• 한국식물학회:학술대회논문집
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• 한국식물학회 1999년도 Proceedings of the 17th Symposium on Plant Biology Environmental Stress and Photosynthesis
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• pp.68-82
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• 1999

CHilling tolereance of plants are closely correlated with the degree of fatty acid unsaturation of membrane lipids. We studied the effects of low-temperature photoinhibition on the photochemical efficiency of photosystem II in terms of fatty acid unsaturation of thylakoid membranes lipids isolated from chilling -sensitive plants and chilling -resistant ones. To directly test the chilling tolerance of photosynthetic machinery in relation to membrane lipids, we further compared wild type tobacco plants with that of transgenic tobacco plants, in which the sensitivity to chilling had been enhanced by genetic modification of fatty acid unsaturation of chloroplast membrane lipids. The transgenic tobacco plants were found to contain reduced levels of unsaturated membrane fatty acids after being transformed with cDNA for glycerol-3-phophate acyltransferase from squash. The functional integrity of photosystem II during and recovery of photosynthesis from low-temperature photoinhibition will be discussed in connection with the degree of fatty acid unsaturation of chlorophast membranes lipids.

• Journal of Nutrition and Health
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• 제24권3호
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• pp.179-188
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• 1991

Twenty college women were led experimental diet which composed ot basal diet plus different kinds of dietary rats at 27% Cal. Equal amount of 13.5g of corn oil, perilla oil or fish oil was supplied for 2 weeks as a source of n6 linoleic acid(LA). n3 $\alpha$-linolenic acid (LL). or n3 EPA + DHA. respectively. Plasma total Chol level was reduced by perilla and fish oils, significantly only by fish oil. Plasma Chol level was rather increased by corn oil(P<0.05), but was decreased by double amount of corn oil supplement. Therefore, hypocholesterolemic effect of fatty acids was in the order of n3 EPA+DHA>n3 LL>n6 LA and influenced by the degree of fat unsaturation. Plasma TG level was also significantly decreased by n3 EPA+ DHA and increased by n6 LA. Hypotriglyceridemic effect of fatty acids was also in the order of n3 EPA + DHA> n3 LL>n6 LA and influenced by the unsaturation. However, the reduction of plasma TG was more influenced by the fatty acid structure rather than the fat unsaturation. There were no significant effects on lipoprotein pattern 3nd chemical compositions of lipoprotein by different dietary PUFAs. but fish oil diet significantly increased the relative proportion of HDL-Chol. In conclusion. cholesterol- lowering effect of dietary PUFAS seemed to be a function of total fat unsaturation but hypotriglyceridemic effect seemed to be more linked to the ratty acid structure rather than the degree of unsaturation. The hypolipidemic effect of n3 PUFAs was significant so that fish oil or perilla oil may have important nutritional applications in the prevention and treatment of atherosclerotic disease.

• Bulletin of the Korean Chemical Society
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• 제32권1호
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• pp.59-64
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• 2011

Degree of unsaturation in fatty acid molecules plays an important role in the formation of vesicles. Vesicle formation from C18 fatty acids with different amount of double bonds such as oleic acid, linoleic acid and linolenic acid with the incorporation of 1,2-dipalmitoyl-sn-glycerol-3-phosphoethanolamine-N-[methoxy(polyethylene glycol)-2000] (DPPE-PEG2000) have been examined by TEM. Critical vesicular concentrations (CVC) of the vesicle suspension are determined by turbidity and surface tension methods. The CVC of fatty acids increases when the amount of unsaturation in the alkyl chain increases. On the other hand, stability of vesicle suspension has been examined by using particle size and zeta potential at $30^{\circ}C$. There was a dramatic decrease in particle size measurement from mono-unsaturation to tri-unsaturation which could be due to the effect of fluidity in the membrane bilayer caused by different degree of unsaturation. The values of zeta potential for vesicles that were formed without the incorporation of DPPE-PEG2000 were in the range of -70 mV to -100 mV. It has been observed that the incorporation of DPPEPEG2000 to the vesicle reduces the magnitude of zeta potential. However, this phenomenon does not obviously seen in fatty acid vesicles formed by linoleate-linoleic acid and linolenate-linolenic acid. We therefore conclude that the addition of DPPE-PEG2000 does not effectively improve the stability of the linoleate-linoleic acid and linolenatelinolenic acid vesicle at pH 9.0 after the evaluation of their particle size and zeta potential over a period of 30 days. Although the vesicles formed were not stable for more than 10 days, they have displayed the potential in encapsulating the active ingredients such as vitamin E and calcein. The results show that the loading efficiencies of vitamin E are of encouraging value.

• Journal of Nutrition and Health
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• 제25권7호
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• pp.555-568
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• 1992

This study was to compare the effects of dietary n-6 and n-3 fatty acids and fat unsaturation on plasma lipids and chemical composition of VLDL and LDL fraction and lipogenic enzymes activity in rat liver under the conditions providing 1) a similar amount of n-6, n-3 fatty acids(LA, ALA, EPA+DHA) in diets and 2) the various degree of fat unsaturation. Male Sprague-Dawley rats weighing 420g were treated for 6-n with six experimental diets providing 25% of energy as fat and which were different only in fatty acid composition. The fats used for a source of each fatty acid were beet tallow for saturated fatty acid corn oil for n-6 linoleic acid(LA) perilla oil for n-3 $\alpha$-linolenic acid(ALA) and fish oil n-3 eicosapentaenoic acid (EPA) and n-3 docosahexaenoic acid(DHA). Plasma cholesterol level was increased by corn oil to compare with beef tallow but was decreased by perilla oil or fish oil. Plasma TG level was significantly decreased by perilla oil or fish oil. Fish oil significantly reduced the level of HDL-Chol and the proportion of Chol in LDL fraction and that of TG in vVLDL fraction. Overall there was a singificant negative correlation between the level of each plasma lipid(Chol TG, VLDL-TG, LDL-C) and the degree of fat unsaturation. However this rerlationship is not always true when compared the hypolipidemic effect of each fatty acid at a similar level of fat unsaturation. There was a trend such taht glucose 6-P dehydrogenase 6-phosphogluconate dehydrogenase and malic enzyme activites were reduced by n-3 fatty acids. Perilla oil significantly increased the incorporation of c20:5 and c22:5 into liver tissue and fish oil suignificantly increased the incorporation of c20:5, c22:6 into liver tissue and the effect of long chain n-3 fatty acid incorporation was greater by fish oil. therefore the hypotriglyceridemic effect of n-3 fatty acid could be resulted from the interference of hepatic lipogenesis by long-chain n-3 fatty acids and the reduced proportion of TG in VLDL fraction and its effect was greater by n-3 EPA+DHA than n-3 ALA even though plasma Chol and TG levels were also influenced by the degree of dietary fat unsaturation.

• 한국결정성장학회지
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• 제8권2호
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• pp.365-369
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• 1998

다분자흡착층에서의 흡착이론을 고려한다. 사용된 다분자흡착층 모형이 매우 간단한 것임에도 불구하고, 이로부터 유도된 흡착등온식은 실리카겔 기판상의 $Br_2$ 기체의 흡착과 같은 비포화흡착현상을 정성적으로 잘 설명하고 있다.

• Journal of Photoscience
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• 제5권1호
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• pp.1-10
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• 1998

The susceptibility of chilling-resistant spinach plants. and of chilling-sensitive squash plants to photoinhibition was compared in terms of the activity of photosystem II, in relation to the deuce of fatty acid unsaturation of chloroplast membrane lipids. From thylakoid membranes of the plants. monogalactosyl diacylgtycerol, digalactosyl diacylglycerol. sulfoquinovosyt diacylglycerol, and phosphatidylglycerol were seperated as major lipid classes. It was found that the content of cis-unsaturated fatty acids of phosphatidylglycerol was greater by 32% in spinach than that in squash. When leaf disks were exposed to light at 5$\circ$C, 15$\circ$C and 25$\circ$C, photochemical efficiency of photosystem II. measured as the ratio of the variable to the maximum fluorescence of chlorophyll, declined markedly in squash plants, as compared to spinach plants. When leaf disks were exposed to strong light in the presence of lincomycin, an inhibitor of protein synthesis in chloroplasts, photoinhibition was accelerated in the two types of plants. Moreover, lincomycin treatment abolished the differences in the degree of susceptibility to strong light, which had been observed between the two types of plants. When the extent of photoinhibition of photosystem II-mediated electron transport was compared in thylakoid membranes isolated from the two types of plants, there were no differences in the degree of inactivation of photosystem II activity. However, when intact leaf disks were exposed to strong light either at 10$\circ$C or at 25$\circ$C, and then were allowed to recover either at 17$\circ$C or at 25$\circ$C in dim light. chilling-resistant plants such as spinach and pea showed marked recovery from photoinhibition, in contrast to chilling-sensitive plants, such as squash and sweet potato. whose recovery was strongly dependent on the temperature. These findings are discussed in relation to the unsaturation of fatty acids in membrane phosphatidylglycerol. It appears that fatty acid unsaturation of membrane lipids accelerates the recovery of photosystem H from photoinhibition, without affecting the photo-induced inactivation process of photosystem II associated with photoinhibition.

• Geomechanics and Engineering
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• 제23권3호
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• pp.207-215
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• 2020

This paper presents a kinematic limit analysis for passive earth pressure of rigid retaining structures considering the unsaturation of the backfill. Particular emphasis in the current work is focused on the effects of the spatial change in the degree of saturation on the passive earth pressure under different steady-infiltration/evaporation conditions. The incorporation of change of effective unit weight with degree of saturation is the main contribution of this study. The problem is formulated based on the log-spiral failure model rather than the linear wedge failure model, in which both the spatial variations of suction and soil effective unit weight are taken into account. Parametric studies, which cover a wide range of flow conditions, soil types and properties, wall batter, back slope angle as well as the interface friction angle, are performed to investigate the effects of these factors on the passive pressure and the corresponding shape of potential failure surfaces in the backfill. The results reveal that the flow conditions have significant effects on the suction and unit weight of the clayey backfill, and hence greatly impact the passive earth pressure of retaining structures. It is expected that present study could provide an insight into evaluation of the passive earth pressure of retaining structures with unsaturated backfills.

• 한국토양비료학회지
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• 제24권2호
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• pp.144-151
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• 1991

수도품종(水稻品種)의 내냉성관련인자(耐冷性關聯因子)로서 생체막구성물질(生體膜構成物質)에 중요(重要)한 역할(役割)을 하는 인지질(燐脂質)의 지방산조성(脂肪酸組成)과 지방산(脂肪酸)의 불포화비율(不飽和比率)을 증가(增加)시킬 수 있는 경화처리(硬化處理)에 의한 지방산(脂肪酸)의 변화(變化)를 조사(調査)하여 포장(圃場)에서 조사(調査)된 내냉성정도(耐冷性程度)와 비교검토(比較檢討)한 결과(結果)는 다음과 같다. 1. 수도(水稻) 32품종(品種)에서 분리(分離)한 인지질(燐脂質)의 지방조성(脂肪組成)은 Pamitic, Linoleic 및 Linolenic acid가 주(主) 지방산(脂肪酸)이었고, Palmitoleic, Stearic 및 Oleic acid가 소량(少量) 함유(含有)되어 있었다. 2. 저온처리(低溫處理)($15^{\circ}C$, 3일간)한 묘(苗)에서 포화지방산(飽和脂肪酸)인 Pamitic acid의 함량(含量)은 감소하고, 불포화지방산(不飽和脂肪酸)인 Linoleic acid의 함량(含量)은 증가하였다. 3. 지방산(脂肪酸)의 불포화비율(不飽和比率)은 저온처리(低溫處理)를 하므로써 높아졌으며, 내냉성(耐冷性)이 강(强)한 품종(品種)에서 비율(比率)이 높고, 약(弱)한 품종(品種)에서 낮아 내냉성정도(耐冷性程度)와 일치(一致)하는 경향을 보였다. 4. 경화처리(硬化處理)에 의하여 인지질지방산조성(燐脂質脂肪酸組成)중 Pamitic acid는 감소하고, Linoleic acid의 함량(含量)은 증가하였다. 5. 경화처리(硬化處理)를 하므로써 지방산(脂肪酸)의 불포화비율(不飽和比率)은 대조구(對照區)에 비하여 18~24% 증가되었다.

• 한국동물학회:학술대회논문집
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• 한국동물학회 1994년도 한국생물과학협회 학술발표대회
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• pp.200.1-200
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• 1994

No Abstract, See Full Text

• Journal of Microbiology
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• 제33권4호
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• pp.322-327
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• 1995

Tolerance of Mycobacterium sp. against organic solvents has been induced for the cholesterol side chain degradation by adding chemicals associated with synthesis of fatty acids or alcohols. Biotin of 300 .mu.g/1 and 0.5% aqueous ethanol solution were optima for the enhancement of ethanol tolerance of the microorganism. The induction of ethanol tolerance by biotin was found to be due to increase of degree of unsaturation of the fatty acids in membranous phospholipid of the cell, especially due to increase of oleic acid content. However when 0.5% of ethanol was added for the ethanol tolerance induction, there was an ambiguous correlation between ethanol tolerance and degree of unsaturation of the fatty acids, in spite of the fact that the induction increased the content of unsaturated fatty acids. Addition of 0.5% of ethanol induced several ethanol shock proteins having molecular weight similar to that of heat shock proteins.