• Title/Summary/Keyword: Ph.D.

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Determination and Ethylene Oxide(EO) Separation of Polysorbates by RP-HPLC (역상 HPLC에 의한 polysorbates의 산화에틸렌(EO) 분리 및 정량분석)

  • Lee, Yong-Hwa
    • Journal of the Korean Applied Science and Technology
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    • v.29 no.4
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    • pp.585-593
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    • 2012
  • The EO separation and quantitative determination of polysorbate 20, polysorbate 40, polysorbate 60 and polysorbate 80 was carried out by reversed phase HPLC. The water/acetonitrile was used for the mobile phase of gradient conditions. An YMC Pack Ph ($250mm{\times}4.6mm$ i.d., $5{\mu}m$) and Phenomenex C4 ($250mm{\times}4.6mm$ i.d., $5{\mu}m$) and the selected ELSD detector was applied. The analysis results of HPLC showed good linearity with correlation coefficient of $r^2$=0.997 in the rage of $180.2{\sim}980.5{\mu}g/mL$ and detection limit.

In vivo Study of the Renal Protective Effects of Capsosiphon fulvescens against Streptozotocin-induced Oxidative Stress (스트렙토조토신 유발 당뇨 쥐의 산화스트레스에 대한 매생이 추출물의 신장 보호 효과)

  • Nam, Mi-Hyun;Koo, Yun-Chang;Hong, Chung-Oui;Yang, Sung-Yong;Kim, Se-Wook;Jung, Hye-Lim;Lee, Hwa;Kim, Ji-Yeon;Han, Ah-Ram;Son, Won-Rak;Pyo, Min-Cheol;Lee, Kwang-Won
    • Korean Journal of Food Science and Technology
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    • v.46 no.5
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    • pp.641-647
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    • 2014
  • In this study, we evaluated the effect of Capsosiphon fulvescens extract (CFE) and its active compound, pheophorbide A (PhA), on diabetic kidney failure. Diabetes mellitus (DM) was induced by a single intraperitoneal injection of streptozotocin (STZ; 40 mg/kg body weight (BW)). After a week, the rats were orally administered CFE (4 and 20 mg/kg BW) or PhA (0.2 mg/kg BW) once a day for 9 weeks. After scarification, renal tissue samples were collected for biochemical and histochemical analyses. Our study showed that the treatment with CFE and PhA significantly decreased lipid peroxidation level and the activities of glutathione peroxidase and glutathione-S-transferase (p<0.05), but it increased glutathione level and the activities of glutathione reductase, superoxide dismutase, and catalase in the renal tissues (p<0.05). The CFE- and PhA-treated rats with DM showed improved histochemical appearance and decreased abnormal glycogen accumulation. Therefore, we suggest that PhA-containing CFE could exert renal protective effects against STZ-induced oxidative stress.

Kinetic Studies of the Solvolyses of 4-Nitrophenyl Phenyl Thiophosphorochloridate

  • Koh, Han-Joong;Kang, Suk-Jin
    • Bulletin of the Korean Chemical Society
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    • v.30 no.10
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    • pp.2413-2418
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    • 2009
  • Rates of solvolyses of 4-nitrophenyl phenyl thiophosphorochloridate (4-N$O_2$PhOP(S)(Cl)OPh, $\underline{1}$) in ethanol, methanol, and aqueous binary mixtures incorporating ethanol, methanol, acetone, and 2,2,2-trifluroethanol (TFE) are reported. Thermodynamic parameters were determined at several temperatures in three representative solvents. The extended Grunwald-Winstein equation was applied to 29 solvents and the correlation coefficient (R) showed 0.959. The sensitivities (l = 1.37 and m = 0.62) are similar to those obtained for diphenyl thiophosphorochloridate (($PhO)_2$PSCl, $\underline{2}$), diphenyl phosphorochloridate (($PhO)_2$POCl, $\underline{3}$), diphenyl phosphinic chloride ($Ph_2$POCl, $\underline{4}$), and diphenyl thiophosphinic chloride ($Ph_2$PSCl, $\underline{5}$). The solvolytic reaction mechanism of 4-nitrophenyl phenyl thiophosphorochloridate ($\underline{1}$) is suggested to be proceeded a $S_N$2 process as previously reported result. The activation enthalpies are shown as slightly low as ${\Delta}H^{\neq}\;=\;9.62\;to\;11.9\;kcal{\cdot}mol^{-1}$ and the activation entropies are shown as slightly high negative value as ${\Delta}S^{\neq}\;=\;-34.1\;to\;-44.9\;cal{\cdot}mol^{-1}{\cdot}K^{-1}$ compared to the expected $S_N$2 reaction mechanism. Kinetic solvent isotope effects are accord with a typical $S_N$2 mechanism as shown in the range of 2.41 in MeOH/ MeOD and 2.57 in $H_2O/D_2O$ solvent mixtures.

Comparative Analysis on the Effectiveness of Employment Subsidy for R&D Personnel and R&D Subsidy (연구인력 고용보조금 지원과 R&D자금 출연 지원의 효과성 비교 분석)

  • Noh, Meansun;Kim, Sukpil;Lee, Ki Jong
    • Journal of Technology Innovation
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    • v.21 no.3
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    • pp.73-94
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    • 2013
  • The prinary cause of the decreasing SME's competitiveness in technology is the intensifying human resource shortages. The government supports a part of labor costs for SMEs as a means of policy. There are two ways of supporting labor costs for R&D personnel. One is to hire R&D personnel first then support their partial labor costs. The other is to support labor costs first for R&D personnel in national R&D programs then hire R&D personnel. This study analyzes the effectiveness of two different ways by classifying sales, no. of employees, R&D expenditure, no. of researchers, and no. of MA/Ph.D. researchers. In terms of employing researchers with MA or Ph.D., the effectiveness on employment subsidy is significantly higher than that of R&D subsidy. Its effect has been relatively high in non-metropolitan areas and manufacturing industry.