• KIEE International Transactions on Electrophysics and Applications
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• v.12C no.4
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• pp.214-219
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• 2002

The influence of ultraviolet (UV) irradiation and corona on the surface degradation of high temperature vulcanized (HTV) silicone rubber used for outdoor insulation through measuring surface voltage decay after corona charging, surface resistivity, contact angle and X-ray photoelectron spectroscopy (XPS) analysis was studied. The surface resistivity calculated by the surface voltage decay was compared with a value directly obtained from the three electrode method having the guard ring electrode. A good agreement between the two methods for surface resistivity was obtained. UV treated specimens showed the slower decrease of surface voltage decay, while the corona exposed specimens showed a dramatically faster decrease. Although both artificial treatments cause the same oxidative products, which was confirmed with XPS, we could distinguish the difference between the reactions of the two treatments by monitoring the surface voltage decay on corona-charged specimen. In addition, we could derive the specific surface states of the silicone rubber treated by accelerated artificial aging factors and the degradation process.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.15 no.8
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• pp.678-686
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• 2002

This paper presents the effects of accumulation of surface charges on hydrophobic level and the changes of surface potential decay with various artificial environment treatments on high temperature vulcanized (HTV) silicone rubber used for outdoor insulating material. For this study, the charging apparatus by corona discharge, in which grid electrode was installed between the main corona and ground electrode, was used. From this study, it was found that the accumulation of surface charges above a critical surface potential on silicone insulating materials could lead to the temporary loss of surface hydrophobicity. In addition, corona stress and water absorption stress increase the decay rate of surface charges of HTV silicone rubber, while ultraviolet (UV) stress causes longer decay time. We could conclude that the effects of surface charges on hydrophobicity level and the changes of surface state by various artificial treatments were found through a trend of surface potential decay.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.57 no.4
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• pp.417-423
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• 2008

For the evaluation in the safety of outdoor insulator, there are various methods such as: visual observation; voltage measurement; use of ultrasonic wave due to partial discharge; electric field measurement; use of infrared/ultraviolet sensor-type camera. However, many problems have been issued regrading the reliability of the evaluation test and safety of testing operation. Accordingly, the present study has investigated and analyzed the characteristics and mechanisms of the insulator deterioration, in order to obtain an optimal method for detecting poor insulator so that the reliability of power facilities can be enhanced. Besides, based on theoretical analysis of domestic and international detection methods for poor insulator, the reliability has been compared and evaluated quantitatively. As a result, it was shown that the corona camera would be the best choice for domestic workplace application in detecting poor insulator for enhancing the reliability of power transmission line.

• Journal of the Korean Society of Food Science and Nutrition
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• v.41 no.11
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• pp.1540-1545
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• 2012

To investigate the inhibitory effects of Lespedeza cuneataextract (LC) on photo aging, skin aging was induced by UVB irradiation of hairless mice for 5 weeks. The skin erythema indices for the positive control (PC) and Lespedeza cuneata extract (LC-1%, 3%, and 5%) groups were lower than that of the control group. However, both lipid and water capacities of the PC and LC-3% groups were significantly higher than those of the control group. Skin wrinkles in the PC and LC-3% groups formed in a pattern of shallow furrows and thin crests. Skin TBARS contents and XO activity in the LC group were lower than those of the control group. The activities of GSH, SOD, and CAT in the LC-3% group were significant higher than those of the control group. Therefore, Lespedeza cuneata extract could be an effective natural herbal material for the inhibition of skin aging in hairless mice skin.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.39 no.3
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• pp.177-186
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• 2013

Skin dermal fibroblast is the major collagen-producing cell type in human skin. As aging process continues in human skin, collagen production is reduced and fragmentation is increased, which is initiated by matrix metalloproteinase-1 (MMP-1). This imbalance of collagen homeostasis impairs the structure and function of dermal collagenous extracellular matrix (ECM), thereby promoting skin aging. Cysteine-rich protein 61 (CCN1), a member of the CCN family, negatively regulates collagen homeostasis in primary human skin dermal fibroblast cells. It is known in aging fibroblast cells that elevated CCN1 expression substantially reduces type I procollagen and concurrently increases MMP-1, which initiates fibrillar collagen degradation. And proliferation rate of aging fibroblast cells is reduced compared to the pre-aging fibroblast cells. In this study, we confirmed that the replicative senescence dermal fibroblast cells increased the expression levels of MMP-1 and decreased the production of type I procollagen. Our results also showed that the replicative senescence dermal fibroblast cells increased in the expression of CCN1 and decreased in the proliferation rate. Hydrolyzed Ulva pertusa extracts are the materials to improve photo-aging by reducing the expression of MMP-1 that was increased by ultraviolet and by promoting the synthesis of new collagen from fibroblast cells. In this study, we also investigated the hydrolyzed U. pertusa extract to see whether it inhibits CCN1 protein expression in the senescence fibroblasts. Results showed that the hydrolyzed U. pertusa extract inhibited the expression of MMP-1 and increased the production of type I procollagen in the aging skin fibroblast cells cultured. In addition, the proteins that regulate collagen homeostasis CCN1 expression were greatly reduced. The hydrolyzed U. pertusa extract increased the proliferation rate of the aging fibroblast cells. These results suggest that replicative senescent fibroblast cells may be used in the study of cosmetic ingredients as a model of the natural aging. In conclusion, the hydrolyzed U. pertusa extract can be used in anti-wrinkle functional cosmetic material to improve the natural aging skin care as well as photo-aging.

• The Korea Journal of Herbology
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• v.31 no.4
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• pp.87-91
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• 2016

Objectives : In order to confirm whether extracts of different parts of Zostera marina (ZM), a marine flowering plant, can be used as cosmetic ingredients, this study evaluated their cytotoxicity and cytoprotective effects against ultraviolet B (UVB). Inflammatory responses induced by UV stimuli are also associated with the aging of the skin.Methods : We investigated the effects of ZM extracts on cells through the water soluble tetrazolium salt-1(WST-1) assay for cell viability. In order to investigate the anti-inflammatory effects, we evaluated the suppression of Cyclooxygenase-2 (COX-2) expression by ZM extracts in HaCaT cells with UVB-induced damages, and also evaluated the production of Prostaglandin E₂ (PGE₂) in RAW 264.7 cells with LPS-induced damages.Results : High cell viabilities above 90% were observed in all types of ZM extracts, except for whole ZM extract at 0.5 mg/ml; in keratinocytes with UVB-induced damages, the cell viabilities were above 80% when treated with all types of ZM extracts. We confirmed their anti-inflammatory effects by investigating the suppression of inflammatory mediators. In keratinocytes with UVB-induced damages, COX-2 expression decreased in the experimental group treated with ZM extract. Similarly, in RAW 264.7 cells where inflammation was induced with LPS, the biosynthesis of PGE₂ was inhibited.Conclusion : These results suggest that ethanol extracts from Zostera marina may have value as the potential anti-inflammatory medicinal plant. Also based on the abovementioned results, ZM extract protects skin cells from UV-induced damages, and thus can be used in topically applied products for skin protection.

• Journal of Microbiology and Biotechnology
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• v.28 no.8
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• pp.1391-1400
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• 2018

Angelica tenuissima root has historically been used as a traditional medicine in Korea. Previous studies have identified the anti-melanogenic effects of the extract of A. tenuissima root fermented by Aspergillus oryzae (FAT). This study investigated the protective effects of FAT against ultraviolet light B exposure (UVB; $30mJ/cm^2$) in HaCaT (human keratinocyte) or Hs68 (human foreskin fibroblast) skin cells. FAT treatment was able to stimulate wound healing rate at the basal condition. FAT also favored the maintenance and/or improvement of extracellular matrix impairment caused by UVB irradiation through: 1) upregulation of procollagen Type-1 synthesis and secretion; 2) suppression of MMP-1 and elastase expression. FAT was able to play a role in the attenuation of inflammatory responses caused by UVB irradiation via upregulation of photo-protective hemeoxygease-1 and suppression of proinflammatory cyclooxygenase-2 expression. After further verification of the anti-photoaging potential of FAT, it could be utilized as an effective ingredient in anti-aging and anti-wrinkle cosmetics.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.43 no.4
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• pp.321-327
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• 2017

This study was carried out to develop a stable plant-derived natural sunscreen (BHC-S) that replaces the artificially synthesized organic sunscreen agents. The natural sunscreen (BHC-S), which is composed of peanut extract, Centella asiatica extract, and Ecklonia stolonifera extract, has the same level of ultraviolet shielding effect as PARSOL MCX-XR (OMC), which is a synthetic sunscreen. and has safety against skin. MultiFunctional effect such as and anti-wrinkle improvement. Thus, it can be used as raw material for natural cosmetics for ultraviolet ray blocking, and anti-aging.

• Toxicological Research
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• v.28 no.4
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• pp.241-248
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• 2012

Exposure of cells to ultraviolet B (UVB) radiation can induce production of free radicals and reactive oxygen species (ROS), which damage cellular components. In addition, these agents can stimulate the expression of matrix metalloproteinase (MMP) and decrease collagen synthesis in human skin cells. In this study, we examined the anti-photoaging effects of extracts of Tetraselmis suecica (W-TS). W-TS showed the strongest scavenging activity against 2,2-difenyl-1-picrylhydrazyl (DPPH) and peroxyl radicals, followed by superoxide anions from the xanthine/xanthine oxidase system. We observed that the levels of both intracellular ROS and lipid peroxidation significantly increased in UVB-irradiated human skin fibroblast cells. Furthermore, the activities of enzymatic antioxidants (e.g., superoxide dismutase) and the levels of non-enzymatic antioxidants (e.g., glutathione) significantly decreased in cells. However, W-TS pretreatment, at the maximum tested concentration, significantly decreased intracellular ROS and malondialdehyde (MDA) levels, and increased superoxide dismutase and glutathione levels in the cells. At this same concentration, W-TS did not show cytotoxicity. Type 1 procollagen and MMP-1 released were quantified using RT-PCR techniques. The results showed that W-TS protected type 1 procollagen against UVB-induced depletion in fibroblast cells in a dose-dependent manner via inhibition of UVB-induced MMP-1. Taken together, the results of the study suggest that W-TS effectively inhibits UVB-induced photoaging in skin fibroblasts by its strong anti-oxidant ability.

• Molecules and Cells
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• v.42 no.2
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• pp.151-160
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• 2019

Ultraviolet (UV) radiation of the sunlight, especially UVA and UVB, is the primary environmental cause of skin damage, including topical inflammation, premature skin aging, and skin cancer. Previous reports show that activation of nuclear $factor-{\kappa}B$ ($NF-{\kappa}B$) in human skin fibroblasts and keratinocytes after UV exposure induces the expression and release of proinflammatory cytokines, such as interleukin-1 (IL-1) and tumor necrosis $factor-{\alpha}$ ($TNF-{\alpha}$), and subsequently leads to the production of matrix metalloproteases (MMPs) and growth factor basic fibroblast growth factor (bFGF). Here, we demonstrated that TNFR2-SKEE and TNFR2-SKE, oligopeptides from TNF receptor-associated factor 2 (TRAF2)-binding site of TNF receptor 2 (TNFR2), strongly inhibited the interaction of TNFR1 as well as TNFR2 with TRAF2. In particular, TNFR2-SKE suppressed UVB- or $TNF-{\alpha}$-induced nuclear translocalization of activated $NF-{\kappa}B$ in mouse fibroblasts. It decreased the expression of bFGF, MMPs, and COX2, which were upregulated by $TNF-{\alpha}$, and increased procollagen production, which was reduced by $TNF-{\alpha}$. Furthermore, TNFR2-SKE inhibited the UVB-induced proliferation of keratinocytes and melanocytes in the mouse skin and the infiltration of immune cells into inflamed tissues. These results suggest that TNFR2-SKE may possess the clinical potency to alleviate UV-induced photoaging in human skin.