• 한국응용과학기술학회지
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• 제17권3호
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• pp.167-173
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• 2000

The process variables for the manufacture of translucent microemulsion prepared with 2-octyl dodecanol, 12-hydroxy stearic acid cholesteryl , POE(40)HCO and 1,3-butandiol were examined initially (primary emulsion) and following aging for three months. The techniques empolyed in this study were particle size, turbidity, interfacial tension and microfluidizer. Particle size analysis and turbidity measurement to evaluate the emulsion stability were used. It was concluded that the process of the emulsification was an important indicator of the stability of the translucent microemulsion. From the particle size and and turbidity measurement of translucent microemulsion, adding the surfactant to the oil phase before the emulsification was found to be the most important factor for the stability of emulsions. We found that interfacial tension of the adding the surfactant to the oil phase is lower than that of the adding the surfactant to aqueous phase. In spite of hydrophilic surfactant, adding the surfactant to aqueous phase produced inferior emulsion to that to oil phase.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2001년도 하계학술대회 논문집
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• pp.369-372
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• 2001

We studied the electro-optical (EO) performance in the vertical-alignment (VA) - l/4$\pi$ cell photoaligned with polarized UV exposure on a homeotropic photopolymer surfaces. Excellent voltage-transmittance curve in the VA - l/4$\pi$ cell photoaligned with polarized UV exposure for 3 min on the photopolymer containing cholesterol group of 8% can be achieved. The V-T characteristics in the VA-l/4$\pi$ cell photoaligned on the photopolymer surface can be improved by increasing cholesteryl group. For response time measurement, the transmittance characteristics of the VA-l/4$\pi$ cell photoaligned on the photopolymer surface was better than that of the VA-l/4$\pi$ cell rubbingaligned on a polyimide(Pl) surface.

• 한국전기전자재료학회논문지
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• 제14권7호
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• pp.595-599
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• 2001

The mechanisms of pretilt angle generation for a nematic liquid cystal (NLC) using a photodimerization method with obliquely polarized UV exposure on the various new photo-crosslinkable polymer were studied. A good thermal stability of all the photo-crosslinkable polymers was obtained by thermogravimetric analysis (TGA) measurement until 450$\^{C}$. High pretilt angle of the NLC was observed by polarized UV exposure on the three kinds of the photo-crosslinkable polymers containing biphenyl(BP), decyl(de), and cholesteryl(chol) group, respectively. However, the low pretilt angle of the NLC was measured by obliquely polarized UV exposure on the two kinds of the photo-crosslinkable polymers containing fluorine and chalcone group. Consequently, the high NLC angle generated is attributable to the biphenyl and alkyl moieties, and photo-dimerized chalcone group of the photopolymer.

• Natural Product Sciences
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• 제15권2호
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• pp.110-113
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• 2009

Acyl-coenzyme A: cholesterol acyltransferase (ACAT) catalyzes cholesterol esterification and plays important roles in intestinal absorption of cholesterol, hepatic production of lipoproteins and accumulation of cholesteryl ester within macrophages and smooth muscle cells. In our study, eight polyacetylenes (1 - 8), were isolated from the roots of Gymnaster koraiensis, and their chemical structures were identified on the basis of spectroscopic analysis and mass. Compound 2 with the (10S)-15,16-epoxy group in skeleton strongly inhibited ACAT enzyme with $IC_{50}$ value of 35.8 ${\mu}g$/mL, meanwhile the other compounds displayed significant inhibition of ACAT enzyme with the $IC_{50}$ values from 45.5 to 55.1 ${\mu}g$/mL.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2001년도 추계학술대회 논문집 Vol.14 No.1
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• pp.350-353
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• 2001

Aligning capabilities for nematic liquid crystal (NLC) using a in-situ photodimerization method on various photo-crosslinkable polyimide (PI) based polymer and blending photopolymer surfaces were stuided. High pretilt angle of the NLC can be measured by obliquely polarized UV exposure on a photo-crosslinkable polyirnide based polymer surface containing biphenyl (BP), decyl (de), and cholesteryl (chol) group, respectively, However, the low pretilt angle of the NLC was measured by obliquely polarized UV exposure on the blending photopolymer (PI and cinnamate materials) surfaces. Consequently, the pretilt angle of the NLC generated on the photo-crosslinkable polyimide based polymer surfaces using the in-situ photodimerization method was higher than that of the blending photopolymers.

• 대한화장품학회지
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• 제22권2호
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• pp.99-114
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• 1996

The MLV liposomes have been developed in many drugs and cosmetics fields. The phospholipid base is made from ceramides, cholesterol, cholesteryl ester, lecithin, lanolin ester, and B-sitosterol, and surfactants are made by using (PEG)n-sitosterol(n=5) and K-cetyl phosphate. We made visicles stable by passing samples through Microfludizer and croated multilamellar vesicles to make MLV liposomes similar to the structure of men's skin. In order to make MLV liposomes, we created lipid membrane films which a mixure of phospholipid base and polyol group was reacted above Tc(95$^{\circ}C$) by gelation for 3 hours. As the optimum conditions of Microfluidizer, we figured out 700 bar for the passing pressure of samples, 4$0^{\circ}C$ for its temperature, and 3 times of frequency to pass through samples. Our MLV liposomes is stable on conditions of a low temperature(5$^{\circ}C$) and a high temperature(45$^{\circ}C$), which is not to be split in a large range. We produced our own moisturizing cream which has a good affinity to skin by means of this system.

• 대한화학회지
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• 제35권3호
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• pp.249-252
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• 1991

남미산 시료 우황(Bezoar Bovis)으로부터 glycodeoxycholic acid, cholesterol, cholesteryl fatty acid ester, palmitic, stearic methyl ester 외에 새로운 성분으로 8-octadecenoic methyl ester 및 cholesta-3,5-diene을 분리하였다.

• 한국식품영양과학회지
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• 제28권4호
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• pp.816-821
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• 1999

Cholesterol esterase(pCEH, pancreas cholesterol ester hydrolase, E.C.3.1.1.13) which is secreted from pancreas has been known as an important lipase for cholesterol uptake. cholesteryl acyl esters from a diet must be hydrolyzed to free cholesterol and fatty acid by cholesterol esterase before the absorption in small intestine. For the development of inhibitory substances from natural source, we screened many extracts of oriental herbs for the inhibition of cholesterol esterase in vitro. The ethanol extract of Ephedra herba showed strong inhibitory activity. Solvent fractionation and silica gel column chromatography with the extract lead to the purification of the inhibitory principle in Ephedra herba. Crystallized inhibitor was identified as ( ) ephedrine by using UV, FT IR, 1H NMR, 13C NMR and GC/Mass. These results suggest that ( ) ephedrine can be used as a potential lead compound for the development of inhibitor for cholesterol uptake by cholesterol esterase inhibition.

• KSBB Journal
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• 제5권1호
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• pp.19-23
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• 1990

콜레스테롤 에스테라아제를 생산하는 미생물 strain CES506 균주를 토양으로부터 분리하여 Aeromonas속의 한 세균으로 동정하였다. 이 균주는 배양액 1ml당 0.023 단위의 콜레스테롤 에스테라아제를 생산하였다. 이 균주가 생산하는 본 효소를 균주 배양액으로부터 약 370배, 24%의 수율로 균질한 상태의 단백질로 정제하였다. 본 효소의 분자량은 SDS-PAGE로 산출한 결과 64,000으로 계산되었다. 본 효소는 cholesteryl-palmitate에 대해 높은 기질 특이성을 나타내었으며 cholesterylpalmitate의 가수분해에 대한 Km값은 0.15mM이었다.

• 한국전기전자재료학회논문지
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• 제14권11호
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• pp.917-921
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• 2001

Aligning capabilities for nematic liquid crystal (NLC) using a in-situ photodimerization method on various Photo-crosslinkable Polyimide (Pl) based polymer and blending photopolymer surfaces were investigated. High pretilt angle of the NLC can be measured by obliquely polarized UV exposure on a photo-crosslinkable polyimide based polymer surface containing biphenyl (BP), decyl (de), and cholesteryl (chol) group, respectively. However, the low pretilt angle of the NLC was measured by obliquely polarized UV exposure on the blending photopolymer (Pl and cinnamate materials) surfaces. Consequently, the pretilt angle of the NLC generated on the photo-crosslinkable polyimide based polymer surfaces using the in-situ photodimerization method was higher than that of the blending photopolymers.