알코올성 췌장염 환자에서 CYP2E1 유전자형의 다형성

김일환,염윤기,채석,권준택,김형기,박상흠 순천향의학연구소 2001 Journal of Soonchunhyang Medical Science Vol.7 No.2

Cytochrome P4502E1(CYP2E1) is inducible by ethyl alcohol and activates procarcinogenic N-nitrosodimethylamine(NDMA), benzene, urethane and other lower molecular weight compound. CYP2E1 is also involved in metabolism of certain drugs, for example, alcohol, acetaminophen, tamoxifen, theophylline, flouorinated anesthetics, and chlorozoxazone. CYP2E1 activity was shown to be polymorphically distributed in humans and has been suggested to play a role in hepatocellular carcinoma and alcoholic related disorders. Although genetic predispodition to alcoholism and alcoholic liver disease has been reported, genetic susceptibility to alcoholic pancreatitis is still a matter of debate. The aims of this study were to investigate the allelic frequency of CYP2E1 Rsa I polymorphism in Koreans with alcoholic pancreatitis patients. We investigated the frequency distribution of CYP2E1 Rsa I polymorphism in 212 unrelated healthy Koreans and 64 alcoholic pancreatitis patients. Detection of the CYP2E1 alleles was performed by polymerase chain reaction and restriction fragment length analysis. The genomic DNA was isolated from peripheral blood with conventional phenol: chloroforn extraction method. The allelic frequencies of c1 and c2 in healty volunteers were 0.85 and 0.15, respectively. The allelic frequencies of c1 and c2 in alcoholic pancreatitis patients were 0.8 and 0.2, respectively. The rare type (c2/c2) of CYP2E1 Rsa I polymorphism was 0.005 and 0.031 (p<0.001) in healthy volunteers and alcoholic pancreatitis patients, respectively. However, the CYP2E1 genotype showed no significant relation to the alcoholic pancreatitis patients. It was suggested that the risk of alcoholic pancreatitis diagnosed clinically seem to be not associated with the CYP2E1 genotype.

만성 B형 간염환자에서 인터페론 치료 후 간 조직검사 소견의 변화와 Tumor Necrosis Factor의 임상적 의의

김홍수,윤동진,김은주,정일권,박상흠,이문호,김선주 순천향의학연구소 2000 Journal of Soonchunhyang Medical Science Vol.6 No.2

Background: Interferon has been widely used in the treatment of chronic hepatitis B, but its effectiveness is debatable. The clinical indices as the loss of HBeAg, HBV DNA, and improvement of liver function are applicated to identify the effectiveness of interferon therapy, but the mechanism of hepatohistological change is not well known. We investigated the changes of histologic finding and plasma tumor necrosis factor(TNF) in the patients with chronic hepatitis B after treatment with interferon-alpha. Methods: 11 patients with chronic hepatitis B who had treated by interferon-alpha were enrolled for this study. Liver biopsy was done before and after treatment of interferon and plasma TNF was evaluated at the same time. A semiquantitative study using a histologic scoring system was applied on pre and post liver biopsy specimens and the changes of HBeAg and HBV DNA were also evaluated. Results: Among subjects, the response group, recurrence group, and non-response group based on serologic response with clearance of HbeAg were6, 3, and 2 patients, respectively. The changes of serum ALT level and HBV DNA titer on pre and post therapy decreased significantly in the response group. The change of mean plasma TNF level in the response group decreased insignificantly to 19.4 from 19.9. The histological improvements of grading and staging were shown 4 patients in the response group. Conclusions: Serologic response with clearance of HBeAg was associated with histolofical improvement. The loss of HBsAg in the serum was significant indicator of reduction in the amount of HBV core antigen and HBV surface antigen in the hepatocytes. Plasma TNF level was not associated with response of interferon-alpha therapy and histologic activity.

Analysis of Empirical Constant of Eddy Viscosity by k-ε and RNG k-ε Turbulence Model in Wake Simulation

Park, Il Heum,Cho, Young Jun,Lee, Jong Sup The Korean Society of Marine Environment and safet 2019 海洋環境安全學會誌 Vol.25 No.3

The wakes behind a square cylinder were simulated using two-equation turbulence models, $k-{\varepsilon}$ and RNG $k-{\varepsilon}$ models. For comparisons between the model predictions and analytical solutions, we employed three skill assessments:, the correlation coefficient for the similarity of the wake shape, the error of maximum velocity difference (EMVD) of the accuracy of wake velocity, and the ratio of drag coefficient (RDC) for the flow patterns as in the authors' previous study. On the basis of the calculated results, we discussed the feasibility of each model for wake simulation and suggested a suitable value for an eddy viscosity related constant in each turbulence model. The $k-{\varepsilon}$ model underestimated the drag coefficient by over 40 %, and its performance was worse than that in the previous study with one-equation and mixing length models, resulting from the empirical constants in the ${\varepsilon}-equation$. In the RNG $k-{\varepsilon}$ model experiments, when an eddy viscosity related constant was six times higher than the suggested value, the model results were yielded good predictions compared with the analytical solutions. Then, the values of EMVD and RDC were 3.8 % and 3.2 %, respectively. The results of the turbulence model simulations indicated that the RNG $k-{\varepsilon}$ model results successfully represented wakes behind the square cylinder, and the mean error for all skill assessments was less than 4 %.

Analysis of Empirical Constant of Eddy Viscosity by Zero- and One- Equation Turbulence Model in Wake Simulation

Il Heum Park,Young Jun Cho,Tae Yun Kim,Moon Ock Lee,Sung Su Hwang 해양환경안전학회 2014 海洋環境安全學會誌 Vol.20 No.3

In this paper, the wakes behind a square cylinder were simulated using two kinds of different turbulence models for the eddy viscosity concept such as the zero- and the one-equation model in which the former is the mixing length model and the latter is the k-equation model. For comparison between numerical and analytical solutions, we employed three skill assessments: the correlation coefficient(r) for the similarity of the wake shape, the error of maximum velocity difference(EMVD) for the accuracy of wake velocity and the ratio of drag coefficient(RDC) for the pressure distribution around the structure. On the basis of the numerical results, the feasibility of each model for wake simulation was discussed and a suitable value for the empirical constant was suggested in these turbulence models. The zero-equation model, known as the simplest turbulence model, overestimated the EMVD and its absolute mean error(AME) for r, EMVD and RDC was ranging from 20.3 % to 56.3 % for all test. But the AME by the one-equation model was ranging from 3.4 % to 19.9 %. The predicted values of the one-equation model substantially agreed with the analytical solutions at the empirical mixing length scale L=0.6b1/2 with the AME of 3.4 %. Therefore it was concluded that the one-equation model was suitable for the wake simulation behind a square cylinder when the empirical constant for eddy viscosity would be properly chosen.

Analysis of Empirical Constant of Eddy Viscosity by k-ε and RNG k-ε Turbulence Model in Wake Simulation

Il Heum Park,Young Jun Cho,Jong Sup Lee 해양환경안전학회 2019 海洋環境安全學會誌 Vol.25 No.3

The wakes behind a square cylinder were simulated using two-equation turbulence models, k-ε and RNG k-ε models. For comparisons between the model predictions and analytical solutions, we employed three skill assessments:, the correlation coefficient for the similarity of the wake shape, the error of maximum velocity difference (EMVD) of the accuracy of wake velocity, and the ratio of drag coefficient (RDC) for the flow patterns as in the authors’ previous study. On the basis of the calculated results, we discussed the feasibility of each model for wake simulation and suggested a suitable value for an eddy viscosity related constant in each turbulence model. The k-ε model underestimated the drag coefficient by over 40 %, and its performance was worse than that in the previous study with one-equation and mixing length models, resulting from the empirical constants in the ε-equation. In the RNG k-ε model experiments, when an eddy viscosity related constant was six times higher than the suggested value, the model results were yielded good predictions compared with the analytical solutions. Then, the values of EMVD and RDC were 3.8 % and 3.2 %, respectively. The results of the turbulence model simulations indicated that the RNG k-ε model results successfully represented wakes behind the square cylinder, and the mean error for all skill assessments was less than 4 %.

Analysis of Empirical Constant of Eddy Viscosity by Zero- and One-Equation Turbulence Model in Wake Simulation

Park, Il Heum,Cho, Young Jun,Kim, Tae Yun,Lee, Moon Ock,Hwang, Sung Su The Korean Society of Marine Environment and safet 2014 海洋環境安全學會誌 Vol.20 No.3

In this paper, the wakes behind a square cylinder were simulated using two kinds of different turbulence models for the eddy viscosity concept such as the zero- and the one-equation model in which the former is the mixing length model and the latter is the k-equation model. For comparison between numerical and analytical solutions, we employed three skill assessments: the correlation coefficient(r) for the similarity of the wake shape, the error of maximum velocity difference(EMVD) for the accuracy of wake velocity and the ratio of drag coefficient(RDC) for the pressure distribution around the structure. On the basis of the numerical results, the feasibility of each model for wake simulation was discussed and a suitable value for the empirical constant was suggested in these turbulence models. The zero-equation model, known as the simplest turbulence model, overestimated the EMVD and its absolute mean error(AME) for r, EMVD and RDC was ranging from 20.3 % to 56.3 % for all test. But the AME by the one-equation model was ranging from 3.4 % to 19.9 %. The predicted values of the one-equation model substantially agreed with the analytical solutions at the empirical mixing length scale $L=0.6b_{1/2}$ with the AME of 3.4 %. Therefore it was concluded that the one-equation model was suitable for the wake simulation behind a square cylinder when the empirical constant for eddy viscosity would be properly chosen.

잔교식 항만구조물 주변에서 해수유동의 평가

박일흠(Il Heum Park) 한국해양환경·에너지학회 2004 한국해양환경·에너지학회지 Vol.7 No.2

영일만에서 해면매립에 따른 반사파의 영향

박일흠(Il Heum PARK),이동수(Dong Soo LEE),이문옥(Moon Ock LEE) 전남대학교 수산과학연구소 1999 수산과학연구소논문집 Vol.8 No.-

The effect of reflection wave due to a reclamation in Youngil Bay is discussed. The numerical experiments are performed with the design waves of 50 years frequency. The system of grid nets is composed of large and small fields. The mild slope equation of elliptic type is adopted in the large field and the unsteady mild slope equation of hyperbolic type is also applied to the small field. The energy equation of wave breaking and bottom friction is incorporated with each other to estimate the energy dumping. After reclamation, the maximum change of wave height increases up to the 1.4 times. But the effective boundary of reflection wave is restricted within a small area.

광양만의 섬형태 매립지 주변에서 해수유동과 해수교환

박일흠 ( Il Heum Park ),이문옥 ( Moon Ock Lee ) 한국도서(섬)학회 2008 韓國島嶼硏究 Vol.20 No.1

수조 수치실험에 의한 말뚝구조물의 항력계수 산정

박일흠(Park, Il-Heum),이근효(Lee, Geun-Hyo),조영준(Cho, Young-Jun) 한국해안해양공학회 2009 한국해안해양공학회 논문집 Vol.21 No.1

RNG k?ε 난류모형이 포함된 3차원 동수역학 수치모형(FLOW-3D^R)을 사용하여 수조 수치실험을 통한 항력계수 산정 가능성을 검토하였다. 물리적 실험으로 항력계수가 알려져 있는 말뚝구조물에 대하여, 사각형 말뚝구조물의 수치해에 의한 항력계수값이 1.34~1.52로 물리적 실험값인 1.3~1.5의 범위와 매우 유사한 결과를 보였다. 원형 말뚝구조물은 0.5<h/D<3.5의 범위에서 수조 수치실험치가 0.75~0.78 정도로서 물리적 실험치와 비교적 잘 일치하였다. 그리고 항력계수값이 알려지지 않은 열을 이룬 말뚝구조물의 경우 항력계수값은 구조물 간의 간섭으로 단일 구조물에 비해 항력계수가 크게 나타났으며, 각 구조물간의 거리비가 작아짐에 따라 구조물이 받는 항력계수값은 증가하는 양상을 보였다. A possibility of the drag coefficient estimation in numerical water basins was discussed where the numerical solution were calculated by the 3-dimensional hydro-dynamical model (FLOW-3D^R) with the RNG k?ε turbulence model. On the known cases of the drag coefficients for a rectangle, the numerical drag coefficients got 1.34~1.52 and the wind tunnel values were 1.3~1.5. For a cylinder, the numerical values were calculated as 0.75~0.78 in the range of 0.5<h/D<3.5. Therefore the numerical results showed a good agreement with the physical experiment in a cylinder body runs. On the unknown cases of a row of rectangle, the drag coefficients were more increase than the cases of single body because of the interaction of other structures. And also the drag coefficients had large values as the distance interval ratio of the structures more and more decrease.