• Nutritional Sciences
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• v.1 no.1
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• pp.22-28
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• 1998

Plasma concentrations of Vitamins E and A were measured in 15 non-insulin dependent Korean female subjects and 15 age-matched normal subjects using reversed-phase high-performance liquid chromatography. No differences were found in plasma Vitamin E concentrations between the 2 groups. Plasma Vitamin A concentrations were higher in subjects with non-insulin dependent diabetes melitus (NIDDM). The effects were evaluated of 4 weeks of daily supplementation of 400 mg Vitamin E on plasma levels of these two vitamins. In addition, the effects were observed for Vitamin E supplementation on oxidative stress and immune-related compound productions in non-insulin dependent diabetic patients and control subjects. After treatment with Vitamin E, plasma Vitamin E concentrations were significantly elevated in both groups. Basal plasma thiobarbituric acid reactive substances (TBABS) were identical, and a decreased level of TBARS caused by Vitamin E was observed only in the diabetic group (0.02739$\pm$0.0024 versus 0.01814$\pm$0.0008 nmols malondialdehyde equivalents/dl plasma ; p<0.05). The basal and after-treatment levels of immunoglobulins A, G, M were identical in control and diabetic groups, indicating that Vitamin E did not appear to alter gross humoral responses in this study. However, elevation of Complement 3 ($C_3$) was noticed due to Vitamin E supplementation, revealing a possible effect of vitamin E on one aspect of humoral immunity, Furthermore, an increase in prostaglandin E_2 ($PGE_2$) levels in diabetic patients was normalized by Vitamin E supplementation. This suggests indirectly that the depressed cell-mediated response due to elevated $PGE_2$ could be normalized. For the definitive antioxidant intake recommendations for prevention and treatment of adverse effects of non-insulin dependent diabetes, evidence from intervention trials like this study should be collected. The present data suggests that Vitamin E may oxen some protective effects against oxidative damage and might have beneficial effects of partial immune-stimulation.

• Analytical Science and Technology
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• v.26 no.5
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• pp.307-314
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• 2013

Selenium exists in various forms of chemical species. The activity and bioavailability is strongly dependent on its chemical form and concentration. Consequently the information on each selenium species and its concentration must be exactly determined for the food we take in. In this study, selenium species in seafood were separated and quantified by RP (reversed phase) HPLC (high performance liquid chromatography) coupled with ICP-MS (inductively coupled plasma mass spectrometry) using post-column isotope dilution. $^{79}Br$, which interferes on $^{80}Se$, has mostly been removed by solid phase extraction and then mathematical correction has been applied for the more accurate correction. The experimental result for CRM (certified reference material) DOLT-4 agreed well with the certified value but each selenium species could not be compared. SeCys (selenocysteine) and SeMet (selenomethionine) were the major species detected in seafood such as belt fish, spanish mackerel, and squid that have been serving as Korean diet. The concentrations found in Korean sea food for SeCys and SeMet were in the range of 0-661.6 mg/kg and 137.3-462.7 mg/kg, respectively.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.6 no.2
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• pp.229-237
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• 1996

The superconducting phase, $YBa_{2}Cu_{3}O_{x}$ (YBCO), was in-situ deposited on the single crystal MgO substrates, using an aerosol decomposition process in a cold plasma reactor. The solubility and decomposition temperature of the chemical precursors, and the vapor pressures of the solvents, were determined to be the factors crucial to achieving a stoichiometric, crystalline YBCO phase. The deposition parameters for the YBCO phase were 0.3 to 2.7 kPa for the oxygen partial pressure and $800^{\circ}C$ to $940^{\circ}C$ for the substrate temperature. The optimum deposition conditions for the YBCO phase were observed along the CuO decomposition line.

• Journal of Ginseng Research
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• v.37 no.1
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• pp.135-141
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• 2013

A rapid, sensitive and selective analytical method was developed and validated for the determination of compound K, a major intestinal bacterial metabolite of ginsenosides in human plasma. Liquid-liquid extraction was used for sample preparation and analysis, followed by liquid chromatography tandem spectrometric analysis and an electrospray-ionization interface. Compound K was analyzed on a Phenomenex Luna C18 column ($100{\times}2.00$ mm, 3 ${\mu}m$) with the mobile phase run isocratically with 10 mM ammonium acetate-methanol-acetonitrile (5:47.5:47.5, v/v/v) at a flow rate of 0.5 mL/min. The method was validated for accuracy (relative error <12.63%), precision (coefficient of variation <9.14%), linearity, and recovery. The assay was linear over the entire range of calibration standards i.e., a concentration range of 1 ng/mL to 1,000 ng/mL ($r^2$ >0.9968). The recoveries of compound K after liquid-liquid extraction at 1, 2, 400, and 800 ng/mL were $106.00{\pm}0.08%$, $103.50{\pm}0.19%$, $111.45{\pm}5.21%$, and $89.62{\pm}34.46%$ for intra-day and $85.40{\pm}0.08%$, $94.50{\pm}0.09%$, $112.50{\pm}5.21%$, and $95.87{\pm}34.46%$ for inter-day, respectively. The lower limit of quantification of the analytical method of compound K was 1 ng/mL in human plasma. The developed method was successfully applied to a pharmacokinetic study of compound K after oral administration in ten of healthy human subjects.

• Journal of Pharmaceutical Investigation
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• v.35 no.4
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• pp.287-293
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• 2005

The purpose of the present study was to evaluate the bioequivalence of two glimepiride tablets, Amaryl tablet (Handok & Aventis Korea, reference drug) and Mepiril tablet (Myungmoon Pharm. Co., Ltd., Korea, test drug), according to the guidelines of Korea Food and Drug Administration (KFDA). After adding an internal standard (glibenclamide) to human plasma, plasma samples were extracted using 1mL of methyl tertiary butyl ether. Compounds extracted were analyzed by reverse-phase HPLC with multiple reaction monitoring (MRM) mode analyte detection. This method for determination glimepiride proved accurate and reproducible, with a limit of quantitation of 2 ng/mL in human plasma. Twenty-four healthy male Korean volunteers received each medicine at the glimepiride dose of 2 mg in a $2{\times}2$ crossover study. There was a one-week washout period between the doses. Plasma concentrations of glimepiride were monitored by a LC-MS/MS for over a period of 12 hr after the administration. $AUC_t$ (the area under the plasma concentration-time curve from time zero to 12 hr) was calculated by the linear trapezoidal rule method. $C_{max}$ (maximum plasma drug concentration) and $T_{max}$ (time to reach $C_{max}$) were compiled from the plasma concentration-time data. Analysis of variance was carried out using logarithmically transformed $AUC_t$ and $C_{max}$. No significant sequence effect was found for all of the bioavailability parameters indicating that the crossover design was properly performed. The 90% confidence intervals of the $AUC_t$ ratio and the $C_{max}$ ratio for Amaryl/Mepiril were log 0.9583-log 1.1357 and log 1.0570-log 1.2376, respectively. These values were within the acceptable bioequivalence intervals of log 0.80-log 1.25. Taken together, our study demonstrated the bioequivalence of Amaryl and Mepiril with respect to the rate and extent of absorption.

• YAKHAK HOEJI
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• v.25 no.3
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• pp.101-108
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• 1981

Quantitative determination of capsaicin in biological fluid was investigated. The pharmacokinetic study of capsaicin in rabbits was performed by high-pressure liquid chromatography, equipped with a microparticulate reversed-phase column and a fixed wavelength detector. Elution was carried out using methanolwater(70:30). It allows the quantitative determination at 8-400 ng level. When single dose of capsaicin(4mg/kg) was given to rabbits intravenously, the elimination phase was extremely short with average half-life to 17.35 minute. Urine excretion of capsaicin itself during first 2 hours after intravenous administration (4mg/kg) was 0.004-0.04% of the administered amount. The maximum plasma concentration of capsaicin after oral administration (300mg/kg) was $4{\times}10^{-7}$g/ml at 40 minutes. The $LD_{50}$ of capsaicin in mouse was 0.40mg/kg (i.v.) and 47.2 mg/kg (p.o.) which was determined by Litchfield and Wilcoxon's method, suggesting that the gastrointestinal absorption of capsaicin is poor.

• Korean Journal of Materials Research
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• v.19 no.9
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• pp.504-509
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• 2009

The Zr-based bulk metallic glass matrix composites of a mixture of gas-atomized metallic glass powders and Fe-based nanostructured powders were fabricated by spark plasma sintering. The Fe-based nanostructured powders adopted for the enhancement of plasticity were well distributed in the matrix after consolidation, and the matrix remains as a fully amorphous phase. The successful consolidation of metallic glass matrix composite with high density was attributed to viscous flow in the supercooled liquid state during spark plasma sintering. Unlike other amorphous matrix composites, in which improved ductility could be obtained at the expense of their strength, the developed composite exhibited improvement both in strength and ductility. The ductility improvement in the composite was considered to be due to the formation of multiple shear bands under the presence of the Fe-based nanostructured particles.

• Journal of Pharmaceutical Investigation
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• v.17 no.2
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• pp.55-60
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• 1987

WR 2721 (S-2-(3-aminopropylaminoethylphosphorothioate) is a radioprotective drug that is now undergoing clinical trials in the United States and Japan. a liquid chromatographic electrochemical method for the determination of WR 2721 an WR 3689 [S-2-(3-methylaminopropylamino)ethylphorothioate] in human plasma was developed in this study. This method includes the use of a Hg/Au electrochemical detector and a cyano column for the direct measurement of WR 2721 and WR 3689 in plasma. An analog of WR 2721, WR 149846 was used as an internal standard. WR 2721 and WR 3689 could be well separated from the solvent front, with a mobile phase of acetonitrile-water (20:80), 0.1M acetic acid and 1.2 mM sodium octane sulfonate. This method was shown to be precise. Both intra-day and inter-day results were within 10% CV. Also, sample preparation was fairly simple. Since WR 2721 and WR 3689 were unstable at room temperature, it was essential to use an automatic sample processor with a refrigerator, especially for carrying out routine analyses.

• Journal of the Korean Ceramic Society
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• v.46 no.5
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• pp.467-471
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• 2009

Effects of boron and carbon on the densification and thermal decomposition of an AlN-SiC-$TiB_2$ system were investigated. $SiO_2$ was mostly removed by the addition of carbon, while $Al_2O_3$ formed $Al_4O_4C$ and promoted the densification of the systems above $1850^{\circ}C$. Rather porous specimens were obtained without the additives after hot pressing at $2100^{\circ}C$, while densification was mostly completed at $2000^{\circ}C$ by using the additives. The sintering temperature decreased further to $1950^{\circ}C$ by applying spark plasma sintering. The additives promoted the shrinkage of AlN by forming a liquid phase which was originated from the carbo- and boro-thermal reduction of $Al_2O_3$ and AlN.

• Korean Journal of Materials Research
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• v.24 no.7
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• pp.357-362
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• 2014

Thermal barrier coatings(TBCs) are being applied in many industrial fields such as thermal power generation, aviation and seasonal fields. $ZrO_2-Y_2O_3$(8%) thermal spray coating powders are commercially used as thermal-barrier coating materials to protect against oxidation and corrosion of heat-resistant alloys at elevated temperatures. Currently, $ZrO_2-Y_2O_3$(8%) thermal-spray powder is made using the industrial co-precipitation process, which is very complex and requires a lot of time. In this study, orthorhombic $ZrO_2$ and $Y_2O_3$ powders were fabricated by mechanical mixing, which is more economical than the co-precipitation process. A tetragonal, yttria-stabilized zirconia(YSZ) coating-layer was produced by plasma spraying, using orthorhombic $ZrO_2-Y_2O_3$(8%) powder. Our experimental results indicate that $ZrO_2-Y_2O_3$(8%) mixed powder can be used economically in industry because it is no longer necessary to make this powder by liquid and gas-phase methods.