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HVDC계통에서 동기조상기의 파라미터 선정에 관한 연구
이석진(Seok-Jin Lee),이홍재(Heung-Jae Lee) 대한전기학회 2010 전기학회논문지 Vol.59 No.8
This paper presents the determination of synchronous compensator(S.C) rating and parameter in Cheju AC network. The role of S.C is to supply Inertia and reactive power to HVDC system which is a kind of a generator without the function of reactive power control and Inertia. Therefore, the parameters of S,C have to be determined by considering HVDC operating characteristics. The background of this paper is the determination of S.C parameters in Cheju AC network in the case of replacing current operating S,C to new S.C type.
윤기중(Ki Jung Yun),김유림(Yu Rim Kim),이홍재(Heung Jae Lee),김경숙(Kyoung Suk Kim),권영미(Young-Mi Kwon),최민규(Min Kyu Choi),오재민(JaeMin Oh),정연태(Yeun Tai Chung) 대한해부학회 2004 Anatomy & Cell Biology Vol.37 No.6
HO-1은 스트레스에 의해 유도되는 효소로 그 항염증작용에 대한 기전은 거의 밝혀지지 않고 있다. NF-κB 활성은 만성 염증성 대장염을 일으키는데 관여하는 매우 중요한 인자이다. 우리는 대장염에서 NF-κB 활성과 HO-1 사이의 관계에 대하여 조사하였다. 정상인에 비하여 염증성 대장염이나 acute pesudomembranous colitis를 가진 환자에서 대장의 상피조직의 HO-1의 발현이 현저히 감소하였다. 또한 사람 대장상피세포주인 HT-29세포에서 TNF-α와 IL-1β 등의 사이토카인들은 HO-1의 발현을 억제하였다. HO-1의 유도제인 CoPPIX는 TNF-α에 의한 NF-κB 활성을 억제하였다. 또한 HO-1의 대사물질인 일산화탄소와 빌리루빈 역시 TNF-α에 의한 NF-κB 활성을 억제하였다. 그러나 다른 대사물질인 철은 TNF-α에 의한 NF-κB 활성을 억제하는데 아무런 효과가 없었다. 재미있게도 CoPPIX는 TNBS에 의해 유도된 만성 대장염을 현저히 개선하였고 궤양성 대장염의 동물모델에서도 NF-κB 활성을 억제하였다. 이상의 결과로 CoPPIX는 NF-κB 활성의 억제를 통해서 TNBS에 의해 유도된 만성 대장염의 증상들을 개선시킨다고 생각되었고 HO-1은 만성 염증성 대장염을 치료하는데 중요한 타겟물질이라고 생각하였다. Heme oxygenase-1 (HO-1) is a stress-inducible enzyme with anti-inflammatory activity, but the mechanisms underlying this activity are incompletely understood. Nuclear transcription factor κB (NF-κB) activation is an important factor in the pathogenesis of inflammatory bowel disease (IBD). We investigated the suppressive effects of HO-1 on the activation of NF-κB by pro-inflammatory cytokines in cultured colonic epithelial cells and by trinitrobenzene sulfonic acid (TNBS) in the colon of mice. The expression level of HO-1 in the colonic epithelium of a patient with inflammatory bowel disease and pseudomembranous colitis was lower than that in a healthy control subject. In cultured human colonic epithelial HT-29 cells, pro-inflammatory cytokines such as tumor necrosis factor-α (TNF-α) and IL-1β down-regulate HO-1 expression. The HO-1 inducer, cobalt protoporphyrin IX (CoPPIX), dramatically down-regulated NF-κB activation in HT-29 cells by TNF-α. In addition, bilirubin-a product of heme catabolism by HO-1-and the carbon monoxide donor tricarbonyldichlororuthenium (II) dimer also suppressed NF-κB activation by TNF-α. However, iron, another heme metabolite, did not suppress NF-κB activation by TNF-α. Furthermore, CoPPIX diminished the macroscopic and histopathological symptoms of TNBS-induced colitis and down-regulated NF-κB activation in mice. In conclusion, this study suggests that HO-1 plays an important role in the down-regulation of NF-κB activation, which is a key factor in the pathogenesis of IBD and is thus an excellent therapeutic target for the treatment of IBD.
김우성,이선화,김상엽,정동윤,김재이,이영자,이홍재,정성욱,박흥재 한국환경과학회 2003 한국환경과학회지 Vol.12 No.10
Pesticides were extracted from samples with 70% acetone and methylene chloride in order, and then cleaned up via open-column chromatography apparatus packed with fiorisil, and finally analyzed simultaneously the organophosphorus pesticides using GC/NPD, Ultra-2 and Ultra-1 fused silica capillary columns were used to separate and identify the products. Recovery of most analytes from soybean sample, taken from pesticide residues well, was greater than(80%) for all except(6) analytes. This method can simultaneously determine multiple pesticides with a high degree of accuracy and precision.