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Sample records for pvp

  1. Quantitative analysis of povidone (PVP) in drug-PVP matrix using multicomponent analysis.

    PubMed

    Pedersen, G; Kristensen, H G

    1999-01-01

    A method for the quantification of povidone (PVP), in solid dispersions and physical mixtures of the polymer and a very slightly soluble drug substance, has been developed by multicomponent analysis using the concepts of chemometrics. Because the UV-absorbance spectra of PVP is completely overlapped by the UV-absorbance spectra of the drug substance, a direct spectrophotometric method of PVP is impossible. However, UV-spectrophotometric data were analyzed by the Quant + Perkin Elmer software for quantitative multicomponent analysis using chemometrics, and by the optimal method developed using a solvent of pH 7.4, a fast, reliable, and precise detection of PVP was obtained when the content of PVP in the powder sample exceeded 20% (m/m). Two methods were developed by the calibration procedure, using buffers of pH 7.4, respectively pH 8.5. By applying a solvent of pH 8.5, more sample could be taken into use because of the enhanced solubility of the drug substance, and hence it was believed that as more PVP was taken into use, a better prediction of PVP would be obtained. However, as more drug substance was taken into use the UV-absorbance spectrum of PVP was even more overlapped, and an inferior prediction was obtained.

  2. 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.

  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. Water diffusion into radiation crosslinked PVA-PVP network hydrogels

    NASA Astrophysics Data System (ADS)

    Hill, David J. T.; Whittaker, Andrew K.; Zainuddin

    2011-02-01

    A series of hydrogels comprised of crosslinked networks of poly(vinyl alcohol), PVA and poly(vinyl pyrrolidone), PVP, have been prepared using gamma radiolysis of aqueous solutions of the polymers to effect crosslinking of the polymer chains. The molecular weight of the PVA was in the range 75-105 kDa and of PVP was 360 kDa. Gel doses were measured for the polymers and found to be 11 kGy for PVA, 3.7 kGy for PVP and 4.6 kGy for a mixture of PVA and PVP with a mole fraction of PVP of 0.19. The initial water content of the gels was 87.2 wt%. Further water uptake studies were undertaken using both gravimetric and NMR imaging analyses. These studies showed that the uptake processes followed Fickian kinetics with diffusion coefficients ranging from 1.8×10 -11 for the PVA hydrogel to 4.4×10 -11 m 2 s -1 for the PVP hydrogel for radiation doses of 25 kGy and a temperature of 310 K. At 298 K the gravimetric study yielded a diffusion coefficient of 1.5×10 -11 m 2 s -1 whereas the NMR analysis yielded a slightly higher value of 2.0×10 -11 m 2 s -1 for the hydrogel with a mole fraction of PVP of 0.19 and a radiation dose of 25 kGy.

  6. 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.

  7. Theoretical investigation of the hetero-junction effect in PVP-stabilized Au 13 clusters. The role of PVP in their catalytic activities

    NASA Astrophysics Data System (ADS)

    Okumura, Mitsutaka; Kitagawa, Yasutaka; Kawakami, Takashi; Haruta, Masatake

    2008-06-01

    Hybrid density functional calculations have been carried out for Au 13-poly( N-vinyl-2-pyrrolidone), abbreviated as Au 13-PVP, and related model clusters, Au 13-PVP 4, Au 13-PVP-O 2 and Au 13-PVP 4-O 2, to discuss the variation in the electronic structure of Au 13 clusters by PVP adsorption. The calculations have shown that the charge transfer from the adsorbed PVP to Au 13 produces negatively charged O 2 on Au 13-PVP 4. These findings suggest that PVP acts not only as a stabilizer to prevent the aggregation of Au clusters but also as an electron donor to Au clusters. Thus we conclude that the catalytic activities of Au clusters are affected by the adsorbed PVPs.

  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. New investigation in PVP-mediated synthesis of noble metallic nanomaterials.

    PubMed

    Zhang, Weijia; Rosano-Ortega, Genoveva; Hu, Ye; Bai, Litao; Qin, Lidong

    2012-03-01

    As one of the most heavily used starting materials in metallic nanostructure syntheses, PVP has made a series of revolutionary successes. However, the true role of PVP still has not been fully understood. Herein, designed reactions and NMR analyses have been done to prove the redox reaction in PVP-mediated synthesis of metallic nanomaterials. As metal ions are reduced, alpha-pyrrolidone rings of PVP are partially oxidized and form poly(vinyl(pyrrolidone)x-(succinimide)y), which has a crucial surface modification capability for nanocrystals. This new finding provides insight into how PVP manipulates the structures and morphologies by modifying the reaction rate and stabilizing the nanocrystals.

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

    PubMed

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

    2016-12-06

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

  11. Biomimetic Branched Hollow Fibers Templated by Self-assembled Fibrous Polyvinylpyrrolidone (PVP) Structures in Aqueous Solution

    PubMed Central

    Qiu, Penghe; Mao, Chuanbin

    2010-01-01

    Branched hollow fibers are common in nature, but to form artificial fibers with a similar branched hollow structure is still a challenge. We discovered that polyvinylpyrrolidone (PVP) could self-assemble into branched hollow fibers in an aqueous solution after aging the PVP solution for about two weeks. Based on this finding, we demonstrated two approaches by which the self-assembly of PVP into branched hollow fibers could be exploited to template the formation of branched hollow inorganic fibers. First, inorganic material such as silica with high affinity against the PVP could be deposited on the surface of the branched hollow PVP fibers to form branched hollow silica fibers. To extend the application of PVP self-assembly in templating the formation of hollow branched fibers, we then adopted a second approach where the PVP molecules bound to inorganic nanoparticles (using gold nanoparticles as a model) co-self-assemble with the free PVP molecules in an aqueous solution, resulting in the formation of the branched hollow fibers with the nanoparticles embedded in the PVP matrix constituting the walls of the fibers. Heating the resultant fibers above the glass transition temperature of PVP led to the formation of branched hollow gold fibers. Our work suggests that the self-assembly of the PVP molecules in the solution can serve as a general method for directing the formation of branched hollow inorganic fibers. The branched hollow fibers may find potential applications in microfluidics, artificial blood vessel generation, and tissue engineering. PMID:20158250

  12. 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.

  13. 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.

  14. Fatal Intoxication with α-PVP, a Synthetic Cathinone Derivative.

    PubMed

    Potocka-Banaś, Barbara; Janus, Tomasz; Majdanik, Sławomir; Banaś, Tomasz; Dembińska, Teresa; Borowiak, Krzysztof

    2016-12-28

    This study presents the fatal case of a young man who was admitted to the ICAU due to sudden cardiac arrest. An interview revealed that the patient had taken some unspecified crystals. From the moment of admission, his condition deteriorated dramatically as a result of increasing circulatory insufficiency. After a few hours, sudden cardiac arrest occurred again and the patient was pronounced dead. In the course of a medicolegal autopsy, samples of biological material were preserved for toxicology tests and histopathological examination. The analysis of samples using the LC-MS/MS technique revealed the presence of α-PVP in the following concentrations: blood-174 ng/mL, urine-401 ng/mL, brain-292 ng/g, liver-190 ng/g, kidney-122 ng/g, gastric contents-606 ng/g. The study also presents findings from the parallel histopathological examination. Based on these findings, cardiac arrest secondary to intoxication with alpha-PVP was determined as the direct cause of the patient's death.

  15. Preparation of antifouling polyvinylpyrrolidone (PVP 40K) modified polyethersulfone (PES) ultrafiltration (UF) membrane for water purification

    NASA Astrophysics Data System (ADS)

    Vatsha, Banele; Ngila, Jane Catherine; Moutloali, Richard M.

    This study reports the fabrication of polyethersulfone (PES) membrane using the phase inversion method in the presence of polyvinylpyrrolidone (PVP, 40K) as pore-forming agent. The membranes were made from two PES concentration types, i.e. 16 and 18 wt.%. The effect of high molecular weight PVP concentration (2-10%) was examined in order to obtain a membrane with good performance, i.e. high water flux and reasonable Bovine Serum Albumin (BSA, protein model solution) rejection. The optimised membranes were characterised by ATR-FTIR, AFM, SEM, contact angle and dead-end membrane filtration tests. It was found that PVP moieties have positive influence in the prepared PES membranes. SEM surface and cross-sectional images were used to observed morphological changes as PVP content was varied. The pore sizes increased with PVP content for membranes prepared from 16 wt.% PES polymer, whereas at the higher PVP content in 18 wt.% PES membrane, pore sizes tend to decrease or completely disappear. The CA decreased gradually for the 16 wt.% PES with increasing PVP content whereas in the 18 wt.% PES the CA decreased initially before tapering off or increasing slightly. The rejection of BSA solution by both neat PES and PVP-containing PES membrane was above 85%. AFM surface topography exhibited increase in roughness value with PVP content. FTIR/ATR spectra corroborated the functional composition of neat PES and PVP molecule dispersed on PES membrane backbone. The results attained confirmed the potential industrial application of PVP molecule to minimise fouling tendencies.

  16. Synthesis of Polyvinylpyrrolidone (PVP)-Green Tea Extract Composite Nanostructures using Electrohydrodynamic Spraying Technique

    NASA Astrophysics Data System (ADS)

    Kamaruddin; Edikresnha, D.; Sriyanti, I.; Munir, M. M.; Khairurrijal

    2017-05-01

    Green Tea Extract (GTE) as an active substance has successfully loaded to PVP nanostructures using electrohydrodynamic spraying technique. The precursor solution was the mixture of ethanolic polyvinylpyrrolidone (PVP) with a molecular weight of 1,300 kg/mol and ethanolic GTE solutions at a weight concentration of 4 wt.% and 2 wt.%, respectively, and it was estimated that the entanglement number was 2. The electrospraying was conducted at the voltage of 15 kV, the flow rate of 10 µL/min., and the distance between the collector and the tip of the nozzle of 10 cm. The SEM images showed that the PVP/GTE nanostructures had a combination of agglomerated beads (less spherical particles) and nanofibers. This occurred because if the PVP concentration is low, the PVP/GTE composite has weak core structures that cause the shell to be easily agglomerated each other. The intermolecular interaction between PVP and GTE in the PVP/GTE nanostructures occurred as confirmed by the peak at 3396 cm-1, which is the carboxyl group, proving that the PVP/GTE nanostructures contained water, alcohols, and phenols. The peak at 1040 cm-1, which is the stretching of C-O group in amino acid, gave another proof to the intermolecular interaction.

  17. Alpha-PVP as an active component of herbal highs in Poland between 2013 and 2015.

    PubMed

    Byrska, Bogumiła; Stanaszek, Roman; Zuba, Dariusz

    2016-12-30

    Alpha-PVP (alpha-pyrrolidinovalerophenone, α-PVP) is a synthetic derivative of cathinone. It has been one of the most frequently detected new psychoactive substances (NPS) available on the drug market in recent years in Poland. The usual routes of administration of the drug include oral, insufflation, and injection. Unexpectedly, we dealt with a great number of herbal samples that turned out to contain α-PVP. A total number of 352 herbal samples from 19 cases in which we detected synthetic cathinones, were investigated in the Institute of Forensic Research (IFR) from 2013 to 2015. The seized products that were received by our laboratory were first screened by gas chromatography coupled to mass spectrometry (GC-MS). Quantification of α-PVP and other cathinones was performed by ultra-performance liquid chromatography with photodiode array detection (UPLC-PDA). Of the samples, 84% contained only α-PVP. Other groups of products were those containing only α-PVT, α-PVP and α-PVT, α-PVP and synthetic cannabinoid A-834, 735, and α-PVP and cannabis. In one herbal sample, α-PVP was detected along with caffeine and tadalafil. The herbal products present on the market containing only α-PVP usually had a mass of 0.3 to 0.6 g, and concentration range in this group of samples was 3.0-44.0% (content: 13.0-222.0 mg per package). The amount of α-PVP in samples below 0.30 g was in a range 9-18 mg whiles in samples above 0.60 g it was in the range 30-716 mg. There were also products containing a mixture of α-PVP and α-PVT. In those samples, α-PVP concentrations were: 3.0-6.0% (amount: 15.0-34.0 mg). Copyright © 2016 John Wiley & Sons, Ltd.

  18. Effects of PVP/PEI coated and uncoated silver NPs and PVP/PEI coating agent on three species of marine microalgae.

    PubMed

    Schiavo, S; Duroudier, N; Bilbao, E; Mikolaczyk, M; Schäfer, J; Cajaraville, M P; Manzo, S

    2017-01-15

    In the last years, applications for silver nanoparticles (Ag NPs) continue to increase together with the concerns about their potential input and hazards in aquatic ecosystems, where microalgae are key organisms. The aim of the present study was to assess the relative sensitivity of three marine microalgae species with differences in cell wall composition/structure exposed to Poly N-vinyl-2-pirrolidone/Polyethyleneimine (PVP/PEI) coated 5nm Ag NPs and uncoated 47nm Ag NP. As limited attention has been paid to the role of coating agents in NP toxicity, the effect of PVP/PEI alone was also evaluated. After 72h in artificial seawater, 47nm Ag NPs formed around 1400nm size aggregates while PVP/PEI coated 5nm Ag NPs reached around 90nm. Ag(+) release in seawater was around 3% for 47nm Ag NPs and 30% for PVP/PEI coated 5nm Ag NPs. PVP/PEI coated 5nm Ag NP aggregates entrapped the algal cells in a network of heteroaggregates, while uncoated 47nm Ag NPs interacted to a lesser extent with algae. The concentration of PVP/PEI coated 5nm Ag NPs that exerted the median effect (EC50) on algae growth pointed out differences in algae sensitivity: T. suecica was about 10 times more sensitive than I. galbana and P. tricornutum. Further, the coating agent alone was as toxic to algae as PVP/PEI coated 5nm Ag NPs, suggesting that presence of the coating agent was the main driver of toxicity of coated NPs. Uncoated 47nm Ag NPs instead, showed similar toxicity towards algae although P. tricornutum was slightly less sensitive than T. suecica and I. galbana, which agrees with the presence of a resistant silicified cell wall in the diatom. The present work demonstrates differences in sensitivity of three marine microalgae, possibly related to their cell surface and size characteristics. Copyright © 2016 Elsevier B.V. All rights reserved.

  19. 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. © 2015 Wiley Periodicals, Inc. and the American Pharmacists Association.

  20. 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.

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

    PubMed

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

    2015-08-21

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

  2. 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.

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

    SciTech Connect

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

    2016-05-06

    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.

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

    PubMed

    Karpuraranjith, M; Thambidurai, S

    2017-03-06

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

  5. Dielectric and electrical behaviours of polymeric (PEO/PVP):NaIO4 composite for solid electrolytes

    NASA Astrophysics Data System (ADS)

    Marinov, Y. G.; Hadjichristov, G. B.; Petrov, A. G.; Koduru, H. K.; Marino, L.; Scaramuzza, N.

    2017-01-01

    Composite material prepared from polyethylene oxide (PEO) and polyvinylpyrrolidone (PVP) doped with Sodium (meta)periodate (NaIO4) salt was studied by complex impedance spectroscopy at room temperature. The polymers PEO and PVP were mixed in a weight ratio 70:30 %, and the concentration of the embedded NaIO4 compound was 7.5 wt.%. The effect from NaIO4 filler on the dielectric permittivity of the three-component mixed system was analyzed in the frequency range 0.1 Hz - 1 MHz. As compared with the two-component polymer host PEO/PVP, a distinctly enhanced electrical and dielectrical response and an increase of the value of dielectric constant of the polymeric (PEO/PVP):NaIO4 composite were present. This suggests the potential of this material for soft electronics and applications such as solid electrolytes.

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

    PubMed

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

    2008-09-03

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

  7. Synthesis and fabrication of silver nanowires embedded in PVP fibers by near-field electrospinning process

    NASA Astrophysics Data System (ADS)

    Yang, T. L.; Pan, C. T.; Chen, Y. C.; Lin, L. W.; Wu, I. C.; Hung, K. H.; Lin, Y. R.; Huang, H. L.; Liu, C. F.; Mao, S. W.; Kuo, S. W.

    2015-01-01

    In this study, polyol process was used to synthesize anisotropic silver nanowires (AgNWs). The ranges of synthesis temperature from 100 to 200 degrees were explored, and the ranges from 4.53 to 13.75 wt% Polyvinylpyrrolidone (PVP) were investigated. The lengths and diameters of AgNWs from 15 to 30 μm and from 10 to 50 nm can be obtained, respectively. Then, the AgNWs embedded in PVP fibers (PVP/AgNWs) were fabricated by the near-field electrospinning (NFES) process. The AgNWs were broken down into nanoparticles when the applied electric field was over 1.4 × 107 V/m. However, the AgNWs could remain undamaged when the electric field was controlled between 8 × 106 and 1.2 × 107 V/m. Therefore, the threshold electric field can be determined and the diameter of the PVP/AgNWs fibers from 500 nm to 10 μm can be obtained. Next, the characteristics of the PVP/AgNWs were examined by N&K analyzer, four-point probe, EDS and FTIR. The transmittance of PVP/AgNWs films was 51.29-68.97% and the sheet resistance of purified AgNWs was 0.125 Ω/sq which was superior to that of commercial ITO. In addition, the haze of PVP/AgNWs with 30-90 nm thick was from 11.5% to 13.3%. In the near future, the PVP/AgNWs fibers can be used as transparent conductive electrodes.

  8. One step synthesis of the smallest photoluminescent and paramagnetic PVP-protected gold atomic clusters.

    PubMed

    Santiago González, Beatriz; Rodríguez, María J; Blanco, Carmen; Rivas, José; López-Quintela, M Arturo; Gaspar Martinho, José M

    2010-10-13

    Gold atomic clusters of only two and three atoms were prepared by a simple electrochemical technique based on the anodic dissolution of a gold electrode in the presence of PVP, and subsequent electroreduction of the Au-PVP complexes. These clusters show stable photoluminescent and magnetic properties, which make them the smallest and most elemental gold (0) building blocks in nature (after atoms) bringing new possibilities to construct novel nano/microstructures with large potential interest in biomedicine, catalysis, and so forth.

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

    PubMed

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

    2017-06-23

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

  10. Radiation synthesis of PVP/alginate hydrogel containing nanosilver as wound dressing.

    PubMed

    Singh, Rita; Singh, Durgeshwer

    2012-11-01

    Hydrogels with polyvinyl pyrrolidone (PVP) and alginate were synthesized and silver nanoparticles were incorporated in hydrogel network using gamma radiation. PVP (10 and 15 %) in combination with 0.5 and 1 % alginate was gamma irradiated at different doses of 25 and 40 kGy. Maximum gel percent was obtained with 15 % PVP in combination with 0.5 % alginate. The fluid absorption capacity for the PVP/alginate hydrogels was about 1881-2361 % at 24 h. Moisture vapour transmission rate (MVTR) of hydrogels containing nanosilver at 24 h was 278.44 g/(m(2)h). The absorption capacity and moisture permeability of the PVP/alginate-nanosilver composite hydrogel dressings show the ability of the hydrogels to prevent fluid accumulation in exudating wound. The hydrogels containing nanosilver demonstrated strong antimicrobial effect and complete inhibition of microbial growth was observed with 70 ppm nanosilver dressings. PVP/alginate hydrogels containing nanosilver with efficient fluid handling capacity and antimicrobial activity was found suitable for use as wound dressing.

  11. The dynamic magnetoviscoelastic properties of biomineralized (Fe3O4) PVP-CMC hydrogel

    NASA Astrophysics Data System (ADS)

    Ray, Ayan; Saha, Nabanita; Saha, Petr

    2017-05-01

    The Polyvinylpyrrolidone (PVP) and carboxymethylcellulose (CMC) based polymer matrix was used as a template for the preparation of magnetic hydrogel. This freshly prepared PVP-CMC hydrogel template was successfully mineralized by in situ synthesis of magnetic nanoparticles (Fe3O4) via chemical co-precipitation reaction using liquid diffusion method. The present study emphasizes on the rheological behavior of non-mineralized and mineralized PVP-CMC hydrogels. Scanning Electron Microscopy (SEM), transmission electron microscopy (TEM), X-ray Diffraction (XRD) pattern, Fourier transform infrared spectroscopy (FT-TR), Vibrating sample magnetometer (VSM) and dynamic magneto rheometer were used to study the morphological, physical, chemical and magnetic properties of nanoparticle (Fe3O4) filled PVP-CMC hydrogel respectively in order to monitor how Fe3O4 magnetic nanoparticles affects the mechanical properties of the hydrogel network. The storage (G') and loss (G") moduli with a complex viscosity of the system was measured using a parallel plate rheometer. Frequency and amplitude sweep with temperature variation was performed to determine the frequency and amplitude dependent magneto viscoelastic moduli for both hydrogel samples. A strong shear thinning effect was observed in both (non-mineralized and mineralized) PVP-CMC hydrogels, which confirm that Fe3O4 filled magnetic hydrogels, are pseudoplastic in nature. This Fe3O4 filled PVP-CMC hydrogel can be considered as stimuli-responsive soft matter that may be used as an actuator in medical devices.

  12. Formation mechanism of colloidal nanoparticles obtained from probucol/PVP/SDS ternary ground mixture.

    PubMed

    Pongpeerapat, Adchara; Wanawongthai, Chalermphon; Tozuka, Yuichi; Moribe, Kunikazu; Yamamoto, Keiji

    2008-03-20

    The purpose of this study was to investigate the formation mechanism of colloidal nanoparticles after dispersion of probucol/polyvinylpyrrolidone (PVP)/sodium dodecyl sulphate (SDS) ternary ground mixture (GM) into water. Probucol, PVP and SDS were mixed at a weight ratio of 1:3:1 and ground for 30 min with a vibrational rod mill. The morphology and physicochemical properties were investigated through high resolution scanning electron microscopy (SEM), environmental SEM, dynamic light scattering, (13)C NMR and zeta potential measurements. SEM images confirmed the presence of 20 nm size primary particles in the GM powder of probucol/PVP K17/SDS. Spherical nanoparticles with a size of around 100 nm, formed after dispersion of the GM into water, suggested an agglomeration of the primary particles. A further agglomeration of around 160 nm was observed with the stability experiment. Zeta potential and particle size measurements using latex beads revealed that PVPK 17/SDS complex was adsorbed on the probucol particle surface forming a layered structure. A similar agglomeration behavior was observed using the GM of probucol/PVP K12/SDS, though the molecular state of the PVPK 12/SDS complex at the particle surface was different from that of the PVPK 17/SDS complex. (13)C NMR results suggested that intermolecular interactions between PVP K12 and SDS did not reach the same level as the interactions between PVP K17 and SDS. This study proposed a formation mechanism of colloidal nanoparticles.

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

    PubMed

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

    2013-10-01

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

  14. Solid dispersion of carbamazepine in PVP K30 by conventional solvent evaporation and supercritical methods.

    PubMed

    Sethia, S; Squillante, E

    2004-03-19

    This study compares the physicochemical properties of carbamazepine (CBZ) solid dispersions prepared by either a conventional solvent evaporation versus a supercritical fluid process. Solid dispersions of carbamazepine in polyvinylpyrrolidone (PVP) K30 with either Gelucire 44/14 or Vitamin E TPGS, NF (d-alpha-tocopheryl polyethylene glycol 1000 succinate) were prepared and characterized by intrinsic dissolution, differential scanning calorimetry, powder X-ray diffraction and Fourier transform infrared spectroscopy. CBZ/PVP K30 and CBZ/PVP K30/TPGS solid dispersions showed increased dissolution rate. The best intrinsic dissolution rate (IDR) was obtained for supercritically processed CBZ/PVP K30 that was four-fold higher than pure CBZ. Thermograms of various solid dispersions did not show the melting peak of CBZ, indicating that CBZ was in amorphous form inside the carrier system. This was further confirmed by X-ray diffraction studies. Infrared spectroscopic studies showed interaction between CBZ and PVP K30 in solid dispersions. The amorphous state of CBZ coupled with presence of interaction between drug and PVP K30 suggests fewer, if any, stability problems. Because the supercritical-based process produced solid dispersions with IDR better than conventional solid dispersions augmented with amphiphilic carriers, stability issues associated with lipid carriers do not apply, which, in turn, implies easier scale up under current Good Manufacturing Practice for this technique.

  15. 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.

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

    PubMed

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

    2017-01-01

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

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

    PubMed

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

    2017-04-01

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

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

    PubMed

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

    2010-09-01

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

  19. 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.

  20. Effect of Core–Shell Ceria/Poly(vinylpyrrolidone) (PVP) Nanoparticles Incorporated in Polymer Films and Their Optical Properties

    PubMed Central

    Itoh, Toshio; Uchida, Toshio; Izu, Noriya; Matsubara, Ichiro; Shin, Woosuck

    2013-01-01

    We fabricated hybrid films of pentaerythritol triacrylate (PETA) with core–shell ceria/poly(vinylpyrrolidone) (PVP) nanoparticles, which consist of cerium oxide as the core and PVP as the shell, and investigated the film optical properties. In this study, we used ceria/PVP nanoparticles with average diameters of 37, 49 and 91 nm. We obtained translucent films consisting of PETA with core–shell ceria/PVP nanoparticles. The core–shell ceria/PVP nanoparticles can reduce the transmittance of near-ultraviolet light. The transmittance of visible light and haze values depends not only on the thickness of the films, but also on the average diameter of the nanoparticles. A SEM observation and the optical analyses prove that the core–shell ceria/PVP nanoparticles do not aggregate into the PETA matrix. PMID:28809264

  1. 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.

  2. Cytotoxic and proinflammatory effects of PVP-coated silver nanoparticles after intratracheal instillation in rats

    PubMed Central

    Hirn, Stephanie; Wenk, Alexander; Diendorf, Jörg; Epple, Matthias; Johnston, Blair D; Krombach, Fritz; Kreyling, Wolfgang G; Schleh, Carsten

    2013-01-01

    Summary Silver nanoparticles (AgNP) are among the most promising nanomaterials, and their usage in medical applications and consumer products is growing rapidly. To evaluate possible adverse health effects, especially to the lungs, the current study focused on the cytotoxic and proinflammatory effects of AgNP after the intratracheal instillation in rats. Monodisperse, PVP-coated AgNP (70 nm) showing little agglomeration in aqueous suspension were instilled intratracheally. After 24 hours, the lungs were lavaged, and lactate dehydrogenase (LDH), total protein, and cytokine levels as well as total and differential cell counts were measured in the bronchoalveolar lavage fluid (BALF). Instillation of 50 µg PVP-AgNP did not result in elevated LDH, total protein, or cytokine levels in BALF compared to the control, whereas instillation of 250 µg PVP-AgNP caused a significant increase in LDH (1.9-fold) and total protein (1.3-fold) levels as well as in neutrophil numbers (60-fold) of BALF. Furthermore, while there was no change in BALF cytokine levels after the instillation of 50 µg PVP-AgNP, instillation of 250 µg PVP-AgNP resulted in significantly increased levels of seven out of eleven measured cytokines. These finding suggest that exposure to inhaled AgNP can induce moderate pulmonary toxicity, but only at rather high concentrations. PMID:24455451

  3. Optimising patient outcomes with photoselective vaporization of the prostate (PVP): a review

    PubMed Central

    Ow, Darren; Perera, Marlon; Woo, Henry H.; Jack, Greg; Lawrentschuk, Nathan

    2017-01-01

    Benign prostatic hyperplasia (BPH) is a common pathology causing lower urinary tract symptoms (LUTS) and may significantly impact quality of life. While transurethral resection of the prostate (TURP) remains the gold standard treatment, there are many evolving technologies that are gaining popularity. Photoselective vaporization of the prostate (PVP) is one such therapy which has been shown to be non-inferior to TURP. We aimed to review the literature and discuss factors to optimise patient outcomes in the setting of PVP for BPH. A comprehensive search of the electronic databases, including MEDLINE, Embase, Web of Science and The Cochrane Library was performed on articles published after the year 2000. After exclusion, a total of 38 papers were included for review. The evolution of higher powered device has enabled men with larger prostates and those on oral anticoagulation to undergo safely and successfully PVP. Despite continued oral anticoagulation in patients undergoing PVP, the risk of bleeding may be minimised with 5-Alpha Reductase Inhibitor (5-ARI) therapy however further studies are required. Pre-treatment with 5-ARI’s does not hinder the procedure however more studies are required to demonstrate a reliable benefit. Current data suggests that success and complication rate is largely influenced by the experience of the operator. Post-operative erectile dysfunction is reported in patients with previously normal function following PVP, however those with a degree of erectile dysfunction pre-operatively may see improvement with alleviation of LUTS. PMID:28791232

  4. 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.

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

    PubMed

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

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

  6. Influence of a neutral polymer (PVP) on the solvatochromic properties of SDS micelles.

    PubMed

    Shannigrahi, Mrinmoy; Bagchi, Sanjib

    2005-08-04

    In the present work, we have studied the influence of a water-soluble neutral polymer (poly-N-vinyl pyrrolidin-2-one, PVP) on the Kamlet-Taft polarity parameters of sodium n-dodecyl sulfate (SDS) micelles. We have used pyrene as an independent dipolarity/polarizability (pi parameter) descriptor molecule. It has been found that the addition of polymer (0.1 wt % PVP) increases the pi value of SDS micelles, suggesting that PVP-SDS aggregates have a larger dipolarity/polarizability than that of SDS micelles. Linear solvation energy relationships involving the fluorescence transition energy of four structurally similar ketocyanine dyes have also been used to evaluate the polarity parameters. It is interesting to observe that the addition of polymer leads to a decrease in both the hydrogen-bond donation (alpha-parameter) and hydrogen-bond acceptance ability (beta-parameter) of the micellar aggregate formed by PVP-SDS, whereas the dipolarity/polarizability value shows an increasing trend. Moreover, convergent results have been obtained for the pi value for PVP-SDS aggregates, using pyrene as a pi descriptor and ketocyanine dyes as molecular probes.

  7. Termination of pseudopregnancy in rats by silastic-PVP-PGF2 alpha tube.

    PubMed

    Lau, I F; Lemarbre, P M; Chauvin, C; Saksena, S K

    1979-05-01

    The efficacy of a one-end or both-end open Silastic-polyvinyl-pyrrolidone (Silastic-PVP) tube containing 600 microgram prostaglandin-F2 alpha (PGF2 alpha) and placed subcutaneously on day-6 of pseudopregnancy (PSP) in the induction of premature termination of PSP was compared. A both-end open Silastic-PVP-PGF2 alpha tube was more efficacious in inducing an early termination of PSP with a mean duration of 7.8 days. By contrast, PSP females receiving a one-end open Silastic-PVP-PGF2 alpha tube showed a mean duration of PSP of 9.9 days. The shortened duration of PSP in both these treatment groups was significantly different from the control value of 13.1 days. The significant drop in progesterone (delta 4P) but rise in 20 alpha-dihydroprogesterone (20 alpha-DHP) occurred 24 hr after treatment in PSP rats treated with both-end open Silastic-PVP-PGF2 alpha tube, whereas similar changes in delta 4P and 20 alpha-DHP took place 48-72 hr after the deposition of a one-end open Silastic-PVP PGF2 alpha tube. It is concluded than an initial larger amount of circulating PGF2 alpha is needed to induce an early premature termination of PSP. The exposure of corpus luteum to a more sustained but lower level of PGF2 alpha leads to a slower response.

  8. Preparation and characterization of (PVP + NaClO4) electrolytes for battery applications.

    PubMed

    Subba Reddy, Ch V; Jin, A-P; Zhu, Q-Y; Mai, L-Q; Chen, W

    2006-04-01

    A sodium ion-conducting polymer electrolyte based on polyvinyl pyrrolidone (PVP) complexed with NaClO(4) was prepared using the solution-cast technique. The cathode film of V(2)O(5) xerogel modified with polyvinyl pyrrolidone was prepared using the sol-gel method. Investigations were conducted using X-ray diffractometry (XRD), Fourier transformation infrared (FT-IR) spectroscopy. The ionic conductivity and transference number measurements were performed to characterize the polymer electrolyte for battery applications. The transference number data indicated that the conducting species in these electrolytes are the anions. Using the electrolyte, electrochemical cells with a configuration Na/(PVP + NaClO(4))/V(2)O(5) modified by (PVP) were fabricated and their discharge profiles studied.

  9. 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).

  10. 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. Copyright © 2012 Elsevier Ltd. All rights reserved.

  11. Fluorescence diagnosis of bladder cancer with new water soluble hypericin bound to polyvinylpyrrolidone: PVP-hypericin.

    PubMed

    Kubin, Andreas; Meissner, Philipp; Wierrani, Franz; Burner, Ursula; Bodenteich, Angelika; Pytel, Akos; Schmeller, Nikolaus

    2008-01-01

    Although conventional white light endoscopy (WLE) is currently the gold standard for diagnosing bladder tumors, rates of false negative results and residual tumors after transurethral resection are relatively high. The goal of the present clinical study is to investigate whether using new water soluble hypericin (PVP-hypericin) as a fluorescent dye improves bladder cancer detection and diagnosis. Following instillation of PVP-hypericin (total amount of 0.25 mg hypericin bound to 25 mg polyvinylpoyrrolidone [PVP], reconstituted in 50 mL phys. sodium chloride solution), WLE and fluorescence cystoscopy (photodynamic diagnosis; PDD) were performed on patients with suspected primary or recurrent bladder malignancies (n = 57). Incubation time was 1-2 h and biopsies (n = 163) were taken from fluorescing regions and/or from regions which were suspicious under WLE. Histological investigations of the biopsies provided the final proof of malignancy (or the counterevidence). Results indicated that overall sensitivity with PVP-hypericin and PDD is significantly higher (95%) than with WLE (85%). The sensitivity of PDD in the diagnosis of carcinoma in situ (n = 12) was 100% compared with 33% for WLE. In the diagnosis of dysplasia, the sensitivity of PDD was 85% compared with 31% for WLE. PDD has a positive predictive value (PPV) of 0.75% and a negative predictive value (NPV) of 0.86%, in comparison to WLE PPV = 0.66% NPV = 0.58%. Biopsies were not taken from healthy tissues, thus specificity was markedly lower in our study (53%) than that reported in other studies (98-100%). As a conclusion, PDD using PVP-hypericin is superior to WLE in terms of sensitivity in the diagnosis of malignancies of the bladder. Results suggest that PVP-hypericin is a promising formulation for various diagnostic and therapeutic applications.

  12. Cloning the PvP5CS gene from common bean (Phaseolus vulgaris) and its expression patterns under abiotic stresses.

    PubMed

    Chen, Ji-Bao; Wang, Shu-Min; Jing, Rui-Lian; Mao, Xin-Guo

    2009-01-01

    A full-length cDNA denominated PvP5CS for Delta(1)-pyrroline-5-carboxylate synthetase (P5CS), an enzyme involved in the biosynthesis of proline, was cloned from common bean using a candidate gene approach. PvP5CS contains an open reading frame encoding a 716 amino acid polypeptide. Sequence analysis showed that PvP5CS shares 95.1% homology in nucleotide sequence and 93.2% identity in amino acid sequence with the mothbean (Vigna aconitifolia) P5CS. The expression patterns of PvP5CS in common bean treated with drought, cold (4 degrees C), and salt (200 mM NaCl) stresses were examined using real-time quantitative PCR. These abiotic stresses caused significant up-regulation of the expression of PvP5CS in leaves. The PvP5CS mRNA transcript increased to 2.5 times the control level after 4d drought stress. A rapid up-regulation of PvP5CS, to about 16.3 times the control at 2h post-treatment was observed under salt stress. A significant increase in PvP5CS expression (11.7-fold) was detected after 2h of cold stress. The peaks of proline accumulation appeared at 8d for drought, 24h for cold and 9h for salt stress, somewhat later than the peaks of PvP5CS expression. These results suggest that PvP5CS was a stress-inducible gene regulating the accumulation of proline in plants subjected to stress. Finally, subcellular localization assays showed that the PvP5CS protein was present in the nucleus and at the plasmalemma.

  13. Chitosan-PVP-nano silver oxide wound dressing: in vitro and in vivo evaluation.

    PubMed

    Archana, D; Singh, Brijesh K; Dutta, Joydeep; Dutta, P K

    2015-02-01

    The main aim of this work was to prepare wound healing material with chitosan, poly vinyl pyrrolidone (PVP), silver oxide nanoparticles. The prepared chitosan, chitosan-PVP-nano silver oxide (CPS) films were characterized for their thermal behaviour, morphological properties, mechanical properties, antibacterial properties and wound healing properties. The CPS film found higher antibacterial activity because the materials both chitosan as well as silver oxide poses good antibacterial activity. L929 cell lines were for cytotoxicity study and Adult male albino rats (140-180 g) were used for wound healing study. The prepared film has more wound healing property than of cotton gauge, 100% chitosan and other reported chitosan based dressings.

  14. Characterization of HPMC/PVP polymer blend films using WAXS technique

    NASA Astrophysics Data System (ADS)

    Prakash, Y.; Somashekarappa, H.; Parameswara, P.; Demappa, T.; Somashekar, R.

    2012-06-01

    Hydroxy propyl methyl cellulose (HPMC) and Poly vinyl pyrrolidone (PVP) polymer blend films were prepared and investigated using X-ray line profile analysis method. Here an attempt has been made to study the changes in the crystallite size and lattice strain in HPMC with the increase in concentration of PVP. Decrease in these microcrystalline parameters implies increase in the amorphous nature of the film giving more flexibility, degradability and good miscibility. Micro structural parameters reveals that the blend films have more amorphous nature than virgin HPMC. This further justified by SEM images which indicate better miscibility of the two polymers in the blend matrix.

  15. 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.

  16. Effects of Nanoparticle Size on Cellular Uptake and Liver MRI with PVP-Coated Iron Oxide Nanoparticles

    PubMed Central

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

    2010-01-01

    The effect of nanoparticle size (30–120 nm) on magnetic resonance imaging (MRI) of hepatic lesions in vivo has been systematically examined using polyvinylpyrrolidone (PVP)-coated iron oxide nanoparticles (PVP-IOs). Such biocompatible PVP-IOs with different sizes were synthesized by a simple one-pot pyrolysis method. These PVP-IOs exhibited good crystallinity and high T2 relaxivities, and the relaxivity increased with the size of the magnetic nanoparticles. It was found that cellular uptake changed with both size and surface physiochemical properties, and that PVP-IO-37 with a core size of 37 nm and hydrodynamic particle size of 100 nm exhibited higher cellular uptake rate and greater distribution than other PVP-IOs and Feridex. We systematically investigated the effect of nanoparticle size on MRI of normal liver and hepatic lesions in vivo. The physical and chemical properties of the nanoparticles influenced their pharmacokinetic behavior, which ultimately determined their ability to accumulate in the liver. The contrast enhancement of PVP-IOs within the liver was highly dependent on the overall size of the nanoparticles, and the 100 nm PVP-IO-37 nanoparticles exhibited the greatest enhancement. These results will have implications in designing engineered nanoparticles that are optimized as MR contrast agents or for use in therapeutics. PMID:21043459

  17. Preparation of PVDF porous membranes by using PVDF-g-PVP powder as an additive and their antifouling property

    NASA Astrophysics Data System (ADS)

    Xu, Chenqi; Huang, Wei; Lu, Xin; Yan, Deyue; Chen, Shutao; Huang, Hua

    2012-11-01

    The hydrophilic PVDF-g-PVP powder was used as additive to prepare a series of PVDF/PVDF-g-PVP blend porous membranes via an immersion precipitation phase inversion process. FTIR-ATR measurements confirmed that the hydrophilic PVP preferentially segregated to the interface between membrane and coagulant. SEM images showed that there was no big change in the membrane cross-section with the amount of PVDF-g-PVP increased. However, the membrane surface roughness increased with the amount of PVDF-g-PVP increased according to AFM data. The mean pore size of membranes reached max when the amount of PVDF-g-PVP was 10 wt%. The water contact angle and filtration experiments revealed that the surface enrichment of PVP endowed the membranes with significantly enhanced surface hydrophilicity and protein-adsorption resistance. The flux recovery of the porous membranes was increased from 37.50% to 77.23% with the amount of PVDF-g-PVP increased from 0 to 50 wt%, also indicating that the antifouling property of the porous membranes was improved.

  18. Thermal stability and electrochemical properties of PVP-protected Ru nanoparticles synthesized at room temperature

    NASA Astrophysics Data System (ADS)

    Kumar, Manish; Devi, Pooja; Shivling, V. D.

    2017-08-01

    Stable ruthenium nanoparticles (RuNPs) have been synthesized by the chemical reduction of ruthenium trichloride trihydrate (RuCl3 · 3H2O) using sodium borohydride (NaBH4) as a reductant and polyvinylpyrrolidone (PVP) as a protecting agent in the aqueous medium at room temperature. The nanoparticles thus prepared were characterized by their morphology and structural analysis from transmission electron microscopy (TEM), X-ray powder diffraction (XRD), UV-vis spectroscopy, Fourier transformation infrared and thermogravimetric analysis (TGA) techniques. The TEM image suggested a homogeneous distribution of PVP-protected RuNPs having a small average diameter of 2-4 nm with a chain-like network structure. The XRD pattern also confirmed that a crystallite size is around 2 nm of PVP-protected RuNPs having a single broad peak. The thermal stability studied using TGA, indicated good stability and the electrochemical properties of these nanoparticles revealed that saturation current increases for PVP-protected RuNPs/GC.

  19. One-pot synthesis of responsive catalytic Au@PVP hybrid nanogels.

    PubMed

    Xiao, Chuanfu; Chen, Shoumin; Zhang, Laiying; Zhou, Shuiqin; Wu, Weitai

    2012-12-14

    Responsive catalytic hybrid nanogels with Au nanoparticle cores and a polyvinylpyrrolidone (PVP) based gel shell are prepared through a novel one-pot approach. The embedded Au nanoparticles demonstrate both a pH-modulated catalytic activity and anti-aggregation properties upon recycling.

  20. Stability and solubility of celecoxib-PVP amorphous dispersions: a molecular perspective.

    PubMed

    Gupta, Piyush; Kakumanu, Vasu Kumar; Bansal, Arvind K

    2004-10-01

    The purpose of the current study is to evaluate the solubility advantage offered by celecoxib (CEL) amorphous systems and to characterize and correlate the physical and thermodynamic properties of CEL and its amorphous molecular dispersions containing poly(vinylpyrrolidone) (PVP). The measurement of crystalline content, glass transition temperatures, and enthalpy relaxation was performed using differential scanning calorimetry. Solubility and dissolutions studies were conducted at 37 degrees C to elucidate release mechanisms. Further, the amorphous systems were characterized by polarized light microscopy and X-ray powder diffraction studies. The PVP content has a prominent effect on the stability and solubility profiles of amorphous systems. A dispersion of 20% w/w PVP with CEL resulted in a maxima in terms of solubility enhancement and lowering of relaxation enthalpy. The release of drug from amorphous molecular dispersions was found to be drug-dependent and independent of the carrier. The solubility enhancement and enthalpy relaxation studies with respect to PVP concentration helped in a better prediction of role of carrier and optimization of concentration in the use of solid dispersions or amorphous systems. The drug release mechanism is drug-controlled rather than carrier-controlled.

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

    PubMed

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

    2010-08-01

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

  2. Anomalous dissolution behavior of celecoxib in PVP/Isomalt solid dispersions prepared using spray drier.

    PubMed

    Ghanavati, Roya; Taheri, Azade; Homayouni, Alireza

    2017-03-01

    Celecoxib is a COX II inhibitor NSAID which is used for joint pains, rheumatoid arthritis and osteoarthritis, however due to its poor water solubility it shows very low oral bioavailability. Using solid dispersion formulations is one of the most promising strategies to increase solubility of poorly water soluble drugs. The purpose of this study is dissolution enhancement of celecoxib by preparation of solid dispersions via spray drying technique using PVP and Isomalt as hydrophilic carriers. Different ratios of celecoxib, Isomalt and PVP K30 (7:3:0, 5:5:0, 3:7:0, 1:9:0 and 3:5:2, 3:2:5) were prepared from 2% hydroalcoholic solutions (70:30 ethanol:water) using spray drier. Particle size analyzing, saturation solubility, SEM, DSC, FT-IR, XRPD and dissolution studies in 0.25% SDS and 0.04M Na3HPO4 mediums were performed. Stability of samples was also studied after a week and a month storage at 75% humidity condition. The results showed that the saturation solubility of celecoxib in solid dispersion samples is 20-30 folds higher than raw celecoxib. Similar results have been shown for dissolution studies. Solid state analyses showed glass solution state of celecoxib in PVP/Isomalt matrixes. FTIR studies exhibited the formation of hydrogen bonding between celecoxib and PVP in these samples. Spray dried celecoxib (amorphous celecoxib) without usage of carrier showed lower dissolution rate compare to its crystalline state (in 0.25% SDS dissolution medium) whilst these results is vise versa in Na3PO4 dissolution medium. Interestingly almost all samples exhibited higher dissolution rate (in 0.25% SDS) after storage in 75% humidity. XRPD analysis demonstrated the crystallization of amorphous celecoxib after 1month storage. In general using PVP K30 and Isomalt as hydrophilic carriers could increase solubility and dissolution rate of celecoxib in solid dispersion formulations.

  3. Amorphous solid dispersions of sulfonamide/Soluplus® and sulfonamide/PVP prepared by ball milling.

    PubMed

    Caron, Vincent; Hu, Yun; Tajber, Lidia; Erxleben, Andrea; Corrigan, Owen I; McArdle, Patrick; Healy, Anne Marie

    2013-03-01

    The aim of this paper is to investigate the physicochemical properties of binary amorphous dispersions of poorly soluble sulfonamide/polymeric excipient prepared by ball milling. The sulfonamides selected were sulfathiazole (STZ), sulfadimidine (SDM), sulfamerazine (SMZ) and sulfadiazine (SDZ). The excipients were polyvinylpyrrolidone (PVP) and polyvinyl caprolactam-polyvinyl acetate-polyethylene glycol graft co-polymer, commercially known as Soluplus®. Co-milled systems were characterised by powder X-ray diffraction and differential scanning calorimetry. PVP was shown to form amorphous dispersions over a wider composition range than Soluplus® for the four sulfonamides tested. Moreover, amorphous dispersions made with PVP were homogeneous [single glass transition (Tg)], while amorphous dispersions made from Soluplus® were heterogeneous (two Tgs). This behaviour is consistent with the fact that all the sulfonamides tested presented a lower solubility in Soluplus® than in PVP, as evidenced by Flory-Huggins parameters determined. Amorphous dispersions of SDM with Soluplus® could be produced even though SDM does not amorphise alone upon milling and Soluplus® presents Tg at a lower temperature than SDM. Amorphous dispersions of SMZ could be prepared with a lower excipient concentration compared to STZ, SDM and SDZ, which may reflect the one-dimensional H-bonding network in SMZ compared to the 2D or 3D H-bonding network found in the other sulfonamides. Stability tests (60% RH/25°C) revealed that dispersions made with Soluplus® remained dry and powdery compared to those made with PVP that formed a sticky paste in less than 2 weeks, indicating a possible advantage of using Soluplus® in terms of increased physical stability under high humidity storage conditions.

  4. Physical stability of the amorphous state of loperamide and two fragment molecules in solid dispersions with the polymers PVP-K30 and PVP-VA64.

    PubMed

    Weuts, Ilse; Kempen, Dieter; Decorte, Annelies; Verreck, Geert; Peeters, Jef; Brewster, Marcus; Van den Mooter, Guy

    2005-06-01

    The purpose of the present study was to investigate the impact of intermolecular forces on the stability of the amorphous state of loperamide and two of its fragment molecules (4-dimethylamino-N,N-dimethyl-2,2-diphenyl-butyramide (F1) and 4-(4-chlorophenyl)-4-piperidinol (F2)) in solid dispersions with PVP-K30 and PVP-VA64. The stability of originally homogeneous and amorphous dispersions was investigated under different storage conditions. The chemical stability of the compounds was evaluated with HPLC. TGA-analysis was used in order to assess the amount of water in the samples, whereas MT-DSC-measurements were performed to investigate changes in the physical state of the compounds caused by the storage procedure. TGA-analysis reveals a higher uptake of water in humid conditions of the dispersions with PVP-K30 in comparison to those with PVP-VA64, hereby reflecting the more hydrophilic nature of the former polymer. This water acts as a plasticizing agent resulting in an increased mobility and decreased glass transition temperature. Since the degree of supersaturation and the molecular mobility have an influence on the stability of the amourphous state, both parameters were assessed. With respect to the degree of supersaturation of the compounds in the dispersions, the materials seem to be very much alike. Therefore it was postulated that the induction of crystallization in the F1/polymer dispersions stored at high RH (52%) is due to higher molecular mobility of this compound in the dispersions in comparison to F2. The hydrogen bonds that are being formed between F2 and the polymers reduce its mobility and secure this compound from crystallization upon storage, thus indicating the importance of specific interactions with respect to stability issues of solid dispersions. No hydrogen bonds are formed between F1 and the polymers. As a result, the stability of the amorphous state of the compound is being compromised and crystallization takes place. Loperamide, that

  5. Effect of chirality on PVP/drug interaction within binary physical mixtures of ibuprofen, ketoprofen, and naproxen: a DSC study.

    PubMed

    Ivanov, Ivan T; Tsokeva, Zhivka

    2009-08-01

    We report on the thermal behavior of freshly prepared binary drug/polymer physical mixtures that contained ibuprofen, ketoprofen, or naproxen as a drug, and polyvinylpyrrolidone (PVP), hydroxyethylcellulose (HEC), or methylcellulose (MC) as excipient. At 6-10 degrees C/min heating rates the DSC detected a sharp, single endotherm that corresponds to the melting of drug. On heating physical mixtures of PVP and racemic ibuprofen or ketoprofen at lower heating rates, another endotherm was registered in front of the original one. To observe the additional endotherm, specific minimal values of the heating rate and of PVP weight fraction were needed; for ibuprofen and ketoprofen they were 1.5 and 2.0 degrees C/min, and 5 and 15% (w/w), respectively. At greater PVP weight fractions the top temperatures, T(mp), of both peaks were reduced almost linearly indicating strong solid-state interfacial reaction between the drug particles and PVP matrix. The additional endotherm was abolished at greater heating rates (2 degrees C/min for ibuprofen, 3 degrees C/min for ketoprofen), by replacing the racemate with respective S+-enantiomer and by replacing PVP with HEC and MC. Hence, the possible inclusion of enantioselective component within the PVP/drug interaction, responsible for the amorphization of physical mixture over storage, is assumed.

  6. 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.

  7. Synthesis of persulfate containing poly ( N-vinyl-2-pyrrolidone) (PVP) hydrogels in aqueous solutions by γ-induced radiation

    NASA Astrophysics Data System (ADS)

    Kaplan Can, Hatice

    2005-04-01

    The effect of 60Co γ-irradiation on aqueous solutions of poly( N-vinyl-2-pyrrolidone) (PVP) in the presence of persulfate anion has been investigated. The gelation dose of PVP and persulfate containing PVP aqueous solutions has been determined. At low concentrations of persulfate (1.00-3.50%), gelation percentages exhibited a decreasing trend by increasing persulfate content in aqueous solutions of the polymer. The gelation doses of persulfate containing polymer solutions were calculated by the Charlesby-Pinner equation. It was observed that the gelation dose values were shifted to higher values by increasing persulfate concentration in solution. The ratio of the chain scission and crosslinking yields ( G( s)/ G( x)) was also determined. The results showed that the G( s)/ G( x) ratios were smaller than one for PVP aqueous solution system, whereas those obtained for persulfate containing PVP aqueous solutions were higher than unity. The results implied that the chain scission of polymer is more effective than crosslinking in the presence of persulfate. Mechanism of the crosslinking and/or degradation and structure-property relationship of PVP and PVP/persulfate hydrogel systems were investigated by Fourier transformation infeared and thermal analysis (differential scanning calorimetry, thermal gravimetric analysis and differential thermai analysis) methods.

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

    PubMed

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

    2006-09-14

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

  9. 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. Copyright © 2015 Elsevier B.V. All rights reserved.

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

    PubMed Central

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

    2015-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2010-12-01

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

  12. The effect of environmentally relevant conditions on PVP stabilised gold nanoparticles.

    PubMed

    Hitchman, Adam; Smith, Gregory H Sambrook; Ju-Nam, Yon; Sterling, Mark; Lead, Jamie R

    2013-01-01

    Nanoparticles are a major product from the nanotechnology industry and have been shown to have a potentially large environmental exposure and hazard. In this study, sterically stabilised polyvinyl pyrrolidone (PVP) 7 nm gold nanoparticles (NPs) were produced and characterised as prepared by surface plasmon resonance (SPR), size and aggregation, morphology and surface charge. Changes in these properties with changes in environmentally relevant conditions (pH, ionic strength, Ca concentration and fulvic acid presence) were quantified. These sterically stabilised NPs showed no aggregation with changes in pH or inorganic ions, even under high (0.1 M) Ca concentrations. In addition, the presence of fulvic acid resulted in no observable changes in SPR, size, aggregation or surface chemistry, suggesting limited interaction between the PVP stabilised nanoparticles and fulvic acid. Due to the lack of aggregation and interaction, these NPs are expected to be highly mobile and potentially bioavailable in the environment.

  13. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2009-05-01

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

  15. 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.

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

    SciTech Connect

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

    2017-01-01

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

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

    SciTech Connect

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

    2016-05-23

    A series of polyvinyl alcohol (PVA)/polyvinyl pyrrolidone (PVP) polymer blends added with different concentrations of cupric sulphate (CuSO{sub 4}) 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 CuSO{sub 4}. 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 CuSO{sub 4} increases. These films were suitable for electro chemical applications.

  18. Studies on electrical and optical properties of PVP:KIO4 complexed polymer electrolyte films

    NASA Astrophysics Data System (ADS)

    Ravi, M.; Kiran Kumar, K.; Narasimha Rao, V. V. R.

    2015-02-01

    Solid polymer electrolytes based on poly (vinyl pyrrolidone) (PVP) complexed with potassium periodate (KIO4) salt at different weight percent ratios were prepared using solution- cast technique. X- ray diffraction (XRD) results revealed that the amorphous nature of PVP polymer matrix increased with the increase of KIO4 salt concentration. Electrical conductivity was measured with an AC impedance analyzer in the frequency and temperature range 1 Hz-1 MHz and 303 K-373 K respectively. The maximum ionic conductivity 1.421×10-4Scm-1 was obtained for 15 wt% KIO4 doped polymer electrolyte at room temperature. The variation of ac conductivity with frequency obeyed Jonscher power law. Optical absorption studies were performed in the wavelength range 200-600 nm and the absorption edge, direct band gap and indirect band gap values were evaluated.

  19. 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.

  20. Effects of sodium hypochlorite exposure mode on PES/PVP ultrafiltration membrane degradation.

    PubMed

    Causserand, Christel; Pellegrin, Bastien; Rouch, Jean-Christophe

    2015-11-15

    Drinking water production plants using membrane filtration processes report membrane failure issues. According to the literature, membrane degradation is often induced by exposure to sodium hypochlorite, an oxidant widely used during in-place cleanings. The present study focused on quantifying the effect of membrane exposure mode to hypochlorite on properties modifications of a PES/PVP ultrafiltration membrane widely used for drinking water production. For this purpose effects of sodium hypochlorite concentration, contact duration and exposure mode (static or dynamic) were investigated. The pH of the hypochlorite solution was set to 8 as it was demonstrated in numerous previous works that the pH range 7-8 leads to the most severe modification in the membrane characteristics. Membrane degradation was monitored at molecular scale by attenuated total reflectance infrared spectroscopy and at macroscopic scale by pure water permeability and elongation at break measurements. The results obtained in static (soaking) and dynamic (filtration and filtration/backwashing cycles) hypochlorite exposure modes indicated that PES/PVP membrane degradation progress was predominantly governed by hypochlorite oxidation rate. In the tested conditions, mechanical stress (pressure differentials) did not significantly contribute to membrane ageing. The correlation between molecular and macroscopic characterizations demonstrated that PVP degradation is responsible for the membrane integrity loss. A linear relationship between the loss of ductility of the membrane and the progress of the PVP degradation was obtained whatever the exposure mode. Thanks to experiments conducted at various hypochlorite concentrations and exposure durations, the hypochlorite dose parameter (hypochlorite concentration times contact time), widely used in the literature, was demonstrated to be inappropriate to describe the degradation rate: the hypochlorite concentration impact was shown to be dominating the

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

    PubMed

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

    2016-02-01

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

  2. Pharmacological Effects of Methamphetamine and Alpha-PVP Vapor and Injection

    PubMed Central

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

    2016-01-01

    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

  3. 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.

  4. Design of PVP/VA S-630 based tadalafil solid dispersion to enhance the dissolution rate.

    PubMed

    Choi, Jin-Seok; Park, Jeong-Sook

    2017-01-15

    Tadalafil (TDF) is a Biopharmaceutics Classification System (BCS) class II drug; the efficacy thereof is critically limited by inherent poor water solubility. Solid dispersion (SD) techniques are widely used to improve the bioavailability of drugs that are poorly water-soluble. Herein, we used an SD technique to improve the solubility and in vitro dissolution rate of TDF; a solvent evaporation method was applied involving the use of hydrophilic carriers (PVP/VA S-630) and assistants (malic acid or meglumine). The TDF-SD formulations were evaluated in terms of the solubility, in vitro dissolution, and stability. Physical properties were confirmed by field-emission scanning electron microscopy, differential scanning calorimetry, powder X-ray diffraction, and Fourier transform infrared spectroscopy (FT-IR). TDF-SD formulations containing assistants (malic acid or meglumine) and various solubilizers exhibited significantly enhanced solubility in distilled water (DW) (up to 27.3-fold; 18.5±0.16μg/mL with PVP/VA S-630) compared with TDF alone (0.73±0.08μg/mL). However, the dissolution rate of malic acid based formulation was decreased as the PVP/VA S-630 content increased compared to meglumine based formulation. Thus, the optimal TDF-SD formulation (TDF/meglumine/PVP/VA S-630/Aerosil 200: 1/3/5/3) exhibited a greater dissolution rate (89.1±3.9%) than TDF alone (6.2±2.5%) and Cialis(®) powder (16.0±1.9%) in DW. The final TDF-SD formulation was amorphous in nature and exhibited good stability. In conclusion, TDF-SD was successfully improved in vitro dissolution rate of TDF compared to commercial products (Cialis(®)) in the dissolution media without sodium lauryl sulfate (SLS). Copyright © 2016 Elsevier B.V. All rights reserved.

  5. 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.

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

    PubMed Central

    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

  7. Photo physical studies of PVP arrested ZnS quantum dots

    NASA Astrophysics Data System (ADS)

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

    2017-03-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2017-02-01

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

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

    PubMed

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

    2013-03-05

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

  10. Viscoelastic behavior of mineralized (CaCO3) chitin based PVP-CMC hydrogel scaffolds

    NASA Astrophysics Data System (ADS)

    Čadež, Vida; Saha, Nabanita; Sikirić, Maja Dutour; Saha, Petr

    2017-05-01

    Enhancement of the mechanical as well as functional properties of the perspective mineralized PVP-CMC-CaCO3 hydrogel scaffold applicable for bone tissue engineering is quite essential. Therefore, the incorporation feasibility of chitin, a bioactive, antibacterial and biodegradable material, was examined in order to test its ability to enchance mechanical properties of the PVP-CMC-CaCO3 hydrogel scaffold. Chitin based PVP-CMC hydrogels were prepared and characterized both as non-mineralized and mineralized (CaCO3) form of hydrogel scaffolds. Both α-chitin (commercially bought) and β-chitin (isolated from the cuttlebone) were individually tested. It was observed that at 1% strain all hydrogel scaffolds have linear trend, with highly pronounced elastic properties in comparison to viscous ones. The complex viscosity has directly proportional behavior with negative slope against angular frequency within the range of ω = 0.1 - 100 rad.s-1. Incorporation of β-chitin increased storage modulus of all mineralized samples, making it interesting for further research.

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

    PubMed

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

    2011-07-15

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

  12. 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.

  13. Photo physical studies of PVP arrested ZnS quantum dots

    NASA Astrophysics Data System (ADS)

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

    2016-12-01

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

  14. 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%.

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

    PubMed

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

    2012-08-01

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

  16. PVP immobilized SiO2 nanospheres for high-performance shear thickening fluid

    NASA Astrophysics Data System (ADS)

    Liu, Mei; Chen, Qian; Wang, Sheng; Bai, Linfeng; Sang, Min; Jiang, Wanquan; Xuan, Shouhu; Gong, Xinglong

    2017-07-01

    We develop a modified method to improve the rheological performance of SiO2-based shear thickening fluid (STF). Directly adding surfactant into STF is the most common method to improve the rheological performance of SiO2-based STF. However, the final viscosity increases quickly with the increase of shear rate, which is against for the practical applications. In this work, SiO2 nanospheres are firstly modified by PVP K30 through an ethanol refluxing method and the modified SiO2 nanospheres are used to prepare PVP@SiO2-STF. Compared with the unmodified SiO2 based STF (SiO2-STF), the PVP@SiO2-STF presents an obvious increase of shear thickening (ST) effects and the maximum viscosity increases by 7 times and the critical shear rates decrease about 10 times approximately. A reasonable explanation is proposed to interpret the influence of the modification methods on the rheological properties of STF. This work provides a new way to control the shear thickening behavior and also contributes to understand the mechanism of ST effect, which has an important significance to develop controllable STF.

  17. 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.

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

    PubMed Central

    Khodaverdi, Elham; Khalili, Noman; Zangiabadi, Farzad; Homayouni, Alireza

    2012-01-01

    Objective(s) The purpose of the present study was to use the solid dispersion (SD) technique to improve the dissolution rates of indomethacin (IMC). Materials and Methods IMC solid dispersions in PVP K30 and isomalt (GALEN IQ 990) were prepared using the solvent evaporation technique and a hot melt method in weight ratios of 2, 10 and 30% (IMC:PVP). Solid dispersions and physical mixtures were characterized by X-ray powder diffraction (XRPD), differential scanning calorimetry (DSC) and dissolution test. Physical stability tests were also performed at different temperatures and humidity conditions. Results The dissolution rates of all solid dispersions were faster than those of their physical mixtures. In samples containing 2% or 10% of IMC, there were no significant differences between the dissolution rates of IMC in PVP and isomalt solid dispersions, but in samples containing 30% of IMC, the dissolution rates were higher in isomalt dispersions. The XRPD analysis showed no crystalline peaks in solid dispersions, indicating that IMC was amorphous within the carrier. The DSC results showed that an interaction occurred between the drug and the carrier in PVP and isomalt dispersions. Physical stability tests at severe storage conditions showed that the dissolution rate of IMC in PVP solid dispersions decreased, while the dissolution profile of IMC in isomalt solid dispersions did not change significantly. Conclusion It was shown that the dissolution rates of IMC in PVP and isomalt solid dispersions were substantially increased compared with their physical mixtures and pure IMC. PMID:23493157

  19. Synthesis and characterization of PVP-coated large core iron oxide nanoparticles as an MRI contrast agent

    PubMed Central

    Lee, Ha-Young; Lee, Sang-Hoon; Xu, Chenjie; Xie, Jin; Lee, Jin-Hyung; Wu, Bing; Koh, Ai Leen; Wang, Xiaoying; Sinclair, Robert; Wang, Shan X; Nishimura, Dwight G; Biswal, Sandip; Sun, Shouheng; Cho, Sun Hang; Chen, Xiaoyuan

    2010-01-01

    The purpose of this study was to synthesize biocompatible polyvinylpyrrolidone (PVP)-coated iron oxide (PVP-IO) nanoparticles and to evaluate their efficacy as a magnetic resonance imaging (MRI) contrast agent. The PVP-IO nanoparticles were synthesized by a thermal decomposition method and characterized by x-ray diffraction (XRD), transmission electron microscopy (TEM), dynamic light scattering (DLS), and a superconducting quantum interface device (SQUID). The core size of the particles is about 8–10 nm and the overall size is around 20–30 nm. The measured r2 (reciprocal of T2 relaxation time) and r2∗ (reciprocal of T2∗ relaxation time) are 141.2 and 338.1 (s mM)−1, respectively. The particles are highly soluble and stable in various buffers and in serum. The macrophage uptake of PVP-IO is comparable to that of Feridex as measured by a Prussian blue iron stain and phantom study. The signal intensity of a rabbit liver was effectively reduced after intravenous administration of PVP-IO. Therefore PVP-IO nanoparticles are potentially useful for T2-weighted MR imaging. PMID:21394237

  20. Solution behavior of PVP-VA and HPMC-AS-based amorphous solid dispersions and their bioavailability implications.

    PubMed

    Qian, Feng; Wang, Jennifer; Hartley, Ruiling; Tao, Jing; Haddadin, Raja; Mathias, Neil; Hussain, Munir

    2012-10-01

    To identify the mechanism behind the unexpected bio-performance of two amorphous solid dispersions: BMS-A/PVP-VA and BMS-A/HPMC-AS. Solubility of crystalline BMS-A in PVP-VA and HPMC-AS was measured by DSC. Drug-polymer interaction parameters were obtained by Flory-Huggins model fitting. Drug dissolution kinetics of spray-dried dispersions were studied under sink and non-sink conditions. BMS-A supersaturation was studied in the presence of pre-dissolved PVP-VA and HPMC-AS. Potency and crystallinity of undissolved solid dispersions were determined by HPLC and DSC. Polymer dissolution kinetics were obtained by mass balance calculation. Bioavailability of solid dispersions was assessed in dogs. In solid state, both polymers are miscible with BMS-A, while PVP-VA solublizes the drug better. BMS-A dissolves similarly from both solid dispersions in vitro regardless of dissolution method, while the HPMC-AS dispersion performed much better in vivo. At the same concentration, HPMC-AS is more effective in prolonging BMS-A supersaturation; this effect was negated by the slow dissolution rate of HPMC-AS. Further study revealed that fast PVP-VA dissolution resulted in elevated drug loading in undissolved dispersions and facilitated drug recrystallization before complete release. In contrast, the hydrophobicity and slower HPMC-AS dissolution prevented BMS-A recrystallization within the HPMC-AS matrix for >24 h. The lower bioavailability of PVP-VA dispersion was attributed to BMS-A recrystallization within the undissolved dispersion, due to hydrophilicity and fast PVP-VA dissolution rate. Polymer selection for solid dispersion development has significant impact on in vivo performance besides physical stability.

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

    PubMed

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

    1986-08-01

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

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

    PubMed

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

    2014-10-01

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

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

    PubMed

    Glennon, Richard A; Young, Richard

    2016-09-01

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

  4. Raman and thermal analysis of indomethacin/PVP solid dispersion enteric microparticles.

    PubMed

    Fini, Adamo; Cavallari, Cristina; Ospitali, Francesca

    2008-09-01

    Indomethacin (IMC) and three types of poly-(vinylpyrrolidone) (PVP 12PF, PVP K30 and PVP K90) were studied in the form of solid dispersion, prepared with the solvent evaporation method, by spectroscopic (Raman, FT-IR, X-ray diffraction), thermal (differential scanning calorimetry, thermogravimetry, hot-stage microscopy), fractal and image analysis. Raman and FT-IR micro-spectroscopy indicated the occurrence of drug/polymer interaction and the presence of an amorphous form of IMC, as also resulting from X-ray diffractometry. Hot-stage microscopy suggested that the interaction between IMC and the polymer occurring on heating of a physical mixture, is common to other acidic compounds and causes a depression of the temperature of the appearance of a molten phase. Co-evaporated particles were coated by spray-congealing process with molten stearic acid for gastroprotection, but also for stabilization of the amorphous structure of the drug: the final particles were spherically shaped. Dissolution tests carried out on the final microparticles showed that the coating with stearic acid prevents IMC release at acidic pH and also protects against recovery of the IMC crystallinity, at least after 9 months of aging: the extent and mode of the release, before and after aging, overlap perfectly. The test revealed a notable improvement of the drug release rate from the solid dispersion at suitable pH, with respect to pure IMC. The comparison of the present solid dispersion with IMC/PVP (surface) solid dispersion obtained by freeze-drying of an aqueous suspension, where IMC maintained its crystalline state, revealed that there was no difference concerning the release rate, but suggested a superior quality of this last process as a mean of improving IMC availability for the easiness of preparation and stability, due to the absence of the amorphous state of the drug, as a possible instability source of the system. Finally, the coating with stearic acid is discussed as a determining

  5. 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.

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

    PubMed

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

    2014-06-01

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

  7. 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.

  8. 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.

  9. Structural Modification of the Designer Stimulant α-Pyrrolidinovalerophenone (α-PVP) Influences Potency at Dopamine Transporters.

    PubMed

    Kolanos, R; Sakloth, F; Jain, A D; Partilla, J S; Baumann, M H; Glennon, R A

    2015-10-21

    α-Pyrrolidinovalerophenone (α-PVP, 7) is an illegal synthetic stimulant that is being sold on the clandestine market as "flakka" and "gravel". The potent pharmacological effects of α-PVP are presumably mediated by inhibition of dopamine uptake at the dopamine transporter (DAT). However, little is known about how structural modification of α-PVP influences activity at DAT. Eleven analogs of α-PVP were synthesized and examined for their ability to inhibit uptake of [(3)H]dopamine and [(3)H]serotonin in rat brain synaptosomes. None of the analogs significantly inhibited [(3)H]serotonin uptake when tested at 10 μM at the serotonin transporter (SERT). All of the analogs behaved as DAT reuptake inhibitors, but potencies varied over a >1500-fold range. Potency was primarily associated with the nature of the α-substituent, with the more bulky substituents imparting the highest potency. Expansion of the pyrrolidine ring to a piperidine reduced potency up to 10-fold, whereas conformational constraint in the form of an aminotetralone resulted in the least potent compound. Our study provides the first systematic and comparative structure-activity investigation on the ability of α-PVP analogs to act as inhibitors of DAT.

  10. The use of PVP as a polymeric carrier to improve the plasma half-life of drugs.

    PubMed

    Kaneda, Yoshihisa; Tsutsumi, Yasuo; Yoshioka, Yasuo; Kamada, Haruhiko; Yamamoto, Yoko; Kodaira, Hiroshi; Tsunoda, Shin-ichi; Okamoto, Takayuki; Mukai, Yohei; Shibata, Hiroko; Nakagawa, Shinsaku; Mayumi, Tadanori

    2004-07-01

    To achieve an optimum drug delivery such as targeting or controlled release utilizing bioconjugation with polymeric modifier, the conjugate between drugs and polymeric modifiers must be designed to show desirable pharmacokinetic characteristics in vivo. In this study, we assessed the biopharmaceutical properties of various nonionic water-soluble polymers as polymeric drug carriers. Polyvinylpyrrolidone (PVP) showed the longest mean resident time (MRT) after i.v. injection of all nonionic polymers with the same molecular size. In fact, tumor necrosis factor-alpha (TNF-alpha) bioconjugated with PVP (PVP-TNF-alpha) circulated longer than TNF-alpha bioconjugated with polyethylene glycol (PEG-TNF-alpha) with the same molecular size. Each nonionic polymeric modifier showed a different tissue distribution. Dextran was accumulated in the spleen and liver. Polydimethylacrylamide (PDAAm) tended to distribute in the kidney. However, PVP showed the minimum volume of tissue distribution. These results suggested that PVP is the most suitable polymeric modifier for prolonging the circulation lifetime of a drug and localizing the conjugated drug in blood.

  11. 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

    2014-12-04

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

  12. 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.

  13. New recreational drug 1-phenyl-2-(1-pyrrolidinyl)-1-pentanone (alpha-PVP) activates central nervous system via dopaminergic neuron.

    PubMed

    Kaizaki, Asuka; Tanaka, Sachiko; Numazawa, Satoshi

    2014-02-01

    1-phenyl-2-(1-pyrrolidinyl)-1-pentanone (α-PVP) is a new designer drug of the cathinone type. People who have taken drugs containing α-PVP or other synthetic cathinone reportedly lose consciousness, develop difficulty breathing, and at worst case, die. However, the mechanism underlying α-PVP-induced neurotoxicity is unknown. The objective of the present study was to investigate the effect of α-PVP on the central nervous system (CNS) and compare its neurotoxicity with that of methamphetamine (METH) in mice. Balb/c male mice (8 weeks old) were orally administered α-PVP (25 mg/kg) or METH (5 mg/kg). α-PVP induced a significant increase in locomotor activity, which occurred earlier than locomotor activity induced by METH. This increase was inhibited by the D1 receptor antagonist SCH23990 (50 µg/kg, i.p.) and the D2 receptor antagonist sulpiride (50 mg/kg, i.m.). The extracellular concentration of dopamine (DA) in the striatum, determined by in vivo microdialysis increased immediately after α-PVP administration. These results suggest that α-PVP stimulates DA release, causing an increase in locomotor activity, and that this stimulatory effect of α-PVP on CNS is mediated, at least in part, by the D1 and D2 receptors.

  14. 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.

  15. 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.

  16. 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. Copyright © 2016 Elsevier B.V. All rights reserved.

  17. Optical Properties and Structure of Cobalt Chloride Doped Pva and its Blend with Pvp

    NASA Astrophysics Data System (ADS)

    Ahmed, R. M.

    2014-01-01

    Solution cast technique has been used to prepare films of PVA and its blend with PVP. Moreover, cobalt chloride (CoCl2) has been doped in PVA and also PVA/PVP 90/10 as a host matrix for it. Also, UV/VIS optical analysis has been used to drop more light on the structural modification that occurs due to doping CoCl2 with different levels in different polymeric matrixes. Indeed, UV-Vis spectra is a useful tool for studying the absorption spectra and estimating the values of absorption edge, Eg, and band tail, Eu, for all samples. The optical absorption measurements have been carried out in the wavelength region from 200 nm to 900 nm. In addition, the ligand field parameters and optical energy gaps have been calculated and discussed. X-ray diffraction (XRD) and fourier transform infrared (FTIR) spectroscopy have been used to characterize the studied samples which illustrates that PVA is strongly affected by mixed fillers.

  18. 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%.

  19. Stability of citrate, PVP, and PEG coated silver nanoparticles in ecotoxicology media.

    PubMed

    Tejamaya, Mila; Römer, Isabella; Merrifield, Ruth C; Lead, Jamie R

    2012-07-03

    Silver nanoparticles (AgNPs) are present in the environment and a number of ecotoxicology studies have shown that AgNPs might be highly toxic. Nevertheless, there are little data on their stability in toxicology media. This is an important issue as such dynamic changes affect exposure dose and the nature of the toxicant studied and have a direct impact on all (eco)toxicology data. In this study, monodisperse citrate, PVP, and PEG coated AgNPs with a core size of approximately 10 nm were synthesized and characterized; their behavior was examined in standard OECD media used for Daphnia sp. acute and chronic tests (in the absence of Daphnia). Surface plasmon resonance, size, aggregation, and shape were monitored over 21 days, comparable to a chronic exposure period. Charge stabilized particles (citrate) were more unstable than sterically stabilized particles. Replacement of chloride in the media (due to concerns over chloride-silver interactions) with either nitrate or sulfate resulted in increased shape and dissolution changes. PVP-stabilized NPs in a 10-fold diluted OECD media (chloride present) were found to be the most stable, with only small losses in total concentration over 21 days, and no shape, aggregation, or dissolution changes observed and are recommended for exposure studies.

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

    PubMed

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

    2014-04-01

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

  1. Development of diclofenac sodium-loaded alginate-PVP K 30 microbeads using central composite design.

    PubMed

    Nayak, Ak; Khatua, S; Hasnain, Ms; Sen, Kk

    2011-01-01

    Diclofenac sodium is a non-steroidal anti-inflammatory agent with a short biological half-life (1-2 hr) and requires multiple dosing. This research was carried out to develop and optimize diclofenac sodium loaded alginate-PVP K 30 microbeads to eliminate the need for multiple dosing and adverse effects. Diclofenac sodium loaded alginate-PVP K 30 microbeads were prepared by ionotropic gelation. Particle size, drug release, swelling, FTIR and SEM analyses were performed. Optimized microbeads showed particle size of 0.589±0.054 to 0.620±0.067 mm, and drug entrapment efficiency of 97.88±2.86 to 98.60±3.55%. The in vitro drug release from microbeads was sustained over 10 hrs and followed controlled-release pattern. FTIR analysis indicated the possibility of intermolecular hydrogen bonding interactions, i.e., -OH…O=C in microbeads. Microbeads for oral controlled delivery of diclofenac sodium were successfully developed by ionotropic gelation.

  2. 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.

  3. 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.

  4. 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.

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

    PubMed

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

    2017-02-15

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

  6. 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

  7. In vivo evaluation of chitosan-PVP-titanium dioxide nanocomposite as wound dressing material.

    PubMed

    Archana, D; Singh, Brijesh K; Dutta, Joydeep; Dutta, P K

    2013-06-05

    In our present study, the blends of chitosan, poly(N-vinylpyrrolidone) (PVP) and titanium dioxide (TiO2) were investigated by Fourier transform infrared (FTIR) spectroscopy and thermogravimetric analysis (TGA). The size distribution of the TiO2 nanoparticles was measured using transmission electron microscope and scanning electron microscope. The studies on the mechanical properties of composite material indicate that the addition of TiO2 nanoparticles increases its strength. The prepared nanocomposite dressing has excellent antimicrobial efficacy and good biocompatibility against NIH3T3 and L929 fibroblast cells. Compared to conventional gauze, soframycin skin ointment and chitosan treated groups, the prepared nano dressing caused an accelerated healing of open excision type wounds in albino rat model. The synergistic effects of nanocomposite dressing material like good antibacterial ability, high swelling properties, high WVTR, excellent hydrophilic nature, biocompatibility, wound appearance and wound closure rate through in vivo test makes it a suitable candidate for wound healing applications.

  8. 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.

  9. 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.

  10. 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.

  11. Studies on PVP hydrogel-supported luminol chemiluminescence: 1. Kinetic and mechanistic aspects using multivariate factorial analysis.

    PubMed

    Bastos, Erick Leite; Ciscato, Luiz Francisco Monteiro Leite; Bartoloni, Fernando Heering; Catalani, Luiz Henrique; Baader, Wilhelm Josef

    2007-01-01

    The chemiluminescent oxidation of luminol by hydrogen peroxide in the presence of hemin is revisited in an UV-C cross-linked PVP hydrogel. Chemiluminescence properties such as initial light intensity (I(0)), area of emission (S) and observed rate constants (k(obs)) are studied, varying the concentration of all reactants using a multivariate factorial approach.

  12. Synthesis and characterization of PVP/TbL(phen)0.5 x 7H2O nanorods.

    PubMed

    Cui, Zhenfeng; Ren, Huijuan; Sun, Dehui; Yang, Mei; Hong, Guangyan

    2011-11-01

    The luminescent complex terbium (III)-trimesic acid (TMA)-1,10-phenanthroline (phen) nanorod was synthesized in the polyvinylpyrrolidone (PVP) matrix by a co-precipitation method. The chemical formula of the synthesized complex was speculated to be PVP/TbL(phen)0.5 x 7H2O by inductively coupled plasma-atomic emission spectroscopy (ICP-AES), elemental analysis and Fourier-transform infrared spectroscopy (FTIR). The X-ray diffraction pattern (XRD) of PVP/TbL(phen)0.5 x 7H2O indicated that it was a crystalline complex. The transmission electron microscopy (TEM) result showed that the complex was nanorods with diameters of about 80-100 nm. The thermogravimetric curve (TGA) analysis exhibited that the complex has good stability below 400 degrees C. UV-Vis diffuse reflectance spectra showed that there is a maximum absorption at 300 nm. The photoluminescence analyses (PLA) showed that the synthesized complex emitted the characteristic green fluorescence of Tb (III) ions under ultraviolet light excitation. The emission peaks of PVP/TbL(phen)0.5 x 7H2O at 488, 542, 581, and 618 nm using 278 nm as exciting wavelength can be assigned to the 5D4 --> 7F6, 5D4 --> 7F5, 5D4 --> 7F4, and 5D4 --> 7F3 electron transitions of the Tb3+ ions, respectively.

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

    PubMed

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

    2014-01-06

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

  14. 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.

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

    PubMed Central

    2010-01-01

    Background Previous in vitro studies have demonstrated that polyvinylpyrrolidone coated silver nanoparticles (PVP-coated AgNPs) have antiviral activity against HIV-1 at non-cytotoxic concentrations. These particles also demonstrate broad spectrum virucidal activity by preventing the interaction of HIV-1 gp120 and cellular CD4, thereby inhibiting fusion or entry of the virus into the host cell. In this study, we evaluated the antiviral activity of PVP-coated AgNPs as a potential topical vaginal microbicide to prevent transmission of HIV-1 infection using human cervical culture, an in vitro model that simulates in vivo conditions. Results When formulated into a non-spermicidal gel (Replens) at a concentration of 0.15 mg/mL, PVP-coated AgNPs prevented the transmission of cell-associated HIV-1 and cell-free HIV-1 isolates. Importantly, PVP-coated AgNPs were not toxic to the explant, even when the cervical tissues were exposed continuously to 0.15 mg/mL of PVP-coated AgNPs for 48 h. Only 1 min of PVP-coated AgNPs pretreatment to the explant was required to prevent transmission of HIV-1. Pre-treatment of the cervical explant with 0.15 mg/mL PVP-coated AgNPs for 20 min followed by extensive washing prevented the transmission of HIV-1 in this model for 48 h. Conclusions A formulation of PVP-coated AgNPs homogenized in Replens gel acts rapidly to inhibit HIV-1 transmission after 1 min and offers long-lasting protection of the cervical tissue from infection for 48 h, with no evidence of cytotoxicity observed in the explants. Based on this data, PVP-coated AgNPs are a promising microbicidal candidate for use in topical vaginal/cervical agents to prevent HIV-1 transmission, and further research is warranted. PMID:20626911

  16. 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

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

    PubMed

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

    2017-01-03

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

  18. 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

  19. 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.

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

    SciTech Connect

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

    2016-05-23

    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 235 nm and 370 nm 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 320 nm.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.

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

    PubMed

    Sarkar, Sumit; Das, Ratan

    2017-10-05

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

  2. Impact of in situ preparation of CdS filled PVP nano-composite.

    PubMed

    Abdelghany, A M; Abdelrazek, E M; Rashad, D S

    2014-09-15

    Cadmium sulfide nanoparticles filled polyvinyl pyrrolidone (PVP) were prepared by in situ wet chemical precipitation technique. X-ray diffraction (XRD), Fourier transforms infrared spectra (FTIR), transmission electron microscopy (TEM) and ultraviolet-visible (UV/Vis) were used to characterize the prepared nano-composites. Density Function Theory (DFT) was used to approve the complexation process. XRD results indicate appearance of two peaks at about 28.1°, 27.4° corresponds to (101) and (002) planes which suggest hexagonal phase of CdS with lattice constants of 4.14, 6.72 Å in the polymeric matrix. UV/Vis spectra reveal that nano-composite films show quantum confinement effect. The absorption showed a shift toward the shorter wavelength (blue shift) with decrease in the concentration of Cd+ ions. Optical band gap and particle size were calculated and is in agreement with the results obtained from TEM data. Transmission electron microscopy shows that the prepared CdS nanoparticles were dispersed and nearly uniform in diameter within the polymeric matrix.

  3. Fabrication of cobalt nanocrystals by rapid pyrolysis in inverse PS-PVP micelles and thermal annealing

    NASA Astrophysics Data System (ADS)

    Diana, Frederic S.; Lee, Seung-Heon; Segalman, Rachel A.; Petroff, Pierre M.; Kramer, Edward J.

    2003-03-01

    Magnetic colloidal nanocrystals aggregate in solution due to magnetic dipolar interactions, which lead to poor processing ability. A diblock copolymer was used in order to better control the interparticle separation, and crystallization of the micelle cores was performed after deposition onto substrates to limit the effects of magnetic interactions. Cobalt nanoparticles have been synthesized within inverse micelles of polystyrene-poly(2-vinylpyridine) (PS-PVP) diblock copolymer in toluene by the pyrolysis of dicobalt octacarbonyl at 115^oC. The nanoparticle structure at different reaction times was investigated using transmission electron microscopy (TEM), scanning electron microscopy (SEM) and atomic force microscopy (AFM). At the early stages of reaction, the nanoparticles were found to be amorphous, and FT-IR showed that the precursor was partially decomposed. The ones after 15 min of reaction were crystalline forming chains due to the magnetic interactions, and the precursor was fully decomposed. The amorphous nanoparticles were crystallized after their transfer onto substrates on heating to above 350°C to produce nearly monodisperse single-nanocrystals inside each micelle, but such annealing leads to degradation of the polymer.

  4. Cyclodextrin modified hydrogels of PVP/PEG for sustained drug release.

    PubMed

    Nielsen, Anne Louise; Madsen, Flemming; Larsen, Kim Lambertsen

    2009-02-01

    Hydrogels are water swollen networks of polymers and especially hydrogels consisting of poly vinylpyrrolidone/poly ethyleneglycol-dimethacrylate (PVP/PEG-DMA) blends show promising wound care properties. Enhanced functionality of the hydrogels can be achieved by incorporating drugs and other substances that may assist wound healing into the gel matrix. Controlling the release of active compounds from the hydrogels may be possible by carefully modifying the polymer matrix. For this purpose, cyclodextrins (CD) were grafted to the polymer matrix in 4-5 w/w% in an attempt to retard the release of water-soluble drugs. Ibuprofenate (IBU) was chosen as model drug and loaded in IBU/CD ratios of 0.6, 1.2, and 2.5. Vinyl derivatives of alpha-, beta- and gamma-CD were produced, added to the prepolymer blend and cured by UV-light. During this curing process the CD derivatives were covalently incorporated into the hydrogel matrix. The modified hydrogels were loaded with ibuprofenate by swelling. The release of the model drug from CD modified hydrogels show that especially covalently bonded beta-cyclodextrin can change both the release rate and the release profile of ibuprofen.

  5. Phase characterization of indomethacin in binary solid dispersions with PVP VA64 or Myrj 52.

    PubMed

    Wang, Xin; de Armas, Hector Novoa; Blaton, Norbert; Michoel, Armand; Van den Mooter, Guy

    2007-12-10

    In the present study the properties of binary solid dispersions made up of PVP VA64, Myrj 52 and indomethacin (IMC) are studied and characterized. The solid dispersions were prepared by dissolving the materials in dichloromethane, followed by solvent evaporation under reduced pressure at 55 degrees C in a rotavapor. Binary solid dispersions were characterized by standard and modulated temperature differential scanning calorimetry (MTDSC), thermogravimetry (TGA) and X-ray powder diffraction (XRPD). XRPD analysis showed that the initial IMC was in its gamma-form, and that it was transformed to the beta-form (reported to be a solvate) together with an amorphous fraction in the solid dispersions. A mixture of the beta-form and amorphous IMC was also obtained in the binary systems containing less than 30% polymer. IMC without adding polymer was subjected to the same experimental procedures as in the solid dispersions, and used as a model to characterize the solid-state transformations. The following order of transitions was observed: from the initial gamma-form, the beta-form was obtained together with an amorphous component, then the crystalline beta-form transforms into the alpha-form which melts and recrystallizes into the most stable gamma-form.

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

    NASA Astrophysics Data System (ADS)

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

    2016-12-01

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

  7. Immobilisation of Fenugreek β-amylase on chitosan/PVP blend and chitosan coated PVC beads: a comparative study.

    PubMed

    Srivastava, Garima; Roy, Sonam; Kayastha, Arvind M

    2015-04-01

    A Box-Behnken design of Response Surface Methodology (RSM) was utilised for optimisation of parameters affecting immobilisation of Fenugreek β-amylase on chitosan coated PVC (polyvinyl chloride) beads and beads made from chitosan/PVP (polyvinylpyrrolidone) blend, which resulted in 85.2% and 81% immobilisation efficiency, respectively. Immobilisation resulted in shift of pH optima while the optimum temperature remained unaffected. Enhancement in thermal stability of the enzyme was observed on conjugation with both the matrices. The immobilised enzyme appeared suitable for industrial applications due to the non-toxic nature of chosen matrices, ease of immobilisation procedure, enhanced stability and reusability with retention of 72% and 60% residual activity after 10 uses for the enzyme immobilised on chitosan coated PVC beads and on the beads of chitosan/PVP blend, respectively. Copyright © 2014 Elsevier Ltd. All rights reserved.

  8. 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.

  9. 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.

  10. 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.

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

    PubMed

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

    2017-10-05

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

  12. The effect of coumarin on protein and PVP clearance from rat legs with various high protein oedemas.

    PubMed Central

    Piller, N. B.; Casley-Smith, J. R.

    1975-01-01

    Coumarin (a benzo-pyrone) has been shown to bring about the rapid removal of protein from normal or burnt tissues and from those with lymphoedema, with or without burning. This was particularly evident when the removal of protein was compared with that of a non-metabolizable control-PVP. The mode of action would seem to be by stimulation of proteolysis. The fragments of protein could then rapidly leave the tissues because of their small size, their high diffusion coefficients and a concentration gradient which was directed from the tissues to the blood. In this way excessive amounts of protein would be removed, thus releasing the oedema fluid. The removal of non-metabolizable PVP was reduced with normal and burnt legs, possibly of stimulated phagocytosis. In the presence of lymphoedema there was a more rapid removal of PVP with coumarin; this was possibly a consequence of the great reduction of intercapillary distances resulting from the removal of oedema fluid. PMID:1212425

  13. Effect of PVP as a capping agent in single reaction synthesis of nanocomposite soft/hard ferrite nanoparticles

    NASA Astrophysics Data System (ADS)

    Ahmad, H. A.; Saiden, N. M.; Saion, E.; Azis, R. S.; Mamat, M. S.; Hashim, M.

    2017-04-01

    Nanocomposite magnets consist of soft and hard ferrite phases are known as an exchange spring magnet when they are sufficiently spin exchange coupled. Hard and soft ferrites offer high value of coercivity, Hc and saturation magnetization, Ms respectively. In order to obtain a better permanent magnet, both soft and hard ferrite phases need to be ;exchange coupled;. The nanoparticles were prepared by a simple one-pot technique of 80% soft phase and 20% hard phase. This technique involves a single reaction mixture of metal nitrates and aqueous solution of varied amounts of polyvinylpyrrolidone (PVP). The heat treatment applied was at 800 °C for 3 h. The synthesized composites were characterized by Transmission Electron Microscope (TEM), Fourier Transform Infra-red (FT-IR), Energy Dispersive X-Ray (EDX), X-ray diffraction (XRD) and Vibrating sample magnetometer (VSM). The coexistence of two phases, Ni0.5Zn0.5Fe2O4 and SrFe12O19 were observed by XRD patterns. It also verified by the EDX that no impurities detected. The magnetic properties of nanocomposite ferrites for 0.06 g/ml PVP gives a better properties of Hc 932 G and Ms 39.0 emu/g with average particle size obtained from FESEM was 49.2 nm. The concentration of PVP used gives effect on the magnetic properties of the samples.

  14. Prediction of thermal conductivity of polyvinylpyrrolidone (PVP) electrospun nanocomposite fibers using artificial neural network and prey-predator algorithm.

    PubMed

    Khan, Waseem S; Hamadneh, Nawaf N; Khan, Waqar A

    2017-01-01

    In this study, multilayer perception neural network (MLPNN) was employed to predict thermal conductivity of PVP electrospun nanocomposite fibers with multiwalled carbon nanotubes (MWCNTs) and Nickel Zinc ferrites [(Ni0.6Zn0.4) Fe2O4]. This is the second attempt on the application of MLPNN with prey predator algorithm for the prediction of thermal conductivity of PVP electrospun nanocomposite fibers. The prey predator algorithm was used to train the neural networks to find the best models. The best models have the minimal of sum squared error between the experimental testing data and the corresponding models results. The minimal error was found to be 0.0028 for MWCNTs model and 0.00199 for Ni-Zn ferrites model. The predicted artificial neural networks (ANNs) responses were analyzed statistically using z-test, correlation coefficient, and the error functions for both inclusions. The predicted ANN responses for PVP electrospun nanocomposite fibers were compared with the experimental data and were found in good agreement.

  15. A cost-minimisation analysis comparing photoselective vaporisation (PVP) and transurethral resection of the prostate (TURP) for the management of symptomatic benign prostatic hyperplasia (BPH) in Queensland, Australia.

    PubMed

    Whitty, Jennifer A; Crosland, Paul; Hewson, Kaye; Narula, Rajan; Nathan, Timothy R; Campbell, Peter A; Keller, Andrew; Scuffham, Paul A

    2014-03-01

    To compare the costs of photoselective vaporisation (PVP) and transurethral resection of the prostate (TURP) for management of symptomatic benign prostatic hyperplasia (BPH) from the perspective of a Queensland public hospital provider. A decision-analytic model was used to compare the costs of PVP and TURP. Cost inputs were sourced from an audit of patients undergoing PVP or TURP across three hospitals. The probability of re-intervention was obtained from secondary literature sources. Probabilistic and multi-way sensitivity analyses were used to account for uncertainty and test the impact of varying key assumptions. In the base case analysis, which included equipment, training and re-intervention costs, PVP was AU$ 739 (95% credible interval [CrI] -12 187 to 14 516) more costly per patient than TURP. The estimate was most sensitive to changes in procedural costs, fibre costs and the probability of re-intervention. Sensitivity analyses based on data from the most favourable site or excluding equipment and training costs reduced the point estimate to favour PVP (incremental cost AU$ -684, 95% CrI -8319 to 5796 and AU$ -100, 95% CrI -13 026 to 13 678, respectively). However, CrIs were wide for all analyses. In this cost minimisation analysis, there was no significant cost difference between PVP and TURP, after accounting for equipment, training and re-intervention costs. However, PVP was associated with a shorter length of stay and lower procedural costs during audit, indicating PVP potentially provides comparatively good value for money once the technology is established. © 2013 The Authors. BJU International © 2013 BJU International.

  16. Poly-4-vinylphenol (PVP) and Poly(melamine-co-formaldehyde) (PMF)-Based Atomic Switching Device and Its Application to Logic Gate Circuits with Low Operating Voltage.

    PubMed

    Kang, Dong-Ho; Choi, Woo-Young; Woo, Hyunsuk; Jang, Sungkyu; Park, Hyung-Youl; Shim, Jaewoo; Choi, Jae-Woong; Kim, Sungho; Jeon, Sanghun; Lee, Sungjoo; Park, Jin-Hong

    2017-08-16

    In this study, we demonstrate a high-performance solid polymer electrolyte (SPE) atomic switching device with low SET/RESET voltages (0.25 and -0.5 V, respectively), high on/off-current ratio (10(5)), excellent cyclic endurance (>10(3)), and long retention time (>10(4) s), where poly-4-vinylphenol (PVP)/poly(melamine-co-formaldehyde) (PMF) is used as an SPE layer. To accomplish these excellent device performance parameters, we reduce the off-current level of the PVP/PMF atomic switching device by improving the electrical insulating property of the PVP/PMF electrolyte through adjustment of the number of cross-linked chains. We then apply a titanium buffer layer to the PVP/PMF switching device for further improvement of bipolar switching behavior and device stability. In addition, we first implement SPE atomic switch-based logic AND and OR circuits with low operating voltages below 2 V by integrating 5 × 5 arrays of PVP/PMF switching devices on the flexible substrate. In particular, this low operating voltage of our logic circuits was much lower than that (>5 V) of the circuits configured by polymer resistive random access memory. This research successfully presents the feasibility of PVP/PMF atomic switches for flexible integrated circuits for next-generation electronic applications.

  17. 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.

  18. 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. Copyright © 2016 Elsevier B.V. All rights reserved.

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

    PubMed

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

    2017-09-01

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

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

    PubMed

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

    2017-03-21

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

  1. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2017-06-01

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

  3. [Do polyvinylpyrrolidone (PVP) deposits still occur in internal organs at the turn of the millennium? Observations on three patients from the former USSR].

    PubMed

    Mohr, W; Endres-Klein, R

    2002-09-01

    PVP had been used as a plasma expander following the end of world war II up to relatively recently but after its intracellular storage became known, it was withdrawn from use. Nevertheless, it was used as a retarding agent for subcutaneous and intramuscular administration of drugs until the 1980s and as a consequence pseudotumors have been observed. Three patients from the former USSR are described with PVP storage in the gastric and duodenal mucosa as well as in lymph nodes. The reason for the administration in these patients and the substances applied remain obscure. It is known that PVP infusions are still performed in Taiwan and that it was also injected intraarticularly as an artificial joint lubricant in Russia in the early 1990s. Because cells with intracytoplasmic deposits of PVP can be misdiagnosed as tumor cells and for reasons of general health - "la maladie polyvinylique" [1] may develop - it is still necessary to retain knowledge of the histology of cellular PVP storage.

  4. 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

    2015-10-29

    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.

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

    PubMed

    Li, Wanjing; Buckton, Graham

    2015-11-30

    The purpose of this work was to investigate the distribution of water in a physically unstable amorphous solid dispersion (polyvinylpyrrolidone (PVP) and griseofulvin (as a model hydrophobic drug)), both as the sample absorbs water and during prolonged exposure to elevated humidity by use of dynamic vapour sorption combined with near infrared (DVS-NIR). The solid dispersion absorbed much less water than the sum of the water sorption of the individual components. This suggests that griseofulvin hindered PVP from absorbing water through the formation of the solid dispersion. Prolonged storage of the solid dispersion at 75% RH resulted in no significant mass change. Whilst this would usually be interpreted as the absence of crystallization, the NIR spectra demonstrated that crystallization occurred. The reason for the lack of a weight loss was that the expelled water from amorphous griseofulvin was sorbed by PVP, meaning that as the dispersion was broken by the crystallisation of griseofulvin, the PVP was once again free to sorb water (in line with the higher water sorption shown by PVP alone, and in contrast with the lower sorption of water by the solid dispersion). As water is a key factor in the physical stability of amorphous systems, understanding how and where water is absorbed and how this is liable to change is an important advance and offers promise in understanding the mechanism of stabilisation of solid dispersions, and therefore may be useful to predict the stability of new API dispersions. Copyright © 2015 Elsevier B.V. All rights reserved.

  6. 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

  7. Preparation of lutein-loaded particles for improving solubility and stability by Polyvinylpyrrolidone (PVP) as an emulsion-stabilizer.

    PubMed

    Zhao, Changdong; Cheng, Hui; Jiang, Pengfei; Yao, Yijing; Han, Jing

    2014-08-01

    Lutein, a non-provitamin A carotenoid, possesses multiple valuable physiological functions. Unfortunately, its application is limited due to its poor water solubility and instability under adverse conditions. To expand the applied range of lutein, we developed lutein-loaded particles and characterized by differential scanning calorimetry, X-ray powder diffraction and Fourier transformed infrared spectroscopy and investigated the encapsulation efficiency, aqueous saturation solubility and stability. The results showed that the lutein-loaded particles possessed high encapsulation efficiency (93.8±0.35%) and good water solubility (158μg/ml). Compared with free lutein, the stability of the lutein-loaded particles against heat, light and oxygen was improved by 1.7 times, 3.3 times and 4.0 times, respectively. The results also indicated that lutein was embedded in PVP matrix in an amorphous state, and intermolecular hydrogen bonding was in existence between PVP, lutein and Tween 80, forming the main force assembling the lutein-loaded particles. Copyright © 2014 Elsevier Ltd. All rights reserved.

  8. Spectroscopic investigations and electrical properties of PVA/PVP blend filled with different concentrations of nickel chloride

    NASA Astrophysics Data System (ADS)

    Ragab, H. M.

    2011-10-01

    Films of PVA/PVP blend (50/50) filled with different concentrations of NiCl 2 were prepared by casting method. The prepared films were investigated by different techniques. XRD scans demonstrated that the peak intensity at 2 θ≈20° decreased and the band width increased with increase in the concentrations of NiCl 2 content, which implied decrease in the degree of crystallization and hence causes increase in the amorphous region. UV-vis analysis revealed that the values of the optical band gap are affected with increase in NiCl 2 content. This indicates the formation of charge transfer complexes between the polymer blend and the filler. The rise of conductivity is significant with increased concentration of NiCl 2 filler; this reveals an increase in degree of amorphosity. AC conductivity ( σac) behavior of all the prepared films was investigated over the frequency range 42 Hz-5 MHz and under different isothermal stabilization in the temperature range 313-393 K. It suggests that the hopping mechanism might be playing an important role in the conduction process in high frequency region. The dielectric behavior was analyzed using dielectric permittivity ( ε´, ε″) dielectric loss tangent (tan δ) and electric modulus ( M″). The decrease in dielectric permittivity was observed with increase in the concentration of NiCl 2 filler. This suggests the role of NiCl 2 as filler to improve the electrical conductivity of PVA/PVP blend.

  9. Facile Electrospinning Synthesis of Carbonized Polyvinylpyrrolidone (PVP)/g-C3 N4 Hybrid Films for Photoelectrochemical Applications.

    PubMed

    Wang, Yan; Zhao, Xu; Tian, Yang; Wang, Yanbin; Jan, Abdul Khaliq; Chen, Yutong

    2017-01-05

    The film-forming ability and conductivity of graphitic carbon nitride (g-C3 N4 ) are still unsatisfying, despite much progress having been made in g-C3 N4 -related photocatalysts. New methods for synthesizing g-C3 N4 films coupled with excellent conductive materials are of significance. Herein, a facile method for synthesizing novel carbonized polyvinylpyrrolidone (PVP)/g-C3 N4 (CPVP /g-C3 N4 ) films have been developed through an electrospinning technique. Nanocarbons are generated by in situ carbonization of PVP in the films, which could enhance the photoelectrochemical (PEC) performance of the films due to its good conductivity. The coverage of the CPVP /g-C3 N4 film is good and the films exhibit excellent PEC performance. Furthermore, the thickness of the films can be adjusted by varying the electrospinning time and substantially controlling the PEC performance, of which the photocurrent densities under visible-light irradiation are 3.55, 4.92, and 6.64 μA cm(-2) with spinning times of 40, 70, and 120 min, respectively. The photocurrent does not decrease until testing at 4000 s and the coverage is still good after the tests, which indicates the good stability of the films. The excellent PEC performance of the films and facile preparation method enables promising applications in energy and environmental remediation areas. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. Preparation and characterization of poly(AA co PVP)/PGS composite and its application for methylene blue adsorption.

    PubMed

    Yang, Cai-xia; Lei, Lei; Zhou, Peng-xin; Zhang, Zhe; Lei, Zi-qiang

    2015-04-01

    Poly (AA co PVP)/PGS (PAPP) composite adsorbent was prepared by radical polymerization from Acrylic acid (AA), Polyvinylpyrrolidone (PVP) and Palygorskite (PGS), using N,N-methylenebisacrylamide (MBA) as cross-linker and potassium persulfate (KPS) as initiator. The PAPP was characterized with Fourier transform infrared (FT-IR), thermogravimetric analysis (TG), scanning electron microscope (SEM) and transmission electron microscopy (TEM). PAPP was used as adsorbent for the removal of methylene blue from aqueous solutions. The influences of pH, adsorption temperature and adsorption time on the adsorption properties of the composite to the dye were also investigated. Meanwhile, the adsorption rate data and adsorption equilibrium date were analyzed based on the pseudo-first-order and pseudo-second-order kinetic model, Langmuir and Freundlich isotherm models, respectively. The results indicating that the kinetic behavior better fit with the pseudo-second-order kinetic model. The maximum equilibrium adsorption capacity (q(m)) is 1815 mg/g at 289 K. The isotherm behavior can be explained by the Langmuir isotherm models. The activation energy was also evaluated for the removal of methylene blue onto PAPP. These results demonstrate that this composite material could be used as a good adsorbent for the removal of cationic dyes from wastewater.

  11. 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.

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

    SciTech Connect

    Dyartanti, Endah R. E-mail: endah-rd@uns.ac.id; Purwanto, Agus; Widiasa, I. Nyoman; Susanto, Heru E-mail: endah-rd@uns.ac.id

    2016-02-08

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

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

    PubMed

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

    2011-05-01

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

  14. Holmium laser enucleation (HoLEP) and photoselective vaporisation of the prostate (PVP) for patients with benign prostatic hyperplasia (BPH) and chronic urinary retention.

    PubMed

    Jaeger, Christopher D; Mitchell, Christopher R; Mynderse, Lance A; Krambeck, Amy E

    2015-02-01

    To evaluate short-term outcomes of holmium laser enucleation of the prostate (HoLEP) and photoselective vaporisation of the prostate (PVP) in patients with benign prostatic hyperplasia (BPH) and chronic urinary retention (CUR). A retrospective chart review was performed of all patients with CUR who underwent HoLEP or PVP at our institution over a 3-year period. CUR was defined as a persistent post-void residual urine volume (PVR) of >300 mL or refractory urinary retention requiring catheterisation. We identified 72 patients with CUR who underwent HoLEP and 31 who underwent PVP. Preoperative parameters including median catheterisation duration (3 vs 5 months, P = 0.71), American Urological Association Symptom Index score (AUASI; 18 vs 21, P = 0.24), and PVR (555 vs 473 mL, P = 0.096) were similar between the HoLEP and PVP groups. The HoLEP group had a larger prostate volume (88.5 vs 49 mL, P < 0.001) and higher PSA concentration (4.5 vs 2.4 ng/mL, P = 0.001). At median 6-month follow-up, 71 (99%) HoLEP patients and 23 (74%) PVP patients were catheter-free (P < 0.001). Of the voiding patients, postoperative AUASI (3 vs 4, P = 0.06), maximum urinary flow rate (23 vs 18 mL/s, P = 0.28) and PVR (56.5 vs 54 mL, P = 1.0) were improved in both groups. Both HoLEP and PVP are effective at improving urinary parameters in men with CUR. Despite larger prostate volumes, HoLEP had a 99% successful deobstruction rate, thus rendering patients catheter-free. © 2014 The Authors. BJU International © 2014 BJU International.

  15. 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

  16. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2017-04-01

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

  18. Transport of industrial PVP-stabilized silver nanoparticles in saturated quartz sand coated with Pseudomonas aeruginosa PAO1 biofilm of variable age.

    PubMed

    Mitzel, Michael R; Tufenkji, Nathalie

    2014-01-01

    Understanding the environmental fate and transport of engineered nanoparticles (ENPs) is of paramount importance for the formation and validation of regulatory guidelines regarding these new and increasingly prevalent materials. The present study assessed the transport of an industrial formulation of poly(vinylpyrrolidone)-stabilized silver nanoparticle (PVP-nAg) in columns packed with water-saturated quartz sand and the same sand coated with Pseudomonas aeruginosa PAO1 biofilm of variable age (i.e., growth period). Physicochemical characterization studies indicate that the PVP-nAg is stable in suspension and exhibits little change in size or electrophoretic mobility with changing ionic strength (IS) in either NaNO3 or Ca(NO3)2. The collector surface had a relatively homogeneous biofilm coating, as determined by CLSM, and a near uniform distribution of biomass and biofilm thickness following column equilibration. Transport experiments in clean sand revealed changes in the particle deposition behavior only at and above 10 mM IS Ca(NO3)2 and showed no discernible change in PVP-nAg transport behavior in the presence of 1 to 100 mM NaNO3. Transport experiments in P. aeruginosa-coated sand indicated significantly reduced retention of PVP-nAg at low IS compared to clean sand, irrespective of biofilm age. Nanoparticle retention was also generally reduced in the biofilm-coated sand at the higher IS, but to a lesser extent. The decreased retention of PVP-nAg in biofilm-coated sand compared to clean sand is likely due to repulsive electrosteric forces between the PVP coatings and extracellular polymeric substances (EPS) of the biofilm. Additionally, the slope of the rising portion of the PVP-nAg breakthrough curve was noticeably steeper in biofilm conditions than in clean sand. More mature biofilm coating also resulted in earlier breakthrough of PVP-nAg compared to younger biofilm coatings, or to the clean sand, which may be an indication of the effect of repulsive surface

  19. Does prostate configuration affect the efficacy and safety of GreenLight HPS™ laser photoselective vaporization prostatectomy (PVP)?

    PubMed

    Gu, Xiao; Strom, Kurt; Spaliviero, Massimiliano; Wong, Carson

    2013-02-01

    We evaluate the efficacy and safety of GreenLight HPS™ laser photoselective vaporization prostatectomy (PVP) for the treatment of benign prostatic hyperplasia (BPH) with different prostate configuration. Patients were stratified into two groups: bilobe (group I) and trilobe (group II) BPH. Transurethral PVP was performed using a 120 W GreenLight HPS™ side-firing laser system. American Urological Association Symptom Score (AUASS), Quality of Life (QoL) score, maximum flow rate (Q max), and postvoid residual (PVR) were measured preoperatively and at 1 and 4 weeks and 3, 6, 12, 18, 24 and 36 months postoperatively. A number of 160 consecutive patients were identified (I: 86, II: 74). Among the preoperative parameters, there were significant differences (p < 0.05) in prostate volume (I: 46.0 ± 19.8; II: 87.5 ± 39.6 ml), Q max (I: 9.9 ± 3.9; II: 8.7 ± 3.5 ml/sec), PVR (I: 59.2 ± 124.6; II: 97.7 ± 119.1 ml) and PSA (I: 1.4 ± 1.4; II: 3.6 ± 2.6 ng/ml), while AUASS and QoL were similar (p > 0.05). Significant differences (p < 0.05) in laser utilization (I: 9.5 ± 6.6; II: 19.5 ± 11.6 min) and energy usage (I: 63.1 ± 43.9; II: 132.5 ± 81.1 kJ) were noted. Clinical outcomes (AUASS, QoL, Q max, and PVR) showed immediate and stable improvement from baseline (p < 0.05) within each group, but no significant differences between the two groups were observed during the follow-up period (p > 0.05). The incidences of adverse events were low and similar in both groups. Our experience suggests that BPH configuration has little effect on the efficacy and safety of GreenLight HPS™ laser PVP.

  20. 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.

  1. Determination of total polyvinylpyrrolidone (PVP) in ophthalmic solutions by size exclusion chromatography with ultraviolet-visible detection.

    PubMed

    Tavlarakis, Panagiotis; Urban, John J; Snow, Nicholas

    2011-01-01

    A straightforward size exclusion chromatography (SEC) method was developed and validated for the determination of total polivinylpyrrolidone (PVP) in ophthalmic solutions using the unusual combination of size exclusion chromatography (SEC), ultraviolet-visible detection and quantitation of an analyte peak that elutes in the total exclusion volume of the column. Samples of opthalmic solutions are diluted with water and injected onto a TSKgel G1000PW, 7.5 mm i.d. × 30 cm, 12 μm column at 50°C, with 80:20 0.1M sodium acetate-methanol mobile phase and UV detection at 220 nm. Validation was successful for a stability indicating pharmaceutical method, with parameters including specificity, accuracy, linearity, and precision within typical pharmaceutical acceptance criteria. A stress study with acid, base, peroxide, heat, and light indicates that there is no interference from drug, product, or excipients.

  2. 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.

  3. 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

    2017-07-01

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

  4. 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.

  5. 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.

  6. Influence of Polymer Molecular Weight on Drug-Polymer Solubility: A Comparison between Experimentally Determined Solubility in PVP and Prediction Derived from Solubility in Monomer.

    PubMed

    Knopp, Matthias Manne; Olesen, Niels Erik; Holm, Per; Langguth, Peter; Holm, René; Rades, Thomas

    2015-09-01

    In this study, the influence of polymer molecular weight on drug-polymer solubility was investigated using binary systems containing indomethacin (IMC) and polyvinylpyrrolidone (PVP) of different molecular weights. The experimental solubility in PVP, measured using a differential scanning calorimetry annealing method, was compared with the solubility calculated from the solubility of the drug in the liquid analogue N-vinylpyrrolidone (NVP). The experimental solubility of IMC in the low-molecular-weight PVP K12 was not significantly different from that in the higher molecular weight PVPs (K25, K30, and K90). The calculated solubilities derived from the solubility in NVP (0.31-0.32 g/g) were found to be lower than those experimentally determined in PVP (0.38-0.40 g/g). Nevertheless, the similarity between the values indicates that the analogue solubility can provide valuable indications on the solubility in the polymer. Hence, if a drug is soluble in an analogue of the polymer, it is most likely also soluble in the polymer. In conclusion, the solubility of a given drug-polymer system is determined by the strength of the drug-polymer interactions rather than the molecular weight of the polymer. Therefore, during the first screenings for drug solubility in polymers, only one representative molecular weight per polymer is needed.

  7. 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.

  8. 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.

  9. New designer drug alpha-pyrrolidinovalerophenone (PVP): studies on its metabolism and toxicological detection in rat urine using gas chromatographic/mass spectrometric techniques.

    PubMed

    Sauer, Christoph; Peters, Frank T; Haas, Claudia; Meyer, Markus R; Fritschi, Giselher; Maurer, Hans H

    2009-06-01

    The aim of the present study was to identify the metabolites of the new designer drug alpha-pyrrolidinovalerophenone (PVP) in rat urine using GC/MS techniques. Eleven metabolites of PVP could be identified suggesting the following metabolic steps: hydroxylation of the side chain followed by dehydrogenation to the corresponding ketone; hydroxylation of the 2''-position of the pyrrolidine ring followed by dehydrogenation to the corresponding lactam or followed by ring opening to the respective aliphatic aldehyde and further oxidation to the respective carboxylic acid; degradation of the pyrrolidine ring to the corresponding primary amine; and hydroxylation of the phenyl ring, most probably in the 4'-position. The authors' screening procedure for pyrrolidinophenones allowed the detection of PVP metabolites after application of a dose corresponding to a presumed user's dose. In addition, the involvement of nine different human cytochrome P450 (CYP) isoenzymes in the side chain hydroxylation of PVP was investigated and CYP 2B6, 2C19, 2D6, and 3A4 were found to catalyze this reaction.

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

    SciTech Connect

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

    2016-03-01

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

  11. 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.

  12. 4-Methoxy-α-PVP: in silico prediction, metabolic stability, and metabolite identification by human hepatocyte incubation and high-resolution mass spectrometry.

    PubMed

    Ellefsen, Kayla N; Wohlfarth, Ariane; Swortwood, Madeleine J; Diao, Xingxing; Concheiro, Marta; Huestis, Marilyn A

    Novel psychoactive substances are continuously developed to circumvent legislative and regulatory efforts. A new synthetic cathinone, 4-methoxy-α-PVP, was identified for the first time in illegal products; however, the metabolism of this compound is not known. Complete metabolic profiles are needed for these novel psychoactive substances to enable identification of their intake and to link adverse effects to the causative agent. This study assessed 4-methoxy-α-PVP metabolic stability with human liver microsomes (HLMs) and identified its metabolites after HLM and hepatocyte incubations followed by high-resolution mass spectrometry (HRMS). A Thermo QExactive high-resolution mass spectrometer (HRMS) was used with full scan data-dependent mass spectrometry, with (1) and without (2) an inclusion list of predicted metabolite, and with full scan and all-ion fragmentation (3) to identify potential unexpected metabolites. In silico predictions were performed and compared to in vitro results. Scans were thoroughly mined with different data processing algorithms using WebMetabase (Molecular Discovery). 4-Methoxy-α-PVP exhibited a long half-life of 79.7 min in HLM, with an intrinsic clearance of 8.7 µL min(-1) mg(-1). In addition, this compound is predicted to be a low-clearance drug with an estimated human hepatic clearance of 8.2 mL min(-1) kg(-1). Eleven 4-methoxy-α-PVP metabolites were identified, generated by O-demethylation, hydroxylation, oxidation, ketone reduction, N-dealkylation, and glucuronidation. The most dominant metabolite in HLM and human hepatocyte samples was 4-hydroxy-α-PVP, also predicted as the #1 in silico metabolite, and is suggested to be a suitable analytical target in addition to the parent compound.

  13. PVP stabilized Pt nano particles catalyzed de-oxygenation of phenoxazine group by hydrazine in physiological buffer media: surfactant competes with reactants for the same surface sites.

    PubMed

    Das, Ranendu Sekhar; Singh, Bula; Banerjee, Rupendranath; Mukhopadhyay, Subrata

    2013-03-21

    PVP capped platinum nano particles (PNP) of 5 nm diameter were prepared and characterized as homogeneous and of spherical nature. At physiological pH range (6.0-8.0), these PNP catalyze the deoxygenation of phenoxazine group containing resazurin (1) by hydrazine. The observed rate constants (k(o)), increase linearly with [PNP] at constant [1] and [Hydrazine]; but first increase and then after reaching a maximum it decrease with increase in [1] as well as in [Hydrazine]. The k(o) values increase linearly with 1/[H(+)] indicating N(2)H(4) as the reducing species that generates from the PNP assisted deprotonation of N(2)H(5)(+). The kinetic observations suggest Langmuir-Hinshelwood type surface reaction mechanism where both 1 and hydrazine are adsorbed on nano particles surface and compete for the same sites. Interestingly, the surfactant molecules, polyvinylpyrrolidone (PVP), though do not take part into reduction reaction but having same type of functional groups as reactants, competes with them for the same surface sites. Adsorption on PNP with same type of functional group is further supported by the FTIR spectra of Pt-PVP and Pt-1. Thus on increasing [PVP], k(o) decreases linearly and only when [PVP] is held constant, the plot of k(o) vs. [PNP] passes through the origin indicating the insignificance of uncatalyzed reaction. The plot of ln k(o) vs. [1] or [Hydrazine] shows two different linear zones with different exponent values with respect to [1] and [Hydrazine]. This indicates that along with the complex heterogeneous surface adsorption processes, the mutual interactions between the reactants are also changing with the relative concentrations of reactants or, in general, with the molar ratio ([Hydrazine]/[1]).

  14. Extraction of human DNA for PCR from chewed residues of betel quid using a novel "PVP/CTAB" method.

    PubMed

    Chiou, F S; Pai, C Y; Hsu, Y P; Tsai, C W; Yang, C H

    2001-09-01

    Residues of chewed betel quid (BQ) are often found on crime scenes in Taiwan and possibly some of the Southeast Asian countries. Although these residues are important biological evidences relating to the suspects, the forensic analysis of BQ evidence has been hindered by failures in extraction of human DNA for PCR analysis. Therefore, it is a prerequisite for relevant forensic casework to establish a reliable method for extracting DNA from chewed BQ residues. Three conventional methods (salt/chloroform, 5% Chelex-100 resin, and QIAamp) were first tested for extraction of human DNA from 33 mock BQ samples, which had been stored for less than two months, and 50 four-year-old forensic BQ samples. PCR amplifications from the HLA-DQA1&PM and the STR loci were then used to test the quality of the extracted DNA. For the mock samples, three observations were made. First, PCR amplification of DNA extracted by using these conventional methods had low success rate. Second, the addition of extra Taq DNA polymerase could compensate the lost enzyme activities due to putative inhibitors and, thus, increase the yield. Third, using the Centricon-100 column to remove putative inhibitors substantially improved the efficiency of PCR. However, for the four-year-old forensic BQ samples, none of the attempts for PCR were successful. In order to solve the problem in PCR analysis of DNA from old BQ samples, we developed a DNA extraction method based on the use of polyvinyl pyrrolidone (PVP) and cetyltrimethylammonium bromide (CTAB), which bind to two common classes of PCR inhibitors in plants, polyphenols, and polysaccharides, respectively. The result showed that this "PVP/CTAB" method is completely successful for the mock BQ samples, and 92% (46 out of 50) successful for the four-year-old forensic BQ samples. To our best knowledge, this is the first report of a reliable method for the extraction of human DNA for PCR from chewed BQ residues. This method should provide a useful means for

  15. Topological and functional relationship of subunits F1-gamma and F0I-PVP(b) in the mitochondrial H+-ATP synthase.

    PubMed

    Gaballo, A; Zanotti, F; Solimeo, A; Papa, S

    1998-12-15

    Diamide treatment of the F0F1-ATP synthase in "inside out" submitochondrial particles (ESMP) in the absence of a respiratory Delta mu H+ as well as of isolated Fo reconstituted with F1 or F1-gamma subunit results in direct disulfide cross-linking between cysteine 197 in the carboxy-terminal region of the F0I-PVP(b) subunit and cysteine 91 at the carboxyl end of a small alpha-helix of subunit F1-gamma, both located in the stalk. The F0I-PVP(b) and F1-gamma cross-linking cause dramatic enhancement of oligomycin-sensitive decay of Delta mu H+. In ESMP and MgATP particles the cross-linking is accompanied by decoupling of respiratory ATP synthesis. These effects are consistent with the view that F0I-PVP(b) and F1-gamma are components of the stator and rotor of the proposed rotary motor, respectively. The fact that the carboxy-terminal region of F0I-PVP(b) and the short alpha-helix of F1-gamma can form a direct disulfide bridge shows that these two protein domains are, at least in the resting state of the enzyme, in direct contact. In isolated F0, diamide also induces cross-linking of OSCP with another subunit of F0, but this has no significant effect on proton conduction. When ESMP are treated with diamide in the presence of Delta mu H+ generated by respiration, neither cross-linking between F0I-PVP(b) and F1-gamma subunits nor the associated effects on proton conduction and ATP synthesis is observed. Cross-linking is restored in respiring ESMP by Delta mu H+ collapsing agents as well as by DCCD or oligomycin. These observations indicate that the torque generated by Delta mu H+ decay through Fo induces a relative motion and/or a separation of the F0I-PVP(b) subunit and F1-gamma which places the single cysteine residues, present in each of the two subunits, at a distance at which they cannot be engaged in disulfide bridging.

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

    SciTech Connect

    Darwish, Maher; Mohammadi, Ali; Assi, Navid

    2016-02-15

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

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

    PubMed

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

    2011-03-21

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

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

    NASA Astrophysics Data System (ADS)

    Poda, Aimee R.; Kennedy, Alan J.; Cuddy, Michael F.; Bednar, Anthony J.

    2013-05-01

    This study investigated the effect of UV irradiation on the characteristics and toxicity of 50 nm (nominal diameter) polyvinylpyrrolidone-capped silver nanoparticles (AgNPs) in the presence and absence of dissolved organic carbon (DOC). The photolysis resulted in a decrease in average particle size as measured by field flow fractionation interfaced with inductively coupled plasma mass spectrometry. The decrease in size was attributed to the photo-induced oxidation of the PVP and dissolution of metallic silver. Moreover, photolysis of the AgNPs in solutions containing DOC appeared to give rise to small nanoparticles ( 5 nm) formed via reduction of dissolved silver ions. These results were consistent with photolysis of AgNO3 solutions initially devoid of nanoparticles. Thus, the carbon-containing constituents of DOC serve as reducing agents for Ag+, primarily under conditions of UV irradiation. The standard zooplankton model, Daphnia magna, indicated that the toxicity of nanosilver was significantly reduced when the AgNPs have been exposed to UV light. Observed toxicity was further reduced when AgNPs in DOC-containing solutions were exposed to UV. These results suggest that environmentally relevant conditions such as DOC and UV light are important mitigating factors that mediate the aquatic toxicity of AgNPs.

  19. Laser Raman, XRD, DSC and Ac-Impedance Analysis of Polymer Blend Electrolyte Based on Eco-Friendly Pva-Pvp Blend with NH4NO3

    NASA Astrophysics Data System (ADS)

    Rajeswari, N.; Selvasekarapandian, S.; Prabaharan, S. R. S.; Kawamura, J.; Iwai, Y.; Karthikeyan, S.

    2013-07-01

    Proton conducting polymer blend electrolytes have attractive interest because of their advantages such as processability, flexibility, electrochemical stability, easy handling and their applications to a variety of electrochemical devices such as fuel cells, chemical sensor and electrochemical displays. In the present work, the films of 50PVA-50PVP blend with different MWt% concentrations of NH4NO3 have been prepared by solution casting techniques using distilled water as a solvent. The prepared films have been investigated by different techniques such as XRD, DSC, Laser Raman and AC Impedance spectroscopy. XRD studies reveal the amorphous nature of the polymer blend-salt complexes. The glass transition temperature has been calculated from the DSC analysis. From the AC Impedance spectroscopy, the high conductivity of the 30MWt% of NH4NO3 doped 50PVA-50PVP polymer complex has been found to be the order of 1.41 × 10-3S cm-1 at room temperature.

  20. Effect of Complexation of NaCl Salt with Polymer Blend (PEO/PVP) Electrolytes on Ionic Conductivity and Optical Energy Band Gaps

    NASA Astrophysics Data System (ADS)

    Kumar, K. Kiran; Pavani, Y.; Ravi, M.; Bhavani, S.; Sharma, A. K.; Rao, V. V. R. Narasimha

    2011-10-01

    Sodium ion conducting polymer blend electrolyte films, based on polyethylene oxide (PEO) and poly vinyl pyrrolidone (PVP) complexed with NaCl salt, were prepared using solution casting technique. The complexation of the salt with the polymer blend was confirmed by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR) and UV-vis spectroscopy. Frequency and temperature dependence of electrical conductivity of the films was studied with impedance analyzer in the frequency range of 1 Hz to 1 MHz and in the temperature range of 303-348 K. UV-vis absorption spectra in wavelength region 200-800 nm, were used to evaluate the optical properties like direct and indirect optical energy band gaps, optical absorption edge. The optical band gaps decreased with the increase of Na+ ion concentration. This suggests that NaCl, as dopant, is a good choice to improve the electrical and optical properties of PEO/PVP polymer blend electrolytes.

  1. A theoretical study of red-shifting and blue-shifting hydrogen bonds occurring between imidazolidine derivatives and PEG/PVP polymers.

    PubMed

    Oliveira, Boaz G; Lima, Maria C A; Pitta, Ivan R; Galdino, Suely L; Hernandes, Marcelo Z

    2010-01-01

    A theoretical study is presented with the aim to investigate the molecular properties of intermolecular complexes formed by the monomeric units of polyvinylpyrrolidone (PVP) or polyethyleneglycol (PEG) polymers and a set of four imidazolidine (hydantoine) derivatives. The substitution of the carbonyl groups for thiocarbonyl in the hydantoin scaffold was taken into account when analyzing the effect of the hydrogen bonds on imidazolidine derivatives. B3LYP/6-31G(d,p) calculations and topological integrations derived from the quantum theory of atoms in molecules (QTAIM) were applied with the purpose of examining the N-H···O hydrogen bond strengths formed between the amide group of the hydantoine ring and the oxygen atoms of PVP and PEG polymers. The effects caused by the N-H···O interaction fit the typical evidence for hydrogen bonds, which includes a variation in the stretch frequencies of the N-H bonds. These frequencies were identified as being vibrational red-shifts because their values decreased. Although the values of such calculated interaction energies are between 12 and 33 kJ mol(-1), secondary intermolecular interactions were also identified. One of these secondary interactions is formed through the interaction of the benzyl hydrogen atoms with the oxygen atoms of the PVP and PEG structures. As such, we have analyzed the stretch frequencies on the C-H bonds of the benzyl groups, and blue-shifts were identified on these bonds. In this sense, the intermolecular systems formed by hydantoine derivatives and PVP/PEG monomers were characterized as a mix of red-shifting and blue-shifting hydrogen-bonded complexes.

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

    PubMed

    Albino, Giuseppe; Marucco, Ettore Cirillo

    2012-12-01

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

  3. Phase constituents and magnetic properties of the CoFe2O4 nanoparticles prepared by polyvinylpyrrolidone (PVP)-assisted hydrothermal route

    NASA Astrophysics Data System (ADS)

    Jalalian, M.; Mirkazemi, S. M.; Alamolhoda, S.

    2016-09-01

    In this research, nanoparticles of cobalt ferrite were synthesized by a simple hydrothermal process at 190 °C using different treatment durations with the assistance of polyvinylpyrrolidone (PVP) surfactant. The synthesized powders were characterized using X-ray diffraction (XRD), Raman spectroscopy, field emission scanning electron microscope and vibration sample magnetometer techniques. The quantitative values of phase constituents and also inversion parameter of cobalt ferrite spinel structure were calculated by Rietveld method using XRD results. XRD results show formation of cobalt ferrite as the main phase in all samples and also the presence of small amounts of Co3O4 lateral phase in some cases. Raman spectroscopies also confirm the presence of this lateral phase. Microstructural studies represent formation of nanoparticles with a narrow particle size distribution. Magnetic measurements represent that maximum magnetization ( M max) values are in the range of 25-57 emu/g with changes in the hydrothermal treatment duration. Intrinsic coercivity force values ( i H c ) change from 0 to 487 Oe in different samples. The highest M max value of 57 emu/g was obtained in the sample after 3 h of hydrothermal treatment with PVP addition. The i H c value of this sample was 35 Oe, while without PVP addition, the high M max value of 60 emu/g is observed in a sample that has i H c value equal to 320 Oe.

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

    PubMed

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

    2013-11-01

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

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

    NASA Astrophysics Data System (ADS)

    Karthikeyan, B.

    2017-02-01

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

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

    PubMed

    Karthikeyan, B

    2017-02-15

    In the present study, we report the preparation of NiO nanorods (NNR) and its Förster resonant energy transfer (FRET) behaviour with rhodamine 6G (R6G) in a Polyvinyl pyrrolidone (PVP) polymer matrix. The prepared nanocomposite polymer (NCP) films contain PVP and R6G whose concentrations are kept constant and different concentrations of NNR. Spectral overlap between the absorption and fluorescence spectrum of R6G and NNR shows the possibility of FRET phenomena to be occurring in the prepared NCP films. Steady state and time resolved fluorescence measurements are carried out at two excitation wavelengths (330 and 510nm) to study the energy transfer process between R6G and NNR in the PVP host. The obtained results show that the energy transfer is from R6G (serves as a donor) to NNR (functions as an acceptor). Calculated radiative efficiencies, donor-acceptor distances and average lifetime also confirm the energy transfer from R6G to NNR. Copyright © 2016 Elsevier B.V. All rights reserved.

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

    NASA Astrophysics Data System (ADS)

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

    2017-07-01

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

  8. 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%.

  9. Relating hydrogen-bonding interactions with the phase behavior of naproxen/PVP K 25 solid dispersions: evaluation of solution-cast and quench-cooled films.

    PubMed

    Paudel, Amrit; Nies, Erik; Van den Mooter, Guy

    2012-11-05

    In this work, we investigated the relationship between various intermolecular hydrogen-bonding (H-bonding) interactions and the miscibility of the model hydrophobic drug naproxen with the hydrophilic polymer polyvinylpyrrolidone (PVP) across an entire composition range of solid dispersions prepared by quasi-equilibrium film casting and nonequilibrium melt quench cooling. The binary phase behavior in solid dispersions exhibited substantial processing method dependence. The solid state solubility of crystalline naproxen in PVP to form amorphous solid dispersions was 35% and 70% w/w naproxen in solution-cast films and quench-cooled films, respectively. However, the presence of a single mixed phase glass transition indicated the amorphous miscibility to be 20% w/w naproxen for the films, beyond which amorphous-amorphous and/or crystalline phase separations were apparent. This was further supported by the solution state interactions data such as PVP globular size distribution and solution infrared spectral profiles. The borderline melt composition showed cooling rate dependence of amorphization. The glass transition and melting point depression profiles of the system were treated with the analytical expressions based on Flory-Huggins mixing theory to interpolate the equilibrium solid solubility. FTIR analysis and subsequent spectral deconvolution revealed composition and miscibility dependent variations in the strength of drug-polymer intermolecular H-bonding. Two types of H-bonded populations were evidenced from 25% w/w and 35% w/w naproxen in solution-cast films and quench-cooled films, respectively, with the higher fraction of strongly H-bonded population in the drug rich domains of phase separated amorphous film compositions and highly drug loaded amorphous quench-cooled dispersions.

  10. 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.

  11. Rapid transformation from spherical nanoparticles, nanorods, cubes, or bipyramids to triangular prisms of silver with PVP, citrate, and H2O2.

    PubMed

    Tsuji, Masaharu; Gomi, Satoshi; Maeda, Yoshinori; Matsunaga, Mika; Hikino, Sachie; Uto, Keiko; Tsuji, Takeshi; Kawazumi, Hirofumi

    2012-06-19

    Rapid sphere-to-prism (STP) transformation of silver was studied in aqueous AgNO(3)/NaBH(4)/polyvinylpyrrolidone (PVP)/trisodium citrate (Na(3)CA)/H(2)O(2) solutions by monitoring time-dependent surface plasmon resonance (SPR) bands in the UV-vis region, by examining transmission electron microscopic (TEM) images, and by analyzing emitted gases during fast reaction. Roles of PVP, Na(3)CA, and H(2)O(2) were studied without addition of a reagent, with different timing of each reagent's addition, and with addition of H(2)O(2) to mixtures of spheres and prisms. Results show that prisms can be prepared without addition of PVP, although it is useful to synthesize smaller monodispersed prisms. A new important role of citrate found in this study, besides a known role as a protecting agent of {111} facets of plates, is an assistive agent for shape-selective oxidative etching of Ag nanoparticles by H(2)O(2). The covering of Ag nanoparticles with carboxylate groups is necessary to initiate rapid STP transformation by premixing citrate before H(2)O(2) addition. Based on our data, rapid prism formation starts from the consumption of spherical Ag particles because of shape-selective oxidative etching by H(2)O(2). Oxidative etching of spherical particles by H(2)O(2) is faster than that of prisms. Therefore, spherical particles are selectively etched and dissolved, leaving only seeds of prisms to grow into triangular prisms. When pentagonal Ag nanorods and a mixture of cubes and bipyramids were used as sources of prisms, rod-to-prism (RTP), cube-to-prism (CTP), and bipyramid-to-prism (BTP) transformations were observed in Ag nanocrystals/NaBH(4)/PVP/Na(3)CA/H(2)O(2) solutions. Shape-selective oxidative etching of rods was confirmed using flag-type Ag nanostructures consisting of a triangular plate and a side rod. These data provide useful information for the size-controlled synthesis of triangular Ag prisms, from various Ag nanostructures and using a chemical reduction method

  12. Optimizing the ability of PVP/PEG mixtures to be used as appropriate carriers for the preparation of drug solid dispersions by melt mixing technique using artificial neural networks: I.

    PubMed

    Papadimitriou, Sofia A; Barmpalexis, Panagiotis; Karavas, Evangelos; Bikiaris, Dimitrios N

    2012-09-01

    In the present study, the efficiency of PVP/PEG200 mixtures as appropriate carries for the preparation of solid dispersions by melt mixing was evaluated. Felodipine (FELO) was used as a poorly water soluble model drug. The effect of several melt mixing parameters, (PVP/PEG ratio, time and temperature of melt mixing, and drug content), on the physical state of FELO and the dissolution characteristics of the dispersions were investigated. DSC, XRD, and SEM analysis revealed that in all cases, amorphous drug nanodispersions were prepared. This was attributed to the increased miscibility of the PVP-FELO system, induced by the presence of PEG200, which acted as plasticizer. FT-IR analysis showed hydrogen bonding between FELO (NH) and the PVP carrier (CO). The release rate of the drug depends mainly on the drug content and is higher in solid dispersions with low drug content and ratio of carrier to plasticizer (PVP/PEG200). The melt mixing variations (time and temperature of mixing) had lower impact on FELO release rate. Finally, artificial neural networks, used to correlate the examined formulation and process variables of hot melt mixing with dissolution parameters, showed good prediction ability.

  13. 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.

  14. Characterisation of the Poly-(Vinylpyrrolidone)-Poly-(Vinylacetate-Co-Crotonic Acid) (PVP:PVAc-CA) Interpolymer Complex Matrix Microparticles Encapsulating a Bifidobacterium lactis Bb12 Probiotic Strain.

    PubMed

    Mamvura, C I; Moolman, F S; Kalombo, L; Hall, A N; Thantsha, M S

    2011-06-01

    The method of producing poly-(vinylpyrrolidone)-poly-(vinylacetate-co-crotonic acid) (PVP:PVAc-CA) interpolymer complex matrix microparticles in supercritical carbon dioxide (scCO2), encapsulating bacteria, has recently been developed. This study was aimed at probing the external and internal structure of these microparticles, which can be used in food. The encapsulation efficiency and distribution of encapsulated Bifidobacterium lactis Bb12 within these microparticles were also investigated. Scanning electron microscopy (SEM) revealed irregular, mostly small, smooth microparticles with no visible bacterial cells on the surface. However, some of the microparticles appeared to have porous surfaces. The results of a Microtrac S3500 particle size analyzer showed that the PVP:PVAc-CA interpolymer complex matrix microparticles encapsulating B. lactis Bb12 had an average particle size of 166.1 μm (<350 μm designated standard size for microparticles). The D 10, D 50 and D 90 values for these microparticles were 48.16, 166.06 and 382.55 μm, respectively. Both SEM and confocal laser scanning microscopy showed a high density of bacterial cells within the microparticles. An average encapsulation efficiency of 96% was achieved. Consequently, the microparticles have the potential to be evenly distributed in foods, deliver adequate amounts of probiotics and produce minimal adverse effects on the texture and mouth feel of the foods into which they are incorporated.

  15. 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.

  16. Microwave irradiation induced modifications on the interfaces in SAN/EVA/PVC and PVAc/BPA/PVP ternary polymer blends: Positron lifetime study

    NASA Astrophysics Data System (ADS)

    Dinesh, Meghala; Chikkakuntappa, Ranganathaiah

    2013-09-01

    Ternary polymer blends of poly(styrene-co-acrylonitrile)/poly(ethylene-co-vinylacetate)/poly(vinyl chloride) (SAN/EVA/PVC) and poly(vinyl acetate)/bisphenol A/polyvinylpyrrolidone (PVAc/BPA/PVP) with different compositions have been prepared by solvent casting method and characterized by positron lifetime spectroscopy and differential scanning calorimetry DSC. Phase modifications have been induced by irradiating the blends with microwave radiation. These changes have been monitored by measuring the free-volume content in the blends. The results clearly show improved interactions between the constituent polymers of the blends upon microwave irradiation. However, the free-volume data and DSC measurements are found to be inadequate to reveal the changes at the interfaces and the interfaces determine the final properties of the blend. For this we have used hydrodynamic interaction (αij) approach developed by us to measure strength of hydrodynamic interaction at the interfaces. These results show that microwave irradiation stabilizes the interfaces if the blend contains strong polar groups. SAN/EVA/PVC blend shows an increased effective hydrodynamic interaction from -3.18 to -4.85 at composition 50/35/15 upon microwave irradiation and PVAc/BPA/PVP blend shows an increased effective hydrodynamic interaction from -3.81 to -7.57 at composition 20/50/30 after irradiation.

  17. Flexible resistive switching device based on poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS)/poly(4-vinylphenol) (PVP) composite and methyl red heterojunction

    NASA Astrophysics Data System (ADS)

    Hassan, Gul; Ali, Shawkat; Bae, Jinho; Lee, Chong Hyun

    2017-04-01

    To obtain a desired performance of non-volatile memory applications, heterojunction-based resistive switching devices have tremendous attractions. In this paper, we demonstrate resistive switching characteristics for heterojunction of poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS)/poly(4-vinylphenol) (PVP) composite and methyl red sandwiched in between bottom and top silver (Ag) electrodes. The proposed heterojunction layers are fabricated through spin coater at 3000 rpm for 60 s each, and the Ag electrodes are deposited through a commercialized inkjet printer DMP-3000 on polyethyleneterephthalate (PET) substrate. To verify the proposed device, the resistive switching on dual polarity voltage of ±10.2 V is measured over more than 500 endurance cycles. The paper also presents an R off/ R on ratio which can adjust through an active layer's area and a blending ratio of the PEDOT:PSS and PVP. By applying the area of 100 μm2 and the blending ratio of 3:1, we achieve the higher R off/ R on ratio of 121, and its high resistance state (HRS) and low resistance state (LRS) are observed as 3000 kΩ and 24.7 kΩ, respectively. To maintain a long retention time, the device is encapsulated with PDMS, which changes a little variations of 52 Ω for HRS 498 Ω for LRS over 60 days. For the flexible realization to be utilized in wearable applications, it can be easily applied on a plastic substrate using printed technologies.

  18. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2017-01-01

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

  20. Amorphous drug-PVP dispersions: application of theoretical, thermal and spectroscopic analytical techniques to the study of a molecule with intermolecular bonds in both the crystalline and pure amorphous state.

    PubMed

    Tobyn, Michael; Brown, Jonathan; Dennis, Andrew B; Fakes, Michael; Gao, Qi; Gamble, John; Khimyak, Yaroslav Z; McGeorge, Gary; Patel, Chhaya; Sinclair, Wayne; Timmins, Peter; Yin, Shawn

    2009-09-01

    We report the case of BMS-488043-PVP solid dispersions which when analysed using modulated DSC showed compliance with the Gordon-Taylor model, confirming ideal mixing behaviour of the two components. The nature or presence of stabilising interactions between drug and PVP could not be confirmed using this technique. Use of FT-IR, Raman and solid-state NMR spectroscopy confirmed the presence of stabilising hydrogen bond interactions between the drug and PVP. Similar interactions are present as intermolecular bonds in the crystalline and pure amorphous drug system. The Gordon-Taylor equation, as it is not predictive of the presence of intermolecular bonds such as hydrogen bonding in an amorphous dispersion, may underestimate the likely physical stability of solid dispersions which are produced and stabilised by these interactions.

  1. Effect of the polyvinylpyrrolidone concentration of cryoprotectant on mouse embryo development and production of pups: 7.5% of PVP is beneficial for in vitro and in vivo development of frozen-thawed mouse embryos.

    PubMed

    Kim, Chi-Gu; Yong, Hwanyul; Lee, Gene; Cho, Jaejin

    2008-08-01

    In this study, we investigated the effect of polyvinylpyrrolidone (PVP) concentration on in vitro and in vivo development of 2 cell stage, vitrified ICR mouse embryos using a cryoprotectant consisting of ethylene glycol (EG) and sucrose. M2 was selected as the basic medium for vitrification and thawing. After equilibration with 4% (v/v) EG at 37 C for 15 min, the embryos were vitrified with 35% EG, 5, 6 or 7.5% (w/v) PVP and 0.4 M sucrose at 37 C for 30 sec. One week later, the cryotubes of cryopreserved embryos in liquid nitrogen were directly immersed into a 37 C water bath for 1 min and transferred serially into 300 microl of 0.5 or 0.3 M sucrose at room temperature for 5 min and M2 medium at 37 C for 10 min. The surviving embryos were cultured in KSOM (potassium simplex optimized medium) for 96-120 h in an atmosphere of 5% CO(2) in humidified air. Survival was evaluated by morphological appearance, including membrane integrity and presence of apoptotic blastomeres after thawing. For in vivo evaluation, blastocysts were transferred to the uteri of pseudopregnant mice. The survival rates of the 5 and 7.5% PVP concentration groups showed a significantly higher difference compared with that of the 6% PVP group (85.5 and 86.5 vs. 71.2%), respectively. Each pup in the of 5 and 6% groups was cannibalized immediately after parturition. A litter of live pups was obtained from only the 7.5% PVP groups. Our study indicated that supplementation of EG and sucrose cryoprotectant solution with 7.5% PVP is optimal for successful vitrification of 2-cell stage ICR mouse embryos.

  2. Effect of Core-shell Ceria/Poly(Vinylpyrrolidone) (PVP) Nanoparticles Incorporated in Polymer Films and Their Optical Properties (2): Increasing the Refractive Index

    PubMed Central

    Itoh, Toshio; Uchida, Toshio; Izu, Noriya; Shin, Woosuck

    2017-01-01

    We investigated the preparation of well-dispersed core-shell ceria-poly(vinylpyrrolidone) (PVP) nanoparticles with an average particle size of around 20 nm which were used to produce a hybrid film with a polymer coating of dipentaerythritol hexaacrylate (DPHA). We obtained good dispersion of the nanoparticles in a mixed solvent of 48% 1-methoxy-2-propanol (MP), 32% 3-methoxy-3-methyl-1-butanol (MMB), and 20% methyl i-butyl ketone (MIBK). An ink of the polymer coating consisting of 68.7 wt% nanoparticles and 31.3 wt% DPHA with a polymerization initiator was prepared using this solvent mixture. The surface of the hybrid film showed low roughness and the nanoparticles formed a densely packed structure in the DPHA matrix. The resulting coating possessed excellent transparency and a high refractive index of 1.69. PMID:28773070

  3. 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

    2015-07-17

    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.

  4. NMR spectroscopy and MALDI-TOF MS characterisation of end-functionalised PVP oligomers prepared with different esters as chain transfer agents.

    PubMed

    Ranucci, Elisabetta; Ferruti, Paolo; Annunziata, Rita; Gerges, Irini; Spinelli, Giuseppe

    2006-03-14

    Ester-functionalised poly(1-vinylpyrrolidin-2-one) (PVP) oligomers obtained by radical polymerisation in methyl propionate, diethyl malonate and diethyl 2-methylmalonate were characterised by NMR spectroscopy, and MALDI-TOF mass spectrometry. The chain-transfer constants were determined as 5.54 x 10(-4), 1.22 x 10(-3) and 1.70 x 10(-2), respectively, by measuring the variation of the number-average molecular weight on conversion. These values were compared with those of methyl isobutyrate (1.65 x 10(-3)) and ethyl lactate (1.03 x 10(-2)), which had been previously determined. A clear dependence was found on the reactivity of the mobile hydrogen atoms alpha with the ester group. All of the macromolecules carried a single ester function. Therefore, the re-initiation step by the CTA-derived radicals overwhelmingly prevailed over initiation by the primary radicals.

  5. The dangerous new synthetic drug α-PVP as the hydrated chloride salt α-pyrrolidinopentiophenone hydrochloride 0.786-hydrate.

    PubMed

    Wood, Matthew R; Bernal, Ivan; Lalancette, Roger A

    2016-01-01

    α-Pyrrolidinovalerophenone (α-PVP), a dangerous designer drug, is now being marketed around the world as a harmless `bath salt', when in reality it is a powerful β-ketone phenethylamine stimulant. A sample of the free base from a recent law-enforcement seizure was crystallized as the HCl salt [systematic name: 1-(1-oxo-1-phenylpentan-2-yl)pyrrolidin-1-ium chloride 0.786-hydrate], C15H22NO(+)·Cl(-)·0.786H2O. In the crystal structure, the propyl chain is nearly perpendicular to both the phenyl ring and the carbonyl group. The hydrogen-bonding scheme involves the quaternary N atom, the Cl(-) anion and the partially occupied (0.786) water molecule, forming centrosymmetric dimers.

  6. [The detection and identification of alpha-pyrrolidino-valerophenone (α-PVP) and its metabolites in the objects of the forensic chemical examination].

    PubMed

    Moskaleva, E V; Eroshchenko, N N; Kiryushin, A N; Kardonsky, D A; Eganov, A A

    2017-01-01

    The combined application of the IK 200609 chemical toxicological analyzer and the diagnostic biosensor (reagent) for the determination of synthetic cations (with due regard for compliance with the instruction for analysis) made it possible to detect during 15 minutes the presence of cations in the urine samples at the concentration of 376.64 ng/ml. This result was further confirmed by HPLC-Ms/MS and GH-MS. The use of the analyzer allowed the screening of the urine samples to be performed within several minutes at the preliminary stage of the study. A simplified method of tissue sample preparation with the use of the kits for extraction and solid-phase purification is proposed together with a variant of blood sample preparation with the use of filtration. The proposed approach can be employed for the rapid detection and identification of alpha-pyrrolidino-valerophenone (α-PVP) and its metabolites in urine, blood and tissues of various organs for the purpose of practical toxicological investigations in the framework of forensic chemical expertise.

  7. Bioevaluation of novel anti-biofilm coatings based on PVP/Fe3O4 nanostructures and 2-((4-ethylphenoxy)methyl)-N- (arylcarbamothioyl)benzamides.

    PubMed

    Limban, Carmen; Missir, Alexandru Vasile; Grumezescu, Alexandru Mihai; Oprea, Alexandra Elena; Grumezescu, Valentina; Vasile, Bogdan Stefan; Socol, Gabriel; Trușcă, Roxana; Caproiu, Miron Teodor; Chifiriuc, Mariana Carmen; Gălățeanu, Bianca; Costache, Marieta; Morușciag, Laurențiu; Pîrcălăbioru, Grațiela; Nuță, Diana Camelia

    2014-08-12

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

  8. 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.

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

    PubMed

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

    2017-09-01

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

  10. 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

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

    PubMed

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

    2017-07-01

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

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

    PubMed

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

    2017-02-13

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

  13. The effect of pressurized carbon dioxide as a temporary plasticizer and foaming agent on the hot stage extrusion process and extrudate properties of solid dispersions of itraconazole with PVP-VA 64.

    PubMed

    Verreck, Geert; Decorte, Annelies; Heymans, Koen; Adriaensen, Jef; Cleeren, Dirk; Jacobs, Adri; Liu, Dehua; Tomasko, David; Arien, Albertina; Peeters, Jef; Rombaut, Patrick; Van den Mooter, Guy; Brewster, Marcus E

    2005-11-01

    The aim of the current research project was to explore the possibilities of combining pressurized carbon dioxide with hot stage extrusion during manufacturing of solid dispersions of itraconazole and polyvinylpyrrolidone-co-vinyl acetate 64 (PVP-VA 64) and to evaluate the ability of the pressurized gas to act as a temporary plasticizer as well as to produce a foamed extrudate. Pressurized carbon dioxide was injected into a Leistritz Micro 18 intermeshing co-rotating twin-screw melt extruder using an ISCO 260D syringe pump. The physicochemical characteristics of the extrudates with and without injection of carbon dioxide were evaluated with reference to the morphology of the solid dispersion and dissolution behaviour and particle properties. Carbon dioxide acted as plasticizer for itraconazole/PVP-VA 64, reducing the processing temperature during the hot stage extrusion process. Amorphous dispersions were obtained and the solid dispersion was not influenced by the carbon dioxide. Release of itraconazole from the solid dispersion could be controlled as a function of processing temperature and pressure. The macroscopic morphology changed to a foam-like structure due to expansion of the carbon dioxide at the extrusion die. This resulted in increased specific surface area, porosity, hygroscopicity and improved milling efficiency.

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

    PubMed

    Asadpour-Zeynali, Karim; Mollarasouli, Fariba

    2017-06-15

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

  15. 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.

  16. [Photoselective vaporization of the prostate (PVP) using 80 watt high power potassium-titanyl-phosphate (KTP) laser for benign prostatic hyperplasia: the first fifty-seven patients in Japan].

    PubMed

    Kuromatsu, Isao; Imamura, Tetsuya; Sugimura, Yoshiki

    2006-11-01

    To assess the safety and efficacy of photoselective vaporization of the prostate (PVP) using 80 watt high power potassium-titanyl-phosphate (KTP) laser for benign prostatic hyperplasia (BPH). Fifty-seven patients with lower urinary tract symptoms secondary to benign prostatic hyperplasia underwent 80 W KTP laser vaporization of the prostate. According to their International Prostate Symptom Score Index (IPSS) and Quality of life (QOL) score as well as measurements of their peak flow rate and postvoiding residual urine volume (RUV), they fulfilled the diagnostic criteria of BPH. Vaporization was performed with the GreenLight PV ADDStat fiber, which was inserted through a 22.5Fr. continuous flow laser cystoscope, and a saline solution was used for irrigation. KTP laser energy was generated by a GreenLight PV (Minnetonka, Minnesota) generator. The end point of the procedure was to create a cavity like in TURP. Once vaporization was completed, an18Fr Foley catheter was inserted and was removed the next morning, as a rule. Patients were evaluated preoperatively, and at 2 weeks and 1, 3 and 6 months postoperatively. The procedure could be performed without any intraoperative complication. None of the patients required continuous bladder irrigation or blood transfusion postoperatively. The mean age was 71.0 +/- 8.3 years (range 52 to 86). The preoperative prostate volume was 41.0 +/- 24.9 (mean +/- SD, range 6.7 to 107.2) and the preoperative serum PSA was 4.5 +/- 4.1 ng/ml. Preoperative and immediate postoperative serum sodium concentration was 141.9 +/- 1.8 mEq/L and 142.2 +/- 1.8 mEq/L, respectively (p = 0.23). The hemoglobin value changed from 14.0 +/- 1.4 mg/dl preoperatively to 13.4 +/- 1.4 mg/dl postoperatively. The operating time was 68.3 +/- 35.0 minutes (range 21 to 170) and total laser energy was 171.1 +/- 80.3 kJ (range 18.1 to 484.8). The catheter indwelling time was 18.6 +/- 3.3 hrs (range 15 to 48). At 2 weeks and 1, 3 and 6 months the International

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

    NASA Astrophysics Data System (ADS)

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

    2017-10-01

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

  18. Flow-induced vibration -- 1996. PVP-Volume 328

    SciTech Connect

    Pettigrew, M.J.; Paidoussis, M.P.; Weaver, D.S.; Au-Yang, M.K.

    1996-12-01

    Although much progress has been made in the last three decades, flow-induced vibration is still the cause of many costly failures in nuclear power plants and process industries. Reasonable design guidelines have been developed to avoid flow-induced problems at the design stage of some areas. However, much work remains to be done in other areas such as two-phase flow-induced vibration, fretting-wear damage prediction, and acoustically induced piping vibration. Hopefully, this Symposium is a significant contribution to understanding vibration excitation mechanisms and to avoiding flow-induced vibration problems. Separate abstracts were prepared for all 45 papers in this volume.

  19. Flow-setup for in situ XAFS measurement to probe growth of PVP stabilized Cu nanoparticles

    NASA Astrophysics Data System (ADS)

    Nayak, C.; Bhattacharyya, D.; Jha, S. N.; Sahoo, N. K.

    2017-05-01

    A computer-controlled flow setup has been designed and implemented at the Energy Dispersive EXAFS beamline (BL-08) at INDUS-2 SRS which facilitates in situ time-resolved X-ray Absorption Spectroscopy (XAS) measurements on reactions carried out under specialized experimental conditions. The set-up has been tested by in-situ time resolved X-ray near edge structure (XANES) measurement on the evolution of the reduction process during synthesis of Cu nanoparticles under N2 ambient by reducing Cu(II) Acetate precursor with NaBH4.

  20. 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.

  1. 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.

  2. Electromechanical resonator based on electrostatically actuated graphene-doped PVP nanofibers.

    PubMed

    Fardindoost, S; Mohammadi, S; Iraji zad, A; Sarvari, R; Shariat Panahi, S P; Jokar, E

    2013-04-05

    In this paper we present experimental results describing electrical readout of the mechanical vibratory response of graphene-doped fibers by employing electrical actuation. For a fiber resonator with an approximate radius of 850 nm and length of 100 μm, we observed a resonance frequency around 580 kHz with a quality factor (Q) of about 2511 in air at ambient conditions. Through the use of finite element simulations, we show that the reported frequency of resonance is relevant. We also show that the resonance frequency of the fiber resonators decreases as the bias potential is increased due to the electrostatic spring-softening effect.

  3. Combined chlorhexidine and PVP-I decontamination of human donor eyes prior to corneal preservation.

    PubMed

    van Luijk, Chantal M; Bruinsma, Marieke; van der Wees, Jacqueline; Lie, Jessica T; Ham, Lisanne; Melles, Gerrit R J

    2012-06-01

    The aim of this study was to report the efficacy of adding chlorhexidine to the protocol for decontamination of human donor globes prior to excision of corneo-scleral rims for future keratoplasty procedures. In 2005, chlorhexidine was introduced by our eye bank as an additional step in the protocol for decontaminating human donor globes. After 5 years, we prospectively evaluated the number of contaminations. Out of 2,891 globes included in our study, 2,663 globes were processed, of which 36 (1.4%) were considered contaminated. Seventeen contaminations (0.6%) were detected by culturing limbal swabs, directly after decontamination, eight (0.3%) by visible discoloration of the culture medium carrying a corneo-scleral rim, and eleven (0.4%) after inoculation of the culture medium on blood agar plates. Importantly, after 4 weeks of incubation, none of the aerobic and anaerobic cultures taken from the secondary 'transport medium' (dextran containing medium used to transport corneal tissue to the transplantation centre) showed microbiological growth. In conclusion, the combined use of 0.02% chlorhexidine and 0.5% povidone-iodine may allow decontamination of donor globes to a level at which the risk of tissue contamination at the time of transplantation is minimized, while corneal viability is preserved.

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

    NASA Astrophysics Data System (ADS)

    Divyasree, M. C.; Chandrasekharan, K.

    2017-05-01

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

  5. A simple and rapid method for isolation of high quality genomic DNA from fruit trees and conifers using PVP.

    PubMed Central

    Kim, C S; Lee, C H; Shin, J S; Chung, Y S; Hyung, N I

    1997-01-01

    Because DNA degradation is mediated by secondary plant products such as phenolic terpenoids, the isolation of high quality DNA from plants containing a high content of polyphenolics has been a difficult problem. We demonstrate an easy extraction process by modifying several existing ones. Using this process we have found it possible to isolate DNAs from four fruit trees, grape (Vitis spp.), apple (Malus spp.), pear (Pyrus spp.) and persimmon (Diospyros spp.) and four species of conifer, Pinus densiflora, Pinus koraiensis,Taxus cuspidata and Juniperus chinensis within a few hours. Compared with the existing method, we have isolated high quality intact DNAs (260/280 = 1.8-2.0) routinely yielding 250-500 ng/microl (total 7.5-15 microg DNA from four to five tissue discs). PMID:9023124

  6. Proceedings of the 1985 pressure vessels and piping conference. Volume PVP-98-2. Pressure vessel components design and analysis

    SciTech Connect

    Gawaltney, R.C.

    1985-01-01

    There are seven sessions covered in this book on Pressure Vessel Components Design and Analysis. The papers are divided into the following six subject areas: composites, valves, tubesheets, pressure vessels and piping, bolted flanges, and nonlinear computational methods. The design procedures and analysis methods described in this book are not discussed previously. The engineers working in the field of pressure vessel design can only keep up with current developments in these areas by reviewing a substantial amount of technical literature. A goal of this book is to help in this endeavor by offering selected papers in the area by authors who are experienced and distinguished workers in their fields.

  7. 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

  8. 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.

  9. 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

  10. Li + ion diffusion in Li 4Ti 5O 12 thin film electrode prepared by PVP sol-gel method

    NASA Astrophysics Data System (ADS)

    Rho, Young Ho; Kanamura, Kiyoshi

    2004-06-01

    Li 4Ti 5O 12 thin films for rechargeable lithium batteries were prepared by a sol-gel method with poly(vinylpyrrolidone). Interfacial properties of lithium insertion into Li 4Ti 5O 12 thin film were examined by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and potentiostatic intermittent titration technique (PITT). Redox peaks in CV were very sharp even at a fast scan rate of 50 mV s -1, indicating that Li 4Ti 5O 12 thin film had a fast electrochemical response, and that an apparent chemical diffusion coefficient of Li + ion was estimated to be 6.8×10 -11 cm 2 s -1 from a dependence of peak current on sweep rates. From EIS, it can be seen that Li + ions become more mobile at 1.55 V vs. Li/Li +, corresponding to a two-phase region, and the chemical diffusion coefficients of Li + ion ranged from 10 -10 to 10 -12 cm 2 s -1 at various potentials. The chemical diffusion coefficients of Li + ion in Li 4Ti 5O 12 were also estimated from PITT. They were in a range of 10 -11-10 -12 cm 2 s -1.

  11. 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.

  12. 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

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

    PubMed

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

    2013-02-26

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

  14. 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.

  15. 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. Copyright © 2013 Elsevier GmbH. All rights reserved.

  16. [Testing of mucosa disinfection methods in the mouth and throat. 1. Effect of chlorhexidine gluconate and PVP-iodine on alpha-hemolytic streptococci].

    PubMed

    Exner, M; Gregori, G

    1984-12-01

    A method for testing a throat antiseptic procedure is described. As indicator bacteria alpha-hemolytic streptococci were chosen. Povidone-Iodine and Chlorhexidindigluconate (0.5% and 0.1%) and aqua dest. as control substance were tested by a mouthwash technique. The best reduction of alpha-hemolytic streptococci could be detected after mouthwashing by 0.5% Chlorhexidindigluconate (1.4 log reduction), whereas by Povidone-Iodine a reduction of 0.85 log steps was achieved.

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

    PubMed

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

    2015-01-01

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

  18. 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.

  19. Highly dynamic PVP-coated silver nanoparticles in aquatic environments: chemical and morphology change induced by oxidation of Ag(0) and reduction of Ag(+).

    PubMed

    Yu, Su-Juan; Yin, Yong-Guang; Chao, Jing-Bo; Shen, Mo-Hai; Liu, Jing-Fu

    2014-01-01

    The fast growing and abundant use of silver nanoparticles (AgNPs) in commercial products alerts us to be cautious of their unknown health and environmental risks. Because of the inherent redox instability of silver, AgNPs are highly dynamic in the aquatic system, and the cycle of chemical oxidation of AgNPs to release Ag(+) and reconstitution to form AgNPs is expected to occur in aquatic environments. This study investigated how inevitable environmentally relevant factors like sunlight, dissolved organic matter (DOM), pH, Ca(2+)/Mg(2+), Cl(-), and S(2-) individually or in combination affect the chemical transformation of AgNPs. It was demonstrated that simulated sunlight induced the aggregation of AgNPs, causing particle fusion or self-assembly to form larger structures and aggregates. Meanwhile, AgNPs were significantly stabilized by DOM, indicating that AgNPs may exist as single particles and be suspended in natural water for a long time or delivered far distances. Dissolution (ion release) kinetics of AgNPs in sunlit DOM-rich water showed that dissolved Ag concentration increased gradually first and then suddenly decreased with external light irradiation, along with the regeneration of new tiny AgNPs. pH variation and addition of Ca(2+) and Mg(2+) within environmental levels did not affect the tendency, showing that this phenomenon was general in real aquatic systems. Given that a great number of studies have proven the toxicity of dissolved Ag (commonly regarded as the source of AgNP toxicity) to many aquatic organisms, our finding that the effect of DOM and sunlight on AgNP dissolution can regulate AgNP toxicity under these conditions is important. The fact that the release of Ag(+) and regeneration of AgNPs could both happen in sunlit DOM-rich water implies that previous results of toxicity studies gained by focusing on the original nature of AgNPs should be reconsidered and highlights the necessity to monitor the fate and toxicity of AgNPs under more environmentally relevant conditions.

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

    PubMed

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

    2013-07-01

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

  1. Effect of polyvinylpyrrolidone on the structure and laser damage resistance of sol gel silica anti-reflective films

    NASA Astrophysics Data System (ADS)

    Zhang, Lei; Xu, Yao; Wu, Dong; Sun, Yuhan; Jiang, Xiaodong; Wei, Xiaofeng

    2008-03-01

    The effect of polyvinylpyrrolidone (PVP) on the structure and laser-induced damage threshold (LIDT) of sol-gel silica anti-reflective films is investigated. The results of dynamic light scattering, transmission electron microscopy, and small angle X-ray scattering, show that the PVP molecules surrounded the silica sol particles through the strong hydrogen bonds between Si-OH groups and the PVP. As a result, the growth of silica particles was restricted and thus the interface layer between the silica particles and the solvent become thickened with PVP content. Furthermore, the PVP reduced the porosity of the film, so the anti-reflection properties of the film were weakened. A multi-fractal analysis showed that the appropriate addition of PVP, 1 weight percent (wt%), could improve the surface fractal structure of the film, but that higher PVP content resulted in reduced surface uniformity. The addition of PVP lead to improved LIDT.

  2. Identifying Drugs

    MedlinePlus

    ... Fentanyl Flakka (alpha-PVP) GHB - Gamma-Hydroxybutyric Acid Heroin Hydromorphone Inhalants Ketamine Khat Kratom LSD Marijuana Methadone ... Fentanyl Flakka (alpha-PVP) GHB - Gamma-Hydroxybutyric Acid Heroin Hydromorphone Inhalants Ketamine Khat Kratom LSD Marijuana Methadone ...

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

    NASA Astrophysics Data System (ADS)

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

    2016-10-01

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

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

    PubMed

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

    2012-01-01

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

  5. Polyvinylpyrrolidone induced artefactual prolongation of activated partial thromboplastin times in intravenous drug users with renal failure.

    PubMed

    Kristoffersen, A H; Bjånes, T K; Jordal, S; Leh, S; Leh, F; Svarstad, E

    2016-05-01

    Essentials Prolonged activated partial thromboplastin times (APTT) were found in drug users with renal failure. An oral methadone solution containing polyvinylpyrrolidone (PVP) had been injected intravenously. Spiking normal plasma with increasing concentrations of PVP resulted in artifically prolonged APTT. APTT prolongation may indicate PVP deposits as underlying cause in patients with renal failure.

  6. Complications in Percutaneous Vertebroplasty Associated with Puncture or Cement Leakage

    SciTech Connect

    Baumann, Clemens Fuchs, Heiko; Kiwit, Juergen; Westphalen, Kerstin; Hierholzer, Johannes

    2007-04-15

    Due to the minimally invasive character and excellent clinical outcome of percutaneous vertebroplasty (PVP), the procedure is being performed in greatly increasing numbers. While PVP has a low complication rate in general, severe complications can occur. We focus on the imaging appearance of complications of PVP associated with puncture or cement leakage-from harmless to life-threatening.

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

    PubMed

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

    2013-01-01

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

  8. Preparation of corneal donor eyes comparing 1% versus 5% povidone-iodine.

    PubMed

    Lindquist, Thomas D; Maxwell, Andrew J; Miller, Thomas D; Win'E, Troy L; Novicki, Thomas; Fritsche, Thomas R; Iliakis, Bernardino; Montoya, Monty

    2011-03-01

    To compare the effect of 1% versus 5% polyvinylpyrrolidone-iodine (PVP-I) chemical preparation (prep) of the eye on the recovery of organisms from donor globes before in situ recovery of donor corneal tissue. One hundred consecutive pairs of donor corneas (200 eyes) were randomized to receive either 1% or 5% PVP-I drops applied to the conjunctival cul-de-sac, which was left in place for 2 minutes. Limbal cultures were obtained before and after prepping of the eye. Twenty-five different species of organisms were recovered. Native flora of the eye included coagulase-negative staphylococci (62%), Corynebacterium species (27%), streptococcal species (9.5%), gram-negative bacilli (14.5%), Staphylococcus aureus (5%), anaerobes (10%), and yeast (2%). After PVP-I instillation of the donor eye, 74 isolates were recovered from the 1% P-I group and 76 isolates from the 5% PVP-I group. Cultures were sterile after PVP-I prep in 49 eyes and 47 eyes in the 1% PVP-I group and 5% PVP-I group, respectively. Microorganism colony forming units were similar among post-prep cultures from both PVP-I groups. The effect of the PVP-I prep on the number of negative cultures and on the reduction in the number of isolates was highly significant for both the 1% PVP-I group and the 5% PVP-I group when compared with the limbal cultures taken before PVP-I instillation. This study found that 1% and 5% PVP-I solutions are equally effective for chemical prep of the donor eye. Because PVP-I is known to be toxic to the corneal endothelium and corneal fibroblasts, this study suggests that 1% PVP-I should be the preferred disinfectant for the recovery of corneal donors.

  9. 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.

  10. 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.

  11. Biomimetic branched hollow fibers templated by self-assembled fibrous polyvinylpyrrolidone structures in aqueous solution.

    PubMed

    Qiu, Penghe; Mao, Chuanbin

    2010-03-23

    Branched hollow fibers are common in nature, but to form artificial fibers with a similar branched hollow structure is still a challenge. We discovered that polyvinylpyrrolidone (PVP) could self-assemble into branched hollow fibers in an aqueous solution after aging the PVP solution for about two weeks. On the basis of this finding, we demonstrated two approaches by which the self-assembly of PVP into branched hollow fibers could be exploited to template the formation of branched hollow inorganic fibers. First, inorganic material such as silica with high affinity against the PVP could be deposited on the surface of the branched hollow PVP fibers to form branched hollow silica fibers. To extend the application of PVP self-assembly in templating the formation of hollow branched fibers, we then adopted a second approach where the PVP molecules bound to inorganic nanoparticles (using gold nanoparticles as a model) co-self-assemble with the free PVP molecules in an aqueous solution, resulting in the formation of the branched hollow fibers with the nanoparticles embedded in the PVP matrix constituting the walls of the fibers. Heating the resultant fibers above the glass transition temperature of PVP led to the formation of branched hollow gold fibers. Our work suggests that the self-assembly of the PVP molecules in the solution can serve as a general method for directing the formation of branched hollow inorganic fibers. The branched hollow fibers may find potential applications in microfluidics, artificial blood vessel generation, and tissue engineering.

  12. Water vapor absorption into amorphous hydrophobic drug/poly(vinylpyrrolidone) dispersions.

    PubMed

    Crowley, Kieran J; Zografi, George

    2002-10-01

    Water vapor absorption isotherms were measured for three amorphous hydrophobic drug/poly(vinylpyrrolidone) (PVP) dispersions in the concentration range 10-90% w/w PVP. Experimental isotherms were compared to predicted isotherms calculated using each individual component isotherm multiplied by its weight fraction. Indomethacin (IMC)/PVP, ursodeoxycholic acid (UDCA)/PVP and indapamide (IDP)/PVP amorphous dispersions all exhibited experimental isotherms reduced relative to predicted isotherms indicating that dispersion formation altered the water vapor absorption properties of the individual components. For all three drug/PVP systems, deviation from predicted water uptake was greatest close to the 1:1 drug:PVP monomer composition, indicating that intermolecular interaction in amorphous dispersions affects the water uptake properties of the individual components. Using dry glass transition temperature (T(g)) data, the extent of drug/PVP interaction was shown to be greatest in the IDP/PVP system, which could explain why the largest reduction in water vapor absorption was found in this system. The plasticizing effect of absorbed water varied according to dry dispersion PVP content in all systems and the resulting nonideal changes in free volume, calculated using the Vrentas model, were greatest close to the 1:1 drug:PVP monomer composition. A three-component Flory-Huggins model successfully predicted isotherms for IMC/PVP compositions from 60 to 90% w/w PVP and identified an IMC-PVP interaction parameter chi in the range 1.27-1.49, values that suggest poor homogeneity of mixing in the dry system. These data indicate that amorphous dispersion formation causes both chemical and physical changes in the individual amorphous components that can have a significant effect on their water vapor absorption properties.

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

    PubMed

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

    2016-12-01

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

  14. Use of polyvinylpyrrolidone-iodine solution for sterilisation and preservation improves mechanical properties and osteogenesis of allografts

    PubMed Central

    Zhao, Yantao; Hu, Xiantong; Li, Zhonghai; Wang, Fuli; Xia, Yang; Hou, Shuxun; Zhong, Hongbin; Zhang, Feimin; Gu, Ning

    2016-01-01

    Allografts eliminate the disadvantages associated with autografts and synthetic scaffolds but are associated with a disease-transmission risk. Therefore, allograft sterilisation is crucial. We aimed to determine whether polyvinylpyrrolidone-iodine (PVP-I) can be used for sterilisation and as a new wet-preservation method. PVP-I–sterilised and preserved allografts demonstrated improved mechanical property, osteogenesis, and excellent microbial inhibition. A thigh muscle pouch model of nude mice showed that PVP-I–preserved allografts demonstrated better ectopic formation than Co60-sterilised allografts (control) in vivo (P < 0.05). Furthermore, the PVP-I–preserved group showed no difference between 24 h and 12 weeks of allograft preservation (P > 0.05). PVP-I–preserved allografts showed more hydrophilic surfaces and PVP-I–sterilised tendons showed higher mechanical strength than Co60-sterilised tendons (P < 0.05). The level of residual PVP-I was higher without washing and with prolonged preservation (P < 0.05). In vitro cellular tests showed that appropriate PVP-I concentration was nontoxic to preosteoblast cells, and cellular differentiation measured by alkaline phosphatase activity and osteogenic gene markers was enhanced (P < 0.05). Therefore, the improved biological performance of implanted allografts may be attributable to better surface properties and residual PVP-I, and PVP-I immersion can be a simple, easy method for allograft sterilisation and preservation. PMID:27934929

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

    PubMed

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

    2016-10-14

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

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

    NASA Astrophysics Data System (ADS)

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

    2017-02-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2016-10-01

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

  18. Surface-enhanced Raman scattering of 4-mercaptobenzoic acid and hemoglobin adsorbed on self-assembled Ag monolayer films with different shapes

    NASA Astrophysics Data System (ADS)

    Zhu, Shuangmei; Fan, Chunzhen; Wang, Junqiao; He, Jinna; Liang, Erjun

    2014-06-01

    Polyvinylpyrrolidone (PVP)-protected silver nanostructures of various shapes, including nanocubes, nanospheres, and hybrid shapes with nanospheres and nanorods, on the surface of glass or Si substrates (PVP-Ag films) are prepared by using electrostatic self-assembly. With 4-mercaptobenzoic acid (4-MBA) as a probe molecule, it is demonstrated that the PVP-protected silver nanocubes films (PVP-Ag NCs) have better surface-enhanced Raman scattering (SERS) activity with an order of magnitude larger enhancement factors (EF) than the PVP-protected silver nanospheres films and the PVP-protected silver hybrid shapes films, which is confirmed by our numerical simulations. The EF of 4-MBA on the PVP-Ag NCs film are up to ~5.38 × 106, and the detection limit is at least down to ~10-8 M. The uniformity and reproducibility of the SERS signals on PVP-Ag NCs film are tested by point-to-point and batch-to-batch measurements. Meanwhile, the PVP-Ag films are also shown to be an excellent SERS substrate with good biocompatibility for hemoglobin detection. It is shown that the PVP-Ag NCs films can be used as excellent SERS substrate with good activity, uniformity, reproducibility, and biocompatibility and are promising for a myriad of chemical and biochemical sensing applications.

  19. Improved chlorine tolerance of a polyvinyl pyrrolidone-polysulfone membrane enabled by carboxylated carbon nanotubes.

    PubMed

    Xie, Pengchao; de Lannoy, Charles-François; Ma, Jun; Wang, Zongping; Wang, Songlin; Li, Jingjing; Wiesner, Mark R

    2016-11-01

    Chemical cleaning of membranes may be limited by the tolerance of some polymeric membranes to chlorine. In this work we show that modification of a polyvinyl pyrrolidone-polysulfone (PVP-PSF) membrane with carboxylated carbon nanotubes (CNTs) leads to greater chlorine tolerance of the membrane along with smoothing the surface roughness and improving some membrane properties including permeability, hydrophilicity and antifouling ability. In comparison with PVP-PSF membrane, incorporating carboxylated CNTs reduced the release of organic matter from the membrane and caused less decrease in hydrophilicity, permeability and BSA rejection. After chlorine treatment of a conventional PVP-PSF membrane, an infrared absorbance peak around 1670 cm(-1), representing the vibration of the amide bond in the PVP, decreased significantly and two smaller peaks at around 1725 and 1775 cm(-1) were observed. The percentage of C-Cl (2p) in the PVP-PSF membrane was about 2.8 times greater than that of the carboxylated CNT-composite PVP-PSF (CNT-PVP-PSF) membrane after chlorine exposure, suggesting greater chlorine tolerance of CNT-PVP-PSF membrane. In comparison with PVP-PSF membrane, the formation of toxic chlorinated byproducts during chlorination of organic matter released from CNT-PVP-PSF membrane was much lower. The improvement of tolerance to chlorine is attributed to stabilization of the polymer through hydrogen bonding between polymer and carboxylated CNTs. Copyright © 2016 Elsevier Ltd. All rights reserved.

  20. Use of polyvinylpyrrolidone-iodine solution for sterilisation and preservation improves mechanical properties and osteogenesis of allografts

    NASA Astrophysics Data System (ADS)

    Zhao, Yantao; Hu, Xiantong; Li, Zhonghai; Wang, Fuli; Xia, Yang; Hou, Shuxun; Zhong, Hongbin; Zhang, Feimin; Gu, Ning

    2016-12-01

    Allografts eliminate the disadvantages associated with autografts and synthetic scaffolds but are associated with a disease-transmission risk. Therefore, allograft sterilisation is crucial. We aimed to determine whether polyvinylpyrrolidone-iodine (PVP-I) can be used for sterilisation and as a new wet-preservation method. PVP-I-sterilised and preserved allografts demonstrated improved mechanical property, osteogenesis, and excellent microbial inhibition. A thigh muscle pouch model of nude mice showed that PVP-I-preserved allografts demonstrated better ectopic formation than Co60-sterilised allografts (control) in vivo (P < 0.05). Furthermore, the PVP-I-preserved group showed no difference between 24 h and 12 weeks of allograft preservation (P > 0.05). PVP-I-preserved allografts showed more hydrophilic surfaces and PVP-I-sterilised tendons showed higher mechanical strength than Co60-sterilised tendons (P < 0.05). The level of residual PVP-I was higher without washing and with prolonged preservation (P < 0.05). In vitro cellular tests showed that appropriate PVP-I concentration was nontoxic to preosteoblast cells, and cellular differentiation measured by alkaline phosphatase activity and osteogenic gene markers was enhanced (P < 0.05). Therefore, the improved biological performance of implanted allografts may be attributable to better surface properties and residual PVP-I, and PVP-I immersion can be a simple, easy method for allograft sterilisation and preservation.

  1. [Effect of vitrification state of protective solutions on recovery of red blood cells after lyophilization preservation].

    PubMed

    Quan, Guo-Bo; Han, Ying; Liu, Xiu-Zhen; Liu, An; Jin, Peng; Cao, Wei

    2003-06-01

    To study effect of vitrification state of protective solutions on recovery of red blood cells after lyophilization, four protective solutions composed of isotonic buffers containing 7% DMSO (v/v) and 20%, 30%, 40% or 50% polyvinylpyrrolidone (PVP) (w/v) were adopted. Vitrification state of protective solutions was examined first when white ice crystal appeared in any protective solution during freezing or thawing, if the used solution was not a vitrification solution. Red blood cells were lyophilized in MINILYO45 freeze-dryer after washing, mixing with protective solutions and prefreezing. After lyophilization, the samples were quickly rehydrated by 37 degrees C rehydration solution. The results showed that in vitrification and devitrification experiments, white ice crystal appeared in solution of 20% PVP + 7% DMSO and 30% PVP + 7% DMSO during freezing and thawing; vitrification appeared in solution of 40% PVP + 7% DMSO during freezing, but devitrification appeared during thawing; vitrification appeared in solution of 50% PVP + 7% DMSO during freezing and thawing. After rehydration, the recoveries of red blood cells and hemoglobin in 40% PVP + 7% DMSO group were (81.36 +/- 14.94)% and (77.54 +/- 12.86)%, which were significantly higher than that in 20% PVP + 7% DMSO, 30% PVP + 7% DMSO and 50% PVP + 7% DMSO groups (P < 0.01). The concentration of free hemoglobin in 40% PVP + 7% DMSO group was also significantly lower than that in other three groups (P < 0.01). With increase of PVP concentration in protective solutions, vitrification state and protective effect of these solutions also increased; when concentration of PVP in protective solution was 40% though it was not a vitrification solution, the effect of lyophilization was the best; but when concentration of PVP further increased to 50%, though it was a vitrification solution, the effect decreased. It is concluded that excessive vitrification state could not benefit lyophilization of red blood cells.

  2. 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

  3. Evaluation of povidone-iodine as a disinfectant solution for contact lenses: antimicrobial activity and cytotoxicity for corneal epithelial cells.

    PubMed

    Yanai, Ryoji; Yamada, Naoyuki; Ueda, Kiichi; Tajiri, Motoharu; Matsumoto, Toru; Kido, Keiji; Nakamura, Shigeru; Saito, Fumio; Nishida, Teruo

    2006-05-01

    Povidone-iodine (PVP-I) possesses broad-spectrum antimicrobial activity and is used clinically as a disinfectant. We evaluated the disinfectant properties and safety of PVP-I for use as a contact lens solution. The concentrations of PVP-I required to reduce the number of Staphylococcus aureus or Candida albicans by 3 log units were lower than were those of hydrogen peroxide, polyhexamethylene biguanide (PHMB), and benzalkonium chloride (BAK). The cytotoxicity of PVP-I for cultured human corneal epithelial (HCE) cells was less than that of the other three agents. The safety margin for PVP-I was thus greatest among the tested compounds. PVP-I appears suited for use as a contact lens disinfectant.

  4. 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.

  5. Synthesis of alpha-chymotrypsin/polymer composites by a reverse micelle/gas antisolvent method.

    PubMed

    Li, Wei; Zhang, Jianling; Zhang, Chaoxing; Feng, Xiaoying; Han, Buxing; Yang, Guanying

    2007-09-01

    Alpha-chymotrypsin (CT)/polyvinylpyrrolidone (PVP) composites was synthesized by combination of reverse micelles and CO(2). In this method, the two reverse micellar solutions containing CT and PVP, respectively, were first mixed, then compressed CO(2) was used as an antisolvent to precipitate the CT and PVP simultaneously and CT/PVP composites were successfully prepared. The morphology of the obtained CT/PVP composites was characterized by transmission electron microscopy (TEM). The FTIR spectra of the composites showed that there was interaction between CT and PVP. The storage activity of the enzyme immobilized on the polymer by this method was higher than that of the pure enzyme. This method has some advantages and can be easily applied to the synthesis of some other enzyme/polymer composites.

  6. 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.

  7. Temperature scanning FTIR analysis of interactions between sugar and polymer additive in amorphous sugar-polymer mixtures.

    PubMed

    Imamura, Koreyoshi; Ohyama, Ken-Ichi; Yokoyama, Toru; Maruyama, Yoshinobu; Imanaka, Hiroyuki; Nakanishi, Kazuhiro

    2008-01-01

    The impact of a polymer additive (polyvinylpyrrolidone, PVP) on hydrogen bonding in amorphous sugar matrices as well as on the glass transition temperature, T(g), were examined by temperature scanning Fourier transform infrared spectroscopy (TS-FTIR). An amorphous sugar matrix containing PVP was prepared by air-drying an aqueous solution of a sugar-PVP mixture. The hydrogen bonds in the sugar-PVP mixture (sugar-PVP and sugar-sugar hydrogen bonds) were analyzed from the IR peak positions corresponding to the stretching vibration of C==O groups of PVP and O--H groups of the sugar and the temperature dependence of the peak position of the O--H stretching vibration band. The addition of PVP to amorphous mono and disaccharides significantly lowered the extent of hydrogen bond formation while interactions between sugars and the PVP tended to prevent the disruption of hydrogen bonds due to increasing temperature, the magnitude of which was larger for larger oligomers. The T(g) value for the amorphous sugar was increased by the addition of PVP in many cases. As the size of sugar molecule became larger, the relative magnitude of the increased T(g) by PVP to the difference between the T(g) values for sugar alone and PVP alone became larger and then reached a certain level; it was slight in the case of glucose. Collectively, these results demonstrate that the magnitude of the impact of PVP on an amorphous sugar matrix strongly vary and are dependent on the types of sugar. (c) 2007 Wiley-Liss, Inc.

  8. VEGF-Iron Oxide Conjugate for Dual MR and PET Imaging of Breast Cancer Angiogenesis

    DTIC Science & Technology

    2007-09-01

    iron oxide nanoparticles conjugated with macrocyclic chelating agent DOTA for 64Cu-labeling and cyclic RGD peptide for integrin alpha (v)beta(3...Nanoparticles We have developed two types of novel superparamagentic iron oxide nanoparticles (USPIO), namely, PVP -IO and PASP-IO...Polyvinylpyrrolidone ( PVP )-coated iron oxide ( PVP -IO) nanoparticles were synthesized by a one-step thermal decomposition method (Fig. 3). The overall size of the

  9. How to make hypericin water-soluble.

    PubMed

    Kubin, A; Loew, H G; Burner, U; Jessner, G; Kolbabek, H; Wierrani, F

    2008-04-01

    Hypericin, isolated from Hypericum perforatum, is an effective photodynamic substance as demonstrated by various studies. Practical forms of applications of hypericin solutions for systemic use and introduction into body cavities are, however, lacking. We developed an aqueous solution of hypericin non-covalently bound to polyvinylpyrrolidone (PVP). PVP is a poly-N-vinylamide of various degrees of polymerization and forms of intermolecular crosslinks suitable for diagnostic and therapeutic applications. We used PVP (molecular weights of PVP between 10 kD and 40 kD) as a complex forming agent to prepare hypericin for photodynamic therapy and diagnostics. In pure water, hypericin forms aggregates which are non-soluble and non-fluorescent. The hypericin-PVP complex binds more than 1000 mg of hypericin in presence of 100 g PVP or less and is soluble in 1 liter of pure water. Aqueous complex solutions of hypericin-PVP display a characteristic absorption spectrum and fluorescence emission band around 600 nm wavelength. Varying concentrations of hypericin do not cause a blue- or red-shift in the absorption maximum at 595 nm. Excitation at 200 nm to 500 nm leads to emission at 590 nm; a property conducive to diagnostic investigations both in vitro and in vivo. Furthermore, hypericin-PVP exhibits high photostability in the presence of oxygen and broad band light which ensures reproducible photodynamic therapy and diagnosis. Hypericin forms liquid molecular chromophore complexes in water when bound to PVP thus allowing investigations in biological media.

  10. Immobilization of povidone-iodine on surfaces of silica gel particles and bactericidal property.

    PubMed

    Gao, Baojiao; Wang, Zhanbin; Liu, Qing; Du, Ruikui

    2010-09-01

    A novel antibacterial material I(2)-PVP/SiO(2), on which povidone-iodine (PVP-I(2)) was loaded, was synthesized by a two-step route. Polyvinylpyrrolidone (PVP) was firstly graft-polymerized onto the surfaces of micro-sized silica gel particles, obtaining the grafted particles PVP/SiO(2). Subsequently, the grafted particles PVP/SiO(2) were allowed to undergo a complexation reaction with iodine, resulting in a water-insoluble antibacterial material, I(2)-PVP/SiO(2). The effects of various factors on the complexation reaction were examined. The antibacterial property of I(2)-PVP/SiO(2) was investigated by using Escherichia coli (E. coli) as model bacterium and with the colony count method. The experimental results show that the fitting temperature for the complexation reaction between PVP/SiO(2) and I(2) is 60 degrees C, and the complexation reaction reaches equilibrium after 12 h. The particles I(2)-PVP/SiO(2) have very strong antibacterial activity and they have the sterilizing mechanism similar to povidone-iodine. Copyright 2010 Elsevier B.V. All rights reserved.

  11. 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.

  12. Hydrodechlorination of chlorobenzene over polymer-stabilized palladium-platinum bimetallic colloidal nanocatalysts.

    PubMed

    Liu, Manhong; Wang, Chao; Yu, William W

    2010-11-01

    Poly(N-vinyl-2-pyrrolidone) (PVP)-stabilized Pd, Pt, Pd-Pt nanocatalysts were prepared and characterized by transmission electron microscopy (TEM). Hydrogenation of chlorobenzene was carried out over these colloidal nanocatalysts under ambient conditions. The catalytic properties for the hydrogenation of chlorobenzene depended on the composition of the bimetallic nanocatalysts. The conversion of chlorobenzene over PVP-Pd (83.64%) was higher than that of PVP-Pt (66.67%), which indicated that the activity of Pd was higher than that of Pt. In 10 hrs. the conversions of all the bimetallic nanocatalysts were higher than that of PVP-Pt (66.67%) monometallic nanocatalysts, and the maximum conversion of chlorobenzene (95.34%) was achieved using PVP-Pd/Pt = 1/1 catalytic system, which was much higher than that of the physical mixture of monometallic nanocatalysts (PVP-Pd and PVP-Pt) at the same Pd/Pt ratio as the PVP-Pd/Pt bimetallic nanocatalysts used. The selectivity to benzene and cyclohexane of the bimetallic nanocatalysts (with < or = 40 mol% Pt) was similar to that of PVP-Pd monometallic nanocatalysts, and nearly approximately 100% selectivity to benzene could be obtained, the selectivity to cyclohexane increased slowly with increasing of platinum content in bimetallic nanocatalysts.

  13. Biomaterial-associated persistence of Staphylococcus epidermidis in pericatheter macrophages.

    PubMed

    Boelens, J J; Dankert, J; Murk, J L; Weening, J J; van der Poll, T; Dingemans, K P; Koole, L; Laman, J D; Zaat, S A

    2000-04-01

    Biomaterial surfaces may be modified to reduce bacterial adhesion. The susceptibility in mice to Staphylococcus epidermidis infection in tissue surrounding the commonly used catheter materials-silicon elastomer (SE), polyamide (PA), and their surface-modified polyvinylpyrrolidone (PVP)-grafted derivatives, SE-PVP and PA-PVP, respectively-was assessed. Abscesses developed around SE-PVP. Around SE, PA, and PA-PVP catheters, no signs of infection were observed, although mice carrying PA-PVP developed septicemia after 14-21 days. S. epidermidis was cultured from the tissue surrounding PA-PVP segments. Cells around PA-PVP segments containing large numbers of bacteria were identified as macrophages by use of immunohistochemistry and electron microscopy. This persistence of intracellular bacteria was also observed around SE-PVP, SE, and PA catheters, although to a lesser extent. The cytokine profiles around the 4 materials were different. Implanted biomaterial induces an inflammatory response favorable to the persistence of S. epidermidis. Intracellular persistence of bacteria inside macrophages may be a pivotal process in the pathogenesis of biomaterial-associated infection.

  14. 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.

  15. Macrophage clearance of 125I-labelled polyvinyl pyrrolidone in the horse: effect of ovarian steroids and persistent endometritis.

    PubMed

    Watson, E D; Stokes, C R

    1988-11-01

    The rate of clearance of 125I-labelled polyvinyl pyrrolidone (PVP) from blood was measured in mares as an indicator of macrophage function. In three out of four cycling mares, PVP clearance was slower during oestrus than dioestrus. Similarly, administration of oestrogen to four ovariectomised mares tended to depress PVP clearance compared with clearance from the same mares before they received oestrogen. However, the effect of oestrogen was not statistically significant. Mares susceptible to persistent endometritis had rates of PVP clearance which were similar to those of genitally normal mares.

  16. Separation of iron and cobalt using 59Fe and 60Co by dialysis of polyvinylpyrrolidone-metal complexes: a greener approach.

    PubMed

    Lahiri, Susanta; Sarkar, Soumi

    2007-04-01

    An environmentally benign method to separate iron and cobalt has been developed using a safe chemical, polyvinylpyrrolidone (PVP). The method involves dialysis of PVP-Fe and PVP-Co complexes against triple-distilled water. (59)Fe and (60)Co were used as radioactive tracers of iron and cobalt throughout the experiment. No other chemicals are required for clean separation of cobalt from iron. The optimum condition for separation has been obtained at pH 5 using 10% aqueous solution of PVP. The method is applicable from trace scale to macro-scale. Very high separation factors have been obtained.

  17. Biofilm formation on coated silicone tympanostomy tubes.

    PubMed

    Ojano-Dirain, Carolyn P; Silva, Rodrigo C; Antonelli, Patrick J

    2013-02-01

    Tympanostomy tube (TT) surface modifications have been promoted as a means of reducing biofilm formation, otorrhea, and occlusion. The goal of this study was to determine if biofilm formation on silicone TTs could be prevented by commercially available surface coatings. Silicone TTs with and without polyvinylpyrrolidone (PVP) or/and silver oxide were exposed to human plasma and cultured with Pseudomonas aeruginosa or Staphylococcus aureus (22 TTs per group). After 4 days, antibiotics were added to kill planktonic bacteria. Biofilm formation was assessed by quantitative bacterial counts and scanning electron microscopy. PVP, silver, and PVP-silver coatings reduced P. aeruginosa biofilm formation relative to silicone by over 1 log (p<0.0001). PVP was superior to silver (p=0.04) and PVP-silver (p<0.0001). PVP and PVP-silver coatings increased S. aureus biofilm formation nominally (p=0.01 & 0.003). PVP and silver coatings reduce P. aeruginosa biofilm formation on silicone TTs. Combining PVP and silver coatings does not further improve biofilm resistance. TT surface coatings warrant further study through clinical trials. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

  18. Physicochemical and functional characterization of the collagen-polyvinylpyrrolidone copolymer.

    PubMed

    Leyva-Gómez, Gerardo; Lima, Enrique; Krötzsch, Guillermo; Pacheco-Marín, Rosario; Rodríguez-Fuentes, Nayeli; Quintanar-Guerrero, David; Krötzsch, Edgar

    2014-08-07

    Collagen-polyvinylpyrrolidone (C-PVP) is a copolymer that is generated from the γ irradiation of a mixture of type I collagen and low-molecular-weight PVP. It is characterized by immunomodulatory, fibrolytic, and antifibrotic properties. Here, we used various physicochemical and biological strategies to characterize the structure, biochemical susceptibility, as well as its effects on metabolic activity in fibroblasts. C-PVP contained 16 times more PVP than collagen, but only 55.8% of PVP was bonded. Nevertheless, the remaining PVP exerted strong structural activity due to the existence of weak bonds that provided shielding in the NMR spectra. On SEM and AFM, freeze-dried C-PVP appeared as a film that uniformly covered the collagen fibers. Size analysis revealed the presence of abundant PVP molecules in the solution of the copolymer with a unique dimension related to macromolecular combinations. Calorimetric analysis showed that the copolymer in solution exhibited structural changes at 110 °C, whereas the lyophilized form showed such changes at temperatures below 50 °C. The copolymer presented a rheopectic behavior, with a predominant effect of the collagen. C-PVP had biological effects on the expression of integrin α2 and prolyl-hydroxylase but did not interact with cells through the collagen receptors because it did not inhibit or slow contraction.

  19. Self-diffusion of Asymmetric Diblock Copolymers with a Spherical Domain Structure

    NASA Astrophysics Data System (ADS)

    Yokoyama, H.; Kramer, E. J.

    1997-03-01

    The molecular weight and temperature dependence of the self-diffusion coefficient D of spherically ordered asymmetric diblock copolymers of deuterated polystyrene-b-2vinylpyridine (dPS-PVP) in protonated hPS-PVP has been investigated using forward recoil spectrometry (FRES). In cases where the product of the number of segments of the PVP core block, N_PVP, and the interaction parameter, \\chi, exceeds roughly 10, D is much smaller than that of a homopolystyrene with the same molecular weight and D decreases exponentially with N_PVP. The temperature dependence of D is different from WLF, reflecting instead the temperature dependence of \\chi(T) in D = Aexp(-α\\chiN_PVP) where A and α are constants. On the other hand, when \\chiN_PVP is about 5, we did not observe a significant difference between D of the block copolymer and that of homopolystyrene. At this \\chiN_PVP, as well as at all larger values, an ordered spherical morphology is observed by TEM. The diffusion process at high \\chiN_PVP is thought to involve an thermally activated "hopping" mechanism in which single block copolymer chains diffuse by hopping from one spherical domain to another.

  20. Dynamic cross-linking effect of Mg2+ to enhance sieving properties of low-viscosity poly(vinylpyrrolidone) solutions for microchip electrophoresis of proteins.

    PubMed

    Mohamadi, Mohamad Reza; Kaji, Noritada; Tokeshi, Manabu; Baba, Yoshinobu

    2008-01-01

    We report a dynamic cross-linking effect of Mg2+ that enhances the sieving properties of low-viscosity poly(vinylpyrrolidone) (PVP) solutions. A low-viscosity PVP solution was applied to nondenaturing microchip electrophoresis of protein samples using microchips made of poly(methyl methacrylate). The separation resolution of nondenatured protein markers in 1.8% PVP solution was improved by adding 1-20 mM MgCl2. We studied the effect of the ratio of cross-linking agent on mobility of protein samples and showed that protein retardation (ln micro/micro0) is correlated with the ratio of cross-linking agent to PVP ([cMg2+/cPVP]) as ln micro/micro0=A'[cMg2+/cPVP]b'. A' was related to the protein radius (R), and b' was found to be 0.72 for proteins with R=2.4 nm and 0.82 for proteins with R=1.85 nm. A structural study of PVP in semidilute solutions using dynamic light scattering showed that incremental increases of Mg2+ ion concentration from 5 to 20 mM in 1.8% PVP solution increased the hydrodynamic radius of PVP polymers by 20%.

  1. Induction of apoptosis and cell cycle arrest by polyvinylpyrrolidone K-30 and protective effect of alpha-tocopherol.

    PubMed

    Wang, Yu-Bao; Lou, Yang; Luo, Zhao-Feng; Zhang, Dong-Fang; Wang, Yu-Zhen

    2003-09-05

    Polyvinylpyrrolidone is a macromolecular polymer with widespread use in industry as well as in medicine for various purposes. Its effect on cells cultured in vitro, however, has not been fully investigated. To elucidate this issue, we studied the influence of PVP K-30 on cultured HeLa cells. PVP K-30 treatment produced a dose- and time-dependent toxicity to HeLa cells. Cells exposed to PVP K-30 exhibited several morphological features of apoptosis. Gel electrophoresis of DNA from PVP K-30-treated cells showed typical apoptotic ladder. And flow cytometric analysis demonstrated that PVP K-30 induced cell cycle arrest at G2/M phase and the subsequent appearance of sub-G1 population. In addition, it was shown that procaspase-3 was activated in response to PVP K-30 treatment. We also found that alpha-tocopherol efficiently protected HeLa cells from PVP K-30 cytotoxicity. This is the first demonstration that PVP K-30 could induce apoptosis in HeLa cells and cell cycle arrest at G2/M phase, and that PVP K-30 toxicity could be attenuated by alpha-tocopherol.

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

    PubMed

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

    2017-10-01

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

  3. Posthepatectomy portal vein pressure predicts liver failure and mortality after major liver resection on noncirrhotic liver.

    PubMed

    Allard, Marc-Antoine; Adam, René; Bucur, Pétru-Octav; Termos, Salah; Cunha, Antonio Sa; Bismuth, Henri; Castaing, Denis; Vibert, Eric

    2013-11-01

    To evaluate the predictive value of portal vein pressure (PVP) after major liver resection for posthepatectomy liver failure (PLF) and 90-day mortality in patients without cirrhosis. As elevated PVP is associated with liver failure after living donor liver transplantation, we hypothesized that the outcome after major hepatectomy may be influenced by posthepatectomy PVP. All patients without severe fibrosis or cirrhosis who underwent a major liver resection (≥3 segments) with an intraoperative measurement of PVP at the end of the procedure were included. Outcome was analyzed regarding 3 most widely used definitions of PLF: "50-50" criteria, peak of serum bilirubin greater than 120 μmol/L, and grade C PLF proposed by the International Study Group of Liver Surgery (ISGLS). Receiver operating characteristic curves and logistic regression model were used to determine the optimal cutoff of PVP and independent risk factors of PLF. The study population consisted of 277 patients. Posthepatectomy PVP was gradually correlated with the PLF risk. Probability for PLF was nil when PVP was 10 mm Hg or less, ranges from 13% to 16%, depending on PLF definitions, when PVP was 20 mm Hg, and from 24% to 33% when PVP was 30 mm Hg. The optimal value of posthepatectomy PVP to predict PLF was 22 mm Hg when considering the "50-50" criteria and grade C PLF (proposed by the International Study Group of Liver Surgery). A value of 21 mm Hg best predicted PLF defined by peak of serum bilirubin greater than 120 μmol/L and 90-day mortality. At multivariate analysis, posthepatectomy PVP remained an independent predictor of PLF as well as the extent of resection, intraoperative transfusion, and the presence of diabetes. The 90-day mortality was associated with PVP greater than 21 mm Hg, older than 70 years, and intraoperative transfusion. Posthepatectomy PVP is an independent predictive factor of PLF and of 90-day mortality after major liver resection in patients without cirrhosis

  4. Synthesis, characterization and chemistry of platinum and iridium nanoparticles in solution and nanoporous silicas

    NASA Astrophysics Data System (ADS)

    Jagassar, Parbatee Samaroo

    This project focuses on the synthesis of catalytically-active, transition-metal nanoparticles, their adsorption into porous Vycor glass (PVG), the removal of the poly(vinylpyrrolidone) (PVP) surfactant employed in their synthesis and their chemistry with Ru(II) diimine complexes. Platinum and iridium nanoparticles with a narrow size distribution were prepared by the alcohol reduction method with poly(vinylpyrrolidone) (PVP) as the size limiting surfactant. PVP/Pt nanoparticles adsorb into PVG and as much as 46 ± 4% of the PVP can be removed without further nanoparticle aggregation. XANES spectra show that removal of the PVP surfactant occurs without oxidation of the Pt nanoparticle. EXAFS of the adsorbed Pt nanoparticles after removal of the PVP yield a Pt-Pt bond length of 2.74 ± 0.01 Å which is slightly shorter than the Pt-Pt bond length measured in Pt foil, 2.78 Å. We have shown that the Pt nanoparticles, both the stripped and the unstripped of PVP in porous Vycor glass, does not influence their reactivity with either the [Ru(bpy)2 dpp]2+ or the [Ru(bpy)2ppz]2+ complexes. The addition of PVP/Pt or PVP/Ir nanoparticles to aqueous-ethanol solutions of [Ru(bpy)2ppz]2+ (ppz denotes 4,7-phenanthro-lino-5:6,5'6'pyrazine) leads to the spontaneous aggregation of the nanoparticles about the complex. A comparison of the aggregation about different Ru(II) diimines indicates aggregation initiates at the heteroleptic ligand. Although initiating at the ppz ligand, continued aggregation of the nanoparticles about the complex dilutes the specificity of the initial interaction leading to larger aggregates of differing shape. TEM analyses of the aggregates indicate the volume occupied by the individual nanoparticles is a small fraction of the total volume of the aggregate suggesting a somewhat open structure interlaced with the solvent. Correlating TEM analyses of the aggregation with the electronic spectra of the solutions reveals a new absorption assigned to the formation

  5. Intracellular localization and toxicity of graphene oxide and reduced graphene oxide nanoplatelets to mussel hemocytes in vitro.

    PubMed

    Katsumiti, Alberto; Tomovska, Radmila; Cajaraville, Miren P

    2017-07-01

    Recently, graphene materials have attracted tremendous research interest due to their unique physicochemical properties that hold great promise in electronics, energy, materials and biomedical areas. Graphene oxide (GO) is one of the most extensively studied graphene derivatives. In order to improve GO electrical properties, nanoplatelets are chemically reduced, thus increasing nanoplatelet conductivity. This reduced GO (rGO) shows different properties and behavior compared to GO. Graphene-based wastes are expected to end up in the marine environment. Here we aimed to assess the potential toxic effects of GO and rGO to marine organisms by using in vitro assays with mussel (Mytilus galloprovincialis) hemocytes. Cells were exposed to a wide range of concentrations (up to 100mg/L) of GO (with and without polyvinylpyrrolidone-PVP as stabilizing agent: GO and GO-PVP) and rGO with PVP (rGO-PVP) to assess cytotoxicity and cell membrane integrity. Then, cells were exposed to sublethal concentrations of GO and rGO-PVP to assess their subcellular distribution through transmission electron microscopy (TEM) and to evaluate their effects on ROS production. GO, GO-PVP and rGO-PVP showed low and concentration-dependent cytotoxicity. rGO-PVP (LC50=29.902 and 33.94mg/L depending on the origin) was more toxic than GO (LC50=49.84 and 54.51mg/L depending on the origin) and GO-PVP (LC50=43.72mg/L). PVP was not toxic to hemocytes but increased bioavailability and toxicity of nanoplatelets. At TEM, GO and rGO-PVP nanoplatelets caused invaginations and perforations of the plasma membrane, which agrees with the observed decrease in cell membrane integrity. Nanoplatelets were internalized, at a higher extent for rGO-PVP than for GO, and found in the cytosol and in endolysosomal vesicles of hemocytes. Both GO and rGO-PVP increased ROS production at the highest sublethal concentration tested. In conclusion, GO, GO-PVP and rGO-PVP are not highly toxic to mussel cells but they cause membrane

  6. 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.

  7. 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.

  8. 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

  9. 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...

  10. 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.

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

    PubMed

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

    2016-11-01

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

  12. 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%.

  13. 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...

  14. 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...

  15. 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...

  16. Complexes of poly-N-vinylpyrrolidone with sulfonated tetraphenylporphins

    SciTech Connect

    Kulvelis, Yu. V. Lebedev, V. T.; Toeroek, Gy.; Klyubin, V. V.

    2007-05-15

    The interaction of sulfonated tetraphenylporphins H{sub 2}TPPS{sub 4}(HCl){sub 2} and in CuTPPS{sub 4} with poly-N-vinylpyrrolidone (PVP) is studied using small-angle neutron scattering, dynamic light scattering, visible spectrophotometry, and viscometry. It is shown that porphyrin molecules form complexes with PVP, thus charging the polymeric chain.

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

    USDA-ARS?s Scientific Manuscript database

    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...

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

    USDA-ARS?s Scientific Manuscript database

    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...

  19. The cubic phase of phosphatidylethanolamine film by small angle x-ray scattering

    NASA Astrophysics Data System (ADS)

    Sun, Run Guang; Zhang, Jing

    2004-02-01

    Using small angle x-ray scattering, we have investigated the effects of polyvinylpyrrolidone (PVP) and oleic acid (OA) on the structures of the cubic phase of 1,2-dielaidoyl-sn-glycero-3-phosphoethanolamine (DEPE) films. At lower PVP concentrations, DEPE-PVP mixed films existed in two cubic phases. With increasing PVP concentration in the DEPE-PVP mixed phase, a phase transition from Q229 (Im3m) to Q224 (Pn3m) occurred. The effect of addition of OA to a DEPE-PVP mixed phase was also determined using a certain fixed amount. At 0.5 mol% OA, the presence of low amounts of OA allows the DEPE-PVP-OA system to organize in a cubic Q229 phase. At 1.0 mol% OA, the presence of larger amounts of OA induces formation of coexisting Q229 and Q224 phases. At 1.5 mol% OA, the presence of even larger amounts of OA promotes formation of a cubic Q224 phase in the DEPE-PVP-OA mixture.

  20. 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

  1. 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.

  2. A Novel Predictor of Posttransplant Portal Hypertension in Adult-To-Adult Living Donor Liver Transplantation: Increased Estimated Spleen/Graft Volume Ratio

    PubMed Central

    Gyoten, Kazuyuki; Mizuno, Shugo; Kato, Hiroyuki; Murata, Yasuhiro; Tanemura, Akihiro; Azumi, Yoshinori; Kuriyama, Naohisa; Kishiwada, Masashi; Usui, Masanobu; Sakurai, Hiroyuki; Isaji, Shuji

    2016-01-01

    Background In adult living donor liver transplantation (ALDLT), graft-to-recipient weight ratio of less than 0.8 is incomplete for predicting portal hypertension (>20 mm Hg) after reperfusion. We aimed to identify preoperative factors contributing to portal venous pressure (PVP) after reperfusion and to predict portal hypertension, focusing on spleen volume-to-graft volume ratio (SVGVR). Methods In 73 recipients with ALDLT between 2002 and 2013, first we analyzed survival according to PVP of 20 mm Hg as the threshold, evaluating the efficacy of splenectomy. Second, we evaluated various preoperative factors contributing to portal hypertension after reperfusion. Results All of the recipients with PVP greater than 20 mm Hg (n = 19) underwent PVP modulation by splenectomy, and their overall survival was favorable compared with 54 recipients who did not need splenectomy (PVP ≤ 20 mm Hg). Graft-to-recipient weight ratio had no correlation with PVP. Multivariate analysis revealed that estimated graft and spleen volume were significant factors contributing to PVP after reperfusion (P < 0.0001 and P < 0.0001, respectively). Furthermore, estimated SVGVR showed a significant negative correlation to PVP after reperfusion (R = 0.652), and the best cutoff value for portal hypertension was 0.95. Conclusions In ALDLT, preoperative assessment of SVGVR is a good predictor of portal hypertension after reperfusion can be used to indicate the need for splenectomy before reperfusion. PMID:27472097

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

    PubMed

    Patel, Dhaval D; Anderson, Bradley D

    2015-09-01

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

  4. Effects of successive additions of two capping ligands on the structural properties of PbO nanoparticles

    NASA Astrophysics Data System (ADS)

    Bangi, Uzma K. H.; Han, Wooje; Yoo, Byungwook; Park, Hyung-Ho

    2013-11-01

    A cost-effective approach to the synthesis of lead oxide (PbO) nanoparticles by successive additions of two capping ligands using a simple method of precipitation is reported herein. The successive additions of polyvinyl pyrrolidone (PVP) and cetyltrimethyl ammonium bromide (CTAB) cap the Pb(OH)2 with a primary layer of PVP and a secondary layer of CTAB, forming a bilayer system around Pb(OH)2. PVP controls the PbO particle size, while CTAB enhances the particle size of the PVP-treated PbO by seeding growth process. The effects of the successive additions of these two capping ligands were studied by varying the relative percentages of PVP and CTAB from 0 to 100 %. From transmission electron microscopy and X-ray diffraction results, it was confirmed that the size of the PbO nanoparticles decreased with a relative increase in the percentage of PVP (and corresponding decrease in the percentage of CTAB). Furthermore, X-ray diffraction results demonstrated the formation of a pure α-PbO phase. Field emission scanning electron microscopy images showed the increase in grain size with the decrease in the percentage of PVP. Infrared spectroscopy depicted the formation of PbO along with the presence of PVP and CTAB covering the particle surface. Thermogravimetric analysis and differential thermal analysis revealed the decomposition of lead oxalate to α-PbO at around 370 °C.

  5. Cooperative hydrogen bonds of macromolecules. 2. Two-dimensional cooperativity in the binding of poly(4-vinylpyridine) to poly(4-vinylphenol).

    PubMed

    Kríz, Jaroslav; Dybal, Jirí; Brus, Jirí

    2006-09-21

    The hydrogen bond interaction of poly(4-vinylphenol) (PVF), ligated by a 20 mol/mol excess of pyridine-d(5) (PD) in tetrahydrofuran-d(8), with poly(4-vinylpyridine) (PVP) was studied using liquid and solid-state NMR and quantum mechanical calculations. Because of its cooperative interaction, PVP substitutes PD in its hydrogen bond with PVF, thus forming a PVF-PVP complex, which gradually precipitates from solution. On the basis of the 1H/13C NMR spin-diffusion experiments and density functional theory quantum calculations, the complex is shown to have the fairly regular structure of a polymer sheet with intermittent H-bond links between PVF and PVP chains. The cooperativity of PVP interaction with PVF was studied by measuring the dependence of the binding degree alpha of PVP on its polymerization degree (P(n), being 10, 17, 30, 36, 48, 65, and 84) at various PVP/PVF molar ratios. The value of alpha was established indirectly by measuring the fraction of liberated PD using its 2H quadrupolar relaxation and pulsed field-gradient spin-echo measurement of self-diffusion. The cooperativity is shown to be of a higher order and two-dimensional, that is, dependent on both the polymerization degree of PVP and its ratio to PVF. A mathematical model of such two-dimensional cooperativity based chiefly on a proximity effect is suggested.

  6. [Relevance of an iodine allergy to commercial polyvidone-iodine preparations].

    PubMed

    Kunze, J; Kaiser, H J; Petres, J

    1983-02-15

    Patch testing with Iodine/potassium-iodide (3%) and commercialized povidone (PVP)-iodine preparations (Betaisodona-ointment and solution, Polyvidon-Jod-ointment "Braun", Braunol-solution "Braun", Traumasept-ointment, and Traumasept solution--not marketed--, were carried out in 104 patients of the Department of Dermatology of the Municipal Hospital Kassel. In addition, the according ointment and solution-bases were tested. 22 tests were patients with ulcera crurum, 82 patients with infectious skin diseases or skin tumors. 35 out of the 104 patients showed positive reactions to iodine/potassium-iodide. Hyperreactivity to one or more PVP-iodine-ointments was found in 12 patients, to one or more PVP-iodine solutions in 29 patients. If there was no positive reaction to iodine/potassium-iodide, PVP-iodine ointments were always tolerated, while PVP-iodine-solutions produced positive reactions in 9 cases even then. Our results show that allergic skin reactions must be expected in 2-9% of all patients using PVP-iodine ointments, and in 12-20% of all patients using PVP-iodine-solutions. If iodine-allergy is known the rate of positive reactions to PVP-iodine ointments is 6-25% to the solutions 34-60%.

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

    PubMed

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

    2010-12-28

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

  8. A comparison of spray drying and milling in the production of amorphous dispersions of sulfathiazole/polyvinylpyrrolidone and sulfadimidine/polyvinylpyrrolidone.

    PubMed

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

    2011-04-04

    Formulations containing amorphous active pharmaceutical ingredients (APIs) present great potential to overcome problems of limited bioavailability of poorly soluble APIs. In this paper, we directly compare for the first time spray drying and milling as methods to produce amorphous dispersions for two binary systems (poorly soluble API)/excipient: sulfathiazole (STZ)/polyvinylpyrrolidone (PVP) and sulfadimidine (SDM)/PVP. The coprocessed mixtures were characterized by powder X-ray diffraction (PXRD), differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR) and intrinsic dissolution tests. PXRD and DSC confirmed that homogeneous glassy solutions (mixture with a single glass transition) of STZ/PVP were obtained for 0.05 ≤ X(PVP) (PVP weight fraction) < 1 by spray drying and for 0.6 ≤ X(PVP) < 1 by milling (at 400 rpm), and homogeneous glassy solutions of SDM/PVP were obtained for 0 < X(PVP) < 1 by spray drying and for 0.7 ≤ X(PVP) < 1 by milling. For these amorphous composites, the value of T(g) for a particular API/PVP ratio did not depend on the processing technique used. Variation of T(g) versus concentration of PVP was monotonic for all the systems and matched values predicted by the Gordon-Taylor equation indicating that there are no strong interactions between the drugs and PVP. The fact that amorphous SDM can be obtained on spray drying but not amorphous STZ could not be anticipated from the thermodynamic driving force of crystallization, but may be due to the lower molecular mobility of amorphous SDM compared to amorphous STZ. The solubility of the crystalline APIs in PVP was determined and the activities of the two APIs were fitted to the Flory-Huggins model. Comparable values of the Flory-Huggins interaction parameter (χ) were determined for the two systems (χ = -1.8 for SDM, χ = -1.5 for STZ) indicating that the two APIs have similar miscibility with PVP. Zones of stability and instability of the amorphous dispersions

  9. Genistein Modified Polymer Blends for Hemodialysis Membranes

    NASA Astrophysics Data System (ADS)

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

    2012-02-01

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

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

    PubMed

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

    2013-12-01

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

  11. Recent Developments in Shape-Controlled Synthesis of Silver Nanocrystals

    PubMed Central

    Xia, Xiaohu; Zeng, Jie; Zhang, Qiang; Moran, Christine H.; Xia, Younan

    2012-01-01

    This feature article introduces our recent work on understanding the roles played by citrate and poly(vinyl pyrrolidone) (PVP) as capping agents in seed-mediated syntheses of Ag nanocrystals with controlled shapes. We have demonstrated that citrate and PVP selectively bind to Ag(111) and Ag(100) surfaces, respectively, and thus favor the formation of Ag nanocrystals enclosed preferentially by {111} or {100} facets. In addition, we have quantified the coverage density of PVP adsorbed on the surface of Ag nanocubes. Based on the mechanistic understanding, a series of Ag nanocrystals with controlled shapes and sizes have been successfully synthesized by using different combinations of seeds and capping agents: single-crystal spherical/cubic seeds with citrate for cuboctahedrons and octahedrons or with PVP for cubes and bars; and plate-like seeds with citrate for enlarged thin plates or with PVP for thickened plates. PMID:23105955

  12. The tracking of interfacial interaction of amorphous solid dispersions formed by water-soluble polymer and nitrendipine

    NASA Astrophysics Data System (ADS)

    Li, Jing; Fan, Na; Li, Chang; Wang, Jian; Li, Sanming; He, Zhonggui

    2017-10-01

    Herein, interfacial interactions of amorphous solid dispersion formed by nitrendipine (TDP) and two types of water-soluble polymers (polyvinyl pyrrolidone K30 (PVP) and polyethylene glycol 6000 (PEG)) were tracked mainly concerning with interaction forces and wetting process. Infrared spectroscopy (IR), raman spectroscopy and contact angle instrument were mainly used through the study. Hydrogen bonding forces were formed between drug and excipient in TDP-PVP and TDP-PEG. The red raman shift of TDP-PVP and TDP-PEG confirmed the hydrogen bonding forces between TDP and the two polymers. Both TDP-PVP and TDP-PEG showed higher drug release and TDP-PVP accomplished TDP release faster due to its better drug amorphous state. It is believed that the track of interfacial interactions will certainly become powerful tools to provide valuable instruction for designing and evaluating amorphous solid dispersions.

  13. Plasmonic core-shell metal-organic nanoparticles enhanced dye-sensitized solar cells.

    PubMed

    Xu, Qi; Liu, Fang; Meng, Weisi; Huang, Yidong

    2012-11-05

    We present an investigation on introducing core-shell Au@PVP nanoparticles (NPs) into dye-sensitized solar cells. As a novel core-shell NPs structure, Au@PVP present not only the chemical stability to iodide/triiodide electrolyte, but also the adhesiveness to dye molecules, which could help to localize most of dye molecules around plasmonic NPs, hence increasing the optical absorption consequently the power conversion efficiency (PCE) of the device. We obtain a PCE enhancement of 30% from 3.3% to 4.3% with incorporation of Au@PVP NPs. Moreover, the device performance with different concentration of Au@PVP NPs from 0 to 12.5 wt% has been studied, and we draw the conclusion that the performance of DSCs could be well improved through enhancing the light absorption by local surface plasmon (LSP) effect from Au@PVP NPs with an optimized concentration.

  14. Using polyvinylpyrrolidone to enhance the enzymatic hydrolysis of lignocelluloses by reducing the cellulase non-productive adsorption on lignin.

    PubMed

    Cai, Cheng; Qiu, Xueqing; Zeng, Meijun; Lin, Meilu; Lin, Xuliang; Lou, Hongming; Zhan, Xuejuan; Pang, Yuxia; Huang, Jinhao; Xie, Lingshan

    2017-03-01

    Polyvinylpyrrolidone (PVP) is an antifouling polymer to resist the adsorption of protein on solid surface. Effects of PVP on the enzymatic hydrolysis of pretreated lignocelluloses and its mechanism were studied. Adding 1g/L of PVP8000, the enzymatic digestibility of eucalyptus pretreated by dilute acid (Eu-DA) was increased from 28.9% to 73.4%, which is stronger than the classic additives, such as PEG, Tween and bovine serum albumin. Compared with PEG4600, the adsorption of PVP8000 on lignin was larger, and the adsorption layer was more stable and hydrophilic. Therefore, PVP8000 reduced 73.1% of the cellulase non-productive adsorption on lignin and enhanced the enzymatic hydrolysis of lignocelluloses greatly. Copyright © 2016 Elsevier Ltd. All rights reserved.

  15. 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.

  16. 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.

  17. Percutaneous vertebroplasty guided by preoperative computed tomography measurements

    PubMed Central

    Tan, Zhongbao; Di, Zhenhai; Mao, Xuequn; Zhang, Jian; Zou, Rong; Wang, Qingqing

    2016-01-01

    Background: Percutaneous vertebroplasty (PVP) is now widely performed to treat painful vertebral compression fractures. Previous researches have reported numerous advantages. However, it rarely reported that how to determine the feasibility of the unilateral or bilateral approach and how to decide the puncture angle, the skin insertion site before the procedure. The aim of this study was to discuss the feasibility of PVP using unilateral pedicular approach by the three-dimensional positioning of computed tomography (CT) image. Materials and Methods: Under fluoroscopic guidance, 108 patients with 115 diseased vertebral bodies underwent PVP. The study was divided in two groups. Group A, fifty patients with 52 vertebrae received PVP without using preoperative CT measurements and puncture simulation. Group B, 58 patients with 63 vertebrae received PVP using preoperative CT measurements and puncture simulation. The skin needle entry point and puncture angle of the transverse plane and sagittal plane were determined by the software of PACS on preoperative CT image. The choice of unilateral or bilateral pedicular approach was decided based on the CT image before the procedure. PVP was carried out according to the measurement result above. The average time for a single vertebra operation, the success rate of single puncture and complications was evaluated and compared between Group A and Group B. Results: In Group A, technical success of unilateral PVP was 63.5% (33/52 vertebrae), and 92% (58/63 vertebrae) in Group B. The average time of operation in Groups A and B were (37.5 ± 5.5) and (28.5 ± 5.5) min, respectively. There was a significant difference in the time of single-vertebra operation and the success rates of unilateral PVP between Groups A and B. No serious complications developed during the followup period. Conclusions: The CT three-dimensional positioning measurement for PVP can increase the success rate of unilateral PVP. PMID:27904217

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

    NASA Astrophysics Data System (ADS)

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

    2014-02-01

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

  19. Neuropsychological outcome after unilateral pallidotomy for the treatment of Parkinson's disease

    PubMed Central

    Rettig, G.; York, M.; Lai, E.; Jankovic, J.; Krauss, J.; Grossman, R.; Levin, H.

    2000-01-01

    OBJECTIVE—To assess the long term cognitive outcome of unilateral posteroventral pallidotomy (PVP) and the overall efficacy of the surgery.
METHODS—Forty two (29 left and 13 right PVP) patients with Parkinson's disease underwent neurological and neuropsychological testing before PVP and at 3 and 12 months after PVP. The neuropsychological testing battery emphasised measures of verbal learning and memory, visuospatial abilities, speed of information processing, executive functioning, and affective functioning.
RESULTS—All patients demonstrated motor improvements after surgery during their off state, and 86% of patients also showed improvements in motor functioning in their on state. Repeated measures ANOVA showed significant improvements in confrontational naming, visuospatial organisation, and affective functioning 3 months and 12 months after surgery, with inconsistent improvements in executive functioning 12 months post-PVP. Patients demonstrated a transient impairment in verbal memory, with verbal learning performance returning to baseline 12 months post-PVP after a significant decline 3 months after PVP. When three patients with lesions extending outside of the PVP were excluded from the analysis, a decline in verbal fluency performance after PVP was not found to be significant. Differences due to side of lesion placement were not found on any of the cognitive measures.
CONCLUSIONS—In the largest long term follow up study reported to date, the cognitive changes found up to a year after PVP are minimal compared with the robust improvements in motor function. The findings highlight the need to investigate the relation between the specific fibre tracts affected by the lesions and cognitive outcome.

 PMID:10945807

  20. Antitumor activity of tumor necrosis factor-alpha conjugated with polyvinylpyrrolidone on solid tumors in mice.

    PubMed

    Kamada, H; Tsutsumi, Y; Yamamoto, Y; Kihira, T; Kaneda, Y; Mu, Y; Kodaira, H; Tsunoda, S I; Nakagawa, S; Mayumi, T

    2000-11-15

    We attempted the development of a novel polymer conjugation to further improve the therapeutic potency of antitumor cytokines compared with PEGylation for clinical application. Compared with native tumor necrosis factor (TNF)-alpha in vitro, specific bioactivities of polyvinyl-pyrrolidone (PVP)-modified TNF-alphas (PVP-TNF-alphas) were decreased by increasing the degree of PVP attachment. PVP-TNF-alpha fraction 3, Mr 101,000, had the most effective antitumor activity of the various PVP-TNF-alphas in vivo. PVP-TNF-alpha fraction 3 had >200-fold higher antitumor effect than native TNF-alpha, and the antitumor activity of PVP-TNF-alpha fraction 3 was >2-fold higher than that of MPEG-TNF-alpha (Mr 108,000), which had the highest antitumor activity among the polyethylene glycol (PEG)-conjugated TNF-alphas. Additionally, a high dose of native TNF-alpha induced toxic side effects such as body weight reduction, piloerection. and tissue inflammation, whereas no side effects were observed after i.v. administration of PVP-TNF-alpha fraction 3. The plasma half-life of PVP-TNF-alpha fraction 3 (360 min) was about 80- and 3-fold longer than those of native TNF-alpha (4.6 mm) and MPEG-TNF-alpha (122 min), respectively. The mechanism of increased antitumor effect in vivo caused the prolongation of plasma half-life and increase in stability. These results suggested that PVP is a useful polymeric modifier for bioconjugation of TNF-alpha to increase its antitumor potency, and multifunctionally bioconjugated TNF-alpha may be a potentiated antitumor agent for clinical use.

  1. Molecular design of conjugated tumor necrosis factor-alpha: synthesis and characteristics of polyvinyl pyrrolidone modified tumor necrosis factor-alpha.

    PubMed

    Kamada, H; Tsutsumi, Y; Tsunoda, S; Kihira, T; Kaneda, Y; Yamamoto, Y; Nakagawa, S; Horisawa, Y; Mayumi, T

    1999-04-13

    We conjugated tumor necrosis factor-alpha (TNF-alpha) with the synthetic polymeric modifier polyvinyl pyrrolidone (PVP) to facilitate its clinical use for anti-tumor therapy. TNF-alpha was chemically conjugated with the terminal carboxyl-bearing PVP at one end of its main chain, which was radically polymerized via the formation of an amide bond between the lysine amino groups of TNF-alpha and carboxyl group of PVP. In vitro specific bioactivity of PVP-conjugated TNF-alpha (PVP-TNF-alpha) relative to that of native TNF-alpha gradually decreased with increases in the degree of PVP attachment. In contrast, PVP-TNF-alpha in which 40% of TNF-alpha lysine residues were coupled with PVP (MPVP-TNF-alpha) exhibited the highest anti-tumor activity among the conjugated derivatives examined. MPVP-TNF-alpha had more than 200-fold higher anti-tumor efficacy than native TNF-alpha, and the anti-tumor activity of MPVP- TNF-alpha was more than 5-fold stronger than that MPEG- TNF-alpha which had the highest anti-tumor activity among PEG-conjugated TNF-alphas examined. Additionally, a high dose of native TNF-alpha induced toxic side-effects such as body weight reduction, piloerection and tissue inflammation, while no side effects were observed following i.v. administration of MPVP-TNF-alpha. The plasma half-life of MPVP-TNF-alpha (360 min) was about 80 and 3-fold longer than those of native TNF-alpha (4.6 min) and MPEG-TNF-alpha (122 min), respectively. These results suggested that PVP is a useful polymeric modifier for increasing the anti-tumor activity of PVP.

  2. Water vapor absorption into amorphous sucrose-poly(vinyl pyrrolidone) and trehalose-poly(vinyl pyrrolidone) mixtures.

    PubMed

    Zhang, J; Zografi, G

    2001-09-01

    Previous studies from this laboratory suggested that a solution model (Flory-Huggins equation) modified by a free volume model (Vrentas equation) could satisfactorily describe water absorption into an amorphous solid composed of a sugar or a polymer. This paper has extended the studies of single solutes to binary mixtures of trehalose-and sucrose-poly(vinyl pyrrolidone) (trehalose-PVP and sucrose-PVP, respectively) either co-lyophilized or individually lyophilized and then physically mixed. Water vapor absorption isotherms of the binary mixtures were determined at 30 degrees C. Co-lyophilized PVP-sugar mixtures take up essentially the same amount of water as predicted by the weight average of individual isotherms, whereas sugar crystallization is significant retarded in the molecular dispersions. The sugar-PVP interaction, as reflected in the Flory-Huggins chi interaction parameter, was estimated by fitting the high relative pressure (p/p(0)) region of the isotherm, at which the system is in a liquid state, with a three-component Flory-Huggins-type model. The estimated sugar-water PVP-water, and sugar-PVP interaction parameters suggest that the solute-water interactions are not significantly affected by the sugar-PVP interaction; that is, the solute-water interaction parameters in a binary solute system are similar to those in the corresponding single solute systems. Based on these interaction parameters, the sucrose-PVP interaction appears to be stronger than that of trehalose-PVP. Manipulation of the interaction parameters suggest that the water vapor absorption isotherm is not a sensitive indicator of possible sugar-PVP interactions. Density, glass transition temperature, T(g), and the heat capacity change, DeltaC(p), at T(g) were determined to estimate the excess water absorption energy due to the plasticizing effect of water using the structural relaxation model, as described by Vrentas. Results suggest that PVP is a better antiplasticizer for sucrose than for

  3. Molecular dynamics simulation of amorphous indomethacin-poly(vinylpyrrolidone) glasses: solubility and hydrogen bonding interactions.

    PubMed

    Xiang, Tian-Xiang; Anderson, Bradley D

    2013-03-01

    Amorphous drug dispersions are frequently employed to enhance solubility and dissolution of poorly water-soluble drugs and thereby increase their oral bioavailability. Because these systems are metastable, phase separation of the amorphous components and subsequent drug crystallization may occur during storage. Computational methods to determine the likelihood of these events would be very valuable, if their reliability could be validated. This study investigates amorphous systems of indomethacin (IMC) in poly(vinylpyrrolidone) (PVP) and their molecular interactions by means of molecular dynamics (MD) simulations. IMC and PVP molecules were constructed using X-ray diffraction data, and force-field parameters were assigned by analogy with similar groups in Amber-ff03. Five assemblies varying in PVP and IMC composition were equilibrated in their molten states then cooled at a rate of 0.03 K/ps to generate amorphous glasses. Prolonged aging dynamic runs (100 ns) at 298 K and 1 bar were then carried out, from which solubility parameters, the Flory-Huggins interaction parameter, and associated hydrogen bonding properties were obtained. Calculated glass transition temperature (T(g)) values were higher than experimental results because of the faster cooling rates in MD simulations. Molecular mobility as characterized by atomic fluctuations was substantially reduced below the T(g) with IMC-PVP systems exhibiting lower mobilities than that found in amorphous IMC, consistent with the antiplasticizing effect of PVP. The number of IMC-IMC hydrogen bonds (HBs) formed per IMC molecule was substantially lower in IMC-PVP mixtures, particularly the fractions of IMC molecules involved in two or three HBs with other IMC molecules that may be potential precursors for crystal growth. The loss of HBs between IMC molecules in the presence of PVP was largely compensated for by the formation of IMC-PVP HBs. The difference (6.5 MPa(1/2)) between the solubility parameters in amorphous IMC

  4. Photoselective vaporisation of the prostate using 80-W and 120-W laser versus transurethral resection of the prostate for benign prostatic hyperplasia: a systematic review with meta-analysis from 2002 to 2012.

    PubMed

    Thangasamy, Isaac A; Chalasani, Venu; Bachmann, Alexander; Woo, Henry H

    2012-08-01

    Photoselective vaporisation (PVP) of the prostate is being used increasingly to treat symptomatic benign prostatic hyperplasia, due to the associated lower morbidity. Holmium laser enucleation of the prostate was considered to be the treatment with the highest evidence; however, evidence for PVP has dramatically increased recently. To conduct a systematic review and meta-analysis of level 1 evidence studies to determine the effectiveness of PVP versus transurethral resection of the prostate (TURP) for surgical treatment of benign prostatic hyperplasia. Outcomes reviewed included perioperative data, complications, and functional outcomes. Biomedical databases from 2002 to 2012 and American Urological Association and European Association of Urology conference proceedings from 2007 to 2011 were searched. Trials were included if they were randomised controlled trials, had PVP as the intervention, and TURP as control. Meta-analysis was performed using a random effects model. Nine trials were identified with 448 patients undergoing PVP (80 W in five trials and 120 W in four trials) and 441 undergoing TURP. Catheterisation time and length of stay were shorter in the PVP group by 1.91 d (95% confidence interval [CI], 1.47-2.35; p<0.00001) and 2.13 d (95% CI, 1.78-2.48; p<0.00001), respectively. Operation time was shorter in the TURP group by 19.64 min (95% CI, 9.05-30.23; p=0.0003). Blood transfusion was significantly less likely in the PVP group (risk ratio: 0.16; 95% CI, 0.05-0.53; p=0.003). There were no significant differences between PVP and TURP when comparing other complications. Regarding functional outcomes, six studies found no difference between PVP and TURP, two favoured TURP, and one favoured PVP. Perioperative outcomes of catheterisation time and length of hospital stay were shorter with PVP, whereas operative time was longer with PVP. Postoperative complications of blood transfusion and clot retention were significantly less likely with PVP; no difference

  5. General in vitro method to analyze the interactions of synthetic polymers with human antibody repertoires.

    PubMed

    Soshee, Anandakumar; Zürcher, Stefan; Spencer, Nicholas D; Halperin, Avraham; Nizak, Clément

    2014-01-13

    Recent reports on the hitherto underestimated antigenicity of poly(ethylene glycol) (PEG), which is widely used for pharmaceutical applications, highlight the need for efficient testing of polymer antigenicity and for a better understanding of its molecular origins. With this goal in mind, we have used the phage-display technique to screen large, recombinant antibody repertoires of human origin in vitro for antibodies that bind poly(vinylpyrrolidone) (PVP). PVP is a neutral synthetic polymer of industrial and clinical interest that is also a well-known model antigen in animal studies, thus allowing the comparison of in vitro and in vivo responses. We have identified 44 distinct antibodies that bind specifically to PVP. Competitive binding assays show that the PVP-antibody binding constant is proportional to the polymerization degree of PVP and that specific binding is detected down to the vinylpyrrolidone (VP) monomer level. Statistical analysis of anti-PVP antibody sequences identifies an amino-acid motif that is shared by many phage-display-selected anti-PVP antibodies that are similar to a previously described natural anti-PVP antibody. This suggests a role for this motif in specific antibody/PVP interactions. Interestingly, sequence analysis also suggests that only a single antibody chain containing this shared motif is responsible for antibody binding to PVP, as confirmed upon systematic deletion of either antibody chain for 90% of selected anti-PVP antibodies. Overall, a large number of antibodies in the human repertoires we have screened bind specifically to PVP through a small number of shared amino acid motifs, and preliminary comparison points to significant correlations between the sequences of phage-display-selected anti-PVP antibodies and their natural counterparts isolated from immunized mice in previous studies. This study pioneers the use of antibody phage-display to explore the antigenicity of biotechnologically relevant polymers. It also paves the

  6. 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.

  7. Morphological changes from silica tubules to hollow spheres controlled by the intermolecular interactions within block copolymer micelle templates.

    PubMed

    Lee, Hyemin; Char, Kookheon

    2009-04-01

    The morphological changes from tubules to large hollow spheres to (micelle-sized) small hollow-spherical silica were realized by polystyrene-block-poly(vinylpyridine) (PS-b-PVP) block copolymer micelle templates by controlling the intermolecular interactions with the corona chains. PS-b-PVP with weak intermolecular interactions among PVP corona chains yields the coexistence of tubules, large hollow spheres, and small hollow spheres. The coexistence of the three phases arises from the direct aggregation of block copolymer micelles during hydrolytic condensation of a silica precursor (tetraethylorthosilicate), as evidenced by transmission electron microscopy. When the degree of intermolecular interactions within the PVP corona blocks is increased by a change in either the degree of quaternization of the PVP blocks or the dielectric constant of the medium, small hollow spherical silica, with size equivalent to the block copolymer micelles, were solely obtained. We believe that this morphological change is due to the fact that the dipole-dipole interactions among quaternized PVP blocks physically cross-link the PVP coronas in micelles resisting the curvature change during the silica condensation.

  8. Neuropsychological outcome following pallidotomy and thalamotomy for Parkinson's disease.

    PubMed

    Fukuda, M; Kameyama, S; Yoshino, M; Tanaka, R; Narabayashi, H

    2000-01-01

    Cognitive and emotional outcomes were assessed after unilateral posteroventral pallidotomy (PVP) and ventral intermediate nucleus thalamotomy (Vim-Th) in patients suffering from idiopathic Parkinson's disease (PD). PVP was performed on 12 PD patients (8 men and 4 women, mean age 56.4 years, 6 left lesions and 6 right lesions) and Vim-Th was performed on 13 PD patients (5 men and 8 women, mean age 63.2 years, 6 left lesions and 7 right lesions). In both the PVP group and the Vim-Th group, the Hoehn and Yahr staging scores (p < 0.01) and the Unified Parkinson's Disease Rating Scale activities of daily living and motor scores (p < 0.001) improved significantly. No significant changes in cognitive function were observed 4 weeks after unilateral PVP or Vim-Th. PVP produced a significant decline in Hasegawa's Dementia Scale-Revised scores in immediate postoperative assessments (p < 0.05), which resolved 4 weeks after surgery. While the Minnesota Multiphasic Personality Inventory depression and social introversion scores improved significantly in the Vim-Th group (p < 0.01 and p < 0.05, respectively), the hypochondriasis and hypomania scores improved significantly in the PVP group (p < 0.01 and p < 0.05, respectively). We conclude that PVP and Vim-Th influence postoperative emotional status rather than postoperative cognitive status. Copyright 2000 S. Karger AG, Basel

  9. Effect of water-soluble polymers, polyethylene glycol and poly(vinylpyrrolidone), on the gelation of aqueous micellar solutions of Pluronic copolymer F127.

    PubMed

    Ricardo, Nágila M P S; Ricardo, Nadja M P S; Costa, Flávia de M L L; Bezerra, Francisco W A; Chaibundit, Chiraphon; Hermida-Merino, Daniel; Greenland, Barnaby W; Burattini, Stefano; Hamley, Ian W; Keith Nixon, S; Yeates, Stephen G

    2012-02-15

    The micellization of F127 (E(98)P(67)E(98)) in dilute aqueous solutions of polyethylene glycol (PEG6000 and PEG35000) and poly(vinylpyrrolidone) (PVP K30 and PVP K90) is studied. The average hydrodynamic radius (r(h,app)) obtained from the dynamic light scattering technique increased with increase in PEG concentration but decreased on addition of PVP, results which are consistent with interaction of the micelles with PEG and the formation of micelles clusters, but no such interaction occurs with PVP. Tube inversion was used to determine the onset of gelation. The critical concentration of F127 for gelation increased on addition of PEG and of PVP K30 but decreased on addition of PVP K90. Small-angle X-ray scattering (SAXS) was used to show that the 30 wt% F127 gel structure (fcc) was independent of polymer type and concentration, as was the d-spacing and so the micelle hard-sphere radius. The maximum elastic modulus (G(max)(')) of 30 wt% F127 decreased from its value for water alone as PEG was added, but was little changed by adding PVP. These results are consistent with the packed-micelles in the 30 wt% F127 gel being effectively isolated from the polymer solution on the microscale while, especially for the PEG, being mixed on the macroscale.

  10. 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.

  11. Au-induced polyvinylpyrrolidone aggregates with bound water for the highly shape-selective synthesis of silica nanostructures.

    PubMed

    Zhang, Jianhui; Liu, Huaiyong; Wang, Zhenlin; Ming, Naiben

    2008-01-01

    Novel Au-induced polyvinylpyrrolidone (PVP) aggregates with bound water (PVP-water) were created for the highly shape-selective synthesis of distinctive silica nanostructures, such as core-shell spheres, rods, snakes, tubes, capsules, thornlike, and dendritic morphologies. A water/PVP/n-pentanol system was first designed to bind water to PVP, and then Au nanoparticles were used to induce the PVP-water species to aggregate into distinctive soft structures by exploiting the interplay between PVP and gold. This was confirmed by the IR absorption spectra. The bound water in the soft structures was consumed during the hydrolysis of tetraethylorthosilicate and the target silica nanostructures were obtained. The soft structures, and therefore, the silica morphologies, can be readily tuned by adjusting the experimental parameters. The tunable Au-induced PVP-water soft structures reported herein open up new dimensions for the synthesis of distinctive nanomaterials (other than silica) that have new physicochemical properties and applications. These soft structures were also successfully extended to synthesize ZnO and SnO(2) particles with remarkable shapes, such as spheres, leaves, T-shaped structures, and dendritic morphologies.

  12. Characterization of poly(4-vinylpyridine 1-oxide) by free-solution capillary electrophoresis and micellar electrokinetic chromatography.

    PubMed

    Beneito-Cambra, Miriam; Herrero-Martínez, José M; Ramis-Ramos, Guillermo

    2008-08-01

    The migration characteristics of poly(4-vinylpyridine 1-oxide) (PVP-NO) in phosphate buffers of acidic pH (20 mM H3PO4 or NaH2PO4) have been studied using both free-solution capillary electrophoresis (FSCE) and MEKC. To inhibit adsorption, 250 mM o-phosphoethanolamine (2-aminoethyl dihydrogen phosphate) was used. In FSCE, PVP-NO showed a narrow peak and a broader band, both having anionic behavior. These peak and band were attributed to the free and aggregated or micellized PVP-NO forms, respectively. According to surface tension measurements, the CMC of SDS in the BGE was 1.8 and 0.48 mM in the absence and in the presence of 1000 microg/mL PVP-NO, respectively, and the association of the polymer with SDS was completed at 9.7 mM SDS. Using MEKC, a narrow peak and a broader band also appeared at SDS concentrations of ca. 1 mM, and their intensity increased with the SDS concentration. These peak and band were attributed to the formation of mixed micelles constituted by both free PVP-NO/SDS and aggregated PVP-NO/SDS, respectively. The determination of PVP-NO by FSCE in commercial additives for laundry was demonstrated.

  13. The solution behavior of poly(vinylpyrrolidone): its clouding in salt solution, solvation by water and isopropanol, and interaction with sodium dodecyl sulfate.

    PubMed

    Dan, Abhijit; Ghosh, Soumen; Moulik, Satya P

    2008-03-27

    This article deals with the solution properties of poly(vinylpyrrolidone) (PVP) in salt and surfactant environment. The cloud point (CP) of PVP has been found to be induced by the salts NaCl, KCl, KBr, Na2SO4, MgSO4, and Na3PO4. On the basis of CP values for a salt at different [PVP], the energetics of the clouding process have been estimated. The effect of the surfactant, sodium dodecyl sulfate (SDS), on the salt-induced CP has also been studied, and reduction in CP at low [SDS] and increase in CP at high [SDS] have been observed. The water vapor adsorption of PVP has been determined by isopiestic method. The results display a BET Type III isotherm whose analysis has helped to obtain the monolayer capacity of PVP and formation of multilayer on it. The solvation of PVP in a solution of water and a water-isopropanol mixture has been determined by conductometry from which contribution of the individual components were estimated. The interaction of PVP with SDS in solution led to formation of a complex entity, which has been studied also by conductometry adopting a binding-equilibrium scheme. SDS has been found to undergo two types of binding as monomers in the pre- critical aggregation concentration (CAC) range and as small clusters in the post CAC region. The stoichiometries of binding and binding constant were evaluated.

  14. 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.

  15. 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.

  16. The physical and chemical properties of the polyvinylalcohol/polyvinylpyrrolidone/hydroxyapatite composite hydrogel.

    PubMed

    Ma, Yahui; Bai, Tongchun; Wang, Fei

    2016-02-01

    A hydrogel of polyvinylalcohol (PVA)/polyvinylpyrrolidone (PVP)/hydroxyapatite (HA) was prepared by a repeated freezing and thawing technique. The effect of HA on the hydrogel was evaluated by comparing the physical and chemical properties of PVA/PVP/HA and PVA/PVP hydrogels. By using theoretical models, the information about the swelling kinetics and the dehydration kinetics have been obtained. From the analysis of structure, mechanical properties, and molecular interaction, the application of PVA/PVP/HA hydrogel as a biomaterial has been evaluated. Relative to PVA/PVP, the PVA/PVP/HA hydrogel is of denser network structure, lower water content, larger storage modulus, and higher dehydration activation energy. These results reveal that, as HA fills in the hydrogel, the molecular interaction is enhanced, the free space of network is compressed, and the diffusion activation energy of water is increased. In spite of its water content being decreased, it is still in the range of meeting the requirement of bio-application. When the hydrogel is subjected to external forces, the matrix will transfer the load to the HA powder, thus enhance the strength of the hydrogel. For application in bio-materials, HA will still have osteoinductivity because its crystalline structure is not interrupted in PVA/PVP/HA hydrogel environment.

  17. Preparation and in vitro evaluation of povidone-sodium cholate-phospholipid mixed micelles for the solubilization of poorly soluble drugs.

    PubMed

    Zhu, Yuan; Yu, Jiangnan; Tong, Shanshan; Wang, Li; Peng, Min; Cao, Xia; Xu, Ximing

    2010-06-01

    Mixed micelles made of polyvinylpyrrolidone (PVP), sodium cholate, and phospholipids were prepared to improve the solubility of poorly water-soluble drugs. Sylibin, a drug used in treating liver diseases, was incorporated into the mixed micelles. The formulation of sylibin containing PVP-sodium cholate-phospholipid mixed micelles with an optimized composition (PVP/sodium cholate/phospholipid/silybin = 3:3:4:1 approximately 2 by weight) was obtained based on the study of pseudoternary phase diagrams. The critical micelle concentration was used to evaluate the micellar stability towards dilution. The results showed that addition of PVP to sodium-cholate-phospholipid mixed micelles increased stability. The solubility of sylibin in PVP-sodium cholate-phospholipid mixed micelles was higher than that in pure water or in sodium cholate-phospholipid mixed micelles. In a stability study, we found that PVP-sodium cholate-phospholipid mixed micelles showed good stability. After 3 months storage at 40 degrees C, just 2.6% sylibin was lost with only minor changes of the particle size when compared to a reference formulation containing sodium cholate and phospholipid mixed micelles. In addition, the developed formulation significantly improved in vitro drug release. The time required to release 50% sylibin (t50%) from sodium cholate and phospholipid mixed micelles was 326 h, while the t50% from PVP-sodium cholate-phospholipid mixed micelles was only 51.1 h. Our results suggest that these mixed micelles might have significant potential application to the biomedical field.

  18. A comparison between povidone-ethylcellulose and povidone-eudragit transdermal dexamethasone matrix patches based on in vitro skin permeation.

    PubMed

    Mukherjee, Biswajit; Mahapatra, Sushmita; Gupta, Ritu; Patra, Balaram; Tiwari, Amit; Arora, Priyanka

    2005-04-01

    The present study was designed to develop a suitable matrix type transdermal drug delivery system (TDDS) of dexamethasone using blends of two different polymeric combinations, povidone (PVP) and ethylcellulose (EC) and Eudragit with PVP. Physical studies including moisture content, moisture uptake, flatness to study the stability of the formulations and in vitro dissolution of the experimental formulations were performed to determine the amount of dexamethasone present in the patches were performed and scanning electron microscopy (SEM) photographs of the prepared TDDS were taken to see the drug distribution pattern. Drug-excipient interaction studies were carried out using Fourier transform infrared (FTIR) spectroscopic technique. In vitro skin permeation study was conducted in a modified Franz's diffusion cell. All the formulations were found to be suitable for formulating in terms of physicochemical characteristics and there was no significant interaction noticed between the drug and polymers used. In vitro dissolution studies showed that the drug distribution in the matrix was homogeneous and the SEM photographs further demonstrated this. The formulations of PVP:EC provided slower and more sustained release of drug than the PVP:Eudragit formulations during skin permeation studies and the formulation PVP:EC (1:5) was found to provide the slowest release of drug. Based on the above observations, it can be reasonably concluded that PVP-EC polymers are better suited than PVP-Eudragit polymers for the development of TDDS of dexamethasone.

  19. In vitro short-time killing activity of povidone-iodine (Isodine Gargle) in the presence of oral organic matter.

    PubMed

    Yoneyama, Akiko; Shimizu, Masaki; Tabata, Makiko; Yashiro, Junko; Takata, Toshihiko; Hikida, Muneo

    2006-01-01

    In order to estimate the clinical efficacy of a povidone-iodine oral antiseptic (PVP-I) on oral bacterial infectious diseases, we studied the effect of oral organic matter on the in vitro killing activity of PVP-I. In addition, we compared the in vitro short-time killing activity of PVP-I with those of other oral antiseptics using mouth-washing and gargling samples collected from healthy volunteers. When any of the mouth-washing and gargling samples was used, the standard (0.23-0.47%) or lower concentrations of PVP-I killed methicillin-resistant Staphylococcus aureus (MRSA) and Pseudomonas aeruginosa, including multidrug-resistant strains, within 15-60 s in the presence of oral organic matter. 0.02% benzethonium chloride (BEC) and 0.002% chlorhexidine gluconate (CHG) did not show effects against MRSA and P. aeruginosa (including multidrug-resistant strains) in mouth-washing and gargling samples even after 60 s. The above-mentioned results show that the in vitro killing activity of the standard concentration of PVP-I was hardly affected by the oral organic matter and that a mouth-washing or gargling solution containing PVP-I has a stronger bactericidal activity than BEC and CHG. Although mouth-washing and gargling samples were obtained from healthy individuals in this study, PVP-I may be used for protection against infections in patients with various diseases, if proper concentrations and usage are encouraged.

  20. 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.

  1. Photoalignment of a Bisazodioxodibenzothiophene in a Polyvinylpyrrolidone Matrix

    NASA Astrophysics Data System (ADS)

    Chaplanova, J. D.; Larykava, S. N.; Agabekov, V. E.; Mikulich, V. S.; Gracheva, E. A.

    2016-09-01

    Photoalignment of thin films of dipotassium 3,7-bis[1-(4-hydroxy-3-carboxylate)phenylazo]-5,5'-dioxodibenzothiophene (AtA-2) that were prepared by spin-coating of dye solutions in H2O and DMF and aqueous solutions of polyvinylpyrrolidone (PVP) was studied. The UV absorption band of the dye cis-isomer, the position and intensity of which depended on the PVP concentration in the stock solutions, was recorded upon irradiation of films of AtA-2 in a PVP matrix [AtA-2(PVP)] with unfi ltered light from a DRT-1000 lamp in a vacuum or an Ar atmosphere. PVP facilitated trans-cis isomerization of AtA-2 and increased the stability of the cis-isomer with respect to thermal relaxation into the initial trans-isomer. The dichroic ratio (DR) of AtA-2(PVP) films irradiated with linearly polarized light (blue LED with λ = 450 nm, I = 15 mW/cm2) increased by 1.5 times as the PVP concentration in the stock solutions increased from 1.0 to 10.0 mass%. The morphology and roughness of the films depended on the nature of the solvents used to prepare them.

  2. 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. Copyright (c) 2010 Elsevier B.V. All rights reserved.

  3. Percutaneous Vertebroplasty Relieves Pain in Cervical Spine Metastases

    PubMed Central

    Bao, Li; Jia, Pu; Li, Jinjun; Chen, Hao; Dong, Yipeng; Feng, Fei; Yang, He; Chen, Mengmeng

    2017-01-01

    Percutaneous vertebroplasty (PVP) has been shown to release spinal pain and stabilize the vertebral body. PVP is suggested as an alternative treatment in spinal metastasis. Although cervical metastases is less prevalent than thoracic and lumbar spine, PVP procedure in cervical vertebrae remains technical challenging. We retrospectively analyzed the data from patients (n = 9) who underwent PVP using anterolateral approach to treat severe neck pain and restricted cervical mobility from metastatic disease. Patients were rated using modified Tokuhashi score and Tomita score before the procedure. Visual analog scale (VAS), neck disability index (NDI), analgesic use, and imaging (X-ray or CT) were evaluated before PVP and 3 days, 3 months, and 6 months after PVP. All patients were in late stage of cancer evaluated using modified Tokuhashi and Tomita score. The cement leakage rate was 63.6% (14 of the 22 vertebrae) with no severe complications. VAS, NDI, and analgesic use were significantly decreased 3 days after the procedure and remained at low level until 6 months of follow-up. Our result suggested PVP effectively released the pain from patients with cervical metastasis. The results warrant further clinical investigation. PMID:28239257

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

    NASA Astrophysics Data System (ADS)

    Lim, Jin Ik; Kang, Min Ji; Lee, Woo-Kul

    2014-11-01

    For postsurgical anti-adhesion barrier applications, lotus-leaf-like structured chitosan-PVP films were prepared using a solution casting method with dodecyltrichloro-immobilized SiO2 nanoparticles. We evaluated whether the lotus-leaf-like structured chitosan-PVP films (L-chitosan-PVP) could be applied as postsurgical anti-adhesion barriers. A recovery test using a tensile strength testing machine and measurement of crystallinity using X-ray diffraction indicated that films with 75% PVP were the optimal composition of the chitosan-PVP films. Also, dodecyltrichloro-immobilized SiO2 nanoparticles were synthesized and sprayed on the film after pretreatment with the instant bio-glue. Analysis of cell adhesion, proliferation, and anti-thrombus efficiency were performed via a WST assay, field emission scanning electron microscopy, and hemacytometry. The contact angle with the lotus-leaf-like surface was of approximately 150°. Furthermore, the L-chitosan-PVP film yielded a lower cell and platelet adhesion rate (around less than 4%) than that yielded by the untreated film. These results indicate that the lotus-leaf-like structure has a unique property and that this novel L-chitosan-PVP film can be applied as a blood/tissue-compatible, biodegradable material for implantable medical devices that need an anti-adhesion barrier.

  5. Systemic iodine absorption after preoperative antisepsis using povidone-iodine in cataract surgery-- an open controlled study.

    PubMed

    Below, H; Behrens-Baumann, W; Bernhardt, C; Völzke, H; Kramer, A; Rudolph, P

    2006-01-01

    After preoperative conjunctival and periorbital antisepsis with povidone-iodine (PVP-I), the systemic absorption of iodine after cataract surgery was measured to evaluate the risk of thyroid side effects. Five different combinations of PVP-I alone or in combination with PVP-I-free antiseptics were applied to the conjunctiva and periorbital skin. An iodine-free product served as control. Iodide and creatinine in urine were analyzed before intervention and 24 and 48 h postoperatively. Depending on the concentration and application site, 0.3-4.5% of the total applied iodine or 3.6-45.4% of the free iodine were absorbed. The range of urine iodine excretion was between 11.7 and 71.0 mug iodine/g creatinine, depending on the PVP-I concentration and the site of application. The increase in iodine excretion was significant at 24 h postoperatively in trials receiving PVP-I both periorbitally and conjunctivally, depending of the concentration used. Because the iodine absorption is only slight and of doubtful clinical relevance, presurgical conjunctival antisepsis can be achieved with 1.25% PVP-I; so far clinically manifest anamnestic thyroid disorders are excluded. Presently, periorbital skin antisepsis with PVP-I cannot be recommended until data on thyroid metabolism in the population have been collected and evaluated, especially in a region currently or previously deficient in iodine.

  6. Ability of polyvinylpyrrolidone and polyacrylic acid to inhibit the crystallization of amorphous acetaminophen.

    PubMed

    Miyazaki, Tamaki; Yoshioka, Sumie; Aso, Yukio; Kojima, Shigeo

    2004-11-01

    The inhibition of crystallization of amorphous acetaminophen (ACTA) by polyvinylpyrrolidone (PVP) and polyacrylic acid (PAA) was studied using amorphous solid dispersions prepared by melt quenching. Co-melting with PVP and PAA decreased the average molecular mobility, as indicated by increases in glass transition temperature and enthalpy relaxation time. The ACTA/PAA dispersion exhibited much slower crystallization than the ACTA/PVP dispersion with a similar glass transition temperature value, indicating that interaction between ACTA and polymers also contributed to the stabilizing effect of these polymers. The carboxyl group of PAA may interact with the hydroxyl group of ACTA more intensely than the carbonyl group of PVP does, resulting in the stronger stabilizing effect of PAA. Dielectric relaxation spectroscopy showed that the number of water molecules tightly binding to PVP per monomer unit was larger than that to PAA. Furthermore, a small amount of absorbed water decreased the stabilizing effect of PVP, but not that of PAA. These findings suggest that the stronger stabilizing effect of PAA is due to the stronger interaction with ACTA. The ability of PAA to decrease the molecular mobility of solid dispersion was also larger than that of PVP, as indicated by the longer enthalpy relaxation time.

  7. Instantaneous Pulsed-Light Cross-Linking of a Polymer Gate Dielectric for Flexible Organic Thin-Film Transistors.

    PubMed

    Kim, Soo Jin; Jang, Mi; Yang, Hee Yeon; Cho, Jinhan; Lim, Ho Sun; Yang, Hoichang; Lim, Jung Ah

    2017-04-05

    We report the instantaneous pulsed-light cross-linking of polymer gate dielectrics on a flexible substrate by using intensely pulsed white light (IPWL) irradiation. Irradiation with IPWL for only 1.8 s of a poly(4-vinylphenol) (PVP) thin film with the cross-linking agent poly(melamine-co-formaldehyde) (PMF) deposited on a plastic substrate was found to yield fully cross-linked PVP films. It was confirmed that the IPWL-cross-linked PVP films have smooth pinhole-free surfaces and exhibit a low leakage current density, organic solvent resistance, and good compatibility with organic semiconductor, and that they can be used as replacements for typical PVP dielectrics that are cross-linked with time and energy intensive thermal heating processes. The synchronization of the IPWL irradiation with substrate transfer was found to enable the preparation of cross-linked PVP films on large area substrates with a highly uniform capacitance. Flexible OTFT based on IPWL-cross-linked PVP dielectrics were found to exhibit good electrical performance that is comparable to that of devices with thermally cross-linked PVP dielectric, as well as excellent deformation stability even at a bending radius of 3 mm.

  8. The effect of hydrophilic chain length and iRGD on drug delivery from poly(ε-caprolactone)-poly(N-vinylpyrrolidone) nanoparticles.

    PubMed

    Zhu, Zhenshu; Xie, Chen; Liu, Qin; Zhen, Xu; Zheng, Xianchuang; Wu, Wei; Li, Rutian; Ding, Yin; Jiang, Xiqun; Liu, Baorui

    2011-12-01

    Poly(ε-caprolactone)-b-Poly(N-vinylpyrrolidone) (PCL-b-PVP) copolymers with different PVP block length were synthesized by xanthate-mediated reverse addition fragment transfer polymerization (RAFT) and the xanthate chain transfer agent on chain end was readily translated to hydroxy or aldehyde for conjugating various functional moieties, such as fluorescent dye, biotin hydrazine and tumor homing peptide iRGD. Thus, PCL-PVP nanoparticles were prepared by these functionalized PCL-b-PVP copolymers. Furthermore, paclitaxel-loaded PCL-PVP nanoparticles with satisfactory drug loading content (15%) and encapsulation efficiency (>90%) were obtained and used in vitro and in vivo antitumor examination. It was demonstrated that the length of PVP block had a significant influence on cytotoxicity, anti-BSA adsorption, circulation time, stealth behavior, biodistribution and antitumor activity for the nanoparticles. iRGD on PCL-PVP nanoparticle surface facilitated the nanoparticles to accumulate in tumor site and enhanced their penetration in tumor tissues, both of which improved the efficacy of paclitaxel-loaded nanoparticles in impeding tumor growth and prolonging the life time of H22 tumor-bearing mice.

  9. Balloon Kyphoplasty Compared to Vertebroplasty and Non-Surgical Management in Patients Hospitalised with Acute Osteoporotic Vertebral Compression Fracture – A UK Cost-Effectiveness Analysis

    PubMed Central

    Alvares, L; Cooper, C; Marsh, D; Ström, O

    2013-01-01

    Objective To estimate the cost-effectiveness of Balloon Kyphoplasty (BKP) for the treatment of patients hospitalised with acute Osteoporotic Vertebral Compression Fracture (OVCF) compared to Percutaneous Vertebroplasty (PVP) and Non-Surgical Management (NSM) in the UK. Methods A Markov simulation model was developed to evaluate treatment with BKP, NSM and PVP in patients with symptomatic OVCF. Data on health related quality of life (HRQoL) with acute OVCF were derived from the FREE and VERTOS II Randomised Clinical Trials (RCTs) and normalized to the NSM arm in the FREE trial. Estimated differences in mortality among the treatments and costs for NSM were obtained from the literature whereas procedure costs for BKP and PVP were obtained from three NHS hospitals. It was assumed that BKP and PVP reduced hospital length of stay by six days compared to NSM. Results The incremental cost-effectiveness ratio (ICER) was estimated at GBP 2,706 per QALY and GBP 15,982 per QALY compared to NSM and PVP respectively. Sensitivity analysis showed that the cost-effectiveness of BKP vs. NSM was robust when mortality and HRQoL benefits with BKP were varied. The cost-effectiveness of BKP compared to PVP was particularly sensitive to changes in the mortality benefit. Conclusion BKP may be a cost-effective strategy for the treatment of patients hospitalised with acute OVCF in the UK compared to NSM and PVP. Additional RCT data on the benefits of BKP and PVP compared to simulated sham-surgery and further data on the mortality benefits with BKP compared to NSM and PVP would reduce uncertainty. PMID:22890362

  10. 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

  11. Silicon-dioxide-polyvinylpyrrolidone as a wound dressing for skin defects in a murine model.

    PubMed

    Öri, Ferenc; Dietrich, Richard; Ganz, Cornelia; Dau, Michael; Wolter, Daniel; Kasten, Annika; Gerber, Thomas; Frerich, Bernhard

    2017-01-01

    There is a high demand for temporary wound dressings that improve wound healing and regeneration. Silicon (as SiO2) has been shown to support the growth and collagen formation in biological systems. A nanocomposite was made from PVP (polyvinylpyrrolidon), nano-sized silica aggregates and water and served for fabrication of a wet dressing material (SiO2-PVP gel, by cross-linking the gel) and a freeze-dried dressing material (SiO2-PVP fleece). Materials were characterized by SAXS, DSC, EDX and viscosity measurements. A 10 mm circular defect was set on both sides of the back of SKH1-hr mice (n = 40) and both dressing materials were compared with untreated controls. After 3, 6, 9, 12 and 15 days, the defect regions were explanted and evaluated by histomorphometric measurements and CD31-immunohistochemistry. The microstructure of the compound was composed of fiber like structures. SiO2 nano-aggregates inside the composite remained stable and embedded in a rigid amorphous PVP fraction. In animal experiments, all groups showed a non-irritated defect closure after 9 days. EDX of SiO2-PVP gel and fleeces revealed SiO2-PVP diffusion into the wound. Wound contraction was significantly enhanced after treatment with SiO2-PVP gel followed by SiO2-PVP fleece compared to controls. Re-epithelialization was increased in SiO2-PVP treated wounds and the regenerated epidermis showed a well-differentiated layer structure compared to untreated controls. The results indicate that silica diffuses from the dressing into the wound. Both dressings affect the wound healing. The SiO2-based wound dressing may counteract scarring and might be suitable as a temporary wound dressing. Copyright © 2016 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.

  12. 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.

  13. Evaluation of the anti-infectious properties of polyester vascular prostheses functionalised with cyclodextrin.

    PubMed

    Jean-Baptiste, Elixène; Blanchemain, Nicolas; Neut, Christel; Chai, Feng; Maton, Mickael; Martel, Bernard; Hildebrand, Hartmut; Haulon, Stéphan

    2014-02-01

    Synthetic vascular graft infection (SVGI) remains associated with high morbidity-mortality rates. Newly developed polyester vascular prostheses (PVP) functionalised with cyclodextrin (PVP-CD) allowed sustained-drug-eluting of several antibiotics. This study aimed to evaluate the efficacy of PVP-CD loaded with antibiotics against bacteria that are commonly responsible for SVGI in current practice. Samples of PVP-CD loaded with antibiotics and uncoated-PVP were tested in-vitro for their ability to limit bacterial adhesion and prevent bacterial proliferation over time. Their anti-infectious properties were further evaluated in-vivo in a mouse model of SVGI. Both Gram-positive (Staphylococcus aureus, Staphylococcus epidermidis, MRSA) and Gram-negative (Escherichia coli, En. cloacae and Pseudomonas aeruginosa) bacteria were tested. PVP-CD loaded with rifampin showed significant bacterial adhesion reduction and growth inhibition against Gram-positive bacteria. Similar results were obtained against Gram-negative bacteria with PVP-CD loaded with ciprofloxacin. In the mouse model, Gram-positive and Gram-negative bacterial proliferations were significantly prevented by PVP-CD loaded with rifampin or with ciprofloxacin respectively. A decrease in macroscopic infections correlated with the bacterial proliferation rates depicted on the samples (Spearman's rho = 0.61; P < 0.0001). We have demonstrated the efficacy of PVP-CD loaded with appropriate antibiotics both in-vitro and in-vivo against six of the most common bacteria involved in human SVGI. Copyright © 2013 The British Infection Association. Published by Elsevier Ltd. All rights reserved.

  14. Photoselective GreenLight™ laser vaporization versus transurethral resection of the prostate in Greece: a comparative cost analysis.

    PubMed

    Liatsikos, Evangelos; Kyriazis, Iason; Kallidonis, Panagiotis; Sakellaropoulos, George; Maniadakis, Nikos

    2012-02-01

    To compare photoselective vaporization of the prostate (PVP) using the 120W GreenLight™ laser with transurethral resection of the prostate (TURP) in terms of their cost to the Greek National Health Service (NHS) or to the Public Insurance Sickness Funds (PISF). A prospective cost evaluation with 1-year follow-up of 60 patients with infravesical obstruction of benign prostatic hyperplasia origin who underwent o either TURP (n=30) or PVP (n=30). The cost of equipment, consumables, anesthesia, drugs, inpatient hospitalization, and complication management within 1 year postoperatively were used to calculate the cost for the NHS. PISF reimbursements to hospitals and PISF opportunity cost from the lost days of work were used to calculate PISF perspective. From the NHS perspective, the average cost was €1722 ($2371) for PVP and €2132 ($2935) for TURP. From the PISF perspective, the average cost for hospital reimbursement was €1348 ($1856) in the case of PVP and €938 ($1291) in the case of TURP. Nevertheless, in the case of patients still working, total PISF reimbursement cost was €2038 ($2806) for PVP and €2666 ($3671) for TURP. PVP for 40 to 70 cc prostates is preferable from the perspective of the NHS. From the perspective of PISF, PVP is less costly only in the case of patients who are still working, because patients who undergo PVP stay much less out of work. Further investigation in larger populations as well as in different protocols of PVP hospitalization and return to work times is deemed necessary to reinforce the conclusions of this study.

  15. Photoselective Vaporization of the Prostate: Long-Term Outcomes and Safety During 10 Years of Follow-Up.

    PubMed

    Yamada, Yasushi; Furusawa, Jun; Sugimura, Yoshiki; Kuromatsu, Isao

    2016-12-01

    To evaluate the long-term outcomes and safety photoselective vaporization of the prostate (PVP). From April 2005 to December 2015, a total of 1154 patients with benign prostatic hyperplasia underwent PVP. The type of Green Light laser was an 80 W potassium-titanyl-phosphate laser and later a 120 W lithium triborate laser. Before and after surgery, the International Prostate Symptom Score (IPSS), maximum urinary flow rate (Qmax), post-voiding volume of residual urine (PVR), prostate-specific antigen (PSA) level, and prostate volume were assessed regularly. After surgery, events such as second PVP, transurethral incision, and permanent urethral catheterization were defined as retreatment. The mean and median periods of follow-up after PVP were 35.4 and 24.0 months, respectively. The maximum duration of follow-up was 125 months. Compared with before surgery, the IPSS, quality of life score, and PSA concentration improved significantly, even at 10 years after PVP; however, Qmax and PVR were not improved at 10 years. The retreatment-free survival rate was 93.9% at 5 years and 79.0% at 10 years. Prostate cancer was found in 27 cases after PVP, and all patients who were found to have prostate cancer remained alive. Prostate cancer-free survival after PVP was 96.7% at 5 years and 89.4% at 10 years. Our data suggest that the efficacy of PVP was maintained for 10 years; however, it may decrease after more than 10 years. PVP also did not promote the progression of or worsen the prognosis of prostate cancer.

  16. Novel associated hydrogels for nucleus pulposus replacement.

    PubMed

    Thomas, Jonathan; Lowman, Anthony; Marcolongo, Michele

    2003-12-15

    Hydrogels of poly(vinyl alcohol) (PVA) and poly(vinyl pyrrolidone) (PVP) blends may provide a material suitable for replacement of the nucleus pulposus of the intervertebral disc. This research examined the stability of these hydrogels under simulated physiological conditions. Polymer dissolution and stability were characterized over 120 days immersion, chemical surface analysis over 56 days immersion, and tensile mechanical behavior over 56 days immersion. Rubber elasticity theory was used by combining mechanical results with swelling data to calculate network characteristics such as the molecular weight between physical crosslinks and density of crosslinks. Properties were examined as a function of PVA/PVP composition as well as PVA molecular weight and PVP molecular weight. Results indicated that PVA/PVP blends prepared with moderate amounts of PVP (0.5-5%) resulted in a polymer network stabilized through interchain hydrogen bonding between hydroxyl groups on PVA chains and carbonyl groups on PVP chains. Most notably, a significant decrease in percentage of polymer mass loss was seen for blends prepared with 143K molecular weight PVA. Surface chemical analysis revealed that PVP unincorporated in the network structure suffered significant dissolution out of the polymer network and into solution. The molecular weight of PVA and PVP were shown to have a significant influence on the blends' network properties. Gels prepared with lower molecular weight PVA resulted in a more stable blend containing a higher density of crosslinks. However, blends prepared with a higher molecular weight PVA showed superior polymer network stability in dissolution studies. The blend that had the best combination of network stability under physiological conditions and a relatively tight, stable, and crosslinked network was prepared with 99% PVA (143K) and 1% PVP (40K). This material is proposed as an implant material for replacement of the degenerated nucleus pulposus.

  17. Povidone-iodine-induced cell death in cultured human epithelial HeLa cells and rat oral mucosal tissue.

    PubMed

    Sato, So; Miyake, Masao; Hazama, Akihiro; Omori, Koichi

    2014-07-01

    Although povidone-iodine (PVP-I) has been used as a gargle since 1956, its effectiveness and material safety have been remained controversial. The aim of this study was to investigate the toxicity of PVP-I to epithelial cells in a concentration range significantly lower than that used clinically. Study design was in vitro laboratory investigations and in vivo histological and immunologic analysis. We examined the effects of PVP-I at concentrations of 1 × 10(-2) to 1 × 10(3) μM and 1 × 10(-4) to 1 × 10 μM on HeLa cells as a model of epithelial cells and rat oral mucosa, respectively, after 1 or 2 days of exposure. Annexin V/FLUOS was used to distinguish live, apoptotic and necrotic cells. The terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) method was also used to observe whether apoptotic epithelial cells exist in rat oral mucosa after 1 day of exposure of PVP-I. HeLa cells developed concentration-dependent cytotoxicity, and epithelium of rat oral mucosa was thinned in a concentration-dependent manner. HeLa cell apoptosis increased after 1 × 10(0) μM of PVP-I exposure for 2 days. In the TUNEL method, many apoptotic epithelial cells were observed in the rat oral mucosa after 1 day of exposure to diluted 1 × 10(-2) μM of PVP-I, but minimal apoptotic epithelial cells were observed using 1 × 10(-3) μM of PVP-I. Our findings suggest that exposure to PVP-I, of which concentrations are even lower than those used clinically, causes toxicity in epithelial cells. This knowledge would help us better understand the risk of the use of PVP-I against mucosa.

  18. Electrospinning of artemisinin-loaded core-shell fibers for inhibiting drug re-crystallization.

    PubMed

    Shi, Yongli; Zhang, Jianhua; Xu, Shuxin; Dong, Anjie

    2013-01-01

    The main aim of this study was to inhibit the re-crystallization of a potent antimalarial drug, artemisinin (ART), by encapsulating it in core-shell fibers via a coaxially electrospun method. The ART-infiltrated cellulose acetate (CA) solution as the core material and poly(vinyl pyrrolidone) (PVP) solution as the shell material were used to prepared ART-loaded core-shell fibers ([ART/CA]/PVP). Transmission electron microscopy images confirmed the core-shell structures of the coaxially electrospun fibers. The scanning electron microscope (SEM), X-ray diffraction, and differential scanning calorimetry were performed to characterize the physical states of ART in the fibers. It was observed that ART crystals were formed in the ART-loaded CA/PVP composite fibers (ART/CA/PVP) during the electrospinning process and increased during storage duration. While ART crystals hardly were observed in the fresh core-shell [ART/CA]/PVP fibers with high ART entrapped amount (20 wt.%) and a little was detected after 6-month storage. Fourier transform infrared spectroscopy (FTIR) results illustrated the hydrogen bonding interaction between ART and CA in the core-shell [ART/CA]/PVP fibers mainly contributed to the amorphous state of ART. Importantly, combination of the hydrophilic PVP shell and the amorphous ART in CA core, the core-shell [ART/CA]/PVP fibers provided a continued and stable ART release manner. Ex vivo permeation studies suggested the amorphous ART in the medicated core-shell fibers could permeate through the stratum corneum smoothly. Hence, the core-shell [ART/CA]/PVP fiber matrix could provide a potential application in transdermal patches.

  19. Aerosolized polymerized type I collagen reduces airway inflammation and remodelling in a guinea pig model of allergic asthma.

    PubMed

    Moreno-Alvarez, Paola; Sánchez-Guerrero, Edgar; Martínez-Cordero, Erasmo; Hernández-Pando, Rogelio; Campos, María G; Cetina, Lucely; Bazán-Perkins, Blanca

    2010-04-01

    Collagen-polyvinylpyrrolidone (Collagen-PVP) has been demonstrated to elicit immunomodulatory properties in different chronic inflammatory diseases. Nevertheless, its effects on asthma are still unknown. We have evaluated whether collagen-PVP could modulate airway inflammation and remodelling in a guinea pig model of allergic asthma. Sensitized guinea pigs were challenged with the allergen (ovalbumin) six times (at 10-day intervals). From the third challenge on, animals were treated every 5 days with saline aerosols containing 0.16, 0.33, or 0.66 mg/ml of collagen-PVP (n = 5, respectively). Some guinea pigs, sensitized and challenged with saline as well as treated with 0 or 0.66 mg/ml collagen-PVP, were included in the study as control (n = 7) and sham groups (n = 5), respectively. From the first challenge on, ovalbumin induced a transient airway obstruction, measured by barometric plethysmography, which was not modified by collagen-PVP treatments. After the last allergen challenge, guinea pigs were anesthetized to obtain bronchoalveolar lavage (BAL) and the left lung caudal lobe. As expected, BAL cell count from allergen-challenged guinea pigs showed abundant neutrophils and eosinophils, as well as numerous tumor necrosis factor (TNF)-alpha-expressing granulocytes and macrophages in airway wall (determined by immunohistochemical assay). Neutrophilia and TNF-alpha-expressing leukocytes, from collagen-PVP treated animals, diminished from 0.16 mg/ml, and eosinophilia from 0.66 mg/ml of collagen-PVP doses. Histological changes induced by allergen challenges include thickening of connective tissue below airway epithelium and vascular wall widening of airway adjacent vessels; these changes were reduced by collagen-PVP treatment. Collagen-PVP seems to have anti-inflammatory and antifibrotic properties in this guinea pig asthma model.

  20. 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.

  1. 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.

  2. 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

  3. A Study of Pilot Selection for the Korean Air Force.

    DTIC Science & Technology

    1987-09-01

    positive, false positive, valid negative and F’alse negative have utility Uvp , Ufp I Uvn and Ufn respectively, then the expected utility can be...described generally: EU = Uvp x P(VP) + Ufp x P(FP) + Uvn x P(VN) + Ufn x P(FN) - UT where UT is the utility of testing method employed. Under different...number of applicants N, then the expected utility is going to be: EU = Uvp X P(VP) + Ufp x P(FP) + Urn x P(VN) + Ufn x P(FN) where P(VP) = BR X SR since rp

  4. Antineoplastic activity of povidone-iodine on different mesothelioma cell lines: results of in vitro study†

    PubMed Central

    Fiorelli, Alfonso; Pentimalli, Francesca; D'Urso, Vittorio; Di Marzo, Domenico; Forte, Iris Maria; Giordano, Antonio; Di Domenico, Marina; Accardo, Marina; Di Serio, Umberto; Santini, Mario

    2014-01-01

    OBJECTIVE Povidone-iodine (PVP-I) or Betadine, owing to its antineoplastic activity, is also used as an adjuvant during intra-abdominal or intrathoracic surgery. However, the protocol of PVP-I administration has not been optimized to achieve the best antitumoural efficacy. We aimed to determine the optimal concentration of PVP-I, the time of incubation and the mechanism of cell death by analysing the effect of different doses and time of administration of PVP-I on the cell viability of different mesothelioma cell lines. METHODS Four different cell lines (MET 5A/normal mesothelium; H2052/sarcomatoid mesothelioma; ISTMES2/epithelial mesothelioma; MSTO/biphasic mesothelioma) were incubated with increasing concentrations of diluted PVP-I (0.0001; 0.001; 0.01; 0.1; 1%) for 5, 10, 30, 60 min and 24 h, respectively. Cell viability was determined using cell direct cytotoxicity assay and cell death was determined through flow cytometry assay analysis. The superoxide dismutase activity was assessed functionally through a specific inhibitor to evaluate the mechanism of cell death. RESULTS The antiproliferative effect of PVP-I varied largely among different cell lines in a dose- and time-dependent manner. At 0.1% concentration for 10 min of incubation, the percentage of viable cells was 0.5 ± 0.1; 0.8 ± 0.5 and 0% (P < 0.01) for MET5A, ISTMES2 and MSTO, respectively. Conversely, the same concentration did not significantly affect the H2052 cell line which was completely suppressed at a 1% concentration of PVP-I. Double staining of Annexin V and DNA showed that PVP-I induced cell death in all four cell lines via necrosis depending on PVP-I concentration. However, H2052 was found to be more resistant than MSTO, ISTMES2 and MET 5A cells lines. The activity of superoxide dismutase was significantly inhibited in all cell lines. CONCLUSIONS Our results confirmed the anti-neoplastic activity of PVP-I especially on ISTMES2 and MSTO cell lines. With respect to chemotherapy pleural

  5. Poly(anhydride-ester) and poly(N-vinyl-2-pyrrolidone) blends: salicylic acid-releasing blends with hydrogel-like properties that reduce inflammation.

    PubMed

    Ouimet, Michelle A; Fogaça, Renata; Snyder, Sabrina S; Sathaye, Sameer; Catalani, Luiz H; Pochan, Darrin J; Uhrich, Kathryn E

    2015-03-01

    Polymers such as poly(N-vinyl-2-pyrrolidone) (PVP) have been used to prepare hydrogels for wound dressing applications but are not inherently bioactive. For enhanced healing, PVP was blended with salicylic acid-based poly(anhydride-esters) (SAPAE) and shown to exhibit hydrogel properties upon swelling. In vitro release studies demonstrated that the chemically incorporated drug (SA) was released from the polymer blends over 3-4 d in contrast to 3 h, and that blends of higher PVP content displayed greater swelling values and faster SA release. The polymer blends significantly the inflammatory cytokine, TNF-α, in vitro without negative effects.

  6. Poly(4-vinylphenol) gate insulator with cross-linking using a rapid low-power microwave induction heating scheme for organic thin-film-transistors

    NASA Astrophysics Data System (ADS)

    Fan, Ching-Lin; Shang, Ming-Chi; Hsia, Mao-Yuan; Wang, Shea-Jue; Huang, Bohr-Ran; Lee, Win-Der

    2016-03-01

    A Microwave-Induction Heating (MIH) scheme is proposed for the poly(4-vinylphenol) (PVP) gate insulator cross-linking process to replace the traditional oven heating cross-linking process. The cross-linking time is significantly decreased from 1 h to 5 min by heating the metal below the PVP layer using microwave irradiation. The necessary microwave power was substantially reduced to about 50 W by decreasing the chamber pressure. The MIH scheme is a good candidate to replace traditional thermal heating for cross-linking of PVP as the gate insulator for organic thin-film-transistors.

  7. Laboratory evaluation of different formulations of Stress Coat(®) for slime production in goldfish (Carassius auratus) and koi (Cyprinus carpio).

    PubMed

    Shivappa, Raghunath B; Christian, Larry S; Law, Jerry M; Lewbart, Gregory A

    2017-01-01

    A study was carried out to assess the effect of Stress Coat(®) on slime production in goldfish (Carassius auratus) and koi (Cyprinus carpio). The study also investigated histological changes that might be associated with slime producing cells, and wound healing in koi. Several formulations of Stress Coat(®) were investigated and the results showed that polyvinylpyrrolidone (PVP), also known as povidone, an ingredient of Stress Coat(®), when used alone, showed significantly higher slime production in goldfish than salt and Stress Coat(®) without PVP after 25 h. The results also showed that koi treated with compounds containing PVP showed better wound healing than those not exposed to PVP. Histology results showed no difference between compounds tested with regards to density and number of slime producing cells.

  8. Laboratory evaluation of different formulations of Stress Coat® for slime production in goldfish (Carassius auratus) and koi (Cyprinus carpio)

    PubMed Central

    Shivappa, Raghunath B.; Christian, Larry S.; Law, Jerry M.

    2017-01-01

    A study was carried out to assess the effect of Stress Coat® on slime production in goldfish (Carassius auratus) and koi (Cyprinus carpio). The study also investigated histological changes that might be associated with slime producing cells, and wound healing in koi. Several formulations of Stress Coat® were investigated and the results showed that polyvinylpyrrolidone (PVP), also known as povidone, an ingredient of Stress Coat®, when used alone, showed significantly higher slime production in goldfish than salt and Stress Coat® without PVP after 25 h. The results also showed that koi treated with compounds containing PVP showed better wound healing than those not exposed to PVP. Histology results showed no difference between compounds tested with regards to density and number of slime producing cells. PMID:28894641

  9. [Investigation on composites of europium fluorescent complexes and polyvinylpyrrolidone].

    PubMed

    Hao, Chao-wei; Zhao, Ying; Xu, Yi-zhuang; Wang, Du-jin; Xu, Duan-fu

    2008-09-01

    In order to investigate the relationship between the aggregation structure and fluorescence properties of composites of rare earth fluorescent complexes and polymers, the fluorescent complexes of Eu(TTA)3 x 2H2O and Eu(TTA)3 x (TPPO)2 were synthesized by the reaction of TTA (2-thenoyltrifluoroacetone), TPPO (triphenylphosphine oxide) and EuCl3, and their composites with polyvinylpyrrolidone (PVP K30) were prepared. The fluorescence spectroscopy, FTIR spectroscopy and TEM were used to characterize these composites. Fluorescence spectroscopy results indicated that the fluorescence intensity of the PVP/Eu(TTA)3 x 2H2O composites is obviously improved compared with that of the Eu(TTA)3 x 2H2O complexes. For the composites with the molar ratio of the complexes to the repeat unit of PVP being 1:35, the intensity of 612 nm emission peak of the composites is 5.5 times for PVP/Eu(TTA)3 x 2H2O and 0.3 times for PVP/Eu(TTA)3 x (TPPO)2 higher than that of the corresponding pure rare earth fluorescent complexes. And the emission intensity ratio of 612 to 590 nm peak is 14.7 in PVP/Eu (TTA)3 x 2H2O composite, larger than that of Eu(TTA)3 x 2H2O complexes. These results suggested that the luminescent properties of the europium fluorescent complexes were obviously enhanced in the presence of PVP matrix and there are interactions between the fluorescence complexes and PVP molecules. In the presence of PVPK30, the FTIR spectra of the Eu(TTA)3 x 2H2O complexes were obviously influenced as well. Based on the curve-fitting results of IR spectra of PVP/Eu(TTA)3 2H2O composites with the molar ratio of repeat unit of PVP to Eu(TTA)3 x 2H2O being 7:1 and 2:1, multiple absorption peaks of nu C=O are observed. The IR spectral variations indicated that there are coordination interactions between Eu3+ ions and the carbonyl groups of PVP, and multiple coordination fashion exists. TEM results showed that there are microphase separation structures in PVP/Eu(TTA)3 x 2H2O and PVP/Eu(TTA)3 x (TPPO)2

  10. Chitosan-cross-linked osmium polymer composites as an efficient platform for electrochemical biosensors.

    PubMed

    Jirimali, Harishchandra Digambar; Nagarale, Rajaram Krishna; Lee, Jong Myung; Saravanakumar, Durai; Shin, Woonsup

    2013-07-22

    A new family of chitosan-cross-linked osmium polymer composites was prepared and its electrochemical properties were examined. The composites were prepared by quaternization of the poly(4-vinylpyridine) osmium bipyridyl polymer (PVP-Os) which was then cross-linked with chitosan, yielding PVP-Os/chitosan. Films made of the composites showed improved mass and electron transport owing to the porous and hydrophilic structure which is derived from the cross-links between the Os polymer and chitosan. The rate for glucose oxidation was enhanced four times when glucose oxidase (GOx) was immobilized on PVP-Os/chitosan compared immobilization on PVP-Os. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Effects of video games on adolescents and adults.

    PubMed

    Hart, Gordon M; Johnson, Bryan; Stamm, Brian; Angers, Nick; Robinson, Adam; Lally, Tara; Fagley, William H

    2009-02-01

    The present study compared a sample of American adolescents with a Spanish sample on a measure of video game addiction, the Problem Video Game Playing (PVP) survey developed in Spain. In addition, the study examined excessive video game playing and reported distress in social life, occupational activities, and school among high school students, college students, and adults. Samples taken from a large Eastern university, two suburban high schools, and an Internet survey were surveyed with an instrument developed by the authors and the PVP. Results show support for the PVP and a similarity between the Spanish and American samples but not for relationships between the PVP and assessments of distress in areas of daily functioning.

  12. Fabrication and Optical Properties of Electrospun Conductive Polymer Nanofibers from Blended Polymer Solution

    NASA Astrophysics Data System (ADS)

    Chuangchote, Surawut; Sagawa, Takashi; Yoshikawa, Susumu

    2008-01-01

    Ultrafine poly[2-methoxy-5-(2'-ethylhexyloxy)-1,4-phenylene-vinylene] (MEH-PPV)/poly(vinyl pyrrolidone) (PVP) composite fibers with the average diameters ranging from 43 nm to 1.7 µm were prepared by electrospinning of blended polymer solutions in mixed solvent of chlorobenzene and methanol. The average diameter of the as-spun fibers was found to decrease into nanometer scale with decreasing the PVP concentration and/or addition of a volatile organic salt, pyridinium formate (PF). PVP was easily removed from MEH-PPV/PVP fibers by the Soxhlet extraction, and after the removal, pure MEH-PPV fibers were obtained as a ribbon-like structure aligned with wrinkled surface in fiber direction. Comparison with the cast film, as-spun fibers showed relatively higher crystallinity, higher conjugation length, and there was a remarkable blue shift of photoluminescence (PL) peak.

  13. Polymer blend implant for ocular delivery of fluorometholone.

    PubMed

    Morita, Y; Saino, H; Tojo, K

    1998-01-01

    Ocular implants containing fluorometholone (FLM) were prepared using blends of poly (DL-lactic acid) (PLA) and polyvinyl pyrrolidone (PVP). The effect of the fraction of PVP content on the release of FLM from the implant was investigated in vitro. The drug was released from the device by approximately following first order kinetics within the period of 40 d. The release rate gradually increased with an increase in the PVP content. The in vivo study after implantation in the anterior chamber of rabbit eyes indicated that the PLA-PVP implant showed a good correlation between the in vitro and in vivo release of FLM. The present polymer blend implant demonstrated a constant level of FLM in the aqueous humor for one month.

  14. Fluorescence Sensing of Nitrite Ions on Polyvinylpyrrolidone/Zinc Oxide Composites Prepared by Impregnation Method

    NASA Astrophysics Data System (ADS)

    Yuliati, L.; So'ad, S. Z. M.; Alim, N. S.; Lintang, H. O.

    2017-05-01

    A series of polyvinylpyrrolidone/zinc oxide (PVP/ZnO) composites with different loading amounts of PVP was prepared by an impregnation method. Successful formation of the composites was analyzed by the Fourier transform infrared (FTIR), diffuse reflectance ultraviolet-visible (DR UV-Vis) and fluorescence spectroscopies. Prepared composites were then further tested as fluorescence sensors by conducting quenching studies in the presence of nitrite ions (NO2 -). Among the prepared composites, the ZnO with 1% PVP exhibited the highest sensing performance for the NO2 -detection (Ksv = 0.07 µM-1). The efficiency of the composite was ca. 1.7 and 1.4 times higher than the bare ZnO and the best composite prepared by the physical mixing method, respectively. These results suggested that impregnation method is a suitable method to prepare the PVP/ZnO composites as fluorescence sensor for the NO2 -detection.

  15. Allergic contact dermatitis to copolymers in cosmetics--case report and review of the literature.

    PubMed

    Quartier, Sarah; Garmyn, Marjan; Becart, Sophie; Goossens, An

    2006-11-01

    Copolymers or heteropolymers are large molecules with high molecular weights (>1000 D). They have been underestimated for a long time as to their sensitizing capacities. Allergic contact dermatitis to 6 copolymers in cosmetics and 1 in a medical dressing has been described; however, the nature of the hapten is still unknown. We report a case of allergic contact dermatitis to polyvinylpyrrolidone (PVP)/hexadecene copolymer in a purple-colored lipstick and review the literature on allergic contact dermatitis to 7 copolymers: PVP/hexadecene, PVP/eicosene, PVP/1-triacontene, methoxy polyethyleneglycol (PEG)-22/dodecyl glycols, methoxy PEG-17/dodecyl glycols, phthalic anhydride/trimellitic anhydride/glycols, and polyvinyl methyl/maleic acid anhydride.

  16. Clinical Evaluation of Percutaneous Vertebroplasty in a Patient with Paraplegia and Immobilization Syndrome: A Case Report

    PubMed Central

    Masala, Salvatore; Calabria, Eros; De Vivo, Dominique; Neroni, Luca; Simonetti, Giovanni

    2013-01-01

    We will discuss a potential role of percutaneous vertebroplasty (PVP) in the management of a patient with immobilization syndrome due to paraplegia and vertebral osteoporotic fractures. While PVP is commonly used for the treatment of osteoporotic thoracolumbar vertebral compression fractures, its role in vertebral stabilization in patient with immobilization syndrome has not been reported in the literature. A 73-year-old woman affected by immobilization syndrome due to paraplegia and vertebral osteoporotic fractures was treated with PVP of vertebrae D12, L1, and L4. After PVP, the patient did not need any antalgic therapy, and there was a significant improvement regarding mobilization, performance of physiological functions, daily management of personal care, and treatment of decubitus ulcers, increasing life quality and psychological well-being. PMID:23573449

  17. 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.

  18. Improving polymer nanofiber quality using a modified co-axial electrospinning process.

    PubMed

    Yu, Deng-Guang; Branford-White, Christopher; Bligh, S W Annie; White, Kenneth; Chatterton, Nicholas P; Zhu, Li-Min

    2011-05-18

    Based on a modified coaxial electrospinning process and suitable selection of solvent mixtures as sheath fluid, a new strategy is presented for systematically improving polymer nanofiber quality. A concentric spinneret with an indented inner capillary is designed for the modified coaxial electrospinning. With a solution of 12% w/v PVP K60 in ethanol as the core electrospinning fluid, six solvents are used as sheath fluids to investigate the impact of solvent properties on the resultant PVP nanofiber quality. The PVP nanofiber quality is closely related to solvent physical-chemical properties. High quality PVP nanofibers of average diameter 130 ±10 nm with homogeneous structures and smooth surfaces are created using a solvent mixture of acetone, ethanol and DMAc in the ratio of 3:1:1(v/v/v).

  19. Localized synthesis of polypyrrole in the nanopattern of monolayer films of diblock copolymer micelles.

    PubMed

    Yoo, Seong Il; Sohn, Byeong-Hyeok; Zin, Wang-Cheol; Jung, Jin Chul

    2004-11-23

    A single-layered array of polystyrene-block-poly(4-vinylpyridine), PS-PVP, micelles in hexagonal order, fabricated by spin coating, was employed as a nanostructured template for synthesis of polypyrrole, a conducting polymer, in nanometer-sized domains. Oxidative catalysts of FeCl3 for the polymerization were selectively loaded in spherical PVP nanodamains so that they were hexagonally arranged over the film but confined in the nanometer range. The vapor-phase polymerization of pyrrole was localized in the PVP nanodomains, leading to a morphological transition from spherical to wormlike domains. In addition, the nanodomains containing polypyrrole were converted to open cavities by ethanol, a PVP block-selective solvent.

  20. 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.

  1. Direct electrospinning of Ag/polyvinylpyrrolidone nanocables

    NASA Astrophysics Data System (ADS)

    Song, Jie; Chen, Menglin; Olesen, Mikkel Buster; Wang, Chenxuan; Havelund, Rasmus; Li, Qiang; Xie, Erqing; Yang, Rong; Bøggild, Peter; Wang, Chen; Besenbacher, Flemming; Dong, Mingdong

    2011-12-01

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

  2. Effects of oral exposure to silver nanoparticles on the sperm of rats.

    PubMed

    Lafuente, D; Garcia, T; Blanco, J; Sánchez, D J; Sirvent, J J; Domingo, J L; Gómez, M

    2016-04-01

    It has been demonstrated that exposure to silver nanoparticles (AgNPs) can induce toxicological effects in rodents. In this study, we investigated whether sub-chronic oral exposure to different doses of polyvinil pyrrolidone (PVP)-coated AgNPs (PVP-AgNPs) (50, 100 and 200mg/kg/day) could induce harmful effects on epididymal sperm rat parameters. Sperm motility, viability and morphology were examined. Moreover, a histological evaluation of testis and epididymis was also performed. High doses of PVP-AgNPs showed higher sperm morphology abnormalities, while a progressive, but not significant effect, was observed in other sperm parameters. The current results suggest that oral sub-chronic exposure to PVP-AgNPs induces slight toxicological effects in sperm rat parameters.

  3. Radiation synthesis of N-vinyl 2-pyrrolidone/acrylonitrile interpenetrating polymer networks and their use in uranium recovery from aqueous systems

    NASA Astrophysics Data System (ADS)

    Sahiner, Nurettin; Pekel, Nursel; Güven, Olgun

    1998-06-01

    Interpenetrating Polymer Networks (IPNs) based on Poly n-vinyl 2-pyrrolidone (PVP) and Acrylonitrile (AN) were prepared by irradiating PVP solutions prepared in AN. PVP/AN mixtures were irradiated by 60Co-γ rays at room temperature at a dose rate of 0.5 kGy/hour. IPNs were characterized by using FT-IR and Thermal Analysis techniques. The chelating adsorbents containing amidoxime groups were prepared by the reaction of these IPNs with hydroxylamine in aqueous NaOH solution at 50°C. These amidoxime containing adsorbents were used in adsorption studies for the recovery of uranium from aqueous systems. The adsorption capacity of an IPN with equivolume fraction of PVP and amidoximated PAN was found to be 750mg UO 22+/g dry amidoximated IPN.

  4. Facile Synthesis of Co9Se8 Quantum Dots as Charge Traps for Flexible Organic Resistive Switching Memory Device.

    PubMed

    Zhang, Peng; Xu, Benhua; Gao, Cunxu; Chen, Guilin; Gao, Meizhen

    2016-11-09

    Uniform Co9Se8 quantum dots (CSQDs) were successfully synthesized through a facile solvothermal method. The obtained CSQDs with average size of 3.2 ± 0.1 nm and thickness of 1.8 ± 0.2 nm were demonstrated good stability and strong fluorescence under UV light after being easily dispersed in both of N,N-dimethylformamide (DMF) and deionized water. We demonstrated the flexible resistive switching memory device based on the hybridization of CSQDs and polyvinylpyrrolidone (PVP) (CSQDs-PVP). The device with the Al/CSQDs-PVP/Pt/poly(ethylene terephthalate) (PET) structure represented excellent switching parameters such as high ON/OFF current ratio, low operating voltages, good stability, and flexibility. The flexible resistive switching memory device based on hybridization of CSQDs and PVP has a great potential to be used in flexible and high-performance memory applications.

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

    PubMed

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

    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.

  6. 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.

  7. 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.

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

    PubMed

    Fonteyne, Margot; Fussell, Andrew Luke; Vercruysse, Jurgen; Vervaet, Chris; Remon, Jean Paul; Strachan, Clare; Rades, Thomas; De Beer, Thomas

    2014-02-28

    According to the quality by design principle processes may not remain black-boxes and full process understanding is required. The granule size distribution of granules produced via twin screw granulation is often found to be bimodal. The aim of this study was to gain a better understanding of binder distribution within granules produced via twin screw granulation in order to investigate if an inhomogeneous spread of binder is causing this bimodal size distribution. Theophylline-lactose-polyvinylpyrrolidone K30 (PVP) (30-67.5-2.5%, w/w) was used as a model formulation. The intra-granular distribution of PVP was evaluated by means of hyperspectral coherent anti-Stokes Raman scattering (CARS) microscopy. For the evaluated formulation, no PVP rich zones were detected when applying a lateral spatial resolution of 0.5 μm, indicating that PVP is homogenously distributed within the granules.

  9. Investigation of the Ionic conductivity and dielectric measurements of poly (N-vinyl pyrrolidone)-sulfamic acid polymer complexes

    NASA Astrophysics Data System (ADS)

    Daries Bella, R. S.; Karthickprabhu, S.; Maheswaran, A.; Amibika, C.; Hirankumar, G.; Devaraj, Premanand

    2015-02-01

    Polymer electrolyte complexes of poly (N-vinyl pyrrolidone) (PVP)-sulfamic acid (NH2SO3H) were prepared by a familiar solution casting method with different molar concentrations of PVP and sulfamic acid. The interaction between PVP and NH2SO3H was confirmed by Fourier transform infrared spectroscopy analysis. Laser microscopy analysis was used to study the surface morphology of the polymer complexes. The glass transition temperature (Tg) and the melting temperature (Tm) of polymer complexes were computed from Differential scanning calorimetric studies. AC impedance spectroscopic measurements revealed that the polymer complex, 97 mol% PVP-3 mol% NH2SO3H shows higher ionic conductivity with two different activation energies above and below the glass transition temperature (Tg). Dielectric studies confirmed that the dc conduction mechanism has dominated in the polymer complexes. The value of power law exponent (n) confirmed the translational motion of ions from one site to another vacant site in these complexes.

  10. Subcutaneous administration of collagen-polyvinylpyrrolidone down regulates IL-1beta, TNF-alpha, TGF-beta1, ELAM-1 and VCAM-1 expression in scleroderma skin lesions.

    PubMed

    Furuzawa-Carballeda, J; Krötzsch, E; Barile-Fabris, L; Alcalá, M; Espinosa-Morales, R

    2005-01-01

    In this study the effect of collagen-polyvinylpyrrolidone (collagen-PVP) vs. triamcinolone acetonide (Triam) in scleroderma (SSc) skin lesions was evaluated. Ten SSc patients were treated weekly with subcutaneous injections of 0.2 mL Triam (8 mg/mL) or 0.2 mL collagen-PVP (1.66 mg collagen). Skin biopsies were obtained from lesions before and after treatment. Tissue sections were evaluated by histology and immunohistochemistry (ELAM-1, VCAM-1, IL-1beta, TNF-alpha, TGF-beta1 and PDGF). The corticoid-treated group showed abnormal tissue architecture while the biodrug-treatment restored cutaneous appendages and type I/III collagen proportion. Cytokine and adhesion molecule expression was almost inhibited with Triam, while collagen-PVP down-regulated it. Collagen-PVP improved the tissue architecture of SSc lesions and down-regulated some proinflammatory parameters, without the side effects induced by corticoids.

  11. The influence of the polymer-stabilizer molecular weight on the spectral luminescence properties of composite sols and coatings containing PbS quantum dots

    NASA Astrophysics Data System (ADS)

    Evstrop'ev, K. S.; Dukel'skii, K. V.; Gatchin, Yu. A.; Evstrop'ev, S. K.; Bondarenko, I. B.

    2016-12-01

    The influence of the polyvinylpyrrolidone (PVP) molecular weight on the stability and spectral luminescence properties of sols of lead sulfide nanocrystals and the related composite coatings has been studied. It is shown that the spectral properties of PbS sols stabilized with low-molecular (PVP) and the related coatings are determined to a great extent by the formation of large particle aggregates in these materials and, accordingly, high level of light scattering. It is effective to use low-molecular PVP for preparing powder materials containing PbS quantum dots (QDs), because it allows one to perform fast powder precipitation and form small semiconductor particles. High-molecular PVP provides high aggregative and sedimentation stabilities of semiconductor nanocrystal sols. This polymer is effective for use in preparing stable QD sols and homogeneous coatings transparent in the visible spectral range.

  12. 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.

  13. Studies on the effect of polyvinyl pyrrolidone on the activity of chlorhexidine mouthrinses: plaque and stain.

    PubMed

    Claydon, N; Addy, M; Jackson, R; Smith, S; Newcombe, R G

    2001-06-01

    Polyvinyl pyrrolidone (PVP) was shown in vitro to reduce chlorhexidine induced, dietary staining without affecting the uptake of the antiseptic to the test substrate. The aim of these studies in vivo was to determine whether PVP affected plaque and dietary staining by a low concentration chlorhexidine rinse. The plaque and stain studies used a double blind, randomised 6, treatment crossover design involving healthy subjects with a high standard of oral hygiene and gingival health. The rinse formulations under test were: (A) aqueous alcohol (placebo control), (B) 0.03% chlorhexidine, (C) 0.06% chlorhexidine, (D) 0.06% chlorhexidine+1.2% PVP, (E) 0.06% chlorhexidine+5% PVP, (F) 0.06% chlorhexidine+10% PVP. In the plaque study, on day 1 of each period, subjects were rendered plaque free and then rinsed with 15 ml of the test rinse for 60 s. No further tooth cleaning was performed and subjects returned 24 h later for plaque scoring by area. In the stain study, on day 1 of each period, the tongue and teeth of each subject were rendered stain free. Subjects then rinsed under supervision for 60 s with 15 ml of the allocated rinse 8 x a day between 09:00 h and 17:00 h for 3 days. Immediately after each rinse with the test formulation, subjects rinsed for 120 s with 15 ml of warm black tea. Subjects were requested to also drink at least 5 cups of tea or coffee per day. On day 4, stain was scored by area and intensity from designated teeth and dorsum of the tongue. Washout periods were at least 7 days in both studies. Plaque areas were greatest with placebo and least with 0.06% chlorhexidine. Plaque scores increased with increasing concentrations of PVP in the 0.06% chlorhexidine rinse and were significantly higher than 0.06% chlorhexidine without PVP rinse. Tooth stain areas were comparable for placebo, 0.03% and 0.06% chlorhexidine rinses, but significantly reduced with the PVP/chlorhexidine rinses compared to the 0.06% chlorhexidine rinse. Tooth stain intensity was

  14. The cellular and genomic response of rat dopaminergic neurons (N27) to coated nanosilver.

    PubMed

    Chorley, Brian; Ward, William; Simmons, Steven O; Vallanat, Beena; Veronesi, Bellina

    2014-12-01

    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 (0.5-5 ppm) to a set of nanoAg of different sizes (10nm, 75 nm) and coatings (PVP, citrate) and their physicochemical, cellular and genomic response measured. Both coatings retained their manufactured sizes in culture media, however, the zeta potentials of both sizes of PVP-coated nanoAg were significantly less electronegative than those of their citrate-coated counterparts. Markers of oxidative stress, measured at 0.5-5 ppm exposure concentrations, indicated that caspase 3/7 activity and glutathione levels were significantly increased by both sizes of PVP-coated nanoAg and by the 75 nm citrate-coated nanoAg. Both sizes of PVP-coated nanoAg also increased intra-neuronal nitrite levels and activated ARE/NRF2, a reporter gene for the oxidative stress-protection pathway. Global gene expression on N27 neurons, exposed to 0.5 ppm for 8h, indicated a dominant effect by PVP-coated nanoAg over citrate. The 75 nm PVP-coated material altered 196 genes that were loosely associated with mitochondrial dysfunction. In contrast, the 10nm PVP-coated nanoAg altered 82 genes that were strongly associated with NRF2 oxidative stress pathways. Less that 20% of the affected genes were shared by both sizes of PVP-coated nanoAg. These cellular and genomic findings suggest that PVP-coated nanoAg is more bioactive than citrate-coated nanoAg. Although both sizes of PVP-coated nanoAg altered the genomic expression of N27 neurons along oxidative stress pathways, exposure to the 75 nm nanoAg favored pathways associated with mitochondrial dysfunction, whereas the 10nm PVP-coated nanoAg affected NRF2 neuronal protective pathways.

  15. 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

  16. Elucidation of the internal physical and chemical microstructure of pharmaceutical granules using X-ray micro-computed tomography, Raman microscopy and infrared spectroscopy.

    PubMed

    Crean, Barry; Parker, Andrew; Roux, Delphine Le; Perkins, Mark; Luk, Shen Y; Banks, Simon R; Melia, Colin D; Roberts, Clive J

    2010-11-01

    X-ray micro-computed tomography (XMCT) was used in conjunction with confocal Raman mapping to measure the intra-granular pore size, binder volumes and to provide spatial and chemical maps of internal granular components in α-lactose monohydrate granules formulated with different molecular weights of polyvinyl pyrrolidone (PVP). Infrared spectroscopy was used to understand the molecular association of binder domains. Granules were prepared by high-shear aqueous granulation from α-lactose monohydrate and PVP K29/32 or K90. XMCT was used to visualise the granule microstructure, intra-granular binder distribution and measure intra-granular porosity, which was subsequently related to intrusion porosimetry measurements. Confocal Raman microscopy and infrared microscopy were employed to investigate the distribution of components within the granule and explore the nature of binder substrate interactions. XMCT data sets of internal granule microstructure provided values of residual porosity in the lactose:PVP K29/32 and lactose:PVP K90 granules of 32.41 ± 4.60% and 22.40 ± 0.03%, respectively. The binder volumes of the lactose:PVP K29/32 and lactose:PVP K90 granules were 2.98 ± 0.10% and 3.38 ± 0.07%, respectively, and were attributed to PVP-rich binder domains within the granule. Confocal Raman microscopy revealed anisotropic domains of PVP between 2 μm and 20 μm in size surrounded by larger particles of lactose, in both granule types. Raman data showed that PVP domains contained various amounts of lactose, whilst IR microscopy determined that the PVP was molecularly associated with lactose, rather than residual water. The work shows that XMCT can be applied to investigate granular microstructure and resolve the porosity and the excipient and binder volumes. Combining this technique with vibrational techniques provides further structural information and aids the interpretations of the XMCT images. When used complementarily, these techniques highlighted that

  17. Development of spray-dried co-precipitate of amorphous celecoxib containing storage and compression stabilizers.

    PubMed

    Dhumal, Ravindra S; Shimpi, Shamkant L; Paradkar, Anant R

    2007-09-01

    The purpose of this study was to obtain an amorphous system with minimum unit operations that will prevent recrystallization of amorphous drugs since preparation, during processing (compression) and further storage. Amorphous celecoxib, solid dispersion (SD) of celecoxib with polyvinyl pyrrollidone (PVP) and co-precipitate with PVP and carrageenan (CAR) in different ratios were prepared by the spray drying technique and compressed into tablets. Saturation solubility and dissolution studies were performed to differentiate performance after processing. Differential scanning calorimetry and X-ray powder difraction revealed the amorphous form of celecoxib, whereas infrared spectroscopy revealed hydrogen bonding between celecoxib and PVP. The dissolution profile of the solid dispersion and co-precipitate improved compared to celecoxib and amorphous celecoxib. Amorphous celecoxib was not stable on storage whereas the solid dispersion and co-precipitate powders were stable for 3 months. Tablets of the solid dispersion of celecoxib with PVP and physical mixture with PVP and carrageenan showed better resistance to recrystallization than amorphous celecoxib during compression but recrystallized on storage. However, tablets of co-precipitate with PVP and carageenan showed no evidence of crystallinity during stability studies with comparable dissolution profiles. This extraordinary stability of spray-dried co-precipitate tablets may be attributed to the cushioning action provided by the viscoelastic polymer CAR and hydrogen bonding interaction between celecoxib and PVP. The present study demonstrates the synergistic effect of combining two types of stabilizers, PVP and CAR, on the stability of amorphous drug during compression and storage as compared to their effect when used alone.

  18. Antisolvent precipitation technique: A very promising approach to crystallize curcumin in presence of polyvinyl pyrrolidon for solubility and dissolution enhancement.

    PubMed

    Sadeghi, Fatemeh; Ashofteh, Mohammad; Homayouni, Alireza; Abbaspour, Mohammadreza; Nokhodchi, Ali; Garekani, Hadi Afrasiabi

    2016-11-01

    Curcumin with a vast number of pharmacological activities is a poorly water soluble drug which its oral bioavailability is profoundly limited by its dissolution or solubility in GI tract. Curcumin could be a good anticancer drug if its solubility could be increased. Therefore, the aim of the present study was to increase the dissolution rate of curcumin by employing antisolvent crystallization technique and to investigate the effect of polyvinyl pyrrolidone K30 (PVP) as colloidal particles in crystallization medium on resultant particles. Curcumin was crystalized in the presence of different amounts of PVP by antisolvent crystallization method and their physical mixtures were prepared for comparison purposes. The samples were characterized by scanning electron microscopy (SEM), differential scanning calorimetry (DSC), X-ray powder diffraction (XRPD) and Fourier transform infrared spectroscopy (FT-IR). The solubility and dissolution of the treated and untreated curcumin were also determined. Antisolvent crystallization of curcumin led to the formation of particles with no definite geometric shape. It was interesting to note that the DSC and XRPD studies indicated the formation of a new polymorph and less crystallinity for particles crystallized in the absence of PVP. However, the crystallized curcumin in the presence of PVP was completely amorphous. All crystalized curcumin samples showed much higher dissolution rate compared to untreated curcumin. The amount of curcumin dissolved within 10 for treated curcumin in the presence of PVP (1:1 curcumin:PVP) was 7 times higher than untreated curcumin and this enhancement in the dissolution for curcumin samples crystallized in the absence of PVP was around 5 times. Overall' the results of this study showed that antisolvent crystallization method in the absence or presence of small amounts of PVP is very efficient in increasing the dissolution rate of curcumin to achieve better efficiency for curcumin.

  19. Influence of extreme concentrations of hydrophilic pore-former on reinforced polyethersulfone ultrafiltration membranes for reduction of humic acid fouling.

    PubMed

    Son, Moon; Kim, Hayoung; Jung, Junhyeok; Jo, Sungsoo; Choi, Heechul

    2017-07-01

    To address the issue of membrane fouling by ubiquitous humic substances, a hydrophilic pore-former-blended polyethersulfone UF membrane was successfully synthesized via the phase inversion method. For the first time, extremely high concentrations of polyvinylpyrrolidone (PVP), up to 20 wt%, were tested as the hydrophilic pore-former in order to determine the optimum concentration for humic acid fouling. Intrinsic membrane parameters such as permeability and selectivity were evaluated using a cross-flow UF filtration setup. Interestingly, as little as 1 wt% added PVP can significantly improve membrane permeability. That tiny amount of added PVP increased membrane flux to 1107 L/m(2)h·bar from zero flux, with over 90% rejection of humic acid. In addition, pure water permeation increased to over 2400 L/m(2)h·bar without sacrificing humic acid rejection (around 90%) when 10 wt% PVP was added; pure water permeation decreased to around 1000 L/m(2)h·bar as added PVP was increased to 20 wt%. The order of water flux increased with the amount of added PVP up to 20 wt% during humic acid fouling while maintaining membrane selectivity. However, the membrane with 10 wt% added PVP showed the best fouling resistance in terms of flux recovery ratio (98%), total flux loss, reversible fouling ratio, and irreversible fouling ratio. Therefore, the addition of 10 wt% PVP is recommended considering cleaning efficiency and the moderately high flux during humic acid fouling for field operation in wastewater reclamation and water treatment processes. Copyright © 2017 Elsevier Ltd. All rights reserved.

  20. Preformulation and Formulation Investigational New Drugs

    DTIC Science & Technology

    1990-07-01

    Hydrogenated Castor Oil; waxy material with a melting point of 85-88 0 C PVP K30 conforms to USP XXI requirements for Povidone ; K30 is a water soluble...with various grades of hydroxypropylmethyl- cellulose (Methocel® K4M, K15M or KlOOM), hydrogenated castor oil (Castorwax4D), polyvinylpyrrolidonn (PVP... Povidone @, Plasdoneg or KollidonO) and other excipients. Extended release over 6-12 hours was desired from such formulations. Release characteristics

  1. Prominent periventricular fiber system related to ganglionic eminence and striatum in the human fetal cerebrum.

    PubMed

    Vasung, L; Jovanov-Milošević, N; Pletikos, M; Mori, S; Judaš, M; Kostović, Ivica

    2011-01-01

    Periventricular pathway (PVP) system of the developing human cerebrum is situated medial to the intermediate zone in the close proximity to proliferative cell compartments. In order to elucidate chemical properties and developing trajectories of the PVP we used DTI in combination with acetylcholinesterase histochemistry, SNAP-25 immunocytochemistry and axonal cytoskeletal markers (SMI312, MAP1b) immunocytochemistry on postmortem paraformaldehyde-fixed brains of 30 human fetuses ranging in age from 10 to 38 postconceptional weeks (PCW), 2 infants (age 1-3 months) and 1 adult brain. The PVP appears in the early fetal period (10-13 PCW) as two defined fibre bundles: the corpus callosum (CC) and the fetal fronto-occipital fascicle (FOF). In the midfetal period (15-18 PCW), all four components of the PVP can be identified: (1) the CC, which at rostral levels forms a voluminous callosal plate; (2) the FOF, with SNAP-25-positive fibers; (3) the fronto-pontine pathway (FPP) which for a short distance runs within the PVP; and (4) the subcallosal fascicle of Muratoff (SFM) which contains cortico-caudate projections. The PVPs are situated medial to the internal capsule at the level of the cortico-striatal junction; they remain prominent during the late fetal and early preterm period (19-28 PCW) and represent a portion of the wider periventricular crossroad of growing associative, callosal and projection pathways. In the perinatal period, the PVPs change their topographical relationships, decrease in size and the FOF looses its SNAP-25-reactivity. In conclusion, the hitherto undescribed PVP of the human fetal cerebrum contains forerunners of adult associative and projection pathways. Its transient chemical properties and relative exuberance suggest that the PVP may exert influence on the development of cortical connectivity (intermediate targeting) and other neurogenetic events such as neuronal proliferation. The PVP's topographical position also indicates that it is a major

  2. Research and Development of Wound Dressing in Maxillofacial Trauma.

    DTIC Science & Technology

    1982-06-23

    Biological and Medical Sciences - Pharmacology Wound healing Hemostatics Polymers Local anesthetics Encapsulating Polylactide Antiinfectives and...44 iv LIST OF FIGURES Page Figure 1 Gel Permeation Chromatograms 8 Figure 2 SEMs of PVP.1 2- Polylactide Fabric Showing 21 Structural Difference as...Drug Concentration is Increased Figure 3 SEMs of PVP.12 - Polylactide Powder of 20% Drug 23 (212-300 microns) Showing structure of Fractured Surface

  3. Poly(vinylpyrrolidone): a new reductant for preparation of tellurium nanorods, nanowires, and tubes from TeO2

    NASA Astrophysics Data System (ADS)

    Zhu, Ying-Jie; Hu, Xian-Luo; Wang, Wei-Wei

    2006-02-01

    A new approach has been developed for the preparation of tellurium with various morphologies by a simple hydrothermal method using TeO2 and poly(vinylpyrrolidone) (PVP). In this method, PVP acts not only as a surfactant but also as a reducing reagent, thus no additional reductants are needed. By control of the reaction conditions, tellurium nanorods, nanowires, and tubes have been prepared. Our experiments showed that pyrrole and polyethylene glycol (PEG) can also be used as reducing reagents.

  4. Comparative Analysis of the Paravertebral Analgesic Pump Catheter with the Epidural Catheter in Elderly Trauma Patients with Multiple Rib Fractures.

    PubMed

    Shapiro, Brian S; Wasfie, Tarik; Chadwick, Mathew; Barber, Kimberly R; Yapchai, Raquel

    2017-04-01

    Presently, trauma guidelines recommend epidural analgesia as the optimal modality of pain relief from rib fractures. They are not ideally suited for elderly trauma patients and have disadvantages including bleeding risk. The paravertebral analgesic pump (PVP) eliminates such disadvantages and includes ease of placement in the trauma setting. This study compares pain control in patients treated by EPI versus PVP. This is a retrospective, historical cohort study comparing two methods of pain management in the trauma setting. Before 2010, patients who had epidural catheters (EPI) placed for pain control were compared with patients after 2010 in which the PVP was used. All patients had multiple rib fractures as diagnosed by CT scan. Analysis was adjusted for age, number of fractures, and comorbid conditions. Multiple linear regression analysis was conducted to compare average reported pain. A total of 110 patients, 31 PVP and 79 epidural catheters, were included in the study. Overall mean age was 65 years. The mean Injury Severity Score was 12.0 (EPI) and 11.1 (PVP). Mean number rib fractures was 4.29 (EPI) and 4.71 (PVP). PVP was associated with a 30 per cent greater decrease in pain than that seen with EPI (6.0-1.9 vs 6.4-3.4). After controlling for age, Injury Severity Score, and number of rib fractures, there were no differences in intensive care unit or total length of stay (P = 0.35) or in pain score (3.76 vs 3.56, P = 0.64). In conclusion, the PVP compares well with epidural analgesia in older trauma patients yet is safe, well tolerated, and easily inserted.

  5. Research and Development of Wound Dressing in Maxillofacial Trauma.

    DTIC Science & Technology

    1983-03-14

    Lidocaine 7 Table 4 PVP-1 2 (BASF 17/12) Microcapsule Size Distribution 8 Table 5 Processing Summary of PVP-1 2 (BASF 17/12) Microencapsulation 9 Table...benzalkonium chloride (Maquat LC-12S) was also incorporated into fabrics and powders. The povidone iodine (BASF 17/12) was microencapsulated using the... microcapsules con- taining povidone iodine. At 30% polymer, 70% of the product was between :- 212-600 microns. This material gave in vitro release of

  6. Fabrication of channel waveguides from sol-gel-processed polyvinylpyrrolidone/ SiO(2) composite materials.

    PubMed

    Yoshida, M; Prasad, P N

    1996-03-20

    Sol-gel-processed composite materials of polyvinylpyrrolidone (PVP) and SiO(2) were studied for optical waveguide applications. PVP is a polymer that can be crosslinked, so it is expected to have high thermal stability after crosslinking. However, thermal crosslinking and thermal decomposition of pure PVP take place around the same temperature, 200 °C, therefore pure PVP had a high optical propagation loss as a result of the absorption of the decomposed molecules after crosslinking. The incorporation of sol-gel-processed SiO(2) prevented the thermal decomposition of PVP and provided remarkably low optical propagation losses. The PVP/SiO(2)composite material also produced thick (>2-µm) crack-free films when the PVP concentration was 50% or higher. An optical propagation loss of 0.2 dB/cm was achieved at 633 nm in the 50% PVP/SiO(2) composite planar waveguide. Several aspects of the thermal stability of the waveguides were evaluated. The slab waveguide was then used for fabrication of channel waveguides with a selective laser-densification technique. This technique used metal lines fabricated with photolithography on the slab waveguide as a light absorbent, and these metal lines were heated by an Ar laser. The resultant channel waveguide had an optical propagation loss of 0.9 dB/ cm at 633 nm. This technique provides lower absorption loss and scattering loss compared with the direct laser-densification technique, which uses UV lasers, and produces narrow waveguides that are difficult to fabricate with a CO(2) laser.

  7. Rheological performance of bacterial cellulose based nonmineralized and mineralized hydrogel scaffolds

    NASA Astrophysics Data System (ADS)

    Basu, Probal; Saha, Nabanita; Bandyopadhyay, Smarak; Saha, Petr

    2017-05-01

    Bacterial cellulose (BC) based hydrogels (BC-PVP and BC-CMC) are modified with β-tri-calcium phosphate (β-TCP) and hydroxyapatite (HA) to improve the structural and functional properties of the existing hydrogel scaffolds. The modified hydrogels are then biomineralized with CaCO3 following liquid diffusion technique, where salt solutions of Na2CO3 (5.25 g/100 mL) and CaCl2 (7.35 g/100 mL) were involved. The BC-PVP and BC-CMC are being compared with the non-mineralized (BC-PVP-β-TCP/HA and BC-CMC-β-TCP/HA) and biomineralized (BC-PVP-β-TCP/HA-CaCO3 and BC-CMC-β-TCP/HA-CaCO3) hydrogels on the basis of their structural and rheological properties. The Fourier Transform Infrared (FTIR) spectral analysis demonstrated the presence of BC, CMC, PVP, β-TCP, HA in the non-mineralized and BC, CMC, PVP, β-TCP, HA and CaCO3 in the biomineralized samples. Interestingly, the morphological property of non-mineralized and biomineralized, hydrogels are different than that of BC-PVP and BC-CMC based novel biomaterials. The Scanning Electron Microscopic (SEM) images of the before mentioned samples reveal the denser structures than BC-PVP and BC-CMC, which exhibits the changes in their pore sizes. Concerning rheological analysis point of view, all the non-mineralized and biomineralized hydrogel scaffolds have shown significant elastic property. Additionally, the complex viscosity (η*) values have also found in decreasing order with the increase of angular frequency (ω) 0.1 rad.sec-1 to 100 rad.sec-1. All these BC based hydrogel scaffolds are elastic in nature, can be recommended for their application as an implant for bone tissue engineering.

  8. Influence of topical iodine-containing antiseptics used during delivery on recall rate of congenital hypothyroidism screening program.

    PubMed

    Valizadeh, Majid; Moezzi, Farzaneh; Khavassi, Zohreh; Movahedinia, Mohammad; Mazloomzadeh, Seideh; Mehran, Ladan

    2017-08-28

    The proportion of newborns recalled during neonatal screening programs for congenital hypothyroidism (CH) varies substantially by country and may be higher in settings where povodine iodine (PVP-I) is used during delivery. We assessed this hypothesis by substituting PVP-I for chlorhexidine (CHL) and evaluated the reduction in the recall rate of the Irainian newborn screening program. This study investigated 2282 neonates of mothers admitted to a local hospital for delivery between December 2012 and October 2013. We measured thyorid stimulating hormone (TSH) levels in heel-prick blood specimens of infants, aged between 3 and 5 days, born to mothers who received PVP-I (phase I) and those who received CHL after withdrawal of PVP-I from obstetric procedures (phase II). Then we compared the median TSH levels and the recall rate based on a TSH level ≥5 mU/L. Of 2282 cases, 1094 infants were born to mothers exposed to PVP-I during phase I (PVP-I group) and 1188 ones were born to mothers exposed to chlorhexidine in phase II (CHL group); 6.56% of the PVP-I group and 1.91% of the CHL group were recalled later during screening (p<0.001). The median TSH level was significantly higher in the PVP-I group compared to the CHL group (1.35 vs. 1.00, p<0.001). Replacement of iodine-containing antiseptics by iodine-free ones, during delivery resulted in a significant reduction in the recall rate of the Iranian screening program for CH.

  9. 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.

  10. Measles Virus Nucleocapsid (MJVNP) Gene Expression and RANK Receptor Signaling in Osteoclast Precursors. Osteoclast Inhibitors Peptide Therapy for Pagets Disease

    DTIC Science & Technology

    2005-10-31

    Determine the sensitivity of MVNP transduced osteoclast precursors to RANK Ligand (RANKL) and TNF- alpha stimulation to form pagetic osteoclasts. -- Paget’s...herpesvirus (CLONTECH) (pVP16- hVDR) (13). To examine the interaction of TAFII-17 and VDR, 0.5 g of pM-TAFII-17, 0.5 g of pVP -16-hVDR, and 0.5 g of

  11. Dual-Enzyme Characteristics of Polyvinylpyrrolidone-Capped Iridium Nanoparticles and Their Cellular Protective Effect against H2O2-Induced Oxidative Damage.

    PubMed

    Su, Hua; Liu, Dan-Dan; Zhao, Meng; Hu, Wei-Liang; Xue, Shan-Shan; Cao, Qian; Le, Xue-Yi; Ji, Liang-Nian; Mao, Zong-Wan

    2015-04-22

    Polyvinylpyrrolidone-stabilized iridium nanoparticles (PVP-IrNPs), synthesized by the facile alcoholic reduction method using abundantly available PVP as protecting agents, were first reported as enzyme mimics showing intrinsic catalase- and peroxidase-like activities. The preparation procedure was much easier and more importantly, kinetic studies found that the catalytic activity of PVP-IrNPs was comparable to previously reported platinum nanoparticles. Transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS) characterization indicated that PVP-IrNPs had the average size of approximately 1.5 nm and mainly consisted of Ir(0) chemical state. The mechanism of PVP-IrNPs' dual-enzyme activities was investigated using XPS, Electron spin resonance (ESR) and cytochrome C-based electron transfer methods. The catalase-like activity was related to the formation of oxidized species Ir(0)@IrO2 upon reaction with H2O2. The peroxidase-like activity originated from their ability acting as electron transfer mediators during the catalysis cycle, without the production of hydroxyl radicals. Interestingly, the protective effect of PVP-IrNPs against H2O2-induced cellular oxidative damage was investigated in an A549 lung cancer cell model and PVP-IrNPs displayed excellent biocompatibility and antioxidant activity. Upon pretreatment of cells with PVP-IrNPs, the intracellular reactive oxygen species (ROS) level in response to H2O2 was decreased and the cell viability increased. This work will facilitate studies on the mechanism and biomedical application of nanomaterials-based enzyme mimic.

  12. 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.

  13. Antifouling and antimicrobial polymer membranes based on bioinspired polydopamine and strong hydrogen-bonded poly(N-vinyl pyrrolidone).

    PubMed

    Jiang, Jinhong; Zhu, Liping; Zhu, Lijing; Zhang, Hongtao; Zhu, Baoku; Xu, Youyi

    2013-12-26

    A facile and versatile approach for the preparation of antifouling and antimicrobial polymer membranes has been developed on the basis of bioinspired polydopamine (PDA) in this work. It is well-known that a tightly adherent PDA layer can be generated over a wide range of material surfaces through a simple dip-coating process in dopamine aqueous solution. The resulting PDA coating is prone to be further surface-tailored and functionalized via secondary treatments because of its robust reactivity. Herein, a typical hydrophobic polypropylene (PP) porous membrane was first coated with a PDA layer and then further modified by poly(N-vinyl pyrrolidone) (PVP) via multiple hydrogen-bonding interactions between PVP and PDA. Data of water contact angle measurements showed that hydrophilicity and wettability of the membranes were significantly improved after introducing PDA and PVP layers. Both permeation fluxes and antifouling properties of the modified membranes were enhanced as evaluated in oil/water emulsion filtration, protein filtration, and adsorption tests. Furthermore, the modified membranes showed remarkable antimicrobial activity after iodine complexation with the PVP layer. The PVP layer immobilized on the membrane had satisfying long-term stability and durability because of the strong noncovalent forces between PVP and PDA coating. The strategy of material surface modification reported here is substrate-independent, and applicable to a broad range of materials and geometries, which allows effective development of materials with novel functional coatings based on the mussel-inspired surface chemistry.

  14. Pattern guided structure formation in polymer films of asymmetric blends

    NASA Astrophysics Data System (ADS)

    Raczkowska, J.; Bernasik, A.; Budkowski, A.; Cyganik, P.; Rysz, J.; Raptis, I.; Czuba, P.

    2006-03-01

    Two off-critical blends of poly(2-vinylpyridine) and polystyrene, 2:3 and 3:2 (w:w) PVP:PS, were spin-cast (with varied domain scale R) onto periodically ( λ = 4 μm) patterned substrate. The pattern consisted of two alternating symmetric stripes: Au attracting PVP and neutral self-assembled monolayer. The resulting droplet-type morphologies were recorded with Scanning Force Microscopy and examined with integral geometry approach. PVP-rich islands of the 2:3 PVP:PS films form, for a wide R/ λ range, strongly anisotropic morphologies. They show up, for R/ λ ˜ 0.5, a weak λ/2-substructure of smaller PVP droplets in addition to the domains periodic with λ. The 3:2 blend exhibits morphologies with dominant λ-structure of PVP ribbons, which encircle PS droplets. For R/ λ ˜ 0.5, smaller PS domains are also present but no λ/2-substructure is formed. The | χE|-values of droplet surface density are reduced, as compared to homogeneous substrate, for the 3:2 blend (with | χE| → 0 for R ˜ λ). This effect is absent for the 2:3 mixture.

  15. 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.

  16. Assessment of the transport of polyvinylpyrrolidone-stabilised zero-valent iron nanoparticles in a silica sand medium

    NASA Astrophysics Data System (ADS)

    Liang, Bin; Xie, Yingying; Fang, Zhanqiang; Tsang, Eric Pokeung

    2014-07-01

    Nano zero-valent iron has been considered a promising material for in situ remediation, but its strong tendency to form aggregates makes it difficult to transport in porous media. Thus, stabilization techniques are required to overcome this limitation. In this study, we use polyvinylpyrrolidone (PVP) to synthesise to stabilise iron nanoparticles. The effects of various factors such as nZVI influent concentrations, flow velocity, Ca2+, Mg2+ and humic acid on the transport behaviour of the PVP-nZVI particles were considered. A sedimentation test indicated that PVP-nZVI particles with diameters ranging from 50 to 80 nm were more stable than Bare-nZVI particles. Column experiments demonstrated that PVP-nZVI also exhibited better mobility in silica sand than Bare-nZVI. Due to either the straining or blocking effect, the effluent relative concentration ( C/ C 0) plateau increased with increasing particle concentration. Increasing the flow velocity increased the C/ C 0, resulting in the reduction of overall single-collector contact efficiency ( η 0). Humic acid (HA) enhanced the mobility of PVP-nZVI, and the sedimentation test in the presence of HA suggested that decreased attachment of PVP-nZVI to the silica sand surface rather than decreased aggregation was the primary mechanism of this enhanced mobility.

  17. Towards an understanding of adsorption behaviour in non-aqueous systems: adsorption of poly(vinyl pyrrolidone) and poly(ethylene glycol) onto silica from 2H, 3H-perfluoropentane.

    PubMed

    Paul, Alison; Griffiths, Peter C; Rogueda, Philippe G

    2005-11-01

    The adsorption behaviour of low molecular weight poly(ethylene glycol) (PEG 600) and poly(vinyl pyrrolidone) (PVP K25) to silica particles has been investigated at room temperature (21 degrees C) in the partially fluorinated solvent 2H,3H-perfluoropentane (HPFP). PVP (absorbed amount, Gamma = 12 mg g(-1)) was found to adsorb more strongly than PEG (Gamma = 4 mg g(-1)). Both of these values were higher than observed in water. In a further distinction to the aqueous case, where PVP displaces PEG from the interface, no competitive adsorption effects were observed between these two polymers in HPFP, with the adsorbed amounts of each polymer being unchanged by the presence of the other. The stability of silica suspensions in HPFP was primarily dependent on the presence of PVP; PEG/silica systems were unstable, but PVP/silica and PEG/PVP/silica systems formed stable suspensions. All suspensions were destabilized by the addition of small (0.15 wt%) amounts of water. The observations made in this work would point to a flocculation phenomenon due to the addition of water, and not Ostwald ripening. The mechanism of this destabilization is likely to be water acting as a flocculation bridge between particles.

  18. Hydrogen Bonding Interactions in Amorphous Indomethacin and Its Amorphous Solid Dispersions with Poly(vinylpyrrolidone) and Poly(vinylpyrrolidone-co-vinyl acetate) Studied Using (13)C Solid-State NMR.

    PubMed

    Yuan, Xiaoda; Xiang, Tian-Xiang; Anderson, Bradley D; Munson, Eric J

    2015-12-07

    Hydrogen bonding interactions in amorphous indomethacin and amorphous solid dispersions of indomethacin with poly(vinylpyrrolidone), or PVP, and poly(vinylpyrrolidone-co-vinyl acetate), or PVP/VA, were investigated quantitatively using solid-state NMR spectroscopy. Indomethacin that was (13)C isotopically labeled at the carboxylic acid carbon was used to selectively analyze the carbonyl region of the spectrum. Deconvolution of the carboxylic acid carbon peak revealed that 59% of amorphous indomethacin molecules were hydrogen bonded through carboxylic acid cyclic dimers, 15% were in disordered carboxylic acid chains, 19% were hydrogen bonded through carboxylic acid and amide interactions, and the remaining 7% were free of hydrogen bonds. The standard dimerization enthalpy and entropy of amorphous indomethacin were estimated to be -38 kJ/mol and -91 J/(mol · K), respectively, using polystyrene as the "solvent". Polymers such as PVP and PVP/VA disrupted indomethacin self-interactions and formed hydrogen bonds with the drug. The carboxylic acid dimers were almost completely disrupted with 50% (wt) of PVP or PVP/VA. The fraction of disordered carboxylic acid chains also decreased as the polymer content increased. The solid-state NMR results were compared with molecular dynamics (MD) simulations from the literature. The present work highlights the potential of (13)C solid-state NMR to detect and quantify various hydrogen bonded species in amorphous solid dispersions as well as to serve as an experimental validation of MD simulations.

  19. Protective effects of polyvinylpyrrolidone-wrapped fullerene against intermittent ultraviolet-A irradiation-induced cell injury in HaCaT cells.

    PubMed

    Saitoh, Yasukazu; Ohta, Hiroaki; Hyodo, Sayuri

    2016-10-01

    To identify compounds that suppress UV irradiation-induced oxidative stress in the skin, various types of antioxidants have been studied. Polyvinylpyrrolidone-entrapped fullerene (C60/PVP) is known as a powerful antioxidant that exerts a cytoprotective effect against UV irradiation-induced cell injury in human skin cells and skin models. However, the effects of the alternate attractive C60/PVP feature, persistent antioxidant ability, on cytoprotection have rarely been ascertained. In this study we therefore investigated the efficacies of C60/PVP using an intermittently repeated UVA irradiation model wherein human keratinocytes were repeatedly exposed to UVA five times every 1h and compared the cytoprotective effects with those provided by ascorbic acid-2-O-phosphate-disodium salt (APS) and α-tocopherol (α-Toc). Our results demonstrated that C60/PVP yielded prominent cytoprotective effects against intermittently repeated UVA irradiation-induced injuries in a dose-dependent manner and suppressed intracellular superoxide anion radical (O2(-)) generation both during and after the repeated UVA irradiation. Additionally, C60/PVP also repressed the intermittent UVA irradiation-induced apoptosis via suppression of chromatin condensation and caspase-3/7 activation. Furthermore, the observed cytoprotective effects were superior to the effects of the typical antioxidants APS and α-Toc. These data suggest that C60/PVP might function as a potent cosmetic antioxidant against the effects of repeated and prolonged UVA irradiation through its persistent antioxidative property.

  20. Synthesis and self-assembly of temperature-responsive copolymers based on N-vinylpyrrolidone and triethylene glycol methacrylate

    PubMed Central

    Jumeaux, Coline; Chapman, Robert; Chandrawati, Rona; Stevens, Molly M.

    2017-01-01

    Polyvinylpyrrolidone (PVP) is a biocompatible, water-soluble polymer with unique physicochemical properties and attractive biological features that has found widespread use in several industries. Owing to advances in controlled polymerisation techniques, PVP can be easily synthesised with robust control over its architecture. However, the synthesis of PVP copolymers, which can allow tailoring of its properties and expand the scope of this polymeric material, is challenging and rarely reported. Here, we demonstrate the synthesis of well-defined, temperature-responsive polyvinylpyrrolidone-co-poly(triethylene glycol methacrylate) (PVP-co-pTEGMA) block copolymers via successive Reversible Addition-Fragmentation chain Transfer (RAFT) and Activators ReGenerated by Electron Transfer Atom Transfer Radical Polymerisation (ARGET-ATRP) techniques. We show that PVP-co-pTEGMA block copolymers display temperature-responsive behaviour and self-assemble above their cloud point temperature (Tcp) to form spherical nanostructures of 100-200 nm in diameter. Finally, we demonstrate stabilisation of these assemblies below their Tcp by cross-linking through the PVP block. PMID:28458725

  1. [Evaluation of greenlight photoselective vaporization of prostate and plasmakinetic resection of prostate for the treatment of eldly benign prostatic hyperplasia men with high surgical risk: a prospective randomised control trial].

    PubMed

    Liu, Ling; Lei, Jun-Hao; He, Qi-Ying; Li, Xiang; Yang, Lu

    2014-07-01

    To compare the clinical effects and safety between greenlight photoselective vaporization of prostate (PVP) and plasmakinetic resection of prostate (PRP) in eldly benign prostatic hyperplasia (BPH) men with high surgical risk. METHODS; Fifty three eldly BPH patients, who had the indication of surgical treatment but complicated with at least one internal disease, were randomly divided into PVP group and PRP group. The clinical data of all the patients were collected and compared between the two groups, including pre-operative and post-operative international prostate symptom score (IPSS), postvoid residual urine (PVR), urine flow rate (Qmax), quality of life (QOL) as well as prostate volume (PV), operational time, operative bleeding volume, postoperative recovery, peri-operative complications. The complete follow-up data of 44 patients were achieved: 21 of PVP, 23 of PRP. There were significant differences between two groups in operative bleeding, bladder irrigation time, indwelling catheter time and hospital stay (P < 0.002). The peri-operative bleeding was lower in PVP group, while the bladder irrigation time, indwelling catheter time and hospital stay were shorter in PVP group. The operation time showed no difference (P = 0.12). No significant differences were found 3 months postoperatively between two groups in all the data associated with urination (IPSS, Qmax, PVR, QOL), P > 0.05. Complications (urethrostenosis, retrograde ejaculationwere acceptable in both groups. For surgical treatment of eldly men with high surgical risk, both PVP and PRP are safe and effective with the internal disease being sufficient control.

  2. Frozen-thawed spermatozoa from oligozoospermic ejaculates are susceptible to in situ DNA fragmentation in polyvinylpyrrolidone-based sperm-immobilization medium.

    PubMed

    Salian, Sujit Raj; Kalthur, Guruprasad; Uppangala, Shubhashree; Kumar, Pratap; Adiga, Satish Kumar

    2012-08-01

    To elucidate the effect of sperm immobilization media that are and are not based on polyvinylpyrrolidone (PVP) on the DNA integrity of fresh and frozen-thawed spermatozoa during standard intracytoplasmic sperm injection (ICSI) conditions. Experimental prospective study. Embryology research laboratory. Forty-six ejaculates from normozoospermic and oligozoospermic men. Assessment of sperm DNA fragmentation by single-cell gel electrophoresis assay. DNA integrity of fresh and frozen-thawed spermatozoa from normozoospermic and oligozoospermic ejaculates exposed to PVP-based and non-PVP-based media. Exposure of fresh and frozen thawed spermatozoa from normozoospermic and oligozoospermic ejaculates to PVP-based medium in an ICSI dish for 30 minutes statistically significantly increased the DNA fragmentation. In contrast, the extent of DNA fragmentation in non-PVP-based medium did not statistically significantly differ from control. A PVP-based medium can induce a statistically significant amount of sperm DNA fragmentation in an ICSI dish, and frozen-thawed sperm from oligozoospermic ejaculates are more susceptible to in situ DNA fragmentation. Copyright © 2012 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.

  3. Synthesis of palladium nanoparticles by sonochemical reduction of palladium(II) nitrate in aqueous solution.

    PubMed

    Nemamcha, Abderrafik; Rehspringer, Jean-Luc; Khatmi, Djameledine

    2006-01-12

    The sonochemical synthesis of stable palladium nanoparticles has been achieved by ultrasonic irradiation of palladium(II) nitrate solution. The starting solutions were prepared by the addition of different concentrations of palladium(II) nitrate in ethylene glycol and poly(vinylpyrrolidone) (PVP). The resulting mixtures were irradiated with ultrasonic 50 kHz waves in a glass vessel for 180 min. The UV-visible absorption spectroscopy and pH measurements revealed that the reduction of Pd(II) to metallic Pd has been successfully achieved and that the obtained suspensions have a long shelf life. The protective effect of PVP was studied using Fourier transform infrared (FT-IR) spectroscopy. It has been found that, in the presence of ethylene glycol, the stabilization of the nanoparticles results from the adsorption of the PVP chain on the palladium particle surface via the coordination of the PVP carbonyl group to the palladium atoms. The effect of the initial Pd(II) concentration on the Pd nanoparticle morphology has been investigated by transmission electron microscopy. It has been shown that the increase of the Pd(II)/PVP molar ratio from 0.13 x 10(-3) to 0.53 x 10(-3) decreases the number of palladium nanoparticles with a slight increase in particle size. For the highest Pd(II)/PVP value, 0.53 x 10(-3), the reduction reaction leads to the unexpected smallest nanoparticles in the form of aggregates.

  4. Removal of some textile dyes from aqueous solutions by poly( N-vinyl-2-pyrrolidone) and poly( N-vinyl-2-pyrrolidone)/K 2S 2O 8 hydrogels

    NASA Astrophysics Data System (ADS)

    Can, Hatice Kaplan; Kirci, Betül; Kavlak, Serap; Güner, Ali

    2003-12-01

    Poly( N-vinyl-2-pyrrolidone)/water and poly( N-vinyl-2-pyrrolidone)/K 2S 2O 8/water systems are hydrogels prepared by irradiation with γ-rays at ambient temperature. Both hydrogel systems were employed for diffusion and swelling experiments in various textile dyes aqueous solutions (textile dyes such as Cibacron Blue (CB) F3GA, Methyl Orange (MO), Congo Red (CR)). For these hydrogel systems, swelling studies indicated that swelling percentages increased in the following order: MO>CB F3GA>CR at fixed dose 96 kGy. Because of this reason MO dye solution has been chosen and all swelling properties are investigated for 26, 64, 96 and 124 kGy. The swelling capabilities of PVP and PVP/K 2S 2O 8 hydrogels in MO dye solution vary in the range of 400-1500%. The diffusion of dye solutions PVP and PVP/K 2S 2O 8 hydrogels was assumed to be Fickian character. The swelling behavior of PVP and PVP/K 2S 2O 8 hydrogels exhibits second-order kinetic in all dye solutions. Diffusion coefficient, initial swelling rate, swelling rate constant, maximum swelling and equilibrium water/dye content were found for all gel systems in dye solutions.

  5. Polymer blends used to prepare nifedipine loaded hollow microspheres for a floating-type oral drug delivery system: in vitro evaluation.

    PubMed

    Zhao, Ling; Wei, Yu-meng; Yu, Yu; Zheng, Wen-wu

    2010-03-01

    The aim of this study was to investigate whether hollow microspheres prepared from polymer blends of polyvinyl pyrrolidone (PVP) and ethyl cellulose (EC) could improve the vitro release behavior of the poorly water-soluble drug nifedipine. Hollow microspheres containing nifedipine were prepared by a solvent diffusion-evaporation method using various ratios of PVP and EC codissolved with drug in ethanol/ether (5:1, v/v). The hollow microspheres could float in release medium for more than 24 h, and floating capacities were not be influenced by mixing PVP. In vitro release profiles of hollow microspheres prepared using EC along showed an initial burst release to some extent, and the cumulative release percentage was less than 55% after 24 h. But, not only the slope but also the shape of the release curves was affected by using mixture of PVP and EC. What's more important, when the ratio (PVP/EC) increased to 1.5:8.5, the cumulative release percentage could be increased to 95.8%. Furthermore, the release rate of microspheres showed a zero order approximate dynamic model and could be expressed by the following equation: Q=3.78t+8.52 (r=0.990). Consequently, hollow microspheres prepared using polymer blends of PVP and EC (1.5:8.5, w/w) could be suitable for floating-type controlled-release delivery systems for the oral administration of nifedipine.

  6. Investigation of Rapid Low-Power Microwave-Induction Heating Scheme on the Cross-Linking Process of the Poly(4-vinylphenol) for the Gate Insulator of Pentacene-Based Thin-Film Transistors.

    PubMed

    Fan, Ching-Lin; Shang, Ming-Chi; Wang, Shea-Jue; Hsia, Mao-Yuan; Lee, Win-Der; Huang, Bohr-Ran

    2017-07-03

    In this study, a proposed Microwave-Induction Heating (MIH) scheme has been systematically studied to acquire suitable MIH parameters including chamber pressure, microwave power and heating time. The proposed MIH means that the thin indium tin oxide (ITO) metal below the Poly(4-vinylphenol) (PVP) film is heated rapidly by microwave irradiation and the heated ITO metal gate can heat the PVP gate insulator, resulting in PVP cross-linking. It is found that the attenuation of the microwave energy decreases with the decreasing chamber pressure. The optimal conditions are a power of 50 W, a heating time of 5 min, and a chamber pressure of 20 mTorr. When suitable MIH parameters were used, the effect of PVP cross-linking and the device performance were similar to those obtained using traditional oven heating, even though the cross-linking time was significantly decreased from 1 h to 5 min. Besides the gate leakage current, the interface trap state density (Nit) was also calculated to describe the interface status between the gate insulator and the active layer. The lowest interface trap state density can be found in the device with the PVP gate insulator cross-linked by using the optimal MIH condition. Therefore, it is believed that the MIH scheme is a good candidate to cross-link the PVP gate insulator for organic thin-film transistor applications as a result of its features of rapid heating (5 min) and low-power microwave-irradiation (50 W).

  7. Investigation of Rapid Low-Power Microwave-Induction Heating Scheme on the Cross-Linking Process of the Poly(4-vinylphenol) for the Gate Insulator of Pentacene-Based Thin-Film Transistors

    PubMed Central

    Fan, Ching-Lin; Shang, Ming-Chi; Wang, Shea-Jue; Hsia, Mao-Yuan; Lee, Win-Der; Huang, Bohr-Ran

    2017-01-01

    In this study, a proposed Microwave-Induction Heating (MIH) scheme has been systematically studied to acquire suitable MIH parameters including chamber pressure, microwave power and heating time. The proposed MIH means that the thin indium tin oxide (ITO) metal below the Poly(4-vinylphenol) (PVP) film is heated rapidly by microwave irradiation and the heated ITO metal gate can heat the PVP gate insulator, resulting in PVP cross-linking. It is found that the attenuation of the microwave energy decreases with the decreasing chamber pressure. The optimal conditions are a power of 50 W, a heating time of 5 min, and a chamber pressure of 20 mTorr. When suitable MIH parameters were used, the effect of PVP cross-linking and the device performance were similar to those obtained using traditional oven heating, even though the cross-linking time was significantly decreased from 1 h to 5 min. Besides the gate leakage current, the interface trap state density (Nit) was also calculated to describe the interface status between the gate insulator and the active layer. The lowest interface trap state density can be found in the device with the PVP gate insulator cross-linked by using the optimal MIH condition. Therefore, it is believed that the MIH scheme is a good candidate to cross-link the PVP gate insulator for organic thin-film transistor applications as a result of its features of rapid heating (5 min) and low-power microwave-irradiation (50 W). PMID:28773101

  8. 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.

  9. 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.

  10. 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.

  11. A Fatal Case of Pentedrone and α-Pyrrolidinovalerophenone Poisoning.

    PubMed

    Sykutera, Marzena; Cychowska, Magdalena; Bloch-Boguslawska, Elżbieta

    2015-05-01

    We report a fatal case of combined α-pyrrolidinovalerophenone (α-PVP) and 2-(methylamino)-1-phenylpentan-1-one (pentedrone) poisoning. A 28-year-old man was taken to hospital in asystole. Despite resuscitation efforts over 30 min, he died. The forensic autopsy showed pulmonary edema and moderately advanced atherosclerotic lesions of the arteries. Microscopic observation revealed chronic changes in the heart. Confirmation of the presence of pentedrone, α-PVP, and its metabolite 1-phenyl-2-(pyrrolidin-1-yl)pentan-1-ol (OH-α-PVP) in tissues and fluids were achieved using gas chromatography-mass spectrometry analysis after liquid-liquid extraction. A quantitative validated liquid chromatography-mass spectrometry method was used to determine the concentrations of the above designer drugs in postmortem samples. Pentedrone, α-PVP, and OH-α-PVP concentrations were 8,794, 901 and 185 ng/mL in whole blood, respectively; 100,044, 2,610 and 2,264 ng/g in the liver, respectively; 22,102, 462 and 294 ng/g in the kidney, respectively; 13,248, 120 and 91 ng/g in the brain, respectively and 500,534, 4,190 and 47 ng/g in the stomach contents, respectively. This is the first known reported death attributed to the combined use of α-PVP and pentedrone. Additionally, this article is the first to report the distribution of pentedrone in postmortem human samples.

  12. 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.

  13. 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.

  14. 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

  15. Fractional laser-assisted drug delivery: Active filling of laser channels with pressure and vacuum alteration.

    PubMed

    Erlendsson, Andrés M; Doukas, Apostolos G; Farinelli, William A; Bhayana, Brijesh; Anderson, R Rox; Haedersdal, Merete

    2016-02-01

    Ablative fractional laser (AFXL) is rapidly evolving as one of the foremost techniques for cutaneous drug delivery. While AFXL has effectively improved topical drug-induced clearance rates of actinic keratosis, treatment of basal cell carcinomas (BCCs) has been challenging, potentially due to insufficient drug uptake in deeper skin layers. This study sought to investigate a standardized method to actively fill laser-generated channels by altering pressure, vacuum, and pressure (PVP), enquiring its effect on (i) relative filling of individual laser channels; (ii) cutaneous deposition and delivery kinetics; (iii) biodistribution and diffusion pattern, estimated by mathematical simulation. Franz diffusion chambers (FCs) were used to evaluate the PVP-technique, comparing passive (AFXL) and active (AFXL + PVP) channel filling. A fractional CO2-laser generated superficial (225 µm;17.5 mJ/channel) and deep (1200 µm; 130.5 mJ/channel) channels, and PVP was delivered as a 3-minutes cycle of 1 minute pressure (+1.0 atm), 1 minute vacuum (-1.0 atm), and 1 minute pressure (+1.0 atm). Filling of laser channels was visualized with a colored biomarker liquid (n = 12 FCs, n = 588 channels). Nuclear magnetic resonance quantified intracutaneous deposition of topically applied polyethylene glycol (PEG400) over time (10 minutes, 1 hour, and 4 hours), investigated with (n = 36 FCs) and without (n = 30 FCs) PVP-filling. Two-dimensional mathematical simulation was used to simulate intradermal biodistribution and diffusion at a depth of 1,000 µm. Active filling with application of PVP increased the number of filled laser channels. At a depth of 1,000 µm, filling increased from 44% (AFXL) to 94% with one PVP cycle (AFXL + PVP; P < 0.01). Active filling greatly enhanced intracutaneous deposition of PEG400, resulting in a rapid delivery six-folding uptake at 10 minutes (AFXL 54 µg/ml vs. AFXL + PVP 303 µg/ml, P < 0.01). AFXL alone generated an inhomogeneous uptake of PEG400

  16. 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.

  17. Hyperexponential and nonmonotonic retention of polyvinylpyrrolidone-coated silver nanoparticles in an Ultisol.

    PubMed

    Wang, Dengjun; Ge, Liqiang; He, Jianzhou; Zhang, Wei; Jaisi, Deb P; Zhou, Dongmei

    2014-08-01

    The increasing application of engineered nanoparticles (ENPs) has heightened the concern that these ENPs would eventually be released to the environment and may enter into life cycle of living beings. In this regard, it is essential to understand how these ENPs transport and retain in natural soils because they are considered to be a major repository for ENPs. Herein, transport and retention of polyvinylpyrrolidone (PVP)-coated silver nanoparticles (PVP-AgNPs) were investigated over a wide range of physicochemical factors in water-saturated columns packed with an Ultisol rich in clay-size particles. Higher mobility of PVP-AgNPs occurred at larger soil grain size, lower solution ionic strength and divalent cation concentration, higher flow rate, and greater PVP concentrations. Most breakthrough curves (BTCs) for PVP-AgNPs exhibited significant amounts of retardation in the soil due to its large surface area and quantity of retention sites. In contrast to colloid filtration theory, the shapes of retention profiles (RPs) for PVP-AgNPs were either hyperexponential or nonmonotonic (a peak in particle retention down-gradient from the column inlet). The BTCs and hyperexponential RPs were successfully described using a 1-species model that considered time- and depth-dependent retention. Conversely, a 2-species model that included reversibility of retained PVP-AgNPs had to be employed to better simulate the BTCs and nonmonotonic RPs. As the retained concentration of species 1 approached the maximum solid-phase concentration, a second mobile species (species 2, i.e., the same PVP-AgNPs that are reversibly retained) was released that could be retained at a different rate than species 1 and thus yielded the nonmonotonic RPs. Some retained PVP-AgNPs were likely to irreversibly deposit in the primary minimum associated with microscopic chemical heterogeneity (favorable sites). Transmission electron microscopy and energy-dispersive X-ray spectroscopy analysis suggested that these

  18. A new Plasmodium vivax reference sequence with improved assembly of the subtelomeres reveals an abundance of pir genes

    PubMed Central

    2016-01-01

    Plasmodium vivax is now the predominant cause of malaria in the Asia-Pacific, South America and Horn of Africa. Laboratory studies of this species are constrained by the inability to maintain the parasite in continuous ex vivo culture, but genomic approaches provide an alternative and complementary avenue to investigate the parasite’s biology and epidemiology. To date, molecular studies of P. vivax have relied on the Salvador-I reference genome sequence, derived from a monkey-adapted strain from South America. However, the Salvador-I reference remains highly fragmented with over 2500 unassembled scaffolds.  Using high-depth Illumina sequence data, we assembled and annotated a new reference sequence, PvP01, sourced directly from a patient from Papua Indonesia. Draft assemblies of isolates from China (PvC01) and Thailand (PvT01) were also prepared for comparative purposes. The quality of the PvP01 assembly is improved greatly over Salvador-I, with fragmentation reduced to 226 scaffolds. Detailed manual curation has ensured highly comprehensive annotation, with functions attributed to 58% core genes in PvP01 versus 38% in Salvador-I. The assemblies of PvP01, PvC01 and PvT01 are larger than that of Salvador-I (28-30 versus 27 Mb), owing to improved assembly of the subtelomeres.  An extensive repertoire of over 1200 Plasmodium interspersed repeat (pir) genes were identified in PvP01 compared to 346 in Salvador-I, suggesting a vital role in parasite survival or development. The manually curated PvP01 reference and PvC01 and PvT01 draft assemblies are important new resources to study vivax malaria. PvP01 is maintained at GeneDB and ongoing curation will ensure continual improvements in assembly and annotation quality. PMID:28008421

  19. Fabrication of porous chitosan-polyvinyl pyrrolidone scaffolds from a quaternary system via phase separation.

    PubMed

    Lim, Jin Ik; Im, Heejung; Lee, Woo-Kul

    2015-01-01

    Three-dimensional porous chitosan-polyvinyl pyrrolidone (PVP) scaffolds were fabricated for tissue engineering applications via liquid-liquid or liquid-solid phase separation. A mixture of an acidic aqueous solution with butanol as a non-solvent and a chitosan-PVP quaternary system were freeze-dried. We then studied the homogenous open pore structure and the minute pore distribution in order to improve the mass transfer and cell seeding efficiency while also obtaining the optimal ratio of PVP to provide high interconnectivity and to improve the open-pore structure. The properties of the porous chitosan-PVP scaffolds - including the microstructure, chemical release, water absorption properties, and cell proliferation tests were studied - and the results were compared against those obtained from conventional scaffolds. chitosan-PVP scaffolds with a porosity of over 70% were obtained, and the pore morphology on the surface and within the porous scaffolds showed the presence of homogenous open pores with excellent interconnectivity. As the PVP content increased, main pores (50-100 μm) and minute pores (4-10 μm) could be clearly observed. Also, the porous scaffold showed an improved efficiency for cell adhesion after the cells were cultured for 4 h. After 72 h, the cultured cells presented an increase in the cell proliferation and on the porous scaffolds. These results strongly suggest that the porous chitosan-PVP scaffolds can be widely used in tissue engineering, including for biopatches and artificial skin applications.

  20. 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

  1. Preparation of mesoporous titanium dioxide anode by a film- and pore-forming agent for the dye-sensitized solar cell

    SciTech Connect

    Hou, Wenjing; Xiao, Yaoming Han, Gaoyi Zhou, Haihan; Chang, Yunzhen; Zhang, Ying

    2016-04-15

    Highlights: • PVP is used as a film- and pore-forming agent to prepare the mesoporous TiO{sub 2} anode. • The TiO{sub 2} anode supplies high surface area for the dye adsorption. • The DSSC efficiency is strongly dependent on the pore properties of the TiO{sub 2} anode. • The DSSC efficiency with the TiO{sub 2} anode prepared by 20 wt% PVP reaches 8.39%. - Abstract: A novel mean of generating mesoporous titanium dioxide (TiO{sub 2}) anodes by employing polyvinylpyrrolidone (PVP) as the film- and pore-forming agent are proposed for dye-sensitized solar cells (DSSCs). The influences on the morphology and photovoltaic performances of the TiO{sub 2} anodes are investigated by adjusting the PVP content in synthesizing the mesoporous TiO{sub 2} anodes. The photovoltaic conversion efficiency of the DSSC is found to be strongly dependent on the pore properties of the TiO{sub 2} anode. After the sintering process, the removal of the PVP leaves porously interconnected channel structures inside the TiO{sub 2} anode, supplying enhanced specific surface area for the dye adsorption as well as the efficient electron transmission. As a result, the TiO{sub 2} anode prepared by 20 wt% PVP presents the highest performances, based on which the DSSC achieves the highest conversion efficiency of 8.39%, approximately increased by 56.53% than that of the DSSC fabricated without PVP (5.36%).

  2. Comparative toxicity of silver nanoparticles on oxidative stress and DNA damage in the nematode, Caenorhabditis elegans.

    PubMed

    Ahn, Jeong-Min; Eom, Hyun-Jeong; Yang, Xinyu; Meyer, Joel N; Choi, Jinhee

    2014-08-01

    This study examined the effects of polyvinylpyrrolidone (PVP) surface coating and size on the organismal and molecular toxicity of silver nanoparticles (AgNPs) on the nematode, Caenorhabditis elegans. The toxicity of bare AgNPs and 8 and 38 nm PVP-coated AgNPs (PVP8-AgNPs, PVP38-AgNPs) were compared. The toxicity of AgNO3 was also tested because ion dissolution and particle-specific effects are often important characteristics determining Ag nanotoxicity. Comparative toxicity across AgNO3 and the three different types of AgNPs was first evaluated using a C. elegans mortality test by a direct comparison of the LC50 values. Subsequently, mutant screening followed by oxidative stress, mitochondrial toxicity and DNA damage assays were carried out at equitoxic (LC10 and LC50) concentrations to further assess the toxicity mechanism of AgNO3 and AgNPs. AgNO3 and bare AgNPs had similar toxicities, whereas PVP coating reduced the toxicity of the AgNPs significantly. Of the PVP-AgNPs, the smaller NPs were more toxic. Different groups of mutants responded differently to AgNO3 and AgNPs, which indicates that their toxicity mechanism might be different. AgNO3 and bare AgNPs induced mitochondrial membrane damage. None of the silver materials tested caused detectable polymerase-inhibiting DNA lesions in either the nucleus or mitochondria as measured by a quantitative PCR assay, but AgNO3, bare AgNPs and PVP8-AgNPs induced oxidative DNA damage. These results show that coatings on the AgNPs surface and the particle size make a clear contribution to the toxicity of the AgNPs, and oxidative stress-related mitochondrial and DNA damage appear to be potential mechanisms of toxicity. Copyright © 2014 Elsevier Ltd. All rights reserved.

  3. Photoselective vaporization of the prostate with GreenLight 120-W laser versus transurethral resection of the prostate for benign prostatic hyperplasia: a systematic review with meta-analysis of randomized controlled trials.

    PubMed

    Zang, Ya-Chen; Deng, Xin-Xi; Yang, Dong-Rong; Xue, Bo-Xin; Xu, Li-Jun; Liu, Xiao-Long; Zhou, Yi-Bin; Shan, Yu-Xi

    2016-02-01

    The aim of this study is to assess the overall efficacy and safety of photoselective vaporization of the prostate (PVP) with GreenLight 120-W laser versus transurethral resection of the prostate (TURP) for treating patients of benign prostate hyperplasia (BPH) with lower urinary tract symptoms (LUTS). We performed a literature search of The Cochrane Library and the electronic databases, including Embase, Medline, and Web of Science. Manual searches were conducted of the conference proceedings, including European Association of Urology and American Urological Association (2007 to 2012). Outcomes reviewed included clinical baseline characteristics, perioperative data, complications, and postoperative functional results, such as postvoid residual (PVR), international prostate symptom score (IPSS), quality of life (QoL), and maximum flow rate (Qmax). Six randomized controlled trials (RCTs) were enrolled. Three hundred and forty-seven patients undergone 120-W PVP, and 350 patients were treated with TURP in the RCTs. There were no significant differences for clinical characteristics in these trials. In perioperative data, catheterization time and length of hospital stay were shorter in the PVP group. However, the operation time was shorter in the TURP group. Capsular perforation, blood transfusion, clot retention, and macroscopic hematuria were markedly less likely in PVP-treated subjects. The other complications between PVP and TURP did not demonstrate a statistic difference. There were no significant differences in QoL, PVR, IPSS, and Qmax in the 1, 3, 6, 12, and 24 months of postoperative follow-up. There was no significant difference at postoperation follow-up of functional outcomes including IPSS, PVR, Qmax, and QoL between the TURP-treated subjects and PVP-treated subjects. Owing to a shorter catheterization time, reduced hospital duration and less complication, PVP could be used as an alternative and a promising minimal invasive surgical procedure for the

  4. Poly(N-vinylpyrrolidone)-block-poly(vinyl acetate) as a drug delivery vehicle for hydrophobic drugs.

    PubMed

    Bailly, Nathalie; Thomas, Mark; Klumperman, Bert

    2012-12-10

    Poly((N-vinylpyrrolidone)-block-poly(vinyl acetate)) (PVP-b-PVAc) block copolymers of varying molecular weight and hydrophobic block lengths were synthesized via controlled radical polymerization and investigated as carriers for the solubilization of highly hydrophobic riminophenazine compounds. These compounds have recently been shown to exhibit a strong activity against a variety of cancer types. PVP-b-PVAc self-assembles into polymer vesicles in aqueous media, and the dialysis method was used to load the water-insoluble drug (clofazimine) into these polymer vesicles. The polymer vesicles were characterized by 1H NMR spectroscopy to confirm vesicle formation and the incorporation of the anticancer drugs into the polymer vesicles. Dynamic light scattering was used to determine the particle size and particle size distribution of the drug-loaded vesicles as well as the stability of the vesicles under physiological conditions. The size of the polymer vesicles did not increase upon loading with clofazimine, and the particle size of 180-200 nm and the narrow particle size distribution were maintained. The morphology of the vesicles was examined by transmission electron microscopy. The polymer vesicles had a relatively high drug loading capacity of 20 wt %. In vitro cytotoxicity studies of PVP-b-PVAc and drug-loaded PVP-b-PVAc were performed against MDA-MB-231 multidrug-resistant breast epithelial cancer cells and MCF12A nontumorigenic breast epithelial cells. In vitro experiments demonstrated that the PVP-b-PVAc drug carrier showed no cytotoxicity, which confirms the biocompatibility of the PVP-b-PVAc drug carrier. The results indicate that the present PVP-b-PVAc block copolymer could be a potential candidate as a drug carrier for hydrophobic drugs.

  5. A surface epitope undergoing high-frequency phase variation is shared by Mycoplasma gallisepticum and Mycoplasma bovis.

    PubMed Central

    Yogev, D; Menaker, D; Strutzberg, K; Levisohn, S; Kirchhoff, H; Hinz, K H; Rosengarten, R

    1994-01-01

    We have recently reported that three distinct size- and phase-variable surface lipoproteins (Vsps) of the bovine pathogen Mycoplasma bovis possess a common epitope recognized by monoclonal antibody 1E5. In the present study, we show that this epitope is also present on a size-variant protein (PvpA) of the avian pathogen Mycoplasma gallisepticum. Application of monoclonal antibody 1E5 in Western immunoblot analysis of Triton X-114 phase-fractionated proteins and in colony immunoblots, as well as in trypsin and carboxypeptidase digestion experiments, has demonstrated that (i) PvpA is an integral membrane protein with a free C terminus, (ii) the shared epitope is surface exposed, and (iii) PvpA is subjected to high-frequency phase variation in expression. By using serum antibodies from M. gallisepticum-infected chickens, we were able to demonstrate the immunogenic nature of PvpA and identify three additional highly immunogenic Triton X-114 phase proteins (p67, p72, and p75) also undergoing high-frequency phase variation spontaneously and independently. Metabolic labeling experiments with [14C]palmitate and [14C]oleate revealed that PvpA, in contrast to p67, p72, and p75, is not lipid modified. Southern blot hybridization with restriction fragments carrying the pvpA gene of M. gallisepticum or the vspA gene of M. bovis against digested genomic DNA of the two Mycoplasma species indicated the absence of genetic relatedness between the pvpA and vspA genes. The apparent complexity of the antigenic variation phenomenon in M. gallisepticum is discussed. Images PMID:7523302

  6. 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.

  7. Cryopreservation of Indian red jungle fowl (Gallus gallus murghi) semen with polyvinylpyrrolidone.

    PubMed

    Rakha, Bushra Allah; Ansari, Muhammad Sajjad; Akhter, Shamim; Zafar, Zartasha; Hussain, Iftikhar; Santiago-Moreno, Julian; Blesbois, Elisabeth

    2017-10-01

    The Indian red jungle fowl is a sub-species of the genus Gallus native to South Asia; facing high risk of extinction in its native habitat. During cryopreservation, permeable cryoprotectants like glycerol are usually employed and we previously showed encouraging results with 20% glycerol. Because bird spermatozoa contain very little intracellular water, the possibility of replacing an internal cryoprotectant by an external one is opened. In the present study, we tested the replacement of internal cryoprotectant glycerol by the external cryoprotectant Polyvinylpyrrolidone (PVP). PVP is a non-permeable cryoprotectant and keeps the sperm in glassy state both in cooling and warming stages without making ice crystallization within the sperm cell. We evaluated the effect of various levels of polyvinylpyrrolidone (PVP) on Indian red jungle fowl semen quality and fertility outcomes. The qualifying semen ejaculates collected from eight mature cocks were pooled, divided into five aliquots, diluted (37 °C) with red fowl semen extender having PVP [0% (control) 4% (w/v), 6% (w/v), 8% (w/v) and 10% (w/v)]. Diluted semen was cryopreserved and stored in liquid nitrogen. The whole experiment was repeated/replicated for five times independently. Sperm motility, plasma membrane integrity, viability and acrosome integrity were recorded highest (P < 0.05) with 6% PVP at post-dilution, cooling, equilibration and freeze-thawing. Higher (P < 0.05) no. of fertile eggs, fertility, no. of hatched chicks, percent hatch and hatchability was recorded with 6% PVP compared to control. It is concluded that 6% PVP maintained better post-taw quality and fertility of Indian red jungle fowl spermatozoa than glycerol and can be used in routine practice avoiding the contraceptive effects of glycerol. Copyright © 2017 Elsevier Inc. All rights reserved.

  8. Comparison of two generalized transfer functions for measuring central systolic blood pressure by an oscillometric blood pressure monitor.

    PubMed

    Shih, Y-T; Cheng, H-M; Sung, S-H; Hu, W-C; Chen, C-H

    2013-03-01

    Central aortic systolic blood pressure (SBP-C) can be estimated from a cuff oscillometric waveform derived during the pulse volume plethysmography (PVP) by applying a device-specific aortic pressure-to-PVP waveform-generalized transfer function (A2P(GTF)). The present study compared the performance of an aortic-to-brachial pressure waveforms generalized transfer function (A2B(GTF)), which is independent of any PVP devices, with an A2P(GTF). Generalized transfer function of aortic-to-brachial (A2B(GTF)) and aortic-to-PVP (A2P(GTF)) were generated from the simultaneously obtained central aortic and brachial pressure waveforms recorded by a high-fidelity dual pressure sensor catheter, and the PVP waveform recorded by a customized noninvasive blood pressure monitor during cardiac catheterization in 40 patients, and were then applied in another 100 patients with simultaneously recorded invasive aortic pressure and noninvasively calibrated (using cuff SBP and diastolic blood pressures) PVP waveforms. The mean difference±s.d. between the noninvasively estimated and invasively recorded SBP-C was -2.1±7.7 mm Hg for A2B(GTF), which was not greater than that of -3.0±7.7 mm Hg for A2P(GTF) (P<0.01). In conclusion, SBP-C can be measured reliably using a noninvasive blood pressure monitor by applying either an A2P(GTF) or A2B(GTF) to a noninvasively calibrated PVP waveform. The performance of an A2B(GTF) is not inferior to that of an A2P(GTF).

  9. 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.

  10. 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

  11. A rapid approach for measuring silver nanoparticle concentration and dissolution in seawater by UV-Vis.

    PubMed

    Sikder, Mithun; Lead, Jamie R; Chandler, G Thomas; Baalousha, Mohammed

    2017-04-12

    Detection and quantification of engineered nanoparticles (NPs) in environmental systems is challenging and requires sophisticated analytical equipment. Furthermore, dissolution is an important environmental transformation process for silver nanoparticles (AgNPs) which affects the size, speciation and concentration of AgNPs in natural water systems. Herein, we present a simple approach for the detection, quantification and measurement of dissolution of PVP-coated AgNPs (PVP-AgNPs) based on monitoring their optical properties (extinction spectra) using UV-vis spectroscopy. The dependence of PVP-AgNPs extinction coefficient (ɛ) and maximum absorbance wavelength (λmax) on NP size was experimentally determined. The concentration, size, and extinction spectra of PVP-AgNPs were characterized during dissolution in 30ppt synthetic seawater. AgNPs concentration was determined as the difference between the total and dissolved Ag concentrations measured by inductively coupled plasma-mass spectroscopy (ICP-MS); extinction spectra of PVP-AgNPs were monitored by UV-vis; and size evolution was monitored by atomic force microscopy (AFM) over a period of 96h. Empirical equations for the dependence of maximum absorbance wavelength (λmax) and extinction coefficient (ɛ) on NP size were derived. These empirical formulas were then used to calculate the size and concentration of PVP-AgNPs, and dissolved Ag concentration released from PVP-AgNPs in synthetic seawater at variable particle concentrations (i.e. 25-1500μgL(-1)) and in natural seawater at particle concentration of 100μgL(-1). These results suggest that UV-vis can be used as an easy and quick approach for detection and quantification (size and concentration) of sterically stabilized PVP-AgNPs from their extinction spectra. This approach can also be used to monitor the release of Ag from PVP-AgNPs and the concurrent NP size change. Finally, in seawater, AgNPs dissolve faster and to a higher extent with the decrease in NP

  12. Photoselective vaporization of the prostate with GreenLight 120-W laser compared with monopolar transurethral resection of the prostate: a multicenter randomized controlled trial.

    PubMed

    Lukacs, Bertrand; Loeffler, Joyce; Bruyère, Franck; Blanchet, Pascal; Gelet, Albert; Coloby, Patrick; De la Taille, Alexandre; Lemaire, Philippe; Baron, Jean-Christophe; Cornu, Jean-Nicolas; Aout, Mounir; Rousseau, Helene; Vicaut, Eric

    2012-06-01

    Evidence supporting the widespread use of GreenLight High Performance System (HPS) 120-W photoselective vaporization of the prostate (PVP) is lacking. To assess the noninferiority of PVP compared with transurethral resection of the prostate (TURP) on urinary symptoms and the superiority of PVP over TURP on length of hospital stay. A multicenter randomized controlled trial was conducted. Patients underwent monopolar TURP or PVP with the GreenLight HPS 120-W laser. International Prostate Symptom Score (IPSS), Euro-QOL questionnaire, uroflowmetry, Danish Prostate Symptom Score Sexual Function Questionnaire, sexual satisfaction, and adverse events were collected at 1, 3, 6, and 12 mo. The two groups were compared using the 95% confidence interval (CI) of median difference for testing noninferiority of the IPSS at 12 mo and the student t test for testing the difference in length of hospital stay. A total of 139 patients (70 vs 69 men in each group) were randomized. Median IPSS scores at 12-mo follow-up were 5 (interquartile range [IQR]: 3-8) for TURP versus 6 (IQR: 3-9) for PVP, and the 95% CI of the difference of the median was equal to -2 to 3. Because the upper limit of the 95% CI was >2 (the noninferiority margin), the hypothesis of noninferiority could not be considered demonstrated. Median length of stay was significantly shorter in the PVP group than in the TURP group, with a median of 1 (IQR: 1-2) versus