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α - 셀룰로오즈의 열분해에 관한 연구 : 산촉매 NaCl 의 영향 Effect of Acid Catalsts NaCl
나상도,황준호,최경선,설수덕,손진언 한국고무학회 1996 엘라스토머 및 콤포지트 Vol.31 No.2
The Thermal decomposition of the α-Cellulose and NaCl was studied using a thermal analysis technique in the steam of nitrogen gas with 30㎖/min at various heating ranges from 4 to 20℃/min. The Derivative and Integral method used to be obtained values of activation energy of decomposition reaction. 1. The values of activation energy evaluated by Derivative and Intergral method were consistent with each other very well. 2. The maximum value of heat of decomposition evalated by DSC method was α-Cellulose/NaCl=90/10. 3. The thermogravimetric trace curve agreed with the theoretical equation.
A Beginner’s Guide to Randomized Evaluations in Development Economics
E Seul Choi,Booyuel Kim 서울대학교 경제연구소 2016 Seoul journal of economics Vol.29 No.4
We present a practical guide to randomized impact evaluation in Development Economics for people who are interested in starting a field experiment for the first time. We provide an overview of the important steps in planning and implementing a randomized evaluation from beginning to end. The steps include issues such as research question development, local partner institution, institutional review board, pre-analysis plan, samplesize calculation, random sampling, randomization, survey implementation, data entry, and data analysis.
Kim, Seul Ki,Han, E-Jung,Kim, Sun Mie,Lee, Jung Ryeol,Jee, Byung Chul,Suh, Chang Suk,Kim, Seok Hyun The Korean Society for Reproductive Medicine 2016 Clinical and Experimental Reproductive Medicine Vol.43 No.4
Objective: Uterine contraction induced by the embryo transfer (ET) process has an adverse effect on embryo implantation. The aim of this study was to determine the effect of oxytocin antagonist supplementation on the day of ET on in vitro fertilization outcomes via a meta-analysis. Methods: We performed a meta-analysis of randomized controlled trials (RCTs). Four online databases (Embase, Medline, PubMed, and Cochrane Library) were searched through May 2015 for RCTs that investigated oxytocin antagonist supplementation on the day of ET. Studies were selected according to predefined inclusion criteria and meta-analyzed using RevMan 5.3. Only RCTs were included in this study. The main outcome measures were the clinical pregnancy rate, the implantation rate, and the miscarriage rate. Results: A total of 123 studies were reviewed and assessed for eligibility. Three RCTs, which included 1,020 patients, met the selection criteria. The implantation rate was significantly better in patients who underwent oxytocin antagonist infusion (19.8%) than in the control group (11.3%) (n = 681; odds ratio [OR], 1.92; 95% confidence interval [CI], 1.25-2.96). No significant difference was found between the two groups in the clinical pregnancy rate (n = 1,020; OR, 1.57; 95% CI, 0.92-2.67) or the miscarriage rate (n = 456; OR, 0.76; 95% CI, 0.44-1.33). Conclusion: The results of this meta-analysis of the currently available literature suggest that the administration of an oxytocin antagonist on the day of ET improves the implantation rate but not the clinical pregnancy rate or miscarriage rate. Additional, large-scale, prospective, randomized studies are necessary to confirm these findings.
Multiple pregnancy after single or multiple embryo transfer performed according to Korean guidelines
Han, E Jung,Kim, Seul Ki,Lee, Jung Ryeol,Jee, Byung Chul,Suh, Chang Suk,Kim, Seok Hyun The Korean Society for Reproductive Medicine 2015 Clinical and Experimental Reproductive Medicine Vol.42 No.4
Objective: To assess compliance with Korean guidelines for embryo transfer, the possible reasons for non-compliance, and multiple pregnancies according to each specific condition in compliant cycles. Methods: A single-institution, retrospective study was conducted of 256 fresh in vitro fertilization cycles during 2012-2014. To assess compliance with Korean guidelines, the maximum recommended number of embryos transferred (according to criteria of age, transfer day, and presence of favorable conditions) was compared with the actual number of embryos transferred. Clinical pregnancy rate (PR) was assessed as the percentage of pregnant women resulting from each set of transfer conditions, including the number of embryos transferred. The multiple pregnancy rate (MPR) was calculated as the percentage of pregnant women with a multifetal pregnancy. Results: The compliance rate with the Korean guidelines was 96.5% (247/256). Non-compliance occurred in nine cycles owing to poor embryo quality, repeated implantation failure, or hostile endometrium. In compliant cycles, the PR was 31.2% (77/247), and the MPR was 27.3% (21/77; 20 twins and one triplet). Higher MPR was noted in two types of transfer conditions: transfer of three cleavage embryos in women aged 35-39 years with favorable conditions (66.7%; primarily from those aged 35-37 years) and transfer of two blastocysts in women aged ${\geq}40$ years with favorable conditions (50%). Conclusion: Under the Korean guidelines, compliance rate was high in our center. Multiple pregnancies occurred primarily in group with favorable conditions. In high-risk groups for multiple pregnancies, reducing number of embryos transferred should be considered than suggested in the guideline.
Infrared Spectroscopy of Imidazole Trimer in Helium Nanodroplets: Free NH Stretch Mode
Lee, Seul-Ki,Lee, Seung-Jun,Ahn, Ah-Reum,Kim, Yu-Sic,Min, Ah-Reum,Choi, Myong-Yong,Miller, Roger E. Korean Chemical Society 2011 Bulletin of the Korean Chemical Society Vol.32 No.3
We report the first vibrational band assignment of imidazole trimer (IMT) solvated in helium nanodroplets. Several congested vibrational bands of imidazole (IM) clusters were obtained in the frequency region of $3513-3515\;cm^{-1}$ and vibrationally resolved due to the extremely low temperature (0.37 K) and very weak solutesolvent interaction environments of helium droplets. The unambiguous free NH band assignment was achieved with an aid of pick-up oven temperature dependence and vibrational transition moment angle (VTMA) experiments as well as density functional theory (DFT) calculations. The band at $3514.3\;cm^{-1}$ is attributed to the free NH stretching mode of linear IMT clusters, easily formed by the dipole-dipole interactions of IM in ultracold helium nanodroplets.
Hassan, Ahmed H.E.,Cho, Min Chang,Kim, Hye In,Yang, Ji Seul,Park, Kyung Tae,Hwang, Ji Young,Jang, Choon-Gon,Park, Ki Duk,Lee, Yong Sup Elsevier 2018 Bioorganic & medicinal chemistry Vol.26 No.18
<P><B>Abstract</B></P> <P>CRA13; a peripheral dual CB<SUB>1</SUB>R/CB<SUB>2</SUB>R agonist with clinically proven analgesic properties, infiltrates into CNS producing adverse effects due to central CB<SUB>1</SUB>R agonism. Such adverse effects might be circumvented by less lipophilic compounds with attenuated CB<SUB>1</SUB>R affinity. Metabolism produces less lipophilic metabolites that might be active metabolites. Some CRA13 oxidative metabolites and their analogues were synthesized as less lipophilic CRA13 analogues. Probing their CB<SUB>1</SUB>R and CB<SUB>2</SUB>R activity revealed the alcohol metabolite <B>8c</B> as a more potent and more effective CB<SUB>2</SUB>R ligand with attenuated CB<SUB>1</SUB>R affinity relative to CRA13. Also, the alcohol analogue <B>8b</B> and methyl ester <B>12a</B> possessed enhanced CB<SUB>2</SUB>R affinity and reduced CB<SUB>1</SUB>R affinity. The CB<SUB>2</SUB>R binding affinity of alcohol analogue <B>8b</B> was similar to CRA13 while that of methyl ester <B>12a</B> was more potent. <I>In silico</I> study provided insights into the possible molecular interactions that might explain the difference in the elicited biological activity of these compounds.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Design rational based on active metabolite approach. </LI> <LI> Alcoholic, carboxylic metabolites of CRA13 and their analogs were synthesized and evaluated. </LI> <LI> Evaluated compounds were more selective towards CB<SUB>2</SUB>R. </LI> <LI> Compound <B>8c</B> was more potent than CRA13 as CB<SUB>2</SUB>R ligand with attenuated CB<SUB>1</SUB>R affinity. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>
Nersisyan, Hayk,Han, Seul Ki,Choi, Jeong Hun,Lee, Young-Jun,Yoo, Bung Uk,Ri, Vladislav E.,Lee, Jong Hyeon Elsevier 2017 JOURNAL OF NUCLEAR MATERIALS Vol.486 No.-
<P><B>Abstract</B></P> <P>In this paper we describe a progressive two-step process that allows zirconium fluoride (ZrF<SUB>4</SUB>) contained in spent baths for etched zirconium alloys to be effectively recycled on a pilot scale and produce a high purity regenerated pickling acid. In the first step, a spent pickling liquor is treated by a BaF<SUB>2</SUB> suspension to produce water insoluble Ba<SUB>2</SUB>ZrF<SUB>8</SUB>. After filtration of Ba<SUB>2</SUB>ZrF<SUB>8</SUB> more than 99.9 wt % purity pickling acid is regenerated. The precipitation mechanism of Ba<SUB>2</SUB>ZrF<SUB>8</SUB> is discussed and the role of BaF<SUB>2</SUB> particles size on the precipitation process is demonstrated. In the second step the as-precipitated Ba<SUB>2</SUB>ZrF<SUB>8</SUB> is mixed with Mg and Cu metal powders and heat-treated at 1200 °C (or above) to produce CuZr alloy ingot. The characteristics of the ingot are discussed in regard to Cu concentration and the heating temperature.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Two-step process for recycling ZrF<SUB>4</SUB> containing pickling acid on a pilot scale is developed. </LI> <LI> Water insoluble Ba<SUB>2</SUB>ZrF<SUB>8</SUB> is precipitated by mixing spent pickling liquor with BaF<SUB>2</SUB>. </LI> <LI> The recycled pickling acid demonstrates more than 99.9 wt % purity. </LI> <LI> The processing of Ba<SUB>2</SUB>ZrF<SUB>8</SUB> with Cu and Mg metals at 1200 °C yielded CuZr alloy. </LI> <LI> The recovery depth of Zr was more than 95 wt%. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>
Hassan, Ahmed H.E.,Choi, Eunwoo,Yoon, Yoon Mi,Lee, Kun Won,Yoo, Sung Yeun,Cho, Min Chang,Yang, Ji Seul,Kim, Hye In,Hong, Joo Young,Shin, Ji-Sun,Chung, Kyung-Sook,Lee, Jeong-Hun,Lee, Kyung-Tae,Lee, Yon Elsevier 2019 European journal of medicinal chemistry Vol.161 No.-
<P><B>Abstract</B></P> <P>Cancer still represents a major global health problem. All currently available anticancer agents have disadvantages like resistance or side effects. Therefore, introduction of novel anticancer agents is needed. Intrigued by the high success rate for natural products-based drug discovery, we designed and synthesized antiproliferative chemical entities as hybrids of two natural products; 3,5,4′-trimethoxystilbene and 5,6,7-trimethoxyflavone. To probe the spectrum of the synthesized compounds, <I>in vitro</I> evaluation was conducted against nine panels representing major cancer diseases. The results revealed the hybrid analogs <B>4f</B>, <B>4h</B>, <B>4k</B> and <B>4q</B> as promising broad-spectrum anticancer lead compounds eliciting high growth inhibition of several cell lines representing multiple cancers diseases. Evaluation of the promising lead compounds against normal human cell lines suggested a selective cytotoxic effect on cancer cells. Mechanistic investigation of the cytotoxic activity of compound <B>4f</B> in human cervical cancer HeLa cells showed that it triggers cell death through induction of apoptosis. As a whole, this study presents the natural products hybrid analogs <B>4f</B>, <B>4h</B>, <B>4k</B> and <B>4q</B> as potential lead compounds for further development of novel anticancer therapeutics.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Design, synthesis and <I>in vitro</I> antiproliferative evaluation of 3,5,4′-trimethoxystilbene-5,6,7-trimethoxyflavone hybrids. </LI> <LI> Compounds <B>4f</B>, <B>4h</B>, <B>4k</B> and <B>4q</B> elicited promising broad spectrum antiproliferative activity. </LI> <LI> Compounds <B>4f</B>, <B>4h</B>, <B>4k</B> and <B>4q</B> were more selective to human cancer cells rather than normal human cells. </LI> <LI> Compound <B>4f</B> triggered cell death via induction of apoptosis in HeLa cells. </LI> <LI> Compounds <B>4f</B>, <B>4h</B>, <B>4k</B> and <B>4q</B> might be potential leads for development of natural-products based anticancer agents. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>