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6${\beta}$-Bromopenicillanate로부터 6-(Carboxymethylthio) penicillanic Acid 유도체의 합성
최원식,이영행,이채호,Won-Sik Choi,Young-Haeng Lee,Chai-Ho Lee 대한화학회 1991 대한화학회지 Vol.35 No.5
6${\beta}$-bromopenicillanic acid(4a)와 p-nitrobenzylbromide, 3-bromophthalide, chloromethylpivalate 및 1-chlorodiethylcarbonate의 반응으로 6${\beta}$-bromopenicillanates(4b~4e)을 합성하였으며, 6${\beta}$-bromopenicillanic acid(4a)와 그의 ester(4b~4e)를 thioglycolic acid와 친핵성 치환반응시켜 새로운 $\beta$-lactam계 화합물인 6-(carboxymethylthio)penicillanic acid(5a)와 그의 ester(5b~5e)를 얻었다. Reaction of 6${\beta}$-bromopenicillanic acid(4a) with p-nitrobenzylbromide, 3-bromophthalide, chloromethylpivalate and 1-chlorodiethylcarbonate afforded 6${\beta}$-bromopenicillanates(4b~4e). New ${\beta}$-lactam compound, 6-(carboxymethylthio)penicillanic acid(5a) and the other esters(5b~5e) were prepared by nucleophilic substitution reaction of 6${\beta}$-bromopenicillanic acid(4a) and the other esters(4b~4e) with thioglycolic acid.
한국산 옻나무로부터 추출.분리한 생리활성 물질들의 항산화 효과 및 세포독성
최원식,김동길,이영행,김장억,이성은,Choi, Won-Sik,Kim, Dong-Kil,Lee, Young-Haeng,Kim, Jang-Eok,Lee, Sung-Eun 한국응용생명화학회 2002 한국농화학회지 Vol.45 No.3
한국산 옻나무의 메탄올추출물과 유기용매 분획의 항산화 효과를 조사하였다. 항산화 효과는 수소공여 억제능, 과산화지질 형성 억제능, xanthine oxidase저해 활성과 아질산염 소거능으로 측정한 결과, ethyl acetate 분획이 가장 뛰어난 효과를 나타내었다. 이 분획의 생리활성 물질을 분리하기 위하여, rotatory locular counter current chromatography(RLCCC), Sephadex LH-20 column chromatograpy와 HPLC등의 방법을 사용하여, 1,2,3-trihydroxybenzene, methyl 3,4,5-trihydroxybenzoat와 3,4,5-trihydroxybenzoic acid를 분리하였다. 이중 methyl 3,4,5-trihydroxybenzoate는 butylated hydroxyanisole(BHA)이나 butylated hydroxytoluene(BHT)보다도 강한 항산화 효과를 나타내었다. 그러나 세포독성 실험에서는 이들 물질들이 암세포주에 대하여 활성이 높지 않았다. 이상의 결과로 methyl 3,4,5-trihydroxybenzoate은 뛰어난 항산화 효과를 지닌 식품첨가물로서의 이용 가능성을 제시할 수 있다. Antioxidative activities of solvent fractions obtained from Korean Rhus vernicifera, being used in food industry and as a traditional medicine, were examined by the methods of DPPH scavenging activity, inhibitory effect on autooxidation of linoleic acid, nitrite scavenging activity and the inhibitory effect on xanthine oxidase activity. Ethyl acetate fraction showed potent antioxidative activities. Three compounds were isolated from the ethyl acetate fraction by rotatory locular counter current chromatography (RLCCC), Sephadex LH-20 column chromatography and HPLC. The isolated compounds were 1,2,3-trihydroxybezene, methyl 3,4,5-trihydroxybenzoate and 3,4,5-trihydroxybenzoic acid determined by GC/MS and, $^1H$ and $^{13}C$ NMR. Among the isolated compounds, methyl 3,4,5-trihydroxybenzoate showed the strongest antioxidative activity than artificial antioxidants, BHA and BHT in various methods. However, these isolated compounds did not show cytotoxicity effects on the human cancer cell lines. Therefore, we may suggest that methyl 3,4,5-trihydroxybenzoate can be used as a food additive possessing the potent antioxidative activity.
Tribological Characteristics in $40{\mu}m$ Dimple Pattern for Hexagonal Array
최원식,채영훈,Choi, Won-Sik,Chae, Young-Hoon,Umehara, Noritsugu Korean Tribology Society 2009 한국트라이볼로지학회지 (Tribol. Lubr.) Vol.17 No.5
본 연구에서는 pin-on-disk 마찰 시험기를 통하여 Hexagonal 배열 $40{\mu}m$ Dimple 패턴의 효과를 실험하였다. 마찰 실험은 미끄럼 속도가 $0.06{\sim}0.34m/s$로 하였으며 마찰하중은 $20{\sim}100\;N$의 범위로 하였고, Dimple의 밀도는 $10{\sim}25%$의 범위로 제작하여 실험을 행하였다. 일반적으로 속도가 증가하고 하중이 감소할수록 마찰계수는 감소하는 경향을 나타내었으며, Dimple에 의한 마찰저감 효과는 속도가 $0.14{\sim}0.26m/s$의 범위에서 나타났다. $40{\mu}m$ Hexagonal 배열 Dimple 패턴의 마찰 특성에서는 밀도가 12.5%에서 가장 좋은 경향을 나타내었다.
선박엔진의 Supply Unit용 SNCM420H의 절삭특성
최원식,성봉수,강창원,문희준,권주리,Choi, Won-Sik,Sung, Bong-Soo,Kang, Chang-Won,Mun, Hee-Joon,Kwon, Ju-Ri 한국생산제조학회 2010 한국생산제조학회지 Vol.25 No.5
SNCM420 steel is one of the cam shaft materials which are used in the supply unit for ship engine cam shaft. In this study the assessment of cutting behavior was conducted for the SNCM 420 steel and SM45C steel with various cutting conditions as depth of cut 0.5, 1.0, 1.5, 2.0mm and feed rate 0.1~0.3m/rev. The controlled chip was produced in feed rate 0.2, depth of cut 1.0 for SNCM420 and feed rate 0.2, depth of cut 2.0 for SM45C. There is no difference cutting force between SM45C and SNCM420 steels.
Friction Characteristics of CNx Coated Dimple Pattern with Hexagonal Array
최원식,Choi, Won-Sik,Umehara, Noritsugu Korean Tribology Society 2011 한국윤활학회지(윤활학회지) Vol.15 No.3
In this study, we examined the friction characteristics of a dimple pattern on a carbon nitride coating. The study was conducted with a hexagonal array 40 ${\mu}m$ dimple pattern on a steel bearing containing a CNx coating. The area density of the dimple patterns were varied between 5% and 25%, the speed was varied from 0.06-0.26 m/s, and the load was varied between 20-100N. In general, we found that as the velocity increased, the friction coefficient increased. Furthermore, the friction coefficient was lowest at a load of 40N. The friction coefficient of the non-coated specimen was 0.025-0.15; on the other hand, the friction coefficient of the coated specimen was 0.002-0.02. Thus, we determined that the coated materials could reduce the friction coefficient by a factor of 7.5.
최원식(Won-Sik Choi),박나람(Na-Ram Park),이창주(Chang-Ju Lee) 한국산학기술학회 2014 한국산학기술학회 학술대회 Vol.- No.-
본 논문에서는 PVC의 재료의 절삭유의 유무에 따른 드릴링 특성 및 칩의 관찰을 통하여 최적의 재 료 가공방법을 알아보고자 한다.
Protective Effects of HEAC and its Primary Active Compound on HCl-ethanol Induced Gastritis in Rats
최원식(Choi, Won-Sik),장도연(Jang, Do-Yoen),이경락(Lee, Gyung-Rak),김승한(Kim, Seung-Han) 한국산학기술학회 2012 한국산학기술학회논문지 Vol.13 No.4
노루궁뎅이 버섯 균사체를 인진쑥 배지에 배양시킨 배양물(HEAC)을 여러 농도의 에탄올-물의 용액으로 추출하고, 쥐에서 위염 유발시약(0.15 M 염산-에탄올 용액)에 의한 위점막 손상에 대하여 추출물들의 위염 억제효과실험을 실시하였 다. 그 중 80% 에탄올 추출물은 위염에 대하여 67.7%로 우수한 억제효과를 나타내었다. 용매별 분획으로 HEAC의 80% 에탄올 추출물을 노르말 헥산, 염화메틸렌, 초산에틸, 노르말 부탄올과 증류수를 이용하여 5가지 분획으로 분리하였다. 그 결과, 노르말 헥산과 염화메틸렌 분획들이 위염에 대하여 우수한 억제효과를 나타내었다. 이에 따라 염화메틸렌 추출물 에 대하여 GC/MS, HPLC, IR and NMR(1H, 13C)을 이용하여 생리활성 주성분의 구조를 확인한 결과 ethyl linoleate임을 확인하였다. 또한, HEAC의 80% 에탄올 추출물과 ethyl linoleate의 ED50값이 각각 22.6과 6.4 mg/kg을 나타내어 대조약제 인 stillen (44.2 mg/kg)과 selbex (46.5 mg/kg) 보다 우수한 억제효과가 있음을 확인하였다. 그러므로, HEAC의 80% 에탄올 추출물과 ethyl linoleate는 염산-에탄올에 의하여 유발된 위염에 대하여 우수한 억제효과를 가지고 있으며, 새로운 위염,위 궤양 치료제로 개발될 수 있을 것으로 기대된다. The purpose of this study is to evaluate the gastric mucosal damage effect by Hericium erinaceus cultibated with Artemisia capillaris (HEAC) with 0.15 M HCl in ethanol in rats. Among them, 80% ethanol extract showed potent inhibitory effect (67.7%) on gastritis. Using solvent fractionation, 80% ethanol extract of HEAC was separated into five fractions with n-hexane, methylene chloride, ethyl acetate, n-butanol and water. As a result, fractions obtained with methylene chloride exhibited strong inhibitory effects on gastritis. With this result, the methylene chloride extract was analyzed by GC/MS, HPLC, IR and NMR(1H, 13C) to identify primary active components and the main component in the extract was identified as ethyl linoleate. The effective does (ED50) values of 80% ethanol extract of HEAC and ethyl linoleate showed 22.6 and 6.4 mg/kg, respectively and these values were higher than those of stillen (44.2 mg/kg) and selbex (46.5 mg/kg). Therefore, the administration of 80% ethanol extract of HEAC and ethyl linoleate have a strong protective effect agasint the gastritis induced by HCl-ethanol and may be promising new drug for treating gastritis and gastric ulcer.