• 한국염색가공학회지
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• 제26권4호
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• pp.297-304
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• 2014

In this study, we investigated the relationship between the adsorption property of Methyl violet or Tartrazine dye onto silica sol surface and surface charge density of the sol. The adsorption ratio of Methyl violet dye on silica sol decreased to 74% and 92% for the 68nm and 94nm silica sol, respectively, at dye concentration of $175{\mu}g/m^2$. However, the adsorption ratio of Tartrazine dye on 68nm and 94nm silica sol was about 0% for both of them. The surface charge density is $-0.40C/m^2$, $-0.26C/m^2$ for 68nm and 94nm silica sol, respectively. The amount of Methyl violet dye adsorbed on silica sol increased with an increase of surface charge density of particle at the same concentration of the dye. The adsorbed amount of the silica having high surface charge density is larger at high pH domain. But adsorbed amount of the silica having low surface charge density is larger at low pH domain.

• Tribology and Lubricants
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• 제25권4호
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• pp.261-264
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• 2009

Environmental factors affect parts of the automobile. When dust particles are embedded, specially, friction and wear of the rubber-seal in automobile chassis system are increased. Increase in friction and wear leads to weakness of component and reduction of mechanical life. In this study, the wear characteristics of rubber-seal for inflow of dust particles are investigated. Silica($SiO_2$) and alumina($Al_2O_3$) particles are used as a dust particle because these particles are main elements of dust particles. The sliding wear tester are used for investigate the wear characteristics of rubber-seal. If the single dust particle($SiO_2$) is embedded in the rubber-seal component, the influence of dust particle size is more than that of inflow rate on the wear characteristics of rubber-seal. If the mixed dust particles are embedded in the rubber-seal component, the wear rate is increased as the rate of alumina that has a bigger hardness is increased. If the mixed dust particles that have different hardness are embedded in the rubber-seal component, the influence of particle size is more than that of particle hardness.

• 동의생리병리학회지
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• 제25권3호
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• pp.425-430
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• 2011

This study evaluated the effect of extraction conditions of yam (Dioscorea aimadoimo) on antioxidant, moisturizing, collagenase activity, proliferation, and migration. Yam has been recognized as a healthy food due to its various biological activities, such as anti-obesity, anti-constipation, anti-mutagenic activities, as well as its ability to decrease blood glucose and cholesterol levels. Electron donating ability of high temperature ethanol extract of Dioscorea aimadoimo (HDA) had shown 70.6% at 400 mg/ml, and low temperature ethanol extract of Dioscorea aimadoimo (LDA) had shown 40% at 400 mg/ml. SOD-like activities of LDA and HDA were 23% and 34% at 400 mg/ml respectively. LDA significantly reduced the activity of collagenase in a dose-dependent manner, which was higher than HDA. The water contents in LDA-treated skin and HDA-treated skin were increased by 45.63% and 38.65% than the placebo cream respectively. The cellular proliferation of human dermal fibroblast neonatal (HDFn) was evaluated by MTT and cell migration assay. Compared to control, the cell proliferation was elevated to 109.7% and 114% by the treatment of LDA and HDA respectively at the concentration of 200 mg/ml. In addition, LDA and HDA were induced cell migration in HDFn. Our study suggests that LDA and HDA should be a very useful cosmetic ingredient, as anti-aging and skin moisturizer.

• 동의생리병리학회지
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• 제24권4호
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• pp.674-680
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• 2010

The purpose of this study was to investigate the effects of Fructus Ligustri Lucidi (FLL) on the process of melanogenesis. Cell viability of B16F10 cells was measured by MTT assay and melanin content was assessed using the method of Hosoi with some modifications. Methanol extract of Fructus Ligustri Lucidi (MFLL) significantly inhibited melanin synthesis in a concentration-dependent manner, and it reduced the activity of tyrosinase, the rate-limiting melanogenic enzyme. Additionally, $\alpha$-melanocyte stimulation hormone ($\alpha$-MSH)-induced hyperpigmentation was down-regulated by MFLL. MFLL was fractionated by organic solvent. In the present study, Hexane extract of Fructus Ligustri Lucidi (HFLL) inhibited tyrosinase activity and melanin production of B16F10 cells in the absence or presence of $\alpha$-MSH. Ethyl acetate, butanol and water layers did not affect tyrosinase activity and melanin production. Meanwhile ethyl acetate, butanol and water layers showed DPPH free radical scavenging activity. These results suggest that extract of FLL could be used as functional biomaterial in developing a skin whitening agent having the antioxidant activity.

• 동의생리병리학회지
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• 제23권3호
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• pp.574-580
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• 2009

Melanogenesis is induced mainly by ultraviolet radiation of sunlight and ${\alpha}$-Melanocyte stimulation hormone (${\alpha}$-MSH) which binds to a specific G protein coupled receptor. ${\alpha}$-MSH and cAMP-elevating agents are known to melanin syntheisis and dendrite outgrowth. The purpose of this study was to investigate the mechanism of melanogenesis inhibition in B16/F10 cells by ethanol extract of Artemisiae Capillaris Herba. In the present study, ${\alpha}$-MSH led to a stimulation of melanin synthesis that appeared to result from an increased tyrosinase activity and melanin content. However, the ethanol extract of Artemisiae Capillaris Herba inhibited the ${\alpha}$-MSH-induced tyrosinase activity and melanin content. In control conditions, B16/F10 cells displayed a fibroblastic appearance while ${\alpha}$-MSH treatment promoted the emergence of small and numerous dendrites from the plasma membrane. The ethanol extract of Artemisiae Capillaris Herba abolished the ${\alpha}$-MSH-induced dendricity. Regarding protein levels of the melanogenic enzymes, the amounts of tyrosinase were increased after incubation with ${\alpha}$-MSH. The treatment of Artemisiae Capillaris Herba ethanol extract decreased the ${\alpha}$-MSH expression levels of tyrosinase. Based on these findings, it is likely that the ethanol extract of Artemisiae Capillaris Herba exerts its depigmenting effects in B16/F10 cells through the suppression of tyrosinase expression, which are key enzymes for melanogenesis.

• 동의생리병리학회지
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• 제23권3호
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• pp.695-699
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• 2009

UV irradiation causes skin-aging involving coarse wrinkles, thickening, dyspigmentation, and rough skin surface. This study was carried out to develop health & functional food by using Korean red ginsneg and Fagopyrum esculentum extract mixture (RGFE) for prevention of skin wrinkles. The RGFE-treated group showed the more effective collagenase inhibition rate than the red ginseng (RG)-treated group. To investigate photo protective effects of RGFE on UV-induced damaged skin, SKH hairless male mice were orally administerd RGFE and regional treatment and irradiated with UV for up to 8 weeks. In RGFE-treated group, better skin, and less wrinkle formation were observed compared with UV group. Epidermal thickness of hairless mouse was significantly decreased in RGFE, RG, and Fagopyrum esculentum (FE) groups compared with UV group. These results demonstrate RGFE have photo-protective effects on UV-damaged hairless mouse skin.

• Journal of Preventive Medicine and Public Health
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• 제30권4호
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• pp.852-869
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• 1997

This study was conducted to develop and evaluate the reliability and the validity of a questionnaire in order to determine the applicability as a screening tool for estimating environmental exposure and health effects related to air pollution. The questionnaire was developed with adopting some items of others such as ISAAC or ATS-DLD. And then we performed test-retest to 89 middle school students and their mothers at interval of three months. Cohen's Kappa values, weighted Kappa values, Spearman's correlation coefficients, and Pearson's correlation coefficients for each item were computed as reliability coefficients. The validity coefficients and validity coefficient bounds were also obtained by simply using these reliability coefficients. As results, Kappa ranged broadly from 0.10 to 0.61 of the items 'diet', $0.52\sim0.79$ of the environmental tobacco smoke, $0.39\sim0.44$ of the functional categories of surrounding environment, and $0.39\sim0.44$ of the using transportation systems; these items were regarded as confounding factors. For items related to health outcomes, Kappa ranged from -0.02 to 0.37 in the respiratory system of past medical history, and from 0.11 to 0.55 in the current health status. But Kappa of the others were over 0.60. In conclusion, if some items can be corrected or modified, the questionnaire developed in this study can be used as a tool for evaluating environmental exposure and health effects associated with air pollution.

• 생약학회지
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• 제46권1호
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• pp.12-16
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• 2015

Myrrh is a resinous substance obtained from Commiphora trees, which has long been used as an antiseptic agent. A sesquiterpene, $1{\beta}$, $6{\alpha}$-dihydroxyeudesm-4(15)-ene (DE), was isolated from the hot water extract of Myrrh. In the present study, we found that DE attenuates the lipopolysaccharide (LPS)-induced inflammation in BV2 microglial cells. DE significantly inhibited LPS-induced production of pro-inflammatory mediators such as nitric oxide (NO) and prostaglandin $E_2$ ($PGE_2$) in BV2 microglia in a concentration-dependent manner without cytotoxic effect. Furthermore, DE dose-dependently suppressed the protein expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2). These results suggest that DE may be a good candidate to regulate LPS-induced inflammatory response.

• 생약학회지
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• 제49권1호
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• pp.40-46
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• 2018

Chaenomeles sinensis (Thouin) Koehne fruit (Rosaceae) has been used as a traditional medicine in Korea, Japan and China to treat sore throat, diarrhea and inflammation. The ethanol extract of C. sinensis fruit was successively partitioned as methylene chloride, ethyl acetate, n-butanol and $H_2O$ soluble fractions. Among those fractions, the n-butanol fraction showed the most potent DPPH radical scavenging and superoxide quenching activities. To verify antioxidant activities, the n-butanol fraction was checked the activities of superoxide dismutase (SOD) and catalase activities, and intracellular ROS levels and oxidative stress tolerance in Caenorhabditis elegans. Furthermore, to see if increased stress tolerance of worms by treating of the n-butanol fraction was due to regulation of stress-response gene, we quantified SOD-3 expression using transgenic strain. Consequently, the n-butanol fraction elevated SOD and catalase activities of C. elegans, and reduced intracellular ROS accumulation in a dose-dependent manner. Moreover, the n-butanol fraction-treated CF1553 worms exhibited significantly higher SOD-3::GFP intensity.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2009년도 추계학술대회 논문집
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• pp.399-399
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• 2009

CIS계 화합물 태양전지는 높은 광흡수계수와 열적 안정성 및 Ga 조성 조절을 통한 밴드갭 조절이 용이해 고효율 박막 태양전지로 각광 받고 있다. CIS 태양전지의 광 흡수층 제조 방법으로는 여러 가지 방법이 있지만 본 연구에서는 가장 높은 에너지 변환 효율을 달성한 Co-Evaporation 방법을 사용하기로 하였다. 미국의 NREL의 경우 Co-Evaporation 방법을 사용해 20%의 에너지 변환 효율을 달성한 바가 있다. 하지만 이러한 효율의 태양전지는 실험실에서 연구용으로 제작한 아주 작은 면적으로 태양전지 양산화에 그대로 적용하기는 힘들다. 따라서 CIGS 태양전지의 양산화 적용을 위해 대면적화가 필수적이다. 본 연구에서는 기존의 3 stage 방식을 이용해 광흡수층을 증착하여 최적화 조건을 연구하였다. 또한 기판의 면적 증가에 따라 효율과 Voc, Jsc, F.F가 얼마나 감소하는지 실험하여 보았다. 기판은 soda lime glass를 사용 하였으며 후면 전극으로 약$1{\mu}m$ 두께의 Mo를 DC Supptering 방법을 이용해 증착하였다. 다음으로 약 $2{\mu}m$이상의 광흡수층을 Co-Evaporation 방법을 이용하여 증착 하였으며 buffer층으로는 약 50nm의 CdS층을 CBD방법을 이용하여 제조 하였다. TCO층으로 약 50nm의 i-ZnO와 약 450nm의 Al-ZnO를 RF Sputtering 방법을 이용하여 증착 하였다. 마지막으로 앞면 전극으로 약 $3{\mu}m$의 Al을 Thermal Evaporation 방법으로 증착하였다. 태양전지 소자의 면적은 $0.49cm^2$, $25cm^2$, $100cm^2$로 각각 면적을 달리하며 효율을 비교 분석하였다.