• 공업화학
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• 제26권3호
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• pp.351-355
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• 2015

호기성 벤질 알코올 산화반응을 위하여 팔라듐이 담지된 이산화티타늄 촉매를 제조하였다. 반응점으로 사용되는 팔라듐 입자의 특성을 조절하기 위하여 8종류의 상온 이온성액체를 촉매 합성 시 사용하였다. 최적의 촉매특성을 규명하기 위하여 300, $400^{\circ}C$ 및 $500^{\circ}C$로 소성하여 반응을 수행하였다. 소성온도가 증가할수록 비표면적과 기공부피가 감소 하였지만, 기공크기는 커다란 변화가 없었다. 그러나 사용한 이온성액체의 종류에 따라 촉매의 물리적 특성은 다르게 나타났다. 동일한 반응조건에서 사용한 이온성액체와 소성온도에 따라 촉매의 반응활성에 차이를 보였다. 대부분의 경우 $400^{\circ}C$에서 소성한 촉매가 우수한 반응활성을 보였다. 하지만 1-Octyl-3-methylimidazolium hexafluorophosphate 와 1-Octyl-3-methylimidazolium trifluoromethanesulfonate를 이용하여 제조한 촉매의 경우 $300^{\circ}C$에서 소성한 경우 반응활성이 우수하였다. 본 실험에서 사용한 촉매들 중에서 1-Octyl-3-methylimidazolium tetrafluoroborate를 사용하고 $400^{\circ}C$에서 소성한 촉매가 가장 우수한 반응활성을 보였다.

• Journal of Applied Biological Chemistry
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• 제55권1호
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• pp.35-39
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• 2012

선학초 열수 추출물과 에탄올 추출물의 분획물을 항산화 및 주름개선의 소재로 이용하기 위하여 생리활성을 검증하였다. 항산화효과를 확인하기 위하여 전자공여능을 측정한 결과 선학초 열수추출물(AW)과 에탄올추출물(AE) 모두 ethyl acetate층 1,000 ppm에서 각각 96.2, 92.3%의 효과를 나타내었고, SOD 유사활성능을 측정한 결과 AW의 ethyl acetate층에서 61.8%의 활성을 AE의 $n$-butyl alcohol 층에서 58.0%의 높은 활성을 각각 나타내었다. 또한 xanthine oxidase저해활성을 측정한 결과 AW와 AE에서 모두 ethyl acetate층 1,000 ppm일 때, 각각 84.9, 92.5%의 가장 높은 저해율을 나타내었다. 주름개선 효능 확인을 위해 elastase 저해활성을 측정한 결과 이 또한 AW와 AE 모두에서 ethyl acetate층이 각각 55.2, 70.1%의 효능을 나타내었으며, collagenase 저해활성을 측정한 결과 AW의 ethyl acetate층이 90.6%로 가장 높은 저해율을, AE는 88.6%로 $n$-butyl alcohol 층이 가장 높은 저해율을 나타내었다. 이상의 결과로 미루어 보아 선학초의 열수 추출물과 에탄올 추출물의 분획물이 in vitro상에서 항산화 및 주름개선의 활성이 있음을 확인할 수 있었다.

• Journal of Microbiology and Biotechnology
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• 제13권5호
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• pp.738-744
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• 2003

The gene ADH encoding NAD-dependent alcohol dehydrogenase from Bacillus stearothennophilus was cloned and overexpressed as a GST fusion protein at a high level in Escherichia coli. The expressed fusion protein was purified simply by glutathione affinity chromatography. GST fusion protein was then cleaved by thrombin, while soluble enzyme was further purified by glutathione affinity chromatography. The recombinant enzyme had the same elctrophoretic mobility as the native enzyme from Bacillus stearothennophilus. The recombinant enzyme catalyzed the oxidation of a number of alcohols and exhibited high activities towards secondary alcohols. The $K_m\;and\;V_{max}$ values of the recombinant enzyme for ethanol were 5.11 mM and 61.35 U/mg, respectively. Pyridine and imidazole notably inhibited the enzymatic activity. The activity of the recombinant enzyme optimally proceeded at pH 9.0 and $70^{\circ}C$. The midpoint of the temperature-stability curve for the recombinant enzyme was approximately $68^{\circ}C$, and the enzyme was not completely inactivated even at $85^{\circ}C$. The recombinant enzyme showed a high resistance towards denaturing agents (0.05% SDS, 0.1 M urea). Therefore, due to its stability and relatively broad substrate specificity, the recombinant enzyme could be utilized in bio-industrial processes and biosensors.

• 대한본초학회지
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• 제27권6호
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• pp.91-98
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• 2012

Objectives : Rhodiola rosea L. (Crassulaceae) is a plant living at the areas of high-altitude mountain, and Rhodiolae Radix(the root of R. rosea) has been used as a traditional medicine to decrease the symptoms of mental- or physical-stress in Asia and Europe. To examine the efficacy of Rhodiolae Radix on the oxidative stress, the anti-oxidative effects of the radix were examined, Methods : The effects of Rhodiolae Radix on several oxidative factors were examined in vitro, and also the effects were tested in the liver of rats which were treated with a high dose of alcohol during 2 weeks. Results : The extract of Rhodiolae Radix in vitro scavenged some oxidants, such as DPPH, Superoxide anion radical and LDL, and the extract also inhibited the oxidative capacity of linoleic acid, significantly. Meanwhile, in the in vivo test, the methanol-extract decreased some oxidation parameters, such as relative liver weight, TBARS and SOD activities, and also increased catalase activity in the liver of alcohol-loaded rats, But, the extract had no effects on GSH content and GSH-px activiy in the rats. Conclusion : The root of Rhodiola rosea has a strong anti-oxidative capacity, and also has some preventive properties aginst the alcoholic stress.

• East Asian mathematical journal
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• 제36권3호
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• pp.365-376
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• 2020

Nonalcoholic fatty liver is a type of fatty liver in which fat accumulates in the liver without alcohol. In the accumulation, Nrf1 and miR-378 genes play very important role, so called negative feedback loop, in which the two genes suppress the other's production. In other words, Nrf1 activates fatty acid oxidation which promotes fat consumption in the liver, while miR-378 deactivates fatty acid oxidation. Thus, both genes regulate nonalcoholic fatty liver. In this paper, the negative feedback loop of Nrf1 and miR-378 are expressed by a system of ordinary differential equations. And, bifurcation simulation shows the change in the amount of each gene with significant parameter range changes. Bifurcation simulation has also used to determine the thresholds for transit between disease and steady state.

• 대한화장품학회:학술대회논문집
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• 대한화장품학회 2003년도 IFSCC Conference Proceeding Book I
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• pp.499-500
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• 2003

To investigate the potency of some natural extracts as skin whitening agents, in this study, 25 natural plants were prepared from natural sources including medicinal plants, such as Angelica dahurica using methylene dichloride, ethyl acetate, n-butyl alcohol, and water as the extraction and/or the partitioning solvents. These natural extracts were subsequently subjected to in-vitro DOPA auto-oxidation test in the media containing human or mushroom tyrosinase as the oxidation promoting enzymes. Most of the extracts showed relatively higher enzyme inhibition(omitted)

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2001년도 총회 및 춘계학술발표회
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• pp.136-139
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• 2001

In this study, we have examined potential degradation of MTBE (methy1 tert-butyl ether) by pure culture ENV425 and mixed culture isolated from gasoline contaminated soil using n-butane as the sources of carbon and energy. The results described in this study suggest that MTBE is degraded cometabolically by ENV425 and mixed culture grown n-butane, and the disappearance of TBA after complete degradation of MTBE suggest the further degradation of TBA. Butane and MTBE degradation was completely inhibited by acetylene, which indicated that both substrates were degraded by butane-utilizing bacteria. MTBE was degraded ENV425 and mixed culture grown n-butane, and TBA (tert-butyl alcohol) was produced as product of MTBE oxidation. TBA production was accounted 54.7% and 58.6% for MTBE oxidation by ENV425 and mixed culture, respectively. The observed maximal transformation yield (T$_{y}$) were 44.7 and 34.0 (nmol MTRE degraded/$\mu$mol n-butane Utilized) by ENV425 and mixed culture, respectively.y.

• 한국식품과학회지
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• 제44권5호
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• pp.592-599
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• 2012

된장의 소금농도를 10%에서 6%로 줄이고 알코올 또는 겨자, 마늘을 단독 또는 혼합 첨가한 저식염 된장의 숙성 중 품질특성을 비교하였다. 된장의 amylase 활성은 숙성 2-4주에 높았으며 겨자 첨가 된장이 숙성 후기에 낮은 활성을 보였다. 메주 된장이 koji 된장에 비하여 효소 활성이 낮았으며, protease는 중성보다 산성 protease 활성이 높았다. 된장의 효모수는 겨자나 알코올, 마늘의 첨가로 현저하게 줄었으나 세균수는 겨자 첨가구에서 숙성 후기에 조금 적었다. 산화환원전위는 겨자 또는 겨자-마늘 첨가 된장에서 숙성 후기에 낮았으며, 수분활성도의 저하는 알코올 첨가구에서 심하였다. 알코올 첨가 된장이 숙성 중에 L-과 b-값이 저하가 심하였고 메주 된장은 L-값이 낮았고 a-값이 높았다. 된장의 pH는 겨자 또는 마늘 첨가구에서 낮았고 적정산도의 증가가 심하였으나, 알코올의 첨가로 적정산도와 산가는 적었다. 된장의 환원당은 알코올-마늘과 겨자-마늘 혼합 첨가구에서 높았으며, 알코올의 생성은 겨자의 첨가로 억제되었다. 된장의 아미노산성 질소는 마늘과 겨자 첨가구에서 높았으며 암모니아성 질소의 생성은 겨자 첨가구에서 낮았다. 8주 숙성시킨 된장의 맛과 종합적인 기호도는 알코올과 알코올-마늘 첨가 된장이 양호하여 저식염 된장의 제조는 소금의 일부를 알코올 또는 마늘로 대체하거나 이를 혼합하여 첨가하는 것이 효과적이었다.

• 대한약리학회지
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• 제20권1호
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• pp.47-54
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• 1984

Effect of ascorbic acid on various hepatic ethanol metabolizing enzymes including alcohol dehydrogenase(ADH), the microsomal . ethanol oxidizing system(MEOS), and catalase was quantitatively evaluated in liver microsomal and cytosolic preparation from Sprague-Dowley rats. In present study, ADH activities were no changed significantly by ascorbic acid. The MEOS activity, dependent on NADPH and $O_2$, was affected by azide (inhibitor of catalase) or exogenous catalase. In the presence of ascorbic acid, ethanol oxidation by rat liver microsomal preparation reacted with NADPH-generating system was increased by up to 22.5%, but decreased when liver microsome was reacted with $H_2O_2$ generated by xanthine and xanthine oxidase. Increase in the activity of the MEOS in the presence of ascorbic acid was greater in liver microsomal preparation pretreated with azide. Also ascorbic acid oxidized ethanol nonenzymatically. This ethanol oxidation induced by ascorbic acid was inhibited by OH radical scavengers (thiourea, sodium benzoate), but was not much affected by superoxide dismutase. From these results it was suggested that ascorbic acidcould interact directly with the MEOS, then promote the oxidation of ethanol. And, to some extent, ${\cdot}OH$-radicals or other radicals generated during the spontaneous autooxidation of ascorbic acid may be responsible for the production of acetaldehyde from ethanol.

• 한국주조공학회지
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• 제28권1호
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• pp.20-24
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• 2008

The characteristics, such as roughness, thickness, microhardness and corrosion resistance, of plasma electrolytic oxide coatings on AZ91D alloy were investigated under the processing condition of various coating times. The coatings on AZ91D alloy consisted of MgO, $MgAl_{2}O_{4}$ and $Mg_{2}SiO_{4}$ oxides. The surface roughness and thickness of coatings became larger with increasing the coating time. The microhardness in cross section of coatings was much higher than not only that in surface but that in the conventional anodic oxide coatings, which increased progressively as the coating time increased. After being immersed in 3.5%NaCl solution and methyl alcohol, the corrosion resistance of AZ91D alloy was markedly improved by plasma electrolytic oxidation coating treatment, and the AZ91D alloy coated for 50min revealed excellent corrosion resistance.