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Sample records for hydrophobic-hydrophilic macroporous poly

  1. Switchable Hydrophobic-Hydrophilic Surfaces

    CERN Document Server

    Bunker, B C; Huber, D L; Kent, M S; Kushmerick, J G; Lopez, G P; Manginell, R P; Méndez, S E; Yim, H

    2002-01-01

    Tethered films of poly n-isopropylacrylamide (PNIPAM) films have been developed as materials that can be used to switch the chemistry of a surface in response to thermal activation. In water, PNIPAM exhibits a thermally-activated phase transition that is accompanied by significant changes in polymer volume, water contact angle, and protein adsorption characteristics. New synthesis routes have been developed to prepare PNIPAM films via in-situ polymerization on self-assembled monolayers. Swelling transitions in tethered films have been characterized using a wide range of techniques including surface plasmon resonance, attenuated total reflectance infrared spectroscopy, interfacial force microscopy, neutron reflectivity, and theoretical modeling. PNIPAM films have been deployed in integrated microfluidic systems. Switchable PNIPAM films have been investigated for a range of fluidic applications including fluid pumping via surface energy switching and switchable protein traps for pre-concentrating and separating...

  2. Molecular dynamics simulations of the hydrophobin SC3 at a hydrophobic/hydrophilic interface

    NARCIS (Netherlands)

    Fan, Hao; Wang, Xiaoqin; Zhu, Jiang; Robillard, George T.; Mark, Alan E.

    2006-01-01

    Hydrophobins are small (similar to 100 aa) proteins that have an important role in the growth and development of mycelial fungi. They are surface active and, after secretion by the fungi, self-assemble into amphipathic membranes at hydrophobic/hydrophilic interfaces, reversing the hydrophobicity of

  3. Preparation of Macroporous Poly (vinyl alcohol-co-triallyl isocyanurate) Beads Bearing Aminocarboxylic Acid as Functional Groups by Suspension Polymerization

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    Macroporous poly (vinyl acetate-co-triallyl isocyanurate) beads were prepared with suspension polymerization method. The copolymer beads were then transformed into poly (vinyl alcohol-co-triallyl isocyanurate) by ester exchange reaction. Aminocarboxylic acids were immobilized on the copolymer beads by the esterification of hydroxyl groups with diethyl-lenetriaminepentaacetic bisanhydride. The weak acid exchange capacities, specific surface areas and mean pore diameters of the resultant resin beads were measured.

  4. Enhancement of Water Evaporation on Solid Surfaces with Nanoscale Hydrophobic-Hydrophilic Patterns.

    Science.gov (United States)

    Wan, Rongzheng; Wang, Chunlei; Lei, Xiaoling; Zhou, Guoquan; Fang, Haiping

    2015-11-06

    Using molecular dynamics simulations, we show that the evaporation of nanoscale water on hydrophobic-hydrophilic patterned surfaces is unexpectedly faster than that on any surfaces with uniform wettability. The key to this phenomenon is that, on the patterned surface, the evaporation rate from the hydrophilic region only slightly decreases due to the correspondingly increased water thickness; meanwhile, a considerable number of water molecules evaporate from the hydrophobic region despite the lack of water film. Most of the evaporated water from the hydrophobic region originates from the hydrophilic region by diffusing across the contact lines. Further analysis shows that the evaporation rate from the hydrophobic region is approximately proportional to the total length of the contact lines.

  5. Membrane morphological study nanostructured based hydrophobic/hydrophilic applied in devices of PEMFC

    International Nuclear Information System (INIS)

    Loureiro, Felipe Augusto M.; Dahmouche, K; Rocco, Ana Maria

    2015-01-01

    The increasingly high energy demand generated by the increase of world population and consumption of fuels based on non-renewable sources has stimulated, in recent decades, the development of alternatives with less environmental impact and are based on renewable sources. Among these, the fuel cells (FC) have extremely promising possibilities. For the development of FC with market viability, it is necessary to obtain materials with optimized properties, among which the proton conducting membranes. In this work, we developed semi-interpenetrating polymer membranes (SIPN) based on diglycidyl ether of bisphenol-A (DGEBA) and polyethyleneimine (PEI), aiming their application in PEMFC. The membranes nanostructure was studied by AFM and SAXS means and it was identified ordinate hydrophobic/hydrophilic nano domains, which have determined the membrane properties, specially the proton conductivity. (author)

  6. Laser micro-machining of hydrophobic-hydrophilic patterns for fluid driven self-alignment in micro-assembly

    NARCIS (Netherlands)

    Römer, Gerardus Richardus, Bernardus, Engelina; Jorritsma, Mark; Arnaldo del Cerro, D.; Chang, Bo; Liimatainen, Ville; Zhou, Quan; Huis in 't Veld, Bert

    2011-01-01

    Fluid driven self-alignment is a low cost alternative to fast but relatively inaccurate robotic pickand-place assembly of micro-fabricated components. This fluidic self-alignment technique relies on a hydrophobic-hydrophilic pattern on the surface of the receiving substrate, which confines a fluid

  7. Hydrophobic/Hydrophilic Cooperative Janus System for Enhancement of Fog Collection.

    Science.gov (United States)

    Cao, Moyuan; Xiao, Jiasheng; Yu, Cunming; Li, Kan; Jiang, Lei

    2015-09-09

    Harvesting micro-droplets from fog is a promising method for solving global freshwater crisis. Different types of fog collectors have been extensively reported during the last decade. The improvement of fog collection can be attributed to the immediate transportation of harvested water, the effective regeneration of the fog gathering surface, etc. Through learning from the nature's strategy for water preservation, the hydrophobic/hydrophilic cooperative Janus system that achieved reinforced fog collection ability is reported here. Directional delivery of the surface water, decreased re-evaporation rate of the harvested water, and thinner boundary layer of the collecting surface contribute to the enhancement of collection efficiency. Further designed cylinder Janus collector can facilely achieve a continuous process of efficient collection, directional transportation, and spontaneous preservation of fog water. This Janus fog harvesting system should improve the understanding of micro-droplet collection system and offer ideas to solve water resource crisis. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Macropores and macropore transport

    DEFF Research Database (Denmark)

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

    2012-01-01

    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...

  9. Monodisperse macroporous poly(glycidyl methacrylate) microspheres coated with silica: Design, preparation and characterization

    Czech Academy of Sciences Publication Activity Database

    Grama, Silvia; Plichta, Zdeněk; Trchová, Miroslava; Kovářová, Jana; Beneš, Milan J.; Horák, Daniel

    2014-01-01

    Roč. 77, April (2014), s. 11-17 ISSN 1381-5148 R&D Projects: GA MŠk EE2.3.30.0029 Institutional support: RVO:61389013 Keywords : multistep swelling polymerization * poly(glycidyl methacrylate) * poly(2,3-dihydroxypropyl methacrylate) Subject RIV: CE - Biochemistry Impact factor: 2.515, year: 2014

  10. On the Mechanical Properties of HIPE Templated Macroporous Poly(dicyclopentadiene) Prepared with Low Surfactant Amounts

    Czech Academy of Sciences Publication Activity Database

    Kovačič, S.; Matsko, N.B.; Jeřábek, Karel; Krajnc, P.; Slugovc, Ch.

    2013-01-01

    Roč. 1, č. 3 (2013), s. 487-490 ISSN 2050-7488 Institutional support: RVO:67985858 Keywords : cellular structure * surfactant * polyHIPE chemistry Subject RIV: CI - Industrial Chemistry, Chemical Engineering

  11. Chondrogenic potential of macroporous biodegradable cryogels based on synthetic poly(.alpha.-amino acids)

    Czech Academy of Sciences Publication Activity Database

    Sedlačík, Tomáš; Acar, O. K.; Studenovská, Hana; Kotelnikov, Ilya; Kučka, Jan; Konečná, Z.; Zikmund, T.; Kaiser, J.; Köse, G. T.; Rypáček, František

    2018-01-01

    Roč. 14, č. 2 (2018), s. 228-238 ISSN 1744-683X Institutional support: RVO:61389013 Keywords : poly( amino acids ) * cryogelation * scaffold Subject RIV: CD - Macromolecular Chemistry OBOR OECD: Polymer science Impact factor: 3.889, year: 2016

  12. In vitro mechanical fatigue behavior of poly-ɛ-caprolactone macroporous scaffolds for cartilage tissue engineering: Influence of pore filling by a poly(vinyl alcohol) gel.

    Science.gov (United States)

    Panadero, J A; Vikingsson, L; Gomez Ribelles, J L; Lanceros-Mendez, S; Sencadas, V

    2015-07-01

    Polymeric scaffolds used in regenerative therapies are implanted in the damaged tissue and submitted to repeated loading cycles. In the case of articular cartilage engineering, an implanted scaffold is typically subjected to long-term dynamic compression. The evolution of the mechanical properties of the scaffold during bioresorption has been deeply studied in the past, but the possibility of failure due to mechanical fatigue has not been properly addressed. Nevertheless, the macroporous scaffold is susceptible to failure after repeated loading-unloading cycles. In this work fatigue studies of polycaprolactone scaffolds were carried by subjecting the scaffold to repeated compression cycles in conditions simulating the scaffold implanted in the articular cartilage. The behavior of the polycaprolactone sponge with the pores filled with a poly(vinyl alcohol) gel simulating the new formed tissue within the pores was compared with that of the material immersed in water. Results were analyzed with Morrow's criteria for failure and accurate fittings are obtained just up to 200 loading cycles. It is also shown that the presence of poly(vinyl alcohol) increases the elastic modulus of the scaffolds, the effect being more pronounced with increasing the number of freeze/thawing cycles. © 2014 Wiley Periodicals, Inc.

  13. Macroporous poly(vinyl alcohol) microspheres bearing phosphate groups as a new adsorbent for low-density lipoprotein apheresis

    Energy Technology Data Exchange (ETDEWEB)

    Wang Weichao; Xie Hui; Ou Lailiang; Wang Lianyong; Yu Yaoting; Kong Deling [Key Laboratory of Bioactive Materials, Ministry of Education, College of Life Science, Nankai University, Tianjin 300071 (China); Sun Lisha, E-mail: wly@nankai.edu.c, E-mail: kongdeling@nankai.edu.c [General Hospital, Tianjin Medical University, Tianjin 300052 (China)

    2009-12-15

    A new low-density lipoprotein (LDL) adsorbent with phosphate groups as the ligand was prepared in this study. Macroporous poly(vinyl acetate-co-triallyl isocyanurate) microspheres were prepared using a free-radical suspension polymerization method. A hydrolysis reaction in sodium hydroxide/methanol changed the materials into poly(vinyl alcohol) (PVA) microspheres. Further reaction with phosphorus oxychloride in anhydrous DMF led to the LDL adsorbent PVA-phosphate microspheres. The preparation conditions such as reaction time, temperature and the amount of phosphorus oxychloride were optimized. The adsorption of plasma lipoproteins was examined by in vitro adsorption assays. The influence of adsorption time, plasma volume and ionic strength on the adsorption capacity was investigated. The circulation adsorption showed that the pathogenic lipoproteins in the plasma such as total cholesterol (TC), LDL and triglyceride (TG) could be removed markedly, in which the removal percentages were 42.9%, 45.0% and 44.74%, respectively. However, the reduction of high-density lipoprotein (HDL) and other normal plasma components was very slight. For in vivo experiment, rabbits were fed with high-cholesterol food to develop a hyperlipidemia model and treated by extracorporeal blood perfusion using the PVA-phosphate columns. Eight hyperlipidemia rabbits were treated with the PVA-phosphate adsorbent, and the removal of TC, LDL and TG was 45.03 +- 6.64%, 48.97 +- 9.92% and 35.42 +- 14.17%, respectively. The sterilization and storage tests showed that the adsorbent was chemically and functionally stable. It could be easily sterilized by a common method and stored for months without loss of adsorption capacity. Therefore, this new PVA-phosphate-based LDL adsorbent may have potential for application in LDL apheresis.

  14. Macroporous poly(vinyl alcohol) microspheres bearing phosphate groups as a new adsorbent for low-density lipoprotein apheresis

    International Nuclear Information System (INIS)

    Wang Weichao; Xie Hui; Ou Lailiang; Wang Lianyong; Yu Yaoting; Kong Deling; Sun Lisha

    2009-01-01

    A new low-density lipoprotein (LDL) adsorbent with phosphate groups as the ligand was prepared in this study. Macroporous poly(vinyl acetate-co-triallyl isocyanurate) microspheres were prepared using a free-radical suspension polymerization method. A hydrolysis reaction in sodium hydroxide/methanol changed the materials into poly(vinyl alcohol) (PVA) microspheres. Further reaction with phosphorus oxychloride in anhydrous DMF led to the LDL adsorbent PVA-phosphate microspheres. The preparation conditions such as reaction time, temperature and the amount of phosphorus oxychloride were optimized. The adsorption of plasma lipoproteins was examined by in vitro adsorption assays. The influence of adsorption time, plasma volume and ionic strength on the adsorption capacity was investigated. The circulation adsorption showed that the pathogenic lipoproteins in the plasma such as total cholesterol (TC), LDL and triglyceride (TG) could be removed markedly, in which the removal percentages were 42.9%, 45.0% and 44.74%, respectively. However, the reduction of high-density lipoprotein (HDL) and other normal plasma components was very slight. For in vivo experiment, rabbits were fed with high-cholesterol food to develop a hyperlipidemia model and treated by extracorporeal blood perfusion using the PVA-phosphate columns. Eight hyperlipidemia rabbits were treated with the PVA-phosphate adsorbent, and the removal of TC, LDL and TG was 45.03 ± 6.64%, 48.97 ± 9.92% and 35.42 ± 14.17%, respectively. The sterilization and storage tests showed that the adsorbent was chemically and functionally stable. It could be easily sterilized by a common method and stored for months without loss of adsorption capacity. Therefore, this new PVA-phosphate-based LDL adsorbent may have potential for application in LDL apheresis.

  15. Macroporous modified poly (vinyl alcohol) hydrogels with charged groups for tissue engineering: Preparation and in vitro evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Drozdova, Maria G., E-mail: drozdovamg@gmail.com [Polymers for Biology Laboratory, Shemyakin & Ovchinnikov Institute of Bioorganic Chemistry of Russian Academy of Sciences, Miklukho-Maklaya str., 16/10, Moscow 117997 (Russian Federation); Zaytseva-Zotova, Daria S. [Polymers for Biology Laboratory, Shemyakin & Ovchinnikov Institute of Bioorganic Chemistry of Russian Academy of Sciences, Miklukho-Maklaya str., 16/10, Moscow 117997 (Russian Federation); Akasov, Roman A. [Polymers for Biology Laboratory, Shemyakin & Ovchinnikov Institute of Bioorganic Chemistry of Russian Academy of Sciences, Miklukho-Maklaya str., 16/10, Moscow 117997 (Russian Federation); Sechenov First Moscow State Medical University, Institute for Regenerative Medicine, Trubetskaya str., 8/2, Moscow 119048 (Russian Federation); Golunova, Anna S.; Artyukhov, Alexander A. [D. Mendeleyev University of Chemical Technology of Russia, Miusskaya Square 9, Moscow 125047 (Russian Federation); Udartseva, Olga O.; Andreeva, Elena R. [Institute of Biomedical Problems of Russian Academy of Sciences, Khoroshevskoe Shosse 76a, Moscow 123007 (Russian Federation); Lisovyy, Denis E.; Shtilman, Michael I. [D. Mendeleyev University of Chemical Technology of Russia, Miusskaya Square 9, Moscow 125047 (Russian Federation); Markvicheva, Elena A. [Polymers for Biology Laboratory, Shemyakin & Ovchinnikov Institute of Bioorganic Chemistry of Russian Academy of Sciences, Miklukho-Maklaya str., 16/10, Moscow 117997 (Russian Federation)

    2017-06-01

    Poly(vinyl alcohol) (PVA) hydrogels are widely employed for various biomedical applications, including tissue engineering, due to their biocompatibility, high water solubility, low protein adsorption, and chemical stability. However, non-charged surface of PVA-based hydrogels is not optimal for cell adhesion and spreading. Here, cross-linked macroporous hydrogels based on low molecular weight acrylated PVA (Acr-PVA) was synthesized by modification of the pendant alcohol groups on the PVA with glycidyl methacrylate (GMA). To enhance cell affinity, charged groups were introduced to the hydrogel composition. For this purpose, Acr-PVA was copolymerized with either negatively charged acrylic acid (AA) or positively charged 2-(diethylamino) ethyl methacrylate (DEAEMA) monomers. A surface charge of the obtained hydrogels was found to be in function of the co-monomer type and content. Confocal microscopy observations confirmed that adhesion and spreading of both mouse fibroblasts (L929) and human mesenchymal stem cells (hMSC) on the modified Acr-PVA-AA and Acr-PVA-DEAEMA hydrogels were better than those on the non-modified Acr-PVA hydrogel. The increase of DEAEMA monomer content from 5 to 15 mol% resulted in the enhancement of cell viability which was 1.5-fold higher for Acr-PVA-DEAEMA-15 hydrogel than that of the non-modified Acr-PVA hydrogel sample. - Highlights: • To enhance cell affinity, acrylated PVA hydrogel was modified with AA or DEAEMA monomers. • Cell adhesion and spreading were found to depend on the co-monomer type and content. • Proliferation of L929 fibroblasts and stem cells increased on the modified hydrogels.

  16. Macroporous modified poly (vinyl alcohol) hydrogels with charged groups for tissue engineering: Preparation and in vitro evaluation

    International Nuclear Information System (INIS)

    Drozdova, Maria G.; Zaytseva-Zotova, Daria S.; Akasov, Roman A.; Golunova, Anna S.; Artyukhov, Alexander A.; Udartseva, Olga O.; Andreeva, Elena R.; Lisovyy, Denis E.; Shtilman, Michael I.; Markvicheva, Elena A.

    2017-01-01

    Poly(vinyl alcohol) (PVA) hydrogels are widely employed for various biomedical applications, including tissue engineering, due to their biocompatibility, high water solubility, low protein adsorption, and chemical stability. However, non-charged surface of PVA-based hydrogels is not optimal for cell adhesion and spreading. Here, cross-linked macroporous hydrogels based on low molecular weight acrylated PVA (Acr-PVA) was synthesized by modification of the pendant alcohol groups on the PVA with glycidyl methacrylate (GMA). To enhance cell affinity, charged groups were introduced to the hydrogel composition. For this purpose, Acr-PVA was copolymerized with either negatively charged acrylic acid (AA) or positively charged 2-(diethylamino) ethyl methacrylate (DEAEMA) monomers. A surface charge of the obtained hydrogels was found to be in function of the co-monomer type and content. Confocal microscopy observations confirmed that adhesion and spreading of both mouse fibroblasts (L929) and human mesenchymal stem cells (hMSC) on the modified Acr-PVA-AA and Acr-PVA-DEAEMA hydrogels were better than those on the non-modified Acr-PVA hydrogel. The increase of DEAEMA monomer content from 5 to 15 mol% resulted in the enhancement of cell viability which was 1.5-fold higher for Acr-PVA-DEAEMA-15 hydrogel than that of the non-modified Acr-PVA hydrogel sample. - Highlights: • To enhance cell affinity, acrylated PVA hydrogel was modified with AA or DEAEMA monomers. • Cell adhesion and spreading were found to depend on the co-monomer type and content. • Proliferation of L929 fibroblasts and stem cells increased on the modified hydrogels.

  17. Direct-injection HPLC method of measuring micafungin in human plasma using a novel hydrophobic/hydrophilic hybrid ODS column.

    Science.gov (United States)

    Uranishi, Hiroaki; Nakamura, Mitsuhiro; Nakamura, Hiroki; Ikeda, Yukari; Otsuka, Mayuko; Kato, Zenichiro; Tsuchiya, Teruo

    2011-04-15

    A direct-injection HPLC-based method has been developed for determining amounts of micafungin in human plasma using a novel hydrophobic/hydrophilic hybrid ODS column. The method is easy to perform and requires only 10 μL of a filtered plasma sample. The chromatographic separations were carried out with a gradient mode. The fluorescence detection wavelengths of excitation and emission were set at 273 nm and 464 nm, respectively. Retention times for micafungin and IS were 22.4 and 23.7 min, respectively. Micafungin and FR195743 (IS) peaks were completely separated with little tailing, and no interference was observed. The calibration curve of micafungin showed good linearity in the range of 0.5-20.0 μg/mL (r(2)=1.00). The intra-day accuracy ranged from -4.5 to 5.3%. The inter-day accuracy ranged from -9.8 to 1.5%. The precisions were less than 10%. This method is useful for the determination of micafungin in human plasma. Copyright © 2011 Elsevier B.V. All rights reserved.

  18. Insight into the cryopolymerization to form a poly(N-isopropylacrylamide)/clay macroporous gel: structure and phase evolution

    Czech Academy of Sciences Publication Activity Database

    Strachota, Beata; Matějka, Libor; Sikora, Antonín; Spěváček, Jiří; Konefal, Rafal; Zhigunov, Alexander; Šlouf, Miroslav

    2017-01-01

    Roč. 13, č. 6 (2017), s. 1244-1256 ISSN 1744-683X R&D Projects: GA ČR(CZ) GA13-23392S; GA MŠk(CZ) LD14010 Grant - others:European Commission(XE) COST Action MP1202 HINT Institutional support: RVO:61389013 Keywords : macroporous gels * nanocomposite cryogels * polymer-clay hydrogel Subject RIV: CD - Macromolecular Chemistry OBOR OECD: Polymer science Impact factor: 3.889, year: 2016

  19. Role of long- and short-range hydrophobic, hydrophilic and charged residues contact network in protein’s structural organization

    Directory of Open Access Journals (Sweden)

    Sengupta Dhriti

    2012-06-01

    Full Text Available Abstract Background The three-dimensional structure of a protein can be described as a graph where nodes represent residues and the strength of non-covalent interactions between them are edges. These protein contact networks can be separated into long and short-range interactions networks depending on the positions of amino acids in primary structure. Long-range interactions play a distinct role in determining the tertiary structure of a protein while short-range interactions could largely contribute to the secondary structure formations. In addition, physico chemical properties and the linear arrangement of amino acids of the primary structure of a protein determines its three dimensional structure. Here, we present an extensive analysis of protein contact subnetworks based on the London van der Waals interactions of amino acids at different length scales. We further subdivided those networks in hydrophobic, hydrophilic and charged residues networks and have tried to correlate their influence in the overall topology and organization of a protein. Results The largest connected component (LCC of long (LRN-, short (SRN- and all-range (ARN networks within proteins exhibit a transition behaviour when plotted against different interaction strengths of edges among amino acid nodes. While short-range networks having chain like structures exhibit highly cooperative transition; long- and all-range networks, which are more similar to each other, have non-chain like structures and show less cooperativity. Further, the hydrophobic residues subnetworks in long- and all-range networks have similar transition behaviours with all residues all-range networks, but the hydrophilic and charged residues networks don’t. While the nature of transitions of LCC’s sizes is same in SRNs for thermophiles and mesophiles, there exists a clear difference in LRNs. The presence of larger size of interconnected long-range interactions in thermophiles than mesophiles, even at

  20. Sorption of different phenol derivatives on functionalized macroporous nanocomposite of poly (glycidyl methacrylate-co-ethylene glycol dimethacrylate and acid modified bentonite

    Directory of Open Access Journals (Sweden)

    Marinović Sanja R.

    2014-01-01

    Full Text Available Macroporous nanocomposite of poly (glycidyl methacrylate-co-ethylene glycol dimethacrylate and acid modified bentonite was prepared by radical suspension copolymerization. Nanocomposite was functionalized with diethylene triamine (deta, by ring-opening reaction of the pendant epoxy groups. Functionalization was performed in order to enable phenol derivatives sorption. This new, not sufficiently investigated material, with developed porous structure was denoted CP-SA-deta. In this study, the influence of temperature on 4-nitrophenol (4NP sorption on CP-SA-deta was investigated. The chemisorption was estimated as dominant process since activation energy of sorption of 4NP of 54.8 kJ mol-1 was obtained. After determining the optimal sorption conditions for 4NP, the sorption of 2-nitrophenol (2NP and 2-chloro 4-nitrophenol (2Cl4NP on CP-SA-deta was investigated with respect to pH, initial concentration and contact time. The 2NP sorption was seldom tested, while according to our knowledge, the 2Cl4NP sorption was not investigated. The isotherm data were best fitted with Langmuir model, while the sorption dynamics obeyed the pseudo-second-order kinetic model for all derivatives. [Projekat Ministarstva nauke Republike Srbije, br. III 45001 i br. III 43009

  1. Parallel fabrication of macroporous scaffolds.

    Science.gov (United States)

    Dobos, Andrew; Grandhi, Taraka Sai Pavan; Godeshala, Sudhakar; Meldrum, Deirdre R; Rege, Kaushal

    2018-07-01

    Scaffolds generated from naturally occurring and synthetic polymers have been investigated in several applications because of their biocompatibility and tunable chemo-mechanical properties. Existing methods for generation of 3D polymeric scaffolds typically cannot be parallelized, suffer from low throughputs, and do not allow for quick and easy removal of the fragile structures that are formed. Current molds used in hydrogel and scaffold fabrication using solvent casting and porogen leaching are often single-use and do not facilitate 3D scaffold formation in parallel. Here, we describe a simple device and related approaches for the parallel fabrication of macroporous scaffolds. This approach was employed for the generation of macroporous and non-macroporous materials in parallel, in higher throughput and allowed for easy retrieval of these 3D scaffolds once formed. In addition, macroporous scaffolds with interconnected as well as non-interconnected pores were generated, and the versatility of this approach was employed for the generation of 3D scaffolds from diverse materials including an aminoglycoside-derived cationic hydrogel ("Amikagel"), poly(lactic-co-glycolic acid) or PLGA, and collagen. Macroporous scaffolds generated using the device were investigated for plasmid DNA binding and cell loading, indicating the use of this approach for developing materials for different applications in biotechnology. Our results demonstrate that the device-based approach is a simple technology for generating scaffolds in parallel, which can enhance the toolbox of current fabrication techniques. © 2018 Wiley Periodicals, Inc.

  2. Controlled release of ibuprofen by meso–macroporous silica

    Energy Technology Data Exchange (ETDEWEB)

    Santamaría, E., E-mail: esthersantamaria@ub.edu; Maestro, A.; Porras, M.; Gutiérrez, J.M.; González, C.

    2014-02-15

    Structured meso–macroporous silica was successfully synthesized from an O/W emulsion using decane as a dispersed phase. Sodium silicate solution, which acts as a silica source and a poly(ethylene oxide)–poly(propylene oxide)–poly(ethylene oxide) (EO{sub 19}PO{sub 39}EO{sub 19}) denoted as P84 was used in order to stabilize the emulsion and as a mesopore template. The materials obtained were characterized through transmission electron microscopy (TEM), scanning electron microscopy (SEM), small-angle X-ray diffraction scattering (SAXS) and nitrogen adsorption–desorption isotherms. Ibuprofen (IBU) was selected as the model drug and loaded into ordered meso–macroporous materials. The effect of the materials’ properties on IBU drug loading and release was studied. The results showed that the loading of IBU increases as the macropore presence in the material is increased. The IBU adsorption process followed the Langmuir adsorption isotherm. A two-step release process, consisting of an initial fast release and then a slower release was observed. Macropores enhanced the adsorption capacity of the material; this was probably due to the fact that they allowed the drug to access internal pores. When only mesopores were present, ibuprofen was probably adsorbed on the mesopores close to the surface. Moreover, the more macropore present in the material, the slower the release behaviour observed, as the ibuprofen adsorbed in the internal pores had to diffuse along the macropore channels up to the surface of the material. The material obtained from a highly concentrated emulsion was functionalized with amino groups using two methods, the post-grafting mechanism and the co-condensation mechanism. Both routes improve IBU adsorption in the material and show good behaviour as a controlled drug delivery system. - Graphical abstract: Ibuprofen release profiles for the materials obtained from samples P84{sub m}eso (black diamonds), P84{sub 2}0% (white squares), P84{sub 5

  3. Controlled release of ibuprofen by meso–macroporous silica

    International Nuclear Information System (INIS)

    Santamaría, E.; Maestro, A.; Porras, M.; Gutiérrez, J.M.; González, C.

    2014-01-01

    Structured meso–macroporous silica was successfully synthesized from an O/W emulsion using decane as a dispersed phase. Sodium silicate solution, which acts as a silica source and a poly(ethylene oxide)–poly(propylene oxide)–poly(ethylene oxide) (EO 19 PO 39 EO 19 ) denoted as P84 was used in order to stabilize the emulsion and as a mesopore template. The materials obtained were characterized through transmission electron microscopy (TEM), scanning electron microscopy (SEM), small-angle X-ray diffraction scattering (SAXS) and nitrogen adsorption–desorption isotherms. Ibuprofen (IBU) was selected as the model drug and loaded into ordered meso–macroporous materials. The effect of the materials’ properties on IBU drug loading and release was studied. The results showed that the loading of IBU increases as the macropore presence in the material is increased. The IBU adsorption process followed the Langmuir adsorption isotherm. A two-step release process, consisting of an initial fast release and then a slower release was observed. Macropores enhanced the adsorption capacity of the material; this was probably due to the fact that they allowed the drug to access internal pores. When only mesopores were present, ibuprofen was probably adsorbed on the mesopores close to the surface. Moreover, the more macropore present in the material, the slower the release behaviour observed, as the ibuprofen adsorbed in the internal pores had to diffuse along the macropore channels up to the surface of the material. The material obtained from a highly concentrated emulsion was functionalized with amino groups using two methods, the post-grafting mechanism and the co-condensation mechanism. Both routes improve IBU adsorption in the material and show good behaviour as a controlled drug delivery system. - Graphical abstract: Ibuprofen release profiles for the materials obtained from samples P84 m eso (black diamonds), P84 2 0% (white squares), P84 5 0% (black triangles), P84 7

  4. Controlled release of ibuprofen by meso-macroporous silica

    Science.gov (United States)

    Santamaría, E.; Maestro, A.; Porras, M.; Gutiérrez, J. M.; González, C.

    2014-02-01

    Structured meso-macroporous silica was successfully synthesized from an O/W emulsion using decane as a dispersed phase. Sodium silicate solution, which acts as a silica source and a poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) (EO19PO39EO19) denoted as P84 was used in order to stabilize the emulsion and as a mesopore template. The materials obtained were characterized through transmission electron microscopy (TEM), scanning electron microscopy (SEM), small-angle X-ray diffraction scattering (SAXS) and nitrogen adsorption-desorption isotherms. Ibuprofen (IBU) was selected as the model drug and loaded into ordered meso-macroporous materials. The effect of the materials’ properties on IBU drug loading and release was studied. The results showed that the loading of IBU increases as the macropore presence in the material is increased. The IBU adsorption process followed the Langmuir adsorption isotherm. A two-step release process, consisting of an initial fast release and then a slower release was observed. Macropores enhanced the adsorption capacity of the material; this was probably due to the fact that they allowed the drug to access internal pores. When only mesopores were present, ibuprofen was probably adsorbed on the mesopores close to the surface. Moreover, the more macropore present in the material, the slower the release behaviour observed, as the ibuprofen adsorbed in the internal pores had to diffuse along the macropore channels up to the surface of the material. The material obtained from a highly concentrated emulsion was functionalized with amino groups using two methods, the post-grafting mechanism and the co-condensation mechanism. Both routes improve IBU adsorption in the material and show good behaviour as a controlled drug delivery system.

  5. Incorporation of a Cationic Conjugated Polyelectrolyte CPE within an Aqueous Poly(vinyl alcohol) Sol

    DEFF Research Database (Denmark)

    Knaapila, Matti; Stewart, Beverly; Costa, Telma

    2016-01-01

    We report on a multiscale polymer-within-polymer structure of the cationic conjugated polyelectrolyte poly{[9,9-bis(6-N,N,N-trimethylammonium)hexyl]fluorene phenylene} (HTMAPFP) in aqueous poly(vinyl alcohol).(PVA) sol. Molecular dynamics simulations and small-angle neutron scattering (SANS) data...... show that HTMA-PFP forms aggregates in water but becomes entangled by PVA (with a 1:1 molar ratio of HTMA-PFP to PVA) and eventually immersed in PVA clusters (with the ratio 1:4). This is attributed to the hydrophobic hydrophilic balance. Contrast variation data with regular and deuterated PVA support...

  6. [Advances of poly (ionic liquid) materials in separation science].

    Science.gov (United States)

    Liu, Cuicui; Guo, Ting; Su, Rina; Gu, Yuchen; Deng, Qiliang

    2015-11-01

    Ionic liquids, as novel ionization reagents, possess beneficial characteristics including good solubility, conductivity, thermal stability, biocompatibility, low volatility and non-flammability. Ionic liquids are attracting a mass of attention of analytical chemists. Poly (ionic liquid) materials have common performances of ionic liquids and polymers, and have been successfully applied in separation science area. In this paper, we discuss the interaction mechanisms between the poly(ionic liquid) materials and analytes including hydrophobic/hydrophilic interactions, hydrogen bond, ion exchange, π-π stacking and electrostatic interactions, and summarize the application advances of the poly(ionic liquid) materials in solid phase extraction, chromatographic separation and capillary electrophoresis. At last, we describe the future prospect of poly(ionic liquid) materials.

  7. 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...

  8. Factorization of Transport Coefficients in Macroporous Media

    DEFF Research Database (Denmark)

    Shapiro, Alexander; Stenby, Erling Halfdan

    2000-01-01

    We prove the fundamental theorem about factorization of the phenomenological coefficients for transport in macroporous media. By factorization we mean the representation of the transport coefficients as products of geometric parameters of the porous medium and the parameters characteristic...

  9. Deep Ultraviolet Macroporous Silicon Filters, Phase I

    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...

  10. Use of macroporous plastics in extraction chromatography

    International Nuclear Information System (INIS)

    Braun, T.; Farac, A.B.

    1978-01-01

    Possibilities are analysed which the use of porous plastics (polyvinyl chloride, siloxane rubber, polyurethane, polystyrene and etc.) as carriers presents in extraction chromatography. Short characteristics of chemical and physical properties of macroporous carriers is given. The importance of correct chromatographic column packing is noted to obtain columns with good hydrodynamic characteristics and operational properties. Examples of using columns with macroporous carriers in radiochemistry and inorganic chemistry for element separation are given

  11. Development of breathable hydrophobic/hydrophilic functional textiles

    NARCIS (Netherlands)

    Agrawal, P. (Pramod); Brink, G.J. (Ger)

    2013-01-01

    The proposed bi-functional protective structure intended to have hydrophilic interior towards the skin surface and hydrophobic exterior for protection, ensuring fast transfer of moisture between body and external environment. The sandwich structure is prepared using 100% wool jersey and varieties of

  12. Macroporous biodegradable cryogels of synthetic poly(.alpha.-amino acids)

    Czech Academy of Sciences Publication Activity Database

    Sedlačík, Tomáš; Proks, Vladimír; Šlouf, Miroslav; Dušková-Smrčková, Miroslava; Studenovská, Hana; Rypáček, František

    2015-01-01

    Roč. 16, č. 11 (2015), s. 3455-3465 ISSN 1525-7797 R&D Projects: GA ČR GAP108/12/1538 Institutional support: RVO:61389013 Keywords : cryogelation * hydrogel * scaffold Subject RIV: CD - Macromolecular Chemistry Impact factor: 5.583, year: 2015

  13. activity of enzyme trypsin immobilized onto macroporous poly(epoxy

    African Journals Online (AJOL)

    dell

    consequential effects of covalent immobilization. EXPERIMENTAL. Materials .... immersed into water bath. ... storage stability of the enzyme was studied ... pore size range of about 10 to 150 µm. ... figures, the differences in activities (slopes.

  14. Polystyrene-block-Poly(ionic liquid) Copolymers as Work Function Modifiers in Inverted Organic Photovoltaic Cells.

    Science.gov (United States)

    Park, Jong Baek; Isik, Mehmet; Park, Hea Jung; Jung, In Hwan; Mecerreyes, David; Hwang, Do-Hoon

    2018-02-07

    Interfacial layers play a critical role in building up the Ohmic contact between electrodes and functional layers in organic photovoltaic (OPV) solar cells. These layers are based on either inorganic oxides (ZnO and TiO 2 ) or water-soluble organic polymers such as poly[(9,9-dioctyl-2,7-fluorene)-alt-(9,9-bis(3'-(N,N-dimethylamino)propyl)-2,7-fluorene)] and polyethylenimine ethoxylated (PEIE). In this work, we have developed a series of novel poly(ionic liquid) nonconjugated block copolymers for improving the performance of inverted OPV cells by using them as work function modifiers of the indium tin oxide (ITO) cathode. Four nonconjugated polyelectrolytes (n-CPEs) based on polystyrene and imidazolium poly(ionic liquid) (PSImCl) were synthesized by reversible addition-fragmentation chain transfer polymerization. The ratio of hydrophobic/hydrophilic block copolymers was varied depending on the ratio of polystyrene to the PSImCl block. The ionic density, which controls the work function of the electrode by forming an interfacial dipole between the electrode and the block copolymers, was easily tuned by simply changing the PSImCl molar ratio. The inverted OPV device with the ITO/PS 29 -b-PSImCl 60 cathode achieved the best power conversion efficiency (PCE) of 7.55% among the synthesized block copolymers, exhibiting an even higher PCE than that of the reference OPV device with PEIE (7.30%). Furthermore, the surface properties of the block copolymers films were investigated by contact angle measurements to explore the influence of the controlled hydrophobic/hydrophilic characters on the device performances.

  15. Textural properties of poly(glycidyl methacrylate) : acid-modified bentonite nanocomposites

    NARCIS (Netherlands)

    Zunic, M.; Milutinovic-Nikolic, A.; Nastasovic, A.; Vukovic, Z.; Loncarevic, D.; Vukovic, I.; Loos, K.; ten Brinke, G.; Jovanovic, D.; Sharma, Bhaskar; Ubaghs, Luc; Keul, Helmut; Höcker, Hartwig; Loontjens, Ton; Benthem, Rolf van; Žunić, M.; Milutinović-Nikolić, A.; Nastasović, A.; Vuković, Z.; Lončarević, D.; Vuković, I.; Jovanović, D.

    The aim of this study was to obtain enhanced textural properties of macroporous crosslinked copolymer poly(glycidyl methacrylate-co-ethylene glycol dimethacrylate) by synthesizing nanocomposites with acid-modified bentonite. Nanocomposites were obtained by introducing various amounts of

  16. 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.

  17. Photoconductivity relaxation and electron transport in macroporous silicon structures

    Directory of Open Access Journals (Sweden)

    L.A. Karachevtseva

    2017-12-01

    Full Text Available Kinetics and temperature dependence of photoconductivity were measured in macroporous silicon at 80…300 K after light illumination with the wavelength 0.9 μm. The influence of mechanisms of the charge carrier transport through the macropore surface barrier on the kinetics of photoconductivity at various temperatures was investigated. The kinetics of photoconductivity distribution in macroporous silicon and Si substrate has been calculated using the finite-difference time-domain method. The maximum of photoconductivity has been found both in the layer of macroporous silicon and in the monocrystalline substrate. The kinetics of photoconductivity distribution in macroporous silicon showed rapid relaxation of the photoconductivity maximum in the layer of macroporous silicon and slow relaxation of it in the monocrystalline substrate.

  18. Covalently coating dextran on macroporous polyglycidyl methacrylate microsphere enabled rapid protein chromatographic separation

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Rongyue; Li, Qiang; Li, Juan; Zhou, Weiqing; Ye, Peili; Gao, Yang; Ma, Guanghui, E-mail: ghma@home.ipe.ac.cn; Su, Zhiguo

    2012-12-01

    Protein denaturation and nonspecific adsorption on polymer media as a chromatographic support have been a problem which needs to be overcome. Macroporous poly(glycidyl methacrylate-divinylbezene) (PGMA-DVB) microspheres prepared in this study were firstly covalently coated with dextran through a three-step method. The dextran was firstly adsorbed onto the microspheres and then covalently bound to the PGMA-DVB microsphere through ether bonds which were formed by hydroxyl group reacting with epoxy group at the presence of 4-(Dimethylamino) pyridine. Finally, the coating dextran layer was crosslinked by ethylene glycol diglycidyl ether to form the continuous network coating. The coated microspheres were characterized by Fourier transform infrared spectra, scanning electron microscope, mercury porosimetry measurements, laser scanning confocal microscope, and protein adsorption experiments. Results showed that PGMA-DVB microspheres coated with dextran successfully maintained the macroporous structure and high permeability. The backpressure was only 1.69 MPa at a high flow rate of 2891 cm/h. Consequently, the hydrophilicity and biocompatibility of modified microspheres were greatly improved, and the contact angle decreased from 184 Degree-Sign to 13 Degree-Sign , and nonspecific adsorption of proteins was decreased to little or none. The clad dextran coating with large amounts of hydroxyl group was easily derived to be various functional groups. The derived media have great potential applications in rapid protein chromatography. - Highlights: Black-Right-Pointing-Pointer Macroporous PGMA-DVB microspheres were covalently coated with dextran. Black-Right-Pointing-Pointer The hydrophilicity of the coated microspheres was significantly improved. Black-Right-Pointing-Pointer The irreversible adsorption of proteins was reduced to zero. Black-Right-Pointing-Pointer The coated microspheres can maintain the macropore structure. Black-Right-Pointing-Pointer The coated microspheres

  19. Covalently coating dextran on macroporous polyglycidyl methacrylate microsphere enabled rapid protein chromatographic separation

    International Nuclear Information System (INIS)

    Zhang, Rongyue; Li, Qiang; Li, Juan; Zhou, Weiqing; Ye, Peili; Gao, Yang; Ma, Guanghui; Su, Zhiguo

    2012-01-01

    Protein denaturation and nonspecific adsorption on polymer media as a chromatographic support have been a problem which needs to be overcome. Macroporous poly(glycidyl methacrylate–divinylbezene) (PGMA–DVB) microspheres prepared in this study were firstly covalently coated with dextran through a three-step method. The dextran was firstly adsorbed onto the microspheres and then covalently bound to the PGMA–DVB microsphere through ether bonds which were formed by hydroxyl group reacting with epoxy group at the presence of 4-(Dimethylamino) pyridine. Finally, the coating dextran layer was crosslinked by ethylene glycol diglycidyl ether to form the continuous network coating. The coated microspheres were characterized by Fourier transform infrared spectra, scanning electron microscope, mercury porosimetry measurements, laser scanning confocal microscope, and protein adsorption experiments. Results showed that PGMA–DVB microspheres coated with dextran successfully maintained the macroporous structure and high permeability. The backpressure was only 1.69 MPa at a high flow rate of 2891 cm/h. Consequently, the hydrophilicity and biocompatibility of modified microspheres were greatly improved, and the contact angle decreased from 184° to 13°, and nonspecific adsorption of proteins was decreased to little or none. The clad dextran coating with large amounts of hydroxyl group was easily derived to be various functional groups. The derived media have great potential applications in rapid protein chromatography. - Highlights: ► Macroporous PGMA–DVB microspheres were covalently coated with dextran. ► The hydrophilicity of the coated microspheres was significantly improved. ► The irreversible adsorption of proteins was reduced to zero. ► The coated microspheres can maintain the macropore structure. ► The coated microspheres were applied to rapid protein separation.

  20. Characteristics of immobilized aminoacylase from Aspergillus oryzae on macroporous copolymers.

    Science.gov (United States)

    He, B L; Jiang, P; Qiu, Y B

    1990-01-01

    Aminoacylase from Aspergillus oryzae was adsorbed on functionallized macroporous copolymers where the enzyme showed excellent catalyzing activity and operation stability. Various factors which effect the activity of the immobilized aminoacylase such as temperature, pH and ionic strength were investigated. The continuous operation of the enzyme immobilized on macroporous copolymers was compared with that of the enzyme immobilized on DEAE-Sephadex.

  1. Meta-analysis on Macropore Flow Velocity in Soils

    Science.gov (United States)

    Liu, D.; Gao, M.; Li, H. Y.; Chen, X.; Leung, L. R.

    2017-12-01

    Macropore flow is ubiquitous in the soils and an important hydrologic process that is not well explained using traditional hydrologic theories. Macropore Flow Velocity (MFV) is an important parameter used to describe macropore flow and quantify its effects on runoff generation and solute transport. However, the dominant factors controlling MFV are still poorly understood and the typical ranges of MFV measured at the field are not defined clearly. To address these issues, we conducted a meta-analysis based on a database created from 246 experiments on MFV collected from 76 journal articles. For a fair comparison, a conceptually unified definition of MFV is introduced to convert the MFV measured with different approaches and at various scales including soil core, field, trench or hillslope scales. The potential controlling factors of MFV considered include scale, travel distance, hydrologic conditions, site factors, macropore morphologies, soil texture, and land use. The results show that MFV is about 2 3 orders of magnitude larger than the corresponding values of saturated hydraulic conductivity. MFV is much larger at the trench and hillslope scale than at the field profile and soil core scales and shows a significant positive correlation with the travel distance. Generally, higher irrigation intensity tends to trigger faster MFV, especially at field profile scale, where MFV and irrigation intensity have significant positive correlation. At the trench and hillslope scale, the presence of large macropores (diameter>10 mm) is a key factor determining MFV. The geometric mean of MFV for sites with large macropores was found to be about 8 times larger than those without large macropores. For sites with large macropores, MFV increases with the macropore diameter. However, no noticeable difference in MFV has been observed among different soil texture and land use. Comparing the existing equations to describe MFV, the Poiseuille equation significantly overestimated the

  2. High energy density supercapacitors using macroporous kitchen sponges

    KAUST Repository

    Chen, Wei; Baby, Rakhi Raghavan; Alshareef, Husam N.

    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

  3. 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...

  4. Thermochemical stability of Soviet macroporous sulfonated cation-exchangers

    Energy Technology Data Exchange (ETDEWEB)

    Rukhlyada, N.N.; Plotnikova, V.P.; Roginskaya, B.S.; Znamenskii, Yu.P.; Zavodovskaya, A.S.; Dobrova, E.I.

    1988-10-20

    The purpose of this work was to study the influence of macroporosity on the thermochemical stability of sulfonated cation-exchangers. The investigations were carried out on commercial macroporous sulfonated cation-exchangers based on styrene-divinylbenzene copolymers. Study of the thermochemical stability of macroporous sulfonated cation-exchangers in dilute hydrogen peroxide solutions showed that the type of macroporosity has virtually no influence on their stability. The determining factor in thermal stability of macroporous cation-exchangers, as of the gel type, is the degree of cross-linking of the polymer matrix. The capacity loss of macroporous cation-exchangers during oxidative thermolysis is caused by destruction of the macromolecular skeleton and elution of fragments of polar chains containing sulfo groups into the solution.

  5. Soft-Template Construction of 3D Macroporous Polypyrrole Scaffolds.

    Science.gov (United States)

    Liu, Shaohua; Wang, Faxing; Dong, Renhao; Zhang, Tao; Zhang, Jian; Zheng, Zhikun; Mai, Yiyong; Feng, Xinliang

    2017-04-01

    A bottom-up approach toward 3D hierarchical macroporous polypyrrole aerogels is demonstrated via soft template-directed synthesis and self-assembly of ultrathin polypyrrole nanosheets in solution, which present interconnected macropores, ultrathin walls, and large specific surface areas, thereby exhibiting a high capacity, satisfactory rate capability, and excellent cycling stability for Na-ion storage. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Probing the structural dependence of carbon space lengths of poly(N-hydroxyalkyl acrylamide)-based brushes on antifouling performance.

    Science.gov (United States)

    Yang, Jintao; Zhang, Mingzhen; Chen, Hong; Chang, Yung; Chen, Zhan; Zheng, Jie

    2014-08-11

    Numerous biocompatible antifouling polymers have been developed for a wide variety of fundamental and practical applications in drug delivery, biosensors, marine coatings, and many other areas. Several antifouling mechanisms have been proposed, but the exact relationship among molecular structure, surface hydration property, and antifouling performance of antifouling polymers still remains elusive. Here this work strives to provide a better understanding of the structure-property relationship of poly(N-hydroxyalkyl acrylamide)-based materials. We have designed, synthesized, and characterized a series of polyHAAA brushes of various carbon spacer lengths (CSLs), that is, poly(N-hydroxymethyl acrylamide) (polyHMAA), poly(N-(2-hydroxyethyl)acrylamide) (polyHEAA), poly(N-(3-hydroxypropyl)acrylamide) (polyHPAA), and poly(N-(5-hydroxypentyl)acrylamide) (polyHPenAA), to study the structural dependence of CSLs on their antifouling performance. HMAA, HEAA, HPAA, and HPenAA monomers contained one, two, three, and five methylene groups between hydroxyl and amide groups, while the other groups in polymer backbones were the same as each other. The relation of such small structural differences of polymer brushes to their surface hydration and antifouling performance was studied by combined experimental and computational methods including surface plasmon resonance sensors, sum frequency generation (SFG) vibrational spectroscopy, cell adhesion assay, and molecular simulations. Antifouling results showed that all polyHAAA-based brushes were highly surface resistant to protein adsorption from single protein solutions, undiluted blood serum and plasma, as well as cell adhesion up to 7 days. In particular, polyHMAA and polyHEAA with the shorter CSLs exhibited higher surface hydration and better antifouling ability than polyHPMA and polyHPenAA. SFG and molecular simulations further revealed that the variation of CSLs changed the ratio of hydrophobicity/hydrophilicity of polymers

  7. Effects of macropores on groundwater flow and transport of radionuclides

    International Nuclear Information System (INIS)

    Huff, D.D.; DeAngelis, D.L.; Yeh, G.T.

    1983-01-01

    In humid environments, recent findings have shown that an important component of runoff and associated solute moves rapidly through large continuous voids. Thus, consideration of radionuclide transport in subsurface flow is incomplete without explicit treatment of continuous macropores and interaction between macropore flow and the soil matrix. A computer model, FRACPORT, that simulates the transport of a solute through a fractured porous matrix has been developed. The model employs the Integrated Compartment Method and uses the approach of dividing the porous media into compartments comprising fractures or porous material. The fracture region and a small portion of the porous matrix are simulated using a shorter time step than for the remaining porous matrix. This allows substantial savings in computational time. The model should be useful for analyses of generic problems associated with water and radionuclide transport in macropore systems at shallow-land disposal sites in humid environments. 14 references, 6 figures, 1 table

  8. Low-cost removal of organic pollutants with nickel nanoparticle loaded ordered macroporous hydrogel as high performance catalyst

    Energy Technology Data Exchange (ETDEWEB)

    Tang, Mingyi, E-mail: tmyi@tjcu.edu.cn [Department of Applied Chemistry, School of Science, Tianjin University of Commerce, Tianjin 300134 (China); Huang, Guanbo, E-mail: gbhuang2007@hotmail.com [Department of Chemistry, School of Science, Tianjin University, Tianjin 300072 (China); Zhang, Sai [Department of Applied Chemistry, School of Science, Tianjin University of Commerce, Tianjin 300134 (China); Liu, Yue [Department of Chemistry, School of Science, Tianjin University, Tianjin 300072 (China); Li, Xianxian [Department of Applied Chemistry, School of Science, Tianjin University of Commerce, Tianjin 300134 (China); Wang, Xingrui [Department of Chemistry, School of Science, Tianjin University, Tianjin 300072 (China); Pang, Xiaobo [Department of Applied Chemistry, School of Science, Tianjin University of Commerce, Tianjin 300134 (China); Qiu, Haixia, E-mail: qhx@tju.edu.cn [Department of Chemistry, School of Science, Tianjin University, Tianjin 300072 (China)

    2014-06-01

    A facile route for the in situ preparation of catalytically active Ni nanoparticles (NPs) in ordered macroporous hydrogel (OMH) has been developed. The hydrogel was fabricated based on polystyrene colloid template. The electronegativity of amide and carboxyl groups on the poly(acrylamide-co-acryl acid) chains of the hydrogel caused strong binding of Ni{sup 2+} ions which made them distribute uniformly inside the hydrogel. When immersed in NaBH{sub 4} aqueous solution, the Ni{sup 2+} ions on the hydrogel were reduced to Ni NPs. The resultant Ni NPs loaded OMH showed good catalytic activity for the reduction of a common organic pollutant, 4-nitrophenol, with NaBH{sub 4}. A kinetic study of the catalytic reaction was carried out. The rate constant per unit weight could reach 0.53 s{sup −1} g{sup −1}, which is much better than many common hydrogel loaded nickel catalysts. Moreover, the current catalyst can be easily separated and recovered with stable catalytic activity. - Highlights: • A new poly(acrylamide-co-acryl acid) hydrogel with ordered macropores. • A simple in situ fabrication of nickel nanoparticles under mild conditions. • High-performance heterogeneous catalyst for removal of nitrophenol from water. • Good recyclability of catalyst without any complicated regeneration process.

  9. Low-cost removal of organic pollutants with nickel nanoparticle loaded ordered macroporous hydrogel as high performance catalyst

    International Nuclear Information System (INIS)

    Tang, Mingyi; Huang, Guanbo; Zhang, Sai; Liu, Yue; Li, Xianxian; Wang, Xingrui; Pang, Xiaobo; Qiu, Haixia

    2014-01-01

    A facile route for the in situ preparation of catalytically active Ni nanoparticles (NPs) in ordered macroporous hydrogel (OMH) has been developed. The hydrogel was fabricated based on polystyrene colloid template. The electronegativity of amide and carboxyl groups on the poly(acrylamide-co-acryl acid) chains of the hydrogel caused strong binding of Ni 2+ ions which made them distribute uniformly inside the hydrogel. When immersed in NaBH 4 aqueous solution, the Ni 2+ ions on the hydrogel were reduced to Ni NPs. The resultant Ni NPs loaded OMH showed good catalytic activity for the reduction of a common organic pollutant, 4-nitrophenol, with NaBH 4 . A kinetic study of the catalytic reaction was carried out. The rate constant per unit weight could reach 0.53 s −1  g −1 , which is much better than many common hydrogel loaded nickel catalysts. Moreover, the current catalyst can be easily separated and recovered with stable catalytic activity. - Highlights: • A new poly(acrylamide-co-acryl acid) hydrogel with ordered macropores. • A simple in situ fabrication of nickel nanoparticles under mild conditions. • High-performance heterogeneous catalyst for removal of nitrophenol from water. • Good recyclability of catalyst without any complicated regeneration process

  10. Macropores and earthworm species affected by agronomic intensification

    DEFF Research Database (Denmark)

    Krogh, Paul Henning; Pérès, Guénola

    project EcoFINDERS we investigated the relationsship between earthworm biodiversity, macropores and three agricultural landuse types. A field campaign was conducted in October-November 2011. Earthworm burrow distribution was quantified at 10, 20, 30, 50 and 100 20 cm horizontal layer intervals down...... the soil profile to 1 meter depth and correlated with the earthworm community consisting of 12 species dominated by the endogeics Aporrectodea caliginosa and Aporrectodea chlorotica and the anecics Aporrectodea longa and Lumbricus centralis. Medium-small macropores in the ploughing layer with diameters (Ø...

  11. Macroporous silica–alumina composites with mesoporous walls

    Indian Academy of Sciences (India)

    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 ...

  12. 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.

  13. High-Surface-Area, Emulsion-Templated Carbon Foams by Activation of polyHIPEs Derived from Pickering Emulsions

    Directory of Open Access Journals (Sweden)

    Robert T. Woodward

    2016-09-01

    Full Text Available Carbon foams displaying hierarchical porosity and excellent surface areas of >1400 m2/g can be produced by the activation of macroporous poly(divinylbenzene. Poly(divinylbenzene was synthesized from the polymerization of the continuous, but minority, phase of a simple high internal phase Pickering emulsion. By the addition of KOH, chemical activation of the materials is induced during carbonization, producing Pickering-emulsion-templated carbon foams, or carboHIPEs, with tailorable macropore diameters and surface areas almost triple that of those previously reported. The retention of the customizable, macroporous open-cell structure of the poly(divinylbenzene precursor and the production of a large degree of microporosity during activation leads to tailorable carboHIPEs with excellent surface areas.

  14. Predicting macropores in space and time by earthworms and abiotic controls

    Science.gov (United States)

    Hohenbrink, Tobias Ludwig; Schneider, Anne-Kathrin; Zangerlé, Anne; Reck, Arne; Schröder, Boris; van Schaik, Loes

    2017-04-01

    Macropore flow increases infiltration and solute leaching. The macropore density and connectivity, and thereby the hydrological effectiveness, vary in space and time due to earthworms' burrowing activity and their ability to refill their burrows in order to survive drought periods. The aim of our study was to predict the spatiotemporal variability of macropore distributions by a set of potentially controlling abiotic variables and abundances of different earthworm species. We measured earthworm abundances and effective macropore distributions using tracer rainfall infiltration experiments in six measurement campaigns during one year at six field sites in Luxembourg. Hydrologically effective macropores were counted in three soil depths (3, 10, 30 cm) and distinguished into three diameter classes (6 mm). Earthworms were sampled and determined to species-level. In a generalized linear modelling framework, we related macropores to potential spatial and temporal controlling factors. Earthworm species such as Lumbricus terrestris and Aporrectodea longa, local abiotic site conditions (land use, TWI, slope), temporally varying weather conditions (temperature, humidity, precipitation) and soil moisture affected the number of effective macropores. Main controlling factors and explanatory power of the models (uncertainty and model performance) varied depending on the depth and diameter class of macropores. We present spatiotemporal predictions of macropore density by daily-resolved, one year time series of macropore numbers and maps of macropore distributions at specific dates in a small-scale catchment with 5 m resolution.

  15. Preparation of a poly(3'-azido-3'-deoxythymidine-co-propargyl methacrylate-co-pentaerythritol triacrylate) monolithic column by in situ polymerization and a click reaction for capillary liquid chromatography of small molecules and proteins.

    Science.gov (United States)

    Lin, Zian; Yu, Ruifang; Hu, Wenli; Zheng, Jiangnan; Tong, Ping; Zhao, Hongzhi; Cai, Zongwei

    2015-07-07

    Combining free radical polymerization with click chemistry via a copper-mediated azide/alkyne cycloaddition (CuAAC) reaction in a "one-pot" process, a facile approach was developed for the preparation of a poly(3'-azido-3'-deoxythymidine-co-propargyl methacrylate-co-pentaerythritol triacrylate) (AZT-co-PMA-co-PETA) monolithic column. The resulting poly(AZT-co-PMA-co-PETA) monolith showed a relatively homogeneous monolithic structure, good permeability and mechanical stability. Different ratios of monomers and porogens were used for optimizing the properties of a monolithic column. A series of alkylbenzenes, amides, anilines, and benzoic acids were used to evaluate the chromatographic properties of the polymer monolith in terms of hydrophobic, hydrophilic and cation-exchange interactions, and the results showed that the poly(AZT-co-PMA-co-PETA) monolith exhibited more flexible adjustment in chromatographic selectivity than that of the parent poly(PMA-co-PETA) and AZT-modified poly(PMA-co-PETA) monoliths. Column efficiencies for toluene, DMF, and formamide with 35,000-48,000 theoretical plates per m could be obtained at a linear velocity of 0.17 mm s(-1). The run-to-run, column-to-column, and batch-to-batch repeatabilities of the retention factors were less than 4.2%. In addition, the proposed monolith was also applied to efficient separation of sulfonamides, nucleobases and nucleosides, anesthetics and proteins for demonstrating its potential.

  16. An internal magnetic field strategy to reuse pulverized active materials for high performance: a magnetic three-dimensional ordered macroporous TiO2/CoPt/α-Fe2O3 nanocomposite anode.

    Science.gov (United States)

    Tang, Yiping; Hong, Liang; Li, Jiquan; Hou, Guangya; Cao, Huazhen; Wu, Liankui; Zheng, Guoqu; Wu, Qingliu

    2017-05-09

    A ferromagnetic three-dimensional ordered macroporous TiO 2 /CoPt/α-Fe 2 O 3 (3DOMTCF) nanocomposite was synthesized via a sol-gel approach templated by poly(methyl methacrylate) (PMMA) microspheres. After magnetization, it exhibited an extremely high reversible capacity and a long cycle life, which were ascribed to the internal magnetic field for reusing pulverized active materials and its unique structure.

  17. Starch and chitosan oligosaccharides as interpenetrating phases in poly(N-isopropylacrylamide) injectable gels

    Energy Technology Data Exchange (ETDEWEB)

    Vieira, Jacquelin N.; Posada, James J. [Chemistry Department, B" 5IDA Research Group, Universidad Simón Bolívar, Caracas (Venezuela, Bolivarian Republic of); Rezende, Rodrigo A. [Divisão de Tecnologias Tridimensionais–Centro de Tecnologia da Informação Renato Archer, Campinas, SP (Brazil); Sabino, Marcos A., E-mail: msabino@usb.ve [Chemistry Department, B" 5IDA Research Group, Universidad Simón Bolívar, Caracas (Venezuela, Bolivarian Republic of); Divisão de Tecnologias Tridimensionais–Centro de Tecnologia da Informação Renato Archer, Campinas, SP (Brazil)

    2014-04-01

    Thermosensitive interpenetrating gels were prepared by physically blending poly(N-isopropylacrylamide) (PNIPA) as the matrix and the following polysaccharides as interpenetrating phases: chitosan oligosaccharides (identified as QNAD and QNED) and soluble starch (STARCH). The molecular weight of the dispersed phase, the free water/bound water ratio and the thermosensitivity (transition temperature: LCST) of the gels were determined. It was found that these gels are pseudoplastic and that their viscosity depends on the molecular weight of the dispersed phase. LCST transition occurred around 35–37 °C. The morphology of the porosity of the freeze-dried samples was studied by Scanning Electron Microscopy (SEM). An in vitro test of cell hemolysis on blood agar showed that these gels are noncytotoxic. According to the results obtained, these interpenetrating gels show characteristics of an injectable material, and have a transition LCST at body temperature, which reinforces their potential to be used in the surgical field and as scaffolds for tissue engineering. - Highlights: • Physical blends were prepared to obtain thermosensitive gels PNIPA/polysaccharides. • Rheological test allowed verifying the injectability of the gels. • Gels showed a LCST ∼ 37 °C, which makes them interesting for biomedical applications. • Porosity is a function of hydrophobicity/hydrophilicity/molecular weight of phases. • The PNIPA/starch gel showed better morphology as scaffold for tissue engineering.

  18. Surface modified nano-hydroxyapatite/poly(lactide acid) composite and its osteocyte compatibility

    International Nuclear Information System (INIS)

    Diao Huaxin; Si Yunfeng; Zhu Aiping; Ji Lijun; Shi Hongchan

    2012-01-01

    In this study, melt blending was used to fabricate poly(lactic acid) (PLA)/ hydroxyapatite (HA) nanocomposites. Surface modifying HA nanoparticles (mHA) with dodecyl alcohol through esterification reaction could effectively improve the dispersibility of HA nanoparticles in PLA matrix and the interfacial interactions between PLA and HA nanoparticles, as revealed by field emission scanning electron microscopy (FESEM), rheology analysis, and dynamic mechanical thermal analysis (DMTA). mHA/PLA nanocomposite film demonstrated better cartilage cell attachment, spreading and proliferation than that of PLA and HA/PLA film. The good cytocompatibility could be due to the good dispersibility of the osteoinductive HA nanoparticles, good interfacial interactions between PLA and HA nanoparticles, and balanced hydrophobic/hydrophilic property. This newly developed mHA/PLA nanocomposites may be considered for bone tissue engineering applications. - Highlights: ► Dodecyl alcohol modifies HA nanoparticles via esterification reaction. ► The modified HA results in good dispersibility in PLA matrix. ► The interfacial interactions are improved because of the modified HA. ► The addition of HA and mHA results in good cell affinity and biocompatibility.

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

    International Nuclear Information System (INIS)

    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

  20. Preparation of macroporous zirconia monoliths from ionic precursors via an epoxide-mediated sol-gel process accompanied by phase separation

    International Nuclear Information System (INIS)

    Guo, Xingzhong; Song, Jie; Lvlin, Yixiu; Yang, Hui; Nakanishi, Kazuki; Kanamori, Kazuyoshi

    2015-01-01

    Monolithic macroporous zirconia (ZrO 2 ) derived from ionic precursors has been successfully fabricated via the epoxide-mediated sol-gel route accompanied by phase separation in the presence of propylene oxide (PO) and poly(ethylene oxide) (PEO). The addition of PO used as an acid scavenger mediates the gelation, whereas PEO enhances the polymerization-induced phase separation. The appropriate choice of the starting compositions allows the production of a macroporous zirconia monolith with a porosity of 52.9% and a Brunauer–Emmett–Teller (BET) surface area of 171.9 m 2 · g −1 . The resultant dried gel is amorphous, whereas tetragonal ZrO 2 and monoclinic ZrO 2 are precipitated at 400 and 600 °C, respectively, without spoiling the macroporous morphology. After solvothermal treatment with an ethanol solution of ammonia, tetragonal ZrO 2 monoliths with smooth skeletons and well-defined mesopores can be obtained, and the BET surface area is enhanced to 583.8 m 2 · g −1 . (paper)

  1. 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

    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...... to macropore sediment transport. Simulated tile drain discharge, sediment and pesticide loads are calibrated against data from intensively monitored tile-drained fields and streams in Denmark....

  2. Functionalization of 2D macroporous silicon under the high-pressure oxidation

    Science.gov (United States)

    Karachevtseva, L.; Kartel, M.; Kladko, V.; Gudymenko, O.; Bo, Wang; Bratus, V.; Lytvynenko, O.; Onyshchenko, V.; Stronska, O.

    2018-03-01

    Addition functionalization after high-pressure oxidation of 2D macroporous silicon structures is evaluated. X-ray diffractometry indicates formation of orthorhombic SiO2 phase on macroporous silicon at oxide thickness of 800-1200 nm due to cylindrical symmetry of macropores and high thermal expansion coefficient of SiO2. Pb center concentration grows with the splitting energy of LO- and TO-phonons and SiO2 thickness in oxidized macroporous silicon structures. This increase EPR signal amplitude and GHz radiation absorption and is promising for development of high-frequency devices and electronically controlled elements.

  3. Application of polymeric macroporous supports for temperature-responsive chromatography of pharmaceuticals.

    Science.gov (United States)

    Lamprou, Alexandros; Gavriilidou, Agni-Faviola-Mika; Storti, Giuseppe; Soos, Miroslav; Morbidelli, Massimo

    2015-08-14

    A macroporous particulate support prepared previously by reactive gelation under shear and functionalized with poly(N-isopropylacrylamide), PNIPAM, brushes of variable length is applied for temperature-responsive chromatography, whereby temperature modulates hydrophobic interactions. Several different analytes, including small pharmaceuticals, peptides, proteins and monoclonal antibodies are employed. Contrary to the most commonly observed behavior in conventional chromatography, increasing retention is observed at elevated temperatures. Peak broadening is quantified using the peak standard deviation, which depends on both the polymer chain conformation and analyte adsorptivity. The favorable effect of grafted polymer thickness on retention becomes progressively less pronounced for thicker grafted PNIPAM layers. The effect of eluent composition on solute-sorbent interactions was investigated by introducing NaCl, methanol, dioxane and by varying the pH. Salt or organic solvent addition affects apart from the analytes solution properties, the hydrophobicity of the stationary phase itself. Frontal analyses performed at different temperatures to determine dynamic binding capacities, indicate small mass transfer resistances imposed by this novel packing material. Copyright © 2015 Elsevier B.V. All rights reserved.

  4. Nonenzymatic free-cholesterol detection via a modified highly sensitive macroporous gold electrode with platinum nanoparticles.

    Science.gov (United States)

    Lee, Yi-Jae; Park, Jae-Yeong

    2010-12-15

    A sensitive macroporous Au electrode with a highly rough surface obtained through the use of with Pt nanoparticles (macroporous Au-/nPts) is reported. It has been designed for nonenzymatic free-cholesterol biosensor applications. A macroporous Au-/nPts electrode was fabricated by electroplating Pt nanoparticles onto a coral-like shaped macroporous Au electrode structure. The macroporous Au-/nPts electrode was physically characterized by field emission scanning electron microscopy (FESEM). It was confirmed that the Pt nanoparticles were well deposited on the surface of the macroporous Au electrode. The porosity and window pore size of the macroporous Au electrode were 50% and 100-300 nm, respectively. The electroplated Pt nanoparticle size was approximately 10-20 nm. Electrochemical experiments showed that the macroporous Au-/nPts exhibited a much larger surface activation area (roughness factor (RF)=2024.7) than the macroporous Au electrode (RF=46.07). The macroporous Au-/nPts also presented a much stronger electrocatalytic activity towards cholesterol oxidation than does the macroporous Au electrode. At 0.2 V, the electrode responded linearly up to a 5 mM cholesterol concentration in a neutral media, with a detection limit of 0.015 mM and detection sensitivity of 226.2 μA mM(-1) cm(-2). Meanwhile, interfering species such as ascorbic acid (AA), acetaminophen (AP), and uric acid (UA), were effectively avoided. This novel nonenzymatic detection electrode has strong applications as an electrochemically based cholesterol biosensor. Copyright © 2010 Elsevier B.V. All rights reserved.

  5. In vitro and in vivo study to the biocompatibility and biodegradation of hydroxyapatite/poly(vinyl alcohol)/gelatin composite.

    NARCIS (Netherlands)

    Wang, M.; Li, Y.; Wu, J.; Xu, F.; Zuo, Y.; Jansen, J.A.

    2008-01-01

    A novel porous composite material composed of hydroxyapatite, poly(vinyl alcohol) (PVA), and gelatin (Gel) was fabricated by emulsification. Scanning electron microscopy showed that the material had a well-interconnected porous structure including many macropores (100-500 microm) and micropores

  6. Modified APEX model for Simulating Macropore Phosphorus Contributions to Tile Drains.

    Science.gov (United States)

    Ford, William I; King, Kevin W; Williams, Mark R; Confesor, Remegio B

    2017-11-01

    The contribution of macropore flow to phosphorus (P) loadings in tile-drained agricultural landscapes remains poorly understood at the field scale, despite the recognized deleterious impacts of contaminant transport via macropore pathways. A new subroutine that couples existing matrix-excess and matrix-desiccation macropore flow theory and a modified P routine is implemented in the Agricultural Policy Environmental eXtender (APEX) model. The original and modified formulation were applied and evaluated for a case study in a poorly drained field in Western Ohio with 31 months of surface and subsurface monitoring data. Results highlighted that a macropore subroutine in APEX improved edge-of-field discharge calibration and validation for both tile and total discharge from satisfactory and good, respectively, to very good and improved dissolved reactive P load calibration and validation statistics for tile P loads from unsatisfactory to very good. Output from the calibrated macropore simulations suggested median annual matrix-desiccation macropore flow contributions of 48% and P load contributions of 43%, with the majority of loading occurring in winter and spring. While somewhat counterintuitive, the prominence of matrix-desiccation macropore flow during seasons with less cracking reflects the importance of coupled development of macropore pathways and adequate supply of the macropore flow source. The innovative features of the model allow for assessments of annual macropore P contributions to tile drainage and has the potential to inform P site assessment tools. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

  7. Macroporous Hydrogel Scaffolds for Three-Dimensional Cell Culture and Tissue Engineering.

    Science.gov (United States)

    Fan, Changjiang; Wang, Dong-An

    2017-10-01

    Hydrogels have been promising candidate scaffolds for cell delivery and tissue engineering due to their tissue-like physical properties and capability for homogeneous cell loading. However, the encapsulated cells are generally entrapped and constrained in the submicron- or nanosized gel networks, seriously limiting cell growth and tissue formation. Meanwhile, the spatially confined settlement inhibits attachment and spreading of anchorage-dependent cells, leading to their apoptosis. In recent years, macroporous hydrogels have attracted increasing attention in use as cell delivery vehicles and tissue engineering scaffolds. The introduction of macropores within gel scaffolds not only improves their permeability for better nutrient transport but also creates space/interface for cell adhesion, proliferation, and extracellular matrix deposition. Herein, we will first review the development of macroporous gel scaffolds and outline the impact of macropores on cell behaviors. In the first part, the advantages and challenges of hydrogels as three-dimensional (3D) cell culture scaffolds will be described. In the second part, the fabrication of various macroporous hydrogels will be presented. Third, the enhancement of cell activities within macroporous gel scaffolds will be discussed. Finally, several crucial factors that are envisaged to propel the improvement of macroporous gel scaffolds are proposed for 3D cell culture and tissue engineering.

  8. 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

  9. Drug delivery properties of macroporous polystyrene solid foams.

    Science.gov (United States)

    Canal, Cristina; Aparicio, Rosa Maria; Vilchez, Alejandro; Esquena, Jordi; García-Celma, Maria José

    2012-01-01

    Polymeric porous foams have been evaluated as possible new pharmaceutical dosage forms. These materials were obtained by polymerization in the continuous phase of highly concentrated emulsions prepared by the phase inversion temperature method. Their porosity, specific surface and surface topography were characterized, and the incorporation and release of active principles was studied using ketoprofen as model lipophilic molecule. Solid foams with very high pore volume, mainly inside macropores, were obtained by this method. The pore morphology of the materials was characterized, and very rough topography was observed, which contributed to their nearly superhydrophobic properties. These solid foams could be used as delivery systems for active principles with pharmaceutical interest, and in the present work ketoprofen was used as a model lipophilic molecule. Drug incorporation and release was studied from solid foam disks, using different concentrations of the loading solutions, achieving a delayed release with short lag-time.

  10. Bias-assisted KOH etching of macroporous silicon membranes

    International Nuclear Information System (INIS)

    Mathwig, K; Geilhufe, M; Müller, F; Gösele, U

    2011-01-01

    This paper presents an improved technique to fabricate porous membranes from macroporous silicon as a starting material. A crucial step in the fabrication process is the dissolution of silicon from the backside of the porous wafer by aqueous potassium hydroxide to open up the pores. We improved this step by biasing the silicon wafer electrically against the KOH. By monitoring the current–time characteristics a good control of the process is achieved and the yield is improved. Also, the etching can be stopped instantaneously and automatically by short-circuiting Si and KOH. Moreover, the bias-assisted etching allows for the controlled fabrication of silicon dioxide tube arrays when the silicon pore walls are oxidized and inverted pores are released.

  11. Design of pore size of macroporous ceramic substrates

    International Nuclear Information System (INIS)

    Szewald, O.; Kotsis, I.

    2000-01-01

    A method has been developed for the design of macro-porous ceramic substrates. Based on geometrical and regression models detailed technology was worked out for producing these 100% open porous filters, which were made using quasi homo-disperse fractions of corundum of diameters of several tens and hundreds microns and glassy binding material. Axial pressing was used as a forming process. Pore networks with size distribution that can be defined by a curve having one maximum were provided applying the above technology. Based on geometrical considerations and measurements it was proved that these maximums are at characteristic pore sizes that depend only on characteristic size of the original grain fractions and on the extent of the axial forming pressure. Copyright (2000) AD-TECH - International Foundation for the Advancement of Technology Ltd

  12. 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.

  13. 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

    characteristics on soil hydraulic functions has rarely been studied. With the objective of studying the links between these parameters we quantified macropore characteristics of intact soil columns (19 cm diameter x 20 cm high) from two agricultural field sites (Silstrup and Faardrup) in Denmark using coarse...... 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...

  14. Macroporous 'bubble' graphene film via template-directed ordered-assembly for high rate supercapacitors.

    Science.gov (United States)

    Chen, Cheng-Meng; Zhang, Qiang; Huang, Chun-Hsien; Zhao, Xiao-Chen; Zhang, Bing-Sen; Kong, Qing-Qiang; Wang, Mao-Zhang; Yang, Yong-Gang; Cai, Rong; Sheng Su, Dang

    2012-07-21

    A three-dimensional bubble graphene film, with controllable and uniform macropores and tailorable microstructure, was fabricated by a facile hard templating strategy and exhibit extraordinary electrochemical capacitance with high rate capability (1.0 V s(-1)).

  15. 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

    of macropore structure and hydraulic efficiency, using image analysis and tension infiltration, and of soil water content, level of groundwater table, and chloride content of soil water within the soil profile yielded insights into small-scale processes and their associated variability. Macropore how...... 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...... for continuous solute exchange with the macropores. An average field-determined active macroporosity constituted 0.2% of the total porosity, or approximately 10% of the total macroporosity. (C) 1998 Elsevier Science B.V. All rights reserved....

  16. [Studies on the process of Herba Clinopodii saponins purified with macroporous adsorption resin].

    Science.gov (United States)

    Zhang, Yi; Yan, Dan; Han, Yumei

    2005-10-01

    To study the technological parameters of the purification process of saponins with macroporous adsorption resin. The adsorptive characteristics and elutive parameters of the process were studied by taking the elutive and purified ratio of saponins as markers. 11.4 ml of the extraction of Herba Clinopodii (crude drugs 0.2 g/ml) was purified with a column of macroporous adsorption resin (phi15 mm x H90 mm, dry weight 2.5 g) and washed with 3BV of distilled water, then eluted with 3BV of 30% ethanol and 3BV of 70% ethanol. Most of saponins were collected in the 70% ethanol. With macroporous adsorption resin adsorbing and purifying,the elutive ratio of saponins is 86.8% and the purity reaches 153.2%. So this process of applying macroporous adsorption resin to adsorb and purify Saponins is feasible.

  17. Occurrence of the macropore nucleation centers in silicon as result of ion implantation

    CERN Document Server

    Astrova, E V

    2002-01-01

    Instead of commonly used V-shaped pits the possibility of application of ion implantation for formation of the regular pattern of macropore nucleation centers has been studied. It is shown that selective radiative damage or local conductivity type conversion are sufficient for generation of macropore nucleation in certain regions and passivation in other ones. Results obtained can be of interest both for practical application and for explanation of pore origin in silicon

  18. A new method to produce macroporous Mg-phosphate bone growth substitutes

    Energy Technology Data Exchange (ETDEWEB)

    Babaie, Elham, E-mail: Elham.Babaie@rockets.utoledo.edu [Department of Biomedical Engineering, University of Toledo, Toledo, OH 43606 (United States); Lin, Boren [Department of Biomedical Engineering, University of Toledo, Toledo, OH 43606 (United States); Bhaduri, Sarit B. [Department of Mechanical, Industrial and Manufacturing Engineering, University of Toledo, Toledo, OH 43606 (United States); Department of Surgery (Dentistry), University of Toledo, Toledo, OH 43614 (United States)

    2017-06-01

    This paper is a sequel to our previous effort in developing Mg-phosphate orthopedic cements using amorphous Mg-phosphate (AMP) as the precursor. In this paper, we report a new real-time in situ technique to create macroporous bone growth substitute (BGS). The method uses biodegradable Mg-particles as the porogen. As opposed to the conventional wisdom of providing corrosion protection layers to biodegradable Mg-alloys, the present method uses the fast corrosion kinetics of Mg to create macropores in real time during the setting of the cement. An aqueous solution of PVA was used as the setting solution. Using this technique, a macroporous cement containing up to 91% porosity is obtained, as determined by pycnometry. Due to formation of H{sub 2} gas bubbles from corrosion of Mg, the cement becomes macroporous. The pore sizes as big as 760 μm were observed. The results of SBF soaking indicated change in crystallinity as confirmed via scanning electron microscopy (SEM) and X-ray diffraction (XRD). Our in vitro cytocompatibility evaluation also revealed that the macroporous bone growth substitute composed of bobierrite is cytocompatible and can improve gene expression. - Highlights: • We report a new real time, in situ technique to fabricate macroporous bone grafts. • Self-corroding Mg granules act as porogens. • Compositions containing AMP and PVA self-set within a reasonable time. • The final bone graft substitute showed promising biocompatibility. • The results provide important information on the porosity content and bioactivity.

  19. Preparation of three-dimensionally ordered macroporous perovskite-type lanthanum-iron-oxide LaFeO3 with tunable pore diameters: High porosity and photonic property

    International Nuclear Information System (INIS)

    Sadakane, Masahiro; Horiuchi, Toshitaka; Kato, Nobuyasu; Sasaki, Keisuke; Ueda, Wataru

    2010-01-01

    Three-dimensionally ordered macroporous (3DOM) lanthanum-iron-oxide (LaFeO 3 ) with different pore diameters was prepared using a colloidal crystal of polymer spheres with different diameters as templates. Ethylene glycol-methanol mixed solution of metal nitrates was infiltrated into the void of the colloidal crystal template of a monodispersed poly(methyl methacrylate) (PMMA) sphere. Heating of this PMMA-metal salt-ethylene glycol composite produced the desired well-ordered 3DOM LaFeO 3 with a high pore fraction, which was confirmed by powder X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), mercury (Hg) porosimetry, and ultraviolet-visible (UV-vis) diffuse reflectance spectra. 3DOM LaFeO 3 with pore diameters of 281 and 321 nm shows opalescent colors because of photonic stop band properties. Catalytic activity of the 3DOM LaFeO 3 for combustion of carbon particles was enhanced by a potassium cation, which was involved from K 2 S 2 O 8 used as a polymerization initiator. - Graphical abstract: Well-ordered three-dimensionally ordered macroporous LaFeO 3 materials with pore sizes ranging from 127 to 321 nm were obtained in a high pore fraction.

  20. Cholesterol-imprinted macroporous monoliths: Preparation and characterization.

    Science.gov (United States)

    Stepanova, Mariia А; Kinziabulatova, Lilia R; Nikitina, Anna A; Korzhikova-Vlakh, Evgenia G; Tennikova, Tatiana B

    2017-11-01

    The development of sorbents for selective binding of cholesterol, which is a risk factor for cardiovascular disease, has a great importance for analytical science and medicine. In this work, two series of macroporous cholesterol-imprinted monolithic sorbents differing in the composition of functional monomers (methacrylic acid, butyl methacrylate, 2-hydroxyethyl methacrylate and ethylene dimethacrylate), amount of a template (4, 6 and 8 mol%) used for molecular imprinting, as well as mean pore size were synthesized by in situ free-radical process in stainless steel housing of 50 mm × 4.6 mm i.d. All prepared materials were characterized regarding to their hydrodynamic permeability and porous properties, as well as examined by BET and SEM methods. Imprinting factors, apparent dynamic dissociation constants, the maximum binding capacity, the number of theoretical plates and the height equivalent to a theoretical palate of MIP monoliths at different mobile phase flow rates were determined. The separation of a mixture of structural analogues, namely, cholesterol and prednisolone, was demonstrated. Additionally, the possibility of using the developed monoliths for cholesterol solid-phase extraction from simulated biological solution was shown. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. 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.

  2. Spatial structure and scaling of macropores in hydrological process at small catchment scale

    Science.gov (United States)

    Silasari, Rasmiaditya; Broer, Martine; Blöschl, Günter

    2013-04-01

    During rainfall events, the formation of overland flow can occur under the circumstances of saturation excess and/or infiltration excess. These conditions are affected by the soil moisture state which represents the soil water content in micropores and macropores. Macropores act as pathway for the preferential flows and have been widely studied locally. However, very little is known about their spatial structure and conductivity of macropores and other flow characteristic at the catchment scale. This study will analyze these characteristics to better understand its importance in hydrological processes. The research will be conducted in Petzenkirchen Hydrological Open Air Laboratory (HOAL), a 64 ha catchment located 100 km west of Vienna. The land use is divided between arable land (87%), pasture (5%), forest (6%) and paved surfaces (2%). Video cameras will be installed on an agricultural field to monitor the overland flow pattern during rainfall events. A wireless soil moisture network is also installed within the monitored area. These field data will be combined to analyze the soil moisture state and the responding surface runoff occurrence. The variability of the macropores spatial structure of the observed area (field scale) then will be assessed based on the topography and soil data. Soil characteristics will be supported with laboratory experiments on soil matrix flow to obtain proper definitions of the spatial structure of macropores and its variability. A coupled physically based distributed model of surface and subsurface flow will be used to simulate the variability of macropores spatial structure and its effect on the flow behaviour. This model will be validated by simulating the observed rainfall events. Upscaling from field scale to catchment scale will be done to understand the effect of macropores variability on larger scales by applying spatial stochastic methods. The first phase in this study is the installation and monitoring configuration of video

  3. Preparation of epoxy-based macroporous monolithic columns for the fast and efficient immunofiltration of Staphylococcus aureus.

    Science.gov (United States)

    Ott, Sonja; Niessner, Reinhard; Seidel, Michael

    2011-08-01

    Macroporous epoxy-based monolithic columns were used for immunofiltration of bacteria. The prepared monolithic polymer support is hydrophilic and has large pore sizes of 21 μm without mesopores. A surface chemistry usually applied for immobilization of antibodies on glass slides is successfully transferred to monolithic columns. Step-by-step, the surface of the epoxy-based monolith is hydrolyzed, silanized, coated with poly(ethylene glycol diamine) and activated with the homobifunctional crosslinker di(N-succinimidyl)carbonate for immobilization of antibodies on the monolithic columns. The functionalization steps are characterized to ensure the coating of each monolayer. The prepared antibody-immobilized monolithic column is optimized for immunofiltration to enrich Staphylococcus aureus as an important food contaminant. Different kinds of geometries of monolithic columns, flow rates and elution buffers are tested with the goal to get high recoveries in the shortest enrichment time as possible. An effective capture of S. aureus was achieved at a flow rate of 7.0 mL/min with low backpressures of 20.1±5.4 mbar enabling a volumetric enrichment of 1000 within 145 min. The bacteria were quantified by flow cytometry using a double-labeling approach. After immunofiltration the sensitivity was significantly increased and a detection limit of the total system of 42 S. aureus/mL was reached. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Thickness-Dependent Bioelectrochemical and Energy Applications of Thickness-Controlled Meso-Macroporous Antimony-Doped Tin Oxide

    Directory of Open Access Journals (Sweden)

    Daniel Mieritz

    2018-04-01

    Full Text Available Coatings of hierarchically meso-macroporous antimony-doped tin oxide (ATO enable interfacing adsorbed species, such as biomacromolecules, with an electronic circuit. The coating thickness is a limiting factor for the surface coverage of adsorbates, that are electrochemically addressable. To overcome this challenge, a carbon black-based templating method was developed by studying the composition of the template system, and finding the right conditions for self-standing templates, preventing the reaction mixture from flowing out of the mask. The thicknesses of as-fabricated coatings were measured using stylus profilometry to establish a relationship between the mask thickness and the coating thickness. Cyclic voltammetry was performed on coatings with adsorbed cytochrome c to check whether the entire coating thickness was electrochemically addressable. Further, bacterial photosynthetic reaction centers were incorporated into the coatings, and photocurrent with respect to coating thickness was studied. The template mixture required enough of both carbon black and polymer, roughly 7% carbon black and 6% poly(ethylene glycol. Coatings were fabricated with thicknesses approaching 30 µm, and thickness was shown to be controllable up to at least 15 µm. Under the experimental conditions, photocurrent was found to increase linearly with the coating thickness, up to around 12 µm, above which were diminished gains.

  5. Coupling of Spinosad Fermentation and Separation Process via Two-Step Macroporous Resin Adsorption Method.

    Science.gov (United States)

    Zhao, Fanglong; Zhang, Chuanbo; Yin, Jing; Shen, Yueqi; Lu, Wenyu

    2015-08-01

    In this paper, a two-step resin adsorption technology was investigated for spinosad production and separation as follows: the first step resin addition into the fermentor at early cultivation period to decrease the timely product concentration in the broth; the second step of resin addition was used after fermentation to adsorb and extract the spinosad. Based on this, a two-step macroporous resin adsorption-membrane separation process for spinosad fermentation, separation, and purification was established. Spinosad concentration in 5-L fermentor increased by 14.45 % after adding 50 g/L macroporous at the beginning of fermentation. The established two-step macroporous resin adsorption-membrane separation process got the 95.43 % purity and 87 % yield for spinosad, which were both higher than that of the conventional crystallization of spinosad from aqueous phase that were 93.23 and 79.15 % separately. The two-step macroporous resin adsorption method has not only carried out the coupling of spinosad fermentation and separation but also increased spinosad productivity. In addition, the two-step macroporous resin adsorption-membrane separation process performs better in spinosad yield and purity.

  6. Direct Writing of Three-Dimensional Macroporous Photonic Crystals on Pressure-Responsive Shape Memory Polymers.

    Science.gov (United States)

    Fang, Yin; Ni, Yongliang; Leo, Sin-Yen; Wang, Bingchen; Basile, Vito; Taylor, Curtis; Jiang, Peng

    2015-10-28

    Here we report a single-step direct writing technology for making three-dimensional (3D) macroporous photonic crystal patterns on a new type of pressure-responsive shape memory polymer (SMP). This approach integrates two disparate fields that do not typically intersect: the well-established templating nanofabrication and shape memory materials. Periodic arrays of polymer macropores templated from self-assembled colloidal crystals are squeezed into disordered arrays in an unusual shape memory "cold" programming process. The recovery of the original macroporous photonic crystal lattices can be triggered by direct writing at ambient conditions using both macroscopic and nanoscopic tools, like a pencil or a nanoindenter. Interestingly, this shape memory disorder-order transition is reversible and the photonic crystal patterns can be erased and regenerated hundreds of times, promising the making of reconfigurable/rewritable nanooptical devices. Quantitative insights into the shape memory recovery of collapsed macropores induced by the lateral shear stresses in direct writing are gained through fundamental investigations on important process parameters, including the tip material, the critical pressure and writing speed for triggering the recovery of the deformed macropores, and the minimal feature size that can be directly written on the SMP membranes. Besides straightforward applications in photonic crystal devices, these smart mechanochromic SMPs that are sensitive to various mechanical stresses could render important technological applications ranging from chromogenic stress and impact sensors to rewritable high-density optical data storage media.

  7. 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.

  8. Representing macropore flow at the catchment scale: a comparative modeling study

    Science.gov (United States)

    Liu, D.; Li, H. Y.; Tian, F.; Leung, L. R.

    2017-12-01

    Macropore flow is an important hydrological process that generally enhances the soil infiltration capacity and velocity of subsurface water. Up till now, macropore flow is mostly simulated with high-resolution models. One possible drawback of this modeling approach is the difficulty to effectively represent the overall typology and connectivity of the macropore networks. We hypothesize that modeling macropore flow directly at the catchment scale may be complementary to the existing modeling strategy and offer some new insights. Tsinghua Representative Elementary Watershed model (THREW model) is a semi-distributed hydrology model, where the fundamental building blocks are representative elementary watersheds (REW) linked by the river channel network. In THREW, all the hydrological processes are described with constitutive relationships established directly at the REW level, i.e., catchment scale. In this study, the constitutive relationship of macropore flow drainage is established as part of THREW. The enhanced THREW model is then applied at two catchments with deep soils but distinct climates, the humid Asu catchment in the Amazon River basin, and the arid Wei catchment in the Yellow River basin. The Asu catchment has an area of 12.43km2 with mean annual precipitation of 2442mm. The larger Wei catchment has an area of 24800km2 but with mean annual precipitation of only 512mm. The rainfall-runoff processes are simulated at a hourly time step from 2002 to 2005 in the Asu catchment and from 2001 to 2012 in the Wei catchment. The role of macropore flow on the catchment hydrology will be analyzed comparatively over the Asu and Wei catchments against the observed streamflow, evapotranspiration and other auxiliary data.

  9. 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.

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

    International Nuclear Information System (INIS)

    Laranjeira, M.S.; Dias, A.G.; Santos, J.D.; Fernandes, M.H.

    2009-01-01

    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 μm. 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.

  11. Soil Susceptibility to Macropore Flow Across a Desert-Oasis Ecotone of the Hexi Corridor, Northwest China

    Science.gov (United States)

    Zhang, Yongyong; Zhao, Wenzhi; He, Jianhua; Fu, Li

    2018-02-01

    Macropore flow not only provides a fast pathway for water and solute transport and increases the risks of water and nutrient loss but also enhances soil aeration and groundwater recharge. However, macropore flow characteristics in irrigated oasis soils subject to continuous crop cultivation are poorly understood. This study was to investigate the effect of continuous cultivation on soil properties and macropore flow and to quantify the changes in macropore flow characteristics in an old oasis field (>50 years of cultivation, OOF), young oasis field (20 years, YOF), and adjacent uncultivated sandy area (0 year, USL) in Northwest China. Triplicate soil samples were collected from each site to investigate soil properties. Dye tracer experiments with also three replicates were conducted at each site. The degree of macropore flow (i.e., parameters of macropore flow) was highest at the OOF, intermediate at the YOF, and minimal at the USL. The macropore flow fraction (i.e., fraction of total infiltration flows through macropore flow pathways) at the OOF was 3.4 times greater than at the USL. The heterogeneous infiltration pattern at the OOF was dominated by macropore flow, while funnel flow was predominant at the USL. Long-term irrigation with silt-laden river water has increased silt + clay contents of the oasis soils. Irrigation and high-input crop cultivation also increased organic matter. These changes in soil properties contributed to the interaggregate voids formation. The conversion of native desert soils to irrigated croplands increases the degree of macropore flow, which might enhance groundwater recharge in the desert-oasis ecotone.

  12. Highly ordered three-dimensional macroporous carbon spheres for determination of heavy metal ions

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Yuxiao; Zhang, Jianming [Institute of Functional Nano and Soft Materials (FUNSOM) and Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices, Soochow University, Suzhou 215123 (China); Liu, Yang, E-mail: yangl@suda.edu.cn [Institute of Functional Nano and Soft Materials (FUNSOM) and Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices, Soochow University, Suzhou 215123 (China); Huang, Hui [Institute of Functional Nano and Soft Materials (FUNSOM) and Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices, Soochow University, Suzhou 215123 (China); Kang, Zhenhui, E-mail: zhkang@suda.edu.cn [Institute of Functional Nano and Soft Materials (FUNSOM) and Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices, Soochow University, Suzhou 215123 (China)

    2012-04-15

    Highlights: Black-Right-Pointing-Pointer Highly ordered three dimensional macroporous carbon spheres (MPCSs) were prepared. Black-Right-Pointing-Pointer MPCS was covalently modified by cysteine (MPCS-CO-Cys). Black-Right-Pointing-Pointer MPCS-CO-Cys was first time used in electrochemical detection of heavy metal ions. Black-Right-Pointing-Pointer Heavy metal ions such as Pb{sup 2+} and Cd{sup 2+} can be simultaneously determined. -- Abstract: An effective voltammetric method for detection of trace heavy metal ions using chemically modified highly ordered three dimensional macroporous carbon spheres electrode surfaces is described. The highly ordered three dimensional macroporous carbon spheres were prepared by carbonization of glucose in silica crystal bead template, followed by removal of the template. The highly ordered three dimensional macroporous carbon spheres were covalently modified by cysteine, an amino acid with high affinities towards some heavy metals. The materials were characterized by physical adsorption of nitrogen, scanning electron microscopy, and transmission electron microscopy techniques. While the Fourier-transform infrared spectroscopy was used to characterize the functional groups on the surface of carbon spheres. High sensitivity was exhibited when this material was used in electrochemical detection (square wave anodic stripping voltammetry) of heavy metal ions due to the porous structure. And the potential application for simultaneous detection of heavy metal ions was also investigated.

  13. Highly ordered three-dimensional macroporous carbon spheres for determination of heavy metal ions

    International Nuclear Information System (INIS)

    Zhang, Yuxiao; Zhang, Jianming; Liu, Yang; Huang, Hui; Kang, Zhenhui

    2012-01-01

    Highlights: ► Highly ordered three dimensional macroporous carbon spheres (MPCSs) were prepared. ► MPCS was covalently modified by cysteine (MPCS–CO–Cys). ► MPCS–CO–Cys was first time used in electrochemical detection of heavy metal ions. ► Heavy metal ions such as Pb 2+ and Cd 2+ can be simultaneously determined. -- Abstract: An effective voltammetric method for detection of trace heavy metal ions using chemically modified highly ordered three dimensional macroporous carbon spheres electrode surfaces is described. The highly ordered three dimensional macroporous carbon spheres were prepared by carbonization of glucose in silica crystal bead template, followed by removal of the template. The highly ordered three dimensional macroporous carbon spheres were covalently modified by cysteine, an amino acid with high affinities towards some heavy metals. The materials were characterized by physical adsorption of nitrogen, scanning electron microscopy, and transmission electron microscopy techniques. While the Fourier-transform infrared spectroscopy was used to characterize the functional groups on the surface of carbon spheres. High sensitivity was exhibited when this material was used in electrochemical detection (square wave anodic stripping voltammetry) of heavy metal ions due to the porous structure. And the potential application for simultaneous detection of heavy metal ions was also investigated.

  14. 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

  15. Polyacrylonitrile-Derived Sponge-Like Micro/Macroporous Carbon for Selective CO2 Separation.

    Science.gov (United States)

    Guo, Li-Ping; Hu, Qing-Tao; Zhang, Peng; Li, Wen-Cui; Lu, An-Hui

    2018-03-25

    CO 2 capture under a dynamical flow situation requires adsorbents possessing balanced proportion of macropores as diffusion path and micropores as adsorption reservoir. However, the construction of interconnected micro-/macropores structure coupled with abundant nitrogen species into one carbon skeleton remains a challenge. Here, we report a new approach to prepare sponge-like carbon with a well-developed micro-/macroporous structure and enriched nitrogen species through aqueous phase polymerization of acrylonitrile in the presence of graphene oxide. The tension stress caused by the uniform thermal shrinkage of polyacrylonitrile during the pyrolysis together with the favorable flexibility of graphene oxide sheets are responsible for the formation of the sponge-like morphology. The synergistic effect of micro-/macroporous framework and rich CO 2 -philic site enables such carbon to decrease resistance to mass transfer and show high CO 2 dynamic selectivity over N 2 (454) and CH 4 (11), as well as good CO 2 capacity at 298 K under low CO 2 partial pressure (0.17 bar, a typical CO 2 partial pressure in flue gas). The above attributes make this porous carbon a promising candidate for CO 2 capture from flue gas, methane sources and other relevant applications. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. 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.

  17. A practical technique for the fabrication of highly ordered macroporous structures of inorganic oxides

    International Nuclear Information System (INIS)

    Tang Fengqiu; Uchikoshi, Tetsuo; Sakka, Yoshio

    2006-01-01

    Well-defined macroporous ceramics consisting of SiO 2 , TiO 2 and ZrO 2 have been fabricated via a template-assisted colloidal processing technique. Close-packed polymer spheres were first prepared as a template using centrifugation or gravitational sedimentation, followed by infiltration with alkoxide precursors. The centrifugation should be preferred because it is a less time-consuming process and the materials are better ordered. The removal of the template beads was achieved by calcination of the organic-inorganic hybrids at appropriate temperatures, yielding well-ordered macroporous ceramics. The arrangement of the porous structures could be changing the preparation of the packed polymer templates. Some novel arrangements of macropores were obtained in these macroporous ceramics: a simple square-packed arrangement for SiO 2 , the coexistence of hexagonal close-packed and simple close-packed arrangements for TiO 2 , and face-centered cubic packed arrangement for ZrO 2 . The resulting highly structured ceramics could have applications in areas ranging from quantum electronics to photocatalysis and battery materials

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

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Sharon Chien-Yu, E-mail: sharonlin114@gmail.com [The University of Queensland, Pharmacy Australia Centre of Excellence, 20 Cornwall Street, Woolloongabba, Brisbane QLD 4102 (Australia); Wang, Yiwei, E-mail: yiweiwang@anzac.edu.au [The University of Queensland, Pharmacy Australia Centre of Excellence, 20 Cornwall Street, Woolloongabba, Brisbane QLD 4102 (Australia); Wertheim, David F., E-mail: d.wertheim@kingston.ac.uk [Faculty of Science, Engineering and Computing, Kingston University, Kingston upon Thames, Surrey KT1 2EE (United Kingdom); Coombes, Allan G.A., E-mail: allancoombes@pharmacy.psu.ac.th [Faculty of Pharmaceutical Sciences, Prince of Songkla University, Hat Yai, Songkhla 90112 (Thailand)

    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 1 h 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 (48–69 μm), 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 150 μm 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. - Highlights: • Nerve cells were encapsulated in macroporous alginate fibres for use in nerve repair. • Fibres were produced from alginate solution containing gelatin porogens and cells.

  19. Spatial distribution of heterocyclic organic matter compounds at macropore surfaces in Bt-horizons

    Science.gov (United States)

    Leue, Martin; Eckhardt, Kai-Uwe; Gerke, Horst H.; Ellerbrock, Ruth H.; Leinweber, Peter

    2017-04-01

    The illuvial Bt-horizon of Luvisols is characterized by coatings of clay and organic matter (OM) at the surfaces of cracks, biopores and inter-aggregate spaces. The OM composition of the coatings that originate from preferential transport of suspended matter in macropores determines the physico-chemical properties of the macropore surfaces. The analysis of the spatial distribution of specific OM components such as heterocyclic N-compounds (NCOMP) and benzonitrile and naphthalene (BN+NA) could enlighten the effect of macropore coatings on the transport of colloids and reactive solutes during preferential flow and on OM turnover processes in subsoils. The objective was to characterize the mm-to-cm scale spatial distribution of NCOMP and BN+NA at intact macropore surfaces from the Bt-horizons of two Luvisols developed on loess and glacial till. In material manually separated from macropore surfaces the proportions of NCOMP and BN+NA were determined by pyrolysis-field ionization mass spectrometry (Py-FIMS). These OM compounds, likely originating from combustion residues, were found increased in crack coatings and pinhole fillings but decreased in biopore walls (worm burrows and root channels). The Py-FIMS data were correlated with signals from C=O and C=C groups and with signals from O-H groups of clay minerals as determined by Fourier transform infrared spectroscopy in diffuse reflectance mode (DRIFT). Intensive signals of C15 to C17 alkanes from long-chain alkenes as main components of diesel and diesel exhaust particulates substantiated the assumption that burning residues were prominent in the subsoil OM. The spatial distribution of NCOMP and BN+NA along the macropores was predicted by partial least squares regression (PLSR) using DRIFT mapping spectra from intact surfaces and was found closely related to the distribution of crack coatings and pinholes. The results emphasize the importance of clay coatings in the subsoil to OM sorption and stabilization

  20. 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.

  1. Structure, MC3T3-E1 cell response, and osseointegration of macroporous titanium implants covered by a bioactive microarc oxidation coating with microporous structure.

    Science.gov (United States)

    Zhou, Rui; Wei, Daqing; Cheng, Su; Feng, Wei; Du, Qing; Yang, Haoyue; Li, Baoqiang; Wang, Yaming; Jia, Dechang; Zhou, Yu

    2014-04-09

    Macroporous Ti with macropores of 50-400 μm size is prepared by sintering Ti microbeads with different diameters of 100, 200, 400, and 600 μm. Bioactive microarc oxidation (MAO) coatings with micropores of 2-5 μm size are prepared on the macroporous Ti. The MAO coatings are composed of a few TiO2 nanocrystals and lots of amorphous phases with Si, Ca, Ti, Na, and O elements. Compared to compact Ti, the MC3T3-E1 cell attachment is prolonged on macroporous Ti without and with MAO coatings; however, the cell proliferation number increases. These results are contributed to the effects of the space structure of macroporous Ti and the surface chemical feature and element dissolution of the MAO coatings during the cell culture. Macroporous Ti both without and with MAO coatings does not cause any adverse effects in vivo. The new bone grows well into the macropores and micropores of macroporous Ti with MAO coatings, showing good mechanical properties in vivo compared to Ti, MAO-treated Ti, and macroporous Ti because of its excellent osseointegration. Moreover, the MAO coatings not only show a high interface bonding strength with new bones but also connect well with macroporous Ti. Furthermore, the pushing out force for macroporous Ti with MAO coatings increases significantly with increasing microbead diameter.

  2. Entrapment of dispersed pancreatic islet cells in CultiSpher-S macroporous gelatin microcarriers: Preparation, in vitro characterization, and microencapsulation.

    Science.gov (United States)

    Del Guerra, S; Bracci, C; Nilsson, K; Belcourt, A; Kessler, L; Lupi, R; Marselli, L; De Vos, P; Marchetti, P

    2001-12-20

    Immunoprotection of pancreatic islets for successful allo- or xenotransplantation without chronic immunosuppression is an attractive, but still elusive, approach for curing type 1 diabetes. It was recently shown that, even in the absence of fibrotic overgrowth, other factors, mainly insufficient nutrition to the core of the islets, represent a major barrier for long-term survival of intraperitoneal microencapsulated islet grafts. The use of dispersed cells might contribute to solve this problem due to the conceivably easier nutritional support to the cells. In the present study, purified bovine islets, prepared by collagenase digestion and density gradient purification, and dispersed bovine islet cells, obtained by trypsin and DNAsi (viability > 90%), were entrapped into either 2% (w/v) sodium alginate (commonly used for encapsulation purposes) or (dispersed islet cells only) macroporous gelatin microcarriers (CulthiSpher-S, commonly used for the production of biologicals by animal cells). Insulin release studies in response to glucose were performed within 1 week and after 1 month from preparation of the varying systems and showed no capability of dispersed bovine islet cells within sodium alginate microcapsules to sense glucose concentration changes. On the contrary, bovine islet cells entrapped in CulthiSpher-S microcarriers showed maintained capacity of increasing insulin secretion upon enhanced glucose concentration challenge. In this case, insulin release was approximately 60% of that from intact bovine islets within sodium alginate microcapsules. MTT and hematoxylineosin staining of islet cell-containing microcarriers showed the presence of viable and metabolically active cells throughout the study period. This encouraging functional data prompted us to test whether the microcarriers could be immunoisolated for potential use in transplantation. The microcarriers were embedded within 3% sodium alginate, which was then covered with a poly-L-lysine layer and a

  3. Monodispersed macroporous architecture of nickel-oxide film as an anode material for thin-film lithium-ion batteries

    International Nuclear Information System (INIS)

    Wu, Mao-Sung; Lin, Ya-Ping

    2011-01-01

    A nickel-oxide film with monodispersed open macropores was prepared on a stainless-steel substrate by electrophoretic deposition of a polystyrene-sphere monolayer followed by anodic electrodeposition of nickel oxy-hydroxide. The deposited films convert to cubic nickel oxide after annealing at 400 o C for 1 h. Galvanostatic charge and discharge results indicate that the nickel-oxide film with monodispersed open macropores is capable of delivering a higher capacity than the bare nickel-oxide film, especially in high-rate charge and discharge processes. The lithiation capacity of macroporous nickel oxide reaches 1620 mA h g -1 at 1 C current discharge and decreases to 990 mA h g -1 at 15 C current discharge. The presence of monodispersed open macropores in the nickel-oxide film might facilitate the electrolyte penetration, diffusion, and migration. Electrochemical reactions between nickel oxide and lithium ions are therefore markedly improved by this tailored film architecture.

  4. 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.

  5. Separation of scutellarin from crude extracts of Erigeron breviscapus (vant.) Hand. Mazz. by macroporous resins.

    Science.gov (United States)

    Gao, Min; Huang, Wei; Liu, Chun-Zhao

    2007-10-15

    Scutellarin, a flavone glycoside, popularly used in the treatment of heart disease, has been efficiently separated using macroporous resins from crude extracts of Chinese medicinal plant Erigeron breviscapus (vant.) Hand. Mazz. HPD-800 resin offered the best adsorption and desorption capacity for scutellarin among the eight macroporous resins tested, and its adsorption data at 25 degrees C fit best to the Langmuir isotherm. The dynamic adsorption and desorption experiments have been carried out on a HPD-800 resin packed column to optimize the separation process of scutellarin from the crude extracts of E. breviscapus. After one run treatment with HPD-800 resin, the scutellarin content in the product was increased 15.69-fold from 2.61% to 40.96% with a recovery yield of 95.01%. The preparative separation process via adsorption-desorption method developed in this study provides a new approach for scale-up separation and purification of scutellarin for its wide pharmaceutical use.

  6. Evaluation of new macroporous resins for the removal of uranium and plutonium from waste streams

    International Nuclear Information System (INIS)

    Koenst, J.W.; Herald, W.R.

    1976-01-01

    Organic ion exchange resins were evaluated for 238 Pu(IV), 238 Pu(VI), and 233 U(VI) removal from water. The capacity of the resins and equilibrium coefficients (Kd) were compared with each other and to bone char--an inorganic adsorbent consisting of hydroxyapatite (HAP) for which data is available. Bone char gave the best results for the removal of 238 Pu(IV), Amberlite XE279 (one of the new macroporous resins) gave the best results for 238 Pu(VI), and another macroporous resin, Dowex-MSA-1, gave good results for 233 U(VI). Kd values were shown to be a function of pH

  7. 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.

  8. Thermal-Conductivity Studies of Macro-porous Polymer-Derived SiOC Ceramics

    Science.gov (United States)

    Qiu, L.; Li, Y. M.; Zheng, X. H.; Zhu, J.; Tang, D. W.; Wu, J. Q.; Xu, C. H.

    2014-01-01

    A three-dimensional reticular macro-porous SiOC ceramics structure, made of spherical agglomerates, has been thermally characterized using a freestanding sensor-based method. The effective thermal conductivity of the macro-porous SiOC ceramics, including the effects of voids, is found to be to at room temperature, comparable with that of alumina aerogel or carbon aerogel. These results suggest that SiOC ceramics hold great promise as a thermal insulation material for use at high temperatures. The measured results further reveal that the effective thermal conductivity is limited by the low solid-phase volume fraction for the SiOC series processed at the same conditions. For SiOC ceramics processed under different pyrolysis temperatures, the contact condition between neighboring particles in the SiOC networks is another key factor influencing the effective thermal conductivity.

  9. 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.

  10. 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

    disturbance and compaction of the soil surface. Hypothetically introducing fully surface-connected macropores into the calibrated model resulted in a 22% increase in the loss of solute to the drain, indicating the significance of the hydraulic conditions at the soil surface and the model specification thereof......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...... concentration. The exchange was overpredicted and too rapid when the soil aggregate size (distance between macropores) obtained from an image analysis of soil cores was used in the model. On this basis, the model assumption of instant equilibration of the solute across the matrix porosity, disregarding small...

  11. 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.

  12. Preparation of thin layer materials with macroporous microstructure for SOFC applications

    International Nuclear Information System (INIS)

    Marrero-Lopez, D.; Ruiz-Morales, J.C.; Pena-Martinez, J.; Canales-Vazquez, J.; Nunez, P.

    2008-01-01

    A facile and versatile method using polymethyl methacrylate (PMMA) microspheres as pore formers has been developed to prepare thin layer oxide materials with controlled macroporous microstructure. Several mixed oxides with fluorite and perovskite-type structures, i.e. doped zirconia, ceria, ferrites, manganites, and NiO-YSZ composites have been prepared and characterised by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), nitrogen adsorption and mercury porosimetry. The synthesised materials are nanocrystalline and present a homogeneous pore distribution and relatively high specific surface area, which makes them interesting for SOFC and catalysis applications in the intermediate temperature range. - Graphical abstract: Thin films materials of mixed oxides with potential application in SOFC devices have been prepared with macroporous microstructure using PMMA microspheres as pore formers. Display Omitted

  13. Non-lithographic method of forming ordered arrays of silicon pillars and macropores

    International Nuclear Information System (INIS)

    Mills, David; Kolasinski, Kurt W

    2005-01-01

    Micrometre-scale Si pillars are formed by chemically enhanced laser ablation using nanosecond excimer laser irradiation of a Si single crystal in the presence of SF 6 . We demonstrate the importance of precursor holes in determining the positioning of the pillars and show that we can control the initiation of precursor holes by ruling a grating into the Si substrate prior to irradiation. A rule defines an edge from which the laser light diffracts. Near-field amplification of the laser intensity enhances the formation of the precursor holes and aligns them parallel to the rule. The pillars can be thinned and eventually removed by wet chemical etching in aqueous KOH, resulting first in ordered arrays of extremely high aspect ratio pillars (e.g. tens of micrometres in length, with ∼ 10 nm tips) and then macropores. The shape of the macropore is determined by crystallography and the anisotropy of the wet etchant

  14. 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 sauce, and indicated that peptide may be the contributor to the umami taste in Chinese soy sauce. Copyright © 2015 Elsevier Ltd. All rights reserved.

  15. Poly(glycidyl methacrylate-co-ethylene glycol dimethacrylate)/clay composites

    International Nuclear Information System (INIS)

    Marinovic, S.; Vukovic, Z.; Nastasovic, A.; Milutinovic-Nikolic, A.; Jovanovic, D.

    2011-01-01

    Highlights: → We synthesized macroporous composites of poly(GMA-co-EGDMA) and either raw or acid modified clay. → Morphological, textural and thermal properties of the composite with acid modified clay were significantly changed with retained macroporosity. → Composite with raw clay has enhanced thermal stability. - Abstract: In this study, macroporous composites of poly(glycidyl methacrylate-co-ethylene glycol dimethacrylate) i.e. poly(GMA-co-EGDMA) and clay were prepared by radical suspension copolymerization. The composites with either raw (S 0 ) or acid-modified clay (S A ) were characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and thermogravimetric (TG) and textural analysis. The morphological, textural and thermal properties of the composite with raw clay (CP-S 0 ) differed slightly from those of the copolymer (CP), with exception of the thermal stability expressed in the shifting of the initial degradation temperature from 125 deg. C for CP to 210 deg. C for CP-S 0 . On the other hand, composite with modified clay (CP-S A ) was a material with significantly changed morphology, porous structure parameters and a qualitatively different thermal behavior in comparison to CP and CP-S 0 . CP-S A had mass residue, after heating at 600 deg. C, three times higher than the amount of S A introduced into the reaction system. This indicates a different manner of incorporation of S A , compared to S 0 , into the composite. Both the obtained composites retained their macroporosity and might be used in all applications that involve macroporous copolymers and, due to the altered thermal properties, their application may be extended.

  16. Three-dimensional macroporous nanoelectronic networks as minimally invasive brain probes

    Science.gov (United States)

    Xie, Chong; Liu, Jia; Fu, Tian-Ming; Dai, Xiaochuan; Zhou, Wei; Lieber, Charles M.

    2015-12-01

    Direct electrical recording and stimulation of neural activity using micro-fabricated silicon and metal micro-wire probes have contributed extensively to basic neuroscience and therapeutic applications; however, the dimensional and mechanical mismatch of these probes with the brain tissue limits their stability in chronic implants and decreases the neuron-device contact. Here, we demonstrate the realization of a three-dimensional macroporous nanoelectronic brain probe that combines ultra-flexibility and subcellular feature sizes to overcome these limitations. Built-in strains controlling the local geometry of the macroporous devices are designed to optimize the neuron/probe interface and to promote integration with the brain tissue while introducing minimal mechanical perturbation. The ultra-flexible probes were implanted frozen into rodent brains and used to record multiplexed local field potentials and single-unit action potentials from the somatosensory cortex. Significantly, histology analysis revealed filling-in of neural tissue through the macroporous network and attractive neuron-probe interactions, consistent with long-term biocompatibility of the device.

  17. Hydrophobic, Hydrophilic, and Amphiphilic Polyglycocarbonates with Linear and Macrocyclic Architectures from Bicyclic Glycocarbonates Derived from CO2 and Glucoside

    KAUST Repository

    Pati, Debasis

    2017-02-09

    Two bicyclic glycocarbonates were synthesized in five steps from α-methyl-d-glucoside without resorting to phosgene or to its derivatives for the first time. The 4- and 6-positions of glucose were modified to introduce a six-membered carbonate ring, using CO as the carbonylating reagent; the 2- and 3-positions of the same glucoside substrate were first transformed into either methyl or triethylene glycol monomethyl ether groups to protect these positions from undesirable reactions and also to impart hydrophobicity in the first case and hydrophilicity in the second. The polymerization behavior of these bicyclic glycocarbonates was then investigated under different conditions. On the one hand, through ring-opening polymerization of the above monomers, linear polyglycocarbonate homopolymers and diblock copolymers were obtained initiated by p-methylbenzyl alcohol using 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD) as catalyst; on the other hand, macrocyclic polyglycocarbonate homopolymers and diblock copolymers were grown using 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) which served as zwitterionic initiator. The various architectures derived were all thoroughly characterized by NMR, GPC, and MALDI-tof and shown to exhibit the expected structure. Finally, the self-assembly of linear and macrocyclic amphiphilic copolyglycocarbonates in water was investigated and characterized by cryo-TEM.

  18. The impact of different phytosterols on the molecular dynamics in the hydrophobic/hydrophilic interface phosphatidylcholine- liposomes

    DEFF Research Database (Denmark)

    Hellgren, Lars; Sandelius, A.S.

    2001-01-01

    Plant sterols differ from cholesterol in having an alkyl group at Delta -24, and, in the case of stigmasterol, also a Delta -22 double bond. The effects of 10 mol% of three plant sterols (campesterol, fl-sitosterol, stigmasterol) and cholesterol on the molecular dynamics and phase behavior...... in multilamellar liposomes made from different phosphatidylcholine (PC) molecular species have been compared, utilizing the fluorescent probe Laurdan (2-dimethyl-amino-6-laurylnaphthalene). Laurdan reports the molecular mobility in the hydrophilic/hydrophobic interface of the membrane by determining the rate...... of dipolar relaxation of water molecules close to the glycerol backbone of PC. Our results showed that the Delta -24 alkyl group of plant sterols did not affect their ability to reduce molecular mobility in this region of the PC membranes. However, the plant sterols had a decreased capacity compared...

  19. Hydrophobic, Hydrophilic, and Amphiphilic Polyglycocarbonates with Linear and Macrocyclic Architectures from Bicyclic Glycocarbonates Derived from CO2 and Glucoside

    KAUST Repository

    Pati, Debasis; Feng, Xiaoshuang; Hadjichristidis, Nikolaos; Gnanou, Yves

    2017-01-01

    Two bicyclic glycocarbonates were synthesized in five steps from α-methyl-d-glucoside without resorting to phosgene or to its derivatives for the first time. The 4- and 6-positions of glucose were modified to introduce a six-membered carbonate ring, using CO as the carbonylating reagent; the 2- and 3-positions of the same glucoside substrate were first transformed into either methyl or triethylene glycol monomethyl ether groups to protect these positions from undesirable reactions and also to impart hydrophobicity in the first case and hydrophilicity in the second. The polymerization behavior of these bicyclic glycocarbonates was then investigated under different conditions. On the one hand, through ring-opening polymerization of the above monomers, linear polyglycocarbonate homopolymers and diblock copolymers were obtained initiated by p-methylbenzyl alcohol using 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD) as catalyst; on the other hand, macrocyclic polyglycocarbonate homopolymers and diblock copolymers were grown using 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) which served as zwitterionic initiator. The various architectures derived were all thoroughly characterized by NMR, GPC, and MALDI-tof and shown to exhibit the expected structure. Finally, the self-assembly of linear and macrocyclic amphiphilic copolyglycocarbonates in water was investigated and characterized by cryo-TEM.

  20. In vitro behavior of human mesenchymal stem cells on poly(N-isopropylacrylamide) based biointerfaces obtained by matrix assisted pulsed laser evaporation

    Science.gov (United States)

    Icriverzi, Madalina; Rusen, Laurentiu; Sima, Livia Elena; Moldovan, Antoniu; Brajnicov, Simona; Bonciu, Anca; Mihailescu, Natalia; Dinescu, Maria; Cimpean, Anisoara; Roseanu, Anca; Dinca, Valentina

    2018-05-01

    The use of smart coatings with tunable characteristics in bioengineering fields is directly correlated with the surface chemical and topographical properties, the method of preparation, and also with the type of cells implied for the specific application. In this work, a versatile surface modification technique based on the use of lasers (Matrix-Assisted Pulsed Laser Evaporation (MAPLE)) was used to yield poly(N-isopropylacrylamide) (pNIPAM) and its derivatives (amine, azide and amide terminated pNIPAM) functional and termoresponsive thin films. Surface properties of pNIPAM and its derivative films such as morphology, roughness and hydrophobic/hydrophilic character, as well as the thermoresponsive capacity were investigated by atomic force microscopy and contact angle measurements. The chemical characteristics of the pNIPAM based thin films were analysed by Fourier Transform Infrared Spectroscopy (FTIR). The chemical functionality was kept for all the samples obtained by MAPLE and the thermoresponse was demonstrated by the change in the contact angle and thickness values when the temperature was shifted from 37 °C to 24 °C for all the materials tested, with a smaller change for maleimide terminated pNIPAM. Biological assays performed in vitro (fluorescence microscopy and Scanning Electron Microscopy (SEM)) confirmed the conditioning of the early mesenchymal stem cell (MSC) growth by specific chemistry of the coatings. The cell imaging analysis revealed no cytotoxic effect of pNIPAM surfaces irrespective of type of functionalization. An increased proliferation rate of the cells grown on pNIPAM-azide surfaces and a lower cell density on pNIPAM-maleimide surfaces compared to the pNIPAM surfaces was observed, which can direct their use to potential surfaces in regenerative medicine approaches.

  1. Additively Manufactured Macroporous Titanium with Silver-Releasing Micro-/Nanoporous Surface for Multipurpose Infection Control and Bone Repair - A Proof of Concept.

    Science.gov (United States)

    Jia, Zhaojun; Xiu, Peng; Xiong, Pan; Zhou, Wenhao; Cheng, Yan; Wei, Shicheng; Zheng, Yufeng; Xi, Tingfei; Cai, Hong; Liu, Zhongjun; Wang, Caimei; Zhang, Weiping; Li, Zhijiang

    2016-10-26

    Restoring large-scale bone defects, where osteogenesis is slow while infections lurk, with biomaterials represents a formidable challenge in orthopedic clinics. Here, we propose a scaffold-based multipurpose anti-infection and bone repairing strategy to meet such restorative needs. To do this, personalized multifunctional titanium meshes were produced through an advanced additive manufacturing process and dual "TiO 2 -poly(dopamine)/Ag (nano)" post modifications, yielding macroporous constructs with micro-/nanoporous walls and nanosilver bullets immobilized/embedded therein. Ultrahigh loading capacity and durable release of Ag + were accomplished. The scaffolds were active against planktonic/adherent bacteria (Gram-negative and positive) for up to 12 weeks. Additionally, they not only defended themselves from biofilm colonization but also helped destroy existing biofilms, especially in combination with antibiotics. Further, the osteoblasts/bacteria coculture study displayed that the engineered surfaces aided MG-63 cells to combat bacterial invasion. Meanwhile, the scaffolds elicited generally acceptable biocompatibility (cell adhesion, proliferation, and viability) and hastened osteoblast differentiation and maturation (alkaline phosphatase production, matrix secretion, and calcification), by synergy of micro-/nanoscale topological cues and bioactive catecholamine chemistry. Although done ex vivo, these studies reveal that our three-in-one strategy (infection prophylaxis, infection fighting, and bone repair) has great potential to simultaneously prevent/combat infections and bridge defected bone. This work provides new thoughts to the use of enabling technologies to design biomaterials that resolve unmet clinical needs.

  2. Preparation of Silica Monoliths with Macropores and Mesopores and of High Specific Surface Area with Low Shrinkage using a Template Induced Method

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Jianyu [Shanghai Normal Univ., Shanghai (China); Lu, Yan [Shanghai Institute of Technology, Shanghai (China); Whiting, Roger [AUT Univ., Auckland (New Zealand)

    2013-02-15

    In this study we report a new method for the synthesis of a silica monolithic column bed with bimodal pores (throughpores and mesopores). The template induced synthesis method was used to direct bimodal pores simultaneously instead of the usual post base-treating method. Block polymer Pluronic F127 was chosen as a dual-function template to form hierarchically porous silica monolith with both macropores and mesopores. This is a simplification of the method of monolithic column preparation. Poly(ethylene glycol) was used as a partial substitute for F127 can effectively prevent shrinkage during the monolith aging process without losing much surface area (944 m{sup 2}/g to 807 m{sup 2}/g). More importantly, the resultant material showed a much narrower mesopore size (centered at 6 nm) distribution than that made using only F127 as the template reagent, which helps the mass transfer process. The solvent washing method was used to remove the remaining organic template, and it was proved to be effective enough. The new synthesis method makes the fabrication of the silica monolithic column (especially capillary column) much easier. All the structure parameters indicate that monolith PFA05 prepared by the above method is a good material for separation, with the merits of much higher surface area than usual commercial HPLC silica particles, suitable mesopore volume, narrow mesopore size distribution, low shrinkage and it is easily prepared.

  3. 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

  4. 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.

  5. 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.

  6. PEG-modified macroporous poly(glycidyl methacrylate) and poly(2-hydroxyethyl methacrylate) microspheres to reduce non-specific protein adsorption

    Czech Academy of Sciences Publication Activity Database

    Hlídková, Helena; Horák, Daniel; Proks, Vladimír; Kučerová, Z.; Pekárek, Michal; Kučka, Jan

    2013-01-01

    Roč. 13, č. 4 (2013), s. 503-511 ISSN 1616-5187 R&D Projects: GA ČR GCP207/12/J013; GA ČR GAP206/12/0381; GA MŠk 7E12053 EU Projects: European Commission(XE) 246513 - NADINE Institutional support: RVO:61389013 Keywords : coatings * glycidyl methacrylate * 2-hydroxyethyl methacrylate Subject RIV: CD - Macromolecular Chemistry Impact factor: 3.650, year: 2013

  7. 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.

  8. Honeycomb-like graphitic ordered macroporous carbon prepared by pyrolysis of ammonium bicarbonate

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Liancheng [Key Laboratory of Colloid and Interface Chemistry, Shandong University, Jinan, Shandong 250100 (China); Zhang, Junhao, E-mail: jhzhang6@mail.ustc.edu.cn [Key Laboratory of Colloid and Interface Chemistry, Shandong University, Jinan, Shandong 250100 (China); School of Biology and Chemical Engineering, Jiangsu University of Science and Technology, Zhenjiang, Jiangsu 212003 (China); Xu, Liqiang; Qian, Yitai [Key Laboratory of Colloid and Interface Chemistry, Shandong University, Jinan, Shandong 250100 (China)

    2011-10-15

    Graphical abstract: Honeycomb-like graphitic macroporous carbon (HGMC) with big pores centered at 1-3 {mu}m, has been prepared by controlling the reaction temperature and amount of NH{sub 4}HCO{sub 3} at 550 {sup o}C in a sealed reaction system. Possible formation processes of HGMC are discussed on the experimental results. It is believed that the in situ formed MgO microparticles play a template role during the preparation of HGMC. Highlights: {yields} Honeycomb-like graphitic carbon was synthesized at 550 {sup o}C. {yields} The honeycomb-like graphitic carbon is macroposous structures. {yields} The formed MgO microparticles play a template role during the HGMC formation. {yields} The method can be expended to synthesize other porous or hollow carbon material. -- Abstract: Honeycomb-like graphitic macroporous carbon (HGMC) was synthesized by means of pyrolysis of NH{sub 4}HCO{sub 3} using Mg powder as reductant in an autoclave at 550 {sup o}C. The characterization of structure and morphology was carried out by X-ray diffraction (XRD), Raman spectrum, field-emission scanning electron microscopy (FESEM), and (High-resolution) transmission electron microscope [(HR)TEM]. The results of nitrogen adsorption-desorption indicate that the products are macropore materials with the pore size of 1-3 {mu}m, and the Brunauer-Emett-Teller (BET) surface area was 14 m{sup 2}/g. As a typical morphology, the possible growth process of HGMC was also investigated and discussed. The experimental results show that the in situ formed MgO microparticles play a template role during the HGMC formation.

  9. Homogenization-assisted cavitation hybrid rotation extraction and macroporous resin enrichment of dihydroquercetin from Larix gmelinii.

    Science.gov (United States)

    Xia, Yu; Wang, Yinhang; Li, Wei; Ma, Chunhui; Liu, Shouxin

    2017-12-01

    Cavitation hybrid rotation, which was and is still looked upon as an unavoidable nuisance in the flow systems, for extraction processing intensification of active chemical compounds from natural products. In this study, a homogenization-assisted cavitation hybrid rotation extraction method was applied to extract dihydroquercetin (DHQ) from larch (Larix gmelinii) wood root. The extraction parameters were optimized in single factor experiments with the DHQ extraction yields as the response values. The optimum conditions were as follows: number of extractions, three; ethanol volume fraction for the extraction, 60%; liquid-solid ratio for homogenization, 10mL/g; homogenization time, 8min; liquid-solid ratio for cavitation extraction, 9mL/g, and cavitation extraction time, 35min. Under these conditions, the DHQ content in extract was 4.50±0.02mg/g, and the extraction efficiency was higher than those of traditional techniques. Cavitation can be effectively used to improve the extraction rate by increasing the mass transfer rates and possible rupture of cell wall due to formation of microcavities leading to higher product yields with reduced processing time and solvent consumption. After the extraction process, macroporous resin column chromatography was used to concentrate and purify the DHQ. Three resins were selected from fifteen macroporous resins for further investigation of their performance. Among these resins, AB-8 resin exhibited relatively better adsorption capacities and desorption ratios for DHQ. The ethanol volume fraction of the solutions for sample loading and desorption, and flow rates for loading and desorption were optimized for the macroporous resin column chromatography. Copyright © 2017 Elsevier B.V. All rights reserved.

  10. Highly ordered macroporous woody biochar with ultra-high carbon content as supercapacitor electrodes

    International Nuclear Information System (INIS)

    Jiang, Junhua; Zhang, Lei; Wang, Xinying; Holm, Nancy; Rajagopalan, Kishore; Chen, Fanglin; Ma, Shuguo

    2013-01-01

    Woody biochar monolith with ultra-high carbon content and highly ordered macropores has been prepared via one-pot pyrolysis and carbonization of red cedar wood at 750 °C without the need of post-treatment. Energy-dispersive spectroscope (EDX) and scanning electron microscope (SEM) studies show that the original biochar has a carbon content of 98 wt% with oxygen as the only detectable impurity and highly ordered macroporous texture characterized by alternating regular macroporous regions and narrow porous regions. Moreover, the hierarchically porous biochar monolith has a high BET specific surface area of approximately 400 m 2 g −1 . We have studied the monolith material as supercapacitor electrodes under acidic environment using electrochemical and surface characterization techniques. Electrochemical measurements show that the original biochar electrodes have a potential window of about 1.3 V and exhibit typical rectangular-shape voltammetric responses and fast charging–discharging behavior with a gravimetric capacitance of about 14 F g −1 . Simple activation of biochar in diluted nitric acid at room temperature leads to 7 times increase in the capacitance (115 F g −1 ). Because the HNO 3 -activation slightly decreases rather than increases the BET surface area of the biochar, an increase in the coverage of surface oxygen groups is the most likely origin of the substantial capacitance improvement. This is supported by EDX, X-ray photoelectron spectroscopy (XPS), and Raman measurements. Preliminary life-time studies show that biochar supercapacitors using the original and HNO 3 -activated electrodes are stable over 5000 cycles without performance decays. These facts indicate that the use of woody biochar is promising for its low cost and it can be a good performance electrode with low environmental impacts for supercapacitor applications

  11. Electrochemical study of nitrobenzene reduction using novel Pt nanoparticles/macroporous carbon hybrid nanocomposites

    International Nuclear Information System (INIS)

    Zhang Yufan; Zeng Lijun; Bo Xiangjie; Wang Huan; Guo Liping

    2012-01-01

    Graphical abstract: A one-step microwave-assisted route for rapidly synthesizing Pt nanoparticles ensemble on macroporous carbon hybrid nanocomposites (PNMPC) has been reported. As a novel electrode material, the excellent electrochemical behavior of nitrobenzene was investigated thoroughly at the PNMPC modified glassy carbon electrode. And moreover, the modified electrode was successfully applied to the determination of nitrobenzene in real samples. Highlights: ► One-step microwave-assisted heating synthesis Pt nanoparticles/macroporous carbon hybrid nanocomposites (PNMPC). ► Catalytic rate constant being 3.14 × 10 4 M −1 s −1 for NB in pH 7.0. ► Sensitive electrochemical detection of NB at the PNMPC/Nafion/GC electrode. ► The electrode showing excellent anti-interference ability and good stability for NB. - Abstract: Novel Pt nanoparticles (PN) ensemble on macroporous carbon (MPC) hybrid nanocomposites (PNMPC) were prepared through a rapidly and simple one-step microwave-assisted heating procedure. The obtained PNMPC was characterized by transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TGA) and electrochemical methods. The electrochemical reduction of nitrobenzene (NB) was thoroughly investigated at the PNMPC modified glassy carbon (GC) electrode, and the catalytic rate constant was calculated to be 3.14 × 10 4 M −1 s −1 for NB. A sensitive NB sensor was developed based on the PNMPC/GC electrode, which showed a wide linear range (1–200 μM), low detection limit (50 nM), high sensitivity (6.93 μA μM −1 ), excellent anti-interference ability and good stability. And moreover, the electrode was successfully applied to the determination of NB in real samples.

  12. Honeycomb-like graphitic ordered macroporous carbon prepared by pyrolysis of ammonium bicarbonate

    International Nuclear Information System (INIS)

    Wang, Liancheng; Zhang, Junhao; Xu, Liqiang; Qian, Yitai

    2011-01-01

    Graphical abstract: Honeycomb-like graphitic macroporous carbon (HGMC) with big pores centered at 1-3 μm, has been prepared by controlling the reaction temperature and amount of NH 4 HCO 3 at 550 o C in a sealed reaction system. Possible formation processes of HGMC are discussed on the experimental results. It is believed that the in situ formed MgO microparticles play a template role during the preparation of HGMC. Highlights: → Honeycomb-like graphitic carbon was synthesized at 550 o C. → The honeycomb-like graphitic carbon is macroposous structures. → The formed MgO microparticles play a template role during the HGMC formation. → The method can be expended to synthesize other porous or hollow carbon material. -- Abstract: Honeycomb-like graphitic macroporous carbon (HGMC) was synthesized by means of pyrolysis of NH 4 HCO 3 using Mg powder as reductant in an autoclave at 550 o C. The characterization of structure and morphology was carried out by X-ray diffraction (XRD), Raman spectrum, field-emission scanning electron microscopy (FESEM), and (High-resolution) transmission electron microscope [(HR)TEM]. The results of nitrogen adsorption-desorption indicate that the products are macropore materials with the pore size of 1-3 μm, and the Brunauer-Emett-Teller (BET) surface area was 14 m 2 /g. As a typical morphology, the possible growth process of HGMC was also investigated and discussed. The experimental results show that the in situ formed MgO microparticles play a template role during the HGMC formation.

  13. 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

    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...... modeling were used to construct a new map dividing Denmark into risk categories for macropore flow. This map can be combined with other tools to identify areas where there is a high risk of contaminants leaching out of the root zone....

  14. Site selective generation of sol-gel deposits in layered bimetallic macroporous electrode architectures.

    Science.gov (United States)

    Lalo, Hélène; Bon-Saint-Côme, Yémima; Plano, Bernard; Etienne, Mathieu; Walcarius, Alain; Kuhn, Alexander

    2012-02-07

    The elaboration of an original composite bimetallic macroporous electrode containing a site-selective sol-gel deposit is reported. Regular colloidal crystals, obtained by a modified Langmuir-Blodgett approach, are used as templates for the electrogeneration of the desired metals in the form of a well-defined layered bimetallic porous electrode. This porous matrix shows a spatially modulated electroactivity which is subsequently used as a strategy for targeted electrogeneration of a sol-gel deposit, exclusively in one predefined part of the porous electrode.

  15. 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......-porosity, suggesting that density is the main control of functional soil structure and gas and solute transport at the Silstrup site. Linking gas transport and chemical tracer experiments with X-ray CT based visualization and quantification of macro-porosity was found to be a powerful method to understand field scale...

  16. Aqueous cholesteric liquid crystals using uncharged rodlike polypeptides. Polypeptide vesicles by conformation-specific assembly. Ordered chiral macroporous hybrid silica-polypeptide composites

    Science.gov (United States)

    Bellomo, Enrico Giuseppe

    2005-07-01

    Aqueous cholesteric liquid crystals using uncharged rodlike polypeptides . The aqueous, lyotropic liquid-crystalline phase behavior of an alpha helical polypeptide, has been studied using optical microscopy and X-ray scattering. Solutions of optically pure polypeptide were found to form cholesteric liquid crystals at volume fractions that decreased with increasing average chain length. At very high volume fractions, the formation of a hexagonal mesophase was observed. The pitch of the cholesteric phase could be varied by a mixture of enantiomeric samples, where the pitch increased as the mixture approached equimolar. The cholesteric phases could be untwisted, using either magnetic field or shear flow, into nematic phases, which relaxed into cholesterics upon removal of field or shear. We have found that the phase diagram of this polypeptide in aqueous solution parallels that of poly(gamma-benzyl glutamate) in organic solvents, thus providing a useful system for liquid-crystal applications requiring water as solvent. Polypeptide vesicles by conformation-specific assembly. We have found that block copolymers composed of polypeptide segments provide significant advantages in controlling both the function and supramolecular structure of bioinspired self-assemblies. Incorporation of the stable chain conformations found in proteins into block copolymers was found to provide an additional element of control, beyond amphiphilicity and composition that defines self-assembled architecture. The abundance of functionality present in amino acids, and the ease by which they can be incorporated into these materials, also provides a powerful mechanism to impart block copolypeptides with function. This combination of structure and function work synergistically to enable significant advantages in the preparation of therapeutic agents as well as provide insight into design of self-assemblies beginning to approach the complexity of natural structures such as virus capsids. Ordered

  17. Amphiphilic polymer promoted assembly of macroporous graphene/SnO2 frameworks with tunable porosity for high-performance lithium storage.

    Science.gov (United States)

    Huang, Yanshan; Wu, Dongqing; Wang, Jinzuan; Han, Sheng; Lv, Lu; Zhang, Fan; Feng, Xinliang

    2014-06-12

    3D macroporous graphene/SnO2 frameworks (MGTFs) are fabricated by amphiphilic polymer-promoted assembly method, which exhibit controllable macroporous structure and outstanding lithium storage performance. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Investigation the effect of porosity on corrosion of macroporous silicon in 1.0 M sodium hydroxide solution using weight loss measurements, electrochemical methods and scanning electron microscope

    International Nuclear Information System (INIS)

    Lai, Chuan; Xiang, Zhen

    2015-01-01

    Highlights: • The dissolution of silicon wafers conforms Faraday’s laws of electrolysis. • The porosity effect on macroporous silicon corrosion was investigated. • The corrosion rate increase linearly with porosity increasing. • The porosity effect on activation parameters was obtained. - Abstract: In this study, the macroporous silicon has been fabricated by electrochemical anodization. The dissolution of n-type silicon wafers in etching solution conforms Faraday’s laws of electrolysis. The fabricated macroporous silicon with different porosity corrosion in 1.0 M NaOH was systemically investigated by weight loss measurements, electrochemical methods and scanning electron microscope. Results show that with the porosity increasing, the corrosion rate of macroporous silicon in 1.0 M NaOH increases linearly. In addition, the increase of corrosion rate of macroporous silicon with relative higher porosity was determined by the pre-exponential factor.

  19. Transport of radionuclides by concentrated brine in a porous medium with micropore-macropore structure

    International Nuclear Information System (INIS)

    Hassanizadeh, S.M.

    1987-01-01

    This work concerns itself with the study of effects of soil aggregation and high salt concentrations on the transport of radionuclides by concentrated brine flowing through an aggregated porous medium. The medium is considered to be composed of porous rock aggregates separated by macropores through which the brine flows and transport of salt and radionuclides takes place. The aggregates contain dead-end pores, cracks, and stationary pockets collectively called micropores. The micropore space does not contribute to the flow, but it serves as a storage for salt and radionuclides. Adsorption of radionuclides takes place at internal surfaces of aggregates where they assume that a linear equilibrium isotherm describes the process. A one-dimensional numerical model is developed which is based on two sets of equations: one set for the flow and transport of salt and another set for transport of radionuclides. Results of numerical experiments clearly indicate that the existence of high salt concentrations markedly reduces the peak of nuclides concentration and slows down their movement. Also, it is found that diffusive mass exchange between macropores and aggregates results in a pronounced lowering of the radionuclides concentration peaks. 9 references, 7 figures

  20. 3D macroporous graphene frameworks for supercapacitors with high energy and power densities.

    Science.gov (United States)

    Choi, Bong Gill; Yang, Minho; Hong, Won Hi; Choi, Jang Wook; Huh, Yun Suk

    2012-05-22

    In order to develop energy storage devices with high power and energy densities, electrodes should hold well-defined pathways for efficient ionic and electronic transport. Herein, we demonstrate high-performance supercapacitors by building a three-dimensional (3D) macroporous structure that consists of chemically modified graphene (CMG). These 3D macroporous electrodes, namely, embossed-CMG (e-CMG) films, were fabricated by using polystyrene colloidal particles as a sacrificial template. Furthermore, for further capacitance boost, a thin layer of MnO(2) was additionally deposited onto e-CMG. The porous graphene structure with a large surface area facilitates fast ionic transport within the electrode while preserving decent electronic conductivity and thus endows MnO(2)/e-CMG composite electrodes with excellent electrochemical properties such as a specific capacitance of 389 F/g at 1 A/g and 97.7% capacitance retention upon a current increase to 35 A/g. Moreover, when the MnO(2)/e-CMG composite electrode was asymmetrically assembled with an e-CMG electrode, the assembled full cell shows remarkable cell performance: energy density of 44 Wh/kg, power density of 25 kW/kg, and excellent cycle life.

  1. 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.

  2. Nanocrystals-based Macroporous Materials Synthesized by Freeze-drying Combustion

    International Nuclear Information System (INIS)

    Yan, Ruiqiang; Chen, Yu; Lin, Ye; Chen, Fanglin

    2016-01-01

    We present a novel freeze-drying combustion method for synthesis of macroporous powders with nano-network, using Sm 0.2 Ce 0.8 O 1.9 (SDC) as an example. The metal nitrate salt solution mixed with glycine is frozen to form homogeneous nitrate/glycine mixture and then freeze-dried through sublimation of ice crystals. Upon combustion of the freeze-dried mixture, SDC powders with macroporous microstructure consisting of 10–20 nm nanocrystals, high surface area and excellent sinterability are achieved. High resolution transmission electron microscopy (HRTEM) analysis indicates that nanodomains due to aggregation/segregation of dopants in the SDC powders obtained from freeze-drying combustion are much smaller than those in the SDC powders synthesized by the conventional nitrate solution combustion approach, demonstrating better elemental homogeneity and improved conductivity. Using low cost precursors and simple processing conditions, freeze-drying combustion can be a versatile method to synthesize nanocrystalline powders with excellent composition homogeneity for broad applications.

  3. 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.

  4. The Influence of Syndepositional Macropores on the Hydraulic Integrity of Thick Alluvial Clay Aquitards

    Science.gov (United States)

    Timms, Wendy A.; Acworth, R. Ian; Crane, Richard A.; Arns, Christoph H.; Arns, Ji-Youn; McGeeney, Dayna E.; Rau, Gabriel C.; Cuthbert, Mark O.

    2018-04-01

    Clay-rich deposits are commonly assumed to be aquitards which act as natural hydraulic barriers due to their low hydraulic connectivity. Postdepositional weathering processes are known to increase the permeability of aquitards in the near surface but not impact on deeper parts of relatively thick formations. However, syndepositional processes affecting the hydraulic properties of aquitards have previously received little attention in the literature. Here, we analyze a 31 m deep sediment core recovered from an inland clay-rich sedimentary sequence using a combination of techniques including particle size distribution and microscopy, centrifuge dye tracer testing and micro X-ray CT imaging. Subaerial deposition of soils within these fine grained alluvial deposits has led to the preservation of considerable macropores (root channels or animal burrows). Connected pores and macropores thus account for vertical hydraulic conductivity (K) of 4.2×10-9 m/s (geometric mean of 13 samples) throughout the thick aquitard, compared to a matrix K that is likely sediment was deposited must be considered when aquitards are investigated as potential natural hydraulic barriers and illustrate the value of combining multiple investigation techniques for characterizing clay-rich deposits.

  5. 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. Copyright © 2016 Elsevier Ltd. All rights reserved.

  6. Poly(furfuryl alcohol)

    Indian Academy of Sciences (India)

    This paper describes a facile hydrothermal approach to the large-scale synthesis of well-dispersed poly(furfuryl alcohol) (PFA) nanospheres with an average diameter of 350 nm in the presence of poly(vinyl pyrrolidone) (PVP). Scanning electron microscopy and transmission electron microscopy studies showed that ...

  7. Process-based modelling of a headwater catchment in semi-arid conditions: the influence of macropore flow

    NARCIS (Netherlands)

    Schaik, N.L.M.B.; Bronstert, A.; Jong, S.M.; Jetten, V.G.; Dam, van J.C.; Ritsema, C.J.; Schnabel, S.

    2014-01-01

    Subsurface stormflow is thought to occur mainly in humid environments with steep terrains. However, in semi-arid areas, preferential flow through macropores can also result in a significant contribution of subsurface stormflow to catchment runoff for varying catchment conditions. Most hydrological

  8. Modification of macroporous membranes by graft co-polymerization induced by pre-irradiation with an electron accelerator

    International Nuclear Information System (INIS)

    Grasselli, M.; Yoshii, Fumio

    1999-01-01

    Glycidyl methacrylate (GMA) and N,N-dimethylacrylamide (DMAA) have been co-grafted on hollow fiber membranes of macroporous polyethylene. Grafted copolymers have been obtained with different ratios of the monomers (molar ratio between 0 and 2 DMAA/GMA). The properties of the modified membranes are studied

  9. Nickel oxide film with open macropores fabricated by surfactant-assisted anodic deposition for high capacitance supercapacitors.

    Science.gov (United States)

    Wu, Mao-Sung; Wang, Min-Jyle

    2010-10-07

    Nickel oxide film with open macropores prepared by anodic deposition in the presence of surfactant shows a very high capacitance of 1110 F g(-1) at a scan rate of 10 mV s(-1), and the capacitance value reduces to 950 F g(-1) at a high scan rate of 200 mV s(-1).

  10. SOLVENT EFFECTS IN THE LIQUID-PHASE HYDRATION OF CYCLOHEXENE CATALYZED BY A MACROPOROUS STRONG ACID ION-EXCHANGE RESIN

    NARCIS (Netherlands)

    PANNEMAN, HJ; BEENACKERS, AACM

    1992-01-01

    The liquid-phase hydration of cyclohexene, a pseudo first order reversible reaction catalyzed by a strong acid ion exchange resin, macroporous Amberlite XE 307, was investigated in solvent mixtures of water and sulfolane. A decrease by a factor of 3 and 6 is observed in the experimentally measured

  11. [Investigation on the process of sapindus saponin purified with macroporous adsorption resin and screening of its bacteriostasis].

    Science.gov (United States)

    Fu, Yong; Lei, Peng; Han, Yu-mei; Yan, Dan

    2010-02-01

    To study the technological parameters of the purification process of saponins with macroporous adsorption resin. The adsorptive characteristics and elutive parameters of the process were studied by taking the elutive and purified ratio of saponins as markers. Bacteriostasis activity of each parts eluted was evaluated by the mean of cup-plate method. 13.6 mL of the extraction of sapindus saponin (crude drugs 0.01 g/mL) was purified with a column of macroporous adsorption resin (phi15 mm x H90 mm, dry weight 2.5 g) and washed with 3BV of distilled water, then eluted with 3BV of 30% ethanol and 3BV of 70% ethanol, most of saponins were collected in the 70% ethanol. With macroporous adsorption resin adsorbing and purifying, the elutive ratio of saponins was 93.8% and the purity reached 250.1%. So this process of applying macroporous adsorption resin to adsorb and purify saponins is feasible, and supplies reference to the purification of other types of saponin.

  12. Magnetic poly(glycidyl methacrylate) microspheres for protein capture.

    Science.gov (United States)

    Koubková, Jana; Müller, Petr; Hlídková, Helena; Plichta, Zdeněk; Proks, Vladimír; Vojtěšek, Bořivoj; Horák, Daniel

    2014-09-25

    The efficient isolation and concentration of protein antigens from complex biological samples is a critical step in several analytical methods, such as mass spectrometry, flow cytometry and immunochemistry. These techniques take advantage of magnetic microspheres as immunosorbents. The focus of this study was on the development of new superparamagnetic polymer microspheres for the specific isolation of the tumor suppressor protein p53. Monodisperse macroporous poly(glycidyl methacrylate) (PGMA) microspheres measuring approximately 5 μm and containing carboxyl groups were prepared by multistep swelling polymerization of glycidyl methacrylate (GMA), 2-[(methoxycarbonyl)methoxy]ethyl methacrylate (MCMEMA) and ethylene dimethylacrylate (EDMA) as a crosslinker in the presence of cyclohexyl acetate as a porogen. To render the microspheres magnetic, iron oxide was precipitated within their pores; the Fe content in the particles received ∼18 wt%. Nonspecific interactions between the magnetic particles and biological media were minimized by coating the microspheres with poly(ethylene glycol) (PEG) terminated by carboxyl groups. The carboxyl groups of the magnetic PGMA microspheres were conjugated with primary amino groups of mouse monoclonal DO-1 antibody using conventional carbodiimide chemistry. The efficiency of protein p53 capture and the degree of nonspecific adsorption on neat and PEG-coated magnetic microspheres were determined by western blot analysis. Copyright © 2014 Elsevier B.V. All rights reserved.

  13. 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. © 2014 Institute of Food Technologists®

  14. A novel electrochemical sensor based on zirconia/ordered macroporous polyaniline for ultrasensitive detection of pesticides.

    Science.gov (United States)

    Wang, Yonglan; Jin, Jun; Yuan, Caixia; Zhang, Fan; Ma, Linlin; Qin, Dongdong; Shan, Duoliang; Lu, Xiaoquan

    2015-01-21

    A simple and mild strategy was proposed to develop a novel electrochemical sensor based on zirconia/ordered macroporous polyaniline (ZrO2/OMP) and further used for the detection of methyl parathion (MP), one of the organophosphate pesticides (OPPs). Due to the strong affinity of phosphate groups with ZrO2 and the advantages of OMP such as high catalytic activity and good conductivity, the developed sensor showed a limit of detection as low as 2.28 × 10(-10) mol L(-1) (S/N = 3) by square-wave voltammograms, and good selectivity, acceptable reproducibility and stability. Most importantly, this novel sensor was successfully applied to detect MP in real samples of apple and cabbage. It is expected that this method has potential applications in electrochemical sensing platforms with simple, sensitive, selective and fast analysis.

  15. 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.

  16. 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.

  17. 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.

  18. Hierarchically Macroporous Graphitic Nanowebs Exhibiting Ultra-fast and Stable Charge Storage Performance

    Science.gov (United States)

    Yun, Young Soo

    2018-02-01

    The macro/microstructures of carbon-based electrode materials for supercapacitor applications play a key role in their electrochemical performance. In this study, hierarchically macroporous graphitic nanowebs (HM-GNWs) were prepared from bacterial cellulose by high-temperature heating at 2400 °C. The HM-GNWs were composed of well-developed graphitic nanobuilding blocks with a high aspect ratio, which was entangled as a nanoweb structure. The morphological and microstructural characteristics of the HM-GNWs resulted in remarkable charge storage performance. In particular, the HM-GNWs exhibited very fast charge storage behaviors at scan rates ranging from 5 to 100 V s-1, in which area capacitances ranging from 8.9 to 3.8 mF cm-2 were achieved. In addition, 97% capacitance retention was observed after long-term cycling for more than 1,000,000 cycles.

  19. 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.

  20. Exchange of Th, U and Pu on macroporous ion exchange resins

    International Nuclear Information System (INIS)

    Nadkarni, M.N.; Mayankutty, P.C.; Pillai, N.S.; Shinde, S.S.

    1977-01-01

    Absorption of Th, U and Pu on macroporous ion exchangers, Amberlyst 15 (cationic) and Amberlyst A-26 (anionic) were studied in nitric acid solutions and the results were found comparable with those on their microreticular counter parts, Dowex 50x8 and Dowex IX4. With a view to evalute the efficiency of Amberlyst A-26 for the final purification of plutonium from the purex process stream, detailed studies conducted to determine the breakthrough capacity of Pu(IV) from 7.2 M nitric acid, elution by 0.5 M nitric acid and the decontamination factors for uranium and zirconium-95. Because of its faster kinetics, Amberlyst A-26 exhibited a much more efficient elution of Pu(IV) by 0.5 M nitric acid than Dowex IX4. (author)

  1. Novel method of separating macroporous arrays from p-type silicon substrate

    International Nuclear Information System (INIS)

    Peng Bobo; Wang Fei; Liu Tao; Yang Zhenya; Wang Lianwei; Fu, Ricky K. Y.; Chu, Paul K.

    2012-01-01

    This paper presents a novel method to fabricate separated macroporous silicon using a single step of photo-assisted electrochemical etching. The method is applied to fabricate silicon microchannel plates in 100 mm p-type silicon wafers, which can be used as electron multipliers and three-dimensional Li-ion microbatteries. Increasing the backside illumination intensity and decreasing the bias simultaneously can generate additional holes during the electrochemical etching which will create lateral etching at the pore tips. In this way the silicon microchannel can be separated from the substrate when the desired depth is reached, then it can be cut into the desired shape by using a laser cutting machine. Also, the mechanism of lateral etching is proposed. (semiconductor materials)

  2. Delta-sleep inducing peptide entrapment in the charged macroporous matrices

    International Nuclear Information System (INIS)

    Sukhanova, Tatiana V.; Artyukhov, Alexander A.; Gurevich, Yakov M.; Semenikhina, Marina A.; Prudchenko, Igor A.; Shtilman, Mikhail I.; Markvicheva, Elena A.

    2014-01-01

    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

  3. Purification of bioactive phenolics from Phanerochaete chysosporium biomass extract on selected macroporous resins

    Science.gov (United States)

    Idris, Z. M.; Dzahir, M. I. H. M.; Jamal, P.; Barkat, A. A.; Xian, R. L. W.

    2017-06-01

    In this study, two different types of macroporous resins known as XAD-7HP and HP-20 were evaluated for the adsorption and desorption properties against bioactive phenolics extracted from Phanerochaete chrysosporium. From the previous static sorption studies, it was found that the adsorption capacity for both resins had has no significant difference. Then, the kinetic adsorption data were analyzed with both pseudo-first-order and pseudo-second-order equations and the later performed better. The adsorption isotherm data were fitted well by both Langmuir and Freundlich models. Meanwhile in desorption study, HP-20 and XAD-7HP gave 90.52% and 88.28% recoveries, respectively. Considering the desorption results of the macroporous resins, HP-20 and XAD-7HP were packed in chromatography column to further purify the phenolics. For dynamic adsorption, breakthrough capacity of HP-20 (0.522) was found to be higher than XAD-7HP (0.131). Different ethanol concentrations (30% to 50% (v/v)) were investigated at fixed flowrate (1 ml/min) on phenolics recovery from both types of resins. The highest recovery of bioactive phenolics was 94.3% using XAD-7HP resins at 50% (v/v) of ethanol. Only 77.1% of bioactive phenolics were recovered using HP-20 resin at the same experimental conditions. The purified extract subsequently was analyzed using HPLC. The results showed that three phenolics (gallic acid 3,4-dihydroxybenzoic acid and 4-hydroxybenzoic acid) were identified with higher concentrations as compared to non-purified extract. Finally, the purified extract was tested for scavenging activity against DPPH, and it showed that the activity increased significantly to 90.80% from 59.94% in non-purified extract.

  4. 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.

  5. 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.

  6. Soil macropores: Control on infiltration, hillslope and surface hydrology on a reclaimed surface-mined watershed

    International Nuclear Information System (INIS)

    Guebert, M.D.; Gardner, T.W.

    1992-01-01

    The hydrologic response of a surface-mined watershed in central Pennsylvania is controlled by rapid macropore flow within the unsaturated man-made topsoil. Newly reclaimed surface-mined watersheds in central Pennsylvania exhibit low steady-state infiltration rates (1--2 cm/hr) and produce runoff dominated by infiltration-excess overland flow. However, within four years after reclamation, infiltration rates on some mine surfaces approach premined rates (8 cm/hr). As infiltration rate increases, the volume of infiltrated water increases, but the total porosity of minesoil matrix remains constant. There is little change in the surface discharge volume, indicating that infiltrated water continues to contribute to the basin surface discharge by the processes of throughflow and return flow. Throughflow in the topsoil horizon occurs in rapid response to rainfall input, producing large volumes of water with throughflow rates closely related to rainfall rates and with throughflow peaks following rainfall peaks by only minutes. Increased return flow alters the shape of the surface runoff hydrograph by slightly lagging behind infiltration excess overland flow. These changes in the shape of the surface runoff hydrograph reduce the potential for severe gully erosion on the reclaimed site. In addition, throughflow water remains predominantly in the topsoil horizon, and therefore has limited contact with potentially acid-producing backfill. Better understanding of macropore flow processes in reclaimed minesoils will help investigators evaluate past strategies and develop new reclamation techniques that will minimize the short-term surface erosional effects of mining and reclamation, while optimizing the long-term effluent and groundwater quality

  7. 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. Copyright © 2014 Elsevier B.V. All rights reserved.

  8. 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.

  9. Qualitative Analysis of Polyphenols in Macroporous Resin Pretreated Pomegranate Husk Extract by HPLC-QTOF-MS.

    Science.gov (United States)

    Abdulla, Rahima; Mansur, Sanawar; Lai, Haizhong; Ubul, Ablikim; Sun, Guangying; Huang, Guozheng; Aisa, Haji Akber

    2017-09-01

    Pomegranate (Punica granatum L.) husk is a traditional herbal medicine abundant in phenolic compounds and plays some roles in the treatment of oxidative stress, bacterial and viral infection, diabetes mellitus, and acute and chronic inflammation. Identification and determination of polyphenols in macroporous resin pretreated pomegranate husk extract by high performance liquid chromatography coupled with quadrupole time-of-flight tandem mass spectrometry (HPLC-QTOF-MS). The total polyphenols of pomegranate husk were prepared by ethanol extraction followed by pretreatment with HPD-300 macroporous resin. The polyphenolic compounds were qualitatively analysed by HPLC-QTOF-MS in negative electrospray ionisation (ESI) mode at different collision energy (CE) values. A total of 50 polyphenols were detected in the extract of pomegranate husk, including 35 hydrolysable tannins and 15 flavonoids with distinct retention time, fragmentation behaviours and characteristics, and the accurate mass-to-charge ratios at low, moderate and high CE values. Of these, we identified nine compounds for the first time in the pomegranate husk, including hexahydroxydiphenoyl-valoneoyl-glucoside (HHDP-valoneyl-glucoside), galloyl-O-punicalin, rutin, hyperoside, quercimeritrin, kaempferol-7-O-rhahmano-glucoside, luteolin-3'-O-arabinoside, luteolin-3'-O-glucoside, and luteolin-4'-O-glucoside. To validate the specificity and accuracy of mass spectrometry in the detection of polyphenols, as compared to the fragmentation pathways of granatin B in detail, including the HHDP-valoneyl- glucoside was first identified from pomegranate husk. The study provides evidence for the quality control and development of novel drugs based on polyphenols from the pomegranate husk. Copyright © 2017 John Wiley & Sons, Ltd. Copyright © 2017 John Wiley & Sons, Ltd.

  10. Bioinspired Poly(2-oxazolines

    Directory of Open Access Journals (Sweden)

    Helmut Schlaad

    2011-02-01

    Full Text Available Poly(2-oxazolines are regarded as pseudopeptides, thus bioinspired polymers, due to their structural relationship to polypeptides. Materials and solution properties can be tuned by varying the side-chain (hydrophilic-hydrophobic, chiral, bioorganic, etc., opening the way to advanced stimulus-responsive materials and complex colloidal structures. The bioinspired “smart” solution and aggregation behavior of poly(2-oxazolines in aqueous environments are discussed in this review.

  11. Raman study of magnesium induced conversion of polyU·polyA duplexes to polyU·polyA·polyU triplexes

    OpenAIRE

    Herrera, S. J. Espinoza; Štepánek, J.

    2010-01-01

    Raman titration experiment with magnesium salt added gradually to aqueous solution of duplexes formed by RNA homopolynucleotides polyU and polyA was performed to reveal its effect on homopolynucleotide complexes. Statistical analysis of obtained spectral set has confirmed the effect already found by less structurally sensitive methods [Nucleic Acids Res. 31(17) (2003), 5101–5107] that at sufficiently high concentrations magnesium causes transformation of polyU·polyA duplexes to polyU·polyA·po...

  12. Large-scale synthesis of macroporous SnO2 with/without carbon and their application as anode materials for lithium-ion batteries

    International Nuclear Information System (INIS)

    Wang Fei; Yao Gang; Xu Minwei; Zhao Mingshu; Sun Zhanbo; Song Xiaoping

    2011-01-01

    Highlights: → A new hard template prepared from glucose was used to synthesize macroporous SnO 2 . → SnO 2 and SnO 2 /C were prepared in a simple and large-scale synthetic method. → Combining the nanostructure design and active/inactive nanocomposite concept. → The obtained SnO 2 /C composite exhibited superior cycling performance. - Abstract: The macroporous SnO 2 is prepared using close packed carbonaceous sphere template which synthesized from glucose by hydrothermal method. The structure and morphology of the macroporous SnO 2 are evaluated by XRD and FE-SEM. The average pore size of the macroporous SnO 2 is about 190 nm and its wall thickness is less than 10 nm. When the macroporous SnO 2 filled with carbon is used as an anode material for lithium-ion battery, the capacity is about 380 mAh g -1 after 70 cycles. The improved cyclability is attributed to the carbon matrix which is used as an effective physical buffer to prevent the collapse of the well dispersed macroporous SnO 2 .

  13. Large-scale synthesis of macroporous SnO{sub 2} with/without carbon and their application as anode materials for lithium-ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    Wang Fei; Yao Gang; Xu Minwei [MOE Key Laboratory for Non-equilibrium Synthesis and Modulation of Condensed Matter, School of Science, Xi' an Jiaotong University, Shaan Xi 710049 (China); Zhao Mingshu, E-mail: zhaomshu@mail.xjtu.edu.cn [MOE Key Laboratory for Non-equilibrium Synthesis and Modulation of Condensed Matter, School of Science, Xi' an Jiaotong University, Shaan Xi 710049 (China); Sun Zhanbo [MOE Key Laboratory for Non-equilibrium Synthesis and Modulation of Condensed Matter, School of Science, Xi' an Jiaotong University, Shaan Xi 710049 (China); Song Xiaoping, E-mail: xpsong@mail.xjtu.edu.cn [MOE Key Laboratory for Non-equilibrium Synthesis and Modulation of Condensed Matter, School of Science, Xi' an Jiaotong University, Shaan Xi 710049 (China)

    2011-05-19

    Highlights: > A new hard template prepared from glucose was used to synthesize macroporous SnO{sub 2}. > SnO{sub 2} and SnO{sub 2}/C were prepared in a simple and large-scale synthetic method. > Combining the nanostructure design and active/inactive nanocomposite concept. > The obtained SnO{sub 2}/C composite exhibited superior cycling performance. - Abstract: The macroporous SnO{sub 2} is prepared using close packed carbonaceous sphere template which synthesized from glucose by hydrothermal method. The structure and morphology of the macroporous SnO{sub 2} are evaluated by XRD and FE-SEM. The average pore size of the macroporous SnO{sub 2} is about 190 nm and its wall thickness is less than 10 nm. When the macroporous SnO{sub 2} filled with carbon is used as an anode material for lithium-ion battery, the capacity is about 380 mAh g{sup -1} after 70 cycles. The improved cyclability is attributed to the carbon matrix which is used as an effective physical buffer to prevent the collapse of the well dispersed macroporous SnO{sub 2}.

  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

    with no biodegradation of the MCPA at all nodes; 2) preferential flow (including a wormhole) of water with no biodegradation of the MCPA at all nodes; 3) simple matrix flow of water with average biodegradation of the MCPA at all nodes, which corresponds to results derived from a conventional homogenized soil sample; 4...... 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......, however, the risk of MCPA-leaching below one meter depth increase drastically with low degradation potential along the wall of macropores/wormholes....

  15. Macroporous Inverse Opal-like MoxC with Incorporated Mo Vacancies for Significantly Enhanced Hydrogen Evolution.

    Science.gov (United States)

    Li, Feng; Zhao, Xianglong; Mahmood, Javeed; Okyay, Mahmut Sait; Jung, Sun-Min; Ahmad, Ishfaq; Kim, Seok-Jin; Han, Gao-Feng; Park, Noejung; Baek, Jong-Beom

    2017-07-25

    The hydrogen evolution reaction (HER) is one of the most important pathways for producing pure and clean hydrogen. Although platinum (Pt) is the most efficient HER electrocatalyst, its practical application is significantly hindered by high-cost and scarcity. In this work, an Mo x C with incorporated Mo vacancies and macroporous inverse opal-like (IOL) structure (Mo x C-IOL) was synthesized and studied as a low-cost efficient HER electrocatalyst. The macroporous IOL structure was controllably fabricated using a facile-hard template strategy. As a result of the combined benefits of the Mo vacancies and structural advantages, including appropriate hydrogen binding energy, large exposed surface, robust IOL structure and fast mass/charge transport, the synthesized Mo x C-IOL exhibited significantly enhanced HER electrocatalytic performance with good stability, with performance comparable or superior to Pt wire in both acidic and alkaline solutions.

  16. Industrial-scale preparation of akebia saponin D by a two-step macroporous resin column separation.

    Science.gov (United States)

    Wu, Yue; Ji, De; Liu, Yunfei; Zhang, Chunfeng; Yang, Zhonglin

    2012-06-26

    A simple and efficient procedure for the industrial preparation of akebia saponin D, one of the bioactive compounds commonly found in the well-known Chinese Medicinal herb Dipsaci Radix, was developed. First, HPD-722 was selected from among 10 kinds of macroporous absorption resins. Following this step, the purity of akebia saponin D was increased about 10 times from 6.27% to 59.41%. In order to achieve a higher purity, ADS-7 was chosen from among five kinds of macroporous absorption resins, and the purity of akebia saponin D was increased from 59.41% to 95.05%. The result indicated HPD-722 and ADS-7 were the most suitable resins to purify akebia saponin D from Dipsaci Radix. Under these conditions, large-scale preparation of akebia saponin D was carried out successfully. The preparation method is simple, efficient, and has been demonstrated to be effective for large scale preparations of akebia saponin D from Dipsaci Radix.

  17. Prediction of biopore- and matrix-dominated flow from X-ray CT-derived macropore network characteristics

    DEFF Research Database (Denmark)

    Naveed, Muhammad; Møldrup, Per; Schaap, Marcel G

    2016-01-01

    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......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......) were extracted from the topsoil (5 cm to 8.5 cm depth) in a 15m15m 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...

  18. The evaluation/application of Hydrus-2D model for simulating macro-pores flow in loess soil

    OpenAIRE

    Xuexuan Xu; Shahmir Ali Kalhoro; Wen yuan Chen; Sajjad Raza

    2017-01-01

    Soil hydraulic properties were mainly governed by soil structures especially when the structures is full of the connected soil macro-pores. Therefore, the good hydrological models need to be well documented for revealing the process of soil water movement affected by soil medium. The Hydrus-2D model with double domain was recommended in simulating water movement in a heterogeneous medium of soil. To evaluate the performance of the double domain Hydrus-2D model in loess soil, the dynamic of so...

  19. Human embryonic stem cell-encapsulation in alginate microbeads in macroporous calcium phosphate cement for bone tissue engineering

    Science.gov (United States)

    Tang, Minghui; Chen, Wenchuan; Weir, Michael D.; Thein-Han, Wahwah; Xu, Hockin H. K.

    2012-01-01

    Human embryonic stem cells (hESCs) are exciting for regenerative medicine applications because of their strong proliferative ability and multilineage differentiation capability. To date there has been no report on hESC seeding with calcium phosphate cement (CPC). The objective of this study was to investigate hESC-derived mesenchymal stem cell (hESCd-MSC) encapsulation in hydrogel microbeads in macroporous CPC for bone tissue engineering. hESCs were cultured to form embryoid bodies (EBs), and the MSCs were then migrated out of the EBs. hESCd-MSCs had surface markers characteristic of MSCs, with positive alkaline phosphatase (ALP) staining when cultured in osteogenic medium. hESCd-MSCs were encapsulated in alginate at a density of 1 million cells/mL, with an average microbead size of 207 µm. CPC contained mannitol porogen to create a porosity of 64% and macropores with size of 218 µm, with 20% absorbable fibers for additional porosity when the fibers degrade. hESCd-MSCs encapsulated in microbeads in CPC had good viability from 1 to 21 d. ALP gene expression at 21 d was 25-fold that at 1 d. Osteocalcin (OC) at 21 d was two orders of magnitude of that at 1 d. ALP activity in colorimetric p-nitrophenyl phosphate assay at 21 d was 5-fold that at 1 d. Mineral synthesis by the encapsulated hESCd-MSCs at 21 d was 7-fold that at 1 d. Potential benefits of the CPC-stem cell paste include injectability, intimate adaptation to complex-shaped bone defects, ease in contouring to achieve esthetics in maxillofacial repairs, and in situ setting ability. In conclusion, hESCd-MSCs were encapsulated in alginate microbeads in macroporous CPC showing good cell viability, osteogenic differentiation and mineral synthesis for the first time. The hESCd-MSC-encapsulating macroporous CPC construct is promising for bone regeneration in a wide range of orthopedic and maxillofacial applications. PMID:22633970

  20. Umbilical cord stem cells released from alginate-fibrin microbeads inside macroporous and biofunctionalized calcium phosphate cement for bone regeneration

    Science.gov (United States)

    Chen, Wenchuan; Zhou, Hongzhi; Weir, Michael D.; Bao, Chongyun; Xu, Hockin H.K.

    2012-01-01

    The need for bone repair has increased as the population ages. The objectives of this study were to (1) develop a novel biofunctionalized and macroporous calcium phosphate cement (CPC) containing alginate-fibrin microbeads encapsulating human umbilical cord mesenchymal stem cells (hUCMSCs); and (2) investigate hUCMSC proliferation and osteogenic differentiation inside CPC for the first time. Macroporous CPC was developed using calcium phosphate powders, chitosan, and gas-foaming porogen. Five types of CPCs were fabricated: CPC control, CPC + 0.05% fibronectin (Fn), CPC + 0.1% Fn, CPC + 0.1% Arg-Gly-Asp (RGD), and CPC + 0.1% Fn + 0.1% RGD. Alginate-fibrin microbeads containing 106 hUCMSCs/mL were encapsulated in the CPC paste. After CPC had set, the degradable microbeads released hUCMSCs inside CPC. hUCMScs proliferated inside CPC, with cell density at 21 d being 4-fold that at 1 d. CPC + 0.1% RGD had the highest cell density, which was 4-fold that of CPC control. The released cells differentiated into the osteogenic lineage and synthesized bone minerals. hUCMSCs inside the CPC + 0.1% RGD construct had gene expressions of alkaline phosphatase (ALP), osteocalcin (OC) and collagen I, which were twice those of CPC control. Mineral synthesis by hUCMSCs inside the CPC + 0.1% RGD construct was 2-fold that in CPC control. RGD and Fn incorporation in CPC did not compromise the strength of CPC, which matched the reported strength of cancellous bone. In conclusion, degradable microbeads released the hUCMSCs which proliferated, differentiated and synthesized minerals inside the macroporous CPC for the first time. CPC with RGD greatly enhanced cell functions. The novel biofunctionalized and macroporous CPC-microbead-hUCMSC construct is promising for bone tissue engineering applications. PMID:22391411

  1. Study on the use of macroporous cation exchange resins for the separation and purification of uranium from thorium

    International Nuclear Information System (INIS)

    Rastogi, R.K.; Mahajan, M.A.; Chaudhuri, N.K.

    1992-01-01

    The possibility of using macroporous cation exchange resins for the purification of uranium from thorium relevant to the final purification of uranium after reprocessing thorium breeder fuel was explored. Two macroporous cation exchange resins were studied and compared with a commonly used gel type resin. Batch experiments and column experiments were performed to generate equilibrium data and to optimise the procedure for the separation of U from Th under process condition. Under the same condition Tulsion T-42 gave product U containing 0.1% of Th, while Amberlyst-15 gave the product U containing 1% of Th. Loading and washing rates were much higher (120 ml/hr) than those used for gel type resins (40 ml/hr). Though the volume of wash required for >90% recovery of U is more than that required with the gel type resin the disadvantage due to that is more than compensated by the use of high flow rate of loading and washing to give higher throughput. Thus there is a definite advantage of U purification with macroporous resins as compared to usual gel type resins. (author). 23 refs., 3 figs., 10 tabs

  2. Tracking Single DNA Nanodevices in Hierarchically Meso-Macroporous Antimony-Doped Tin Oxide Demonstrates Finite Confinement.

    Science.gov (United States)

    Mieritz, Daniel; Li, Xiang; Volosin, Alex; Liu, Minghui; Yan, Hao; Walter, Nils G; Seo, Dong-Kyun

    2017-06-27

    Housing bio-nano guest devices based on DNA nanostructures within porous, conducting, inorganic host materials promise valuable applications in solar energy conversion, chemical catalysis, and analyte sensing. Herein, we report a single-template synthetic development of hierarchically porous, transparent conductive metal oxide coatings whose pores are freely accessible by large biomacromolecules. Their hierarchal pore structure is bimodal with a larger number of closely packed open macropores (∼200 nm) at the higher rank and with the remaining space being filled with a gel network of antimony-doped tin oxide (ATO) nanoparticles that is highly porous with a broad size range of textual pores mainly from 20-100 nm at the lower rank. The employed carbon black template not only creates the large open macropores but also retains the highly structured gel network as holey pore walls. Single molecule fluorescence microscopic studies with fluorophore-labeled DNA nanotweezers reveal a detailed view of multimodal diffusion dynamics of the biomacromolecules inside the hierarchically porous structure. Two diffusion constants were parsed from trajectory analyses that were attributed to free diffusion (diffusion constant D = 2.2 μm 2 /s) and to diffusion within an average confinement length of 210 nm (D = 0.12 μm 2 /s), consistent with the average macropore size of the coating. Despite its holey nature, the ATO gel network acts as an efficient barrier to the diffusion of the DNA nanostructures, which is strongly indicative of physical interactions between the molecules and the pore nanostructure.

  3. A simple method for preparation of macroporous polydimethylsiloxane membrane for microfluidic chip-based isoelectric focusing applications

    Energy Technology Data Exchange (ETDEWEB)

    Ou Junjie [Department of Mechanical and Mechatronics Engineering, University of Waterloo, 200 University Ave West, Waterloo, Ontario, N2L 3G1 (Canada); Department of Chemistry, University of Waterloo, 200 University Ave West, Waterloo, Ontario, N2L 3G1 (Canada); Ren, Carolyn L., E-mail: c3ren@mecheng1.uwaterloo.ca [Department of Mechanical and Mechatronics Engineering, University of Waterloo, 200 University Ave West, Waterloo, Ontario, N2L 3G1 (Canada); Pawliszyn, Janusz [Department of Chemistry, University of Waterloo, 200 University Ave West, Waterloo, Ontario, N2L 3G1 (Canada)

    2010-03-10

    A new, simple method was reported to prepare PDMS membranes with micrometer size pores for microfluidic chip applications. The pores were formed by adding polystyrene and toluene into PDMS prepolymer solution prior to spin-coating and curing. The resulting PDMS membrane has a thickness of around 10 {mu}m and macropores with a diameter ranging from 1 to 2 {mu}m measured using scanning electron microscope (SEM) imaging. This PDMS membrane was validated by integrating it with PDMS microfluidic chips for protein separation using isoelectric focusing mechanism coupled with whole channel imaging detection (IEF-WCID). It has been shown that five standard pI markers and a mixture of two proteins, myoglobin and {beta}-lactoglobulin, can be separated using these chips. The results indicated that this macroporous PDMS membrane can replace the dialysis membrane in PDMS chips for the IEF-WCID technique. The preparation method of macroporous PDMS membrane may be potentially applied in other fields of microfluidic chips.

  4. Effect of hierarchical meso–macroporous alumina-supported copper catalyst for methanol synthesis from CO2 hydrogenation

    International Nuclear Information System (INIS)

    Witoon, Thongthai; Bumrungsalee, Sittisut; Chareonpanich, Metta; Limtrakul, Jumras

    2015-01-01

    Highlights: • CO 2 hydrogenation over Cu-loaded unimodal and hierarchical alumina catalysts. • Cu-loaded hierarchical catalyst exhibited higher methanol selectivity and stability. • The presence of macropores reduced the probability of side reaction. - Abstract: Effects of pore structures of alumina on the catalytic performance of copper catalysts for CO 2 hydrogenation were investigated. Copper-loaded hierarchical meso–macroporous alumina (Cu/HAl) catalyst exhibited no significant difference in terms of CO 2 conversion with copper-loaded unimodal mesoporous alumina (Cu/UAl) catalyst. However, the selectivity to methanol and dimethyl ether of the Cu/HAl catalyst was much higher than that of the Cu/UAl catalyst. This was attributed to the presence of macropores which diminished the occurrence of side reaction by the shortening the mesopores diffusion path length. The Cu/HAl catalyst also exhibited much higher stability than the Cu/UAl catalyst due to the fast diffusion of water out from the catalyst pellets, alleviating the oxidation of metallic copper to CuO

  5. Bioactive glass-poly (ε-caprolactone) composite scaffolds with 3 dimensionally hierarchical pore networks

    International Nuclear Information System (INIS)

    Yun, Hui-suk; Kim, Seung-eon; Park, Eui Kyun

    2011-01-01

    Hierarchically mesoporous-macroporous-giant-porous bioactive glass/poly ε-caprolactone (PCL) composite scaffolds were prepared using a combination of the sol-gel method, evaporation-induced self-assembly process in the presence of nonionic triblock copolymer, EO 100 PO 65 EO 100 (F127), as template, salt leaching method, and rapid prototyping techniques. F127 acts as a template, inducing the formation of mesopores, NaCl with sizes between 25 and 33 μm provides macro-pores after leaching, and rapid prototyping produces giant-pores. The structure and morphology of the scaffolds were characterized by the field emission scanning electron microscopy, transmission electron microscopy, and Hg porosimetry. The mechanical properties of the scaffolds were examined by the dynamic mechanical analysis. Their in vitro bioactivities were confirmed by immersing the scaffolds in simulated body fluid. Their biocompatibilities were also evaluated by culturing human bone marrow stromal cells on the scaffolds. The scaffolds show good molding capabilities, mechanical properties, 3 dimensionally well-interconnected pore structures, bioactivities, and biocompatibilities in vitro. Depending on the amount of NaCl, the scaffolds also show unique sponge-like properties, but still retain better mechanical properties than general salt leaching derived PCL scaffolds. All of the data provide good evidence that the obtained scaffolds possess excellent potential for applications in the fields of tissue engineering and drug storage.

  6. Development of a Process for Separation of Mogroside V from Siraitia grosvenorii by Macroporous Resins

    Directory of Open Access Journals (Sweden)

    Ping Hu

    2011-08-01

    Full Text Available A separation method was developed for the preparative separation and enrichment of the non-caloric sweetener mogroside V from Siraitia grosvenorii. The adsorption properties of six macroporous resins were evaluated. Results showed that HZ 806 resin offered the best adsorption and desorption capacities. Based on the adsorption experiments on HZ 806, the adsorption data were found to fit the Freundlich model well. The pseudo-second-order kinetic model showed the highest correlation with the experimental results. Separation was performed with deionized water and 40% aqueous ethanol solution as mobile phases. In a typical run, 100 g of herb was processed and 3.38 g of mogroside V with a purity of 10.7% was harvested. This separation method provided a 15.1-fold increase in the purification factor from 0.5% to 10.7%. The present study showed that HZ 806 resins were effective for the separation and enrichment of mogroside V from S. grosvenorii.

  7. Synthesis of three-dimensionally ordered macroporous manganese dioxide-carbon nanocomposites for supercapacitors

    Science.gov (United States)

    Liu, Zhi; Tan, Xiuli; Gao, Xin; Song, Lihong

    2014-12-01

    In this article, we report a composite of MnO2 nanoparticles supported by three-dimensionally ordered macroporous carbon (MnO2/3DOM carbon nanocomposites) fabricated by means of a simple multi-component infiltration of three-dimensional templates. MnO2 nanoparticles of 2 nm-6 nm are observed to be highly dispersed on the 3DOM carbon scaffolds. Cyclic voltammetry, galvanostatic charge/discharge and electrochemical impedance spectroscopy techniques are employed to assess the properties of these nanocomposites for use in supercapacitors. The results demonstrate that MnO2 can be effectively utilized with assistance of the 3DOM carbon in the electrode. The specific capacitance of the nanocomposite electrode can reach as high as 347 F g-1 at a current density of 0.5 A g-1. Moreover, the electrode exhibit excellent charge/discharge rate and good cycling stability, retaining over 92% of its initial charge after 5500 cycles at a current density of 2.5 A g-1. Such MnO2/3DOM carbon nanocomposite represents a promising exploring direction for enhancing the device performance of metal oxide-based electrochemical supercapacitors.

  8. Understanding the peculiarities of the piezoelectric effect in macro-porous BaTiO3.

    Science.gov (United States)

    Roscow, James I; Topolov, Vitaly Yu; Bowen, Christopher R; Taylor, John; Panich, Anatoly E

    2016-01-01

    This work demonstrates the potential of porous BaTiO 3 for piezoelectric sensor and energy-harvesting applications by manufacture of materials, detailed characterisation and application of new models. Ferroelectric macro-porous BaTiO 3 ceramics for piezoelectric applications are manufactured for a range of relative densities, α  = 0.30-0.95, using the burned out polymer spheres method. The piezoelectric activity and relevant parameters for specific applications are interpreted by developing two models: a model of a 3-0 composite and a 'composite in composite' model. The appropriate ranges of relative density for the application of these models to accurately predict piezoelectric properties are examined. The two models are extended to take into account the effect of 90° domain-wall mobility within ceramic grains on the piezoelectric coefficients [Formula: see text]. It is shown that porous ferroelectrics provide a novel route to form materials with large piezoelectric anisotropy [Formula: see text] at 0.20 ≤ α ≤ 0.45 and achieve a high squared figure of merit [Formula: see text] [Formula: see text]. The modelling approach allows a detailed analysis of the relationships between the properties of the monolithic and porous materials for the design of porous structures with optimum properties.

  9. Determination of hydrogen peroxide using a Prussian Blue modified macroporous gold electrode

    International Nuclear Information System (INIS)

    Yang, Jiao; Lin, Meng; Cho, MiSuk; Lee, Youngkwan

    2015-01-01

    We describe an electrochemical sensor for hydrogen peroxide (H 2 O 2 ) that is making use of Prussian Blue (PB) electrodeposited on a macroporous (mp) gold skeleton electrode. An mp-Cu film was first prepared as a template and the converted into an mp-Au film through a replacement reaction without destructing the structure. Next, a layer of PB was electrochemically deposited on the surface of the mp-Au film. The surface morphology of the electrode was characterized by scanning electron microscopy. Attenuated total reflection infrared spectroscopy and X-ray photoelectron spectroscopy were applied to confirm the structural features. The mp-PB/Au film electrode displays high electro-catalytic activity for the reduction of H 2 O 2 at a working potential of −50 mV (vs. Ag/AgCl) and is very stable. It has a linear response to H 2 O 2 in the 50 μM to 11.3 mM concentration range and a sensitivity of 767 μA∙mM −1 cm −2 . The electrode also revealed good selectivity in the presence of electro-active species such as ascorbic acid and uric acid. (author)

  10. Photonic molecules for improving the optical response of macroporous silicon photonic crystals for gas sensing purposes.

    Science.gov (United States)

    Cardador, D; Segura, D; Rodríguez, A

    2018-02-19

    In this paper, we report the benefits of working with photonic molecules in macroporous silicon photonic crystals. In particular, we theoretically and experimentally demonstrate that the optical properties of a resonant peak produced by a single photonic atom of 2.6 µm wide can be sequentially improved if a second and a third cavity of the same length are introduced in the structure. As a consequence of that, the base of the peak is reduced from 500 nm to 100 nm, while its amplitude remains constant, increasing its Q-factor from its initial value of 25 up to 175. In addition, the bandgap is enlarged almost twice and the noise within it is mostly eliminated. In this study we also provide a way of reducing the amplitude of one or two peaks, depending whether we are in the two- or three-cavity case, by modifying the length of the involved photonic molecules so that the remainder can be used to measure gas by spectroscopic methods.

  11. Carbon nanotube-coated macroporous sponge for microbial fuel cell electrodes

    KAUST Repository

    Xie, Xing

    2012-01-01

    The materials that are used to make electrodes and their internal structures significantly affect microbial fuel cell (MFC) performance. In this study, we describe a carbon nanotube (CNT)-sponge composite prepared by coating a sponge with CNTs. Compared to the CNT-coated textile electrodes evaluated in prior studies, CNT-sponge electrodes had lower internal resistance, greater stability, more tunable and uniform macroporous structure (pores up to 1 mm in diameter), and improved mechanical properties. The CNT-sponge composite also provided a three-dimensional scaffold that was favorable for microbial colonization and catalytic decoration. Using a batch-fed H-shaped MFC outfitted with CNT-sponge electrodes, an areal power density of 1.24 W m -2 was achieved when treating domestic wastewater. The maximum volumetric power density of a continuously fed plate-shaped MFC was 182 W m -3. To our knowledge, these are the highest values obtained to date for MFCs fed domestic wastewater: 2.5 times the previously reported maximum areal power density and 12 times the previously reported maximum volumetric power density. © 2011 The Royal Society of Chemistry.

  12. Adsorbability Enhancement of Macroporous Resin by Dielectric Barrier Discharge Plasma Treatment to Phenol in Water

    Directory of Open Access Journals (Sweden)

    Shoufeng Tang

    2016-01-01

    Full Text Available In order to enhance the adsorption efficiency and economize the use of macroporous resin, we have treated it with the dielectric barrier discharge (DBD plasma to improve its adsorbing capacity for phenol. The effects of operation conditions, for instance, applied voltage, treated time, and air flow rate on resin, were investigated by adsorption kinetics and isotherms. Results showed that the adsorption data were in good agreement with the pseudo-second-order and Freundlich equation. Experimental results showed that the modified resin was 156.5 mg/g and 39.2% higher than the untreated sample, when the modified conditions were conducted for discharge voltage 20 kV, treatment time 45 min, and air flow rate 1.2 L/min. The resin was characterized by FTIR and nitrogen adsorption isotherms before and after the DBD processes. It was found that the reason for the enhancement of resin adsorbability was attributed to the DBD plasma changing the surface physical and chemical structure.

  13. In Situ Gold Nanoparticle Gradient Formation in a 3D Meso- and Macroporous Polymer Matrix.

    Science.gov (United States)

    Penders, Jelle; Rajasekharan, Anand K; Hulander, Mats; Andersson, Martin

    2017-08-01

    Herein, the development and characterization of a 3D gradient structure of gold nanoparticles is described. The gradient of gold nanoparticles is made in situ in a macroporous nonionic block copolymer hydrogel matrix, through gold ion diffusion control. The polymer provides a matrix for diffusion of gold ions, acts as a template for controlling nanoparticle growth, and facilitates the in situ reduction of gold ions to gold nanoparticles. A clear gradient in gold nanoparticles is observed across the 3D space of the polymer matrix using scanning electron microscopy, fluorescence microscopy, atomic force microscopy, and thermogravimetric analysis. The particle gradient is further functionalized with both hydrophobic and hydrophilic groups via thiol-gold linkage to demonstrate the ability to form gradients with different chemical functionalities. Using additive manufacturing, the polymer can also be printed as a porous network with possible applications for 3D cell culturing in, e.g., biomaterials research. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Glycidyl methacrylate macroporous copolymer grafted with diethylene triamine as sorbent for Reactive Black 5

    Directory of Open Access Journals (Sweden)

    Sandić Zvjezdana P.

    2014-01-01

    Full Text Available In this paper, macroporous glycidyl methacrylate and ethylene glycol dimethacrylate copolymer functionalized with diethylene triamine [PGME-deta], was evaluated as Reactive Black 5 (RB5 sorbent. Batch RB5 removal from aqueous solution by PGME-deta was investigated by varying pH, contact time, sorbent dosage, initial dye concentration and temperature. The sorption is pH sensitive having maximum at pH 2 (dye removal of 85%, decreasing with the increase of pH (dye removal of 24% at pH=11 after 60 min. Sorption kinetics was fitted to chemical-reaction and particle-diffusion models (pseudo-first-order, pseudo-second-order, intraparticle diffusion and Mckay models. The pseudo-second-order kinetic model accurately predicted the RB5 amount sorbed under all investigated operating conditions, while the intraparticle diffusion was the dominant rate-limiting mechanism. The diffusion mechanism was more prevalent with the decrease in temperature and the increase in concentration. The isotherm data was best fitted with the Langmuir model, indicating homogeneous distribution of active sites on PGME-deta and monolayer sorption, with the maximum sorption capacity of 353 mg g-1. The calculated sorption rates improved with increasing temperature and an activation energy close to 40 kJ mol-1 was determined, suggesting that chemisorption was also rate-controlling. [Projekat Ministarstva nauke Republike Srbije, br. III 43009, br. TR 37021 i br. III 45001

  15. Oriented Poly(dialkylstannane)s

    DEFF Research Database (Denmark)

    Choffat, Fabien; Fornera, Sara; Smith, Paul

    2008-01-01

    The inorganic (or 'organometallic') polymers poly(dibutylstannane), poly(dioctylstannane), and poly(didodecylstannane) have been oriented by shear forces, the tensile drawing of blends with polyethylene, and deposition from solution onto glass slides coated with all oriented, friction-deposited p......The inorganic (or 'organometallic') polymers poly(dibutylstannane), poly(dioctylstannane), and poly(didodecylstannane) have been oriented by shear forces, the tensile drawing of blends with polyethylene, and deposition from solution onto glass slides coated with all oriented, friction......-deposited poly(tetrafluoroethylene) (PTFE) layer. Orientation of the polystannanes has been examined by polarization microscopy, UV-vis spectroscopy with polarized light, and X-ray diffraction and their direction is found to depend on the length of the alkyl side groups and the method of orientation. Remarkably...

  16. Meso- and macroporous sulfonated starch solid acid catalyst for esterification of palm fatty acid

    Directory of Open Access Journals (Sweden)

    Ibrahim M. Lokman

    2016-03-01

    Full Text Available In the present work, a heterogeneous solid acid catalyst was successfully developed from starch. The catalyst was prepared by a significant two-step process; the initial step was incomplete carbonization of starch (ICS at 400 °C for 12 h and consequently followed by sulfonation process using concentrated H2SO4 to produce sulfonated-incomplete carbonized starch (ICS-SO3H. The characterization of the ICS-SO3H catalyst was done for chemical and physical properties such as X-ray diffraction (XRD, ammonia-temperature programmed desorption (NH3-TPD, surface area analysis, thermal gravimetric analysis (TGA, elemental analysis and morphology analysis by scanning electron microscope (SEM. BET results showed the structure of ICS-SO3H consists of meso- and macro-porous properties, which allowed high density of the SO3H group attached on its carbon networks. The catalytic activity of ICS-SO3H catalyst was determined by analyzing the catalyst performance to esterify palm fatty acid distillate (PFAD and sequentially produced methyl ester. The maximum free fatty acid (FFA conversion and FAME yield were as high as 94.6% and 90.4%, respectively, at 75 °C using 10:1 methanol-to-PFAD molar ratio and 2 wt.% of catalyst within 3 h. The catalyst has sufficient potential to recycle up to 6 reactions without reactivation step and any remarkable loss of catalytic activity. It revealed that the heterogeneous ICS-SO3H catalyst exhibits high stability, reusability and catalytic activity.

  17. 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

  18. Wannier–Stark electro-optical effect, quasi-guided and photonic modes in 2D macroporous silicon structures with SiO_2 coatings

    International Nuclear Information System (INIS)

    Karachevtseva, L.; Goltviansky, Yu.; Sapelnikova, O.; Lytvynenko, O.; Stronska, O.; Bo, Wang; Kartel, M.

    2016-01-01

    Highlights: • The IR absorption spectra of oxidized macroporous silicon were studied. • The Wannier–Stark electro-optical effect on Si-SiO_2 boundary was confirmed. • An additional electric field of quasi-guided optical modes was evaluated. • The photonic modes and band gaps were measured as peculiarities in absorption spectra. - Abstract: Opportunities to enhance the properties of structured surfaces were demonstrated on 2D macroporous silicon structures with SiO_2 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-SiO_2boundary 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 SiO_2 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.

  19. Preparation of three-dimensional macroporous chitosan-gelatin B microspheres and HepG2-cell culture.

    Science.gov (United States)

    Huang, Fang; Cui, Long; Peng, Cheng-Hong; Wu, Xu-Bo; Han, Bao-San; Dong, Ya-Dong

    2016-12-01

    Chitosan-gelatin B microspheres with an open, interconnected, highly macroporous (100-200 µm) structure were prepared via a three-step protocol combining freeze-drying with an electrostatic and ionic cross-linking method. Saturated tripolyphosphate ethanol solution (85% ethanol) was chosen as the crosslinking agent to prevent destruction of the porous structure and to improve the biostability of the chitosan-gelatin B microspheres, with N-(3-dimethylaminopropyl)-N'-ethyl-carbodiimide/N-hydroxysuccinimide as a second crosslinking agent to react with gelatin A and fixed chitosan-gelatin B microspheres to attain improved biocompatibility. Water absorption of the three-dimensional macroporous chitosan-gelatin B microspheres (3D-P-CGMs) was 12.84, with a porosity of 85.45%. In vitro lysozyme degradation after 1, 3, 5, 7, 10, 14, and 21 days showed improved biodegradation in the 3D-P-CGMs. The morphology of human hepatoma cell lines (HepG2 cells) cultured on the 3D-P-CGMs was spherical, unlike that of cells cultured under traditional two-dimensional conditions. Scanning electron microscopy and paraffin sections were used to confirm the porous structure of the 3D-P-CGMs. HepG2 cells were able to migrate inside through the pore. Cell proliferation and levels of albumin and lactate dehydrogenase suggested that the 3D-P-CGMs could provide a larger specific surface area and an appropriate microenvironment for cell growth and survival. Hence, the 3D-P-CGMs are eminently suitable as macroporous scaffolds for cell cultures in tissue engineering and cell carrier studies. Copyright © 2014 John Wiley & Sons, Ltd. Copyright © 2014 John Wiley & Sons, Ltd.

  20. 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...... activity for methane combustion, which derived from the MTMP providing a larger surface area and pore volume, uniform pore sizes, higher accessible surface oxygen concentration, better low-temperature reducibility, and a unique nanovoid 3D structure....

  1. Effects of CT Number-Derived Matrix Density on Preferential Flow 1 and Transport in a Macroporous Agricultural Soil

    DEFF Research Database (Denmark)

    Katuwal, Sheela; Moldrup, Per; Lamandé, Mathieu

    2015-01-01

    risks to public health. This study was focused on establishing links between the structural pore space and preferential transport using a combination of standard physical measurement methods for air and water permeabilities, breakthrough experiments, and X-ray Computed Tomography (CT) on large soil...... columns. Substantial structural heterogeneity that resulted in significant variations of flow and tracer transport was observed, despite the textural similarity of investigated samples. Quantification of macropore characteristics with X-ray CT was useful but not sufficient to explain the variability...

  2. Study of Ni Metallization in Macroporous Si Using Wet Chemistry for Radio Frequency Cross-Talk Isolation in Mixed Signal Integrated Circuits.

    Science.gov (United States)

    Zhang, Xi; Xu, Chengkun; Chong, Kyuchul; Tu, King-Ning; Xie, Ya-Hong

    2011-05-25

    A highly conductive moat or Faraday cage of through-the-wafer thickness in Si substrate was proposed to be effective in shielding electromagnetic interference thereby reducing radio frequency (RF) cross-talk in high performance mixed signal integrated circuits. Such a structure was realized by metallization of selected ultra-high-aspect-ratio macroporous regions that were electrochemically etched in p - Si substrates. The metallization process was conducted by means of wet chemistry in an alkaline aqueous solution containing Ni 2+ without reducing agent. It is found that at elevated temperature during immersion, Ni 2+ was rapidly reduced and deposited into macroporous Si and a conformal metallization of the macropore sidewalls was obtained in a way that the entire porous Si framework was converted to Ni. A conductive moat was as a result incorporated into p - Si substrate. The experimentally measured reduction of crosstalk in this structure is 5~18 dB at frequencies up to 35 GHz.

  3. Study of Ni Metallization in Macroporous Si Using Wet Chemistry for Radio Frequency Cross-Talk Isolation in Mixed Signal Integrated Circuits

    Science.gov (United States)

    Zhang, Xi; Xu, Chengkun; Chong, Kyuchul; Tu, King-Ning; Xie, Ya-Hong

    2011-01-01

    A highly conductive moat or Faraday cage of through-the-wafer thickness in Si substrate was proposed to be effective in shielding electromagnetic interference thereby reducing radio frequency (RF) cross-talk in high performance mixed signal integrated circuits. Such a structure was realized by metallization of selected ultra-high-aspect-ratio macroporous regions that were electrochemically etched in p− Si substrates. The metallization process was conducted by means of wet chemistry in an alkaline aqueous solution containing Ni2+ without reducing agent. It is found that at elevated temperature during immersion, Ni2+ was rapidly reduced and deposited into macroporous Si and a conformal metallization of the macropore sidewalls was obtained in a way that the entire porous Si framework was converted to Ni. A conductive moat was as a result incorporated into p− Si substrate. The experimentally measured reduction of crosstalk in this structure is 5~18 dB at frequencies up to 35 GHz. PMID:28879960

  4. Porphyrinic metal-organic framework/macroporous carbon composites for electrocatalytic applications

    International Nuclear Information System (INIS)

    Yin, Duanduan; Liu, Jian; Bo, Xiangjie; Li, Mian; Guo, Liping

    2017-01-01

    Graphical abstract: Zr-PorMOF/MPC composites were prepared, which used to detect H 2 O 2 and simultaneously detect UA, XA and HX Display Omitted -- Highlights: •Preparing Zr-PorMOF/MPC composites by a simple one-step solvothermal reaction. •Enhanced electrocatalytic activity at Zr-PorMOF/MPC than Zr-PorMOF and MPC. •A low detection limit, short response time and low applied potential towards H 2 O 2 reduction. •Simultaneous determination of UA, XA and HX. -- Abstract: In this work, a novel porphyrinic metal-organic framework-based composite has been successfully synthesized by a simple one-step solvothermal method through growing Zr-PorMOF on macroporous carbon (MPC). Porphyrin-base MOFs combining the structural adjustable of MOFs and the specific catalytic activity of biomimetic catalysts play an important role in electrocatalysis. A series of characterization show that the roles of MPC as follow: (1) MPC could avoid the agglomeration of Zr-PorMOF particles and increase the specific surface area; (2) MPC could improve the electrochemical stability of Zr-PorMOF particles; (3) MPC could reduce the electron transfer resistance. Therefore, MPC plays the role of the conductive bridges to provide facile charge transport. The obtained Zr-PorMOF/MPC composites exhibit much better electrocatalytic activity for the reduction of hydrogen peroxide (H 2 O 2 ) than the pristine Zr-PorMOF due to the synergy of Zr-PorMOF and MPC. This enzyme-free H 2 O 2 sensor shows two linear relationships in the ranges 0.5–137 μM (R 2 = 0.991, sensitivity = 66 μA mM −1 ) and 137–3587 μM (R 2 = 0.993, sensitivity = 16 μA mM −1 ), with a low over-potential at −0.2 V, a fast response time within 1 s and a low limit of detection (LOD) of 0.18 μM. Moreover, Zr-PorMOF/MPC composites were used to simultaneously detect uric acid (UA), xanthine (XA) and hypoxanthine (HX). These three substances are degradation products of purine metabolism. In addition, Zr-PorMOF/MPC composites

  5. Monolithic poly(1,2-bis(p-vinylphenyl)ethane) capillary columns for simultaneous separation of low- and high-molecular-weight compounds.

    Science.gov (United States)

    Greiderer, Andreas; Ligon, S Clark; Huck, Christian W; Bonn, Günther K

    2009-08-01

    Monolithic poly(1,2-bis(p-vinylphenyl)ethane (BVPE)) capillary columns were prepared by thermally initiated free radical polymerisation of 1,2-bis(p-vinylphenyl)ethane in the presence of inert diluents (porogens) and alpha,alpha'-azoisobutyronitrile (AIBN) as initiator. Polymerisations were accomplished in 200 microm ID fused silica capillaries at 65 degrees C and for 60 min. Mercury intrusion porosimetry measurements of the polymeric RP support showed a broad bimodal pore-size-distribution of mesopores and small macropores in the range of 5-400 nm and flow-channels in the mum range. N(2)-adsorption (BET) analysis resulted in a tremendous enhancement of surface area (101 m(2)/g) of BVPE stationary phases compared to typical organic monoliths (approximately 20 m(2)/g), indicating the presence of a considerable amount of mesopores. Consequently, the adequate proportion of both meso- and (small) macropores allowed the rapid and high-resolution separation of low-molecular-weight compounds as well as biomolecules on the same monolithic support. At the same time, the high fraction of flow-channels provided enhanced column permeability. The chromatographic performance of poly(1,2-bis(p-vinylphenyl)ethane) capillary columns for the separation of biomolecules (proteins, oligonucleotides) and small molecules (alkyl benzenes, phenols, phenons) are demonstrated in this article. Additionally, pressure drop versus flow rate measurements of novel poly(1,2-bis(p-vinylphenyl)ethane) capillary columns confirmed high mechanical robustness, low swelling in organic solvents and high permeability. Due to the simplicity of monolith fabrication, comprehensive studies of the retention and separation behaviour of monolithic BVPE columns resulted in high run-to-run and batch-to-batch reproducibilities. All these attributes prove the excellent applicability of monolithic poly(1,2-bis(p-vinylphenyl)ethane) capillary columns for micro-HPLC towards a huge range of analytes of different

  6. Negative plate macropore surfaces in lead-acid batteries: Porosity, Brunauer-Emmett-Teller area, and capacity

    Energy Technology Data Exchange (ETDEWEB)

    D' Alkaine, C.V.; de O. Brito, G.A. [Group of Electrochemistry and Polymers, DQ-UFSCar, Rodovia Washington Luis, Km 235, CP 676, 13565-905 Sao Carlos (SP) (Brazil)

    2009-06-01

    We propose an explanation for the production of an electrochemically active area during the electrochemical formation of lead-acid battery negative plates based on solid-state reactions. Our proposal is supported by experimental data. This study includes a critical review of the literature on charge/discharge mechanisms, porosity, and BET area. The critical review, through the latter two parameters, indicates the existence of both macro and micropores in positive plates, but only macropores in negative plates, with characteristic surface roughness. In the present paper the surface sulfation of the precursor is controlled using various acidic, neutral and alkaline solutions during an electrochemical formation process that does not include soaking. Our results confirm that variable roughness can be produced at the negative plate macropore surfaces. The morphological changes produced by different formation conditions are assessed by measuring the macroporosity, BET area, and capacity of single negative plates. Based on these concepts, a method was developed and applied to measure independently the contributions of geometrical surface macroporosity and roughness to the negative plate capacity. (author)

  7. Studies on the absorption of uranium and plutonium on macroporous anion-exchange resins from mixed solvent media

    International Nuclear Information System (INIS)

    Chetty, K.V.; Mapara, P.M.; Godbole, A.G.; Swarup, Rajendra

    1995-01-01

    The ion-exchange studies on uranium and plutonium using macroporous anion-exchange resins from an aqueous-organic solvent mixed media were carried out to develop a method for their separation. Out of the several water miscible organic solvents tried, methanol and acetone were found to be best suited. Distribution data for U(VI) and Pu(IV) for three macroporous resins Tulsion A-27(MP) (strong base), Amberlyst A-26(MP) (strong base) and Amberlite XE-270(MP) (weak base) as a function of (i) nitric acid concentration (ii) organic solvent concentration were obtained. Based on the data separation factors for Pu/U were calculated. Column experiments using Tulsion A-27(MP) from a synthetic feed (HNO 3 - methanol and HNO 3 - acetone) containing Pu and U in different ratios were carried out. Plutonium was recovered from the bulk of the actual solution generated during the dissolution of plutonium bearing fuels. The method has the advantage of loading plutonium from as low as 1M nitric acid in presence of methanol or acetone and could be used satisfactorily for its recovery from solutions containing plutonium and uranium. (author). 11 refs., 4 figs., 16 tabs

  8. Molecularly imprinted macroporous monoliths for solid-phase extraction: Effect of pore size and column length on recognition properties.

    Science.gov (United States)

    Vlakh, E G; Stepanova, M A; Korneeva, Yu M; Tennikova, T B

    2016-09-01

    The series of macroporous monolithic molecularly imprinted monoliths differed by pore size, column length (volume) and amount of template used for imprinting was synthesized using methacrylic acid and glycerol dimethacrylate as co-monomers and antibiotic ciprofloxacin as a template. The prepared monoliths were characterized regarding to their permeability, pore size, porosity, and resistance to the flow of a mobile phase. The surface morphology was also analyzed. The slight dependence of imprinting factor on flow rate, as well as its independence on pore size of macroporous molecularly imprinted monolithic media was observed. The column obtained at different conditions exhibited different affinity of ciprofloxacin to the imprinted sites that was characterized with Kdiss values in the range of 10(-5)-10(-4)M. The solid-phase extraction of ciprofloxacin from such biological liquids as human blood serum, human urine and cow milk serum was performed using the developed monolithic columns. In all cases, the extraction was found to be 95.0-98.6%. Additionally, the comparison of extraction of three fluoroqinolone analogues, e.g. ciprofloxacin, levofloxacin and moxifloxacin, from human blood plasma was carried out. Contrary to ciprofloxacin extracted with more than 95%, this parameter did not exceed 40% for its analogues. Copyright © 2016 Elsevier B.V. All rights reserved.

  9. Adsorption and desorption properties of macroporous resins for anthocyanins from the calyx extract of roselle (Hibiscus sabdariffa L.).

    Science.gov (United States)

    Chang, Xiu-Lian; Wang, Dong; Chen, Bi-Yun; Feng, Yong-Mei; Wen, Shao-Hong; Zhan, Peng-Yuan

    2012-03-07

    Adsorption of roselle anthocynins, a natural pigment, onto various macroporous resins was optimized to develop a simple and efficient process for industrial separation and purification of roselle anthocyanins. Nine different macroporous resins (AB-8, X-5, HPD-100, SP-207, XAD-4, LS-305A, DM-21, LS-610B, and LS-305) were evaluated for the adsorption properties of the anthocyanins extracted from the calyx extract of Hibiscus sabdariffa L. The influences of phase contact time, solution pH, initial anthocyanin concentration, and ethanol concentration with different citric acid amounts were studied by the static adsorption/desorption method. The adsorption isotherm data were fitted well to the Langmuir isotherm, and according to this model, LS-610B and LS-305 exhibited the highest monolayer sorption capacities of 31.95 and 38.16 mg/g, respectively. The kinetic data were modeled using pseudo-first-order, pseudo-second-order, and intraparticle diffusion equations. The experimental data were well described by the pseudo-second-order kinetic model. Continuous column adsorption-regeneration cycles indicated negligible capacity loss of LS-305 during operation. The overall yield of pigment product was 49.6 mg/g dried calyces. The content of roselle anthocynins in the pigment product was 4.85%.

  10. Surface plasmon resonance sensor for femtomolar detection of testosterone with water-compatible macroporous molecularly imprinted film.

    Science.gov (United States)

    Zhang, Qingwen; Jing, Lijing; Zhang, Jinling; Ren, Yamin; Wang, Yang; Wang, Yi; Wei, Tianxin; Liedberg, Bo

    2014-10-15

    A novel water-compatible macroporous molecularly imprinted film (MIF) has been developed for rapid, sensitive, and label-free detection of small molecule testosterone in urine. The MIF was synthesized by photo copolymerization of monomers (methacrylic acid [MAA] and 2-hydroxyethyl methacrylate [HEMA]), cross-linker (ethylene glycol dimethacrylate, EGDMA), and polystyrene nanoparticles (PS NPs) in combination with template testosterone molecules. The PS NPs and template molecules were subsequently removed to form an MIF with macroporous structures and the specific recognition sites of testosterone. Incubation of artificial urine and human urine on the MIF and the non-imprinted film (NIF), respectively, indicated undetectable nonspecific adsorption. Accordingly, the MIF was applied on a surface plasmon resonance (SPR) sensor for the detection of testosterone in phosphate-buffered saline (PBS) and artificial urine with a limit of detection (LOD) down to 10(-15)g/ml. To the best of our knowledge, the LOD is considered as one of the lowest among the SPR sensors for the detection of small molecules. The control experiments performed with analogue molecules such as progesterone and estradiol demonstrated the good selectivity of this MIF for sensing testosterone. Furthermore, this MIF-based SPR sensor shows high stability and reproducibility over 8months of storage at room temperature, which is more robust than protein-based biosensors. Copyright © 2014 Elsevier Inc. All rights reserved.

  11. Separation and purification of both tea seed polysaccharide and saponin from camellia cake extract using macroporous resin.

    Science.gov (United States)

    Yang, Pengjie; Zhou, Mingda; Zhou, Chengyun; Wang, Qian; Zhang, Fangfang; Chen, Jian

    2015-02-01

    A novel method to separate and purify tea seed polysaccharide and tea seed saponin from camellia cake extract by macroporous resin was developed. Among four kinds of resins (AB-8, NKA-9, XDA-6, and D4020) tested, AB-8 macroporous resin possessed optimal separating capacity for the two substances and thus was selected for the separation, in which deionized water was used to elute tea seed polysaccharide, 0.25% NaOH solution to remove the undesired pigments, and 90% ethanol to elute tea seed saponin. Further dynamic adsorption/desorption experiments on AB-8 resin-based column chromatography were conducted to obtain the optimal parameters. Under optimal dynamic adsorption and desorption conditions, 18.7 and 11.8% yield of tea seed polysaccharide and tea seed saponin were obtained with purities of 89.2 and 96.0%, respectively. The developed method provides a potential approach for the large-scale production of tea seed polysaccharide and tea seed saponin from camellia cake. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Self-floating carbon nanotube membrane on macroporous silica substrate for highly efficient solar-driven interfacial water evaporation

    KAUST Repository

    Wang, Yuchao

    2016-01-22

    Given the emerging energy and water challenges facing the mankind, solar-driven water evaporation has been gaining renewed research attention from both academia and industry as an energy efficient means of wastewater treatment and clean water production. In this project, a bi-layered material, consisting of a top self-floating hydrophobic CNT membrane and a bottom hydrophilic macroporous silica substrate, was rationally designed and fabricated for highly energy-efficient solar driven water evaporation based on the concept of interfacial heating. The top thin CNT membrane with excellent light adsorption capability, acted as photothermal component, which harvested and converted almost the entire incident light to heat for exclusively heating of interfacial water. On the other hand, the macroporous silica substrate provided multi-functions toward further improvement of operation stability and water evaporation performance of the material, including water pumping, mechanical support and heat barriers. The silica substrate was conducive in forming the rough surface structures of the CNT top layers during vacuum filtration and thus indirectly contributed to high light adsorption by the top CNT layers. With optimized thicknesses of the CNT top layer and silica substrate, a solar thermal conversion efficiency of 82 % was achieved in this study. The bi-layered material also showed great performance toward water evaporation from seawater and contaminated water, realizing the separation of water from pollutants, and indicating its application versatility.

  13. Mechanosensation across borders: fibroblasts inside a macroporous scaffold sense and respond to the mechanical environment beyond the scaffold walls.

    Science.gov (United States)

    Könnig, D; Herrera, A; Duda, G N; Petersen, A

    2018-01-01

    In tissue defects, cells face distinct mechanical boundary conditions, but how this influences early stages of tissue regeneration remains largely unknown. Biomaterials are used to fill defects but also to provide specific mechanical or geometrical signals. However, they might at the same time shield mechanical information from surrounding tissues that is relevant for tissue functionalisation. This study investigated how fibroblasts in a soft macroporous biomaterial scaffold respond to distinct mechanical environments while they form microtissues. Different boundary stiffnesses counteracting scaffold contraction were provided via a newly developed in vitro setup. Online monitoring over 14 days revealed 3.0 times lower microtissue contraction but 1.6 times higher contraction force for high vs. low stiffness. This difference was significant already after 48 h, a very early stage of microtissue growth. The microtissue's mechanical and geometrical adaptation indicated a collective cellular behaviour and mechanical communication across scaffold pore walls. Surprisingly, the stiffness of the environment influenced cell behaviour even inside macroporous scaffolds where direct cell-cell contacts are hindered. Mechanical communication between cells via traction forces is essential for tissue adaptation to the environment and should not be blocked by rigid biomaterials. Copyright © 2017 John Wiley & Sons, Ltd. Copyright © 2017 John Wiley & Sons, Ltd.

  14. The influence of plutonium concentration and solution flow rate on the effective capacity of macroporous anion exchange resin

    International Nuclear Information System (INIS)

    Marsh, S.F.; Gallegos, T.D.

    1987-07-01

    The principal aqueous process used to recover and purify plutonium at the Los Alamos Plutonium Facility is anion exchange in nitric acid. Previous studies with gel-type anion exchange resin have shown an inverse relationship between plutonium concentration in the feed solution and the optimum flow rate for this process. Because gel-type resin has been replaced with macroporous resin at Los Alamos, the relationship between plutonium concentration and solution flow rate was reexamined with the selected Lewatit MP-500-FK resin using solutions of plutonium in nitric acid and in nitric acid with high levels of added nitrate salts. Our results with this resin differ significantly from previous data obtained with gel-type resin. Flow-rate variation from 10 to 80 liters per hour had essentially no effect on the measured quantities of plutonium sorbed by the macroporous resin. However, the effect of plutonium concentration in the feed solutions was pronounced, as feed solutions that contained the highest concentrations of plutonium also produced the highest resin loadings. The most notable effect of high concentrations of dissolved nitrate salts in these solutions was an increased resin capacity for plutonium at low flow rates. 16 refs., 7 figs., 2 tabs

  15. Self-floating carbon nanotube membrane on macroporous silica substrate for highly efficient solar-driven interfacial water evaporation

    KAUST Repository

    Wang, Yuchao; Zhang, Lianbin; Wang, Peng

    2016-01-01

    Given the emerging energy and water challenges facing the mankind, solar-driven water evaporation has been gaining renewed research attention from both academia and industry as an energy efficient means of wastewater treatment and clean water production. In this project, a bi-layered material, consisting of a top self-floating hydrophobic CNT membrane and a bottom hydrophilic macroporous silica substrate, was rationally designed and fabricated for highly energy-efficient solar driven water evaporation based on the concept of interfacial heating. The top thin CNT membrane with excellent light adsorption capability, acted as photothermal component, which harvested and converted almost the entire incident light to heat for exclusively heating of interfacial water. On the other hand, the macroporous silica substrate provided multi-functions toward further improvement of operation stability and water evaporation performance of the material, including water pumping, mechanical support and heat barriers. The silica substrate was conducive in forming the rough surface structures of the CNT top layers during vacuum filtration and thus indirectly contributed to high light adsorption by the top CNT layers. With optimized thicknesses of the CNT top layer and silica substrate, a solar thermal conversion efficiency of 82 % was achieved in this study. The bi-layered material also showed great performance toward water evaporation from seawater and contaminated water, realizing the separation of water from pollutants, and indicating its application versatility.

  16. Transport properties of poly(GACT)–poly(CTGA)

    Indian Academy of Sciences (India)

    In this paper, based on the tight-binding Hamiltonian model and within the framework of a generalized Green's function technique, the electronic conduction through the poly(GACT)–poly(CTGA) DNA molecule in SWNT/DNA/SWNT structure has been numerically investigated. In a ladder model, we consider DNA as a ...

  17. Wiping frictional properties of electrospun hydrophobic/hydrophilic polyurethane nanofiber-webs on soda-lime glass and silicon-wafer.

    Science.gov (United States)

    Watanabe, Kei; Wei, Kai; Nakashima, Ryu; Kim, Ick Soo; Enomoto, Yuji

    2013-04-01

    In the present work, we conducted the frictional tests of hydrophobic and hydrophilic polyurethane (PUo and PUi) nanofiber webs against engineering materials; soda-lime glass and silicon wafer. PUi/glass combination, with highest hydrophilicity, showed the highest friction coefficient which decrease with the increase of the applied load. Furthermore, the effects of fluorine coating are also investigated. The friction coefficient of fluorine coated hydrophobic PU nanofiber (PUof) shows great decrease against the silicon wafer. Finally, wiping ability and friction property are investigated when the substrate surface is contaminated. Nano-particle dusts are effectively collected into the pores by wiping with PUo and PUi nanofiber webs both on glass and silicon wafer. The friction coefficient gradually increased with the increase of the applied load.

  18. Efficient "on-the-fly" calculation of Raman spectra from ab-initio molecular dynamics: Application to hydrophobic/hydrophilic solutes in bulk water.

    Science.gov (United States)

    Partovi-Azar, Pouya; Kühne, Thomas D

    2015-11-05

    We present a novel computational method to accurately calculate Raman spectra from first principles. Together with an extension of the second-generation Car-Parrinello method of Kühne et al. (Phys. Rev. Lett. 2007, 98, 066401) to propagate maximally localized Wannier functions together with the nuclei, a speed-up of one order of magnitude can be observed. This scheme thus allows to routinely calculate finite-temperature Raman spectra "on-the-fly" by means of ab-initio molecular dynamics simulations. To demonstrate the predictive power of this approach we investigate the effect of hydrophobic and hydrophilic solutes in water solution on the infrared and Raman spectra. © 2015 Wiley Periodicals, Inc.

  19. Solar CalPoly

    Energy Technology Data Exchange (ETDEWEB)

    Stannard, Sandra [California Polytechnic State Univ., San Luis Obispo, CA (United States)

    2016-06-15

    The target budget of INhouse was about $650,000 for all materials and student expenses of the Solar Decathlon competition. In order to reach our goal, Cal Poly students and faculty worked with the College of Architecture and Environmental Design’s External Relations office to actively fundraise for INhouse. Students connected with Cal Poly alumni through phone calls, postal mail, email, and live presentations to reach as many alumni in the state of California as possible. Before construction begun, students and faculty met on a weekly basis to determine what brands of materials for the home to use and who would be responsible for reaching out to the company to seek a donation. Our College of Architecture and Environmental Design’s administration was essential in helping us fundraise. For some time, the college was hoping to depend on about half of our fundraising expenses to be covered through the sale of INhouse. However, plans to sell the home fell through during the design development phase; the college turned to the sale of a different asset in to help us meet our goal. If we were to do this project again, completing the design concept and securing a future location of our home sooner would have enhanced our fundraising activities.

  20. Poly(alkyl acrylate) nonparticles

    International Nuclear Information System (INIS)

    Kreuter, J.

    1985-01-01

    This study deals with the preparation of poly(alkyl acrylic) and poly(alkyl cyanocrylic) nanoparticles. Nonoparticles are solid colloidal particles, consisting of macromolecular materials in which drugs or biologically active materials are dissolved, entrapped, and encapsulated, and/or to which the active substance is adsorbed or attached. Poly(alkyl acrylic) nanoparticles are much more slowly biodegradable than poly(alkyl cyanoacrylate) nanoparticles, and are thus more suitable for drug delivery purposes. Poly(methyl methacrylate) is the material of choice for the use of nanoparticles as an adjuvant for vaccines and are produced by emulsifier-free polymerization in aqueous media. The polymerization, which can be initiated with gamma rays or with potassium peroxodisulfate, is described

  1. Facile synthesis of radial-like macroporous superparamagnetic chitosan spheres with in-situ co-precipitation and gelation of ferro-gels.

    Directory of Open Access Journals (Sweden)

    Chih-Hui Yang

    Full Text Available Macroporous chitosan spheres encapsulating superparamagnetic iron oxide nanoparticles were synthesized by a facile and effective one-step fabrication process. Ferro-gels containing ferrous cations, ferric cations and chitosan were dropped into a sodium hydroxide solution through a syringe pump. In addition, a sodium hydroxide solution was employed for both gelation (chitosan and co-precipitation (ferrous cations and ferric cations of the ferro-gels. The results showed that the in-situ co-precipitation of ferro-ions gave rise to a radial morphology with non-spheroid macro pores (large cavities inside the chitosan spheres. The particle size of iron oxide can be adjusted from 2.5 nm to 5.4 nm by tuning the concentration of the sodium hydroxide solution. Using Fourier Transform Infrared Spectroscopy and X-ray diffraction spectra, the synthesized nanoparticles were illustrated as Fe(3O(4 nanoparticles. In addition, the prepared macroporous chitosan spheres presented a super-paramagnetic behaviour at room temperature with a saturation magnetization value as high as ca. 18 emu/g. The cytotoxicity was estimated using cell viability by incubating doses (0∼1000 µg/mL of the macroporous chitosan spheres. The result showed good viability (above 80% with alginate chitosan particles below 1000 µg/mL, indicating that macroporous chitosan spheres were potentially useful for biomedical applications in the future.

  2. Amperometric carbohydrate antigen 19-9 immunosensor based on three dimensional ordered macroporous magnetic Au film coupling direct electrochemistry of horseradish peroxidase

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Qi [College of Sciences, Nanjing Tech University, Nanjing 211816 (China); Chen, Xiaojun, E-mail: chenxj_njut@126.com [College of Sciences, Nanjing Tech University, Nanjing 211816 (China); State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing Tech University, Nanjing 210009 (China); Tang, Yin [Zhangjiagang Hospital of Traditional Chinese Medicine, Zhangjiagang 215600 (China); Ge, Lingna; Guo, Buhua [College of Sciences, Nanjing Tech University, Nanjing 211816 (China); Yao, Cheng, E-mail: yaochengnjut@163.com [College of Sciences, Nanjing Tech University, Nanjing 211816 (China)

    2014-03-01

    Highlights: • Three dimensional ordered macroporous magnetic electrode was newly used in electrochemical immunosensor. • The large surface area of macroporous magnetic electrode could improve the immobilized amount of antibody. • Au nanoparticles functionalized SBA-15 was used to immobilize enzyme labeled Ab₂ and enzyme. • Macroporous magnetic electrode and Au nanoparticles composite facilitated the direct electron transfer of enzyme. • The immunoassay avoided adding electron transfer mediator, simplifying the procedure. Abstract: A sandwich-type electrochemical immunosensor for the detection of carbohydrate antigen 19-9 (CA 19-9) antigen based on the immobilization of primary antibody (Ab₁) on three dimensional ordered macroporous magnetic (3DOMM) electrode, and the direct electrochemistry of horseradish peroxidase (HRP) that was used as both the label of secondary antibody (Ab₂) and the blocking reagent. The 3DOMM electrode was fabricated by introducing core–shell Au–SiO₂@Fe₃O₄ nanospheres onto the surface of three dimensional ordered macroporous (3DOM) Au electrode via the application of an external magnet. Au nanoparticles functionalized SBA-15 (Au@SBA-15) was conjugated to the HRP labeled secondary antibody (HRP-Ab₂) through the Au–SH or Au–NH₃⁺ interaction, and HRP was also used as the block reagent. The formation of antigen–antibody complex made the combination of Au@SBA-15 and 3DOMM exhibit remarkable synergistic effects for accelerating direct electron transfer (DET) between HRP and the electrode. Under the optimal conditions, the DET current signal increased proportionally to CA 19-9 concentration in the range of 0.05 to 15.65 U mL⁻¹ with a detection limit of 0.01 U mL⁻¹. Moreover, the immunosensor showed high selectivity, good stability, satisfactory reproducibility and regeneration. Importantly, the developed method was used to assay clinical serum specimens, achieving a good relation with those obtained from

  3. A simple and effective approach to prepare injectable macroporous calcium phosphate cement for bone repair: Syringe-foaming using a viscous hydrophilic polymeric solution.

    Science.gov (United States)

    Zhang, Jingtao; Liu, Weizhen; Gauthier, Olivier; Sourice, Sophie; Pilet, Paul; Rethore, Gildas; Khairoun, Khalid; Bouler, Jean-Michel; Tancret, Franck; Weiss, Pierre

    2016-02-01

    In this study, we propose a simple and effective strategy to prepare injectable macroporous calcium phosphate cements (CPCs) by syringe-foaming via hydrophilic viscous polymeric solution, such as using silanized-hydroxypropyl methylcellulose (Si-HPMC) as a foaming agent. The Si-HPMC foamed CPCs demonstrate excellent handling properties such as injectability and cohesion. After hardening the foamed CPCs possess hierarchical macropores and their mechanical properties (Young's modulus and compressive strength) are comparable to those of cancellous bone. Moreover, a preliminary in vivo study in the distal femoral sites of rabbits was conducted to evaluate the biofunctionality of this injectable macroporous CPC. The evidence of newly formed bone in the central zone of implantation site indicates the feasibility and effectiveness of this foaming strategy that will have to be optimized by further extensive animal experiments. A major challenge in the design of biomaterial-based injectable bone substitutes is the development of cohesive, macroporous and self-setting calcium phosphate cement (CPC) that enables rapid cell invasion with adequate initial mechanical properties without the use of complex processing and additives. Thus, we propose a simple and effective strategy to prepare injectable macroporous CPCs through syringe-foaming using a hydrophilic viscous polymeric solution (silanized-hydroxypropyl methylcellulose, Si-HPMC) as a foaming agent, that simultaneously meets all the aforementioned aims. Evidence from our in vivo studies shows the existence of newly formed bone within the implantation site, indicating the feasibility and effectiveness of this foaming strategy, which could be used in various CPC systems using other hydrophilic viscous polymeric solutions. Copyright © 2015 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  4. Hollow hemisphere-shaped macroporous graphene/tungsten carbide/platinum nanocomposite as an efficient electrocatalyst for the oxygen reduction reaction

    International Nuclear Information System (INIS)

    Li, Zesheng; Liu, Zhisen; Li, Bolin; Liu, Zhenghui; Li, Dehao; Wang, Hongqiang; Li, Qingyu

    2016-01-01

    Graphical abstract: Newfashioned hollow hemisphere-shaped macroporous graphene/tungsten carbide/platinum (HMG/WC/Pt) nanocomposite with interesting three-dimensional architecture bas been successfully fabricated as an efficient electrocatalyst for the oxygen reduction reaction. - Highlights: • Hollow hemisphere-shaped macroporous graphene is proposed as ORR catalyst support. • Honeycomb-like macroporous graphene/WC/Pt electrocatalyst is firsy prepared for ORR. • The present electrocatalyst exhibited greatly enhanced ORR catalytic activity and stability. - Abstract: Hollow hemisphere-shaped macroporous graphene/tungsten carbide/platinum (HMG/WC/Pt) nanocomposite has been synthesized as an efficient electrocatalyst for the oxygen reduction reaction (ORR). The HMG/WC/Pt sample has been systematically characterized by the X-ray diffraction (XRD), Scanning electron microscope (SEM) and Transmission electron microscopy (TEM). The analysis results indicate that the sample has an interesting three-dimensional hollow hemisphere-shaped macroporous architecture. The results also demonstrate the successful integration of WC and Pt nanoparticles on the HMG, in which the WC nanoparticles are in size of about 10 nm and the Pt nanoparticles are in size of about 3 nm. The as-prepared HMG/WC/Pt electrode displays excellent electrocatalytic performances for the ORR in 0.1 mol L −1 HClO 4 electrolyte. The mass activity (i m at 0.9 V) of HMG/WC/Pt is 206 mA mg −1 Pt, which is about 85% higher than that of Pt/C (112 mA mg −1 Pt). It also displayed a very high activity retention of 84.5% after 2000 cyclic voltammetry cycles for the HMG/WC/Pt, while that of the Pt/C is only 70.5%. The HMG/WC/Pt nanocomposite would be a promising electrocatalytic material for the ORR in Fuel cell applications.

  5. Three dimensional poly(ε-caprolactone) and silk fibroin nanocomposite fibrous matrix for artificial dermis

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jung Min, E-mail: yiyi1124@gmail.com [Nano-Bio Regenerative Medical Institute, College of Medicine, Hallym University, Chuncheon 200-702 (Korea, Republic of); Chae, Taesik, E-mail: apsiky@gmail.com [Department of Materials Engineering, University of British Columbia, Vancouver, BC V6T 1Z4 (Canada); Sheikh, Faheem A., E-mail: faheem99in@yahoo.com [Nano-Bio Regenerative Medical Institute, College of Medicine, Hallym University, Chuncheon 200-702 (Korea, Republic of); Ju, Hyung Woo, E-mail: anabasjoo@gmail.com [Nano-Bio Regenerative Medical Institute, College of Medicine, Hallym University, Chuncheon 200-702 (Korea, Republic of); Moon, Bo Mi, E-mail: toribom@gmail.com [Nano-Bio Regenerative Medical Institute, College of Medicine, Hallym University, Chuncheon 200-702 (Korea, Republic of); Park, Hyun Jung, E-mail: hyunjungpark869@gmail.com [Nano-Bio Regenerative Medical Institute, College of Medicine, Hallym University, Chuncheon 200-702 (Korea, Republic of); Park, Ye Ri, E-mail: payeri89@gmail.com [Nano-Bio Regenerative Medical Institute, College of Medicine, Hallym University, Chuncheon 200-702 (Korea, Republic of); Park, Chan Hum, E-mail: hlpch@paran.com [Nano-Bio Regenerative Medical Institute, College of Medicine, Hallym University, Chuncheon 200-702 (Korea, Republic of); Department of Otorhinolaryngology-Head and Neck Surgery, School of Medicine, Hallym University, Chuncheon 200-704 (Korea, Republic of)

    2016-11-01

    Ideal dermal substitutes should have comparable physicochemical and biological properties to the natural skin tissue. In this study, we report a novel strategy to “engineer” controlled 3D nanocomposite fibrous matrix of poly(ε-caprolactone) (PCL) and silk fibroin (SF) for an artificial dermis application. Using a custom-designed cold-plate electrospinning and automatic magnet agitation system, up to 6 mm of the thickness was achieved resulting from the accumulation of ice crystal layers on the PCL nanofibers surface-modified with the SF particles. The sacrificed ice crystals induced interconnected macro-pores ranging from tens to hundreds μm. The agitation system introduced uniform distribution of the SF protein within/on the nanofibers, preventing the particles from precipitation and agglomeration. NIH 3T3 fibroblasts proliferated in vitro on the PCL and PCL/SF scaffolds for 7 days, but there was no statistical difference between the groups. Conversely, In vivo rat model studies revealed that the wound healing rate and collagen deposition increased with the SF content within the nanocomposites. The unique 3D construct with the PCL/SF nanocomposite fibers provided desirable spatial cues, surface topography, and surface chemistry for the native cells to infiltrate into the scaffolds. The wound healing potential of the nanocomposites was comparable to the commercial Matriderm® artificial dermis. - Highlights: • 3D macro-porous tissue engineering scaffold constructed with PCL nanofibers and SF nanoparticles. • Fabrication of the PCL/SF nanocomposite fibrous scaffold via a custom-designed cold plate electrospinning (CPE) and automatic magnet agitation (AMA) system. • Comparable wound healing capacity of the PCL/SF scaffolds to the commercial Matriderm® artificial dermis.

  6. Clay nanoparticles effects on performance and morphology of poly(vinylidene fluoride membranes

    Directory of Open Access Journals (Sweden)

    A. C. D. Morihama

    2014-03-01

    Full Text Available In this study, a comparison between neat poly(vinylidene fluoride (PVDF membrane and composite (PVDF-Nanoclay and PVDF-PVP-Nanoclay membranes is presented. All membranes were synthesized by the phase inversion process, using 18% PVDF, n-methylpyrrolidone as solvent and water as the non-solvent. Demineralized water cross-flow permeation tests were conducted to evaluate the membranes performance. Scanning electron microscopy (SEM images of the membranes surface and cross-section and water contact angle measurements were used to estimate additives effects on membranes morphology. The results indicate that dopant addition affected membrane permeate flux and morphology. The 4% nanoclay composite membrane resulted in the highest ultrapure water permeability (0.9130 m³.m-2.h-1.MPa-1, lower hydraulic resistance (3.27´10+12.m-1, lower contact angle (87.1º and highest surface porosity (0.95%. Furthermore, it was verified that the membrane surface porosity increased with increasing clay nanoparticles concentrations. It was observed that the morphology of the membranes with clay nanoparticle addition is characterized by a thin surface layer, with macro-pores, a thin bottom layer, which has a sponge-like structure with micro-pores and a thick intermediate layer, with finger-like pores and macro-pores. It was also verified that the introduction of PVP promotes a denser morphology compared with membranes without it. Based on the SEM surface and cross-sectional images and permeability tests, it became evident that the internal pore morphology plays an important role in membrane performance, because the higher the frequency and extent of the finger-like pores in the intermediate layer the higher is the membrane permeability. These preliminary results indicated that the use of nanoclay as an additive for membrane casting is a promising procedure for improving membrane performance for water and wastewater treatment.

  7. 1-Butanol absorption in poly(styrene-divinylbenzene) ion exchange resins for catalysis.

    Science.gov (United States)

    Pérez-Maciá, M A; Curcó, D; Bringué, R; Iborra, M; Rodríguez-Ropero, F; van der Vegt, N F A; Aleman, Carlos

    2015-12-21

    The swelling behaviour of poly(styrene-co-divinylbenzene), P(S-DVB), ion exchange resins in 1-butanol (BuOH) has been studied by means of atomistic classical molecular dynamics simulations (MD). The topological characteristics reported for the resin in the dry state, which exhibited complex internal loops (macropores), were considered for the starting models used to examine the swelling induced by BuOH contents ranging from 10% to 50% w/w. Experimental measurements using a laser diffraction particle size analyzer indicate that swelling causes a volume variation with respect to the dry resin of 21%. According to MD simulations, such a volume increment corresponds to a BuOH absorption of 31-32% w/w, which is in excellent agreement with the indirect experimental estimation (i.e. 31% w/w). Simulations reveal that, independently of the content of BuOH, the density of the swelled resin is higher than that of the dry resin, evidencing that the alcohol provokes important structural changes in the polymeric matrix. Thus, BuOH molecules cause a collapse of the resin macropores when the content of alcohol is ≤20% w/w. In contrast, when the concentration of BuOH is close to the experimental value (∼30% w/w), P(S-DVB) chains remain separated by pores faciliting the access of the reactants to the reaction centers. On the other hand, evaluation of both bonding and non-bonding interactions indicates that the mixing energy is the most important contribution to the absorption of BuOH into the P(S-DVB) resin. Overall, the results displayed in this work represent a starting point for the theoretical study of the catalytic conversion of BuOH into di-n-butyl ether in P(S-DVB) ion exchange resins using sophisticated electronic methods.

  8. Three dimensional poly(ε-caprolactone) and silk fibroin nanocomposite fibrous matrix for artificial dermis

    International Nuclear Information System (INIS)

    Lee, Jung Min; Chae, Taesik; Sheikh, Faheem A.; Ju, Hyung Woo; Moon, Bo Mi; Park, Hyun Jung; Park, Ye Ri; Park, Chan Hum

    2016-01-01

    Ideal dermal substitutes should have comparable physicochemical and biological properties to the natural skin tissue. In this study, we report a novel strategy to “engineer” controlled 3D nanocomposite fibrous matrix of poly(ε-caprolactone) (PCL) and silk fibroin (SF) for an artificial dermis application. Using a custom-designed cold-plate electrospinning and automatic magnet agitation system, up to 6 mm of the thickness was achieved resulting from the accumulation of ice crystal layers on the PCL nanofibers surface-modified with the SF particles. The sacrificed ice crystals induced interconnected macro-pores ranging from tens to hundreds μm. The agitation system introduced uniform distribution of the SF protein within/on the nanofibers, preventing the particles from precipitation and agglomeration. NIH 3T3 fibroblasts proliferated in vitro on the PCL and PCL/SF scaffolds for 7 days, but there was no statistical difference between the groups. Conversely, In vivo rat model studies revealed that the wound healing rate and collagen deposition increased with the SF content within the nanocomposites. The unique 3D construct with the PCL/SF nanocomposite fibers provided desirable spatial cues, surface topography, and surface chemistry for the native cells to infiltrate into the scaffolds. The wound healing potential of the nanocomposites was comparable to the commercial Matriderm® artificial dermis. - Highlights: • 3D macro-porous tissue engineering scaffold constructed with PCL nanofibers and SF nanoparticles. • Fabrication of the PCL/SF nanocomposite fibrous scaffold via a custom-designed cold plate electrospinning (CPE) and automatic magnet agitation (AMA) system. • Comparable wound healing capacity of the PCL/SF scaffolds to the commercial Matriderm® artificial dermis.

  9. Sonochemical synthesis and photocatalytic activity of meso- and macro-porous TiO2 for oxidation of toluene

    International Nuclear Information System (INIS)

    Yang Liu; Yan Li; Wang Yuntao; Xie Lei; Zheng Jie; Li Xingguo

    2008-01-01

    Meso-and macro-porous TiO 2 were synthesized by ultrasonic induced solvothermal method. Octadecylamine as a soft template was used to direct the formation of porous structure. The as-prepared porous TiO 2 was characterized by low angle and wide angle X-ray diffraction, N 2 adsorption-desorption isotherms and BET surface area. The energy influence of ultrasound and heat and concentration of nitric acid for post extraction on formation of porous structure were investigated. The photocatalytic activities of TiO 2 were investigated by degrading toluene gas under UV light. The results revealed that proper energy facilitates the formation of porous structure and too low concentration of nitric acid cannot extract template from pores. The photocatalytic activities of TiO 2 with porous structure are higher than those of nonporous ones

  10. Study of the structure of 3D-ordered macroporous GaN-ZnS:Mn nanocomposite films

    Energy Technology Data Exchange (ETDEWEB)

    Kurdyukov, D. A., E-mail: kurd@gvg.ioffe.ru; Shishkin, I. I.; Grudinkin, S. A.; Sitnikova, A. A.; Zamoryanskaya, M. V.; Golubev, V. G. [Russian Academy of Sciences, Ioffe Physical-Technical Institute (Russian Federation)

    2015-05-15

    A film-type 3D-ordered macroporous GaN-ZnS:Mn nanocomposite with the structure of an inverted opal is fabricated. Structural studies of the nanocomposite are performed, and it is shown that GaN and ZnS:Mn introduced into the pores of the silica opal are nanocrystallites misoriented with respect to each other. It is shown that the nanocomposite is a structurally perfect 3D photonic crystal. The efficiency of using a buffer of GaN crystallites to preclude interaction between the surface of the spherical a-SiO{sub 2} particles forming the opal matrix and chemically active substances introduced into the pores is demonstrated.

  11. Recovery of plutonium from nitric acid containing oxalate and fluoride by a macroporous bifunctional phosphinic acid resin (MPBPA)

    International Nuclear Information System (INIS)

    Venugopal Chetty, K.; Godbole, A.G.; Swarup, R.; Vaidya, V.N.; Venugopal, V.; Vasudeva Rao, P.R.

    2006-01-01

    The sorption of Pu from nitric acid solutions containing oxalate/fluoride was studied using an indigenously available macroporous bifunctional phosphinic acid (MPBPA) resin. Batch experiments were carried out to obtain the distribution data of Pu(IV) with a view to optimize conditions for its recovery from nitric acid waste solutions containing oxalate or fluoride ions. The measurements showed high distribution ratio (D) values even in the presence of strong complexing ions, like oxalate and fluoride, indicating the possibility of recovery of Pu from these types of waste solution. Column studies were carried out using this resin to recover Pu from the oxalate supernatant waste solution, which showed that up to 99% of Pu could be adsorbed on the resin. Elution of Pu loaded on the resin was studied using different eluting agents. (author)

  12. Template-assisted electrostatic spray deposition as a new route to mesoporous, macroporous, and hierarchically porous oxide films.

    Science.gov (United States)

    Sokolov, S; Paul, B; Ortel, E; Fischer, A; Kraehnert, R

    2011-03-01

    A novel film coating technique, template-assisted electrostatic spray deposition (TAESD), was developed for the synthesis of porous metal oxide films and tested on TiO(2). Organic templates are codeposited with the titania precursor by electrostatic spray deposition and then removed during calcination. Resultant films are highly porous with pores casted by uniformly sized templates, which introduced a new level of control over the pore morphology for the ESD method. Employing the amphiphilic block copolymer Pluronic P123, PMMA latex spheres, or a combination of the two, mesoporous, macroporous, and hierarchically porous TiO(2) films are obtained. Decoupled from other coating parameters, film thickness can be controlled by deposition time or depositing multiple layers while maintaining the coating's structure and integrity.

  13. Development of a novel starch with a three-dimensional ordered macroporous structure for improving the dissolution rate of felodipine

    Energy Technology Data Exchange (ETDEWEB)

    Hao, Yanna; Wu, Chao, E-mail: wuchao27@126.com; Zhao, Zongzhe; Zhao, Ying; Xu, Jie; Qiu, Yang; Jiang, Jie; Yu, Tong; Ma, Chunyu; Zhou, Buyun

    2016-01-01

    In this study, silica nanospheres with different particle sizes were used as hard template for synthesis of a starch with a novel three-dimensional ordered macroporous structure (3DOMTS). As a pharmaceutical adjuvant, 3DOMTS was used to improve the dissolution rate and oral relative bioavailability of water-insoluble drugs. Felodipine (FDP) was chosen as a model drug and was loaded into the 3DOMTS by solvent evaporation. FDP loading into 3DOMTS with different pore sizes was characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), differential scanning calorimeter (DSC), powder X-ray diffractometer (PXRD) and Fourier-Transform Infrared (FTIR). The results obtained showed that FDP was present in the pores in an amorphic or microcrystalline state. The in vitro dissolution results showed that 3DOMTS could effectively improve the dissolution rate of FDP in comparison with commercial common tablets. Pharmacokinetic results indicated that the oral relative bioavailability of self-made FDP–3DOMTS tablets were 184%, showing that 3DOMTS produced a significantly increased oral absorption of FDP. In conclusion, 3DOMTS exhibits the dual potential of improving the dissolution rate of poorly water soluble drugs and the novel filler produced by direct compression technology confirming that 3DOMTS will be useful for many applications in the field of pharmaceutics. - Highlights: • We successfully prepared a starch with a novel three-dimensional ordered macroporous structure (3DOMTS). • 3DOMTS can suppress the crystallinity of the drug to maintain it at amorphous state. • In vivo and in vitro experiments proved that 3DOMTS can improve the solubility and bioavailability of felodipine.

  14. 3D-macroporous chitosan-based scaffolds with in situ formed Pd and Pt nanoparticles for nitrophenol reduction.

    Science.gov (United States)

    Berillo, Dmitriy; Cundy, Andrew

    2018-07-15

    3D-macroporous chitosan-based scaffolds (cryogels) were produced via growth of metal-polymer coordinated complexes and electrostatic interactions between oppositely charged groups of chitosan and metal ions under subzero temperatures. A mechanism of reduction of noble metal complexes inside the cryogel walls by glutaraldehyde is proposed, which produces discrete and dispersed noble metal nanoparticles. 3D-macroporous scaffolds prepared under different conditions were characterised using TGA, FTIR, nitrogen adsorption, SEM, EDX and TEM, and the distribution of platinum nanoparticles (PtNPs) and palladium nanoparticles (PdNPs) in the material assessed. The catalytic activity of the in situ synthesised PdNPs, at 2.6, 12.5 and 21.0 μg total mass, respectively, was studied utilising a model system of 4-nitrophenol reduction. The kinetics of the reaction under different conditions (temperature, concentration of catalyst) were examined, and a decrease of catalytic activity was not observed over 17 treatment cycles. Increasing the temperature of the catalytic reaction from 10 to 22 and 35 °C by PdNPs supported within the cryogel increased the kinetic rate by 44 and 126%, respectively. Turnover number and turnover frequency of the PdNPs catalysts at room temperature were in the range 0.20-0.53 h -1 . The conversion degree of 4-nitrophenol at room temperature reached 98.9% (21.0 μg PdNPs). Significantly less mass of palladium nanoparticles (by 30-40 times) was needed compared to published data to obtain comparable rates of reduction of 4-nitrophenol. Copyright © 2018 Elsevier Ltd. All rights reserved.

  15. Poly(ethylene oxide) surfactant polymers

    OpenAIRE

    VACHEETHASANEE, KATANCHALEE; WANG, SHUWU; QIU, YONGXING; MARCHANT, ROGER E.

    2004-01-01

    We report on a series of structurally well-defined surfactant polymers that undergo surface-induced self-assembly on hydrophobic biomaterial surfaces. The surfactant polymers consist of a poly(vinyl amine) backbone with poly(ethylene oxide) and hexanal pendant groups. The poly(vinyl amine) (PVAm) was synthesized by hydrolysis of poly(N-vinyl formamide) following free radical polymerization of N-vinyl formamide. Hexanal and aldehyde-terminated poly (ethyleneoxide) (PEO) were simultaneously att...

  16. Ceramic Identity Contributes to Mechanical Properties and Osteoblast Behavior on Macroporous Composite Scaffolds

    Directory of Open Access Journals (Sweden)

    J. Kent Leach

    2012-05-01

    Full Text Available Implants formed of metals, bioceramics, or polymers may provide an alternative to autografts for treating large bone defects. However, limitations to each material motivate the examination of composites to capitalize on the beneficial aspects of individual components and to address the need for conferring bioactive behavior to the polymer matrix. We hypothesized that the inclusion of different bioceramics in a ceramic-polymer composite would alter the physical properties of the implant and the cellular osteogenic response. To test this, composite scaffolds formed from poly(lactide-co-glycolide (PLG and either hydroxyapatite (HA, β-tricalcium phosphate (TCP, or bioactive glass (Bioglass 45S®, BG were fabricated, and the physical properties of each scaffold were examined. We quantified cell proliferation by DNA content, osteogenic response of human osteoblasts (NHOsts to composite scaffolds by alkaline phosphatase (ALP activity, and changes in gene expression by qPCR. Compared to BG-PLG scaffolds, HA-PLG and TCP-PLG composite scaffolds possessed greater compressive moduli. NHOsts on BG-PLG substrates exhibited higher ALP activity than those on control, HA-, or TCP-PLG scaffolds after 21 days, and cells on composites exhibited a 3-fold increase in ALP activity between 7 and 21 days versus a minimal increase on control scaffolds. Compared to cells on PLG controls, RUNX2 expression in NHOsts on composite scaffolds was lower at both 7 and 21 days, while expression of genes encoding for bone matrix proteins (COL1A1 and SPARC was higher on BG-PLG scaffolds at both time points. These data demonstrate the importance of selecting a ceramic when fabricating composites applied for bone healing.

  17. Analysis of Flavonoids in Lotus (Nelumbo nucifera Leaves and Their Antioxidant Activity Using Macroporous Resin Chromatography Coupled with LC-MS/MS and Antioxidant Biochemical Assays

    Directory of Open Access Journals (Sweden)

    Ming-Zhi Zhu

    2015-06-01

    Full Text Available Lotus (Nelumbo nucifera leaves, a traditional Chinese medicinal herb, are rich in flavonoids. In an effort to thoroughly analyze their flavonoid components, macroporous resin chromatography coupled with HPLC-MS/MS was employed to simultaneously enrich and identify flavonoids from lotus leaves. Flavonoids extracted from lotus leaves were selectively enriched in the macroporous resin column, eluted subsequently as fraction II, and successively subjected to analysis with the HPLC-MS/MS and bioactivity assays. Altogether, fourteen flavonoids were identified, four of which were identified from lotus leaves for the first time, including quercetin 3-O-rhamnopyranosyl-(1→2-glucopyranoside, quercetin 3-O-arabinoside, diosmetin 7-O-hexose, and isorhamnetin 3-O-arabino- pyranosyl-(1→2-glucopyranoside. Further bioactivity assays revealed that these flavonoids from lotus leaves possess strong antioxidant activity, and demonstrate very good potential to be explored as food supplements or even pharmaceutical products to improve human health.

  18. Three-Dimensional Macroporous Polypyrrole-Derived Graphene Electrode Prepared by the Hydrogen Bubble Dynamic Template for Supercapacitors and Metal-Free Catalysts.

    Science.gov (United States)

    Yang, Xiaoqing; Liu, Anran; Zhao, Yuewu; Lu, Huijia; Zhang, Yuanjian; Wei, Wei; Li, Ying; Liu, Songqin

    2015-10-28

    We report a general method for the fabrication of three-dimensional (3D) macroporous graphene/conducting polymer modified electrode and nitrogen-doped graphene modified electrode. This method involves three consecutive steps. First, the 3D macroporous graphene (3D MG) electrode was fabricated electrochemically by reducing graphene oxide dispersion on different conducting substrates and used hydrogen bubbles as the dynamic template. The morphology and pore size of 3D MG could be governed by the use of surfactants and the dynamics of bubble generation and departure. Second, 3D macroporous graphene/polypyrrole (MGPPy) composites were constructed via directly electropolymerizing pyrrole monomer onto the networks of 3D MG. Due to the benefit of the good conductivity of 3D MG and pseudocapacitance of PPy, the composites manifest outstanding area specific capacitance of 196 mF cm(-2) at a current density of 1 mA cm(-2). The symmetric supercapacitor device assembled by the composite materials had a good capacity property. Finally, the nitrogen-doped MGPPy (N-MGPPy or MGPPy-X) with 3D macroporous nanostructure and well-regulated nitrogen doping was prepared via thermal treatment of the composites. The resultant N-MGPPy electrode was explored as a good electrocatalyst for the oxygen reduction reaction (ORR) with the current density value of 5.56 mA cm(-2) (-0.132 V vs Ag/AgCl). Moreover, the fuel tolerance and durability under the electrochemical environment of the N-MGPPy catalyst were found to be superior to the Pt/C catalyst.

  19. Synthesis of hierarchically meso-macroporous TiO2/CdS heterojunction photocatalysts with excellent visible-light photocatalytic activity.

    Science.gov (United States)

    Zhao, Haixin; Cui, Shu; Yang, Lan; Li, Guodong; Li, Nan; Li, Xiaotian

    2018-02-15

    Photocatalysts with a hierarchically porous structure have attracted considerable attention owing to their wide pore size distribution and high surface area, which enhance the efficiency of transporting species to active sites. In this study, hierarchically meso-macroporous TiO 2 photocatalysts decorated with highly dispersed CdS nanoparticles were synthesized via hydrolysis, followed by a hydrothermal treatment. The textural mesopores and interconnected pore framework provided more accessible active sites and efficient mass transport for the photocatalytic process. The light collection efficiency was enhanced because of multiple scattering of incident light in the macropores. Moreover, the formation of a heterojunction between the CdS and TiO 2 nanoparticles extended the photoresponse of TiO 2 to the visible-light range and enhanced the charge separation efficiency. Therefore, the hierarchically meso-macroporous TiO 2 /CdS photocatalysts exhibited excellent photocatalytic activity for the degradation of rhodaming B under visible-light irradiation. Trapping experiments demonstrated that superoxide radicals (O 2 - ) and hydroxyl radicals (OH) were the main active species in photocatalysis. A reasonable photocatalytic mechanism of TiO 2 /CdS heterojunction photocatalysts was also presented. Copyright © 2017 Elsevier Inc. All rights reserved.

  20. The growth of high density network of MOF nano-crystals across macroporous metal substrates - Solvothermal synthesis versus rapid thermal deposition

    Science.gov (United States)

    Maina, James W.; Gonzalo, Cristina Pozo; Merenda, Andrea; Kong, Lingxue; Schütz, Jürg A.; Dumée, Ludovic F.

    2018-01-01

    Fabrication of metal organic framework (MOF) films and membranes across macro-porous metal substrates is extremely challenging, due to the large pore sizes across the substrates, poor wettability, and the lack of sufficient reactive functional groups on the surface, which prevent high density nucleation of MOF crystals. Herein, macroporous stainless steel substrates (pore size 44 × 40 μm) are functionalized with amine functional groups, and the growth of ZIF-8 crystals investigated through both solvothermal synthesis and rapid thermal deposition (RTD), to assess the role of synthesis routes in the resultant membranes microstructure, and subsequently their performance. Although a high density of well interconnected MOF crystals was observed across the modified substrates following both techniques, RTD was found to be a much more efficient route, yielding high quality membranes under 1 h, as opposed to the 24 h required for solvothermal synthesis. The RTD membranes also exhibited high gas permeance, with He permeance of up to 2.954 ± 0.119 × 10-6 mol m-2 s-1 Pa-1, and Knudsen selectivities for He/N2, Ar/N2 and CO2/N2, suggesting the membranes were almost defect free. This work opens up route for efficient fabrication of MOF films and membranes across macro-porous metal supports, with potential application in electrically mediated separation applications.

  1. Enhanced Efficiency of Dye-Sensitized Solar Cells with Mesoporous-Macroporous TiO2 Photoanode Obtained Using ZnO Template

    Science.gov (United States)

    Pham, Trang T. T.; Mathews, Nripan; Lam, Yeng-Ming; Mhaisalkar, Subodh

    2017-06-01

    Improved light harvesting efficiency can be achieved by enhancing the optical properties of the titanium dioxide (TiO2) photoanode in dye-sensitized solar cells (DSSCs), leading to higher power conversion efficiency. By incorporating submicrometer cavities in TiO2 mesoporous film, using zinc oxide (ZnO) particles as a template, a bimodal pore size structure has been created, called a mesoporous-macroporous nanostructure. This photoanode structure consists of 20-nm TiO2 nanoparticles with two kinds of pores with size of 20 nm (mesopores) and 500 nm (macropores). Energy-dispersive x-ray spectroscopy and x-ray diffraction studies showed no trace of ZnO in the TiO2 after removal by TiCl4 treatment. Higher diffuse transmittance of this film compared with the standard transparent photoanode provides evidence of improved light scattering. When employed in a device, the incident-photon-to-current efficiency of ZnO-assisted devices showed enhancement at longer wavelengths, corresponding to the Mie light scattering effect with the macropores as scattering centers. This resulted in overall higher power conversion efficiency of the DSSC. In this work, a nonvolatile gel ionic liquid was used as the electrolyte to also demonstrate the benefit of this structure in combination with a viscous electrolyte and its promising application to prolong the stability of DSSCs.

  2. Fabrication and properties of meso-macroporous electrodes screen-printed from mesoporous titania nanoparticles for dye-sensitized solar cells

    International Nuclear Information System (INIS)

    Ma Liang; Liu Min; Peng Tianyou; Fan Ke; Lu Lanlan; Dai Ke

    2009-01-01

    A meso-macroporous TiO 2 film electrode was fabricated by using mesoporous TiO 2 (m-TiO 2 ) nanoparticles through a screen-printing technique in order to efficiently control the main fabrication step of dye-sensitized solar cells (DSSCs). The qualities of the screen-printed m-TiO 2 films were characterized by means of spectroscopy, electron microscopy, nitrogen adsorption-desorption and photoelectrochemical measurements. Under the optimal paste composition and printing conditions, the DSSC based on the meso-macroporous m-TiO 2 film electrode exhibits an energy conversion efficiency of 4.14%, which is improved by 1.70% in comparison with DSSC made with commercially available nonporous TiO 2 nanoparticles (P25, Degussa) electrode printed with a similar paste composition. The meso-macroporous structure within the m-TiO 2 film is of great benefit to the dye adsorption, light absorption and the electrolyte transportation, and then to the improvement of the overall energy conversion efficiency of DSSC.

  3. An Efficient Protocol for Preparation of Gallic Acid from Terminalia bellirica (Gaertn.) Roxb by Combination of Macroporous Resin and Preparative High-Performance Liquid Chromatography.

    Science.gov (United States)

    Zou, Denglang; Chen, Tao; Chen, Chen; Li, Hongmei; Liu, Yongling; Li, Yulin

    2016-08-01

    In this article, macroporous resin column chromatography and preparative high-performance liquid chromatography were applied for preparation of gallic acid from Terminalia bellirica (Gaertn.) Roxb. In the first step, six kinds of resins were investigated by adsorption and desorption tests and AB-8 macroporous resin was selected for the enrichment of gallic acid. As a result, 20 g of gallic acid at a purity of 71% could be separated from 100 g of crude extract in which the content of gallic acid was 16.7% and the recovery of gallic acid reached 85.0%. In the second step, preparative high-performance liquid chromatography was selected to purify gallic acid. As a result, 640 mg of gallic acid at a purity of 99.1% was obtained from 1 g of sample in 35 min. The results demonstrated that macroporous resin coupled with preparative high-performance liquid chromatography was suitable for preparation of gallic acid from T. bellirica (Gaertn.) Roxb. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  4. Acetylene Black Induced Heterogeneous Growth of Macroporous CoV2O6 Nanosheet for High-Rate Pseudocapacitive Lithium-Ion Battery Anode.

    Science.gov (United States)

    Zhang, Lei; Zhao, Kangning; Luo, Yanzhu; Dong, Yifan; Xu, Wangwang; Yan, Mengyu; Ren, Wenhao; Zhou, Liang; Qu, Longbing; Mai, Liqiang

    2016-03-23

    Metal vanadates suffer from fast capacity fading in lithium-ion batteries especially at a high rate. Pseudocapacitance, which is associated with surface or near-surface redox reactions, can provide fast charge/discharge capacity free from diffusion-controlled intercalation processes and is able to address the above issue. In this work, we report the synthesis of macroporous CoV2O6 nanosheets through a facile one-pot method via acetylene black induced heterogeneous growth. When applied as lithium-ion battery anode, the macroporous CoV2O6 nanosheets show typical features of pseudocapacitive behavior: (1) currents that are mostly linearly dependent on sweep rate and (2) redox peaks whose potentials do not shift significantly with sweep rate. The macroporous CoV2O6 nanosheets display a high reversible capacity of 702 mAh g(-1) at 200 mA g(-1), excellent cyclability with a capacity retention of 89% (against the second cycle) after 500 cycles at 500 mA g(-1), and high rate capability of 453 mAh g(-1) at 5000 mA g(-1). We believe that the introduction of pseudocapacitive properties in lithium battery is a promising direction for developing electrode materials with high-rate capability.

  5. Study of Ni Metallization in Macroporous Si Using Wet Chemistry for Radio Frequency Cross-Talk Isolation in Mixed Signal Integrated Circuits

    Directory of Open Access Journals (Sweden)

    King-Ning Tu

    2011-05-01

    Full Text Available A highly conductive moat or Faraday cage of through-the-wafer thickness in Si substrate was proposed to be effective in shielding electromagnetic interference thereby reducing radio frequency (RF cross-talk in high performance mixed signal integrated circuits. Such a structure was realized by metallization of selected ultra-high-aspect-ratio macroporous regions that were electrochemically etched in p− Si substrates. The metallization process was conducted by means of wet chemistry in an alkaline aqueous solution containing Ni2+ without reducing agent. It is found that at elevated temperature during immersion, Ni2+ was rapidly reduced and deposited into macroporous Si and a conformal metallization of the macropore sidewalls was obtained in a way that the entire porous Si framework was converted to Ni. A conductive moat was as a result incorporated into p− Si substrate. The experimentally measured reduction of crosstalk in this structure is 5~18 dB at frequencies up to 35 GHz.

  6. Tacticities study of high poly-α-olefins, from poly-1-hexene to poly-1-octadecene, obtained with metallocenes catalysts

    International Nuclear Information System (INIS)

    Silva, Luciano F. da; Galland, Griselda B.

    2003-01-01

    High poly-α-olefins such as poly-1-hexene, poly-1-octene, poly-1-decene, poly-1-dodecene, poly-1-tetradecene, poly-1-hexadecene and poly-1-octadecene were obtained with the homogeneous iso specific catalyst rac-Et[Ind]ZrCl 2 /MAO and with the homogeneous syndiospecific catalyst Me 2 C[Cp(9-Flu)]ZrCl 2 /MAO at the polymerization temperatures of 0 deg C, 30 deg C and 60 deg C. The polymers were analyzed by 13 C NMR to study the influence of the α - olefins sizes, the catalysts type and the polymerization temperatures in their tacticities. The stereospecific control of both catalytic systems decreased with the increase of the reaction temperature and with the α-olefin size. (author)

  7. Enrichment of antioxidants in black garlic juice using macroporous resins and their protective effects on oxidation-damaged human erythrocytes.

    Science.gov (United States)

    Zou, Ying; Zhao, Mouming; Yang, Kun; Lin, Lianzhu; Wang, Yong

    2017-08-15

    The black garlic juice is popular for its nutritive value. Enrichment of antioxidants is needed to make black garlic extract an effective functional ingredient. Five macroporous resins were evaluated for their capacity in adsorbing antioxidants in black garlic juice. XAD-16 resin was chosen for further study due to its high adsorption and desorption ratios. Pseudo-second-order kinetics (q e =625μmol Trolox equiv/g dry resin, k 2 =0.0001463) and Freundlich isotherm models (ΔH=-10.1547kJ/mol) were suitable for describing the whole exothermic and physical adsorption processes of the antioxidants from black garlic juice on XAD-16 resin. The antioxidants and phenolics were mostly enriched in 40% ethanol fraction by XAD-16 resin column chromatography. The black garlic extract and its fractions could protect erythrocytes against AAPH-induced hemolysis in dose-dependent manners. The pretreatment of AAPH-damaged erythrocytes with 40% ethanol fractions (2.5mg/mL) significantly decreased the hemolysis ratios from 53.58% to 3.79%. The 40% ethanol fraction possessing strong intracellular antioxidant activity could be used as a functional food ingredient. Copyright © 2017 Elsevier B.V. All rights reserved.

  8. Formation mechanism of 3D macroporous graphene aerogel in alcohol-water media under gamma-ray radiation

    Science.gov (United States)

    Wang, Weikang; Wu, Yihu; Jiang, Zhiwen; Wang, Mozhen; Wu, Qichao; Zhou, Xiao; Ge, Xuewu

    2018-01-01

    The subtle control on the self-assembly behavior of graphene oxide (GO) nanosheets is one of effective ways for the preparation of high-performance macroscopic graphene-based materials. In this work, detailed characterizations and discussion on the morphological and compositional changes on the solid products in various alcohol-water dispersions of GO under γ-ray radiation were carried out, proving the concurrent hydroxyalkylation and reduction processes of GO nanosheets in the system, which triggered the spontaneous self-assembly of the hydroxyalkylated and reduced GO nanosheets (HA-rGO). The pH and the volume ratio of alcohol to water (ϕa/w) are the key factors to control the self-assembly of the HA-rGO sheets. A free-standing graphene hydrogel (GH) only forms in the strong acid alcohol-water media with an appropriate ϕa/w. After the freeze-drying of the GH, a macroporous graphene aerogel (GA) was obtained, which exhibited a high absorption performance for not only nonpolar molecules (cyclohexane and kerosene), but also most polar molecules (toluene, chloroform, glycol, etc). This work demonstrates a comprehensive self-assembly mechanism of GO nanosheets in an aqueous media under γ-ray radiation and reveals that GA produced from the reduction of GO can be used as potential super-adsorbents for not only waste oil, but also the polar alcohols.

  9. Synthesis and application of nano-, meso- and macroporous sorbents based on lignin for detoxication of biological fluids

    Science.gov (United States)

    Chopabayeva, Nazira N.; Mukanov, Kanatbek N.; Tasmagambet, Amandyk T.

    2014-05-01

    Novel nano-, meso- and macroporous sorbents based on hydrolysis lignin have been synthesized by catalytic o-alkylation of biolpolymer with epoxy resin ED-20 and subsequent amination of formed α-oxyde derivative. Composition, structure, morphology and physical, chemical properties of ion-exchangers were investigated by FTIR, SEM, TEM, porosimetry and potentiometric titration method. It has been established that alkaline activated lignin shows an increase of SBET to 20.9 m2/g while modification leads to decrease of SBET more than double (from 9.2 to 5.2 m2/g) that of an untreared sample (14.5 m2/g). Synthesized sorbents are characterized by approximately identical mesoporous structure and mainly contained a pore size of 10-14 nm. The results clearly demonstrate the efficiency of lignin based sorbents for the removal of water and lipid soluble toxic metabolites from blood serum of diabetic retinopathy patients. Samples reduced the high level of total cholesterol, including its most atherogenic fractions (LDL-C, VLDL-C), triglyceride to the level of optimum compensated diabetes without significant removal of HDL-C. Concentration of glucose was decreased to physiological norms.

  10. Ice as a Green-Structure-Directing Agent in the Synthesis of Macroporous MWCNTs and Chondroitin Sulphate Composites

    Science.gov (United States)

    Nardecchia, Stefania; Serrano, María Concepción; García-Argüelles, Sara; Maia Da Costa, Marcelo E. H.; Ferrer, María Luisa; Gutiérrez, María C.

    2017-01-01

    The incorporation of multi-walled carbon nanotubes (MWCNTs) into chondroitin sulphate-based scaffolds and the effect on the structural, mechanical, conductive, and thermal properties of the resulting scaffolds is investigated. Three-dimensional hierarchical materials are prepared upon the application of the ice segregation-induced self-assembly (ISISA) process. The use of ice as structure-directing agents avoids chemicals typically used for this purpose (e.g., surfactants, block copolymers, etc.), hence, emphasising the green features of this soft-templating approach. We determine the critical parameters that control the morphology of the scaffolds formed upon ice-templating (i.e., MWCNTs type, freezing conditions, polymer and MWCNT concentration). MWCNTs are surface functionalized by acidic treatment. MWCNT functionalization is characterized by Raman, Fourier transfer infrared (FTIR) and X-ray Photoelectron (XPS) spectroscopies. Scanning electron microscopy (SEM) analysis and porosity studies reveal that MWCNT content modifies the morphology of the macroporous structure, which decreases by increasing MWCNT concentration. Differences in scaffold morphology should be translated into their conductivity and mechanical properties. As a general trend, the Young’s modulus and the electrical conductivity of the scaffolds increase with the MWCNT content. Preliminary biocompatibility tests with human osteoblast-like cells also reveal the capability of these structures to support cell growth. PMID:28772715

  11. Three-dimensional ordered macroporous MnO2/carbon nanocomposites as high-performance electrodes for asymmetric supercapacitors.

    Science.gov (United States)

    Yang, Chunzhen; Zhou, Ming; Xu, Qian

    2013-12-07

    MnO2/carbon composites with ultrathin MnO2 nanofibers (diameter of 5-10 nm) uniformly deposited on three dimensional ordered macroporous (3DOM) carbon frameworks were fabricated via a self-limiting redox process. The MnO2 nanofibers provide a large surface area for charge storage, whereas the 3DOM carbon serves as a desirable supporting material providing rapid ion and electron transport through the composite electrodes. Cyclic voltammetry, galvanostatic charge-discharge and electrochemical impedance spectroscopy (EIS) were used to characterize the capacitive performance of these composites. Optimization of the composition results in a composite with 57 wt% MnO2 content, which gives both a high specific capacitance (234 F g(-1) at a discharge current of 0.1 A g(-1)) and good rate capability (52% retention of the capacitance at 5 A g(-1)). An asymmetric supercapacitor was fabricated by assembling the optimized MnO2/carbon composite as the positive electrode and 3DOM carbon as the negative electrode. The asymmetric supercapacitor exhibits superior electrochemical performances, which can be reversibly charged and discharged at a maximum cell voltage of 2.0 V in 1.0 M Na2SO4 aqueous electrolyte, delivering both high energy density (30.2 W h kg(-1)) and power density (14.5 kW kg(-1)). Additionally, the asymmetric supercapacitor exhibits an excellent cycle life, with 95% capacitance retained after 1000 cycles.

  12. Formation of carbon nanosheets via simultaneous activation and catalytic carbonization of macroporous anion-exchange resin for supercapacitors application.

    Science.gov (United States)

    Peng, Hui; Ma, Guofu; Sun, Kanjun; Mu, Jingjing; Zhang, Zhe; Lei, Ziqiang

    2014-12-10

    Two-dimensional mesoporous carbon nanosheets (CNSs) have been prepared via simultaneous activation and catalytic carbonization route using macroporous anion-exchange resin (AER) as carbon precursor and ZnCl2 and FeCl3 as activating agent and catalyst, respectively. The iron catalyst in the skeleton of the AER may lead to carburization to form a sheetlike structure during the carbonization process. The obtained CNSs have a large number of mesopores, a maximum specific surface area of 1764.9 m(2) g(-1), and large pore volume of 1.38 cm(3) g(-1). As an electrode material for supercapacitors application, the CNSs electrode possesses a large specific capacitance of 283 F g(-1) at 0.5 A g(-1) and excellent rate capability (64% retention ratio even at 50 A g(-1)) in 6 mol L(-1) KOH. Furthermore, CNSs symmetric supercapacitor exhibits specific energies of 17.2 W h kg(-1) at a power density of 224 W kg(-1) operated in the voltage range of 0-1.8 V in 0.5 mol L(-1) Na2SO4 aqueous electrolyte, and outstanding cyclability (retains about 96% initial capacitance after 5000 cycles).

  13. High-rate capability of three-dimensionally ordered macroporous T-Nb2O5 through Li+ intercalation pseudocapacitance

    Science.gov (United States)

    Lou, Shuaifeng; Cheng, Xinqun; Wang, Long; Gao, Jinlong; Li, Qin; Ma, Yulin; Gao, Yunzhi; Zuo, Pengjian; Du, Chunyu; Yin, Geping

    2017-09-01

    Orthorhombic Niobium oxide (T-Nb2O5) has been regarded as a promising anode material for high-rate lithium ion batteries (LIBs) due to its potential to operate at high rates with improved safety and high theoretical capacity of 200 mA h g-1. Herein, three-dimensionally ordered macroporous (3DOM) T-Nb2O5, with mesoporous hierarchical structure, was firstly prepared by a simple approach employing self-assembly polystyrene (PS) microspheres as hard templates. The obtained T-Nb2O5 anode material presents obvious and highly-efficiency pseudocapacitive Li+ intercalation behaviour, which plays a dominant role in the kinetics of electrode process. As a result, rapid Li+ intercalation/de-intercalation are achieved, leading to excellent rate capability and long cycle life. The 3DOM T-Nb2O5 shows a remarkable high capacity of 106 and 77 mA h g-1 at the rate of 20C and 50C. The work presented herein holds great promise for future design of material structure, and demonstrates the great potential of T-Nb2O5 as a practical high-rate anode material for LIBs.

  14. Label-free electrochemical immunoassay for neuron specific enolase based on 3D macroporous reduced graphene oxide/polyaniline film.

    Science.gov (United States)

    Zhang, Qi; Li, Xiaoyan; Qian, Chunhua; Dou, Li; Cui, Feng; Chen, Xiaojun

    2018-01-01

    The content of neuron specific enolase (NSE) in serum is considered to be an essential indicator of small cell lung cancer (SCLC). Here, a novel label-free electrochemical immunoassay for the detection of NSE based on the three dimensionally macroporous reduced graphene oxide/polyaniline (3DM rGO/PANI) film has been proposed. The 3DM rGO/PANI film was constructed by electrochemical co-deposition of GO and aniline into the interspaces of a sacrificial silica opal template modified Au slice. During the co-deposition, GO was successfully reduced by aniline and PANI could be deposited on the surfaces of rGO sheets. The ratio of rGO and PANI in the composite was also optimized to achieve the maximum electrochemical performance. The 3DM rGO/PANI composite provided larger specific surface area for the antibody immobilization, exhibited enhanced conductivity for electron transfer, and more important was that PANI acted as the electroactive probe for indicating the NSE concentration. Under the optimal conditions, a linear current response of PANI to NSE concentration was obtained over 0.5 pg mL -1 -10.0 ng mL -1 with a detection limit of 0.1 pg mL -1 . Moreover, the immunosensor showed excellent selectivity, good stability, satisfactory reproducibility and regeneration, and was employed to detect NSE in clinical serum specimens. Copyright © 2017 Elsevier Inc. All rights reserved.

  15. Formation of different micro-morphologies from VO2 and ZnO crystallization using macro-porous silicon substrates

    Science.gov (United States)

    Salazar-Kuri, U.; Antúnez, E. E.; Estevez, J. O.; Olive-Méndez, Sion F.; Silva-González, N. R.; Agarwal, V.

    2017-05-01

    Square-shaped macropores produced by electrochemical anodization of n- and p-type Si wafers have been used as centers of nucleation to crystallize VO2 and ZnO. Substrate roughness dependent formation of different morphologies is revealed in the form of squared particles, spheres, bars and ribbons in the case of VO2 and hexagonal piles and spheres in the case of ZnO, have been observed.The presence of nano-/micro-metric crystals was studied through field emission scanning electron microscopy and energy dispersive X-ray spectroscopy mapping. Crystal structure of metal oxides was confirmed by micro-Raman spectroscopy. The growth of the different morphologies has been explained in terms of the surface free energy of a bare Si/SiO2 substrate and its modification originated from the roughness of the surface and of the walls of the porous substrates. This energy plays a crucial role on the minimization of the required energy to induce heterogeneous nucleation and crystal growth. Present work strengthens and provides an experimental evidence of roughness dependent metal oxide crystal growth with well-defined habits from pore corners and rough sides of the pore walls, similar to already reported protein crystals.

  16. Template-free synthesis of renewable macroporous carbon via yeast cells for high-performance supercapacitor electrode materials.

    Science.gov (United States)

    Sun, Hongmei; He, Wenhui; Zong, Chenghua; Lu, Lehui

    2013-03-01

    The urgent need for sustainable development has forced material scientists to explore novel materials for next-generation energy storage devices through a green and facile strategy. In this context, yeast, which is a large group of single cell fungi widely distributed in nature environments, will be an ideal candidate for developing effective electrode materials with fascinating structures for high-performance supercapacitors. With this in mind, herein, we present the first example of creating three-dimensional (3D) interpenetrating macroporous carbon materials via a template-free method, using the green, renewable, and widespread yeast cells as the precursors. Remarkably, when the as-prepared materials are used as the electrode materials for supercapacitors, they exhibit outstanding performance with high specific capacitance of 330 F g(-1) at a current density of 1 A g(-1), and good stability, even after 1000 charge/discharge cycles. The approach developed in this work provides a new view of making full use of sustainable resources endowed by nature, opening the avenue to designing and producing robust materials with great promising applications in high-performance energy-storage devices.

  17. The efficiency of macroporous polystyrene ion-exchange resins in natural organic matter removal from surface water

    Directory of Open Access Journals (Sweden)

    Urbanowska Agnieszka

    2017-01-01

    Full Text Available Natural water sources used for water treatment contains various organic and inorganic compounds. Surface waters are commonly contaminated with natural organic matter (NOM. NOM removal from water is important e.g. due to lowering the risk of disinfection by-product formation during chlorination. Ion exchange with the use of synthetic ion-exchange resins is an alternative process to typical NOM removal approach (e.g. coagulation, adsorption or oxidation as most NOM compounds have anionic character. Moreover, neutral fraction could be removed from water due to its adsorption on resin surface. In this study, applicability of two macroporous, polystyrene ion exchange resins (BD400FD and A100 in NOM removal from water was assessed including comparison of treatment efficiency in various process set-ups and conditions. Moreover, resin regeneration effectivity was determined. Obtained results shown that examined resins could be applied in NOM removal and it should be noticed that column set-up yielded better results (contrary to batch set-up. Among the examined resins A100 one possessed better properties. It was determined that increase of solution pH resulted in a slight decrease in treatment efficiency while higher temperature improved it. It was also observed that regeneration efficiency was comparable in both tested methods but batch set-up required less reagents.

  18. Development of the preparation technology of macroporous sorbent for industrial off-gas treatment including 14C

    International Nuclear Information System (INIS)

    Cho, Il Hoon; Cho, Young Hyun; Park, Guen Il; Kim, In Tae; Kim, June Hyung; Ahn, Byung Kil

    2001-01-01

    For environmental and health effects due to increasing levels of pollution in the atmosphere, it is necessary to develop environmentally sound technologies for the treatment of greenhouse gases (CO 2 , CH 4 , CFC, etc.) and acid gases (SOx, NOx, etc.). Specifically, advanced technology for CO 2 capturing is currently one of the most important environmental issues in worldwide. 14 CO 2 , specially which has been gradually emerging issue in the nuclear facilities, is generated about 330 ppm from the CANDU (Canadian Deuterium Uranium Reactor) nuclear power plant and the DUPIC (Direct Use of spent PWR fuel in CANDU reactors) process which is the process of spent fuel treatment. For this purpose, it is necessary to develop the most efficient treatment technology of CO 2 capture by various lime materials in semi- or dry process, it should be also considering a removal performance, waste recycling and safety of disposal. In order to develop a highly active slaked lime as a sorbent for CO 2 and high temperature desulfurization, macroporous slaked lime is necessarily prepared by modified swelling process and equipment, which was developed under carrying out this project. And also for the optimal removal process of off-gases the removal performance tests of various sorbents and the effects of relative humidity and bed depth on the removal capacity must be considered

  19. Development of the preparation technology of macroporous sorbent for industrial off-gas treatment including {sup 14}C

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Il Hoon; Cho, Young Hyun; Park, Guen Il; Kim, In Tae; Kim, June Hyung; Ahn, Byung Kil

    2001-01-01

    For environmental and health effects due to increasing levels of pollution in the atmosphere, it is necessary to develop environmentally sound technologies for the treatment of greenhouse gases (CO{sub 2}, CH{sub 4}, CFC, etc.) and acid gases (SOx, NOx, etc.). Specifically, advanced technology for CO{sub 2} capturing is currently one of the most important environmental issues in worldwide. {sup 14}CO{sub 2}, specially which has been gradually emerging issue in the nuclear facilities, is generated about 330 ppm from the CANDU (Canadian Deuterium Uranium Reactor) nuclear power plant and the DUPIC (Direct Use of spent PWR fuel in CANDU reactors) process which is the process of spent fuel treatment. For this purpose, it is necessary to develop the most efficient treatment technology of CO{sub 2} capture by various lime materials in semi- or dry process, it should be also considering a removal performance, waste recycling and safety of disposal. In order to develop a highly active slaked lime as a sorbent for CO{sub 2} and high temperature desulfurization, macroporous slaked lime is necessarily prepared by modified swelling process and equipment, which was developed under carrying out this project. And also for the optimal removal process of off-gases the removal performance tests of various sorbents and the effects of relative humidity and bed depth on the removal capacity must be considered.

  20. Macroporous graphitic carbon foam decorated with polydopamine as a high-performance anode for microbial fuel cell

    Science.gov (United States)

    Jiang, Hongmei; Yang, Lu; Deng, Wenfang; Tan, Yueming; Xie, Qingji

    2017-09-01

    Herein, a macroporous graphitic carbon foam (MGCF) electrode decorated with polydopamine (PDA) is used as a high-performance anode for microbial fuel cell (MFC) applications. The MGCF is facilely prepared by pyrolysis of a powder mixture comprising maltose, nickel nitrate, and ammonia chloride, without using solid porous template. The MGCF is coated with PDA by self-polymerization of dopamine in a basic solution. The MGCF can provide a large surface area for bacterial attachment, and PDA coated on the MGCF electrode can further promote bacterial adhesion resulting from the improved hydrophility, so the MGCF-PDA electrode as an anode in a MFC can show ultrahigh bacterial loading capacity. Moreover, the electrochemical oxidation of flavins at the MGCF-PDA electrode is greatly accelerated, so the extracellular electron transfer mediated by flavins is improved. As a result, the MFC equipped with a MGCF-PDA anode can show a maximum power density of 1735 mW cm-2, which is 6.7 times that of a MFC equipped with a commercial carbon felt anode, indicating a promising anode for MFC applications.

  1. Cell expansion of human articular chondrocytes on macroporous gelatine scaffolds-impact of microcarrier selection on cell proliferation

    Energy Technology Data Exchange (ETDEWEB)

    Pettersson, Sofia; Kratz, Gunnar [Laboratory for Reconstructive Plastic Surgery, Department of Clinical and Experimental Medicine, Linkoeping University, SE-581 85 Linkoeping (Sweden); Wetteroe, Jonas [Rheumatology/AIR, Department of Clinical and Experimental Medicine, Linkoeping University, SE-581 85 Linkoeping (Sweden); Tengvall, Pentti, E-mail: sofia.pettersson@liu.se [Institute of Clinical Sciences, Department of Biomaterials, The Sahlgrenska Academy at University of Gothenburg, SE-405 30 Gothenburg (Sweden)

    2011-12-15

    This study investigates human chondrocyte expansion on four macroporous gelatine microcarriers (CultiSpher) differing with respect to two manufacturing processes-the amount of emulsifier used during initial preparation and the gelatine cross-linking medium. Monolayer-expanded articular chondrocytes from three donors were seeded onto the microcarriers and cultured in spinner flask systems for a total of 15 days. Samples were extracted every other day to monitor cell viability and establish cell counts, which were analysed using analysis of variance and piecewise linear regression. Chondrocyte densities increased according to a linear pattern for all microcarriers, indicating an ongoing, though limited, cell proliferation. A strong chondrocyte donor effect was seen during the initial expansion phase. The final cell yield differed significantly between the microcarriers and our results indicate that manufacturing differences affected chondrocyte densities at this point. Remaining cells stained positive for chondrogenic markers SOX-9 and S-100 but extracellular matrix formation was modest to undetectable. In conclusion, the four gelatine microcarriers supported chondrocyte adhesion and proliferation over a two week period. The best yield was observed for microcarriers produced with low emulsifier content and cross-linked in water and acetone. These results add to the identification of optimal biomaterial parameters for specific cellular processes and populations.

  2. Poly(bisphenol A carbonate) - poly(dimethylsiloxane) multiblock copolymers

    NARCIS (Netherlands)

    Aert, van H.A.M.; Nelissen, L.N.I.H.; Lemstra, P.J.; Brunelle, D.J.

    2001-01-01

    A versatile technique for the synthesis of multiblock copolymers of polydimethylsiloxane (PDMS) and poly(bisphenol A carbonate) (PC) is described. Specific reaction of the phenol end groups of a,¿-bis(bisphenol A)-terminated PDMS with the activated end groups of

  3. Biodegradable poly(lactic acid)

    Indian Academy of Sciences (India)

    The fabrication of biodegradable poly(lactic acid) (PLA) microspheres containing total alkaloids of Caulis sinomenii was investigated. The formation, diameter, morphology and properties of the microspheres were characterized using Fourier transform infrared spectroscopy (FT–IR), laser particle size analyser and scanning ...

  4. Fabrication and biocompatibility of poly(L-lactic acid) and chitosan composite scaffolds with hierarchical microstructures

    Energy Technology Data Exchange (ETDEWEB)

    Lou, Tao, E-mail: taolou72@aliyun.com [College of Chemistry and Chemical Engineering, Qingdao University, Qingdao 266071 (China); Wang, Xuejun [College of Chemistry and Chemical Engineering, Qingdao University, Qingdao 266071 (China); Yan, Xu [College of Physics & Collaborative Innovation Center for Low-Dimensional Nanomaterials and Optoelectronic Devices, Qingdao University, Qingdao 266071 (China); Miao, Yu [Department of Mechanical Engineering, Columbia University, New York, NY 10027 (United States); Long, Yun-Ze, E-mail: yunzelong@163.com [College of Physics & Collaborative Innovation Center for Low-Dimensional Nanomaterials and Optoelectronic Devices, Qingdao University, Qingdao 266071 (China); Yin, Hai-Lei [Department of Osteology, No. 401 Hospital of P. L. A., Qingdao 266071 (China); Sun, Bin [College of Physics & Collaborative Innovation Center for Low-Dimensional Nanomaterials and Optoelectronic Devices, Qingdao University, Qingdao 266071 (China); Song, Guojun [College of Chemistry and Chemical Engineering, Qingdao University, Qingdao 266071 (China)

    2016-07-01

    The scaffold microstructure is crucial to reconstruct tissue normal functions. In this article, poly(L-lactic acid) and chitosan fiber (PLLA/CTSF) composite scaffolds with hierarchical microstructures both in fiber and pore sizes were successfully fabricated by combining thermal induced phase separation and salt leaching techniques. The composite scaffolds consisted of a nanofibrous PLLA matrix with diameter of 50–500 nm, and chitosan fibers with diameter of about 20 μm were homogenously distributed in the PLLA matrix as a microsized reinforcer. The composite scaffolds also had high porosity (> 94%) and hierarchical pore size, which were consisted of both micropores (50 nm–10 μm) and macropores (50–300 μm). By tailoring the microstructure and chemical composition, the mechanical property, pH buffer and protein adsorption capacity of the composite scaffold were improved significantly compared with those of PLLA scaffold. Cell culture results also revealed that the PLLA/CTSF composite scaffolds supported MG-63 osteoblast proliferation and penetration. - Highlights: • Composite scaffolds fabricated by combining thermal induced phase separation and salt leaching techniques • Hierarchical microstructure both in fiber and pore sizes • The scaffold microenvironment facilitates the protein adsorption, cell proliferation and penetration.

  5. Preparation of three-dimensionally ordered macroporous polycysteine film and application in sensitive detection of 4-chlorophenol

    International Nuclear Information System (INIS)

    Zhang, Shenghui; Shi, Zhen; Wang, Jinshou; Cheng, Qin; Wu, Kangbing

    2014-01-01

    Highlights: • Polycysteine film with three-dimensionally ordered porous structures was prepared. • 3-DOM polycysteine film exhibited large active area and signal enhancement effects. • 3-DOM polycysteine film increased oxidation signal of 4-chlorophenol by 5-fold. - Abstract: Polystyrene microspheres with diameter of 350 nm were prepared, and then used to arrange on the surface of glassy carbon electrode (GCE) as structure-directing template. By successive cyclic sweeps between −1.0 V and 2.0 V in pH 7 phosphate buffer containing 10 mM cysteine, polycysteine film was electrodeposited on polystyrene microspheres-arranged GCE. After removing polystyrene template, a three-dimensionally ordered macroporous (3-DOM) polycysteine film was achieved, as confirmed by scanning electron microscopy measurements. Electrochemical responses of K 3 [Fe(CN) 6 ] probe indicated that 3-DOM polycysteine film-modified GCE exhibited larger active area, compared with GCE, polycysteine film-modified GCE and electrochemically oxidized GCE. The application of 3-DOM polycysteine film in electrochemical detection of 4-chlorophenol was studied. Due to ordered porous structures, the 3-DOM polycysteine film-modified GCE displayed signal enhancement effects, and enhanced the oxidation peak currents of 4-chlorophenol. As a result, a sensitive electrochemical method was developed for the detection of 4-chlorophenol, and the detection limit was 1.67 × 10 −8 M. This new method was used to detect 4-chlorophenol in water samples, and the value of recovery was over the range from 99.6% to 107%

  6. Novel three-dimensionally ordered macroporous Fe{sup 3+}-doped TiO{sub 2} photocatalysts for H{sub 2} production and degradation applications

    Energy Technology Data Exchange (ETDEWEB)

    Yan, Xiaoqing; Xue, Chao; Yang, Bolun; Yang, Guidong, E-mail: guidongyang@xjtu.edu.cn

    2017-02-01

    Highlights: • 3DOM Fe{sup 3+}-doped TiO{sub 2} photocatalyst was prepared. • 3DOM structure showed high activity for decomposition of the RhB and the generation of H{sub 2}. • 3DOM structure provided interfacial reaction sites and optical absorption active sites. • The energy level from Fe{sup 3+} centers were existed in the band gap of TiO{sub 2}. • 3DOM structure promoted the separation of charge carriers. - Abstract: Novel three-dimensionally ordered macroporous (3DOM) Fe{sup 3+}-doped TiO{sub 2} photocatalysts were prepared using a colloidal crystal template method with low-cost raw material including ferric trichloride, isopropanol, tetrabutyl titanate and polymethyl methacrylate. The as-prepared 3DOM Fe{sup 3+}-doped TiO{sub 2} photocatalysts were characterized by various analytical techniques. TEM and SEM results showed that the obtained photocatalysts possess well-ordered macroporous structure in three dimensional orientations. As proved by XPS and EDX analysis that Fe{sup 3+} ions have been introduced TiO{sub 2} lattice and the doped Fe{sup 3+} ions can act as the electron acceptor/donor centers to significantly enhance the electron transfer from the bulk to surface of TiO{sub 2}, resulting in more electrons could take part in the oxygen reduction process thereby decreasing the recombination rate of photogenerated charges. Meanwhile, the 3DOM architecture with the feature of interfacial chemical reaction active sites and optical absorption active sites is remarkably favorable for the reactant transfer and light trapping in the photoreaction process. As a result, the 3DOM Fe{sup 3+}-doped TiO{sub 2} photocatalysts show the considerably higher photocatalytic activity for decomposition of the Rhodamine B (RhB) and the generation of hydrogen under visible light irradiation due to the synergistic effects of open, interconnected macroporous network and metal ion doping.

  7. 3D structure of macropore networks within natural and de-embarked estuary saltmarsh sediments: towards an improved understanding of network structural control over hydrologic function

    Science.gov (United States)

    Carr, Simon; Spencer, Kate; James, Tempest; Lucy, Diggens

    2015-04-01

    Saltmarshes are globally important environments which, though occupying biodiversity e.g. the EU Habitats Directive and Birds Directive. However, there is growing evidence that restored saltmarshes, recreated through the return to tidal inundation of previously drained and defended low-lying coastal land, do not have the same species composition even after 100 years and while environmental enhancement has been achieved, there may be consequences for ecosystem functioning This study presents the findings of a comparative analysis of detailed sediment structure and hydrological functioning of equivalent natural and de-embanked saltmarsh sediments at Orplands Farm, Essex, UK. 3D x-ray CT scanning of triplicate undisturbed sediment cores recovered in 2013 have been used to derive detailed volumetric reconstructions of macropore structure and networks, and to infer differences in bulk microporosity between natural and de-embanked saltmarshes. These volumes have been further visualised for qualitative analysis of the main sediment components, and extraction of key macropore space parameters for quantified analysis including total porosity and connectivity, as well as structure, organisation and efficiency (tortuosity) of macropore networks. Although total porosity was significantly greater within the de-embanked saltmarsh sediments, pore networks in these samples were less organised and more tortuous, and were also inferred to have significantly lower micro-porosity than those of the natural saltmarsh. These datasets are applied to explain significant differences in the hydraulic behaviour and functioning observed between natural and de-embarked saltmarsh at Orplands. Piezometer wells and pressure transducers recorded fluctuations in water level at 15 minute intervals over a 4.5 month period (winter 2011-2012). Basic patterns for water level fluctuations in both the natural and de-embanked saltmarsh are similar and reflect tidal flooding. However, in the de

  8. Ordered nanoporous silica as carriers for improved delivery of water insoluble drugs: a comparative study between three dimensional and two dimensional macroporous silica

    Directory of Open Access Journals (Sweden)

    Wang Y

    2013-10-01

    Full Text Available Ying Wang, Qinfu Zhao, Yanchen Hu, Lizhang Sun, Ling Bai, Tongying Jiang, Siling WangDepartment of Pharmaceutics, Shenyang Pharmaceutical University, Liaoning Province, People’s Republic of ChinaAbstract: The goal of the present study was to compare the drug release properties and stability of the nanoporous silica with different pore architectures as a matrix for improved delivery of poorly soluble drugs. For this purpose, three dimensional ordered macroporous (3DOM silica with 3D continuous and interconnected macropores of different sizes (200 nm and 500 nm and classic mesoporous silica (ie, Mobil Composition of Matter [MCM]-41 and Santa Barbara Amorphous [SBA]-15 with well-ordered two dimensional (2D cylindrical mesopores were successfully fabricated and then loaded with the model drug indomethacin (IMC via the solvent deposition method. Scanning electron microscopy (SEM, N2 adsorption, differential scanning calorimetry (DSC, and X-ray diffraction (XRD were applied to systematically characterize all IMC-loaded nanoporous silica formulations, evidencing the successful inclusion of IMC into nanopores, the reduced crystallinity, and finally accelerated dissolution of IMC. It was worth mentioning that, in comparison to 2D mesoporous silica, 3DOM silica displayed a more rapid release profile, which may be ascribed to the 3D interconnected pore networks and the highly accessible surface areas. The results obtained from the stability test indicated that the amorphous state of IMC entrapped in the 2D mesoporous silica (SBA-15 and MCM-41 has a better physical stability than in that of 3DOM silica. Moreover, the dissolution rate and stability of IMC loaded in 3DOM silica was closely related to the pore size of macroporous silica. The colorimetric 3-(4,5-Dimethylthiazol-2-yl-2,5-diphenyltetrazolium bromide (MTT and Cell Counting Kit (CCK-8 assays in combination with direct morphology observations demonstrated the good biocompatibility of nanoporous

  9. Study of the synthesis of TiO2 layers on macroporous ceramic supports in supercritical (SC) CO2 for processing radioactive aqueous effluents in dynamic mode

    International Nuclear Information System (INIS)

    Duchateau, Maxime

    2014-01-01

    Public and military nuclear industry generates a significant amount of radioactive liquid waste which must be treated before being released into the environment. Decontamination methods alternative to the industrial techniques (evaporation, chemical treatment) are being developed, such as column treatments or coupled filtration/sorption processes. Current researches mainly focus on the development and shaping of specific sorbents. In this context, the objectives of this thesis were first to study the synthesis of TiO 2 layers on macroporous ceramic supports in supercritical (SC) CO 2 and then to evaluate their potential for radionuclide extraction in these alternative processes. A robust synthesis method has been developed, based on the thermal decomposition of titanium isopropoxide in SC CO 2 in the temperature range between 150 C and 350 C. Nano-structured TiO 2 films were formed on the macroporous supports (ceramic foams, tubular α-alumina supports) with good adhesion, already at 150 C. The effect of the synthesis temperature on sorbents physico-chemical characteristics and sorption properties has been studied with TiO 2 powders prepared under the same conditions as the supported films. The best sorption performance were observed for the powder prepared at 150 C, owing to its higher density of surface sites in comparison with powders prepared at either 250 C or 350 C. Consequently, this synthesis temperature (150 C) was selected for a detailed study of the composite sorbents (TiO 2 /support), in order to assess their sorption performance in continuous treatment processes. The sorption experiments have shown that a column of alumina macroporous foam (Φpore = 400μm) coated with TiO 2 was suitable for processing effluents in dynamic mode with high throughputs. Both macro-pore sizes and column height were revealed as important parameters to be controlled. For the coupled filtration/sorption treatment, TiO 2 membranes exhibit good mechanical strength and are able

  10. Macroporous hydrogels based on 2-hydroxyethyl methacrylate. Part 6: 3D hydrogels with positive and negative surface charges and polyelectrolyte complexes in spinal cord injury repair

    Czech Academy of Sciences Publication Activity Database

    Hejčl, Aleš; Lesný, Petr; Přádný, Martin; Šedý, Jiří; Zámečník, J.; Jendelová, Pavla; Michálek, Jiří; Syková, Eva

    2009-01-01

    Roč. 20, č. 7 (2009), s. 1571-1577 ISSN 0957-4530 R&D Projects: GA AV ČR IAA500390902 Grant - others:GA MŠk(CZ) 1M0538; GA MZd(CZ) 1A8697; EC FP6 project RESCUE(XE) LSHB-CT-2005-518233 Program:1M Institutional research plan: CEZ:AV0Z50390703; CEZ:AV0Z40500505 Keywords : transplantation * biomaterials * macroporous hydrogels Subject RIV: FH - Neurology Impact factor: 1.955, year: 2009

  11. Synthesis and Phase Behavior of Poly(N-isopropylacrylamide-b- Poly(L-Lysine Hydrochloride and Poly(N-Isopropylacrylamide- co-Acrylamide-b-Poly(L-Lysine Hydrochloride

    Directory of Open Access Journals (Sweden)

    Milica Spasojević

    2014-07-01

    Full Text Available The synthesis of poly(N-isopropylacrylamide-b-poly(L-lysine and poly(N- isopropylacrylamide-co-acrylamide-b-poly(L-lysine copolymers was accomplished by combining atom transfer radical polymerization (ATRP and ring opening polymerization (ROP. For this purpose, a di-functional initiator with protected amino group was successfully synthetized. The ATRP of N-isopropylacrylamide yielded narrowly dispersed polymers with consistent high yields (~80%. Lower yields (~50% were observed when narrowly dispersed random copolymers of N-isopropylacrylamide and acrylamide where synthesized. Amino-terminated poly(N-isopropylacrylamide and poly(N-isopropylacrylamide- co-acrylamide were successfully used as macroinitiators for ROP of N6-carbobenzoxy-L- lysine N-carboxyanhydride. The thermal behavior of the homopolymers and copolymers in aqueous solutions was studied by turbidimetry, dynamic light scattering (DLS and proton nuclear magnetic resonance spectroscopy (1H-NMR.

  12. Interfacial electrostatics of poly(vinylamine hydrochloride), poly(diallyldimethylammonium chloride), poly-l-lysine, and poly-l-arginine interacting with lipid bilayers.

    Science.gov (United States)

    McGeachy, A C; Dalchand, N; Caudill, E R; Li, T; Doğangün, M; Olenick, L L; Chang, H; Pedersen, J A; Geiger, F M

    2018-04-25

    Charge densities of cationic polymers adsorbed to lipid bilayers are estimated from second harmonic generation (SHG) spectroscopy and quartz crystal microbalance with dissipation monitoring (QCM-D) measurements. The systems surveyed included poly(vinylamine hydrochloride) (PVAm), poly(diallyldimethylammonium chloride) (PDADMAC), poly-l-lysine (PLL), and poly-l-arginine (PLR), as well as polyalcohol controls. Upon accounting for the number of positive charges associated with each polyelectrolyte, the binding constants and apparent free energies of adsorption as estimated from SHG data are comparable despite differences in molecular masses and molecular structure, with ΔGads values of -61 ± 2, -58 ± 2, -57 ± 1, -52 ± 2, -52 ± 1 kJ mol-1 for PDADMAC400, PDADMAC100, PVAm, PLL, and PLR, respectively. Moreover, we find charge densities for polymer adlayers of approximately 0.3 C m-2 for poly(diallyldimethylammonium chloride) while those of poly(vinylamine) hydrochloride, poly-l-lysine, and poly-l-arginine are approximately 0.2 C m-2. Time-dependent studies indicate that polycation adsorption to supported lipid bilayers is only partially reversible for most of the polymers explored. Poly(diallyldimethylammonium chloride) does not demonstrate reversible binding even over long timescales (>8 hours).

  13. Enrichment and Purification of Syringin, Eleutheroside E and Isofraxidin from Acanthopanax senticosus by Macroporous Resin

    Directory of Open Access Journals (Sweden)

    Yuangang Zu

    2012-07-01

    Full Text Available In order to screen a suitable resin for the preparative simultaneous separation and purification of syringin, eleutheroside E and isofraxidin from Acanthopanax senticosus, the adsorption and desorption properties of 17 widely used commercial macroporous resins were evaluated. According to our results, HPD100C, which adsorbs by the molecular tiers model, was the best macroporous resin, offering higher adsorption and desorption capacities and higher adsorption speed for syringin, eleutheroside E and isofraxidin than other resins. Dynamic adsorption and desorption tests were carried out to optimize the process parameters. The optimal conditions were as follows: for adsorption, processing volume: 24 BV, flow rate: 2 BV/h; for desorption, ethanol–water solution: 60:40 (v/v, eluent volume: 4 BV, flow rate: 3 BV/h. Under the above conditions, the contents of syringin, eleutheroside E and isofraxidin increased 174-fold, 20-fold and 5-fold and their recoveries were 80.93%, 93.97% and 93.79%, respectively.

  14. Proof of concept of an epitaxy-free layer-transfer process for silicon solar cells based on the reorganisation of macropores upon annealing

    International Nuclear Information System (INIS)

    Depauw, V.; Gordon, I.; Beaucarne, G.; Poortmans, J.; Mertens, R.; Celis, J.-P.

    2009-01-01

    To answer the challenge of less expensive renewable electricity, the photovoltaics community is focusing on producing thinner silicon solar cells. A few years ago, in the field of silicon-on-nothing structures, micron-thick monocrystalline layers suspended over their parent wafer were produced by high-temperature annealing of specific arrays of macropores. Those macropores reorganise into one single void and leave a thin overlayer on top. Since this method may be an inexpensive way of fabricating high-quality silicon films, this paper investigates its potential for photovoltaic applications. In particular, we investigated if large surfaces can be produced and transferred to foreign substrates with this method. We fabricated basic solar cells, without rear-surface passivation, on 5 cm x 5 cm-large and 1-μm-thick films transferred to glass, that showed energy-conversion efficiencies up to 2.6%. These cells demonstrate the feasibility of the presented concept as a layer-transfer process for solar-cell application. After formation by annealing, the film is only barely attached to its parent wafer, but can still safely be handled provided that any abrupt gas flow or pumping to vacuum is avoided. After transfer and permanent bonding, the sample can be handled as any bulk wafer.

  15. Dual-Function Electrocatalytic and Macroporous Hollow-Fiber Cathode for Converting Waste Streams to Valuable Resources Using Microbial Electrochemical Systems

    KAUST Repository

    Katuri, Krishna; Kalathil, Shafeer; Ragab, Ala'a; Bian, Bin; AlQahtani, Manal Faisal; Pant, Deepak; Saikaly, Pascal

    2018-01-01

    Dual-function electrocatalytic and macroporous hollow-fiber cathodes are recently proposed as promising advanced material for maximizing the conversion of waste streams such as wastewater and waste CO2 to valuable resources (e.g., clean freshwater, energy, value-added chemicals) in microbial electrochemical systems. The first part of this progress report reviews recent developments in this type of cathode architecture for the simultaneous recovery of clean freshwater and energy from wastewater. Critical insights are provided on suitable materials for fabricating these cathodes, as well as addressing some challenges in the fabrication process with proposed strategies to overcome them. The second and complementary part of the progress report highlights how the unique features of this cathode architecture can solve one of the intrinsic bottlenecks (gas-liquid mass transfer limitation) in the application of microbial electrochemical systems for CO2 reduction to value-added products. Strategies to further improve the availability of CO2 to microbial catalysts on the cathode are proposed. The importance of understanding microbe-cathode interactions, as well as electron transfer mechanisms at the cathode-cell and cell-cell interface to better design dual-function macroporous hollow-fiber cathodes, is critically discussed with insights on how the choice of material is important in facilitating direct electron transfer versus mediated electron transfer.

  16. Immobilized Candida antarctica lipase B on ZnO nanowires/macroporous silica composites for catalyzing chiral resolution of (R,S)-2-octanol.

    Science.gov (United States)

    Shang, Chuan-Yang; Li, Wei-Xun; Zhang, Rui-Feng

    2014-01-01

    ZnO nanowires were successfully introduced into a macroporous SiO2 by in situ hydrothermal growth in 3D pores. The obtained composites were characterized by SEM and XRD, and used as supports to immobilize Candida antarctica lipase B (CALB) through adsorption. The high specific surface area (233 m(2)/g) and strong electrostatic interaction resulted that the average loading amount of the composite supports (196.8 mg/g) was 3-4 times of that of macroporous SiO2 and approximate to that of a silica-based mesoporous material. Both adsorption capacity and the activity of the CALB immobilized on the composite supports almost kept unchanged as the samples were soaked in buffer solution for 48 h. The chiral resolution of 2-octanol was catalyzed by immobilized CALB. A maximum molar conversion of 49.1% was achieved with 99% enantiomeric excess of (R)-2-octanol acetate under the optimal condition: a reaction using 1.0 mol/L (R,S)-2-octanol, 2.0 mol/L vinyl acetate and 4.0 wt.% water content at 60°C for 8h. After fifteen recycles the immobilized lipase could retain 96.9% of relative activity and 93.8% of relative enantioselectivity. Copyright © 2014 Elsevier Inc. All rights reserved.

  17. Sucrose-assisted synthesis of three-dimensionally ordered macroporous CeO{sub 2} and its use as a support for promotional catalytic performance of CO oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Zhi, E-mail: zhiliu@lnnu.edu.cn; Tan, Xiuli; Lv, Cong

    2013-10-15

    In this work, several three-dimensionally ordered macroporous (3DOM) CeO{sub 2} having hierarchical pore structure were successfully prepared via a dual ‘hard-soft’ templating strategy using Ce(NO{sub 3}){sub 3}·6H{sub 2}O containing sucrose as the ceria precursor. The resulting CeO{sub 2} samples were characterized by N{sub 2} adsorption–desorption analysis, scanning electron microscopy, and transmission electron microscopy, which showed that the hierarchical 3DOM CeO{sub 2} possessed interconnected networks of the ordered macropore structures with large mesopores, and both the BET surface area and pore volume increased significantly compared with the conventional 3DOM CeO{sub 2}. The content of sucrose had a great effect on the textural parameters of the 3DOM CeO{sub 2}. The improved textural parameters should be attributed to the emergence of mesopores in the interconnected three-dimensional skeleton, which were formed by oxidative removal of carbon produced from carbonization of sucrose. The hierarchical 3DOM CeO{sub 2} exhibited a superior performance to the conventional 3DOM or bulk CeO{sub 2} when used as supports for Ir catalysts in CO oxidation.

  18. Adsorption kinetics, isotherm, and thermodynamics studies of acetyl-11-keto-β-boswellic acids (AKBA) from Boswellia serrata extract using macroporous resin.

    Science.gov (United States)

    Niphadkar, Sonali S; Rathod, Virendra K

    2017-09-14

    An acetyl-11-keto-β-boswellic acid (AKBA) is potent anti-inflammatory agent found in Boswellia serrata oleogum resin. Adsorption characteristics of AKBA from B. serrata were studied using macroporous adsorbent resin to understand separation and adsorption mechanism of targeted molecules. Different macroporous resins were screened for adsorption and desorption of AKBA and Indion 830 was screened as it showed higher adsorption capacity. The kinetic equations were studied and results showed that the adsorption of AKBA on Indion 830 was well fitted to the pseudo first-order kinetic model. The influence of two parameters such as temperature (298, 303, and 308 K) and pH (5-8) on the adsorption process was also studied. The experimental data was further investigated using Langmuir, Freundlich, and Temkin isotherm models. It was observed that Langmuir isotherm model was found to be the best fit for AKBA adsorption by Indion 830 and highest adsorption capacity (50.34 mg/g) was obtained at temperature of 303 K. The values of thermodynamic parameters such as the change of Gibbs free energy (ΔG*), entropy (ΔS*), and enthalpy (ΔH*), indicated that the process of adsorption was spontaneous, favourable, and exothermic.

  19. Dual-Function Electrocatalytic and Macroporous Hollow-Fiber Cathode for Converting Waste Streams to Valuable Resources Using Microbial Electrochemical Systems

    KAUST Repository

    Katuri, Krishna

    2018-04-30

    Dual-function electrocatalytic and macroporous hollow-fiber cathodes are recently proposed as promising advanced material for maximizing the conversion of waste streams such as wastewater and waste CO2 to valuable resources (e.g., clean freshwater, energy, value-added chemicals) in microbial electrochemical systems. The first part of this progress report reviews recent developments in this type of cathode architecture for the simultaneous recovery of clean freshwater and energy from wastewater. Critical insights are provided on suitable materials for fabricating these cathodes, as well as addressing some challenges in the fabrication process with proposed strategies to overcome them. The second and complementary part of the progress report highlights how the unique features of this cathode architecture can solve one of the intrinsic bottlenecks (gas-liquid mass transfer limitation) in the application of microbial electrochemical systems for CO2 reduction to value-added products. Strategies to further improve the availability of CO2 to microbial catalysts on the cathode are proposed. The importance of understanding microbe-cathode interactions, as well as electron transfer mechanisms at the cathode-cell and cell-cell interface to better design dual-function macroporous hollow-fiber cathodes, is critically discussed with insights on how the choice of material is important in facilitating direct electron transfer versus mediated electron transfer.

  20. A multi-scaled hybrid orthopedic implant: bone ECM-shaped Sr-HA nanofibers on the microporous walls of a macroporous titanium scaffold

    Energy Technology Data Exchange (ETDEWEB)

    Han Yong; Zhou Jianhong; Zhang Lan; Xu Kewei, E-mail: yonghan@mail.xjtu.edu.cn [State Key Laboratory for Mechanical Behavior of Materials, Xi' an Jiaotong University, Xi' an 710049 (China)

    2011-07-08

    We report here, for the first time, a novel multi-scaled hybrid orthopedic implant material consisting of a macroporous Ti scaffold, whose macropores' walls have a microporous titania layer which is fully covered with nanofibers of Sr-doped hydroxyapatite (Sr-HA). The microporous titania layer is formed on and within the Ti scaffold by micro-arc oxidation, which firmly binds to the Ti substrate and contains Ca{sup 2+}, Sr{sup 2+} and PO{sub 4}{sup 3-} ions. It is then hydrothermally treated to form Sr-HA nanofibers. During the hydrothermal treatment, Sr-HA nanoprisms nucleate from Ca{sub 0.5}Sr{sub 0.5}TiO{sub 3} pre-formed on the TiO{sub 2} and grow in length to nanofibers at the expense of Ca{sup 2+}, Sr{sup 2+} and PO{sub 4}{sup 3-} ions that migrate from the TiO{sub 2}. These Sr-HA nanofibers construct a network structure similar to the hierarchical organization of bone extracellular matrix (ECM), and the resulting nanofibrous surface displays a firm adhesion to substrate, superhydrophilicity and apatite-inducing ability. The induced apatite prefers to nucleate on the basal-faceted surfaces of Sr-HA nanofibers. The nanofiber-walled scaffold has a great potential for load-bearing orthotopic use.

  1. A multi-scaled hybrid orthopedic implant: bone ECM-shaped Sr-HA nanofibers on the microporous walls of a macroporous titanium scaffold.

    Science.gov (United States)

    Han, Yong; Zhou, Jianhong; Zhang, Lan; Xu, Kewei

    2011-07-08

    We report here, for the first time, a novel multi-scaled hybrid orthopedic implant material consisting of a macroporous Ti scaffold, whose macropores' walls have a microporous titania layer which is fully covered with nanofibers of Sr-doped hydroxyapatite (Sr-HA). The microporous titania layer is formed on and within the Ti scaffold by micro-arc oxidation, which firmly binds to the Ti substrate and contains Ca2+, Sr2+ and PO4(3-) ions. It is then hydrothermally treated to form Sr-HA nanofibers. During the hydrothermal treatment, Sr-HA nanoprisms nucleate from Ca0.5Sr0.5TiO3 pre-formed on the TiO2 and grow in length to nanofibers at the expense of Ca2+, Sr2+ and PO4(3-) ions that migrate from the TiO2. These Sr-HA nanofibers construct a network structure similar to the hierarchical organization of bone extracellular matrix (ECM), and the resulting nanofibrous surface displays a firm adhesion to substrate, superhydrophilicity and apatite-inducing ability. The induced apatite prefers to nucleate on the basal-faceted surfaces of Sr-HA nanofibers. The nanofiber-walled scaffold has a great potential for load-bearing orthotopic use.

  2. Zero-order release of lysozyme from (poly)ethylene glycol)/poly(butylene terephthalate) matrices

    NARCIS (Netherlands)

    Bezemer, J.M.; Radersma, R.; Grijpma, Dirk W.; Dijkstra, Pieter J.; Feijen, Jan; van Blitterswijk, Clemens

    2000-01-01

    Protein release from a series of biodegradable poly(ether ester) multiblock copolymers, based on poly(ethylene glycol) (PEG) and poly(butylene terephthalate) (PBT) was investigated. Lysozyme-containing PEG/PBT films and microspheres were prepared using an emulsion technique. Proteins were

  3. Synthesis by ATRP of poly(ethylene-co-butylene)-block-polystyrene, poly(ethylene-co-butylene)-block-poly(4-acetoxystyrene) and its hydrolysis product poly(ethylene-co-butylene)-block-poly(hydroxystyrene)

    DEFF Research Database (Denmark)

    Jankova, Katja; Kops, Jørgen; Chen, Xianyi

    1999-01-01

    Diblock copolymers of poly(ethylene-co-butylene) and polystyrene or poly(4-acetoxystyrene) are synthesized by atom transfer radical polymerization (ATRP) using a 2-bromopropionic ester macroinitiator prepared from commercial monohydroxyl functional narrow dispersity hydrogenated polybutadiene...

  4. Ionic conducting poly-benzimidazoles

    International Nuclear Information System (INIS)

    Jouanneau, J.

    2006-11-01

    Over the last years, many research works have been focused on new clean energy systems. Hydrogen fuel cell seems to be the most promising one. However, the large scale development of this technology is still limited by some key elements. One of them is the polymer electrolyte membrane 'Nafion' currently used, for which the ratio performance/cost is too low. The investigations we carried out during this thesis work are related to a new class of ionic conducting polymer, the sulfonated poly-benzimidazoles (sPBI). Poly-benzimidazoles (PBI) are aromatic heterocyclic polymers well-known for their excellent thermal and chemical stability. Ionic conduction properties are obtained by having strong acid groups (sulfonic acid SO 3 H) on the macromolecular structure. For that purpose, we first synthesized sulfonated monomers. Their poly-condensation with an appropriate non-sulfonated co-monomer yields to sPBI with sulfonation range from 0 to 100 per cent. Three different sPBI structures were obtained, and verified by appropriate analytical techniques. We also showed that the protocol used for the synthesis resulted in high molecular weights polymers. We prepared ionic conducting membrane by casting sPBI solutions on glass plates. Their properties of stability, water swelling and ionic conductivity were investigated. Surprisingly, the behaviour of sPBI was quite different from the other sulfonated aromatic polymers with same amount of SO 3 H, their stability was much higher, but their water swelling and ionic conductivity were quite low. We attributed these differences to strong ionic interactions between the sulfonic acid groups and the basic benzimidazole groups of our polymers. However, we managed to solve this problem synthesizing very highly sulfonated PBI, obtaining membranes with a good balance between all the properties necessary. (author)

  5. Poly(ethylene oxide) functionalization

    Science.gov (United States)

    Pratt, Russell Clayton

    2014-04-08

    A simple procedure is provided by which the hydroxyl termini of poly(ethylene oxide) can be appended with functional groups to a useful extent by reaction and precipitation. The polymer is dissolved in warmed toluene, treated with an excess of organic base and somewhat less of an excess of a reactive acylating reagent, reacted for several hours, then precipitated in isopropanol so that the product can be isolated as a solid, and salt byproducts are washed away. This procedure enables functionalization of the polymer while not requiring laborious purification steps such as solvent-solvent extraction or dialysis to remove undesirable side products.

  6. The thermal degradation of poly(iso-butyl methacrylate and poly(sec-butyl methacrylate

    Directory of Open Access Journals (Sweden)

    IVANKA G. POPOVIC

    2000-12-01

    Full Text Available The non-oxidative thermal degradation of poly(iso-butyl methacrylate and poly(sec-butyl methacrylate was investigated by studying changes in the polymer residue. Due to the different number of b-hydrogens in their ester substituents, these two polymeric isomers behave differently when subjected to elevated temperatures. Poly(iso-butyl methacrylate degrades quantitatively by depolymerisation with zip lengths of the same order of magnitude as those of poly(methyl methacrylate. Poly(sec-butyl methacrylate degrades by a combined degradation mechanism of depolymerisation and de-esterification. De-esterification becomes a significant thermolysis route at temperatures higher than 240°C.

  7. Synthesis and aqueous phase behavior of thermoresponsive biodegradable poly(D,L-3-methylglycolide)-block-poly(ethyelene glycol)-block-poly(D,L-3-methylglycolide) triblock copolymers

    NARCIS (Netherlands)

    Zhong, Zhiyuan; Dijkstra, Pieter J.; Feijen, Jan; Kwon, Young-Min; Bae, You Han; Kim, Sung Wan

    2002-01-01

    Novel biodegradable thermosensitive triblock copolymers of poly(D,L-3-methylglycolide)-block-poly(ethylene glycol)-block-poly(D,L-3-methylglycolide) (PMG-PEG-PMG) have been synthesized. Ring-opening polymerization of D,L-3-methyl-glycolide (MG) initiated with poly(ethylene glycol) (PEG) and

  8. Synthesis and characterization of poly aniline/wood and poly aniline/carbon composites

    International Nuclear Information System (INIS)

    Kanwal, F.; Siddiqi, S.A.; Tasleem, S.

    2009-01-01

    Conducting polymers have shown many applications in the field of nano science, nano technology and nuclear science. Poly aniline (PAN I) is the most studied conducting polymer due to its environmental stability, easy availability of its raw materials, and simple synthesis. We have synthesized poly aniline and two of its conducting composites i.e., poly aniline-carbon and poly aniline-wood in acidic medium (HCI) using K/sub 2/Cr/sub 2/O/sub 7/ as oxidizing agent. All samples were characterized by FTIR and four-probe d.c. conductivity methods The synthesis was carried out at two different temperatures (0 degree C and -5 degree C) and it was found that the yield and conductivity were maximum at lower temperature (-5 degree C). The poly aniline-carbon composites showed enhanced conductivity whereas poly aniline-wood composites showed reduced conductivity when compared with the conductivity of pure poly aniline. (author)

  9. Hole drift mobility in poly(hexylphenylsilane)

    International Nuclear Information System (INIS)

    Kunimi, Y.; Seki, S.; Tagawa, S.

    2000-01-01

    Poly(n-alkylphenylsilane)s in which n-alkyl were changed from methyl to octyl were polymerized. Hole transport properties of poly(alkyllphenylsilane)s were systematically studied by the DC time-of-flight (TOF) technique. While the hole drift mobility of poly(methylphenylsilane) increased monotonously in entire field, those of poly(hexylphenylsilane) and poly(octylphenylsilane) decreased with increase in the field strength. Temperature dependence of hole drift mobility in those polymers was small. On the basis of Baessler's disorder formalism the mobility was analyzed quantitatively to disserve complex contributions of charge transport. The analyzed results indicated that with increase in the length of n-alkyl side-groups, the energetic disorder of hopping sites became smaller and the disorder of distance between hopping sites became larger. These results were supported by the results obtained by UV absorption measurement and positron annihilation life-time spectroscopy measurement. (author)

  10. Modification of macroporous membranes by graft co-polymerization induced by pre-irradiation with an electron accelerator; Modificacion de membranas macroporosas para la recuperacion de protemas por intercambio ionico

    Energy Technology Data Exchange (ETDEWEB)

    Grasselli, M [Buenos Aires Univ. (Argentina). Facultad de Farmacia y Bioquimica; Yoshii, Fumio [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Chemistry Research Establishment

    1999-07-01

    Glycidyl methacrylate (GMA) and N,N-dimethylacrylamide (DMAA) have been co-grafted on hollow fiber membranes of macroporous polyethylene. Grafted copolymers have been obtained with different ratios of the monomers (molar ratio between 0 and 2 DMAA/GMA). The properties of the modified membranes are studied.

  11. A macroporous heparin-releasing silk fibroin scaffold improves islet transplantation outcome by promoting islet revascularisation and survival.

    Science.gov (United States)

    Mao, Duo; Zhu, Meifeng; Zhang, Xiuyuan; Ma, Rong; Yang, Xiaoqing; Ke, Tingyu; Wang, Lianyong; Li, Zongjin; Kong, Deling; Li, Chen

    2017-09-01

    Islet transplantation is considered the most promising therapeutic option with the potential to cure diabetes. However, efficacy of current clinical islet transplantation is limited by long-term graft dysfunction and attrition. We have investigated the therapeutic potential of a silk fibroin macroporous (SF) scaffold for syngeneic islet transplantation in diabetic mice. The SF scaffold was prepared via lyophilisation, which enables incorporation of active compounds including cytokines, peptide and growth factors without compromising their biological activity. For the present study, a heparin-releasing SF scaffold (H-SF) in order to evaluate the versatility of the SF scaffold for biological functionalisation. Islets were then co-transplanted with H-SF or SF scaffolds in the epididymal fat pad of diabetic mice. Mice from both H-SF and SF groups achieved 100% euglycaemia, which was maintained for 1year. More importantly, the H-SF-islets co-transplantation led to more rapid reversal of hyperglycaemia, complete normalisation of glucose responsiveness and lower long-term blood glucose levels. This superior transplantation outcome is attributable to H-SF-facilitated islet revascularisation and cell proliferation since significant increase of islet endocrine and endothelial cells proliferation was shown in grafts retrieved from H-SF-islets co-transplanted mice. Better intra-islet vascular reformation was also evident, accompanied by VEGF upregulation. In addition, when H-SF was co-transplanted with islets extracted from vegfr2-luc transgenic mice in vivo, sustained elevation of bioluminescent signal that corresponds to vegfr2 expression was collected, implicating a role of heparin-dependent activation of endogenous VEGF/VEGFR2 pathway in promoting islet revascularisation and proliferation. In summary, the SF scaffolds provide an open platform as scaffold development for islet transplantation. Furthermore, given the pro-angiogenic, pro-survival and minimal post

  12. Immunocapture of CD133-positive cells from human cancer cell lines by using monodisperse magnetic poly(glycidyl methacrylate) microspheres containing amino groups

    Energy Technology Data Exchange (ETDEWEB)

    Kuan, Wei-Chih [Department of Chemical Engineering, Systems Biology and Tissue Engineering Research Center, National Chung Cheng University, Minhisung 621, Taiwan (China); Horák, Daniel, E-mail: horak@imc.cas.cz [Institute of Macromolecular Chemistry, Academy of Sciences of the Czech Republic, Heyrovsky Sq. 2, 162 06 Prague 6 (Czech Republic); Plichta, Zdeněk [Institute of Macromolecular Chemistry, Academy of Sciences of the Czech Republic, Heyrovsky Sq. 2, 162 06 Prague 6 (Czech Republic); Lee, Wen-Chien [Department of Chemical Engineering, Systems Biology and Tissue Engineering Research Center, National Chung Cheng University, Minhisung 621, Taiwan (China)

    2014-01-01

    Magnetic poly(glycidyl methacrylate)-based macroporous microspheres with an average particle size of 4.2 μm were prepared using a modified multi-step swelling polymerization method and by introducing amino functionality on their surfaces. Antibody molecules were oxidized on their carbohydrate moieties and bound to the amino-containing magnetic microspheres via a site-directed procedure. CD133-positive cells could be effectively captured from human cancer cell lines (HepG2, HCT116, MCF7, and IMR-32) by using magnetic microspheres conjugated to an anti-human CD133 antibody. After further culture, the immunocaptured CD133-expressing cells from IMR-32 proliferated and gradually detached from the magnetic microspheres. Flow-cytometric analysis confirmed the enrichment of CD133-expressing cells by using the antibody-bound magnetic microspheres. Such microspheres suitable for immunocapture are very promising for cancer diagnosis because the CD133-expressing cells in cancer cell lines have been suggested to be cancer stem cells. - Highlights: • Multi-step swelling polymerization produced poly(glycidyl methacrylate) microspheres. • Anti-human CD133 antibodies were bound to the amino-containing magnetic microspheres. • CD133-positive cells were effectively captured from human cancer cell lines. • Immunocaptured CD133-expressing cells proliferated and were detached from microspheres. • Enrichment of CD133-expressing cells was confirmed by flow-cytometric analysis.

  13. Removal of 2,4-dichlorophenol using cyclodextrin-ionic liquid polymer as a macroporous material: Characterization, adsorption isotherm, kinetic study, thermodynamics

    Energy Technology Data Exchange (ETDEWEB)

    Raoov, Muggundha [University of Malaya Centre for Ionic Liquids, Department of Chemistry, Faculty of Science, University of Malaya, Kuala Lumpur 50603 (Malaysia); Department of Chemistry, Faculty of Science, University of Malaya, Kuala Lumpur 50603 (Malaysia); Advanced Medical and Dental Institute, University of Science Malaysia, No. 1–8 (Lot 8), Persiaran Seksyen 4/1, Bandar Putra Bertam, Kepala Batas, Pulau Pinang 13200 (Malaysia); Mohamad, Sharifah, E-mail: sharifahm@um.edu.my [University of Malaya Centre for Ionic Liquids, Department of Chemistry, Faculty of Science, University of Malaya, Kuala Lumpur 50603 (Malaysia); Department of Chemistry, Faculty of Science, University of Malaya, Kuala Lumpur 50603 (Malaysia); Abas, Mohd Radzi [Department of Chemistry, Faculty of Science, University of Malaya, Kuala Lumpur 50603 (Malaysia)

    2013-12-15

    Highlights: • βCD-BIMOTs-TDI exhibits macropore size (77.66 nm) with 1.254 m{sup 2} g{sup −1} surface area. • Freundlich isotherm and pseudo-second order kinetics fit well the adsorption process. • Removal was optimum at pH 6 with 83% and reached equilibrium at 80 mg L{sup −1}. • Entropy (ΔS°) and heat of adsorption (ΔH°) estimated as −55.99 J/K mol and −18.10 J/mol. • Inclusion complex and π–π interaction were found to be dominant at pH 6. -- Abstract: Cyclodextrin-ionic liquid polymer (βCD-BIMOTs-TDI) was firstly synthesized using functionalized β-Cyclodextrin (CD) with 1-benzylimidazole (BIM) to form monofunctionalized CD (βCD-BIMOTs) and was further polymerized using toluene diisocyanate (TDI) linker to form insoluble βCD-BIMOTs-TDI. SEM characterization result shows that βCD-BIMOTs-TDI exhibits macropore size while the BET result shows low surface area (1.254 m{sup 2} g{sup −1}). The unique properties of the ILs allow us to produce materials with different morphologies. The adsorption isotherm and kinetics of 2,4-dichlorophenol (2,4-DCP) onto βCD-BIMOTs-TDI is studied. Freundlich isotherm and pseudo-second order kinetics are found to be the best to represent the data for 2,4-DCP adsorption on the βCD-BIMOTs-TDI. The presence of macropores decreases the mass transfer resistance and increases the adsorption process by reducing the diffusion distance. The change in entropy (ΔS°) and heat of adsorption (ΔH°) for 2,4-DCP on βCD-BIMOTs-TDI were estimated as −55.99 J/Kmol and −18.10 J/mol, respectively. The negative value of Gibbs free energy (ΔG°) indicates that the adsorption process is thermodynamically feasible, spontaneous and chemically controlled. Finally, the interactions between the cavity of βCD-BIMOTs and 2,4-DCP are investigated and the results shows that the inclusion of the complex formation and π–π interaction are the main processes involved in the adsorption process.

  14. Study of the processes of degradation of the optical properties of mesoporous and macroporous silicon upon exposure to simulated solar radiation

    Energy Technology Data Exchange (ETDEWEB)

    Levitskii, V. S., E-mail: lev-vladimir@yandex.ru [St. Petersburg State Electrotechnical University “LETI” (Russian Federation); Lenshin, A. S., E-mail: lenshinas@phys.vsu.ru; Seredin, P. V. [Voronezh State University (Russian Federation); Terukov, E. I. [St. Petersburg State Electrotechnical University “LETI” (Russian Federation)

    2015-11-15

    The effect of solar radiation on the surface composition of mesoporous and macroporous silicon is studied by infrared spectroscopy, Raman spectroscopy, and photoluminescence measurements in order to analyze the possibility of using these materials as a material for solar-power engineering. The studies are conducted in the laboratory environment, with the use of a solar-radiation simulator operating under conditions close to the working conditions of standard silicon solar cells. The studies show that, in general, the materials meet the requirements of solar-power engineering, if it is possible to preclude harmful effects associated with the presence of heat-sensitive and photosensitive bonds at the nanomaterial surface by standard processing methods.

  15. Biodiesel production from transesterification of palm oil with methanol over CaO supported on bimodal meso-macroporous silica catalyst.

    Science.gov (United States)

    Witoon, Thongthai; Bumrungsalee, Sittisut; Vathavanichkul, Peerawut; Palitsakun, Supaphorn; Saisriyoot, Maythee; Faungnawakij, Kajornsak

    2014-03-01

    Calcium oxide-loaded porous materials have shown promise as catalysts in transesterification. However, the slow diffusion of bulky triglycerides through the pores limited the activity of calcium oxide (CaO). In this work, bimodal meso-macroporous silica was used as a support to enhance the accessibility of the CaO dispersed inside the pores. Unimodal porous silica having the identical mesopore diameter was employed for the purpose of comparison. Effects of CaO content and catalyst pellet size on the yield of fatty acid methyl esters (FAME) were investigated. The basic strength was found to increase with increasing the CaO content. The CaO-loaded bimodal porous silica catalyst with the pellet size of 325μm achieved a high %FAME of 94.15 in the first cycle, and retained an excellent %FAME of 88.87 after five consecutive cycles. Copyright © 2014 Elsevier Ltd. All rights reserved.

  16. Preparation, Characterization and Permeation Behavior of Poly(methyl acrylate-Poly(dimethyl siloxane-Poly(methyl acrylate Block Copolymer/Poly(vinyl acetate Blend Membranes

    Directory of Open Access Journals (Sweden)

    Mohammad Ali Semsarzadeh

    2015-03-01

    Full Text Available Structure of polymeric materials is of the most important factors in determination of the characteristics and properties of the membranes. Various research and developments on polymeric membranes confirm the direct correlation between structure-properties of polymeric membranes. In this research, the structural outcome of poly(methyl acrylate-poly(dimethyl siloxane-poly(methyl acrylate/poly(vinyl acetate blend membranes and its relationship with gas permeation behavior of the blends were investigated. The flexible block copolymer of poly(methyl acrylate-poly(dimethyl siloxane-poly(methyl acrylate (PMA-PDMS-PMA was synthesized via atom transfer radical polymerization. Morphology and chemical structure of the synthesized block copolymer was investigated by Fourier transform infrared spectroscopy, proton nuclear magnetic resonance, gel permeation chromatography, X-ray diffraction analysis, differential scanning calorimetry and scanning electron microscopy. Blend membranes of PMA-PDMS-PMA and poly(vinyl acetate (PVAc were prepared by solution casting method in different compositions. By adding poly(vinyl acetate to PMA-PDMS-PMA block copolymer, the selectivity of the membranes for carbon dioxide/methane pair gases were increased by 55%. Fractional free volume (an indication of chain packing efficiency in blend membranes and dielectric constant (an indication of the molar volume and molar polarization of the blend membranes were obtained as the factors reflected the microstructural effect of PMA-PDMS-PMA and PVAc blend membranes. The efforts were directed toward expressing more precise structure-properties relationship of PMA-PDMS-PMA/PVAc blend membranes. The experimental permeability values of the blend membranes reported in this research were compared with the modified logarithmic model. The modified logarithmic model was evaluated for other blend membranes.

  17. Morphological and magnetic properties of sol-gel synthetized meso and macroporous spheres of barium hexaferrite (BaFe{sub 12}O{sub 19})

    Energy Technology Data Exchange (ETDEWEB)

    Torres-Cadenas, S., E-mail: storres_c@hotmail.com [Instituto de Investigaciones Metalúrgicas y Materiales, UMSNH, Edificio U, Ciudad Universitaria, Santiago Tapia 403, Colonia Centro, 58030 Morelia (Mexico); Reyes-Gasga, José, E-mail: jreyes@fisica.unam.mx [Instituto de Física, UNAM, Circuito de la Investigación s/n, Ciudad Universitaria, 04510 Coyoacán, México, D.F. (Mexico); Bravo-Patiño, A., E-mail: brapal@hotmail.com [Centro Multidisciplinario de Estudios en Biotecnología (CMEB) de la FMVZ, UMSNH, Posta Zootécnica, km. 8.5 carretera Morelia-Zinapecuaro, C.P. 58890 col. La Palma, Tarimbaro, Michoacán (Mexico); Betancourt, I., E-mail: israelb@iim.unam.mx [Instituto de Investigaciones en Materiales, UNAM, Ciudad de México C.P. 04510 (Mexico); Contreras-García, M.E., E-mail: eucontre@gmail.com [Instituto de Investigaciones Metalúrgicas y Materiales, UMSNH, Edificio U, Ciudad Universitaria, Santiago Tapia 403, Colonia Centro, 58030 Morelia (Mexico)

    2017-06-15

    Highlights: • 1.5 µm porous spheres of BaFe{sub 12}O{sub 19} were synthetized by the sol-gel method. • Surfactant Tween20 (C{sub 58}H{sub 114}O{sub 26}) enabled the creation of the mesoporous structure. • Polystyrene spheres (PS) were used as the template for the formation of macropores. • Spheres resembled a nest or ball-of-yarn type of elongated BaFe{sub 12}O{sub 19} crystals. • Magnetic properties are evaluated as function of the calcination temperature. - Abstract: Porous spherical aggregates of barium hexaferrite (BaFe{sub 12}O{sub 19}) with 1.5 µm in diameter were synthetized by the surfactant-assisted sol-gel method. The surfactant Tween20 (C{sub 58}H{sub 114}O{sub 26}), which enables mesoporous structures, as well as polystyrene spheres (PS), as the template agent for the formation of macropores, were used. Two synthetic routes (hereafter named A and B), whose difference was the absence or presence of PS, were followed for synthesis. X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) in high resolution mode (HRTEM) were used for characterization. Size and morphology of the spheres were similar in both cases and they resemble a nest or ball-of-yarn type structure. Pore size and BaFe{sub 12}O{sub 19} crystal size produced by the two routes are different. The magnetic properties of the spheres were evaluated using a vibrating sample magnetometer (VSM) as function of the calcination temperature. The spheres present ferromagnetic behavior in both routes.

  18. Mesopore- and Macropore-Dominant Nitrogen-Doped Hierarchically Porous Carbons for High-Energy and Ultrafast Supercapacitors in Non-Aqueous Electrolytes.

    Science.gov (United States)

    Shao, Rong; Niu, Jin; Liang, Jingjing; Liu, Mengyue; Zhang, Zhengping; Dou, Meiling; Huang, Yaqin; Wang, Feng

    2017-12-13

    Non-aqueous electrolytes (e.g., organic and ionic liquid electrolytes) can undergo high working voltage to improve the energy densities of supercapacitors. However, the large ion sizes, high viscosities, and low ionic conductivities of organic and ionic liquid electrolytes tend to cause the low specific capacitances, poor rate, and cycling performance of supercapacitors based on conventional micropore-dominant activated carbon electrodes, limiting their practical applications. Herein, we propose an effective strategy to simultaneously obtain high power and energy densities in non-aqueous electrolytes via using a cattle bone-derived porous carbon as an electrode material. Because of the unique co-activation of KOH and hydroxyapatite (HA) within the cattle bone, nitrogen-doped hierarchically porous carbon (referred to as NHPC-HA/KOH) is obtained and possesses a mesopore- and macropore-dominant porosity with an ultrahigh specific surface area (2203 m 2 g -1 ) of meso- and macropores. The NHPC-HA/KOH electrodes exhibit superior performance with specific capacitances of 224 and 240 F g -1 at 5 A g -1 in 1.0 M TEABF 4 /AN and neat EMIMBF 4 electrolyte, respectively. The symmetric supercapacitor using NHPC-HA/KOH electrodes can deliver integrated high energy and power properties (48.6 W h kg -1 at 3.13 kW kg -1 in 1.0 M TEABF 4 /AN and 75 W h kg -1 at 3.75 kW kg -1 in neat EMIMBF 4 ), as well as superior cycling performance (over 89% of the initial capacitance after 10 000 cycles at 10 A g -1 ).

  19. Well-Dispersed Nanoscale Zero-Valent Iron Supported in Macroporous Silica Foams: Synthesis, Characterization, and Performance in Cr(VI Removal

    Directory of Open Access Journals (Sweden)

    Chaoxia Zhao

    2017-01-01

    Full Text Available Well-dispersed nanoscale zero-valent iron (NZVI supported inside the pores of macroporous silica foams (MOSF composites (Mx-NZVI has been prepared as the Cr(VI adsorbent by simply impregnating the MOSF matrix with ferric chloride, followed by the chemical reduction with NaHB4 in aqueous solution at ambient atmosphere. Through the support of MOSF, the reactivity and stability of NZVI are greatly improved. Transmission electron microscopy (TEM results show that NZVI particles are spatially well-dispersed with a typical core-shell structure and supported inside MOSF matrix. The N2 adsorption-desorption isotherms demonstrate that the Mx-NZVI composites can maintain the macroporous structure of MOSF and exhibit a considerable high surface area (503 m2·g−1. X-ray photoelectron spectroscopy (XPS and powder X-ray diffraction (XRD measurements confirm the core-shell structure of iron nanoparticles composed of a metallic Fe0 core and an Fe(II/Fe(III species shell. Batch experiments reveal that the removal efficiency of Cr(VI can reach 100% when the solution contains 15.0 mg·L−1 of Cr(VI at room temperature. In addition, the solution pH and the composites dosage can affect the removal efficiency of Cr(VI. The Langmuir isotherm is applicable to describe the removal process. The kinetic studies demonstrate that the removal of Cr(VI is consistent with pseudo-second-order kinetic model.

  20. Morphological and magnetic properties of sol-gel synthetized meso and macroporous spheres of barium hexaferrite (BaFe12O19)

    International Nuclear Information System (INIS)

    Torres-Cadenas, S.; Reyes-Gasga, José; Bravo-Patiño, A.; Betancourt, I.; Contreras-García, M.E.

    2017-01-01

    Highlights: • 1.5 µm porous spheres of BaFe 12 O 19 were synthetized by the sol-gel method. • Surfactant Tween20 (C 58 H 114 O 26 ) enabled the creation of the mesoporous structure. • Polystyrene spheres (PS) were used as the template for the formation of macropores. • Spheres resembled a nest or ball-of-yarn type of elongated BaFe 12 O 19 crystals. • Magnetic properties are evaluated as function of the calcination temperature. - Abstract: Porous spherical aggregates of barium hexaferrite (BaFe 12 O 19 ) with 1.5 µm in diameter were synthetized by the surfactant-assisted sol-gel method. The surfactant Tween20 (C 58 H 114 O 26 ), which enables mesoporous structures, as well as polystyrene spheres (PS), as the template agent for the formation of macropores, were used. Two synthetic routes (hereafter named A and B), whose difference was the absence or presence of PS, were followed for synthesis. X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) in high resolution mode (HRTEM) were used for characterization. Size and morphology of the spheres were similar in both cases and they resemble a nest or ball-of-yarn type structure. Pore size and BaFe 12 O 19 crystal size produced by the two routes are different. The magnetic properties of the spheres were evaluated using a vibrating sample magnetometer (VSM) as function of the calcination temperature. The spheres present ferromagnetic behavior in both routes.

  1. Polaron Hopping in Nano-scale Poly(dA–Poly(dT DNA

    Directory of Open Access Journals (Sweden)

    Singh Mahi

    2010-01-01

    Full Text Available Abstract We investigate the current–voltage relationship and the temperature-dependent conductance of nano-scale samples of poly(dA–poly(dT DNA molecules. A polaron hopping model has been used to calculate the I–V characteristic of nano-scale samples of DNA. This model agrees with the data for current versus voltage at temperatures greater than 100 K. The quantities G 0 , i 0 , and T 1d are determined empirically, and the conductivity is estimated for samples of poly(dA–poly(dT.

  2. Poly(ester-anhydride):poly(beta-amino ester) micro- and nanospheres: DNA encapsulation and cellular transfection.

    Science.gov (United States)

    Pfeifer, Blaine A; Burdick, Jason A; Little, Steve R; Langer, Robert

    2005-11-04

    Poly(ester-anhydride) delivery devices allow flexibility regarding carrier dimensions (micro- versus nanospheres), degradation rate (anhydride versus ester hydrolysis), and surface labeling (through the anhydride functional unit), and were therefore tested for DNA encapsulation and transfection of a macrophage P388D1 cell line. Poly(l-lactic acid-co-sebacic anhydride) and poly(l-lactic acid-co-adipic anhydride) were synthesized through melt condensation, mixed with 25 wt.% poly(beta-amino ester), and formulated with plasmid DNA (encoding firefly luciferase) into micro- and nanospheres using a double emulsion/solvent evaporation technique. The micro- and nanospheres were then characterized (size, morphology, zeta potential, DNA release) and assayed for DNA encapsulation and cellular transfection over a range of poly(ester-anhydride) copolymer ratios. Poly(ester-anhydride):poly(beta-amino ester) composite microspheres (6-12 microm) and nanospheres (449-1031 nm), generated with copolymers containing between 0 and 25% total polyanhydride content, encapsulated plasmid DNA (>or=20% encapsulation efficiency). Within this polyanhydride range, poly(adipic anhydride) copolymers provided DNA encapsulation at an increased anhydride content (10%, microspheres; 10-25%, nanospheres) compared to poly(sebacic anhydride) copolymers (1%, microspheres and nanospheres) with cellular transfection correlating with the observed DNA encapsulation.

  3. Poly-thiosemicarbazide membrane for gold recovery

    KAUST Repository

    Villalobos, Luis Francisco; Yapici, Tahir; Peinemann, Klaus-Viktor

    2014-01-01

    A novel polymeric membrane adsorber with a high density of adsorption sites that can selectively capture Au(III) ions, is proposed as an efficient alternative to recover gold from dilute solutions. Poly-thiosemicarbazide (PTSC), a polymer

  4. Lignin poly(lactic acid) copolymers

    Energy Technology Data Exchange (ETDEWEB)

    Olsson, Johan Vilhelm; Chung, Yi-Lin; Li, Russell Jingxian; Waymouth, Robert; Sattely, Elizabeth; Billington, Sarah; Frank, Curtis W.

    2017-02-14

    Provided herein are graft co-polymers of lignin and poly(lactic acid) (lignin-g-PLA copolymer), thermoset and thermoplastic polymers including them, methods of preparing these polymers, and articles of manufacture including such polymers.

  5. Thromboresistance of functionalized poly(methylmethacrylate): the ...

    Indian Academy of Sciences (India)

    Thrombogenicity; functional group; poly(methylmethacrylate); surface charge; sulphonate. 1. Introduction ... proteins.2 Thus, the interaction of a polymer with the blood results into the .... adsorption process due to its electrostatic forces. 4.

  6. New Linear and Star-Shaped Thermogelling Poly([R]-3-hydroxybutyrate) Copolymers.

    Science.gov (United States)

    Barouti, Ghislaine; Liow, Sing Shy; Dou, Qingqing; Ye, Hongye; Orione, Clément; Guillaume, Sophie M; Loh, Xian Jun

    2016-07-18

    The synthesis of multi-arm poly([R]-3-hydroxybutyrate) (PHB)-based triblock copolymers (poly([R]-3-hydroxybutyrate)-b-poly(N-isopropylacrylamide)-b-[[poly(methyl ether methacrylate)-g-poly(ethylene glycol)]-co-[poly(methacrylate)-g-poly(propylene glycol)

  7. Biomimetic scaffolds based on hydroxyapatite nanorod/poly(D,L) lactic acid with their corresponding apatite-forming capability and biocompatibility for bone-tissue engineering.

    Science.gov (United States)

    Nga, Nguyen Kim; Hoai, Tran Thanh; Viet, Pham Hung

    2015-04-01

    This study presents a facile synthesis of biomimetic hydroxyapatite nanorod/poly(D,L) lactic acid (HAp/PDLLA) scaffolds with the use of solvent casting combined with a salt-leaching technique for bone-tissue engineering. Field emission scanning electron microscopy, Fourier transform infrared spectroscopy, and energy-dispersive X-ray spectroscopy were used to observe the morphologies, pore structures of synthesized scaffolds, interactions between hydroxyapatite nanorods and poly(D,L) lactic acid, as well as the compositions of the scaffolds, respectively. Porosity of the scaffolds was determined using the liquid substitution method. Moreover, the apatite-forming capability of the scaffolds was evaluated through simulated body fluid (SBF) incubation tests, whereas the viability, attachment, and distribution of human osteoblast cells (MG 63 cell line) on the scaffolds were determined through alamarBlue assay and confocal laser microscopy after nuclear staining with 4',6-diamidino-2-phenylindole and actin filaments of a cytoskeleton with Oregon Green 488 phalloidin. Results showed that hydroxyapatite nanorod/poly(D,L) lactic acid scaffolds that mimic the structure of natural bone were successfully produced. These scaffolds possessed macropore networks with high porosity (80-84%) and mean pore sizes ranging 117-183 μm. These scaffolds demonstrated excellent apatite-forming capabilities. The rapid formation of bone-like apatites with flower-like morphology was observed after 7 days of incubation in SBFs. The scaffolds that had a high percentage (30 wt.%) of hydroxyapatite demonstrated better cell adhesion, proliferation, and distribution than those with low percentages of hydroxyapatite as the days of culture increased. This work presented an efficient route for developing biomimetic composite scaffolds, which have potential applications in bone-tissue engineering. Copyright © 2015 Elsevier B.V. All rights reserved.

  8. A Piriápolis

    Directory of Open Access Journals (Sweden)

    Luis Alberto Quijano Alpuin

    2013-11-01

    Full Text Available Es Piriápolis una estrella prodigiosa que del cielo una noche se escapó, y escondiendo su estela luminosa entre el mar y la sierra se ocultó.   Forjador de ilusiones y de sueños, solo Piria soñando lo encontró, mas no es suyo a pesar de ser su dueño a nosotros su sueño nos legó.   Como él quisiera contemplarlo y mirarlo igual que él lo miró, a su espíritu quisiera yo pasearlo y a su sueño llevarlo entre los dos.   Recoger las horas de los desalientos y en una mochila poderlo llevar, y sobre las rocas ir dejando al viento las desiluciones que puedan quedar.   Llenarme los ojos de color y espuma gozar en la playa con él al pasar, el gris de la sierra tras la blanca bruma el azul del cielo y el verde del mar.   Luis Alberto Quijano Alpuin (1937- Poeta y folklorista uruguayo

  9. Prediction of Poly(A Sites by Poly(A Read Mapping.

    Directory of Open Access Journals (Sweden)

    Thomas Bonfert

    Full Text Available RNA-seq reads containing part of the poly(A tail of transcripts (denoted as poly(A reads provide the most direct evidence for the position of poly(A sites in the genome. However, due to reduced coverage of poly(A tails by reads, poly(A reads are not routinely identified during RNA-seq mapping. Nevertheless, recent studies for several herpesviruses successfully employed mapping of poly(A reads to identify herpesvirus poly(A sites using different strategies and customized programs. To more easily allow such analyses without requiring additional programs, we integrated poly(A read mapping and prediction of poly(A sites into our RNA-seq mapping program ContextMap 2. The implemented approach essentially generalizes previously used poly(A read mapping approaches and combines them with the context-based approach of ContextMap 2 to take into account information provided by other reads aligned to the same location. Poly(A read mapping using ContextMap 2 was evaluated on real-life data from the ENCODE project and compared against a competing approach based on transcriptome assembly (KLEAT. This showed high positive predictive value for our approach, evidenced also by the presence of poly(A signals, and considerably lower runtime than KLEAT. Although sensitivity is low for both methods, we show that this is in part due to a high extent of spurious results in the gold standard set derived from RNA-PET data. Sensitivity improves for poly(A sites of known transcripts or determined with a more specific poly(A sequencing protocol and increases with read coverage on transcript ends. Finally, we illustrate the usefulness of the approach in a high read coverage scenario by a re-analysis of published data for herpes simplex virus 1. Thus, with current trends towards increasing sequencing depth and read length, poly(A read mapping will prove to be increasingly useful and can now be performed automatically during RNA-seq mapping with ContextMap 2.

  10. Gentamicin-loaded poly(lactic-co-glycolic acid) microparticles for the prevention of maxillofacial and orthopedic implant infections

    International Nuclear Information System (INIS)

    Flores, Claudia; Degoutin, Stephanie; Chai, Feng; Raoul, Gwenael; Hornez, Jean-Chritophe; Martel, Bernard; Siepmann, Juergen; Ferri, Joel; Blanchemain, Nicolas

    2016-01-01

    Trauma and orthopedic surgery can cause infections as any open surgical procedures. Such complications occur in only1 to 5% of the cases, but the treatment is rather complicated due to bacterial biofilm formation and limited drug access to the site of infection upon systemic administration. An interesting strategy to overcome this type of complications is to prevent bacterial proliferation and biofilm formation via the local and controlled release of antibiotic drugs from the implant itself. Obviously, the incorporation of the drug into the implant should not affect the latter's biological and mechanical properties. In this context, we optimized the preparation process for gentamicin-loaded poly(lactic-co-glycolic acid) (PLGA) microparticles, which can be incorporated in the macropores of calcium phosphate-based bone substitutes. Microparticles were prepared using a double emulsion solvent extraction/evaporation technique. The processing parameters were optimized in order to provide an average microparticle size of about 60 μm, allowing for incorporation inside the macropores (100 μm) of the hydroxyapatite scaffold. Gentamicin-loaded PLGA microparticles showed a sustained release for 25–30 days and a rapid antibacterial activity due to a burst effect, the extent of which was controlled by the initial loading of the microparticles. SEM pictures revealed a highly porous microparticle structure, which can help to reduce the micro environmental pH drop and autocatalytic effects. The biological evaluation showed the cytocompatibility and non-hemolytic property of the microparticles, and the antibacterial activity against Staphylococcus aureus under the given conditions. - Highlights: • The optimization of microparticle preparation parameters allows to obtain a size compatible with the bone substitute porosity • PDL% has a direct impact on the burst effect, a control release of gentamicin was obtained • The incorporation of microparticles into the macroporosity

  11. Gentamicin-loaded poly(lactic-co-glycolic acid) microparticles for the prevention of maxillofacial and orthopedic implant infections

    Energy Technology Data Exchange (ETDEWEB)

    Flores, Claudia [Univ. Lille, 59000 Lille (France); INSERM U1008, Controlled Drug Delivery Systems and Biomaterials, 59000 Lille (France); Degoutin, Stephanie [Univ. Lille, 59000 Lille (France); UMET, Ingénierie des Systèmes Polymères, Université de Lille 1, 59655 Villeneuve d' Ascq (France); Chai, Feng [Univ. Lille, 59000 Lille (France); INSERM U1008, Controlled Drug Delivery Systems and Biomaterials, 59000 Lille (France); Raoul, Gwenael [Univ. Lille, 59000 Lille (France); INSERM U1008, Controlled Drug Delivery Systems and Biomaterials, 59000 Lille (France); Service Chirurgie Maxillo-Faciale, CHRU de Lille, 59000 Lille (France); Hornez, Jean-Chritophe [Laboratoire des Matériaux Céramiques et Procédés Associés (LMCPA), Université de Valenciennes, 59300 Valenciennes (France); Martel, Bernard [Univ. Lille, 59000 Lille (France); UMET, Ingénierie des Systèmes Polymères, Université de Lille 1, 59655 Villeneuve d' Ascq (France); Siepmann, Juergen [Univ. Lille, 59000 Lille (France); INSERM U1008, Controlled Drug Delivery Systems and Biomaterials, 59000 Lille (France); Ferri, Joel [Univ. Lille, 59000 Lille (France); INSERM U1008, Controlled Drug Delivery Systems and Biomaterials, 59000 Lille (France); Service Chirurgie Maxillo-Faciale, CHRU de Lille, 59000 Lille (France); Blanchemain, Nicolas, E-mail: nicolas.blanchemain@univ-lille2.fr [Univ. Lille, 59000 Lille (France); INSERM U1008, Controlled Drug Delivery Systems and Biomaterials, 59000 Lille (France)

    2016-07-01

    Trauma and orthopedic surgery can cause infections as any open surgical procedures. Such complications occur in only1 to 5% of the cases, but the treatment is rather complicated due to bacterial biofilm formation and limited drug access to the site of infection upon systemic administration. An interesting strategy to overcome this type of complications is to prevent bacterial proliferation and biofilm formation via the local and controlled release of antibiotic drugs from the implant itself. Obviously, the incorporation of the drug into the implant should not affect the latter's biological and mechanical properties. In this context, we optimized the preparation process for gentamicin-loaded poly(lactic-co-glycolic acid) (PLGA) microparticles, which can be incorporated in the macropores of calcium phosphate-based bone substitutes. Microparticles were prepared using a double emulsion solvent extraction/evaporation technique. The processing parameters were optimized in order to provide an average microparticle size of about 60 μm, allowing for incorporation inside the macropores (100 μm) of the hydroxyapatite scaffold. Gentamicin-loaded PLGA microparticles showed a sustained release for 25–30 days and a rapid antibacterial activity due to a burst effect, the extent of which was controlled by the initial loading of the microparticles. SEM pictures revealed a highly porous microparticle structure, which can help to reduce the micro environmental pH drop and autocatalytic effects. The biological evaluation showed the cytocompatibility and non-hemolytic property of the microparticles, and the antibacterial activity against Staphylococcus aureus under the given conditions. - Highlights: • The optimization of microparticle preparation parameters allows to obtain a size compatible with the bone substitute porosity • PDL% has a direct impact on the burst effect, a control release of gentamicin was obtained • The incorporation of microparticles into the

  12. Gas-permeation properties of poly(ethylene oxide) poly(butylene terephthalate block copolymers

    NARCIS (Netherlands)

    Metz, S.J.; Mulder, M.H.V.; Wessling, Matthias

    2004-01-01

    This paper reports the gas-permeation properties of poly(ethylene oxide) (PEO) poly(butylene terephthalate) (PBT) segmented multiblock copolymers. These block copolymers allow a precise structural modification by the amount of PBT and the PEO segment length, enabling a systematic study of the

  13. Poly(ethylene oxide)–Poly(propylene oxide)-Based Copolymers for ...

    African Journals Online (AJOL)

    Amphiphilic poly(ethylene oxide)–poly(propylene oxide) (PEO–PPO)-based copolymers are thermoresponsive materials having aggregation properties in aqueous medium. As hydrosolubilizers of poorly water-soluble drugs and improved stability of sensitive agents, these materials have been investigated for improvement ...

  14. Poly(N-isopropylacrylamide)–poly(ferrocenylsilane) dual-responsive hydrogels: synthesis, characterization and antimicrobial applications

    NARCIS (Netherlands)

    Sui, Xiaofeng; Feng, Xueling; Di Luca, Andrea; van Blitterswijk, Clemens; Moroni, Lorenzo; Hempenius, Mark A.; Vancso, Gyula J.

    2013-01-01

    Novel hydrogels composed of thermo-responsive poly(N-isopropylacrylamide) (PNIPAM) and redox-responsive poly(ferrocenylsilane) (PFS) macromolecules were formed by photopolymerization. PFS chains bearing acrylate side groups were copolymerized with NIPAM and N,N′-methylenebisacrylamide in

  15. Poly(aniline-co-m-aminobenzoic acid) deposited on poly(vinyl ...

    Indian Academy of Sciences (India)

    Abstract. In this work, we have deposited poly(aniline-co-m-aminobenzoic acid) on poly(vinyl alcohol) (PVA) by in situ ... along the polyaniline (PANI) chain results in self dop- ing of PANI and ..... The value of electrical conductivity is found to be ...

  16. Poly(ethylene oxide) surfactant polymers.

    Science.gov (United States)

    Vacheethasanee, Katanchalee; Wang, Shuwu; Qiu, Yongxing; Marchant, Roger E

    2004-01-01

    We report on a series of structurally well-defined surfactant polymers that undergo surface-induced self-assembly on hydrophobic biomaterial surfaces. The surfactant polymers consist of a poly(vinyl amine) backbone with poly(ethylene oxide) and hexanal pendant groups. The poly(vinyl amine) (PVAm) was synthesized by hydrolysis of poly(N-vinyl formamide) following free radical polymerization of N-vinyl formamide. Hexanal and aldehyde-terminated poly(ethylene oxide) (PEO) were simultaneously attached to PVAm via reductive amination. Surfactant polymers with different PEO:hexanal ratios and hydrophilic/hydrophobic balances were prepared, and characterized by FT-IR, 1H-NMR and XPS spectroscopies. Surface active properties at the air/water interface were determined by surface tension measurements. Surface activity at a solid surface/water interface was demonstrated by atomic force microscopy, showing epitaxially molecular alignment for surfactant polymers adsorbed on highly oriented pyrolytic graphite. The surfactant polymers described in this report can be adapted for simple non-covalent surface modification of biomaterials and hydrophobic surfaces to provide highly hydrated interfaces.

  17. Effect of Sol-Gel Ageing Time on Three Dimensionally Ordered Macroporous Structure of 80SiO2-15CaO-5P2O5 Bioactive Glasses

    Directory of Open Access Journals (Sweden)

    Thanida CHAROENSUK

    2014-04-01

    Full Text Available Three dimensionally ordered macroporous bioactive glasses (3DOM-BGs, namely 80SiO2-15CaO-5P2O5, were synthesized by sol-gel method. PMMA colloidal crystals and non-ionic block copolymers P123 were used as cotemplates. The amorphous 3DOM-BGs had skeletal walls enclosing macropores. Such structure resulted from octahedral and tetrahedral holes of the face-centered cubic (fcc closest packed PMMA templates and windows interconnecting through macropores network. The thicknesses of the walls were around 50 nm – 80 nm and the windows were 90 nm – 110 nm in diameter. These wall thickness is increased by with an increase in ageing time up to 24 h and  then gradually reduced with further increase in aging time. Vibration bands of Si–O–Si and P–O were evident in infrared spectra which are in agreement with EDS spectra indicating Si, P and Ca compositions. After in vitro bioactivity testing by soaking 3DOM-BGs in simulated body fluid at 37 °C, the crystallization of amorphous calcium phosphate layers compatible to the bone component of hydroxyl carbonate apatite were rapidly formed within 3 h. These results indicated that these 3DOM-BGs resembled ideal bone implant materials.DOI: http://dx.doi.org/10.5755/j01.ms.20.1.4755

  18. Immobilisation of enzymes on poly(aniline)-poly(anion) composite films. Preparation of bioanodes for biofuel cell applications.

    Science.gov (United States)

    Simon, Evelyne; Halliwell, Catherine M; Toh, Chee Seng; Cass, Anthony E G; Bartlett, Philip N

    2002-01-01

    Immobilisation of enzymes is important for applications such as biosensors or biofuel cells. A poly(histidine) tag had been introduced on the C terminus of a lactate dehydrogenase enzyme. This mutant enzyme was then immobilised onto poly(aniline) (PANi)-poly(anion) composite films, PANi-poly(vinylsulfonate) (PVS) or PANi-poly(acrylate) (PAA). The NADH produced by the immobilised enzyme in the presence of beta-nicotinamide adenine dinucleotide (NAD(+)) and lactate is oxidised at the poly(aniline)-coated electrode at 0.05 to 0.1 V vs. saturated calomel electrode (SCE) at 35 degrees C.

  19. Electrochemical properties of poly(2-chloroaniline)

    Energy Technology Data Exchange (ETDEWEB)

    Fabrizio, M.; Mengoli, G.; Musiani, M.M.; Paolucci, F. (Ist. di Polarografia ed Elettrochimica Preparativa, CNR, Camin (Italy))

    1991-09-01

    The electrochemical behaviour of poly(2-chloroaniline) was studied by cyclic voltammetry and a.c. impedance as a function of the concentration of H{sub 2}SO{sub 4} solutions. In concentrated solutions polymer oxidation occurs as a two-stage process, thus showing the existence of an 'emeraldine' form not detected in {<=}2 M H{sub 2}SO{sub 4} solutions. Both polyaniline and poly(2-chloroaniline) can mediate the oxidation of SO{sub 2}, the performance of the latter polymer being more stable with time. Mediated oxidation of SO{sub 2} occurs within poly(2-chloroaniline) film under kinetic control, so that current is proportional to film thickness. (orig.).

  20. Phenolic Profiling of Duchesnea indica Combining Macroporous Resin Chromatography (MRC with HPLC-ESI-MS/MS and ESI-IT-MS

    Directory of Open Access Journals (Sweden)

    Mingzhi Zhu

    2015-12-01

    Full Text Available Duchesnea indica (D. indica is an important traditional Chinese medicine, and has long been clinically used to treat cancer in Asian countries. It has been described previously as a rich source of phenolic compounds with a broad array of diversified structures, which are the major active ingredients. However, an accurate and complete phenolic profiling has not been determined yet. In the present work, the total phenolic compounds in crude extracts from D. indica were enriched and fractionated over a macroporous resin column, then identified by HPLC-ESI-MS/MS and ESI-IT-MS (ion trap MS. A total of 27 phenolic compounds were identified in D. indica, of which 21 compounds were identified for the first time. These 27 phenolic compounds encompassing four phenolic groups, including ellagitannins, ellagic acid and ellagic acid glycosides, hydroxybenzoic acid and hydroxycinnamic acid derivatives, and flavonols, were then successfully quantified using peak areas against those of the corresponding standards with good linearity (R2 > 0.998 in the range of the tested concentrations. As a result, the contents of individual phenolic compounds varied from 6.69 mg per 100 g dry weight (DW for ellagic acid to 71.36 mg per 100 g DW for brevifolin carboxylate. Not only did this study provide the first phenolic profiling of D. indica, but both the qualitative identification and the subsequent quantitative analysis of 27 phenolic compounds from D. indica should provide a good basis for future exploration of this valuable medicinal plant.

  1. Enrichment of antioxidants from soy sauce using macroporous resin and identification of 4-ethylguaiacol, catechol, daidzein, and 4-ethylphenol as key small molecule antioxidants in soy sauce.

    Science.gov (United States)

    Li, Huipin; Lin, Lianzhu; Feng, Yunzi; Zhao, Mouming; Li, Xiuting; Zhu, Qiyuan; Xiao, Zuobing

    2018-02-01

    The adsorption and desorption characteristics of seven macroporous resins on the antioxidants in soy sauce were investigated. SP-207 and SP-825 resins possessing good adsorption and desorption capacities were studied further. The pseudo-second-order kinetics and Langmuir isotherm models were demonstrated to be appropriate to describe the whole exothermic and physical adsorption processes of antioxidants onto resins. The 60% ethanol eluted fraction from soy sauce purified by SP-825 resin column possessed the strongest antioxidant activity. The antioxidant activities and contents of typical soy isoflavones, furanones, pyranones, and phenolic acids in soy sauce were determined. These compounds contributed to 50.02% of the total antioxidant activity of the SP-60% fraction. The key small molecule antioxidant compounds in soy sauce were identified as 4-ethylguaiacol, catechol, daidzein, and 4-ethylphenol by the antioxidants omission experiments. Additionally, the purified active fraction with high contents of antioxidants from soy sauce could be applied as bioactive ingredient in food industry. Copyright © 2017 Elsevier Ltd. All rights reserved.

  2. Creating 3D Hierarchical Carbon Architectures with Micro-, Meso-, and Macropores via a Simple Self-Blowing Strategy for a Flow-through Deionization Capacitor.

    Science.gov (United States)

    Zhao, Shanshan; Yan, Tingting; Wang, Hui; Zhang, Jianping; Shi, Liyi; Zhang, Dengsong

    2016-07-20

    In this work, 3D hierarchical carbon architectures (3DHCAs) with micro-, meso-, and macropores were prepared via a simple self-blowing strategy as highly efficient electrodes for a flow-through deionization capacitor (FTDC). The obtained 3DHCAs have a hierarchically porous structure, large accessible specific surface area (2061 m(2) g(-1)), and good wettability. The electrochemical tests show that the 3DHCA electrode has a high specific capacitance and good electric conductivity. The deionization experiments demonstrate that the 3DHCA electrodes possess a high deionization capacity of 17.83 mg g(-1) in a 500 mg L(-1) NaCl solution at 1.2 V. Moreover, the 3DHCA electrodes present a fast deionization rate in 100-500 mg L(-1) NaCl solutions at 0.8-1.4 V. The 3DHCA electrodes also present a good regeneration behavior in the reiterative regeneration test. These above factors render the 3DHCAs a promising FTDC electrode material.

  3. Synthesis and Characterization of β-Cyclodextrin Functionalized Ionic Liquid Polymer as a Macroporous Material for the Removal of Phenols and As(V

    Directory of Open Access Journals (Sweden)

    Muggundha Raoov

    2013-12-01

    Full Text Available β-Cyclodextrin-ionic liquid polymer (CD-ILP was first synthesized by functionalized β-cyclodextrin (CD with 1-benzylimidazole (BIM to form monofunctionalized CD (βCD-BIMOTs and was further polymerized using a toluene diisocyanate (TDI linker to form insoluble CD-ILP (βCD-BIMOTs-TDI. The βCD-BIMOTs-TDI polymer was characterized using various tools and the results obtained were compared with those derived from the native β-cyclodextrin polymer (βCD-TDI. The SEM result shows that the presence of ionic liquid (IL increases the pore size, while the thermo gravimetric analysis (TGA result shows that the presence of IL increases the stability of the polymer. Meanwhile, Brunauer-Emmett-Teller (BET results show that βCD-BIMOTs-TDI polymer has 1.254 m2/g surface areas and the Barret-Joyner-Halenda (BJH pore size distribution result reveals that the polymer exhibits macropores with a pore size of 77.66 nm. Preliminary sorption experiments were carried out and the βCD-BIMOTs-TDI polymer shows enhanced sorption capacity and high removal towards phenols and As(V.

  4. Preliminary extraction of tannins by 1-butyl-3-methylimidazole bromide and its subsequent removal from Galla chinensis extract using macroporous resins.

    Science.gov (United States)

    Lu, Chunxia; Luo, Xiaoling; Lu, Liliang; Li, Hongmin; Chen, Xia; Ji, Yong

    2013-03-01

    In recent years, ionic liquids have become increasingly attractive as 'green solvents' used in the extraction of bioactive compounds from natural plant. However, the separation of ionic liquid from the target compounds was difficult, due to their low vapour pressure and high stabilities. In our study, ionic liquid-based ultrasonic and microwave-assisted extraction was used to obtain the crude tannins, then the macroporous resin adsorption technology was further employed to purify the tannins and remove the ionic liquid from crude extract. The results showed that XDA-6 had higher separation efficiency than other tested resins, and the equilibrium experimental data were well fitted to Langmuir isotherms. Dynamic adsorption and desorption were performed on XDA-6 packed in glass columns to optimise the separation process. The optimum conditions as follows: the ratio of column height to diameter bed was 1:8, flow rate 1 BV/h (bed volume per hour), 85% ethanol was used as eluant while the elution volume was 2 BV. Under the optimised conditions, the adsorption and desoption rate of tannins in XDA-6 were 94.81 and 91.63%, respectively. The content of tannins was increased from 70.24% in Galla chinensis extract to 85.12% with a recovery of 99.06%. The result of ultra-performance liquid chromatography (UPLC)-MS/MS analysis showed that [bmim]Br could be removed from extract. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Interconnectivity of macroporous molecularly imprinted polymers fabricated by hydroxyapatite-stabilized Pickering high internal phase emulsions-hydrogels for the selective recognition of protein.

    Science.gov (United States)

    Sun, Yanhua; Li, Yuqing; Xu, Jiangfeng; Huang, Ling; Qiu, Tianyun; Zhong, Shian

    2017-07-01

    Hydroxyapatite hybridized molecularly imprinted polydopamine polymers with selective recognition of bovine hemoglobin (BHb) were successfully prepared via Pickering oil-in-water high internal phase emulsions-hydrogels and molecularly imprinting technique. The emulsions were stabilized by hydroxyapatite of which the wettability was modified by 3-methacryloxypropyltrimethoxysilane. The materials were characterized by SEM, IR and TGA. The results showed that the BHb imprinted polymers based on Pickering hydrogels (Hydro-MIPs) possess macropores ranging from 20μm to 50μm, and their large numbers of amino groups and hydroxyl groups result in a favorable adsorption capacity for BHb. The maximum adsorption capacity of Hydro-MIPs for BHb was 438mg/g, 3.27 times more than that of the non-imprinted polymers (Hydro-NIPs). The results indicated that Hydro-MIPs possessing well-defined hierarchical porous structures exhibited outstanding recognition behavior towards the target protein molecules. This work provided a promising alternative method for the fabrication of polymer materials with tunable and interconnected pores structures for the separation and purification of protein in vitro. Copyright © 2017. Published by Elsevier B.V.

  6. 3D macroporous electrode and high-performance in lithium-ion batteries using SnO2 coated on Cu foam

    Science.gov (United States)

    Um, Ji Hyun; Choi, Myounggeun; Park, Hyeji; Cho, Yong-Hun; Dunand, David C.; Choe, Heeman; Sung, Yung-Eun

    2016-01-01

    A three-dimensional porous architecture makes an attractive electrode structure, as it has an intrinsic structural integrity and an ability to buffer stress in lithium-ion batteries caused by the large volume changes in high-capacity anode materials during cycling. Here we report the first demonstration of a SnO2-coated macroporous Cu foam anode by employing a facile and scalable combination of directional freeze-casting and sol-gel coating processes. The three-dimensional interconnected anode is composed of aligned microscale channels separated by SnO2-coated Cu walls and much finer micrometer pores, adding to surface area and providing space for volume expansion of SnO2 coating layer. With this anode, we achieve a high reversible capacity of 750 mAh g−1 at current rate of 0.5 C after 50 cycles and an excellent rate capability of 590 mAh g−1 at 2 C, which is close to the best performance of Sn-based nanoscale material so far. PMID:26725652

  7. Isolation and purification of six iridoid glycosides from gardenia jasminoides fruit by medium-pressure liquid chromatography combined with macroporous resin chromatography.

    Science.gov (United States)

    Wang, Yun; Liu, Hui; Shen, Lifeng; Yao, Lan; Ma, Yinlian; Yu, Dingrong; Chen, Jianhong; Li, Puling; Chen, Ying; Zhang, Cun

    2015-12-01

    Gardeniae fructus is one of the most frequently used herbs in traditional Chinese medicine. In the present study, a process for the enrichment of six iridoid glycosides from Gardeniae fructus was developed using medium-pressure liquid chromatography combined with macroporous resin and reversed-phase chromatography. The purities of different fractions from Gardeniae fructus were assessed using quantitative high-performance liquid chromatography. After fractionation using HPD-100 column chromatography, a 30% ethanol fraction was selected based on high-performance liquid chromatography and liquid chromatography with mass spectrometry qualitative analysis to separate and purify. Based on the orientation analysis results, six compounds-deacetyl asperulosidic acid methyl ester, gardenoside, ixoroside, scandoside methyl ester, genipin-1-O-β-d-gentiobioside, and geniposide-were successfully isolated and purified in three to four combined steps from Gardeniae fructus. The purities of these compounds were found by high-performance liquid chromatography analysis to be 97.9, 98.1, 95.5, 96.3, 97.1, and 98.7%, respectively. Moreover, their structures were elucidated by NMR spectroscopy and liquid chromatography with tandem mass spectrometry. The separation process was highly efficient, rapid, and accurate, making it a potential approach for the large-scale production of iridoids in the laboratory and providing several marker compounds for quality control. This procedure may be meaningful for the purification of other natural products used in traditional Chinese medicine. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Two solid-phase recycling method for basic ionic liquid [C4mim]Ac by macroporous resin and ion exchange resin from Schisandra chinensis fruits extract.

    Science.gov (United States)

    Ma, Chun-hui; Zu, Yuan-gang; Yang, Lei; Li, Jian

    2015-01-22

    In this study, two solid-phase recycling method for basic ionic liquid (IL) 1-butyl-3-methylimidazolium acetate ([C4mim]Ac) were studied through a digestion extraction system of extracting biphenyl cyclooctene lignans from Schisandra chinensis. The RP-HPLC detection method for [C4mim]Ac was established in order to investigate the recovery efficiency of IL. The recycling method of [C4mim]Ac is divided into two steps, the first step was the separation of lignans from the IL solution containing HPD 5000 macroporous resin, the recovery efficiency and purity of [C4mim]Ac achieved were 97.8% and 67.7%, respectively. This method cannot only separate the lignans from [C4mim]Ac solution, also improve the purity of lignans, the absorption rate of lignans in [C4mim]Ac solution was found to be higher (69.2%) than that in ethanol solution (57.7%). The second step was the purification of [C4mim]Ac by the SK1B strong acid ion exchange resin, an [C4mim]Ac recovery efficiency of 55.9% and the purity higher than 90% were achieved. Additionally, [C4mim]Ac as solvent extraction of lignans from S. chinensis was optimized, the hydrolysis temperature was 90°C and the hydrolysis time was 2h. Copyright © 2014 Elsevier B.V. All rights reserved.

  9. Immobilization of horseradish peroxidase on ZnO nanowires/macroporous SiO2 composites for the complete decolorization of anthraquinone dyes.

    Science.gov (United States)

    Sun, Huaiyan; Jin, Xinyu; Jiang, Feng; Zhang, Ruifeng

    2018-03-01

    A zinc oxide (ZnO) nanowires/macroporous silicon dioxide composite was used as support to immobilize horseradish peroxidase (HRP) simply by in situ cross-linking method. As cross-linker was adsorbed on the surface of ZnO nanowires, the cross-linked HRP was quite different from the traditional cross-linking enzyme aggregates on both structure and catalytic performance. Among three epoxy compounds, diethylene glycol diglycidyl ether (DDE) was the best cross-linker, with which the loading amount of HRP with pI of 5.3 reached as high as 118.1 mg/g and specific activity was up to 14.9 U/mg-support. The mass loss of HRP cross-linked with DDE was negligible during 50-H leaching at 4 °C, and the thermal stability of the immobilized HRP was also quite good. The catalytic performance of immobilized HRP to decolorize anthraquinone dye was explored by using Reactive Blue 19 (RB 19) and Acid Violet 109 (AV 109) as model substrates. The results indicated that the immobilized HRP exhibited high decolorization efficiency and good reusability. The decolorization efficiency reached 94.3% and 95.9% for AV 109 and RB 19 within the first 30 Min, respectively. A complete decolorization of these two dyes has been realized within 2-3 H by using this new biocatalysis system. © 2017 International Union of Biochemistry and Molecular Biology, Inc.

  10. Effect of pore size of three-dimensionally ordered macroporous chitosan-silica matrix on solubility, drug release, and oral bioavailability of loaded-nimodipine.

    Science.gov (United States)

    Gao, Yikun; Xie, Yuling; Sun, Hongrui; Zhao, Qinfu; Zheng, Xin; Wang, Siling; Jiang, Tongying

    2016-01-01

    To explore the effect of the pore size of three-dimensionally ordered macroporous chitosan-silica (3D-CS) matrix on the solubility, drug release, and oral bioavailability of the loaded drug. 3D-CS matrices with pore sizes of 180 nm, 470 nm, and 930 nm were prepared. Nimodipine (NMDP) was used as the drug model. The morphology, specific surface area, and chitosan mass ratio of the 3D-CS matrices were characterized before the effect of the pore size on drug crystallinity, solubility, release, and in vivo pharmacokinetics were investigated. With the pore size of 3D-CS matrix decreasing, the drug crystallinity decreased and the aqueous solubility increased. The drug release was synthetically controlled by the pore size and chitosan content of 3D-CS matrix in a pH 6.8 medium, while in a pH 1.2 medium the erosion of the 3D-CS matrix played an important role in the decreased drug release rate. The area under the curve of the drug-loaded 3D-CS matrices with pore sizes of 930 nm, 470 nm, and 180 nm was 7.46-fold, 5.85-fold, and 3.75-fold larger than that of raw NMDP respectively. Our findings suggest that the oral bioavailability decreased with a decrease in the pore size of the matrix.

  11. Facile preparation of efficient electrocatalysts for oxygen reduction reaction: One-dimensional meso/macroporous cobalt and nitrogen Co-doped carbon nanofibers

    Science.gov (United States)

    Yoon, Ki Ro; Choi, Jinho; Cho, Su-Ho; Jung, Ji-Won; Kim, Chanhoon; Cheong, Jun Young; Kim, Il-Doo

    2018-03-01

    Efficient electrocatalyst for oxygen reduction reaction (ORR) is an essential component for stable operation of various sustainable energy conversion and storage systems such as fuel cells and metal-air batteries. Herein, we report a facile preparation of meso/macroporous Co and N co-doped carbon nanofibers (Co-Nx@CNFs) as a high performance and cost-effective electrocatalyst toward ORR. Co-Nx@CNFs are simply obtained from electrospinning of Co precursor and bicomponent polymers (PVP/PAN) followed by temperature controlled carbonization and further activation step. The prepared Co-Nx@CNF catalyst carbonized at 700 °C (Co-Nx@CNF700) shows outstanding ORR performance, i.e., a low onset potential (0.941 V) and half wave potential (0.814 V) with almost four-electron transfer pathways (n= 3.9). In addition, Co-Nx@CNF700 exhibits a superior methanol tolerance and higher stability (>70 h) in Zn-air battery in comparison with Pt/C catalyst (∼30 h). The outstanding performance of Co-Nx@CNF700 catalysts is attributed to i) enlarged surface area with bimodal porosity achieved by leaching of inactive species, ii) increase of exposed ORR active Co-Nx moieties and graphitic edge sites, and iii) enhanced electrical conductivity and corrosion resistance due to the existence of numerous graphitic flakes in carbon matrix.

  12. Biocompatibility of poly allylamine synthesized by plasma

    International Nuclear Information System (INIS)

    Colin, E.; Enriquez, M.A.; Olayo, M.G.; Cruz, G.J.; Morales, J.; Olayo, R.

    2007-01-01

    A study of the electric and hydrophilic properties of poly allylamine (PAI) synthesized by plasma whose structure contains N-H, C-H, C-O and O-H bonds is presented, that promote the biocompatibility with the human body. To study the PAI hydrolytic affinity, solutions of salt concentration similar to those of the human body were used. The results indicate that the solutions modify the charge balance in the surfaces reducing the hydrophobicity in the poly allylamine whose contact angle oscillates among 10 and 16 degrees and the liquid-solid surface tension between 4 and 8 dina/cm. (Author)

  13. Measurement capability overview in PolyNano

    DEFF Research Database (Denmark)

    Calaon, Matteo; Tosello, Guido; Hansen, Hans Nørgaard

    2012-01-01

    A measurement capability overview has been conducted to evaluate, among the most used instruments in the field of nanometrology, where the PolyNano project should focus its research. The deliverable presents the most relevant instruments to achieve the best possible measurements accuracy matching...... requirements such as low uncertainty, high repeatability and resolution, adequate measuring range and availability among the different project partners. Based on the present measurement capability overview and in relation to the objective of PolyNano to “remove the technology barrier between lab‐scale proof...

  14. Water soluble poly(styrene sulfonate)-b-poly(vinylidene fluoride)-b-poly(styrene sulfonate) triblock copolymer nanoparticles

    Czech Academy of Sciences Publication Activity Database

    Černoch, Peter; Černochová, Zulfiya; Petrova, Svetlana; Kaňková, Dana; Kim, J.-S.; Vasu, V.; Asandei, A. D.

    2016-01-01

    Roč. 6, č. 60 (2016), s. 55374-55381 ISSN 2046-2069 R&D Projects: GA MŠk(CZ) LH14038 Institutional support: RVO:61389013 Keywords : polystyrenesulfonate * poly(neopentyl styrenesulfonate) * PVDF Subject RIV: CD - Macromolecular Chemistry Impact factor: 3.108, year: 2016

  15. Undoped poly (phenyl sulfone) for radiation detection

    International Nuclear Information System (INIS)

    Nakamura, Hidehito; Shirakawa, Yoshiyuki; Sato, Nobuhiro; Kitamura, Hisashi; Takahashi, Sentaro

    2015-01-01

    Undoped aromatic ring polymers are potential scintillation materials. Here, we characterise poly (phenyl sulfone) (PPSU) for radiation detection. The amber-coloured transparent resin emits bluish-white fluorescence with 390-nm maximum. It has an excitation maximum of 340 nm, and has a density of 1.29 g/cm 3 . The effective refractive index based on its emission spectrum is 1.75. The light yield is almost equal to that of poly (ethylene terephthalate), which is a transparent resin. These results demonstrate that PPSU can be used as a component substrate in polymer blends for altering optical characteristics. - Highlights: • Poly (phenyl sulfone) (PPSU) has suitable characteristics as a scintillation material. • PPSU is an amber-coloured transparent resin that emits bluish white fluorescence with 390-nm maximum. • The 1.75 effective refractive index over the emission spectrum is relatively high. • The light yield is 0.95 times that of poly (ethylene terephthalate), which is a transparent resin. • PPSU can potentially alter optical characteristics in polymer blends

  16. Chiral poly(ureidophthalimide) foldamers in water

    NARCIS (Netherlands)

    Sinkeldam, R.W.; Houtem, van M.H.C.J.; Pieterse, K.; Vekemans, J.A.J.M.; Meijer, E.W.

    2006-01-01

    Poly(ureidophthalimide)s decorated with hydrophilic side chains, that ensure soly. in aq. media, have been synthesized and characterized by UV/Vis and CD (CD) spectroscopy. Temp. and concn. dependent CD measurements in water have revealed an almost temp. and concentra-ion independent Cotton effect,

  17. Poly(tetramethyleneterephthalate) crosslinked by irradiation

    International Nuclear Information System (INIS)

    Nyberg, D.D.

    1978-01-01

    Crosslinking, e.g., by irradiation, of a polymer comprising poly(tetramethyleneterephthalate) is made possible by the addition of a member selected from the group consisting of triallyl cyanurate and N,N'-m-phenylenedimaleimide. The resulting crosslinked modified polymer may be rendered heat recoverable

  18. Cytotoxicity of poly(p-phenylenediamine)

    Czech Academy of Sciences Publication Activity Database

    Kuceková, Z.; Rejmontová, P.; Humpolíček, P.; Kašpárková, V.; Bober, Patrycja; Sáha, P.; Stejskal, Jaroslav

    2017-01-01

    Roč. 71, č. 2 (2017), s. 367-372 ISSN 0366-6352 R&D Projects: GA ČR(CZ) GA13-00270S Institutional support: RVO:61389013 Keywords : cytotoxicity * poly(p-phenylenediamine) * mouse embryonic fibroblasts Subject RIV: CD - Macromolecular Chemistry OBOR OECD: Polymer science Impact factor: 1.258, year: 2016

  19. Poly(ethyl methacrylate) and poly(2-ethoxyethyl methacrylate) based polymer gel electrolytes

    Czech Academy of Sciences Publication Activity Database

    Reiter, Jakub; Michálek, Jiří; Vondrák, Jiří; Chmelíková, Dana; Přádný, Martin; Mička, Z.

    2006-01-01

    Roč. 158, č. 1 (2006), s. 509-517 ISSN 0378-7753 R&D Projects: GA MŽP(CZ) SN/3/171/05; GA MŠk(CZ) LC523; GA ČR GA104/02/0731 Institutional research plan: CEZ:AV0Z40320502; CEZ:AV0Z40500505 Keywords : poly mer electrolyte * cross-linked poly mer * lithium batteries Subject RIV: CA - Inorganic Chemistry Impact factor: 3.521, year: 2006

  20. Polyelectrolyte Complex Nanoparticles of Poly(ethyleneimine) and Poly(acrylic acid): Preparation and Applications

    OpenAIRE

    Martin Müller; Bernd Keßler; Sebastian Poeschla; Bernhard Torger; Johanna Fröhlich

    2011-01-01

    In this contribution we outline polyelectrolyte (PEL) complex (PEC) nanoparticles, prepared by mixing solutions of the low cost PEL components poly(ethyleneimine) (PEI) and poly(acrylic acid) (PAC). It was found, that the size and internal structure of PEI/PAC particles can be regulated by process, media and structural parameters. Especially, mixing order, mixing ratio, PEL concentration, pH and molecular weight, were found to be sensible parameters to regulate the size (diameter) of spherica...

  1. Chemical modification of biodegradable polymer poly(3-hydroxybutyrate) by poly(ethylene oxide)

    International Nuclear Information System (INIS)

    Almeida, Lilian L.; Rocha, Gisele A.; Hui, Wang S.

    2009-01-01

    Catalyzed transesterification in the melt was used to produce triblock copolymers from poly(3-hydroxybutyrate) (PHB) and poly(ethyleneoxide) (PEG), in a simplified process. PHB of high molecular weight was depolymerized by pyrolysis and transesterification with dihydroxy terminated PEG occurred through consecutive and partly simultaneous reactions. The effectiveness of the process was verified by the characterization of the formed copolymers by Hydrogen and Carbon-13 Nuclear Magnetic Resonance Spectroscopies (NMR) and solubility analysis in a series of solvents. (author)

  2. Phase Separation and Elastic Properties of Poly(Trimethylene Terephthalate)-block-poly(Ethylene Oxide) Copolymers

    OpenAIRE

    Elżbieta Piesowicz; Sandra Paszkiewicz; Anna Szymczyk

    2016-01-01

    A series of poly(trimethylene terephthalate)-block-poly(ethylene oxide) (PTT-b-PEOT) copolymers with different compositions of rigid PTT and flexible PEOT segments were synthesized via condensation in the melt. The influence of the block length and the block ratio on the micro-separated phase structure and elastic properties of the synthesized multiblock copolymers was studied. The PEOT segments in these copolymers were kept constant at 1130, 2130 or 3130 g/mol, whereas the PTT content varied...

  3. MECHANICAL PROPERTIES OF BLENDS OF PAMAM DENDRIMERS WITH POLY(VINYL CHLORIDE) AND POLY(VINYL ACETATE)

    Science.gov (United States)

    Hybrid blends of poly(amidoamine) PAMAM dendrimers with two linear high polymers, poly(vinyl chloride), PVC, and poly(vinyl acetate), PVAc, are reported. The interaction between the blend components was studied using dynamic mechanical analysis, xenon nuclear magnetic resonacne ...

  4. Effect of Compatibilization on Poly-ε-Caprolactone Grafting onto Poly(ethylene-co-vinyl alcohol

    Directory of Open Access Journals (Sweden)

    Mohamed Taha

    2011-10-01

    Full Text Available The non-miscibility of the reactants during solvent free poly-ε-caprolactone grafting onto poly(ethylene-co-vinyl alcohol (EVOH dramatically affects reaction kinetics. Different solutions were proposed to accelerate the exchange reactions between poly(ethylene-co-vinyl alcohol and poly-ε-caprolactone. Reactions were conducted in a batch reactor or a mini twin-screw extruder. The addition of a poly(ethylene-co-vinyl alcohol-g-poly-ε-caprolactone copolymer increased the compatibility of the reactants and led to a higher reaction rate. This copolymer was either prepared separately and added at the reaction beginning or prepared in situ grafting caprolactone from EVOH. The reactive system evolution was analyzed using molar mass evolution, microstructure characterization, thermal properties and the reactive blend morphology. The compatibilization effect combined with optimized reaction conditions, such as concentration and nature of catalyst and temperature, resulted in an important increase in reaction rates. Among the tested catalysts, 1,5,7-Triazabicyclo [4.4.0]dec-5-ene was a more efficient catalyst for grafting reactions than Tin (II 2-ethylhexanoate.

  5. Aligned poly(L-lactic-co-e-caprolactone) electrospun microfibers and knitted structure: a novel composite scaffold for ligament tissue engineering.

    Science.gov (United States)

    Vaquette, Cédryck; Kahn, Cyril; Frochot, Céline; Nouvel, Cécile; Six, Jean-Luc; De Isla, Natalia; Luo, Li-Hua; Cooper-White, Justin; Rahouadj, Rachid; Wang, Xiong

    2010-09-15

    We developed a novel technique involving knitting and electrospinning to fabricate a composite scaffold for ligament tissue engineering. Knitted structures were coated with poly(L-lactic-co-e-caprolactone) (PLCL) and then placed onto a rotating cylinder and a PLCL solution was electrospun onto the structure. Highly aligned 2-microm-diameter microfibers covered the space between the stitches and adhered to the knitted scaffolds. The stress-strain tensile curves exhibited an initial toe region similar to the tensile behavior of ligaments. Composite scaffolds had an elastic modulus (150 +/- 14 MPa) similar to the modulus of human ligaments. Biological evaluation showed that cells proliferated on the composite scaffolds and they spontaneously orientated along the direction of microfiber alignment. The microfiber architecture also induced a high level of extracellular matrix secretion, which was characterized by immunostaining. We found that cells produced collagen type I and type III, two main components found in ligaments. After 14 days of culture, collagen type III started to form a fibrous network. We fabricated a composite scaffold having the mechanical properties of the knitted structure and the morphological properties of the aligned microfibers. It is difficult to seed a highly macroporous structure with cells, however the technique we developed enabled an easy cell seeding due to presence of the microfiber layer. Therefore, these scaffolds presented attractive properties for a future use in bioreactors for ligament tissue engineering. (c) 2010 Wiley Periodicals, Inc.

  6. Preparation and performance of a novel gel polymer electrolyte based on poly(vinylidene fluoride)/graphene separator for lithium ion battery

    International Nuclear Information System (INIS)

    Liu, Jiuqing; Wu, Xiufeng; He, Junying; Li, Jie; Lai, Yanqing

    2017-01-01

    Poly(vinylidenefluoride)/graphene (PVDF/graphene) gel polymer electrolyte is prepared via non-solvent induced phase separation (NIPS) technique for lithium ion battery application. The effect of graphene on the ion conductivity is investigated by AC impedance measurement. The relationship among the chemical structure, PVDF crystallinity, the graphene on macroporous formation and the ion conductivity are investigated. The results indicate that the graphene disperses homogenously in PVDF, and it also increases the porosity and decreases the crystallinity of the PVDF. At the same time, the unique structure increases the liquid uptake capability of PVDF/graphene polymer electrolyte. The ionic conductivity of the PVDF/graphene polymer electrolyte increases significantly from 1.85 mS cm"−"1 in pristine PVDF to 3.61 mS cm"−"1 with 0.002 wt% graphene. It is found that graphene not only increases the ionic conductivity but also markedly enhances the rate capability and the cycling performances of coin cell. This study shows that PVDF/graphene gel polymer electrolyte is a very promising material for lithium ion batteries.

  7. Thermoresponsive behaviour of terpolymers containing poly(ethylene oxide), poly(2-ethyl-2-oxazoline) and poly(.epsilon.-caprolactone) blocks in aqueous solutions: an NMR study

    Czech Academy of Sciences Publication Activity Database

    Konefal, Rafal; Spěváček, Jiří; Jäger, Eliezer; Petrova, Svetlana

    2016-01-01

    Roč. 294, č. 11 (2016), s. 1717-1726 ISSN 0303-402X R&D Projects: GA ČR(CZ) GA15-13853S; GA MŠk(CZ) 7F14009 Institutional support: RVO:61389013 Keywords : thermoresponsive polymer * terpolymer containing poly(ethylene oxide), poly(2-ethyl-2-oxazoline) and poly(epsilon-caprolactone) blocks * nanoparticles Subject RIV: CD - Macromolecular Chemistry Impact factor: 1.723, year: 2016

  8. Open-chain poly(organophosphazenes). Synthesis and properties

    International Nuclear Information System (INIS)

    Vinogradova, Svetlana V; Tur, Dzidra R; Vasnev, Valery A

    1998-01-01

    Various methods for the synthesis of open-chain poly(organophosphazenes) are considered. The mechanism of polymerisation of hexachlorocyclotriphosphazene and the basic principles of formation of poly(organophosphazene) macromolecules by polymeranalogous reactions of poly(dichloro-phosphazene) with various nucleophilic reagents are analysed from a new viewpoint. The potential of this synthetic method for targeted design of poly(organophosphazenes) of various structures is shown. The possibility of synthesising poly(organophosphazenes) by polymerisation of cyclophosphazenes is also discussed. The problem of unit non-uniformity of poly(organophosphazenes) and its influence on the properties of these polymers are considered. The properties of poly(organophosphazenes) are considered in detail and it is shown that these polymers possess unusual valuable properties, which provide opportunities for their successful practical application. The bibliography includes 276 references.

  9. On-line coupling of counter-current chromatography and macroporous resin chromatography for continuous isolation of arctiin from the fruit of Arctium lappa L.

    Science.gov (United States)

    Guo, Mengzhe; Liang, Junling; Wu, Shihua

    2010-08-13

    In this work, we have developed a novel hybrid two-dimensional counter-current chromatography and liquid chromatography (2D CCC x LC) system for the continuous purification of arctiin from crude extract of Arctium lappa. The first dimensional CCC column has been designed to fractionalize crude complex extract into pure arctiin effluent using a one-component organic/salt-containing system, and the second dimensional LC column has been packed with macroporous resin for on-line adsorption, desalination and desorption of arctiin which was effluent purified from the first CCC dimension. Thus, the crude arctiin mixture has been purified efficiently and conveniently by on-line CCC x LC in spite of the use of a salt-containing solvent system in CCC separation. As a result, high purity (more than 97%) of arctiin has been isolated by repeated injections both using the ethyl acetate-8% sodium chloride aqueous solution and butanol-1% sodium chloride aqueous solution. By contrast with the traditional CCC processes using multi-component organic/aqueous solvent systems, the present on-line CCC x LC process only used a one-component organic solvent and thus the solvent is easier to recover and regenerate. All of used solvents such as ethyl acetate, n-butanol and NaCl aqueous solution are low toxicity and environment-friendly. Moreover, the lower phase of salt-containing aqueous solution used as mobile phase, only contained minor organic solvent, which will save much organic solvent in continuous separation. In summary, our results indicated that the on-line hybrid 2D CCC x LC system using one-component organic/salt-containing aqueous solution is very promising and powerful tool for high-throughput purification of arctiin from fruits of A. lappa. 2010 Elsevier B.V. All rights reserved.

  10. 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.

  11. Novel resorbable glass-ceramic scaffolds for hard tissue engineering: from the parent phosphate glass to its bone-like macroporous derivatives.

    Science.gov (United States)

    Bretcanu, Oana; Baino, Francesco; Verné, Enrica; Vitale-Brovarone, Chiara

    2014-05-01

    One of the major challenges of hard tissue engineering research focuses on the development of scaffolds that can match the mechanical properties of the host bone and resorb at the same rate as the bone is repaired. The aim of this work was the synthesis and characterization of a resorbable phosphate glass, as well as its application for the fabrication of three dimensional (3-D) scaffolds for bone regeneration. The glass microstructure and behaviour upon heating were analysed by X-ray diffraction, differential scanning calorimetry and hot stage microscopy. The glass solubility was investigated according to relevant ISO standards using distilled water, simulated body fluid (SBF) and Tris-HCl as testing media. The glass underwent progressive dissolution over time in all three media but the formation of a hydroxyapatite-like layer was also observed on the samples soaked in SBF and Tris-HCl, which demonstrated the bioactivity of the material. The glass powder was used to fabricate 3-D macroporous bone-like glass-ceramic scaffolds by adopting polyethylene particles as pore formers: during thermal treatment, the polymer additive was removed and the sintering of glass particles was allowed. The obtained scaffolds exhibited high porosity (87 vol.%) and compressive strength around 1.5 MPa. After soaking for 4 months in SBF, the scaffolds mass loss was 76 wt.% and the pH of the solution did not exceed the 7.55 value, thereby remaining in a physiological range. The produced scaffolds, being resorbable, bioactive, architecturally similar to trabecular bone and exhibiting interesting mechanical properties, can be proposed as promising candidates for bone repair applications.

  12. Characterization of macropore structure of Malan loess in NW China based on 3D pipe models constructed by using computed tomography technology

    Science.gov (United States)

    Li, Yanrong; He, Shengdi; Deng, Xiaohong; Xu, Yongxin

    2018-04-01

    Malan loess is a grayish yellow or brownish yellow, clastic, highly porous and brittle late Quaternary sediment formed by the accumulation of windblown dust. The present-day pore structure of Malan loess is crucial for understanding the loessification process in history, loess strengths and mechanical behavior. This study employed a modern computed tomography (CT) device to scan Malan loess samples, which were obtained from the east part of the Loess Plateau of China. A sophisticated and efficient workflow for processing the CT images and constructing 3D pore models was established by selecting and programming relevant mathematical algorithms in MATLAB, such as the maximum entropy method, medial axis method, and node recognition algorithm. Individual pipes within the Malan loess were identified and constructed by partitioning and recombining links in the 3D pore model. The macropore structure of Malan loess was then depicted using quantitative parameters. The parameters derived from 2D images of CT scanning included equivalent radius, length and aspect ratio of pores, porosity, and pore distribution entropy, whereas those derived from the constructed 3D structure models included porosity, coordination number, node density, pipe radius, length, length density, dip angle, and dip direction. The analysis of these parameters revealed that Malan loess is a strongly anisotropic geomaterial with a dense and complex network of pores and pipes. The pores discovered on horizontal images, perpendicular to the vertical direction, were round and relatively uniform in shape and size and evenly distributed, whereas the pores discovered on vertical images varied in shape and size and were distributed in clusters. The pores showed good connectivity in vertical direction and formed vertically aligned pipes but displayed weak connectivity in horizontal directions. The pipes in vertical direction were thick, long, and straight compared with those in horizontal directions. These

  13. Layer-by-layer assembly of graphene oxide on polypropylene macroporous membranes via click chemistry to improve antibacterial and antifouling performance

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Zhen-Bei, E-mail: 1021453457@qq.com [The Key Laboratory of Functional Molecular Solids, Ministry of Education, Anhui Key Laboratory of Molecular-Based Materials, College of Chemistry and Materials Science, Anhui Normal University, East Beijing Rd. 1, Wuhu, Anhui 241000 (China); Wu, Jing-Jing, E-mail: 957522275@qq.com [The Key Laboratory of Functional Molecular Solids, Ministry of Education, Anhui Key Laboratory of Molecular-Based Materials, College of Chemistry and Materials Science, Anhui Normal University, East Beijing Rd. 1, Wuhu, Anhui 241000 (China); Su, Yu, E-mail: 819388710@qq.com [The Key Laboratory of Functional Molecular Solids, Ministry of Education, Anhui Key Laboratory of Molecular-Based Materials, College of Chemistry and Materials Science, Anhui Normal University, East Beijing Rd. 1, Wuhu, Anhui 241000 (China); Zhou, Jin, E-mail: zhoujin_ah@163.com [Department of Materials and Chemical Engineering, Chizhou University, Muzhi Rd. 199, Chizhou, Anhui 247000 (China); Gao, Yong, E-mail: 154682180@qq.com [School of Chemistry and Environmental Engineering, Jiangsu University of Technology, Changzhou 213001 (China); Yu, Hai-Yin, E-mail: yhy456@mail.ahnu.edu.cn [The Key Laboratory of Functional Molecular Solids, Ministry of Education, Anhui Key Laboratory of Molecular-Based Materials, College of Chemistry and Materials Science, Anhui Normal University, East Beijing Rd. 1, Wuhu, Anhui 241000 (China); Gu, Jia-Shan, E-mail: jiashanG@mail.ahnu.edu.cn [The Key Laboratory of Functional Molecular Solids, Ministry of Education, Anhui Key Laboratory of Molecular-Based Materials, College of Chemistry and Materials Science, Anhui Normal University, East Beijing Rd. 1, Wuhu, Anhui 241000 (China)

    2015-03-30

    Graphical abstract: - Highlights: • Clickable membrane prepared by photo bromination and S{sub N}2 nucleophilic substitution. • Azide graphene oxide prepared by ring-opening reaction. • Alkyne graphene oxide was prepared via esterification reaction. • Layer-by-layer assembly of graphene oxide on membrane by click chemistry. • Antibacterial and antifouling characteristics were enhanced greatly. - Abstract: Polypropylene is an extensively used membrane material; yet, polypropylene membranes exhibit extremely poor resistance to protein fouling. To ameliorate this issue, graphene oxide (GO) nanosheets were used to modify macroporous polypropylene membrane (MPPM) via layer-by-layer assembly technique through click reaction. First, alkyne-terminated GO was prepared through esterification between carboxyl groups in GO and amide groups in propargylamine; azide-terminated GO was synthesized by the ring-opening reaction of epoxy groups in GO with sodium azide. Second, GO was introduced to the membrane by click chemistry. Characterizations of infrared spectra and X-ray photoelectron spectroscopy confirmed the modification. The sharply decreasing of static water contact angle indicated the improvement of the surface hydrophilicity for GO modified membrane. Introducing GO to the membrane results in a dramatic increase of water flux, improvements in the antifouling characteristics and antibacterial property for the membranes. The pure water flux through the 5-layered GO modified membrane is 1.82 times that through the unmodified one. The water flux restores to 43.0% for the unmodified membrane while to 79.8% for the modified membrane. The relative flux reduction decreases by 32.1% due to GO modification. The antibacterial property was also enhanced by two-thirds. These results demonstrate that the antifouling and antibacterial characteristics can be raised by tethering GO to the membrane surface.

  14. Layer-by-layer assembly of graphene oxide on polypropylene macroporous membranes via click chemistry to improve antibacterial and antifouling performance

    International Nuclear Information System (INIS)

    Zhang, Zhen-Bei; Wu, Jing-Jing; Su, Yu; Zhou, Jin; Gao, Yong; Yu, Hai-Yin; Gu, Jia-Shan

    2015-01-01

    Graphical abstract: - Highlights: • Clickable membrane prepared by photo bromination and S N 2 nucleophilic substitution. • Azide graphene oxide prepared by ring-opening reaction. • Alkyne graphene oxide was prepared via esterification reaction. • Layer-by-layer assembly of graphene oxide on membrane by click chemistry. • Antibacterial and antifouling characteristics were enhanced greatly. - Abstract: Polypropylene is an extensively used membrane material; yet, polypropylene membranes exhibit extremely poor resistance to protein fouling. To ameliorate this issue, graphene oxide (GO) nanosheets were used to modify macroporous polypropylene membrane (MPPM) via layer-by-layer assembly technique through click reaction. First, alkyne-terminated GO was prepared through esterification between carboxyl groups in GO and amide groups in propargylamine; azide-terminated GO was synthesized by the ring-opening reaction of epoxy groups in GO with sodium azide. Second, GO was introduced to the membrane by click chemistry. Characterizations of infrared spectra and X-ray photoelectron spectroscopy confirmed the modification. The sharply decreasing of static water contact angle indicated the improvement of the surface hydrophilicity for GO modified membrane. Introducing GO to the membrane results in a dramatic increase of water flux, improvements in the antifouling characteristics and antibacterial property for the membranes. The pure water flux through the 5-layered GO modified membrane is 1.82 times that through the unmodified one. The water flux restores to 43.0% for the unmodified membrane while to 79.8% for the modified membrane. The relative flux reduction decreases by 32.1% due to GO modification. The antibacterial property was also enhanced by two-thirds. These results demonstrate that the antifouling and antibacterial characteristics can be raised by tethering GO to the membrane surface

  15. Evaluation of poly (vinyl alcohol) based cryogel–zinc oxide nanocomposites for possible applications as wound dressing materials

    Energy Technology Data Exchange (ETDEWEB)

    Chaturvedi, Archana [Bose Memorial Research Laboratory, Department of Chemistry, Government Autonomous Science College Jabalpur (India); Bajpai, Anil K., E-mail: akbmrl@yahoo.co.in [Bose Memorial Research Laboratory, Department of Chemistry, Government Autonomous Science College Jabalpur (India); Bajpai, Jaya [Bose Memorial Research Laboratory, Department of Chemistry, Government Autonomous Science College Jabalpur (India); Singh, Sunil K. [Department of Chemistry, Guru Ghasidas University, Bilaspur, CG (India)

    2016-08-01

    In this investigation cryogels composed of poly (vinyl alcohol) (PVA) were prepared by repeated freeze thaw method followed by in situ precipitation of zinc oxide nanoparticles within the cryogel networks. Fourier transformed infrared spectroscopy (FTIR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray diffraction (XRD), Energy dispersive X-ray spectroscopy (EDX) were used to characterize the nanocomposites. The morphologies of native PVA cryogels and PVA cryogel-ZnO nanocomposites were observed by scanning electron microscopy (SEM), transmission electron microscopy (TEM) techniques. The SEM analysis suggested that cryogels show a well-defined porous morphology whereas TEM micrographs revealed the presence of nearly spherical and well separated zinc oxide nanoparticles with diameter < 100 nm. XRD results showed all relevant Bragg's reflections for crystal structure of zinc oxide nanoparticles. Thermo gravimetric-differential thermal analysis (TG-DTA) was conducted to evaluate thermal stability of the nanocomposites. Mechanical properties of nanocomposites were determined in terms of tensile strength and percent elongation. Biocompatible nature was ascertained by anti-haemolytic activity, bovine serum albumin (blood protein) adsorption and in vitro cytotoxicity tests. The prepared nanocomposites were also investigated for swelling and deswelling behaviours. The results revealed that both the swelling and deswelling process depend on the chemical composition of the nanocomposites, number of freeze-thaw cycles, pH and temperature of the swelling medium. The developed biocompatible PVA cryogel-ZnO nanocomposites were also tested for antibacterial activities against both Gram-negative and Gram-positive bacteria. - Highlights: • PVA–zinc oxide nanocomposites have been prepared with no chemical crosslinking. • The nanocomposites are completely biocompatible. • They also show antibacterial property. • The nanocomposites

  16. Poly(organo phosphazene) nanoparticles surface modified with poly(ethylene oxide).

    Science.gov (United States)

    Vandorpe, J; Schacht, E; Stolnik, S; Garnett, M C; Davies, M C; Illum, L; Davis, S S

    1996-10-05

    The use of biodegradable derivatives of poly(organo phosphazenes) for the preparation of nanoparticles and their surface modification with the novel poly(ethylene oxide) derivative of poly(organo phosphazene) has been assessed using a range of in vitro characterization methods. The nanoparticles were produced by the precipitation solvent evaporation method from the derivative co-substituted with phenylalanine and glycine ethyl ester side groups. A reduction in particle size to less than 200 nm was achieved by an increase in pH of the preparation medium. The formation (and colloidal stability) of these nanoparticles seems to be controlled by two opposite effects: attractive hydrophobic interactions between phenylalanine ester groups and electrostatic repulsions arising from the carboxyl groups formed due to (partial) hydrolysis of the ester bond(s) at the high pH of the preparation medium. The poly[(glycine ethyl ester)phosphazene] derivative containing 5000-Da poly(ethylene oxide) as 5% of the side groups was used for the surface modification of nanoparticles. Adsorbed onto the particles, the polymer produced a thick coating layer of approximately 35 nm. The coated nanoparticles exhibited reduced surface negative potential and improved colloidal stability toward electrolyte-induced flocculation, relative to the uncoated system. However, the steric stabilization provided was less effective than that of a Poloxamine 908 coating. This difference in effectiveness of the steric stabilization might indicate that, although both the stabilizing polymers possess a 5000-Da poly(ethylene oxide) moiety, there is a difference in the arrangements of these poly(ethylene oxide) chains at the particle surface. (c) 1996 John Wiley & Sons, Inc.

  17. Poly(vinyl-alcohol)/poly(ethylene-glycol)/poly(ethylene-imine) blend membranes - structure and CO2 facilitated transport

    International Nuclear Information System (INIS)

    Ben Hamouda, S.; Quang, Trong Nguyen; Langevin, D.; Sadok, Roudeslic

    2010-01-01

    Poly(vinyl-alcohol) (PVA)/poly(ethylene-imine) (PEI)/poly(ethylene-glycol) (PEG) blend membranes were prepared by solution casting followed by solvent evaporation. The effects of the blend polymer composition on the membrane structure and CO 2 /N 2 permeation characteristics were investigated. IR spectroscopy evidenced strong hydrogen bonding interactions between amorphous PVA and PEI, and weaker interactions between PVA and PEG. DSC studies showed that PVA crystallization was partially inhibited by the interactions between amorphous PVA and PEI blend, in which PEG separated into nodules. The CO 2 permeability decreased with an increase in CO 2 partial pressure in feed gas, while the N 2 permeability remained constant. This result indicated that only CO 2 was transported by the facilitated transport mechanism. The CO 2 and N 2 permeabilities increased monotonically with the PEI content in the blend membranes, whereas the ideal selectivity of CO 2 to N 2 transport showed a maximum. When CO 2 is humidified, its permeability through the blend membranes is much higher than that of dry CO 2 , but the change in permeability due to the presence of humidity is reversible. (authors)

  18. Poly(Lactic Acid) Based Flexible Films

    OpenAIRE

    Fathilah binti Ali; Jamarosliza Jamaluddin; Arun Kumar Upadhyay

    2014-01-01

    Poly(lactic acid) (PLA) is a biodegradable polymer which has good mechanical properties, however, its brittleness limits its usage especially in packaging materials. Therefore, in this work, PLA based polyurethane films were prepared by synthesizing with different types of isocyanates; methylene diisocyanate (MDI) and hexamethylene diisocyanates (HDI). For this purpose, PLA based polyurethane must have good strength and flexibility. Therefore, polycaprolactone which has b...

  19. Preparation and Properties of Poly (vinylidene fluoride)/poly(dimethylsiloxane) graft (poly(propylene oxide)-block-poly(ethylene oxide)) blend porous separators and corresponding electrolytes

    International Nuclear Information System (INIS)

    Li, Hao; Zhang, Hong; Liang, Zhi-Ying; Chen, Yue-Ming; Zhu, Bao-Ku; Zhu, Li-Ping

    2014-01-01

    Highlights: •This work aims exploring microporous PVDF separators for lithium ion batteries. •Comb structure polymer PDMS-g-(PPO-PEO) was used in PVDF blend separators. •The influence of polyether side chains on interfacial resistance was studied. -- Abstract: This work aims exploring the high performance porous separators that can be activated into gel electrolyte membranes for lithium ion batteries. A comb-like copolymer poly (dimethylsiloxane) graft poly (propylene oxide)-block-poly (ethylene oxide) (PDMS-g-(PPO-PEO)) was synthesized and blended with poly (vinylidene fluoride) (PVDF) to fabricate porous separators via a typical phase inversion process, and then the separators absorbed liquid electrolyte solution and formed into polymer electrolyte membranes. By measuring the composition, morphology and ion conductivity etc, the influence of PDMS-g-(PPO-PEO) on structure and properties of blend separators were discussed. Compared with pure PVDF separator with comparable porous structure, the adoption of PDMS-g-(PPO-PEO) decreased the crystallinity and increased the liquid electrolyte uptake and stability effectively. It was also found that the electrode/electrolyte interfacial resistance could be reduced greatly. The resulting electrolyte membrane using separator with PVDF/PDMS-g-(PPO-PEO) mass ratio in 8/2 exhibited highest ionic conductivity in 4.5 × 10 −3 S/cm at room temperature, while the electrochemical stability was up to 4.7 V (vs. Li/Li + ). Coin cells assembled with such separators also exhibited stable cycle performance and improved rate capabilities, especially when discharge rate higher than 0.5 C

  20. Poly(ethylene glycol) interactions with proteins

    Czech Academy of Sciences Publication Activity Database

    Hašek, Jindřich

    2006-01-01

    Roč. 2, č. 23 (2006), s. 613-618 ISSN 0044-2968. [European Powder Diffraction Conference /9./. Prague, 02.09.2004-05.09.2004] R&D Projects: GA ČR(CZ) GA204/02/0843 Institutional research plan: CEZ:AV0Z40500505 Keywords : poly(ethylene glycol) * PEO * protein-polymer interaction Subject RIV: CD - Macromolecular Chemistry Impact factor: 1.897, year: 2006

  1. Synthesis by plasma of halogenated poly anilines

    International Nuclear Information System (INIS)

    Enriquez, M.A.; Olayo, M.G.; Cruz, G.J.

    2002-01-01

    In this work polymerization by plasma of aniline with iodine and chlorine bonded chemically to the aniline ring were realized. The results of the synthesis and characterizations are compared with those ones obtained starting from the poly aniline synthesis (P An) doped with iodine, where the dopant was aggregated in the moment of the polymerization. The objective is to study the dopant behavior in the synthesis by plasma in function of the properties of these polymers. (Author)

  2. Poly(A)-tag deep sequencing data processing to extract poly(A) sites.

    Science.gov (United States)

    Wu, Xiaohui; Ji, Guoli; Li, Qingshun Quinn

    2015-01-01

    Polyadenylation [poly(A)] is an essential posttranscriptional processing step in the maturation of eukaryotic mRNA. The advent of next-generation sequencing (NGS) technology has offered feasible means to generate large-scale data and new opportunities for intensive study of polyadenylation, particularly deep sequencing of the transcriptome targeting the junction of 3'-UTR and the poly(A) tail of the transcript. To take advantage of this unprecedented amount of data, we present an automated workflow to identify polyadenylation sites by integrating NGS data cleaning, processing, mapping, normalizing, and clustering. In this pipeline, a series of Perl scripts are seamlessly integrated to iteratively map the single- or paired-end sequences to the reference genome. After mapping, the poly(A) tags (PATs) at the same genome coordinate are grouped into one cleavage site, and the internal priming artifacts removed. Then the ambiguous region is introduced to parse the genome annotation for cleavage site clustering. Finally, cleavage sites within a close range of 24 nucleotides and from different samples can be clustered into poly(A) clusters. This procedure could be used to identify thousands of reliable poly(A) clusters from millions of NGS sequences in different tissues or treatments.

  3. In vivo and in vitro degradation of poly(ether ester) block copolymers based on poly(ethylene glycol) and poly(butylene terephthalate

    NARCIS (Netherlands)

    Deschamps, A.A.; van Apeldoorn, Aart A.; Hayen, H.; de Bruijn, Joost Dick; Karst, U.; Grijpma, Dirk W.; Feijen, Jan

    2004-01-01

    Two in vivo degradation studies were performed on segmented poly(ether ester)s based on polyethylene glycol (PEG) and poly(butylene terephthalate) (PBT) (PEOT/PBT). In a first series of experiments, the in vivo degradation of melt-pressed discs of different copolymer compositions were followed up

  4. Block copolymers of poly(l-lactide) and poly(e-caprolactone) or poly(ethylene glycol) prepared by reactive extrusion

    NARCIS (Netherlands)

    Stevels, W.M.; Bernard, A.; van de Witte, P.; van de Witte, P.; Dijkstra, Pieter J.; Feijen, Jan

    1996-01-01

    Blends of poly(L-lactide) (PLLA) and poly(-caprolactone) (PCL) were prepared in a co-rotating twin screw miniextruder (40 rpm, 200°). It was attempted to prepare multiblock copolymers by allowing a controlled number of transesterification reactions. Various cat-alysts (n-Bu3SnOMe, Sn(Oct)2,

  5. Neutron structure analyses and structural disorders of poly(p-phenylenebenzobisoxazole) and poly(p-phenylenebenzobisthiazole)

    International Nuclear Information System (INIS)

    Takahashi, Yasuhiro

    2001-01-01

    Poly(p-phenylenebenzobisoxazole)(PBO) and poly(p-phenylenebenzobisthiazole)(PBZT) are disordered with respect to the molecular heights. The molecular heights of PBO are disordered by 1/2 along the molecular axis, while the molecular heights of PBZT are disordered by 1/2 on the ac-plane and by every 1/5 on the bc-plane. Neutron structure analyses of both polymers were carried out for the c-projected structure in the temperature range 17 - 295K. The molecular structures of both polymers deviate from the planar structure. The crystal structures are less dependent on the temperature than the flexible polymers, polyethylene and poly(vinyl alcohol). (author)

  6. Phase Diagrams of Smart Copolymers Poly(N-isopropylacrylamide) and Poly(sodium acrylate)

    Science.gov (United States)

    Di Lorenzo, Maria Laura; Pyda, Marek

    2014-01-01

    The phase behavior of linear poly(N-isopropylacrylamide) (PNIPA), linear copolymer poly(N-isopropylacrylamide) and poly(sodium acrylate) (PNIPA-SA), and chemically cross-linked PNIPA in water has been determined by temperature modulated differential scanning calorimetry (TM-DSC). Experiments related to linear polymers (PNIPA and PNIPA-SA) indicated nontypical demixing/mixing behavior with a lower critical solution temperature (LCST), which do not correspond to the three classical types of limiting critical behavior. Some similarities and differences are observed in comparison to our literature data using standard TM-DSC for PNIPA/water. Furthermore no influence of composition cross-linked PNIPA/water system on demixing/mixing temperature was observed. PMID:25202728

  7. Phase Diagrams of Smart Copolymers Poly(N-isopropylacrylamide and Poly(sodium acrylate

    Directory of Open Access Journals (Sweden)

    Iwona Zarzyka

    2014-01-01

    Full Text Available The phase behavior of linear poly(N-isopropylacrylamide (PNIPA, linear copolymer poly(N-isopropylacrylamide and poly(sodium acrylate (PNIPA-SA, and chemically cross-linked PNIPA in water has been determined by temperature modulated differential scanning calorimetry (TM-DSC. Experiments related to linear polymers (PNIPA and PNIPA-SA indicated nontypical demixing/mixing behavior with a lower critical solution temperature (LCST, which do not correspond to the three classical types of limiting critical behavior. Some similarities and differences are observed in comparison to our literature data using standard TM-DSC for PNIPA/water. Furthermore no influence of composition cross-linked PNIPA/water system on demixing/mixing temperature was observed.

  8. Synthesis and Application of Aurophilic Poly(Cysteine and Poly(Cysteine-Containing Copolymers

    Directory of Open Access Journals (Sweden)

    David Ulkoski

    2017-10-01

    Full Text Available The redox capacity, as well as the aurophilicity of the terminal thiol side groups, in poly(Cysteine lend a unique characteristic to this poly(amino acid or polypeptide. There are two major application fields for this polymer: (i biomedical applications in drug delivery and surface modification of biomedical devices and (ii as coating for electrodes to enhance their electrochemical sensitivity. The intended application determines the synthetic route for p(Cysteine. Polymers to be used in biomedical applications are typically polymerized from the cysteine N-carboxyanhydride by a ring-opening polymerization, where the thiol group needs to be protected during the polymerization. Advances in this methodology have led to conditions under which the polymerization progresses as living polymerization, which allows for a strict control of the molecular architecture, molecular weight and polydispersity and the formation of block copolymers, which eventually could display polyphilic properties. Poly(Cysteine used as electrode coating is typically polymerized onto the electrode by cyclic voltammetry, which actually produces a continuous, pinhole-free film on the electrode via the formation of covalent bonds between the amino group of Cysteine and the carbon of the electrode. This resulting coating is chemically very different from the well-defined poly(Cysteine obtained by ring-opening polymerizations. Based on the structure of cysteine a significant degree of cross-linking within the coating deposited by cyclic voltammetry can be assumed. This manuscript provides a detailed discussion of the ring-opening polymerization of cysteine, a brief consideration of the role of glutathione, a key cysteine-containing tripeptide, and examples for the utilization of poly(Cysteine and poly(Cysteine-containing copolymers, in both, the biomedical as well as electrochemical realm.

  9. Evaluation of miscibility of poly(epichlorohydrin-co-ethylene oxide) and poly(methylmethacrylate) blends

    International Nuclear Information System (INIS)

    Turchete, Renato; Felisberti, Maria Isabel

    1999-01-01

    The miscibility of blends of poly(methylmethacrylate), (PMMA) and poly(epichlorohydrin-co-ethylene oxide), (ECO) were investigated by differential scanning calorimetry. The ECO was fractionated using two different systems: a solvent-non solvent system and by cooling the solution in tetrahydrofuran in the temperature range from 20 to 0 deg C. The fractions with different composition and molecular weight were used to prepare the blends by casting from solution in tetrahydrofuran. The blends exhibit two glass transitions shifted in relation to the glass transitions of the pure polymers, indicating a partial miscibility. Blends containing copolymer richer in epichlorohydrin segments were more miscible than blends of non-fractionated ECO. (author)

  10. STUDIES ON POLY (ETHYLENE TEREPHTHALATE)- POLY ( TETRAMETHYLENE ETHER ) MULTIBLOCK COPOLYMER.Ⅰ. COM POSITIONAL HOMOGENEITY

    Institute of Scientific and Technical Information of China (English)

    ZHAN Yongjian; YING Qicong; WU Meiyan; QIAN Renyuan

    1991-01-01

    The compositional homogeneity of a poly (ethylene terephthalate )-poly (tetramethylene ether)multiblock copolymer sample with low content of hard segment was examined by GPC, TLC, and solubility method. The copolymer sample was found to have a uniform composition as a function of elution volume over the major portion of sample from GPC method. However within one elution fraction, the copolymer chains, although having the same hydrodynamic volume, may have some difference in composition. Two fractions with different composition were obtained by precipitation in ethanol. Some low molar mass copolymers were also separated by a TLC technique from the copolymer sample.

  11. Gold Nanoparticles Protected with Thiol-Derivatized Amphiphilic Poly(epsilon-caprolactone)-b-poly(acrylic acid)

    DEFF Research Database (Denmark)

    Javakhishvili, Irakli; Hvilsted, Søren

    2009-01-01

    ) of tent-butyl acrylate (tBA) in a controlled fashion by use of NiBr2(PPh3)(2) catalyst to produce Prot-PCL-b-PtBA with narrow polydispersities (1.17-1.39). Subsequent mild deprotection protocols provided HS-PCL-b-PAA. Reduction of a gold salt in the presence of this macroligand under thiol......Amphiphilic poly(epsilon-caprolactone)-b-poly(acrylic acid) (HS-PCL-b-PAA) with a thiol functionality in the PCL terminal has been prepared in a novel synthetic cascade. Initially, living anionic ring-opening polymerization (ROP) of epsilon-caprolactone (epsilon-CL) employing the difunctional...

  12. Polis Used in the Sense of Hinterland or Territory

    DEFF Research Database (Denmark)

    Hansen, Mogens Hermann

    2007-01-01

    I arkaisk og klassiske kilder har Ordet polis i betydningen by i flere tilfælde bebetydningen opland og polis i betydningen stat har i flere tilfælde bibetydningen territorium In archaic and classical sources the word polis in the sense of town sometimes carries the connotation hinterland and in ...... and in the sense of state it carries the the connotation territory   ...

  13. Bleeding evaluation of the stationary phase from a few novel macroporous silica-substrate polymeric materials used for radionuclide partitioning from HLLW in MAREC process

    International Nuclear Information System (INIS)

    Zhang, A.; Wei, Y.; Kumagai, M.

    2005-01-01

    To separate minor actinides from HLLW by extraction chromatography, a few novel silica-based di(2-ethylhexyl)phosphoric acid (HDEHP), 4,4',(5')-di(tert-butylcyclohexano)-18-crown-6 (DtBuCH18C6), octyl(phenyl)-N,N-diisobutylcarbamoylmethylphosphine oxide (CMPO), and N,N,N',N'-tetraoctyl-3-oxapentane-1,5-diamide (TODGA) polymeric adsorption materials (HDEHP/SiO 2 -P, DtBuCH18C6/SiO 2 -P, CMPO/SiO 2 -P, and TODGA/SiO 2 -P) were synthesized by impregnating HDEHP, DtBuCH18C6, CMPO, and TODGA into the pores of porous SiO 2 -P particles, which were the new kind of inorganic/organic composites consisted of macroporous SiO 2 and copolymer. The bleeding behavior of these composites was investigated by examining the effect of contact time and HNO 3 concentration. It was found that in the tested HNO 3 concentration range, a noticeable quantity of DtBuCH18C6, at least 600 ppm, leaked out from DtBuCH18C6/SiO 2 -P because of the protonation of DtBuCH18C6 with hydrogen ion, while the others were lower and basically equivalent to the solubility of HDEHP, CMPO, or TODGA in corresponding acidities solutions. Based on the batch experiment, the bleeding of CMPO/SiO 2 -P and TODGA/SiO 2 -P, the main adsorbents used in MAREC process for HLLW partitioning, was evaluated by column operation in 0.01M HNO 3 and 3M HNO 3 . The quantity of CMPO leaked was ∼48 ppm in 0.01M HNO 3 and ∼37 ppm in 3.0M HNO 3 . The bleeding of TODGA decreased from 23.2 ppm to 7.27 ppm at the initial stage and then basically kept constant. An actual bleeding of TODGA was evaluated by the separation of Sr(II) from a 2.0M HNO 3 solution containing 5.0 x 10 -3 M of 6 typically simulated elements. (author)

  14. Synthesis and application of a macroporous silica-based polymeric octyl(phenyl)-N,N-diisobutylcarbamoylmethylphoshine oxide composite for the chromatographic separation of high level liquid waste

    International Nuclear Information System (INIS)

    Zhang, A.

    2006-01-01

    The Minor Actinides Recovery from HLW by Extraction Chromatography (MAREC) process was used mainly for the separation of minor actinides (MAs) and some specific fission products (FPs) from highly active liquid waste (HLW) by the composite CMPO/SiO 2 -P of the macroporous silica based polymeric octyl(phenyl)-N,N-diisobutylcarbamoylmethylphoshine oxide (CMPO) and others. In this study a cascade of chromatographic separation was performed on a 3.0M HNO 3 solution containing 5.0 x 10 -3 M of 13 elements, at 323 K. The cascade consisted of three columns the first and second ones were packed with CMPO/SiO 2 -P and the third with SiO 2 -P particles. The first column was employed to prepare various eluents containing saturated CMPO. The second column was used for separation into groups. The CMPO of CMPO/SiO2-P was recovered from the effluent by the third column and a CMPO-free effluent containing minor actinides was obtained. The elements contained in the simulated HLW of 3.0M HNO 3 were separated into (1) a non-adsorption group (Sr, Cs, and Ru etc.), (2) a MA-hRE (heavy rare earth)-Mo-Zr group, and (3) a lRE (light rare earth) group by eluting with 3.0M HNO 3 , 0.05M DTPA (diethylenetriaminepentaacetic acid) (pH 2.0) and HNO 3 (pH 3.5), respectively. The resultant MA-hRE-Mo-Zr mixture containing minor actinides was then separated into the groups (1) Pd-Ru, (2) MA-hRE, and (3) Mo-Zr by utilizing 3.0M HNO 3 , distilled water, and 0.05M DTPA (pH 2.0) as eluents. More than 92% of CMPO in the MA-hRE containing effluent was adsorbed by SiO 2 -P particles. The effectivity and technical feasibility of MAREC process were demonstrated. (author)

  15. Development of the chromatographic partitioning of cesium and strontium utilizing two macroporous silica-based calix[4]arene-crown and amide impregnated polymeric composites: PREC partitioning process.

    Science.gov (United States)

    Zhang, Anyun; Kuraoka, Etsushu; Kumagai, Mikio

    2007-07-20

    To partition effectively Cs(I) and Sr(II), two harmful heat emitting nuclides, from a highly active liquid waste by extraction chromatography, two kinds of macroporous silica-based polymeric materials, Calix[4]arene-R14/SiO(2)-P and TODGA/SiO(2)-P, were synthesized. Two chelating agents, 1,3-[(2,4-diethyl-heptylethoxy)oxy]-2,4-crown-6-calix[4]arene (Calix[4]arene-R14), an excellent supramolecular compound having molecular recognition ability for Cs(I), and N,N,N',N'-tetraoctyl-3-oxapentane-1,5-diamide (TODGA) were impregnated and immobilized into the pores of SiO(2)-P particles support by a vacuum sucking technique. The loading and elution of 11 typical simulated fission and non-fission products from 4.0M or 2.0M HNO(3) were performed at 298K. It was found that in the first column packed with the Calix[4]arene-R14/SiO(2)-P, all of the simulated elements were separated effectively into two groups: (1) Na(I), K(I), Sr(II), Fe(III), Ba(II), Ru(III), Pd(II), Zr(IV), and Mo(VI) (noted as Sr-group); (2) Cs(I)-Rb(I) (Cs-group) by eluting with 4.0M HNO(3) and distilled water, respectively. The harmful element Cs(I) flowed into the second group along with Rb(I) because of their close sorption and elution properties towards Calix[4]arene-R14/SiO(2)-P, while Sr(II) showed no sorption and flowed into Sr-containing group. In the second column packed with TODGA/SiO(2)-P, the Sr-group was separated into (1) Ba(II), Ru(III), Na(I), K(I), Fe(III), and Mo(VI) (non-sorption group); (2) Sr(II); (3) Pd(II); and (4) Zr(IV) by eluting with 2.0M HNO(3), 0.01M HNO(3), 0.05M DTPA-pH 2.5, and 0.5M H(2)C(2)O(4), respectively. Sr(II) adsorbed towards TODGA/SiO(2)-P flowed into the second group and showed the excellent separation efficiency from others. Based on the elution behavior of the tested elements, an advanced PREC (Partitioning and Recovery of two heat generators from an acidic HLW (high activity liquid waste) by Extraction Chromatography) process was proposed.

  16. Tailoring of poly (3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) copolymers for bone tissue applications

    Science.gov (United States)

    Liu, Hui

    Considerable scientific and technological progress has been made in formulating biomaterials based on natural and synthetic polymers for ultimate use in bone tissue scaffolding. One class of polymers that has drawn attention in recent years for bone tissue engineering application is the biodegradable polymer poly (3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV). PHBV, a microbial polymer, has gained special importance because of favorable mechanical characteristics, biological properties, highly adaptable structure, non-toxic degradation products, and minimal inflammatory response when used as scaffold. However, the lack of natural cell recognition sites on PHBV has resulted in delayed cell attachment, proliferation, differentiation, and tissue regeneration on the polymer. The primary objective of this research is to modify PHBV so as to improve the biocompatibility of the matrix. An approach was developed to prepare porous and bioactive molecule coated scaffold so as to improve the biocompatibility of PHBV matrix. We investigated the role of porosity, collagen coating, and ozone treatment of poly (3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) scaffold on cell proliferation. Based on biochemical assay, we established that maximum cell proliferation occurs on collagen coated and ozone treated porous PHBV film followed by collagen coated porous PHBV film than on porous PHBV film and the least on nonporous PHBV film. Confocal microscopy in combination with biochemical assay was used to generate 3D map of viable cell proliferation on the bulk PHBV matrix. The cells were cultivated on modified PHBV film in mineralization media containing beta-glycerol phosphate for predetermined time interval and later calcium deposits were stained with alizarin red-S assay. Atomic absorption (AA) technique was used to measure the Ca2+ content of the medium and it was found that the longer the cells were incubated in organic phosphate medium, the greater amount of Ca2+ from the medium

  17. Mn2(CO)10-photomediated synthesis of poly(vinylidene fluoride)-b-poly(styrene sulfonate)

    Czech Academy of Sciences Publication Activity Database

    Černoch, Peter; Petrova, Svetlana; Černochová, Zulfiya; Kim, J. S.; Simpson, C. P.; Asandei, A. D.

    2015-01-01

    Roč. 68, July (2015), s. 460-470 ISSN 0014-3057 R&D Projects: GA MŠk(CZ) LH14038 Institutional support: RVO:61389013 Keywords : polystyrenesulfonate * poly(neopentyl styrenesulfonate) * PVDF Subject RIV: CD - Macromolecular Chemistry Impact factor: 3.485, year: 2015

  18. Functional role of zinc in poly(A) synthesis catalyzed by nuclear poly(A) polymerase

    International Nuclear Information System (INIS)

    Rose, K.M.; Allen, M.S.; Crawford, I.L.; Jacob, S.T.; Pennsylvania State Univ., Hershey; Texas Univ., Dallas; Texas Univ., Dallas

    1978-01-01

    The functional role of transition metals in poly(A) synthesis was elucidated by investigating the effect of the metal chelator o-phenanthroline on purified nuclear poly(A) polymerase. This chelator inhibited the enzyme activity in a manner competitive with respect to the polynucleotide primer concentration. o-phenanthroline was a non-competitive inhibitor with regard to ATP concentration and an 'uncompetitive' inhibitor with regard to dithiothreitor levels. The metal content of the purified enzyme preparations from rat liver and Morris hepatoma 3924A was determined using atomic absorption spectrometry. Of the transition metals measured, only zinc was present in detectable quantities, at levels less than 1 mol/mol of enzyme. Hepatoma enzyme contained 2-3 times as much zinc as the corresponding liver enzyme. Hepatoma poly(A) polymerase was also radioactively labelled in vivo by injection of tumor-bearing animals with 65 Zn. Dialysis experiments with highly purified radiolabelled poly(A) polymerase showed that the enzyme-zinc complex was labile and that a reduction in 65 Zn content correlated with a loss in enzyme activity. (orig./AJ) [de

  19. Lithium ion conductivity of molecularly compatibilized chitosan-poly(aminopropyltriethoxysilane)-poly(ethylene oxide) nanocomposites

    International Nuclear Information System (INIS)

    Fuentes, S.; Retuert, P.J.; Gonzalez, G.

    2007-01-01

    Films of composites of chitosan/poly(aminopropyltriethoxysilane)/poly(ethylene oxide) (CHI/pAPS/PEO) containing a fixed amount of lithium salt are studied. The ternary composition diagram of the composites, reporting information on the mechanic stability, the transparence and the electrical conductivity of the films, shows there is a window in which the molecular compatibility of the components is optimal. In this window, defined by the components ratios CHI/PEO 3:2, pAPS/PEO 2:3 and CHI/PEO 1:2, there is a particular composition Li x (CHI) 1 (PEO) 2 (pAPS) 1.2 for which the conductivity reaches a value of 1.7 x 10 -5 S cm -1 at near room temperature. Considering the balance between the Lewis acid and basic sites available in the component and the observed stoichiometry limits of formed polymer complexes, the conductivity values of these products may be understood by the formation of a layered structure in which the lithium ions, stabilized by the donors, poly(ethylene oxide) and/or poly(aminopropyltriethoxysilane), are intercalated in a chitosan matrix

  20. Crystallization and degradation behaviors of poly(butylene succinate)/poly(Z-L-lysine) composites

    International Nuclear Information System (INIS)

    Tan, Licheng; Hu, Jun; Ye, Suwen; Wei, Junchao; Chen, Yiwang

    2014-01-01

    Highlights: • A new biodegradable poly(butylene succinate) (PBS)/poly(Z-L-lysine) (PZlys) composites were successfully prepared through physical blend. • PZlys may greatly affected the crystallization behaviors of PBS without changing its crystalline structure. • The degradation speed of PBS may be greatly accelerated by introduction of PZlys in PBS matrix. - Abstract: A new type of biodegradable poly(butylene succinate) (PBS)/poly(Z-L-lysine) (PZlys) composites were prepared. The crystallization behaviors were investigated by differential scanning calorimetry (DSC), wide angle X-ray diffraction (WAXD) and polarizing optical microscopy (POM) and the results showed that PZlys can restrict the crystallization of PBS, the crystallization speed of PBS/PZlys were slower than that of PBS, and the crystallization degree of the composites were smaller than that of PBS. However, the WAXD results showed that the incorporation of PZlys did not change the crystalline structure of PBS. The in vitro degradation experiments demonstrated that the degradation speed of the composites were faster than that of PBS. Moreover, the mechanical properties of the composites showed that the composites with a proper composition (for example, 80/20) can keep the mechanical properties of PBS without evident difference, which implied that the composites might be potentially useful as biodegradable materials

  1. Functional role of zinc in poly(A) synthesis catalyzed by nuclear poly(A) polymerase

    Energy Technology Data Exchange (ETDEWEB)

    Rose, K M; Allen, M S; Crawford, I L; Jacob, S T [Pennsylvania State Univ., Hershey (USA). Dept. of Pharmacology; Pennsylvania State Univ., Hershey (USA). Specialized Cancer Research Center; Texas Univ., Dallas (USA). Dept. of Neurology; Texas Univ., Dallas (USA). Dept. of Pharmacology)

    1978-07-01

    The functional role of transition metals in poly(A) synthesis was elucidated by investigating the effect of the metal chelator o-Phenanthroline on purified nuclear poly(A) polymerase. This chelator inhibited the enzyme activity in a manner competitive with respect to the polynucleotide primer concentration. o-phenanthroline was a non-competitive inhibitor with regard to ATP concentration and an 'uncompetitive' inhibitor with regard to dithiothreitor levels. The metal content of the purified enzyme preparations from rat liver and Morris hepatoma 3924A was determined using atomic absorption spectrometry. Of the transition metals measured, only zinc was present in detectable quantities at levels less than 1 mol/mol of enzyme. Hepatoma enzyme contained 2-3 times as much zinc as the corresponding liver enzyme. Hepatoma poly(A) polymerase was also radioactively labelled in vivo by injection of tumor-bearing animals with /sup 65/Zn. Dialysis experiments with highly purified radiolabelled poly(A) polymerase showed that the enzyme-zinc complex was labile and that a reduction in /sup 65/Zn content correlated with a loss in enzyme activity.

  2. Stereocomplexed 8-armed poly(ethylene glycol)-poly(lactide) star block copolymer hydrogels: Gelation mechanism, mechanical properties and degradation behavior

    NARCIS (Netherlands)

    Buwalda, S.J.; Calucci, L.; Forte, C.; Dijkstra, Pieter J.; Feijen, Jan

    2012-01-01

    Mixing aqueous poly(ethylene glycol)-poly(d-lactide) and poly(ethylene glycol)-poly(l-lactide) star block copolymer solutions resulted in the formation of stereocomplexed hydrogels within 1 min. A study towards the mechanism of the temperature dependent formation of stereocomplexes in the hydrogels

  3. Social Media Discovery en PoliBuscador

    OpenAIRE

    Campos Alemany, Anna

    2014-01-01

    Presentación en las XI Jormadas de la Asociación de Usuarios de Ex Libris en España (Expania) celebradas en la Universidad Politécnica de Valencia (UPV) el 4 y 5 de junio de 2014, con un programa centrado en la interoperabilidad y la integración de servicios y datos Esta herramienta nos permite capturar, describir y presentar en forma de listado los numerosos recursos web que complementan y enriquecen los recursos para la docencia, el aprendizaje y la investigación ofrecidos desde PoliBusc...

  4. Preparation of conductive membranes using poly pyrrole

    International Nuclear Information System (INIS)

    Madaeni, S.; Khavaran, B.

    2003-01-01

    Conductive membranes show many benefits including fouling reduction for feeds containing ionic species. These membranes may be prepared either by conductive polymers or coating of the surfaces of non-conductive membranes with conductive polymer. In this research, the commercial micro filtration GVHP membrane manufactured from PVDF was coated with poly pyrrole using two different techniques. The conductivity of the prepared membranes was measured. In this paper, effects of various factors including concentration of the solutions, oxidizing agents, time for leaving the support in the solutions, support type and temperature on membrane conductivity were investigated

  5. Adhesion Between Poly(dimethylsiloxane) Layers

    DEFF Research Database (Denmark)

    Yu, Liyun; Daugaard, Anders Egede; Skov, Anne Ladegaard

    Different adhesion methods of poly(dimethylsiloxane) (PDMS) layers were studied with respect to adhesional force and the resulting rheology of the two-layered PDMS films were investigated. The role of adhesion between PDMS layers on the performances of two-layer structures was studied with peel...... strength test and by SEM pictures. The rheology of the double-layered compared to the monolayer films changed in some cases which indicates that the adhesion process needs to be carefully introduced in order not to alter the final properties....

  6. Association of poly-purine/poly-pyrimidine sequences with meiotic recombination hot spots

    Directory of Open Access Journals (Sweden)

    Pitt Joel PW

    2006-07-01

    Full Text Available Abstract Background Meiotic recombination events have been found to concentrate in 1–2.5 kilo base regions, but these recombination hot spots do not share a consensus sequence and why they occur at specific sites is not fully understood. Some previous evidence suggests that poly-purine/poly-pyrimidine (poly-pu/py tracts (PPTs, a class of sequence with distinctive biochemical properties, could be involved in recombination, but no general association of PPTs with meiotic recombination hot spots has previously been reported. Results We used computational methods to investigate in detail the relationship between PPTs and hot spots. We show statistical associations of PPT frequency with hot spots of meiotic recombination initiating lesions, double-strand breaks, in the genome of the yeast S. cerevisiae and with experimentally well characterized human meiotic recombination hot spots. Supporting a possible role of poly-pu/py-rich sequences in hot spot recombination, we also found that all three single nucleotide polymorphisms previously shown to be associated with human hot spot activity changes occur within sequence contexts of 14 bp or longer that are 85% or more poly-pu/py and at least 70% G/C. These polymorphisms are all close to the hot spot mid points. Comparing the sequences of experimentally characterized human hot spots with the orthologous regions of the chimpanzee genome previously shown not to contain hot spots, we found that in all five cases in which comparisons for the hot spot central regions are possible with publicly available sequence data, there are differences near the human hot spot mid points within sequences 14 bp or longer consisting of more than 80% poly-pu/py and at least 50% G/C. Conclusion Our results, along with previous evidence for the unique biochemical properties and recombination-stimulating potential of poly-pu/py-rich sequences, suggest that the possible functional involvement of this type of sequence in meiotic

  7. Synthesis and characterization of biodegradable poly (ethylene glycol) and poly (caprolactone diol) end capped poly (propylene fumarate) cross linked amphiphilic hydrogel as tissue engineering scaffold material.

    Science.gov (United States)

    Krishna, Lekshmi; Jayabalan, Muthu

    2009-12-01

    Biodegradable poly (caprolactone diol-co-propylene fumarate-co-ethylene glycol) amphiphilic polymer with poly (ethylene glycol) and poly (caprolactone diol) chain ends (PCL-PPF-PEG) was prepared. PCL-PPF-PEG undergoes fast setting with acrylamide (aqueous solution) by free radical polymerization and produces a crosslinked hydrogel. The cross linked and freeze-dried amphiphilic material has porous and interconnected network. It undergoes higher degree of swelling and water absorption to form hydrogel with hydrophilic and hydrophobic domains at the surface and appreciable tensile strength. The present hydrogel is compatible with L929 fibroblast cells. PCL-PPF-PEG/acrylamide hydrogel is a candidate scaffold material for tissue engineering applications.

  8. Curcumin Encapsulated into Methoxy Poly(Ethylene Glycol) Poly(ε-Caprolactone) Nanoparticles Increases Cellular Uptake and Neuroprotective Effect in Glioma Cells.

    Science.gov (United States)

    Marslin, Gregory; Sarmento, Bruno Filipe Carmelino Cardoso; Franklin, Gregory; Martins, José Alberto Ribeiro; Silva, Carlos Jorge Ribeiro; Gomes, Andreia Ferreira Castro; Sárria, Marisa Passos; Coutinho, Olga Maria Fernandes Pereira; Dias, Alberto Carlos Pires

    2017-03-01

    Curcumin is a natural polyphenolic compound isolated from turmeric ( Curcuma longa ) with well-demonstrated neuroprotective and anticancer activities. Although curcumin is safe even at high doses in humans, it exhibits poor bioavailability, mainly due to poor absorption, fast metabolism, and rapid systemic elimination. To overcome these issues, several approaches, such as nanoparticle-mediated targeted delivery, have been undertaken with different degrees of success. The present study was conducted to compare the neuroprotective effect of curcumin encapsulated in poly( ε -caprolactone) and methoxy poly(ethylene glycol) poly( ε -caprolactone) nanoparticles in U251 glioblastoma cells. Prepared nanoparticles were physically characterized by laser doppler anemometry, transmission electron microscopy, and X-ray diffraction. The results from laser doppler anemometry confirmed that the size of poly( ε -caprolactone) and poly(ethylene glycol) poly( ε -caprolactone) nanoparticles ranged between 200-240 nm for poly( ε -caprolactone) nanoparticles and 30-70 nm for poly(ethylene glycol) poly( ε -caprolactone) nanoparticles, and transmission electron microscopy images revealed their spherical shape. Treatment of U251 glioma cells and zebrafish embryos with poly( ε -caprolactone) and poly(ethylene glycol) poly( ε -caprolactone) nanoparticles loaded with curcumin revealed efficient cellular uptake. The cellular uptake of poly(ethylene glycol) poly( ε -caprolactone) nanoparticles was higher in comparison to poly( ε -caprolactone) nanoparticles. Moreover, poly(ethylene glycol) poly( ε -caprolactone) di-block copolymer-loaded curcumin nanoparticles were able to protect the glioma cells against tBHP induced-oxidative damage better than free curcumin. Together, our results show that curcumin-loaded poly(ethylene glycol) poly( ε -caprolactone) di-block copolymer nanoparticles possess significantly stronger neuroprotective effect in U251 human glioma cells compared to

  9. Ferromagnetism in poly(N-perfluorophenylpyrrole)

    Energy Technology Data Exchange (ETDEWEB)

    Čík, G., E-mail: gabriel.cik@stuba.sk [Department of Environmental Engineering, Faculty of Chemical and Food Technology, Slovak University of Technology, 812 37 Bratislava (Slovakia); Šeršeň, F. [Institute of Chemistry, Faculty of Natural Sciences, Comenius University, 842 15 Bratislava (Slovakia); Dlháň, L. [Department of Inorganic Chemistry, Faculty of Chemical and Food Technology, Slovak University of Technology, 812 37 Bratislava (Slovakia); Zálupský, P. [Department of Organic Chemistry, Faculty of Chemical and Food Technology, Slovak University of Technology, 812 37 Bratislava (Slovakia); Rapta, P. [Department of Physical Chemistry, Faculty of Chemical and Food Technology, Slovak University of Technology, 812 37 Bratislava (Slovakia); Hrnčariková, K. [Department of Organic Chemistry, Faculty of Chemical and Food Technology, Slovak University of Technology, 812 37 Bratislava (Slovakia); Plecenik, T. [Department of Experimental Physics, Faculty of Mathematics, Physics and Informatics, Comenius University, 842 48 Bratislava (Slovakia)

    2015-10-01

    Magnetic properties of the synthesized poly(N-perfluorophenylpyrrole) were studied. The synthesized polymer dissolves in common organic solvents. By the zero-field cooling-field cooling method (ZFC–FC) we found that at low temperatures (T{sub b}<50 K) the synthetic polymer reaches a state with prevailing ferromagnetism. The synthesized polymer retained ferromagnetism even at 300 K. The anomalous magnetic behavior was explained in terms of spin–spin interaction of triplet polarons. As can be seen from the calculated spin density of SOMO and SOMO 1 such a state arise as a consequence of 1-D spin interactions of polarons. Based on the calculated and visualized spin density (SOMO) on the polymer chain such interactions can be explained by the theory of flat-band-ferromagnetism. - Highlights: • We synthesized a new conducting polymer poly(N-perfluorophenylpyrrole). • By the ZFC–FC and EPR methods we measured magnetic properties of the prepared polymer. • We discussed stability and interactions of the polarons in triplet states. • At low temperatures the synthesized polymer reached ferromagnetism.

  10. Neutron Transmission of Germanium Poly- and Monocrystals

    International Nuclear Information System (INIS)

    Habib, N.

    2009-01-01

    The measured total neutron cross-sections of germanium poly- and mono-crystals were analyzed using an additive formula. The formula takes into account the germanium crystalline structure and its physical parameters. Computer programs have developed in order to provide the required analyses. The calculated values of the total cross-section of polycrystalline germanium in the neutron wavelength range from 0.001 up to 0.7 nm were fitted to the measured ones at ETRR-1. From the fitting the main constants of the additive formula were determined. The experimental data measured at ETRR-1 of the total cross-section of high quality Ge single crystal at 4400 K, room, and liquid nitrogen temperatures, in the wavelength range between 0.028 nm and 0.64 nm, were also compared with the calculated values using the formula having the same constants. An overall agreement is noticed between the formula fits and experimental data. A feasibility study is done for the use of germanium in poly-crystalline form, as cold neutron filter, and in mono-crystalline one as an efficient filter for thermal neutrons. The filtering efficiency of Ge single crystal is detailed in terms of its isotopic abundance, crystal thickness, mosaic spread, and temperature. It can be concluded that the 7.5 cm thick 76 Ge single crystal (0.10 FWHM mosaic spread) cooled at liquid nitrogen temperature is an efficient thermal neutron filter.

  11. Synthesis of poly(furfuryl alcohol)/montmorillonite nanocomposites ...

    Indian Academy of Sciences (India)

    The purpose of this study was to obtain poly(furfuryl alcohol) nanocomposites with Algerian organically modified clay (termed 12-montmorillonite). The formation of poly(furfuryl alcohol) was confirmed by infrared spectroscopy (IR); the prepared nanocomposites were characterized by X-ray diffraction (XRD), transmission ...

  12. Poly(furfuryl alcohol) nanospheres: a facile synthesis approach ...

    Indian Academy of Sciences (India)

    poly(furfuryl alcohol) (PFA) nanospheres with an average diameter of 350 nm in the presence of poly(vinyl pyrroli- done) (PVP) ... with metal cations and subsequent conversion to metal oxide ... 2.2 Preparation of α-Fe2O3 hollow nanospheres.

  13. Surface grafting of poly(L-glutamates). 3. Block copolymerization

    NARCIS (Netherlands)

    Wieringa, RH; Siesling, EA; Werkman, PJ; Vorenkamp, EJ; Schouten, AJ

    2001-01-01

    This paper describes for the first time the synthesis of surface-grafted AB-block copolypeptides, consisting of poly(gamma -benzyl L-glutamate) (PBLG) as the A-block and poly(gamma -methyl L-glutamate) (PMLG) as the B-block. Immobilized primary amine groups of (,gamma -aminopropyl)triethoxysilane

  14. Multifunctional poly(alkyl methacrylate) films for dental care

    International Nuclear Information System (INIS)

    Nielsen, Birthe V; Nevell, Thomas G; Barbu, Eugen; Smith, James R; Tsibouklis, John; Rees, Gareth D

    2011-01-01

    Towards the evaluation of non-permanent dental coatings for their capacity to impart dental-care benefits, thin films of a homologous series of comb-like poly(alkyl methacrylate)s (ethyl to octadecyl) have been deposited, from aqueous latex formulations, onto dentally relevant substrates. AFM studies have shown that the thickness (40-300 nm) and surface roughness (8-12 nm) of coherent polymer films are influenced by the degree of polymerization and by the length of the pendant chain. Of the polymers under consideration, poly(butyl methacrylate) formed a close-packed film that conferred to dental substrates a high degree of inhibition to acid-mediated erosion (about 27%), as evaluated by released-phosphate determinations. The potential utility of the coatings to act as anti-sensitivity barriers has been evaluated by determining the hydraulic conductance of coated bovine-dentine substrates; single treatments of dentine discs with poly(butyl methacrylate) or with poly(ethyl methacrylate) effected mean respective reductions in fluid flow of about 23% with respect to water-treated controls; repeated applications of the poly(butyl methacrylate) latex led to mean reductions in fluid flow of about 80%. Chromometric measurements have shown that pellicle-coated hydroxyapatite discs treated with poly(butyl methacrylate), poly(hexyl methacrylate) or poly(lauryl methacrylate) exhibit significant resistance to staining by food chromogens.

  15. Poly(ether ester amide)s for tissue engineering

    NARCIS (Netherlands)

    Deschamps, A.A.; van Apeldoorn, Aart A.; de Bruijn, Joost Dick; Grijpma, Dirk W.; Feijen, Jan

    2003-01-01

    Poly(ether ester amide) (PEEA) copolymers based on poly(ethylene glycol) (PEG), 1,4-butanediol and dimethyl-7,12-diaza-6,13-dione-1,18-octadecanedioate were evaluated as scaffold materials for tissue engineering. A PEEA copolymer based on PEG with a molecular weight of 300 g/mol and 25 wt% of soft

  16. Paso del Aguilo : Jarre de type Rio Verde Poli

    OpenAIRE

    Michelet , Dominique

    1981-01-01

    Zone IV, site n°2. Las Colaciones, Paso del Aguila, municipio Armadillo, San Luis Potosi.Jarre à deux petites anses latérales sous le col, du type Rio Verde Poli. Engobe brun-beige poli. Hauteur totale 13 centimètres. Collection particulière Paso del Aguila.

  17. Multifunctional poly(alkyl methacrylate) films for dental care

    Energy Technology Data Exchange (ETDEWEB)

    Nielsen, Birthe V; Nevell, Thomas G; Barbu, Eugen; Smith, James R; Tsibouklis, John [School of Pharmacy and Biomedical Sciences, University of Portsmouth, Portsmouth, Hampshire, PO1 2DT (United Kingdom); Rees, Gareth D [GlaxoSmithKline R and D, St George' s Avenue, Weybridge, Surrey, KT13 0DE (United Kingdom)

    2011-02-15

    Towards the evaluation of non-permanent dental coatings for their capacity to impart dental-care benefits, thin films of a homologous series of comb-like poly(alkyl methacrylate)s (ethyl to octadecyl) have been deposited, from aqueous latex formulations, onto dentally relevant substrates. AFM studies have shown that the thickness (40-300 nm) and surface roughness (8-12 nm) of coherent polymer films are influenced by the degree of polymerization and by the length of the pendant chain. Of the polymers under consideration, poly(butyl methacrylate) formed a close-packed film that conferred to dental substrates a high degree of inhibition to acid-mediated erosion (about 27%), as evaluated by released-phosphate determinations. The potential utility of the coatings to act as anti-sensitivity barriers has been evaluated by determining the hydraulic conductance of coated bovine-dentine substrates; single treatments of dentine discs with poly(butyl methacrylate) or with poly(ethyl methacrylate) effected mean respective reductions in fluid flow of about 23% with respect to water-treated controls; repeated applications of the poly(butyl methacrylate) latex led to mean reductions in fluid flow of about 80%. Chromometric measurements have shown that pellicle-coated hydroxyapatite discs treated with poly(butyl methacrylate), poly(hexyl methacrylate) or poly(lauryl methacrylate) exhibit significant resistance to staining by food chromogens.

  18. Synthesis of Poly(vinyl ether) Thermoplastic Elastomers Having Functional Soft Segments

    OpenAIRE

    今枝, 嗣人; 漆崎, 美智遠; 阪口, 壽一; 橋本, 保; Tsuguto, IMAEDA; Michio, URUSHISAKI; Toshikazu, SAKAGUCHI; Tamotsu, HASHIMOTO

    2013-01-01

    The ABA-type triblock copolymers consisting of poly(2-adarnantyl vinyl ether) [poly(2-AdVE) as outer hard segments and poly(6-acetoxyhexyl vinyl ether) [poly(AcHVE)] poly(6-hydroxyhexyl vinyl ether) [poly(H HVE)], or poly(2-(2-methoxyethoxy)ethyl vinyl ether [poly(MOEOVE)] as inner soft segments were synthesized by sequential living cationic polymerization. Despite the presence of polar functional groups such as ester, hydroxy, and oxyethylene units in their soft segments, the two polymer seg...

  19. Synthesis of polystyrene, poly(styrene/4-vinylpyridine), poly(p-nitrostyrene) and poly(p-aminostyrene)-coated silica and their extraction capabilities for amphetamine

    International Nuclear Information System (INIS)

    Sun Changmei; Zhang Shuanhong; Qu Rongjun; Sun Tao; Zhang Ying; Zhang Xiang; Song Jingyang

    2010-01-01

    Several novel organic-inorganic hybrid materials, including polystyrene-coated silica (SG-PS), poly(styrene/4-vinylpyridine)-coated silica (SG-PVP), poly(p-nitrostyrene)-coated silica (SG-PS-NO 2 ) and poly(p-aminostyrene)-coated silica (SG-PS-NH 2 ), were synthesized in order to improve the extraction methods of harmful stimulants via solid phase extraction. The materials were characterized using infrared spectra (IR), scanning electron microscope (SEM), Brunauer-Emmett-Teller (BET) surface area measurement and thermogravimetric analysis (TG). The application of the new materials in solid phase extraction columns to extract methamphetamine revealed that the extraction capability of poly(styrene/4-vinylpyridine)-coated silica is the best among the four materials, which provides novel supporter materials for extracting amphetamine-derived drugs.

  20. Synthesis of polystyrene, poly(styrene/4-vinylpyridine), poly(p-nitrostyrene) and poly(p-aminostyrene)-coated silica and their extraction capabilities for amphetamine

    Energy Technology Data Exchange (ETDEWEB)

    Sun Changmei; Zhang Shuanhong [School of Chemistry and Materials Science, Ludong University, Yantai, Shandong 264025 (China); Qu Rongjun, E-mail: qurongjun@eyou.com [School of Chemistry and Materials Science, Ludong University, Yantai, Shandong 264025 (China); Sun Tao; Zhang Ying; Zhang Xiang; Song Jingyang [School of Chemistry and Materials Science, Ludong University, Yantai, Shandong 264025 (China)

    2010-11-01

    Several novel organic-inorganic hybrid materials, including polystyrene-coated silica (SG-PS), poly(styrene/4-vinylpyridine)-coated silica (SG-PVP), poly(p-nitrostyrene)-coated silica (SG-PS-NO{sub 2}) and poly(p-aminostyrene)-coated silica (SG-PS-NH{sub 2}), were synthesized in order to improve the extraction methods of harmful stimulants via solid phase extraction. The materials were characterized using infrared spectra (IR), scanning electron microscope (SEM), Brunauer-Emmett-Teller (BET) surface area measurement and thermogravimetric analysis (TG). The application of the new materials in solid phase extraction columns to extract methamphetamine revealed that the extraction capability of poly(styrene/4-vinylpyridine)-coated silica is the best among the four materials, which provides novel supporter materials for extracting amphetamine-derived drugs.

  1. Temperature-induced phase transition in hydrogels of interpenetrating networks poly(N-isopropylmethacrylamide)/poly(N-isopropylacrylamide)

    Czech Academy of Sciences Publication Activity Database

    Šťastná, J.; Hanyková, L.; Sedláková, Zdeňka; Valentová, H.; Spěváček, Jiří

    2013-01-01

    Roč. 291, č. 10 (2013), s. 2409-2417 ISSN 0303-402X R&D Projects: GA ČR GA202/09/1281 Institutional support: RVO:61389013 Keywords : temperature-induced volume phase transition * poly (N-isopropylmethacrylamide) poly (Nisopropylacrylamide) interpenetrating network * 1H NMR spectroscopy Subject RIV: CD - Macromolecular Chemistry Impact factor: 2.410, year: 2013

  2. Large electrically induced height and volume changes in poly(3,4- ethylenedioxythiophene) /poly(styrenesulfonate) thin films

    NARCIS (Netherlands)

    Charrier, D.S.H.; Janssen, R.A.J.; Kemerink, M.

    2010-01-01

    We demonstrate large, partly reversible height and volume changes of thin films of poly(3,4-ethylenedioxythiophene)/poly(styrenesulfonate) (PEDOT:PSS) on the anode of interdigitating gold electrodes under ambient conditions by applying an electrical bias. The height and volume changes were monitored

  3. High molecular weight poly(L-lactide) and poly(ethylene oxide) blends : Thermal characterization and physical properties

    NARCIS (Netherlands)

    Nijenhuis, AJ; Colstee, E; Grijpma, DW; Pennings, AJ

    1996-01-01

    The miscibility of high molecular weight poly(L-lactide) (PLLA) with high molecular weight poly(ethylene oxide) (PEG) was studied by differential scanning calorimetry. Ail blends containing up to 50 weight% PEO showed single glass transition temperatures. The PLLA and PEO melting temperatures were

  4. Bio-derived polymers for coating applications : comparing poly(limonene carbonate) and poly(cyclohexadiene carbonate)

    NARCIS (Netherlands)

    Stößer, T.; Li, C.; Unruangsri, J.; Saini, P.K.; Sablong, R.J.; Meier, M.A.R..; Williams, C.K.; Koning, C.

    2017-01-01

    Two fully bio-based polycarbonates, poly(cyclohexadiene carbonate) (PCHDC) and poly(limonene carbonate) (PLC), are synthesised from carbon dioxide and cyclohexadiene oxide and limonene oxide. The low molecular weight polycarbonates are cross-linked by a photoinitiated reaction with

  5. Pervaporation of alcohol-toluene mixtures through polymer blend membranes of poly(acrylic acid) and poly(vinyl alcohol)

    NARCIS (Netherlands)

    Park, H.C.; Park, H.; Meertens, R.M.; Meertens, R.M.; Mulder, M.H.V.; Smolders, C.A.; Smolders, C.A.

    1994-01-01

    Homogeneous membranes were prepared by blending poly(acrylic acid) with poly(vinyl alcohol). These blend membranes were evaluated for the selective separation of alcohols from toluene by pervaporation. The flux and selectivity of the membranes were determined both as a function of the blend

  6. 21 CFR 177.1635 - Poly(p-methylstyrene) and rubber-modified poly(p-methyl-styrene).

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Poly(p-methylstyrene) and rubber-modified poly(p-methyl-styrene). 177.1635 Section 177.1635 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED) INDIRECT FOOD ADDITIVES: POLYMERS Substances for Use as Basic Components...

  7. Effect of block composition on thermal properties and melt viscosity of poly[2-(dimethylaminoethyl methacrylate], poly(ethylene oxide and poly(propylene oxide block co-polymers

    Directory of Open Access Journals (Sweden)

    2011-09-01

    Full Text Available To modify the rheological properties of certain commercial polymers, a set of block copolymers were synthesized through oxyanionic polymerization of 2-(dimethylaminoethyl methacrylate to the chain ends of commercial prepolymers, namely poly(ethylene oxide (PEO, poly(ethylene oxide-block-poly(propylene oxide-block-poly(ethylene oxide (PEO-PPO-PEO, and poly(propylene oxide (PPO. The formed block copolymers were analysed with size exclusion chromatography and nuclear magnetic resonance spectroscopy in order to confirm block formation. Thermal characterization of the resulting polymers was done with differential scanning calorimetry. Thermal transition points were also confirmed with rotational rheometry, which was primarily used to measure melt strength properties of the resulting block co-polymers. It was observed that the synthesised poly[2-(dimethylaminoethyl methacrylate]-block (PDM affected slightly the thermal transition points of crystalline PEO-block but the influence was stronger on amorphous PPO-blocks. Frequency sweeps measured above the melting temperatures for the materials confirmed that the pre-polymers (PEO and PEO-PPO-PEO behave as Newtonian fluids whereas polymers with a PDM block structure exhibit clear shear thinning behaviour. In addition, the PDM block increased the melt viscosity when compared with that one of the pre-polymer. As a final result, it became obvious that pre-polymers modified with PDM were in entangled form, in the melted state as well in the solidified form.

  8. Electro-oxidation of chlorophenols on poly(3,4-ethylenedioxythiophene)-poly(styrene sulphonate) composite electrode

    International Nuclear Information System (INIS)

    Pigani, L.; Musiani, M.; Pirvu, C.; Terzi, F.; Zanardi, C.; Seeber, R.

    2007-01-01

    The electrochemical behaviour of chlorinated phenols on Pt/poly(3,4-ethylenedioxy)thiophene,LiClO 4 and on Pt/poly(3,4-ethylenedioxy)thiophene,poly(sodium-4-styrenesulphonate) electrodes has been investigated in phosphate buffer solution. Poly(sodium-4-styrenesulphonate) exerts remarkable effect against the electrode fouling induced by oxidation of chlorophenols, allowing us to record the relevant anodic response even after repeated potential cycles. Hypotheses about the role exerted by poly(sodium 4-styrenesulphonate) are made, on the basis of evidences provided by several techniques, such as cyclic voltammetry, electrochemical impedance spectroscopy, electrochemical microgravimetry and atomic force microscopy. Thanks to the fact that different chlorophenols show differences in the voltammetric responses, depending on number and position of the chloro substituents on the aromatic ring, applications of the modified electrode in the analysis of mixtures of chlorinated phenols are possible

  9. Poly(lauryl acrylate) and poly(stearyl acrylate) grafted multiwalled carbon nanotubes for polypropylene composites

    DEFF Research Database (Denmark)

    Daugaard, Anders Egede; Jankova Atanasova, Katja; Hvilsted, Søren

    2014-01-01

    Two new polymer grafts on an industrial grade multiwalled carbon nanotube (MWCNT) were prepared through a non-oxidative pathway employing controlled free radical polymerization for surface initiated polymer grafting. After photochemical introduction of an ATRP initiator onto the MWCNT......, polymerizations of lauryl or stearyl acrylate were performed, resulting in two novel polymer modifications on the MWCNT (poly(lauryl acrylate) or poly(stearyl acrylate)). The method was found to give time dependent loading of polymers as a function of time (up to 38 wt% for both acrylates), and showed a plateau...... in loading after 12 h of polymerization. The modified nanomaterials were melt mixed into polypropylene composites with very low filler loading (0.3 wt%), whereafter both the thermal and electrical properties were investigated by DSC and dielectric resonance spectroscopy. The electrical properties were found...

  10. Hydrolytic study of the copolymer Poly pyrrole/ Polyethyleneglycol and Poly pyrrole synthesized by plasma

    International Nuclear Information System (INIS)

    Colin, E.; Enriquez, M.A.; Olayo, M.G.; Cruz, G.J.; Carapia, L.; Romero, M.; Morales, J.; Olayo, R.

    2006-01-01

    In this work the study about the hydrolytic compatibility of semiconductor polymers, copolymer Poly pyrrole/ Polyethyleneglycol (PPy/PEG) and Poly pyrrole (PPy) for their possible use as biomaterials. The polymers were synthesized by plasma between 10 and 100 W, with discharges of splendor RF to 13.5 MHz with resistive coupling. The hydrolytic affinity was evaluated calculating the contact angle with solutions of NaCl, NaCl-MgSO 4 and Krebs-Ringer. The results show a hydrophilicity increment due to the increase of the surface ruggedness with the synthesis energy. On the contrary, the crystallinity diminishes when increasing the power in PPy and it stays approximately constant in PPy/PEG. The electric conductivity presents a growth from 2 to 4 magnitude orders in function of the water content in the polymers. (Author)

  11. Poly(ester amide-Poly(ethylene oxide Graft Copolymers: Towards Micellar Drug Delivery Vehicles

    Directory of Open Access Journals (Sweden)

    Gregory J. Zilinskas

    2012-01-01

    Full Text Available Micelles formed from amphiphilic copolymers are promising materials for the delivery of drug molecules, potentially leading to enhanced biological properties and efficacy. In this work, new poly(ester amide-poly(ethylene oxide (PEA-PEO graft copolymers were synthesized and their assembly into micelles in aqueous solution was investigated. It was possible to tune the sizes of the micelles by varying the PEO content of the polymers and the method of micelle preparation. Under optimized conditions, it was possible to obtain micelles with diameters less than 100 nm as measured by dynamic light scattering and transmission electron microscopy. These micelles were demonstrated to encapsulate and release a model drug, Nile Red, and were nontoxic to HeLa cells as measured by an MTT assay. Overall, the properties of these micelles suggest that they are promising new materials for drug delivery systems.

  12. Thermodynamic characterization of poly(4-hydroxystyrene)-g-[poly(propyleneoxide-b-ethylene oxide)] thermoresponsive brush copolymers

    Energy Technology Data Exchange (ETDEWEB)

    Thanassoulas, Angelos, E-mail: athanas@rrp.demokritos.gr [Biomolecuar Physics Laboratory, National Centre for Scientific Research “Demokritos”, 153 10 Aghia Paraskevi (Greece); Papadopoulos, Athanasios [Biomolecuar Physics Laboratory, National Centre for Scientific Research “Demokritos”, 153 10 Aghia Paraskevi (Greece); Pispas, Stergios [Theoretical and Physical Chemistry Institute, National Hellenic Research Foundation, 11635 Athens (Greece); Zhao, Junpeng; Zhang, Guangzhao [Faculty of Materials Science and Engineering, South China University of Technology, Guangzhou 510640 (China); Nounesis, George [Biomolecuar Physics Laboratory, National Centre for Scientific Research “Demokritos”, 153 10 Aghia Paraskevi (Greece)

    2016-08-20

    Highlights: • PPO-b-PEO core-shell brush copolymers exhibit thermoresponsive behavior in aqueous solutions. • Their thermal transitions strongly depend on their architecture and chemical composition. • These copolymer transitions follow a coil-to-globule mechanism. • It is possible to fine-tune their thermoresponsiveness to a wide range of temperatures. - Abstract: Thermoresponsive brush copolymers with poly(4-hydroxystyrene) backbones and poly(propyleneoxide-b-ethylene oxide) side chains were synthesized via a “grafting from” technique. The thermoresponsive behavior of four samples with different compositions has been investigated in dilute aqueous solutions by high-accuracy differential scanning calorimetry measurements. Thermal transitions involving both core contraction and intermolecular aggregation have been observed for all the copolymers in this study. The temperature where these thermal transitions occur is strongly associated to the architecture and chemical composition of the copolymers, allowing for fine-tuning of their thermoresponsiveness in a wide range of temperatures.

  13. Gold Nanoparticles Protected with Thiol-Derivatized Amphiphilic Poly( -caprolactone)-b-poly(acrylic acid)

    DEFF Research Database (Denmark)

    Javakhishvili, Irakli; Hvilsted, Søren

    2008-01-01

    Amphiphilic poly(c-caprolactone)-b-poly(acrylic acid) (HS-PCL-b-PAA) bearing thiol functionality at the PCL terminal has been synthesized by a combination of ring-opening polymerization (ROP) of c-caprolactone (c-CL), esterification of hydroxy chain end with protected mercaptoacetic acid, subsequ....... As a result stable, aggregation-free nanopaticles with moderate dispersity as estimated from UV-visible spectroscopy and transmission electron microscopy (TEM) data were obtained....... chromatography (SEC), nuclear magnetic resonance eR NMR) and infrared (FT IR) spectroscopy. The capacity of the resulting block copolymer in preparation of monolayer-protected gold nanoparticles has been examined by reduction of a gold salt in the presence of this macroligand under thiol-deficient conditions...

  14. Ester Sensing with Poly (Aniline-co-m-aminobenzoic Acid Deposited on Poly (Vinyl Alcohol

    Directory of Open Access Journals (Sweden)

    S. ADHIKARI

    2011-02-01

    Full Text Available Poly (aniline-co-m-aminobenzoic acid was deposited on poly (vinyl alcohol film by in situ oxidative polymerization of the monomers aniline and m-aminobenzoic acid. Sensing experiments were performed on the composite film with the injection of various concentrations of hexenyl acetate and hexenyl butyrate at room temperature. The sensor responded rapidly and reversibly in the presence of hexenyl acetate and hexenyl butyrate vapors which was detected by resistance change of the composite film upon exposure to the vapor. Selectivity tests revealed that the sensor selectively responded to hexenyl butyrate compared to hexenyl acetate. The sensing response has been explained on the basis of FT-IR spectroscopic analysis of the polymer film before and after exposure to the ester vapor.

  15. The use of poly(ethylene terephthalate)-poly(aniline) composite for trypsin immobilisation

    Energy Technology Data Exchange (ETDEWEB)

    Caramori, S.S. [Laboratorio de Quimica de Proteinas, Departamento de Bioquimica e Biologia Molecular, Instituto de Ciencias Biologicas, Universidade Federal de Goias, Cx. Postal 131, 74001-970 Goiania-GO (Brazil)], E-mail: samanthabio@hotmail.com; Fernandes, K.F. [Laboratorio de Quimica de Proteinas, Departamento de Bioquimica e Biologia Molecular, Instituto de Ciencias Biologicas, Universidade Federal de Goias, Cx. Postal 131, 74001-970 Goiania-GO (Brazil)], E-mail: katia@icb.ufg.br

    2008-08-01

    This paper presents trypsin immobilisation on strips of poly(ethylene terephthalate)-poly(aniline), activated with glutaraldehyde (PET-PANIG) composite. The photomicrography of the material showed changes corresponding to the chemical modifications produced in the steps of synthesis. The immobilisation process was very efficient under optimal conditions (18.6%). The immobilised and free enzyme presented the same pH and temperature optimum. PET-PANIG-trypsin was able to hydrolyse casein, albumin, gelatine, and skimmed milk. Km{sub app} value for PET-PANIG-trypsin was very close to Km of the free enzyme for casein. Immobilised trypsin showed higher stability than the free enzyme, with 100% activity after 14 days of storage at 4 deg. C and 100% operational stability after 4 cycles of use.

  16. Copolymerization of poly (ethylene oxide) and poly (methyl methacrylate) initiated by ceric ammonium nitrate

    International Nuclear Information System (INIS)

    Gomes, A.S.; Ferreira, A.A.; Coutinho, F.M.B.; Marinho, J.R.D.

    1984-01-01

    Cerium (IV) salts such as the ceric ammonium nitrate and ceric ammonium sulfate in aqueous acid solution with reducing agents such as alcohols, thiols, glycols, aldehydes and amines are well known initiators of vinyl polymerization. In this work, the polymerization of methyl methacrylate initiated by ceric ammonium nitrate/HNO 3 -poly(ethylene oxide) with hydroxyl end group system was studied in aqueous solution at 25 0 C to obtain block copolymers. (Author) [pt

  17. Poly(Poly(Ethylene Glycol Methyl Ether Methacrylate Grafted Chitosan for Dye Removal from Water

    Directory of Open Access Journals (Sweden)

    Bryan Tsai

    2017-03-01

    Full Text Available As the demand for textile products and synthetic dyes increases with the growing global population, textile dye wastewater is becoming one of the most significant water pollution contributors. Azo dyes represent 70% of dyes used worldwide, and are hence a significant contributor to textile waste. In this work, the removal of a reactive azo dye (Reactive Orange 16 from water by adsorption with chitosan grafted poly(poly(ethylene glycol methyl ether methacrylate (CTS-GMA-g-PPEGMA was investigated. The chitosan (CTS was first functionalized with glycidyl methacrylate and then grafted with poly(poly(ethylene glycol methyl ether methacrylate using a nitroxide-mediated polymerization grafting to approach. Equilibrium adsorption experiments were carried out at different initial dye concentrations and were successfully fitted to the Langmuir and Freundlich adsorption isotherm models. Adsorption isotherms showed maximum adsorption capacities of CTS-g-GMA-PPEGMA and chitosan of 200 mg/g and 150 mg/g, respectively, while the Langmuir equations estimated 232 mg/g and 194 mg/g, respectively. The fundamental assumptions underlying the Langmuir model may not be applicable for azo dye adsorption, which could explain the difference. The Freundlich isotherm parameters, n and K, were determined to be 2.18 and 17.7 for CTS-g-GMA-PPEGMA and 0.14 and 2.11 for chitosan, respectively. An “n” value between one and ten generally indicates favorable adsorption. The adsorption capacities of a chitosan-PPEGMA 50/50 physical mixture and pure PPEGMA were also investigated, and both exhibited significantly lower adsorption capacities than pure chitosan. In this work, CTS-g-GMA-PPEGMA proved to be more effective than its parent chitosan, with a 33% increase in adsorption capacity.

  18. Cytotoxicity of Poly(Alkyl Cyanoacrylate Nanoparticles

    Directory of Open Access Journals (Sweden)

    Einar Sulheim

    2017-11-01

    Full Text Available Although nanotoxicology has become a large research field, assessment of cytotoxicity is often reduced to analysis of one cell line only. Cytotoxicity of nanoparticles is complex and should, preferentially, be evaluated in several cell lines with different methods and on multiple nanoparticle batches. Here we report the toxicity of poly(alkyl cyanoacrylate nanoparticles in 12 different cell lines after synthesizing and analyzing 19 different nanoparticle batches and report that large variations were obtained when using different cell lines or various toxicity assays. Surprisingly, we found that nanoparticles with intermediate degradation rates were less toxic than particles that were degraded faster or more slowly in a cell-free system. The toxicity did not vary significantly with either the three different combinations of polyethylene glycol surfactants or with particle size (range 100–200 nm. No acute pro- or anti-inflammatory activity on cells in whole blood was observed.

  19. Oedipus king: preparing man for the polis

    Directory of Open Access Journals (Sweden)

    José Joaquim Pereira Melo

    2013-09-01

    Full Text Available Having Sophoclean play Oedipus King as a frame of reference, the purpose of this paper is to discuss the educative proposal conceived to the Greek Man as preparation for life in the polis. Although not intentionally, Sophocles pointed out an ideal of Man which, in his perspective, would fulfill Greek societal demands of that time. Such society was divided between myth and rationality and, as a result, Man found Himself in conflict and lacking direction for His life. Given that, Oedipus’ character represented the ideal behavior of that society, and it also made it possible for citizens to reflect and to discuss social, economic and political transformations taking place at that period. Thus Sophocles came up with a hero who was an educational model and a citizen’s as well. Furthermore, such hero differed from that one of the archaic Greek thought.

  20. Biodegradability of Poly(hydroxyalkanoate Materials

    Directory of Open Access Journals (Sweden)

    Keiji Numata

    2009-08-01

    Full Text Available Poly(hydroxyalkanoate (PHA, which is produced from renewable carbon resources by many microorganisms, is an environmentally compatible polymeric material and can be processed into films and fibers. Biodegradation of PHA material occurs due to the action of extracellular PHA depolymerase secreted from microorganisms in various natural environments. A key step in determining the overall enzymatic or environmental degradation rate of PHA material is the degradation of PHA lamellar crystals in materials; hence, the degradation mechanism of PHA lamellar crystals has been studied in detail over the last two decades. In this review, the relationship between crystal structure and enzymatic degradation behavior, in particular degradation rates, of films and fibers for PHA is described.

  1. Poly Cystic Ovarian Syndrome: An Updated Overview

    Science.gov (United States)

    El Hayek, Samer; Bitar, Lynn; Hamdar, Layal H.; Mirza, Fadi G.; Daoud, Georges

    2016-01-01

    Poly Cystic Ovarian Syndrome (PCOS) is one of the most common metabolic and reproductive disorders among women of reproductive age. Women suffering from PCOS present with a constellation of symptoms associated with menstrual dysfunction and androgen excess, which significantly impacts their quality of life. They may be at increased risk of multiple morbidities, including obesity, insulin resistance, type II diabetes mellitus, cardiovascular disease (CVD), infertility, cancer, and psychological disorders. This review summarizes what the literature has so far provided from guidelines to diagnosis of PCOS. It will also present a general overview about the morbidities associated with this disease, specifically with its more severe classic form. Finally, the review will stress on the various aspects of treatment and screening recommendations currently used in the management of this condition. PMID:27092084

  2. Poly Cystic Ovarian Syndrome: an updated overview

    Directory of Open Access Journals (Sweden)

    Samer eEl Hayek

    2016-04-01

    Full Text Available 1.AbstractPoly Cystic Ovarian Syndrome (PCOS is one of the most common metabolic and reproductive disorders among women of reproductive age. Women suffering from PCOS present with a constellation of symptoms associated with menstrual dysfunction and androgen excess, which significantly impacts their quality of life. They may be at increased risk of multiple morbidities, including obesity, insulin resistance, type II diabetes mellitus, cardiovascular disease, infertility, cancer, and psychological disorders. This review summarizes what the literature has so far provided from guidelines to diagnosis of PCOS. It will also present a general overview about the morbidities associated with this disease, specifically with its more severe classic form. Finally, the review will stress on the various aspects of treatment and screening recommendations currently used in the management of this condition.

  3. Solubilization of docetaxel in poly(ethylene oxide)-block-poly(butylene/styrene oxide) micelles.

    Science.gov (United States)

    Elsabahy, Mahmoud; Perron, Marie-Eve; Bertrand, Nicolas; Yu, Ga-Er; Leroux, Jean-Christophe

    2007-07-01

    Poly(ethylene oxide)-block-poly(styrene oxide) (PEO-b-PSO) and PEO-b-poly(butylene oxide) (PEO-b-PBO) of different chain lengths were synthesized and characterized for their self-assembling properties in water by dynamic/static light scattering, spectrofluorimetry, and transmission electron microscopy. The resulting polymeric micelles were evaluated for their ability to solubilize and protect the anticancer drug docetaxel (DCTX) from degradation. The drug release kinetics as well as the cytotoxicity of the loaded micelles were assessed in vitro. All polymers formed micelles with a highly viscous core at low critical association concentrations (hydrolysis under accelerated stability testing conditions. Only PEO-b-PBO bearing 24 BO units afforded significant protection against degradation. In vitro, DCTX was released slower from the latter micelles, but all formulations possessed a similar cytotoxic effect against PC-3 prostate cancer cells. These data suggest that PEO-b-P(SO/BO) micelles could be used as alternatives to conventional surfactants for the solubilization of taxanes.

  4. Adsorption of Poly(ethylene oxide)-Poly(lactide) Copolymers. Effects of Composition and Degradation.

    Science.gov (United States)

    Muller, Dries; Carlsson, Fredrik; Malmsten, Martin

    2001-04-01

    The effect of chemical degradation of two diblock copolymers of poly(ethylene oxide) (E) and poly(lactide) (L), E(39)L(5) and E(39)L(20), on their adsorption at silica and methylated silica was investigated with in situ ellipsometry. Steric stablization of polystyrene dispersions was investigated in relation to degradation. Hydrolysis of the poly(lactide) block of the copolymers was followed at different temperatures and pH by using HPLC to measure the occurrence of lactic acid in solution. The block copolymers were quite stable in pH-unadjusted solution at low temperature, whereas degradation was facilitated by increasing temperature or lowering of the pH. Lower degradation rates of E(39)L(20) where observed at low temperature in comparison with those of E(39)L(5), whereas the degradation rates of the copolymers were quantitatively similar at high temperature. The adsorption of the copolymers at methylated silica substrates decreased with increasing degree of degradation due to the reduction in the ability of hydrophobic block to anchor the copolymer layer at the surface. At silica the adsorption initially increased with increasing degradation, particularly for E(39)L(20) due to deposition of aggregates onto the surface. After extensive degradation the adsorption of the copolymers at both silica and methylated silica resembled that of the corresponding poly(ethylene oxide) homopolymer. Overall, it was found that the eventual reduction in adsorption occurred at a lower degree of degradation for E(39)L(5) than for E(39)L(20). Mean-field calculations showed a reduced anchoring for the block copolymers with decreasing poly(lactide) block length at hydrophobic surfaces. In accordance with this finding, it was observed that polystyrene dispersions were stabilized by E(39)L(20) or E(39)L(5) in a way that depended on both the lactide block length and the degree of degradation. Upon degradation of the hydrophobic block, stabilization of the polystyrene dispersions was

  5. Synthesis and electrical properties of some poly aromatic amines

    International Nuclear Information System (INIS)

    Abd El-Ghaffar, M.A.; Darwich, W.M.; Ahmed, M.A.

    2005-01-01

    Hydrochloric acid doped poly(o-aminophenol), poly(o-aminothiophenol) and poly(m-anisidine) have been prepared via chemical oxidation of their monomers using ammonium persulphate in solution of hydrochloric acid to yield hydrochloric acid salts of the polymers. A.C. conductivity and dielectric constant of the prepared polymers were measured within the temperature range from (300 to 523 K) and frequencies from (1-100 kHz). The values of the activation energy as calculated from the experimental data showed the semiconducting behaviour of the prepared polymers. The results showed that the prepared polymers have the characteristic behaviour of semiconductors and a hoping polaron mechanism was proposed

  6. Behavior of adsorbed Poly-A onto sodium montmorillonite

    Energy Technology Data Exchange (ETDEWEB)

    Palomino-Aquino, Nayeli [Facultad de Estudios Superiores Iztacala, Universidad Nacional Autónoma de México (Mexico); Negrón-Mendoza, Alicia, E-mail: negron@nucleares.unam.mx [Instituto de Ciencias Nucleares, Universidad Nacional Autónoma de México (Mexico)

    2015-07-23

    The adsorption of Poly-A (a polynucleotide consisting of adenine, ribose and a phosphate group), onto a clay mineral, was studied to investigate the extent of adsorption, the site of binding, and the capacity of the clay to protect Poly-A, while it is adsorbed onto the clay, from external sources of energy. The results showed that Poly-A presented a high percentage of adsorption at the edges of the clay and that the survival of the polynucleotide was superior to irradiating the polymer in the absence of the clay.

  7. Gate current for p+-poly PMOS devices under gate injection conditions

    NARCIS (Netherlands)

    Hof, A.J.; Holleman, J.; Woerlee, P.H.

    2001-01-01

    In current CMOS processing both n+-poly and p+-poly gates are used. The I-V –relationship and reliability of n+-poly devices are widely studied and well understood. Gate currents and reliability for p+-poly PMOS devices under gate injection conditions are not well understood. In this paper, the

  8. Application of reactive siloxane prepolymers for the synthesis of thermoplastic poly(ester–siloxanes and poly(ester–ether–siloxanes

    Directory of Open Access Journals (Sweden)

    VESNA V. ANTIC

    2007-02-01

    Full Text Available Thermoplastic poly(ester–siloxanes (TPES and poly(ester–ether–siloxane s, (TPEES, based on poly(butylene terephthalate (PBT as the hard segment and different siloxane-prepolymers as the soft segments, were prepared. The TPES and TPEES were synthesized by catalyzed two-step transesterification from dimethyl terephthalate, (DMT, 1,4-butanediol, (BD and a siloxane-prepolymer. Incorporation of dicarboxypropyl- or disilanol-terminated poly(dimethylsiloxanes (PDMS into the polar poly(butylene terephthalate chains resulted in rather inhomogeneous TPES copolymers, which was a consequence of a prononuced phase separation of the polar and non-polar reactants during synthesis. Two concepts were employed to avoid or reduce phase separation: 1 the use of siloxane-containing triblock prepolymers with hydrophilic terminal blocks, such as ethylene oxide (EO, poly(propylene oxide (PPO or poly(caprolactone (PLC when the terminal blocks serve as a compatibilizer between the extremely non-polar PDMS and the polar DMT and BD, and 2 the use of a high-boiling solvent (1,2,4-trichlorobenzene during the first phase of the reaction. Homogeneity was significantly improved in the case of copolymers based on PCL–PDMS–PCL.

  9. Fabrication of electrospun thermoplastic polyurethane blended poly (l-lactide-co-e-caprolactone) microyarn scaffolds for engineering of female pelvic-floor tissue

    International Nuclear Information System (INIS)

    Hou, Min; Wu, Qingkai; Dai, Miao; Xu, Peirong; Jia, Xiang; Feng, Jie; Gu, Chaochen; Mo, Xiumei

    2015-01-01

    Potential scaffolds for repair of the female pelvic floor require new materials and fabrication by novel methods to improve cellular infiltration. An ‘ideal’ engineered scaffold for pelvic-floor tissue should mimic the three-dimensional (3D) network of the extracellular matrix (ECM), which possesses intricate macro- and nano-architecture. In this study, a series of blended poly(l-lactide-co-ecaprolactone) P(LLA-CL)/thermoplastic polyurethane (TPU) microyarn/microfibrous scaffolds were produced with different weight ratios via dynamic liquid electrospinning and electrospinning. Both biopolymers were dissolved in 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP). Our data showed the mean diameter of microyarn scaffolds to be significantly larger than that of microfibers. Microyarn scaffolds possessed large pore sizes and high porosity. There was no significant difference between the mechanical properties of microyarn and microfibrous scaffolds. Fourier-transform infrared spectroscopy suggested that intermolecular bonds were not present between the molecules of TPU and P(LLA-CL). Morphologic observations using scanning electron microscopy and inverted fluorescence microscopy showed that adipose-derived stem cells labeled with enhanced green fluorescent protein could grow well along or within blend microyarns and migrate within the novel 3D scaffolds. Hematoxylin and eosin staining demonstrated that cell infiltration on microyarn scaffolds was significantly enhanced. The CCK-8 assay showed that microyarns could significantly facilitate cell proliferation compared with microfibrous scaffolds. These results suggested that blend microyarns of P(LLA-CL)/TPU designed to mimic the ECM for female pelvic-floor tissue may be excellent macroporous scaffolds for tissue repair. (paper)

  10. A poly(glycerol sebacate)-coated mesoporous bioactive glass scaffold with adjustable mechanical strength, degradation rate, controlled-release and cell behavior for bone tissue engineering.

    Science.gov (United States)

    Lin, Dan; Yang, Kai; Tang, Wei; Liu, Yutong; Yuan, Yuan; Liu, Changsheng

    2015-07-01

    Various requirements in the field of tissue engineering have motivated the development of three-dimensional scaffold with adjustable physicochemical properties and biological functions. A series of multiparameter-adjustable mesoporous bioactive glass (MBG) scaffolds with uncrosslinked poly(glycerol sebacate) (PGS) coating was prepared in this article. MBG scaffold was prepared by a modified F127/PU co-templating process and then PGS was coated by a simple adsorption and lyophilization process. Through controlling macropore parameters and PGS coating amount, the mechanical strength, degradation rate, controlled-release and cell behavior of the composite scaffold could be modulated in a wide range. PGS coating successfully endowed MBG scaffold with improved toughness and adjustable mechanical strength covering the bearing range of trabecular bone (2-12MPa). Multilevel degradation rate of the scaffold and controlled-release rate of protein from mesopore could be achieved, with little impact on the protein activity owing to an "ultralow-solvent" coating and "nano-cavity entrapment" immobilization method. In vitro studies indicated that PGS coating promoted cell attachment and proliferation in a dose-dependent manner, without affecting the osteogenic induction capacity of MBG substrate. These results first provide strong evidence that uncrosslinked PGS might also yield extraordinary achievements in traditional MBG scaffold. With the multiparameter adjustability, the composite MBG/PGS scaffolds would have a hopeful prospect in bone tissue engineering. The design considerations and coating method of this study can also be extended to other ceramic-based artificial scaffolds and are expected to provide new thoughts on development of future tissue engineering materials. Copyright © 2015 Elsevier B.V. All rights reserved.

  11. Synthesis of Poly(hydroxamic Acid-Poly(amidoxime Chelating Ligands for Removal of Metals from Industrial Wastewater

    Directory of Open Access Journals (Sweden)

    M. R. Lutfor

    2011-01-01

    Full Text Available Synthesis of poly(hydroxamic acid-poly(amidoxime chelating ligands were carried out from poly(methyl acrylate-co-acrylonitrile grafted sago starch and hydroxylamine in alkaline medium. The binding property of metal ions was performed and maximum sorption capacity of the copper was 3.20 mmol/ g and the rate of exchange of some metals was faster, i.e. t½ ≈ 7 min (average. Two types of wastewater containing chromium, zinc, nickel, copper and iron, etc. were used and the heavy metal recovery was found to be highly efficient, about 99% of the metals could be removed from the metal plating wastewater.

  12. Synthesis, Characterization and Biocompatibility of Biodegradable Elastomeric Poly(ether-ester urethane)s Based on Poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) and Poly(ethylene glycol) via Melting Polymerization

    DEFF Research Database (Denmark)

    Li, Zibiao; Yang, Xiaodi; Wu, Linping

    2009-01-01

    Poly(ether-ester urethane)s (PUs) multiblock co-polymers were synthesized from telechelic hydroxylated poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBHHx) and poly(ethylene glycol) (PEG) via a melting polymerization (MP) process using 1,6-hexamethylene diisocyanate (HDI) as a non-toxic couplin...

  13. Poly(3,4-ethylenedioxythiophene)-based glucose biosensors

    NARCIS (Netherlands)

    Kros, A.; Hövell, W.F.M. van; Sommerdijk, N.A.J.M.; Nolte, R.J.M.

    2001-01-01

    Amperometric biosensors for the recognition of glucose oxidase (GOx) based on poly(3,4-ethylenedioxythiophene) (PEDOT) were fabricated for the first time. The resulting biosensor has potential applications for long-term glucose measurements.

  14. Thermally reversible cross-linked poly(ether-urethanes

    Directory of Open Access Journals (Sweden)

    V. Gaina

    2013-07-01

    Full Text Available Cross-linked poly(ether-urethanes were prepared by Diels-Alder (DA reaction of the furan-containing poly(ether-urethane to bismaleimides and showed thermal reversibility evidenced by differential scanning calorimetry and attenuated total reflectance in conjunction with Fourier transform infrared spectroscopy (ATR-FTIR. The furan-containing poly(ether-urethanes were synthesized by the polyaddition reaction of 1,6-hexamethylene diisocyanate (HMDI or 4,4'- dibenzyl diisocyanate (DBDI to poly(tetramethylene ether glycol (PTMEG having Mn = 250, 650, 1000, 1500 and 2000 and 2-[N,N-bis(2-methyl-2-hydroxyethylamino]furfuryl as chain extender by the solution prepolymer method. The molar ratio of isocyanate: PTMEG:chain extender varied from 2:1:1 to 4:1:3, which produces a molar concentration of furyl group ranging between 3.65•10–4 and 1.25•10–3 mol/g.

  15. Diffusivities and Viscosities of Poly(ethylene oxide) Oligomers †

    KAUST Repository

    Hong, Bingbing; Escobedo, Fernando; Panagiotopoulos, Athanassios Z.

    2010-01-01

    Diffusivities and viscosities of poly(ethylene oxide) (PEO) oligomer melts with 1 to 12 repeat units have been obtained from equilibrium molecular dynamics simulations using the TraPPE-UA force field. The simulations generated diffusion coefficients

  16. Poly[n]catenanes: Synthesis of molecular interlocked chains

    Science.gov (United States)

    Wu, Qiong; Rauscher, Phillip M.; Lang, Xiaolong; Wojtecki, Rudy J.; de Pablo, Juan J.; Hore, Michael J. A.; Rowan, Stuart J.

    2017-12-01

    As the macromolecular version of mechanically interlocked molecules, mechanically interlocked polymers are promising candidates for the creation of sophisticated molecular machines and smart soft materials. Poly[n]catenanes, where the molecular chains consist solely of interlocked macrocycles, contain one of the highest concentrations of topological bonds. We report, herein, a synthetic approach toward this distinctive polymer architecture in high yield (~75%) via efficient ring closing of rationally designed metallosupramolecular polymers. Light-scattering, mass spectrometric, and nuclear magnetic resonance characterization of fractionated samples support assignment of the high-molar mass product (number-average molar mass ~21.4 kilograms per mole) to a mixture of linear poly[7-26]catenanes, branched poly[13-130]catenanes, and cyclic poly[4-7]catenanes. Increased hydrodynamic radius (in solution) and glass transition temperature (in bulk materials) were observed upon metallation with Zn2+.

  17. Poly-optimization: a paradigm in engineering design in mechatronics

    Energy Technology Data Exchange (ETDEWEB)

    Tarnowski, Wojciech [Koszalin University of Technology, Department of Control and Driving Systems, Institute of Mechatronics, Nanotechnology and Vacuum Technique, Koszalin (Poland); Krzyzynski, Tomasz; Maciejewski, Igor; Oleskiewicz, Robert [Koszalin University of Technology, Department of Mechatronics and Applied Mechanics, Institute of Mechatronics, Nanotechnology and Vacuum Technique, Koszalin (Poland)

    2011-02-15

    The paper deals with the Engineering Design that is a general methodology of a design process. It is assumed that a designer has to solve a design task as an inverse problem in an iterative way. After each iteration, a decision should be taken on the information that is called a centre of integration in a systematic design system. For this purpose, poly-optimal solutions may be used. The poly-optimization is presented and contrasted against the Multi Attribute Decision Making, and a set of the poly-optimal solutions is defined. Then Mechatronics is defined and its characteristics given, to prove that mechatronic design process vitally needs CAD tools. Three examples are quoted to demonstrate a key role of the poly-optimization in the mechatronic design. (orig.)

  18. Efficiency of poly-generating high temperature fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Margalef, Pere; Brown, Tim; Brouwer, Jacob; Samuelsen, Scott [National Fuel Cell Research Center (NFCRC), University of California, Irvine, CA 92697-3550 (United States)

    2011-02-15

    High temperature fuel cells can be designed and operated to poly-generate electricity, heat, and useful chemicals (e.g., hydrogen) in a variety of configurations. The highly integrated and synergistic nature of poly-generating high temperature fuel cells, however, precludes a simple definition of efficiency for analysis and comparison of performance to traditional methods. There is a need to develop and define a methodology to calculate each of the co-product efficiencies that is useful for comparative analyses. Methodologies for calculating poly-generation efficiencies are defined and discussed. The methodologies are applied to analysis of a Hydrogen Energy Station (H{sub 2}ES) showing that high conversion efficiency can be achieved for poly-generation of electricity and hydrogen. (author)

  19. Poly (ether imide sulfone) membranes from solutions in ionic liquids

    KAUST Repository

    Kim, Dooli; Nunes, Suzana Pereira

    2017-01-01

    A membrane manufacture method based on non-volatile solvents and a high performance polymer, poly (ether imide sulfone) (EXTEM™), is proposed, as greener alternative to currently industrial process. We dissolved EXTEM™ in pure ionic liquids: 1-ethyl

  20. Synthesis and characterization of new optically active poly(amide ...

    African Journals Online (AJOL)

    Synthesis and characterization of new optically active poly(amide-imide)s based on N -trimellitimido- ... Bulletin of the Chemical Society of Ethiopia ... (DMAc), dimethyl sulfoxide (DMSO) and N-methyl-2-pyrrolidone (NMP) at room temperature.

  1. Studies on electrical conductivity of poly phenylene vinylene

    International Nuclear Information System (INIS)

    Khattab, Asaad F.; Ahmad, Saddam M.

    2009-01-01

    Four Pp polymers have been synthesized through Wit ting reaction, 1 poly(p-phenylene vinylene), 2 = poly(p phenylene vinylene-co-m-phenylene vinylene), 3 = poly(p-phenylene vinylene-co-o-phenylene vinylene) and 4 poly(p-phenylene-1,5-hexadiene). Electrical conductivity measurements show that the conductivity of polymer 3 is higher than that of polymers 1 and 2. The dihedral angle measurements indicates that the irregularity of polymer chains is the main reason for this fact. The interruption of chain conjugation by aliphatic segments (polymer 4) will increase the conductivity by increasing the chain mobility.The electrical conductivity of the polymers is increased by doping with iodine and by raising the temperature. The effect of annealing with different temperatures on conductivity was studied; the results show that structural conformation of polymeric chain is the main factor affecting electrical conductivity. (author)

  2. Preparation and Characterization of Sulfonated Poly (ether ether ...

    African Journals Online (AJOL)

    NJD

    2007-08-10

    Aug 10, 2007 ... Preparation and Characterization of Sulfonated Poly (ether ... Currently perfluori- ... with phosphoric acid solution according to the method described earlier.11,12 ... where A is the membrane area available for diffusion; CA is.

  3. Cal Poly Apparel Manufacturing Demonstration - Year 3 Final Technical Report

    National Research Council Canada - National Science Library

    2000-01-01

    .... Since the Southern California apparel industry is primarily small businesses producing low volume fashion products, the Cal Poly Demo factory needed to reflect the size and capability of its customer...

  4. Photophysical processes study for poly (P-substituted styrenes) in solid films and in solutions

    International Nuclear Information System (INIS)

    Al-Hakeem, I.A.

    1985-01-01

    In this work, the absorption and emission spectra of poly (P-NN dimethyl amino styrene), poly (P-Fluoro Styrene), poly (P-CH2OCH3 styrene), poly (P-Methyl (styrene), poly(P-Tertiary butyl styrene) have been studied in solid films and solutions. The effect of added dimethylterph-thalate as a quencher to the fluorescence emission of the polymers used in this work were studied.(5 tabs., 39 figs., 60 refs.)

  5. Antifungal Poly(lactic acid) Films Containing Thymol and Carvone

    OpenAIRE

    Boonruang Kanchana; Chinsirikul Wannee; Hararak Bongkot; Kerddonfag Noppadon; Chonhenchob Vanee

    2016-01-01

    The goal of this study was to develop antifungal poly(lactic acid) films for food packaging applications. The antifungal compounds, thymol and R-(-)-carvone were incorporated into poly(lactic acid) (PLA)-based polymer at 10, 15 and 20% by weight. Film converting process consists of three steps including melt blending, sheet extrusion and biaxial stretching. The incorporation of antifungal compounds into the polymer matrix resulted in decreased Tg and Tm, increased gas permeabilility, reduced ...

  6. Structural characterization of Poly aniline blended with polyacrylamide

    International Nuclear Information System (INIS)

    Fayek, S.A.; El-Sayed, S.M.; Sayed, W.M.

    2007-01-01

    Poly aniline / polyacrylamide blends in presence of different catalysts were prepared. X-ray diffraction studies reveal that the samples produced are crystalline. Optical gap of the blend in the presence of NaCIO 4 used as a catalyst is greater than that in the presence of (NH 4 ) 2 S 2 O 8 as a catalyst. The structure of polyacrylamide (PAM) blended with poly aniline (PANI) were investigated by infrared spectroscopy, Grain size was identified using scanning electron microscopy [SEM

  7. Poly-ADP-ribosylation of proteins responds to cellular perturbations

    International Nuclear Information System (INIS)

    Schneeweiss, F.H.A.; Sharan, R.N.

    1999-01-01

    From the results presented above it is quite obvious that poly-ADP-ribosylation reaction is a sensitive parameter to monitor cellular responses to a wide variety of perturbations. Having developed a monolayer assay system using 32 P-NAD + as a marker, it has become possible to measure levels of cellular ADP-ribosylation more precisely. It has been demonstrated that the trigger of poly-ADP-ribosylation reaction may involve different cellular components for different perturbations. In this, membrane has been found to be important. The study has been particularly informative in the realm of DNA damage and repair following qualitatively different radiation assaults. As poly-ADP-ribosylation in eukaryotic cells primarily affects chromosomal proteins, notably histones, the reaction is strongly triggered in response to single and double strand breaks in DNA. Therefore, level of cellular poly-ADP-ribosylation can potentially be used as a biosensor of radiation induced strand breaks and can be specially useful in clinical monitoring of progress of radiotherapy. The assay of poly-ADP-ribosylation, however, requires use of radiolabelled tracer, e.g. 32 P-NAD + . Due to this, study of poly-ADP-ribosylation can not be extended to monitor effects of incorporated radionuclides. In order to overcome this shortcoming and to make the assay more sensitive and quick, a Western blot immunoassay has been developed. The preliminary indications are that the immunoassay of poly-ADP-ribosylation will fulfil the requirements to use poly-ADP-ribosylation as a sensitive, convenient and clinically applicable biosensor of cell response not only to radiations but also to different perturbations. (orig.)

  8. Adsorption of lead from aqueous solutions by poly (methyl methacrylate)

    International Nuclear Information System (INIS)

    Din, M.; Hussain, R.

    1992-01-01

    The adsorption capability of commercially manufactured poly (methyl methacrylate) for lead in aqueous medium has been investigated. Percent adsorption and distribution coefficient values have been determined in relation to the shaking time, amount of adsorbent, pH effects and concentration of lead in the solution. The experimental results are compatible with Freundlich type of adsorption behavior. It is discernible from the experimental results that poly (methyl methacrylate) can be used for the removal of lead from slightly acidic aqueous solutions. (author)

  9. Macrochain configuration, stucture of free volume and transport properties of poly(1-trimethylsilyl-1-propyne) and poly(1-trimethylgermyl-1-propyne)

    KAUST Repository

    Matson, Samira M.; Rä tzke, Klaus; Shaikh, Muhammad Qasim; Litvinova, Elena G.; Shishatskiy, Sergey M.; Peinemann, Klaus-Viktor; Khotimskiy, Valeriy S.

    2012-01-01

    The relationship between poly(1-trimethylsilyl-1-propyne) (PTMSP) and poly(1-trimethylger- myl-1-propyne) (PTMGP) microstructure, gas permeability and structure of free volume is reported. n-Butane/methane mixed-gas permeation properties of PTMSP

  10. Poly-Tobacco Use among High School Students

    Science.gov (United States)

    Kowitt, Sarah D.; Patel, Tanha; Ranney, Leah M.; Huang, Li-Ling; Sutfin, Erin L.; Goldstein, Adam O.

    2015-01-01

    Although cigarette use by adolescents is declining, emerging tobacco products are becoming increasingly popular and youth may use more than one type of tobacco product. The purposes of this study were: (1) to assess patterns of poly-tobacco use among a representative sample of high school students and (2) to determine how beliefs correlate with poly-tobacco use. Data came from the 2013 North Carolina Youth Tobacco Survey (n = 4092). SAS logistic regression survey procedures were used to account for the complex survey design and sampling weights. Among all high school students in NC in 2013, 29.7% reported current any tobacco use, with 19.1% reporting current poly-tobacco use, and 10.6% reporting current use of only one product. Among poly-tobacco users, 59.3% reported that one of the products they currently used was cigarettes. Positive tobacco product beliefs were found to be significantly associated with poly-tobacco use. Communication campaigns, policy efforts, and future research are needed for prevention, regulation, and control of poly-tobacco use among adolescents, which represents a significant public health problem. PMID:26580636

  11. Characterization of poly-aniline/silicon heterojunction for gamma dosimetry

    International Nuclear Information System (INIS)

    Laranjeira, Jane M.G.; Khoury, Helen J.; Azevedo, Walter M.; Silva Junior, Eronides F. da; Vasconcelos, Elder A.

    2000-01-01

    In this work, we have developed and characterized poly-aniline/silicon heterojunction diodes for dosimetry applications. The poly-aniline thin film (thickness in order of microns) was deposited on n-type Si (1 Ωcm) by spin-coating technique from soluble poly-aniline. Al electrode was evaporated on the back side of Si wafer and a circular gold electrode with an area of 0,0036 cm 2 was evaporated on the poly-aniline film. The UV-visible and infrared characterization of the poly-aniline solution and the poly-aniline film has also been done. The heterojunction presents good rectifying behavior at room temperature and the rectification ratio were found to be 51664 ±1,0 V under ambient conditions. The saturation current densities are of the order of 1,4 μA/cm 2 at -1,0 V. The forward current correspond to the negative polarity on the aluminum electrode side and the ideality factor of diodes was approximately 2. The rectifying characteristics of diodes was changed after interaction with gamma radiation ( 60 Co) and the results shows that this devices has potential for applications in dosimetry for doses in range of 0 to 4000 Gy. (author)

  12. Poly(vinylbenzyl sulfonic acid)-grafted poly(ether ether ketone) membranes

    Energy Technology Data Exchange (ETDEWEB)

    Hwang, Mi-Lim; Choi, Jisun; Woo, Hyun-Su; Kumar, Vinod; Sohn, Joon-Yong; Shin, Junhwa, E-mail: shinj@kaeri.re.kr

    2014-02-15

    Highlights: • PEEK-g-PVBSA, a polymer electrolyte membrane was prepared by a radiation grafting technique. • Poly(ether ether ketone) (PEEK), an aromatic hydrocarbon polymer was used as a grafting backbone film. • The water uptake, proton conductivity, and methanol permeability of the membranes were evaluated. • PEEK-g-PVBSA membranes show considerably lower methanol permeability compared to a Nafion membrane. -- Abstract: In this study, an aromatic hydrocarbon based polymer electrolyte membrane, poly(vinylbenzyl sulfonic acid)-grafted poly(ether ether ketone) (PEEK-g-PVBSA), has been prepared by the simultaneous irradiation grafting of vinylbenzyl chloride (VBC) monomer onto a PEEK film and subsequent sulfonation. Each chemical conversion was monitored by FT-IR and SEM–EDX instruments. The physicochemical properties including IEC, water uptake, proton conductivity, and methanol permeability of the prepared membranes were also investigated and found that the values of these properties increase with the increase of degree of grafting. It was observed that the IEC values of the prepared PEEK-g-PVBSA membranes with 32%, 58%, and 80% DOG values were 0.50, 1.05, and 1.22 meq/g while the water uptakes were 14%, 20%, and 21%, respectively. The proton conductivities (0.0272–0.0721 S/cm at 70 °C) were found to be somewhat lower than Nafion 212 (0.126 S/cm at 70 °C) at a relative humidity of 90%. However, the prepared membranes showed a considerably lower methanol permeability (0.61–1.92 × 10{sup −7} cm{sup 2}/s) compared to a Nafion 212 membrane (5.37 × 10{sup −7} cm{sup 2}/s)

  13. Effect of acid on the aggregation of poly(ethylene xide)-poly(propylene oxide)-poly(ethylene oxide) block copolymers.

    Science.gov (United States)

    Yang, Bin; Guo, Chen; Chen, Shu; Ma, Junhe; Wang, Jing; Liang, Xiangfeng; Zheng, Lily; Liu, Huizhou

    2006-11-23

    The acid effect on the aggregation of poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) block copolymers EO(20)PO(70)EO(20) has been investigated by transmission electron microscopy (TEM), particle size analyzer (PSA), Fourier transformed infrared, and fluorescence spectroscopy. The critical micellization temperature for Pluronic P123 in different HCl aqueous solutions increases with the increase of acid concentration. Additionally, the hydrolysis degradation of PEO blocks is observed in strong acid concentrations at higher temperatures. When the acid concentration is low, TEM and PSA show the increase of the micelle mean diameter and the decrease of the micelle polydispersity at room temperature, which demonstrate the extension of EO corona and tendency of uniform micelle size because of the charge repulsion. When under strong acid conditions, the aggregation of micelles through the protonated water bridges was observed.

  14. Preparation and characterization of reactive blends of poly(lactic acid), poly(ethylene-co-vinyl alcohol), and poly(ethylene-co-glycidyl methacrylate)

    International Nuclear Information System (INIS)

    Warangkhana, Phromma; Rathanawan, Magaraphan; Jana Sadhan, C.

    2015-01-01

    The ternary blends of poly(lactic acid) (PLA), poly(ethylene-co-vinyl alcohol) (EVOH), and poly(ethylene-co-glycidyl methacrylate) (EGMA) were prepared. The role of EGMA as a compatibilizer was evaluated. The weight ratio of PLA:EVOH was 80:20 and the EGMA loadings were varied from 5-20 phr. The blends were characterized as follows: thermal properties by differential scanning calorimetry, morphology by scanning electron microscopy, and mechanical properties by pendulum impact tester, and universal testing machine. The glass transition temperature of PLA blends did not change much when compared with that of PLA. The blends of PLA/EGMA and EVOH/EGMA showed EGMA dispersed droplets where the latter led to poor impact properties. However, the tensile elongation at break and tensile toughness substantially increased upon addition of EGMA to blends of PLA and EVOH. It was noted in tensile test samples that both PLA and EVOH domains fibrillated significantly to produce toughness

  15. Preparation and characterization of reactive blends of poly(lactic acid), poly(ethylene-co-vinyl alcohol), and poly(ethylene-co-glycidyl methacrylate)

    Energy Technology Data Exchange (ETDEWEB)

    Warangkhana, Phromma; Rathanawan, Magaraphan, E-mail: rathanawan.k@chula.ac.th [Chulalongkorn University, Petroleum and Petrochemical College - Bangkok (Thailand); Jana Sadhan, C., E-mail: janas@uakron.edu [The University of Akron, Department of Polymer Engineering, Ohio (United States)

    2015-05-22

    The ternary blends of poly(lactic acid) (PLA), poly(ethylene-co-vinyl alcohol) (EVOH), and poly(ethylene-co-glycidyl methacrylate) (EGMA) were prepared. The role of EGMA as a compatibilizer was evaluated. The weight ratio of PLA:EVOH was 80:20 and the EGMA loadings were varied from 5-20 phr. The blends were characterized as follows: thermal properties by differential scanning calorimetry, morphology by scanning electron microscopy, and mechanical properties by pendulum impact tester, and universal testing machine. The glass transition temperature of PLA blends did not change much when compared with that of PLA. The blends of PLA/EGMA and EVOH/EGMA showed EGMA dispersed droplets where the latter led to poor impact properties. However, the tensile elongation at break and tensile toughness substantially increased upon addition of EGMA to blends of PLA and EVOH. It was noted in tensile test samples that both PLA and EVOH domains fibrillated significantly to produce toughness.

  16. Effect of homopolymer poly(vinyl acetate on compatibility and mechanical properties of poly(propylene carbonate/poly(lactic acid blends

    Directory of Open Access Journals (Sweden)

    J. Gao

    2012-11-01

    Full Text Available A small amount of homopolymer poly(vinyl acetate (PVAc is used to compatibilize the biodegradable blends of poly(propylene carbonate (PPC and poly(lactic acid (PLA. Scanning electron microscopy (SEM and differential scanning calorimetry (DSC results show that PVAc is selectively localized in the PLA phase and at the interface between PPC and PLA phases. As a result, these interface-localized PVAc layers act as not only a compatibilizer to improve the phase dispersion significantly but also a bridge to increase the interfacial adhesion between PPC and PLA phases dramatically. Both of them are believed to be responsible for the enhancement in mechanical properties. This work provides a simple avenue to fabricate eco-friendly PPC/PLA blends with high performance, and in some cases, reducing the demand for petroleumbased plastics such as polypropylene.

  17. Raman spectroscopy of poly (3-hydroxybutyrate) modified with poly (vinyl acetate) by radiation- induced copolymerization

    International Nuclear Information System (INIS)

    Gonzalez, Maykel; Galego Fernandez, Norma; Ortiz del Toro, Pedro; Rapado, Manuel; Paredes

    2007-01-01

    Poly (3-hydroxybutyrate) (PHB) is an important material used in the field of medicine. However in common conditions, PHB has some deficiencies. It is very brittle and slightly hydrophobic polymer. This somewhat limit its applications. Radiation chemistry can be used to improve its chemical properties. In the present study, the substrate, modified by radiation-induced graft copolymerization with vinyl acetate (VAc), was characterized using FTIR and Raman spectroscopy. FTIR spectroscopy did not reveal any significant bands but Raman spectroscopy revealed the formation of a new band that characterize the material

  18. Effect of electronic coupling of Watson-Crick hopping in DNA poly(dA)-poly(dT)

    Science.gov (United States)

    Risqi, A. M.; Yudiarsah, E.

    2017-07-01

    Charge transport properties of poly(dA)-poly(dT) DNA has been studied by using thigh binding Hamiltonian approach. Molecule DNA that we use consist of 32 base pair of adenine (A) and thymine (T) and backbone is consist of phosphate and sugar. The molecule DNA is contacted electrode at both ends. Charge transport in molecule DNA depend on the environment, we studied the effect of electronic coupling of Watson-Crick hopping in poly(dA)-poly(dT) DNA to transmission probability and characteristic I-V. The electronic coupling constant influence charge transport between adenine-thymine base pairs at the same site. Transmission probability is studied by using transfer matrix and scattering matrix method, and the result of transmission probability is used to calculate the characteristic I-V by using formula Landauer Buttiker. The result shows that when the electronic coupling increase then transmission probability and characteristic I-V increase slightly.

  19. Topological characterization of nanocrystalline cellulose reinforced Poly (lactic acid) and Poly-(3-hydroxybutyrate-co-3-hydroxyvalerate) bionanocomposites

    Science.gov (United States)

    Bhat, A. H.; Dasan, Y. K.; Khan, Ihsan Ullah; Ahmad, Faiz; Ayoub, Muhammad

    2016-11-01

    This study was conducted to evaluate the morphological and barrier properties of nanocrystalline cellulose reinforced Poly (lactic acid) and Poly-(3-hydroxybutyrate-co-3-hydroxyvalerate) bionanocomposites. Nanocrystalline cellulose was isolated from waste oil palm empty fruit bunch fiber using Sulphuric acid hydrolysis. Chemical modifications of nanocrystalline cellulose was performed to allow good compatibilization between fiber and the polymer matrices and also to improve dispersion of fillers. Bionanocomposite materials were produced from these nanocrystalline cellulose reinforced Poly (lactic acid) and Poly-(3-hydroxybutyrate-co-3-hydroxyvalerate) using solvent casting and evaporation techniques. The properties of extracted nanocrystalline cellulose were examined using FT-IR spectroscopy, X-ray diffractometer, TEM and AFM. Besides that, the properties of bionanocomposites were examined through FESEM and oxygen permeability properties analysis. Better barrier and morphological properties were obtained for nanocrystalline cellulose reinforced bionanocomposites than for neat polymer blend.

  20. Preparation of poly (styrene)-b-poly (acrylic acid)/{gamma}-Fe{sub 2}O{sub 3} composites

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, L.D. [School of Materials Science and Engineering, Shandong Polytechnic University, Key Laboratory of Processing and Testing Technology of Glass Functional Ceramics of Shandong Province, Daxue Road, Western University Science Park, Jinan 250353 (China); Liu, W.L., E-mail: wlliu@sdu.edu.cn [School of Materials Science and Engineering, Shandong Polytechnic University, Key Laboratory of Processing and Testing Technology of Glass Functional Ceramics of Shandong Province, Daxue Road, Western University Science Park, Jinan 250353 (China); Xiao, C.L.; Yao, J.S.; Fan, Z.P.; Sun, X.L.; Zhang, X.; Wang, L. [School of Materials Science and Engineering, Shandong Polytechnic University, Key Laboratory of Processing and Testing Technology of Glass Functional Ceramics of Shandong Province, Daxue Road, Western University Science Park, Jinan 250353 (China); Wang, X.Q. [State Key Laboratory of Crystal Materials, Shandong University, Jinan 250100 (China)

    2011-12-15

    The use of a block copolymer, poly (styrene)-b-poly (acrylic acid) (PS-b-PAA) to prepare a magnetic nanocomposite was investigated. Poly (styrene)-poly (t-butyl acrylate) block copolymer, being synthesized by atom transfer radical polymerization, was hydrolyzed with hydrochloric acid for obtaining PS-b-PAA. The obtained PS-b-PAA was then compounded with the modified {gamma}-Fe{sub 2}O{sub 3}, and subsequently the magnetic nanocomposite was achieved. The products were characterized by {sup 1}H NMR, FTIR, gel permeation chromatography, thermogravimetric analysis, transmission electron microscopy and vibrating sample magnetometer. The results showed that the nanocomposites exhibited soft magnetism, with the mean diameter of 100 nm approximately. - Highlights: > Magnetic composites were prepared using {gamma}-Fe{sub 2}O{sub 3} and PS-b-PAA. > PS-b-PAA was synthesized by atom transfer radical polymerization. > The obtained composite exhibited soft magnetism.

  1. Heat capacity of poly(lactic acid)

    International Nuclear Information System (INIS)

    Pyda, M.; Bopp, R.C.; Wunderlich, B.

    2004-01-01

    The heat capacity of poly(lactic acid) (PLA) is reported from T=(5 to 600) K as obtained by differential scanning calorimetry (d.s.c.) and adiabatic calorimetry. The heat capacity of solid PLA is linked to its group vibrational spectrum and the skeletal vibrations, the latter being described by a Tarasov equation with Θ 1 =574 K, Θ 2 =Θ 3 =52 K, and nine skeletal vibrations. The calculated and experimental heat capacities agree to ±3% between T=(5 and 300) K. The experimental heat capacity of liquid PLA can be expressed by C p (liquid)=(120.17+0.076T) J · K -1 · mol -1 and has been compared to the ATHAS Data Bank, using contributions of other polymers with the same constituent groups. The glass transition temperature of amorphous PLA occurs at T=332.5 K with a change in heat capacity of 43.8 J · K -1 · mol -1 . Depending on thermal history, semi-crystalline PLA has a melting endotherm between T=(418 and 432) K with variable heats of fusion. For 100% crystalline PLA, the heat of fusion is estimated to be (6.55 ± 0.02) kJ · mol -1 at T=480 K. With these results, the enthalpy, entropy, and Gibbs function of crystalline and amorphous PLA were obtained. For semi-crystalline samples, one can check changes of crystallinity with temperature and judge the presence of rigid-amorphous fractions

  2. Poly-thiosemicarbazide membrane for gold recovery

    KAUST Repository

    Villalobos, Luis Francisco

    2014-11-01

    A novel polymeric membrane adsorber with a high density of adsorption sites that can selectively capture Au(III) ions, is proposed as an efficient alternative to recover gold from dilute solutions. Poly-thiosemicarbazide (PTSC), a polymer that contains one chelate site per monomeric unit, was used to fabricate the membranes. This polymer can be easily processed into membranes by a phase inversion technique, resulting in an open and interconnected porous structure suitable for high flux liquid phase applications. This method overcomes the usual low capacities of membrane adsorbents by selecting a starting material that contains the adsorption sites within it, therefore avoiding the necessity to add an external agent into the membrane matrix. The resulting mechanically stable PTSC membranes can operate in a pressure driven permeation process, which eliminates the diffusion limitations commonly present in packed column adsorption processes. This process can selectively recover 97% of the gold present in a solution containing a 9-fold higher copper concentration, while operating at a flux as high as 1868 L/m2 h. The maximum gold uptake measured without sacrificing the mechanical stability of the membrane was 5.4 mmol Au/g. Furthermore the gold can be easily eluted from the membrane with a 0.1 M thiourea solution and the membrane can be reused for at least three cycles without any decrease in its performance. Finally, the ability of this membrane for recovering metals from real-life samples, like seawater and tap water, was tested with promising results.

  3. Characterization of Active Packaging Films Made from Poly(Lactic Acid)/Poly(Trimethylene Carbonate) Incorporated with Oregano Essential Oil

    OpenAIRE

    Dong Liu; Hongli Li; Lin Jiang; Yongming Chuan; Minglong Yuan; Haiyun Chen

    2016-01-01

    Antimicromial and antioxidant bioactive films based on poly(lactic acid)/poly(trimenthylene carbonate) films incorporated with different concentrations of oregano essential oil (OEO) were prepared by solvent casting. The antimicrobial, antioxidant, physical, thermal, microstructural, and mechanical properties of the resulting films were examined. Scanning electron microscopy analysis revealed that the cross-section of films became rougher when OEO was incorporated into PLA/PTMC blends. Differ...

  4. Effect of halloysite nanotubes on the thermal degradation behaviour of poly(.epsilon.-caprolactone)/poly(lactic acid) microfibrillar composites

    Czech Academy of Sciences Publication Activity Database

    Luyt, A. S.; Kelnar, Ivan

    2017-01-01

    Roč. 60, July (2017), s. 166-172 ISSN 0142-9418 R&D Projects: GA ČR(CZ) GA13-15255S Institutional support: RVO:61389013 Keywords : poly(lactic acid) * poly(epsilon-caprolactone) * halloysite nanotubes Subject RIV: JI - Composite Materials OBOR OECD: Composites (including laminates, reinforced plastics, cermets, combined natural and synthetic fibre fabrics Impact factor: 2.464, year: 2016

  5. Interaction of Zn2+ Ions with Single-Stranded PolyU and PolyC in Neutral Solutions

    Czech Academy of Sciences Publication Activity Database

    Sorokin, V. A.; Usenko, E. L.; Valeev, V. A.; Berezniak, E. G.; Andrushchenko, Valery

    2015-01-01

    Roč. 119, č. 12 (2015), s. 4409-4416 ISSN 1520-6106 R&D Projects: GA ČR GAP208/11/0105; GA ČR GA15-09072S Institutional support: RVO:61388963 Keywords : metal ions * polyU * polyC * metallized DNA * differential UV spectroscopy * thermal denaturation * phase diagram Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 3.187, year: 2015

  6. Poly[(ethylene oxide)-co-(methylene ethylene oxide)]: A hydrolytically-degradable poly(ethylene oxide) platform

    OpenAIRE

    Lundberg, Pontus; Lee, Bongjae F.; van den Berg, Sebastiaan A.; Pressly, Eric D.; Lee, Annabelle; Hawker, Craig J.; Lynd, Nathaniel A.

    2012-01-01

    A facile method for imparting hydrolytic degradability to poly(ethylene oxide) (PEO), compatible with current PEGylation strategies, is presented. By incorporating methylene ethylene oxide (MEO) units into the parent PEO backbone, complete degradation was defined by the molar incorporation of MEO, and the structure of the degradation byproducts was consistent with an acid-catalyzed vinyl-ether hydrolysis mechanism. The hydrolytic degradation of poly[(ethylene oxide)-co-(methylene ethylene oxi...

  7. Doxorubicin-loaded micelles of reverse poly(butylene oxide)-poly(ethylene oxide)-poly(butylene oxide) block copolymers as efficient "active" chemotherapeutic agents.

    Science.gov (United States)

    Cambón, A; Rey-Rico, A; Mistry, D; Brea, J; Loza, M I; Attwood, D; Barbosa, S; Alvarez-Lorenzo, C; Concheiro, A; Taboada, P; Mosquera, V

    2013-03-10

    Five reverse poly(butylene oxide)-poly(ethylene oxide)-poly(butylene oxide) block copolymers, BOnEOmBOn, with BO ranging from 8 to 21 units and EO from 90 to 411 were synthesized and evaluated as efficient chemotherapeutic drug delivery nanocarriers and inhibitors of the P-glycoprotein (P-gp) efflux pump in a multidrug resistant (MDR) cell line. The copolymers were obtained by reverse polymerization of poly(butylene oxide), which avoids transfer reaction and widening of the EO block distribution, commonly found in commercial poly(ethylene oxide)-poly(propylene oxide) block copolymers (poloxamers). BOnEOmBOn copolymers formed spherical micelles of 10-40 nm diameter at lower concentrations (one order of magnitude) than those of equivalent poloxamers. The influence of copolymer block lengths and BO/EO ratios on the solubilization capacity and protective environment for doxorubicin (DOXO) was investigated. Micelles showed drug loading capacity ranging from ca. 0.04% to 1.5%, more than 150 times the aqueous solubility of DOXO, and protected the cargo from hydrolysis for more than a month due to their greater colloidal stability in solution. Drug release profiles at various pHs, and the cytocompatibility and cytotoxicity of the DOXO-loaded micelles were assessed in vitro. DOXO loaded in the polymeric micelles accumulated more slowly inside the cells than free DOXO due to its sustained release. All copolymers were found to be cytocompatible, with viability extents larger than 95%. In addition, the cytotoxicity of DOXO-loaded micelles was higher than that observed for free drug solutions in a MDR ovarian NCI-ADR-RES cell line which overexpressed P-gp. The inhibition of the P-gp efflux pump by some BOnEOmBOn copolymers, similar to that measured for the common P-gp inhibitor verapamil, favored the retention of DOXO inside the cell increasing its cytotoxic activity. Therefore, poly(butylene oxide)-poly(ethylene oxide) block copolymers offer interesting features as cell

  8. Interaction between poly(vinyl pyridine) and poly(2,6-dimethyl-1,4-phenylene oxide) : A copolymer blend miscibility study

    NARCIS (Netherlands)

    de Wit, Joost; van Ekenstein, Gert Alberda; ten Brinke, Gerrit

    2007-01-01

    The phase behavior of blends of poly(2,6-dimethyl-1,4-phenylene oxide) (PPO) with random copolymers of styrene and 2-vinyl pyridine, Poly(S-co-2VP), as well as with random copolymers of styrene and 4-vinyl pyridine, Poly(S-co-4VP), has been investigated in order to estimate the values of the

  9. 40 CFR 721.6660 - Polymer of alkanepolyol and poly-alkyl-poly-iso-cyan-ato-car-bo-mo-no-cycle, acetone oxime...

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Polymer of alkanepolyol and poly-alkyl... Polymer of alkanepolyol and poly-alkyl-poly-iso-cyan-ato-car-bo-mo-no-cycle, acetone oxime-blocked... substance identified generically as a polymer of alkane-polyol and polyalkylpolyisocyanatocarbomonocy- cle...

  10. Influence of acrylonitrile butadiene rubber on recyclability of blends prepared from poly(vinyl chloride) and poly(methyl methacrylate).

    Science.gov (United States)

    Suresh, Sunil S; Mohanty, Smita; Nayak, Sanjay K

    2018-06-01

    The current investigation deals with the recycling possibilities of poly(vinyl chloride) and poly(methyl methacrylate) in the presence of acrylonitrile butadiene rubber. Recycled blends of poly(vinyl chloride)/poly(methyl methacrylate) are successfully formed from the plastic constituents, those are recovered from waste computer products. However, lower impact performance of the blend and lower stability of the poly(vinyl chloride) phase in the recycled blend restricts its further usage in industrial purposes. Therefore, effective utilisation acrylonitrile butadiene rubber in a recycled blend was considered for improving mechanical and thermal performance. Incorporation of acrylonitrile butadiene rubber resulted in the improvement in impact performance as well as elongation-at-break of the recycled blend. The optimum impact performance was found in the blend with 9 wt% acrylonitrile butadiene rubber, which shows 363% of enhancement as compared with its parent blend. Moreover, incorporated acrylonitrile butadiene rubber also stabilises the poly(vinyl chloride) phase present in the recycled blend, similarly Fourier transform infrared spectroscopy studies indicate the interactions of various functionalities present in the recycled blend and acrylonitrile butadiene rubber. In addition to this, thermogravimetric analysis indicates the improvement in the thermal stability of the recycled blend after the addition of acrylonitrile butadiene rubber into it. The existence of partial miscibility in the recycled blend was identified using differential scanning calorimetry and scanning electron microscopy.

  11. Miscibility and Hydrogen Bonding in Blends of Poly(4-vinylphenol/Poly(vinyl methyl ketone

    Directory of Open Access Journals (Sweden)

    Hana Bourara

    2014-10-01

    Full Text Available The miscibility and phase behavior of poly(4-vinylphenol (PVPh with poly(vinyl methyl ketone (PVMK was investigated by differential scanning calorimetry (DSC, Fourier transform infrared spectroscopy (FTIR and scanning electron microscopy (SEM. It was shown that all blends of PVPh/PVMK are totally miscible. A DSC study showed the apparition of a single glass transition (Tg over their entire composition range. When the amount of PVPh exceeds 50% in blends, the obtained Tgs are found to be significantly higher than those observed for each individual component of the mixture, indicating that these blends are capable of forming interpolymer complexes. FTIR analysis revealed the existence of preferential specific interactions via hydrogen bonding between the hydroxyl and carbonyl groups, which intensified when the amount of PVPh was increased in blends. Furthermore, the quantitative FTIR study carried out for PVPh/PVMK blends was also performed for the vinylphenol (VPh and vinyl methyl ketone (VMK functional groups. These results were also established by scanning electron microscopy study (SEM.

  12. Poly(3-hydroxybutyrate and Poly(3-hydroxybutyrate-co-3-hydroxyvalerate: Structure, Property, and Fiber

    Directory of Open Access Journals (Sweden)

    Qingsheng Liu

    2014-01-01

    Full Text Available Poly(3-hydroxybutyrate [P(3HB] and poly(3-hydroxybutyrate-co-3-hydroxyvalerate [P(3HB-co-3HV] are produced by various microorganisms as an intracellular carbon and energy reserve from agricultural feedstocks such as sugars and plant oils under unbalanced growth conditions. P(3HB and P(3HB-co-3HV have attracted the attention of academia and industry because of its biodegradability, biocompatibility, thermoplasticity, and plastic-like properties. This review first introduced the isodimorphism, spherulites, and molecular interaction of P(3HB and P(3HB-co-3HV. In addition, the effects of 3HV content on the melting temperature and crystallization rate were discussed. Then the drawbacks of P(3HB and P(3HB-co-3HV including brittleness, narrow melt processing window, low crystallization rate, slow biodegradation rate in body, and so on were summarized. At last, the preparation, structure, and properties of P(3HB and P(3HB-co-3HV fiber were introduced.

  13. Unraveling the Order and Disorder in Poly(3,4-ethylenedioxythiophene)/Poly(styrenesulfonate) Nanofilms

    KAUST Repository

    Zhou, Jian

    2015-08-03

    Conductive polymer poly(3,4-ethylenedioxythiophene)/poly(styrenesulfonate) (PEDOT/PSS) exhibits a tunable conductivity ranging from 0.1 to 4380 S·cm–1 under different doping and/or dedoping strategies. However, the dependence of macroscopic electrical properties on the evolution of the microstructure is not clearly understood. This is the first study that systematically investigated the spatial arrangement of the ordered and disordered phases in PEDOT/PSS nanofilms by bright-field (BF), high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) combined with electron energy loss spectroscopy (EELS) and element-thickness mapping. Our observations clarify how amorphous PSS hinders electrical transport at various length scales in the PEDOT/PSS films. Moreover, the mechanism for an enhancement in 3 orders of magnitude in electrical conductivity was proved by TEM investigation, which is mainly due to a more uniform dispersion by dedoping that opens PEDOT nanoparticle clusters in PEDOT/PSS films. Our microstructural and electrical studies show that the change in spatial arrangement and interaction of small PEDOT domains plays a considerable role in the final electron transport.

  14. Processing Conditions, Thermal and Mechanical Responses of Stretchable Poly (Lactic Acid)/Poly (Butylene Succinate) Films.

    Science.gov (United States)

    Fortunati, Elena; Puglia, Debora; Iannoni, Antonio; Terenzi, Andrea; Kenny, José Maria; Torre, Luigi

    2017-07-16

    Poly (lactic acid) (PLA) and poly (butylene succinate) (PBS) based films containing two different plasticizers [Acetyl Tributyl Citrate (ATBC) and isosorbide diester (ISE)] at three different contents (15 wt %, 20 wt % and 30 wt %) were produced by extrusion method. Thermal, morphological, mechanical and wettability behavior of produced materials was investigated as a function of plasticizer content. Filmature parameters were also adjusted and optimized for different formulations, in order to obtain similar thickness for different systems. Differential scanning calorimeter (DSC) results and evaluation of solubility parameter confirmed that similar miscibility was obtained for ATBC and ISE in PLA, while the two selected plasticizers resulted as not efficient for plasticization of PBS, to the limit that the PBS-30ATBC resulted as not processable. On the basis of these results, isosorbide-based plasticizer was considered a suitable agent for modification of a selected blend (PLA/PBS 80:20) and two mixing approaches were used to identify the role of ISE in the plasticization process: results from mechanical analysis confirmed that both produced PLA-PBS blends (PLA85-ISE15)-PBS20 and (PLA80-PBS20)-ISE15 could guarantee advantages in terms of deformability, with respect to the PLA80-PBS20 reference film, suggesting that the promising use of these stretchable PLA-PBS based films plasticized with isosorbide can provide novel solutions for food packaging applications.

  15. Polyelectrolyte Complex Nanoparticles of Poly(ethyleneimine and Poly(acrylic acid: Preparation and Applications

    Directory of Open Access Journals (Sweden)

    Martin Müller

    2011-04-01

    Full Text Available In this contribution we outline polyelectrolyte (PEL complex (PEC nanoparticles, prepared by mixing solutions of the low cost PEL components poly(ethyleneimine (PEI and poly(acrylic acid (PAC. It was found, that the size and internal structure of PEI/PAC particles can be regulated by process, media and structural parameters. Especially, mixing order, mixing ratio, PEL concentration, pH and molecular weight, were found to be sensible parameters to regulate the size (diameter of spherical PEI/PAC nanoparticles, in the range between 80–1,000 nm, in a defined way. Finally, applications of dispersed PEI/PAC particles as additives for the paper making process, as well as for drug delivery, are outlined. PEI/PAC nanoparticles mixed directly on model cellulose film showed a higher adsorption level applying the mixing order 1. PAC 2. PEI compared to 1. PEI 2. PAC. Surface bound PEI/PAC nanoparticles were found to release a model drug compound and to stay immobilized due to the contact with the aqueous release medium.

  16. Hollow fibers made from a poly(3-hydroxybutyrate/poly-ε-caprolactone blend

    Directory of Open Access Journals (Sweden)

    2011-07-01

    Full Text Available Since poly(3-hydroxybutyrate (PHB is inherently brittle and possesses poor elastic properties, hollow fibers produced by melt spinning from pure PHB, as described in our earlier study [Macromolecular Materials and Engineering, 2010, 295/6, 585–594], do not meet the required needs regarding the mechanical performance. Besides hardly available PHB copolymers, also blend systems are known to enhance material properties and have thus been considered to be eligible to fabricate flexible or rather pliable hollow fibers based on PHB. Blends of PHB and poly-!-caprolactone (PCL are promising for the application in tissue engineering due to the inherent biocompatibility and biodegradability. A wide range of PHB/PCL compositions have been prepared by melt extrusion. Thermal and mechanical properties of the obtained specimens were analyzed in order to identify miscibility and degree of dispersion as well as to determine the influence on the overall mechanical performance. Even though these constituents are known to be immiscible, PHB/PCL 70/30 was proven to be an adequate composition. This blend showed a highly increased elongation and was found to be easily processable by melt spinning compared to pure PHB. From this blend well defined dimensionally stable bendable hollow fibers were fabricated.

  17. Degradation of poly(2,6-dimethylphenylene oxide) and poly(phenylene sulfide) by gamma irradiation

    International Nuclear Information System (INIS)

    Hill, D.J.T.; Hunter, D.S.; Lewis, D.A.; O'Donnell, J.H.; Pomery, P.J.

    1990-01-01

    Electron spin resonance (ESR) spectroscopy and volatile product analysis have been used to examine the degradation of poly[oxy(2,6-dimethyl-1,4-phenylene)], PPO, and poly(thio-1,4-phenylene), PPS, by γ-radiation. Radiation chemical yields (G-values) for trapped radicals were 0.60 and 0.16 after irradiation at 77 K, and 0.33 and 0.04 after irradiation at 300 K, for PPO and PPS, respectively. The ESR spectra of PPO can be analyzed in terms of PhO·, PhCH 2 · and cyclohexadienyl radicals, whereas PPS contained predominantly photobleachable radical ions. G(H 2 ) = 0.08 and G(CH 4 ) = 0.015 for PPO irradiated at 300 K: G(H 2 ) = 0.03 for PPS. The radicals in PPO indicate main-chain scission of the Ph-O bond and loss of H from CH 3 in equal amounts. The radical ions in PPS decayed without the formation of neutral radicals indicating little bond scission and extremely high radiation resistance, which is confirmed by the low G(R) and G(H 2 ) values. (author)

  18. Anisotropic poly (glycerol sebacate)-poly (ϵ-caprolactone) electrospun fibers promote endothelial cell guidance

    International Nuclear Information System (INIS)

    Gaharwar, Akhilesh K; Nikkhah, Mehdi; Sant, Shilpa; Khademhosseini, Ali

    2015-01-01

    Topographical cell guidance is utilized to engineer highly organized and aligned cellular constructs for numerous tissue engineering applications. Recently, electrospun scaffolds fabricated using poly(glycerol sebacate) (PGS) and poly(ϵ-caprolactone) (PCL) have shown a great promise to support valvular interstitial cell functions for the development of tissue engineered heart valves. However, one of the major drawbacks of PGS-PCL scaffolds is the lack of control over cellular alignment. In this work, we investigate the role of scaffold architecture on the endothelial cell alignment, proliferation and formation of organized cellular structures. In particular, PGS-PCL scaffolds with randomly oriented and highly aligned fibers with tunable mechanical properties were fabricated using electrospinning technique. After one week of culture, endothelial cells on the aligned scaffolds exhibited higher proliferation compared to those cultures on randomly oriented fibrous scaffolds. Furthermore, the endothelial cells reorganized in response to the topographical features of aligned scaffolds forming highly organized cellular constructs. Thus, topographical contact guidance, provided by aligned PGS-PCL scaffolds, is envisioned to be useful in developing cellular structures for vascular tissue engineering. (paper)

  19. Self-assembly of Polystyrene- b -poly(2-vinylpyridine)- b -poly(ethylene oxide) Triblock Terpolymers

    KAUST Repository

    Musteata, Valentina-Elena; Sutisna, Burhannudin; Polymeropoulos, Georgios; Avgeropoulos, Apostolos; Meneau, Florian; Peinemann, Klaus-Viktor; Hadjichristidis, Nikolaos; Nunes, Suzana Pereira

    2017-01-01

    Polystyrene-b-poly(2-vinylpyridine)-b-poly(ethylene oxide) (PS-b-P2VP-b-PEO) terpolymer is a versatile polymer to form isoporous films and membranes, due to the possibility of self-assembly control and the properties of the different blocks, such as the P2VP ability of complexation, and H-bond formation, and the PEO biocompatibility. Copolymers with different block ratios and sizes were synthesized. The correlation between their equilibrium bulk morphology, the self-assembly in dilute and semi-dilute solutions and the non-equilibrium porous structures of membranes, obtained by non-solvent induced phase separation, was investigated and discussed in detail. The characterization was performed by small-angle X-ray scattering (SAXS), scanning (SEM) and transmission electron microscopy (TEM). Hexagonal, cubic and lamellar arrangements were observed. The preparation conditions were optimized and a regular, isoporous morphology, suitable for membrane application, was successfully obtained with PS80.5k-b-P2VP64.4k-b-PEO16.1k.

  20. Unraveling the Order and Disorder in Poly(3,4-ethylenedioxythiophene)/Poly(styrenesulfonate) Nanofilms

    KAUST Repository

    Zhou, Jian; Anjum, Dalaver H.; Lubineau, Gilles; Li, Erqiang; Thoroddsen, Sigurdur T

    2015-01-01

    Conductive polymer poly(3,4-ethylenedioxythiophene)/poly(styrenesulfonate) (PEDOT/PSS) exhibits a tunable conductivity ranging from 0.1 to 4380 S·cm–1 under different doping and/or dedoping strategies. However, the dependence of macroscopic electrical properties on the evolution of the microstructure is not clearly understood. This is the first study that systematically investigated the spatial arrangement of the ordered and disordered phases in PEDOT/PSS nanofilms by bright-field (BF), high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) combined with electron energy loss spectroscopy (EELS) and element-thickness mapping. Our observations clarify how amorphous PSS hinders electrical transport at various length scales in the PEDOT/PSS films. Moreover, the mechanism for an enhancement in 3 orders of magnitude in electrical conductivity was proved by TEM investigation, which is mainly due to a more uniform dispersion by dedoping that opens PEDOT nanoparticle clusters in PEDOT/PSS films. Our microstructural and electrical studies show that the change in spatial arrangement and interaction of small PEDOT domains plays a considerable role in the final electron transport.

  1. Longitudinal acoustic properties of poly(lactic acid) and poly(lactic-co-glycolic acid)

    International Nuclear Information System (INIS)

    Parker, N G; Povey, M J W; Mather, M L; Morgan, S P

    2010-01-01

    Acoustics offers rich possibilities for characterizing and monitoring the biopolymer structures being employed in the field of biomedical engineering. Here we explore the rudimentary acoustic properties of two common biodegradable polymers: poly(lactic acid) and poly(lactic-co-glycolic acid). A pulse-echo technique is developed to reveal the bulk speed of sound, acoustic impedance and acoustic attenuation of small samples of the polymer across a pertinent temperature range of 0-70 0 C. The glass transition appears markedly as both a discontinuity in the first derivative of the speed of sound and a sharp increase in the acoustic attenuation. We further extend our analysis to consider the role of ethanol, whose presence is observed to dramatically modify the acoustic properties and reduce the glass transition temperature of the polymers. Our results highlight the sensitivity of acoustic properties to a range of bulk properties, including visco-elasticity, molecular weight, co-polymer ratio, crystallinity and the presence of plasticizers.

  2. MISCIBILITY AND THERMAL DEGRADATION KINETICS OF POLY-β-ALANINE/POLY(3-HYDROXYPROPIONATE BLENDS

    Directory of Open Access Journals (Sweden)

    Efkan CATIKER

    2016-11-01

    Full Text Available Poly-β-alanine (PBA and poly(3-hidroxypropionate (PHP were synthesized via base-catalyzed hydrogen transfer polymerization (HTP of acrylamide and acrylic acid, respectively. Blends of PBA/PHP with different composition (PHP content, 5% to 75% were studied using FTIR, DSC, TGA, XRD and polarized optical microscope to reveal both miscibility and thermal degradation kinetics of PBA/PHP blends.  Optical images of blends were transparent and entirely uniform. Characteristic IR bands of both components shifted in higher frequencies with increasing fraction of other component.  Melting temperature (Tm, thermal decomposition temperatures (Td and enthalpy of fusion (ΔHf of PHP decreased with increasing PBA fraction in blends. Thermal degradation kinetics of both components were studied by Freeman-Carroll method. Activation energies of thermal degradations of blend components were determined with a good regression coefficients (at least 0.994. Activation energies of decomposition decreased from 224.14 to 86.125 kJmol-1 with increasing PHP content. XRD spectra of blends exhibited lower peak intensities than those of neat polymers. The spectroscopic, thermal and optic methods revealed that PBA and PHP were miscible with a good compatibility in amorphous phase.

  3. Poly(3,4-ethylenedioxythiophene)-Poly(styrenesulfonate) Interlayer Insertion Enables Organic Quaternary Memory.

    Science.gov (United States)

    Cheng, Xue-Feng; Hou, Xiang; Qian, Wen-Hu; He, Jing-Hui; Xu, Qing-Feng; Li, Hua; Li, Na-Jun; Chen, Dong-Yun; Lu, Jian-Mei

    2017-08-23

    Herein, for the first time, quaternary resistive memory based on an organic molecule is achieved via surface engineering. A layer of poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT-PSS) was inserted between the indium tin oxide (ITO) electrode and the organic layer (squaraine, SA-Bu) to form an ITO/PEDOT-PSS/SA-Bu/Al architecture. The modified resistive random-access memory (RRAM) devices achieve quaternary memory switching with the highest yield (∼41%) to date. Surface morphology, crystallinity, and mosaicity of the deposited organic grains are greatly improved after insertion of a PEDOT-PSS interlayer, which provides better contacts at the grain boundaries as well as the electrode/active layer interface. The PEDOT-PSS interlayer also reduces the hole injection barrier from the electrode to the active layer. Thus, the threshold voltage of each switching is greatly reduced, allowing for more quaternary switching in a certain voltage window. Our results provide a simple yet powerful strategy as an alternative to molecular design to achieve organic quaternary resistive memory.

  4. Blends of poly(hydroxybutyrate and poly (epsilon-caprolactone obtained from melting mixture

    Directory of Open Access Journals (Sweden)

    Maria Cecília M. Antunes

    2005-06-01

    Full Text Available Poly(3-hydroxybutyrate (PHB is a thermoplastic polyester with a great potential owing to its biodegradability, bioreabsorbation and biological synthesis from a renewable source. Despite these characteristics, the applications of this polymer are very restricted due to its poor mechanical properties and thermal instability at temperatures above its melting point (around 175°C. Among the possibilities of improvement of these materials, the development of blends is a relatively fast and inexpensive option. Poly(epsilon-caprolactone (PCL is a semi-crystalline polymer that may be used as a biomaterial. It presents good mechanical properties, a low melting point (around 55 °C, and could be a good option to develop PHB blends, maintaining the biodegradability and bioreabsorption properties. The objective of the present work was to obtain blends of PHB and PCL by melting mixture in an internal mixer. The compositions varied from 0 to 30 wt% of PCL. DSC, DMA, and SEM were used to characterize the blends. The blends were found to be imiscible with no indication of interaction either the amorphous or crystalline state. The morphology shows PHB as the matrix and PCL as the dispersed phase.

  5. Phase Separation and Elastic Properties of Poly(Trimethylene Terephthalate-block-poly(Ethylene Oxide Copolymers

    Directory of Open Access Journals (Sweden)

    Elżbieta Piesowicz

    2016-06-01

    Full Text Available A series of poly(trimethylene terephthalate-block-poly(ethylene oxide (PTT-b-PEOT copolymers with different compositions of rigid PTT and flexible PEOT segments were synthesized via condensation in the melt. The influence of the block length and the block ratio on the micro-separated phase structure and elastic properties of the synthesized multiblock copolymers was studied. The PEOT segments in these copolymers were kept constant at 1130, 2130 or 3130 g/mol, whereas the PTT content varied from 30 up to 50 wt %. The phase separation was assessed using differential scanning calorimetry (DSC and dynamic mechanical thermal analysis (DMTA. The crystal structure of the synthesised block copolymers and their microstructure on the manometer scale was evaluated by using WAXS and SAXS analysis. Depending on the PTT/PEOT ratio, but also on the rigid and flexible segment length in PTT-b-PEO copolymers, four different domains were observed i.e.,: a crystalline PTT phase, a crystalline PEO phase (which exists for the whole series based on three types of PEOT segments, an amorphous PTT phase (only at 50 wt % content of PTT rigid segments and an amorphous PEO phase. Moreover, the elastic deformability and reversibility of PTT-b-PEOT block copolymers were studied during a cyclic tensile test. Determined values of permanent set resultant from maximum attained stain (100% and 200% for copolymers were used to evaluate their elastic properties.

  6. Structural control of co-continuous poly(L-lactide)/poly(butylene succinate)/clay nanocomposites.

    Science.gov (United States)

    Zhao, Li; Li, Yongjin; Shimizu, Hiroshi

    2009-04-01

    Poly(L-lactide) (PLLA)/poly(butylene succinate) (PBS) (55/45 w/w) blends with different amounts of nanoclay loadings were prepared using a specially designed high-shear extruder, HSE3000mini, which can reach a maximum shear rate of 4400 sec(-1). The resulted co-continuous structural morphologies were observed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). SEM observation revealed that through the combination of various amounts of nanoclay loadings and processing under various shear conditions, the phase size of co-continuous structures of PLLA/PBS blends can be controlled over a wide range from several tens of micrometers to submicrometers. TEM observation shows that all the nanoclays are selectively dispersed in the PBS phase. We also found that clays in low-shear processed sample were mainly located at the interface of PBS phase, while in high-shear sample, the clays were mainly located inside of the PBS phase. It was considered that the dependence of nanoclay location in the PBS phase on the shear conditions, as well as the changing of the viscosity ratio of PBS and PLLA phase with different amounts of clay loading, play important roles in controlling the phase size of the co-continuous structures of PLLA/PBS blends.

  7. Poly(styrene)-b-poly(DL-lactide) copolymer-based nanoparticles for anticancer drug delivery

    Science.gov (United States)

    Lee, Jae-Young; Kim, Jung Sun; Cho, Hyun-Jong; Kim, Dae-Duk

    2014-01-01

    Poly(styrene)-b-poly(DL-lactide) (PS-PDLLA) copolymer-based nanoparticles (NPs) of a narrow size distribution, negative zeta potential, and spherical shape were fabricated for the delivery of docetaxel (DCT). The particle size was consistently maintained in serum for 24 hours and a sustained drug release pattern was observed for 10 days in the tested formulations. The cytotoxicity of the developed blank NPs was negligible in prostate cancer (PC-3) cells. Cellular uptake and distribution of the constructed NPs containing a hydrophobic fluorescent dye was monitored by confocal laser scanning microscopy (CLSM) for 24 hours. Anti-tumor efficacy of the PS-PDLLA/DCT NPs in PC-3 cells was significantly more potent than that of the group treated with commercially available DCT, Taxotere® (P<0.05). Blood biochemistry tests showed that no serious toxicity was observed with the blank NPs in the liver and kidney. In a pharmacokinetic study of DCT in rats, in vivo clearance of PS-PDLLA/DCT NPs decreased while the half-life in blood increased compared to the Taxotere-treated group (P<0.05). The PS-PDLLA NPs are expected to be a biocompatible and efficient nano-delivery system for anticancer drugs. PMID:24940058

  8. Analysis of Gas Permeability Characteristics of Poly(Lactic Acid/Poly(Butylene Succinate Nanocomposites

    Directory of Open Access Journals (Sweden)

    Amita Bhatia

    2012-01-01

    Full Text Available Gas permeability and morphological properties of nanocomposites prepared by the mixing of poly(lactic acid (PLA, poly(butylene succinate (PBS, and clay was investigated. While the composition of PLA and PBS polymers was fixed as 80% and 20% by weight, respectively, for all the nanocomposites, clay contents varied from 1 to 10 wt%. From the morphological studies using both wide angle X-ray diffraction and transmission electron microscopy, the nanocomposite having 1 wt% of clay was considered to have a mixed morphology of intercalated and delaminated structure, while some clusters or agglomerated particles were detected for nanocomposites having 3 and more than 3 wt% of clay content. However, the average particle size of the dispersed PBS phase was reduced significantly from 7 μm to 30–40 nm with the addition of clay in the blend. The oxygen barrier property was improved significantly as compared to the water vapor. A model based on gas barrier property was used for the validation of the oxygen relative permeabilities of PLA/PBS/clay nanocomposites. PLA/PBS/clay nanocomposites validated the Bharadwaj model up to 3 wt% of clay contents only, while for nanocomposites of higher clay contents the Bharadwaj model was invalid due to the clusters and agglomerates formed.

  9. Self-assembly of Polystyrene- b -poly(2-vinylpyridine)- b -poly(ethylene oxide) Triblock Terpolymers

    KAUST Repository

    Musteata, Valentina-Elena

    2017-11-08

    Polystyrene-b-poly(2-vinylpyridine)-b-poly(ethylene oxide) (PS-b-P2VP-b-PEO) terpolymer is a versatile polymer to form isoporous films and membranes, due to the possibility of self-assembly control and the properties of the different blocks, such as the P2VP ability of complexation, and H-bond formation, and the PEO biocompatibility. Copolymers with different block ratios and sizes were synthesized. The correlation between their equilibrium bulk morphology, the self-assembly in dilute and semi-dilute solutions and the non-equilibrium porous structures of membranes, obtained by non-solvent induced phase separation, was investigated and discussed in detail. The characterization was performed by small-angle X-ray scattering (SAXS), scanning (SEM) and transmission electron microscopy (TEM). Hexagonal, cubic and lamellar arrangements were observed. The preparation conditions were optimized and a regular, isoporous morphology, suitable for membrane application, was successfully obtained with PS80.5k-b-P2VP64.4k-b-PEO16.1k.

  10. Synthesis of thermoplastic poly(ester-olefin elastomers

    Directory of Open Access Journals (Sweden)

    Tanasijević Branka

    2004-01-01

    Full Text Available A series of thermoplastic poly(ester-olefin elastomers, based on poly(ethylene-stat-butylene, HO-PEB-OH, as the soft segment and poly (butylene terephthalate, PBT, as the hard segment, were synthesized by a catalyzed transesterification reaction in solution. The incorporation of soft hydrogenated poly(butadiene segments into the copolyester backbone was accomplished by the polycondensation of α, ω-dihydroxyl telechelic HO-PEB-OH, (PEB Mn = 3092 g/mol with 1,4-butanediol (BD and dimethyl terephthalate (DMT in the presence of a 50 wt-% high boiling solvent i.e., 1,2,4-trichlorobenzene. The molar ratio of the starting comonomers was selected to result in a constant hard to soft weight ratio of 60:40. The synthesis was optimized in terms of both the concentration of catalyst, tetra-n-butyl-titanate (Ti(OBu4, and stabilizer, N,N'-diphenyl-p-phenylenediamine (DPPD, as well as the reaction time. It was found that the optimal catalyst concentration (Ti(OBu4 for the synthesis of these thermoplastic elastomers was 1.0 mmol/mol ester and the optimal DPPD concentration was 1.0 wt-%. The extent of the reaction was followed by measuring the inherent viscosity of the reaction mixture. The effectiveness of the incorporation of the soft segments into the copolymer chains was proved by Soxhlet extraction with chloroform. The molecular structures, composition and the size of the synthesized poly(ester-butylenes were verified by 1H NMR spectroscopy, viscometry of dilute solutions and the complex dynamic melt viscosity. The thermal properties of poly(ester-olefins were investigated by differential scanning calorimetry (DSC. The degree of crystallinity was also determined by DSC. The thermal and thermo-oxidative stability were investigated by thermogravimetric analysis (TGA. The rheological properties of poly(ester-olefins were investigated by dynamic mechanical spectroscopy in the melt and solid state.

  11. CIDADES NEGRAS – PETRÓPOLIS IMPERIAL

    Directory of Open Access Journals (Sweden)

    Renata Aquino

    2014-12-01

    Full Text Available Cidade negra e população negra são o enfoque deste artigo sobre a cidade de Petrópolis na Região Serrana do estado do Rio de Janeiro, visando estabelecer novos parâmetros para discussão do espaço geográfico da região da cidade de Petrópolis por meio de outras explicações sobre o povoamento e desenvolvimento desta localidade. Cidade que a história oficial consagrou como cidade imperial e de colonização alemã, negando de forma ideológica as atividades econômicas da cidade e da região e tornando invisível a existência de população de maioria afrodescendente. Apresentamos neste artigo uma discussão sobre a ideologia da colonização alemã como solução para o Brasil, o que explica a imigração alemã para a localidade e também permite compreender a formação da ideologia sobre as origens populacionais e econômicas deste lugar. Argumentamos contra tal ideologia, reafirmando e investigando a existência de colonizadores africanos a partir das diversas fontes que podem levar ao encontro das inscrições afro, materiais e imateriais, na história e na cultura da região. Partimos da ideia da constituição de um território no período colonial que se deu devido ao fluxo de populações dos arredores, não somente devido à Estrada do Ouro. A base do povoamento da região veio das fazendas que exploravam o trabalho escravizado. Do território ocupado por africanos e afrodescendentes, nasceu a cidade que, posteriormente, instalou alguns grupos de alemães e, nesta fusão populacional, constituiu-se a forte presença de populações negra e mesmo branca, de outra origem que não a alemã. Local que devido à existência da Estrada do Ouro, ligando cidades mineiras ao porto do Rio de Janeiro, recebeu as inscrições de povoamento de africanos e afrodescendente pelos dois séculos antes da fundação oficial da cidade. O artigo se concentra nos documentos que demonstram a existência de população negra na localidade.

  12. Radiolytic stabilization of poly(hydroxybutyrate)

    International Nuclear Information System (INIS)

    Santos, Renata F.S.; Araujo, Elmo S.

    2007-01-01

    Poly(hydroxybutyrate), PHB, is a thermoplastic polyester synthesized by many types of bacteria. PHB is of special interest in the manufacture of medical devices sterilizable by gamma radiation, because of remarkable characteristics like its great biocompatibility and biodegradability. However, ionizing radiation causes main chain scissions of PHB followed by the reduction in its molar mass. Then, the purpose of this study was to investigate the radiolytic stabilization of the structure and properties of Brazilian PHB by commercial additives used in photo and thermo-oxidative stabilization of polymers. Initially, casting solvent films were prepared adding 0.5 wt% of five different additives to the polymer system. These films were irradiated at 25 kGy and investigated viscosity-average molar mass (Mv) changes in order to select the best stabilizer. Among the tested additives only one, antioxidant type, provided a good radiostabilization. New polymeric films were prepared with the antioxidant, whose concentrations (wt%) were 0.3, 0.5, 0.7 and 1.0. In this case, the samples were submitted to doses that varied from 15 to 50 kGy. Viscometric analysis was performed in order to assess the radiation-induced main chain scissions. The G value (scissions/100eV of energy transferred to the system) was also obtained by the viscosity technique. The most effective additive, added to the polymer system at 0.5 wt%, promotes a decrease of 8.6 to 1.5 in G value at a dose range of 0 - 35 kGy. In addition, (FT-IR, NMR-1H) spectroscopic analyses on polymer system were also performed. (author)

  13. Fabrication and characterization of novel multilayered structures by stereocomplexion of poly(D-lactic acid)/poly(L-lactic acid) and self-assembly of polyelectrolytes

    OpenAIRE

    Elena Dellacasa; Li Zhao; Gesheng Yang; Laura Pastorino; Gleb B. Sukhorukov

    2016-01-01

    The enantiomers poly(D-lactic acid) (PDLA) and poly(L-lactic acid) (PLLA) were alternately adsorbed directly on calcium carbonate (CaCO3) templates and on poly(styrene sulfonate) (PSS) and poly(allylamine hydrochloride) (PAH) multilayer precursors in order to fabricate a novel layer-by-layer (LBL) assembly. A single layer of poly(L-lysine) (PLL) was used as a linker between the (PDLA/PLLA)n stereocomplex and the cores with and without the polymeric (PSS/PAH)n/PLL multilayer precursor (PEM). N...

  14. Evaluation of poly(ethylene glycol)-coated monodispersed magnetic poly(2-hydroxyethyl methacrylate) and poly(glycidyl methacrylate) microspheres by PCR

    Czech Academy of Sciences Publication Activity Database

    Horák, Daniel; Hlídková, Helena; Trachtová, Š.; Šlouf, Miroslav; Rittich, B.; Španová, A.

    2015-01-01

    Roč. 68, July (2015), s. 687-696 ISSN 0014-3057 R&D Projects: GA ČR GAP206/12/0381; GA MŠk(CZ) LH14318 Institutional support: RVO:61389013 Keywords : magnetic microspheres * poly(ethylene glycol) * real-time PCR Subject RIV: CD - Macromolecular Chemistry Impact factor: 3.485, year: 2015

  15. Impact of the poly(propylene oxide)-b-poly(dimethylsiloxane)-b-poly(propylene oxide) macrodiols on the surface-related properties of polyurethane copolymers

    Czech Academy of Sciences Publication Activity Database

    Stefanović, I. S.; Godevac, D.; Špírková, Milena; Jovančić, P.; Tešević, V.; Milačić, V.; Pergal, M. V.

    2016-01-01

    Roč. 70, č. 6 (2016), s. 725-738 ISSN 0367-598X R&D Projects: GA ČR(CZ) GA13-06700S Institutional support: RVO:61389013 Keywords : segmented polyurethanes * poly(dimethylsiloxane) * 2D NMR spectroscopy Subject RIV: CD - Macromolecular Chemistry Impact factor: 0.459, year: 2016

  16. Sol–gel hybrid membranes loaded with meso/macroporous SiO{sub 2}, TiO{sub 2}–P{sub 2}O{sub 5} and SiO{sub 2}–TiO{sub 2}–P{sub 2}O{sub 5} materials with high proton conductivity

    Energy Technology Data Exchange (ETDEWEB)

    Castro, Yolanda, E-mail: castro@icv.csic.es [Instituto de Cerámica y Vidrio, Consejo Superior de Investigaciones Científicas (ICV-CSIC), Campus de Cantoblanco, 28049 Madrid (Spain); Mosa, Jadra, E-mail: jmosa@icv.csic.es [Instituto de Cerámica y Vidrio, Consejo Superior de Investigaciones Científicas (ICV-CSIC), Campus de Cantoblanco, 28049 Madrid (Spain); Aparicio, Mario [Instituto de Cerámica y Vidrio, Consejo Superior de Investigaciones Científicas (ICV-CSIC), Campus de Cantoblanco, 28049 Madrid (Spain); Pérez-Carrillo, Lourdes A.; Vílchez, Susana; Esquena, Jordi [Instituto de Química Avanzada de Cataluña, Consejo Superior de Investigaciones Científicas (IQAC-CSIC), CIBER de Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN), Jordi Girona 18-26, 08034 Barcelona (Spain); Durán, Alicia [Instituto de Cerámica y Vidrio, Consejo Superior de Investigaciones Científicas (ICV-CSIC), Campus de Cantoblanco, 28049 Madrid (Spain)

    2015-01-15

    In this work, highly conductive hybrid organic–inorganic membranes loaded with SiO{sub 2}, TiO{sub 2}–P{sub 2}O{sub 5} and SiO{sub 2}–TiO{sub 2}–P{sub 2}O{sub 5} meso/macroporous particles were prepared via a sol–gel process. Meso/macroporous particles were incorporated to hybrid membranes, for improving water retention and enhancing electrochemical performance. These particles with a polymodal pore size distribution were prepared by templating in highly concentrated emulsions, the particles showed a specific surface area between 50 m{sup 2}/g (TiO{sub 2}–P{sub 2}O{sub 5}) and 300 m{sup 2}/g (SiO{sub 2}–TiO{sub 2}–P{sub 2}O{sub 5}). The particles were dispersed in a hybrid silica sol and further sprayed onto glass paper. The films were polymerized and sintered; those loaded with meso/macroporous particles had a homogenous distribution. High temperature proton conductivity measurements confirmed a high water retention. Conductivity of these materials is higher than that of Nafion{sup ®} at higher temperatures (120 °C) (2·10{sup −2} S/cm). This study provides processing guideline to achieve hybrid electrolytes for efficient conduction of protons due to their high surface area and porous structure. - Highlights: • Hybrid electrolyte with meso/macroporous particles were synthesized by sol–gel. • Depositions of hybrid solutions by spraying onto glass substrates were performed. • Proton conductivity was evaluated as a function of composition and porous structure.

  17. Sol–gel hybrid membranes loaded with meso/macroporous SiO2, TiO2–P2O5 and SiO2–TiO2–P2O5 materials with high proton conductivity

    International Nuclear Information System (INIS)

    Castro, Yolanda; Mosa, Jadra; Aparicio, Mario; Pérez-Carrillo, Lourdes A.; Vílchez, Susana; Esquena, Jordi; Durán, Alicia

    2015-01-01

    In this work, highly conductive hybrid organic–inorganic membranes loaded with SiO 2 , TiO 2 –P 2 O 5 and SiO 2 –TiO 2 –P 2 O 5 meso/macroporous particles were prepared via a sol–gel process. Meso/macroporous particles were incorporated to hybrid membranes, for improving water retention and enhancing electrochemical performance. These particles with a polymodal pore size distribution were prepared by templating in highly concentrated emulsions, the particles showed a specific surface area between 50 m 2 /g (TiO 2 –P 2 O 5 ) and 300 m 2 /g (SiO 2 –TiO 2 –P 2 O 5 ). The particles were dispersed in a hybrid silica sol and further sprayed onto glass paper. The films were polymerized and sintered; those loaded with meso/macroporous particles had a homogenous distribution. High temperature proton conductivity measurements confirmed a high water retention. Conductivity of these materials is higher than that of Nafion ® at higher temperatures (120 °C) (2·10 −2  S/cm). This study provides processing guideline to achieve hybrid electrolytes for efficient conduction of protons due to their high surface area and porous structure. - Highlights: • Hybrid electrolyte with meso/macroporous particles were synthesized by sol–gel. • Depositions of hybrid solutions by spraying onto glass substrates were performed. • Proton conductivity was evaluated as a function of composition and porous structure

  18. Omni-PolyA: a method and tool for accurate recognition of Poly(A) signals in human genomic DNA

    KAUST Repository

    Magana-Mora, Arturo

    2017-08-15

    BackgroundPolyadenylation is a critical stage of RNA processing during the formation of mature mRNA, and is present in most of the known eukaryote protein-coding transcripts and many long non-coding RNAs. The correct identification of poly(A) signals (PAS) not only helps to elucidate the 3′-end genomic boundaries of a transcribed DNA region and gene regulatory mechanisms but also gives insight into the multiple transcript isoforms resulting from alternative PAS. Although progress has been made in the in-silico prediction of genomic signals, the recognition of PAS in DNA genomic sequences remains a challenge.ResultsIn this study, we analyzed human genomic DNA sequences for the 12 most common PAS variants. Our analysis has identified a set of features that helps in the recognition of true PAS, which may be involved in the regulation of the polyadenylation process. The proposed features, in combination with a recognition model, resulted in a novel method and tool, Omni-PolyA. Omni-PolyA combines several machine learning techniques such as different classifiers in a tree-like decision structure and genetic algorithms for deriving a robust classification model. We performed a comparison between results obtained by state-of-the-art methods, deep neural networks, and Omni-PolyA. Results show that Omni-PolyA significantly reduced the average classification error rate by 35.37% in the prediction of the 12 considered PAS variants relative to the state-of-the-art results.ConclusionsThe results of our study demonstrate that Omni-PolyA is currently the most accurate model for the prediction of PAS in human and can serve as a useful complement to other PAS recognition methods. Omni-PolyA is publicly available as an online tool accessible at www.cbrc.kaust.edu.sa/omnipolya/.

  19. Preparation of various hydrogels based on poly (Vinyl pyrrolidone) and poly ethylene glycol using gamma and electron irradiation

    International Nuclear Information System (INIS)

    Ajji, Z.

    2006-11-01

    Different hydrogels have been prepared using gamma and electron irradiation; the hydrogels are composed of poly(vinyl pyrolidone) (PVP), poly(ethylene glycol) (PEG). The influence of some process parameters on the properties of the hydrogels has been investigated as: the gel fraction, maximum swelling, swelling kinetics, and mechanical properties. In the first part of this study, hydrogel dressings have been prepared using electron irradiation, and the dressings are composed of poly(vinyl pyrrolidone) (PVP), poly(ethylene glycol) (PEG) and agar. The gel fraction increases with increasing PVP concentration due to increased crosslink density, and decreases with increasing the PEG concentration. PEG seems to act not only as plasticizer but also to modify the gel properties as gelation% and maximum swelling. The prepared hydrogels dressings could be considered as a good barrier against microbes. In the second part, different hydrogels have been prepared based on different concentrations of poly(vinyl pyrrolidone) and using gamma irradiation. The gel fraction and maximum swelling of the hydrogels has been determined. In the third part of the study, different hydrogels have been prepared based on different concentrations of poly(vinyl pyrrolidone) and poly(ethylene glycol) (PEG) with various molecular weights, and using gamma irradiation. The gel fraction and maximum swelling of the hydrogels has been determined. The data show that PEG with low molecular weight needs a high dose for the gelation, and the presence of PVP lowers the needed gelation dose. The maximum swelling decreases with increasing irradiation dose and the PVP concentration, which is due to higher crosslinks between the polymer chains. (author)

  20. Direct laser writing of synthetic poly(amino acid) hydrogels and poly(ethylene glycol) diacrylates by two-photon polymerization

    International Nuclear Information System (INIS)

    Käpylä, Elli; Sedlačík, Tomáš; Aydogan, Dogu Baran; Viitanen, Jouko; Rypáček, František; Kellomäki, Minna

    2014-01-01

    The additive manufacturing technique of direct laser writing by two-photon polymerization (2PP-DLW) enables the fabrication of three-dimensional microstructures with superior accuracy and flexibility. When combined with biomimetic hydrogel materials, 2PP-DLW can be used to recreate the microarchitectures of the extracellular matrix. However, there are currently only a limited number of hydrogels applicable for 2PP-DLW. In order to widen the selection of synthetic biodegradable hydrogels, in this work we studied the 2PP-DLW of methacryloylated and acryloylated poly(α-amino acid)s (poly(AA)s). The performance of these materials was compared to widely used poly(ethylene glycol) diacrylates (PEGdas) in terms of polymerization and damage thresholds, voxel size, line width, post-polymerization swelling and deformation. We found that both methacryloylated and acryloylated poly(AA) hydrogels are suitable to 2PP-DLW with a wider processing window than PEGdas. The poly(AA) with the highest degree of acryloylation showed the greatest potential for 3D microfabrication. - Highlights: • Methacryloylated and acryloylated poly(α-amino acid)s (poly(AA)s) were synthesized. • Direct laser writing by two-photon polymerization (2PP-DLW) of poly(AA)s is shown. • Poly(AA)s have wider processing windows than poly(ethylene glycol) diacrylates. • 3D poly(AA) structures with 80% water content were fabricated