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Effects of an Endocrine Disruptor (Bisphenol A) on the Mouse Spermatogenesis
남현식,서동삼,고용 한국발생생물학회 2000 발생과 생식 Vol.4 No.1
내분비계 장애물질은 생체내에서 호르몬 등의 내분비계에 영향을 주기 때문에 미량으로도 생식기능에 이상을 가져 올 수 있고, 급·만성 독성과는 달리 차세대에 그 영향이 발현될 수 있다. 대부분의 내분비계 장애물질은 에스트로겐 유사물질로 알려져 있으며, 내분비계 장애물질의 하나인 bisphenol A (BPA)도 이러한 성질을 가진 물질이다. 본 연구는 BPA가 생쥐의 정자형성과정에 어떤 영향을 미치는가를 분석하고자, 농도별 (저농도, 20 mg/kg, 고농 Endocrine disruptors (EDs) are exogenous chemicals which interfere several aspects of natural hormone properties. EDs with estrogenic activity have been recently reported to cause animal reproductive problems. This study was performed to investigate the effects of bisphenol A (BPA) on the mouse spermatogenesis in vivo. Male ICR mice were orally injected on a daily basis with low dose of BPA 20 mg/kg, high dose of BPA 200 mg/kg, or corn oil (vehicle control) for 7 days, and litter size and weights of body, testis, and cauda epididymis were measured. The level of serum testosterone and the expression of TGF- mRNA were also analyzed using RIA and RT-PCR, respectively. Also, morphological differences of testes after treatments were examined. Sperm concentration and level of serum testosterone showed a decreasing tendency detected as untreated >corn oil >low >high dose BPA treated mice, although there were no significant statistical differences. Interestingly, in mice treated with a high dose of BPA, partial disappearance of spermatozoa in seminiferous tubular lumen and the expression of TGF- mRNA were observed. Spermatogenesis was disrupted through TGF- system in the seminiferous tubules, resulting in no development of germ cells. Similarly, the litter size treated with a high dose of BPA was significantly different from that of untreated control group. In conclusion, these results that a high dose of BPA (200 mg/kg) acts as an endocrine disruptor during apermatogenesis in male mice md that there are BPA-specific lesions in the adult male reproductive tract might represent a permanently altered responsiveness to testosterone by BPA in the affected target tissue.
램버시안 구름 모델의 운정기압 오차가 OMI 오존 프로파일 산출에 미치는 영향
남현식 ( Hyeonshik Nam ),김재환 ( Jae Hawn Kim ),신대근 ( Daegeun Shin ),백강현 ( Kanghyun Baek ) 대한원격탐사학회 2019 大韓遠隔探査學會誌 Vol.35 No.3
Lambertian cloud model (Lambertian Cloud Model) is the simplified cloud model which is used to effectively retrieve the vertical ozone distribution of the atmosphere where the clouds exist. By using the Lambertian cloud model, the optical characteristics of clouds required for radiative transfer simulation are parametrized by Optical Centroid Cloud Pressure (OCCP) and Effective Cloud Fraction (ECF), and the accuracy of each parameter greatly affects the radiation simulation accuracy. However, it is very difficult to generalize the vertical ozone error due to the OCCP error because it varies depending on the radiation environment and algorithm setting. In addition, it is also difficult to analyze the effect of OCCP error because it is mixed with other errors that occur in the vertical ozone calculation process. This study analyzed the ozone retrieval error due to OCCP error using two methods. First, we simulated the impact of OCCP error on ozone retrieval based on Optimal Estimation. Using LIDORT radiation model, the radiation error due to the OCCP error is calculated. In order to convert the radiation error to the ozone calculation error, the radiation error is assigned to the conversion equation of the optimal estimation method. The results show that when the OCCP error occurs by 100 hPa, the total ozone is overestimated by 2.7%. Second, a case analysis is carried out to find the ozone retrieval error due to OCCP error. For the case analysis, the ozone retrieval error is simulated assuming OCCP error and compared with the ozone error in the case of PROFOZ 2005-2006, an OMI ozone profile product. In order to define the ozone error in the case, we assumed an ideal assumption. Considering albedo, and the horizontal change of ozone for satisfying the assumption, the 49 cases are selected. As a result, 27 out of 49 cases (about 55%) showed a correlation of 0.5 or more. This result show that the error of OCCP has a significant influence on the accuracy of ozone profile calculation.
비구조형 삼각형 격자에 대한 SMAC기법을 이용한 비압축성 나비어-스톡스 방정식 해법 개발
남현식(Hyeun S. Nam),문영준(Young J. Moon) 한국전산유체공학회 1997 한국전산유체공학회 학술대회논문집 Vol.1997 No.-
An unstructured finite volume method is presented for seeking steady and unsteady flow solutions of the two-dimensional incompressible viscous flows. In the present method, SMAC-type algorithm is implemented on unstructured triangular meshes, using second order upwind scheme for the convective fluxes. Validation tests are made for various steady and unsteady incompressible flows. Convergence characteristics are examined and accuracy<br/> comparisons are made with some benchmark solutions.