• Title/Summary/Keyword: Kyung Keun

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Kinetics and Mechanism of the Aminolysis of O-Methyl-S-Phenylthiocarbonates in Methanol

  • Song, Ho-Bong;Choi, Moon-Ho;Koo, In-Sun;Oh, Hyuck-Keun;Lee, Ik-choon
    • Bulletin of the Korean Chemical Society
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    • v.24 no.1
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    • pp.91-94
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    • 2003
  • Kinetic studies of the reaction of O-methyl-S-phenylthiocarbonates with benzylamines in methanol at 45.0 ℃ have been carried out. The reaction proceeds by a stepwise mechanism in which the rate-determining step is the breakdown of the zwitterionic tetrahedral intermediate, $T^{\pm}$, with a hydrogen-bonded four-center type transition state (TS). These mechanistic conclusions are drawn based on (ⅰ) the large magnitude of ${\rho}_X\;and\;{\rho}_Z$, (ⅱ) the normal kinetic isotope effects $(k_H/k_D\;>\;1.0)$ involving deuterated benzylamine nucleophiles, (ⅲ) the positive sign of ${\rho}_{XZ}$ and the larger magnitude of ${\rho}_{XZ}$ than that for normal $S_N2$ processes, and lastly (ⅳ) adherence to the reactivity-selectivity principle (RSP) in all cases.

Spectroscopic Study of the Ã1A" - X~1A' System of CHBr

  • Shin, Seung-Keun;Park, Seung-Min
    • Bulletin of the Korean Chemical Society
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    • v.32 no.3
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    • pp.905-908
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    • 2011
  • We report fluorescence excitation and emission spectra of the CHBr molecule generated via pyrolysis of $CH_3Br$ in a molecular beam experiment. The 193 nm attenuation cross sections were estimated from the reduction of the CHBr signal as a function of the excimer laser fluence. The derived 193 nm absorption cross section for CHBr [$(3.24{\pm}0.59){\times}10^{-17}\;cm^2$] is slightly higher than the absorption cross section previously determined for CHCl [$(2.6{\pm}0.8){\times}10^{-17}\;cm^2$], but the difference is within the estimated uncertainties in the measured cross section.

The CHP system efficiency (열병합발전시스템의 효율)

  • Lee, Song-Keun;Choi, Jun-Young;Jang, Gil-Soo;Mok, Hyung-Soo;Son, Sung-Yong;Yoon, Yong-Tae;Son, Kwang-M.;Hon, Jun-Hee
    • Proceedings of the KIEE Conference
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    • 2007.07a
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    • pp.784-785
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    • 2007
  • 열병합발전시스템의 경제성은 배열을 회수하여 사용함으로써 전기를 생산함과 동시에 열을 사용하여 에너지의 효율을 높이는데 있다. 그렇지만 열과 전기의 사용이 동시에 이루어지지 않을 경우에는 열병합발전시스템의 장점이 사라지게 된다. 이 논문에서는 열병합발전시스템의 효율을 계산하는 방법을 제시하여 열병합발전시스템을 도입하는 단계에서 좀 더 체계적인 방법으로 분석할 수 있는 방법을 제시하였다.

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Gram-Positive Bacteria Specific Properties of Silybin Derived from Silybum marianum

  • Lee, Dong-Gun;Kim, Hyung-Keun;Park, Yoon-Kyung;Park, Seong-Cheol;Woo, Eun-Rhan;Jeong, Hye-Gwang;Hahm, Kyung-Soo
    • Archives of Pharmacal Research
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    • v.26 no.8
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    • pp.597-600
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    • 2003
  • Silybin has a potent antibacterial activity, more potent than silymarin II, against gram-positive bacteria without hemolytic activity, whereas it has no antimicrobial activity against gram-negative bacteria or fungi. The mode of action of silybin against the gram-positive bacterial cell was examined by investigating the change in plasma membrane dynamics of bacterial cells using 1 ,6-diphenyl-1,3,5-hextriene (DPH) as a membrane probe and by assessing the inhibition of macromolecular synthesis using radiolabeled incorporation assay. The results showed that silybin inhibited RNA and protein synthesis on gram-positive bacteria.

Phytochemical Constituents from Diodia teres

  • Lee, Jae-Hyeok;Ku, Chung-Hwan;Baek, Nam-In;Kim, Sung-Hoon;Park, Hee-Wook;Kim, Dae-Keun
    • Archives of Pharmacal Research
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    • v.27 no.1
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    • pp.40-43
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    • 2004
  • All ten compounds were isolated from the methanolic extract of the whole plants of Diodia teres through repeated silica gel and Sephadex LH-20 column chromatography. Their chemical structures were elucidated as three iridoid glycosides, asperuloside, geniposidic acid and asperulosidic acid, a coumarin glycoside, scopolin, and six flavonoids, rutin, kaempferol-3-0-rutinoside, quercitrin, astragalin, isoquercitrin and quercetin by spectroscopic analysis.

Typha orientalis inhibits inflammatory cytokine expression through suppression of ERK phosphorylation in HMC-1 cells

  • Choi, In-Young;Na, Ho-Jeong;Um, Jae-Young;Kim, Hyung-Min;Hong, Seung-Heon;Sim, Kuk-Jin;Song, Bong-Keun;Nam, Gi-Hye;Choung, Se-Young;Jeong, Hyun-Ja
    • Advances in Traditional Medicine
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    • v.10 no.1
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    • pp.7-12
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    • 2010
  • Typha orientalis' stem (TOS) is traditionally used as an herbal medicine for difficulty in urination, galactophoritis purulenta, whooping cough, and allergic dermatitis. However, its effect in experimental models remains unknown. Here, we report the effect of TOS on the phorbol 12-myristate 13-acetate (PMA) plus calcium ionophore A23187-induced inflammatory cytokine production and extracellular signal-regulated kinase (ERK) activation in the human mast cell line, HMC-1. TOS inhibited PMA plus A23187-induced cytokines such as tumor necrosis factor-alpha (TNF-$\alpha$) and interleukin (IL)-6. Maximal inhibition rate of TNF-$\alpha$ and IL-6 production by TOS (1 mg/ml) was about 44.02%, and 45.20%, respectively (P < 0.05). In addition, TOS inhibited the expression of TNF-$\alpha$ and IL-6 mRNA under the same condition. Moreover, TOS partially blocked PMA plus A23187-induced ERK phosphorylation. These results suggested TOS could inhibit the cytokine production through blocking of ERK activity.

Clinical Assessment of 28 Patients with Cough Treated with Herbal Steam Therapy (훈증요법을 병행한 기침환자 28명에 대한 임상적 평가)

  • Kim, Kwan Il;Lee, Hee Beom;Park, Eui Keun;Choi, Yeon Jung;Kim, Dong Hyun;Jung, Hee Jae;Jung, Sung Ki
    • Journal of Physiology & Pathology in Korean Medicine
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    • v.27 no.5
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    • pp.660-666
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    • 2013
  • The purpose of this study was to investigate the clinical effects of herbal steam therapy on cough. Twenty-eight patients with cough who had treated with herbal steam therapy(chungsang, chungpae) between 3rd of January and 30th of April, 2013 were analyzed. The effects were evaluated the severity and frequency of cough as the modified questionnaire, severity of discomfort using visual analogue scale(VAS), and the patients' subjective satisfaction. Eighteen patients who had been treated herbal steam therapy over 3 times were analyzed improvements before and after therapy. Chungsang and Chungpae steam therapies significantly decreased the severity and frequency of cough. VAS scores also decreased from $7.78{\pm}0.878$ to $4.39{\pm}2.033$. Patients were satisfied with herbal steam therapy. Chungsang and Chungpae steam therapies seem to be effective in the treatment of cough. Further studies with a large number of cases will be needed in the future.

A Study on the Prevalence and Risk Factors of the Metabolic Syndrome according to Sasang Constitution (사상체질에 따른 대사증후군의 유병률과 위험인자에 대한 연구)

  • Lee Tae-Gyu;Hwang Min-Woo;Lee Soo-Kyung;Choe Bong-Keun;Go Byeong-Hui;Song Il-Byung
    • The Journal of Korean Medicine
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    • v.27 no.2 s.66
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    • pp.14-22
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    • 2006
  • Objectives : The purpose of this study was to find the prevalences and risk factors of the metabolic syndrome according to Sasang constitution. Methods : The medical records of 364 subjects who had taken health examinations and diagnosis of Sasang constitution from January to June of 2003 at a health examination center of a hospital in Seoul were reviewed. The prevalences and the risk factors of the metabolic syndrome according to Sasang constitution were compared and analyzed. Results : 1) Among the 364 subjects, 88 (24.2%) were Soeumin, 101 (27.7%) were Soyangin, and 175 (48.1%) were Taeumin. 2) The prevalences of high WC, high TG, low HDL-c, high BP and high FBS of Taeumin were significantly higher than those of the other constitutions (p-value < 0.05). 3) The prevalence of the metabolic syndrome of Taeumin, Soyangin, and Soeumin were 46.3%, 16.8% and 9.1% respectively. The rates were significantly different according to Sasang constitution (p-value < 0.001). 4) Taeumin had higher risk of high WC than Soeumin (adjusted OR : 3.83, 95% CI : 1.19-12.29) and higher risk of high FBS than Soeumin (adjusted OR: 5.93,95% CI : 1.11-31.77). 5) Taeumin had higher risk of the metabolic syndrome than Soeumin (adjusted OR : 3.40, 95% CI : 1.25-9.23). Conclusions : There were significant differences in the prevalence of metabolic syndrome according to Sasang constitution. Sasang constitution was identified as an independent risk factor of metabolic syndrome.

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