• Title/Summary/Keyword: Chung-Ju

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Chemical Properties of Insulation Paper in oil after Thermal Aging (열 열화에 따른 유입절연지의 화학적 특성)

  • Kim, Pil-Hwan;Kim, Jae-Hoon;Kim, Ju-Han;Lee, Won-Yeong;Han, Sang-Ok
    • Proceedings of the KIEE Conference
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    • 2004.11d
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    • pp.77-79
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    • 2004
  • It is caused that insulation paper, which had got a lot of thermal stress by over-load after installation, should have been deteriorated in electrical and mechanical characteristics. Beside, insulation material is decreased the insulating property and accelerated aging of them in case of dielectric loss when transformers are manufactured with some moisture or transformers would have been them because of moisture-permeation. Therefore, in this study we experienced the influence of moisture content in case of the thermal aged insulation paper. we have measured tan 6 and breakdown voltage in the ratio of paper' moisture content before the aging and then taken the same tests again after insulation paper thermally accelerating-aged. There is a purpose to gain data for a life-design and to establish aging mechanism in order to continuously study life expectancy of the insulation paper

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Application of Metabolomics to Quality Control of Natural Product Derived Medicines

  • Lee, Kyung-Min;Jeon, Jun-Yeong;Lee, Byeong-Ju;Lee, Hwanhui;Choi, Hyung-Kyoon
    • Biomolecules & Therapeutics
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    • v.25 no.6
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    • pp.559-568
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    • 2017
  • Metabolomics has been used as a powerful tool for the analysis and quality assessment of the natural product (NP)-derived medicines. It is increasingly being used in the quality control and standardization of NP-derived medicines because they are composed of hundreds of natural compounds. The most common techniques that are used in metabolomics consist of NMR, GC-MS, and LC-MS in combination with multivariate statistical analyses including principal components analysis (PCA) and partial least squares-discriminant analysis (PLS-DA). Currently, the quality control of the NP-derived medicines is usually conducted using HPLC and is specified by one or two indicators. To create a superior quality control framework and avoid adulterated drugs, it is necessary to be able to determine and establish standards based on multiple ingredients using metabolic profiling and fingerprinting. Therefore, the application of various analytical tools in the quality control of NP-derived medicines forms the major part of this review. $Veregen^{(R)}$ (Medigene AG, Planegg/Martinsried, Germany), which is the first botanical prescription drug approved by US Food and Drug Administration, is reviewed as an example that will hopefully provide future directions and perspectives on metabolomics technologies available for the quality control of NP-derived medicines.

Inhibition of Aldose Reductase on Rat Lens by Tartary Buckwheat

  • Mok, So-Youn;Lee, Jeong-Min;Kim, Hye-Min;Lee, Dong-Gu;Yoon, Young-Ho;Cho, Eun-Ju;Lee, Sang-Hyun
    • Natural Product Sciences
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    • v.17 no.3
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    • pp.230-233
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    • 2011
  • To evaluate the potential of naturally occurring aldose reductase (AR) inhibitors from food material, MeOH extract and stepwise polarity fractions from tartary buckwheat and two common Korean buckwheat cultivars, yangjul-maemil and daesan-maemil, were tested on AR inhibition in rat lens in vitro. The EtOAc fraction from tartary buckwheat exhibited good AR inhibitory activity ($IC_{50}$ value, $8.19\;{\mu}g$/ml). A portion of the EtOAc fraction from tartary buckwheat led to the isolation of rutin by MeOH recrystalization. Rutin exhibited good AR inhibitory activity ($IC_{50}$ value, $9.28\;{\mu}M$). These results suggest that tartary buckwheat could be a useful food material in the development of a novel AR inhibitory agent against diabetic complications.

Benzodiazepine System is Involved in Hyperalgesia in Rats Induced by the Exposure to Extremely Low Frequency Magnetic Fields

  • Jeong Ji Hoon;Choi Kyung Bum;Moon Nam Ju;Park Eon Sub;Sohn Uy Dong
    • Archives of Pharmacal Research
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    • v.28 no.2
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    • pp.238-242
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    • 2005
  • Many reports demonstrate that extremely low frequency magnetic fields (ELF MFs, 60 Hz) may be involved in hyperalgesia. In a previous investigation, we suggested that MFs may produce hyperalgesia and such a response may be regulated by the benzodiazepine system. In order to further confirm this effect of MFs, we used diazepam and/or flumazenil with MFs exposure. When testing the pain threshold of rats using hot plate tests, MFs or diazepam ($0.5\;{\mu}g$, i.c.v.; a benzodiazepine receptor agonist) induced hyperalgesic effects with the reduction of latency. These effects were blocked by a pretreatment of flumazenil (1.5 mg/kg, i.p.; a benzodiazepine receptor antagonist). When the rats were exposed simultaneously to MFs and diazepam, the latency tended to decrease without statistical significance. The induction of hyperalgesia by co-exposure to MFs and diazepam was also blocked by flumazenil. However, the pretreatment of GABA receptor antagonists such as bicuculline ($0.1\;{\mu}g$, i.c.v.; a $GABA_A$ antagonist) or phaclofen ($10\;{\mu}g$, i.c.v.; a $GABA_B$ antagonist) did not antagonize the hyperalgesic effect of MFs. These results suggest that the benzodiazepine system may be involved in MFs-induced hyperalgesia.

Development of a DSP based Decoder for High-definition Video/Audio System (DSP 기반 HD급 비디오/오디오 디코더 시스템 개발)

  • Park, Young-Keun;Kim, Bong-Ju;Kim, Byeong-Il;Kim, Jung-Keun;Chang, Tae-Gyu;Lee, Jun-Woo
    • Proceedings of the KIEE Conference
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    • 2003.07d
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    • pp.2681-2683
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    • 2003
  • 본 논문에서는 HDTV(High Definition TV) 방송수신을 위한 DSP기반의 HD급 비디오/오디오 디코더 시스템을 개발하고 그 성능을 확인하였다. DSP 플랫폼은 TI사의 TMS320C6415를 대상으로 하였으며 TI의 DSP RTOS인 DSP/BIOS를 이용하여 방송스트림인 TS (Transport Stream)을 분리하기 위한 TS Demuxer, MPEC-2 비디오 디코더 및 AC-3 오디오 디코더 알고리즘을 통합하였으며, 각각의 알고리즘은 대상 DSP 플랫폼인 TMS320C64x에 맞게 고정소수점 구조화 및 최적화를 실시하였다. 테스트를 위한 시스템은 스트리밍을 위한 호스트 PC와 PCI버스를 통해 연결된 DSP보드로 구성하였으며 실제 HDTV방송용 스트림과 SD급 스트림을 이용하여 성능을 확인하였다.

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Inhibitory activity of methanol extracts from different colored flowers on aldose reductase and HPLC-UV analysis of quercetin

  • Quilantang, Norman G.;Ryu, Seo Hyun;Park, Se Hoon;Byun, Jae Sang;Chun, Je Sung;Lee, Ju Sung;Rodriguez, Joyce P.;Yun, Young-Seok;Jacinto, Sonia D.;Lee, Sanghyun
    • Horticulture, Environment, and Biotechnology : HEB
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    • v.59 no.6
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    • pp.899-907
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    • 2018
  • The methanol extracts of flowers obtained from 67 plant species were screened for their inhibitory activity on aldose reductase (AR). Alnus japonica, Aster spathulifolius, Chionanthus retusus, Morus bombycis, Crysanthemum boreale, Persicaria tinctoria, Platycarya strobilacea, and Serratula coronata var. insularis exhibited potent aldose reductase inhibitory (ARI) activity. HPLC-UV analysis of quercetin, an AR inhibitory flavonoid, was performed on extracts showing strong ARI activity. Quercetin was detected in C. retusus, C. boreale, P. tinctoria, and S. coronata var. insularis at concentrations of 1.33, 1.56, 0.82, and $3.37mg\;g^{-1}$ extract, respectively, indicating that quercetin contributed to the ARI activity of these extracts. In the samples in which quercetin was absent, other compounds may be responsible for their potent ARI activity. These results serve as a basis for further studies regarding the bioactive components responsible for the inhibitory effects of various flower extracts on AR activity.

The Interkingdom Interaction with Staphylococcus Influences the Antifungal Susceptibility of the Cutaneous Fungus Malassezia

  • Juan Yang;Sungmin Park;Hyun Ju Kim;Sang Jun Lee;Won Hee Jung
    • Journal of Microbiology and Biotechnology
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    • v.33 no.2
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    • pp.180-187
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    • 2023
  • The skin is a dynamic ecosystem on which diverse microbes reside. The interkingdom interaction between microbial species in the skin microbiota is thought to influence the health and disease of the skin although the roles of the intra- and interkingdom interactions remain to be elucidated. In this context, the interactions between Malassezia and Staphylococcus, the most dominant microorganisms in the skin microbiota, have gained attention. This study investigated how the interaction between Malassezia and Staphylococcus affected the antifungal susceptibility of the fungus to the azole antifungal drug ketoconazole. The susceptibility was significantly decreased when Malassezia was co-cultured with Staphylococcus. We found that acidification of the environment by organic acids produced by Staphylococcus influenced the decrease of the ketoconazole susceptibility of M. restricta in the co-culturing condition. Furthermore, our data demonstrated that the significant increased ergosterol content and cell membrane and wall thickness of the M. restricta cells grown in the acidic environment may be the main cause of the altered azole susceptibility of the fungus. Overall, our study suggests that the interaction between Malassezia and Staphylococcus influences the antifungal susceptibility of the fungus and that pH has a critical role in the polymicrobial interaction in the skin environment.

Edge Weight Prediction Using Neural Networks for Predicting Geographical Scope of Enterprises (입지선정 범위 예측을 위한 신경망 기반의 엣지 가중치 예측)

  • Ko, JeongRyun;Jeon, Hyeon-Ju;Jeon, Joshua;Yoon, Jeong-seop;Jung, Jason J.;Kim, Bonggil
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2021.05a
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    • pp.22-24
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    • 2021
  • This paper is a proposal for edge weight prediction using neural networks to graph configurations of nodes and edges. Brand is one of the components of society. and one of the brand's most important strategies is geographical location strategy. This paper is focus on that strategy. In This paper propose two things: 1) Graph Configuration. node consists of brand store, edge consists of store-to-store relationships and edge weight consists of actual walk and drive distance values. 2) numbering edges and training neural networks to predict next store distance values. It is expected to be useful in analyzing successful brand geographical location strategies.

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A report of 21 unrecorded bacterial species belonging to the phyla Bacillota and Verrucomicrobiota in Korea

  • Jae Kyeong Lee;Ju Hye Baek;Jung-Hoon Yoon;Chang-Jun Cha;Wonyong Kim;Myung Kyum Kim;Taegun Seo;Che Ok Jeon
    • Journal of Species Research
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    • v.12 no.spc2
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    • pp.15-22
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    • 2023
  • During a comprehensive investigation of indigenous prokaryotic species in Korea, 20 and one bacterial strains assigned to the phyla Bacillota and Verrucomicrobiota, respectively, were isolated from diverse environmental habitats, including soil, mud, tidal flat, seawater, sand, sediment, brackish water, and healthy human urine. Based on their high 16S rRNA gene sequence similarities (>98.7%) and the formation of robust phylogenetic clades with their closest related reported species, each strain was assigned to an independent and predefined bacterial species. Since there were no published or official reports regarding these 21 isolates in Korea, they - 20 species of four families in two orders of the phylum Bacillota and one species of the phylum Verrucomicrobiota - have been reported as unrecorded species in Korea. In addition, Gram staining, colony and cell morphology, basic biochemical characteristic, isolation source, and strain ID of each species are also described in the species description sections.

A Design System for Group Management and Maintenance of Reliability In Hybrid P2P (Hybrid P2P의 그룹관리와 신뢰성을 위한 시스템 설계)

  • Lee, Seok-Hee;Hyun, Jeung-Sik;Lee, Tae-Hee;Cho, Sang
    • Proceedings of the Korean Information Science Society Conference
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    • 2002.04a
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    • pp.412-414
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    • 2002
  • 현재 많이 사용되고 있는 P2P개념으로는 순수 P2P와 변경 P2P구조가 있다[3]. 순수 P2P의 모델에는 Gnutella와 stella등의 형태가 존재하고 변형 P2P로는 무수히 많은 형태가 존재한다. 이 변형 P2P모델들 중파일 공유 모델들이 존재하는데 이 모델들은 파일의 공유를 위한 그룹 관리와 검색, 색인 등의 기능을 제공한다. 파일공유 모델의 Peer들에 대해 연결성 유지를 위한 많은 부하와 사용자에 있어서 그룹에 대한 형태의 문제점 그리고 서버의 Fail에 대한 비연결성에 관한 문제점을 해결하기 위해 본 논문에서는 라우팅 기법에서의 접근을 통해 과일공유모델에 계층적 구조를 적용하고 Backup시스템을 설계하여 사용자에 의한 효율적인 그룹관리와 연결의 신뢰성을 유지하기 위해 시스템을 설계하였다.

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