• Title/Summary/Keyword: Buffer Stability

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Hepatic Uptake and Stability of Acyclovir-Asialofetuin Conjugate (아시클로버-아시알로페투인 접합체의 간 포획 및 안정성)

  • Son, Sung-Ho;Huh, Keun;Lee, Young-Dae;Oh, Doo-Man;Yong, Chul-Soon
    • Journal of Pharmaceutical Investigation
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    • v.27 no.1
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    • pp.1-10
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    • 1997
  • For the purpose of improving the chemotherapeutic index of acyclovir(ACV), it was conjugated with asialofetuin(AF), which has been reported to enter into hepatocytes. When $[H^3]$ acyclovir in itself or its conjugate were administered to rats, the latter was taken up more selectively by the liver than any other tissues. The stability of ACVMP-AF conjugate in phosphate buffer (pH 5.0) and rat liver homogenate showed a pseudo-first order profile. ACVMP-AF, however, was relatively stable in pH7.4 phosphate buffer and rat plasma. The conjugate was added to the isolated rat hepatocyte and cellular uptake was monitored by scintillation counting for up to 6 hours at $37^{\circ}C$. Hepatocytes incubated with the conjugate exhibited radioactivities significantly enhanced over control levels dose-dependently, i.e., a 3-40 fold increase in radioactivities was observed over controls at the conjugate concentrations of $0.1-10\;{\mu}g/ml$. The AUQ in the liver, kidney, spleen, intestine and lung was higher in treatment with ACVMP-AF than that in treatment with ACV. In treatment with ACVMP-AF, the weighted-average overall drug targeting efficiency(Te) for the liver was higher than in treatment with ACV(57.00 vs 13.31 %), and the weighted-average tissue exposure(Re) was 5.03 for the liver. These results indicated that ACVMP-AF conjugate was rapidly taken up by hepatocytes and could be an efficient and selective hepatic targeting system.

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Effect of Cattle Breeds on Milk Composition and Technological Characteristics in China

  • Yang, T.X.;Li, H.;Wang, F.;Liu, X.L.;Li, Q.Y.
    • Asian-Australasian Journal of Animal Sciences
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    • v.26 no.6
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    • pp.896-904
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    • 2013
  • Cattle breeds have a striking effect on milk, including milk composition and technological characteristics. This study aims to compare milk composition, acidification activity, viscosity, milk dispersion system stability and casein molecular weight among three buffalo breeds in China. The technological characteristics of milk produced by three cattle breeds of river buffalo (Murrah), crossbreed 1st generation ($F_1$), crossbreed multiple generation ($F_H$, $H{\geq}3$) buffaloes were investigated. Cattle breeds showed evident effect on milk protein, fat and total solids content, but little effect on most of buffalo casein molecular weight. Milk fat, protein content and the viscosity of buffalo milk from river buffalo were lower than those of $F_1$ and $F_H$, so was the buffer capacity. The viscosity was negatively correlated to temperature and concentration. Results of stability coefficient showed that milk dispersion system had the best dynamic stability characteristics under pH 6.6 and 6 times dilution, while zeta potential of Murrah milk was slightly higher than that of hybrid offspring ($F_1$, $F_H$). SDS-PAGE results showed that buffalo ${\alpha}_s$-casein had a slightly faster mobility than standard ${\alpha}_s$-casein; while buffalo ${\beta}$-casein showed a slightly slower mobility than standard ${\beta}$-casein. There is no clear differences in molecular weight of ${\alpha}_s$-, ${\beta}$-, and ${\kappa}$-casein among Murrah, $F_1$ and $F_H$.

The Evolution of Preferred Orientation and Morphology of NiO Thin Films under Variation of Plasma Source and RF Power (Plasma source와 RF power에 따른 NiO박막의 우선배향성 및 표면형상)

  • Hyunwook Ryu;Park, Jinseong
    • Proceedings of the Materials Research Society of Korea Conference
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    • 2003.11a
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    • pp.121-121
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    • 2003
  • NiO thin films are very attractive for use as an antiferromagnetic layer, p-type transparent conducting films, in electrochromic devices and functional sensor layer for chemical sensors, due to their excellent chemical stability, as well as optical, electrical and magnetic properties. In addition, (100)- and (111)-oriented NiO films can be used as buffer layers on which to deposit other oriented oxide films, such as c-axis-oriented perovskite-type ferromagnetic films and superconducting films, because of the similarity in symmetry of oxygen ion lattice and lattice constants between the NiO films and the oriented oxide films. Thus, controlling the crystallographic orientation and surface roughness of the NiO films for a buffer layer are very important.

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Effect of Bicarbonate and Phosphate Buffer Treatments on the Structure and Thermal Stability of Spent Layer Meat (중 탄산 및 인산염 완층액 처리가 노계육의 조직구조 및 열안정성에 미치는 영향)

  • Yi, Song-Sop;Mast, Morris G.
    • Korean Journal of Food Science and Technology
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    • v.23 no.6
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    • pp.695-701
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    • 1991
  • Spent layer breast meat and leg meat samples washed with 0.05 M sodium bicarbonate solution and 0.04 M phosphate buffer(pH 8.3) showed decreases in heat denaturation temperature indicating the destabilization of myofibrillar proteins. The destabilization was attributed to the solubilization of 95 Kdalton and 55 kdalton proteins from the myofibrils observed in gel-electrophoretograms. Transmission electron microscopy further indicated the breakage of Z-lines.

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Analysis on the Effectiveness of the Filter Buffer for Low Power NAND Flash Memory (저전력 NAND 플래시 메모리를 위한 필터 버퍼의 효율성 분석)

  • Jung, Bo-Sung;Lee, Jung-Hoon
    • IEMEK Journal of Embedded Systems and Applications
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    • v.7 no.4
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    • pp.201-207
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    • 2012
  • Currently, NAND Flash memory has been widely used in consumer storage devices due to its non-volatility, stability, economical feasibility, low power usage, durability, and high density. However, a high capacity of NAND flash memory causes the high power consumption and the low performance. In the convention memory research, a hierarchical filter mechanism can archive an effective performance improvement in terms of the power consumption. In order to attain the best filter structure for NAND flash memory, we selected a direct-mapped filter, a victim filter, a fully associative filter and a 4-way set associative filter for comparison in the performance analysis. According to the results of the simulation, the fully associative filter buffer with a 128byte fetching size can obtain the bet performance compared to another filter structures, and it can reduce the energy*delay product(EDP) by about 93% compared to the conventional NAND Flash memory.

화학적 특성이 다른 두 토양에서 EK-Fenton 공정 적용 시에 $H_2O_2$의 거동과 phenanthrene의 처리특성

  • 김정환;이군택;한상재;김수삼
    • Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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    • 2003.09a
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    • pp.128-131
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    • 2003
  • To clarify the effect of soil property on the EK-Fenton remediation of the soil contaminated with phenanthrene, this research had been conducted. In the experiments using EPK kaolinite, the $H_2O$$_2$ stability and effect of phenanthrene treatment improved more than that in the experiments using Hadong clayey soil. The results signify that Fe oxide content and acid buffer capacity significantly affected the fate of $H_2O$$_2$ and phenanthrene during the EK-Fenton process.

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Drug-Release Behavior of Polymeric Prodrugs of Ibuprofen with PEG and Its Derivatives as Polymeric Carriers

  • Lee, Chao-Woo
    • Macromolecular Research
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    • v.12 no.1
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    • pp.71-77
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    • 2004
  • We have synthesized various types of poly(ethylene glycol) (PEG)-ibuprofen conjugates by nucleophilic substitution of bromo-terminated PEG with ibuprofen-Cs salt. The conversion of the terminal hydroxyl groups to bromo-termini was quantitative, as was the drug conjugation process, which suggests that the present synthetic method is very useful for the preparation of PEG-based prodrugs from pharmaceuticals having carboxyl functionalities. The drug-release behavior of the prodrugs was examined in both phosphate buffer (PBS, pH 7.4) and rat plasma. From the drug-release behavior in PBS, we determined that each prodrug has high storage stability. The drug-release rate was observed to be much faster in rat plasma than in buffer solution as a result of the acceleration effect provided by enzymes present in the plasma. The drug-release rate in rat plasma depends on the degree of molecular aggregation of the prodrugs, which can be changed effectively by the nature of their spacer groups or by the use of Pluronic as the polymer carrier.

Comparison of the Characteristics of Alcohol-Oxidase by the Various Forms (여러 가지 형태에 따른 Alcohol-Oxidase의 특성 비교)

  • 이명숙
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.22 no.6
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    • pp.797-802
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    • 1993
  • The properties of the alcohol-oxidase from yeasts assimilating of methanol(Hansenula polymorpha CBS 4732, Pichia pastoris CBS 2612 and Candida boidinii CBS 8106) as free(cellules, purified enzymes) and immobilized forms(immobilized cellules, immobilized enzymes) were investigated. Immobilization enhanced the activity and stability of alcohol-oxidase to a certain degree. The optimum temperature of the immobilized alcohol-oxidase was lower than those of the free forms. The pH / activi쇼 profiles of alcohol-oxidase did not change by immobilization, but changed by the microorganisms. When the immobilized cellules were stocked at 4$^{\circ}C$ in 10mM potassium phosphate buffer(pH 7.5 or 8.0), alcohol-oxidase was more stable than those were stocked in potassium phosphate buffer containing 0.65M sucrose. The immobilization modifies the conditions of oxidation on the various substrates. alcohol-oxidase in immobilized forms showed some with higher Km value for methanol than that in free ones.

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Dissolution and Stability Enhancements of Trimethoprim by ${\beta}-Cyclodextrin$ Polymer Inclusion Complexation (트리메토프림과 ${\beta}$-시클로덱스트린 고분자 간의 포접복합체 형성에 의한 용출 및 안정성 향상)

  • Kim, Hyung-Tae;Park, Kyung-Ock;Seo, Seong-Hoon
    • Journal of Pharmaceutical Investigation
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    • v.22 no.2
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    • pp.105-113
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    • 1992
  • To improve the solubility and dissolution rate of trimethoprim (TMP), which is slightly soluble drug, its inclusion complexes were prepared and studied in this experiment. Inclusion complexes of TMP with ${\beta}-cyclodextrin$ and ${\beta}-cyclodextrin$ polymer (CDPS) were prepared according to Fenyvesi method. These were compared with TMP and its physical mixture with CDPS. Water, diluted hydrochloric acid and phosphate buffer solution were used as dissolution media. And accelerated stability test was studied at $50,\;70\;and \;80^{\circ}C$. It was found that solubility and dissolution rate of inclusion complexes were increased in water. Especially, the solubility and dissolution rate of TMP was found to be markedly increased by inclusion complexation with CDPS. In stability test, ${\beta}-cyclodextrin$ inclusion complexes were more or less stable than TMP alone. This tendency was not led in CDPS. Consequently, CDPS was useful in increasing dissolution rate and stability of TMP.

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How Vulnerable is Indonesia's Financial System Stability to External Shock?

  • Pranata, Nika;Nurzanah, Nurzanah
    • The Journal of Asian Finance, Economics and Business
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    • v.4 no.2
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    • pp.5-17
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    • 2017
  • The main objective of the study is to measure the vulnerability of Indonesia's financial system stability in response to external shocks, including from regional economies namely three biggest Indonesia major trading partners (China, the U.S and Japan) and other external factors (oil price and the federal funds rate). Using Autoregressive Distributed Lag (ARDL) model and Orthogonalized Impulse Response Function (OIRF) with quarterly data over the period Q4 2002 - Q1 2016, results confirm that, 1) oil price response has the largest effect to Indonesia financial stability system and the effect period is the longest compared to others, represented by NPL and IHSG; 2) among those three economies, only China's economic growth has significantly positive effect to Indonesia financial stability system. Based on the findings it is better for the authorities to: 1) Diversify international trade commodities by decreasing share of oil, gas, and mining export and boosting other potential sectors such as manufacture, and fisheries; 2) Ensure the survival of Indonesia large coal exporter companies without neglecting burden of national budget; and 3) Create buffer for demand shock from specific countries by diversifying and increasing share of trading from other countries particularly from ASEAN member states.