• Journal of the Korean Applied Science and Technology
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• v.38 no.5
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• pp.1249-1254
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• 2021

UV induce oxidative stress and increase matrix metalloproteinase (MMP) expression, resulting in skin aging. Thus, preventing skin damage from ultraviolet B (UVB)-induced skin damage can attenuate skin aging. Spirulina is comprised of prokaryotes a powerful antioxidant. This study aimed to investigate the photoprotective effects of spirulina-derived phycocyanin (PC) against UVB radiation using human skin fibroblast. As a results, PC showed no toxicity at concentrations of 5-40 ㎍/mL in terms of fibroblast viability. Survival rate of UVB-irradiated fibroblast incresased to 73.5% from 50.5% with PC treatment. UVB treatment increased MMP-1 and MMP-9 expression whereas PC treatment decreased it. The results indicate that PC might reduce or prevent skin aging by reducing UVB irradiation-induced skin wrinkles and free radicals.

• The Korean Journal of Cytopathology
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• v.5 no.1
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• pp.1-9
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• 1994

The cytological and ultrastructural findings of Pneumocystis carinii(PC) obtained from rats by bronchoalveolar lavage (BAL) are described. All developmental forms of the PC organisms were obtained in the lavage fluid. Papanicolaou stain revealed conglomeration of PC as a foamy cast. The cystic walls of PC were well identified on Gomori's methenamine silver stain. Trophozoites and intracystic bodies were stained by Giemsa and Diff-Quik techniques. Some PC organisms were seen within the alveolar macrophages. Ultrastructurally, the cysts were almost circular in shape, and were nearly devoid of surface tubular extensions. The wall of the cyst was composed of an unit membrane, an intermediate electron lucent layer and an external electron dense layer The cysts frequently contained intracystic bodies, so called sporozoites. Occasionally empty or collapsed cysts with no intracystic bodies, and precysts were found. Trophozoites were variable in size and shape with abundant tubular extensions along the single electron dense pellicle. BAL is a useful method for concentrating the various morphologic forms of PC organisms, and is a rapid diagnostic method for PC pneumonia.

• KSBB Journal
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• v.28 no.1
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• pp.13-17
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• 2013

In this study, we investigated the anti-inflammation effect of Potentilla chinensis (PC) on Raw264.7 macrophage cells. Ethanol extract of PC decreased the production of nitric oxide (NO) in LPS-stimulated RAW264.7 cells. Ethanol extract was fractioned by n-hexane, chloroform, ethyl acetate, n-butanol, water and each fraction was tested for inhibitory effects on inflammation. Among the sequential solvent fractions, PC chloroform extracts (50, 100, 300, and 500 ${\mu}g/mL$) significantly suppressed LPS-stimulated production of NO. During the entire experimental period, 200 and 300 ${\mu}g/mL$ of PC chloroform extracts had no cytotoxicity. LPS-induced NO and prostaglandin $E_2$ ($PGE_2$) production were inhibited by PC chloroform extracts up to 50% and 90% of these productions, respectively. PC chloroform extracts reduced the expression of iNOS and COX-2 gene. These results suggest that PC chloroform extracts exhibit strong effects of anti-inflammation and can be a potential candidate in the treatment of acute and chronic inflammatory diseases.

• Journal of KIISE:Computer Systems and Theory
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• v.29 no.2
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• pp.57-64
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• 2002

We implemented two fast PC clusters using fast PCs and high speed network. First. we built the first generation of 16 PC cluster and have used it for real-time operation at Cheju Regional Meteorological Office. Next, we built the second generation of 16PC with dual CUs cluster which was efficiently improved based on performance analysis of the first generation of cluster. In this research we also analyzed performance of two different clusters, which have different CPUs and communication devices using the parallel model MM5 which has been used for the real-time weather forecasting.

• Journal of Applied Biological Chemistry
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• v.64 no.3
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• pp.237-244
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• 2021

Camellia sinensis, Green tea, contains phenolic compounds that act to scavenge reactive oxygen species (ROS), such as catechin, epicatechin, etc. In contrast with the tea leaf, the bioactivity of its fruit and the fruit peels remains still unclear. This study focused on the effects of fruit and fruit peels of C. sinensis (FC and PC) against oxidative DNA damage in NIH/3T3 cells. The scavenging effects of FC and PC on ROS were assessed using 1,1-diphenyl-2-picryl hydrazyl or 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid radicals. The measurement of ROS in cellular levels was conducted by DCFDA reagent and the protein expression of γ-H2AX, H2AX, cleaved caspase-3, p53, and, p-p53 was analyzed by immunoblotting. The gene expressions of p53 and H2AX were assessed using polymerase chain reaction techniques. The major metabolites of FC and PC were quantitatively measured analyzed and the amounts of phenolic compounds and flavonoids in PC were greater than those in FC. Further, PC suppressed ROS production, which protects the oxidative stress-induced DNA damage through reducing H2AX, p53, and caspase-3 phosphorylation. These results refer that the protective effects of FC and PC are mediated by inhibition of p53 signaling pathways, probably via the bioactivity of phenolic compounds. Thus, FC and PC can serve as a potential antioxidant in DNA damage-associated diseases.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.31 no.1
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• pp.61-71
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• 2021

Instant messengers are a means of communication for modern people and can be used with smartphones and PCs respectively or connected with each other. Messengers, which provide various functions such as message, call, and file sharing, contain user behavior information regarded as important evidence in forensic investigation. However, it is difficult to analyze as well as acquire smartphone data because of the security of smartphones or apps. However, messenger data can be extracted through PC when the messenger is used on PC. In this paper, we obtained the credential data of Wire messenger in Windows 10, and showed that it is possible to log-in from another PC without authentication. In addition, we identified and classified major artifacts generated based on user behavior.

• Polymer(Korea)
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• v.39 no.1
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• pp.71-77
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• 2015

We synthesized a low band gap alternating copolymer containing electron-rich units (i.e. dithienosiloles and benzodithiophenes) and electron-deficient units (i.e. difluorobenzothiadiazoles) for high performance organic solar cells. The polymer was prepared by the Stille coupling reaction and characterized using $^1H$ NMR, GPC, TGA, UV-visible absorption spectroscopy, and cyclic voltammetry. Solar cells were fabricated in a structure of ITO/PEDOT:PSS/polymer: $PC_{70}BM/Al$ with five different blending ratios of polymer and $PC_{70}BM$ (1:1.5, 1:2, 1:3, 1:3.5 and 1:4 by weight ratio). The best efficiency was achieved from the 1:3 ratio of polymer and $PC_{70}BM$ in the photoactive layer, and TEM revealed that there is an optimal nanoscale phase separation between polymer and $PC_{70}BM$ in the 1:3 ratio blend film.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2012.05a
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• pp.213-215
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• 2012

The current Navigation System for the Visually Impaired Person has a short and limited communication distance and can't receive enough information from Visually Impaired Person to assist directly. In addition, because the path is dangerous and incomplete for the Visually Impaired Person, moving with White Stick is still inconvenient and dangerous. To solve this problem we implement communication that can send and receive video, voice, location information between the Visually Impaired Person's Android platform and assistant's PC.

• 한국신재생에너지학회:학술대회논문집
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• 2011.11a
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• pp.59.1-59.1
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• 2011

BSF 후면전계효과는 태양전지의 개방전압 증가를 결정하며 효율에 매우 중요한 요인이다. 본 연구에서는 p-type에서의 후면전계효과를 확인하기 위해 PC1D 시뮬레이션(Simulation)을 통해 p+ 영역의 표면농도와 깊이에 따른 전기적 특성을 분석 하였다. 최적효율을 찾기위해 면저항을 $30{\Omega}/{\square}$으로 고정하고 깊이와 표면 농도값을 가변하였다. 최적화 결과 표면농도값이 작아지고 깊이가 커질수록 효율이 좋아지는 경향이 나타났으며 Peak doping=$5{\times}10^{18}cm^{-3}$, Juction depth=12.52um에서 최고효율 19.14%를 얻을 수 있었다. 본 시뮬레이션을 바탕으로 실제 태양전지 제작 과정에 적용 가능하다. p-type 태양전지 제작에서 후면의 p+ 영역의 깊이를 증가시키고, 표면 농도를 낮추는 공정을 통해 효율향상을 기대 할 수 있다.

• Bulletin of the Korean Chemical Society
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• v.9 no.2
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• pp.98-101
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• 1988

A pure columnar cholesterogen based on the octasubstituted phthalocyanine $(PcH_2)$, S-(+)-2, 3, 9, 10, 16, 17, 23, 24-octakis[5-(dodecyloxy)-2-oxa-pentyl]-phthalocy anine(1a), is described. To evaluate a cholesteric character of 1a, the corresponding achiral $PcH_2$ 1b and the copper complex of chiral $PcH_2$ 1a (CuPc), S-(+)-2,3,9,10,16,17,23,24-octakis[4-(dodecyloxy)- 2-oxapentyl]-phthalocyanine(2a) were also prepared. The chiral 1a exhibited a typical cholesteric texture change in which the transition of platelet (blue phase) to fan-shape texture was observed (K－M－I), whereas the corresponding achiral 1b showed only a focal conic texture (K－ M－I). This is the first instance of a pure columnar cholesterogen observed with discotic liquid crystal systems.