• Resources Recycling
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• v.15 no.5 s.73
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• pp.33-37
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• 2006

An equal-molar mixture of silver chloride (AgCl) and copper (Cu) was ground in atmosphere conditions using a planetary ball mill to investigate mechanochemical (MC) reaction for preparation of silver powders. The reaction causes the mixture of AgCl and Cu to change the composition of the mixture, such as silver (Ag) and cuprous chloride (CuCl). Through the leaching with ammonium hydroxide solution (1 mol), CuCl can be separated from MC product, so that pure Ag powders can be obtained as the final product. Moreover, polyvinylpyrrolidone (PVP) was used as the additive not only to improve dispersion of Ag pow- der during MC process, but also to control surface oxidation of Ag powders, prepared as the final product.

• Journal of the Korean Applied Science and Technology
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• v.18 no.3
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• pp.233-240
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• 2001

The transparent organic-inorganic hybrid films were prepared by the Sol-Gel process. PVP(polyvinylpyrrolidone) was used in organic component and TEOS(tetraethoxysilane) was used in inorganic component. HCI, $CH_{3}COOH$, and $NH_{4}OH$ were used as the Sol-Gel catalyst. The characteristics according to not only the variation of organic and inorganic contents but also the variation of catalyst species and contents were investigated. On the whole, the compatibility was remained between organic and inorganic components, and also as the TEOS contents were increased, mostly the transparency and the mechanical, thermal properties were improved. In addition, as content of catalysts was increased, the films showed characteristics that were closer to PVP than silica. Although the transparency of films was preserved in HCI and $CH_{3}COOH$, only the film containing more than 40wt% TEOS in $NH_{4}OH$ showed different phenomena.

• Asian-Australasian Journal of Animal Sciences
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• v.16 no.1
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• pp.23-28
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• 2003

The present study was undertaken to investigate the effects of PVP concentration and exposure temperature to vitrification solution on the post-thaw survival, in vitro maturation and development of immature bovine oocytes (germinal vesicle stage). The vitrification solution (VS) consisted of 40% ethylene glycol (EG)+0.5 M sucrose (S)+10% FBS. PVP was added to VS: 0%, 5% or 10%. The cumulus-oocyte complexes (COCs) were diluted in VS as one step, after 2 min the COCs were loaded in straw and vitrified by direct immersion into liquid nitrogen. For thawing, the straws were plunged into $30^{\circ}C$ water bath for 10s. After thawing, the oocytes were diluted in 0.5 M (in DPBS with 10% FBS) sucrose solution for 5 min. The survival rate (FDA-test and trypan blue) of immature bovine oocytes was measured. The survival rate was higher in 5% PVP (91.5%) than in 0% (64.2%) or in 10% PVP (79.7%). The proportion of metaphase II formation was 69.35% in control (no vitrified COCs), 9.3% in 40% EG+0.5 M S+0% PVP and 21.05% in 40% EG+0.5 M S+5% PVP (p<0.05). The effect of room temperature ($25^{\circ}C$ for 10 min) and cold temperature ($4^{\circ}C$ for 10 min) on COCs were determined in this study. After IVF, the cleavage and blastocysts rate of oocytes exposed to room temperature and cold temperature in VS+5% PVP was significantly different (2 cell: 63.20% vs 37.97%, blastocysts: 18.40% vs 2.53%). The cleavage rates of frozen-thawed oocytes were 20.53% with PVP and 22.13% without PVP (p>0.05). Two out of 151 oocytes (1.32%) developed to blastocyst stage after frozen-thawed with 5% PVP (p>0.05). Development of oocytes after frozen-thawing to the 2 cell were not significantly affected with or without PVP following IVF. However, the vitrification of immature bovine oocytes with PVP maintained the ability to develop to the blastocyst stage after IVM-IVF and IVC, while no blastocysts were obtained from oocytes vitrified without PVP. These results suggested that PVP has a protective role for vitrification of immature bovine oocytes as far as survival is concerned, however, the protection was not sufficient enough to support blastocyst formation.

• Journal of Pharmaceutical Investigation
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• v.27 no.4
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• pp.287-293
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• 1997

To make a stable o/w emulsion, the effects of egg lecithin as an emulsifier and polyvinylpyrrolidone (PVP) as an auxiliary emulsifier on the physical stability of emulsion were investigated. The oil-in-water emulsion system was manufactured by microfluidizer and evaluated the physical stability. Average particle size and size distribution of emulsion was measured by dynamic light scattering analyzer and interfacial tension was measured. From the interfacial tension tested, critical micelle concentration of the egg lecithin was 0.1 %w/v and optimal concentration for the preparation of emulsion was 1.0 %w/v. The mean particle size was about $0.2\;{\mu}m$ which was suitable for injections. The short-term accelerated stability studies were conducted by centrifugation, freeze-thaw method and shaking of the emulsion samples. The addition of PVP was caused the reduction in the particle size and improved the physical stability of emulsion. These results suggested that a mixed interfacial film comprising the egg lecithin and PVP was formed at the o/w interface and it was effective in preventing phase separation under thermic or mechanical stress. We used antineoplaston A10 (A10) as a model drug which is peptide and amino acid derivative having a action to the living organism against the development of neoplastic growth by a nonimmunological progress. It has a poor solubility in water and there may be a difficulty in formulation of A10. Emulsion formulation study about A10 was performed. Solubility of A10 in emulsion was about five times as high as that in water. From the results of solubility and partition coefficient, almost A10 molecules in o/w emulsion exist in the interface between oil and water.

• Journal of Embryo Transfer
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• v.11 no.3
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• pp.211-216
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• 1996

A series of experiments were designed to determine the feasibility of single dose of FSH as an effective superovulation method in rabbits. The superovulation treatments examined comparatively were as follows: 1) a single injection of 100 IU PMSG, 2) Multiple injections of 1 IU Super-OV of 2X daily for 3 days, 3) Multiple injections of 6.6 rng Folltropin-V 2X daily for 3 days, 4) Multiple injections of 13.3 rng Folltropn-V l$\times$ daily for 3 days, 5) Single injection of 40 mg Folltropin-V solved in 10% PVP, and 6) Single injection of 40 mg Folltropin-V dissolved in 25% PVP. The results obtained were as follows: The nurnher of ovulation points in the single injection of 40 mg Folltropin-V dissolved in 25% PVP and multiple injections of 6.6 mg Folltropin-V 2X daily for 3 days was averaged 44.6 and 39.2, respectively, which were significantly (P<0.05) more than in a single dose of PMSG or multiple doses of Super-OV. The number of total ova recovered in the single injection of 40 mg Folltropin-V dissolved in 25% PVP and multiple injections of 6.6 mg Folltropin-V 2X daily for 3 days was averaged 30.4 and 25.9, respectively, which were significantly (P<0.05) more than in the single dose of PMSG or multiple doses of Super-OV. A similar result was obtained for the number of fertilized ova recovered from the above six treatments. From the above results it was concluded that a single injection of 40 mg Folltropin-V dissolved in 25% PVP could be an effective and simple method for superovulation in rabbits.

• Korean Journal of Materials Research
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• v.23 no.11
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• pp.631-637
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• 2013

Synthesis of sub-micron $2SnO{\cdot}(H_2O)$ powders by chemical reduction process was performed at room temperature as function of viscosity of methanol solution and molecular weight of PVP (polyvinylpyrrolidone). Tin(II) 2-ethylhexanoate and sodium borohydride were used as the tin precursor and the reducing agent, respectively. Simultaneous calcination and sintering processes were additionally performed by heating the $2SnO{\cdot}(H_2O)$ powders. In the synthesis of the $2SnO{\cdot}(H_2O)$ powders, it was possible to control the powder size using different combinations of the methanol solution viscosity and the PVP molecular weight. The molecular weight of PVP particularly influenced the size of the synthesized $2SnO{\cdot}(H_2O)$ powders. A holding time of 1 hr in air at $500^{\circ}C$ sufficiently transformed the $2SnO{\cdot}(H_2O)$ into $SnO_2$ phase; however, most of the PVP (molecular weight: 1,300,000) surface-capped powders decomposed and was removed after heating for 1 h at $700^{\circ}C$. Hence, heating for 1 h at $500^{\circ}C$ made a porous $SnO_2$ film containing residual PVP, whereas dense $SnO_2$ films with no significant amount of PVP formed after heating for 1 h at $700^{\circ}C$.

• Journal of Pharmaceutical Investigation
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• v.22 no.4
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• pp.307-315
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• 1992

Dissolution rate of practically insoluble mefenamic acid was improved by roll mixing with sodium lauryl sulfate (SLS) or polyvinylpyrrolidone (PVP). The dissolution rate of the drug roll mixtures with SLS was superior to that of roll mixtures with PVP. The maximal dissolution rate was found in the roll mixtures system with SLS content of 60%. The dissolution rate of mefenamic acid roll mixtures with SLS content of 60% reached to the maximum value after 10 min of roll mixing. The transport of roll mixtures with SLS across rat jejunum was studied by the perfusion method using everted rat jejunum in vitro. The absorption rate of roll mixtures was superior to that of mefanamic acid.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.51 no.12
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• pp.601-607
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• 2002

IPMC(Ionic Polymer Metal Composite)actuators were optimized for producing improved forces by changing multiple parameters including repetition of number of plating, surface electroding and additive(PVP)-treatment on reduction. The platinum electrode is deposited on the surface of the material where platinum particle stay in a dense form that appears to introduce a significant level of surface electrode resistance. Actuation tests were performed for such IPMC actuators under a low voltage. The test results show that the lower surface-electrode resistance generates higher actuation capability in the IPMC actuators. In order to investigate relaxation behavior of bending and repeatability in dry condition, the IPMC was coated by$rubber(KRATON^{TM})$to minimize the effect of water evaporation from IPMC. This actuator can be used in air with surface coating to avoid membrane drying.

• Bulletin of the Korean Chemical Society
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• v.30 no.11
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• pp.2669-2674
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• 2009

Controlled reduction of silver alkylcarbamate complexes with hydrogen gas was investigated as a facile synthetic method for high concentrations of silver nanocolloids in organic solvent. Polyvinylpyrrolidone (PVP) was used to stabilize the silver colloids obtained from the chemical reduction. To determine optimum conditions for preparation of the stable and controlled silver colloids with the narrowest particle size and distribution, a large number of experiments were carried out involving variations in the concentrations of the silver 2-ethylhexylcarbamate (Ag-EHCB) complex, PVP, and 2-propanol. The initial colloid had a mean particle diameter between 5$\sim$50 nm, as measured by transmission electron microscopy, and exhibited a sharp absorption band in the UV region with a maximum size near 420 nm. After treatment with a reducing agent, the colloids were characterized by ultraviolet-visible spectroscopy, X-ray diffraction, and high-resolution transmission electron microscopy.

• YAKHAK HOEJI
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• v.31 no.1
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• pp.42-44
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• 1987

Ziperol, anti-tussive, is considerably bitter. Therefore, it is necessary to mitigate the bitterness in ziperol syrup for children. In this experiment, it was attempted to mitigate the bitterness of zipeprol by means of polymers such as $\beta$-cyclodextrin, arabic gum, HPMC(hydroxypropyl methylcellulose), PEG 2000(polyethyleneglycol 2000), PVP(polyvinylpyrrolidone). Caffeine was used as the reference standard of bitterness. In the result of this experiment, $\beta$-cyclodextrin, would mitigate the bitterness of zipeprol more largely than any other polymers. Arabic gum was the second choice which would mitigate the bitterness of zipeprol.