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입상 활성탄 표면 개질을 통한 과불화옥탄산 (PFOA) 제거 향상 및 특성 평가
신정우,안병렬 대한상하수도학회 2023 상하수도학회지 Vol.37 No.4
Perfluorooctanoic acid(PFOA) was one of widely used per- and poly substances(PFAS) in the industrial field and its concentration in the surface and groundwater was found with relatively high concentration compared to other PFAS. Since various processes have been introduced to remove the PFOA, adsorption using GAC is well known as a useful and effective process in water and wastewater treatment. Surface modification for GAC was carried out using Cu and Fe to enhance the adsorption capacity and four different adsorbents, such as GAC-Cu, GAC-Fe, GAC-Cu(OH)2, GAC-Fe(OH)3 were prepared and compared with GAC. According to SEM-EDS, the increase of Cu or Fe was confirmed after surface modification and higher weight was observed for Cu and Fe hydroxide(GAC-Cu(OH)2 and GAC-Fe(OH)3, respectively). BET analysis showed that the surface modification reduced specific surface area and total pore volumes. The highest removal efficiency(71.4%) was obtained in GAC-Cu which is improved by 17.9% whereas the use of Fe showed lower removal efficiency compared to GAC. PFOA removal was decreased with increase of solution pH indicating electrostatic interaction governs at low pH and its effect was decreased when the point of zero charges(pzc) was negatively increased with an increase of pH. The enhanced removal of PFOA was clearly observed in solution pH 7, confirming the Cu in the surface of GAC plays a role on the PFOA adsorption. The maximum uptake was calculated as 257 and 345 μg/g for GAC and GAC-Cu using Langmuir isotherm. 40% and 80% of removal were accomplished within 1 h and 48 h. According to R2, only the linear pseudo-second-order(pso) kinetic model showed 0.98 whereas the others obtained less than 0.870.
균열이 있는 기능경사 압전 세라믹의 충격 특성에 관한 연구
신정우,김태욱,김성찬 한국복합재료학회 2003 Composites research Vol.16 No.5
Using the theory of linear piezoelectricity, the dynamic response of a central crack in a functionally graded piezoelectric ceramic under anti-plane shear impact is analyzed. We assume that the properties of the functionally graded piezoelectric material vary continuously along the thickness. By using the Laplace and Fourier transform, the problem is reduced to two pairs of dual integral equations and then into Fredholm integral equations of the second kind. Numerical values on the dynamic stress intensity factors are presented to show the dependence of the gradient of material properties and electric loading. 선형 압전 이론(theory of linear piezoelectricity)을 이용하여 면외전단 충격(anti-plane shear impact)을 받는 기능경사 압전 세라믹(functionally graded piezoelectric ceramic)의 중앙에 존재하는 균열(central crack)의 동적 응답에 대해 연구한다. 기능경사 압전재료의 물성치(material property)는 두께방향을 따라 연속적으로 변한다고 가정한다. 라플라스 변환(Laplace transform)과 푸리에 변환(Fourier transform)을 사용하여 두 쌍의 복합적분 방정식을 구성하며, 이를 제2종 Fredholm 적분 방정식(Fredholm integral equations of the second kind)으로 표현한다. 재료 물성치의 변화도(gradient of material properties)와 전기하중(electric loading)의 영향을 보기 위해 동응력세기계수(dynamic stress intensity factor)에 대한 수치 결과를 제시하였다.
타목시펜이 간세포암 세포주의 성장과 Transforming Growth Factor-β 1의 발현에 미치는 영향
신정우,정영화,박무인,김정아,최민희,이윤정,류수형,박능화,이한주,이영상,서동진,유은실 대한간학회 2003 Clinical and Molecular Hepatology(대한간학회지) Vol.9 No.1
목적: 타목시펜을 진행성 간세포암 환자에게 투여한 결과 일부에서 효과가 있었다는 보고가 있으나 타목시펜이 간세포암의 성장을 억제하는 기전은 밝혀져 있지 않다. TGF-β1은 간세포암의 성장과 분화에 관여하는 중요한 성장인자로 알려져 있으며 최근 타목시펜이 TGF-β1의 분비조절에도 관여한다는 보고들이 있었다. 따라서 본 연구에서는 타목시펜이 간세포암의 성장과 TGF-β1의 발현에 미치는 영향을 알아보고 궁극적으로 타목시펜이 간세포암 환자에게 항암제로 사용될 수 있는지를 알아보고자 하였다. 대상과 방법: 인간 간세포암 세포주인 Hep 3B세포를 에스트로겐이 없는 RPMI 1640과 dextran coated charcoal로 처리한 5% fetal bovine serum을 혼합한 배지에서 3일 배양 후 2×10^4 세포/well로 분주하여 2일간 배양한 후 0.1 μM, 0.5 μM, 1 μM, 5 μM, 10 μM 농도의 타목시펜으로 처치하고 6일간 배양하였다. 매일 세포를 수집하여 trypan blue로 염색한 후 생존 세포수를 산출하였으며 상층액내 TGF-β1 농도는 ELISA법으로 측정하였다. 결과: 비교적 저 농도인 0.1 μM 타목시펜 처치군은 배양 6일째 생존 세포수가 대조군에 비해 의미 있게 증가하였다(2.59×10^6 vs 1.97×10^6, p<0.05). 생존 세포수는 타목시펜농도가 증가할수록 감소하여 10 μM 처치군은 대조군에 비해 의미있는 감소를 보였다(1.4×10^6 vs 1.97×10^6., p<0.05). 상층액내의 TGF-β1dml 분비량은 타목시펜 처치 농도와 상관없이 전 군에서 대조군에 비해 의미있게 감소하였으며 타목시펜 농도에 따른 각 군간에 차이는 없었다. 결론: 타목시펜은 실험실내에서 처치 농도에 따라 간세포암 세포주의 성장에 미치는 영향이 다양했으나, 처치 농도와 관계없이 일정한 정도로 TGF-β1의 발현을 억제하였다. 타목시펜의 이러한 효과는 생체에서 TGF-β1이 과발현된 간세포암의 성장과 진행을 억제할 것으로 생각된다. 또한 타목시펜은 TGF-β1의 발현을 조절하는 기전 이외의 다른 기전을 통해서는 간세포암의 성장을 억제하는 것으로 사료된다. Background/Aims: Tamoxifen has been tried in patients with hepatocellular carcinoma (HCC), however, its inhibitory mechanism remains unknown. In this study, we evaluated the effects of tamoxifen on HCC cell growth and the expression of transforming growth factor-β1 (TGF-β1) which had been known as an important cytokine in growth of HCC. Methods: Hep 3B cells were cultivated in estrogen free media with 0.1 μM, 0.5 μM, 1 μM, 5 μM, and 10μM of tamoxifen for 6 days. Viable cells were counted daily and the TGF-β1 concentrations in supernatant were measured by ELISA method. Results: The number of viable HCC cells increased rather significantly after the treatment of tamoxifen of lower concentration (0.1 μM) compared with that of the control (2.57×10^7 us. 1.97×10^7; p<0.05). As the concentration of treated tamoxifen was higher, the number of viable HCC cells became gradually less, resulting in the significant decrease of it at the highest concentration (10 μM) compared with that of the control (1.40×10^7 us. 1.97×10^7; p<0.05). TGF-β1 concentration in supernatant of tamoxifen-treated samples was significantly decreased compared with those of controls, regardless of the amount of treated tamoxifen. Conclusions: These results suggest that tamoxifen may suppress TGF-β1 expression to an extent, although it has different effects on the proliferation of HCC cells, at the various concentrations of this agent in vitro. Such effects of tamoxifen on TGF-β expression may inhibit the growth and progression of HCCs over-expressing TGF-β1 in vivo.
학회별세션 1/ 후원기관별 세션 : 아시아 태평양 지역의 사회와 보건 (OECD 대한민국 정책센터) ; 한눈에 보는 보건: OECD에서 보는 한국의 보건의료
신정우 한국사회보장학회 2015 한국사회보장학회 정기학술대회 Vol.2015 No.2
This study aims to explain the change of pension characteristics in the perspectives of historical institutionalism in Romania. For these research questions, according to the three periods of pre-socialist, socialist, post-socialist, this study analyzed the economy development, democracy, labor union and international organization related with pension system. The main method of this study was case study based on in-depth interview with local experts. On based this historical context, this study explained whether the path-dependency hypothesis apply to Bismarckian tradition and socialist legacy of pension in Romania.