized mechanically by numerous air bubbles trapped inside the beads, which prevented the collapse of the beads during drying. The optimized method was shown to be applicable to a target system of pectin and an anti-inflammatory drug, LK-423.

  4. Brushite cement additives inhibit attachment to cell culture beads.

    Science.gov (United States)

    Jamshidi, Parastoo; Bridson, Rachel H; Wright, Adrian J; Grover, Liam M

    2013-05-01

    Brushite-forming calcium phosphate cements are of great interest as bone replacement materials because they are resorbable in physiological conditions. Cell-attached culture beads formed from this material could be of great use for cell therapy. Despite a significant amount of work on optimizing the physicochemical properties of these materials, there are very few studies that have evaluated the capacity of the materials to facilitate cell adhesion. In this study, we have formed resorbable calcium phosphate (brushite) culture beads and for the first time we showed that cell attachment to the surface of the brushite cement (BC) could be inhibited by the presence of an intermediate dicalcium phosphate-citrate complex, formed in the cement as a result of using citric acid, a retardant and viscosity modifier used in many cement formulations. The BC beads formed from the mixture of β-TCP/orthophosphoric acid using citric acid did not allow cell attachment without further treatment. Ageing of BC beads in serum-free Dulbecco's Modified Eagle's Medium (DMEM) solution at 37°C for 1 week greatly enhanced the cell adhesion capacity of the material. Scanning electron microscopy, X-ray diffraction (XRD), and confocal Raman microspectrometry indicated the increased capacity for cell adhesion was due to the changes in phase composition of BC. XRD patterns collected before and after ageing in aqueous solution and a high initial mass loss, suggest the formation of a dicalcium phosphate-citrate complex within the matrix. Since compacts formed from brushite powder supported cell attachment, it was hypothesized that the dicalcium phosphate-citrate complex prevented attachment to the cement surface.

  5. Selective manipulation of superparamagnetic beads by a magnetic microchip

    KAUST Repository

    Gooneratne, Chinthaka Pasan

    2013-07-01

    In this paper, a magnetic microchip (MMC) is presented, to first trap and then selectively manipulate individual, superparamagnetic beads (SPBs) to another trapping site. Trapping sites are realized through soft magnetic micro disks made of Ni80Fe20, and SPB motion is controlled by current-carrying, tapered, conducting lines made of Au. The MMC was realized using standard microfabrication techniques and provides a cheap and versatile platform for microfluidic systems for cell manipulation. © 2013 IEEE.

  6. Cellulose-Based Nanomaterials for Energy Applications.

    Science.gov (United States)

    Wang, Xudong; Yao, Chunhua; Wang, Fei; Li, Zhaodong

    2017-09-13

    Cellulose is the most abundant natural polymer on earth, providing a sustainable green resource that is renewable, degradable, biocompatible, and cost effective. Recently, nanocellulose-based mesoporous structures, flexible thin films, fibers, and networks are increasingly developed and used in photovoltaic devices, energy storage systems, mechanical energy harvesters, and catalysts components, showing tremendous materials science value and application potential in many energy-related fields. In this Review, the most recent advancements of processing, integration, and application of cellulose nanomaterials in the areas of solar energy harvesting, energy storage, and mechanical energy harvesting are reviewed. For solar energy harvesting, promising applications of cellulose-based nanostructures for both solar cells and photoelectrochemical electrodes development are reviewed, and their morphology-related merits are discussed. For energy storage, the discussion is primarily focused on the applications of cellulose-based nanomaterials in lithium-ion batteries, including electrodes (e.g., active materials, binders, and structural support), electrolytes, and separators. Applications of cellulose nanomaterials in supercapacitors are also reviewed briefly. For mechanical energy harvesting, the most recent technology evolution in cellulose-based triboelectric nanogenerators is reviewed, from fundamental property tuning to practical implementations. At last, the future research potential and opportunities of cellulose nanomaterials as a new energy material are discussed. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Cellulose nanofibrils aerogels generated from jute fibers.

    Science.gov (United States)

    Lin, Jinyou; Yu, Liangbo; Tian, Feng; Zhao, Nie; Li, Xiuhong; Bian, Fenggang; Wang, Jie

    2014-08-30

    In this work, we report the cellulose nanofibrils extracted from the pristine jute fibers via the pretreatments followed by the TEMPO (2,2,6,6-tetramethylpiperidine-1-oxyl radical)-mediated oxidation and mechanical disintegration. The effects of pretreatments by using the NaOH solution and dimethyl sulfoxide solvent on the fiber morphology and macro/micro-structures were investigated by polarizing microscope and synchrotron radiation wide/small-angle X-ray scattering (WAXS/SAXS). The cellulose nanofibrils exhibit a diameter ranging from 5 nm to 20 nm and a length of several micrometers, which have been assembled into cellulose aerogels by the lyophilization of as-prepared nanofibrils dispersions with various concentrations. The results indicated that the hierarchical structures of as-prepared cellulose aerogels were dependent on the dispersion concentrations. The WAXS results show that the typical cellulose aerogels are coexistence of cellulose I and cellulose II, which has a great promise for many potential applications, such as pharmaceutical, liquid filtration, catalysts, bio-nanocomposites, and tissue engineering scaffolds. Copyright © 2014 Elsevier Ltd. All rights reserved.

  8. Utilization of purified cellulose in fiber studies.

    Science.gov (United States)

    Penner, M H; Liaw, E T

    1990-01-01

    Purified cellulose-type fiber products are widely used in experimental nutrition. Their use in a broad spectrum of studies may potentially lead to the acceptance of the misconception that the various commercially available cellulose products are equivalent. In this paper we have attempted to show that this is not the case. The comparative structural data of Table 2 and the compositional data of Olsen et al provide examples which indicate that purified cellulose preparations should not necessarily be considered equivalent. Unfortunately, our current lack of understanding of how fibers are metabolized and how they may affect specific physiological parameters makes it difficult to determine which, if any, of the measurable structural and chemical properties will be of relevance for a given in vivo study. At present, it appears that researchers utilizing/evaluating the consequences of consuming a purified cellulose-type fiber would be prudent to provide at least a limited amount of data on the properties of the cellulose preparation used in their studies. The characterization of the cellulose product may be done by a variety of methods depending on the expertise of the laboratory. The methods and results discussed in this paper provide an example of the type of information which may be obtained from an in vitro characterization of cellulose products.

  9. Enhancement of Cellulose Degradation by Cattle Saliva.

    Science.gov (United States)

    Seki, Yasutaka; Kikuchi, Yukiko; Kimura, Yoshihiro; Yoshimoto, Ryo; Takahashi, Masatoshi; Aburai, Kenichi; Kanai, Yoshihiro; Ruike, Tatsushi; Iwabata, Kazuki; Sugawara, Fumio; Sakai, Hideki; Abe, Masahiko; Sakaguchi, Kengo

    2015-01-01

    Saccharification of cellulose is a promising technique for producing alternative source of energy. However, the efficiency of conversion of cellulose into soluble sugar using any currently available methodology is too low for industrial application. Many additives, such as surfactants, have been shown to enhance the efficiency of cellulose-to-sugar conversion. In this study, we have examined first whether cattle saliva, as an additive, would enhance the cellulase-catalyzed hydrolysis of cellulose, and subsequently elucidated the mechanism by which cattle saliva enhanced this conversion. Although cattle saliva, by itself, did not degrade cellulose, it enhanced the cellulase-catalyzed degradation of cellulose. Thus, the amount of reducing sugar produced increased approximately 2.9-fold by the addition of cattle saliva. We also found that non-enzymatic proteins, which were present in cattle saliva, were responsible for causing the enhancement effect. Third, the mechanism of cattle saliva mediated enhancement of cellulase activity was probably similar to that of the canonical surfactants. Cattle saliva is available in large amounts easily and cheaply, and it can be used without further purification. Thus, cattle saliva could be a promising additive for efficient saccharification of cellulose on an industrial scale.

  10. A novel cellulose hydrogel prepared from its ionic liquid solution

    Institute of Scientific and Technical Information of China (English)

    LI Lu; LIN ZhangBi; YANG Xiao; WAN ZhenZhen; CUI ShuXun

    2009-01-01

    A novel cellulose hydrogel is prepared by regenerating cellulose from its ionic liquid solution. The transparency cellulose hydrogel presents a good chemical stability and an acceptable mechanical property. This non-toxic cellulose hydrogel should be biocompatibie and may be useful in the future as a biomaterial.

  11. Model films of cellulose. I. Method development and initial results

    NARCIS (Netherlands)

    Gunnars, S.; Wågberg, L.; Cohen Stuart, M.A.

    2002-01-01

    This report presents a new method for the preparation of thin cellulose films. NMMO (N- methylmorpholine- N-oxide) was used to dissolve cellulose and addition of DMSO (dimethyl sulfoxide) was used to control viscosity of the cellulose solution. A thin layer of the cellulose solution is spin- coated

  12. Prevalence and trends of cellulosics in pharmaceutical dosage forms.

    Science.gov (United States)

    Mastropietro, David J; Omidian, Hossein

    2013-02-01

    Many studies have shown that cellulose derivatives (cellulosics) can provide various benefits when used in virtually all types of dosage forms. Nevertheless, the popularity of their use in approved drug products is rather unknown. This research reports the current prevalence and trends of use for 15 common cellulosics in prescription drug products. The cellulosics were powdered and microcrystalline cellulose (MCC), ethyl cellulose, hydroxypropyl cellulose (HPC), hydroxyethyl cellulose (HEC), hypromellose (HPMC), HPMC phthalate, HPMC acetate succinate, cellulose acetate (CA), CA phthalate, sodium (Na) and calcium (Ca) carboxymethylcellulose (CMC), croscarmellose sodium (XCMCNa), methyl cellulose, and low substituted HPC. The number of brand drug products utilizing each cellulosics was determined using the online drug index Rxlist. A total of 607 brand products were identified having one or more of the cellulosics as an active or inactive ingredient. An array of various dosage forms was identified and revealed HPMC and MCC to be the most utilized cellulosics in all products followed by XCMCNa and HPC. Many products contained two or more cellulosics in the formulation (42% containing two, 23% containing three, and 4% containing 4-5). The largest combination occurrence was HPMC with MCC. The use of certain cellulosics within different dosage form types was found to contain specific trends. All injectables utilized only CMCNa, and the same with all ophthalmic solutions utilizing HPMC, and otic suspensions utilizing HEC. Popularity and trends regarding cellulosics use may occur based on many factors including functionality, safety, availability, stability, and ease of manufacturing.

  13. Preparation of carboxymethyl cellulose produced from purun tikus (Eleocharis dulcis)

    Science.gov (United States)

    Sunardi, Febriani, Nina Mutia; Junaidi, Ahmad Budi

    2017-08-01

    Sodium carboxymethyl cellulose (Na-CMC) is one of the important modified cellulose, a water-soluble cellulose, which is widely used in many application of food, pharmaceuticals, detergent, paper coating, dispersing agent, and others. The main raw material of modified cellulose is cellulose from wood and cotton. Recently, much attention has been attracted to the use of various agriculture product and by-product, grass, and residual biomass as cellulose and modified cellulose source for addressing an environmental and economic concern. Eleocharis dulcis, commonly known as purun tikus (in Indonesia), is a native aquatic plant of swamp area (wetland) in Kalimantan, which consists of 30-40% cellulose. It is significantly considered as one of the alternative resources for cellulose. The aims of present study were to isolate cellulose from E. dulcis and then to synthesise Na-CMC from isolated cellulose. Preparation of carboxymethyl cellulose from E. dulcis was carried out by an alkalization and etherification process of isolated cellulose, using various concentration of sodium hydroxide (NaOH) and monochloroacetic acid (MCA). The results indicated that the optimum reaction of alkalization was reached at 20% NaOH and etherification at the mass fraction ratio of MCA to cellulose 1.0. The optimum reaction has the highest solubility and degree of substitution. The carboxymethylation process of cellulose was confirmed by Fourier Transform Infrared spectroscopy (FTIR). In addition, changes in crystallinity of cellulose and Na-CMC were evaluated by X-ray diffraction (XRD).

  14. Study for highly functional resin (macroporous resin) superior in removing micro particles in PWR primary circuit: on-site test

    Energy Technology Data Exchange (ETDEWEB)

    Itou, A.; Kondo, K.; Kouzuma, Y., E-mail: ayumu_itou@kyuden.co.jp [Kyusyu Electric Power Co., Inc., Minami-ku, Fukuoka (Japan); Umehara, R.; Shimizu, Y., E-mail: Ruyji_Umehara@mhi.co.jp [Mitsubishi Heavy Industries, Ltd., Hyogo-ku, Kobe (Japan); Kogawa, N.; Nagamine, K., E-mail: nkogawa@ndc.hq.mhi.co.jp [Nuclear Development Corp., Tokaimura, Ibaraki (Japan)

    2010-07-01

    In Japanese PWR plants, efforts to remove particulate constituents containing radioactive cobalt which provides a source of radiation exposure, are needed. Performance evaluation study was conducted for macroporous resin which was said to possess excellent performance in removing particulate constituents and whose practical accomplishment at plants in USA was reported to be good. As one of the means for radiation exposure reduction in PWR, a study for application of crud removing resin to actual plant was executed by laboratory experiments using simulated crud (Fe{sub 3}O{sub 4} particle). In this study, following two mechanisms were demonstrated as the particle capturing mechanism of macroporous resin; physical trapping by fine pores on resin surface; electrical adsorption onto resin surface. In addition, in parallel to the study for application of macroporous resin to actual PWR plant, on-site study was planned to investigate the primary system water chemistry during various stages of actual plant operation and to research performance of particle capturing in detail. As the on-site study, column experiments, there water was let pass through the column, were planned for various operation stage (startup period, power operation period and shutdown period). A kind of conventional gel-type resin and three kinds of macroporous resin were examined for onsite tests. As to particulate capturing, basic knowledge regarding capturing efficiency and influence of water chemistry on capturing performance were ordered. Capturing performance of each resin tested became clear and was ordered by comparison. Effectiveness of macroporous resin with regard to crud removal in primary coolant was confirmed. (author)

  15. Chitosan and chemically modified chitosan beads for acid dyes sorption

    Institute of Scientific and Technical Information of China (English)

    AZLAN Kamari; WAN SAIME Wan Ngah; LAI KEN Liew

    2009-01-01

    The capabilities of chitosan and chitosan-EGDE (ethylene glycol diglycidyl ether) beads for removing Acid Red 37 (AR 37) and Acid Blue 25 (AB 25) from aqueous solution were examined. Chitosan beads were cross-linked with EGDE to enhance its chemical resistance and mechanical strength. Experiments were performed as a function of pH, agitation period and concentration of AR 37 and AB 25. It was shown that the adsorption capacities of chitosan were comparatively higher than chitosan-EGDE for both acid dyes. This is mainly because cross-linking using EGDE reduces the major adsorption sites -NH3+ on chitosan. Langmuir isotherm model showed best conformity compared to Freundlich and BET. The kinetic experimental data agreed very well to the pseudo second-order kinetic model. The desorption study revealed that after three cycles of adsorption and desorption by NaOH and HCl, both adsorbents retained their promising adsorption abilities. FT-IR analysis proved that the adsorption of acid dyes onto chitosan-based adsorbents was a physical adsorption. Results also showed that chitosan and chitosan-EGDE beads were favourable adsorbers and could be employed as low-cost alternatives for the removal of acid dyes in wastewater treatment.

  16. HOM identification by bead pulling in the Brookhaven ERL cavity

    CERN Document Server

    Hahn, H; Jain, Puneet; Johnson, Elliott C; Xu, Wencan

    2014-01-01

    Exploratory measurements of the Brookhaven Energy Recovery Linac (ERL) cavity at superconducting temperature produced a long list of high order modes (HOMs). The niobium 5-cell cavity is terminated at each end with HOM ferrite dampers that successfully reduce the Q-factors to levels required to avoid beam break up (BBU) instabilities. However, a number of un-damped resonances with Q≥106 were found at 4 K and their mode identification forms the focus of this paper. The approach taken here consists of bead pulling on a copper (Cu) replica of the ERL cavity with dampers involving various network analyzer measurements. Several different S21 transmission measurements are used, including those taken from the fundamental input coupler to the pick-up probe across the cavity, others between beam-position monitor probes in the beam tubes, and also between probes placed into the cells. The bead pull technique suitable for HOM identification with a metallic needle or dielectric bead is detailed. This paper presents the...

  17. Buckling of open-section bead-stiffened composite panels

    Science.gov (United States)

    Laananen, D. H.; Renze, S. P.

    Stiffened panels are structures that can be designed to efficiently support inplane compression, bending, and shear loads. Although the stiffeners are usually discrete elements which are fastened or bonded to a flat or continuously curved plate, manufacturing methods such as thermoforming allow integral formation of the stiffeners in a panel. Such a configuration offers potential advantages in terms of a reduced number of parts and manufacturing operations. For thermoplastic composite panels stiffened by integrally formed open-section beads, the effects of bead spacing and bend cross-section geometry on the initiation of buckling under uniaxial compression and uniform shear loading were investigated. Finite elements results for a range of stiffened panel sizes and bead geometries are presented and compared with approximate closed-form solutions based on an effective flat plate size. Experimental verification of analytical predictions for one of the shear panels and one of the compression panels is described. Compensation of the forming tool to reduce the degree of initial curvature of the panels was found to be necessary.

  18. Liquid morphologies and capillary forces between three spherical beads

    Science.gov (United States)

    Semprebon, Ciro; Scheel, Mario; Herminghaus, Stephan; Seemann, Ralf; Brinkmann, Martin

    2016-07-01

    Equilibrium shapes of coalesced pendular bridges in a static assembly of spherical beads are computed by numerical minimization of the interfacial energy. Our present study focuses on generic bead configurations involving three beads, one of which is in contact to the two others while there is a gap of variable size between the latter. In agreement with previous experimental studies, we find interfacial "trimer" morphologies consisting of three coalesced pendular bridges, and "dimers" of two coalesced bridges. In a certain range of the gap opening we observe a bistability between the dimer and trimer morphology during changes of the liquid volume. The magnitude of the corresponding capillary forces in presence of a trimer or dimer depends, besides the gap opening, only on the volume or Laplace pressure of the liquid. For a given Laplace pressure, and for the same gap opening, the capillary forces induced by a trimer are only slightly larger than the corresponding forces in the presence of three pendular bridges. This observation is consistent with a plateau of capillary cohesion in terms of the saturation of a wetting liquid in the funicular regime, as reported in the experimental work [Scheel et al., Nat. Mater. 7, 189 (2008), 10.1038/nmat2117].

  19. Cellulosic ethanol: status and innovation

    Energy Technology Data Exchange (ETDEWEB)

    Lynd, L; Liang, Xiaoyu; Biddy, Mary; Allee, Andrew; Cai, Hao; Foust, Thomas; Himmel, Michael E.; Laser, Mark; Wang, Michael; Wyman, Charles

    2017-01-01

    Although the purchase price of cellulosic feedstocks is competitive with petroleum on an energy basis, the cost of lignocellulose conversion to ethanol using today’s technology is high. Cost reductions can be pursued via either in-paradigm or new-paradigm innovation. As an example of new-paradigm innovation, consolidated bioprocessing using thermophilic bacteria combined with milling during fermentation (cotreatment) is analyzed. Acknowledging the nascent state of this approach, our analysis indicates potential for radically improved cost competitiveness and feasibility at smaller scale compared to current technology, arising from (a) R&D-driven advances (consolidated bioprocessing with cotreatment in lieu of thermochemical pretreatment and added fungal cellulase), and (b) configurational changes (fuel pellet coproduction instead of electricity, gas boiler(s) in lieu of a solid fuel boiler).

  20. Surface modification of cellulose nanocrystals

    Institute of Scientific and Technical Information of China (English)

    WANG Neng; DING Enyong; CHENG Rongshi

    2007-01-01

    In order to improve the dispersibility of cellulose nanocrystal(CNC) particles,three difierent grafted reactions of acetylation,hydroxyethylation and hydroxypropylation were introduced to modify the CNC surface.The main advantages of these methods were the simple and easily controlled reaction conditions,and the dispersibility of the resulting products was distinctly improved.The properties of the modified CNC were characterized by means of Fourier transform infrared spectroscopy(FT-IR),13 C nuclear magnetic resonance(NMR),transmission electron microscopy(TEM)and thermogravimetric analyses(TGA).The results indicated mat after desiccation,the modification products could be dispersed again in the proper solvents by ultrasonic treatments,and the diameter of their particles had no obvious changes.However,their thermal degradation behaviors were quite different.The initial decomposition temperature of the modified products via hydroxyethylation or hydroxypropylation was lower than that of modified products via acetylation.

  1. Lyocell, The New Generation of Regenerated Cellulose

    Directory of Open Access Journals (Sweden)

    Éva Borbély

    2008-06-01

    Full Text Available For the majority of the last century, commercial routes to regenerated cellulosefibres have coped with the difficulties of making a good cellulose solution by using an easyto dissolve derivative (e.g. xanthane in the case of viscose rayon or complex (e.g.cuprammonium rayon. For the purposes of this paper, advanced cellulosic fibres aredefined as those made from a process involving direct dissolution of cellulose. The firstexamples of such fibres have now been generically designaed as lyocell fibres todistinguish them from rayons, and the first commercial lyocell fibre is Courtaulds’ Tencel.

  2. Cellulose-builder: a toolkit for building crystalline structures of cellulose.

    Science.gov (United States)

    Gomes, Thiago C F; Skaf, Munir S

    2012-05-30

    Cellulose-builder is a user-friendly program that builds crystalline structures of cellulose of different sizes and geometries. The program generates Cartesian coordinates for all atoms of the specified structure in the Protein Data Bank format, suitable for using as starting configurations in molecular dynamics simulations and other calculations. Crystalline structures of cellulose polymorphs Iα, Iβ, II, and III(I) of practically any size are readily constructed which includes parallelepipeds, plant cell wall cellulose elementary fibrils of any length, and monolayers. Periodic boundary conditions along the crystallographic directions are easily imposed. The program also generates atom connectivity file in PSF format, required by well-known simulation packages such as NAMD, CHARMM, and others. Cellulose-builder is based on the Bash programming language and should run on practically any Unix-like platform, demands very modest hardware, and is freely available for download from ftp://ftp.iqm.unicamp.br/pub/cellulose-builder.

  3. Oxidizing Cellulose to 2,3-Dialdehyde Cellulose by Sodium Periodate

    Institute of Scientific and Technical Information of China (English)

    MENG Shuxian; FENG Yaqing; LIANG Zupei; FU Qiang; ZHANG Enzhong

    2005-01-01

    Study on oxidizing cellulose to 2,3-dialdehyde cellulose by sodium periodate (NaIO4) was carried out. The effects of reaction conditions such as pH of solution, temperature, oxidant concentration, oxidation time, the particle size of 2,3-dialdehyde cellulose and alkali treatment temperature on the dialdehyde concentration of cellulose were investigated in detail. The results show that the aldehyde group content was created while reaction temperature and alkali treatment temperature increased.The most principal factors affecting the aldehyde group content of 2,3-dialdehyde cellulose were found out and the best oxidation conditions were as follows: the pH was 2, the reaction temperature was 45 ℃, the mass ratio of cellulose to NaIO4 was 1/2, the reaction time was 4 h, the alkali treatment temperature was 70 ℃ and smaller particle size was 0.80 mm.

  4. Brittle Culm1, a COBRA-like protein, functions in cellulose assembly through binding cellulose microfibrils.

    Science.gov (United States)

    Liu, Lifeng; Shang-Guan, Keke; Zhang, Baocai; Liu, Xiangling; Yan, Meixian; Zhang, Lanjun; Shi, Yanyun; Zhang, Mu; Qian, Qian; Li, Jiayang; Zhou, Yihua

    2013-01-01

    Cellulose represents the most abundant biopolymer in nature and has great economic importance. Cellulose chains pack laterally into crystalline forms, stacking into a complicated crystallographic structure. However, the mechanism of cellulose crystallization is poorly understood. Here, via functional characterization, we report that Brittle Culm1 (BC1), a COBRA-like protein in rice, modifies cellulose crystallinity. BC1 was demonstrated to be a glycosylphosphatidylinositol (GPI) anchored protein and can be released into cell walls by removal of the GPI anchor. BC1 possesses a carbohydrate-binding module (CBM) at its N-terminus. In vitro binding assays showed that this CBM interacts specifically with crystalline cellulose, and several aromatic residues in this domain are essential for binding. It was further demonstrated that cell wall-localized BC1 via the CBM and GPI anchor is one functional form of BC1. X-ray diffraction (XRD) assays revealed that mutations in BC1 and knockdown of BC1 expression decrease the crystallite width of cellulose; overexpression of BC1 and the CBM-mutated BC1s caused varied crystallinity with results that were consistent with the in vitro binding assay. Moreover, interaction between the CBM and cellulose microfibrils was largely repressed when the cell wall residues were pre-stained with two cellulose dyes. Treating wild-type and bc1 seedlings with the dyes resulted in insensitive root growth responses in bc1 plants. Combined with the evidence that BC1 and three secondary wall cellulose synthases (CESAs) function in different steps of cellulose production as revealed by genetic analysis, we conclude that BC1 modulates cellulose assembly by interacting with cellulose and affecting microfibril crystallinity.

  5. Brittle Culm1, a COBRA-like protein, functions in cellulose assembly through binding cellulose microfibrils.

    Directory of Open Access Journals (Sweden)

    Lifeng Liu

    Full Text Available Cellulose represents the most abundant biopolymer in nature and has great economic importance. Cellulose chains pack laterally into crystalline forms, stacking into a complicated crystallographic structure. However, the mechanism of cellulose crystallization is poorly understood. Here, via functional characterization, we report that Brittle Culm1 (BC1, a COBRA-like protein in rice, modifies cellulose crystallinity. BC1 was demonstrated to be a glycosylphosphatidylinositol (GPI anchored protein and can be released into cell walls by removal of the GPI anchor. BC1 possesses a carbohydrate-binding module (CBM at its N-terminus. In vitro binding assays showed that this CBM interacts specifically with crystalline cellulose, and several aromatic residues in this domain are essential for binding. It was further demonstrated that cell wall-localized BC1 via the CBM and GPI anchor is one functional form of BC1. X-ray diffraction (XRD assays revealed that mutations in BC1 and knockdown of BC1 expression decrease the crystallite width of cellulose; overexpression of BC1 and the CBM-mutated BC1s caused varied crystallinity with results that were consistent with the in vitro binding assay. Moreover, interaction between the CBM and cellulose microfibrils was largely repressed when the cell wall residues were pre-stained with two cellulose dyes. Treating wild-type and bc1 seedlings with the dyes resulted in insensitive root growth responses in bc1 plants. Combined with the evidence that BC1 and three secondary wall cellulose synthases (CESAs function in different steps of cellulose production as revealed by genetic analysis, we conclude that BC1 modulates cellulose assembly by interacting with cellulose and affecting microfibril crystallinity.

  6. BIOSYNTHESIS OF BACTERIAL CELLULOSE BY МEDUSOMYCES GISEVII

    OpenAIRE

    E. K. Gladysheva; E. A. Skiba

    2015-01-01

    Summary: Bacterial cellulose is an organic material that is synthesized by microorganisms extracellularly. Bacterial cellulose can be used in various industries. Especially, bacterial cellulose has found its application basically in medicine. The production of bacterial cellulose is a complicated and long process. The principal criterion for the process to be successful is bacterial cellulose to be obtained in a higher yield. Russia is lacking an operating facility to produce bacterial cellul...

  7. Hydrothermal synthesis of 2D ordered macroporous ZnO films

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The ZnO films with two-dimensional ordered macroporous structure were successfully fabricated through hydrothermal crystal growth of ZnO on the ZnO substrate covered with a mouolayer of polystyrene (PS) spheres as template.The precursor solution of hydrothermal crystal growth of ZnO were prepared by equitramine (HMT).The confinement effect of the PS spheres template on the growth of ZnO nanorods and the influence of sodium citrate on the crystal growth of ZnO had been studied.The film surface morphology and the preferential growth of ZnO crystal were investigated by scanning electron microscopy (SEM) and X-ray diffraction (XRD),respectively.Also,the photoluminescence spectrum of ZnO films had been measured,and the corresponding mechanism was discussed.

  8. Separation and purification of rebaudioside A from extract of Stevia Rebaudiana leaves by macroporous adsorption resins

    Directory of Open Access Journals (Sweden)

    Anvari Masoumeh

    2016-03-01

    Full Text Available The separation and purification of rebaudioside A from Stevia rebaudiana crude extracts (Steviosides by macroporous resin were optimized by Taguchi orthogonal array (OA experimental design methodology. This approach was applied to evaluate the influence of five factors (adsorption temperature, desorption time, elution solution ratio, adsorption volume and type of resin on the rebaudioside A yield. The percentage contribution of each factor was also determined. The results showed that elution solution ratio and adsorption volume made the greatest (59.6% and the lowest (1.3% contribution, respectively. The results showed that the Taguchi method is able to model the purification of rebaudioside A process well (R2 > 0.998 and can therefore be applied in future studies conducted in various fields. Adsorption temperature 35°C, desorption time 60min, elution solution ratio 3, adsorption volume 200ml and HPD-400 as resin were the best conditions determined by the Taguchi method.

  9. Noble metals binding on macroporous poly(GMA-co-EGDMA modified with ethylenediamine

    Directory of Open Access Journals (Sweden)

    ANTONIJE ONJIA

    2004-06-01

    Full Text Available Macroporous crosslinked poly(glycidyl methacrylate-co-ethylene glycol dimethacrylate, p(GME, was synthesized by suspension copolymerization and modified by reaction of the pendant epoxy groups with ethylenediamine. The sorption rate and capacity of the modified copolymer, p(GME-en for Rh(III, Au(III and Pt(IV ions were determined in batch experiments under non-competitive conditions. The uptake of Rh(III was faster than those of Au(III and Pt(IV. The sorption capacity for Pt(IV was determined in the pH range 0.9–6.0. The maximum Pt(IV uptake capacity onto p(GME-en at pH 5.5 was 1.30 mmol/g.

  10. Pore-filling Three-dimensionally Ordered Macroporous Polyimide Composite Proton Conducting Membranes

    Institute of Scientific and Technical Information of China (English)

    DAI Xin; GENG Lei; LIU Dan; L(U) Chang-li; YANG Bai

    2011-01-01

    The silica opal templates were prepared from three silica colloids of different diameters of 230 nm,500nm and 1.5 μm by a filtration route.The large-scale stable opal template membranes after sintering the deposited SiO2 opal template can be successfully obtained by optimizing the pH value and NaCl concentration in silica colloidal solutions.The three-dimensionally ordered macroporous(3DOM) polyimide membranes without crack were fabricated by reproducing the structure of silica opal template.We prepared the pore-filling composite proton exchange membranes by filling the 3DOM structure with proton conducting organosilane sol.The result indicates that the composite membranes exhibit higher water uptake than pure filling organosilane gel.The proton conductivity increased with the increasing of pore cell in composite membranes.

  11. Preparation and Properties of Macroporous Silicon Nitride Ceramics by Gelcasting and Carbonthermal Reaction

    Institute of Scientific and Technical Information of China (English)

    Wen ZHANG; Hongjie WANG; Zhihao JIN

    2005-01-01

    Macroporous silicon nitride (Si3N4) ceramics with high strength, uniform structure and relatively high porosity were obtained by gelcasting and carbonthermal reaction in a two-step sintering technique. Microstructure and composition were investigated by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction(XRD). Open porosity, pore size distribution and basic mechanical performance were measured by Archimedes method,mercury intrusion porosimetry and three-point bending methods, respectively. SEM and TEM results revealed that pores were formed by elongated β-Si3N4. SADP measurement proved the formation of SiC particles. The SiC granules were beneficial for the formation of high ratio elongated β-Si3N4, and at proper amount, they also acted as reinforcement phase. Thermodynamic analysis indicated that the mechanisms of the reactions were mainly associated with liquid-solid reaction and gas-liquid reaction.

  12. ADSORPTION OF TANNIN ACID ONTO AN AMINATED MACROPOROUS RESIN FROM AQUEOUS SOLUTIONS

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    A macroporous polymeric adsorbent NG-8 was synthesized with divinylbenzene using conventional suspension polymerization technique. Its aminated product NG-9 was prepared by introducing tertiary amino groups into NG-8 for removal of tannin acid from aqueous solutions. NG-9 could be used directly without a wetting process and had higher adsorption capacity than NG-8, which might be attributed to the enhanced adsorbent-adsorbate interaction due to the tertiary amino groups on the polymeric matrix. The Langmuir equation was successfully employed to describe the adsorption process. The adsorption enthalpy change further validated the uptake of tannin acid on NG-9 to be an enhanced physical adsorption because of the Lewis acid-base interaction. In addition, adsorption kinetic studies testified that the tertiary amino groups on the polymer matrix could decrease the adsorption rate maybe for the hindrance of the tertiary amino groups and water clusters built up.

  13. Visual and reversible carbon dioxide sensing enabled by doctor blade coated macroporous photonic crystals.

    Science.gov (United States)

    Lin, Yi-Han; Suen, Shing-Yi; Yang, Hongta

    2017-11-15

    With significant impacts of carbon dioxide on global climate change, carbon dioxide sensing is of great importance. However, most of the existing sensing technologies are prone to interferences from carbon monoxide, or suffer from the use of sophisticated instruments. This research reports the development of reproducible carbon dioxide sensor using roll-to-roll compatible doctor blade coated three-dimensional macroporous photonic crystals. The pores are functionalized with amine groups to allow the reaction with carbon dioxide in the presence of humidity. The adsorption of carbon dioxide leads to red-shift and amplitude reduction of the optical stop bands, resulting in carbon dioxide detection with visible readout. The dependences of the diffraction wavelength on carbon dioxide partial pressure for various amine-functionalized photonic crystals and different humidities in the environment are systematically investigated. In addition, the reproducibility of carbon dioxide sensing has also been demonstrated in this research. Copyright © 2017 Elsevier Inc. All rights reserved.

  14. ADSORPTION AND DESORPTION OF DSD ACID MANUFACTURING WASTEWATER ON MACROPOROUS RESIN

    Institute of Scientific and Technical Information of China (English)

    LONGChao; ZHANGQuanxing; 等

    2001-01-01

    4,4'-diaminostilbene-2,2'-disulfonic acid (DSD acid) manufacturing wastewater was treated by a macroporous resin in a fixed-bed column.The results showed that this method was suitable for removal of chemical oxygen demands(COD) and color,About 91% COD and 99.5% color removal were obtained under the optimum adsorption conditions.i.e.temperature 20℃,flow rate lbed volume/hour(BV/hr)and pH1-2.The resin was efficiently regenerated with aqueous sodium hydroxide and water.Furthermore,65.5% of 4,4'-dinitrostilbene-2,2'-disulfonic acid(DNS) could be recovered from wastewater for possible recycling to the manufactureing process.The adsorption capacity of resin remained constant during the repetition process of adsorption and desorption.

  15. Risk predicting of macropore flow using pedotransfer functions, textural maps and modeling

    DEFF Research Database (Denmark)

    Iversen, Bo Vangsø; Børgesen, Christen Duus; Lægdsmand, Mette;

    2011-01-01

    using combinations of different soil physical parameters. The neural network was able to develop reasonably accurate PTFs predicting log[k(−1)], whereas the prediction of log(Ks) was less accurate. Using the distributed data of the hydraulic properties derived from the PTFs, outputs of water flow...... of this study were first to develop pedotransfer functions (PTFs) predicting near-saturated [k(−1)] and saturated (Ks) hydraulic conductivity using simple soil parameters as predictors and second to use this information and a newly developed rasterbased soil property map of Denmark to identify risk areas...... for macropore flow. The data set was based on hydraulic measurements on large, undisturbed soil columns from different localities in Denmark. Unsaturated [k(h)] and saturated hydraulic conductivity were measured in the laboratory; k(−1) representing the hydraulic conductivity of the soil matrix...

  16. Adsorption of Monobutyl Phthalate from Aqueous Phase onto Two Macroporous Anion-Exchange Resins

    Directory of Open Access Journals (Sweden)

    Zhengwen Xu

    2014-01-01

    Full Text Available As new emerging pollutants, phthalic acid monoesters (PAMs pose potential ecological and human health risks. In the present study, adsorption performance of monobutyl phthalate (MBP onto two macroporous base anion-exchange resins (D-201 and D-301 was discussed. It was found that the adsorption isotherms were best fitted by the Langmuir equation while the adsorption kinetics were well described by pseudo-first-order model. Analyses of sorption isotherms and thermodynamics proved that the adsorption mechanisms for DBP onto D-201 were ion exchange. However, the obtained enthalpy values indicate that the sorption process of MBP onto D-301 is physical adsorption. The equilibrium adsorption capacities and adsorption rates of DBP on two different resins increased with the increasing temperature of the solution. D-301 exhibited a higher adsorption capacity of MBP than D-201. These results proved that D-301, as an effective sorbent, can be used to remove phthalic acid monoesters from aqueous solution.

  17. Extraction of anthocyanins from black bean canning wastewater with macroporous resins.

    Science.gov (United States)

    Wang, Xiaoxi; Hansen, Conly; Allen, Karin

    2014-02-01

    This study investigated purification of anthocyanins from black bean canning wastewater by column chromatography with 5 types of macroporous resins (Diaion Hp20, Sepabeads Sp70, Sepabeads Sp207, Sepabeads Sp700, and Sepabeads Sp710). By-product of canned black beans was partially purified by filtration, in anticipation of higher performance during column chromatography. Equilibrium adsorption isotherms were measured and analyzed using Langmuir and Freundlich isotherm models. Both Langmuir (all R² ≥ 0.98) and Freundlich (all R² ≥ 0.97) models can describe the adsorption process of anthocyanins from black bean canning wastewater using the tested resins. The adsorption and desorption behaviors of anthocyanins were studied using a dynamic method on the 5 types of resins, and Sp700 presented the highest adsorption capacity (39 ± 4 mg/g; P canning wastewater.

  18. Formation of photoluminescent n-type macroporous silicon: Effect of magnetic field and lateral electric potential

    Energy Technology Data Exchange (ETDEWEB)

    Antunez, E.E. [Centro de Investigación en Ingeniería y Ciencias Aplicadas, UAEM, Av. Universidad 1001, Col. Chamilpa, Cuernavaca, Morelos, CP 62210 (Mexico); Estevez, J.O. [Instituto de Física, B. Universidad Autónoma de Puebla, A.P. J-48, Puebla 72570 (Mexico); Campos, J. [Instituto de Energías Renovables, UNAM, Priv. Xochicalco S/N, Temixco, Morelos, CP 62580 (Mexico); Basurto-Pensado, M.A. [Centro de Investigación en Ingeniería y Ciencias Aplicadas, UAEM, Av. Universidad 1001, Col. Chamilpa, Cuernavaca, Morelos, CP 62210 (Mexico); Agarwal, V., E-mail: vagarwal@uaem.mx [Centro de Investigación en Ingeniería y Ciencias Aplicadas, UAEM, Av. Universidad 1001, Col. Chamilpa, Cuernavaca, Morelos, CP 62210 (Mexico)

    2014-11-15

    Metal electrode-free electrochemical etching of low doped n-type silicon substrates, under the combined effect of magnetic and lateral electric field, is used to fabricate photoluminescent n-type porous silicon structures in dark conditions. A lateral gradient in terms of structural characteristics (i.e. thickness and pore dimensions) along the electric field direction is formed. Enhancement of electric and magnetic field resulted in the increase of pore density and a change in the shape of the macropore structure, from circular to square morphology. Broad photoluminescence (PL) emission from 500 to 800 nm, with a PL peak wavelength ranging from 571 to 642 nm, is attributed to the wide range of microporous features present on the porous silicon layer.

  19. ADSORPTION AND DESORPTION OF DSD ACID MANUFACTURING WASTEWATER ON MACROPOROUS RESIN

    Institute of Scientific and Technical Information of China (English)

    LONG Chao; ZHANG Quanxing; XU Zhaoyi; CHEN Jinlong; LI Aimin; CHENG Zhiqiang

    2001-01-01

    4,4'-diaminostilbene-2, 2'-disulfonic acid (DSD acid) manufacturing wastewater was treated by a macroporous resin in a fixed-bed column. The results showed that this method was suitable for removal of chemical oxygen demands (COD) and color About 91% COD and 99.5% color removal were obtained under the optimum adsorption conditions, i.e. temperature 20 ℃, flow rate 1 bed volume/hour (BV/hr) and pH1-2. The resin was efficiently regenerated with aqueous sodium hydroxide and water. Furthermore, 65.5% of 4, 4 '-dinitrostilbene-2, 2 '-disulfonic acid (DNS) could be recovered from wastewater for possible recycling to the manufacturing process. The adsorption capacity of resin remained constant during the repetition process of adsorption and desorption.

  20. Universal approach for selective trace metal determinations via sequential injection-bead injection-lab-on-valve using renewable hydrophobic bead surfaces as reagent carriers

    DEFF Research Database (Denmark)

    Long, Xiangbao; Miró, Manuel; Hansen, Elo Harald

    2005-01-01

    involves the use of poly(styrene-divinylbenzene) beads containing pendant octadecyl moieties (C18-PS/DVB), which are preimpregnated with a selective organic metal chelating agent prior to the automatic manipulation of the beads in the microbore conduits of the LOV unit. By adapting this approach...

  1. Optimizing Extraction of Cellulose and Synthesizing Pharmaceutical Grade Carboxymethyl Sago Cellulose from Malaysian Sago Pulp

    National Research Council Canada - National Science Library

    Veeramachineni, Anand; Sathasivam, Thenapakiam; Muniyandy, Saravanan; Janarthanan, Pushpamalar; Langford, Steven; Yan, Lim

    2016-01-01

    .... This work focuses on using sago biomass to obtain cellulose as the raw material, through chemical processing using acid hydrolysis, alkaline extraction, chlorination and bleaching, finally converting...

  2. Fabrication of polyaniline/carboxymethyl cellulose/cellulose nanofibrous mats and their biosensing application

    Energy Technology Data Exchange (ETDEWEB)

    Fu, Jiapeng, E-mail: firgexiao@sina.cn; Pang, Zengyuan, E-mail: pangzengyuan1212@163.com; Yang, Jie, E-mail: young1993@126.com; Huang, Fenglin, E-mail: flhuang@jiangnan.edu.cn; Cai, Yibing, E-mail: yibingcai@jiangnan.edu.cn; Wei, Qufu, E-mail: qfwei@jiangnan.edu.cn

    2015-09-15

    Graphical abstract: - Highlights: • PANI nanorods have been grown onto the surface of CMC/cellulose nanofibers for the fabrication of biosensor substrate material. • The proposed laccase biosensor exhibited a low detection limit and high sensitivity in the detection of catechol. • Hierarchical PANI/CMC/cellulose nanofibers are the promising material in the design of high-efficient biosensors. - Abstract: We report a facile approach to synthesizing and immobilizing polyaniline nanorods onto carboxymethyl cellulose (CMC)-modified cellulose nanofibers for their biosensing application. Firstly, the hierarchical PANI/CMC/cellulose nanofibers were fabricated by in situ polymerization of aniline on the CMC-modified cellulose nanofiber. Subsequently, the PANI/CMC/cellulose nanofibrous mat modified with laccase (Lac) was used as biosensor substrate material for the detection of catechol. PANI/CMC/cellulose nanofibers with highly conductive and three dimensional nanostructure were characterized by scanning electron microscopy (SEM), transmission electron microscope (TEM), Fourier transform infrared spectra (FT-IR), cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). Under optimum conditions, the Lac/PANI/CMC/cellulose/glassy carbon electrode (GCE) exhibited a fast response time (within 8 s), a linear response range from 0.497 μM to 2.27 mM with a high sensitivity and low detection limit of 0.374 μM (3σ). The developed biosensor also displayed good repeatability, reproducibility as well as selectivity. The results indicated that the composite mat has potential application in enzyme biosensors.

  3. Pre-irradiation grafting of cellulose and slightly carboxymethylated cellulose (CMC) fibres

    Energy Technology Data Exchange (ETDEWEB)

    Benke, N. [Institute of Isotopes, HAS, Budapest (Hungary); Takacs, E. [Institute of Isotopes, HAS, Budapest (Hungary)]. E-mail: takacs@iki.kfki.hu; Wojnarovits, L. [Institute of Isotopes, HAS, Budapest (Hungary); Borsa, J. [Budapest University of Technology and Economics, Budapest (Hungary)

    2007-08-15

    Acrylamide, hydroxypropyl acrylate, hydroxypropyl methacrylate and 2-ethylhexyl methacrylate vinyl monomers were grafted onto cellulose as well as onto cellulose of improved accessibility (slightly carboxymethylated cellulose (CMC)) by the pre-irradiation grafting technique. The effect of dose, monomer structure, crosslinking agent and carboxymethylation on the grafting yield was studied and the optimal conditions for the grafting were established. Grafting, with the exception of acrylamide (AAm), decreased the swelling of the samples, which is advantageous for some applications. In case of AAm decrease in swelling was observed only when crosslinking agent was applied. At low doses (<5 kGy) the high accessibility of carboxymethylated cellulose resulted in a higher grafting yield.

  4. Optimizing Extraction of Cellulose and Synthesizing Pharmaceutical Grade Carboxymethyl Sago Cellulose from Malaysian Sago Pulp

    Directory of Open Access Journals (Sweden)

    Anand Kumar Veeramachineni

    2016-06-01

    Full Text Available Sago biomass is an agro-industrial waste produced in large quantities, mainly in the Asia-Pacific region and in particular South-East Asia. This work focuses on using sago biomass to obtain cellulose as the raw material, through chemical processing using acid hydrolysis, alkaline extraction, chlorination and bleaching, finally converting the material to pharmaceutical grade carboxymethyl sago cellulose (CMSC by carboxymethylation. The cellulose was evaluated using Thermogravimetric Analysis (TGA, Infrared Spectroscopy (FTIR, X-Ray Diffraction (XRD, Differential Scanning Calorimetry (DSC and Field Emission Scanning Electronic Microscopy (FESEM. The extracted cellulose was analyzed for cellulose composition, and subsequently modified to CMSC with a degree of substitution (DS 0.6 by typical carboxymethylation reactions. X-ray diffraction analysis indicated that the crystallinity of the sago cellulose was reduced after carboxymethylation. FTIR and NMR studies indicate that the hydroxyl groups of the cellulose fibers were etherified through carboxymethylation to produce CMSC. Further characterization of the cellulose and CMSC were performed using FESEM and DSC. The purity of CMSC was analyzed according to the American Society for Testing and Materials (ASTM International standards. In this case, acid and alkaline treatments coupled with high-pressure defibrillation were found to be effective in depolymerization and defibrillation of the cellulose fibers. The synthesized CMSC also shows no toxicity in the cell line studies and could be exploited as a pharmaceutical excipient.

  5. Immobilized Kluyveromyces marxianus cells in carboxymethyl cellulose for production of ethanol from cheese whey: experimental and kinetic studies.

    Science.gov (United States)

    Roohina, Fatemeh; Mohammadi, Maedeh; Najafpour, Ghasem D

    2016-09-01

    Cheese whey fermentation to ethanol using immobilized Kluyveromyces marxianus cells was investigated in batch and continuous operation. In batch fermentation, the yeast cells were immobilized in carboxymethyl cellulose (CMC) polymer and also synthesized graft copolymer of CMC with N-vinyl-2-pyrrolidone, denoted as CMC-g-PVP, and the efficiency of the two developed cell entrapped beads for lactose fermentation to ethanol was examined. The yeast cells immobilized in CMC-g-PVP performed slightly better than CMC with ethanol production yields of 0.52 and 0.49 g ethanol/g lactose, respectively. The effect of supplementation of cheese whey with lactose (42, 70, 100 and 150 g/l) on fermentative performance of K. marxianus immobilized in CMC beads was considered and the results were used for kinetic studies. The first order reaction model was suitable to describe the kinetics of substrate utilization and modified Gompertz model was quite successful to predict the ethanol production. For continuous ethanol fermentation, a packed-bed immobilized cell reactor (ICR) was operated at several hydraulic retention times; HRTs of 11, 15 and 30 h. At the HRT of 30 h, the ethanol production yield using CMC beads was 0.49 g/g which implies that 91.07 % of the theoretical yield was achieved.

  6. Effect of tillage on macropore flow and phosphorus transport to tile drains

    Science.gov (United States)

    Williams, Mark R.; King, Kevin W.; Ford, William; Buda, Anthony R.; Kennedy, Casey D.

    2016-04-01

    Elevated phosphorus (P) concentrations in subsurface drainage water are thought to be the result of P bypassing the soil matrix via macropore flow. The objectives of this study were to quantify event water delivery to tile drains via macropore flow paths during storm events and to determine the effect of tillage practices on event water and P delivery to tiles. Tile discharge, total dissolved P (DP) and total P (TP) concentrations, and stable oxygen and deuterium isotopic signatures were measured from two adjacent tile-drained fields in Ohio, USA during seven spring storms. Fertilizer was surface-applied to both fields and disk tillage was used to incorporate the fertilizer on one field while the other remained in no-till. Median DP concentration in tile discharge prior to fertilizer application was 0.08 mg L-1 in both fields. Following fertilizer application, median DP concentration was significantly greater in the no-tilled field (1.19 mg L-1) compared to the tilled field (0.66 mg L-1), with concentrations remaining significantly greater in the no-till field for the remainder of the monitored storms. Both DP and TP concentrations in the no-till field were significantly related to event water contributions to tile discharge, while only TP concentration was significantly related to event water in the tilled field. Event water accounted for between 26 and 69% of total tile discharge from both fields, but tillage substantially reduced maximum contributions of event water. Collectively, these results suggest that incorporating surface-applied fertilizers has the potential to substantially reduce the risk of P transport from tile-drained fields.

  7. A macroporous bioreactor super activated by the recombinant human transforming growth factor-beta 3

    Directory of Open Access Journals (Sweden)

    Ugo eRipamonti

    2012-06-01

    Full Text Available Macroporous single-phase hydroxyapatite (HA and biphasic HA/β-tricalcium phosphate with 33% post-sinter hydroxyapatite (HA/β-TCP were combined with 25 or 125 µg recombinant human transforming growth factor-β3 (hTGF-β3 to engineer a super activated bioreactor implanted in orthotopic calvarial and heterotopic rectus abdominis muscle sites and harvested on day 30 and 90. Coral-derived calcium carbonate fully converted (100% and partially converted to 5% and 13% hydroxyapatite/calcium carbonate (HA/CC preloaded with 125 and 250 µg hTGF-β3, and 1:5 and 5:1 binary applications of hTGF-β3: hOP-1 by weight, were implanted in the rectus abdominis and harvested on day 20 and 30, respectively, to monitor spatial/temporal morphogenesis by high doses of hTGF-β3. Bone formation was assessed on decalcified paraffin-embedded sections by measuring the fractional volume of newly-formed bone. On day 30 and 90, single phase HA implants showed greater amounts of bone when compared to biphasic specimens; 5 % and 13 % HA/CC pre-loaded with 125 and 250 µg hTGF-β3 showed substantial induction of bone formation; 250 µg hTGF-β3 induced as yet unreported massive induction of bone formation as early as 20 days prominently outside the profile of the macroporous constructs. The induction of bone formation is controlled by the implanted ratio of the recombinant morphogens, i.e. the 1:5 hTGF-β3:hOP-1 ratio by weight was greater than the inverse ratio. The unprecedented tissue induction by single doses of 250 µg hTGF-β3 resulting in rapid bone morphogenesis of vast mineralized ossicles with multiple trabeculations surfaced by contiguous secreting osteoblasts is the novel molecular and morphological frontier for the induction of bone formation in clinical contexts.

  8. Delta-sleep inducing peptide entrapment in the charged macroporous matrices

    Energy Technology Data Exchange (ETDEWEB)

    Sukhanova, Tatiana V., E-mail: sukhanovat@mail.ru [Shemyakin and Ovchinnikov Institute of Bioorganic Chemistry, Laboratory of Cell Interactions, Miklukho-Maklaya st., 16/10 Moscow (Russian Federation); Artyukhov, Alexander A.; Gurevich, Yakov M.; Semenikhina, Marina A. [Mendeleyev University of Chemical Technology of Russia, Research and Teaching Center “Biomaterials”, Miusskaya sq., 9 Moscow (Russian Federation); Prudchenko, Igor A. [Shemyakin and Ovchinnikov Institute of Bioorganic Chemistry, Laboratory of Peptide Chemistry, Miklukho-Maklaya st., 16/10 Moscow (Russian Federation); Shtilman, Mikhail I. [Mendeleyev University of Chemical Technology of Russia, Research and Teaching Center “Biomaterials”, Miusskaya sq., 9 Moscow (Russian Federation); Markvicheva, Elena A. [Shemyakin and Ovchinnikov Institute of Bioorganic Chemistry, Laboratory Polymers for Biology, Miklukho-Maklaya st., 16/10 Moscow (Russian Federation)

    2014-09-01

    Various biomolecules, for example proteins, peptides etc., entrapped in polymer matrices, impact interactions between matrix and cells, including stimulation of cell adhesion and proliferation. Delta-sleep inducing peptide (DSIP) possesses numerous beneficial properties, including its abilities in burn treatment and neuronal protection. DSIP entrapment in two macroporous polymer matrices based on copolymer of dimethylaminoethyl methacrylate and methylen-bis-acrylamide (Co-DMAEMA-MBAA) and copolymer of acrylic acid and methylen-bis-acrylamide (Co-AA-MBAA) has been studied. Quite 100% of DSIP has been entrapped into positively charged Co-DMAEMA-MBAA matrix, while the quantity of DSIP adsorbed on negatively charged Co-AA-MBAA was only 2–6%. DSIP release from Co-DMAEMA-MBAA was observed in saline solutions (0.9% NaCl and PBS) while there was no DSIP release in water or 25% ethanol, thus ionic strength was a reason of this process. - Graphical abstract: Delta-sleep inducing peptide possessing neuroprotective and wound healing properties was adsorbed on positively charged polymer matrix Co-DMAEMA-MBAA for tissue engineering. The peptide released from Co-DMAEMA-MBAA matrix in function of ionic strength of solution, pH decreasing stimulated peptide release from Co-DMAEMA-MBAA matrix for 3 h. This construction could be a base of new bioactive implants. - Highlights: • Macroporous positively charged Co-DMAEMA-MBAA matrix pore size was 20–35 μm. • DSIP was adsorbed on Co-DMAEMA-MBAA totally in 16 h. • Its release depends on ionic strength of solution (no release in 25% ethanol or water). • Co-DMAEMA-MBAA matrix swelling depends on pH and ionic strength of solution. • DSIP is destroyed in PBS and 0.9% NaCl in 5 days, but in water it was more stable.

  9. NMR imaging of fluid exchange between macropores and matrix in eogenetic karst

    Science.gov (United States)

    Florea, L.J.; Cunningham, K.J.; Altobelli, S.

    2009-01-01

    Sequential time-step images acquired using nuclear magnetic resonance (NMR) show the displacement of deuterated water (D2O) by fresh water within two limestone samples characterized by a porous and permeable limestone matrix of peloids and ooids. These samples were selected because they have a macropore system representative of some parts of the eogenetic karst limestone of the Biscayne Aquifer in southeastern Florida. The macroporosity, created by the trace fossil Ophiomorpha, is principally well connected and of centimeter scale. These macropores occur in broadly continuous stratiform zones that create preferential flow layers within the hydrogeologic units of the Biscayne. This arrangement of porosity is important because in coastal areas, it could produce a preferential pathway for salt water intrusion. Two experiments were conducted in which samples saturated with D2O were placed in acrylic chambers filled with fresh water and examined with NMR. Results reveal a substantial flux of fresh water into the matrix porosity with a simultaneous loss of D 2O. Specifically, we measured rates upward of 0.001 mL/h/g of sample in static conditions, and perhaps as great as 0.07 mL/h/g of sample when fresh water continuously flows past a sample at velocities less than those found within stressed areas of the Biscayne. These experiments illustrate how fresh water and D2O, with different chemical properties, migrate within one type of matrix porosity found in the Biscayne. Furthermore, these experiments are a comparative exercise in the displacement of sea water by fresh water in the matrix of a coastal, karst aquifer since D2O has a greater density than fresh water. ?? 2008 National Ground Water Association.

  10. Hierarchically oriented macroporous anode-supported solid oxide fuel cell with thin ceria electrolyte film.

    Science.gov (United States)

    Chen, Yu; Zhang, Yanxiang; Baker, Jeffrey; Majumdar, Prasun; Yang, Zhibin; Han, Minfang; Chen, Fanglin

    2014-04-09

    Application of anode-supported solid oxide fuel cell (SOFC) with ceria based electrolyte has often been limited by high cost of electrolyte film fabrication and high electrode polarization. In this study, dense Gd0.1Ce0.9O2 (GDC) thin film electrolytes have been fabricated on hierarchically oriented macroporous NiO-GDC anodes by a combination of freeze-drying tape-casting of the NiO-GDC anode, drop-coating GDC slurry on NiO-GDC anode, and co-firing the electrolyte/anode bilayers. Using 3D X-ray microscopy and subsequent analysis, it has been determined that the NiO-GDC anode substrates have a porosity of around 42% and channel size from around 10 μm at the electrolyte side to around 20 μm at the other side of the NiO-GDC (away from the electrolyte), indicating a hierarchically oriented macroporous NiO-GDC microstructure. Such NiO-GDC microstructure shows a tortuosity factor of ∼1.3 along the thickness direction, expecting to facilitate gas diffusion in the anode during fuel cell operation. SOFCs with such Ni-GDC anode, GDC film (30 μm) electrolyte, and La0.6Sr0.4Co0.2Fe0.8O3-GDC (LSCF-GDC) cathode show significantly enhanced cell power output of 1.021 W cm(-2) at 600 °C using H2 as fuel and ambient air as oxidant. Electrochemical Impedance Spectroscopy (EIS) analysis indicates a decrease in both activation and concentration polarizations. This study has demonstrated that freeze-drying tape-casting is a very promising approach to fabricate hierarchically oriented porous substrate for SOFC and other applications.

  11. Rhombohedral iron trifluoride with a hierarchized macroporous/mesoporous texture from gaseous fluorination of iron disilicide

    Energy Technology Data Exchange (ETDEWEB)

    Guérin, Katia, E-mail: katia.araujo_da_silva@univ-bpclermont.fr [Université Clermont Auvergne, Université Blaise Pascal, Institut de Chimie de Clermont-Ferrand, BP 10448, F-63000 Clermont-Ferrand (France); CNRS, UMR 6296, ICCF, F-63171 Aubière (France); Delbègue, Diane; Louvain, Nicolas; Doubtsof, Léa; Hamwi, André [Université Clermont Auvergne, Université Blaise Pascal, Institut de Chimie de Clermont-Ferrand, BP 10448, F-63000 Clermont-Ferrand (France); CNRS, UMR 6296, ICCF, F-63171 Aubière (France); Laik, Barbara; Pereira-Ramos, Jean-Pierre [Université Paris Est Créteil, Institut de Chimie et des Matériaux Paris-Est, UMR CNRS 7182, Thiais (France); Tahar-sougrati, Moulay; Jumas, Jean-Claude [Université Montpellier II, Institut Charles Gerhardt de Montpellier, UMR CNRS 5253, Montpellier (France); Willmann, Patrick; Cénac-Morthe, Céline [Centre National d' Etudes Spatiales, Toulouse (France)

    2016-04-15

    Stable low temperature rhombohedral iron trifluoride has been obtained by the fluorination under the pure fluorine gas of iron disilicide. The combination of both unusual fluorination process and precursor avoids to get unhydrated crystalline FeF{sub 3} particles and allows the formation of hierarchized channels of mesoporous/macroporous texture favorable for lithium diffusion. The fluorination mechanism proceeds by temperature steps from the formation, for a fluorination temperature below 200 °C, of an amorphous phase and an intermediate iron difluoride identified mainly by {sup 57}Fe Mössbauer spectroscopy before getting, as soon as a fluorination temperature of 260 °C is reached, the rhombohedral FeF{sub 3}. Both amorphous and crystallized samples display good ability for electrochemical process when used as cathode in lithium-ion battery. The low diameter of rhombohedral structure channels is balanced by an appropriate mesoporous texture and a capacity of 225 mAh.g{sup −1} after 5 cycles for a discharge cut-off of 2.5 V vs. Li{sup +}/Li at a current density of C/20 has been obtained and stabilized at 95 mAh.g{sup −1} after 116 cycles. - Highlights: • We investigated the synthesis of rhombohedral FeF{sub 3} by solid–gas reaction from iron disilicide. • We demonstrated that depending on the fluorination temperature various phases are stabilized. • We got a hierarchized macroporous/mesoporous texture. • We studied the electrochemical performances of amorphous and crystallized FeF{sub 3}. • Crystallized FeF{sub 3} presents a high faradic yield at first cycle focusing on insertion process.

  12. Surface functionalization of macroporous polymeric materials by treatment with air low temperature plasma.

    Science.gov (United States)

    Molina, R; Sole, I; Vílchez, A; Bertran, E; Solans, C; Esquena, J

    2013-04-01

    Polystyrene/divinylbenzene (PS-DVB) macroporous monoliths obtained using highly concentrated emulsions as templates show a superhydrophobic behaviour, restricting their potential technological applications, especially those related to adhesion and wetting. Air plasma treatments were carried out in order to modulate wetting properties, modifying the surface chemical composition of macroporous polystyrene/divinylbenzene materials. The superhydrophobic behaviour was rapidly suppressed by air plasma treatment, greatly reducing the water contact angle, from approximately 150 degrees to approximately 90 degrees, in only 10 seconds of treatment. The new surface chemical groups, promoted by plasma active species, were characterized by surface analysis techniques with different depth penetration specificity (contact angle, XPS, FTIR and SEM). Results demonstrated that very short treatment times produced different chemical functionalities, mainly C-O, C=O, O-C=O and C-N, which provide the materials with predominantly acidic surface properties. However, plasma active species did not penetrate deeply through the interconnected pores of the material. FTIR analysis evidenced that the new hydrophilic surface groups promoted by plasma active species are in a negligibly concentration compared to bulk chemical groups, and are located in a very thin surface region on the PS-DVB monolith surface (significantly below 2 microm). XPS analysis of treated monoliths revealed a progressive increase of oxygen and nitrogen content as a function of plasma treatment time. However, oxidation of the PS-DVB monoliths surface prevails over the incorporation of nitrogen atoms. Finally, SEM studies indicated that the morphology of the plasma treated PS-DVB does not significantly change even for the longest air plasma treatment time studied (120 s).

  13. Silicon microtubes made by immersing macroporous silicon into ammonium fluoride solution

    Energy Technology Data Exchange (ETDEWEB)

    Huanca, Danilo Roque, E-mail: droqueh@usp.br [Laboratorio de sensores e Dispositivos do Instituto de Física e Química da Universidade Federal de Itajubá, Avenida BPS, 1303, CEP 37500 903 Itajubá, MG (Brazil); Laboratório de Microeletrônica da Escola Politécnica da USP, Avenida Prof. Luciano Gualberto, travessa 3 n° 380, CEP 05508-900 São Paulo, SP (Brazil); Kim, Hae Yong [Laboratório de Processamento de Sinais da Escola Politécnica da USP, Avenida Prof. Luciano Gualberto, travessa 3 n° 380, CEP 05508-900 São Paulo, SP (Brazil); Salcedo, Walter Jaimes [Laboratório de Microeletrônica da Escola Politécnica da USP, Avenida Prof. Luciano Gualberto, travessa 3 n° 380, CEP 05508-900 São Paulo, SP (Brazil)

    2015-06-15

    In this paper, we report the fabrication of silicon microtubes (SMT) by electrochemical dissolution of macroporous silicon layers immersed into aqueous solution of NH{sub 4}F mixed with Na{sub 2}SO{sub 4}, at different pH levels (4.5–9.5). Well-defined SMT have been obtained at pH 6.5, 7.5 and 9.5, whereas for other pH levels, the surface of the porous structure becomes passivated or formation of needle-like structure occurs. The mean inner diameter and the thickness of walls of the tubes shown to be depended on the pH level of the solutions. In this investigation, we obtained silicon tubes with inner diameter from 0.2 to 2.0 μm with thickness wall from about 0.23 to 0.50 μm. The investigation of these structures indicates that for tube formation the pH level and predominance of the anisotropic dissolution are necessary conditions. The tube formation cannot be explained regarding the silicon dissolution mechanism. For this aim, the role of the space charge region must be regarded. The structural characterization of silicon tubes was achieved by X-ray diffraction (XRD), X-ray energy dispersive Spectroscopy (EDS) and Raman spectroscopy and the results pointed out that these tubes are constituted by crystalline silicon structures covered by a very thin silicon oxide film. In this paper, the formation mechanism of the SMT is also discussed, highlighting the role of the space charge region (SCR) and the pH level for tube formation. - Highlights: • We fabricate silicon microtubes using macroporous silicon as a starting material. • Depending on the pH level, well-defined tubes are formed or the surface is passivate. • It was identified that the key factors for tube formation are the pH level and the space charge region.

  14. Fate and transport of selected estrogen compounds in Hawaii soils: Effect of soil type and macropores

    Science.gov (United States)

    D'Alessio, Matteo; Vasudevan, Dharni; Lichwa, Joseph; Mohanty, Sanjay K.; Ray, Chittaranjan

    2014-10-01

    The fate and transport of estrogen compounds in the environment is of increasing concern due to their potential impact on freshwater organisms, ecosystems and human health. The behavior of these compounds in batch experiments suggests low mobility, while field studies indicate the persistence of estrogen compounds in the soil with the possibility of migration to surface water as well as groundwater. To better understand the movement of these chemicals through soils, we examined their transport in three different Hawaiian soils and two aqueous matrices. The three different soils used were an Oxisol, a Mollisol and a cinder, characterized by different mineralogical properties and collected at depths of 60-90 cm and 210-240 cm. Two liquid matrices were used; deionized (DI) water containing calcium chloride (CaCl2), and recycled water collected from a wastewater treatment facility. The experiments were conducted in packed and structured columns. Non-equilibrium conditions were observed during the study, especially in the structured soil. This is believed to be primarily related to the presence of macropores in the soil. The presence of macropores resulted in reduced contact time between soil and estrogens, which facilitated their transport. We found that the organic carbon content and mineralogical composition of the soils had a profound effect on the transport of the estrogens. The mobility of estrone (E1) and 17β-estradiol (E2) was greater in cinder than in the other soils. In column experiments with recycled water, earlier breakthrough peaks and longer tails of estrogens were produced compared to those observed using DI water. The use of recycled water for agricultural purposes and the siting of septic tanks and cesspools should be critically reviewed in light of these findings, especially in areas where groundwater is the primary source of potable water, such as Hawaii.

  15. Fate and transport of selected estrogen compounds in Hawaii soils: effect of soil type and macropores.

    Science.gov (United States)

    D'Alessio, Matteo; Vasudevan, Dharni; Lichwa, Joseph; Mohanty, Sanjay K; Ray, Chittaranjan

    2014-10-01

    The fate and transport of estrogen compounds in the environment is of increasing concern due to their potential impact on freshwater organisms, ecosystems and human health. The behavior of these compounds in batch experiments suggests low mobility, while field studies indicate the persistence of estrogen compounds in the soil with the possibility of migration to surface water as well as groundwater. To better understand the movement of these chemicals through soils, we examined their transport in three different Hawaiian soils and two aqueous matrices. The three different soils used were an Oxisol, a Mollisol and a cinder, characterized by different mineralogical properties and collected at depths of 60-90 cm and 210-240 cm. Two liquid matrices were used; deionized (DI) water containing calcium chloride (CaCl2), and recycled water collected from a wastewater treatment facility. The experiments were conducted in packed and structured columns. Non-equilibrium conditions were observed during the study, especially in the structured soil. This is believed to be primarily related to the presence of macropores in the soil. The presence of macropores resulted in reduced contact time between soil and estrogens, which facilitated their transport. We found that the organic carbon content and mineralogical composition of the soils had a profound effect on the transport of the estrogens. The mobility of estrone (E1) and 17β-estradiol (E2) was greater in cinder than in the other soils. In column experiments with recycled water, earlier breakthrough peaks and longer tails of estrogens were produced compared to those observed using DI water. The use of recycled water for agricultural purposes and the siting of septic tanks and cesspools should be critically reviewed in light of these findings, especially in areas where groundwater is the primary source of potable water, such as Hawaii.

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

    Science.gov (United States)

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

    2017-05-01

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

  17. Regenerated cellulose-silk fibroin blends fibers.

    Science.gov (United States)

    Marsano, Enrico; Corsini, Paola; Canetti, Maurizio; Freddi, Giuliano

    2008-08-15

    Fibers made of cellulose and silk fibroin at different composition were wet spun from solutions by using N-methylmorpholine N-oxide hydrates (NMMO/H(2)O) as solvent and ethanol as coagulant. Different spinning conditions were used. The fibers were characterized by different techniques: FTIR-Raman, scanning electron microscopy, wide-angle x-ray diffraction, DSC analysis. The results evidence a phase separation in the whole blends compositions. The tensile characterization, however, illustrates that the properties of the blends fibers are higher respect to a linear behaviour between the pure polymers, confirming a good compatibility between cellulose and silk fibroin. The fibers containing 75% of cellulose show better mechanical properties than pure cellulose fibers: modulus of about 23 GPa and strength to break of 307 MPa.

  18. Carboxymethylation of Cellulose by Microwave irradiation

    Institute of Scientific and Technical Information of China (English)

    YE; Jun

    2001-01-01

    Cellulose may be readily converted into ethers involving primary and secondary alcohol groups in each monomer unit and the glycosidic bonds. However, these reactions are rather more complicated than with simple substances, because the stereochemistry of the cellulose molecule is such that the vast majority of its hydroxyl groups form intra-chain hydrogen bonds or inter-chain hydrogen bonds with contiguous molecules. Carboxymethylcellulose (CMC) has played an important part in the commercial uses of cellulose derivatives. CMC becomes alkali and water soluble. The polarity can, in fact, be increased by introduction of ionizing groups, ie carboxymethyl group. CMC is generally produced by the reaction of alkali cellulose with chloroacetic acid.……

  19. Reactive Liftoff of Crystalline Cellulose Particles

    Science.gov (United States)

    Teixeira, Andrew R.; Krumm, Christoph; Vinter, Katherine P.; Paulsen, Alex D.; Zhu, Cheng; Maduskar, Saurabh; Joseph, Kristeen E.; Greco, Katharine; Stelatto, Michael; Davis, Eric; Vincent, Brendon; Hermann, Richard; Suszynski, Wieslaw; Schmidt, Lanny D.; Fan, Wei; Rothstein, Jonathan P.; Dauenhauer, Paul J.

    2015-06-01

    The condition of heat transfer to lignocellulosic biomass particles during thermal processing at high temperature (>400 °C) dramatically alters the yield and quality of renewable energy and fuels. In this work, crystalline cellulose particles were discovered to lift off heated surfaces by high speed photography similar to the Leidenfrost effect in hot, volatile liquids. Order of magnitude variation in heat transfer rates and cellulose particle lifetimes was observed as intermediate liquid cellulose droplets transitioned from low temperature wetting (500-600 °C) to fully de-wetted, skittering droplets on polished surfaces (>700 °C). Introduction of macroporosity to the heated surface was shown to completely inhibit the cellulose Leidenfrost effect, providing a tunable design parameter to control particle heat transfer rates in industrial biomass reactors.

  20. Dissolution enthalpies of cellulose in ionic liquids.

    Science.gov (United States)

    Parviainen, Helena; Parviainen, Arno; Virtanen, Tommi; Kilpeläinen, Ilkka; Ahvenainen, Patrik; Serimaa, Ritva; Grönqvist, Stina; Maloney, Thaddeus; Maunu, Sirkka Liisa

    2014-11-26

    In this work, interactions between cellulose and ionic liquids were studied calorimetrically and by optical microscopy. Two novel ionic liquids (1,5-Diazabicyclo[4.3.0]non-5-enium propionate and N-methyl-1,5-diazabicyclo[4.3.0]non-5-enium dimethyl phosphate) and 1-ethyl-3-methylimidazolium acetate-water mixtures were used as solvents. Optical microscopy served in finding the extent of dissolution and identifying the dissolution pattern of the cellulose sample. Calorimetric studies identified a peak relating to dissolution of cellulose in solvent. The transition did, however, not indicate complete dissolution, but rather dissolution inside fibre or fibrils. This method was used to study differences between four cellulose samples with different pretreatment or origins.

  1. Reactive Liftoff of Crystalline Cellulose Particles.

    Science.gov (United States)

    Teixeira, Andrew R; Krumm, Christoph; Vinter, Katherine P; Paulsen, Alex D; Zhu, Cheng; Maduskar, Saurabh; Joseph, Kristeen E; Greco, Katharine; Stelatto, Michael; Davis, Eric; Vincent, Brendon; Hermann, Richard; Suszynski, Wieslaw; Schmidt, Lanny D; Fan, Wei; Rothstein, Jonathan P; Dauenhauer, Paul J

    2015-06-09

    The condition of heat transfer to lignocellulosic biomass particles during thermal processing at high temperature (>400 °C) dramatically alters the yield and quality of renewable energy and fuels. In this work, crystalline cellulose particles were discovered to lift off heated surfaces by high speed photography similar to the Leidenfrost effect in hot, volatile liquids. Order of magnitude variation in heat transfer rates and cellulose particle lifetimes was observed as intermediate liquid cellulose droplets transitioned from low temperature wetting (500-600 °C) to fully de-wetted, skittering droplets on polished surfaces (>700 °C). Introduction of macroporosity to the heated surface was shown to completely inhibit the cellulose Leidenfrost effect, providing a tunable design parameter to control particle heat transfer rates in industrial biomass reactors.

  2. Efficient cellulose solvent: quaternary ammonium chlorides.

    Science.gov (United States)

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

    2013-10-01

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

  3. Structural and morphological characterization of cellulose pulp

    CSIR Research Space (South Africa)

    Ocwelwang, A

    2015-09-01

    Full Text Available Understanding the structure of cellulose is of utmost importance in order to enhance its accessibility and reactivity to chemical processing. Therefore, the aim of this study was to evaluate the effect of ultrasound pretreatment on the structure...

  4. The Sequence of Appearance of Bead Sets at the Filippovka I Burial in the Southern Urals

    Directory of Open Access Journals (Sweden)

    Anikeeva Olga Viktorovna

    2015-06-01

    Full Text Available The differences in the composition of bead sets from the Filippovka I burial were analyzed by the author in order to determine regularities in their co-occurrence. The mineralogical analysis has revealed the glass beads made of olivine and fluorite. The mineralogical and technological study allowed to classify all beads according to manufacturing techniques. On the basis of the comparison with beads of the same age from India, Persia, Middle Asia, Northern Black Sea coast, the Caucasus, and the Pamir, possible production centers have been hypothesized. The results were compared with earlier published data on bead sets from the Southern Urals burials of the late 6th - early 3rd centuries B.C. The literature data on the timing of appearance and the origin of beads analogous to those from Filippovka barrows were also analyzed. The results suggest that the observed differences in the composition of bead sets reflect the appearance or disappearance of particular bead types in the region. The analysis of mutual occurrence of certain bead types allowed to allocate two groups of the sets which are smoothly replacing each other in time. This allowed the author to reconstruct the sequence of appearance of bead sets in the Filippovka I burial.

  5. Preparation and characterization of chitosan/cashew gum beads loaded with Lippia sidoides essential oil

    Energy Technology Data Exchange (ETDEWEB)

    Paula, Haroldo C.B., E-mail: hpaula@ufc.br [Department of Analytical and Physical Chemistry, Federal University of Ceara, UFC, Fortaleza-CE (Brazil); Sombra, Fernanda Matoso; Cavalcante, Rafaela de Freitas; Abreu, Flavia O.M.S. [Department of Analytical and Physical Chemistry, Federal University of Ceara, UFC, Fortaleza-CE (Brazil); Paula, Regina C.M. de [Department of Organic and Inorganic Chemistry, Federal University of Ceara, UFC, Fortaleza-CE (Brazil)

    2011-03-12

    Beads based on chitosan (CH) and cashew gum (CG), were prepared and loaded with an essential oil with larvicide activity (Lippia sidoides - Ls). CH and CH-CG beads were characterized by scanning electron microscopy (SEM), infrared and UV-VIS spectroscopy, thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC), as well as, regarding their larvicide loading, swelling, in vitro and in vivo release kinetics. The oil encapsulation was evidenced by FTIR analysis and LS loading ranges from 2.4% to 4.4%. CH beads duly showed swelling degree (Q) values from 4.0 to 6.7, reaching equilibrium after 30 min, whereas crosslinked CH-CG beads showed lower swelling values, from 0.4 to 3.8, exhibiting a longer equilibrium time. Liquid transport parameters have revealed diffusion coefficient for CH-CG beads, as low as 2 x 10{sup -15} m{sup 2}/s. TGA and DSC revealed that CH:CG crosslinked beads are more thermally stable than CH beads. In vitro release follows a non-Fickian diffusion profile for both bead types, however, and a prolonged release being achieved only after beads crosslinking. In vivo release showed that both CH and CH-CG presented a prolonged larvicide effect. These aforesaid results, indicate that CH-CG beads loaded with LS are efficient for A. aegypti larval control.

  6. Echicetin coated polystyrene beads: a novel tool to investigate GPIb-specific platelet activation and aggregation.

    Science.gov (United States)

    Navdaev, Alexey; Subramanian, Hariharan; Petunin, Alexey; Clemetson, Kenneth J; Gambaryan, Stepan; Walter, Ulrich

    2014-01-01

    von Willebrand factor/ristocetin (vWF/R) induces GPIb-dependent platelet agglutination and activation of αIIbβ3 integrin, which also binds vWF. These conditions make it difficult to investigate GPIb-specific signaling pathways in washed platelets. Here, we investigated the specific mechanisms of GPIb signaling using echicetin-coated polystyrene beads, which specifically activate GPIb. We compared platelet activation induced by echicetin beads to vWF/R. Human platelets were stimulated with polystyrene beads coated with increasing amounts of echicetin and platelet activation by echicetin beads was then investigated to reveal GPIb specific signaling. Echicetin beads induced αIIbβ3-dependent aggregation of washed platelets, while under the same conditions vWF/R treatment led only to αIIbβ3-independent platelet agglutination. The average distance between the echicetin molecules on the polystyrene beads must be less than 7 nm for full platelet activation, while the total amount of echicetin used for activation is not critical. Echicetin beads induced strong phosphorylation of several proteins including p38, ERK and PKB. Synergistic signaling via P2Y12 and thromboxane receptor through secreted ADP and TxA2, respectively, were important for echicetin bead triggered platelet activation. Activation of PKG by the NO/sGC/cGMP pathway inhibited echicetin bead-induced platelet aggregation. Echicetin-coated beads are powerful and reliable tools to study signaling in human platelets activated solely via GPIb and GPIb-triggered pathways.

  7. Dose-response curve of a microfluidic magnetic bead-based surface coverage sandwich assay.

    Science.gov (United States)

    Cornaglia, Matteo; Trouillon, Raphaël; Tekin, H Cumhur; Lehnert, Thomas; Gijs, Martin A M

    2015-09-25

    Magnetic micro- and nanoparticles ('magnetic beads') have been used to advantage in many microfluidic devices for sensitive antigen (Ag) detection. Today, assays that use as read-out of the signal the number count of immobilized beads on a surface for quantification of a sample's analyte concentration have been among the most sensitive and have allowed protein detection lower than the fgmL(-1) concentration range. Recently, we have proposed in this category a magnetic bead surface coverage assay (Tekin et al., 2013 [1]), in which 'large' (2.8μm) antibody (Ab)-functionalized magnetic beads captured their Ag from a serum and these Ag-carrying beads were subsequently exposed to a surface pattern of fixed 'small' (1.0μm) Ab-coated magnetic beads. When the system was exposed to a magnetic induction field, the magnet dipole attractive interactions between the two bead types were used as a handle to approach both bead surfaces and assist with Ag-Ab immunocomplex formation, while unspecific binding (in absence of an Ag) of a large bead was reduced by exploiting viscous drag flow. The dose-response curve of this type of assay had two remarkable features: (i) its ability to detect an output signal (i.e. bead number count) for very low Ag concentrations, and (ii) an output signal of the assay that was non-linear with respect to Ag concentration. We explain here the observed dose-response curves and show that the type of interactions and the concept of our assay are in favour of detecting the lowest analyte concentrations (where typically either zero or one Ag is carried per large bead), while higher concentrations are less efficiently detected. We propose a random walk process for the Ag-carrying bead over the magnetic landscape of small beads and this model description explains the enhanced overall capture probability of this assay and its particular non-linear dose response curves.

  8. Comparison of four supports for adsorption of reactive dyes by immobilized Aspergillus fumigatus beads

    Institute of Scientific and Technical Information of China (English)

    WANG Bao-e; HU Yong-you

    2007-01-01

    Four materials, sodium carboxymethylcellulose (Na-CMC), sodium alginate (SA), polyvinyl alcohol (PVA), and chitosan (CTS), were prepared as supports for entrapping fungus Aspergillus fumigatus. The adsorption of synthetic dyes, reactive brilliant blue KN-R, and reactive brilliant red K-2BP, by these immobilized gel beads and plain gel beads was evaluated. The adsorption efficiencies of reactive brilliant red K-2BP and reactive brilliant blue KN-R by CTS immobilized beads were 89.1% and 93.5% in 12 h, respectively. The adsorption efficiency by Na-CMC immobilized beads was slightly lower than that of mycelial pellets. But the dye culture mediums were almost completely decolorized in 48 h using the above-mentioned two immobilized beads (exceeding 95%). The adsorption efficiency by SA immobilized beads exceeded 92% in 48 h. PVA-SA immobilized beads showed the lowest adsorption efficiency, which was 79.8% for reactive brilliant red K-2BP and 92.5% for reactive brilliant blue KN-R in 48 h. Comparing the adsorption efficiency by plain gel beads, Na-CMC plain gel beads ranked next to CTS ones. SA and PVA-SA plain gel beads hardly had the ability of adsorbing dyes. Subsequently, the growth of mycelia in Na-CMC and SA immobilized beads were evaluated. The biomass increased continuously in 72 h. The adsorption capacity of reactive brilliant red K-2BP and reactive brilliant blue KN-R by Na-CMC immobilized beads was 78.0 and 86.7 mg/g, respectively. The SEM micrographs show that the surface structure of Na-CMC immobilized bead is loose and finely porous, which facilitates diffusion of the dyes.

  9. Use of cellulose-containing wastes

    Energy Technology Data Exchange (ETDEWEB)

    Erzinkyan, L.A.; Akhinyan, R.M.; Petrosyan, L.G.; Ngoyan, R.G.

    1981-01-01

    Cellulose containing wastes from various industries were hydrolyzed by different microorganisms to glucose. Penicillium, Aspergillus, Mucor, Fusarium, and Bacterium cellaseum were the most effective organisms, catalyzing complete degradation of cellulose. The hydrolysis product (glucose) promoted the growth of various yeasts: Torulopsis pinus, Candida solani, C. guilliermondii, and C. pelliculosa. The yeast biomass yield reached 60.5% and was rich in protein, vitamins, and minerals.

  10. Cellulose-water interaction: a spectroscopic study

    OpenAIRE

    Lindh, Erik L

    2016-01-01

    The human society of today has a significantly negative impact on the environment and needs to change its way of living towards a more sustainable path if to continue to live on a healthy planet. One path is believed to be an increased usage of naturally degradable and renewable raw materials and, therefore, attention has been focused on the highly abundant biopolymer cellulose. However, a large drawback with cellulose-based materials is the significant change of their mechanical properties w...

  11. Isolation of cellulose microfibrils - An enzymatic approach

    Directory of Open Access Journals (Sweden)

    Sain, M.

    2006-11-01

    Full Text Available Isolation methods and applications of cellulose microfibrils are expanding rapidly due to environmental benefits and specific strength properties, especially in bio-composite science. In this research, we have success-fully developed and explored a novel bio-pretreatment for wood fibre that can substantially improve the microfibril yield, in comparison to current techniques used to isolate cellulose microfibrils. Microfibrils currently are isolated in the laboratory through a combination of high shear refining and cryocrushing. A high energy requirement of these procedures is hampering momentum in the direction of microfibril isolation on a sufficiently large scale to suit potential applications. Any attempt to loosen up the microfibrils by either complete or partial destruction of the hydrogen bonds before the mechanical process would be a step forward in the quest for economical isolation of cellulose microfibrils. Bleached kraft pulp was treated with OS1, a fungus isolated from Dutch Elm trees infected with Dutch elm disease, under different treatment conditions. The percentage yield of cellulose microfibrils, based on their diameter, showed a significant shift towards a lower diameter range after the high shear refining, compared to the yield of cellulose microfibrils from untreated fibres. The overall yield of cellulose microfibrils from the treated fibres did not show any sizeable decrease.

  12. Utilization of biocatalysts in cellulose waste minimization

    Energy Technology Data Exchange (ETDEWEB)

    Woodward, J.; Evans, B.R.

    1996-09-01

    Cellulose, a polymer of glucose, is the principal component of biomass and, therefore, a major source of waste that is either buried or burned. Examples of biomass waste include agricultural crop residues, forestry products, and municipal wastes. Recycling of this waste is important for energy conservation as well as waste minimization and there is some probability that in the future biomass could become a major energy source and replace fossil fuels that are currently used for fuels and chemicals production. It has been estimated that in the United States, between 100-450 million dry tons of agricultural waste are produced annually, approximately 6 million dry tons of animal waste, and of the 190 million tons of municipal solid waste (MSW) generated annually, approximately two-thirds is cellulosic in nature and over one-third is paper waste. Interestingly, more than 70% of MSW is landfilled or burned, however landfill space is becoming increasingly scarce. On a smaller scale, important cellulosic products such as cellulose acetate also present waste problems; an estimated 43 thousand tons of cellulose ester waste are generated annually in the United States. Biocatalysts could be used in cellulose waste minimization and this chapter describes their characteristics and potential in bioconversion and bioremediation processes.

  13. Biohydrogen, bioelectricity and bioalcohols from cellulosic materials

    Energy Technology Data Exchange (ETDEWEB)

    Nissila, M.

    2013-03-01

    The demand for renewable energy is increasing due to increasing energy demand and global warming associated with increasing use of fossil fuels. Renewable energy can be derived from biological production of energy carriers from cellulosic biomass. These biochemical processes include biomass fermentation to hydrogen, methane and alcohols, and bioelectricity production in microbial fuel cells (MFCs). The objective of this study was to investigate the production of different energy carriers (hydrogen, methane, ethanol, butanol, bioelectricity) through biochemical processes. Hydrogen production potential of a hot spring enrichment culture from different sugars was determined, and hydrogen was produced continuously from xylose. Cellulolytic and hydrogenic cultures were enriched on cellulose, cellulosic pulp materials, and on silage at different process conditions. The enrichment cultures were further characterized. The effect of acid pretreatment on hydrogen production from pulp materials was studied and compared to direct pulp fermentation to hydrogen. Electricity and alcohol(s) were simultaneously produced from xylose in MFCs and the exoelectrogenic and alcohologenic enrichment cultures were characterized. In the end, the energy yields obtained from different biochemical processes were determined and compared. In this study, cultures carrying out simultaneous cellulose hydrolysis and hydrogen fermentation were enriched from different sources at different operational conditions. These cultures were successfully utilized for cellulose to hydrogen fermentation in batch systems. Based on these results further research should be conducted on continuous hydrogen production from cellulosic materials.

  14. Wannier-Stark electro-optical effect, quasi-guided and photonic modes in 2D macroporous silicon structures with SiO2 coatings

    Science.gov (United States)

    Karachevtseva, L.; Goltviansky, Yu.; Sapelnikova, O.; Lytvynenko, O.; Stronska, O.; Bo, Wang; Kartel, M.

    2016-12-01

    Opportunities to enhance the properties of structured surfaces were demonstrated on 2D macroporous silicon structures with SiO2 coatings. We investigated the IR light absorption oscillations in macroporous silicon structures with SiO2 coatings 0-800 nm thick. The Wannier-Stark electro-optical effect due to strong electric field on Si-SiO2boundary and an additional electric field of quasi-guided optical modes were taken into account. The photonic modes and band gaps were also considered as peculiarities in absorbance spectra of macroporous silicon structures with a thick SiO2 coating. The photonic modes do not coincide with the quasi-guided modes in the silicon matrix and do not appear in absorption spectra of 2D macroporous silicon structures with surface nanocrystals.

  15. Purification of Houttuynia cordata Thunb. Essential Oil Using Macroporous Resin Followed by Microemulsion Encapsulation to Improve Its Safety and Antiviral Activity

    National Research Council Canada - National Science Library

    Pang, Jianmei; Dong, Wujun; Li, Yuhuan; Xia, Xuejun; Liu, Zhihua; Hao, Huazhen; Jiang, Lingmin; Liu, Yuling

    2017-01-01

    .... Herein, we proposed a strategy to prepare H. cordata essential oil (HEO) safely and effectively by combining the solvent extraction and the macroporous resin purification flexibly, and then encapsulating it using microemulsion...

  16. Mechanical characterization of cellulose single nanofiber by atomic force microscopy

    Science.gov (United States)

    Zhai, Lindong; Kim, Jeong Woong; Lee, Jiyun; Kim, Jaehwan

    2017-04-01

    Cellulose fibers are strong natural fibers and they are renewable, biodegradable and the most abundant biopolymer in the world. So to develop new cellulose fibers based products, the mechanical properties of cellulose nanofibers would be a key. The atomic microscope is used to measure the mechanical properties of cellulose nanofibers based on 3-points bending of cellulose nanofiber. The cellulose nanofibers were generated for an aqueous counter collision system. The cellulose microfibers were nanosized under 200 MPa high pressure. The cellulose nanofiber suspension was diluted with DI water and sprayed on the silicon groove substrate. By performing a nanoscale 3-points bending test using the atomic force microscopy, a known force was applied on the center of the fiber. The elastic modulus of the single nanofiber is obtained by calculating the fiber deflection and several parameters. The elastic modulus values were obtained from different resources of cellulose such as hardwood, softwood and cotton.

  17. Versatile Molding Process for Tough Cellulose Hydrogel Materials.

    Science.gov (United States)

    Kimura, Mutsumi; Shinohara, Yoshie; Takizawa, Junko; Ren, Sixiao; Sagisaka, Kento; Lin, Yudeng; Hattori, Yoshiyuki; Hinestroza, Juan P

    2015-11-05

    Shape-persistent and tough cellulose hydrogels were fabricated by a stepwise solvent exchange from a homogeneous ionic liquid solution of cellulose exposure to methanol vapor. The cellulose hydrogels maintain their shapes under changing temperature, pH, and solvents. The micrometer-scale patterns on the mold were precisely transferred onto the surface of cellulose hydrogels. We also succeeded in the spinning of cellulose hydrogel fibers through a dry jet-wet spinning process. The mechanical property of regenerated cellulose fibers improved by the drawing of cellulose hydrogel fibers during the spinning process. This approach for the fabrication of tough cellulose hydrogels is a major advance in the fabrication of cellulose-based structures with defined shapes.

  18. Microscope-controlled glass bead blasting: a new technique

    Directory of Open Access Journals (Sweden)

    Peter Kotschy

    2011-01-01

    Full Text Available Peter Kotschy1, Sascha Virnik2, Doris Christ3, Alexander Gaggl21Private Practice, Vienna, Austria; 2Department of Oral and Maxillofacial Surgery, Central Hospital, Klagenfurt, Austria; 3Klagenfurt, AustriaObjective: The aim of periodontal therapy is the healing of periodontal inflammation; the protection of the attachment and the alveolar bone; and the regeneration of the periodontal structures. In the therapy of periodontitis, supra- and subgingival scaling and root planing plays a main role. The procedure described combines perfect root cleaning without scaling and root planing and minimal invasive periodontal surgery without a scalpel.Material and methods: Glass beads of 90 µm were used with the kinetic preparation unit PrepStart® under a pressure of 0.5–5 bar. This technique was practised only under visual control using the OPMI® PRO Magis microscope. Seven examinations were carried out at baseline after 3, 6, 12, 18, 24, and 36 months.Results: Time shows a statistically significant influence on all of the considered target variables (P < 0.0001 for all. As the according estimate is negative, probing depth decreases over time. The major decrease seems to be during the first 6 months. Considering probing depth, plaque on the main effect root shows significant influence (again, P < 0.0001 for all. Observations with high probing depth at the beginning were faster than those with low probing depth. The same characteristic appears by attachment level. Patients with more loss of attachment show more gain.Conclusions: Using microscope-controlled glass bead blasting results in a perfectly clean root surface using visual control (magnification 20×. Microscope-controlled glass bead blasting is therefore a good alternative to periodontal surgery.Keywords: periodontal therapy, microscope, periodontitis

  19. Synthesis and activation of Immobilized beads by natural dye extracts

    Directory of Open Access Journals (Sweden)

    Singh Sanjay

    2012-03-01

    Full Text Available Immobilization technique is used for preservation of enzymes. Here we are using different colors of natural dye in this technique. Our major emphasis would be to create beads of different colors which will act as different carriers for essential enzymes. The need for using colorful dye is because when we need to preserve more than one enzyme then it is helpful in identification of that which enzyme is to be preserved and in which color. Here we used natural dye because most of the chemical dyes are carcinogenic in nature and may alter the nature of preserved enzyme. For this different plant products like mint leaf, rose petal, beat root and Carrot are used for the extraction of dye. In our research studies, we have identified, extracted, characterized, optimized and standardized the natural dyes from plant and microbial sources and we did a comparative study between natural dyes and artificial dyes with respect to different solvent systems like petroleum ether, diethyl ether, acetone, chloroform, ethanol and water systems. The extraction methodologies, characterization, MIC (minimum inhibitory concentration, and solubility studies will be discussed. These immobilization studies will help us to use this application in a variety of fields like in wine stabilization, in modifying the shelf life of food and other natural products which degrade quickly and are difficult to preserve under natural conditions. Here sodium Alginate beads are being used so that there is good number of beads formation and that will help for the proper entrapment of the essential enzymes required for an important reaction in Bio-systems.

  20. Modeling of welded bead profile for rapid prototyping by robotic MAG welding

    Institute of Scientific and Technical Information of China (English)

    CAO Yong; ZHU Sheng; WANG Tao; WANG Wanglong

    2009-01-01

    As a deposition technology, robotic metal active gas(MAG) welding has shown new promise for rapid prototyping (RP) of metallic parts. During the process of metal forming using robotic MAG welding, sectional profile of single-pass welded bead is critical to formed accuracy and quality of metal pans. In this paper, the experiments of single-pass welded bead for rapid prototyping using robotic MAG welding were carried out. The effect of some edge detectors on the cross-sectional edge of welded bead was discussed and curve fitting was applied using leat square fitting. Consequently, the mathematical model of welded bead profile was developed. The experimental results show that good shape could be obtained under suitable welding parameters. Canny operawr is suitable to edge detection of welded bead profile, and the mathematical model of welded bead profile developed is approximately parabola.