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Sample records for pvp

  1. Electrospun Borneol-PVP Nanocomposites

    Directory of Open Access Journals (Sweden)

    Xiao-Yan Li

    2012-01-01

    Full Text Available The present work investigates the validity of electrospun borneol-polyvinylpyrrolidone (PVP nanocomposites in enhancing drug dissolution rates and improving drug physical stability. Based on hydrogen bonding interactions and via an electrospinning process, borneol and PVP can form stable nanofiber-based composites. FESEM observations demonstrate that composite nanofibers with uniform structure could be generated with a high content of borneol up to 33.3% (w/w. Borneol is well distributed in the PVP matrix molecularly to form the amorphous composites, as verified by DSC and XRD results. The composites can both enhance the dissolution profiles of borneol and increase its physical stability against sublimation for long-time storage by immobilization of borneol molecules with PVP. The incorporation of borneol in the PVP matrix weakens the tensile properties of nanofibers, and the mechanism is discussed. Electrospun nanocomposites can be alternative candidates for developing novel nano-drug delivery systems with high performance.

  2. MISCIBILITY, THERMAL STABILITY AND RETENTION OF PVP FOR CROSSLINKED PVA/PVP BLENDS

    Institute of Scientific and Technical Information of China (English)

    LIANG Guomei; ZHANG Kun; FENG Rongyin

    1994-01-01

    The thermal behavior, miscibility, crystallite conformation and thermal stability of crosslinked(CL-) PVA/PVP blends were studied by DSC and TG methods, respectively. DSC results showed that in the blend, the crystallinity,Tm and Tc of PVA were obviously lower than those of pure PVA; the crystal growth changed from three dimensional to two dimensional and only a single Tg was detected . These facts demonstrated that this crystalline and amorphous blend have good miscibility. TG curves showed that providing the quantity of K2S2O8 added is more than 3 wt % ,in the blends PVA will form a stable CL-network, whose thermal degradation temperature was near to that of PVP. But crosslinking reaction will not take place for PVP. The processes of thermal degradation of CL-blends are based on combining both the thermal degradation of PVP and that of PVA crosslinked with corresponding quantity of K2S2O8 CL-agent, respectively.The UV measurements showed that 75 wt% of PVP may be remained in CL-blend hydrogels crosslinked by adding (3- 5 wt % )K2S2O8.This is mainly due to the stable CL-network formed and the good compatibility and proper entanglement between the composites in the CL-blends.

  3. Nonlinear optical properties of Au/PVP composite thin films

    Institute of Scientific and Technical Information of China (English)

    Shen Hong; Cheng Bo-Lin; Lu Guo-Wei; Wang Wei-Tian; Guan Dong-Yi; Chen Zheng-Hao; Yang Guo-Zhen

    2005-01-01

    Colloidal Au and poly(vinylpyrrolidone) (PVP) composite thin films are fabricated by spin-coating method. Linear optical absorption measurements of the Au/PVP composite films indicate an absorption peak around 530 nm due to the surface plasmon resonance of gold nanoparticles. Nonlinear optical properties are studied using standard Z-scan technique, and experimental results show large optical nonlinearities of the Au/PVP composite films. A large value of films.

  4. Chemoselective hydrogenation of arenes by PVP supported Rh nanoparticles

    DEFF Research Database (Denmark)

    Ibrahim, Mahmoud; Poreddy, Raju; Philippot, Karine

    2016-01-01

    Polyvinylpyrrolidone-stabilized Rh nanoparticles (RhNPs/PVP) of ca. 2.2 nm in size were prepared by the hydrogenation of the organometallic complex [Rh(η3-C3H5)3] in the presence of PVP and evaluated as a catalyst in the hydrogenation of a series of arene substrates as well as levulinic acid...

  5. Properties of radiation synthesized PVP-kappa carrageenan hydrogel blends[PVP; Carrageenan; Hydrogels; Radiation crosslinking; Radiation grafting; Semi-interpenetrating network

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    Abad, L.V. E-mail: lvabad@pnri.dost.gov.ph; Relleve, L.S.; Aranilla, C.T.; Rosa, A.M. dela

    2003-12-01

    Hydrogels have been synthesized from varying concentrations of polyvinyl pyrolidone (PVP) and kappa carrageenan (KC) using gamma radiation. Physical properties such as gel fraction and swelling behavior were determined. Data revealed the presence of a network structure whereby KC is physically entangled into the crosslinked PVP (SIPN). TGA, X-RF and FT-IR analyses of the gel fractions also indicated grafting and crosslinking of the PVP. The degree of grafting and crosslinking depended on the concentrations of KC and PVP. Maximum grafting was obtained at higher KC concentration and lower PVP.

  6. Drug delivery glucantime in PVP/chitosan membranes

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, Maria J.A.; Lugao, Ademar B.; Parra, Duclerc F., E-mail: mariajhho@yahoo.com.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Amato, Valdir S. [Universidade de Sao Paulo (DMIP/FM/USP), Sao Paulo, SP (Brazil). Faculdade de Medicina. Departamento de Molestias Infecciosas e Parasitarias

    2015-07-01

    The current study of polymer science considers the area of biomedical application very important to establish developments in new polymeric materials. Examples of that are hydrogels for controlled release of drugs. In this work, hydrogels of poly (N-2-vinil-pyrrolidone) (PVP) containing chitosan and clay nanoparticles were obtained and characterized to investigate chitosan influence on Glucantime drug delivery. The matrixes were crosslinked by gamma irradiation process with doses of 25 kGy. Hydrogels morphologies were observed by X Ray diffraction (DRX). Atomic Force Microscopy (AFM) and swelling kinetic at 22 °C to study the capacity of water retention and, finally, drug delivery tests were performed 'in vitro'. The system showed higher gel fraction for the matrix with 1.0% of clay and 0.5% of chitosan. In this case, besides the interactions of clay ions with PVP, there are interactions of chitosan amine group with PVP amide group. (author)

  7. Colloids and composite materials Au/Pvp and Ag/Pvp generated by laser ablation in polymeric liquid environment

    Energy Technology Data Exchange (ETDEWEB)

    Larez, J.; Rojas, C. [Universidad Central de Venezuela, Faculty of Science, Center of Experimental Solid State Physics, Paseo Los Ilustres, Los Chaguaramos, Apdo. Postal 20513, Caracas 1020-A (Venezuela, Bolivarian Republic of); Castell, R., E-mail: jlarez@fisica.ciens.ucv.ve [Universidad Simon Bolivar, Department of Physics, Plasma and Laser Spectroscopy Laboratory, Valle de Sartenejas, Baruta, Apdo. Postal 89000, Caracas 1080-A (Venezuela, Bolivarian Republic of)

    2016-11-01

    Pulsed laser ablation of silver and gold targets, immersed in a polymeric solution of Polyvinylpyrrolidone (Pvp), is used to generate colloids and composite metal-polymer. Solutions of Pvp in deionized water at different concentrations are employed. Two Pvp number average molecular weights were considered, 10000 g/mol and 55000 g/mol. The high purity targets are irradiated between 20 min and 40 min with the third harmonic (Thg) (λ = 335 nm) of a Nd:YAG laser operating at a rate of 10 Hz with pulses of 8 ns. Optical spectroscopy in UV and vis regions, scanning electron microscopy, high resolution scanning electron microscopy and X-ray are used to identify and determine the shape and size of the produced particles. Very stable sub-micrometric spherical particles for Au/Pvp and Ag/Pvp samples are obtained with diameters of 0.72 μm and 0.40 μm, respectively. The preparation of colloids is performed in one step and no surfactant or dispersing agent is used in this process. (Author)

  8. Chemoselective hydrogenation of arenes by PVP supported Rh nanoparticles.

    Science.gov (United States)

    Ibrahim, Mahmoud; Poreddy, Raju; Philippot, Karine; Riisager, Anders; Garcia-Suarez, Eduardo J

    2016-12-06

    Polyvinylpyrrolidone-stabilized Rh nanoparticles (RhNPs/PVP) of ca. 2.2 nm in size were prepared by the hydrogenation of the organometallic complex [Rh(η(3)-C3H5)3] in the presence of PVP and evaluated as a catalyst in the hydrogenation of a series of arene substrates as well as levulinic acid and methyl levulinate. The catalyst showed excellent activity and selectivity towards aromatic ring hydrogenation compared to other reported transition metal-based catalysts under mild reaction conditions (room temperature and 1 bar H2). Furthermore, it was shown to be a highly promising catalyst for the hydrogenation of levulinic acid and methyl levulinate in water leading to quantitative formation of the fuel additive γ-valerolactone under moderate reaction conditions compared to previously reported catalytic systems.

  9. An Analysis of Open World PvP in LOTRO's PvMP as a Case Study for PvP Games

    Directory of Open Access Journals (Sweden)

    Toh Weimin

    2014-11-01

    Full Text Available This article focuses on the analysis of emergent gameplay, based on a case study of the author's subjective gameplay experience of Player versus Monster Player (PvMP in The Lord of the Rings Online (LOTRO. The argument presented here is that although there is a core system of Player versus Player (PvP which LOTRO shares with other online games, each type of online game has a specific kind of PvP system which attracts players to engage in the gameplay. For instance, the open world sandbox type of PvP attracts certain players to play in LOTRO's PvMP. One of the main aims of this study is thus to investigate some of the core systems of PvP gameplay in open world sandbox PvP. In this article, LOTRO is shown to offer unique opportunities for studying emergent gameplay in open world games, with particular relevance to PvP studies. Two of the core systems of PvP discussed include the design of the simple gameplay rules to support emergent gameplay, and the community's attitudes towards player's behaviours. The types of emergent gameplay discussed include free play versus negotiated fair play, the players' utilisation of strategies in open world PvP to support collaborative and competitive gameplay, and the changing dynamics of open ended gameplay. It is hoped that the analysis provided in this article would form the­ basis of future work on a more general framework for understanding PvP in other online games.

  10. Bicomponent AgCl/PVP nanofibre fabricated by electrospinning with gel–sol method

    Indian Academy of Sciences (India)

    Jie Bai; Yaoxian Li; Lei Sun; Chaoqun Zhang; Qingbiao Yang

    2009-04-01

    A new series of poly(vinyl pyrrolidone) (PVP) and silver chloride nanoparticles (AgCl) composite fibres have been synthesized by electrospinning and gel–sol technology. We used sol–gel process to prepare AgCl nanoparticles in the PVP solution, and then the solutions were electrospun to obtain AgCl/PVP composite nanofibres. The final products were thoroughly characterized by X-ray powder diffraction (XRD), transmission electron microscopy (TEM), and field-emission scanning electron microscopy (FESEM), which showed the formation of AgCl nanoparticles/PVP composite nanofibres.

  11. 静电纺丝法制备PVP/PVDF复合微/纳米纤维%Electrospinning of PVP/PVDF macro/nanofibers

    Institute of Scientific and Technical Information of China (English)

    盛冰冰; 孔庆山; 纪全; 夏延致

    2008-01-01

    研究了不同条件下聚乙烯吡咯烷酮/聚偏氟乙烯(PVP/PVDF)的N,N-二甲基乙酰胺(DMAc)溶液的静电纺丝.采用扫描电镜(sEM)观察不同条件下制备的PVP/PVDF复合微/纳米纤维的微观形貌,并利用傅立叶变换红外光谱分析(FT-IR)纤维结构特征.结果表明,当PVP:PVDF为6:4时,制得的PVP/PVDF复合微/纳米纤维较好.

  12. Effect of PVP Additive on Properties of Cobalt Ferrite Nanoparticles Prepared by Hydrothermal Method

    Directory of Open Access Journals (Sweden)

    P. Razmjouee

    2015-05-01

    Full Text Available In this investigation, the effect of Polyvinylpyrrolidone (PVP additive on microstructure, morphology and magnetic properties of cobalt ferrite nanoparticles prepared by hydrothermal method was studied. X-ray diffraction (XRD studies in different synthesis conditions showed the formation of cobalt ferrite and cobalt oxide. Comparing IR spectrum of PVP additive, sol prepared before hydrothermal process and C-0.1PVP3, 190 obtained by FTIR spectroscopy indicated the formation of bond between PVP and surface of metallic hydroxide and cobalt ferrite particles, which prevented them from growing and coarsening. Scanning electron microscope (SEM was used to study the morphology of samples. According to vibration sample magnetometer (VSM results, as PVP amount increases from 0.1 to 0.3 volume percent, coercive field increases from 298 to 684 Oe and saturation magnetization decreases from 58 to 51 emu/g.

  13. An Insight into Different Stabilization Mechanisms of Phenytoin Derivatives Supersaturation by HPMC and PVP.

    Science.gov (United States)

    Otsuka, Naoya; Ueda, Keisuke; Ohyagi, Naoko; Shimizu, Kozue; Katakawa, Kazuaki; Kumamoto, Takuya; Higashi, Kenjirou; Yamamoto, Keiji; Moribe, Kunikazu

    2015-08-01

    In this study, we examined the stabilization mechanism of drug supersaturation by hypromellose (HPMC) and polyvinylpirrolidone (PVP). The poorly water-soluble drugs, phenytoin (diphenylhydantoin, DPH), and its synthesized derivatives monomethylphenytoin (MDPH) and dimethylphenytoin (DMDPH) were used. DPH supersaturation was efficiently maintained by both HPMC and PVP. HPMC maintained the supersaturation of MDPH and DMDPH in a similar manner to that of DPH, whereas the ability of PVP to maintain drug supersaturation increased as follows: DPH > MDPH > DMDPH. Caco-2 permeation studies and nuclear magnetic resonance measurements revealed that the permeability and molecular state of the drug in a HPMC solution barely changed. In fact, the solubilization of the drug into PVP changed its apparent permeability and molecular state. The drug solubilization efficiency by PVP was higher and followed the order: DPH > MDPH > DMDPH. The different drug solubilization efficiencies most likely result from the different strengths in the intermolecular interaction between the DPH derivatives and PVP. The difference in the stabilization mechanism of drug supersaturation by HPMC and PVP could determine whether the efficient maintenance of the drug supersaturation was dependent on the drug species. © 2015 Wiley Periodicals, Inc. and the American Pharmacists Association.

  14. Synthesis and Characterization of Amphiphilic Block Copolymer Containing PVP and Poly(5-benzyloxytrimethylene carbonate)

    Institute of Scientific and Technical Information of China (English)

    Ying Xia WANG; Feng HE; Ren Xi ZHUO

    2006-01-01

    Amphiphilic copolymer of 5-benzyloxytrimethylene carbonate (BTMC) with poly (vinyl pyrrolidone) (PVP) was successfully synthesized using immobilized porcine pancreas lipase (IPPL) or SnOct2 as catalyst. Hydroxyl terminated PVP, synthesized with 2-mercaptoethanol as a chain transfer reagent, was employed as a macroinitiator. The resulting copolymers were characterized by GPC, 1H NMR and IR. Increasing the BTMC/PVP-OH feed ratio ([B]/[P])resulted in the increase of Mn of corresponding copolymers and the decrease of Mw/Mn.Immobilized enzyme has comparable catalytic activity to SnOct2 for the copolymerization.

  15. Electrical and Thermal Characterization of Electrospun PVP Nanocomposite Fibers

    Directory of Open Access Journals (Sweden)

    Waseem S. Khan

    2013-01-01

    Full Text Available Polyvinylpyrrolidone (PVP solutions incorporated with multiwall carbon nanotubes (MWCNTs were electrospun at various weight percentages, and then the electrical resistance and some thermal properties of these nanocomposite fibers were determined using a high-accuracy electrical resistance measurement device. During the electrospinning process, system and process parameters, such as concentrations, applied voltage, tip-to-collector distance, and pump speeds, were optimized to receive the consistent nanocomposite fibers. When polymers are used in many industrial applications, they require high electrical and thermal conductivities. Most polymers exhibit low electrical conductivity values; however, in the presence of conductive inclusions, the electrical resistance of the MWCNT fibers was reduced from 50 MΩ to below 5 MΩ, which may be attributed to the higher electrical conductivities of these nanoscale inclusions and fewer voids under the applied loads. This study may open up new possibilities in the field for developing electrically conductive novel nanomaterials and devices for various scientific and technological applications.

  16. Chitosan/zinc oxide-polyvinylpyrrolidone (CS/ZnO-PVP) nanocomposite for better thermal and antibacterial activity.

    Science.gov (United States)

    Karpuraranjith, M; Thambidurai, S

    2017-03-06

    A new biopolymer based ZnO-PVP nanocomposite was successfully synthesized by single step in situ precipitation method using chitosan as biosurfactant, zinc chloride as a source material, PVP as stabilizing agent and sodium hydroxide as precipitating agent. The chemical bonding and crystalline behaviors of chitosan, zinc oxide and PVP were confirmed by FT-IR and XRD analysis. The biopolymer connected ZnO particles intercalated PVP matrix was layer and rod like structure appeared in nanometer range confirmed by HR-SEM and TEM analysis. The surface topography image of CS/ZnO-PVP nanocomposite was obtained in the average thickness of 12nm was confirmed by AFM analysis. Thermal stability of cationic biopolymer based ZnO intercalated PVP has higher stability than CS-PVP and chitosan. Consequently, antimicrobial activity of chitosan/ZnO-PVP matrix acts as a better microbial inhibition activity than PVP-ZnO nanocomposite. The obtained above results demonstrate that CS and ZnO intercalated PVP matrix has better reinforced effect than other components. Therefore, Chitosan/ZnO-PVP nanocomposite may be a promising material for the biomedical applications.

  17. Preparation and properties of PVP/PVDF-HFP microporous polymer electrolyte%PVP/PVDF-HFP微孔聚合物电解质的制备及性能

    Institute of Scientific and Technical Information of China (English)

    杨波; 李新海; 郭华军; 王志兴; 黄思林; 李勇勇

    2012-01-01

    以聚偏氟乙烯-六氟丙烯(PVDF-HFP)和聚乙烯基吡咯烷酮(PVP)为基质材料,采用倒相法,在不同的PVP∶PVDF-HFP配比下合成PVP/PVDF-HFP微孔聚合物电解质膜,将制备的微孔膜浸入电解液中活化得到了一系列锂离子电解质膜,并通过扫描电镜、力学、红外光谱进行能分析.研究结果表明:所制备的微孔聚合物电解质膜在PVP∶PVDF-HFP配比(质量比)为0.2∶1时综合性能最好,其吸液率为210%,抗拉强度为2.86N/mm2,电导率为1.82×10-3S/cm,电化学稳定窗口为5.7V.%PVP/PVDF-HFP micropores membranes based on PVDF-HFP and PVP were prepared by the phase transfer method with different mass ratios of PVP to PVDF-HFP. The membranes were characterized by means of SEM, FTIR, AC impedance and linear scan voltammetry methods. The results show that the optimium mass ratio of PVP to PVDF-HFP is 0.2:1. The liquid absorption rate of the polymer electrolyte is 210%. It shows a good tensile strength of 2.86 N/mm2. The ionic conductivity is 1.82 × 10-3 S/cm, and the electrochemical stable window is S.7 V.

  18. A study on the synthesis of multiple emulsion and multiple capsule using chitosan-PVP system

    Energy Technology Data Exchange (ETDEWEB)

    Jung, K.T.; Shul, Y.G. [Yonsei University, Seoul (Korea, Republic of); Lee, H.; Lee, M.S.; Nam, S.I. [Cheiljaedang Co. (Korea, Republic of)

    1998-04-01

    Multiple capsule was prepared by using chitosan-PVP multiple emulsion system(W/O/W) in which oil and water phase can co-exist simultaneously. In multiple emulsion, chitosan and PVP solution were used for external and internal aqueous phase materials, respectively. And squalane was used for oil phase material. To increase the stability of multiple emulsion, multiple emulsion was ejected into the NaOH solution through the nozzle to form multiple capsule of 2-3 mm in diameter, where the chitosan-PVP composite was used as a wall materials. The hardness of this multiple capsule was found to increase as the amount of PVP increased. Antibacterial property of this multicapsule was tested by E. coli. After 1 h, there was drastic decrease of E. coli population and all the E. coli was diminished after 24 h.

  19. Pt nanostructure electrodes pulse electrodeposited in PVP for electrochemical power sources.

    Science.gov (United States)

    Song, You-Jung; Oh, Jae-Kyung; Park, Kyung-Won

    2008-09-03

    In this work, we demonstrated that Pt nanostructure electrodes could be obtained by the pulse electrodeposition method in polyvinylpyrrolidone (PVP). The nanocrystal particles were confirmed by scanning electron microscopy, transmission electron microscopy and x-ray diffraction methods. The average size of Pt nanoparticles deposited in additive PVP with low and high molecular weight is 3.4 and 2.9 nm, respectively, whereas that of Pt electrodeposited without PVP is 360 nm. This means that the size of Pt nanoparticles can be controlled by PVP, resulting in an increased electrochemical surface area. The resulting Pt nanostructure electrodes showed such an improved performance for both direct methanol fuel cells and dye-sensitized solar cells.

  20. Pt nanostructure electrodes pulse electrodeposited in PVP for electrochemical power sources

    Energy Technology Data Exchange (ETDEWEB)

    Song, You-Jung; Oh, Jae-Kyung; Park, Kyung-Won [Department of Chemical and Environmental Engineering, Soongsil University, Seoul 156-743 (Korea, Republic of)], E-mail: kwpark@ssu.ac.kr

    2008-09-03

    In this work, we demonstrated that Pt nanostructure electrodes could be obtained by the pulse electrodeposition method in polyvinylpyrrolidone (PVP). The nanocrystal particles were confirmed by scanning electron microscopy, transmission electron microscopy and x-ray diffraction methods. The average size of Pt nanoparticles deposited in additive PVP with low and high molecular weight is 3.4 and 2.9 nm, respectively, whereas that of Pt electrodeposited without PVP is 360 nm. This means that the size of Pt nanoparticles can be controlled by PVP, resulting in an increased electrochemical surface area. The resulting Pt nanostructure electrodes showed such an improved performance for both direct methanol fuel cells and dye-sensitized solar cells.

  1. Influence of PVP in magnetic properties of NiSn nanoparticles prepared by polyol method

    Energy Technology Data Exchange (ETDEWEB)

    Bobadilla, L.F., E-mail: lbobadilla@iciq.es [Departamento de Quimica Inorganica e Instituto de Ciencia de Materiales, Centro mixto Universidad de Sevilla-CSIC, Av. Americo Vespucio, 41092 Sevilla (Spain); Garcia, C. [Physics Department, Bogazici University, North Campus KB 331-O, Bebek/Istambul (Turkey); Delgado, J.J. [Departamento de Ciencia de los Materiales e Ingenieria Metalurgica y Quimica Inorganica, Facultad de Ciencias, Universidad de Cadiz, Campus Rio San Pedro, E-11510 Puerto Real, Cadiz (Spain); Sanz, O. [Grupo de Ingenieria Quimica, Departamento de Quimica Aplicada, Facultad de Ciencias Quimicas, UPV/EHU, Paseo Manuel de Lardizabal, 3, 20018 San Sebastian (Spain); Romero-Sarria, F.; Centeno, M.A.; Odriozola, J.A. [Departamento de Quimica Inorganica e Instituto de Ciencia de Materiales, Centro mixto Universidad de Sevilla-CSIC, Av. Americo Vespucio, 41092 Sevilla (Spain)

    2012-11-15

    The influence of PVP on the magnetic properties of NiSn nanoparticles prepared by polyol method has been studied. NiSn nanoparticles exhibit superparamagnetic behavior although there is a ferromagnetic contribution due to particles agglomerated below the blocking temperature. The particle size is controlled by the addiction of PVP in varying amounts. The addition of PVP also favours the particles isolation, narrow the particle size distribution and decrease the interparticle interaction strength increasing the superparamagnetic contribution. - Highlights: Black-Right-Pointing-Pointer Ni{sub x}Sn{sub y} alloys nanoparticles have been prepared by polyol method. Black-Right-Pointing-Pointer NiSn nanoparticles exhibit superparamagnetic behavior. Black-Right-Pointing-Pointer The PVP addition favours the particles isolation.

  2. Synthesis and characterization of semi-IPNs based on PVP and PLLA; Sintese e caracterizacao de semi-IPNs envolvendo os homopolimeros PVP e PLLA

    Energy Technology Data Exchange (ETDEWEB)

    Camilo, A.P.R.; Mano, V., E-mail: mano@ufsj.edu.b [Universidade Federal de Sao Joao del Rei (UFSJ), MG (Brazil). Dept. de Ciencias Naturais; Felisberti, M.I. [Universidade Estadual de Campinas (IQ/UNICAMP), SP (Brazil). Inst. de Quimica

    2010-07-01

    The specific interest in the synthesis of semi-IPNs based on PLLA and PVP homopolymers due to the fact these are biodegradable and biocompatible, which allows us to infer applications in the medical field as sutures, implants, matrices for controlled release of drugs etc. The objective was to prepare a multicomponent material amphiphile in the form of semi-interpenetrating polymer networks, based on poly (L-lactide), PLLA, hydrophobic homopolymer, and poly (vinylpyrrolidone), PVP, hydrophilic component. The preparation of semi-IPN combined the polymerization and crosslinking of N-vinylpyrrolidone in the presence of poly (L-lactide). The products were characterized by spectroscopic and thermal methods. (author)

  3. The Cathinones MDPV and α-PVP Elicit Different Behavioral and Molecular Effects Following Acute Exposure.

    Science.gov (United States)

    Giannotti, Giuseppe; Canazza, Isabella; Caffino, Lucia; Bilel, Sabrine; Ossato, Andrea; Fumagalli, Fabio; Marti, Matteo

    2017-06-23

    Since the mid-to-late 2000s, synthetic cathinones have gained popularity among drug users due to their psychostimulant effects greater than those produced by cocaine and amphetamine. Among them, 3,4-methylenedioxypyrovalerone (MDPV) and 1-phenyl-2-(pyrrolidin-1-yl)pentan-1-one (α-PVP) are ones of the most popular cathinones available in the clandestine market as "bath salts" or "fertilizers." Pre-clinical studies indicate that MDPV and α-PVP induced psychomotor stimulation, affected thermoregulation, and promoted reinforcing properties in rodents. However, a direct comparative analysis on the effects caused by MDPV and α-PVP on the behavior and neuronal activation in rodents is still lacking. Behavioral analyses revealed that both MDPV and α-PVP affect spontaneous and stimulated motor responses. In particular, MDPV showed a greater psychomotor effect than α-PVP in line with its higher potency in blocking the dopamine transporter (DAT). Notably, MDPV was found to be more effective than α-PVP in facilitating spontaneous locomotion and it displayed a biphasic effect in contrast to the monophasically stimulated locomotion induced by α-PVP. In addition to the behavioral results, we also found a different modulation of immediate early genes (IEGs) such as Arc/Arg3.1 and c-Fos in the frontal lobe, striatum, and hippocampus, indicating that these drugs do impact brain homeostasis with changes in neuronal activity that depend on the drug, the brain area analyzed, and the timing after the injection. These results provide the first discrimination between MDPV and α-PVP based on behavioral and molecular data that may contribute to explain, at least in part, their toxicity.

  4. Modifying excitation light dose of novel photosensitizer PVP-Hypericin for photodynamic diagnosis and therapy

    OpenAIRE

    Penjweini, Rozhin; Loew, Hans G.; Eisenbauer, Maria; Kratky, Karl W.

    2013-01-01

    Conventional photodynamic diagnosis (PDD) and therapy (PDT) makes use of photosensitizers that are excited by continuous light irradiation of specific wavelengths. In the case of PDT, the overdose of continuous excitation may lead to an expansion of necrosis in cancer cells or morbidity in healthy surroundings. The present study involves 5-h fluorescence imaging of living human lung epithelial carcinoma cells (A549) in the presence of a novel photosensitizer, PVP-Hypericin (PVP: polyvinylpyrr...

  5. Synthesis and characterization of pectin/PVP hydrogel membranes for drug delivery system.

    Science.gov (United States)

    Mishra, Rakesh K; Datt, Mahesh; Banthia, Ajit K

    2008-01-01

    The purpose of the present study was to develop and design pectin and polyvinyl pyrrolidone (PVP) blended hydrogel membranes (PEVP), with different pectin: PVP ratios (1:0.2, 1:0.4, 1:0.6, 1:0.8 and 1:1 w/w), which were prepared by using a conventional solution casting technique. An attempt has been made to characterize the hydrogel membranes by various instrumental techniques like, FTIR (Fourier transform infrared) spectroscopy, X-ray diffraction (XRD), Differential scanning calorimetry (DSC), tensile strength test and scanning electron microscopy (SEM). The release patterns of the drug (salicylic acid) from the hydrogel membrane were done in three different release mediums (pH 1.4, pH 7.4 and distilled water) and samples were analyzed spectrophotometrically at 294 nm wavelength on a UV Vis spectrophotometer. MTT assay was done to ensure cytocompatibility of the pectin/PVP hydrogel membranes using B16 melanoma cells. FTIR spectroscopy indicated the presence of secondary amide (I) absorption bands. The XRD study shows decrease in crystallinity of the hydrogel membranes with increase in PVP ratio. DSC study shows an increase in T(g) of pectin after blending with PVP. It was found that tensile strength increases with increasing PVP ratios in the hydrogel membranes. The prepared hydrogel membranes were found to be biocompatible with B16 melanoma cells.

  6. Drug embedded PVP coated magnetic nanoparticles for targeted killing of breast cancer cells.

    Science.gov (United States)

    Rose, P Arsula; Praseetha, P K; Bhagat, Madhulika; Alexander, Princy; Abdeen, Sunitha; Chavali, Murthy

    2013-10-01

    Magnetic drug targeting is a drug delivery system that can be used in loco-regional cancer treatment. Coated magnetic particles, called carriers, are very useful for delivering chemotherapeutic drugs. Magnetic carriers were synthesized by co-precipitation of iron oxide followed by coating with polyvinyl pyrrolidone (PVP). Characterization was performed using X-ray diffraction, TEM, TGA, FTIR and UV-Vis Spectroscopy. Magnetite (Fe3O4) remained as the core of the carrier. The amount of PVP bound to the iron oxide nanoparticles was estimated by thermogravimetric analysis (TGA) and the attachment of PVP to the iron oxide nanoparticles confirmed by FTIR analysis. The loading efficiency of Epirubicin hydrochloride onto the PVP coated and uncoated iron oxide nanoparticles was measured at intervals such as 1 hr and 24 hrs by UV-Vis Spectroscopy. The binding of Epirubicin hydrochloride to the PVP coated and uncoated iron oxide nanoparticles were confirmed by FTIR analysis. The present findings showed that Epirubicin hydrochloride loaded PVP coated iron oxide nanoparticles are promising for magnetically targeted drug delivery. The drug displayed increased cell cytotoxicity at lower concentrations when conjugated with the nanoparticles than being administered conventionally as individual drugs.

  7. PVP-b-PEO block copolymers for stable aqueous and ethanolic graphene dispersions.

    Science.gov (United States)

    Perumal, Suguna; Park, Kyung Tae; Lee, Hyang Moo; Cheong, In Woo

    2016-02-15

    The ability to disperse pristine (unfunctionalized) graphene is important for various applications, coating, nanocomposites, and energy related systems. Herein we report that amphiphilic copolymers of poly(4-vinyl pyridine)-block-poly(ethylene oxide) (PVP-b-PEO) are able to disperse graphene with high concentrations about 2.6mg/mL via sonication and centrifugation. Ethanolic and aqueous highly-ordered pyrolytic graphite (HOPG) dispersions with block copolymers were prepared and they were compared with the dispersions stabilized by P-123 Pluronic® (P123) and poly(styrene)-block-poly(ethylene oxide) (PS-b-PEO) synthesized. Transmission electron microscopy, scanning electron microscopy, atomic force microscopy, X-ray diffraction, Raman and UV-visible spectroscopic studies confirmed that PVP-b-PEO block copolymers are better stabilizers for HOPG graphene than P123 and PS-b-PEO. X-ray photoelectron spectroscopy and force-distance (F-d) curve analyses revealed that the nitrogen of vinyl pyridine plays a vital role in better attractive interaction with surface of graphene sheet. Thermogravimetric analysis showed that larger amount of PVP-b-PEO was adsorbed onto graphene with longer poly(4-vinyl pyridine) (PVP) block length and in aqueous medium, respectively, and which was consistent with electrical conductivity decreases. This study presents the dispersion efficiency of graphene using PVP-b-PEO varies substantially depending on the lengths of their hydrophobic (PVP) domains.

  8. Effect of PVP on the synthesis of high-dispersion core–shell barium-titanate–polyvinylpyrrolidone nanoparticles

    Directory of Open Access Journals (Sweden)

    Jinhui Li

    2017-06-01

    Full Text Available Monodispersed nanoparticles consisting of barium titanate (BaTiO3, BT as the core and polyvinylpyrrolidone (PVP as the shell were synthesized in a PVP-assisted low-temperature process in an aqueous solution at ambient pressure. In order to clarify the mechanism of this unique BT–PVP nanoparticle growth and the origin of the dispersion, the concentration and molecular weight of PVP used in the synthesis were varied, and the size and dispersion of the resulting nanoparticles in water were investigated by field-emission scanning electron microscopy and dynamic light scattering. Monodispersed nanoparticles with an average size of 130 nm were obtained by using an intermediate PVP concentration of 100 g/L and a PVP molecular weight of 10,000 g/mol. The thickness of the PVP shell was estimated by thermogravimetric analysis. For the highly dispersed BT–PVP, the thickness of PVP adsorbed on the BT surface was around 3–5 nm. Direct SEM observation of monodispersed BT–PVP in an aqueous solution using a unique sample holder was also demonstrated for the first time.

  9. Evaluate the ability of PVP to inhibit crystallization of amorphous solid dispersions by density functional theory and experimental verify.

    Science.gov (United States)

    Wang, Bing; Wang, Dandan; Zhao, Shan; Huang, Xiaobin; Zhang, Jianbin; Lv, Yan; Liu, Xiaocen; Lv, Guojun; Ma, Xiaojun

    2017-01-01

    In this study, we used density functional theory (DFT) to predict polymer-drug interactions, and then evaluated the ability of poly (vinyl pyrrolidone) (PVP) to inhibit crystallization of amorphous solid dispersions by experimental-verification. Solid dispersions of PVP/resveratrol (Res) and PVP/griseofulvin (Gri) were adopted for evaluating the ability of PVP to inhibit crystallization. The density functional theory (DFT) with the B3LYP was used to calculate polymer-drug and drug-drug interactions. Fourier transform infrared spectroscopy (FTIR) was used to confirm hydrogen bonding interactions. Polymer-drug miscibility and drug crystallinity were characterized by the modulated differential scanning calorimetry (MDSC) and X-ray powder diffraction (XRD). The release profiles were studied to investigate the dissolution advantage. DFT results indicated that EPVP-Res>ERes-Res (E: represents hydrogen bonding energy). A strong interaction was formed between PVP and Res. In addition, Fourier transform infrared spectroscopy (FTIR) analysis showed hydrogen bonding formed between PVP and Res, but not between PVP and Gri. MDSC and XRD results suggested that 70-90wt% PVP/Res and PVP/Gri solid dispersions formed amorphous solid dispersions (ASDs). Under the accelerated testing condition, PVP/Res dispersions with higher miscibility quantified as 90/10wt% were more stable than PVP/Gri dispersions. The cumulative dissolution rate of 90wt% PVP/Res dispersions still kept high after 90days storage due to the strong interaction. However, the cumulative dissolution rate of PVP/Gri solid dispersions significantly dropped because of the recrystallization of Gri. Copyright © 2016 Elsevier B.V. All rights reserved.

  10. Active vaccination attenuates the psychostimulant effects of α-PVP and MDPV in rats.

    Science.gov (United States)

    Nguyen, Jacques D; Bremer, Paul T; Ducime, Alex; Creehan, Kevin M; Kisby, Brent R; Taffe, Michael A; Janda, Kim D

    2017-04-01

    Recreational use of substituted cathinones continues to be an emerging public health problem in the United States; cathinone derivatives α-pyrrolidinopentiophenone (α-PVP) and 3,4-methylenedioxypyrovalerone (MDPV), which have been linked to human fatalities and show high potential for abuse liability in animal models, are of particular concern. The objective of this study was to develop an immunotherapeutic strategy for attenuating the effects of α-PVP and MDPV in rats, using drug-conjugate vaccines created to generate antibodies with neutralizing capacity. Immunoconjugates (α-PVP-KLH and MDPV-KLH) or the control carrier protein, keyhole limpet hemocyanin (KLH), were administered to groups (N = 12) of male Sprague-Dawley rats on Weeks 0, 2 and 4. Groups were administered α-PVP or MDPV (0.0, 0.25, 0.5, 1.0, 5.0 mg/kg, i.p.) in acute drug challenges and tested for changes in wheel activity. Increased wheel activity produced by α-PVP or MDPV in the controls was attenuated in the α-PVP-KLH and MDPV-KLH vaccinated groups, respectively. Rectal temperature decreases produced by MDPV in the controls were reduced in duration in the MDPV-KLH vaccine group. A separate group (N = 19) was trained to intravenously self-administer α-PVP (0.05, 0.1 mg/kg/inf) and vaccinated with KLH or α-PVP-KLH, post-acquisition. Self-administration in α-PVP-KLH rats was initially higher than in the KLH rats but then significantly decreased following a final vaccine booster, unlike the stable intake of KLH rats. The data demonstrate that active vaccination provides functional protection against the effects of α-PVP and MDPV, in vivo, and recommend additional development of vaccines as potential therapeutics for mitigating the effects of designer cathinone derivatives. Copyright © 2016 Elsevier Ltd. All rights reserved.

  11. Solubilities of crystalline drugs in polymers: an improved analytical method and comparison of solubilities of indomethacin and nifedipine in PVP, PVP/VA, and PVAc.

    Science.gov (United States)

    Sun, Ye; Tao, Jing; Zhang, Geoff G Z; Yu, Lian

    2010-09-01

    A previous method for measuring solubilities of crystalline drugs in polymers has been improved to enable longer equilibration and used to survey the solubilities of indomethacin (IMC) and nifedipine (NIF) in two homo-polymers [polyvinyl pyrrolidone (PVP) and polyvinyl acetate (PVAc)] and their co-polymer (PVP/VA). These data are important for understanding the stability of amorphous drug-polymer dispersions, a strategy actively explored for delivering poorly soluble drugs. Measuring solubilities in polymers is difficult because their high viscosities impede the attainment of solubility equilibrium. In this method, a drug-polymer mixture prepared by cryo-milling is annealed at different temperatures and analyzed by differential scanning calorimetry to determine whether undissolved crystals remain and thus the upper and lower bounds of the equilibrium solution temperature. The new annealing method yielded results consistent with those obtained with the previous scanning method at relatively high temperatures, but revised slightly the previous results at lower temperatures. It also lowered the temperature of measurement closer to the glass transition temperature. For D-mannitol and IMC dissolving in PVP, the polymer's molecular weight has little effect on the weight-based solubility. For IMC and NIF, the dissolving powers of the polymers follow the order PVP > PVP/VA > PVAc. In each polymer studied, NIF is less soluble than IMC. The activities of IMC and NIF dissolved in various polymers are reasonably well fitted to the Flory-Huggins model, yielding the relevant drug-polymer interaction parameters. The new annealing method yields more accurate data than the previous scanning method when solubility equilibrium is slow to achieve. In practice, these two methods can be combined for efficiency. The measured solubilities are not readily anticipated, which underscores the importance of accurate experimental data for developing predictive models.

  12. Preparation and properties of hydrogels of PVA/PVP/chitosan by radiation

    Energy Technology Data Exchange (ETDEWEB)

    Nho, Y. C.; Park, K. R. [KAERI, Taejon (Korea, Republic of)

    2001-05-01

    The radiation can induce chemical reaction to modify polymer under even the solid condition or in the low temperature. The radiation crosslinking can be easily adjusted and is easily reproducible by controlling the radiation dose. The finished product contains no residuals of substances required to initiate the chemical crosslinking which can restrict the application possibilities. In these studies, hydrogels from a mixture of chitosan and polyvinyl alcohol(PVA)/Poly-N-vinylpyrrolidone(PVP) were made by 'freezing and thawing', or gamma-ray irradiation or two steps of 'freezing and thawing', and gamma-ray irradiation or two steps of 'freezing and thawing' and gamma-ray irradiation for wound dressing. The mechanical properties such as gelation, water absorptivity, and gel strength were examined to evaluate the hydrogels for wound dressing. The composition of PVA:PVP was 60:40, PVA/PVP: chitosan ratio was in the range of 9:1 -7:3, and the solid concentration of PVA/PVP/chitosan solution was 15wt%. Gamma irradiation doses of 25, 35, 50, 60 and 70kGy, respectively were exposed to a mixture of PVA/PVP/chitosan to evaluate the effect of irradiation dose on the mechanical properties of hydrogels. Water-soluble chitosan was used to in this experiment. The mechanical properties of hydrogels such as gelation and gel strength was higher when two steps of 'freezing and thawing' and irradiation were used than only 'freezing and thawing' was utilized. Gel content was influenced slightly by PVA/PVP:chitosan composition and irradiation dose, but swelling was done greatly by them. Swelling percent was much increased as the composition of chitosan in PVA/PVP/chitosan increased.

  13. Structural, dielectric and electromagnetic shielding properties of Ni–Cu nanoferrite/PVP composites

    Energy Technology Data Exchange (ETDEWEB)

    Madhu, B.J., E-mail: bjmadhu@gmail.com [Post Graduate Department of Physics, Government Science College, Chitradurga 577 501 (India); Ashwini, S.T. [Post Graduate Department of Physics, Government Science College, Chitradurga 577 501 (India); Shruthi, B. [Department of Chemistry, Dr. Ambedkar Institute of Technology, Bangalore 560 056 (India); Divyashree, B.S.; Manjunath, A. [Post Graduate Department of Physics, Government Science College, Chitradurga 577 501 (India); Jayanna, H.S. [Department of Physics, Kuvempu University, Shankaraghatta 577 451 (India)

    2014-08-01

    Highlights: • Ni–Cu nanoferrite particles were prepared using solution combustion method. • Dielectric behavior and a.c. conductivity of the Ni–Cu nanoferrite/PVP composites were studied. • Electrical conduction mechanism was in accordance with the electron hopping model. • The EMI shielding effectiveness (SE) of Ni–Cu nanoferrite/PVP composites was investigated. • Ni–Cu nanoferrite/PVP composites were demonstrated as a promising efficient material for the absorbing of electromagnetic waves. - Abstract: Nickel–copper (Ni–Cu) nanoferrites were synthesized using solution combustion method. The XRD pattern of the as prepared and calcinated samples at 600 °C revealed the presence of both cubic NiFe{sub 2}O{sub 4} and tetragonal CuFe{sub 2}O{sub 4} phases. Frequency and temperature dependence of dielectric constant (ε′), dielectric loss (tan δ) and a.c. conductivity (σ{sub ac}) studies have been undertaken on the Ni–Cu nanoferrites blended with polyvinylpyrrolidone (PVP) in the range 100 Hz–5 MHz. Studies have shown increasing trend of ε′, tan δ and σ{sub ac} with the increase of temperature for Ni–Cu ferrite nanoparticles in the PVP matrix. Further, frequency and temperature dependence of electromagnetic interference (EMI) shielding effectiveness (SE) is studied. The SE is found to increase with the temperature and decrease with an increase in the frequency. Ni–Cu nanoferrite/PVP composites were demonstrated a promising efficient material for the absorbing of electromagnetic waves because of a large amount of dipole polarizations in the polymer backbone and the interfaces of the ferrite nanoparticles and PVP matrix.

  14. Development of high refractive ZnS/PVP/PDMAA hydrogel nanocomposites for artificial cornea implants.

    Science.gov (United States)

    Zhang, Quanyuan; Su, Kai; Chan-Park, Mary B; Wu, Hong; Wang, Dongan; Xu, Rong

    2014-03-01

    A series of high refractive index (RI) ZnS/PVP/PDMAA hydrogel nanocomposites containing ZnS nanoparticles (NPs) were successfully synthesized via a simple ultraviolet-light-initiated free radical co-polymerization method. The average diameter of the ZnS NPs is ∼ 3 nm and the NPs are well dispersed and stabilized in the PVP/PDMAA hydrogel matrix up to a high content of 60 wt.% in the hydrogel nanocomposites. The equilibrium water content of ZnS/PVP/PDMAA hydrogel nanocomposites varied from 82.0 to 66.8 wt.%, while the content of mercaptoethanol-capped ZnS NPs correspondingly varied from 30 to 60 wt.%. The resulting nanocomposites are clear and transparent and their RIs were measured to be as high as 1.58-1.70 and 1.38-1.46 in the dry and hydrated states, respectively, which can be tuned by varying the ZnS NPs content. In vitro cytotoxicity assays suggested that the introduction of ZnS NPs added little cytotoxicity to the PVP/PDMAA hydrogel and all the hydrogel nanocomposites exhibited minimal cytotoxicity towards common cells. The hydrogel nanocomposites implanted in rabbit eyes can be well tolerated over 3 weeks. Hence, the high RI ZnS/PVP/PDMAA hydrogel nanocomposites with adjustable RIs developed in this work might potentially be a candidate material for artificial corneal implants.

  15. New psychoactive substance α-PVP in a traffic accident case.

    Science.gov (United States)

    Rojek, Sebastian; Kula, Karol; Maciów-Głąb, Martyna; Kłys, Małgorzata

    The problems of new psychoactive substances (NPSs), especially related to drivers, constitute an open research area. In this case report, we present a traffic accident case, in which two passengers of five individuals died instantly, while the other three persons survived the accident with minor injuries only. From the blood samples of the driver and the passengers, α-pyrrolidinovalerophenone (α-PVP), an NPS belonging to the category of cathinone derivatives, was disclosed. Therefore, we established a detailed procedure for analysis of α-PVP in blood samples by liquid chromatography-tandem mass spectrometry. After careful validation tests of this method, α-PVP concentration in blood samples from the surviving driver and passengers, and from the two deceased, were measured. The concentrations varied from 20 to 650 ng/mL. Access to detailed information originating from the court files and from explanations provided by the driver and eye witnesses revealed extremely valuable illustrative details addressing the symptoms and pharmacological effects of α-PVP on the human organism, thus contributing to enriching the body of knowledge of α-PVP abuse.

  16. Simple Synthesis and Luminescence Characteristics of PVP-Capped GeO2 Nanoparticles

    Directory of Open Access Journals (Sweden)

    Wei Wu

    2011-01-01

    Full Text Available Polyvinylpyrrolidone (PVP-capped rutile GeO2 nanoparticles were synthesized through a facile hydrothermal process. The obtained nanoparticles were characterized by X-ray diffraction (XRD, transmission electron microscopy (TEM, Fourier transform infrared spectroscopy (FTIR, thermo gravimetric analysis (TGA, and photoluminescence spectroscopy (PL. The capped GeO2 nanoparticles showed significantly enhanced luminescence properties compared with those of the uncapped ones. We attributed this result to the effect of reducing surface defects and enhancing the possibility of electron-hole recombination of the GeO2 nanoparticles by the PVP molecules. PVP-capped GeO2 nanoparticles have potential application in optical and electronic fields.

  17. [The protoskolicidal effect of 1% polyvinylpyrrolidone-iodine (PVP-1) and 2% taurolidine on abdominal hydatidosis].

    Science.gov (United States)

    Ekçı, Baki; Gürol, Yeşim; Aydin, Ismail; Yalniz, Fırat; Ozcan, Murat; Zengın, Kaan

    2010-01-01

    The aim of this study is to determine the efficacy of 1% polyvinylprolidone-iodine (Betadine, PVP-I) and 2% Taurolidine as scolicidal agents for the prevention of abdominal hydatidosis defined as the rupture of the echinococcal cyst spontaneously or traumatically. The study was carried out in fifty mice randomly assigned into 5 treatment groups as following: group with no expose to any scolicidal agent, groups with 1% PVP-I for 2 and 5 minutes; groups with 2 % Taurolidine for 2 minutes, and 5 minutes. PVP-I has found to be effective according to results of staining with the eosin dye in vitro and abdominal hydatidosis in vivo, while Taurolidine was ineffective as a scolicidal agent.

  18. TAILORING OF PORE SIZE IN MESOPOROUS SILICA WITH STEARIC ACID AND PVP

    Institute of Scientific and Technical Information of China (English)

    Haidi Liu; Shufeng Ye; Yunfa Chen

    2005-01-01

    Mesoporous silica was prepared using tetrathoxysilane (TEOS), cetadecyltrimethylammonium bromide (CTAB), aqueous ammonia, acetone and water as silica source, template agent, precipitator and solvent respectively.Stearic acid and polyvinylpyrrolidone (PVP) were employed as additional templates to tailor the pore size in the resultant porous silica. BET, SAXRD and SEM analyses were used to characterize the surface area, pore size, pore structure,pore regularity and morphology of the sample. BET measurement results showed that PVP could increase the surface area but diminish the pore size while stearic acid could decrease the surface area but enlarge the pore size. SAXRD analysis indicated that more additional template introduction gave rise to less order-structured products. All these various results could be attributed to the differently modified CTAB micelles involving stearic acid and PVP addition.

  19. Poly(vinyl pyrrolidone) (PVP) hydrogels study for ophthalmologic area utilization; Estudo de hidrogeis de poli(vinil pirrolidona) (PVP) para utilizacao na area oftalmologica

    Energy Technology Data Exchange (ETDEWEB)

    Amaral, Renata Hage; Rogero, Sizue Ota; Lugao, Ademar Benevolo [Instituto de Pesquisas Energeticas e Nucleares (IPEN), Sao Paulo, SP (Brazil)]. E-mail: farmahage@yahoo.com.br; Cruz, Aurea S. [Instituto Adolfo Lutz, Sao Paulo, SP (Brazil)]. E-mail: aurcruz@ial.sp.gov.br; Sacramento, Rogerio S.; Lima Filho, Acacio A. Souza; Schor, Paulo [Universidade Federal de Sao Paulo (UNIFESP)/Escola Paulista de Medicina, Sao Paulo, SP (Brazil)]. E-mail: rogeroftalmo@yahoo.com.br

    2005-07-01

    Poly (vinyl pyrrolidone) (PVP) hydrogels produced by radiation-induced crosslinking were studied to compose drug delivery system to be used in the eye surface and to manufacture ophthalmic plugs. Some formulations with PVP and poly ethylene glycol (PEG) with different molar mass (300 and 600) were prepared utilizing 0.85% sodium chloride aimed to control the swelling capacity. The obtained hydrogels were characterized by gel fraction and swelling assays. The gel fraction and swelling results indicated no difference in the formulation containing or not NaCl. The gel fraction results varied from 62 to 81% and the swelling degree from 130 to 420%. In vitro assay of cytotoxicity by neutral red uptake method was the first biocompatibility test performed. The results showed no evidence of toxicity in the studied hydrogels. (author)

  20. Transparent conductive PVP/AgNWs films for flexible organic light emitting diodes by spraying method

    Science.gov (United States)

    Hu, Jun-tao; Mei, Wen-juan; Ye, Kang-li; Wei, Qing-qing; Hu, Sheng

    2016-05-01

    In this study, a simple spraying method is used to prepare the transparent conductive films (TCFs) based on Ag nanowires (AgNWs). Polyvinylpyrrolidone (PVP) is introduced to modify the interface of substrate. The transmittance and bending performance are improved by optimizing the number of spraying times and the solution concentration and controlling the annealing time. The spraying times of 20, the concentration of 2 mg/mL and the annealing time of 10 min are chosen to fabricate the PVP/AgNWs films. The transmittance of PVP/AgNWs films is 53.4%—67.9% at 380—780 nm, and the sheet resistance is 30 Ω/□ which is equivalent to that of commercial indium tin oxide (ITO). During cyclic bending tests to 500 cycles with bending radius of 5 mm, the changes of resistivity are negligible. The performance of PVP/AgNW transparent electrodes has little change after being exposed to the normal environment for 1 000 h. The adhesion to polymeric substrate and the ability to endure bending stress in AgNWs network films are both significantly improved by introducing PVP. Spraying method makes AgNWs form a stratified structure on large-area polymer substrates, and the vacuum annealing method is used to weld the AgNWs together at junctions and substrates, which can improve the electrical conductivity. The experimental results indicate that PVP/AgNW transparent electrodes can be used as transparent conductive electrodes in flexible organic light emitting diodes (OLEDs).

  1. Physical stability of solid dispersions with respect to thermodynamic solubility of tadalafil in PVP-VA.

    Science.gov (United States)

    Wlodarski, K; Sawicki, W; Kozyra, A; Tajber, L

    2015-10-01

    The aim of this paper was to evaluate physical stability of solid dispersions in respect to the drug, tadalafil (Td), in vinylpyrrolidone and vinyl acetate block copolymer (PVP-VA). Nine solid dispersions of Td in PVP-VA (Td/PVP-VA) varied in terms of quantitative composition (1:9-9:1, w/w) were successfully produced by spray-drying. Their amorphous nature, supersaturated character and molecular level of mixing (a solid solution structure) were subsequently confirmed using DSC, PXRD, SEM and calculation of Hansen total solubility parameters. Due to thermal degradation of both components before the melting point of Td (302.3°C), an approach based on the drug crystallization from the supersaturated solid dispersion was selected to calculate the solubility of Td in the polymer. Annealing of the Td/PVP-VA solid dispersion (1:1, w/w) at selected temperatures above its Tg resulted in different stable solid dispersions. According to the Gordon-Taylor equation their new Tgs gave the information about the quantitative composition which corresponded to the thermodynamic solubility of Td in PVP-VA at given temperatures of annealing. The obtained relationship was fitted to the exponential function, with the calculated solubility of Td of 20.5% at 25°C. This value was in accordance with the results of hot stage polarizing light microscopy as well as stability tests carried out at 80°C and 0% RH, in which Td solid dispersions containing 10-20% of the drug were the only systems that did not crystallize within two months. A thermal analysis protocol utilizing a fast heating rate was shown to generate Td solubility data complementing the solid dispersion method. The Flory-Huggins model applied for the Td/PVP-VA system yielded the solubility value of 0.1% at 25°C, showing the lack of applicability in this case.

  2. Exploring the synergetic effects of graphene oxide (GO) and polyvinylpyrrodione (PVP) on poly(vinylylidenefluoride) (PVDF) ultrafiltration membrane performance

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Xiaojing [State Key Laboratory of Urban Water Resource and Environment (SKLUWRE), School of Chemical Engineering and Technology, Harbin Institute of Technology 150001 (China); Research Institute of Aerospace Special Materials and Technology, Beijing 100074 (China); Wang, Zhenxing; Quan, Shuai; Xu, Yanchao; Jiang, Zaixing [State Key Laboratory of Urban Water Resource and Environment (SKLUWRE), School of Chemical Engineering and Technology, Harbin Institute of Technology 150001 (China); Shao, Lu, E-mail: odysseynus@hotmail.com [State Key Laboratory of Urban Water Resource and Environment (SKLUWRE), School of Chemical Engineering and Technology, Harbin Institute of Technology 150001 (China)

    2014-10-15

    Graphical abstract: - Highlights: • The synergetic effects of GO and PVP on membrane performance were investigated. • The surface hydrophilicity of membrane was enhanced by the synergistic effects. • The anti-fouling performance was obviously improved in PVDF/GO/PVP membrane. • The optimized performance can be obtained at the stipulated GO and PVP contents. - Abstract: Membrane surface and cross-sectional morphology created during membrane formation is one of the most essential factors determining membrane separation performance. However, the complicated interactions between added nanoparticles and additives influencing membrane morphology and performance during building membrane architectures had been generally neglected. In this study, asymmetric PVDF composite ultrafiltration (UF) membranes containing graphene oxides (GO) were prepared by using N-methyl pyrrolidone (NMP) as solvent and polyvinylpyrrodione (PVP) as the pore forming reagent. In the first time, the effects of mutual interactions between GO and PVP on membranes surface compositions, morphology and performance were investigated in detail. The variation in chemical properties of different membranes and hydrogen bonds in the membrane containing GO and PVP were confirmed by X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy-attenuated total reflectance (FTIR-ATR). Atomic force microscopy (AFM), scanning electron microscopy (SEM), and contact angle (CA) were utilized to clarify the synergetic effects of GO and PVP on morphologies and surface hydrophilicity of membranes. Besides, water flux, bovine serum albumin (BSA) rejection and attenuate coefficient were also determined to investigate filtration performance of various membranes. Compared with pure PVDF membrane, the comprehensive performance of PVDF/GO/PVP membrane has been obviously improved. The surface hydrophilicity and anti-fouling performance were enhanced by the synergistic effects of incorporated GO and

  3. Characterization and physical stability of spray dried solid dispersions of probucol and PVP-K30

    DEFF Research Database (Denmark)

    Thybo, Pia; Pedersen, Betty L; Hovgaard, Lars

    2008-01-01

    The main purpose of this study was to obtain stable, well-characterized solid dispersions (SDs) of amorphous probucol and polyvinylpyrrolidone K-30 (PVP-K30) with improved dissolution rates. A secondary aim was to investigate the flow-through dissolution method for in-vitro dissolution measuremen...

  4. Supercritical CO2-assisted preparation of ibuprofen loaded PEG-PVP complexes

    CSIR Research Space (South Africa)

    Labuschagne, Philip W

    2010-06-01

    Full Text Available Stoichiometric ratios of poly (ethylene glycol) (PEG, Mw = 400) with poly(vinylpyrrolidone) (PVP, Mw = ±3.1 x 104 & Mw = 1.25 x 106 Mw) were prepared from ethanol cast solutions and in supercritical CO2. The complex formation was studied via glass...

  5. Unsupported PVA- and PVP-stabilized Pd nanoparticles as catalyst for nitrite hydrogenation in aqueous phase

    NARCIS (Netherlands)

    Zhao, Y.; Baeza, J.A.; Koteswara Rao, N.; Calvo, L.; Gilarranz, M.A.; Li, Y.D.; Lefferts, L.

    2014-01-01

    Pd colloids stabilized with polyvinyl alcohol (PVA) and polyvinylpyrrolidone (PVP) have been prepared, characterized with TEM, zeta potential measurements, CO chemisorption in aqueous phase, and ATR-IR spectroscopy using CO as a probe molecule, and finally tested for performance in nitrite hydrogena

  6. Novel GQD-PVP-CdS composite with enhanced visible-light-driven photocatalytic properties

    Energy Technology Data Exchange (ETDEWEB)

    Fan, Tao; Li, Yinle; Shen, Jianfeng, E-mail: jfshen@fudan.edu.cn; Ye, Mingxin, E-mail: mxye@fudan.edu.cn

    2016-03-30

    Graphical abstract: - Highlights: • GQD-PVP-CdS composite was prepared for the first time through a facile hydrothermal route. • GQD-PVP-CdS demonstrated outstanding photoactivity under visible light illumination. • GQDs and polymeric material are compounded with CdS nanoparticles simultaneously for the first time. • The addition of GQDs plays pivotal roles in the enhancement of the photoactivity. - Abstract: A facile one-step hydrothermal method to synthesize graphene quantum dots (GQDs)-polyvinyl pyrrolidone (PVP)-CdS nanocomposite was reported. The nanocomposite was thoroughly characterized with X-ray diffraction, transmission electron microscopy, scanning electron microscopy, Fourier-transform infrared spectroscopy, Raman spectroscopy, X-ray photoelectron spectroscopy and ultraviolet–visible spectroscopy. The results confirmed the formation of GQD-PVP-CdS composite with a uniform size (5–10 nm) and a relatively low band gap (E{sub g} = 2.23 eV). Moreover, the as-prepared composite exhibited enhanced photocatalytic activity toward the degradation of organic contaminants, with 92.3% of methyl orange (10 mg/L) removed after 3 hours of visible light illumination. This enhancement in photocatalytic activity was postulated to be attributed to the upconversion property of GQDs and a more efficient charge distribution between GQDs and CdS particles.

  7. Synthesis of PVP-Capped Au-CdSe Hybrid Nanoparticles

    OpenAIRE

    Chili, M. M.; V. S. R. Rajasekhar Pullabhotla; N. Revaprasadu

    2012-01-01

    We report the synthesis of PVP-capped Au-CdSe hybrid nanostructures synthesized using the UV-irradiation method. The high resolution transmission electron microscopy (HRTEM) and powder X-ray diffraction (XRD) studies confirm the presence of the hybrid gold and CdSe nanoparticles.

  8. Standardized comparison of antiseptic efficacy of triclosan, PVP-iodine, octenidine dihydrochloride, polyhexanide and chlorhexidine digluconate.

    Science.gov (United States)

    Koburger, T; Hübner, N-O; Braun, M; Siebert, J; Kramer, A

    2010-08-01

    This study presents a comparative investigation of the antimicrobial efficacy of the antiseptics PVP-iodine, triclosan, chlorhexidine, octenidine and polyhexanide used for pre-surgical antisepsis and antiseptic treatment of skin, wounds and mucous membranes based on internationally accepted standards. MICs and MBCs were determined in accordance with DIN 58940-7 and 58940-8 using Staphylococcus aureus (including methicillin-resistant Staphylococcus aureus), Enterococcus faecalis (including vancomycin-resistant Enterococcus), Streptococcus pneumoniae, Escherichia coli, Pseudomonas aeruginosa, Clostridium perfringens, Haemophilus influenzae and Candida albicans. The microbicidal efficacy was determined in accordance with DIN EN 1040 and 1275 using S. aureus, P. aeruginosa and C. albicans. For chlorhexidine, octenidine and polyhexanide, MIC(48) and MBC(24) ranged from 16 to 32 mg/L. Maximum values for triclosan ranged from 256 to 512 mg/L, with an efficacy gap against P. aeruginosa, while the maximum values of PVP-iodine were 1024 mg/L, with a gap against S. pneumoniae. Comparing the minimal effective concentrations, octenidine was most effective. After 1 min, only octenidine and PVP-iodine fulfil the requirements for antiseptics. Tests under standardized and harmonized conditions help to choose the most efficacious agent. When a prolonged contact time is feasible, ranking of agents would be polyhexanide = octenidine > chlorhexidine > triclosan > PVP-iodine. This is consistent with the recommendations for antisepsis of acute wounds. Polyhexanide seems to be preferable for chronic wounds due to its higher tolerability. If an immediate effect is required, ranking would be octenidine = PVP-iodine> polyhexanide > chlorhexidine > triclosan.

  9. In situ FTIR spectroscopic study of the effect of CO2 sorption on H-bonding in PEG–PVP mixtures

    CSIR Research Space (South Africa)

    Labuschagne, Philip W

    2011-05-01

    Full Text Available A study of the H-bonding between poly(ethylene glycol) (PEG) and polyvinylpyrrolidone (PVP) in the presence of supercritical carbon dioxide at various temperatures, pressures, different M(w) of PEG and PVP and different PEG/PVP ratios is presented...

  10. Solid-state characterization and dissolution properties of meloxicam-moringa coagulant-PVP ternary solid dispersions.

    Science.gov (United States)

    Noolkar, Suhail B; Jadhav, Namdeo R; Bhende, Santosh A; Killedar, Suresh G

    2013-06-01

    The effect of ternary solid dispersions of poor water-soluble NSAID meloxicam with moringa coagulant (obtained by salt extraction of moringa seeds) and polyvinylpyrrolidone on the in vitro dissolution properties has been investigated. Binary (meloxicam-moringa and meloxicam-polyvinylpyrrolidone (PVP)) and ternary (meloxicam-moringa-PVP) systems were prepared by physical kneading and ball milling and characterized by Fourier transform infrared spectroscopy, differential scanning calorimetry, and X-ray diffractometry. The in vitro dissolution behavior of meloxicam from the different products was evaluated by means of United States Pharmacopeia type II dissolution apparatus. The results of solid-state studies indicated the presence of strong interactions between meloxicam, moringa, and PVP which were of totally amorphous nature. All ternary combinations were significantly more effective than the corresponding binary systems in improving the dissolution rate of meloxicam. The best performance in this respect was given by the ternary combination employing meloxicam-moringa-PVP ratio of [1:(3:1)] prepared by ball milling, with about six times increase in percent dissolution rate, whereas meloxicam-moringa (1:3) and meloxicam-PVP (1:4) prepared by ball milling improved dissolution of meloxicam by almost 3- and 2.5-folds, respectively. The achieved excellent dissolution enhancement of meloxicam in the ternary systems was attributed to the combined effects of impartation of hydrophilic characteristic by PVP, as well as to the synergistic interaction between moringa and PVP.

  11. The influence of PVP incorporation on moisture-induced surface crystallization of amorphous spray-dried lactose particles.

    Science.gov (United States)

    Mahlin, Denny; Berggren, Jonas; Gelius, Ulrik; Engström, Sven; Alderborn, Göran

    2006-09-14

    We have recently shown that atomic force microscopy (AFM) may be an appropriate method for characterisation of the re-crystallization of amorphous particles. In this study, spray-dried composite particles consisting of lactose and polyvinyl pyrrolidon (PVP) were characterised by AFM and electron spectroscopy for chemical analysis (ESCA), and their response on increasing the relative humidity (RH) was investigated. The PVP content in the particles used was 0, 5 or 25 wt.% of either PVP K17 or PVP K90. All composite particles were found to be enriched with PVP at the surface. The incorporation of PVP in the particles influenced the way the particles responded to an increase in RH. The specific RH interval in which the surface of the particles smoothened and the RH where crystallization could be detected, increased with an increase in the amount and molecular weight of the PVP in the particles. The crystallization kinetics of single particles was analysed with AFM and by utilising the JMAK equation. The rate constant for this transformation increased in an exponential manner with increasing RH. Furthermore, above the RH needed for the crystallization to occur, the exponential increase in the crystallization rate was larger for particles with higher polymer content which indicates that the stabilising effect decreases as the water content in the particles becomes higher. In this study we report a method for determination of crystallization kinetics on single composite particles, which is valuable when evaluating the effect of stabilisers in amorphous powders.

  12. Ion Transport and Discharge Characteristics of Polymer Blend (PVP/PVA) Electrolyte Films Doped with Potassium Iodide

    Science.gov (United States)

    Umadevi, C.; Mohan, K. R.; Achari, V. B. S.; Sharma, A. K.; Rao, V. V. R. N.

    2010-12-01

    Solid polymer blend electrolyte films based on PVP/PVA complexed with KI were prepared by the solution cast technique. Various experimental techniques such as electrical conductivity and transport number measurement were used to characterize the polymer electrolyte films. Electrochemical cells with the polymer electrolytes (PVP+PVA+KI) were fabricated in the configuration K/(PVP+PVA+KI)/ (I2+C+electrode). The discharge characteristics of the cells were studied under a constant load of 100 KΩ. The open-circuit voltage, short-circuit current and discharge time for the plateau region are measured. Several other cell parameters were evaluated and are reported.

  13. Fabrication of CH3NH3PbI3/PVP Composite Fibers via Electrospinning and Deposition

    Directory of Open Access Journals (Sweden)

    Li-Min Chao

    2015-08-01

    Full Text Available In our study, one-dimensional PbI2/polyvinylpyrrolidone (PVP composition fibers have been prepared by using PbI2 and PVP as precursors dissolved in N,N-dimethylformamide via a electrospinning process. Dipping the fibers into CH3NH3I solution changed its color, indicating the formation of CH3NH3PbI3, to obtain CH3NH3PbI3/PVP composite fibers. The structure, morphology and composition of the all as-prepared fibers were characterized by using X-ray diffraction and scanning electron microscopy.

  14. Fabrication of CH3NH3PbI3/PVP Composite Fibers via Electrospinning and Deposition

    Science.gov (United States)

    Chao, Li-Min; Tai, Ting-Yu; Chen, Yueh-Ying; Lin, Pei-Ying; Fu, Yaw-Shyan

    2015-01-01

    In our study, one-dimensional PbI2/polyvinylpyrrolidone (PVP) composition fibers have been prepared by using PbI2 and PVP as precursors dissolved in N,N-dimethylformamide via a electrospinning process. Dipping the fibers into CH3NH3I solution changed its color, indicating the formation of CH3NH3PbI3, to obtain CH3NH3PbI3/PVP composite fibers. The structure, morphology and composition of the all as-prepared fibers were characterized by using X-ray diffraction and scanning electron microscopy. PMID:28793517

  15. Selective formation of tetrahedral Pt nanocrystals from K2PtCl6/PVP

    Institute of Scientific and Technical Information of China (English)

    YU Yingtao; XU Boqing

    2003-01-01

    Tetrahedral platinum (Pt) nanocrystals (3-8 nm) are synthesized in high selectivity (ca. 80%) from hydrogen reduction of aqueous K2PtCl6 by using polyvinylpyrrolidone (PVP: Mw≈360000) as a protector. Morphology (TEM) measurements of the metal colloids and UV-Vis absorption of the colloidal solution are employed to monitor the tetrahedron formation during the syntheses with varying K2PtCl6/PVP ratios. The results clearly show a two-stage process for the selective formation of tetrahedral nanocrystals. Rapid nucleation and crystal formation at the early stage result in round-like crystallites and the external facet evolution in thereafter slow crystal growth leads selectively to the formation of the tetrahedrons.

  16. Polyvinylpyrrolidone (PVP)-capped Pt Nanocubes with Superior Peroxidase-like Activity

    Energy Technology Data Exchange (ETDEWEB)

    Ye, Haihang; Liu, Y.; chhabra, ashima; lilla, emily; xia, xiaohu

    2017-01-01

    Peroxidase mimics of inorganic nanoparticles are expected to circumvent the inherent issues of natural peroxidases, providing enhanced performance in important applications such as diagnosis and imaging. Despite the report of a variety of peroxidase mimics in the past decade, very limited progress has been made on improving their catalytic efficiency. The catalytic efficiencies of most previously reported mimics are only up to one order of magnitude higher than those of natural peroxidases. In this work, we demonstrate a type of highly efficient peroxidase mimic – polyvinylpyrrolidone (PVP)-capped Pt nanocubes of sub-10 nm in size. These PVP-capped Pt cubes are ~200-fold more active than the natural counterparts and exhibit a record-high specific catalytic efficiency. In addition to the superior efficiency, the new mimic shows several other promising features, including excellent stabilities, well-controlled uniformity in both size and shape, controllable sizes, and facile and scalable production.

  17. PVP-Stabilized Palladium Nanoparticles in Silica as Effective Catalysts for Hydrogenation Reactions

    Directory of Open Access Journals (Sweden)

    Caroline Pires Ruas

    2013-01-01

    Full Text Available Palladium nanoparticles stabilized by poly (N-vinyl-2-pyrrolidone (PVP can be synthesized by corresponding Pd(acac2 (acac = acetylacetonate as precursor in methanol at 80°C for 2 h followed by reduction with NaBH4 and immobilized onto SiO2 prepared by sol-gel process under acidic conditions (HF or HCl. The PVP/Pd molar ratio is set to 6. The effect of the sol-gel catalyst on the silica morphology and texture and on Pd(0 content was investigated. The catalysts prepared (ca. 2% Pd(0/SiO2/HF and ca. 0,3% Pd(0/SiO2/HCl were characterized by TEM, FAAS, and SEM-EDS. Palladium nanoparticles supported in silica with a size 6.6 ± 1.4 nm were obtained. The catalytic activity was tested in hydrogenation of alkenes.

  18. Controlling growth of ZnO rods by polyvinylpyrrolidone (PVP) and their optical properties

    Science.gov (United States)

    Wei, S. F.; Lian, J. S.; Jiang, Q.

    2009-05-01

    ZnO rods with different morphologies were synthesized through a wet chemical method by addition of polyvinylpyrrolidone (PVP). By adjusting the concentration of the additive in the growth solution, we can control the diameter, ratio of length to diameter and density of ZnO rods. FESEM images showed that the rods in nanoscale could be obtained at the polyvinylpyrrolidone concentration of 1.0 mM. Meanwhile, the resonant Raman scattering and photoluminescence spectra showed that the crystalline quality and the optical property of ZnO rods were improved through moderate addition of polyvinylpyrrolidone (concentration of 1.0 mM) in the growth solution. In addition, the possible mechanism of the PVP effect on the growth of ZnO rods was discussed based on the FT-IR spectra.

  19. Experimental design of mixture applied to study PVP hydrogels properties crosslinked by ionizing radiation

    Energy Technology Data Exchange (ETDEWEB)

    Alcantara, Mara Tania S.; Lugao, Ademar B., E-mail: maratalcantara@uol.com.b [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Taqueda, Maria Elena S. [Universidade de Sao Paulo (USP), SP (Brazil). Escola Politecnica. Dept. de Engenharia Quimica

    2009-07-01

    Hydrogels are three dimensional hydrophilic crosslinked polymeric networks that have capacity to swell by absorbing water or biological fluids without dissolve. Hydrogels have been widely used in different application fields from agriculture, industry and in biomedicine. The properties of a hydrogel are extremely important in selecting which materials are suitable for a specific application. So mixtures can offer hydrogels with different properties to different applications. The PVP hydrogels were prepared by gamma radiation of an aqueous polymer solution and crosslinked by gamma ray, an effective and simple method for hydrogel formation that offers some advantages over the other techniques. In this work, a mixture experimental design was used to study the relationship between polymer cross-linking and swelling properties of PVP hydrogels with PEG as plasticizer and agar as gellifier. The gel fraction was measured for every mixture specified for the experiment D-optimal designs. (author)

  20. Effect of Polymers (PEG and PVP on Sol-Gel Synthesis of Microsized Zinc Oxide

    Directory of Open Access Journals (Sweden)

    Thilagavathi Thirugnanam

    2013-01-01

    Full Text Available Fibers irregular and seed-like microcrystalline ZnO were synthesized by using a cost-effective and low temperature aqueous sol-gel method. Various polymers, namely, polyethylene glycol 6000 (PEG 6000 and polyvinyl pyrrolidone (PVP, were used as structure directing agents. The samples were characterized by X-ray diffraction (XRD, Fourier transform infrared spectroscopy (FTIR, and scanning electron microscopy (SEM. The X-ray diffraction pattern revealed the formation of phase-pure ZnO micropowders. It is observed that the polymers play an important role in modifying the surface morphology and the size of the crystallites. A compact granular morphology is observed for the ZnO samples without polymer. The samples exhibit microparticles of size 100 nm for PVP and for PEG-mediated growth, whereas microporous corrugated morphology is observed for added PEG-mediated micropowder. FTIR study is used to confirm the structural modifications occurring in the polymers.

  1. Thermal, vibrational, and dielectric studies on PVP/LiBF4+ionic liquid [EMIM][BF4]-based polymer electrolyte films

    Science.gov (United States)

    Saroj, A. L.; Singh, R. K.; Chandra, S.

    2014-07-01

    Free-standing polymer electrolyte membranes based on poly(vinyl) pyrrolidone (PVP)/salt(LiBF4) having different amounts of ionic liquid (IL) [EMIM][BF4] were prepared and characterized by thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), Fourier transform infrared (FT-IR) spectroscopy, and alternating current (AC) impedance spectroscopic techniques. The DSC results show a shift in Tm of PVP with salt/or IL content. TGA and DTGA (first derivative of TGA) results give evidence of the presence of uncomplexed PVP, PVP/salt, and PVP/IL complexes. Signatures of these entities are also present in the dielectric spectra. Complexation of PVP with salt and IL has been confirmed by FT-IR analysis. Electrical conductivity as a function of temperature has been studied for PVP/LiBF4/IL [EMIM][BF4]. Role of IL in changing phase transition, conductivity, and dielectric relaxation frequency has been discussed.

  2. Amorphous solid dispersions of sulfonamide/soluplus® and sulfonamide/PVP prepared by ball milling

    OpenAIRE

    Healy, Anne,

    2013-01-01

    PUBLISHED The aim of this paper is to investigate the physicochemical properties of binary amorphous dispersions of poorly soluble sulfonamide/polymeric excipient prepared by ball milling. The sulfonamides selected were sulfathiazole (STZ), sulfadimidine (SDM), sulfamerazine (SMZ) and sulfadiazine (SDZ). The excipients were polyvinylpyrrolidone (PVP) and polyvinyl caprolactam-polyvinyl acetate-polyethylene glycol graft co-polymer, commercially known as Soluplus®. Co-milled systems were cha...

  3. Thermal Processing of PVP- and HPMC-Based Amorphous Solid Dispersions.

    Science.gov (United States)

    LaFountaine, Justin S; Prasad, Leena Kumari; Brough, Chris; Miller, Dave A; McGinity, James W; Williams, Robert O

    2016-02-01

    Thermal processing technologies continue to gain interest in pharmaceutical manufacturing. However, the types and grades of polymers that can be utilized in common thermal processing technologies, such as hot-melt extrusion (HME), are often limited by thermal or rheological factors. The objectives of the present study were to compare and contrast two thermal processing methods, HME and KinetiSol® Dispersing (KSD), and investigate the influence of polymer type, polymer molecular weight, and drug loading on the ability to produce amorphous solid dispersions (ASDs) containing the model compound griseofulvin (GRIS). Dispersions were analyzed by a variety of imaging, solid-state, thermal, and solution-state techniques. Dispersions were prepared by both HME and KSD using polyvinylpyrrolidone (PVP) K17 or hydroxypropyl methylcellulose (HPMC) E5. Dispersions were only prepared by KSD using higher molecular weight grades of HPMC and PVP, as these could not be extruded under the conditions selected. Powder X-ray diffraction (PXRD) analysis showed that dispersions prepared by HME were amorphous at 10% and 20% drug load; however, it showed significant crystallinity at 40% drug load. PXRD analysis of KSD samples showed all formulations and drug loads to be amorphous with the exception of trace crystallinity seen in PVP K17 and PVP K30 samples at 40% drug load. These results were further supported by other analytical techniques. KSD produced amorphous dispersions at higher drug loads than could be prepared by HME, as well as with higher molecular weight polymers that were not processable by HME, due to its higher rate of shear and torque output.

  4. Thermodynamic aspects of polymer–surfactant interactions: Gemini (16-5-16)-PVP-water system

    OpenAIRE

    2016-01-01

    The interaction between polyvinylpyrrolidone (PVP) and gemini surfactant (16-5-16) in aqueous solution has been analyzed using conductometry. From conductivity data the critical aggregation concentration (cac), critical micelle concentration (cmc), the effective degree of counter-ion binding (β) at different temperatures were obtained. The thermodynamic parameters, i.e., Gibbs energy of aggregation and micellization, standard enthalpy of aggregation, and standard entropy of aggregation of sur...

  5. Pharmacological effects of methamphetamine and alpha-PVP vapor and injection.

    Science.gov (United States)

    Marusich, Julie A; Lefever, Timothy W; Blough, Bruce E; Thomas, Brian F; Wiley, Jenny L

    2016-07-01

    Vaporizing drugs in e-cigarettes is becoming a common method of administration for synthetic cathinones and classical stimulants. Heating during vaporization can expose the user to a cocktail of parent compound and thermolytic degradants, which could lead to different toxicological and pharmacological effects compared to ingesting the parent compound alone via injection or nasal inhalation. This study examined the in vivo toxicological and pharmacological effects of vaporized and injected methamphetamine (METH) and α-pyrrolidinopentiophenone (α-PVP). Male and female ICR mice were administered METH or α-PVP through vapor or i.p. injection. Dose-effect curves were determined for locomotor activity and a functional observational battery (FOB). METH and α-PVP vapor were also evaluated for place preference in male mice. Vapor exposure and injection led to more similarities than differences in toxicological and pharmacological effects. In the FOB, both routes of administration produced typical stimulant effects, and injection also increased some bizarre behaviors (e.g. licking, teeth chattering, darting). Both METH and α-PVP vapor exposure produced conditioned place preference. The two routes of administration had comparable efficacy in locomotor activation, with vapor producing longer lasting effects than injection. Females showed greater METH-induced locomotor activity, and greater incidence of a few somatic signs in the FOB than males. These results explore the toxicology of stimulant vapor inhalation in mice using an e-cigarette device. Despite the current technological and methodological difficulties, studying drug vapor promises to allow determination of toxicological effects of thermolytic products and flavor additives.

  6. Effects of PVP on the preparation and growth mechanism of monodispersed Ni nanoparticles

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Monodispersed Ni nanoparticles were successfully prepared by chemical reduction with hydrazine hydrate in ethylene glycol.The effect of the amount of polyvinylpyrrolidone (PVP-K30) on the preparation of Ni nanoparticles was investigated.X-ray diffraction (XRD),transmission electron microscopy (TEM),and high resolution transmission electron microscopy (HRTEM) were employed to characterize the nickel particles are spherical in shape and are not agglomerated.A possible extensive mechanism of nickel nanoparticle formation has been suggested.

  7. Comparative study of gum arabic and PVP as stabilizing agents for synthesis of gold nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Andressa A.; Leal, Jessica; Geraldes, Adriana N.; Lugao, Ademar B., E-mail: andressa_alvess@yahoo.com.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2015-07-01

    Use Colloidal metallic nanoparticles such as gold nanoparticles have received a great attention, due in part to their specific properties and potential applications. Control of size and uniformity of nanoparticles is important to prevent aggregation. High-molecular-weight polymers were used as stabilizer agents. Natural polymers, such as gum Arabic, are used as stabilizer because of capping nanoparticles behavior and present advantages such as solubility, non- toxicity and its compatibility for pharmaceutical and biomedical applications. Previous studies showed that the hydrophilic group of Poly(vinyl pyrrolidone) (PVP) caused repulsion on gold nanoparticles surface because steric interactions with polymer, for this reason this kind of polymers could be used as stabilizer agent. The aim of this work is to study the synthesis and stabilization of gold nanoparticles with PVP and gum Arabic using gamma radiation. The results obtained by samples analysis using UV-Visible showed that the gamma irradiation doses influenced the nanoparticles formation by PVP but that is not the case with the GA, because for smaller quantity of Arabic gum in different doses produced and stabilized nanoparticles. The samples were observed for 20 days and showed stability. We have obtained preliminary results showed that the use of radiation is applicable to the formation of gold nanoparticles. (author)

  8. Production of Prednisolone by Pseudomonas oleovorans Cells Incorporated Into PVP/PEO Radiation Crosslinked Hydrogels

    Directory of Open Access Journals (Sweden)

    Abeer Abd El-Hady

    2004-01-01

    Full Text Available In order to rise the yield of prednisolone from hydrocortisone, the Pseudomonas oleovorans cells were entrapped into radiation crosslinked poly (vinyl pyrrolidone/poly(ethylene oxide (PVP/PEO hydrogel of different gel contents. The factors affecting the gel content and swelling behavior of the polymeric gel, such as polymer composition, polymer blend concentration, and irradiation doses, were investigated. The formation of gels having a good strength with the ability to retain a desirable amount of water in their three-dimensional network can be achieved by using PVP/PEO copolymer of composition (90:10 and concentration of 15% prepared at 20 kGy irradiation dose. At these conditions the prepared hydrogel is considered the most favorable one that gave the highest hydrocortisone bioconversion and prednisolone yield, 81% and 62.8%, respectively. The improvement of prednisolone yield was also achieved by increasing substrate concentration. Maximum hydrocortisone bioconversion (86.44 was obtained at 18 hours by using substrate concentration of 30 mg. Reusability of immobilized Pseudomonas oleovorans entrapped into PVP/PEO copolymer hydrogel was studied. The results indicated that the transformation capacity of hydrocortisone to prednisolone highly increased by the repeated use of copolymer for 4 times. This was accompanied by an increase in prednisolone yield to 89% and the bioconversion of hydrocortisone was 98.8%.

  9. Synthesis of antibacterial film CTS/PVP/TiO2/Ag for drinking water system.

    Science.gov (United States)

    Zhang, Liang; Bai, Xue; Tian, Hua; Zhong, Lvling; Ma, Cailian; Zhou, Yuanzhen; Chen, Shuangli; Li, Dongliang

    2012-08-01

    A CTS/PVP/TiO2/Ag functional film was prepared as an antibacterial composite used in storing drinking water. The orthogonal experiment showed that the optimal conditions for preparing membranes with best antibacterial activity and tensile strength are c(AgNO3)=0.08%, c(TiO2)=0.20%, c(CTS)=2.25%, and c(PVP)=3.00%. The FT-IR spectrum implies that hydrogen bands are formed between acetyl in PVP and hydroxyl in CTS molecule, and -NH and -OH of CTS have some interactions with sliver nano-particles (nano-Ags) which were reduced in situ. The SEM images show that the TiO2 particles are displayed on the surface and embedded in the film. And nano-Ags are further proved through XRD and SEM images. The DSC curves show that the film has a favorable compatibility and heat stability. In application study, it is proved that this film has sustainable antibacterial activity and is safe in use.

  10. Characterization and physical stability of tolfenamic acid-PVP K30 solid dispersions.

    Science.gov (United States)

    Thybo, Pia; Kristensen, Jakob; Hovgaard, Lars

    2007-01-01

    Obtaining a stable formulation with high bioavailability of a poorly water-soluble drug often presents a challenge to the formulation scientist. Transformation of the drug into its more soluble high-energy amorphous form is one method used for improving the dissolution rate of such compounds. The present study uses the spray-drying technique for preparation of solid dispersions (SDs) of tolfenamic acid (TA) and polyvinylpyrrolidone K-30 (PVP). The SDs and TA in the form of a spray-dried powder were initially characterized and compared with a physical mixture and starting materials. Stability of the SDs was monitored over 12 weeks at 25 degrees C and 60% RH. XRPD studies revealed changes in solid state during the formation of the SDs and indicated the presence of TA in the amorphous state. FTIR, together with TGA, suggested molecular interactions (hydrogen-bonding) in the SDs. Dissolution studies proved an increase in the dissolution rate of TA from all SDs. The SDs with higher content of PVP retained TA in the amorphous state throughout the stability study. However, SDs with lower content showed recrystallization of TA after 1 week. Thus, this study reveals the possibility of preparing stable SDs of amorphous TA in PVP with improved dissolution rate.

  11. Network structure studies on γ-irradiated collagen-PVP superabsorbent hydrogels

    Science.gov (United States)

    Demeter, Maria; Virgolici, Marian; Vancea, Catalin; Scarisoreanu, Anca; Kaya, Madalina Georgiana Albu; Meltzer, Viorica

    2017-02-01

    Collagen-polyvinylpyrrolidone (PVP) superabsorbent hydrogels were synthesized by γ- irradiation in the absence of oxygen, using high molecular weight PVP and acidic collagen Type I. Sol-gel analysis and swelling experiments were performed in order to determine the gel fraction, network parameters, the yield of cross-linking, respectively scission, as well as to establish the diffusion characteristics of water. Rheological experiments and characterization of the chemical structure before and after irradiation were conducted in order to evaluate the gel character and its stability upon irradiation. The relationship between these parameters and radiation dose was also established. Gel fraction reached up to 90%, and the p0/q0 ratio (degradation vs. cross-linking ratio) shows a negligible degradation process. The collagen-PVP hydrogels present swelling in the range 1000-2000%, the diffusion exponent (n) was found to be between 0.59 and 0.68. The network parameters as the molecular weights between two successive cross - links (Mc), the cross-linking density (ϑe) and the mesh size (ξ) are ranged between 3.39-8.08×104g·mol-1, 1.24-2.95×10-5mol·cm-3, respectively 75-134 nm.

  12. Photo physical studies of PVP arrested ZnS quantum dots

    Science.gov (United States)

    Shahi, Ashutosh Kumar; Pandey, Bishnu Kumar; Singh, Bheeshma Pratap; Gupta, Bipin Kumar; Singh, Sukhvir; Gopal, Ram

    2017-03-01

    Monodispersed polyvinylpyrrolidone (PVP) arrested ZnS quantum dots (QDs) having diameter in range 2-5 nm are synthesized by a colloidal precipitation method using PVP as the stabilizing agent. X-ray diffraction (XRD), transmission electron microscopy (TEM), high resolution transmission electron microscopy (HRTEM), selective area electron diffraction (SAED) and Fourier transform infrared (FT-IR) spectroscopy are probed to investigate the structural information. The optical properties are studied using diffuse UV-visible reflectance and photoluminescence (PL) spectroscopy techniques. TEM images as well as XRD reflection peak broadening indicate the nanometer size particles formation with cubic (sphalerite) phase within the polymer matrix. Optical absorbance studies reveal an excitonic peak at around 310 nm dictates the effect of quantum confinement effect in the ZnS QDs. PL emission spectra for ZnS QDs in PVP exhibit four emission peaks at 382 nm, 414 nm, 480 nm and 527 nm are observed. These excitonic emissions from ZnS QDs are caused by the interstitial sulfur/Zn vacancies and surface states.

  13. Modifying excitation light dose of novel photosensitizer PVP-Hypericin for photodynamic diagnosis and therapy.

    Science.gov (United States)

    Penjweini, Rozhin; Loew, Hans G; Eisenbauer, Maria; Kratky, Karl W

    2013-03-05

    Conventional photodynamic diagnosis (PDD) and therapy (PDT) makes use of photosensitizers that are excited by continuous light irradiation of specific wavelengths. In the case of PDT, the overdose of continuous excitation may lead to an expansion of necrosis in cancer cells or morbidity in healthy surroundings. The present study involves 5-h fluorescence imaging of living human lung epithelial carcinoma cells (A549) in the presence of a novel photosensitizer, PVP-Hypericin (PVP: polyvinylpyrrolidone) to optimize the excitation light doses for PDD and PDT. A number of time-lapse imaging experiments were performed using a low-power blue LED operating in either continuous or pulsed mode. The irradiances I(*) were 1.59, 6.34 and 14.27mW/cm(2), the pulse lengths L being 0.127, 1.29, 13, 54.5, 131 and 60,000ms. Then, the relation between irradiance, various exposure times, photobleaching and phototoxicity of PVP-Hyperycin was investigated. Results showed a nonlinear relationship between the amounts of excitation dose, cell viability and toxicity. For all experimental I(*), minimal phototoxicity and photobleaching was detected when cells were exposed to brief pulses of light (L⩽13ms). On the other hand, pulsed excitation with I(*)=14.27mW/cm(2) and L=131ms induced high percentages of apoptosis comparable to the long exposures of L=60,000ms and the continuous excitation. Thus, replacement of continuous excitation by a pulsed method seems applicable for PDT.

  14. Hydrophobic interactions increase attachment of gum Arabic- and PVP-coated Ag nanoparticles to hydrophobic surfaces.

    Science.gov (United States)

    Song, Jee Eun; Phenrat, Tanapon; Marinakos, Stella; Xiao, Yao; Liu, Jie; Wiesner, Mark R; Tilton, Robert D; Lowry, Gregory V

    2011-07-15

    A fundamental understanding of attachment of surface-coated nanoparticles (NPs) is essential to predict the distribution and potential risks of NPs in the environment. Column deposition studies were used to examine the effect of surface-coating hydrophobicity on NP attachment to collector surfaces in mixtures with varying ratios of octadecylichlorosilane (OTS)-coated (hydrophobic) glass beads and clean silica (hydrophilic) glass beads. Silver nanoparticles (AgNPs) coated with organic coatings of varying hydrophobicity, including citrate, polyvinylpyrrolidone (PVP), and gum arabic (GA), were used. The attachment efficiencies of GA and PVP AgNPs increased by 2- and 4-fold, respectively, for OTS-coated glass beads compared to clean glass beads. Citrate AgNPs showed no substantial change in attachment efficiency for hydrophobic compared to hydrophilic surfaces. The attachment efficiency of PVP-, GA-, and citrate-coated AgNPs to hydrophobic collector surfaces correlated with the relative hydrophobicity of the coatings. The differences in the observed attachment efficiencies among AgNPs could not be explained by classical DLVO, suggesting that hydrophobic interactions between AgNPs and OTS-coated glass beads were responsible for the increase in attachment of surface-coated AgNPs with greater hydrophobicity. This study indicates that the overall attachment efficiency of AgNPs will be influenced by the hydrophobicity of the NP coating and the fraction of hydrophobic surfaces in the environment.

  15. Preparation, Characterization and Stability Studies of Glassy Solid Dispersions of Indomethacin using PVP and Isomalt as carriers

    OpenAIRE

    2012-01-01

    Objective(s) The purpose of the present study was to use the solid dispersion (SD) technique to improve the dissolution rates of indomethacin (IMC). Materials and Methods IMC solid dispersions in PVP K30 and isomalt (GALEN IQ 990) were prepared using the solvent evaporation technique and a hot melt method in weight ratios of 2, 10 and 30% (IMC:PVP). Solid dispersions and physical mixtures were characterized by X-ray powder diffraction (XRPD), differential scanning calorimetry (DSC) and dissol...

  16. Preparation and characterization of celecoxib solid dispersions; comparison of poloxamer-188 and PVP-K30 as carriers

    Directory of Open Access Journals (Sweden)

    Alireza Homayouni

    2014-05-01

    Full Text Available Objective(s:Solid dispersion formulation is the most promising strategy to improve oral bioavailability of poorly water soluble drugs. The aim of this study was to compare the effect of polyvinylpyrrolidone K30 (PVP and poloxamer-188 (PLX as carrier in solid dispersion formulations of celecoxib (CLX. Materials and Methods: Solid dispersions of CLX:PVP or CLX:PLX were prepared at different ratios (2:1, 1:1, 1:2, 1:4, 1:6 by solvent evaporation and melting methods, respectively. The characterization of samples was performed using differential scanning calorimetery (DSC, X-Ray powder diffraction (XRPD and Fourier transform infrared spectroscopy (FT-IR. The Gordon-Taylor equation was used to estimate the Tg of solid dispersion systems and the possibility of the interaction between CLX and PVP. Also, the dissolution rate of all samples was determined. Results: DSC and XRPD analyses confirmed the presence of amorphous state of drug in solid dispersion systems. FT-IR studies showed CLX could participate in hydrogen bonding with PVP whilst no specific interaction between CLX and PLX was observed. Both PVP and PLX enhanced the dissolution rate of drug in solid dispersion samples. The dissolution rate was dependent on the ratio of drug: carrier. Interestingly, the solid dispersion samples of PLX at 2:1 and 1:1 drug: carrier showed slower dissolution rate than pure CLX, whilst these results were not observed for PVP. Conclusion: The effect of PVP on dissolution rate enhancement was more pronounced compared to the other carrier. Having a higher Tg and more effect on dissolution rate, PVP could be considered as a more suitable carrier compared to PLX in solid dispersion formulation of CLX.

  17. Solid-State Characterization and Dissolution Properties of Meloxicam–Moringa Coagulant–PVP Ternary Solid Dispersions

    OpenAIRE

    Noolkar, Suhail B.; Jadhav, Namdeo R; Bhende, Santosh A.; Suresh G. Killedar

    2013-01-01

    The effect of ternary solid dispersions of poor water-soluble NSAID meloxicam with moringa coagulant (obtained by salt extraction of moringa seeds) and polyvinylpyrrolidone on the in vitro dissolution properties has been investigated. Binary (meloxicam–moringa and meloxicam–polyvinylpyrrolidone (PVP)) and ternary (meloxicam–moringa–PVP) systems were prepared by physical kneading and ball milling and characterized by Fourier transform infrared spectroscopy, differential scanning calorimetry, a...

  18. Exploring the synergetic effects of graphene oxide (GO) and polyvinylpyrrodione (PVP) on poly(vinylylidenefluoride) (PVDF) ultrafiltration membrane performance

    Science.gov (United States)

    Chang, Xiaojing; Wang, Zhenxing; Quan, Shuai; Xu, Yanchao; Jiang, Zaixing; Shao, Lu

    2014-10-01

    Membrane surface and cross-sectional morphology created during membrane formation is one of the most essential factors determining membrane separation performance. However, the complicated interactions between added nanoparticles and additives influencing membrane morphology and performance during building membrane architectures had been generally neglected. In this study, asymmetric PVDF composite ultrafiltration (UF) membranes containing graphene oxides (GO) were prepared by using N-methyl pyrrolidone (NMP) as solvent and polyvinylpyrrodione (PVP) as the pore forming reagent. In the first time, the effects of mutual interactions between GO and PVP on membranes surface compositions, morphology and performance were investigated in detail. The variation in chemical properties of different membranes and hydrogen bonds in the membrane containing GO and PVP were confirmed by X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy-attenuated total reflectance (FTIR-ATR). Atomic force microscopy (AFM), scanning electron microscopy (SEM), and contact angle (CA) were utilized to clarify the synergetic effects of GO and PVP on morphologies and surface hydrophilicity of membranes. Besides, water flux, bovine serum albumin (BSA) rejection and attenuate coefficient were also determined to investigate filtration performance of various membranes. Compared with pure PVDF membrane, the comprehensive performance of PVDF/GO/PVP membrane has been obviously improved. The surface hydrophilicity and anti-fouling performance were enhanced by the synergistic effects of incorporated GO and PVP. When the PVP content was 0.25 wt.% and the GO content was 0.5 wt.%, the optimized performance can be obtained due to the formation of hydrogen bonds between GO and PVP.

  19. A Novel Research on Behavior of Zinc Ferrite Nanoparticles in Different Concentration of Poly(vinyl pyrrolidone (PVP

    Directory of Open Access Journals (Sweden)

    Halimah Mohamed Kamari

    2014-04-01

    Full Text Available Zinc ferrite nanocrystals were prepared from an aqueous solution containing metal nitrates and various of concentrations of poly(vinyl pyrrolidone (PVP, i.e., 0, 15, 40, and 55 g/L, as a capping agent. To stabilize the particles, they were thermally treated at 873 K, as an optimum calcination temperature. The behaviors of the polymeric precursor were analyzed by use of simultaneous thermo-gravimetry (TG and derivative thermo-gravimetry analyses (DTG. The presence of the crystalline phase in each sample was confirmed by X-ray diffraction (XRD analysis. The average particle size and the morphology of the nanoparticles were determined by transmission electron microscopy (TEM, and these parameters were found to differ at various concentrations of PVP. Fourier transform infrared spectroscopy (FT-IR confirmed the presence of metal oxide bands for all the PVP concentrations and confirmed the absence of organic bands for PVP concentrations less than 55 g/L. Measurements of the magnetization value of the zinc ferrite nanoparticles were obtained at room temperature by using a vibrating sample magnetometer (VSM, which showed that, in the absence of PVP, the sample exhibited a paramagnetic behavior while, in the presence of PVP, samples have a super-paramagnetic behavior.

  20. A novel catalyst containing palladium nanoparticles supported on PVP composite nanofiber films: Synthesis, characterization and efficient catalysis

    Science.gov (United States)

    Guo, Liping; Bai, Jie; Li, Chunping; Meng, Qingrun; Liang, Haiou; Sun, Weiyan; Li, Hongqiang; Liu, Huan

    2013-10-01

    This paper studied the preparation of Pd nanoparticles/PVP composite nanofiber membranes catalyst. In the experiment, reductant was ethanol and PVP (polyvinyl pyrrolidone) served as the protecting agent as well as supporter of palladium nanoparticles. Pd nanoparticles/PVP sol was examined by UV-vis absorbance spectra (UV-vis); Pd NPs/PVP nanofibers were characterized by scanning electron microscope (SEM) and transmission electron microscope (TEM). The Pd NPs/PVP nanofibers films catalyst was applied to catalytic hydrogenation of aryl nitro compounds reduction and Heck reactions to test the catalytic activity, products were characterized by gas chromatograph (GC) and gas chromatograph mass spectrometer (GC-MS). Results showed that the diameters of Pd NPs were 3-10 nm and the Pd NPs/PVP nanofibers films catalyst possessed high-activity, improved the selectivity and yield, the conversion rate of paratoluidine was 74.36%, N-butyl cinnamate esters conversion rate still exceed 99% after catalyst be used three times. It overcomes the problems that palladium has leached badly and recovery difficultly in conventional homogeneous palladium catalyst field, and have a broad foreground of catalyst applications.

  1. Electrospun PVP-indomethacin constituents for transdermal dressings and drug delivery devices.

    Science.gov (United States)

    Rasekh, Manoochehr; Karavasili, Christina; Soong, Yi Ling; Bouropoulos, Nikolaos; Morris, Mhairi; Armitage, David; Li, Xiang; Fatouros, Dimitrios G; Ahmad, Zeeshan

    2014-10-01

    A method in layering dressings with a superficial active layer of sub-micrometer scaled fibrous structures is demonstrated. For this, polyvinylpyrolidone (PVP)-indomethacin (INDO) fibres (5% w/v PVP, 5% w/w indomethacin, using a 50:50 ethanol-methanol solvent system) were produced at different flow rates (50 μL/min and 100 μL/min) via a modified electrospinning device head (applied voltage varied between 15 ± 2 kV). We further assessed these structures for their morphological, physical and chemical properties using SEM, AFM, DSC, XRD, FTIR and HPLC-UV. The average diameter of the resulting 3D (ca. 500 nm in height) PVP-INDO fibres produced at 50 μL/min flow rate was 2.58 ± 0.30 μm, while an almost two-fold increase in the diameter was observed (5.22 ± 0.83 μm) when the flow rate was doubled. However, both of these diameters were appreciably smaller than the existing dressing fibres (ca. 30 μm), which were visible even when layered with the active spun fibres. Indomethacin was incorporated in the amorphous state. The encapsulation efficiency was 75% w/w, with complete drug release in 45 min. The advantages are the ease of fabrication and deposition onto any existing normal or functionalised dressing (retaining the original fabric functionality), elimination of topical product issues (application, storage and transport), rapid release of active and controlled loading of drug content (fibre layer).

  2. Neurobiology of 3,4-methylenedioxypyrovalerone (MDPV) and α-pyrrolidinovalerophenone (α-PVP).

    Science.gov (United States)

    Glennon, Richard A; Young, Richard

    2016-09-01

    Synthetic cathinones are analogs of cathinone or β-ketoamphetamine - the major psychostimulant component of the shrub Catha edulis or khat. Cathinone analogs - though not termed as such - have been known for >100 years, but confusing chemical nomenclature often made the topic difficult to appreciate. In addition, many of the early analogs were prepared as synthetic precursors for the development of various other agents, and relatively few were pharmacologically evaluated. Cathinone is a close structural relative of amphetamine. Today, certain cathinone derivatives, synthetic cathinones, are known to produce central stimulant actions and represent a "new" class of drugs of abuse. Depending upon the nature of their terminal amine, α substituent, and aryl substituents, they seem to produce their effects via release or reuptake of various neurotansmitters including dopamine norepinephreine and/or serotonin. Two of the newest and most prominent members of the class are MDPV and its parent α-PVP ("flakka"). Both have been encountered on their own and in what might be constituents of what has been termed by a variety of names including psychoactive "bath salts". Here, we describe the nomenclature of synthetic cathinones, the mechanism(s) of action of MDPV and α-PVP, and their structure-activity relationships. In order to assist in forensic studies, and to identify novel substances requiring future pharmacological evaluation, the metabolism of these agents is also described. Finally, the preclinical behavioral actions of these two agents in a variety of behavioral assays, including rodent locomotor assays, self-administration studies, intracranial self-stimulation, conditioned place preference, and drug discrimination, is summarized. The results of these studies with MDPV and α-PVP are consistent with their acting as potent cocaine-like central stimulants with abuse liability. Copyright © 2016 Elsevier Inc. All rights reserved.

  3. Characterization and physical stability of spray dried solid dispersions of probucol and PVP-K30.

    Science.gov (United States)

    Thybo, Pia; Pedersen, Betty L; Hovgaard, Lars; Holm, Rene; Mullertz, Anette

    2008-01-01

    The main purpose of this study was to obtain stable, well-characterized solid dispersions (SDs) of amorphous probucol and polyvinylpyrrolidone K-30 (PVP-K30) with improved dissolution rates. A secondary aim was to investigate the flow-through dissolution method for in-vitro dissolution measurements of small-sized amorphous powders dispersed in a hydrophilic polymer. SDs were prepared by spray drying solutions of probucol and different amounts of PVP-K30. The obtained SDs were characterized by dissolution rate measurements in a flow-through apparatus, X-ray Powder Diffraction (XRPD), Differential Scanning Calorimetry (DSC), Scanning Electron Microscopy (SEM), particle sizing (laser diffraction) and Brunauer-Emmett-Teller Method (BET) and results were compared with starting material and a physical mixture. The physical stability was monitored after storage at 25 degrees C and 60% RH for up to 12 weeks. The flow-through method was found suitable as dissolution method. All SDs showed improved in-vitro dissolution rates when compared to starting material and physical mixtures. The greatest improvement in the in-vitro dissolution rate was observed for the highest polymer to drug ratio. By means of the results from XRPD and DSC, it was argued that the presence of amorphous probucol improved the dissolution rate, but the amorphous state could not fully account for the difference in dissolution profiles between the SDs. It was suggested that the increase in surface area due to the reduction in particle size contributed to an increased dissolution rate as well as the presence of PVP-K30 by preventing aggregation and drug re-crystallization and by improving wettability during dissolution. The stabilizing effect of the polymer was verified in the solid state, as all the SDs retained probucol in the amorphous state throughout the entire length of the stability study.

  4. Effect of antigravity suit inflation on cardiovascular, PRA, and PVP responses in humans.

    Science.gov (United States)

    Kravik, S E; Keil, L C; Geelen, G; Wade, C E; Barnes, P R; Spaul, W A; Elder, C A; Greenleaf, J E

    1986-08-01

    Blood pressure, pulse rate (PR), serum osmolality and electrolytes, as well as plasma vasopressin (PVP) and plasma renin activity (PRA), were measured in five men and two women [mean age 38.6 +/- 3.9 (SE) yr] before, during, and after inflation of an antigravity suit that covered the legs and abdomen. After 24 h of fluid deprivation the subjects stood quietly for 3 h: the 1st h without inflation, the 2nd with inflation to 60 Torr, and the 3rd without inflation. A similar control noninflation experiment was conducted 10 mo after the inflation experiment using five of the seven subjects except that the suit was not inflated during the 3-h period. Mean arterial pressure increased by 14 +/- 4 (SE) Torr (P less than 0.05) with inflation and decreased by 15 +/- 5 Torr (P less than 0.05) after deflation. Pulse pressure (PP) increased by 7 +/- 2 Torr (P less than 0.05) with inflation and PR decreased by 11 +/- 5 beats/min (P less than 0.05); PP and PR returned to preinflation levels after deflation. Plasma volume decreased by 6.1 +/- 1.5% and 5.3 +/- 1.6% (P less than 0.05) during hours 1 and 3, respectively, and returned to base line during inflation. Inflation decreased PVP from 6.8 +/- 1.1 to 5.6 +/- 1.4 pg/ml (P less than 0.05) and abolished the significant rise in PRA during hour 1. Both PVP and PRA increased significantly after deflation: delta = 18.0 +/- 5.1 pg/ml and 4.34 +/- 1.71 ng angiotensin I X ml-1 X h-1, respectively. Serum osmolality and Na+ and K+ concentrations were unchanged during the 3 h of standing.(ABSTRACT TRUNCATED AT 250 WORDS)

  5. Thermodynamic aspects of polymer–surfactant interactions: Gemini (16-5-16-PVP-water system

    Directory of Open Access Journals (Sweden)

    Naved Azum

    2016-11-01

    Full Text Available The interaction between polyvinylpyrrolidone (PVP and gemini surfactant (16-5-16 in aqueous solution has been analyzed using conductometry. From conductivity data the critical aggregation concentration (cac, critical micelle concentration (cmc, the effective degree of counter-ion binding (β at different temperatures were obtained. The thermodynamic parameters, i.e., Gibbs energy of aggregation and micellization, standard enthalpy of aggregation, and standard entropy of aggregation of surfactant/polymer system were estimated, employing pseudophase separation model. The negative values of Gibbs energy and standard enthalpy suggest that the surfactant/polymer aggregation process is spontaneous and exothermic respectively.

  6. High-energy radiation processing, a smart approach to obtain PVP-graft-AA nanogels

    Science.gov (United States)

    Grimaldi, N.; Sabatino, M. A.; Przybytniak, G.; Kaluska, I.; Bondì, M. L.; Bulone, D.; Alessi, S.; Spadaro, G.; Dispenza, C.

    2014-01-01

    Poly(N-vinylpyrrolidone)-grafted-acrylic acid biocompatible nanogels (NGs) were prepared using an exiting industrial-type electron accelerator and setups, starting from semi-dilute aqueous solutions of a commercial PVP and the acrylic acid monomer. As a result, NGs with tunable size and structure can be obtained quantitatively. Sterility was also imparted at the integrated dose absorbed. The chemical structure of the NGs produced was confirmed through Fourier Transformer Infrared Spectroscopy (FT-IR). The molecular and physico-chemical properties of NGs, such as the hydrodynamic dimensions and surface charge densities, for various polymer and monomer concentrations in the irradiated solutions, are discussed here.

  7. Formulation, Characterization, and in Vivo Evaluation of Celecoxib-PVP Solid Dispersion Nanoparticles Using Supercritical Antisolvent Process

    Directory of Open Access Journals (Sweden)

    Eun-Sol Ha

    2014-12-01

    Full Text Available The aim of this study was to develop celecoxib-polyvinylpyrrolidone (PVP solid dispersion nanoparticles with and without surfactant using the supercritical antisolvent (SAS process. The effect of different surfactants such as gelucire 44/14, poloxamer 188, poloxamer 407, Ryoto sugar ester L1695, and d-α-tocopheryl polyethylene glycol 1000 succinate (TPGS on nanoparticle formation and dissolution as well as oral absorption of celecoxib-PVP K30 solid dispersion nanoparticles was investigated. Spherical celecoxib solid dispersion nanoparticles less than 300 nm in size were successfully developed using the SAS process. Analysis by differential scanning calorimetry and powder X-ray diffraction showed that celecoxib existed in the amorphous form within the solid dispersion nanoparticles fabricated using the SAS process. The celecoxib-PVP-TPGS solid dispersion nanoparticles significantly enhanced in vitro dissolution and oral absorption of celecoxib relative to that of the unprocessed form. The area under the concentration-time curve (AUC0→24 h and peak plasma concentration (Cmax increased 4.6 and 5.7 times, respectively, with the celecoxib-PVP-TPGS formulation. In addition, in vitro dissolution efficiency was well correlated with in vivo pharmacokinetic parameters. The present study demonstrated that formulation of celecoxib-PVP-TPGS solid dispersion nanoparticles using the SAS process is a highly effective strategy for enhancing the bioavailability of poorly water-soluble celecoxib.

  8. Encapsulation of plai oil/2-hydroxypropyl-β-cyclodextrin inclusion complexes in polyvinylpyrrolidone (PVP) electrospun nanofibers for topical application.

    Science.gov (United States)

    Tonglairoum, Prasopchai; Chuchote, Tudduo; Ngawhirunpat, Tanasait; Rojanarata, Theerasak; Opanasopit, Praneet

    2014-06-01

    The aim of this study was to prepare electrospun polyvinylpyrrolidone (PVP)/2-hydroxypropyl-β-cyclodextrin (HPβCD) nanofiber mats and to incorporate plai oil (Zingiber Cassumunar Roxb.). The plai oil with 10, 20 and 30% wt to polymer were incorporated in the PVP/HPβCD solution and electrospun to obtain nanofibers. The morphology and structure of the PVP and PVP/HPβCD nanofiber mats with and without the plai oil were analyzed using scanning electron microscopy (SEM). The thermal behaviors of the nanofiber mats were characterized using differential scanning calorimeter (DSC). Terpinen-4-ol was used as a marker of the plai oil. The amount of plai oil remaining in the PVP/HPβCD nanofiber mats was determined using gas chromatography-mass spectoscopy (GC-MS). The SEM images revealed that all of the fibers were smooth. The average diameter of fibers was 212-450 nm, and decreased with the increasing of plai oil content. The release characteristics of plai oil from the fiber showed the fast release followed by a sustained release over the experimental time of 24 h. The release rate ranged was in the order of 10% > 20% ∼ 30% plai oil within 24 h. Electrospun fibers with 20% plai oil loading provided the controlled release and also showed the highest plai oil content. Hence, this electrospun nanofiber has a potential for use as an alternative topical application.

  9. Protein adsorption resistance of PVP-modified polyurethane film prepared by surface-initiated atom transfer radical polymerization

    Science.gov (United States)

    Yuan, Huihui; Qian, Bin; Zhang, Wei; Lan, Minbo

    2016-02-01

    An anti-fouling surface of polyurethane (PU) film grafted with Poly(N-vinylpyrrolidone) (PVP) was prepared through surface-initiated atom transfer radical polymerization (SI-ATRP). And the polymerization time was investigated to obtain PU films with PVP brushes of different lengths. The surface properties and protein adsorption of modified PU films were evaluated. The results showed that the hydrophilicity of PU-PVP films were improved with the increase of polymerization time, which was not positive correlation with the surface roughness due to the brush structure. Additionally, the protein resistance performance was promoted when prolonging the polymerization time. The best antifouling PU-PVP (6.0 h) film reduced the adsoption level of bovine serum albumin (BSA), lysozyme (LYS), and brovin serum fibrinogen (BFG) by 93.4%, 68.3%, 85.6%, respectively, compared to the unmodified PU film. The competitive adsorption of three proteins indicated that LYS preferentially adsorbed on the modified PU film, while BFG had the lowest adsorption selectivity. And the amount of BFG on PU-PVP (6.0 h) film reduced greatly to 0.08 μg/cm2, which was almost one-tenth of its adsorption from the single-protein system. Presented results suggested that both hydrophilicity and surface roughness might be the important factors in all cases of protein adsorption, and the competitive or selective adsorption might be related to the size of the proteins, especially on the non-charged films.

  10. Formulation, characterization, and in vivo evaluation of celecoxib-PVP solid dispersion nanoparticles using supercritical antisolvent process.

    Science.gov (United States)

    Ha, Eun-Sol; Choo, Gwang-Ho; Baek, In-Hwan; Kim, Min-Soo

    2014-12-04

    The aim of this study was to develop celecoxib-polyvinylpyrrolidone (PVP) solid dispersion nanoparticles with and without surfactant using the supercritical antisolvent (SAS) process. The effect of different surfactants such as gelucire 44/14, poloxamer 188, poloxamer 407, Ryoto sugar ester L1695, and d-α-tocopheryl polyethylene glycol 1000 succinate (TPGS) on nanoparticle formation and dissolution as well as oral absorption of celecoxib-PVP K30 solid dispersion nanoparticles was investigated. Spherical celecoxib solid dispersion nanoparticles less than 300 nm in size were successfully developed using the SAS process. Analysis by differential scanning calorimetry and powder X-ray diffraction showed that celecoxib existed in the amorphous form within the solid dispersion nanoparticles fabricated using the SAS process. The celecoxib-PVP-TPGS solid dispersion nanoparticles significantly enhanced in vitro dissolution and oral absorption of celecoxib relative to that of the unprocessed form. The area under the concentration-time curve (AUC0→24 h) and peak plasma concentration (Cmax) increased 4.6 and 5.7 times, respectively, with the celecoxib-PVP-TPGS formulation. In addition, in vitro dissolution efficiency was well correlated with in vivo pharmacokinetic parameters. The present study demonstrated that formulation of celecoxib-PVP-TPGS solid dispersion nanoparticles using the SAS process is a highly effective strategy for enhancing the bioavailability of poorly water-soluble celecoxib.

  11. Improved electrical properties of Fe nanofiller impregnated PEO + PVP:Li+ blended polymer electrolytes for lithium battery applications

    Science.gov (United States)

    Naveen Kumar, K.; Saijyothi, K.; Kang, Misook; Ratnakaram, Y. C.; Hari Krishna, K.; Jin, Dahee; Lee, Yong Min

    2016-07-01

    Solid polymer-blended electrolyte films of polyethylene oxide (PEO) + polyvinyl pyrrolidone (PVP)/lithium perchlorate embedded with iron (Fe) nanofiller in different concentrations have been synthesized by a solution casting method. The semicrystalline nature of these polymer electrolyte films has been confirmed from their XRD profiles. Polymer complex formation and ion-polymer interactions are systematically studied by FTIR and laser Raman spectral analysis. Surface morphological studies are carried out from SEM analysis. Dispersed Fe nanofiller size evaluation study has been carried out using transmission electron microscopy (TEM). In order to evaluate the thermal stability, decomposition temperature, and thermogravimetric dynamics, we carried out the TG/DTA measurement. Upon addition of Fe nanofiller to the PEO + PVP/Li+ electrolyte system, it was found to result in the enhancement of ionic conductivity. The maximum ionic conductivity has been set up to be 1.14 × 10-4 Scm-1 at the optimized concentration of 4 wt% Fe nanofiller-embedded PEO + PVP/Li+ polymer electrolyte nanocomposite at an ambient temperature. PEO + PVP/Li+ + Fe nanofiller (4 wt%) cell exhibited better performance in terms of cell parameters. Based on the cell parameters, the 4 wt% Fe nanofiller-dispersed PEO + PVP/Li+ polymer electrolyte system could be suggested as a perspective candidate for solid-state battery applications.

  12. Biological compatibility test on films of added SEO [poly(dimethyl siloxane)-co-poly(ethylene oxide)] PVP; Teste de biocompatibilidade de filmes de PVP com adicao de SEO [poli (dimetilsiloxano)-co-poli(oxido de etileno)

    Energy Technology Data Exchange (ETDEWEB)

    Rogero, Sizue O.; Souza-Bazzi, Aurea de; Higa, Olga Z. [Instituto de Pesquisas Energeticas e Nucleares (IPEN), Sao Paulo, SP (Brazil). Supervisao de Radiobiologia

    1999-11-01

    Membranes composed by polyvinylpyrrolidone (PVP), agar and water crosslinked by ionizing radiation, can have the mechanical properties improved by the addition of copolymers. Due to the hydrophilic property also by the medical grade as it is supplied, the copolymer poly(dimethyl siloxane)-co-poly(ethylene oxide) (SEO) was added to the PVP membranes. Varied concentrations of SEO were used in the preparation of PVP membranes by electron beam irradiation at dose rate of 25 kGy. For testing the bicompatibility of the SEO composed membrane the in vitro assay of cytotoxicity, with Chinese Hamster Ovary cells (CHO), was carried out. However, the membranes showed a cytotoxic characteristic in cell culture, which was stronger as the amount of SEO increased in the composition. (author) 5 refs., 1 fig., 1 tab.

  13. Effect of chitosan addition and gamma radiation on polymeric blends of PVP and PVAL; Efeito da adicao de quitosana e da radiacao gama em blendas polimericas de PVP e PVAL

    Energy Technology Data Exchange (ETDEWEB)

    Terence, M.C.; Castro, P.J.; Miranda, L.F.; Faldini, S.B., E-mail: mauroterence@yahoo.com.b [Universidade Presbiteriana Mackenzie, Sao Paulo. SP (Brazil). Dept. de Engenharia de Materiais

    2010-07-01

    The objective of this project is the study of the effect of chitosan addition and the radiation with gamma rays. The polymeric blend usage is a recent development that expanded the applications of the polymers, due to the improvement of the properties of a single polymer. The PVP and PVAL were chosen because they present the main required characteristics to the formation of a hydrogel, such as water absorption and crosslinking, and the chitosan to improve the interaction between the hydrogel and the organism. The flexibility of the PVP was added with the mechanical resistance of the PVAL and the chitosan biocompatibility. With a defined concentration of PVP and PVAL, films of this blend was irradiated and also solutions with different concentrations of chitosan was prepared to obtain new films of this blend. After obtaining the films, some assays were realized to evaluate the mechanical properties. (author)

  14. Functional fiber mats with tunable diffuse reflectance composed of electrospun VO2/PVP composite fibers.

    Science.gov (United States)

    Li, Shaotang; Li, Yamei; Qian, Kun; Ji, Shidong; Luo, Hongjie; Gao, Yanfeng; Jin, Ping

    2014-01-01

    Thermochromic VO2 nanoparticles have been dispersed into polyvinyl pyrrolidone (PVP) fibers by electrospinning of a VO2-PVP blend solution. The structure and optical properties of the obtained composite fiber mat were studied by X-ray diffraction (XRD), scanning electron microscopy (SEM), ultraviolet-visible (UV-Vis) spectrophotometry, and Fourier transform infrared (FT-IR) spectroscopy. The fiber mat revealed two diffuse reflectance states in infrared spectral region at temperatures under and above the phase transition temperature of VO2 and its IR reflectance is smaller in high temperature. The difference of diffuse reflectance between the two states (ΔRdif) was obvious to be more than 25% in the wavelengths from 1.5 μm to 6 μm. The diffuse reflectance of the fiber mat could be controlled by adjusting the diameter of the fiber or the content of VO2 in the fibers and this particular optical property was explained by a multiple scattering-absorbing process.

  15. Photocatalytic studies of crystal violet dye using mn doped and PVP capped ZnO nanoparticles.

    Science.gov (United States)

    Mittal, Manish; Sharma, Manoj; Pandey, O P

    2014-04-01

    Mn (0.5%, 1%, 1.5% and 2%) doped and undoped ZnO nanoparticles (NPs) capped with PVP (1.0%) were successfully synthesized via co-precipitation approach using zinc acetate, sodium hydroxide and manganese acetate as precursors. Structural analysis was performed by XRD confirming phase purity and crystalline wurtzite structure. TEM results show average particle size 15-20 nm and 22-25 nm for Mn (1%) and Mn (2%) doped ZnO NPs respectively. Manganese (Mn) doping has led to reduction in band gap which facilitate the absorption of radiation in visible region. The Photocatalytic activity of undoped and Mn (0.5%,1%,1.5% and 2%) doped NPs was analyzed via degradation of crystal violet (CV) dye. The crystal violet decomposition rate of undoped and Mn doped NPs were studied under UV-visible region. It is observed from degradation studies that the doping has a pronounced effect on the photocatalytic activity of ZnO NPs. Kinetic studies shows that photo degradation of CV follow a pseudo first-order kinetic law. Experiments for reusability of Mn (1%) doped with PVP (1%) capped ZnO were also performed to determine the stability of as prepared sample. It shows an increase in catalytic activity of NPs by small amount when exposed to UV irradiation for 3 h. Photoluminescence and UV-Visible absorption spectroscopy studies were also performed for studying the effect of UV irradiation on the surface of ZnO NPs.

  16. Optical, electrical, thermal properties of cadmium chloride doped PVA – PVP blend

    Energy Technology Data Exchange (ETDEWEB)

    Baraker, Basavarajeshwari M.; Hammannavar, Preeti B.; Lobo, Blaise, E-mail: blaise.lobo@gmail.com [Department of Physics, Karnatak Science College, Karnatak University, Dharwad-580001 (India)

    2015-06-24

    Films of polyvinylalcohol (PVA) – polyvinylpyrrolidone (PVP) blend doped with Cadmium Chloride (CdCl{sub 2}) in the doping range 1 wt% to 40 wt% were prepared by solution casting technique. These films were characterized using optical/UV-Vis- NIR spectroscopy, Differential Scanning Calorimetry (DSC) and DC electrical measurements. The UV-Visible spectra were quantitatively analyzed to yield the optical parameters. The UV-Visible Spectra show intermediate absorption bands (before the final absorption edge) due to formation of energy bands in the forbidden gap of PVA-PVP. There is a prominent absorption band at 2.9 eV, from 0.5 wt% up to 1.8 wt% doping level (DL) caused by the dopant (CdCl{sub 2}). The DC electrical studies showed an increase in activation energy from 2.8 eV at 0.5 wt% DL up to 3.5 eV at 4.4 wt% DL, reaching a low of 2.4 eV at 11.2 wt% DL. DSC scans show evidence of formation of chain fragments, at doping levels beyond 8 wt%.

  17. PVP/PEG/Carrageenan/Silver acetate hydrogels by {gamma}-ray

    Energy Technology Data Exchange (ETDEWEB)

    Lim, Youn Mook; Youn, Young; Gwon, Hui Jeong; Park, Jong Seok; Nho, Young Chang [Korea Atomic Energy Research Institute, Jeongeup (Korea, Republic of)

    2010-03-15

    In recent day, there is much interest in the biocidal activity of silver since silver is known to be safe and effective as disinifectant and biocidal material against coliforms and viruses. In this study, hydrogels containing silver acetate as antibacterial agent have been prepared using gamma rays irradiation. The hydrogels are composed of poly(vinyl pyrrolidone) (PVP), poly(ethylene glycol) (PEG), carrageenan and silver acetate. The concentration of solution was 9 wt%. The ratio of PVP: PEG: carrageenan was 6:1:2. The concentration of the silver acetate were 0,0.01, 0.03, 0.05 and 0.07% and Gamma irradiation dose was 25 kGy. The Gamma irradiation dose in hydrogels with 0.01% silver acetate were 20 kGy, 35 kGy, 50 kGy, 65 kGy, and 80 kGy. The results showed that 0.01% silver acetate concentration of hydrogels by 25 kGy irradiation dose showed the highest antibacterial activity against E. coli and Staphylococcus aureus. Moreover, antibacterial activity of various Gamma irradiation dose in hydrogels treated 0.01% silver acetate showed highest 35 kGy irradiation dose against Staphylococcus aureus.

  18. Preparation and Thermal Analysis of Ferric Doped PVA-PVP-PPy Composite Films

    Science.gov (United States)

    Patil, Ravikumar V.; Ranganath, M. R.; Lobo, Blaise

    2011-12-01

    The preparation and thermal analysis of flexible blend films of pyrrole (Py) polymerized in aqueous solution of poly (vinyl alcohol) (PVA) and poly (vinyl pyrrolidone) (PVP) is described. In-situ polymerization of pyrrole in aqueous solution of PVA and PVP containing ferric chloride (FeCl3) was achieved through vapor sorption, and the films obtained were studied using Differential Scanning Calorimetry (DSC), Thermo-Gravimetric Analysis (TGA) and Differential Thermal Analysis (DTA). No melting endotherm is seen in the DSC and DTA scans of the composite films, indicating that the sample is amorphous. Degradation of the sample is found to occur at lower temperatures, with increase in doping level (wt% of FeCl3). DSC study was performed between 40 °C and 400 °C. Below 1.2 wt % DL, degradation of the sample occurs in two stages, the first at 310 °C and the second at 440 °C, as seen from DTA and TGA scans. The broad endotherm between 80 °C and 120 °C is due to volatization of moisture (water) absorbed by the sample. Multiple endotherms are observed in DSC and DTA scans of the composite films, for FeCl3 doping levels above 3.8 wt %, and the sample degrades in many different stages at lower temperature, with increase in doping level, as revealed by weight losses in the TGA curve.

  19. Gamma-irradiation synthesis of iron oxide nanoparticles in the presence of PEO, PVP or CTAB

    Science.gov (United States)

    Jurkin, Tanja; Gotić, Marijan; Štefanić, Goran; Pucić, Irina

    2016-07-01

    Black hydrogels were synthesized using γ-irradiation of poly(ethylene oxide) (PEO)/iron(III) chloride precursor solutions. The magnetic properties of such hydrogels were improved by adding 2-propanol as a hydroxyl scavenger and/or NaBH4 as a strong chemical reducing agent; however, the rigidity and compactness of thus synthesized PEO hydrogels deteriorated. The magnetic suspension containing pure magnetite nanoparticles was obtained using γ-irradiation of an Fe(III)/PEO deoxygenated aqueous solution in the presence of 2-propanol and NaBH4. The γ-irradiation of an iron(III) chloride aqueous precursor solution in the presence of PVP produced a magnetic suspension due to the formation of a small amount of δ-FeOOH (feroxyhyte). The γ-irradiation of Fe(III)/CTAB (cetyltrimethylammonium bromide) aqueous solutions favored the formation of goethite. γ-irradiation in the presence of 2-propanol increased the yield of rod-like goethite nanoparticles. A small amount of δ-FeOOH found in the Fe(III)/PVP and Fe(III)/CTAB suspensions suggests the formation of Fe(OH)2upon γ-irradiation, which then under atmospheric conditions rapidly oxidized into δ-FeOOH.

  20. Effects of PVP K30 on Aqueous Solubility and Dissolution Properties of Daidzein%PVP K30 对葛根黄豆苷元溶解度和溶出的影响

    Institute of Scientific and Technical Information of China (English)

    郭圣荣; 郭丽

    2004-01-01

    Aim To study effects of PVP K30 on the aqueous solubility and dissolution properties of daidzein.Methods To measure the aqueous solubility and dissolution rates of daidzein in three different states (within solid dispersions, physical mixtures and as a pure drug) and investigate drug-polymer interactions in the solid state using X-ray powder diffraction and fourier-transform infrared spectroscopy.Results The negative values of the Gibbs free energy and enthalpy of transfer explained the spontaneous transfer of daidzein from phosphate buffer solution (PBS) to a solution of PVP in PBS.X-ray powder diffraction patterns showed that the drug was in the amorphous state (ratio of the drug ∶ PVP<1∶5) when dispersed in PVP K30.The infrared spectra indicated there exist interactions between the OH of daidzein and the C=O of PVP K30.Conclusion the dispersion of daidzein in PVP K30 considerably enhances the solubility and dissolution rate.%目的研究PVP K30 对葛根黄豆苷元水溶解性和溶出性质的影响.方法测量葛根黄豆苷元及其固体分散体、物理混合物的水溶解度和溶出速度,并用X-射线衍射、IR表征药物与PVP在固态条件下的相互作用.结果 Gibbs自由能和转移焓均小于零,表明葛根黄豆苷元从磷酸盐缓冲溶液中转移到PVP的磷酸盐缓冲溶液中是一自发的过程;X-射线衍射结果表明葛根黄豆苷元在PVP固体分散体(药物∶PVP < 1∶5)中以无定形形式存在; IR结果表明葛根黄豆苷元的羟基与PVP分子中的C=O之间存在相互作用.结论葛根黄豆苷元的PVP分散体可大大提高药物溶解度和溶出速度.

  1. Radiation preparation of drug carriers based polyacrylic acid (PAAc) using poly(vinyl pyrrolidone) (PVP) as a template polymer

    Energy Technology Data Exchange (ETDEWEB)

    Abd El-Rehim, H.A. [National Center for Radiation Research and Technology, Poymer, 3-Ahmed El-Zomor, P.O. Box 29, Cairo, Naser City (Egypt)]. E-mail: ha_rehim@hotmail.com; Hegazy, E.A. [National Center for Radiation Research and Technology, Poymer, 3-Ahmed El-Zomor, P.O. Box 29, Cairo, Naser City (Egypt); Khalil, F.H. [National Center for Radiation Research and Technology, Poymer, 3-Ahmed El-Zomor, P.O. Box 29, Cairo, Naser City (Egypt); Hamed, N.A. [National Center for Radiation Research and Technology, Poymer, 3-Ahmed El-Zomor, P.O. Box 29, Cairo, Naser City (Egypt)

    2007-01-15

    The present study deals with the radiation synthesis of stimuli response hydrophilic polymers from polyacrylic acid (PAAc). To maintain the property of PAAc and control the water swellibility for its application as a drug delivery system, radiation polymerization of AAc in the presence of poly(vinyl pyrrolidone) (PVP) as a template polymer was carried out. Characterization of the prepared PAA/PVP inter-polymer complex was investigated by determining gel content, swelling property, hydrogel microstructure and the release rate of caffeine as a model drug. The release rate of caffeine from the PAA/PVP inter-polymer complexes showed pH-dependency, and seemed to be mainly controlled by the dissolution rate of the complex above a pK {sub a} of PAAc. The prepared inter-polymer complex could be used for application as drug carriers.

  2. Protein adsorption resistance of PVP-modified polyurethane film prepared by surface-initiated atom transfer radical polymerization

    Energy Technology Data Exchange (ETDEWEB)

    Yuan, Huihui; Qian, Bin; Zhang, Wei [Shanghai Key Laboratory of Functional Materials Chemistry and Research Center of Analysis and Test, East China University of Science and Technology, Shanghai 200237 (China); Lan, Minbo, E-mail: minbolan@ecust.edu.cn [Shanghai Key Laboratory of Functional Materials Chemistry and Research Center of Analysis and Test, East China University of Science and Technology, Shanghai 200237 (China); State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237 (China)

    2016-02-15

    Highlights: • Antifouling PVP brushes were successfully grafted on PU films by SI-ATRP. • The effect of polymerization time on surface property and topography was studied. • Hydrophilicity and protein fouling resistance of PVP–PU films were greatly promoted. • Competitive adsorption of three proteins on PVP–PU films was evaluated. - Abstract: An anti-fouling surface of polyurethane (PU) film grafted with Poly(N-vinylpyrrolidone) (PVP) was prepared through surface-initiated atom transfer radical polymerization (SI-ATRP). And the polymerization time was investigated to obtain PU films with PVP brushes of different lengths. The surface properties and protein adsorption of modified PU films were evaluated. The results showed that the hydrophilicity of PU–PVP films were improved with the increase of polymerization time, which was not positive correlation with the surface roughness due to the brush structure. Additionally, the protein resistance performance was promoted when prolonging the polymerization time. The best antifouling PU–PVP (6.0 h) film reduced the adsoption level of bovine serum albumin (BSA), lysozyme (LYS), and brovin serum fibrinogen (BFG) by 93.4%, 68.3%, 85.6%, respectively, compared to the unmodified PU film. The competitive adsorption of three proteins indicated that LYS preferentially adsorbed on the modified PU film, while BFG had the lowest adsorption selectivity. And the amount of BFG on PU–PVP (6.0 h) film reduced greatly to 0.08 μg/cm{sup 2}, which was almost one-tenth of its adsorption from the single-protein system. Presented results suggested that both hydrophilicity and surface roughness might be the important factors in all cases of protein adsorption, and the competitive or selective adsorption might be related to the size of the proteins, especially on the non-charged films.

  3. Conformation-mediated Förster resonance energy transfer (FRET) in blue-emitting polyvinylpyrrolidone (PVP)-passivated zinc oxide (ZnO) nanoparticles.

    Science.gov (United States)

    Kurt, Hasan; Alpaslan, Ece; Yildiz, Burçin; Taralp, Alpay; Ow-Yang, Cleva W

    2017-02-15

    Homopolymers, such as polyvinylpyrrolidone (PVP), are commonly used to passivate the surface of blue-light emitting ZnO nanoparticles during colloid nucleation and growth. However, although PVP is known to auto-fluoresce at 400nm, which is near the absorption edge of ZnO, the impact of PVP adsorption characteristics on the surface of ZnO and the surface-related photophysics of PVP-capped ZnO nanoparticles is not well understood. To investigate, we have synthesized ZnO nanoparticles in solvents containing PVP of 3 concentrations-0.5, 0.7, and 0.11gmL(-1). Using time-domain NMR, we show that the adsorbed polymer conformation differs with polymer concentration-head-to-tail under low concentration (e.g., 0.05gmL(-1)) and looping, then train-like, with increasing concentration (e.g., 0.07gmL(-1) and 0.11gmL(-1), respectively). When the surface-adsorbed PVP is entrained, the surface states of ZnO are passivated and radiative emission from surface trap states is suppressed, allowing emission to be dominated by exciton transitions in the UV (ca. 310nm). Moreover, the reduced proximity between the PVP molecule and the ZnO gives rise to increased efficiency of energy transfer between the exciton emission of ZnO and the HOMO-LUMO absorption of PVP (ca. 400nm). As a result, light emission in the blue is enhanced in the PVP-capped ZnO nanoparticles. We thus show that the emission properties of ZnO can be tuned by controlling the adsorbed PVP conformation on the ZnO surface via the PVP concentration in the ZnO precipitation medium.

  4. Preparation and Characterization of HPMC/PVP Blend Films Plasticized with Sorbitol

    Directory of Open Access Journals (Sweden)

    H. Somashekarappa

    2013-01-01

    Full Text Available The aim of this present work is to investigate the effect of plasticizers like Sorbitol on microstructural and mechanical properties of hydroxypropyl methylcellulose (HPMC and Polyvinylpyrrolidone (PVP blend films. The pure blend and plasticized blend films were prepared by solution casting method and investigated using wide angle X-ray scattering (WAXS method. WAXS analysis confirms that the plasticizers can enter into macromolecular blend structure and destroy the crystallinity of the films. FTIR spectra show that there are a shift and decrease in the intensity of the peaks confirming the interaction of plasticizer with the blend. Mechanical properties like tensile strength and Young’s Modulus decrease up to 0.6% of Sorbitol content in the films. Percentage of elongation at break increases suggesting that the plasticized films are more flexible than pure blend films. These films are suitable to be used as environmental friendly and biodegradable packaging films.

  5. Influence of PVP on the Morphologies of Bi2S3 Nanostructures Synthesized by Solvothermal Method

    Directory of Open Access Journals (Sweden)

    Anukorn Phuruangrat

    2013-01-01

    Full Text Available Different morphologies of Bi2S3 nanostructures were synthesized by a 180°C and 12 h solvothermal reaction of solutions containing Bi(NO33·5H2O and thioacetamide (CH3CSNH2 in diethylene glycol (DEG as a solvent. The as-synthesized Bi2S3 products characterized by XRD, Raman spectroscopy, SEM, and TEM showed that they were well-crystallized orthorhombic Bi2S3 phase with morphologies of nanorod-like, sheaf-like, carnation-like, and microspherical, controlled by different contents of polyvinylpyrrolidone (PVP in the solutions. Based on the experimental results, a growth mechanism was also proposed and discussed.

  6. Radiation crosslinking polymerization of sterculia polysaccharide-PVA-PVP for making hydrogel wound dressings.

    Science.gov (United States)

    Singh, Baljit; Pal, Lok

    2011-04-01

    The present study deals with the modification of sterculia gum by PVA-PVP through radiation crosslinking, to develop the hydrogels meant for the delivery of antimicrobial agent to the wounds. The hydrogels were characterized by SEM, FTIR, TGA and swelling studies. For the evaluation of swelling and drug release mechanism, the swelling kinetics and in vitro release dynamics of model drug from this matrix have been studied respectively in the solution of different pHs and simulated wound fluid. After 24h swelling per gram of the hydrogel has taken (17.03±0.19)g of simulated wound fluid and has released (0.230±0.01)mg of drug in the simulated fluid. The release of drug in simulated fluids occurred through non-Fickian diffusion mechanism.

  7. High-Yield Synthesis of Uniform Ag Nanowires with High Aspect Ratios by Introducing the Long-Chain PVP in an Improved Polyol Process

    Directory of Open Access Journals (Sweden)

    Jie-Jun Zhu

    2011-01-01

    Full Text Available Polyvinyl pyrrolidone (PVP with different molecular weights was used as capping agent to synthesize silver nanowires through a polyol process. The results indicated that the yields and aspect ratios of silver nanowires were controlled by the chain length of PVP and increased with increasing the molecular weight (MW of PVP. When the long-chain PVP-K90 (MW = 800,000 was used, the product was uniform in size and was dominated by nanowires with high aspect ratios. The growth mechanism of the nanowires was studied. It is proposed that the chemical adsorption of Ag+ on the PVP chains at the initial stage promotes the growth of Ag nanowires.

  8. Investigating miscibility and molecular mobility of nifedipine-PVP amorphous solid dispersions using solid-state NMR spectroscopy.

    Science.gov (United States)

    Yuan, Xiaoda; Sperger, Diana; Munson, Eric J

    2014-01-06

    Solid-state NMR (SSNMR) (1)H T1 and T1ρ relaxation times were used to evaluate the miscibility of amorphous solid dispersions of nifedipine (NIF) and polyvinylpyrrolidone (PVP) prepared by three different methods: melt quenching in the typical lab setting, spray drying and melt quenching in the NMR rotor while spinning. Of the five compositions prepared by melt quenching in the lab setting, the 95:5 and 90:10 NIF:PVP (w:w) amorphous solid dispersions were not miscible while 75:25, 60:40, and 50:50 NIF:PVP dispersions were miscible by the (1)H T1ρ measurements. The domain size of the miscible systems was estimated to be less than 4.5 nm. Amorphous solid dispersions with composition of 90:10 NIF:PVP prepared by spray drying and melt quenching in the NMR rotor showed miscibility by (1)H T1ρ values. Variable-temperature SSNMR (1)H T1ρ relaxation measurements revealed a change in relaxation time at approximately 20 °C below Tg, suggesting increased molecular mobility above that temperature.

  9. Synthesis and characterization of PVP-functionalized superparamagnetic Fe3O4 nanoparticles as an MRI contrast agent

    Directory of Open Access Journals (Sweden)

    2010-06-01

    Full Text Available The magnetite (Fe3O4 nanoparticles (MNPs coated with poly(N-vinyl pyrrolidone (PVP via covalent bonds were prepared as T2 contrast agent for magnetic resonance imaging (MRI. The surface of MNPs was first coated with 3-(trimethoxysilyl propyl methacrylate (silan A by a silanization reaction to introduce reactive vinyl groups onto the surface, then poly(N-vinyl pyrrolidone was grafted onto the surface of modified-MNPs via surface-initiated radical polymerization. The obtained nanoparticles were characterized by FT-IR (Fourier transform infrared spectroscopy, XRD (X-ray diffraction, TEM (transmission electron microscopy, VSM (vibrating sample magnetometer, and TGA (thermogravimetric analysis. The MNPs had an average size of 14 nm and exhibited superparamagnetism and high saturation magnetization at room temperature. T2-weighted MRI images of PVP-grafted MNPs showed that the magnetic resonance signal is enhanced significantly with increasing nanoparticle concentration in water. The r1 and r2 values per millimole Fe, and r2/r1 value of the PVP-grafted MNPs were calculated to be 2.6 , 72.1, and 28.1(mmol/l–1•s–1, respectively. These results indicate that the PVP-grafted MNPs have great potential for application in MRI as a T2 contrast agent.

  10. Polyvinylpyrrolidone (PVP)-assisted solvothermal synthesis of flower-like SrCO{sub 3}:Tb{sup 3+} phosphors

    Energy Technology Data Exchange (ETDEWEB)

    Xue, Yannan; Ren, Xiaolei; Zhai, Xuefeng [Faculty of Chemistry, Northeast Normal University, Changchun 130024 (China); Yu, Min, E-mail: yum406@nenu.edu.cn [Faculty of Chemistry, Northeast Normal University, Changchun 130024 (China)

    2012-02-15

    Graphical abstract: A simple solvothermal method for the synthesis of flower-like SrCO{sub 3}:Tb{sup 3+} phosphors with the assistance of polyvinylpyrrolidone (PVP, K30). Highlights: Black-Right-Pointing-Pointer Well-crystallized flower-like SrCO{sub 3}:Tb{sup 3+} phosphors could be easily prepared by a simple solvothermal method with the assistance of polyvinylpyrrolidone (PVP). Black-Right-Pointing-Pointer The amount of PVP and the reaction time have a strong effect on controlling the morphology and optical properties of SrCO{sub 3}:Tb{sup 3+} particles. Black-Right-Pointing-Pointer The main synthesizing process and the growth mechanism for the formation of final samples were proposed. -- Abstract: Well-crystallized flower-like SrCO{sub 3}:Tb{sup 3+} phosphors have been synthesized by an inexpensive and friendly solvothermal process using polyvinylpyrrolidone (PVP, K30) as an additive without further annealing treatment. X-ray diffraction (XRD), Fourier transform-infrared spectroscopy (FT-IR), and field emission scanning electron microscopy (FESEM) as well as photoluminescence spectroscopy (PL) were used to characterize the resulting samples. The amount of PVP and the reaction time have strong effect on the morphology of the SrCO{sub 3}:Tb{sup 3+} particles. The results of XRD confirm the formation of a well-crystallized SrCO{sub 3} phase with an orthorhombic structure. The possible formation mechanism for flower-like SrCO{sub 3}:Tb{sup 3+} phosphor is proposed. The SrCO{sub 3}:Tb{sup 3+} phosphors show the characteristic {sup 5}D{sub 4}-{sup 7}F{sub J} (J = 6, 5, 4, 3) emission lines with green emission {sup 5}D{sub 4}-{sup 7}F{sub 5} (544 nm) as the most prominent group under ultraviolet excitation.

  11. Rapid microwave-assisted synthesis of PVP-coated ultrasmall gadolinium oxide nanoparticles for magnetic resonance imaging

    Energy Technology Data Exchange (ETDEWEB)

    Vahdatkhah, Parisa [Department of Materials Science and Engineering, Sharif University of Technology (Iran, Islamic Republic of); Madaah Hosseini, Hamid Reza, E-mail: Madaah@sharif.ir [Department of Materials Science and Engineering, Sharif University of Technology (Iran, Islamic Republic of); Khodaei, Azin [Department of Materials Science and Engineering, Sharif University of Technology (Iran, Islamic Republic of); Montazerabadi, Ali Reza [Department of Medical Physics and Biomedical Engineering, Tehran University of Medical Sciences (Iran, Islamic Republic of); Irajirad, Rasoul [Biomolecular Image Analysis Group, Research Center for Molecular and Cellular Imaging, Tehran University of Medical Sciences (Iran, Islamic Republic of); Oghabian, Mohamad Ali [Biomolecular Image Analysis Group, Research Center for Molecular and Cellular Imaging, Tehran University of Medical Sciences (Iran, Islamic Republic of); Department of Medical Physics and Biomedical Engineering, Tehran University of Medical Sciences (Iran, Islamic Republic of); Delavari, Hamid H., E-mail: Hamid.delavari@modares.ac.ir [Department of Materials Engineering, Tarbiat Modares University, Tehran, PO Box 14115-143 (Iran, Islamic Republic of)

    2015-05-12

    Highlights: • A rapid microwave-assisted polyol process used to synthesize Gd{sub 2}O{sub 3} nanoparticles. • In situ surface modification of ultrasmall Gd{sub 2}O{sub 3}NPs with PVP has been performed. • Gd{sub 2}O{sub 3}NPs shows considerable increasing of relaxivity in comparison to Gd-chelates. • PVP-covered Gd{sub 2}O{sub 3}NPs show appropriate stability for approximately 15 days. • Spectrophotometric indicates the leaching of free Gd ions not occurred versus time. - Abstract: Synthesis of polyvinyl pyrrolidone (PVP) coated ultrasmall Gd{sub 2}O{sub 3} nanoparticles (NPs) with enhanced T{sub 1}-weighted signal intensity and r{sub 2}/r{sub 1} ratio close to unity is performed by a microwave-assisted polyol process. PVP coated Gd{sub 2}O{sub 3}NPs with spherical shape and uniform size of 2.5 ± 0.5 nm have been synthesized below 5 min and structure and morphology confirmed by HRTEM, XRD and FTIR. The longitudinal (r{sub 1}) and transversal relaxation (r{sub 2}) of Gd{sub 2}O{sub 3}NPs is measured by a 3 T MRI scanner. The results showed considerable increasing of relaxivity for Gd{sub 2}O{sub 3}NPs in comparison to gadolinium chelates which are commonly used for clinical magnetic resonance imaging. In addition, a mechanism for Gd{sub 2}O{sub 3}NPs formation and in situ surface modification of PVP-grafted Gd{sub 2}O{sub 3}NPs is proposed.

  12. Characterization of modular bacteriophage endolysins from Myoviridae phages OBP, 201φ2-1 and PVP-SE1.

    Directory of Open Access Journals (Sweden)

    Maarten Walmagh

    Full Text Available Peptidoglycan lytic enzymes (endolysins induce bacterial host cell lysis in the late phase of the lytic bacteriophage replication cycle. Endolysins OBPgp279 (from Pseudomonas fluorescens phage OBP, PVP-SE1gp146 (Salmonella enterica serovar Enteritidis phage PVP-SE1 and 201φ2-1gp229 (Pseudomonas chlororaphis phage 201φ2-1 all possess a modular structure with an N-terminal cell wall binding domain and a C-terminal catalytic domain, a unique property for endolysins with a Gram-negative background. All three modular endolysins showed strong muralytic activity on the peptidoglycan of a broad range of Gram-negative bacteria, partly due to the presence of the cell wall binding domain. In the case of PVP-SE1gp146, this domain shows a binding affinity for Salmonella peptidoglycan that falls within the range of typical cell adhesion molecules (K(aff = 1.26 × 10(6 M(-1. Remarkably, PVP-SE1gp146 turns out to be thermoresistant up to temperatures of 90 °C, making it a potential candidate as antibacterial component in hurdle technology for food preservation. OBPgp279, on the other hand, is suggested to intrinsically destabilize the outer membrane of Pseudomonas species, thereby gaining access to their peptidoglycan and exerts an antibacterial activity of 1 logarithmic unit reduction. Addition of 0.5 mM EDTA significantly increases the antibacterial activity of the three modular endolysins up to 2-3 logarithmic units reduction. This research work offers perspectives towards elucidation of the structural differences explaining the unique biochemical and antibacterial properties of OBPgp279, PVP-SE1gp146 and 201φ2-1gp229. Furthermore, these endolysins extensively enlarge the pool of potential antibacterial compounds used against multi-drug resistant Gram-negative bacterial infections.

  13. PVP-coated silver nanoparticles block the transmission of cell-free and cell-associated HIV-1 in human cervical culture

    Directory of Open Access Journals (Sweden)

    Rodriguez-Padilla Cristina

    2010-07-01

    Full Text Available Abstract Background Previous in vitro studies have demonstrated that polyvinylpyrrolidone coated silver nanoparticles (PVP-coated AgNPs have antiviral activity against HIV-1 at non-cytotoxic concentrations. These particles also demonstrate broad spectrum virucidal activity by preventing the interaction of HIV-1 gp120 and cellular CD4, thereby inhibiting fusion or entry of the virus into the host cell. In this study, we evaluated the antiviral activity of PVP-coated AgNPs as a potential topical vaginal microbicide to prevent transmission of HIV-1 infection using human cervical culture, an in vitro model that simulates in vivo conditions. Results When formulated into a non-spermicidal gel (Replens at a concentration of 0.15 mg/mL, PVP-coated AgNPs prevented the transmission of cell-associated HIV-1 and cell-free HIV-1 isolates. Importantly, PVP-coated AgNPs were not toxic to the explant, even when the cervical tissues were exposed continuously to 0.15 mg/mL of PVP-coated AgNPs for 48 h. Only 1 min of PVP-coated AgNPs pretreatment to the explant was required to prevent transmission of HIV-1. Pre-treatment of the cervical explant with 0.15 mg/mL PVP-coated AgNPs for 20 min followed by extensive washing prevented the transmission of HIV-1 in this model for 48 h. Conclusions A formulation of PVP-coated AgNPs homogenized in Replens gel acts rapidly to inhibit HIV-1 transmission after 1 min and offers long-lasting protection of the cervical tissue from infection for 48 h, with no evidence of cytotoxicity observed in the explants. Based on this data, PVP-coated AgNPs are a promising microbicidal candidate for use in topical vaginal/cervical agents to prevent HIV-1 transmission, and further research is warranted.

  14. Sensitivity analyses of the theoretical equations used in point velocity probe (PVP) data interpretation

    Science.gov (United States)

    Devlin, J. F.

    2016-09-01

    Point velocity probes (PVPs) are dedicated, relatively low-cost instruments for measuring groundwater speed and direction in non-cohesive, unconsolidated porous media aquifers. They have been used to evaluate groundwater velocity in groundwater treatment zones, glacial outwash aquifers, and within streambanks to assist with the assessment of groundwater-surfaced water exchanges. Empirical evidence of acceptable levels of uncertainty for these applications has come from both laboratory and field trials. This work extends previous assessments of the method by examining the inherent uncertainties arising from the equations used to interpret PVP datasets. PVPs operate by sensing tracer movement on the probe surface, producing apparent velocities from two detectors. Sensitivity equations were developed for the estimation of groundwater speed, v∞, and flow direction, α, as a function of the apparent velocities of water on the probe surface and the α angle itself. The resulting estimations of measurement uncertainty, which are inherent limitations of the method, apply to idealized, homogeneous porous media, which on the local scale of a PVP measurement may be approached. This work does not address experimental sources of error that may arise from the presence of cohesive sediments that prevent collapse around the probe, the effects of centimeter-scale aquifer heterogeneities, or other complications related to borehole integrity or operator error, which could greatly exceed the inherent sources of error. However, the findings reported here have been shown to be in agreement with the previous empirical work. On this basis, properly installed and functioning PVPs should be expected to produce estimates of groundwater speed with uncertainties less than ± 15%, with the most accurate values of groundwater speed expected when horizontal flow is incident on the probe surface at about 50° from the active injection port. Directions can be measured with uncertainties less than

  15. Long-Term Physical Stability of PVP- and PVPVA-Amorphous Solid Dispersions.

    Science.gov (United States)

    Lehmkemper, Kristin; Kyeremateng, Samuel O; Heinzerling, Oliver; Degenhardt, Matthias; Sadowski, Gabriele

    2017-01-03

    The preparation of amorphous solid dispersion (ASD) formulations is a promising strategy to improve the bioavailability of an active pharmaceutical ingredient (API). By dissolving the API in a polymer it is stabilized in its amorphous form, which usually shows higher water solubility than its crystalline counterpart. To prevent recrystallization, the long-term physical stability of ASD formulations is of big interest. In this work, the solubility of the APIs acetaminophen and naproxen in the excipient polymers poly(vinylpyrrolidone) (PVP K25) and poly(vinylpyrrolidone-co-vinyl acetate) (PVPVA64) was calculated with three models: the Perturbed-Chain Statistical Associating Fluid Theory (PC-SAFT), the Flory-Huggins model (FH), and an empirical model (Kyeremateng et al., J. Pharm. Sci, 2014, 103, 2847-2858). PC-SAFT and FH were further used to predict the influence of relative humidity (RH) on the API solubility in the polymers. The Gordon-Taylor equation was applied to model the glass-transition temperature of dry ASD and at humid conditions. The calculations were validated by 18 months-long stability studies at standardized storage conditions, 25 °C/0% RH, 25 °C/60% RH, and 40 °C/75% RH. The results of the three modeling approaches for the API solubility in polymers agreed with the experimental solubility data, which are only accessible at high temperatures in dry polymers. However, at room temperature FH resulted in a lower solubility of the APIs in the dry polymers than PC-SAFT and the empirical model. The impact of RH on the solubility of acetaminophen was predicted to be small, but naproxen solubility in the polymers was predicted to decrease with increasing RH with both, PC-SAFT and FH. At 25 °C/60% RH and 40 °C/75% RH, PC-SAFT is in agreement with all results of the long-term stability studies, while FH underestimates the acetaminophen solubility in PVP K25 and PVPVA64.

  16. PVP capped silver nanocubes assisted removal of glyphosate from water-A photoluminescence study.

    Science.gov (United States)

    Sarkar, Sumit; Das, Ratan

    2017-10-05

    Glyphosate [N-phosphono-methylglycine (PMG)] is the most used herbicide worldwide and it has been reported very recently that Glyphosate is very harmful and can produce lots of diseases such as alzheimer and parkinson's disease, depression, cancer, infertility including genotoxic effects. As it is mostly present in stable water body and ground water system, its detection and removal is very important. Here, we have shown a fluorescence technique for the removal of glyphosate from water using chemically synthesized polyvinylpyrrolidone (PVP) silver nanocrystals. Transmission Electron Microscopy (TEM) study shows the average size of silver nanocrystals of 100nm approximately with a morphology of cubic shape. Glyphosate does not show absorption in the visible region. But both glyphosate and silver nanocrystals show strong fluorescence in the visible region. So, photoluminescence study has been successfully utilized to detect the glyphosate in water samples and on treating the glyphosate contaminated water sample with silver nanocrystals, the sample shows no emission peak of glyphosate at 458nm. Thus, this approach is a promising and very rapid method for the detection and removal of glyphosate from water samples on treatment with silver nanocubes. NMR spectra further confirms that the silver nanocrystals treated contaminated water samples are glyphosate free. Copyright © 2017 Elsevier B.V. All rights reserved.

  17. Radiological decontamination strippable coatings using PVA and PVP based core-shell polymeric scintillation materials

    Energy Technology Data Exchange (ETDEWEB)

    Hwang, Ho Sang; Seo, Bum Kyoung; Lee, Kune Woo [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2010-05-15

    Strippable coatings are innovative technologies for decontamination that effectively reduce loose contamination. These coatings are polymer mixtures, such as water-based organic polymers that are applied to a surface by paintbrush, roller or spray applicator. In this study, the core-shell composite polymer for decontamination from the surface contamination was synthesized by the method of emulsion polymerization and blends of polymers. The strippable polymer emulsion is composed of the poly(styrene-ethyl acrylate) [poly(St-EA)] composite polymer, poly(vinyl alcohol) (PVA) and polyvinylpyrrolidone (PVP). The morphology of the composite emulsion particle was core-shell structure, with polystyrene (PS) as the core and poly(ethyl acrylate) (PEA) as the shell. Core-shell polymers of styrene (St)/ethyl acrylate (EA) pair were prepared by sequential emulsion polymerization in the presence of sodium dodecyl sulfate (SDS) as an emulsifier using ammonium persulfate (APS) as an initiator. Related tests and analysis confirmed the success in synthesis of composite polymer. The products are characterized by FT-IR spectroscopy, TGA that were used, respectively, to show the structure, the thermal stability of the prepared polymer. Two-phase particles with a core-shell structure were obtained in experiments where the estimated glass transition temperature and the morphologies of emulsion particles. Decontamination factors (DF) of the strippable polymeric emulsion were evaluated with the polymer blend contents

  18. Change spectroscopic studies and optimization electrical properties of PVP/PEO doped copper phthalocyanines

    Energy Technology Data Exchange (ETDEWEB)

    Ragab, H.M., E-mail: yara20092009@yahoo.com [Department of Physics, Faculty of Science, Al-Azhar University, Girls Branch, Cairo 11754 (Egypt); Basic Science Department, Faculty of Preparatory Year, Hail University (Saudi Arabia); Ahmad, F.; Radwan, Sh.N. [Department of Physics, Faculty of Science, Al-Azhar University, Girls Branch, Cairo 11754 (Egypt)

    2016-12-01

    Composite films of polyvinyl pyrrolidone and Polyethylene oxide (PVP/PEO) blend doped with 1, 4 and 12 wt% of copper Phthalocyanines (CuPc) were prepared by casting method. The samples were studied using different techniques. The X-ray (XRD) revealed average crystallite size and X-ray intensity decrease at 1 CuPc %; this implies to an increase on the degree of amorphousity, then increase at CuPc >1%. The change in both the intensity and position of some absorption peaks of the blend with CuPc content were observed in Fourier transform infrared (FTIR) spectroscopy suggest the complexation of polymer blend. The UV–Vis spectroscopy revealed that the optical band gap decreases as well as band tail width increases with increasing CuPc concentration. It may be reflect the role of CuPc in modifying the electronic structure of the polymeric matrix. The charge carrier concentration is responsible for conductivity improvement in electrolytes rather than the mobility.

  19. Change spectroscopic studies and optimization electrical properties of PVP/PEO doped copper phthalocyanines

    Science.gov (United States)

    Ragab, H. M.; Ahmad, F.; Radwan, Sh. N.

    2016-12-01

    Composite films of polyvinyl pyrrolidone and Polyethylene oxide (PVP/PEO) blend doped with 1, 4 and 12 wt% of copper Phthalocyanines (CuPc) were prepared by casting method. The samples were studied using different techniques. The X-ray (XRD) revealed average crystallite size and X-ray intensity decrease at 1 CuPc %; this implies to an increase on the degree of amorphousity, then increase at CuPc >1%. The change in both the intensity and position of some absorption peaks of the blend with CuPc content were observed in Fourier transform infrared (FTIR) spectroscopy suggest the complexation of polymer blend. The UV-Vis spectroscopy revealed that the optical band gap decreases as well as band tail width increases with increasing CuPc concentration. It may be reflect the role of CuPc in modifying the electronic structure of the polymeric matrix. The charge carrier concentration is responsible for conductivity improvement in electrolytes rather than the mobility.

  20. Calcined Solution-Based PVP Influence on ZnO Semiconductor Nanoparticle Properties

    Directory of Open Access Journals (Sweden)

    Halimah Mohamed Kamari

    2017-02-01

    Full Text Available A water-based solution of polyvinylpyrrolidone (PVP at various concentrations and zinc nitrates were used in conjunction with calcination to produce zinc oxide semiconductor nanoparticles. The extent to which the zinc oxide semiconductor nanoparticles had become crystallized was measured using X-ray diffraction (XRD, whilst morphological characteristics were determined using scanning electron microscopy (SEM. Transmission electron microscopy (TEM supported by XRD results were used to evaluate the average particle size. Fourier transform infrared spectroscopy (FT-IR was then carried out in order to identify the composition phase, since this suggested that the samples contained metal oxide bands and that all organic compounds had been effectively removed after calcination. A UV-VIS spectrophotometer was used to determine the energy band gap and illustrate optical features. Additionally, photoluminescence (PL spectra revealed that the intensity of photoluminescence decreased with a decrease in particle size. The obtained results have mainly been inclusive for uses by several semiconductor applications in different fields, such as environmental applications and studies, since an absorption process for energy wavelengths could efficiently occur.

  1. Dehalogenation of Aryl Halides Catalyzed by MontK10 Immobilized PVP-Pd-Sn Catalyst in Aqueous System

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    A series of PVP-Pd-Sn/MontK10 catalysts were prepared by immobilization of PVP[poly(N-vinyl-2-pyrrolidone)] supported bimetallic catalyst using MontK10 as carrier. This catalyst has good catalytic activity for hydrogen transfer dehalogenation of aryl halides. The catalytic reaction was carried out in aqueous system in the presence of phase transfer catalyst and sodium formate as hydrogen source. The catalyst with loading Pd 0.19wt% and molar ratio of Pd/Sn 8:1 gives the highest activity and good stability. This catalyst is more reducible with NaBH4. It is also found that the catalyst is easily separated from the reaction system.

  2. MnO2/PVP/MWCNT hybrid nano composites as electrode materials for high performance supercapacitor

    Science.gov (United States)

    Jaggi, Neena; Sharma, Deepa; Sharma, Priya

    2016-10-01

    In this work, we developed supercapacitors with electrodes of manganese oxide (MnO2) and its nanocomposites with multiwalled carbon nanotubes (MWCNT) and polyvinylpyrrolidone (PVP) and studied the effect of the electrode material on various performance parameters of the supercapacitor. Cyclic voltammetry (CV) curves, galvanostatic charge/discharge measurement curves, XRD (x-ray diffraction), I-V characteristics and electrochemical impedance spectroscopy were employed for the characterization and analysis. CV curves were used to verify the supercapacitor behavior and the specific capacitance of the capacitors composed of the nanocomposite electrodes was calculated. I-V characteristics of MnO2 and MnO2/PVP/MWCNT were plotted and compared and conductivity measurements were also performed. Dielectric properties and equivalent series resistance were investigated using electrochemical impedance spectroscopy.

  3. Evaluation of the of antibacterial efficacy of polyvinylpyrrolidone (PVP) and tri-sodium citrate (TSC) silver nanoparticles

    Science.gov (United States)

    Dey, Arindam; Dasgupta, Abhirup; Kumar, Vijay; Tyagi, Aakriti; Verma, Anita Kamra

    2015-09-01

    We present silver nanoparticles as the new age broad spectrum antibiotic. Siver nanoparticles exhibit unique physical and chemical properties that make them suitable for understanding their biological potential as antimicrobials. In this study, we explored the antibacterial activity of silver nanoparticles (TSC-AgNPs) and silver nanoparticles doped with polyvinylpyrrolidone (PVP-AgNPs) against Gram-negative and Gram-positive bacteria, Escherichia coli (DH5α) and Staphylococcus aureus, (ATCC 13709). Nucleation and growth kinetics during the synthesis process of AgNPs were precisely controlled using citrate (TSC) and further doped with polyvinylpyrrolidone (PVP). This resulted in the formation of two different sized nanoparticles 34 and 54 nm with PDI of 0.426 and 0.643. The physical characterization was done by nanoparticle tracking analysis and scanning electron microscopy, the results of which are in unison with the digital light scattering data. We found the bactericidal effect for both TSC-AgNPs and PVP-AgNPs to be dose-dependent as determined by the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) against E. coli and S. aureus. Interestingly, we also observed that AgNPs showed enhanced antimicrobial activity with a MIC of 26.75 and 13.48 µg/ml for E. coli and S. aureus, respectively, while MBC for AgNPs are 53.23 and 26.75 µg/ml for E. coli and S. aureus, respectively. Moreover, AgNPs showed increased DNA degradation as observed confirming its higher efficacy as antibacterial agent than the PVP doped AgNPs.

  4. Characterization and optimization of electrospun TiO2/PVP nanofibers using Taguchi design of experiment method

    Directory of Open Access Journals (Sweden)

    H. Albetran

    2015-09-01

    Full Text Available TiO2 nanofibers were prepared within polyvinylpyrrolidone (PVP polymer using a combination of sol–gel and electrospinning techniques. Based on a Taguchi design of experiment (DoE method, the effects of sol–gel and electrospinning on the TiO2/PVP nanofibers’ diameter, including titanium isopropoxide (TiP concentration, flow rate, needle tip-to-collector distance, and applied voltage were evaluated. The analysis of DoE experiments for nanofiber diameters demonstrated that TiP concentration was the most significant factor. An optimum combination to obtain smallest diameters was also determined with a minimum variation for electrospun TiO2/PVP nanofibers. The optimum combination was determined to be a 60% TiP concentration, at a flow rate of 1 ml/h, with the needle tip-to-collector distance at 11 cm (position a, and the applied voltage of 18 kV. This combination was further validated by conducting a confirmation experiment that used two different needles to study the effect of needle size. The average nanofiber diameter was approximately the same for both needle sizes in good accordance with the optimum condition estimated by the Taguchi DoE method.

  5. PVP assisted solvothermal synthesis of uniform Cu{sub 2}FeSnS{sub 4} nanospheres

    Energy Technology Data Exchange (ETDEWEB)

    Cao, Meng; Li, Chao; Zhang, Binlei; Huang, Jian, E-mail: jianhuang@shu.edu.cn; Wang, Linjun; Shen, Yue, E-mail: yueshen@staff.shu.edu.cn

    2015-02-15

    Graphical abstract: TEM image of CFTS nanospheres synthesized with 0.2 g PVP and 40 ml EG at 180 °C for 24 h. - Highlights: • Cu{sub 2}FeSnS{sub 4} nanospheres were synthesized by solvothermal method. • PVP improved dispersibility and morphology of Cu{sub 2}FeSnS{sub 4} nanospheres greatly. • Optoelectronic properties of Cu{sub 2}FeSnS{sub 4} were enhanced after annealing process. - Abstract: Well dispersed Cu{sub 2}FeSnS{sub 4} (CFTS) nanospheres were firstly synthesized by a facile solvothermal method using ethylene glycol (EG) as the reaction medium and PVP as the surface ligand. The structural, morphological, chemical composition and optical properties of as-synthesized CFTS nanospheres were characterized using X-ray diffraction (XRD), Raman spectroscopy, energy dispersive X-ray spectrometry (EDS), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and UV-Vis spectrophotometry. The average particle sizes of the nanospheres were in the range of 0.4-0.6 μm. Time dependent SEM, XRD and EDS were measured to investigate the mechanism of the morphological evolution of CFTS nanospheres. The band-gap of the as-synthesized CFTS nanospheres was estimated to be about 1.33 eV from the UV-Vis absorption spectra. Photoresponses of CFTS nanospheres were confirmed by IV measurements under dark and light illumination. All these indicated their potential solar cell applications.

  6. Electrospun tri-layered zein/PVP-GO/zein nanofiber mats for providing biphasic drug release profiles.

    Science.gov (United States)

    Lee, Hoik; Xu, Gang; Kharaghani, Davood; Nishino, Masayoshi; Song, Kyung Hun; Lee, Jung Soon; Kim, Ick Soo

    2017-10-05

    Simple sequential electrospinning was utilized to create a functional tri-layered nanofiber mesh that achieves time-regulated biphasic drug release behavior. A tri-layered nanofiber mesh -composed of zein and poly(vinylpyrrolidone) (PVP) as the top/bottom and middle layers, respectively - was constructed through sequential electrospinning with ketoprofen (KET) as the model drug. PVP was blended with graphene oxide (GO) to improve the drug release functionality of PVP nanofiber as well as its mechanical properties. Scanning electron microscopy confirmed that the resultant nanofibers had a linear morphology, smooth surface, and tri-layered structure. In addition, X-ray diffraction patterns, differential scanning calorimetric analyses, and Fourier transform infrared spectra verified that the drugs were uniformly dispersed throughout the nanofiber due to good compatibility between the polymer and KET induced by hydrogen interaction. In vitro release test of the tri-layered structure, each component of which had distinct release features, successfully demonstrated time-regulated biphasic drug release. Also, it was confirmed that the drug release rate and duration can be controlled by designing a morphological feature - namely, mesh thickness - which was achieved by simply regulating the spinning time of the first and third layer. This multilayered electrospun nanofiber mesh fabricated by sequential electrospinning could provide a useful method of controlling drug release behavior over time, which will open new routes for practical applications and stimulate further research in the development of effective drug release carriers. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. Influence of PVP template on the formation of porous TiO2 nanofibers by electrospinning technique for dye-sensitized solar cell

    Science.gov (United States)

    Elayappan, Vijayakumar; Panneerselvam, Pratheep; Nemala, Sivasankar; Nallathambi, Karthick S.; Angaiah, Subramania

    2015-09-01

    The porous TiO2 nanofibers were prepared by electrospinning technique using polyvinylpyrrolidone (PVP) as template as well as pore-forming agent at the calcination temperature of 475 °C for 5 h. The influence of various concentrations of PVP (5, 8 and 10 wt%) on the surface area and porosity of the prepared TiO2 nanofibers (NFs) were studied by using BET-specific surface area analyzer. The TiO2 NFs obtained by using 5 wt% of PVP had higher surface area and porosity than those obtained by using 8 and 10 wt% of PVP. The prepared electrospun TiO2 NFs were characterized by using TG analysis, X-ray diffraction, FTIR, FE-SEM and TEM studies. Finally, dye-sensitized solar cells were assembled using the prepared TiO2 NFs as the photoanode, Pt as the cathode and 0.5 M 1-butyl-3-methylimidazolium iodide, 0.5 M LiI, 0.05 M I2, 0.5 M 4-tertbutylpyridine in acetonitrile as an electrolyte. Among the three photoanodes, the cell assembled using porous TiO2 NFs obtained by using 5 wt% of PVP showed higher power conversion efficiency (PCE) of 4.81 % than those obtained by using 8 and 10 wt% of PVP, which showed the lower PCE of 4.13 and 3.42 %, respectively.

  8. Influence of polymer molecular weight on in vitro dissolution behavior and in vivo performance of celecoxib:PVP amorphous solid dispersions.

    Science.gov (United States)

    Knopp, Matthias Manne; Nguyen, Julia Hoang; Becker, Christian; Francke, Nadine Monika; Jørgensen, Erling B; Holm, Per; Holm, René; Mu, Huiling; Rades, Thomas; Langguth, Peter

    2016-04-01

    In this study, the influence of the molecular weight of polyvinylpyrrolidone (PVP) on the non-sink in vitro dissolution and in vivo performance of celecoxib (CCX):PVP amorphous solid dispersions were investigated. The dissolution rate of CCX from the amorphous solid dispersions increased with decreasing PVP molecular weight and crystallization inhibition was increased with increasing molecular weight of PVP, but reached a maximum for PVP K30. This suggested that the crystallization inhibition was not proportional with molecular weight of the polymer, but rather there was an optimal molecular weight where the crystallization inhibition was strongest. Consistent with the findings from the non-sink in vitro dissolution tests, the amorphous solid dispersions with the highest molecular weight PVPs (K30 and K60) resulted in significantly higher in vivo bioavailability (AUC0-24h) compared with pure amorphous and crystalline CCX. A linear relationship between the in vitro and in vivo parameter AUC0-24h indicated that the simple non-sink in vitro dissolution method used in this study could be used to predict the in vivo performance of amorphous solid dispersion with good precision, which enabled a ranking between the different formulations. In conclusion, the findings of this study demonstrated that the in vitro and in vivo performance of CCX:PVP amorphous solid dispersions were significantly controlled by the molecular weight of the polymer.

  9. Synthesis and characterization of PVP-coated Co0.3 Zn0.7 Fe2 O4 ferrite nanoparticles

    Science.gov (United States)

    Jaberolansar, E.; Kameli, P.; Ahmadvand, H.; Salamati, H.

    2016-04-01

    Co0.3 Zn0.7 Fe2 O4 nanoparticles coated with polyvinylpirrolydone (PVP) were synthesized using the two-step chemical method. The structural and magnetic properties of uncoated and PVP -coated nanoparticles were studied by X-ray diffraction (XRD), Fourier transform infrared spectrometry (FTIR), transmission electron microscopy (TEM), ac susceptibility, and vibrating sample magnetometry (VSM). The XRD patterns revealed a single phase cubic spinel structure in both types of nanoparticles. Average crystallite size of the samples decreased from 35 to 16 nm after PVP coating. VSM results indicated no hysteresis in any of the samples, which suggested their supreparamagnetic behaviour at room temperature. Ac susceptibility measurements showed that strong inter-particle magnetic interactions led to a superspin glass-like behaviour at low temperatures. Moreover, inter-particle interactions were found to decrease with increasing PVP content as a result of surface coating of the magnetic nanoparticles. The same measurements showed that the relative sensitivity of the samples to applied frequency increased with increasing PVP content to reach its maximum for a PVP to Co0.3 Zn0.7 Fe2O4 nanoparticle ratio of 0.75.

  10. Developmental and reproductive toxicity of PVP/PEI-coated silver nanoparticles to zebrafish.

    Science.gov (United States)

    Orbea, Amaia; González-Soto, Nagore; Lacave, José María; Barrio, Irantzu; Cajaraville, Miren P

    2017-09-01

    Cellular and molecular mechanisms of toxicity of silver nanoparticles (NPs) and their toxicity to fish embryos after waterborne exposure have been widely investigated, but much less information is available regarding the effect of Ag NPs on physiological functions such as growth or reproduction. In this work, the effects of waterborne exposure of adult zebrafish (Danio rerio) to PVP/PEI coated Ag NPs (~5nm) on reproduction (fecundity) were investigated. Moreover, the development of the embryos after parental exposure was compared with the development of embryos after direct waterborne exposure to the NPs. For this, two experiments were run: 1) embryos from unexposed parents were treated for 5days with Ag NPs (10μgAgL(-1)-10mgAgL(-1)) and development was monitored, and 2) selected breeding zebrafish were exposed for 3weeks to 100ngAgL(-1) (environmentally relevant concentration) or to 10μgAgL(-1) of Ag NPs, fecundity was scored and development of resulting embryos was monitored up to 5days. Waterborne exposure of embryos to Ag NPs resulted in being highly toxic (LC50 at 120h=50μgAgL(-1)), causing 100% mortality during the first 24h of exposure at 0.1mgAgL(-1). Exposure of adults, even at the environmentally relevant silver concentration, caused a significant reduction of fecundity by the second week of treatment and resulting embryos showed a higher prevalence of malformations than control embryos. Exposed adult females presented higher prevalence of vacuolization in the liver. These results show that Ag NPs at an environmentally relevant concentration are able to affect population level parameters in zebrafish. Copyright © 2017 Elsevier Inc. All rights reserved.

  11. The Behavioral Profile of methylenedioxypyrovalerone (MDPV) and α-pyrrolidinopentiophenone (PVP) - A Systematic Review.

    Science.gov (United States)

    Stanciu, Cornel N; Penders, Thomas M; Gnanasegaram, Samantha A; Pirapakaran, Elvin; Padda, Juvraj S; Padda, Jeeven S

    2017-03-21

    New psychoactive substances are emerging at an alarming rate. With novel structures and properties they produce unique behavioral characteristics during intoxication. Synthetic cathinones are some of the most common. More and more are presenting to emergency departments due to consequences of use. Aside from isolated reports, little is known about these compounds. Here we review literature pertaining to two common synthetic cathinones, MDPV and alphaPVP, and correlate clinically with guidance on management of intoxications. We searched the literature using predefined search terms for publications between January1985 and November2016. English language literature pertaining to humans only was considered. Returns were supplemented by citations of search returns, and credible online sources Results:Synthetic cathinones exert their action by blocking re-uptake of norepinephrine and dopamine, concentrating these in the synaptic cleft. Due to short duration of action, users re-dose frequently and compulsively leading to, and persisting into, delirium. Aside from disorganization, delusional thinking and hallucinations, some patients experience a more severe consequence- excited delirium. This is characterized by intense paranoia followed by very violent behavior often requiring physical interventions. Restraints are associated with increased mortality. Early recognition of the toxidrome allows for stress reduction and implementation of supportive care and sedation while avoiding dopaminergic agents. The trend of new molecules entering the market will continue and with it we will encounter more and more cases in our clinical practice. Standard drug testing is unlikely to confer much guidance. Clinicians must be aware of such presentations and be able to manage them accordingly, minimizing unwanted harm. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  12. Ag/PVP/PVA抗菌水凝胶的制备及性能%The Preparation and Properties of Ag/PVP/PVA Hydrogels with Anti-Bacterial Activity

    Institute of Scientific and Technical Information of China (English)

    范士军; 唐群委; 吴季怀; 胡德; 林建明

    2009-01-01

    Nanometer silver colloid were synthesized from AgNO_3 by chemical reduction in the liquid phase with hydrazine hydrate as the reducing agent, polyvinyl pyrrolidone(PVP) as the protective agents, and physically cross-linked nanometer silver/polyvinylpyrrolidone/polyvinyl alcohol (Ag/PVP/PVA) hydrogels were synthesized by freezing at - 20℃ and thawing at 20 ℃. The product was characterized by transmission electron microscopy (TEM), UV-vis spectrophotometer(UV-vis), X-ray diffraction(XRD) and fourier transform infrared spectroscopy (FT-IR), the antimicrobial mechanism and property were investigated by escherichia coli as a model in this work. And the results show that nanosilver particles are about 50 nm in size, the hydrogels held antibacterial properties for the presence of silver nanocomposites, is a prospective biology material.%采用液相还原法,以聚乙烯吡咯烷酮(PVP)为保护剂,水合肼直接还原硝酸银溶液得到稳定分散的纳米银溶胶,并通过冷冻(-20℃)、解冻(20℃)法合成了物理交联的Ag/PVP/PVA水凝胶.利用透射电子显微镜(TEM)、紫外可见光谱(UV-vis)、X射线衍射(XRD)以及红外分析(FT-IR)对制备的复合材料进行了表征,以大肠杆茵为细茵模型测试了样品的抗茵性能并分析了抗茵原理.结果表明,所得银溶胶中纳米银平均粒径约为50nm,由于纳米银的引入,该新型水凝胶具有抗茵性能,是一种具有开发前景的复合材料.

  13. The optical band gap investigation of PVP-capped ZnO nanoparticles synthesized by sol-gel method

    Science.gov (United States)

    Yuliah, Yayah; Bahtiar, Ayi; Fitrilawati, Siregar, Rustam E.

    2016-02-01

    ZnO Nanoparticles (NPs) has unique natures on their crystal structure, direct band gap and high exciton binding energy, consequently applied in optoelectronic devices such as solar cells, optical wave guide and light emitting diodes (LED). However the drawback was ZnO NPs tend to agglomerate and turn to nano-structured materials with poor properties. Effort to avoid agglomerations generally resolved by surface modification of ZnO NPs to obtain well-dispersed suspension. However changes in the surface of ZnO NPs may change the electronic structure and density of states of ZnO NPs, in turn may change the optical band gap. Thus, the objective of current research is investigation of optical band gap of ZnO NPs due to surface modification by capping agent of poly-4-vinylpyrrolidone (PVP) molecules. Uncapped and PVP-capped ZnO nanoparticles were prepared by sol-gel method. The characteristics of surface modifications were investigated by UV-Vis and Photo Luminescence spectroscopy and Transmission Electron Microscope (TEM). The results shows the surface modification has change the band gap of ZnO NPs obtained at second precipitated stage. In contrast, the change of the optical band gap did not observe due to the surface modification of ZnO NPs obtained at the first stage. It was concluded that PVP capping on ZnO NPs did not affect on the band gap when the capping was performed on first stage. It is emphasized that this statement also supported by TEM images observations.

  14. PVP/(AA-co-AMPS)互穿网络水凝胶的制备及其电场响应性研究%Study on Preparation and Electronic Responsivity of PVP/(AA-co-AMPS) Novel IPN Hydrogels

    Institute of Scientific and Technical Information of China (English)

    马驰; 陈尔凡; T Vladlkova; 刘艺

    2007-01-01

    通过两步溶液聚合的方法制备了由丙烯酸单体(AA)与2-丙烯酰胺-2-甲基丙磺酸(AMPS)的共聚物和聚乙烯基吡咯烷酮(PVP)形成的具有互穿网络状结构(IPN)的新型聚合物水凝胶.并研究了共聚单体配比、PVP和交联剂对水凝胶电场响应性及力学性能的影响.探索了凝胶在电场作用下的弯曲机理.实验结果表明:此种具有IPN结构的凝胶具有较好的电场响应性和力学强度.当n(AA):n(AMPS)达到7:3,w(PVP)=16%,w(交联剂)=0.05%时,水凝胶的综合性能达到最好.

  15. Investigation on Effect of PVP on Morphological Changes and Crystallization Behavior of Nylon 6 in PVP/Nylon 6 Blends by FTIR Spectroscopy%PVP对Nylon 6形貌及结晶行为影响的研究

    Institute of Scientific and Technical Information of China (English)

    郝超伟; 赵莹; 李万利; 徐怡庄; 王笃金; 徐端夫

    2008-01-01

    采用变温红外光谱、示差扫描量热(DSC)和偏光显微镜(POM)等方法研究了聚乙烯吡咯烷酮(PVP)与尼龙6(nylon 6)分子间的相互作用及其对nylon 6热行为及结晶形貌的影响.DSC结果表明PVP的加入明显影响了nylon 6的熔融和结晶行为:随着PVP含量增加,PVP/nylon 6共混物的结晶温度、熔融温度及结晶度均逐渐降低;POM观察显示:随着PVP含量增多,nylon 6的球晶尺寸变小、球晶逐渐变得不完善.变温红外光谱结果表明,无定形PVP分子的羰基能够与nylon 6分子的N-H基团形成新的氢键,部分破坏了nylon 6分子之间的氢键结构,从而阻碍了nylon 6分子的规整排列,使其结晶度降低并导致nylon6结晶形貌的变化.

  16. Using DVS-NIR to assess the water sorption behaviour and stability of a griseofulvin/PVP K30 solid dispersion.

    Science.gov (United States)

    Li, Wanjing; Buckton, Graham

    2015-11-30

    The purpose of this work was to investigate the distribution of water in a physically unstable amorphous solid dispersion (polyvinylpyrrolidone (PVP) and griseofulvin (as a model hydrophobic drug)), both as the sample absorbs water and during prolonged exposure to elevated humidity by use of dynamic vapour sorption combined with near infrared (DVS-NIR). The solid dispersion absorbed much less water than the sum of the water sorption of the individual components. This suggests that griseofulvin hindered PVP from absorbing water through the formation of the solid dispersion. Prolonged storage of the solid dispersion at 75% RH resulted in no significant mass change. Whilst this would usually be interpreted as the absence of crystallization, the NIR spectra demonstrated that crystallization occurred. The reason for the lack of a weight loss was that the expelled water from amorphous griseofulvin was sorbed by PVP, meaning that as the dispersion was broken by the crystallisation of griseofulvin, the PVP was once again free to sorb water (in line with the higher water sorption shown by PVP alone, and in contrast with the lower sorption of water by the solid dispersion). As water is a key factor in the physical stability of amorphous systems, understanding how and where water is absorbed and how this is liable to change is an important advance and offers promise in understanding the mechanism of stabilisation of solid dispersions, and therefore may be useful to predict the stability of new API dispersions.

  17. Energy transfer based photoluminescence properties of co-doped (Er3+ + Pr3+): PEO + PVP blended polymer composites for photonic applications

    Science.gov (United States)

    Naveen Kumar, K.; Kang, Misook; Bhaskar Kumar, G.; Ratnakaram, Y. C.

    2016-04-01

    Er3+, Pr3+ singly doped and co-doped PEO + PVP polymer composites have been synthesized by conventional solution casting method. The structural analysis has been carried out for all these polymer composites from XRD analysis. Raman spectral studies confirm the ion-polymer interactions and polymer complex formation. Thermal properties of pure polymer film has also been clearly elucidated by TG/DTA profiles. Well defined optical absorption bands pertaining to Er3+ and Pr3+ are observed in the absorption spectral profile and these bands are assigned with corresponding electronic transitions. The polymer films containing singly doped Er3+ and Pr3+ ions have displayed green and red emissions at 510 nm (2H11/2 → 4I15/2) and 688 nm (3P0 → 3F3) respectively under UV excitation source. Comparing the emission spectra of singly Er3+ and co-doped Er3+ + Pr3+: PEO + PVP polymer films, a significant red emission pertaining to Pr3+ions is remarkably enhanced in co-doped polymer system. This could be ascribed to possible energy transfer from Er3+ to Pr3+ in co-doped polymer system. The energy transfer mechanism is clearly demonstrated using their emission performances, overlapped spectral profiles and also life time decay dynamics. Thus, it could be suggested that Er3+: PEO + PVP, Pr3+: PEO + PVP and (Er3+ + Pr3+): PEO + PVP blended polymer films are potential materials for several photonic applications.

  18. Response surface method (RSM) for optimization of ionic conductivity of membranes polymer electrolyte poly (vinylidene fluoride) (PVDF) with polyvinyl pyrrolidone (PVP) as pore forming agent

    Science.gov (United States)

    Dyartanti, E. R.; Susanto, H.; Widiasa, I. N.; Purwanto, A.

    2017-06-01

    The Membranes Polymer Gel Electrolyte (MPGEs) based poly (vinylidene fluoride) (PVDF) was prepared by a phase inversion method using polyvinyl pyrrolidone (PVP) as a pore-forming agent and N, N-dimethyl acetamide (DMAc) as a solvent and water as non solvet. The membranes were then soaked in 1 M lithium hexafluorophosphate (LiPF6) in ethylene carbonate (EC) / dimethyl carbonate (DMC) / Diethyl carbonate (DEC) (4:2:4 %vol) solution in order to prepare polymer electrolyte membranes. The MPEGs PVDF/PVP/Nanoclay was applied using central composite design (CCD) experimental design to obtain a quantitative relationship between selected membranes prepared parameters namely (PVDF, PVP as pore forming agent and nanoclay filler concentration) and Ionic conductivity MPEGs. The model was used to find the optimum ionic conductivity from polymer electrolyte membranes. The polymer electrolyte membranes show good ionic conductivity on the order of 6.3 - 8.7 x 10-3 S cm-1 at the ambient temperatures. The ionic conductivity tended to increase with PVP and nanoclay concentration and decrease with PVDF composition. The model predicted the maximum ionic conductivity of 8.47 x 10-3 S cm-1 when the PVDF, PVP and nanoclay concentration were set at 8.01 %, 8.04 % and 10.12%, respectively. The first section in your paper.

  19. Study on characteristics of PVDF/nano-clay composite polymer electrolyte using PVP as pore-forming agent

    Energy Technology Data Exchange (ETDEWEB)

    Dyartanti, Endah R., E-mail: heru.susanto@undip.ac.id, E-mail: endah-rd@uns.ac.id [Departement of Chemical Engineering, Sebelas Maret University, Surakarta (Indonesia); Department of Chemical Engineering, Diponegoro University, Semarang (Indonesia); Purwanto, Agus [Departement of Chemical Engineering, Sebelas Maret University, Surakarta (Indonesia); Widiasa, I. Nyoman; Susanto, Heru, E-mail: heru.susanto@undip.ac.id, E-mail: endah-rd@uns.ac.id [Department of Chemical Engineering, Diponegoro University, Semarang (Indonesia)

    2016-02-08

    Polyvinylidene fluoride (PVDF) based polymer electrolytes have a high dielectric constant, which can assist in greater ionization of lithium salts. The main advantages of PVDF are its durability in long battery operation and its ability to be a good ion conductor. However, the limitation of this polymer is its crystalline molecular structure. Dispersing nano-particles in the polymer matrix may improve the characteristics of the PVDF polymer. This paper aims to investigate the impact of nano-clay addition on the characteristics of PVDF polymer to be used as a polymer electrolyte membrane. In addition, the effect of poly(vinyl pyrrolidone) (PVP) is also investigated. The membrane was prepared by phase separation method whereas the polymer electrolyte membranes was prepared by immersing into 1 M lithium hexafluorophosphate (LiPF{sub 6}) in ethylene carbonate/dimethyl carbonate (EC/DMC) electrolytes for 1 h. The membranes were characterized by scanning electron microscope (SEM), porosity and electrolyte uptake and performance in battery cell. The results showed that both nano-clay and PVP have significant impacts on the improvement of PVDF membranes to be used as polymer electrolyte.

  20. Increased photocatalytic activity of tube-brush-like ZnO nanostructures fabricated by using PVP nanofibers as templates

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Xinying; Zhai, Yingjiao [School of Science, International Joint Research Center for Nanophotonics and Biophotonics, Changchun University of Science and Technology, 7089 Wei-Xing Road, Changchun 130022 (China); Li, Jinhua, E-mail: jhli_cust@163.com [School of Science, International Joint Research Center for Nanophotonics and Biophotonics, Changchun University of Science and Technology, 7089 Wei-Xing Road, Changchun 130022 (China); Fang, Xuan [School of Science, International Joint Research Center for Nanophotonics and Biophotonics, Changchun University of Science and Technology, 7089 Wei-Xing Road, Changchun 130022 (China); State Key Laboratory of High Power Semiconductor Laser, Changchun University of Science and Technology, 7089 Wei-Xing Road, Changchun 130022 (China); Fang, Fang; Chu, Xueying [School of Science, International Joint Research Center for Nanophotonics and Biophotonics, Changchun University of Science and Technology, 7089 Wei-Xing Road, Changchun 130022 (China); Wei, Zhipeng; Wang, Xiaohua [State Key Laboratory of High Power Semiconductor Laser, Changchun University of Science and Technology, 7089 Wei-Xing Road, Changchun 130022 (China)

    2014-11-15

    Highlights: • We obtained the tube-brush-like ZnO nanostructures. • We used polyvinylpyrrolidone (PVP) nanofibers used as templates by ALD and hydrothermal method to prepare tube-brush-like ZnO nanostructure. • The tube-brush-like ZnO nanostructures showed higher photocatalytic activity, the degradation of Rhodamine B (RhB) was up to 98% after 2 h of irradiation. - Abstract: The tube-brush-like ZnO nanostructures were synthesized by hydrothermal method using electrospinning polyvinylpyrrolidone (PVP) nanofibers as templates. The photocatalytic activity of as-grown samples was investigated by photo-degradation of Rhodamine B (RhB). The products were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), UV/visible absorption spectroscopy (UV–vis) and photoluminescence (PL) spectroscopy. It was found that the morphologies of the prepared ZnO were tube-brush-like nanostructures. With the grown time increasing, the crystal and the optical properties were improved. In the photocatalytic experiment, the tube-brush-like ZnO nanostructures photocatalytic activity was enhanced the degradation of RhB was up to 98% after 2 h of irradiation. The tube-brush-like ZnO nanostructures showed higher photocatalytic activity because of the special surface morphology.

  1. Synthesis and analysis of Fe3+, Co2+ and Ni2+ : PEO + PVP blended polymer composite films for multifunctional polymer applications

    Indian Academy of Sciences (India)

    K Naveen Kumar; M Vasudeva Reddy; L Vijayalakshmi; Y C Ratnakaram

    2015-08-01

    Blended polymer films of polyethylene oxide + polyvinyl pyrrolidone (PEO + PVP) containing transition metal (TM) ions like Fe3+, Co2+ and Ni2+ have been synthesized by a solution casting method. For these films, structural, thermal, magnetic and optical properties have been studied. X-ray diffraction results reveal the semi-crystalline nature of the polymer films. Thermal stability of the host (undoped) polymer film has been investigated from its thermogravimetric–differential thermal analysis profiles. Raman spectral profiles indicate a complex formation trend owing to the addition of TM ions into the host matrix. Co2+, Fe3+ and Ni2+ ions doped polymer films have revealed ferromagnetism based on their vibrating sample magnetometre profiles. However, the host polymer film has exhibited a paramagnetic nature. Further, ionic conductivities have been calculated using an impedance analyser at different temperatures for all the samples. Among these films, a maximum ionic conductivity ( = 7.5 × 10−6 S cm−1) has been noticed from PEO + PVP : Ni2+ polymer film at 373 K. Emission analysis of Co2+ : PEO + PVP polymer film has exhibited a strong red emission under an UV source and from both PEO + PVP : Fe3+; PEO + PVP: Ni2+, green emissions have commonly been noticed under an UV source. Thus, based on these results, it could be suggested that these TM ions doped PEO + PVP polymer films are found to be potential multifunctional materials for magneto-electric, magneto-optic fields with encouraging electrical, dielectric and optical properties as well as displaying with ferromagnetic nature from the doped films.

  2. In situ FTIR spectroscopic study of the effect of CO 2 sorption on H-bonding in PEG-PVP mixtures

    Science.gov (United States)

    Labuschagne, Philip W.; Kazarian, Sergei G.; Sadiku, Rotimi E.

    2011-05-01

    A study of the H-bonding between poly(ethylene glycol) (PEG) and polyvinylpyrrolidone (PVP) in the presence of supercritical carbon dioxide at various temperatures, pressures, different Mw of PEG and PVP and different PEG/PVP ratios is presented. In situ attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy was used to investigate H-bonding by examining changes in the relative intensities and positions of peak maxima of the 2nd derivative ν(C dbnd O) bands associated with 'free' and H-bonded C dbnd O groups. In general, relative intensities of bands associated with H-bonded C dbnd O groups decreased upon CO 2 sorption and was accompanied by an increase in intensity of bands associated with 'free' C dbnd O groups. At the same time, these bands were shifted to higher wavenumbers. These shifts were attributed to the shielding effect of CO 2 molecules on H-bonding interactions between PEG and PVP. The magnitude of the effects of CO 2 shielding generally increased with decreasing polymer Mw and increasing CO 2 content. However, upon CO 2 venting the extent of the H-bonding between PEG and PVP reappeared. The extent of H-bonding recovery was greatest for blends with low Mw PEG ( Mw: 4 × 10 2) and PVP ( Mw: 9 × 10 3) and PEG content ≥0.54 wt% under mild conditions of pressure (80 bar) and temperature (35 °C). For the same low Mw blends, increasing pressure to 150 bar, or temperature to 50 °C, showed poor H-bond recovery upon CO 2 venting. Overall, it was shown that supercritical CO 2-induced shielding of H-bonding interactions in polymer blends is reversible upon CO 2 venting, and the magnitude of both was influenced by processing conditions and blend composition.

  3. In situ FTIR spectroscopic study of the effect of CO2 sorption on H-bonding in PEG-PVP mixtures.

    Science.gov (United States)

    Labuschagne, Philip W; Kazarian, Sergei G; Sadiku, Rotimi E

    2011-05-01

    A study of the H-bonding between poly(ethylene glycol) (PEG) and polyvinylpyrrolidone (PVP) in the presence of supercritical carbon dioxide at various temperatures, pressures, different M(w) of PEG and PVP and different PEG/PVP ratios is presented. In situ attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy was used to investigate H-bonding by examining changes in the relative intensities and positions of peak maxima of the 2nd derivative ν(C=O) bands associated with 'free' and H-bonded C=O groups. In general, relative intensities of bands associated with H-bonded CO groups decreased upon CO(2) sorption and was accompanied by an increase in intensity of bands associated with 'free' C=O groups. At the same time, these bands were shifted to higher wavenumbers. These shifts were attributed to the shielding effect of CO(2) molecules on H-bonding interactions between PEG and PVP. The magnitude of the effects of CO(2) shielding generally increased with decreasing polymer M(w) and increasing CO(2) content. However, upon CO(2) venting the extent of the H-bonding between PEG and PVP reappeared. The extent of H-bonding recovery was greatest for blends with low M(w) PEG (M(w): 4×10(2)) and PVP (M(w): 9×10(3)) and PEG content ≥0.54 wt% under mild conditions of pressure (80 bar) and temperature (35°C). For the same low M(w) blends, increasing pressure to 150 bar, or temperature to 50°C, showed poor H-bond recovery upon CO(2) venting. Overall, it was shown that supercritical CO(2)-induced shielding of H-bonding interactions in polymer blends is reversible upon CO(2) venting, and the magnitude of both was influenced by processing conditions and blend composition. Copyright © 2011 Elsevier B.V. All rights reserved.

  4. PVP-SDS软模板引导常温水相一锅法合成银纳米棒%Aqueous Synthesis of Silver Nanorods at Normal Temperature in One-pot Directed by Soft Templates of PVP-SDS

    Institute of Scientific and Technical Information of China (English)

    方云; 吴梦洁; 任月萍; 江明

    2011-01-01

    Uniform multiply twinned particles(MTP) of nanosilver were synthesized in polyvinylpyrroli-done(PVP) and sodium dodecyl sulfate(SDS) aggregations soft template solution by using ammoniacal sil-ver ions as reaction precursor and glucose as reducing agent.Subsequently,the MTP which were(50±5) nm in diameter spontaneously grew into silver nanorods.The surface plasma resonance peak of these silver MTP appeared at 441 nm and their XRD diffraction pattern revealed that they were face-centric structure(fcc) with the strongest diffraction peak at the(111) lattice plane.The lattice fringes and twin planes of the MTP were observed by the high-resolution transmission electron microscopy(HRTEM) and the quintuple twinned structure of the MTP was further validated by the selected area electron diffraction(SAED).It is deduced that the as-prepared MTP of nanosilver with high growth activities could further grow induced by the PVP-SDS template.Eventually,anisotropy silver nanorods were simply prepared in one-pot by virtue of the restricted Ostwald ripening assisted by PVP-SDS soft template at normal temperature.This is a novel route instead of the conventional polyol-assisted and crystal seed-induced hyperthernal methods,which could evidently increase the applicability of the wet-chemical methods and markedly reduce the cost to pre-pare one-dimensional nanosilver materials.%以银氨络离子为前躯体,葡萄糖为还原剂,在聚乙烯吡咯烷酮(PVP)和十二烷基硫酸钠(SDS)组成的软模板中反应,首先得到形貌均一、粒径为(50±5)nm的纳米银颗粒,随后自发生长成银纳米棒.测试结果表明纳米银颗粒的等离子共振吸收峰在441 nm处,XRD表明其为面心立方体,在(111)晶面有最强吸收;高分辨透射电镜(HRTEM)观察到的晶格条纹和孪晶面证实其为多重孪晶(MTP),选区电子衍射(SAED)进一步证实了其具有五重孪晶结构.由于孪晶结构具

  5. Study on plasma pre-functionalized PVC film grafted with TiO2/PVP to improve blood compatible and antibacterial properties

    Science.gov (United States)

    Suganya, Arjunan; Shanmugavelayutham, Gurusamy; Serra Rodríguez, Carmen

    2017-04-01

    Research into the design of new biopolymers/polymer functionalized with nanoparticles is of tremendous interest to the medical sector, particularly with regard to blood-contacting devices. In this present study, a steady blood compatible and active antibacterial coating was fabricated by the grafting of titanium dioxide (TiO2)/polyvinylpyyrolidone (PVP) onto a polyvinyl chloride (PVC) film surface via the direct-current glow discharge plasma method. To enhance the chemical interaction between TiO2/PVP and PVC, the surfaces of the PVC films were functionalized by different plasmas (air, argon, and oxygen) before coating. In this study, the plasma parameters were varied, such as treatment time of about 5–20 min for a constant power of 100 W, potential 300 V, and a constant gas pressure of 2 Pa for air, argon, and oxygen gas environment. Then, the different plasma treatments on the PVC films, TiO2/PVP were grafted using a simple dip-coating method. In addition, the TiO2/PVP-grafted PVC films were characterized by contact angle, attenuated total reflectance Fourier transform infrared spectroscopy, field-emission scanning electron microscope, and x-ray photo electron spectroscopy. Importantly, TiO2/PVP is grafted onto the PVC surface due to the plasma-based retained functionality and demonstrates adhesive efficiency, which was observed by XPS. The bio-stability of the TiO2/PVP-modified PVC film was evaluated by in vitro platelet activation analysis and protein adsorption analysis. Then, the antibacterial properties were evaluated by the agar diffusion method against Escherichia coli. The result reveals that the grafting of TiO2/PVP was slightly higher for the 15 min oxygen plasma-functionalized PVC, which significantly decreases the platelet adhesion and protein adsorption. Moreover, the antibacterial properties of the 15 min oxygen plasma-functionalized PVC with TiO2/PVP-grafted film is also greatly improved compared with an air- and argon

  6. Anti-inflammatory effects of silver-polyvinyl pyrrolidone (Ag-PVP nanoparticles in mouse macrophages infected with live Chlamydia trachomatis

    Directory of Open Access Journals (Sweden)

    Yilma AN

    2013-07-01

    Full Text Available Abebayehu N Yilma, Shree R Singh, Saurabh Dixit, Vida A DennisCenter for Nanobiotechnology and Life Sciences Research, Alabama State University, Montgomery, AL, USAAbstract: Chlamydia trachomatis is a very common sexually transmissible infection in both developing and developed countries. A hallmark of C. trachomatis infection is the induction of severe inflammatory responses which play critical roles in its pathogenesis. Antibiotics are the only treatment option currently available for controlling C. trachomatis infection; however, they are efficacious only when administered early after an infection. The objectives of this study are to explore alternative strategies in the control and regulation of inflammatory responses triggered by a C. trachomatis infection. We employed silver-polyvinyl pyrrolidone (Ag-PVP nanoparticles, which have been shown to possess anti-inflammatory properties, as our target and the in vitro mouse J774 macrophage model of C. trachomatis infection. Our hypothesis is that small sizes of Ag-PVP nanoparticles will control inflammatory mediators triggered by a C. trachomatis infection. Cytotoxicity studies using Ag-PVP nanoparticles of 10, 20, and 80 nm sizes revealed >80% macrophage viability up to a concentration of 6.25 µg/mL, with the 10 nm size being the least toxic. All sizes of Ag-PVP nanoparticles, especially the 10 nm size, reduced the levels of the prototypic cytokines, tumor necrosis factor (TNF and interleukin (IL-6, as elicited from C. trachomatis infected macrophages. Additionally, Ag-PVP nanoparticles (10 nm selectively inhibited a broad spectrum of other cytokines and chemokines produced by infected macrophages. Of significance, Ag-PVP nanoparticles (10 nm caused perturbations in a variety of upstream (toll like receptor 2 [TLR2], nucleotide-binding oligomerization-protein 2 [NOD2], cluster of differentiation [CD]40, CD80, and CD86 and downstream (IL-1 receptor-associated kinase 3 [IRAK3] and matrix

  7. Enhanced DSSCs efficiency via Cooperate co-absorbance (CdS QDs) and plasmonic core-shell nanoparticle (Ag@PVP)

    Science.gov (United States)

    Amiri, Omid; Salavati-Niasari, Masoud; Bagheri, Samira; Yousefi, Amin Termeh

    2016-05-01

    This paper describes cooperate the co-absorbance (CdS QDs) and the plasmonic core-shell nanoparticles (Ag@PVP) of dye synthesized solar cells in which CdS QDs and Ag@PVP are incorporated into the TiO2 layer. Cooperative nanoparticles show superior behavior on enhancing light absorption in comparison with reference cells. Cooperated DSSC exhibits the best performance with the power conversion efficiency of 7.64% which is superior to that of the free–modified DSSC with the PCE of 5%. Detailed studies offer an effective approach to enhance the efficiency of dye synthesized solar cells.

  8. Anti-inflammatory effects of silver-polyvinyl pyrrolidone (Ag-PVP) nanoparticles in mouse macrophages infected with live Chlamydia trachomatis.

    Science.gov (United States)

    Yilma, Abebayehu N; Singh, Shree R; Dixit, Saurabh; Dennis, Vida A

    2013-01-01

    Chlamydia trachomatis is a very common sexually transmissible infection in both developing and developed countries. A hallmark of C. trachomatis infection is the induction of severe inflammatory responses which play critical roles in its pathogenesis. Antibiotics are the only treatment option currently available for controlling C. trachomatis infection; however, they are efficacious only when administered early after an infection. The objectives of this study are to explore alternative strategies in the control and regulation of inflammatory responses triggered by a C. trachomatis infection. We employed silver-polyvinyl pyrrolidone (Ag-PVP) nanoparticles, which have been shown to possess anti-inflammatory properties, as our target and the in vitro mouse J774 macrophage model of C. trachomatis infection. Our hypothesis is that small sizes of Ag-PVP nanoparticles will control inflammatory mediators triggered by a C. trachomatis infection. Cytotoxicity studies using Ag-PVP nanoparticles of 10, 20, and 80 nm sizes revealed >80% macrophage viability up to a concentration of 6.25 μg/mL, with the 10 nm size being the least toxic. All sizes of Ag-PVP nanoparticles, especially the 10 nm size, reduced the levels of the prototypic cytokines, tumor necrosis factor (TNF) and interleukin (IL)-6, as elicited from C. trachomatis infected macrophages. Additionally, Ag-PVP nanoparticles (10 nm) selectively inhibited a broad spectrum of other cytokines and chemokines produced by infected macrophages. Of significance, Ag-PVP nanoparticles (10 nm) caused perturbations in a variety of upstream (toll like receptor 2 [TLR2], nucleotide-binding oligomerization-protein 2 [NOD2], cluster of differentiation [CD]40, CD80, and CD86) and downstream (IL-1 receptor-associated kinase 3 [IRAK3] and matrix metallopeptidase 9 [MMP9]) inflammatory signaling pathways by downregulating their messenger ribonucleic acid (mRNA) gene transcript expressions as induced by C. trachomatis in macrophages

  9. Preparation of Size-tunable, Highly Monodisperse PVP-Protected Pt-nanoparticles by Seed-mediated Growth

    Energy Technology Data Exchange (ETDEWEB)

    Koebel, Matthias Michael; Jones, Louis C.; Somorjai, Gabor A.

    2008-04-02

    We demonstrate a preparative method which produces highly-monodisperse Pt-nanoparticles of tunable size without the external addition of seed particles. Hexachloroplatinic acid is dosed slowly to an ethylene glycol solution at 120 C and reduced in the presence of a stabilizing polymer poly-N-vinylpyrollidone (PVP). Slow addition of the Pt-salt first will first lead to the formation of nuclei (seeds) which then grow further to produce larger particles of any desired size between 3 and 8nm. The amount of added hexachloroplatinic acid precursor controls the size of the final nanoparticle product. TEM was used to determine size and morphology and to confirm the crystalline nature of the nanoparticles. Good reproducibility of the technique was demonstrated. Above 7nm, the particle shape and morphology changes suddenly indicating a change in the deposition selectivity of the Pt-precursor from (100) towards (111) crystal faces and breaking up of larger particles into smaller entities.

  10. Study of interaction of ethylene glycol/PVP phase on noble metal powders prepared by polyol process

    Indian Academy of Sciences (India)

    F Bonet; K Tekaia-Elhsissen; K Vijaya Sarathy

    2000-06-01

    Noble metal powders (Au, Ag, Pt, Pd and Ru) have been synthesized by the polyol process in both the nanometer and submicron scales (sans Pd, Pt and Ru). They have been characterized by both microscopic (TEM and SEM) as well as spectroscopic techniques (FT-IR and XPS). Infrared spectroscopy was employed to study the colloid particles in the presence of ethylene glycol and PVP and the results show that the interaction between the organic phase and the metal particles vary according to the particle size. The role of the solvent, ethylene glycol, during the reduction process was also investigated and we observe formation of >C=O vibration band after the reduction process implying that the solvent reduces the metal ions thereby getting oxidized. XPS measurements carried out on the colloidal sols have shown the presence of the organic phase adsorbed onto the metal particles.

  11. Influence of Copolymer Composition on In Vitro and In Vivo Performance of Celecoxib-PVP/VA Amorphous Solid Dispersions

    DEFF Research Database (Denmark)

    Knopp, Matthias Manne; Nguyen, Julia Hoang; Mu, Huiling;

    2016-01-01

    Previous studies suggested that an amorphous solid dispersion with a copolymer consisting of both hydrophobic and hydrophilic monomers could improve the dissolution profile of a poorly water-soluble drug compared to the crystalline form. Therefore, this study investigated the influence...... of the copolymer composition of polyvinylpyrrolidone/vinyl acetate (PVP/VA) on the non-sink in vitro dissolution behavior and in vivo performance of celecoxib (CCX) amorphous solid dispersions. The study showed that the hydrophilic monomer vinylpyrrolidone (VP) was responsible for the generation of CCX...... water-soluble drug as an amorphous solid dispersion using a copolymer, the copolymer composition has a significant influence on the dissolution profile and in vivo performance. Thus, the dissolution profile of a drug can theoretically be tailored by changing the monomer ratio of a copolymer with respect...

  12. Acid and base recovery from brine solution using PVP intermediate-based bipolar membrane through water splitting technology

    Science.gov (United States)

    Venugopal, Krishnaveni; Murugappan, Minnoli; Dharmalingam, Sangeetha

    2017-07-01

    Potable water has become a scarce resource in many countries. In fact, the world is not running out of water, but rather, the relatively fixed quantity is becoming too contaminated for many applications. Hence, the present work was designed to evaluate the desalination efficiency of resin and glass fiber-reinforced Polysulfone polymer-based monopolar and bipolar (BPM) ion exchange membranes (with polyvinyl pyrrolidone as the intermediate layer) on a real sample brine solution for 8 h duration. The prepared ion exchange membranes (IEMs) were characterized using FTIR, SEM, TGA, water absorption, and contact angle measurements. The BPM efficiency, electrical conductivity, salinity, sodium, and chloride ion concentration were evaluated for both prepared and commercial-based IEM systems. The current efficiency and energy consumption values obtained during BPMED process were found to be 45 % and 0.41 Wh for RPSu-PVP-based IEM system and 38 % and 1.60 Wh for PSDVB-based IEM system, respectively.

  13. PVP-coated silver nanoparticles and silver ions induce reactive oxygen species, apoptosis and necrosis in THP-1 monocytes

    DEFF Research Database (Denmark)

    Foldbjerg, Rasmus; Olesen, Ping Liu; Hougaard, Mads

    2009-01-01

    the effect of well characterized, PVP-coated Ag NPs (69 nm ± 3 nm) and Ag+ in a human monocytic cell line (THP-1). Characterization of the Ag NPs was conducted in both stock suspension and cell media with or without serum and antibiotics. By using the flowcytometric annexin V/propidium iodide (PI) assay......The objective of the present study was to investigate the toxicity of silver nanoparticles (Ag NPs) in vitro. Silver ions (Ag+) have been used in medical treatments for decades whereas Ag NPs have been used in a variety of consumer products within recent years. This study was undertaken to compare......, both Ag NPs and Ag+ were shown to induce apoptosis and necrosis in THP-1 cells depending on dose and exposure time. Furthermore, the presence of apoptosis could be confirmed by the TUNEL method. A number of studies have implicated the production of reactive oxygen species (ROS) in cytotoxicity mediated...

  14. Spectroscopic Study of the Thermal Degradation of PVP-capped Rh and Pt Nanoparticles in H2 and O2 Environments

    Energy Technology Data Exchange (ETDEWEB)

    Borodko, Yuri; Lee, Hyun Sook; Joo, Sang Hoon; Zhang, Yawen; Somorjai, Gabor A.

    2009-09-15

    Poly(N-vinylpyrrolidone) (PVP) capped platinum and rhodium nanoparticles (7-12 nm) have been studied with UV-VIS, FTIR and Raman spectroscopy. The absorption bands in the region 190-900 nm are shown to be sensitive to the electronic structure of surface Rh and Pt atoms as well as to the aggregation of the nanoparticles. In-situ FTIR-DRIFT spectroscopy of the thermal decay of PVP stabilized Rh and Pt nanoparticles in H{sub 2} and O{sub 2} atmospheres in temperatures ranging from 30 C-350 C reveal that decomposition of PVP above 200 C, PVP transforms into a 'polyamidpolyene' - like material that is in turn converted into a thin layer of amorphous carbon above 300 C. Adsorbed carbon monoxide was used as a probing molecule to monitor changes of electronic structure of surface Rh and Pt atoms and accessible surface area. The behavior of surface Rh and Pt atoms with ligated CO and amide groups of pyrrolidones resemble that of surface coordination compounds.

  15. In vitro Phase I and Phase II metabolism of α-pyrrolidinovalerophenone (α-PVP), methylenedioxypyrovalerone (MDPV) and methedrone by human liver microsomes and human liver cytosol.

    Science.gov (United States)

    Negreira, Noelia; Erratico, Claudio; Kosjek, Tina; van Nuijs, Alexander L N; Heath, Ester; Neels, Hugo; Covaci, Adrian

    2015-07-01

    The aim of the present study was to identify the in vitro Phase I and Phase II metabolites of three new psychoactive substances: α-pyrrolidinovalerophenone (α-PVP), methylenedioxypyrovalerone (MDPV), and methedrone, using human liver microsomes and human liver cytosol. Accurate-mass spectra of metabolites were obtained using liquid chromatography-quadrupole time-of-flight mass spectrometry. Six Phase I metabolites of α-PVP were identified, which were formed involving reduction, hydroxylation, and pyrrolidine ring opening reactions. The lactam compound was the major metabolite observed for α-PVP. Two glucuronidated metabolites of α-PVP, not reported in previous in vitro studies, were further identified. MDPV was transformed into 10 Phase I metabolites involving reduction, hydroxylation, and loss of the pyrrolidine ring. Also, six glucuronidated and two sulphated metabolites were detected. The major metabolite of MDPV was the catechol metabolite. Methedrone was transformed into five Phase I metabolites, involving N- and O-demethylation, hydroxylation, and reduction of the ketone group. Three metabolites of methedrone are reported for the first time. In addition, the contribution of individual human CYP enzymes in the formation of the detected metabolites was investigated.

  16. Antimicrobial activity of PVP from an Antarctic bacterium, Janthinobacterium sp. Ant5-2, on multi-drug and methicillin resistant Staphylococcus aureus

    KAUST Repository

    Huang, Jonathan P.

    2012-04-11

    Multiple drug resistant (MDR) and methicillin-resistant Staphylococcus aureus (MRSA) have become increasingly prevalent as a community acquired infection. As a result limited treatment options are available with conventional synthetic antibiotics. Bioprospecting natural products with potent antimicrobial activity show promise for developing new drugs against this pathogen. In this study, we have investigated the antimicrobial activity of a purple violet pigment (PVP) from an Antarctic bacterium, Janthinobacterium sp. Ant5-2 on 15 clinical MDR and MRSA strains. The colorimetric resazurin assay was employed to determine the minimum inhibitory concentration (MIC90) of PVP against MDR and MRSA. The MIC90 ranged between 1.57 µg/mL and 3.13 µg/mL, which are significantly lower than many antimicrobials tested from natural sources against this pathogen. The spectrophotometrically determined growth analysis and total microscopic counts using Live/dead® BacLight™ fluorescent stain exhibited a steady decrease in viability of both MDR and MRSA cultures following treatment with PVP at the MIC levels. In silico predictive molecular docking study revealed that PVP could be a DNA-targeting minor groove binding antimicrobial compound. The continued development of novel antimicrobials derived from natural sources with the combination of a suite of conventional antibiotics could stem the rising pandemic of MDR and MRSA along with other deadly microbial pathogens.

  17. Ferroelectric PLZT thick films grown by poly(1-vinylpyrrolidone-co-vinyl acetate) (PVP/VA)-modified sol-gel process

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Zhongqiang; Ma, Beihai; Li, Meiya; Koritala, Rachel E.; Balachandran, Uthamalingam

    2016-03-01

    We report the growth of ferroelectric Pb0.92La0.08Zr0.52Ti0.48O3 (PLZT) thick films using a poly(1-vinylpyrrolidone-co-vinyl acetate) (PVP/VA)-modified sol–gel process. A per-coating thickness of ≈0.66 μm has been demonstrated using PVP/VA-modified solution, which is more than doubled that of the PLZT films grown by PVP-modified method, and nearly 6 times the per-coating thickness of films prepared by conventional sol–gel process. PLZT thick films grown on LNO/Ni substrates exhibited denser microstructure, higher remanent polarization (11 μC/cm2) and dielectric tunability (45%), lower leakage current density (≈1.2 × 10-8 A/cm2), and higher breakdown strength (≈1.6 MV/cm) than those for the samples grown on PtSi substrates. These results demonstrated great potential of using PVP/VA-modified sol–gel process for high power film capacitor applications.

  18. Effect of PVP on the characteristic of modified membranes made from waste PET bottles for humic acid removal [version 2; referees: 2 approved

    Directory of Open Access Journals (Sweden)

    Nasrul Arahman

    2017-06-01

    Full Text Available Background: The aim of the present study was to evaluate the possibility of using recycled polymer (waste polyethylene terephthalate [PET] bottles as a membrane material. Furthermore, the effect of the addition of a pore-forming agent and preparation conditions was also observed. Methods: Porous polymeric membranes were prepared via thermally induced phase separation by dissolving recycled PET in phenol. PET polymer was obtained from waste plastic bottles as a new source of polymeric material. For original PET membrane, the casting solution was prepared by dissolving of 20wt% PET in phenol solution. For PET modified membrane, a 5 wt% of polyvinylpyrrolidone (PVP was added into polymer solution. The solution was cast onto a glass plate at room temperature followed by evaporation before the solidification process. The membranes formed were characterized in terms of morphology, chemical group, and filtration performance. A humic acid solution was used to identify the permeability and the solute rejection of the membranes. Results: The results showed that the recycled PET from waste plastic bottles was applicable to use as a membrane material for a water treatment process. The maximum flux of 97.0 l/m2.hr was obtained from filtration test using PET membrane. The highest rejection of humic acid in a water sample, which reached up to 75.92%, was obtained using the PET/PVP membrane. Conclusions: The recycled PET from waste bottles was successfully used to prepare porous membrane. The membrane was modified by the addition of PVP as a membrane modifying agent. SEM analysis confirmed that the original PET membrane has a rough and large pore structure. The addition of PVP improved the pore density with a narrow pore structure. The PET/PVP membrane conditioned with evaporation was the best in humic acid rejection.

  19. Energy transfer based photoluminescence spectra of (Tb{sup 3+}+ Sm{sup 3+}):PEO+PVP polymer nano-composites with Ag nano-particles

    Energy Technology Data Exchange (ETDEWEB)

    Naveen Kumar, K., E-mail: knaveenphy@gmail.com; Chandra Babu, B.; Buddhudu, S.

    2015-05-15

    Sm{sup 3+}:PEO+PVP, Sm{sup 3+}+Tb{sup 3+}:PEO+PVP and Sm{sup 3+}+Tb{sup 3+}+Ag NPs:PEO+PVP polymer films have successfully been synthesized by a solution casting method. For these polymer films, their XRD, FTIR and RAMAN spectral profiles have been analyzed. Both absorption and photoluminescence spectra have been measured in evaluating their optical properties. The Sm{sup 3+}:PEO+PVP polymer film has displayed a reddish-orange emission at 600 nm under an UV lamp and its absorption and emission spectra have also been measured to evaluate its optical characteristics. A reddish-orange emission at 600 nm ({sup 4}G{sub 5/2}→ {sup 6}H{sub 7/2}) of Sm{sup 3+} has been measured for which lifetime has also been evaluated suitably. The Photoluminescence efficiency of Sm{sup 3+} ion has been enhanced due to the addition of Tb{sup 3+} by means of an energy transfer process. The energy transfer mechanism, from Tb{sup 3+} to Sm{sup 3+} has been explained. In Ag nano-filler embedded in Tb{sup 3+}+Sm{sup 3+}:PEO+PVP polymer system, a different energy transfer process which exists between Ag nano-particles and Sm{sup 3+} ions also taking place in the polymer matrix has been identified. From these results, these films could be suggested as potential reddish-orange luminescent optical materials.

  20. The formation of α-phase SnS nanorods by PVP assisted polyol synthesis: Phase stability, micro structure, thermal stability and defects induced energy band transitions

    Energy Technology Data Exchange (ETDEWEB)

    Baby, Benjamin Hudson; Mohan, D. Bharathi, E-mail: d.bharathimohan@gmail.com

    2017-05-01

    We report the formation of single phase of SnS nanostructure through PVP assisted polyol synthesis by varying the source concentration ratio (Sn:S) from 1:1M to 1:12M. The effect of PVP concentration and reaction medium towards the preparation of SnS nanostructure is systematically studied through confocal Raman spectrometer, X-ray diffraction, thermogravimetry analysis, scanning electron microscope, transmission electron microscopy, X-ray photoelectron spectroscopy, UV–Vis–NIR absorption and fluorescence spectrophotometers. The surface morphology of SnS nanostructure changes from nanorods to spherical shape with increasing PVP concentration from 0.15M to 0.5M. Raman analysis corroborates that Raman active modes of different phases of Sn-S are highly active when Raman excitation energy is slightly greater than the energy band gap of the material. The presence of intrinsic defects and large number of grain boundaries resulted in an improved thermal stability of 20 °C during the phase transition of α-SnS. Band gap calculation from tauc plot showed the direct band gap of 1.5 eV which is attributed to the single phase of SnS, could directly meet the requirement of an absorber layer in thin film solar cells. Finally, we proposed an energy band diagram for as synthesized single phase SnS nanostructure based on the experimental results obtained from optical studies showing the energy transitions attributed to band edge transition and also due to the presence of intrinsic defects. - Highlights: • PVP stabilizes the orthorhombic (α) phase of SnS. • Optical band gap of P type SnS tuned by PVP for photovoltaic applications. • The formation of Sn rich SnS phase is investigated through XPS analysis. • Intrinsic defects enhance the thermal stability of α-SnS. • The feasibility of energy transition liable to point defects is discussed.

  1. The influence of KrF excimer laser irradiation on the surface of collagen and collagen/PVP films

    Directory of Open Access Journals (Sweden)

    M. Wisniewski

    2006-01-01

    Full Text Available The surface properties of collagen and collagen/poly(vinyl pyrrolidone (PVP films after KrF excimer laser irradiation (λ=248nm were investigated by means of the technique of scanning electron microscopy (SEM and optical microscopy (OM. The laser irradiation of the used specimens caused an expansion of materials above their surface with pronounced sings of its melting. The height of the ablated volume in a case of collagen film at a fluence of 1.1J/cm2 was approximately 5μm. A white damage appears on the treated surfaces at a threshold of 0.5J/cm2 with a single pulse and becomes more visible for a higher fluence. It is also noteworthy that along with increasing fluences (beginning from the fluence of 1.7J/cm2, the characteristic filaments at the spot edges are observed. The local heat and pressure generated by the laser radiation were able to induce bubble formation on the surface. Further bubble colliding and bursting produce a three-dimensional polymer “microfoam” structure with interconnected pores. These results can be of interest for some new applications.

  2. The Effect of PEI and PVP-Stabilized Gold Nanoparticles on Equine Platelets Activation: Potential Application in Equine Regenerative Medicine

    Directory of Open Access Journals (Sweden)

    Mateusz Hecold

    2017-01-01

    Full Text Available The aim of this work was to assess the effect of different stabilizing agents, for example, polyethylenimine (PEI and polyvinylpyrrolidone (PVP, on gold nanoparticles (AuNPs and their influence on equine platelet activation and release of particular growth factors. The gold nanoparticles were produced by chemical reduction of chloroauric acid. UV-Vis spectroscopy confirmed the presence of gold nanoparticles in investigated solutions. The AuNPs were incubated with whole blood at various concentrations. The morphology of platelets in PRP prepared from the blood incubated with AuNPs was characterized by scanning transmission electron microscopy, whereas the concentrations of growth factors and cytokines were evaluated by ELISA assays. The most promising results were obtained with equine platelets incubated with 5% AuNPs stabilized by PEI, which lead to secretion of bone morphogenetic protein 2 (BMP-2, vascular endothelial growth factor (VEGF, and fibroblast growth factor 1 (FGF-1 and simultaneously cause decrease in concentration of interleukin-1 alpha (IL-1α. The qRT-PCR confirmed ELISA test results. The incubation with 5% AuNPs stabilized by PEI leads to upregulation of BMP-2 and VEGF transcripts of mRNA level and to downregulating expression of interleukin-6 (IL-6. Obtained data shed a promising light on gold nanoparticle application for future regenerative medicine application.

  3. Real-Time Characterization of Electrospun PVP Nanofibers as Sensitive Layer of a Surface Acoustic Wave Device for Gas Detection

    Directory of Open Access Journals (Sweden)

    D. Matatagui

    2014-01-01

    Full Text Available The goal of this work has been to study the polyvinylpyrrolidone (PVP fibers deposited by means of the electrospinning technique for using as sensitive layer in surface acoustic wave (SAW sensors to detect volatile organic compounds (VOCs. The electrospinning process of the fibers has been monitored and RF characterized in real time, and it has been shown that the diameters of the fibers depend mainly on two variables: the applied voltage and the distance between the needle and the collector, since all the electrospun fibers have been characterized by a scanning electron microscopy (SEM. Real-time measurement during the fiber coating process has shown that the depth of penetration of mechanical perturbation in the fiber layer has a limit. It has been demonstrated that once this saturation has been reached, the increase of the thickness of the fibers coating does not improve the sensitivity of the sensor. Finally, the parameters used to deposit the electrospun fibers of smaller diameters have been used to deposit fibers on a SAW device to obtain a sensor to measure different concentrations of toluene at room temperature. The present sensor exhibited excellent sensitivity, good linearity and repeatability, and high and fast response to toluene at room temperature.

  4. Microwave-assisted polyol synthesis and characterization of pvp-capped cds nanoparticles for the photocatalytic degradation of tartrazine

    Energy Technology Data Exchange (ETDEWEB)

    Darwish, Maher, E-mail: m-darwish@razi.tums.ac.ir [Department of Drug and Food Control, Faculty of Pharmacy, Tehran University of Medical Sciences, Tehran (Iran, Islamic Republic of); Mohammadi, Ali, E-mail: alimohammadi@tums.ac.ir [Department of Drug and Food Control, Faculty of Pharmacy, Tehran University of Medical Sciences, Tehran (Iran, Islamic Republic of); Nanotechnology Research Centre, Faculty of Pharmacy, Tehran University of Medical Sciences, Tehran (Iran, Islamic Republic of); Assi, Navid, E-mail: navid_a30@yahoo.com [Department of Drug and Food Control, Faculty of Pharmacy, Tehran University of Medical Sciences, Tehran (Iran, Islamic Republic of)

    2016-02-15

    Highlights: • PVP-stabilized CdS nanoparticles have been fabricated by a polyol-microwave method. • CdS nanoparticles were characterized and the size was approximately 48 ± 10 nm. • Catalytic activity of our nanoparticles was examined for tartrazine degradation. • Remarkable results were obtained under both UV and visible light irradiations. - Abstract: Polyvinylpyrrolidone capped cadmium sulfide nanoparticles have been successfully synthesized by a facile polyol method with ethylene glycol. Microwave irradiation and calcination were used to control the size and shape of nanoparticles. Characterization with scanning electron microscopy revealed a restricted nanoparticles growth comparing with the uncapped product, hexagonal phase and 48 nm average particle size were confirmed by X-ray diffraction, and finally mechanism of passivation was suggested depending on Fourier transform infrared spectra. The efficiency of nanoparticles was evaluated by the photocatalytic degradation of tartrazine in aqueous solution under UVC and visible light irradiation. Complete degradation of the dye was observed after 90 min of UVC irradiation under optimized conditions. Kinetic of reaction fitted well to the pseudo-first-order kinetic and Langmuir–Hinshelwood models. Furthermore, 85% degradation of the dye in 9 h under visible light suggests that cadmium sulfide is a promising tool to work under visible light for environmental remediation.

  5. Investigations of UV photolysis of PVP-capped silver nanoparticles in the presence and absence of dissolved organic carbon

    Energy Technology Data Exchange (ETDEWEB)

    Poda, Aimee R., E-mail: aimee.r.poda@usace.army.mil; Kennedy, Alan J.; Cuddy, Michael F., E-mail: michael.cuddy@usace.army.mil; Bednar, Anthony J. [U.S. Army Engineer Research and Development Center, Environmental Laboratory (United States)

    2013-05-15

    This study investigated the effect of UV irradiation on the characteristics and toxicity of 50 nm (nominal diameter) polyvinylpyrrolidone-capped silver nanoparticles (AgNPs) in the presence and absence of dissolved organic carbon (DOC). The photolysis resulted in a decrease in average particle size as measured by field flow fractionation interfaced with inductively coupled plasma mass spectrometry. The decrease in size was attributed to the photo-induced oxidation of the PVP and dissolution of metallic silver. Moreover, photolysis of the AgNPs in solutions containing DOC appeared to give rise to small nanoparticles ({approx}5 nm) formed via reduction of dissolved silver ions. These results were consistent with photolysis of AgNO{sub 3} solutions initially devoid of nanoparticles. Thus, the carbon-containing constituents of DOC serve as reducing agents for Ag{sup +}, primarily under conditions of UV irradiation. The standard zooplankton model, Daphnia magna, indicated that the toxicity of nanosilver was significantly reduced when the AgNPs have been exposed to UV light. Observed toxicity was further reduced when AgNPs in DOC-containing solutions were exposed to UV. These results suggest that environmentally relevant conditions such as DOC and UV light are important mitigating factors that mediate the aquatic toxicity of AgNPs.

  6. Observations on PVP-protected noble metallic nanoparticle deposits upon heating via in situ synchrotron radiation X-ray diffraction.

    Science.gov (United States)

    Song, Jenn-Ming; Chiou, Guan-Di; Chen, Wei-Ting; Chen, Shih-Yun; Kao, Tzu-Hsuan; Chen, In-Gann; Lee, Hsin-Yi

    2011-03-21

    Through monitoring the evolution of the X-ray diffraction peaks, the phase transformation of PVP-protected Ag and Au nanoparticle deposits (NPDs) on electronic substrates of Cu and Ni upon heating in air was investigated via in situ synchrotron radiation X-ray diffraction. With an increasing temperature, the broad diffraction peak of nano-sized Ag and Au particles with the original average diameters of 4.2 nm and 9.6 nm, respectively, became sharp because of particle coarsening and coalescence. Complex phase transitions among Au, Cu, AuCu(3) and CuO(x) were observed, mainly due to the negative enthalpy of mixing between Au and Cu. The interactions between NPDs and the substrates affected the shift of diffraction peaks to lower angles, caused by thermal expansion and also the temperature for the oxide formation. Compared to Au, Ag NPDs did not form intermetallic compounds with Cu and the formation of copper oxides can also be retarded mainly due to the phase separation feature of the Ag-Cu system.

  7. Preparation of Aligned Ultra-long and Diameter-controlled Silicon Oxide Nanotubes by Plasma Enhanced Chemical Vapor Deposition Using Electrospun PVP Nanofiber Template

    Directory of Open Access Journals (Sweden)

    Zhou Ming

    2009-01-01

    Full Text Available Abstract Well-aligned and suspended polyvinyl pyrrolidone (PVP nanofibers with 8 mm in length were obtained by electrospinning. Using the aligned suspended PVP nanofibers array as template, aligned ultra-long silicon oxide (SiOx nanotubes with very high aspect ratios have been prepared by plasma-enhanced chemical vapor deposition (PECVD process. The inner diameter (20–200 nm and wall thickness (12–90 nm of tubes were controlled, respectively, by baking the electrospun nanofibers and by coating time without sacrificing the orientation degree and the length of arrays. The micro-PL spectrum of SiOx nanotubes shows a strong blue–green emission with a peak at about 514 nm accompanied by two shoulders around 415 and 624 nm. The blue–green emission is caused by the defects in the nanotubes.

  8. Influence of polymer molecular weight on in vitro dissolution behavior and in vivo performance of celecoxib:PVP amorphous solid dispersions

    DEFF Research Database (Denmark)

    Knopp, Matthias Manne; Nguyen, Julia Hoang; Becker, Christian;

    2016-01-01

    In this study, the influence of the molecular weight of polyvinylpyrrolidone (PVP) on the non-sink in vitro dissolution and in vivo performance of celecoxib (CCX):PVP amorphous solid dispersions were investigated. The dissolution rate of CCX from the amorphous solid dispersions increased...... weight where the crystallization inhibition was strongest. Consistent with the findings from the non-sink in vitro dissolution tests, the amorphous solid dispersions with the highest molecular weight PVPs (K30 and K60) resulted in significantly higher in vivo bioavailability (AUC0-24h) compared with pure...... amorphous and crystalline CCX. A linear relationship between the in vitro and in vivo parameter AUC0-24h indicated that the simple non-sink in vitro dissolution method used in this study could be used to predict the in vivo performance of amorphous solid dispersion with good precision, which enabled...

  9. TURP and PVP treatments are really similar? From subjective feeling to objective data. Pilot study (proof of concept) prospective randomized trial.

    Science.gov (United States)

    Albino, Giuseppe; Marucco, Ettore Cirillo

    2012-12-01

    Transurethral resection of the prostate (TURP) is the gold standard of surgical treatment of the BPH. Alternative surgical techniques have been developed for patients with blood coagulation disorders secondary to anticoagulants or antiplatelet intake. The photoselective vaporization of the prostate (PVP) by Green Laser is a technique used with the aim of obtaining tissue ablation with instantaneous hemostasis. In our experience we sensed the feeling of some differences between the two technologies. For each patient, we calculated the difference (delta) between Qmax, Qmed, PMR to 6 months after surgery compared with preoperative measurements (deltaQmax, deltaQmed, deltaPMR). In the comparison between PVP and TURP the differences between the results, in terms of deltaQmax (11.04 vs. 8.9 ml/sec), deltaQmed (5.87 vs. 3.64 ml/sec), deltaPMR, are not statistically significant, therefore it is clear that if we consider the average of the results, significant differences do not come out between the two techniques. Instead, the real differences emerge from consideration of standard deviations: the higher standard deviations of Qmax and Qmed of PVP compared to TURP (8.29 vs 5.01; 5,51 vs 1.64) indicate that the final result of an intervention being performed by TURP is nearest to the expected preoperatively result; on the contrary the final result of an operation being performed by PVP shows a significantly higher variability. As regards for our clinical decision it follows that the proposal of a surgical procedure which shows the "risk" of a higher variability of the final result is justified only in cases of high cardiovascular or blood coagulation "risk".

  10. Development of PVP/PEG mixtures as appropriate carriers for the preparation of drug solid dispersions by melt mixing technique and optimization of dissolution using artificial neural networks.

    Science.gov (United States)

    Barmpalexis, Panagiotis; Koutsidis, Ioannis; Karavas, Evangelos; Louka, Dimitra; Papadimitriou, Sofia A; Bikiaris, Dimitrios N

    2013-11-01

    The effect of plasticizer's (PEG) molecular weight (MW) on PVP based solid dispersions (SDs), prepared by melt mixing, was evaluated in the present study using Tibolone as a poorly water soluble model drug. PEGs with MW of 400, 600, and 2000 g/mol were tested, and the effect of drug content, time and temperature of melt mixing on the physical state of Tibolone, and the dissolution characteristics from SDs was investigated. PVP blends with PEG400 and PEG600 were completely miscible, while blends were heterogeneous. Furthermore, a single Tg recorded in all samples, indicating that Tibolone was dispersed in a molecular lever (or in the form of nanodispersions), varied with varying PEG's molecular weight, melt mixing temperature, and drug content, while FTIR analysis indicated significant interactions between Tibolone and PVP/PEG matrices. All prepared solid dispersion showed long-term physical stability (18 months in room temperature). The extent of interaction between mixture components was verified using Fox and Gordon-Taylor equations. Artificial neural networks, used to correlate the studied factors with selected dissolution characteristics, showed good prediction ability.

  11. Nonlinear optical property and fluorescence quenching behavior of PVP capped ZnS nanoparticles co-doped with Mn{sup 2+} and Sm{sup 3+}

    Energy Technology Data Exchange (ETDEWEB)

    Prasanth, S.; Irshad, P.; Raj, D. Rithesh; Vineeshkumar, T.V. [School of Pure and Applied Physics, Mahatma Gandhi University, Kottayam, Kerala 686562 (India); Philip, Reji [Optics group, Raman Research Institute, C.V. Raman Avenue, Bangalore 560080 (India); Sudarsanakumar, C., E-mail: c.sudarsan.mgu@gmail.com [School of Pure and Applied Physics, Mahatma Gandhi University, Kottayam, Kerala 686562 (India)

    2015-10-15

    ZnS nanoparticles co-doped with different percentages of Mn{sup 2+} and Sm{sup 3+} were synthesized by the chemical co-precipitation method using polyvinylpyrrolidone (PVP) as capping agent. Cubic zinc blende phase of the samples was confirmed from X-ray diffraction. The strong interaction between PVP and ZnS nanoparticles was studied from Fourier Transform Infrared (FTIR) spectrum. The band gap values of ZnS and co-doped ZnS nanoparticles were calculated from UV‐Visible spectra. The photoluminescence spectra of pure ZnS nanoparticles showed an emission at 436 nm and when doped with Mn{sup 2+} and Sm{sup 3+} an extra peak with high intensity was observed at 596 nm. On increasing the mole percentage of dopants the intensity of the extra peak showed an enhancement until a certain concentration and then a reduction with further increase in concentration. The binding parameters were determined by Stern‐Volmer relation. The nonlinear absorption coefficients of the doped and undoped samples were calculated using Z-scan technique. - Highlights: • PVP capped ZnS nanoparticles co-doped with Mn{sup 2+} and Sm{sup 3+} were synthesized. • The band gap of ZnS and co-doped ZnS nanoparticles were determined. • On increasing the percentage of dopants quenching of PL intensity was observed. • The nonlinear absorption coefficients of the samples were investigated.

  12. PHOTOCATALYTIC HYDROGEN EVOLUTION FROM WATER SPLITTING UNDER VISIBLE LIGHT IRRADIATION ON NOVEL PHOTOCATALYST FULLENES-PVP-ZN0.999NI0.001S

    Institute of Scientific and Technical Information of China (English)

    XUE Zhixin; YANG Guipeng; CHEN Dianbao; MA Xiaomei; ZHANG Xiqin; QUAN Zhenlan

    2006-01-01

    Fullerenes (C60/C70) linked up to Ni-doped ZnS through the medium of an amphalic polymer polyvinyl pyrrolidone (PVP) to form a new kind of photocatalyst for hydrogen evolution from aqueous Na2S/Na2SO3 solution under visible light irradiation, the photocatalytic activities of this novel photocatalyst C60/C70-PVP-Zn0.999Ni0.001S are 3-5 fold higher compared with that of precurse catalyst Zn0.999Ni0.001S. This result could be attributed to Schottky barrier layer built between C60/C70 and Zn0.999Ni0.001S due to the electro-negativity of C60 and characteristic of being used as a multiple electron acceptor. C60 or C60/C70, its moiety, with its low energy first excited singlet state, is a good energy acceptor and in addition readily accepts multiple electrons, making it a potential electron accumulate as we know, which could protect the separation between electrons and holes against combination. This is an important reason for the marked increase of amount of H2 evolution during the photocatalytic process for the composite system C60/C70-PVP-Zn0.999Ni0.001S.

  13. PVP assisted hydrothermal fabrication and morphology-controllable fabrication of BiFeO{sub 3} uniform nanostructures with enhanced photocatalytic activities

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Xingfu; Mao, Weiwei [Key Laboratory for Organic Electronics & Information Displays (KLOEID), Synergetic Innovation Center for Organic Electronics and Information Displays (SICOEID), Institute of Advanced Materials - IAM, School of Materials Science and Engineering - SMSE, Nanjing University of Posts and Telecommunications - NUPT, Nanjing 210023 (China); School of Science, Advanced Energy Technology Center, Nanjing University of Posts and Telecommunications (NUPT), Nanjing 210023 (China); Zhang, Qiaoxia; Wang, Qi; Zhu, Yiyi; Zhang, Jian; Yang, Tao [Key Laboratory for Organic Electronics & Information Displays (KLOEID), Synergetic Innovation Center for Organic Electronics and Information Displays (SICOEID), Institute of Advanced Materials - IAM, School of Materials Science and Engineering - SMSE, Nanjing University of Posts and Telecommunications - NUPT, Nanjing 210023 (China); Yang, Jianping [School of Science, Advanced Energy Technology Center, Nanjing University of Posts and Telecommunications - NUPT, Nanjing 210023 (China); Li, Xing' ao, E-mail: lxahbmy@126.com [Key Laboratory for Organic Electronics & Information Displays (KLOEID), Synergetic Innovation Center for Organic Electronics and Information Displays (SICOEID), Institute of Advanced Materials - IAM, School of Materials Science and Engineering - SMSE, Nanjing University of Posts and Telecommunications - NUPT, Nanjing 210023 (China); Huang, Wei, E-mail: iamwhuang@njupt.edu.cn [Key Laboratory for Organic Electronics & Information Displays (KLOEID), Synergetic Innovation Center for Organic Electronics and Information Displays (SICOEID), Institute of Advanced Materials - IAM, School of Materials Science and Engineering - SMSE, Nanjing University of Posts and Telecommunications - NUPT, Nanjing 210023 (China); Key Laboratory of Flexible Electronics (KLOFE), Institute of Advanced Materials (IAM), National Synergistic Innovation Center for Advanced Materials - SICAM, Nanjing Tech University - NanjingTech, 30 South Puzhu Road, Nanjing 211816 (China)

    2016-08-25

    Bismuth ferrite (BiFeO{sub 3}) nanostructures with various morphologies (spindles, cubes and plates) have been successfully synthesized via a convenient one-pot hydrothermal method. The results show that three kinds of BiFeO{sub 3} products were obtained in this polyvinylpyrrolidone (PVP)-assisted hydrothermal reaction under different alkaline conditions. The resulting nanostructures were characterized using XRD and SEM. Possible formation mechanism for BiFeO{sub 3} nanostructures was proposed on the basis of our results. The experiments showed that the visible light absorptive capacity of the BiFeO{sub 3} nanostructures was significant influenced on the size and morphology. Notably, the as-prepared BiFeO{sub 3} plates with (104) facets exposed exhibit high efficiency for the degradation of methyl orange (MO) under visible light irradiation, suggesting potential applications in photocatalytic and related areas under visible light. - Highlights: • BiFeO{sub 3} nanostructures were synthesized via a PVP-assisted hydrothermal method. • The effect of the PVP and alkaline concentration was investigated. • The visible light absorptive capacity was significant influenced on the morphology. • The photocatalytic activity of the as-prepared BiFeO{sub 3} plates is the best.

  14. Förster resonance energy transfer and excited state life time reduction of rhodamine 6G with NiO nanorods in PVP films

    Science.gov (United States)

    Karthikeyan, B.

    2017-02-01

    In the present study, we report the preparation of NiO nanorods (NNR) and its Förster resonant energy transfer (FRET) behaviour with rhodamine 6G (R6G) in a Polyvinyl pyrrolidone (PVP) polymer matrix. The prepared nanocomposite polymer (NCP) films contain PVP and R6G whose concentrations are kept constant and different concentrations of NNR. Spectral overlap between the absorption and fluorescence spectrum of R6G and NNR shows the possibility of FRET phenomena to be occurring in the prepared NCP films. Steady state and time resolved fluorescence measurements are carried out at two excitation wavelengths (330 and 510 nm) to study the energy transfer process between R6G and NNR in the PVP host. The obtained results show that the energy transfer is from R6G (serves as a donor) to NNR (functions as an acceptor). Calculated radiative efficiencies, donor-acceptor distances and average lifetime also confirm the energy transfer from R6G to NNR.

  15. Assessing the Effect of PVP of Various Molecular Weight (MW in PES-Ag Membranes: Antimicrobial Study Using E.Coli

    Directory of Open Access Journals (Sweden)

    Hatijah Basri

    2011-12-01

    Full Text Available New polymeric silver (Ag composites were prepared using polyethersulfone (PES as polymer material, N-Methyl-2-pyrrolidone (NMP as solvent and polyvinylpyrollidone (PVP of various molecular weight (MW as organic fillers. Silver nitrate (AgNO3 was added by various loading in order to impart an antibacterial property to the composites. The miscibility of PES/Ag/fillers composites were characterized using TGA and any changes in chemical bonding were characterized using ATR-FTIR techniques. The XPS results showed high intensity in Eb(Ag3d range of 378.1-378.5 and 372.2-372.5 for the highest Ag loading with PVP with the highest MW. This phenomenon had altered the hydrophilicity property of composites. In this study, composites have undergone a bacteria rejection test from E.coli suspension and a domestic waste sample. Composites with highest loading of silver and highest MW of PVP (PES-Ag2P360 was observed for significantly high bacteria rejection, log reduction value (LRV~3. Therefore, PES-silver nanocomposites is a potential membrane for bacteria removal, disinfection and maybe effective for overcoming biofouling problems.

  16. Förster resonance energy transfer and excited state life time reduction of rhodamine 6G with NiO nanorods in PVP films.

    Science.gov (United States)

    Karthikeyan, B

    2017-02-15

    In the present study, we report the preparation of NiO nanorods (NNR) and its Förster resonant energy transfer (FRET) behaviour with rhodamine 6G (R6G) in a Polyvinyl pyrrolidone (PVP) polymer matrix. The prepared nanocomposite polymer (NCP) films contain PVP and R6G whose concentrations are kept constant and different concentrations of NNR. Spectral overlap between the absorption and fluorescence spectrum of R6G and NNR shows the possibility of FRET phenomena to be occurring in the prepared NCP films. Steady state and time resolved fluorescence measurements are carried out at two excitation wavelengths (330 and 510nm) to study the energy transfer process between R6G and NNR in the PVP host. The obtained results show that the energy transfer is from R6G (serves as a donor) to NNR (functions as an acceptor). Calculated radiative efficiencies, donor-acceptor distances and average lifetime also confirm the energy transfer from R6G to NNR.

  17. Melamine-(H2SO4)3 and PVP-(H2SO4)n as solid acids:Synthesis and application in the first mono- and di-nitration of bisphenol A and other phenols

    Institute of Scientific and Technical Information of China (English)

    Gholamabbas Chehardoli; Mohammad Ali Zolfigol; Seyedeh Bahareh Azimi; Ebadollah Alizadeh

    2011-01-01

    Melamine and poly vinylpyrrolidone (PVP) reacted with neat sulfuric acid readily to form two new organic solid acids namely melamine-(H2SO4)3 and PVP-(H2SO4)n. These solid acids were used for the first nitration of bisphenol A as well as other phenols in the presence of NH4NO3. Mono- and di-nitro bisphenol A have been characterized with IR and 1H NMR techniques.

  18. The effect of PVP on morphology, optical properties and electron paramagnetic resonance of Zn0.5Co0.5Fe2-xPrxO4 nanoparticles

    Science.gov (United States)

    Bitar, Z.; El-Said Bakeer, D.; Awad, R.

    2017-07-01

    Zinc Cobalt nano ferrite doped with Praseodymium, Zn0.5Co0.5Fe2-xPrxO4 (0 ≤ x ≤ 0.2), were prepared by co-precipitation method from an aqueous solution containing metal chlorides and two concentrations of poly(vinylpyrrolidone) (PVP) 0 and 30g/L as capping agent. The samples were characterized using X-ray powder diffraction (XRD), Transmission Electron Microscope (TEM), UV-visible optical spectroscopy, Fourier transform infrared (FTIR) and Electron Paramagnetic Resonance (EPR). XRD results display the formation of cubic spinel structure with space group Fd3m and the lattice parameter (a) is slightly decreased for PVP capping samples. The particle size that determined by TEM, decreases for PVP capping samples. The optical band energy Eg increases for PVP capping samples, confirming the variation of energy gap with the particle size. The FTIR results indicate that the metal oxide bands were shifted for the PVP capping samples. EPR data shows that the PVP addition increases the magnetic resonance field and hence decreases the g-factor.

  19. PVP-stabilized Ru–Rh nanoparticles as highly efficient catalysts for hydrogen generation from hydrolysis of ammonia borane

    Energy Technology Data Exchange (ETDEWEB)

    Rakap, Murat, E-mail: mrtrakap@gmail.com

    2015-11-15

    Herein, the utilization of poly(N-vinyl-2-pyrrolidone)-protected ruthenium–rhodium nanoparticles (3.4 ± 1.4 nm) as highly efficient catalysts in the hydrolysis of ammonia borane for hydrogen generation is reported. They are prepared by co-reduction of ruthenium and rhodium metal ions in ethanol/water mixture by an alcohol reduction method and characterized by transmission electron microscopy-energy dispersive X-ray spectroscopy, ultraviolet–visible spectroscopy, and X-ray photoelectron spectroscopy. They are durable and highly efficient catalysts for hydrogen generation from the hydrolysis of ammonia borane even at very low concentrations and temperature, providing average turnover frequency of 386 mol H{sub 2} (mol cat){sup −1} min{sup −1} and maximum hydrogen generation rate of 10,680 L H{sub 2} min{sup −1} (mol cat){sup −1}. Poly(N-vinyl-2-pyrrolidone)-protected ruthenium–rhodium nanoparticles also provide activation energy of 47.4 ± 2.1 kJ/mol for the hydrolysis of ammonia borane. - Highlights: • Ru-Rh@PVP NPs provide a TOF of 386 mol H{sub 2} (mol cat){sup −1} min{sup −1} for hydrolysis of AB. • Maximum HG rate is 9680 L H{sub 2} min{sup −1} (mol cat){sup −1} for the hydrolysis of AB. • Activation energy is 47.4 ± 2.1 kJ mol{sup −1} for the hydrolysis of AB.

  20. Installation of groundwater observation tubes OL-PVP36-38 and drilling of shallow drillholes OL-PP70-71 at Olkiluoto in Eurajoki 2011

    Energy Technology Data Exchange (ETDEWEB)

    Toropainen, V. [Suomen Malmi Oy, Espoo (Finland)

    2012-05-15

    In order to widen the groundwater monitoring network at Olkiluoto, Posiva Oy contracted Suomen Malmi Oy (Smoy) to install new groundwater observation tubes to three locations and to drill two shallow drillholes with standpipes. The identification numbers of the groundwater observation tubes are OL-PVP36, OL-PVP37A, 37B, 37C, OL-PVP38A, 38B, 38C and 38D, and the shallow drillholes are named OL-PP70 and OL-PP71. The observation tubes were installed and the shallow holes drilled between September 22nd and October 12th in 2011. The drilling rig used in the installation work was a GM-200 rig. Drilling equipment consisted of casing tubes (90/77 mm) with drilling bit, 55 mm geo rods and 64 mm drilling bits and T76-equipment for drilling the shallow holes. Monitoring pipes (PVC, 60/52 mm) were lowered into the holes inside the casings. The monitoring pipes consist of a lower section of riser pipe, a middle section of screen pipe and an upper section of riser pipe. The screen pipe slot size is 0.3 mm and the length of the screen section is two metres. Protective stainless steel covers with lock-up caps were installed around the monitoring tubes and the shallow drillholes. In addition to the installation of the tubes, the work included water level measurements after installation. The core samples of the shallow drillholes were logged and reported by geologist. Geological logging included the following parameters: lithology, foliation, fracture parameters, fractured zones, core loss, weathering, fracture frequency, RQD and rock quality. (orig.)

  1. Synergetic effect of TiO2 nano filler additives on conductivity and dielectric properties of PEO/PVP nanocomposite electrolytes for electrochemical cell applications

    Science.gov (United States)

    Koduru, H. K.; Kondamareddy, K. K.; Iliev, M. T.; Marinov, Y. G.; Hadjichristov, G. B.; Karashanova, D.; Scaramuzza, N.

    2017-01-01

    Sodium-ion conducting PEO/PVP blend based solid polymer electrolyte films complexed with NaIO4 salt and nano-sized TiO2 fillers are fabricated by employing a solution casting technique for Na-ion battery applications. Measurements of X-ray diffraction (XRD) and thermogravimetric analysis (TGA) are carried out to investigate the crystallinity and thermal stability of the solid polymer electrolytes. Scanning electron microscopy (SEM) and Transmission electron microscopy (TEM) studies are performed to understand the modifications in surface morphological features and to evaluate the size and distribution of dispersed nano-sized TiO2 fillers. The room temperature ionic conductivities of polymer electrolyte films are investigated by impedance analysis in the frequency range 1 MHz - 1 Hz. The nano-sized TiO2 (3 wt%) filled composite electrolyte of ‘PEO/PVP/NaIO4 (10 wt%)’ demonstrates a maximum room temperature conductivity of 9.82 X 10-6 S/cm. The influence of TiO2 filler on conductivity and dielectric properties are presented in this report.

  2. An investigation into the effect of spray drying temperature and atomizing conditions on miscibility, physical stability, and performance of naproxen-PVP K 25 solid dispersions.

    Science.gov (United States)

    Paudel, Amrit; Loyson, Yves; Van den Mooter, Guy

    2013-04-01

    The present study investigates the effect of changing spray drying temperature (40°C-120°C) and/or atomizing airflow rate (AR; 5-15 L/min) on the phase structure, physical stability, and performance of spray-dried naproxen-polyvinylpyrrolidone (PVP) K 25 amorphous solid dispersions. The modulated differential scanning calorimetry, attenuated total internal reflectance-Fourier transform infrared, and powder X-ray diffractometry (pXRD) studies revealed that higher inlet temperature (IT) or atomization airflow leads to the formation of amorphous-phase-separated dispersions with higher strongly H-bonded and free PVP fractions, whereas that prepared with the lowest IT was more homogeneous. The dispersion prepared with the lowest atomization AR showed trace crystallinity. Upon exposure to 75% relative humidity (RH) for 3 weeks, the phase-separated dispersions generated by spray drying at higher temperature or higher atomization airflow retained relatively higher amorphous drug fraction compared with those prepared at slow evaporation conditions. The humidity-controlled pXRD analysis at 98% RH showed that the dispersion prepared with highest atomization AR displayed the slowest kinetics of recrystallization. The molecular-level changes occurring during recrystallization at 98% RH was elucidated by spectroscopic monitoring at the same humidity. The rate and extent of the drug dissolution was the highest for dispersions prepared at the highest atomizing AR and the lowest for that prepared with the slowest atomizing condition.

  3. TiO2 nanowire and TiO2 nanowire doped Ag-PVP nanocomposite for antimicrobial and self-cleaning cotton textile.

    Science.gov (United States)

    Hebeish, A A; Abdelhady, M M; Youssef, A M

    2013-01-16

    The TiO(2) nanowire (TiO(2) Nw) was successfully prepared via hydrothermal method through TiO(2) nanoparticle (TiO(2) Np). TiO(2) Np doped silver and TiO(2) Nw doped silver were prepared via photo-reducing Ag(+) ions to Ag metal on the TiO(2) Np or TiO(2) Nw surfaces. The prepared nanomaterials were evaluated using X-ray (XRD) diffraction pattern, scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Bleached untreated cotton fabric and PVP treated cotton fabrics were coated with the synthesized nanomaterials using pad-dry-cure method. Photocatalytic activity of untreated and coated cotton fabrics with TiO(2) nanomaterials was investigated through the fabric self cleaning of MB dye stains. Also, the PVP finished cotton fabric modified by nanomaterials demonstrated antimicrobial activity against Gram positive bacteria, Gram negative bacteria and fungi. The mechanical properties of coated cotton fabric (tear strength, surface roughness, tensile strength and elongation at break) were examined.

  4. Electrospinning of nano-PVP and its blended fibers%静电纺纳米聚乙烯吡咯烷酮及其共混纤维的研究

    Institute of Scientific and Technical Information of China (English)

    盛冰冰; 孔庆山; 纪全; 夏延致

    2008-01-01

    采用静电法纺制出纳米聚乙烯吡咯烷酮(PVP)纤维及其共混纤维,借助旋转粘度计、电导率仪、扫描电镜(SEM)等测试表征方法,确定了纺制静电纺纳米PVP纤维的较好工艺:p(PVP)=180 g/L,纺丝电压15 kV.并研究了PvP与聚环氧乙烷(PEO)、共聚维酮S-630及聚偏氟乙烯(PVDF)的共混纺丝.结果表明,纳米PVP/PEO共混纤维的形貌较好.

  5. PREPARATION AND CHARACTERIZATION OF BACTERIAL CELLULOSE REINFORCED PVA/PVP HYDROGELS%细菌纤维素(BC)增强PVA/PVP复合水凝胶的制备及性能表征

    Institute of Scientific and Technical Information of China (English)

    李文迪; 容建华; 林志丹; 张秀菊

    2012-01-01

    Bacterial cellulose reinforced PVA/PVP double-network hydrogels with different PVA/PVP content were prepared via repeated freezing and thawing method. The structure and properties of the composite hydrogels were studied through X-ray diffraction( XRD) , infrared spectrum (IR) , scanning electron microscopy (SEM) and mechanical test. SEM results showed that PVP and PVA adsorbed evenly around the BC fiber filaments in BC/PVA/PVP hydrogels,which resulted in the fully rehydration of the composite xerogels in hot water. XRD results showed that there were significant differences between the crystallization of heat-dried and freeze-dried xerogel samples. The crystallization of both BC and PVA were better in heat-dried samples. In addition,the crystallization of BC was inhibited obviously by PVP and PVA. The effect of PVP on the crystallization of PVA in BC/PVA/PVP was similar to that in PVA/PVP hydrolgels. The mechanical test results demonstrated that the mechanical properties of the PVP/PVA hydrogels were strongly enhanced after being reinforced with the net of BC nanofibers. Furthermore, the content of PVP and PVA had an obvious effect on the mechanical properties of the composites. The dynamic viscoelasticity results also showed the strengthen effect of BC,while the elasticity of BC reinforced hydrogels decreased.%通过冷冻-熔融法制备了细菌纤维素/聚乙烯醇/聚乙烯吡咯烷酮(BC/PVA/PVP)双网络复合水凝胶,并采用X射线衍射,红外光谱,扫描电镜,力学性能测试等手段对凝胶的结构和性能进行表征.研究发现PVA、PVP通过氢键作用均匀地吸附于纤维微丝周围,将BC纤维有效地分开,因而干燥后的复合凝胶在热水中浸泡后仍可恢复原状;X射线衍射结果显示,直接干燥成膜样品和冻干样品的结晶性能差别明显,且PVA/PVP对BC的结晶有抑制作用,而BC增强复合凝胶中PVP对PVA结晶的影响作用与纯PVA/PVP体系类似,即少量PVP的存在对PVA的结

  6. Preparation of protein-loaded PLGA-PVP blend nanoparticles by nanoprecipitation method: entrapment, Initial burst and drug release kinetic studies

    Directory of Open Access Journals (Sweden)

    Shahryar Shakeri

    2015-07-01

    Full Text Available Objective(s:Despite of wide range applications of polymeric nanoparticles in protein delivery, there are some problems for the field of protein entrapment, initial burst and controlled release profile.   Materials and Methods: In this study, we investigated the influence of some changes in PLGA nanoparticles formulation to improve the initial and controlled release profile. Selected parameters were: pluronic F127, polysorbate 80 as surfactant, pH of inner aqueous phase, L/G ratio of PLGA polymer, volume of inner aqueous phase and addition of polyvinylpyrrolidone as an excipient. FITC-HSA was used as a model hydrophilic drug. The nanoparticles were prepared by nanoprecipitation.   Results:  Initial release of FITC-HSA from PLGA-tween 80 nanoparticles (opt-4, 61% was faster than control (PLGA-pluronic after 2.30 h of incubation. Results showed that decrease in pH of inner aqueous phase to pI of protein can decrease IBR but the release profile of protein is the same as control. Release profile with three phases including a initial burst b plateau and c final release phase was observed when we changed volume of inner aqueous phase and L/G ratio in formulation. Co-entrapment of HSA with PVP and pluronic reduced the IBR and controlled release profile in opt-19. Encapsulation efficiency was more than 97% and nanoparticles size and zeta potentials were mono-modal and -18.99 mV, respectively.   Conclusion:  In this research, we optimized a process for preparation of PLGA-PVP-pluronic nanoparticles of diameter less than 300 nm using nanoprecipitation method. This formulation showed a decreased initial burst and long lasting controlled release profile for FITC-HSA as a model drug for proteins.

  7. Synthesis of flower-like silver nanoparticles by polyvinyl pyrrolidone (PVP) reduction%PVP还原制备花朵状银纳米颗粒

    Institute of Scientific and Technical Information of China (English)

    何辉; 周家霆; 董红建; 宋永辉

    2013-01-01

    The flower-like silver nanoparticles were synthesized using silver nitrate (AgNO3) as precursor and poiyvinyl pyrrolidone (PVP) as reductive and protective agent. Surface characteristics of the silver nanoparticles were analyzed by UV-Vis absorption spectroscopy ( UV-vis) , Scanning Electron Microscope ( SEM ) , X-ray Diffraction (XRD) , Fourier transform infrared (FT-IR). The result showed that silver nanoparticles belong to face-centered cubic structure and with the temperature increasing, the form will transform from spherical to cubic and then to slice shape, flower-like silver nanoparticle. Ag+ in the solution would be reduced to Ag by amino N in PVP.%以硝酸银为前驱体,聚乙烯吡咯烷酮为还原剂和保护剂,制备出了花朵状纳米银.利用紫外可见吸收光谱(UV-Vis)、扫描电子显微镜(SEM)、X射线衍射仪(XRD)及傅里叶红外光谱仪(FT-IR)等对其进行了分析表征.研究表明,制得的Ag纳米颗粒属于面心立方结构,随着反应温度的升高,Ag纳米颗粒形貌由类球形到立方体形、薄片形、花朵形转变,溶液中的Ag+会得到PVP分子内酰胺基中N的给电子,使Ag+获得电子而转化为Ag.

  8. 聚乙烯吡咯烷酮成膜剂在种衣剂中的研究与应用%Research and Application of PVP Film in Seed Coating Formulation

    Institute of Scientific and Technical Information of China (English)

    胡冬松; 许勇华; 侯建宇; 陈杰

    2015-01-01

    Seed coating film PVP was prepared, and its physical and chemical properties were tested. Then difenoconazole 3%FSC was prepared with seed coating film PVP and used to coat maize seeds. The results showed that the PVP film had good physical and chemical stabilities. It could decrease the drop rate, and had no affect on seeds germination rate. The PVP film was suitable to be used for the development of excellent seed coating formulation.%配制了聚乙烯吡咯烷酮成膜剂,测试了其理化性质,并将其应用于3%苯醚甲环唑悬浮种衣剂中,考察了包衣后玉米种子的包衣脱落率和出苗率。结果表明,聚乙烯吡咯烷酮成膜剂具有良好的理化稳定性,能够降低种子包衣脱落率,不影响种子的出苗率。其适合用于开发性能优良的种衣剂。

  9. Preparation of PVP/CdS quantum dots modified electrode and its application in electroanalysis of myoglobin%PVP/CdS量子点修饰电极的制备及其对肌红蛋白的直接电化学研究

    Institute of Scientific and Technical Information of China (English)

    张莉; 刘梅川; 程欲晓; 李平; 张成林; 金利通

    2005-01-01

    该文采用溶胶-凝胶法制备了聚乙烯吡咯烷酮(PVP)表面修饰的硫化镉(CdS)半导体量子点,用透射电镜(TEM)、X射线衍射(XRD)等手段进行了表征;将其修饰在玻碳电极(GC)表面制得量子点修饰电极,并研究了肌红蛋白(Myoglobin,Mb)在该量子点修饰电极上的电化学行为.实验结果表明,PVP/CdS量子点修饰电极对肌红蛋白具有催化还原作用,且还原峰电流与被测蛋白质浓度呈良好线性关系.流动注射分析结果进一步表明该量子点修饰电极具有高的稳定性和好的重现性,检出限为2.0×10.mol/L,该电极可作为检测肌红蛋白的新型高灵敏度电化学传感器.

  10. Bioevaluation of Novel Anti-Biofilm Coatings Based on PVP/Fe3O4 Nanostructures and 2-((4-Ethylphenoxymethyl-N- (arylcarbamothioylbenzamides

    Directory of Open Access Journals (Sweden)

    Carmen Limban

    2014-08-01

    Full Text Available Novel derivatives were prepared by reaction of aromatic amines with 2-(4-ethylphenoxymethylbenzoyl isothiocyanate, affording the N-[2-(4-ethylphenoxymethyl benzoyl]-Nꞌ-(substituted phenylthiourea. Structural elucidation of these compounds was performed by IR, NMR spectroscopy and elemental analysis. The new compounds were used in combination with Fe3O4 and polyvinylpyrrolidone (PVP for the coating of medical surfaces. In our experiments, catheter pieces were coated by Matrix Assisted Pulsed Laser Evaporation (MAPLE technique. The microbial adherence ability was investigated in 6 multi-well plates by using culture based methods. The obtained surfaces were also assessed for their cytotoxicity with respect to osteoblast cells, by using fluorescence microscopy and MTT assay. The prepared surfaces by advanced laser processing inhibited the adherence and biofilm development ability of Staphylococcus aureus and Pseudomonas aeruginosa tested strains while cytotoxic effects on the 3T3-E1 preosteoblasts embedded in layer shaped alginate hydrogels were not observed. These results suggest that the obtained medical surfaces, based on the novel thiourea derivatives and magnetic nanoparticles with a polymeric shell could represent a promising alternative for the development of new and effective anti-infective strategies.

  11. PVP/Pd/IrO2/Nafion修饰微电极用于成纤维细胞中一氧化氮释放的研究%Direct Monitoring of Nitric Oxide Release from Fibrocytes with PVP/Pd/IrO2/Nafion Chemically Modified Microelectrode

    Institute of Scientific and Technical Information of China (English)

    鲜跃仲; 徐继明; 陆嘉星; 刘梅川; 蔡琪; 金利通

    2002-01-01

    采用PVP/Pd/IrO2/Nafion修饰电极对成纤维细胞中NO的释放情况进行了研究.结果表明,在正常状态下,采用NO前体L-精氨酸和乙酰胆碱对成纤维细胞进行刺激后没有NO的释放;当用脂多糖进行诱导后,则释放出高浓度的NO,加入L-精氨酸和乙酰胆碱都促进了NO的合成,而L-NNA的加入则逆转了L-精氨酸和乙酰胆碱的作用.

  12. Partially decomposed PVP as a surface modification of ZnO, CdO, ZnS and CdS nanostructures for enhanced stability and catalytic activity towards sulphamethoxazole degradation

    Indian Academy of Sciences (India)

    MAHER DARWISH; ALI MOHAMMADI; NAVID ASSI

    2017-06-01

    In order to prepare stable and efficient photocatalysts, a microwave-furnace-assisted method using ethylene glycol (EG) as a solvent has been employed to obtain metal oxides and metal sulphides nanocatalysts with partial decompositionof the polyvinylpyrrolidone (PVP) cap (P-ZnO, P-CdO, P-ZnS and P-CdS); this associates the protective functionality of PVP with enhanced catalytic activity due to effective carriers transfer. The as-produced catalysts characterization revealed an extended growth of metal oxides compared with metal sulphides, which is attributed to the competition of EG as the source of oxygen with PVP to capsulate metal oxides during the synthesis. Infrared spectra confirmed the PVP–metal complexation and partial decomposition of the polymer. Metal sulphides exhibited a better catalytic activity compared with metal oxides for sulphamethoxazole degradation in UVC light owing to their size and morphology impact; further, P-CdS induced 71% antibiotic degradation after 10 h of illumination with visible light compared with only 48% for P-ZnS, 29% for P-ZdO and 20% for P-CdO due to improved light absorption. Interestingly, around 86% degradation was induced by mixing P-CdS with P-ZnS in 80:20% ratio, indicating an enhanced visible light activity due to improved electron–hole pair separation and high redox potential of P-ZnS.

  13. Effects of additions of dimethyl siloxanes and ethylene oxide (SEO) copolymers in tensile break (Tb), in gels and swelling percentage of poly(n-vinyl-2-pyrrolidone) (PVP) crosslinking films by electron beams; Influencia da adicao dos copolimeros de dimetilsiloxano e oxido de etileno (SEO) na tensao de ruptura (Tb), na porcentagem de gel e de intumescimento de filmes de poli(n-vinil-2-pirrolidona) (PVP) reticulados por feixes de eletrons

    Energy Technology Data Exchange (ETDEWEB)

    Souza, A.; Miranda, A.; Hutzler, B.; Silva, L.G.A. [Instituto de Pesquisas Energeticas e Nucleares (IPEN), Sao Paulo, SP (Brazil); Nunes, S.P. [Universidade Estadual de Campinas, SP (Brazil). Inst. de Quimica

    1997-12-01

    When PVP gels are irradiated a self-supported film formation occur because of a crosslinking process. Such process consists of the recombination of the macro radicals during the direct or indirect interaction of ionizing radiation producing tridimensional networks. The aim of this work is to improve the tensile break (Tb) of the film without any harm to its biomedic characteristics. Thus, the SEO copolymers were chosen like coadjuvants, which show excellent hydrophilic characteristic and have been used for medical purposes. It is observed that films constituted by 6% PVP in the presence of the agar show a maximum Tb equal to 0,05 Mpa. The adding of 2,5% of the SEO in such films increase the maximum Tb to 0,08 MPa, the elevation was of 60%.It is noticed also that the increase of SEO concentration promotes an increase in the gels percentage and a decrease of the swelling percentage. So we conclude that the presence of the SEO favors the increase of crosslinking degree where 2,5% of the copolymers in films constituted by 6% of PVP and 0,4% of agar are enough to increase the Tb by 60%. (author). 13 refs., 4 figs.

  14. Acute toxicity, bioaccumulation and effects of dietary transfer of silver from brine shrimp exposed to PVP/PEI-coated silver nanoparticles to zebrafish.

    Science.gov (United States)

    Lacave, José María; Fanjul, Álvaro; Bilbao, Eider; Gutierrez, Nerea; Barrio, Irantzu; Arostegui, Inmaculada; Cajaraville, Miren P; Orbea, Amaia

    2017-09-01

    The extensive use and release to the aquatic environment of silver nanoparticles (NPs) could lead to their incorporation into the food web. Brine shrimp larvae of 24h showed low sensitivity to the exposure to PVP/PEI-coated Ag NPs (5nm), with EC50 values at 24h of 19.63mgAgL(-1), but they significantly accumulated silver after 24h of exposure to 100μgL(-1) of Ag NPs. Thus, to assess bioaccumulation and effects of silver transferred by the diet in zebrafish, brine shrimp larvae were exposed to 100ngL(-1) of Ag NPs as an environmentally relevant concentration or to 100μgL(-1) as a potentially effective concentration and used to feed zebrafish for 21days. Autometallography revealed a dose- and time-dependent metal accumulation in the intestine and in the liver of zebrafish. Three-day feeding with brine shrimps exposed to 100ngL(-1) of Ag NPs was enough to impair fish health as reflected by the significant reduction of lysosomal membrane stability and the presence of vacuolization and necrosis in the liver. However, dietary exposure to 100μgL(-1) of Ag NPs for 3days did not significantly alter gene transcription levels, neither in the liver nor in the intestine. After 21days, biological processes such as lipid transport and localization, cellular response to chemical stimulus and response to xenobiotic stimulus were significantly altered in the liver. Overall, these results indicate an effective dietary transfer of silver and point out to liver as the main target organ for Ag NP toxicity in zebrafish after dietary exposure. Copyright © 2017 Elsevier Inc. All rights reserved.

  15. Quality by design approach for developing chitosan-Ca-alginate microspheres for colon delivery of celecoxib-hydroxypropyl-β-cyclodextrin-PVP complex.

    Science.gov (United States)

    Mennini, N; Furlanetto, S; Cirri, M; Mura, P

    2012-01-01

    The aim of the present work was to develop a new multiparticulate system, designed for colon-specific delivery of celecoxib for both systemic (in chronotherapic treatment of arthritis) and local (in prophylaxis of colon carcinogenesis) therapy. The system simultaneously benefits from ternary complexation with hydroxypropyl-β-cyclodextrin and PVP (polyvinylpyrrolidone), to increase drug solubility, and vectorization in chitosan-Ca-alginate microspheres, to exploit the colon-specific carrier properties of these polymers. Statistical experimental design was employed to investigate the combined effect of four formulation variables, i.e., % of alginate, CaCl₂, and chitosan and time of cross-linking on microsphere entrapment efficiency (EE%) and drug amount released after 4h in colonic medium, considered as the responses to be optimized. Design of experiment was used in the context of Quality by Design, which requires a multivariate approach for understanding the multifactorial relationships among formulation parameters. Doehlert design allowed for defining a design space, which revealed that variations of the considered factors had in most cases an opposite influence on the responses. Desirability function was used to attain simultaneous optimization of both responses. The desired goals were achieved for both systemic and local use of celecoxib. Experimental values obtained from the optimized formulations were in both cases very close to the predicted values, thus confirming the validity of the generated mathematical model. These results demonstrated the effectiveness of the proposed jointed use of drug cyclodextrin complexation and chitosan-Ca-alginate microsphere vectorization, as well as the usefulness of the multivariate approach for the preparation of colon-targeted celecoxib microspheres with optimized properties.

  16. PVP-coated, negatively charged silver nanoparticles: A multi-center study of their physicochemical characteristics, cell culture and in vivo experiments

    Directory of Open Access Journals (Sweden)

    Sebastian Ahlberg

    2014-11-01

    Full Text Available PVP-capped silver nanoparticles with a diameter of the metallic core of 70 nm, a hydrodynamic diameter of 120 nm and a zeta potential of −20 mV were prepared and investigated with regard to their biological activity. This review summarizes the physicochemical properties (dissolution, protein adsorption, dispersability of these nanoparticles and the cellular consequences of the exposure of a broad range of biological test systems to this defined type of silver nanoparticles. Silver nanoparticles dissolve in water in the presence of oxygen. In addition, in biological media (i.e., in the presence of proteins the surface of silver nanoparticles is rapidly coated by a protein corona that influences their physicochemical and biological properties including cellular uptake. Silver nanoparticles are taken up by cell-type specific endocytosis pathways as demonstrated for hMSC, primary T-cells, primary monocytes, and astrocytes. A visualization of particles inside cells is possible by X-ray microscopy, fluorescence microscopy, and combined FIB/SEM analysis. By staining organelles, their localization inside the cell can be additionally determined. While primary brain astrocytes are shown to be fairly tolerant toward silver nanoparticles, silver nanoparticles induce the formation of DNA double-strand-breaks (DSB and lead to chromosomal aberrations and sister-chromatid exchanges in Chinese hamster fibroblast cell lines (CHO9, K1, V79B. An exposure of rats to silver nanoparticles in vivo induced a moderate pulmonary toxicity, however, only at rather high concentrations. The same was found in precision-cut lung slices of rats in which silver nanoparticles remained mainly at the tissue surface. In a human 3D triple-cell culture model consisting of three cell types (alveolar epithelial cells, macrophages, and dendritic cells, adverse effects were also only found at high silver concentrations. The silver ions that are released from silver nanoparticles may be

  17. Improvement in Dissolution Properties of piroxicam by Complexation with β- Cyclodextrin and PVP%固体分散技术与包合技术对吡罗昔康溶出度的影响

    Institute of Scientific and Technical Information of China (English)

    胡鹏翼; 易以木

    2007-01-01

    目的 考察固体分散技术及包合技术对吡罗昔康溶出度的影响.方法 以聚乙烯吡咯烷酮(PVP)为载体制备固体分散体;以β-环糊精(β-CD) 包合技术制备包合物.以差示扫描量热法(DSC)鉴定吡罗昔康在体系中的存在形态;以水为溶出介质, 紫外分光光度法测定不同制备工艺下成品的体外溶出度.结果 差热分析图谱表明,吡罗昔康β-CD包合物以及吡罗昔康-PVP(1:6,1:8)的固体分散体中药物以非晶型存在,而吡罗昔康-PVP(1:2,1:4)的固体分散体中,药物与载体形成低共熔物,药物以微晶形式存在于载体中;体外溶出结果 表明环糊精包合物和载药比为1:6,1:8的固体分散体的溶出速率与相应物理混合物及原料药间差异有极显著性(P<0.01).结论 制成固体分散体和β-环糊精包合物均能显著提高吡罗昔康的溶出速率.

  18. Effect of hydroxypropyl cellulose (HPC), polyvinylpyrrolidone (PVP) and polyethylene glycol (PEG) on Nd-TiO2/graphene oxide nanocomposite for removal of lead(II) and copper(II) from aquatic media.

    Science.gov (United States)

    Samadi, Susan; Mirseyfifard, Sayed Mohammad Hosain; Assari, Mina; Hassannejad, Marzieh

    2017-07-01

    In order to investigate the effect of hydroxypropyl cellulose (HPC), polyvinylpyrrolidone (PVP) and polyethylene glycol (PEG) on adsorbing capacity of nanosorbent Nd-TiO2/GO, Nd-TiO2/HPC/GO, Nd-TiO2/PVP/GO and Nd-TiO2/PEG/GO nanocomposites were synthesized. Studies by Fourier transform infrared spectroscopy confirmed the expected structure and X-ray diffraction results confirmed the formation of crystalline phase of anatase titania and also graphene oxide (GO). Scanning electron microscopy pictures and energy dispersive X-ray spectroscopy analysis showed the formation of Nd-TiO2 nanoparticles. These nanocomposites were used for removal of lead(II) and copper(II) from water and the effective factors on removal were optimized. The results showed that the maximum removal for all three nanocomposites was at pH = 7. The amount of adsorbent and contact time for Nd-TiO2/HPC/GO and Nd-TiO2/PVP/GO nanocomposites was equal to 0.02 g and 20 minutes respectively, but they were equal to 0.01 g and 15 minutes for Nd-TiO2/PEG/GO nanocomposite. Investigating the effect of interfering ions showed they had no considerable effect on removal efficiency. In order to investigate the effect of photocatalytic activity in optimal conditions and in the presence of visible-ultraviolet light, the removal process was performed. The results showed an increase in removal efficiency. Furthermore, the ability of synthesized nanosorbents to decompose organic compounds available in water was confirmed and their energy band gaps were calculated.

  19. An efficient Trojan delivery of tetrandrine by poly(N-vinylpyrrolidone-block-poly(ε-caprolactone (PVP-b-PCL nanoparticles shows enhanced apoptotic induction of lung cancer cells and inhibition of its migration and invasion

    Directory of Open Access Journals (Sweden)

    Xu H

    2013-12-01

    Full Text Available Huae Xu,1,2 Zhibo Hou,3 Hao Zhang,4 Hui Kong,2 Xiaolin Li,4 Hong Wang,2 Weiping Xie21Department of Pharmacy, 2Department of Respiratory Medicine, The First Affiliated Hospital of Nanjing Medical University, Nanjing, People's Republic of China; 3First Department of Respiratory Medicine, Nanjing Chest Hospital, Nanjing, People's Republic of China; 4Department of Geriatric Gastroenterology, The First Affiliated Hospital of Nanjing Medical University, Nanjing, People's Republic of ChinaAbstract: Earlier studies have demonstrated the promising antitumor effect of tetrandrine (Tet against a series of cancers. However, the poor solubility of Tet limits its application, while its hydrophobicity makes Tet a potential model drug for nanodelivery systems. We report on a simple way of preparing drug-loaded nanoparticles formed by amphiphilic poly(N-vinylpyrrolidone-block-poly(ε-caprolactone (PVP-b-PCL copolymers with Tet as a model drug. The mean diameters of Tet-loaded PVP-b-PCL nanoparticles (Tet-NPs were between 110 nm and 125 nm with a negative zeta potential slightly below 0 mV. Tet was incorporated into PVP-b-PCL nanoparticles with high loading efficiency. Different feeding ratios showed different influences on sizes, zeta potentials, and the drug loading efficiencies of Tet-NPs. An in vitro release study shows the sustained release pattern of Tet-NPs. It is shown that the uptake of Tet-NPs is mainly mediated by the endocytosis of nanoparticles, which is more efficient than the filtration of free Tet. Further experiments including fluorescence activated cell sorting and Western blotting indicated that this Trojan strategy of delivering Tet in PVP-b-PCL nanoparticles via endocytosis leads to enhanced induction of apoptosis in the non-small cell lung cancer cell A549 line; enhanced apoptosis is achieved by inhibiting the expression of anti-apoptotic Bcl-2 and Bcl-xL proteins. Moreover, Tet-NPs more efficiently inhibit the ability of cell migration and

  20. 静电纺丝法制备金纳米粒子/PVP复合纳米纤维%The Preparation of Gold Nanoparticles/PVP Composites Nanofibers by Electrospinning Technique

    Institute of Scientific and Technical Information of China (English)

    白杰

    2011-01-01

    The paper dealing with the preparation of gold nanoparticles by chemical reducing from relativety with a solution of HAuCl4 with N2H4· H2O as reduction reagent and polyvinylpyrrolidone (PVP) as dispersion and stabilizer,the smaller gold nanoparticles were obtained, the optical property of gold nanoparticles in PVP aqueous solution was observed by UV-visible absorption spectra. Gold nanoparticles/PVP composite fibers were prepared by electrospinning technique. The composite nanofibers were characterized by scanning electron microscope (SEM) and X-ray diffraction (XRD). Field-emission scanning electron microscopy (FESEM) showed the morphology of fibers,and the diameters of composite nanofibers obviously decreased with the increasing concentration of gold nanoparticles in the solution. The existence of the gold nanoparticles was approved by XRD patterns.%采用水合肼还原一定浓度氯金酸溶液的方法,在聚乙烯吡咯烷酮(PVP)作保护剂的乙醇/水溶液中,成功制备出粒度较小,且高度分散的金溶胶,紫外吸收光谱证实了溶液中金纳米粒子的存在.采用静电纺丝技术制备了AuNs/PVP复合纳米纤维.采用扫描电镜(SEM)和X射线衍射(XRD)等分析手段对纤维的表面形貌等进行了表征.由扫描电镜照片可以看出所制得的纤维的尺寸较为均匀,随着纺前溶液内金纳米粒子含量的增加,获得的复合纤维的直径随之减小;XRD测试显示出样品内含有立方面心结构的金纳米粒子.

  1. Proposed phase 2/ step 2 in-vitro test on basis of EN 14561 for standardised testing of the wound antiseptics PVP-iodine, chlorhexidine digluconate, polihexanide and octenidine dihydrochloride.

    Science.gov (United States)

    Schedler, Kathrin; Assadian, Ojan; Brautferger, Uta; Müller, Gerald; Koburger, Torsten; Classen, Simon; Kramer, Axel

    2017-02-13

    Currently, there is no agreed standard for exploring the antimicrobial activity of wound antiseptics in a phase 2/ step 2 test protocol. In the present study, a standardised in-vitro test is proposed, which allows to test potential antiseptics in a more realistically simulation of conditions found in wounds as in a suspension test. Furthermore, factors potentially influencing test results such as type of materials used as test carrier or various compositions of organic soil challenge were investigated in detail. This proposed phase 2/ step 2 test method was modified on basis of the EN 14561 by drying the microbial test suspension on a metal carrier for 1 h, overlaying the test wound antiseptic, washing-off, neutralization, and dispersion at serial dilutions at the end of the required exposure time yielded reproducible, consistent test results. The difference between the rapid onset of the antiseptic effect of PVP-I and the delayed onset especially of polihexanide was apparent. Among surface-active antimicrobial compounds, octenidine was more effective than chlorhexidine digluconate and polihexanide, with some differences depending on the test organisms. However, octenidine and PVP-I were approximately equivalent in efficiency and microbial spectrum, while polihexanide required longer exposure times or higher concentrations for a comparable antimicrobial efficacy. Overall, this method allowed testing and comparing differ liquid and gel based antimicrobial compounds in a standardised setting.

  2. k-型卡拉胶/聚乙烯吡咯烷酮共混水凝胶的辐射制备及性质研究%燬tudies on Radiation Preparation and Characteristics of k-Carrageenan/PVP Blend Hydrogel

    Institute of Scientific and Technical Information of China (English)

    翟茂林; 哈鸿飞; 吉井文男; 幕内惠三

    2001-01-01

    In this work,a series of hydrogels in the form of rod were prepared from κ-carrageenan(KC) and poly(N-vinyl pyrrolidone) (PVP) by gamma radiation with 60Co γ source at room temperature.The properties of the prepared hydrogels,such as the gel strength,gel fraction and swelling behavior were investigated.High molecular weight PVP (k-90) blending with KC could produces excellent hydrogels,but low molecular weight PVP (k-30) dosen't.With increasing KC content in the prepared hydrogel,both the gel strength and the equilibrium degree of swelling were improved.The experimental analyses showed that the crosslinking reaction of PVP(k-90) was quicker than the degradation of KC at low dose(less than 30 kGy),and the degradation of KC was inhibited in PVP/KC mixture system.An interpenetrating polymer network (IPN) hydrogel composed of PVP (a chemically crosslinked network) and KC (a physically crosslinked network) was proposed.In addition,the dose influenced greatly the preparation of the hydrogel.%采用辐射技术制备了κ-型卡拉胶(KC)/聚乙烯基吡咯烷酮(PVP)共混水凝胶,研究了共混凝胶内KC含量、PVP的分子量和辐照剂量等对KC/PVP共混水凝胶性质的影响.实验发现,KC与高分子量的PVP(k-90)共混后在一定剂量范围内辐照可得到高强度、高溶胀行为的KC/PVP共混水凝胶,随着共混凝胶内KC含量的增加,凝胶强度及溶胀性能均显著提高.分析表明,KC与高分子量的PVP共混后,在较低剂量下KC的降解被抑制,从而获得一种由物理交联的KC和化学交联的PVP形成的互穿网络(IPN)凝胶.

  3. 包膜型PVPK30屈螺酮固体分散体阴道环相关研究%Study on capsulated drospirenone treated by PVP solid dispersion IVR

    Institute of Scientific and Technical Information of China (English)

    张莹; 李春晓; 段雪艳; 刘颖; 宁美英

    2013-01-01

    OBJECTIVE To study the compatibility of intravaginal ring (IVR) containing drospirenone by HPLC gradient method. METHODS Capsulated drospirenone IVR and capsulated drospirenone which was treated by PVP solid dispersion IVR were obtained by using hot vulcanization method with silicone elastomer as the matrix polymer. In vitro drug release testing was conducted in a dissolution apparatus, and release samples were determined by the UV-vis spectrophotometry. The stabilities of drospirenone and PVP, silicone rubber were inspected by HPLC gradient method under the condition of 60 ℃ , relative humidity of 75% and illuminated at 4 500 Lx respectively for 5 d and 10 d. RESULTS Compared with capsulated vaginal ring device, the daily release quantity of capsulated drospirenone-PVP IVR in vitro increased and sustained 21 days at the release rate of 1. 0 mg·d-1. Under strong light, high temperature, high humidity conditions, drospirenone raw materials and formulation excipients PVPK30 and silicon rubber had no significant interactions, and indicated good compatibility. CONCLUSION PVP could improve the drospirenone release from the intravaginal ring and the formulation was stable, so as to provide a scientific basis for adjustment and optimization of prescription.%目的:采用HPLC梯度法考察屈螺酮控释阴道环中原辅料的相容性.方法:以医用硅橡胶弹性体为药物载体,采用热压硫化法制备包膜型屈螺酮阴道环及包膜型PVPK30屈螺酮固体分散体阴道环,紫外分光光度法测定2种阴道环的体外释放情况.HPLC梯度法考察屈螺酮原料药与辅料PVPK30和硅橡胶混合物在经光照、高温及高湿条件处理后的稳定性.结果:包膜型PVP固体分散体屈螺酮阴道环较包膜型屈螺酮阴道环体外释放度有明显提高,每日释放药物约为1.0mg,持续平稳释放时间可达21 d.光照、高温、高湿条件下,屈螺酮原料药与拟定辅料PVPK30和硅橡胶无明显相互作

  4. 活性炭吸附及喷雾干燥处理对聚乙烯吡咯烷酮K-30产品品质的影响%The Effect of the Activated Carbon Adsorption and Spray-drying Treatment for the PVP K-30 Quality

    Institute of Scientific and Technical Information of China (English)

    陈德义; 王明洪; 周志明; 蒲朝君

    2011-01-01

    用液相色谱法研究了不同材质活性炭对聚乙烯吡咯烷酮(PVP)K-30浆料中有机杂质的吸附能力,探讨了喷雾干燥过程对产品品质的影响,并对聚乙烯吡咯烷酮(PVP)K-30产品中的有色杂质进行了初步的推断和分析,最终通过简单的前处理在实验室阶段生产出了比BASF产品色度更低、残单更少的聚乙烯吡咯烷酮(PVP)K-30产品。%In this paper, the adsorption capacity of different activated carbon for organic impurities in PVP K-30 slurry was studied by liquid chromatography method, then discussed the effect of spray-drying treat- ment for the PVP K-30 Quality, and preliminary infered and analyzed the colored impurities in PVP K-30 products, finally got the PVP K-30 with less color and residual content than BASF's product by processing a simple pre-treatment.

  5. Novel electrochemical biosensor based on PVP capped CoFe2O4@CdSe core-shell nanoparticles modified electrode for ultra-trace level determination of rifampicin by square wave adsorptive stripping voltammetry.

    Science.gov (United States)

    Asadpour-Zeynali, Karim; Mollarasouli, Fariba

    2017-06-15

    This work introduces a new electrochemical sensor based on polyvinyl pyrrolidone capped CoFe2O4@CdSe core-shell modified electrode for a rapid detection and highly sensitive determination of rifampicin (RIF) by square wave adsorptive stripping voltammetry. The new PVP capped CoFe2O4@CdSe with core-shell nanostructure was synthesized by a facile synthesis method for the first time. PVP can act as a capping and etching agent for protection of the outer surface nanoparticles and formation of a mesoporous shell, respectively. Another important feature of this work is the choice of the ligand (1,10-phenanthroline) for precursor cadmium complex that works as a chelating agent in order to increase optical and electrical properties and stability of prepared nanomaterial. The nanoparticles have been characterized by field emission scanning electron microscopy (FESEM), transmission electron microscope (TEM), energy dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), UV-vis, photoluminescence (PL) spectroscopy, FT-IR, and cyclic voltammetry techniques. The PL spectroscopy study of CoFe2O4@CdSe has shown significant PL quenching by the formation of CoFe2O4 core inside CdSe, this shows that CoFe2O4 NPs are efficient electron acceptors with the CdSe. It is clearly observed that the biosensor can significantly enhance electrocatalytic activity towards the oxidation of RIF, under the optimal conditions. The novelty of this work arises from the new synthesis method for the core-shell of CoFe2O4@CdSe. Then, the novel electrochemical biosensor was fabricated for ultra-trace level determination of rifampicin with very low detection limit (4.55×10(-17)M) and a wide linear range from 1.0×10(-16) to 1.0×10(-7)M. The fabricated biosensor showed high sensitivity and selectivity, good reproducibility and stability. Therefore, it was successfully applied for the determination of ultra-trace RIF amounts in biological and pharmaceutical samples with satisfactory recovery data.

  6. Preparation and property of superfine PAN/PVP composite nanofibers%超细PAN/PVP复合纳米纤维的制备及其性能研究

    Institute of Scientific and Technical Information of China (English)

    韩瑞; 梅林玉; 付一政; 刘亚青

    2015-01-01

    采用五因素五水平正交实验研究了溶液浓度、PAN/PVP比例、电压、接收距离和LiCl含量对聚丙烯腈(PAN)/聚乙烯吡咯烷酮(PVP)复合纳米纤维形貌的影响,成功的制备出了直径在100nm以下形貌优良的PAN/PVP复合纳米纤维,并通过XRD进行表征;并对PAN/PVP复合纤维在400℃下进行了低温碳化处理,采用四探针电导仪对纤维的电导率进行了研究.结果表明:制备PAN/PVP复合纤维最优参数组合为:浓度10 wt%、PAN/PVP为5/5、电压10kV、接收距离20cm、LiCl含量0.5 wt%;随溶液浓度增大,PAN/PVP复合纤维的结晶性能增大;PAN/PVP比例为5/5时,纤维的电导率最高,能达到1.2×10-2S/m.

  7. Suicide attempt with a mix of synthetic cannabinoids and synthetic cathinones: Case report of non-fatal intoxication with AB-CHMINACA, AB-FUBINACA, alpha-PHP, alpha-PVP and 4-CMC.

    Science.gov (United States)

    Klavž, Janez; Gorenjak, Maksimiljan; Marinšek, Martin

    2016-08-01

    We report on a case of intoxication with a mix of new psychoactive substances. A 38-year-old male was brought to the emergency department (ED) following the ingestion of an unknown drug in a suicide attempt. During the transport, he became progressively more somnolent and unresponsive to painful stimuli. Urine and stomach content were collected on admission to be screened for drugs of abuse and medicinal drugs. After admission, the patient's next of kin presented five small grip seal plastic bags containing different powders/crystals, and they were sent for analysis along with urine and stomach content to the toxicology laboratory. An easy and rapid sample preparation technique was applied for the extraction of urine and stomach content. Samples were extracted with liquid-liquid extraction (LLE) technique and analysed using gas chromatography-mass spectrometry (GC-MS). A small amount of powder material from the bags was diluted in methanol and injected directly into the GC-MS instrument. Obtained spectra (EI) were evaluated against SWGDRUG library. Five different designer drugs were identified in the powder material, including synthetic cannabinoids (AB-CHMINACA, AB-FUBINACA) and synthetic cathinones (alpha-PHP, alpha-PVP and 4-CMC). With the exception of 4-CMC, all of these substances were also detected in the stomach content along with the prescription drugs. This is the first time that a positive identification of these five drugs has been made by a clinical laboratory in Slovenia.

  8. 溶剂挥发法制备聚合物电解质P(VDF-HFP)/PVP及其性能%Preparation and characterization of polymer electrolyte P (VDF-HFP)/PVP by solvent evaporation method

    Institute of Scientific and Technical Information of China (English)

    袁艳; 陈白珍; 陈亚

    2013-01-01

    A kind of microporous membrane based on the blend of PVP and P (VDF-HFP) was prepared by solvent evaporation method, and the LiCoO 2/Li polymer batteries were assembled with the microporous membrane which absorbed electrolyte. The polymer membrane and electrolyte were characterized by scanning electronic morphology (SEM), differential scanning calorimeter-thermo gravimetry (DSC-TG), electrochemical impedance spectroscopy (EIS) and linear scanning voltammetry (LSV). The electrochemical performance of LiCoO2/Li polymer battery was tested by charge-discharge test with constant current. The results show that this polymer membrane has abundant micro pores and exhibits up to 480%uptake of liquid electrolyte. The ionic conductivity of the polymer electrolyte is 4.79×10-3 S/cm at room temperature and its electrochemical stable window is 5.5 V. The LiCoO2/Li battery based on the polymer electrolyte displays an initial discharge capacity of 142.37 mA∙h/g and discharge plateau of about 3.86 V at 0.1C. After 30 cycles, its discharge capacity remains 136.68 mA∙h/g, and coulombic efficiency stays around 97%.%以聚乙烯基吡咯烷酮(PVP)与聚偏氟乙烯-六氟丙烯[P(VDF-HFP)]的共混物为基质,通过溶剂挥发法制备聚合物微孔膜,将其浸取电解液后制成聚合物电解质并组装LiCoO 2/Li聚合物锂离子电池。采用扫描电子显微镜、差热-热重分析、交流阻抗、线性伏安扫描等技术对制备的聚合物微孔膜及电解质进行表征,采用恒流充放电方法对组装的聚合物锂离子电池进行电化学性能测试。结果表明:溶剂挥发法制得的聚合物膜孔穴丰富,液态电解质吸液率可达到480%;浸取电解液后获得的聚合物电解质室温离子电导率为4.79×10-3 S/cm,电化学稳定窗口为5.5 V;基于该聚合物电解质装配的LiCoO 2/Li电池在0.1C倍率充放电时,首次放电容量为142.37 mA∙h/g,放电平台约为3.86 V,30

  9. Effects of PVP dispersant on electrochemical performance of high rate Li-ion cells with LiFePO4 cathode%PVP分散剂对高倍率LiFePO4锂离子蓄电池性能作用

    Institute of Scientific and Technical Information of China (English)

    刘文刚; 高俊奎; 刘兴江

    2015-01-01

    The particle size analysis, rheological analysis and SEM observation were applied to study the effects of PVP dispersant content on particle size distribution and rheologic behavior of LiFePO4 slurry. 18650 Li-ion cells with LiFePO4 cathode were fabricated through formula optimization, and cycle and rate performances of the cells were evaluated and compared to the cellwithout PVP. The results show that the slurry viscosity decreases with the increase of PVP content, and the particle size of slurry declines firstly then rises. The best PVP amount is 0.4%~0.8%. The LiFePO4 cathode with 0.6%PVP was used to prepare 1.1 Ah 18650 Li-ion cells, having perfect high rate discharge and cycle performances. More than 90%of capacity retention after charging at 1.5 A and discharging at 10 A is achieved after 900 cycles for the cellwith PVP, which is superior to traditional one. The capacity retention is 94.6%even at 30 A discharge rate for the cellwith PVP.%采用粒度分析、流变分析、扫描电子显微镜法(SEM)等技术研究了PVP分散剂添加量对LiFePO4正极浆料粒度分布及流变性的影响规律。通过配方优化,制作高倍率放电18650型LiFePO4锂离子电池,并对其循环及倍率等性能进行了对比研究。结果表明,随着PVP加入量的提高,浆料的黏度呈现下降的趋势,浆料的粒度则先减小后增大,PVP加入量在0.4%~0.8%时,可达到最优的浆料分散效果。用PVP含量0.6%的LiFePO4正极浆料制作容量为1.1 Ah的18650电池表现出优异的高倍率放电及循环性能,在1.5 A充10 A放的条件下,900次循环后容量保持率高达90%以上,优于未使用PVP分散剂的传统磷酸铁锂电池;30 A高倍率放电容量可达到标称容量的94.6%。

  10. Continuous Mullite Fibres Prepared by Sol-Gel Dry Spinning Method Using PVP as Spinning Aid%PVP为纺丝助剂溶胶-凝胶干法纺丝制备连续莫来石纤维

    Institute of Scientific and Technical Information of China (English)

    金明明; 康庄; 刘朋超; 马敬红; 顾利霞; 徐坚

    2011-01-01

    采用硝酸铝(AN)和异丙醇铝(AIP)作为铝源,正硅酸乙酯(TEOS)为硅源,添加10%聚乙烯吡咯烷酮(PVP)为纺丝助剂,合成了莫来石溶胶,在溶胶-凝胶转变过程中控制溶胶固含量在35%左右,通过干法纺丝可得到连续莫来石凝胶纤维,经过1300℃高温烧结后得到直径16μm莫来石陶瓷纤维。通过高温DSC-TG和XRD测试发现,烧结温度为700℃时开始形成亚稳态莫来石,烧结温度为1300℃时形成了最终态莫来石。通过扫描电镜(FE-SEM)对初生纤维和陶瓷纤维进行测试,制得的莫来石陶瓷纤维表面光滑,缺陷少,结构较致密。%The mullite sol was prepared by sol-gel method from an aqueous solution of aluminum nitrate(AN),aluminum isopropoxide(AIP) and tetraethylorthosilicate(TEOS).PVP was used as the spinning aid.Continuous mullite ceramic fibres were fabricated by dry spinning technology and sintered at 1300 ℃.The mullite sol can be continuous spinning by determining better solid content at about 35% in the concentration process.The green fibers and sintered fibres were observed and analyzed by DSC-TG,XRD and SEM.The results show that the sintered fibres have smooth surface and few defects,the diameter of sintered fibers is 10 μm~20 μm,only mullite crystals are formed after sintering at 1300 ℃.

  11. PVP联合PKP结合药物治疗多节段骨质疏松性椎体压缩性骨折%Effect of PKP and PVP combined with drug therapy on the treatment of multi-segmental steoporotic vertebral compression fractures

    Institute of Scientific and Technical Information of China (English)

    熊斌; 赵敏; 周江军; 付美清; 史柏娜; 高伟; 杨俊

    2013-01-01

    目的 探讨椎体成形术(PVP)联合经皮椎体后凸成形术(PKP)治疗多节段老年骨质疏松性椎体压缩性骨折(OVCF)的疗效.方法 30例(108椎)OVCF患者行PVP+PKP术,术后给予鲑鱼降钙素、活性维生素D和钙剂治疗(治疗组).20例(62椎)患者给予卧床休息3月,鲑鱼降钙素、活性维生素D和钙剂治疗(对照组).两组患者分别于0 w、24 w和48 w测股骨颈和胸腰椎骨密度.应用视觉模拟疼痛评分(VAS)对患者疼痛进行评价.结果术后0 w、24 w和48 w,两组患者股骨颈和胸腰椎多节段胸腰椎骨密度值,差异无统计学意义.术前、术后0 w、24 w和48 w治疗组患者VAS评分明显降低,较对照组患者VAS评分具有统计学意义(P<0.05).结论 应用PVP联合PKP治疗多节段(OVCF)能有效缓解疼痛,是一种简单、安全有效的方法.%Objective To explore the clinical effect of PVP and PKP on the treatment of multi -segmental osteoporotic vertebral compression fractures ( OVCF) in elderly patients. Methods In treatment group, 30 OVCF patients ( 108 vertebrae) were treated by PVP and PKP. Salmon calcitonin, active vitamin D, and calcium were given after the operation. In control group, 20 patients (62 vertebrae) were treated with the same drugs without operation, resting in bed for 3 months instead. Bone mineral density of the femoral neck and the lumbar vertebrae was measured at the 0th, 24th, and 48th week, respectively. VAS was used to evaluate the pain of the patients. Results At the 0th, 24th, and 48th week after operation, bone mineral density of the femoral neck and the lumbar vertebrae between both groups had no statistical significance. But the VAS score decreased obviously in treatment group compared with that in the control group ( P < 0. 05). Conclusion PVP and PKP can reduce the pain of patients with multi -segmental OVCF, which is simple, safe, and efficient.

  12. PVP治疗骨质疏松性椎体压缩性骨折对患椎邻近椎体退变和骨折发生率的影响%Adjacent segment degeneration and again fracture incidence of influence after PVP treat traumatic compressibility vertebral fracture

    Institute of Scientific and Technical Information of China (English)

    隋杰; 李志忠; 林永新; 孙国栋; 焦根龙; 任炼

    2011-01-01

    目的 分析经皮椎体成形术(PVP)治疗骨质疏松性椎体压缩性骨折对患椎邻近椎体退变及骨折发生率的影响.方法 骨质疏9松性椎体压缩骨折患者51例,随机分为手术组30例和对照组21例,分别采用PVP治疗和保守治疗.通过X线片测算两组治疗前及治疗后1 a患椎上下椎体前缘压缩率、中柱压缩率、后倾角(θ角).观察治疗后1 a两组患椎邻近椎体的退变情况及骨折发生率.结果 手术组术后1 a患椎上下椎体前缘压缩率、中柱压缩率及θ角均较对照组增大(P均<0.01).手术组术后1 a发生患椎邻近椎体骨折5例(16.7%),对照组无邻近椎体骨折发生(P<0.05).结论 PVP治疗骨质疏松椎体压缩性骨折可加速患椎邻近椎体退变,并增加邻近椎体骨折的风险.%Objective To analysis adjacent segment degeneration and again fracture incidence of influence that percutaneous vertebroplasty(PVP) treat traumatic compressibility vertebral fracture postoperative.Methods 51 patients diagnosed with osteoporotic vertebral compression fractures ,30 cases were treated with PVP as surgical treatment group, and 21 cases for the conservative group.All patients examined with the standards X-ray,then observed variation of adjacent vertebral body height and wedge angle,compared with these results after 1 a.The adjacent segment degeneration and the risk of fracture again with 1 a after operation in two groups were recorded.Results There were difference in adjacent vertebral body height and wedge angle between two groups in 1 a after operation ( P <0.05) ,incidence of fracture in surgical treatment group was 16.7%.The control group was without adjacent vertebral fractures occurred.Conclusion PVP for the treatment of traumatic compressibility vertebral fracrure can accelerate with adjacent segment degeneration, and increase the risk of fracture of adjacent segment.

  13. Estabelecimento e multiplicação in vitro de brotos no processo de micropropagação de cultivares de bananeira (Musa spp. Establishment and in vitro multiplication of banana (Musa spp. cultivars with the use of PVP (Polyvinylpyrrolidone

    Directory of Open Access Journals (Sweden)

    Hérica Santos de Oliveira

    2011-01-01

    Full Text Available A banana (Musa spp. é uma das frutas mais consumidas no mundo, e amplamente cultivada no Brasil, porém doenças como as sigatokas, negra e amarela, vêm reduzindo a sua produção. A disponibilização imediata de novas cultivares resistentes às principais doenças é limitada pela propagação convencional. A micropropagação é uma alternativa para a produção de mudas com qualidade fitossanitária e vegetativa, mas apresenta fatores que dificultam sua aplicação como a contaminação por fungos e bactérias, associada à oxidação dos explantes. O objetivo desse trabalho foi adaptar e/ou otimizar as etapas do processo de micropropagação para diferentes cultivares de bananeira, por meio do controle de oxidação, contaminação, e multiplicação de brotos, sendo utilizadas as cultivares Caipira (AAA, BRS Caprichosa (AAAB, Pacovan Ken (AAAB, Preciosa (AAAB, PV 03-76 (AAAB, Thap Maeo (AAB. No estudo foram utilizados o antibiótico sulfato de estreptomicina e o fungicida Opera® (BASF visando reduzir a contaminação in vitro provocada por bactérias e fungos, além do anti-oxidante PVP (polivinilpirrolidona para controlar a oxidação. Houve redução da contaminação com uso do sulfato de estreptomicina à concentração de 100 mg L-1 e da oxidação com PVP a 4 g L-1. Na fase de multiplicação de brotos, as cultivares apresentaram médias que variaram de 1,90 a 4,75 brotos/explante. A cultivar caipira (AAA destacou-se das demais com a maior taxa de multiplicação de brotos após três subcultivos, média de 41,50 brotos por rizoma.The banana (Musa spp is one of the most consumed fruits in the world and is widely consumed in Brazil, but diseases such as yellow and black sigatoka have been reducing its production. The immediate availability of new cultivars resistant to major diseases is limited by conventional propagation. The micropropagation, is an alternative for the production of seedlings with phytosanitarium and vegetative

  14. Au@PVP核壳纳米粒子作为表面增强拉曼散射基底检测孔雀石绿%Au@PVP Core-Shell Nanoparticles Used as Surface-Enhanced Raman Spectroscopic Substrate to Detect Malachite Green

    Institute of Scientific and Technical Information of China (English)

    徐宁宁; 张芹; 郭伟; 李钦涛; 徐杰

    2016-01-01

    The core-shell nanopaticles of Au@polyvinyl-pyrrolidone ( PVP) with uniform size and controllabe shell-thickness were prepared by hydrothermal method. The core-shell nanoparticles could be assembled to be the monolayer array on Si substrate relying on the dispersion of core-shell nanoparticles arising from PVP shell. The malachite green ( MG ) absorbed by H-bond could be detected on the array under the electromagnetic enhancement of inner-core Au nanoparticles. Under the conditions of the optimum shell-thickness of Au@PVP and the appropriate absorbed time of MG, the detection of MG could be realized in the linear range from 1 × 10-10 mol/L to 1 × 10-5 mol/L with the correlation coefficient ( R2 ) of 0. 98. The detection limit was 10-12 mol/L. This method was applied to the determination of MG in tilapia fish fillets of Xiagang market. No MG was found in this real sample. The spiked recoveries of the sample ranged from 70. 8% to 126. 0%. This method is simple and accurate, and can be used for detection of MG in the fish.%采用水热法合成了粒径均一、壳层厚度可控的Au@PVP核壳纳米粒子,利用壳层PVP分子分散纳米粒子的特性,使其形成均一、排列致密的单层结构,利用其内核金纳米粒子的等离子共振效应实现了孔雀石绿( MG)分子的表面增强拉曼检测。通过优化吸附时间与壳层厚度,在致密的、均匀的核壳纳米粒子表面增强拉曼散射(SERS)基底上实现MG分子高灵敏分析检测,检测线性范围1×10-10~1×10-5 mol/L,线性相关系数R2达到0.98,检出限可达1×10-12 mol/L。将本方法用于罗非鱼鱼肉中MG含量检测,样品未检出,样品加标回收率为70.8%~126.0%。结果表明,本方法快速准确、操作简单,可用于鱼肉中MG的快速检测。

  15. 系统评价指导下PVP/PKP治疗骨质疏松性胸腰椎压缩性骨折的临床疗效分析%Therapeutic effect of percutaneous vertebroplasty and kyphoplasty on treatment of osteoporotic vertebral compression fracture

    Institute of Scientific and Technical Information of China (English)

    孟纯阳; 李庆伟; 胡侦明; 郝杰; 盛遵启

    2011-01-01

    Objective To observe the clinical efficacy of percutaneous vertebroplasty (PVP) with percutaneous kyphoplasty (PKP) in the treatment of osteoporotic vertebral compression fracture(OVCF) by systematic review. Methods From September 2005 to March 2009,46 cases of fresh OVCF were treated. Patients were divided into 2 groups (A, B), according to Jikei grade, Genant semiquantitative method, injury vertebra number. Twenty-five cases(group A)were treated by PVP,8 males and 17 females with the age of 52 - 78 years (average 69). Vertebra segment of fracture was within T6 - L5 (14 in case thoracical vertebrae and 11 lumbar vertebrae). Twenty-one cases(group B)were treated by PKP,There were 6 males and 15 females with the age of 54 - 82 years (average 71). Vertebra segment of fracture was within T6 - L4 (12 in case thoracical vertebrae and 9 lumbar vertebrae). The clinical efficacy, incidence rate of complication, the anterior height of vertebrae body,visual analogue pain scale(VAS) ,ease of pain were measured preoperatively and at 6 weeks, 3 and 6 months and 1 year postoperatively between the two groups. Results All the patients were followed up for 12 -45 months with an average of 23.5 months. The average recovery of anterior height of vertebrae body was respectively(85.95 ± 4.31) % in group A and (93.64 ± 3.35) % in group B,which statistically difference in vertebral height between two groups (P < 0.05). No statistical significant difference was seen in VAS, analgesic durg (AID) and ease of pain complication between two groups (P >0. 05). Statistical significant difference was noted in pre-postoperatively between intra-two groups (P <0. 05). Conclusions PVP and PKP can quickly relieve pain and enhance vertebral stability in treating thoracolumbar OVCF according to evaluation parameter, and have the similar therapeutic efficacy in treatment of OVCF with minimal invasion. However, PKP is superior in the recovery of vertebral height.%目的 探讨系统评价指导

  16. 椎基静脉孔及椎体静脉解剖在椎体成形术中的意义%Anatomic distribution of basivertebral foramen and vertebral vein in vertebral bodies of T8~L5 and its clinical significance in PVP and PKP

    Institute of Scientific and Technical Information of China (English)

    王素春; 施建东; 陆爱清; 王志荣; 张烽

    2015-01-01

    Objective To provide anatomic data for less complications of bone cement leakage in PKP and PVP. Methods A total of 40 health adults underwent multi-slice CT thin slice scans and three-dimensional reconstruction. In the horizontal and sagittal CT reconstruction images, display frequency of basivertebral foramen (BF) and vertebral vein (VV)of the branches of basivertebral venous system in vertebral bodies of T8~L5 were calculated. The sagittal diameter of vertebral body (VD), BF weight (BFW), BF depth (BFD), BF high (BFH) were measured. The distance between the BF and each side inthe horizontal and sagittal CT images were also measured. The measured parameters were analyzed statistically. Result Display frequency of BF and VV was gradually increasing from T8 to L5. Display frequencies of BF and VV in vertebral bodies were no significantly different between male and female (P>0.05). The distance from the BF to left or right side in the horizontal CT images were not significantly different (P>0.05). The distance from the BF to the cranial or caudal endplate in the saggital CT images were significantly different (P<0.05). The distance from the BF to the cranial endplate was shorter than to the caudal endplate. Conclusion For clinic operators, the knowledge of anatomic distribution of BF and VV in vertebral bodies helps to reduce the occurrence of bone cement leakage in PVP and PKP.%目的:为胸腰椎(T8~L5)椎体成形术减少骨水泥渗漏等并发症提供解剖学依据。方法对40例健康成人胸腰椎螺旋CT薄层扫描和重建,观察每节段正中矢状位和横断位图像上椎基静脉孔(basivertebral foramen, BF)和椎体静脉孔道(vertebral vein, VV)出现的频率;测量椎体正中矢状径(VD)和BF宽(BFW)、深(BFD)高(BFH);测量BF距椎体左右缘距离(VW1和VW2)和距上下终板的距离(VH1和VH2),应用Stata7.0统计学软件包对上述数据进行统计学分析。结果 BF

  17. The Preparation and Gas Sensitive Research of M-Cresol Purple-PVP Composite Film/K+Ion-Exchanged Glass Optical Waveguide Sensor%间甲酚紫-PVP复合薄膜/K+交换玻璃光波导元件的制备及其气敏研究

    Institute of Scientific and Technical Information of China (English)

    朱敏; 阿布力孜·伊米提

    2015-01-01

    M-cresol purple-polyvinylpyrrolidone(m-CP-PVP)composite film components was fixed on K+glass opti-cal waveguide surface with the method of spin-coating. We studied the UV-visible absorption spectrum variation of the different compound ratio of m-cresol purple-polyvinylpyrrolidone composite film/K+exchange glass optical wave-guide sensor before and after reacting with acidic and volatile organic compounds gases,and on the basis of study-ing the sensor response of acidic and volatile organic compounds gases in the optical waveguide detection system. The sensitive film was changed from yellow to red when it reacted with acidic gases. The sensor can detect H 2S with the volume concentration which is lower than 1×10-10(1.41×10-4 mg/m3),response and recovery time are 1.1 s and 8.5 s,andS/N is 15.43;and SO2 is lower than 1×10-10(2.66×10-4 mg/m3),response and recovery time are 0.4 s and 2.7 s,and S/N is 5.88. Meanwhile,the thickness of m-CP-PVP composite film is 199 nm±5 nm.%利用旋转甩涂法(Spin-Coating)将间甲酚紫-聚乙烯吡咯烷酮复合薄膜固定在K+交换玻璃光波导表面研制了光波导敏感元件.研究了不同复合比例的间甲酚紫-聚乙烯吡咯烷酮复合薄膜与酸性和挥发性有机气体作用前后的紫外可见吸收光谱变化,并在此基础上研究了该敏感元件在光波导测试系统中对酸性和挥发性有机气体的响应.敏感薄膜与酸性气体作用后,薄膜由黄色变为紫红色.该敏感元件能检测到体积比浓度低于1×10-10(1.41×10-4 mg/m3)的H2S,响应和恢复时间分别为1.1 s和8.5 s,信噪比S/N为15.43;能检测到体积比浓度低于1×10-10(2.66×10-4 mg/m3)SO2气体,响应和恢复时间分别为0.4 s和2.7 s,信噪比S/N为5.88.间甲酚紫-聚乙烯吡咯烷酮复合薄膜厚度为199 nm±5 nm.

  18. Third-order optical nonlinearities of PVP/Pd nanohybrids

    Science.gov (United States)

    Papagiannouli, I.; Potamianos, D.; Krasia-Christoforou, T.; Couris, S.

    2017-10-01

    Pd nanoparticles stabilized by polyvinylpyrrolidone were synthesized following mild reduction of palladium ion complexes. Their morphology and optical properties were characterized using Transmission Electron Microscopy, Dynamic Light Scattering and UV-Vis absorption spectroscopy to confirm the existence of monodispersed, low-dimensional single nanoparticles. Furthermore, their third-order nonlinear optical properties were investigated by means of the Z-scan technique, using 35 ps and 4 ns laser pulses, both in the visible (532 nm) and in the infrared (1064 nm). These results denote that the surface plasmon resonance is not significantly contributing to the nonlinear optical response of Pd nanoparticles. In contrast, a two photon absorption process was found to contribute to the observed response. The present results are discussed and compared with previous literature findings.

  19. Computer technology -- 1996: Applications and methodology. PVP-Volume 326

    Energy Technology Data Exchange (ETDEWEB)

    Hulbert, G.M. [ed.] [Univ. of Michigan, Ann Arbor, MI (United States); Hsu, K.H. [ed.] [Babcock and Wilcox, Barberton, OH (United States); Lee, T.W. [ed.] [FMC Corp., Santa Clara, CA (United States); Nicholas, T. [ed.] [USAF Wright Laboratory, Wright-Patterson AFB, OH (United States)

    1996-12-01

    The primary objective of the Computer Technology Committee of the ASME Pressure Vessels and Piping Division is to promote interest and technical exchange in the field of computer technology, related to the design and analysis of pressure vessels and piping. The topics included in this volume are: analysis of bolted joints; nonlinear analysis, applications and methodology; finite element analysis and applications; and behavior of materials. Separate abstracts were prepared for 23 of the papers in this volume.

  20. Preparation of PVP hydrogel nanoparticles using lecithin vesicles

    Directory of Open Access Journals (Sweden)

    Vânia Blasques Bueno

    2010-01-01

    Full Text Available Hydrogels micro, sub-micro and nanoparticles are of great interest for drug encapsulation and delivery or as embolotherapic agents. In this work it is described the preparation of nano and sub-microparticles of pre-formed, high molecular weight and monomer free poly(N-vinyl-2-pyrrolidone encapsulated inside the core of lecithin vesicles. The hydrogel particles are formed with a very narrow diameter distribution, of about 800 nm, and a moderate swelling ratio, of approximately 10.

  1. Influence of PVP/VA copolymer composition on drug-polymer solubility

    DEFF Research Database (Denmark)

    Rask, Malte Bille; Knopp, Matthias Manne; Olesen, Niels Erik

    2016-01-01

    interacting with a VP repeat unit hinders another CCX molecule from binding to the neighboring repeat units in the polymer chain. Therefore, it is possible that replacing these neighboring hygroscopic VP repeat units with hydrophobic VA repeat units, could increase the physical stability of an amorphous solid...

  2. Structural and nonlinear optical characterizations of ZnS/ PVP nanocomposites synthesized by pulsed laser ablation

    Science.gov (United States)

    Divyasree, M. C.; Chandrasekharan, K.

    2017-05-01

    ZnS/Poly Vinyl Pyrrolidone nanocomposites were synthesized by pulsed laser ablation at ambient conditions using an Nd: YAG laser at 532 nm wavelength and 7ns pulse width. Linear optical characterizations were done using UV-Vis spectrophotometer and fluorometer. Both absorption and emission peaks were found to be blue shifted, which could be due to quantum confinement effect. Spherical morphology and the purity in the elemental composition of the sample were confirmed by scanning electron microscope and energy dispersive X-ray spectrometer respectively. Average particle size of the ZnS nanoparticles was found to be 13.45 nm from the Gaussian fitted histogram of transmission electron Microscopy image and the structure was confirmed as hexagonal wurtzite by X-ray diffraction analysis. The nonlinear optical parameters were figured out by z scan analysis with the same laser system. The nanocomposite showed good absorptive and refractive properties in the nonlinear optical regime. Detailed study of the nanocomposite revealed its potential applications in optoelectronics and nonlinear optical device fabrication.

  3. Effect of Hemorrhage on Cardiac Output, PVP, Alodosterone and Diuresis during Immersion in Men

    Science.gov (United States)

    Simanonok, K.; Greenleaf, John E.; Bernauer, E. M.; Wade, C. E.; Keil, L. C.

    1990-01-01

    The purpose of this study was to test the hypothesis that a reduction in blood volume would attenuate or eliminate immersion-induced increases in cardiac output (Q (sup dot) sub co)) and urine excretion, and to investigate accompanying vasoactive and fluid-electrolyte hormonal responses.

  4. Thermal Processing of PVP- and HPMC-Based Amorphous Solid Dispersions

    OpenAIRE

    LaFountaine, Justin S.; Prasad, Leena Kumari; Brough, Chris; Miller, Dave A.; McGinity, James W.; Williams, Robert O.

    2015-01-01

    Thermal processing technologies continue to gain interest in pharmaceutical manufacturing. However, the types and grades of polymers that can be utilized in common thermal processing technologies, such as hot-melt extrusion (HME), are often limited by thermal or rheological factors. The objectives of the present study were to compare and contrast two thermal processing methods, HME and KinetiSol® Dispersing (KSD), and investigate the influence of polymer type, polymer molecular weight, and dr...

  5. Antimicrobial activity of electrospun poly(butylenes succinate) fiber mats containing PVP-capped silver nanoparticles.

    Science.gov (United States)

    Tian, Ligang; Wang, Pingli; Zhao, Zhiguo; Ji, Junhui

    2013-12-01

    In this study, biodegradable poly(butylenes succinate) (PBS) fiber mats containing silver nanoparticles (AgNPs) were prepared by the electrospinning process. Small AgNPs (fiber mats and the distribution of the AgNPs were well characterized by TEM and SEM. The release of Ag from the PBS fiber mats was quantitively determined by ICP. The PBS fiber mats with 0.29 % AgNPs content showed strong antimicrobial activity against both gram-positive Staphylococcus aureus and gram-negative Escherichia coli with the efficacy as high as 99 %. The effective bactericidal activity on E. coli was demonstrated for a short contacting time with the PBS-AgNPs fiber mats. In addition, the long-term release performance of Ag from the fiber mats can keep inhibiting the bacterial growth in the mats over a long period of time.

  6. Submicronic VO2–PVP composites coatings for smart windows applications and solar heat management

    CSIR Research Space (South Africa)

    Madida, IG

    2014-09-01

    Full Text Available (sup2) of coated windows worldwide with smart coatings, energy saving in the building and automotive economic fields is equivalent of CO(sub2) reduction by about ~100 millions of tons....

  7. Measurement of Ultraviolet Radiation Exposure Using Methylene Blue and PvP

    Science.gov (United States)

    Deantonio, Michael

    2004-10-01

    This study was performed to create a device that can detect UV radiation levels in an attempt to lower the skin cancer rates in the Southwest United States. An Ultraviolet sensitive dye was combined with a polymer and the absorption was measured. With the help of Dr. Mike DeAntonio and Dr. Amanda Ellis, the students at Mesilla Valley Christain School did the experiments and recorded data on the UV absorption. This method was found to enable the public to monitor Ultraviolet absorption on the skin. And so, it is expected to reduce the rate of skin cancer. The students entered this project into a nation-wide competition called E-Cybermission and received a prize for second place in the Southwest Region.

  8. PREPERATION AND IN VITRO EVALUATION OF SOLID DISPERSIONS OF NIMODIPINE USING PEG 4000 AND PVP K3

    Directory of Open Access Journals (Sweden)

    ADINARAYANA GORAJANA, ADHIYAMAN RAJENDRA NALAMOLU KOTESWARA RAO

    2013-09-01

    Full Text Available Solid dispersions in water-soluble carriers have attracted considerable interest as a means of improving the dissolution rate, and hence possibly bioavailability, of a range of hydrophobic drugs. The aim of the present study was to improve the solubility and dissolution rate of a poorly water-soluble drug, nimodipine, by a solid dispersion technique. Solid dispersions were prepared by using polyethylene glycol 4000 (PEG- 4000 and polyvinylpyrrolidone K30 (PVPK30 in different drug-to-carrier ratios. The solid dispersions were prepared by melting method. Morphology of solid dispersions was characterised by scanning electron microscope. The pure drug, physical mixtures and solid dispersions were characterized by in vitro dissolution study. Dissolution characteristics were determined by using pH 4.5 acetate buffer containing 0.3% SDS. The very slow dissolution rate was observed for pure nimodipine and the dispersion of the drug in the polymers considerably enhanced the dissolution rate. This can be attributed to improved wettability and dispersibility, as well as decrease of the crystalline and increase of the amorphous fraction of the drug. Solid dispersions prepared with PEG-4000 and PVPK30 showed the highest improvement in wettability and dissolution rate of nimodipine. Even physical mixtures of nimodipine prepared with both polymers also showed better dissolution profile than that of pure nimodipine. In conclusion, dissolution of nimodipine can be enhanced by the use of hydrophilic carriers PEG-4000 and PVPK30.

  9. Binding constants of inclusion complexes of nitroimidazoles with {beta}-cyclodextrins in the absence and presence of PVP

    Energy Technology Data Exchange (ETDEWEB)

    Chadha, Renu [University Institute of Pharmaceutical Sciences, Panjab University, Chandigarh 160014 (India)]. E-mail: renukchadha2004@yahoo.co.in; Jain, D.V.S. [Depatment of Chemistry, Panjab University, Chandigarh 160014 (India); Aggarwal, Amit [University Institute of Pharmaceutical Sciences, Panjab University, Chandigarh 160014 (India); Singh, Surjit [GND University, Amritsar, Panjab (India); Thakur, Deepika [University Institute of Pharmaceutical Sciences, Panjab University, Chandigarh 160014 (India)

    2007-07-01

    Thermodynamics of complexation of 5-nitroimidazoles with {beta}-cyclodextrin and its methylated and hydroxypropyl derivatives in water and in 0.25% polyvinylpyrrolidone are determined by solution calorimetry. A 1:1 stoichiometry was established. The equilibrium constant (K) for all the nitroimidazoles fall in the range 1000-1900 M{sup -1} suitable for use of cyclodextrins as drug carriers. The complexation ability is significantly enhanced by methylation of the {beta}-cyclodextrin. The stability constant increased in the order metronidazole < ornidazole < tinidazole < secnidazole. The presence of polyvinylpyrrolidone enhances the stability constants.

  10. Micro-Holograms in a Methyl Red-Doped Polymer-Dispersed Liquid Crystal (E48:PVP

    Directory of Open Access Journals (Sweden)

    N. P. Hermosa II

    2003-06-01

    Full Text Available Feasibility of a holographic point-by-point storage in a methyl red-doped Polymer-Dispersed LiquidCrystal (PDLC is determined. Micro-holograms (gratings are recorded next to each other. Smallestgrating diameter obtained is 69.9 mm, with minimum grating distance of 80 mm. Recording of adjacentgrating reduces the diffraction efficiency of existing grating by 17% (average.

  11. Formation and Biopharmaceutical Characterization of Electrospun PVP Mats with Propolis and Silver Nanoparticles for Fast Releasing Wound Dressing

    Directory of Open Access Journals (Sweden)

    Erika Adomavičiūtė

    2016-01-01

    Full Text Available Antibacterial, antiviral, antifungal, antioxidant, anti-inflammatory, and anticancer activities of propolis and its ability to stimulate the immune system and promote wound healing make it a proper component for wound dressing materials. Silver nanoparticles are recognized to demonstrate strong antiseptic and antimicrobial activity; thus, it also could be considered in the development of products for wound healing. Combining propolis and silver nanoparticles can result in improved characteristics of products designed for wound healing and care. The aim of this study was to formulate electrospun fast dissolving mats for wound dressing containing propolis ethanolic extract and silver nanoparticles. Produced electrospun nano/microfiber mats were evaluated studying their structure, dissolution rate, release of propolis phenolic compounds and silver nanoparticles, and antimicrobial activity. Biopharmaceutical characterization of electrospun mats demonstrated fast release of propolis phenolic compounds and silver nanoparticles. Evaluation of antimicrobial activity on Staphylococcus aureus, Staphylococcus epidermidis, Enterococcus faecalis, Escherichia coli, Pseudomonas aeruginosa, Proteus vulgaris, Bacillus subtilis, Bacillus cereus, and Candida albicans strains confirmed the ability of electrospun mats to inhibit the growth of the tested microorganisms.

  12. Formation and Biopharmaceutical Characterization of Electrospun PVP Mats with Propolis and Silver Nanoparticles for Fast Releasing Wound Dressing.

    Science.gov (United States)

    Adomavičiūtė, Erika; Stanys, Sigitas; Žilius, Modestas; Juškaitė, Vaida; Pavilonis, Alvydas; Briedis, Vitalis

    2016-01-01

    Antibacterial, antiviral, antifungal, antioxidant, anti-inflammatory, and anticancer activities of propolis and its ability to stimulate the immune system and promote wound healing make it a proper component for wound dressing materials. Silver nanoparticles are recognized to demonstrate strong antiseptic and antimicrobial activity; thus, it also could be considered in the development of products for wound healing. Combining propolis and silver nanoparticles can result in improved characteristics of products designed for wound healing and care. The aim of this study was to formulate electrospun fast dissolving mats for wound dressing containing propolis ethanolic extract and silver nanoparticles. Produced electrospun nano/microfiber mats were evaluated studying their structure, dissolution rate, release of propolis phenolic compounds and silver nanoparticles, and antimicrobial activity. Biopharmaceutical characterization of electrospun mats demonstrated fast release of propolis phenolic compounds and silver nanoparticles. Evaluation of antimicrobial activity on Staphylococcus aureus, Staphylococcus epidermidis, Enterococcus faecalis, Escherichia coli, Pseudomonas aeruginosa, Proteus vulgaris, Bacillus subtilis, Bacillus cereus, and Candida albicans strains confirmed the ability of electrospun mats to inhibit the growth of the tested microorganisms.

  13. Investigation of the degree of homogeneity and hydrogen bonding in PEG/PVP blends prepared in supercritical CO2: comparison with ethanol-cast blends and physical mixtures

    CSIR Research Space (South Africa)

    Labuschagne, Philip W

    2010-07-01

    Full Text Available stream_source_info John1_2010.pdf.txt stream_content_type text/plain stream_size 37726 Content-Encoding UTF-8 stream_name John1_2010.pdf.txt Content-Type text/plain; charset=UTF-8 Investigation of the degree.... Reference List [1] Kazarian SG, Vincent MF, Bright FV, Liotta CL, Eckert CA. Specific intermolecular interaction of carbon dioxide with polymers. Journal of the American Chemical Society 1996; 118: 1729-1736. [2] Kazarian SG. Polymer processing...

  14. Mass transfer and thermodynamics during immersion precipitation for a two-polymer system: Evaluation with the system PES-PVP-NMP-water

    NARCIS (Netherlands)

    Boom, R.M.; Boom, R.M.; van den Boomgaard, Anthonie; Smolders, C.A.; Smolders, C.A.

    1994-01-01

    An extended version of the mass transfer model by Reuvers et al. for a four-component system is evaluated, which is shown to be generally valid for short times. The thermodynamics under these circumstances are evaluated, together with the kinetics. Initial composition paths (concentration profiles)

  15. Innovative hydrogels based on semi-interpenetrating p(HEMA)/PVP networks for the cleaning of water-sensitive cultural heritage artifacts.

    Science.gov (United States)

    Domingues, Joana A L; Bonelli, Nicole; Giorgi, Rodorico; Fratini, Emiliano; Gorel, Florence; Baglioni, Piero

    2013-02-26

    Water-based detergent systems offer several advantages, over organic solvents, for the cleaning of cultural heritage artifacts in terms of selectivity and gentle removal of grime materials or aged varnish, which are known to alter the readability of the painting. Unfortunately, easel paintings present specific characteristics that make the usage of water-based systems invasive. The interaction of water with wood or canvas support favors mechanical stresses between the substrate and the paint layers leading to the detachment of the pictorial layer. In order to avoid painting loss and to ensure a fine control (layer by layer) of grime removal, water-based cleaning systems have been confined into innovative chemical hydrogels, specifically designed for cleaning water-sensitive cultural heritage artifacts. The synthesized hydrogels are based on semi-interpenetrating chemical poly(2-hydroxyethyl methacrylate)/poly(vinylpyrrolidone) networks with suitable hydrophilicity, water retention properties, and required mechanical strength to avoid residues after the cleaning treatment. Three different compositions were selected. Water retention and release properties have been studied by quantifying the amount of free and bound water (from differential scanning calorimetry); mesoporosity was obtained from scanning electron microscopy; microstructure from small angle X-ray scattering. To demonstrate both the efficiency and versatility of the selected hydrogels in confining and modulating the properties of cleaning systems, a representative case study is presented.

  16. Characterization of mature maize (Zea mays L.) root system architecture and complexity in a diverse set of Ex-PVP inbreds and hybrids.

    Science.gov (United States)

    Hauck, Andrew L; Novais, Joana; Grift, Tony E; Bohn, Martin O

    2015-01-01

    The mature root system is a vital plant organ, which is critical to plant performance. Commercial maize (Zea mays L.) breeding has resulted in a steady increase in plant performance over time, along with noticeable changes in above ground vegetative traits, but the corresponding changes in the root system are not presently known. In this study, roughly 2500 core root systems from field trials of a set of 10 diverse elite inbreds formerly protected by Plant Variety Protection plus B73 and Mo17 and the 66 diallel intercrosses among them were evaluated for root traits using high throughput image-based phenotyping. Overall root architecture was modeled by root angle (RA) and stem diameter (SD), while root complexity, the amount of root branching, was quantified using fractal analysis to obtain values for fractal dimension (FD) and fractal abundance (FA). For each trait, per se line effects were highly significant and the most important contributor to trait performance. Mid-parent heterosis and specific combining ability was also highly significant for FD, FA, and RA, while none of the traits showed significant general combining ability. The interaction between the environment and the additive line effect was also significant for all traits. Within the inbred and hybrid generations, FD and FA were highly correlated (rp ≥ 0.74), SD was moderately correlated to FD and FA (0.69 ≥ rp ≥ 0.48), while the correlation between RA and other traits was low (0.13 ≥ rp ≥ -0.40). Inbreds with contrasting effects on complexity and architecture traits were observed, suggesting that root complexity and architecture traits are inherited independently. A more comprehensive understanding of the maize root system and the way it interacts with the environment will be useful for defining adaptation to nutrient acquisition and tolerance to stress from drought and high plant densities, critical factors in the yield gains of modern hybrids.

  17. Effect of antigravity suit inflation on cardiovascular, PRA, and PVP responses in humans. [Plasma Renin Activity and Plasma VasoPressin

    Science.gov (United States)

    Kravik, S. E.; Keil, L. C.; Geelen, G.; Wade, C. E.; Barnes, P. R.

    1986-01-01

    The effects of lower body and abdominal pressure, produced by antigravity suit inflation, on blood pressure, pulse rate, fluid and electrolyte shift, plasma vasopressin and plasma renin activity in humans in upright postures were studied. Five men and two women stood upright for 3 hr with the suit being either inflated or uninflated. In the control tests, the suit was inflated only during the latter part of the trials. Monitoring was carried out with a sphygnomanometer, with sensors for pulse rates, and using a photometer and osmometer to measure blood serum characteristics. The tests confirmed earlier findings that the anti-g suit eliminates increases in plasma renin activity. Also, the headward redistribution of blood obtained in the tests commends the anti-g suit as an alternative to water immersion or bed rest for initial weightlessness studies.

  18. Highly Efficient Adsorption of Copp er Ions by a PVP-Reduced Graphene Oxide Based On a New Adsorptions Mechanism

    Institute of Scientific and Technical Information of China (English)

    Yongji Zhang; HuiJuan Chi; WenHui Zhang; Youyi Sun; Qing Liang; Yu Gu; Riya Jing

    2014-01-01

    Polyvinylpyrrolidone-reduced graphene oxide was prepared by modified hummers method and was used as adsorbent for removing Cu ions from wastewater. The effects of contact time and ions concentration on adsorption capacity were examined. The maximum adsorption capacity of 1689 mg/g was observed at an initial pH value of 3.5 after agitating for 10 min. It was demonstrated that polyvinylpyrrolidone-reduced graphene oxide had a huge adsorption capacity for Cu ions, which was 10 times higher than maximal value reported in previous works. The adsorption mechanism was also discussed by density functional theory. It demonstrates that Cu ions are attracted to surface of reduced graphene oxide by C atoms in reduced graphene oxide modified by polyvinylpyrrolidone through physisorption processes, which may be responsible for the higher adsorption capacity. Our results suggest that polyvinylpyrrolidone-reduced graphene oxide is an effective adsorbent for removing Cu ions in wastewater. It also provides a new way to improve the adsorption capacity of reduced graphene oxide for dealing with the heavy metal ion in wastewater.

  19. Characterization of the P140K, PVP(138-140)MLK, and G156A O6-methylguanine-DNA methyltransferase mutants: implications for drug resistance gene therapy.

    Science.gov (United States)

    Davis, B M; Roth, J C; Liu, L; Xu-Welliver, M; Pegg, A E; Gerson, S L

    1999-11-20

    The G156A O6-alkylguanine-DNA alkyltransferase (AGT) mutant protein, encoded by the G156A O6-methylguanine-DNA methyltransferase gene (MGMT), is resistant to O6-benzylguanine (BG) inactivation and, after transduction into hematopoietic progenitors, transmits remarkable resistance to BG and BCNU. As a result, a clinical trial, in which the MGMT gene is transduced into CD34+ cells of patients with cancer, has been approved. A newly identified AGT mutation, P140K, generates dramatically increased BG resistance relative to G156A, and suggests that gene transfer of P140K may confer improved hematopoietic cell protection. To address this hypothesis, we measured BG + BCNU and BG + TMZ resistance in G156A, P140K, or P138M/V139L/P140K (MLK) MGMT-transduced K562 cells. In addition, we performed a detailed characterization of individual properties including BG resistance, activity, and protein stability of these mutants in human hematopoetic K562 cells and E86 retroviral producer cells. In K562 cell extracts, the MLK and P140K mutants retained full activity at doses up to 1 mM BG, while G156A had a BG ED50 of 15 microM, compared with 0.1 microM for wtAGT. In the absence of BG, the G156A protein possessed a 56% reduction in specific O6-methyltransferase activity compared with wtAGT. MLK, P140K, and wtAGT all possessed similar specific activities, although the O6-methyl repair rate of all mutants was reduced 4- to 13-fold relative to wtAGT. The wtAGT, MLK, and P140K proteins were stable, with half-lives of greater than 18 hr. In contrast, only 20% of the G156A protein was stable after 12 hr in cycloheximide and, interestingly, the remaining protein appeared to retain most of the activity present in non-cycloheximide-treated cells. Differences in BG resistance, activity, and stability between P140K, MLK, and G156A suggest that P140K may be the optimal mutant for drug resistance gene transfer. However, hematopoietic K562 cells transduced with MFG-G156A, P140K, or MLK had similar degrees of BG and BCNU as well as BG and TMZ resistance when treated with concentrations of BG (< or =25 microM) achieved in clinical trials, suggesting similar efficacy in many in vivo applications.

  20. Characterization of mature maize (Zea mays L.) root system architecture and complexity in a diverse set of Ex-PVP inbreds and hybrids

    National Research Council Canada - National Science Library

    Hauck, Andrew L; Novais, Joana; Grift, Tony E; Bohn, Martin O

    2015-01-01

    .... In this study, roughly 2500 core root systems from field trials of a set of 10 diverse elite inbreds formerly protected by Plant Variety Protection plus B73 and Mo17 and the 66 diallel intercrosses...

  1. Synthesis of PVP stabilized Cu/Pd nanoparticles with citrate complexing agent and its application as an activator for electroless copper deposition.

    Science.gov (United States)

    Lo, Sylvia H Y; Wang, Yung-Yun; Wan, Chi-Chao

    2007-06-01

    A simple method has been developed to synthesize Cu/Pd nanoparticles in aqueous solution in ambient condition with the addition of complexing agent, trisodium citrate. UV-vis spectra confirmed the complexing behavior of trisodium citrate and metal ions. The particles synthesized with trisodium citrate were well dispersed with particle size ranging between 3-4 nm while the particles without trisodium citrate were larger and aggregated, as demonstrated by transmission electron microscopy (TEM). X-ray diffraction patterns (XRD) indicated the formation of bimetallic nanoparticles without impurities in the complexing agent-supplemented system. In contrast, large amounts of PdO and Cu(OH)(2) were precipitated along with the formation of particles in the complexing agent-free system. X-ray photoelectron spectroscopy (XPS) revealed small amounts of oxidized Pd on the surface of particles and the existence of zerovalent Cu and oxidized Cu in particles with trisodium citrate. With a simpler process for electroless copper deposition, the Cu/Pd nanoparticle activator with less Pd metal used exhibited comparable catalytic activity to conventional Pd/Sn colloidal activator. In summary, application of Cu/Pd nanoparticles synthesized with the complexing agent as an activator suggested a novel, simpler and inexpensive process in PCB industry.

  2. Efficacy of a Solution Composed by Verbascoside, Polyvinylpyrrolidone (PVP) and Sodium Hyaluronate in the Treatment of Chemotherapy-induced Oral Mucositis in Children With Acute Lymphoblastic Leukemia.

    Science.gov (United States)

    Bardellini, Elena; Amadori, Francesca; Schumacher, Richard Fabian; D'Ippolito, Carmelita; Porta, Fulvio; Majorana, Alessandra

    2016-10-01

    The aim of this study was to assess the efficacy of a solution composed by verbascoside, polyvinylpyrrolidone, and sodium hyaluronate (Mucosyte) in the treatment of chemotherapy-induced oral mucositi (OM). Patients between 5 and 18 years receiving chemotherapy for acute lymphoblastic leukemia and with OM grade 1 or 2 were randomized in group A (treated with Mucosyte, 3 mouthwashes/d per 8 d) and group B (treated with placebo, ie, an inert water-based solution, 3 mouthwashes/d per 8 d). The OM scoring was performed at day 1 (diagnosis of OM-T0), after 3 days of treatment (T1), and at day 8 (T2). Pain was evaluated through the visual analog scale with the same timing of OM measurement. A total of 56 patients were included (28 patients per group). Group A experienced a statistically significant decline of OM at T2 (P=0.0038); a statistically significant difference in pain reduction between 2 groups both at T1 and at T2 (P<0.005) was observed. The use of Mucosyte mouthwashes in children with chemotherapy-induced OM may be recommended as supportive therapy.

  3. Polivinilpirrolidona-iodo (PVP-I em base aquosa na antissepsia de campo operatório oftálmico de cães Water-soluble polyvinylpyrrolidone-iodine (PVP-I on concentrations of 0.1% and 0.5% in antisepsis of dogs ophthalmic surgery

    Directory of Open Access Journals (Sweden)

    Priscilla Santos Bagbed Pithon

    2010-12-01

    Full Text Available Com o presente trabalho, objetivou-se comparar o efeito bactericida do polivinilpirrolidona-iodo nas concentrações a 0,1% e 0,5% sobre a antissepsia do campo operatório oftálmico de cães. Foram utilizados 20 cães e soluções em concentrações diferentes para cada olho. No olho direito, utilizou-se solução de polivinilpirrolidona-iodo a 0,1% e no olho esquerdo a 0,5%. A colheita da amostra conjuntival de ambos os grupos foi realizada antes da antissepsia (0, após 30 minutos (1, 1,5 horas (2 e 2,5 horas (3 da irrigação e limpeza. Foi identificado crescimento bacteriano em 70% das amostras oculares colhidas antes da antissepsia. Os agentes bacterianos encontrados nos diferentes tempos de colheita foram Staphylococcus intermedis, Staphylococcus aureus, Staphylococcus sp., Staphylococcus epidermidis, Bacillus sp., Difteróide, Enterobacter sp., Micrococcus sp. A solução de polivinilpirrolidona-iodo a 0,1% diminuiu em 64% e 50% o crescimento de bactérias após 30min (1 e 90min da antissepsia (2, respectivamente. Enquanto a concentração 0,5% reduziu em 86%, houve crescimento bacteriano de 71%, o que indicou um maior poder inibitório sobre o crescimento bacteriano. Dessa maneira, a solução de polivinilpirrolidona-iodo a 0,5%, em relação à solução a 0,1%, mostrou-se mais eficaz na redução da microbiota conjuntival até 90min após a antissepsia.The objective of this study was to compare the bactericide effect of polyvinylpyrrolidone-iodine at concentrations of 0.1% and 0.5% on antisepsis of dog ophthalmic region. Solutions with different concentrations were used on each eye of twenty dogs. On the right eye, the 0.1% solution was administered and, on the left eye, the 0.5% solution. Conjunctival sampling of both groups was performed before antisepsis (0, after 30 minutes (1, 1.5h (2 and 2.5h (3 of irrigation and cleaning. Bacterial growth was identified in 70% of ocular sample collected before the antisepsis. The bacterial agents found on different times of sampling were Staphylococcus intermedius, Staphylococcus aureus, Staphylococcus sp., Staphylococcus epidermidis, Bacillus sp. Diphtheroids, Enterobacter sp., Micrococcus sp. The 0.1% solution of polyvinylpyrrolidone-iodine decreased by 64% and 50% bacteria growth after 1 and 2, respectively. The group that used the concentration of polyvinylpyrrolidone-iodine 0.5% showed greater bactericide power. Therefore, the solution of polyvinylpyrrolidone-iodine to 0.5% compared to 0.1% solution was more effective in reduction of the conjunctival microbiota up to 90min after antisepsis.

  4. Multifunctional e-spun colloidal nanofiber structures from various dispersed blends of PVA/ODA-MMT with PVP/ODA-MMT, poly(VP-alt-MA and AgNPs incorporated polymer complexes as electro-active platforms

    Directory of Open Access Journals (Sweden)

    U. Bunyatova

    2016-07-01

    Full Text Available This work presented a new approach to fabricate polymer nanocomposites films with nanofiber structures from solution blends of poly(vinyl alcohol + octadecyl amine-montmorillonite (ODA-MMT (matrix with poly(N-vinylpyrrolidone + ODA-MMT (partner-1, poly(N-vinylpyrrolidone-alt-maleic anhydride ((poly(VP-alt-MA + (ODA-MMT (partner-2 and their silver (Ag-carrying polymer complexes by electrospinning. Chemical and physical structures, surface morphologies, thermal behaviors, electrical conductivity and thermal resistance parameters of nanofiber structures were investigated. Poly(VP-alt-MA was used both as a crosslinker and a donor of the hydrophilic groups such as ‒COOH and ‒NH–C=O amide from pyrrolidone ring. Reactive poly(VP-alt-MA, in situ generated Ag nanoparticles (AgNPs and original partner polymer had an significant effect on the morphology and diameter distribution of nanofibers. High and excellent conductive behaviors were observed for the homopolymer and copolymer of VP based fiber structures, respectively. Upon successive chemical cross-linking of the nanofiber structures by reactive partner copolymer, the conductivity of nanofiber films as electro-active platforms dramatically increased to 3.90·10–2 S·cm–1 at room temperature. Comparative analysis results also indicated that electrical properties strongly depended on the loaded reactive organoclay and in situ generated AgNPs.

  5. The Influence of PVP and PEG on Piroxicam β-Cyclodextyin Inclusion Action%聚维酮和聚乙二醇对吡罗昔康-β-环糊精包合的影响

    Institute of Scientific and Technical Information of China (English)

    王齐放; 修锐; 赵哲; 郭晶; 苏德森

    2000-01-01

    研究了聚乙烯吡咯烷酮(PVPK-30)和聚乙二醇(PEG-4000)对吡罗昔康-β-环糊精包合作用的影响,用热力学的方法求出了包合物在高聚物存在下的热力学函数.结果表明,吡罗昔康-β-环糊精包合物在PVP和PEG的存在下包合反应表观稳定常数(KC)增大,包合反应的自由焓(ΔG)减小.高聚物的最佳浓度为3~5 g /L.

  6. STUDY ON THE INTERACTION BETWEEN POLYVINYLPYRROLIDONE AND PLATINUM METALS DURING THE FORMATION OF THE COLLOIDAL METAL NANOPARTICLES

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Several PVP-stabilized colloidal platinum metals nanoparticles have been synthesized and characterized by FTIR and TEM.Comparing with the pure PVP,carbonyl groups of PVP in the mixture of PVP and the metal precursors or in the PVP-stabilized metal nanoparticles have obvious peak shifts in FTIR spectra.The peak shifts reveal the interaction between PVP and the metal species.The interaction between PVP and metal precursors has effect on the formation of the colloidal metal nanoparticles.Strength of the interaction between PVP and metal nanoparticles has direct influence on the stability and the size of the PVP-stabilized metal nanoparticles.Therein,species of the metal precursors and amount of the stabilizer are main factors on the strength of the interaction.

  7. The Effect of Polyvinylpyrrolidone on the Optical Properties of the Ni-Doped ZnS Nanocrystalline Thin Films Synthesized by Chemical Method

    Directory of Open Access Journals (Sweden)

    Tran Minh Thi

    2012-01-01

    Full Text Available We report the optical properties of polyvinyl-pyrrolidone (PVP and the influence of PVP concentration on the photoluminescence spectra of the PVP (PL coated ZnS : Ni nanocrystalline thin films synthesized by the wet chemical method and spin-coating. PL spectra of samples were clearly showed that the 520 nm luminescence peak position of samples remains unchanged, but their peak intensity changes with PVP concentration. The PVP polymer is emissive with peak maximum at 394 nm with the exciting wavelength of 325 nm. The photoluminescence exciting (PLE spectrum of PVP recorded at 394 nm emission shows peak maximum at 332 nm. This excitation band is attributed to the electronic transitions in PVP molecular orbitals. The absorption edges of the PVP-coated ZnS : Ni0.3% samples that were shifted towards shorter wavelength with increasing of PVP concentration can be explained by the absorption of PVP in range of 350 nm to 400 nm. While the PVP coating does not affect the microstructure of ZnS : Ni nanomaterial, the analyzed results of the PL, PLE, and time-resolved PL spectra and luminescence decay curves of the PVP and PVP-coated ZnS : Ni samples allow to explain the energy transition process from surface PVP molecules to the Ni2+ centers that occurs via hot ZnS.

  8. Spray coating as a powerful technique in preparation of solid dispersions with enhanced desloratadine dissolution rate.

    Science.gov (United States)

    Kolašinac, Nemanja; Kachrimanis, Kyriakos; Djuriš, Jelena; Homšek, Irena; Grujić, Branka; Ibrić, Svetlana

    2013-07-01

    Solid dispersion systems have been widely used to enhance dissolution rate and oral bioavailability of poorly water-soluble drugs. However, the formulation process development and scale-up present a number of difficulties which has greatly limited their commercial applications. In this study, solid dispersions (SDs) of desloratadine (DSL) with povidone (PVP) and crospovidone (cPVP) were prepared by spray coating technique. The process involved the spray application of 96% ethanol solution of DSL and PVP/cPVP, and subsequent deposition of the coprecipitates onto microcrystalline cellulose pellets during drying by air flow in a mini spray coater. The results from the present study demonstrated that the spray coating process is efficient in preparing SDs with enhanced drug dissolution rate and it is highly efficient in organic solvent removal. Both PVP and cPVP greatly improved drug dissolution rate by SDs, with PVP showing better solubilization capability. Very fast drug dissolution rate is achieved from SDs containing PVP regardless of differences in K grade. SD with smaller particles of cPVP have higher drug dissolution rate in comparison to the cPVP with larger particles. Results from physical state characterization indicate that DSL in SDs exist in the amorphous (high free-energy) state which is probably stabilized by PVP/cPVP. After 6-month accelerated stability study, DSL remains amorphous, while PVP and cPVP act as anti-plasticizing agents, offering efficient steric hindrance for nucleation and crystal growth.

  9. UV and cold tolerance of a pigment-producing Antarctic Janthinobacterium sp. Ant5-2

    KAUST Repository

    Mojib, Nazia

    2013-03-20

    In this paper, we describe the UV and cold tolerance of a purple violet pigment (PVP)-producing Antarctic bacterium, Janthinobacterium sp. Ant5-2 (PVP+) and compared its physiological adaptations with a pigmentless mutant strain (PVP-). A spontaneous deletion of vioA that codes for tryptophan monooxygenase, the first gene involved in the biosynthesis of PVP was found in PVP- strain. The PVP- culture exhibited significantly reduced survival during exponential and stationary growth phase following exposure to UVB (320 nm) and UVC (254 nm) (dose range: 0-300 J/m2) when compared to wild-type (PVP+) cultures. In addition, upon biochemical inhibition of pigment synthesis by 2(5H)-furanone, wild-type PVP+ cultures exhibited approximately 50-fold growth reduction at a higher dose (300 J/m2) of UV. Increased resistance to UV was observed upon inducing starvation state in both PVP+ and PVP- cultures. There was 80 % (SD = ±8) reduction in extrapolymeric substance (EPS) production in the PVP- cultures along with a compromised survival to freeze-thaw cycles when compared to the PVP+ cultures. Perhaps synthesis of PVP and EPS are among the key adaptive features that define the survival of this bacterium in Antarctic extreme conditions, especially during austral summer months. © 2013 Springer Japan.

  10. Dynamic Model and Control of a Photovoltaic Generation System using Energetic Macroscopic Representation

    Science.gov (United States)

    Solano, Javier; Duarte, José; Vargas, Erwin; Cabrera, Jhon; Jácome, Andrés; Botero, Mónica; Rey, Juan

    2016-10-01

    This paper addresses the Energetic Macroscopic Representation EMR, the modelling and the control of photovoltaic panel PVP generation systems for simulation purposes. The model of the PVP considers the variations on irradiance and temperature. A maximum power point tracking MPPT algorithm is considered to control the power converter. A novel EMR is proposed to consider the dynamic model of the PVP with variations in the irradiance and the temperature. The EMR is evaluated through simulations of a PVP generation system.

  11. Percutaneous vertebroplasty: technical considerations

    Institute of Scientific and Technical Information of China (English)

    Gao-jun TENG; Shi-cheng HE

    2005-01-01

    Percutaneous vertebroplasty (PVP) is a relative new interventional technique, which is widely used in treatment of vertebral collapse caused by vertebral neoplasms and osteoporotic compression fractures. The general technical considerations of PVP techniques are discussed based on authors' experience obtained over 400 patients in the past years in this article, including preparation of PMMA, instrument of PVP, guidance and puncture approaches, and technique of the procedure, etc. The conclusion is that PVP is a safe procedure if the physicians handle it properly.

  12. Distribution of binder in granules produced by means of twin screw granulation

    DEFF Research Database (Denmark)

    Fonteyne, Margot; Fussell, Andrew Luke; Vercruysse, Jurgen

    2014-01-01

    -granular distribution of PVP was evaluated by means of hyperspectral coherent anti-Stokes Raman scattering (CARS) microscopy. For the evaluated formulation, no PVP rich zones were detected when applying a lateral spatial resolution of 0.5 μm, indicating that PVP is homogenously distributed within the granules....

  13. Improvement of blood compatibility on polysulfone-polyvinylpyrrolidone blend films as a model membrane of dialyzer by physical adsorption of recombinant soluble human thrombomodulin (ART-123).

    Science.gov (United States)

    Omichi, Masaaki; Matsusaki, Michiya; Maruyama, Ikuro; Akashi, Mitsuru

    2012-01-01

    ART-123 is a recombinant soluble human thrombomodulin (hTM) with potent anticoagulant activity, and is available for developing antithrombogenic surfaces by immobilization. We focused on improving blood compatibility on the dialyzer surface by the physical adsorption of ART-123 as a safe yet simple method without using chemical reagents. The physical adsorption mechanism and anticoagulant activities of adsorbed hTM on the surface of a polysulfone (PSF) membrane containing polyvinylpyrrolidone (PVP) as a model dialyzer were investigated in detail. The PVP content of the PSF-PVP films was saturated at 20 wt% after immersion in Tris-HCl buffer, even with the addition of over 20 wt% PVP. The surface morphology of the PSF-PVP films was strongly influenced by the PVP content, because PVP covered the outermost surface of the PSF-PVP films. The adsorption speed of hTM slowed dramatically with increasing PVP content up to 10 wt%, but the maximum adsorption amount of hTM onto the PSF-PVP film surface was almost the same, regardless of the PVP content. The PSF-PVP film with the physically adsorbed hTM showed higher protein C activity as compared to the PSF film, it showed excellent blood compatibility due to the protein C activity and the inhibition properties of platelet adhesion. The physical adsorption of hTM can be useful as a safe yet simple method to improve the blood compatibility of a dialyzer surface.

  14. Efficiency enhancement of polymer solar cells by applying poly(vinylpyrrolidone) as a cathode buffer layer via spin coating or self-assembly.

    Science.gov (United States)

    Wang, Haitao; Zhang, Wenfeng; Xu, Chenhui; Bi, Xianghong; Chen, Boxue; Yang, Shangfeng

    2013-01-01

    A non-conjugated polymer poly(vinylpyrrolidone) (PVP) was applied as a new cathode buffer layer in P3HT:PCBM bulk heterojunction polymer solar cells (BHJ-PSCs), by means of either spin coating or self-assembly, resulting in significant efficiency enhancement. For the case of incorporation of PVP by spin coating, power conversion efficiency (PCE) of the ITO/PEDOT:PSS/P3HT:PCBM/PVP/Al BHJ-PSC device (3.90%) is enhanced by 29% under the optimum PVP spin-coating speed of 3000 rpm, which leads to the optimum thickness of PVP layer of ~3 nm. Such an efficiency enhancement is found to be primarily due to the increase of the short-circuit current (J(sc)) (31% enhancement), suggesting that the charge collection increases upon the incorporation of a PVP cathode buffer layer, which originates from the conjunct effects of the formation of a dipole layer between P3HT:PCBM active layer and Al electrodes, the chemical reactions of PVP molecules with Al atoms, and the increase of the roughness of the top Al film. Incorporation of PVP layer by doping PVP directly into the P3HT:PCBM active layer leads to an enhancement of PCE by 13% under the optimum PVP doping ratio of 3%, and this is interpreted by the migration of PVP molecules to the surface of the active layer via self-assembly, resulting in the formation of the PVP cathode buffer layer. While the formation of the PVP cathode buffer layer is fulfilled by both fabrication methods (spin coating and self-assembly), the dependence of the enhancement of the device performance on the thickness of the PVP cathode buffer layer formed by self-assembly or spin coating is different, because of the different aggregation microstructures of the PVP interlayer.

  15. Polyvinylpyrrolidone adsorption effects on the morphologies of synthesized platinum particles and its catalytic activity

    Energy Technology Data Exchange (ETDEWEB)

    Ooi, Mahayatun Dayana Johan [Nano - Optoelectronic Research and Technology Laboratory, School of Physics, Universiti Sains Malaysia, 11800, Minden, Pulau Pinang (Malaysia); Aziz, Azlan Abdul [Nano - Optoelectronic Research and Technology Laboratory, School of Physics, Universiti Sains Malaysia, 11800, Minden, Pulau Pinang (Malaysia); Nanobiotechnology Research and Innovation (NanoBRI), INFORMM, Universiti Sains Malaysia, 11800, Minden, Pulau Pinang (Malaysia)

    2015-04-24

    Flower-like Platinum micro-structures were synthesized from different concentration of the PVP using solvothermal method. At 5.0×10{sup −3} mmol of PVP, well-defined flower-like pattern consists of triangular petals radiating from the centre were produced whereas larger flower network developed at higher PVP concentration. High degree of crystallinity was obtained upon each increment of PVP. The well defined flower like pattern synthesized using 5.0×10{sup −3} mmol PVP exhibit the highest catalytic activity and stability towards electro-oxidation of formic acid.

  16. Two-photon laser fabrication of three-dimensional silver microstructures with submicron scale linewidth

    Energy Technology Data Exchange (ETDEWEB)

    Tsutsumi, Naoto; Nagata, Kazuya; Sakai, Wataru [Kyoto Institute of Technology, Department of Macromolecular Science and Engineering, Graduate School of Science and Technology, Kyoto (Japan)

    2011-05-15

    We show three-dimensional silver microstructures with a submicron scale linewidth fabricated via two-photon photoreduction of silver ions in a poly(N-vinylpyrrolidone) (PVP) matrix. Femtosecond laser at 508 nm directly excites the carbonyl group of PVP via two-photon excitation to reduce silver ions. Lone pair electrons in PVP stabilized silver ions and lower molecular weight of PVP prevented silver clusters growing larger. The effect of molecular weight of PVP on linewidth of silver nanowire is investigated. (orig.)

  17. Polyvinylpyrrolidone adsorption effects on the morphologies of synthesized platinum particles and its catalytic activity

    Science.gov (United States)

    Ooi, Mahayatun Dayana Johan; Aziz, Azlan Abdul

    2015-04-01

    Flower-like Platinum micro-structures were synthesized from different concentration of the PVP using solvothermal method. At 5.0×10-3 mmol of PVP, well-defined flower-like pattern consists of triangular petals radiating from the centre were produced whereas larger flower network developed at higher PVP concentration. High degree of crystallinity was obtained upon each increment of PVP. The well defined flower like pattern synthesized using 5.0×10-3 mmol PVP exhibit the highest catalytic activity and stability towards electro-oxidation of formic acid.

  18. Predicting kinetic nanocrystal shapes through multi-scale theory and simulation: Polyvinylpyrrolidone-mediated growth of Ag nanocrystals.

    Science.gov (United States)

    Balankura, Tonnam; Qi, Xin; Zhou, Ya; Fichthorn, Kristen A

    2016-10-14

    In the shape-controlled synthesis of colloidal Ag nanocrystals, structure-directing agents, particularly polyvinylpyrrolidone (PVP), are known to be a key additive in making nanostructures with well-defined shapes. Although many Ag nanocrystals have been successfully synthesized using PVP, the mechanism by which PVP actuates shape control remains elusive. Here, we present a multi-scale theoretical framework for kinetic Wulff shape predictions that accounts for the chemical environment, which we used to probe the kinetic influence of the adsorbed PVP film. Within this framework, we use umbrella-sampling molecular dynamics simulations to calculate the potential of mean force and diffusion coefficient profiles of Ag atom deposition onto Ag(100) and Ag(111) in ethylene glycol solution with surface-adsorbed PVP. We use these profiles to calculate the mean-first passage times and implement extensive Brownian dynamics simulations, which allows the kinetic effects to be quantitatively evaluated. Our results show that PVP films can regulate the flux of Ag atoms to be greater towards Ag(111) than Ag(100). PVP's preferential binding towards Ag(100) over Ag(111) gives PVP its flux-regulating capabilities through the lower free-energy barrier of Ag atoms to cross the lower-density PVP film on Ag(111) and enhanced Ag trapping by the extended PVP film on Ag(111). Under kinetic control, {100}-faceted nanocrystals will be formed when the Ag flux is greater towards Ag(111). The predicted kinetic Wulff shapes are in agreement with the analogous experimental system.

  19. Effect of poly(vinyl pyrrolidone) on the morphology and physical properties of poly(vinyl alcohol)/sodium montmorillonite nanocomposite films

    Institute of Scientific and Technical Information of China (English)

    Dibyendu Mondal; Md. Masud R. Mollick; Biplab Bhowmick; Dipanwita Maity; Mrinal K. Bain; Dipak Rana; Asis Mukhopadhyay; Kausik Dana; Dipankar Chattopadhyay

    2013-01-01

    Nanocomposites of poly(vinyl alcohol) (PVA), poly(vinyl pyrrolidone) (PVP) and sodium montmorillonite (NaþMMT) were prepared by solution mixing and then cast into films. X-ray diffraction analysis and images of transmission electron microscopy establish the formation of PVA/NaþMMT intercalated nanocomposite. Exfoliated and highly intercalated PVA/PVP/NaþMMT nanocomposite formed in the presence of PVP. Inclusion of PVP in PVA/NaþMMT matrix enhances the hydrogen bonding interactions between PVA and NaþMMT and thus increases the mechanical properties and thermal stability of PVA/PVP/NaþMMT nanocomposites compared to PVA/NaþMMT nanocomposite. The interactions between PVA, PVP and NaþMMT were established by the Fourier transform infrared spectroscopy. The moisture absorption tendency of both the PVA and PVA/PVP films reduced after the incorporation of NaþMMT at 75% constant relative humidity. Differential scanning calorimetry studies show that the presence of PVP and NaþMMT both are responsible for reducing the heat of fusion, and crystallinity of PVA. The flow behavior of the PVA, PVA/PVP and its nanocomposite solutions has been also studied. Water vapor permeability of PVA/PVP/NatMMT composite films decreased in the presence of nanoclay due to increasing tortuous paths for diffusion.

  20. Highly methanol-tolerant platinum electrocatalyst derived from poly(vinylpoyrrolidone) coating

    Science.gov (United States)

    Yang, Zehui; Ling, Ying; Zhang, Yunfeng; Yang, Ming

    2017-02-01

    The design and fabrication of a methanol-tolerant electrocatalyst is still one of the most important issues in direct methanol fuel cells (DMFCs). Here, we focus on the design of a cathodic electrocatalyst in DMFCs and describe a new methanol-tolerant electrocatalyst fabricated from poly(vinylpyrrolidone) (PVP) coating on platinum nanoparticles assisted by hydrogen bonding between PVP and polybenzimidazole (PBI). The PVP layer has a negligible effect on the oxygen reduction reaction (ORR) activity, while the methanol oxidation reaction is retarded by the PVP layer. The PVP-coated electrocatalyst shows higher ORR activity under various methanol concentrations in the electrolyte, suggesting that the PVP-coated electrocatalyst has a higher methanol tolerance. Also, the PVP-coated electrocatalyst loses only 14% of the electrochemical surface area after 5000 potential cycles from 0.6-1.0 V versus the reversible hydrogen electrode, indicating better Pt stability than non-coated (27%) and commercial (38%) electrocatalysts due to the unique sandwich structure formed by the PVP and PBI. The power density of the PVP-coated electrocatalyst is four to five times higher compared to non-coated and commercial electrocatalysts with 12 M methanol feeding to the anode side, respectively. PVP coating is important for the enhancement of Pt stability and methanol tolerance. This study offers a new method for preparing a low-cost and high-methanol-tolerant Pt electrocatalyst, and useful information for real DMFC application to eliminate the methanol crossover problem in the cathode side.

  1. VISCOMETRIC INVESTIGATIONS OF POLYVINYLPYRROLIDONE IN MIXED SOLVENTS AND WITH VARYING TEMPERATURE

    Institute of Scientific and Technical Information of China (English)

    Omar Melad; Omar Abu-Tiem; Rajai Baraka

    2005-01-01

    The viscosity behavior of polyvinylpyrrolidone (PVP) has been determined at 25℃ in mixed solvents comprising water/dimethylformamide (DMF) and water /methanol (MeOH). Analysis of the data has considered the PVP as being both host and guest polymer in solution. The intrinsic viscosity of PVP in DMF is higher than in water and in MeOH, but also increases in a mixed solvent with high water content because of the effect of polymer-solvent interactions. It was also found that the intrinsic viscosity of PVP at finite concentration, [ηPVP]c decreases with an increase in the concentration of PVP in solution. The viscosity behavior of PVP in a mixed solvent is affected by the concentration-dependent intermolecular excluded volume effect, which can be quantitatively expressed by the parameter, bY, which reflects the shrinkage of PVP chain coils, resulting in a decrease of [ηPVP]c . The effect of temperature on the viscosity behavior of PVP in MeOH shows that the interaction parameter increases up to a maximum value, and then decreases after a certain temperature.

  2. Molecular mechanism of the protective effect of monomer polyvinylpyrrolidone on antioxidants - experimental and computational studies.

    Science.gov (United States)

    Liu, W; Wang, J; Li, M; Tang, W; Han, J

    2016-12-01

    We previously developed a lutein-polyvinylpyrrolidone (PVP) complex with improved aqueous saturation solubility and stability, though the conjugation mechanism is still unclear. In this paper, experiments with astaxanthin-PVP complex and curcumin-PVP complex were carried out, which indicated that PVP could improve the solubility and stability of astaxanthin and curcumin. We aimed to construct a computational model capable of understanding the protective effect in complexes formed between PVP and antioxidants, through which the binding mode of PVP and antioxidants was investigated with molecular modelling in order to obtain the interactions, binding energy, binding site and surface area between PVP and antioxidants. Solubility enhancement was attributed to the H-bonds between PVP and antioxidants, and the saturation solubility was curcumin > lutein > astaxanthin. Binding energy, binding site and surface area were beneficial for the stability of complex, and the stability enhancement was lutein > astaxanthin > curcumin. The experimental results were in agreement with the computational results. Furthermore, we established a method for the exploration of a similar system with other polymer complexes. Additionally, the proposed PVP model could predict the interactions between PVP and various ligands, such as antioxidants and drugs.

  3. 碘伏对垂直阻生(8 8)急性冠周炎不同龈瓣覆盖的作用比较%Comparison of the therapeutic effect of pvp- Ⅰ on acute pericoronitis due to vertical impaction (8 8 ) with diffierent gingival flap cover

    Institute of Scientific and Technical Information of China (English)

    游古莲; 林景春; 周正贵

    2000-01-01

    @@ 有关下颌阻生第三磨牙急性冠周炎的各种研究已有报道[1].本研究就碘伏行冠周冲洗对急性冠周炎不同龈瓣所致急性冠周炎的疗效进行比较,现报告如下.

  4. Novel fluorescent amphiphilic block copolymers: photophysics behavior and interactions with DNA

    Directory of Open Access Journals (Sweden)

    2007-06-01

    Full Text Available In this study, novel amphiphilic fluorescent copolymers poly(N-vinylpyrrolidone-b-poly(N-methacryloyl-N'-(α-naphthylthiourea (PVP-b-PNT were synthesized via ATRP with poly(N-vinylpyrrolidone-Cl as macroinitiator and N-methacryloyl-N'-α-naphthylthiourea (NT as hydrophobic segment. PVP-b-PNT copolymers were characterized by 1H NMR, GPC-MALLS and fluorescence measurements. The aggregation behavior of PVP-b-PNT in water was investigated by transmission electron microscope (TEM and dynamic light scattering (DLS measurement. The photophysics behavior of PVP-b-PNT showed that block copolymer formed strong excimer. The interaction of DNA with the block copolymer made the excimer of block copolymer quench. The cytotoxicity result of PVP-b-PNT in cell culture in vitro indicated that this copolymer PVP-b-PNT had good biocompatibility.

  5. Effect of kappa-carrageenan on the properties of poly(N-vinyl pyrrolidone)/kappa-carrageenan blend hydrogel synthesized by {gamma}-radiation technology

    Energy Technology Data Exchange (ETDEWEB)

    Zhai Maolin E-mail: zkkf@pku.edu.cn; Ha Hongfei; Yoshii, F.; Makuuchi, K

    2000-03-01

    A series of hydrogels in the form of rods were prepared from kappa-carrageenan (KC) and poly (N-vinyl pyrrolidone) (PVP) by gamma radiation with {sup 60}Co {gamma} source at room temperature. The properties of the prepared hydrogels, such as the gel strength, gel fraction and swelling behavior were investigated. Incorporation of KC into the PVP/water system increased obviously the gel strength and equilibrium degree of swelling (EDS) of PVP hydrogel. The experimental analyses showed that the crosslinking reaction of PVP was quicker than the degradation of KC at a low dose (less than 30 kGy), and the degradation of KC was inhibited in the PVP/KC mixture system. So an interpenetrating polymer network (IPN) hydrogel composed of PVP (a chemical crosslinking network) and KC (a physical crosslinking network) was proposed here. The existence of different classes of water in this IPN system was shown by water melting curves using DCS. (author)

  6. Poly (n-vinyl-2-pyrrolidone) gels and dimethyl siloxanes and ethylene oxides copolymers crosslinked by ionizing radiation; Geis de poli (n-vivil-2-pirrolidona) e copolimeros de dimetilsiloxano e oxido de etileno reticulados por radiacao ionizante

    Energy Technology Data Exchange (ETDEWEB)

    Souza, A. [Instituto de Pesquisas Energeticas e Nucleares (IPEN), Sao Paulo, SP (Brazil); Nunes, S.P. [Universidade Estadual de Campinas, SP (Brazil). Inst. de Quimica

    1995-12-31

    Poly(N-vinyl-2-pyrrolidone) (PVP) gels, crosslinked by irradiation, have been used for healing of wounds. In this work, a hydrophilic copolymer (dimethyl siloxanes and ethylene oxy - SEO), is added to PVP to improve the mechanical properties. The characterization was performed by DMA, showing that SEO increases the film flexibility, but an excess can inhibit the PVP crosslinking. Crosslinking with electron beam was more effective than with Co-60 source. (author). 5 refs., 2 figs.

  7. Rate of Unsuspected Malignancy in Patients With Vertebral Compression Fracture Undergoing Percutaneous Vertebroplasty

    DEFF Research Database (Denmark)

    Hansen, Emil Jesper; Simony, Ane; Carreon, Leah Y

    2016-01-01

    : 144 consecutive patients underwent PVP for painful VCF, at the Center for Spine Surgery and Research, Middelfart Hospital. All patients had bone biopsies obtained during the PVP, and these biopsies were sent to the Department for Pathology at Vejle Sygehus for histologic diagnosis. RESULTS: About 144...... PVP as a standard procedure, to insure not to overlook any underlying malignancy despite the MRI-scan, blood analysis, and clinical examination being inconspicuous. LEVEL OF EVIDENCE: 3....

  8. Characterization of Model Polyimide/Silver Interphases Using Surface- Enhanced Raman Scattering

    Science.gov (United States)

    1990-06-01

    investigated SERS from bilayers of polystyrene (PS), diglycidyl ether of bisphenol-A ( DGEBA ), poly (4-vinyl pyridine) (PVP), and poly (styrene sulfonate...PSS). Samples were prepared by spin-coating films of PS, DGEBA , or PVP were spun onto silver island films from dilute solutions and then overcoating...solution. Otherwise, SERS was only observed from the first layer (PS, DGEBA , or PVP) even though the PSS films were strong Raman scatters. These results

  9. Identification of heterotic patterns between expired proprietary, NDSU, and industry shortseason maize inbred lines

    OpenAIRE

    Mohammed A. A. Bari; Carena,Marcelo J; Pereira,Messias G

    2016-01-01

    Abstract Maize (Zea mays L.) inbred lines are under restricted use, protected by Patent and Plant Variety Protection (PVP) laws. Research objectives were i) to identify and validate heterotic groups and patterns, and ii) to determine if ex-PVP lines are useful for continued genetic progress in short-season environments. Three groups of crosses were made following North Carolina Mating Design II (NCII) including 12 NDSU, 24 ex-PVP lines, and seven current industry testers. Hybrids were planted...

  10. Impact of lower body negative pressure induced hypovolemia on peripheral venous pressure waveform parameters in healthy volunteers.

    Science.gov (United States)

    Alian, Aymen A; Galante, Nicholas J; Stachenfeld, Nina S; Silverman, David G; Shelley, Kirk H

    2014-07-01

    Lower body negative pressure (LBNP) creates a reversible hypovolemia by sequestrating blood volume in the lower extremities. This study sought to examine the impact of central hypovolemia on peripheral venous pressure (PVP) waveforms in spontaneously breathing subjects. With IRB approval, 11 healthy subjects underwent progressive LBNP (baseline, -30, -75, and -90 mmHg or until the subject became symptomatic). Each was monitored for heart rate (HR), finger arterial blood pressure (BP), a chest respiratory band and PVP waveforms which are generated from a transduced upper extremity intravenous site. The first subject was excluded from PVP analysis because of technical errors in collecting the venous pressure waveform. PVP waveforms were analyzed to determine venous pulse pressure, mean venous pressure, pulse width, maximum and minimum slope (time domain analysis) together with cardiac and respiratory modulations (frequency domain analysis). No changes of significance were found in the arterial BP values at -30 mmHg LBNP, while there were significant reductions in the PVP waveforms time domain parameters (except for 50% width of the respiration induced modulations) together with modulation of the PVP waveform at the cardiac frequency but not at the respiratory frequency. As the LBNP progressed, arterial systolic BP, mean BP and pulse pressure, PVP parameters and PVP cardiac modulation decreased significantly, while diastolic BP and HR increased significantly. Changes in hemodynamic and PVP waveform parameters reached a maximum during the symptomatic phase. During the recovery phase, there was a significant reduction in HR together with a significant increase in HR variability, mean PVP and PVP cardiac modulation. Thus, in response to mild hypovolemia induced by LBNP, changes in cardiac modulation and other PVP waveform parameters identified hypovolemia before detectable hemodynamic changes.

  11. Robust Ag nanoplate ink for flexible electronics packaging.

    Science.gov (United States)

    Li, Ruo-Zhou; Hu, Anming; Bridges, Denzel; Zhang, Tong; Oakes, Ken D; Peng, Rui; Tumuluri, Uma; Wu, Zili; Feng, Zhili

    2015-04-28

    Nanoinks are currently a topic of heightened interest with respect to low temperature bonding processes and printable electronics. We have developed an innovative polyvinylpyrrolidone (PVP)-stabilized Ag nanoplate ink amenable to very strong low temperature packaging, and investigated the relationship between bonding strength and electrical conductivity post-bonding. PVP shell plastic deformations observed in failure microcracks with the formation of PVP nanofibers, revealed bonding strength at low temperatures (packaging, and diverse sensing applications.

  12. Direct electrospinning of Ag/polyvinylpyrrolidone nanocables

    DEFF Research Database (Denmark)

    Chen, Menglin; Havelund, Rasmus; Li, Qiang

    2011-01-01

    Core-sheath silver nanowire/polyvinylpyrrolidone (AgNW/PVP) nanocables have been fabricated via an efficient single-spinneret electrospinning method. The core-sheath structure is revealed by combining several characterization methods. A possible formation mechanism of the AgNW/PVP nanocable...... involving a strong stretching during the electrospinning process is proposed. Further, electrical measurements were performed on AgNW/PVP nanocables as well as bare AgNWs, which indicated the nanocables became insulating due to the isolation of highly conductive AgNWs by insulating PVP sheath. Therefore...

  13. Preparation and surface properties of mesoporous silica particles modified with poly(N-vinyl-2-pyrrolidone) as a potential adsorbent for bilirubin removal

    Energy Technology Data Exchange (ETDEWEB)

    Timin, Alexander, E-mail: a_timin@mail.ru [Inorganic Chemistry Department, Ivanovo State University of Chemistry and Technology (ISUCT), 7, Sheremetevsky prosp., 153000 Ivanovo (Russian Federation); Rumyantsev, Evgeniy, E-mail: evr@isuct.ru [Inorganic Chemistry Department, Ivanovo State University of Chemistry and Technology (ISUCT), 7, Sheremetevsky prosp., 153000 Ivanovo (Russian Federation); Lanin, Sergey N., E-mail: SNLanin@phys.chem.msu.ru [Chemistry Department, Physical Chemistry Division, Lomonosov Moscow State University, 1-3 Leninskie Gory, 119991 Moscow (Russian Federation); Rychkova, Sveta A. [Chemistry Department, Physical Chemistry Division, Lomonosov Moscow State University, 1-3 Leninskie Gory, 119991 Moscow (Russian Federation); Guseynov, Sabir S. [Krestov Institute of Solution Chemistry of Russian Academy of Sciences, 153000 Ivanovo (Russian Federation); Solomonov, Alexey V. [Inorganic Chemistry Department, Ivanovo State University of Chemistry and Technology (ISUCT), 7, Sheremetevsky prosp., 153000 Ivanovo (Russian Federation); Antina, Elena V. [Krestov Institute of Solution Chemistry of Russian Academy of Sciences, 153000 Ivanovo (Russian Federation)

    2014-10-15

    The surface of silica particles was modified with polyvinyl pyrrolidone (PVP) through sol–gel process. The different experimental techniques, i.e., thermogravimetric analysis (TGA and DTG), nitrogen adsorption, scanning electron microscopy (SEM), laser diffraction analysis (LDA), fourier transform spectroscopy (FTIR) are used to characterize the pure non-functionalized and functionalized silicas containing different amount of PVP. It was shown that PVP-modified silica samples have well developed porous structure; the values of specific surface area for PVP-modified silicas are in the range of 140–264 m{sup 2} g{sup −1}. While the non-functionalized silica shows the low surface area (S{sub BET} = 40 m{sup 2} g{sup −1}). The BJH analysis showed that PVP can be used as an effective agent to increase an average pore size and total pore volume. The results indicate that PVP functionalized silicas show a potential as effective adsorbents for bilirubin removal compared to other available adsorbents. - Highlights: • PVP functionalized silicas were synthesized via sol–gel method. • Modification of silica by PVP leads to the formation of mesoporous structure. • PVP functionalized mesoporous silicas demonstrate good adsorption properties for bilirubin removal.

  14. Reinforcing effects of abused 'bath salts' constituents 3,4-methylenedioxypyrovalerone and α-pyrrolidinopentiophenone and their enantiomers.

    Science.gov (United States)

    Gannon, Brenda M; Rice, Kenner C; Collins, Gregory T

    2017-10-01

    Synthetic cathinones found in abused 'bath salts' preparations are chiral molecules. Racemic 3,4-methylenedioxypyrovalerone (MDPV) and α-pyrrolidinopentiophenone (α-PVP) are two common constituents of these preparations that have been reported to be highly effective reinforcers; however, the relative contribution of each enantiomer toward these effects has not been determined. Thus, male Sprague-Dawley rats were trained to respond for racemic MDPV or α-PVP (n=9/drug), with full dose-response curves for the racemate and the S and R enantiomers of MDPV and α-PVP generated under a progressive ratio schedule of reinforcement. Racemic mixtures of both MDPV and α-PVP as well as each enantiomer maintained responding in a dose-dependent manner, with racemic MDPV and α-PVP being equipotent. The rank order of potency within each drug was S enantiomer>racemate ≫ R enantiomer. Although both enantiomers of α-PVP were as effective as racemic α-PVP, R-MDPV was a slightly less effective reinforcer than both S and racemic MDPV. The results of these studies provide clear evidence that both enantiomers of MDPV and α-PVP function as highly effective reinforcers and likely contribute toward the abuse-related effects of 'bath salts' preparations containing racemic MDPV and/or α-PVP.

  15. Fuzzy approach for optimal energy-management of a domestic photovoltaic panel

    Energy Technology Data Exchange (ETDEWEB)

    Chaabene, Maher; Ammar, Mohsen Ben [The High Institute of Technological Studies (ISET), Rte Mahdia Km 2, BP88A, ElBustan, 3099 Sfax (Tunisia); Unite de commande de machines et reseaux de puissance CMERP-ENIS (Tunisia); Elhajjaji, Ahmed [Centre de Robotique, d' electrotechnique et d' automatique CREA (France)

    2007-10-15

    This paper introduces a new switching means giving a real time optimum connection mode of domestic appliances on either the electrical grid or a photovoltaic panel (PVP) output. A fuzzy algorithm makes the decision which ensures the optimal energy-management based on PVP generation and appliances states with respect to energy-saving criteria. Validation is driven on a 1 kW peak (kWp) PVP and domestic appliances of different powers installed at the Energy and Thermal Research Centre (CRTEn) in the north of Tunisia. Results confirm that energy saved during daylight is 80-90% of the PVP generated energy. (author)

  16. Polyvinyl pyrrolidone capped fluorescent anthracene nanoparticles for sensing fluorescein sodium in aqueous solution and analytical application for ophthalmic samples.

    Science.gov (United States)

    Bhopate, Dhanaji P; Mahajan, Prasad G; Garadkar, Kalyanrao M; Kolekar, Govind B; Patil, Shivajirao R

    2015-11-01

    Based on the known complexation ability between polyvinyl pyrrolidone (PVP) and fluorescein sodium (FL Na(+)), fluorescent PVP capped anthracene nanoparticles (PVP-ANPs) were prepared using a reprecipitation method for detection of fluorescein in aqueous solution using the fluorescence resonance energy transfer (FRET) approach. A dynamic light scattering histogram of PVP-ANPs showed narrower particle size distribution and the average particle size was 15 nm. The aggregation-induced enhanced emission (AIEE) of PVP-ANPs was red shifted from its monomer by 1087.22 cm(-1). The maximum emission was seen to occur at 420 nm. The presence of FL Na(+) in the vicinity of PVP-ANPs quenched the fluorescence of PVP-ANPs because of its adsorption on the surface of PVP-ANPs in aqueous suspension. The FL Na(+) and PVP-ANPs were brought close enough, typically to 7.89 nm, which was less than the distance of 10 nm that is required between the energy donor-acceptor molecule for efficient FRET. The quenching results fit into the Stern-Volmer relationship even at temperatures greater than ambient temperatures. The thermodynamic parameters determined from FRET results helped to propose binding mechanisms involving hydrophobic and electrostatic molecular interaction. The fluorescence quenching results were used further to develop an analytical method for estimation of fluorescein sodium from ophthalmic samples available commercially in the market.

  17. Formulation and Evaluation of Prolonged Release Transdermal Drug Delivery System of Telmisartan for the Treatment of Hypertension

    National Research Council Canada - National Science Library

    Asheesh Singh; Parul Singh

    2016-01-01

    .... To fulfill above objective transdermal patches of Telmisartan were prepared by solvent evaporation method using combinations of Eudragit RL100, Ethyl cellulose and PVP in different proportions...

  18. STUDY OF INTERACTION OF DRUGS WITH BODY-ALIKE MACROMOLECULE (POLYVINYLPYRROLIDONE BY ULTRA VIOLET SPECTROSCOPIC METHOD

    Directory of Open Access Journals (Sweden)

    AKHTAR SAEED

    2006-01-01

    Full Text Available UV-visible spectrophotometric technique was used to study the interaction of polyvinylpyrrolidone (PVP with co-solutes: phenol, benzoic acid, sodium benzoate, salicylic acid and acetyl salicylic acid in aqueous medium. Changes in the absorption spectra of the co-solutes were observed in the presence of PVP from 200 to 210 nm. The changes were attributed to interaction of PVP molecules with the co-solute molecules. As the concentration of the co-solute increased, a red shift in the bands was observed indicating an increase in interaction between PVP and the co-solute.

  19. Electrospun polyvinyl alcohol-polyvinyl pyrrolidone nanofibrous membranes for interactive wound dressing application.

    Science.gov (United States)

    Shankhwar, Nisha; Kumar, Manishekhar; Mandal, Biman B; Robi, P S; Srinivasan, A

    2016-01-01

    Cross-linked polyvinyl alcohol (PVA) and polyvinyl pyrrolidone (PVP) composite nanofibrous membranes have been prepared by electrospinning. Mechanical properties of the membranes improved significantly with PVP addition. PVP improved hydrophilicity and sustainable degradation of the membranes. Biocompatibility of the membranes was assessed by in vitro culture of native skin cells (L929 fibroblast and HaCaT keratinocytes). Tests showed sustained release of the antibiotic ciprofloxacin hydrochloride monohydrate by the membranes. Further, zone of inhibition study against Staphylococcus aureus growth demonstrated protective action against external pathogenic microbes. These studies show these simple PVA-PVP nanofibrous membranes are promising interactive antibiotic-eluting wound dressing materials.

  20. Preparation and characterization of Ag nanoparticle-embedded polymer electrospun nanofibers

    Energy Technology Data Exchange (ETDEWEB)

    Dong Guoping, E-mail: guoping_dong@163.com; Xiao Xiudi; Liu, Xiaofeng; Qian Bin [Chinese Academy of Sciences, Shanghai Institute of Optics and Fine Mechanics (China); Ma Zhijun; Ye Song [Zhejiang University, State Key Laboratory of Silicon Materials (China); Chen Danping [Chinese Academy of Sciences, Shanghai Institute of Optics and Fine Mechanics (China); Qiu Jianrong, E-mail: jrqiu@zju.edu.c [Zhejiang University, State Key Laboratory of Silicon Materials (China)

    2010-05-15

    Poly (vinyl alcohol) (PVA) and poly (vinyl pyrrolidone) (PVP) nanofibers embedding Ag nanoparticles (5-18 nm) have been prepared successfully by electrospinning at room temperature. Scanning electron microscope (SEM), X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), Fourier transform IR spectra (FTIR), and Raman scattering were used to characterize the structure and properties of Ag nanoparticle-embedded PVA and PVP nanofibers before and after heat treatment at different temperature. The antibacterial activity of Ag nanoparticle-embedded PVP nanofibers after heat treatment was also tested, which indicated that the biological activity of yeast cells was effectively inhibited by these Ag nanoparticle-embedded PVP nanofibers.

  1. Ionization of covalent immobilized poly(4-vinylphenol) monolayers measured by ellipsometry, QCM and SPR

    Energy Technology Data Exchange (ETDEWEB)

    Uppalapati, Suji [Department of Chemistry, University of Massachusetts Lowell, 1 University Ave., Lowell, MA 01854 (United States); Kong, Na; Norberg, Oscar [KTH-Royal Institute of Technology, Department of Chemistry, Teknikringen 30, S-10044 Stockholm (Sweden); Ramström, Olof, E-mail: ramstrom@kth.se [KTH-Royal Institute of Technology, Department of Chemistry, Teknikringen 30, S-10044 Stockholm (Sweden); Yan, Mingdi, E-mail: Mingdi_Yan@uml.edu [Department of Chemistry, University of Massachusetts Lowell, 1 University Ave., Lowell, MA 01854 (United States); KTH-Royal Institute of Technology, Department of Chemistry, Teknikringen 30, S-10044 Stockholm (Sweden)

    2015-07-15

    Covalently immobilized poly(4-vinylphenol) (PVP) monolayer films were fabricated by spin coating PVP on perfluorophenyl azide (PFPA)-functionalized surfaces followed by UV irradiation. The pH-responsive behavior of these PVP ultrathin films was evaluated by ellipsometry, quartz crystal microbalance (QCM) and surface plasmon resonance (SPR). By monitoring the responses of these films to pH in situ, the ionization constant of the monolayer thin films was obtained. The apparent pK{sub a} value of these covalently immobilized PVP monolayers, 13.4 by SPR, was 3 units higher than that of the free polymer in aqueous solution.

  2. Lotus-leaf-like structured chitosan–polyvinyl pyrrolidone films as an anti-adhesion barrier

    Energy Technology Data Exchange (ETDEWEB)

    Lim, Jin Ik; Kang, Min Ji; Lee, Woo-Kul, E-mail: leewo@dankook.ac.kr

    2014-11-30

    Highlights: • Improved mechanical properties by hydrogen bond between chitosan and PVP chains. • Improved anti-adhesion effect by lotus-leaf-like structured chitosan–PVP (L-chitosan–PVP) film. • L-Chitosan–PVP film as a blood/tissue anti-adhesion barrier for post-surgical treatment. - Abstract: For postsurgical anti-adhesion barrier applications, lotus-leaf-like structured chitosan–PVP films were prepared using a solution casting method with dodecyltrichloro-immobilized SiO{sub 2} nanoparticles. We evaluated whether the lotus-leaf-like structured chitosan–PVP films (L-chitosan–PVP) could be applied as postsurgical anti-adhesion barriers. A recovery test using a tensile strength testing machine and measurement of crystallinity using X-ray diffraction indicated that films with 75% PVP were the optimal composition of the chitosan–PVP films. Also, dodecyltrichloro-immobilized SiO{sub 2} nanoparticles were synthesized and sprayed on the film after pretreatment with the instant bio-glue. Analysis of cell adhesion, proliferation, and anti-thrombus efficiency were performed via a WST assay, field emission scanning electron microscopy, and hemacytometry. The contact angle with the lotus-leaf-like surface was of approximately 150°. Furthermore, the L-chitosan–PVP film yielded a lower cell and platelet adhesion rate (around less than 4%) than that yielded by the untreated film. These results indicate that the lotus-leaf-like structure has a unique property and that this novel L-chitosan–PVP film can be applied as a blood/tissue-compatible, biodegradable material for implantable medical devices that need an anti-adhesion barrier.

  3. Effect of polyvinylpyrrolidone on mesoporous silica morphology and esterification of lauric acid with 1-butanol catalyzed by immobilized enzyme

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Jinyu; Zhou, Guowei, E-mail: guoweizhou@hotmail.com; Jiang, Bin; Zhao, Minnan; Zhang, Yan

    2014-05-01

    Mesoporous silica materials with a range of morphology evolution, i.e., from curved rod-shaped mesoporous silica to straight rod-shaped mesoporous silica, were successfully prepared using polyvinylpyrrolidone (PVP) and triblock copolymer as dual template. The effects of PVP molecular weight and concentration on mesoporous silica structure parameters were studied. Results showed that surface area and pore volume continuously decreased with increased PVP molecular weight. Mesoporous silica prepared with PVP K30 also possessed larger pore diameter, interplanar spacing (d{sub 100}), and cell parameter (a{sub 0}) than that prepared with PVP K15 and PVP K90. In addition, with increased PVP concentration, d{sub 100} and a{sub 0} continuously decreased. The mechanism of morphology evolution caused by the change in PVP concentration was investigated. The conversion rate of lauric acid with 1-butanol catalyzed by immobilized Porcine pancreatic lipase (PPL) was also evaluated. Results showed that PPL immobilized on amino-functionalized straight rod-shaped mesoporous silica maintained 50% of its esterification conversion rate even after five cycles of use with a maximum conversion rate was about 90.15%. - Graphical abstract: Curved rod-shaped mesoporous silica can be obtained at low and the highest PVP concentration, while straight rod-shaped mesoporous silica can be obtained at higher PVP concentration. - Highlights: • Mesoporous silica with morphology evolution from CRMS to SRMS were prepared. • Effects of PVP molecular weight and concentration on silica morphology were studied. • A possible mechanism for the formation of morphology evolution SiO{sub 2} was proposed. • Esterification of lauric acid with 1-butanol catalyzed by immobilized PPL.

  4. Removal of polyvinylpyrrolidone from wastewater using different methods.

    Science.gov (United States)

    Julinová, Markéta; Kupec, Jan; Houser, Josef; Slavík, Roman; Marusincová, Hana; Cervenáková, Lenka; Klívar, Stanislav

    2012-12-01

    Polyvinylpyrrolidone (PVP) is a frequently used polymer in the pharmaceutical and foodstuff industries. Because it is not subject to metabolic changes and is virtually nondegradable, trace concentrations of PVP are often found in community wastewaters. The literature finds that the partial removal of PVP in wastewater treatment plants probably occurs through sorption. The primary objective of this study was to find an effective method to remove PVP from wastewaters. In this regard, the literature indicates the theoretical potential to use specific enzymes (e.g., gamma-lactamases, amidases) to gradually degrade PVP molecules. Polyvinylpyrrolidone biodegradability tests were conducted using suitable heterogeneous cultures (activated sludge) collected from a conventional wastewater treatment plant, treatment plants connected to a pharmaceutical factory, and using select enzymes. Aerobic biodegradation of PVP in a conventional wastewater environment was ineffective, even after adaptation of activated sludge using the nearly identical monomer 1-methyl-2-pyrrolidone. Another potential method for PVP removal involves pretreating the polymer prior to biological degradation. Based on the results (approximately 10 to 15% biodegradation), pretreatment was partially effective, realistically, it could only be applied with difficulty at wastewater treatment plants. Sorption of PVP to an active carbon sorbent (Chezacarb S), which corresponded to the Langmuir isotherm, and sorption to activated sludge, which corresponded to the Freundlich isotherm, were also evaluated. From these sorption tests, it can be concluded that the considerable adsorption of PVP to activated sludge occurred primarily at low PVP concentrations. Based on the test results, the authors recommend the following methods for PVP removal from wastewater: (1) sorption; (2) application of specific microorganisms; and (3) alkaline hydrolysis, which is the least suitable of the three for use in wastewater treatment

  5. Multifunctional chitosan/polyvinyl pyrrolidone/45S5 Bioglass® scaffolds for MC3T3-E1 cell stimulation and drug release.

    Science.gov (United States)

    Yao, Qingqing; Li, Wei; Yu, Shanshan; Ma, Liwei; Jin, Dayong; Boccaccini, Aldo R; Liu, Yong

    2015-11-01

    Novel chitosan-polyvinyl pyrrolidone/45S5 Bioglass® (CS-PVP/BG) scaffolds were prepared via foam replication and chemical cross-linking techniques. The pristine BG, CS-PVP coated BG and genipin cross-linked CS-PVP/BG (G-CS-PVP/BG) scaffolds were synthesized and characterized in terms of chemical composition, physical structure and morphology respectively. Resistance to enzymatic degradation of the scaffold is improved significantly with the use of genipin cross-linked CS-PVP. The bio-effects of scaffolds on MC3T3-E1 osteoblast-like cells were evaluated by studying cell viability, adhesion and proliferation. The CCK-8 assay shows that cell viability on the resulting G-CS-PVP/BG scaffold is improved obviously after cross-linking of genipin. Cell skeleton images exhibit that well-stretched F-actin bundles are obtained on the G-CS-PVP/BG scaffold. SEM results present significant improvement on the cell adhesion and proliferation for cells cultured on the G-CS-PVP/BG scaffold. The drug release performance on the as-synthesized scaffold was studied in a phosphate buffered saline (PBS) solution. Vancomycin is found to be released in burst fashion within 24h from the pristine BG scaffold, however, the release period from the G-CS-PVP/BG scaffold is enhanced to 7days, indicating improved drug release properties of the G-CS-PVP/BG scaffold. Our results suggest that the G-CS-PVP/BG scaffolds possess promising physicochemical properties, sustained drug release capability and good biocompatibility for MC3T3-E1 cells' proliferation and adhesion, suggesting their potential applications in areas such as MC3T3-E1 cell stimulation and bone tissue engineering.

  6. Preparation of polyvinylpyrrodione microspheres by dispersion polymerization

    Institute of Scientific and Technical Information of China (English)

    Linfeng ZHAI; Tiejun SHI; Hualin WANG

    2009-01-01

    The preparation of polyvinylpyrrolidone (PVP) microspheres in ethyl acetate by dispersion polymerization with N-vinylpyrrolidone (NVP) as initial monomer, poly(N-vinylpyrrolidone-co-vinyl acetate) (P (NVP-co-VAc)) as dispersant, and 2, 2'-azobisisobutyr-onitrile(AIBN) as initiator is reported. The influences of monomer concentration, dispersant concentration and initiator concentration on the size of PVP microspheres as well as the monomer conversion were studied. The structure and properties of PVP microspheres were analyzed. The results show that the prepared PVP micro-spheres have a mean diameter of 3-4 μm. With an increase in NVP concentration, the size and the molecular weight of the PVP microspheres as well as the monomer conversion all increase. With increasing P(NVP-co-VAc) concentra-tions, the PVP molecular weight and monomer conversion both increase while the size of the microspheres becomes smaller. As the concentration of AIBN increases, the microsphere size and monomer conversion increase whereas the PVP molecular weight decreases. The PVP prepared by dispersion polymerization has a crystal structure, and its molecular weight is lower compared to that prepared by solution polymerization.

  7. Deep sedation in GreenLight laser prostatectomy

    Directory of Open Access Journals (Sweden)

    Fotini Fligou

    2016-01-01

    Conclusion: The combined use of ketamine and propofol for the performance of PVP proved to be an efficient method for anesthesia. The “deep sedation” provided by these drugs was not associated with significant side-effects. Moreover, the use of the above method is indicated in patients with significant co-morbidities that should undergo PVP.

  8. Toxicity, Bioaccumulation and Biotransformation of Silver Nanoparticles in Marine Organisms

    Science.gov (United States)

    The toxicity, bioaccumulation and biotransformation of citrate and polyvinylpyrrolidone (PVP) capped silver nanoparticles (NPs) (AgNP-citrate and AgNP-PVP) and titanium dioxide (TiO2) NPs in marine organisms via marine sediment exposure were investigated. Results from 7-d sedimen...

  9. Microcontainers - an oral drug delivery system for poorly soluble drugs

    DEFF Research Database (Denmark)

    Nielsen, Line Hagner; Petersen, Ritika Singh; Marizza, Paolo

    with polyvinylpyrrolidone (PVP) by inkjet printing followed by supercritical CO2 impregnation of ketoprofen into the PVP matrix. As an alternative filling method, the powder of amorphous sodium salt of furosemide, (ASSF) was filled into the SU-8 microcontainers. The PLLA microcontainers were filled with drug formulation...

  10. Effect of polyvinylpyrrolidone on mesoporous silica morphology and esterification of lauric acid with 1-butanol catalyzed by immobilized enzyme

    Science.gov (United States)

    Zhang, Jinyu; Zhou, Guowei; Jiang, Bin; Zhao, Minnan; Zhang, Yan

    2014-05-01

    Mesoporous silica materials with a range of morphology evolution, i.e., from curved rod-shaped mesoporous silica to straight rod-shaped mesoporous silica, were successfully prepared using polyvinylpyrrolidone (PVP) and triblock copolymer as dual template. The effects of PVP molecular weight and concentration on mesoporous silica structure parameters were studied. Results showed that surface area and pore volume continuously decreased with increased PVP molecular weight. Mesoporous silica prepared with PVP K30 also possessed larger pore diameter, interplanar spacing (d100), and cell parameter (a0) than that prepared with PVP K15 and PVP K90. In addition, with increased PVP concentration, d100 and a0 continuously decreased. The mechanism of morphology evolution caused by the change in PVP concentration was investigated. The conversion rate of lauric acid with 1-butanol catalyzed by immobilized Porcine pancreatic lipase (PPL) was also evaluated. Results showed that PPL immobilized on amino-functionalized straight rod-shaped mesoporous silica maintained 50% of its esterification conversion rate even after five cycles of use with a maximum conversion rate was about 90.15%.

  11. In vitro antimicrobial activity of solution blow spun poly(lactic acid)/ polyvinylpyrrolidone nanofibers loaded with Copaiba (Copaifera sp.) oil

    Science.gov (United States)

    In this study poly(lactic acid)(PLA) and polyvinylpyrrolidone (PVP) micro and nanofibers mats loaded with copaiba (Copaifera sp.) oil were produced by solution blow spinning (SBS). The copaiba (Copaifera sp.) oil was characterized by gas chromatography (GC). Neat PLA and four PLA/ PVP blends contain...

  12. Characterization of the molecular distribution of drugs in glassy solid dispersions at the nano-meter scale, using differential scanning calorimetry and gravimetric water vapour sorption techniques

    NARCIS (Netherlands)

    van Drooge, D J; Hinrichs, W L J; Visser, M R; Frijlink, H W

    2006-01-01

    The molecular distribution in fully amorphous solid dispersions consisting of poly(vinylpyrrolidone) (PVP)-diazepam and inulin-diazepam was studied. One glass transition temperature (T-g), as determined by temperature modulated differential scanning calorimetry (TMDSC), was observed in PVP-diazepam

  13. Application of hot melt extrusion to enhance the dissolution and oral bioavailability of oleanolic acid

    Directory of Open Access Journals (Sweden)

    Nannan Gao

    2017-01-01

    Full Text Available The aim of this study was to improve the in vitro dissolution rate and oral bioavailability of oleanolic acid (OA, a water insoluble drug belonging to BCS class IV. Hot melt extrusion (HME was applied to develop OA amorphous solid dispersions. The characterizations of the optimal formulation were performed by differential scanning calorimetry, X-ray powder diffraction, Fourier transform infrared spectroscopy and in vitro dissolution test. The in vivo pharmacokinetic study was conducted in rats. As a result, OA solid dispersion based on PVP VA 64 (OA-PVP was successfully prepared. In the dissolution medium containing 0.3% SDS, OA-PVP dramatically increased the releasing rate of OA compared with the physical mixture (PM-PVP and commercial tablet. Furthermore, OA-PVP exhibited higher AUC (P < 0.05 and Cmax (P < 0.05 than PM-PVP and commercial tablet. The superior dissolution property and bioavailability of OA-PVP mainly attributed to the amorphous state of OA in PVP VA64 and the well dispersion caused by thermal melting and shearing. Overall, hot melt extrusion was an efficient strategy to enhance the dissolution rate and oral bioavailability of OA.

  14. 78 FR 37200 - Plant Variety Protection Board; Open Teleconference Meeting

    Science.gov (United States)

    2013-06-20

    ..., electronic PVP application/computer database development, and the use of molecular markers for PVP... Agricultural Marketing Service Plant Variety Protection Board; Open Teleconference Meeting AGENCY: Agricultural... their opportunity to attend an open meeting of the Plant Variety Protection Board. DATES: July 31,...

  15. Preparation and characterization of dipyridamole solid dispersions for stabilization of supersaturation: effect of precipitation inhibitors type and molecular weight.

    Science.gov (United States)

    Vora, Chintan; Patadia, Riddhish; Mittal, Karan; Mashru, Rajashree

    2016-11-01

    Dipyridamole (DPL) is a weakly basic BCS class II drug which precipitates upon entering into intestine leading to pH dependant and variable absorption. Thus, research envisaged focuses on developing formulations that maintain supersaturation following upon acid to neutral pH transition. In an endeavor to accomplish the objective, solid dispersion (SD) with hydroxypropylmethyl cellulose (HPMC) and polyvinylpyrrolidone (PVP) was prepared by a quench cooling method. The three molecular weight grades of HPMC (HPMC E5, HPMC E15 and HPMC E50) and two molecular weight grades of PVP (PVP K30 and PVP K90) were investigated to observe effect of increasing molecular weight on stabilizing DPL supersaturated solutions. Equilibrium solubility studies revealed increase in solubility with both HPMC and PVP with greater benefit from HPMC. In vitro supersaturated dissolution results demonstrated that HPMC formulations provided greater degree and extent of supersaturation as compared to PVP formulations. The formulation with HPMC E50 provided maximum stabilization to supersaturation upon acid to neutral pH transition. Moreover, the effect of increase in molecular weight was more pronounced in HPMC rather than PVP. Stronger interactions were observed for DPL with HPMC, while no interaction was observed with PVP which was evident from Fourier transform infra-red studies. Differential scanning calorimetry and powder X-ray diffraction studies revealed the amorphous state of DPL in SD.

  16. Adsorption of Polyvinylpyrrolidone and its Impact on Maintenance of Aqueous Supersaturation of Indomethacin via Crystal Growth Inhibition.

    Science.gov (United States)

    Patel, Dhaval D; Anderson, Bradley D

    2015-09-01

    This study explored the adsorption and crystal growth inhibitory effects of polyvinylpyrrolidone (PVP) on indomethacin crystals in an aqueous medium. A solution depletion method was used to construct adsorption isotherms of PVPs with different molecular weights and N-vinylpyrrolidone onto indomethacin crystals. The affinity for and extent of maximum adsorption of PVP on indomethacin crystals were significantly higher than that of N-vinylpyrrolidone, which was attributed to cooperative interactions between PVP and the surface of indomethacin. The extent of PVP adsorption onto indomethacin crystals in terms of mg/m(2) was greater for higher molecular weight PVP but less on a molar basis indicating an increased percentage of loops and tails for the higher molecular weight PVP. PVP significantly inhibited the crystal growth of indomethacin at a high degree of supersaturation as compared with N-vinylpyrrolidone, which was attributed to a change in indomethacin crystal growth mechanism leading to a change in the rate limiting step from bulk diffusion to surface integration. Higher molecular weight PVPs are better inhibitors of the crystal growth of indomethacin than lower molecular weight PVPs, which was attributed in part to a greater barrier for surface diffusion of indomethacin provided by a thicker adsorption layer of PVP. © 2015 Wiley Periodicals, Inc. and the American Pharmacists Association.

  17. Toxicity, Bioaccumulation and Biotransformation of Silver Nanoparticles in Marine Organisms

    Science.gov (United States)

    The toxicity, bioaccumulation and biotransformation of citrate and polyvinylpyrrolidone (PVP) capped silver nanoparticles (NPs) (AgNP-citrate and AgNP-PVP) and titanium dioxide (TiO2) NPs in marine organisms via marine sediment exposure were investigated. Results from 7-d sedimen...

  18. Chemical treatment of membranes of a polymer blend: Mechanism of the reaction of hypochlorite with poly(vinyl pyrrolidone)

    NARCIS (Netherlands)

    Wienk, I.M.; Meuleman, E.E.B.; Borneman, Z.; Boomgaard, van den Th.; Smolders, C.A.

    1995-01-01

    Sodium hypochlorite solutions are used to treat membranes prepared from a polymeric blend containing poly(vinyl pyrrolidone) (PVP) to increase their water permeability. Sodium hypochlorite affects the membrane material in such a way that PVP is selectively removed from the membrane matrix. The mecha

  19. Photocatalytic properties of thin films of ruthenium metallopolymers/gold nanoparticle: Polyoxometalate composites using visible excitation

    Institute of Scientific and Technical Information of China (English)

    朱杰

    2013-01-01

    Thin layers of an electrostatically associated adduct RuPVP-AuNP:POM formed between the polyoxomolybdate, [S2 Mo18 O62 ]4, the polycationic metallopolymer [Ru(bpy)2(PVP)10 ](ClO4)2 and DMAP-protected gold nanoparticle have been deposited onto electrodes using two separate methods, alternate immersion layer-by-layer assembly and pre-assembled drop-casting; PVP is poly(4-vinylpyridine), BPY is 2,2’-bipyridyl, and DMAP is 4-dimethylaminopyridine. Significantly, the efficiency of the photocatalysis depends markedly on the structure of the [RuPVP-AuNP:POM] even when photonic properties are very similar. Strikingly, despite their similar photonic properties, an additional optical transition is observed in UV-vis and the Raman spectra of pre-assembled drop cast [RuPVP-AuNP:POM], which was not seen in dip coated [RuPVP-AuNP:POM]. Importantly, this electronic communication enhances the photocatalytic oxidation of benzaldehyde by a factor of more than four. While there is clear evidence for photosensitisation in the drop cast not present for the dip coated systems, the magnitude of the photocurrent, i.e.,(82.2 6.6) nA·cm 2for pre-assembled drop cast [RuPVP-AuNP:POM] at a ruthenium to Au nanoparticle mole ratio of 48:1, is twice as large as that those found in [Ru-PVP:POM] film.

  20. Stabilisation of amorphous furosemide increases the oral drug bioavailability in rats

    DEFF Research Database (Denmark)

    Nielsen, Line Hagner; Rades, Thomas; Müllertz, Anette

    2015-01-01

    A glass solution of the amorphous sodium salt of furosemide (ASSF) and polyvinylpyrrolidone (PVP) (80: 20 w/w%) was prepared by spray drying. It was investigated if PVP was able to stabilise ASSF during storage and dissolution and whether this influenced the in vivo performance of the glass solut...

  1. Effects of nanoparticle size on cellular uptake and liver MRI with polyvinylpyrrolidone-coated iron oxide nanoparticles.

    Science.gov (United States)

    Huang, Jing; Bu, Lihong; Xie, Jin; Chen, Kai; Cheng, Zhen; Li, Xingguo; Chen, Xiaoyuan

    2010-12-28

    The effect of nanoparticle size (30-120 nm) on magnetic resonance imaging (MRI) of hepatic lesions in vivo has been systematically examined using polyvinylpyrrolidone (PVP)-coated iron oxide nanoparticles (PVP-IOs). Such biocompatible PVP-IOs with different sizes were synthesized by a simple one-pot pyrolysis method. These PVP-IOs exhibited good crystallinity and high T(2) relaxivities, and the relaxivity increased with the size of the magnetic nanoparticles. It was found that cellular uptake changed with both size and surface physiochemical properties, and that PVP-IO-37 with a core size of 37 nm and hydrodynamic particle size of 100 nm exhibited higher cellular uptake rate and greater distribution than other PVP-IOs and Feridex. We systematically investigated the effect of nanoparticle size on MRI of normal liver and hepatic lesions in vivo. The physical and chemical properties of the nanoparticles influenced their pharmacokinetic behavior, which ultimately determined their ability to accumulate in the liver. The contrast enhancement of PVP-IOs within the liver was highly dependent on the overall size of the nanoparticles, and the 100 nm PVP-IO-37 nanoparticles exhibited the greatest enhancement. These results will have implications in designing engineered nanoparticles that are optimized as MR contrast agents or for use in therapeutics.

  2. INTERACTION OF POLYVINYLPYRROLIDONE WITH METAL CHLORIDE AQUEOUS SOLUTIONS

    Institute of Scientific and Technical Information of China (English)

    Mohammad Saleem Khan; Khaista Gul; Najeeb Ur Rehman

    2004-01-01

    Interactions of polyvinylpyrrolidone (PVP) with metal chlorides (MgCl2, CaCl2, KC1 and BaC12) have been investigated by viscometric and spectrophotometric techniques in aqueous solutions. Intrinsic viscosity [η] of (PVP) has shown a discontinuity with varying concentration of metal chlorides. The decreasing order of effectiveness of cation is K1+>Ca2+> Mg2+> Ba2+ for poly(vinylpyrrolidone) solution. Changes in the absorption spectra of the cosolutes were observed in the presence of PVP in the lower limit of the UV-visible region i.e. 200-210 nm. These changes were attributed to interaction of PVP molecules with the cosolute molecules. As the concentration of the cosolute increased, a red shift in the peaks was observed, indicating an increase in interaction between PVP and cosolutes.

  3. Radiation crosslinking of starch/water-soluble polymer blends for hydrogel

    Energy Technology Data Exchange (ETDEWEB)

    Hashim, K.; Mohid, N.; Bahari, K.; Dahlan, K.Z. [Radiation Processing Technology Division, Malaysian Institute Nuclear Technology Research Malaysia (MINT), Bangi, 43000 Kajang (Malaysia)

    2000-03-01

    Water-soluble polymers such as PVP(polyvinyl pyrrolidone) and PVA(polyvinyl alcohol), in aqueous solution can form hydrogel easily upon gamma or electron beam irradiation. The properties of hydrogels, particularly for wound dressing application, can be further improved by adding sago starch to the blend. Results show improved gel strength and elongation properties of the hydrogel with increasing sago concentration. It was found that the PVA/sago hydrogel gives better gel strength and elongation than the PVP/sago hydrogel. The tackiness property of the PVA/sago hydrogel increased with increase amount of sago starch added. In case of PVP/sago hydrogel, the tackiness property shows significant increase with increasing amount of sago except for the 5%PVP composition. The swelling properties of PVP/sago and PVA/sago hydrogel decreased with increasing amount of sago but the crosslink density of the hydrogels also reduced. (author)

  4. Preparation of poly(N-vinylpyrrolidone-stabilized ZnO colloid nanoparticles

    Directory of Open Access Journals (Sweden)

    Tatyana Gutul

    2014-04-01

    Full Text Available We propose a method for the synthesis of a colloidal ZnO solution with poly(N-vinylpyrrolidone (PVP as stabilizer. Stable colloidal solutions with good luminescence properties are obtained by using PVP as stabilizer in the synthesis of ZnO nanoparticles by a sol–gel method assisted by ultrasound. Nanoparticles with sizes of 30–40 nm in a PVP matrix are produced as a solid product. The colloidal ZnO/PVP/methanol solution, apart from the most intense PL band at 356 nm coming from the PVP, exhibits a strong PL band at 376 nm (3.30 eV which corresponds to the emission of the free exciton recombination in ZnO nanoparticles.

  5. Preparation of MoS₂-polyvinylpyrrolidone nanocomposites for flexible nonvolatile rewritable memory devices with reduced graphene oxide electrodes.

    Science.gov (United States)

    Liu, Juqing; Zeng, Zhiyuan; Cao, Xiehong; Lu, Gang; Wang, Lian-Hui; Fan, Qu-Li; Huang, Wei; Zhang, Hua

    2012-11-19

    A facile method for exfoliation and dispersion of molybdenum disulfide (MoS2) with the aid of polyvinylpyrrolidone (PVP) is proposed. The resultant PVP-coated MoS2 nanosheets, i.e., MoS2-PVP nanocomposites, are well dispersed in the low-boiling ethanol solvent, facilitating their thin film preparation and the device fabrication by solution processing technique. As a proof of concept, a flexible memory diode with the configuration of reduced graphene oxide (rGO)/MoS2-PVP/Al exhibited a typical bistable electrical switching and nonvolatile rewritable memory effect with the function of flash. These experimental results prove that the electrical transition is due to the charge trapping and detrapping behavior of MoS2 in the PVP dielectric material. This study paves a way of employing two-dimensional nanomaterials as both functional materials and conducting electrodes for the future flexible data storage.

  6. Morphological control and optical properties of nanocrystalline ZnO powder from precipitation method

    Directory of Open Access Journals (Sweden)

    Sumetha Suwanboon

    2007-11-01

    Full Text Available Nanocrystalline ZnO powders have been synthesized by using zinc acetate dihydrate and PVP as starting materials. The calcined powders in air at 600oC for 1 hour have been characterized by XRD, indexing the wurtzite or hexagonal structure with the smallest crystallite size of ~ 44.76 nm, and lattice parameters a and c of 0.3249 and 0.5204 nm, respectively at 3x10-4 M PVP. The SEM images show that the morphology has been changed from plate-like to small rod shape when adding PVP to solutions and the morphology has tended to be monosized at higher PVP concentration. The smallest grain sizes of ZnO powders are ~ 130 nm at 3x10-4 M PVP. The optical band gap of all ZnO powders in this study varied between 3.218-3.229 eV.

  7. [Study on Xinyueshu spray drying assisted with copovidone and its effect on powder property].

    Science.gov (United States)

    Jiang, Yan-Rong; Zhang, Zhen-Hai; Ding, Dong-Mei; Yan, Hong-Mei; Hu, Shao-Ying; Jia, Xiao-Bin

    2013-12-01

    To study the application characteristics of copovidone (PVP-S630) in Xinyueshu extracts during the spray drying process, and its effect on such pharmaceutical properties as micromeritics and drug release behavior. PVP-S630 was added into Xinyueshu extracts to study on the spray drying, the effect of different dosages of PVP-S630 against the wall sticking effect of the spray drying, as well as the power property of Xinyueshu spray drying power and the dissolution in vitro behavior of the effective component of hyperoside. The results showed that PVP-S630 revealed a significant anti-wall sticking effect, with no notable change in the grain size of the spray drying power, increase in the fluidity, improvement in the moisture absorption and remarkable rise in the dissolution in vitro behavior of hyperoside. It was worth further studying the application of PVP-S630 in spray drying power of traditional Chinese medicine.

  8. Preliminary results in surgery of Parkinson's disease.

    Science.gov (United States)

    Nasser, J A; Confort, C I; Ferraz, A; Bouza, A A

    1998-09-01

    The authors present the preliminary results of 20 patients selected to be operated on between January 1996 and April 1997. These patients presented one of the present indications for stereotactic posteroventral pallidotomy (PVP), such as: rigidity, akinesia/bradykinesia, gait dysfunction, drug induced dyskinesias and tremor. Every patient of this protocol was evaluated by: UPDRS score, Schwab and England scale, Hoehn and Yahr Staging Scale before and after surgery. The results in 3 months showed a remarkable improvement after PVP (P < 0.01) in all functional assessments, except for facial expression, speech and posture. The morbidity was 5%. 5 patients (25%) who were in Hoehn and Yahr 5 underwent a bilateral simultaneous PVP. In 5 patients (25%), who had tremor, during the PVP, VIM thalamotomy was added. These preliminary results, suggest that PVP is highly effective for PD symptoms.

  9. Genistein Modified Polymer Blends for Hemodialysis Membranes

    Science.gov (United States)

    Chang, Teng; Kyu, Thein; Define, Linda; Alexander, Thomas

    2012-02-01

    A soybean-derived phytochemical called genistein was used as a modifying agent to polyether sulfone/polyvinyl pyrrolidone (PES/PVP) blends to produce multi-functional hemodialysis membranes. With the aid of phase diagrams of PES/PVP/genistein blends, asymmetric porous membranes were fabricated by coagulating in non-solvent. Both unmodified and genistein modified PES/PVP membranes were shown to be non-cytotoxic to the blood cells. Unmodified PES/PVP membranes were found to reduce reactive oxygen species (ROS) levels, whereas the genistein modified membranes exhibited suppression for ˜60% of the ROS levels. Also, the genistein modified membranes revealed significant suppression of pro-inflammatory cytokines: IL-1β, IL-6, and TNF-α. Moreover, addition of PVP to PES showed the reduced trend of platelet adhesion and then leveled off. However, the modified membranes exhibited suppression of platelet adhesion at low genistein loading, but beyond 15 wt%, the platelet adhesion level rised up.

  10. Pain reduction after percutaneous vertebroplasty for myeloma-associated vertebral fractures

    DEFF Research Database (Denmark)

    Simony, Ane; Hansen, Emil Jesper; Gaurilcikas, Marius

    2014-01-01

    INTRODUCTION: Percutaneous vertebroplasty (PVP) is a minimally invasive procedure with cement augmentation of vertebral fractures. It was introduced in 1987 as a treatment for painful haemangiomas and is today mostly used for painful osteoporotic fractures of the spine. Two randomised, double......-blinded trials published in 2009 have raised a debate about the efficiency of the PVP treatment. The aim of this study was to assess the safety and efficacy of PVP for vertebral body fractures in myeloma patients. METHODS: A consecutive group of patients with multiple myeloma who underwent PVP were reviewed......: PVP is a safe and efficient procedure in the treatment of painful vertebral fractures in patients with multiple myeloma. The main advantages are the immediate stabilisation of the fractured vertebral body, reduction of the pain level and the fact that the patient can be discharged after two hours...

  11. Formulation and characterisation of tetracycline-containing bioadhesive polymer networks designed for the treatment of periodontal disease.

    Science.gov (United States)

    Jones, David S; Lawlor, Michelle S; Woolfson, A David

    2004-01-01

    This study described the drug release, rheological (dynamic and flow) and textural/mechanical properties of a series of formulations composed of 15% w/w polymethylvinylether-co-maleic anhydride (PMVE-MA), 0-9% w/w polyvinylpyrrolidone (PVP) and containing 1-5% w/w tetracycline hydrochloride, designed for the treatment of periodontal disease. All formulations exhibited pseudoplastic flow with minimal thixotropy. Increasing the concentration of PVP sequentially increased the zero-rate viscosity (derived from the Cross model) and the hardness and compressibility of the formulations (derived from texture profile analysis). These affects may be accredited to increased polymer entanglement and, in light of the observed synergy between the two polymers with respect to their textural and rheological properties, interaction between PVP and PMVE-MA. Increasing the concentration of PVP increased the storage and loss moduli yet decreased the loss tangent of all formulations, indicative of increased elastic behaviour. Synergy between the two polymers with respect to their viscoelastic properties was observed. Increased adhesiveness, associated with increased concentrations of PVP was ascribed to the increasing bioadhesion and tack of the formulations. The effect of increasing drug concentration on the rheological and textural properties was dependent on PVP concentration. At lower concentrations (0, 3% w/w) no effect was observed whereas, in the presence of 9% w/w PVP, increasing drug concentration increased formulation elasticity, zero rate viscosity, hardness and compressibility. These observations were ascribed to the greater mass of suspended drug in formulations containing the highest concentration of PVP. Drug release from formulations containing 6 and 9% PVP (and 5% w/w drug) was prolonged and swelling/diffusion controlled. Based on the drug release, rheological and textural properties, it is suggested that the formulation containing 15% w/w PMVE-MA, 6% w/w PVP and

  12. Electrospinning fabrication and characterization of magnetic-upconversion fluorescent bifunctional core-shell nanofibers

    Science.gov (United States)

    Ma, Qianli; Wang, Jinxian; Dong, Xiangting; Yu, Wensheng; Liu, Guixia

    2014-02-01

    Novel magnetic-upconversion fluorescent bifunctional core-shell nanofibers have been successfully fabricated by coaxial electrospinning technology. NaYF4:Yb3+,Er3+ and Fe3O4 nanoparticles (Nps) were incorporated into polyvinylpyrrolidone (PVP) and electrospun into core-shell nanofibers with Fe3O4/PVP as core and NaYF4:Yb3+,Er3+/PVP as the shell. The morphology and properties of the final products were investigated in detail by X-ray diffractometry, scanning electron microscopy, transmission electron microscopy, vibrating sample magnetometer, and fluorescence spectroscopy. The core contained magnetic Nps was ca. 100 nm in diameter, and the shell scattered with NaYF4:Yb3+, Er3+ Nps was ca. 80 nm in thickness. Fluorescence emission peaks of Er3+ in the [Fe3O4/PVP]@[NaYF4:Yb3+,Er3+/PVP] core-shell nanofibers were observed. Compared with Fe3O4/NaYF4:Yb3+,Er3+/PVP composite nanofibers, the luminescent intensity of the [Fe3O4/PVP]@[NaYF4:Yb3+,Er3+/PVP] core-shell nanofibers was much higher, because the Fe3O4 Nps were only distributed in the core of the core-shell nanofibers, thus the manufactured core-shell nanofibers possessed excellent magnetic properties. The new type magnetic-upconversion fluorescent bifunctional [Fe3O4/PVP]@[NaYF4:Yb3+,Er3+/PVP] core-shell nanofibers have many potential applications in display device, nanorobots, protein determination, and target delivery of drug owing to their excellent magnetism and fluorescence.

  13. Taurolidine and povidone-iodine induce different types of cell death in malignant pleural mesothelioma.

    Science.gov (United States)

    Opitz, I; Sigrist, B; Hillinger, S; Lardinois, D; Stahel, R; Weder, W; Hopkins-Donaldson, S

    2007-06-01

    Taurolidine and povidone-iodine (PVP-I) are used in every day clinical practice, taurolidine as a broad spectrum antibiotic, and PVP-I as an antiseptic. The type of cell death induced in malignant pleural mesothelioma (MPM) cell lines by these agents was compared, and their ability to sensitize to chemotherapy assessed. Both taurolidine and PVP-I inhibited MPM cell growth after 7.5min incubation, but taurolidine was more effective at later time points and was more specific towards tumour cells than PVP-I. Taurolidine induced death by caspase-dependent and independent mechanisms, whereas in contrast, PVP-I induced a necrotic phenotype that was not caspase-dependent. Interestingly, both taurolidine and PVP-I induced the production of reactive oxygen intermediates and decreased mitochondrial membrane permeability, and cell death was inhibited by the oxygen scavenger N-acetyl cysteine. Taurolidine but not PVP-I treatment resulted in p53 activation in 2/3 MPM cell lines and a decrease in the protein levels of survivin, Bcl-2 and Mcl-1. Survivin also decreased in response to PVP-I whereas Bcl-xL remained unaffected by both treatments. Targeting of Bcl-xL with siRNA sensitized MPM cells to taurolidine and taurolidine treatment sensitized MPM cells to cisplatin-induced apoptosis. In conclusion, taurolidine and PVP-I are both cytotoxic to human MPM cells at early and late time points and induce reactive oxygen intermediate production. Taurolidine induces apoptosis and necrosis, activates p53 and sensitizes cells to cisplatin, whereas PVP-I inhibits cell growth via necrosis. Both agents are promising candidates for use in local treatment within multimodality concepts for MPM.

  14. Monodisperse polyvinylpyrrolidone-coated CoFe{sub 2}O{sub 4} nanoparticles: Synthesis, characterization and cytotoxicity study

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Guangshuo, E-mail: wgs8136@163.com; Ma, Yingying, E-mail: bzhjgcmyy@163.com; Mu, Jingbo; Zhang, Zhixiao; Zhang, Xiaoliang; Zhang, Lina; Che, Hongwei; Bai, Yongmei; Hou, Junxian; Xie, Hailong

    2016-03-01

    Graphical abstract: - Highlights: • Monodisperse cobalt ferrite (CoFe{sub 2}O{sub 4}) nanoparticles were prepared with various additions of polyvinylpyrrolidone (PVP) by a facile sonochemical method. • PVP-coated CoFe{sub 2}O{sub 4} showed relatively well dispersion and homogeneous shape with narrow size distribution. • PVP-coated CoFe{sub 2}O{sub 4} exhibited superparamagnetism with moderate saturation magnetization and hydrophilic character at room temperature. • Negligible cytotoxicity of PVP-coated CoFe{sub 2}O{sub 4} was observed even at high sample concentration after 24 h treatment. - Abstract: In this study, monodisperse cobalt ferrite (CoFe{sub 2}O{sub 4}) nanoparticles were prepared successfully with various additions of polyvinylpyrrolidone (PVP) by sonochemical method, in which PVP served as a stabilizer and dispersant. The effects and roles of PVP on the morphology, microstructure and magnetic properties of the obtained CoFe{sub 2}O{sub 4} were investigated in detail by X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and superconducting quantum interference device (SQUID). It was found that PVP-coated CoFe{sub 2}O{sub 4} showed relatively well dispersion with narrow size distribution. The field-dependent magnetization curves indicated superparamagnetic behavior of PVP-coated CoFe{sub 2}O{sub 4} with moderate saturation magnetization and hydrophilic character at room temperature. More importantly, the in vitro cytotoxicity testing exhibited negligible cytotoxicity of as-prepared PVP-CoFe{sub 2}O{sub 4} even at the concentration as high as 150 μg/mL after 24 h treatment. Considering the superparamagnetic properties, hydrophilic character and negligible cytotoxicity, the monodisperse CoFe{sub 2}O{sub 4} nanoparticles hold great potential in a variety of biomedical applications.

  15. Molecular dynamics simulation of amorphous indomethacin-poly(vinylpyrrolidone) glasses: solubility and hydrogen bonding interactions.

    Science.gov (United States)

    Xiang, Tian-Xiang; Anderson, Bradley D

    2013-03-01

    Amorphous drug dispersions are frequently employed to enhance solubility and dissolution of poorly water-soluble drugs and thereby increase their oral bioavailability. Because these systems are metastable, phase separation of the amorphous components and subsequent drug crystallization may occur during storage. Computational methods to determine the likelihood of these events would be very valuable, if their reliability could be validated. This study investigates amorphous systems of indomethacin (IMC) in poly(vinylpyrrolidone) (PVP) and their molecular interactions by means of molecular dynamics (MD) simulations. IMC and PVP molecules were constructed using X-ray diffraction data, and force-field parameters were assigned by analogy with similar groups in Amber-ff03. Five assemblies varying in PVP and IMC composition were equilibrated in their molten states then cooled at a rate of 0.03 K/ps to generate amorphous glasses. Prolonged aging dynamic runs (100 ns) at 298 K and 1 bar were then carried out, from which solubility parameters, the Flory-Huggins interaction parameter, and associated hydrogen bonding properties were obtained. Calculated glass transition temperature (T(g)) values were higher than experimental results because of the faster cooling rates in MD simulations. Molecular mobility as characterized by atomic fluctuations was substantially reduced below the T(g) with IMC-PVP systems exhibiting lower mobilities than that found in amorphous IMC, consistent with the antiplasticizing effect of PVP. The number of IMC-IMC hydrogen bonds (HBs) formed per IMC molecule was substantially lower in IMC-PVP mixtures, particularly the fractions of IMC molecules involved in two or three HBs with other IMC molecules that may be potential precursors for crystal growth. The loss of HBs between IMC molecules in the presence of PVP was largely compensated for by the formation of IMC-PVP HBs. The difference (6.5 MPa(1/2)) between the solubility parameters in amorphous IMC

  16. General in vitro method to analyze the interactions of synthetic polymers with human antibody repertoires.

    Science.gov (United States)

    Soshee, Anandakumar; Zürcher, Stefan; Spencer, Nicholas D; Halperin, Avraham; Nizak, Clément

    2014-01-13

    Recent reports on the hitherto underestimated antigenicity of poly(ethylene glycol) (PEG), which is widely used for pharmaceutical applications, highlight the need for efficient testing of polymer antigenicity and for a better understanding of its molecular origins. With this goal in mind, we have used the phage-display technique to screen large, recombinant antibody repertoires of human origin in vitro for antibodies that bind poly(vinylpyrrolidone) (PVP). PVP is a neutral synthetic polymer of industrial and clinical interest that is also a well-known model antigen in animal studies, thus allowing the comparison of in vitro and in vivo responses. We have identified 44 distinct antibodies that bind specifically to PVP. Competitive binding assays show that the PVP-antibody binding constant is proportional to the polymerization degree of PVP and that specific binding is detected down to the vinylpyrrolidone (VP) monomer level. Statistical analysis of anti-PVP antibody sequences identifies an amino-acid motif that is shared by many phage-display-selected anti-PVP antibodies that are similar to a previously described natural anti-PVP antibody. This suggests a role for this motif in specific antibody/PVP interactions. Interestingly, sequence analysis also suggests that only a single antibody chain containing this shared motif is responsible for antibody binding to PVP, as confirmed upon systematic deletion of either antibody chain for 90% of selected anti-PVP antibodies. Overall, a large number of antibodies in the human repertoires we have screened bind specifically to PVP through a small number of shared amino acid motifs, and preliminary comparison points to significant correlations between the sequences of phage-display-selected anti-PVP antibodies and their natural counterparts isolated from immunized mice in previous studies. This study pioneers the use of antibody phage-display to explore the antigenicity of biotechnologically relevant polymers. It also paves the

  17. Safety and Efficacy Studies of Vertebroplasty, Kyphoplasty, and Mesh-Container-Plasty for the Treatment of Vertebral Compression Fractures: Preliminary Report.

    Science.gov (United States)

    Chen, Chen; Li, Donghua; Wang, Zhiguo; Li, Tong; Liu, Xunwei; Zhong, Jian

    2016-01-01

    To evaluate the clinical safety and efficacies of percutaneous vertebroplasty (PVP), percutaneous kyphoplasty (PKP), and percutaneous mesh-container-plasty (PMCP) for the treatment of vertebral compression fractures (VCFs), a retrospective study of 90 patients with VCFs who had been treated by PVP (n = 30), PKP (n = 30), and PMCP (n = 30) was conducted. The clinical efficacies of these three treatments were evaluated by comparing their PMMA cement leakages, cement patterns, height restoration percentages, wedge angles, visual analogue scales (VAS), and oswestry disability index (ODI) at the pre- and post-operative time points. 6.67%, 3.33%, and 0% of patients had PMMA leakage in PVP, PKP, and PMCP groups, respectively. Three (solid, trabecular, and mixed patterns), two (solid and mixed patterns), and one (mixed patterns) types of cement patterns were observed in PVP, PKP, and PMCP groups, respectively. PKP and PMCP treatments had better height restoration ability than PVP treatment. PVP, PKP, and PMCP treatments had significant and similar ability in pain relief and functional recovery ability for the treatment of VCFs. These results indicate minimally invasive techniques were effective methods for the treatment of VCFs. Moreover, these initial outcomes suggest PMCP treatment may be better than both PVP treatment and PKP treatment.

  18. Effect of Polyvinylpyrrolidone on the Morphologies of Latex Films and Air Permeability of the Latex Finished Fabrics

    Institute of Scientific and Technical Information of China (English)

    SHEN Yi-feng; YE Jia-jia; YANG Lei; WU Ming-hua; NI Tian-xiang

    2010-01-01

    Low air permeability is a common problem happening to the coating finished and pigment dyed fabrics.To tackle the problem,styrene and butyl acrylate copolymer latex was prepared and used as substitute for the binder.Then,polyvinylpyrrolidoue(PVP)was fed into the latex.It was expected that pores could form in the resulting latex film after being rinsed.The morphologies of the latex films were analysized by scanning electric microscope(SEM).It was found that the continuity of the latex films decreased greatly because of the addition of PVP,leading to the loss of the stress at break of the films.After rinsing with methanol aqueous solution,PVP was easily leached off and(macro)void was formed in the latex films.The size of the void decreased with the increase of the PVP concentration.Then,the latex with and without PVP was used to finish the cotton fabrics and engaged as binder in pigment dyeing.After PVP was rinsed out,the air permeability of the fabrics improved greatly,which recovered to that of the unfinished one.In the meantime,the color fastness to rubbing was little affected.So,the method of PVP addition could be termed as an efficient way to improve the air permeability in coating and dyeing industry.

  19. Size control of semimetal bismuth nanoparticles and the UV-visible and IR absorption spectra.

    Science.gov (United States)

    Wang, Y W; Hong, Byung Hee; Kim, Kwang S

    2005-04-21

    We introduced a simple chemical method to synthesize semimetal bismuth nanoparticles in N,N-dimethylformamide (DMF) by reducing Bi(3+) with sodium borohydride (NaBH(4)) in the presence of poly(vinylpyrroldone) (PVP) at room temperature. The size and dispersibility of Bi nanoparticles can be easily controlled by changing the synthetic conditions such as the molar ratio of PVP to BiCl(3) and the concentration of BiCl(3). The UV-visible absorption spectra of Bi nanoparticles of different diameters are systematically studied. The surface plasmon peaks broaden with the increasing molar ratio of PVP to BiCl(3) as the size of bismuth nanoparticles decreases. Infrared (IR) spectra of the complexes with different molar ratios of PVP/BiCl(3) show a strong interaction between the carboxyl oxygen (C=O) of PVP and Bi(3+) ion and a weak interaction between the carboxyl oxygen (C=O) of PVP and the Bi atom in nanoparticles. This indicates that PVP serves as an effective capping ligand, which prevents the nanoparticles from aggregation.

  20. Nanocomposite scaffold with enhanced stability by hydrogen bonds between collagen, polyvinyl pyrrolidone and titanium dioxide.

    Science.gov (United States)

    Li, Na; Fan, Xialian; Tang, Keyong; Zheng, Xuejing; Liu, Jie; Wang, Baoshi

    2016-04-01

    In this study, three-dimensional (3D) nanocomposite scaffolds, as potential substrates for skin tissue engineering, were fabricated by freeze drying the mixture of type I collagen extracted from porcine skin and polyvinyl pyrrolidone (PVP)-coated titanium dioxide (TiO2) nanoparticles. This procedure was performed without any cross-linker or toxic reagents to generate porosity in the scaffold. Both morphology and thermal stability of the nanocomposite scaffold were examined. The swelling behavior, mechanical properties and hydrolytic degradation of the composite scaffolds were carefully investigated. Our results revealed that collagen, PVP and TiO2 are bonded together by four main hydrogen bonds, which is an essential action for the formation of nanocomposite scaffold. Using Coasts-Redfern model, we were able to calculate the thermal degradation apparent activation energy and demonstrated that the thermal stability of nanocomposites is dependent on amount of PVP incorporated. Furthermore, SEM images showed that the collagen fibers are wrapped and stabilized on scaffolds by PVP molecules, which improve the ultimate tensile strength (UTS). The UTS of PVP-contained scaffold is four times higher than that of scaffold without PVP, whereas ultimate percentage of elongation (UPE) is decreased, and PVP can enhance the degradation resistance.

  1. High-refractive Index Nanocomposite Films Of Polyvinyl-pyrolidone And CdS Nanoparticles By In-Situ Thermolysis

    Science.gov (United States)

    Chaudhuri, Tapas K.; Patel, Mitesh G.

    2010-12-01

    A simple and rapid process for deposition of high refractive index films of CdS/PVP nanocomposite is described. CdS/PVP films are prepared on glass substrate by dip coating a precursor film from methanolic solution of thio-organic complex of cadmium and PVP and subsequent heating at 180° C in air for 10 min. The transmission spectra of the films (thickness ˜700 nm) in the wavelength range 300 to 1000 nm showed an absorption edge near 500 nm due to CdS and high transmission of 85% beyond 500 nm. The refractive index is found to be 1.74 by Swanepoel method, which is between that of PVP (1.48) and CdS (2.5). Transmission Electron Microscopy showed that PVP matrix contains 5 to 10 nm CdS nanocrystals. X-ray and electron diffraction revealed the formation of cubic CdS nanoparticles in PVP. Fourier Transform Infrared spectroscopy of the composite showed that there is a strong interaction between CdS nanocrystals and PVP.

  2. Aligned Electrospun Polyvinyl Pyrrolidone/Poly ɛ-Caprolactone Blend Nanofiber Mats for Tissue Engineering

    Science.gov (United States)

    Charernsriwilaiwat, Natthan; Rojanarata, Theerasak; Ngawhirunpat, Tanasait; Opanasopit, Praneet

    2016-02-01

    Electrospun nanofibrous materials are widely used in medical applications such as tissue engineering scaffolds, wound dressing material and drug delivery carriers. For tissue engineering scaffolds, the structure of the nanofiber is similar to extracellular matrix (ECM) which promotes the cell growth and proliferation. In the present study, the aligned nanofiber mats of polyvinyl pyrrolidone (PVP) blended poly ɛ-caprolactone (PCL) was successfully generated using electrospinning technique. The morphology of PVP/PCL nanofiber mats were characterized by scanning electron microspore (SEM). The chemical and crystalline structure of PVP/PCL nanofiber mats were analyzed using Fourier transform infrared spectroscopy (FTIR) and powder X-ray diffactometer (PXRD). The water contact angle of mats was investigated. Cell culture studies using normal human fibroblasts (NHF) were performed to assess cell morphology, cell alignment and cell proliferation. The results indicated that the fiber were in nanometer range. The PVP/PCL was well dispersed in nanofiber mats and was in amorphous form. The water contact angle of PVP/PCL nanofiber mats was lower than PCL nanofiber mats. The PVP/PCL nanofiber mats exhibited good biocompatibility with NHF cells. In summary, the PVP/PCL nanofiber mats had potential to be used in tissue engineering and regenerative medicine.

  3. Nano-porous ultra-high specific surface ultrafine fibers

    Institute of Scientific and Technical Information of China (English)

    LI Xinsong; NIE Guangyu

    2004-01-01

    Nano-porous ultra-high specific surface ultrafine fibers are created by the method of "electrospinning-phase separation-leaching" (EPL) for the first time. First of all, polymer solutions of polyacrylonitrile (PAN) and polyvinylpyrrolidone (PVP) blends dissolved in co-solvent are electrospun to make ultrafine fibers when charged to high voltages. The incompatibility of PAN and PVP induces phase separation to form microdomains of PVP in the polymer blend ultrafine fibers. Then, PVP microdomains in the blend fibers are leached out in water, and porous PAN ultrafine fibers are obtained. Lastly, the surface and cross-section of the porous ultrafine fibers are observed in detail by field emission scanning electron microscope (FESEM), and the specific surface of the ultrafine fibers is measured by means of nitrogen absorption. With increasing the content of PVP, the specific surface area of the ultrafine fibers increases apparently. The specific surface area of the porous ultrafine fibers with the diameter of 2130 nm is more than 70 m2·g-1. The cross-section of the PAN porous ultrafine fibers after leaching of PVP microdomains from polymer blend fibers with the feed ratio of PAN/PVP of 10/20 shows the characteristic of porous structure with pore diameter of ca 30 nm according to FESEM photo.

  4. Rheological behaviour of irradiated wound dressing poly(vinyl pyrrolidone) hydrogels

    Science.gov (United States)

    Lugão, Ademar B.; Rogero, Sizue O.; Malmonge, Sônia M.

    2002-03-01

    The use of hydrogels as biomaterials has increased lately. Poly(vinyl pyrrolidone) (PVP) is an example of polymer hydrogels applied for the synthesis of hydrogel to be used in different biomedical applications. This paper describes a study on rheological properties of PVP hydrogels obtained by gamma radiation techniques. PVP hydrogels were obtained by gamma radiation of PVP water solutions with different radiation doses. It was studied the influence of additives such as poly(ethylene glycol) (PEG), poly(ethylene oxide) (PEO) and glycerol on the rheological behaviour of the gel. The rheological behaviour of hydrogel samples was characterized by measuring the shear storage modulus ( G') under dynamic shear loading. Besides this, sterility and cytotoxicity tests were performed. The study on rheological behaviour of hydrogels showed that G' of PVP gels change according to the additive used. Glycerol increases the fluidity of the gel. The influence of PEG depends on the amount and on its molecular mass. The increase on PEG amount and molecular mass cause a decrease of G' and an increase in the crosslinking density of PVP hydrogel network. The use of high molecular weight PEO allows the increase of the elasticity of the PVP gels.

  5. Safety and Efficacy Studies of Vertebroplasty, Kyphoplasty, and Mesh-Container-Plasty for the Treatment of Vertebral Compression Fractures: Preliminary Report

    Science.gov (United States)

    Chen, Chen; Li, Donghua; Wang, Zhiguo; Li, Tong; Liu, Xunwei; Zhong, Jian

    2016-01-01

    To evaluate the clinical safety and efficacies of percutaneous vertebroplasty (PVP), percutaneous kyphoplasty (PKP), and percutaneous mesh-container-plasty (PMCP) for the treatment of vertebral compression fractures (VCFs), a retrospective study of 90 patients with VCFs who had been treated by PVP (n = 30), PKP (n = 30), and PMCP (n = 30) was conducted. The clinical efficacies of these three treatments were evaluated by comparing their PMMA cement leakages, cement patterns, height restoration percentages, wedge angles, visual analogue scales (VAS), and oswestry disability index (ODI) at the pre- and post-operative time points. 6.67%, 3.33%, and 0% of patients had PMMA leakage in PVP, PKP, and PMCP groups, respectively. Three (solid, trabecular, and mixed patterns), two (solid and mixed patterns), and one (mixed patterns) types of cement patterns were observed in PVP, PKP, and PMCP groups, respectively. PKP and PMCP treatments had better height restoration ability than PVP treatment. PVP, PKP, and PMCP treatments had significant and similar ability in pain relief and functional recovery ability for the treatment of VCFs. These results indicate minimally invasive techniques were effective methods for the treatment of VCFs. Moreover, these initial outcomes suggest PMCP treatment may be better than both PVP treatment and PKP treatment. PMID:26963808

  6. Safety and Efficacy Studies of Vertebroplasty, Kyphoplasty, and Mesh-Container-Plasty for the Treatment of Vertebral Compression Fractures: Preliminary Report.

    Directory of Open Access Journals (Sweden)

    Chen Chen

    Full Text Available To evaluate the clinical safety and efficacies of percutaneous vertebroplasty (PVP, percutaneous kyphoplasty (PKP, and percutaneous mesh-container-plasty (PMCP for the treatment of vertebral compression fractures (VCFs, a retrospective study of 90 patients with VCFs who had been treated by PVP (n = 30, PKP (n = 30, and PMCP (n = 30 was conducted. The clinical efficacies of these three treatments were evaluated by comparing their PMMA cement leakages, cement patterns, height restoration percentages, wedge angles, visual analogue scales (VAS, and oswestry disability index (ODI at the pre- and post-operative time points. 6.67%, 3.33%, and 0% of patients had PMMA leakage in PVP, PKP, and PMCP groups, respectively. Three (solid, trabecular, and mixed patterns, two (solid and mixed patterns, and one (mixed patterns types of cement patterns were observed in PVP, PKP, and PMCP groups, respectively. PKP and PMCP treatments had better height restoration ability than PVP treatment. PVP, PKP, and PMCP treatments had significant and similar ability in pain relief and functional recovery ability for the treatment of VCFs. These results indicate minimally invasive techniques were effective methods for the treatment of VCFs. Moreover, these initial outcomes suggest PMCP treatment may be better than both PVP treatment and PKP treatment.

  7. Characterization of poly(4-vinylpyridine 1-oxide) by free-solution capillary electrophoresis and micellar electrokinetic chromatography.

    Science.gov (United States)

    Beneito-Cambra, Miriam; Herrero-Martínez, José M; Ramis-Ramos, Guillermo

    2008-08-01

    The migration characteristics of poly(4-vinylpyridine 1-oxide) (PVP-NO) in phosphate buffers of acidic pH (20 mM H3PO4 or NaH2PO4) have been studied using both free-solution capillary electrophoresis (FSCE) and MEKC. To inhibit adsorption, 250 mM o-phosphoethanolamine (2-aminoethyl dihydrogen phosphate) was used. In FSCE, PVP-NO showed a narrow peak and a broader band, both having anionic behavior. These peak and band were attributed to the free and aggregated or micellized PVP-NO forms, respectively. According to surface tension measurements, the CMC of SDS in the BGE was 1.8 and 0.48 mM in the absence and in the presence of 1000 microg/mL PVP-NO, respectively, and the association of the polymer with SDS was completed at 9.7 mM SDS. Using MEKC, a narrow peak and a broader band also appeared at SDS concentrations of ca. 1 mM, and their intensity increased with the SDS concentration. These peak and band were attributed to the formation of mixed micelles constituted by both free PVP-NO/SDS and aggregated PVP-NO/SDS, respectively. The determination of PVP-NO by FSCE in commercial additives for laundry was demonstrated.

  8. Inductive effect of poly(vinyl pyrrolidone) on morphology and photocatalytic performance of Bi2WO6

    Science.gov (United States)

    Zhang, Qiang; Chen, Jinxing; Xie, Yunyun; Wang, Mozhen; Ge, Xuewu

    2016-04-01

    Bi2WO6 has great potential applications in the field of photocatalyst due to its excellent visible-light photocatalytic performance. This work studied the detailed morphological evolution of Bi2WO6 particles synthesized in a simple hydrothermal system induced by the stabilizer poly(vinyl pyrrolidone) (PVP). The XRD and HRTEM results show PVP would not change the crystal structure of Bi2WO6, but the distribution of PVP on the initially formed Bi2WO6 nanosheets will induce the crystal growth, resulting in a distinct morphology evolution of Bi2WO6 with the increase of the concentration of PVP. At the same time, with the increase of the molecular weight of PVP, the morphology of Bi2WO6 varied from simple sheet-like (S-BWO) to some complicated morphology, such as flower-like (F-BWO), red blood cell-like (B-BWO), and square-pillar-like (SP-BWO). The photocatalytic performances of Bi2WO6 with various morphologies on the decomposition of RhB under visible light irradiation reveal that S-BWO has the best photocatalytic performance, while SP-BWO has the worst. This work not only gives the explanation of the inductive effect of PVP molecular chains on the morphological formation of Bi2WO6 particles, but also provides the controllable way to the preparation of Bi2WO6 with various morphologies taking advantage of the stabilizer PVP.

  9. Percutaneous Vertebroplasty Relieves Pain in Cervical Spine Metastases

    Science.gov (United States)

    Bao, Li; Jia, Pu; Li, Jinjun; Chen, Hao; Dong, Yipeng; Feng, Fei; Yang, He; Chen, Mengmeng

    2017-01-01

    Percutaneous vertebroplasty (PVP) has been shown to release spinal pain and stabilize the vertebral body. PVP is suggested as an alternative treatment in spinal metastasis. Although cervical metastases is less prevalent than thoracic and lumbar spine, PVP procedure in cervical vertebrae remains technical challenging. We retrospectively analyzed the data from patients (n = 9) who underwent PVP using anterolateral approach to treat severe neck pain and restricted cervical mobility from metastatic disease. Patients were rated using modified Tokuhashi score and Tomita score before the procedure. Visual analog scale (VAS), neck disability index (NDI), analgesic use, and imaging (X-ray or CT) were evaluated before PVP and 3 days, 3 months, and 6 months after PVP. All patients were in late stage of cancer evaluated using modified Tokuhashi and Tomita score. The cement leakage rate was 63.6% (14 of the 22 vertebrae) with no severe complications. VAS, NDI, and analgesic use were significantly decreased 3 days after the procedure and remained at low level until 6 months of follow-up. Our result suggested PVP effectively released the pain from patients with cervical metastasis. The results warrant further clinical investigation.

  10. The physical and chemical properties of the polyvinylalcohol/polyvinylpyrrolidone/hydroxyapatite composite hydrogel.

    Science.gov (United States)

    Ma, Yahui; Bai, Tongchun; Wang, Fei

    2016-02-01

    A hydrogel of polyvinylalcohol (PVA)/polyvinylpyrrolidone (PVP)/hydroxyapatite (HA) was prepared by a repeated freezing and thawing technique. The effect of HA on the hydrogel was evaluated by comparing the physical and chemical properties of PVA/PVP/HA and PVA/PVP hydrogels. By using theoretical models, the information about the swelling kinetics and the dehydration kinetics have been obtained. From the analysis of structure, mechanical properties, and molecular interaction, the application of PVA/PVP/HA hydrogel as a biomaterial has been evaluated. Relative to PVA/PVP, the PVA/PVP/HA hydrogel is of denser network structure, lower water content, larger storage modulus, and higher dehydration activation energy. These results reveal that, as HA fills in the hydrogel, the molecular interaction is enhanced, the free space of network is compressed, and the diffusion activation energy of water is increased. In spite of its water content being decreased, it is still in the range of meeting the requirement of bio-application. When the hydrogel is subjected to external forces, the matrix will transfer the load to the HA powder, thus enhance the strength of the hydrogel. For application in bio-materials, HA will still have osteoinductivity because its crystalline structure is not interrupted in PVA/PVP/HA hydrogel environment.

  11. Synthesis of iron nanoparticles with poly(1-vinylpyrrolidone-co-vinyl acetate) and its application to nitrate reduction

    DEFF Research Database (Denmark)

    Lee, Nara; Choi, Kyunghoon; Uthuppu, Basil

    2014-01-01

    This study aimed to synthesize dispersed and reactive nanoscale zero-valent iron (nZVI) with poly(1-vinylpyrrolidone-co-vinyl acetate) (PVP/VA), nontoxic and biodegradable stabilizer. The nZVI used for the experiments was prepared by reduction of ferric solution in the presence of PVP/VA with spe......This study aimed to synthesize dispersed and reactive nanoscale zero-valent iron (nZVI) with poly(1-vinylpyrrolidone-co-vinyl acetate) (PVP/VA), nontoxic and biodegradable stabilizer. The nZVI used for the experiments was prepared by reduction of ferric solution in the presence of PVP...... with increasing amount of PVP/VA (the ratios of 2). For the most stable nZVI coated by PVP/VA, its reactivity was examined by nitrate reduction in a closed batch system. The pseudo-first-order kinetic rate constants for the nitrate reduction by the nanoparticles with PVP/VA ratios of 0 and 2 were 0.1633 and 0...

  12. Low frequency dielectric relaxation processes and ionic conductivity of montmorillonite clay nanoparticles colloidal suspension in poly(vinyl pyrrolidone−ethylene glycol blends

    Directory of Open Access Journals (Sweden)

    2008-11-01

    Full Text Available The dielectric dispersion behaviour of montmorillonite (MMT clay nanoparticles colloidal suspension in poly(vinyl pyrrolidone-ethylene glycol (PVP-EG blends were investigated over the frequency range 20 Hz to 1 MHz at 30°C. The 0, 1, 2, 3, 5 and 10 wt% MMT clay concentration of the weight of total solute (MMT+PVP were prepared in PVP-EG blends using EG as solvent. The complex relative dielectric function, alternating current (ac electrical conductivity, electric modulus and impedance spectra of these materials show the relaxation processes corresponding to the micro-Brownian motion of PVP chain, ion conduction and electrode polarization phenomena. The real part of ac conductivity spectra of these materials obeys Jonscher power law σ′(ω =σdc + Aωn in upper frequency end of the measurement, whereas dispersion in lower frequency end confirms the presence of electrode polarization effect. It was observed that the increase of clay concentration in the PVP-EG blends significantly increases the ac conductivity values, and simultaneously reduces the ionic conductivity relaxation time and electric double layer relaxation time, which suggests that PVP segmental dynamics and ionic motion are strongly coupled. The intercalation of EG structures in clay galleries and exfoliation of clay sheets by adsorption of PVP-EG structures on clay surfaces are discussed by considering the hydrogen bonding interactions between the hydroxyl group (–OH of EG molecules, carbonyl group (C=O of PVP monomer units, and the hydroxylated aluminate surfaces of the MMT clay particles. Results suggest that the colloidal suspension of MMT clay nano particles in the PVP-EG blends provide a convenient way to obtain an electrolyte solution with tailored electrical conduction properties.

  13. A comparison of spray drying and milling in the production of amorphous dispersions of sulfathiazole/polyvinylpyrrolidone and sulfadimidine/polyvinylpyrrolidone.

    Science.gov (United States)

    Caron, Vincent; Tajber, Lidia; Corrigan, Owen I; Healy, Anne Marie

    2011-04-04

    Formulations containing amorphous active pharmaceutical ingredients (APIs) present great potential to overcome problems of limited bioavailability of poorly soluble APIs. In this paper, we directly compare for the first time spray drying and milling as methods to produce amorphous dispersions for two binary systems (poorly soluble API)/excipient: sulfathiazole (STZ)/polyvinylpyrrolidone (PVP) and sulfadimidine (SDM)/PVP. The coprocessed mixtures were characterized by powder X-ray diffraction (PXRD), differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR) and intrinsic dissolution tests. PXRD and DSC confirmed that homogeneous glassy solutions (mixture with a single glass transition) of STZ/PVP were obtained for 0.05 ≤ X(PVP) (PVP weight fraction) spray drying and for 0.6 ≤ X(PVP) spray drying and for 0.7 ≤ X(PVP) spray drying but not amorphous STZ could not be anticipated from the thermodynamic driving force of crystallization, but may be due to the lower molecular mobility of amorphous SDM compared to amorphous STZ. The solubility of the crystalline APIs in PVP was determined and the activities of the two APIs were fitted to the Flory-Huggins model. Comparable values of the Flory-Huggins interaction parameter (χ) were determined for the two systems (χ = -1.8 for SDM, χ = -1.5 for STZ) indicating that the two APIs have similar miscibility with PVP. Zones of stability and instability of the amorphous dispersions as a function of composition and temperature were obtained from the Flory-Huggins theory and the Gordon-Taylor equation and were found to be comparable for the two APIs. Intrinsic dissolution studies in aqueous media revealed that dissolution rates increased in the following order: physical mix of unprocessed materials spray dried systems.

  14. Comparison of percutaneous vertebroplasty and percutaneous kyphoplasty for the management of Kümmell's disease: A retrospective study

    Directory of Open Access Journals (Sweden)

    Guang-Quan Zhang

    2015-01-01

    Full Text Available Background: Post traumatic osteonecrosis of a vertebral body occurring in a delayed fashion was first described by the German doctor Kümmell in 1895. Several studies have reported percutaneous vertebroplasty (PVP, or percutaneous kyphoplasty (PKP for Kümmell's disease achieves good outcomes. However, it is unknown whether a technique is superior for the treatment of this disease. The objective of the study is to compare the efficacy of PVP and PKP for the treatment of Kümmell's disease. Materials and Methods: A retrospective review was conducted for 73 patients with Kümmell's disease. PVP was performed in 38 patients and PKP in 35 patients. Visual analogue score (VAS was used to evaluate pain. The anterior vertebral height was measured. The operative time, the incidence of cement leakage and the costs were recorded. Results: In both PVP group and PKP group, the VAS and anterior vertebral height significantly improved at 1-day postoperatively (P 0.05. Between the PVP and PKP groups, there were no significant differences in VAS and the anterior vertebral height at 1-day postoperatively and at the final followup (P > 0.05. The operating time and expense in the PKP group were higher than the PVP group (P < 0.001. Cement leakages in the PKP group were fewer than PVP group (P < 0.05. Conclusions: PVP is a faster, less expensive option that still provides a comparable pain relief and restoration of vertebral height to PKP for the treatment of Kümmell's disease. PKP has a significant advantage over PVP in term of the fewer cement leakages.

  15. Combined gene therapy of endostatin and interleukin 12 with polyvinylpyrrolidone induces a potent antitumor effect on hepatoma

    Institute of Scientific and Technical Information of China (English)

    Pei-Yuan Li; Ju-Sheng Lin; Zuo-Hua Feng; Yu-Fei He; He-Jun Zhou; Xin Ma; Xiao-Kun Cai; De-An Tian

    2004-01-01

    AIM: To study the antitumor effect of combined gene therapy of endostatin and interleukin 12 (IL-12) with polyvinylpyrrolidone (PVP) on mouse transplanted hepatoma.METHODS: Mouse endostatin eukaryotic plasmid (pSecES)with a mouse Igκ signal sequence inside and mouse IL-12 eukaryotic plasmid (pmIL-12) were transfected into BHK-21 cells respectively. Endostatin and IL-12 were assayed by ELISA from the supernant and used to culture endothelial cells and spleen lymphocytes individually. Proliferation of the latter was evaluated by MTT. H22 cells were inoculated into the leg musde of mouse, which was injected intratumorally with pSecES/PVP, pmIL-12/PVP or pSecES+pmIL-12/PVP repeatedly. Tumor weight, serum endostatin and serum IL-12 were assayed. Tumor infiltrating lymphocytes, tumor microvessel density and apoptosis of tumor cells were also displayed by HE staining, CD31 staining and TUNEL.RESULTS: Endostatin and IL-12 were secreted after transfection, which could inhibit the proliferation of endothelial cells or promote the proliferation of spleen lymphocytes.Tumor growth was highly inhibited by 91.8% after injection of pSecES+pmIL-12/PVP accompanied by higher serum endostatin and IL-12, more infiltrating lymphocytes, fewer tumor vessels and more apoptosis cells compared with injection of pSecES/PVP, pmIL-12/PVP or vector/PVP.CONCLUSION: Mouse endostatin gene and IL-12 gene can be expressed after intratumoral injection with PVP.Angiogenesis of hepatoma can be inhibited synergisticly,lymphocytes can be activated to infiltrate, and tumor cells are induced to apoptosis. Hepatoma can be highly inhibited or eradiated.

  16. EFFICACY OF MICROELECTRODE-GUIDED, POSTEROVENTRAL, UNILATERAL AND BILATERAL PALLIDOTOMY IN THE TREATMENT OF PARKINSON′S DISEASE

    Institute of Scientific and Technical Information of China (English)

    Eugene C. Lai, M.D; Joseph Jankovic, M.D; William G. Ondo, M.D; Joachim K. Krauss, M.D; Robert G. Grossman, M.D

    2000-01-01

    Objective: To investigate the short- and long-term efficacy of microelectrode-guided, posteroventral pallidotomy (PVP) in a large cohort of patients with advanced Parkinson's disease (PD). Background.: Advances in motor physiology, neuroimaging and neurosurgery have led to increased use of unilateral and bilateral PVP to treat patients with PD, particularly those with severe, medically intractable disease. Results from a prospective follow-up of a large series of patients are needed to establish the long-term efficacy and safety of PVP. Methods: We followed 101 consecutive patients who underwent PVP procedures performed at our center and returned for at least one post operative evaluation after 3 months. All had standardized clinical evaluations within 1 week before surgery and every 3 to 6 months after surgery. Data were collected during ′on′ and practically defined ′off periods for the Unified Parkinson′s Disease Rating Scale (UPDRS), Hoehn and Yahr stage, Schwab and England Activities of Daily Living (ADL) scale, and movement and reaction time. In addition, the severity and anatomic distribution of dyskinesia, neuropsychological status, average percent of ′on′ time with and without dyskinesia, and clinical global impression were assessed during a longitudinal follow-up. Results.: Eighty-nine patients (46 men) underwent unilateral PVP while 12 patients (6 men) had staged bilateral PVP. At 3 months after unilateral or staged bilateral PVP, 84 of the 101 patients reported marked or moderate improvement in their parkinsonian symptoms. Postoperative UPDRS mean total motor score improved in the 'off state by 35.5% and the mean ADL score by 33.7% (p<0.001). Rigidity, b radykinesia, and tremor scores also markedly improved after PVP, particularly on the contralateral side. Levodopa-induced dyskinesia was markedly reduced while daily 'on′ time increased by 34.5% (p<0.001). Seven patients had transient peri-operative complications including confusion

  17. Two P5CS genes from common bean exhibiting different tolerance to salt stress in transgenic Arabidopsis

    Indian Academy of Sciences (India)

    Ji Bao Chen; Jian Wei Yang; Zhao Yuan Zhang; Xiao Fan Feng; Shu Min Wang

    2013-12-01

    Many plants accumulate proline in response to salt stress. -pyrroline-5-carboxylate synthetase (P5CS) is the rate-limiting enzyme in proline biosynthesis in plants. Plasmid DNA (pCHF3-PvP5CS1 and pCHF3-PvP5CS2) containing the selectable neomycin phosphotransferase gene for kanamycin resistance and Phaseolus vulgaris P5CS (PvP5CS1 and PvP5CS2) cDNA was introduced into Arabidopsis plants using Agrobacterium-mediated gene transfer. Southern blot, northern blot and RT-PCR analyses demonstrated that the foreign genes were integrated into Arabidopsis chromosomal DNA and expressed. Single-gene transformants were analysed in this study. Transgenic plants expressed higher levels of PvP5CS1 and PvP5CS2 transcripts under salt stress conditions than under normal conditions. When treated with 0, 100 and 200 mM NaCl, the average proline content in leaves of transgenic plants was significantly higher $(P \\lt 0.01)$ than control plants. The average relative electrical conductivity (REC) of transgenic lines was significantly lower $(P \\lt 0.01)$ than control plants under salt stress condition. Biomass production of transgenic lines was significantly higher $(P \\lt 0.05)$ than control plants under 200 mM NaCl stress treatment. These results indicated that introducing PvP5CS1 and PvP5CS2 cDNA into transgenic Arabidopsis caused proline overproduction, increasing salt tolerance. Although the expression of PvP5CS1 in L4 lines and PvP5CS2 in S4 lines was the same under salt stress condition, the S4 lines accumulated 1.6 and 1.9 times more proline than the L4 lines under 100 and 200 mM NaCl treatments, respectively. The REC of S4 plants was 0.5 (100 mM NaCl) and 0.6 times (200 mM NaCl) that of L4 plants. The biomass production of S4 plants was 1.6 times (200 mM NaCl) more than in L4 plants. Total P5CS enzyme activity of S4 was significantly higher than that of L4. These results implied that the PvP5CS2 protein had stronger capacity to catalyze proline synthesis than PvP5CS1 under salt

  18. Synthesis of nanosized silver colloids by microwave dielectric heating

    Indian Academy of Sciences (India)

    Kirti Patel; Sudhir Kapoor; D P Dave; Tulsi Mukherjee

    2005-01-01

    Silver nanosized crystallites have been synthesized in aqueous and polyols viz., ethylene glycol and glycerol, using a microwave technique. Dispersions of colloidal silver have been prepared by the reduction of silver nitrate both in the presence and absence of stabilizer poly(vinylpyrolidone) (PVP). It was observed that PVP is capable of complexing and stabilizing Ag nanoparticles formed through the reduction of Ag+ ions in water and ethylene glycol. In the case of ethylene glycol, it has been shown that the use of PVP leads to particles with a high degree of stability. The colloids are stable in glycerol for months even in the absence of stabilizer.

  19. Characteristic time scales of coalescence of silver nanocomposite and nanoparticle films induced by continuous wave laser irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Paeng, Dongwoo; Grigoropoulos, Costas P., E-mail: cgrigoro@berkeley.edu [Department of Mechanical Engineering, University of California Berkeley, Berkeley, California 94720-1740 (United States); Lee, Daeho [Department of Mechanical Engineering, Gachon University, Seongnam-si, Gyeonggi-do 461-701 (Korea, Republic of)

    2014-08-18

    In-situ optical probing has been performed to analyze and compare the characteristic coalescence time scales of silver ion-doped polyvinylalcohol nanocomposite (Ag-PVA NC) and polyvinylpyrrolidone-capped silver nanoparticle (Ag-PVP NP) films subjected to continuous wave laser irradiation. The Ag-PVA NC yielded conductive metallic patterns by photothermal reduction of PVA, formation of nanoparticles from silver ions and their subsequent coalescence. On the other hand, Ag-PVP NP thin films produced conductive patterns through only coalescence of nanoparticles. Upon laser irradiation, Ag-PVA NC and Ag-PVP NP films exhibited different coalescence characteristics.

  20. Poly(4-vinylphenol gate insulator with cross-linking using a rapid low-power microwave induction heating scheme for organic thin-film-transistors

    Directory of Open Access Journals (Sweden)

    Ching-Lin Fan

    2016-03-01

    Full Text Available A Microwave-Induction Heating (MIH scheme is proposed for the poly(4-vinylphenol (PVP gate insulator cross-linking process to replace the traditional oven heating cross-linking process. The cross-linking time is significantly decreased from 1 h to 5 min by heating the metal below the PVP layer using microwave irradiation. The necessary microwave power was substantially reduced to about 50 W by decreasing the chamber pressure. The MIH scheme is a good candidate to replace traditional thermal heating for cross-linking of PVP as the gate insulator for organic thin-film-transistors.

  1. Investigation of Complexation of Linear Poly(N-vinyl-2-pyrrolidone with Poly(methacrylic acid-co-methyl methacrylate Gel

    Directory of Open Access Journals (Sweden)

    Guoqin Liu

    2011-01-01

    Full Text Available The contraction of poly(methacrylic acid-co-methyl methacrylate (P(MAA-co-MMA gel induced by complexation with linear poly(N-vinyl-2-pyrrolidone (PVP is quite different from that of poly(acrylic acid (PAA or poly(methacrylic acid (PMAA gel. It was found that the concentration of PVP has a strong effect on the complexation with P(MAA-co-MMA gel. When PVP was introduced into the P(MAA-co-MMA network, its dynamic mechanic properties vary greatly between complexed and uncomplexed networks. It had the following results: (1 the higher modulus ratio; (2 a slight contraction of gel.

  2. Computed tomography perfusion in living donor liver transplantation: an initial study of normal hemodynamic changes in liver grafts.

    Science.gov (United States)

    Zhuang, Zhi Guo; Qian, Li Jun; Wang, Bi Xiong; Zhou, Yan; Li, Qi Gen; Xu, Jian Rong; Cheng, Yu Fan

    2009-01-01

    Hepatic hemodynamic changes in grafts after living donor liver transplantation (LDLT) are complicated. In this study, computed tomography (CT) perfusion parameter values, especially portal vein perfusion (PVP), was retrospectively analyzed in recipients both with and without small-for-size syndrome (SFSS). PVP was significantly higher in non-SFSS recipients on post-operative day (POD) 14 or 28 than in normal donors before donation (p spleen size ratio and PVP on POD 14 in non-SFSS group (r = -0.545, p = 0.002). Furthermore, PVP in the SFSS group was significantly greater than in the non-SFSS group on POD 14 (p = 0.042). In conclusion, we successfully evaluated normal hemodynamic changes in grafts without SFSS by CT perfusion examination. To our knowledge, this is the first study on hemodynamic changes of living donor liver grafts using CT technique.

  3. Vertebroplasty in the treatment of back pain; Vertebroplastie zur Therapie des Rueckenschmerzes

    Energy Technology Data Exchange (ETDEWEB)

    Trumm, C.G.; Jakobs, T.F.; Zech, C.J.; Weber, C.; Reiser, M.F.; Hoffmann, R.T. [Klinikum Grosshadern der Ludwig-Maximilians-Universitaet, Institut fuer Klinische Radiologie, Muenchen (Germany)

    2006-06-15

    Percutaneous vertebroplasty (PVP) represents a minimally invasive option which is gaining in importance for the treatment of vertebral compression fractures (VCF) and osteolysis of the spine. This article describes the indications for its use, peri-interventional imaging, technique, and results of PVP. The current guidelines for performance of PVP are explained in accordance with the ''Interdisciplinary Consensus Paper on Vertebroplasty and Kyphoplasty'' of the German Professional Associations and the 2005 CIRSE Guidelines. The results of our own study carried out in 2002 are compared to the complication rates and clinical outcomes reported in the literature. Painful osteoporotic VCF and osteolysis within the vertebral body due to metastases and multiple myeloma are indications for PVP. Absolute contraindications are, in particular, asymptomatic VCF, alleviation of pain by drug treatment, therapy-refractory coagulopathies, allergies to cement components, and active infections. MRI or CT is indicated before undertaking PVP to assess the fracture age, to exclude other causes of pain, and to evaluate the posterior edge of the vertebral body. High-quality mono- or biplanar fluoroscopy - preferably in combination with CT (fluoroscopy) - is necessary for PVP to minimize the risk of cement leakage. A clear reduction in pain [mean reduction of 6.1 points (VAS)] is achieved in 86-92% of the patients with PVP. Our own study treating 58 patients (mean follow-up 323{+-}99 days) revealed a clear alleviation of pain in 77% [-5.7 points (VAS)]. PVP constitutes a safe and effective minimally invasive treatment approach to stabilize and reduce acute and chronic back pain due to osteoporotic VCF and tumor-associated osteolysis. (orig.) [German] Die perkutane Vertebroplastie (PVP) stellt bei osteoporotischen Wirbelkoerperfrakturen (WKF) und Osteolysen der Wirbelsaeule eine minimalinvasive Behandlungsmoeglichkeit dar, die zunehmend an Bedeutung gewinnt. In diesem

  4. Integrated antifouling and bactericidal polymer membranes through bioinspired polydopamine/poly(N-vinyl pyrrolidone) coating

    Science.gov (United States)

    Wang, Xianghong; Yuan, Shuaishuai; Shi, Dean; Yang, Yingkui; Jiang, Tao; Yan, Shunjie; Shi, Hengchong; Luan, Shifang; Yin, Jinghua

    2016-07-01

    Polypropylene (PP) non-woven has been widely used as wound dressing; however, the hydrophobic nature of PP can initiate bacterial attachment and subsequent biofilm formation. Herein, we propose a facile approach to functionalize PP non-woven with poly(ethylene glycol) (PEG) and poly(N-vinyl pyrrolidone)-iodine complex (PVP-I). PVP and PEG were successively tethered onto PP non-woven surface via versatile bioinspired dopamine (DA) chemistry, followed by complexing iodine with PVP moieties. It was demonstrated through the field emission scanning electron microscope (SEM) and spread plate method that the as-modified PP non-woven integrated both antifouling property of PEG for suppressing bacterial adhesion, and bactericidal property of PVP-I for killing the few adherent bacteria. Meanwhile, it could greatly resist platelet and red blood cell adhesion. The integrated antifouling and bactericidal PP non-woven surfaces might have great potential in various wound dressing applications.

  5. Investigation of nanocomposites made with poly(methacrylic acid-co-methyl methacrylate)/poly(N-vinyl-2-pyrrolidone)/multi-walled carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Guoqin, Liu; Wei, Miao [College of Material Science and Engineering, Henan University of Technology (China); Lin-Jian, Shangguan, E-mail: mikepolymer@126.com [School of Mechanical Engineering, North China University of Water Conservancy and Electric Power (China)

    2014-06-01

    Poly(methacrylic acid-co-methyl methacrylate) (P(MAA-co-MMA)) was prepared in the presence of poly(N-vinyl-2-pyrrolidone) (PVP) and multi-walled carbon nanotubes (MWNTs) via ultrasonic assisted solution free radical polymerization, i.e., P(MAA-co-MMA)/PVP/MWNTs nanocomposites. The morphology, glassy-state storage modulus, thermal behavior and swelling characteristics of P(MAA-co-MMA)/PVP/MWNTs nanocomposites were investigated. Scanning electron micrographs (SEM) revealed that MWNTs at low concentration could be uniformly dispersed into P(MAA-co-MMA)/PVP blends. With increasing MWNTs weight fraction, the average glassy-state modulus, glass transition temperatures and decomposition temperature of the nanocomposites increased, but their swelling characteristics decreased. (author)

  6. Poly(furfuryl alcohol) nanospheres: a facile synthesis approach based on confinement effect of polymer and a template for synthesis of metal oxide hollow nanospheres

    Indian Academy of Sciences (India)

    Wei-Zhi Wang; Zhi-Qiang Li; Kong-Lin Wu; Ya-Jing Lu; Ya-Fei Xu; Xin-Jie Song

    2015-12-01

    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 different morphologies of PFA could be obtained by adjusting the ratio of PVP and furfuryl alcohol (FA). As a whole, the results demonstrate that PVP plays a key role in controlling the polymerization process of FA. The confinement effect of PVP is proposed to explain the formation process of PFA nanospheres. Furthermore, the as-prepared PFA nanospheres have a functional surface that allow them to act as an ideal template for fabricating metal oxide hollow nanospheres.

  7. Transferring CdTe Nanoparticles from Liquid Phase to Polyvinylpyrrolidone Nanofibers by Electrospinning and Detecting Its Photoluminescence Property

    Institute of Scientific and Technical Information of China (English)

    WANG Shu-gang; YANG Qing-biao; BAI Jie; SONG Yan; ZHANG Chao-qun; LI Yao-xian

    2008-01-01

    The major aim of this work was to synthesize thio-stabilized CdTe nanoparticles(NPs) in an aqueous solution,which was then enwrapped with cetyltrimethylammonium bromide(CTAB),and finally transferred to the polyvinylpyrrolidone(PVP) matrix by electrospinning,The PVP nanofibers containing CdTe NPs were characterized by scanning electron microscopy(SEM) and transmission electron microscopy(TEM),to observe the morphology of the nanofibers and the distribution of CdTe NPs,The selective area electronic diffraction(SAED) pattern verified that CdTe NPs were cubic lattice,The photoluminescence(PL) spectrum indicated that CdTe NPs existed in an optical style in PVP nanofibers,Moreover,X-ray photoelectron spectra(XPS) revealed that thiol-stabilized CdTe NPs were enwrapped by CTAB,and PVP acted as a dispersant in the process of electrospinning.

  8. Fractional laser-assisted drug delivery

    DEFF Research Database (Denmark)

    Erlendsson, Andrés M; Doukas, Apostolos G; Farinelli, William A

    2016-01-01

    , potentially due to insufficient drug uptake in deeper skin layers. This study sought to investigate a standardized method to actively fill laser-generated channels by altering pressure, vacuum, and pressure (PVP), enquiring its effect on (i) relative filling of individual laser channels; (ii) cutaneous...... deposition and delivery kinetics; (iii) biodistribution and diffusion pattern, estimated by mathematical simulation. METHODS: Franz diffusion chambers (FCs) were used to evaluate the PVP-technique, comparing passive (AFXL) and active (AFXL + PVP) channel filling. A fractional CO2-laser generated superficial...... (225 µm;17.5 mJ/channel) and deep (1200 µm; 130.5 mJ/channel) channels, and PVP was delivered as a 3-minutes cycle of 1 minute pressure (+1.0 atm), 1 minute vacuum (-1.0 atm), and 1 minute pressure (+1.0 atm). Filling of laser channels was visualized with a colored biomarker liquid (n = 12 FCs, n = 588...

  9. Preliminary Study on the Removal of Steroidal Estrogens Using TiO2-Doped PVDF Ultrafiltration Membranes

    Directory of Open Access Journals (Sweden)

    Mingquan Wang

    2016-04-01

    Full Text Available Steroidal estrogens are a representative type of endocrine-disrupting chemical contaminant that has been detected in surface water. In this paper, modified polyvinylidene fluoride (PVDF membranes were prepared by adding different amounts of polyvinyl pyrrolidone (PVP and nano-TiO2 particles. PVDF-PVP membrane adsorption, UV photolysis and PVDF-PVP-TiO2 membrane photocatalysis performance were investigated by considering the rejection of estrone (E1 and 17β-estradiol (E2 in the cross-flow filtration experiments. The mechanism of photocatalytic degradation on TiO2-doped PVDF membranes was also evaluated. The results from the study indicated that adding PVP and nano-TiO2 appropriately in PVDF membranes could be an effective method for better E1and E2 rejection due to adsorption and photocatalytic degradation.

  10. Organic capping-Effect and mechanism in Mn-doped CdS nanocomposites

    Energy Technology Data Exchange (ETDEWEB)

    Verma, Prinsa, E-mail: prinsa.verma@gmail.co [Nanophosphor Application Center, Allahabad University (India); Satish Dhawan Space Center, ISRO (India); Manoj, Gali S. [Satish Dhawan Space Center, ISRO (India); Pandey, Avinash C. [Nanophosphor Application Center, Allahabad University (India)

    2010-03-01

    Driven with an objective of confining the growth of nanoparticles, polyvinyl pyrrolidone (PVP) was used as a capping agent over Mn{sup +2}-doped CdS nanoparticles. The mechanism is studied and results are discussed. An improvement in the doping efficiency and improvement in reproducibility of the nanoparticles as compared to the common co-precipitation method is observed which can be endorsed to the introduction of PVP, as coordination of PVP molecular orbitals with metallic orbitals attribute to the surface passivation of the CdS nanoparticles. PVP helps in stabilizing the nanoparticles, increases the doping efficiency and leads to enhancement in optoelectronic properties. A change in band gap is noticed as there is blue shift in wavelength compared to bulk due to confinement of particle size. The obtained nanoparticles are characterized by X-ray diffraction, transmission electron microscopy, ultraviolet-visible and photoluminescence spectroscopy.

  11. First experience of water pumping system in Yemen

    Energy Technology Data Exchange (ETDEWEB)

    Nyman, C. [Soleco Ltd., Borgaa (Finland)

    2000-07-01

    A photovoltaic water pump (PVP) was installed and monitored in a village at sea level in the east coast of Yemen. Economic study showed PVP to be competitive within the power range of small diesel pumps, where they often even constitute the least-cost option. Social study showed the high acceptance and better integration of PVP into the project village. The water in Yemen is found in wells at depths of 15 m down to 100 m, and more. The village population usually lives on the top of the steep mountains and the well is down in the valley. The first pilot PVP was installed in a village at sea level with an existing well. The work is supported by World Bank financing and a co-operation with a Danish and Finnish CTF of World Bank. (au)

  12. 76 FR 21701 - Plant Variety Protection Board; Open Meeting

    Science.gov (United States)

    2011-04-18

    ... the financial status of the PVP Office, ongoing business process reengineering project, E-business..., Beltsville, MD 20705. Telephone number (301) 504- 5518, fax (301) 504-5291, or e-mail: natalie.worku@ams.usda...

  13. Effects of oral exposure to silver nanoparticles on the sperm of rats.

    Science.gov (United States)

    Lafuente, D; Garcia, T; Blanco, J; Sánchez, D J; Sirvent, J J; Domingo, J L; Gómez, M

    2016-04-01

    It has been demonstrated that exposure to silver nanoparticles (AgNPs) can induce toxicological effects in rodents. In this study, we investigated whether sub-chronic oral exposure to different doses of polyvinil pyrrolidone (PVP)-coated AgNPs (PVP-AgNPs) (50, 100 and 200mg/kg/day) could induce harmful effects on epididymal sperm rat parameters. Sperm motility, viability and morphology were examined. Moreover, a histological evaluation of testis and epididymis was also performed. High doses of PVP-AgNPs showed higher sperm morphology abnormalities, while a progressive, but not significant effect, was observed in other sperm parameters. The current results suggest that oral sub-chronic exposure to PVP-AgNPs induces slight toxicological effects in sperm rat parameters.

  14. Effect of Added Poly (vinyl pyrrolidone) during Condensation on Properties of Poly(p-phenylene terephthalamide) Pulp

    Institute of Scientific and Technical Information of China (English)

    LI Jin-chun; YOU Xiu-lan; CAO Yu-tong; LIU Zhao-feng

    2009-01-01

    Poly (p-phenylene terephthalamide) (PPTA) pulp was prepared by polycondensation of the p-phenylene diamine (PPDA) with terephthaloyl chloride (TPC) in the completely anhydrous solvent system of N-methyl pyrrolidone (NMP) having calcium chloride, in the presence of poly (vinyl pyrrolidone) (PVP) having a viscosity average molecular weight lower than 40 000. It was confirmed that the polycondensation could be accelerated, the inherent viscosity of the polymer could be increased, and the polymers could be fibrillated more easily by the addition of the PVP. FTIR and X-ray spectra proved that PVP had not combined into molecular chains of the resultant PPTA pulps. The morphology of the resultant pulps, the effect of viscosity average molecular weight, amount and adding mode of PVP on inherent viscosity, specific surface area,and mean length of the resultant pulps were discussed in detail. And the friction and wear properties of the compound reinforced by the resultant pulps were simply investigated.

  15. Effects of video games on adolescents and adults.

    Science.gov (United States)

    Hart, Gordon M; Johnson, Bryan; Stamm, Brian; Angers, Nick; Robinson, Adam; Lally, Tara; Fagley, William H

    2009-02-01

    The present study compared a sample of American adolescents with a Spanish sample on a measure of video game addiction, the Problem Video Game Playing (PVP) survey developed in Spain. In addition, the study examined excessive video game playing and reported distress in social life, occupational activities, and school among high school students, college students, and adults. Samples taken from a large Eastern university, two suburban high schools, and an Internet survey were surveyed with an instrument developed by the authors and the PVP. Results show support for the PVP and a similarity between the Spanish and American samples but not for relationships between the PVP and assessments of distress in areas of daily functioning.

  16. Percutaneous vertebroplasty and kyphoplasty; Perkutane Vertebroplastie und Kyphoplastie

    Energy Technology Data Exchange (ETDEWEB)

    Wetzel, S.G. [Basel Univ. (Switzerland). Abt. fuer Neuroradiologie; Wilhelm, K.E. [Radiologische Universitaetsklinik Bonn (Germany)

    2006-09-15

    With percutaneous vertebroplasty, a minimal invasive method, bone cement is injected under radiological control into a vertebra. The technique was first applied for treatment of aggressive hemangiomas. Today, osteoporotic compression fractures and other vertebral pathologies that cause pain - foremost metastasis - are the main indications for PVP. Kyphoplasty (KP) is closely related to PVP; with this technique expandable balloons are introduced into a vertebra and the cavity is then filled with bone cement. Apart from pain treatment and stabilisation of the vertebra, the aim of the method is to restore and correct a local kyphosis. In this article the indications for both PVP and KP are discussed and the value of an interdisciplinary discussion that takes alternative therapeutic methods into account is stressed. Additionally, the technical aspects and the potential complications of the methods are explained. Finally, the therapeutic results of PVP and KP are reviewed in light of published results and our own experiences. (orig.)

  17. The influence of the polymer-stabilizer molecular weight on the spectral luminescence properties of composite sols and coatings containing PbS quantum dots

    Science.gov (United States)

    Evstrop'ev, K. S.; Dukel'skii, K. V.; Gatchin, Yu. A.; Evstrop'ev, S. K.; Bondarenko, I. B.

    2016-12-01

    The influence of the polyvinylpyrrolidone (PVP) molecular weight on the stability and spectral luminescence properties of sols of lead sulfide nanocrystals and the related composite coatings has been studied. It is shown that the spectral properties of PbS sols stabilized with low-molecular (PVP) and the related coatings are determined to a great extent by the formation of large particle aggregates in these materials and, accordingly, high level of light scattering. It is effective to use low-molecular PVP for preparing powder materials containing PbS quantum dots (QDs), because it allows one to perform fast powder precipitation and form small semiconductor particles. High-molecular PVP provides high aggregative and sedimentation stabilities of semiconductor nanocrystal sols. This polymer is effective for use in preparing stable QD sols and homogeneous coatings transparent in the visible spectral range.

  18. Distribution of binder in granules produced by means of twin screw granulation.

    Science.gov (United States)

    Fonteyne, Margot; Fussell, Andrew Luke; Vercruysse, Jurgen; Vervaet, Chris; Remon, Jean Paul; Strachan, Clare; Rades, Thomas; De Beer, Thomas

    2014-02-28

    According to the quality by design principle processes may not remain black-boxes and full process understanding is required. The granule size distribution of granules produced via twin screw granulation is often found to be bimodal. The aim of this study was to gain a better understanding of binder distribution within granules produced via twin screw granulation in order to investigate if an inhomogeneous spread of binder is causing this bimodal size distribution. Theophylline-lactose-polyvinylpyrrolidone K30 (PVP) (30-67.5-2.5%, w/w) was used as a model formulation. The intra-granular distribution of PVP was evaluated by means of hyperspectral coherent anti-Stokes Raman scattering (CARS) microscopy. For the evaluated formulation, no PVP rich zones were detected when applying a lateral spatial resolution of 0.5 μm, indicating that PVP is homogenously distributed within the granules.

  19. Influence of Polymer Molecular Weight on Drug-Polymer Solubility

    DEFF Research Database (Denmark)

    Knopp, Matthias Manne; Olesen, Niels Erik; Holm, Per

    2015-01-01

    In this study, the influence of polymer molecular weight on drug-polymer solubility was investigated using binary systems containing indomethacin (IMC) and polyvinylpyrrolidone (PVP) of different molecular weights. The experimental solubility in PVP, measured using a differential scanning...... calorimetry annealing method, was compared with the solubility calculated from the solubility of the drug in the liquid analogue N-vinylpyrrolidone (NVP). The experimental solubility of IMC in the low-molecular-weight PVP K12 was not significantly different from that in the higher molecular weight PVPs (K25......, K30, and K90). The calculated solubilities derived from the solubility in NVP (0.31-0.32 g/g) were found to be lower than those experimentally determined in PVP (0.38-0.40 g/g). Nevertheless, the similarity between the values indicates that the analogue solubility can provide valuable indications...

  20. Investigation of nanocomposites made with poly(methacrylic acid-co-methyl methacrylate/poly(N-vinyl-2-pyrrolidone/multi-walled carbon nanotubes

    Directory of Open Access Journals (Sweden)

    Liu Guoqin

    2014-01-01

    Full Text Available Poly(methacrylic acid-co-methyl methacrylate (P(MAA-co-MMA was prepared in the presence of poly(N-vinyl-2-pyrrolidone (PVP and multiwalled carbon nanotubes (MWNTs via ultrasonic assisted solution free radical polymerization, i.e., P(MAA-co-MMA/PVP/MWNTs nanocomposites. The morphology, glassy-state storage modulus, thermal behavior and swelling characteristics of P(MAA-co-MMA/PVP/MWNTs nanocomposites were investigated. Scanning electron micrographs (SEM revealed that MWNTs at low concentration could be uniformly dispersed into P(MAA-co-MMA/PVP blends. With increasing MWNTs weight fraction, the average glassy-state modulus, glass transition temperatures and decomposition temperature of the nanocomposites increased, but their swelling characteristics decreased.

  1. Multifunctional chitosan/polyvinyl pyrrolidone/45S5 Bioglass® scaffolds for MC3T3-E1 cell stimulation and drug release

    Energy Technology Data Exchange (ETDEWEB)

    Yao, Qingqing [Institute of Advanced Materials for Nano-Bio Applications, School of Ophthalmology & Optometry, Wenzhou Medical University, 270 Xueyuan Xi Road, Wenzhou, Zhejiang 325027 (China); Li, Wei [Institute of Biomaterials, Department of Materials Science and Engineering, University of Erlangen-Nuremberg, Cauerstrasse 6, Erlangen 91058 (Germany); Yu, Shanshan; Ma, Liwei [Institute of Advanced Materials for Nano-Bio Applications, School of Ophthalmology & Optometry, Wenzhou Medical University, 270 Xueyuan Xi Road, Wenzhou, Zhejiang 325027 (China); Jin, Dayong [Institute for Biomedical Materials and Devices, Faculty of Science, University of Technology Sydney, NSW 2007 (Australia); Advanced Cytometry Labs, ARC Center of Excellence for Nanoscale BioPhotonics, Macquarie University, Sydney, NSW 2109 (Australia); Boccaccini, Aldo R., E-mail: Aldo.Boccaccini@ww.uni-erlangen.de [Institute of Biomaterials, Department of Materials Science and Engineering, University of Erlangen-Nuremberg, Cauerstrasse 6, Erlangen 91058 (Germany); Liu, Yong, E-mail: yongliu1980@hotmail.com [Institute of Advanced Materials for Nano-Bio Applications, School of Ophthalmology & Optometry, Wenzhou Medical University, 270 Xueyuan Xi Road, Wenzhou, Zhejiang 325027 (China); Advanced Cytometry Labs, ARC Center of Excellence for Nanoscale BioPhotonics, Macquarie University, Sydney, NSW 2109 (Australia)

    2015-11-01

    Novel chitosan–polyvinyl pyrrolidone/45S5 Bioglass® (CS-PVP/BG) scaffolds were prepared via foam replication and chemical cross-linking techniques. The pristine BG, CS-PVP coated BG and genipin cross-linked CS-PVP/BG (G-CS-PVP/BG) scaffolds were synthesized and characterized in terms of chemical composition, physical structure and morphology respectively. Resistance to enzymatic degradation of the scaffold is improved significantly with the use of genipin cross-linked CS-PVP. The bio-effects of scaffolds on MC3T3-E1 osteoblast-like cells were evaluated by studying cell viability, adhesion and proliferation. The CCK-8 assay shows that cell viability on the resulting G-CS-PVP/BG scaffold is improved obviously after cross-linking of genipin. Cell skeleton images exhibit that well-stretched F-actin bundles are obtained on the G-CS-PVP/BG scaffold. SEM results present significant improvement on the cell adhesion and proliferation for cells cultured on the G-CS-PVP/BG scaffold. The drug release performance on the as-synthesized scaffold was studied in a phosphate buffered saline (PBS) solution. Vancomycin is found to be released in burst fashion within 24 h from the pristine BG scaffold, however, the release period from the G-CS-PVP/BG scaffold is enhanced to 7 days, indicating improved drug release properties of the G-CS-PVP/BG scaffold. Our results suggest that the G-CS-PVP/BG scaffolds possess promising physicochemical properties, sustained drug release capability and good biocompatibility for MC3T3-E1 cells' proliferation and adhesion, suggesting their potential applications in areas such as MC3T3-E1 cell stimulation and bone tissue engineering. - Highlights: • Novel genipi–chitosan–polyvinyl pyrrolidone/45S5 Bioglass® scaffolds are prepared. • Resistance to enzymatic degradation of the scaffold is improved significantly. • The resulting scaffold shows enhanced MC3T3-E1 cell adhesion and proliferation. • Release of antibiotic vancomycin from the

  2. Improving Oral Bioavailability of Sorafenib by Optimizing the "Spring" and "Parachute" Based on Molecular Interaction Mechanisms.

    Science.gov (United States)

    Liu, Chengyu; Chen, Zhen; Chen, Yuejie; Lu, Jia; Li, Yuan; Wang, Shujing; Wu, Guoliang; Qian, Feng

    2016-02-01

    Sorafenib is a clinically important oral tyrosine kinase inhibitor for the treatment of various cancers. However, the oral bioavailability of sorafenib tablet (Nexavar) is merely 38-49% relative to the oral solution, due to the low aqueous solubility of sorafenib and its relatively high daily dose. It is desirable to improve the oral bioavailability of sorafenib to expand the therapeutic window, reduce the drug resistance, and enhance patient compliance. In this study, we observed that the solubility of sorafenib could be increased ∼50-fold in the coexistence of poly(vinylpyrrolidone-vinyl acetate) (PVP-VA) and sodium lauryl sulfate (SLS), due to the formation of PVP-VA/SLS complexes at a lower critical aggregation concentration. The enhanced solubility provided a faster initial sorafenib dissolution rate, analogous to a forceful "spring" to release drug into solution, from tablets containing both PVP-VA and SLS. However, SLS appears to impair the ability of PVP-VA to act as an efficient "parachute" to keep the drug in solution and maintain drug supersaturation. Using 2D (1)H NMR, (13)C NMR, and FT-IR analysis, we concluded that the solubility enhancement and supersaturation of sorafenib were achieved by PVP-VA/SLS complexes and PVP-VA/sorafenib interaction, respectively, both through molecular interactions hinged on the PVP-VA VA groups. Therefore, a balance between "spring" and "parachute" must be carefully considered in formulation design. To confirm the in vivo relevance of these molecular interaction mechanisms, we prepared three tablet formulations containing PVP-VA alone, SLS alone, and PVP-VA/SLS in combination. The USP II in vitro dissolution and dog pharmacokinetic in vivo evaluation showed clear differentiation between these three formulations, and also good in vitro-in vivo correlation. The formulation containing PVP-VA alone demonstrated the best bioavailability with 1.85-fold and 1.79-fold increases in Cmax and AUC, respectively, compared with the

  3. pH-sensitive hydrogels

    Energy Technology Data Exchange (ETDEWEB)

    Jing-Fun, Yaung.

    1993-01-01

    This work dealt with the diffusant release from the polyvinyl-pyrrolidone-polyacrylic acid (PVP-PAA) semi-interpenetrating network (semi-IPN) film when the film was placed in separate aqueous dissolution media with various pH values. The pH effect on the swelling behavior of the film and the rates of diffusant release from the film were studied. The PVP-PAA semi-IPN films and the PVP-PAA complexes were prepared from photopolymerization of the mixture of PVP and acrylic acid, in the presence of benzin methyl ether. The PVP-PAA complexes were characterized by means of DSC and FT-IR. The PVP-PAA semi-IPN films with various percentages of a crosslinking agent were investigated. The study of pH effect on the swelling of the semi-IPN film was carried out in 0.1 N HCl solution, pH 3.0 and 6.0 buffers. The swelling rate of PVP-PAA semi-IPN film in pH 6.0 buffer was much higher than the rates in 0.1 N HCl and pH 3.0 buffer. The chemical to be released from the film was incorporated during the film preparation and the diffusant used was either caffeine (hydrogen-bonding-acceptor) or salicylamide (hydrogen-bonding-donator). The diffusant release from the PVP-PAA semi-IPN in 0.1 N HCl solution and in the phosphate buffers with various pH values was investigated. Release rate was faster in high pH media. The chemical valve function of the PVP-PAA semi-IPN film in controlling release rate was studied by alternating the dissolution medium between 0.1N HCl solution and pH 6.0 buffer. Consistently, the release rate increased when the dissolution medium was changed from 0.1 N HCl solution to pH 6.0 buffer, and the rate dropped while the medium was was switched from pH 6.0 buffer to 0.1 N HCl solution. Finally, the effects of the type of crosslinking agent, the percentage of crosslinking agent used, and the molar ratio of PVP/AA on the diffusant release from the PVP-PAA semi-IPN film were explored.

  4. Dehalogenation of Aryl Halides Catalyzed by Montmorillonite Immobilized Bimetal Catalyst in Aqueous System

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    A novel bisupported bimetal catalyst PVP-PdCl2-FeSO4/Al-Mont-PEG600 was prepared by immobilization of PVP (poly (N-vinyl-2-pyrrolidone)) supported bimetallic catalyst using alumina pillared inartificial montmorillonite as the carrier. This catalyst has good dehalogenation activity and selectivity to aryl halides-o-chlorotoluene in aqueous system in the presence of phase transfer catalyst (PEG) and sodium formate as hydrogen source. The catalyst also shows good reusability.

  5. Recoverable Palladium(0) on Poly(vinylpyrrolidone) Catalyzed Ligand-free Suzuki Reaction in Water

    Institute of Scientific and Technical Information of China (English)

    WANG Lei; LI Pin-Hua

    2006-01-01

    In the absence of any ligand, a recoverable palladium(O) on poly(vinylpyrrolidone) (PVP) catalyzed Suzuki reaction of aryl iodide and bromide with potassium aryltrifluoroborate was developed. The reaction conditions involved the use of water as the solvent, potassium carbonate as the base, and PVP supported palladium metal colloids as the catalyst. The palladium metal could be recovered and recycled for eight consecutive trials without significant loss of its activity.

  6. Comparative Analysis of the Paravertebral Analgesic Pump Catheter with the Epidural Catheter in Elderly Trauma Patients with Multiple Rib Fractures.

    Science.gov (United States)

    Shapiro, Brian S; Wasfie, Tarik; Chadwick, Mathew; Barber, Kimberly R; Yapchai, Raquel

    2017-04-01

    Presently, trauma guidelines recommend epidural analgesia as the optimal modality of pain relief from rib fractures. They are not ideally suited for elderly trauma patients and have disadvantages including bleeding risk. The paravertebral analgesic pump (PVP) eliminates such disadvantages and includes ease of placement in the trauma setting. This study compares pain control in patients treated by EPI versus PVP. This is a retrospective, historical cohort study comparing two methods of pain management in the trauma setting. Before 2010, patients who had epidural catheters (EPI) placed for pain control were compared with patients after 2010 in which the PVP was used. All patients had multiple rib fractures as diagnosed by CT scan. Analysis was adjusted for age, number of fractures, and comorbid conditions. Multiple linear regression analysis was conducted to compare average reported pain. A total of 110 patients, 31 PVP and 79 epidural catheters, were included in the study. Overall mean age was 65 years. The mean Injury Severity Score was 12.0 (EPI) and 11.1 (PVP). Mean number rib fractures was 4.29 (EPI) and 4.71 (PVP). PVP was associated with a 30 per cent greater decrease in pain than that seen with EPI (6.0-1.9 vs 6.4-3.4). After controlling for age, Injury Severity Score, and number of rib fractures, there were no differences in intensive care unit or total length of stay (P = 0.35) or in pain score (3.76 vs 3.56, P = 0.64). In conclusion, the PVP compares well with epidural analgesia in older trauma patients yet is safe, well tolerated, and easily inserted.

  7. Electrospun nanofibers of poly(vinyl pyrrolidone)/Eu3+ and its photoluminescence properties

    Institute of Scientific and Technical Information of China (English)

    Shan Shan Tang; Chang Lu Shao; Shou Zhu Li

    2007-01-01

    Nanofibers of poly(vinyl pyrrolidone) (PVP)/Eu3+ with diameters of 300-900 nm were prepared by using sol-gel processing and electrospinning technique. The products were characterized by scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FT-IR), and photoluminescence (PL). The results indicated that, Eu3+ was successfully embedded in the onedimensional hybrid nanofibers, and the PVP/Eu3+ hybrid nanofibers had favorable photoluminescence properties.

  8. Synthesis of Poly(N-vinylpyrrolidone) Nanofibers Containing Gold Nanoparticles via Electrospinning Technique

    Institute of Scientific and Technical Information of China (English)

    DU Jian-shi; YANG Qing-biao; BAI Jie; WANG Shu-gang; ZHANG Chao-qun; LI Yao-xian

    2007-01-01

    Poly(N-vinylpyrrolidone) (PVP) nanofibers containing gold nanoparticles were prepared by electrospinning method. This simple route was used to prepare composites on a large scale, and the syntheses are simple. The optical property of gold nanoparticles in PVP aqueous solution was investigated by UV-Visible absorption spectra. The morphology of the fibers and the distribution of particles were characterized by transmission electron microscopy. The structure of the composite was characterized by Fourier transform infrared spectroscopy.

  9. Photoselective vaporization of the prostate in men taking clopidogrel

    Directory of Open Access Journals (Sweden)

    Daniel M.G Spernat

    2011-01-01

    Conclusions : PVP is a safe and efficacious in the treatment of high risk patients with bladder outlet obstruction. Further, the ability to continue therapeutic anticoagulation and anti-platelet agents, is a significant advantage over Holmium enucleation of the prostate and conventional transurethral resection of the prostate. Larger studies with greater numbers of patients are required prior to PVP becoming the gold standard for high-risk patients with bladder outlet obstruction.

  10. Prominent periventricular fiber system related to ganglionic eminence and striatum in the human fetal cerebrum.

    Science.gov (United States)

    Vasung, L; Jovanov-Milošević, N; Pletikos, M; Mori, S; Judaš, M; Kostović, Ivica

    2011-01-01

    Periventricular pathway (PVP) system of the developing human cerebrum is situated medial to the intermediate zone in the close proximity to proliferative cell compartments. In order to elucidate chemical properties and developing trajectories of the PVP we used DTI in combination with acetylcholinesterase histochemistry, SNAP-25 immunocytochemistry and axonal cytoskeletal markers (SMI312, MAP1b) immunocytochemistry on postmortem paraformaldehyde-fixed brains of 30 human fetuses ranging in age from 10 to 38 postconceptional weeks (PCW), 2 infants (age 1-3 months) and 1 adult brain. The PVP appears in the early fetal period (10-13 PCW) as two defined fibre bundles: the corpus callosum (CC) and the fetal fronto-occipital fascicle (FOF). In the midfetal period (15-18 PCW), all four components of the PVP can be identified: (1) the CC, which at rostral levels forms a voluminous callosal plate; (2) the FOF, with SNAP-25-positive fibers; (3) the fronto-pontine pathway (FPP) which for a short distance runs within the PVP; and (4) the subcallosal fascicle of Muratoff (SFM) which contains cortico-caudate projections. The PVPs are situated medial to the internal capsule at the level of the cortico-striatal junction; they remain prominent during the late fetal and early preterm period (19-28 PCW) and represent a portion of the wider periventricular crossroad of growing associative, callosal and projection pathways. In the perinatal period, the PVPs change their topographical relationships, decrease in size and the FOF looses its SNAP-25-reactivity. In conclusion, the hitherto undescribed PVP of the human fetal cerebrum contains forerunners of adult associative and projection pathways. Its transient chemical properties and relative exuberance suggest that the PVP may exert influence on the development of cortical connectivity (intermediate targeting) and other neurogenetic events such as neuronal proliferation. The PVP's topographical position also indicates that it is a major

  11. Preparation of bacterial cellulose based hydrogels and their viscoelastic behavior

    OpenAIRE

    2015-01-01

    Bacterial cellulose (BC) based hydrogels have been prepared in blended with carboxymethylcellulose and polyvinyl pyrrolidone by using heat treatment. The properties of BC-CMC and BC-PVP hydrogels were compared with pure BC, CMC and PVP hydrogels. These hydrogels were investigated by measuring their structural, morphological and viscoelastic properties. Through the morphological images, alignment of the porous flake like structures could be seen clearly within the inter-polymeric network of th...

  12. Development and characterisation of soluble polymeric particles for pulmonary peptide delivery

    OpenAIRE

    Tewes, Frédéric; Tajber, Lidia; CORRIGAN, OWEN; Ehrhardt, Carsten; Healy, Anne-Marie

    2010-01-01

    PUBLISHED Pulmonary administration of protein and peptide drugs using inhaled dry powder particles is an interesting alternative to parenteral delivery. The stabilisation of these molecules is essential to the maintenance of biological activity in such inhalation formulations. Here salmon calcitonin (sCT) was co-spray dried with linear or branched PEG (L-PEG and B-PEG) and PVP in order to formulate aerosolisable particles of the bioactive peptide. Co-spray drying L-PEG and PVP resulted in ...

  13. Fabrication of channel waveguides from sol-gel-processed polyvinylpyrrolidone/ SiO(2) composite materials.

    Science.gov (United States)

    Yoshida, M; Prasad, P N

    1996-03-20

    Sol-gel-processed composite materials of polyvinylpyrrolidone (PVP) and SiO(2) were studied for optical waveguide applications. PVP is a polymer that can be crosslinked, so it is expected to have high thermal stability after crosslinking. However, thermal crosslinking and thermal decomposition of pure PVP take place around the same temperature, 200 °C, therefore pure PVP had a high optical propagation loss as a result of the absorption of the decomposed molecules after crosslinking. The incorporation of sol-gel-processed SiO(2) prevented the thermal decomposition of PVP and provided remarkably low optical propagation losses. The PVP/SiO(2)composite material also produced thick (>2-µm) crack-free films when the PVP concentration was 50% or higher. An optical propagation loss of 0.2 dB/cm was achieved at 633 nm in the 50% PVP/SiO(2) composite planar waveguide. Several aspects of the thermal stability of the waveguides were evaluated. The slab waveguide was then used for fabrication of channel waveguides with a selective laser-densification technique. This technique used metal lines fabricated with photolithography on the slab waveguide as a light absorbent, and these metal lines were heated by an Ar laser. The resultant channel waveguide had an optical propagation loss of 0.9 dB/ cm at 633 nm. This technique provides lower absorption loss and scattering loss compared with the direct laser-densification technique, which uses UV lasers, and produces narrow waveguides that are difficult to fabricate with a CO(2) laser.

  14. Percutaneous vertebroplasty of the entire thoracic and lumbar vertebrate for vertebral compression fractures related to chronic glucocorticosteriod use: Case report and review of literature

    Energy Technology Data Exchange (ETDEWEB)

    Tian, Qing Hwa; Wu, Chun Gen; Xiao, Quan; Ping; He, Cheng Jian; Gu, Yi Feng; Wang, Tao; Li, Ming Hua [Dept. of Diagnostic and Interventional Radiology, Shanghai Jiao Tong University Affiliated Sixth People' s Hospital, Shanghai (China)

    2014-12-15

    Glucocorticosteroid-induced osteoporosis is the most frequent of all secondary types of osteoporosis, and can increase the risk of vertebral compression fractures (VCFs). There are promising additions to current medical treatment for appropriately selected osteoporotic patients. Few studies have reported on the efficiency of percutaneous vertebroplasty (PVP) or kyphoplasty for whole thoracic and lumbar glucocorticosteroid-induced osteoporotic vertebral compression fractures. We report a case of a 67-year-old man with intractable pain caused by successional VCFs treated by PVP.

  15. The Study on Improved Cryopreservation Technique of The Ultrastructure of Corneal Endothelial Cells

    Institute of Scientific and Technical Information of China (English)

    1994-01-01

    The traditional corneal cryopreservation technique was improved. We carried out an experimental study that rabbit corneas were cryop-reserved by using polyvinylpyrolidone (PVP) as cryoprotective agent and dimethlsulfoxide (DMSO) as the control. The endothelia of cryopreserved corneas were evaluated by scanning and transmission electron microscopy and vital staining. The study shows that PVP is an excellent extracellular cryoprotective agent and has the characteristic of low toxicity or no toxicity to co...

  16. Complications of percutaneous vertebroplasty

    OpenAIRE

    Saracen, Agnieszka; Kotwica, Zbigniew

    2016-01-01

    Abstract Percutaneous vertebroplasty (PVP) is a minimally invasive procedure widely used for the treatment of pain due to vertebral fractures of different origins—osteoporotic, traumatic, or neoplastic. PVP is minimally invasive, but the complications are not rare; however, they are in most cases not significant clinically. The most frequent is cement leakage, which can occur onto veins, paravertebral soft tissue, into the intervertebral disk, or to the spinal canal, affecting foraminal area ...

  17. Fabrication of Worm-Like Nanorods and Ultrafine Nanospheres of Silver Via Solid-State Photochemical Decomposition

    OpenAIRE

    Navaladian S; Viswanathan B; Varadarajan TK; Viswanath RP

    2009-01-01

    Abstract Worm-like nanorods and nanospheres of silver have been synthesized by photochemical decomposition of silver oxalate in water by UV irradiation in the presence of CTAB and PVP, respectively. No external seeds have been employed for the synthesis of Ag nanorods. The synthesized Ag colloids have been characterized by UV-visible spectra, powder XRD, HRTEM, and selected area electron diffraction (SAED). Ag nanospheres of average size around 2 nm have been obtained in the presence of PVP. ...

  18. Microscale Electrospinning of Polymer Nanowires for Sensing Applications

    Science.gov (United States)

    2005-09-01

    Agilent 34970A Datalogger, Agilent Programmable Power Supply E3631A, VWR Heating/Cooling Bath, Aalborg Gas Flow Controllers, Nitrogen Carrier Gas, LabView ...2.00E-0 AX 200 1! • aPEO p• ePCi Pll P 000XPB I A,5 EBS= ×PVP PVP 0010 ,PIBO 0.000 ¥ x 0.I . A I 0 00 0000 0000 2000 0000 0000 0000 4000 4000 0 1000

  19. DNA Separation by Capillary Electrophoresis with Ultraviolet Detection using Mixed Synthetic Polymers

    Institute of Scientific and Technical Information of China (English)

    Qian WANG; Xu XU

    2003-01-01

    The mixtures of two polymers, poly (N,N-dimethylacrylamide) (PDMA) and polyvinylpyrrolidone (PVP) were synthesized and used as the separation medium for double-stranded and single-stranded DNA fragments by capillary electrophoresis with UV detector. On optimal conditions, 2%w/v PDMA ( 2%w/v PVP can be used to separate the doublet 123/124bp in pBR322/Hae III Markers.

  20. Hydrothermal effect and mechanical stress properties of carboxymethylcellulose based hydrogel food packaging.

    Science.gov (United States)

    Gregorova, Adriana; Saha, Nabanita; Kitano, Takeshi; Saha, Petr

    2015-03-01

    The PVP-CMC hydrogel film is biodegradable, transparent, flexible, hygroscopic and breathable material which can be used as a food packaging material. The hygroscopic character of CMC and PVP plays a big role in the changing of their mechanical properties where load carrying capacity is one of important criteria for packaging materials. This paper reports about the hydrothermal effect on the mechanical and viscoelastic properties of neat CMC, and PVP-CMC (20:80) hydrogel films under the conditions of combined multiple stress factors such as temperature, time, load, frequency and humidity. The dry films were studied by transient and dynamic oscillatory experiments using dynamic mechanical analyser combined with relative humidity chamber (DMA-RH). The mechanical properties of PVP-CMC hydrogel film at room temperature (25 °C), in the range of 0-30%RH remain steady. The 20 wt% of PVP in PVP-CMC hydrogel increases the stiffness of CMC from 2940 to 3260 MPa at 25 °C and 10%RH.

  1. Research on the preparation and antibacterial activity of hydroxypropyl chitosan biguanide hydrochloride membrane with iodine%羟丙基壳聚糖双胍盐酸盐碘膜的制备及抑菌性研究

    Institute of Scientific and Technical Information of China (English)

    谢琳琳; 徐宁宁; 曹焕; 图布新; 王倩; 丁德润

    2016-01-01

    利用“保护氨基-接枝反应-脱保护恢复氨基”方法合成壳聚糖衍生物-羟丙基壳聚糖双胍盐酸盐(HPCGH),并将其与PVP、明胶混合制备相应的衍生物膜HPCGH-PVP,HPCGH-PVP浸没于不同浓度的碘乙醇液中得含碘膜HPCGH-PVP-I2.用FT-IR、XRD、TG和DTG对衍生物进行表征,通过碘量法测定HPCGH-PVP对碘的吸附量.碘含量分析结果表明,HPCGH-PVP吸附碘能力较强,当碘乙醇液浓度为0.03mol/L时,其对碘吸附的最大质量比为m(HPCGH-PVP)∶m(I2)=1∶0.1908.抑菌性测试结果表明,HPCGH-PVP-I2的抑菌性优于HPCGH-PVP,且HPCGH-PVP-I2对E.coli和S.aureus的敏感度均属于高度敏感.

  2. Electrospinning preparation and electrical and biological properties of ferrocene/poly(vinylpyrrolidone composite nanofibers

    Directory of Open Access Journals (Sweden)

    Ji-Hong Chai

    2013-03-01

    Full Text Available Nanofibers containing ferrocene (Fc have been prepared for the first time by electrospinning. In this paper, Fc was dispersed uniformly throughout the poly(vinypyrrolidone (PVP matrix for the purpose of combining the properties of PVP and Fc. The effects of solvents and Fc concentration on the morphologies and diameters of nanofibers were investigated. In the DMF/ethanol solvent, the morphologies of the obtained nanofibers significantly changed with the increase of Fc concentration. The results demonstrated that the morphologies of the nanofibers could be controlled through adjusting solvents and Fc concentration. Scanning electron microscopy (SEM showed that the diameters of the obtained composite fibers were about 30–200 nm at different Fc concentrations. Thermogravimetric analysis (TGA results confirmed the presence of ferrocene within the PVP nanofibers. X-ray diffraction (XRD results showed that the crystalline structure of Fc in the fibers was amorphous after the electrospinning process. A biological evaluation of the antimicrobial activity of Fc/PVP nanofibers was carried out by using Gram-negative Escherichia coli (E. coli as model organisms. The nanofibers fabricated by this method showed obvious antibacterial activity. Electrochemical properties were characterized based on cyclic voltammetry measurements. The CV results showed redox peaks corresponding to the Fc+/Fc couple, which suggested that Fc molecules encapsulated inside PVP nanofibers retian their electrochemical activity. The properties and facile preparation method make the Fc/PVP nanofibers promising for antibacterial and sensing applications.

  3. Monodisperse polyvinylpyrrolidone-coated CoFe2O4 nanoparticles: Synthesis, characterization and cytotoxicity study

    Science.gov (United States)

    Wang, Guangshuo; Ma, Yingying; Mu, Jingbo; Zhang, Zhixiao; Zhang, Xiaoliang; Zhang, Lina; Che, Hongwei; Bai, Yongmei; Hou, Junxian; Xie, Hailong

    2016-03-01

    In this study, monodisperse cobalt ferrite (CoFe2O4) nanoparticles were prepared successfully with various additions of polyvinylpyrrolidone (PVP) by sonochemical method, in which PVP served as a stabilizer and dispersant. The effects and roles of PVP on the morphology, microstructure and magnetic properties of the obtained CoFe2O4 were investigated in detail by X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and superconducting quantum interference device (SQUID). It was found that PVP-coated CoFe2O4 showed relatively well dispersion with narrow size distribution. The field-dependent magnetization curves indicated superparamagnetic behavior of PVP-coated CoFe2O4 with moderate saturation magnetization and hydrophilic character at room temperature. More importantly, the in vitro cytotoxicity testing exhibited negligible cytotoxicity of as-prepared PVP-CoFe2O4 even at the concentration as high as 150 μg/mL after 24 h treatment. Considering the superparamagnetic properties, hydrophilic character and negligible cytotoxicity, the monodisperse CoFe2O4 nanoparticles hold great potential in a variety of biomedical applications.

  4. Performance evaluation and mass transfer study of CO{sub 2} absorption in flat sheet membrane contactor using novel porous polysulfone membrane

    Energy Technology Data Exchange (ETDEWEB)

    Nabian, Nima; Ghoreyshi, Ali Asghar; Rahimpour, Ahmad; Shakeri, Mohsen [Babol University of Technology, Babol (Iran, Islamic Republic of)

    2015-11-15

    The performance of gas-liquid membrane contactor for CO{sub 2} capture was investigated using a novel polysulfone (PSF) flat membrane prepared via non-solvent phase inversion method. Polyvinyl pyrrolidone (PVP) was used as an additive in the dope solution of PSF membranes. Morphological studies by scanning electron microscopy (SEM) analysis revealed that PSF membrane with PVP has a finger-like structure, but the PSF membrane without PVP has a sponge-like structure. Also, characterization results through atomic force microscopy (AFM) and contact angle measurement demonstrated that the porosity, surface roughness and hydrophobicity of the PSF membrane increased with addition of PVP to the dope solution. Mass transfer resistance analysis, based on CO{sub 2} absorption flux, displayed that addition of PVP to the dope solution of PSF membrane decreased membrane mass transfer resistance, and significantly improved CO{sub 2} absorption flux up to 2.7 and 1.8 times of absorption fluxes of PSF membrane without PVP and commercial PVDF, respectively.

  5. Effect of binders on 500mg metformin hydrochloride tablets produced by wet granulation

    Directory of Open Access Journals (Sweden)

    LUCIANA CATIA BLOCK

    2009-12-01

    Full Text Available Metformin hydrochloride (MH is an oral hypoglycemic agent and a high-dose drug that has poor flow and compression properties. In this study, the feasibility of developing adequate, low cost 500mg tablets of metformin hydrochloride by wet granulation was tested with several binders (Starch / PVP K30®; Starch 1500® /PVP K30®, PVP K30® and PVP K90® in a simple tablet press of the type used in small pharmaceutical laboratories. The drug powder was tested for ability to flow, by determining Carr’s Index (CI and the Hausner ratio (HR. Differential scanning calorimetry and thermogravimetric analysis were carried out on isolated MH and 1:1 (w/w binary mixtures with the excipients. The size distribution, friability, flow properties and drug content of the granules were analyzed, as were the hardness, friability, disintegration, dissolution and uniformity of the dosage form. The drug powder showed CI > 22% and HR > 1.25, characteristic of a poor flow powder, and no significant incompatibilities with the excipients. All the granules showed adequate flow properties and were suitable for pressing into tablets, all of which complied with pharmacopeial specifications. The starch /PVP K30® and starch 1500® /PVP K30® mixtures were best for producing 500 mg MH tablets. Keywords: Metformin hydrochloride. Tablets. Wet granulation. Binders.

  6. Polyvinylpyrrolidone/polyvinyl butyral composite as a stable binder for castable supercapacitor electrodes in aqueous electrolytes

    Science.gov (United States)

    Aslan, M.; Weingarth, D.; Herbeck-Engel, P.; Grobelsek, I.; Presser, V.

    2015-04-01

    Mixtures of polyvinylpyrrolidone/polyvinyl butyral (PVP/PVB) are attractive binders for the preparation of carbon electrodes for aqueous electrolyte supercapacitors. The use of PVP/PVB offers several key advantages: They are soluble in ethanol and can be used to spray coat or drain cast activated carbon (AC) electrodes directly on a current collector. Infrared spectroscopy and contact angle measurements show that the PVP-to-PVB ratio determines the degree of binder hydrophilicity. Within our study, the most favorable performance was obtained for AC electrodes with a composition of AC + 1.5 mass% PVP + 6.0 mass% PVB; such electrodes were mechanically stabile and water resistant with a PVP release of less than 5% of total PVP while PVB itself is water insoluble. Compared to when using PVDF, the specific surface area (SSA) of the assembled electrodes was 10% higher, indicating a reduced pore blocking tendency. A good electrochemical performance was observed in different aqueous electrolytes for composite electrodes with the optimized binder composition: 160 F g-1 at 1 A g-1 for 1 M H2SO4 and 6 M KOH and 120 F g-1 for 1 M NaCl. The capacitance was slightly reduced by 2.5% after cycling to 1.2 V with 1.28 A g-1 in 1 M NaCl for 10,000 times.

  7. Fabrication and characterization of superparamagnetic poly(vinyl pyrrolidone)/poly(L-lactide)/Fe{sub 3}O{sub 4} electrospun membranes

    Energy Technology Data Exchange (ETDEWEB)

    Savva, Ioanna; Constantinou, Demetris [University of Cyprus, Department of Mechanical and Manufacturing Engineering, Nicosia (Cyprus); Marinica, Oana [National Center for Engineering of Systems with Complex Fluids, University “Politehnica” Timisoara, Timisoara (Romania); Vasile, Eugeniu [METAV Research and Development, Bucharest (Romania); Vekas, Ladislau [Center for Fundamental and Advanced Technical Research, Romanian Academy, Timisoara Branch, Timisoara (Romania); Krasia-Christoforou, Theodora, E-mail: krasia@ucy.ac.cy [University of Cyprus, Department of Mechanical and Manufacturing Engineering, Nicosia (Cyprus)

    2014-02-15

    The fabrication of magnetoactive fibrous nanocomposite membranes based on poly(vinyl pyrrolidone) (PVP), poly(L-lactide) (PLLA) and pre-formed oleic acid coated magnetite nanoparticles (OA Fe{sub 3}O{sub 4}) is presented. The aforementioned materials have been prepared by means of the electrospinning technique following a single-step fabrication process. The PVP/PLLA/OA Fe{sub 3}O{sub 4} nanocomposite membranes were characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) that provided information on the fiber diameters as well as on the morphological and dimensional characteristics of the OA Fe{sub 3}O{sub 4} nanoparticles embedded within the fibers. The thermal stability of these materials was evaluated by means of thermal gravimetric analysis (TGA) measurements. Finally, vibrational sample magnetometry (VSM) analysis disclosed superparamagnetic behavior at room temperature. The combination of the hydrophilic, biocompatible and photo-crosslinkable PVP with the biodegradable PLLA and the superparamagnetic OA Fe{sub 3}O{sub 4} nanoparticles within these materials allows for the future development of crosslinked fibrous magnetoactive nanocomposites exhibiting high stability in aqueous solutions, with potential use in biomedical and environmental applications. - Highlights: • Fabrication and characterization of electrospun fibrous membranes. • PVP and PVP/PLLA membranes. • PVP/PLLA/Fe{sub 3}O{sub 4} magnetoactive nanocomposite membranes. • Tunable superparamagnetic behavior at room temperature.

  8. A co-immobilized mediator and microorganism mediated method combined pretreatment by TiO2 nanotubes used for BOD measurement.

    Science.gov (United States)

    Liu, Ling; Zhang, Shengsen; Xing, Li; Zhao, Huijun; Dong, Shaojun

    2012-05-15

    In this paper, we proposed a method by using co-immobilized Escherichia coli (E. coli) as a biocatalyst and neutral red (NR) as an artificial electronic acceptor to modify glassy carbon electrode (GCE) for biochemical oxygen demand (BOD) measurement. Two different modification approaches of GCE were utilized and compared. In one approach, NR was electropolymerized on the surface of GCE, and E. coli cells were mixed with grafting copolymer PVA-g-PVP (briefly gPVP) and covered on NR polymer film to obtain a (gPVP/E. coli)/PNR/GCE. In the second approach, both NR and E. coli cells were mixed with the copolymer gPVP and modified GCE, after drying, which was electrochemically treated similar as above for obtaining a (gPVP/E. coli/NR)p/GCE. Based on the electrochemical evaluation, the performance of the latter was better, which may be caused by that the NR deposited on the surface of E. coli resulting in a good electron transport and permeability of cells membrane. To develop the results obtained at (gPVP/E. coli/NR)p/GCE further, the pretreatment by TiO(2) nanotubes arrays (TNTs) was employed, and different effects on samples of GGA, OECD, urea and real wastewater were evaluated. These results suggest that the present method holds a potential application for rapid BOD biosensor.

  9. Fading Spectrophotometric Method for the Determination of Polyvinylpyrrolidone with Eosin Y

    Institute of Scientific and Technical Information of China (English)

    YU Lihong; LIU Zhongfang; LIU Shaopu; HU Xiaoli; LIU Linfeng

    2009-01-01

    In weak acid medium,eosin Y (EY) has a strong absorption band in the visible light region,and the maximum absorption wavelength (λmax) is at 517 nm.There is no light absorption for polyvinylpyrrolidone (PVP) in 250-700 nm.When EY was reacted with PVP to form a binding product,a fading reaction of EY appeared and the maximum fading wavelength was still located at 517 nm.At the same time,a smaller absorption peak was observed at 545 nm.The extent of the fading (△A) is directly proportional to the concentration of PVP in the range of 0.40-3.20 mg·L-1.The fading reaction has high sensitivity.The molar absorptivity (ε) is 6.4×106 L·mol 1·cm-1 and the detection limit for PVP is 0.12 mg·L-1.The influencing factors for the reaction have been studied,and the results show that the selectivity is good.Based on this fact,a new fading spectrophotometric method for the determination of PVP with EY has been developed,which is simple and rapid,and it can be applied to the quantitative determination of PVP in beer samples.

  10. Antifouling and antimicrobial polymer membranes based on bioinspired polydopamine and strong hydrogen-bonded poly(N-vinyl pyrrolidone).

    Science.gov (United States)

    Jiang, Jinhong; Zhu, Liping; Zhu, Lijing; Zhang, Hongtao; Zhu, Baoku; Xu, Youyi

    2013-12-26

    A facile and versatile approach for the preparation of antifouling and antimicrobial polymer membranes has been developed on the basis of bioinspired polydopamine (PDA) in this work. It is well-known that a tightly adherent PDA layer can be generated over a wide range of material surfaces through a simple dip-coating process in dopamine aqueous solution. The resulting PDA coating is prone to be further surface-tailored and functionalized via secondary treatments because of its robust reactivity. Herein, a typical hydrophobic polypropylene (PP) porous membrane was first coated with a PDA layer and then further modified by poly(N-vinyl pyrrolidone) (PVP) via multiple hydrogen-bonding interactions between PVP and PDA. Data of water contact angle measurements showed that hydrophilicity and wettability of the membranes were significantly improved after introducing PDA and PVP layers. Both permeation fluxes and antifouling properties of the modified membranes were enhanced as evaluated in oil/water emulsion filtration, protein filtration, and adsorption tests. Furthermore, the modified membranes showed remarkable antimicrobial activity after iodine complexation with the PVP layer. The PVP layer immobilized on the membrane had satisfying long-term stability and durability because of the strong noncovalent forces between PVP and PDA coating. The strategy of material surface modification reported here is substrate-independent, and applicable to a broad range of materials and geometries, which allows effective development of materials with novel functional coatings based on the mussel-inspired surface chemistry.

  11. NOVEL AMPHIPHILIC FLUORESCENT GRAFT COPOLYMER: SYNTHESIS,CHARACTERIZATION AND ENCAPSULATION OF A HYDROPHOBIC AGENT

    Institute of Scientific and Technical Information of China (English)

    Zhao-qiang Wu; Shu Yang; Wen-yan Liao; Ling-zhi Meng

    2006-01-01

    Novel amphiphilic fluorescent graft copolymer (PVP-PyAHy) was successfully synthesized by the free radical copolymerization of hydrophobic monomer N-(1-pyrenebutyryl)-N'-acryloyl hydrazide (PyAHy) with hydrophilic precursor polymers of vinyl-functionalized poly(N-vinylpyrrolidone) (PVP) in DMF. The copolymer is amphiphilic and has intrinsic fluorescence. FT-IR, 1H-NMR, TEM, gel permeation chromatography-multi-angle laser light scattering, UV-Vis spectroscopy and fluorescence spectroscopy were used to characterize this copolymer. The TEM observation shows that the copolymer PVP-PyAHy forms micelles in aqueous solution. Results of fluorometric measurements illustrate that the critical micelle concentration (CMC) value of PVP-PyAHy in aqueous solution is about 0.90 mg/mL. To examine the encapsulation ability of the copolymer in aqueous media, methyl yellow was employed as a model hydrophobic agent. The loading level of the polymer to methyl yellow is 8.8 mg/g. The cytotoxicity assays for Madin Darby Canine Kidney (MDCK) cells shows good biocompatibility of PVP-PyAHy in vitro. These results suggest the potential of this copolymer PVP-PyAHy as drugs delivery carrier and fluorescent tracer.

  12. Hydrogen Bonding Interactions in Amorphous Indomethacin and Its Amorphous Solid Dispersions with Poly(vinylpyrrolidone) and Poly(vinylpyrrolidone-co-vinyl acetate) Studied Using (13)C Solid-State NMR.

    Science.gov (United States)

    Yuan, Xiaoda; Xiang, Tian-Xiang; Anderson, Bradley D; Munson, Eric J

    2015-12-07

    Hydrogen bonding interactions in amorphous indomethacin and amorphous solid dispersions of indomethacin with poly(vinylpyrrolidone), or PVP, and poly(vinylpyrrolidone-co-vinyl acetate), or PVP/VA, were investigated quantitatively using solid-state NMR spectroscopy. Indomethacin that was (13)C isotopically labeled at the carboxylic acid carbon was used to selectively analyze the carbonyl region of the spectrum. Deconvolution of the carboxylic acid carbon peak revealed that 59% of amorphous indomethacin molecules were hydrogen bonded through carboxylic acid cyclic dimers, 15% were in disordered carboxylic acid chains, 19% were hydrogen bonded through carboxylic acid and amide interactions, and the remaining 7% were free of hydrogen bonds. The standard dimerization enthalpy and entropy of amorphous indomethacin were estimated to be -38 kJ/mol and -91 J/(mol · K), respectively, using polystyrene as the "solvent". Polymers such as PVP and PVP/VA disrupted indomethacin self-interactions and formed hydrogen bonds with the drug. The carboxylic acid dimers were almost completely disrupted with 50% (wt) of PVP or PVP/VA. The fraction of disordered carboxylic acid chains also decreased as the polymer content increased. The solid-state NMR results were compared with molecular dynamics (MD) simulations from the literature. The present work highlights the potential of (13)C solid-state NMR to detect and quantify various hydrogen bonded species in amorphous solid dispersions as well as to serve as an experimental validation of MD simulations.

  13. Frozen-thawed spermatozoa from oligozoospermic ejaculates are susceptible to in situ DNA fragmentation in polyvinylpyrrolidone-based sperm-immobilization medium.

    Science.gov (United States)

    Salian, Sujit Raj; Kalthur, Guruprasad; Uppangala, Shubhashree; Kumar, Pratap; Adiga, Satish Kumar

    2012-08-01

    To elucidate the effect of sperm immobilization media that are and are not based on polyvinylpyrrolidone (PVP) on the DNA integrity of fresh and frozen-thawed spermatozoa during standard intracytoplasmic sperm injection (ICSI) conditions. Experimental prospective study. Embryology research laboratory. Forty-six ejaculates from normozoospermic and oligozoospermic men. Assessment of sperm DNA fragmentation by single-cell gel electrophoresis assay. DNA integrity of fresh and frozen-thawed spermatozoa from normozoospermic and oligozoospermic ejaculates exposed to PVP-based and non-PVP-based media. Exposure of fresh and frozen thawed spermatozoa from normozoospermic and oligozoospermic ejaculates to PVP-based medium in an ICSI dish for 30 minutes statistically significantly increased the DNA fragmentation. In contrast, the extent of DNA fragmentation in non-PVP-based medium did not statistically significantly differ from control. A PVP-based medium can induce a statistically significant amount of sperm DNA fragmentation in an ICSI dish, and frozen-thawed sperm from oligozoospermic ejaculates are more susceptible to in situ DNA fragmentation. Copyright © 2012 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.

  14. Development and characterisation of soluble polymeric particles for pulmonary peptide delivery.

    Science.gov (United States)

    Tewes, F; Tajber, L; Corrigan, O I; Ehrhardt, C; Healy, A M

    2010-10-09

    Pulmonary administration of protein and peptide drugs using inhaled dry powder particles is an interesting alternative to parenteral delivery. The stabilisation of these molecules is essential to the maintenance of biological activity in such inhalation formulations. Here salmon calcitonin (sCT) was co-spray dried with linear or branched PEG (L-PEG and B-PEG) and PVP in order to formulate aerosolisable particles of the bioactive peptide. Co-spray drying L-PEG and PVP resulted in porous particles, with minimal D(50) (median volume diameter) and MMAD (mass median aerodynamic diameter) values obtained for a PEG/PVP w/w ratio of 1. For particles based on both L-PEG and B-PEG, an increase in acetone, a poor solvent for the PVP, up to 70wt% of the spray dried solution led to a decrease in D(50) and MMAD. Crystallinity of PEG in the particles ranged between 90 and 97% when the PVP content varied between 15 and 70wt%, indicating a low degree of interaction between PVP and PEG. Additionally, dynamic vapour sorption analysis showed that an increase in PVP content increased the particle surface hygroscopicity. Hence, particle properties were adjusted by altering the water/acetone and PEG/PVP ratio in the spray dried solutions. PVP present at the particles surface protects them from melting during the spray drying process but also increases their hygroscopicity, adversely affecting their aerodynamic properties. Targeting a 5wt% of sCT loading resulted in a loading efficiency of 77.9 and 83.6% with L-PEG and B-PEG-based particles, respectively. Loading of sCT in L-PEG or B-PEG-based particles modified particle roughness and D(50), leading to an increase in MMAD of the L-PEG-based particles. However, particles were still considered to be suitable for aerosolisation as their FPFs (fine particle fractions) were higher than 30%. These particles formulated with PVP and PEG allowed sCT biological activity to be maintained when evaluated by measuring cAMP production by T47D cells.

  15. In-vivo optical detection of cancer using chlorin e6 – polyvinylpyrrolidone induced fluorescence imaging and spectroscopy

    Directory of Open Access Journals (Sweden)

    Soo Khee

    2009-01-01

    Full Text Available Abstract Background Photosensitizer based fluorescence imaging and spectroscopy is fast becoming a promising approach for cancer detection. The purpose of this study was to examine the use of the photosensitizer chlorin e6 (Ce6 formulated in polyvinylpyrrolidone (PVP as a potential exogenous fluorophore for fluorescence imaging and spectroscopic detection of human cancer tissue xenografted in preclinical models as well as in a patient. Methods Fluorescence imaging was performed on MGH human bladder tumor xenografted on both the chick chorioallantoic membrane (CAM and the murine model using a fluorescence endoscopy imaging system. In addition, fiber optic based fluorescence spectroscopy was performed on tumors and various normal organs in the same mice to validate the macroscopic images. In one patient, fluorescence imaging was performed on angiosarcoma lesions and normal skin in conjunction with fluorescence spectroscopy to validate Ce6-PVP induced fluorescence visual assessment of the lesions. Results Margins of tumor xenografts in the CAM model were clearly outlined under fluorescence imaging. Ce6-PVP-induced fluorescence imaging yielded a specificity of 83% on the CAM model. In mice, fluorescence intensity of Ce6-PVP was higher in bladder tumor compared to adjacent muscle and normal bladder. Clinical results confirmed that fluorescence imaging clearly captured the fluorescence of Ce6-PVP in angiosarcoma lesions and good correlation was found between fluorescence imaging and spectral measurement in the patient. Conclusion Combination of Ce6-PVP induced fluorescence imaging and spectroscopy could allow for optical detection and discrimination between cancer and the surrounding normal tissues. Ce6-PVP seems to be a promising fluorophore for fluorescence diagnosis of cancer.

  16. Gamma Irradiation Synthesis and Influence the Optical and Thermal Properties of Cadmium Sulfide (CdS/Poly (Vinyl Pyrolidone Nanocomposites

    Directory of Open Access Journals (Sweden)

    Shawkat S. Gasaymeh

    2010-01-01

    Full Text Available Problem statement: Gamma irradiation has been successfully used to prepare a spherical cadmium sulfide CdS/Poly Vinylpyrolidone (PVP quantum dots nanoparticles with enhancement of their optical band gap energy and thermal properties at room temperature and under ambient pressure. Sodium thiosulfate was used as a sulfur source in an aqueous solution. The formation of lower band gap energy of CdS/PVP nanoparticles and thermal stability can be controlled by using different irradiation doses. TEM images showed that the CdS/PVP particle size tends to be smaller and with better distribution as irradiation dose increases. Approach: Gamma (γ irradiation offered many advantages for the preparation of metal nanoparticles by producing large number of hydrated electrons during γ-ray irradiation, which can reduce the metal ions to zero valiant metal particles. Results: CdS/PVP nanoparticles were successfully prepared in one-step by γ-irradiation technique in an aqueous system at room temperature and under ambient pressure. The particle size was found to be less than 10 nm based on the Transmission Electron Microscopy (TEM that depended on the irradiation doses value, which showed a well distribution with a controlled size as doses change. The presence of PVP polymer was considered an important reason that influenced the shape and the distribution of those nanoparticles. The optical band gap energy of those nanoparticles was calculated by using the UV-VIS absorption spectra. Thermal analysis TGA showed that the composite had a higher degradation temperature than the PVP alone. A possible mechanism of the formation of cadmium sulfide by irradiation system was proposed. Conclusion: This result indicated that CdSO4 can effectively dope PVP and enhance the optical and thermal properties. In addition, γ-irradiation is an effective technique for preparing inorganic/organic nanocomposites.

  17. Study of chemical interaction induced by ionizing radiation poly(dimethylsiloxane-g-ethylene oxide) in the poly(n-vinyl-2-pyrrolidone) and agar membrane; Estudo da interacao quimica do poli(dimetilsiloxano-g-oxido de etileno) na membrana de poli(n-vinil-2-pirrolidona) e agar induzida com radiacao ionizante

    Energy Technology Data Exchange (ETDEWEB)

    Bazzi, Aurea de Souza

    1999-07-01

    Membrane composed by poly(N-vinyl-2-pyrrolidone) (PVP) and agar was formulated with and without poly(dimethylsiloxane-g-ethylene oxide) (SEO) irradiated with electron beam with doses between 10-50 kGy. The radiolytic behaviour of each component, PVP, agar and SEO, was studied when irradiated by gamma ray, in the absence and presence of air and water, by electron paramagnetic resonance (EPR) at 77 K. The chemical interaction of SEO with PVP/agar membrane was investigated by: infrared spectroscopy, energy dispersive X-ray fluorescence, dynamic-mechanical analysis, scanning electron microscopy, gel and swelling analysis. The cytotoxicity of the PVP/agar/SEO membrane was evaluated by cellular suppression. The membrane radicals from PVP ({phi}NC.) and from water (H., OH. and H{sub 2}O) was observed by EPR at 77K. The agar radicals formed by hydrogen abstraction of C{sub 1} and C{sub 3} of {beta}-D-galactose and/or C{sub 1} and C{sub 4} of {alpha}-L-galactose, reacted primarily with water radicals in despite of they also took part in the membrane by chemical bond. The radicals from SEO (.CH{sub 2}{approx}, .Si{approx}, .O{approx}) participated in the inter and intramolecular crosslinking as co-crosslinker by polymeric bridge. The co-crosslinked action depended on its concentration associated to PVP concentration. The presence op acrylates increases the tensile break of the PVP/agar/SEO membrane significantly. (author)

  18. A new Plasmodium vivax reference sequence with improved assembly of the subtelomeres reveals an abundance of pir genes [version 1; referees: 2 approved

    Directory of Open Access Journals (Sweden)

    Sarah Auburn

    2016-11-01

    Full Text Available Plasmodium vivax is now the predominant cause of malaria in the Asia-Pacific, South America and Horn of Africa. Laboratory studies of this species are constrained by the inability to maintain the parasite in continuous ex vivo culture, but genomic approaches provide an alternative and complementary avenue to investigate the parasite’s biology and epidemiology. To date, molecular studies of P. vivax have relied on the Salvador-I reference genome sequence, derived from a monkey-adapted strain from South America. However, the Salvador-I reference remains highly fragmented with over 2500 unassembled scaffolds.  Using high-depth Illumina sequence data, we assembled and annotated a new reference sequence, PvP01, sourced directly from a patient from Papua Indonesia. Draft assemblies of isolates from China (PvC01 and Thailand (PvT01 were also prepared for comparative purposes. The quality of the PvP01 assembly is improved greatly over Salvador-I, with fragmentation reduced to 226 scaffolds. Detailed manual curation has ensured highly comprehensive annotation, with functions attributed to 58% core genes in PvP01 versus 38% in Salvador-I. The assemblies of PvP01, PvC01 and PvT01 are larger than that of Salvador-I (28-30 versus 27 Mb, owing to improved assembly of the subtelomeres.  An extensive repertoire of over 1200 Plasmodium interspersed repeat (pir genes were identified in PvP01 compared to 346 in Salvador-I, suggesting a vital role in parasite survival or development. The manually curated PvP01 reference and PvC01 and PvT01 draft assemblies are important new resources to study vivax malaria. PvP01 is maintained at GeneDB and ongoing curation will ensure continual improvements in assembly and annotation quality.

  19. Utilization of natural polysaccharides by radiation in Korea

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Young Keun; Young Chang Nho [Korea Atomic Energy Research Institute, Taejon (Korea)

    2001-03-01

    Radiation can induce a chemical reaction to modify polymer under even solid conditions or in low temperatures. Radiation crosslinking can be easily adjusted and is easily reproducible by controlling the radiation dose. The finished product contains no residues of substances required to initiate the chemical crosslinking which can restrict the application possibilities. In these studies, hydrogels from a mixture of chitosan and polyvinyl alcohol (PVA)/Poly-N-vinylpyrrolidone (PVP) were made by 'freezing and thawing', or gamma-ray irradiation or two steps of 'freezing and thawing' and gamma-ray irradiation for wound dressing. Mechanical properties such as gelation, water absorptivity, and gel strength were examined to evaluate the hydrogels for wound dressing. The composition of PVA:PVP was 60:40, PVA/PVP: chitosan ratio was in the range 9:1 - 7:3, and the solid concentration of PVA/PVP/chitosan solution was 15wt%. Gamma irradiation doses of 25, 35,50, 60 and 70kGy were exposed to a mixture of PVA/PVP/chitosan to evaluate the effect of irradiation dose on the mechanical properties of hydrogels. Water-soluble chitosan was used in this experiment. The gelation of hydrogels was higher when two steps of 'freezing and thawing' and irradiation were used than when only 'freezing and thawing' was utilized. Gel content was influenced slightly by PVA/PVP: chitosan composition and irradiation dose, but swelling was influenced greatly by them. The swelling percent was much increased as the composition of chitosan in PVA/PVP/chitosan increased. (author)

  20. Lithium ion conducting solid polymer blend electrolyte based on bio-degradable polymers

    Indian Academy of Sciences (India)

    Natarajan Rajeswari; Subramanian Selvasekarapandian; Moni Prabu; Shunmugavel Karthikeyan; C Sanjeeviraja

    2013-04-01

    Lithium ion conducting polymer blend electrolyte films based on poly(vinyl alcohol) (PVA) and poly(vinyl pyrrolidone) (PVP) with different Mwt% of lithium nitrate (LiNO3) salt, using a solution cast technique, have been prepared. The polymer blend electrolyte has been characterized by XRD, FTIR, DSC and impedance analyses. The XRD study reveals the amorphous nature of the polymer electrolyte. The FTIR study confirms the complex formation between the polymer and salt. The shifts in g values of 70 PVA–30 PVP blend and 70 PVA–30 PVP with different Mwt% of LiNO3 electrolytes shown by DSC thermograms indicate an interaction between the polymer and the salt. The dependence of g and conductivity upon salt concentration has been discussed. The ion conductivity of the prepared polymer electrolyte has been found by a.c. impedance spectroscopic analysis. The PVA–PVP blend system with a composition of 70 wt% PVA: 30 wt% PVP exhibits the highest conductivity of 1.58 × 10-6 Scm-1 at room temperature. Polymer samples of 70 wt% PVA–30 wt% PVP blend with different molecular weight percentage of lithium nitrate with DMSO as solvent have been prepared and studied. High conductivity of 6.828 × 10-4 Scm-1 has been observed for the composition of 70 PVA:30 PVP:25 Mwt% of LiNO3 with low activation energy 0.2673 eV. The conductivity is found to increase with increase in temperature. The temperature dependent conductivity of the polymer electrolyte follows the Arrhenius relationship which shows hopping of ions in the polymer matrix. The relaxation parameters () and () of the complexes have been calculated by using loss tangent spectra. The mechanical properties of polymer blend electrolyte such as tensile strength, elongation and degree of swelling have been measured and the results are presented.

  1. Safety and feasibility of percutaneous vertebroplasty with radioactive {sup 153}Sm PMMA in an animal model

    Energy Technology Data Exchange (ETDEWEB)

    Lu Jun [Department of Radiotherapy, Xijing Hospital, Fourth Military Medical University, 15 West Changle Road, Xi' an 710032, Shaanxi Province (China); Deng Jinglan, E-mail: dengjinglan@gmail.com [Department of Nuclear Medicine, Xijing Hospital, Fourth Military Medical University, 15 West Changle Road, Xi' an 710032, Shaanxi Province (China); Zhao Haitao [Department of Radiology, Xijing Hospital, Fourth Military Medical University, 15 West Changle Road, Xi' an 710032, Shaanxi Province (China); Shi Mei [Department of Radiotherapy, Xijing Hospital, Fourth Military Medical University, 15 West Changle Road, Xi' an 710032, Shaanxi Province (China); Wang Jing [Department of Nuclear Medicine, Xijing Hospital, Fourth Military Medical University, 15 West Changle Road, Xi' an 710032, Shaanxi Province (China); Zhao Lina [Department of Radiotherapy, Xijing Hospital, Fourth Military Medical University, 15 West Changle Road, Xi' an 710032, Shaanxi Province (China)

    2011-05-15

    Purpose: We investigated the safety and feasibility of the combination of samarium-153-ethylenediamine tetramethylene phosphonate ({sup 153}Sm-EDTMP)-incorporated bone cement (BC) with percutaneous vertebroplasty (PVP) in dogs. Methods and materials: {sup 153}Sm-EDTMP-incorporated BC was prepared by combining solid {sup 153}Sm-EDTMP and polymethylmethacrylate (PMMA) immediately before PVP. It was then injected into the vertebrae of four healthy mongrel dogs (two males and two females) by PVP under CT guidance. Each dog was subjected to five PVP sessions at a {sup 153}Sm-EDTMP dose of 30-70 mCi. The suppressive effect of local injection of {sup 153}Sm-EDTMP on the hematopoietic system was evaluated through counting of peripheral blood cells. Distribution of {sup 153}Sm-EDTMP-incorporated BC and the status of tissues adjacent to injected vertebrae were evaluated with SPECT, CT and MRI. Histopathology was carried out to assess the influence of PVP on the vertebra and adjacent tissues at the microscopic level. Results: PVP was done successfully, and all dogs exhibited normal behavior and stable physical signs after procedures. {sup 153}Sm-EDTMP-incorporated BC was concentrated mainly in target vertebrae, and the peripheral blood cells remained within normal range. The spinal cord and tissues around BC did not exhibit signs of injury even when the dosage of {sup 153}Sm-EDTMP increased from 30 mCi to 70 mCi. Conclusion: A dose lower than 70 mCi of {sup 153}Sm is safe when it was injected into vertebrae. {sup 153}Sm-EDTMP-incorporated BC did not influence the effect of PVP. This means might strengthen anti-tumor activity locally for vertebra with osseous metastasis without damaging adjacent tissues.

  2. Photoselective vaporization of the prostate with GreenLight 120-W laser versus transurethral resection of the prostate for benign prostatic hyperplasia: a systematic review with meta-analysis of randomized controlled trials.

    Science.gov (United States)

    Zang, Ya-Chen; Deng, Xin-Xi; Yang, Dong-Rong; Xue, Bo-Xin; Xu, Li-Jun; Liu, Xiao-Long; Zhou, Yi-Bin; Shan, Yu-Xi

    2016-02-01

    The aim of this study is to assess the overall efficacy and safety of photoselective vaporization of the prostate (PVP) with GreenLight 120-W laser versus transurethral resection of the prostate (TURP) for treating patients of benign prostate hyperplasia (BPH) with lower urinary tract symptoms (LUTS). We performed a literature search of The Cochrane Library and the electronic databases, including Embase, Medline, and Web of Science. Manual searches were conducted of the conference proceedings, including European Association of Urology and American Urological Association (2007 to 2012). Outcomes reviewed included clinical baseline characteristics, perioperative data, complications, and postoperative functional results, such as postvoid residual (PVR), international prostate symptom score (IPSS), quality of life (QoL), and maximum flow rate (Qmax). Six randomized controlled trials (RCTs) were enrolled. Three hundred and forty-seven patients undergone 120-W PVP, and 350 patients were treated with TURP in the RCTs. There were no significant differences for clinical characteristics in these trials. In perioperative data, catheterization time and length of hospital stay were shorter in the PVP group. However, the operation time was shorter in the TURP group. Capsular perforation, blood transfusion, clot retention, and macroscopic hematuria were markedly less likely in PVP-treated subjects. The other complications between PVP and TURP did not demonstrate a statistic difference. There were no significant differences in QoL, PVR, IPSS, and Qmax in the 1, 3, 6, 12, and 24 months of postoperative follow-up. There was no significant difference at postoperation follow-up of functional outcomes including IPSS, PVR, Qmax, and QoL between the TURP-treated subjects and PVP-treated subjects. Owing to a shorter catheterization time, reduced hospital duration and less complication, PVP could be used as an alternative and a promising minimal invasive surgical procedure for the

  3. Electrospinning of multicomponent ultrathin fibrous nonwovens for semi-occlusive wound dressings.

    Science.gov (United States)

    Hong, Youliang; Li, Yanan; Zhuang, Xiuli; Chen, Xuesi; Jing, Xiabin

    2009-05-01

    This work describes the design and assembly of multifunctional and cost-efficient composite fiber nonwovens as semi-occlusive wound dressings using a simple electrospinning process to incorporate a variety of functional components into an ultrathin fiber. These components include non-hydrophilic poly(L-lactide) (PLLA) as fibrous backbone, hydrophilic poly(vinyl pyrrolidone)-iodine (PVP-I), TiO(2) nanoparticles, zinc chloride as antimicrobial, odor-controlling, and antiphlogistic agents, respectively. The process of synthesis starts with a multicomponent solution of PLLA, PVP, TiO(2) nanoparticles plus zinc chloride, in which TiO(2) nanoparticles are synthesized by in situ hydrolysis of TiO(2) precursors in a PVP solution for the sake of obtaining the particle-uniformly dispersive solution. Subsequent electrospinning generates the corresponding composite fibers. A further iodine vapor treatment to the composite fibers combines iodine with PVP to produce the PVP-I complexes. Experiments indicate that the assembled composite fibers (300-400 nm) possess the ointment-releasing characteristic and the phase-separate, core-sheath structures in which PVP-I residing in fiber surface layer becomes the sheath, and PLLA distributing inside the fiber acts as the core. Based on this design, the structural advantages combining active components endow the assembled composite nonwovens with a variety of functions, especially, the existence of PVP-I, endows the nonwoven with water absorbability, antimicrobial activity, adhesive ability, and transformable characteristic from hydrophilicity to non-hydrophilicity. The multifunctional, cost-efficient, and ointment-releasing characteristics make the multicomponent composite fibrous nonwovens potentially useful in applications such as initial stage of dressing of the cankerous or contaminated wounds.

  4. Effects of fluid flow on elution of hydrophilic modifier from dialysis membrane surfaces.

    Science.gov (United States)

    Matsuda, Masato; Sato, Mika; Sakata, Hiroki; Ogawa, Takahisa; Yamamoto, Ken-ichiro; Yakushiji, Taiji; Fukuda, Makoto; Miyasaka, Takehiro; Sakai, Kiyotaka

    2008-01-01

    When uremic blood flows through dialyzers during hemodialysis, dialysis membrane surfaces are exposed to shear stress and internal filtration, which may affect the surface characteristics of the dialysis membranes. In the present study, we evaluated changes in the characteristics of membrane surfaces caused by shear stress and internal filtration using blood substitutes: water purified by reverse osmosis and 6.7 wt% dextran70 solution. We focused on the levels of a hydrophilic modifier, polyvinylpyrrolidone (PVP), on the membrane surface measured by attenuated total reflectance Fourier transform infrared spectroscopy. Experiments involving 4 h dialysis, 0-144 h shear-stress loading, and 4 h dead-end filtration were performed using polyester-polymer alloy (PEPA) and polysulfone (PS) membranes. After the dialysis experiments with accompanying internal filtration, average PVP retention on the PEPA membrane surface was 93.7% in all areas, whereas that on the PS membrane surface was 98.9% in all areas. After the shear-stress loading experiments, PVP retention on the PEPA membrane surface decreased as shear-stress loading time and the magnitude of shear stress increased. However, with the PS membrane, PVP retention scarcely changed. After the dead-end filtration experiments, PVP retention decreased in all areas for both PEPA and PS membranes, but PVP retention on the PEPA membrane surface was lower than that on the PS membrane surface. PVP on the PEPA membrane surface was eluted by both shear stress and internal filtration, while that on the PS membrane surface was eluted only by internal filtration.

  5. Smooth-surface silver nanowire electrode with high conductivity and transparency on functional layer coated flexible film

    Energy Technology Data Exchange (ETDEWEB)

    Lee, So Hee; Lim, Sooman; Kim, Haekyoung, E-mail: hkkim@ynu.ac.kr

    2015-08-31

    Transparent conductive electrode (TCE) with silver nanowires has been widely studied as an alternative of indium tin oxide for flexible electronic or optical devices such as organic light-emitting diodes, and solar cells. However, it has an issue of surface roughness due to nanowire's intrinsic properties. Here, to achieve a smooth electrode with high conductivity and transmittance on polyethylene terephthalate (PET) substrates, a functional layer of poly(N-vinylpyrrolidone) (PVP) is utilized with a mechanical transfer process. The silver nanowire electrode on PVP-coated PET with low surface roughness of 9 nm exhibits the low sheet resistance of 18 Ω □{sup −1} and high transmittance of 87.6%. It is produced by transferring the silver nanowire electrode spin-coated on the glass to PVP-coated PET using a pressure of 10 MPa for 10 min. Silver nanowire electrode on PVP-coated PET demonstrates the stable sheet resistance of 18 Ω □{sup −1} after the mechanical taping test due to strong adhesion between PVP functional layer and silver nanowires. Smooth TCE with silver nanowires could be proposed as a transparent electrode for flexible electronic or optical devices, which consist of thin electrical active layers on TCE. - Highlights: • Silver nanowire (Ag NWs) transparent electrodes were fabricated on flexible film. • Flexible film was coated with poly N-vinylpyrrolidone (PVP). • PVP layer plays roles as an adhesive layer and matrix in electrode. • Ag NWs electrode exhibited with low surface roughness of 9 nm. • Ag NWs electrode has a low resistance (18 Ω ☐{sup −1}) and high transmittance (87.6%)

  6. Poly(N-vinylpyrrolidone)-block-poly(vinyl acetate) as a drug delivery vehicle for hydrophobic drugs.

    Science.gov (United States)

    Bailly, Nathalie; Thomas, Mark; Klumperman, Bert

    2012-12-10

    Poly((N-vinylpyrrolidone)-block-poly(vinyl acetate)) (PVP-b-PVAc) block copolymers of varying molecular weight and hydrophobic block lengths were synthesized via controlled radical polymerization and investigated as carriers for the solubilization of highly hydrophobic riminophenazine compounds. These compounds have recently been shown to exhibit a strong activity against a variety of cancer types. PVP-b-PVAc self-assembles into polymer vesicles in aqueous media, and the dialysis method was used to load the water-insoluble drug (clofazimine) into these polymer vesicles. The polymer vesicles were characterized by 1H NMR spectroscopy to confirm vesicle formation and the incorporation of the anticancer drugs into the polymer vesicles. Dynamic light scattering was used to determine the particle size and particle size distribution of the drug-loaded vesicles as well as the stability of the vesicles under physiological conditions. The size of the polymer vesicles did not increase upon loading with clofazimine, and the particle size of 180-200 nm and the narrow particle size distribution were maintained. The morphology of the vesicles was examined by transmission electron microscopy. The polymer vesicles had a relatively high drug loading capacity of 20 wt %. In vitro cytotoxicity studies of PVP-b-PVAc and drug-loaded PVP-b-PVAc were performed against MDA-MB-231 multidrug-resistant breast epithelial cancer cells and MCF12A nontumorigenic breast epithelial cells. In vitro experiments demonstrated that the PVP-b-PVAc drug carrier showed no cytotoxicity, which confirms the biocompatibility of the PVP-b-PVAc drug carrier. The results indicate that the present PVP-b-PVAc block copolymer could be a potential candidate as a drug carrier for hydrophobic drugs.

  7. Treatment of Metastatic Spinal Tumors by Percutaneous Vertebroplasty versus Percutaneous Vertebroplasty Combined with Interstitial Implantation of 125I Seeds

    Energy Technology Data Exchange (ETDEWEB)

    Zuozhang Yang; Lin Xie; Yunchao Huang; Hongpu Sun; Pengjie Liu; Zhongxiong Wu (Dept. of Orthopedics, Tumor Hospital of Yunnan Province, Third Affiliated Hospital of Kunming Medical College, Kunming, Yunnan (China)). e-mail. yangzuozhang@163.com; Dakuan Yang (Second Affiliated Hospital of Kunming Medical College, Kunming Yunnan (China)); Yuqing Sun (Dept. of Orthopedic Oncology, Beijing Jishuitan Hospital, Beijing (China))

    2009-12-15

    Background: As the most frequent bone metastasis, spinal metastases cause severe pain and damage to vertebral bodies such as spinal osteolytic destruction and compression fractures. To avoid the trauma and complications of open surgery, a minimally invasive procedure, percutaneous vertebroplasty (PVP), has recently been developed to treat metastatic spinal tumors. Purpose: To analyze the treatment outcomes of metastatic spinal tumors by percutaneous vertebroplasty (PVP) alone or PVP combined with interstitial implantation of 125I seeds. Material and Methods: 80 patients with metastatic spinal tumors were randomized to receive PVP alone (40 cases) or PVP combined with 125I seed implantation (40 cases). Digital subtraction angiography (DSA)-guided vertebroplasty was performed under local anesthesia, and acrylic bone cement was injected into the vertebra through a bone trocar to the center of the lesion, with or without simultaneous interstitial implantation of 125I seeds. Results: At 6-month follow-up, PVP combined with 125I seed implantation resulted in zero cases with complete relief (CR), 36 with partial relief (PR), four with no changes (NC), and zero with progression of disease (PD), while PVP alone without seed implantation resulted in 0 CR, 31 PR, 7 NC, and 2 PD. While the combined-treatment group and the single-PVP group showed overall clinical benefit rates without significant difference (100% and 95.0%, respectively), their visual analogue pain scales (VAS; 2.26+-1.05 and 5.41+-0.94, respectively) and Karnofsky performance scores (KPS; 92.5+-7.1 and 87.7+-7.3, respectively) were significantly different after treatment (P = 0.028 and P = 0.009, respectively). Patients in both groups had 1-year follow-up, and the mean time to tumor progression (TTP) was 9.0 and 8.9 months, respectively (not significant). Conclusion: PVP is a minimally invasive procedure with small wounds and minor complications. It is effective in the alleviation of pain in metastatic spinal

  8. A rapid approach for measuring silver nanoparticle concentration and dissolution in seawater by UV-Vis.

    Science.gov (United States)

    Sikder, Mithun; Lead, Jamie R; Chandler, G Thomas; Baalousha, Mohammed

    2017-04-12

    Detection and quantification of engineered nanoparticles (NPs) in environmental systems is challenging and requires sophisticated analytical equipment. Furthermore, dissolution is an important environmental transformation process for silver nanoparticles (AgNPs) which affects the size, speciation and concentration of AgNPs in natural water systems. Herein, we present a simple approach for the detection, quantification and measurement of dissolution of PVP-coated AgNPs (PVP-AgNPs) based on monitoring their optical properties (extinction spectra) using UV-vis spectroscopy. The dependence of PVP-AgNPs extinction coefficient (ɛ) and maximum absorbance wavelength (λmax) on NP size was experimentally determined. The concentration, size, and extinction spectra of PVP-AgNPs were characterized during dissolution in 30ppt synthetic seawater. AgNPs concentration was determined as the difference between the total and dissolved Ag concentrations measured by inductively coupled plasma-mass spectroscopy (ICP-MS); extinction spectra of PVP-AgNPs were monitored by UV-vis; and size evolution was monitored by atomic force microscopy (AFM) over a period of 96h. Empirical equations for the dependence of maximum absorbance wavelength (λmax) and extinction coefficient (ɛ) on NP size were derived. These empirical formulas were then used to calculate the size and concentration of PVP-AgNPs, and dissolved Ag concentration released from PVP-AgNPs in synthetic seawater at variable particle concentrations (i.e. 25-1500μgL(-1)) and in natural seawater at particle concentration of 100μgL(-1). These results suggest that UV-vis can be used as an easy and quick approach for detection and quantification (size and concentration) of sterically stabilized PVP-AgNPs from their extinction spectra. This approach can also be used to monitor the release of Ag from PVP-AgNPs and the concurrent NP size change. Finally, in seawater, AgNPs dissolve faster and to a higher extent with the decrease in NP

  9. In vivo potency and efficacy of the novel cathinone α-pyrrolidinopentiophenone and 3,4-methylenedioxypyrovalerone: Self-administration and locomotor stimulation in male rats

    Science.gov (United States)

    Aarde, Shawn M.; Creehan, Kevin M.; Vandewater, Sophia A.; Dickerson, Tobin J.; Taffe, Michael A.

    2015-01-01

    Rationale Numerous substituted cathinone drugs have appeared in recreational use. This variety is often a response to legal actions; the scheduling of 3,4-methylenedioxypyrovalerone (MDPV; “bath salts”) in the U.S.A. was followed by the appearance of the closely related drug α-pyrrolidinopentiophenone (alpha-PVP; “flakka”). Objectives To directly compare the efficacy and potency of alpha-PVP with that of MDPV. Methods Groups of male Wistar rats were trained in the intravenous self-administration (IVSA) alpha-PVP or MDPV under a fixed-ratio 1 schedule of reinforcement. An additional group was examined for locomotor and body temperature responses to non-contingent administration of MDVP or alpha-PVP (1.0, 5.6, 10.0 mg/kg, i.p.). Results Acquisition of alpha-PVP (0.1 mg/kg/infusion) IVSA resulted in low, yet consistent drug intake and excellent discrimination for the drug-paired lever. Dose-substitution (0.05-0.25 mg/kg/infusion) under a fixed-ratio 1 schedule confirmed potency is similar to MDPV in prior studies. In direct comparison to MDPV (0.05 mg/kg/infusion), rats trained on alpha-PVP (0.05 mg/kg/infusion) responded for more infusions but demonstrated similar drug-lever discrimination by the end of acquisition. However, the dose-response (0.018-0.56 mg/kg/inf) functions of these drugs under a progressive-ratio schedule of reinforcement reflected identical efficacy and potency. Peak locomotor responses to MDPV or alpha-PVP were observed after the 1.0 mg/kg, i.p. dose and lasted ~2 hours. Modest body temperature decreases were of similar magnitude (~0.75°C) for each compound. Conclusions The potency and efficacy of MDPV and alpha-PVP were very similar across multiple assays, predicting that the abuse liability of alpha-PVP will be significant and similar to that of MDPV. PMID:25925780

  10. In vivo potency and efficacy of the novel cathinone α-pyrrolidinopentiophenone and 3,4-methylenedioxypyrovalerone: self-administration and locomotor stimulation in male rats.

    Science.gov (United States)

    Aarde, Shawn M; Creehan, Kevin M; Vandewater, Sophia A; Dickerson, Tobin J; Taffe, Michael A

    2015-08-01

    Numerous substituted cathinone drugs have appeared in recreational use. This variety is often a response to legal actions; the scheduling of 3,4-methylenedioxypyrovalerone (MDPV; "bath salts") in the USA was followed by the appearance of the closely related drug α-pyrrolidinopentiophenone (alpha-PVP; "flakka"). This study aimed to directly compare the efficacy and potency of alpha-PVP with that of MDPV. Groups of male Wistar rats were trained in the intravenous self-administration (IVSA) alpha-PVP or MDPV under a fixed-ratio 1 schedule of reinforcement. An additional group was examined for locomotor and body temperature responses to noncontingent administration of MDVP or alpha-PVP (1.0, 5.6, and 10.0 mg/kg, i.p.). Acquisition of alpha-PVP (0.1 mg/kg/infusion) IVSA resulted in low, yet consistent drug intake and excellent discrimination for the drug-paired lever. Dose substitution (0.05-0.25 mg/kg/infusion) under a fixed-ratio 1 schedule confirmed potency was similar to MDPV in prior studies. In direct comparison to MDPV (0.05 mg/kg/infusion), rats trained on alpha-PVP (0.05 mg/kg/infusion) responded for more infusions but demonstrated similar drug-lever discrimination by the end of acquisition. However, the dose-response (0.018-0.56 mg/kg/infusion) functions of these drugs under a progressive-ratio schedule of reinforcement reflected identical efficacy and potency. Peak locomotor responses to MDPV or alpha-PVP were observed after the 1.0 mg/kg, i.p. dose and lasted ∼2 h. Modest body temperature decreases were of similar magnitude (∼0.75 °C) for each compound. The potency and efficacy of MDPV and alpha-PVP were very similar across multiple assays, predicting that the abuse liability of alpha-PVP will be significant and similar to that of MDPV.

  11. Synthesis of Sensitive Polyelectrolyte Complex Nanoparticles and the Controlled Release of 5-FU%敏感性聚电解质纳米粒子的制备及对5-FU的控制释放

    Institute of Scientific and Technical Information of China (English)

    戚旻熠; 于娜娜; 李桂英

    2014-01-01

    以壳聚糖( CS)和海藻酸钠( SA)为原料,通过接枝共聚制备了壳聚糖接枝聚N-乙烯基吡烙烷酮( CS-g-PVP)和海藻酸钠接枝聚N-乙烯基吡烙烷酮(SA-g-PVP),然后利用静电自组装得到了pH敏感性聚电解质纳米粒子,研究了纳米粒子对5-氟尿嘧啶的负载及释放性能的影响。傅立叶红外光谱验证了聚合物的结构。当CS-g-PVP与SA-g-PVP体积比为3∶7时,形成的纳米粒子结构最稳定。透射电镜表明纳米粒子具有较规则的球形结构,尺寸在30~50 nm左右。聚电解质纳米粒子对5-FU表现出较高的负载能力,环境pH值和离子强度等因素对5-FU的释放有影响。%pH-sensitive polyelectrolyte complex nanoparticles assembled from chitosan-graft-poly ( 1-vinyl-2-pyrrolidone) (CS-g-PVP) and sodium alginate-graft-poly(1-vinyl-2-pyrrolidone) (SA-g-PVP) were prepared for entrapment and release of 5-fluorouracil ( 5-FU ) . The structure of polymers was determined by fourier-transformed infrared spectroscopy ( FTIR) . The highly aggregated nanoparticle was formed at the weight ratio of CS-g-PVP and SA-g-PVP is 3∶7 with a core formed from positively charged CS and negatively charged SA and a shell formed from hydrophilic PVP. The size and morphology of the nanoparticles was observed by transmis-sion electron microscopy ( TEM) . The dried particles gave the normally spheres with an average diameter of 30~50 nm. The CS-g-PVP/SA-g-PVP polyelectrolyte complex nanoparticles exhibited high drug loading content and encapsulation efficiency for 5-FU. Decreasing pH to weak acid or increasing ionic strength of nanoparticles solution,a sustained and controlled drug release was observed due to the deformation of nanoparticles.

  12. Inductive effect of poly(vinyl pyrrolidone) on morphology and photocatalytic performance of Bi{sub 2}WO{sub 6}

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Qiang; Chen, Jinxing; Xie, Yunyun; Wang, Mozhen; Ge, Xuewu, E-mail: xwge@ustc.edu.cn

    2016-04-15

    Graphical abstract: - Highlights: • PVP molecular chains will induce the assembly of the primary Bi{sub 2}WO{sub 6} nanosheets. • The assembly of primary Bi{sub 2}WO{sub 6} nanosheets forms various 3D topological structure. • Sheet-like, flower-like, red-blood-cell-like and square-pillar-like Bi{sub 2}WO{sub 6} were formed. • Bi{sub 2}WO{sub 6} formed at low concentration or molecular weight of PVP has better activity. - Abstract: Bi{sub 2}WO{sub 6} has great potential applications in the field of photocatalyst due to its excellent visible-light photocatalytic performance. This work studied the detailed morphological evolution of Bi{sub 2}WO{sub 6} particles synthesized in a simple hydrothermal system induced by the stabilizer poly(vinyl pyrrolidone) (PVP). The XRD and HRTEM results show PVP would not change the crystal structure of Bi{sub 2}WO{sub 6}, but the distribution of PVP on the initially formed Bi{sub 2}WO{sub 6} nanosheets will induce the crystal growth, resulting in a distinct morphology evolution of Bi{sub 2}WO{sub 6} with the increase of the concentration of PVP. At the same time, with the increase of the molecular weight of PVP, the morphology of Bi{sub 2}WO{sub 6} varied from simple sheet-like (S-BWO) to some complicated morphology, such as flower-like (F-BWO), red blood cell-like (B-BWO), and square-pillar-like (SP-BWO). The photocatalytic performances of Bi{sub 2}WO{sub 6} with various morphologies on the decomposition of RhB under visible light irradiation reveal that S-BWO has the best photocatalytic performance, while SP-BWO has the worst. This work not only gives the explanation of the inductive effect of PVP molecular chains on the morphological formation of Bi{sub 2}WO{sub 6} particles, but also provides the controllable way to the preparation of Bi{sub 2}WO{sub 6} with various morphologies taking advantage of the stabilizer PVP.

  13. Formation of core-shell-structured Zn2SnO4-carbon microspheres with superior electrochemical properties by one-pot spray pyrolysis.

    Science.gov (United States)

    Hong, Young Jun; Kang, Yun Chan

    2015-01-14

    Core-shell structured Zn2SnO4-carbon microspheres with different carbon contents are prepared by one-pot spray pyrolysis without any further heating process. A Zn2SnO4-carbon composite microsphere is prepared from one droplet containing Zn and Sn salts and polyvinylpyrrolidone (PVP). Melted PVP moves to the outside of the composite microsphere during the drying stage of the droplet. In addition, melting of the phase separated metal salts forms the dense core. Carbonization of the phase separated PVP forms the textured and porous thick carbon shell. The discharge capacities of the core-shell structured Zn2SnO4-carbon microspheres for the 2(nd) and 120(th) cycles at a current density of 1 A g(-1) are 864 and 770 mA h g(-1), respectively. However, the discharge capacities of the bare Zn2SnO4 microspheres prepared by the same process without PVP for the 2(nd) and 120(th) cycles are 1106 and 81 mA h g(-1), respectively. The stable and reversible discharge capacities of the Zn2SnO4-carbon composite microspheres prepared from the spray solution with 15 g PVP decrease from 894 to 528 mA h g(-1) as current density increases from 0.5 to 5 A g(-1).

  14. Relationship between personality disorder functioning styles and the emotional states in bipolar I and II disorders.

    Directory of Open Access Journals (Sweden)

    Jiashu Yao

    Full Text Available Bipolar disorder types I (BD I and II (BD II behave differently in clinical manifestations, normal personality traits, responses to pharmacotherapies, biochemical backgrounds and neuroimaging activations. How the varied emotional states of BD I and II are related to the comorbid personality disorders remains to be settled.We therefore administered the Plutchick - van Praag Depression Inventory (PVP, the Mood Disorder Questionnaire (MDQ, the Hypomanic Checklist-32 (HCL-32, and the Parker Personality Measure (PERM in 37 patients with BD I, 34 BD II, and in 76 healthy volunteers.Compared to the healthy volunteers, patients with BD I and II scored higher on some PERM styles, PVP, MDQ and HCL-32 scales. In BD I, the PERM Borderline style predicted the PVP scale; and Antisocial predicted HCL-32. In BD II, Borderline, Dependent, Paranoid (- and Schizoid (- predicted PVP; Borderline predicted MDQ; Passive-Aggressive and Schizoid (- predicted HCL-32. In controls, Borderline and Narcissistic (- predicted PVP; Borderline and Dependent (- predicted MDQ.Besides confirming the different predictability of the 11 functioning styles of personality disorder to BD I and II, we found that the prediction was more common in BD II, which might underlie its higher risk of suicide and poorer treatment outcome.

  15. Effect of tannin-binding agents (polyethylene glycol and polyvinylpyrrolidone) supplementation on in vitro gas production kinetics of some grape yield byproducts.

    Science.gov (United States)

    Besharati, Maghsoud; Taghizadeh, Akbar

    2011-01-01

    The effects of polyethylene glycol (PEG) and polyvinylpyrrolidone (PVP) on in vitro gas production characteristics, organic matter digestibility (OMD), and metabolizable energy (ME) contents of some grape yield byproducts were investigated. The gas production was recorded after 2, 4, 6, 8, 12, 16, 24, 36, and 48 h of incubation. The gas production profiles in triplicate fitted with equation Y = A (1 - e(-ct)). The data was analyzed using completely randomized design. Total phenol (TP) and total tannin (TT) contents were highest for raisin waste (RW). The TP content (g/kg DM) ranged from 30.1 in grape pomace (GP) to 96.3 in RW, which also had the higher TT (72.1 g/kg DM). The potential gas production (a + b) of DGB, GP, and RW were 239.43, 263.49, and 208.22 mL/g DM, respectively. In the absence of PEG and PVP, rate constant of gas production (c) for GP was highest among the feedstuffs (0.1073 mL/h), but in presence of PEG or PVP, RW had highest fraction (c) among the feedstuffs. Addition of PEG and PVP inactivated effects of tannins and increased gas production, ME, NE1, OMD, and VFA in grape yield byproducts. Addition of PEG and PVP could overcome adverse effects of tannins on nutrient availability as indicated by gas production parameters.

  16. Electrical conductivity studies on Ammonium bromide incorporated with Zwitterionic polymer blend electrolyte for battery application

    Science.gov (United States)

    Parameswaran, V.; Nallamuthu, N.; Devendran, P.; Nagarajan, E. R.; Manikandan, A.

    2017-06-01

    Solid polymer blend electrolytes are widely studied due to their extensive applications particularly in electrochemical devices. Blending polymer makes the thermal stability, higher mechanical strength and inorganic salt provide ionic charge carrier to enhance the conductivity. In these studies, 50% polyvinyl alcohol (PVA), 50% poly (N-vinyl pyrrolidone) (PVP) and 2.5% L-Asparagine mixed with different ratio of the Ammonium bromide (NH4Br), have been synthesized using solution casting technique. The prepared PVA/PVP/L-Asparagine/doped-NH4Br polymer blend electrolyte films have been characterized by various analytical methods such as FT-IR, XRD, impedance spectroscopy, TG-DSC and scanning electron microscopy. FT-IR, XRD and TG/DSC analysis revealed the structural and thermal behavior of the complex formation between PVA/PVP/L-Asparagine/doped-NH4Br. The ionic conductivity and the dielectric properties of PVA/PVP/L-Asparagine/doped-NH4Br polymer blend electrolyte films were examined using impedance analysis. The highest ionic conductivity was found to be 2.34×10-4 S cm-1 for the m.wt. composition of 50%PVA:50%PVP:2.5%L-Asparagine:doped 0.15 g NH4Br at ambient temperature. Solid state proton battery is fabricated and the observed open circuit voltage is 1.1 V and its performance has been studied.

  17. Preparation of active 3D film patches via aligned fiber electrohydrodynamic (EHD) printing

    Science.gov (United States)

    Wang, Jun-Chuan; Zheng, Hongxia; Chang, Ming-Wei; Ahmad, Zeeshan; Li, Jing-Song

    2017-03-01

    The design, preparation and application of three-dimensional (3D) printed structures have gained appreciable interest in recent times, particularly for drug dosage development. In this study, the electrohydrodynamic (EHD) printing technique was developed to fabricate aligned-fiber antibiotic (tetracycline hydrochloride, TE-HCL) patches using polycaprolactone (PCL), polyvinyl pyrrolidone (PVP) and their composite system (PVP-PCL). Drug loaded 3D patches possessed perfectly aligned fibers giving rise to fibrous strut orientation, variable inter-strut pore size and controlled film width (via layering). The effect of operating parameters on fiber deposition and alignment were explored, and the impact of the film structure, composition and drug loading was evaluated. FTIR demonstrated successful TE-HCL encapsulation in aligned fibers. Patches prepared using PVP and TE-HCL displayed enhanced hydrophobicity. Tensile tests exhibited changes to mechanical properties arising from additive effects. Release of antibiotic from PCL-PVP dosage forms was shown over 5 days and was slower compared to pure PCL or PVP. The printed patch void size also influenced antibiotic release behavior. The EHDA printing technique provides an exciting opportunity to tailor dosage forms in a single-step with minimal excipients and operations. These developments are crucial to meet demands where dosage forms cannot be manufactured rapidly or when a personalized approach is required.

  18. Clinical effects of conjunctival sac flushing using different concentration of povidoneiodine on corneal epithelium before cataract surgeries

    Directory of Open Access Journals (Sweden)

    Xue-Lian Gu

    2015-10-01

    Full Text Available AIM:To determine the most optimal concentration of the safe usage of povidone-iodine(PVP-Iin the flushing to disinfect the conjunctive sac before cataract surgeries, in order to provide a scientific basis for clinical eye surgery work.METHODS:Sixty-two patients with phacoemulsification and intraocular lens implantation in our hospital from October 2012 to October 2014 were randomly divided into 0.25g/L PVP-I group(Ⅰand 5g/L PVP-I group(Ⅱ. Sterilizing effect and the complications postoperative were analyzed.RESULTS:The sterilizing effects of the two groups after flushing conjunctiva sac using different concentrations of PVP-I were both remarkable, but the difference between the two groups was not statistically significant(P>0.05. No endophthalmitis occurred in the two groups. Observing the corneal condition after rinsing, no severe conjunctival hyperemia, corneal edema and other serious complications occurred. There was slightly punctate corneal epithelial shedding in groupⅡ, and the difference was statistically significant(PPCONCLUSION:Using 0.25g/L PVP-I in the conjunctiva sac rinsing before surgeries can inhibit the growth of bacteria in the conjunctival sac, reduce the impact on the corneal epithelium thereby reducing the incidence of postoperative complications and the positive rate of bacterial culture, increasing the comfort degree of patients, bringing a better area for the surgeries.

  19. Polymerization of Vinylpyrrolidone to Form a Neutral Coating on Anionic Nanomaterials in Aqueous Suspension for Rapid Sedimentation

    Directory of Open Access Journals (Sweden)

    Edward P. C. Lai

    2014-05-01

    Full Text Available Nanomaterials in water present an array of identifiable potential hazards to ecological and human health. There is no general consensus about the influence of anionic or cationic charge on the toxicity of nanomaterials on environmental ecology. One challenge is the limited number of scalable technologies available for the removal of charged nanomaterials from water. A new method based on polymer coating has been developed in our laboratory for rapid sedimentation of nanomaterials in aqueous suspension. Using colloidal silica as a model inorganic oxide, coating of polyvinylpyrrolidone (PVP around the SiO2 nanoparticles produced SiO2@PVP particles, as indicated by a linear increase of nephelometric turbidity. Purification of the water sample was afforded by total sedimentation of SiO2@PVP particles when left for 24 h. Characterization by capillary electrophoresis (CE revealed nearly zero ionic charge on the particles. Further coating of polydopamine (PDA around those particles in aqueous suspension produced an intense dark color due to the formation of SiO2@PVP@PDA. The SiO2@PVP@PDA peak appeared at a characteristic migration time of 4.2 min that allowed for quantitative CE-UV analysis to determine the original SiO2 concentration with enhanced sensitivity and without any ambiguous identity.

  20. Polyvinylpyrrolidone-Capped Silver Nanoparticle Inhibits Infection of Carbapenem-Resistant Strain of Acinetobacter baumannii in the Human Pulmonary Epithelial Cell

    Directory of Open Access Journals (Sweden)

    Vishvanath Tiwari

    2017-08-01

    Full Text Available Acinetobacter baumannii, an opportunistic ESKAPE pathogen, causes respiratory and urinary tract infections. Its prevalence increases gradually in the clinical setup. Pathogenicity of Acinetobacter is significantly influenced by its ability to infect and survive in human pulmonary cells. Therefore, it is important to study the infection of A. baumannii in human pulmonary host cell (A-549, monitoring surface interacting and internalized bacteria. It was found that during infection of A. baumannii, about 40% bacteria adhered to A-549, whereas 20% got internalized inside pulmonary cell and induces threefold increase in the reactive oxygen species production. We have synthesized polyvinylpyrrolidone (PVP-capped AgNPs using chemical methods and tested its efficacy against carbapenem-resistant strain of A. baumannii. PVP-capped silver nanoparticles (PVP-AgNPs (30 µM have shown antibacterial activity against carbapenem-resistant strain of A. baumannii and this concentration does not have any cytotoxic effect on the human pulmonary cell line (IC50 is 130 µM. Similarly, PVP-AgNPs treatment decreases 80% viability of intracellular bacteria, decreases adherence of A. baumannii to A-549 (40 to 2.2%, and decreases intracellular concentration (20 to 1.3% of A. baumannii. This concludes that PVP-AgNPs can be developed as a substitute for carbapenem to control the infection caused by carbapenem-resistant A. baumannii.

  1. Preparation and stabilization of heparin/gelatin complex coacervate microcapsules.

    Science.gov (United States)

    Tsung, M; Burgess, D J

    1997-05-01

    The aims of this study are to optimize conditions for the preparation, stabilization, and harvesting of heparin/gelatin microcapsules prepared by complex coacervation. Microelectrophoresis and dry coacervate weight were used to determine the optimum conditions of pH and ionic strength for maximum heparin/gelatin coacervate yield. Heparin/gelatin microcapsules were formed by complex coacervation in the presence and absence of poly(1-vinyl-2-pyrrolidone) (PVP), which was used as a stabilizer. The microcapsules were collected using a spray-drying technique. Microcapsule particle size was analyzed using an AccuSizer optical sizer. Optimized conditions for maximum coacervate yield were pH 2.6, ionic strength 10 mM, and a 1:2 heparin/gelatin A ratio. PVP stabilized the heparin/gelatin coacervate droplets and reduced droplet aggregation during spray-drying. The mean particle diameter of the spray-dried coacervate droplets was lower in the presence of PVP and was unaffected by PVP concentration (in the range 0.5-2.0% w/w). Heparin/gelatin microcapsules, prepared under conditions optimized for maximum coacervate yield, were stabilized without the use of chemical cross-linking agents. Stabilization was achieved by a combination of the addition of PVP and spray-drying.

  2. Unexpected solvent impact in the crystallinity of praziquantel/poly(vinylpyrrolidone) formulations. A solubility, DSC and solid-state NMR study.

    Science.gov (United States)

    Costa, Emanuel D; Priotti, Josefina; Orlandi, Silvina; Leonardi, Darío; Lamas, María C; Nunes, Teresa G; Diogo, Hermínio P; Salomon, Claudio J; Ferreira, M João

    2016-09-25

    The saturation solubility of PVP:PZQ physical mixtures (PMs) and solid dispersions (SDs) prepared from ethanol (E/E) or ethanol/water (E/W) by the solvent evaporation method at 1:1, 2:1 and 3:1 ratio (w/w) was determined. The presence of PVP improves the solubility of PZQ (0.31±0.01mg/mL). A maximum of 1.29±0.03mg/mL of PZQ in solution was achieved for the 3:1 SD (E/E). The amount of PZQ in solution depends on the amount of polymer and on the preparation method. Solid-state NMR (ssNMR) and DSC were used to understand this behavior. Results show that PMs are a mixture of crystalline PZQ with the polymer, while SDs show different degrees of drug amorphization depending on the solvent used. For E/W SDs, PZQ exists in amorphous and crystalline states, with no clear correlation between the amount of crystalline PZQ and the amount of PVP. For E/E SDs, formulations with a higher percentage of PZQ are amorphous with the components miscible in domains larger than 3nm ((1)H ssNMR relaxation measurements). Albeit its higher saturation solubility, the 3:1 E/E PVP:PZQ sample has a significant crystalline content, probably due to the water introduced by the polymer. High PVP content and small crystal size account for this result.

  3. Controllable synthesis of α-sulfur spheres with hierarchical nanostructures for efficient visible-light-driven photocatalytic ability

    Energy Technology Data Exchange (ETDEWEB)

    Dang, Xueming; Zhang, Xiufang, E-mail: zhangxf@dlpu.edu.cn; Zhang, Weiqiang; Dong, Xiaoli; Wang, Guowen; Ma, Hongchao

    2015-08-30

    Highlights: • α-Sulfur spheres with hierarchical nanostructures are controllably produced. • Addition quantity of PVP affects photocatalytic ability of α-sulfur. • The enhanced photocatalytic ability of α-sulfur hierarchical sphere is found. - Abstract: Visible-light-active α-sulfur spheres with hierarchical nanostructures were fabricated by simple solution-phase synthesis with PVP as the template for enhanced photocatalytic ability. The α-sulfur hierarchical spheres with an ultrahigh specific surface area can controllable synthesized by changing the addition quantity of PVP. The obtained products are systematically studied by X-ray diffraction (XRD), Fourier transform infrared (FT-IR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), UV–vis absorption spectroscopy (DRS), Fluorescence (FL) and Brunauer-Emmett-Teller (BET). The photocatalytic activity of the as-prepared samples is evaluated by photocatalytic degradation of Rhodamine B (RhB) aqueous solution under visible light illumination. The results indicate that the morphology, specific surface area, photo absorbance ability, the separation efficiency of photogenerated carriers and the reactant adsorption performance can be controlled by varying the addition quantity of PVP. When 200 mg PVP is added, α-sulfur hierarchical spheres with uniform particle size about 1 μm and ultrahigh specific surface area of 67.1 m{sup 2}/g is obtained, and its photocatalytic activity reaches a maximum value, which can be attributed to the combined effects of photo absorbance ability, the separation efficiency of photogenerated carriers and the reactant adsorption performance.

  4. Structure-performance-fouling studies of polysulfone microfiltration hollow fibre membranes

    Indian Academy of Sciences (India)

    P S Singh; K Parashuram; S Maurya; P Ray; A V R Reddy

    2012-10-01

    Hollow fibre microfiltration membranes were prepared by solution spinning process using polymer dope containing different amounts of polysulfone (PS), polyvinylpyrollidone (PVP) and ,-dimethylformamide (DMF). Spinning dope having PS: PVP: DMF (w/w) of 15: 5: 80, 15: 7: 78 and 17: 8: 75 were used for spinning to obtain hollow fibres having different dimensions (outer and inner diameters) and pore characteristics. Relatively high water permeability was observed for hollow fibre membrane spun from 15 wt. % solution than 17 wt. % PS solution having the same PVP/PS ratio of 0.47. Decrease of the PVP/PS ratio to 0.33 in the dope solution of 15 wt.%PS solution produced hollow fibre membrane with lower flux. By changing the spinning parameters, fibre with different dimensions were obtained without a significant change in microstructural morphology. The flux decline due to fouling for the permeation of PEO/BSA solution was maximum for the hollow fibre membrane obtained from 15 wt. % PS solution while a steady flux with slight fouling was observed for the hollow fibre membrane obtained from 17 wt. %PS solution, when the PVP/PS ratio was 0.47.

  5. Correlation between central venous pressure and peripheral venous pressure with passive leg raise in patients on mechanical ventilation

    Directory of Open Access Journals (Sweden)

    Dharmendra Kumar

    2015-01-01

    Full Text Available Background: Central venous pressure (CVP assesses the volume status of patients. However, this technique is not without complications. We, therefore, measured peripheral venous pressure (PVP to see whether it can replace CVP. Aims: To evaluate the correlation and agreement between CVP and PVP after passive leg raise (PLR in critically ill patients on mechanical ventilation. Setting and Design: Prospective observational study in Intensive Care Unit. Methods: Fifty critically ill patients on mechanical ventilation were included in the study. CVP and PVP measurements were taken using a water column manometer. Measurements were taken in the supine position and subsequently after a PLR of 45°. Statistical Analysis: Pearson′s correlation and Bland-Altman′s analysis. Results: This study showed a fair correlation between CVP and PVP after a PLR of 45° (correlation coefficient, r = 0.479; P = 0.0004 when the CVP was 10 cmH 2 O. Bland-Altman analysis showed 95% limits of agreement to be −2.912-9.472. Conclusion: PVP can replace CVP for guiding fluid therapy in critically ill patients.

  6. Safety of greenlight photoselective vaporisation of prostate in lower urinary tract symptoms due to benign prostatic hyperplasia in patients using anticoagulants due to cardiovascular comorbidities

    Directory of Open Access Journals (Sweden)

    Basri Cakiroglu

    2015-07-01

    Full Text Available Lasers have been used in the management of benign prostatic hyperplasia for the last two decades. To be comparable, they should reduce or avoid the immediate and long-term complications of transurethral resection of the prostate (TURP or open prostatectomy (OP, especially bleeding and need for blood transfusion. Although Holmium laser treatment of the prostate was compared frequently in terms of cardiovascular safety with TURP or OP, photoselective vaporisation of the prostate (PVP was not largely evaluated. In this article we analyzed the current literature to see if there is convincing data to support the observation of some authors that use of PVP is associated with increased safety in patients on anticoagulants with cardiovascular comorbidities. With this purpose a Medline search between January 2004 to March 2013 was performed using evidence obtained from randomised trials, well-designed controlled studies without randomisation, individual cohort studies, individual case control studies and case reports Results: In the last 10 years, several case-control and cohort studies have demonstrated the efficacy of PVP as well as its safety in patients with cardiovascular comorbidities using anticoagulants. The results confirmed the overall lower perioperative and postoperative morbidity of PVP, whereas the efficacy was comparable to TURP in the short term, despite a higher reoperation rate. Conclusion: Although it is still developing, PVP with KTP or LBO seems to be a promising alternative to both TURP and OP in terms of cardiovascular safety and in patients using anticoagulants.

  7. In vitro antimicrobial activity of solution blow spun poly(lactic acid)/polyvinylpyrrolidone nanofibers loaded with Copaiba (Copaifera sp.) oil

    Energy Technology Data Exchange (ETDEWEB)

    Bonan, Roberta F. [Departamento de Engenharia de Materiais (DEMAT), Universidade Federal da Paraíba (UFPB), Cidade Universitária, 58.051-900 João Pessoa, PB (Brazil); Centro de Ciências da Saúde (CCS), Universidade Federal da Paraíba (UFPB), Cidade Universitária, 58.051-900 João Pessoa, PB (Brazil); Bonan, Paulo R.F.; Batista, André U.D.; Sampaio, Fábio C.; Albuquerque, Allan J.R. [Centro de Ciências da Saúde (CCS), Universidade Federal da Paraíba (UFPB), Cidade Universitária, 58.051-900 João Pessoa, PB (Brazil); Moraes, Maria C.B. [Embrapa Recursos Genéticos e Biotecnologia, Parque Estação Ecológica, W/5 Norte (Final) Cenargen (Laboratório de Semioquímicos) ASA NORTE, 70770900 Brasília, DF (Brazil); Mattoso, Luiz H.C. [Laboratório Nacional de Nanotecnologia para o Agronegócio (LNNA), Embrapa Instrumentação Agropecuária (CNPDIA), Rua XV de Novembro, 1452, Centro, 13.560, 970 São Carlos, SP (Brazil); Glenn, Gregory M. [United States Department of Agriculture (USDA), Western Regional Research Center (WRRC), Bioproduct Chemistry and Engineering - BCE, Albany, CA 94710 (United States); and others

    2015-03-01

    In this study poly(lactic acid) (PLA) and polyvinylpyrrolidone (PVP) micro- and nanofiber mats loaded with Copaiba (Copaifera sp.) oil were produced by solution blow spinning (SBS). The Copaiba (Copaifera sp.) oil was characterized by gas chromatography (GC). Neat PLA and four PLA/PVP blends containing 20% (wt.%) oil were spun and characterized by scanning electron microscopy (SEM) and by studying the surface contact angle, in vitro release rate, and antimicrobial activity. All compositions evaluated were able to produce continuous and smooth fibers by SBS. The addition of PVP increased fiber diameter, and decreased the surface contact angle. GC analysis demonstrated that the main component of the Copaiba oil was β-caryophyllene, a known antimicrobial agent. In vitro release tests of Copaiba oil volatiles demonstrated a higher release rate in fibers containing PVP. Fiber mats made from blends containing higher amounts of PVP had greater antimicrobial action against Staphylococcus aureus. The results confirm the potential of the fiber mats for use in controlled drug release and could lead to promising applications in the biomedical field. - Highlights: • An efficient method for production of antimicrobial nanofiber mats using solution blow spinning was reported. • Nanofiber mats containing Copaiba oil were efficient against Staphylococcus aureus. • Nanofiber composition changed morphological properties and antimicrobial action.

  8. Development and Evaluation of Mouth Dissolving Films of Amlodipine Besylate for Enhanced Therapeutic Efficacy

    Directory of Open Access Journals (Sweden)

    K. M. Maheswari

    2014-01-01

    Full Text Available The present investigation was undertaken with an objective of formulating mouth dissolving films (MDFs of Amlodipine Besylate (AMLO to enhance convenience and compliance of the elderly and pediatric patients for better therapeutic efficacy. Film formers like hydroxy propyl methyl cellulose (HPMC and methyl cellulose (MC along with film modifiers like poly vinyl pyrrolidone K30 (PVP K30, and sodium lauryl sulphate (SLS as solubilizing agents were evaluated. The prepared MDFs were evaluated for in vitro dissolution characteristics, in vitro disintegration time, and their physicomechanical properties. All the prepared MDFs showed good mechanical properties like tensile strength, folding endurance, and % elongation. MDFs were evaluated by means of FTIR, SEM, and X-RD studies. MDFs with 7.5% (w/w of HPMC E3 gave better dissolution properties when compared to HPMC E5, HPMC E15, and MC. MDFs with PVP K30 and SLS gave superior dissolution properties when compared to MDFs without PVP K30 and SLS. The dissolution properties of MDFs with PVP K30 were superior when compared to MDFs with SLS. In the case of F3 containing 7.5% of HPMC E3 and 0.04% of PVP K30, complete and faster release was observed within 60 sec when compared to other formulations. Release kinetics data reveals diffusion is the release mechanism.

  9. Small-angle neutron scattering study of the short-range organization of dispersed CsNi[Cr(CN){sub 6}] nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Ridier, Karl; Gillon, Béatrice; André, Gilles; Chaboussant, Grégory, E-mail: gregory.chaboussant@cea.fr [Laboratoire Léon Brillouin, UMR12 CEA-CNRS, 91191 Gif-sur-Yvette (France); Catala, Laure; Mazérat, Sandra; Mallah, Talal [Institut de Chimie Moléculaire et des Matériaux d' Orsay, CNRS, Université Paris-Sud, 91405 Orsay (France)

    2015-09-21

    Prussian blue analogues magnetic nanoparticles (of radius R{sub 0} = 2.4–8.6 nm) embedded in PVP (polyvinylpyrrolidone) or CTA{sup +} (cetyltrimethylammonium) matrices have been studied using neutron diffraction and small angle neutron scattering (SANS) at several concentrations. For the most diluted particles in neutral PVP, the SANS signal is fully accounted for by a “single-particle” spherical form factor with no structural correlations between the nanoparticles and with radii comparable to those inferred from neutron diffraction. For higher concentration in PVP, structural correlations modify the SANS signal with the appearance of a structure factor peak, which is described using an effective “mean-field” model. A new length scale R{sup * }≈ 3R{sub 0}, corresponding to an effective repulsive interaction radius, is evidenced in PVP samples. In CTA{sup +}, electrostatic interactions play a crucial role and lead to a dense layer of CTA{sup +} around the nanoparticles, which considerably alter the SANS patterns as compared to PVP. The SANS data of nanoparticles in CTA{sup +} are best described by a core-shell model without visible inter-particle structure factor.

  10. Identification of heterotic patterns between expired proprietary, NDSU, and industry shortseason maize inbred lines

    Directory of Open Access Journals (Sweden)

    Mohammed A. A. Bari

    2016-11-01

    Full Text Available Maize (Zea mays L. inbred lines are under restricted use, protected by Patent and Plant Variety Protection (PVP laws. Research objectives were i to identify and validate heterotic groups and patterns, and ii to determine if ex-PVP lines are useful for continued genetic progress in short-season environments. Three groups of crosses were made following North Carolina Mating Design II (NCII including 12 NDSU, 24 ex-PVP lines, and seven current industry testers. Hybrids were planted in four different experiments at six ND environments following partially balanced lattice experimental designs in 2011 and 2012. Top heterotic patterns were selected based upon grain yield and other agronomic traits. Our research indicates most ex-PVP lines are genetically narrow and may not be immediately useful. Less protection (5-yr vs. 20-yr might increase usefulness of ex-PVP lines. This change in intellectual property will allow public breeders to develop better versions of industry lines carrying known weaknesses.

  11. Study of cyanide removal from contaminated water using zinc peroxide nanomaterial.

    Science.gov (United States)

    Uppal, Himani; Tripathy, S Swarupa; Chawla, Sneha; Sharma, Bharti; Dalai, M K; Singh, S P; Singh, Sukhvir; Singh, Nahar

    2017-05-01

    The present study highlights the potential application of zinc peroxide (ZnO2) nanomaterial as an efficient material for the decontamination of cyanide from contaminated water. A process patent for ZnO2 synthesis has been granted in United States of America (US Patent number 8,715,612; May 2014), South Africa, Bangladesh, and India. The ZnO2 nanomaterial was capped with polyvinylpyrrolidone (PVP) to control the particle size. The PVP capped ZnO2 nanomaterial (PVP-ZnO2) before and after adsorption of cyanide was characterized by scanning electron microscope, transmission electron microscope, X-ray diffractometer, Fourier transform infrared spectroscopy and time of flight-secondary ion mass spectrometry. The remaining concentration of cyanide after adsorption by PVP-ZnO2 was determined using ion chromatograph. The adsorption of cyanide over PVP-ZnO2 was also studied as a function of pH, adsorbent dose, time and concentration of cyanide. The maximum removal of cyanide was observed in pH range 5.8-7.8 within 15min. The adsorption data was fitted to Langmuir and Fruendlich isotherm and it has been observed that data follows both the isotherms and also follows second order kinetics. Copyright © 2016. Published by Elsevier B.V.

  12. Radiation synthesized poly(n-vinyl-2-pyrrolidone)-stabilized-gold nanoparticles as LSPR-based optical sensor for mercury ions estimation

    Energy Technology Data Exchange (ETDEWEB)

    Misra, Nilanjal; Kumar, Virendra, E-mail: vkrawat75@gmail.com, E-mail: vkumar@barc.gov.in; Goel, Narender Kumar; Varshney, Lalit [Bhabha Atomic Research Centre, Radiation Technology Development Division (India)

    2015-07-15

    Poly(n-vinyl-2-pyrrolidone)-stabilized-gold nanoparticles (PVP-Au-NPs) have been synthesized via a green-{sup 60}Co-Gamma radiolytic route and employed as a localized surface plasmon resonance (LSPR)-based optical sensor for estimation of trace quantities of Hg{sup 2+} ion in aqueous solutions. The in situ generated PVP-Au-NPs were characterized using UV–vis spectroscopy, transmission electron microscopy, and particle size analysis techniques. Reaction conditions were optimized to obtain uniformly dispersed PVP-Au-NPs with average particle size of 7.1 ± 1.6 nm (±s), which exhibited a narrow LSPR band at ∼527 nm. The decrease in LSPR band intensity of PVP-Au-NPs with increase in Hg{sup 2+} ion concentration was found to be linear in the Hg{sup 2+} ion concentration range of 0–100 nM. The LSPR-based PVP-Au-NPs optical sensor system was found to be selective for Hg{sup 2+} and independent of interference from other metal ions such as Ca{sup 2+,} Cu{sup 2+}, Cd{sup 2+}, and Fe{sup 2+} up to a concentration of 500 nM.

  13. Synthesis, characterization and Monte Carlo simulation of CoFe{sub 2}O{sub 4}/Polyvinylpyrrolidone nanocomposites: The coercivity investigation

    Energy Technology Data Exchange (ETDEWEB)

    Mirzaee, Sh, E-mail: sharareh.mirzaee0@gmail.com; Farjami shayesteh, S., E-mail: saber@guilan.ac.ir; Mahdavifar, S, E-mail: mahdavifar@guilan.ac.ir; Hekmatara, S Hoda., E-mail: hd_hekmat@yahoo.com

    2015-11-01

    To study the influence of polymer matrix on the effective magnetic anisotropy constant and coercivity of magnetic nanoparticles, we have synthesized the Cobalt ferrite/Polyvinylpyrrolidone (PVP) nanocomposites by co-precipitation method in four different processes. In addition the Monte Carlo simulation and law of approach to the saturation magnetization have been applied to achieve the anisotropy constants. The obtained experimental and theoretical results showed a decrease in anisotropy constant relative to the bulk cobalt ferrite. We have showed that the PVP matrix can interact with metal cations and made them approximately immobilized to participate in spinel structure. Hence different anisotropy constants or coercivity were obtained for synthesized nanocomposites. In addition, PVP matrix can attach to the surface of magnetic particles and make them approximately non-interacting. The synthesized samples have been characterized by Fourier transform infrared spectroscopy (FT-IR) and X-ray diffraction (XRD). Magnetic measurements were made at room temperature using a vibrating sample magnetometer (VSM). - Highlights: • We studied the effect of polymer matrix on the coercivity of the CoFe{sub 2}O{sub 4}/PVP nanocomposites. • The polymer matrix decreases the anisotropy of the nanocomposite system. • We have synthesized nanocomposites with approximately the same size, but significantly different coercivity. • We showed that the PVP/CoFe{sub 2}O{sub 4} nanocomposite has the considerable coercivity due to the spin hindrance. • Magnetic properties of nanocomposites simulated by Monte Carlo method.

  14. Individual cryopreservation with dimethyl sulfoxide and polyvinylpyrrolidone of ejaculates and pooled semen of three avian species.

    Science.gov (United States)

    Herrera, J A; Quintana, J A; López, M A; Betancourt, M; Fierro, R

    2005-01-01

    Artificial insemination (AI) has been used for avian reproduction due to the discovery of cryoprotectants extending its usefulness both in production of domestic fowl and conservation of wild species. The goal of this study was to assess the effect on domestic and wild fowl pooled semen and individual ejaculate cryopreservation with dimethyl sulfoxide (DMSO) and polyvinylpyrrolidone (PVP). Twenty ejaculates and twenty samples of pooled semen of roosters, pheasants and hawks were frozen in media containing DMSO or PVP. DMSO and PVP cryopreservation are equally effective both for ejaculates and pooled semen. Even PVP is a good alternative since no significant difference was found when compared to DMSO. The fertilizing capacity of fresh and cryopreserved pooled semen was analyzed through AI of hens and female pheasants. Similar fertility rates using DMSO, PVP or frozen-thawed samples demonstrated that reproduction is possible through the use of cryopreserved semen. In the case of female pheasants, the same values were obtained with both cryopreserved and fresh semen.

  15. Polyvinylpyrrolidone-based semi-interpenetrating polymer networks as highly selective and chemically stable membranes for all vanadium redox flow batteries

    Science.gov (United States)

    Zeng, L.; Zhao, T. S.; Wei, L.; Zeng, Y. K.; Zhang, Z. H.

    2016-09-01

    Vanadium redox flow batteries (VRFBs) with their high flexibility in configuration and operation, as well as long cycle life are competent for the requirement of future energy storage systems. Nevertheless, due to the application of perfluorinated membranes, VRFBs are plagued by not only the severe migration issue of vanadium ions, but also their high cost. Herein, we fabricate semi-interpenetrating polymer networks (SIPNs), consisting of cross-linked polyvinylpyrrolidone (PVP) and polysulfone (PSF), as alternative membranes for VRFBs. It is demonstrated that the PVP-based SIPNs exhibit extremely low vanadium permeabilities, which contribute to the well-established hydrophilic/hydrophobic microstructures and the Donnan exclusion effect. As a result, the coulombic efficiencies of VRFBs with PVP-based SIPNs reach almost 100% at 40 mA cm-2 to 100 mA cm-2; the energy efficiencies are more than 3% higher than those of VRFBs with Nafion 212. More importantly, the PVP-based SIPNs exhibit a superior chemical stability, as demonstrated both by an ex situ immersion test and continuously cycling test. Hence, all the characterizations and performance tests reported here suggest that PVP-based SIPNs are a promising alternative membrane for redox flow batteries to achieve superior cell performance and excellent cycling stability at the fraction of the cost of perfluorinated membranes.

  16. Effect of hydration on plasma vasopressin, renin, and aldosterone responses to head-up tilt

    Science.gov (United States)

    Harrison, M. H.; Geelen, G.; Keil, L. C.; Wade, C. A.; Hill, L. C.

    1986-01-01

    If plasma vasopressin (PVP), plasma renin (PRA), and plasma aldosterone (PA) responses to change in posture are mediated only by alterations in intrathoracic baroreceptor activity hydration status should have minimal influence on these responses. To test this hypothesis, six male subjects underwent 45 min of 70 deg head-up tilt (HUT) following 26 h dehydration, and again, 105 min later, following rehydration. Compared with preceding supine hydrated control values, PVP, PRA, and PA increased (p less than 0.001) during dehydrated HUT, but only PVP and PRA increased during rehydrated HUT (p less than 0.001). The dissociation during rehydrated HUT of PRA and PA may have been related more to the reduction (p less than 0.001) in plasma potassium concentration than to the accompanying decrease (p less than 0.001) in plasma osmolality and sodium concentration. Although increases in PVP and PRA during HUT were attenuated (p less than 0.01) following rehydration, this attenuation was associated with the absence of symptoms of overt hypotension following rehydration. However, since rehydration did not abolish the increases in PVP and PRA induced by HUT, it is concluded that the present observations support the concept of intrathoracic baroreceptor involvement in the regulation of vasopressin secretion and renin release.

  17. Encapsulation of nabumetone by means of -drug: ({beta}-cyclodextrin){sub 2}:polyvinylpyrrolidone ternary complex formation

    Energy Technology Data Exchange (ETDEWEB)

    Valero, Margarita [Departamento de Quimica Fisica, Facultad de Farmacia, Universidad de Salamanca, Salamanca (Spain)]. E-mail: mvalero@usal.es; Tejedor, Javier [Departamento de Quimica Fisica, Facultad de Farmacia, Universidad de Salamanca, Salamanca (Spain); Rodriguez, Licesio J. [Departamento de Quimica Fisica, Facultad de Farmacia, Universidad de Salamanca, Salamanca (Spain)

    2007-10-15

    The aim of the present study was to investigate the effect of the presence of the water-soluble polymer polyvinylpyrrolidone (PVP) MW=24,000 g/mol, on the complexing of the anti-inflammatory drug nabumetone, with {beta}-cyclodextrin ({beta}-CD). The data show that the polymer interacts with the free nabumetone and with the nabumetone:{beta}-CD inclusion complex, in both cases with a stoichiometry of 1:1. The interaction constants are 1.3x10{sup 4} M{sup -1} and 1.6x10{sup 4} M{sup -1}, respectively. The presence of PVP, changes the drug:cyclodextrin interaction, a nabumetone:({beta}-CD){sub 2}:PVP complex being formed. In addition, the presence of PVP, produces a strong increase in the global binding constant, {beta} {sub 2}=(22.12{+-}0.22)x10{sup 6} M{sup -2} at 1% PVP. In the ternary complex, the nabumetone is wrapped at both ends for the {beta}-CD. In this complex the polymer seems to act as a bridge between both {beta}-CD molecules that bind the nabumetone.

  18. Relationship between personality disorder functioning styles and the emotional states in bipolar I and II disorders.

    Science.gov (United States)

    Yao, Jiashu; Xu, You; Qin, Yanhua; Liu, Jing; Shen, Yuedi; Wang, Wei; Chen, Wei

    2015-01-01

    Bipolar disorder types I (BD I) and II (BD II) behave differently in clinical manifestations, normal personality traits, responses to pharmacotherapies, biochemical backgrounds and neuroimaging activations. How the varied emotional states of BD I and II are related to the comorbid personality disorders remains to be settled. We therefore administered the Plutchick - van Praag Depression Inventory (PVP), the Mood Disorder Questionnaire (MDQ), the Hypomanic Checklist-32 (HCL-32), and the Parker Personality Measure (PERM) in 37 patients with BD I, 34 BD II, and in 76 healthy volunteers. Compared to the healthy volunteers, patients with BD I and II scored higher on some PERM styles, PVP, MDQ and HCL-32 scales. In BD I, the PERM Borderline style predicted the PVP scale; and Antisocial predicted HCL-32. In BD II, Borderline, Dependent, Paranoid (-) and Schizoid (-) predicted PVP; Borderline predicted MDQ; Passive-Aggressive and Schizoid (-) predicted HCL-32. In controls, Borderline and Narcissistic (-) predicted PVP; Borderline and Dependent (-) predicted MDQ. Besides confirming the different predictability of the 11 functioning styles of personality disorder to BD I and II, we found that the prediction was more common in BD II, which might underlie its higher risk of suicide and poorer treatment outcome.

  19. Kinetic studies of gas hydrate formation with low-dosage hydrate inhibitors

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Pipeline blockage by gas hydrates is a serious problem in the petroleum industry.Low-dosage inhibitors have been developed for its cost-effective and environmentally acceptable characteristics.In a 1.072-L reactor with methane,ethane and propane gas mixture under the pressure of about 8.5 MPa at 4 °C,hydrate formation was investigated with low-dosage hydrate inhibitors PVP and GHI1,the change of the compressibility factor and gas composition in the gas phase was analyzed,the gas contents in hydrates were compared with PVP and GHI1 added,and the inhibition mechanism of GHI1 was discussed.The results show that PVP and GHI1 could effectively inhibit the growth of gas hydrates but not nucleation.Under the experimental condition with PVP added,methane and ethane occupied the small cavities of the hydrate crystal unit and the ability of ethane entering into hydrate cavities was weaker than that of methane.GHI1 could effectively inhibit molecules which could more readily form hydrates.The ether and hydroxy group of diethylene glycol monobutyl ether have the responsibility for stronger inhibition ability of GHI1 than PVP.

  20. Development and Evaluation of Mouth Dissolving Films of Amlodipine Besylate for Enhanced Therapeutic Efficacy.

    Science.gov (United States)

    Maheswari, K M; Devineni, Pavan Kumar; Deekonda, Sravanthi; Shaik, Salma; Uppala, Naga Pravallika; Nalluri, Buchi N

    2014-01-01

    The present investigation was undertaken with an objective of formulating mouth dissolving films (MDFs) of Amlodipine Besylate (AMLO) to enhance convenience and compliance of the elderly and pediatric patients for better therapeutic efficacy. Film formers like hydroxy propyl methyl cellulose (HPMC) and methyl cellulose (MC) along with film modifiers like poly vinyl pyrrolidone K30 (PVP K30), and sodium lauryl sulphate (SLS) as solubilizing agents were evaluated. The prepared MDFs were evaluated for in vitro dissolution characteristics, in vitro disintegration time, and their physicomechanical properties. All the prepared MDFs showed good mechanical properties like tensile strength, folding endurance, and % elongation. MDFs were evaluated by means of FTIR, SEM, and X-RD studies. MDFs with 7.5% (w/w) of HPMC E3 gave better dissolution properties when compared to HPMC E5, HPMC E15, and MC. MDFs with PVP K30 and SLS gave superior dissolution properties when compared to MDFs without PVP K30 and SLS. The dissolution properties of MDFs with PVP K30 were superior when compared to MDFs with SLS. In the case of F3 containing 7.5% of HPMC E3 and 0.04% of PVP K30, complete and faster release was observed within 60 sec when compared to other formulations. Release kinetics data reveals diffusion is the release mechanism.

  1. Synthesis and Characterization of Polyvinylpyrrolidone Silica Core-Shell Nanocomposite Particles.

    Science.gov (United States)

    Chen, Lian-Xi; Li, Jie; Li, Xi; Zhang, Zhong-Min; Jiao, Cai-Bin

    2015-03-01

    In this work, a novel and facile strategy for making a new type of polymer/silica nanocomposte particle was proposed. Colloidally stable polyvinypyrrolidone (PVP)/silica core-shell nanocomposite particles have been successfully synthesized using an azo initiator via seed polymerization of N-vinyl-2-pyrrolidone (NVP) and VFSs (VFSs) that were derived from vinyl triethoxysilane (VTES). It was suggested from the FTIR and TGA analysis that the copolymerization reaction of NVP with VFSs has been thoroughly carried out. In addition, SEM images showed that PVP/silica nanocomposite particles have relatively rough surface due to surface polymerization in comparison with VFSs. Furthermore, TEM results proved that the size of VFSs had considerable effects on the appearance of PVP/silica nanocomposite particles. Generally, it presented that several silica nanoparticle cores with an average size of 78 nm mainly pack together within each nanocomposite particle after seed polymerization. Interestingly, the average shell thickness was 59 nm for most PVP/silica nanocomposite particles with cores about 242 nm. However, when the core size was large enough to about 504 nm, a series of PVP/silica nanocomposite particles with a relative thin shell were observed.

  2. Development and in Vitro Characterization of Photochemically Crosslinked Polyvinylpyrrolidone Coatings for Drug-Coated Balloons

    Directory of Open Access Journals (Sweden)

    Svea Petersen

    2013-12-01

    Full Text Available Polyvinylpyrrolidone (PVP is a conventionally applied hydrophilic lubricious coating on catheter-based cardiovascular devices, used in order to ease movement through the vasculature. Its use as drug reservoir and transfer agent on drug-coated balloons (DCB is therefore extremely promising with regard to the simplification of its approval as a medical device. Here, we developed a PVP-based coating for DCB, containing paclitaxel (PTX as a model drug, and studied the impact of crosslinking via UV radiation on drug stability, wash off, and transfer during simulated use in an in vitro vessel model. We showed that crosslinking was essential for coating stability and needed to be performed prior to PTX incorporation due to decreased drug bioavailability as a result of photodecomposition and/or involvement in vinylic polymerization with PVP under UV radiation. Moreover, the crosslinking time needed to be carefully controlled. While short radiation times did not provide enough coating stability, associated with high wash off rates during DCB insertion, long radiation times lowered drug transfer efficiency upon balloon expansion. A ten minutes radiation of PVP, however, combined a minimized drug wash off rate of 34% with an efficient drug transfer of 49%, underlining the high potential of photochemically crosslinked PVP as a coating matrix for DCB.

  3. Improvement of poly(vinyl alcohol)/poly(vinyl pyrrolidone) blended hydrogel by radiation crosslinking

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    A series of polyvinyl alcohol (PVA) and polyvinyl pyrrolidone (PVP) blended hydrogel with kappa-carrageenan (KC) were prepared by radiation crosslinking with electron beam to improve the properties of hydrogel as wound dressing. The properties of the blended hydrogels were evaluated in terms of gel fraction, swelling behavior, gel strength and water evaporation from hydrogel. Gel fraction of PVA/PVP was saturated at 50 kGy and the achieved gel fraction was 70%~80%. However, obtained hydrogel was very fragile and produced many bubbles at a dose of 50kGy and above, hence 1%~5% KC were added to give toughness. The rate of gel formation and the toughness of the blended hydrogel were raised after mixing KC. The PVA/PVP/KC blended hydrogel irradiated showed satisfactory properties for wound dressing, it did not produce bubble during irradiation, and it could retard the water evaporation.

  4. Spherically-clustered porous Au-Ag alloy nanoparticle prepared by partial inhibition of galvanic replacement and its application for efficient multimodal therapy.

    Science.gov (United States)

    Jang, Hongje; Min, Dal-Hee

    2015-03-24

    The polyvinylpyrrolidone (PVP)-coated spherically clustered porous gold-silver alloy nanoparticle (PVP-SPAN) was prepared by low temperature mediated, partially inhibited galvanic replacement reaction followed by silver etching process. The prepared porous nanostructures exhibited excellent photothermal conversion efficiency under irradiation of near-infrared light (NIR) and allowed a high payload of both doxorubicin (Dox) and thiolated dye-labeled oligonucleotide, DNAzyme (FDz). Especially, PVP-SPAN provided 10 times higher loading capacity for oligonucleotide than conventional hollow nanoshells due to increased pore diameter and surface-to-volume ratio. We demonstrated highly efficient chemo-thermo-gene multitherapy based on codelivery of Dox and FDz with NIR-mediated photothermal therapeutic effect using a model system of hepatitis C virus infected human liver cells (Huh7 human hepatocarcinoma cell line containing hepatitis C virus NS3 gene replicon) compared to conventional hollow nanoshells.

  5. Polymer versus phosphine stabilized Rh nanoparticles as components of supported catalysts: implication in the hydrogenation of cyclohexene model molecule.

    Science.gov (United States)

    Ibrahim, M; Garcia, M A S; Vono, L L R; Guerrero, M; Lecante, P; Rossi, L M; Philippot, K

    2016-11-28

    The solution synthesis of rhodium nanoparticles (Rh NPs) was achieved from the organometallic complex [Rh(η(3)-C3H5)3] under mild reaction conditions in the presence of a polymer (PVP), a monophosphine (PPh3) and a diphosphine (dppb) as a stabilizer, leading to very small Rh NPs of 2.2, 1.3 and 1.7 nm mean size, with PVP, PPh3 and dppb, respectively. The surface properties of these nanoparticles were compared using a model catalysis reaction namely, hydrogenation of cyclohexene, first under colloidal conditions and then under supported conditions after their immobilization onto an amino functionalized silica-coated magnetite support. PVP-stabilized Rh NPs were the most active catalyst whatever the catalytic conditions as a result of a strong coordination of the phosphine ligands at the metal surface that blocks some surface atoms even after several recycles of the supported nanocatalysts and limit the reactivity of the metallic surface.

  6. Effects of solar radiation on collagen-based biomaterials

    Directory of Open Access Journals (Sweden)

    Alina Sionkowska

    2006-01-01

    Full Text Available The effect of solar radiation on collagen and collagen/synthetic polymer blends in the form of thin films and solutions has been studied by UV-VIS and FTIR spectroscopies. Films and solutions of collagen blended with poly(vinyl alcohol (PVA and poly(vinyl pyrrolidone (PVP were irradiated by solar light. It was found that UV-VIS spectra, which characterize collagen, collagen/PVA, and collagen/PVP blended films, were significantly altered by solar radiation. FTIR spectra of collagen, collagen/PVA, and collagen/PVP films showed that after solar irradiation, the positions of Amide A bands were shifted to lower wavenumbers. There was not any significant alteration in the position of Amide I and Amide II bands of collagen and its blends after solar radiation. The effect of solar UV radiation in comparison with artificial UV radiation has been discussed.

  7. Control of self organization in conjugated polymer fibers.

    Science.gov (United States)

    Chuangchote, Surawut; Fujita, Michiyasu; Sagawa, Takashi; Sakaguchi, Hiroshi; Yoshikawa, Susumu

    2010-11-01

    We propose new strategy to facilitate the fabrication of conjugated polymer fiber with higher oriented structures, which focused on electrospinning of a blend solution of regioregular poly(3-hexylthiophene) (rr-P3HT) and poly(vinyl pyrrolidone) (PVP). SEM observation revealed that the blend system forms homogeneous composite nanofibers. This system exhibits the specific feature of strong interchain contribution of P3HT from UV-vis absorption, fluorescence spectroscopic, XRD, and photoelectron spectrometric (for HOMO levels) investigations. We also demonstrate the removal of the PVP component from the P3HT/PVP composite fibers through the selective extraction and such strong interchain stacking of pristine P3HT fiber mat can be remarkably maintained.

  8. POLY(N-VINYLPYRROLIDONE)-MODIFIED SURFACES REPEL PLASMA PROTEIN ADSORPTION

    Institute of Scientific and Technical Information of China (English)

    Xiao-li Liu; Zhao-qiang Wu; Dan Li; Hong Chen

    2012-01-01

    The present work aimed to study the interaction between plasma proteins and PVP-modified surfaces under more complex protein conditions.In the competitive adsorption of fibrinogen (Fg) and human serum albumin (HSA),the modified surfaces showed preferential adsorption of HSA.In 100% plasma,the amount of Fg adsorbed onto PVP-modified surfaces was as low as 10 ng/cm2,suggesting the excellent protein resistance properties of the modified surfaces.In addition,immunoblots of proteins eluted from the modified surfaces after plasma contact confirmed that PVP-modified surfaces can repel most plasma proteins,especially proteins that play important roles in the process of blood coagulation.

  9. Effects of solution properties on the morphology and diameters of nanofibers fabricated by electrospinning

    Science.gov (United States)

    Jing, Hongjun; Jiang, Yadong; Du, Xiaosong

    2010-10-01

    In this paper, four different series of polymer solutions were presented to study the effects of solution properties on the morphology and diameters of nanofibers, including the polyethersulfone (PES) dissolving in N, N-dimethylformamide, polyvinylpyrrolidone (PVP) in ethanol, poly(acrylic acid) (PAA) in water and poly(vinylidene fluoride) (PVDF) in N, Ndimethyl acetamide. These solutions revealed different conditions of the formation of beads, the spatial structures and the diameter of fibers. The PVDF nanofibers had plenty of small beads on the fibers, while the other three were uniform fibers without beads. The nanofibers of PES, PVP and PVDF showed good three dimensional structures except the PAA fibrous membranes. The change of fiber diameters of PVDF was much larger than that of PVP.

  10. Oxidation of polyvinylpyrrolidone and an ethoxylate surfactant in phase-inversion wastewater.

    Science.gov (United States)

    Loraine, Gregory A

    2008-04-01

    In this paper, components of an industrial wastewater that cause operational problems during biological treatment were oxidized by UV light and hydrogen peroxide (UV/H202). Preoxidation of wastewater was shown to remove polyvinylpyrrolidone (PVP) and ethoxylate surfactant and increase overall biodegradability. Several UV intensities and hydrogen peroxide concentrations were tested to find optimal conditions for the complete depolymerization of PVP in a synthetic wastewater composed of high concentrations of hydroxyl radical scavengers. To compare treatment options, absorption isotherms for PVP on granular activated carbon (GAC) in water and in the synthetic phase-inversion wastewater matrix were determined. The data were extrapolated to estimate the cost of using UV/H2O2, GAC, or off-site treatment. It was found that UV/H2O2 pretreatment was economically viable. Incomplete oxidation of an ethoxylate surfactant increased foaming tendency and foam stability; however, extended oxidation (> 90 minutes) destroyed the foam.

  11. Improved Performance of Organic Thin Film Transistor with an Inorganic Oxide/Polymer Double-Layer Insulator

    Institute of Scientific and Technical Information of China (English)

    ZHAO Yi-Hua; DONG Gui-Fang; WANG Li-Duo; QIU Yong

    2007-01-01

    We employ the Ta2O5/PVP (poly-4-vinylphenol) double-layer gate insulator to improve the performance of pentacene thin-film transistors. It is found that the double-layer insulator has low leakage current, smooth surface and considerably high capacitance. Compared to Ta2O5 insulator layers, the device with the Ta2O5/PVP double-layer insulator exhibits an enhancement of the Reid-effect mobility from 0.21 to 0.54 cm2 /Vs, and the decreasing threshold voltage from 4.38V to -2.5 V. The results suggest that the Ta2O5/PVP double-layer insulator is a potential gate insulator for fabricating OTFTs with good electrical performance.

  12. Silver micro- and nano-particles obtained using different glycols as reducing agents and measurement of their conductivity

    Directory of Open Access Journals (Sweden)

    Moudir Naïma

    2016-01-01

    Full Text Available Synthesis of silver micro- and nano-particles for the preparation of conductive pastes for the metallization of solar cells was realized by chemical reduction in the presence and absence of poly(vinyl-pyrrolidone (PVP. Silver nitrate was used as a precursor in the presence of three polyols (ethylene glycol, di-ethylene glycol and propylene glycol tested at experimental temperatures near their boiling points. Six samples were obtained by this protocol. Three silver powders obtained without the use of PVP have a metallic luster appearance; however, the samples produced using an excess of PVP are in the form of stable colloidal dispersions of silver nano-particles. Structural characterizations of samples using a scanning electron microscope and X-ray diffractometer show a good crystallinity and spherical morphology. From DSC and TGA analyses, it was noticed that all the nano-silvers present in the colloidal suspension have the same thermal behavior.

  13. Amphiphilic poly-N-vinylpyrrolidone nanocarriers with incorporated model proteins

    Energy Technology Data Exchange (ETDEWEB)

    Kuskov, A N [Department of Polymers, D I Mendeleyev University of Chemical Technology, 9 Miusskaya Square, Moscow 125047 (Russian Federation); Villemson, A L [Department of Chemistry, M V Lomonosov Moscow State University, 119992 Moscow (Russian Federation); Shtilman, M I [Department of Polymers, D I Mendeleyev University of Chemical Technology, 9 Miusskaya Square, Moscow 125047 (Russian Federation); Larionova, N I [Department of Chemistry, M V Lomonosov Moscow State University, 119992 Moscow (Russian Federation); Tsatsakis, A M [Medical School, University of Crete, Voutes, 71409 Heraklion, Crete (Greece); Tsikalas, I [Department of Chemistry and Foundation for Research and Technology-Hellas (FORTH), University of Crete, PO Box 2208, Heraklion 71003, Crete (Greece); Rizos, A K [Department of Chemistry and Foundation for Research and Technology-Hellas (FORTH), University of Crete, PO Box 2208, Heraklion 71003, Crete (Greece)

    2007-05-23

    New nanoscaled polymeric carriers have been prepared on the basis of different amphiphilic water-soluble derivatives of poly-N-vinylpyrrolidone (PVP). The polymer self-assembly and interaction with model proteins (Bowman-Birk soybean proteinase inhibitor (BBI) and its hydrophobized derivatives) were studied in aqueous media. The possibility of inclusion of both BBI and hydrophobized oleic acid derivatives of BBI in amphiphilic PVP aggregates was investigated. It was ascertained that polymeric particles of size 50-80 nm were formed in certain concentrations of amphiphilic PVP and poorly soluble dioleic acid derivatives of BBI. Such polymeric aggregates are capable of solubilization of dioleoyl BBI with a concomitant prevention of its inactivation at low pH values.

  14. Amphiphilic poly-N-vinylpyrrolidone nanocarriers with incorporated model proteins

    Science.gov (United States)

    Kuskov, A. N.; Villemson, A. L.; Shtilman, M. I.; Larionova, N. I.; Tsatsakis, A. M.; Tsikalas, I.; Rizos, A. K.

    2007-05-01

    New nanoscaled polymeric carriers have been prepared on the basis of different amphiphilic water-soluble derivatives of poly-N-vinylpyrrolidone (PVP). The polymer self-assembly and interaction with model proteins (Bowman-Birk soybean proteinase inhibitor (BBI) and its hydrophobized derivatives) were studied in aqueous media. The possibility of inclusion of both BBI and hydrophobized oleic acid derivatives of BBI in amphiphilic PVP aggregates was investigated. It was ascertained that polymeric particles of size 50-80 nm were formed in certain concentrations of amphiphilic PVP and poorly soluble dioleic acid derivatives of BBI. Such polymeric aggregates are capable of solubilization of dioleoyl BBI with a concomitant prevention of its inactivation at low pH values.

  15. Comparison of therapeutic effect between percutaneous vertebroplasty and kyphoplasty on vertebral compression fracture

    Institute of Scientific and Technical Information of China (English)

    ZHOU Jian-lin; LIU Shi-qing; MING Jiang-hua; PENG Hao; QIU Bo

    2008-01-01

    Objective: To compare the clinical efficacy of percutaneous vertebroplasty ( PVP) with percutaneous kyphoplasty ( PKP ) in the treatment of vertebral compression fracture (VCF).Methods: Ninety-eight patients with VCF were treated by PVP (n =42) or PKP (n = 56). The anterior midline and posterior heights of vertebrae body, preoperative and postoperative visual analogue scale (VAS), operation time and amount of blood loss were compared between 2 groups.Results: There was statistical difference in vertebral height between two groups (P<0. 01). No significant difference was seen in VAS, operation time and blood loss between two groups (P<0. 05).Conclusions: PKP and PVP have the similar therapeutic efficacy in treatment of VCF with minimal invasion, less operation time and blood loss. However, PKP is superior in the recovery of vertebral height.

  16. Preparation of silver-coated glass frit and its application in silicon solar cells

    Science.gov (United States)

    Feng, Xiang; Biyuan, Li; Yingfen, Li; Jian, Zhou; Weiping, Gan

    2016-07-01

    A simple electroless plating process was employed to prepare silver-coated glass frits for solar cells. The surface of the glass frits was modified with polyvinyl-pyrrolidone (PVP) before the electroless plating process. Infrared (IR) spectroscopy, field emission scanning electron microscopy (FESEM), and x-ray diffraction (XRD) were used to characterize the PVP modified glass frits and investigate the mechanism of the modification process. It was found that the PVP molecules adsorbed on the glass frit surface and reduced the silver ions to the silver nanoparticles. Through epitaxial growth, these nanoparticles were uniformly deposited onto the surface of the glass frit. Silicon solar cells with this novel silver coating exhibited a photoelectric conversion efficiency increase of 0.33%. Compared with the electroless plating processes, this method provides a simple route to prepare silver-coated glass frits without introducing impurity ions.

  17. Preparation of silver-coated glass frit and its application in silicon solar cells

    Institute of Scientific and Technical Information of China (English)

    向锋; 李碧渊; 黎应芬; 周健; 甘卫平

    2016-01-01

    A simple electroless plating process was employed to prepare silver-coated glass frits for solar cells. The surface of the glass frits was modified with polyvinyl-pyrrolidone (PVP) before the electroless plating process. Infrared (IR) spectroscopy, field emission scanning electron microscopy (FESEM), and x-ray diffraction (XRD) were used to characterize the PVP modified glass frits and investigate the mechanism of the modification process. It was found that the PVP molecules adsorbed on the glass frit surface and reduced the silver ions to the silver nanoparticles. Through epitaxial growth, these nanoparticles were uniformly deposited onto the surface of the glass frit. Silicon solar cells with this novel silver coating exhibited a photoelectric conversion efficiency increase of 0.33%. Compared with the electroless plating processes, this method provides a simple route to prepare silver-coated glass frits without introducing impurity ions.

  18. Preparation and Characterization of Monodisperse Nickel Nanoparticles by Polyol Process

    Institute of Scientific and Technical Information of China (English)

    LI Peng; GUAN Jianguo; ZHANG Qingjie; ZHAO Wenyu

    2005-01-01

    Polymer-protected monodisperse nickel nanoparticles were synthesized by a modified polyol reduction method in the presence of poly ( N-vinyl- 2-pyrrolidone ). These nanoparticles were characterized by transmission electron microscopy (TEM), X- ray diffraction ( XRD ), selected area electron diffraction ( SAED ), as well as vibrating sample magnetometer (VSM). The experimental results show that the addition of PVP and the concentration of NaOH have strong influences on the size, agglomeration and uniformity of nanoparticles. In the presence of PVP and NaOH with low concentrations, monodisperse nickel nanoparticles with average diameters about 42 nm were obtained and characterized to be pure nickel crystalline with fcc structure. Secondary structures such as clusters, loops, and strings resulted from magnetic interactions between particles were observed. The chemical interaction between the PVP and nickel nanoparticles was found by FTIR. The saturation magnetization ( Ms ), remanent magnetization (Mr) and coercivity ( Hc ) of these nickel nanoparticles are lower than those of bulk nickel.

  19. Co-relationship of physical stability of amorphous dispersions with enthalpy relaxation.

    Science.gov (United States)

    Bansal, S S; Kaushal, A M; Bansal, A K

    2008-11-01

    Physical stability studies of valdecoxib (VLB) and its solid dispersions with PVP (1, 2, 5, 10, 15 and 20% w/w) were carried out by Differential Scanning Calorimetry (DSC). Change in specific heat with time was measured to determine the degree of crystallinity of amorphous drug and its binary dispersions after storage at 40 degrees C and 75% RH. The rate of crystallization was found to decrease with increasing PVP concentration and time for 10% crystallization (t90%) was found to increase significantly for the amorphous drug when formulated as PVP dispersions. Enthalpy relaxation was found to be inversely correlated with t90% (min) values and was found to be a good predictor of devitrification tendency and hence stability of amorphous VLB.

  20. Improving the Efficiency of Organic Solar Cells upon Addition of Polyvinylpyridine

    Directory of Open Access Journals (Sweden)

    Rita Rodrigues

    2014-12-01

    Full Text Available We report on the efficiency improvement of organic solar cells (OPVs based on the low energy gap polyfluorene derivative, APFO-3, and the soluble C60 fullerene PCBM, upon addition of a residual amount of poly (4-vinylpyridine (PVP. We find that the addition of 1% by weight of PVP with respect to the APFO-3 content leads to an increase of efficiency from 2.4% to 2.9%. Modifications in the phase separation details of the active layer were investigated as a possible origin of the efficiency increase. At high concentrations of PVP, the blend morphology is radically altered as observed by Atomic Force Microscopy. Although the use of low molecular weight additives is a routine method to improve OPVs efficiency, this report shows that inert polymers, in terms of optical and charge transport properties, may also improve the performance of polymer-based solar cells.

  1. Improving the Efficiency of Organic Solar Cells upon Addition of Polyvinylpyridine.

    Science.gov (United States)

    Rodrigues, Rita; Meira, Rui; Ferreira, Quirina; Charas, Ana; Morgado, Jorge

    2014-12-22

    We report on the efficiency improvement of organic solar cells (OPVs) based on the low energy gap polyfluorene derivative, APFO-3, and the soluble C60 fullerene PCBM, upon addition of a residual amount of poly (4-vinylpyridine) (PVP). We find that the addition of 1% by weight of PVP with respect to the APFO-3 content leads to an increase of efficiency from 2.4% to 2.9%. Modifications in the phase separation details of the active layer were investigated as a possible origin of the efficiency increase. At high concentrations of PVP, the blend morphology is radically altered as observed by Atomic Force Microscopy. Although the use of low molecular weight additives is a routine method to improve OPVs efficiency, this report shows that inert polymers, in terms of optical and charge transport properties, may also improve the performance of polymer-based solar cells.

  2. Mechanism of co-pyrolysis of coal-tar pitch with polyvinylpyridine

    Energy Technology Data Exchange (ETDEWEB)

    Grzyb, B.; Machnikowski, J. [Institute of Chemistry and Technology of Petroleum and Coal, Wroclaw University of Technology, Gdanska 7/9, 50-344 Wroclaw (Poland); Weber, J.V. [Laboratoire de Chimie et Applications, Universite de Metz-IUT, /Rue V. Demange, 57-500 Saint Avold (France)

    2004-08-01

    Co-pyrolysis of coal-tar pitch and poly(4-vinylpyridine) cross-linked with 25wt.% of divinylbenzene (PVP) or the oxidized form of the co-polymer (PVPox) was studied as a possible way of manufacturing of carbonaceous materials enriched in nitrogen. Interactions of pitch with polymers were evaluated using thermogravimetry, elemental analysis, infrared spectroscopy in the DRIFT mode, X-ray photoelectron spectroscopy and optical microscopy. The tendency to depolymerization of PVP on heat treatment results in a little effect of the polymer on the thermal behaviour of the blend. PVPox is a stronger modifier of pitch carbonization behaviour and much more efficient source of nitrogen in the co-pyrolysis. The principal chemical interaction between pitch and PVPox is the dehydrogenative polymerization of pitch constituents induced by polymer oxygen groups. The oxidation of PVP does not affect the nitrogen functionalities transformation on pyrolysis.

  3. Controlled growth of silver nanoparticles in a hydrothermal process

    Institute of Scientific and Technical Information of China (English)

    Juan Zou; Yao Xu; Bo Hou; Dong Wu; Yuhan Sun

    2007-01-01

    A two-step synthesis was used to control the shape of silver nanoparticles. First, a few spherical silver nanoparticles, ~10 nm in size, were prepared via reduction of Ag+ ions in aqueous Ag(NH3)2NO3 by poly(N-vinyl-2-pyrrolidone) (PVP). Then, in a subsequent hydrothermal treatment,the remaining Ag+ ions were reduced by PVP into polyhedral nanoparticles, or larger spherical nanoparticles formed from the small spherical seed silver nanoparticles in the first step. The morphology and size of the resultant particles depend on the hydrothermal temperature, PVP/Ag molar ratio and concentration of Ag+ ions. By using UV-visible spectroscopy (UV-vis), transmission electron microscopy (TEM) and powder X-ray diffraction (XRD), the possible growth mechanism of the silver nanoparticles was discussed.

  4. An Alternative Synthesis Route of LiFePO4-Carbon Composites for Li-Ion Cathodes

    Directory of Open Access Journals (Sweden)

    Yongbing Lou

    2013-01-01

    Full Text Available LiFePO4-Carbon (LFP/C composites with high purity and good crystallinity were prepared by an improved environmentally benign and low-cost solvothermal method. Capping agent polyvinylpyrrolidone (PVP and polyethylene glycol (PEG-400 showed no significant dispersive effect during the synthesis. These capping agents were converted into networking carbons after annealing, which consequently improved the charge and discharge performance. It was able to deliver a high initial discharge specific capacity of 154.1 mAh g−1 for sample prepared with PVP and 145.6 mAh g−1 for sample prepared with PEG-400 while having great capacity retention. The rate capability and cycling performance of LFP/C samples prepared with PVP or PEG-400 at high current rates were significantly improved compared to the LFP/C sample prepared without a capping agent.

  5. Sensitive Adsorptive Voltammetric Method for Determination of Bisphenol A by Gold Nanoparticle/Polyvinylpyrrolidone-Modified Pencil Graphite Electrode.

    Science.gov (United States)

    Yaman, Yesim Tugce; Abaci, Serdar

    2016-05-25

    A novel electrochemical sensor gold nanoparticle (AuNP)/polyvinylpyrrolidone (PVP) modified pencil graphite electrode (PGE) was developed for the ultrasensitive determination of Bisphenol A (BPA). The gold nanoparticles were electrodeposited by constant potential electrolysis and PVP was attached by passive adsorption onto the electrode surface. The electrode surfaces were characterized by electrochemical impedance spectroscopy (EIS) and scanning electron microscopy (SEM). The parameters that affected the experimental conditions were researched and optimized. The AuNP/PVP/PGE sensor provided high sensitivity and selectivity for BPA recognition by using square wave adsorptive stripping voltammetry (SWAdSV). Under optimized conditions, the detection limit was found to be 1.0 nM. This new sensor system offered the advantages of simple fabrication which aided the expeditious replication, low cost, fast response, high sensitivity and low background current for BPA. This new sensor system was successfully tested for the detection of the amount of BPA in bottled drinking water with high reliability.

  6. Modulating the Optoelectronic Properties of Silver Nanowires Films: Effect of Capping Agent and Deposition Technique

    Directory of Open Access Journals (Sweden)

    D. Lopez-Diaz

    2015-11-01

    Full Text Available Silver nanowires 90 nm in diameter and 9 µm in length have been synthesized using different capping agents: polyvinyl pyrrolidone (PVP and alkyl thiol of different chain lengths. The nanowire structure is not influenced by the displacement of PVP by alkyl thiols, although alkyl thiols modify the lateral aggregation of nanowires. We examined the effect of the capping agent and the deposition method on the optical and electrical properties of films prepared by Spray and the Langmuir-Schaefer methodologies. Our results revealed that nanowires capped with PVP and C8-thiol present the best optoelectronic properties. By using different deposition techniques and by modifying the nanowire surface density, we can modulate the optoelectronic properties of films. This strategy allows obtaining films with the optoelectronic properties required to manufacture touch screens and electromagnetic shielding.

  7. Preparation and characterization of chitosan/poly(Vinyl alcohol)/poly(Vinyl pyrrolidone) electrospun fibers

    Institute of Scientific and Technical Information of China (English)

    MA Guiping; YANG Dongzhi; ZHOU Yingshan; JIN Yu; NIE Jun

    2007-01-01

    Ultrafine fibers of chitosan/poly(vinyl alcohol)/poly(vinyl pyrrolidone) (CS/PVA/PVP) were prepared via electrospinning.The structure and morphology of CS/PVA/PVP ultrafine fibers was characterized by the Fourier transform inflared (FT-IR) spectroscope and scanning electron microscope (SEM).Furthermore.the effects of the concentration of PVA,PVP and the electrospinning voltage on the morphology of ultrafine fibers were investigated by the SEM.When the concentration of PVA was at the range of 30wt%-40wt%,ultrafine fibers could be obtained.The diameter distributions of ultrafine fibers decreased when the electrospinning voltage increased from 20to 30kV. The rough surface fibers could be obtained after etching with CHCl3.

  8. Study on Drying Process of 3Al2O3·2SiO2 Mullite Gel

    Institute of Scientific and Technical Information of China (English)

    SONG Hui-feng; KANG Zhuang; GU Li-xia

    2008-01-01

    Monophasic mullite gel with composition 3Al2Q3·2SiO2 was prepared by the sol-gel method using aluminium nitrate nonahydrate, aluminium-tri-isopropoxide, and tetraethylorthosili-cate as reagents.Gels with different drying control chemical additives ( DCCAs ) and polyvinylpyrrolidone(PVP) as spinning assistant were dried at several temperatures.The influences of temperature.DCCAs and PVP in the drying process were investigated.N, N-dimethylformamide(DMF) was the optimum DCCA at 70℃ in the drying process.PVP decreased the solvent volatilization speed and prevented gel crack to a certain extent.FTIR results revealed that free water, ethanol, and isopropanol were completely removed by the drying procedure.

  9. Effect of electron beam irradiation and poly(vinylpyrrolidone addition on mechanical properties of polycaprolactone with empty fruit bunch fibre (OPEFB composite

    Directory of Open Access Journals (Sweden)

    2009-04-01

    Full Text Available Biodegradable composites or green composites were prepared by melt blending technique using polycaprolactone and oil palm empty fruit bunch fibre (OPEFB. Since OPEFB is not compatible with PCL a binder, poly(vinyl pyrrolidone, (PVP was used to improve the interaction between PCL and OPEFB. The composites produced were irradiated using electron beam to improve the mechanical properties. The tensile, flexural and impact strengths of PCL/OPEFB composites were improved by addition of 1% by weight of PVP and irradiated with 10 kGy of electron beam. The FTIR spectra indicate a slight increase of frequencies at C=O peaks from 1730 to 1732 cm–1 after irradiation indicates some interaction between C=O and O–H. The surface morphology of the facture surface obtained from tensile test shows no fibre pull out indicating good adhesion between the OPEFB and PCL after addition of PVP.

  10. Photoisomerization of merocyanine 540 in polymer-surfactant aggregate

    Indian Academy of Sciences (India)

    Sobhan Sen; Dipankar Sukul; Partha Dutta; Kankan Bhattacharyya

    2002-02-01

    Photoisomerization of merocyanine 540 (MC540) in a polymer-surfactant aggregate is studied using picosecond time resolved emission spectroscopy. The aggregate consists of the polymer, poly(vinylpyrrolidone) (PVP) and the surfactant, sodium dodecyl sulphate (SDS). With increase in the concentration of SDS in an aqueous solution of MC540 containing PVP, the emission quantum yield and lifetime of MC540 increase markedly. This indicates marked retardation in the nonradiative photoisomerization process of MC540, when it binds to the polymersurfactant aggregate. The critical association concentration of SDS for binding to PVP has been found to be 0.5 mM. This is about 16 times lower than the CMC of SDS in pure water (8 mM).

  11. Electrochemical behavior and voltammetric determination of vanillin based on an acetylene black paste electrode modified with graphene-polyvinylpyrrolidone composite film.

    Science.gov (United States)

    Deng, Peihong; Xu, Zhifeng; Zeng, Rongying; Ding, Chunxia

    2015-08-01

    The graphene-polyvinylpyrrolidone composite film modified acetylene black paste electrode (GR-PVP/ABPE) was fabricated and used to determine vanillin. In 0.1M H3PO4 solution, the oxidation peak current of vanillin increased significantly at GR-PVP/ABPE compared with bare ABPE, PVP/ABPE and GR/ABPE. The oxidation mechanism was discussed. The experimental conditions that exert influence on the voltammetric determination of vanillin, such as supporting electrolytes, pH values, accumulation potential and accumulation time, were optimized. Besides, the interference, repeatability, reproducibility and stability measurements were also evaluated. Under the optimal experimental conditions, the oxidation peak current was proportional to vanillin concentration in the range of 0.02-2.0 μM, 2.0-40 μM and 40-100 μM. The detection limit was 10nM. This sensor was used successfully for vanillin determination in various food samples.

  12. Influence of the electronic distribution of polymers in the spatial conformation of polymer grafted carbon nanotube composites

    Energy Technology Data Exchange (ETDEWEB)

    Garate, H. [Universidad de Buenos Aires, FCEyN, Depto. de Fisica IFIBA-CONICET LPyMC, Pabellon I, Buenos Aires 1428 (Argentina); Universidad de Buenos Aires, FCEyN, Depto. de Quimica Organica, (CIHIDECAR-CONICET) Buenos Aires 1428 (Argentina); De Falco, A. [Universidad de Buenos Aires, FCEyN, Depto. de Fisica IFIBA-CONICET LPyMC, Pabellon I, Buenos Aires 1428 (Argentina); Moreno, M.S. [Centro Atomico Bariloche, 8400 S.C. de Bariloche (Argentina); Fascio, M.L. [Universidad de Buenos Aires, FCEyN, Depto. de Quimica Organica, (CIHIDECAR-CONICET) Buenos Aires 1428 (Argentina); Goyanes, S. [Universidad de Buenos Aires, FCEyN, Depto. de Fisica IFIBA-CONICET LPyMC, Pabellon I, Buenos Aires 1428 (Argentina); Consejo Nacional de Investigaciones Cientificas y Tecnicas (CONICET) (Argentina); D' Accorso, N.B., E-mail: norma@qo.fcen.uba.ar [Universidad de Buenos Aires, FCEyN, Depto. de Quimica Organica, (CIHIDECAR-CONICET) Buenos Aires 1428 (Argentina); Consejo Nacional de Investigaciones Cientificas y Tecnicas (CONICET) (Argentina)

    2012-08-15

    In this work we report the covalent functionalization of multiwalled carbon nanotubes (MWCNTs) with polyacrylonitrile (PAN) and polyvinylpyridine (PVP) by the graft from method. Differences in the electronic distribution of both polymers resulted in different interaction between polymers and the nanotubes. It was found that PVP chains wrapped the nanotubes while nanotubes functionalized with PAN presented PAN chains forming amorphous entanglements on the nanoscale linked to the MWCNTs. Differences in the conformation between both polymers and the MWCNTs can be attributed to interactions between the aromatic groups in PVP and the MWCNTs through {pi}-{pi} stacking. The absence of aromatic groups in the case of the PAN chains favours the interaction between them. The functionalization efficiency was characterized using Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA) and UV-vis spectroscopy, while morphological changes were characterized by high resolution transmission electron microscopy.

  13. Electrospun Polymer Blend Nanofibers for Tunable Drug Delivery: The Role of Transformative Phase Separation on Controlling the Release Rate.

    Science.gov (United States)

    Tipduangta, Pratchaya; Belton, Peter; Fábián, László; Wang, Li Ying; Tang, Huiru; Eddleston, Mark; Qi, Sheng

    2016-01-01

    Electrospun fibrous materials have a wide range of biomedical applications, many of them involving the use of polymers as matrices for incorporation of therapeutic agents. The use of polymer blends improves the tuneability of the physicochemical and mechanical properties of the drug loaded fibers. This also benefits the development of controlled drug release formulations, for which the release rate can be modified by altering the ratio of the polymers in the blend. However, to realize these benefits, a clear understanding of the phase behavior of the processed polymer blend is essential. This study reports an in depth investigation of the impact of the electrospinning process on the phase separation of a model partially miscible polymer blend, PVP K90 and HPMCAS, in comparison to other conventional solvent evaporation based processes including film casting and spin coating. The nanoscale stretching and ultrafast solvent removal of electrospinning lead to an enhanced apparent miscibility between the polymers, with the same blends showing micronscale phase separation when processed using film casting and spin coating. Nanoscale phase separation in electrospun blend fibers was confirmed in the dry state. Rapid, layered, macroscale phase separation of the two polymers occurred during the wetting of the fibers. This led to a biphasic drug release profile from the fibers, with a burst release from PVP-rich phases and a slower, more continuous release from HPMCAS-rich phases. It was noted that the model drug, paracetamol, had more favorable partitioning into the PVP-rich phase, which is likely to be a result of greater hydrogen bonding between PVP and paracetamol. This led to higher drug contents in the PVP-rich phases than the HPMCAS-rich phases. By alternating the proportions of the PVP and HPMCAS, the drug release rate can be modulated.

  14. Short-term relative antibacterial effect of octenidine dihydrochloride on the oral microflora in orthodontically treated patients.

    Science.gov (United States)

    Dogan, Alev Aksoy; Adiloglu, Ali K; Onal, Suleyman; Cetin, Emel Sesli; Polat, Esra; Uskun, Ersin; Koksal, Fatih

    2008-11-01

    To evaluate the efficacy of common antiseptic mouth rinses and octenidine dihydrochloride (OCT). The antibacterial activities of antiseptics against total and cariogenic bacteria (Streptococcus mutans and Lactobacillus species) in saliva were studied in vitro and in vivo. After unstimulated saliva was collected, one of the mouth rinse solutions was applied for 30seconds. Saliva samples were collected 15, 30, 60, and 120min later and evaluated for their bacterial count. OCT had a significantly greater inhibitory effect on the studied bacteria than 0.2% chlorhexidine gluconate (CHX) and 7.5% polyvinylpyrrolidone-iodine complex (PVP-I) from 15min to 120min following the application (p<0.01). The antiseptic efficacy of 0.2% CHX on total bacteria and Lactobacillus species was very similar to the efficacy observed with 7.5% PVP-I mouth solution from 15min up to 120min. Streptococcus mutans was completely inhibited by 0.15mg/ml PVP-I, 0.5mg/ml CHX, and 0.1mg/ml OCT concentrations, while Streptococcus salivarius was inhibited by 0.15mg/ml PVP-I, 2mg/ml CHX, and 0.8mg/ml OCT concentrations. Lactococcus lactis subspecies lactis was inhibited with 0.00313mg/ml OCT, 30mg/ml PVP-I, and 0.0063mg/ml CHX concentrations. OCT compared favorably with CHX and PVP-I in its antibacterial effects, both in vitro and in vivo (p<0.01).

  15. Increased electrochemical properties of ruthenium oxide and graphene/ruthenium oxide hybrid dispersed by polyvinylpyrrolidone

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Yao; Zhang, Xiong; Zhang, Dacheng [Key Laboratory of Applied Superconductivity, Institute of Electrical Engineering, Chinese Academy of Sciences, Beijing 100190 (China); Ma, Yanwei, E-mail: ywma@mail.iee.ac.cn [Key Laboratory of Applied Superconductivity, Institute of Electrical Engineering, Chinese Academy of Sciences, Beijing 100190 (China)

    2012-11-15

    Highlights: Black-Right-Pointing-Pointer A good dispersion of RuO{sub 2} and graphene/RuO{sub 2} is obtained by polyvinylpyrrolidone. Black-Right-Pointing-Pointer PVP as a dispersant also can prevent the formation of metal Ru in graphene/RuO{sub 2}. Black-Right-Pointing-Pointer The max capacitances of the hybrid and RuO{sub 2} reach 435 and 597 F g{sup -1} at 0.2 A g{sup -1}. Black-Right-Pointing-Pointer The hybrid shows the best rate capability of 39% at 50 A g{sup -1}. - Abstract: Ruthenium oxide has been prepared by a sol-gel method. Polyvinylpyrrolidone (PVP) as an excellent polymeric dispersant is adopted to prevent aggregation of ruthenium oxide. In order to enhance the rate capability of ruthenium oxide, graphene with residual oxygen functional groups as a 2D support has been merged into ruthenium oxide. These oxygen functional groups not only favor to form stable few layers of graphene colloids, but also offer the sites to anchor ruthenium oxide nanoparticles. X-ray diffraction infers that PVP can also hinder the partial formation of Ru by blocking the direct contact between the Ru{sup 3+} and the graphene in the sol-gel synthesis of the hybrids. The ruthenium oxide and the graphene/ruthenium oxide hybrids dispersed by PVP have superior electrochemical properties due to good dispersing and protecting ability of PVP. Especially, the hybrids using PVP exhibit the best rate capability, indicating that the composites possess an advanced structure of combining sheets and particles in nano-scale.

  16. Electrodeposited polymer encapsulated nickel sulphide thin films: frequency switching material

    Energy Technology Data Exchange (ETDEWEB)

    Jana, Sumanta, E-mail: sumantajana85@gmail.com [Department of Chemistry, Bengal Engineering and Science University, Botanic Garden, Howrah 711103, WB (India); Mukherjee, Nillohit [Centre of Excellence for Green Energy and Sensor Systems, Bengal Engineering and Science University, Howrah 711103, WB (India); Chakraborty, Biswajit [Department of Chemistry, Vivekananda Mahavidyalay, Burdwan 713103, WB (India); Mitra, Bibhas Chandra [Department of Physics, Bengal Engineering and Science University, Botanic Garden, Howrah 711103, WB (India); Mondal, Anup, E-mail: anupmondal2000@yahoo.co.in [Department of Chemistry, Bengal Engineering and Science University, Botanic Garden, Howrah 711103, WB (India)

    2014-05-01

    Graphical abstract: Polyvinylpyrrolidone encapsulated NiS thin films were synthesized electrochemically. The light induced frequency switching study of the synthesized material was carried out and it was observed that the films performed well as a switching device under 1 Sun illumination. This pulse generation within an insulating polymer encapsulated semicondctor matrix (PVP NiS) might be due to surface covering which leads to reduction of recombination process. Highlights: • PVP-NiS thin films were electrochemically synthesized. • Encapsulation of PVP causes surface modification of NiS by reducing surface states. • The synthesized thin films were used as frequency switching material which generates ~ 50 Hz frequency under 1 Sun irradiation. Abstract: Polyvinylpyrrolidone (PVP) encapsulated nickel sulfide (NiS) thin films have been synthesized electrochemically from aqueous solution of hydrated nickel chloride (NiCl₂, 6H₂O), thioacetamide (CH₃C(S) NH₂) (TAA) and polyvinylpyrrolidone (PVP). Surface modification of nickel sulfide (NiS) thin films was achieved by this polymer encapsulation. X-ray diffraction (XRD), high resolution transmission electron microscope (HRTEM), field emission scanning electron microscopy (FESEM) and Energy dispersive X-radiation (EDAX) techniques were used for the characterization of thin films. Infrared spectroscopy (IR) confirmed the formation of polymer encapsulated semiconductor. Frequency switching generation study shows that the encapsulated material could be used as a frequency switching device that generates a frequency ~ 50 Hz under 1 Sun illumination. Encapsulation with PVP causes surface modification that reduces the surface states and barrier height. As a result, the width of the depletion region decreases. So the number of electron-hole pairs increases. Consequently, the number of excitons and exciton related emission increases and this leads to reduction of recombination process and shows photo induced

  17. Investigation and Evaluation of an in Situ Interpolymer Complex of Carbopol with Polyvinylpyrrolidone as a Matrix for Gastroretentive Tablets of Ranitidine Hydrochloride.

    Science.gov (United States)

    Yusif, Rehab Mohammad; Abu Hashim, Irhan Ibrahim; Mohamed, Elham Abdelmonem; El Rakhawy, Mohamed Magdy

    2016-01-01

    Carbopol (CP) is a biocompatible bioadhesive polymer used as a matrix for gastroretentive (GR) tablets, however, its rapid hydration shortens its bioadhesion and floating when incorporated in effervescent formulae. The interpolymer complexation of CP with polyvinylpyrrolidone (PVP) significantly reduced the excessive hydration of CP, prolonging floating and maintaining the mucoadhesiveness. In early attempts, a lengthy process was followed to prepare such an interpolymer complex. In this study, an in situ interpolymer complexation between CP and two grades of PVP (K25 and K90) in 0.1 N HCl was investigated and characterized by Fourier transform infrared spectroscopy (FT-IR) and differential scanning calorimetry (DSC). Hence, directly compressed GR tablets of different combinations of PVP and CP with sodium bicarbonate (SB) as an effervescent agent were examined for prolonged gastroretention and sustained release of ranitidine hydrochloride (RHCl) as a model drug. Tablets were evaluated for in vitro buoyancy, bioadhesiveness, swelling, and drug release in 0.1 N HCl. All GR tablets containing PVP-CP combinations achieved more prolonged floating (>24 h) than CP tablets (5.2 h). Their bioadhesiveness, swelling, and drug release were dependent on the PVP molecular weight and its ratio to CP. Drug release profiles of all formulae followed non-Fickian diffusion. Formula containing the PVP K90-CP combination at a respective ratio of 1 : 3 (P90C13) was a promising system, exhibiting good floating and bioadhesive properties as well as sustained drug release. Abdominal X-ray imaging of P90C13 formula, loaded with barium sulfate, in six healthy volunteers showed a mean gastric retention period of 6.8±0.3 h.

  18. Clinical Outcome and Safety of Multilevel Vertebroplasty: Clinical Experience and Results

    Energy Technology Data Exchange (ETDEWEB)

    Mailli, Leto, E-mail: lmailli@hotmail.com; Filippiadis, Dimitrios K.; Brountzos, Elias N.; Alexopoulou, Efthymia; Kelekis, Nikolaos; Kelekis, Alexios [Attikon University Hospital, Second Department of Radiology, Athens University School of Medicine (Greece)

    2013-02-15

    To compare safety and efficacy of percutaneous vertebroplasty (PVP) when treating up to three vertebrae or more than three vertebrae per session. We prospectively compared two groups of patients with symptomatic vertebral fractures who had no significant response to conservative therapy. Pathologic substrate included osteoporosis (n = 77), metastasis (n = 24), multiple myeloma (n = 13), hemangioma (n = 15), and lymphoma (n = 1). Group A patients (n = 94) underwent PVP of up to three treated vertebrae (n = 188). Group B patients (n = 36) underwent PVP with more than three treated vertebrae per session (n = 220). Decreased pain and improved mobility were recorded the day after surgery and at 12 and 24 months after surgery per clinical evaluation and the use of numeric visual scales (NVS): the Greek Brief Pain Inventory, a linear analogue self-assessment questionnaire, and a World Health Organization questionnaire. Group A presented with a mean pain score of 7.9 {+-} 1.1 NVS units before PVP, which decreased to 2.1 {+-} 1.6, 2.0 {+-} 1.5 and 2.0 {+-} 1.5 NVS units the day after surgery and at 12 and 24 months after surgery, respectively. Group B presented with a mean pain score of 8.1 {+-} 1.3 NVS units before PVP, which decreased to 2.2 {+-} 1.3, 2.0 {+-} 1.5, and 2.1 {+-} 1.6 NVS units the day after surgery and at 12 and 24 months after surgery, respectively. Overall pain decrease and mobility improvement throughout the follow-up period presented no statistical significance neither between the two groups nor between different underlying aetiology. Reported cement leakages presented no statistical significance between the two groups (p = 0.365). PVP is an efficient and safe technique for symptomatic vertebral fractures independently of the vertebrae number treated per session.

  19. Enhanced near infrared emission in water-soluble NdF3 nanocrystals by Ba2+ doping

    Institute of Scientific and Technical Information of China (English)

    Ting Fan; Qinyuan Zhang; Zhonghong Jiang

    2012-01-01

    A simple and efficient method for the synthesis of water-soluble NdF3 and NdF3:Ba2+ nanocrystals under hydrothermal conditions is established. The method involves the coating of the nanocrystals with a layer of hydrophilic polymer polyvinylpyrrolidone (PVP). The as-prepared products are characterized by powder X-ray diffraction, field emission scanning electronic microscopy, Fourier transform infrared spectroscopy, and photoluminescence spectroscopy. The PVP coating transforms the nanocrystals into a biocompatible material and improves the fluorescence intensity of NdF3 in the near infrared (NIR) region. The morphology of the nanoparticles changes, whereas the fluorescence intensity of NdF3 in the NIR region increases when a small amount of Ba2+ is doped into the NdFs/PVP nanoparticles.%A simple and efficient method for the synthesis of water-soluble NdF3 and NdF3∶Ba2+ nanocrystals under hydrothermal conditions is established.The method involves the coating of the nanocrystals with a layer of hydrophilic polymer polyvinylpyrrolidone (PVP).The as-prepared products are characterized by powder X-ray diffraction,field emission scanning electronic microscopy,Fourier transform infrared spectroscopy,and photoluminescence spectroscopy.The PVP coating transforms the nanocrystals into a biocompatible material and improves the fluorescence intensity of NdF3 in the near infrared (NIR) region.The morphology of the nanoparticles changes,whereas the fluorescence intensity of NdF3 in the NIR region increases when a small amount of Ba2+ is doped into the NdF3/PVP nanoparticles.

  20. Preparation, property of the complex of carboxymethyl chitosan grafted copolymer with iodine and application of it in cervical antibacterial biomembrane

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Yu [School of Materials Science and Engineering, Beijing Institute of Technology, Beijing 100081 (China); Yang, Yumin; Liao, Qingping [Zhejiang Sanchuang Biological Technology Co., Ltd., Jiaxing, Zhejiang Province 314031 (China); Yang, Wei [School of Materials Science and Engineering, Beijing Institute of Technology, Beijing 100081 (China); Ma, Wanfeng [Zhejiang Sanchuang Biological Technology Co., Ltd., Jiaxing, Zhejiang Province 314031 (China); Zhao, Jian [Department of Gynaecology and Obstetrics, The First Hospital of Peking University, Beijing 100034 (China); Zheng, Xionggao [School of Materials Science and Engineering, Beijing Institute of Technology, Beijing 100081 (China); Yang, Yang [Zhejiang Sanchuang Biological Technology Co., Ltd., Jiaxing, Zhejiang Province 314031 (China); Chen, Rui [Department of Gynaecology and Obstetrics, The First Hospital of Peking University, Beijing 100034 (China)

    2016-10-01

    Cervical erosion is one of the common diseases of women. The loop electrosurgical excisional procedure (LEEP) has been used widely in the treatment of the cervical diseases. However, there are no effective wound dressings for the postoperative care to protect the wound area from further infection, leading to increased secretion and longer healing time. Iodine is a widely used inorganic antibacterial agent with many advantages. However, the carrier for stable iodine complex antibacterial agents is lack. In the present study, a novel iodine carrier, Carboxymethyl chitosan-g-(poly(sodium acrylate)-co-polyvinylpyrrolidone) (CMCTS-g-(PAANa-co-PVP), was prepared by graft copolymerization of sodium acrylate (AANa) and N-vinylpyrrolidone (NVP) to a carboxymethyl chitosan (CMCTS) skeleton. The obtained structure could combine prominent property of poly(sodium acrylate) (PAANa) anionic polyelectrolyte segment and good complex property of polyvinylpyrrolidone (PVP) segment to iodine. The bioactivity of CMCTS could also be kept. The properties of the complex, CMCTS-g-(PAANa-co-PVP)-I{sub 2}, were studied. The in vitro experiment shows that it has broad-spectrum bactericidal effects to virus, fungus, gram-positive bacteria and gram-negative bacteria. A CMCTS-g-(PAANa-co-PVP)-I{sub 2} complex contained cervical antibacterial biomembrane (CABM) was prepared. The iodine release from the CABM is pH-dependent. The clinic trial results indicate that CABM has better treatment effectiveness than the conventional treatment in the postoperative care of the LEEP operation. - Highlights: • The multifunctional iodine complexing carrier CMCTS-g-(PAANa-co-PVP) was prepared. • CMCTS-g-(PAANa-co-PVP)-I{sub 2} with high antibacterial property and bio-safety was studied. • By compositing it with CMCTS and gelatin further, CABM with multifunction was deduced. • The releasing properties of the activated iodine from CABM showed pH sensitivity. • CABM showed good treating effect for

  1. Physicochemical properties of tadalafil solid dispersions - Impact of polymer on the apparent solubility and dissolution rate of tadalafil.

    Science.gov (United States)

    Wlodarski, K; Sawicki, W; Haber, K; Knapik, J; Wojnarowska, Z; Paluch, M; Lepek, P; Hawelek, L; Tajber, L

    2015-08-01

    To improve solubility of tadalafil (Td), a poorly soluble drug substance (3μg/ml) belonging to the II class of the Biopharmaceutical Classification System, its six different solid dispersions (1:1, w/w) in the following polymers: HPMC, MC, PVP, PVP-VA, Kollicoat IR and Soluplus were successfully produced by freeze-drying. Scanning electron microscopy showed a morphological structure of solid dispersions typical of lyophilisates. Apparent solubility and intrinsic dissolution rate studies revealed the greatest, a 16-fold, increase in drug solubility (50μg/ml) and a significant, 20-fold, dissolution rate enhancement for the Td/PVP-VA solid dispersion in comparison with crystalline Td. However, the longest duration of the supersaturation state in water (27μg/ml) over 24h was observed for the Td solid dispersion in HPMC. The improved dissolution of Td from Td/PVP-VA was confirmed in the standard dissolution test of capsules filled with solid dispersions. Powder X-ray diffraction and thermal analysis showed the amorphous nature of these binary systems and indicated the existence of dispersion at the molecular level and its supersaturated character, respectively. Nevertheless, as evidenced by film casting, the greatest ability to dissolve Td in polymer was determined for PVP-VA. The crystallization tendency of Td dispersed in Kollicoat IR could be explained by the low Tg (113°C) of the solid dispersion and the highest difference in Hansen solubility parameters (6.8MPa(0.5)) between Td and the polymer, although this relationship was not satisfied for the partially crystalline dispersion in PVP. Similarly, no correlation was found between the strength of hydrogen bonds investigated using infrared spectroscopy and the physical stability of solid dispersions or the level of supersaturation in aqueous solution.

  2. Polyvinyl pyrrolidone/carrageenan blend hydrogels with nanosilver prepared by gamma radiation for use as an antimicrobial wound dressing.

    Science.gov (United States)

    Singh, Durgeshwer; Singh, Antaryami; Singh, Rita

    2015-01-01

    Hydrogels were prepared using polyvinyl pyrrolidone (PVP) blended with carrageenan by gamma irradiation at different doses of 25 and 40 kGy. Gel fraction of hydrogels prepared using 10 and 15% PVP in combination with 0.25 and 0.5% carrageenan was evaluated. Based on gel fraction, 15% PVP in combination with 0.25% carrageenan and radiation dose of 25 kGy was selected for the preparation of hydrogels with nanosilver. Radiolytic synthesis of silver nanoparticles within the PVP hydrogel was carried out. The hydrogels with silver nanoparticles were assessed for antimicrobial effectiveness and physical properties of relevance to clinical performance. Fluid handling capacity (FHC) for PVP/carrageenan was 2.35 ± 0.39-6.63 ± 0.63 g/10 cm(2) in 2-24 h. No counts for Pseudomonas aeruginosa, Staphylococcus aureus, Escherichia coli, and Candida albicans were observed in the presence of hydrogels containing 100 ppm nanosilver after 3-6 h. The release of silver from hydrogels containing 100 ppm nanosilver was 20.42 ± 1.98 ppm/100 cm(2) in 24 h. Hydrogels containing 100 ppm nanosilver with efficient FHC demonstrated potential microbicidal activity (≥3 log10 decrease in CFU/ml) against wound pathogens, P. aeruginosa, S. aureus, E. coli, and C. albicans. PVP/carrageenan hydrogels containing silver nanoparticles can be used as wound dressings to control infection and facilitate the healing process for burns and other skin injuries.

  3. Oral subchronic exposure to silver nanoparticles in rats.

    Science.gov (United States)

    Garcia, Tania; Lafuente, Daisy; Blanco, Jordi; Sánchez, Domènec J; Sirvent, Juan J; Domingo, José L; Gómez, Mercedes

    2016-06-01

    Because of their extremely small size, silver nanoparticles (AgNPs) show unique physical and chemical properties, with specific biological effects, which make them particularly attractive for being used in a number of consumer applications. However, these properties also influence the potential toxicity of AgNPs. In this study, we assessed the potential toxic effects of an in vivo oral sub-chronic exposure to polyvinyl pyrrolidone coated AgNPs (PVP-AgNPs) in adult male rats. We also assessed if oral PVP-AgNPs exposure could alter the levels of various metals (Fe, Mg, Zn and Cu) in tissues. Rats were orally given 0, 50, 100 and 200 mg/kg/day of PVP-AgNPs. Silver (Ag) accumulation in tissues, Ag excretion, biochemical and hematological parameters, metal levels, as well as histopathological changes and subcellular distribution following PVP-AgNPs exposure, were also investigated. After 90 days of treatment, AgNPs were found within hepatic and ileum cells. The major tissue concentration of Ag was found in ileum of treated animals. However, all tissues of PVP-AgNPs-exposed animals showed increased levels of Ag in comparison with those of rats in the control group. No harmful effects in liver and kidney, as well as in biochemical markers were noted at any treatment dose. In addition, no hematological or histopathological changes were found in treated animals. However, significant differences in Cu and Zn levels were found in thymus and brain of PVP-AgNPs-treated rats.

  4. P31 - Long-Term Prospective Study of Osteoporotic Patients Treated with Percutaneous Vertebroplasty after Fragility Fractures

    Science.gov (United States)

    Mazzantini, M.; Torre, C.; Di Munno, O.

    2010-01-01

    Introduction: The purpose of this study was to evaluate factors that could increase the occurrence of new vertebral fractures (VFx) after percutaneous vertebroplasty (PVP) procedures. Methods: In our prospective study, we included patients of both sexes with osteoporosis (OP) and at least one painful VFx. We performed a baseline biochemical evaluation (including vitamin D plasma levels) and collected demographic, BMD, and clinical data. One hundred and fifteen patients were treated with PVP and assigned to oral bisphosphonates plus Ca and vitamin D. The patients returned for follow-up visits after 1, 3, and 6 months, and every 6 months thereafter. X-rays of the dorsolumbar spine were repeated every 12 months, or in the event of pain that may indicate VFx occurrence. Results: The mean follow-up duration was 39 +/− 16 months (range, 15–79). Thirty-two patients (27.8%) sustained new fragility VFx, all symptomatic. All the fractured patients agreed to undergo a new PVP. We compared the patients who had sustained new VFx to those who had not, and found significantly lower BMI, total hip, and femoral neck T-scores in the group with new VFx. Furthermore, baseline plasma levels of 25(OH) vitamin D (25(OH)D) were significantly lower in this group. Analysis of plasma levels of 25(OH)D 12 months after PVP showed that a significant difference still persisted: 22 +/− 12 (group with new VFx) vs 41 +/− 22 ng/ml (group with no VFx; p < 0.01). Conclusions: We found that in patients with OP treated with PVP, the incidence of new VFx was 27.8% after 39 months; low BMI, BMD, and vitamin D are factors associated with increased risk of new VFx in patients treated with PVP.

  5. Effect of pH and biological media on polyvinylpyrrolidone-capped silver nanoparticles

    Science.gov (United States)

    Lau, Chew Ping; Abdul-Wahab, Mohd Firdaus; Jaafar, Jafariah; Chan, Giek Far; Rashid, Noor Aini Abdul

    2016-07-01

    Toxicity and mobility of silver nanoparticles (AgNPs) vary in different surrounding environments. Surface coatings or functionalization, temperature, pH, dissolved oxygen concentration, nanoparticle concentration, the presence of organic matter, and ionic strength are factors which dictate the transformation of AgNPs in terms of aggregation and stabilization. Thus, the purpose of this study is to investigate the behavior of polyvinylpyrrolidone (PVP)-capped AgNPs at different pHs (pH 2 to 10) and in different biological media (0.1 M phosphate buffer, nutrient broth, P5 and modified P5 media) analyzed using UV-Vis spectroscopy and zeta potential analyzer. The PVP-capped AgNPs changed its behavior in the presence of varying media, after 24 h incubation with shaking at 200 rpm at 30°C. No aggregation was observed at pH 4 to 10, but distinctive at very low pH of 2. Low pH further destabilized PVP-capped AgNPs after 24 h of incubation. High ionic strength 0.1 M phosphate buffer also resulted in slow aggregation and eventually destabilized the nanoparticles. Biological media (nutrient broth, P5 and modified P5 media) containing organic components caused aggregation of the PVP-capped AgNPs. The increase in glucose and nutrient broth concentrations led to increased aggregation. However, PVP-capped AgNPs stabilized after 24 h incubation in media containing a high concentration of glucose and nutrient broth. The results demonstrate that low pH value, high ionic strength and the content of the biological media can influence the stability of AgNPs. This provides information on the aggregation behavior of PVP-capped AgNPs and can possibly further predict the fate, transport as well as the toxicity of silver nanoparticles after being released into the aquatic environment.

  6. Large-scale and highly efficient synthesis of micro- and nano-fibers with controlled fiber morphology by centrifugal jet spinning for tissue regeneration.

    Science.gov (United States)

    Ren, Liyun; Pandit, Vaibhav; Elkin, Joshua; Denman, Tyler; Cooper, James A; Kotha, Shiva P

    2013-03-21

    PLLA fibrous tissue scaffolds with controlled fiber nanoscale surface roughness are fabricated with a novel centrifugal jet spinning process. The centrifugal jet spinning technique is a highly efficient synthesis method for micron- to nano-sized fibers with a production rate up to 0.5 g min(-1). During the centrifugal jet spinning process, a polymer solution jet is stretched by the centrifugal force of a rotating chamber. By engineering the rheological properties of the polymer solution, solvent evaporation rate and centrifugal force that are applied on the solution jet, polyvinylpyrrolidone (PVP) and poly(l-lactic acid) (PLLA) composite fibers with various diameters are fabricated. Viscosity measurements of polymer solutions allowed us to determine critical polymer chain entanglement limits that allow the generation of continuous fiber as opposed to beads or beaded fibers. Above a critical concentration at which polymer chains are partially or fully entangled, lower polymer concentrations and higher centrifugal forces resulted in thinner fibers. Etching of PVP from the PLLA-PVP composite fibers doped with increasing PVP concentrations yielded PLLA fibers with increasing nano-scale surface roughness and porosity, which increased the fiber hydrophilicity dramatically. Scanning electron micrographs of the etched composite fibers suggest that PVP and PLLA were co-contiguously phase separated within the composite fibers during spinning and nano-scale roughness features were created after the partial etching of PVP. To