• Proceedings of the Korean Vacuum Society Conference
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• 2010.08a
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• pp.311-312
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• 2010

The fabricated photovoltaic cells based on PIN heterojunctions, in this study, have a structure of ITO/poly(3, 4-ethylenedioxythiophene)-poly(styrenesulfonate)(PEDOT:PSS)/donor/donor:C60(10nm)/C60(35nm)/2, 9-dimethyl-4, 7-diphenyl-1, 10-phenanthroline(8nm)/Al(100nm). The thicknesses of an active layer(donor:C60), an electron transport layer(C60), and hole/exciton blocking layer(BCP) were fixed in the organic photovoltaic cells. We investigated the performance characteristics of the PIN organic photovoltaic cells with copper phthalocyanine(CuPc), tetracene and pentacene as a hole transport layer. Discussion on the photovoltaic cells with CuPc, tetracene and pentacene as a hole transport layer is focussed on the dependency of the power conversion efficiency on the deposition rate and thickness of hole transport layer. The device performance characteristics are elucidated from open-circuit-voltage(Voc), short-circuit-current(Jsc), fill factor(FF), and power conversion efficiency($\eta$). As the deposition rate of donor is reduced, the power conversion efficiency is enhanced by increased short-circuit-current(Jsc). The CuPc-based PIN photovoltaic cell has the limited dependency of power conversion efficiency on the thickness of hole transport layer because of relatively short exciton diffusion length. The photovoltaic cell using tetracene as a hole transport layer, which has relatively long diffusion length, has low efficiency. The maximum power conversion efficiencies of CuPc, tetracene, and pentacene-based photovoltaic cells with optimized deposition rate and thickness of hole transport layer have been achieved to 1.63%, 1.33% and 2.15%, respectively. The photovoltaic cell using pentacene as a hole transport layer showed the highest efficiency because of dramatically enhanced Jsc due to long diffusion length and strong thickness dependence.

• Korean Journal of Medicinal Crop Science
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• v.15 no.4
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• pp.271-275
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• 2007

Naturally occurring substances are important biomedical resources with low toxicity and ethnopharmacology-based efficacy. Four out of 45 extracts (Celastrus orbiculatus, Cercis chinensis, Stephanadra incisa, and Weigela subsessilis) prepared from the bark of Korea Forest plants exhibited more than 50% of inhibition on $TNF-{\alpha}$ production in lipopolysaccharide (LPS)-activated RAW264.7 cells at $100\;{\mu}g/m{\ell}$. In particular, potential inhibitory components of 4 extracts showed more than 50% inhibition seemed to be concentrated in methylene chloride (MC) fraction from C. orbiculatus, in ethyl acetate (EtOAc) fraction from C. chinensis and in hexane (Hx) fraction from S. incisa, whereas inhibitory activities of W. subssilis were broadly seen in non-polar solvent fractions such as Hx, MC and EtOAc. Therefore, our results suggest that extracts from C. orbiculatus, C. chinensis, S. incisa and W. subsessilis may be developed as a therapeutic remedy against $TNF-{\alpha}-mediated$ diseases such as rheumatoid arthritis or further fractionated to isolate active components having $antiTNF-{\alpha}$ inhibitory activity.

• Journal of Microbiology and Biotechnology
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• v.13 no.5
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• pp.706-709
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• 2003

Ginsenosides and polysaccharides were isolated from Panax ginseng C.A. Meyer (Family Araliaceae) by treating at low ($60^{\circ}C$, LT), mild ($100^{\circ}C$, MT), and high ($120^{\circ}C$, HT) temperatures, and their inhibitory effects on growth, infection, and VacA vacuolation of Helicobacter pylori (HP) were investigated. The molecular weights of polysaccharides decreased as the processing temperature increased. Ginseng polysaccharides inhibited the HP infection into KATO III cells, but did not inhibit growth of HP and VacA vacuolation of HeLa cells. HT polysaccharides showed the most potent inhibition with $IC_50$ value of 6.8 mg/ml. Ginseng saponins did not inhibit the infection of HP into KATO cells. However, 20(s)-protopanaxadiol showed the most potent inhibition of HP growth and vacuolation of HeLa by VacA toxin with $IC_50$ values of 0.05 and 0.067 mg/ml, respectively.

• Korean Journal of Materials Research
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• v.9 no.12
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• pp.1155-1159
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• 1999

Thin film solar cells on a glass/$SnO_2$ substrate with p-SiC/i-Si/n-Si heterojunction structures were fabricated using a plasma-enhanced chemical-vapor deposition system. The photovoltaic properties of the solar cells were examined with varying the gas phase composition, x=$CH_4/\;(SiH_4+CH_4)$, during the deposition of the p-SiC layer. In the range of x=0~0.4, the efficiency of solar cell increased because of the increased band gap of the p-SiC window layer. Further increase in the gas phase composition, however, led to a decrease in the cell efficiency probably due to in the increased composition mismatch at the p-SiC/i-Si layers. As a result, the efficiency of a glass/$SnO_2$/p-SiC/i-SiC/i-Si/n-Si/Ag thin film solar cell with $1cm^2$ area was 8.6% ($V_{oc}$=0.85V, $J_{sc}$=16.42mA/$cm^2$, FF=0.615) under 100mW/$cm^2$ light intensity.

• Preventive Nutrition and Food Science
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• v.12 no.2
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• pp.84-88
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• 2007

In this study, we investigated antimutagenic and anticancer activities of leaf mustard (LM, Brassica juncea) and leaf mustard kimchi (LMK) during their fermentation period. Methanol extracts were prepared from raw mustard, brined leaf mustard in 10% Gueun salt solution for 2 hrs, leaf mustard fermented at 15$^{\circ}C$ for 5 days after brined in 10% Guenun salt solution for 2 hrs (Fr-LM), fresh leaf mustard kimchi (Fresh-LMK) and optimally ripened leaf mustard kimchi fermented at 5$^{\circ}C$ for 30 days (OR-LMK). OR-LMK showed the strongest inhibitory activities against the mutagenicities induced by aflatoxin B1 in Salmonella Typhimurium TA100. LMs and LMKs inhibited the survival or growth of AGS human gastric adenocarcinoma cells and HT-29 human colon carcinoma cells in MTT assay and growth inhibition test. Among the extracts, OR-LMK and FR-LM exhibited strong antiproliferative effect against cancer cells, especially HT-29 cells. DAPI staining assay showed that OR-LMK induced apoptosis cell death of HT-29 cells in a dose-dependent manner. These results suggest that leaf mustards and leaf mustard kimchi have chemopreventive activities.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.29 no.1
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• pp.151-167
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• 2003

Melanin biosynthesis is a human defense mechanism to protect skin from UV irradiation and also determines colors of hair and skin. However, as a interest on skin-whitening increases, researches to prevent pigmentation and hypersynthesis of melanin in skin are being actively in progress. Active components used as a whitening agent in cosmeceuticals are kojic acid, arbutin, vitamin C and hydroquinone. However, until now, because comparison researches among them in the aspect of both melanin formation and cellular toxicity have not been performed, we can't exactly estimate merits and defects of them as a whitening agent. To this end, we performed experiments to compare their effects on cell viability and melanin formation. As a first step, in vitro tyrosinase inhibition assay was done. While kojic acid and hydroquinone showed strong inhibition activities(their IC$\_$50/s are all < 100uM), arbutin and vitamin C showed weak activities. IC$\_$50/s of arbutin and vitamin C are 100uM and 400∼500uM, respectively. In B16BL6 melanoma cells, like in vitro tyrosinase inhibition assay, arbutin and kojic acid showed more strong inhibition effect on melanin synthesis than vitamin C. And unlike arbutin, vitamin C and kojic acid induced cell death at high concentration. Although arbutin showed no cytotoxicity, it has side effect to induce morphological change at high concentration.. In this paper, we suggest both kojic acid and arbutin have stronger ability to inhibit melanogenesis than vitamin C. And they also have side effect, that is, kojic acid induces cell death like vitamin C and arbutin changes cell morphology respectively.

• BMB Reports
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• v.42 no.2
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• pp.96-100
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• 2009

Aromatic (ar)-turmerone from turmeric oil displays anti-tumorigenesis activity that includes inhibited cell proliferation. This study investigated ar-turmerone-mediated apoptotic protein activation in human lymphoma U937 cells. Ar-turmerone treatment inhibited U937 cell viability in a concentration-dependent fashion, with inhibition exceeding 84%. Moreover, the treatment produced nucleosomal DNA fragmentation and the percentage of sub-diploid cells increased in a concentration-dependent manner; both are hallmarks of apoptosis. The apoptotic effect of ar-turmerone was associated with the induction of Bax and p53 proteins, rather than Bcl-2 and p21. Activation of mitochondrial cytochrome c and caspase-3 demonstrated that the activation of caspases accompanied the apoptotic effect of ar-turmerone, which mediated cell death. These results suggest that the apoptotic effect of ar-turmerone on U937 cells may involve caspase-3 activation through the induction of Bax and p53, rather than Bcl-2 and p21.

• The Korean Journal of Cytopathology
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• v.9 no.1
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• pp.89-94
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• 1998

A case of fine needle aspiration cytology of an osteoclastic giant cell tumor of pancreas, which is an uncommon variant of ductal adenocarcinoma, is described. Aspirated tumor cells were characterized by three populations: (1) bland osteoclast like giant cells with multiple small, round nuclei with distinct nucleoli, and abundant cytoplasm, (2) Individually scattered or loosely clustered medium sized mononuclear tumor cells, having fine chromatin, smooth nuclear membrane, often prominent nucleoli, and high N/C ratio, (3) bland or atypical spindle shaped cells. Osteoid like lacy material was also seen on cell block section. The immunohistochemical studies using paraffin embedded cell block section showed positivities for vimentin and lysozyme in both giant and mononuclear turner cells. However, they were negative for cytokeratin, epithelial membrane antigen, S-100 protein, carcinoembryonic antigen, and p53.

• BMB Reports
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• v.49 no.10
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• pp.566-571
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• 2016

Forskolin (FSK), an adenylyl cyclase activator, has recently been shown to enhance nucleotide excision repair (NER) upon UV exposure. However, our study revealed that this effect was detected in human skin epithelial ARPE19 cells only in growing cells, but not in non-cycling cells. When the cells were grown at low density (70% confluence), FSK was capable of stimulating cAMP responsive element binding (CREB) phosphorylation, a marker for FSK-stimulated PKA activation, and resulted in a significant increase of NER activity compared to control treatment. However, cells grown under 100% confluent conditions showed neither FSK-induced CREB phosphorylation nor the resulting NER enhancement. These findings indicate that cellular growth is critical for FSK-induced NER enhancement and suggest that cellular growth conditions should be considered as a variable while evaluating a reagent's pharmacotherapeutic efficacy.

• The Journal of the Korean Society for Microbiology
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• v.21 no.4
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• pp.455-460
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• 1986

This study was undertaken to investigate to know whether spleen and lymph node cells from immunized mice can transfer systemically the delayed-type hypersensitivity(DTH) reaction to Salmonella typhimurium and to characterize the lymphoid cells using glass, nylon wool and rabbit anti-mouse thymocyte serum. Mice, C57BL/6 or ICR, were immunized subcutaneously at 11, 8 and 2 days before adoptive systemic transfer with $100{\mu}g$ of protein antigen from S. typhimurium in complete Freund adjuvant. It was found that DTH reaction to S. typhimurium could be transferred to normal recipient systemically by both spleen and lymph node cells($10^8\;cells$, respectively) from immunized mice. The cells responsible for this transfer of DTH reaction were glass nonadherent T lymphocytes.