수공구조물이 하천환경에 미치는 영향에 관한 연구(I) : 수리학적특성 Hydraulic Characteristics

안승섭,최윤영,이수식 한국환경과학회 2002 한국환경과학회지 Vol.11 No.3

In this study, water protection reservoir is selected as the target which is located at the estuary of Teahwa river to analyze and examine the effects of hydraulic structure on river environment. This study aims at the definition of factors which cause the change of ecological environment of river due to the effects of the sediment protection reservoir, and the proposal of the direction of environmental friendly river space development through the analysis and examination of stream variation conditions and riverbed variation characteristics among many effects of hydraulic structure on river environment before and after removal of the sediment protection reservoir when design flow is yielded. Firstly, in case of removal the existing sediment protection reservoir, the hydraulic variation characteristics like depth drop due to removal of the sediment protection reservoir are thought of little because it is examined that depths drop with about 0.01m and 0.01~0.56m when low flow is yielded and design flood yielded, respectively. Nextly, as the examination result of the variation characteristics of flow velocity in case of removal the existing sediment protection reservoir, it is thought that the concern about riverbed erosion is not serious according to the analyzed result as the mean velocity of the channel section where the velocity varies in case of removal the sediment protection reservoir is about 0.07~1.36m/s when low flow is yielded, and is about 1.02~2.41m/s when design flood is yielded despite riverbed erosion is concerned as it is examined that flow velocity is getting increase as about 0.01m/s when low flow is yielded and about 0.01~0.44m/s when design flood is yielded. Lastly, from the prediction result of riverbed variation for each flow amount condition before and after removal the sediment protection reservoir, it is known that the variation range of riverbed is nearly constant when flow amount of the channel exceeds a specific limit as it is analyzed that the more flow amount, the more erosion and sediment in the channel section of down stream part of the sediment protection reservoir and the sediment protection reservoir-Samho-gyo, and the variation ranges according to flow amount between flood condition and design flood condition have little difference in the channel section of the upstream of Samho-gyo.

수공구조물이 하천환경에 미치는 영향에 관한 연구(II) : 수질 및 생태학적특성 Water Quality and Ecological Characteristics

안승섭,최윤영,이수식 한국환경과학회 2002 한국환경과학회지 Vol.11 No.4

In this study, water protection reservoir is selected as the target which is located at the estuary of Taehwa river to analyze and examine the effects of hydraulic structure on river environment. This study examined the water quality variation characteristics among many effects of hydraulic structure on river environment before and after removal of the sediment protection reservoir when low flow is yielded. This study aims at the definition of factors which cause the change of ecological environmental friendly river space development through the comparison of stream variation conditions(depth, velocity, and etc.) and riverbed variation characteristics with ecological depth condition of Taehwa-river's channel for each representative species of fish and examination those. Firstly, form the examination result of water quality when low flow is yielded before and after removal of the sediment protection reservoir for problems about water quality of river due to flow amount decrease in river, it is found that DO decreases about 0.78~0.86ppm at the lower stream of Myeongchon-gyo, and BOD decreases about 0.06~0.24ppm from right upper stream to the direction of estuary when the sediment protection reservoir is removed. It is known from the above that there is some improvement of water quality from the lower stream of Taehwa-gyo to the estuary in case of removal the sediment protection reservoir. Nextly, it is thought that the effects on ecosystem due to water depth and draw down in channel is not serious on the basis of the examination of water quality analysis result according to removal of sediment protection reservoir and hydraulic depths for reservation of ecosystem, these are 10~40㎝ for breeding season, 10~50㎝ for fry period, and 10~100㎝ for adult period of the representative species of fish in Korea.

Process Innovation Improves Trial Operation Efficiency

Choi, Yun Jung,Kim, Kyu-pyo,Park, Sumi,Park, MiYeon,Kim, Sulhwa,Kim, Younkyoung,Bae, Kyun-Seop,Beck, Sung-Ho,Choi, Ki-Eun,Chung, Jong Woo,Lim, Young–,Suk,Kim, Tae Won SAGE Publications 2016 Therapeutic innovation & regulatory science Vol.50 No.4

<P>Background: Despite the fact that unaddressed delays in clinical trial operation could severely compromise the overall effort invested, there seems to be a lack of concerted effort in reforming such delays. This study evaluated the composite effect of initiatives in reforming trial operation efficiency. Methods: A high-volume academic medical center in Korea has implemented various initiatives to improve the trial operation efficiency by expediting times from institutional review board (IRB) submission to approval, from IRB submission to trial open for subject enrollment, and from trial open to first patient-in. The initiatives include implementation of the protocol preliminary review, parallel processing of the clinical trial agreement review in line with the protocol submission to the IRB, and involvement of project manager for operational risk management. Times from IRB submission to approval, from IRB submission to trial open, and from trial open to first patient-in before and after implementation of initiatives were compared. Results: The median time required in IRB approval was meaningfully shorter in the postinitiative group (19 vs 14 days; P < .001). The median times from IRB submission to trial open for subject enrollment and from trial open to first patient-in were reduced significantly in the postinitiative group (trial open: 25 vs 18 days, P < .001; first patient-in: 111.5 vs 100 days, P = .014). Conclusions: The initiatives were effective in reforming trial operational efficiency. Additional studies to address the cause of operational delay and modifiable factors influencing subject enrollment are needed to further improve operational efficiency.</P>

Determination of Tolterodine in human plasma by Liquid chromatography-Electrospray Ionization Tandem Mass Spectrometry

PARK Young- Hwan,MOON Hae-Ran,LEE Eun-Hee,MOON Chul-Jin,CHOI Yun-Jung,LEE Young,CHOI Mi-Seop 대한약학회 2006 大韓藥學會 總會 및 學術大會 Vol.2006 No.2

PK/PD modeling for antiplatelet aggregation and cardiovascular effect of triflusal in human

Mi-seop Choi,Hwi-yeol Yun,Ji-eun Choi,Kwang-il Kwon 한국임상약학회 2005 학술대회 Vol.2005 No.1

간문부 담관암의 임상적 고찰

최연승(Yun-Seung Choi),이건영(Keon-Young Lee),안승익(Seung-Ik Ahn),최선근(Sun Keun Choi),허윤석(Yoon Seok Hur),송은섭(Eun-Seop Song),김세중(Sei Joong Kim),홍기천(Kee-Chun Hong),신석환(Seok-Hwan Shin),우제홍(Ze-Hong Woo) 한국간담췌외과학회 2003 한국간담췌외과학회지 Vol.7 No.1

사염화탄소 투여 흰쥐에서 간 섬유화 진행에 따른 propranolol의 약물동태지표와 간문맥-체순환 단락과의 관계

고동희,박근태,김정미,윤영섭,이성희,김동욱,김진배,최윤영,강주섭,최호순,함준수,이민호 대한간학회 2002 Clinical and Molecular Hepatology(대한간학회지) Vol.8 No.3

목적: 우리나라와 같이 만성 간 질환자가 많은 경우 약물 개발에 있어 임상 시험중에 만성 간질환자에 대한 제1c상의 시험이 필요하며 이를 위한 전 임상연구가 중요하다. 이에 본 저자는 이런 임상 시험 제1c상 시험의 전임상 연구에 도움을 주고자 사염화탄소 유발 간경변증 모델을 사용하여 간문맥- 체순환 단락을 알 수 있는 Thallium-201 per rectal scintigraphy와 propranolol의 약물동태학적 지표의 관련성을 알아보았다. 방법: 8주령의 실험군 흰쥐 (Sprague-Dawley계)를 대상으로(n=6) 올리브유에 녹인 10% 사염화탄소를 1 mL/㎏씩 주 2회 12주 동안 근육내 주사하여 간경변증을 유발시켰고, 정상 대조군(n=6)에 대해서는 12주 동안 동량의 올리브유만을 주 2회 근육내 주사하였다. 투여가 끝난 후 흰쥐는 감마카메라를 통해 Thallium-201 per rectal scintigraphy을 실행해 방사능 계수를 측정하여 심장/간 방사능 활동도(H/L ratio)를 구하였다. 각 군 의 흰쥐에 2 ㎎/㎏의 propranolol을 꼬리정맥을 통 해 단 회 투여하고 0.5, 1, 2 그리고 4시간 후의 혈중 농도를 역상 HPLC-형광기법에 의해 측정하였다. 시간대 혈중 농도 곡선을 작성하여 AUC, 초기 혈 중 농도, t1/2(β) 그리고 혈중 청소율 등의 약물동태학적 지표들을 계산하였다. 실험이 끝난 흰쥐는 심장 천자로 사혈 후 희생시켜 복부를 절개하여 간 조직을 채취하고, 간 조직검사를 시행하여 H-E stain 하였고, Jamall 등이 기술한 방법에 의하여 간 조직을 가수 분해하여 분비되는 4-hydroxyproline의 양을 구하였다. 결과: 간 조직 검사상 대조군과 비교 하여 사염화탄소를 준 군에서 섬유화가 진행되고 간경변증으로 진행되는 소견을 보였다. 실험군에서 Thallium-201 per rectal scintigraphy에 의한 H/L ratio는 실험군에서 더 증가되는 소견을 보였고, propranolol을 정맥내 투여한 후 0.5, 1, 2, 4시간에서 혈중 농도도 대조군에 비해 모든 실험군에서 통계학 적으로 유의하게(p<0.05) 증가하였다. 배설반감기 (t1/2(β))는 대조군과 실험군들 사이에 통계학적으로 유의한 차이가 없었으나 사염화탄소 투여 군에서 초기 혈중 농도(Co)와 농도곡선하면적(AUC)은 유의하게(p<0.05) 증가하였고, 혈중 청소율(CLp)은 유의하게(p<0.05) 감소하였다. 간 조직의 4-hydroxyproline 양도 실험군에서 유의하게(p<0.05) 증가하였다. H/L ratio, 4-hydroxyproline 양, AUC와 상관성은 있었으나 통계적 유의성은 없었다. 결론: 이런 동물 실험이 약물개발에 있어 임상 시험중 만성 간질환자의 제1c상 시험의 전임상 동물 연구에 도움을 줄 수 있을 것이며, 특히 Thallium-201 per rectal scintigraphy 비침습적인 방법으로 특히 혈류 제한적인 약물의 연구시 약물의 용량 조절에 도움을 줄 것이다. Background: This study was designed to determine the relationship of propranolol pharmacokinetic parameters with portosystemic shunt in CCl4-induced cirrhotic rats. Methods: Cirrhotic rats(n=6) were induced by intramuscular injection of CCl4 in olive oil(two time per weeks) for 12 weeks. Controls (n=6) were injected intramuscularly with the same dose of olive oil for 12 weeks. We evaluated the amount of portosystemic shunt by thallium-201 per rectal scintigraphy. After intravenous bolus injection of propranolol (2mg/kg) to rats, the serum propranolol concentrations were analyzed by a HPLC-fluorimetric detector system. Pharmacokinetic parameters such as C0, AUC, t1/2(β), and CLp were determined in each group. Then, a small amount of heptic tissue was obtained and subjected to determination of the hepatic collagen content by quantitating 4-hydroxyproline and were inspected by microscope after hematoxylin and eosin stain. Results: In liver biopsy, liver fibrosis progressed in CCl4-induced cirrhotic rats. The serum concentrations of propranolol were significantly (p<0.01) elevated in CCl4-induced cirrhotic rats. Mean amount of 4-hydroxyproline, mean H/L ratio, and mean AUC in CCl4-induced cirrhotic rats was significantly (p<0.01) higher than that in control rats. There was a relationship between AUC, H/L ratio, and amount of 4-hydroxyproline. Conclusion: H/L ratio may help in the selection of drug dosage (especially blood flow dependent drug) in pre-clinical studies for chronic liver disease during the drug development process. (Korean J Hepatol 2002;8:277-287)

Equivalent Circuit Model of A Semiconductor Nanowire Field-Effect Transistor

Yun Seop Yu,Sung Ho Choi,Nam Ho Kim 한국정보통신학회 2007 2016 INTERNATIONAL CONFERENCE Vol.1 No.1

Environmental Regulation Effects Revisited: Channel Effects on Industrial Economic Performance

( Yun Seop Hwang ),( Xiaoxu Dong ),( Wonwoong Choi ) 한국생산성학회 2016 生産性論集 Vol.30 No.2

This paper theoretically reviews the researches about the effects of environmental regulations on economic performances. According to the previous researches, we propose that environmental regulations affect industrial economic performances through three channels: export, foreign direct investment, and innovative activities. We collected the related data over the period of 1997-2009 from 14 industries in Korea. The emission amounts of the eight kinds of pollutants were used to calculate the pollutant index as the measure of stringency of environmental regulations. We used the simultaneous equations model and the 3SLS method to solve the endogenous problems between the variables. The results indicated that environmental regulations negatively affect industrial economic performances through export channels. Environmental regulations have insignificant effects on inflow FDI. Although environmental regulations motivate companies to increase R&D investments, it does not influence industrial economic performances through R&D investments. In the future, Korean government should implement various policies of environmental regulations, reinforce economic policies and soft policies to enhance efficiency and flexibility.

Does oil price rise necessarily reduce export?: Focused on Korean exports

( Yun Seop Hwang ),( Young Jun Choi ) 한국생산성학회 2012 生産性論集 Vol.26 No.4

This paper analyzes the effects of oil price change on the value of exports of Korea. The general convention is that the effect of oil price raise is leading to reducing the exports. The change in oil price is related to the change of production costs as well as changes in macroeconomic indices, such as price level and interest rate. Those changes in production costs and macroeconomic indices may affect the performance of exports. However, we found that the oil price increase is not necessarily reducing the exports based on Korean industrial exports data. Rather, in our analysis, the rise of oil price lowers the real interest rate and thus the increase in oil price leads to an increase in the value of Korean exports. It is also found that oil price affects the export directly and indirectly through the real interest rate.