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Sample records for pvp

  1. Synthesis and characterization of micrometer Cu/PVP architectures

    SciTech Connect

    Luo, Huajuan; Zhao, Yanbao; Sun, Lei

    2011-08-15

    Graphical abstract: A simple method for the synthesis of novel micrometer flower-like Cu/PVP architectures was introduced. Highlights: {yields} Micrometer flower-like copper/polyvinylpyrrolidone architectures were obtained by a simple chemical route. {yields} The amount of N{sub 2}H{sub 4}{center_dot}H{sub 2}O, the reaction temperature, the molar ratio of CuCl{sub 2} to PVP and different molecular weights of PVP play an important role in the controlling the morphology of the Cu/PVP architectures. {yields} A possible mechanism of the formation of Cu/PVP architectures was discussed. -- Abstract: Micrometer-sized flower-like Cu/polyvinylpyrrolidone (PVP) architectures are synthesized by the reduction of copper (II) salt with hydrazine hydrate in aqueous solution in the presence of PVP capping agent. The resulting Cu/PVP architectures are investigated by UV-vis spectroscopy, transmission electron microscopy (TEM), X-ray powder diffraction (XRD), and scanning electron microscopy (SEM). The Cu/PVP flowers have uniform morphologies with an average diameter of 10 {mu}m, made of several intercrossing plates. The formation of Cu/PVP flowers is a new kinetic control process, and the factors such as the amount of N{sub 2}H{sub 4}{center_dot}H{sub 2}O, reaction temperature, molar ratio of CuCl{sub 2} to PVP and molecular weight of PVP have significant effect on the morphology of Cu/PVP architectures. A possible mechanism of the formation of micrometer Cu/PVP architectures was discussed.

  2. Gelation of PAAm-PVP composites: A fluorescence study

    NASA Astrophysics Data System (ADS)

    Evingür, Gülşen Akin; Kaygusuz, Hakan; Erim, F. Bedia; Pekcan, Önder

    2014-05-01

    Hybrid hydrogels are a new class of composite materials. Polyacrylamide (PAAm) hydrogels are mainly produced by free radical crosslinking copolymerization (FCC) of AAm in the presence of N, N‧-methylene bis (acrylamide) (BIS) as the crosslinker. Pyranine doped PAAm-poly (N-vinyl pyrrolidone) (PVP) composite were prepared with different amounts of PVP varying in the range between 0.0015 and 0.1 gr. It was observed that pyranine molecules as a fluoroprobe bind to AAm and PVP chains upon the initiation of the polymerization, causing the fluorescence spectra of the bonded pyranines shift to the shorter wavelengths. The sol-gel phase transition and its universality were monitored and tested as a function of PVP contents. Observations around the critical point show that the gel fraction exponent, β, agreed with the percolation result for below 0.025 gr PVP contents. However, classical result was observed above 0.0125 gr PVP content.

  3. Composites for the pressure vessel industry. PVP-Volume 302

    SciTech Connect

    Bees, W.J.; Newaz, G.M.; Narita, Yoshihiro; Takezono, S.; Qatu, M.S.; Hirano, T.; Miyazaki, N.; Nakagaki, M.

    1995-11-01

    The topics included in this volume are: (1) design and analysis of composite shell and plate components in PVP; (2) design and analysis of composite material and adhesive structures; (3) analysis of different material application in PVP; and (4) composites and functionally gradient material. Separate abstracts were prepared for most papers in this book.

  4. PVP-CA composite preparation and its characteristics

    NASA Astrophysics Data System (ADS)

    Cui, Ruiyao

    Polyvinylpyrrolidone (PVP) is a commonly used polymer that has some excellent properties, such as great strength and biocompatibility. Cellulose Acetate (CA) is another excellent polymer that has been employed in many applications, including drug. PVP-CA composite has both strength and flexible properties that can be used as ultrafiltration membranes or the drug release system. PVP-CA composites comprise a new class of materials that have been the scope of this work. In this research, the electrospun PVP-CA composites were prepared under different concentrations. Then, the impact of different electrospinning parameters on fiber diameters was investigated. Moreover, acetic acid and acetone were used as solvents for dissolving PVP, CA respectively. For comparison, PVP in water and CA in acetone was each deposited on the aluminum foil by electrospinning, forming a two-layer structure. Scanning electron microscopy(SEM) and Raman spectroscopy test were carried out. From the test results, fibers with 200nm to 1um diameter were prepared and the interaction between PVP and CA were proved. Then the oil absorption testing was carried out. The membrane structure of the electrospun composite fibers showed good oil absorption capacity, that was twice higher than the 2-layer PVP-CA fibers.

  5. Continuous manufacturing of delta mannitol by cospray drying with PVP.

    PubMed

    Vanhoorne, V; Van Bockstal, P-J; Van Snick, B; Peeters, E; Monteyne, T; Gomes, P; De Beer, T; Remon, J P; Vervaet, C

    2016-03-30

    Mannitol is a frequently used diluent in the production of tablets due to its non-hygroscopic character and low drug interaction potential. Although the δ-polymorph of mannitol has superior tabletability in comparison to α- and β-mannitol, the latter are most commonly used because large-scale production of δ-mannitol is difficult. Therefore, a continuous method for production of δ-mannitol was developed in the current study. Spray drying an aqueous solution of mannitol and PVP in a ratio of 4:1 resulted in formation of δ-mannitol. The tabletability of a physical mixture of spray dried δ-mannitol with PVP (5%) and paracetamol (75%) was clearly superior to the tabletability of physical mixtures consisting of spray dried α- and β-mannitol with PVP (5%) and paracetamol (75%) which confirmed the excellent tableting properties of the δ-polymorph. In addition, a coprocessing method was applied to coat paracetamol crystals with δ-mannitol and PVP. The tabletability of the resulting coprocessed particles consisting of 5% PVP, 20% δ-mannitol and 75% paracetamol reached a maximal tensile strength of 2.1 MPa at a main compression pressure of 260 MPa. Moreover the friability of tablets compressed at 184 MPa was only 0.5%. This was attributed to the excellent compression properties of δ-mannitol and the coating of paracetamol crystals with δ-mannitol and PVP during coprocessing. PMID:26851355

  6. Emission Analysis Of Pr{sup 3+}: PVP And Nd{sup 3+}: PVP Films

    SciTech Connect

    Sivaiah, K.; Buddhudu, S.

    2010-12-01

    Here we report on the results concerning the absorption and emission spectra of RE{sup 3+} (Pr{sup 3+} or Nd{sup 3+}) doped PVP polymer films. The absorption spectrum of Pr{sup 3+}: PVP polymer film has shown three absorption bands at 444 nm ({sup 3}H{sub 4{yields}}{sup 3}P{sub 2}), 469nm ({sup 3}H{sub 4{yields}}{sup 3}P{sub 1}) and 481nm ({sup 3}H{sub 4{yields}}{sup 3}P{sub 0}). From the Pr{sup 3+}: PVP polymer film, an emission at 603 nm ({sup 1}D{sub 2{yields}}{sup 3}H{sub 4}) has been observed with an excitation at 443 nm ({sup 3}H{sub 4{yields}}{sup 3}P{sub 2}). The absorption spectrum of Nd{sup 3+}: PVP polymer film has exhibited eleven absorption bands at 324 nm, 383 nm, 432 nm, 462 nm, 511 nm, 526 nm, 580 nm, 686 nm, 746 nm, 799 nm, and 869 nm which are assigned to the electronic transitions of {sup 4}I{sub 9/2{yields}}{sup 4}D{sub 7/2}, {sup 4}I{sub 9/2{yields}}{sup 2}D{sub 3/2}, {sup 4}I{sub 9/2{yields}}{sup 4}P{sub 1/2}, {sup 4}I{sub 9/2{yields}}{sup 4}G{sub 11/2}, {sup 4}I{sub 9/2{yields}}{sup 4}G{sub 9/2}, {sup 4}I{sub 9/2{yields}}{sup 4}G{sub 7/2}, {sup 4}I{sub 9/2{yields}}{sup 4}G{sub 5/2}, {sup 4}I{sub 9/2{yields}}{sup 2}F{sub 9/2}, {sup 4}I{sub 9/2{yields}}{sup 2}F{sub 7/2}, {sup 4}I{sub 9/2{yields}}{sup 2}H{sub 9/2} and {sup 4}I{sub 9/2{yields}}{sup 4}F{sub 3/2} respectively. From the Nd{sup 3+}: PVP polymer film, an emission transition has been measured at 1055 nm ({sup 4}F{sub 3/2{yields}}{sup 4}I{sub 11/2}) with an excitation at 324 nm ({sup 4}I{sub 9/2{yields}}{sup 4}D{sub 7/2}). For the host polymer film, structural properties have been studied from the measurement of XRD, FTIR, Raman spectra. For this film thermal properties have also been investigated from the measured profiles of TGA-DTA.

  7. Induction of IgG memory responses with polyvinylpyrrolidone (PVP) is antigen dose dependent

    SciTech Connect

    Lite, H.S.; Braley-Mullen, H.

    1981-03-01

    Irradiated recipients of spleen cells from mice primed with a very low dose (0.0025 ..mu../g) of the thymus-independent (TI) antigen polyvinylpyrrolidone (PVP) produced PVP-specific IgG memory responses after secondary challenge with a T-dependent (TD) form of PVP, PVP-HRBC. The IgG memory responses induced by low doses of PVP were similar in magnitude to those induced by the TD antigen PVP-HRBC. The induction of IgG memory by the TI form of antigen was markedly dependent on the dose of PVP used to prime donor mice. Spleen cells from mice primed with an amount of PVP (0.25 ..mu..g) that induces an optimal primary IgM response did not produce significant IgG antibody after challenge with PVP-HRBC. The inability of higher doses of PVP to induce IgG memory may be due, at least in part, to the fact that such doses of PVP were found to induce tolerance in PVP-specific B cells and could suppress the induction of memory induced by PVP-HRBC. Low doses of PVP did not interfere with the induction of memory by PVP-HRBC. Expression of IgG memory responses in recipients of PVP-HRBC or low-dose PVP-primed cells was found to be T cell dependent. Moreover, only primed T cells could reconstitute the respnse of recipients of primed B cells, suggesting that the ability of PVP to induce IgG memory may be related to its ability to prime T helper cells. Expression of the IgG memory response in recipient mice also required the use of a TD antigen for secondary challenge, i.e., mice challenged with PVP did not develop IgG.

  8. Optical properties of PbS/PVP nanocomposites films

    NASA Astrophysics Data System (ADS)

    Patel, Mitesh H.; Chaudhuri, Tapas K.; Patel, Vaibhav K.; Shripathi, T.; Deshpande, U.

    2016-05-01

    PbS/Polyvinylpyrrolidone (PVP) nanocomposites films with different volume fraction of PbS have been deposited from single molecular precursors. X-ray diffraction patterns conforms the formation of PbS nanocrystals in PVP matrix. The transmission spectra of the films in the wavelength range of 300 to 2400 nm show the absorption edges are blue shifted due to formation of PbS Nanoparticles. The band gap determined are 2.4, 1.5 and 1.25 eV for PbS volume fraction of 8.5, 16, 27%, respectively. The corresponding refractive indices, n determined from Fresnel relation are 1.8, 2, and 2.35 which are in between that of PbS (4.2) and PVP (1.48).

  9. Formation of gold and silver nanostructures within polyvinylpyrollidone (PVP) gel

    SciTech Connect

    Kan Caixia; Wang Changshun; Zhu Jiejun; Li Hongchen

    2010-04-15

    Study on reduction of Au(III) and Ag(I) and the formation of Au and Ag nanostructures was performed on the gels of metal precursor and PVP polymer mixture. Some comparing samples were prepared for better understanding the role of reactants on the reduction of metal ions and further growth of nanocrystals. The results suggest that, in addition to its function of generating stable colloids, PVP not only has a reducing effect on metal ions, but also acts as a crystal growth modifier. At low temperatures, the reducing effect of PVP is strong on Ag(I) ions in AgNO{sub 3}, while the reduction of complex Au(III) ions in HAuCl{sub 4} is slow, involving two steps of Au(III)->Au(I)->Au. In the study of temperature disturbance on crystal growth, Au nanoplates of new and well-defined star shape were observed. The differences in the size and shape of nanoparticles are discussed from the colloid chemistry. - Graphical abstract: If a temperature difference was introduced to the gel of Au{sup 3+}(H{sub 2}O)-PVP, large sized Au nanoplates with new and well-defined star shape were observed.

  10. Synthesis and Conductometric Property of Sol-Gel-Derived ZnO/PVP Nano Hybrid Films

    NASA Astrophysics Data System (ADS)

    Ilegbusi, Olusegun J.; Trakhtenberg, Leonid

    2013-03-01

    ZnO nanoparticles immobilized in polyvinylpyrrolidone (PVP) were prepared using sol-gel dip-coating technique with varying Zn2+/PVP ratios. The films were characterized using atomic force microscopy, x-ray photoelectron spectroscopy, and Fourier transform infrared spectroscopy for chemical analysis. The size and concentration of ZnO particles decreased as the Zn/PVP ratio decreased. Under low Zn2+/PVP molar ratios, ZnO particles were clearly well separated and capped in the PVP polymer matrix. Electrical resistivity of 108 Ω cm was achieved under these deposition conditions.

  11. Polysulfone membranes. III. Performance evaluation of polyethersulfone-PVP membranes

    SciTech Connect

    Tam, C.M.; Matsuura, T.; Tweddle, T.A. ); Hazlett, J.D. )

    1993-12-01

    The performance of membranes produced from casting solutions consisting of polyethersulfone (PES), poly-(N-vinyl-pyrrolidone) (PVP), and N-methyl-2-pyrrolidinone (NMP) were systematically studied. Zero-shear casting solution viscosities for these polymer solutions were determined as a function of PES and PVP concentrations. Ultrafiltration membranes were then cast using the phase inversion technique and characterized by separation experiments using polyethylene glycols of various molecular weights as test solutes. A pore flow model was fitted to the resulting separation data to provide estimates of the average pore radius and membrane porosity. These parameters were used to compare laboratory results for this membrane casting solution system with performance data for commercially available polyethersulfone membranes. 15 refs., 4 figs., 1 tab.

  12. Synthesis of BiOBr-PVP hybrids with enhanced adsorption-photocatalytic properties

    NASA Astrophysics Data System (ADS)

    Li, Yanqing; Wang, Zeyan; Huang, Baibiao; Dai, Ying; Zhang, Xiaoyang; Qin, Xiaoyan

    2015-08-01

    We synthesized BiOBr-PVP hybrids by a simple solvothermal process, and investigated the adsorption and photocatalytic properties. Due to the presence of PVP, the thickness of the BiOBr nanosheets in BiOBr-PVP hybrids can be greatly reduced, which increased the percentage of highly reactive (0 0 1) facets exposed. And PVP was found to be adsorbed on the surface of BiOBr nanosheets by a strong donor-acceptor interactions via Cdbnd O bonds, which lead to an enhanced zeta potential and stronger adsorption capacity of cationic RhB molecules on the surface of BiOBr-PVP hybrids. And due to the synergistic effects of both high percentage of reactive (0 0 1) crystal facets and strong adsorption capacity, BiOBr-PVP hybrids exhibit excellent activities and stabilities on RhB dye degradation, which could be potentially used for practical waste water treatments.

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

    NASA Astrophysics Data System (ADS)

    Bobadilla, L. F.; García, C.; Delgado, J. J.; Sanz, O.; Romero-Sarria, F.; Centeno, M. A.; Odriozola, J. A.

    2012-11-01

    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.

  14. Electrospinning of PCL/PVP blends for tissue engineering scaffolds.

    PubMed

    Kim, Gyeong-Man; Le, Kim Huyen Trang; Giannitelli, Sara Maria; Lee, Yu Jin; Rainer, Alberto; Trombetta, Marcella

    2013-06-01

    Currently, one of the main drawbacks of using poly(ε-caprolactone) in the biomedical and pharmaceutical fields is represented by its low biodegradation rate. To overcome this limitation, electrospinning of PCL blended with a water-soluble poly(N-vinyl-2-pyrrolidone) was used to fabricate scaffolds with tunable fiber surface morphology and controllable degradation rates. Electrospun scaffolds revealed a highly immiscible blend state. The incorporated PVP phase was dispersed as inclusions within the electrospun fibers, and then easily extracted by immersing them in cell culture medium, exhibiting nanoporosity on the fiber surface. As a striking result, nanoporosity facilitated not only fiber biodegradation rates, but also improved cell attachment and spreading on the blend electrospun scaffolds. The present findings demonstrate that simultaneous electrospinning technique for PCL with water-soluble PVP provides important insights for successful tuning biodegradation rate for the PCL electrospun scaffolds but not limited to expand other high valuable biocompatible polymers for the future biomedical applications, ranging from tissue regeneration to controlled drug delivery. PMID:23468162

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

    PubMed

    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. PMID:26059285

  16. Twenty-One Cases Involving Alpha-Pyrrolidinovalerophenone (α-PVP).

    PubMed

    Wright, Trista Haupt; Harris, Chad

    2016-06-01

    Twenty-one cases involving alpha-pyrrolidinovalerophenone (α-PVP) were submitted between 2012 and 2015 to the Western Department of Forensic Science Laboratory. Eighteen suspected impaired driving cases were determined to have α-PVP concentrations <0.005-0.09 mg/L. Three fatalities during this period were determined to have α-PVP concentrations ranging from 0.03 to >20 mg/L. Human use of synthetic cathinones like α-PVP has been reported to induce psychological effects such as delusions, paranoia, hallucinations and deleterious cardiovascular effects. Quantitation was performed using a liquid-liquid extraction with detection by liquid chromatography triple quadrupole mass spectrometry using electrospray ionization in a multiple reaction monitoring mode. The reported behaviors in the 18 suspected impaired driving cases ranged from central nervous system depression to eluding officers in a high speed chase. The mean and median DUID α-PVP concentrations were both 0.030 mg/L. The α-PVP concentrations in the three fatalities were determined to be 0.033, 0.054 and present >20 mg/L. In 18 DUID cases, only 4 cases reported side effects consistent with synthetic cathinones. Two of the three fatalities indicated histories of bath salt and/or recreational drug use. At this time, no correlation can be determined between side effects and α-PVP concentrations. PMID:27185821

  17. Thermally stimulated nonlinear refraction in gelatin stabilized Cu-PVP nanocomposite thin films

    NASA Astrophysics Data System (ADS)

    Tamgadge, Y. S.; Atkare, D. V.; Pahurkar, V. G.; Talwatkar, S. S.; Sunatkari, A. L.; Muley, G. G.

    2016-05-01

    This article illustrates investigations on thermally stimulated third order nonlinear refraction of Cu-PVP nanocomposite thin films. Cu nanoparticles have been synthesized using chemical reduction method and thin films in PVP matrix have been obtained using spin coating technique. Thin films have been characterized by X-ray diffraction (XRD) and Ultraviolet-visible (UV-vis) spectroscopyfor structural and linear optical studies. Third order nonlinear refraction studies have been performed using closed aperture z-scan technique under continuous wave (CW) He-Ne laser. Cu-PVP nanocomposites are found to exhibit strong nonlinear refractive index stimulated by thermal lensing effect.

  18. Effect of solvent and PVP on electrode conductivity in laser-induced reduction process

    NASA Astrophysics Data System (ADS)

    Lee, Huseung; Yang, Minyang

    2015-04-01

    Laser sintering process is a promising technique which can sinter an electrode pattern selectively without mask. In this study, metal oxide nanoparticle with several solvents and various molar ratio of polyvinylpyrrolidone (PVP) is prepared to optimize a fabrication of a copper electrode pattern. As a result, the solvent with exothermic heat flow and low absorption cross-section shows better pattern shape and higher conductivity in selective laser sintering. Additionally, PVP, a reductant, affects to the quality of electrode, too. High molar ratio and large amount of PVP make the laser sintering process window broad and the specific resistivity low.

  19. DBS investigation on films of cobalt chloride doped PVA-PVP blend

    NASA Astrophysics Data System (ADS)

    Hammannavar, Preeti B.; Baraker, Basavarajeshwari M.; Bhajantri, R. F.; Ravindrachary, V.; Lobo, Blaise

    2015-06-01

    Films of Cobalt Chloride (CoCl2) doped polyvinylalcohol(PVA)- polyvinylpyrrolidone(PVP) blend (doped from 0.5 wt% up to 28 wt%) were prepared by solution casting, and characterized by XRD, DSC, UV-Visible Spectrometry TGA, FTIR and electrical measurements. In this paper, the results of Doppler Broadening Spectroscopy (DBS) in CoCl2 doped PVA-PVP blend is discussed. An increase in crystallinity of PVA-PVP blend, is observed, on doping it with CoCl2. The DBS results are complemented by XRD and DSC scans.

  20. Superovulation in ewes by a single injection of pFSH dissolved in polyvinylpyrrolidone (PVP): effects of PVP molecular weight, concentration and schedule of treatment.

    PubMed

    D'Alessandro, A G; Martemucci, G; Colonna, M A; Borghese, A; Terzano, M G; Bellitti, A

    2001-03-30

    Three experiments were carried out to evaluate induction in ewes of superovulation and embryo production by a single injection of a porcine pituitary extract (pFSH) dissolved in polyvinylpyrrolidone (PVP), investigating the effects of PVP molecular weight and its concentration (Experiment I), time and method of treatment (Experiments II and III). All ewes were synchronized for estrus by vaginal sponges impregnated with fluorogestone acetate (FGA; 30 mg, 9 days) plus PGF(2alpha) (Cloprostenol, 50 microg, 48h before sponge removal - s.r.), and superovulated by 250 IU pFSH. In Experiment I, 60 Gentile di Puglia ewes were subdivided into five experimental groups (n = 12): Group A, the control, received six decreasing intramuscular (i.m.) doses of pFSH, 12 h apart, beginning 48h before s.r.; Groups B and C were given 48 h before s.r. a single i.m. injection of pFSH dissolved in PVP with MW = 10,000, respectively, at concentrations of 15 and 30% w/v; Groups D and E received the same treatments as for B and C using PVP with MW = 40,000. None of the pFSH-PVP treatments were effective in inducing superovulation. In Experiment II, 22 Leccese ewes were subdivided into two groups (n = 11): Group A, control received i.m. four decreasing doses of pFSH, beginning 24 h before s.r., 12h apart; Group B was given a single i.m. injection of pFSH dissolved in PVP (MW = 40,000 at 30% w/v), 24 h before s.r. The pFSH-PVP treatment provided an ovulation rate similar to the control and tended to enhance embryo yield (4.4 versus 2.4, P>0.05). In Experiment III, 60 Leccese ewes were subdivided into six treatment groups (n = 10). Groups A and D served as controls and received i.m. 12 h apart, six doses (from 48 h before s.r.) and four doses (from 24h before s.r.) of pFSH, respectively. Groups B and C were treated by a single injection of pFSH in PVP (MW = 10,000; 30% w/v) 48 h before s.r., respectively by i.m. or subcutaneous (s.c.) administration. Groups E and F received the same treatments

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

    NASA Astrophysics Data System (ADS)

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

    2008-09-01

    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.

  2. Comparing various techniques to produce micro/nanoparticles for enhancing the dissolution of celecoxib containing PVP.

    PubMed

    Homayouni, Alireza; Sadeghi, Fatemeh; Varshosaz, Jaleh; Garekani, Hadi Afrasiabi; Nokhodchi, Ali

    2014-09-01

    One of the major challenges in pharmaceutical development is the poor dissolution performance of drugs. Celecoxib (CLX) is a poorly water soluble drug with its bioavailability being limited by its poor dissolution. In this study several particle engineering methods were employed on CLX using various ratios of CLX:PVP-K30. Micro/nanoparticles of CLX:PVP were prepared by using spray drying (SD), antisolvent crystallization followed by freeze drying (CRS-FD) and spray drying (CRS-SD) techniques. The suspension obtained through antisolvent crystallization was also subjected to high pressure homogenization followed by freeze drying (HPH-FD). Particle size measurements, saturation solubility, optical and scanning electron microscopy, DSC, XRPD, FT-IR and dissolution test were performed to characterize the physicochemical and pharmaceutical properties of the samples. The results showed that spray dried samples in the presence of (50%) PVP produced spherical particles and exhibited a high dissolution rate. Interestingly in the antisolvent crystallization technique, spherical nanoparticles of drug-PVP were obtained in the range of 291-442 nm. The average particle size was dependent on the concentration of the PVP used during the crystallization process. Solid state analysis showed that these particles were completely amorphous in nature. Also interesting to note was that at concentration of 5% PVP, when the suspension of nanoparticles was subjected to the high pressure homogenization process, the crystallinity of CLX increased. Despite the partial crystallinity of particles produced, they showed excellent dissolution behavior. It can thus be concluded that the method of preparation of CLX micro/nanoparticles had a big impact on the dissolution rate when the concentration of PVP was low (e.g., 5%). At high PVP concentration (e.g., 50%) all methods used to prepare engineered CLX particles showed better dissolution with no significant differences in their dissolution

  3. The immunotoxicity of graphene oxides and the effect of PVP-coating.

    PubMed

    Zhi, Xiao; Fang, Hongliang; Bao, Chenchen; Shen, Guangxia; Zhang, Jiali; Wang, Kan; Guo, Shouwu; Wan, Tao; Cui, Daxiang

    2013-07-01

    Graphene oxide (GO) immunotoxicity is not clarified well up to date. Herein we reported the effects of GOs with and without polyvinylpyrrolidone (PVP) coating on human immune cells such as dendritic cells (DCs), T lymphocytes and macrophages. Human immune cells such as dendritic cells (DCs), T lymphocytes and macrophages were isolated from health donated bloods, PVP-coating GO (PVP-GO) exhibited lower immunogenicity compared with pure GO on the aspect of inducing differentiation and maturation of dendritic cells (DCs), the levels of secreted TNF-α and IL-1β had no obvious difference between two groups, yet the secretion of IL-6 remained in PVP-coating GO group. In addition, PVP-coating GO delayed significantly the apoptotic process of T lymphocytes, at the same time, and exhibited anti-phagocytosis ability against macrophages and markedly enhanced the physiological activity of macrophages. In conclusion, PVP-coating GO possesses good immunological biocompatibility and immunoenhancement effects in vitro, and is likely to be an available candidate of immunoadjuvant in the future. PMID:23566800

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

    PubMed

    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. PMID:26606378

  5. Cysteine could change the transport mechanism of PVP-coated silver nanoparticles in porous media

    NASA Astrophysics Data System (ADS)

    Yang, X.; Lin, S.; Wiesner, M.

    2012-12-01

    Silver nanoparticles (AgNPs) can hardly be removed by wastewater treatment plant and have big potential to enter groundwater, jeopardizing the water quality & aquatic ecosystem. Most AgNPs have surface coatings such as polyvinylpyrrolidone (PVP) which dominate their transport in porous media. Our previous study shows that PVP may promote the deposition of AgNPs on silica surface by a bridging mechanism. This study further explored how cysteine, a natural organic matter type, may influence the role of the PVP coating on AgNP translocation. Dynamic Light Scattering (DLS) measurement (Figure 1A) shows that the PVP coating rendered the AgNP dispersion high stability during the measuring period (3hrs). Addition of 100 ppm cysteine to the dispersion resulted in a rapid decrease in particle size from 100nm to 52nm within one hour, following which no further decline in particle size occurred. Column experiment results (Figure 1B) show that corresponding to the particle size change was a substantial decrease in particle deposition rates: introduction of 100 ppm cysteine into the particle dispersion resulted in a decrease in AgNP attenuation by the porous medium from 67% to 26%. The decline in particle size suggested that cysteine may have displaced the macromolecular PVP from the particle surface. Desorption of PVP resulted in a weakening or vanish of polymer bridging effect which in turn lowered the deposition rates substantially. This study demonstrated an implication of environmental transformation of coated AgNPs to their mobility in saturated sand aquifers. Acknowledgment Xinyao Yang appreciates the Natural Science Foundation of China (Grant No.:41101475) for covering the registration fee and traveling costs.igure 1 Particle size measurement (A) and breakthrough curves (B) of PVP-coated silver nanoparticle in the absence and presence of cysteine: pH=7.0, ionic strength=1mM, flow rate=1ml/min.

  6. Measurement of clay surface areas by polyvinylpyrrolidone (PVP) sorption and its use for quantifying illite and smectite abundance

    USGS Publications Warehouse

    Blum, A.E.; Eberl, D.D.

    2004-01-01

    A new method has been developed for quantifying smectite abundance by sorbing polyvinylpyrrolidone (PVP) on smectite particles dispersed in aqueous solution. The sorption density of PVP-55K on a wide range of smectites, illites and kaolinites is ???0.99 mg/m2, which corresponds to ???0.72 g of PVP-55K per gram of montmorillonite. Polyvinylpyrrolidone sorption on smectites is independent of layer charge and solution pH. PVP sorption on Si02, Fe 2O3 and ZnO normalized to the BET surface area is similar to the sorption densities on smectites. ??-Al 2O3, amorphous Al(OH)3 and gibbsite have no PVP sorption over a wide range of pH, and sorption of PVP by organics is minimal. The insensitivity of PVP sorption densities to mineral layer charge, solution pH and mineral surface charge indicates that PVP sorption is not localized at charged sites, but is controlled by more broadly distributed sorption mechanisms such as Van der Waals' interactions and/or hydrogen bonding. Smectites have very large surface areas when dispersed as single unit-cell-thick particles (???725 m2/g) and usually dominate the total surface areas of natural samples in which smectites are present. In this case, smectite abundance is directly proportional to PVP sorption. In some cases, however, the accurate quantification of smectite abundance by PVP sorption may require minor corrections for PVP uptake by other phases, principally illite and kaolinite. Quantitative XRD can be combined with PVP uptake measurements to uniquely determine the smectite concentration in such sample. ?? 2004, The Clay Minerals Society.

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

    PubMed

    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. PMID:24374324

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

    NASA Astrophysics Data System (ADS)

    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).

  9. Biodegradation of PVP-CMC hydrogel film: a useful food packaging material.

    PubMed

    Roy, Niladri; Saha, Nabanita; Kitano, Takeshi; Saha, Petr

    2012-06-20

    Hydrogels can offer new opportunities for the design of efficient packaging materials with desirable properties (i.e. durability, biodegradability and mechanical strength). It is a promising and emerging concept, as most of the biopolymer based hydrogels are supposed to be biodegradable, they can be considered as alternative eco-friendly packaging materials. This article reports about synthetic (polyvinylpyrrolidone (PVP)) and biopolymer (carboxymethyl cellulose (CMC)) based a novel hydrogel film and its nature of biodegradability under controlled environmental condition. The dry hydrogel films were prepared by solution casting method and designated as 'PVP-CMC hydrogel films'. The hydrogel film containing PVP and CMC in a ratio of 20:80 shows best mechanical properties among all the test samples (i.e. 10:90, 20:80, 50:50, 80:20 and 90:10). Thus, PVP-CMC hydrogel film of 20:80 was considered as a useful food packaging material and further experiments were carried out with this particular hydrogel film. Biodegradation of the PVP-CMC hydrogel films were studied in liquid state (Czapec-Dox liquid medium+soil extracts) until 8 weeks. Variation in mechanical, viscoelastic properties and weight loss of the hydrogel films with time provide the direct evidence of biodegradation of the hydrogels. About 38% weight loss was observed within 8 weeks. FTIR spectra of the hydrogel films (before and after biodegradation) show shifts of the peaks and also change in the peak intensities, which refer to the physico-chemical change in the hydrogel structure and SEM views of the hydrogels show how internal structure of the PVP-CMC film changes in the course of biodegradation. PMID:24750729

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

    PubMed

    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. PMID:26247119

  11. PVP capped CdS nanoparticles for UV-LED applications

    SciTech Connect

    Sivaram, H.; Selvakumar, D.; Jayavel, R.

    2015-06-24

    Polyvinlypyrrolidone (PVP) capped cadmium sulphide (CdS) nanoparticles are synthesized by wet chemical method. The powder X-ray diffraction (XRD) result indicates that the nanoparticles are crystallized in cubic phase. The optical properties are characterized by UV-Vis absorption. The morphology of CdS nanoparticles are studied using Scanning electron microscope (SEM). The thermal behavior of the as prepared nanoparticles has been examined by Thermo gravimetric analysis (TGA). The optical absorption study of pvp capped CdS reveal a red shift confirms the UV-LED applications.

  12. Characterization and stability of ternary solid dispersions with PVP and PHPMA.

    PubMed

    Al-Obaidi, Hisham; Ke, Peng; Brocchini, Steve; Buckton, Graham

    2011-10-31

    The effect of adding a third polymer to immiscible binary solid dispersions was investigated. The model actives griseofulvin (GF), progesterone (PG) and phenindione (PD) were selected because they exemplify a key property of many poorly soluble molecules of having at least one hydrogen bonding acceptor moiety while not having any hydrogen bond donating moieties. Ternary solid dispersions of the drug, PVP (polyvinylpyrrolidone) (proton acceptor) and PHPMA (poly[2-hydroxypropyl methacrylate]) (proton acceptor and donor) were prepared by spray drying. Stability results showed that binary solid dispersions (API and PVP) of GF and PVP crystallized quickly while the amorphous form was not possible to prepare for PG and PD. The amorphous form was prolonged upon the incorporation of PHPMA in the solid dispersion (API, PHPMA and PVP). Based on measuring the melting points, the energy of mixing the drug with the polymer was calculated using the Flory-Huggins theory. The results showed that GF had the lowest free energy followed by PG and finally PD which agreed well with the stability results. These results suggest that the addition of a third polymer to immiscible binary solid dispersions can significantly improve the stability of the amorphous form. PMID:21801822

  13. Photoluminescence study of PVP capped CdS nanoparticles embedded in PVA matrix

    SciTech Connect

    Pattabi, Manjunatha . E-mail: manjupattabi@yahoo.com; Saraswathi Amma, B.; Manzoor, K.

    2007-05-03

    Photoluminescence properties of polyvinyl pyrrolidone (PVP) capped cadmium sulphide (CdS) nanoparticles embedded in polyvinyl alcohol matrix (PVA) are reported. The PVP-CdS nanoparticles are prepared by non-aqueous method wherein cadmium nitrate is used as the cadmium source and hydrogen sulphide as the sulphur source. The synthesized nanoparticles are dispersed in polyvinyl alcohol (PVA) matrix and cast as self-standing flexible (PVP-CdS)-PVA films. The nanocomposites are characterized by optical absorption spectroscopy, X-ray diffraction (XRD) and transmission electron microscopy (TEM) studies. XRD and TEM studies show the formation of cubic CdS particles with average size {approx}3-5 nm. Thermal studies, carried out to observe the changes in PVA matrix due to the incorporation of PVP-CdS nanoparticles show strong interaction between the polymer matrix and nanoparticles. The photoluminescence emission spectra of the nanocomposites show two peaks, at 502 and 636 nm, which are attributed to the band edge and surface defects respectively, of CdS nanoparticles. Effective surface capping with optimum concentration of polyvinyl pyrrolidone leads to the quenching of surface defect-related emission.

  14. Optical, magnetic and electrical properties of multifunctional Cr3+: Polyethylene oxide (PEO) + polyvinylpyrrolidone (PVP) polymer composites

    NASA Astrophysics Data System (ADS)

    Naveen Kumar, K.; Rao, J. L.; Ratnakaram, Y. C.

    2015-11-01

    Multifunctional polymer composite films of PEO + PVP and also doped with Cr3+ ions in different concentrations have been synthesized by a solution casting method. The semi-crystalline nature of the polymer films was confirmed by XRD studies. Raman spectral analysis confirms the complex formation of the polymer with dopant ions. The optical absorption spectrum of Cr3+ doped polymer exhibits three absorption bands pertaining to Cr3+ ions in octahedral symmetry. From the absorption spectrum, Racah parameters were evaluated. The red emission at 614 nm (4T2g→4A2g) has been observed for the Cr3+: PEO + PVP polymer under the UV excitation. EPR spectra of Cr3+ ions doped polymers at different concentrations of Cr3+ ions exhibit resonance signals which are characteristic of Cr3+ ions in the octahedral symmetry. Cr3+: PEO + PVP revealed the superparamagnetic nature based on the trends on Vibrational Sample Magnetometer profiles. Cr3+(0.1 wt%): PEO + PVP polymer reveals high ionic conductivity in the order of 1.14 × 10-5 S/cm at 373 K. Dielectric constant behaviour has also been analysed with respect to frequency.

  15. Molecular Characterization of the Mycoplasma gallisepticum pvpA Gene Which Encodes a Putative Variable Cytadhesin Protein

    PubMed Central

    Boguslavsky, S.; Menaker, D.; Lysnyansky, I.; Liu, T.; Levisohn, S.; Rosengarten, R.; García, M.; Yogev, D.

    2000-01-01

    A putative cytadhesin-related protein (PvpA) undergoing variation in its expression was identified in the avian pathogen Mycoplasma gallisepticum. The pvpA gene was cloned, expressed in Escherichia coli, and sequenced. It exhibits 54 and 52% homology with the P30 and P32 cytadhesin proteins of the human pathogens Mycoplasma pneumoniae and Mycoplasma genitalium, respectively. In addition, 50% homology was found with the MGC2 cytadhesin of M. gallisepticum and 49% homology was found with a stretch of 205 amino acids of the cytadherence accessory protein HMW3 of M. pneumoniae. The PvpA molecule possesses a proline-rich carboxy-terminal region (28%) containing two identical directly repeated sequences of 52 amino acids and a tetrapeptide motif (Pro-Arg-Pro-X) which is repeated 14 times. Genetic analysis of several clonal isolates representing different expression states of the PvpA product ruled out chromosomal rearrangement as the mechanism for PvpA phase variation. The molecular basis of PvpA variation was revealed in a short tract of repeated GAA codons, encoding five successive glutamate resides, located in the N-terminal region and subject to frequent mutation generating an in-frame UAA stop codon. Size variation of the PvpA protein was observed among M. gallisepticum strains, ranging from 48 to 55 kDa and caused by several types of deletions occurring at the PvpA C-terminal end and within the two directly repeated sequences. By immunoelectron microscopy, the PvpA protein was localized on the mycoplasma cell surface, in particular on the terminal tip structure. Collectively, these findings suggest that PvpA is a newly identified variable surface cytadhesin protein of M. gallisepticum. PMID:10858209

  16. Molecular characterization of the Mycoplasma gallisepticum pvpA gene which encodes a putative variable cytadhesin protein.

    PubMed

    Boguslavsky, S; Menaker, D; Lysnyansky, I; Liu, T; Levisohn, S; Rosengarten, R; García, M; Yogev, D

    2000-07-01

    A putative cytadhesin-related protein (PvpA) undergoing variation in its expression was identified in the avian pathogen Mycoplasma gallisepticum. The pvpA gene was cloned, expressed in Escherichia coli, and sequenced. It exhibits 54 and 52% homology with the P30 and P32 cytadhesin proteins of the human pathogens Mycoplasma pneumoniae and Mycoplasma genitalium, respectively. In addition, 50% homology was found with the MGC2 cytadhesin of M. gallisepticum and 49% homology was found with a stretch of 205 amino acids of the cytadherence accessory protein HMW3 of M. pneumoniae. The PvpA molecule possesses a proline-rich carboxy-terminal region (28%) containing two identical directly repeated sequences of 52 amino acids and a tetrapeptide motif (Pro-Arg-Pro-X) which is repeated 14 times. Genetic analysis of several clonal isolates representing different expression states of the PvpA product ruled out chromosomal rearrangement as the mechanism for PvpA phase variation. The molecular basis of PvpA variation was revealed in a short tract of repeated GAA codons, encoding five successive glutamate resides, located in the N-terminal region and subject to frequent mutation generating an in-frame UAA stop codon. Size variation of the PvpA protein was observed among M. gallisepticum strains, ranging from 48 to 55 kDa and caused by several types of deletions occurring at the PvpA C-terminal end and within the two directly repeated sequences. By immunoelectron microscopy, the PvpA protein was localized on the mycoplasma cell surface, in particular on the terminal tip structure. Collectively, these findings suggest that PvpA is a newly identified variable surface cytadhesin protein of M. gallisepticum. PMID:10858209

  17. The Maturation Process of pVP2 Requires Assembly of Infectious Bursal Disease Virus Capsids

    PubMed Central

    Chevalier, Christophe; Lepault, Jean; Erk, Inge; Da Costa, Bruno; Delmas, Bernard

    2002-01-01

    Infectious bursal disease virus (IBDV) is a nonenveloped avian virus with a two-segment double-stranded RNA genome. Its T=13 icosahedral capsid is most probably assembled with 780 subunits of VP2 and 600 copies of VP3 and has a diameter of about 60 nm. VP1, the RNA-dependent RNA polymerase, resides inside the viral particle. Using a baculovirus expression system, we first observed that expression of the pVP2-VP4-VP3 polyprotein encoded by the genomic segment IBDA results mainly in the formation of tubules with a diameter of about 50 nm and composed of pVP2, the precursor of VP2. Very few virus-like particles (VLPs) and VP4 tubules with a diameter of about 25 nm were also identified. The inefficiency of VLP assembly was further investigated by expression of additional IBDA-derived constructs. Expression of pVP2 without any other polyprotein components results in the formation of isometric particles with a diameter of about 30 nm. VLPs were observed mainly when a large exogeneous polypeptide sequence (the green fluorescent protein sequence) was fused to the VP3 C-terminal domain. Large numbers of VLPs were visualized by electron microscopy, and single particles were shown to be fluorescent by standard and confocal microscopy analysis. Moreover, the final maturation process converting pVP2 into the VP2 mature form was observed on generated VLPs. We therefore conclude that the correct scaffolding of the VP3 can be artificially induced to promote the formation of VLPs and that the final processing of pVP2 to VP2 is controlled by this particular assembly. To our knowledge, this is the first report of the engineering of a morphogenesis switch to control a particular type of capsid protein assembly. PMID:11836416

  18. Sustained release of diltiazem HCl tableted after co-spray drying and physical mixing with PVAc and PVP.

    PubMed

    Al-Zoubi, Nizar; Al-Obaidi, Ghada; Tashtoush, Bassam; Malamataris, Stavros

    2016-01-01

    In this work, aqueous diltiazem HCl and polyvinyl-pyrrolidone (PVP) solutions were mixed with Kollicoat SR 30D and spray dried to microparticles of different drug:excipient ratio and PVP content. Co-spray dried products and physical mixtures of drug, Kollidon SR and PVP were tableted. Spray drying process, co-spray dried products and compressibility/compactability of co-spray dried and physical mixtures, as well as drug release and water uptake of matrix-tablets was evaluated. Simple power equation fitted drug release and water uptake (R(2) > 0.909 and 0.938, respectively) and correlations between them were examined. Co-spray dried products with PVP content lower than in physical mixtures result in slower release, while at equal PVP content (19 and 29% w/w of excipient) in similar release (f2 > 50). Increase of PVP content increases release rate and co-spray drying might be an alternative, when physical mixing is inadequate. Co-spray dried products show better compressibility/compatibility but higher stickiness to the die-wall compared to physical mixtures. SEM observations and comparison of release and swelling showed that distribution of tableted component affects only the swelling, while PVP content for both co-spray dried and physical mixes is major reason for release alterations and an aid for drug release control. PMID:26035331

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

    PubMed

    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. PMID:23483432

  20. Microstructural and electrical properties of PVA/PVP polymer blend films doped with cupric sulphate

    NASA Astrophysics Data System (ADS)

    Hemalatha, K.; Mahadevaiah, Gowtham, G. K.; Urs, G. Thejas; Somashekarappa, H.; Somashekar, R.

    2016-05-01

    A series of polyvinyl alcohol (PVA)/polyvinyl pyrrolidone (PVP) polymer blends added with different concentrations of cupric sulphate (CuSO4) were prepared by solution casting method and were subjected to X-ray diffraction (XRD) and Ac conductance measurements. An attempt has been made to study the changes in crystal imperfection parameters in PVA/PVP blend films with the increase in concentration of CuSO4. Results show that decrease in micro crystalline parameter values is accompanied with increase in the amorphous content in the film which is the reason for film to have more flexibility, biodegradability and good ionic conductivity. AC conductance measurements in these films show that the conductivity increases as the concentration of CuSO4 increases. These films were suitable for electro chemical applications.

  1. Microstructural and electrical properties of CoCl2 doped HPMC/PVP polymer blend films

    NASA Astrophysics Data System (ADS)

    Somashekarappa, H.; Prakash, Y.; Mahadevaiah, Hemalatha, K.; Somashekar, R.

    2013-02-01

    Solid polymer electrolyte (SPE) based on Hydroxypropylemethylcellulose (HPMC) and Polyvinylpyrrolidone (PVP) polymer blend films complexed with different weight ratio of CoCl2 were prepared using solution casting method and investigated using X-ray line profile analysis. An attempt has been made to study the changes in crystal imperfection parameters in HPMC/PVP blend films with the increase in concentration of CoCl2. Results show that decrease in micro crystalline parameter values is accompanied with increase in the amorphous content in the film which is the reason for film to have more flexibility, biodegradability and good ionic conductivity. AC conductivity measurements in these films show that the conductivity increases as the concentration of CoCl2 increases. These films were suitable for electro chemical applications.

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

    NASA Astrophysics Data System (ADS)

    Fan, Tao; Li, Yinle; Shen, Jianfeng; Ye, Mingxin

    2016-03-01

    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 (Eg = 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.

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

    NASA Astrophysics Data System (ADS)

    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.

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

    PubMed

    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. PMID:27237056

  5. Synthesis of PVP-stabilized ruthenium colloids with low boiling point alcohols.

    PubMed

    Zhang, Yuqing; Yu, Jiulong; Niu, Haijun; Liu, Hanfan

    2007-09-15

    A route to the preparation of poly(N-vinyl-2-pyrrolidone) (PVP)-stabilized ruthenium colloids by refluxing ruthenium(III) chloride in low boiling point alcohols was developed. Deep purple colloids with shuttle-like ruthenium particles were also synthesized. XPS measurement verified the nanoparticles were in the metallic state. The morphology of metal nanoparticles was characterized by UV-visible absorption spectrophotometry, TEM and XRD. PMID:17568601

  6. Co-precipitation with PVP and Agar to Improve Physicomechanical Properties of Ibuprofen

    PubMed Central

    Maghsoodi, Maryam; Kiafar, Farhad

    2013-01-01

    Objective(s) : Ibuprofen is a problematic drug in tableting due to its viscoelastic properties. Additionally its high cohesivity results in low flowability. In this study, co-precipitation of ibuprofen with varying concentration of agar and PVP to optimize properties of Ibuprofen was carried out. Materials and Methods: Co-precipitates of ibuprofen- PVP or agar were prepared by solvent evaporation technique under vacuum condition. Differential scanning calorimetry (DSC), X -ray diffraction of powder (XRDP) and FT-IR spectroscopy were used to investigate the solid state characteristics of the co-precipitates. The dissolution behavior, flowability, particle size and compaction properties of various batches were also studied. Results: Co-precipitation of drug with agar led to a change in habit from needle to plate shape crystals, while drug –PVP co-precipitates had agglomerated structure and consisted of numerous crystals which had been aggregated together. The co-precipitates showed improved flow properties compared with ibuprofen alone. Precipitation of ibuprofen with these additives led to modification in the dissolution of the drug. Agar in 1% w/w improved slightly the dissolution rate of drug while PVP had a negative impact and led to reduction in the dissolution rate of drug to less than that of pure drug. The all obtained co-precipitates exhibited significantly improved tableting behavior compared with drug crystals alone. This may be due to this fact that, the polymer covering the drug particles increases and changes the nature of the surface area available for interparticulate bonds between particles. DSC, XRDP and FT-IR experiments showed that drug particles, in co-precipitates samples, did not undergo polymorphic modifications. Conclusion: The study highlights the influence of polymeric additives on crystallization process leading to modified performance. PMID:24250942

  7. Co-precipitation with PVP and Agar to Improve Physicomechanical Properties of Ibuprofen

    PubMed Central

    Maghsoodi, Maryam; Kiafar, Farhad

    2013-01-01

    Objective(s) : Ibuprofen is a problematic drug in tableting due to its viscoelastic properties. Additionally its high cohesivity results in low flowability. In this study, co-precipitation of ibuprofen with varying concentration of agar and PVP to optimize properties of Ibuprofen was carried out. Materials and Methods: Co-precipitates of ibuprofen- PVP or agar were prepared by solvent evaporation technique under vacuum condition. Differential scanning calorimetry (DSC), X -ray diffraction of powder (XRDP) and FT-IR spectroscopy were used to investigate the solid state characteristics of the co-precipitates. The dissolution behavior, flowability, particle size and compaction properties of various batches were also studied. Results: Co-precipitation of drug with agar led to a change in habit from needle to plate shape crystals, while drug –PVP co-precipitates had agglomerated structure and consisted of numerous crystals which had been aggregated together. The co-precipitates showed improved flow properties compared with ibuprofen alone. Precipitation of ibuprofen with these additives led to modification in the dissolution of the drug. Agar in 1% w/w improved slightly the dissolution rate of drug while PVP had a negative impact and led to reduction in the dissolution rate of drug to less than that of pure drug. The all obtained co-precipitates exhibited significantly improved tableting behavior compared with drug crystals alone. This may be due to this fact that, the polymer covering the drug particles increases and changes the nature of the surface area available for interparticulate bonds between particles. DSC, XRDP and FT-IR experiments showed that drug particles, in co-precipitates samples, did not undergo polymorphic modifications. Conclusion: The study highlights the influence of polymeric additives on crystallization process leading to modified performance. PMID:24250936

  8. Morphology, absorptivity and viscoelastic properties of mineralized PVP-CMC hydrogel

    NASA Astrophysics Data System (ADS)

    Saha, Nabanita; Shah, Rushita; Vyroubal, Radek; Kitano, Takeshi; Saha, Petr

    2013-04-01

    A simple liquid diffusion mineralization technique was applied for the incorporation of calcium carbonate (CaCO3) in PVP-CMC hydrogel. The hydrogel was prepared 6.5 mm thick to achieve around 1 mm thick sample after mineralization of hydrogel matrix with calcite. The calcite crystals were round shaped and organized as building blocks inside the porous three dimensional cross linked structure of the PVP-CMC hydrogel. The present study was designed to evaluate the properties of mineralized (calcite) hydrogel with respect to freshly prepared hydrogel and those swelled in water (H2O) after drying. The viscoelastic properties of swelled and mineralized samples were reported though the dry PVP-CMC hydrogel were swelled and mineralized with calcite until 150 min. It is observed that there is not much difference in elastic property of fresh and 60 min mineralized hydrogels but the values of elastic property are decreased in the case of swelled hydrogels. It is interesting that in case of swelled samples the values of complex viscosity (η*) are increased with the increase of swelling time after 90 min but in case of calcite hydrogel the values (η*) are gradually decreased with the increase of time.

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

    PubMed

    Abd El-Hady, Abeer; Abd El-Rehim, Hassan A

    2004-01-01

    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%. PMID:15467162

  10. PEDOT gate electrodes with PVP/Al2O3 dielectrics for stable high-performance organic TFTs

    NASA Astrophysics Data System (ADS)

    Lee, Young Kyu; Maniruzzaman, Md.; Lee, Chiyoung; Lee, Mi Jung; Lee, Eun-Gu; Lee, Jaegab

    2013-11-01

    A poly(3,4-ethylenedioxythiophene) (PEDOT) gate electrode on a polyestersulfone (PES) substrate was used to fabricate inverted staggered pentacene organic thin film transistors (OTFTs). The PEDOT gate formed on the PES substrate exhibited semi-transparency, high conductivity, and excellent adhesion to the substrate. Prior to the deposition of poly-4-vinyl phenol (PVP) dielectrics, a thin Al2O3 layer (12 nm) was coated onto a PEDOT electrode, providing an effective barrier against inter-diffusion between the PVP dielectrics and the underlying PEDOT gate electrode, and against moisture penetration through the PES substrate. This led to stable high-performance OTFTs consisting of a PEDOT gate electrode and PVP/Al2O3 dielectrics. The combined PVP/Al2O3 dielectrics with PEDOT gate electrodes were successfully implemented in flexible organic TFTs that exhibit excellent compatibility with flexible electronics.

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

    NASA Astrophysics Data System (ADS)

    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.

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

    NASA Astrophysics Data System (ADS)

    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.

  13. PVP formulated Fullerene (C60) increases Rho-kinase dependent Vascular Tissue Contractility in Pregnant Sprague Dawley Rats

    PubMed Central

    Vidanapathirana, Achini K.; Thompson, Leslie C.; Mann, Erin. E.; Odom, Jillian T.; Holland, Nathan A.; Sumner, Susan J.; Han, Li; Lewin, Anita H.; Fennell, Timothy R.; Brown, Jared M.; Wingard, Christopher J.

    2014-01-01

    Pregnancy is a unique physiological state, in which C60 fullerene is reported to be distributed in both maternal and fetal tissues. Tissue distribution of C60 differs between pregnant and non-pregnant states, presumably due to functional changes in vasculature during pregnancy. We hypothesized that, polyvinylpyrorrolidone (PVP) formulated C60 (C60/PVP) increases vascular tissue contractility during pregnancy by increasing Rho-kinase activity. C60/PVP was administered intravenously to pregnant and non-pregnant female Sprague Dawley rats. Vascular responses were assessed using wire myography 24 hours post-exposure. Increased stress generation was observed in uterine artery, thoracic aorta and umbilical vein. Rho-Rho-kinase mediated force maintenance was increased in arterial segments from C60/PVP exposed pregnant rats when compared to PVP exposed rats. Our findings suggest that intravenous exposure to C60/PVP during pregnancy increases vascular tissue contractility of the uterine artery through elements of Rho-Rho-kinase signaling during late stages of pregnancy. PMID:25088243

  14. Effect of incorporated PVP/Ag nanoparticles on ZnPc/C60 organic solar cells.

    PubMed

    Heo, Ilsu; Kim, Jinhyun; Yim, Sanggyu

    2013-06-01

    Various sizes of PVP-capped Ag nanoparticles were incorporated in the PEDOT:PSS layer of ZnPc/C60-based small-molecule organic solar cells. The incorporated nanoparticles partially block the incident light, but this was offset by the scattering effect and consequent increase in path lengths through the active organic layers. As a result, the overall power conversion efficiency of the cell increased by approximately 15% when nanoparticles with an average diameter of 24 nm were used. PMID:23862493

  15. PVP induce self-seeding process for growth of Au@Ag core@shell nanocomposites

    NASA Astrophysics Data System (ADS)

    Eisa, Wael H.; Al-Ashkar, Emad; El-Mossalamy, S. M.; Ali, Safaa S. M.

    2016-05-01

    A novel self-seeding route is developed for fabrication of metallic nanocomposites of gold (core) and silver (shell) (Au@Ag core@shell). Herein, polyvinylpyrrolidone (PVP) is used as both reducing and stabilizing agent. The surface plasmon resonance (SPR) of Au@Ag core@shell can be tuned by controlling the thickness of the Ag shell. The different growth stages of the Au@Ag core@shell have been traced by in situ UV-vis absorption spectra. Transmission electron microscopy (TEM), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy are used for the characterization of the prepared samples.

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

    NASA Astrophysics Data System (ADS)

    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.

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

    PubMed

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

    2014-01-01

    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. PMID:25486246

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

    NASA Astrophysics Data System (ADS)

    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.

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

    NASA Astrophysics Data System (ADS)

    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.

  20. Size Control of (99m)Tc-tin Colloid Using PVP and Buffer Solution for Sentinel Lymph Node Detection.

    PubMed

    Kim, Eun-Mi; Lim, Seok Tae; Sohn, Myung-Hee; Jeong, Hwan-Jeong

    2015-06-01

    Colloidal particle size is an important characteristic that allows mapping sentinel nodes in lymphoscintigraphy. This investigation aimed to introduce different ways of making a (99m)Tc-tin colloid with a size of tens of nanometers. All agents, tin fluoride, sodium fluoride, poloxamer-188, and polyvinylpyrrolidone (PVP), were mixed and labeled with (99m)Tc. Either phosphate or sodium bicarbonate buffers were used to adjust the pH levels. When the buffers were added, the size of the colloids increased. However, as the PVP continued to increase, the size of the colloids was controlled to within tens of nanometers. In all samples, phosphate buffer added PVP (30 mg) stabilized tin colloid ((99m)Tc-PPTC-30) and sodium bicarbonate solution added PVP (50 mg) stabilized tin colloid ((99m)Tc-BPTC-50) were chosen for in vitro and in vivo studies. (99m)Tc-BPTC-50 (<20 nm) was primarily located in bone marrow and was then secreted through the kidneys, and (99m)Tc-PPTC-30 (>100 nm) mainly accumulated in the liver. When a rabbit was given a toe injection, the node uptake of (99m)Tc-PPTC-30 decreased over time, while (99m)Tc-BPTC-50 increased. Therefore, (99m)Tc-BPTC-50 could be a good candidate radiopharmaceutical for sentinel node detection. The significance of this study is that nano-sized tin colloid can be made very easily and quickly by PVP. PMID:26028937

  1. The labeling of stem cells by superparamagnetic iron oxide nanoparticles modified with PEG/PVP or PEG/PEI.

    PubMed

    Yang, Gao; Ma, Weiqiong; Zhang, Baolin; Xie, Qi

    2016-05-01

    Poly(ethylene glycol) (PEG) and poly(vinyl pyrrolidone) (PVP) co-modified superparamagnetic iron oxide nanoparticles (SPIONs) (PEG/PVP-SPIONs), and PEG and poly(ethylene imine) (PEI) co-modified SPIONs (PEG/PEI-SPIONs) synthesized by thermal decomposition have been used as magnetic resonance imaging (MRI) contrast agents to label adipose-derived stem cells (ADSCs). Efficient cell labeling was achieved after incubation with PEG/PVP-SPIONs and PEG/PEI-SPIONs for 12h, and the MRI of labeled cells was evaluated. The cell viability tests showed the low cytotoxicity of PEG/PVP-SPIONs and PEG/PEI-SPIONs. The cellular iron content incubated with PEG/PVP-SPIONs at a concentration of 25 μg/ml was 6.96 pg/cell, the cellular iron contents incubated with PEG/PEI-SPIONs at concentrations of 12 and 25 μg/ml were 20.16, 35.4 pg/cell, respectively. The SPIONs were located predominantly in the intracellular vesicles. The cellular iron oxide uptake was significantly high after incubation with PEG/PEI-SPIONs as compared with the commercial iron oxide agents (Feridex, Feridex@PLL, Resovist and Resovist@PLL) reported. This work demonstrates that PEG/PEI-SPIONs are the competent agents for the labeling of ADSCs. PMID:26952437

  2. Measurement of fundamental illite particle thicknesses by X-ray diffraction using PVP-10 intercalation

    USGS Publications Warehouse

    Eberl, D.D.; Nuesch, R.; Sucha, V.; Tsipursky, S.

    1998-01-01

    The thicknesses of fundamental illite particles that compose mixed-layer illite-smectite (I-S) crystals can be measured by X-ray diffraction (XRD) peak broadening techniques (Bertaut-Warren-Averbach [BWA] method and integral peak-width method) if the effects of swellinf and XRD background noise are eliminated from XRD patterns of the clays. Swelling is eliminated by intercalating Na-saturated I-S with polyvinylpyrrolidone having a molecular weightof 10,000 (PVP-10). Background is minimized by using polished metallic silicon wafers cut perpendicular to (100) as a substrate for XRD specimens, and by using a single-crystal monochromator. XRD measurements of PVP-intercalated diagenetic, hydro-thermal and low-grade metamorphic I-S indicate that there at least 2 type of crystallite thickness distribution shapes for illite fundamental particles, lognormal and asymptotic; that measurements of mean fundamental illite particle thicknesses made by various techniques (Bertaut-Warren-Averbach, integral peak width, fixed cation content, and transmission electron microscopy [TEM]) give comparable results; and that strain (small difference in layer thicknesses) generally has a Gaussian distribution in the lognormal-type illites, but is often absent in the asymptotic-type illites.

  3. Influence of morphology on the emissive properties of dye-doped PVP nanofibers produced by electrospinning

    NASA Astrophysics Data System (ADS)

    Enculescu, Monica; Evanghelidis, Alex; Enculescu, Ionut

    2014-12-01

    Dye-doped polymer micro- and nanofibers with tailored light emission properties have great potential for applications in optical, optoelectronic, or photonic devices. In this study, these types of structures were obtained by electrospinning rhodamine 6 G-doped polyvinylpyrrolidone (PVP) using a polymer solution of 10% (mass) concentration in ethanol. Polymer nanofibers with different morphologies (smooth and beaded) and diameters of about 500 nm were obtained using different electrospinning conditions with the same solutions. Fluorescence optical microscopy observations showed that the dye was distributed uniformly in the doped PVP nanofibers. Different shifts were observed when we compared the wavelength of the dye emission band peak of the smooth nanofibers (566 nm) and the wavelength of the dye emission band peak of the beaded fibers (561.5 nm) produced by electrospinning in different conditions with the wavelength of the emission band peak for transparent thin films produced by spin coating (558 nm) using the same polymer solution. This demonstrates that it is possible to tune the optical properties of electrospun dye-doped polymer nanofibers simply by modifying the morphology of the material, i.e., the parameters of the electrospinning process.

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

    NASA Astrophysics Data System (ADS)

    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.

  5. Swelling, mechanical and friction properties of PVA/PVP hydrogels after swelling in osmotic pressure solution.

    PubMed

    Shi, Yan; Xiong, Dangsheng; Liu, Yuntong; Wang, Nan; Zhao, Xiaoduo

    2016-08-01

    The potential of polyvinyl alcohol/polyvinylpyrrolidone (PVA/PVP) hydrogels as articular cartilage replacements was in vitro evaluated by using a macromolecule-based solution to mimic the osmotic environment of cartilage tissue. The effects of osmotic pressure solution on the morphology, crystallinity, swelling, mechanical and friction properties of PVA/PVP hydrogels were investigated by swelling them in non-osmotic and osmotic pressure solutions. The results demonstrated that swelling ratio and equilibrium water content were greatly reduced by swelling in osmotic solution, and the swelling process was found to present pseudo-Fickian diffusion character. The crystallization degree of hydrogels after swelling in osmotic solution increased more significantly when it compared with that in non-osmotic solution. After swelling in osmotic solution for 28days, the compressive tangent modulus and storage modulus of hydrogels were significantly increased, and the low friction coefficient was reduced. However, after swelling in the non-osmotic solution, the compressive tangent modulus and friction coefficient of hydrogels were comparable with those of as-prepared hydrogels. The better material properties of hydrogels in vivo than in vitro evaluation demonstrated their potential application in cartilage replacement. PMID:27157740

  6. Electrical Properties of PVP-SiO2-TMSPM Hybrid Thin Films as OFET Gate Dielectric

    NASA Astrophysics Data System (ADS)

    Bahari, A.; Shahbazi, M.

    2016-02-01

    Organic-inorganic polyvinylpyrrolidone-silicon dioxide-3-(trimethoxysilyl)propyl methacrylate (PVP-SiO2-TMSPM) hybrid solutions have been synthesized using the sol-gel process with different amounts of TMSPM as coupling agent and equivalent amounts of PVP and SiO2. Hybrid solutions were deposited on p-type Si(111) substrates using the spin coating technique, as a gate dielectric material for use in thin-film transistors. The structural properties of the samples were investigated using Fourier-transform infrared spectroscopy and x-ray diffraction analysis. Atomic force microscopy and scanning electron microscopy techniques were applied to study the topography and morphology of the hybrid thin-film samples. Current-voltage ( I- V) curves, capacitance-voltage ( C- V) measurements, and the electrical properties of the organic hybrid thin-film gate dielectrics were also studied in a metal-insulator/polymer-semiconductor structure. According to the results, the J GS curves in terms of V GS showed gate leakage current densities small enough for use as gate dielectric material at interface layers. At V DS = 30 V, in the saturation region, I DS curves in terms of V GS presented higher charge carrier mobility ( μ FET,S = 0.0584 cm2 s-1 V-1) due to lower dielectric constant ( k = 11.43) in the sample with 0.05 weight ratio of TMSPM compared with other samples with different weight ratios of TMSPM.

  7. Optical, electrical, thermal properties of cadmium chloride doped PVA - PVP blend

    NASA Astrophysics Data System (ADS)

    Baraker, Basavarajeshwari M.; Hammannavar, Preeti B.; Lobo, Blaise

    2015-06-01

    Films of polyvinylalcohol (PVA) - polyvinylpyrrolidone (PVP) blend doped with Cadmium Chloride (CdCl2) 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 (CdCl2). 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%.

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

    SciTech Connect

    Baraker, Basavarajeshwari M.; Hammannavar, Preeti B.; Lobo, Blaise

    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%.

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

    NASA Astrophysics Data System (ADS)

    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.

  10. Evaluation of PVP/Au Nanocomposite Fibers as Heterogeneous Catalysts in Indole Synthesis.

    PubMed

    Savva, Ioanna; Kalogirou, Andreas S; Achilleos, Mariliz; Vasile, Eugenia; Koutentis, Panayiotis A; Krasia-Christoforou, Theodora

    2016-01-01

    Electrospun nanocomposite fibers consisting of crosslinked polyvinylpyrrolidone (PVP) chains and gold nanoparticles (Au NPs) were fabricated, starting from highly stable PVP/Au NP colloidal solutions with different NP loadings, followed by thermal treatment. Information on the morphological characteristics of the fibers and of the embedded Au NPs was obtained by electron microscopy. Cylindrical, bead-free fibers were visualized by Scanning Electron Microscopy (SEM) while Transmission Electron Microscopy (TEM) and Energy Diffraction X-ray (EDX) analysis supported the presence of Au NPs within the fibers and gave information on their morphologies and average diameters. These materials were briefly evaluated as heterogeneous catalytic supports for the gold-catalyzed intramolecular cyclisation of 2‑(phenylethynyl)aniline to form 2-phenyl-1H-indole. The performance of the gold catalyst was strongly dependent on the Au NP size, with the system containing the smallest Au NPs being the more effective. Moreover, a slight drop of their catalytic efficiency was observed after three consecutive reaction runs, which was attributed to morphological changes as a consequence of fiber merging. PMID:27626399

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

    NASA Astrophysics Data System (ADS)

    Abd El-Rehim, H. A.; Hegazy, E. A.; Khalil, F. H.; Hamed, N. A.

    2007-01-01

    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 p Ka of PAAc. The prepared inter-polymer complex could be used for application as drug carriers.

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

    NASA Astrophysics Data System (ADS)

    Vahdatkhah, Parisa; Madaah Hosseini, Hamid Reza; Khodaei, Azin; Montazerabadi, Ali Reza; Irajirad, Rasoul; Oghabian, Mohamad Ali; Delavari H., Hamid

    2015-05-01

    Synthesis of polyvinyl pyrrolidone (PVP) coated ultrasmall Gd2O3 nanoparticles (NPs) with enhanced T1-weighted signal intensity and r2/r1 ratio close to unity is performed by a microwave-assisted polyol process. PVP coated Gd2O3NPs 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 (r1) and transversal relaxation (r2) of Gd2O3NPs is measured by a 3 T MRI scanner. The results showed considerable increasing of relaxivity for Gd2O3NPs in comparison to gadolinium chelates which are commonly used for clinical magnetic resonance imaging. In addition, a mechanism for Gd2O3NPs formation and in situ surface modification of PVP-grafted Gd2O3NPs is proposed.

  13. The role of the prostatic median lobe in urinary symptoms following photoselective vaporization of the prostate (PVP)

    NASA Astrophysics Data System (ADS)

    Berry, Tristan T.; Nseyo, Unyime O.

    2004-07-01

    Introduction and Objective: Photoselective vaporization of the prostate (PVP) remains a relatively new addition to our armamentarium of minimally invasive surgical treatments for symptomatic benign prostatic hypertrophy/enlargement. Early favorable reports of the safety and efficacy of PVP do not alleviate the need to investigate factors that may further improve the safety margin and efficacy outcomes of PVP in the management of symptomatic benign prostatic enlargement (BPE). Consequently, we investigated the role of enlarged or prominent intravesical median/middle lobe of the prostate in mediating urinary symptoms following PVP. Materials and Methods: Forty-one non-consecutive patients diagnosed with BPE were enrolled under an Institutional Review Board approved multi-center protocol at the Hunter McGuire Veterans Administration Medical Center, Richmond, Virginia, for PVP treatment using the 80W quasi-continuous wave KTP laser. Perioperative and postoperative complications/adverse events were assessed. Urodynamic parameters: AUA-SI, QOL, Qmax and PVR; and PSA were assessed at baseline, 1, 3, 6 and 12 months postoperatively. Results: The forty-one patients were sub-stratified based on cystoscopic evidence of prominent median/middle lobe (n=17)(Study Group), and absence of median lobe (n = 24). Seven of seventeen (41.1%) patients with and 10/24 (41.7%) patients without median lobes experienced adverse urinary symptoms, which resolved within 7-8 months. All 41 patients have demonstrated significant improvements in urodynamic, that is, flow rates, post void residual volumes and clinical (QOL) outcome measures. Conclusion: Niagara Green Light PVP procedure did not result in heightened severity of voiding symptoms in those BPE patients with prominent intravesical median lobes.

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

    PubMed

    Rask, Malte Bille; Knopp, Matthias Manne; Olesen, Niels Erik; Holm, René; Rades, Thomas

    2016-03-31

    In this study, the influence of copolymer composition on drug-polymer solubility was investigated. The solubility of the model drug celecoxib (CCX) in various polyvinylpyrrolidone/vinyl acetate (PVP/VA) copolymer compositions (70/30, 60/40, 50/50 and 30/70 w/w) and the pure homopolymers polyvinylpyrrolidone (PVP) and polyvinyl acetate (PVA) was predicted at 25 °C using a thermal analysis method based on the recrystallization of a supersaturated amorphous dispersion (recrystallization method). These solubilities were compared with a prediction based on the solubility of CCX in the liquid monomeric precursors of PVP/VA, N-vinylpyrrolidone (NVP) and vinyl acetate (VA), using the Flory-Huggins lattice theory (liquid monomer solubility approach). The solubilities predicted from the liquid monomer solubility approach increased linearly with increasing VP/VA ratio from 0.03-0.60 w/w. Even though the solubilities predicted from the recrystallization method also increased with increasing VP/VA ratio from 0.02-0.40 w/w, the predicted solubility seemed to approach a plateau at high VP/VA ratios. Increasing positive deviations from the Gordon-Taylor equation with increasing VP/VA ratio indicated strong interactions between CCX and the VP repeat unit, which was in accordance with the relatively high solubilities predicted using both methods. As the solubility plateau may be a consequence of steric hindrance caused by the size differences between CCX and the VP repeat units, it is likely that a CCX molecule 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 dispersion without compromising the drug-polymer solubility. This knowledge could be used advantageously in future development of amorphous drug delivery systems as

  15. Effect of strain on viscoelastic behavior of fresh, swelled and mineralized PVP-CMC hydrogel

    NASA Astrophysics Data System (ADS)

    Saha, Nabanita; Vyroubal, Radek; Shah, Rushita; Kitano, Takeshi; Saha, Petr

    2013-04-01

    Mineralization of calcium carbonate (CaCO3) in hydrogel matrix is one of the most interesting topics of research by material scientists for the development of bio-inspired polymeric biomaterial for biomedical applications especially for bone tissue regeneration. As per our knowledge there was no work reported about rheological properties of CaCO3 mineralized hydrogel though some works have done on mineralization of CaCO3 in various gel membranes, and also it was reported about the viscoelastic properties of Agarose, Cellulose, PVA and PVPCMC hydrogels. This paper mainly focuses about the effect of strain on viscoelastic properties of fresh, swelled and mineralized (CaCO3) PVP-CMC hydrogel. All these three types of hydrogel sustain (or keep) strictly the elastic properties when low strain (1%) is applied, but at higher strain (10%) the viscoelastic moduli (G' and G") show significant change, and the nature of these materials turned from elastic to viscous.

  16. Synthesis of PVA/PVP hydrogels having two-layer by radiation and their physical properties

    NASA Astrophysics Data System (ADS)

    Park, Kyoung Ran; Nho, Young Chang

    2003-06-01

    In these studies, two-layer hydrogels which consisted of polyurethane membrane and a mixture of polyvinyl alcohol(PVA)/poly- N-vinylpyrrolidone(PVP)/glycerin/chitosan were made for the wound dressing. Polyurethane was dissolved in solvent, the polyurethane solution was poured on the mould, and then dried to make the thin membrane. Hydrophilic polymer solutions were poured on the polyurethane membranes, they were exposed to gamma irradiation or two steps of 'freezing and thawing' and gamma irradiation doses to make the hydrogels. The physical properties such as gelation, water absorptivity, and gel strength were examined to evaluate the hydrogels for wound dressing. The physical properties of hydrogels such as gelation and gel strength was greatly improved when polyurethane membrane was used as a covering layer of hydrogel, and the evaporation speed of water in hydrogel was reduced.

  17. PVP- coated naringenin nanoparticles for biomedical applications - In vivo toxicological evaluations.

    PubMed

    Kumar, R Pradeep; Abraham, Annie

    2016-09-25

    Naringenin (NAR) is one of the naturally occurring flavonoids found in citrus fruits and exerts a wide variety of pharmacological activities. The clinical relevance of naringenin is limited by its low solubility and minimal bioavailability, owing to its largely hydrophobic ring structure. The aim of the present study is to develop a novel naringenin nanoparticle system (NAR NP) using simple nanoprecipitation technique with polyvinylpyrrolidone (PVP) as the hydrophilic carrier. The synthesized nanoparticles were characterized using XRD, FTIR, SEM and EDX. The characterization study revealed the nanoscale properties and the interactions between NAR and PVP. In vivo toxicological evaluations were carried out at various doses (1, 5, 10 & 50 mg/kg body wt) in male Sprague-Dawley rats in comparison with silver nanoparticle (AgNP) at toxic concentration (50 mg/kg body wt). The altered hepatotoxicity markers, hematology parameters and antioxidant defense system were observed in AgNP- treated rats. But NAR NP - treated rats did not show any biochemical alterations and improved the antioxidant defense indices when compared to control group, by virtue of the pharmacological properties exerted by NAR. The modulatory effect of NAR NP over inflammatory and stress signaling cascades were confirmed by the normalized mRNA expressions of NF-κB, TNF-α and IL-6. The histopathological analysis of liver, kidney and heart reinforce our findings. These studies provide preliminary answers to some of the key biological issues raised over the use and safety of nanoparticles for diagnostic and therapeutic applications. Consequently, we suggest that the safe NAR NP can be used to reduce the dosage of NAR, improve its bioavailability and merits further investigation for therapeutic applications. PMID:27417253

  18. Water-soluble and biocompatible MnO@PVP nanoparticles for MR imaging in vitro and in vivo.

    PubMed

    Hu, Xiaoqing; Ji, Yuxuan; Wang, Mingliang; Miao, Fei; Ma, Hongmei; Shen, Hebai; Jia, Nengqin

    2013-06-01

    The uniform-sized manganese oxide nanoparticles (the oleic-capped MnO NPs) were synthesized by the thermal decomposition of Mn-oleate complex and were transferred into water with the help of cationic surfactant of cetyltrimethyl ammonium bromide (CTAB), then the poly(vinylpyrrolidone) (PVP) membrane was further coated on to them with the aid of anionic dispersant of poly(styrenesulfonate) (PSS) by layer-by-layer electrostatic assembly to render them water soluble and biocompatible. They were characterized by transmission electron microscopy (TEM), dynamic light scattering (DLS), X-ray diffraction (XRD), Fourier-transform infrared (FTIR) and MTT assay. In vitro cellular uptake test revealed the MnO@PVP NPs were low cytotoxic, biocompatible and could be used as a T,-positive contrast agent for passive targeting magnetic resonance imaging (MRI). Interestingly, signal enhancement in cerebral spinal fluid (CSF) spaces in vivo experiment suggested that the MnO@PVP NPs can pass through the blood brain barrier (BBB). These results show that MnO@PVP NPs are good candidates as MRI contrast agents with the lack of cytotoxicity and have great potential applications in magnetic nano-device and biomagnetic field. PMID:23858961

  19. Molecular Variability of the Adhesin-Encoding Gene pvpA among Mycoplasma gallisepticum Strains and Its Application in Diagnosis

    PubMed Central

    Liu, T.; García, M.; Levisohn, S.; Yogev, D.; Kleven, S. H.

    2001-01-01

    Mycoplasma gallisepticum is an important pathogen of chickens and turkeys that causes considerable economic losses to the poultry industry worldwide. The reemergence of M. gallisepticum outbreaks among poultry, the increased use of live M. gallisepticum vaccines, and the detection of M. gallisepticum in game and free-flying song birds has strengthened the need for molecular diagnostic and strain differentiation tests. Molecular techniques, including restriction fragment length polymorphism of genomic DNA (RFLP) and PCR-based random amplification of polymorphic DNA (RAPD), have already been utilized as powerful tools to detect intraspecies variation. However, certain intrinsic drawbacks constrain the application of these methods. The main goal of this study was to determine the feasibility of using an M. gallisepticum-specific gene encoding a phase-variable putative adhesin protein (PvpA) as the target for molecular typing. This was accomplished using a pvpA PCR-RFLP assay. Size variations among PCR products and nucleotide divergence of the C-terminus-encoding region of the pvpA gene were the basis for strain differentiation. This method can be used for rapid differentiation of vaccine strains from field isolates by amplification directly from clinical samples without the need for isolation by culture. Moreover, molecular epidemiology of M. gallisepticum outbreaks can be performed using RFLP and/or sequence analysis of the pvpA gene. PMID:11326008

  20. Physicochemical characterization and in vitro dissolution studies of solid dispersions of ketoprofen with PVP K30 and d-mannitol.

    PubMed

    Yadav, Pankajkumar S; Kumar, Vikas; Singh, Udaya Pratap; Bhat, Hans Raj; Mazumder, B

    2013-01-01

    Aim of the present study was to improve the solubility and dissolution rate of poorly water soluble, BCS class-II drug Ketoprofen (KETO) by solid-dispersion approach. Solid dispersions were prepared by using polyvinylpyrrolidone K30 (PVP K30) and d-mannitol in different drugs to carrier ratios. Dispersions with PVP K30 were prepared by kneading and solvent evaporation techniques, whereas solid dispersions containing d-mannitol were prepared by kneading and melting techniques. These formulations were characterized in the liquid state by phase-solubility studies and in the solid state by Differential Scanning Calorimetry (DSC), Fourier Transform Infrared (FTIR) spectroscopy, X-ray diffraction (XRD) and Scanning Electron Microscopy (SEM). The aqueous solubility of KETO was favored by the presence of both carriers. The negative values of Gibbs free energy illustrate the spontaneous transfer from pure water to the aqueous polymer environment. Solid state characterization indicated KETO was present as fine particles in d-mannitol solid dispersions and entrapped in carrier matrix of PVP K30 solid dispersions. In contrast to the very slow dissolution rate of pure KETO, dispersions of drug in carriers considerably improved the dissolution rate. This can be attributed to increased wettability and dispersibility, as well as decreased crystallinity and increase in amorphous fraction of drug. Solid dispersions prepared with PVP K30 showed the highest improvement in dissolution rate of KETO. Even physical mixtures of KETO prepared with both carriers also showed better dissolution profiles than those of pure KETO. PMID:24109206

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

    SciTech Connect

    Xue, Yannan; Ren, Xiaolei; Zhai, Xuefeng; Yu, Min

    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.

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

    PubMed

    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

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

    NASA Astrophysics Data System (ADS)

    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

  4. Preparation and characterization of PVP-PVA-ZnO blend polymer nano composite films

    NASA Astrophysics Data System (ADS)

    Divya, S.; Saipriya, G.; Hemalatha, J.

    2016-05-01

    Flexible self-standing films of PVP-PVA blend composites are prepared by using ZnO as a nano filler at different concentrations. The structural, compositional, morphological and optical studies made with the help of X-ray diffraction (XRD), Fourier Transform Infra-Red spectroscopy (FTIR), Scanning electron microscope (SEM), Atomic Force Microscopy (AFM), Ultraviolet-visible spectroscopy (UV-vis) and Photoluminescence (PL) spectra are presented in this paper. The results of XRD indicate that ZnO nanoparticles are formed with hexagonal phase in the polymeric matrix. SEM images show the dispersion of ZnO nano filler in the polymer matrix. UV-vis spectra reveal that the absorption peak is centered around 235nm and 370nm for the nano composite films. The blue shift is observed with decrease in the concentration of the nano filler. PL spectra shows the excitation wavelength is given at 320nm.The emission peaks were observed at 383 nm ascribing to the electronic transitions between valence band and conduction band and the peak at 430 nm.

  5. Application of Carbopol/PVP interpolymer complex to prepare mucoadhesive floating granule.

    PubMed

    Chun, Myung-Kwan; Bhusal, Prabhat; Choi, Hoo-Kyun

    2013-06-01

    Novel mucoadhesive floating granule was prepared using Carbopol/PVP interpolymer complex to deliver hydrophilic drugs in a controlled manner. Acetaminophen was used as a model drug. Maximum floatability of the granules was obtained at the ratio of 1/1, where 95 % of the granules floated for 12 h. As the concentration of sodium bicarbonate increased, both the floating duration and the release rate of the drug increased. The granules without sodium bicarbonate floated only for 2 h and floating onset time was 15 min. The release rate of drug gradually increased as the drug content in the granule increased. As the drug content in the granules increased, duration of adhesion decreased. However, the decrease in adhesion duration was minimal up to 40 % of drug content. The release rate from the granules prepared by dry granulation method was faster than that by wet granulation. The granules prepared by dry granulation method led to formation of highly porous structure; whereas, that by wet granulation method showed non-porous structure. The optimum size of the granules to retard the release of the model drug was within the range of 3-4 mm. Based on both mucoadhesive and buoyant properties, the floating granules are expected to reside in the upper part of the stomach for sufficient period of time and release the drug in a sustained manner. PMID:23435911

  6. Synthesis and Raman analysis of SnS nanoparticles synthesized by PVP assisted polyol method

    SciTech Connect

    Baby, Benjamin Hudson; Mohan, D. Bharathi

    2015-06-24

    SnS film was prepared by a simple drop casting method after synthesizing SnS nanoparticles by using PVP assisted polyol method. Confocal Raman study was carried out for the as deposited and annealed (150, 300 and 400 °C) films at two different excitation wavelengths 514 and 785 nm. At the excitation wavelength of 514 nm, the Raman modes showed for a mixed phase of SnS and SnS{sub 2} up to 150 °C and then only a pure SnS phase was observed up to 400 °C due to the dissociation of SnS{sub 2} in to SnS by releasing S. The increase in intensity of Raman (A{sub g} and B{sub 3g}) as well as IR (B{sub 3u}) active modes of SnS are observed with increasing annealing temperature at excitation wavelength 785 nm due to the increased crystallinity and inactiveness of SnS{sub 2} modes. X-ray diffraction confirming the formation of a single phase of SnS while the greater homogeneity in both size and shape of SnS nanoparticles were confirmed through surface morphology from SEM.

  7. Synthesis and Raman analysis of SnS nanoparticles synthesized by PVP assisted polyol method

    NASA Astrophysics Data System (ADS)

    Baby, Benjamin Hudson; Mohan, D. Bharathi

    2015-06-01

    SnS film was prepared by a simple drop casting method after synthesizing SnS nanoparticles by using PVP assisted polyol method. Confocal Raman study was carried out for the as deposited and annealed (150, 300 and 400 °C) films at two different excitation wavelengths 514 and 785 nm. At the excitation wavelength of 514 nm, the Raman modes showed for a mixed phase of SnS and SnS2 up to 150 °C and then only a pure SnS phase was observed up to 400 °C due to the dissociation of SnS2 in to SnS by releasing S. The increase in intensity of Raman (Ag and B3g) as well as IR (B3u) active modes of SnS are observed with increasing annealing temperature at excitation wavelength 785 nm due to the increased crystallinity and inactiveness of SnS2 modes. X-ray diffraction confirming the formation of a single phase of SnS while the greater homogeneity in both size and shape of SnS nanoparticles were confirmed through surface morphology from SEM.

  8. Physiochemical Characterization and Release Rate Studies of SolidDispersions of Ketoconazole with Pluronic F127 and PVP K-30

    PubMed Central

    Kumar, Pankaj; Mohan, Chander; KanamSrinivasan Uma Shankar, Mara; Gulati, Monica

    2011-01-01

    In the present study solid dispersions of the antifungal drug Ketoconazole were prepared with Pluronic F-127 and PVP K-30 with an intention to improve its dissolution properties. Investigations of the properties of the dispersions were performed using release studies, Differential scanning calorimetery (DSC), X-ray powder diffraction (XRD) and Fourier transform infrared (FTIR). The results obtained showed that the rate of dissolution of Ketoconazole was considerably improved when formulated in solid dispersions with PVP K-30 and Pluronic F-127 as compared with pure drug and physical mixtures. The results from DSC and XRD studies showed the transition of crystalline nature of drug to amorphous form, while FTIR studies demonstrated the absence of drug-carriers interaction. PMID:24250403

  9. Study on micro structural and electrical properties of FeCl3 doped HPMC/PVP polymer blend films

    NASA Astrophysics Data System (ADS)

    Somashekarappa, H.; Prakash, Y.; Urs, R. Gopal Krishne; Somashekar, R.

    2015-06-01

    Solid polymer electrolyte (SPE) based on Hydroxypropylemethylcellulose (HPMC) and Polyvinylpyrrolidone (PVP) polymer blend films complexed with different weight ratio of FeCl3 were prepared using solution casting method and investigated using X-ray line profile analysis. Here an attempt has been made to study the changes in crystal imperfection parameters in HPMC/PVP blend films with the increase in concentration of FeCl3. The obtained results shows that decrease in micro crystalline parameters results in increase in the amorphous nature of the film yields more flexibility, biodegradability and good ionic conductivity. AC conductivity measurements in these films show that the conductivity increases as the concentration of FeCl3 increases. These films were suitable for electro chemical applications.

  10. Quantitative PVP mapping in PVDF hollow fiber membranes by using Raman spectroscopy coupled with spectral chemiometrics analysis

    NASA Astrophysics Data System (ADS)

    Dufour, E.; Gassara, S.; Petit, E.; Pochat-Bohatier, C.; Deratani, A.

    2015-07-01

    Fabrication of fouling resistant UF membranes requires the use of hydrophilic polymer additives that must be trapped in the polymer matrix during the phase separation processing. The knowledge of the polymeric additive distribution across the whole thickness should help to the design of more efficient membranes. This paper aims at developing a new methodology based on Raman microscopy spectroscopy owing to its high spatial resolution. A UF hollow fiber made from a blend of PVDF as polymer matrix and PVP as additive was chosen as a model membrane for this study. The PVP concentration profile along the cross-section radial axis was determined by using two ways of spectrum treatment including the analytical method by the peak intensity ratio calculation and a multivariate analysis with a partial least-squares regression model. The feasibility of the two approaches was discussed.

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

    NASA Astrophysics Data System (ADS)

    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.

  12. A novel biocompatible conducting polyvinyl alcohol (PVA)-polyvinylpyrrolidone (PVP)-hydroxyapatite (HAP) composite scaffolds for probable biological application.

    PubMed

    Chaudhuri, B; Mondal, B; Ray, S K; Sarkar, S C

    2016-07-01

    We have prepared biocompatible composites of 80wt% polyvinyl alcohol (PVA)-(20wt%) polyvinylpyrrolidone (PVP) blend with different concentrations of bioactive nanohydroxyapatite, Ca10(PO4)6(HO)2 (HAP). The composite films demonstrated maximum effective conductivity (σ∼1.64×10(-4)S/m) and effective dielectric constant (ε∼290) at percolation threshold concentration (∼10wt% HAP) at room temperature. These values of σ and ε are much higher than those of PVA, PVP or HAP. Our preliminary observation indicated excellent biocompatibility of the electrospun fibrous meshes of two of these composites with different HAP contents (8.5 and 5wt% within percolation threshold concentration) using NIH 3T3 fibroblast cell line. Cells viability on the well characterized composite fibrous scaffolds was determined by MTT [3-(4,5-di-methylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] assay analysis. Enhancement of σ, due to HAP addition, was found to show increased biocompatibility of the fibrous scaffold. Enhanced σ value of the PVA/PVP-HAP composite provided supporting cues for the increased cell viability and biocompatibility of the composite fibrous meshes. Excellent biocompatibility these electrospun composite scaffolds made them to plausible potential candidates for tissue engineering or other biomedical applications. PMID:26998868

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

    NASA Astrophysics Data System (ADS)

    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.

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

    PubMed

    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. PMID:26899127

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

    NASA Astrophysics Data System (ADS)

    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.

  16. Fast releasing oral electrospun PVP/CD nanofiber mats of taste-masked meloxicam.

    PubMed

    Samprasit, Wipada; Akkaramongkolporn, Prasert; Ngawhirunpat, Tanasait; Rojanarata, Theerasak; Kaomongkolgit, Ruchadaporn; Opanasopit, Praneet

    2015-06-20

    Fast release and taste masking of meloxicam (MX)-loaded polyvinylpyrrolidone (PVP)/cyclodextrin (CD) nanofiber mats were developed using an electrospinning process. CDs were blended to improve the stability of the mats. The morphology and diameter of the mats were determined using scanning electron microscopy (SEM); physical and mechanical properties were also studied. The MX content, disintegration time, MX release and cytotoxicity of the mats were investigated. In vivo studies were also performed in healthy human volunteers. The results indicated that the mats were successfully prepared with fiber in the nanometer range. MX was well incorporated into the mats, with an amorphous form. The mats showed suitable tensile strength. CDs improved the physical stability by their cage-like supramolecular structure to protect from humidity and moisture, and create bead free nanofiber mats. The nanofiber mats with CDs were physically stable without any hygroscopicity and fusion. A fast disintegration and release of MX was achieved. Moreover, this mat released MX faster than the MX powder and commercial tablets. The cytotoxicity test revealed that mats were safe for a 5-min incubation. The disintegration studies indicated that in vivo disintegration agreed with the in vitro studies; the mat rapidly disintegrated in the mouth. The less bitter of MX was occurred in the mats that incorporated CD, menthol and aspartame. In addition, this mat was physical stable for 6 months. The results suggest that these mats may be a good candidate for fast dissolving drug delivery systems of bitter drugs to increase the palatability of dosage forms. PMID:25899284

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

    NASA Astrophysics Data System (ADS)

    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.

  18. PVP-Assisted Solvothermal Synthesis of High-Yielded Bi2Te3 Hexagonal Nanoplates: Application in Passively Q-Switched Fiber Laser

    NASA Astrophysics Data System (ADS)

    He, Xin; Zhang, Hang; Lin, Wei; Wei, Rongfei; Qiu, Jianrong; Zhang, Mei; Hu, Bin

    2015-10-01

    High-yielded Bi2Te3 hexagonal nanoplates were fabricated via a facile solvothermal method with the assistance of poly (vinyl pyrrolidone) (PVP). Effects of PVP molecular weight and concentration on the morphology and size distribution of the products were illustrated in this study. Molecular weight of PVP is significant for determining the morphology of Bi2Te3. The hexagonal nanoplates with high yield were obtained in the presence of PVP with molecular weight of 40000-45000. The average size and size distribution of Bi2Te3 nanoplates can be slightly varied by controlling concentration of PVP. High-yielded Bi2Te3 nanoplates exhibit characteristics of saturable absorption, identified by open-aperture Z-scan technique. The synthesized Bi2Te3 nanoplates with large saturation intensity of 4.6 GW/cm2 and high modulation depth of 45.95% generated a stable passively Q-switched fiber laser pulse at 1.5 μm. In comparison with recently reported Q-switched fiber lasers utilizing exfoliated Bi2Te3 nanosheets, our passive Q-switching operations could be conducted at a relatively low threshold power of 30.2 mW or a quite high output power of 99.45 mW by tuning the cavity parameters.

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

    NASA Astrophysics Data System (ADS)

    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.

  20. PVP-Assisted Solvothermal Synthesis of High-Yielded Bi2Te3 Hexagonal Nanoplates: Application in Passively Q-Switched Fiber Laser.

    PubMed

    He, Xin; Zhang, Hang; Lin, Wei; Wei, Rongfei; Qiu, Jianrong; Zhang, Mei; Hu, Bin

    2015-01-01

    High-yielded Bi2Te3 hexagonal nanoplates were fabricated via a facile solvothermal method with the assistance of poly (vinyl pyrrolidone) (PVP). Effects of PVP molecular weight and concentration on the morphology and size distribution of the products were illustrated in this study. Molecular weight of PVP is significant for determining the morphology of Bi2Te3. The hexagonal nanoplates with high yield were obtained in the presence of PVP with molecular weight of 40000-45000. The average size and size distribution of Bi2Te3 nanoplates can be slightly varied by controlling concentration of PVP. High-yielded Bi2Te3 nanoplates exhibit characteristics of saturable absorption, identified by open-aperture Z-scan technique. The synthesized Bi2Te3 nanoplates with large saturation intensity of 4.6 GW/cm(2) and high modulation depth of 45.95% generated a stable passively Q-switched fiber laser pulse at 1.5 μm. In comparison with recently reported Q-switched fiber lasers utilizing exfoliated Bi2Te3 nanosheets, our passive Q-switching operations could be conducted at a relatively low threshold power of 30.2 mW or a quite high output power of 99.45 mW by tuning the cavity parameters. PMID:26511763

  1. PVP-Assisted Solvothermal Synthesis of High-Yielded Bi2Te3 Hexagonal Nanoplates: Application in Passively Q-Switched Fiber Laser

    PubMed Central

    He, Xin; Zhang, Hang; Lin, Wei; Wei, Rongfei; Qiu, Jianrong; Zhang, Mei; Hu, Bin

    2015-01-01

    High-yielded Bi2Te3 hexagonal nanoplates were fabricated via a facile solvothermal method with the assistance of poly (vinyl pyrrolidone) (PVP). Effects of PVP molecular weight and concentration on the morphology and size distribution of the products were illustrated in this study. Molecular weight of PVP is significant for determining the morphology of Bi2Te3. The hexagonal nanoplates with high yield were obtained in the presence of PVP with molecular weight of 40000–45000. The average size and size distribution of Bi2Te3 nanoplates can be slightly varied by controlling concentration of PVP. High-yielded Bi2Te3 nanoplates exhibit characteristics of saturable absorption, identified by open-aperture Z-scan technique. The synthesized Bi2Te3 nanoplates with large saturation intensity of 4.6 GW/cm2 and high modulation depth of 45.95% generated a stable passively Q-switched fiber laser pulse at 1.5 μm. In comparison with recently reported Q-switched fiber lasers utilizing exfoliated Bi2Te3 nanosheets, our passive Q-switching operations could be conducted at a relatively low threshold power of 30.2 mW or a quite high output power of 99.45 mW by tuning the cavity parameters. PMID:26511763

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

    NASA Astrophysics Data System (ADS)

    Dyartanti, Endah R.; Purwanto, Agus; Widiasa, I. Nyoman; Susanto, Heru

    2016-02-01

    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 (LiPF6) 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.

  3. Polyvinylphenol (PVP) microcapacitors printed by laser-induced forward transfer (LIFT): multilayered pixel design and thermal analysis investigations

    NASA Astrophysics Data System (ADS)

    Constantinescu, C.; Rapp, L.; Rotaru, P.; Delaporte, P.; Alloncle, A. P.

    2016-04-01

    Highlights • Laser-induced transfer is used for the printing of multilayered microcapacitors • The dielectric film is made of PVP, and the electrodes are made of Ag • Thermal behaviour of the polymer is discussed with respect to the laser processing • The structure and electrical properties of the capacitors are discussed Ag/polyvinylphenol (PVP) multilayered pixels are printed by laser-induced forward transfer (LIFT) technique for thin film microcapacitor applications. The third harmonic (3ω/355 nm, τ  =  50 ps) of a solid state neodymium-doped yttrium aluminium garnet (Nd:YAG) laser source is employed throughout our LIFT experiments. By selecting adequate printing parameters (e.g. donor thickness, laser fluence, background pressure), we show how functional microcapacitors are fabricated. At ~350 μm in lateral size and 300 nm thickness of the dielectric film, the pixels have capacities in the picofarad range. We discuss the laser influence during the pixel transfer process and highlight the polymer’s thermal behaviour.

  4. Physicochemical evaluation of PVP-thiazide diuretic interactions in co-spray-dried composites--analysis of glass transition composition relationships.

    PubMed

    Tajber, Lidia; Corrigan, Owen I; Healy, Anne Marie

    2005-04-01

    The aim of this study was to evaluate the possible interactions in the solid state between the thiazide diuretics: bendroflumethiazide (BFMT), hydroflumethiazide (HFMT) and hydrochlorothiazide (HCT) and polyvinylpyrrolidone (PVP) following processing. The glass transition temperatures (T(g)s) of a range of binary co-spray-dried PVP-thiazide composites were determined and compared to the predictions of the Gordon-Taylor, Fox, Couchman-Karasz, Kwei and Schneider equations. The solid composites of the thiazide diuretics and PVP were prepared by a spray drying technique. Properties of composites were determined with the use of helium pycnometry and FTIR spectroscopy. For many systems studied the experimentally detected T(g)s exhibited large positive deviations when compared with the values predicted by the Gordon-Taylor, Fox and Couchman-Karasz equations. The data was better fitted by the Schneider equation consistent with a drug-polymer interaction. FTIR analysis revealed that strong hydrogen bonding between the sulphonamide groups of the thiazide diuretics and the PVP molecule was responsible for the increase in the T(g)s. Additionally, in the case of BFMT-PVP composites, an interaction between the phenyl group and polymer ring was apparent. Glass transition-composition behaviour for amorphous drug-PVP composites deviated from the predictions of the commonly used Gordon-Taylor equation. Deviations were consistent with interactions between the components in the amorphous mixtures. The Schneider equation may be successfully applied to fit the Tg-composition profiles obtained, where other models fail to give good predictions. PMID:15784345

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

    PubMed Central

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

    2016-01-01

    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. PMID:27143126

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

    PubMed

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

    2016-01-01

    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. PMID:27143126

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

    PubMed Central

    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

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

    NASA Astrophysics Data System (ADS)

    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.

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

    SciTech Connect

    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. Effect of Polyvnylpyrrolidone (PVP) in Binary Solution on the Performance of Polyethersulfone Hollow Fibre Membrane for Sodium Chloride Separation

    NASA Astrophysics Data System (ADS)

    Bolong, N.; Ismail, A. F.; Salim, M. R.

    2010-03-01

    In membrane preparation, phase inversion is a versatile technique that allow polymer to be transformed from liquid to a solid state in a controlled manner. The preparation and process involves many factors and parameters specifically in fabricating hollow fibre membrane. In this study, dope solution factor in the process of fabricating hollow fibre membrane were explored. The effects of polymer concentration and polyvinylpyrrolidone (PVP) as additive in the dope solution on the morphology and separation performance were found able to produced high porous membranes, well interconnected pores and surface properties. Employing polyethersulfone (PES) as polymer, hollow fibre membranes were fabricated using N-methyl-2-pyrrolidone (NMP) as solvent and using water as the external coagulant. Finally the fabricated ultrafiltration membranes were characterized and evaluated based on solute transport concentration (sodium chloride) and pure water permeation properties.

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

    NASA Astrophysics Data System (ADS)

    Venugopal, Krishnaveni; Murugappan, Minnoli; Dharmalingam, Sangeetha

    2015-10-01

    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.

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

    PubMed

    Knopp, Matthias Manne; Nguyen, Julia Hoang; Mu, Huiling; Langguth, Peter; Rades, Thomas; Holm, René

    2016-03-01

    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 supersaturation whereas the hydrophobic monomer vinyl acetate (VA) was responsible for the stabilization of the supersaturated solution. For CCX, there was an optimal copolymer composition around 50-60% VP content where further replacement of VP monomers with VA monomers did not have any biopharmaceutical advantages. A linear relationship was found between the in vitro AUC(0-4h) and in vivo AUC(0-24h) for the CCX:PVP/VA systems, indicating that the non-sink in vitro dissolution method applied in this study was useful in predicting the in vivo performance. These results indicated that when formulating a poorly 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 to the required in vivo plasma-concentration profile. As this ratio is likely to be drug dependent, determining the optimal ratio between the hydrophilic (dissolution enhancing) and hydrophobic (crystallization inhibiting) monomers for a given drug is imperative. PMID:26769250

  13. The in vitro effective antiviral action of povidone-iodine (PVP-I) may also have therapeutic potential by its intravenous administration diluted with Ringer's solution.

    PubMed

    Sabracos, Labros; Romanou, Solomi; Dontas, Ismene; Coulocheri, Stavroula; Ploumidou, Kathrin; Perrea, Despina

    2007-01-01

    The use of povidone-iodine (PVP-I) is well known in clinical medical practice. In vitro studies of cell cultures infected by HIV and H5N1 virus have shown that PVP-I has an antiviral action, while the cell hosts were not affected and survived. It is therefore worth investigating whether PVP-I, diluted with Ringer's solution, may have a therapeutic effect by parenteral administration. Specifically, the question is whether small concentrations of intravenous PVP-I could be well tolerated by the human organism, and in addition, if it would be possible to detect a beneficial activity. Its intravenous use may have a potential value against infections (by microbes, viruses, fungi and parasites), as well as an anti-inflammatory activity, especially in cases where antibiotics are ineffective. It could be used as a blood disinfectant, for treating burns, for the prevention of cancer, for the therapy of H5N1 influenza after its mutation, and other potential applications. PMID:17113717

  14. Microfluidic preparation of a highly active and stable catalyst by high performance of encapsulation of polyvinylpyrrolidone (PVP)-Pt nanoparticles in microcapsules.

    PubMed

    Nam, Jin-Oh; Kim, Jongmin; Jin, Si Hyung; Chung, Young-Min; Lee, Chang-Soo

    2016-02-15

    The encapsulation of active metals in microcapsules would be highly advantageous in maintaining or improving the reaction performance of an array of widely used chemical reactions. However, conventional methods suffer from low uniformity, complicated fabrication steps, sintering, leaching, decline of catalytic activity, and/or poor reusability. Here, we report an efficient microfluidic approach to encapsulate Pt nanoparticle stabilized by polyvinylpyrrolidone (PVP) in photocurable double-emulsion droplets with semipermeable thin shells. The encapsulated catalysts are prepared by the in situ photopolymerization of a double emulsion. The rapid and exquisite microfluidics-based fabrication process successfully generates monodisperse microcapsules without loss of the PVP-Pt nanoparticles, which is the first demonstration of the microfluidic encapsulation of active metal with promising catalytic activity. Specifically, compared to quasi-homogeneous catalysis of PVP-Pt nanoparticles for 4-nitrophenol hydrogenation, the encapsulated PVP-Pt nanoparticles demonstrate excellent catalytic activity, a leaching-proof nature, and high reusability under the same reaction conditions. We envision that the approach described here may be an example of elegant catalyst design to efficiently overcome difficult problems in active-metal encapsulation and to dramatically enhance catalytic activity by taking advantage of the unique aspects of microfluidic methods. PMID:26624530

  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.

    PubMed

    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. PMID:26014283

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

    SciTech Connect

    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.

  17. Synthesis and comparative study on the antimicrobial activity of hybrid materials based on silver nanoparticles (AgNps) stabilized by polyvinylpyrrolidone (PVP).

    PubMed

    Bryaskova, Rayna; Pencheva, Daniela; Nikolov, Stanislav; Kantardjiev, Todor

    2011-10-01

    Hybrid materials based on polyvinylpyrrolidone (PVP) with silver nanoparticles (AgNps) were synthesized applying two different strategies based on thermal or chemical reduction of silver ions to silver nanoparticles using PVP as a stabilizer. The formation of spherical silver nanoparticles with diameter ranging from 9 to 16 nm was confirmed by TEM analysis. UV-vis and FTIR spectroscopy were also applied to confirm the successful formation of AgNps. The antibacterial activity of the synthesized AgNPs/PVP against etalon strains of three different groups of bacteria-Staphylococcus aureus (S. aureus; gram-positive bacteria), Escherichia coli (E. coli; gram-negative bacteria), Pseudomonas aeruginosa (P. aeruginosa; non-ferment gram-negative bacteria), as well as against spores of Bacillus subtilis (B. subtilis) was studied. AgNps/PVP were tested for the presence of fungicidal activity against different yeasts and mold such as Candida albicans, Candida krusei, Candida tropicalis, Candida glabrata, and Aspergillus brasiliensis. The hybrid materials showed a strong antimicrobial effect against the tested bacterial and fungal strains and therefore have potential applications in biotechnology and biomedical science. PMID:22837793

  18. Synthesis, characterization and photocatalytic activity of PVP stabilized ZnO and modified ZnO nanostructures

    NASA Astrophysics Data System (ADS)

    Bandekar, Gauri; Rajurkar, N. S.; Mulla, I. S.; Mulik, U. P.; Amalnerkar, D. P.; Adhyapak, P. V.

    2013-01-01

    In the present study, ZnO nanostructures have been successfully synthesized by hydrothermal, sonochemical and precipitation methods using polyvinyl pyrrolidone (PVP) as the capping agent. The ZnO nanoparticles were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), UV-Visible spectroscopy and photoluminescence (PL) techniques. The XRD results revealed the hexagonal wurtzite structure of the ZnO nanostructures for all the samples. Furthermore, the morphology of the ZnO particles was obtained from FESEM micrographs. Particles prepared by hydrothermal method were found to be rice grain shaped and that prepared by precipitation and sonochemical methods were spherical shaped. Sunlight driven photocatalytic degradation of methylene blue (MB) was studied for ZnO nanostructures synthesized by various methods. The ZnO nanostructures were further decorated with Ag nanoparticles to enhance its dye degradation efficiency. The Ag decorated ZnO nanoparticles exhibited a higher degradation rate as compared to pure ZnO nanoparticles which was independent of pH. Since this process of dye degradation relies on the degradation of dye due to oxidation by highly reactive hydroxyl radicals, there are many factors which affect the efficiency of this process. Hence a study was conducted on the effect of various parameters on ZnO viz amount of catalyst, reaction pH and concentration of MB dye.

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

    NASA Astrophysics Data System (ADS)

    Zhou, Ming; Zhou, Jinyuan; Li, Ruishan; Xie, Erqing

    2010-02-01

    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 (SiO x) 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 SiO x 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.

  20. Enhanced separation performance of PVDF/PVP-g-MMT nanocomposite ultrafiltration membrane based on the NVP-grafted polymerization modification of montmorillonite (MMT).

    PubMed

    Wang, Panpan; Ma, Jun; Wang, Zhenghui; Shi, Fengmei; Liu, Qianliang

    2012-03-13

    A novel hydrophilic nanocomposite additive (PVP-g-MMT), coupling of hydrophilic modifier, self-dispersant, and pore-forming agent (porogen), was synthesized by the surface modification of montmorillonite (MMT) with N-vinylpyrrolidone (NVP) via "grafting from" polymerization in the presence of H(2)O(2)-NH(3)·H(2)O as the initiator, and then the nanocomposite membrane of poly(vinylidene fluoride) (PVDF) and PVP-g-MMT was fabricated by wet phase inversion onto clean glass plates. The existence and dispersion of PVP-g-MMT had a great role on structures, morphologies, surface composition, and chemistry of the as-prepared nanocomposite membranes confirmed by varieties of spectroscopic and microscopic characterization techniques, all of which were the correlated functions of PVP-g-MMT content in casting solution. By using the dead-end filtration of protein aqueous solution, the performance of the membrane was evaluated. It was seen that all of the nanocomposite membranes showed obvious improvement of water flux and proper BSA rejection ratio, compared to the control PVDF membrane. Meanwhile, dynamic BSA fouling resistance and flux recovery properties were also greatly enhanced due to the changes of surface hydrophilicity and morphologies. All the experimental results indicated that the as-prepared PVDF nanocomposite membranes showed better separation performances than the control PVDF membrane. Hopefully, the demonstrated method of hydrophilic nanocomposite additive synthesis would be applied for commonly hydroxyl group-containing inorganic nanoparticles, which was favorable to fabricate hydrophilic nanoparticle-enhanced polymer membranes for water treatment. PMID:22376185

  1. Sol–gel auto-combustion synthesis of PVP/CoFe{sub 2}O{sub 4} nanocomposite and its magnetic characterization

    SciTech Connect

    Kurtan, U.; Topkaya, R.; Baykal, A.

    2013-11-15

    Graphical abstract: - Highlights: • The Poly(vinyl pyrrolidone) (PVP) was used as a surface capping agent. • PVP/CoFe{sub 2}O{sub 4} nanocomposite was synthesized by a sol-gel auto-combustion method. • The existence of the spin-disordered surface layer was established. - Abstract: Poly(vinyl pyrrolidone)/CoFe{sub 2}O{sub 4} nanocomposite has been fabricated by a sol–gel auto-combustion method. Poly(vinyl pyrrolidone) was used as a reducing agent as well as a surface capping agent to prevent particle aggregation and stabilize the particles. The average crystallite size estimated from X-ray line profile fitting was found to be 20 ± 7 nm. The high field irreversibility and unsaturated magnetization behaviours indicate the presence of the core–shell structure in the sample. The exchange bias effect observed at 10 K suggests the existence of the magnetically aligned core surrounded by spin-disordered surface layer. The reduced remanent magnetization value of 0.6 at 10 K (higher than the theoretical value of 0.5) shows the PVP/CoFe{sub 2}O{sub 4} nanocomposite to have cubic magnetocrystalline anisotropy according to the Stoner–Wohlfarth model.

  2. Effect of reductant and PVP on morphology and magnetic property of ultrafine Ni powders prepared via hydrothermal route

    SciTech Connect

    Zhang, Jun Wang, Xiucai; Li, Lili; Li, Chengxuan; Peng, Shuge

    2013-10-15

    Graphical abstract: The ultrafine Ni powders with the shapes including sphere, pearl-string, leaf, fish-bone, hexagonal sheet and silknet were prepared through one-step hydrothermal reduction using different reductants. Their saturation magnetization, remanent magnetization and coercivity sequentially increase, and the coercivity of hexagonal sheet-like Ni powders increases by 25% compared with the Ni bulk counterpart. - Highlights: • The ultrafine Ni powders with various shapes of sphere, fish-bone, hexagonal sheet, etc. • Facile and one-step hydrothermal reduction using three reductants and PVP additive was developed. • Magnetic properties of the ultrafine Ni powders with different shapes were measured. • Compared with bulk Ni material, coercivity of hexagonal sheet Ni increases by 25%. • The formation mechanism of the shapes was suggested. - Abstract: The ultrafine nickel particles with different shapes including sphere, pearl-string, leaf, fish-bone, hexagonal sheet and silknet were prepared through one-step hydrothermal reduction using hydrazine hydrate, sodium hypophosphite and ethylene glycol as reductants, polyvinylpyrrolidone as structure-directing agent. It has been verified with the characterization of X-ray powder diffraction and transmission/scanning electronic microscopy that as-prepared products belong to face-centered cubic structure of nickel microcrystals with high purity and fine dispersity. The magnetic hysteresis loops measured at room temperature reveal that the values of saturation magnetization, remanent magnetization and coercivity rise sequentially from silknet, sphere to hexagonal sheet. In comparison with nickel bulk counterpart, the coercivity of the hexagonal sheet nickel powders increases by 25%.

  3. Effects of reaction time and citric acid contents on the morphologies of BaCO{sub 3} via PVP-assisted method

    SciTech Connect

    Lv Sa; Sheng Jie; Zhang Shuang; Sun Wendong

    2008-05-06

    BaCO{sub 3} with different morphologies, such as dumbbell-like, pillar-like, peanut-like and ellipsoid-like have been successfully synthesized using citric acid (CA) as chelating ligand via a simple polyvinylpyrrolidone (PVP)-assisted method. The effects of the pH of the starting solutions, reaction time and the molar ratio of CA/Ba{sup 2+} on the morphologies of BaCO{sub 3} were investigated. X-ray diffraction (XRD), transmission electron microscope (TEM) and the infrared (IR) spectrum of the sample are used to characterize the obtained products.

  4. Photoselective vaporization of the prostate (PVP) with green light KTP laser in the management of symptomatic benign prostatic enlargement (BPE): does the anatomy of the TURP-like cavity predict the clinical outcome?

    NASA Astrophysics Data System (ADS)

    Nseyo, Unyime

    2005-04-01

    Photoselective vaporization of the prostate (PVP) is evolving as an alternative outpatient surgical treatment to transurethral resection of the prostate (TURP) in the management of patients with symptomatic benign prostatic hypertrophy/enlargement (BPH/BPE). The purported benefits of PVP include rapid vaporization of the prostate with an instant creation of TURP-like anatomic defect, an excellent hemostasis, shorter (<24 hours) duration of catheterization, short (< 24 hours) hospital stay, and quick return to work. We retrospectively reviewed the video clips of our cases to determine whether or not the anatomic appearance of the post-PVP prostatic cavity per se could predict clinical outcome. Forty-three, non-consecutive patients, diagnosed with symptomatic BPH have been treated with PVP using the 80W KTP laser and followed for at least 18 months (range 18-24). A majority (N=32) of the patients was enrolled under an Institutional Review Board approved multi-center protocol at the Hunter McGuire Veterans Administration Medical Center, Richmond, Virginia. We reviewed the urodynamic parameters: AUA-SI, QOL, Qmax and PVR at 3, 6, 12, 18 and 24 months postoperatively. We plan to present video documentations of the various anatomic appearances of the TURP-like prostatic cavity at the conclusion of the PVP treatment along with summaries of the short and long term clinical outcomes.

  5. PVP Assisted Shape-Controlled Synthesis of Self-Assembled 1D ZnO and 3D CuO Nanostructures

    NASA Astrophysics Data System (ADS)

    Haque, Fozia Z.; Parra, Mohammad Ramzan; Siddiqui, Hafsa; Singh, Neha; Singh, Nitu; Pandey, Padmini; Mishra, K. M.

    2016-03-01

    Self-assembled one-dimensional (1D) zinc oxide (ZnO) rods and three-dimensional (3D) cupric oxide (CuO) cubes like nanostructures with a mean crystallite size of approximately 33 and 32 nm were synthesized through chemical route in the presence of polyvinylpyrrolidone (PVP) under mild synthesis conditions. The technique used for the synthesis of nanoparticles seems to be an efficient, inexpensive and easy method. X-Ray diffraction patterns confirmed well crystallinity and phase purity of the as prepared samples, followed by the compositional investigation using Fourier Transform Infrared (FT-IR) spectroscopy. The formation of ZnO nanorods and CuO nanocubes like structures were through Scanning Electron Microscopy (SEM) images. The mechanism and the formation factors of the self-assembly were discussed in detail. It was clearly observed from results that the concentration of precursors and PVP were important factors in the synthesis of self-assembly ZnO and CuO nanostructures. These self-assembly nanostructures maybe used as novel materials in various potential applications.

  6. Characterization of CH3SO3H-doped PMMA/PVP blend-based proton-conducting polymer electrolytes and its application in primary battery

    NASA Astrophysics Data System (ADS)

    Ambika, C.; Hirankumar, G.

    2016-02-01

    Various compositions of solid blend polymer electrolytes based on poly(methyl methacrylate) (PMMA)/poly(vinyl pyrrolidone) (PVP) complexed with methanesulfonic acid (MSA) as proton donor were prepared by solution casting technique. The complex nature of polymer blend with MSA was confirmed by Fourier transform infrared spectroscopy. Good thermal stability of PMMA/PVP blend polymer electrolyte was identified by thermogravimetric analysis. The surface morphology of the prepared electrolytes was studied through optical microscopy. Ion transport number was determined in the range of 0.93-0.97 for proton-conducting blend polymer electrolytes. The maximum conductivity value was calculated as 2.51 × 10-5 S/cm at 303 K for 14.04 mol% MSA-doped polymer electrolytes. Dielectric studies were also carried out. The electrochemical stability window of blend polymer electrolyte was found to be 1.82 V. Primary proton battery was fabricated with Zn + ZnSO4·7H2O/solid polymer electrolytes/MnO2. The discharge characteristics were studied at constant current drain of 5, 20 and 50 μA. The energy and power density were calculated as 0.27 W h kg-1 and 269.23 mW kg-1 for 20 μA of discharge, respectively.

  7. Novel strategy for f-HAp/PVP/Ag nanocomposite synthesis from fluoro based ionic liquid assistance: Systematic investigations on its antibacterial and cytotoxicity behaviors.

    PubMed

    Jegatheeswaran, S; Selvam, S; Sri Ramkumar, V; Sundrarajan, M

    2016-10-01

    A novel biomimetic f-HAp/PVP/Ag nanocomposite was synthesized under the ionic liquid medium, which was composed of inorganic and organic nanofillers like fluor-hydroxyapatite, silver nanoparticles and polyvinyl pyrrolidone. In composite synthesis, the first time we were used fluorine based ionic liquid for the fluorine contents on the fluor-hydroxyapatite nanoparticles which were resulting in very good crosslinking and interfacial bonding with the PVP and Ag nanoparticles. Ionic liquid has assisted good morphological structure of both inorganic materials. The chemical interaction and crystallinity changes of the nanocomposite were evaluated by FTIR and XRD studies. The surface morphology and composition of the samples were observed by FE-SEM, HR-TEM and EDS analyses. This report reveals that the greener approach for synthesis of fluor-hydroxyapatite nanocomposite and sustained delivery of silver and fluorine ions from the fluor-hydroxyapatite surface to the bacterial surface have been reducing the bacterial growth rate which was evaluated by different pathogenic bacterial strains via different methods and it also favourable cytotoxicity effect with human osteosarcoma (MG-63) cells. PMID:27287093

  8. 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.

    PubMed

    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. PMID:23359268

  9. A simple, fast, and inexpensive CTAB-PVP-silica based method for genomic DNA isolation from single, small insect larvae and pupae.

    PubMed

    Huanca-Mamani, W; Rivera-Cabello, D; Maita-Maita, J

    2015-01-01

    In this study, we report a modified CTAB-PVP method combined with silicon dioxide (silica) treatment for the extraction of high quality genomic DNA from a single larva or pupa. This method efficiently obtains DNA from small specimens, which is difficult and challenging because of the small amount of starting tissue. Maceration with liquid nitrogen, phenol treatment, and the ethanol precipitation step are eliminated using this methodology. The A260/A280 absorbance ratios of the isolated DNA were approximately 1.8, suggesting that the DNA is pure and can be used for further molecular analysis. The quality of the isolated DNA permits molecular applications and represents a fast, cheap, and effective alternative method for laboratories with low budgets. PMID:26214482

  10. Freeze-dried PVP-Ag+ precursors to novel AgBr/AgCl-Ag hybrid nanocrystals for visible-light-driven photodegradation of organic pollutants

    NASA Astrophysics Data System (ADS)

    Chen, Deliang; Chen, Qianqian; Zhang, Wenjie; Ge, Lianfang; Shao, Gang; Fan, Bingbing; Lu, Hongxia; Zhang, Rui; Yang, Daoyuan; Shao, Guosheng

    2015-04-01

    AgBr/AgCl-Ag nanocrystals with various molar Br-to-Ag ratios (RBr/Ag = 0, 1/3, 1/2, 2/3, 1) and different photoreduction times (0-20 min) were synthesized via stepwise liquid-solid reactions using the freeze-dried PVP-Ag+ hybrid as the Ag source, followed by a photoreduction reaction. The AgBr/AgCl-Ag7.5(1:2) nanocrystals obtained take on a spherical morphology with a particle-size range of 58 ± 15 nm. The photocatalytic performance of AgBr/AgCl-Ag nanocrystals was evaluated by photodegrading organic dyes, 4-chlorophenol and isopropanol under artificial visible light (λ ⩾ 420 nm, 100 mW cm-2). For the decomposition of rhodamine B, the AgBr/AgCl-Ag7.5(1:2) nanocrystals has a photodegradation rate of ∼0.87 min-1, ∼159 times higher than that (∼0.0054 min-1) of TiO2 (P25), whereas the AgCl-Ag and AgBr-Ag nanocrystals have photodegradation rates of 0.35 min-1 and 0.45 min-1, respectively. The efficient separation of photogenerated electron-hole pairs in the ternary system consisting of AgBr, AgCl and Ag species plays a key role in the enhancement of photocatalytic performance.

  11. PVP-Assisted Synthesis of Uniform Carbon Coated Li2S/CB for High-Performance Lithium-Sulfur Batteries.

    PubMed

    Chen, Lin; Liu, Yuzi; Zhang, Fan; Liu, Caihong; Shaw, Leon L

    2015-11-25

    The lithium-sulfur (Li-S) battery is a great alternative to the state-of-the-art lithium ion batteries due to its high energy density. However, low utilization of active materials, the insulating nature of sulfur or lithium sulfide (Li2S), and polysulfide dissolution in organic liquid electrolyte lead to low initial capacity and fast performance degradation. Herein, we propose a facile and viable approach to address these issues. This new approach entails synthesis of Li2S/carbon black (Li2S/CB) cores encapsulated by a nitrogen-doped carbon shell with polyvinylpyrrolidone (PVP) assistance. Combining energy-filtered transmission electron microscopy (EFTEM) elemental mappings, XPS and FTIR measurements, it is confirmed that the as-synthesized material has a structure of a Li2S/CB core with a nitrogen-doped carbon shell (denoted as Li2S/CB@NC). The Li2S/CB@NC cathode yields an exceptionally high initial capacity of 1020 mAh/g based on Li2S mass at 0.1 C with stable Coulombic efficiency of 99.7% over 200 cycles. Also, cycling performance shows the capacity decay per cycle as small as 0.17%. Most importantly, to further understand the materials for battery applications, field emission transmission electron microscopy (FETEM) and elemental mapping tests without exposure to air for Li2S samples in cycled cells are reported. Along with the first ever FETEM and field emission scanning electron microscopy (FESEM) investigations of cycled batteries, Li2S/CB@NC cathode demonstrates the capability of robust core-shell nanostructures for different rates and improved capacity retention, revealing Li2S/CB@NC designed here as an outstanding system for high-performance lithium-sulfur batteries. PMID:26529481

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

    PubMed

    Ahlberg, Sebastian; Antonopulos, Alexandra; Diendorf, Jörg; Dringen, Ralf; Epple, Matthias; Flöck, Rebekka; Goedecke, Wolfgang; Graf, Christina; Haberl, Nadine; Helmlinger, Jens; Herzog, Fabian; Heuer, Frederike; Hirn, Stephanie; Johannes, Christian; Kittler, Stefanie; Köller, Manfred; Korn, Katrin; Kreyling, Wolfgang G; Krombach, Fritz; Lademann, Jürgen; Loza, Kateryna; Luther, Eva M; Malissek, Marcelina; Meinke, Martina C; Nordmeyer, Daniel; Pailliart, Anne; Raabe, Jörg; Rancan, Fiorenza; Rothen-Rutishauser, Barbara; Rühl, Eckart; Schleh, Carsten; Seibel, Andreas; Sengstock, Christina; Treuel, Lennart; Vogt, Annika; Weber, Katrin; Zellner, Reinhard

    2014-01-01

    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 harmful to skin

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

    PubMed Central

    Ahlberg, Sebastian; Antonopulos, Alexandra; Diendorf, Jörg; Dringen, Ralf; Flöck, Rebekka; Goedecke, Wolfgang; Graf, Christina; Haberl, Nadine; Helmlinger, Jens; Herzog, Fabian; Heuer, Frederike; Hirn, Stephanie; Johannes, Christian; Kittler, Stefanie; Köller, Manfred; Korn, Katrin; Kreyling, Wolfgang G; Krombach, Fritz; Lademann, Jürgen; Loza, Kateryna; Luther, Eva M; Malissek, Marcelina; Meinke, Martina C; Nordmeyer, Daniel; Pailliart, Anne; Raabe, Jörg; Rancan, Fiorenza; Rothen-Rutishauser, Barbara; Rühl, Eckart; Schleh, Carsten; Seibel, Andreas; Sengstock, Christina; Treuel, Lennart; Vogt, Annika; Weber, Katrin; Zellner, Reinhard

    2014-01-01

    Summary 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 harmful

  14. 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.

    PubMed

    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. PMID:26890319

  15. Seismic engineering -- 1996. PVP-volume 340

    SciTech Connect

    Saleem, M.A.; Aggarwal, M.C.

    1996-12-01

    The 37 papers in this volume have been arranged under the following topical sections: advanced methods in seismic engineering (7 papers); high level dynamic response of piping systems (5); equipment seismic qualification (6); soil structure interaction (3); advanced seismic technology in Asian countries (8); developments in seismic codes and standards (8); and a panel discussion on the review of current issues by the Special Working Group on seismic rules. Papers have been processed separately for inclusion on the data base.

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

    SciTech Connect

    Hulbert, G.M.; Hsu, K.H.; Lee, T.W.; Nicholas, T.

    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.

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

    PubMed

    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 (<10 nm) were simply synthesized using polyvinylpyrrolidone as the capping agent as well as the reductant. The morphology of the PBS-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. PMID:24013858

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

    NASA Technical Reports Server (NTRS)

    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.

  19. Pressure vessels and piping codes and standards: Volume 1. PVP-Volume 338

    SciTech Connect

    Esselman, T.C.; Adams, T.M.; Bhavnani, D.; Cofie, N.G.; Jones, D.P.; Olson, D.E.; Thailer, H.J.

    1996-12-01

    The role of Codes and Standards for pressure vessels and piping has increased significantly over the past decade. More and more, developments in Codes and Standards are accommodating the increasing sophistication of analysis methods, the need to address post-construction and operating plant issues, and the efficiencies that may be gained by focusing codes and standards on the areas that present the greatest risk. Codes and Standards for new construction also have had to accommodate greater challenges and more extreme environments imposed by more escalating requirements on piping and pressure vessel design and fabrication. This volume on Codes and Standards has focused on these challenges faced by Codes and Standards development. The topics in this volume include: (1) Socket Welds and Stress Intensification Factors; (2) Developments in Piping Code and Standards; (3) Root Cause Analysis; (4) B31.1 Code Developments and Applications; (5) Flow-Accelerated Corrosion Developments and Applications; (6) Advanced Analysis Methods and the ASME Code; and (7) Application of Advanced Analysis Methods for ASME Code Evaluation. Separate abstracts were prepared for most of the papers in this volume.

  20. Nanostructured Drugs Embedded into a Polymeric Matrix: Vinpocetine/PVP Hybrids Investigated by Debye Function Analysis.

    PubMed

    Hasa, Dritan; Giacobbe, Carlotta; Perissutti, Beatrice; Voinovich, Dario; Grassi, Mario; Cervellino, Antonio; Masciocchi, Norberto; Guagliardi, Antonietta

    2016-09-01

    Microcrystalline vinpocetine, coground with cross-linked polyvinylpyrrolidone, affords hybrids containing nanosized drug nanocrystals, the size and size distributions of which depend on milling times and drug-to-polymer weight ratios. Using an innovative approach to microstructural characterization, we analyzed wide-angle X-ray total scattering data by the Debye function analysis and demonstrated the possibility to characterize pharmaceutical solid dispersions obtaining a reliable quantitative view of the physicochemical status of the drug dispersed in an amorphous carrier. The microstructural properties derived therefrom have been successfully employed in reconciling the enigmatic difference in behavior between in vitro and in vivo solubility tests performed on nanosized vinpocetine embedded in a polymeric matrix. PMID:27428180

  1. Pressure vessels and piping codes and standards: Volume 2. PVP-Volume 339

    SciTech Connect

    Esselman, T.C.; Balkey, K.; Chao, K.K.N.; Gosselin, S.; Hollinger, G.; Lubin, B.T.; Mohktarain, K.; O`Donnell, W.; Rao, K.R.

    1996-12-01

    The role of Codes and Standards for pressure vessels and piping has increased significantly over the past decade. More and more, developments in Codes and Standards are accommodating the increasing sophistication of analysis methods, the need to address post-construction and operating plant issues, and the efficiencies that may be gained by focusing codes and standards on the areas that present the greatest risk. Codes and Standards for new construction also have had to accommodate greater challenges and more extreme environments imposed by more escalating requirements on piping and pressure vessel design and fabrication. This volume has focused on these challenges faced by Codes and Standards development. The topics in this volume include: (1) International Code Developments; (2) Seismic Developments in Codes and Standards; (3) Fabrication, Repairs, and Installation Issues Relating to Codes and Standards; (4) Application of Risk Based Criteria to In-Service Inspections; (5) Risk Based Codes and Standards; (6) The Code--Then and Now; (7) Reactor Water Fatigue: Fitness for Service; and (8) Two ASME Pressure Technology Code Issues: Post-Construction Codes and Metrication. Separate abstracts were prepared for most of the papers in this volume.

  2. Single molecule detection using SERS study in PVP functionalized Ag nanoparticles

    NASA Astrophysics Data System (ADS)

    Garg, Parul; Dhara, S.

    2013-02-01

    Non-spherical functionalized Ag nanoparticles (NPs) with homogenous size ˜ 40 nm have been grown using soft chemical route. Solution of silver nitrate and polyvinylpyrrolidone is reduced in excess of ethylene glycol for the preparation of the NPs. Substrates has been prepared by dip coating of the NPs on c-Si for Raman studies. Rhodamine (R6G) is used as a test molecule to study the surface enhanced Raman spectroscopy (SERS) effect. A single molecule detection of R6G along with an enhancement factor of ˜ 4×103 orders of magnitude in the intensity, for the concentration as low as 10-12 M using polymer coated Ag NPs as SERS substrates, has been achieved.

  3. Synthesis, characterization, and magnetic properties of monodisperse CeO2 nanospheres prepared by PVP-assisted hydrothermal method

    PubMed Central

    2012-01-01

    Ferromagnetism was observed at room temperature in monodisperse CeO2 nanospheres synthesized by hydrothermal treatment of Ce(NO3)3·6H2O using polyvinylpyrrolidone as a surfactant. The structure and morphology of the products were characterized by X-ray diffraction (XRD), Raman spectroscopy, transmission electron microscopy, high-resolution transmission electron microscopy, and field-emission scanning electron microscopy (FE-SEM). The optical properties of the nanospheres were determined using UV and visible spectroscopy and photoluminescence (PL). The valence states of Ce ions were also determined using X-ray absorption near edge spectroscopy. The XRD results indicated that the synthesized samples had a cubic structure with a crystallite size in the range of approximately 9 to 19 nm. FE-SEM micrographs showed that the samples had a spherical morphology with a particle size in the range of approximately 100 to 250 nm. The samples also showed a strong UV absorption and room temperature PL. The emission might be due to charge transfer transitions from the 4f band to the valence band of the oxide. The magnetic properties of the samples were studied using a vibrating sample magnetometer. The samples exhibited room temperature ferromagnetism with a small magnetization of approximately 0.0026 to 0.016 emu/g at 10 kOe. Our results indicate that oxygen vacancies could be involved in the ferromagnetic exchange, and the possible mechanism of formation was discussed based on the experimental results. PMID:22849756

  4. Transformation of PVP coated silver nanoparticles in a simulated wastewater treatment process and the effect on microbial communities

    PubMed Central

    2013-01-01

    Background Manufactured silver nanoparticles (AgNPs) are one of the most commonly used nanomaterials in consumer goods and consequently their concentrations in wastewater and hence wastewater treatment plants are predicted to increase. We investigated the fate of AgNPs in sludge that was subjected to aerobic and anaerobic treatment and the impact of AgNPs on microbial processes and communities. The initial identification of AgNPs in sludge was carried out using transmission electron microscopy (TEM) with energy dispersive X-ray (EDX) analysis. The solid phase speciation of silver in sludge and wastewater influent was then examined using X-ray absorption spectroscopy (XAS). The effects of transformed AgNPs (mainly Ag-S phases) on nitrification, wastewater microbial populations and, for the first time, methanogenesis was investigated. Results Sequencing batch reactor experiments and anaerobic batch tests, both demonstrated that nitrification rate and methane production were not affected by the addition of AgNPs [at 2.5 mg Ag L-1 (4.9 g L-1 total suspended solids, TSS) and 183.6 mg Ag kg -1 (2.9 g kg-1 total solids, TS), respectively]. The low toxicity is most likely due to AgNP sulfidation. XAS analysis showed that sulfur bonded Ag was the dominant Ag species in both aerobic (activated sludge) and anaerobic sludge. In AgNP and AgNO3 spiked aerobic sludge, metallic Ag was detected (~15%). However, after anaerobic digestion, Ag(0) was not detected by XAS analysis. Dominant wastewater microbial populations were not affected by AgNPs as determined by DNA extraction and pyrotag sequencing. However, there was a shift in niche populations in both aerobic and anaerobic sludge, with a shift in AgNP treated sludge compared with controls. This is the first time that the impact of transformed AgNPs (mainly Ag-S phases) on anaerobic digestion has been reported. Conclusions Silver NPs were transformed to Ag-S phases during activated sludge treatment (prior to anaerobic digestion). Transformed AgNPs, at predicted future Ag wastewater concentrations, did not affect nitrification or methanogenesis. Consequently, AgNPs are very unlikely to affect the efficient functioning of wastewater treatment plants. However, AgNPs may negatively affect sub-dominant wastewater microbial communities. PMID:23497481

  5. Structural and optical properties of PVP-capped nanocrystalline ZnxCd1-xS solid solutions

    NASA Astrophysics Data System (ADS)

    Askari, Mina; Soltani, Nayereh; Saion, Elias; Yunus, W. Mahmood Mat; Maryam Erfani, H.; Dorostkar, Mahdi

    2015-05-01

    Nanocrystalline ZnxCd1-xS solid solutions were prepared in a microwave-assisted hydrothermal process with gradient distribution of components (x = 0.1, 0.3, 0.5, 0.7, and 0.9). The growth of the cubic-structured quantum dots was observed for all component stoichiometries with the crystallite size between 4.5 and 5.7 nm. The obvious peak shifts have been found in the XRD patterns and the lattice parameters showed linear variation with x increasing. The evolution of the optical properties of obtained solid solutions including absorption and photoemission was also monitored in detail. The solid solutions show a considerable shift in the nanoparticle optical absorption edge from 482 to 343 nm with the increasing of Zn fraction. The band gaps of the solid solutions were estimated to be between 2.94 and 3.40 eV and the position of conduction band was shifted toward more negative potential with x increasing. The photoluminescence spectra showed a broad blue-green emission spreading up to 600 nm with emergence of three dominant peaks belong to sulfur, zinc, and cadmium vacancies.

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

    PubMed

    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. PMID:26981531

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

    PubMed Central

    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. PMID:26981531

  8. 3D Hierarchical Bi2S 3 Nanostructures by Polyvinylpyrrolidone (PVP) and Chloride Ion-Assisted Synthesis and Their Photodetecting Properties.

    PubMed

    Ding, Taotao; Dai, Jiangnan; Xu, Juan; Wang, Jin; Tian, Wu; Huo, Kaifu; Fang, Yanyan; Chen, Changqing

    2015-12-01

    A solvothermal method has been employed to synthesize bismuth sulfide (Bi2S3) with three-dimensional (3D) hierarchical architectures. The influences of different types of surfactants and Cl(-) species on the size and morphology were investigated. A possible formation mechanism was also proposed on the basis of time-dependent experiments. The photoresponse properties show that the conductivity of Bi2S3 micro-flowers is significantly enhanced and the photocurrent is approximately two orders of magnitude larger than the dark current. The response and decay times are estimated to be 142 and 151 ms, respectively. It is expected that hierarchical architectures Bi2S3 may provide a new pathway to develop advanced nanomaterial for high-speed and high-sensitivity photoelectrical switches and photodetecting devices. PMID:26156218

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

    NASA Technical Reports Server (NTRS)

    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.

  10. Virus-induced gene silencing of PEAM4 affects floral morphology by altering the expression pattern of PsSOC1a and PsPVP in pea.

    PubMed

    Chen, Zhe-Hao; Jia, Fei-Fei; Hu, Jiang-Qin; Pang, Ji-Liang; Xu, Lei; Wang, Li-Lin

    2014-01-15

    pea-MADS4 (PEAM4) regulates floral morphology in Pisum sativum L., however, its molecular mechanisms still remain unclear. Virus-induced gene silencing (VIGS) is a recently developed reverse genetic approach that facilities an easier and more rapid study of gene functions. In this study, the PEAM4 gene was effectively silenced by VIGS using a pea early browning virus (PEBV) in wild type pea JI992. The infected plants showed abnormal phenotypes, as the floral organs, especially the sepals and petals changed in both size and shape, which made the corolla less closed. The petals changed in morphology and internal symmetry with, the stamens reduced and carpel dehisced. Larger sepals and longer tendrils with small cauline leaves appeared, with some sepals turning into bracts, and secondary inflorescences with fused floral organs were formed, indicating a flower-to-inflorescence change. The infected plants also displayed a delayed and prolonged flowering time. The PEAM4-VIGS plants with altered floral morphology were similar to the pim (proliferating inflorescence meristem) mutant and also mimicked the phenotypes of ap1 mutants in Arabidopsis. The expression pattern of the homologous genes PsSOC1a and PsSVP, which were involved in flowering time and florescence morphological control downstream of PEAM4, were analyzed by real-time RT-PCR and mRNA in situ hybridization. PsSOC1a and PsSVP were ectopically expressed and enhanced in the floral meristems from PEAM4-silenced plants. Our data suggests that PEAM4 may have a similar molecular mechanism as AtAP1, which inhibits the expression of PsSOC1a and PsSVP in the floral meristem from the early stages of flower development. As such, in this way PEAM4 plays a crucial role in maintaining floral organ identity and flower development in pea. PMID:24331430

  11. 3D Hierarchical Bi2S3 Nanostructures by Polyvinylpyrrolidone (PVP) and Chloride Ion-Assisted Synthesis and Their Photodetecting Properties

    NASA Astrophysics Data System (ADS)

    Ding, Taotao; Dai, Jiangnan; Xu, Juan; Wang, Jin; Tian, Wu; Huo, Kaifu; Fang, Yanyan; Chen, Changqing

    2015-07-01

    A solvothermal method has been employed to synthesize bismuth sulfide (Bi2S3) with three-dimensional (3D) hierarchical architectures. The influences of different types of surfactants and Cl- species on the size and morphology were investigated. A possible formation mechanism was also proposed on the basis of time-dependent experiments. The photoresponse properties show that the conductivity of Bi2S3 micro-flowers is significantly enhanced and the photocurrent is approximately two orders of magnitude larger than the dark current. The response and decay times are estimated to be 142 and 151 ms, respectively. It is expected that hierarchical architectures Bi2S3 may provide a new pathway to develop advanced nanomaterial for high-speed and high-sensitivity photoelectrical switches and photodetecting devices.

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

    PubMed

    Mojib, Nazia; Farhoomand, Amin; Andersen, Dale T; Bej, Asim K

    2013-05-01

    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. PMID:23512118

  13. 7 CFR 91.5 - Where services are offered.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... Protection (PVP) Office. The PVP office and plant examination facility of the Science and Technology programs.... The PVP office is located as follows: USDA, AMS, Science & Technology Programs, Plant Variety... offered to applicants at the Science and Technology laboratories and facilities as listed below....

  14. Enhancing the quality of transferred single-layer graphene with poly(4-vinylphenol) interlayer on flexible substrates

    NASA Astrophysics Data System (ADS)

    Choi, Yeonhoi; Chun, Sungwoo; Hong, Ahyoung; Ha, Chunho; Park, Wanjun

    2016-06-01

    We report the use of poly(4-vinylphenol) (PVP) as a promising contact surface of transferred graphene, capable of sustaining the original performance found in as-grown graphene. Enhancement of surface tension obtained by O2 plasma treatment of the PVP surface also increases transferred graphene quality. With an easy coating method, PVP can be applied to any flexible substrate as the interlayer to increase transferred graphene quality. Owing to the mechanical flexibility and chemical inertness of PVP, the introduction of a PVP interlayer provides a general method for graphene soft electronics to be integrated into any flexible substrate.

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

    NASA Astrophysics Data System (ADS)

    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.

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

    SciTech Connect

    Ooi, Mahayatun Dayana Johan; Aziz, Azlan Abdul

    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.

  17. How transplant surgeons can overcome the inevitable insufficiency of allograft size during adult living-donor liver transplantation: strategy for donor safety with a smaller-size graft and excellent recipient results.

    PubMed

    Hori, Tomohide; Ogura, Yasuhiro; Ogawa, Kohei; Kaido, Toshimi; Segawa, Hajime; Okajima, Hideaki; Kogure, Takayuki; Uemoto, Shinji

    2012-01-01

    Small-for-size grafts are an issue in liver transplantation. Portal venous pressure (PVP) was monitored and intentionally controlled during living-donor liver transplantation (LDLT) in 155 adult recipients. The indocyanine green elimination rate (kICG) was simultaneously measured in 16 recipients and divided by the graft weight (g) to reflect portal venous flow (PVF). The target PVP was <20 mmHg. Patients were divided by the final PVP (mmHg): Group A, PVP < 12; Group B, 12 ≤ PVP < 15; Group C, 15 ≤ PVP < 20; and Group D, PVP ≥ 20. With intentional PVP control, we performed splenectomy and collateral ligation in 80 cases, splenectomy in 39 cases, and splenectomy, collateral ligation, and additional creation in five cases. Thirty-one cases received no modulation. Groups A and B showed good LDLT results, while Groups C and D did not. Final PVP was the most important factor for the LDLT results, and the PVP cutoffs for good outcomes and clinical courses were both 15.5 mmHg. The respective kICG/graft weight cutoffs were 3.5580 × 10(-4) /g and 4.0015 × 10(-4) /g. Intentional PVP modulation at <15 mmHg is a sure surgical strategy for small-for-size grafts, to establish greater donor safety with good LDLT results. The kICG/graft weight value may have potential as a parameter for optimal PVF and a predictor for LDLT results. PMID:22686957

  18. Interaction between water and poly(vinylpyrrolidone) containing polyethylene glycol.

    PubMed

    Hamaura, T; Newton, J M

    1999-11-01

    Information on the interaction between water and polymers is indispensable for manufacturing solid dispersion of a drug by hot-melt extrusion because this interaction affects various properties of the water-polymer mixtures, such as their viscoelastic properties. In this study, poly(vinylpyrrolidone) K30 (PVP) containing 0%, 10%, and 20% poly(ethylene glycol) 400 (PEG) was used as model amorphous polymers. The interaction of water with these polymers was assessed by the evaluation of the glass transition temperature (Tg), the point on the isotherm corresponding to the weight of sorbed water required to form a complete monolayer on the solid surface (apparent Wm), and the maximal amount of nonfreezing water, which were measured by differential scanning calorimetry and water sorption isotherms. In all of the systems with a water content below a certain water fraction (0.1 for PVP, 0.12 for PVP-PEG 10%, and 0.16 for PVP-PEG 20%), the Tg values were successfully predicted using theoretical equations, whereas the experimental Tg values were higher than predicted for those with a water content above these water fraction levels. In addition, these values of water fraction are similar to the apparent W(m) values determined using the Guggenheim-Anderson-DeBoer (GAB) equation (0.110, 0.117, and 0.147 weight fraction of water for PVP, PVP-PEG 10%, and PVP-PEG 20%, respectively). Nonfreezing water is detected above 0.47, 0.49, and 0.51 weight fraction of water for PVP, PVP-PEG 10%, and PVP-PEG 20%, respectively. Miscibility between water and PVP or PVP-PEG seems to change according to the water content in the system. All parameters increase with the concentration of PEG in the sample. This may be explained by the fact that PEG has a larger number of polymer repeating units, which may therefore interact with water more than PVP. PMID:10564074

  19. Harnessing nonlinear rubber swelling for bulk synthesis of anisotropic hybrid nanoparticles† †Electronic supplementary information (ESI) available: The TEM images of control Au–PDVB hybrid nanoparticles formed without the presence of PVP and Au–PS hybrid nanoparticles. See DOI: 10.1039/c4tc01660b Click here for additional data file.

    PubMed Central

    Baumberg, Jeremy J.

    2014-01-01

    Asymmetric hybrid nanoparticles are at the forefront of colloidal chemistry as building blocks for novel structures and applications, as well as for exploring fundamental ways of breaking symmetry in physical systems. Current methods of synthesis have significant limitations in terms of control over synthesis, particle size ranges and polydispersity. We report a facile and scalable synthesis based on the anisotropic swelling of rubber to obtain metal–(polymer rubber) hybrid nanoparticles. Initial Au nanoparticle (NP) seeds are grown larger by reducing HAuCl4 with divinyl benzene (DVB), while simultaneous radical polymerization of DVB forms a cross-linked rubber layer of PDVB on the Au NP surface. The propensity of rubber to swell nonlinearly in the presence of DVB monomers amplifies initial asymmetries to break the symmetry of the PDVB shell, causing growth of asymmetric protrusions on one side of the core–shell particles, which are fixed by further polymerization. Plasmonic absorption of Au allows us to follow the Au reduction reaction and also suggests potential applications of some of the asymmetric particles in plasmon-enhanced sensing. The polydispersity, determined statistically from TEM and SEM images, of the resulting particles is low (<10%) and their sizes, shapes and metal–polymer ratios are easily tunable. PMID:27358735

  20. Poly(vinylpyrrolidone) for bioconjugation and surface ligand immobilization.

    PubMed

    Zelikin, Alexander N; Such, Georgina K; Postma, Almar; Caruso, Frank

    2007-09-01

    Poly(vinylpyrrolidone) (PVP), a nonionic and nontoxic polymer with antifouling properties, has been synthesized via RAFT polymerization to obtain thiol-terminated PVP. We demonstrate that when the polymer is adsorbed onto the surface of colloidal silica particles, the terminal thiol groups of PVP remain accessible for chemical modification and lend themselves to the immobilization of ligands. We show that ligand attachment onto the surface via conjugation to PVP is reversible, as the polymer can be desorbed from the surface for conjugate and surface recovery. We present the conjugation of a model peptide and an oligonucleotide to PVP via the polymer terminal thiol and demonstrate that conjugates remain functional in molecular recognition assay. The developed technique offers a novel method to functionalize low-fouling surfaces for a variety of biomedical applications and presents opportunities to use PVP as a macromolecular drug carrier. PMID:17715962

  1. Chitosan/poly (vinyl pyrollidone) coatings improve the antibacterial properties of poly(ethylene terephthalate)

    NASA Astrophysics Data System (ADS)

    Wang, Bai-liang; Wang, Jin-lei; Li, Dan-dan; Ren, Ke-feng; Ji, Jian

    2012-08-01

    Chitosan/poly (vinyl pyrollidone) (CHI/PVP) coatings were prepared to improve the antibacterial properties of poly (ethylene terephthalate) (PET) by a simple dip-coating method. The binding capability of CHI/PVP coatings was enhanced by successively pretreatment of PET by polyetherimide and polyacrylic acid and crosslinking. Measurements of water contact angle and atomic force microscope revealed that the coatings created a highly hydrophilic surface with low roughness. Adherences of Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) on PET with CHI/PVP coating were significantly reduced. Bactericidal activity of CHI/PVP coatings was good against E. coli and S. aureus and the adding of PVP obviously increased its antiadhesion property. In vitro cytotoxicity tests, cell morphology and activity evaluation of human umbilical vein endothelial cells showed that CHI/PVP coatings had good biocompatibility.

  2. Structural and optical characteristics of silver/poly(N-vinyl-2-pyrrolidone) nanosystems synthesized by γ-irradiation

    NASA Astrophysics Data System (ADS)

    Jovanović, Željka; Radosavljević, Aleksandra; Šiljegović, Milorad; Bibić, Nataša; Mišković-Stanković, Vesna; Kačarević-Popović, Zorica

    2012-11-01

    Silver nanoparticles (AgNPs) were synthesized in situ by γ-irradiation using poly(N-vinyl-2-pyrrolidone) (PVP) as a capping agent. The concentration, molecular weight and the structure (crosslinked and interpenetrated network) of PVP were varied, in order to determine the influence of the capping agent in the radiolytic synthesis of the Ag/PVP nanosystems. Transmission electron microscopy (TEM) showed that AgNPs obtained from the solutions containing higher PVP concentration and higher molecular weight were spherical in shape, with narrow size distribution and a diameter of˜6 nm, while slightly larger rod-shaped silver agglomerates, with bimodal nanoparticle size distribution and diameters of ˜10 nm and ˜20 nm were obtained from the solutions containing lower PVP concentration and lower molecular weight. Strong plasmon coupling and extending of plasmon resonance was observed by UV-vis spectroscopy, as a result of formation of nanorod-like agglomerates. Crosslinked and interpenetrated network did not affect the structure of synthesized AgNPs. Ag/PVP nanocomposite, in the form of thin film, was obtained by solvent evaporation from Ag/PVP colloid solution with 10 wt% of PVP, and characterized by FTIR spectroscopy. The interactions in Ag/PVP nanocomposite are shown to be the result of the coordination bonding between AgNPs and nitrogen from pyrrolidone ring of PVP. The optical properties of investigated Ag/PVP nanosystems, as measured by the values of optical band gap, Eg, are mainly the consequence of the interparticle distance as a result of the concentration and the structure of surrounding PVP macromolecules.

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

    PubMed

    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. PMID:24901895

  4. Prostatosymphyseal Fistula Treated by Robotic Assisted Radical Prostatectomy

    PubMed Central

    Whelan, Lucy; Mullarkey, Emma; Woo, Henry H.

    2015-01-01

    This case report documents a rare complication of prostate resection following a Greenlight laser procedure. The 75-year-old gentleman involved underwent photoselective vaporisation of the prostate (PVP) for clinically benign prostatic obstruction. Subsequent to PVP, the patient experienced recurrent macroscopic haematuria and pubic pain. Investigations confirmed the presence of a prostate-symphyseal fistula, a rare complication of PVP. We believe this to be the first reported case of successful treatment with robotic assisted radical prostatectomy. PMID:26576316

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

    PubMed

    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. PMID:25736374

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

    PubMed Central

    Uppalapati, Suji; Kong, Na; Norberg, Oscar; Ramström, Olof; Yan, Mingdi

    2015-01-01

    Covalently immobilized poly(4-vinylphenol) (PVP) monolayer films were fabricated by spin coating PVP on perfluorophenyl azide (PFPA)-functionalized surface 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 pKa value of these covalently immobilized PVP monolayers, 13.4 by SPR, was 3 units higher than that of the free polymer in aqueous solution. PMID:26097271

  7. Influence of solvent evaporation rate and formulation factors on solid dispersion physical stability.

    PubMed

    Wu, Jian X; Yang, Mingshi; Berg, Frans van den; Pajander, Jari; Rades, Thomas; Rantanen, Jukka

    2011-12-18

    New chemical entities (NCEs) often show poor water solubility necessitating solid dispersion formulation. The aim of the current study is to employ design of experiments in investigating the influence of one critical process factor (solvent evaporation rate) and two formulation factors (PVP:piroxicam ratio (PVP:PRX) and PVP molecular weight (P(MW))) on the physical stability of PRX solid dispersion prepared by the solvent evaporation method. The results showed the rank order of an increase in factors contributing to a decrease in the extent of PRX nucleation being evaporation rate>PVP:PRX>P(MW). The same rank order was found for the decrease in the extent of PRX crystal growth in PVP matrices from day 0 up to day 12. However, after 12days the rank became PVP:PRX>evaporation rate>P(MW). The effects of an increase in evaporation rate and PVP:PRX ratio in stabilizing PRX were of the same order of magnitude, while the effect from P(MW) was much smaller. The findings were confirmed by XRPD. FT-IR showed that PRX recrystallization in the PVP matrix followed Ostwald's step rule, and an increase in the three factors all led to increased hydrogen bonding interaction between PRX and PVP. The present study showed the applicability of the Quality by Design approach in solid dispersion research, and highlights the need for multifactorial analysis. PMID:22024381

  8. Delivery of fullerene-containing complexes via microgel swelling and shear-induced release.

    PubMed

    Tarabukina, Elena; Zoolshoev, Zoolsho; Melenevskaya, Elena; Budtova, Tatiana

    2010-01-15

    The absorption and release of poly(vinylpyrrolidone)-fullerene C60 complexes (PVP/C60) from a model microgel is studied. A dry microgel based on a chemically cross-linked sodium polyacrylate was swollen in the aqueous solutions of complexes which were afterwards released under shear stress. First, gel swelling degree in static conditions in the excess of PVP/C60 solutions was studied: the degree of swelling decreases with the increase in PVP/C60 concentration. While pure PVP is homogeneously distributed between the gel and the surrounding solution, a slight concentration of complexes outside the gel was recorded. It was attributed to PVP/C60 hydrophobicity leading to the decrease in the thermodynamic quality of fullerene-containing solution being gel solvent. The release of PVP/C60 solutions induced by shear was studied with counter-rotating rheo-optical technique and compared with PVP solution release under the same conditions. The amount of solution released depends on polymer concentration and shear strain. Contrary to pure PVP solutions in which rate of release decreases with the increase in polymer concentration, PVP/C60 complexes are released faster when fullerene concentration inside the gel is higher. PMID:19766708

  9. Photovoltaic water pumps, an attractive tool for rural drinking water supply

    SciTech Connect

    Posorski, R.

    1996-10-01

    Photovoltaic water pumps (PVP) are an attractive tool for a rural drinking water supply. An international field testing programme verified the technical maturity of PVP and their reliable field operation. Within well defined site selection criteria, the PVP are competitive with or the least-cost option for replacing small diesel-driven pumps. Introduced to the users through an appropriate community participation concept, the PVP achieved a high level of acceptance by the users, as evidenced by their willingness to pay for the consumed water. 10 refs., 6 figs.

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

    SciTech Connect

    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 (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.

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

    PubMed

    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. PMID:26249617

  12. Removal of polyvinylpyrrolidone from wastewater using different methods.

    PubMed

    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

  13. Low dielectric constant-based organic field-effect transistors and metal-insulator-semiconductor capacitors

    NASA Astrophysics Data System (ADS)

    Ukah, Ndubuisi Benjamin

    This thesis describes a study of PFB and pentacene-based organic field-effect transistors (OFET) and metal-insulator-semiconductor (MIS) capacitors with low dielectric constant (k) poly(methyl methacrylate) (PMMA), poly(4-vinyl phenol) (PVP) and cross-linked PVP (c-PVP) gate dielectrics. A physical method -- matrix assisted pulsed laser evaporation (MAPLE) -- of fabricating all-polymer field-effect transistors and MIS capacitors that circumvents inherent polymer dissolution and solvent-selectivity problems, is demonstrated. Pentacene-based OFETs incorporating PMMA and PVP gate dielectrics usually have high operating voltages related to the thickness of the dielectric layer. Reduced PMMA layer thickness (≤ 70 nm) was obtained by dissolving the PMMA in propylene carbonate (PC). The resulting pentacene-based transistors exhibited very low operating voltage (below -3 V), minimal hysteresis in their transfer characteristics, and decent electrical performance. Also low voltage (within -2 V) operation using thin (≤ 80 nm) low-k and hydrophilic PVP and c-PVP dielectric layers obtained via dissolution in high dipole moment and high-k solvents -- PC and dimethyl sulfoxide (DMSO), is demonstrated to be a robust means of achieving improved electrical characteristics and high operational stability in OFETs incorporating PVP and c-PVP dielectrics.

  14. Size-dependent toxicity of silver nanoparticles to Glyptotendipes tokunagai

    PubMed Central

    Choi, Seona; Kim, Soyoun; Bae, Yeon-Jae; Park, June-Woo; Jung, Jinho

    2015-01-01

    Objectives This study aims to evaluate the size-dependent toxicity of spherical silver nanoparticles (Ag NPs) to an endemic benthic organism, Glyptotendipes tokunagai. Methods Ag nanoparticles of three nominal sizes (50, 100, and 150 nm) capped with polyvinyl pyrrolidone (PVP-Ag NPs) were used. Their physicochemical properties, acute toxicity (48 hours), and bioaccumulation were measured using third instar larvae of G. tokunagai. Results The aggregation and dissolution of PVP-Ag NPs increased with exposure time and concentration, respectively, particularly for 50 nm PVP-Ag NPs. However, the dissolved concentration of Ag ions was not significant compared with the median lethal concentration value for AgNO3 (3.51 mg/L). The acute toxicity of PVP-Ag NPs was highest for the smallest particles (50 nm), whereas bioaccumulation was greatest for the largest particles (150 nm). However, larger PVP-Ag NPs were absorbed and excreted rapidly, resulting in shorter stays in G. tokunagai than the smaller ones. Conclusions The size of PVP-Ag NPs significantly affects their acute toxicity to G. tokunagai. In particular, smaller PVP-Ag NPs have a higher solubility and stay longer in the body of G. tokunagai, resulting in higher toxicity than larger PVP-Ag NPs. PMID:26184045

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

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

    EPA Science Inventory

    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...

  17. A facile soft template synthesis and characterization of PbHAsO{sub 4} nanocrystals

    SciTech Connect

    Xiu Zhiliang; Lue Mengkai . E-mail: mklu@icm.sdu.edu.cn; Zhou Guangjun; Gu Feng; Zhang Haiping; Xu Dong; Yuan Duorong

    2004-11-02

    Monoclinic lead hydrogen arsenate (LHA) nanocrystals with different crystallization morphologies and crystallite sizes were prepared successfully by a soft template synthesis method in the presence of sodium dodecylbenzenesulfonate (SDBS) or polyvinylpyrrolidone (PVP). The products were characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The possible mechanism of SDBS and PVP in the experiment was briefly illustrated.

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

    EPA Science Inventory

    The toxicity, bioaccumulation and biotransformation of citrate and polyvinylpyrrolidone (PVP) coated silver nanoparticles (NPs) (AgNP-citrate and AgNP-PVP) in marine organisms via marine sediment exposure was investigated. Results from 7-d sediment toxicity tests indicate that Ag...

  19. Blends and Iodine complexes of starch with other water-soluble polymers

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In this work, we studied the viscosity and gel formation in the tri-component system, starch/poly(acrylic acid) (PAA), poly(N-vinyl pyrrolidone) (PVP). Starch and poly(acrylic acid) at 5% aqueous solution formed a synergistic mixture at 60/40 ratio. The addition of a small amount of PVP caused the...

  20. Interference of Cerebrospinal Fluid Total Protein Measurement by Povidone-Iodine Contamination

    PubMed Central

    Gounden, Verena; Sacks, David B; Zhao, Zhen

    2014-01-01

    Background A falsely high cerebrospinal fluid (CSF) total protein (TP) result measured by pyrogallol red (PGR) method was suspected to be caused by preparation of the collection site with povidone-iodine (PVP-iodine) solution. Methods CSF TP was evaluated for interference in samples with different final concentrations of PVP-iodine (up to 0.25% PVP and 0.025% iodine) or iodine alone (up to 0.025% iodine) using three methods: PGR, modified biuret and benzethonium chloride (BZTC). Interference exceeding ±20% of the baseline value is considered clinically significant according the criterion defined by College of American Pathologists. Results There was a positive interference with the PGR method and a negative inference for the BZTC method in CSF samples spiked with PVP-iodine. The PVP-iodine (up to 0.25% PVP and 0.025% iodine) did not cause a clinically significant interference with the modified biuret method. PVP alone without iodine caused a positive interference with the PGR method but did not interfere with the modified biuret or the BZTC method. When the samples were spiked with iodine alone, none of the three methods was affected (change < 20%) by iodine concentration up to 0.025%. Conclusions Contamination of CSF specimens with PVP-iodine can lead to interference with CSF TP measurements using PGR or BZTC methods. PMID:25446880

  1. High-yield halide-free synthesis of biocompatible Au nanoplates.

    PubMed

    Wang, Guoqing; Tao, Shengyang; Liu, Yiding; Guo, Lei; Qin, Guohui; Ijiro, Kuniharu; Maeda, Mizuo; Yin, Yadong

    2016-01-01

    We communicate an unconventional synthesis of Au nanoplates with high yield and excellent reproducibility through polyvinylpyrrolidone (PVP)-assisted H2O2 reduction. Unlike the ones prepared using halide-based surfactants, the PVP-capped Au nanoplates are found to afford fairly easy bio-functionalization, suggesting a vastly expanded spectrum of applications in bio-related fields. PMID:26524080

  2. GC-MS analysis of the designer drug α-pyrrolidinovalerophenone and its metabolites in urine and blood in an acute poisoning case.

    PubMed

    Grapp, Marcel; Sauer, Christoph; Vidal, Christian; Müller, Dieter

    2016-02-01

    α-Pyrrolidinovalerophenone (α-PVP) is a synthetic cathinone belonging to the group of "second generation" pyrrolidinophenones that becomes more and more popular as a designer psychostimulant. Here we provide toxicological analytical support for a severe poisoning with α-PVP. Serum and urine samples that were sent to our laboratory were subjected to a general unknown screening procedure. The procedure includes immunoassay-based screening of drugs of abuse in serum and systematic toxicological analysis of urine and serum after neutral and basic liquid-liquid extraction followed by gas chromatography-mass spectrometry (GC-MS). Whereas the immunoassay delivered negative results, analyzing the urine sample by GC-MS in full scan mode disclosed the presence of α-PVP and its metabolites α-(2″-oxo-pyrrolidino)valerophenone (2″-oxo-α-PVP) and 1-phenyl-2-(pyrrolidin-1-yl)pentan-1-ol (OH-α-PVP). In the acetylated urine sample we found additionally N,N-bis-dealkyl-PVP. In serum, α-PVP could be detected after solid phase extraction and a concentration of 29ng/mL was determined. Other forensic relevant substances were not detected. The presented data can explain the psychotic symptoms and behavioural pattern of the subject after abuse of α-PVP, leading to a clinical condition similar to excited delirium syndrome. PMID:26775198

  3. Preparation of an oral acetaminophen film that is expected to improve medication administration: Effect of polyvinylpyrrolidone on physical properties of the film.

    PubMed

    Ito, Ikumi; Ito, Akihiko; Unezaki, Sakae

    2016-01-01

    This study investigated the effect of polyvinylpyrrolidone (PVP) on a film containing carboxymethyl cellulose sodium (CMC) as a matrix to improve surface roughness caused by drug recrystallization. Acetaminophen (AA) was used as the model drug. Recrystallization is a problem encountered during the preparation of films that contain high drug doses, making them difficult to take. A film that does not disintegrate for clinical applications requires a smooth surface, moderate strength and elasticity, and a low level of adhesiveness to facilitate taking of the medication. Addition of PVP to the film formulation made the surface significantly smoother, and it was independent of the compounding method. Smooth films were obtained when the CMC concentration was kept constant and the amount of PVP was increased, but it also increased the adhesiveness and strength, and decreased the elasticity of the films. When high polymer concentration was kept constant and the ratio of CMC and PVP was varied, the films with smaller amounts of PVP tended to have a smoother surface and less adhesiveness. However, when the amount of PVP was reduced, the film strength increased and elasticity decreased. The amount of PVP had a negligible effect on drug dissolution behavior, making it useful for preparation of the AA film. However, it is necessary to determine the compounding method and the PVP load considering the adhesiveness, strength, and elasticity of the films. PMID:27301710

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

    NASA Astrophysics Data System (ADS)

    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%.

  5. Poly(N-vinylpyrrolidone)-modified poly(dimethylsiloxane) elastomers as anti-biofouling materials.

    PubMed

    Wu, Zhaoqiang; Tong, Weifang; Jiang, Wenwen; Liu, Xiaoli; Wang, Yanwei; Chen, Hong

    2012-08-01

    A new method for the modification of poly(dimethylsiloxane) (PDMS) elastomer surfaces with hydrophilic poly(N-vinylpyrrolidone) (PVP) has been developed. PVP chains were grafted from the PDMS surface by surface-initiated atom transfer radical polymerization (SI-ATRP). The resulting surfaces were characterized by X-ray photoelectron spectroscopy (XPS), attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), atomic force microscopy (AFM) and water contact angle measurements. It was shown that the modified surfaces were strongly hydrophilic, indicating that the PVP grafts dominate the surface and define its properties. The anti-fouling properties of the grafted surfaces were demonstrated in protein adsorption and cell adhesion experiments. Both protein adsorption and cell adhesion were inhibited significantly on the PVP-modified PDMS surfaces compared to unmodified controls. It is concluded that modification by SI-ATRP grafting of PVP is an effective method for the preparation of anti-biofouling PDMS materials. PMID:22510455

  6. Fabrication of Pt nanoparticle incorporated polymer nanowires by high energy ion and electron beam irradiation

    NASA Astrophysics Data System (ADS)

    Tsukuda, Satoshi; Takahasi, Ryouta; Seki, Shu; Sugimoto, Masaki; Idesaki, Akira; Yoshikawa, Masahito; Tanaka, Shun-Ichiro

    2016-01-01

    Polyvinylpyrrolidone (PVP)-Pt nanoparticles (NPs) hybrid nanowires were fabricated by high energy ion beam irradiation to PVP thin films including H2PtCl6. Single ion hitting caused crosslinking reactions of PVP and reduction of Pt ions within local cylindrical area along an ion trajectory (ion track); therefore, the PVP nanowires including Pt NPs were formed and isolated on Si substrate after wet-development procedure. The number of Pt NPs was easily controlled by the mixed ratio of PVP and H2PtCl6. However, increasing the amount of H2PtCl6 led to decreasing the radial size and separation of the hybrid nanowires during the wet-development. Additional electron beam irradiation after ion beam improved separation of the nanowires and controlled radial sizes due to an increase in the density of crosslinking points inner the nanowires.

  7. A novel phosphoric acid doped poly(ethersulphone)-poly(vinyl pyrrolidone) blend membrane for high-temperature proton exchange membrane fuel cells

    NASA Astrophysics Data System (ADS)

    Xu, Xin; Wang, Haining; Lu, Shanfu; Guo, Zhibin; Rao, Siyuan; Xiu, Ruijie; Xiang, Yan

    2015-07-01

    A high-temperature proton exchange membrane, poly(ethersulphone)-poly(vinyl pyrrolidone) (PES-PVP) blend membrane is successfully prepared by scalable polymer blending method. The physical properties of blend membrane are characterized by DSC, TG and tensile strength test. The DSC and TG results indicate PES-PVP blend membranes possess excellent thermal stability. After phosphoric acid (PA) doping treatment, the blend membrane shows enhanced proton conductivity. PA doping level and volume swelling ratio of the blend membrane are found to be positively related to the PVP content. A high proton conductivity of 0.21 S/cm is achieved at 180 °C for PA doped PES-PVP 80% with a PA doping level of 9.1. PEM fuel cell based on PA doped PES-PVP 80% membrane shows a high power density of 850 mW/cm2 and outstanding stability at 180 °C without extra humidification.

  8. Regulation of the reaction of N-polyvinylpyrrolidone with iodine

    SciTech Connect

    Trubitsyna, S.N.

    1985-09-01

    The route chosen for modification of the sorption capacity of N -polyvinylpyrrolidone (PVP) was stabilization of its polymer skeleton by the action of intermolecular hydrogen bonds. The secondary supermolecular formations were regulated by introduction into aqueous solution polyvinylpyrrolidone at room temperature of substances containing active groups tending to form intermolecular H bonds with electron donors-oxygen atoms of carbonyl groups in PVP. Figures show IR absorption spectra of aqueous solutions of PVP, and dependence of the conductivity of aqueous solutions. It was concluded that preliminary addition both of monomeric and polymeric compounds, causing fromation of H bonds in the system, to PVP solutions causes significant changes in the structural organization of the PVP macromolecular chains, as the result of which the polymer acquires high sorption capacity for iodine.

  9. Synthesis and characterization of silver/poly( N-vinyl-2-pyrrolidone) hydrogel nanocomposite obtained by in situ radiolytic method

    NASA Astrophysics Data System (ADS)

    Jovanović, Željka; Krklješ, Aleksandra; Stojkovska, Jasmina; Tomić, Simonida; Obradović, Bojana; Mišković-Stanković, Vesna; Kačarević-Popović, Zorica

    2011-11-01

    This work describes radiolytic synthesis of silver nanoparticles (Ag NPs) within the poly( N-vinyl-2-pyrrolidone) (PVP) hydrogel. The hydrogel matrix was obtained by gamma irradiation-induced crosslinking, while the in situ reduction of Ag + ions was performed using strong reducing species formed under water radiolysis. Absorption spectrum of the Ag/PVP nanocomposite confirmed the formation of Ag NPs, showing the surface plasmon band maxima at 405 nm. Ag/PVP nanocomposites were characterized by XRD and TEM analysis, accompanied with investigations of swelling and diffusion properties in the simulated body fluid at 37 °C, and mechanical properties in bioreactor conditions. It was shown that Ag/PVP nanocomposite exhibited higher values of equilibrium swelling degree, Young's modulus, and molar mass between crosslinks, while lower values of the diffusion coefficient and effective crosslink density were obtained, as compared to the pure PVP.

  10. A survey of parametrized variational principles and applications to computational mechanics

    NASA Technical Reports Server (NTRS)

    Felippa, Carlos A.

    1993-01-01

    This survey paper describes recent developments in the area of parametrized variational principles (PVP's) and selected applications to finite-element computational mechanics. A PVP is a variational principle containing free parameters that have no effect on the Euler-Lagrange equations. The theory of single-field PVP's based on gauge functions (also known as null Lagrangians) is a subset of the inverse problem of variational calculus that has limited value. On the other hand, multifield PVP's are more interesting from theoretical and practical standpoints. Following a tutorial introduction, the paper describes the recent construction of multifield PVP's in several areas of elasticity and electromagnetics. It then discusses three applications to finite-element computational mechanics: the derivation of high-performance finite elements, the development of element-level error indicators, and the constructions of finite element templates. The paper concludes with an overview of open research areas.

  11. Polyvinylpyrrolidone-sodium dodecylsulfate complex is a family of pseudo-polyanions with different charge densities: Evidence from capillary electrophoresis, capillary viscosimetry and conductometry.

    PubMed

    Wu, Yefan; Chen, Jie; Fang, Yun; Zhu, Meng

    2016-10-01

    Accordance with the previously supposed polyelectrolyte-like behaviour of neutral polymer-anionic surfactant complexes, direct evidence for the formation of the pseudo-polyanions in polyvinylpyrrolidone (PVP)-sodium dodecylsulfate (SDS) solution is put forward in this paper by capillary electrophoresis (CE) experiments in assistance with capillary viscosimetry and conductometry. The contradictory phenomena of the absolute value of relative electrophoretic mobility (re) increasing while the ionization degree (α) decreasing with the increasing specific clusterization [Г] in aqueous PVP-SDS solution are explained by the finding that the PVP-SDS complex is eventually a family of PVP-SDS pseudo-polyanions with different charge densities. And it is found countercations playing an important role in the formation of the PVP-SDS pseudo-polyanions in virtue of bridge effect. PMID:27348481

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

    PubMed

    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. PMID:9850746

  13. Li2S cathode modified with polyvinylpyrrolidone and mechanical milling with carbon

    NASA Astrophysics Data System (ADS)

    Liu, Jun; Nara, Hiroki; Yokoshima, Tokihiko; Momma, Toshiyuki; Osaka, Tetsuya

    2015-01-01

    Polyvinylpyrrolidone (PVP) is used with polyethylene oxide (PEO) as a mixed binder for mechanically milled Li2S. PVP demonstrates its advantage in terms of increasing the capacity of Li2S, but boosts the potential barrier at the beginning of the first charge. It is also revealed that PVP retards the charge-transfer kinetics of Li2S. In Li2S-C prepared by mechanical milling, carbon compensates for the electrochemical insulation of the PVP binder and improves the cycle stability. As a result, the Li2S-C-PVP electrode with 60 wt% Li2S content displays a low potential barrier at the onset of charge and a stable capacity of about 460 mAh g-1 at 0.1 C.

  14. Synthesis of PbS/poly (vinyl-pyrrolidone) nanocomposite

    SciTech Connect

    Patel, Jayesh D.; Chaudhuri, Tapas K.

    2009-08-05

    A simple solution growth method for synthesis of nanocomposite of PbS nanoparticles in poly(vinyl-pyrrolidone) (PVP) polymer is described. The nanocomposite is prepared from methanolic solution of lead acetate (PbAc), thiourea (TU) and PVP at room temperature ({approx}27 deg. C). Optical absorption spectrum of PbS/PVP nanocomposite solution shows strong absorption from 300 to 650 nm with significant bands at 400 and 590 nm which is characteristic of nanoscale PbS. Spin-coated nanocomposite films on glass have an absorption edge at {approx}650 nm with band gap of 2.55 eV. Fourier transform infrared (FTIR) spectroscopy of PbS/PVP nanocomposite and PVP shows strong chemical bond between PbS nanoparticles and host PVP polymer. The transmission electron microscope (TEM) images reveal that 5-10 nm PbS particles are evenly embedded in PVP polymer. The formation of PbS is confirmed by selective area electron diffraction (SAED) of a typical nanoparticle.

  15. Nanocomposite scaffold with enhanced stability by hydrogen bonds between collagen, polyvinyl pyrrolidone and titanium dioxide.

    PubMed

    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. PMID:26764111

  16. Influence of polymer content on stabilizing milled amorphous salbutamol sulphate.

    PubMed

    Balani, P N; Wong, S Y; Ng, W K; Widjaja, E; Tan, R B H; Chan, S Y

    2010-05-31

    The study investigates the influence of polyvinyl pyrrolidone (PVP) concentration on stabilizing the amorphous form of salbutamol sulphate (SS) before and after storage under ambient and elevated humidity conditions. Different mass ratios of SS and PVP (0-90wt%) were co-milled using a planetary ball mill. X-ray powder diffraction (XRPD), high sensitivity differential scanning calorimetry (HSDSC), dynamic vapor sorption (DVS), infrared spectroscopy (FT-IR), scanning electron microscopy (SEM) and Raman microscopy (RM) were used to analyze the stability of the co-milled mixtures against heat and humidity treatments as well as storage at different humidity conditions. Prior storage, DSC and DVS analyses revealed that re-crystallization of amorphous SS was suppressed above PVP content of 33 wt%. Probable hydrogen bond interaction between SS and PVP was found in FT-IR analysis. XRPD diffractograms and SEM analysis showed stability against re-crystallization was achieved in the co-milled mixtures with a minimum PVP content of 80 wt% after storage. Homogeneous distribution of SS and PVP from RM analysis showed fine clustering of SS and PVP, suggesting the formation of an amorphous dispersion at molecular level. The results provide insights on the application of thermal and humidity treatments, accelerated stability testing and investigations on drug-excipient interactions to predict the minimum ratio of an excipient for stabilizing the amorphous state of a milled API. PMID:20211717

  17. Aligned Electrospun Polyvinyl Pyrrolidone/Poly ɛ-Caprolactone Blend Nanofiber Mats for Tissue Engineering

    NASA Astrophysics Data System (ADS)

    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.

  18. Safety and Efficacy Studies of Vertebroplasty, Kyphoplasty, and Mesh-Container-Plasty for the Treatment of Vertebral Compression Fractures: Preliminary Report.

    PubMed

    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

  19. Inductive effect of poly(vinyl pyrrolidone) on morphology and photocatalytic performance of Bi2WO6

    NASA Astrophysics Data System (ADS)

    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.

  20. Influence of Sterilization and Storage Period on Elution of Polyvinylpyrrolidone from Wet-Type Polysulfone Membrane Dialyzers.

    PubMed

    Miyata, Masahiro; Konishi, Shuji; Shimamoto, Yoshimasa; Kamada, Aki; Umimoto, Koichi

    2015-01-01

    The objectives of this study were to investigate the influence of the sterilization and storage period on elution of polyvinylpyrrolidone (PVP) from wet-type polysulfone (PSu) membrane dialyzers. APS-15SA (APS) dialyzers sterilized by gamma-radiation and RENAK PS-1.6 (RENAK) dialyzers sterilized by autoclaving were compared in this study. Each dialyzer was washed with physiological saline and the amount of PVP eluted from the PSu membrane was measured. Then, experimental use of each dialyzer was performed by circulating physiological saline for 4 hours, after which the PVP eluted from the PSu membrane was measured. As the results, the amount of PVP eluted by washing was positively correlated with the storage period for both dialyzers (APS: rs = 0.958; RENAK: rs = 0.952). In the experimental circuit, the amount of PVP eluted from the RENAK dialyzer was positively correlated with the storage period (rs = 0.810), whereas the amount of PVP eluted from the APS dialyzer was negatively correlated with the storage period (rs = -0.833). We found that the amount of PVP eluted from PSu membrane is quite different by the sterilization and storage period of dialyzers. PMID:25851313

  1. Safety and Efficacy Studies of Vertebroplasty, Kyphoplasty, and Mesh-Container-Plasty for the Treatment of Vertebral Compression Fractures: Preliminary Report

    PubMed Central

    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

  2. Evaluation of a poly(vinyl pyrollidone)-coated biomaterial for urological use.

    PubMed

    Tunney, M M; Gorman, S P

    2002-12-01

    The associated problems of bacterial biofilm formation and encrustation that may cause obstruction or blockage of urethral catheters and ureteral stents often hinders the effective use of biomaterials within the urinary tract. In this in vitro study, we have investigated the surface properties of a hydrophilic poly(vinyl pyrollidone) (PVP)-coating applied to polyurethane and determined its suitability for use as a urinary tract biomaterial by comparing its lubricity and ability to resist bacterial adherence and encrustation with that of uncoated polyurethane and silicone. The PVP-coated polyurethane was significantly more hydrophilic and more lubricious than either uncoated polyurethane or silicone. Adherence of a hydrophilic Escherichia coli isolate to PVP-coated polyurethane and uncoated polyurethane was similar but significantly less than adherence to silicone. Adherence of a hydrophobic Enterococcus faecalis isolate to PVP-coated polyurethane and silicone was similar but was significantly less than adherence to uncoated polyurethane. Struvite encrustation was similar on the PVP-coated polyurethane and silicone but significantly less than on uncoated polyurethane. Furthermore, hydroxyapatite encrustation was significantly less on the PVP-coated polyurethane than on either uncoated polyurethane or silicone. The results suggest that the PVP-coating could be useful in preventing complications caused by bacterial biofilm formation and the deposition of encrustation on biomaterials implanted in the urinary tract and, therefore, warrants further evaluation. PMID:12322981

  3. Rheological behaviour of irradiated wound dressing poly(vinyl pyrrolidone) hydrogels

    NASA Astrophysics Data System (ADS)

    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.

  4. Effects of polyvinylpyrrolidone both as a binder and pore-former on the release of sparingly water-soluble topiramate from ethylcellulose coated pellets.

    PubMed

    Yang, Meiyan; Xie, Si; Li, Qiu; Wang, Yuli; Chang, Xinyi; Shan, Li; Sun, Lei; Huang, Xiaoli; Gao, Chunsheng

    2014-04-25

    Delivering sparingly water-soluble drugs from ethylcellulose (EC) coated pellets with a controlled-release pattern remains challenging. In the present study, hydrophilic polyvinylpyrrolidone (PVP) was used both as a binder and a pore-former in EC coated pellets to deliver sparingly water-soluble topiramate, and the key factors that influenced drug release were identified. When the binder PVP content in drug layers below 20% w/w was decreased, the physical state of topiramate changed from amorphous to crystalline, making much difference to drug solubility and dissolution rates while modifying the drug release profile from first-order to zero-order. In addition, without PVP in drug layering solution, drug layered particles were less sticky during layering process, thus leading to a shorter process and higher loading efficiency. Furthermore, PVP level as a pore-former in EC coating layers mainly governed drug release from the coated pellets with the sensitivity ranging from 23% to 29%. PVP leaching rate and water permeability from EC/PVP film increased with the PVP level, which was perfectly correlated with drug release rate. Additionally, drug release from this formulation was independent of pH of release media or of the paddle mixing speed, but inversely proportional to the osmolality of release media above the physiological range. PMID:24530810

  5. Inactivation of human viruses by povidone-iodine in comparison with other antiseptics.

    PubMed

    Kawana, R; Kitamura, T; Nakagomi, O; Matsumoto, I; Arita, M; Yoshihara, N; Yanagi, K; Yamada, A; Morita, O; Yoshida, Y; Furuya, Y; Chiba, S

    1997-01-01

    Inactivation of a range of viruses, such as adeno-, mumps, rota-, polio- (types 1 and 3), coxsackie-, rhino-, herpes simplex, rubella, measles, influenza and human immunodeficiency viruses, by povidone-iodine (PVP-I) and other commercially available antiseptics in Japan was studied in accordance with the standardized protocol in vitro. In these experiments, antiseptics such as PVP-I solution, PVP-I gargle, PVP-I cream, chlorhexidine gluconate, alkyldiaminoethyl-glycine hydrochloride, benzalkonium chloride (BAC) and benzethonium chloride (BEC) were used. PVP-I was effective against all the virus species tested. PVP-I drug products, which were examined in these experiments, inactivated all the viruses within a short period of time. Rubella, measles, mumps viruses and HIV were sensitive to all of the antiseptics, and rotavirus was inactivated by BAC and BEC, while adeno-, polio- and rhinoviruses did not respond to the other antiseptics. PVP-I had a wider virucidal spectrum, covering both enveloped and nonenveloped viruses, than the other commercially available antiseptics. PMID:9403252

  6. Combined gene therapy of endostatin and interleukin 12 with polyvinylpyrrolidone induces a potent antitumor effect on hepatoma

    PubMed Central

    Li, Pei-Yuan; Lin, Ju-Sheng; Feng, Zuo-Hua; He, Yu-Fei; Zhou, He-Jun; Ma, Xin; Cai, Xiao-Kun; Tian, De-An

    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 muscle 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. PMID:15259064

  7. A Systematic Review and Meta-Analysis of Functional Outcomes and Complications Following the Photoselective Vaporization of the Prostate and Monopolar Transurethral Resection of the Prostate

    PubMed Central

    Kang, Dong Hyuk; Cho, Kang Su; Ham, Won Sik; Choi, Young Deuk

    2016-01-01

    Purpose To perform a systematic review and meta-analysis of randomized controlled trials (RCTs) comparing monopolar transurethral resection of the prostate (MTURP) and photoselective vaporization of the prostate (PVP) in order to provide the most up-to-date and reliable recommendations possible. Materials and Methods Relevant RCTs were identified from electronic databases for meta-analysis of the surgical outcomes and complications of MTURP and PVP. Meta-analytical comparisons were made using qualitative and quantitative syntheses. The outcome variables are presented as odds ratios with 95% confidence intervals (CIs). Results In total, 11 articles were included in this comparative analysis of PVP versus MTURP. Most of the recently published studies exhibited low risk in terms of quality assessment. MTURP was superior to PVP regarding operative time; however, with regard to catheterization and hospitalization time, the mean differences were -1.39 (95% CI=-1.83~-0.95, p<0.001) and -2.21 (95% CI=-2.73~-1.69, p<0.001), respectively, in favor of PVP. PVP was superior to MTURP with regard to transfusion rate and clot retention, but no statistically significant differences were found with regard to acute urinary retention and urinary tract infection. The long-term complications of bladder neck contracture and urethral stricture showed no statistically significant differences between PVP and MTURP. Long-term functional outcomes, including the International Prostate Symptom Score and maximum flow rate, likewise did not display statistically significant differences between PVP and MTURP. Conclusions Based on our findings, we believe that PVP should be considered as an alternative surgical procedure for treating male lower urinary tract symptoms secondary to benign prostatic hyperplasia. PMID:27574594

  8. Anti-tack action of polyvinylpyrrolidone on hydroxypropylmethylcellulose solution.

    PubMed

    Chan, Lai Wah; Wong, Tin Wui; Chua, Pih Chng; York, Peter; Heng, Paul Wan Sia

    2003-02-01

    The anti-tack action of polyvinylpyrrolidone (PVP) on hydroxypropylmethylcellulose (HPMC) solution was elucidated using a probe test method. The influence of PVP of varying molecular weights at various PVP concentrations and solution temperatures on the tackiness of HPMC solution was studied. The viscosity, surface tension, cloud point and solution spectroscopy of HPMC solutions and glass transition temperature of HPMC films, with and without PVP, were investigated. The tackiness of HPMC solutions in response to the addition of PVP, at different concentrations of HPMC and using HPMC with varying contents of hydroxypropyl/methoxyl substitution, was also evaluated. PVP is a commonly used binder and adhesive. However, it reduced the tack of the HPMC solution when used at low concentrations, without affecting the state of hydration of HPMC. Lower molecular weight PVP was more effective as an anti-tack agent owing to suitable hydrodynamic size to intersperse among the HPMC chains. The degree of reduction in tack values was more pronounced for HPMC that showed a greater extent of interaction between polymer chains such as when high concentration of HPMC or low solution temperature was employed. This indicated that the tack reduction property of PVP relied on its ability to interact with the HPMC chains. The profile of reduction in tack values was affected by the contents of HPMC substitution and was a result of net reduction in the extent of hydrogen bonding between HPMC chains. It was significantly correlated to the changes of viscosity and surface tension of the HPMC solutions but not to the glass transition temperatures of the polymers prepared as solid films. The results suggested that the anti-tack action of PVP was attributed to its ability to interact with HPMC chains in the aqueous medium and consequently to reduce the extent of HPMC-HPMC bonding. PMID:12576641

  9. Radiological Follow-up of New Compression Fractures Following Percutaneous Vertebroplasty

    SciTech Connect

    Tanigawa, Noboru Komemushi, Atsushi; Kariya, Shuji; Kojima, Hiroyuki; Shomura, Yuzo; Sawada, Satoshi

    2006-02-15

    The purpose of the present study was to ascertain chronological changes in the analgesic effects of percutaneous vertebroplasty (PVP) on osteoporotic vertebral compression factures and to radiologically follow new compression fractures after PVP. Seventy-six patients (206 vertebral bodies) were followed radiologically for a mean of 11.5 months. A visual analog scale (VAS; 0-10) was used to assess pain severity, and frontal and lateral plain radiographs of the thoracic and lumbar vertebrae were taken 1-3 days and 1, 4, 10, and 22 months after PVP.The average VAS score was 7.2 {+-} 2.0 (mean pain score {+-} standard deviation) before PVP, 2.5 {+-} 2.3 at 1-3 days after PVP, 2.2 {+-} 2.3 at 1 month, 1.9 {+-} 2.2 at 4 months, 1.8 {+-} 2.4 at 10 months, and 1.0 {+-} 0.2 at 22 months. A new compression fracture was confirmed in 56 vertebral bodies in 28 patients (36.8%), affecting 38 adjacent vertebral bodies (67.8%), 17 nonadjacent vertebral bodies (30.4%), and 1 treated vertebral body (1.8%). A new compression fracture occurred within 1 week of PVP in 2 vertebral bodies (3.6%), between 1 week and 1 month after PVP in 22 (39.3%), between 1 and 3 months in 12 (21.4%), between 3 and 6 months in 12 (21.4%), and after more than 6 months in 8 (14.3%). PVP was highly effective in relieving the pain associated with osteoporosis-induced vertebral compression fractures, and this analgesia was long lasting. Radiological follow-up observation revealed new compression fractures in about one-third of patients. More than half of these new compression fractures occurred in adjacent vertebral bodies within 3 months of PVP.

  10. The polyvinylpyrrolidone functionalized rGO/Bi2S3 nanocomposite as a near-infrared light-responsive nanovehicle for chemo-photothermal therapy of cancer.

    PubMed

    Dou, Ruixia; Du, Zhen; Bao, Tao; Dong, Xinghua; Zheng, Xiaopeng; Yu, Miao; Yin, Wenyan; Dong, Binbin; Yan, Liang; Gu, Zhanjun

    2016-06-01

    Recently, a combination of chemotherapy with photothermal therapy (PTT) has received great attention for the construction of a near infrared (NIR)-controlled drug-delivery system for synergistic treatment of cancer, ultimately resulting in the enhancement of the therapeutic efficacy of anticancer drugs. Here, we developed a novel system for synergistic cancer therapy based on bismuth sulfide (Bi2S3) nanoparticle-decorated graphene functionalized with polyvinylpyrrolidone (PVP) (named PVP-rGO/Bi2S3). The as-prepared PVP-rGO/Bi2S3 nanocomposite has a high storage capacity for anticancer drugs (∼500% for doxorubicin (DOX)) and simultaneously has perfect photothermal conversion efficiency in the NIR region. The results of the in vitro accumulative drug release test manifests that the PVP-rGO/Bi2S3 nanocomposite could be applied as a dual pH- and NIR-responsive nanotherapeutic carrier for the controlled release of DOX from DOX-loaded PVP-rGO/Bi2S3 (PVP-rGO/Bi2S3@DOX). Moreover, the treatment of both cancer cells (including Hela, MCF-7, HepG2 and BEL-7402 cells) and BEL-7402 tumor-bearing mice with the PVP-rGO/Bi2S3@DOX complex followed by NIR laser irradiation produces significantly greater inhibition of cancer cell growth than the treatment with NIR irradiation alone or DOX alone, exhibiting a synergistic antitumor effect. Furthermore, due to the obvious NIR and X-ray absorption ability, the PVP-rGO/Bi2S3 nanocomposite could be employed as a dual-modal contrast agent for both photoacoustic tomography and X-ray computed tomography imaging. In addition to the good biocompatibility, the PVP-rGO/Bi2S3 nanocomposite paves a potential way for the fabrication of theranostic agents for dual-modal imaging-guided chemo-photothermal combined cancer therapy. PMID:27203525

  11. Comparison of percutaneous vertebroplasty and percutaneous kyphoplasty for the management of Kümmell's disease: A retrospective study

    PubMed Central

    Zhang, Guang-Quan; Gao, Yan-Zheng; Chen, Shu-Lian; Ding, Shuai; Gao, Kun; Wang, Hong-Qiang

    2015-01-01

    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), and the improvement sustained at the final followup (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. PMID:26806962

  12. Antioxidation Properties and Surface Interactions of Polyvinylpyrrolidone-Capped Zerovalent Copper Nanoparticles Synthesized in Supercritical Water.

    PubMed

    Morioka, Takuya; Takesue, Masafumi; Hayashi, Hiromichi; Watanabe, Masaru; Smith, Richard L

    2016-01-27

    Zerovalent copper nanoparticles (CuNPs) (diameter, 26.5 ± 9 nm) capped with polyvinylpyrrolidone (PVP) were synthesized in supercritical water at 400 °C and 30 MPa with a continuous flow reactor. The PVP-capped CuNPs were dispersed in distilled water, methanol, ethanol, 1-propanol, 2-propanol, butanol, and their mixed solvents to study their long-term stability. Temporal variation of UV-vis spectra and surface plasmon resonance were measured and showed that ethanol, the propanols, and butanol solvents provided varying degrees of oxidative protection for Cu(0). Fourier transform infrared spectroscopy showed that PVP adsorbed onto the surface of the CuNPs with a pyrrolidone ring of PVP even if the CuNPs were oxidized. Intrinsic viscosities of PVP were higher for solvents that provided antioxidation protection than those that give oxidized CuNPs. In solvents that provided Cu(0) with good oxidative protection (ethanol, the propanols, and butanol), PVP polymer chains formed large radii of gyration and coil-like conformations in the solvents so that they were arranged uniformly and orderly on the surface of the CuNPs and could provide protection of the Cu(0) surface against dissolved oxygen. In solvents that provided poor oxidative protection for Cu(0) (water, alcohol-water mixed solvents with 30% water), PVP polymer chains had globular-like conformations due to their relatively high hydrogen-bonding interactions and sparse adsorption onto the CuNP surface. Antioxidative properties of PVP-capped CuNPs in a solvent can be ascribed to the conformation of PVP polymer chains on the Cu(0) particle surface that originates from the interaction between polymer chains and its interaction with the solvent. PMID:26716468

  13. Tageted bipolar radiofrequency decompression with vertebroplasty for intractable radicular pain due to spinal metastasis: a case report

    PubMed Central

    Baek, Seong Jin; Lee, Eun Young

    2016-01-01

    Metastatic spinal tumors are usually quite difficult to treat. In patients with metastatic spinal tumors, conventional radiotherapy fails to relieve pain in 20–30% of cases and open surgery often causes considerable trauma and complications, which delays treatment of the primary disease. Percutaneous vertebroplasty (PVP) is considered to be useful in achieving rapid pain control and preventing further vertebral collapse due to spinal metastasis. However, symptoms of intraspinal neural compression can be contraindications to PVP. To overcome this problem, we performed PVP following targeted bipolar radiofrequency decompression, and examined the effect of the combined treatment in relieving severe radicular pain related to spinal cord compression caused by malignant metastatic tumors. PMID:27482319

  14. Polyvinylpyrrolidone/Multiwall Carbon Nanotube Composite Based 36 deg. YX LiTaO{sub 3} Surface Acoustic Wave For Hydrogen Gas Sensing Applications

    SciTech Connect

    Chee, Pei Song; Arsat, Rashidah; He Xiuli; Arsat, Mahyuddin; Wlodarski, Wojtek; Kalantar-zadeh, Kourosh

    2011-05-25

    Poly-vinyl-pyrrolidone (PVP)/Multiwall Carbon Nanotubes (MWNTs) based Surface Acoustic Wave (SAW) sensors are fabricated and characterized, and their performances towards hydrogen gas are investigated. The PVP/MWNTs fibers composite are prepared by electrospinning of the composite aqueous solution deposited directly onto the active area of SAW transducers. Via scanning electron microscopy (SEM), the morphology of the deposited nanostructure material is observed. From the dynamic response, frequency shifts of 530 Hz (1%H{sub 2}) and 11.322 kHz (0.25%H{sub 2}) are recorded for the sensors contain of 1.525 g and 1.025 g PVP concentrations, respectively.

  15. Characteristic time scales of coalescence of silver nanocomposite and nanoparticle films induced by continuous wave laser irradiation

    SciTech Connect

    Paeng, Dongwoo; Grigoropoulos, Costas P.; Lee, Daeho

    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.

  16. Seeding atomic layer deposition of high-k dielectric on graphene with ultrathin poly(4-vinylphenol) layer for enhanced device performance and reliability

    NASA Astrophysics Data System (ADS)

    Cheol Shin, Woo; Yong Kim, Taek; Sul, Onejae; Jin Cho, Byung

    2012-07-01

    We demonstrate that ultrathin poly(4-vinylphenol) (PVP) acts as an effective organic seeding layer for atomic layer deposition (ALD) of high-k dielectric on large-scale graphene fabricated by chemical vapor deposition (CVD). While identical ALD conditions result in incomplete and rough dielectric deposition on CVD graphene, the reactive groups provided by the PVP seeding layer yield conformal and pinhole-free dielectric films throughout the large-scale graphene. Top-gate graphene field effect transistors fabricated with the high quality, PVP-seeded Al2O3 gate dielectric show superior carrier mobility and enhanced reliability performance, which are desirable for graphene nanoelectronics.

  17. Electrical Bistabilities and Memory Mechanisms of Organic Bistable Devices Fabricated Utilizing CdSe/ZnS Nanoparticles Embedded in Polystyrene and Poly(4-vinylphenol) Hybrid Composites

    NASA Astrophysics Data System (ADS)

    Son, Dong Ick; Yoo, Chan Ho; Jung, Jae Hun; Kim, Tae Whan

    2010-01-01

    The electrical bistabilities of core/shell CdSe/ZnS nanoparticles embedded in polystyrene (PS) and poly(4-vinylphenol) (PVP) hybrid polymer composites were investigated. Transmission electron microscopy images showed that CdSe/ZnS nanoparticles were formed inside the hybrid polymer matrix. Current-voltage (I-V) measurement at 300 K of Al/(PS + PVP)/(CdSe/ZnS nanoparticles)/(PS + PVP)/indium-tin oxide/glass devices showed electrical bistability behavior. The memory mechanisms of the organic bistable devices fabricated utilizing CdSe/ZnS nanoparticles embedded in hybrid polymer composites are described on the basis of the I-V results.

  18. Molecular composites via ionic interactions and their deformation/fracture properties

    SciTech Connect

    Parker, G.; Chen, W.; Hara, M.

    1995-12-01

    Homogeneous molecular composites have been made from ionic PPTA and PVP, in which a good dispersion of rod molecules is achieved via ion-dipole interactions. Appearance of a single T{sub g} as well as morphological observations by TEM have indicated good dispersion of the rigid-rod PPTA molecules. The deformation mode of the matrix polymer is modified significantly with the addition of rod molecules: while crazing is the only deformation mechanism of PVP, an addition of ionic PPTA molecules into the PVP matrix induces shear deformation. This suggests better fracture properties of these molecular composites. Initial studies have indicated significant enhancement in mechanical properties.

  19. Tageted bipolar radiofrequency decompression with vertebroplasty for intractable radicular pain due to spinal metastasis: a case report.

    PubMed

    Baek, Seong Jin; Park, Hahck Soo; Lee, Eun Young

    2016-08-01

    Metastatic spinal tumors are usually quite difficult to treat. In patients with metastatic spinal tumors, conventional radiotherapy fails to relieve pain in 20-30% of cases and open surgery often causes considerable trauma and complications, which delays treatment of the primary disease. Percutaneous vertebroplasty (PVP) is considered to be useful in achieving rapid pain control and preventing further vertebral collapse due to spinal metastasis. However, symptoms of intraspinal neural compression can be contraindications to PVP. To overcome this problem, we performed PVP following targeted bipolar radiofrequency decompression, and examined the effect of the combined treatment in relieving severe radicular pain related to spinal cord compression caused by malignant metastatic tumors. PMID:27482319

  20. Preparation of alumina rods by electrospinning aluminum sec-butoxide/polyvinylpyrrolidone blended solutions.

    PubMed

    Choi, Jinho; Yoon, Yongho; Jung, Jihoon

    2013-09-01

    Aluminum sec-butoxide/polyvinylpyrrolidone (ASB/PVP) solutions, prepared by sol-gel processing of a mixture of ASB and PVP, were electrospun to form ASB/PVP organic-inorganic hybrid fibers. The diameter of alumina nanofibers was in the range of 200 nm to 500 nm. Since the fibers cracked after calcinations at 1100 degrees C, they were cured at 300 degrees C, 400 degrees C and 500 degrees C for 24 h each. The calcination of these composite fibers at temperatures above 1000 degrees C resulted in pure rod-shaped a-alumina. It was analyzed by SEM, TG-DTA, FTIR, and XRD. PMID:24205637

  1. Dissolution enhancement of celecoxib via polymer-induced crystallization

    NASA Astrophysics Data System (ADS)

    Lee, Hyeseung; Lee, Jonghwi

    2013-07-01

    Pharmaceutical research and development critically rely on crystallization engineering principles since they influence the bioavailability, stability and processability of drug formulations. Although the polymer-induced crystallization has been intensively investigated in the area of inorganic materials, drug molecules have seldom been its subject. Celecoxib, which critically needed the improvement of bioavailability and processability, benefited from polymer-induced crystallization. Polyvinylpyrrolidone (PVP) and Pluronic successfully reduced the aspect ratio of celecoxib crystals to 1.5, which would improve processability. Among the polymers used, PVP distinctly improved the in vitro drug release behavior, which is consistent with the significant melting point depression and the polymorphic change in celecoxib crystallized with PVP. The strong hydrogen bonding between celecoxib and PVP is suspected as the origin of the improved crystal morphology and in vitro drug release. This polymer-induced crystallization can create new opportunities of convenient pharmaceutical particle engineering allowing reliable improvements in bioavailability and processability.

  2. Integrated antifouling and bactericidal polymer membranes through bioinspired polydopamine/poly(N-vinyl pyrrolidone) coating

    NASA Astrophysics Data System (ADS)

    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.

  3. Hydrophilic polymer composites synthesized by electrospinning under dense carbon dioxide

    NASA Astrophysics Data System (ADS)

    Wahyudiono, Okamoto, Koichi; Machmudah, Siti; Kanda, Hideki; Goto, Motonobu

    2015-12-01

    Electrospinning technique is feasible in some applications, it has attracted more attention in recent years. Various polymers have been successfully electrospun into ultrafine fibers in solvent solution and some in melt form. In this work, polyvinylpyrrolidone (PVP) as a hydrophilic polymer would be synthesized by electrospinning under dense carbon dioxide (CO2). The experiments were performed at 40 °C and ˜ 5 MPa. During the electrospinning process, the applied voltage was 10-17 kV and the distance of nozzle and collector was 8 cm. The concentration of PVP solution as a major component was 4 wt%. The results showed that the fibers surface morphology from PVP which blended with poly L-lactide acid (PLLA) were smooth with hollow core fibers at 5 MPa. At the same conditions, PVP-carbon nanotube was also successfully generated into electrospun fiber products with diameter ˜ 2 μm.

  4. Optical properties of Ag nanoparticle-polymer composite film based on two-dimensional Au nanoparticle array film

    NASA Astrophysics Data System (ADS)

    Wang, Long-De; Zhang, Tong; Zhang, Xiao-Yang; Song, Yuan-Jun; Li, Ruo-Zhou; Zhu, Sheng-Qing

    2014-03-01

    The nanocomposite polyvinyl pyrrolidone (PVP) films containing Ag nanoparticles and Rhodamine 6G are prepared on the two-dimensional distinctive continuous ultrathin gold nanofilms. We investigate the optical properties and the fluorescence properties of silver nanoparticles-PVP polymer composite films influenced by Ag nanoparticles and Au nanoparticles. Absorption spectral analysis suggests that the prominently light absorption in Ag nanowire/PVP and Ag nanowire/PVP/Au film arises from the localized surface plasmon resonance of Ag nanowire and Au nanofilm. The enhanced fluorescence is observed in the presence of Ag nanowire and Au nanofilm, which is attributed to the excitation of surface plasmon polariton resonance of Ag nanowire and Au nanofilm. The gold nanofilm is proven to be very effective fluorescence resonance energy transfer donors. The fabricated novel structure, gold ultrathin continuous nanofilm, possesses high surface plasmon resonance properties and prominent fluorescence enhancement effect. Therefore, the ultrathin continuous gold nanofilm is an active substrate on nanoparticle-enhanced fluorescence.

  5. Preparation and Characterization of Coaxial Electrospun Fibers Containing Triclosan for Comparative Study of Release Properties with Amoxicillin and Epicatechin.

    PubMed

    Rodríguez-Félix, D E; Castillo-Ortega, M M; Nájera-Luna, A L; Montaño-Figueroa, A G; López-Peña, I Y; Del Castillo-Castro, T; Rodríguez-Félix, F; Quiroz-Castilloc, J M; Herrera-Franco, P J

    2016-01-01

    The optimal conditions for the fibers preparation of cellulose acetate (CA) and poly(vinyl pyrrolidone) (PVP) containing triclosan within the fiber were successfully found; the physicochemical characteristics of these fibrous membranes were corroborated by FTIR spectroscopy, thermal analysis, mechanical tests, SEM , and TEM analysis. The formation of composite fibers of CA and PVP containing triclosan at the core of the fiber was evidenced. A comparative study of the release properties of amoxicillin, epicatechin or triclosan embedded into fibers CA/PVP/CA was performed. As more interactions of the drug with CA or PVP occur, slower release of the drug into the release medium takes place. Regarding the drug delivery system design, it is important to consider the possible molecular interactions between the material components and predict how fast or slow the drug will be delivered into the corresponding medium. PMID:26634788

  6. Prostate resection - minimally invasive

    MedlinePlus

    Laser prostatectomy; Transurethral needle ablation; TUNA; Transurethral incision; TUIP; Holmium laser enucleation of the prostate; HoLep; Interstitial laser coagulation; ILC; Photoselective vaporization of the prostate; PVP; Transurethral ...

  7. Determination of thickness and optical constants of solgel derived polyvinylpyrrolidone/ZrO2 films from transmission spectra using different dispersion models.

    PubMed

    Jia, Hongbao; Sun, Jinghua; Xu, Yao; Wu, Dong

    2012-10-10

    Transmission measurements have been used to investigate the optical properties of polyvinylpyrrolidone (PVP)/ZrO(2) films synthesized by the solgel route. The optical constants of PVP/ZrO(2) films deposited on quartz substrates were determined by fitting transmission spectra in the wavelength range of 200-800 nm with the Tauc-Lorentz and Cody-Lorentz physical models. Combined with Urbach tail, both models give a good description of transmission data and reveal that refractive index of film slightly decreases with increasing PVP mass fraction. X-ray reflectivity (XRR) measurements were also performed on PVP/ZrO(2) films to complement the thicknesses. The value of film thickness, including interface information from transmission spectra, is consistent with that result obtained from XRR, indicating that fitting transmission spectrum is a high reliable optical characterization. PMID:23052070

  8. Electrophoretic deposition of titanium dioxide films on copper in aqueous media.

    PubMed

    Laamari, M; Ben Youssef, A; Bousselmi, L

    2016-01-01

    Electrophoretic deposition was used to produce titanium dioxide (TiO2) nanostructured films on copper substrate in aqueous media for photocatalytic application. Polyvinyl pyrrolidone (PVP) with a weight rate from 0 to 15% was added to TiO2 P25 suspension in order to enhance film adhesion. The films were characterized by X-ray diffraction, optical microscopy, contact angle measurement, nanoindentation, scratch test and photoluminescence. The photocatalytic activity of the films was tested with amido black 10B under UV irradiation. The results indicated that the morphology and the mechanical properties of films depended on the added PVP amount. Scratch test showed that adhesion strength rose with increased PVP amount. The photocatalytic activity indicated that TiO2 film synthesized with 13% PVP had the highest efficiency. PMID:27438247

  9. Facile solvothermal synthesis of abnormal growth of one-dimensional ZnO nanostructures by ring-opening reaction of polyvinylpyrrolidone

    NASA Astrophysics Data System (ADS)

    Xu, G.; Wang, X. L.; Liu, G. Z.

    2015-02-01

    Abnormal growth of one-dimensional (1-D) ZnO nanostructures (NSs) have been accomplished with the assistance of polyvinylpyrrolidone (PVP) under a super high alkaline alcoholic solvothermal condition. The products were characterized by transmission electron microscopy (TEM), thermogravimetric analysis (TGA), X-ray diffraction (XRD), Fourier transform infrared (FT-IR) and proton nuclear magnetic resonance (1H NMR) spectroscopy. The effect of synthetic conditions, such as reaction temperature and the addition of PVP, on the morphologies of ZnO products were investigated. The results show that PVP molecules had the significant role in the transformation of morphologies of ZnO NSs ranging from nanorods, nanoparticles to pyramids, as well as flower-like assembly features. The possible growth mechanism of ZnO pyramids was proposed based on ring-opening reaction of PVP.

  10. pH-sensitive hydrogels

    SciTech Connect

    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.

  11. Improving Oral Bioavailability of Sorafenib by Optimizing the "Spring" and "Parachute" Based on Molecular Interaction Mechanisms.

    PubMed

    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

  12. Effect of the vehicle polyvinylpyrolidone and the Methanolic Fraction of Ligaria cuneifolia (Argentine Mistletoe) extract on hemorheological properties and biliary secretion in rats.

    PubMed

    Ferrero, Mariana; Crosetti, Diego; Dominighini, Alicia; de Luján Alvarez, María; Ronco, María Teresa; Wagner, Marcelo L; Gurni, Alberto; Carnovale, Cristina; Luquita, Alejandra

    2007-01-01

    Ligaria cuneifolia (R et P) Tiegh. (Loranthaceae) (Lc) aqueous extract-treated rats by via intraperitoneal (i.p.) show increased blood viscosity and decreased plasma cholesterol (Chol) levels. In this work, we analize the effect of the vehicle polyvinylpyrrolidone (PVP) and that of the Methanolic Fraction of the extract of Lc (MFLc) on hemorrheological properties in vivo and in vitro and on biliary excretion. For in vivo conditions, adult male Wistar rats were divided in five experimental groups (n=5 each one) which were injected, every 24 hr during 3 days by via i.p., with: (1) saline solution (Control); (2) PVP 0.47 mg/100 g bw; (3) MFLc 0.95 mg/100 g bw plus PVP 0.47 mg/100 g bw; (4) PVP 12.5 mg/100 g bw; and (5) MFLc 23.0 mg/100 g bw plus PVP 12.5 mg/100 g bw. Intended for in vitro conditions, blood samples obtained by heart puncture were divided into three fractions, which were incubated with: saline solution (Control), PVP 12.5 mg%, and MFLc 25 mg% plus PVP 12.5 mg%. We demonstrated a direct effect of PVP alone and of MFLc "per se" on the erythrocyte membrane resulting in a cell shape change from dyscocyte to spherostomatocyte (MI more negative) as well as a decrease in erythrocyte deformability (increased RI). These changes induce an increase in blood viscosity. Decreased plasma Chol is a consequence of an increased bile salts biliary excretion. PMID:17325433

  13. Low-temperature sintering behavior of nanocrystalline indium tin oxide prepared from polymer-containing sols

    SciTech Connect

    Koroesi, Laszlo; Papp, Szilvia; Oszko, Albert; Dekany, Imre

    2012-04-15

    Highlights: Black-Right-Pointing-Pointer The synthesis of ITO powders and thin films from PVP-containing sols is presented. Black-Right-Pointing-Pointer The nano- and microstructures of ITO are more compact when PVP is used. Black-Right-Pointing-Pointer PVP acts both as a steric stabilizer of the sol and as a pre-sintering agent. Black-Right-Pointing-Pointer The PVP-induced enhanced sintering results in ITO with lower electrical resistance. Black-Right-Pointing-Pointer The surface composition of the ITO films is independent of the initial PVP content. -- Abstract: Indium tin hydroxide (ITH) xerogel powders and thin films with different polyvinylpyrrolidone (PVP) contents (0-22%, w/w) were prepared by a classical sol-gel method. To obtain nanocrystalline indium tin oxide (ITO), the ITH xerogels were calcined at 550 Degree-Sign C. The effect of the initial polymer content on the structure of the ITO powders was studied by means of N{sub 2}-sorption measurements, small-angle X-ray scattering (SAXS), transmission and scanning electron microscopy. The N{sub 2}-sorption measurements revealed that the ITO powders obtained contained micropores and both their porosity and specific surface area decreased with increasing PVP content of the ITH xerogels. The SAXS measurements confirmed the enhanced sintering of the particles in the presence of PVP. The calculated mass fractal dimensions of the ITO powders increased significantly, indicating a significant compaction in structure. The pre-sintered structure could be achieved at relatively low temperature, which induced a significant decreasing (three orders of magnitude) in the electrical resistance of the ITO films.

  14. Longer storage of dialyzers increases elution of poly(N-vinyl-2-pyrrolidone) from polysulfone-group dialysis membranes.

    PubMed

    Namekawa, Koki; Kaneko, Ami; Sakai, Kiyotaka; Kunikata, Satoru; Matsuda, Masato

    2011-03-01

    The objective of this study was to evaluate the effect of protracted storage of dialyzers on the amount of poly(N-vinyl-2-pyrrolidone) (PVP) eluted from polysulfone-group dialysis membranes. We tested five dialysis membranes: APS-15SA (Asahi Kasei Kuraray, wet), CX-1.6U (Toray, moist), FX140 (Fresenius, dry), PES-15Sα (Nipro, dry), and FDX-150GW (Nikkiso, wet). Each dialyzer was stored for 1, 3, 14, and 18 months after sterilization. The dialysis-fluid side compartment was primed with reverse osmosis (RO) water at 500 mL/min for 5 min at 310 K. The blood side compartment was primed with RO water at 200 mL/min for 5 min at 310 K. Finally, 1 L RO water was circulated through the blood side compartment at 200 mL/min for 4 h at 310 K. Eluted PVP was determined by use of the iodine method, using 0.02 N: iodine solution. PVP was mainly eluted from wet-type dialyzers during priming. Thus, the standard 5 min priming of the wet-type dialyzer according to the maker manual inhibits PVP elution during circulation. PVP was eluted in the dialysis-fluid side of the moist-type dialyzer during priming but no PVP was eluted in the blood side. PVP was mainly eluted from dry-type dialyzers during circulation. We recommend more than the standard 5 min priming, particularly for dry-type dialyzers stored for protracted periods, because 5 min insufficient to inhibit PVP elution during circulation. PMID:21286768

  15. Synthesis of different copper nanostructures by the use of polyol technique

    NASA Astrophysics Data System (ADS)

    Hosseini, Maryamsadat; Fatmehsari, Davoud Haghshenas; Marashi, Seyed Pirooz Hoveida

    2015-09-01

    Self-seeding polyol synthesis method, without additives, was employed for the fabrication of different copper nanostructures. The pertinent parameters including temperature, copper concentration and molar ratio of poly(vinylpyrrolidone) (PVP) to copper were assessed for achieving different size and morphology of copper nanostructures, i.e., nanowire, nanosphere and nanocube. It was found that PVP-to-copper molar ratio has the most significant effect on the geometry of the copper nanostructures.

  16. Enzyme-free Detection of Hydrogen Peroxide from Cerium Oxide Nanoparticles Immobilized on Poly(4-vinylpyridine) Self-Assembled Monolayers

    SciTech Connect

    Gaynor, James D.; Karakoti, Ajay S.; Inerbaev, Talgat; Sanghavi, Shail P.; Nachimuthu, Ponnusamy; Shutthanandan, V.; Seal, Sudipta; Thevuthasan, Suntharampillai

    2013-05-02

    A single layer of oxygen-deficient cerium oxide nanoparticles (CNPs) are immobilized on microscopic glass slide using poly(4-vinylpyridine) (PVP) self-assembled monolayers (SAMs). A specific colorimetric property of CNPs when reacted with hydrogen peroxide allows for the direct, single-step peroxide detection which can be used in medical diagnosis and explosives detection. Multiple PVP-CNP immobilized layers improve sensitivity of detection and the sensor can be regenerated for reuse.

  17. Polyvinylpyrrolidone microneedles enable delivery of intact proteins for diagnostic and therapeutic applications

    PubMed Central

    Sun, Wenchao; Araci, Zeynep; Inayathullah, Mohammed; Manickam, Sathish; Zhang, Xuexiang; Bruce, Marc A.; Marinkovich, M. Peter; Lane, Alfred T.; Milla, Carlos; Rajadas, Jayakumar; Butte, Manish J.

    2013-01-01

    We present a method of fabricating microneedles from polyvinylpyrrolidone (PVP) that enables delivery of intact proteins (or peptides) to the dermal layers of the skin. PVP is known to self-assemble into branched hollow fibers in aqueous and alcoholic solutions; we utilized this property to develop dissolvable patches of microneedles. Proteins were dissolved in concentrated PVP solution in both alcohol and water, poured into polydimethylsiloxane templates shaped as microneedles and, upon evaporation of solvent, formed into concentric, fibrous, layered structures. This approach of making PVP microneedles overcomes problems in dosage, uniform delivery and stability of protein formulation as compared to protein-coated metallic microneedles or photopolymerized PVP microneedles. Here we characterize the PVP microneedles and measure the delivery of proteins into skin. We show that our method of fabrication preserves the protein conformation. These microneedles can serve as a broadly useful platform for delivering protein antigens and therapeutic proteins to the skin, for example for allergen skin testing or immunotherapy. PMID:23648574

  18. A novel solution process for the synthesis of VO2 thin films with excellent thermochromic properties.

    PubMed

    Kang, Litao; Gao, Yanfeng; Luo, Hongjie

    2009-10-01

    This article describes a novel and simple route to preparing VO(2) thermochromic films by using a VOCl(2) solution with poly(vinylpyrrolidone) (PVP). X-ray diffraction and Raman spectra showed that the VO(2) films deposited with PVP consisted of a nearly pure monoclinic/rutile (M/R) phase. Conversely, films prepared without PVP contained obviously impure crystalline phases. The as-prepared films with PVP showed excellent optical properties compared to those prepared by common gas-phase methods: an integral visible transmittance of 54.5% and an IR reduction (change in transmittance) of 41.5% at 2000 nm. The phase-transition temperatures were adjusted from 69 to 54 degrees C by tungsten doping. Equipment analyses revealed that PVP plays two roles in the film formation. First, it fundamentally acts as a film-forming promoter to improve physical gelation via interactions among oppositely charged carbonyl groups and amine groups of the polymer. Second, the negatively charged carbonyl groups can interact with VO(2+) to form a uniform mixed-gel film after solvent evaporation. Thus, the addition of PVP can stabilize the solution and improve the as-prepared film quality and phase purity. The current study suggests that the process has promise in applications of smart windows. PMID:20355855

  19. Preparation and characterization of cefuroxime axetil solid dispersions using hydrophilic carriers

    PubMed Central

    Gorajana, Adinarayana; Rajendran, Adhiyaman; Yew, Lee Mun; Dua, Kamal

    2015-01-01

    Aim: The objective of the current study is to increase the dissolution rate of cefuroxime axetil (CA) by formation of binary CA solid dispersion using water soluble carriers such as polyvinylpyrrolidone (PVP K30) and polyethylene glycol (PEG 4000). Methods: Solid dispersions (SDs) between CA and PVP K30/PEG 4000 were formed by dissolving both compounds in a common solvent, methanol, which were rotary evaporated at 40°C for 12 h. Physical mixtures between CA and PVP K30/PEG 4000 were also formulated as to compare the efficiency of SDs. The physicochemical properties of CA and all its formulations were then characterized using differential scanning calorimetric analysis (DSC), powder X-ray diffraction studies (PXRD), and Fourier transform infrared spectroscopy (FTIR). Results: All SD formulations were found to have a higher dissolution rate comparatively to pure CA, while only physical mixtures of PVP K30 were found having a significantly higher dissolution rate. The enhancement of dissolution rate SD by PVP K30 may be caused by increase wettability, solubility, reduction in particle size or the formation of CA β crystalline. Increment of dissolution rate of CA SDs by PEG 4000 similarly may be caused by increase wettability, solubility, and reduction in particle size. This phenomenon may also be caused by amorphization as suggested by DSC and PXRD. Conclusions: The SD of CA with PVP K30 and PEG 4000, lends an ample credence for better therapeutic efficacy. PMID:26258059

  20. Polyvinylpyrrolidone/polyvinyl butyral composite as a stable binder for castable supercapacitor electrodes in aqueous electrolytes

    NASA Astrophysics Data System (ADS)

    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.

  1. Silver-assisted chemical etching on silicon with polyvinylpyrrolidone-mediated formation of silver dendrites.

    PubMed

    Chen, Chia-Yun; Hsiao, Po-Hsuan

    2015-02-23

    Metal-assisted chemical etching (MaCE) on silicon (Si)-mediated by polyvinylpyrrolidone (PVP)-is systematically investigated herein. It is found that the morphologies and crystallographic natures of the grown silver (Ag) dendrites can be significantly modulated, with the presence of PVP in the MaCE process leading to the formation of faceted Ag dendrites preferentially along the (111) crystallographic phase, rather than along the (200) phase. Further explorations of the PVP-mediated effect on Si etching are also revealed. In contrast to the aligned Si nanowires formed by MaCE without PVP addition, only distributed nanopores with sizes of 200 to 400 nm appear on the Si surfaces in the presence of PVP. The origin of surface polishing on Si in the PVP-mediated MaCE process can be attributed to the distinct transport pathway of holes supplied by the Ag(+) ions, where the holes are injected directly into the primary Ag seeds, rather than through Ag dendrites, thus leading to the isotropic etching of the Si surface. PMID:25521287

  2. Percutaneous vertebroplasty: the radiologist’s point of view

    PubMed Central

    Masala, Salvatore; Mammucari, Matteo; Fucci, Francesco Paolo Maria; Massari, Francesco; Simonetti, Giovanni

    2010-01-01

    Introduction: Vertebral compression fractures (VCFs), usually caused by osteoporosis, is a disabling pathology associated with back pain, low quality of life and high costs. We report a retrospective study of 852 patients who underwent Percutaneous Vertebroplasty (PVP) in our department, for treatment of refractory back pain caused by osteoporotic vertebral fractures. Objectives: To evaluate the safety and the helpfulness of the PVP in vertebral osteoporotic fractures treatment and, particularly on durable pain reduction, mobility improvement and analgesic drugs need. Materials and Methods: Follow-up analysis was made through a questionnaire filled by the patients before and after PVP (1-6 months), designed to measure pain, ambulation capacity, ability to perform activities of daily living (ADL) and analgesic drugs administration. Results: A statistically significant difference between visual analogue scale (VAS) values before and after treatment has been observed. No difference between VAS values were observed at 1 and 6 months post-treatment period. The treated vertebrae number did not influence post-treatment VAS values during all the follow-up. Ambulation capacity and the ability to perform ADL have been improved following PVP. Patients also reported significant reduction in administration of medications after PVP. Conclusions: PVP is a safe and useful procedure in painful osteoporotic VCFs treatment, able to reduce pain, improve patients mobility and decrease analgesic drugs need. PMID:22461290

  3. Development of Itraconazole Liquisolid Compact: Effect of Polyvinylpyrrolidone on the Dissolution Properties.

    PubMed

    Gong, Wei; Wang, Yuli; Sun, Lei; Yang, Jiahui; Shan, Li; Yang, Meiyan; Gao, Chunsheng

    2016-01-01

    The aim of this work was to utilize the liquisolid technique to enhance dissolution of itraconazole (ITZ). Liquisolid tablets of ITZ were formulated by using N-methyl-2-pyrrolidone as liquid vehicle, polyvinylpyrrolidone (PVP) as a precipitation inhibitor and magnesium aluminometasilicate Neusilin® as a carrier and coating material. The effect of PVP level on stability of liquid medication, physicomechnanical properties and dissolution rate of liquisolid compacts was studied in detail. The crystallinity of formulated drug and the interaction between excipients were examined by differential scanning calorimetry (DSC) and X-ray powder diffraction (XRPD). All the liquisolid tablets showed higher drug dissolution rates than the conventional, directly compressed tablets. The flowability of liquisolid powders was slightly improved as the proportion of PVP in ITZ-NMP mixture increased. Moreover, the stability of liquid medication and wetting ability of liquisolid tablets were improved by PVP. The presence of low amount of PVP (≤ 1%) in liquisolid formulation could enhance dissolution of ITZ liquisolid tablets, whereas the percentage of PVP over 5% decreased the dissolution of ITZ from liquisolid tablets. Both DSC and XRPD suggested reduction or loss of ITZ crystallinity upon liquisolid formulations indicating that the drug was almost solubilized and molecularly dispersed with excipients within the liquisolid matrix. It could be shown that increased solubility, wetting properties and surface area available for dissolution contributed to the improvement of the dissolution of ITZ from liquisolid tablets. PMID:26882116

  4. Silver polyvinyl pyrrolidone nanoparticles exhibit a capsular polysaccharide influenced bactericidal effect against Streptococcus pneumoniae

    PubMed Central

    Bibbs, Ronda K.; Harris, Rhonda D.; Peoples, Veolanda A.; Barnett, Cleon; Singh, Shree R.; Dennis, Vida A.; Coats, Mamie T.

    2014-01-01

    Streptococcus pneumoniae remains a leading cause of morbidity and mortality worldwide. The highly adaptive nature of S. pneumoniae exemplifies the need for next generation antimicrobials designed to avoid high level resistance. Metal based nanomaterials fit this criterion. Our study examined the antimicrobial activity of gold nanospheres, silver coated polyvinyl pyrrolidone (AgPVP), and titanium dioxide (TiO2) against various serotypes of S. pneumoniae. Twenty nanometer spherical AgPVP demonstrated the highest level of killing among the tested materials. AgPVP (0.6 mg/mL) was able to kill pneumococcal serotypes 2, 3, 4, and 19F within 4 h of exposure. Detailed analysis of cultures during exposure to AgPVP showed that both the metal ions and the solid nanoparticles participate in the killing of the pneumococcus. The bactericidal effect of AgPVP was lessened in the absence of the pneumococcal capsular polysaccharide. Capsule negative strains, JD908 and RX1, were only susceptible to AgPVP at concentrations at least 33% higher than their respective capsule expressing counterparts. These findings suggest that mechanisms of killing used by nanomaterials are not serotype dependent and that the capsular polysaccharide participates in the inhibition. In the near future these mechanisms will be examined as targets for novel antimicrobials. PMID:25520713

  5. Preparation and Characterization of Polymer-Stabilized Ruthenium-Platinum and Ruthenium-Palladium Bimetallic Colloids and Their Catalytic Properties for Hydrogenation of o-Chloronitrobenzene.

    PubMed

    Liu; Yu; Liu; Zheng

    1999-06-15

    Colloidal dispersions of poly(N-vinyl-2-pyrrolidone) (PVP)-stabilized ruthenium-platinum and ruthenium-palladium bimetallic colloids were prepared by NaBH4 reduction of the corresponding mixed-metal salts at room temperature and characterized by TEM, XPS, and XRD. The resulting bimetallic colloids were used as catalysts for the selective hydrogenation of o-chloronitrobenzene (o-CNB) in methanol at 303 K under 0.1 MPa of hydrogen. It was observed that the catalytic performance of PVP-stabilized ruthenium-platinum colloids (PVP-Ru/Pt) and ruthenium-palladium colloids (PVP-Ru/Pd) was dependent on their compositions and could be remarkably affected by some added metal cations. In the presence of cobalt ion, nearly 100% selectivity to o-chloroaniline (o-CAN) was achieved over PVP-Ru/Pt colloids at 100% conversion of o-CNB, with an activity two orders of magnitude higher than that of monometallic PVP-Ru colloid. Copyright 1999 Academic Press. PMID:10339363

  6. Monodisperse polyvinylpyrrolidone-coated CoFe2O4 nanoparticles: Synthesis, characterization and cytotoxicity study

    NASA Astrophysics Data System (ADS)

    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.

  7. Correlation between lead retention and intestinal pinocytosis in the suckling mouse

    SciTech Connect

    Keller, C.A.; Doherty, R.A.

    1980-01-01

    Young animals absorb and retain a greater fraction of an oral dose of lead than do adult animals. It has been proposed that pinocytotic activity in young animals is partially responsible for the increased lead retention and absorption. Radiolabeled lead (5 mg/kg) and polyvinylpyrrolidone (PVP, 50 mg/kg) were administered orally to 12-day-old suckling mice and to adult mice, and the uptake of lead and PVP was determined periodically during a 6-day interval. Intestinal tissue from the distal jejunum and ileum were found to contain the greatest quantities of both lead and PVP. Pretreatment of suckling mice with cortisone acetate resulted in decreased content of lead and PVP within tissue of the intestine, and decreased whole-body lead retention. Cortisone pretreatment produced lower lead concentrations in blood, brain, kidney, and liver. Lead and PVP uptake into intestinal tissue of adult mice was much less than uptake in suckling pups. Cortisone pretreatment of adult mice had no effect on whole-body lead retention or intestinal tissue content of lead or PVP.

  8. DISSOLUTION AND COMPATIBILITY STUDY OF BINARY AND TERNARY INTERACTIVE MIXTURES OF INDOMETHACIN: COMPARISON WITH COMMERCIALLY AVAILABLE CAPSULES.

    PubMed

    Maswadeh, Hamzah M

    2016-01-01

    The main objective of this work was to use Weibull distribution function and Baker-Lonsdale models to study the dissolution kinetics of prepared binary and ternary interactive mixtures containing indomethacin in comparison with three commercially available capsules of indomethacin, namely, Rothacin®, Indomin® and Indylon®. Differential scanning calorimetry (DSC) in conjunction with cloud point method was used to study the compatibility of indomethacin with polyvinylpyrrolidone (PVP) and lactose and to provide an explanation(s) for the insignificant increase in dissolution rate observed in the ternary interactive mixture as well as for the reduction in the dissolution rate observed from the binary system in our previous study. Results showed that the Weibull distribution function equation was the best fit to the dissolution data for all formulations used in this study. DSC curves showed that the decrease in dissolution rate from the binary and ternary interactive mixtures was due to incompatibility of indomethacin with PVP. Also DSC curves showed that lactose was compatible with indomethacin and that lactose was used as excipient in two commercial products (Rothacin® and Indylon®). Results from the cloud point method showed that the addition of indomethacin to 1% PVP solution containing ammonium sulfate (with cloud point at 76°C) reduces the cloud point of PVP indicating that there is an interaction between indomethacin and PVP, while the cloud point of 1% PVP containing ammonium sulfate was not affected by the addition of lactose. PMID:27476292

  9. Macrophage function as studied by the clearance of /sup 125/I-labeled polyvinylpyrrolidone in iron-deficient and iron-replete mice

    SciTech Connect

    Kuvibidila, S.; Wade, S.

    1987-01-01

    This study evaluated the effects of iron deficiency and iron repletion on in vivo macrophage function determined by the clearance of /sup 125/I-labeled polyvinylpyrrolidone (PVP). Two experiments were done. There were four groups of C57BL/6 female mice in experiment 1: the iron-deficient (ID), pair-fed (PF), control (C) and the high iron (HI) groups. In experiment 2, there were three ID groups (severe to moderate anemia), three PF, one C and four ID groups that were fed adequate iron for 14 (R-14), 7 (R-7), 3 (R-3) days before or on the day of PVP injection (R-0). The overall rate of PVP clearance from blood was lower in ID than in C or PF groups. This clearance is expressed by a constant, K, calculated from natural log (ln) of the cpm and the time postadministration of PVP that blood was drawn. The theoretical individual macrophages function (alpha PVP), derived from K and the weights of body, spleen and liver, was also lower in ID than in C or PF groups. The impairment was most severe with the most severe iron deficiency. Repletion for 7 to 15 d before PVP administration resulted in a partial correction of the clearance. Moderate undernutrition in the PF group had no effect.

  10. Poly(vinyl pyrrolidone): a dual functional reductant and stabilizer for the facile synthesis of noble metal nanoplates in aqueous solutions.

    PubMed

    Xiong, Yujie; Washio, Isao; Chen, Jingyi; Cai, Honggang; Li, Zhi-Yuan; Xia, Younan

    2006-09-26

    Poly(vinyl pyrrolidone) (PVP) has been extensively used in the solution-phase synthesis of many types of colloidal particles, where it is mainly considered as a steric stabilizer or capping agent with a major role to protect the product from agglomeration. In a recent study, we discovered that the hydroxyl end groups of PVP could also serve as a very mild reductant for kinetically controlled synthesis of Ag nanoplates with yields as high as 75%. Here we further demonstrate that hydroxyl-terminated PVP is also a well-suited reductant for the aqueous synthesis of circular, triangular, and hexagonal nanoplates made of other noble metals including Pd, Au, and Pt. The reduction kinetics of a metal salt by the hydroxyl end groups of PVP can be maneuvered in at least two different ways to facilitate the evolution of plate morphology: (i) by adjusting the molar ratio of PVP to the salt precursor and (ii) by altering the molecular weight of PVP. Unlike previously reported studies of Ag and Au thin plates, light was found to have a negligible role in the present synthesis. PMID:16981776

  11. Hydrothermal effect and mechanical stress properties of carboxymethylcellulose based hydrogel food packaging.

    PubMed

    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. PMID:25498671

  12. Comparison of the effect of chitosan and polyvinylpyrrolidone on dissolution properties and analgesic effect of naproxen.

    PubMed

    Zerrouk, Naima; Mennini, Natascia; Maestrelli, Francesca; Chemtob, Chantal; Mura, Paola

    2004-01-01

    The solubilizing and absorption enhancer properties towards naproxen of chitosan and polyvinylpyrrolidone (PVP) have been investigated. Solid binary systems prepared at various drug-polymer ratios by mixing, cogrinding or kneading, were characterized by differential scanning calorimetry, X-ray diffractometry, Fourier transform infrared spectroscopy, and scanning electron microscopy, and tested for dissolution behavior. Both carriers improved drug dissolution and their performance depended on the drug-polymer ratio and the system preparation method. Chitosan was more effective than PVP, despite the greater amorphizing power of PVP as revealed by solid state analyses. The 3/7 (w/w) drug-carrier coground systems with chitosan and PVP were the best products enabling, respectively, an improvement of 4.8 and 3.6 times of drug dissolution efficiency. In vivo experiments in mice demonstrated that administration of 45 mg/kg of drug coground with PVP or chitosan resulted, respectively, in a 25 and 60% reduction of acetic acid-induced writhings in comparison to pure drug, which, instead, was statistically ineffective as compared to the control group. Moreover, the 3/7 (w/w) drug-chitosan coground product demonstrated an antiwrithing potency 2.4 times higher than the coground with PVP. Thus, the direct-compression properties and antiulcerogenic activity, combined with the demonstrated solubilizing power and analgesic effect enhancer ability towards the drug, make chitosan particularly suitable for developing a reduced-dose fast-release solid oral dosage form of naproxen. PMID:14729084

  13. Evolution of structure and properties of granules containing microcrystalline cellulose and polyvinylpyrrolidone during high-shear wet granulation.

    PubMed

    Osei-Yeboah, Frederick; Feng, Yushi; Sun, Changquan Calvin

    2014-01-01

    Granulation behavior of microcrystalline cellulose (MCC) in the presence of 2.5% polyvinylpyrrolidone (PVP) was systematically studied. Complex changes in flowability and tabletability of lubricated MCC granules are correlated to changes in intragranular porosity, morphology, surface smoothness, size distribution, and specific surface area (SSA). With 2.5% PVP, the use of 45% granulation water leads to 84% reduction in tablet tensile strength and 76% improvement in powder flow factor. The changes in powder performance are explained by granule densification and surface smoothing. The granulating water level corresponding to the onset of overgranulation, 45%, is significantly lower than the 70% water required for unlubricated MCC granules without PVP. At more than 45% water levels, MCC-PVP granules flow well but cannot be compressed into intact tablets. Such changes in powder performance correspond to the rapid growth into large and dense spheres with smooth surface. Compared with MCC alone, the onset of the phase of fast granule size enlargement occurs at a lower water level when 2.5% PVP is used. Although the use of 2.5% PVP hastens granule nucleation and growth rate, the mechanisms of overgranulation are the same, that is, size enlargement, granule densification, surface smoothing, and particle rounding in both systems. PMID:24218097

  14. Percutaneous vertebroplasty immediately relieves pain of osteoporotic vertebral compression fractures and prevents prolonged immobilization of patients.

    PubMed

    Kobayashi, Kiyokazu; Shimoyama, Keiji; Nakamura, Keiya; Murata, Kiyoshi

    2005-02-01

    To assess the immediate efficacy of percutaneous vertebroplasty (PVP) in relief of pain and improving mobility of patients with vertebral compression fractures (VCF) secondary to osteoporosis, 205 cases (175 patients) underwent 250 percutaneous injections of polymethylmethacrylate (PMMA; unilateral, 247 levels; bilateral, 3 levels) into vertebrae under CT and fluoroscopic guidance for 34 months. Patients were prospectively asked to quantify their pain on a visual analog scale (VAS) before and a day after PVP. The interval to mobilization was recorded in those who were immobilized because of pain and/or bed-rest therapy (115 cases). PVP was technically successful in all patients, with three cases of minimal complications. The mean VAS score available for 196 cases was improved from 7.22+/-1.89 (range, 3-10) to 2.07+/-1.19 (range, 0-10) by PVP. Ninety-four of 115 immobilized cases (81.7%) were mobile by 24 h after PVP, and the mean value was 1.9+/-2.8 days. The incidence of recurrent and new fractures was 15.6% in 4-25 months (mean, 15.3 months). PVP is a safe and effective treatment for relieving the pain associated with osteoporotic VCF and strengthening the vertebrae, avoiding refractures. This therapy leads to early mobilization and avoidance of the dangers of conservative therapy of bed-rest. PMID:15662480

  15. Electrophoretic deposition of tannic acid-polypyrrolidone films and composites.

    PubMed

    Luo, Dan; Zhang, Tianshi; Zhitomirsky, Igor

    2016-05-01

    Thin films of polyvinylpyrrolidone (PVP)-tannic acid (TA) complexes were prepared by a conceptually new strategy, based on electrophoretic deposition (EPD). Proof of concept investigations involved the analysis of the deposition yield, FTIR and UV-vis spectroscopy of the deposited material, and electron microscopy studies. The analysis of the deposition mechanism indicated that the limitations of the EPD in the deposition of small phenolic molecules, such as TA, and electrically neutral polymers, similar to PVP, containing hydrogen-accepting carbonyl groups, can be avoided. The remarkable adsorption properties of TA and film forming properties of the PVP-TA complexes allowed for the EPD of materials of different types, such as huntite mineral platelets and hydrotalcite clay particles, TiO2 and MnO2 oxide nanoparticles, multiwalled carbon nanotubes, TiN and Pd nanoparticles. Moreover, PVP-TA complexes were used for the co-deposition of different materials and formation of composite films. In another approach, TA was used as a capping agent for the hydrothermal synthesis of ZnO nanorods, which were then deposited by EPD using PVP-TA complexes. The fundamental adsorption and interaction mechanisms of TA involved chelation of metal atoms on particle surfaces with galloyl groups, π-π interactions and hydrogen bonding. The films prepared by EPD can be used for various applications, utilizing functional properties of TA, PVP, inorganic and organic materials of different types and their composites. PMID:26878711

  16. Efficacy of Percutaneous Vertebroplasty in the Treatment of Osteoporotic Vertebral Compression Fractures with Intravertebral Cleft

    PubMed Central

    Nakamae, Toshio; Fujimoto, Yoshinori; Yamada, Kiyotaka; Hashimoto, Takashi; Olmarker, Kjell

    2015-01-01

    Intravertebral cleft (IVC) is frequently observed in patients with painful osteoporotic vertebral compression fracture (OVCF). Some studies reported the usefulness of percutaneous vertebroplasty (PVP) for treating OVCF with IVC. However, systematic studies are scarce, and their results are conflicting. The purpose of this study was to evaluate the clinical and radiographic results of PVP in the treatment of painful OVCF with IVC. Two hundred ninety-one patients with OVCF with IVC underwent PVP. Back pain was measured using a visual analog scale (VAS), and physical disability was assessed using the Oswestry Disability Index (ODI). Three radiological parameters were assessed: the local kyphotic angle, percentage spinal canal cross-sectional area of compromise, and intravertebral instability of the affected vertebra. The mean follow-up period was 28 months. The mean values for the VAS and ODI were 8.4 and 60.0%, respectively, before PVP, versus 3.9 and 35.4%, respectively, at the final follow-up. The average local kyphotic angle, percentage spinal canal cross-sectional area of compromise, and intravertebral instability were 10.5°, 17.9% and 6.1°, respectively, before PVP and 8.1°, 15.2%, and 0.8°, respectively, at the final follow-up. There were no neurological or systemic complications due to cement leakage. PVP is an effective and safe intervention for treating OVCF with IVC. PMID:26157525

  17. Assemblies of polyvinylpyrrolidone-capped tetrahedral and spherical Pt nanoparticles in polyelectrolytes: hydrogen underpotential deposition and electrochemical characterization.

    PubMed

    Jaber, Sarah; Nasr, Pamela; Xin, Yan; Sleem, Fatima; Halaoui, Lara I

    2013-09-28

    Polyvinylpyrrolidone (PVP)-capped Pt nanoparticles (NPs) were synthesized in mostly tetrahedral (TH-Pt, [edge] = 4.3 ± 0.7 nm) or spherical (S-Pt, [d] = 3.4 ± 0.8 nm) shapes and assembled layer-by-layer in poly(diallyldimethylammonium) chloride on electrodes driven by electrostatic and hydrophobic interactions. The nanostructured Pt electrodes were characterized using hydrogen underpotential deposition (H(upd)) in 1 M H2SO4. The H(upd) charge increased linearly with the PDDA-Pt NP adsorption cycle measured up to 10 cycles revealing a linear incorporation of Pt NPs per cycle, indicative of reproducible surface charge reversal despite the submonolayer NP coverage imaged by TEM on a PDDA layer, and showing the feasibility of charge and mass transport in the thickness of the films. H(upd) at both PVP-TH-Pt and PVP-S-Pt occurred in two states, a major weak-adsorption H(W) peak, and a minor strong-adsorption state H(S) appearing as a shoulder. H(upd) features and other electrochemical processes at assemblies of PVP-Pt NP in PDDA were compared to assemblies of 2.5 nm polyacrylate-capped Pt NPs in PDDA and to polycrystalline Pt. Results indicated that H(W) adsorption likely occurs on a PVP-modified Pt NP surface without being accompanied by PVP desorption, while H(S) occurs on free (100) sites. The PVP-Pt NPs were resistant to surface oxidation and were stable against usual surface restructuring when scanned into the Pt-oxide potential region as they remained modified with PVP. O2 evolution was also suppressed by PVP-capping compared to PAC-Pt NPs and polycryst-Pt, but the assemblies were electrocatalytic for hydrogen evolution, hydrogen oxidation, and oxygen reduction. Increasing anodic polarization increased the H(W) charge but without causing a potential shift, indicating absence of PVP decapping or Pt surface restructuring, but possibly some structural polymer rearrangement increasing the accessibility of buried sites for H-adsorption. PMID:23928658

  18. Mechanochemical activation of vincamine mediated by linear polymers: assessment of some "critical" steps.

    PubMed

    Hasa, Dritan; Perissutti, Beatrice; Grassi, Mario; Chierotti, Michele R; Gobetto, Roberto; Ferrario, Valerio; Lenaz, Davide; Voinovich, Dario

    2013-09-27

    The aim of the research was to investigate three "critical steps" that deserve particular attention during the mechanochemical activation of vincamine. The first step consisted in the selection of the best polymeric carrier/most affine stabiliser between linear PVP and NaCMC by using the GRID and the GRID based AutoDock software packages which permit to calculate their surface features and interactions. Moreover, the calculation of the partial and total solubility parameters supported the results obtained by GRID and AutoDock software. Then, after the selection of linear PVP-K30 as the suitable carrier, the influence of process and formulation variables on the amorphisation degree and solubility enhancement was studied, to select the most suitable process conditions and formulation parameters. Subsequently, the best performing samples were widely characterised using XRPD, TEM and SSNMR (including the proton relaxation ((1)H T1 NMR) time) techniques. These studies highlighted that all the coground samples were nanocrystalline solid dispersions indicating a dramatic difference between the amorphisation capacities of linear PVP-K30 and cross-linked PVP, used in previous analogous experiences. In particular, (13)C, (15)N and (1)H T1 NMR data point to a description of the system as a dispersion of nanocrystals in the polymer. In these dispersions vincamine is in a disordered crystalline state due to extensive interactions and contacts with PVP-K30 but the main hydrogen bonding motif characterising its packing remains. Again, differently from cross-linked PVP, dissolution studies revealed that linear PVP-K30 was able to promote a complete in vitro solubilisation of vincamine in some coground samples. What is more important, by using a linear polymer, drug-to-polymer and milling time variables appeared less influent on the solid state and in vitro properties of the composites. Finally, stability studies conducted for a period of 1year highlighted the high physical

  19. Controllable synthesis and growth mechanism of {alpha}-Co(OH){sub 2} nanorods and nanoplates by a facile solution-phase route

    SciTech Connect

    Wang Wenzhong; Feng Kai; Wang Zhi; Ma Yunyan; Zhang Suyun; Liang Yujie

    2011-12-15

    A facile chemical precipitation route has been developed to control synthesis of {alpha}-cobalt hydroxide nanostructures with rod-like and plate-like morphologies. The {alpha}-Co(OH){sub 2} nanorods were achieved in large quantity when the experiments were carried out in the presence of a suitable shape-controlling reagent polyvinyl pyrrolidone (PVP), while the {alpha}-Co(OH){sub 2} nanoplates were obtained when the experiments were conducted in the absence of PVP, whilst keeping other experimental conditions constant. The chemical composition and morphologies of the as-prepared {alpha}-Co(OH){sub 2} nanoparticles were characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The effect of polymer PVP on the morphologies of {alpha}-Co(OH){sub 2} nanoparticles were discussed in detail. The results indicated that PVP played a key role for the formation of {alpha}-Co(OH){sub 2} nanorods. The growth mechanism of the as-synthesized nanorods and nanoplates were discussed in detail based on the experimental results. A possible growth mechanism has been proposed to illustrate the growth of {alpha}-Co(OH){sub 2} nanorods. - Graphical abstract: A facile solution-phase route has been developed to synthesize {alpha}-Co(OH){sub 2} nanorods and nanoplates. The possible growth mechanism of nanorods and nanoplates was proposed. Highlights: Black-Right-Pointing-Pointer A facile controllable route was described for {alpha}-Co(OH){sub 2} nanowires and nanoplates. Black-Right-Pointing-Pointer The {alpha}-Co(OH){sub 2} nanowires were achieved in the presence of shape controller PVP. Black-Right-Pointing-Pointer The {alpha}-Co(OH){sub 2} nanoplates were obtained in the absence of shape controller PVP. Black-Right-Pointing-Pointer The shape controller PVP played a key role in the formation of {alpha}-Co(OH){sub 2} nanowires.

  20. Effects of fluid flow on elution of hydrophilic modifier from dialysis membrane surfaces.

    PubMed

    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. PMID:18836876

  1. Multivalent virus-like-particle vaccine protects against classic and variant infectious bursal disease viruses.

    PubMed

    Jackwood, Daral J

    2013-03-01

    Nucleotide sequences that encode the pVP2 proteins from a variant infectious bursal disease virus (IBDV) strain designated USA08MD34p and a classic IBDV strain designated Mo195 were produced with the use of reverse-transcriptase-polymerase chain reaction (RT-PCR) and cloned into a pGEM-T Easy vector. A nucleotide sequence that encodes the VP3 protein was also produced from the USA08MD34p viral genome with the use of RT-PCR and cloned into a pGEM-T Easy vector. The VP3 and pVP2 clones were inserted into the pVL1393 baculovirus transfer vector and sequenced to confirm their orientation to the promoter and to ensure they contained uninterrupted open reading frames. Recombinant baculoviruses were constructed by transfection in Sf9 cells. Three recombinant baculoviruses were produced and contained the USA08MD34p-VP3, USA08MD34p-pVP2, or Mo195-pVP2 genomic sequences. Virus-like particles (VLPs) were observed with the use of transmission electron microscopy when the USA08MD34p-VP3 baculovirus was co-inoculated into Sf9 cells with either of the pVP2 constructs. VLPs were also observed when the USA08MD34p-pVP2 and Mo195-pVP2 were coexpressed with USA08MD34p-VP3. These multivalent VLPs contained both classic and variant pVP2 molecules. Stability tests demonstrated the VLPs were stable at 4 and 24 C for 8 wk. The USA08MD34p, Mo195, and multivalent VLPs were used to vaccinate chickens. They induced an IBDV-specific antibody response that was detected by enzyme-linked immunosorbent assay (ELISA), and virus-neutralizing antibodies were detected in vitro. Chickens vaccinated with the multivalent VLPs were protected from a virulent variant IBDV strain (V1) and a virulent classic IBDV strain (STC). The results indicate the multivalent VLPs maintained the antigenic integrity of the variant and classic viruses and have the potential to serve as a multivalent vaccine for use in breeder-flock vaccination programs. PMID:23678728

  2. Kinetics and mechanisms of crystal growth inhibition of indomethacin by model precipitation inhibitors

    NASA Astrophysics Data System (ADS)

    Patel, Dhaval

    Supersaturating Drug Delivery Systems (SDDS) could enhance oral bioavailability of poorly water soluble drugs (PWSD). Precipitation inhibitors (PIs) in SDDS could maintain supersaturation by inhibiting nucleation, crystal growth, or both. The mechanisms by which these effects are realized are generally unknown. The goal of this dissertation was to explore the mechanisms underpinning the effects of model PIs including hydroxypropyl beta-cyclodextrins (HP-beta-CD), hydroxypropyl methylcellulose (HPMC), and polyvinylpyrrolidone (PVP) on the crystal growth of indomethacin, a model PWSD. At high degrees of supersaturation (S), the crystal growth kinetics of indomethacin was bulk diffusion-controlled, which was attributed to a high energy form deposited on the seed crystals. At lower S, indomethacin growth kinetics was surface integration-controlled. The effect of HP-beta-CD at high S was successfully modeled using the reactive diffusion layer theory. The superior effects of PVP and HPMC as compared to HP-beta-CD at high S were attributed to a change in the rate limiting step from bulk diffusion to surface integration largely due to prevention of the high energy form formation. The effects of PIs at low S were attributed to significant retardation of the surface integration rate, a phenomenon that may reflect the adsorption of PIs onto the growing surface. PVP was selected to further understand the relationship between adsorption and crystal growth inhibition. The Langmuir adsorption isotherm model fit the adsorption isotherms of PVP and N-vinylpyrrolidone well. The affinity and extent of adsorption of PVP were significantly higher than those of N-vinylpyrrolidone, which was attributed to cooperative interactions between PVP and indomethacin. The extent of PVP adsorption on a weight-basis was greater for higher molecular weight PVP but less on a molar-basis indicating an increased percentage of loops and tails for higher molecular weight PVPs. PVP significantly inhibited

  3. In vivo potency and efficacy of the novel cathinone α-pyrrolidinopentiophenone and 3,4-methylenedioxypyrovalerone: Self-administration and locomotor stimulation in male rats

    PubMed Central

    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

  4. Comparative Effectiveness of Dialyzers: A Longitudinal, Propensity Score-Matched Study of Incident Hemodialysis Patients

    PubMed Central

    Hunt, Abigail; Laplante, Suzanne; Beck, Werner; Gellens, Mary; Brunelli, Steven M.

    2016-01-01

    Differences in dialyzer design may have consequences for patient outcomes. We evaluated the comparative effectiveness of commonly used dialyzers with respect to measures of dialysis treatment, anemia management, inflammation, and dialyzer clotting. Patients receiving hemodialysis between January 1, 2009, and December 31, 2013, and using polyarylethersulfone–polyvinylpyrrolidone (PAS-PVP; Polyflux Revaclear) or polysulfone (PS; Optiflux 160 or Optiflux 180) dialyzers were followed for 1 year or until end of study or censoring for dialyzer switch, modality change, or loss to follow-up. For each comparison, eligible patients were propensity score-matched 1:1 on a range of baseline characteristics. Outcomes were assessed using generalized linear mixed models. Dialysis adequacy was similar in both dialyzer groups. Erythropoiesis-stimulating agent (ESA) doses were lower for patients using PAS-PVP versus patients using PS-160 (difference range: 75–589 units/treatment; statistically significant in months 1–5 and 7) and for patients using PAS-PVP versus patients using PS-180 (difference range: 27–591 unit/treatment; statistically significant in months 1–9). Intravenous iron doses trended lower for patients using PAS-PVP versus patients using PS, but hemoglobin concentrations were equivalent. In conclusion, use of PAS-PVP versus PS dialyzers was associated with equivalent dialysis adequacy, lower ESA doses, modestly lower Intravenous iron doses, and equivalent hemoglobin concentrations. PMID:27442860

  5. In vitro antiseptic susceptibility of clinical isolates from nosocomial infections.

    PubMed

    Shimizu, M; Okuzumi, K; Yoneyama, A; Kunisada, T; Araake, M; Ogawa, H; Kimura, S

    2002-01-01

    To evaluate the susceptibility of a large number of strains to various antiseptics, we elaborated a simple, qualitative broth turbidity method in which we could quickly judge the efficacy visually. For this method, we prepared a modified neutralizer broth, consisting of trypticase soy broth containing 15% Tween 80, 1% soybean lecithin and 0.5% sodium thiosulfate. The susceptibilities of Serratia marcescens No. 26 to 4 antiseptics obtained from the turbidity method showed a good agreement with those obtained from the colony-counting method; the 4 antiseptics tested were povidone-iodine (PVP-I), chlorhexidine gluconate (CHG), benzalkonium chloride (BAC) and alkyldiaminoethylglycine hydrochloride (AEG). Both PVP-I and BAC had complete efficacy in 0.5 min against all isolates tested [100 isolates of S. marcescens, 103 of Klebsiella pneumoniae, 99 of Pseudomonas aeruginosa, 19 of Alcaligenes faecalis and 30 of A. xylosoxidans subsp. xylosoxydans (A. xylosoxydans)]. In contrast, the effectiveness of CHG was weak compared with PVP-I, BAC and AEG. Strong resistance against AEG was noted even after 3-min exposure in 1 isolate each of A. faecalis and A. xylosoxydans. It is concluded that the turbidity test is a simple and accurate method to evaluate susceptibility to various antiseptics and that it is suitable for a screening of a large number of strains. Among the 4 antiseptics tested, PVP-I and BAC showed a consistently high activity against all isolates, confirming PVP-I and BAC to be clinically useful antiseptics. PMID:12011516

  6. Initial Experiences with a 980 nm Diode Laser for Photoselective Vaporization of the Prostate for the Treatment of Benign Prostatic Hyperplasia

    PubMed Central

    Yang, Ki Su; Kim, In Gon; Han, Bo Hyun; Kong, Geun Soo

    2011-01-01

    Purpose This study was conducted to analyze the efficacy of photoselective vaporization of the prostate (PVP) with the use of a 980 nm diode laser for benign prostatic hyperplasia (BPH) according to postoperative period. Materials and Methods Data were collected from 96 patients who were diagnosed with BPH and who underwent PVP with the 980 nm K2 diode laser. Postoperative parameters, including International Prostate Symptom Score (IPSS), quality of life (QoL) score, maximum urinary flow rate (Qmax), and post-void residual volume (PVR), were assessed and compared with preoperative baseline values. Results The mean prostate volume was 45.3±15.6 g, the mean operative time (lasing time) was 22.9±18.3 minutes, the total amount of energy was 126±84 kJ, and the Foley catheter maintenance period after PVP was 24.8±5.6 hours. At 1 month, significant improvements were noted in IPSS (11.7±6.6), QoL score (2.3±1.1), Qmax (12.7±6.1 ml/sec), and PVR (41.9±30.5 ml). After 3 months, all follow-up parameters showed significant improvements that were sustained throughout a period of 6 months after PVP. Conclusions PVP using a K2 diode laser is a minimally invasive and effective surgical method for improvement of BPH and is associated with minimal morbidity. PMID:22195264

  7. Development and Evaluation of Mouth Dissolving Films of Amlodipine Besylate for Enhanced Therapeutic Efficacy.

    PubMed

    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. PMID:26556197

  8. Physicochemical characterisation and biological evaluation of polyvinylpyrrolidone-iodine engineered polyurethane (Tecoflex(®)).

    PubMed

    Khandwekar, Anand P; Doble, Mukesh

    2011-05-01

    Bacterial adhesion and encrustation are the known causes for obstruction or blockage of urethral catheters and ureteral stents, which often hinders their effective use within the urinary tract. In this in vitro study, polyvinylpyrrolidone-iodine (PVP-I) complex modified polyurethane (Tecoflex(®)) systems were created by physically entrapping the modifying species during the reversible swelling of the polymer surface region. The presence of the PVP-I molecules on this surfaces were verified by ATR-FTIR, AFM and SEM-EDAX analysis, while wettability of the films was investigated by water contact angle measurements. The modified surfaces were investigated for its suitability as a urinary tract biomaterial by comparing its lubricity and ability to resist bacterial adherence and encrustation with that of base polyurethane. The PVP-I modified polyurethane showed a nanopatterned surface topography and was highly hydrophilic and more lubricious than control polyurethane. Adherence of both the gram positive Staphylococcus aureus (by 86%; **P < 0.01) and gram-negative Pseudomonas aeruginosa (by 80%; *P < 0.05) was significantly reduced on the modified surfaces. The deposition of struvite and hydroxyapatite the major components of urinary tract encrustations were significantly less on PVP-I modified polyurethane as compared to base polyurethane, especially reduction in hydroxyapatite encrustation was particularly marked. These results demonstrated that the PVP-I entrapment process can be applied on polyurethane in order to reduce/lower complications associated with bacterial adhesion and deposition of encrustation on polyurethanes. PMID:21437640

  9. Polyvinylpyrrolidone as binder for castable supercapacitor electrodes with high electrochemical performance in organic electrolytes

    NASA Astrophysics Data System (ADS)

    Aslan, M.; Weingarth, D.; Jäckel, N.; Atchison, J. S.; Grobelsek, I.; Presser, V.

    2014-11-01

    Polyvinylpyrrolidone (PVP) is presented as a "greener" alternative to commonly used supercapacitor binders, namely polyvinylidenedifluoride (PVDF) or polytetrafluoroethylene (PTFE). The key advantages of using PVP are that it is non-toxic and soluble in ethanol and it can be used to spray coat or drain cast activated carbon (AC) electrodes directly on a current collector such as aluminum foil - in contrast to PTFE that requires rolling or PVDF that requires toxic N-methylpyrrolidone (NMP). The electrodes with the best mechanical stability incorporated 3.5 mass% of 1.300.000 g mol-1 PVP. Compared to PTFE or PVDF, the resulting pore volume was significantly higher and the specific surface area significantly larger when using PVP (normalized to the amount of AC). A good electrochemical performance was observed in organic electrolytes for AC-PVP electrodes: 112 or 97 F g-1 at 0.1 A g-1 in 1 M TEA-BF4 in propylene carbonate or acetonitrile, respectively. The performance stability was comparable to PTFE-bound electrodes when adjusting the maximum cell voltage to 2.5 V while preserving the manufacturing features of PVDF-AC films. (Electro)chemical stability is shown by electrochemical testing and infrared vibrational spectroscopy for propylene carbonate and acetonitrile.

  10. Hydrogen peroxide and glucose biosensor based on silver nanowires synthesized by polyol process.

    PubMed

    Yang, Xuejuan; Bai, Jing; Wang, Yinhu; Jiang, Xiue; He, Xiaoying

    2012-09-21

    Silver nanowires synthesized through a polyol process using polyvinylpyrrolidone as protection (PVP-AgNWs) were used as a new electrode material for constructing a sensor. Hydrogen peroxide (H(2)O(2)) and glucose were used as analytes to demonstrate the sensor performance of the PVP-AgNWs. It is found that the PVP-AgNWs-modified glassy carbon electrode (PVP-AgNWs/GCE) exhibits remarkable catalytic performance toward H(2)O(2) reduction. This sensor has a fast amperometric response time of less than 2 s and the catalytic current is linear over the concentration of H(2)O(2) ranging from 20 μM to 3.62 mM (R = 0.998) with a detection limit of 2.3 μM estimated on a signal-to-noise ratio of 3. A glucose biosensor was constructed by immobilizing glucose oxidase (GOD) onto the surface of the PVP-AgNWs/GCE. The resultant glucose biosensor can be used for glucose detection in human blood serum with a sensitivity of 15.86 μA mM(-1) cm(-2) and good selectivity and stability. PMID:22858619

  11. Radiation-induced synthesis of nanogels based on poly(N-vinyl-2-pyrrolidone)-A review

    NASA Astrophysics Data System (ADS)

    Kadlubowski, Slawomir

    2014-09-01

    Nanogels are nanometer-scale two-component systems consisting of a permanent three-dimensional network of linked polymer chains, and molecules of a solvent filling the pores of this network. A number of synthetic routes have been developed for nanogels. One of them is based on intramolecular cross-linking of individual polymer chains and ionizing radiation is a suitable tool for initiation of this process. Poly(N-vinyl-2-pyrrolidone)-PVP-was one of the first polymers used to obtain intramolecularly cross-linked macromolecules using this method called preparative pulse radiolysis. This review summarizes radiation-based techniques used for synthesis of PVP-derived nanogels starting from preparative pulse radiolysis, through irradiation of thermally collapsed PVP and cross-linking in microemulsion up to formation of PVP based interpolymer complexes. In addition, possible practical applications of PVP-based nanogels have been presented mainly in the biomedical field. Nanogels functionalized with (3-N-aminopropyl)methacrylamide hydrochloride may serve for bioconjugation and drug transportation into the cells. Nanogels of interpolymer complexes are expected to be mucoadhesive and be able to bind cationic drugs electrostatically and non-polar drugs via solubilization in the hydrophobic cores.

  12. Formation of core-shell-structured Zn2SnO4-carbon microspheres with superior electrochemical properties by one-pot spray pyrolysis.

    PubMed

    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). PMID:25429709

  13. Comparative Effectiveness of Dialyzers: A Longitudinal, Propensity Score-Matched Study of Incident Hemodialysis Patients.

    PubMed

    Sibbel, Scott; Hunt, Abigail; Laplante, Suzanne; Beck, Werner; Gellens, Mary; Brunelli, Steven M

    2016-01-01

    Differences in dialyzer design may have consequences for patient outcomes. We evaluated the comparative effectiveness of commonly used dialyzers with respect to measures of dialysis treatment, anemia management, inflammation, and dialyzer clotting. Patients receiving hemodialysis between January 1, 2009, and December 31, 2013, and using polyarylethersulfone-polyvinylpyrrolidone (PAS-PVP; Polyflux Revaclear) or polysulfone (PS; Optiflux 160 or Optiflux 180) dialyzers were followed for 1 year or until end of study or censoring for dialyzer switch, modality change, or loss to follow-up. For each comparison, eligible patients were propensity score-matched 1:1 on a range of baseline characteristics. Outcomes were assessed using generalized linear mixed models. Dialysis adequacy was similar in both dialyzer groups. Erythropoiesis-stimulating agent (ESA) doses were lower for patients using PAS-PVP versus patients using PS-160 (difference range: 75-589 units/treatment; statistically significant in months 1-5 and 7) and for patients using PAS-PVP versus patients using PS-180 (difference range: 27-591 unit/treatment; statistically significant in months 1-9). Intravenous iron doses trended lower for patients using PAS-PVP versus patients using PS, but hemoglobin concentrations were equivalent. In conclusion, use of PAS-PVP versus PS dialyzers was associated with equivalent dialysis adequacy, lower ESA doses, modestly lower Intravenous iron doses, and equivalent hemoglobin concentrations. PMID:27442860

  14. Synergy Between Polyvinylpyrrolidone-Coated Silver Nanoparticles and Azole Antifungal Against Drug-Resistant Candida albicans.

    PubMed

    Sun, Lingmei; Liao, Kai; Li, Yiping; Zhao, Lei; Liang, Sai; Guo, Dan; Hu, Jun; Wang, Dayong

    2016-03-01

    In the clinical practice, resistance of Candida albicans to antifungal agents has frequently emerged. Silver-nanoparticles (Ag-NPs) have been demonstrated to have the antifungal property. We investigated the potential for synergy between polyvinylpyrrolidone (PVP)-coated Ag-NPs and azole antifungal, such as fluconazole or voriconazole, against drug-resistant C. albicans strain CA10. When antifungal agent was examined alone, fluconazole and voriconazole did not kill drug-resistant C. albicans, and PVP-coated Ag-NPs had only the moderate killing ability. In contrast, the combinational treatment of PVP-coated Ag-NPs with fluconazole or voriconazole was effective in being against the drug-resistant C. albicans. After the combinational treatment, we detected the disruption of cell membrane integrity, the tendency of PVP-coated Ag-NPs to adhere to cell membrane, and the inhibition of budding process. Moreover, after the combinational treatment, the defects in ergosterol signaling and efflux pump functions were detected. Our results suggest that the combinational use of engineered nanomaterials (ENMs), such as PVP-coated Ag-NPs, with the conventional antifungal may be a viable strategy to combat drug-resistant fungal infection. PMID:27455637

  15. Small-angle neutron scattering study of the short-range organization of dispersed CsNi[Cr(CN)6] nanoparticles

    NASA Astrophysics Data System (ADS)

    Ridier, Karl; Gillon, Béatrice; André, Gilles; Chaboussant, Grégory; Catala, Laure; Mazérat, Sandra; Mallah, Talal

    2015-09-01

    Prussian blue analogues magnetic nanoparticles (of radius R0 = 2.4-8.6 nm) embedded in PVP (polyvinylpyrrolidone) or CTA+ (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* ≈ 3R0, corresponding to an effective repulsive interaction radius, is evidenced in PVP samples. In CTA+, electrostatic interactions play a crucial role and lead to a dense layer of CTA+ around the nanoparticles, which considerably alter the SANS patterns as compared to PVP. The SANS data of nanoparticles in CTA+ are best described by a core-shell model without visible inter-particle structure factor.

  16. Small-angle neutron scattering study of the short-range organization of dispersed CsNi[Cr(CN){sub 6}] nanoparticles

    SciTech Connect

    Ridier, Karl; Gillon, Béatrice; André, Gilles; Chaboussant, Grégory; Catala, Laure; Mazérat, Sandra; Mallah, Talal

    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.

  17. Nanoparticle cross-linked collagen shields for sustained delivery of pilocarpine hydrochloride.

    PubMed

    Agban, Yosra; Lian, Jiaxin; Prabakar, Sujay; Seyfoddin, Ali; Rupenthal, Ilva D

    2016-03-30

    Glaucoma is a common progressive eye disorder which remains the second leading cause of blindness worldwide. Current therapy involves frequent administration of eye drops which often results in poor patient adherence and therapeutic outcomes. The aim of this study was to overcome these limitations by developing a novel nanoparticle cross-linked collagen shield for sustained delivery of pilocarpine hydrochloride (PHCl). Three metal oxide nanoparticles (NPs); titanium dioxide (TiO2), zinc oxide (ZnO) and polyvinylpyrrolidone (PVP) capped zinc oxide (ZnO/PVP), were evaluated for their cytotoxicity as well as shield transparency before selecting ZnO/PVP NPs as the ideal candidate. Cross-linked collagen shields were then characterized for their mechanical strength, swelling capacity and bioadhesive properties, with ZnO/PVP NP cross-linked shields showing the most favorable characteristics compared to plain films. The shield with the best properties was then loaded with PHCl and in vitro release of zinc ions as well as PHCl was measured without and with further cross-linking by ultraviolet irradiation. The concentration of zinc ions released was well below the IC50 rendering them safe for ocular use. Moreover, collagen shields cross-linked with ZnO/PVP NPs released PHCl over a period of 14 days offering a promising sustained release treatment option for glaucoma. PMID:26828672

  18. Relationship between Personality Disorder Functioning Styles and the Emotional States in Bipolar I and II Disorders

    PubMed Central

    Yao, Jiashu; Xu, You; Qin, Yanhua; Liu, Jing; Shen, Yuedi; Wang, Wei; Chen, Wei

    2015-01-01

    Background 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. Methods 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. Results 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, Dependant, Paranoid (-) and Schizoid (-) predicted PVP; Borderline predicted MDQ; Passive-Aggressive and Schizoid (-) predicted HCL-32. In controls, Borderline and Narcissistic (-) predicted PVP; Borderline and Dependant (-) predicted MDQ. Conclusion 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. PMID:25625553

  19. Influence of the surface properties of polymeric insulators on the electrical stability of 6,13-bis(triisopropylsilylethynyl)-pentacene thin-film transistors

    NASA Astrophysics Data System (ADS)

    Baang, Sungkeun; Lee, Hyeonju; Ham, Youngjin; Zhang, Xue; Park, Jaehoon; Lee, Ho Won; Kim, Young Kwan; Piao, Shang Hao; Choi, Hyoung Jin

    2015-12-01

    We investigated the electrical stabilities of 6,13-bis(triisopropylsilylethynyl)-pentacene (TIPS-pentacene) thin-film transistors (TFTs) fabricated with cross-linked polymeric insulators, i.e., poly(4-vinylphenol) (PVP) and poly(4-vinylphenol-co-methyl methacrylate) (PVP- co-PMMA). Compared to the cross-linked PVP insulator, the TIPS-pentacene TFTs containing a cross-linked PVP- co-PMMA insulator exhibit less hysteresis upon reversal of the gate-voltage sweep direction and a lower shift in the threshold voltage during consecutive operations, which is ascribed to the relatively hydrophobic surface of the cross-linked PVP- co-PMMA insulator. When these polymer solutions are mixed with yttrium-oxide nanoparticles, the rough surfaces of both nanocomposite insulators lead to larger shifts in the threshold voltage during consecutive operations, but its effect on the hysteretic behavior in the transfer characteristics of the TIPS-pentacene TFTs is negligible. Thus, the influence of the surface properties of the polymeric insulators on the electrical stability of TIPS-pentacene TFTs can be explained through hole-trapping and the delayed-depletion of the holes at the insulator/semiconductor interface.

  20. Development and Evaluation of Mouth Dissolving Films of Amlodipine Besylate for Enhanced Therapeutic Efficacy

    PubMed Central

    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. PMID:26556197

  1. Preparation of desiccation-resistant aquatic-living Nostoc flagelliforme (Cyanophyceae) for potential ecological application

    PubMed Central

    Gao, Xiang; Yang, Yi-Wen; Cui, Li-Juan; Zhou, De-Bao; Qiu, Bao-Sheng

    2015-01-01

    Nostoc flagelliforme is a terrestrial edible cyanobacterium that grows in arid and semi-arid steppes. The continued over-exploitation in the last century has led to a sharp decline of this resource and a severe deterioration of the steppe ecology. Liquid-cultured N. flagelliforme serves as promising algal ‘seeds’ for resource restoration. In this study, macroscopic (or visible) aquatic-living colonies (MaACs) of N. flagelliforme were developed under weak light and high nitrogen conditions. In a 24 day shake-flask culture, MaACs were propagated by about 4.5-fold in biomass without loss of their macro-morphology; at the same time, the addition of weak UV-B treatment resulted in slightly bigger MaACs. Polyvinylpyrrolidone (PVP) k30, a water-soluble polymer, was used to generate the coating around MaACs, and after full desiccation, the coated MaACs could recover their photosynthetic physiological activity when rehydrated, with 4% PVP k30 for coating being most effective. In contrast, PVP k30-coated microscopic aquatic-living colonies of N. flagelliforme and non-coated MaACs showed no resistance to full desiccation. The macroscopic morphology or structure of MaACs should be crucial for the formation of protection by PVP k30 coating. PVP k30-coated MaACs were more approaching to actual application for resource restoration. PMID:25847617

  2. Effect of hydration on plasma vasopressin, renin, and aldosterone responses to head-up tilt

    NASA Technical Reports Server (NTRS)

    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.

  3. New platforms for multi-functional ocular lenses: engineering double-sided functionalized nano-coatings.

    PubMed

    Mehta, Prina; Justo, Lucas; Walsh, Susannah; Arshad, Muhammad S; Wilson, Clive G; O'Sullivan, Ciara K; Moghimi, Seyed M; Vizirianakis, Ioannis S; Avgoustakis, Konstantinos; Fatouros, Dimitris G; Ahmad, Zeeshan

    2015-05-01

    A scalable platform to prepare multi-functional ocular lenses is demonstrated. Using rapidly dissolving polyvinylpyrrolidone (PVP) as the active stabilizing matrix, both sides of ocular lenses were coated using a modified scaled-up masking electrohydrodynamic atomization (EHDA) technique (flow rates variable between 5 and 10 µL/min, applied voltage 4-11 kV). Each side was coated (using a specially designed flip-able well) selectively with a pre-determined morphology and model drug substance. PVP nanoparticles (inner side, to be in contact with the cornea, mean size PVP nanofibres (outer side, to be exposed to air and eye lid, mean width size PVP). Release of the probe and anti-microbial activity (using Staphylococcus aureus NCTC 6571) were demonstrated based on rapid dissolution and contact of PVP model substance matrix. Adapting these findings further for advanced EHDA technologies (encapsulation layering, controllable size and deposition and multi-phase media deposition options) and intrinsic material properties (functional polymers/excipients and advanced controlled release strategies) suggests several therapeutic platforms for ocular lenses can be further developed at ambient temperature and pressure. These provide multi-functional properties (in personalized delivery, nanomedicine and nanosensors) from a single drug delivery device. PMID:25582133

  4. Effect of Tannin-Binding Agents (Polyethylene Glycol and Polyvinylpyrrolidone) Supplementation on In Vitro Gas Production Kinetics of Some Grape Yield Byproducts

    PubMed Central

    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. PMID:23738107

  5. Effects of silver sulfide nanomaterials on mycorrhizal colonization of tomato plants and soil microbial communities in biosolid-amended soil.

    PubMed

    Judy, Jonathan D; Kirby, Jason K; Creamer, Courtney; McLaughlin, Mike J; Fiebiger, Cathy; Wright, Claire; Cavagnaro, Timothy R; Bertsch, Paul M

    2015-11-01

    We investigated effects of Ag2S engineered nanomaterials (ENMs), polyvinylpyrrolidone (PVP) coated Ag ENMs (PVP-Ag), and Ag(+) on arbuscular mycorrhizal fungi (AMF), their colonization of tomato (Solanum lycopersicum), and overall microbial community structure in biosolids-amended soil. Concentration-dependent uptake was measured in all treatments. Plants exposed to 100 mg kg(-1) PVP-Ag ENMs and 100 mg kg(-1) Ag(+) exhibited reduced biomass and greatly reduced mycorrhizal colonization. Bacteria, actinomycetes and fungi were inhibited by all treatment classes, with the largest reductions measured in 100 mg kg(-1) PVP-Ag ENMs and 100 mg kg(-1) Ag(+). Overall, Ag2S ENMs were less toxic to plants, less disruptive to plant-mycorrhizal symbiosis, and less inhibitory to the soil microbial community than PVP-Ag ENMs or Ag(+). However, significant effects were observed at 1 mg kg(-1) Ag2S ENMs, suggesting that the potential exists for microbial communities and the ecosystem services they provide to be disrupted by environmentally relevant concentrations of Ag2S ENMs. PMID:26196315

  6. Antibacterial effects of the povidone-iodine vacuum impregnation technique in expanded polytetrafluoroethylene augmentation rhinoplasty.

    PubMed

    Lee, Jung Min; Lee, Joong Seob; Kim, Dong-Kyu; Lee, Jun Ho; Park, Hae Sang; Lee, Ho Jun; Bae, Sung Hee; Jang, Ji Su; Lee, Jae Jun; Park, Chan Hum

    2016-06-01

    Expanded polytetrafluoroethylene (e-PTFE) is a popular graft material for augmentation rhinoplasty. Gore-Tex and Surgiform are two types of e-PTFE; Surgiform has thicker fibrils and is more compact than Gore-Tex. We conducted an ex vivo study to evaluate the ability of povidone-iodine (PVP-I) vacuum pretreatment to prevent infection with these two types of e-PTFE. Gore-Tex and Surgiform specimens were cut into 2-mm(3) pieces, which were separated into two groups. One group for each e-PTFE was disinfected with vacuum PVP-I impregnation and the other group was not disinfected. Using the pieces of implant material, swabs were obtained from the nasal cavities of 20 healthy adults, and the specimens were incubated on agar plates and viewed by scanning electron microscopy (SEM). We found that PVP-I treatment significantly reduced the bacterial colony counts in both the Gore-Tex and Surgiform groups. In the SEM images, bacterial colonies were observed both inside and outside the untreated Gore-Tex; on the untreated Surgiform, they were found primarily on the surface. Few bacteria were detected in the PVP-I-treated Gore-Tex and Surgiform groups. Our findings suggest that PVP-I pretreatment can reduce the risk of infection associated with e-PTFE. PMID:27304448

  7. Influence of natural organic matter on transport and retention of polymer coated silver nanoparticles in porous media.

    PubMed

    Yang, Xinyao; Lin, Shihong; Wiesner, Mark R

    2014-01-15

    Interactions between organic matter (OM) and engineered polymer coatings as they affect the retention of polyvinylpyrrolidone (PVP) polymer-coated silver nanoparticles (AgNPs) were studied. Two distinct types of OM-cysteine representing low molecular weight multivalent functional groups, and Suwannee River Humic Acid (HA) representing high molecular weight polymers, were investigated with respect to their effects on particle stability in aggregation and deposition. Aggregation of the PVP coated AgNPs (PVP-AgNPs) was enhanced by cysteine addition at high ionic strengths, which was attributed to cysteine binding to the AgNPs and replacing the otherwise steric stabilizing agent PVP. In contrast the addition of HA did not increase aggregation rates and decreased PVP-AgNP deposition to the silica porous medium, consistent with enhanced electrosteric stabilization by the HA. Although cysteine also reduced deposition in the porous medium, the mechanisms of reduced deposition appear to be enhanced electric double layer (EDL) interaction at low ionic strengths. At higher ionic strengths, aggregation was favored leading to lower deposition due to smaller diffusion coefficients and single collector efficiencies despite the reduced EDL interactions. PMID:24295767

  8. In-situ formation of silver nanoparticles on poly (lactic acid) film by γ-radiation induced grafting of N-vinyl pyrrolidone.

    PubMed

    Wang, Jingxia; Chen, Hao; Chen, Zhuping; Chen, Yuheng; Guo, Dan; Ni, Maojun; Liu, Siyang; Peng, Chaorong

    2016-06-01

    A fast, easy and novel method for preparing biodegradable polymer films with silver nanoparticles was investigated to endow the material with excellent biocompatibility and antibacterial property. Silver nanoparticles (Ag NPs) were immobilized on the surface of polylactic acid (PLA) film by gamma radiation induced grafting of N-vinyl pyrrolidone (NVP). In this method, poly (N-vinyl pyrrolidone) (PVP) was produced and grafted onto the surface of PLA film by gamma radiation polymerization of NVP. PVP acted as both a bridge to connect the Ag NPs with the PLA film, and a stabilizer to protect the Ag NPs from agglomeration. The effect of various reaction parameters, including NVP/Ag mole ratio and radiation dose, on the fabrication of PLA-g-NVP/Ag film was demonstrated. Moreover, the interaction between PVP and Ag NPs was studied by X-ray photoelectron spectroscopy and Fourier-transform infrared spectroscopy, that revealed the Ag NPs coordinated through the oxygen atom on the carbonyl group of PVP at 15kGy radiation dose, but through the nitrogen atom and the oxygen atom of the amide group of PVP at 1kGy dose. PMID:27040205

  9. Synthesis and Characterization of Polyvinylpyrrolidone Silica Core-Shell Nanocomposite Particles.

    PubMed

    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. PMID:26413650

  10. Enhanced Cyclability of Li/Polysulfide Batteries by a Polymer-Modified Carbon Paper Current Collector.

    PubMed

    Cui, Yi; Fu, Yongzhu

    2015-09-16

    Lithium-sulfur (Li-S) batteries are considered to be the next-generation rechargeable systems due to their high energy densities and low cost. However, significant capacity decay over cycling is a major impediment for their practical applications. Polysulfides Li2Sx (3PVP) current collector in Li/polysulfide cells. PVP is soluble in the electrolyte solvent, but shows strong affinity with lithium polysulfides. The retention of polysulfides in the CP-PVP current collector is improved by ∼50%, which is measured by a linear sweep voltammetry method. Without LiNO3 additive in the electrolyte, the CP-PVP current collector with 50 μg of PVP can significantly improve cycling stability with a capacity retention of >90% over 50 cycles at C/10 rate. With LiNO3 additive in the electrolyte, the cell shows a reversible capacity of >1000 mAh g(-1) and a capacity retention of >80% over 100 cycles at C/5 rate. PMID:26305234

  11. Bioavailability of a new oral formulation of medroxyprogesterone acetate compared with the standard formulation: a single dose randomized study.

    PubMed

    Kjaer, M; Brunsgaard, N; Jakobsen, P; Edwards, D M; Strolin-Benedetti, M

    1993-08-01

    Twenty-six female patients with breast cancer participated in an open, randomized, cross-over study comparing single dose bioavailability of a recently developed oral medroxyprogesterone acetate (MPA) formulation (200 mg sachet where MPA is loaded in a polyvinylpyrrolidone cross-linked polymer, MPA/PVP) with the standard formulation (500 mg tablet). Blood tests were performed under standardized conditions for 120 h in all patients and MPA plasma concentrations determined by means of HPLC. Dose-normalized AUC(0-tz), AUC (0-infinity) and Cmax were all significantly higher for the MPA/PVP formulation than for the standard formulation. The relative bioavailability of the MPA/PVP formulation was on average three times superior to that of the standard formulation. This new MPA formulation might have important clinical implications for the treatment of hormone-sensitive cancer. PMID:8400345

  12. Effect of a weak magnetic field on the Mizoroki-Heck coupling reaction in the presence of wicker-like palladium-poly(N-vinylpyrrolidone)-iron nanocatalyst

    NASA Astrophysics Data System (ADS)

    Rafiee, Ezzat; Joshaghani, Mohammad; Abadi, Parvaneh Ghaderi-Shekhi

    2016-06-01

    The wicker-like Pd-PVP-Fe (palladium-poly(N-vinylpyrrolidone)-iron) was synthesized by the external magnetic field (EMF). The Pd-based catalyst with nano and the face-centered cubic (fcc) structure was obtained at room temperature without using any additive. The resulting composite was characterized. The results show that EMF has a great influence on morphology, particle size, and crystalline structure of the Pd-PVP-Fe composite. The resulting composite (Pd-PVP-Fe), was found to be an effective catalyst for the Mizoroki-Heck reaction while is exposed to EMF with the intensity at 486 μT. The reused catalyst for at least five repeating cycles, shows excellent activity.

  13. Preparation of silver-coated glass frit and its application in silicon solar cells

    NASA Astrophysics Data System (ADS)

    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.

  14. Large-scale and highly efficient synthesis of micro- and nano-fibers with controlled fiber morphology by centrifugal jet spinning for tissue regeneration

    NASA Astrophysics Data System (ADS)

    Ren, Liyun; Pandit, Vaibhav; Elkin, Joshua; Denman, Tyler; Cooper, James A.; Kotha, Shiva P.

    2013-02-01

    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 study the tissue regeneration efficacy of the engineered PLLA fiber matrix, human dermal fibroblasts are used to simulate partial skin graft. Fibers with increased PLLA surface roughness and porosity demonstrated a trend towards higher cell attachment and proliferation.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

  15. Preparation by coaxial electrospinning and characterization of membranes releasing (-) epicatechin as scaffold for tissue engineering.

    PubMed

    Castillo-Ortega, M M; Montaño-Figueroa, A G; Rodríguez-Félix, D E; Prado-Villegas, G; Pino-Ocaño, K P; Valencia-Córdova, M J; Quiroz-Castillo, J M; Herrera-Franco, P J

    2015-01-01

    Optimal conditions for the preparation of a composite material of fibers of cellulose acetate (CA) and poly(vinyl pyrrolidone) (PVP), containing epicatechin (Epic) within the fiber CA/PVP-Epic/CA, were found. The morphology and physical/chemical properties of the fibrous membranes containing CA, PVP, and epicatechin were characterized using FTIR spectroscopy, thermal analysis, SEM, TEM, and natural weathering. Also, mechanical characterization of the fibers showed that tensile strength of the membrane was not affected by the presence of epicatechin within the fiber as compared with fibers without epicatechin. The effect of the medium on the release rate of epicatechin was also studied. The amount of epicatechin release was higher in water, 79.6%, and 31% in MesenCult medium. These results showed that these composite materials are recommended for cardiac tissue engineering; furthermore, using these materials allows precise release of the epicatechin in the damaged tissue. PMID:25491975

  16. Fouling behaviour of membranes with different characteristics by urban wastewater secondary effluent.

    PubMed

    Meng, Xiaorong; Donghui, Fu; Chenguang, Gao; Lei, Wang; Weiting, Tang; Wang, Xudong

    2016-04-01

    Fouling behaviours and antifouling properties of polyvinylidene fluoride (PVDF) ultrafiltration membranes blending with polyvinyl alcohol (PVA), polyvinylpyrrolidone (PVP) and polymethyl methacrylate (PMMA) had been investigated using the secondary effluent as the filtration medium. The results demonstrated that the antifouling properties of membranes using PVA and PVP as the additives were generally stronger than those using PMMA. Additives PVA and PVP could effectively improve the structural property and hydrophilicity of the membrane and result in an outstanding antifouling property. A dense membrane surface could prevent low molecular foulants from entering into the membrane pores, depositing on the membrane with a loose spongy layer and penetrating into the internal macropore structure. The not fully generated internal macropores on the membrane surface were trend to be plugged, which resulted in serious flux decay and the membrane fouling was irreversible. Filtration cake formed on the membrane due to concentration polarization, which caused membrane flux decline and high flux recovery after cleaning. PMID:26370705

  17. Light Scattering Study on SWNTs Solutions

    NASA Astrophysics Data System (ADS)

    Wang, Tong; Liu, Tao; Veedu Sreekumar, T.; Kumar, Satish; Tannenbaum, Rina; Moore, Vallerie; Hauge, R. H.; Smalley, R. E.

    2003-03-01

    SWNT/Oleum dispersions are being used to form film and fibers showing high electrical conductivity. PVP wrapped SWNTs have also been dissolved in aqueous medium. Light scattering studies have been performed in this study to understand the nanotube dispersion on both SWNT/Oleum as well as PVP/SWNT/surfactant/water dispersions. Preliminary studies on PVP wrapped SWNTs/water and SWNTs/oleum dispersion system show the existence of a critical concentration (c*) of SWNTs. Below c*, the detected scattering intensity increases with concentration; and above c*, the detected scattering intensity decreases with concentration. This observed phenomenon is attributed to the competition of scattering and strong absorption of SWNTs to visible light. Based on this study, level of SWNT dispersion is being studied. Results of these studies will be reported.

  18. Selective hydrogenation of m-chloronitrobenzene to m-chloroaniline over polyvinylpyrrolidone-stabilized Pt and Pt/Sn catalysts

    NASA Astrophysics Data System (ADS)

    Li, Feng; Ma, Rui; Song, Hualin; Song, Hua; Yu, Dezhi

    2015-05-01

    A Pt-polyvinylpyrrolidone (PVP) catalyst was synthesized via chemical reduction of platinum ions with hydrazine hydrate in a PVP/ n-butanol/H2PtCl6 aqueous solution. Its catalytic activity was evaluated by the liquid-phase hydrogenation of m-chloronitrobenzene ( m-CNB) to m-chloroaniline ( m-CAN) under mild conditions ( T = 303 K, p = 0.1 MPa). The as prepared catalyst exhibited higher activity and selectivity than prepared via conventional ethanol reduction with the same platinum load. The catalytic performance of PVP-Pt catalyst was remarkably improved by addition of 0.2 wt % Sn4+. The modification mechanism may be related with the interaction of Sn4+ with nitro group of m-CNB and -NH2 in m-CAN.

  19. Evaluation of polyethylene oxide compacts as gastroretentive delivery systems.

    PubMed

    Mahalingam, Ravichandran; Jasti, Bhaskara; Birudaraj, Raj; Stefanidis, Dimitrios; Killion, Robert; Alfredson, Tom; Anne, Pratap; Li, Xiaoling

    2009-01-01

    Compacts containing selected bioadhesive polymers, fillers, and binders were investigated for their potential as a bioadhesive gastroretentive delivery system to deliver water soluble and water insoluble compounds in the stomach. Compacts with 90:10, 75:25, and 60:40 of polyvinylpyrrolidone (PVP) and polyethylene oxide (PEO) were evaluated for swelling, dissolution, bioadhesion, and in vitro gastric retention. Compacts containing higher PEO showed higher swelling (111.13%) and bioadhesion (0.62 +/- 0.03 N/cm(2)), and retained their integrity and adherence onto gastric mucosa for about 9 h under in vitro conditions. In vivo gastroretentive property of compacts were evaluated in Yorkshire cross swine. Compacts containing 58% PVP, 40% PEO and 2% of water soluble or water insoluble marker compounds showed gastroadhesive and retentive properties in vivo. It is concluded that PEO in combination with PVP yields a non disintegrating type bioadhesive dosage form which is suitable for gastroretentive applications. PMID:19148757

  20. Morphology Control of FeCo Alloy Particles Synthesized by Polyol Process

    SciTech Connect

    Kodama, D.; Sato, Y.; Tohji, K.; Jeyadevan, B.; Shinoda, K.; Sato, K.

    2007-03-20

    FeCo alloy is a soft magnetic material that possesses the highest saturation magnetization of 2.4 T and crystallizes in bcc structure as in the case of {alpha}-Fe. However, the particles synthesized were highly agglomerated. Thus, in this paper, an attempt was made to control the morphology of the particles using different types and concentrations of surfactants such as oleic acid, oleyl amine, polyvinylpyrrolidone (PVP), etc., during the synthesis of the particles. Though all the surfactant experimented partially prevented the agglomeration, products had larger size distribution except for PVP, which provided nearly monodispersed particles. Furthermore, the FeCo particles synthesized in the presence of PVP were either cubic or nearly spherical depending on the concentration of Fe.

  1. Room temperature optical and magnetic properties of polyvinylpyrrolidone capped ZnO nanoparticles

    SciTech Connect

    Chakrabarti, Mahuya; Chakrabarti, Keka R.; Sanyal, D.; Chakrabarti, A.

    2009-09-15

    Defect induced room temperature ferromagnetic properties of polyvinylpyrrolidone (PVP) capped nanocrystalline ZnO samples have been studied. Crystal phase and the lattice parameter of the synthesized nanocrystalline samples have been determined from X-ray diffraction spectra (XRD) and high-resolution transmission electron micrographs (HR-TEM). Room temperature photoluminescence (PL) spectrum for the bare ZnO sample shows a strong band at {approx} 379 nm and another band at {approx} 525 nm. The PL spectra also revealed that the number of oxygen vacancies in the uncapped sample is more than the PVP capped sample. Both sample exhibit ferromagnetic property at room temperature when annealed at 500 deg. C for 3 h, due to the formation of adequate oxygen vacancy related defects. The saturation magnetization for the annealed PVP capped sample is found to be larger compared to that for the uncapped sample.

  2. Synthesis, characterization and Monte Carlo simulation of CoFe2O4/Polyvinylpyrrolidone nanocomposites: The coercivity investigation

    NASA Astrophysics Data System (ADS)

    Mirzaee, Sh; Farjami shayesteh, S.; Mahdavifar, S.; Hekmatara, S. Hoda.

    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).

  3. Interaction of Se{sup 0} nanoparticles stabilized by poly(vinylpyrrolidone) with gel films of cellulose Acetobacter xylinum

    SciTech Connect

    Baklagina, Yu. G.; Khripunov, A. K.; Tkachenko, A. A.; Suvorova, E. I.; Klechkovskaya, V. V. Borovikova, L. N.; Smyslov, R. Yu.; Nilova, V. K.; Nazarkina, Ya. I.; Lavrent'ev, V. K.; Valueva, S. V.; Kipper, A. I.; Kopeikin, V. V.

    2006-07-15

    The sorption and desorption of poly(vinylpyrrolidone)-Se{sup 0} (PVP-Se{sup 0}) nanoparticles on gel films of cellulose Acetobacter xylinum (CAX) are investigated. It is revealed that the hydrodynamic radius R{sub h} of PVP-Se{sup 0} nanoparticles decreases from 57 nm in the initial solution (without CAX gel films) to 25 nm after the sorption of nanostructures on gel films and then increases to approximately 100 nm after the desorption of nanoparticles with water from dry samples of the CAX gel film-PVP-Se{sup 0} nanocomposite. It is found that selenium atoms do not penetrate into crystallites of the cellulose nanofibrils and replace water molecules sorbed by the primary hydroxyl groups of their walls. Poly(vinylpyrrolidone)-Se{sup 0} nanoclusters differ in the number and size upon their sorption inside the cellulose gel film and on the film surface.

  4. Comparative study of the effects of treatment with diethyleneiminebenzoquinone and its polymer complex with polyvinylpyrrolidone on the primary response of mice to sheep red blood cells.

    PubMed

    Kostadinov, D A; Popov, D V

    1978-05-01

    The primary response of BALB/c mice to sheep red blood cells was used to study comparatively the time-dependent effects of a 5-day course of treatment with equivalent doses (0.8 mg/kg of body weight every day) of the cytotoxic agent diethyleneiminebenzoquinone (DEiBq) and its polymer complex with polyvinylpyrrolidone (DEiBqPVP). The experimental results show that in contrast to treatment with DEiBq, the ability of treated mice to establish a specific immune response was not markedly impaired during the treatment with DEiBqPVP. The possible significance of these results is considered with reference to the use of the synthetic polymer PVP as a carrier of cytotoxic groups in experimental cancer chemotherapy. PMID:556384

  5. Percutaneous vertebroplasty for Langerhans cell histiocytosis of the lumbar spine in an adult: Case report and review of the literature

    PubMed Central

    FENG, FEI; TANG, HAI; CHEN, HAO; JIA, PU; BAO, LI; LI, JIN-JUN

    2013-01-01

    Langerhans cell histiocytosis (LCH) is extremely rare in the lumbar spine of adults. The radiological features typically manifest as vertebral tumors. The exact etiology of LCH remains unknown. Langerhans cells may cause local or systemic effects. The most frequent sites of these bony lesions are the skull, femur, mandible, pelvis and spine. To date, only 3 spinal LCH cases treated by percutaneous vertebroplasty (PVP) have been reported. The present study reports a case of LCH of the fourth lumbar vertebra (L4) in a 51-year-old male with a 10-day history of low back pain, limited waist motion and right lower limb numbness. The patient was treated using PVP. The use of PVP for treating LCH of the spine was successful. The present study provides an up-to-date literature overview of LCH. PMID:23251253

  6. Transforming powder mechanical properties by core/shell structure: compressible sand.

    PubMed

    Shi, Limin; Sun, Changquan Calvin

    2010-11-01

    Some active pharmaceutical ingredients possess poor mechanical properties and are not suitable for tableting. Using fine sand (silicon dioxide), we show that a core/shell structure, where a core particle (sand) is coated with a thin layer of polyvinylpyrrolidone (PVP), can profoundly improve powder compaction properties. Sand coated with 5% PVP could be compressed into intact tablets. Under a given compaction pressure, tablet tensile strength increases dramatically with the amount of coating. This is in sharp contrast to poor compaction properties of physical mixtures, where intact tablets cannot be made when PVP content is 20% or less. The profoundly improved tabletability of core/shell particles is attributed to the formation of a continuous three-dimensional bonding network in the tablet. PMID:20845444

  7. Spherically-clustered porous Au-Ag alloy nanoparticle prepared by partial inhibition of galvanic replacement and its application for efficient multimodal therapy.

    PubMed

    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. PMID:25560916

  8. Importance of Viscoelastic Property Measurement of a New Hydrogel for Health Care

    NASA Astrophysics Data System (ADS)

    Roy, Niladri; Saha, Nabanita; Kitano, Takeshi; Saha, Petr

    2009-07-01

    A simple technology based new hydrogel "PVP-CMC-BA" has been prepared by the scientists of Tomas Bata University in Zlin, Czech Republic. Its swelling property (in presence of water, human blood and different pH), antimicrobial property (in presence of skin infection causing agents like: Staphylococcus aureus; bacteria and Candida albicans; fungi) and viscoelastic properties such as storage modulus (G'), loss modulus (G") and complex viscosity (η*) were investigated at room temperature (25-28° C) which demonstrate that PVP-CMC-BA hydrogel is maintaining requisite properties for health care application, specially as a wound dressing material. The elasticity and antimicrobial property of PVP-CMC-BA is directly correlated with percentage of boric acid, an antiseptic agent. The consequential values of viscoelastic properties of the hydrogel (before drying) enable us to understand its specific flexible condition to apply on the surface of human body.

  9. Solid dispersion of quercetin in cellulose derivative matrices influences both solubility and stability.

    PubMed

    Li, Bin; Konecke, Stephanie; Harich, Kim; Wegiel, Lindsay; Taylor, Lynne S; Edgar, Kevin J

    2013-02-15

    Amorphous solid dispersions (ASD) of quercetin (Que) in cellulose derivative matrices, carboxymethylcellulose acetate butyrate (CMCAB), hydroxypropylmethylcellulose acetate succinate (HPMCAS), and cellulose acetate adipate propionate (CAAdP) were prepared with the goal of identifying an ASD that effectively increased Que aqueous solution concentration. Crystalline quercetin and Que/poly(vinylpyrrolidinone) (PVP) ASD were evaluated for comparison. Powder X-ray diffraction (XRPD) and differential scanning calorimetry (DSC) were used to examine the crystallinity of ASDs, physical mixtures (PM) and quercetin. ASDs were amorphous up to 50 wt% Que. Que stability against crystallization and solution concentrations from these ASDs were significantly higher than those observed for physical mixtures and crystalline Que. PVP stabilizes against both Que degradation and recrystallization; in contrast, these carboxylated cellulose derivatives inhibit recrystallization but release Que slowly. PVP ASDs afforded fast and complete drug release, while ASDs using these three cellulose derivatives provide slow, incomplete, pH-triggered drug release. PMID:23399255

  10. Blood pressure and plasma renin activity as predictors of orthostatic intolerance

    NASA Technical Reports Server (NTRS)

    Harrison, M. H.; Kravik, S. E.; Geelen, G.; Keil, L.; Greenleaf, J. E.

    1985-01-01

    The effect of 3 h standing, followed by a period of head-up tilt (HUT) on physiological response (orthostatic tolerance, blood pressure and heart rate), as well as on plasma vasopressin (PVP) and renin activity (PRA) were studied in 13 dehydrated (to 2.4 pct loss of body weight) subjects. Seven subjects showed signs of orthostatic intolerance (INT), manifested by sweating, pallor, nausea and dizziness. Prior to these symptoms, the INT subjects exhibited lower systolic (SP) and pulse (PP) pressures, and an elevated PRA, compared to the tolerant (TOL) subjects. HUT has aggravated increases of RPA in the INT subjects and caused an increase, higher than in TOL subjects, in PVP, while rehydration has greatly attenuated the PVP response to the HUT and decreased the PRA response. It is concluded that dehydration, together with measurements of SP, PP and PRA, may serve as a means of predicting orthostatic intolerance and may provide a physiological model for studying the causes of intolerance.

  11. Molecular Dynamics and Physical Stability of Amorphous Nimesulide Drug and Its Binary Drug-Polymer Systems.

    PubMed

    Knapik, J; Wojnarowska, Z; Grzybowska, K; Tajber, L; Mesallati, H; Paluch, K J; Paluch, M

    2016-06-01

    In this article we study the effectiveness of three well-known polymers: inulin, Soluplus, and PVP in stabilizing the amorphous form of nimesulide (NMS) drug. The recrystallization tendency of pure drug as well as measured drug-polymer systems were examined at isothermal conditions by broadband dielectric spectroscopy (BDS) and at nonisothermal conditions by differential scanning calorimetry (DSC). Our investigation has shown that the crystallization half-life time of pure NMS at 328 K is equal to 33 min. We found that this time can be prolonged to 40 years after adding 20% w/w PVP to NMS. This polymer proved to be the best NMS stabilizer, while the worst stabilization effect was exhibited by inulin. Additionally, our DSC, BDS, and FTIR studies indicate that for suppression of NMS recrystallization in the NMS-PVP system, the two mechanisms are responsible: the polymeric steric hindrances and the antiplastization effect exerted by the excipient. PMID:27149568

  12. Influence of surfactant on the preparation of silver nanoparticles by polyol method

    NASA Astrophysics Data System (ADS)

    Dung Dang, Thi My; Thu Tuyet Le, Thi; Fribourg-Blanc, Eric; Chien Dang, Mau

    2012-09-01

    In this study, silver nanoparticles were synthesized from silver nitrate via a polyol method in ambient atmosphere. In our synthesis route, polyvinylpyrrolidone (PVP) is used as both size controller and capping agent, ethylene glycol acts both as solvent and reducing agent. The obtained silver nanoparticles were characterized by ultraviolet-visible spectrophotometry which indicated the formation of nanoparticles. Investigation of Fourier transform infrared spectroscopy clearly demonstrated the coordination between silver nanoparticles and PVP. Transmission electron microscopy (TEM) contributed to the particle size analysis. The surface plasmon resonance peak in absorption spectra of silver colloidal solution showed absorption from 406 to 409 nm. The average size of the resulting silver nanoparticles was below 10 nm with a dependency on the PVP concentration.

  13. Solvothermal synthesis of uniform bismuth nanospheres using poly(N-vinyl-2-pyrrolidone) as a reducing agent

    PubMed Central

    2011-01-01

    Uniform bismuth nanospheres were successfully prepared from bismuth nitrate in the presence of poly(N-vinyl-2-pyrrolidone) (PVP) by solvothermal process. The product was characterized by powder X-ray diffraction, scanning electron microscopy, transmission electron microscopy, selected area electron diffraction, and energy-dispersive X-ray. PVP plays a critical role both as a reducing agent and a capping agent in the formation of bismuth nanospheres. Shape and size of bismuth nanospheres could be tuned by changing the employed PVP/bismuth salt ratio. It was also found the solvent had an effect on the morphologies of bismuth nanomaterials. The possible formation and growth mechanism of bismuth nanospheres were also discussed and proposed to explain the reduction step. PMID:21711606

  14. Formation and properties of porous films of lead zirconate titanate

    NASA Astrophysics Data System (ADS)

    Seregin, D. S.; Vorotilov, K. A.; Sigov, A. S.; Zubkova, E. N.; Abdullaev, D. A.; Kotova, N. M.; Vishnevskiy, A. S.

    2015-03-01

    The processes of formation and the properties of porous ceramic lead zirconate titanate films have been considered. The porous structure formed by thermal destruction of polyvinylpyrrolidone (PVP) with the molecular weight 29000 makes it possible to increase the cracking-free film thickness (by a factor of approximately two for one deposition at 20 wt % PVP; in this case, the volume porosity is 33%). An increase in the porosity decreases the permittivity ɛ; at 20 wt % PVP, ɛ = 432-456 depending on the film thickness. These values are less than those in nonporous films by a factor of more than two. An increase in the porosity is accompanied by an increase in the remanent polarization in the films. However, the hysteresis loop shape changes in the region of saturation polarization.

  15. Effects of intrauterine infusion of povidone-iodine on endometrial cytology and bacteriology in dairy cows with clinical endometritis.

    PubMed

    Mido, Shogo; Murata, Nozomu; Rawy, Mohamed Sadawy; Kitahara, Go; Osawa, Takeshi

    2016-05-01

    Endometritis is one of the major diseases causing infertility in the cow. Intrauterine infusion of povidone-iodine (PVP-I) is a common treatment. However, the optimal concentration of PVP-I for treating endometritis effectively remains unknown. We tested concentrations of 2.0% or 0.5% PVP-I for treating clinical endometritis in dairy cattle. In Experiment 1, bacteria isolated from the uterus were incubated with either 2.0% or 0.5% PVP-I, and the numbers of bacterial colonies were counted. In Experiment 2, 18 cows with clinical endometritis were treated with either 2.0% or 0.5% PVP-I (n=9 in each group). Cytology samples and bacteria were collected using a cytobrush on weeks 0 (W0), 1 (W1) and 2 (W2) after treatment. Subsequent reproductive performance was compared between the two groups. In Experiment 1, both concentrations had a similar antiseptic outcome. In Experiment 2, the percentage of polymorphonuclear neutrophils (PMN%) in the endometrial epithelium at W2 in the 2.0% group was significantly lower (P<0.05) than in the 0.5% group, although the PMN% decreased significantly from W0 to W2 (P<0.01) in both groups. Decreases in bacterial infection rates from W0 to W2 were similar in both groups. The first service conception rate was higher, numbers of services per conception were fewer, and time to conception was shorter in the 2.0% group than in the 0.5% group. Thus, an intrauterine infusion of 2.0% PVP-I was better than 0.5% in treating clinical endometritis in these dairy cattle. PMID:26655976

  16. Photoselective vaporization of the prostate in men taking clopidogrel

    PubMed Central

    Spernat, Daniel M. G.; Hossack, Tania A.; Woo, Henry H.

    2011-01-01

    Aim: To evaluate the peri-operative morbidity of men taking clopidogrel who underwent photoselective vaporisation of the prostate (PVP). Patients and Methods: A prospective database was collected. Between March 2005 and July 2010, 480 men underwent PVP. Of these, 18 men underwent PVP treatment while on clopidogrel. The surgery was carried out with either an 80W KTP laser or a 120W lithium triborate laser. Results: In the peri-operative period there were no complications related to PVP. There were no urinary tract infections, nor did any patient require bladder re-catheterisation. No cardiovascular events were reported within 3 months of the procedure. At 3 months post operatively, the International Prostate Symptom Score±standard deviation had improved from was 17.5±10.6 to 9.2±6.1 P<0.05. While the Quality of Life±standard deviation improved from 4.7±1.2 to 2.2±1.5 P<0.01. The maximum flow rate (Qmax), and post void residual volume (PVR) improved from 6.2±3.0 mL/s to 19.7±9.1 mL/s (P<0.01), and 140±102 mL to 59±77 mL (P<0.05), respectively. 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. PMID:21747600

  17. Physicochemical properties of tadalafil solid dispersions - Impact of polymer on the apparent solubility and dissolution rate of tadalafil.

    PubMed

    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. PMID:25998701

  18. Clinical Outcome and Safety of Multilevel Vertebroplasty: Clinical Experience and Results

    SciTech Connect

    Mailli, Leto Filippiadis, Dimitrios K.; Brountzos, Elias N.; Alexopoulou, Efthymia; Kelekis, Nikolaos; Kelekis, Alexios

    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. Effect of pH and biological media on polyvinylpyrrolidone-capped silver nanoparticles

    NASA Astrophysics Data System (ADS)

    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.

  20. Electrospun Polymer Blend Nanofibers for Tunable Drug Delivery: The Role of Transformative Phase Separation on Controlling the Release Rate.

    PubMed

    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. PMID:26655957

  1. AB070. Comparison of photoselective vaporization versus holmium laser enucleation for treatment of benign prostate hyperplasia in a small prostate volume

    PubMed Central

    Bae, Woong Jin; Bashraheel, Fahad; Choi, Sae Woong; Kim, Su Jin; Yoon, Byung Il; Kim, Sae Woong

    2016-01-01

    Objective Photoselective vaporization of the prostate (PVP) using GreenLight and Holmium laser enucleation of the prostate (HoLEP) is an important surgical technique for management of benign prostate hyperplasia (BPH). We aimed to compare the effectiveness and safety of PVP using a 120 W GreenLight laser with HoLEP in a small prostate volume. Methods Patients who underwent PVP or HoLEP surgery for BPH at our institutions were reviewed from May 2009 to December 2014 in this retrospective study. Among them, patients with prostate volumes <40 mL based on preoperative trans-rectal ultrasonography were included in this study. Peri-operative and post-operative parameters—such as International Prostate Symptom Score (IPSS), quality of life (QoL), maximum urinary flow rate (Qmax), post-void residual urine volume (PVR), and complications—were compared between the groups. Results PVP was performed in 176 patients and HoLEP in162 patients. Preoperative demographic data were similar in both groups, with the exception of PVR. Operative time and catheter duration did not show significant difference. Significant improvements compared to preoperative values were verified at the postoperative evaluation in both groups in terms of IPSS, QoL, Qmax, and PVR. Comparison of the postoperative parameters between the PVP and HoLEP groups demonstrated no significant difference, with the exception of IPSS voiding subscore at one month postoperatively (5.9 vs. 3.8, P<0.001). There was no significant difference in postoperative complications between the two groups. Conclusions Our data suggest that PVP and HoLEP are efficient and safe surgical treatment options for patients with small prostate volume.

  2. Role of Molecular Interactions for Synergistic Precipitation Inhibition of Poorly Soluble Drug in Supersaturated Drug-Polymer-Polymer Ternary Solution.

    PubMed

    Prasad, Dev; Chauhan, Harsh; Atef, Eman

    2016-03-01

    We are reporting a synergistic effect of combined Eudragit E100 and PVP K90 in precipitation inhibition of indomethacin (IND) in solutions at low polymer concentration, a phenomenon that has significant implications on the usefulness of developing novel ternary solid dispersion of poorly soluble drugs. The IND supersaturation was created by cosolvent technique, and the precipitation studies were performed in the absence and the presence of individual and combined PVP K90 and Eudragit E100. The studies were also done with PEG 8000 as a noninteracting control polymer. A continuous UV recording of the IND absorption was used to observe changes in the drug concentration over time. The polymorphic form and morphology of precipitated IND were characterized by Raman spectroscopy and scanning electron microscopy. The change in the chemical shift in solution (1)H NMR was used as novel approach to probe IND-polymer interactions. Molecular modeling was used for calculating binding energy between IND-polymer as another indication of IND-polymer interaction. Spontaneous IND precipitation was observed in the absence of polymers. Eudragit E100 showed significant inhibitory effect on nuclei formation due to stronger interaction as reflected in higher binding energy and greater change in chemical shift by NMR. PVP K90 led to significant crystal growth inhibition due to adsorption on growing IND crystals as confirmed by modified crystal habit of precipitate in the presence of PVP K90. Combination of polymers resulted in a synergistic precipitation inhibition and extended supersaturation. The NMR confirmed interaction between IND-Eudragit E100 and IND-PVP K90 in solution. The combination of polymers showed similar peak shift albeit using lower polymer concentration indicating stronger interactions. The results established the significant synergistic precipitation inhibition effect upon combining Eudragit E100 and PVP K90 due to drug-polymer interaction. PMID:26866895

  3. Surface capping and size-dependent toxicity of gold nanoparticles on different trophic levels.

    PubMed

    Iswarya, V; Manivannan, J; De, Arpita; Paul, Subhabrata; Roy, Rajdeep; Johnson, J B; Kundu, Rita; Chandrasekaran, N; Mukherjee, Anita; Mukherjee, Amitava

    2016-03-01

    In the present study, the toxicity of gold nanoparticles (Au NPs) was evaluated on various trophic organisms. Bacteria, algae, cell line, and mice were used as models representing different trophic levels. Two different sizes (CIT30 and CIT40) and surface-capped (CIT30-polyvinyl pyrrolidone (PVP)-capped) Au NPs were selected. CIT30 Au NP aggregated more rapidly than CIT40 Au NP, while an additional capping of PVP (CIT30-PVP capped Au NP) was found to enhance its stability in sterile lake water medium. Interestingly, all the forms of NPs evaluated were stable in the cell culture medium during the exposure period. Size- and dose-dependent cytotoxicities were observed in both bacteria and algae, with a strong dependence on reactive oxygen species (ROS) generation and lactate dehydrogenase (LDH) release. CIT30-PVP capped Au NP showed a significant decrease in toxicity compared to CIT30 Au NP in bacteria and algae. In the SiHa cell line, dose- and exposure-dependent decline in cell viability were noted for all three types of Au NPs. In mice, the induction of DNA damage was size and dose dependent, and surface functionalization with PVP reduced the toxic effects of CIT30 Au NP. The exposure to CIT30, CIT40, and CIT30-PVP capped Au NPs caused an alteration of the oxidative stress-related endpoints in mice hepatocytes. The toxic effects of the gold nanoparticles were found to vary in diverse test systems, accentuating the importance of size and surface functionalization at different trophic levels. PMID:26545887

  4. Field comparison of the point velocity probe with other groundwater velocity measurement methods

    NASA Astrophysics Data System (ADS)

    Labaky, W.; Devlin, J. F.; Gillham, R. W.

    2009-04-01

    Field testing of a new tool for measuring groundwater velocities at the centimeter scale, the point velocity probe (PVP), was undertaken at Canadian Forces Base, Borden, Ontario, Canada. The measurements were performed in a sheet pile-bounded alleyway in which bulk flow rate and direction could be controlled. PVP velocities were compared with those estimated from bulk flow, a Geoflo® instrument, borehole dilution, colloidal borescope measurements, and a forced gradient tracer test. In addition, the velocity profiles were compared with vertical variations in hydraulic conductivity (K) measured by permeameter testing of core samples and in situ high-resolution slug tests. There was qualitative agreement between the trends in velocity and K among all the various methods. The PVP and Geoflo® meter tests returned average velocity magnitudes of 30.2 ± 7.7 to 34.7 ± 13.1 cm/d (depending on prior knowledge of flow direction in PVP tests) and 36.5 ± 10.6, respectively, which were near the estimated bulk velocity (20 cm/d). The other direct velocity measurement techniques yielded velocity estimates 5 to 12 times the bulk velocity. Best results with the PVP instrument were obtained by jetting the instrument into place, though this method may have introduced a slight positive bias to the measured velocities. The individual estimates of point velocity direction varied, but the average of the point velocity directions agreed quite well with the expected bulk flow direction. It was concluded that the PVP method is a viable technique for use in the field, where high-resolution velocity data are required.

  5. Hepatic arterial phase and portal venous phase computed tomography for dose calculation of stereotactic body radiation therapy plans in liver cancer: a dosimetric comparison study

    PubMed Central

    2013-01-01

    Purpose To investigate the effect of computed tomography (CT) using hepatic arterial phase (HAP) and portal venous phase (PVP) contrast on dose calculation of stereotactic body radiation therapy (SBRT) for liver cancer. Methods Twenty-one patients with liver cancer were studied. HAP, PVP and non-enhanced CTs were performed on subjects scanned in identical positions under active breathing control (ABC). SBRT plans were generated using seven-field three-dimensional conformal radiotherapy (7 F-3D-CRT), seven-field intensity-modulated radiotherapy (7 F-IMRT) and single-arc volumetric modulated arc therapy (VMAT) based on the PVP CT. Plans were copied to the HAP and non-enhanced CTs. Radiation doses calculated from the three phases of CTs were compared with respect to the planning target volume (PTV) and the organs at risk (OAR) using the Friedman test and the Wilcoxon signed ranks test. Results SBRT plans calculated from either PVP or HAP CT, including 3D-CRT, IMRT and VMAT plans, demonstrated significantly lower (p <0.05) minimum absorbed doses covering 98%, 95%, 50% and 2% of PTV (D98%, D95%, D50% and D2%) than those calculated from non-enhanced CT. The mean differences between PVP or HAP CT and non-enhanced CT were less than 2% and 1% respectively. All mean dose differences between the three phases of CTs for OARs were less than 2%. Conclusions Our data indicate that though the differences in dose calculation between contrast phases are not clinically relevant, dose underestimation (IE, delivery of higher-than-intended doses) resulting from CT using PVP contrast is larger than that resulting from CT using HAP contrast when compared against doses based upon non-contrast CT in SBRT treatment of liver cancer using VMAT, IMRT or 3D-CRT. PMID:24209300

  6. A prospective, randomized comparative study of monopolar transurethral resection of the prostate versus photoselective vaporization of the prostate with GreenLight 120-W laser, in prostates less than 80 cc

    PubMed Central

    Okutucu, Tolga Muharrem; Suer, Evren; Burgu, Berk; Gulpinar, Omer; Yaman, Onder; Bozkurt, Selen

    2015-01-01

    Objective: In this study we aimed to compare photoselective vaporization (PVP) with the GreenLight 120-W Laser and monopolar transurethral resection as surgical treatments of prostates less than 80 cc in men with obstructive benign prostatic hyperplasia. Methods: From February 2009 to March 2012 we allocated 101 patients with a prostate glands of less than 80 cc; patients were randomly assigned for surgical treatment with monopolar transurethral resection of the prostate (TURP) (n = 62) or PVP (n = 39). Serum prostate specific antigen (PSA), International Prostate Symptom Score (IPSS), Sexual Health Inventory for Men (SHIM), maximum flow rate (Qmax) postmicturition residual (PMR), transrectal ultrasound volumes (TRUS), postvoid urine residual (PVR), complications, re-operations and hospitalization time were collected. The patients were seen in the follow up at 6, 12 and 24 months. Results: Median age was 69 (56–87) years old in the TURP group and 67 (51–87) years old in the PVP group. Mean preoperative prostate volume was 55 cc (40–72) and 60 cc (41–75) cc in the TURP group versus the PVP group. There was no statistically difference in subjectively (IPSS, SHIM) and objectively (Qmax-PMR) parameters and postoperatively complication rates between the two groups (p > 0.05). A significant difference was observed in the PVP group with a 2 (1–4) days hospital stay compared with 5 (3–9) days for the TURP group (p < 0.001). Conclusion: Prostate PVP and TURP are effective surgical treatments for benign prostatic hyperplasia. Postoperative functional improvements were durable and equivalent in the two groups. The two techniques have a similar complication rate. PMID:25642290

  7. Investigation and Evaluation of an in Situ Interpolymer Complex of Carbopol with Polyvinylpyrrolidone as a Matrix for Gastroretentive Tablets of Ranitidine Hydrochloride.

    PubMed

    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. PMID:26726743

  8. Oral subchronic exposure to silver nanoparticles in rats.

    PubMed

    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. PMID:27090107

  9. Chlorin e6 – polyvinylpyrrolidone mediated photosensitization is effective against human non-small cell lung carcinoma compared to small cell lung carcinoma xenografts

    PubMed Central

    Chin, William WL; Heng, Paul WS; Olivo, Malini

    2007-01-01

    Background Photodynamic therapy (PDT) is an effective local cancer treatment that involves light activation of a photosensitizer, resulting in oxygen-dependent, free radical-mediated cell death. Little is known about the comparative efficacy of PDT in treating non-small cell lung carcinoma (NSCLC) and small cell lung carcinoma (SCLC), despite ongoing clinical trials treating lung cancers. The present study evaluated the potential use of chlorin e6 – polyvinylpyrrolidone (Ce6-PVP) as a multimodality photosensitizer for fluorescence detection and photodynamic therapy (PDT) on NSCLC and SCLC xenografts. Results Human NSCLC (NCI-H460) and SCLC (NCI-H526) tumor cell lines were used to establish tumor xenografts in the chick chorioallantoic membrane (CAM) model as well as in the Balb/c nude mice. In the CAM model, Ce6-PVP was applied topically (1.0 mg/kg) and fluorescence intensity was charted at various time points. Tumor-bearing mice were given intravenous administration of Ce6-PVP (2.0 mg/kg) and laser irradiation at 665 nm (fluence of 150 J/cm2 and fluence rate of 125 mW/cm2). Tumor response was evaluated at 48 h post PDT. Studies of temporal fluorescence pharmacokinetics in CAM tumor xenografts showed that Ce6-PVP has a selective localization and a good accuracy in demarcating NSCLC compared to SCLC from normal surrounding CAM after 3 h post drug administration. Irradiation at 3 h drug-light interval showed greater tumor necrosis against human NSCLC xenografts in nude mice. SCLC xenografts were observed to express resistance to photosensitization with Ce6-PVP. Conclusion The formulation of Ce6-PVP is distinctly advantageous as a diagnostic and therapeutic agent for fluorescence diagnosis and PDT of NSCLC. PMID:18053148

  10. Effects of intrauterine infusion of povidone-iodine on endometrial cytology and bacteriology in dairy cows with clinical endometritis

    PubMed Central

    MIDO, Shogo; MURATA, Nozomu; RAWY, Mohamed Sadawy; KITAHARA, Go; OSAWA, Takeshi

    2015-01-01

    Endometritis is one of the major diseases causing infertility in the cow. Intrauterine infusion of povidone-iodine (PVP-I) is a common treatment. However, the optimal concentration of PVP-I for treating endometritis effectively remains unknown. We tested concentrations of 2.0% or 0.5% PVP-I for treating clinical endometritis in dairy cattle. In Experiment 1, bacteria isolated from the uterus were incubated with either 2.0% or 0.5% PVP-I, and the numbers of bacterial colonies were counted. In Experiment 2, 18 cows with clinical endometritis were treated with either 2.0% or 0.5% PVP-I (n=9 in each group). Cytology samples and bacteria were collected using a cytobrush on weeks 0 (W0), 1 (W1) and 2 (W2) after treatment. Subsequent reproductive performance was compared between the two groups. In Experiment 1, both concentrations had a similar antiseptic outcome. In Experiment 2, the percentage of polymorphonuclear neutrophils (PMN%) in the endometrial epithelium at W2 in the 2.0% group was significantly lower (P<0.05) than in the 0.5% group, although the PMN% decreased significantly from W0 to W2 (P<0.01) in both groups. Decreases in bacterial infection rates from W0 to W2 were similar in both groups. The first service conception rate was higher, numbers of services per conception were fewer, and time to conception was shorter in the 2.0% group than in the 0.5% group. Thus, an intrauterine infusion of 2.0% PVP-I was better than 0.5% in treating clinical endometritis in these dairy cattle. PMID:26655976

  11. [Role of mexidol (2-ethyl-6-methyl-3-hydroxypyridine succinate) in the obtaining of stabilized magnetite nanoparticles for biomedical application].

    PubMed

    Vazhnichaya, Ye M; Mokliak, Ye V; Kurapov, Yu A; Zabozlaev, A A

    2015-01-01

    Magnetite nanoparticles (NPs) are studied as agents for magnetic resonance imaging, hyperthermia of malignant tumors, targeted drug delivery as well as anti-anemic action. One of the main problems of such NPs is their aggregation that requires creation of methods for magnetite NPs stabilization during preparation of liquid medicinal forms on their basis. The present work is devoted to the possibility of mexidol (2-ethyl-6-methyl-3-hydroxypyridine succinate) use for solubilization of magnetite NPs in hydrophilic medium. For this purpose, the condensate produced by electron-beam evaporation and condensation, with magnetite particles of size 5-8 nm deposited into the crystals of sodium chloride were used in conjunction with substance of mexidol (2-ethyl-6-methyl-3-hydroxypyridine succinate), and low molecular weight polyvinylpyrrolidone (PVP). The NP condensate was dispersed in distilled water or PVP or mexidol solutions. NPs size distribution in the liquid phase of the systems was determined by photon correlation spectroscopy, iron (Fe) concentration was evaluated by atomic emission spectrometry. It is shown that in the dispersion prepared in distilled water, the major amount of NPs was of 13-120 nm in size, in mexidol solution - 270-1700 nm, in PVP solution - 30-900 nm. In the fluid containing magnetite NPs together with mexidol and PVP, the main fraction (99.9%) was characterized by the NPs size of 14-75 nm with maximum of 25 nm. This system had the highest iron concentration: it was similar to that in the sample with mexidol solution and 6.6-7.3 times higher than the concentration in the samples with distilled water or PVP. Thus, in the preparation of aqueous dispersions based on magnetite NPs condensate, mexidol provides a transition of Fe to the liquid phase in amount necessary to achieve its biological activity, and PVP stabilizes such modified NPs. PMID:26215417

  12. Poly(N-vinyl-2-pyrrolidone) elution from polysulfone dialysis membranes by varying solvent and wall shear stress.

    PubMed

    Namekawa, Koki; Matsuda, Masato; Fukuda, Makoto; Kaneko, Ami; Sakai, Kiyotaka

    2012-06-01

    Some dialysis patients are treated with post-hemodiafiltration (HDF); the blood viscosity of the patients who undergo post-HDF is higher than that of the patients who undergo conventional hemodialysis. This study aims to evaluate poly(N-vinyl-2-pyrrolidone) (PVP) elution from PSf dialysis membranes by varying solvents and high wall shear stress caused by blood viscosity. We tested three commercial membranes: APS-15SA (Asahi Kasei Kuraray), CX-1.6U (Toray) and FX140 (Fresenius). Dialysate and blood sides of the dialyzers were primed with reverse osmosis (RO) water and saline. RO water, saline and dextran solution (2.9 and 5.8 mPa s) were circulated in the blood side. The amount of eluted PVP was determined by 0.02 N iodometry. The hardness and adsorption force of human serum albumin (HSA) on the membrane surfaces were measured by the atomic force microscope. When wall shear stress was increased using dextran, the amount of PVP eluted by the 2.9 mPa s solution equaled that eluted by the 5.8 mPa s solution with APS-15SA and CX-1.6U sterilized by gamma rays. The amount of PVP eluted by the 5.8 mPa s solution was higher than that eluted by the 2.9 mPa s solution with FX140 sterilized by autoclaving. The wall shear stress increased the PVP elution from the surface, hardness and adsorption force of HSA. Sufficient gamma-ray irradiation is effective in decreasing PVP elution. PMID:22311608

  13. Comparison of Photoselective Vaporization versus Holmium Laser Enucleation for Treatment of Benign Prostate Hyperplasia in a Small Prostate Volume

    PubMed Central

    Kim, Kang Sup; Choi, Jin Bong; Bae, Woong Jin; Kim, Su Jin; Cho, Hyuk Jin; Hong, Sung-Hoo; Lee, Ji Youl; Kim, Sang Hoon; Kim, Hyun Woo; Cho, Su Yeon; Kim, Sae Woong

    2016-01-01

    Objective Photoselective vaporization of the prostate (PVP) using GreenLight and Holmium laser enucleation of the prostate (HoLEP) is an important surgical technique for management of benign prostate hyperplasia (BPH). We aimed to compare the effectiveness and safety of PVP using a 120 W GreenLight laser with HoLEP in a small prostate volume. Methods Patients who underwent PVP or HoLEP surgery for BPH at our institutions were reviewed from May 2009 to December 2014 in this retrospective study. Among them, patients with prostate volumes < 40 mL based on preoperative trans-rectal ultrasonography were included in this study. Peri-operative and post-operative parameters—such as International Prostate Symptom Score (IPSS), quality of life (QoL), maximum urinary flow rate (Qmax), post-void residual urine volume (PVR), and complications—were compared between the groups. Results PVP was performed in 176 patients and HoLEP in162 patients. Preoperative demographic data were similar in both groups, with the exception of PVR. Operative time and catheter duration did not show significant difference. Significant improvements compared to preoperative values were verified at the postoperative evaluation in both groups in terms of IPSS, QoL, Qmax, and PVR. Comparison of the postoperative parameters between the PVP and HoLEP groups demonstrated no significant difference, with the exception of IPSS voiding subscore at 1 month postoperatively (5.9 vs. 3.8, P< 0.001). There was no significant difference in postoperative complications between the two groups. Conclusion Our data suggest that PVP and HoLEP are efficient and safe surgical treatment options for patients with small prostate volume. PMID:27227564

  14. Effect of hydration on plasma volume and endocrine responses to water immersion

    NASA Technical Reports Server (NTRS)

    Harrison, M. H.; Keil, L. C.; Wade, C. A.; Silver, J. E.; Geelen, G.

    1986-01-01

    The effect of hydration status on early endocrine responses and on osmotic and intravascular volume changes during immersion was determined in humans undergoing successive periods of dehydration, immersion, rehydration, and immersion. Immersion caused an isotonic expansion of plasma volume, as well as suppression of plasma renin activity and aldosterone, which all occurred independently of hydration status. On the other hand, the concentration of plasma vasopressin (PVP) was found to decrease during dehydrated immersion, but not during rehydrated immersion. It is concluded that plasma tonicity is not a factor influencing PVP suppression during water immersion.

  15. Acetylene-derived polymers and their applications in hair and skin care.

    PubMed

    Petter, P J

    1989-02-01

    Synopsis Since the introduction over 30 years ago of polyvinylpyrrolidone (PVP) as the first synthetic hairspray resin, acetylene-derived polymers have found wide and increasing applications in the cosmetics and toiletries industry. This review covers the two main classes of acetylenic polymers. In the first class, in which the chemistry may be traced back to reaction of acetylene with formaldehyde, are included PVP homopolymers and copolymers of VP with vinyl acetate, dimethylaminoethyl methacrylate, vinylcaprolactam and styrene. In the second class, stemming from reaction of acetylene with methanol, are the poly (vinyl methyl ether/maleic acid) monoester resins. PMID:19456933

  16. Identifying inhibitors of hydrate formation rate with viscometric experiments

    SciTech Connect

    Kalbus, J.S.; Christiansen, R.L.; Sloan, D. Jr.

    1995-12-31

    Inhibiting the rate of hydrate formation with low concentration additives is an economically and environmentally attractive alternative to prevention of hydrates with large doses of methanol. Here, a method for screening possible rate inhibitors is described. In the method, a viscometer is used to follow the development of hydrate formation for water-THF solutions and for water-gas solutions at conditions favoring hydrate formation. The method was applied to about 30 different chemicals, plus binary combinations of many of these chemicals. The best chemical additives included BASF F-127, Mirawet ASC, Surfynol-465, sodium dodecyl sulfate(SDS), Mirataine CBS with polyvinylpyrrolidone(PVP), and SDS with PVP.

  17. Vortex fluidic entrapment of functional microalgal cells in a magnetic polymer matrix

    NASA Astrophysics Data System (ADS)

    Eroglu, Ela; D'Alonzo, Nicholas J.; Smith, Steven M.; Raston, Colin L.

    2013-03-01

    Composite materials based on superparamagnetic magnetite nanoparticles embedded in polyvinylpyrrolidone (PVP) are generated in a continuous flow vortex fluidic device (VFD). The same device is effective in entrapping microalgal cells within this material, such that the functional cells can be retrieved from aqueous dispersions using an external magnet.Composite materials based on superparamagnetic magnetite nanoparticles embedded in polyvinylpyrrolidone (PVP) are generated in a continuous flow vortex fluidic device (VFD). The same device is effective in entrapping microalgal cells within this material, such that the functional cells can be retrieved from aqueous dispersions using an external magnet. Electronic supplementary information (ESI) available. See DOI: 10.1039/c3nr33813d

  18. One-pot synthesis of single-crystal Pt nanoplates uniformly deposited on reduced graphene oxide, and their high activity and stability on the electrocalalytic oxidation of methanol.

    PubMed

    Hao, Yanfei; Wang, Xudan; Shen, Jianfeng; Yuan, Junhua; Wang, Ai-Jun; Niu, Li; Huang, Shengtang

    2016-04-01

    We demonstrate a one-pot thermoreduction approach towards the preparation of single-crystal Pt nanoplates, which were uniformly deposited on the reduced graphene oxide (RGO) using polyvinylpyrrolidone (PVP) as a stabilizer. The size of Pt nanoplates can be tuned from 6.8 to 10.1 nm by controlling Pt loading. The as-prepared Pt/PVP/RGO catalysts show high stability and activity towards the methanol oxidation reaction (MOR). Their MOR current can reach up to 401 mA mg(-1) Pt and MOR current can maintain 89.4% of its initial value after 10 000 potential cycles. PMID:26906081

  19. Nonlinear optical properties of new organotellurium compounds containing azomethine and azo groups under CW laser illumination

    NASA Astrophysics Data System (ADS)

    Saadon, H. L.; Ali, Basil; Al-Fregi, Adil A.

    2014-06-01

    Two new organotellurium compounds containing azomethine and azo groups, [2-(2-hydroxynaphthylazo)phenyl][2-(2-methoxybenzylideneamino)-5-methylphenyl]tellurium dibromide (P1) and [2-(2-hydroxynaphthylazo)-5-nitrophenyl][2-(2-methoxy benzylideneamino)-5-methyl phenyl]tellurium dibromide (P2) were synthesized and doped in polyvinylprodidone (PVP) matrix. The nonlinear optical (NLO) properties of these compounds and doped polymer were studied using Z-scan technique at 532 nm. The Z-scan results reveal that the sample solutions and films exhibit self-defocusing nonlinearity. The P2/PVP solutions investigated here exhibit good optical power limiting.

  20. Anomalous diffusion of erythrocytes in the presence of polyvinylpyrrolidone.

    PubMed Central

    Fritz, O G

    1984-01-01

    The diffusion coefficient of erythrocytes was measured using quasi-elastic light-scattering (QELS) techniques. The cells were suspended in phosphate-buffered saline solutions with and without a macromolecule, polyvinylpyrrolidone (PVP[360]). In the presence of the PVP(360) an anomalously high diffusion coefficient was measured for metabolizing cells with a normal transmembrane potential. The results are in agreement with experiments on rouleau formation by red blood cells and are supportive of the hypothesis of a long-range coherent interaction between metabolically active biological cells. Images FIGURE 8 FIGURE 9 FIGURE 10 PMID:6478035

  1. Surface-enhanced raman spectroscopy substrate for arsenic sensing in groundwater

    DOEpatents

    Yang, Peidong; Mulvihill, Martin; Tao, Andrea R.; Sinsermsuksakul, Prasert; Arnold, John

    2015-06-16

    A surface-enhanced Raman spectroscopy (SERS) substrate formed from a plurality of monolayers of polyhedral silver nanocrystals, wherein at least one of the monolayers has polyvinypyrrolidone (PVP) on its surface, and thereby configured for sensing arsenic is described. Highly active SERS substrates are formed by assembling high density monolayers of differently shaped silver nanocrystals onto a solid support. SERS detection is performed directly on this substrate by placing a droplet of the analyte solution onto the nanocrystal monolayer. Adsorbed polymer, polyvinypyrrolidone (PVP), on the surface of the nanoparticles facilitates the binding of both arsenate and arsenite near the silver surface, allowing for highly accurate and sensitive detection capabilities.

  2. Photoinduced electron transfer reaction in polymer-surfactant aggregates: Photoinduced electron transfer between N,N-dimethylaniline and 7-amino coumarin dyes

    SciTech Connect

    Chakraborty, Anjan; Seth, Debabrata; Setua, Palash; Sarkar, Nilmoni

    2008-05-28

    Photoinduced electron transfer between coumarin dyes and N,N-dimethylaniline has been investigated by using steady state and picosecond time resolved fluorescence spectroscopy in sodium dodecyl sulphate (SDS) micelles and PVP-polyvinyl pyrrolidone (SDS) polymer-surfactant aggregates. A slower rate of electron transfer is observed in PVP-SDS aggregates than in polymer-free SDS micelles. A Marcus type inversion is observed in the correlation of free energy change in comparison with the electron transfer rate. The careful investigation reveals that C-151 deviates from the normal Marcus inverted region compared to its analogs C-152 and C-481 due to slower rotational relaxation and smaller translational diffusion coefficient.

  3. The polyvinylpyrrolidone functionalized rGO/Bi2S3 nanocomposite as a near-infrared light-responsive nanovehicle for chemo-photothermal therapy of cancer

    NASA Astrophysics Data System (ADS)

    Dou, Ruixia; Du, Zhen; Bao, Tao; Dong, Xinghua; Zheng, Xiaopeng; Yu, Miao; Yin, Wenyan; Dong, Binbin; Yan, Liang; Gu, Zhanjun

    2016-06-01

    Recently, a combination of chemotherapy with photothermal therapy (PTT) has received great attention for the construction of a near infrared (NIR)-controlled drug-delivery system for synergistic treatment of cancer, ultimately resulting in the enhancement of the therapeutic efficacy of anticancer drugs. Here, we developed a novel system for synergistic cancer therapy based on bismuth sulfide (Bi2S3) nanoparticle-decorated graphene functionalized with polyvinylpyrrolidone (PVP) (named PVP-rGO/Bi2S3). The as-prepared PVP-rGO/Bi2S3 nanocomposite has a high storage capacity for anticancer drugs (~500% for doxorubicin (DOX)) and simultaneously has perfect photothermal conversion efficiency in the NIR region. The results of the in vitro accumulative drug release test manifests that the PVP-rGO/Bi2S3 nanocomposite could be applied as a dual pH- and NIR-responsive nanotherapeutic carrier for the controlled release of DOX from DOX-loaded PVP-rGO/Bi2S3 (PVP-rGO/Bi2S3@DOX). Moreover, the treatment of both cancer cells (including Hela, MCF-7, HepG2 and BEL-7402 cells) and BEL-7402 tumor-bearing mice with the PVP-rGO/Bi2S3@DOX complex followed by NIR laser irradiation produces significantly greater inhibition of cancer cell growth than the treatment with NIR irradiation alone or DOX alone, exhibiting a synergistic antitumor effect. Furthermore, due to the obvious NIR and X-ray absorption ability, the PVP-rGO/Bi2S3 nanocomposite could be employed as a dual-modal contrast agent for both photoacoustic tomography and X-ray computed tomography imaging. In addition to the good biocompatibility, the PVP-rGO/Bi2S3 nanocomposite paves a potential way for the fabrication of theranostic agents for dual-modal imaging-guided chemo-photothermal combined cancer therapy.Recently, a combination of chemotherapy with photothermal therapy (PTT) has received great attention for the construction of a near infrared (NIR)-controlled drug-delivery system for synergistic treatment of cancer, ultimately

  4. Novel solid-state route to nanostructured tin, zinc and cerium oxides as potential materials for sensors.

    PubMed

    Diaz, C; Platoni, S; Molina, A; Valenzuela, M L; Geaney, H; O'Dwyer, C

    2014-09-01

    Solid-state sensor nanostructured materials (SnO2, ZnO and CeO2) have been prepared by pyrolysis of macromolecular complexes: PSP-co-4-PVP x (SnCl2)n, PSP-co-4-PVP x (ZnCl2)n and PSP-co-4-PVP x (Ce(NO3)3)n in several molar ratios under air at 800 degrees C. The as-prepared nanostructured SnO2 exhibits morphologies and particle sizes which are dependent upon the molar ratio of the SnCl2:PSP-co-4-PVP. When a larger weight fraction of the inorganic salt in the precursor mixture is used (1:10 > 1:5 > 1.1) larger crystalline crystals are found for each oxide. For ZnO and CeO2 agglomerates of morphologies from the respective hexagonal and cubic structures were observed with typical sizes of 30-50 nm in both cases for a precursor mixture ratio of 1:1. PMID:25924326

  5. Peak-valley-peak pattern of histone modifications delineates active regulatory elements and their directionality.

    PubMed

    Pundhir, Sachin; Bagger, Frederik O; Lauridsen, Felicia B; Rapin, Nicolas; Porse, Bo T

    2016-05-19

    Formation of nucleosome free region (NFR) accompanied by specific histone modifications at flanking nucleosomes is an important prerequisite for enhancer and promoter activity. Due to this process, active regulatory elements often exhibit a distinct shape of histone signal in the form of a peak-valley-peak (PVP) pattern. However, different features of PVP patterns and their robustness in predicting active regulatory elements have never been systematically analyzed. Here, we present PARE, a novel computational method that systematically analyzes the H3K4me1 or H3K4me3 PVP patterns to predict NFRs. We show that NFRs predicted by H3K4me1 and me3 patterns are associated with active enhancers and promoters, respectively. Furthermore, asymmetry in the height of peaks flanking the central valley can predict the directionality of stable transcription at promoters. Using PARE on ChIP-seq histone modifications from four ENCODE cell lines and four hematopoietic differentiation stages, we identified several enhancers whose regulatory activity is stage specific and correlates positively with the expression of proximal genes in a particular stage. In conclusion, our results demonstrate that PVP patterns delineate both the histone modification landscape and the transcriptional activities governed by active enhancers and promoters, and therefore can be used for their prediction. PARE is freely available at http://servers.binf.ku.dk/pare. PMID:27095194

  6. Mechanistic insights into formation of SnO₂ nanotubes: asynchronous decomposition of poly(vinylpyrrolidone) in electrospun fibers during calcining process.

    PubMed

    Wu, Jinjin; Zeng, Dawen; Wang, Xiaoxia; Zeng, Lei; Huang, Qingwu; Tang, Gen; Xie, Changsheng

    2014-09-23

    The formation mechanism of SnO2 nanotubes (NTs) fabricated by generic electrospinning and calcining was revealed by systematically investigating the structural evolution of calcined fibers, product composition, and released volatile byproducts. The structural evolution of the fibers proceeded sequentially from dense fiber to wire-in-tube to nanotube. This remarkable structural evolution indicated a disparate thermal decomposition of poly(vinylpyrrolidone) (PVP) in the interior and the surface of the fibers. PVP on the surface of the outer fibers decomposed completely at a lower temperature (<340 °C), due to exposure to oxygen, and SnO2 crystallized and formed a shell on the fiber. Interior PVP of the fiber was prone to loss of side substituents due to the oxygen-deficient decomposition, leaving only the carbon main chain. The rest of the Sn crystallized when the pores formed resulting from the aggregation of SnO2 nanocrystals in the shell. The residual carbon chain did not decompose completely at temperatures less than 550 °C. We proposed a PVP-assisted Ostwald ripening mechanism for the formation of SnO2 NTs. This work directs the fabrication of diverse nanostructure metal oxide by generic electrospinning method. PMID:25162977

  7. Enhanced bioavailability of sirolimus via preparation of solid dispersion nanoparticles using a supercritical antisolvent process

    PubMed Central

    Kim, Min-Soo; Kim, Jeong-Soo; Park, Hee Jun; Cho, Won Kyung; Cha, Kwang-Ho; Hwang, Sung-Joo

    2011-01-01

    Background The aim of this study was to improve the physicochemical properties and bioavailability of poorly water-soluble sirolimus via preparation of a solid dispersion of nanoparticles using a supercritical antisolvent (SAS) process. Methods First, excipients for enhancing the stability and solubility of sirolimus were screened. Second, using the SAS process, solid dispersions of sirolimus-polyvinylpyrrolidone (PVP) K30 nanoparticles were prepared with or without surfactants such as sodium lauryl sulfate (SLS), tocopheryl propylene glycol succinate, Sucroester 15, Gelucire 50/13, and Myrj 52. A mean particle size of approximately 250 nm was obtained for PVP K30-sirolimus nanoparticles. Solid state characterization, kinetic solubility, powder dissolution, stability, and pharmacokinetics were analyzed in rats. Results X-ray diffraction, differential scanning calorimetry, and high-pressure liquid chromatography indicated that sirolimus existed in an anhydrous amorphous form within a solid dispersion of nanoparticles and that no degradation occurred after SAS processing. The improved supersaturation and dissolution of sirolimus as a solid dispersion of nanoparticles appeared to be well correlated with enhanced bioavailability of oral sirolimus in rats. With oral administration of a solid dispersion of PVP K30-SLS-sirolimus nanoparticles, the peak concentration and AUC0→12h of sirolimus were increased by approximately 18.3-fold and 15.2-fold, respectively. Conclusion The results of this study suggest that preparation of PVP K30-sirolimus-surfactant nanoparticles using the SAS process may be a promising approach for improving the bioavailability of sirolimus. PMID:22162657

  8. 7 CFR 91.5 - Where services are offered.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...) Office. The PVP office and plant examination facility of the Science and Technology programs issues... is located as follows: USDA, AMS, Science & Technology Programs, Plant Variety Protection Office... offered to applicants at the Science and Technology laboratories and facilities as listed below....

  9. Tuning the thermal diffusivity of silver based nanofluids by controlling nanoparticle aggregation.

    PubMed

    Agresti, Filippo; Barison, Simona; Battiston, Simone; Pagura, Cesare; Colla, Laura; Fedele, Laura; Fabrizio, Monica

    2013-09-13

    With the aim of preparing stable nanofluids for heat exchange applications and to study the effect of surfactant on the aggregation of nanoparticles and thermal diffusivity, stable silver colloids were synthesized in water by a green method, reducing AgNO₃ with fructose in the presence of poly-vinylpyrollidone (PVP) of various molecular weights. A silver nanopowder was precipitated from the colloids and re-dispersed at 4 vol% in deionized water. The Ag colloids were characterized by UV-visible spectroscopy, combined dynamic light scattering and ζ-potential measurements, and laser flash thermal diffusivity. The Ag nanopowders were characterized by scanning electron microscopy and thermal gravimetric analysis. It was found that the molecular weight of PVP strongly affects the ζ-potential and the aggregation of nanoparticles, thereby affecting the thermal diffusivity of the obtained colloids. In particular, it was observed that on increasing the molecular weight of PVP the absolute value of the ζ-potential is reduced, leading to increased aggregation of nanoparticles. A clear relation was identified between thermal diffusivity and aggregation, showing higher thermal diffusivity for nanofluids having higher aggregation. A maximum improvement of thermal diffusivity by about 12% was found for nanofluids prepared with PVP having higher molecular weight. PMID:23942258

  10. Tuning the thermal diffusivity of silver based nanofluids by controlling nanoparticle aggregation

    NASA Astrophysics Data System (ADS)

    Agresti, Filippo; Barison, Simona; Battiston, Simone; Pagura, Cesare; Colla, Laura; Fedele, Laura; Fabrizio, Monica

    2013-09-01

    With the aim of preparing stable nanofluids for heat exchange applications and to study the effect of surfactant on the aggregation of nanoparticles and thermal diffusivity, stable silver colloids were synthesized in water by a green method, reducing AgNO3 with fructose in the presence of poly-vinylpyrollidone (PVP) of various molecular weights. A silver nanopowder was precipitated from the colloids and re-dispersed at 4 vol% in deionized water. The Ag colloids were characterized by UV-visible spectroscopy, combined dynamic light scattering and ζ-potential measurements, and laser flash thermal diffusivity. The Ag nanopowders were characterized by scanning electron microscopy and thermal gravimetric analysis. It was found that the molecular weight of PVP strongly affects the ζ-potential and the aggregation of nanoparticles, thereby affecting the thermal diffusivity of the obtained colloids. In particular, it was observed that on increasing the molecular weight of PVP the absolute value of the ζ-potential is reduced, leading to increased aggregation of nanoparticles. A clear relation was identified between thermal diffusivity and aggregation, showing higher thermal diffusivity for nanofluids having higher aggregation. A maximum improvement of thermal diffusivity by about 12% was found for nanofluids prepared with PVP having higher molecular weight.

  11. Improvement of Physico-mechanical Properties of Partially Amorphous Acetaminophen Developed from Hydroalcoholic Solution Using Spray Drying Technique

    PubMed Central

    Sadeghi, Fatemeh; Torab, Mansour; Khattab, Mostafa; Homayouni, Alireza; Afrasiabi Garekani, Hadi

    2013-01-01

    Objective(s): This study was performed aiming to investigate the effect of particle engineering via spray drying of hydroalcoholic solution on solid states and physico-mechanical properties of acetaminophen. Materials and Methods: Spray drying of hydroalcoholic solution (25% v/v ethanol/water) of acetaminophen (5% w/v) in the presence of small amounts of polyninylpyrrolidone K30 (PVP) (0, 1.25, 2.5 and 5% w/w based on acetaminophen weight) was carried out. The properties of spray dried particles namely morphology, surface characteristics, particle size, crystallinity, dissolution rate and compactibility were evaluated. Results: Spray drying process significantly changed the morphology of acetaminophen crystals from acicular (rod shape) to spherical microparticle. Differential scanning calorimetery (DSC) and x-ray powder diffraction (XRPD) studies ruled out any polymorphism in spray dried samples, however, a major reduction in crystallinity up to 65%, especially for those containing 5% w/w PVP was observed. Spray dried acetaminophen particles especially those obtained in the presence of PVP exhibited an obvious improvement of the dissolution and compaction properties. Tablets produced from spray dried samples exhibited excellent crushing strengths and no tendency to cap. Conclusions: The findings of this study revealed that spray drying of acetaminophen from hydroalcoholic solution in the presence of small amount of PVP produced partially amorphous particles with improved dissolution and excellent compaction properties. PMID:24379968

  12. The Role of Polyvinylpyrrolidone in Hydrothermally Synthesized Ag/ZnO Nanocomposites and Their Photocatalytic Activities.

    PubMed

    Mavrič, Tina; Emin, Saim; Valant, Matjaž; Peng, Wenqin; Stangar, Urkaška Lavrenčič

    2015-09-01

    Here we present a simple hydrothermal route for the preparation of photoactive ZnO and Ag/ZnO nanoparticles (NPs) synthesized in the presence and absence of polyvinylpyrrolidone (PVP). The low temperature synthesis is carried out in ethylene glycol (EG) medium at 180 degrees C, where EG is used as a reducing agent for the Ag+ ions. PVP is exploited as a size confining matrix for the Ag NPs. The present synthetic protocol allows the preparation of ZnO nanorods (NRs) with typical lengths of -200 nm and Ag/ZnO NPs with typical sizes of -100 nm. The photocatalytic activity of the as-prepared nanomaterials was tested for degradation of model pollutant methyl orange (MO) dye and terephthalic acid (TPA). We found that the Ag/ZnO NPs synthesized in PVP showed higher photoactivity than the commercial TiO2 (P25) powder or ZnO and Ag/ZnO NPs synthesized without PVP. PMID:26716210

  13. Video Game Genre as a Predictor of Problem Use

    PubMed Central

    Golub, Andrew; Ream, Geoffrey; Dunlap, Eloise

    2012-01-01

    Abstract This study assessed how problem video game playing (PVP) varies with game type, or “genre,” among adult video gamers. Participants (n=3,380) were adults (18+) who reported playing video games for 1 hour or more during the past week and completed a nationally representative online survey. The survey asked about characteristics of video game use, including titles played in the past year and patterns of (problematic) use. Participants self-reported the extent to which characteristics of PVP (e.g., playing longer than intended) described their game play. Five percent of our sample reported moderate to extreme problems. PVP was concentrated among persons who reported playing first-person shooter, action adventure, role-playing, and gambling games most during the past year. The identification of a subset of game types most associated with problem use suggests new directions for research into the specific design elements and reward mechanics of “addictive” video games and those populations at greatest risk of PVP with the ultimate goal of better understanding, preventing, and treating this contemporary mental health problem. PMID:22242785

  14. Morphological transformations of silver nanoparticles in seedless photochemical synthesis

    NASA Astrophysics Data System (ADS)

    Lu, Ya; Zhang, Congyun; Hao, Rui; Zhang, Dongjie; Fu, Yizheng; Moeendarbari, Sina; Pickering, Christopher S.; Hao, Yaowu; Liu, Yaqing

    2016-05-01

    Photochemical synthesis is an easily controlled and reliable method for the fabrication of silver (Ag) nanoparticles with various morphologies. In this work, we have systematically investigated the seedless photochemical synthesis of anisotropic Ag nanoparticles with and without PVP as surface capping agent. The time evolution of anisotropic Ag nanoparticles during the synthesis process are studied using UV–visible spectra, optical images and transmission electron microscopy. The results show that the light irradiation precisely controls the start and termination of the reaction, and the presence or absence of PVP greatly affects the morphology evolution of anisotropic Ag nanoparticles. With PVP as the surface capping agent, Ag nanoparticles grow into decahedra or prism by the deposition of Ag atoms on {111} or {110} facets through epitaxial growth. However, a different morphology evolution could happen when Ag nanoparticle is synthesized without PVP as surface capping agent. In this case, Ag nanoparticles can fuse into the decahedrons through an edge-selective particle fusion mechanism, which involves attachment, rotation and realignment of Ag nanoparticles. This process was evidenced with HRTEM images at the different stages of the transformation from Ag colloid to decahedra nanoparticles. Oriented attachment and Ostwald ripening also play important role in the transformation process.

  15. Medicated Janus fibers fabricated using a Teflon-coated side-by-side spinneret.

    PubMed

    Yu, Deng-Guang; Yang, Chen; Jin, Miao; Williams, Gareth R; Zou, Hua; Wang, Xia; Bligh, S W Annie

    2016-02-01

    A family of medicated Janus fibers that provides highly tunable biphasic drug release was fabricated using a side-by-side electrospinning process employing a Teflon-coated parallel spinneret. The coated spinneret facilitated the formation of a Janus Taylor cone and in turn high quality integrated Janus structures, which could not be reliably obtained without the Teflon coating. The fibers prepared had one side consisting of polyvinylpyrrolidone (PVP) K60 and ketoprofen, and the other of ethyl cellulose (EC) and ketoprofen. To modulate and tune drug release, PVP K10 was doped into the EC side in some cases. The fibers were linear and had flat morphologies with an indent in the center. They provide biphasic drug release, with the PVP K60 side dissolving very rapidly to deliver a loading dose of the active ingredient, and the EC side resulting in sustained release of the remaining ketoprofen. The addition of PVP K10 to the EC side was able to accelerate the second stage of release; variation in the dopant amount permitted the release rate and extent this phase to be precisely tuned. These results offer the potential to rationally design systems with highly controllable drug release profiles, which can complement natural biological rhythms and deliver maximum therapeutic effects. PMID:26674839

  16. Core-Shell Silver/Polymeric Nanoparticles-Based Combinatorial Therapy against Breast Cancer In-vitro

    NASA Astrophysics Data System (ADS)

    Elbaz, Nancy M.; Ziko, Laila; Siam, Rania; Mamdouh, Wael

    2016-08-01

    The current study aimed at preparing AgNPs and three different core-shell silver/polymeric NPs composed of Ag core and three different polymeric shells: polyvinyl alcohol (PVA), polyethylene glycol (PEG) and polyvinylpyrrolidone (PVP). Thereafter, the core/shell NPs were loaded with a chemotherapeutic agent doxorubicin (DOX). Finally, the cytotoxic effects of the different core-shell Ag/polymeric NPs-based combinatorial therapeutics were tested in-vitro against breast cancer (MCF-7) and human fibroblast (1BR hTERT) cell lines. AgNPs, Ag/PVA and Ag/PVP NPs were more cytotoxic to MCF-7 cells than normal fibroblasts, as well as DOX-Ag, DOX-Ag/PVA, DOX-Ag/PEG and DOX-Ag/PVP nanocarriers (NCs). Notably, low dosage of core-shell DOX-loaded Ag/polymeric nanocarriers (NCs) exhibited a synergic anticancer activity, with DOX-Ag/PVP being the most cytotoxic. We believe that the prepared NPs-based combinatorial therapy showed a significant enhanced cytotoxic effect against breast cancer cells. Future studies on NPs-based combinatorial therapy may aid in formulating a novel and more effective cancer therapeutics.

  17. Detection of Silver Nanoparticles in Cells by Flow Cytometry Using Light Scattering and Far-red Fluorescence

    EPA Science Inventory

    The cellular uptake of different sized silver nanoparticles (l0 nm, 50 nm, and 75nm) coated with polyvinylpyrrolidone (PVP) or citrate in ARPE-19 cells following 24 hour incubation was detected by side scatter through the use of a flow cytometer. A large far red fluorescence sign...

  18. A monomeric photosensitizer for targeted cancer therapy.

    PubMed

    Liang, Ruizheng; Ma, Lina; Zhang, Lele; Li, Chunyang; Liu, Wendi; Wei, Min; Yan, Dan; Evans, David G; Duan, Xue

    2014-12-11

    A targeted photosensitizer used in photodynamic therapy (PDT) was fabricated by incorporation of zinc phthalocyanine (ZnPc) and folic acid (FA) into polyvinylpyrrolidone (PVP) micelles, which exhibits excellent anticancer performance revealed by both in vitro studies and in vivo tests. PMID:25327438

  19. Formation of organic nanoparticles from volatile microemulsions.

    PubMed

    Margulis-Goshen, Katrin; Netivi, Hadas Donio; Major, Dan T; Gradzielski, Michael; Raviv, Uri; Magdassi, Shlomo

    2010-02-15

    A method for preparation of nanoparticles of poorly water-soluble organic materials is presented. By this method, an oil-in-water microemulsion containing a volatile solvent with dissolved model material, propylparaben, undergoes solvent evaporation and conversion into nanoparticles by spray drying. The resulting powder can be easily dispersed in water to give a clear, stable dispersion of nanoparticles with a high loading of propylparaben. By filtration of this dispersion it was found that more than 95wt.% of the dispersed propylparaben is in particles of less than 450nm. X-ray diffraction revealed that propylparaben is present as nanocrystals of 40-70nm. After dispersion of the powder in water, formation of large crystals rapidly occurs. Addition of polyvinylpyrrolidone (PVP) prevented crystal growth during dispersion of the powder in water. The inhibition of propylparaben crystal growth by PVP was studied by molecular dynamic simulations that addressed the binding of PVP to the propylparaben crystal. A comparison was made between PVP and polyvinylalcohol, which did not display crystal inhibition properties. PMID:19919861

  20. Solution thermodynamics of poly(vinyl pyrrolidone) in ethanol/CCl{sub 4} mixtures

    SciTech Connect

    Schwager, F.; Marand, E.; Davis, R.M.

    1996-12-31

    The Gibbs free energy, the enthalpy, and the entropy of mixing of ethanol with the polymer polyvinylpyrrolidone, PVP, and with its low molecular weight analogue, N-ethylpyrrolidone, NEP were calculated. The calculation of the free energy of mixing was achieved with the thermodynamic model for hydrogen bonded polymer systems developed by Painter, Coleman, and Graf. This model, based on the use of an association model, gives the free energy of mixing as a function of the Flory-Huggins interaction parameter, the composition of the mixture, and the association equilibrium constants. The self-association of the ethanol molecules was described by two equilibrium constants, one for the formation of dimers and one for the formation of multimers. The equilibrium constants of inter-association of PVP or NEP with ethanol were determined from the quantitative analysis of NEP/ethanol and PVP/ethanol FTIR spectra at various temperatures and compositions. The values of the equilibrium constants were then used to calculate the theoretical Gibbs free energy of mixing as a function of the composition. The enthalpic and entropic contributions to mixing were compared for the NEP/ethanol and PVP/ethanol mixtures.

  1. Synthesis of spinel LiNi0.5Mn1.5O4 with secondary plate morphology as cathode material for lithium ion batteries

    NASA Astrophysics Data System (ADS)

    Risthaus, Tim; Wang, Jun; Friesen, Alex; Wilken, Andrea; Berghus, Debbie; Winter, Martin; Li, Jie

    2015-10-01

    Spinel LiNi0.5Mn1.5O4 material has been synthesized by a spray drying process and subsequent solid state reaction. Polyvinylpyrrolidone (PVP) is given as additive to the spray drying precursor solution and its effects on structural and electrochemical properties are evaluated. By using PVP in the synthesis process, the obtained sample displays a secondary plate morphology which is consisting of densely arranged primary octahedrally shaped particles. The new cathode material has a lesser degree of impurity phases, a higher discharge capacity, a superior rate capability, and a slightly better cycling performance than the sample synthesized without PVP. In more detail, by the use of PVP the ratio of Mn3+ to Mn4+ in the final product decreases from 20.8 to 9.2%. The initial discharge capacity at 0.1 C exhibits an increase of about 14%. The normalized capacity at 20 C is 84.1% instead of 67.0%. A slightly improved cycling performance with the capacity retention increase from 93.8 to 97.9% could be observed as well.

  2. Core-Shell Silver/Polymeric Nanoparticles-Based Combinatorial Therapy against Breast Cancer In-vitro

    PubMed Central

    Elbaz, Nancy M.; Ziko, Laila; Siam, Rania; Mamdouh, Wael

    2016-01-01

    The current study aimed at preparing AgNPs and three different core-shell silver/polymeric NPs composed of Ag core and three different polymeric shells: polyvinyl alcohol (PVA), polyethylene glycol (PEG) and polyvinylpyrrolidone (PVP). Thereafter, the core/shell NPs were loaded with a chemotherapeutic agent doxorubicin (DOX). Finally, the cytotoxic effects of the different core-shell Ag/polymeric NPs-based combinatorial therapeutics were tested in-vitro against breast cancer (MCF-7) and human fibroblast (1BR hTERT) cell lines. AgNPs, Ag/PVA and Ag/PVP NPs were more cytotoxic to MCF-7 cells than normal fibroblasts, as well as DOX-Ag, DOX-Ag/PVA, DOX-Ag/PEG and DOX-Ag/PVP nanocarriers (NCs). Notably, low dosage of core-shell DOX-loaded Ag/polymeric nanocarriers (NCs) exhibited a synergic anticancer activity, with DOX-Ag/PVP being the most cytotoxic. We believe that the prepared NPs-based combinatorial therapy showed a significant enhanced cytotoxic effect against breast cancer cells. Future studies on NPs-based combinatorial therapy may aid in formulating a novel and more effective cancer therapeutics. PMID:27491622

  3. Preparation and characterization of polymer nanocomposites coated magnetic nanoparticles for drug delivery applications

    NASA Astrophysics Data System (ADS)

    Prabha, G.; Raj, V.

    2016-06-01

    In the present research work, the anticancer drug 'curcumin' is loaded with Chitosan (CS)-polyethylene glycol (PEG)-polyvinylpyrrolidone (PVP) (CS-PEG-PVP) polymer nanocomposites coated with superparamagnetic iron oxide (Fe3O4) nanoparticles. The system can be used for targeted and controlled drug delivery of anticancer drugs with reduced side effects and greater efficiency. The prepared nanoparticles were characterized by Fourier transmission infrared spectroscopy (FTIR), vibrating sample magnetometry (VSM), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Curcumin drug loaded Fe3O4-CS, Fe3O4-CS-PEG and Fe3O4-CS-PEG-PVP nanoparticles exhibited the mean particle size in the range of 183-390 nm with a zeta potential value of 26-41 mV as measured using Malvern Zetasizer. The encapsulation efficiency, loading capacity and in-vitro drug release behavior of curcumin drug loaded Fe3O4-CS, Fe3O4-CS-PEG and Fe3O4-CS-PEG-PVP nanoparticles were studied using UV spectrophotometer. Besides, the cytotoxicity of the prepared nanoparticles using MTT assay was also studied. The curcumin drug release was examined at different pH medium and it was proved that the drug release depends upon the pH medium in addition to the nature of matrix.

  4. Engineering of air-stable Fe/C/Pd composite nanoparticles for environmental remediation applications

    NASA Astrophysics Data System (ADS)

    Haham, Hai; Grinblat, Judith; Sougrati, Moulay-Tahar; Stievano, Lorenzo; Margel, Shlomo

    2015-09-01

    The present manuscript presents a convenient method for the synthesis of iron/carbon (Fe/C) nanoparticles (NPs) coated with much smaller Pd NPs for the removal of halogenated organic pollutants. For this purpose, iron oxide/polyvinylpyrrolidone (IO/PVP) NPs were first prepared by the thermal decomposition of ferrocene mixed with PVP at 350 °C under an inert atmosphere. IO,Fe/C and Fe/C NPs coated with graphitic and amorphous carbon layers were then produced by annealing the IO/PVP NPs at 500 and 600 °C, respectively, under an inert atmosphere. The effect of the annealing temperature on the chemical composition, shape, crystallinity, surface area and magnetic properties of the IO/PVP, IO,Fe/C and Fe/C NPs has been elucidated. Air-stable Fe/C/Pd NPs were produced by mixing the precursor palladium acetate with the air-stable Fe/C NPs in ethanol. The obtained Fe/C/Pd NPs demonstrated significantly higher environmental activity than the Fe/C NPs on eosin Y, a model halogenated organic pollutant. The environmental activity of the Fe/C/Pd NPs also increased with their increasing Pd content.

  5. Synthesis of highly monodispersed Ga-soc-MOF hollow cubes, colloidosomes and nanocomposites.

    PubMed

    Cai, Xuechao; Deng, Xiaoran; Xie, Zhongxi; Bao, Shouxin; Shi, Yanshu; Lin, Jun; Pang, Maolin; Eddaoudi, Mohamed

    2016-08-01

    Ga-soc-MOF hollow cubes with an average size of about 300 nm were prepared by a polyvinylpyrrolidone (PVP) assisted acid etching process. Colloidosomes with sizes of around 5-10 μm composed of single-layer tetrakaidecahedron building blocks (BBs) were synthesized for the first time. Au@Ga-soc-MOF nanocomposites with excellent catalytic properties were obtained. PMID:27424486

  6. Compatible Blends of Zein and Polyvinylpyrrolidone

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Blends of zein and polyvinylpyrrolidone (PVP) were compared based on their tensile properties, thermal properties and morphology. Zein was blended with polyvinylpyrrolidone of varying molecular weights (10,000, 55,000 and 1,300,000 MW) and films were cast from ethanol solutions. Films cast using t...

  7. A room-temperature process for fabricating a nano-Pt counter electrode on a plastic substrate for efficient dye-sensitized cells

    NASA Astrophysics Data System (ADS)

    Hsieh, Tsung-Yu; Wei, Tzu-Chien; Zhai, Peng; Feng, Shien-Ping; Ikegami, Masashi; Miyasaka, Tsutomu

    2015-06-01

    We present a method for depositing polyvinylpyrrolidone-capped platinum nanoparticles (PVP-nPt) on a plastic substrate as the counter electrode (CE) for dye-sensitized cells. This method was implemented using a modified two-step dip-coating process performed under ambient conditions. In particular, a short UV-ozone exposure period was adopted to replace conventional annealing, rendering the whole process feasible for plastic substrates. The surfactant required for deposition was confirmed by analyzing a Fourier transform infrared spectroscopy spectrum; however, we discovered that the surfactant jeopardized charge transfer between the PVP-nPt CE and the substrate. Furthermore, the UV-ozone treatment efficiently decomposed the surfactant, and the electrochemical-catalytic property improved considerably. When the CE was combined with a dye-sensitized photoanode fabricated on a plastic substrate, the power conversion efficiency (PCE) reached 6.24%. To further prove that the PCE is limited by the plastic photoanode instead of the proposed plastic PVP-nPt CE, a photoanode fabricated on FTO glass and the proposed plastic PVP-nPt CE with a PCE of 8.80% was demonstrated. Finally, thermal aging (conducted at 60 °C, 1000 h) test on this device indicated excellent durability, and the PCE was only 1% lower than its initial value.

  8. Direct crystallization of perovskite phase in PMN-PT thin films prepared by polyvinylpyrrolidone modified sol-gel processing and their properties

    SciTech Connect

    Du, Z.H.; Zhang, T.S.; Zhu, M.M.; Ma, J.

    2009-07-15

    A modified sol-gel processing has been developed by using polyvinylpyrrolidone (PVP) as modifier and lead nitrate as lead source to synthesize (1-x)Pb(Mg{sub 1/3},Nb{sub 2/3})O{sub 3}-xPbTiO{sub 3} (PMN-PT) thin films with x=0.23-0.43. With PVP additions, perovskite phase could directly crystallize from amorphous films at the temperature as low as 430 deg. C via bypassing the metastable phase-pyrochlore and crystallinity was significantly enhanced. The PVP addictives have been optimized with molecular weight <630 K and the ratio of PVP monomer/PMN-PT at 0.25-1.0. XPS analysis indicates that the chemical states of the elements in the well-crystallized PMN-PT films are close to the literature data for the PMN-PT single crystals and the films possess highly desired electrical and optical properties. - Graphical abstract: A polyvinylpyrrolidone modified sol-gel processing was developed to synthesize pure-perovskite Pb(Mg{sub 1/3},Nb{sub 2/3})O{sub 3}-PbTiO{sub 3} films via bypassing pyrochlore phase.

  9. Core-Shell Silver/Polymeric Nanoparticles-Based Combinatorial Therapy against Breast Cancer In-vitro.

    PubMed

    Elbaz, Nancy M; Ziko, Laila; Siam, Rania; Mamdouh, Wael

    2016-01-01

    The current study aimed at preparing AgNPs and three different core-shell silver/polymeric NPs composed of Ag core and three different polymeric shells: polyvinyl alcohol (PVA), polyethylene glycol (PEG) and polyvinylpyrrolidone (PVP). Thereafter, the core/shell NPs were loaded with a chemotherapeutic agent doxorubicin (DOX). Finally, the cytotoxic effects of the different core-shell Ag/polymeric NPs-based combinatorial therapeutics were tested in-vitro against breast cancer (MCF-7) and human fibroblast (1BR hTERT) cell lines. AgNPs, Ag/PVA and Ag/PVP NPs were more cytotoxic to MCF-7 cells than normal fibroblasts, as well as DOX-Ag, DOX-Ag/PVA, DOX-Ag/PEG and DOX-Ag/PVP nanocarriers (NCs). Notably, low dosage of core-shell DOX-loaded Ag/polymeric nanocarriers (NCs) exhibited a synergic anticancer activity, with DOX-Ag/PVP being the most cytotoxic. We believe that the prepared NPs-based combinatorial therapy showed a significant enhanced cytotoxic effect against breast cancer cells. Future studies on NPs-based combinatorial therapy may aid in formulating a novel and more effective cancer therapeutics. PMID:27491622

  10. Optical properties of Ag nanoparticle-polymer composite film based on two-dimensional Au nanoparticle array film

    PubMed Central

    2014-01-01

    The nanocomposite polyvinyl pyrrolidone (PVP) films containing Ag nanoparticles and Rhodamine 6G are prepared on the two-dimensional distinctive continuous ultrathin gold nanofilms. We investigate the optical properties and the fluorescence properties of silver nanoparticles-PVP polymer composite films influenced by Ag nanoparticles and Au nanoparticles. Absorption spectral analysis suggests that the prominently light absorption in Ag nanowire/PVP and Ag nanowire/PVP/Au film arises from the localized surface plasmon resonance of Ag nanowire and Au nanofilm. The enhanced fluorescence is observed in the presence of Ag nanowire and Au nanofilm, which is attributed to the excitation of surface plasmon polariton resonance of Ag nanowire and Au nanofilm. The gold nanofilm is proven to be very effective fluorescence resonance energy transfer donors. The fabricated novel structure, gold ultrathin continuous nanofilm, possesses high surface plasmon resonance properties and prominent fluorescence enhancement effect. Therefore, the ultrathin continuous gold nanofilm is an active substrate on nanoparticle-enhanced fluorescence. PMID:24685186

  11. Optical properties of Ag nanoparticle-polymer composite film based on two-dimensional Au nanoparticle array film.

    PubMed

    Wang, Long-De; Zhang, Tong; Zhang, Xiao-Yang; Song, Yuan-Jun; Li, Ruo-Zhou; Zhu, Sheng-Qing

    2014-01-01

    The nanocomposite polyvinyl pyrrolidone (PVP) films containing Ag nanoparticles and Rhodamine 6G are prepared on the two-dimensional distinctive continuous ultrathin gold nanofilms. We investigate the optical properties and the fluorescence properties of silver nanoparticles-PVP polymer composite films influenced by Ag nanoparticles and Au nanoparticles. Absorption spectral analysis suggests that the prominently light absorption in Ag nanowire/PVP and Ag nanowire/PVP/Au film arises from the localized surface plasmon resonance of Ag nanowire and Au nanofilm. The enhanced fluorescence is observed in the presence of Ag nanowire and Au nanofilm, which is attributed to the excitation of surface plasmon polariton resonance of Ag nanowire and Au nanofilm. The gold nanofilm is proven to be very effective fluorescence resonance energy transfer donors. The fabricated novel structure, gold ultrathin continuous nanofilm, possesses high surface plasmon resonance properties and prominent fluorescence enhancement effect. Therefore, the ultrathin continuous gold nanofilm is an active substrate on nanoparticle-enhanced fluorescence. PMID:24685186

  12. Adsorption of heavy metal ions by immobilized phytic acid

    SciTech Connect

    Tsao, G.T.; Zheng, Yizhou; Lu, J.; Gong, Cheng S.

    1997-12-31

    Phytic acid (myoinositol hexaphosphate) or its calcium salt, phytate, is an important plant constituents. It accounts for up to 85% of total phosphorus in cereals and legumes. Phytic acid has 12 replaceable protons in the phytic molecule rendering it the ability to complex with multivalent cations and positively charged proteins. Poly 4-vinyl pyridine (PVP) and other strong-based resins have the ability to adsorb phytic acid. PVP has the highest adsorption capacity of 0.51 phytic acid/resins. The PVP resin was used as the support material for the immobilization of phytic acid. The immobilized phytic acid can adsorb heavy metal ions, such as cadmium, copper, lead, nickel, and zinc ions, from aqueous solutions. Adsorption isotherms of the selected ions by immobilized phytic acid were conducted in packed-bed column at room temperature. Results from the adsorption tests showed 6.6 mg of Cd{sup 2+}, 7 mg of Cu{sup 2+}, 7.2 mg of Ni{sup 2+}, 7.4 mg of Pb{sup 2+}, and 7.7 mg of Zn{sup 2+} can be adsorbed by each gram of PVP-phytic acid complex. The use of immobilized phytic acid has the potential for removing metal ions from industrial or mining waste water. 15 refs., 7 figs., 2 tabs.

  13. Electrolyte-induced collapse of a polyelectrolyte brush

    NASA Astrophysics Data System (ADS)

    Biesalski, M.; Johannsmann, D.; Rühe, J.

    2004-05-01

    We have investigated the electrolyte-induced collapse of a polyelectrolyte brush covalently attached to a planar solid surface. Positively charged poly-4-vinyl [N-methyl-pyridinium] (MePVP) brushes were prepared in situ at the surface by free radical chain polymerization using a surface-immobilized initiator monolayer ("grafting from" technique) and 4-vinylpyridine as the monomer, followed by a polymer-analogous quaternization reaction. The height of the brushes was measured as a function of the external salt concentration via multiple-angle null ellipsometry. As predicted by mean-field theory, the height of the MePVP brushes remains unaffected by the addition of low amounts of external salt. At higher salt concentrations the brush height decreases. The extent to which the brush shrinks strongly depends on the nature of the salt present in the environment. MePVP brushes collapse to almost the dry layer thickness upon the addition of potassium iodide to a contacting aqueous medium. In contrast, the collapse of MePVP brushes having bromide or chloride counterions is much less pronounced. These brushes remain in a highly swollen state even after large amounts of salt have been added to the solution.

  14. Photo-induced exciton generation in polyvinylpyrrolidone encapsulated Ag2S core-shells: Electrochemical deposition, regular shape and high order of particle size distribution

    NASA Astrophysics Data System (ADS)

    Mukherjee, Nillohit; Jana, Sumanta; Gopal Khan, Gobinda; Mondal, Anup

    2012-12-01

    Visible light induced frequency switching behavior, exhibited by the electrochemically deposited thin films of polyvinylpyrrolidone (PVP) encapsulated Ag2S nanosphere (core-shell) is shown here. A low frequency (˜40 Hz) pulse was found to be generated upon illumination with 1 Sun due to excitonic transition, which also showed good switching behavior with the "on" and "off" state of the light. Capping of the semiconductor surface by a polymer like PVP reduces the surface states and thus lowers the built in barrier height and the width of depletion region. So, the number of photo generated but non recombining electron-hole pairs (excitons) increases, which put their signature in some unique physical properties like increase in photoluminescence (PL) intensity, light induced frequency switching behavior due to free exciton generation, etc. Here, the depositions were carried out on indium tin oxide coated glass substrates from an aqueous solution of AgNO3, thioacetamide, and PVP. The films were structurally characterized using high resolution X-ray diffraction, field emission scanning electron microscopy, and high resolution transmission electron microscopic techniques. The deposited particles were regular in shape with significantly high order of size distribution. Furrier transform infrared spectroscopy confirmed the presence of PVP as the encapsulating agent. Optical characterization, viz., UV - vis - NIR and NIR-PL revealed noteworthy amount of NIR emission from the deposited material.

  15. Online Coupling of Lab-on-Valve Format to Amperometry Based on Polyvinylpyrrolidone-Doped Carbon Paste Electrode and Its Application to the Analysis of Morin

    PubMed Central

    Wang, Yang; Yao, Guojun; Tang, Jie; Yang, Chun; Xu, Qin; Hu, Xiaoya

    2012-01-01

    The potential capabilities and analytical performance of lab-on-valve (LOV) manifold as a front end to amperometry have been explored for the on-line determination of morin. Meanwhile, the electrochemical behaviors of morin were investigated based on polyvinylpyrrolidone- (PVP-) doped carbon paste electrode (CPE), which found that PVP can significantly improve its oxidation peak current. The excellent amperometric current response was achieved when the potential difference (ΔE) of 0.6 V was implemented in pH 6.5 phosphate buffer solution (PBS) that served as the supporting electrolyte. A well-defined oxidation peak has been obtained in studies using PVP as a modifier of CPE based on the oxidation of morin. The present work introduces the LOV technique as a useful tool for amperometric measurement, documents advantages of using programmable flow, and outlines means for miniaturization of assays on the basis of PVP modified CPE. The proposed method was applied successfully to the determination of morin in real samples, and the spiked recoveries were satisfactory. PMID:22567551

  16. Facile synthesis of S–Ag nanocomposites and Ag2S short nanorods by the interaction of sulfur with AgNO3 in PEG400

    NASA Astrophysics Data System (ADS)

    Zhang, Yan-Li; Xie, Xin-Yuan; Liang, Ming; Xie, Shu-Ming; Chen, Jie-Mei; Zheng, Wen-Jie

    2016-06-01

    A facile, eco-friendly and inexpensive method to prepare Ag2S short nanorods and S–Ag nanocomposites using sublimed sulfur, AgNO3, PVP and PEG400 was studied. According to x-ray diffraction and scanning electron microscopy of the Ag2S, the products are highly crystalline and pure Ag2S nanorods with diameters of 70–160 nm and lengths of 200–360 nm. X-ray diffraction of the S–Ag nanocomposites shows that we obtained cubic Ag and S nanoparticles. Transmission electron microscopy shows that the molar ratio of PVP to Ag+ plays an important role in controlling the size and morphology of the S–Ag nanocomposites. When the molar ratio of PVP to Ag+ was 10:1, smaller sizes, better dispersibility and narrower distribution of S–Ag nanocomposites with diameters of 10–40 nm were obtained. The formation mechanism of the S–Ag nanocomposites was studied by designing a series of experiments using ultraviolet–visible measurement, and it was found that S nanoparticles are produced first and act as seed crystals; then Ag+ becomes Ag nanocrystals on the surfaces of the S nanoparticles by the reduction of PVP. PEG400 acts as a catalyzer, accelerating the reaction rate, and protects the S–Ag nanocomposites from reacting to produce Ag2S. The antimicrobial experiments show that the S–Ag nanocomposites have greater antimicrobial activity on Staphylococcus aureus, Aspergillus niger and blue mold than Ag nanoparticles.

  17. Relationship between Plasma D-Dimer Concentration and Three-Dimensional Ultrasound Placental Volume in Women at Risk for Placental Vascular Diseases: A Monocentric Prospective Study

    PubMed Central

    Fanget, Cécile; Chauleur, Céline; Stadler, Amandine; Presles, Emilie; Varlet, Marie-Noëlle; Gris, Jean-Christophe

    2016-01-01

    Introduction The aim of this study was to correlate placental volumes deduced from three-dimensional ultrasound and virtual organ computer-aided analysis (VOCAL) software with systemic concentrations of D-dimer and soluble endothelial protein C receptor (sEPCR). Methods This was a monocentric experimental prospective study conducted from October 2008 to July 2009. Forty consecutive patients at risk of placental vascular pathology (PVP) recurrence or occurrence were included. Placental volumes were systematically measured three times (11–14, 16–18 and 20–22 weeks of gestation (WG)) by two independent sonographers. D-dimers and sEPCR plasma concentrations were measured using ELISA kits (Enzyme Linked ImmunoSorbent Assay). Results Eleven patients had a PVP. The plasma D-dimer level was positively correlated with placental volume (r = 0.45, p < 0.001). A smaller placental volume and placental quotient was evidenced in women who developed a PVP at the three gestational ages, and the difference was more pronounced during the third exam (20 WG). No obvious correlation could be demonstrated between the development of a PVP and the levels of D-dimer and sEPCR. There was no significant difference in the values of placental volumes measured by the two sonographers. Conclusion The placenta growth could be a major determinant of the elevation of D-dimer during pregnancy. Consideration of placental volume could allow for modulation of the D-dimer concentrations for restoring their clinical interest. PMID:27294274

  18. Microwave-assisted polyol synthesis of PtCu/carbon nanotube catalysts for electrocatalytic oxygen reduction

    NASA Astrophysics Data System (ADS)

    El-Deeb, Heba; Bron, Michael

    2015-02-01

    PtCu/CNT alloy electrocatalysts were prepared by microwave assisted polyol synthesis. The influence of preparation pH and the presence of polyvinylpyrrolidone (PVP) as stabilizer on catalysts nanostructure and activity towards electrocatalytic oxygen reduction was evaluated. The catalysts were alloyed at 400-600 °C for 6 h in reductive atmosphere, and characterized by TEM and XRD. The XRD patterns display a positive shift in 2θ of the Pt 111 peak, which is a good evidence for Pt-Cu alloy formation. Alloy nanoparticles already form at temperatures as low as 400 °C. Highly agglomerated PtCu nanoparticles were obtained in the absence of PVP while PVP addition resulted in dispersed and uniform nanoparticles with a mean particle size of 3.7 nm. Such small particles are a result of the considerably low temperature used during the heat treatment/alloying step. However, while Pt is nearly completely deposited on the CNTs, only smaller fractions of Cu are found in the final catalyst. A high extent of agglomeration was also noticed when the pH during polyol synthesis was increased, which is attributed to Cu-hydroxides precipitation. Pt-Cu core shell catalysts were obtained after voltammetric dealloying. Catalyst prepared at higher pH in the presence of PVP display the highest electrocatalytic activity.

  19. A flap-type hydrogel actuator with fast responses to temperature

    NASA Astrophysics Data System (ADS)

    Zhang, Yaopeng; Kato, Shinji; Anazawa, Takanori

    2007-12-01

    A novel temperature-sensitive hydrogel with fast deswelling and swelling rates was prepared from an N-isopropylacrylamide monomer mixture with poly(vinylpyrrolidone) (PVP) and its lightly crosslinked counterpart (so-called polyvinyl-polypyrrolidone, PVPP). The PVP worked as a porogen for the polymerization-induced phase separation of the hydrogel while the PVPP microgels were used as a pore-structure modifier. The hydrogel, in the form of a layer, was laminated with an acrylic resin layer to make a temperature-sensitive flap which can work as a bimetallic-like actuator with fast responses. Owing to the different deswelling/swelling ratios of the two layers, the smart flap bent in opposite directions in water at different temperatures. The switching temperature, at which the flap changed its bending direction, was adjusted by applying different ratios of PVP/PVPP in the hydrogel precursors. Dynamic results show that the flap with a hydrogel layer modified by PVP/PVPP required only several seconds to bend to its equilibrium states in both directions. No obvious performance loss was found after numerous heating-cooling cycles and the processes of drying and recovery.

  20. Regulation of biphasic drug release behavior by graphene oxide in polyvinyl pyrrolidone/poly(ε-caprolactone) core/sheath nanofiber mats.

    PubMed

    Yu, Hui; Yang, Peng; Jia, Yongtang; Zhang, Yumei; Ye, Qiuying; Zeng, Simin

    2016-10-01

    One of the key issues for drug delivery systems is to develop a drug carrier with a time-programmed, biphasic release behavior. Using vancomycin hydrochloride (VAN) as a model drug, polyvinyl pyrrolidone (PVP) blended with graphene oxide (GO) sheets as the core matrix, and poly(ε-caprolactone) (PCL) as the sheath polymer, core/sheath PVP/PCL nanofiber mats were fabricated via a coaxial electrospinning process. We hypothesized that the addition of GO sheets would lead to their molecular interactions with VAN molecules, thereby adjusting the VAN release behavior. Field emission scanning electron microscopy and transmission electron microscopy of the fiber mats revealed their nanofibrous structure and clear core/sheath boundary. Raman analysis demonstrated the presence of GO sheets in the PVP/PCL nanofiber mats. Fourier transform infrared spectroscopy indicated the formation of hydrogen bonds between GO sheets and VAN molecules. In vitro studies showed that the PVP/PCL nanofiber mats were biocompatible, despite the addition of GO sheets, and exhibited typical biphasic drug release profiles, which were tailored by adjusting the content of GO sheets. Furthermore, an antimicrobial test showed different antimicrobial activities of the medicated nanofiber mats, depending on the GO content. Collectively, the results of the present study provide a simple approach to obtaining time-programmed drug release profiles. PMID:27259160

  1. Video game genre as a predictor of problem use.

    PubMed

    Elliott, Luther; Golub, Andrew; Ream, Geoffrey; Dunlap, Eloise

    2012-03-01

    This study assessed how problem video game playing (PVP) varies with game type, or "genre," among adult video gamers. Participants (n=3,380) were adults (18+) who reported playing video games for 1 hour or more during the past week and completed a nationally representative online survey. The survey asked about characteristics of video game use, including titles played in the past year and patterns of (problematic) use. Participants self-reported the extent to which characteristics of PVP (e.g., playing longer than intended) described their game play. Five percent of our sample reported moderate to extreme problems. PVP was concentrated among persons who reported playing first-person shooter, action adventure, role-playing, and gambling games most during the past year. The identification of a subset of game types most associated with problem use suggests new directions for research into the specific design elements and reward mechanics of "addictive" video games and those populations at greatest risk of PVP with the ultimate goal of better understanding, preventing, and treating this contemporary mental health problem. PMID:22242785

  2. The cellular and Genomic response of rat dopaminergic neurons (N27) to coated nanosilver

    EPA Science Inventory

    This study examined if nanosilver (nanoAg) of different sizes and coatings were differentially toxic to oxidative stress-sensitive neurons. N27 rat dopaminergic neurons were exposed (0.5-5ppm) to a set of nanoAg of different sizes (10nm, 75nm) and coatings (PVP, citrate) and thei...

  3. Synthesis of PVDF ultrafiltration membranes supported on polyester fabrics for separation of organic matter from water

    NASA Astrophysics Data System (ADS)

    Mhlanga, Sabelo D.; Tshabalala, Tumelo G.; Nxumalo, Edward N.; Mamba, Bhekie B.

    2014-08-01

    Polyvinylidene flouride (PVDF) membranes supported on non-woven fabrics (NWF) of polyester are reported. The PVDF membranes were fabricated using the phase inversion method followed by modification of the active top layer of the PVDF thin film by adding polyvinylpyrolidone (PVP) into the cast solution. A PVDF resin was used with N- methyl-2-pyrrolidone (NMP) as a solvent. Sessile drop contact angle measurements and scanning electron microscopy (SEM) were used to study the physical properties of the membranes. Membrane rejection of humic acid was studied using a cross-flow membrane testing unit. The contact angle results revealed that the hydrophilicity of PVDF membranes increased as the PVP concentration was increased from 3 to 10 wt%. SEM analysis of the membranes revealed that the membrane pore sizes increased when PVP was added. AFM analysis also showed that membrane roughness changed when PVP was added. Total organic carbon (TOC) analysis of water samples spiked with humic acid was performed to test the rejection capacity of the membranes. Rejections of up to 97% were achieved for PVDF membranes supported on polyester NWF1, which had smaller thickness and higher permeability compared to polyester NWF2. The NWFs provided the high strength required for the membranes despite the modifications done on the PDVF surface and microstructure.

  4. [Immunodepressive properties of diethyleneimine benzoquinone-containing polyvinylpyrrolidone complexes].

    PubMed

    Kostadinov, D; Popov, D

    1978-01-01

    The authors examined the changes, which occurred in the weight of lymphoid organs (thymus, spleen, and lymph nodes) and titre of serum hemagglutinines against sheep erythrocytes in mice BAIB/c under the influence of treatment with diethyleniminbenzochinon and some of its complexes with polyvinylpirolidon (PVP). The ratio of the substances composing the complexes (in mg per 1000 mg of complex) was as followed: DEiBx- PVP complex NoI-340:660; DEiBx-PVP complex No2-200:800; DEiBx-PVP-Uracyl complex No3-250:500:250. There was a sharp reduction of the weight of lymphoid organs in mice, treated with DEiBx, singly or in the form of complexes NoI and No2 in comparison with the control nontreated mice or treated with complex No3. This effect was more manifested after treatment with DEiBx during the same regimen (0.8 mg/kg of body weight daily for 5 days). The ability of the treated animals to react to immunization with sheep erythrocytes practicaly was not impaired during the treatment with complexes No2 and No3 or the damage was slight (complex NoI) in contrast to the treatment with DEiBx. PMID:658000

  5. Peak-valley-peak pattern of histone modifications delineates active regulatory elements and their directionality

    PubMed Central

    Pundhir, Sachin; Bagger, Frederik O.; Lauridsen, Felicia B.; Rapin, Nicolas; Porse, Bo T.

    2016-01-01

    Formation of nucleosome free region (NFR) accompanied by specific histone modifications at flanking nucleosomes is an important prerequisite for enhancer and promoter activity. Due to this process, active regulatory elements often exhibit a distinct shape of histone signal in the form of a peak-valley-peak (PVP) pattern. However, different features of PVP patterns and their robustness in predicting active regulatory elements have never been systematically analyzed. Here, we present PARE, a novel computational method that systematically analyzes the H3K4me1 or H3K4me3 PVP patterns to predict NFRs. We show that NFRs predicted by H3K4me1 and me3 patterns are associated with active enhancers and promoters, respectively. Furthermore, asymmetry in the height of peaks flanking the central valley can predict the directionality of stable transcription at promoters. Using PARE on ChIP-seq histone modifications from four ENCODE cell lines and four hematopoietic differentiation stages, we identified several enhancers whose regulatory activity is stage specific and correlates positively with the expression of proximal genes in a particular stage. In conclusion, our results demonstrate that PVP patterns delineate both the histone modification landscape and the transcriptional activities governed by active enhancers and promoters, and therefore can be used for their prediction. PARE is freely available at http://servers.binf.ku.dk/pare. PMID:27095194

  6. Study of wound dressing structure and hydration/dehydration properties

    NASA Astrophysics Data System (ADS)

    Lugão, A. B.; Machado, L. D. B.; Miranda, L. F.; Alvarez, M. R.; Rosiak, J. M.

    1998-06-01

    Hydrogels manufactured by radio-induced crosslinking and simultaneous sterilisation of hydrogels of PVP, PEG and agar, according to the Rosiak method, have many desirable properties for using as wound dressings. However, some properties need to be improved or better controlled. The membranes need to be strong enough to be freely used. Another important property to be controlled is the capacity of absorption of exudate and the kinetics of drying. Therefore, it was necessary to understand the role of main parameters (agar, PVP, PEG concentration and dose) in the structure of the net and in the hydration and dehydration properties. The structure of the membranes was studied by sol analysis and the hydrating/dehydrating properties were studied by isothermal thermogravimetric analysis. The gel content for all samples were always in agreement with expected values considering that only PVP undergoes crosslinking. The hydrating and dehydration results did not show variation with the tested parameters. It was concluded that the network was solely composed of crosslinked PVP plasticezed by the other compounds. The properties of hydration/dehydration is related rather to diffusion than to capillarity or osmose and to the chemical retention of water in the polymeric matrix.

  7. Treatment of laundry wastewater using polyethersulfone/polyvinylpyrollidone ultrafiltration membranes.

    PubMed

    Sumisha, A; Arthanareeswaran, G; Lukka Thuyavan, Y; Ismail, A F; Chakraborty, S

    2015-11-01

    In this study, laundry wastewater filtration was studied using hydrophilic polyvinylpyrollidone (PVP) modified polyethersulfone (PES) ultrafiltration membranes. The performances of PES/PVP membranes were assessed using commercial PES membrane with 10kDa in ultrafiltration. Operating parameters The influence of transmembrane pressure (TMP) and stirring speed on laundry wastewater flux was investigated. A higher permeate flux of 55.2L/m(2)h was obtained for modified PES membrane with high concentration of PVP at TMP of 500kPa and 750rpm of stirring speed. The separation efficiencies of membranes were also studied with respect to chemical oxygen demand (COD), total dissolved solids (TDS), turbidity and conductivity. Results showed that PES membrane with 10% of PVP had higher permeate flux, flux recovery and less fouling when compared with other membranes. Higher COD and TDS rejection of 88% and 82% were also observed for modified membranes due to the improved surface property of membranes. This indicated that modified PES membranes are suitable for the treatment of surfactant, detergent and oil from laundry wastewater. PMID:25890841

  8. Solvent-shift strategy to identify suitable polymers to inhibit humidity-induced solid-state crystallization of lacidipine amorphous solid dispersions.

    PubMed

    Sun, Mengchi; Wu, Chunnuan; Fu, Qiang; Di, Donghua; Kuang, Xiao; Wang, Chao; He, Zhonggui; Wang, Jian; Sun, Jin

    2016-04-30

    The solvent-shift strategy was used to identify appropriate polymers that inhibit humidity-induced solid-state crystallization of amorphous solid dispersions (ASDs). Lacidipine with the polymers, PVP-K30, HPMC-E5 or Soluplus, were combined to form amorphous solid dispersions prepared by solvent evaporation. The formulations were characterized by differential scanning calorimetry (DSC), powder X-ray diffraction (PXRD), and Fourier-transform infrared spectroscopy (FT-IR) and were subjected to in vitro dissolution testing. The moisture had a significant impact on the amount dissolved for the solid dispersions. Molecular docking studies established that hydrogen bonding was critical for the stabilization of the solid dispersions. The rank order of the binding energy of the drug-polymer association was Soluplus (-6.21kcal/mol)>HPMC-E5 (-3.21kcal/mol)>PVP-K30 (-2.31kcal/mol). PVP-K30 had the highest water uptake among the polymers, as did ASD system of lacidipine-PVP-K30 ASDs. In the Soluplus ASDs, with its strong drug-polymer interactions and low water uptake, moisture-induced solid-state crystallization was not observed. PMID:26869398

  9. Effect of osmotic pressure on ganglioside-cholesterol-DOPC lipid mixture

    NASA Astrophysics Data System (ADS)

    Onai, Teruaki; Hirai, Mitsuhiro

    2007-10-01

    By means of small-angle X-ray scattering (SAXS) method, we have studied the structure of the lipid mixtures of monosialoganglioside (GMI)-cholesterol-dioleoyl-phosphatidylcholine (DOPC) system as a model of lipid raft. The samples were small uni-lamellar vesicle (SUV) except for GMI sample. The osmotic pressure was changed with varying the polyvinylpyrrolidone (PVP) concentration in the range from 0 to 25 % w/w. The increase of the PVP concentration is known to reduce the lamellar spacing due to the increase of the osmotic pressure. On the other hand the polar head region of GMI was shown to be highly hydrophilic by the presence of oligosaccharide chain containing one sialic acid residue. In the cases of the GMI micelle and GMI-cholesterol SUV the presence of PVP affects little on those aggregate structures. In the case of the SUVs of cholesterol-DOPC the stacking of the bilayers was induced with the increase of PVP concentration, especially at high cholesterol content. In the case of the SUVs of GMI-cholesterol-DOPC the multi-lamellar stacking was suppressed, but a minor change of the SUV structure was induced. The present results suggest that the coexistence of GMI and cholesterol affords the lipid bilayer a resistance to the osmotic stress and avoids a multi-layered stacking.

  10. Robotic-Assisted Removal of Intracardiac Cement After Percutaneous Vertebroplasty.

    PubMed

    Molloy, Thomas; Kos, Allison; Piwowarski, Amy

    2016-05-01

    Percutaneous vertebroplasty (PVP) is an increasingly common intervention, and complications resulting from embolization are increasingly observed. We report a case of polymethyl methacrylate (PMMA) embolization resulting in cardiac complications in a frail patient, which was managed with endoscopic robotic-assisted removal of the embolized material. PMID:27106432

  11. Value of MR histogram analyses for prediction of microvascular invasion of hepatocellular carcinoma

    PubMed Central

    Huang, Ya-Qin; Liang, He-Yue; Yang, Zhao-Xia; Ding, Ying; Zeng, Meng-Su; Rao, Sheng-Xiang

    2016-01-01

    Abstract The objective is to explore the value of preoperative magnetic resonance (MR) histogram analyses in predicting microvascular invasion (MVI) of hepatocellular carcinoma (HCC). Fifty-one patients with histologically confirmed HCC who underwent diffusion-weighted and contrast-enhanced MR imaging were included. Histogram analyses were performed and mean, variance, skewness, kurtosis, 1th, 10th, 50th, 90th, and 99th percentiles were derived. Quantitative histogram parameters were compared between HCCs with and without MVI. Receiver operating characteristics (ROC) analyses were generated to compare the diagnostic performance of tumor size, histogram analyses of apparent diffusion coefficient (ADC) maps, and MR enhancement. The mean, 1th, 10th, and 50th percentiles of ADC maps, and the mean, variance. 1th, 10th, 50th, 90th, and 99th percentiles of the portal venous phase (PVP) images were significantly different between the groups with and without MVI (P <0.05), with area under the ROC curves (AUCs) of 0.66 to 0.74 for ADC and 0.76 to 0.88 for PVP. The largest AUC of PVP (1th percentile) showed significantly higher accuracy compared with that of arterial phase (AP) or tumor size (P <0.001). MR histogram analyses—in particular for 1th percentile for PVP images—held promise for prediction of MVI of HCC. PMID:27368028

  12. Visualization of Individual Single-Walled Carbon Nanotubes by Fluorescent Polymer Wrapping

    PubMed Central

    Moore, Valerie C.; Baskin, David S.; Smalley, Richard E.

    2007-01-01

    Manipulating optical properties of single-walled nanotubes (SWNTs) is necessary for the development of nanoscale optical devices and probes for biomedical research. In life sciences it will make possible the direct observation of SWNTs inside living cells using optical microscopes. In the nanotechnology field it will enable the development of nanosensors with fluorescent reporting. However, the direct fluorescent labeling of SWNTs is obstructed by their strong light quenching qualities. Besides, chemical functionalization of SWNTs needed for the covalent attachment of fluorescent dyes could change favorable properties of nanotubes. Here we report that optical properties of SWNTs can be manipulated without their covalent modification by wrapping them with fluorescently labeled polymer poly(vinylpyrrolidone) (PVP-1300). Fluorescent PVP-1300 forms a monomolecular ~2.5 nm thick layer coiling around individual SWNTs and nanotube bundles. PVP casing is fluorescent although it is only several nanometers thick. This makes individual SWNTs observable by a fluorescent microscope. The spare polymer strands left over after wrapping around the relatively shorter nanotubes form junctions between SWNTs tying them together into new configurations, primarily Y- and Ψ-type junctions. The ability to use a single fluorescent polymer strand to fasten nanotubes together can be useful in assembly of nanotube-made devices. In PVP-covered SWNTs multiple fluorophores are attached to each single nanotube making them unique composite fluorophores attractive as parts of biological fluorescent probes and in the development of the new materials in photonics and nanotechnology. PMID:16089489

  13. Preparation, property of the complex of carboxymethyl chitosan grafted copolymer with iodine and application of it in cervical antibacterial biomembrane.

    PubMed

    Chen, Yu; Yang, Yumin; Liao, Qingping; Yang, Wei; Ma, Wanfeng; Zhao, Jian; Zheng, Xionggao; Yang, Yang; Chen, Rui

    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)-I2, 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)-I2 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. PMID:27287120

  14. Visualization of individual single-walled carbon nanotubes by fluorescent polymer wrapping.

    PubMed

    Didenko, Vladimir V; Moore, Valerie C; Baskin, David S; Smalley, Richard E

    2005-08-01

    Manipulating optical properties of single-walled nanotubes (SWNTs) is necessary for the development of nanoscale optical devices and probes for biomedical research. In life sciences it will make possible the direct observation of SWNTs inside living cells using optical microscopes. In the nanotechnology field it will enable the development of nanosensors with fluorescent reporting. However, the direct fluorescent labeling of SWNTs is obstructed by their strong light quenching qualities. Besides, chemical functionalization of SWNTs needed for the covalent attachment of fluorescent dyes could change favorable properties of nanotubes. Here we report that optical properties of SWNTs can be manipulated without their covalent modification by wrapping them with fluorescently labeled polymer poly(vinylpyrrolidone) (PVP-1300). Fluorescent PVP-1300 forms a monomolecular approximately 2.5 nm thick layer coiling around individual SWNTs and nanotube bundles. PVP casing is fluorescent although it is only several nanometers thick. This makes individual SWNTs observable by a fluorescent microscope. The spare polymer strands left over after wrapping around the relatively shorter nanotubes form junctions between SWNTs tying them together into new configurations, primarily Y- and psi-type junctions. The ability to use a single fluorescent polymer strand to fasten nanotubes together can be useful in assembly of nanotube-made devices. In PVP-covered SWNTs multiple fluorophores are attached to each single nanotube making them unique composite fluorophores attractive as parts of biological fluorescent probes and in the development of the new materials in photonics and nanotechnology. PMID:16089489

  15. Antiseptics versus antibiotics in the treatment of the experimental conjunctivitis caused by Staphylococcus aureus.

    PubMed

    Behrens-Baumann, W; Begall, T

    1993-11-01

    To evaluate the effect of some antiseptics, which have fewer side effects than antibiotics, an experimental model of bacterial conjunctivitis in vivo was used. This model imitates traumatic Staphylococcus aureus conjunctivitis in the rabbit. At 48 h after infection, polyvinylpyrrolidine (PVP)-iodine, bibrocathol (Noviform, NF), ethacridine (Biseptol, BS) and bacitracin+polymyxin B+neomycin (Polyspectran, PS) were applied. NaCl served as the control. At days 2, 5, 8, 11 and 14 a photographic documentation was done, and a swab was taken every 2nd day. In achieving regression of hyperemia, the substance tested were ranked in the following order: PVP, NF, BS, PS, and NaCl. In the elimination of S. aureus, the ranking order was BS, PVP, PS, NaCl, and NF. The overall ranking was PVP, BS, PS, NF, and NaCl. However, the differences were not significant. In this standardized in vivo model of bacterial conjunctivitis, antiseptics are superior over an antibiotic in accomplishing regression of hyperemia and germ elimination. PMID:8312825

  16. Preparation and characterization of nanocomposite polymer electrolytes poly(vinylidone fluoride)/nanoclay

    NASA Astrophysics Data System (ADS)

    Rahmawati, Suci A.; Sulistyaningsih, Putro, Alviansyah Z. A.; Widyanto, Nugroho F.; Jumari, Arif; Purwanto, Agus; Dyartanti, Endah R.

    2016-02-01

    Polymer electrolytes are defined as semi solid electrolytes used as separator in lithium ion battery. Separator used as medium for transfer ions and to prevent electrical short circuits in battery cells. To obtain the optimal battery performance, separator with high porosity and electrolyte uptake is required. This can reduce the resistance in the transfer of ions between cathode and anode. The main objective of this work is to investigate the impact of different solvent (Dimethyl acetamide (DMAc), N-methyl-2-pyrrolidone (NMP) and dimethyl formamide (DMF)), pore forming agent poly(vinylpyrolidone) (PVP) and nanoclay as filler in addition of membrane using phase inversion method on the morphology, porosity, electrolyte uptake and degree of crystallinity. The membrane was prepared by the phase inversion method by adding PVP and Nanoclay using different solvents. The phase inversion method was prepared by dissolving Nanoclay and PVP in solvent for 1-2 hours, and then add the PVDF with stirring for 4 hours at 60°C. The membranes were characterized by porosity test, electrolyte uptake test, scanning electron microscope (SEM), and X-ray diffraction (XRD). The results showed that DMAc as solvent gives the highest value of porosity and electrolyte uptake. The addition of nanoclay and PVP enlarge the size of the pores and reduce the degree of crystallinity. So, the usage of DMAc as solvent is better than NMP or DMF.

  17. The Property Value Protection Program - How the Compensation Plan is Working and Evolving to Meet Changing Needs - 13149

    SciTech Connect

    Faught, Jeff; Herod, Judy; Mahabir, Alexandra

    2013-07-01

    The Property Value Protection (PVP) Program offers an innovative approach to address the risk of individual property value loss resulting from the cleanup and long-term management of historic low level radioactive waste in the Port Hope area in Southern Ontario, Canada. This cleanup is taking place through the Port Hope Area Initiative (PHAI), a federally sponsored waste remediation project. The PVP Program came into effect on October 1, 2000, having been established as a key element of the PHAI Legal Agreement between the Government of Canada and the municipalities of Port Hope and Clarington. The PVP Program was designed in direct response to the concern expressed by the agreement's two municipal signatories that protection of local property owners from the risk of property value loss was critical to their acceptance of the Port Hope and Port Granby projects. The PVP Program compensates owners of residential, commercial or industrial properties for a loss in fair market value on the sale or rental of their properties. Increased mortgage refinancing costs and expenses incurred as a result of delayed sales that can be attributed to the Port Hope Area Initiative are also compensated. (authors)

  18. Pairwise polymer blends for oral drug delivery.

    PubMed

    Marks, Joyann A; Wegiel, Lindsay A; Taylor, Lynne S; Edgar, Kevin J

    2014-09-01

    Blends of polymers with complementary properties hold promise for addressing the diverse, demanding polymer performance requirements in amorphous solid dispersions (ASDs), but we lack comprehensive property understanding for blends of important ASD polymers. Herein, we prepare pairwise blends of commercially available polymers polyvinylpyrrolidone (PVP), the cationic acrylate copolymer Eudragit 100 (E100), hydroxypropyl methylcellulose acetate succinate (HPMCAS), carboxymethyl cellulose acetate butyrate (CMCAB), hydroxypropyl methylcellulose (HPMC), and the new derivative cellulose acetate adipate propionate (CAAdP). This study identifies miscible binary blends that may find use, for example, in ASDs for solubility and bioavailability enhancement of poorly water-soluble drugs. Differential scanning calorimetry, FTIR spectroscopy, and film clarity were used to determine blend miscibility. Several polymer combinations including HPMCAS/PVP, HPMC/CMCAB, and PVP/HPMC appear to be miscible in all proportions. In contrast, blends of E100/PVP and E100/HPMC showed a miscibility gap. Combinations of water-soluble and hydrophobic polymers like these may permit effective balancing of ASD performance criteria such as release rate and polymer-drug interaction to prevent nucleation and crystal growth of poorly soluble drugs. Miscible polymer combinations described herein will enable further study of their drug delivery capabilities, and provide a potentially valuable set of ASD formulation tools. PMID:24823790

  19. Labeling transplanted mice islet with polyvinylpyrrolidone coated superparamagnetic iron oxide nanoparticles for in vivo detection by magnetic resonance imaging

    NASA Astrophysics Data System (ADS)

    Huang, Hai; Xie, Qiuping; Kang, Muxing; Zhang, Bo; Zhang, Hui; Chen, Jin; Zhai, Chuanxin; Yang, Deren; Jiang, Biao; Wu, Yulian

    2009-09-01

    Superparamagnetic iron oxide nanoparticles (SPIO) are emerging as a novel probe for noninvasive cell tracking with magnetic resonance imaging (MRI) and have potential wide usage in medical research. In this study, we have developed a method using high-temperature hydrolysis of chelate metal alkoxide complexes to synthesize polyvinylpyrrolidone coated iron oxide nanoparticles (PVP-SPIO), as a biocompatible magnetic agent that can efficiently label mice islet β-cells. The size, crystal structure and magnetic properties of the as-synthesized nanoparticles have been characterized. The newly synthesized PVP-SPIO with high stability, crystallinity and saturation magnetization can be efficiently internalized into β-cells, without affecting viability and function. The imaging of 100 PVP-SPIO-labeled mice islets in the syngeneic renal subcapsular model of transplantation under a clinical 3.0 T MR imager showed high spatial resolution in vivo. These results indicated the great potential application of the PVP-SPIO as an MRI contrast agent for monitoring transplanted islet grafts in the clinical management of diabetes in the near future.

  20. Successive interaction of pairs of soluble organics with nanosilica in aqueous media.

    PubMed

    Gun'ko, V M; Zarko, V I; Voronin, E F; Goncharuk, E V; Andriyko, L S; Guzenko, N V; Nosach, L V; Janusz, W

    2006-08-01

    Successive interaction of different pairs of water-soluble polymers (poly(ethylene glycol) (PEG), poly(vinyl pyrrolidone) (PVP), poly(vinyl alcohol) (PVA)), proteins (bovine serum albumin (BSA), ovalbumin, gelatin, and ossein), and smaller organics such as lecithin (1-stearoyl-2-oleoyl phosphatidylcholine, SOPC) and Aethonium (1,2-ethylene-bis(N-dimethyl carbodecyl oxymethyl) ammonium dichloride) with nanosilicas A-300 (S(BET)=232 and 297 m(2) g(-1)) and A-50 (S(BET)=52 m(2)g(-1)) was studied using dynamic light scattering, adsorption, and infrared (FTIR) spectroscopy methods. Time-dependent rearrangement of particle size distributions (PSDs) depicts appearance of both smaller and larger aggregates for silica/PEG(I-first adsorbate)/BSA(II-second adsorbate) and silica/PVP(I)/BSA(II) (i.e., BSA adsorbs onto PEG/silica or PVP/silica) than that for silica/organic compound I. However, in the cases of PVA(I)-BSA(II) and PVA(I)-SOPC(II) a similar effect is not observed because only increased aggregation occurs. The successive equilibrium adsorption of similar pairs shows a diminution of the adsorption of the second compound (gelatin, ovalbumin) with increasing amount of the first adsorbed polymer (PEG or PVP). PMID:16643935

  1. Antimicrobial Efficacy of Zinc Oxide Quantum Dots Against Listeria Monocytogenes, Salmonella Enteritidis and Escherichia coli O157:H7

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Zinc oxide quantum dots (ZnO QDs) in a powder form, a ZnO-polystyrene (PS) film form and a polyvinylprolidone capped ZnO (ZnO-PVP) gel form were prepared and their antibacterial activities against foodborne pathogenic Listeria monocytogenes, Salmonella Enteritidis and Escherichia coli O157:H7 in cul...

  2. Genetic Diversity and Agronomic Improvement of North American Soybean Germplasm

    Technology Transfer Automated Retrieval System (TEKTRAN)

    From 1970 to 2008 there were 2,242 soybean cultivars registered in North America through U.S. PVP, U.S. utility patent, and journal registration. Of these, 80% were developed through proprietary and 20% through public programs. The most frequently used germplasm for cultivar development were the cul...

  3. Pallidotomy revisited. Analysis of posteroventral pallidotomy.

    PubMed

    Narabayashi, H

    1997-01-01

    Posteroventral pallidotomy (PVP) has been shown to alleviate motor symptoms in Parkinson's disease (PD), e.g., rigidity, secondary akinesia due to existence of muscle rigidity and slight tremor, but not the marked tremor. For the latter, additional lesion of the ventral intermediate nucleus of the thalamus is necessary. Akinesia was divided into three subtypes, and the influence of PVP on each type is described. Primary akinesia is not changed by either PVP or thalamotomy but responds well to L-dopa. Psychological symptoms, i.e., depressive mood, loss of initiation or abulia, and lowered emotional activity, which are generally termed as bradyphrenia, benefit well from PVP but less from thalamotomy. This effect is interpreted as due to the lesion extending into the ventral pallidum, where a small posterior part of the limbic-motor projections may possibly be involved. Such experience suggests that the third type of akinesia in PD, named the 'psychomotor or limbic-motor type' by the author, can be improved by the surgical procedure on the ventral globus pallidus. These observations offer an important chance to understand the psychological symptoms in PD as a result of dopamine deficiency of ventral tegmental area neurons projecting to the ventral striatum, which further influences the ventral pallidum. PMID:9711734

  4. Radiation synthesis of superabsorbent CMC based hydrogels for agriculture applications

    NASA Astrophysics Data System (ADS)

    Raafat, Amany I.; Eid, Mona; El-Arnaouty, Magda B.

    2012-07-01

    A series of superabsorbent hydrogel based on carboxymethylcellulose (CMC) and polyvinylpyrrolidone (PVP) crosslinked with gamma irradiation have been proposed for agriculture application. The effect of preparation conditions such as feed solution composition and absorbed irradiation dose on the gelation and swelling degree was evaluated. The structure and the morphology of the superabsorbent CMC/PVP hydrogel were characterized using Fourier transform infrared spectroscopy technique (FTIR), and scanning electron microscope (SEM). Effect of ionic strength and cationic and anionic kinds on the swelling behavior of the obtained hydrogel was investigated. Urea as an agrochemical model was loaded onto the obtained hydrogel to provide nitrogen (N) nutrients. The water retention capability and the urea release behavior of the CMC/PVP hydrogels were investigated. It was found that, the obtained CMC/PVP hydrogels have good swelling degree that greatly affected by its composition and absorbed dose. The swelling was also extremely sensitive to the ionic strength and cationic kind. Owing to its considerable slow urea release, good water retention capacity, being economical, and environment-friendly, it might be useful for its application in agriculture field.

  5. Fabrication of Polyvinylpyrrolidone Micro-/Nanostructures Utilizing Microcontact Printing

    ERIC Educational Resources Information Center

    Sanders, Wesley C.

    2015-01-01

    This paper describes a laboratory exercise that provides students enrolled in introductory nanotechnology courses with an opportunity to synthesize polymer structures with micro- and nanoscale dimensions. Polyvinylpyrrolidone (PVP) films deposited on corrugated PDMS stamps using student-built spin coaters were transferred to clean, dry substrates…

  6. Investigating the Influence of Polymers on Supersaturated Flufenamic Acid Cocrystal Solutions.

    PubMed

    Guo, Minshan; Wang, Ke; Hamill, Noel; Lorimer, Keith; Li, Mingzhong

    2016-09-01

    The development of enabling formulations is a key stage when demonstrating the effectiveness of pharmaceutical cocrystals to maximize the oral bioavailability for poorly water soluble drugs. Inhibition of drug crystallization from a supersaturated cocrystal solution through a fundamental understanding of the nucleation and crystal growth is important. In this study, the influence of the three polymers of polyethylene glycol (PEG), polyvinylpyrrolidone (PVP), and a copolymer of N-vinly-2-pyrrodidone (60%) and vinyl acetate (40%) (PVP-VA) on the flufenamic acid (FFA) crystallization from three different supersaturated solutions of the pure FFA and two cocrystals of FFA-NIC CO and FFA-TP CO has been investigated by measuring nucleation induction times and desupersaturation rates in the presence and absence of seed crystals. It was found that the competition of intermolecular hydrogen bonding among drug/coformer, drug/polymer, and coformer/polymer was a key factor responsible for maintaining supersaturation through nucleation inhibition and crystal growth modification in a cocrystal solution. The supersaturated cocrystal solutions with predissolved PEG demonstrated more effective stabilization in comparison to the pure FFA in the presence of the same polymer. In contrast, neither of the two cocrystal solutions, in the presence of PVP or PVP-VA, exhibited a better performance than the pure FFA with the same predissolved polymer. The study suggests that the selection of a polymeric excipient in a cocrystal formulation should not be solely dependent on the interplay of the parent drug and polymer without considering the coformer effects. PMID:27494289

  7. The Influence of Drug Physical State on the Dissolution Enhancement of Solid Dispersions Prepared Via Hot-Melt Extrusion: A Case Study Using Olanzapine

    PubMed Central

    Pina, Maria Fátima; Zhao, Min; Pinto, João F; Sousa, João J; Craig, Duncan Q M

    2014-01-01

    In this study, we examine the relationship between the physical structure and dissolution behavior of olanzapine (OLZ) prepared via hot-melt extrusion in three polymers [polyvinylpyrrolidone (PVP) K30, polyvinylpyrrolidone-co-vinyl acetate (PVPVA) 6:4, and Soluplus® (SLP)]. In particular, we examine whether full amorphicity is necessary to achieve a favorable dissolution profile. Drug–polymer miscibility was estimated using melting point depression and Hansen solubility parameters. Solid dispersions were characterized using differential scanning calorimetry, X-ray powder diffraction, and scanning electron microscopy. All the polymers were found to be miscible with OLZ in a decreasing order of PVP>PVPVA>SLP. At a lower extrusion temperature (160°C), PVP generated fully amorphous dispersions with OLZ, whereas the formulations with PVPVA and SLP contained 14%–16% crystalline OLZ. Increasing the extrusion temperature to 180°C allowed the preparation of fully amorphous systems with PVPVA and SLP. Despite these differences, the dissolution rates of these preparations were comparable, with PVP showing a lower release rate despite being fully amorphous. These findings suggested that, at least in the particular case of OLZ, the absence of crystalline material may not be critical to the dissolution performance. We suggest alternative key factors determining dissolution, particularly the dissolution behavior of the polymers themselves. PMID:24765654

  8. The influence of drug physical state on the dissolution enhancement of solid dispersions prepared via hot-melt extrusion: a case study using olanzapine.

    PubMed

    Pina, Maria Fátima; Zhao, Min; Pinto, João F; Sousa, João J; Craig, Duncan Q M

    2014-04-01

    In this study, we examine the relationship between the physical structure and dissolution behavior of olanzapine (OLZ) prepared via hot-melt extrusion in three polymers [polyvinylpyrrolidone (PVP) K30, polyvinylpyrrolidone-co-vinyl acetate (PVPVA) 6:4, and Soluplus® (SLP)]. In particular, we examine whether full amorphicity is necessary to achieve a favorable dissolution profile. Drug–polymer miscibility was estimated using melting point depression and Hansen solubility parameters. Solid dispersions were characterized using differential scanning calorimetry, X-ray powder diffraction, and scanning electron microscopy. All the polymers were found to be miscible with OLZ in a decreasing order of PVP>PVPVA>SLP. At a lower extrusion temperature (160°C), PVP generated fully amorphous dispersions with OLZ, whereas the formulations with PVPVA and SLP contained 14%-16% crystalline OLZ. Increasing the extrusion temperature to 180°C allowed the preparation of fully amorphous systems with PVPVA and SLP. Despite these differences, the dissolution rates of these preparations were comparable, with PVP showing a lower release rate despite being fully amorphous. These findings suggested that, at least in the particular case of OLZ, the absence of crystalline material may not be critical to the dissolution performance. We suggest alternative key factors determining dissolution, particularly the dissolution behavior of the polymers themselves. PMID:24765654

  9. Nickel nanoparticles with hcp structure: Preparation, deposition as thin films and application as electrochemical sensor.

    PubMed

    Neiva, Eduardo G C; Oliveira, Marcela M; Marcolino, Luiz H; Zarbin, Aldo J G

    2016-04-15

    Hexagonal close packed (hcp) nickel nanoparticles stabilized by polyvinylpyrrolidone (PVP) were synthesized through the thermal treatment of face centered cubic (fcc) nickel nanoparticles. Controlling both the temperature of the heat treatment and the amount of PVP was possible the control of the hcp/fcc rate in the samples, where the higher Ni/PVP ratio produces only the hcp-nickel phase (average size of 8.9 nm) highly stable in air. The crystalline structure, the presence of PVP, the size of the nanoparticles and the stability of the hcp-nickel were confirmed using X-ray diffractometry, Fourier transform infrared spectroscopy, transmission electron microscopy, Raman spectroscopy, scanning electron microscopy and thermogravimetric analysis. Thin films of hcp and fcc nickel nanoparticles were prepared through a biphasic system and deposited over indium-doped tin oxide (ITO) substrates, which were electrochemically characterized and applied as glycerol amperometric sensors in NaOH medium. Parameters as the number of cycles applied and the scan rate were evaluated and indicate that hcp nickel nanoparticles are more reactive to form Ni(OH)2 and lead to more electroactive Ni(OH)2 structure. The hcp nickel nanoparticles-modified electrode showed the best sensitivity (0.258 μA L μmol(-1)) and detection limit (2.4 μmol L(-1)) toward glycerol. PMID:26821149

  10. Radiation stability of resveratrol in immobilization on poly vinyl pyrrolidone hydrogel dressing for dermatological use

    NASA Astrophysics Data System (ADS)

    Momesso, Roberta G. R. A. P.; Moreno, Carolina S.; Rogero, Sizue O.; Rogero, José R.; Spencer, Patrick J.; Lugão, Ademar B.

    2010-03-01

    The polyphenol trans-resveratrol is a natural phytoalexin, which is found in red wine and in a wide variety of plant species. Resveratrol displays a wide array of biological activities, such as modulation of lipid metabolism, anti-inflammatory and antioxidant activities. This active compound immobilized in polyvinylpyrrolidone (PVP) hydrogel could be very interesting for topical administration, as a dressing form for dermatological use. However, PVP hydrogel obtained by radiation-induced crosslinking can cause undesirable hydrolysis reactions in the active compound. The aim of this work was to verify the resveratrol stability after irradiation at 0.5 and 1 kGy in the presence of ethanol, methanol or tert-butyl alcohol. The integrity of these samples was compared to unirradiated resveratrol by HPLC. The PVP hydrogel matrix was characterized by gel fraction, swelling and in vitro biocompatibility test. The results of gel fraction and swelling degree were approximately 90% and 1600%, respectively. The cytotoxicity assay showed absence of toxicity for this formulation after crosslinking and sterilization, indicating that the PVP hydrogel formulation was appropriate for resveratrol immobilization to produce a dressing for dermatological use.

  11. Development of curcumin nanocrystal: physical aspects.

    PubMed

    Rachmawati, Heni; Al Shaal, Loaye; Müller, Rainer H; Keck, Cornelia M

    2013-01-01

    Curcumin, a naturally occuring polyphenolic phytoconstituent, is isolated from the rhizomes of Curcuma longa Linn. (Zingiberaceae). It is water insoluble under acidic or neutral conditions but dissolves in alkaline environment. In neutral or alkaline conditions, curcumin is highly unstable undergoing rapid hydrolytic degradation to feruloyl methane and ferulic acid. Thus, the use of curcumin is limited by its poor aqueous solubility in acidic or neutral conditions and instability in alkaline pH. In the present study, curcumin nanocrystals were prepared using high-pressure homogenization, to improve its solubility. Five different stabilizers [polyvinyl alcohol (PVA), polyvinyl pyrrolidone (PVP), d-α-tocopherol polyethylene glycol 1000 succinate (TPGS), sodium dodecyl sulfate (SDS), carboxymethylcellulose sodium salt] possessing different stabilization mechanism were investigated. The nanoparticles were characterized with regard to size, surface charge, shape and morphology, thermal property, and crystallinity. A short-term stability study was performed storing the differently stabilized nanoparticles at 4°C and room temperature. PVA, PVP, TPGS, and SDS successfully produced curcumin nanoparticle with the particle size in the range of 500-700 nm. PVA, PVP, and TPGS showed similar performance in preserving the curcumin nanosuspension stability. However, PVP is the most efficient polymer to stabilize curcumin nanoparticle. This study illustrates that the developed curcumin nanoparticle held great potential as a possible approach to improve the curcumin solubility then enhancing bioavailability. PMID:23047816

  12. Sugar-polymer hydrogen bond interactions in lyophilized amorphous mixtures.

    PubMed

    Taylor, L S; Zografi, G

    1998-12-01

    The objective of this work was to investigate hydrogen bonding interactions between a variety of glass-forming sugars and a model polymer, poly(vinylpyrrolidone) (PVP), in binary amorphous solid solutions, produced by lyophilization. The glass transition temperatures of the sugars and sugar-PVP colyophilized mixtures were assessed using differential scanning calorimetry. The hydrogen bonding interactions between each sugar and PVP were monitored using FT-Raman spectroscopy. Sucrose was found to hydrogen bond to a greater extent with PVP at a particular sugar:polymer ratio than the other disaccharides studied including trehalose and the trisaccharide raffinose. Maltodextrins showed a decreased tendency to hydrogen bond with the polymer compared to the lower molecular weight sugars. The extent of hydrogen bonding was found to correlate inversely with the glass transition temperature of the sugar, with the tendency to hydrogen bond decreasing as the Tg increased. The importance of hydrogen bonding interactions to the thermodynamics of mixing in amorphous solids is discussed. PMID:10189276

  13. Robust Ag nanoplate ink for flexible electronics packaging

    NASA Astrophysics Data System (ADS)

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

    2015-04-01

    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 (<250 °C) was primarily due to adhesive bonding. It is found that, utilizing photonic sintering, ~70 °C reduction of transformation temperature from adhesive to metallic bonding was achieved compared to that of thermal sintering. A numerical simulation was developed to better understand the influences of the light-induced heat generation, which demonstrated near-infrared light can facilitate sintering. Bonding strengths of 27 MPa were achieved at room temperatures, and 29.4 MPa at 210 °C with photonic sintering. Moreover, the anisotropic resistivity was observed with different thermal dependences. These results demonstrate Ag nanoplate inks have potential for low temperature 3D interconnections in lead-free microcircuits, flexible electronic packaging, and diverse sensing applications.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 (<250 °C) was primarily due to adhesive bonding. It is found that, utilizing photonic sintering, ~70 °C reduction of transformation temperature from adhesive to

  14. Povidone-iodine liposomes--an overview.

    PubMed

    Reimer, K; Fleischer, W; Brögmann, B; Schreier, H; Burkhard, P; Lanzendörfer, A; Gümbel, H; Hoekstra, H; Behrens-Baumann, W

    1997-01-01

    In recent years, liposomes have been increasingly explored as novel drug delivery systems, and several liposome-based drug products have been approved in Europe, the USA and Japan. Depending on size, composition and surface characteristics, liposomes interact specifically with biological structures. Liposomal drug products provide a topical activity at the desired locus of action and are deemed more effective and less toxic than conventional drug formulations. The combination of povidone-iodine (PVP-I) and liposomes unites the exceptional microbicidal activity of the antiseptic substance with the excellent tolerability and lack of immunogenicity of liposomes; in addition, liposomes provide a moist molecular film for the wound environment. The multilamellar vesicles act as microreservoirs hence prolonging the release of the active ingredient. Although no commercial product for repeated application on the eye is currently available, PVP-I has been used in ophthalmology not only for pre- and postoperative antisepsis, but also for the treatment of bacterial and viral conjunctivitis and for prophylaxis against ophthalmia neonatorum. For these indications, liposomal formulations with 2.5 and 5.0% PVP-I were developed. These eye drops are isotonic with tear fluid at pH 6. First in vitro tests demonstrated an excellent antimicrobial efficacy, and a placebo-controlled clinical study on volunteers showed a very good local tolerability. A study on rabbits demonstrated positive results of the PVP-I liposome eye drops compared to placebo and the broadspectrum antibiotic Polyspectran in a standardized model of Staphylococcus aureus deep eye infection. The other aim is a well-tolerated liposomal PVP-I hydrogel for improved antiseptic wound treatment with moisturizer. It has been reported that liposomes are enriched at the wound bottom for direct action against infection and support of wound healing. An animal study on the efficacy and tolerability of different formulations of a

  15. Effect of Rehydration Fluid Osmolality on Plasma Volume and Vasopressin in Resting Dehydrated Men

    NASA Technical Reports Server (NTRS)

    Geelen, Ghislaine; Greenleaf, J. E.; Keil, L. C.; Wade, Charles E. (Technical Monitor)

    1994-01-01

    Elevated plasma vasopressin concentration [PVP], which may act as a dipsogen, decreases promptly following the ingestion of fluids in many mammals including humans. The purpose for this study was to determine whether fluids of varied electrolyte and carbohydrate composition and osmolality (Osm] would modify post-drinking decreases in [PVP] which could be attributed to interaction with plasma volume (PV)- or fluid-electrolyte interactive hormones. Five men (23-41 yr, 78.0 +/- SD 8.2 kg), water deprived for 24 h, drank six fluids (12 ml/kg, at 16.5C in 4.0-6.2 min): water (30 m0sm/kg), NaCl (70 mOsm/kg), NaCl + NaCitrate (270 mOsm/kg), NaCl + 9.7% glucose (650 mOsm/kg), and two commercial drinks containing various ionic and carbohydrate contents (380 and 390 mOsm/kg). Blood (20 ml/sample) was drawn at -5 min before and at +3, +9, +15, +30, and +70 min after drinking. Heart rate, blood pressures, and plasma renin activity, {Na+], [K+], [Osm], aldosterone, atrial natriuretic peptide, and epinephrine concentrations were unchanged after drinking. Post-drinking [PVP] decreased from 1.7 - 3.7 pg/ml within 3 min with all fluids independently of their composition, [Osm], or delta PV; with maximal depression to 0.1-0.7 pg/ml (p<0.05) by 15 min. The continued [PVP] depression with all fluids from 15 to 70 min was accompanied by unchanged plasma (Osm] but 1.8-7.6% increases (p<0.05) in PV with 3) fluids (2 commercial and NaCitrate) and no change with the others. Percent changes in mean [PVP] and plasma norepinephrine concentrations [PNE] at 15 min correlated -0.70 (P<0.10) suggesting that about half the variability in [PVP I I depression was associated with [PNE]. Thus, part of the mechanism for post-drinking [PVP] depression may involve a drinking stimulated norepinephrine (neural) factor.

  16. Synthesis and characterization of nano-manganese dioxide and titanium dioxide

    NASA Astrophysics Data System (ADS)

    Peddi, Sasya

    Nano sized manganese dioxide was synthesized using hydrothermal and co-precipitation methods by the reduction of hydrogen peroxide and potassium permanganate in respective methods. The co-precipitation method of synthesis was expanded to synthesize nano sized Titanium Dioxide. Characterization of the synthesized material was carried out by Elemental Analysis, X-Ray Diffraction (XRD), Thermal Gravimetric Analysis (TGA), Differential Thermal Analysis (DTA), Infra Red Spectroscopy (FTIR) and Scanning Electron Microscopy (SEM). SEM analysis showed that the MnO2 prepared by hydrothermal method is made of spherical nanoparticles with sizes ranging from 15 nm--30 nm and the MnO2 prepared by co-precipitation method showed nanospheres of 20 nm--100 nm with several nano disks incorporated in these sphere of about 5 nm--50 nm in diameter. X-ray revealed that the MnO2 prepared by hydrothermal shows two different transitions from amorphous MnO2 to crystalline Mn2O3 and Mn2O3- Mn2O 3 Bixbyte with substantial amount of unreacted PVP in it, which is lost when heated to higher temperatures which are supported by data from DTA and TGA. In co-precipitation only one transition is observed that is from amorphous MnO2 to crystalline Mn2O3 Bixbyte and traces of unreacted PVP. Titanium Dioxide synthesized using PVP led to uniform spherical nano particles of 20 nm--100 nm with some unreacted PVP. X-Ray analysis shows one transition from amorphous TiO2 to crystalline TiO 2 Anatase. The TiO2 prepared without PVP is poorly crystalline to X-rays and identified as Brookite when heated to higher temperature. The SEM micrographs of TiO2 without PVP did not show any uniformity in particle size and shape distribution and lost homogeneity. The results from our study suggest that the clean, uniform and homogeneous nanoparticles can be prepared using a simple, room temperature, non-expensive co-precipitation method using PVP.

  17. Formation of core-shell-structured Zn2SnO4-carbon microspheres with superior electrochemical properties by one-pot spray pyrolysis

    NASA Astrophysics Data System (ADS)

    Hong, Young Jun; Kang, Yun Chan

    2014-12-01

    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 2nd and 120th 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 2nd and 120th 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.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 2nd and 120th 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 2nd and

  18. Comparative Behavioral Pharmacology of Three Pyrrolidine-Containing Synthetic Cathinone Derivatives

    PubMed Central

    Dolan, Sean B.; Forster, Michael J.

    2015-01-01

    Synthetic cathinones, often sold as “bath salts,” are a popular class of recreational drugs used as quasi-legal alternatives to cocaine, methamphetamine, and methylenedioxymethamphetamine. The increased prevalence and health consequences of synthetic cathinone use has prompted regulatory agencies to control a number of these compounds; however, a broad class of analogous compounds known as the second-generation cathinones has been brought to the market to take the place of the banned synthetic cathinone derivatives. The current study aims to characterize the behavioral pharmacology of three pyrrolidinylated second-generation cathinones: 4-methyl-α-pyrrolidinopropiophenone (4ʹ-MePPP), α-pyrrolidinopropiobutiophenone (α-PBP), and α-pyrrolidinopentiophenone (α-PVP). Locomotor activity was tested in mice over an 8-hour period. The discriminative stimulus effects of these compounds were tested in rats trained to discriminate either cocaine or methamphetamine. The rewarding effects of these drugs were assessed in mice using conditioned place preference. Both α-PBP and α-PVP produced long-lasting increases in locomotor activity across a wide range of doses, whereas 4ʹ-MePPP produced locomotor stimulation only at 30 mg/kg. Both α-PBP and α-PVP fully substituted for the discriminative stimulus effects of both cocaine and methamphetamine, whereas 4ʹ-MePPP substituted fully for the discriminative stimulus effects of methamphetamine only. Both α-PBP and α-PVP produced conditioned place preference in an inverted U-shaped dose effect, whereas 4ʹ-MePPP did not produce conditioned place preference. These findings suggest that α-PBP and α-PVP are likely to be recreationally used and have potential for addiction and abuse, but 4ʹ-MePPP may not. PMID:25998047

  19. Stretch and radial compression studies on relaxed skinned muscle fibers of the frog.

    PubMed Central

    Maughan, D W; Godt, R E

    1979-01-01

    The influence of stretch and radial compression on the width of mechanically skinned fibers from the semitendinosus muscle of the frog (R. pipiens) was examined in relaxing solutions with high-power light microscopy. Fibers were skinned under mineral oil. We find that, after correcting for water uptake in the oil, fiber width increased by an average of 28% upon transfer from oil to relaxing medium, with some tendency for greater swelling at longer sarcomere lengths. Subsequently, fibers were compressed by addition of the long-chain polymer polyvinylpyrrolidone (PVP-40, number average molecular weight 40,000) to relaxing solutions. Sarcomere length does not appear to be affected by addition of PVP. At any PVP concentration, the inverse square of the fiber width increased smoothly and linearly with increasing stretch for sarcomere lengths between 2.10 and 4.60 micrometer. At any fixed sarcomere length, fiber width decreased linearly with the logarithm of the osmotic compressive pressure exerted by PVP (2-10% concentration). From this logarithmic relation we estimate that the swelling pressure of the intact fiber is 3.40 x 10(3) N/m2, between that of a 2 and a 3% PVP solution. The pressure giving rise to fiber swelling is not due to dilation of the sarcoplasmic reticulum (SR), since the experimental results above were not significantly different after treatment with 0.5% BRIJ-58, a nonionic detergent that disrupts the SR. Swelling may be due simply to elastic structures within the fiber that are constrained in the intact cell. Values of bulk moduli of fibers, calculated from the compression experiments, and preliminary measurements of Young's modulus from stretch experiments, are quantitatively consistent with the idea that skinned fibers behave as nonisotropic elastic bodies. Images FIGURE 1 PMID:318072

  20. The Effectiveness of Gelfoam Technique before Percutaneous Vertebroplasy: Is It Helpful for Prevention of Cement Leakage? A Prospective Randomized Control Study

    PubMed Central

    Oh, Jae-Sang; Shim, Jai-Joon; Lee, Kyeong-Seok; Yoon, Seok-Mann; Bae, Hack-Gun

    2016-01-01

    Objective Preinjection gelfoam embolization during percutaneous vertebroplasty (PVP) has been thought alternative technique to prevent the leakage of bone cement. The goal of this study was to evaluate whether the gelfoam techniques are useful to reduce bone cement leakage. Methods Total 100 PVPs of osteoporotic spine compression fractures were performed by 1 spine surgeon who experienced more than 500 PVP cases under prospective control study. Operation was done in T-L junction (T10-L2) fractures with bi-transpedicular approach. Preinjection gelfoam PVP was done in the 50 levels. As control group, PVP without gelfoam was done in the 50 levels. We did not perform preoperative venography. We inserted normal saline-mixed gelfoam to the anterior third of vertebral body via PVP needle, and then 3mL of polymethylmetacrylate (PMMA) was injected. We prospectively evaluated the incidence and leakage pattern of PMMA by postoperative computed tomography. Results Between gelfoam and control groups, there were 11 leaks (22%) versus 12 leaks (26%). The mean operation time was 7.00 minutes versus 6.30 minutes. In gelfoam group, there were 6 spinal canal leaks, 4 paravertebral venous leaks, and 1 soft tissue leaks. In control group, there were 4 spinal canal leaks, 8 paravertebral venous leaks, and 1 disc space leak. In spite of cement leakage, there was no symptomatic case in both groups. Statistically, gelfoam technique was not related to decrease the incidence of leakage (p=0.64). Conclusion Our prospective study showed that it did not significantly decrease cement leakage when vertebroplasty is performed by experienced spine surgeon. PMID:27437015

  1. Anti-inflammatory properties of a liposomal hydrogel with povidone-iodine (Repithel) for wound healing in vitro.

    PubMed

    Beukelman, C J; van den Berg, A J J; Hoekstra, M J; Uhl, R; Reimer, K; Mueller, S

    2008-09-01

    A liposomal hydrogel with 3% povidone-iodine (PVP-ILH, Repithel) has shown clinical benefit in settings where inflammation and/or reactive oxygen species are thought to impede wound healing (e.g., burns, chronic wounds and in smokers). This in vitro study investigated whether PVP-ILH is able to reduce inflammatory events responsible for the impairment of the wound healing process in such patients. Therefore, the following assays were conducted with PVP-ILH (and derived control hydrogels to identify the component responsible for the effect): inhibition of reactive oxygen species production by human polymorphonuclear neutrophils (PMNs) and in a cell-free system, oxygen consumption assay of PMNs (prior to oxidative burst), inhibition of human complement (limiting the generation of complement factors), mast cell degranulation, nitric oxide production by murine macrophages and TNF-alpha production by human monocytes/macrophages. Where toxicity could cause cell inhibition, cell viability was assessed. PVP-ILH and its components interacted in our series of bioassays at various stages in the inflammation cascade. Scavenging of superoxide anions was the most pronounced effect. Furthermore, povidone-iodine inhibited PMN production of reactive oxygen species (inhibition of oxygen consumption) and a mast cell inhibitory (stabilising) activity was observed. Based on these results, the clinically observed, beneficial wound healing effects of PVP-ILH may also be attributed to an impediment of inflammatory activity, mainly by iodine's free radical scavenging. Controlling oxidative stress in the wound may be of great importance, especially since further reactions as, e.g., the formation of peroxynitrite from NO and ROS are prevented. PMID:18378399

  2. Strain Hardening and Strain Softening of Reversibly Cross-linked Supramolecular Polymer Networks

    PubMed Central

    Xu, Donghua; Craig, Stephen L.

    2011-01-01

    The large amplitude oscillatory shear behavior of metallo-supramolecular polymer networks formed by adding bis-Pd(II) cross-linkers to poly(4-vinylpyridine) (PVP) in dimethyl sulfoxide (DMSO) solution is reported. The influence of scanning frequency, dissociation rate of cross-linkers, concentration of cross-linkers, and concentration of PVP solution on the large amplitude oscillatory shear behavior is explored. In semidilute unentangled PVP solutions, above a critical scanning frequency, strain hardening of both storage moduli and loss moduli is observed. In the semidilute entangled regime of PVP solution, however, strain softening is observed for samples with faster cross-linkers (kd ∼ 1450 s−1), whereas strain hardening is observed for samples with slower cross-linkers (kd ∼ 17 s−1). The mechanism of strain hardening is attributed primarily to a strain-induced increase in the number of elastically active chains, with possible contributions from non-Gaussian stretching of polymer chains at strains approaching network fracture. The divergent strain softening of samples with faster cross-linkers in semidilute entangled PVP solutions, relative to the strain hardening of samples with slower cross-linkers, is consistent with observed shear thinning/shear thickening behavior reported previously and is attributed to the fact that the average time that a cross-linker remains detached is too short to permit the local relaxation of polymer chain segments that is necessary for a net conversion of elastically inactive to elastically active cross-linkers. These and other observations paint a picture in which strain softening and shear thinning arise from the same set of molecular mechanisms, conceptually uniting the two nonlinear responses for this system. PMID:22043083

  3. COMPETING PROPERTIES OF MUCOADHESIVE FILMS DESIGNED FOR LOCALIZED DELIVERY OF IMIQUIMOD

    PubMed Central

    Ramineni, Sandeep K; Cunningham, Larry L; Dziubla, Thomas D; Puleo, David A

    2013-01-01

    Oral mucosal delivery has gained prominence in the last two decades because the rich vasculature of the tissue enables rapid delivery and avoidance of first pass metabolism. Although commercial mucoadhesives are used for systemic delivery, systems are not currently available for treatment of local conditions. In the present work, mucoadhesive films are being developed for locally controlled release of an immune response modifier for preventing precancerous lesions from progressing to oral squamous cell carcinoma. Previous research showed that films composed of polyvinylpyrrolidone (PVP) and carboxymethylcellulose (CMC) released imiquimod in a sustained manner for 3 hr. In continuing development of the system, additional key properties were investigated with changes in composition. While adhesive properties in pull-off (0.42±0.03 to 1.1±0.1 N/cm2) and shear adhesion (1.7±0.25 to 5.6±1.4 N/cm2) increased with increasing PVP content of films, tensile properties, such as modulus (6.9±1.5 to 1.8±0.2 MPa) and ultimate strength (4.2±0.7 to 2.1±0.02 MPa), decreased as PVP content increased. Release profiles of the films showed that an increased PVP content resulted in burst release and faster erosion compared to sustained release and slower erosion with more CMC. Studies of transport kinetics showed that the films doubled the amount of imiquimod localized within epithelium compared to drug in solution, increasing their potential for local treatment of oral dysplasia. The mucoadhesive drug delivery system based on CMC and PVP offers a wide range of these properties without addition of new constituents. PMID:23750320

  4. Antiproliferative/cytotoxic effects of molecular iodine, povidone-iodine and Lugol's solution in different human carcinoma cell lines

    PubMed Central

    Rösner, Harald; Möller, Wolfgang; Groebner, Sabine; Torremante, Pompilio

    2016-01-01

    Clinical trials have revealed that molecular iodine (I2) has beneficial effects in fibrocystic breast disease and in cyclic mastalgia. Likewise, povidone-iodine (PVP-I), which is widely used in clinical practice as an antiseptic agent following tumour surgery, has been demonstrated to have cytotoxic effects on colon cancer and ascites tumour cells. Our previous study indicated that the growth of breast cancer and seven other human malignant cell lines was variably diminished by I2 and iodolactones. With the intention of developing an iodine-based anticancer therapy, the present investigations extended these studies by comparing the cytotoxic capacities of I2, potassium iodide (KJ), PVP-I and Lugol's solution on various human carcinoma cell lines. Upon staining the cell nuclei with Hoechst 33342, the cell densities were determined microscopically. While KJ alone did not affect cell proliferation, it enhanced the antiproliferative activity of I2. In addition, PVP-I significantly inhibited the proliferation of human MCF-7 breast carcinoma, IPC melanoma, and A549 and H1299 lung carcinoma cells in a concentration corresponding to 20 µM I2. Likewise, Lugol's solution in concentrations corresponding to 20–80 µM I2 were observed to reduce the growth of MCF-7 cells. Experiments with fresh human blood samples revealed that the antiproliferative activity of PVP-I and I2 is preserved in blood plasma to a high degree. These findings suggest that PVP-I, Lugol's solution, and a combination of iodide and I2 may be potent agents for use in the development of antitumour strategies. PMID:27602156

  5. Asymmetric flow field-flow fractionation of manufactured silver nanoparticles spiked into soil solution.

    PubMed

    Koopmans, G F; Hiemstra, T; Regelink, I C; Molleman, B; Comans, R N J

    2015-05-01

    Manufactured metallic silver nanoparticles (AgNP) are intensively utilized in consumer products and this will inevitably lead to their release to soils. To assess the environmental risks of AgNP in soils, quantification of both their concentration and size in soil solution is essential. We developed a methodology consisting of asymmetric flow field-flow fractionation (AF4) in combination with on-line detection by UV-vis spectroscopy and off-line HR-ICP-MS measurements to quantify the concentration and size of AgNP, coated with either citrate or polyvinylpyrrolidone (PVP), in water extracts of three different soils. The type of mobile phase was a critical factor in the fractionation of AgNP by AF4. In synthetic systems, fractionation of a series of virgin citrate- and PVP-coated AgNP (10-90 nm) with reasonably high recoveries could only be achieved with ultrahigh purity water as a mobile phase. For the soil water extracts, 0.01% (w:v) sodium dodecyl sulfate (SDS) at pH 8 was the key to a successful fractionation of the AgNP. With SDS, the primary size of AgNP in all soil water extracts could be determined by AF4, except for PVP-coated AgNP when clay colloids were present. The PVP-coated AgNP interacted with colloidal clay minerals, leading to an overestimation of their primary size. Similar interactions between PVP-coated AgNP and clay colloids can take place in the environment and facilitate their transport in soils, aquifers, and surface waters. In conclusion, AF4 in combination with UV-vis spectroscopy and HR-ICP-MS measurements is a powerful tool to characterize AgNP in soil solution if the appropriate mobile phase is used. PMID:25798868

  6. Dissolution and mechanical behaviors of recrystallized carbamazepine from alcohol solution in the presence of additives

    NASA Astrophysics Data System (ADS)

    Nokhodchi, A.; Bolourtchian, N.; Dinarvand, R.

    2005-02-01

    Carbamazepine (CBZ) crystals were grown from pure ethanol solutions containing various additives (PEG 4000, PVP K30 or Tween 80). Physical characteristics of the crystals were studied for the morphology of crystals using scanning electron microscope, for the identification of polymorphism by X-ray powder diffraction (XRPD) and FT-IR, and for thermodynamic properties using differential scanning calorimetery (DSC). The dissolution behaviour of various carbamazepine crystals was also studied by dissolution apparatus II at pH 7.4 containing 1% sodium lauryl sulphate (SLS). The scanning electron micrograph (SEM) studies showed that the presence of the additives in the solutions growth medium affected the morphology and size of carbamazepine crystals. SEMs of untreated and treated carbamazepine crystals obtained from alcohol containing PEG 4000, PVP K30 or Tween 80 showed that the crystal shape of untreated carbamazepine is flaky or thin plate-like, whereas the crystals obtained from alcohol containing no additive, PEG 4000, PVP K30 or Tween 80 are polyhedral prismatic, block-shaped, polyhedral or hexagonal, respectively. XRPD, FT-IR and DSC results showed that the untreated CBZ was form III and recrystallization of CBZ in the absence or presence of the additives did not cause any polymorphic changes. The results showed that the higher dissolution rate and compact strength were observed for the crystals obtained in the presence of PVP K30. The presence of the additives in crystallization medium alters crystal morphology of carbamazepine, but only the samples crystallized in the presence of PVP K30 showed an improvement in dissolution rate and tensile strength.

  7. Preparation, Characterization and in vivo Evaluation of Simple Monolithic Ethylcellulose-coated Pellets Containing Topiramate with Biphasic Release Characteristics.

    PubMed

    Gong, Wei; Wang, Yuli; Shao, Shuai; Xie, Si; Shan, Li; Yang, Meiyan; Gao, Chunsheng; Zhong, Wu

    2016-01-01

    In our previous study, polyvinylpyrrolidone (PVP) was used both as a binder and a pore-former to prepare ethylcellulose (EC)-coated pellets to deliver topiramate (TPM) for a controlled release profile. The objective of this work was to further optimize the formulation and evaluate the in vivo profiles of TPM sustained-release pellets. Similar to the previous formulation with no binder, the in vitro drug release of TPM sustained-release pellets with 50% PVP binder in drug layer was sensitive to pore-former PVP level ranged from 27.0% to 29.0%. The higher the level of PVP was, the quicker release rate in vitro was. Moreover, when the proportion of poreformer PVP decreased, the Cmax decreased, and the tmax and mean residence time of TPM coated pellets were both prolonged. The in vitro release profile of optimal formulation showed biphasic release characteristics similar to reference formulation Trokendi XR(®), i.e., involving immediate release of TPM in initial release stage followed by a sustained release up to 24 h. Moreover, the impact of the pH of release medium on the drug release rate of TPM sustained-release pellets was not significant. The release mechanism of TPM from the sustained-release pellets might be the interaction of diffusion (coating-film) and corrosion (drug layer). The in vivo pharmacokinetics results showed the TPM sustained-release pellets had the similar in vivo pattern compared with Trokendi XR(®). These studies provide valuable basis for further development of TPM sustained-release pellets. PMID:26563941

  8. Comparison of multiple genes and 16S-23S rRNA intergenic space region for their capacity in high resolution melt curve analysis to differentiate Mycoplasma gallisepticum vaccine strain ts-11 from field strains.

    PubMed

    Ghorashi, Seyed A; Bradbury, Janet M; Ferguson-Noel, Naola M; Noormohammadi, Amir H

    2013-12-27

    Mycoplasma gallisepticum (MG) is an important avian pathogen causing significant economic losses in the global poultry industry. In an attempt to compare and evaluate existing genotyping methods for differentiation of MG strains/isolates, high resolution melt (HRM) curve analysis was applied to 5 different PCR methods targeting vlhA, pvpA, gapA, mgc2 genes and 16S-23S rRNA intergenic space region (IGSR). To assess the discriminatory power of PCR-HRM of examined genes and IGSR, MG strains ts-11, F, 6/85 and S6, and, initially, 8 field isolates were tested. All MG strains/isolates were differentiated using PCR-HRM curve analysis and genotype confidence percentage (GCP) values of vlhA and pvpA genes, while only 0, 3 and 4 out of 12 MG strains/isolates were differentiated using gapA, mgc2 genes and IGSR, respectively. The HRM curve analysis of vlhA and pvpA genes was found to be highly correlated with the genetic diversity of the targeted genes confirmed by sequence analysis of amplicons generated from MG strains. The potential of the vlhA and pvpA genes was also demonstrated for genotyping of 12 additional MG strains from Europe and the USA. Results from this study provide a direct comparison between genes previously used in sequencing-based genotyping methods for MG strain identification and highlight the usefulness of vlhA and pvpA HRM curve analyses as rapid and reliable tools specially for diagnosis and differentiation of MG strains used here. PMID:24238667

  9. Rheological Characterization of Ethanolamine Gel Propellants

    NASA Astrophysics Data System (ADS)

    V. S Jyoti, Botchu; Baek, Seung Wook

    2016-07-01

    Ethanolamine is considered to be an environmentally friendly propellant system because it has low toxicity and is noncarcinogenic in nature. In this article, efforts are made to formulate and prepare ethanolamine gel systems, using pure agarose and hybrids of paired gelling agents (agarose + polyvinylpyrrolidine (PVP), agarose + SiO2, and PVP + SiO2), that exhibit a measurable yield stress, thixotropic behavior under shear rate ranges of 1-1,000 s-1 and a viscoelastic nature. To achieve these goals, multiple rheological experiments (including flow and dynamic studies) are performed. In this article, results are presented from experiments measuring the apparent viscosity, yield stress, thixotropy, dynamic strain, frequency sweep, and tan δ behaviors, as well as the effects of the test temperature, in the gel systems. The results show that the formulated ethanolamine gels are thixotropic in nature with yield stress between 30 and 60 Pa. The apparent viscosity of the gel decreases as the test temperature increases, and the apparent activation energy is the lowest for the ethanolamine-(PVP + SiO2) gel system. The dynamic rheology study shows that the type of gellant, choice of hybrid gelling materials and their concentration, applied frequencies, and strain all vitally affect the viscoelastic properties of the ethanolamine gel systems. In the frequency sweep experiment, the ethanolamine gels to which agarose, agarose + PVP, and agarose + SiO2 were added behave like linear frequency-dependent viscoelastic liquids, whereas the ethanolamine gel to which PVP + SiO2 was added behaves like a nearly frequency-independent viscoelastic solid. The variation in the tan δ of these gelled propellants as a function of frequency is also discussed.

  10. Morphological evolution of carbon nanofibers encapsulating SnCo alloys and its effect on growth of the solid electrolyte interphase layer.

    PubMed

    Shin, Jungwoo; Ryu, Won-Hee; Park, Kyu-Sung; Kim, Il-Doo

    2013-08-27

    Two distinctive one-dimensional (1-D) carbon nanofibers (CNFs) encapsulating irregularly and homogeneously segregated SnCo nanoparticles were synthesized via electrospinning of polyvinylpyrrolidone (PVP) and polyacrylonitrile (PAN) polymers containing Sn-Co acetate precursors and subsequent calcination in reducing atmosphere. CNFs synthesized with PVP, which undergoes structural degradation of the polymer during carbonization processes, exhibited irregular segregation of heterogeneous alloy particles composed of SnCo, Co3Sn2, and SnO with a size distribution of 30-100 nm. Large and exposed multiphase SnCo particles in PVP-driven amorphous CNFs (SnCo/PVP-CNFs) kept decomposing liquid electrolyte and were partly detached from CNFs during cycling, leading to a capacity fading at the earlier cycles. The closer study of solid electrolyte interphase (SEI) layers formed on the CNFs reveals that the gradual growth of fiber radius due to continuous increment of SEI layer thickness led to capacity fading. In contrast, SnCo particles in PAN-driven CNFs (SnCo/PAN-CNFs) showed dramatically reduced crystallite sizes (<10 nm) of single phase SnCo nanoparticles which were entirely embedded in dense, semicrystalline, and highly conducting 1-D carbon matrix. The growth of SEI layer was limited and saturated during cycling. As a result, SnCo/PAN-CNFs showed much improved cyclability (97.9% capacity retention) and lower SEI layer thickness (86 nm) after 100 cycles compared to SnCo/PVP-CNFs (capacity retention, 71.9%; SEI layer thickness, 593 nm). This work verifies that the thermal behavior of carbon precursor is highly responsible for the growth mechanism of SEI layer accompanied with particles detachment and cyclability of alloy particle embedded CNFs. PMID:23875909

  11. Inkjet printing as a novel medicine formulation technique.

    PubMed

    Scoutaris, Nikolaos; Alexander, Morgan R; Gellert, Paul R; Roberts, Clive J

    2011-12-10

    We demonstrate the viability of using an ink-jet printer to produce a formulation capable of controlling the release of a drug. This is shown for the drug felodipine, an antihypertensive, with polyvinyl pirrolidone (PVP) as an excipient. As felodipine is a poorly water soluble drug, its molecular dispersion in a soluble polymer (ie. PVP) is a commonly used approach to improve bioavailability. Various ratios of felodipine and PVP in an ethanol-DMSO mixture (95/5) were dispensed in picoliter quantities using a piezoelectric 'ink-jet' head onto a hydrophobic substrate. The resultant formulation spots were characterized using atomic force microscopy, localized nano-thermal analysis, ATR-IR and imaging confocal Raman spectroscopy. Intimate mixing of the felodipine and PVP within the micro-dots was observed. ATR-IR confirmed the known molecular level interaction of felodipine and PVP through hydrogen bonding. Nanothermal analysis indicated a single glass transition point, indicative of an intimate polymer drug mixture, which is lowered as the drug concentration increases. Confocal Raman microscopy mapping on single micro-scale droplets allowed the visualization of the drug distribution in the spots as well as facilitating characterization of the release of the drug. The drug release can be altered through control of the drug loading. As inkjet printing is an inherently scalable technology, this proof of principal work with single deposited micro-spot formulations demonstrates the potential of this approach to print practical dosage forms (e.g. as an array of many thousands of spots with different release profiles). This, for example, raises the possibility in the future of producing dosage forms at points of care with one or more drugs which have been formulated for the needs of individual patients. PMID:21827800

  12. Laparoscopic urinary bladder diverticulectomy combined with photoselective vaporisation of the prostate

    PubMed Central

    Eret, Viktor; Stránský, Petr; Trávníček, Ivan; Dolejšová, Olga; Chudáček, Zdeněk; Petersson, Fredrik; Hes, Ondřej; Chłosta, Piotr

    2015-01-01

    Introduction Pseudodiverticulum of the urinary bladder is mostly a complication of subvesical obstruction (SO). The gold standard of treatment was open diverticulectomy with adenectomy. A more contemporary resolution is endoscopic, in two steps: the first transurethral resection of the prostate (TURP), the second laparoscopic diverticulectomy (LD). Aim To present a one-session procedure – photoselective vaporisation of the prostate (PVP) with LD. Material and methods From 1/2011 to 6/2014, 14 LDs were performed: 1 LD only, 1 with laparoscopic radical prostatectomy, 12 combined with treatment of benign prostatic hyperplasia (BPH), 4 cases of TURP and LD in the second period. In 8 cases, PVP and LD in one session were combined. These 8 cases are presented. 3D CT cystography was used as a gold standard for assessment of diverticulum. Results The mean age was 66.5 ±5.5 (57.3–75.1) years, the mean size of the diverticulum 61.8 ±22.1 (26–90) mm. The procedure starts in the lithotomy position. It includes PVP and stenting of the ureter(s). Changing of position and laparoscopy follows: four ports, transperitoneal extravesical approach. Photoselective vaporisation of the prostate was performed using the Green Light Laser HPS (1x) or XPS with cooled fibre MoXy (7x). The mean delivered energy in PVP was 205.1 ±106.4 (120–458) kJ. The mean time of operation was 165.0 ±48.5 (90–255) min. No postoperative complications were observed. One patient underwent TUR incision after 1 year for sclerosis of the bladder neck. Conclusions Pseudodiverticulum of the urinary bladder (with or without SO) is a relatively rare disease. One session of PVP (Green Light Laser XPS, MoXy fibre) and laparoscopic (transperitoneal extravesical) diverticulectomy is the preferred method for treatment of subvesical obstruction due to BPH and bladder diverticulum at our institution. PMID:25960795

  13. Impact of surface coating and environmental conditions on the fate and transport of silver nanoparticles in the aquatic environment.

    PubMed

    Ellis, Laura-Jayne A; Valsami-Jones, Eugenia; Lead, Jamie R; Baalousha, Mohammed

    2016-10-15

    The role of surface coating (polyvinylpyrrolidone (PVP) and citrate) and water chemistry on the fate and behavior of AgNPs in aquatic microcosms is reported in this study. The migration and transformation of the AgNPs was examined in low (ultrapure water-UPW) and high ionic strength (moderately hard water - MHW) preparations, and in the presence of modeled natural organic matter (NOM) of Suwannee River Fulvic Acid (SRFA). The migration and fate of the AgNPs in the microcosms was validated using a sedimentation-diffusion model and the aggregation behavior was monitored by UV-visible spectrometry (UV-vis). Dissolved and particulate Ag concentrations (% Ag) were analyzed by ultrafiltration methods. Imaging of the AgNPs was captured using transmission electron microscopy (TEM). Results indicate that PVP-coated AgNPs (PVP-AgNPs) remained stable for 28days with similarly distributed concentrations of the PVP-AgNPs throughout the columns in each of the water conditions after approximately 96h (4days). The sedimentation-diffusion model confirmed PVP-AgNP stability in each condition, by showing diffusion dominated transport by using the original unaltered AgNP sizes to fit the parameters. In comparison, citrate AgNPs were largely unstable in the more complex water preparations (MHW). In MHW, aggregation dominated behavior followed by sedimentation/dissolution controlled transport was observed. The addition of SRFA to MHW resulted in small stabilizing effects, to the citrate coated AgNPs, producing smaller sized AgNPs (TEM) and mixed sedimentation and diffusion migration compared the studies absent of SRFA. The results suggest that surface coating and solution chemistry has a major impact on AgNP stability, furthermore the corresponding modeling will support the experimental understanding of the overall fate of AgNPs in the environment. PMID:27289392

  14. Application of Solid-State NMR Relaxometry for Characterization and Formulation Optimization of Grinding-Induced Drug Nanoparticle.

    PubMed

    Ueda, Keisuke; Higashi, Kenjirou; Moribe, Kunikazu

    2016-03-01

    The formation mechanism of drug nanoparticles was investigated using solid-state nuclear magnetic resonance (NMR) techniques for the efficient discovery of an optimized nanoparticle formulation. The cogrinding of nifedipine (NIF) with polymers, including hydroxypropyl methylcellulose (HPMC) and polyvinylpyrrolidone (PVP), and sodium dodecyl sulfate (SDS) was performed to prepare the NIF nanoparticle formulations. Then, solid-state NMR relaxometry was used for the nanometer-order characterization of NIF in the polymer matrix. Solid-state NMR measurements revealed that the crystal size of NIF was reduced to several tens of nanometers with amorphization of NIF by cogrinding with HPMC and SDS for 100 min. Similarly, the size of the NIF crystal was reduced to less than 90 nm in the 40 min ground mixture of NIF/PVP/SDS. Furthermore, 100 min grinding of NIF/PVP/SDS induced amorphization of almost all the NIF crystals followed by nanosizing. The hydrogen bond between NIF and PVP led to the efficient amorphization of NIF in the NIF/PVP/SDS system compared with NIF/HPMC/SDS system. The efficient nanosizing of the NIF crystal in the solid state, revealed by the solid-state NMR relaxation time measurements, enabled the formation of large amounts of NIF nanoparticles in water followed by the polymer dissolution. In contrast, excess amorphization of the NIF crystals failed to efficiently prepare the NIF nanoparticles. The solid-state characterization of the crystalline NIF revealed good correlation with the NIF nanoparticles formation during aqueous dispersion. Furthermore, the solid-state NMR measurements including relaxometry successfully elucidated the nanometer-order dispersion state of NIF in polymer matrix, leading to the discovery of optimized conditions for the preparation of suitable drug nanoparticles. PMID:26855230

  15. Stability and solubility enhancement of ellagic acid in cellulose ester solid dispersions.

    PubMed

    Li, Bin; Harich, Kim; Wegiel, Lindsay; Taylor, Lynne S; Edgar, Kevin J

    2013-02-15

    Structurally varied, carboxyl-containing cellulose derivatives were evaluated for their ability to form amorphous solid dispersions (ASD) with ellagic acid (EA), in order to improve the solubility of this high-melting, poorly bioavailable, but highly bioactive natural flavonoid compound. ASDs of EA with carboxymethylcellulose acetate butyrate (CMCAB), cellulose acetate adipate propionate (CAAdP), and hydroxypropylmethylcellulose acetate succinate (HPMCAS) were prepared, and EA dissolution from these ASDs was compared with that from pure crystalline EA and from EA/poly(vinylpyrrolidinone) (PVP) solid dispersions (SD). Polymer/drug mixtures were characterized by powder X-ray diffraction (XRPD), modulated differential scanning calorimetry (MDSC), nuclear magnetic resonance (NMR) and Fourier transform infrared spectroscopy (FT-IR). The XRPD and FT-IR results indicated that EA was amorphous in solid dispersions with EA concentration up to 25 wt%. The stability against crystallization and solution concentrations of EA from these solid dispersions were significantly higher than those observed for physical mixtures and pure crystalline EA. HPMCAS stabilized EA most effectively, among the polymers tested, against both chemical degradation and recrystallization. The relative ability to solubilize EA from ASDs at pH 6.8 was PVP>HPMCAS>CMCAB. EA dissolves from ASD in PVP quickly and completely (maximum 92%) at pH 6.8, but EA is also released from PVP at pH 1.2, and then crystallizes rapidly. Therefore PVP is not a practical candidate for EA ASD. In contrast, the cellulose derivative ASDs show very slow EA release at pH 1.2 (<4%) and faster but still incomplete drug release at pH 6.8 (maximum 35% for HPMCAS SD). The pH-triggered drug release from HPMCAS ASD makes HPMCAS a practical choice for EA solubility enhancement. PMID:23399175

  16. Highly grafted polystyrene/polyvinylpyridine polymer gold nanoparticles in a good solvent: effects of chain length and composition.

    PubMed

    Posel, Zbyšek; Posocco, Paola; Lísal, Martin; Fermeglia, Maurizio; Pricl, Sabrina

    2016-04-21

    In this work, the structural features of spherical gold nanoparticles (NPs) decorated with highly grafted poly(styrene) (PS), poly(vinylpyridine) (PVP) and PS-PVP diblock copolymer brushes immersed in a good solvent are investigated by means of Dissipative Particle Dynamics (DPD) simulations as a function of grafted chain length and of homopolymer and copolymer chain composition. For NPs grafted either by PS or PVP homopolymer brushes (selected as a proof of concept), good agreement between the Daoud-Cotton theory, experimental evidence, and our DPD simulations is observed in the scaling behavior of single chain properties, especially for longer grafted chains, and in brush thickness prediction. On the other hand, for grafted chain lengths comparable to NP dimensions parabolic-like profiles of the end-monomer distributions are obtained. Furthermore, a region of high concentration of polymer segments is observed in the monomer density distribution for long homopolymers. In the case of copolymer-decorated NPs, the repulsion between PS and PVP blocks is found to substantially influence the radius of gyration and the shape of the end-monomer distribution of the relevant polymer shell. Moreover, for diblock chains, the un-swollen region is observed to be thinner (and, correspondingly, the swollen layer thicker) than that of a NP modified with a homopolymer of the same length. Finally, the lateral segregation of PS and PVP blocks is evidenced by our calculations and a detailed analysis of the corona behavior is reported, thus revealing the key parameters in controlling the surface properties and the response of diblock copolymer modified nanoparticles. PMID:26980360

  17. Percutaneous Vertebroplasty: Preliminary Experiences with Rotational Acquisitions and 3D Reconstructions for Therapy Control

    SciTech Connect

    Hodek-Wuerz, Roman Martin, Jean-Baptiste; Wilhelm, Kai; Lovblad, Karl O.; Babic, Drazenko; Rufenacht, Daniel A.; Wetzel, Stefan G.

    2006-10-15

    Percutaneous vertebroplasty (PVP) is carried out under fluoroscopic control in most centers. The exclusion of implant leakage and the assessment of implant distribution might be difficult to assess based on two-dimensional radiographic projection images only. We evaluated the feasibility of performing a follow-up examination after PVP with rotational acquisitions and volumetric reconstructions in the angio suite. Twenty consecutive patients underwent standard PVP procedures under fluoroscopic control. Immediate postprocedure evaluation of the implant distribution in the angio suite (BV 3000; Philips, The Netherlands) was performed using rotational acquisitions (typical parameters for the image acquisition included a 17-cm field-of-view, 200 acquired images for a total angular range of 180{sup o}). Postprocessing of acquired volumetric datasets included multiplanar reconstruction (MPR), maximum intensity projection (MIP), and volume rendering technique (VRT) images that were displayed as two-dimensional slabs or as entire three-dimensional volumes. Image evaluation included lesion and implant assessment with special attention given to implant leakage. Findings from rotational acquisitions were compared to findings from postinterventional CT. The time to perform and to postprocess the rotational acquisitions was in all cases less then 10 min. Assessment of implant distribution after PVP using rotational image acquisition methods and volumetric reconstructions was possible in all patients. Cement distribution and potential leakage sites were visualized best on MIP images presented as slabs. From a total of 33 detected leakages with CT, 30 could be correctly detected by rotational image acquisition. Rotational image acquisitions and volumetric reconstruction methods provided a fast method to control radiographically the result of PVP in our cases.

  18. In vivo evaluation of different formulation strategies for sustained release injectables of a poorly soluble HIV protease inhibitor.

    PubMed

    Meeus, Joke; Scurr, David J; Amssoms, Katie; Wuyts, Koen; Annaert, Pieter; Davies, Martyn C; Roberts, Clive J; Van den Mooter, Guy

    2015-02-10

    At present no scientific rationale exists for selecting a particular enabling strategy to formulate a poorly water-soluble drug, although this is crucial as it will influence the in vivo performance of the resulting formulation. This study provides an insight into this complicated decision making process for a poorly soluble human immunodeficiency virus (HIV) protease inhibitor based upon in vivo test results. A formulation strategy based on the molecular dispersion of this active pharmaceutical ingredient (API) into a biphasic matrix consisting of water-insoluble poly(lactic-co-glycolic acid) (PLGA) and water-soluble polyvinylpyrrolidone (PVP) was evaluated. The long-term in vivo performance of this strategy was compared to that of other solubility enhancing approaches by evaluating exposure of the API in male Beagle dogs. Solid dispersions, based on a PLGA/PVP matrix, were compared to solid dispersions in a pure PLGA matrix. Additionally these solid dispersion strategies were compared to the strategy of particle size reduction by means of an API microsuspension. The in vivo performance of the various formulations over a period of 28days after intramuscular injection was evaluated by the observed initial burst release, plasma concentration-time profiles, time at which maximum plasma levels were reached and the estimated bioavailability. Compared to the other formulation strategies assessed, it was concluded that the addition of PVP in a PLGA matrix resulted in vivo in a more sustained release as well as a higher amount of drug released from the polymeric matrix. This was explained based on the structure of these binary PLGA/PVP matrices where the pore network originating from rapidly dissolving PVP plays a key role. Moreover, the results suggest that the API release from this type of formulation could be delayed by increasing the amount of PLGA in the formulation. PMID:25485732

  19. Photoselective vaporization of prostate vs. transurethral resection of prostate: A prospective, randomized study with one year follow-up

    PubMed Central

    Mohanty, Nayan K.; Vasudeva, Pawan; Kumar, Anup; Prakash, Sanjay; Jain, Manoj; Arora, Rajender P.

    2012-01-01

    Objectives: To evaluate in a prospective, randomized study, the efficacy and safety profile of photoselective vaporization of prostate (PVP) using a 80W potassium titanyl phosphate (KTP) laser when compared to standard transurethral resection of prostate (TURP) in patients with lower urinary tract symptoms (LUTS) due to benign prostatic enlargement (BPE). Materials and Methods: Between February 2009 and August 2009, 117 patients satisfying the eligibility criteria underwent surgery [60 PVP{Group A}; 57 TURP{Group B}]. The groups were compared for functional outcome (both subjective and objective parameters), perioperative parameters and complications, with a follow up of one year. P value<0.05 was considered statistically significant. Results: The baseline characteristics of the two groups were comparable. Mean age was 66.68 years and 65.74 years, mean IPSS score was 19.98 and 20.88, mean prostate volume was 44.77 cc and 49.02 cc in Group A and B, respectively. Improvements in IPSS, QOL, prostate volume, Q max and PVRU at 12 months were similar in both groups. PVP patients had longer operating time, lesser perioperative blood loss, shorter catheterization time and a higher dysuria rate when compared to TURP patients. The overall complication rate was similar in the two groups. Conclusions: In patients with LUTS due to BPE, KTP-PVP is an equally efficacious alternative to TURP with durable results at one year follow up with additional benefits of lesser perioperative blood loss, lesser transfusion requirements and a shorter catheterization time. Long term comparative data is awaited to clearly define the role of KTP-PVP in such patients. PMID:23204660

  20. Toxicity, bioaccumulation, and biotransformation of silver nanoparticles in marine organisms.

    PubMed

    Wang, Huanhua; Ho, Kay T; Scheckel, Kirk G; Wu, Fengchang; Cantwell, Mark G; Katz, David R; Horowitz, Doranne Borsay; Boothman, Warren S; Burgess, Robert M

    2014-12-01

    The toxicity, bioaccumulation, and biotransformation of citrate and polyvinylpyrrolidone (PVP) coated silver nanoparticles (NPs) (AgNP-citrate and AgNP-PVP) in marine organisms via marine sediment exposure was investigated. Results from 7-d sediment toxicity tests indicate that AgNP-citrate and AgNP-PVP did not exhibit toxicity to the amphipod (Ampelisca abdita) and mysid (Americamysis bahia) at ≤75 mg/kg dry wt. A 28-d bioaccumulation study showed that Ag was significantly accumulated in the marine polychaete Nereis virens (N. virens) in the AgNP-citrate, AgNP-PVP and a conventional salt (AgNO3) treatments. Synchrotron X-ray absorption spectroscopy (XAS) results showed the distribution of Ag species in marine sediments amended with AgNP-citrate, AgNP-PVP, and AgNO3 was AgCl (50–65%) > Ag2S (32–42%) > Ag metal (Ag0) (3–11%). In N virens, AgCl (25–59%) and Ag2S (10–31%) generally decreased and, Ag metal (32–44%) increased, relative to the sediments. The patterns of speciation in the worm were different depending upon the coating of the AgNP and both types of AgNPs were different than the AgNO3 salt. These results show that the AgNP surface capping agents influenced Ag uptake, biotransformation, and/or excretion. To our knowledge, this is the first demonstration of the bioaccumulation and speciation of AgNPs in a marine organism (N. virens). PMID:25369427

  1. Photoselective green-light laser vaporisation vs. TURP for BPH: meta-analysis

    PubMed Central

    Ding, Hui; Du, Wan; Lu, Ze-Ping; Zhai, Zhen-Xing; Wang, Han-Zhang; Wang, Zhi-Ping

    2012-01-01

    This study sought to evaluate the efficacy and safety of photoselective vaporisation (PVP) vs. transurethral resection of the prostate (TURP) for patients with benign prostatic hyperplasia (BPH). Eligible studies were identified from electronic databases (Cochrane Library, PubMed and EMBASE). The database search, quality assessment and data extraction were performed independently by two reviewers. Efficacy (primary outcomes: maximum urinary flow rate (Qmax), international prostate symptom score (IPSS), postvoid residual urine (PVR) and quality of life (QoL); secondary outcomes: operative time, hospital time and catheter removal time) and safety (complications, such as transfusion and capsular perforation) were explored by using Review Manager 5.0. Six randomized controlled trials (RCTs) and five case-controlled studies of 1398 patients met the inclusion criteria. A meta-analysis of the extractable data showed that there were no differences in IPSS, Qmax, QoL or PVR between PVP and TURP (mean difference (MD): prostate sizes <70 ml, Qmax at 24 months, MD=0.01, P=0.97; IPSS at 12 months, MD=0.18, P=0.64; QoL at 12 months, MD=−0.00, P=0.96; PVR at 12 months, MD=0.52, P=0.43; prostate sizes >70 ml, Qmax at 6 months, MD=−3.46, P=0.33; IPSS at 6 months, MD=3.11, P=0.36; PVR at 6 months, MD=25.50, P=0.39). PVP was associated with a shorter hospital time and catheter removal time than TURP, whereas PVP resulted in a longer operative time than TURP. For prostate sizes <70 ml, there were fewer transfusions, capsular perforations, incidences of TUR syndrome and clot retentions following PVP compared with TURP. These results indicate that PVP is as effective and safe as TURP for BPH at the mid-term patient follow-up, in particular for prostate sizes <70 ml. Due to the different energy settings available for green-light laser sources and the higher efficiency and performance of higher-quality lasers, large-sample, long-term RCTs are required to verify whether different

  2. Glass Transition and Dynamics of the Polymer and Water in the Poly(vinylpyrrolidone)-Water Mixtures Studied by Dielectric Relaxation Spectroscopy.

    PubMed

    Sasaki, Kaito; Matsui, Yurika; Miyara, Masahiko; Kita, Rio; Shinyashiki, Naoki; Yagihara, Shin

    2016-07-14

    In this study, broadband dielectric spectroscopy and differential scanning calorimetry (DSC) measurements are performed to study the dynamics of water and polymers in an aqueous solution of poly(vinylpyrrolidone) (PVP) with concentrations of 60, 65, and 70 wt % PVP in a temperature range of 123-298 K. Two distinct relaxation processes, l- and h-processes, which originate from the segmental chain motion of PVP and the primary relaxation process of water, respectively, are observed simultaneously. The relationship between l- and h-processes and their temperature dependences mimic those of the α-process and Johari-Goldstein β-process, which are observed in ordinal glass formers. The relaxation time of the l-process, τl, obeys the Vogel-Fulcher (VF)-type temperature dependence, and the glass-transition temperature of the l-process, Tg,l, which is defined by the temperature that is reached in a τl of 100-1000 s, shows good agreement with the calorimetric Tg obtained by DSC. The temperature dependence of the relaxation time of the h-process, τh, exhibits a crossover from VF to Arrhenius behavior at the so-called fragile-to-strong transition (FST) of water at Tg,l. The temperature dependence of the relaxation strength of the h-process, Δεh, increases with a decrease in temperature from 298 K to Tg,l. Below Tg,l, Δεh is nearly constant or slightly decreases with decreasing temperature. According to previous studies on aqueous solutions of sugars and alcohols, the Δε of the ν-process, which originates from local motion of water, decreases with decreasing temperature above the Tg of the α-process, which originates from the cooperative motion of the solute and water. Therefore, the l-process in the PVP-water mixture is not a result of the cooperative motion of PVP and water but rather a result of the polymer-polymer cooperative motion of PVP. In addition, agreement among Tg,l, the temperature of the FST of water, and calorimetric Tg suggests that the FST of water

  3. [Contribution of Particle Size and Surface Coating of Silver Nanoparticles to Its Toxicity in Marine Diatom Skeletonema costatum].

    PubMed

    Huang, Jun; Yi, Jun; Qiang, Li-yuan; Cheng, Jin-ping

    2016-05-15

    Due to the unique antibacterial properties, silver nanoparticles (AgNPs) have been widely used in commercial applications. In this study, the toxicity of three kinds of AgNPs with different sizes and surface coatings to marine diatom Skeletonema costatum (S. costatum) was studied, which was one of the dominant species in estuarine and coastal areas. All three kinds of tested AgNPs inhibited the growth of exposed S. costatum under acute exposure condition, and the order of toxicity was 10 nm-OA > 10 nm-PVP > 20 nm-PVP. Given the condition of similar particle size, oil amine surface coated AgNPs were more toxic than polyvinyl pyrrolidone (PVP) surface coated AgNPs in S. costatum in term of cytotoxicity. With the same surface coating, the toxicity of AgNPs in S. costatum was affected by its hydrodynamic diameter and exposure concentrations. When the concentration of AgNPs was less than 500 µg · L⁻¹, larger sized AgNPs showed greater toxicity; When the concentration was greater than or equal to 500 µg · L⁻¹, smaller AgNPs exhibited greater toxicity. At molecular level, 50 µg · L⁻¹ 10nm-PVP significantly upregulated expression level of 3HfcpA (P < 0.05) and significantly downregulated expression level of Dl (P < 0.05), and 500 µg · L⁻¹ 10nm-OA significantly upregulated 3HfcpA expression (P < 0.05), while 20 nm-PVP treatment group didn't show any significant change. Exposed diatom demonstrated sensitive photosynthesis response to small size and PVP coated silver nanoparticles at molecular level. This study suggested that the toxicity of AgNPs to marine microalgae was largely controlled by the particle size, surface coating, exposure medium, exposure concentration and other factors. The smaller the particle size, the greater the toxicity of AgNPs, and the particle size of AgNPs played an important role in the toxicity of AgNPs in marine diatom S. costatum. PMID:27506055

  4. Self-constructed tree-shape high thermal conductivity nanosilver networks in epoxy

    NASA Astrophysics Data System (ADS)

    Pashayi, Kamyar; Fard, Hafez Raeisi; Lai, Fengyuan; Iruvanti, Sushumna; Plawsky, Joel; Borca-Tasciuc, Theodorian

    2014-03-01

    We report the formation of high aspect ratio nanoscale tree-shape silver networks in epoxy, at low temperatures (<150 °C) and atmospheric pressures, that are correlated to a ~200 fold enhancement of thermal conductivity (κ) of the nanocomposite compared to the polymer matrix. The networks form through a three-step process comprising of self-assembly by diffusion limited aggregation of polyvinylpyrrolidone (PVP) coated nanoparticles, removal of PVP coating from the surface, and sintering of silver nanoparticles in high aspect ratio networked structures. Controlling self-assembly and sintering by carefully designed multistep temperature and time processing leads to κ of our silver nanocomposites that are up to 300% of the present state of the art polymer nanocomposites at similar volume fractions. Our investigation of the κ enhancements enabled by tree-shaped network nanocomposites provides a basis for the development of new polymer nanocomposites for thermal transport and storage applications.We report the formation of high aspect ratio nanoscale tree-shape silver networks in epoxy, at low temperatures (<150 °C) and atmospheric pressures, that are correlated to a ~200 fold enhancement of thermal conductivity (κ) of the nanocomposite compared to the polymer matrix. The networks form through a three-step process comprising of self-assembly by diffusion limited aggregation of polyvinylpyrrolidone (PVP) coated nanoparticles, removal of PVP coating from the surface, and sintering of silver nanoparticles in high aspect ratio networked structures. Controlling self-assembly and sintering by carefully designed multistep temperature and time processing leads to κ of our silver nanocomposites that are up to 300% of the present state of the art polymer nanocomposites at similar volume fractions. Our investigation of the κ enhancements enabled by tree-shaped network nanocomposites provides a basis for the development of new polymer nanocomposites for thermal transport

  5. Poly(lactic acid)-poly(ethylene glycol) nanoparticles as new carriers for the delivery of plasmid DNA.

    PubMed

    Perez, C; Sanchez, A; Putnam, D; Ting, D; Langer, R; Alonso, M J

    2001-07-10

    The purpose of the present work was to produce and characterize poly(lactic acid)-poly(ethylene glycol) (PLA-PEG) nanoparticles (size lower than 300 nm) containing a high loading of plasmid DNA in a free form or co-encapsulated with either poly(vinyl alcohol) (PVA) or poly(vinylpyrrolidone) (PVP). The plasmid alone or with PVA or PVP was encapsulated by two different techniques: an optimized w/o/w emulsion-solvent evaporation technique as well as by a new w/o emulsion-solvent diffusion technique. Particle size, zeta potential, plasmid DNA loading and in vitro release were determined for the three plasmid-loaded formulations. The influence of the initial plasmid loadings (5, 10, 20 microg plasmid DNA/mg PLA-PEG) on those parameters was also investigated. The plasmid loaded into the nanoparticles and released in vitro was quantified by fluorimetry and the different molecular forms were identified by gel electrophoresis. PLA-PEG nanoparticles containing plasmid DNA in a free form or co-encapsulated with PVA or PVP were obtained in the range size of 150-300 nm and with a negative zeta potential, both parameters being affected by the preparation technique. Encapsulation efficiencies were high irrespective of the presence of PVA or PVP (60-90%) and were slightly affected by the preparation technique and by the initial loading. The final plasmid DNA loading in the nanoparticles was up to 10-12 microg plasmid DNA/mg polymer. Plasmid DNA release kinetics varied depending on the plasmid incorporation technique: nanoparticles prepared by the w/o diffusion technique released their content rapidly whereas those obtained by the w/o/w showed an initial burst followed by a slow release for at least 28 days. No significant influence of the plasmid DNA loading and of the co-encapsulation of PVP or PVA on the in vitro release rate was observed. In all cases the conversion of the supercoiled form to the open circular and linear forms was detected. In conclusion, plasmid DNA can be

  6. Tunable biphasic drug release from ethyl cellulose nanofibers fabricated using a modified coaxial electrospinning process

    NASA Astrophysics Data System (ADS)

    Li, Chen; Wang, Zhuan-Hua; Yu, Deng-Guang; Williams, Gareth R.

    2014-05-01

    This manuscript reports a new type of drug-loaded core-shell nanofibers that provide tunable biphasic release of quercetin. The nanofibers were fabricated using a modified coaxial electrospinning process, in which a polyvinyl chloride (PVC)-coated concentric spinneret was employed. Poly (vinyl pyrrolidone) (PVP) and ethyl cellulose (EC) were used as the polymer matrices to form the shell and core parts of the nanofibers, respectively. Scanning and transmission electron microscopy demonstrated that the nanofibers had linear morphologies and core-shell structures. The quercetin was found to be present in the nanofibers in the amorphous physical status, on the basis of X-ray diffraction results. In vitro release profiles showed that the PVP shell very rapidly freed its drug cargo into the solution, while the EC core provided the succedent sustained release. Variation of the drug loading permitted the release profiles to be tuned.

  7. A complementary switching mechanism for organic memory devices to regulate the conductance of binary states

    NASA Astrophysics Data System (ADS)

    Vyas, Giriraj; Dagar, Parveen; Sahu, Satyajit

    2016-06-01

    We have fabricated an organic non-volatile memory device wherein the ON/OFF current ratio has been controlled by varying the concentration of a small organic molecule, 2,3-Dichloro-5,6-dicyano-p-benzoquinone (DDQ), in an insulating matrix of a polymer Poly(4-vinylphenol) (PVP). A maximum ON-OFF ratio of 106 is obtained when the concentration of DDQ is half or 10 wt. % of PVP. In this process, the switching direction for the devices has also been altered, indicating the disparity in conduction mechanism. Conduction due to metal filament formation through the active material and the voltage dependent conformational change of the organic molecule seem to be the motivation behind the gradual change in the switching direction.

  8. Shape-controlled synthesis of silver nanocrystals via γ-irradiation in the presence of poly(vinyl pyrrolidone)

    NASA Astrophysics Data System (ADS)

    Zhao, Yongbin; Chen, Aihua; Liang, Shu

    2013-06-01

    Silver nanocrystals with controlled morphologies were facilely synthesized via γ-irradiation on aqueous solutions containing AgNO3 and poly(vinyl pyrrolidone)(PVP) by adjusting the adsorption dose. UV-vis spectroscopy, TEM, XRD and X-ray photoelectron spectroscopy were used to characterize these silver nanocrystals. Spherical silver nanoparticles with diameter of ˜20 nm were formed irradiated by γ-ray with dose of 12 kGy, and one-dimensional silver nanowires with average diameter of 30 nm and length up to 20-30 μm were obtained with dose increased to 36 kGy. In this process, γ-ray and PVP have synergistic effects on the formation of silver nanocrystals, leading to the formation of highly pure phase, as well as a uniform size of each structure.

  9. Assembly of poly(dopamine) films mixed with a nonionic polymer.

    PubMed

    Zhang, Yan; Thingholm, Bo; Goldie, Kenneth N; Ogaki, Ryosuke; Städler, Brigitte

    2012-12-21

    Poly(dopamine) (PDA) coatings have recently attracted considerable interest for a variety of applications. Here, we investigate the film deposition of dopamine mixed with a nonionic polymer (i.e., poly(ethylene glycol) (PEG), poly(vinyl alcohol) (PVA), and poly(N-vinyl pyrrolidone) (PVP)) onto silica substrates using X-ray photoelectron spectroscopy and quartz crystal microbalance. Furthermore, we assess the possibility of coating silica colloids to yield polymer capsules and liposomes with these mixtures. We found that mixed PDA/PEG and PDA/PVA films are deposited without the need for a covalent linker such as an amine or thiol. We also discovered the first material, namely, PVP, that can suppress PDA film assembly. These fundamental findings give further insight into PDA film properties and contribute to establish PDA as a widely applicable coating. PMID:23205620

  10. Influence of the counterion on the synthesis of ZnO mesocrystals under solvothermal conditions.

    PubMed

    Distaso, Monica; Klupp Taylor, Robin N; Taccardi, Nicola; Wasserscheid, Peter; Peukert, Wolfgang

    2011-03-01

    Polymers and coordinating solvents have been shown to serve as templating agents to assist the precipitation of ZnO nanoparticles and address their morphology. In this work we show for the first time that a difference in the coordination strength between the polymer (poly-N-vinylpyrrolidone (PVP)) and the two Zn(II) precursor salts (nitrate and acetate) is able to promote or suppress the formation of mesocrystalline structures and even more importantly to tune their three-dimensional organization. On the basis of FTIR and (13)C NMR spectroscopic studies, we propose that not only the polymer (PVP) but also the solvent (DMF) play a key role as directing agents. PMID:21294196

  11. The cellular basis of immunosuppression caused by the radiation leukaemia virus

    PubMed Central

    Peled, A.; Haran-Ghera, N.

    1974-01-01

    Infection of adult C57B1/6 mice with the radiation leukaemia virus resulted in suppression of the ability of the animals to respond to an immunizing inoculum of sheep erythrocytes. Results of the transfer experiments indicated that the immunosuppressive effect was expressed at the immunocompetent cell level, and that the virus affected the thymus-derived population of immunocytes. The immunosuppressive effect of the virus on thymus cells, independent of any contribution by cells of bone marrow origin, was verified with thymus-independent immunogens, polyvinylpyrrolidone (PVP) or pneumococcal polysaccharide SIII (PPS). Mice inoculated with the radiation leukaemia virus produced nearly normal amounts of plaque-forming cells producing antibodies against PVP and PPS, thereby confirming that the immunosuppressive effect of the radiation leukaemia virus was on thymus-derived cells. PMID:4369273

  12. A simple approach to the synthesis of eccentric Au@SiO2 Janus nanostructures and their catalytic applications

    NASA Astrophysics Data System (ADS)

    Zhao, Yang; Yang, Di; Hu, Huicheng; Chen, Lei; Xu, Yong; Qu, Lili; Yang, Peipei; Zhang, Qiao

    2016-06-01

    In this paper, we present a simple method to synthesize eccentric Au@SiO2 Janus nanoparticles. By simply tuning the concentration of poly(vinyl pyrrolidone) (PVP), the surface of gold nanoparticle can be partially or fully wrapped with the amphiphilic ligand. As a result, Janus nanoparticle or concentric core-shell nanostructures can be obtained, respectively. A systematic study has been carried out to confirm the function of PVP molecules. The as-prepared Janus nanoparticle can act as a catalyst to catalyze the reduction of 4-nitrophenol, while the core-shell nanostructure is not active due to the coverage of dense silica shell. This work provides a robust and scalable method to produce Au@SiO2 Janus nanoparticles.

  13. From Dispersed Microspheres to Interconnected Nanospheres: Carbon-Sandwiched Monolayered MoS2 as High-Performance Anode of Li-Ion Batteries.

    PubMed

    Shao, Jie; Qu, Qunting; Wan, Zhongming; Gao, Tian; Zuo, Zhichen; Zheng, Honghe

    2015-10-21

    Hierarchical structured carbon@MoS2 (C@MoS2) microspheres and nanospheres composed of carbon-sandwiched monolayered MoS2 building blocks are synthesized through a facile one-pot polyvinylpyrrolidone (PVP) micelle-assisted hydrothermal route. The dimension and carbon content of C@MoS2 spheres are effectively controlled by singly adjusting the concentration of PVP, which plays the dual functions of soft-template and carbon source. As the anode materials of Li-ion batteries, C@MoS2 nanospheres present considerably higher capacity, better rate behavior and cycling stability than C@MoS2 microspheres. The reasons are attributed to the unique interconnected nanospherical morphology and the internal hierarchical construction of C@MoS2 nanospheres with expanded MoS2/carbon interlayer spacing. PMID:26426361

  14. Tunable biphasic drug release from ethyl cellulose nanofibers fabricated using a modified coaxial electrospinning process.

    PubMed

    Li, Chen; Wang, Zhuan-Hua; Yu, Deng-Guang; Williams, Gareth R

    2014-01-01

    This manuscript reports a new type of drug-loaded core-shell nanofibers that provide tunable biphasic release of quercetin. The nanofibers were fabricated using a modified coaxial electrospinning process, in which a polyvinyl chloride (PVC)-coated concentric spinneret was employed. Poly (vinyl pyrrolidone) (PVP) and ethyl cellulose (EC) were used as the polymer matrices to form the shell and core parts of the nanofibers, respectively. Scanning and transmission electron microscopy demonstrated that the nanofibers had linear morphologies and core-shell structures. The quercetin was found to be present in the nanofibers in the amorphous physical status, on the basis of X-ray diffraction results. In vitro release profiles showed that the PVP shell very rapidly freed its drug cargo into the solution, while the EC core provided the succedent sustained release. Variation of the drug loading permitted the release profiles to be tuned. PMID:24940180

  15. Vertebral Compression Fracture with Intravertebral Vacuum Cleft Sign: Pathogenesis, Image, and Surgical Intervention

    PubMed Central

    Wu, Ai-Min; Ni, Wen-Fei

    2013-01-01

    The intravertebral vacuum cleft (IVC) sign in vertebral compression fracture patients has obtained much attention. The pathogenesis, image character and efficacy of surgical intervention were disputed. Many pathogenesis theories were proposed, and its image characters are distinct from malignancy and infection. Percutaneous vertebroplasty (PVP) or percutaneous kyphoplasty (PKP) have been the main therapeutic methods for these patients in recent years. Avascular necrosis theory is the most supported; PVP could relieve back pain, restore vertebral body height and correct the kyphotic angulation (KA), and is recommended for these patients. PKP seems to be more effective for the correction of KA and lower cement leakage. The Kümmell's disease with IVC sign reported by modern authors was incomplete consistent with syndrome reported by Dr. Hermann Kümmell. PMID:23741556

  16. Water dispersible Fe3O4 nanoparticles carrying doxorubicin for cancer therapy.

    PubMed

    Jayakumar, Onattu Damodharan; Ganguly, Rajib; Tyagi, Avesh Kumar; Chandrasekharan, Dhanya K; Nair, Cherupally K Krishnan

    2009-11-01

    Water dispersible Fe3O4 nanoparticles (coated with Poly Vinyl Pyrolidone (PVP) and Poly oxy ethylene 25-propylene glycol stearate (POES)) and complexed with Doxorubicin has been prepared and characterized using X-ray diffraction (XRD), transmission electron microscopy (TEM) and vibrating sample magnetometer (VSM). The antitumor activity of these particles has been studied by targeting the complex to the tumor site, using an externally applied magnetic field, after oral administration of the magnetic nanoparticle-drug complexes. Our results reveal that the chemotherapy effect of Doxorubicin could be considerably enhanced by combination of the application of the drug-conjugated magnetic Fe3O4 nanoparticles, which are biocompatible and stable, and targeted drug delivery with a magnet. The present report provides the first evidence for the promising application of this novel approach with PVP coated Fe3O4 nanoparticles for cancer therapy using an in vivo murine model. PMID:19908532

  17. Gastroretentive hydrodynamically balanced systems of ofloxacin: In vitro evaluation

    PubMed Central

    Nayak, Amit Kumar; Das, Biswarup; Maji, Ruma

    2011-01-01

    Hydrodynamically balanced systems (HBSs) of ofloxacin were prepared using lactose, HPMC K4M, PVP K 30, and liquid paraffin, which may increase the mean residence time in the gastrointestinal tract, and may be able to provide maximum drug at the site of absorption to improve oral bioavailability. All these formulated HBS capsules were floated well over 6 h with no floating lag time. They also showed sustained drug release over 6 h. Time for 50% release of ofloxacin was within the range, 2.47 ± 0.02 to 3.07 ± 0.08 h. The in vitro drug release from these HBS capsules was dependent on HPMC K4M, PVP K 30, and liquid paraffin content. The drug release pattern of these HBS capsules containing ofloxacin followed the Higuchi model with the anomalous transport mechanism. PMID:23960825

  18. Hypervolemia and plasma vasopressin response during water immersion in men

    NASA Technical Reports Server (NTRS)

    Greenleaf, J. E.; Morse, J. T.; Barnes, P. R.; Silver, J.; Keil, L. C.

    1983-01-01

    Immersion studies were performed on seven mildly dehydrated male subjects to examine the effect of suppression of plasma vasopressin (PVP) on diuresis in water immersion. The water was kept at close to 34.5 C and the subjects remained in the water for 4 hr after sitting for 2 hr. Na and K levels in the serum and urine were analyzed, as were osmolality, red blood cell count, renin activity, total protein, albumin amounts, hematocrit, and hemoglobin. Plasma volume was monitored from samples drawn at specified intervals during immersion. The plasma volume increased significantly 30 min after immersion, but no PVP was observed. The dehydration induced elevated serum osmotic concentrations. It is concluded that the hydration condition before immersion and the volume of fluid intake during immersion affects the hemodilution during immersion.

  19. Immersion diuresis without expected suppression of vasopressin

    NASA Technical Reports Server (NTRS)

    Keil, L. C.; Silver, J. E.; Wong, N.; Spaul, W. A.; Greenleaf, J. E.; Kravik, S. E.

    1984-01-01

    There is a shift of blood from the lower parts of the body to the thoracic circulation during bed rest, water immersion, and presumably during weightlessness. On earth, this central fluid shift is associated with a profound diuresis. However, the mechanism involved is not yet well understood. The present investigation is concerned with measurements regarding the plasma vasopressin, fluid, electrolyte, and plasma renin activity (PRA) responses in subjects with normal preimmersion plasma vasopressin (PVP) concentration. In the conducted experiments, PRA was suppressed significantly at 30 min of immersion and had declined by 74 percent by the end of the experiment. On the basis of previously obtained results, it appears that sodium excretion during immersion may be independent of aldosterone action. Experimental results indicate that PVP is not suppressed by water immersion in normally hydrated subjects and that other factors may be responsible for the diuresis.

  20. Macrocellular vitreous carbon with the improved mechanical strength

    NASA Astrophysics Data System (ADS)

    Smorygo, Oleg; Marukovich, Alexander; Mikutski, Vitali; Pramono, Andika

    2015-12-01

    Vitreous carbons with regular macrocellular structure, open interconnected porosity, high specific strength and hydraulic permeability were synthesized by infiltration of the epoxy resin into the sacrificial template made from the carbamide granules. Polyvinylpyrrolidone (PVP) solution in ethanol was used as the template binder. When the resin setting and the template extraction had been performed, the resultant porous material was pyrolysed in the nitrogen flow. Depending on PVP concentration in the template binder, final vitreous carbons had the following properties: bulk density at 0.17-0.22 g/cm3; porosity at 85.7%-89.0%; window size at 447-735 µm; Darcian permeability coefficient at (0.64-9.5)×10-9m2; non-Darcian permeability coefficient at (0.53-3.36)×10-4 m. High specific strength of above 8×103 Pa/(kg·m-3) was attained.

  1. Blinking suppression of CdTe quantum dots on epitaxial graphene and the analysis with Marcus electron transfer

    SciTech Connect

    Hirose, Takuya; Tamai, Naoto; Kutsuma, Yasunori; Kurita, Atsusi; Kaneko, Tadaaki

    2014-08-25

    We have prepared epitaxial graphene by a Si sublimation method from 4H-SiC. Single-particle spectroscopy of CdTe quantum dots (QDs) on epitaxial graphene covered with polyvinylpyrrolidone (PVP) or polyethylene glycol (PEG) showed the suppression of luminescence blinking and ∼10 times decreased luminescence intensity as compared with those on a glass. The electronic coupling constant, H{sub 01}, between CdTe QDs and graphene was calculated to be (3.3 ± 0.4) × 10{sup 2 }cm{sup −1} in PVP and (3.7 ± 0.8) × 10{sup 2 }cm{sup −1} in PEG based on Marcus theory of electron transfer and Tang-Marcus model of blinking with statistical distribution.

  2. Producing Zirconium Diboride Components with Complex, Near-Net Shape Geometries by Aqueous Room-Temperature Injection Molding

    NASA Technical Reports Server (NTRS)

    Wiesner, Valerie L.; Youngblood, Jeffrey; Trice, Rodney

    2014-01-01

    Room-temperature injection molding is proposed as a novel, low-cost and more energy efficient manufacturing process capable of forming complex-shaped zirconium diboride (ZrB2) parts. This innovative processing method utilized aqueous suspensions with high powder loading and a minimal amount (5 vol.) of water-soluble polyvinylpyrrolidone (PVP), which was used as a viscosity modifier. Rheological characterization was performed to evaluate the room-temperature flow properties of ZrB2-PVP suspensions. ZrB2 specimens were fabricated with high green body strength and were machinable prior to binder removal despite their low polymer content. After binder burnout and pressureless sintering, the bulk density and microstructure of specimens were characterized using Archimedes technique and scanning electron microscopy. X-Ray Diffraction was used to determine the phase compositions present in sintered specimens. Ultimate strength of sintered specimens will be determined using ASTM C1323-10 compressive C-ring test.

  3. Surface modification of polymeric materials and its effect on blood compatibility

    SciTech Connect

    Wrobleski, D.A.; Cash, D.L.; Archuleta, T.; Barthell, B.L.; Kossowsky, R.; London, J.E.; Lehnert, B.E.; Duchane, D.V.

    1987-01-01

    The surfaces of commercially available polymeric materials have been modified through the chemical infusion process and physical vapor deposition. The surfaces of poly(methylmethacrylate) (PMMA) have been modified through a chemical infusion process by treatment of the sample with a solution containing varying amounts of titanium(IV)isopropoxide and polyvinylpyrrolidone (PVP). The surfaces of silicone rubber samples have been coated with a thin coating of titanium dioxide with an ion beam sputtering technique. The treated samples were characterized by scanning electron microscopy, optical microscopy, and neutron activation analysis. The infused samples were evaluated for blood compatibility using two biological assays: an adherence assay in which the adherence of human polymorphonuclear leukocytes to the samples was determined, and a hemolysis assay using rat blood erythrocytes to determine the hemolytic activity of the samples. Based on the results of these assays, the PMMA samples treated with PVP alone resulted in an improvement in reactivity with the blood cells. 16 refs., 4 figs.

  4. Effect of different surfactants and thicknesses on electrodeposited films of bismuth telluride and its thermoelectric performance

    NASA Astrophysics Data System (ADS)

    Kulsi, Chiranjit; Mitra, Mousumi; Kargupta, Kajari; Ganguly, Saibal; Banerjee, Dipali; Goswami, Shyamaprosad

    2015-10-01

    Thin films of bismuth telluride using various surfactants such as sodium dodecyl sulfate (SDS) and polyvinylpyrrolidone (PVP) have been electrochemically deposited. The influence of different surfactants on crystal orientation and morphology was investigated and correlated with the thermoelectric performance of the electrodeposited films. Since thickness affects the thermoelectric performance compared to the surfactant, thickness- dependent thermoelectric performance has also been investigated. The carrier mobilities of the films obtained are significantly enhanced due to improved surface morphology using different surfactants. Between the two surfactants, films with SDS exhibited the higher value of thermoelectric power, power factor, and figure of merit, which is due to the effect of micelle formation. The XRD pattern of all the films, which are electrodeposited without surfactant or using SDS and PVP, showed preferred crystal orientation along the (018) direction. The roles of organic molecules in the development of nanoparticles with improved thermoelectric properties have been investigated.

  5. The enhanced SERS effect of Ag/ZnO nanoparticles through surface hydrophobic modification

    NASA Astrophysics Data System (ADS)

    Li, Zhenjiang; Zhu, Kaixing; Zhao, Qian; Meng, Alan

    2016-07-01

    Ag/ZnO nanocomposites modified by a mixture of stearic acid (SA) and polyvinylpyrrolidone (PVP) were obtained using a heating reflux method. Fourier transform infrared spectroscopy (FT-IR) suggests that organic SA/PVP was bonded onto the surface of Ag/ZnO nanocrystals, converting the wettability property of the nanostructures from hydrophilic to hydrophobic. The modified Ag/ZnO nanostructures were confirmed as effective Raman substrates, with a 3-fold signal enhancement compared to the ordinary hydrophilic Ag/ZnO substrate for detecting Rh B molecules due to the hydrophobic condensation effect. It is expected that the modified Ag/ZnO nanoparticles have potential for SERS-based rapid detection of molecules.

  6. Thymocyte plasma membrane: the location of specific glucocorticoid binding sites

    SciTech Connect

    Sergeev, P.V.; Kalinin, G.V.; Dukhanin, A.S.

    1987-01-01

    In modern molecular endocrinology it is now possible to determine the localization of receptors for biologically active substances with the aid of ligands, with high affinity for the receptor, immobilized on polymers. The purpose of this paper is to study the ability of hydrocortisone (HC), immobilized on polyvinylpyrrolidone (PVP-HC), to reduce binding of tritium-HC by thymocytes of adrenalectomized rats. It is determined that specific binding sites for HC on rat thymocytes are also accessible for PVP-HC, which, due to the fact that this immobilized version of HC does not penetrate into the cell, leads to the conclusion that the binding sites for HC itself are located in the plasma membrane.

  7. Rapid Imaging of Latent Fingerprints Using Biocompatible Fluorescent Silica Nanoparticles.

    PubMed

    Kim, Young-Jae; Jung, Hak-Sung; Lim, Joohyun; Ryu, Seung-Jin; Lee, Jin-Kyu

    2016-08-16

    Fluorescent silica nanoparticles (FSNPs) are synthesized through the Stöber method by incorporating silane-modified organic dye molecules. The modified fluorescent organic dye molecule is able to be prepared by allylation and hydrosilylation reactions. The optical properties of as-prepared FSNPs are shown the similar optical properties of PR254A (allylated Pigment Red 254) and have outstanding photostability. The polyvinylpyrrolidone (PVP) is introduced onto the surface of FSNP to enhance the binding affinity of PVP-coated FSNP for latent fingerprints (LFPs) detection. The simple preparation and easy control of surface properties of FSNPs show potential as a fluorescent labeling material for enhanced latent fingerprint detection on hydrophilic and hydrophobic substrates in forensic science for individual identification. PMID:27452188

  8. High sensitivity and high resolution element 3D analysis by a combined SIMS-SPM instrument.

    PubMed

    Fleming, Yves; Wirtz, Tom

    2015-01-01

    Using the recently developed SIMS-SPM prototype, secondary ion mass spectrometry (SIMS) data was combined with topographical data from the scanning probe microscopy (SPM) module for five test structures in order to obtain accurate chemical 3D maps: a polystyrene/polyvinylpyrrolidone (PS/PVP) polymer blend, a nickel-based super-alloy, a titanium carbonitride-based cermet, a reticle test structure and Mg(OH)2 nanoclusters incorporated inside a polymer matrix. The examples illustrate the potential of this combined approach to track and eliminate artefacts related to inhomogeneities of the sputter rates (caused by samples containing various materials, different phases or having a non-flat surface) and inhomogeneities of the secondary ion extraction efficiencies due to local field distortions (caused by topography with high aspect ratios). In this respect, this paper presents the measured relative sputter rates between PVP and PS as well as in between the different phases of the TiCN cermet. PMID:26171285

  9. Light-induced characteristic variations in organic thin-film transistors with a poly(vinylphenol-co-methyl methacrylate)/titanium-dioxide nanocomposite gate dielectric

    NASA Astrophysics Data System (ADS)

    Kim, Dongwook; Shin, Hyunji; Park, Sangcheol; Lee, Dokyoung; Choi, Jong Sun; Baang, Sungkeun; Ham, Youngjin; Park, Jaehoon; Piao, Shang Hao; Choi, Hyoung Jin

    2015-11-01

    We investigated the effect of light exposure on the electrical characteristics of organic thinfilm transistors (OTFTs) fabricated with a cross-linked poly(vinylphenol-co-methyl methacrylate) (PVP-co-PMMA)/titanium-dioxide (TiO2) nanocomposite gate dielectric. When illuminated, the off-state drain current increased significantly in the OTFTs containing the TiO2 nanocomposite gate dielectric, but changed negligibly in those containing the pristine PVP-co-PMMA gate dielectric. On the other hand, the dependence of the on-state drain current on the photon energy was similar in both cases. These results can be explained in terms of photogenerated charge carriers in the organic semiconductor and the TiO2 nanoparticles.

  10. Formulation and Characterization of CuIn1-xGaxSe2 Ink for Gravure Offset Printing

    NASA Astrophysics Data System (ADS)

    Kim, Inyoung; Han, Hyun-Suk; Kwak, Sun-Woo; Yu, Jong-Su; Kim, Bongmin; Jang, Yunseok; Lee, Taik-Min

    2013-05-01

    CuIn1-xGaxSe2 (CIGS) paste for gravure offset printing was formulated by changing the amount of additives to determine the critical factor for gravure offset printing quality. With the addition of poly(vinyl pyrrolidone) (PVP), the viscosity and yield stress of CIGS ink decreased and shear thinning behavior disappeared. However, PVP effectively enhanced ink cohesion and elastic modulus, which critically affected the printability of the CIGS paste. Intense pulsed light (IPL) treatment in air made the microstructure of CIGS film denser without a phase change or oxidation. The gravure offset printing technique and IPL treatment were considered a good combination for a continuous and fast CIGS film growth process.

  11. Resistive switching memory devices based on electrical conductance tuning in poly(4-vinyl phenol)-oxadiazole composites.

    PubMed

    Sun, Yanmei; Miao, Fengjuan; Li, Rui; Wen, Dianzhong

    2015-11-28

    Nonvolatile memory devices, based on electrical conductance tuning in thin films of poly(4-vinyl phenol) (PVP) and 2-(4-tert-butylphenyl)-5-(4-biphenylyl)-1,3,4-oxadiazole (PBD) composites, are fabricated. The current-voltage characteristics of the fabricated devices show different electrical conductance behaviors, such as the write-once read-many-times (WORM) memory effect, the rewritable flash memory effect and insulator behavior, which depend on the content of PBD in the PVP + PBD composites. The OFF and ON states of the WORM and rewritable flash memory devices are stable under a constant voltage stress or a continuous pulse voltage stress at a read voltage. The memory mechanism is deduced from the modeling of the nature of currents in both states in the devices. PMID:26490192

  12. Composite silica coated gold nanosphere and quantum dots nanoparticles for X-ray CT and fluorescence bimodal imaging.

    PubMed

    Song, Ji-Tao; Yang, Xiao-Quan; Zhang, Xiao-Shuai; Yan, Dong-Mei; Yao, Ming-Hao; Qin, Meng-Yao; Zhao, Yuan-Di

    2015-07-01

    In this study, silica coated Au nanospheres (Au@SiO2) were prepared by a reverse microemulsion method; subsequently, a layer of fluorescent quantum dots (QDs) were adsorbed onto it and then it was coated with silica again. After modifying with PVP, the composite silica coated gold nanosphere and quantum dots nanoparticle (Au@SiO2-QDs/SiO2-PVP) was obtained. This composite structure contained Au and QDs, and it could be used for contrast-enhanced X-ray CT imaging and fluorescence imaging. Characterization showed that the composite nanoparticle had good dispersity, a high fluorescence intensity and a good effect of X-ray absorption, and it was suitable for using as a bimodal imaging probe. PMID:26008798

  13. Hysteresis free carbon nanotube thin film transistors comprising hydrophobic dielectrics

    NASA Astrophysics Data System (ADS)

    Lefebvre, J.; Ding, J.; Li, Z.; Cheng, F.; Du, N.; Malenfant, P. R. L.

    2015-12-01

    We present two examples of carbon nanotube network thin film transistors with strongly hydrophobic dielectrics comprising either Teflon-AF or a poly(vinylphenol)/poly(methyl silsesquioxane) (PVP/pMSSQ) blend. In the absence of encapsulation, bottom gated transistors in air ambient show no hysteresis between forward and reverse gate sweep direction. Device threshold gate voltage and On-current present excellent time dependent stability even under dielectric stress. Furthermore, threshold gate voltage for hole conduction is negative upon device encapsulation with PVP/pMSSQ enabling much improved current On/Off ratio at 0 V. This work addresses two major challenges impeding solution based fabrication of relevant thin film transistors with printable single-walled carbon nanotube channels.

  14. Tunable biphasic drug release from ethyl cellulose nanofibers fabricated using a modified coaxial electrospinning process

    PubMed Central

    2014-01-01

    This manuscript reports a new type of drug-loaded core-shell nanofibers that provide tunable biphasic release of quercetin. The nanofibers were fabricated using a modified coaxial electrospinning process, in which a polyvinyl chloride (PVC)-coated concentric spinneret was employed. Poly (vinyl pyrrolidone) (PVP) and ethyl cellulose (EC) were used as the polymer matrices to form the shell and core parts of the nanofibers, respectively. Scanning and transmission electron microscopy demonstrated that the nanofibers had linear morphologies and core-shell structures. The quercetin was found to be present in the nanofibers in the amorphous physical status, on the basis of X-ray diffraction results. In vitro release profiles showed that the PVP shell very rapidly freed its drug cargo into the solution, while the EC core provided the succedent sustained release. Variation of the drug loading permitted the release profiles to be tuned. PMID:24940180

  15. Radiation synthesis and characterization of stimuli-sensitive chitosan-polyvinyl pyrrolidone hydrogels

    NASA Astrophysics Data System (ADS)

    Dergunov, Sergey A.; Nam, Irina K.; Mun, Grigoriy A.; Nurkeeva, Zauresh S.; Shaikhutdinov, Erengaip M.

    2005-04-01

    Novel cationic hydrogels were synthesized by γ-irradiation copolymerization of chitosan and polyvinyl pyrrolidone (PVP). The synthesis regularities and the swelling behaviour of hydrogels have been studied. It was shown that increasing of PVP concentration in feed composition also as radiation dose accompanied of increase of yield of gel fraction and decrease of swelling degree. At dose more than 3.5 kGy increasing of swelling degree and decreasing of gel fraction yield have been observed. It was shown that the hydrogels exhibit pH-sensitive behaviour in aqueous solution. In solutions of sodium dodecyl sulfate (SDS) the hydrogels are collapsed due to complexation, however, at concentration of SDS solution equal to critical micelle concentration the gels contracted and then swollen again.

  16. Effect of the substrate-binder interactions on the mechanical properties of compacts.

    PubMed

    Remon, J P; Kiekens, F; Zelkó, R

    1998-11-01

    The effect of the substrate-binder interfacial interaction in granules, made of PVP and glass ballotini as model substrates, on the mechanical properties of rectangular compacts consisting of these granules was investigated by use of the four-point beam bending technique. The mechanical properties of the prepared compacts were correlated with the physico-chemical characteristics--contact angle, surface tension and binder concentration--of the granulation liquid. The mechanical strength and Young's modulus of the specimens both reached a maximum value when the binder concentration in the granulation liquid was increased to 20% (w/v) for all granulation liquid volumes used. Above a 20% PVP concentration, the increasing granulation liquid contact angle hindered the binder spreading, creating weak regions in the compact and decreasing its mechanical strength. PMID:9987196

  17. A 980nm driven photothermal ablation of virulent and antibiotic resistant Gram-positive and Gram-negative bacteria strains using Prussian blue nanoparticles.

    PubMed

    Maaoui, Houcem; Jijie, Roxana; Pan, Guo-Hui; Drider, Djamel; Caly, Delphine; Bouckaert, Julie; Dumitrascu, Nicoleta; Chtourou, Radouane; Szunerits, Sabine; Boukherroub, Rabah

    2016-10-15

    A 980nm laser-driven antimicrobial photothermal therapy using poly(vinylpyrrolidone) -coated Prussian Blue nanoparticles (PVP/PB NPs) is demonstrated. This approach allows an efficient eradication of a virulent strain of Gram-negative Escherichia coli (E. coli) associated with urinary tract infection as well as for the ablation of antibiotic resistant pathogens such as methicillin resistant Staphylococcus aureus (MRSA) and extended spectrum β-lactamase (ESBL) E. coli. Interestingly the 980nm irradiation exhibits minimal effect on mammalian cells up to a PVP/PB NPs concentration of 50μgmL(-1), while at this concentration bacteria are completely eradicated. This feature is certainly very promising for the selective targeting of bacteria over mammalian cells. PMID:27405072

  18. Water-soluble polymer exfoliated graphene: as catalyst support and sensor.

    PubMed

    Wang, Haibo; Xia, Baoyu; Yan, Ya; Li, Nan; Wang, Jing-Yuan; Wang, Xin

    2013-05-01

    In this paper, we obtained various water-soluble polymer functionalized graphene in dimethyl sulfoxide under ultrasonication. The atomic force microscope analysis and control experiment shows the water-soluble polymer is the crucial part to help solvent molecules separate interlayer. Such polymer/graphene exhibits high conductivity and tunable surface property, as confirmed by the selected area electron diffraction and Raman and electrochemical impedance spectroscopy. As a result, a catalyst based on polyvinyl pyrrolidone (PVP)/graphene shows better methanol oxidation performance than that based on PVP/reduced graphene oxide. By changing to another polymer, poly(4-vinylpyridine)/graphene shows a stable and reversible response to pH, and demonstrates its potential for sensor application. PMID:23574310

  19. A rare but serious complication of GreenLight HPS photoselective vaporization of the prostate: Prostatic capsular perforation with bilateral thigh urinomas and osteitis pubis.

    PubMed

    Harriman, David; Mayson, Brian E; Leone, Ercole F

    2013-01-01

    The use of lasers to perform photoselective vaporization of the prostate (PVP) has been widely accepted as a safe and effective treatment for benign prostatic hyperplasia with very few reported complications. To date, most of the published data report outcomes for the 80-W potassium-titanyl-phosphate laser. A more potent laser, the 120-W GreenLight HPS, was introduced in 2006 and provides more efficient vaporization of prostatic tissue and decreased operating times. Despite these benefits, the increased energy applied to the prostate evokes concerns of potential serious complications, including capsular perforation and injury to adjacent structures. A more powerful laser system, the 180-W GreenLight XPS laser (American Medical Systems, Minnetonka, MN) has recently become available. We report a rare but serious complication of GreenLight HPS PVP resulting in prostatic capsular perforation with urinary extravasation, presenting with bilateral thigh urinomas and osteitis pubis. PMID:23671496

  20. Advances in the clinical research of the minimally invasive treatment for the posterior edge of vertebral-body defects by spinal metastases

    PubMed Central

    LIU, XUEFENG; YANG, ZUOZHANG; XIE, LIN; YUAN, ZONGQIN; REN, MINGYAN; HAN, LEI

    2015-01-01

    Spinal metastasis is one of the commonly observed complications in the advanced stages of cancer patients, and is a serious threat to human life and health. Malignant tumor invasion usually leads to defects in the posterior margins of the vertebral body, which caused significant cancer pains to patients and increased the risk of surgery. Currently, minimally invasive treatments of vertebral defects caused by spinal metastases include percutaneous vertebroplasty (PVP) combined with radiofrequency ablation and PVP combined with 125I seed implantation. These minimally invasive techniques have particular superiority to control pain in patients with spinal metastases, improve nerve function, reduce the incidence of fractures and surgical risk, and improve the quality of life. The present study reviewed the progress in clinical research on vertebral defects caused by spinal metastases, and the mechanisms and minimally invasive treatment. PMID:26405535

  1. Synthesis, Characterization, and X-ray Attenuation Properties of Ultrasmall BiOI Nanoparticles: Toward Renal Clearable Particulate CT Contrast Agents

    PubMed Central

    2015-01-01

    A unique decelerated hydrolytic procedure is developed and reported here for the preparation of ultrasmall nanoparticles (NPs) of PVP-coated BiOI with a narrow size distribution, i.e., 2.8 ± 0.5 nm. The crystal structure of this compound is determined by X-ray powder diffraction using the bulk materials. The stability, cytotoxicity, and potential use of the PVP-coated ultrasmall BiOI NPs as a CT contrast agent are investigated. Because of the combined X-ray attenuation effect of bismuth and iodine, such NPs exhibit a CT value that is among the best of those of the inorganic nanoparticle-based CT contrast agents reported in the literature. PMID:25283335

  2. Fabrication of multilayer passive electric components using inkjet printing and low temperature laser processing on polymer

    NASA Astrophysics Data System (ADS)

    Ko, Seung Hwan; Chung, Jaewon; Pan, Heng; Grigoropoulos, Costas P.; Poulikakos, Dimos

    2006-02-01

    The low temperature fabrication of passive electrical components (conductor, capacitor) on the flexible polymer substrate is presented in this paper. A drop-on-demand (DOD) ink-jetting system was used to print gold nano-particles suspended in Alpha-Terpineol solvent and PVP in PGMEA solvent to fabricate passive electrical components on flexible polymer substrate. Short pulsed laser ablation enabled finer electrical components to overcome limitation of inkjet process. Continuous Argon ion laser was irradiated locally to evaporate carrier solvent as well as to sinter gold nano-particles. In addition, a self alignment technique for PVP layer was demonstrated taking advantage of the deliberate modification of surface wetting characteristics. Finally, a new selective ablation of multilayered gold nanoparticle film was demonstrated using the ablation threshold difference for sintered and non sintered gold nanoparticles.

  3. Stable luminescence from individual carbon nanotubes in acidic, basic, and biological environments.

    PubMed

    Duque, Juan G; Cognet, Laurent; Parra-Vasquez, A Nicholas G; Nicholas, Nolan; Schmidt, Howard K; Pasquali, Matteo

    2008-02-27

    Aqueous surfactant suspensions of single walled carbon nanotubes (SWNTs) are very sensitive to environmental conditions. For example, the photoluminescence of semiconducting SWNTs varies significantly with concentration, pH, or salinity. In most cases, these factors restrict the range of applicability of SWNT suspensions. Here, we report a simple strategy to obtain stable and highly luminescent individualized SWNTs at pH values ranging from 1 to 11, as well as in highly saline buffers. This strategy relies on combining SWNTs previously suspended in sodium dodecylbenzene sulfonate (SDBS) with biocompatible poly(vinyl pyrrolidone) (PVP), which can be polymerized in situ to entrap the SWNT-SDBS micelles. We present a model that accounts for the photoluminescence stability of these suspensions based on PVP morphological changes at different pH values. Moreover, we demonstrate the effectiveness of these highly stable suspensions by imaging individual luminescent SWNTs on the surface of live human embryonic kidney cells (HEK cells). PMID:18237169

  4. Self-constructed tree-shape high thermal conductivity nanosilver networks in epoxy.

    PubMed

    Pashayi, Kamyar; Fard, Hafez Raeisi; Lai, Fengyuan; Iruvanti, Sushumna; Plawsky, Joel; Borca-Tasciuc, Theodorian

    2014-04-21

    We report the formation of high aspect ratio nanoscale tree-shape silver networks in epoxy, at low temperatures (<150 °C) and atmospheric pressures, that are correlated to a ∼200 fold enhancement of thermal conductivity (κ) of the nanocomposite compared to the polymer matrix. The networks form through a three-step process comprising of self-assembly by diffusion limited aggregation of polyvinylpyrrolidone (PVP) coated nanoparticles, removal of PVP coating from the surface, and sintering of silver nanoparticles in high aspect ratio networked structures. Controlling self-assembly and sintering by carefully designed multistep temperature and time processing leads to κ of our silver nanocomposites that are up to 300% of the present state of the art polymer nanocomposites at similar volume fractions. Our investigation of the κ enhancements enabled by tree-shaped network nanocomposites provides a basis for the development of new polymer nanocomposites for thermal transport and storage applications. PMID:24615536

  5. Laser-induced periodic surface structuring of biopolymers

    NASA Astrophysics Data System (ADS)

    Pérez, Susana; Rebollar, Esther; Oujja, Mohamed; Martín, Margarita; Castillejo, Marta

    2013-03-01

    We report here on a systematic study about the formation of laser-induced periodic surface structures (LIPSS) on biopolymers. Self-standing films of the biopolymers chitosan, starch and the blend of chitosan with the synthetic polymer poly (vinyl pyrrolidone), PVP, were irradiated in air with linearly polarized laser beams at 193, 213 and 266 nm, with pulse durations in the range of 6-17 ns. The laser-induced periodic surface structures were topographically characterized by atomic force microscopy and the chemical modifications induced by laser irradiation were inspected via Raman spectroscopy. Formation of LIPSS parallel to the laser polarization direction, with periods similar to the laser wavelength, was observed at efficiently absorbed wavelengths in the case of the amorphous biopolymer chitosan and its blend with PVP, while formation of LIPSS is prevented in the crystalline starch biopolymer.

  6. Sum Frequency Generation Studies of Hydrogenation Reactions on Platinum Nanoparticles

    SciTech Connect

    Krier, James M.

    2013-08-31

    Sum Frequency Generation (SFG) vibrational spectroscopy is used to characterize intermediate species of hydrogenation reactions on the surface of platinum nanoparticle catalysts. In contrast to other spectroscopy techniques which operate in ultra-high vacuum or probe surface species after reaction, SFG collects information under normal conditions as the reaction is taking place. Several systems have been studied previously using SFG on single crystals, notably alkene hydrogenation on Pt(111). In this thesis, many aspects of SFG experiments on colloidal nanoparticles are explored for the first time. To address spectral interference by the capping agent (PVP), three procedures are proposed: UV cleaning, H2 induced disordering and calcination (core-shell nanoparticles). UV cleaning and calcination physically destroy organic capping while disordering reduces SFG signal through a reversible structural change by PVP.

  7. Gold nanostars reshaping and plasmon tuning mechanism

    NASA Astrophysics Data System (ADS)

    Kedia, Abhitosh; Kumar, P. Senthil

    2013-02-01

    Au nanostars are multi-branched nanoparticles with sharp tips which display enhanced plasmonic applications in SERS and nanophotonics. It has already been well documented that polyvinylpyrrolidone (PVP) dispersed in DMF solvent medium act as a unique candidate for realization of this 3-D complex branched metal nanostructures even under normal conditions. Interestingly, controlled addition of propanol to DMF brings about significant changes in the morphology of these gold nanostars visualized through gradual blue shifting of the localized surface plasmon resonance (LSPR) from 920 to 600 nm. Modified interaction between DMF-PVP arising due to introduction of alcohol results in fine tuning of LSPR correlated with corresponding aesthetic changes as clearly evidenced from TEM images. Thus, our ability in synthesizing anisotropic metal nanoparticles with wavelength tunable LSPRs through a simple yet elegant chemical solution synthesis procedure opens up a gamut of new applications in both linear and nonlinear optical spectroscopy.

  8. A simple one-pot strategy to platinum-palladium@palladium core-shell nanostructures with high electrocatalytic activity

    NASA Astrophysics Data System (ADS)

    Lv, Jing-Jing; Zheng, Jie-Ning; Wang, Ying-Ying; Wang, Ai-Jun; Chen, Li-Li; Feng, Jiu-Ju

    2014-11-01

    Well-defined platinum-palladium@palladium core-shell nanospheres (PtPd@Pd NSs) are synthesized by a facile one-pot solution approach using N-methylimidazole and poly(vinyl pyrrolidone) (PVP) as directing and capping agents, respectively, without using any seed, template, or organic solvent. The coexistence of the precursors, N-methylimidazole, PVP, and reaction temperature has great effects on the final morphology. Thus-prepared nanocomposites display an improved electrocatalytic activity for oxygen reduction reaction (ORR) in acidic media, methanol and ethylene glycol oxidation reaction in alkaline media, compared with Pt nanoparticles, Pd nanoparticles, commercial Pt black and Pd black catalysts. This method may direct a general orientation for shape control synthesis of functional bimetallic nanocrystals as promising electrocatalysts in direct alcohol fuel cells (DAFCs).

  9. Minimalism in radiation synthesis of biomedical functional nanogels.

    PubMed

    Dispenza, Clelia; Sabatino, Maria Antonietta; Grimaldi, Natascia; Bulone, Donatella; Bondì, Maria Luisa; Casaletto, Maria Pia; Rigogliuso, Salvatrice; Adamo, Giorgia; Ghersi, Giulio

    2012-06-11

    A scalable, single-step, synthetic approach for the manufacture of biocompatible, functionalized micro- and nanogels is presented. In particular, poly(N-vinyl pyrrolidone)-grafted-(aminopropyl)methacrylamide microgels and nanogels were generated through e-beam irradiation of PVP aqueous solutions in the presence of a primary amino-group-carrying monomer. Particles with different hydrodynamic diameters and surface charge densities were obtained at the variance of the irradiation conditions. Chemical structure was investigated by different spectroscopic techniques. Fluorescent variants were generated through fluorescein isothiocyanate attachment to the primary amino groups grafted to PVP, to both quantify the available functional groups for bioconjugation and follow nanogels localization in cell cultures. Finally, a model protein, bovine serum albumin, was conjugated to the nanogels to demonstrate the attachment of biologically relevant molecules for targeting purposes in drug delivery. The described approach provides a novel strategy to fabricate biohybrid nanogels with a very promising potential in nanomedicine. PMID:22571354

  10. Large-scale synthesis well-dispersed ZnS microspheres and their photoluminescence, photocatalysis properties

    SciTech Connect

    Wang Xinjun Wan Fuquan; Han Kun; Chai Chunxia; Jiang Kai

    2008-12-15

    Large-scale and well-dispersed ZnS microspheres were prepared by a simple hydrothermal method using ZnSO{sub 4}{center_dot}7H{sub 2}O and SC(NH{sub 2}){sub 2} as main original reactant and poly(vinyl pyrrolidone) (PVP)(Mr {approx} 10,000) as the surfactant. The products were characterized by X-Ray diffraction, scanning electron microscopy and transmission electron microscopy. The growth process involves a special oriented aggregation of PVP stabilized ZnS nanoparticles into microspheres of 1.5 {approx} 2.0 {mu}m in sizes. The photocatalytic activity of as-prepared ZnS microsphere was evaluated by using methylene blue (MB) as a model organic compound. The optical properties of the products were also examined by means of photoluminescence (PL) spectroscopy.

  11. In Vitro and In Vivo Evaluation of Oxatomide β-Cyclodextrin Inclusion Complex

    PubMed Central

    Hashem, Fahima M.; Mostafa, Mohamed; Shaker, Mahmoud; Nasr, Mohamed

    2013-01-01

    The objective of this study was to evaluate the influence of oxatomide β-cyclodextrin inclusion complex on the physicochemical properties and bioavailability of the drug. Oxatomide β-cyclodextrin solid complex was prepared with equimolar ratio of both oxatomide and β-cyclodextrin in presence or absence of water soluble polymers using different techniques. The coevaporated complex prepared in presence of PVP-K15 showed a prompt drug release and significantly increased % dissolution efficiency (P < 0.05) compared to the pure oxatomide. Moreover, the results of bioavailability evaluation of this complex in rabbits compared to commercial drug product indicated a 73.15% increase in the oral bioavailability of oxatomide. In conclusion, inclusion complex of oxatomide with β-cyclodextrin prepared by coevaporation in presence of PVP-K15 not only results in an enhancement of the oxatomide dissolution rate but also improves the bioavailability of oxatomide. PMID:26555988

  12. Protein expression profiles of intestinal epithelial co-cultures: effect of functionalised carbon nanotube exposure

    PubMed Central

    Lai, Xianyin; Blazer-Yost, Bonnie L.; Clack, James W.; Fears, Sharry L.; Mitra, Somenath; Ntim, Susana Addo; Ringham, Heather N.

    2013-01-01

    To assess the biological effects of low level, water dispersible, functionalised carbon nanotube (f-CNT) exposure in an in vitro model simulating the digestive tract, cellular protein expression was quantified and compared using label-free quantitative mass spectrometry (LFQMS). Co-cultured cells were exposed to well-characterised SWCNT-COOH, MWCNT-COOH, and MWCNT-PVP. The relative expression of 2,282 unique proteins was compared across the dose groups. 428 proteins were found to be differentially expressed. At the high dose, the extent of differential protein expression was CNT-specific and directly related to CNT colloidal stability. Cells responded to low level MWCNT-PVP exposure with three-fold greater differential expression. Bioinformatic analysis indicated significant and f-CNT-specific effects on relevant molecular and cellular functions and canonical pathways, with little overlap across f-CNT type and in the absence of overt toxicity. PMID:24228069

  13. Highly Porous Regenerated Cellulose Fiber Mats via the Co-Forcespinning of Cellulose Acetate for Separator Applications

    NASA Astrophysics Data System (ADS)

    Castillo, Alejandro; Mao, Yuanbing

    2015-03-01

    Improvements in battery technology are necessary for the transition away from a fossil fuel based economy. An important bottle-neck in battery efficiency is the quality of the separator, which separates the cathode and anode to prevent a short-circuit while still allowing the ions in solution to flow as close to unabated as possible. In this work solutions of cellulose acetate, polyvinyldiflourine (pvdf), and polyvinylpyrrolidone (pvp) dissolved in a 2:1 v/v acetone/dimethylacetamide solvent mixture were Forcespun to create nonwoven fiber mats of nanoscale diameter. These mats were then soaked in a NaOH solution so as to both strip the pvp from the fiber as well as regenerate cellulose from its acetate derivative for the purpose of creating high surface area, nanoporous, hydrophilic, and ioniclly conductive cellulose/pvdf nonwoven mats for the purposes of testing their suitability as battery separators

  14. Onychomycosis treated with a dilute povidone–iodine/dimethyl sulfoxide preparation

    PubMed Central

    Capriotti, Kara; Capriotti, Joseph A

    2015-01-01

    Background Povidone–iodine (PVP-I) 10% aqueous solution is a well-known, nontoxic, commonly used topical antiseptic with no reported incidence of fungal resistance. We have been using a low-dose formulation of 1% PVP-I (w/w) in a solution containing dimethyl sulfoxide (DMSO) in our clinical practice for a variety of indications. Presented here is our clinical experience with this novel formulation in a severe case of onychomycosis that was resistant to any other treatment. Findings A 49-year-old woman who had been suffering from severe onychomycosis for years presented after failing to find any remedy including over the counter (OTC), topical, and systemic oral prescribed therapies. Conclusion The topical povidone–iodine/DMSO system was very effective in this case at alleviating the signs and symptoms of onychomycosis. This novel combination warrants further investigation in randomized, controlled trials to further elucidate its clinical utility. PMID:26491374

  15. Tracing tree nut allergens in chocolate: A comparison of DNA extraction protocols.

    PubMed

    Costa, Joana; Melo, Vítor S; Santos, Cristina G; Oliveira, M Beatriz P P; Mafra, Isabel

    2015-11-15

    The present work aimed at comparing different DNA extraction methods, from chocolate matrices, for the effective application in molecular techniques to detect tree nut allergens. For this study, DNA from almond or hazelnut model chocolates was extracted using seven selected protocols: the in-house methods of CTAB-PVP (cetyltrimethylammonium bromide-polyvinylpyrrolidone), Wizard with and without RNase, Wizard-PVP with and without RNase, and the Wizard Magnetic and Nucleospin kits. The extracts were assessed for their suitability for amplification by qualitative PCR and real-time PCR. From the evaluated protocols, Nucleospin presented the best results for almond and hazelnut amplification, achieving a limit of detection of 0.005% (w/w) with high PCR efficiency, linearity and range of amplification. These results highlight the importance of the DNA extraction protocol in the case of food allergens from complex matrices, such as chocolate, in which sensitivity is a key parameter. PMID:25977052

  16. Synthesis of Mesoporous Transition-Metal Phosphates by Polymeric Micelle Assembly.

    PubMed

    Bastakoti, Bishnu Prasad; Li, Yunqi; Guragain, Sudhina; Pramanik, Malay; Alshehri, Saad M; Ahamad, Tansir; Liu, Zongwen; Yamauchi, Yusuke

    2016-05-23

    Mesoporous iron phosphate (FePO4 ) was synthesized through assembly of polymeric micelles made of asymmetric triblock co-polymer (polystyrene-b-poly-2-vinylpyridine-b-ethylene oxide; PS-PVP-PEO). The phosphoric acid solution stimulates the formation of micelles with core-shell-corona architecture. The negatively charged PO4 (3-) ions dissolved in the solution strongly interact with the positively charged PVP(+) units through an electrostatic attraction. Also, the presence of PO4 (3-) ions realizes a bridge between the micelle surface and the metal ions. The removal of polymeric template forms the robust framework of iron phosphate with 30 nm pore diameter and 15 nm wall thickness. Our method is applicable to other mesoporous metal phosphates by changing metal sources. The obtained materials were fully characterized by scanning electron microscope (SEM), transmission electron microscope (TEM), N2 adsorption-desorption, Raman spectroscope, and other techniques. PMID:27087399

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

    PubMed Central

    2009-01-01

    Background and purpose Commercial gentamicin-loaded bone cement beads (Septopal) constitute an effective delivery system for local antibiotic therapy. These beads are not available in all parts of the world, and are too expensive for frequent use in others. Thus, orthopedic surgeons worldwide make antibiotic-loaded beads themselves. However, these beads are usually not as effective as the commercial beads because of inadequate release kinetics. Our purpose was to develop a simple, cheap, and effective formulation to prepare gentamicin-loaded beads with release properties and antibacterial efficacy similar to the commercially ones. Methods Acrylic beads were prepared with variable monomer content: 100% (500 μL/g polymer), 75%, and 50% to increase gentamicin release through creation of a less dense polymer matrix. Using the optimal monomer content, different gel-forming polymeric fillers were added to enhance the permeation of fluids into the beads. Polyvinylpyrrolidone (PVP) 17 was selected as a suitable filler; its concentration was varied and the antibiotic release and antibacterial efficacy of these beads were compared with the corresponding properties of the commercial ones. Results Gentamicin release rate and the extent of release from beads prepared with 50% monomer increased when the PVP17 content was increased. Beads with 15 w/w% PVP17 released 87% of their antibiotic content. This is substantially more than the gentamicin release from Septopal beads (59%). Acrylic beads with 15 w/w% PVP17 reduced bacterial growth by up to 93%, which is similar to the antibacterial properties of the commercial ones. Interpretation A simple, cheap, and effective formulation and preparation process has been described for hand-made gentamicin-releasing acrylic beads, with better release kinetics and with antibacterial efficacy similar to that of the commercial ones. PMID:19916680

  18. Self-assembly of graphene onto electrospun polyamide 66 nanofibers as transparent conductive thin films

    NASA Astrophysics Data System (ADS)

    Huang, Yuan-Li; Baji, Avinash; Tien, Hsi-Wen; Yang, Ying-Kui; Yang, Shin-Yi; Ma, Chen-Chi M.; Liu, Hong-Yuan; Mai, Yiu-Wing; Wang, Nian-Hau

    2011-11-01

    A simple method was developed to assemble graphite oxide (GO) densely onto electrospun (ES) polyamide 66 (PA66) nanofibrous membranes, used as a guide for the deposition of graphene nanosheet (GNS) conductive networks for preparing transparent conductive thin film (TCF). The main advantage of this technique by comparison with previous methods is that graphene does not form a uniform coating, but a percolated conductive network, when guided by PA66 nanofiber templates. A low surface coverage of the transparent substrate by GNS resulted in high transmittance. Polyvinylpyrrolidone-stabilized GO (PVP-GO) was prepared as a modifier for improving the adsorption to the nanofibers. The resulting PVP-GO material could adsorb well on PA66 nanofibers due to stronger hydrogen bonds. Hence, a lower sufficient concentration of PVP-GO (0.050 wt%) solution was required than that for GO solution (0.100 wt%) to fabricate a complete conductive path through a possible enriched adsorption process. For TCF applications, a reduction step is essential because as-deposited GO is non-conductive. In this work, we reduced GO to GNS by a combination of chemical reduction and thermal annealing. The TCF optical transmittance also could be improved after thermal annealing at 350 °C above the PA66 melting point. Light scattering by PA66 nanofibers was found as the main cause of reduced transmittance. A fused film, obtained after electrospinning PA66 solution for 120 s, and immersing in 0.050 wt% PVP-GO solution, exhibits a surface resistance of 8.6 \\times 10^{3~}\\Omega /\\square , while maintaining 88% light transmittance.

  19. Fabrication of TiO2-strontium loaded CaSiO3/biopolymer coatings with enhanced biocompatibility and corrosion resistance by controlled release of minerals for improved orthopedic applications.

    PubMed

    Raj, V; Raj, R Mohan; Sasireka, A; Priya, P

    2016-07-01

    Titanium dioxide (TiO2) arrays were fabricated on Ti alloy by anodization method. Synthesis of CaSiO3 (CS) and various concentrations (1X-5X) of Sr(2+) substitutions in CS coatings on TiO2 substrate was achieved through an electrophoretic deposition technique. Fast release of mineral ions from implant surface produce over dosage effect and it is a potential hazardous factor for osteoblasts. So, in order to prevent the fast release of minerals, biopolymer coating was applied above the composite coatings. The coatings were characterized by FTIR, XRD, FE-SEM and EDX techniques. The mechanical, anticorrosion, antimicrobial properties and biocompatibility of the coatings were evaluated. Studies on the mechanical properties indicate that the addition of Sr(2+) and biopolymer increase the hardness strength of the coatings. The metal ion release from the coatings was studied by ICP-AES. The electrochemical properties of the coatings were studied in Ringer's solution, in which CS-3X/Chi-PVP coating on TiO2 exhibits good anticorrosion property and high resistivity against Escherichia coli and Staphylococcus aureus compared to CS-3X coating on TiO2. In vitro cell experiments indicate that osteoblasts show good adhesion and high growth rates for CS-3X/Chi-PVP coated TiO2 substrate, indicating that the surface cytocompatibility of CS-3X/Chi-PVP coated TiO2 substrate is significantly improved by the controlled release of mineral ions. In conclusion, the surface modification of TiO2/CS-3X/Chi-PVP coated titanium is a potential candidate for implant coating. PMID:27018944

  20. Preparation, characterization, and in vivo evaluation of valsartan porous matrices using emulsion solvent evaporation technique

    PubMed Central

    Babu, Govada Kishore; Babu, Puttagunta Srinivasa; Khagga, Mukkanti

    2016-01-01

    Introduction: Valsartan is a type II Biopharmaceutics Classification System (BCS) classified drug. The poor aqueous solubility restricts its use in developing sustained or controlled release systems for the treatment of chronic hypertensive conditions. The present investigation was conducted with an objective to formulate porous matrices (PMs) of valsartan in order to enhance aqueous solubility. Materials and Methods: Polyvinylpyrrolidone (PVP) K30 and poloxamer 407 were used as hydrophilic carriers; hexane was used as a pore-forming agent, ethanol was used as a solvent, and tween 20 was used as an emulgent. The prepared porous matrices were characterized and based on the maximum slope obtained from the Washburn method and other characterization results; the drug PVP K30 (1:1.5) was selected and further evaluated in vivo by the rat gut method. Results: The prepared porous matrices are white, free-flowing powders. Among prepared formulations drug PVP K30 (1:1.5) showed maximum Washburn slope of 0.0103. The mean particle size was found to be 0.82 μ and D50 (median) value was found to be 0.55 μ. The scanning of particles at various magnifications by scanning electron microscopy (SEM) analysis revealed that the method had effectively induced porosity. The Q value of valsartan from porous matrices was observed at 20 min with a first order regression value of 0.917. The calculated difference factor (F1) when compared with pure valsartan was observed to be 63.32%. From the values obtained, it was evident that the method amplifies the percentage of drug dissolution between sixfold and eightfold when compared to pure drug. From the absorption studies by the rat gut method, the absorption of porous matrices increased threefold. Conclusion: Porous matrices of valsartan: PVP K30 (1:1.5 ratio) hold promise for the enhancement of solubility and consecutive formulation of controlled release systems even with poorly soluble drugs. PMID:27606260