Groundwater sampling from shallow boreholes (PP and PR) and groundwater observation tubes (PVP) at Olkiluoto in 2004

Energy Technology Data Exchange (ETDEWEB)

Hirvonen, H. [Teollisuuden Voima Oyj, Eurajoki (Finland)

2005-11-15

Groundwater sampling from the shallow boreholes and groundwater observation tubes was performed in summer 2004 (PP2, PP3, PP7, PP8, PRl, PVPl, PVP3A, PVP3B, PVP4A and PVP4B) and in autumn 2004 (PP2, PP3, PP5, PP7, PP8, PP9, PP36, PP37, PP39, PR1, PR2, PVP1, PVP3A, PVP3B, PVP4A, PVP8A, PVP9A, PVP9B, PVP10B, PVP11, PVP12, PVP13, PVP14 and PVP20). The results from previous samplings have been used in the hydrogeochemical baseline characterization at Olkiluoto and some of the latest results have also been part of the ONKALO monitoring program. This study contains data on preliminary pumping of the sampling points and pumping for groundwater sampling and chemical analyses in the laboratory. This study also includes comparison with analytical results obtained between 1995-2004. The total dissolved solids (TDS) of groundwater samples were mainly below 1000 mg/L. According to Davis's TDS classification, these waters were fresh waters. The only exception was the water sample from shallow borehole PP7 (1400mg/L and 1450mg/L), which was brackish. Several different groundwater types were observed, but the most common water type was Ca-HCO{sub 3} (five samples). Analytical results from 1995-2003 were compared. During 2001-2003 in groundwater samples from sampling points PVP1, PVP9A and PP7 all measured main parameters changed considerably, but from summer 2003 to autumn 2004 the greatest alterations occurred in PR2, PVP1, PVP3A and PVP3B waters. These changes can be seen in almost all parameters. For other samples only minor changes in results were observed during the reference period. (orig.)

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

Science.gov (United States)

Byrska, Bogumiła; Stanaszek, Roman; Zuba, Dariusz

2017-08-01

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. Copyright © 2016 John Wiley & Sons, Ltd.

Dielectric and electrical study of PPy doped PVA-PVP films

Science.gov (United States)

Jha, Sushma; Tripathi, Deepti

2018-05-01

Dielectric parameters of free standing films of pure PVA (PolyvinylAlcohol) and PVA with varying concentrations of PVP(Polyvinylpyrrolidone) and Polypyrrole were prepared and studied in low frequency range (100Hz - 2MHz). The results show that dielectric constant, loss tangent and conductivity increase sharply on increasing the concentration of PVP above 50wt% in polymer matrix. PVA-PVP film with low concentration of PPy showed improvement in the values of complex permittivity, loss tangent and ac conductivity within the experimental frequency range. This eco - friendly polymeric material will be studied for its probable application for RFI/EMI shielding, biosensors, capacitors & insulation purposes.

Study of induced cross-linking by ionizing radiation of polyvinylpyrrolidone (PVP)/carboxymethylcellulose (CMC)

International Nuclear Information System (INIS)

Alcantara, Mara T.S.; Chirinos, Hugo; Amaral, Renata H.; Rogero, Sizue O.; Lugao, Ademar B.

2005-01-01

The polymeric hydrogels are materials with capacity to absorb great amount of water. They present interesting characteristics for many applications in the industry and as biomaterials. The hydrogel membrane with PVP, poly ethylene glycol and agar, crosslinked and sterilized simultaneously by radiation was introduced in the European market and now it is reaching other regions. In this work the hydrogel studied was synthesized with PVP and CMC and crosslinked by gamma radiation. It was applied factorial planning methodology using the gel fraction as basic parameter. Antagonistic interaction was observed between PVP and CMC. High concentrations of PVP help the crosslinking and the opposite with CMC. On the other hand, for low concentrations of PVP the dose influences considerable the gel fraction what it does not happen for high concentrations. From these results it was made an analysis of response surface allowing the optimization of the concentrations of the variables PVP and CMC. (author)

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

International Nuclear Information System (INIS)

Nho, Y. C.; Park, K. R.

2001-01-01

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

Structural and optical band gap of PEO/PVP polymer blend

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Basappa, M.; Yesappa, L.; Niranjana, M.; Ashokkumar, S. P.; Vandana, M.; Vijeth, H.; Devendrappa, H.

2018-05-01

The PEO/PVP polymers blend film at different wt % of PVP is prepared by solution casting method using methanol as a solvent. The blend was characterized by FT-IR to confirm the blend and the peak observed in the region 1230-980 cm-1 corresponds to C-O-C symmetric and asymmetric stretching. The UV-visible absorption shows red shift from 190 to 220 nm in the ultra violet region is attributed to π→π* transition. The direct and indirect optical band gaps were determined and found decreases from 4.99 to 4.62 eV with increased PVP wt % to 50:50.

Interaction between poly(vinyl pyrrolidone) PVP and fullerene C60 at the interface in PVP-C60 nanofluids–A spectroscopic study

Science.gov (United States)

Behera, M.; Ram, S.

2018-03-01

Fourier transform infrared and Raman bands shows a discernible enhancement in band intensity of C–H stretching, C=O stretching, C–N stretching, C–H2 bending, and C–H2 in-plane bending in PVP molecules in the presence of C60 molecules. Amplification in intensity is ascribed to microscopic interactions results when a donation of nonbonding electron (n) occurs from a “>N–C=O” entity of PVP into a lowest unoccupied molecular orbital of the C60 molecule in PVP-C60 charge transfer (CT) complex. The C=O stretching band intensity (integrated) Vs C60 content plot exhibits a peak near a critical 13.9 μM C60 value owing to percolation effect. Light emission spectra show that even a small addition of 4.63 μM C60 able to suppress the band intensity by ~23% as a result of an energy loss. The integrated band intensity also decreases through a peak near 13.9 μM when plotted against the C60-content. In correlation to the vibration spectra, the maximum effect observed both in light emission and excitation spectra suggests a percolation effect in the CT complex. Exhibition of percolation threshold in C60-PVP donor-acceptor complex will be helpful in optimizing the photovoltaic properties vital for solar cell applications.

Potential applications of radiation formed PVA/PVP hydrogel patches

International Nuclear Information System (INIS)

Zein, Z.; Hill, D.J.T.; Whittaker, A.K.

2003-01-01

It has been shown that radiation induced-polymerization and crosslinking is a very convenient method to produce hydrogels. The process is free of catalyst or initiator, which are mostly toxic, easy to control and allows sterilization simultaneously. In this sense, poly(vinyl alcohol) (PVA)/polyvinylpyrrolidone (PVP) hydrogel patches have been prepared by subjecting the polymer aqueous solutions to γ -irradiation. Under the action of ionizing radiation, the mechanism of hydrogel formation may be simplified into two main stages; formation of free radicals and their intermolecular combination. The five-line ESR spectra found following irradiation of PVP (powder) at 77 K and annealing up to 250 K suggests that free-radicals are mainly localized at tertiary carbon atoms. While for PVA, as the major component of the four-line ESR spectra at 77 K was a triplet and this was the only species observed at 298 K, so most radicals were formed through hydrogen abstraction from tertiary carbon atoms. If radicals localized on different molecular chains combine, new covalent bonds are formed. When a sufficiently high number of crosslinks form, an insoluble network (gel) appears. It was observed that the gel fraction for PVA/PVP hydrogels increased with increasing irradiation dose and it seems that the gel fraction never reaches 100%. This implies that upon irradiation of PVA/PVP aqueous solutions, chain scission also accompanies crosslinking. Based on a toxicity test, it was found that none of this chain scission products produce detectable toxicity. The physico-chemical and mechanical properties of the PVA/PVP hydrogel obtained by irradiation of PVA/PVP (8.0 %wt / 4.8 %wt) solution with a crosslinking dose of 25 kGy were shown to yield properties most suitable for ideal wound covering. Additionally, as the hydrogel has a high water content and a relatively moderate water diffusion coefficient, it offers potential for transdermal drug delivery systems as well as for cosmetic

Slug-tests in PP- and PVP-holes at Olkiluoto in 2006

International Nuclear Information System (INIS)

Keskitalo, K.; Lindgren, S.

2007-11-01

As part of the program for the final disposal of the nuclear fuel waste, Posiva Oy investigates the hydrological conditions at the Olkiluoto island. The hydraulic conductivity in the shallow holes OL-PP5, OL-PP9, OL-PP36, OL-PP39, OL-PVP4A, OL-PVP4B, OL-PVP6A, OL-PVP6B and OL-PVP14 was measured in summer 2006. The length of PP-holes varies between 12 and 15 m, and the test sections (1 m) are located in the bedrock. PVP-tubes have a length up to 10 m, and the test sections (2 m) are located in the overburden. The measurements were done using the slug-test technique. In the slug-test, the hydraulic head in the borehole is abruptly changed either by pouring water into the borehole or by lowering the pressure sensor. The conductivity is interpreted based on the recovery of the water level. This report presents the field measurements and their interpretation. The interpretation has been done using the Hvorslev's method, and for reference, conductivity has also been calculated according to Thiem's equation. According to the results, hydraulic conductivity in PP-holes ranges from 10 -9 m/s to 10 -6 m/s and in PVP-tubes from 10 -8 m/s to 10 -5 m/s. The range is similar as observed in measurements of years 2002, 2004 and 2005. In general the results are consistent with the results obtained in earlier measurements. Some exceptions exist in OL-PP9, where the conductivity is lower than in the 2005 measurements, but still at the same level as in the 2002 measurements. Also, the results agree with hydraulic conductivity interpreted from the pre-pumping done in connection with the groundwater sampling. (orig.)

DeepPVP: phenotype-based prioritization of causative variants using deep learning

KAUST Repository

Boudellioua, Imene; Kulmanov, Maxat; Schofield, Paul N; Gkoutos, Georgios V; Hoehndorf, Robert

2018-01-01

phenotype-based methods that use similar features. DeepPVP is freely available at https://github.com/bio-ontology-research-group/phenomenet-vp Conclusions: DeepPVP further improves on existing variant prioritization methods both in terms of speed as well

XPS and NEXAFS analysis of dimethyl sulfide adsorbed on the Rh(PVP) nanoparticle surface

International Nuclear Information System (INIS)

Niwa, Hironori; Ogawa, Satoshi; Yagi, Shinya; Kutluk, Galif

2010-01-01

We have studied the adsorption reaction of dimethyl sulfide (DMS: (CH 3 ) 2 S) on the surface of Rh(PVP) nanoparticles by using AFM, XPS and NEXAFS techniques. The AFM images show the degree of dispersion of the Rh(PVP) nanoparticles depends on the amount of them. The in-situ XPS results indicate that the dissociation reaction of DMS into atomic S does not depend upon the existence of the Rh(PVP) nanoparticles. The NEXAFS results show that there is a strong chemical bonding between Rh(PVP) nanoparticle and atomic S. The ex-situ XPS results show the atomic S adsorbed on the Rh(PVP) nanoparticles partially desorb by exposing to the air. (author)

Stable and Fast-Response Capacitive Humidity Sensors Based on a ZnO Nanopowder/PVP-RGO Multilayer

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Hui Yang

2017-10-01

Full Text Available In this paper, capacitive-type humidity sensors were prepared by sequentially drop-coating the aqueous suspensions of zinc oxide (ZnO nanopowders and polyvinyl pyrrolidone–reduced graphene oxide (PVP-RGO nanocomposites onto interdigitated electrodes. Significant improvements in both sensitivity and linearity were achieved for the ZnO/PVP-RGO sensors compared with the PVP-RGO/ZnO, PVP-RGO, and ZnO counterparts. Moreover, the produced ZnO/PVP-RGO sensors exhibited rather small hysteresis, fast response-recovery time, and long-term stability. Based on morphological and structural analyses, it can be inferred that the excellent humidity sensing properties of the ZnO/PVP-RGO sensors may be attributed to the high surface-to-volume ratio of the multilayer structure and the supporting roles of the PVP-RGO nanocomposites. The results in this work hence provide adequate guidelines for designing high-performance humidity sensors that make use of the multilayer structure of semiconductor oxide materials and PVP-RGO nanocomposites.

Radiation induced synthesis of colloidal silver nanoparticles stabilized by PVP/chitosan

International Nuclear Information System (INIS)

Dang Van Phu; Nguyen Trieu; Vo Thi Kim Lang; Nguyen Quoc Hien; Bui Duy Du

2008-01-01

Colloidal silver nanoparticle solution (10 mmol) was prepared by gamma 60 Co irradiation using polyvinyl pyrrolidone (PVP), water soluble chitosan (WSC) and mixture of PVP/WSC as stabilizers. Saturated conversion doses (Ag + → Ag 0 ) and maximum absorption wavelengths (λ max ) were determined by UV-vis spectra to be of 28 kGy (405.5 nm), 20 kGy (418.5 nm), 24 kGy (415.0 nm) and 24 kGy (407.0 nm) for PVP 1% (C1), WSC 0.5% (C2), PVP 1%/WSC 0.5% (C3) and PVP 1%/ethanol 1 M (C4), respectively. Results of the conversion doses indicated that WSC and ethanol plays a role in scavenging the OH* and H* arising from radiolysis of water, which reduced the conversion dose from 28 kGy (C1) to 20 kGy (C2). The average size of silver nanoparticles was characterized by Transmission Electron Microscopy (TEM) as 15.96 ± 0.51, 5.55 ± 0.25, 2.92 ± 0.05, and 11.44 ±2.07 nm for C1, C2, C3 and C4, respectively. The obtained result of silver nanoparticle sizes showed that WSC exhibited the effect of reducing silver nanoparticle size in colloids, especially the mixture of PVP/WSC that reduced the size of silver nanoparticle from ∼16 nm (C1) to about 3 nm (C3). The effect of NaNO 3 on stability of colloidal silver nanoparticles has been also investigated. (author)

PEO + PVP blended polymer composite

Indian Academy of Sciences (India)

Blended polymer films of polyethylene oxide + polyvinyl pyrrolidone (PEO + PVP) containing transition metal (TM) ions like Fe3+, Co2+ and Ni2+ have been synthesized by a solution casting method. For these films, structural, thermal, magnetic and optical properties have been studied. X-ray diffraction results reveal the ...

DeepPVP: phenotype-based prioritization of causative variants using deep learning

KAUST Repository

Boudellioua, Imene

2018-05-02

Background: Prioritization of variants in personal genomic data is a major challenge. Recently, computational methods that rely on comparing phenotype similarity have shown to be useful to identify causative variants. In these methods, pathogenicity prediction is combined with a semantic similarity measure to prioritize not only variants that are likely to be dysfunctional but those that are likely involved in the pathogenesis of a patient\\'s phenotype. Results: We have developed DeepPVP, a variant prioritization method that combined automated inference with deep neural networks to identify the likely causative variants in whole exome or whole genome sequence data. We demonstrate that DeepPVP performs significantly better than existing methods, including phenotype-based methods that use similar features. DeepPVP is freely available at https://github.com/bio-ontology-research-group/phenomenet-vp Conclusions: DeepPVP further improves on existing variant prioritization methods both in terms of speed as well as accuracy.

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

Science.gov (United States)

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.

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

Science.gov (United States)

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

2013-06-01

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

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

Energy Technology Data Exchange (ETDEWEB)

Tamgadge, Y. S., E-mail: ystamgadge@gmail.com; Atkare, D. V. [Department of Physics, Mahatma Fule Arts, Commerce & SitaramjiChoudhari Science College, Warud, Dist. Amravati (MS), India-444906 (India); Pahurkar, V. G.; Muley, G. G., E-mail: gajananggm@yahoo.co.in [Department of Physics, SantGadge Baba Amravati University, Amravati (MS), India-444602 (India); Talwatkar, S. S. [Department of Physics, D K Marathe and N G Acharya College, Chembur, Mumbai (MS), India-440071 (India); Sunatkari, A. L. [Department of Physics, Siddharth College of Arts, Science and Commerce, Fort, Mumbai (MS), India-440001 (India)

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.

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

Science.gov (United States)

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 SiO2, Fe2O3 and ZnO normalized to the BET surface area is similar to the sorption densities on smectites. γ-Al2O3, 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 samples.

Comparison Study On Sunlight Or Gamma Radiation Aging Resistance Of Poly (Vinyl Pyrrolidone) Aqueous Solution With PVP Nanogel

International Nuclear Information System (INIS)

Doan Binh; Pham Thu Hong; Nguyen Nguyet Dieu; Nguyen Thanh Duoc

2011-01-01

Comparison study on sunlight or gamma-radiation aging resistance of poly (vinyl pyrrolidone) (PVP) aqueous solution with PVP nanogel at 0.5% was carried out. Sunlight or gamma- radiation aging resistance of PVP aqueous solution and nanogel was evaluated on the basis of their intrinsic viscosity, UV-VIS absorbance, weight averaged molecular weight (M w ). The PVP aqueous solution and nanogel exposed to sunlight in the storage duration of 3 months and to gamma radiation at absorbed doses of 0, 15, 30, 50 kGy were used for this study. Furthermore, the stability of PVP nanogel and of PVP aqueous solution was also studied on the change of their intrinsic viscosity, UV-VIS absorbance, weight averaged molecular weight, particle size distribution and coil size. The experimental results were shown that the aging resistance of PVP nanogel was higher than that of PVP aqueous solution when exposed to gamma radiation or sunlight. (author)

Maintaining Supersaturation of Nimodipine by PVP with or without the Presence of Sodium Lauryl Sulfate and Sodium Taurocholate.

Science.gov (United States)

Pui, Yipshu; Chen, Yuejie; Chen, Huijun; Wang, Shan; Liu, Chengyu; Tonnis, Wouter; Chen, Linc; Serno, Peter; Bracht, Stefan; Qian, Feng

2018-05-30

Amorphous solid dispersion (ASD) is one of the most versatile supersaturating drug delivery systems to improve the dissolution rate and oral bioavailability of poorly water-soluble drugs. PVP based ASD formulation of nimodipine (NMD) has been marketed and effectively used in clinic for nearly 30 years, yet the mechanism by which PVP maintains the supersaturation and subsequently improves the bioavailability of NMD was rarely investigated. In this research, we first studied the molecular interactions between NMD and PVP by solution NMR, using CDCl 3 as the solvent, and the drug-polymer Flory-Huggins interaction parameter. No strong specific interaction between PVP and NMD was detected in the nonaqueous state. However, we observed that aqueous supersaturation of NMD could be significantly maintained by PVP, presumably due to the hydrophobic interactions between the hydrophobic moieties of PVP and NMD in aqueous medium. This hypothesis was supported by dynamic light scattering (DLS) and supersaturation experiments in the presence of different surfactants. DLS revealed the formation of NMD/PVP aggregates when NMD was supersaturated, suggesting the formation of hydrophobic interactions between the drug and polymer. The addition of surfactants, sodium lauryl sulfate (SLS) or sodium taurocholate (NaTC), into PVP maintained that NMD supersaturation demonstrated different effects: SLS could only improve NMD supersaturation with concentration above its critical aggregation concentration (CAC) value while not with lower concentration. Nevertheless, NaTC could prolong NMD supersaturation independent of concentration, with lower concentration outperformed higher concentration. We attribute these observations to PVP-surfactant interactions and the formation of PVP/surfactant complexes. In summary, despite the lack of specific interactions in the nonaqueous state, NMD aqueous supersaturation in the presence of PVP was attained by hydrophobic interactions between the hydrophobic

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

Energy Technology Data Exchange (ETDEWEB)

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

2012-11-15

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

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

International Nuclear Information System (INIS)

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

2012-01-01

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. - Highlights: ► The hydrophilic PVDF-g-PVP powder is used as additive to prepare PVDF/PVDF-g-PVP blend porous membranes. ► The immersion precipitation phase inversion process is adopted to prepare the blend membranes. ► The hydrophilicity of the porous membranes surface is enhanced with increasing the amount of PVDF-g-PVP. ► The pure water flux of the porous membranes depends on the amount of PVDF-g-PVP in the porous membranes. ► Antifouling property of the porous membranes is improved obviously comparing with a pristine PVDF membrane.

PVP-SVM: Sequence-Based Prediction of Phage Virion Proteins Using a Support Vector Machine.

Science.gov (United States)

Manavalan, Balachandran; Shin, Tae H; Lee, Gwang

2018-01-01

Accurately identifying bacteriophage virion proteins from uncharacterized sequences is important to understand interactions between the phage and its host bacteria in order to develop new antibacterial drugs. However, identification of such proteins using experimental techniques is expensive and often time consuming; hence, development of an efficient computational algorithm for the prediction of phage virion proteins (PVPs) prior to in vitro experimentation is needed. Here, we describe a support vector machine (SVM)-based PVP predictor, called PVP-SVM, which was trained with 136 optimal features. A feature selection protocol was employed to identify the optimal features from a large set that included amino acid composition, dipeptide composition, atomic composition, physicochemical properties, and chain-transition-distribution. PVP-SVM achieved an accuracy of 0.870 during leave-one-out cross-validation, which was 6% higher than control SVM predictors trained with all features, indicating the efficiency of the feature selection method. Furthermore, PVP-SVM displayed superior performance compared to the currently available method, PVPred, and two other machine-learning methods developed in this study when objectively evaluated with an independent dataset. For the convenience of the scientific community, a user-friendly and publicly accessible web server has been established at www.thegleelab.org/PVP-SVM/PVP-SVM.html.

PVP-SVM: Sequence-Based Prediction of Phage Virion Proteins Using a Support Vector Machine

Directory of Open Access Journals (Sweden)

Balachandran Manavalan

2018-03-01

Full Text Available Accurately identifying bacteriophage virion proteins from uncharacterized sequences is important to understand interactions between the phage and its host bacteria in order to develop new antibacterial drugs. However, identification of such proteins using experimental techniques is expensive and often time consuming; hence, development of an efficient computational algorithm for the prediction of phage virion proteins (PVPs prior to in vitro experimentation is needed. Here, we describe a support vector machine (SVM-based PVP predictor, called PVP-SVM, which was trained with 136 optimal features. A feature selection protocol was employed to identify the optimal features from a large set that included amino acid composition, dipeptide composition, atomic composition, physicochemical properties, and chain-transition-distribution. PVP-SVM achieved an accuracy of 0.870 during leave-one-out cross-validation, which was 6% higher than control SVM predictors trained with all features, indicating the efficiency of the feature selection method. Furthermore, PVP-SVM displayed superior performance compared to the currently available method, PVPred, and two other machine-learning methods developed in this study when objectively evaluated with an independent dataset. For the convenience of the scientific community, a user-friendly and publicly accessible web server has been established at www.thegleelab.org/PVP-SVM/PVP-SVM.html.

Installation of groundwater observation tubes OL-PVP30-35 at Olkiluoto in Eurajoki 2009

International Nuclear Information System (INIS)

Toropainen, V.

2009-10-01

In order to widen the Posivas groundwater monitoring network at Olkiluoto, Suomen Malmi Oy (Smoy) to install eight new groundwater observation tubes. The identification numbers of the groundwater observation tubes are OL-PVP30, OL-PVP31A and 31B, OL-PVP32, OL-PVP33, OL-PVP34A and 34B and OL-PVP35. The observation tubes were installed between January 28th and February 17th in 2009. The drilling rig used in the installation work was a GM-200 rig. Drilling equipment consisted of casing tubes (n 90/77 mm) with drilling bit, 55 mm geo rods and 64 mm drilling bits. Monitoring pipes (PVC, n 60/52 mm) were lowered into the holes inside the casings. The monitoring pipes consist of a lower section of riser pipe, a middle section of screen pipe and an upper section of riser pipe. The screen pipe slot size is 0.3 mm and the length of the screen section is one or two metres. Protective stainless steel covers with lock-up caps were installed around the monitoring tubes. In addition to the installation of the tubes, the work included observation of soil/drill cuttings quality during drilling, time-penetration measurements and water level measurements after installation. (orig.)

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

Science.gov (United States)

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.

Tribological properties of PVA/PVP blend hydrogels against articular cartilage.

Science.gov (United States)

Kanca, Yusuf; Milner, Piers; Dini, Daniele; Amis, Andrew A

2018-02-01

This research investigated in-vitro tribological performance of the articulation of cartilage-on- polyvinyl alcohol (PVA) and polyvinyl pyrrolidone (PVP) blend hydrogels using a custom-designed multi-directional wear rig. The hydrogels were prepared by repeated freezing-thawing cycles at different concentrations and PVA to PVP fractions at a given concentration. PVA/PVP blend hydrogels showed low coefficient of friction (COF) values (between 0.12 ± 0.01 and 0.14 ± 0.02) which were closer to the cartilage-on-cartilage articulation (0.03 ± 0.01) compared to the cartilage-on-stainless steel articulation (0.46 ± 0.06). The COF increased with increasing hydrogel concentration (p = 0.03) and decreasing PVP content at a given concentration (p < 0.05). The cartilage-on-hydrogel tests showed only the surface layers of the cartilage being removed (average volume loss of the condyles was 12.5 ± 4.2mm 3 ). However, the hydrogels were found to be worn/deformed. The hydrogels prepared at a higher concentration showed lower apparent volume loss. A strong correlation (R 2 = 0.94) was found between the COF and compressive moduli of the hydrogel groups, resulting from decreasing contact congruency. It was concluded that the hydrogels were promising as hemiarthroplasty materials, but that improved mechanical behaviour was required for clinical use. Copyright © 2017 Elsevier Ltd. All rights reserved.

High performances of dual network PVA hydrogel modified by PVP using borax as the structure-forming accelerator.

Science.gov (United States)

Huang, Min; Hou, Yi; Li, Yubao; Wang, Danqing; Zhang, Li

2017-01-01

A dual network hydrogel made up of polyvinylalcohol (PVA) crosslinked by borax and polyvinylpyrrolidone (PVP) was prepared by means of freezing-thawing circles. Here PVP was incorporated by linking with PVA to form a network structure, while the introduction of borax played the role of crosslinking PVA chains to accelerate the formation of a dual network structure in PVA/PVP composite hydrogel, thus endowing the hydrogel with high mechanical properties. The effects of both PVP and borax on the hydrogels were evaluated by comparing the two systems of PVA/PVP/borax and PVA/borax hydrogels. In the former system, adding 4.0% PVP not only increased the water content and the storage modulus but also enhanced the mechanical strength of the final hydrogel. But an overdose of PVP just as more than 4.0% tended to undermine the structure of hydrogels, and thus deteriorated hydrogels' properties because of the weakened secondary interaction between PVP and PVA. Likewise, increasing borax could promote the gel crosslinking degree, thus making gels show a decrease in water content and swelling ratio, meanwhile shrinking the pores inside the hydrogels and finally enhancing the mechanical strength of hydrogels prominently. The developed hydrogel with high performances holds great potential for applications in biomedical and industrial fields.

Optimasi Tablet Levofloksasin yang Mengandung Bahan Pengikat PVP K-30 dan Disintegran Vivasol

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Dina Ayu Fatmawati

2017-12-01

Full Text Available The aim of this research was to get optimal formula of levofloxacin tablet prepared with variation of PVP K-30 as binder and vivasol as disintegrant. The making of levofloxacin tablets was done by wet granulation. Tablet was prepared with various levels of PVP K-30 and disintegrant vivasol, compressed using a hydraulic press with 12 mm punch diameter, for 3 seconds. Physical quality (hardness, friability, and disintegration time and dissolution rate of tablet was evaluated. The optimization of the formula was done by factorial design of 22 factorial experiments with 2 factors (PVP K-30 and vivasol and 2 levels (2% and 4%. Optimization results showed that elevated levels of PVP K-30 increased tablet hardness, reduced friability of tablet, decreased disintegrating time, and increased dissolution rate of levofloxacin tablets. Meanwhile, elevated levels of vivasol increased the hardness of tablets, decreased the disintegrating time of tablets, decreased the dissolution rate of levofloxacin tablets, but did not affect the friability of tablets. In conclusion, the optimal tablet that meet the specifications of physical quality (hardness, friability, and disintegrating time and dissolution rate was made by 2.4 to 3.7% of PVP K-30 and 2.0 to 3.2% vivasol as shown in the feasible area of design space.

Ion transport property studies on PEO-PVP blended solid polymer electrolyte membranes

International Nuclear Information System (INIS)

Chandra, Angesh; Agrawal, R C; Mahipal, Y K

2009-01-01

The ion transport property studies on Ag + ion conducting PEO-PVP blended solid polymer electrolyte (SPE) membranes, (1 - x)[90PEO : 10AgNO 3 ] : xPVP, where x = 0, 1, 2, 3, 5, 7, 10 (wt%), are reported. SPE films were caste using a novel hot-press technique instead of the traditional solution cast method. The conventional solid polymeric electrolyte (SPE) film, (90PEO : 10AgNO 3 ), also prepared by the hot-press method and identified as the highest conducting composition at room temperature on the basis of PEO-AgNO 3 -salt concentration dependent conductivity studies, was used as the first-phase polymer electrolyte host into which PVP were dispersed as second-phase dispersoid. A two-fold conductivity enhancement from that of the PEO host could be achieved at room temperature for PVP blended SPE film composition: 98(90PEO : 10AgNO 3 ) : 2PVP. This has been referred to as optimum conducting composition (OCC). The formation of SPE membranes and material characterizations were done with the help of the XRD and DSC techniques. The ion transport mechanism in this SPE OCC has been characterized with the help of basic ionic parameters, namely ionic conductivity (σ), ionic mobility (μ), mobile ion concentration (n) and ionic transference number (t ion ). Solid-state polymeric batteries were fabricated using OCC as electrolyte and the cell-potential discharge characteristics were studied under different load conditions.

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

International Nuclear Information System (INIS)

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

2014-01-01

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

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

Energy Technology Data Exchange (ETDEWEB)

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

2014-10-15

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

Zeta potential and Raman studies of PVP capped Bi2S3 nanoparticles synthesized by polyol method

Science.gov (United States)

Tarachand, Sathe, Vasant G.; Okram, Gunadhor S.

2018-05-01

Here we report the synthesis and characterisation of polyvinylpyrrolidone (PVP) capped Bi2S3 nanoparticles via one step catalyst-free polyol method. Raman spectroscopy, dynamic light scattering and zeta potential analysis were performed on it. Rietveld refinement of powder XRD of PVP capped samples confirmed the formation of single phase orthorhombic Bi2S3 for all PVP capped samples. The presence of eight obvious Raman modes further confirmed the formation of stoichiometric Bi2S3. Dynamic light scattering (DLS) studies show a clear increase in hydrodynamic diameter for samples made with increasing PVP concentration. Particle size obtained from DLS and XRD (using Scherrer's formula) combine with change in full width half maxima of Raman modes collectively suggest overall improvement in crystallinity and quality of product on introducing PVP. In zeta potential (ζ) measurement, steric hindrance of carbon chains plays very crucial role and a systematic reduction of ζ value is observed for samples made with decreasing PVP concentration. An isoelectric point is obtained for sample made with low PVP (1g). Present results are likely to open a window for its medical and catalytic applications.

INVESTIGATIONS THE EFFECT OF EOSIN B DYE ON X- RAY DIFFRACTION PATTERN OF SILVER NITRATE DOPED PVP FILMS

Directory of Open Access Journals (Sweden)

Mahasin F. Hadi Al-Kadhemy

2017-07-01

Full Text Available In this research, X-ray diffraction of the powder (PVP polymer, Eosin B dye, and silver nitrate and (EB/PVP, AgNO3/PVP, EB/AgNO3/PVP films have been studied. Casting method is used to prepare homogeneous films on plastic petri dishes. All parameters accounted for the X-ray diffraction; full width half maximum (FWHM, Miller indices (hkl, size of crystalline (D, Specific Surface Area (S and Dislocation Density (δ.The nature of the structural of materials and films will be investigated. The XRD pattern of PVP polymer was amorphous structure with two broader peaks and the Eosin B dye and silver nitrate have crystalline structure. While the mixture between these materials led to appearing some crystalline peaks into XRD pattern of PVP polymer.

Nanostructurization effects in PVP-stabilized tetra-arsenic tetra-sulfide As_4S_4 nanocomposites

International Nuclear Information System (INIS)

Shpotyuk, O.; Bujňáková, Z.; Baláž, P.; Ingram, A.; Demchenko, P.; Kovalskiy, A.; Vlcek, M.; Shpotyuk, Ya.; Cebulski, J.; Dziedzic, A.

2017-01-01

Nanostructurization in three types of tetra-arsenic tetra-sulfide As_4S_4 polymorphs composed by (1) preferential β-As_4S_4, (2) realgar α-As_4S_4 and (3) admixture of As_4S_4 in the form of β-realgar, pararealgar and intermediate χ-phase subjected to mechanochemical ball milling in a water solution of polyvinylpyrrolidone (PVP) are characterized with multiexperimental structure-sensitive probes. Void structure of pelletized As_4S_4-PVP nanocomposites is probed by positron annihilation lifetime spectroscopy complemented with atomic-sensitive techniques such as X-ray powder diffraction, Raman scattering and scanning electron microscopy with energy-dispersive X-ray spectroscopy. Appearance of arsenolite As_2O_3 crystallites is character for all As_4S_4 polymorphs affected by wet milling. Positron annihilation lifetime data considered in terms of substitution positron-positronium trapping confirm complicated nature of nanocomposites. Modified x3-x2-coupling decomposition algorithm developed in addition to unconstrained x3-term fitting procedure is applied to parameterize annihilation channels in these nanocomposites. Interfacial free-volume voids between neighboring nanoparticles in PVP environment are defined as most favorable trapping sites, they being rather loosely composed by As_4S_4 crystallites in full respect to variety of crystallographic polymorphs used for milling. Detected annihilation channels are ascribed preferentially to intrinsic free-volume voids insensitive to trapping states at the surface of oxidized nanocomposites. - Highlights: • PVP-stabilized tetra-arsenic tetra-sulfide nanocomposites prepared by wet milling. • As_4S_4-PVP composites by complementary atomic-specific and deficient structure probes. • Surface oxidation due to crystalline arsenolite As_2O_3 under wet milling. • Free-volume structure of PVP-stabilized As_4S_4 nanocomposites by PAL spectroscopy. • x3-x2-coupling decomposition algorithm to treat PAL data for As_4S_4

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

Energy Technology Data Exchange (ETDEWEB)

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

2010-07-01

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

Enhancing Photocatalytic Degradation of Methyl Blue Using PVP-Capped and Uncapped CdSe Nanoparticles

Directory of Open Access Journals (Sweden)

Kgobudi Frans Chepape

2017-01-01

Full Text Available Quantum confinement of semiconductor nanoparticles is a potential feature which can be interesting for photocatalysis, and cadmium selenide is one simple type of quantum dot to use in the following photocatalytic degradation of organic dyes. CdSe nanoparticles capped with polyvinylpyrrolidone (PVP in various concentration ratios were synthesized by the chemical reduction method and characterized. The transmission electron microscopy (TEM analysis of the samples showed that 50% PVP-capped CdSe nanoparticles were uniformly distributed in size with an average of 2.7 nm and shape which was spherical-like. The photocatalytic degradation of methyl blue (MB in water showed efficiencies of 31% and 48% when using uncapped and 50% PVP-capped CdSe nanoparticles as photocatalysts, respectively. The efficiency of PVP-capped CdSe nanoparticles indicated that a complete green process can be utilized for photocatalytic treatment of water and waste water.

Studies on polymer electrolyte poly(vinyl) pyrrolidone (PVP) complexed with ionic liquid: Effect of complexation on thermal stability, conductivity and relaxation behaviour

Energy Technology Data Exchange (ETDEWEB)

Saroj, A.L. [Department of Physics, Banaras Hindu University, Varanasi, 221005 (India); Singh, R.K., E-mail: rksingh_17@rediffmail.com [Department of Physics, Banaras Hindu University, Varanasi, 221005 (India); Chandra, S. [Department of Physics, Banaras Hindu University, Varanasi, 221005 (India)

2013-03-01

Highlights: Black-Right-Pointing-Pointer PVP + IL based polymer electrolyte films have been prepared and studied. Black-Right-Pointing-Pointer The complexation/interaction of PVP with IL has been confirmed by FT-IR analysis. Black-Right-Pointing-Pointer The conductivity and relaxation frequency increases with increasing IL content. Black-Right-Pointing-Pointer Two relaxation peaks for complexed and uncomplexed PVP with IL have been observed. - Abstract: Polymer electrolyte films of PVP + x wt% ionic liquid (IL) (1-ethyl-3-methylimidazolium tetrafluoroborate [EMIM][BF{sub 4}]) for x = 0, 5, 10, 15, 20, 25 wt% have been prepared using solution cast technique. These films were characterized by TGA, DSC, FT-IR and ac impedance spectroscopy techniques. From XRD studies it is found that the inclusion of IL increases the amorphocity of polymeric membranes. DSC thermograms show that the glass transition (T{sub g}) and melting temperatures (T{sub m}) of PVP shift upon complexation with IL. FT-IR analysis shows the complexation of PVP with IL. Thermogravimetric studies show that PVP decomposes in a single step while PVP/IL membranes exhibit two step decomposition; lower value of decomposition temperature corresponds to the decomposition of PVP/IL complex while the higher decomposition temperature has been attributed to the decomposition of PVP. The decomposition temperature of PVP/IL complex decreases with the increasing amount of IL in the PVP membrane. Temperature dependence of conductivity and dielectric relaxation frequencies have also been studied for PVP and PVP/IL membranes. Both show thermally activated Arrhenius behaviour.

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

Science.gov (United States)

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.

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

Directory of Open Access Journals (Sweden)

Alireza Homayouni

2014-05-01

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

"Marvin, the Paranoid Android": The Case of an Alpha-PVP User in the Expanding Galaxy of NPS.

Science.gov (United States)

Pierluigi, Simonato; Laura, Bulsis; Attilio, Negri; Gurjeet K, Bansal; Gloria, Pessa; Davide, Mioni; Borgherini, Giuseppe; Giovanni, Martinotti; Fabrizio, Schifano; Perini, Giulia; Ornella, Corazza

2018-05-16

Alpha-PVP can be defined as a novel psychoactive substance (NPS)-more specifically, a novel synthetic cathinone with unpredictable stimulant effects in humans. "Marvin" arrived at a Dual Diagnosis Unit at Parco dei Tigli, Italy. He underwent a 30-day rehabilitation program to overcome his problematic Alpha-PVP use as a psychonaut. We conducted an online search to understand the properties of Alpha-PVP and its presence in scientific literature, reviewing official reports and the online drug market (e.g., fora, webpages). In the Dual Diagnosis Unit, Marvin completed the 30-day rehabilitation program that included assessments and group and individual cognitive behavioral therapy. Alpha-PVP is a synthetic cathinone with stimulant properties, available in the online market but with unpredictable effects in humans. The present case reports an important risk of psychosis in a psychonaut patient who arrived and declared its intense use before admission to our Unit. This article describes the psychopathological effects of the novel compound Alpha-PVP in a psychonaut patient. Patients attending clinics that have used Alpha-PVP pose a new challenge for traditional services of mental health and addiction.

Influence of PVP molecular weight on the microwave assisted in situ amorphization of indomethacin

DEFF Research Database (Denmark)

Doreth, Maria; Löbmann, Korbinian; Priemel, Petra

2018-01-01

. After plasticization by moisture, PVP K12 reached a Tg below ambient temperature (16 ± 2 °C) indicating that the Tg of the plasticized polymer is a key factor for the success of in situ amorphization. DSC analysis showed that the amorphized drug was part of a ternary glass solution consisting of IND......, PVP K12 and water. In dissolution tests, IND:PVP K12 compacts showed a delayed initial drug release due to a lack of compact disintegration, but reached a higher total drug release eventually. In summary, this study showed that the microwave assisted in situ amorphization was highly dependent...... on the Tg of the plasticized polymer....

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

CSIR Research Space (South Africa)

Labuschagne, Philip W

2011-05-01

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

Potential Application of Gamma Irradiated Polyvinyl Pyrrolidone (PVP) - Starch Hydrogel As Fever Cooling Plaster

International Nuclear Information System (INIS)

Darmawan Darwis; Lely Hardiningsih

2010-01-01

Research on the development of hydrogel for cooling fever by using gamma irradiation technique has been done. The hydrogel was prepared by irradiating the mixture of PVP with concentration of 7% (w/v) and starch with various concentrations using gamma ray at irradiation dose of 20 to 40 kGy. The results showed that optimum starch concentration to make solid constituent of PVP-starch prior to irradiation were 10-15%. Gel fraction of PVP-starch hydrogel showed an increase by increasing of irradiation dose up to 35 kGy, and acceleration of irradiation dose did not have any effect on gel fraction. At the same irradiation dose, there was no influence of starch concentration on gel fraction. Maximum gel fraction was achieved at 35 kGy irradiation dose. Water content of PVP-Starch hydrogel with starch concentration of 10 to 15% was in the range of 73 - 76%. Water content of hydrogel depends on starch concentration, while irradiation dose does not give any effect on water content of hydrogel. Hydrogel with high water content is potential to be used for fever cooling. Hydrogel PVP-Starch with starch concentration of 10% irradiated by gamma irradiation at the dose of 35 kGy had the ability to reduce water temperature from 40°C to 36°C in 21 minutes, while it took 24 minutes for the hydrogel with starch concentration of 12.5 and 15%. Commercial cooling pad hydrogel need 24 minutes to reduce temperature of water from 40°C to 36°C. Based on these results, it can be concluded that PVP hydrogel with 10% starch content showed faster cooling effect compared to hydrogel with 12.5 and 15 % starch content as well as the commercial hydrogel. Beside these advantages, the hydrogel obtained has some disadvantages such as low stickiness, brittle and opaque. (author)

Temperature and concentration calibration of aqueous polyvinylpyrrolidone (PVP solutions for isotropic diffusion MRI phantoms.

Directory of Open Access Journals (Sweden)

Friedrich Wagner

Full Text Available To use the "apparent diffusion coefficient" (Dapp as a quantitative imaging parameter, well-suited test fluids are essential. In this study, the previously proposed aqueous solutions of polyvinylpyrrolidone (PVP were examined and temperature calibrations were obtained. For example, at a temperature of 20°C, Dapp ranged from 1.594 (95% CI: 1.593, 1.595 μm2/ms to 0.3326 (95% CI: 0. 3304, 0.3348 μm2/ms for PVP-concentrations ranging from 10% (w/w to 50% (w/w using K30 polymer lengths. The temperature dependence of Dapp was found to be so strong that a negligence seems not advisable. The temperature dependence is descriptively modelled by an exponential function exp(c2 (T - 20°C and the determined c2 values are reported, which can be used for temperature calibration. For example, we find the value 0.02952 K-1 for 30% (w/w PVP-concentration and K30 polymer length. In general, aqueous PVP solutions were found to be suitable to produce easily applicable and reliable Dapp-phantoms.

Solvation consequences of polymer PVP with biological buffers MES, MOPS, and MOPSO in aqueous solutions

International Nuclear Information System (INIS)

Gupta, Bhupender S.; Chen, Bo-Ren; Lee, Ming-Jer

2015-01-01

Highlights: • Densities and viscosities data for aqueous solutions with PVP and/or buffer. • The studied buffers include MES, MOPS, and MOPSO. • DFT was used to estimate the binding energies of the (PVP + buffer) complexes. • The viscosity data were correlated with the Jones–Dole equation. • The investigated buffers behave as Kosmotropies. - Abstract: Densities and viscosities were measured for the aqueous buffer (MES, MOPS, or MOPSO) solutions containing different concentrations of polyvinylpyrrolidone (PVP) (5, 10, 15, 20 and 30) mass% at temperatures from (298.15 to 318.15) K under atmospheric pressure. The DFT calculations were also performed and the binding energies of the possible (PVP + buffer) complexes were obtained. The experimental and computational results reveal the interactions of the PVP with the constituent compounds in the aqueous buffer solutions. Additionally we have explored the solvation behavior of the buffers by measuring the densities and the viscosities data of the aqueous buffer solutions from (0.0 to 1.0) mol · kg"−"1 at temperatures from (298.15 to 318.15) K. The viscosity results were correlated with the Jones–Dole equation. The correlated results confirmed that all the investigated buffers behave as Kosmotropes (structure makers).

Chemoselective hydrogenation of arenes by PVP supported Rh nanoparticles

DEFF Research Database (Denmark)

Ibrahim, Mahmoud; Poreddy, Raju; Philippot, Karine

2016-01-01

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

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

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Halimah Mohamed Kamari

2014-04-01

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

Physico - chemical characterization of gamma irradiated PVP-honey-glycerine hydrogel

International Nuclear Information System (INIS)

Darmawan Darwis; Lely Hardiningsih; Farah Nurlidar

2010-01-01

Research to investigate physico-chemical characterizatics of hydrogel wound dressing containing 6% (b/v) of honey and various concentrations of glycerine from 0-5% (b/v) has been done. Nine series of hydrogel formulas with various composition of PVP hydrogel were irradiated using gamma rays at a dose of 25 kGy. The results showed that addition of honey 6% and glycerine up to 5% lead to the formation of hydrogel with following properties: sterile, transparence, browning color, improved flexibility, conformability to skin and resistance against mould. The PVP-honey-glycerine hydrogel also showed lower water favor evaporation at 37 o C and higher water absorption properties compared to basic formula (without additional of honey and glycerine). (author)

Polyvinylpyrrolidone (PVP)-assisted hydrothermal synthesis of luminescent YVO4:Eu3+ microspheres

International Nuclear Information System (INIS)

Wang Juan; Xu Yunhua; Hojamberdiev, Mirabbos; Wang Mingqiong; Zhu Gangqiang

2010-01-01

Spherical YVO 4 :Eu 3+ microstructures were hydrothermally synthesized by the reaction of NH 4 VO 3 , Y 2 O 3 , and Eu 2 O 3 at 180 deg. C for 24 h with the assistance of polyvinylpyrrolidone (PVP) as a surfactant. The resulting products were characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), and photoluminescence (PL) spectroscopy. The experimental results showed that ball-like YVO 4 :Eu 3+ microspheres with a diameter of about 4-5 μm, corresponding to the SEM observations, formed at 180 deg. C for 24 h using 0.2 g PVP with the molecular weight of 20,000 g mol -1 . The amount of PVP and the reaction time of hydrothermal processing were found to play a key role in the formation of YVO 4 :Eu 3+ microspheres. It has been observed that the relative luminescence intensities of the as-synthesized samples increased with increasing hydrothermal reaction times due mainly to the increase of crystallinity.

Development of swellable local implants of a polyethyleneimine-poly(vinyl pyrrolidone) (PEI-PVP) hydrogel as a socket filler.

Science.gov (United States)

Chang, Ching-Wen; Ho, Hsiu-O; Lo, Yi-June; Lee, Sheng-Yang; Yang, You-Ren; Sheu, Ming-Thau

2012-01-01

In this study, hydrogels composed of polyethyleneimine (PEI) and poly(vinyl pyrrolidone) K90 (PVP) cross-linked with various concentrations (0, 0.125, 0.25 and 0.5%) of glutaraldehyde were evaluated as a hydrogel filler for the local delivery of lidocaine after tooth extraction. The drug-release kinetics, swellability, cytotoxicity and wound healing after tooth extraction of these non-cross-linked and cross-linked PEI-PVP hydrogels were examined in male beagles and compared to values using Spongostan(®). Results demonstrated that the extent of cross-linking influenced the swelling of the resulting hydrogel, but the drug-release rates were similar. No significant changes were observed in gingival fibroblasts in contact with the PEI- PVP hydrogels or Spongostan(®). In the in vivo study, PEI-PVP hydrogels showed good retention in the socket for 2 days and showed comparable wound-healing rates within 2 weeks with those of Spongostan(®). In conclusion, PEI-PVP hydrogels are suitable for use as socket-dressing materials, and the release of local anaesthesia from PEI-PVP hydrogels can be sustained for a desirable period of time to prevent pain after a tooth extraction.

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

International Nuclear Information System (INIS)

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

2016-01-01

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

Fabrication of CH3NH3PbI3/PVP Composite Fibers via Electrospinning and Deposition

Science.gov (United States)

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

2015-01-01

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

Fabrication of CH3NH3PbI3/PVP Composite Fibers via Electrospinning and Deposition

Directory of Open Access Journals (Sweden)

Li-Min Chao

2015-08-01

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

Hydrogels of polyvinylpyrrolidone (PVP) and poly(acrylic acid) (PAA) synthesized by radiation-induced crosslinking of homopolymers

Science.gov (United States)

Kadłubowski, Sławomir; Henke, Artur; Ulański, Piotr; Rosiak, Janusz M.

2010-03-01

pH-sensitive PVP-PAA hydrogels have been prepared by electron-beam-induced irradiation at pH close to pKa of carboxylic groups. Protonation of these groups promoted the formation of hydrogen bonds between the PAA and PVP segments within the crosslinked structure and caused interpolymer complex formation. To demonstrate possible future application of such gels, we tested them as simple chemical detectors. When loaded with glucose oxidase, the PAA-PVP gel's turbidity and shrinkage was triggered by the presence of glucose due to a drop in pH caused by the enzymatic reaction.

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

Energy Technology Data Exchange (ETDEWEB)

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

2010-07-01

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

Synthesis and characterization of semi-IPNs based on PVP and PLLA

International Nuclear Information System (INIS)

Camilo, A.P.R.; Mano, V.; Felisberti, M.I.

2010-01-01

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

Nanostructurization effects in PVP-stabilized tetra-arsenic tetra-sulfide As{sub 4}S{sub 4} nanocomposites

Energy Technology Data Exchange (ETDEWEB)

Shpotyuk, O., E-mail: olehshpotyuk@yahoo.com [Institute of Physics of Jan Dlugosz University in Czestochowa, 13/15, Al. Armii Krajowej, Czestochowa, 42200 (Poland); Vlokh Institute of Physical Optics, 23, Dragomanov Str., Lviv, 79005 (Ukraine); Scientific Research Company “Carat”, 202, Stryjska Str., 79031, Lviv (Ukraine); Bujňáková, Z.; Baláž, P. [Institute of Geotechnics of Slovak Academy of Sciences, 45, Watsonova Str., Košice, 04001 (Slovakia); Ingram, A. [Opole University of Technology, 75, Ozimska Str., Opole, 45370 (Poland); Demchenko, P. [Ivan Franko National University of Lviv, 1, Universytetska Str., 79000 Lviv (Ukraine); Kovalskiy, A. [Department of Physics & Astronomy, Austin Peay State University, Clarksville, TN, 37044 (United States); Vlcek, M. [Department of General and Inorganic Chemistry, Faculty of Chemistry, University of Pardubice, 532 10, Pardubice (Czech Republic); Shpotyuk, Ya. [Ivan Franko National University of Lviv, 1, Universytetska Str., 79000 Lviv (Ukraine); Centre for Innovation and Transfer of Natural Sciences and Engineering Knowledge, 1, Pigonia Str., 35310, Rzeszow (Poland); Cebulski, J.; Dziedzic, A. [Centre for Innovation and Transfer of Natural Sciences and Engineering Knowledge, 1, Pigonia Str., 35310, Rzeszow (Poland)

2017-01-15

Nanostructurization in three types of tetra-arsenic tetra-sulfide As{sub 4}S{sub 4} polymorphs composed by (1) preferential β-As{sub 4}S{sub 4}, (2) realgar α-As{sub 4}S{sub 4} and (3) admixture of As{sub 4}S{sub 4} in the form of β-realgar, pararealgar and intermediate χ-phase subjected to mechanochemical ball milling in a water solution of polyvinylpyrrolidone (PVP) are characterized with multiexperimental structure-sensitive probes. Void structure of pelletized As{sub 4}S{sub 4}-PVP nanocomposites is probed by positron annihilation lifetime spectroscopy complemented with atomic-sensitive techniques such as X-ray powder diffraction, Raman scattering and scanning electron microscopy with energy-dispersive X-ray spectroscopy. Appearance of arsenolite As{sub 2}O{sub 3} crystallites is character for all As{sub 4}S{sub 4} polymorphs affected by wet milling. Positron annihilation lifetime data considered in terms of substitution positron-positronium trapping confirm complicated nature of nanocomposites. Modified x3-x2-coupling decomposition algorithm developed in addition to unconstrained x3-term fitting procedure is applied to parameterize annihilation channels in these nanocomposites. Interfacial free-volume voids between neighboring nanoparticles in PVP environment are defined as most favorable trapping sites, they being rather loosely composed by As{sub 4}S{sub 4} crystallites in full respect to variety of crystallographic polymorphs used for milling. Detected annihilation channels are ascribed preferentially to intrinsic free-volume voids insensitive to trapping states at the surface of oxidized nanocomposites. - Highlights: • PVP-stabilized tetra-arsenic tetra-sulfide nanocomposites prepared by wet milling. • As{sub 4}S{sub 4}-PVP composites by complementary atomic-specific and deficient structure probes. • Surface oxidation due to crystalline arsenolite As{sub 2}O{sub 3} under wet milling. • Free-volume structure of PVP-stabilized As{sub 4}S{sub 4

Enhancing Photocatalytic Degradation of Methyl Blue Using PVP-Capped and Uncapped CdSe Nanoparticles

OpenAIRE

Chepape, Kgobudi Frans; Mofokeng, Thapelo Prince; Nyamukamba, Pardon; Mubiayi, Kalenga Pierre; Moloto, Makwena Justice

2017-01-01

Quantum confinement of semiconductor nanoparticles is a potential feature which can be interesting for photocatalysis, and cadmium selenide is one simple type of quantum dot to use in the following photocatalytic degradation of organic dyes. CdSe nanoparticles capped with polyvinylpyrrolidone (PVP) in various concentration ratios were synthesized by the chemical reduction method and characterized. The transmission electron microscopy (TEM) analysis of the samples showed that 50% PVP-capped Cd...

Poly(vinyl pyrrolidone) (PVP) hydrogels study for ophthalmologic area utilization

International Nuclear Information System (INIS)

Amaral, Renata Hage; Rogero, Sizue Ota; Lugao, Ademar Benevolo; Cruz, Aurea S.; Sacramento, Rogerio S.; Lima Filho, Acacio A. Souza; Schor, Paulo

2005-01-01

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

Evaluation of a New Biosensor Based on in Situ Synthesized PPy-Ag-PVP Nanohybrid for Selective Detection of Dopamine.

Science.gov (United States)

Vellaichamy, Balakumar; Periakaruppan, Prakash; Paulmony, Tharmaraj

2017-02-09

In the present work, in situ synthesis of polypyrrole-silver-polyvinylpyrrolidone (PPy-Ag-PVP) nanohybrid using AgNO 3 as an oxidant and polyvinylpyrrolidone (PVP) as a stabilizer and surfactant is demonstrated. The obtained ternary PPy-Ag-PVP nanohybrid was characterized by UV-vis, FT-IR, XRD, Raman, TGA, SEM, and HR-TEM analysis. Further the synthesized PPy-Ag-PVP has been investigated for its selective and sensitive sensing of dopamine (DA). The PPy-Ag-PVP modified glassy carbon electrode shows a reversible electrochemical behavior with superior response for DA. The limit of detection and limit of quantification are found to be 0.0126 and 0.042 μM (S/N = 3 and 10), respectively, with remarkable sensitivity (7.26 μA mM -1 cm -2 ). The practical application of the present modified electrode has been validated by determining the concentration of DA in human urine samples of different age group.

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

Directory of Open Access Journals (Sweden)

Eun-Sol Ha

2014-12-01

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

Transport and accumulation of PVP-Hypericin in cancer and normal cells characterized by image correlation spectroscopy techniques.

Science.gov (United States)

Penjweini, Rozhin; Smisdom, Nick; Deville, Sarah; Ameloot, Marcel

2014-05-01

PVP-Hypericin (PVP: polyvinylpyrrolidone) is a potent anti-cancer photosensitizer for photodynamic diagnosis (PDD) and therapy (PDT). However, cellular targets and mechanisms involved in the cancer-selectivity of the photosensitizer are not yet fully understood. This paper gives new insights into the differential transport and localization of PVP-Hypericin in cancer and normal cells which are essential to unravel the mechanisms of action and cancer-selectivity. Temporal (TICS) and spatiotemporal (STICS) image correlation spectroscopy are used for the assessment of PVP-Hypericin diffusion and/or velocity in the case of concerted flow in human cervical epithelial HeLa and human lung carcinoma A549 cells, as well as in human primary dendritic cells (DC) and human peripheral blood mononuclear cells (PBMC). Spatiotemporal image cross-correlation spectroscopy (STICCS) based on organelle specific fluorescent labeling is employed to study the accumulation of the photosensitizer in nucleus, mitochondria, early-endosomes and lysosomes of the cells and to assess the dynamics of co-migrating molecules. Whereas STICS and TICS did not show a remarkable difference between the dynamics of PVP-Hypericin in HeLa, A549 and DC cells, a significantly different diffusion rate of the photosensitizer was measured in PBMC. STICCS detected a stationary accumulation of PVP-Hypericin within the nucleus, mitochondria, early endosomes and lysosomes of HeLa and A549 cells. However, significant flow due to the directed motion of the organelles was detected. In contrast, no accumulation in the nucleus and mitochondria of DC and PBMC could be monitored. Copyright © 2014 Elsevier B.V. All rights reserved.

Novel asymmetric chitosan/PVP/nanocellulose wound dressing: In vitro and in vivo evaluation.

Science.gov (United States)

Poonguzhali, R; Khaleel Basha, S; Sugantha Kumari, V

2018-06-01

The present study was to develop a novel chitosan based symmetric and asymmetric bionanocomposite for potential wound dressing application. Chitosan (C)/Poly (vinyl pyrrolidone) (P)/nanocellulose (NC) membrane were fabricated by salt leaching method with the addition of 3% and 5% wt of nanocellulose. To obtain asymmetric material one side of the membrane was coated by stearic acid (S) which could form hydrophobic surface and another side acts as a hydrophilic surface. Nanocellulose of size 2-10nm was synthesized and characterized by TEM analysis. SEM showed the hydrophilic surface of asymmetric bionanocomposite consists of porous structure and hydrophobic surface is smooth and homogeneous. The results revealed that the Chitosan/PVP/Nanocellulose 3%-Stearic acid (CPNC3%-S) had a moderate swelling ratio, porosity, barrier and mechanical properties. Incorporation of nanocellulose into chitosan/PVP matrix could enhance the antibacterial activity. The hydrophobic surface of the CPNC3%-S bionanocomposite shows water repellent and antiadhesion properties towards E. coli bacteria and also the hydrophilic surface exhibit excellent antibacterial property and cytotoxicity towards bacterial pathogens. In vivo wound healing test shows better re-epithelialization and wound contraction compared with control and Chitosan/PVP-stearic acid (CP-S) bionanocomposite. Asymmetric bionanocomposite Chitosan/PVP/Nanocellulose coated with 3%-Stearic acid (CPNC3%-S) exhibited very good invitro cytocompatibility and enabled a faster wound healing than symmetric dressing, hence showing great potential to be applied as wound dressings. Copyright © 2018 Elsevier B.V. All rights reserved.

Semi-commercialization of PVP-carrageenan hydrogel

International Nuclear Information System (INIS)

Relleve, Lorna S.; Abad, Lucille V.; Aranilla, Charito T.; Dela Rosa, A.M.

2008-01-01

The Philippine Nuclear Research Institute (PNRI) has developed the PVP-Carrageenan hydrogel wound dressing by radiation processing. The PVP-Carrageenan hydrogel has undergone clinical testing for burn and bedsores. It has already a pending patent application (No. 1-2000-02471) at the Philippine Patent Office. The techno-economic feasibility study has also been completed. In order to commercialize this product, a project on semi-commercialization in partnership with the investor was proposed to Technology Incubation for Commercialization (TECHNICOM), a technology transfer program of the Department of Science and Technology (DOST). TECHNICOM was established in 2003 under the National Science and Technology Plan (2002-2020) as a strategic technology transfer program. The program aims to identify key technological breakthroughs especially those generated by R and D institutes. It can intervene through the following: technology assessment/commercial prototype development; business plan/feasibility study preparation; intellectual property rights protection; technology valuation negotiation and licensing; semi-commercial production assistance and training/consultancy services. High technology applications with commercial potentials are given priority. Under semi-commercialization stage, government funds will be provided to match private sector investment in the commercial application of a particular technology innovation. This will lessen the risk of commercialization and ensure commitment from the investors. Commercial success in the shortest time is ensured since scientist can then work closely with the private sector at the production floor while testing the gaps in the technology. (author)

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

Energy Technology Data Exchange (ETDEWEB)

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

2015-05-12

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

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

International Nuclear Information System (INIS)

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

2016-01-01

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

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

Energy Technology Data Exchange (ETDEWEB)

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

2016-02-15

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

To study the linear and nonlinear optical properties of Se-Te-Bi-Sn/PVP (polyvinylpyrrolidone) nanocomposites

Science.gov (United States)

Tyagi, Chetna; Yadav, Preeti; Sharma, Ambika

2018-05-01

The present work reveals the optical study of Se82Te15Bi1.0Sn2.0/polyvinylpyrrolidone (PVP) nanocomposites. Bulk glasses of chalcogenide was prepared by well-known melt quenching technique. Wet chemical technique is proposed for making the composite of Se82Te15Bi1.0Sn2.0 and PVP polymer as it is easy to handle and cost effective. The composites films were made on glass slide from the solution of Se-Te-Bi-Sn and PVP polymer using spin coating technique. The transmission as well as absorbance is recorded by using UV-Vis-NIR spectrophotometer in the spectral range 350-700 nm. The linear refractive index (n) of polymer nanocomposites are calculated by Swanepoel approach. The linear refractive index (n) PVP doped Se82Te15Bi1.0Sn2.0 chalcogenide is found to be 1.7. The optical band gap has been evaluated by means of Tauc extrapolation method. Tichy and Ticha model was utilized for the characterization of nonlinear refractive index (n2).

Effect of chitosan addition and gamma radiation on polymeric blends of PVP and PVAL

International Nuclear Information System (INIS)

Terence, M.C.; Castro, P.J.; Miranda, L.F.; Faldini, S.B.

2010-01-01

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

Review of the use of povidone-iodine (PVP-I) in the treatment of burns.

Science.gov (United States)

Steen, M

1993-01-01

Local infection and burn wound sepsis are one of the most severe problems in the treatment of thermally injured patients. Early surgical treatment and the use of topical antiseptics led to a decrease in the infection rate and significantly improved the survival rate of burns patients within the last twenty-five years. Many antiseptics are used in the treatment of burns. Silver nitrate, silver sulphadiazine, sulfamylon and povidone-iodine (PVP-I) are the most common substances used worldwide in burn care facilities. Clinical studies demonstrate that treatment with PVP-I is the most effective against bacterial and fungal infection. Several methodological problems however arise from direct comparison between these antiseptics, and local and systemic adverse effects can make the right choice difficult. Some case reports documented possible side effects in the treatment of patients with PVP-I, leading to general concerns about this treatment. Absorption of iodine and possible changes in thyroid hormones are well known, but evaluation of the clinical consequences is controversial. Reports of severe metabolic acidosis and renal insufficiency with lethal results have condemned the use of PVP-I in the treatment of extensive burns. The case reports, however, dealt with patients suffering from general morbidity and sepsis and therefore these single reports may not be generally valid. Local treatment of burns may cause further problems. The beneficial effect of a decrease of bacterial counts in deeper tissue may be confounded by other effects delaying wound healing, as shown in some experimental studies. Controlled clinical investigations on burn patients however are still missing. The paper will discuss these topics in detail referring to the treatment of burns with PVP-I. It is based on a critical review of the literature and the author's own experience in burns therapy.

Evaluation of structural and optical properties of Ce3+ ions doped (PVA/PVP) composite films for new organic semiconductors

Science.gov (United States)

Ali, F. M.; Kershi, R. M.; Sayed, M. A.; AbouDeif, Y. M.

2018-06-01

Polymer blend films based on Polyvinyl alcohol (PVA)/Poly(vinylpyrrolidone) (PVP) doped with different concentration of cerium ions [(PVA/PVP)-x wt.% Ce3+] (x = 3%, 5%, 10% and 15%) were prepared by the conventional solution casting technique. The characteristics of the prepared polymer composite films were studied using X-ray diffraction (XRD), FT-IR and UV-Vis. spectroscopy. The XRD patterns of the investigated samples revealed a clear reduction on the structural parameters such as crystallinity degree and cluster size D of the doped PVA/PVP blend films compared with the virgin one whereas there is no big difference in the d spacing of the product composite films. Significant changes in FT-IR spectra are observed which reveal an interactions between the cerium ions and PVA/PVP blends. The absorption spectra in the ultraviolet-visible region showed a wide red shift in the fundamental absorption edge of (PVA/PVP)-x wt. % Ce3+ composites. The optical gap Eg gradually decreased from 4.54 eV for the undoped PVA/PVP film to 3.10 eV by increasing Ce3+ ions content. The optical dispersion parameters have been analyzed according to Wemple-Didomenico single oscillator model. The dispersion energy Ed, the single oscillator energy Eo, the average inter-band oscillator wavelength λo and the static refractive index no are strongly affected by cerium ions doping. Cerium ions incorporation in PVA/PVP blend films leads to a significant increase in the refractive index and decrease in the optical gap. These results are likely of great important in varieties of applications including polymer waveguides, organic semiconductors, polymer solar cells and optoelectronics devices.

Biological compatibility test on films of added SEO [poly(dimethyl siloxane)-co-poly(ethylene oxide)] PVP

International Nuclear Information System (INIS)

Rogero, Sizue O.; Souza-Bazzi, Aurea de; Higa, Olga Z.

1999-01-01

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

Dissolution rate enhancement of the poorly water-soluble drug Tibolone using PVP, SiO2, and their nanocomposites as appropriate drug carriers.

Science.gov (United States)

Papadimitriou, Sofia; Bikiaris, Dimitrios

2009-09-01

Creation of immediate release formulations for the poorly water-soluble drug Tibolone through the use of solid dispersions (SDs). SD systems of Tibolone (Tibo) with poly(vinylpyrrolidone) (PVP), fumed SiO(2) nanoparticles, and their corresponding ternary systems (PVP/SiO(2)/Tibo) were prepared and studied in order to produce formulations with enhanced drug dissolution rates. The prepared SDs were characterized by the use of differential scanning calorimetry and wide-angle X-ray diffractometry techniques. Also dissolution experiments were performed. From the results it was concluded that PVP as well as SiO(2) can be used as appropriate carriers for the amorphization of Tibo, even when the drug is used at high concentrations (20-30%, w/w). This is due to the evolved interactions taking place between the drug and the used carriers, as was verified by Fourier transform infrared spectroscopy. At higher concentrations the drug was recrystallized. Similar are the observations on the ternary PVP/SiO(2)/Tibo SDs. The dissolution profiles of the drug in PVP/Tibo and SiO(2)/Tibo SDs are directly dependent on the physical state of the drug. Immediately release rates are observed in SD with low drug concentrations, in which Tibo was in amorphous state. However, these release profiles are drastically changed in the ternary PVP/SiO(2)/Tibo SDs. An immediate release profile is observed for low drug concentrations and an almost sustained release as the concentration of Tibo increases. This is due to the weak interactions that take place between PVP and SiO(2), which result in alterations of the characteristics of the carrier (PVP/SiO(2) nanocomposites). Immediate release formulation was created for Tibolone as well as new nanocomposite matrices of PVP/SiO((2)), which drastically change the release profile of the drug to a sustained delivery.

Effects of polymerization degree on recovery behavior of PVA/PVP hydrogels as potential articular cartilage prosthesis after fatigue test

Directory of Open Access Journals (Sweden)

Y. Shi

2016-02-01

Full Text Available Poly (vinyl alcohol/poly (vinyl pyrrolidone (PVA/PVP hydrogels with various polymerization degrees of PVA were synthesized by a repeated freezing-thawing method. The influence of polymerization degree on microstructure, water content, friction coefficient, compressive fatigue and recovery properties of PVA/PVP hydrogels were investigated. The results showed that higher polymerization degree resulted in larger compressive modulus and lower friction coefficient. The fatigue behaviors of PVA/PVP hydrogels were evaluated under sinusoidal compressive loading from 200 to 800 N at 5 Hz for up to 50 000 cycles. The unconfined uniaxial compressive tests of PVA/PVP hydrogels were performed before and after fatigue test. During the fatigue test, the height of the hydrogel rapidly decreased at first and gradually became stable with loading cycles. The compressive tangent modulus measured 0 h after fatigue was significantly larger than the values obtained before test, and then the modulus recovered to its original level for 48 h after test. However, the geometry of hydrogels could not return to the original level due to the creep effects. PVA/PVP hydrogels prepared with lower polymerization degree showed better recovery capability than that prepared with high polymerization degree.

Enhancement of antibacterial activity in nanofillers incorporated PSF/PVP membranes

Science.gov (United States)

Pramila, P.; Gopalakrishnan, N.

2018-04-01

An attempt has been made to investigate the nanofillers incorporated polysulfone (PSF) and polyvinylpyrrolidone (PVP) polymer membranes prepared by phase inversion method. Initially, the nanofillers, viz, Zinc Oxide (ZnO) nanoparticle, Graphene Oxide-Zinc Oxide (GO-ZnO) nanocomposite were synthesized and then directly incorporated into PSF/PVP blend during the preparation of membranes. The prepared membranes have been subjected to FE-SEM, AFM, BET, contact angle, tensile test and anti-bacterial studies. Significant membrane morphologies and nanoporous properties have been observed by FE-SEM and BET, respectively. It has been observed that hydrophilicity, mechanical strength and water permeability of the ZnO and GO-ZnO incorporated membranes were enhanced than bare membrane. Antibacterial activity was assessed by measuring the inhibition zones formed around the membrane by disc-diffusion method using Escherichia coli (gram-negative) as a model bacterium. Again, it has been observed that nanofillers incorporated membrane exhibits high antibacterial performance compared to bare membrane.

PVP-coated silver nanoparticles showing antifungal improved activity against dermatophytes

Science.gov (United States)

Silva, Edgar; Saraiva, Sofia M.; Miguel, Sónia P.; Correia, Ilídio J.

2014-11-01

Fungal infections affecting human beings have increased during the last years and the currently available treatments, when administered for long periods, trigger microbial resistance. Such demands the development of new viable therapeutic alternatives. Silver is known since the antiquity by its antimicrobial properties and, herein, it was used to produce two types of nanoparticles (NPs), uncoated and coated with polyvinylpyrrolidone (PVP), which were aimed to be used in fungal infection treatment. NPs properties were characterized by Transmission electron microscopy, X-ray diffraction, UV-Vis, Dynamic light scattering, Fourier transform infrared, and Energy-dispersive X-ray spectroscopy. Furthermore, in vitro studies were also performed to evaluate NPs cytotoxic profile and antifungal activity. The results obtained revealed that the produced nanoparticles are biocompatible and have a good potential for being used in the treatment of common skin infections caused by Trichophyton rubrum and Trichophyton mentagrophytes, being PVP-coated silver NPs the most suitable ones.

Resistive switching effect of N-doped MoS2-PVP nanocomposites films for nonvolatile memory devices

Science.gov (United States)

Wu, Zijin; Wang, Tongtong; Sun, Changqi; Liu, Peitao; Xia, Baorui; Zhang, Jingyan; Liu, Yonggang; Gao, Daqiang

2017-12-01

Resistive memory technology is very promising in the field of semiconductor memory devices. According to Liu et al, MoS2-PVP nanocomposite can be used as an active layer material for resistive memory devices due to its bipolar resistive switching behavior. Recent studies have also indicated that the doping of N element can reduce the band gap of MoS2 nanosheets, which is conducive to improving the conductivity of the material. Therefore, in this paper, we prepared N-doped MoS2 nanosheets and then fabricated N-doped MoS2-PVP nanocomposite films by spin coating. Finally, the resistive memory [C. Tan et al., Chem. Soc. Rev. 44, 2615 (2015)], device with ITO/N-doped MoS2-PVP/Pt structure was fabricated. Study on the I-V characteristics shows that the device has excellent resistance switching effect. It is worth mentioning that our device possesses a threshold voltage of 0.75 V, which is much better than 3.5 V reported previously for the undoped counterparts. The above research shows that N-doped MoS2-PVP nanocomposite films can be used as the active layer of resistive switching memory devices, and will make the devices have better performance.

Synthesis and in-vivo evaluation of C-11 p-PVP-MEMA as a PET radioligand for imaging nicotinic receptors

International Nuclear Information System (INIS)

Paine, T.; Kassiou, M.; Dolle, F.; Langle, S.; Roger, G.; Lagnel-de Bruin, B.; Hinnen, F.; Valette, H.; Bottlaender, M.; Fulton, R.R.; Henderson, D.J.; Coster, M.J.; Kassiou, M.

2008-01-01

Within the class of (4-pyridinyl)vinyl-pyridines developed by Abbott laboratories as potent neuronal nicotinic acetylcholine receptor ligands, p-PVP-MEMA ({oro-5-((E)-2-pyridin-4-yl-vinyl) pyridin-3-yloxy]-1-methylethyl} is the lead compound of a novel series that do not display the traditional nicotinic-like pyrrole-ring but still possessing high sub-nanomolar affinity (K-i 0.077 nm-displacement of [H-3](-)cytisine from whole rat brain synaptic membranes). In the present study, p-PVP-MEMA and its nor-derivative ({oro-5-((E)-2-pyridin-4- yl-vinyl) pyridin-3-yloxy]-1-methylethyl} as precursor for labelling with the short-lived positron-emitter carbon-11 (T 1/2 = 20.4 min) were synthesized in 10 chemical steps from 2-hydroxy-5-nitropyridine and Boc-D-alanine. N-Alkylation of nor-p-PVP-MEMA with [C-11] methyl iodide afforded [C-11]p-PVP-MEMA (≥ 98% radiochemically pure, specific activity of 86.4 GBq μ mol -1 ) in 2% (non-decay corrected and non-optimized) radiochemical yield, in 34 min (including HPLC purification and formulation). Preliminary positron emission tomography PET) results obtained in a Papio hamadryas baboon showed that [C-11] p-PVP-MEMA is not a suitable PET-radioligand. (authors)

Enhancement in in vitro anti-angiogenesis activity and cytotoxicity in lung cancer cell by pectin-PVP based curcumin particulates.

Science.gov (United States)

Gaikwad, Dinanath; Shewale, Rajnita; Patil, Vinit; Mali, Dipak; Gaikwad, Uday; Jadhav, Namdeo

2017-11-01

The aim of this work was to prepare pectin-poly (vinyl pyrrolidone) [PVP] based curcumin particulates to enhance the anticancer potential of curcumin, solubility and allow its localized controlled release. Pectin-PVP based curcumin particulates (PECTIN-PVP CUR) were prepared by spray drying technique in different ratios and were evaluated for surface morphology, micromeritics, flowability, particle size, drug content, in vitro dissolution, inhalable fraction, anti-angiogenesis/angiolysis and cytotoxicity. Results of micromeritic properties, Carr's index, Hausner's ratio and angle of repose were satisfactory. The batch CP3 was considered as optimum, due to excellent flowability, acceptable aggregation and enhanced solubility. The particle size and size distribution data of selected batch CP3 showed 90% of curcumin particulates having size less than 2.74μm, which may deposit to lungs. Twin Impinger studies showed that 29% of respirable fraction was generated, which could be directly delivered to lungs. The in vitro dissolution data showed many fold increase in dissolution rate. Angiolytic activity and MTT assay of PECTIN-PVP CUR have demonstrated enhancement in the anti-tumor potential, compared to curcumin alone. Altogether, PECTIN-PVP CUR were found suitable for local delivery and enhance its anticancer potential of curcumin. Copyright © 2017 Elsevier B.V. All rights reserved.

Synthesis and characterization of PVP/ Sb2S3 composite films

International Nuclear Information System (INIS)

Salema, A.M.; Marzouka, S.; Khafagib, M.G.

2005-01-01

Polyvinyl pyrrolidone has been successfully used as a matrix to embedded Sb 2 S 3 nanoparticles. PVP thin films containing 5-25 wt % Sb 2 S 3 were deposited onto glass substrates by dip coating. X-ray diffraction spectra revealed that Sb 2 S 3 crystals depressed as nanometer-sized in the PVP matrix and the result was confirmed via scanning electron microscopy. The transmission and reflection spectra of the prepared samples were recorded in the wavelength optical range 250-2500 nm. The transmission spectra of the films show that transmission valley shifts toward higher wavelengths with increasing Sb 2 S 3 wt %. The optical constants of the deposited films, such as refractive index, extinction coefficient were obtained using the transmission and reflection data. The spectral behaviour of the loss factor, as well as the real and imaginary parts of the optical conductivity were also presented

Physicochemical properties of direct compression tablets with spray dried and ball milled solid dispersions of tadalafil in PVP-VA.

Science.gov (United States)

Wlodarski, K; Tajber, L; Sawicki, W

2016-12-01

The aim of this research was to develop immediate release tablets comprising solid dispersion (IRSDTs) of tadalafil (Td) in a vinylpyrrolidone and vinyl acetate block copolymer (PVP-VA), characterized by improved dissolution profiles. The solid dispersion of Td in PVP-VA (Td/PVP-VA) in a weight ratio of 1:1 (w/w) was prepared using two different processes i.e. spray drying and ball milling. While the former process has been well established in the formulation of IRSDTs the latter has not been exploited in these systems yet. Regardless of the preparation method, both Td/PVP-VA solid dispersions were amorphous as confirmed by PXRD, DSC and FTIR. However, different morphology of particles (SEM) resulted in differences in water apparent solubility and disk intrinsic dissolution rate (DIDR). Both solid dispersions and crystalline Td were successfully made into directly compressible tablets at three doses of Td, i.e. 2.5mg, 10mgand20mg, yielding nine different formulations (D 1 -D 9 ). Each of the lots met the requirements set by Ph.Eur. and was evaluated with respect to appearance, diameter, thickness, mass, hardness, friability, disintegration time and content of Td. IRSDTs performed as supersaturable formulations and had significantly improved water dissolution profiles in comparison with equivalent tablets containing crystalline Td and the marketed formulations. Tablets with both spray dried and ball milled Td/PVP-VA revealed the greatest improvement in dissolution depending on the investigated doses, i.e. 2.5mgand20mg, respectively. Also, dissolution of Td from Td/PVP-VA delivered in different forms occurred in the following order: powders>tablets>capsules. Copyright © 2016 Elsevier B.V. All rights reserved.

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

International Nuclear Information System (INIS)

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

2017-01-01

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 (TiO 2 )/polyvinylpyyrolidone (PVP) onto a polyvinyl chloride (PVC) film surface via the direct-current glow discharge plasma method. To enhance the chemical interaction between TiO 2 /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, TiO 2 /PVP were grafted using a simple dip-coating method. In addition, the TiO 2 /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, TiO 2 /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 TiO 2 /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 TiO 2 /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 TiO 2 /PVP-grafted film is also greatly improved compared with an air- and argon

Synthesis and in-vivo evaluation of C-11 p-PVP-MEMA as a PET radioligand for imaging nicotinic receptors

Energy Technology Data Exchange (ETDEWEB)

Paine, T.; Kassiou, M. [Univ Sydney, Sch Chem, Sydney, NSW 2006 (Australia); Dolle, F.; Langle, S.; Roger, G.; Lagnel-de Bruin, B.; Hinnen, F.; Valette, H.; Bottlaender, M. [CEA, Serv Hosp Frederic Joliot, Inst Imagerie Biomed, F-91401 Orsay (France); Fulton, R.R.; Henderson, D.J. [Royal Prince Alfred Hosp, Dept PET and Nucl Med, Camperdown, NSW 2050 (Australia); Coster, M.J. [Griffith Univ, Eskitis Inst Cell and Mol Therapies, Nathan, Qld 4121 (Australia); Kassiou, M. [Univ Sydney, Discipline Med Radiat Sci, Sydney, NSW2006 (Australia); Brain and Mind Res Inst, Camperdown, NSW2050 (Australia)

2008-07-01

Within the class of (4-pyridinyl)vinyl-pyridines developed by Abbott laboratories as potent neuronal nicotinic acetylcholine receptor ligands, p-PVP-MEMA ({l_brace}oro-5-((E)-2-pyridin-4-yl-vinyl) pyridin-3-yloxy]-1-methylethyl{r_brace} is the lead compound of a novel series that do not display the traditional nicotinic-like pyrrole-ring but still possessing high sub-nanomolar affinity (K-i 0.077 nm-displacement of [H-3](-)cytisine from whole rat brain synaptic membranes). In the present study, p-PVP-MEMA and its nor-derivative ({l_brace}oro-5-((E)-2-pyridin-4- yl-vinyl) pyridin-3-yloxy]-1-methylethyl{r_brace} as precursor for labelling with the short-lived positron-emitter carbon-11 (T{sub 1/2} = 20.4 min) were synthesized in 10 chemical steps from 2-hydroxy-5-nitropyridine and Boc-D-alanine. N-Alkylation of nor-p-PVP-MEMA with [C-11] methyl iodide afforded [C-11]p-PVP-MEMA ({>=} 98% radiochemically pure, specific activity of 86.4 GBq {mu} mol{sup -1}) in 2% (non-decay corrected and non-optimized) radiochemical yield, in 34 min (including HPLC purification and formulation). Preliminary positron emission tomography PET) results obtained in a Papio hamadryas baboon showed that [C-11] p-PVP-MEMA is not a suitable PET-radioligand. (authors)

OligoPVP: Phenotype-driven analysis of individual genomic information to prioritize oligogenic disease variants

KAUST Repository

Boudellioua, Imene

2018-05-02

Purpose: An increasing number of Mendelian disorders have been identified for which two or more variants in one or more genes are required to cause the disease, or significantly modify its severity or phenotype. It is difficult to discover such interactions using existing approaches. The purpose of our work is to develop and evaluate a system that can identify combinations of variants underlying oligogenic diseases in individual whole exome or whole genome sequences. Methods: Information that links patient phenotypes to databases of gene-phenotype associations observed in clinical research can provide useful information and improve variant prioritization for Mendelian diseases. Additionally, background knowledge about interactions between genes can be utilized to guide and restrict the selection of candidate disease modules. Results: We developed OligoPVP, an algorithm that can be used to identify variants in oligogenic diseases and their interactions, using whole exome or whole genome sequences together with patient phenotypes as input. We demonstrate that OligoPVP has significantly improved performance when compared to state of the art pathogenicity detection methods. Conclusions: Our results show that OligoPVP can efficiently detect oligogenic interactions using a phenotype-driven approach and identify etiologically important variants in whole genomes.

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

CSIR Research Space (South Africa)

Labuschagne, Philip W

2010-06-01

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

Pd/Co bimetallic nanoparticles: coelectrodeposition under protection of PVP and enhanced electrocatalytic activity for ethanol electrooxidation

Energy Technology Data Exchange (ETDEWEB)

Yang, Z.S.; Wu, J.J. [College of Chemistry and Materials Science, Anhui Key Laboratory of Chemo-Biosensing, Anhui Normal University, Wuhu 241000 (China)

2012-06-15

A series of Pd-Co bimetallic nanostructures with Co compositions ranging from 0 to 13 at.% were fabricated on glassy carbon electrode by one step electrodeposition in the presence of polyvinylpyrrolidone (PVP). The roles of PVP and Co have been systematically investigated by using combined techniques such as scanning electron microscopy, energy dispersive spectrometry, cyclic voltammetry, X-ray diffraction, and chronoamperograms. PVP was used as an additive to stabilize the Pd nanoparticles and inhibit agglomeration during their formation. The prepared Pd{sub 100}Co{sub 10} bimetallic nanostructures exhibited great catalytic activity towards ethanol oxidation in alkaline, which implies that low Co doping can be a convenient way to enhance the electrocatalytic property of Pd. The present study shows that the Pd/Co bimetallic nanoparticulate can be a promising catalyst for portable applications in direct ethanol fuel cell in alkaline solution. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Peningkatan Laju Disolusi Dispersi Padat Amorf Genistein dengan PVP K-30

Directory of Open Access Journals (Sweden)

Erizal Zaini

2017-12-01

Full Text Available Amorphous solid dispersions of a poorly water-soluble drug genistein in PVP K-30 were prepared by solvent co-evaporation technique using organic solvent methanol. Solid dispersions system was prepared with several variations of drug to polymer 2:1, 1:1 dan 1:2 w/w. Solid state properties of solid dispersion system were evaluated by powder X-ray diffraction, Fourier transform infrared spectroscopy, and differential scanning calorimetry, and microscopic SEM. Dissolution rate profile were conducted in distilled water medium by using dissolution tester apparatus type II USP. Base on X-ray diffractometry analysis, differential scanning calorimetry and microscopic SEM, crystalline phase of genistein decreased in crystallinity index and formation of amophous state. Dissolution rate profile showed that genistein in amorphous solid dispersion had a faster dissolution rate in comparison to intact genistein. This study proved that preparation of solid dispersion of genistein in PVP K-30 is an effective approach to improve dissolution rate of genistein.

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

Directory of Open Access Journals (Sweden)

Caroline Pires Ruas

2013-01-01

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

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

Science.gov (United States)

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.

Partially decomposed PVP as a surface modification of ZnO, CdO ...

Indian Academy of Sciences (India)

2017-06-10

Jun 10, 2017 ... of oxygen with PVP to capsulate metal oxides during the synthesis. Infrared .... to prepare PVP–CdS nanoparticles [19] and here we extend it to prepare ZnS, .... ZnS by a microwave–hydrothermal method and obtained band.

SERS studies on the interaction between UO22+ and PVP-stabilized silver nanoparticles

International Nuclear Information System (INIS)

Roy, M.; Tyagi, A.K.; Kumar, Rakesh; Pandey, A.K.; Goswami, A.

2010-01-01

Interaction between uranyl (UO 2 2+ ) ions and silver nanoparticles (Ag-nps) stabilized by suitable polymeric capping agents has been studied in aqueous phase using surface enhanced resonance Raman spectroscopy technique (SERS). Polyvinylpyrrolidone (PVP) stabilized Ag-nps were synthesized by dissolving in water appropriate amount of PVP and AgNO 3 along with a suitable reducing agent in the form of either formamide or sodium borohydride. The solution was vigorously stirred for 5h and finally nanoparticle sols were obtained. A series of analyte samples was prepared by adding an appropriate amount of silver sol to different volumes of uranyl stock solution prepared at pH=3. The solutions were then drop cast on glass slides and dried in air. Preliminary results on drop-cast samples are presented here

Synthesis of Polyvinyl Pirrolidone (PVC /Κ-Carrageenan Hydrogel Prepared by Gamma Radiation Processing As a Function of Dose and PVP Concentration

Directory of Open Access Journals (Sweden)

Erizal Erizal

2013-05-01

Full Text Available The aim of this research is to prepare a biomaterial to be used in health care. A series of hydrogels based on polyvinyl pyrrolidone (PVP/κ-Carrageenan (KC has been prepared by radiation technique. PVP (5-15% were mixed with ΚC (2% and irradiated by gamma rays at the doses from 25 kGy to 35 kGy (dose rate 7 kGy/h at room temperature. The chemical change of hydrogels was characterized using Fourier Transform infra Red (FTIR. Gel fraction, water absorption and water evaporation were determined gravimetrically. Tensile strength and elongation at break was measured using Instron meter. It was found that with the increase irradiation dose and PVP concentration, the gel fraction and tensile strength of hydrogels increase. In contrast the elongation at break and water absorption of hydrogels decrease. The hydrogel of PVP/KC hydrogel produced by gamma radiation can be considered for wound dressings.

Molecular motions in sucrose-PVP and sucrose-sorbitol dispersions-II. Implications of annealing on secondary relaxations.

Science.gov (United States)

Bhattacharya, Sisir; Bhardwaj, Sunny P; Suryanarayanan, Raj

2014-10-01

To determine the effect of annealing on the two secondary relaxations in amorphous sucrose and in sucrose solid dispersions. Sucrose was co-lyophilized with either PVP or sorbitol, annealed for different time periods and analyzed by dielectric spectroscopy. In an earlier investigation, we had documented the effect of PVP and sorbitol on the primary and the two secondary relaxations in amorphous sucrose solid dispersions (1). Here we investigated the effect of annealing on local motions, both in amorphous sucrose and in the dispersions. The average relaxation time of the local motion (irrespective of origin) in sucrose, decreased upon annealing. However, the heterogeneity in relaxation time distribution as well as the dielectric strength decreased only for β1- (the slower relaxation) but not for β2-relaxations. The effect of annealing on β2-relaxation times was neutralized by sorbitol while PVP negated the effect of annealing on both β1- and β2-relaxations. An increase in local mobility of sucrose brought about by annealing could be negated with an additive.

Organic-inorganic Au/PVP/ZnO/Si/Al semiconductor heterojunction characteristics

Science.gov (United States)

Mokhtari, H.; Benhaliliba, M.

2017-11-01

The paper reports the fabrication and characterization of a novel Au/PVP/ZnO/Si/Al semiconductor heterojunction (HJ) diode. Both inorganic n type ZnO and organic polyvinyl pyrrolidone (PVP) layers have grown by sol-gel spin-coating route at 2000 rpm. The front and back metallic contacts are thermally evaporated in a vacuum at pressure of 10-6 Torr having a diameter of 1.5 mm and a thickness of 250 nm. The detailed analysis of the forward and reverse bias current-voltage characteristics has been provided. Consequently, many electronic parameters, such as ideality factor, rectification coefficient, carrier concentration, series resistance, are then extracted. Based upon our results a non-ideal diode behavior is revealed and ideality factor exceeds the unity (n > 4). A high rectifying (~4.6 × 10 4) device is demonstrated. According to Cheung-Cheung and Norde calculation models, the barrier height and series resitance are respectively of 0.57 eV and 30 kΩ. Ohmic and space charge limited current (SCLC) conduction mechanisms are demonstrated. Such devices will find applications as solar cell, photodiode and photoconductor.

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

Science.gov (United States)

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

2015-09-01

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

Nonlinear optical properties of Nd3+-Li+ co-doped ZnS-PVP thin films

Science.gov (United States)

Talwatkar, S. S.; Sunatkari, A. L.; Tamgadge, Y. S.; Muley, G. G.

2018-04-01

The nonlinear optical properties of Nd3+-Li+ co-doped ZnS-PVP nanocomposite were studied using a continuous wave (CW) He-Ne laser (λ = 632.8 nm)by z-scan technique. The nonlinear refractive index (n2), absorption coefficient (β) and third order nonlinear susceptibility (χ(3)) of PVP thin films embedded with Nd3+-Li+ co-doped ZnS NPs was found in the order of 10-7 cm2/W, 10-6 cm/W and 10-7 esu respectively. The nonlinearity found increasing with Nd3+-Li+ co-dopant concentration. Based on the results, it is proposed that this material is a new class of luminescent material suitable in optoelectronics devices application, especially in light-emitting devices, electroluminescent devices, display devices, etc.

Effect of PVP Intermediate Layer on the Properties of SAPO 34 Membrane

Directory of Open Access Journals (Sweden)

Jugal K. Das

2012-01-01

Full Text Available SAPO 34 zeolite membranes were prepared on a tubular mullite support. Before membrane preparation, the support surfaces were coated with seed crystals. Seeds particles were prepared by hydrothermal synthesis. Before seeding, the substrates were treated with polyvinylpyrrolidone (PVP to orient the seeds. Both the treated and untreated supports were seeded, and membranes were synthesized on those support tubes by ex situ hydrothermal method. The PVP molecule exists in the two resonance structures. Hence the acylamino bond –N+ = C–O-– acts as intermediate linker between support surface and seed surface. Due to charge interaction, the seed crystals were anchored strongly to support surface. The synthesized membranes along with seed crystals were characterized by XRD, FESEM, and EDAX analysis. The single-gas permeation with CO2 and H2 was investigated. Up to 5 bar of feed pressure, the permselectivity of CO2 and H2 was as high as 4.2.

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

International Nuclear Information System (INIS)

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

2014-01-01

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

Rapid and sensitive detection of synthetic cannabinoids AMB-FUBINACA and α-PVP using surface enhanced Raman scattering (SERS)

Science.gov (United States)

Islam, Syed K.; Cheng, Yin Pak; Birke, Ronald L.; Green, Omar; Kubic, Thomas; Lombardi, John R.

2018-04-01

The application of surface enhanced Raman scattering (SERS) has been reported as a fast and sensitive analytical method in the trace detection of the two most commonly known synthetic cannabinoids AMB-FUBINACA and alpha-pyrrolidinovalerophenone (α-PVP). FUBINACA and α-PVP are two of the most dangerous synthetic cannabinoids which have been reported to cause numerous deaths in the United States. While instruments such as GC-MS, LC-MS have been traditionally recognized as analytical tools for the detection of these synthetic drugs, SERS has been recently gaining ground in the analysis of these synthetic drugs due to its sensitivity in trace analysis and its effectiveness as a rapid method of detection. This present study shows the limit of detection of a concentration as low as picomolar for AMB-FUBINACA while for α-PVP, the limit of detection is in nanomolar concentration using SERS.

Study of surface-modified PVP gate dielectric in organic thin film transistors with the nano-particle silver ink source/drain electrode.

Science.gov (United States)

Yun, Ho-Jin; Ham, Yong-Hyun; Shin, Hong-Sik; Jeong, Kwang-Seok; Park, Jeong-Gyu; Choi, Deuk-Sung; Lee, Ga-Won

2011-07-01

We have fabricated the flexible pentacene based organic thin film transistors (OTFTs) with formulated poly[4-vinylphenol] (PVP) gate dielectrics treated by CF4/O2 plasma on poly[ethersulfones] (PES) substrate. The solution of gate dielectrics is made by adding methylated poly[melamine-co-formaldehyde] (MMF) to PVP. The PVP gate dielectric layer was cross linked at 90 degrees under UV ozone exposure. Source/drain electrodes are formed by micro contact printing (MCP) method using nano particle silver ink for the purposes of low cost and high throughput. The optimized OTFT shows the device performance with field effect mobility of the 0.88 cm2/V s, subthreshold slope of 2.2 V/decade, and on/off current ratios of 1.8 x 10(-6) at -40 V gate bias. We found that hydrophobic PVP gate dielectric surface can influence on the initial film morphologies of pentacene making dense, which is more important for high performance OTFTs than large grain size. Moreover, hydrophobic gate dielelctric surface reduces voids and -OH groups that interrupt the carrier transport in OTFTs.

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

International Nuclear Information System (INIS)

Silva, Andressa A.; Leal, Jessica; Geraldes, Adriana N.; Lugao, Ademar B.

2015-01-01

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

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

Energy Technology Data Exchange (ETDEWEB)

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

2015-07-01

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

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

Energy Technology Data Exchange (ETDEWEB)

Hemalatha, K.; Gowtham, G. K.; Somashekarappa, H., E-mail: drhssappa@gmail.com [Department of Physics, Yuvaraja’s College, University of Mysore, Mysore 570 005, Karnataka (India); Mahadevaiah,; Urs, G. Thejas; Somashekar, R. [Department of Studies in Material Sciences, University of Mysore, Mysore 570 006, Karnataka (India)

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.

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

Science.gov (United States)

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.

Preparation and in-vitro in-vivo evaluation of sustained release matrix diclofenac sodium tablets using PVP-K90 and natural gums.

Science.gov (United States)

Iqbal, Zafar; Khan, Raza; Nasir, Fazli; Khan, Jamshaid Ali; Rashid, Abdur; Khan, Abbas; Khan, Abad

2011-10-01

Conventional dosage form is nowadays mostly replaced by sustained release formulation in order to increase drug efficacy and patient compliance. The sustained release properties of the PVP K90 alone and in combination with guar gum, xanthan gum and gum tragacanth were evaluated using diclofenac sodium (100 mg/tablet) as a model drug. Tablets were processed using wet granulation method and evaluated for sustained drug release properties. The drug release from the formulations was studied in relationship with Commercially available Diclofenac Sodium SR, used as a reference tablets and results were expressed as similarity (f1) and differential factor (f2). The tablets prepared using PVP K90 160 mg/tablet sustained the release of diclofenac sodium for 12 hours. Formulations where the PVP K90 was partially replaced with different gums also sustained the release of drug for 12 hours. The release of the drug from these formulations mainly followed Higuchi model and super case-II and Non-Fickian diffusion. The in-vivo drug release was studied in healthy human volunteers using non-blinded cross over, two period design using Diclofenac Sodium SR Tablets as a reference drug. The relative bioavailability of the formulation containing PVP K90 and gum tragacanth was 0.91. The studies showed that the use of the PVP K90 in combination with gum tragacanth both in-vitro and in-vivo sustained the release of the drug.

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.

Science.gov (United States)

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.

Red light emitting nano-PVP fibers that hybrid with Ag@SiO2@Eu(tta)3phen-NPs by electrostatic spinning method

Science.gov (United States)

Zhang, Xiaolin; Tang, Jianguo; Li, Haidong; Wang, Yao; Wang, Xinzhi; Wang, Yanxin; Huang, Linjun; Belfiore, Laurence A.

2018-04-01

This work demonstrated red light emitting nano-PVP fibers that incorporated with novel three-layer nanostructure of Ag@SiO2@Eu(tta)3phen nanoparticles (Ag@SiO2@Eu(tta)3phen-NPs), and the hybrid nano-PVP fibers were fabricated via a remarkably simple electrostatic spinning method. For Ag@SiO2@Eu(tta)3phen-NPs, the thickness of SiO2 is optimized to obtain the maximum luminescent intensity, as results, the optimized thickness of SiO2 is 20 nm. And the corresponding luminescent intensity (612 nm) of the Ag@SiO2@Eu(tta)3phen-NPs is enhanced up to 10 times compared with the pure Eu(tta)3phen complex, which indicates that with 20 nm SiO2 thickness, the localized surface plasmon resonance (LSPR) effect of Ag@SiO2 exhibits highest performance for enhancing luminescence. Moreover, the luminescent PVP fibers emit bright red light under the fluorescence microscope, which definitely confirms that the microenvironment provided by PVP polymer is absolutely suitable for the fluorescent composites.

Kinetic and theoretical studies of novel biodegradable thermo-sensitive xerogels based on PEG/PVP/silica for sustained release of enrofloxacin

Science.gov (United States)

Ebadi, Azra; Rafati, Amir Abbas; Bavafa, Sadeghali; Mohammadi, Masoumah

2017-12-01

This study involves the synthesis of a new silica-based colloidal hybrid system. In this new hybrid system, poly (ethylene glycol) (PEG) and thermo-sensitive amphiphilic biocompatible poly (vinyl pyrrolidone) (PVP) were used to create suitable storage for hydrophobic drugs. The possibility of using variable PVP/PEG molar ratios to modulate drug release rate from silica nanoparticles was a primary goal of the current research. In addition, an investigation of the drug release kinetic was conducted. To achieve this, silica nanoparticles were synthesized in poly (ethylene glycol) (PEG) and poly (vinyl pyrrolidone) (PVP) solution incorporated with enrofloxacin (EFX) (as a model hydrophobic drug), using a simple synthetic strategy of hybrid materials which avoided waste and multi-step processes. The impacts of PVP/PEG molar ratios, temperature, and pH of the release medium on release kinetic were investigated. The physicochemical properties of the drug-loaded composites were studied by Fourier transform infrared (FT-IR) spectra, scanning electron microscopy (SEM), and thermogravimetric analysis (TGA). In vitro drug release studies demonstrated that the drug release rate, which was evaluated by analyzing the experimental data with seven kinetic models in a primarily non-Fickian diffusion-controlled process, aligned well with both Ritger-Peppas and Sahlin-Peppas equations.

Characterization and improvement of PVAl/PVP/PEG hydrogels

International Nuclear Information System (INIS)

Oliveira, Maria Jose A.; Parra, Duclerc F.; Almeida, Monise F.; Lugao, Ademar B.

2009-01-01

The use of hydrogels matrices for particular drug release applications has been investigated with the synthesis of modified polymeric hydrogel of poly (vinyl alcohol) (PVAl), poly (N-vinyl-2-pyrrolidone) (PVP) and poly (ethylene glycol). They were processed using gamma radiation from Cobalt-60 source at 25 kGy dose. In this study it was compared the hydrogels reticulation for irradiation gamma O 2 and N 2 atmosphere. The characterization of the hydrogels was conducted and the toxicity was evaluated. The dried hydrogel was analyzed by differential scanning calorimetry (DSC), thermogravimetry (TGA), swelling and gel determinations. The membranes have no toxicity and gel content revealed the crosslinking degree. (author)

Microwave-irradiation polyol synthesis of PVP-protected Pt–Ni electrocatalysts for methanol oxidation reaction

CSIR Research Space (South Africa)

Mathe, Ntombizodwa R

2017-01-01

Full Text Available ://doi.org/10.1007/s12678-017-0441-3 Microwave-Irradiation Polyol Synthesis of PVP-Protected Pt–Ni Electrocatalysts for Methanol Oxidation Reaction Ntombizodwa R. Mathe Manfred R. Scriba Rirhandzu S. Rikhotso Neil J. Coville ABSTRACT: Bimetallic Pt...

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

Energy Technology Data Exchange (ETDEWEB)

Ahmad, H.A. [Department of Physics, Faculty of Science, Universiti Putra Malaysia, UPM, 43400 Serdang, Selangor (Malaysia); Saiden, N.M., E-mail: nlaily@upm.edu.my [Department of Physics, Faculty of Science, Universiti Putra Malaysia, UPM, 43400 Serdang, Selangor (Malaysia); Saion, E.; Azis, R.S.; Mamat, M.S. [Department of Physics, Faculty of Science, Universiti Putra Malaysia, UPM, 43400 Serdang, Selangor (Malaysia); Hashim, M. [Advanced Material and Nanotechnology Laboratory, Institute of Advanced Technology, Universiti Putra Malaysia, UPM, 43400 Serdang, Selangor (Malaysia)

2017-04-15

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, H{sub c} and saturation magnetization, M{sub s} 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, Ni{sub 0.5}Zn{sub 0.5}Fe{sub 2}O{sub 4} and SrFe{sub 12}O{sub 19} 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 H{sub c} 932 G and M{sub s} 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. - Highlights: • Amount of PVP play important roles in controlling the particle size distribution and magnetic properties. • This is a novel technique to produce nanocomposite ferrites effectively. • This study contributes better understanding on magnetic properties in nanoparticle composite magnets.

Formation Mechanism and Dispersion of Pseudo-Tetragonal BaTiO3-PVP Nanoparticles from Different Titanium Precursors: TiCl4 and TiO2

Directory of Open Access Journals (Sweden)

Jinhui Li

2017-12-01

Full Text Available Nano-sized tetragonal BaTiO3 (BT particles that are well dispersed in solution are essential for the dielectric layer in multilayer ceramic capacitor technology. A hydrothermal process using TiCl4 and BaCl2, as source of Ti and Ba, respectively, or the precursor TiO2 as seed for the formation of BT, and poly(vinylpyrrolidone (PVP as a surfactant, was employed in this study to enhance both the dispersibility and tetragonality (c/a simultaneously in a single reaction process. The process parameters, i.e., the ratio of TiO2 substitution of TiCl4, the reaction time, and PVP content were systematically studied, and the growth mechanism and relation between the tetragonality and the particle size are discussed. Dynamic light scattering (DLS analysis was used to show that truncated pseudo-tetragonal BT-PVP particles with an average size of 100 nm, having a narrow size distribution and a coefficient of variation (CV as low as 20% and being mono-dispersed in water, were produced. The narrow particle size distribution is attributed to the ability of PVP to inhibit the growth of BT particles, and the high c/a of BT-PVP to heterogeneous particle growth using TiO2 seeds.

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

OpenAIRE

Somashekarappa, H.; Prakash, Y.; Hemalatha, K.; Demappa, T.; Somashekar, R.

2013-01-01

The aim of this present work is to investigate the effect of plasticizers like Sorbitol on microstructural and mechanical properties of hydroxypropyl methylcellulose (HPMC) and Polyvinylpyrrolidone (PVP) blend films. The pure blend and plasticized blend films were prepared by solution casting method and investigated using wide angle X-ray scattering (WAXS) method. WAXS analysis confirms that the plasticizers can enter into macromolecular blend structure and destroy the crystallinity of the f...

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

Energy Technology Data Exchange (ETDEWEB)

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

2009-07-01

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

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

International Nuclear Information System (INIS)

Alcantara, Mara Tania S.; Lugao, Ademar B.; Taqueda, Maria Elena S.

2009-01-01

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

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

Science.gov (United States)

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

1986-08-01

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

Optical absorption studies on biodegradable PVA/PVP blend polymer electrolyte system

Science.gov (United States)

Basha, S. K. Shahenoor; Reddy, K. Veera Bhadra; Rao, M. C.

2018-05-01

Biodegradable blend polymer electrolytes of PVA/PVP with different wt% ratios of MgCl2.6H2O have been prepared using solution cast technique. Optical absorption studies were carried-out on to the prepared films at room temperature using JASCO V-670 Spectrophotometer in the wavelength region 200-600 nm. Due to the clusters between the vibrations of molecules a broad peak is obtained due to п-п* transition in the wavelength region 310-340 nm.

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

KAUST Repository

Huang, Jonathan P.

2012-04-11

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

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

KAUST Repository

Huang, Jonathan P.; Mojib, Nazia; Goli, Rakesh R.; Watkins, Samantha; Waites, Ken B.; Ravindra, Rasik; Andersen, Dale T.; Bej, Asim K.

2012-01-01

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

The effect of minimal concentration of ethylene glycol (EG) combined with polyvinylpyrrolidone (PVP) on mouse oocyte survival and subsequent embryonic development following vitrification.

Science.gov (United States)

Wang, Yao; Okitsu, Osamu; Zhao, Xiao-Ming; Sun, Yun; Di, Wen; Chian, Ri-Cheng

2014-01-01

Vitrification techniques employ a relatively high concentration of cryoprotectant in vitrification solutions. Exposure of oocytes to high concentrations of cryoprotectant is known to damage the oocytes via both cytotoxic and osmotic effects. Therefore, the key to successful vitrification of oocytes is to strike a balance between the usage of minimal concentration of cryoprotectant without compromising their cryoprotective actions. The minimal concentration of ethylene glycol (EG) on mouse oocyte survival and subsequent embryonic development was evaluated following vitrification-warming and parthenogenetic activation. Polyvinylpyrrolidone (PVP) combined with EG on mouse oocyte survival and subsequent embryonic development as well as morphology of the spindle and chromosome alignment were also evaluated. Vitrification system was adapted with JY Straw and the cooling rate was approximately 442-500 °C/min. In contrast, the warming rate was approximately 2,210-2,652 °C/min. Survival rate of oocytes increased significantly when 15 % EG was combined with 2 % PVP in vitrification solution (VS). The effect of combination of EG and PVP was not significant when the concentration of EG was 20 % and higher. Although there were no significant differences in embryonic development, the percentage of abnormal spindle and chromosome alignment was significantly higher in the oocytes without 2 % PVP in VS. Our data provide a proof of principle for oocyte vitrification that may not require a high concentration of cryoprotectant. There are synergic effects of EG combined with PVP for oocyte vitrification, which may provide important information to the field in developing less cytotoxic VS.

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

DEFF Research Database (Denmark)

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

2008-01-01

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

Characterization of electron beam irradiated collagen-polyvinylpyrrolidone (PVP) and collagen-dextran (DEX) blends

International Nuclear Information System (INIS)

Dumitrascu, M.; Sima, E.; Minea, R.; Vancea, C.; Meltze, V.; Albu, M.G.

2011-01-01

Complete text of publication follows. The aim of the present study was to investigate the influence of electron beam irradiation on some blends of collagen-polyvinylpyrrolidone (PVP) and collagen-dextran (DEX). The blends were prepared by mixing different quantities of collagen, PVP and DEX in distilled water. After irradiation the obtained hydrogels were processed by controlled drying and freeze-drying. Both types of materials were characterized by FT-IR, FT-Raman, TG, DSC, water uptake and SEM. The intensity of the characteristic bands, in the range 2800-3600 cm -1 from FT-IR spectra, varied considerably as function of absorbed radiation dose. Raman spectra revealed the absence of the characteristic peak at 2700 cm -1 for irradiated blends at 30 kGy. Kinetic parameters were calculated from the TG, DTG and DSC data by means of isoconversion methods at different heating rates. Thereby a relation between absorbed radiation dose and activation energy was established. Water uptake studies were carried out in PBS solution (phosphate buffer saline) at 37 deg C and pH = 7.4 and the results revealed a decrease of the water uptake with increasing of absorbed radiation dose.

Effects of a Thin Ru-Doped PVP Interface Layer on Electrical Behavior of Ag/n-Si Structures

Science.gov (United States)

Badali, Yosef; Nikravan, Afsoun; Altındal, Şemsettin; Uslu, İbrahim

2018-03-01

The aim of this study is to improve the electrical property of Ag/n-Si metal-semiconductor (MS) structure by growing an Ru-doped PVP interlayer between Ag and n-Si using electrospinning technique. To illustrate the utility of the Ru-doped PVP interface layer, current-voltage (I-V) characteristics of Ag/n-Si (MS) and Ag/Ru-doped PVP/n-Si metal-polymer-semiconductor (MPS) structures was carried out. In addition, the main electrical parameters of the fabricated Ag/Ru-doped PVP/n-Si structures were investigated as a function of frequency and electric field using impedance spectroscopy method (ISM). The capacitance-voltage (C-V) plot showed an anomalous peak in the depletion region due to the special density distribution of interface traps/states (D it /N ss) and interlayer. Both the values of series resistance (R s) and N ss were drawn as a function of voltage and frequency between 0.5 kHz and 5 MHz at room temperature and they had a peak behavior in the depletion region. Some important parameters of the sample such as the donor concentration atoms (N D), Fermi energy (E F ), thickness of the depletion region (W D), barrier height (Φ B0 ) and R s were determined from the C -2 versus V plot for each frequency. The values of N D , W D , Φ B0 and R s were changed from 1 × 1015 cm-3, 9.61 × 10-5 cm, 0.94 eV and 19,055 Ω (at 0.5 kHz) to 0.13 × 1015 cm-3, 27.4 × 10-4 cm, 1.04 eV and 70 Ω (at 5 MHz), respectively. As a result of the experiments, it is observed that the change in electrical parameters becomes more effective at lower frequencies due to the N ss and their relaxation time (τ), dipole and surface polarizations.

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

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Nasrul Arahman

2017-06-01

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

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

Science.gov (United States)

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

2011-01-01

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

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

Energy Technology Data Exchange (ETDEWEB)

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

2017-05-01

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

Modulatory effects of Zn2+ ions on the toxicity of citrate- and PVP-capped gold nanoparticles towards freshwater algae, Scenedesmus obliquus.

Science.gov (United States)

Iswarya, V; Johnson, J B; Parashar, Abhinav; Pulimi, Mrudula; Chandrasekaran, N; Mukherjee, Amitava

2017-02-01

Gold nanoparticles (GNPs) are widely used for medical purposes, both in diagnostics as well as drug delivery, and hence are prone to release and distribution in the environment. Thus, we have explored the effects of GNPs with two distinct surface capping (citrate and PVP), and three different sizes (16, 27, and 37 nm) at 0.01-, 0.1-, and 1-mg L -1 concentrations on a predominant freshwater alga Scenedesmus obliquus in the sterile freshwater matrix. We have also investigated how an abundant metal ion from freshwater, i.e., Zn 2+ ions may modulate the effects of the selected GNPs (40 nm, citrate, and PVP capped). Preliminary toxicity results revealed that gold nanoparticles were highly toxic in comparison to zinc ions alone. A significant modulation in the toxicity of Zn ions was not noticed in the presence of GNPs. In contrast, zinc ions minimized the toxicity produced by GNPs (both CIT-37 and PVP-37), despite its individual toxicity. Approximately, about 42, 33, and 25% toxicity reduction was noted at 0.05-, 0.5-, and 5-mg L -1 Zn ions, respectively, for CIT-37 GNPs, while 31% (0.05 mg L -1 ), 24% (0.5 mg L -1 ), and 9% (5 mg L -1 ) of toxicity reduction were noted for PVP-37 GNPs. Maximum toxicity reduction was seen at 0.05 mg L -1 of Zn ions. Abbott modeling substantiated antagonistic effects offered by Zn 2+ ions on GNPs. Stability and sedimentation data revealed that the addition of zinc ions gradually induced the aggregation of NPs and in turn significantly reduced the toxicity of GNPs. Thus, the naturally existing ions like Zn 2+ have an ability to modulate the toxicity of GNPs in a real-world environment scenario.

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

Science.gov (United States)

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.

Risk Prediction of New Adjacent Vertebral Fractures After PVP for Patients with Vertebral Compression Fractures: Development of a Prediction Model

Energy Technology Data Exchange (ETDEWEB)

Zhong, Bin-Yan; He, Shi-Cheng; Zhu, Hai-Dong [Southeast University, Department of Radiology, Medical School, Zhongda Hospital (China); Wu, Chun-Gen [Shanghai Jiao Tong University Affiliated Sixth People’s Hospital, Department of Diagnostic and Interventional Radiology (China); Fang, Wen; Chen, Li; Guo, Jin-He; Deng, Gang; Zhu, Guang-Yu; Teng, Gao-Jun, E-mail: gjteng@vip.sina.com [Southeast University, Department of Radiology, Medical School, Zhongda Hospital (China)

2017-02-15

PurposeWe aim to determine the predictors of new adjacent vertebral fractures (AVCFs) after percutaneous vertebroplasty (PVP) in patients with osteoporotic vertebral compression fractures (OVCFs) and to construct a risk prediction score to estimate a 2-year new AVCF risk-by-risk factor condition.Materials and MethodsPatients with OVCFs who underwent their first PVP between December 2006 and December 2013 at Hospital A (training cohort) and Hospital B (validation cohort) were included in this study. In training cohort, we assessed the independent risk predictors and developed the probability of new adjacent OVCFs (PNAV) score system using the Cox proportional hazard regression analysis. The accuracy of this system was then validated in both training and validation cohorts by concordance (c) statistic.Results421 patients (training cohort: n = 256; validation cohort: n = 165) were included in this study. In training cohort, new AVCFs after the first PVP treatment occurred in 33 (12.9%) patients. The independent risk factors were intradiscal cement leakage and preexisting old vertebral compression fracture(s). The estimated 2-year absolute risk of new AVCFs ranged from less than 4% in patients with neither independent risk factors to more than 45% in individuals with both factors.ConclusionsThe PNAV score is an objective and easy approach to predict the risk of new AVCFs.

Risk Prediction of New Adjacent Vertebral Fractures After PVP for Patients with Vertebral Compression Fractures: Development of a Prediction Model

International Nuclear Information System (INIS)

Zhong, Bin-Yan; He, Shi-Cheng; Zhu, Hai-Dong; Wu, Chun-Gen; Fang, Wen; Chen, Li; Guo, Jin-He; Deng, Gang; Zhu, Guang-Yu; Teng, Gao-Jun

2017-01-01

PurposeWe aim to determine the predictors of new adjacent vertebral fractures (AVCFs) after percutaneous vertebroplasty (PVP) in patients with osteoporotic vertebral compression fractures (OVCFs) and to construct a risk prediction score to estimate a 2-year new AVCF risk-by-risk factor condition.Materials and MethodsPatients with OVCFs who underwent their first PVP between December 2006 and December 2013 at Hospital A (training cohort) and Hospital B (validation cohort) were included in this study. In training cohort, we assessed the independent risk predictors and developed the probability of new adjacent OVCFs (PNAV) score system using the Cox proportional hazard regression analysis. The accuracy of this system was then validated in both training and validation cohorts by concordance (c) statistic.Results421 patients (training cohort: n = 256; validation cohort: n = 165) were included in this study. In training cohort, new AVCFs after the first PVP treatment occurred in 33 (12.9%) patients. The independent risk factors were intradiscal cement leakage and preexisting old vertebral compression fracture(s). The estimated 2-year absolute risk of new AVCFs ranged from less than 4% in patients with neither independent risk factors to more than 45% in individuals with both factors.ConclusionsThe PNAV score is an objective and easy approach to predict the risk of new AVCFs.

Effect of filler loading of characteristic natural rubber latex (NRL) film filled with nanocrystal cellulose (NCC) and dipersion agent polyvinylpyrrolidone (PVP)

Science.gov (United States)

Harahap, Hamidah; Lubis, Yuni Aldriani; Taslim, Iriany, Nasution, Halimatuddahliana; Agustini, Hamda Eka

2018-04-01

A study has been conducted on the effect of filler loading on NRL films filled with NCC from corn cob waste. This study reviews on the filler loading of NRL film characteristics. The process begins with the production of NCC filler and then proceed with the production NRL film which is processed by coagulant dipping method. NRL is filled with NCC and PVP as dispersion agent of 2, 4, 3, 8 grams (filler loading) and 1% PVP by weight. The production of NRL film started with pre-vulcanization process at 70 °C and followed by vulcanization process at 110 °C for 20 minutes. The results showed that higher filler loading improved the higher crosslink density and mechanical properties of NRL film.

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

Directory of Open Access Journals (Sweden)

Naved Azum

2016-11-01

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

Preparation and evaluation of carvacrol pellets based on PVP solid-dispersion by extrusion-spheronization technique

Directory of Open Access Journals (Sweden)

Z. Taghizadeh*

2017-11-01

Full Text Available Background and objectives: Carvacrol is one of the main pharmacologically active components of Thymus vulgaris essential oil which has shown several therapeutic effects. There are few works regarding the formulation of essential oils as oral solid dosage forms due to their liquid nature, stability and technical problems. The aim of this study was to combine the solid-dispersion approach and extrusion-spheronization technique to produce pellets with desirable physico-mechanical and release properties. Methods: Solid dispersion matrix (30% of carvacrol in polyvinylpyrrolidone K30 was prepared by solvent evaporation. The matrix was mixed with Avicel and lactose and granulated by water. The wet mass was transformed into pellets by extrusion-spheronization. In order to compare the solid dispersion method with the classic approaches, another pellet formulation was prepared by absorption of carvacrol on Aerosil. The pellets were characterized for size (sieve analysis, shape factors (image analysis, mechanical strength, carvacrol content, and release rate (dissolution test. Accelerated stability test of formulations was also carried out. Results: Using suitable composition of solid dispersion matrix and granulation fluid, the pellets with desirable size and shape and mechanical properties could be produced. PVP-based pellets had higher mechanical strength, slower release rate and improved content and stability. The PVP ratio showed considerable effect on release properties of the pellets. Conclusion: Overall, the results revealed the feasibility of preparing desirable pellets containing carvacrol with acceptable content, stability and release properties which can be administered as hard gelatin capsules.

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

Science.gov (United States)

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. Copyright © 2014 Elsevier Inc. All rights reserved.

Ionic Conductivity and Cycling Stability Improvement of PVDF/Nano-Clay Using PVP as Polymer Electrolyte Membranes for LiFePO4 Batteries

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Endah R. Dyartanti

2018-07-01

Full Text Available In this paper, we present the characteristics and performance of polymer electrolyte membranes (PEMs based on poly(vinylidene fluoride (PVDF. The membranes were prepared via a phase-inversion method (non-solvent-induced phase separation (NIPS. As separators for lithium battery systems, additive modified montmorillonite (MMT nano-clay served as a filler and poly(vinylpyrrolidone (PVP was used as a pore-forming agent. The membranes modified with an additive (8 wt % nano-clay and 7 wt % PVP showed an increased porosity (87% and an uptake of a large amount of electrolyte (801.69%, which generated a high level of ionic conductivity (5.61 mS cm−1 at room temperature. A graphite/PEMs/LiFePO4 coin cell CR2032 showed excellent stability in cycling performance (average discharge capacity 127 mA h g−1. Based on these results, PEMs are promising materials to be used in Polymer Electrolyte Membranes in lithium-ion batteries.

Preparation of gold nanoparticles by γ-ray irradiation method using polyvinyl pyrrolidone (PVP) as stabilizer

International Nuclear Information System (INIS)

Nguyen Tan Man; Le Hai; Le Huu Tu; Tran Thu Hong; Tran Thi Tam; Pham Thi Le Ha; Pham Thi Sam

2011-01-01

Gold nanoparticles were prepared from (Au 3+ ) aqueous solution by the method of γ-ray irradiation using polyvinylpyrrolidone (PVP) as stabilizer. The saturated conversion dose (Au 3+ --> Au o ) determined by UV-Vis spectroscopy was found to be about 5 kGy. The UV-Vis spectrum showed that an absorption peak at λ max =524 nm due to surface plasmon resonance. The image of transmission electron microscopy (TEM) showed that the gold nanoparticles are mostly spherical in shape and have an average diameter of ≅20 nm. The prepared colloidal gold nanoparticles solution is good stability for 6 months of storage. (author)

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

Science.gov (United States)

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.

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

International Nuclear Information System (INIS)

Toropainen, V.

2012-05-01

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

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

Energy Technology Data Exchange (ETDEWEB)

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

2012-05-15

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

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

Institute of Scientific and Technical Information of China (English)

方云; 吴梦洁; 任月萍; 江明

2011-01-01

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

Effects of additions of dimethyl siloxanes and ethylene oxide (SEO) copolymers in tensile break (Tb), in gels and swelling percentage of poly(n-vinyl-2-pyrrolidone) (PVP) crosslinking films by electron beams

International Nuclear Information System (INIS)

Souza, A.; Miranda, A.; Hutzler, B.; Silva, L.G.A.; Nunes, S.P.

1997-01-01

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

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

International Nuclear Information System (INIS)

Dinesh, Meghala; Chikkakuntappa, Ranganathaiah

2013-01-01

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 (α ij ) 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

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

Energy Technology Data Exchange (ETDEWEB)

Dinesh, Meghala; Chikkakuntappa, Ranganathaiah, E-mail: crang1@rediffmail.com

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 (α{sub ij}) 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.

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

International Nuclear Information System (INIS)

Park, K.R.; Nho, Y.C.

2003-01-01

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

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

Energy Technology Data Exchange (ETDEWEB)

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

2016-12-01

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

Structural and Electrical Properties of Graphene Oxide-Doped PVA/PVP Blend Nanocomposite Polymer Films

Directory of Open Access Journals (Sweden)

S. K. Shahenoor Basha

2018-01-01

Full Text Available Graphene oxide (GO nanoparticles were incorporated in PVA/PVP blend polymers for the preparation of nanocomposite polymer films by the solution cast technique. XRD, FTIR, DSC, SEM, and UV-visible studies were performed on the prepared nanocomposite polymer films. XRD revealed the amorphous nature of the prepared films. Thermal analysis of the nanocomposite polymer films was analyzed by DSC. SEM revealed the morphological features and the degree of roughness of the samples. DC conductivity studies were under taken on the samples, and the conductivity was found to be 6.13 × 10−4 S·cm−1 for the polymer film prepared at room temperature. A solid-state battery has been fabricated with the chemical composition of Mg+/(PVA/PVP  :  GO/(I2 + C + electrolyte, and its cell parameters like power density and current density were calculated.

Preparation of size-tunable, highly monodisperse PVP-protected Pt-nanoparticles by seed-mediated growth

International Nuclear Information System (INIS)

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

2008-01-01

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 o C and reduced in the presence of a stabilizing polymer poly-N-vinylpyrrolidone (PVP). Slow addition of the Pt-salt will first lead to the formation of nuclei (seeds) which then grow further to produce larger particles of any desired size between 3 and 8 nm. 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 7 nm, 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.

Synthesis, structural and optical properties of PVP coated transition metal doped ZnS nanoparticles

Science.gov (United States)

Desai, N. V.; Shaikh, I. A.; Rawal, K. G.; Shah, D. V.

2018-05-01

The room temperature photoluminescence (PL) of transition metal doped ZnS nanoparticles is investigated in the present study. The PVP coated ZnS nanoparticles doped with transition metals are synthesized by facile wet chemical co-precipitation method with the concentration of impurity 1%. The UV-Vis absorbance spectra have a peak at 324nm which shifts slightly to 321nm upon introduction of the impurity. The incorporation of the transition metal as dopant is confirmed by X-ray diffraction (XRD) and energy dispersive spectroscopy (EDS). The particle size and the morphology are characterized by scanning electron microscopy (SEM), XRD and UV-Vis spectroscopy. The average size of synthesized nanoparticles is about 2.6nm. The room temperature photoluminescence (PL) of undoped and doped ZnS nanoparticles show a strong and sharp peak at 782nm and 781.6nm respectively. The intensity of the PL changes with the type of doping having maximum for manganese (Mn).

Fitness-for-service and decisions for petroleum and chemical equipment. PVP-Volume 315

International Nuclear Information System (INIS)

Prager, M.; Becht, C. IV; Depadova, T.A.; Okazaki, M.; Onyewuenyi, O.A.; Smith, J.P.; Takezono, S.; Weingart, L.J.; Yagi, K.

1995-01-01

This volume is part of a series of publications intended to present the technical foundation for broadly accepted practices to establish the mechanical integrity of equipment in service. A focal point for this activity has been a Materials Properties Council program on fitness-for-service (FSS) reported in earlier PVP volumes. Work reported here covers the full range of equipment of interest to petroleum and chemical companies from LNG to creep service and provides a snapshot of current Codes, methods, concerns, and problems. It encompasses crack-like flaws and local thinning situations, welds, clad vessels, storage tanks, and pressure vessels. The work in progress is only a start, and the papers herein should be viewed as part of the process of validating the techniques used. While most of the applications are to petroleum refineries and natural gas processing plants, some papers deal with fossil-fuel power plants, nuclear power plants, synthetic fuels refineries, and materials for high-temperature applications. Papers have been processed separately for inclusion on the data base

Installation of groundwater observation tubes OL-PVP39 - 40 and drilling of shallow drillhole OL-PP90 at Olkiluoto in Eurajoki 2013

Energy Technology Data Exchange (ETDEWEB)

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

2013-11-15

In order to extend the groundwater monitoring network at Olkiluoto, Posiva Oy contracted Suomen Malmi Oy (Smoy) to install new groundwater observation tubes to two locations and to drill one shallow drillhole with a standpipe. The identification numbers of the groundwater observation tubes are OL-PVP39, OL-PVP40A and 40B, and the shallow drillhole is named OL-PP90. The observation tubes were installed and the shallow hole drilled between July 29th and August 6th in 2013. The drilling rig used in the installation work was a GM-200 rig. Drilling equipment consisted of casing tubes (v 90/77 mm) with drilling bit, 55 mm geo rods and 64 mm drilling bits and T76-equipment for drilling the shallow hole. Monitoring pipes (PVC, v 60/52 mm) were lowered into the holes inside the casings. The monitoring pipes consist of a lower section of riser pipe, a middle section of screen pipe and an upper section of riser pipe. The screen pipe slot size is 0.3 mm and the length of the screen section is two or three metres. Protective stainless steel covers with lock-up caps were installed around the monitoring tubes and the shallow drillholes. In addition to the installation of the tubes, the work included water level measurements after installation. The core samples of the shallow drillhole were logged and reported by geologist. Geological logging included the following parameters: lithology, foliation, fracture parameters, fractured zones, core loss, weathering, fracture frequency, RQD and rock quality. (orig.)

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

Science.gov (United States)

Sarkar, Sumit; Das, Ratan

2017-10-05

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

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

Energy Technology Data Exchange (ETDEWEB)

Baby, Benjamin Hudson; Mohan, D. Bharathi, E-mail: d.bharathimohan@gmail.com [Department of Physics, School of Physical, Chemical and Applied Sciences, Pondicherry University, R.V. Nagar, Kalapet, Puducherry-605014 (India)

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.

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

Directory of Open Access Journals (Sweden)

Xu H

2013-12-01

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

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

Science.gov (United States)

Venugopal, Krishnaveni; Murugappan, Minnoli; Dharmalingam, Sangeetha

2017-07-01

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

Enhanced Radiosensitization Effect of Curcumin Delivered by PVP-PCL Nanoparticle in Lung Cancer

Directory of Open Access Journals (Sweden)

Cuixia Wen

2017-01-01

Full Text Available Curcumin, the principal polyphenolic curcuminoid, has been reported in numerous studies for its antitumor effect in a series of cancers. It is also reported that curcumin possesses radiosensitization effect in some cancers. However, the poor solubility and unsatisfied bioavailability of curcumin significantly undermine its potential application. Here we prepared curcumin loaded nanoparticles by employing PVP-PCL as drug carrier. Characterization studies indicated the satisfied drug loading efficiency and a sustained in vitro release pattern. Quantification uptake study showed that the uptake efficiency of Cum-NPs by lung cancer cells was time- and dose-dependent. In vitro anticancer study demonstrated the superior cytotoxic effect of Cum-NPs with stronger apoptotic induction over free Cum. Most importantly, there is almost no report on the radiosensitization effect of curcumin loaded nanoparticles. Here, Cum-NPs led to more inhibition of the colony forming ability of A549 cells as compared to the equivalent concentration of free Cum as shown in clonogenic assay. Furthermore, Cum-NPs are much more effective in enhancing the tumor growth inhibitory effect of radiation therapy in a A549 xenograft model. Therefore, results from the current study seem to be the first report on the radiosensitization effect of Cum-NPs and paved the way for a curcumin nanodrug delivery system as a potential radiation adjuvant.

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

DEFF Research Database (Denmark)

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

2009-01-01

, both Ag NPs and Ag+ were shown to induce apoptosis and necrosis in THP-1 cells depending on dose and exposure time. Furthermore, the presence of apoptosis could be confirmed by the TUNEL method. A number of studies have implicated the production of reactive oxygen species (ROS) in cytotoxicity mediated...... the effect of well characterized, PVP-coated Ag NPs (69 nm ± 3 nm) and Ag+ in a human monocytic cell line (THP-1). Characterization of the Ag NPs was conducted in both stock suspension and cell media with or without serum and antibiotics. By using the flowcytometric annexin V/propidium iodide (PI) assay...... by NPs. We used the fluorogenic probe, 2′,7′-dichlorofluorescein to assess the levels of intracellular ROS during exposure to Ag NPs and Ag+. A drastic increase in ROS levels could be detected after 6–24 h suggesting that oxidative stress is an important mediator of cytotoxicity caused by Ag NPs and Ag+....

Synthesis and characterization of LiFePo4/C cathode material by freeze drying method with PVP

Directory of Open Access Journals (Sweden)

Kuzmanović Maja D.

2014-01-01

Full Text Available Lithium iron phosphate is a promising cathode material for lithium ion battery application thanks to its good characteristics. Here is presented the freeze drying method for the preparation of carbon coated LiFePO4, where PVP is used as a carbon source. The main advantage of this method is mixing at the atomic level and introducing the carbon source into the precursor solution. The synthesis process can be divided into three stages: freezing of a precursor solution, drying under vacuum until water evaporates and calicination of as-dried powder at slightly reductive atmosphere. Powder X-ray diffraction measurement demonstrated single phase LiFePO4 with crystallite size of 45.8 nm. Morphology and particle size was revealed with scanning electron microscopy and particle size analyzer. Galvanostatic cycling from 2.3 to 4.1 V vs. Li/Li+, shows typical LiFePO4 redox behavior with plateau at 3.4 V. The discharge capacity value obtained at C/10 rate was 154 mAh- 1, with decrease on greater C-rates.

Pathway and mechanism of nitrogen transformation during composting: Functional enzymes and genes under different concentrations of PVP-AgNPs.

Science.gov (United States)

Zeng, Guangming; Zhang, Lihua; Dong, Haoran; Chen, Yaoning; Zhang, Jiachao; Zhu, Yuan; Yuan, Yujie; Xie, Yankai; Fang, Wei

2018-04-01

Polyvinylpyrrolidone coated silver nanoparticles (PVP-AgNPs) were applied at different concentrations to reduce total nitrogen (TN) losses and the mechanisms of nitrogen bio-transformation were investigated in terms of the nitrogen functional enzymes and genes. Results showed that mineral N in pile 3 which was treated with AgNPs at a concentration of 10 mg/kg compost was the highest (6.58 g/kg dry weight (DW) compost) and the TN loss (47.07%) was the lowest at the end of composting. Correlation analysis indicated that TN loss was significantly correlated with amoA abundance. High throughput sequencing showed that the dominant family of ammonia-oxidizing bacteria (AOB) was Nitrosomonadaceae, and the number of Operational Taxonomic Units (OTUs) reduced after the beginning of composting when compared with day 1. In summary, treatment with AgNPs at a concentration of 10 mg/kg compost was considerable to reduce TN losses and reserve more mineral N during composting. Copyright © 2017 Elsevier Ltd. All rights reserved.

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

International Nuclear Information System (INIS)

Darwish, Maher; Mohammadi, Ali; Assi, Navid

2016-01-01

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.

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

Energy Technology Data Exchange (ETDEWEB)

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

2016-02-15

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

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

International Nuclear Information System (INIS)

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

2013-01-01

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 AgNO 3 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.

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

International Nuclear Information System (INIS)

Rakap, Murat

2015-01-01

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

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

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D. Matatagui

2014-01-01

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

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

Energy Technology Data Exchange (ETDEWEB)

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

2015-11-15

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

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

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Mateusz Hecold

2017-01-01

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

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

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Tran Minh Thi

2012-01-01

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

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

KAUST Repository

Mojib, Nazia

2013-03-20

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

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

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Hérica Santos de Oliveira

2011-01-01

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

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

Science.gov (United States)

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

2013-01-01

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

Influence of solvent composition on the miscibility and physical stability of naproxen/PVP K 25 solid dispersions prepared by cosolvent spray-drying.

Science.gov (United States)

Paudel, Amrit; Van den Mooter, Guy

2012-01-01

To investigate the influence of solvent properties on the phase behavior and physical stability of spray-dried solid dispersions containing naproxen and PVP K 25 prepared from binary cosolvent systems containing methanol, acetone and dichloromethane. The viscosity, polymer globular size and evaporation rate of the spray-drying feed solutions were characterized. The solid dispersions were prepared by spray-drying drug-polymer solutions in binary solvent blends containing different proportions of each solvent. The phase behavior was investigated with mDSC, pXRD, FT-IR and TGA. Further, physical stability of solid dispersions was assessed by analyzing after storage at 75% RH. The solid dispersions prepared from solvent/anti-solvent mixture showed better miscibility and physical stability over those prepared from the mixtures of good solvents. Thus, solid dispersions prepared from dichloromethane-acetone exhibited the best physicochemical attributes followed by those prepared from methanol-acetone. FT-IR analysis revealed differential drug-polymer interaction in solid dispersions prepared from various solvent blends, upon the exposure to elevated humidity. Spray-drying from a cocktail of good solvent and anti-solvent with narrower volatility difference produces solid dispersions with better miscibility and physical stability resulting from the simultaneous effect on the polymer conformation and better dispersivity of drug.

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

International Nuclear Information System (INIS)

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

2012-01-01

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

Evaluation of a Solid Dispersion of Curcumin With Polyvinylpyrrolidone and Boric Acid Against Salmonella Enteritidis Infection and Intestinal Permeability in Broiler Chickens: A Pilot Study

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Daniel Hernandez-Patlan

2018-06-01

Full Text Available In the present study, in vitro assays were conducted to evaluate the solubility of curcumin (CUR alone or with polyvinylpyrrolidone (PVP at different pH, as well as its permeability in Caco-2 cells. Results confirmed that the solid dispersion of CUR with PVP (CUR/PVP at a 1:9 ratio, significantly increased (P < 0.05 solubility and permeability compared to CUR alone. Then, the antimicrobial activity of CUR/PVP, boric acid (BA, and a combination of 0.5% CUR/PVP and 0.5% BA (CUR/PVP-BA against Salmonella Enteritidis (SE was determined using an in vitro digestion model that simulates crop, proventriculus, and intestine. The results revealed that in the proventriculus and intestinal compartments significant reductions of SE were observed in all the experimental treatments, but 1% BA eliminated SE in the intestinal compartment and CUR/PVP-BA showed a synergistic effect on antimicrobial activity against SE. To complement these findings, two independent in vivo trials were conducted to determine the effect of 0.1% CUR/PVP; 0.1% BA; or the combination of 0.05% CUR/PVP (1:9 ratio and 0.05% BA (CUR/PVP-BA on the antimicrobial activity against SE, intestinal permeability and inflammatory responses in broiler chickens. BA at 0.1% had no significant in vivo effects against SE. However, the combination of 0.05% BA and 0.05% CUR/PVP and 0.05% BA was sufficient to reduce crop and intestinal SE colonization in broiler chickens in two independent trials, confirming the synergic effect between them. A similar antimicrobial impact against SE intestinal colonization was observed in chickens treated with 0.1% CUR/PVP at a 1:9 ratio, which could be due to the increase in solubility of CUR by PVP. Furthermore, 0.1% CUR/PVP reduced the intestinal permeability of FITC-d and total intestinal IgA, as well as increase the activity of SOD when compared to control, while, CUR/PVP-BA only decreased SOD activity. Further studies to confirm and expand the in vivo results obtained

Improved dehydriding property of polyvinylpyrrolidone coated Mg-Ni hydrogen storage nano-composite prepared by hydriding combustion synthesis and wet mechanical milling

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Linglong Yao

2018-02-01

Full Text Available In this work, polyvinylpyrrolidone (PVP coated Mg95Ni5 nano-composites were prepared by hydriding combustion synthesis (HCS plus wet mechanical milling (WM with tetrahydrofuran (THF and donated as WM-x wt% PVP (x = 1, 3, 5 and 7 respectively. The phase compositions, microstructures and dehydriding property, as well as the co-effect of PVP and THF were investigated in detail. XRD results showed that the average crystal size of MgH2 in the milled Mg95Ni5 decreased from 23 nm without PVP to 18 nm with 1 wt% PVP. The peak temperature of dehydrogenation of MgH2 in the milled Mg95Ni5 decreased from 293.0 °C without THF to 250.4 °C with THF. The apparent activation energy for decomposition of MgH2 in WM-7 wt% PVP was estimated to be 66.94 kJ/mol, which is 37.70 kJ/mol lower than that of milled Mg95Ni5 without THF and PVP. PVP and THF can facilitate the refinement of particle size during mechanical milling process. Attributed to small particle sizes and synergistic effect of PVP and THF, the composites exhibit markedly improved dehydriding properties. Keywords: Mg-Ni-PVP, Composite, Mg-based alloy, Wet mechanical milling, Dehydriding temperature

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

Energy Technology Data Exchange (ETDEWEB)

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

2014-11-30

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

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

International Nuclear Information System (INIS)

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

2014-01-01

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

Volumetric and isentropic compressibility behaviour of aqueous solutions of (polyvinylpyrrolidone + sodium citrate) at T = (283.15 to 308.15) K

International Nuclear Information System (INIS)

Sadeghi, Rahmat; Ziamajidi, Fatemeh

2007-01-01

The apparent specific volumes and isentropic compressibilities have been determined for polyvinylpyrrolidone in aqueous solutions of sodium citrate by density and sound velocity measurements at T = (283.15 to 308.15) K at atmospheric pressure. The results show a positive transfer volume of PVP from an aqueous solution to an aqueous sodium citrate solution. For low concentrations of PVP, the apparent specific volumes of PVP in water increased along with an increase in the polymer mass fraction, while in aqueous sodium citrate solutions decreased along with an increase in the polymer mass fraction. For high concentrations of PVP, the apparent specific volumes of PVP in water and in aqueous sodium citrate solutions were independent of the polymer mass fraction. The apparent specific isentropic compressibility of PVP is negative at T = (283.15 and 288.15) K, which imply that the water molecules around the PVP molecules are less compressible than the water molecules in the bulk solutions. The positive values of apparent specific isentropic compressibility at T = (298.15, 303.15, and 308.15) K imply that the water molecules around the PVP molecules are more compressible than the water molecules in the bulk solutions. Finally, it was found that the apparent specific isentropic compressibility of PVP increases as the concentration of sodium citrate increases

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

Energy Technology Data Exchange (ETDEWEB)

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

2014-10-15

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

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

Energy Technology Data Exchange (ETDEWEB)

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

2014-05-01

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

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

Energy Technology Data Exchange (ETDEWEB)

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

2015-04-24

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

How Structure-Directing Agents Control Nanocrystal Shape: Polyvinylpyrrolidone-Mediated Growth of Ag Nanocubes.

Science.gov (United States)

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

2015-11-11

The importance of structure-directing agents (SDAs) in the shape-selective synthesis of colloidal nanostructures has been well documented. However, the mechanisms by which SDAs actuate shape control are poorly understood. In the polyvinylpyrrolidone (PVP)-mediated growth of {100}-faceted Ag nanocrystals, this capability has been attributed to preferential binding of PVP to Ag(100). We use molecular dynamics simulations to probe the mechanisms by which Ag atoms add to Ag(100) and Ag(111) in ethylene glycol solution with PVP. We find that PVP induces kinetic Ag nanocrystal shapes by regulating the relative Ag fluxes to these facets. Stronger PVP binding to Ag(100) leads to a larger Ag flux to Ag(111) and cubic nanostructures through two mechanisms: enhanced Ag trapping by more extended PVP films on Ag(111) and a reduced free-energy barrier for Ag to cross lower-density films on Ag(111). These flux-regulating capabilities depend on PVP concentration and chain length, consistent with experiment.

Synthesis of PbS/poly (vinyl-pyrrolidone) nanocomposite

International Nuclear Information System (INIS)

Patel, Jayesh D.; Chaudhuri, Tapas K.

2009-01-01

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

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

Science.gov (United States)

Ukah, Ndubuisi Benjamin

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

Effect of body temperature on peripheral venous pressure measurements and its agreement with central venous pressure in neurosurgical patients.

Science.gov (United States)

Sahin, Altan; Salman, M Alper; Salman, A Ebru; Aypar, Ulka

2005-04-01

Previous studies suggest a correlation of central venous pressure (CVP) with peripheral venous pressure (PVP) in different clinical settings. The effect of body temperature on PVP and its agreement with CVP in patients under general anesthesia are investigated in this study. Fifteen American Society of Anesthesiologists I-II patients undergoing elective craniotomy were included in the study. CVP, PVP, and core (Tc) and peripheral (Tp) temperatures were monitored throughout the study. A total of 950 simultaneous measurements of CVP, PVP, Tc, and Tp from 15 subjects were recorded at 5-minute intervals. The measurements were divided into low- and high-Tc and -Tp groups by medians as cutoff points. Bland-Altman assessment for agreement was used for CVP and PVP in all groups. PVP measurements were within range of +/-2 mm Hg of CVP values in 94% of the measurements. Considering all measurements, mean bias was 0.064 mm Hg (95% confidence interval -0.018-0.146). Corrected bias for repeated measurements was 0.173 +/- 3.567 mm Hg (mean +/- SD(corrected)). All of the measurements were within mean +/- 2 SD of bias, which means that PVP and CVP are interchangeable in our setting. As all the measurements were within 1 SD of bias when Tc was > or = 35.8 degrees C, even a better agreement of PVP and CVP was evident. The effect of peripheral hypothermia was not as prominent as core hypothermia. PVP measurement may be a noninvasive alternative for estimating CVP. Body temperature affects the agreement of CVP and PVP, which deteriorates at lower temperatures.

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

KAUST Repository

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

2013-01-01

In this paper, we describe the UV and cold tolerance of a purple violet pigment (PVP)-producing Antarctic bacterium, Janthinobacterium sp. Ant5-2 (PVP+) and compared its physiological adaptations with a pigmentless mutant strain (PVP-). A

A waitlist control-group study of cognitive, mood, and quality of life outcome after posteroventral pallidotomy in Parkinson disease.

Science.gov (United States)

Carr, Jason A R; Honey, Christopher R; Sinden, Marci; Phillips, Anthony G; Martzke, Jeffrey S

2003-07-01

The aim of this study was to examine neuropsychological outcome from unilateral posteroventral pallidotomy (PVP) in Parkinson disease while controlling for confounding factors such as test practice and disease progression. Participants underwent baseline and 2-month follow-up assessments of cognition, quality of life, mood, and motor functioning. The surgery group (22 patients) underwent PVP (15 left, seven right) after baseline assessment. The waitlist group (14 patients) underwent PVP after follow up. At follow up, the left PVP group exhibited a decline on verbal measures of learning, fluency, working memory, and speeded color naming. The incidence of significant decline on these measures after left PVP ranged from 50 to 86%. The right PVP group did not exhibit a significant cognitive decline, but fluency did decline in 71% of patients who underwent right PVP. Participants who underwent PVP reported better bodily pain and social functioning at follow up than participants in the waitlist group. Improved bodily pain was evident for 62% of the surgery group, and social functioning improved for 19%. Surgery did not alter reported physical functioning or mood. Dyskinesia improved after surgery, but there were no improvements in "on-state" manual dexterity or handwriting. Most patients who underwent left PVP exhibited declines in learning, fluency, working memory, and speeded color naming. Accounting for retesting effects altered the magnitude of these declines by up to one quarter of a standard deviation, but did not increase the breadth of postsurgical neuropsychological decline beyond that typically reported in the literature. It was found that PVP improved dyskinesia, bodily pain, and social functioning, but did not lead to improvement on other objective and self-reported measures of motor functioning.

Effects of Facet Joint Injection Reducing the Need for Percutaneous Vertebroplasty in Vertebral Compression Fractures

Energy Technology Data Exchange (ETDEWEB)

Im, Tae Seong; Lee, Joon Woo; Lee, Eugene; Kang, Yusuhn; Ahn, Joong Mo, E-mail: joongmoahn@gmail.com; Kang, Heung Sik [Seoul National University Bundang Hospital, Department of Radiology (Korea, Republic of)

2016-05-15

ObjectiveTo evaluate the effects of facet joint injection (FJI) reducing the need for percutaneous vertebroplasty (PVP) in cases of vertebral compression fracture (VCF).Materials and MethodsA total of 169 patients who were referred to the radiology department of our institution for PVP between January 2011 and December 2014 were retrospectively evaluated. The effectiveness of FJI was evaluated by the proportion of patients who cancelled PVP and who experienced reduced pain. In addition, by means of medical chart and MRI review, those clinical factors (age, sex, history of trauma, amount of injected steroids and interval days elapsed between VCF and FJI) and MR image factors (kyphosis angle, height loss, single or multiple level of VCF, burst fracture, central canal compromise, posterior element injury) that were believed to be significant for the effectiveness of FJI were statistically analysed.ResultsIn the 26 patients with FJI prior to PVP, six (23 %) patients cancelled PVP with considerable improvement in reported pain. In the 20 patients with PVP after FJI, improvement in pain after FJI was reported by six patients, resulting in a total of 12 patients (46 %) who experienced reduced pain after FJI. Clinical factors and MR image factors did not show any statistically significant difference between those groups, divided by PVP cancellation and by improvement of pain.ConclusionAfter FJI prior to PVP, about one quarter of patients cancelled PVP due to reduced pain and overall about half of the patients experienced reduced pain.

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

Science.gov (United States)

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. Copyright © 2011 Elsevier B.V. All rights reserved.

Optical properties of silica-coated Y2O3:Er,Yb nanoparticles in the presence of polyvinylpyrrolidone

International Nuclear Information System (INIS)

Fujii, Kunio; Kitamoto, Yoshitaka; Hara, Masahiko; Odawara, Osamu; Wada, Hiroyuki

2014-01-01

The optical properties of polyvinylpyrrolidone (PVP)-adsorbed and silica-coated Y 2 O 3 :Er,Yb nanoparticles produced by using PVP were studied for potential bio-applications of upconversion nanoparticles. We utilized PVP to better disperse Y 2 O 3 :Er,Yb nanoparticles in solution and to prepare silica-coated Y 2 O 3 :Er,Yb nanoparticles. The fluorescent intensity of PVP-adsorbed Y 2 O 3 :Er,Yb nanoparticles was 1.25 times higher than non-adsorbed Y 2 O 3 :Er,Yb nanoparticles, which was probably due to surface defects in Y 2 O 3 :Er,Yb nanoparticles being covered by the PVP. However, the fluorescent intensity of silica-coated Y 2 O 3 :Er,Yb nanoparticles decreased as silica layer thickness increased. This could be ascribed to the higher vibrational energy of PVP than that of the silica structure. Therefore, the optimum silica layer thickness is important in bio-applications to avoid deterioration of the optical properties of Y 2 O 3 :Er,Yb nanoparticles. - Highlights: • We prepared the silica-coated upconversion nanoparticles by using PVP. • We showed that PVP played an important role in coating nanoparticles. • PL intensity of silica-coated nanoparticles decreased as silica layer thickness increased

Expression of Aleutian mink disease parvovirus capsid proteins in defined segments: localization of immunoreactive sites and neutralizing epitopes to specific regions.

Science.gov (United States)

Bloom, M E; Martin, D A; Oie, K L; Huhtanen, M E; Costello, F; Wolfinbarger, J B; Hayes, S F; Agbandje-McKenna, M

1997-01-01

The capsid proteins of the ADV-G isolate of Aleutian mink disease parvovirus (ADV) were expressed in 10 nonoverlapping segments as fusions with maltose-binding protein in pMAL-C2 (pVP1, pVP2a through pVP2i). The constructs were designed to capture the VP1 unique sequence and the portions analogous to the four variable surface loops of canine parvovirus (CPV) in individual fragments (pVP2b, pVP2d, pVP2e, and pVP2g, respectively). The panel of fusion proteins was immunoblotted with sera from mink infected with ADV. Seropositive mink infected with either ADV-TR, ADV-Utah, or ADV-Pullman reacted preferentially against certain segments, regardless of mink genotype or virus inoculum. The most consistently immunoreactive regions were pVP2g, pVP2e, and pVP2f, the segments that encompassed the analogs of CPV surface loops 3 and 4. The VP1 unique region was also consistently immunoreactive. These findings indicated that infected mink recognize linear epitopes that localized to certain regions of the capsid protein sequence. The segment containing the hypervariable region (pVP2d), corresponding to CPV loop 2, was also expressed from ADV-Utah. An anti-ADV-G monoclonal antibody and a rabbit anti-ADV-G capsid antibody reacted exclusively with the ADV-G pVP2d segment but not with the corresponding segment from ADV-Utah. Mink infected with ADV-TR or ADV-Utah also preferentially reacted with the pVP2d sequence characteristic of that virus. These results suggested that the loop 2 region may contain a type-specific linear epitope and that the epitope may also be specifically recognized by infected mink. Heterologous antisera were prepared against the VP1 unique region and the four segments capturing the variable surface loops of CPV. The antisera against the proteins containing loop 3 or loop 4, as well as the anticapsid antibody, neutralized ADV-G infectivity in vitro and bound to capsids in immune electron microscopy. These results suggested that regions of the ADV capsid proteins

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

Energy Technology Data Exchange (ETDEWEB)

Yao, Qingqing [Institute of Advanced Materials for Nano-Bio Applications, School of Ophthalmology & Optometry, Wenzhou Medical University, 270 Xueyuan Xi Road, Wenzhou, Zhejiang 325027 (China); Li, Wei [Institute of Biomaterials, Department of Materials Science and Engineering, University of Erlangen-Nuremberg, Cauerstrasse 6, Erlangen 91058 (Germany); Yu, Shanshan; Ma, Liwei [Institute of Advanced Materials for Nano-Bio Applications, School of Ophthalmology & Optometry, Wenzhou Medical University, 270 Xueyuan Xi Road, Wenzhou, Zhejiang 325027 (China); Jin, Dayong [Institute for Biomedical Materials and Devices, Faculty of Science, University of Technology Sydney, NSW 2007 (Australia); Advanced Cytometry Labs, ARC Center of Excellence for Nanoscale BioPhotonics, Macquarie University, Sydney, NSW 2109 (Australia); Boccaccini, Aldo R., E-mail: Aldo.Boccaccini@ww.uni-erlangen.de [Institute of Biomaterials, Department of Materials Science and Engineering, University of Erlangen-Nuremberg, Cauerstrasse 6, Erlangen 91058 (Germany); Liu, Yong, E-mail: yongliu1980@hotmail.com [Institute of Advanced Materials for Nano-Bio Applications, School of Ophthalmology & Optometry, Wenzhou Medical University, 270 Xueyuan Xi Road, Wenzhou, Zhejiang 325027 (China); Advanced Cytometry Labs, ARC Center of Excellence for Nanoscale BioPhotonics, Macquarie University, Sydney, NSW 2109 (Australia)

2015-11-01

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

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

International Nuclear Information System (INIS)

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

2015-01-01

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

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

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Guang-Quan Zhang

2015-01-01

Full Text Available Background: Post traumatic osteonecrosis of a vertebral body occurring in a delayed fashion was first described by the German doctor Kümmell in 1895. Several studies have reported percutaneous vertebroplasty (PVP, or percutaneous kyphoplasty (PKP for Kümmell's disease achieves good outcomes. However, it is unknown whether a technique is superior for the treatment of this disease. The objective of the study is to compare the efficacy of PVP and PKP for the treatment of Kümmell's disease. Materials and Methods: A retrospective review was conducted for 73 patients with Kümmell's disease. PVP was performed in 38 patients and PKP in 35 patients. Visual analogue score (VAS was used to evaluate pain. The anterior vertebral height was measured. The operative time, the incidence of cement leakage and the costs were recorded. Results: In both PVP group and PKP group, the VAS and anterior vertebral height significantly improved at 1-day postoperatively (P 0.05. Between the PVP and PKP groups, there were no significant differences in VAS and the anterior vertebral height at 1-day postoperatively and at the final followup (P > 0.05. The operating time and expense in the PKP group were higher than the PVP group (P < 0.001. Cement leakages in the PKP group were fewer than PVP group (P < 0.05. Conclusions: PVP is a faster, less expensive option that still provides a comparable pain relief and restoration of vertebral height to PKP for the treatment of Kümmell's disease. PKP has a significant advantage over PVP in term of the fewer cement leakages.

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

Directory of Open Access Journals (Sweden)

Tatyana Gutul

2014-04-01

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

Preparation of Polyvinyl Pyrrolidone-Based Hydrogels by Radiation Induced Crosslinking with Potential Application as Wound Dressing

International Nuclear Information System (INIS)

Abd EI-Mohdy, H.L.; Hegazy, E.A.

2009-01-01

Polyvinyl pyrrolidone l polyethylene glycol hydrogels (PVP/ PEG) and PVP/ PEG/ Starch were prepared by irradiating the mixtures of aqueous solutions of PVP, PEG and starch with electron beam at different doses. Its properties were evaluated to identify their usability in wound dressing applications. Hydrogel dressing can protect injured skin and keep it appropriately moist to speed the healing process. The physical properties of the prepared hydrogels, such as gel content, swelling, water content and degree of water evaporation with varying composition and irradiation dose were examined to evaluate the usefulness of the hydrogels for wound dressing. The gel content increases with increasing PVP concentration due to increased crosslink density, and decreases with increasing the PEG concentration. PEG seems to act not only as plasticizer but also to modify the gel properties as gelation% and maximum swelling. Mechanical experiments were conducted for both of PVP/PEG and PVP/PEG/ Starch. The adding of PEG and starch to PVP significantly improve elongation and tensile strength of prepared hydrogels. The crystallinity of prepared hydrogels was investigated with varying their components. XRD studies indicated that the crystallinity in the gel was mainly due to PVP and decreased with enhanced starch content. The prepared hydrogels had sufficient strength to be used as wound dressing and could be considered as a good barrier against microbes

Photoalignment of a Bisazodioxodibenzothiophene in a Polyvinylpyrrolidone Matrix

Science.gov (United States)

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.

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

Science.gov (United States)

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

2016-10-01

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). 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. 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 portal hypertension was 0.95. 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.

Percutaneous Vertebroplasty Relieves Pain in Cervical Spine Metastases

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Li Bao

2017-01-01

Full Text Available 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.

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

Science.gov (United States)

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

2016-10-01

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

Performance evaluation and mass transfer study of CO2 absorption in flat sheet membrane contactor using novel porous polysulfone membrane

International Nuclear Information System (INIS)

Nabian, Nima; Ghoreyshi, Ali Asghar; Rahimpour, Ahmad; Shakeri, Mohsen

2015-01-01

The performance of gas-liquid membrane contactor for CO 2 capture was investigated using a novel polysulfone (PSF) flat membrane prepared via non-solvent phase inversion method. Polyvinyl pyrrolidone (PVP) was used as an additive in the dope solution of PSF membranes. Morphological studies by scanning electron microscopy (SEM) analysis revealed that PSF membrane with PVP has a finger-like structure, but the PSF membrane without PVP has a sponge-like structure. Also, characterization results through atomic force microscopy (AFM) and contact angle measurement demonstrated that the porosity, surface roughness and hydrophobicity of the PSF membrane increased with addition of PVP to the dope solution. Mass transfer resistance analysis, based on CO 2 absorption flux, displayed that addition of PVP to the dope solution of PSF membrane decreased membrane mass transfer resistance, and significantly improved CO 2 absorption flux up to 2.7 and 1.8 times of absorption fluxes of PSF membrane without PVP and commercial PVDF, respectively.

Vertebroplasty in the treatment of back pain; Vertebroplastie zur Therapie des Rueckenschmerzes

Energy Technology Data Exchange (ETDEWEB)

Trumm, C.G.; Jakobs, T.F.; Zech, C.J.; Weber, C.; Reiser, M.F.; Hoffmann, R.T. [Klinikum Grosshadern der Ludwig-Maximilians-Universitaet, Institut fuer Klinische Radiologie, Muenchen (Germany)

2006-06-15

Percutaneous vertebroplasty (PVP) represents a minimally invasive option which is gaining in importance for the treatment of vertebral compression fractures (VCF) and osteolysis of the spine. This article describes the indications for its use, peri-interventional imaging, technique, and results of PVP. The current guidelines for performance of PVP are explained in accordance with the ''Interdisciplinary Consensus Paper on Vertebroplasty and Kyphoplasty'' of the German Professional Associations and the 2005 CIRSE Guidelines. The results of our own study carried out in 2002 are compared to the complication rates and clinical outcomes reported in the literature. Painful osteoporotic VCF and osteolysis within the vertebral body due to metastases and multiple myeloma are indications for PVP. Absolute contraindications are, in particular, asymptomatic VCF, alleviation of pain by drug treatment, therapy-refractory coagulopathies, allergies to cement components, and active infections. MRI or CT is indicated before undertaking PVP to assess the fracture age, to exclude other causes of pain, and to evaluate the posterior edge of the vertebral body. High-quality mono- or biplanar fluoroscopy - preferably in combination with CT (fluoroscopy) - is necessary for PVP to minimize the risk of cement leakage. A clear reduction in pain [mean reduction of 6.1 points (VAS)] is achieved in 86-92% of the patients with PVP. Our own study treating 58 patients (mean follow-up 323{+-}99 days) revealed a clear alleviation of pain in 77% [-5.7 points (VAS)]. PVP constitutes a safe and effective minimally invasive treatment approach to stabilize and reduce acute and chronic back pain due to osteoporotic VCF and tumor-associated osteolysis. (orig.) [German] Die perkutane Vertebroplastie (PVP) stellt bei osteoporotischen Wirbelkoerperfrakturen (WKF) und Osteolysen der Wirbelsaeule eine minimalinvasive Behandlungsmoeglichkeit dar, die zunehmend an Bedeutung gewinnt. In diesem

Low frequency dielectric relaxation processes and ionic conductivity of montmorillonite clay nanoparticles colloidal suspension in poly(vinyl pyrrolidone−ethylene glycol blends

Directory of Open Access Journals (Sweden)

2008-11-01

Full Text Available The dielectric dispersion behaviour of montmorillonite (MMT clay nanoparticles colloidal suspension in poly(vinyl pyrrolidone-ethylene glycol (PVP-EG blends were investigated over the frequency range 20 Hz to 1 MHz at 30°C. The 0, 1, 2, 3, 5 and 10 wt% MMT clay concentration of the weight of total solute (MMT+PVP were prepared in PVP-EG blends using EG as solvent. The complex relative dielectric function, alternating current (ac electrical conductivity, electric modulus and impedance spectra of these materials show the relaxation processes corresponding to the micro-Brownian motion of PVP chain, ion conduction and electrode polarization phenomena. The real part of ac conductivity spectra of these materials obeys Jonscher power law σ′(ω =σdc + Aωn in upper frequency end of the measurement, whereas dispersion in lower frequency end confirms the presence of electrode polarization effect. It was observed that the increase of clay concentration in the PVP-EG blends significantly increases the ac conductivity values, and simultaneously reduces the ionic conductivity relaxation time and electric double layer relaxation time, which suggests that PVP segmental dynamics and ionic motion are strongly coupled. The intercalation of EG structures in clay galleries and exfoliation of clay sheets by adsorption of PVP-EG structures on clay surfaces are discussed by considering the hydrogen bonding interactions between the hydroxyl group (–OH of EG molecules, carbonyl group (C=O of PVP monomer units, and the hydroxylated aluminate surfaces of the MMT clay particles. Results suggest that the colloidal suspension of MMT clay nano particles in the PVP-EG blends provide a convenient way to obtain an electrolyte solution with tailored electrical conduction properties.

High luminescent fibers with hybrid SiO2-coated CdTe nanocrystals fabricated by electrospinning technique

International Nuclear Information System (INIS)

Cao, Yongqiang; Liu, Ning; Yang, Ping; Shi, Ruixia; Ma, Qian; Zhang, Aiyu; Zhu, Yuanna; Wang, Junpeng; Wang, Jianrong

2015-01-01

The polyvinylpyrrolidone (PVP) hybrid luminescent micro-/nanofibers doped with the novel hybrid SiO 2 -coated CdTe nanocrystals (HS-CdTe NCs) have been fabricated for the first time via the electrospinning technique. The morphologies and photoluminescence (PL) emissions of HS-CdTe/PVP micro-/nanofibers prepared by doping the HS-CdTe NCs with the different PL peak wavelength (571, 616, and 643 nm) in PVP fibers were investigated by optical and PL microscope. The results revealed that all the HS-CdTe/PVP hybrid fibers showed an ultralong length for several hundreds of micrometers and a relatively uniform diameter of 1000 ∼ 1200 nm. The hybrid fibers displayed a wavelength-tunable PL emission, determining by the PL of doped HS-CdTe NCs. Moreover, similar to the original PL properties of HS-CdTe NCs before the electrospinning, the HS-CdTe/PVP fibers also showed a series of superior PL properties, such as narrow and symmetry PL spectrum, high, and uniform brightness. For comparison purpose, we also prepared three CdTe/PVP hybrid fibers by doping the 553 nm, 600 nm, and 633 nm PL-emitting CdTe NCs respectively in PVP electrospinning fibers. The characterization results showed that, the obtained three CdTe/PVP hybrid fibers had a basically satisfactory micro-/nanofiber morphology with a long length and relatively uniform diameter, but all the fibers exhibited very weak PL emissions. The enormous contrast in PL properties between HS-CdTe/PVP and CdTe/PVP fibers should mainly be ascribed to the different connection modes of ligands with the NCs and the passivation effect of inert hybrid silica shell on HS-CdTe. It is hopeful that the high luminescent HS-CdTe/PVP micro-/nanofibers with the tunable PL peak wavelength would be a good candidate in the optical sensor, light-emitting devices (LEDs), nanometer-scale waveguides, and the other related photonic materials. - Highlights: • The HS-CdTe/PVP electrospun hybrid fibers were fabricated for the first time. • The

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

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AKHTAR SAEED

2006-01-01

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

Manipulating interfacial polymer structures through mixed surfactant adsorption and complexation.

Science.gov (United States)

Cattoz, Beatrice; de Vos, Wiebe M; Cosgrove, Terence; Crossman, Martin; Prescott, Stuart W

2012-04-17

The effects of a nonionic alcohol ethoxylate surfactant, C(13)E(7), on the interactions between PVP and SDS both in the bulk and at the silica nanoparticle interface are studied by photon correlation spectroscopy, solvent relaxation NMR, SANS, and optical reflectometry. Our results confirmed that, in the absence of SDS, C(13)E(7) and PVP are noninteracting, while SDS interacts strongly both with PVP and C(13)E(7) . Studying interfacial interactions showed that the interfacial interactions of PVP with silica can be manipulated by varying the amounts of SDS and C(13)E(7) present. Upon SDS addition, the adsorbed layer thickness of PVP on silica increases due to Coulombic repulsion between micelles in the polymer layer. When C(13)E(7) is progressively added to the system, it forms mixed micelles with the complexed SDS, reducing the total charge per micelle and thus reducing the repulsion between micelle and the silica surface that would otherwise cause the PVP to desorb. This causes the amount of adsorbed polymer to increase with C(13)E(7) addition for the systems containing SDS, demonstrating that addition of C(13)E(7) hinders the SDS-mediated desorption of an adsorbed PVP layer. © 2012 American Chemical Society

Sonochemical synthesis of PVA/PVP blend nanocomposite containing modified CuO nanoparticles with vitamin B1 and their antibacterial activity against Staphylococcus aureus and Escherichia coli.

Science.gov (United States)

Mallakpour, Shadpour; Mansourzadeh, Soheila

2018-05-01

The aim of this paper was to blend the polymers, poly(N-vinyl-2-pyrrolidone) (PVP) and poly(vinyl alcohol) (PVA) to produce a novel composite materials possessing the benefits of both. CuO nanoparticles (NPs) were used as a suitable filler to fabricate the blend nanocomposites (NCs) with desired properties. First, the surface of NPs, was modified with vitamin B 1 (VB 1 ) as a bio-safe coupling agent. Then, the blend NCs with various ratios of modified CuO (3, 5, and 7 wt%) were fabricated under ultrasonic irradiations followed by casting/solvent evaporation method. These processes are fast and green way to disperse the NPs sufficiently. Several techniques were applied for the characterization of the obtained NCs. morphology examination demonstrated the morphology of NCs and compatibility of NPs with the blend polymer. EDX results indicated the weight and atomic percentage of the achieved materials. TGA analysis verified that the NCs show higher thermal properties than the neat blend polymer. Also embedding the modified NPs into the blend polymer had effected on optical absorbance of the obtained NCs. The contact angle measurements confirmed that the hydrophilicity decreased for different proportions of the modified NPs loaded in the blend polymer. Finally, NCs show better bactericidal effects against gram-positive than gram-negative bacteria. Copyright © 2018 Elsevier B.V. All rights reserved.

Is portal venous pressure modulation still indicated for all recipients in living-donor liver transplantation?

Science.gov (United States)

Yao, Siyuan; Kaido, Toshimi; Uozumi, Ryuji; Yagi, Shintaro; Miyachi, Yosuke; Fukumitsu, Ken; Anazawa, Takayuki; Kamo, Naoko; Taura, Kojiro; Okajima, Hideaki; Uemoto, Shinji

2018-04-30

There is a consensus that portal venous pressure (PVP) modulation prevents portal hypertension (PHT) and consequent complications after adult living donor liver transplantation (ALDLT). However, PVP-modulation strategies need updating based on most recent findings. We examined our 10-year experience of PVP modulation and reevaluate whether it is necessary for all recipients or selected recipients in ALDLT. In this retrospective study, 319 patients who underwent ALDLT from 2007 to 2016 were divided into three groups according to the necessity and results of PVP modulation: not indicated (n=189), indicated and successful (n=92), and indicated but failed (n=38). Graft survival and associations with various clinical factors were investigated. PVP modulation was performed mainly by splenectomy to lower final PVP to ≤15 mmHg. Successful PVP modulation improved prognosis that was equivalent to that of patients who did not need modulation, whereas failed modulation was associated with increased incidence of small-for-size syndrome (SFSS) (p=0.003), and early graft loss (EGL) (p=0.006). Among patients with failed modulation, donor age ≥45 years (hazard ratio [HR], 3.67; p=0.02) and ABO incompatibility (HR, 3.90; p=0.01) were independent risk factors for graft loss. Survival analysis showed that PVP >15 mmHg was related to poor prognosis in grafts from either ABO-incompatible or older donor aged ≥45 years (pmodulation is not necessarily required in all recipients. While grafts from both ABO-compatible/identical and young donor can tolerate PHT, lowering PVP to ≤15 mmHg is a key to preventing SFSS and consequent EGL with grafts from either ABO-incompatible or older donors. This article is protected by copyright. All rights reserved. © 2018 by the American Association for the Study of Liver Diseases.

Effects of Interfacial Charge Depletion in Organic Thin-Film Transistors with Polymeric Dielectrics on Electrical Stability

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Jaehoon Park

2010-06-01

Full Text Available We investigated the electrical stabilities of two types of pentacene-based organic thin-film transistors (OTFTs with two different polymeric dielectrics: polystyrene (PS and poly(4-vinyl phenol (PVP, in terms of the interfacial charge depletion. Under a short-term bias stress condition, the OTFT with the PVP layer showed a substantial increase in the drain current and a positive shift of the threshold voltage, while the PS layer case exhibited no change. Furthermore, a significant increase in the off-state current was observed in the OTFT with the PVP layer which has a hydroxyl group. In the presence of the interfacial hydroxyl group in PVP, the holes are not fully depleted during repetitive operation of the OTFT with the PVP layer and a large positive gate voltage in the off-state regime is needed to effectively refresh the electrical characteristics. It is suggested that the depletion-limited holes at the interface, i.e., interfacial charge depletion, between the PVP layer and the pentacene layer play a critical role on the electrical stability during operation of the OTFT.

Radiation Synthesis of Super absorbent CMC Based Hydrogels For Agriculture Applications

International Nuclear Information System (INIS)

Raafat, A.I.; Eid, M.; El-Arnaouty, M.B.

2010-01-01

A good hydrogels of carboxy methyl cellulose (CMC) and poly vinyl pyrrolidone (PVP) were synthesized by gamma radiation at different doses and compositions. The prepared hydrogels were characterized by (FTIR) and (SEM). The hydrogels properties such as gelation (%), swelling and water retention capability were investigated. As the content of PVP in PVP/CMC hydrogels increased the gelation (%) increased. The swelling ratio of prepared hydrogel decreased with increasing of irradiation doses and the temperature. The (PVP/CMC) hydrogen of composition (40:60) prepared at 20 kGy showed the highest swelling ratio. The addition of sodium bicarbonate (NaHCO 3 ) to the PVP/CMC hydrogels during the irradiation process decreases the swelling ratio. The water retention reveals a similar behavior for the different compositions. The swelling characteristics in the presence of different cations and anions in a swelling medium were studied. The hydrogels were also loaded with urea solutions as a model agrochemical and their potential application for controlled release has been investigated. The improve properties of the prepared materials suggested that, the (PVP/CMC) hydrogels can be use in agriculture applications

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

International Nuclear Information System (INIS)

Lahiri, Susanta; Sarkar, Soumi

2007-01-01

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

Polyvinylpyrrolidone/ Poly aniline Composite Based 36 degree YX LiTaO3 Surface Acoustic Wave H2 Gas Sensor

International Nuclear Information System (INIS)

Amir Sidek; Rashidah Arsat; Xiuli, He; Kalantar-zadeh, K.; Wlodarski, W.

2013-01-01

Poly-vinyl-pyrrolidone (PVP)/ poly aniline based surface acoustic wave (SAW) sensors were fabricated and characterized and their performances towards hydrogen gas were investigated. The PVP/ poly aniline fibers composite were prepared by electro spinning of the composite aqueous solution deposited directly onto the active area of SAW transducers. Via scanning electron microscopy (SEM), the morphology of the deposited nano structure material was observed. From the dynamic response, frequency shifts of 6.243 kHz (1% H 2 ) and 8.051 kHz (1% H 2 ) were recorded for the sensors deposited with PVP/ ES and PVP/ EB, respectively. (author)

Effect of solvent evaporation and coagulation on morphology development of asymmetric membranes

Science.gov (United States)

Chandrasekaran, Neelakandan; Kyu, Thein

2008-03-01

Miscibility behavior of blends of amorphous polyamide (PA) and polyvinylpyrrolidone (PVP) was studied in relation to membrane formation. Dimethylsulfoxide (DMSO) and water were used as solvent and non-solvent, respectively. Differential scanning calorimetry and cloud point measurements revealed that the binary PA/PVP blends as well as the ternary PA/PVP/DMSO system were completely miscible at all compositions. However, the addition of non-solvent (water) to this ternary system has led to phase separation. Visual turbidity study was used to establish a ternary liquid-liquid phase diagram of the PA-PVP/DMSO/water system. Scanning Electron Microscopy (SEM) showed the development of finger-like and sponge-like cross sectional morphologies during coagulation. Effects of polymer concentration, PA/PVP blend ratio, solvent/non-solvent quality, and evaporation time on the resulting membrane morphology will be discussed.

Recent Developments in Shape-Controlled Synthesis of Silver Nanocrystals.

Science.gov (United States)

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.

Study of a new method for the evaluation of portal vein pressure by hepatic perfusion imaging

International Nuclear Information System (INIS)

Cheng Muhua; Ling Yunbiao; Pan Zhiheng; Zhang Feng; Chen Weizhen

2002-01-01

To study a new method for predication of portal vein pressure (PVP) by hepatic perfusion imaging. 25 hepato-cirrhotic cases and 13 normal controls were performed the hepatic perfusion imaging. According to two compartmental model the values of portal vein indexes (PVI) was calculated using curve slope, area and hepatic heart perfusion ratio methods etc. The relationship of PVI with different method to PVP was also observed. All PVI by three methods in hepatocirrhosis were higher than those in normal controls (P<0.01), and also positively correlated with the PVP, their correlated coefficients was 0.79, 0.60, 0.68 respectively. Among them the slope method was most markedly significant than normal control and closely correlated with PVP. PVI can sensitively reflect the changes of portal vein blood flow. And it was an atraumatic, simple method for the evaluation of PVP

Percutaneous vertebroplasty and conservative management for the treatment of osteoporotic vertebral fractures: a comparative study

International Nuclear Information System (INIS)

Liu Wengui; Lu Jinyu; Sun Jianhua; Liang Ding; Li Zhiwei; Wang Hesheng; Guo Shanfeng

2011-01-01

Objective: To investigate the better therapeutic measures for painful osteoporotic vertebral compression fractures (OVCF) through comparing the efficacy of percutaneous vertebroplasty (PVP) with that of conservative management. Methods: Forty-three consecutive patients, encountered from December 2009 to December 2010 in authors' hospital, were enrolled in this study. The patients were divided into PVP group (n=22) and conservative group (n=21). Visual analog score (VAS) for pain and Oswestry disability index (ODI) questionnaire scores were assessed before and 1 week, 1, 3, 6, 12 months after the treatment. Patients' activity levels and other information, including complications and new fractures after treatment, were also evaluated. Results: Before the treatment both the VAS and ODI scores showed no statistically significant difference between the two groups. Significant reduction of both VAS and ODI was observed in PVP group at 1 week and at 1 and 3 months after treatment when compared with those in conservative group (P<0.05). Patients' activity levels in PVP group were significantly improved than that in conservative group (P<0.01). One new fracture was observed in the conservative group, while no new fracture was seen in the PVP group. Conclusion: Immediate pain relief and improvement of daily activities after PVP can be achieved in all patients. PVP should be considered as the treatment of first choice for symptomatic osteoporotic vertebral fractures. (authors)

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

Science.gov (United States)

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

2015-01-01

Post traumatic osteonecrosis of a vertebral body occurring in a delayed fashion was first described by the German doctor Kümmell in 1895. Several studies have reported percutaneous vertebroplasty (PVP), or percutaneous kyphoplasty (PKP) for Kümmell's disease achieves good outcomes. However, it is unknown whether a technique is superior for the treatment of this disease. The objective of the study is to compare the efficacy of PVP and PKP for the treatment of Kümmell's disease. A retrospective review was conducted for 73 patients with Kümmell's disease. PVP was performed in 38 patients and PKP in 35 patients. Visual analogue score (VAS) was used to evaluate pain. The anterior vertebral height was measured. The operative time, the incidence of cement leakage and the costs were recorded. In both PVP group and PKP group, the VAS and anterior vertebral height significantly improved at 1-day postoperatively (P 0.05). Between the PVP and PKP groups, there were no significant differences in VAS and the anterior vertebral height at 1-day postoperatively and at the final followup (P > 0.05). The operating time and expense in the PKP group were higher than the PVP group (P pain relief and restoration of vertebral height to PKP for the treatment of Kümmell's disease. PKP has a significant advantage over PVP in term of the fewer cement leakages.

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

Science.gov (United States)

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

2017-09-01

The extensive use and release to the aquatic environment of silver nanoparticles (NPs) could lead to their incorporation into the food web. Brine shrimp larvae of 24h showed low sensitivity to the exposure to PVP/PEI-coated Ag NPs (5nm), with EC 50 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.

Controlled release fertilizers using superabsorbent hydrogel prepared by gamma radiation

International Nuclear Information System (INIS)

Elbarbary, Ahmed M.; Ghobashy, Mohamed Mohamady

2017-01-01

Superabsorbent hydrogels (PVP/CMC) based on polyvinylpyrrolidone (PVP)/carboxylmethyl cellulose (CMC) of different copolymer compositions were prepared by gamma radiation. Factors affecting the gel content (%) and the swelling ratio (g/g) of hydrogel such as irradiation dose as well as copolymer composition were investigated. With increasing the CMC content in PVP/CMC hydrogels, increases the swelling and improves the water retention capability. The high swelling ratio was observed at copolymer composition of PVP/CMC (60/40). Fast swelling of the hydrogels was obtained after 20 min. The effect of different fertilizers and buffers of different pH's on equilibrium swelling of hydrogels was investigated. Fertilizers such as urea, monopotassium-phosphate (MPK), and nitrogen-phosphate-potassium (NPK) were loaded onto the hydrogel to supply nitrogen, potassium and phosphorous nutrients. PVP/CMC hydrogels retained 28-36% after 72 h and slow retention was noticed up to 9 days. The swelling of hydrogel in fertilizer solutions is lower than that in water. The hydrogels showed adsorption desorption of fertilizers which governs by slow release property. The release rate of urea is much higher 10 times than that of phosphate. After 3 days, urea released 60%, while phosphate released 10-12%. The applicability of PVP/CMC hydrogels in the agricultural fields shows greater growth effect on zea maize plants. The growth of zea maize plant in soil mixed with PVP/CMC hydrogels loaded fertilizers is greater than untreated soil. The slow release fertilize, the high swelling and the slow water retention behaviors of PVP/CMC hydrogels encourage their use as safer release systems for fertilizers and as soil conditioner in agricultural applications.

Controlled release fertilizers using superabsorbent hydrogel prepared by gamma radiation

Energy Technology Data Exchange (ETDEWEB)

Elbarbary, Ahmed M.; Ghobashy, Mohamed Mohamady [Atomic Energy Authority, Nasr City (Egypt). National Center for Radiation Research and Technology (NCRTT)

2017-07-01

Superabsorbent hydrogels (PVP/CMC) based on polyvinylpyrrolidone (PVP)/carboxylmethyl cellulose (CMC) of different copolymer compositions were prepared by gamma radiation. Factors affecting the gel content (%) and the swelling ratio (g/g) of hydrogel such as irradiation dose as well as copolymer composition were investigated. With increasing the CMC content in PVP/CMC hydrogels, increases the swelling and improves the water retention capability. The high swelling ratio was observed at copolymer composition of PVP/CMC (60/40). Fast swelling of the hydrogels was obtained after 20 min. The effect of different fertilizers and buffers of different pH's on equilibrium swelling of hydrogels was investigated. Fertilizers such as urea, monopotassium-phosphate (MPK), and nitrogen-phosphate-potassium (NPK) were loaded onto the hydrogel to supply nitrogen, potassium and phosphorous nutrients. PVP/CMC hydrogels retained 28-36% after 72 h and slow retention was noticed up to 9 days. The swelling of hydrogel in fertilizer solutions is lower than that in water. The hydrogels showed adsorption desorption of fertilizers which governs by slow release property. The release rate of urea is much higher 10 times than that of phosphate. After 3 days, urea released 60%, while phosphate released 10-12%. The applicability of PVP/CMC hydrogels in the agricultural fields shows greater growth effect on zea maize plants. The growth of zea maize plant in soil mixed with PVP/CMC hydrogels loaded fertilizers is greater than untreated soil. The slow release fertilize, the high swelling and the slow water retention behaviors of PVP/CMC hydrogels encourage their use as safer release systems for fertilizers and as soil conditioner in agricultural applications.

Comparative Analysis of the Paravertebral Analgesic Pump Catheter with the Epidural Catheter in Elderly Trauma Patients with Multiple Rib Fractures.

Science.gov (United States)

Shapiro, Brian S; Wasfie, Tarik; Chadwick, Mathew; Barber, Kimberly R; Yapchai, Raquel

2017-04-01

Presently, trauma guidelines recommend epidural analgesia as the optimal modality of pain relief from rib fractures. They are not ideally suited for elderly trauma patients and have disadvantages including bleeding risk. The paravertebral analgesic pump (PVP) eliminates such disadvantages and includes ease of placement in the trauma setting. This study compares pain control in patients treated by EPI versus PVP. This is a retrospective, historical cohort study comparing two methods of pain management in the trauma setting. Before 2010, patients who had epidural catheters (EPI) placed for pain control were compared with patients after 2010 in which the PVP was used. All patients had multiple rib fractures as diagnosed by CT scan. Analysis was adjusted for age, number of fractures, and comorbid conditions. Multiple linear regression analysis was conducted to compare average reported pain. A total of 110 patients, 31 PVP and 79 epidural catheters, were included in the study. Overall mean age was 65 years. The mean Injury Severity Score was 12.0 (EPI) and 11.1 (PVP). Mean number rib fractures was 4.29 (EPI) and 4.71 (PVP). PVP was associated with a 30 per cent greater decrease in pain than that seen with EPI (6.0-1.9 vs 6.4-3.4). After controlling for age, Injury Severity Score, and number of rib fractures, there were no differences in intensive care unit or total length of stay (P = 0.35) or in pain score (3.76 vs 3.56, P = 0.64). In conclusion, the PVP compares well with epidural analgesia in older trauma patients yet is safe, well tolerated, and easily inserted.

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

Energy Technology Data Exchange (ETDEWEB)

Xu, G., E-mail: gxu@alum.imr.ac.cn; Wang, X.L.; Liu, G.Z.

2015-02-28

Graphical abstract: - Highlights: • Facile solvothermal synthesis of ZnO nanostructures in super high alkaline alcoholic condition. • The exact role and chemical transformations of PVP in solvothermal synthesis of ZnO nanostructures was revealed. • Mechanism of abnormal growth of ZnO nanopyramids was proposed based on ring-opening reaction of PVP. - Abstract: 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 ({sup 1}H 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.

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

International Nuclear Information System (INIS)

Hashim, K.; Mohid, N.; Bahari, K.; Dahlan, K.Z.

2000-01-01

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

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

Energy Technology Data Exchange (ETDEWEB)

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

2000-03-01

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

A rapid approach for measuring silver nanoparticle concentration and dissolution in seawater by UV-Vis.

Science.gov (United States)

Sikder, Mithun; Lead, Jamie R; Chandler, G Thomas; Baalousha, Mohammed

2018-03-15

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 (λ max ) 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 (λ max ) 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

Inductive effect of poly(vinyl pyrrolidone) on morphology and photocatalytic performance of Bi{sub 2}WO{sub 6}

Energy Technology Data Exchange (ETDEWEB)

Zhang, Qiang; Chen, Jinxing; Xie, Yunyun; Wang, Mozhen; Ge, Xuewu, E-mail: xwge@ustc.edu.cn

2016-04-15

Graphical abstract: - Highlights: • PVP molecular chains will induce the assembly of the primary Bi{sub 2}WO{sub 6} nanosheets. • The assembly of primary Bi{sub 2}WO{sub 6} nanosheets forms various 3D topological structure. • Sheet-like, flower-like, red-blood-cell-like and square-pillar-like Bi{sub 2}WO{sub 6} were formed. • Bi{sub 2}WO{sub 6} formed at low concentration or molecular weight of PVP has better activity. - Abstract: Bi{sub 2}WO{sub 6} has great potential applications in the field of photocatalyst due to its excellent visible-light photocatalytic performance. This work studied the detailed morphological evolution of Bi{sub 2}WO{sub 6} particles synthesized in a simple hydrothermal system induced by the stabilizer poly(vinyl pyrrolidone) (PVP). The XRD and HRTEM results show PVP would not change the crystal structure of Bi{sub 2}WO{sub 6}, but the distribution of PVP on the initially formed Bi{sub 2}WO{sub 6} nanosheets will induce the crystal growth, resulting in a distinct morphology evolution of Bi{sub 2}WO{sub 6} with the increase of the concentration of PVP. At the same time, with the increase of the molecular weight of PVP, the morphology of Bi{sub 2}WO{sub 6} varied from simple sheet-like (S-BWO) to some complicated morphology, such as flower-like (F-BWO), red blood cell-like (B-BWO), and square-pillar-like (SP-BWO). The photocatalytic performances of Bi{sub 2}WO{sub 6} with various morphologies on the decomposition of RhB under visible light irradiation reveal that S-BWO has the best photocatalytic performance, while SP-BWO has the worst. This work not only gives the explanation of the inductive effect of PVP molecular chains on the morphological formation of Bi{sub 2}WO{sub 6} particles, but also provides the controllable way to the preparation of Bi{sub 2}WO{sub 6} with various morphologies taking advantage of the stabilizer PVP.

Preparation of mesoporous titanium dioxide anode by a film- and pore-forming agent for the dye-sensitized solar cell

Energy Technology Data Exchange (ETDEWEB)

Hou, Wenjing; Xiao, Yaoming, E-mail: ymxiao@sxu.edu.cn; Han, Gaoyi, E-mail: han_gaoyis@sxu.edu.cn; 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%).

Combining Sodium Hyaluronate and Polyvinylpyrrolidone Therapies for the Rabbit Cornea: A New Approach to Relief of the Human Dry Eye Syndrome.

Science.gov (United States)

Ehrenberg, Moshe; Zolotariov, Eyal; Loeb, Emmanuel; Poliansky, Vadim; Levy, Aharon

2015-09-01

The novel combination of 0.1% sodium hyaluronate (HA) and 5.0% polyvinylpyrrolidone (PVP) into one eyedrop was investigated to test the hypothesis of its increased relief of dry eye syndrome (DES). We evaluated HA and PVP, either alone, or in combination, by utilizing 16 rabbits, where their right eyes received one or two different eyedrops, and their left eyes, as controls, received none. The DES replica in rabbits was induced by 0.1% benzalkonium chloride (BAC) eyedrops. BAC was instilled into the right eyes of all rabbits, which were divided into four groups of four. In Group 1 M, the rabbits received only BAC. A second eyedrop given to the right eyes of Group 2 M was HA, of Group 3 M was PVP, and of Group 4 M was the combination of both HA and PVP. All eyes were followed clinically for 14 d, and thereafter, examined histopathologically. Clinically, the HA+PVP combination yielded the least perilimbal conjunctival erythema (p eyes in the combination group 4 M displayed the greatest preservation of the corneal epithelium (p < 0.001) and of the perilimbal conjunctival goblet cell density (p < 0.001). This unique combination of both HA and PVP into one eyedrop, was more potent than either treatment alone in protecting the ocular surface. A preparation, containing both HA and PVP may become useful for DES patients.

Study of chemical interaction induced by ionizing radiation poly(dimethylsiloxane-g-ethylene oxide) in the poly(n-vinyl-2-pyrrolidone) and agar membrane; Estudo da interacao quimica do poli(dimetilsiloxano-g-oxido de etileno) na membrana de poli(n-vinil-2-pirrolidona) e agar induzida com radiacao ionizante

Energy Technology Data Exchange (ETDEWEB)

Bazzi, Aurea de Souza

1999-07-01

Membrane composed by poly(N-vinyl-2-pyrrolidone) (PVP) and agar was formulated with and without poly(dimethylsiloxane-g-ethylene oxide) (SEO) irradiated with electron beam with doses between 10-50 kGy. The radiolytic behaviour of each component, PVP, agar and SEO, was studied when irradiated by gamma ray, in the absence and presence of air and water, by electron paramagnetic resonance (EPR) at 77 K. The chemical interaction of SEO with PVP/agar membrane was investigated by: infrared spectroscopy, energy dispersive X-ray fluorescence, dynamic-mechanical analysis, scanning electron microscopy, gel and swelling analysis. The cytotoxicity of the PVP/agar/SEO membrane was evaluated by cellular suppression. The membrane radicals from PVP ({phi}NC.) and from water (H., OH. and H{sub 2}O) was observed by EPR at 77K. The agar radicals formed by hydrogen abstraction of C{sub 1} and C{sub 3} of {beta}-D-galactose and/or C{sub 1} and C{sub 4} of {alpha}-L-galactose, reacted primarily with water radicals in despite of they also took part in the membrane by chemical bond. The radicals from SEO (.CH{sub 2}{approx}, .Si{approx}, .O{approx}) participated in the inter and intramolecular crosslinking as co-crosslinker by polymeric bridge. The co-crosslinked action depended on its concentration associated to PVP concentration. The presence op acrylates increases the tensile break of the PVP/agar/SEO membrane significantly. (author)

Physicochemical and functional properties, microstructure, and storage stability of whey protein/polyvinylpyrrolidone based glue sticks

Directory of Open Access Journals (Sweden)

Guorong Wang

2012-11-01

Full Text Available A glue stick is comprised of solidified adhesive mounted in a lipstick-like push-up tube. Whey is a byproduct of cheese making. Direct disposal of whey can cause environmental pollution. The objective of this study was to use whey protein isolate (WPI as a natural polymer along with polyvinylpyrrolidone (PVP to develop safe glue sticks. Pre-dissolved WPI solution, PVP, sucrose, 1,2-propanediol (PG, sodium stearate, defoamer, and preservative were mixed and dissolved in water at 90 oC and then molded in push-up tubes. Chemical composition, functional properties (bonding strength, glue setting time, gel hardness, extension/retraction, and spreading properties, microstructure, and storage stability of the prototypes were evaluated in comparison with a commercial control. Results showed that all WPI/PVP prototypes had desirable bonding strength and exhibited faster setting than PVP prototypes and control. WPI could reduce gel hardness and form less compact and rougher structures than that of PVP, but there was no difference in bonding strength. PVP and sucrose could increase the hygroscopicity of glue sticks, thus increasing storage stability. Finally, the optimized prototype GS3 (major components: WPI 8.0%, PVP 12.0%, 1,2-propanediol 10.0%, sucrose 10.0%, and stearic sodium 7.0% had a comparable functionality to the commercial control. Results indicated that whey protein could be used as an adhesive polymer for glue stick formulations, which could be used to bond fiber or cellulose derived substrates such as paper.

Stability Study of Flexible 6,13-Bis(triisopropylsilylethynylpentacene Thin-Film Transistors with a Cross-Linked Poly(4-vinylphenol/Yttrium Oxide Nanocomposite Gate Insulator

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Jin-Hyuk Kwon

2016-03-01

Full Text Available We investigated the electrical and mechanical stability of flexible 6,13-bis(triisopropylsilylehtynylpentacene (TIPS-pentacene thin-film transistors (TFTs that were fabricated on polyimide (PI substrates using cross-linked poly(4-vinylphenol (c-PVP and c-PVP/yttrium oxide (Y2O3 nanocomposite films as gate insulators. Compared with the electrical characteristics of TIPS-pentacene TFTs with c-PVP insulators, the TFTs with c-PVP/Y2O3 nanocomposite insulators exhibited enhancements in the drain current and the threshold voltage due to an increase in the dielectric capacitance. In electrical stability experiments, a gradual decrease in the drain current and a negative shift in the threshold voltage occurred during prolonged bias stress tests, but these characteristic variations were comparable for both types of TFT. On the other hand, the results of mechanical bending tests showed that the characteristic degradation of the TIPS-pentacene TFTs with c-PVP/Y2O3 nanocomposite insulators was more critical than that of the TFTs with c-PVP insulators. In this study, the detrimental effect of the nanocomposite insulator on the mechanical stability of flexible TIPS-pentacene TFTs was found to be caused by physical adhesion of TIPS-pentacene molecules onto the rough surfaces of the c-PVP/Y2O3 nanocomposite insulator. These results indicate that the dielectric and morphological properties of polymeric nanocomposite insulators are significant when considering practical applications of flexible electronics operated at low voltages.

The silver nanowires synthesized using different molecule weight of polyvinyl pyrrolidone for controlling diameter and length by one-pot polyol method

Energy Technology Data Exchange (ETDEWEB)

Junaidi, E-mail: junaidi.1982@fmipa.unila.ac.id [Departement of Physics, Universitas Gadjah Mada, Yogyakarta, 55281 (Indonesia); Departement of Physics, Lampung University, Bandar Lampung (Indonesia); Triyana, K., E-mail: triyana@ugm.ac.id; Suharyadi, E.; Harsojo [Departement of Physics, Universitas Gadjah Mada, Yogyakarta, 55281 (Indonesia); Nanomaterials Research Group, Universitas Gadjah Mada, Yogyakarta, 55281 (Indonesia); Hui, H.; Wu, L. Y. L., E-mail: ylwu@simtech.a-star.edu.sg [Singapore Institute of Manufacturing Technology, 71 Nanyang Drive, Singapore 638075 (Singapore)

2016-06-17

In this paper, we report our investigation on the effect of the molecular weight and molar ratio of polyvinyl pyrrolidone (PVP) and silver nitrate (AgNO{sub 3}) for controlling diameter and length of the silver nanowires synthesized with a high-aspect-ratio. The silver nanowires synthesized by one-pot polyol method at a constant temperature oil bath of 130°C. Different molecule weights of PVP, i.e. 55 K, 360 K, and 1300 K were used combined with different molar ratios of [PVP:Ag]. The UV–vis spectrophotometry and Field-emission scanning electron microscopy (FE-SEM) were employed to characterize the silver nanowires. The results show that the molecular weight and molar ratio of [PVP:Ag] are very important for controlling growth and properties of the silver nanowires. The diameter and length of silver nanowires are obtained 80 to 140 nm and 30 to 70 µm, respectively. The higher molecular weight of PVP, the greater diameter and length of silver nanowires.

Synthesis and characterization of core-shell gold nanoparticles with poly(vinyl pyrrolidone) from a new precursor salt

Science.gov (United States)

Behera, M.; Ram, S.

2013-02-01

In this article, we report a facile one-step chemical synthesis of gold (Au) nanoparticles (GNPs) from a new precursor salt i.e., gold hydroxide in the presence of poly(vinyl pyrrolidone) (PVP) polymer. The non-aqueous dispersion of GNPs was comprehensively characterized by UV-Visible, FTIR, zeta potential, and transmission electron microscope (TEM). A strong surface plasmon resonance band at 529 nm in the UV-Visible spectrum confirms the formation of GNPs in the Au colloid. The FTIR spectroscopic results showed that PVP molecules get chemisorbed onto the surface of GNP via O-atom of carbonyl group. A negative zeta potential of (-)16 mV reveals accumulation of nonbonding electrons of O-atom of carbonyl group of PVP molecules on the nanosurface of GNP. TEM images demonstrate a core-shell nanostructure with an Au-crystalline core covered by a thin amorphous PVP-shell. PVP-capped GNPs could be a potential candidate for bio-sensing, catalysis, and other applications.

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

Science.gov (United States)

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

2013-12-01

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

The silver nanowires synthesized using different molecule weight of polyvinyl pyrrolidone for controlling diameter and length by one-pot polyol method

International Nuclear Information System (INIS)

Junaidi; Triyana, K.; Suharyadi, E.; Harsojo; Hui, H.; Wu, L. Y. L.

2016-01-01

In this paper, we report our investigation on the effect of the molecular weight and molar ratio of polyvinyl pyrrolidone (PVP) and silver nitrate (AgNO 3 ) for controlling diameter and length of the silver nanowires synthesized with a high-aspect-ratio. The silver nanowires synthesized by one-pot polyol method at a constant temperature oil bath of 130°C. Different molecule weights of PVP, i.e. 55 K, 360 K, and 1300 K were used combined with different molar ratios of [PVP:Ag]. The UV–vis spectrophotometry and Field-emission scanning electron microscopy (FE-SEM) were employed to characterize the silver nanowires. The results show that the molecular weight and molar ratio of [PVP:Ag] are very important for controlling growth and properties of the silver nanowires. The diameter and length of silver nanowires are obtained 80 to 140 nm and 30 to 70 µm, respectively. The higher molecular weight of PVP, the greater diameter and length of silver nanowires.

Evaluation of morphology and cell behaviour of a novel synthesized electrospun poly(vinyl pyrrolidone/poly(vinyl alcohol/hydroxyapatite nanofibers

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Raheleh Faridi-Majidi

2017-04-01

Full Text Available Objective(s: Three-dimensional structures such as nanofibrous scaffolds are being used in biomedical engineering as well as provide a site for cells to attach and proliferate leading to tissue formation. In the present study, poly(vinyl pyrrolidone (PVP/ poly(vinyl alcohol(PVA hybrid nanofibrous scaffold was synthesized by electrospinning. Materials and Methods: The effect of adding nano hydroxyapatite (n-HA and also Epoxypropoxy-propyl-trimethoxysilane (EPPTMS as a crosslinking agent on morphology and cell behaviour of the nanofibers was investigated.Results: Scanning electron microscope (SEM observations showed that all kinds of nanofibers represented uniform and well-ordered morphologies without formation of any beads by controlling the synthesis parameters. The average ûber diameter of PVP-PVA was 260 nm. n-HA was synthesized by wet chemical process. The synthesized n-HA was characterized by XRD for structural analysis. Transmission electron microscope (TEM revealed that HA particles had nanosized dimensions (in the range of 40-100 nm. The presence of n-HA within electrospun PVP-PVA nanofibers was confirmed by XRD and Fourier transmission infrared spectroscopy (FTIR analyses. The average ûber diameter was decreased to 136 nm when n-HA was added in the composition of PVP-PVA. FTIR analysis depicted that PVP-PVA nanofibers were linked to EPPTMS as a biocompatible material by the covalent bond. Although adding n-HA caused to decrease the diameter of PVP-PVA nanofibers, addition of EPPTMS within PVP/PVA/n-HA nanofibers induced increasing distribution of fiber diameter as it enhanced to 195nm. In addition, the proper proliferation of G292 osteoblastic cells without any cytotoxicity was observed for the nanofiber.Conclusion: Since these materials have been known as biomaterials, PVP/PVA/n-HA-EPPTMS nanofibers can be propounded as a good candidate for bone tissue engineering application.

Investigation of the potential of polymer-bound co-ordination compounds as catalysts for the photolytic production of hydrogen from water. Final report

Energy Technology Data Exchange (ETDEWEB)

Kelly, J M; Clear, J M; Grayson, D H; Johnston, D S; Pepper, D C; Vos, J G

1981-01-01

Organic polymers containing polymer-bound complexes of the type (Ru(bpy)/sub 2/(PVP)X)/sup n+/ (n=1, X=Cl; n=2, X=CO,py,H/sub 2/O,PVP) have been prepared. Synthetic routes proceed either from preformed polymer and Ru(bpy)/sub 2/Cl/sub 2/ or (Ru(bpy)/sub 2/(OH/sub 2/)/sub 2/)/sup 2 +/ or via polymerization of the corresponding monomer complex. The dependence of the chemical and physical properties on the nature of the polymer backbone and on the loading of the metal complex on the polymer (the Ru:PVP) ratio has been studied. The complexes prepared from homo-PVP are soluble in methanol and aqueous acid but not in neutral water. Water-soluble complexes may be prepared from water-soluble copolymers. (Ru(bpy)/sub 2/(PVP)Cl)/sup +/ and (Ru(bpy)/sub 2/(PVP)/sub 2/)/sup 2 +/ luminesce strongly in methanol at 77/sup 0/K but not at room temperature. Their behavior upon irradiation in methanol solution is similar to that of the pyridine complexes (Ru(bpy)/sub 2/(py)X)/sup n+/ which undergo photosubstitution and photoanation. The rate and extent of these reactions, which eventually lead to removal of the complex from the polymer backbone, are sensitive to the Ru:PVP ratio, and evidence has been found for intrachain recombination of the (Ru(bpy)/sub 2/X)/sup n+/ fragment with the polymer. This leads to enhanced photostability of the polymer. The water-soluble (Ru(bpy)/sub 2/(PVP)(OH/sub 2/))/sup 2 +/ is rather photostable. Water-insoluble films of the polymeric complexes may be cast on glass slides. Under these conditions they are luminescent at room temperature. They are quite photostable upon irradiation, even in water, and there is little tendency for dissociation of the metal complex from the polymer.

Antisolvent precipitation technique: A very promising approach to crystallize curcumin in presence of polyvinyl pyrrolidon for solubility and dissolution enhancement.

Science.gov (United States)

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. Copyright © 2016

Diffusion-Weighted Imaging for Predicting New Compression Fractures Following Percutaneous Vertebroplasty

International Nuclear Information System (INIS)

Sugimoto, T.

2008-01-01

Background: Percutaneous vertebroplasty (PVP) is a technique that structurally stabilizes a fractured vertebral body. However, some patients return to the hospital due to recurrent back pain following PVP, and such pain is sometimes caused by new compression fractures. Purpose: To investigate whether the apparent diffusion coefficient (ADC) of adjacent vertebral bodies as assessed by diffusion-weighted imaging before PVP could predict the onset of new compression fractures following PVP. Material and Methods: 25 patients with osteoporotic compression fractures who underwent PVP were enrolled in this study. ADC was measured for 49 vertebral bodies immediately above and below each vertebral body injected with bone cement before and after PVP. By measuring ADC for each adjacent vertebral body, ADC was compared between vertebral bodies with a new compression fracture within 1 month and those without new compression fractures. In addition, the mean ADC of adjacent vertebral bodies per patient was calculated. Results: Mean preoperative ADC for the six adjacent vertebral bodies with new compression fractures was 0.55x10 -3 mm 2 /s (range 0.36-1.01x10 -3 mm 2 /s), and for the 43 adjacent vertebral bodies without new compression fractures 0.20x10 -3 mm 2 /s (range 0-0.98x10 -3 mm 2 /s) (P -3 mm 2 /s (range 0.21-1.01x10 -3 mm 2 /s), and that for the 19 patients without new compression fractures 0.17x10 -3 mm 2 /s (range 0.01-0.43x10 -3 mm 2 /s) (P<0.001). Conclusion: The ADC of adjacent vertebral bodies as assessed by diffusion-weighted imaging before PVP might be one of the predictors for new compression fractures following PVP

Day care bipolar transurethral resection vs photoselective vaporisation under sedoanalgesia: A prospective, randomised study of the management of benign prostatic hyperplasia

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Rajeev Sood

2017-12-01

Full Text Available Objective: To conduct a prospective randomised study comparing the safety, effectiveness and treatment outcomes in patients undergoing bipolar transurethral resection of the prostate (bTURP and photoselective vaporisation of the prostate (PVP under sedoanalgesia, as sedoanalgesia is a safe and effective technique suitable for minimally invasive endourological procedures and although studies have confirmed that both TURP and PVP are feasible under sedoanalgesia there are none comparing the two. Patients and methods: Between November 2014 and April 2016, all patients satisfying the eligibility criteria underwent either bTURP or PVP under sedoanalgesia after randomisation. The groups were compared for functional outcomes, visual analogue scale (VAS pain scores (range 0–10, perioperative variables and complications, with a follow-up of 3 months. Results: In all, 42 and 36 patients underwent bTURP and PVP under sedoanalgesia, respectively. The mean VAS pain score was <2 at any time during the procedure, with no conversions to general anaesthesia. PVP patients had a shorter operating time [mean (SD 55.64 (12.8 vs 61.79 (14.2 min, P = 0.035], shorter duration of hospitalisation [mean (SD 14.58 (2.81 vs 19.21 (2.82 h, P < 0.001] and a higher dysuria rate when compared to bTURP patients. However, the catheterisation time was similar and both intraoperative and postoperative complications were minimal and comparable. Improvements in the International Prostate Symptom Score, quality of life, prostate volume, maximum urinary flow rate and post-void residual urine volume at 3 months were similar in both groups. None of our patients required re-admission or re-operation. Conclusion: Both PVP and bTURP can be carried out safely under sedoanalgesia with excellent treatment outcomes. Keywords: Photoselective vaporisation of prostate (PVP, Bipolar TURP, Day care bTURP, Day care PVP, Sedoanalgesia

Inclusion complex and nanoclusters of cyclodextrin to increase the solubility and efficacy of albendazole.

Science.gov (United States)

Pacheco, P A; Rodrigues, L N C; Ferreira, J F S; Gomes, A C P; Veríssimo, C J; Louvandini, H; Costa, R L D; Katiki, L M

2018-03-01

Albendazole (ABZ), a benzimidazole widely used to control gastrointestinal parasites, is poorly soluble in water, resulting in variable and incomplete bioavailability. This has favored the appearance ABZ-resistant nematodes and, consequently, an increase in its clinical ineffectiveness. Among the pharmaceutical techniques developed to increase drug efficacy, cyclodextrins (CDs) and other polymers have been extensively used with water-insoluble pharmaceutical drugs to increase their solubility and availability. Our objective was to prepare ABZ formulations, including β-cyclodextrin (βCD) or hydroxypropyl-β-cyclodextrin (HPβCD), associated or not to the water-soluble polymer polyvinylpyrrolidone (PVP). These formulations had their solubility and anthelmintic effect both evaluated in vitro. Also, their anthelmintic efficacy was evaluated in lambs naturally infected with gastrointestinal nematodes (GIN) through the fecal egg count (FEC) reduction test. In vitro, the complex ABZ/HPβCD had higher solubility than ABZ/βCD. The addition of PVP to the complexes increased solubility and dissolution rates more effectively for ABZ/HPβCD than for ABZ/βCD. In vivo, 48 lambs naturally infected with GIN were divided into six experimental groups: control, ABZ, ABZ/βCD, ABZ/βCD-PVP, ABZ/HPβCD, and ABZ/HPβCD-PVP. Each treated animal received 10 mg/kg of body weight (based on the ABZ dose) for three consecutive days. After 10 days of the last administered dose, treatment efficacy was calculated. The efficacy values were as follows: ABZ (70.33%), ABZ/βCD (85.33%), ABZ/βCD-PVP (82.86%), ABZ/HPβCD (78.37%), and ABZ/HPβCD-PVP (43.79%). In vitro, ABZ/HPβCD and ABZ/HPβCD-PVP had high solubility and dissolution rates. In vivo, although the efficacies of ABZ/βCD, ABZ/βCD-PVP, and ABZ/HPβCD increased slightly when compared to pure ABZ, this increase was not significant (P > 0.05).

Investigation of nanocomposites made with poly(methacrylic acid-co-methyl methacrylate/poly(N-vinyl-2-pyrrolidone/multi-walled carbon nanotubes

Directory of Open Access Journals (Sweden)

Liu Guoqin

2014-01-01

Full Text Available Poly(methacrylic acid-co-methyl methacrylate (P(MAA-co-MMA was prepared in the presence of poly(N-vinyl-2-pyrrolidone (PVP and multiwalled carbon nanotubes (MWNTs via ultrasonic assisted solution free radical polymerization, i.e., P(MAA-co-MMA/PVP/MWNTs nanocomposites. The morphology, glassy-state storage modulus, thermal behavior and swelling characteristics of P(MAA-co-MMA/PVP/MWNTs nanocomposites were investigated. Scanning electron micrographs (SEM revealed that MWNTs at low concentration could be uniformly dispersed into P(MAA-co-MMA/PVP blends. With increasing MWNTs weight fraction, the average glassy-state modulus, glass transition temperatures and decomposition temperature of the nanocomposites increased, but their swelling characteristics decreased.

Investigation of nanocomposites made with poly(methacrylic acid-co-methyl methacrylate)/poly(N-vinyl-2-pyrrolidone)/multi-walled carbon nanotubes

Energy Technology Data Exchange (ETDEWEB)

Guoqin, Liu; Wei, Miao [College of Material Science and Engineering, Henan University of Technology (China); Lin-Jian, Shangguan, E-mail: mikepolymer@126.com [School of Mechanical Engineering, North China University of Water Conservancy and Electric Power (China)

2014-06-01

Poly(methacrylic acid-co-methyl methacrylate) (P(MAA-co-MMA)) was prepared in the presence of poly(N-vinyl-2-pyrrolidone) (PVP) and multi-walled carbon nanotubes (MWNTs) via ultrasonic assisted solution free radical polymerization, i.e., P(MAA-co-MMA)/PVP/MWNTs nanocomposites. The morphology, glassy-state storage modulus, thermal behavior and swelling characteristics of P(MAA-co-MMA)/PVP/MWNTs nanocomposites were investigated. Scanning electron micrographs (SEM) revealed that MWNTs at low concentration could be uniformly dispersed into P(MAA-co-MMA)/PVP blends. With increasing MWNTs weight fraction, the average glassy-state modulus, glass transition temperatures and decomposition temperature of the nanocomposites increased, but their swelling characteristics decreased. (author)

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

International Nuclear Information System (INIS)

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 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

Dual phase helical CT versus portal venous phase CT for the detection of colorectal liver metastases: Correlation with intra-operative sonography, surgical and pathological findings

International Nuclear Information System (INIS)

Scott, D. John; Guthrie, J. Ashley; Arnold, Paul; Ward, Janice; Atchley, Julian; Wilson, Daniel; Robinson, Philip J.

2001-01-01

AIM: To assess whether dual phase helical computed tomography (DPCT) of the liver improves the detection of colorectal liver metastases compared with portal venous phase (PVP) imaging alone. MATERIALS AND METHODS: DPCT was performed in 33 consecutive patients before laparotomy for resection of colorectal liver metastases. CT comprised 8-mm slice collimation with a pitch of 1 to 1.25; imaging was commenced 20-25 and 65-70 s after the start of injection of 150 ml of contrast medium at 5 ml/s to coincide with hepatic arterial phase (HAP) and PVP contrast enhancement, respectively. Four blinded observers independently reviewed the HAP, PVP and DPCT images recording the site and size of all lesions. Alternative-free response receiver operating characteristic (AFROC) methodology was used to analyse the results, which were correlated with surgery, intra-operative ultrasound and histology. RESULTS: The mean observer sensitivities for malignant lesion detection were 75.3% for DPCT, 69.7% for PVP imaging and 66.7% for HAP imaging alone. There was a statistically significant improvement in malignant lesion detection using DPCT when compared with PVP imaging alone (P < 0.05). The mean areas under the AFROC curves were 0.84 for DPCT and 0.82 for PVP (P < 0.03) imaging alone. CONCLUSION: The detection of colorectal liver metastases was marginally better with DPCT than with PVP imaging alone, but the discovery of additional lesions did not affect the management of any of the patients in this study. Scott, D.J. et al. (2001)

Composite Membranes Based on Polyether Sulfone

Directory of Open Access Journals (Sweden)

A. Soroush

2010-12-01

Full Text Available The role of polymeric additives such as PVP and PEG is studied with respect to the morphology of PES porous layer as a sublayer of nanofiltration composite membranes based on PES/PA. Results show that by phase inversionprocess of quaternary systems comprised of four components of polymer/solvent/non-solvent/additive and the diffusion of intertwined polymers some changes occur in membrane morphology with changes in their concentration. With addition of PVP, tear-like pores, finger-like and channel-like morphology change to enlarged channel cavities and by adding more PVP, membrane morphology changes further and spongy regions are extended in the membrane. Presence of PEG in casting solution delayed the precipitation time. By adding PEG, the solution viscosity is increased which is followed by decreases in diffusion rates of solvent/non-solvent in coagulation bath.Therefore, membrane morphology shifts to small pores and spongier region. Another effect of increased PEG content would be deformed PA layer formation in PES sublayer which affects membrane performance. However, PVP as an additive does not change membrane salt rejection very much while it leads to higher fluxes. A membrane with 2.5 percent PVP would perform by 40 percent flux increases, while a membrane with 5% PVP shows flux reductions even below the initial value. Contrary to PVP, the PEG content of 20 percent leads to 4 folds flux increases and in a membrane with 50 percent PEG, there is a flux increase by 7 folds and drop in salt rejection occurs by 50 percent and 70 percent, respectively.

Utilization of natural polysaccharides by radiation in Korea

International Nuclear Information System (INIS)

Lee, Young Keun; Young Chang Nho

2001-01-01

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

In-vivo optical detection of cancer using chlorin e6 – polyvinylpyrrolidone induced fluorescence imaging and spectroscopy

International Nuclear Information System (INIS)

Chin, William WL; Thong, Patricia SP; Bhuvaneswari, Ramaswamy; Soo, Khee Chee; Heng, Paul WS; Olivo, Malini

2009-01-01

Photosensitizer based fluorescence imaging and spectroscopy is fast becoming a promising approach for cancer detection. The purpose of this study was to examine the use of the photosensitizer chlorin e6 (Ce6) formulated in polyvinylpyrrolidone (PVP) as a potential exogenous fluorophore for fluorescence imaging and spectroscopic detection of human cancer tissue xenografted in preclinical models as well as in a patient. Fluorescence imaging was performed on MGH human bladder tumor xenografted on both the chick chorioallantoic membrane (CAM) and the murine model using a fluorescence endoscopy imaging system. In addition, fiber optic based fluorescence spectroscopy was performed on tumors and various normal organs in the same mice to validate the macroscopic images. In one patient, fluorescence imaging was performed on angiosarcoma lesions and normal skin in conjunction with fluorescence spectroscopy to validate Ce6-PVP induced fluorescence visual assessment of the lesions. Margins of tumor xenografts in the CAM model were clearly outlined under fluorescence imaging. Ce6-PVP-induced fluorescence imaging yielded a specificity of 83% on the CAM model. In mice, fluorescence intensity of Ce6-PVP was higher in bladder tumor compared to adjacent muscle and normal bladder. Clinical results confirmed that fluorescence imaging clearly captured the fluorescence of Ce6-PVP in angiosarcoma lesions and good correlation was found between fluorescence imaging and spectral measurement in the patient. Combination of Ce6-PVP induced fluorescence imaging and spectroscopy could allow for optical detection and discrimination between cancer and the surrounding normal tissues. Ce6-PVP seems to be a promising fluorophore for fluorescence diagnosis of cancer

[Effect of different bone cement dispersion types in the treatment of osteoporotic vertebral compression fracture].

Science.gov (United States)

Zhao, Yong-Sheng; Li, Qiang; Li, Qiang; Zheng, Yan-Ping

2017-05-25

To observe different bone cement dispersion types of PVP, PKP and manipulative reduction PVP and their effects in the treatment of senile osteoporotic vertebral compression fractures and the bone cement leakage rate. The clinical data of patients with osteoporotic vertebral compression fractures who underwent unilateral vertebroplasty from January 2012 to January 2015 was retrospectively analyzed. Of them, 56 cases including 22 males and 34 females aged from 60 to 78 years old were treated by PVP operation; Fouty-eight cases including 17 males and 31 females aged from 61 to 79 years old were treated by PKP operation; Forty-three cases including 15 males and 28 females aged from 60 to 76 years old were treated by manipulative reduction PVP operation. AP and lateral DR films were taken after the operation; the vertebral bone cement diffusion district area and mass district area were calculated with AutoCAD graphics processing software by AP and lateral DR picture, then ratio(K) of average diffusion area and mass area were calculated, defining K100% as diffusion type. Different bone cement dispersion types of PVP, PKP and manipulative reduction PVP operation were analyzed. According to bone cement dispersion types, patients were divided into diffusion type, mixed type and mass type groups.Visual analogue scale (VAS), vertebral body compression rate, JOA score and bone cement leakage rate were observed. All patients were followed up for 12-24 months with an average of 17.2 months. There was significant difference in bone cement dispersion type among three groups ( P <0.05). The constituent ratio of diffusion type, mixed type and mass type in PVP operation was 46.43%, 35.71%, 17.86%, in PKP was 16.67%, 37.50% , 45.83%, and in manipulative reduction PVP was 37.21%, 44.19% and 18.60%, respectively. PVP operation and manipulative reduction PVP were mainly composed of diffusion type and mixed type, while PKP was mainly composed of mass type and mixed type. There was no

Correlation between central venous pressure and peripheral venous pressure with passive leg raise in patients on mechanical ventilation.

Science.gov (United States)

Kumar, Dharmendra; Ahmed, Syed Moied; Ali, Shahna; Ray, Utpal; Varshney, Ankur; Doley, Kashmiri

2015-11-01

Central venous pressure (CVP) assesses the volume status of patients. However, this technique is not without complications. We, therefore, measured peripheral venous pressure (PVP) to see whether it can replace CVP. To evaluate the correlation and agreement between CVP and PVP after passive leg raise (PLR) in critically ill patients on mechanical ventilation. Prospective observational study in Intensive Care Unit. Fifty critically ill patients on mechanical ventilation were included in the study. CVP and PVP measurements were taken using a water column manometer. Measurements were taken in the supine position and subsequently after a PLR of 45°. Pearson's correlation and Bland-Altman's analysis. This study showed a fair correlation between CVP and PVP after a PLR of 45° (correlation coefficient, r = 0.479; P = 0.0004) when the CVP was correlation was good when the CVP was >10 cmH2O. Bland-Altman analysis showed 95% limits of agreement to be -2.912-9.472. PVP can replace CVP for guiding fluid therapy in critically ill patients.

Replacement of Poly(vinyl pyrrolidone) by Thiols: A Systematic Study of Ag Nanocube Functionalization by Surface-Enhanced Raman Scattering.

Science.gov (United States)

Moran, Christine H; Rycenga, Matthew; Zhang, Qiang; Xia, Younan

2011-11-10

In this work, we used surface-enhanced Raman scattering (SERS) to monitor the replacement of poly(vinyl pyrrolidone) (PVP) on Ag nanocubes by cysteamine, thiol-terminated PEG, and benzenedithiol. PVP is widely used as a colloidal stabilizer and capping agent to control the shape of Ag (as well as many other noble metals) nanocrystals during synthesis, and to stabilize the final colloidal suspension. However, the surface chemistry of Ag nanocrystals often needs to be tailored for specific applications, so the PVP coating must be removed and/or replaced by other ligands. By monitoring the signature peak from the carbonyl groups of PVP, we show, for the first time, that the PVP adsorbed on the surface of Ag nanocubes was completely replaced by the thiol molecules at room temperature over the course of a few hours. We observed the same trend no matter if the Ag nanocubes were suspended in an aqueous solution of the thiol or supported on a silicon substrate and then immersed in the thiol solution.

Synthesis and optical properties of CdS/ZnS coreshell nanoparticles

International Nuclear Information System (INIS)

Saraswathi Amma, B.; Manzoor, K.; Ramakrishna, K.; Pattabi, Manjunatha

2008-01-01

Synthesis and optical properties of manganese (Mn 2+ )-doped, polyvinyl pyrrolidone (PVP)-capped cadmium sulphide (CdS) nanoparticles coated with zinc sulphide (ZnS) are reported. Colloidal solution of Mn 2+ -doped CdS nanoparticles capped with PVP is synthesized using methanol as solvent. PVP is used to control the particle size and to prevent agglomeration. Mn 2+ doping is expected to help in increasing the CdS band edge photoluminescence (PL) emission. Addition of zinc nitrate and sodium sulphide alternately to the Mn 2+ -doped, PVP-stabilized CdS colloid led to the formation of ZnS-coated CdS coreshell nanoparticles. Photoluminescence emission spectra recorded for (CdS-PVP)Mn nanoparticles showed two emission peaks, one at 416 nm and the other weaker peak at 586 nm which is attributed to Mn 2+ emission. Intensity of Mn 2+ peak increased with increase in the Mn 2+ content. Mn 2+ emission disappears when ZnS is coated over the CdS core, resulting in pure CdS band edge emission

Interpolymer complexation: comparisons of bulk and interfacial structures.

Science.gov (United States)

Cattoz, Beatrice; de Vos, Wiebe M; Cosgrove, Terence; Crossman, Martin; Espidel, Youssef; Prescott, Stuart W

2015-04-14

The interactions between the strong polyelectrolyte sodium poly(styrenesulfonate), NaPSS, and the neutral polymer poly(vinylpyrrolidone), PVP, were investigated in bulk and at the silica/solution interface using a combination of diffusion nuclear magnetic resonance spectroscopy (NMR), small-angle neutron scattering (SANS), solvent relaxation NMR, and ellipsometry. We show for the first time that complex formation occurs between NaPSS and PVP in solution; the complexes formed were shown not to be influenced by pH variation, whereas increasing the ionic strength increases the complexation of NaPSS but does not influence the PVP directly. The complexes formed contained a large proportion of NaPSS. Study of these interactions at the silica interface demonstrated that complexes also form at the nanoparticle interface where PVP is added in the system prior to NaPSS. For a constant PVP concentration and varying NaPSS concentration, the system remains stable until NaPSS is added in excess, which leads to depletion flocculation. Surface complex formation using the layer-by-layer technique was also reported at a planar silica interface.

Rheological properties of poly (vinylpiyrrolidone) as a function of average molecular weight and its applications

DEFF Research Database (Denmark)

Marani, Debora; Sudireddy, Bhaskar Reddy; Kiebach, Ragnar

Polyvinylpyrrolidone (PVP) is an attractive material due to its solubility in aqueous and organic solvents, excellent film forming capability, and its ability to act as a dispersant in colloidal suspensions and slurries. These characteristics of PVP have led to its use in a large variety of formu......Polyvinylpyrrolidone (PVP) is an attractive material due to its solubility in aqueous and organic solvents, excellent film forming capability, and its ability to act as a dispersant in colloidal suspensions and slurries. These characteristics of PVP have led to its use in a large variety...... of formulations for pharmaceutics, food, personal care, or coatings, paintings, and printing applications. It is also widely used as organic additive, i.e. dispersant for ceramics. Regardless of the application, the control over the polymer behavior in solution is required for an efficient optimization......, which is the inherent ability of a solute to increase the viscosity of a solvent, used in the MHS equation, has been evaluated via the dilution method. The knowledge obtained from this fundamental study on PVP behavior, has been successfully applied to different case studies....

Assimilation of NH₄Br in Polyvinyl Alcohol/Poly(N-vinyl pyrrolidone) Polymer Blend-Based Electrolyte and Its Effect on Ionic Conductivity.

Science.gov (United States)

Parameswaran, V; Nallamuthu, N; Devendran, P; Manikandan, A; Nagarajan, E R

2018-06-01

Biodegradable polymer blend electrolyte based on ammonium based salt in variation composition consisting of PVA:PVP were prepared by using solution casting technique. The obtained films have been analyzed by various technical methods like as XRD, FT-IR, TG-DSC, SEM analysis and impedance spectroscopy. The XRD and FT-IR analysis exposed the amorphous nature and structural properties of the complex formation between PVA/PVP/NH4Br. Impedance spectroscopy analysis revealed the ionic conductivity and the dielectric properties of PVA/PVP/NH4Br polymer blend electrolyte films. The maximum ionic conductivity was determined to be 6.14 × 10-5 Scm-1 for the composition of 50%PVA: 50%PVP: 10% NH4Br with low activation energy 0.3457 eV at room temperature. Solid state battery is fabricated using highest ionic conducting polymer blend as electrolyte with the configuration Zn/ZnSO4 · 7H2O (anode) ∥ 50%PVA: 50%PVP: 10% NH4Br ∥ Mn2O3 (cathode). The observed open circuit voltage is 1.2 V and its performance has been studied.

Effect of polyvinylpyrrolidone and sodium lauroyl isethionate on kaolinite suspension in an aqueous phase.

Science.gov (United States)

Kwan, Chang-Chin; Chu, Wen-Hweu; Shimabayashi, Saburo

2006-08-01

Suspension of concentrated kaolinite (20 g/30 ml-medium) in the presence of polyvinylpyrrolidone (PVP) and sodium lauroyl isethionate (SLI) was allowed to evaluate its degree of dispersion based on their rheological studies. Flow curves at low shear rate, measured by means of cone-plate method, showed a non-Newtonian flow. Plastic viscosity and Bingham yield value were derived from the flow curves. Relative viscosity, effective volume fraction and void fraction of secondary particle were also obtained. Results of dispersity and fluidity of the suspension were explained. PVP acted as a flocculant at a concentration lower than 0.1% but as a dispersant at a higher concentration. The presence of SLI could decrease both the Bingham yield value and suspension viscosity. Cooperative and competitive effects of PVP and SLI were found. Results indicated that SLI enhanced the degree of dispersion of kaolinite when PVP was less than 0.1%. The suspension, however, showed a maximum flocculation (i.e., aggregation) at 4 mM SLI when the concentration of PVP was higher than 0.1%.

Comparison of percutaneous vertebroplasty with and without interventional tumor removal for spinal metastatic tumor without epidural involvement

Directory of Open Access Journals (Sweden)

Yan Su

2017-03-01

Conclusions: The combination of PVP+ITR is a safe and effective procedure, capable of providing significantly greater pain relief and vertebral stability than PVP alone in patients with malignant vertebral compression fractures.

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

Science.gov (United States)

Aslan, M.; Weingarth, D.; Herbeck-Engel, P.; Grobelsek, I.; Presser, V.

2015-04-01

Mixtures of polyvinylpyrrolidone/polyvinyl butyral (PVP/PVB) are attractive binders for the preparation of carbon electrodes for aqueous electrolyte supercapacitors. The use of PVP/PVB offers several key advantages: They are soluble in ethanol and can be used to spray coat or drain cast activated carbon (AC) electrodes directly on a current collector. Infrared spectroscopy and contact angle measurements show that the PVP-to-PVB ratio determines the degree of binder hydrophilicity. Within our study, the most favorable performance was obtained for AC electrodes with a composition of AC + 1.5 mass% PVP + 6.0 mass% PVB; such electrodes were mechanically stabile and water resistant with a PVP release of less than 5% of total PVP while PVB itself is water insoluble. Compared to when using PVDF, the specific surface area (SSA) of the assembled electrodes was 10% higher, indicating a reduced pore blocking tendency. A good electrochemical performance was observed in different aqueous electrolytes for composite electrodes with the optimized binder composition: 160 F g-1 at 1 A g-1 for 1 M H2SO4 and 6 M KOH and 120 F g-1 for 1 M NaCl. The capacitance was slightly reduced by 2.5% after cycling to 1.2 V with 1.28 A g-1 in 1 M NaCl for 10,000 times.

Effect of binders on 500mg metformin hydrochloride tablets produced by wet granulation

Directory of Open Access Journals (Sweden)

LUCIANA CATIA BLOCK

2009-12-01

Full Text Available Metformin hydrochloride (MH is an oral hypoglycemic agent and a high-dose drug that has poor flow and compression properties. In this study, the feasibility of developing adequate, low cost 500mg tablets of metformin hydrochloride by wet granulation was tested with several binders (Starch / PVP K30®; Starch 1500® /PVP K30®, PVP K30® and PVP K90® in a simple tablet press of the type used in small pharmaceutical laboratories. The drug powder was tested for ability to flow, by determining Carr’s Index (CI and the Hausner ratio (HR. Differential scanning calorimetry and thermogravimetric analysis were carried out on isolated MH and 1:1 (w/w binary mixtures with the excipients. The size distribution, friability, flow properties and drug content of the granules were analyzed, as were the hardness, friability, disintegration, dissolution and uniformity of the dosage form. The drug powder showed CI > 22% and HR > 1.25, characteristic of a poor flow powder, and no significant incompatibilities with the excipients. All the granules showed adequate flow properties and were suitable for pressing into tablets, all of which complied with pharmacopeial specifications. The starch /PVP K30® and starch 1500® /PVP K30® mixtures were best for producing 500 mg MH tablets. Keywords: Metformin hydrochloride. Tablets. Wet granulation. Binders.

Smooth-surface silver nanowire electrode with high conductivity and transparency on functional layer coated flexible film

Energy Technology Data Exchange (ETDEWEB)

Lee, So Hee; Lim, Sooman; Kim, Haekyoung, E-mail: hkkim@ynu.ac.kr

2015-08-31

Transparent conductive electrode (TCE) with silver nanowires has been widely studied as an alternative of indium tin oxide for flexible electronic or optical devices such as organic light-emitting diodes, and solar cells. However, it has an issue of surface roughness due to nanowire's intrinsic properties. Here, to achieve a smooth electrode with high conductivity and transmittance on polyethylene terephthalate (PET) substrates, a functional layer of poly(N-vinylpyrrolidone) (PVP) is utilized with a mechanical transfer process. The silver nanowire electrode on PVP-coated PET with low surface roughness of 9 nm exhibits the low sheet resistance of 18 Ω □{sup −1} and high transmittance of 87.6%. It is produced by transferring the silver nanowire electrode spin-coated on the glass to PVP-coated PET using a pressure of 10 MPa for 10 min. Silver nanowire electrode on PVP-coated PET demonstrates the stable sheet resistance of 18 Ω □{sup −1} after the mechanical taping test due to strong adhesion between PVP functional layer and silver nanowires. Smooth TCE with silver nanowires could be proposed as a transparent electrode for flexible electronic or optical devices, which consist of thin electrical active layers on TCE. - Highlights: • Silver nanowire (Ag NWs) transparent electrodes were fabricated on flexible film. • Flexible film was coated with poly N-vinylpyrrolidone (PVP). • PVP layer plays roles as an adhesive layer and matrix in electrode. • Ag NWs electrode exhibited with low surface roughness of 9 nm. • Ag NWs electrode has a low resistance (18 Ω ☐{sup −1}) and high transmittance (87.6%)

Smooth-surface silver nanowire electrode with high conductivity and transparency on functional layer coated flexible film

International Nuclear Information System (INIS)

Lee, So Hee; Lim, Sooman; Kim, Haekyoung

2015-01-01

Transparent conductive electrode (TCE) with silver nanowires has been widely studied as an alternative of indium tin oxide for flexible electronic or optical devices such as organic light-emitting diodes, and solar cells. However, it has an issue of surface roughness due to nanowire's intrinsic properties. Here, to achieve a smooth electrode with high conductivity and transmittance on polyethylene terephthalate (PET) substrates, a functional layer of poly(N-vinylpyrrolidone) (PVP) is utilized with a mechanical transfer process. The silver nanowire electrode on PVP-coated PET with low surface roughness of 9 nm exhibits the low sheet resistance of 18 Ω □ −1 and high transmittance of 87.6%. It is produced by transferring the silver nanowire electrode spin-coated on the glass to PVP-coated PET using a pressure of 10 MPa for 10 min. Silver nanowire electrode on PVP-coated PET demonstrates the stable sheet resistance of 18 Ω □ −1 after the mechanical taping test due to strong adhesion between PVP functional layer and silver nanowires. Smooth TCE with silver nanowires could be proposed as a transparent electrode for flexible electronic or optical devices, which consist of thin electrical active layers on TCE. - Highlights: • Silver nanowire (Ag NWs) transparent electrodes were fabricated on flexible film. • Flexible film was coated with poly N-vinylpyrrolidone (PVP). • PVP layer plays roles as an adhesive layer and matrix in electrode. • Ag NWs electrode exhibited with low surface roughness of 9 nm. • Ag NWs electrode has a low resistance (18 Ω ☐ −1 ) and high transmittance (87.6%)

Novel ultra-cryo milling and co-grinding technique in liquid nitrogen to produce dissolution-enhanced nanoparticles for poorly water-soluble drugs.

Science.gov (United States)

Sugimoto, Shohei; Niwa, Toshiyuki; Nakanishi, Yasuo; Danjo, Kazumi

2012-01-01

A novel ultra-cryo milling micronization technique for pharmaceutical powders using liquid nitrogen (LN2 milling) was used to grind phenytoin, a poorly water-soluble drug, to improve its dissolution rate. LN2 milling produced particles that were much finer and more uniform in size and shape than particles produced by jet milling. However, the dissolution rate of LN2-milled phenytoin was the same as that of unground phenytoin due to agglomeration of the submicron particles. To overcome this, phenytoin was co-ground with polyvinylpyrrolidone (PVP). The dissolution rate of co-ground phenytoin was much higher than that of original phenytoin, single-ground phenytoin, a physical mixture of phenytoin and PVP, or jet-milled phenytoin. X-Ray diffraction showed that the crystalline state of mixtures co-ground by LN2 milling remained unchanged. The equivalent improvement in dissolution, whether phenytoin was co-ground or separately ground and then mixed with PVP, suggested that even when co-ground, the grinding of PVP and phenytoin occurs essentially independently. Mixing original PVP with ground phenytoin provided a slight improvement in dissolution, indicating that the particle size of PVP is important for improving dissolution. When mixed with ground phenytoin, PVP ground by LN2 milling aided the wettability and dispersion of phenytoin, enhancing utilization of the large surface area of ground phenytoin. Co-grinding phenytoin with other excipients such as Eudragit L100, hypromellose, hypromellose acetate-succinate, microcrystalline cellulose, hydroxypropylcellulose and carboxymethyl cellulose also improved the dissolution profile, indicating an ultra-cryo milling and co-grinding technique in liquid nitrogen has a broad applicability of the dissolution enhancement of phenytoin.

Photochemical synthesis of copper nanoparticles incorporated in poly(vinyl pyrrolidone)

International Nuclear Information System (INIS)

Giuffrida, Salvatore; Costanzo, Lucia L.; Ventimiglia, Giorgio; Bongiorno, Corrado

2008-01-01

The effect of the presence of poly(vinyl pyrrolidone) (PVP) on the copper nanoparticle formation, obtained by UV irradiation of ethanol solution of Cu(acac) 2 (acac = 2,4-pentanedionato), was investigated. At 254 nm, in conditions of light completely absorbed by complex, the PVP exhibited protective and stabilizing effects, as shown by the formation of a colloidal copper solution and by a block of the heterogeneous process, which leads to thin film formation on the quartz walls. The colloidal solution was tested for several months by plasmon position and it was found that it remained unaltered in inert atmosphere, but returned to the starting complex on contact with air. The PVP ability to control the particle size was investigated by carrying out photoreduction sensitized by Hacac at 254 and 300 nm, in the presence of PVP concentration varying from 0 to 0.2 M. In this range it was possible to obtain copper nanoparticles of dimensions decreasing from 30 to 4 nm. Besides this, the PVP (0.005-0.05 M) role as sensitizer was investigated by irradiating solutions of Cu(acac) 2 at 300 nm which is an inactive wavelength for copper reduction by direct light absorption. It was found that the PVP was an efficient sensitizer of the copper photoreduction. The nanoparticles were characterized by plasmon band, Trasmission Electron Microscope (TEM) as well as Dynamic Light Scattering (DSL) analysis. The overall results evidence the advantages of the PVP use in the nanoparticle copper formation through the photochemical technique such as the exclusive formation of colloidal copper, their size control, stable colloidal solution and complete return to the starting complex.

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

International Nuclear Information System (INIS)

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

2015-01-01

We investigated effects of Ag_2S engineered nanomaterials (ENMs), polyvinylpyrrolidone (PVP) coated Ag ENMs (PVP-Ag), and Ag"+ on arbuscular mycorrhizal fungi (AMF), their colonization of tomato (Solanum lycopersicum), and overall microbial community structure in biosolids-amended soil. Concentration-dependent uptake was measured in all treatments. Plants exposed to 100 mg kg"−"1 PVP-Ag ENMs and 100 mg kg"−"1 Ag"+ exhibited reduced biomass and greatly reduced mycorrhizal colonization. Bacteria, actinomycetes and fungi were inhibited by all treatment classes, with the largest reductions measured in 100 mg kg"−"1 PVP-Ag ENMs and 100 mg kg"−"1 Ag"+. Overall, Ag_2S ENMs were less toxic to plants, less disruptive to plant-mycorrhizal symbiosis, and less inhibitory to the soil microbial community than PVP-Ag ENMs or Ag"+. However, significant effects were observed at 1 mg kg"−"1 Ag_2S ENMs, suggesting that the potential exists for microbial communities and the ecosystem services they provide to be disrupted by environmentally relevant concentrations of Ag_2S ENMs. - Highlights: • PVP-Ag and Ag"+ inhibited AMF colonization more readily than Ag_2S ENMs. • Impact of PVP-Ag ENMs and Ag"+ on microbial communities larger than for Ag_2S ENMs. • Significant changes in microbial communities in response to Ag_2S ENMs at 1 mg kg"−"1. - Although Ag_2S ENMs are less toxic to soil microorganisms than pristine nanomaterials or ions, some effects are observed on soil microbial communities at relevant concentrations.

Assessment of gold nanoparticle effects in a marine teleost (Sparus aurata) using molecular and biochemical biomarkers

Energy Technology Data Exchange (ETDEWEB)

Teles, M., E-mail: mteles0@gmail.com [Department of Cell Biology, Physiology and Immunology, Universitat Autònoma de Barcelona, 08193 Barcelona (Spain); Fierro-Castro, C. [Department of Cell Biology, Physiology and Immunology, Universitat Autònoma de Barcelona, 08193 Barcelona (Spain); Na-Phatthalung, P. [Department of Microbiology and Excellent Research Laboratory on Natural Products, Faculty of Science and Natural Product Research Center of Excellence, Prince of Songkla University, Hat Yai, Songkhla 90112 (Thailand); Tvarijonaviciute, A. [Department of Medicine and Animal Surgery, Universitat Autònoma de Barcelona, 08193 Barcelona (Spain); Trindade, T. [Department of Chemistry & CICECO, University of Aveiro, 3810-193 Aveiro (Portugal); Soares, A.M.V.M. [Department of Biology & CESAM, University of Aveiro, 3810-193 Aveiro (Portugal); Tort, L. [Department of Cell Biology, Physiology and Immunology, Universitat Autònoma de Barcelona, 08193 Barcelona (Spain); Oliveira, M. [Department of Biology & CESAM, University of Aveiro, 3810-193 Aveiro (Portugal)

2016-08-15

Highlights: • AuNP effects were investigated at molecular and biochemical levels in Sparus aurata. • AuNP coated with PVP exerts more effects than AuNP coated with citrate. • AuNP-PVP induced changes in antioxidant, immune and apoptosis related-genes mRNA levels. • The increase in plasma TOS indicates that AuNP-PVP generates oxidative stress. • AuNP-PVP induced in S. aurata a non-monotonic response pattern. - Abstract: Gold nanoparticles (AuNP) are increasingly employed in a variety of applications and are likely to be increasing in the environment, posing a potential emerging environmental threat. Information on possible hazardous effects of engineered nanoparticles is urgently required to ensure human and environmental safety and promote the safe use of novel nanotechnologies. Nevertheless, there is a lack of comprehensive knowledge on AuNP effects in marine species. The present study aimed to assess AuNP effects in a marine teleost, Sparus aurata, by combining endpoints at different biological levels (molecular and biochemical). For that purpose, fish were exposed via water for 96 h to 4, 80 and 1600 μg L{sup −1} of AuNP (∼40 nm) coated with citrate or polyvinylpyrrolidone (PVP). Results revealed a significant impact of AuNP-PVP in the hepatic expression of antioxidant, immune and apoptosis related genes. Total oxidative status was increased in plasma after exposure to the lowest concentration of AuNP-PVP, although without altering the total antioxidant capacity. Furthermore, AuNP did not induce significant damage in the liver since the activity of neither hepatic indicator (aspartate aminotransferase and alkaline phosphatase) increased. Overall, the present study demonstrated that AuNP, even with a biocompatible coating is able to alter oxidative status and expression of relevant target genes in marine fish. Another important finding is that effects are mainly induced by the lowest and intermediate concentrations of the PVP coated AuNP revealing

Avaliação da pressão venosa periférica na esclerose sistêmica Peripheral venous pressure in systemic sclerosis

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João Potério-Filho

2004-02-01

Full Text Available OBJETIVO: Estabelecer a utilidade da medida indireta da pressão venosa periférica (PVP na avaliação de pacientes com esclerose sistêmica (ES, comparando com uma população controle normal. MÉTODOS: Estudo prospectivo avaliando 18 pacientes esclerodérmicas do sexo feminino (sendo oito delas com úlcera cutânea isquêmica submetidas à medida indireta da PVP (por pletismografia. Os dados foram comparados a um grupo controle normal de 18 mulheres hígidas, pareadas para idade. RESULTADOS: Os níveis de pressão arterial foram semelhantes nos dois grupos. Os valores de PVP estavam significativamente diminuídos nos pacientes com ES (58.9 ± 11.6 mmHg no grupo ES e 96.9 ± 7.1 mmHg no grupo controle; p OBJECTIVE: The aim of this prospective study was to establish the usefulness of indirect measurement of peripheral venous pressure (PVP in the evaluation of patients with systemic sclerosis (SSc, comparing them with a normal control population. METHODS: Eighteen female SSc patients (eight patients presenting cutaneous ischemic ulcers were submitted to indirect measurement of the PVP (by plethysmography, and data were compared with a control group of 18 healthy women, paired by age. RESULTS: Arterial pressure levels were similar in both groups. PVP levels were significantly decreased in the SSc patients (58.9 ± 11.6 mmHg in the SSc group and 96.9 ± 7.1 mmHg in the control group; p < 0.0001; in the SSc group, patients with ischemic ulcers presented PVP levels significantly decreased compared with those patients without ulcers (50.6 ± 10.8 mmHg in the ulcer group and 65.5 ± 7.2 mmHg in the group without ulcers; p = 0.006. CONCLUSIONS: It can be concluded that decreased PVP in SSc is associated with a decrease in the blood flow of these patients, predisposing them to cutaneous ischemic ulcers.

Assessment of gold nanoparticle effects in a marine teleost (Sparus aurata) using molecular and biochemical biomarkers

International Nuclear Information System (INIS)

Teles, M.; Fierro-Castro, C.; Na-Phatthalung, P.; Tvarijonaviciute, A.; Trindade, T.; Soares, A.M.V.M.; Tort, L.; Oliveira, M.

2016-01-01

Highlights: • AuNP effects were investigated at molecular and biochemical levels in Sparus aurata. • AuNP coated with PVP exerts more effects than AuNP coated with citrate. • AuNP-PVP induced changes in antioxidant, immune and apoptosis related-genes mRNA levels. • The increase in plasma TOS indicates that AuNP-PVP generates oxidative stress. • AuNP-PVP induced in S. aurata a non-monotonic response pattern. - Abstract: Gold nanoparticles (AuNP) are increasingly employed in a variety of applications and are likely to be increasing in the environment, posing a potential emerging environmental threat. Information on possible hazardous effects of engineered nanoparticles is urgently required to ensure human and environmental safety and promote the safe use of novel nanotechnologies. Nevertheless, there is a lack of comprehensive knowledge on AuNP effects in marine species. The present study aimed to assess AuNP effects in a marine teleost, Sparus aurata, by combining endpoints at different biological levels (molecular and biochemical). For that purpose, fish were exposed via water for 96 h to 4, 80 and 1600 μg L"−"1 of AuNP (∼40 nm) coated with citrate or polyvinylpyrrolidone (PVP). Results revealed a significant impact of AuNP-PVP in the hepatic expression of antioxidant, immune and apoptosis related genes. Total oxidative status was increased in plasma after exposure to the lowest concentration of AuNP-PVP, although without altering the total antioxidant capacity. Furthermore, AuNP did not induce significant damage in the liver since the activity of neither hepatic indicator (aspartate aminotransferase and alkaline phosphatase) increased. Overall, the present study demonstrated that AuNP, even with a biocompatible coating is able to alter oxidative status and expression of relevant target genes in marine fish. Another important finding is that effects are mainly induced by the lowest and intermediate concentrations of the PVP coated AuNP revealing the

Preliminary Study on the Removal of Steroidal Estrogens Using TiO2-Doped PVDF Ultrafiltration Membranes

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Mingquan Wang

2016-04-01

Full Text Available Steroidal estrogens are a representative type of endocrine-disrupting chemical contaminant that has been detected in surface water. In this paper, modified polyvinylidene fluoride (PVDF membranes were prepared by adding different amounts of polyvinyl pyrrolidone (PVP and nano-TiO2 particles. PVDF-PVP membrane adsorption, UV photolysis and PVDF-PVP-TiO2 membrane photocatalysis performance were investigated by considering the rejection of estrone (E1 and 17β-estradiol (E2 in the cross-flow filtration experiments. The mechanism of photocatalytic degradation on TiO2-doped PVDF membranes was also evaluated. The results from the study indicated that adding PVP and nano-TiO2 appropriately in PVDF membranes could be an effective method for better E1and E2 rejection due to adsorption and photocatalytic degradation.

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

Science.gov (United States)

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.

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

Directory of Open Access Journals (Sweden)

Raghunath B. Shivappa

2017-09-01

Full Text Available 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.

Bulletin of Materials Science | Indian Academy of Sciences

Indian Academy of Sciences (India)

2) nanofibres are reported. These nanofibres were synthesized through electrospinning of polyvinyl pyrrolidone (PVP) / titanium tetra isopropoxide. Calcination of the obtained amorphous PVP/TiO2 nanofibres resulted in nanofibres of TiO2 ...

Investigation of Complexation of Linear Poly(N-vinyl-2-pyrrolidone) with Poly(methacrylic acid-co-methyl methacrylate) Gel

OpenAIRE

Liu, Guoqin; Yan, Guojin; Zou, Wenjun; Li, Zhengxin

2011-01-01

The contraction of poly(methacrylic acid-co-methyl methacrylate) (P(MAA-co-MMA)) gel induced by complexation with linear poly(N-vinyl-2-pyrrolidone) (PVP) is quite different from that of poly(acrylic acid) (PAA) or poly(methacrylic acid) (PMAA) gel. It was found that the concentration of PVP has a strong effect on the complexation with P(MAA-co-MMA) gel. When PVP was introduced into the P(MAA-co-MMA) network, its dynamic mechanic properties vary greatly between complexed and uncomplexed netwo...

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

Science.gov (United States)

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

2006-03-09

The molecular distribution in fully amorphous solid dispersions consisting of poly(vinylpyrrolidone) (PVP)-diazepam and inulin-diazepam was studied. One glass transition temperature (T(g)), as determined by temperature modulated differential scanning calorimetry (TMDSC), was observed in PVP-diazepam solid dispersions prepared by fusion for all drug loads tested (10-80 wt.%). The T(g) of these solid dispersions gradually changed with composition and decreased from 177 degrees C for pure PVP to 46 degrees C for diazepam. These observations indicate that diazepam was dispersed in PVP on a molecular level. However, in PVP-diazepam solid dispersions prepared by freeze drying, two T(g)'s were observed for drug loads above 35 wt.% indicating phase separation. One T(g) indicated the presence of amorphous diazepam clusters, the other T(g) was attributed to a PVP-rich phase in which diazepam was dispersed on a molecular level. With both the value of the latter T(g) and the DeltaC(p) of the diazepam glass transition the concentrations of molecular dispersed diazepam could be calculated (27-35 wt.%). Both methods gave similar results. Water vapour sorption (DVS) experiments revealed that the PVP-matrix was hydrophobised by the incorporated diazepam. TMDSC and DVS results were used to estimate the size of diazepam clusters in freeze dried PVP-diazepam solid dispersions, which appeared to be in the nano-meter range. The inulin-diazepam solid dispersions prepared by spray freeze drying showed one T(g) for drug loads up to 35 wt.% indicating homogeneous distribution on a molecular level. However, this T(g) was independent of the drug load, which is unexpected because diazepam has a lower T(g) than inulin (46 and 155 degrees C, respectively). For higher drug loads, a T(g) of diazepam as well as a T(g) of the inulin-rich phase was observed, indicating the formation of amorphous diazepam clusters. From the DeltaC(p) of the diazepam glass transition the amount of molecularly dispersed

Preparation and evaluation of famotidine polymorphs.

Science.gov (United States)

Nagaraju, Ravouru; Prathusha, Ande Penchala; Subhash Chandra Bose, Penjury; Kaza, Rajesh; Bharathi, Koganti

2010-06-01

The main objective of this study was to compare the behaviour of drug release among the famotidine polymorphs prepared by using various additives and solvents, by solvent evaporation method. The famotidine polyvinyl pyrrolidone polymorphs with different concentrations (0.5, 1 and 1.5%) were prepared by using solvent evaporation method. In these polymorphs of different concentrations 1% w/v polymorphs showed better release. Similarly, famotidine polymorphs of Tween 80 with different concentrations, polyethylene glycol 1% w/v and methanol was prepared. Famotidine polymorphs prepared the PVP (1% w/v) showed better drug release and solubility. DSC, FTIR, SEM and XRD studies were carried out. DSC studies revealed that PVP polymorphs were found to stable compared to other polymorphs. FTIR studies of the polymorphs prepared indicated that there was an interaction found in all polymorphs except PVP polymorphs indicating the absence of drug-additive interaction. SEM studies of PVP and methanol polymorphs revealed that they are tabular and prismatic and columnar respectively. These changes in morphology were due to variations in face dimensions and also properties of additives and solvent used in the preparation. XRD studies revealed that there is an increase in crystallinity in methanol polymorphs when compared to PVP polymorphs and pure drug. The mechanism of drug release was determined using zero order, first order and Hixon-Crowel equations. From the drug release kinetics these polymorphs followed first order and Hixon-Crowel release kinetics, exhibited fair linearity in their dissolution data. Further, in vivo studies were carried out for the evaluation of antiulcer activity. Based upon the drug release pattern and its kinetics only two of the prepared polymorphs of famotidine i.e. famotidine PVP polymorphs and famotidine methanol polymorphs were selected for animal studies. Antiulcer studies were carried out using pylorus ligation model and estimation of antioxidant

Cryopreservation of Indian red jungle fowl (Gallus gallus murghi) semen with polyvinylpyrrolidone.

Science.gov (United States)

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.

Does water chemistry affect the dietary uptake and toxicity of silver nanoparticles by the freshwater snail Lymnaea stagnalis?

International Nuclear Information System (INIS)

Oliver, Ana López-Serrano; Croteau, Marie-Noële; Stoiber, Tasha L.; Tejamaya, Mila; Römer, Isabella; Lead, Jamie R.; Luoma, Samuel N.

2014-01-01

Silver nanoparticles (AgNPs) are widely used in many applications and likely released into the aquatic environment. There is increasing evidence that Ag is efficiently delivered to aquatic organisms from AgNPs after aqueous and dietary exposures. Accumulation of AgNPs through the diet can damage digestion and adversely affect growth. It is well recognized that aspects of water quality, such as hardness, affect the bioavailability and toxicity of waterborne Ag. However, the influence of water chemistry on the bioavailability and toxicity of dietborne AgNPs to aquatic invertebrates is largely unknown. Here we characterize for the first time the effects of water hardness and humic acids on the bioaccumulation and toxicity of AgNPs coated with polyvinyl pyrrolidone (PVP) to the freshwater snail Lymnaea stagnalis after dietary exposures. Our results indicate that bioaccumulation and toxicity of Ag from PVP-AgNPs ingested with food are not affected by water hardness and by humic acids, although both could affect interactions with the biological membrane and trigger nanoparticle transformations. Snails efficiently assimilated Ag from the PVP-AgNPs mixed with diatoms (Ag assimilation efficiencies ranged from 82 to 93%). Rate constants of Ag uptake from food were similar across the entire range of water hardness and humic acid concentrations. These results suggest that correcting regulations for water quality could be irrelevant and ineffective where dietary exposure is important. - Highlights: • AgNP coated with polyvinyl pyrrolidone (PVP), PVP-AgNP were efficiently assimilated by Lymnaea stagnalis. • Water chemistry has no influence on the dietary uptake of PVP-AgNP by snails. - L. Stagnalis assimilated PVP-AgNPs efficiently from food and water chemistry had no influence on their uptake and toxicity

Safety and feasibility of percutaneous vertebroplasty with radioactive {sup 153}Sm PMMA in an animal model

Energy Technology Data Exchange (ETDEWEB)

Lu Jun [Department of Radiotherapy, Xijing Hospital, Fourth Military Medical University, 15 West Changle Road, Xi' an 710032, Shaanxi Province (China); Deng Jinglan, E-mail: dengjinglan@gmail.com [Department of Nuclear Medicine, Xijing Hospital, Fourth Military Medical University, 15 West Changle Road, Xi' an 710032, Shaanxi Province (China); Zhao Haitao [Department of Radiology, Xijing Hospital, Fourth Military Medical University, 15 West Changle Road, Xi' an 710032, Shaanxi Province (China); Shi Mei [Department of Radiotherapy, Xijing Hospital, Fourth Military Medical University, 15 West Changle Road, Xi' an 710032, Shaanxi Province (China); Wang Jing [Department of Nuclear Medicine, Xijing Hospital, Fourth Military Medical University, 15 West Changle Road, Xi' an 710032, Shaanxi Province (China); Zhao Lina [Department of Radiotherapy, Xijing Hospital, Fourth Military Medical University, 15 West Changle Road, Xi' an 710032, Shaanxi Province (China)

2011-05-15

Purpose: We investigated the safety and feasibility of the combination of samarium-153-ethylenediamine tetramethylene phosphonate ({sup 153}Sm-EDTMP)-incorporated bone cement (BC) with percutaneous vertebroplasty (PVP) in dogs. Methods and materials: {sup 153}Sm-EDTMP-incorporated BC was prepared by combining solid {sup 153}Sm-EDTMP and polymethylmethacrylate (PMMA) immediately before PVP. It was then injected into the vertebrae of four healthy mongrel dogs (two males and two females) by PVP under CT guidance. Each dog was subjected to five PVP sessions at a {sup 153}Sm-EDTMP dose of 30-70 mCi. The suppressive effect of local injection of {sup 153}Sm-EDTMP on the hematopoietic system was evaluated through counting of peripheral blood cells. Distribution of {sup 153}Sm-EDTMP-incorporated BC and the status of tissues adjacent to injected vertebrae were evaluated with SPECT, CT and MRI. Histopathology was carried out to assess the influence of PVP on the vertebra and adjacent tissues at the microscopic level. Results: PVP was done successfully, and all dogs exhibited normal behavior and stable physical signs after procedures. {sup 153}Sm-EDTMP-incorporated BC was concentrated mainly in target vertebrae, and the peripheral blood cells remained within normal range. The spinal cord and tissues around BC did not exhibit signs of injury even when the dosage of {sup 153}Sm-EDTMP increased from 30 mCi to 70 mCi. Conclusion: A dose lower than 70 mCi of {sup 153}Sm is safe when it was injected into vertebrae. {sup 153}Sm-EDTMP-incorporated BC did not influence the effect of PVP. This means might strengthen anti-tumor activity locally for vertebra with osseous metastasis without damaging adjacent tissues.

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

Energy Technology Data Exchange (ETDEWEB)

Wang, Jingxia; Chen, Hao; Chen, Zhuping; Chen, Yuheng; Guo, Dan; Ni, Maojun; Liu, Siyang; Peng, Chaorong, E-mail: pengchaorong_siae@163.com

2016-06-01

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

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

Science.gov (United States)

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

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

Directory of Open Access Journals (Sweden)

Ching-Lin Fan

2017-07-01

Full Text Available 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.

Increased electrochemical properties of ruthenium oxide and graphene/ruthenium oxide hybrid dispersed by polyvinylpyrrolidone

International Nuclear Information System (INIS)

Chen, Yao; Zhang, Xiong; Zhang, Dacheng; Ma, Yanwei

2012-01-01

Highlights: ► A good dispersion of RuO 2 and graphene/RuO 2 is obtained by polyvinylpyrrolidone. ► PVP as a dispersant also can prevent the formation of metal Ru in graphene/RuO 2 . ► The max capacitances of the hybrid and RuO 2 reach 435 and 597 F g −1 at 0.2 A g −1 . ► The hybrid shows the best rate capability of 39% at 50 A g −1 . - Abstract: Ruthenium oxide has been prepared by a sol–gel method. Polyvinylpyrrolidone (PVP) as an excellent polymeric dispersant is adopted to prevent aggregation of ruthenium oxide. In order to enhance the rate capability of ruthenium oxide, graphene with residual oxygen functional groups as a 2D support has been merged into ruthenium oxide. These oxygen functional groups not only favor to form stable few layers of graphene colloids, but also offer the sites to anchor ruthenium oxide nanoparticles. X-ray diffraction infers that PVP can also hinder the partial formation of Ru by blocking the direct contact between the Ru 3+ and the graphene in the sol–gel synthesis of the hybrids. The ruthenium oxide and the graphene/ruthenium oxide hybrids dispersed by PVP have superior electrochemical properties due to good dispersing and protecting ability of PVP. Especially, the hybrids using PVP exhibit the best rate capability, indicating that the composites possess an advanced structure of combining sheets and particles in nano-scale.

A comparative study of high-viscosity cement percutaneous vertebroplasty vs. low-viscosity cement percutaneous kyphoplasty for treatment of osteoporotic vertebral compression fractures.

Science.gov (United States)

Sun, Kai; Liu, Yang; Peng, Hao; Tan, Jun-Feng; Zhang, Mi; Zheng, Xian-Nian; Chen, Fang-Zhou; Li, Ming-Hui

2016-06-01

The clinical effects of two different methods-high-viscosity cement percutaneous vertebroplasty (PVP) and low-viscosity cement percutaneous kyphoplasty (PKP) in the treatment of osteoporotic vertebral compression fractures (OVCFs) were investigated. From June 2010 to August 2013, 98 cases of OVCFs were included in our study. Forty-six patients underwent high-viscosity PVP and 52 patients underwent low-viscosity PKP. The occurrence of cement leakage was observed. Pain relief and functional activity were evaluated using the Visual Analog Scale (VAS) and Oswestry Disability Index (ODI), respectively. Restoration of the vertebral body height and angle of kyphosis were assessed by comparing preoperative and postoperative measurements of the anterior heights, middle heights and the kyphotic angle of the fractured vertebra. Nine out of the 54 vertebra bodies and 11 out of the 60 vertebra bodies were observed to have cement leakage in the high-viscosity PVP and low-viscosity PKP groups, respectively. The rate of cement leakage, correction of anterior vertebral height and kyphotic angles showed no significant differences between the two groups (P>0.05). Low-viscosity PKP had significant advantage in terms of the restoration of middle vertebral height as compared with the high-viscosity PVP (Pviscosity PVP and low-viscosity PKP have similar clinical effects in terms of the rate of cement leakage, restoration of the anterior vertebral body height, changes of kyphotic angles, functional activity, and pain relief. Low-viscosity PKP is better than high-viscosity PVP in restoring the height of the middle vertebra.

Biocompatibility index of antiseptic agents by parallel assessment of antimicrobial activity and cellular cytotoxicity.

Science.gov (United States)

Müller, Gerald; Kramer, Axel

2008-06-01

To assess the suitability of an antiseptic agent, both the microbicidal activity and the cytotoxic effect must be taken into consideration to derive biocompatible antibacterial agents. We defined the biocompatibility index (BI) by measuring the antibacterial activity against the test organisms Escherichia coli and Staphylococcus aureus and, in parallel, the cytotoxicity on cultured murine fibroblasts. The antiseptic agents tested were benzalkonium chloride (BAC), cetylpyridinium chloride (CPC), chlorhexidine digluconate (CHX), mild silver protein (MSP), octenidine dihydrochloride (OCT), polyhexamethylene biguanide (PHMB), povidone iodine in solution [PVP-I(s)], povidone iodine in ointment [PVP-I(o)], silver nitrate (AgNO(3)), silver (I) sulfadiazine (SSD) and triclosan (TRI). Assays were carried out for 30 min of exposure at 37 degrees C in the presence of cell culture medium containing 10% fetal bovine serum. The resulting dimensionless BI was defined as the ratio of the concentration at which 50% of the murine fibroblasts are damaged and the microbicidal effect producing at least 3 log(10) (99.9%) reduction. The resulting rank ordering of BI for the ratio of fibroblast cytotoxicity to E. coli toxicity was OCT > PHMB > CHX > PVP-I(o) > PVP-I(s) > BAC > CPC > TRI > MSP and that to S. aureus was OCT > PHMB > CHX > CPC > PVP-I(o) > BAC > PVP(s) > TRI > MSP. OCT and PHMB were the most suitable agents with a BI greater than 1. The BI presented may be a useful tool to evaluate antiseptic agents for use in clinical practice.

Radiation synthesis of size-controlled poly(N-vinyl pyrrolidone) nanogels and their use as antimicrobial agents

International Nuclear Information System (INIS)

Isik, S.D.; Gueven, O.

2011-01-01

Complete text of publication follows. Nanogels are swollen networks of hydrophilic polymers generally developed to carry drugs, proteins and biologically active substances for biomedical applications. They can be prepared by 1) physical assembling of interactive polymers, 2) polymerization of monomers in micro or nanoscale environment, 3) crosslinking of preformed polymers, 4) template-assisted nanofabrication of nanogel particles. Among these methods crosslinking of preformed polymer chains provide excellent applications, especially when ionizing radiation is used as the tool to induce crosslinking. Due to its low cytotoxicity, excellent biocompatibility and non-carcinogenic and non-allergic properties, poly(N-vinyl pyrrolidone) (PVP) has been widely used in biomedical applications, hence the main reason for its selection in this work for the synthesis of its nanogels. PVP nanogels were prepared by gamma irradiation of its dilute aqueous solutions up to 15 kGy. The coil sizes of PVP chains were initially controlled by using acetone/water mixture as the solvent and further irradiations fixed the sizes by intramolecular crosslinking. By changing the concentration of PVP solutions, solvent composition and dose it was possible to prepare nanogels within 40-230 nm sizes. The nanogels were characterized by dynamic light scattering, scanning electron microscopy and atomic force microscopy. GPC has also been used to follow the changes in the coil sizes and distributions upon irradiations. The PVP nanogels thus synthesized were complexed with iodine in aqueous KI-I 2 solutions. Nanogels comprised of typical PVP-iodine complexes were tested for their antiseptic properties.

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

International Nuclear Information System (INIS)

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

2016-01-01

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

Dispersing surface-modified imogolite nanotubes in polar and non-polar solvents

Science.gov (United States)

Li, Ming; Brant, Jonathan A.

2018-02-01

Furthering the development of nanocomposite structures, namely membranes for water treatment applications, requires that methods be developed to ensure nanoparticle dispersion in polar and non-polar solvents, as both are widely used in associated synthesis techniques. Here, we report on a two-step method to graft polyvinylpyrrolidone (PVP), and a one-step method for octadecylphosphonic acid (OPA), onto the outer surfaces of imogolite nanotubes. The goal of these approaches was to improve and maintain nanotube dispersion in polymer compatible polar and non-polar solvents. The PVP coating modified the imogolite surface charge from positive to weakly negative at pH ≤ 9; the OPA made it weakly positive at acidic pH values to negative at pH ≥ 7. The PVP surface coating stabilized the nanotubes through steric hindrance in polar protic, dipolar aprotic, and chloroform. In difference to the PVP, the OPA surface coating allowed the nanotubes to be dispersed in n-hexane and chloroform, but not in the polar solvents. The lack of miscibility in the polar solvents, as well as the better dispersion in n-hexane, was attributed to the stronger hydrophobicity of the OPA polymer relative to the PVP. [Figure not available: see fulltext.

Povidone-iodine: an anti-oedematous agent?

Science.gov (United States)

Arakeri, Gururaj; Brennan, Peter A

2011-02-01

Polyvinylpyrrolidone-iodine (PVP-I) is a well-known antiseptic, widely used in various preparations and concentrations in all surgical fields. It is also used as an irrigant for open wounds and in some centres for irrigating sockets after tooth extraction. One of the authors (GA) incidentally discovered an anti-oedematous effect of PVP-I after using it in low concentration as an irrigant/coolant during the surgical removal of lower third molars. A prospective randomized clinical trial was subsequently performed on 50 patients (25 control, 25 treatment group) undergoing removal of impacted lower third molars. In the treatment group a 0.5% PVP-I solution at a concentration of 0.5mg/ml (we call it as "Arakeri's iodine solution") resulted in a significant reduction in postoperative swelling compared with the control group (P<0.01). This effect of PVP-I was suspected due to its inhibitory effect on leukotriene B4 and leukocyte extravasation (chemotaxis). Further evaluation of the effects of PVP-I as an irrigant in oral and maxillofacial surgery is needed. Copyright © 2010 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.

Spray drying of spherical Li{sub 4}Ti{sub 5}O{sub 12}/C powders using polyvinyl pyrrolidone as binder and carbon source

Energy Technology Data Exchange (ETDEWEB)

Liu, Wei [Research Center for New Energy Technology, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050 (China); University of Chinese Academy of Sciences, Beijing 110049 (China); Shanghai Nanotechnology Promotion Center, Shanghai 200237 (China); Wang, Qian; Cao, Chunhui [Research Center for New Energy Technology, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050 (China); University of Chinese Academy of Sciences, Beijing 110049 (China); Han, Xuewu [Research Center for New Energy Technology, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050 (China); Zhang, Jian, E-mail: zjskycn@163.com [Research Center for New Energy Technology, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050 (China); Xie, Xiaohua, E-mail: xiaohuaxie@126.com [Research Center for New Energy Technology, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050 (China); Xia, Baojia [Research Center for New Energy Technology, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050 (China); University of Chinese Academy of Sciences, Beijing 110049 (China)

2015-02-05

Highlights: • The spherical Li{sub 4}Ti{sub 5}O{sub 12}/C granules were prepared by spray drying. • Polyvinyl pyrrolidone (PVP) was used as binder and carbon source. • Tap density and spherical structure increase with the increase of PVP content. • Li{sub 4}Ti{sub 5}O{sub 12}/C granules exhibits better rate capability and excellent cyclability. - Abstract: Polyvinyl pyrrolidone (PVP) was used as binder and carbon source to synthesize stable and spherical Li{sub 4}Ti{sub 5}O{sub 12}/C granules by spray drying. The effects of PVP content and atmospheres on the properties of Li{sub 4}Ti{sub 5}O{sub 12} were investigated. The obtained samples were characterized by X-ray diffraction, scanning electron microscopy, Raman spectroscopy, and electrochemical tests, respectively. The results indicate that the average particle size, tap density and degree of spherical structure increase accordingly to the increase of PVP content. However, the large secondary particle would deteriorate the rate capacity at high current density. The carbon coating could significantly improve the rate capacity, which is attributed to the smaller primary particle and higher electrical conductivity.

Poly(vinyl pyrrolidone)-Chitosan implant for endoscopic treatment of vesicoureteral reflux

International Nuclear Information System (INIS)

Relleve, Lorna S.; Abad, Lucille V.; Aranilla, Charito T.; Dela Rosa, A.M.; Bolong, David T.; Bisnar, Carlo C.

2008-01-01

Radiation-crosslinked poly(vinyl pyrrolidone) (PVP)-Chitosan was prepared as a potential injectable implant for endoscopic treatment of vesicoureteral reflux (VUR). The physical and histological properties of PVP-Chitosan implant in comparison with the commercial dextranomer/hyaluronic acid copolymer (Deflux) have been evaluated in vivo by subcutaneous and abdominal injection in rats over a period of 6 months. The PVP-Chitosan implant was easily injected through 26-gauge needle. Monthly gross examination of the implanted sites showed no significant decrease in volume of implant and no local inflammatory reaction. Histological findings indicated no evidence of migration to the distant organs after 6 months of implantation. Results of this study indicated that PVP-Chitosan implant has properties of a good tissue augmenting substance such as stability, biocompatibility and non-migration but long-term studies are needed to evaluate its therapeutic efficiency. (author)

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

DEFF Research Database (Denmark)

Pundhir, Sachin; Bagger, Frederik Otzen; Lauridsen, Felicia Kathrine Bratt

2016-01-01

Formation of nucleosome free region (NFR) accompanied by specific histone modifications at flanking nucleosomes is an important prerequisite for enhancer and promoter activity. Due to this process, active regulatory elements often exhibit a distinct shape of histone signal in the form of a peak......-valley-peak (PVP) pattern. However, different features of PVP patterns and their robustness in predicting active regulatory elements have never been systematically analyzed. Here, we present PARE, a novel computational method that systematically analyzes the H3K4me1 or H3K4me3 PVP patterns to predict NFRs. We show...... four ENCODE cell lines and four hematopoietic differentiation stages, we identified several enhancers whose regulatory activity is stage specific and correlates positively with the expression of proximal genes in a particular stage. In conclusion, our results demonstrate that PVP patterns delineate...

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

Science.gov (United States)

Klavž, Janez; Gorenjak, Maksimiljan; Marinšek, Martin

2016-08-01

We report on a case of intoxication with a mix of new psychoactive substances. A 38-year-old male was brought to the emergency department (ED) following the ingestion of an unknown drug in a suicide attempt. During the transport, he became progressively more somnolent and unresponsive to painful stimuli. Urine and stomach content were collected on admission to be screened for drugs of abuse and medicinal drugs. After admission, the patient's next of kin presented five small grip seal plastic bags containing different powders/crystals, and they were sent for analysis along with urine and stomach content to the toxicology laboratory. An easy and rapid sample preparation technique was applied for the extraction of urine and stomach content. Samples were extracted with liquid-liquid extraction (LLE) technique and analysed using gas chromatography-mass spectrometry (GC-MS). A small amount of powder material from the bags was diluted in methanol and injected directly into the GC-MS instrument. Obtained spectra (EI) were evaluated against SWGDRUG library. Five different designer drugs were identified in the powder material, including synthetic cannabinoids (AB-CHMINACA, AB-FUBINACA) and synthetic cathinones (alpha-PHP, alpha-PVP and 4-CMC). With the exception of 4-CMC, all of these substances were also detected in the stomach content along with the prescription drugs. This is the first time that a positive identification of these five drugs has been made by a clinical laboratory in Slovenia. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Moessbauer spectroscopic characterization of macromolecule-metallochlorophyll complexes

International Nuclear Information System (INIS)

Inoue, H.; Fukuda, K.; Nonomura, Y.; Fluck, E.

1993-01-01

The bis-adducts of iron chlorophylls with poly(4-vinylpyridine-costyrene) (PVP) have been prepared and characterized by 57 Fe Moessbauer spectroscopy. The Moessbauer parameters of the PVP-adducts of iron chlorophylls are typical of low-spin iron(II) complexes. The central iron(III) ion is spontaneously reduced upon the axial coordination of PVP to iron(III) chlorophylls. The general tendency in the spontaneous reduction of the iron(III) chlorophylls has been interpreted in terms of the σ-donor and π-acceptor power of the axial macromolecular ligand. (orig.)

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

Science.gov (United States)

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.

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

NARCIS (Netherlands)

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

2006-01-01

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

Toxicity, Bioaccumulation and Biotransformation of Silver Nanoparticles in Marine Organisms

Science.gov (United States)

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

[Laservaporization of the prostate: current status of the greenlight and diode laser].

Science.gov (United States)

Rieken, M; Bachmann, A; Gratzke, C

2013-03-01

In the last decade laser vaporization of the prostate has emerged as a safe and effective alternative to transurethral resection of the prostate (TURP). This was facilitated in particular by the introduction of photoselective vaporization of the prostate (PVP) with a 532 nm 80 W KTP laser in 2002. Prospective randomized trials comparing PVP and TURP with a maximum follow-up of 3 years mostly demonstrated comparable functional results. Cohort studies showed a safe application of PVP in patients under oral anticoagulation and with large prostates. Systems from various manufacturers with different maximum power output and wavelengths are now available for diode laser vaporization of the prostate. Prospective randomized trials comparing diode lasers and TURP are not yet available. In cohort studies and comparative studies PVP diode lasers are characterized by excellent hemostatic properties but functional results vary greatly with some studies reporting high reoperation rates.

Colloidal stabilization of cerium-gadolinium oxide (CGO) suspensions via rheology

DEFF Research Database (Denmark)

Marani, Debora; Sudireddy, Bhaskar Reddy; Bentzen, Janet Jonna

2015-01-01

colloidally stable state. The method was applied to explore the ability of four commercial dispersants (acidic affine, neutral, basic affine, and polyvinylpyrrolidone (PVP)) to disperse cerium-gadolinium oxide (CGO) in ethanol. Only the acidic affine and the PVP dispersants were found to efficiently disperse...

Journal of Genetics | Indian Academy of Sciences

Indian Academy of Sciences (India)

carboxylate synthetase (P5CS) is the rate-limiting enzyme in proline biosynthesis in plants. Plasmid DNA (pCHF3-PvP5CS1 and pCHF3-PvP5CS2) containing the selectable neomycin phosphotransferase gene for kanamycin resistance and ...

Percutaneous vertebroplasty and percutaneous balloon kyphoplasty for the treatment of osteoporotic vertebral fractures: a systematic review and cost-effectiveness analysis.

Science.gov (United States)

Stevenson, Matt; Gomersall, Tim; Lloyd Jones, Myfanwy; Rawdin, Andrew; Hernández, Monica; Dias, Sofia; Wilson, David; Rees, Angie

2014-03-01

Percutaneous vertebroplasty (PVP) is a minimally invasive surgical procedure in which bone cement is injected into a fractured vertebra. Percutaneous balloon kyphoplasty (BKP) is a variation of this approach, in which an inflatable balloon tamp is placed in the collapsed vertebra prior to cement injection. To systematically evaluate and appraise the clinical effectiveness and cost-effectiveness of PVP and percutaneous BKP in reducing pain and disability in people with osteoporotic vertebral compression fractures (VCFs) in England and Wales. A systematic review was carried out. Ten databases including MEDLINE and CINAHL were searched from inception to November 2011, and supplemented by hand-searching relevant articles and contact with an expert. Studies met the inclusion criteria if they were randomised controlled trials (RCTs) including people with painful osteoporotic VCFs with a group receiving PVP or BKP. In addition, lead authors of identified RCTs were contacted for unpublished data. Primary outcomes were health-related quality of life; back-specific functional status/mobility; pain/analgesic use; vertebral body height and angular deformity; incidence of new vertebral fractures and progression of treated fracture. A manufacturer provided academic-in-confidence observational data indicating that vertebral augmentation may be associated with a beneficial mortality effect, and that, potentially, BKP was more efficacious than PVP. These data were formally critiqued. A mathematical model was constructed to explore the cost-effectiveness of BKP, PVP and operative placebo with local anaesthesia (OPLA) compared with optimal pain management (OPM). Six scenario analyses were conducted that assessed combinations of assumptions on mortality (differential beneficial effects for BKP and PVP; equal beneficial effects for BKP and PVP; and no effect assumed) and derivation of utility data (either mapped from visual analogue scale pain score data produced by a network meta

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

Directory of Open Access Journals (Sweden)

Ching-Lin Fan

2016-03-01

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

Investigation of Complexation of Linear Poly(N-vinyl-2-pyrrolidone with Poly(methacrylic acid-co-methyl methacrylate Gel

Directory of Open Access Journals (Sweden)

Guoqin Liu

2011-01-01

Full Text Available The contraction of poly(methacrylic acid-co-methyl methacrylate (P(MAA-co-MMA gel induced by complexation with linear poly(N-vinyl-2-pyrrolidone (PVP is quite different from that of poly(acrylic acid (PAA or poly(methacrylic acid (PMAA gel. It was found that the concentration of PVP has a strong effect on the complexation with P(MAA-co-MMA gel. When PVP was introduced into the P(MAA-co-MMA network, its dynamic mechanic properties vary greatly between complexed and uncomplexed networks. It had the following results: (1 the higher modulus ratio; (2 a slight contraction of gel.

Preparation and performance of novel polyvinylpyrrolidone/polyethylene glycol phase change materials composite fibers by centrifugal spinning

Science.gov (United States)

Zhang, Xiaoguang; Qiao, Jiaxin; Zhao, Hang; Huang, Zhaohui; Liu, Yangai; Fang, Minghao; Wu, Xiaowen; Min, Xin

2018-01-01

Currently, phase change materials (PCMs) composite fibers are typically prepared by electrospinning. However, electrospinning exhibits safety concerns and a low production rate, which limit its practical applications as a cost-effective fiber fabrication approach. Therefore, a novel, and simple centrifugal spinning technology is employed to extrude fibers from composite solutions using a high-speed rotary and perforated spinneret. The composite fibers based on polyvinylpyrrolidone (PVP) and polyethylene glycol (PEG) were prepared by centrifugal spinning. The SEM of PVP/PEG composite fibers indicated that the fibrous morphology is well preserved. The DSC and TGA indicated that PVP/PEG composite fibers exhibit good thermal properties.

Polyvinylpyrrolidone/Multiwall Carbon Nanotube Composite Based 36 deg. YX LiTaO3 Surface Acoustic Wave For Hydrogen Gas Sensing Applications

International Nuclear Information System (INIS)

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

2011-01-01

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

Quantitative analysis of povidone-iodine thin films by X-ray photoelectron spectroscopy and their physicochemical properties

Directory of Open Access Journals (Sweden)

Sa Anongtip

2017-06-01

Full Text Available In this study, povidone-iodine (PVP-I has been formulated as a topical spray to produce a thin film for the controlled release of I2. By means of experimental design, 27 formulations containing glycerol, ethanol, PEG 400, copovidone and HFA 134a as a propellant were prepared. The pH values of all formulations were in the range of 6-7. The viscosity was within the range of 11.9-85.9 mPa s. The surface tensions were 20.3 to 24.6 mN m-1 and the contact angles were between 19.3 and 38.7°. The assays for the iodine contents were within acceptable range (80-120 %. X-ray photoelectron spectroscopy analysis revealed the ionized form of iodine was much higher than the unionized form. The MIC and MBC values of the PVP-I sprays against Staphylococcus aureus, S. epidermidis and Pseudomonas aeruginosa were higher than that of commercial PVP-I solution. The cytotoxicity study confirmed that the PVP-I spray had lower toxic effects on keratinocytes and fibroblasts compared to the commercial PVP-I solution. The formulation containing 59 % ethanol, 18 % copovidone and 12 % PEG 400 showed good antibacterial activity.

Relationship between personality disorder functioning styles and the emotional states in bipolar I and II disorders.

Directory of Open Access Journals (Sweden)

Jiashu Yao

Full Text Available Bipolar disorder types I (BD I and II (BD II behave differently in clinical manifestations, normal personality traits, responses to pharmacotherapies, biochemical backgrounds and neuroimaging activations. How the varied emotional states of BD I and II are related to the comorbid personality disorders remains to be settled.We therefore administered the Plutchick - van Praag Depression Inventory (PVP, the Mood Disorder Questionnaire (MDQ, the Hypomanic Checklist-32 (HCL-32, and the Parker Personality Measure (PERM in 37 patients with BD I, 34 BD II, and in 76 healthy volunteers.Compared to the healthy volunteers, patients with BD I and II scored higher on some PERM styles, PVP, MDQ and HCL-32 scales. In BD I, the PERM Borderline style predicted the PVP scale; and Antisocial predicted HCL-32. In BD II, Borderline, Dependent, Paranoid (- and Schizoid (- predicted PVP; Borderline predicted MDQ; Passive-Aggressive and Schizoid (- predicted HCL-32. In controls, Borderline and Narcissistic (- predicted PVP; Borderline and Dependent (- predicted MDQ.Besides confirming the different predictability of the 11 functioning styles of personality disorder to BD I and II, we found that the prediction was more common in BD II, which might underlie its higher risk of suicide and poorer treatment outcome.

Study of cyanide removal from contaminated water using zinc peroxide nanomaterial.

Science.gov (United States)

Uppal, Himani; Tripathy, S Swarupa; Chawla, Sneha; Sharma, Bharti; Dalai, M K; Singh, S P; Singh, Sukhvir; Singh, Nahar

2017-05-01

The present study highlights the potential application of zinc peroxide (ZnO 2 ) nanomaterial as an efficient material for the decontamination of cyanide from contaminated water. A process patent for ZnO 2 synthesis has been granted in United States of America (US Patent number 8,715,612; May 2014), South Africa, Bangladesh, and India. The ZnO 2 nanomaterial was capped with polyvinylpyrrolidone (PVP) to control the particle size. The PVP capped ZnO 2 nanomaterial (PVP-ZnO 2 ) before and after adsorption of cyanide was characterized by scanning electron microscope, transmission electron microscope, X-ray diffractometer, Fourier transform infrared spectroscopy and time of flight-secondary ion mass spectrometry. The remaining concentration of cyanide after adsorption by PVP-ZnO 2 was determined using ion chromatograph. The adsorption of cyanide over PVP-ZnO 2 was also studied as a function of pH, adsorbent dose, time and concentration of cyanide. The maximum removal of cyanide was observed in pH range 5.8-7.8 within 15min. The adsorption data was fitted to Langmuir and Fruendlich isotherm and it has been observed that data follows both the isotherms and also follows second order kinetics. Copyright © 2016. Published by Elsevier B.V.

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

Energy Technology Data Exchange (ETDEWEB)

Bonan, Roberta F. [Departamento de Engenharia de Materiais (DEMAT), Universidade Federal da Paraíba (UFPB), Cidade Universitária, 58.051-900 João Pessoa, PB (Brazil); Centro de Ciências da Saúde (CCS), Universidade Federal da Paraíba (UFPB), Cidade Universitária, 58.051-900 João Pessoa, PB (Brazil); Bonan, Paulo R.F.; Batista, André U.D.; Sampaio, Fábio C.; Albuquerque, Allan J.R. [Centro de Ciências da Saúde (CCS), Universidade Federal da Paraíba (UFPB), Cidade Universitária, 58.051-900 João Pessoa, PB (Brazil); Moraes, Maria C.B. [Embrapa Recursos Genéticos e Biotecnologia, Parque Estação Ecológica, W/5 Norte (Final) Cenargen (Laboratório de Semioquímicos) ASA NORTE, 70770900 Brasília, DF (Brazil); Mattoso, Luiz H.C. [Laboratório Nacional de Nanotecnologia para o Agronegócio (LNNA), Embrapa Instrumentação Agropecuária (CNPDIA), Rua XV de Novembro, 1452, Centro, 13.560, 970 São Carlos, SP (Brazil); Glenn, Gregory M. [United States Department of Agriculture (USDA), Western Regional Research Center (WRRC), Bioproduct Chemistry and Engineering - BCE, Albany, CA 94710 (United States); and others

2015-03-01

In this study poly(lactic acid) (PLA) and polyvinylpyrrolidone (PVP) micro- and nanofiber mats loaded with Copaiba (Copaifera sp.) oil were produced by solution blow spinning (SBS). The Copaiba (Copaifera sp.) oil was characterized by gas chromatography (GC). Neat PLA and four PLA/PVP blends containing 20% (wt.%) oil were spun and characterized by scanning electron microscopy (SEM) and by studying the surface contact angle, in vitro release rate, and antimicrobial activity. All compositions evaluated were able to produce continuous and smooth fibers by SBS. The addition of PVP increased fiber diameter, and decreased the surface contact angle. GC analysis demonstrated that the main component of the Copaiba oil was β-caryophyllene, a known antimicrobial agent. In vitro release tests of Copaiba oil volatiles demonstrated a higher release rate in fibers containing PVP. Fiber mats made from blends containing higher amounts of PVP had greater antimicrobial action against Staphylococcus aureus. The results confirm the potential of the fiber mats for use in controlled drug release and could lead to promising applications in the biomedical field. - Highlights: • An efficient method for production of antimicrobial nanofiber mats using solution blow spinning was reported. • Nanofiber mats containing Copaiba oil were efficient against Staphylococcus aureus. • Nanofiber composition changed morphological properties and antimicrobial action.

Day care bipolar transurethral resection vs photoselective vaporisation under sedoanalgesia: A prospective, randomised study of the management of benign prostatic hyperplasia.

Science.gov (United States)

Sood, Rajeev; Manasa, T; Goel, Hemant; Singh, Ritesh Kumar; Singh, Rajpal; Khattar, Nikhil; Pandey, Praveen

2017-12-01

To conduct a prospective randomised study comparing the safety, effectiveness and treatment outcomes in patients undergoing bipolar transurethral resection of the prostate (bTURP) and photoselective vaporisation of the prostate (PVP) under sedoanalgesia, as sedoanalgesia is a safe and effective technique suitable for minimally invasive endourological procedures and although studies have confirmed that both TURP and PVP are feasible under sedoanalgesia there are none comparing the two. Between November 2014 and April 2016, all patients satisfying the eligibility criteria underwent either bTURP or PVP under sedoanalgesia after randomisation. The groups were compared for functional outcomes, visual analogue scale (VAS) pain scores (range 0-10), perioperative variables and complications, with a follow-up of 3 months. In all, 42 and 36 patients underwent bTURP and PVP under sedoanalgesia, respectively. The mean VAS pain score was operating time [mean (SD) 55.64 (12.8) vs 61.79 (14.2) min, P  = 0.035], shorter duration of hospitalisation [mean (SD) 14.58 (2.81) vs 19.21 (2.82) h, P  post-void residual urine volume at 3 months were similar in both groups. None of our patients required re-admission or re-operation. Both PVP and bTURP can be carried out safely under sedoanalgesia with excellent treatment outcomes.

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

Science.gov (United States)

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

2015-01-01

Background Bipolar disorder types I (BD I) and II (BD II) behave differently in clinical manifestations, normal personality traits, responses to pharmacotherapies, biochemical backgrounds and neuroimaging activations. How the varied emotional states of BD I and II are related to the comorbid personality disorders remains to be settled. Methods We therefore administered the Plutchick – van Praag Depression Inventory (PVP), the Mood Disorder Questionnaire (MDQ), the Hypomanic Checklist-32 (HCL-32), and the Parker Personality Measure (PERM) in 37 patients with BD I, 34 BD II, and in 76 healthy volunteers. Results Compared to the healthy volunteers, patients with BD I and II scored higher on some PERM styles, PVP, MDQ and HCL-32 scales. In BD I, the PERM Borderline style predicted the PVP scale; and Antisocial predicted HCL-32. In BD II, Borderline, Dependant, Paranoid (-) and Schizoid (-) predicted PVP; Borderline predicted MDQ; Passive-Aggressive and Schizoid (-) predicted HCL-32. In controls, Borderline and Narcissistic (-) predicted PVP; Borderline and Dependant (-) predicted MDQ. Conclusion Besides confirming the different predictability of the 11 functioning styles of personality disorder to BD I and II, we found that the prediction was more common in BD II, which might underlie its higher risk of suicide and poorer treatment outcome. PMID:25625553

Polyvinylpyrrolidone-based semi-interpenetrating polymer networks as highly selective and chemically stable membranes for all vanadium redox flow batteries

Science.gov (United States)

Zeng, L.; Zhao, T. S.; Wei, L.; Zeng, Y. K.; Zhang, Z. H.

2016-09-01

Vanadium redox flow batteries (VRFBs) with their high flexibility in configuration and operation, as well as long cycle life are competent for the requirement of future energy storage systems. Nevertheless, due to the application of perfluorinated membranes, VRFBs are plagued by not only the severe migration issue of vanadium ions, but also their high cost. Herein, we fabricate semi-interpenetrating polymer networks (SIPNs), consisting of cross-linked polyvinylpyrrolidone (PVP) and polysulfone (PSF), as alternative membranes for VRFBs. It is demonstrated that the PVP-based SIPNs exhibit extremely low vanadium permeabilities, which contribute to the well-established hydrophilic/hydrophobic microstructures and the Donnan exclusion effect. As a result, the coulombic efficiencies of VRFBs with PVP-based SIPNs reach almost 100% at 40 mA cm-2 to 100 mA cm-2; the energy efficiencies are more than 3% higher than those of VRFBs with Nafion 212. More importantly, the PVP-based SIPNs exhibit a superior chemical stability, as demonstrated both by an ex situ immersion test and continuously cycling test. Hence, all the characterizations and performance tests reported here suggest that PVP-based SIPNs are a promising alternative membrane for redox flow batteries to achieve superior cell performance and excellent cycling stability at the fraction of the cost of perfluorinated membranes.

Creating space for ‘informal’ seed systems in a plant variety protection system that is based on UPOV 1991

NARCIS (Netherlands)

Jonge, de B.; Munyi, P.

2017-01-01

Summary
Plant variety protection (PVP) gives a right holder
(breeder) the possibility to exclude others from using his
or her invention (plant variety) for a particular period.
African regional organizations are currently establishing
PVP systems that are in line with the

Semantic prioritization of novel causative genomic variants

KAUST Repository

Boudellioua, Imene

2017-04-17

Discriminating the causative disease variant(s) for individuals with inherited or de novo mutations presents one of the main challenges faced by the clinical genetics community today. Computational approaches for variant prioritization include machine learning methods utilizing a large number of features, including molecular information, interaction networks, or phenotypes. Here, we demonstrate the PhenomeNET Variant Predictor (PVP) system that exploits semantic technologies and automated reasoning over genotype-phenotype relations to filter and prioritize variants in whole exome and whole genome sequencing datasets. We demonstrate the performance of PVP in identifying causative variants on a large number of synthetic whole exome and whole genome sequences, covering a wide range of diseases and syndromes. In a retrospective study, we further illustrate the application of PVP for the interpretation of whole exome sequencing data in patients suffering from congenital hypothyroidism. We find that PVP accurately identifies causative variants in whole exome and whole genome sequencing datasets and provides a powerful resource for the discovery of causal variants.

Semantic prioritization of novel causative genomic variants

KAUST Repository

Boudellioua, Imene; Mohamad Razali, Rozaimi; Kulmanov, Maxat; Hashish, Yasmeen; Bajic, Vladimir B.; Goncalves-Serra, Eva; Schoenmakers, Nadia; Gkoutos, Georgios V.; Schofield, Paul N.; Hoehndorf, Robert

2017-01-01

Discriminating the causative disease variant(s) for individuals with inherited or de novo mutations presents one of the main challenges faced by the clinical genetics community today. Computational approaches for variant prioritization include machine learning methods utilizing a large number of features, including molecular information, interaction networks, or phenotypes. Here, we demonstrate the PhenomeNET Variant Predictor (PVP) system that exploits semantic technologies and automated reasoning over genotype-phenotype relations to filter and prioritize variants in whole exome and whole genome sequencing datasets. We demonstrate the performance of PVP in identifying causative variants on a large number of synthetic whole exome and whole genome sequences, covering a wide range of diseases and syndromes. In a retrospective study, we further illustrate the application of PVP for the interpretation of whole exome sequencing data in patients suffering from congenital hypothyroidism. We find that PVP accurately identifies causative variants in whole exome and whole genome sequencing datasets and provides a powerful resource for the discovery of causal variants.

Humidity Detection Using Metal Organic Framework Coated on QCM

KAUST Repository

Kosuru, Lakshmoji

2016-06-28

Quartz crystal microbalance (QCM) coated with poly-4-vinylpyridine (PVP) and metal organic framework HKUST-1 are investigated and compared for humidity sensing. Drop casting method is employed to coat the PVP and HKUST-1 solutions onto the surface of a quartz crystal microbalance. The resonance frequencies of these sensors with varying relative humidity (RH) from 22% RH to 69% RH are measured using impedance analysis method. The sensitivity, humidity hysteresis, response, and recovery times of these sensors are studied. The sensitivities of uncoated, PVP, and HKUST-1 coated QCM sensors are 7 Hz, 48 Hz, and 720 Hz, respectively, in the range of 22% RH–69% RH. The extraction of desorption rate and adsorption energy associated with the adsorption and desorption of water molecules on these surfaces reveals that HKUST-1 has better sensing properties than PVP and uncoated QCM sensors. In this work, the HKUST-1 coated QCM is shown to be a promising material for moisture detection.

Humidity Detection Using Metal Organic Framework Coated on QCM

Directory of Open Access Journals (Sweden)

Lakshmoji Kosuru

2016-01-01

Full Text Available Quartz crystal microbalance (QCM coated with poly-4-vinylpyridine (PVP and metal organic framework HKUST-1 are investigated and compared for humidity sensing. Drop casting method is employed to coat the PVP and HKUST-1 solutions onto the surface of a quartz crystal microbalance. The resonance frequencies of these sensors with varying relative humidity (RH from 22% RH to 69% RH are measured using impedance analysis method. The sensitivity, humidity hysteresis, response, and recovery times of these sensors are studied. The sensitivities of uncoated, PVP, and HKUST-1 coated QCM sensors are 7 Hz, 48 Hz, and 720 Hz, respectively, in the range of 22% RH–69% RH. The extraction of desorption rate and adsorption energy associated with the adsorption and desorption of water molecules on these surfaces reveals that HKUST-1 has better sensing properties than PVP and uncoated QCM sensors. In this work, the HKUST-1 coated QCM is shown to be a promising material for moisture detection.

Effect of Rehydration Fluid Osmolality on Plasma Volume and Vasopressin in Resting Dehydrated Men

Science.gov (United States)

Geelen, Ghislaine; Greenleaf, J. E.; Keil, L. C.; Wade, Charles E. (Technical Monitor)

1994-01-01

Elevated plasma vasopressin concentration [PVP], which may act as a dipsogen, decreases promptly following the ingestion of fluids in many mammals including humans. The purpose for this study was to determine whether fluids of varied electrolyte and carbohydrate composition and osmolality (Osm] would modify post-drinking decreases in [PVP] which could be attributed to interaction with plasma volume (PV)- or fluid-electrolyte interactive hormones. Five men (23-41 yr, 78.0 +/- SD 8.2 kg), water deprived for 24 h, drank six fluids (12 ml/kg, at 16.5C in 4.0-6.2 min): water (30 m0sm/kg), NaCl (70 mOsm/kg), NaCl + NaCitrate (270 mOsm/kg), NaCl + 9.7% glucose (650 mOsm/kg), and two commercial drinks containing various ionic and carbohydrate contents (380 and 390 mOsm/kg). Blood (20 ml/sample) was drawn at -5 min before and at +3, +9, +15, +30, and +70 min after drinking. Heart rate, blood pressures, and plasma renin activity, {Na+], [K+], [Osm], aldosterone, atrial natriuretic peptide, and epinephrine concentrations were unchanged after drinking. Post-drinking [PVP] decreased from 1.7 - 3.7 pg/ml within 3 min with all fluids independently of their composition, [Osm], or delta PV; with maximal depression to 0.1-0.7 pg/ml (p<0.05) by 15 min. The continued [PVP] depression with all fluids from 15 to 70 min was accompanied by unchanged plasma (Osm] but 1.8-7.6% increases (p<0.05) in PV with 3) fluids (2 commercial and NaCitrate) and no change with the others. Percent changes in mean [PVP] and plasma norepinephrine concentrations [PNE] at 15 min correlated -0.70 (P<0.10) suggesting that about half the variability in [PVP I I depression was associated with [PNE]. Thus, part of the mechanism for post-drinking [PVP] depression may involve a drinking stimulated norepinephrine (neural) factor.

Ion-Exchange-Induced Selective Etching for the Synthesis of Amino-Functionalized Hollow Mesoporous Silica for Elevated-High-Temperature Fuel Cells

DEFF Research Database (Denmark)

Zhang, Jin; Liu, Jian; Lu, Shanfu

2017-01-01

is verified through a successful synthesis of hollow mesoporous silica. After infiltration with phosphotungstic acid (PWA), PWA–NH2–HMS nanoparticles are dispersed in the poly(ether sulfone)–polyvinylpyrrolidone (PES–PVP) matrix, forming a hybrid PWA–NH2–HMS/PES–PVP nanocomposite membrane. The resultant...

Synthesis of iron nanoparticles with poly(1-vinylpyrrolidone-co-vinyl acetate) and its application to nitrate reduction

DEFF Research Database (Denmark)

Lee, Nara; Choi, Kyunghoon; Uthuppu, Basil

2014-01-01

This study aimed to synthesize dispersed and reactive nanoscale zero-valent iron (nZVI) with poly(1-vinylpyrrolidone-co-vinyl acetate) (PVP/VA), nontoxic and biodegradable stabilizer. The nZVI used for the experiments was prepared by reduction of ferric solution in the presence of PVP/VA with spe...

Stabilisation of amorphous furosemide increases the oral drug bioavailability in rats

DEFF Research Database (Denmark)

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

2015-01-01

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

Bulletin of Materials Science | Indian Academy of Sciences

Indian Academy of Sciences (India)

Hollow fibre microfiltration membranes were prepared by solution spinning process using polymer dope containing different amounts of polysulfone (PS), polyvinylpyrollidone (PVP) and ,-dimethylformamide (DMF). Spinning dope having PS: PVP: DMF (w/w) of 15: 5: 80, 15: 7: 78 and 17: 8: 75 were used for spinning to ...

Assessing the influence of risk factors on rates and dynamics of peripheral vein phlebitis: an observational cohort study.

Science.gov (United States)

Mestre Roca, Gabriel; Berbel Bertolo, Cristina; Tortajada Lopez, Purificación; Gallemi Samaranch, Gema; Aguilar Ramirez, Mari Carmen; Caylà Buqueras, Joan; Rodríguez-Baño, Jesús; Martinez, José Antonio

2012-07-21

To assess the influence of risk factors on the rates and kinetics of peripheral vein phlebitis (PVP) development and its theoretical influence in absolute PVP reduction after catheter replacement. All peripheral short intravenous catheters inserted during one month were included (1201 catheters and 967 patients). PVP risk factors were assessed by a Cox proportional hazard model. Cumulative probability, conditional failure of PVP and theoretical estimation of the benefit from replacement at different intervals were performed. Female gender, catheter insertion at the emergency or medical-surgical wards, forearm site, amoxicillin-clavulamate or aminoglycosides were independent predictors of PVP with hazard ratios (95 confidence interval) of 1.46 (1.09-2.15), 1.94 (1.01-3.73), 2.51 (1.29-4.88), 1.93 (1.20-3.01), 2.15 (1.45-3.20) and 2.10 (1.01-4.63), respectively. Maximum phlebitis incidence was reached sooner in patients with ≥2 risk factors (days 3-4) than in those with phlebitis/one catheter-day for devices with ≤1 risk factors to 0.26 for those with ≥3. The greatest benefit of routine catheter exchange was obtained by replacement every 60h. However, this benefit differed according to the number of risk factors: 24.8% reduction with ≥3, 13.1% with 2, and 9.2% with ≤1. PVP dynamics is highly influenced by identifiable risk factors which may be used to refine the strategy of catheter management. Routine replacement every 72h seems to be strictly necessary only in high-risk catheters. Copyright © 2011 Elsevier España, S.L. All rights reserved.

Costo Utilidad de Colágena Polivinil-Pirrolidona en el Tratamiento de Osteartrosis de Rodilla en México.

Science.gov (United States)

Burbano-Levy, Ximena; Qf, Diana Cardona; Act, Elsa Palacios; Alba, Israel Rico; Qf, León Zapata

2014-12-01

To assess the cost-utility of collagen-polyvinyl pyrrolidone (collagen-PVP), a new drug developed and manufactured in Mexico, compared to non-steroidal anti-inflammatory drugs in the treatment of patients with knee osteoarthritis (OA) in Mexico. A probabilistic Markov model with a lifetime horizon was designed to evaluate the costs and outcomes (QALYs) of collagen-PVP compared to NSAIDs in patients with OA. Data from randomized clinical trials conducted in México were obtained as input for probabilities. Utility values ​​were elicited from international publications and costs information and service utilization was obtained from official publications of the Instituto Mexicano de Seguro Social - IMSS. Cost per quality-adjusted life-years was calculated by using the Mexican Healthcare payer perspective. A discount rate of 5% for both cost and outcomes was used. Sensitivity analyzes were performed with variations in the parameters of gender, age, and price of collagen-PVP. Patients treated with collagen-PVP showed a gain of 6.62 QALYs compared with 5.36 in patients with NSAIDs. The cost-utility ratio was higher in the NSAID group (MEX$ 170,010.76/QALY) compared to collagen-PVP (MEX $ 130,953.63/QALY). The incremental cost-utility ratio was MEX $ 35,194.16. This is the first economic evaluation of a new medication developed in Mexico and conducted partially with local data. The results of this study allow concluding that collagen-PVP is deemed as the dominant alternative compared with NSAIDs in the treatment of knee osteoarthritis. Copyright © 2014 International Society for Pharmacoeconomics and Outcomes Research (ISPOR). Published by Elsevier Inc. All rights reserved.

Photovoltaic solar panel for a hybrid PV/thermal system

Energy Technology Data Exchange (ETDEWEB)

Zakharchenko, R.; Licea-Jimenez, L.; Perez-Garcia, S.A.; Perez-Robles, J.F.; Gonzalez-Hernandez, J.; Vorobiev, Y. [CINVESTAV-Queretaro, (Mexico); Vorobiev, P. [Universidad Autonoma de Queretaro, (Mexico). Facultad de Ingenieria; Dehesa-Carrasco, U. [Instituto Tec. Del Istmo, Oaxaco (Mexico). Dep. de Ingenieria Electromecanica

2004-05-01

The hybrid PV-thermal system was studied, with the photovoltaic panel (PVP) area much smaller than that of the solar collector. Performance of the different panels in the system was investigated, in particular, those made of crystalline (c-) Si, {alpha}-Si and CuInSe{sub 2} as well as different materials and constructions for the thermal contact between the panel and the collector. Our conclusion is that the PVP for application in a hybrid system needs a special design providing efficient heat extraction from it. PVP was designed and made. Its study has shown that this design provides the high electrical and thermal efficiency of the hybrid system. (author)

Direct crystallization of perovskite phase in PMN-PT thin films prepared by polyvinylpyrrolidone modified sol-gel processing and their properties

International Nuclear Information System (INIS)

Du, Z.H.; Zhang, T.S.; Zhu, M.M.; Ma, J.

2009-01-01

A modified sol-gel processing has been developed by using polyvinylpyrrolidone (PVP) as modifier and lead nitrate as lead source to synthesize (1-x)Pb(Mg 1/3 ,Nb 2/3 )O 3 -xPbTiO 3 (PMN-PT) thin films with x=0.23-0.43. With PVP additions, perovskite phase could directly crystallize from amorphous films at the temperature as low as 430 deg. C via bypassing the metastable phase-pyrochlore and crystallinity was significantly enhanced. The PVP addictives have been optimized with molecular weight 1/3 ,Nb 2/3 )O 3 -PbTiO 3 films via bypassing pyrochlore phase.

Shape-Selective Syntheses of Gold and Copper Nanostructures: Insights From Density-Functional Theory and Molecular Dynamics

Science.gov (United States)

Liu, Shih-Hsien

Density-functional theory (DFT) and molecular dynamics (MD) were used to resolve the origins of shape-selective syntheses of {111}-faceted Au nanostructures mediated by polyvinylpyrrolidone (PVP) as well as {100}-faceted Cu nanostructures mediated by hex- adecylamine(HDA) seen in experiment. For the work in PVP on Au surfaces, the hexagonal reconstruction of Au(100) was considered. DFT results indicate that the Au(111) surface covered by the PVP segment, 2-pyrrolidone (2P), has a lower surface energy than the 2P- covered (5 x 1) Au(100)-hex surface, and that PVP may exhibit a binding affinity for Au(111) comparable to or greater than (5 x 1) Au(100)-hex. With MD, it is shown that the PVP-covered Au(111) surface has a lower surface energy than the PVP-covered (5 x 1) Au(100)-hex surface, and that the atactic PVP isosamer chains have a binding affinity for Au(111) comparable to (5 x 1) Au(100)-hex. Also, the (5 x 1) Au(100)-hex surface may have a higher flux of Au atoms than the Au(111) surface. Therefore, the Au(111) surface would be thermodynamically and kinetically favored in PVP-mediated syntheses, leading to {111}-faceted Au nanostructures. For the work in HDA on Cu surfaces, DFT results show that the HDA-covered Cu(100) surface has a slightly higher surface energy than the HDA- covered Cu(111) surface. However, HDA has a significant binding preference on Cu(100) over Cu(111). Therefore, the Cu(100) surface would be kinetically favored in HDA-mediated syn- theses, leading to {100}-faceted Cu nanostructures. Further, a metal-organic many-body (MOMB) force field for HDA-Cu interactions was developed based on the DFT work, and the force field was used to resolve the HDA binding patterns on Cu(100) at molecular level. With MD, it is found that decylamine (DA) may be used as an effective capping agent in the synthesis of {100}-faceted Cu nanostructures since DA as well as HDA are organized on Cu surfaces and have the same binding preference on Cu(100) over Cu(111

Journal of Chemical Sciences | Indian Academy of Sciences

Indian Academy of Sciences (India)

Pt, Pd, Pt-Ag and Pd-Ag bimetallic nanoparticles were synthesized in ethylene glycol and glycerol using the microwave technique in the presence of a stabilizer poly(N-vinylpyrrolidone) (PVP). It has been observed that PVP is capable of complexing and stabilizing nanoparticles. Mixed clusters were formed by simultaneous ...

Polyvinylpyrrolidone as a New Fluorescent Sensor for Nitrate Ion

International Nuclear Information System (INIS)

Tang, I.H.; Lintang, H.O.; Leny Yuliati

2016-01-01

In this study, non-conjugated polyvinylpyrrolidone (PVP) was investigated for the first time as the potential polymeric material to sense nitrate ions by fluorescence spectroscopy. The PVP was diluted into various concentrations (3-10 %) and they were used to sense the nitrate ions in different concentrations (0.1-100 mM). The PVP showed two excitation peaks at 285 and 330 nm due to the presence of C=O and N-C groups, respectively. One strong emission at 400 or 408 nm was observed with the excitation at 285 or 330 nm. The higher value of quenching constant at excitation wavelength of 285 nm indicated that C=O site was more favored for NO 3 - ions sensing than the N-C site. The PVP 7 % gave the highest quenching constant; where the KSV value was 9.89 x 10 -3 mM -1 and 2.44 x 10 -3 mM -1 for excitation at 285 and 330 nm, respectively. The sensing capability was evaluated in the presence of interference ions (SO 4 2- , HCO 3 - , Cl - , and OH - ). It was observed that the interference ions interacted strongly with the C=O, but weakly with the N-C. Therefore, in the presence of the interference ions, the PVP would be a potential fluorescent sensor when it is excited at 330 nm. (author)

Polyvinylpyrrolidone-Capped Silver Nanoparticle Inhibits Infection of Carbapenem-Resistant Strain of Acinetobacter baumannii in the Human Pulmonary Epithelial Cell

Directory of Open Access Journals (Sweden)

Vishvanath Tiwari

2017-08-01

Full Text Available Acinetobacter baumannii, an opportunistic ESKAPE pathogen, causes respiratory and urinary tract infections. Its prevalence increases gradually in the clinical setup. Pathogenicity of Acinetobacter is significantly influenced by its ability to infect and survive in human pulmonary cells. Therefore, it is important to study the infection of A. baumannii in human pulmonary host cell (A-549, monitoring surface interacting and internalized bacteria. It was found that during infection of A. baumannii, about 40% bacteria adhered to A-549, whereas 20% got internalized inside pulmonary cell and induces threefold increase in the reactive oxygen species production. We have synthesized polyvinylpyrrolidone (PVP-capped AgNPs using chemical methods and tested its efficacy against carbapenem-resistant strain of A. baumannii. PVP-capped silver nanoparticles (PVP-AgNPs (30 µM have shown antibacterial activity against carbapenem-resistant strain of A. baumannii and this concentration does not have any cytotoxic effect on the human pulmonary cell line (IC50 is 130 µM. Similarly, PVP-AgNPs treatment decreases 80% viability of intracellular bacteria, decreases adherence of A. baumannii to A-549 (40 to 2.2%, and decreases intracellular concentration (20 to 1.3% of A. baumannii. This concludes that PVP-AgNPs can be developed as a substitute for carbapenem to control the infection caused by carbapenem-resistant A. baumannii.

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

Science.gov (United States)

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

2015-01-01

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

Electrical conductivity studies on Ammonium bromide incorporated with Zwitterionic polymer blend electrolyte for battery application

Science.gov (United States)

Parameswaran, V.; Nallamuthu, N.; Devendran, P.; Nagarajan, E. R.; Manikandan, A.

2017-06-01

Solid polymer blend electrolytes are widely studied due to their extensive applications particularly in electrochemical devices. Blending polymer makes the thermal stability, higher mechanical strength and inorganic salt provide ionic charge carrier to enhance the conductivity. In these studies, 50% polyvinyl alcohol (PVA), 50% poly (N-vinyl pyrrolidone) (PVP) and 2.5% L-Asparagine mixed with different ratio of the Ammonium bromide (NH4Br), have been synthesized using solution casting technique. The prepared PVA/PVP/L-Asparagine/doped-NH4Br polymer blend electrolyte films have been characterized by various analytical methods such as FT-IR, XRD, impedance spectroscopy, TG-DSC and scanning electron microscopy. FT-IR, XRD and TG/DSC analysis revealed the structural and thermal behavior of the complex formation between PVA/PVP/L-Asparagine/doped-NH4Br. The ionic conductivity and the dielectric properties of PVA/PVP/L-Asparagine/doped-NH4Br polymer blend electrolyte films were examined using impedance analysis. The highest ionic conductivity was found to be 2.34×10-4 S cm-1 for the m.wt. composition of 50%PVA:50%PVP:2.5%L-Asparagine:doped 0.15 g NH4Br at ambient temperature. Solid state proton battery is fabricated and the observed open circuit voltage is 1.1 V and its performance has been studied.

Clinical effects of conjunctival sac flushing using different concentration of povidoneiodine on corneal epithelium before cataract surgeries

Directory of Open Access Journals (Sweden)

Xue-Lian Gu

2015-10-01

Full Text Available AIM:To determine the most optimal concentration of the safe usage of povidone-iodine(PVP-Iin the flushing to disinfect the conjunctive sac before cataract surgeries, in order to provide a scientific basis for clinical eye surgery work.METHODS:Sixty-two patients with phacoemulsification and intraocular lens implantation in our hospital from October 2012 to October 2014 were randomly divided into 0.25g/L PVP-I group(Ⅰand 5g/L PVP-I group(Ⅱ. Sterilizing effect and the complications postoperative were analyzed.RESULTS:The sterilizing effects of the two groups after flushing conjunctiva sac using different concentrations of PVP-I were both remarkable, but the difference between the two groups was not statistically significant(P>0.05. No endophthalmitis occurred in the two groups. Observing the corneal condition after rinsing, no severe conjunctival hyperemia, corneal edema and other serious complications occurred. There was slightly punctate corneal epithelial shedding in groupⅡ, and the difference was statistically significant(PPCONCLUSION:Using 0.25g/L PVP-I in the conjunctiva sac rinsing before surgeries can inhibit the growth of bacteria in the conjunctival sac, reduce the impact on the corneal epithelium thereby reducing the incidence of postoperative complications and the positive rate of bacterial culture, increasing the comfort degree of patients, bringing a better area for the surgeries.

Correlation between preprocedural MRI findings and the clinical effects of percutaneous vertebroplasty in osteoporotic vertebral compression fractures

International Nuclear Information System (INIS)

Shi Li'na; Wu Chungen; Li Wenbin; Mao Aiwu; Gu Yifeng; Zhang Peilei; Wang Jue; Cheng Yongde

2011-01-01

Objective: to analyze the signal characteristics of preprocedural MRI, to compare the pre-and-post procedural clinical outcomes and to discuss the relationship between preprocedural MRI findings and postprocedural clinical effect of percutaneous vertebroplasty (PVP) therapy in patients with osteoporotic vertebral compression fractures. Methods: PVP procedures were carried out in a total of 52 consecutive patients with 116 compression fractures. The clinical data and the imaging materials were retrospective analyzed. According to the degree and extent of marrow edema demonstrated on sagittal MRI, the patients were divided into three groups: group A, having partial bone marrow edema; group B, showing complete bone marrow edema;and group C having no bone marrow edema. By using independent-samples t-test and paired-samples t-test, the preprocedural and postprocedural pain degree and movement dysfunction severity, which were assessed by means of visual analog scale (VAS) and Oswestry disability index(ODI) respectively, were compared between three groups. The occurrence of complications was observed. Results: After PVP, all patients showed significant relief of pain and obvious improvement of daily activity function (P 0.05). Conclusion: PVP is an effective treatment for osteoporotic vertebral compression fractures with or without bone marrow edema. MRI signal characteristics can predict the therapeutic effect of PVP to a certain degree. And the more extensive the bone marrow edema pattern is, the greater pain relief will be expected. (authors)

Synthesis of Novel (Polymer Blend-Titanium Carbide Nanocomposites and Studying their Characterizations for Piezoelectric Applications

Directory of Open Access Journals (Sweden)

Ahmed Hashima

2018-05-01

Full Text Available Piezoelectric nanocomposites are very important for many applications as a pressure sensors. Fabrication of (polyvinyl alcohol - polyvinyl pyrrolidinone -titanium carbide nanocompos- ites and study their structural, electrical, dielectric and optical properties have been in- vestigated. The effect of adding the TiC nanoparticles on structural, electrical, dielectric and optical properties of polymeric blend has been studied. The results showed that the electrical conductivity of (PVA-PVP-TiC nanocomposites is increasing with the increase of TiC nanoparticles concentrations at room temperature. The FTIR analysis showed there is no interactions between (PVA- PVP polymer blend and TiC nanoparticles. The dielectric studies showed the dielectric constant and dielectric loss of nanocomposites increase with the increase of TiC nanoparticles concentrations and they decrease as frequency increased. The A.C electrical conductivity increases with the increase of TiC nanoparticles concentra- tions and frequency. The results of optical properties showed that the optical absorbance of (PVA- PVP polymer blend increases with the increase of TiC nanoparticles concentrations. The optical constants change with increase in TiC nanoparticles concentrations. The piezo- electric application results of (PVA-PVP-TiC nanocomposites showed that the electrical resistance of (PVA-PVP-TiC nanocomposites decreases with an increase of the pressure which make it is suitable for piezoelectric applications or pressure sensors.

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

Directory of Open Access Journals (Sweden)

K. M. Maheswari

2014-01-01

Full Text Available The present investigation was undertaken with an objective of formulating mouth dissolving films (MDFs of Amlodipine Besylate (AMLO to enhance convenience and compliance of the elderly and pediatric patients for better therapeutic efficacy. Film formers like hydroxy propyl methyl cellulose (HPMC and methyl cellulose (MC along with film modifiers like poly vinyl pyrrolidone K30 (PVP K30, and sodium lauryl sulphate (SLS as solubilizing agents were evaluated. The prepared MDFs were evaluated for in vitro dissolution characteristics, in vitro disintegration time, and their physicomechanical properties. All the prepared MDFs showed good mechanical properties like tensile strength, folding endurance, and % elongation. MDFs were evaluated by means of FTIR, SEM, and X-RD studies. MDFs with 7.5% (w/w of HPMC E3 gave better dissolution properties when compared to HPMC E5, HPMC E15, and MC. MDFs with PVP K30 and SLS gave superior dissolution properties when compared to MDFs without PVP K30 and SLS. The dissolution properties of MDFs with PVP K30 were superior when compared to MDFs with SLS. In the case of F3 containing 7.5% of HPMC E3 and 0.04% of PVP K30, complete and faster release was observed within 60 sec when compared to other formulations. Release kinetics data reveals diffusion is the release mechanism.

Assessment of the field performance of a photovoltaic pumping ...

African Journals Online (AJOL)

The results imply that simple regular maintenance of the system such as dust removal from solar array may reasonably increase the performance of PVP systems. The overall efficiency of the PVP system (1.23 %) was calculated based on the observed and simulated data and found to be appreciably lower than the typical ...

Radiation effects on components of orally administrated medicines

International Nuclear Information System (INIS)

Akhmatovich-Shmajke, T.; Yuz'byak, Kh.; Ovcharchik, A.

1976-01-01

Physicochemical changes occuring in starch, lactose, sucrose, gum arabic, talc, polyvinylpyrrolidone (PVP), and magnesium stearate irradiated on an electronic linear accelerator type LUE-13/9 were studied. Bond breakage in sugars and molecular degradation in starch and PVP were noted. Paramagnetic centers were found to form in most of the test substances. (author)

Percutaneous vertebroplasty in the management of vertebral osteoporotic fractures. Short-term, mid-term and long-term follow-up of 285 patients

International Nuclear Information System (INIS)

Masala, Salvatore; Mammucari, Matteo; Angelopoulos, Georgios; Fiori, Roberto; Massari, Francesco; Simonetti, Giovanni; Faria, Skerdilajd

2009-01-01

To evaluate the short-term, mid-term and long-term follow-up of 285 patients who had undergone percutaneous vertebroplasty (PVP) for osteoporotic vertebral compression fracture (VCF) in our department from 2003 to 2006, and, particularly, to analyse our data on the safety and the usefulness of PVP for durable pain reduction, mobility improvement and the need for analgesic drugs. Follow-up analysis was made through a questionnaire completed by the patients before and after PVP (1 week, 1 year and 3 years). The results are reported by subdivision of patients into groups (by gender, age and number of treated vertebrae), with special reference to pain management, drug administration and quality of life. All patients (285) were followed up for 1 week, 186 for 12 months, and 68 patients were followed up for 3 years. One week after PVP all patients reported normal ambulation (with or without pain), and more than 95% were able to perform activities of daily living (ADL) either without pain or with mild pain. There was no difference in pain relief between the genders after 1 week's follow up, but after 3 years better analgesia results were observed in women. There was no statistically significant difference in the visual analogue scale (VAS) values before PVP between age groups (P = 0.7) and gender (P = 0.4); Patients younger than 75 years had better outcomes than did older ones (>75 years) at 1 week and 1 year follow up. Patients also reported significant reduction in drug therapy for pain. PVP is a safe and useful procedure for the treatment of vertebral osteoporotic fractures. It produces enduring pain reduction, improves patients' mobility and decreases the need for analgesic drugs. (orig.)

Preparation and characterization of polymer nanocomposites coated magnetic nanoparticles for drug delivery applications

Energy Technology Data Exchange (ETDEWEB)

Prabha, G., E-mail: gprabhagovinn@gmail.com; Raj, V., E-mail: alaguraj2@rediffmail.com

2016-06-15

In the present research work, the anticancer drug ‘curcumin’ is loaded with Chitosan (CS)-polyethylene glycol (PEG)-polyvinylpyrrolidone (PVP) (CS-PEG-PVP) polymer nanocomposites coated with superparamagnetic iron oxide (Fe{sub 3}O{sub 4}) nanoparticles. The system can be used for targeted and controlled drug delivery of anticancer drugs with reduced side effects and greater efficiency. The prepared nanoparticles were characterized by Fourier transmission infrared spectroscopy (FTIR), vibrating sample magnetometry (VSM), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Curcumin drug loaded Fe{sub 3}O{sub 4}-CS, Fe{sub 3}O{sub 4}-CS-PEG and Fe{sub 3}O{sub 4}-CS-PEG-PVP nanoparticles exhibited the mean particle size in the range of 183–390 nm with a zeta potential value of 26–41 mV as measured using Malvern Zetasizer. The encapsulation efficiency, loading capacity and in-vitro drug release behavior of curcumin drug loaded Fe{sub 3}O{sub 4}-CS, Fe{sub 3}O{sub 4}-CS-PEG and Fe{sub 3}O{sub 4}-CS-PEG-PVP nanoparticles were studied using UV spectrophotometer. Besides, the cytotoxicity of the prepared nanoparticles using MTT assay was also studied. The curcumin drug release was examined at different pH medium and it was proved that the drug release depends upon the pH medium in addition to the nature of matrix. - Highlights: • The considered drug carrier Fe{sub 3}O{sub 4}-CS-PEG-PVP nanoparticles were prepared and entrapping (Curcumin). • The amount of the drug had great effect on the drug LC and EE and zeta potential Nanocomposites. • The Curcumin- loaded Fe{sub 3}O{sub 4}-CS, Fe{sub 3}O{sub 4}-CS-PEG and Fe{sub 3}O{sub 4}-CS-PEG-PVP nanocomposites showed pH responsive drug release.

Preparation and characterization of polymer nanocomposites coated magnetic nanoparticles for drug delivery applications

International Nuclear Information System (INIS)

Prabha, G.; Raj, V.

2016-01-01

In the present research work, the anticancer drug ‘curcumin’ is loaded with Chitosan (CS)-polyethylene glycol (PEG)-polyvinylpyrrolidone (PVP) (CS-PEG-PVP) polymer nanocomposites coated with superparamagnetic iron oxide (Fe 3 O 4 ) nanoparticles. The system can be used for targeted and controlled drug delivery of anticancer drugs with reduced side effects and greater efficiency. The prepared nanoparticles were characterized by Fourier transmission infrared spectroscopy (FTIR), vibrating sample magnetometry (VSM), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Curcumin drug loaded Fe 3 O 4 -CS, Fe 3 O 4 -CS-PEG and Fe 3 O 4 -CS-PEG-PVP nanoparticles exhibited the mean particle size in the range of 183–390 nm with a zeta potential value of 26–41 mV as measured using Malvern Zetasizer. The encapsulation efficiency, loading capacity and in-vitro drug release behavior of curcumin drug loaded Fe 3 O 4 -CS, Fe 3 O 4 -CS-PEG and Fe 3 O 4 -CS-PEG-PVP nanoparticles were studied using UV spectrophotometer. Besides, the cytotoxicity of the prepared nanoparticles using MTT assay was also studied. The curcumin drug release was examined at different pH medium and it was proved that the drug release depends upon the pH medium in addition to the nature of matrix. - Highlights: • The considered drug carrier Fe 3 O 4 -CS-PEG-PVP nanoparticles were prepared and entrapping (Curcumin). • The amount of the drug had great effect on the drug LC and EE and zeta potential Nanocomposites. • The Curcumin- loaded Fe 3 O 4 -CS, Fe 3 O 4 -CS-PEG and Fe 3 O 4 -CS-PEG-PVP nanocomposites showed pH responsive drug release.

Semi-interpenetrating networks based on POLY(N-isopropyl acrilamide and POLY(N-vinylpyrrolidone

Directory of Open Access Journals (Sweden)

Žugić Dragana

2007-01-01

Full Text Available Three series of semi-interpenetrating polymer networks based on cross-linked poly(N-isopropylacrylamide, PNIPA, and 1, 2 and 3 wt% of linear poly(N-vinylpyrrolidone, PVP, were synthesized in order to improve the mechanical properties of PNIPA gels. The effect of the incorporation of the linear PVP polymer into the temperature responsive networks on the phase transition temperature, swelling behavior and mechanical properties was studied. Polymer networks with four different crosslinking densities were prepared with various molar ratios (25/1 to 100/1 of the monomer (N-isopropylacrylamide to the cross linker (N,N'-methylene-bisacrylamide. The hydrogels were characterized by determination of the equilibrium degree of swelling at 25 °C, the dynamic shear modulus and the effective crosslinking density, as well as the ultimate hydrogel properties, such as the tensile strength and elongation at break. Furthermore, the deswelling kinetics of the hydrogels was also studied by measuring their water retention capacity. The inclusion of the linear hydrophilic PVP in the PNIPA networks increased the equilibrium degree of swelling, the highest values of which were obtained for samples with 2 and 3 wt% of PVP and the NIPA/MBA molar ratio of 75/1 and 100/1. The highest reinforcement effect, evaluated from the ratio of G'red(semi-IPN to G'red(PNIPA, was obtained by incorporation of 2 wt% PVP. The tensile strength of the semi-IPNs reinforced with linear PVP was higher than that of the PNIPA networks. The elongation at break of these semi-IPNs varied between 22 and 55%, which are 22^11% larger than those for single PNIPA networks. The tensile measurements confirmed that the presence of 2 wt% of the linear polymer significantly reinforced the PNIPA network.

[Experiences in the treatment of benign prostatic hyperplasia with high power potassium-titanyl-phosphate (KTP) laser].

Science.gov (United States)

Lipiński, Marek I; Peszyński-Drews, Cezary; Jeromin, Marek Z; Jeromin, Leszek M

2006-01-01

Benign prostatic hyperplasia (BPH) exist in about 70% men after 60 years old. High power KTP laser is a new tool for the treatment of BPH. 49 men were treated by photoselective vaporisation of the prostate (PVP) from August 2003 to May 2004. Thirty patients with follow-up period longer than 12 weeks (12 to 26 weeks) were analyzed. Preoperative prostate volume ranged from 31 to 136 cc. PSA range, estimated before treatment, was normal in all patients (pts). International Prostate Symptom Score (I-PSS) estimated before treatment was over 24 and Quality of Life (QoL) was over 3 in all pts. The maximum peak urinary flow (Qmax) before treatment ranged from 7.2 to 14.1 ml/s. One patient was catheterized with Foley catheter at the finish of the procedure. Two pts required catheterization in the first day after treatment. In two pts increasing of body temperature to 38 degrees C was observed in the first day after treatment. Twenty four hours after treatment haematuria required catheterization was observed in one patient. Seven days after treatment in 4 pts massive haematuria was observed (two required hospitalisation). In one patient because of urinary retention 4 weeks after PVP transurethral resection of the prostate was performed. Four weeks after PVP I-PSS decreased from 24 to 20 and after 12 weeks to 15. The Qmax increased and ranged from 11.3 ml/s to 17.1 ml/s 4 weeks after PVP and 12 weeks after PVP ranged from 15.1 to 22.8 ml/s. Photoselective vaporization of the prostate reduces I-PSS in all patients 12 weeks after procedure. Short follow-up period and a limited number of patients in study group cannot lead to ultimate conclusions. However the results encourage to undertaking further studies on PVP for the treatment of BPH.

Plasmakinetic enucleation of prostate versus 160-W laser photoselective vaporization for the treatment of benign prostatic hyperplasia

Directory of Open Access Journals (Sweden)

Si-Jun Wang

2017-01-01

Full Text Available To evaluate the safety and efficacy of plasmakinetic enucleation of the prostate (PKEP for the treatment of symptomatic benign prostatic hyperplasia (BPH compared with 160-W lithium triboride laser photoselective vaporization of the prostate (PVP. From February 2011 to July 2012, a prospective nonrandomized study was performed. One-hundred one patients underwent PKEP, and 110 underwent PVP. No severe intraoperative complications were recorded, and none of the patients in either group required a blood transfusion. Shorter catheterization time (38.14 ± 23.64 h vs 72.54 ± 28.38 h, P< 0.001 and hospitalization (2.32 ± 1.25 days vs 4.07 ± 1.23 days, P< 0.001 were recorded in the PVP group. At 12-month postoperatively, the PKEP group had a maintained and statistically improvement in International Prostate Symptom Score (IPSS (4.07 ± 2.07 vs 5.00 ± 2.10; P< 0.001, quality of life (QoL (1.08 ± 0.72 vs 1.35 ± 0.72; P= 0.007, maximal urinary flow rate (Qmax (24.75 ± 5.87 ml s−1 vs 22.03 ± 5.04 ml s−1 ; P< 0.001, postvoid residual urine volume (PVR (14.29 ± 6.97 ml vs 17.00 ± 6.11 ml; P= 0.001, and prostate-specific antigen (PSA value (0.78 ± 0.57 ng ml−1 vs 1.27 ± 1.07 ng ml−1 ; P< 0.001. Both PKEP and PVP relieve low urinary tract symptoms (LUTS due to BPH with low complication rates. PKEP can completely remove prostatic adenoma while the total amount of tissue removed by PVP is less than that can be removed by PKEP. Based on our study of the follow-up, PKEP provides better postoperative outcomes than PVP.

Preparation, property of the complex of carboxymethyl chitosan grafted copolymer with iodine and application of it in cervical antibacterial biomembrane

Energy Technology Data Exchange (ETDEWEB)

Chen, Yu [School of Materials Science and Engineering, Beijing Institute of Technology, Beijing 100081 (China); Yang, Yumin; Liao, Qingping [Zhejiang Sanchuang Biological Technology Co., Ltd., Jiaxing, Zhejiang Province 314031 (China); Yang, Wei [School of Materials Science and Engineering, Beijing Institute of Technology, Beijing 100081 (China); Ma, Wanfeng [Zhejiang Sanchuang Biological Technology Co., Ltd., Jiaxing, Zhejiang Province 314031 (China); Zhao, Jian [Department of Gynaecology and Obstetrics, The First Hospital of Peking University, Beijing 100034 (China); Zheng, Xionggao [School of Materials Science and Engineering, Beijing Institute of Technology, Beijing 100081 (China); Yang, Yang [Zhejiang Sanchuang Biological Technology Co., Ltd., Jiaxing, Zhejiang Province 314031 (China); Chen, Rui [Department of Gynaecology and Obstetrics, The First Hospital of Peking University, Beijing 100034 (China)

2016-10-01

Cervical erosion is one of the common diseases of women. The loop electrosurgical excisional procedure (LEEP) has been used widely in the treatment of the cervical diseases. However, there are no effective wound dressings for the postoperative care to protect the wound area from further infection, leading to increased secretion and longer healing time. Iodine is a widely used inorganic antibacterial agent with many advantages. However, the carrier for stable iodine complex antibacterial agents is lack. In the present study, a novel iodine carrier, Carboxymethyl chitosan-g-(poly(sodium acrylate)-co-polyvinylpyrrolidone) (CMCTS-g-(PAANa-co-PVP), was prepared by graft copolymerization of sodium acrylate (AANa) and N-vinylpyrrolidone (NVP) to a carboxymethyl chitosan (CMCTS) skeleton. The obtained structure could combine prominent property of poly(sodium acrylate) (PAANa) anionic polyelectrolyte segment and good complex property of polyvinylpyrrolidone (PVP) segment to iodine. The bioactivity of CMCTS could also be kept. The properties of the complex, CMCTS-g-(PAANa-co-PVP)-I{sub 2}, were studied. The in vitro experiment shows that it has broad-spectrum bactericidal effects to virus, fungus, gram-positive bacteria and gram-negative bacteria. A CMCTS-g-(PAANa-co-PVP)-I{sub 2} complex contained cervical antibacterial biomembrane (CABM) was prepared. The iodine release from the CABM is pH-dependent. The clinic trial results indicate that CABM has better treatment effectiveness than the conventional treatment in the postoperative care of the LEEP operation. - Highlights: • The multifunctional iodine complexing carrier CMCTS-g-(PAANa-co-PVP) was prepared. • CMCTS-g-(PAANa-co-PVP)-I{sub 2} with high antibacterial property and bio-safety was studied. • By compositing it with CMCTS and gelatin further, CABM with multifunction was deduced. • The releasing properties of the activated iodine from CABM showed pH sensitivity. • CABM showed good treating effect for

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

Science.gov (United States)

Prasad, Dev; Chauhan, Harsh; Atef, Eman

2016-03-07

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

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

International Nuclear Information System (INIS)

Xiao, Jianghong; Li, Yan; Jiang, Qingfeng; Sun, Lan; Henderson Jr, Fraser; Wang, Yongsheng; Jiang, Xiaoqin; Li, Guangjun; Chen, Nianyong

2013-01-01

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

Labeling transplanted mice islet with polyvinylpyrrolidone coated superparamagnetic iron oxide nanoparticles for in vivo detection by magnetic resonance imaging

Energy Technology Data Exchange (ETDEWEB)

Huang Hai; Xie Qiuping; Kang Muxing; Zhang Bo; Wu Yulian [Department of Surgery, 2nd Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou 310009 (China); Zhang Hui; Chen Jin; Zhai Chuanxin; Yang Deren [State Key Lab of Silicon Materials and Department of Materials Science and Engineering, Zhejiang University, Hangzhou 310027 (China); Jiang Biao, E-mail: wuyulian@medmail.com.c, E-mail: yulianwu2003@yahoo.c [Department of Radiology, 2nd Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou 310009 (China)

2009-09-09

Superparamagnetic iron oxide nanoparticles (SPIO) are emerging as a novel probe for noninvasive cell tracking with magnetic resonance imaging (MRI) and have potential wide usage in medical research. In this study, we have developed a method using high-temperature hydrolysis of chelate metal alkoxide complexes to synthesize polyvinylpyrrolidone coated iron oxide nanoparticles (PVP-SPIO), as a biocompatible magnetic agent that can efficiently label mice islet {beta}-cells. The size, crystal structure and magnetic properties of the as-synthesized nanoparticles have been characterized. The newly synthesized PVP-SPIO with high stability, crystallinity and saturation magnetization can be efficiently internalized into {beta}-cells, without affecting viability and function. The imaging of 100 PVP-SPIO-labeled mice islets in the syngeneic renal subcapsular model of transplantation under a clinical 3.0 T MR imager showed high spatial resolution in vivo. These results indicated the great potential application of the PVP-SPIO as an MRI contrast agent for monitoring transplanted islet grafts in the clinical management of diabetes in the near future.

Radiation synthesis of superabsorbent CMC based hydrogels for agriculture applications

International Nuclear Information System (INIS)

Raafat, Amany I.; Eid, Mona; El-Arnaouty, Magda B.

2012-01-01

A series of superabsorbent hydrogel based on carboxymethylcellulose (CMC) and polyvinylpyrrolidone (PVP) crosslinked with gamma irradiation have been proposed for agriculture application. The effect of preparation conditions such as feed solution composition and absorbed irradiation dose on the gelation and swelling degree was evaluated. The structure and the morphology of the superabsorbent CMC/PVP hydrogel were characterized using Fourier transform infrared spectroscopy technique (FTIR), and scanning electron microscope (SEM). Effect of ionic strength and cationic and anionic kinds on the swelling behavior of the obtained hydrogel was investigated. Urea as an agrochemical model was loaded onto the obtained hydrogel to provide nitrogen (N) nutrients. The water retention capability and the urea release behavior of the CMC/PVP hydrogels were investigated. It was found that, the obtained CMC/PVP hydrogels have good swelling degree that greatly affected by its composition and absorbed dose. The swelling was also extremely sensitive to the ionic strength and cationic kind. Owing to its considerable slow urea release, good water retention capacity, being economical, and environment-friendly, it might be useful for its application in agriculture field.

Radiation synthesis of superabsorbent CMC based hydrogels for agriculture applications

Science.gov (United States)

Raafat, Amany I.; Eid, Mona; El-Arnaouty, Magda B.

2012-07-01

A series of superabsorbent hydrogel based on carboxymethylcellulose (CMC) and polyvinylpyrrolidone (PVP) crosslinked with gamma irradiation have been proposed for agriculture application. The effect of preparation conditions such as feed solution composition and absorbed irradiation dose on the gelation and swelling degree was evaluated. The structure and the morphology of the superabsorbent CMC/PVP hydrogel were characterized using Fourier transform infrared spectroscopy technique (FTIR), and scanning electron microscope (SEM). Effect of ionic strength and cationic and anionic kinds on the swelling behavior of the obtained hydrogel was investigated. Urea as an agrochemical model was loaded onto the obtained hydrogel to provide nitrogen (N) nutrients. The water retention capability and the urea release behavior of the CMC/PVP hydrogels were investigated. It was found that, the obtained CMC/PVP hydrogels have good swelling degree that greatly affected by its composition and absorbed dose. The swelling was also extremely sensitive to the ionic strength and cationic kind. Owing to its considerable slow urea release, good water retention capacity, being economical, and environment-friendly, it might be useful for its application in agriculture field.

Radiation synthesis of superabsorbent CMC based hydrogels for agriculture applications

Energy Technology Data Exchange (ETDEWEB)

Raafat, Amany I., E-mail: ismaelraafat_a@hotmail.com [Polymer Chemistry Department, National Center for Radiation Research and Technology, P.O. Box 29, Nasr City, Cairo (Egypt); Eid, Mona; El-Arnaouty, Magda B. [Polymer Chemistry Department, National Center for Radiation Research and Technology, P.O. Box 29, Nasr City, Cairo (Egypt)

2012-07-15

A series of superabsorbent hydrogel based on carboxymethylcellulose (CMC) and polyvinylpyrrolidone (PVP) crosslinked with gamma irradiation have been proposed for agriculture application. The effect of preparation conditions such as feed solution composition and absorbed irradiation dose on the gelation and swelling degree was evaluated. The structure and the morphology of the superabsorbent CMC/PVP hydrogel were characterized using Fourier transform infrared spectroscopy technique (FTIR), and scanning electron microscope (SEM). Effect of ionic strength and cationic and anionic kinds on the swelling behavior of the obtained hydrogel was investigated. Urea as an agrochemical model was loaded onto the obtained hydrogel to provide nitrogen (N) nutrients. The water retention capability and the urea release behavior of the CMC/PVP hydrogels were investigated. It was found that, the obtained CMC/PVP hydrogels have good swelling degree that greatly affected by its composition and absorbed dose. The swelling was also extremely sensitive to the ionic strength and cationic kind. Owing to its considerable slow urea release, good water retention capacity, being economical, and environment-friendly, it might be useful for its application in agriculture field.

Eco-Friendly Superwetting Material for Highly Effective Separations of Oil/Water Mixtures and Oil-in-Water Emulsions.

Science.gov (United States)

Wang, Chih-Feng; Yang, Sheng-Yi; Kuo, Shiao-Wei

2017-02-20

Because the treatment of oily wastewater, generated from many industrial processes, has become an increasing environmental concern, the search continues for simple, inexpensive, eco-friendly, and readily scalable processes for fabricating novel materials capable of effective oil/water separation. In this study we prepared an eco-friendly superhydrophilic and underwater superoleophobic polyvinylpyrrolidone (PVP)-modified cotton that mediated extremely efficient separations of mixtures of oil/water and oil/corrosive solutions. This PVP-modified cotton exhibited excellent antifouling properties and could be used to separate oil/water mixtures continuously for up to 20 h. Moreover, the compressed PVP-modified cotton could separate both surfactant-free and -stabilized oil-in-water emulsions with fluxes of up to 23,500 L m -2 h -1 bar -1 -a level one to two orders of magnitude higher than that possible when using traditional ultrafiltration membranes having similar rejection properties. The high performance of our PVP-modified cotton and its green, low-energy, cost-effective preparation suggest its great potential for practical applications.

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

Energy Technology Data Exchange (ETDEWEB)

Rafiee, Ezzat, E-mail: ezzat_rafiee@yahoo.com [Department of Inorganic Chemistry, Faculty of Chemistry, Razi University, Kermanshah 67149 (Iran, Islamic Republic of); Institute of Nano Science and Nano Technology, Razi University, Kermanshah 67149 (Iran, Islamic Republic of); Joshaghani, Mohammad [Department of Inorganic Chemistry, Faculty of Chemistry, Razi University, Kermanshah 67149 (Iran, Islamic Republic of); Institute of Nano Science and Nano Technology, Razi University, Kermanshah 67149 (Iran, Islamic Republic of); Abadi, Parvaneh Ghaderi-Shekhi [Institute of Nano Science and Nano Technology, Razi University, Kermanshah 67149 (Iran, Islamic Republic of)

2016-06-15

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

Effect of different plasticizers on poly(N-vinyl-2-pyrrolidone) hydrogels cross-linked by radiation

International Nuclear Information System (INIS)

Alcantara, Mara Tania S.; Giannini, Danielle R.; Brant, Antonio J.C.; Riella, Humberto G.; Lugao, Ademar B.

2011-01-01

The use of hydrogel membranes usually demands polymers capable of forming films with high elastic and flexible properties besides having high water absorption. In terms of improvements of polymer plasticity, addition of special plasticizers to polymers can do it with promising results, although within limits of concentrations. The objective of this study was to evaluate the different effects of poly(enthylene glycol) (PEG) and glycerol as plasticizers on hydrogel membranes synthesized from poly(N-vinyl-2-pyrrolidone) (PVP) as the main polymer in aqueous polymeric solutions. For that, hydrogels of PVP/agar/PEG, PVP/agar/glycerol and without agar or plasticizer were simultaneously synthesized and sterilized by irradiation of mixtures of such products in aqueous solutions, using gamma-rays from 60 Co source at a dose of 25 kGy. The results based on gel fraction, swelling in water, and some mechanical tests suggest that the degree of PVP cross-linking prevailed over the greater hydrophilicity of glycerol compared to that of PEG with regard to the degree of swelling of the hydrogels. (author)

Radiation stability of resveratrol in immobilization on poly vinyl pyrrolidone hydrogel dressing for dermatological use

International Nuclear Information System (INIS)

Momesso, Roberta G.R.A.P.; Moreno, Carolina S.; Rogero, Sizue O.; Rogero, Jose R.; Spencer, Patrick J.; Lugao, Ademar B.

2010-01-01

The polyphenol trans-resveratrol is a natural phytoalexin, which is found in red wine and in a wide variety of plant species. Resveratrol displays a wide array of biological activities, such as modulation of lipid metabolism, anti-inflammatory and antioxidant activities. This active compound immobilized in polyvinylpyrrolidone (PVP) hydrogel could be very interesting for topical administration, as a dressing form for dermatological use. However, PVP hydrogel obtained by radiation-induced crosslinking can cause undesirable hydrolysis reactions in the active compound. The aim of this work was to verify the resveratrol stability after irradiation at 0.5 and 1 kGy in the presence of ethanol, methanol or tert-butyl alcohol. The integrity of these samples was compared to unirradiated resveratrol by HPLC. The PVP hydrogel matrix was characterized by gel fraction, swelling and in vitro biocompatibility test. The results of gel fraction and swelling degree were approximately 90% and 1600%, respectively. The cytotoxicity assay showed absence of toxicity for this formulation after crosslinking and sterilization, indicating that the PVP hydrogel formulation was appropriate for resveratrol immobilization to produce a dressing for dermatological use.

Radiation stability of resveratrol in immobilization on poly vinyl pyrrolidone hydrogel dressing for dermatological use

Energy Technology Data Exchange (ETDEWEB)

Momesso, Roberta G.R.A.P., E-mail: robertapassarelli@yahoo.com.b [IPEN/CNEN-SP-Instituto de Pesquisas Energeticas e Nucleares, Avenida Professor Lineu Prestes, 2242, Cidade Universitaria, Sao Paulo, SP, CEP 05508-000 (Brazil); Moreno, Carolina S.; Rogero, Sizue O.; Rogero, Jose R.; Spencer, Patrick J.; Lugao, Ademar B. [IPEN/CNEN-SP-Instituto de Pesquisas Energeticas e Nucleares, Avenida Professor Lineu Prestes, 2242, Cidade Universitaria, Sao Paulo, SP, CEP 05508-000 (Brazil)

2010-03-15

The polyphenol trans-resveratrol is a natural phytoalexin, which is found in red wine and in a wide variety of plant species. Resveratrol displays a wide array of biological activities, such as modulation of lipid metabolism, anti-inflammatory and antioxidant activities. This active compound immobilized in polyvinylpyrrolidone (PVP) hydrogel could be very interesting for topical administration, as a dressing form for dermatological use. However, PVP hydrogel obtained by radiation-induced crosslinking can cause undesirable hydrolysis reactions in the active compound. The aim of this work was to verify the resveratrol stability after irradiation at 0.5 and 1 kGy in the presence of ethanol, methanol or tert-butyl alcohol. The integrity of these samples was compared to unirradiated resveratrol by HPLC. The PVP hydrogel matrix was characterized by gel fraction, swelling and in vitro biocompatibility test. The results of gel fraction and swelling degree were approximately 90% and 1600%, respectively. The cytotoxicity assay showed absence of toxicity for this formulation after crosslinking and sterilization, indicating that the PVP hydrogel formulation was appropriate for resveratrol immobilization to produce a dressing for dermatological use.

Labeling transplanted mice islet with polyvinylpyrrolidone coated superparamagnetic iron oxide nanoparticles for in vivo detection by magnetic resonance imaging

International Nuclear Information System (INIS)

Huang Hai; Xie Qiuping; Kang Muxing; Zhang Bo; Wu Yulian; Zhang Hui; Chen Jin; Zhai Chuanxin; Yang Deren; Jiang Biao

2009-01-01

Superparamagnetic iron oxide nanoparticles (SPIO) are emerging as a novel probe for noninvasive cell tracking with magnetic resonance imaging (MRI) and have potential wide usage in medical research. In this study, we have developed a method using high-temperature hydrolysis of chelate metal alkoxide complexes to synthesize polyvinylpyrrolidone coated iron oxide nanoparticles (PVP-SPIO), as a biocompatible magnetic agent that can efficiently label mice islet β-cells. The size, crystal structure and magnetic properties of the as-synthesized nanoparticles have been characterized. The newly synthesized PVP-SPIO with high stability, crystallinity and saturation magnetization can be efficiently internalized into β-cells, without affecting viability and function. The imaging of 100 PVP-SPIO-labeled mice islets in the syngeneic renal subcapsular model of transplantation under a clinical 3.0 T MR imager showed high spatial resolution in vivo. These results indicated the great potential application of the PVP-SPIO as an MRI contrast agent for monitoring transplanted islet grafts in the clinical management of diabetes in the near future.

[Physical self-concept and teenagers with intellectual disability: age, sex, and weight category effects].

Science.gov (United States)

Bégarie, Jérôme; Maïano, Christophe; Ninot, Grégory

2011-03-01

To study the effects of age, sex, weight, and their interactions on global self-esteem (GSE) and physical self-concept in teenagers with intellectual disability (ID). A sample of 353 teenagers with ID, aged 12 to 18 years, participated in this study. The Very Short Form of the Physical Self-Inventory—for adolescents with ID (PSI-VSF-ID) was used to assess GSE and physical self-perceptions (physical value perceived [PVP], sport skills [SS], physical condition, physical appearance, and strength). Multivariate covariance analyses show: (i) lower GSE and physical self levels (except for PVP) in females, compared with males; (ii) reduced GSE, PVP, SS, and perceived physical appearance (PPA) scores during adolescence; (iii) lower GSE, PVP, and PPA scores in obese adolescents, compared with overweight or normal weight peers; and (iv) lower PPA scores in obese females, compared with other teenagers. The sex and age results are almost identical to those for the general population, according to the literature. However, they are far from the main effect in the weight category.

Biochars as Innovative Humidity Sensing Materials

Directory of Open Access Journals (Sweden)

Daniele Ziegler

2017-12-01

Full Text Available In this work, biochar-based humidity sensors were prepared by drop-coating technique. Polyvinylpyrrolidone (PVP was added as an organic binder to improve the adhesion of the sensing material onto ceramic substrates having platinum electrodes. Two biochars obtained from different precursors were used. The sensors were tested toward relative humidity (RH at room temperature and showed a response starting around 5 RH%, varying the impedance of 2 orders of magnitude after exposure to almost 100% relative humidity. In both cases, biochar materials are behaving as p-type semiconductors under low amounts of humidity. On the contrary, for higher RH values, the impedance decreased due to water molecules adsorption. When PVP is added to SWP700 biochar, n-p heterojunctions are formed between the two semiconductors, leading to a higher sensitivity at low RH values for the sensors SWP700-10% PVP and SWP700-20% PVP with respect to pure SWP700 sensor. Finally, response and recovery times were both reasonably fast (in the order of 1 min.

Optimization of Photosensitized Tryptophan Oxidation in the Presence of Dimegin-Polyvinylpyrrolidone-Chitosan Systems.

Science.gov (United States)

Solovieva, Anna B; Kardumian, Valeria V; Aksenova, Nadezhda A; Belovolova, Lyudmila V; Glushkov, Mikhail V; Bezrukov, Evgeny A; Sukhanov, Roman B; Kotova, Svetlana L; Timashev, Peter S

2018-05-23

By the example of a model process of tryptophan photooxidation in the aqueous medium in the presence of a three-component photosensitizing complex (porphyrin photosensitizer-polyvinylpyrrolidone- chitosan, PPS-PVP-CT) in the temperature range of 20-40 °С, we have demonstrated a possibility of modification of such a process by selecting different molar ratios of the components in the reaction mixture. The actual objective of this selection is the formation of a certain PPS-PVP-CT composition in which PVP macromolecules would coordinate with PPS molecules and at the same time practically block the complex binding of PPS molecules with chitosan macromolecules. Such blocking allows utilization of the bactericidal properties of chitosan to a greater extent, since chitosan is known to depress the PPS photosensitizing activity in PPS-PVP-CT complexes when using those in photodynamic therapy (PDT). The optimal composition of photosensitizing complexes appears to be dependent on the temperature at which the PDT sessions are performed. We have analyzed the correlations of the effective rate constants of tryptophan photooxidation with the photophysical characteristics of the formed complexes.

Amphiphilic Fluorinated Block Copolymer Synthesized by RAFT Polymerization for Graphene Dispersions

Directory of Open Access Journals (Sweden)

Hyang Moo Lee

2016-03-01

Full Text Available Despite the superior properties of graphene, the strong π–π interactions among pristine graphenes yielding massive aggregation impede industrial applications. For non-covalent functionalization of highly-ordered pyrolytic graphite (HOPG, poly(2,2,2-trifluoroethyl methacrylate-block-poly(4-vinyl pyridine (PTFEMA-b-PVP block copolymers were prepared by reversible addition-fragmentation chain transfer (RAFT polymerization and used as polymeric dispersants in liquid phase exfoliation assisted by ultrasonication. The HOPG graphene concentrations were found to be 0.260–0.385 mg/mL in methanolic graphene dispersions stabilized with 10 wt % (relative to HOPG PTFEMA-b-PVP block copolymers after one week. Raman and atomic force microscopy (AFM analyses revealed that HOPG could not be completely exfoliated during the sonication. However, on-line turbidity results confirmed that the dispersion stability of HOPG in the presence of the block copolymer lasted for one week and that longer PTFEMA and PVP blocks led to better graphene dispersibility. Force–distance (F–d analyses of AFM showed that PVP block is a good graphene-philic block while PTFEMA is methanol-philic.

PENGARUH POLIVINILPIROLIDON K-30 TERHADAP PENINGKATAN LAJU DISOLUSI ANDROGRAFOLIDA DENGAN SISTEM DISPERSI SOLIDA

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Suharmiati Suharmiati

2012-11-01

Full Text Available Andrographolide is the main constituent of Andrographis paniculata Ness which was poorly soluble in water. As diterpenoid lactone andrographolide has many biological activity, some of them ara immunostimulant, antimalaria, hepatoprotector and anti mutagenic. The objectives of this study were to find out influence of polyvinylpirrolidon (PVP K-30 to increase dissolution rate of andrographolide by solid dispersion in water and dissolution media pH 8,0. In this research andrographolide were divided in 6 groups that are physical mixture and solid dispersion by ratio 1:3; 1:5 and 1:9. Result of these study showed that the X-ray difraction patterns of physical mixture have crystal intensity as same as andrographolide crystal. But solid dispersion showed lower intensity. The solid dispersion system increase dissolution rate of andrographolide isolate. Increasing of dissolution rate a function of the ratio of drug to PVP used. Studies of dissolution rate have shown that coprecipitate of andrographolide-PVP K-30 (1:9 is better combination than 1:5 and 1:3.   Keywords: andrographolide, PVP K-30, solid dispersion and dissolution rate

Video game genre as a predictor of problem use.

Science.gov (United States)

Elliott, Luther; Golub, Andrew; Ream, Geoffrey; Dunlap, Eloise

2012-03-01

This study assessed how problem video game playing (PVP) varies with game type, or "genre," among adult video gamers. Participants (n=3,380) were adults (18+) who reported playing video games for 1 hour or more during the past week and completed a nationally representative online survey. The survey asked about characteristics of video game use, including titles played in the past year and patterns of (problematic) use. Participants self-reported the extent to which characteristics of PVP (e.g., playing longer than intended) described their game play. Five percent of our sample reported moderate to extreme problems. PVP was concentrated among persons who reported playing first-person shooter, action adventure, role-playing, and gambling games most during the past year. The identification of a subset of game types most associated with problem use suggests new directions for research into the specific design elements and reward mechanics of "addictive" video games and those populations at greatest risk of PVP with the ultimate goal of better understanding, preventing, and treating this contemporary mental health problem.

Radiation stability of resveratrol in immobilization on poly vinyl pyrrolidone hydrogel dressing for dermatological use

Science.gov (United States)

Momesso, Roberta G. R. A. P.; Moreno, Carolina S.; Rogero, Sizue O.; Rogero, José R.; Spencer, Patrick J.; Lugão, Ademar B.

2010-03-01

The polyphenol trans-resveratrol is a natural phytoalexin, which is found in red wine and in a wide variety of plant species. Resveratrol displays a wide array of biological activities, such as modulation of lipid metabolism, anti-inflammatory and antioxidant activities. This active compound immobilized in polyvinylpyrrolidone (PVP) hydrogel could be very interesting for topical administration, as a dressing form for dermatological use. However, PVP hydrogel obtained by radiation-induced crosslinking can cause undesirable hydrolysis reactions in the active compound. The aim of this work was to verify the resveratrol stability after irradiation at 0.5 and 1 kGy in the presence of ethanol, methanol or tert-butyl alcohol. The integrity of these samples was compared to unirradiated resveratrol by HPLC. The PVP hydrogel matrix was characterized by gel fraction, swelling and in vitro biocompatibility test. The results of gel fraction and swelling degree were approximately 90% and 1600%, respectively. The cytotoxicity assay showed absence of toxicity for this formulation after crosslinking and sterilization, indicating that the PVP hydrogel formulation was appropriate for resveratrol immobilization to produce a dressing for dermatological use.

Inhibition and quenching effect on positronium formation in metal salt doped polymer blend

Science.gov (United States)

Praveena, S. D.; Ravindrachary, V.; Ismayil, Bhajantri, R. F.; Harisha, A.; Guruswamy, B.; Hegde, Shreedatta; Sagar, Rohan N.

2018-04-01

Sodium Bromide (NaBr) doped PVA/PVP (50:50) polymer blend composites were prepared using solution casting technique. Pure PVA/PVP blend and PVA/PVP:NaBr composites were studied using XRD and Positron Annihilation Lifetime Spectroscopy (PALS). XRD study shows increase in amorphous nature of the blend due to the NaBr dopant and PALS studies reveal that the o-Ps lifetime (τ3) and intensity (I3) decreases with increase in NaBr doping level. This shows chemical quenching and inhibition process of positronium (Ps) formation in the composite. Here the electron acceptor (Br-) acts as a strong chemical quencher for positronium formation and same is understood based on the spur model.

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

DEFF Research Database (Denmark)

Mehta, Prina; Justo, Lucas; Walsh, Susannah

2015-01-01

rates variable between 5 and 10 µL/min, applied voltage 4–11 kV). Each side was coated (using a specially designed flip-able well) selectively with a pre-determined morphology and model drug substance. PVP nanoparticles (inner side, to be in contact with the cornea, mean size ... encapsulated with a probe (flourescein dye) and PVP nanofibres (outer side, to be exposed to air and eye lid, mean width size ... on rapid dissolution and contact of PVP model substance matrix. Adapting these findings further for advanced EHDA technologies (encapsulation layering, controllable size and deposition and multi-phase media deposition options) and intrinsic material properties (functional polymers/excipients and advanced...

A facile soft template synthesis and characterization of PbHAsO4 nanocrystals

International Nuclear Information System (INIS)

Xiu Zhiliang; Lue Mengkai; Zhou Guangjun; Gu Feng; Zhang Haiping; Xu Dong; Yuan Duorong

2004-01-01

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

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

International Nuclear Information System (INIS)

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

2015-01-01

To study the influence of polymer matrix on the effective magnetic anisotropy constant and coercivity of magnetic nanoparticles, we have synthesized the Cobalt ferrite/Polyvinylpyrrolidone (PVP) nanocomposites by co-precipitation method in four different processes. In addition the Monte Carlo simulation and law of approach to the saturation magnetization have been applied to achieve the anisotropy constants. The obtained experimental and theoretical results showed a decrease in anisotropy constant relative to the bulk cobalt ferrite. We have showed that the PVP matrix can interact with metal cations and made them approximately immobilized to participate in spinel structure. Hence different anisotropy constants or coercivity were obtained for synthesized nanocomposites. In addition, PVP matrix can attach to the surface of magnetic particles and make them approximately non-interacting. The synthesized samples have been characterized by Fourier transform infrared spectroscopy (FT-IR) and X-ray diffraction (XRD). Magnetic measurements were made at room temperature using a vibrating sample magnetometer (VSM). - Highlights: • We studied the effect of polymer matrix on the coercivity of the CoFe 2 O 4 /PVP nanocomposites. • The polymer matrix decreases the anisotropy of the nanocomposite system. • We have synthesized nanocomposites with approximately the same size, but significantly different coercivity. • We showed that the PVP/CoFe 2 O 4 nanocomposite has the considerable coercivity due to the spin hindrance. • Magnetic properties of nanocomposites simulated by Monte Carlo method

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

Science.gov (United States)

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

2015-11-01

Nostoc flagelliforme is a terrestrial edible cyanobacterium that grows in arid and semi-arid steppes. The continued over-exploitation in the last century has led to a sharp decline of this resource and a severe deterioration of the steppe ecology. Liquid-cultured N. flagelliforme serves as promising algal 'seeds' for resource restoration. In this study, macroscopic (or visible) aquatic-living colonies (MaACs) of N. flagelliforme were developed under weak light and high nitrogen conditions. In a 24 day shake-flask culture, MaACs were propagated by about 4.5-fold in biomass without loss of their macro-morphology; at the same time, the addition of weak UV-B treatment resulted in slightly bigger MaACs. Polyvinylpyrrolidone (PVP) k30, a water-soluble polymer, was used to generate the coating around MaACs, and after full desiccation, the coated MaACs could recover their photosynthetic physiological activity when rehydrated, with 4% PVP k30 for coating being most effective. In contrast, PVP k30-coated microscopic aquatic-living colonies of N. flagelliforme and non-coated MaACs showed no resistance to full desiccation. The macroscopic morphology or structure of MaACs should be crucial for the formation of protection by PVP k30 coating. PVP k30-coated MaACs were more approaching to actual application for resource restoration. © 2015 The Authors. Microbial Biotechnology published by John Wiley & Sons Ltd and Society for Applied Microbiology.

Safety of greenlight photoselective vaporisation of prostate in lower urinary tract symptoms due to benign prostatic hyperplasia in patients using anticoagulants due to cardiovascular comorbidities

Directory of Open Access Journals (Sweden)

Basri Cakiroglu

2015-07-01

Full Text Available Lasers have been used in the management of benign prostatic hyperplasia for the last two decades. To be comparable, they should reduce or avoid the immediate and long-term complications of transurethral resection of the prostate (TURP or open prostatectomy (OP, especially bleeding and need for blood transfusion. Although Holmium laser treatment of the prostate was compared frequently in terms of cardiovascular safety with TURP or OP, photoselective vaporisation of the prostate (PVP was not largely evaluated. In this article we analyzed the current literature to see if there is convincing data to support the observation of some authors that use of PVP is associated with increased safety in patients on anticoagulants with cardiovascular comorbidities. With this purpose a Medline search between January 2004 to March 2013 was performed using evidence obtained from randomised trials, well-designed controlled studies without randomisation, individual cohort studies, individual case control studies and case reports Results: In the last 10 years, several case-control and cohort studies have demonstrated the efficacy of PVP as well as its safety in patients with cardiovascular comorbidities using anticoagulants. The results confirmed the overall lower perioperative and postoperative morbidity of PVP, whereas the efficacy was comparable to TURP in the short term, despite a higher reoperation rate. Conclusion: Although it is still developing, PVP with KTP or LBO seems to be a promising alternative to both TURP and OP in terms of cardiovascular safety and in patients using anticoagulants.

Percutaneous vertebroplasty: an experimental study in adult corpses

International Nuclear Information System (INIS)

He Shicheng; Teng Gaojun; Zeng Shuilin; Guo Jinhe; Fang Wen; Zhu Guangyu; Liu Zhentian

2002-01-01

Objective: To investigate the key technique factors and the mechanisms of percutaneous vertebroplasty (PVP). Methods: PMMA was classified into three groups according to the ratio of powder/liquid as 1:1, 3:2 and 2:1. Polymerizing process in vitro was measured respectively in each group, which included 10 samples. Twenty vertebrae from T12-L4 in 4 adult corpses were randomly distributed into 2 groups. In one group, PVP was performed under monitoring by combined CT and C-arm X-ray machines. All vertebrae were dissected into individual vertebra and the ultimate compressive strength was measured in double-blind tests. Results: The period of the polymerizing process and the temperature changes during the polymerizing among 3 groups with different ratio of powder/liquid were significantly different. The ratio of 3/2 was the proper regimen for injection. Punctures were successfully reached in one set of puncture in all vertebrae but one, with 4.5 ml of PMMA in average injected in each vertebra. Pre-vertebral leakage of PMMA was demonstrated in 4 of 20 vertebrae. The ultimate compressive strength increased in 38% in the experimental group compared with that of the control group. Conclusions: Proper ratio of powder/liquid and injection time of PMMA is the key technique for PVP. The puncture route of trans-arch of vertebra is accessible for PVP. It is proven in this study that the ultimate compressive strength of vertebra enhances greatly after PVP

Solubility enhancement of benfotiamine, a lipid derivative of thiamine by solid dispersion technique.

Science.gov (United States)

Patel, S M; Patel, R P; Prajapati, B G

2012-03-01

The present study was aimed to increase the solubility of the poorly water soluble drug benfotiamine using hydrophilic polymers (PVP K-30 and HPMC E4). Solid dispersions were prepared by kneading method. Phase solubility study, in-vitro dissolution of pure drug, physical mixtures and solid dispersions were carried out. PVP and HPMC were found to be effective in increasing the dissolution of Benfotiamine in solid dispersions when compared to pure drug. FT-IR, differential scanning calorimetry and X-ray diffractometry studies were carried out in order to characterize the drug and solid dispersion. To conclude that, the prepared solid dispersion of PVP-30 may to effectively used for the enhancement of solubility of poorly water soluble drugs such as benfotiamine.

Solubility enhancement of benfotiamine, a lipid derivative of thiamine by solid dispersion technique

Directory of Open Access Journals (Sweden)

S M Patel

2012-01-01

Full Text Available The present study was aimed to increase the solubility of the poorly water soluble drug benfotiamine using hydrophilic polymers (PVP K-30 and HPMC E4. Solid dispersions were prepared by kneading method. Phase solubility study, in-vitro dissolution of pure drug, physical mixtures and solid dispersions were carried out. PVP and HPMC were found to be effective in increasing the dissolution of Benfotiamine in solid dispersions when compared to pure drug. FT-IR, differential scanning calorimetry and X-ray diffractometry studies were carried out in order to characterize the drug and solid dispersion. To conclude that, the prepared solid dispersion of PVP-30 may to effectively used for the enhancement of solubility of poorly water soluble drugs such as benfotiamine.

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

International Nuclear Information System (INIS)

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

2012-01-01

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

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

International Nuclear Information System (INIS)

Wang, Xianghong; Yuan, Shuaishuai; Shi, Dean; Yang, Yingkui; Jiang, Tao; Yan, Shunjie; Shi, Hengchong; Luan, Shifang; Yin, Jinghua

2016-01-01

Graphical abstract: - Highlights: • Antifouling and bactericidal capabilities were facilely integrated into a surface via bioinspired coating. • The modification technique was very facile and universal to different types of substrate materials. • The integrated antifouling and bactericidal surfaces have great potential in wound dressing applications. - Abstract: 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.

The Property Value Protection Program - How the Compensation Plan is Working and Evolving to Meet Changing Needs - 13149

International Nuclear Information System (INIS)

Faught, Jeff; Herod, Judy; Mahabir, Alexandra

2013-01-01

The Property Value Protection (PVP) Program offers an innovative approach to address the risk of individual property value loss resulting from the cleanup and long-term management of historic low level radioactive waste in the Port Hope area in Southern Ontario, Canada. This cleanup is taking place through the Port Hope Area Initiative (PHAI), a federally sponsored waste remediation project. The PVP Program came into effect on October 1, 2000, having been established as a key element of the PHAI Legal Agreement between the Government of Canada and the municipalities of Port Hope and Clarington. The PVP Program was designed in direct response to the concern expressed by the agreement's two municipal signatories that protection of local property owners from the risk of property value loss was critical to their acceptance of the Port Hope and Port Granby projects. The PVP Program compensates owners of residential, commercial or industrial properties for a loss in fair market value on the sale or rental of their properties. Increased mortgage refinancing costs and expenses incurred as a result of delayed sales that can be attributed to the Port Hope Area Initiative are also compensated. (authors)

k-Carrageenan/poly vinyl pyrollidone/polyethylene glycol/silver nanoparticles film for biomedical application.

Science.gov (United States)

Fouda, Moustafa M G; El-Aassar, M R; El Fawal, G F; Hafez, Elsayed E; Masry, Saad Hamdy Daif; Abdel-Megeed, Ahmed

2015-03-01

Biopolymer composite film containing k-carrageenan (KC), polyvinyl pyrrolidone (PVP), and polyethylene glycol (PEG) was formulated by dissolving KC and PVP in water containing PEG. Silver nanoparticles (AgNPs), was produced by Honeybee and added to solution. Finally, all solutions were poured onto dishes and dried overnight at 40°C to form the final films. Tensile strength (TS) and elongation (E %) is evaluated. The water contact angle is inspected. Thermal properties (TGA) and swelling behavior for water were considered. Fungal activity is also examined. Morphology of all films was also explored using scanning electron microscope. AgNPs induced significant hydrophilicity to KC-PVP-PEG film with contact angle of 41.6 and 34.7 for KC-PVP-PEG-AgNPs. Films with AgNPs exhibited higher thermal stability and strength properties than other films without. Films with AgNPs explore lower swelling behavior than other films without. Both SEM and EDX proved the deposition of AgNPs on the surface of films. Films with AgNPs showed higher activity against pathogenic fungi compared with the chemical fungicide; fluconazole. Copyright © 2014 Elsevier B.V. All rights reserved.

Research on Hydrophilic Nature of Polyvinylpyrrolidone on Polysulfone Membrane Filtration

Science.gov (United States)

Tiron, L. G.; Vlad, M.; Baltă, Ş.

2018-06-01

The membranes used in wastewater filtration are obtained from polymers, this technique is widely applied because of the small installations and low costs as against conventional systems. The polymeric membranes have high mechanical strength and flexibility, but is a challenge to improve in the same time the permeability and retention capacity of the membranes. A process that can improve the membrane properties is the addition of additives to the polymer solution, resulting in noticeable changes in the resulting membrane structure. Polyvinylpyrrolidone (PVP) is a highly hydrophilic polymer, used as a food additive that acts as stabilizer and thickening agent, which brings improvements in membrane properties. This study analyses the effect of polyvinylpyrrolidone (PVP) on the casting solution of the prepared membranes. The polymer solution was prepared from polysulfone (PSf) and N-methyl-2-pyrrolidone (NMP) at different concentrations. The membranes were obtained by phase inversion method. The PSf/PVP/NMP membranes with different concentrations were characterized by contact angle measurements, surface roughness, morphological structure and permeation tests. The results show that the hydrophilic nature of PVP improve the pure water flux, the contact angle and exhibit a higher anti-fouling property.

The influence of sodium salts (iodide, chloride and sulfate) on the formation efficiency of sulfamerazine nanocrystals.

Science.gov (United States)

Lou, Hao; Liu, Min; Qu, Wen; Johnson, James; Brunson, Ed; Almoazen, Hassan

2014-08-01

The purpose of this study is to evaluate the influence of sodium iodide, sodium chloride and sodium sulfate on the formation efficiency of sulfamerazine nanocrystals by wet ball milling. Sulfamerazine was milled using zirconium oxide beads in a solution containing polyvinylpyrrolidone (PVP) and a sodium salt (iodide, chloride or sulfate). Particle size distributions were evaluated by light diffraction before and after milling. High-performance liquid chromatography was utilized to determine the amount of PVP adsorbed onto sulfamerazine surface. Lyophilized nanocrystals were further characterized by differential scanning calorimetry and dissolution testing. Sulfate ion had more profound effect on reducing particle size via milling than iodide or chloride. We linked our findings to Hofmeister ion series, which indicates that sulfate ions tends to break the water structure, increases the surface tension and lowers the solubility of hydrocarbons in water. We hypothesized that the addition of sulfate ions dehydrated the PVP molecules and enhanced its adsorption onto the sulfamerazine particle surfaces. Consequently, the adsorbed PVP helped to stabilize of the nanosuspension. The nanocrystals that were obtained from the lyophilized milled suspensions exhibited a notable increase in dissolution rate. The addition of sodium sulfate enhanced the formation efficiency of sulfamerazine nanocrystals.

The Property Value Protection Program - How the Compensation Plan is Working and Evolving to Meet Changing Needs - 13149

Energy Technology Data Exchange (ETDEWEB)

Faught, Jeff; Herod, Judy; Mahabir, Alexandra [Atomic Energy of Canada Limited, Port Hope, Ontario (Canada)

2013-07-01

The Property Value Protection (PVP) Program offers an innovative approach to address the risk of individual property value loss resulting from the cleanup and long-term management of historic low level radioactive waste in the Port Hope area in Southern Ontario, Canada. This cleanup is taking place through the Port Hope Area Initiative (PHAI), a federally sponsored waste remediation project. The PVP Program came into effect on October 1, 2000, having been established as a key element of the PHAI Legal Agreement between the Government of Canada and the municipalities of Port Hope and Clarington. The PVP Program was designed in direct response to the concern expressed by the agreement's two municipal signatories that protection of local property owners from the risk of property value loss was critical to their acceptance of the Port Hope and Port Granby projects. The PVP Program compensates owners of residential, commercial or industrial properties for a loss in fair market value on the sale or rental of their properties. Increased mortgage refinancing costs and expenses incurred as a result of delayed sales that can be attributed to the Port Hope Area Initiative are also compensated. (authors)

Techno-Economic Feasibility And Cost Analysis Of Solar Water Pumping In Nigeria

International Nuclear Information System (INIS)

Okonta, A.D; Akinwumi, I.O; Siyanbola, W.O.

2004-01-01

Solar photovoltaic Water Pumping (PVP) system is becoming a reliable and cost effective method of supplying potable water to remote rural areas of developing countries. Whoever, the high initial investment cost has hindered it widespread application. This paper has reported the outcome of an economic feasibility and cost analysis survey carried out in Nigeria. It involved the administration of a validated set of questionnaires to randomly selected stratified respondents. The outcomes were analysed using graphical displays, a student t-test statistic and the Statistical Package for Social Sciences (SPSS Version 10.0) the survey showed that private investors sourced their funds mostly form commercial banks and through savings. They do not enjoy any government incentives or subsidy. It was found that he number of modules per system and borehole depths are the major initial cost components and that the mean cost of PVP system in Nigeria between 1999- 2003 is 31,690.91 U$$. The paper recommends the establishment and intensive monitoring of PVP pilot projects in different geographical zones of the country to provide the database for Life-cycle-cost analysis and as feedback for the further development of PVP systems in Nigeria

Outcome of CT-guided vertebroplasty in outpatients with severe vertebral compression fractures

International Nuclear Information System (INIS)

Braun, Markus; Gevargez, Athour; Lange, Silke; Leeuwen, Peter van; Groenemeyer, Dietrich H.W.

2008-01-01

To determine the safety and efficacy of computed tomography (CT)/fluoroscopy-guided percutaneous vertebroplasty (PVP) for the treatment of painful severe osteoporotic compression fractures. In 26 patients with osteoporotic severe and non-severe compression fractures experiencing pain, 55 PVP were performed. Pain relief and improvement of function were estimated using the Visual Analog Scale (VAS), Pain Disability Index (PDI) and Hannover functional ability questionnaire (FFbH) at follow-up examinations at a median of 3 (1-31) days and 6.5 (1-18) months after PVP. Pain relief (VAS and PDI) was significant at first and second follow-up. The improvement of function (FFbH) was statistically significant at the second follow-up. Severity of the compression fractures did not influence these results. There were no clinical complications and no patient required follow-up surgery. PVP is a safe and effective treatment of pain even in severe osteoporotic vertebral body compression fractures. The advantages of CT-guidance in combination with fluoroscopy technique are a minimally invasive precise procedure with high visualization and with low risk, performed cost effective on out patient basis in local anesthesia, leading to an early recovery of individual independence. (orig.)

Polyol synthesis of silver nanoplates: The crystal growth mechanism based on a rivalrous adsorption

International Nuclear Information System (INIS)

Luo Xiaolin; Li Zongxiao; Yuan Chunlan; Chen Yashao

2011-01-01

Highlights: → Silver nanoplates have been successfully synthesized by polyol reduction in the presence of poly (vinylpyrrolidone) (PVP) and HNO 3 . → Due to the discovery of CN - ions in the solution, a mechanism for the anisotropic growth of silver nanoplates is systematically discussed. → TG, FT-IR and SERS were used to provide some direct evidences of rivalrous adsorption between PVP and CN - ions on the surface of the silver crystals. - Abstract: A polyol reducing approach has been applied to synthesize silver nanoplates with an average thickness of 50 nm and edge length of 3 μm in the presence of poly (vinylpyrrolidone) (PVP) and HNO 3 . X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscropy (TEM), and electron diffraction are used to characterize these silver nanoplates. Findings indicate that the nanoplates are single crystals and with their basal plane as (1 1 1) lattice plane. On the basis of the results from thermogravimetric analysis (TG), Fourier transform infrared spectroscopy (FT-IR) and Raman spectroscopy, a crystal growth mechanism based on the rivalrous adsorption between PVP and CN - ions on the surface of silver nanoplates is supposed to explain the crystal anisotropic growth.

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

Energy Technology Data Exchange (ETDEWEB)

Wang, Xianghong [State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (China); Ministry of Education Key Laboratory for the Green Preparation and Application of Functional Materials, Hubei Collaborative Innovation Center for Advanced Organic Chemical Materials, Faculty of Materials Science and Engineering, Hubei University, Wuhan 430062 (China); Yuan, Shuaishuai [State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (China); Shi, Dean, E-mail: deanshi2012@yahoo.com [Ministry of Education Key Laboratory for the Green Preparation and Application of Functional Materials, Hubei Collaborative Innovation Center for Advanced Organic Chemical Materials, Faculty of Materials Science and Engineering, Hubei University, Wuhan 430062 (China); Yang, Yingkui; Jiang, Tao [Ministry of Education Key Laboratory for the Green Preparation and Application of Functional Materials, Hubei Collaborative Innovation Center for Advanced Organic Chemical Materials, Faculty of Materials Science and Engineering, Hubei University, Wuhan 430062 (China); Yan, Shunjie; Shi, Hengchong [State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (China); Luan, Shifang, E-mail: sfluan@ciac.ac.cn [State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (China); Yin, Jinghua [State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (China)

2016-07-01

Graphical abstract: - Highlights: • Antifouling and bactericidal capabilities were facilely integrated into a surface via bioinspired coating. • The modification technique was very facile and universal to different types of substrate materials. • The integrated antifouling and bactericidal surfaces have great potential in wound dressing applications. - Abstract: 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.

Preparation and characterization of chitosan/genipin/poly(N-vinyl-2-pyrrolidone) films for controlled release drugs

Energy Technology Data Exchange (ETDEWEB)

Aldana, Ana Agustina, E-mail: aaldana@fcq.unc.edu.ar [Departamento de Quimica Organica, Facultad de Ciencias Quimicas, Universidad Nacional de Cordoba (UNC), Edificio de Ciencias II, Medina Allende y Haya de la Torre, Ciudad Universitaria, Cordoba 5000 (Argentina); Gonzalez, Agustin, E-mail: agustingonzalez@fcq.unc.edu.ar [Departamento de Quimica Organica, Facultad de Ciencias Quimicas, Universidad Nacional de Cordoba (UNC), Edificio de Ciencias II, Medina Allende y Haya de la Torre, Ciudad Universitaria, Cordoba 5000 (Argentina); Strumia, Miriam C., E-mail: mcs@fcq.unc.edu.ar [Departamento de Quimica Organica, Facultad de Ciencias Quimicas, Universidad Nacional de Cordoba (UNC), Edificio de Ciencias II, Medina Allende y Haya de la Torre, Ciudad Universitaria, Cordoba 5000 (Argentina); Martinelli, Marisa, E-mail: mmartinelli@fcq.unc.edu.ar [Departamento de Quimica Organica, Facultad de Ciencias Quimicas, Universidad Nacional de Cordoba (UNC), Edificio de Ciencias II, Medina Allende y Haya de la Torre, Ciudad Universitaria, Cordoba 5000 (Argentina)

2012-05-15

Highlights: Black-Right-Pointing-Pointer Cross-linked chitosan films using genipin and/or PVP. Black-Right-Pointing-Pointer Propranolol hydrochloride was used like a model drug to release studies. Black-Right-Pointing-Pointer Incorporating PVP improves mechanical and diffusion properties. Black-Right-Pointing-Pointer Ch-Gen 0.10% and Ch-Gen 0.10%-PVP have optimal behavior. - Abstract: The study of the physicochemical and functional properties of chitosan films cross-linked with genipin and poly(N-vinyl-2-pyrrolidone) (PVP) was performed in this work. Cross-linked films were prepared by casting method from acetic acid solutions. The structure and physical properties of the films were analyzed by infrared spectroscopy (FT-IR), nuclear magnetic resonance spectroscopy ({sup 13}C NMR), differential scanning calorimetry (DSC) and mechanical testings. Propranolol hydrochloride was used like a model drug to determine the behavior of drug release from films. The drug release capacity was measured and compared with the degree of cross-linking, mechanical properties and swelling index. There was an appropriate balance of hydrophilicity, mechanical properties and diffusion by the incorporation of PVP into the networks cross-linked with genipin. The combination of both cross-linkers allows obtaining a soft and tough material potentially applicable as a controlled release. This research represents the first report where both cross-linkers, chemical and ionic agents, are used for obtaining films. These studies suggest that the chitosan films prepared here are promising drug delivery systems for buccal application, with thermal stability and acceptable mechanical properties. Buccal films may be preferred in terms of flexibility and comfort.

Use of the co-grinding method to enhance the dissolution behavior of a poorly water-soluble drug: generation of solvent-free drug-polymer solid dispersions.

Science.gov (United States)

Yang, Caiqin; Xu, Xiujuan; Wang, Jing; An, Zhiqian

2012-01-01

The solid dispersion (SD) technique is the most effective method for improving the dissolution rate of poorly water-soluble drugs. In the present work, SDs of the Ca2+ channel blocker dipfluzine (DF) with polyvinylpyrrolidone K30 (PVP) and poloxamer 188 (PLXM) were prepared by the powder solid co-grinding method under a solvent-free condition. The properties of all SDs and physical mixtures were investigated by X-ray diffraction, Fourier-transform infrared, differential scanning calorimetry, scanning electron microscopy, dissolution test, and particles size determination. Eutectic compounds were produced between the DF and PLXM matrix during the co-grinding process, whereas glass suspension formed in the SDs with PVP carrier. Hydrogen bond formation was not observed between DF and carriers and DF was microcrystalline state in the PVP and PLXM matrices. The solubility of DF in different concentration of carriers at 25, 31, and 37°C was investigated; the values obtained were used to calculate the thermodynamic parameters of interaction between DF and carriers. The Gibbs free energy (ΔrGθ) values were negative, indicating the spontaneous nature of dispersing DF into the carriers. Moreover, entropy is the drive force when DF disperses into the matrix of PVP, while, enthalpy-driven dispersing encounters in the PLXM carrier. All the SDs of DF/carriers showed a considerably higher dissolution rate than pure DF and the corresponding physical mixtures. The cumulative dissolution rate at 10 min of the SD with a 1 : 3 DF/carrier ratio increased 5.1-fold for PVP and 5.5-fold for PLXM.

Preparation and characterization of chitosan/genipin/poly(N-vinyl-2-pyrrolidone) films for controlled release drugs

International Nuclear Information System (INIS)

Aldana, Ana Agustina; González, Agustín; Strumia, Miriam C.; Martinelli, Marisa

2012-01-01

Highlights: ► Cross-linked chitosan films using genipin and/or PVP. ► Propranolol hydrochloride was used like a model drug to release studies. ► Incorporating PVP improves mechanical and diffusion properties. ► Ch–Gen 0.10% and Ch–Gen 0.10%–PVP have optimal behavior. - Abstract: The study of the physicochemical and functional properties of chitosan films cross-linked with genipin and poly(N-vinyl-2-pyrrolidone) (PVP) was performed in this work. Cross-linked films were prepared by casting method from acetic acid solutions. The structure and physical properties of the films were analyzed by infrared spectroscopy (FT-IR), nuclear magnetic resonance spectroscopy ( 13 C NMR), differential scanning calorimetry (DSC) and mechanical testings. Propranolol hydrochloride was used like a model drug to determine the behavior of drug release from films. The drug release capacity was measured and compared with the degree of cross-linking, mechanical properties and swelling index. There was an appropriate balance of hydrophilicity, mechanical properties and diffusion by the incorporation of PVP into the networks cross-linked with genipin. The combination of both cross-linkers allows obtaining a soft and tough material potentially applicable as a controlled release. This research represents the first report where both cross-linkers, chemical and ionic agents, are used for obtaining films. These studies suggest that the chitosan films prepared here are promising drug delivery systems for buccal application, with thermal stability and acceptable mechanical properties. Buccal films may be preferred in terms of flexibility and comfort.

Preparation of various hydrogels based on poly (Vinyl pyrrolidone) and poly ethylene glycol using gamma and electron irradiation

International Nuclear Information System (INIS)

Ajji, Z.

2006-11-01

Different hydrogels have been prepared using gamma and electron irradiation; the hydrogels are composed of poly(vinyl pyrolidone) (PVP), poly(ethylene glycol) (PEG). The influence of some process parameters on the properties of the hydrogels has been investigated as: the gel fraction, maximum swelling, swelling kinetics, and mechanical properties. In the first part of this study, hydrogel dressings have been prepared using electron irradiation, and the dressings are composed of poly(vinyl pyrrolidone) (PVP), poly(ethylene glycol) (PEG) and agar. The gel fraction increases with increasing PVP concentration due to increased crosslink density, and decreases with increasing the PEG concentration. PEG seems to act not only as plasticizer but also to modify the gel properties as gelation% and maximum swelling. The prepared hydrogels dressings could be considered as a good barrier against microbes. In the second part, different hydrogels have been prepared based on different concentrations of poly(vinyl pyrrolidone) and using gamma irradiation. The gel fraction and maximum swelling of the hydrogels has been determined. In the third part of the study, different hydrogels have been prepared based on different concentrations of poly(vinyl pyrrolidone) and poly(ethylene glycol) (PEG) with various molecular weights, and using gamma irradiation. The gel fraction and maximum swelling of the hydrogels has been determined. The data show that PEG with low molecular weight needs a high dose for the gelation, and the presence of PVP lowers the needed gelation dose. The maximum swelling decreases with increasing irradiation dose and the PVP concentration, which is due to higher crosslinks between the polymer chains. (author)

Antiproliferative/cytotoxic effects of molecular iodine, povidone-iodine and Lugol's solution in different human carcinoma cell lines.

Science.gov (United States)

Rösner, Harald; Möller, Wolfgang; Groebner, Sabine; Torremante, Pompilio

2016-09-01

Clinical trials have revealed that molecular iodine (I 2 ) has beneficial effects in fibrocystic breast disease and in cyclic mastalgia. Likewise, povidone-iodine (PVP-I), which is widely used in clinical practice as an antiseptic agent following tumour surgery, has been demonstrated to have cytotoxic effects on colon cancer and ascites tumour cells. Our previous study indicated that the growth of breast cancer and seven other human malignant cell lines was variably diminished by I 2 and iodolactones. With the intention of developing an iodine-based anticancer therapy, the present investigations extended these studies by comparing the cytotoxic capacities of I 2 , potassium iodide (KJ), PVP-I and Lugol's solution on various human carcinoma cell lines. Upon staining the cell nuclei with Hoechst 33342, the cell densities were determined microscopically. While KJ alone did not affect cell proliferation, it enhanced the antiproliferative activity of I 2 . In addition, PVP-I significantly inhibited the proliferation of human MCF-7 breast carcinoma, IPC melanoma, and A549 and H1299 lung carcinoma cells in a concentration corresponding to 20 µM I 2 . Likewise, Lugol's solution in concentrations corresponding to 20-80 µM I 2 were observed to reduce the growth of MCF-7 cells. Experiments with fresh human blood samples revealed that the antiproliferative activity of PVP-I and I 2 is preserved in blood plasma to a high degree. These findings suggest that PVP-I, Lugol's solution, and a combination of iodide and I 2 may be potent agents for use in the development of antitumour strategies.

Development of a novel sodium fusidate-loaded triple polymer hydrogel wound dressing: Mechanical properties and effects on wound repair.

Science.gov (United States)

Jin, Sung Giu; Kim, Kyeong Soo; Kim, Dong Wuk; Kim, Dong Shik; Seo, Youn Gee; Go, Toe Gyung; Youn, Yu Seok; Kim, Jong Oh; Yong, Chul Soon; Choi, Han-Gon

2016-01-30

To develop a novel sodium fusidate-loaded triple polymer hydrogel dressing (TPHD), numerious polyvinyl alcohol-based (PVA) hydrogel dressings were prepared with various hydrophilic polymers using the freeze-thaw method, and their hydrogel dressing properties were assessed. Among the hydrophilic polymers tested, sodium alginate (SA) improved the swelling capacity the most, and polyvinyl pyrrolidone (PVP) provided the greatest improvement in bioadhesive stength and mechanical properties. Thus, PVA based-TPHDs were prepared using different ratios of PVP:SA. The effect of selected PVP:SA ratios on the swelling capacity, bioadhesive strength, mechanical properties, and drug release, permeation and deposition characteristics of sodium fusidate-loaded PVA-based TPHDs were assessed. As the ratio of PVP:SA increased in PVA-loaded TPHD, the swelling capacity, mechanical properties, drug release, permeation and deposition were improved. The TPHD containing PVA, PVP, SA and sodium fusidate at the weight ratio of 10/6/1/1 showed excellent hydrogel dressing properties, release, permeation and deposition of drug. Within 24h, 71.8 ± 1.3% of drug was released. It permeated 625.1 ± 81.2 μg/cm(2) through the skin and deposited of 313.8 ± 24.1 μg/cm(2) within 24h. The results of in vivo pharmacodynamic studies showed that sodium fusidate-loaded TPHD was more effective in improving the repair process than was a commercial product. Thus, this sodium fusidate-loaded TPHD could be a novel tool in wound care. Copyright © 2015 Elsevier B.V. All rights reserved.

Novel antiseptic compound OPB-2045G shows potent bactericidal activity against methicillin-resistant Staphylococcus aureus and vancomycin-resistant Enterococcus both in vitro and in vivo: a pilot study in animals.

Science.gov (United States)

Inoue, Yasuhide; Hagi, Akifumi; Nii, Takuya; Tsubotani, Yoshie; Nakata, Hikaru; Iwata, Koushi

2015-01-01

There is a need for new compounds to effectively treat methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Enterococcus (VRE). The novel monobiguanide compound 1-(3,4-dichlorobenzyl)-5-octylbiguanide gluconate (OPB-2045G) has potential bactericidal activity. We sought to elucidate the potency of OPB-2045G bactericidal activity against MRSA and VRE compared to those of chlorhexidine digluconate (CHG) and povidone iodine (PVP-I). In vitro bactericidal activity was analysed using minimum bactericidal concentration (MBC) as the index. The in vivo bactericidal efficacy of OPB-2045G was examined by determining MRSA and VRE contamination of the normal dorsal skin of mice following removal of hair. After a 3 min treatment period, the MBC of OPB-2045G was lower than that of CHG and PVP-I against standard strains and clinical isolates. Additionally, in our in vivo mouse model, the in vivo bactericidal activity of 1.5 % OPB-2045G (a clinically relevant dose) was higher than that of 0.5 % CHG and equivalent to that of 10 % PVP-I against MRSA. Similarly, the in vivo bactericidal activity of OPB-2045G was higher than that of 0.5 % CHG and 10 % PVP-I against VRE. OPB-2045G showed more potent bactericidal activity against MRSA and VRE both in vitro and in vivo compared to CHG and PVP-I, indicating that OPB-2045G may provide better protection against health care-associated infections caused by these pathogens. © 2015 The Authors.

Polyvinylpyrrolidone-Based Bio-Ink Improves Cell Viability and Homogeneity during Drop-On-Demand Printing

Directory of Open Access Journals (Sweden)

Wei Long Ng

2017-02-01

Full Text Available Drop-on-demand (DOD bioprinting has attracted huge attention for numerous biological applications due to its precise control over material volume and deposition pattern in a contactless printing approach. 3D bioprinting is still an emerging field and more work is required to improve the viability and homogeneity of printed cells during the printing process. Here, a general purpose bio-ink was developed using polyvinylpyrrolidone (PVP macromolecules. Different PVP-based bio-inks (0%–3% w/v were prepared and evaluated for their printability; the short-term and long-term viability of the printed cells were first investigated. The Z value of a bio-ink determines its printability; it is the inverse of the Ohnesorge number (Oh, which is the ratio between the Reynolds number and a square root of the Weber number, and is independent of the bio-ink velocity. The viability of printed cells is dependent on the Z values of the bio-inks; the results indicated that the cells can be printed without any significant impairment using a bio-ink with a threshold Z value of ≤9.30 (2% and 2.5% w/v. Next, the cell output was evaluated over a period of 30 min. The results indicated that PVP molecules mitigate the cell adhesion and sedimentation during the printing process; the 2.5% w/v PVP bio-ink demonstrated the most consistent cell output over a period of 30 min. Hence, PVP macromolecules can play a critical role in improving the cell viability and homogeneity during the bioprinting process.

High yield growth of uniform ZnS nanospheres with strong photoluminescence properties

International Nuclear Information System (INIS)

Li, Yuan; Li, Qing; Wu, Huijie; Zhang, Jin; Lin, Hua; Nie, Ming; Zhang, Yu

2013-01-01

Graphical abstract: High-yield ZnS nanospheres with an average diameter of 80 nm were fabricated successfully in aqueous solution at 100 °C by the assistance of surfactant PVP. It was found that PVP plays a crucial role in the formation of uniform ZnS nanospheres. A possible self-assembling growth mechanism was proposed. The UV–vis spectrum indicates that the as-prepared ZnS nanospheres exhibit a dramatic blue-shift. PL spectrum reveals that the ZnS nanospheres have a strong visible emission peak centered at 516 nm with excitation light of 400 nm. Highlights: ► High-yield ZnS nanospheres were generated conveniently in aqueous solution. ► The amount of surfactant PVP plays a crucial role on the morphology and size of the products. ► A tentative explanation for the growth mechanism of ZnS nanospheres was proposed. ► The UV–vis spectrum indicated that the sample exhibits a dramatic blue-shift. ► PL spectrum reveals that ZnS nanospheres have a strong visible emission peak centered at 516 nm with excitation light of 400 nm. - Abstract: High yield ZnS nanospheres were generated conveniently in aqueous solution with the assistance of surfactant polyvinyl pyrrolidone (PVP). The products were characterized by XRD, EDX, XPS, FESEM, TEM and HRTEM. The as-prepared ZnS nanospheres were uniform with an average diameter of 80 nm. The role of PVP in the forming of ZnS nanospheres was investigated. The results indicated that surfactant PVP plays a crucial role on the morphology and size of the products. Moreover, a tentative explanation for the growth mechanism of ZnS nanospheres was proposed. UV–vis and PL absorption spectrum were used to investigate the optical properties of ZnS nanospheres. The UV–vis spectrum indicated that the sample exhibits a dramatic blue-shift. PL spectrum reveals that ZnS nanospheres have a strong visible emission peak centered at 516 nm with excitation light of 400 nm.

Nitroglycerine and patient position effect on central, hepatic and portal venous pressures during liver surgery.

Science.gov (United States)

Sand, L; Lundin, S; Rizell, M; Wiklund, J; Stenqvist, O; Houltz, E

2014-09-01

To reduce blood loss during liver surgery, a low central venous pressure (CVP) is recommended. Nitroglycerine (NG) with its rapid onset and offset can be used to reduce CVP. In this study, the effect of NG on portal and hepatic venous pressures (PVP and HVP) in different body positions was assessed. Thirteen patients undergoing liver resection were studied. Cardiac output (CO), mean arterial pressure (MAP) and CVP were measured. PVP and HVP were measured using tip manometer catheters at baseline (BL) in horizontal position; during NG infusion, targeting a MAP of 60 mmHg, with NG infusion and the patient placed in 10 head-down position. NG infusion reduced HVP from 9.7 ± 2.4 to 7.2 ± 2.4, PVP from 12.3 ± 2.2 to 9.7 ± 3.0 and CVP from 9.8 ± 1.9 to 7.2 ± 2.1 mmHg at BL. Head-down tilt during ongoing NG resulted in increases in HVP to 8.2 ± 2.1, PVP to 10.7 ± 3 and CVP to 11 ± 1.9 mmHg. CO at BL was 6.3 ± 1.1, which was reduced by NG to 5.8 ± 1.2. Head-down tilt together with NG infusion restored CO to 6.3 ± 1.0 l/min. NG infusion leads to parallel reductions in CVP, HVP and PVP at horizontal body position. Thus, CVP can be used to guide NG dosage and fluid administration at horizontal position. NG infusion can be used to reduce HVP. Head-down tilt can be used during NG infusion to improve both blood pressure and CO without substantial increase in liver venous pressure. In head-down tilt, CVP dissociates from HVP and PVP. © 2014 The Acta Anaesthesiologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.

Shellac Films as a Natural Dielectric Layer for Enhanced Electron Transport in Polymer Field-Effect Transistors.

Science.gov (United States)

Baek, Seung Woon; Ha, Jong-Woon; Yoon, Minho; Hwang, Do-Hoon; Lee, Jiyoul

2018-06-06

Shellac, a natural polymer resin obtained from the secretions of lac bugs, was evaluated as a dielectric layer in organic field-effect transistors (OFETs) on the basis of donor (D)-acceptor (A)-type conjugated semiconducting copolymers. The measured dielectric constant and breakdown field of the shellac layer were ∼3.4 and 3.0 MV/cm, respectively, comparable with those of a poly(4-vinylphenol) (PVP) film, a commonly used dielectric material. Bottom-gate/top-contact OFETs were fabricated with shellac or PVP as the dielectric layer and one of three different D-A-type semiconducting copolymers as the active layer: poly(cyclopentadithiophene- alt-benzothiadiazole) with p-type characteristics, poly(naphthalene-bis(dicarboximide)- alt-bithiophene) [P(NDI2OD-T2)] with n-type characteristics, and poly(dithienyl-diketopyrrolopyrrole- alt-thienothiophene) [P(DPP2T-TT)] with ambipolar characteristics. The electrical characteristics of the fabricated OFETs were then measured. For all active layers, OFETs with a shellac film as the dielectric layer exhibited a better mobility than those with PVP. For example, the mobility of the OFET with a shellac dielectric and n-type P(NDI2OD-T2) active layer was approximately 2 orders of magnitude greater than that of the corresponding OFET with a PVP insulating layer. When P(DPP2T-TT) served as the active layer, the OFET with shellac as the dielectric exhibited ambipolar characteristics, whereas the corresponding OFET with the PVP dielectric operated only in hole-accumulation mode. The total density of states was analyzed using technology computer-aided design simulations. The results revealed that compared with the OFETs with PVP as the dielectric, the OFETs with shellac as the dielectric had a lower trap-site density at the polymer semiconductor/dielectric interface and much fewer acceptor-like trap sites acting as electron traps. These results demonstrate that shellac is a suitable dielectric material for D-A-type semiconducting

Factors Affecting the Improvement of the Initial Peak Urinary Flow Rate after Transurethral Resection of the Prostate or Photoselective Vaporization of the Prostate for Treating Benign Prostatic Hyperplasia

Directory of Open Access Journals (Sweden)

Hwa Sub Choi

2011-03-01

Full Text Available Purpose We evaluated the factors that affect the improvement of the initial peak flow rate after transurethral resection of the prostate (TURP or photoselective vaporization of the prostate (PVP for benign prostatic hyperplasia (BPH patients by using noninvasive tools. Methods One hundred and twenty seven BPH patients who had undergone TURP or PVP between January 2005 and May 2009 were evaluated. They were divided into 2 groups: the postoperative initial peak urinary flow rate (Qmax was less than 10 mL/sec (Group 1; n=37, TURP=11, PVP=26 and more than 10 mL/sec (Group 2; n=90, TURP=41, PVP=49. We confirmed the patients' preoperative check lists. The check list were the international prostate symptom score (IPSS, the quality of life score, a past history of acute urinary retention (AUR, body mass index and/or pyuria, the serum prostate-specific antigen (PSA level and the prostate volume, the prostate transitional zone volume and prostatic calcification. The initial Qmax was measured at the outpatient clinic one week after discharge. Results The improvement rate was not significant difference between the TURP group (78.8% and the PVP group (65.3%. The efficacy parameters were the IPSS-storage symptom score, the prostate volume, the PSA level and a past history of AUR. The IPSS-storage symptom scores of Group 1 (12.3±3.3 was higher than those of Group 2 (10.5±1.7. The prostate volume of Group 2 (42.3±16.6 g was bigger than that of Group 1 (36.6±7.8 g. The PSA level of Group 2 (3.8±2.6 ng/mL was higher than that of Group 1 (2.6±2.6 ng/mL. A past history of AUR in Group 1 (35.1% was more prevalent than that of Group 2 (15.6%. Conclusions The non-invasive factors affecting the initial Qmax after TURP or PVP were the IPSS-storage symptom score, the prostate volume and a past history of AUR. Accordingly, in patients who have a higher IPSS-storage symptom score, a smaller prostate volume and a history of AUR, there might be a detrimental effect on

Modulating the Optoelectronic Properties of Silver Nanowires Films: Effect of Capping Agent and Deposition Technique.

Science.gov (United States)

Lopez-Diaz, D; Merino, C; Velázquez, M M

2015-11-11

Silver nanowires 90 nm in diameter and 9 µm in length have been synthesized using different capping agents: polyvinyl pyrrolidone (PVP) and alkyl thiol of different chain lengths. The nanowire structure is not influenced by the displacement of PVP by alkyl thiols, although alkyl thiols modify the lateral aggregation of nanowires. We examined the effect of the capping agent and the deposition method on the optical and electrical properties of films prepared by Spray and the Langmuir-Schaefer methodologies. Our results revealed that nanowires capped with PVP and C8-thiol present the best optoelectronic properties. By using different deposition techniques and by modifying the nanowire surface density, we can modulate the optoelectronic properties of films. This strategy allows obtaining films with the optoelectronic properties required to manufacture touch screens and electromagnetic shielding.

Port Hope and area property value protection program: creating stability in the marketplace

International Nuclear Information System (INIS)

Gerestein, B.; Flynn, B.

2006-01-01

The Property Value Protection (PVP) Program, administered by the Low-Level Radioactive Waste Management Office (LLRWMO), functions as an integral part of the Port Hope Area Initiative, a $260M, 10-year project to clean up and safely manage low- level radioactive waste for the long-term in the Port Hope area. The PVP Program was established in March 2001 to compensate owners of residential, commercial or industrial properties in designated parts of the municipalities of Port Hope and Clarington. Compensation is awarded to owners if they realize financial loss on the sale or rental of their property or mortgage renewal difficulties as a result of the Initiative. Key features of the PVP Program include a claim process, an appeal process and the appointment of independent Compensation Officers to hear appeals. (author)

Percutaneous vertebroplasty for malignant fractures of the spine

International Nuclear Information System (INIS)

Kobayashi, Nobuo; Numaguchi, Yuji; Saida, Yukihisa

2011-01-01

To maintain the patient's quality of life, palliative treatment for symptomatic bone metastases is as important as treatment of the primary lesion. Percutaneous vertebroplasty (PVP) was initially reported as a minimally invasive treatment for painful vertebral angioma, and then began to be performed for not only vertebral metastases or multiple myeloma but also osteoporotic vertebral fractures. PVP has been widely performed for relieving pain and stabilizing vertebral bodies following compression fractures of osteoporotic vertebral bodies refractory to medical therapy. Brace treatment and open surgical intervention are less desirable in this population because of the associated medical comorbidities. The indication for this procedure was subsequently extended to the treatment of vertebral compression fractures related to osteoporosis, metastases, or multiple myeloma, with the analgesic and stabilizing effects on the spine being validated by multiple studies. PVP is now widely used as standard treatment for osteoporotic fractures and metastatic tumors of the vertebral bodies in the United States and Europe. The PVP procedure is performed using a biplane angiography unit under local anesthesia and conscious sedation in a conventional manner. The patient is placed in a prone position under sterile conditions. After a small skin incision is made, a disposable 11- or 13-gauge bone biopsy needle is positioned with its tip near the center of the pedicle. Anteroposterior and lateral fluoroscopy is used to guide the advancing needle through the pedicle into the vertebral body. Bone cement is prepared by combining sterile barium and polymethylmethacrylate (PMMA). Injection of bone cement is performed either manually or with an injection device. The effectiveness of percutaneous injection of PMMA for metastatic tumors in a weight-bearing region such as vertebral bodies and pelvis has been reported. Percutaneous injection of bone cement is a promising alternative therapy for

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

OpenAIRE

Masala, Salvatore; Calabria, Eros; Nezzo, Marco; 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 vertebra...

The efficiency of conventional microscopic selection is comparable to the hyaluronic acid binding method in selecting spermatozoa for male infertility patients.

Science.gov (United States)

Huang, Meng-Ting; Kuo-Kuang Lee, Robert; Lu, Chung-Hao; Chen, Ying-Jie; Li, Sheng-Hsiang; Hwu, Yuh-Ming

2015-02-01

To evaluate if hyaluronic acid (HA)-bound spermatozoa surpassed conventional microscopy-selected spermatozoa in the status of sperm DNA integrity by acridine orange (AO) fluorescence staining. Spermatozoa obtained from couples with indication for the intracytoplasmic sperm injection (ICSI) procedure due to male infertility (n = 34) and control males with normal sperm parameters (n = 12) were analyzed using AO fluorescence staining after density-gradient centrifugation (DGC), polyvinylpyrrolidone (PVP)-microscopic selection, and HA-binding selection to determine sperm DNA integrity. Percentages of DNA intact spermatozoa with green fluorescence were significantly higher in both PVP-microscopic selected spermatozoa (82.1 ± 24.0%) and HA-bound spermatozoa (83.9 ± 21.1%) than in spermatozoa prepared by DGC (66.8 ± 24.0%). However, there was no significant difference between the PVP-sperm and HA-sperm groups. When the percentage of green fluorescent spermatozoa prepared by DGC fell initially below 68%, both PVP-microscopic and HA-binding selection failed to select over 90% spermatozoa with intact DNA for ICSI in the male infertility group. Compared to control males with normal sperm parameters (99.3 ± 1.8%), the proportion of green fluorescence sperm after HA-binding selection from couples with male infertility (83.9 ± 21.1%) did not reach the range of > 99% reported by Yagci et al. The percentages of DNA intact spermatozoa between the PVP-sperm and HA-sperm groups were not significantly different. In an ICSI procedure, a well-trained embryologist will have the same ability to choose sperm with intact DNA by conventional microscopic selection as with HA-bound spermatozoa selection. Copyright © 2014. Published by Elsevier B.V.

Radiation Induced Polyvinylpyrrolidone/Polyacrylic Acid Nano-Gel Formation for Biomedical Applications

International Nuclear Information System (INIS)

AbdEl-Rehim, H.; Hegazy, E.A.; Eid, A.; Amr; Ali, A.

2010-01-01

Adopting polyvinylpyrrolidone as template macromolecules and acrylic acid (AA) as monomers, at a concentration ranged from .05 to 1.5%, pH sensitive nano-particle colloids were successfully prepared via template polymerization using gamma radiation in which polymerization of the monomer and self-assembly between the polymer and the template take place simultaneously. The self-assembly was driven by specific interactions between PVP and PAA produced in-situ, leading to PVP/PAAc nano-particles with insoluble inter-polymer complexes. Dynamic light scattering technique was used to indicate size shrinkage and surface charge increase of the PVP/PAAc nano-particles. Many factors affecting the PVP/PAAc nano-particle size such as irradiation dose rate, exposure dose, irradiation temperature and atmosphere, PVP MWt, and feed composition and concentration were investigated. It was found that the reactant feed composition and irradiation temperatures have a great influence on particle size of the prepared nanogel. The structure and morphology of the nano-particles were characterized by FT-IR, UV, viscometry and AFM methods. The structure stability of the nano-particles was studied at different pH solutions. The nano-particles exhibit excellent pH response. When pH changed from acid to base, the particles‘ volume expanded 100 times depending on the irradiation dose at which the nanogel was prepared. The prepared nanogel was loaded with flutamide anticancer drug in the presence of ethanol-water mixture solution and the amount of loaded flutamide was determined. The prepared nano scale polyvinylpyrrolidone/polyacrylic acid bio-polymeric system loaded with flutamide drug is being investigated as anticancer target drug. Also this system will be tested for the treatment of dry-eye-syndrome. (author)

New insights into the effects of biomaterial chemistry and topography on the morphology of kidney epithelial cells.

Science.gov (United States)

Hulshof, Frits; Schophuizen, Carolien; Mihajlovic, Milos; van Blitterswijk, Clemens; Masereeuw, Rosalinde; de Boer, Jan; Stamatialis, Dimitrios

2018-02-01

Increasing incidence of renal pathology in the western world calls for innovative research for the development of cell-based therapies such as a bioartificial kidney (BAK) device. To fulfil the multitude of kidney functions, the core component of the BAK is a living membrane consisting of a tight kidney cell monolayer with preserved functional organic ion transporters cultured on a polymeric membrane surface. This membrane, on one side, is in contact with blood and therefore should have excellent blood compatibility, whereas the other side should facilitate functional monolayer formation. This work investigated the effect of membrane chemistry and surface topography on kidney epithelial cells to improve the formation of a functional monolayer. To achieve this, microtopographies were fabricated with high resolution and reproducibility on polystyrene films and on polyethersulfone-polyvinyl pyrrolidone (PES-PVP) porous membranes. A conditionally immortalized proximal tubule epithelial cell line (ciPTEC) was cultured on both, and subsequently, the cell morphology and monolayer formation were assessed. Our results showed that L-dopamine coating of the PES-PVP was sufficient to support ciPTEC monolayer formation. The polystyrene topographies with large features were able to align the cells in various patterns without significantly disruption of monolayer formation; however, the PES-PVP topographies with large features disrupted the monolayer. In contrast, the PES-PVP membranes with small features and with large spacing supported well the ciPTEC monolayer formation. In addition, the topographical PES-PVP membranes were compatible as a substrate membrane to measure organic cation transporter activity in Transwell® systems. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

Research and development of radiation processing of polysaccharide in Indonesia

International Nuclear Information System (INIS)

Rekso, Gatot Trimulyadi

2007-01-01

The research activities on natural polymer in Indonesia, especially chitosan as growth promoters and carrageenan for hydrogel are summarized. Isolation processes of chitin from shrimp shell were developed and the technology was transferred to fishing villages in north and south seaside Java Island. Chitosan with 80.5% degree of deacetylation was irradiated in dry solid, wet and aqueous solution at a dose of 50 kGy by gamma ray from Co-60 source. Irradiation of chitosan in aqueous solution gives the highest decreasing of molecule weight from 1.6 x 10 4 become 1.1 x 10 4 . A large field experiment was carried out at a field of red chili in cooperation with farmer in the village. The irradiated chitosan were dissolved in water and 300 mL of water that contains concentration of 50 ppm chitosan was sprayed to red chili plant three times a week for each plant. Irradiation of chitosan in dry solid condition gives the highest degree of height growth of plant to 50.2% and the degree of growth promotion to 92.6%. The production yield was around 60% higher than without using irradiated chitosan. Modification of kappa carrageenan (κC) has been carried out by radiation co-crosslinking with poly(N-vinylpyrrolidone) (PVP) to prepare a new material. Solution of κC was mixed with PVP solution at various concentrations. PVP-κC hydrogel was obtained by irradiation of the solution with electron beams. The best condition for co-crosslinking of κC with PVP was established. The PVP-κC hydrogel can be used as a matrix for immobilization of bioactive materials and wound dressing. (author)

Radiation Induced Polyvinylpyrrolidone/Polyacrylic Acid Nano-Gel Formation for Biomedical Applications

Energy Technology Data Exchange (ETDEWEB)

AbdEl-Rehim, H.; Hegazy, E. A.; Eid, A.; Amr,; Ali, A., E-mail: ha_rehim@hotmail.com [National Centre for Radiation Research, Research Centre (NCRRT), Atomic Energy Authority NCRRT, P.O.Box 29, Nasr City, Cairo (Egypt)

2010-07-01

Adopting polyvinylpyrrolidone as template macromolecules and acrylic acid (AA) as monomers, at a concentration ranged from .05 to 1.5%, pH sensitive nano-particle colloids were successfully prepared via template polymerization using gamma radiation in which polymerization of the monomer and self-assembly between the polymer and the template take place simultaneously. The self-assembly was driven by specific interactions between PVP and PAA produced in-situ, leading to PVP/PAAc nano-particles with insoluble inter-polymer complexes. Dynamic light scattering technique was used to indicate size shrinkage and surface charge increase of the PVP/PAAc nano-particles. Many factors affecting the PVP/PAAc nano-particle size such as irradiation dose rate, exposure dose, irradiation temperature and atmosphere, PVP MWt, and feed composition and concentration were investigated. It was found that the reactant feed composition and irradiation temperatures have a great influence on particle size of the prepared nanogel. The structure and morphology of the nano-particles were characterized by FT-IR, UV, viscometry and AFM methods. The structure stability of the nano-particles was studied at different pH solutions. The nano-particles exhibit excellent pH response. When pH changed from acid to base, the particles‘ volume expanded 100 times depending on the irradiation dose at which the nanogel was prepared. The prepared nanogel was loaded with flutamide anticancer drug in the presence of ethanol-water mixture solution and the amount of loaded flutamide was determined. The prepared nano scale polyvinylpyrrolidone/polyacrylic acid bio-polymeric system loaded with flutamide drug is being investigated as anticancer target drug. Also this system will be tested for the treatment of dry-eye-syndrome. (author)

Morphological evolution of carbon nanofibers encapsulating SnCo alloys and its effect on growth of the solid electrolyte interphase layer.

Science.gov (United States)

Shin, Jungwoo; Ryu, Won-Hee; Park, Kyu-Sung; Kim, Il-Doo

2013-08-27

Two distinctive one-dimensional (1-D) carbon nanofibers (CNFs) encapsulating irregularly and homogeneously segregated SnCo nanoparticles were synthesized via electrospinning of polyvinylpyrrolidone (PVP) and polyacrylonitrile (PAN) polymers containing Sn-Co acetate precursors and subsequent calcination in reducing atmosphere. CNFs synthesized with PVP, which undergoes structural degradation of the polymer during carbonization processes, exhibited irregular segregation of heterogeneous alloy particles composed of SnCo, Co3Sn2, and SnO with a size distribution of 30-100 nm. Large and exposed multiphase SnCo particles in PVP-driven amorphous CNFs (SnCo/PVP-CNFs) kept decomposing liquid electrolyte and were partly detached from CNFs during cycling, leading to a capacity fading at the earlier cycles. The closer study of solid electrolyte interphase (SEI) layers formed on the CNFs reveals that the gradual growth of fiber radius due to continuous increment of SEI layer thickness led to capacity fading. In contrast, SnCo particles in PAN-driven CNFs (SnCo/PAN-CNFs) showed dramatically reduced crystallite sizes (<10 nm) of single phase SnCo nanoparticles which were entirely embedded in dense, semicrystalline, and highly conducting 1-D carbon matrix. The growth of SEI layer was limited and saturated during cycling. As a result, SnCo/PAN-CNFs showed much improved cyclability (97.9% capacity retention) and lower SEI layer thickness (86 nm) after 100 cycles compared to SnCo/PVP-CNFs (capacity retention, 71.9%; SEI layer thickness, 593 nm). This work verifies that the thermal behavior of carbon precursor is highly responsible for the growth mechanism of SEI layer accompanied with particles detachment and cyclability of alloy particle embedded CNFs.

Layer-by-layer assembly of thin organic films on PTFE activated by cold atmospheric plasma

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Tóth András

2014-12-01

Full Text Available An air diffuse coplanar surface barrier discharge is used to activate the surface of polytetrafluoroethylene (PTFE samples, which are subsequently coated with polyvinylpyrrolidone (PVP and tannic acid (TAN single, bi- and multilayers, respectively, using the dip-coating method. The surfaces are characterized by X-ray Photoelectron Spectroscopy (XPS, Attenuated Total Reflection – Fourier Transform Infrared Spectroscopy (ATR-FTIR and Atomic Force Microscopy (AFM. The XPS measurements show that with plasma treatment the F/C atomic ratio in the PTFE surface decreases, due to the diminution of the concentration of CF2 moieties, and also oxygen incorporation through formation of new C–O, C=O and O=C–O bonds can be observed. In the case of coated samples, the new bonds indicated by XPS show the bonding between the organic layer and the surface, and thus the stability of layers, while the gradual decrease of the concentration of F atoms with the number of deposited layers proves the creation of PVP/TAN bi- and multi-layers. According to the ATR-FTIR spectra, in the case of PVP/TAN multilayer hydrogen bonding develops between the PVP and TAN, which assures the stability of the multilayer. The AFM lateral friction measurements show that the macromolecular layers homogeneously coat the plasma treated PTFE surface.

Triple-Component Drug-Loaded Nanocomposites Prepared Using a Modified Coaxial Electrospinning

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Wei Qian

2013-01-01

Full Text Available Triple-component nanocomposites for improved sustained drug release profiles are successfully fabricated through a modified coaxial electrospinning process, in which only organic solvent N,N-dimethylacetamide was used as sheath fluid. Using polyacrylonitrile (PAN as filament-forming matrix, ibuprofen (IBU as functional ingredient, and polyvinylpyrrolidone (PVP as the additional component, the IBU/PVP/PAN triple-component nanocomposites had uniform structure and an average diameter of 620±120 nm and 650±120 nm when the contents of PVP in the nanofibers were 10.5% and 22.7%, respectively. The optimal sheath-to-core flow rate ratio was 0.11 under a total sheath and core fluid flow rate of 1.0 mL/h. Compared with the IBU/PAN composite nanofibers, the triple-component composites could release 92.1% and 97.8% of the contained IBU, significantly larger than a value of 73.4% from the former. The inclusion of PVP in the IBU/PAN could effectively avoid the entrapment of IBU in the insoluble PAN molecules, facilitating the in vitro release of IBU. The modified coaxial process and the resulted multiple component nanocomposites would provide new way for developing novel drug sustained materials and transdermal drug delivery systems.

High-quality total RNA isolation from melon (Cucumis melo L. fruits rich in polysaccharides

Directory of Open Access Journals (Sweden)

Gabrielle Silveira de Campos

2017-08-01

Full Text Available Melon, a member of the family Cucurbitaceae, is the fourth most important fruit in the world market and, on a volume basis, is Brazil’s main fresh fruit export. Many molecular techniques used to understand the maturation of these fruits require high concentrations of highly purified RNA. However, melons are rich in polyphenolic compounds and polysaccharides, which interfere with RNA extraction. This study aimed to determine the most appropriate method for total RNA extraction from melon fruits. Six extraction buffers were tested: T1 guanidine thiocyanate/phenol/chloroform; T2 sodium azide/?-mercaptoethanol; T3 phenol/guanidine thiocyanate; T4 CTAB/PVP/?-mercaptoethanol; T5 SDS/sodium perchlorate/PVP/?-mercaptoethanol, and T6 sarkosyl/PVP/guanidine thiocyanate, using the AxyPrepTM Multisource Total RNA Miniprep Kit. The best method for extracting RNA from both mature and green fruit was based on the SDS/PVP/?-mercaptoethanol buffer, because it rapidly generated a high quality and quantity of material. In general, higher amounts of RNA were obtained from green than mature fruits, probably due to the lower concentration of polysaccharides and water. The purified material can be used as a template in molecular techniques, such as microarrays, RT-PCR, and in the construction of cDNA and RNA-seq data.

Relationship between Chinese adjective descriptors of personality and emotional symptoms in young Chinese patients with bipolar disorders.

Science.gov (United States)

Yu, Enyan; Li, Huihui; Fan, Hongying; Gao, Qianqian; Tan, Yunfei; Lou, Junyao; Zhang, Jie; Wang, Wei

2015-12-01

To investigate whether personality traits are related to emotional symptoms (mania, hypomania, and depression) in Chinese patients with bipolar disorders. Patients with bipolar I and II disorders, and healthy volunteers, were assessed using the Chinese Adjective Descriptors of Personality (CADP) questionnaire, Mood Disorder Questionnaire (MDQ), Hypomanic Checklist (HCL-32), and Plutchik-van Praag Depression Inventory (PVP). Seventy-three patients with bipolar I disorder, 35 with bipolar II disorder and 216 healthy controls were included. Bipolar I and II groups scored significantly higher on MDQ, HCL-32 and PVP scales than controls; the bipolar II group scored lower on the MDQ, but higher on the HCL-32 and PVP than bipolar I. In the bipolar I group, the CADP Intelligent trait (β, 0.25) predicted MDQ; Intelligent (β, -0.24), Agreeable (β, 0.22) and Emotional (β, 0.34) traits predicted PVP. In the bipolar II group, Intelligent (β, 0.22), Agreeable (β, -0.24) and Unsocial (β, 0.31) traits predicted MDQ; Intelligent (β, -0.20), Agreeable (β, -0.31) and Emotional (β, -0.26) traits predicted HCL-32. Four out of five Chinese personality traits were associated with emotional symptoms in patients with bipolar I or II disorder, but displayed different associations depending on disorder type. © The Author(s) 2015.

Enhancement patterns and pseudo-washout of hepatic haemangiomas on gadoxetate disodium-enhanced liver MRI

Energy Technology Data Exchange (ETDEWEB)

Kim, Bohyun [University of Ulsan College of Medicine, Asan Medical Center, Department of Radiology and Research Institute of Radiology, Seoul (Korea, Republic of); Ajou University School of Medicine, Department of Radiology, Suwon (Korea, Republic of); Byun, Jae Ho; Kim, Hyoung Jung; Won, Hyung Jin; Kim, So Yeon; Shin, Yong Moon; Kim, Pyo Nyun [University of Ulsan College of Medicine, Asan Medical Center, Department of Radiology and Research Institute of Radiology, Seoul (Korea, Republic of)

2016-01-15

To compare the enhancement patterns and prevalence of pseudo-washout between rapidly and slowly enhancing hepatic haemangiomas on gadoxetate disodium-enhanced MRI in patients with chronic liver disease (CLD) and healthy liver (HL). On gadoxetate disodium-enhanced MRI, the extent of intralesional arterial enhancement >50 % and ≤50 % of lesions was defined as rapid and slow enhancement, respectively. The enhancement patterns and presence of pseudo-washout during the portal venous phase (PVP) and transitional phase (TP) of 74 hepatic haemangiomas were retrospectively evaluated in the CLD and HL groups. Sequential changes of signal-to-noise ratio (SNR) were measured in unenhanced phase, PVP and TP. Irrespective of hepatic health status, pseudo-washout in TP was significantly more common in the rapidly enhancing haemangiomas (p ≤ 0.026). In both groups, rapidly enhancing haemangiomas showed complete or progressive incomplete enhancement in PVP, which either lasted or transformed to pseudo-washout in TP, whereas slowly enhancing haemangiomas showed progressive incomplete enhancement in PVP and TP. SNR of hepatic parenchyma continued to rise until TP, whereas that of portal vein and haemangioma falls in TP. Regardless of CLD, pseudo-washout in TP was more common in rapidly than in slowly enhancing haemangiomas, with enhancement patterns differing in the two subgroups. (orig.)

Tuning the thermal diffusivity of silver based nanofluids by controlling nanoparticle aggregation

International Nuclear Information System (INIS)

Agresti, Filippo; Barison, Simona; Battiston, Simone; Pagura, Cesare; Fabrizio, Monica; Colla, Laura; Fedele, Laura

2013-01-01

With the aim of preparing stable nanofluids for heat exchange applications and to study the effect of surfactant on the aggregation of nanoparticles and thermal diffusivity, stable silver colloids were synthesized in water by a green method, reducing AgNO 3 with fructose in the presence of poly-vinylpyrollidone (PVP) of various molecular weights. A silver nanopowder was precipitated from the colloids and re-dispersed at 4 vol% in deionized water. The Ag colloids were characterized by UV–visible spectroscopy, combined dynamic light scattering and ζ-potential measurements, and laser flash thermal diffusivity. The Ag nanopowders were characterized by scanning electron microscopy and thermal gravimetric analysis. It was found that the molecular weight of PVP strongly affects the ζ-potential and the aggregation of nanoparticles, thereby affecting the thermal diffusivity of the obtained colloids. In particular, it was observed that on increasing the molecular weight of PVP the absolute value of the ζ-potential is reduced, leading to increased aggregation of nanoparticles. A clear relation was identified between thermal diffusivity and aggregation, showing higher thermal diffusivity for nanofluids having higher aggregation. A maximum improvement of thermal diffusivity by about 12% was found for nanofluids prepared with PVP having higher molecular weight. (paper)

Enhancement patterns and pseudo-washout of hepatic haemangiomas on gadoxetate disodium-enhanced liver MRI

International Nuclear Information System (INIS)

Kim, Bohyun; Byun, Jae Ho; Kim, Hyoung Jung; Won, Hyung Jin; Kim, So Yeon; Shin, Yong Moon; Kim, Pyo Nyun

2016-01-01

To compare the enhancement patterns and prevalence of pseudo-washout between rapidly and slowly enhancing hepatic haemangiomas on gadoxetate disodium-enhanced MRI in patients with chronic liver disease (CLD) and healthy liver (HL). On gadoxetate disodium-enhanced MRI, the extent of intralesional arterial enhancement >50 % and ≤50 % of lesions was defined as rapid and slow enhancement, respectively. The enhancement patterns and presence of pseudo-washout during the portal venous phase (PVP) and transitional phase (TP) of 74 hepatic haemangiomas were retrospectively evaluated in the CLD and HL groups. Sequential changes of signal-to-noise ratio (SNR) were measured in unenhanced phase, PVP and TP. Irrespective of hepatic health status, pseudo-washout in TP was significantly more common in the rapidly enhancing haemangiomas (p ≤ 0.026). In both groups, rapidly enhancing haemangiomas showed complete or progressive incomplete enhancement in PVP, which either lasted or transformed to pseudo-washout in TP, whereas slowly enhancing haemangiomas showed progressive incomplete enhancement in PVP and TP. SNR of hepatic parenchyma continued to rise until TP, whereas that of portal vein and haemangioma falls in TP. Regardless of CLD, pseudo-washout in TP was more common in rapidly than in slowly enhancing haemangiomas, with enhancement patterns differing in the two subgroups. (orig.)

Analysis of a nanocrystalline polymer dispersion of ebselen using solid-state NMR, Raman microscopy, and powder X-ray diffraction.

Science.gov (United States)

Vogt, Frederick G; Williams, Glenn R

2012-07-01

Nanocrystalline drug-polymer dispersions are of significant interest in pharmaceutical delivery. The purpose of this work is to demonstrate the applicability of methods based on two-dimensional (2D) and multinuclear solid-state NMR (SSNMR) to a novel nanocrystalline pharmaceutical dispersion of ebselen with polyvinylpyrrolidone-vinyl acetate (PVP-VA), after initial characterization with other techniques. A nanocrystalline dispersion of ebselen with PVP-VA was prepared and characterized by powder X-ray diffraction (PXRD), confocal Raman microscopy and mapping, and differential scanning calorimetry (DSC), and then subjected to detailed 1D and 2D SSNMR analysis involving ¹H, ¹³C, and ⁷⁷Se isotopes and ¹H spin diffusion. PXRD was used to show that dispersion contains nanocrystalline ebselen in the 35-60 nm size range. Confocal Raman microscopy and spectral mapping were able to detect regions where short-range interactions may occur between ebselen and PVP-VA. Spin diffusion effects were analyzed using 2D SSNMR experiments and are able to directly detect interactions between ebselen and the surrounding PVP-VA. The methods used here, particularly the 2D SSNMR methods based on spin diffusion, provided detailed structural information about a nanocrystalline polymer dispersion of ebselen, and should be useful in other studies of these types of materials.

Oral fast-dissolving drug delivery membranes prepared from electrospun polyvinylpyrrolidone ultrafine fibers

International Nuclear Information System (INIS)

Yu Dengguang; Shen Xiaxia; Zhu Limin; Branford-White, Chris; White, Kenneth; Annie Bligh, S W

2009-01-01

Oral fast-dissolving drug delivery membranes (FDMs) for poorly water-soluble drugs were prepared via electrospinning technology with ibuprofen as the model drug and polyvinylpyrrolidone (PVP) K30 as the filament-forming polymer and drug carrier. Results from differential scanning calorimetry, x-ray diffraction, and morphological observations demonstrated that ibuprofen was distributed in the ultrafine fibers in the form of nanosolid dispersions and the physical status of drug was an amorphous or molecular form, different from that of the pure drug and a physical mixture of PVP and ibuprofen. Fourier-transform infrared spectroscopy results illustrated that the main interactions between PVP and ibuprofen were mediated through hydrogen bonding. Pharmacotechnical tests showed that FDMs with different drug contents had almost the same wetting and disintegrating times, about 15 and 8 s, respectively, but significantly different drug dissolution rates due to the different physical status of the drug and the different drug-release-controlled mechanisms. 84.9% and 58.7% of ibuprofen was released in the first 20 s for FDMs with a drug-to-PVP ratio of 1:4 and 1:2, respectively. Electrospun ultrafine fibers have the potential to be used as solid dispersions to improve the dissolution profiles of poorly water-soluble drugs or as oral fast disintegrating drug delivery systems.

Enhancing the bioavailability of magnolol in rabbits using melting solid dispersion with polyvinylpyrrolidone.

Science.gov (United States)

Lin, Shiuan-Pey; Hou, Yu-Chi; Liao, Tzu-Yun; Tsai, Shang-Yuan

2014-03-01

Preparation of magnolol-loaded amorphous solid dispersion was investigated for improving the bioavailability. A solid dispersion of magnolol was prepared with polyvinylpyrrolidone K-30 (PVP) by melting method, and the physical properties were characterized by using differential scanning calorimetry, powder X-ray diffractometry, Fourier transformation-infrared spectroscopy and scanning electron microscope. In addition, dissolution test was also performed. Subsequently, the bioavailability of magnolol pure compound, its physical mixture and solid dispersion were compared in rabbits. The blood samples withdrawn via marginal ear vein at specific time points were assayed by HPLC method. Oral administration of the solid dispersion of magnolol with PVP significantly increased the systemic exposures of magnolol and magnolol sulfates/glucuronides by 80.1% and 142.8%, respectively, compared to those given with magnolol pure compound. Magnolol-loaded amorphous solid dispersion with PVP has demonstrated enhanced bioavailability of magnolol in rabbits.

Influence of the electronic distribution of polymers in the spatial conformation of polymer grafted carbon nanotube composites

Energy Technology Data Exchange (ETDEWEB)

Garate, H. [Universidad de Buenos Aires, FCEyN, Depto. de Fisica IFIBA-CONICET LPyMC, Pabellon I, Buenos Aires 1428 (Argentina); Universidad de Buenos Aires, FCEyN, Depto. de Quimica Organica, (CIHIDECAR-CONICET) Buenos Aires 1428 (Argentina); De Falco, A. [Universidad de Buenos Aires, FCEyN, Depto. de Fisica IFIBA-CONICET LPyMC, Pabellon I, Buenos Aires 1428 (Argentina); Moreno, M.S. [Centro Atomico Bariloche, 8400 S.C. de Bariloche (Argentina); Fascio, M.L. [Universidad de Buenos Aires, FCEyN, Depto. de Quimica Organica, (CIHIDECAR-CONICET) Buenos Aires 1428 (Argentina); Goyanes, S. [Universidad de Buenos Aires, FCEyN, Depto. de Fisica IFIBA-CONICET LPyMC, Pabellon I, Buenos Aires 1428 (Argentina); Consejo Nacional de Investigaciones Cientificas y Tecnicas (CONICET) (Argentina); D' Accorso, N.B., E-mail: norma@qo.fcen.uba.ar [Universidad de Buenos Aires, FCEyN, Depto. de Quimica Organica, (CIHIDECAR-CONICET) Buenos Aires 1428 (Argentina); Consejo Nacional de Investigaciones Cientificas y Tecnicas (CONICET) (Argentina)

2012-08-15

In this work we report the covalent functionalization of multiwalled carbon nanotubes (MWCNTs) with polyacrylonitrile (PAN) and polyvinylpyridine (PVP) by the graft from method. Differences in the electronic distribution of both polymers resulted in different interaction between polymers and the nanotubes. It was found that PVP chains wrapped the nanotubes while nanotubes functionalized with PAN presented PAN chains forming amorphous entanglements on the nanoscale linked to the MWCNTs. Differences in the conformation between both polymers and the MWCNTs can be attributed to interactions between the aromatic groups in PVP and the MWCNTs through {pi}-{pi} stacking. The absence of aromatic groups in the case of the PAN chains favours the interaction between them. The functionalization efficiency was characterized using Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA) and UV-vis spectroscopy, while morphological changes were characterized by high resolution transmission electron microscopy.

Modulating the Optoelectronic Properties of Silver Nanowires Films: Effect of Capping Agent and Deposition Technique

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D. Lopez-Diaz

2015-11-01

Full Text Available Silver nanowires 90 nm in diameter and 9 µm in length have been synthesized using different capping agents: polyvinyl pyrrolidone (PVP and alkyl thiol of different chain lengths. The nanowire structure is not influenced by the displacement of PVP by alkyl thiols, although alkyl thiols modify the lateral aggregation of nanowires. We examined the effect of the capping agent and the deposition method on the optical and electrical properties of films prepared by Spray and the Langmuir-Schaefer methodologies. Our results revealed that nanowires capped with PVP and C8-thiol present the best optoelectronic properties. By using different deposition techniques and by modifying the nanowire surface density, we can modulate the optoelectronic properties of films. This strategy allows obtaining films with the optoelectronic properties required to manufacture touch screens and electromagnetic shielding.

An Alternative Synthesis Route of LiFePO4-Carbon Composites for Li-Ion Cathodes

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Yongbing Lou

2013-01-01

Full Text Available LiFePO4-Carbon (LFP/C composites with high purity and good crystallinity were prepared by an improved environmentally benign and low-cost solvothermal method. Capping agent polyvinylpyrrolidone (PVP and polyethylene glycol (PEG-400 showed no significant dispersive effect during the synthesis. These capping agents were converted into networking carbons after annealing, which consequently improved the charge and discharge performance. It was able to deliver a high initial discharge specific capacity of 154.1 mAh g−1 for sample prepared with PVP and 145.6 mAh g−1 for sample prepared with PEG-400 while having great capacity retention. The rate capability and cycling performance of LFP/C samples prepared with PVP or PEG-400 at high current rates were significantly improved compared to the LFP/C sample prepared without a capping agent.

Hydrogel wound dressing preparation at the laboratory scale by using electron beam and gamma radiation

International Nuclear Information System (INIS)

Rapado Raneque, Manuel; Rodriguez Rodriguez, Alejandro; Peniche Covas, Carlos

2013-01-01

The present work describes the preparation of hydrogel based on cross-linked networks of poly (N-vinylpirrolidone), PVP, with polyethyleneglicol and agar with 90% water and PVP nancomposites with a synthetic nanoclay, Laponite XLG, for use as burn dressings. These systems were obtained in two ways: using gamma Co-60 and electron beam radiation. The gelation obtained dose was D g = 1.72 kGy. The elastic modulus of hydrogel was independent of the method of irradiation. It was 0.39 MPa for the hydrogel irradiated with gamma Co-60 and 0.38 MPa for electron beam irradiation. The elastic modulus of the nanocomposite membrane was 1.25 MPa, three times higher. These results indicate that the PVP/Laponite XLG nanocomposite hydrogel membrane is the best choice for wound dressing applications due to its high water sorption capacity and its superior mechanical properties.

Evaluation of binding properties of Plantago psyllium seed mucilage.

Science.gov (United States)

Saeedi, Majid; Morteza-Semnani, Katayoun; Ansoroudi, Farshad; Fallah, Saeed; Amin, Gholamreza

2010-09-01

Mucilage extracted from Plantago psyllium seeds was evaluated for inertness and safety parameters. The suitability of psyllium mucilage for a pharmaceutical binder was assessed in paracetamol tablets. Properties of the granules prepared using different concentrations of psyllium mucilage was compared with PVP and tragacanth. Psyllium mucilage at 5 % (m/m) was found to be comparable with 3 % (m/m) of PVP. Investigated paracetamol tablets indicated that psyllium mucilage can retard the drug release.

Synthesis of Nano Hydroxyapatite by SDS-PVP Soft Template and Its Application as Medicine Delayed-Release Carrier%SDS-PVP模板体系中纳米羟基磷灰石的合成及其药物缓释载体性能

Institute of Scientific and Technical Information of China (English)

李玲; 杜鹏飞; 赵庆; 方云

2010-01-01

在室温下,采用十二烷基硫酸钠(SDS)-聚乙烯吡咯烷酮(PVP)二元体系为反应模板,合成得到了纳米羟基磷灰石(HAP).通过透射电镜、X射线衍射、红外光谱等方法对产品进行表征,结果表明:所得产品为六方晶系的纳米HAP,产品尺寸形貌均一,为50 nm×2 nm的针状结构.由于使用的模板生物安全性良好,所得纳米HAP尺寸又较小,因此本方法是制备生物医学工程领域所需纳米HAP的新方法.采用对乙酰氨基酚为药物负载对象的研究表明,纳米HAP负载药物后,经12 h药物释放率方达到94.4%,能够有效地起到药物缓释的作用.

Low molecular weight chitosan-coated silver nanoparticles are effective for the treatment of MRSA-infected wounds

Directory of Open Access Journals (Sweden)

Peng Y

2017-01-01

Full Text Available Yinbo Peng,1 Chenlu Song,1 Chuanfeng Yang,1 Qige Guo,1 Min Yao1,2 1Department of Burns and Plastic Surgery, Shanghai Ninth People’s Hospital, Institute of Traumatic Medicine, Shanghai Jiao Tong University School of Medicine, Shanghai, People’s Republic of China; 2Department of Dermatology, Wellman Center for Photomedicine, Harvard Medical School, Massachusetts General Hospital, Boston, MA, USA Abstract: Silver nanoparticles (AgNPs are being widely applied as topical wound materials; however, accumulated deposition of silver in the liver, spleen, and other main organs may lead to organ damage and dysfunction. We report here that low molecular weight chitosan-coated silver nanoparticles (LMWC-AgNPs are effective against methicillin-resistant Staphylococcus aureus (MRSA, have better biocompatibility, and have lower body absorption characteristics when compared with polyvinylpyrrolidone-coated silver nanoparticles (PVP-AgNPs and silver nanoparticles without surface stabilizer (uncoated-AgNPs in a dorsal MRSA wound infection mouse model. LMWC-AgNPs were synthesized by reducing silver nitrate with low molecular weight chitosan as a stabilizer and reducing agent, while PVP-AgNPs were synthesized using polyvinylpyrrolidone as a stabilizer and ethanol as a reducing agent. AgNPs with different surface stabilizers were identified by UV-visible absorption spectrometry, and particle size was determined by transmission electron microscopy. UV-visible absorption spectra of LMWC-AgNPs, PVP-AgNPs and uncoated-AgNPs were similar and their sizes were in the range of 10–30 nm. In vitro experiments showed that the three types of AgNPs had similar MRSA-killing effects, with obvious effect at 4 µg/mL and 100% effect at 8 µg/mL. Bacteriostatic annulus experiments also showed that all the three types of AgNPs had similar antibacterial inhibitory effect at 10 µg/mL. Cell counting kit-8 assay and Hoechst/propidium iodide (PI staining showed that LMWC-AgNPs were

Oxygen permeability of the pigmented material used in cosmetic daily disposable contact lenses.

Science.gov (United States)

Galas, Stephen; Copper, Lenora L

2016-01-01

To evaluate the individual contributions of pigment colorant and packing solution containing polyvinyl pyrrolidone (PVP) on the oxygen permeability (Dk) of a cosmetic printed etafilcon A daily disposable contact lens packaged with PVP. The oxygen transport of a contact lens is evaluated through the central optical zone of the lens. Cosmetic printed contact lenses contain pigment colorant in the periphery or mid-periphery of the lens. Therefore, to assess the impact of cosmetic print on oxygen permeability, special lenses need to be produced that contain the colorant within the central optical zone. This technique was used to obtain multiple measurements of nonedge-corrected Dk/t of both the center pigmented lens and its nonpigmented equivalent, using a polarographic measurement described in International Organization for Standardization (ISO) 18369-4:2006(E), and the Dk derived for each measurement is corrected for edge effect. In addition, the edge-corrected Dk values of lenses made from the same monomer batch were measured. The lenses were packaged and autoclaved with and without proprietary technology which embeds PVP in the contact lens during autoclaving. The resulting Dk value of the printed lens material was then used with thickness data to generate true Dk/t profiles for a given lens power. The edge-corrected Dk of the printed etafilcon A lens with offset pigment colorant was measured to be 19.7×10 -11 (cm 2 /s) (mL O 2 /mL·mmHg) at 35°C. This was within ±20% tolerance range as specified in ISO 18369-2:2012(E) for the edge-corrected Dk of the nonpigmented etafilcon A control lens evaluated during the same session, 19.5×10 -11 (cm 2 /s) (mL O 2 /mL·mmHg). The edge-corrected Dk values of the lenses packaged with PVP (mean 20.1, standard deviation [SD] 0.3) were also within the ±20% tolerance range compared to those packaged without PVP (mean 20.0, SD 0.3). The pigment colorant and PVP embedded in the contact lens during autoclaving were not found to

Analysis and simulation of water supply systems with photovoltaic pumping; Analise e simulacao de sistemas de abastecimento de agua com tecnologia fotovoltaica

Energy Technology Data Exchange (ETDEWEB)

Vilela, Olga de Castro

1996-09-01

During the last two decades, a remarkable progress on the technology of photovoltaic pumping systems (PVP) has been observed. The decrease in the costs of the photovoltaic module and the increase in the efficiency of photovoltaic pumping systems (generator and motor-pump) make PVP systems a good option for rural communities. Most analysis and simulations of PVP systems, utility function, assume the existence of a linear relationship between the hydraulic power and the solar collected radiation. Usually, more general relations exist between those variables. This work presents a new procedure for the analysis and simulation of PVP systems, which uses the utility function to consider the fluctuations in solar radiation, and leads to analytical solutions for PVP systems whose behavior can be represented by general functions, including linear relations as a particular case. The system analyzed considers the energy source (solar radiation) and the components of the water supply system like water source, photovoltaic array, subsystem for conversion of electric into hydraulic energy and, finally, hydraulic network. An analytical procedure to calculate absorbed solar radiation in the optical layers of the photovoltaic module was developed, substituting the conventional ray tracing method. The volume of pumped water was obtained integrating the water flow rate through time, considering the fluctuations related to the behavior of solar radiation and the minimum level of radiation necessary to produce useful energy. The mathematical properties of the utility function allow to derive analytical solutions for the integrals of water flow and hydraulic power. At the same time, we developed a spreadsheet which allows tho visualize the behavior of all variables involved in the process and offers the possibility of simulating different situations in order to maximize the amount of pumped water for any given system. The results obtained through the new procedure were compared with

Impact of surface coating and environmental conditions on the fate and transport of silver nanoparticles in the aquatic environment

Energy Technology Data Exchange (ETDEWEB)

Ellis, Laura-Jayne A.; Valsami-Jones, Eugenia [School of Geography, Earth and Environmental Sciences, University of Birmingham, Edgbaston, Birmingham B15 2TT (United Kingdom); Lead, Jamie R., E-mail: Jlead@mailbox.sc.edu [School of Geography, Earth and Environmental Sciences, University of Birmingham, Edgbaston, Birmingham B15 2TT (United Kingdom); Center for Environmental Nanoscience and Risk (CENR), Department of Environmental Health Sciences, Arnold School of Public Health, University of South Carolina, Columbia 29208 (United States); Baalousha, Mohammed, E-mail: Mbaalous@mailbox.sc.edu [Center for Environmental Nanoscience and Risk (CENR), Department of Environmental Health Sciences, Arnold School of Public Health, University of South Carolina, Columbia 29208 (United States)

2016-10-15

The role of surface coating (polyvinylpyrrolidone (PVP) and citrate) and water chemistry on the fate and behavior of AgNPs in aquatic microcosms is reported in this study. The migration and transformation of the AgNPs was examined in low (ultrapure water-UPW) and high ionic strength (moderately hard water – MHW) preparations, and in the presence of modeled natural organic matter (NOM) of Suwannee River Fulvic Acid (SRFA). The migration and fate of the AgNPs in the microcosms was validated using a sedimentation-diffusion model and the aggregation behavior was monitored by UV–visible spectrometry (UV–vis). Dissolved and particulate Ag concentrations (% Ag) were analyzed by ultrafiltration methods. Imaging of the AgNPs was captured using transmission electron microscopy (TEM). Results indicate that PVP-coated AgNPs (PVP-AgNPs) remained stable for 28 days with similarly distributed concentrations of the PVP-AgNPs throughout the columns in each of the water conditions after approximately 96 h (4 days). The sedimentation-diffusion model confirmed PVP-AgNP stability in each condition, by showing diffusion dominated transport by using the original unaltered AgNP sizes to fit the parameters. In comparison, citrate AgNPs were largely unstable in the more complex water preparations (MHW). In MHW, aggregation dominated behavior followed by sedimentation/dissolution controlled transport was observed. The addition of SRFA to MHW resulted in small stabilizing effects, to the citrate coated AgNPs, producing smaller sized AgNPs (TEM) and mixed sedimentation and diffusion migration compared the studies absent of SRFA. The results suggest that surface coating and solution chemistry has a major impact on AgNP stability, furthermore the corresponding modeling will support the experimental understanding of the overall fate of AgNPs in the environment. - Highlights: • Aquatic microcosms were used to study the transport and behavior of AgNPs • Experiments were conducted in low

Impact of surface coating and environmental conditions on the fate and transport of silver nanoparticles in the aquatic environment

International Nuclear Information System (INIS)

Ellis, Laura-Jayne A.; Valsami-Jones, Eugenia; Lead, Jamie R.; Baalousha, Mohammed

2016-01-01

The role of surface coating (polyvinylpyrrolidone (PVP) and citrate) and water chemistry on the fate and behavior of AgNPs in aquatic microcosms is reported in this study. The migration and transformation of the AgNPs was examined in low (ultrapure water-UPW) and high ionic strength (moderately hard water – MHW) preparations, and in the presence of modeled natural organic matter (NOM) of Suwannee River Fulvic Acid (SRFA). The migration and fate of the AgNPs in the microcosms was validated using a sedimentation-diffusion model and the aggregation behavior was monitored by UV–visible spectrometry (UV–vis). Dissolved and particulate Ag concentrations (% Ag) were analyzed by ultrafiltration methods. Imaging of the AgNPs was captured using transmission electron microscopy (TEM). Results indicate that PVP-coated AgNPs (PVP-AgNPs) remained stable for 28 days with similarly distributed concentrations of the PVP-AgNPs throughout the columns in each of the water conditions after approximately 96 h (4 days). The sedimentation-diffusion model confirmed PVP-AgNP stability in each condition, by showing diffusion dominated transport by using the original unaltered AgNP sizes to fit the parameters. In comparison, citrate AgNPs were largely unstable in the more complex water preparations (MHW). In MHW, aggregation dominated behavior followed by sedimentation/dissolution controlled transport was observed. The addition of SRFA to MHW resulted in small stabilizing effects, to the citrate coated AgNPs, producing smaller sized AgNPs (TEM) and mixed sedimentation and diffusion migration compared the studies absent of SRFA. The results suggest that surface coating and solution chemistry has a major impact on AgNP stability, furthermore the corresponding modeling will support the experimental understanding of the overall fate of AgNPs in the environment. - Highlights: • Aquatic microcosms were used to study the transport and behavior of AgNPs • Experiments were conducted in low

CORROSION INHIBITION OF ALUMINUM ALLOY 3SR IN HCl BY POLYVINYLPYRROLIDONE AND POLYACRYLAMIDE: EFFECT OF MOLECULAR STRUCTURE ON INHIBITION EFFICIENCY

OpenAIRE

S. A. UMOREN

2009-01-01

The inhibitive performance of two water soluble polymers–polyacrylamide (PA) and polyvinylpyrrolidone (PVP) on the corrosion behavior of aluminum alloy 3SR in HCl solution was investigated using weight loss, hydrogen evolution, and thermometric methods at 30–60°C. Results obtained indicate that both polymers inhibited acid-induced corrosion of aluminum at the temperatures studied. PVP was found to be a better corrosion inhibitor than PA. All measurements from the three techniques show that in...

Replacement of Poly(vinyl pyrrolidone) by Thiols: A Systematic Study of Ag Nanocube Functionalization by Surface-Enhanced Raman Scattering

OpenAIRE

Moran, Christine H.; Rycenga, Matthew; Zhang, Qiang; Xia, Younan

2011-01-01

In this work, we used surface-enhanced Raman scattering (SERS) to monitor the replacement of poly(vinyl pyrrolidone) (PVP) on Ag nanocubes by cysteamine, thiol-terminated PEG, and benzenedithiol. PVP is widely used as a colloidal stabilizer and capping agent to control the shape of Ag (as well as many other noble metals) nanocrystals during synthesis, and to stabilize the final colloidal suspension. However, the surface chemistry of Ag nanocrystals often needs to be tailored for specific appl...

Improved Dielectric Properties of Polyvinylidene Fluoride Nanocomposite Embedded with Poly(vinylpyrrolidone)-Coated Gold Nanoparticles

KAUST Repository

Toor, Anju

2017-01-25

A novel nanocomposite dielectric was developed by embedding polyvinylpyrrolidone (PVP)-encapsulated gold (Au) nanoparticles in the polyvinylidene fluoride (PVDF) polymer matrix. The surface functionalization of Au nanoparticles with PVP facilitates favorable interaction between the particle and polymer phase, enhancing nanoparticle dispersion. To study the effect of entropic interactions on particle dispersion, nanocomposites with two different particle sizes (5 and 20 nm in diameter) were synthesized and characterized. A uniform particle distribution was observed for nanocomposite films consisting of 5 nm Au particles, in contrast to the film with 20 nm particles. The frequency-dependent dielectric permittivity and the loss tangent were studied for the nanocomposite films. These results showed the effectiveness of PVP ligand in controlling the agglomeration of Au particles in the PVDF matrix. Moreover, the study showed the effect of particle concentration on their spatial distribution in the polymer matrix and the dielectric properties of nanocomposite films.

Silver micro- and nano-particles obtained using different glycols as reducing agents and measurement of their conductivity

Directory of Open Access Journals (Sweden)

Moudir Naïma

2016-01-01

Full Text Available Synthesis of silver micro- and nano-particles for the preparation of conductive pastes for the metallization of solar cells was realized by chemical reduction in the presence and absence of poly(vinyl-pyrrolidone (PVP. Silver nitrate was used as a precursor in the presence of three polyols (ethylene glycol, di-ethylene glycol and propylene glycol tested at experimental temperatures near their boiling points. Six samples were obtained by this protocol. Three silver powders obtained without the use of PVP have a metallic luster appearance; however, the samples produced using an excess of PVP are in the form of stable colloidal dispersions of silver nano-particles. Structural characterizations of samples using a scanning electron microscope and X-ray diffractometer show a good crystallinity and spherical morphology. From DSC and TGA analyses, it was noticed that all the nano-silvers present in the colloidal suspension have the same thermal behavior.

Improved Dielectric Properties of Polyvinylidene Fluoride Nanocomposite Embedded with Poly(vinylpyrrolidone)-Coated Gold Nanoparticles

KAUST Repository

Toor, Anju; So, Hongyun; Pisano, Albert P.

2017-01-01

A novel nanocomposite dielectric was developed by embedding polyvinylpyrrolidone (PVP)-encapsulated gold (Au) nanoparticles in the polyvinylidene fluoride (PVDF) polymer matrix. The surface functionalization of Au nanoparticles with PVP facilitates favorable interaction between the particle and polymer phase, enhancing nanoparticle dispersion. To study the effect of entropic interactions on particle dispersion, nanocomposites with two different particle sizes (5 and 20 nm in diameter) were synthesized and characterized. A uniform particle distribution was observed for nanocomposite films consisting of 5 nm Au particles, in contrast to the film with 20 nm particles. The frequency-dependent dielectric permittivity and the loss tangent were studied for the nanocomposite films. These results showed the effectiveness of PVP ligand in controlling the agglomeration of Au particles in the PVDF matrix. Moreover, the study showed the effect of particle concentration on their spatial distribution in the polymer matrix and the dielectric properties of nanocomposite films.

Growth mechanism of silver nanowires synthesized by polyvinylpyrrolidone-assisted polyol reduction

International Nuclear Information System (INIS)

Gao Yan; Jiang Peng; Song Li; Liu Lifeng; Yan Xiaoqin; Zhou Zhenping; Liu Dongfang; Wang Jianxiong; Yuan Huajun; Zhang Zengxing; Zhao Xiaowei; Dou Xinyuan; Zhou Weiya; Wang Gang; Xie Sishen

2005-01-01

Silver (Ag) nanowires with a pentagonal cross section have been synthesized by polyvinylpyrrolidone (PVP)-assisted polyol reduction in the presence of Pt nanoparticle seeds. The UV-visible absorption spectra and scanning electron microscopy have been used to trace the growth process of the Ag nanowires. X-ray photoelectron spectroscopy investigation further shows that the PVP molecules are adsorbed on the surface of the Ag nanowires through Ag : O coordination. Comparing with the growth process of Ag nanoparticles, a possible growth mechanism of the Ag nanowires has been proposed. It is implied that the PVP molecules are used as both a protecting agent and a structure-directing agent for the growth of Ag nanowires. It is concluded that the five-fold twinning Ag nanoparticles are formed through heterogenous nucleation after the introduction of Pt nanoparticle seeds and then grow anisotropically along the (110) direction, while the growth along (100) is relatively depressed

Reusability Performance of Zinc Oxide Nanoparticles for Photocatalytic Degradation of POME

Science.gov (United States)

Zarifah Zainuri, Nur; Hanis Hayati Hairom, Nur; Abu Bakar Sidik, Dilaelyana; Misdan, Nurasyikin; Yusof, Norhaniza; Wahab Mohammad, Abdul

2018-03-01

Performance and reusability of different zinc oxide nanoparticles (ZnO-PVP and ZnO-PEG) for photocatalytic degradation of palm-mill oil effluent (POME) has been studied. The nanoparticles properties were characterised with fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and transmission electron microscopy (TEM). The TEM results show that ZnO-PEG nanoparticles exhibit the smaller size than ZnO-PVP with less agglomeration. It was found that ZnO-PEG shows better effectiveness than ZnO-PVP in reducing turbidity, colour and increasing the dissolved oxygen (DO). By using two types of reusability methods: (a) oven drying (b) hot water rinsing, the oven drying method portrayed the most efficient route for POME treatment. This research would be a solution to the palm oil industry for photocatalyst recovering as well as reduction of the chemical usage in order to meet the development of advanced and greener technologies.

Improving the Efficiency of Organic Solar Cells upon Addition of Polyvinylpyridine

Directory of Open Access Journals (Sweden)

Rita Rodrigues

2014-12-01

Full Text Available We report on the efficiency improvement of organic solar cells (OPVs based on the low energy gap polyfluorene derivative, APFO-3, and the soluble C60 fullerene PCBM, upon addition of a residual amount of poly (4-vinylpyridine (PVP. We find that the addition of 1% by weight of PVP with respect to the APFO-3 content leads to an increase of efficiency from 2.4% to 2.9%. Modifications in the phase separation details of the active layer were investigated as a possible origin of the efficiency increase. At high concentrations of PVP, the blend morphology is radically altered as observed by Atomic Force Microscopy. Although the use of low molecular weight additives is a routine method to improve OPVs efficiency, this report shows that inert polymers, in terms of optical and charge transport properties, may also improve the performance of polymer-based solar cells.

Improved galvanic replacement growth of Ag microstructures on Cu micro-grid for enhanced SERS detection of organic molecules

Energy Technology Data Exchange (ETDEWEB)

Guo, Tian-Long [Key Laboratory for Anisotropy and Texture of Materials, School of Materials and Metallurgy, Northeastern University, Shenyang 110819 (China); Advanced Materials Processing Unit, National Institute for Materials Science, Namiki 1–1, Tsukuba, Ibaraki 305-0044 (Japan); Li, Ji-Guang, E-mail: LI.Jiguang@nims.go.jp [Key Laboratory for Anisotropy and Texture of Materials, School of Materials and Metallurgy, Northeastern University, Shenyang 110819 (China); Advanced Materials Processing Unit, National Institute for Materials Science, Namiki 1–1, Tsukuba, Ibaraki 305-0044 (Japan); Sun, Xudong, E-mail: xdsun@mail.neu.edu.cn [Key Laboratory for Anisotropy and Texture of Materials, School of Materials and Metallurgy, Northeastern University, Shenyang 110819 (China); Sakka, Yoshio [Advanced Materials Processing Unit, National Institute for Materials Science, Namiki 1–1, Tsukuba, Ibaraki 305-0044 (Japan)

2016-04-01

Galvanic growth of Ag nano/micro-structures on Cu micro-grid was systematically studied for surface-enhanced Raman scattering (SERS) applications. Detailed characterizations via FE-SEM and HR-TEM showed that processing parameters, (reaction time, Ag{sup +} concentration, and PVP addition) all substantially affect thermodynamics/kinetics of the replacement reaction to yield substrates of significantly different microstructures/homogeneities and thus varied SERS performances (sensitivity, enhancement factor, and reproducibility) of the Ag substrates in the detection of R6G analyte. PVP as an additive was shown to notably alter nucleation/growth behaviors of the Ag crystals and promote the deposition of dense and uniform Ag films of nearly monodisperse polyhedrons/nanoplates through suppressing dendrites crystallization. Under optimized synthesis (50 mM of Ag{sup +}, 30 s of reaction, and 700 wt.% of PVP), Ag substrates exhibiting a high Raman signal enhancement factor of ~ 1.1 × 10{sup 6} and a low relative standard deviation of ~ 0.13 in the repeated detection of 10 μM R6G were obtained. The facile deposition and excellent performance reported in this work may allow the Ag microstructures to find wider SERS applications. Moreover, growth mechanisms of the different Ag nano/micro-structures were discussed based on extensive FE-SEM and HR-TEM analysis. - Highlights: • A facile synthetic technique of growing SERS active Ag substrates onto Cu micro-grid has been systematically studied. • Changing processing parameters has yielded Ag crystals of various morphologies and SERS performances. • PVP additive was observed to suppress Ag dendrite crystallization for nearly monodispersed Ag polyhedrons/nanoplates. • PVP modified SERS substrate exhibits excellent EF and RSD values in the repeated detection of 10 μM R6G analyte.

Asymmetric flow field-flow fractionation of manufactured silver nanoparticles spiked into soil solution.

Science.gov (United States)

Koopmans, G F; Hiemstra, T; Regelink, I C; Molleman, B; Comans, R N J

2015-05-01

Manufactured metallic silver nanoparticles (AgNP) are intensively utilized in consumer products and this will inevitably lead to their release to soils. To assess the environmental risks of AgNP in soils, quantification of both their concentration and size in soil solution is essential. We developed a methodology consisting of asymmetric flow field-flow fractionation (AF4) in combination with on-line detection by UV-vis spectroscopy and off-line HR-ICP-MS measurements to quantify the concentration and size of AgNP, coated with either citrate or polyvinylpyrrolidone (PVP), in water extracts of three different soils. The type of mobile phase was a critical factor in the fractionation of AgNP by AF4. In synthetic systems, fractionation of a series of virgin citrate- and PVP-coated AgNP (10-90 nm) with reasonably high recoveries could only be achieved with ultrahigh purity water as a mobile phase. For the soil water extracts, 0.01% (w:v) sodium dodecyl sulfate (SDS) at pH 8 was the key to a successful fractionation of the AgNP. With SDS, the primary size of AgNP in all soil water extracts could be determined by AF4, except for PVP-coated AgNP when clay colloids were present. The PVP-coated AgNP interacted with colloidal clay minerals, leading to an overestimation of their primary size. Similar interactions between PVP-coated AgNP and clay colloids can take place in the environment and facilitate their transport in soils, aquifers, and surface waters. In conclusion, AF4 in combination with UV-vis spectroscopy and HR-ICP-MS measurements is a powerful tool to characterize AgNP in soil solution if the appropriate mobile phase is used. Copyright © 2015 Elsevier B.V. All rights reserved.

Cocaine-like discriminative stimulus effects of alpha-pyrrolidinovalerophenone, methcathinone and their 3,4-methylenedioxy or 4-methyl analogs in rhesus monkeys.

Science.gov (United States)

Smith, Douglas A; Negus, S Stevens; Poklis, Justin L; Blough, Bruce E; Banks, Matthew L

2017-09-01

Synthetic cathinones are beta-ketone amphetamine analogs that have emerged as a heterogeneous class of abused compounds that function as either monoamine transporter substrates or inhibitors. Pre-clinical drug discrimination procedures are useful for interrogating structure-activity relationships of abuse-related drug effects; however, in vivo structure-activity relationship comparisons between synthetic cathinones with different mechanisms of action are lacking. The aim of the present study was to determine whether the cocaine-like discriminative stimulus effects of the monoamine transporter inhibitor alpha-pyrrolidinovalerophenone (alpha-PVP) and the monoamine transporter substrate methcathinone were differentially sensitive to 3,4-methylenedioxy and 4-methyl substitutions. Male rhesus monkeys (n = 4) were trained to discriminate intramuscular cocaine (0.32 mg/kg) from saline in a two-key food-reinforced discrimination procedure. Potency and timecourse of cocaine-like discriminative stimulus effects were determined for (±)-alpha-PVP, (±)-methcathinone and their 3,4-methylenedioxy or 4-methyl analogs. Alpha-PVP and methcathinone produced dose- and time-dependent cocaine-like effects. A 3,4-methylenedioxy addition to either alpha-PVP or methcathinone (methylone) did not alter the potency or efficacy to produce cocaine-like effects, but did prolong the time course. A 4-methyl addition to alpha-PVP (pyrovalerone) did not alter the potency or efficacy to produce cocaine-like effects, but did prolong the time course. In contrast, addition of a 4-methyl moiety to methcathinone (4MMC; mephedrone) significantly attenuated efficacy to produce cocaine-like effects. Overall, these results suggest different structural requirements for cocaine-like discriminative stimulus effects of monoamine transporter inhibitor and substrate synthetic cathinone analogs. Given that 4MMC is more hydrophobic than MDMC, these results suggest that hydrophobicity may be an important

Electrospun curcumin-loaded cellulose acetate/polyvinylpyrrolidone fibrous materials with complex architecture and antibacterial activity

International Nuclear Information System (INIS)

Tsekova, Petya B.; Spasova, Mariya G.; Manolova, Nevena E.; Markova, Nadya D.; Rashkov, Iliya B.

2017-01-01

Novel fibrous materials from cellulose acetate (CA) and polyvinylpyrrolidone (PVP) containing curcumin (Curc) with original design were prepared by one-pot electrospinning or dual spinneret electrospinning. The electrospun materials were characterized by scanning electron microscopy (SEM), fluorescence microscopy, Fourier transform infrared spectroscopy (FTIR), ultraviolet-visible spectroscopy (UV–Vis), differential scanning calorimetry (DSC), water contact angle measurements, and microbiological tests. It was found that the incorporation of Curc into the CA and PVP solutions resulted in an increase of the solution viscosity and obtaining fibers with larger diameters (ca. 1.5 μm) compared to the neat CA (ca. 800 nm) and PVP fibers (ca. 500 nm). The incorporation of PVP resulted in increased hydrophilicity of the fibers and in faster Curc release. Curc was found in the amorphous state in the Curc-containing fibers and these mats exhibited antibacterial activity against Staphylococcus aureus (S. aureus). The results suggest that, due to their complex architecture, the obtained new antibacterial materials are suitable for wound dressing applications, which necessitate diverse release behaviors of the bioactive compound. - Highlights: • Novel curcumin-loaded materials based on cellulose acetate and polyvinylpyrrolidone were prepared by electrospinning. • Using one-pot or dual spinneret electrospinning enabled modulating drug release. • The incorporation of polyvinylpyrrolidone resulted in faster curcumin release. • The curcumin-containing mats exhibited antibacterial activity thus rendering them suitable for wound dressing applications.

Organometallic approach to polymer-protected antibacterial silver nanoparticles: optimal nanoparticle size-selection for bacteria interaction

Energy Technology Data Exchange (ETDEWEB)

Crespo, Julian; Garcia-Barrasa, Jorge; Lopez-de-Luzuriaga, Jose M.; Monge, Miguel, E-mail: miguel.monge@unirioja.es; Olmos, M. Elena [Universidad de La Rioja, Centro de Investigacion en Sintesis Quimica (CISQ), Departamento de Quimica (Spain); Saenz, Yolanda; Torres, Carmen [Centro de Investigacion Biomedica de La Rioja, Area de Microbiologia Molecular (Spain)

2012-12-15

The optimal size-specific affinity of silver nanoparticles (Ag NPs) towards E. coli bacteria has been studied. For this purpose, Ag NPs coated with polyvinylpyrrolidone (PVP) and cellulose acetate (CA) have been prepared using an organometallic approach. The complex NBu{sub 4}[Ag(C{sub 6}F{sub 5}){sub 2}] has been treated with AgClO{sub 4} in a 1:1 molar ratio giving rise to the nanoparticle precursor [Ag(C{sub 6}F{sub 5})] in solution. Addition of an excess of PVP (1) or CA (2) and 5 h of reflux in tetrahydrofuran (THF) at 66 Degree-Sign C leads to Ag NPs of small size (4.8 {+-} 3.0 nm for PVP-Ag NPs and 3.0 {+-} 1.2 nm for CA-Ag NPs) that coexist in both cases with larger nanoparticles between 7 and 25 nm. Both nanomaterials display a high antibacterial effectiveness against E. coli. The TEM analysis of the nanoparticle-bacterial cell membrane interaction shows an optimal size-specific affinity for PVP-Ag NPs of 5.4 {+-} 0.7 nm in the presence of larger size silver nanoparticles.Graphical AbstractAn organometallic approach permits the synthesis of small size silver nanoparticles (ca 5 nm) as a main population in the presence of larger size nanoparticles. Optimal silver nanoparticle size-selection (5.4 nm) for the interaction with the bacterial membrane is achieved.

Sum Frequency Generation Vibrational Spectroscopy of Colloidal Platinum Nanoparticle Catalysts: Disordering versus Removal of Organic Capping

KAUST Repository

Krier, James M.

2012-08-23

Recent work with nanoparticle catalysts shows that size and shape control on the nanometer scale influences reaction rate and selectivity. Sum frequency generation (SFG) vibrational spectroscopy is a powerful tool for studying heterogeneous catalysis because it enables the observation of surface intermediates during catalytic reactions. To control the size and shape of catalytic nanoparticles, an organic ligand was used as a capping agent to stabilize nanoparticles during synthesis. However, the presence of an organic capping agent presents two major challenges in SFG and catalytic reaction studies: it blocks a significant fraction of active surface sites and produces a strong signal that prevents the detection of reaction intermediates with SFG. Two methods for cleaning Pt nanoparticles capped with poly (vinylpyrrolidone) (PVP) are examined in this study: solvent cleaning and UV cleaning. Solvent cleaning leaves more PVP intact and relies on disordering with hydrogen gas to reduce the SFG signal of PVP. In contrast, UV cleaning depends on nearly complete removal of PVP to reduce SFG signal. Both UV and solvent cleaning enable the detection of reaction intermediates by SFG. However, solvent cleaning also yields nanoparticles that are stable under reaction conditions, whereas UV cleaning results in aggregation during reaction. The results of this study indicate that solvent cleaning is more advantageous for studying the effects of nanoparticle size and shape on catalytic selectivity by SFG vibrational spectroscopy. © 2012 American Chemical Society.

Transdermal therapeutic systems for memantine delivery. Comparison of passive and iontophoretic transport.

Science.gov (United States)

Del Río-Sancho, S; Serna-Jiménez, C E; Sebastián-Morelló, M; Calatayud-Pascual, M A; Balaguer-Fernández, C; Femenía-Font, A; Kalia, Y N; Merino, V; López-Castellano, A

2017-01-30

Memantine is a non-competitive N-methyl-d-aspartate (NMDA) receptor antagonist used in the treatment of moderate to severe dementia including the symptoms of Alzheimer's disease (AD). It is administered orally but compliance, swallowing problems and the routine use of multiple medications in elderly AD patients means that an alternative route of administration would be of interest. The aim of the present study was to develop memantine hydrochloride occlusive transdermal therapeutic systems (TTS) for passive and iontophoretic delivery across the skin. Polyvinyl pyrrolidone (PVP) and a mixture with polyvinyl alcohol (PVA) were employed as polymeric matrices. The study involved the TTS characterization in addition to quantification of the memantine transport across porcine skin in vitro. The evaluation of the TTS physical properties suggested that systems were made more mechanically resistant by including PVA (6%) or high concentrations of PVP (24%). Moreover, a linear correlation was observed between the concentration of PVP and the bioadhesion of the systems. Drug delivery experiments showed that the highest transdermal flux provided by a passive TTS (PVP 24% w/w limonene) was 8.89±0.81μgcm -2 h -1 whereas the highest iontophoretic transport was 46.4±3.6μgcm -2 h -1 . These innovative TTS would enable two dosage regimens that could lead to therapeutic plasma concentrations. Copyright © 2016 Elsevier B.V. All rights reserved.

An Imaging and Histological Study on Intrahepatic Microvascular Passage of Contrast Materials in Rat Liver

Directory of Open Access Journals (Sweden)

Qian Xia

2017-01-01

Full Text Available Background. Lipiodol has been applied for decades in transarterial chemoembolization to treat liver malignancies, but its intrahepatic pathway through arterioportal shunt (APS in the liver has not been histologically revealed. This rodent experiment was conducted to provide evidence for the pathway of Lipiodol delivered through the hepatic artery (HA but found in the portal vein (PV and to elucidate the observed unidirectional APS. Methods. Thirty rats were divided into 5 groups receiving systemic or local arterial infusion of red-stained iodized oil (RIO or its hydrosoluble substitute barium sulfate suspension (BSS, or infusion of BSS via the PV, monitored by real-time digital radiography. Histomorphology of serial frozen and paraffin sections was performed and quantified. Results. After HA infusion, RIO and BSS appeared extensively in PV lumens with peribiliary vascular plexus (PVP identified as the responsible anastomotic channel. After PV infusion, BSS appeared predominantly in the PV and surrounding sinusoids and to a much lesser extent in the PVP and HA (P<0.001. Fluid mechanics well explains the one-way-valve phenomenon of APS. Conclusions. Intravascularly injected rat livers provide histomorphologic evidences: (1 the PVP exists in between the HA and PV, which is responsible to the APS of Lipiodol; and (2 the intrahepatic vascular inflow appears HA-PVP-PV unidirectional without a physical one-way valve, which can be postulated by the fluid mechanics.

Electrospun curcumin-loaded cellulose acetate/polyvinylpyrrolidone fibrous materials with complex architecture and antibacterial activity

Energy Technology Data Exchange (ETDEWEB)

Tsekova, Petya B.; Spasova, Mariya G.; Manolova, Nevena E. [Laboratory of Bioactive Polymers, Institute of Polymers, Bulgarian Academy of Sciences, Acad. G. Bonchev St, bl. 103A, BG-1113 Sofia (Bulgaria); Markova, Nadya D. [Institute of Microbiology, Bulgarian Academy of Sciences, Acad. G. Bonchev St, bl. 26, BG-1113 Sofia (Bulgaria); Rashkov, Iliya B., E-mail: rashkov@polymer.bas.bg [Laboratory of Bioactive Polymers, Institute of Polymers, Bulgarian Academy of Sciences, Acad. G. Bonchev St, bl. 103A, BG-1113 Sofia (Bulgaria)

2017-04-01

Novel fibrous materials from cellulose acetate (CA) and polyvinylpyrrolidone (PVP) containing curcumin (Curc) with original design were prepared by one-pot electrospinning or dual spinneret electrospinning. The electrospun materials were characterized by scanning electron microscopy (SEM), fluorescence microscopy, Fourier transform infrared spectroscopy (FTIR), ultraviolet-visible spectroscopy (UV–Vis), differential scanning calorimetry (DSC), water contact angle measurements, and microbiological tests. It was found that the incorporation of Curc into the CA and PVP solutions resulted in an increase of the solution viscosity and obtaining fibers with larger diameters (ca. 1.5 μm) compared to the neat CA (ca. 800 nm) and PVP fibers (ca. 500 nm). The incorporation of PVP resulted in increased hydrophilicity of the fibers and in faster Curc release. Curc was found in the amorphous state in the Curc-containing fibers and these mats exhibited antibacterial activity against Staphylococcus aureus (S. aureus). The results suggest that, due to their complex architecture, the obtained new antibacterial materials are suitable for wound dressing applications, which necessitate diverse release behaviors of the bioactive compound. - Highlights: • Novel curcumin-loaded materials based on cellulose acetate and polyvinylpyrrolidone were prepared by electrospinning. • Using one-pot or dual spinneret electrospinning enabled modulating drug release. • The incorporation of polyvinylpyrrolidone resulted in faster curcumin release. • The curcumin-containing mats exhibited antibacterial activity thus rendering them suitable for wound dressing applications.

Preparation and characterization of nanocomposite polymer electrolytes poly(vinylidone fluoride)/nanoclay

Energy Technology Data Exchange (ETDEWEB)

Rahmawati, Suci A.; Sulistyaningsih,; Putro, Alviansyah Z. A.; Widyanto, Nugroho F.; Jumari, Arif; Purwanto, Agus; Dyartanti, Endah R., E-mail: endahrd@uns.ac.id [Research Group of Battery & Advanced Material, Department of Chemical Engineering, Sebelas Maret University, Jl. Ir. Sutami 36 A Kentingan, Surakarta Indonesia 57126 (Indonesia)

2016-02-08

Polymer electrolytes are defined as semi solid electrolytes used as separator in lithium ion battery. Separator used as medium for transfer ions and to prevent electrical short circuits in battery cells. To obtain the optimal battery performance, separator with high porosity and electrolyte uptake is required. This can reduce the resistance in the transfer of ions between cathode and anode. The main objective of this work is to investigate the impact of different solvent (Dimethyl acetamide (DMAc), N-methyl-2-pyrrolidone (NMP) and dimethyl formamide (DMF)), pore forming agent poly(vinylpyrolidone) (PVP) and nanoclay as filler in addition of membrane using phase inversion method on the morphology, porosity, electrolyte uptake and degree of crystallinity. The membrane was prepared by the phase inversion method by adding PVP and Nanoclay using different solvents. The phase inversion method was prepared by dissolving Nanoclay and PVP in solvent for 1-2 hours, and then add the PVDF with stirring for 4 hours at 60°C. The membranes were characterized by porosity test, electrolyte uptake test, scanning electron microscope (SEM), and X-ray diffraction (XRD). The results showed that DMAc as solvent gives the highest value of porosity and electrolyte uptake. The addition of nanoclay and PVP enlarge the size of the pores and reduce the degree of crystallinity. So, the usage of DMAc as solvent is better than NMP or DMF.

All-proportional solid-solution Rh–Pd–Pt alloy nanoparticles by femtosecond laser irradiation of aqueous solution with surfactant

Energy Technology Data Exchange (ETDEWEB)

Sarker, Md. Samiul Islam, E-mail: samiul-phy@ru.ac.bd; Nakamura, Takahiro; Sato, Shunichi [Tohoku University, Institute of Multidisciplinary Research for Advanced Materials (Japan)

2015-06-15

Formation of Rh–Pd–Pt solid-solution alloy nanoparticles (NPs) by femtosecond laser irradiation of aqueous solution in the presence of polyvinylpyrrolidone (PVP) or citrate as a stabilizer was studied. It was found that the addition of surfactant (PVP or citrate) significantly contributed to reduce the mean size of the particles to 3 nm for PVP and 10 nm for citrate, which was much smaller than that of the particles fabricated without any surfactants (20 nm), and improved the dispersion state as well as the colloidal stability. The solid-solution formation of the Rh–Pd–Pt alloy NPs was confirmed by the XRD results that the diffraction pattern was a single peak, which was found between the positions corresponding to each pure Rh, Pd, and Pt NPs. Moreover, all the elements were homogeneously distributed in every particle by STEM-EDS elemental mapping, strongly indicating the formation of homogeneous solid-solution alloy. Although the Rh–Pd–Pt alloy NPs fabricated with PVP was found to be Pt rich by EDS observation, the composition of NPs fabricated with citrate almost exactly preserved the feeding ratio of ions in the mixed solution. To our best knowledge, these results demonstrated for the first time, the formation of all-proportional solid-solution Rh–Pd–Pt alloy NPs with well size control.

Synthesis of PVA Hydrogel for Prosthetic Discus Nucleus Pulposus: Formation of Interpenetrating Polymer Network (IPN) PVA Hydrogel by Gamma Rays

International Nuclear Information System (INIS)

Darwis, Darmawan; Erizal; Lely Hardiningsih; Razzak, Mirzan T.

2004-01-01

Research on synthesis of IPN PVA hydrogel for using as prosthetic discus nucleus has been carried out. Base hydrogel network (network I) was made by reacting the solution of polyvinyl alcohol (PVA) 10 - 15 % w/w with formaldehyde at 80 o C for several hours. Hydrogel network II (as IPN network) was then made by immersion of base hydrogel into polymer solution (PVP or PVA) until hydrogel swell to equilibrium volume. The hydrogel then irradiated using gamma rays at various doses. The results show that IPN PVA-PVP and IPN PVA-PVP hydrogels have higher compression strength compared to base hydrogel. IPN PVA-PVA hydrogel made by irradiating base hydrogel (immersed into polymer solution) with 25, 50 and 100 kGy have compression strength at 5 mm displacement 2.72; 2.83; and 3.25 kg/cm 2 respectively, While base hydrogel has compression strength of 1.75 kg/cm 2 . IPN PVA-PVP and PVA-PVA hydrogels made by irradiating base hydrogel with 100 kGy still retain high water content i.e. 72 and 74 % respectively. Beside that they show good re-absorption property after compression treatment that is hydrogel can return to the original shape after compressed to 12 mm displacement (80% of initial height on hydrogel) at relatively short time, less than 15 minutes. (author)

A Simplified Method of Opacifying and Mixing Acrylic Cement for Percutaneous Vertebroplasty: A Clinical and In Vitro Study

International Nuclear Information System (INIS)

Teng Gaojun; He Shicheng; Deng Gang; Guo Jinhe; Fang Wen; Zhu Guangyu

2005-01-01

The objective of this study was to simplify the opacifying mixing process of the bone cement and contrast used for percutaneous vertebroplasty (PVP). We performed a biomechanical study of polymethyl methacrylate (PMMA) (Corinplast TM 3) using three different mixtures of PMMA, monomer, and contrast: group I, 2:1; group II, 3:2; group III, 3:2:1 ratio of powder/monomer/iodinated contrast (Omnipaque). In vitro biomechanical testing of ultimate compressive strength was carried out in all samples. Following the conclusion of a proper bone cement mixture regimen drawn from the in vitro study, PVP was performed in 125 patients: 58 with cancer, 12 with hemangioma, and 54 with osteoporotic fracture. The ultimate compressive strength in group III was decreased by 38% compared to groups II and I. Proper fluoroscopic visualization was achieved in all PVP procedures using this mixture. There were no major complications associated with injection of the cement mixture. Complete (CR) and partial response (PR) was obtained in 64% and 32.8%, respectively. No further vertebral collapse occurred during follow-up. The regimen using iodinated contrast for cement visualization during PVP provides a simple and convenient new method for mixing. Although the biomechanical strength is altered by the contrast medium added, it seems insignificant in clinical practice based on the authors' limited experience

Improvement of Physico-mechanical Properties of Partially Amorphous Acetaminophen Developed from Hydroalcoholic Solution Using Spray Drying Technique

Science.gov (United States)

Sadeghi, Fatemeh; Torab, Mansour; Khattab, Mostafa; Homayouni, Alireza; Afrasiabi Garekani, Hadi

2013-01-01

Objective(s): This study was performed aiming to investigate the effect of particle engineering via spray drying of hydroalcoholic solution on solid states and physico-mechanical properties of acetaminophen. Materials and Methods: Spray drying of hydroalcoholic solution (25% v/v ethanol/water) of acetaminophen (5% w/v) in the presence of small amounts of polyninylpyrrolidone K30 (PVP) (0, 1.25, 2.5 and 5% w/w based on acetaminophen weight) was carried out. The properties of spray dried particles namely morphology, surface characteristics, particle size, crystallinity, dissolution rate and compactibility were evaluated. Results: Spray drying process significantly changed the morphology of acetaminophen crystals from acicular (rod shape) to spherical microparticle. Differential scanning calorimetery (DSC) and x-ray powder diffraction (XRPD) studies ruled out any polymorphism in spray dried samples, however, a major reduction in crystallinity up to 65%, especially for those containing 5% w/w PVP was observed. Spray dried acetaminophen particles especially those obtained in the presence of PVP exhibited an obvious improvement of the dissolution and compaction properties. Tablets produced from spray dried samples exhibited excellent crushing strengths and no tendency to cap. Conclusions: The findings of this study revealed that spray drying of acetaminophen from hydroalcoholic solution in the presence of small amount of PVP produced partially amorphous particles with improved dissolution and excellent compaction properties. PMID:24379968

Surface characterization of selected polymer thin films by total-reflection x-ray fluorescence spectroscopy and x-ray reflectivity

International Nuclear Information System (INIS)

Innis, Vallerie Ann A.

2006-01-01

Development of available x-ray characterizations tools for grazing incidence techniques was done to be able to probe nano-size thin films. Alignment of a Philips x-ray powder diffractometer was improved to let it perform as an x-ray reflectometer. X-ray reflectometry was coupled with total-reflection x-ray fluorescence spectroscopy. Evaluation of the performance of this grazing incidence techniques was done by preparing polymer thin films of carboxymethylcellulose, carrageenan and polyvinylpyrrolidone (PVP). The thickness of the films were varied by varying the process parameters such as concentration, spin speed and spin time. Angle-dispersive total-reflection x-ray fluorescence spectroscopy profiles of three films showed film formation only in carrageenan and PVP. For both carrageenan and PVP, an increase in concentration yielded a corresponding increase in intensity of the fluorescent or scattered peaks. XRR profiles of carrageenan thin films yielded a mean value for the critical angle close to quartz substrate. Thickness measurements of the prepared carrageenan thin films showed that concentration was the main determinant for final film thickness over the other process parameters. Sulfur fluorescent intensity derived from the TXRF measurement showed a linear relationship with the measured thickness by XRR. For PVP, measured critical angle is lower than quartz. Poor adhesion of the polymer onto the substrate yielded a limited number of thickness measurements made from the XRR profiles. (Author)

The preliminary report on percutaneous vertebroplasty for cervical vertebral metastases

International Nuclear Information System (INIS)

Sun Gang; Jin Peng; Yi Yuhai; Xie Zonggui; Xie Zhiyong; Zhang Xuping; Zhang Dianxing

2004-01-01

Objective: To evaluate the treating effect of percutaneous vertebroplasty (PVP) for cervical vertebral metastasis, and to explore the cervical vertebral technique of percutaneous vertebroplasty. Methods: Eleven cases with single cervical vertebral metastasis underwent PVP, including C2 in 1 case, C3 in 2 cases, C4 in 4 cases, C5 in 3 cases, and C6 in 1 case. PVP was performed with the instruments and PMMA made in China. Anterolateral route was used under the guidance of fluoroscopy in 10 cases, and posterolateral route was used under the guidance of CT combined with fluoroscopy in 1 case of C 2 vertebra. PMMA was injected in the paste period. CT scans were performed before and after the procedures. Results: The successful puncturing of PVP was obtained in 100%. The percentage of lesion PMMA filling was more than 50% demonstrated by CT. The clinical data of 11 cases was followed up for 7 to 12 months. The rate of marked or complete pain relief was demonstrated in all cases (CR in 6 cases, PR in 5 cases) within 7 days, 7/10 in 6 months, and 5/9 in 12 months, respectively, after operation. There was no bleeding of the puncturing route or leakage of PMMA related complications with clinical performance. Conclusion: The clinical effect of percutaneous vertebroplasty for cervical vertebral metastasis was satisfied

The Impact of the Polymer Chain Length on the Catalytic Activity of Poly(N-vinyl-2-pyrrolidone)-supported Gold Nanoclusters

OpenAIRE

Haesuwannakij, Setsiri; Kimura, Tetsunari; Furutani, Yuji; Okumura, Kazu; Kokubo, Ken; Sakata, Takao; Yasuda, Hidehiro; Yakiyama, Yumi; Sakurai, Hidehiro

2017-01-01

Poly(N-vinyl-2-pyrrolidone) (PVP) of varying molecular weight (M w ?=?40-360?kDa) were employed to stabilize gold nanoclusters of varying size. The resulting Au:PVP clusters were subsequently used as catalysts for a kinetic study on the sized-dependent aerobic oxidation of 1-indanol, which was monitored by time-resolved in situ infrared spectroscopy. The obtained results suggest that the catalytic behaviour is intimately correlated to the size of the clusters, which in turn depends on the mol...

Percutaneous vertebroplasty of the entire thoracic and lumbar vertebrate for vertebral compression fractures related to chronic glucocorticosteriod use: Case report and review of literature

Energy Technology Data Exchange (ETDEWEB)

Tian, Qing Hwa; Wu, Chun Gen; Xiao, Quan; Ping; He, Cheng Jian; Gu, Yi Feng; Wang, Tao; Li, Ming Hua [Dept. of Diagnostic and Interventional Radiology, Shanghai Jiao Tong University Affiliated Sixth People' s Hospital, Shanghai (China)

2014-12-15

Glucocorticosteroid-induced osteoporosis is the most frequent of all secondary types of osteoporosis, and can increase the risk of vertebral compression fractures (VCFs). There are promising additions to current medical treatment for appropriately selected osteoporotic patients. Few studies have reported on the efficiency of percutaneous vertebroplasty (PVP) or kyphoplasty for whole thoracic and lumbar glucocorticosteroid-induced osteoporotic vertebral compression fractures. We report a case of a 67-year-old man with intractable pain caused by successional VCFs treated by PVP.

The Effect of Polymer Content on the Non-Newtonian Behavior of Acetaminophen Suspension

Directory of Open Access Journals (Sweden)

Eskandar Moghimipour

2013-01-01

Full Text Available Acetaminophen is used as an analgesic and antipyretic agent. The aim of the study was evaluation of the effect of different polymers on rheological behavior of acetaminophen suspension. In order to achieve controlled flocculation, sodium chloride was added. Then structural vehicles such as carboxymethyl cellulose (CMC, polyvinyl pyrrolidone (PVP, tragacanth, and magnesium aluminum silicate (Veegum were evaluated individually and in combination. Physical stability parameters such as sedimentation volume (F, redispersibility (n, and growth of crystals of the suspensions were determined. Also, the rheological properties of formulations were studied. The results of this study showed that the combination of suspending agents had the most physical stability and pseudoplastic behavior with some degree of thixotropy. Viscosity of suspensions was increased by adding NaCl 0.02%. Presence of PVP is necessary for improving rheological behavior of suspensions by NaCl. This may be related to the cross-linking between the carbonyl group in the PVP segment and Na+ ions.

The development and validation of a Chinese version of the Illness Attitude Scales: an investigation of university students.

Science.gov (United States)

Luo, Danyan; Zhang, Yinxi; Yu, Enyan; Tan, Yunfei; Tong, Zhou; Zhou, You; Chen, Wanzhen; Chai, Hao; Wang, Wei

2014-08-01

The Illness Attitude Scales (IAS) are considered as one of the most suitable instruments to screen hypochondriasis. Whether it has cross-cultural validity in China remains to be determined. In Chinese university students (141 women and 141 men), we have administered the IAS, the Zuckerman-Kuhlman Personality Questionnaire (ZKPQ), and the Plutchik-van Praag Depression Inventory (PVP). For the first time in Chinese culture, we have identified a four-factor structure of the IAS: patho-thanatophobia, symptom effect, treatment seeking, and hypochondriacal belief. Women scored significantly higher on IAS patho-thanatophobia and treatment seeking, on ZKPQ neuroticism-anxiety and activity, and on PVP than men did. The neuroticism-anxiety was significantly correlated with patho-thanatophobia and symptom effect, and PVP was positively correlated with symptom effect in women. Neuroticism-anxiety was significantly correlated with patho-thanatophobia, and impulsive sensation seeking and activity were significantly correlated with symptom effect in men. In Chinese students, we have found a stable four-factor IAS structure.

Sensitive Adsorptive Voltammetric Method for Determination of Bisphenol A by Gold Nanoparticle/Polyvinylpyrrolidone-Modified Pencil Graphite Electrode

Directory of Open Access Journals (Sweden)

Yesim Tugce Yaman

2016-05-01

Full Text Available A novel electrochemical sensor gold nanoparticle (AuNP/polyvinylpyrrolidone (PVP modified pencil graphite electrode (PGE was developed for the ultrasensitive determination of Bisphenol A (BPA. The gold nanoparticles were electrodeposited by constant potential electrolysis and PVP was attached by passive adsorption onto the electrode surface. The electrode surfaces were characterized by electrochemical impedance spectroscopy (EIS and scanning electron microscopy (SEM. The parameters that affected the experimental conditions were researched and optimized. The AuNP/PVP/PGE sensor provided high sensitivity and selectivity for BPA recognition by using square wave adsorptive stripping voltammetry (SWAdSV. Under optimized conditions, the detection limit was found to be 1.0 nM. This new sensor system offered the advantages of simple fabrication which aided the expeditious replication, low cost, fast response, high sensitivity and low background current for BPA. This new sensor system was successfully tested for the detection of the amount of BPA in bottled drinking water with high reliability.

Hybridization of polyvinylpyrrolidone to a binary composite of curcumin/α-glucosyl stevia improves both oral absorption and photochemical stability of curcumin.

Science.gov (United States)

Kadota, Kazunori; Okamoto, Daiki; Sato, Hideyuki; Onoue, Satomi; Otsu, Shigeyuki; Tozuka, Yuichi

2016-12-15

The tri-component system curcumin/α-glucosyl stevia (Stevia-G)/polyvinylpyrrolidone (PVP) was developed to improve the oral bioavailability and physicochemical properties of curcumin (CUR). The tri-component CUR formulation with Stevia-G and PVP was prepared with freeze-drying. The tri-component CUR system exhibited 13,000-fold higher solubility of CUR than the equilibrium solubility of CUR for 24h, indicating a stable tri-composite structure involving CUR. CUR could be converted into an amorphous form in the presence of Stevia-G and PVP by freeze-drying. The photo-degradation of CUR in the tri-component system was negligible even under an amorphous state of CUR. After oral administration in rats, the oral absorption of the tri-component CUR formulation (20mgCUR/kg) was 6.7-fold higher than that of crystalline CUR. The tri-component CUR formulation would therefore be a promising option to improve physicochemical properties and oral absorption of CUR. Copyright © 2016 Elsevier Ltd. All rights reserved.

Electrochemical behavior and voltammetric determination of vanillin based on an acetylene black paste electrode modified with graphene-polyvinylpyrrolidone composite film.

Science.gov (United States)

Deng, Peihong; Xu, Zhifeng; Zeng, Rongying; Ding, Chunxia

2015-08-01

The graphene-polyvinylpyrrolidone composite film modified acetylene black paste electrode (GR-PVP/ABPE) was fabricated and used to determine vanillin. In 0.1M H3PO4 solution, the oxidation peak current of vanillin increased significantly at GR-PVP/ABPE compared with bare ABPE, PVP/ABPE and GR/ABPE. The oxidation mechanism was discussed. The experimental conditions that exert influence on the voltammetric determination of vanillin, such as supporting electrolytes, pH values, accumulation potential and accumulation time, were optimized. Besides, the interference, repeatability, reproducibility and stability measurements were also evaluated. Under the optimal experimental conditions, the oxidation peak current was proportional to vanillin concentration in the range of 0.02-2.0 μM, 2.0-40 μM and 40-100 μM. The detection limit was 10nM. This sensor was used successfully for vanillin determination in various food samples. Copyright © 2015 Elsevier Ltd. All rights reserved.

Preparation and Performance Validation of Nano-Perovskite Type for Carbon Dioxide Reforming of Methane.

Science.gov (United States)

Kim, Taegyu; Park, Daeil

2018-02-01

This paper describes the La0.8Sr0.2NiO3 perovskite-type catalysts supported on α-Al2O3 that were prepared by polyol method and used as a catalyst for the carbon dioxide reforming of methane. The effect of the molar concentration of polyvinyl-pyrrolidone (PVP) on the reducibility, structural properties and carbon deposition was characterized by XRD, and TGA. The carbon dioxide reforming of methane on the catalyst was performed at the different concentration of PVP. At the 1 M PVP, main characteristic peaks of perovskite structure were established without impurities, thus showing the highest catalytic activity; 87.7% and 92.1% in CH4 and CO2 conversion, respectively. After the reaction, carbon deposition was 0.4-0.6%, while 6.2% on the existing Ni catalyst, indicating the perovskite-type catalyst has a superior characteristic preventing it from the carbon deposition at the carbon dioxide reforming of methane.

The Effect of Polymer Content on the Non-Newtonian Behavior of Acetaminophen Suspension

Science.gov (United States)

Moghimipour, Eskandar; Kouchak, Maryam; Salimi, Anayatollah; Bahrampour, Saeed; Handali, Somayeh

2013-01-01

Acetaminophen is used as an analgesic and antipyretic agent. The aim of the study was evaluation of the effect of different polymers on rheological behavior of acetaminophen suspension. In order to achieve controlled flocculation, sodium chloride was added. Then structural vehicles such as carboxymethyl cellulose (CMC), polyvinyl pyrrolidone (PVP), tragacanth, and magnesium aluminum silicate (Veegum) were evaluated individually and in combination. Physical stability parameters such as sedimentation volume (F), redispersibility (n), and growth of crystals of the suspensions were determined. Also, the rheological properties of formulations were studied. The results of this study showed that the combination of suspending agents had the most physical stability and pseudoplastic behavior with some degree of thixotropy. Viscosity of suspensions was increased by adding NaCl 0.02%. Presence of PVP is necessary for improving rheological behavior of suspensions by NaCl. This may be related to the cross-linking between the carbonyl group in the PVP segment and Na+ ions. PMID:24109512

The effectiveness of alcohol gel and other hand-cleansing agents against important nosocomial pathogens Eficácia do álcool gel e outros agentes degermantes na remoção de importantes patógenos hospitalares aplicados artificialmente nas mãos

Directory of Open Access Journals (Sweden)

Silvio Evandro Daniel Hernandes

2004-06-01

Full Text Available We compared the effectiveness of alcohol gel with that of the traditional hand-cleansing agents in removing clinical strains of Acinetobacter baumannii, methicillin-resistant Staphylococcus aureus, Escherichia coli, Enterococcus faecalis, Pseudomonas aeruginosa, and Candida albicans from artificially contaminated hands. The fingertips of 6 volunteers were contaminated with approximately 10(6 of microbial cells, and then were washed with: plain liquid soap, alcohol gel, 70% ethyl alcohol (by weight, 10% povidone-iodine liquid soap (PVP-I, and 4% chlorhexidine gluconate detergent. The experiments were performed using a Latin square statistical design, with six 6 x 5 randomized blocks, and the results were estimated by ANOVA. The products reduced from 93.83% (plain liquid soap to 100% (PVP-I of the microbial population applied to the hands. In 4 of 6 test microorganisms analyzed, 10% PVP-I, alcohol gel, 70% ethyl alcohol, and 4% chlorhexidine had significantly higher removal rates than plain liquid soap (P Nós comparamos a eficácia do álcool gel com a dos tradicionais agentes degermantes preconizados para a lavagem das mãos na remoção de amostras clínicas de Acinetobacter baumannii, Staphylococcus aureus resistente a meticilina, Escherichia coli, Enterococcus faecalis, Pseudomonas aeruginosa e Candida albicans das mãos artificialmente contaminadas. As pontas dos dedos dos voluntários (n=6 foram contaminadas com aproximadamente 10(6 de células/microrganismo teste. A seguir, as mãos foram lavadas com sabonete líquido não medicamentoso, álcool gel, álcool etílico 70% (concentração por peso e soluções anti-sépticas detergentes de polivinilpirrolidona-iodo a 10% (PVP-I e de gluconato de clorhexidina 4%. Os experimentos foram realizados segundo um quadrado latino com seis blocos aleatorizados 6 x 5. Os resultados foram estimados por ANOVA. Os produtos reduziram de 93,83% (sabão líquido a 100% (PVP-I 10% a população microbiana

Synthesis and Characterization of Nanoparticles and Nanocomposite of ZnO and MgO by Sonochemical Method and their Application for Zinc Polycarboxylate Dental Cement Preparation

OpenAIRE

Mohammad Ali Karimi; Saeed Haghdar Roozbahani; Reza Asadiniya; Abdolhamid Hatefi-Mehrjardi; Mohammad Hossein Mashhadizadeh; Reza Behjatmanesh-Ardakani; Mohammad Mazloum-Ardakani; Hadi Kargar; Seyed Mojtaba Zebarjad

2011-01-01

This paper discusses the synthesis of nanoparticles of ZnO and MgO and ZnO/MgO nanocomposite by the sonochemical method. At first, nanoparticles were synthesized by the reaction of Zn(CHCOO3)2 and Mg(CHCOO3)2 with tetramethylammonium hydroxide (TMAH) in the presence of polyvinyl pyrrolidone (PVP) and constant frequency ultrasonic waves (sonochemical method). Then, ZnO/MgO nanocomposite was prepared through reaction of magnesium acetate with TMAH in the presence of ZnO nanoparticles and PVP as...

Semi-transparent a-IGZO thin-film transistors with polymeric gate dielectric.

Science.gov (United States)

Hyung, Gun Woo; Wang, Jian-Xun; Li, Zhao-Hui; Koo, Ja-Ryong; Kwon, Sang Jik; Cho, Eou-Sik; Kim, Young Kwan

2013-06-01

We report the fabrication of semi-transparent a-IGZO-based thin-film transistors (TFTs) with crosslinked poly-4-vinylphenol (PVP) gate dielectric layers on PET substrate and thermally-evaporated Al/Ag/Al source and drain (S&D) electrodes, which showed a transmittance of 64% at a 500-nm wavelength and sheet resistance of 16.8 omega/square. The semi-transparent a-IGZO TFTs with a PVP layer exhibited decent saturation mobilities (maximum approximately 5.8 cm2Ns) and on/off current ratios of approximately 10(6).

Poly(vinylpyrrolidone)/silver nanoparticles: preparation and characterization; Nanoparticulas de prata/poli(vinilpirrolidona): obtencao e caracterizacao

Energy Technology Data Exchange (ETDEWEB)

Andrade, P.F.; Goncalves, M.C. [Instituto de Quimica - UNICAMP, Campinas, SP (Brazil)], e-mail: patandrade@iqm.unicamp.br

2010-07-01

In this work silver nanoparticles were prepared by chemical reduction method using PVP as dispersant agent. The formation of silver nanoparticles was investigated by UV-vis optical spectroscopy and X-ray diffraction. FT-IR spectroscopy confirmed the formation of Ag/PVP complex. The transmission electron microscopy images indicated that the concentration of Ag{sup +} precursor influenced the nanoparticles dispersion and size distribution significantly. The results indicated that dispersed nanoparticles with uniform size distribution can be prepared by this methodology to obtain polymeric nano composites. (author)

Evaluation of povidone-iodine applications in cataract surgery

Directory of Open Access Journals (Sweden)

Xi Zhang

2013-09-01

Full Text Available As a routine measure to prevent intraocular inflammation, rinsing conjunctival sac with povidone-iodine(PVP-Ihas been increasingly adopted in cataract surgery. It can effectively reduce the complications of cataract surgery, including endophthalmitis and corneal complications. However, PVP-I itself has certain side effects. Therefore, to achieve the best bactericidal effect and to avoid eye injury, it is necessary to find out the optimal treatment duration and concentration. This article offers a review on the latest researches worldwide in this field.

Oxygen permeability of the pigmented material used in cosmetic daily disposable contact lenses

Directory of Open Access Journals (Sweden)

Galas S

2016-12-01

Full Text Available Stephen Galas, Lenora L Copper Johnson & Johnson Vision Care Inc., Jacksonville, FL, USA Purpose: To evaluate the individual contributions of pigment colorant and packing solution containing polyvinyl pyrrolidone (PVP on the oxygen permeability (Dk of a cosmetic printed etafilcon A daily disposable contact lens packaged with PVP. Method: The oxygen transport of a contact lens is evaluated through the central optical zone of the lens. Cosmetic printed contact lenses contain pigment colorant in the periphery or mid-periphery of the lens. Therefore, to assess the impact of cosmetic print on oxygen permeability, special lenses need to be produced that contain the colorant within the central optical zone. This technique was used to obtain multiple measurements of nonedge-corrected Dk/t of both the center pigmented lens and its nonpigmented equivalent, using a polarographic measurement described in International Organization for Standardization (ISO 18369-4:2006(E, and the Dk derived for each measurement is corrected for edge effect. In addition, the edge-corrected Dk values of lenses made from the same monomer batch were measured. The lenses were packaged and autoclaved with and without proprietary technology which embeds PVP in the contact lens during autoclaving. The resulting Dk value of the printed lens material was then used with thickness data to generate true Dk/t profiles for a given lens power. Results: The edge-corrected Dk of the printed etafilcon A lens with offset pigment colorant was measured to be 19.7×10-11 (cm2/s (mL O2/mL·mmHg at 35°C. This was within ±20% tolerance range as specified in ISO 18369-2:2012(E for the edge-corrected Dk of the nonpigmented etafilcon A control lens evaluated during the same session, 19.5×10-11 (cm2/s (mL O2/mL·mmHg. The edge-corrected Dk values of the lenses packaged with PVP (mean 20.1, standard deviation [SD] 0.3 were also within the ±20% tolerance range compared to those packaged without PVP

Colorimetric detection of endogenous hydrogen sulfide production in living cells

Science.gov (United States)

Ahn, Yong Jin; Lee, Young Ju; Lee, Jaemyeon; Lee, Doyeon; Park, Hun-Kuk; Lee, Gi-Ja

2017-04-01

Hydrogen sulfide (H2S) has received great attention as a third gaseous signal transmitter, following nitric oxide and carbon monoxide. In particular, H2S plays an important role in the regulation of cancer cell biology. Therefore, the detection of endogenous H2S concentrations within biological systems can be helpful to understand the role of gasotransmitters in pathophysiology. Although a simple and inexpensive method for the detection of H2S has been developed, its direct and precise measurement in living cells remains a challenge. In this study, we introduced a simple, facile, and inexpensive colorimetric system for selective H2S detection in living cells using a silver-embedded Nafion/polyvinylpyrrolidone (PVP) membrane. This membrane could be easily applied onto a polystyrene microplate cover. First, we optimized the composition of the coating membrane, such as the PVP/Nafion mixing ratio and AgNO3 concentration, as well as the pH of the Na2S (H2S donor) solution and the reaction time. Next, the in vitro performance of a colorimetric detection assay utilizing the silver/Nafion/PVP membrane was evaluated utilizing a known concentration of Na2S standard solution both at room temperature and at 37 °C in a 5% CO2 incubator. As a result, the sensitivity of the colorimetric assay for H2S at 37 °C in the incubator (0.0056 Abs./μM Na2S, R2 = 0.9948) was similar to that at room temperature (0.0055 Abs./μM Na2S, R2 = 0.9967). Moreover, these assays were less sensitive to interference from compounds such as glutathione, L-cysteine (Cys), and dithiothreitol than to the H2S from Na2S. This assay based on the silver/Nafion/PVP membrane also showed excellent reproducibility (2.8% RSD). Finally, we successfully measured the endogenous H2S concentrations in live C6 glioma cells by s-(5‧-adenosyl)-L-methionine stimulation with and without Cys and L-homocysteine, utilizing the silver/Nafion/PVP membrane. In summary, colorimetric assays using silver/Nafion/PVP

Relationship between Plasma D-Dimer Concentration and Three-Dimensional Ultrasound Placental Volume in Women at Risk for Placental Vascular Diseases: A Monocentric Prospective Study.

Directory of Open Access Journals (Sweden)

Cécile Fanget

Full Text Available The aim of this study was to correlate placental volumes deduced from three-dimensional ultrasound and virtual organ computer-aided analysis (VOCAL software with systemic concentrations of D-dimer and soluble endothelial protein C receptor (sEPCR.This was a monocentric experimental prospective study conducted from October 2008 to July 2009. Forty consecutive patients at risk of placental vascular pathology (PVP recurrence or occurrence were included. Placental volumes were systematically measured three times (11-14, 16-18 and 20-22 weeks of gestation (WG by two independent sonographers. D-dimers and sEPCR plasma concentrations were measured using ELISA kits (Enzyme Linked ImmunoSorbent Assay.Eleven patients had a PVP. The plasma D-dimer level was positively correlated with placental volume (r = 0.45, p < 0.001. A smaller placental volume and placental quotient was evidenced in women who developed a PVP at the three gestational ages, and the difference was more pronounced during the third exam (20 WG. No obvious correlation could be demonstrated between the development of a PVP and the levels of D-dimer and sEPCR. There was no significant difference in the values of placental volumes measured by the two sonographers.The placenta growth could be a major determinant of the elevation of D-dimer during pregnancy. Consideration of placental volume could allow for modulation of the D-dimer concentrations for restoring their clinical interest.

Surface plasmon resonance based fiber optic detection of chlorine utilizing polyvinylpyrolidone supported zinc oxide thin films.

Science.gov (United States)

Tabassum, Rana; Gupta, Banshi D

2015-03-21

A highly sensitive chlorine sensor for an aqueous medium is fabricated using an optical fiber surface plasmon resonance (OFSPR) system. An OFSPR-based chlorine sensor is designed with a multilayer-type platform by zinc oxide (ZnO) and polyvinylpyrollidone (PVP) film morphology manipulations. Among all the methodologies of transduction reported in the field of solid state chemical and biochemical sensing, our attention is focused on the Kretschmann configuration optical fiber sensing technique using the mechanism of surface plasmon resonance. The optical fiber surface plasmon resonance (SPR) chlorine sensor is developed using a multimode optical fiber with the PVP-supported ZnO film deposited over a silver-coated unclad core of the fiber. A spectral interrogation mode of operation is used to characterize the sensor. In an Ag/ZnO/PVP multilayer system, the absorption of chlorine in the vicinity of the sensing region is performed by the PVP layer and the zinc oxide layer enhances the shift in resonance wavelength. It is, experimentally, demonstrated that the SPR wavelength shifts nonlinearly towards the red side of the visible region with an increase in the chlorine concentration in an aqueous medium while the sensitivity of the sensor decreases linearly with an increase in the chlorine concentration. As the proposed sensor utilizes an optical fiber, it possesses the additional advantages of fiber such as less signal degradation, less susceptibility to electromagnetic interference, possibility of remote sensing, probe miniaturization, probe re-usability, online monitoring, small size, light weight and low cost.

Influence of intravertebral cleft on percutaneous vertebroplasty outcome of osteoporotic vertebral compression fractures

International Nuclear Information System (INIS)

Zhu Xuee; Wu Chungen; Zhang Ji; Cheng Yongde; Gu Yifeng; Li Minghua; Hu Xiaohui

2008-01-01

Objective: To evaluate the influence of intravertebral cleft on percutaneous vertebroplasty (PVP)outcome and the efficacy in the treatment of osteoporotic compression fracture and compare to those without intravertebral cleft. Methods: A retrospective study was conducted to review 95 consecutive PVP procedures for 176 compression fractures. Patients were excluded with more than a single vertebral body involvement neoplasm history, lack of complete imaging materials and follow-up of incoordinated patients. Group A consisted of 18 patients with intravertebral cleft, while group B comprised 25 patients without intravertebral cleft. PMMA leakages were classified as intradiscal, perivertebral soft tissue, perivertebral venous and epidural types. The frequencies of leakage were compared between two groups using χ 2 and Fisher exact tests. Visual analogue scale (VAS)and Owestry disability index (ODI)scores were recorded before hand. Results: After PVP, all patients showed significant pain relief and improvement of daily activity function(P 0.05)between the two groups. PMMA leakage occurred in 11 (61.1%)of 18 fractures with intravertebral clefts and 15 (60%)of 25 fractures without intravertebral clefts, revealing no significant difference, but existing between the most frequent seen types in both groups (P < 0.05). Conclusions: PVP is an effective treatment for osteoporotic compression fractures with and without intravertebral cleft. There was no influence of intravertebral clefts on pain relief, improvement of daily activity function and incidence of PMMA leakage besides the PMMA leakage types. (authors)

BiOI/TiO2-nanorod array heterojunction solar cell: Growth, charge transport kinetics and photoelectrochemical properties

International Nuclear Information System (INIS)

Wang, Lingyun; Daoud, Walid A.

2015-01-01

Highlights: • BiOI/TiO 2 photoanodes were fabricated by a simple solvothermal/hydrothermal method. • BiOI/TiO 2 (PVP) showed a 13-fold increase in photocurrent density compared to TiO 2 . • Charge transport kinetics within the BiOI/TiO 2 heterojunctions are discussed. - Abstract: A series of BiOI/TiO 2 -nanorod array photoanodes were grown on fluorine-doped tin oxide (FTO) glass using a simple two-step solvothermal/hydrothermal method. The effects of the hydrothermal process, such as TiO 2 nanorod growth time, BiOI concentration and the role of surfactant, polyvinylpyrrolidone (PVP), on the growth of BiOI, were investigated. The heterojunctions were characterized by X-ray diffraction, UV–vis absorbance spectroscopy and scanning electron microscopy. The photoelectrochemical properties of the as-grown junctions, such as linear sweep voltammetry (LSV) behavior, photocurrent response and incident photon-to-electron conversion efficiency (IPCE) under Xenon lamp illumination, are presented. The cell with BiOI/TiO 2 (PVP) as photoanode can reach a short current density (J sc ) of 0.13 mA/cm 2 and open circuit voltage (V oc ) of 0.46 V vs. Ag/AgCl under the irradiation of a 300 W Xenon lamp. Compared to bare TiO 2 , the IPCE of BiOI/TiO 2 (PVP) increased 4–5 times at 380 nm. Furthermore, the charge transport kinetics within the heterojunction is also discussed

Studying Of Preparation Silver Nano-Particles Using Spinning Disc Reactor

International Nuclear Information System (INIS)

Hoang Van Duc; Nguyen Thanh Chung; Tran Ngoc Ha; Ho Minh Quang; Nguyen Thi Thuc Phuong

2014-01-01

Preparation of silver nano-particles using spinning disc reactor has been investigated. The effects of technological factors and experimental conditions such as: concentrations of AgNO 3 , glucose, PVP, spinning speed, ect. on quality of nano-silver particles have been studied. With experimental conditions: rotation speed of 2000 rpm, weight rate of m PVP :m AgNO 3 = 1, AgNO 3 concentration of 0.01 M, glucose concentration of 0.02 M, silver particles of about 12 nm were obtained and the nano-silver solution were stable for more than 40 days. (author)

Radioprotective preparation

International Nuclear Information System (INIS)

Stefanova, D.; Frattadochi, A.; Gattavecchia, E.; Ferri, E.; Tonnelli, D.

1988-01-01

The invention is intended for radiation injuries prophylaxis in mammals. It has an well expressed radioprotective effect against acute gamma irradiation on cellular level as well as a prolonged action when applied up to 48 hours before the acute irradiation. The preparation is a coprecipitate of the natural tripeptide glutathione (reduced form) and polyvinyl pyrrolidone (pvp) in ratio 30-60/70-40. It is obtained by incubation method with subsequent lyophilization from water solution of the initial components. The molecular mass of the pvp is 20 till 360.10 3 . 2 claims

Direct hydrodeoxygenation of cellulose and xylan to lower alkanes on ruthenium catalysts in subcritical water

International Nuclear Information System (INIS)

Osaka, Yuriko; Ikeda, Yoichi; Hashizume, Daisuke; Iwamoto, Masakazu

2013-01-01

Nano particles of Ru, Rh, Pd, Ir, Pt, and Au, protected by polyvinyl pyrrolidone (PVP), were applied to the hydrodeoxygenation of cellulose and xylan in water and 5 MPa H 2 at 543 K. The distributions of products generated from cellulose and xylan were roughly similar to each other under the present reaction conditions, and therefore, the former was intensively studied. The Ru-PVP catalyst afforded mainly methane and lower alkanes, rather than producing water soluble organic compounds, such as diols and alcohols, that were formed with the use of the other catalysts. The changes in the product distributions with reaction temperature and time indicated that the reaction consisted of two consecutive reactions: cellulose or xylan → water soluble compounds → hydrogenolysis. The first transformation was promoted in subcritical water, and the second step was catalyzed by the Ru catalyst. The Ru catalyst that was supported on CeO 2 , γ-Al 2 O 3 , or activated carbon yielded a similar product distribution to that on Ru-PVP; however, the loading of Ru on TiO 2 , ZrO 2 , SiO 2 –Al 2 O 3 , or SiO 2 resulted in the increment of diols. After the reaction a small portion of the CeO 2 and most of the SiO 2 –Al 2 O 3 and SiO 2 were dissolved in water, and a portion of the Al 2 O 3 was transformed to boehmite AlO(OH) from the γ-alumina. Little change in the catalytic activity however was observed upon the reuse of Ru/Al 2 O 3 in the second run. Highlights: •One-path hydrodeoxygenation of cellulose and xylan to methane and lower alkanes was studied. •Ru-PVP catalysts gave the best yields among Ru-, Rh-, Pd-, Ir-, Pt-, and Au-PVP. •The reaction pathways were cellulose → water soluble compounds → hydrogenolysis. •The catalytic activity of Ru was greatly dependent on the supports

Unusual anti-leukemia activity of nanoformulated naproxen and other non-steroidal anti-inflammatory drugs

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