• Title/Summary/Keyword: Chemistry education

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Analysis of Students' and Teachers' Questions Posted on Chemistry Q&A Board in a Chemistry Education Homepage (화학교육 홈페이지의 화학 Q&A 게시판에 등록된 학생과 교사 질문 분석)

  • Han, Jae-Young;Ji, Youn-Jung;Lee, Jae-Youn
    • Journal of the Korean Chemical Society
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    • v.56 no.1
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    • pp.137-143
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    • 2012

  • This study analyzed the questions posted on the chemistry Q&A board by students and teachers in a chemistry education homepage, in order to understand the difficulties in learning and teaching chemistry. The different tendencies were found in the contents and the motivations of questions by students and teachers. In Chemistry I, students raised many questions in the 'Water' unit, while teachers raised many ones in the 'Chemical compound in our life' unit. In Chemistry II, students asked many questions in the 'Gas, liquid, solid' unit, while teachers did in 'Chemical reaction and energy' unit. Students' motivations of questioning were 'Explanation of unclear concept', and 'Problem solving', while teachers' motivations were 'Searching information', and 'Question in experiment'. The Q&A board provided a field in exchanging informations needed in learning and teaching chemistry. Educational implications were discussed on the use of Q&A board in chemistry education.

  • https://doi.org/10.5012/jkcs.2012.56.1.137 인용 PDF KSCI KPUBS HTML

Study on Thermodynamics of Three Kinds of Benzindocarbocyanine Dyes in Aqueous Methanol Solution

  • Huang, Wei;Wang, Lan-Ying;Fu, Yi-Le;Liu, Ji-Quan;Tao, You-Ni;Fan, Fang-Li;Zhai, Gao-Hong;Wen, Zhen-Yi
    • Bulletin of the Korean Chemical Society
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    • v.30 no.3
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    • pp.556-560
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    • 2009

  • Aggregation behavior of three kinds of benzindocarbocyanine dyes in aqueous methanol solution was studied by UV-Vis absorption spectrum. The results indicated that the three dyes all existed monomer-dimer equilibrium in aqueous methanol solution (concentration range $10^{−5}\;to\;10^{−6}$ M) at 25.0$\sim$41.0 ${^{\circ}C}$ for Dye 1, 28.0$\sim$49.0 ${^{\circ}C}$ for Dye 2 and 26.0$\sim$47.0 ${^{\circ}C}$ for Dye 3. The fundamental property of the three dyes as the dimeric association constant KD, the dimeric free energy ${\Delta$}G_D, the dimeric entropy ${\Delta$}S_D, and the dimeric enthalpy ${\Delta$}H_D were determined. The ${\Delta$}H_D of three dyes: Dye 1, Dye 2 and Dye 3 was -42.5, -15.1 and -18.9 kJ/mol, respectively. The experimental observations were the subject of a theoretical study including the ground-state geometries which were fully optimized using DFT at B3LYP/6-31G level. The effect of dye molecule structure on ${\Delta$}H_D was discussed by theoretical calculations.

  • https://doi.org/10.5012/bkcs.2009.30.3.556 인용 PDF KSCI

Cytotoxic Isoflavanones from Uraria clarkei

  • Huang, Xiang-Zhong;Bai, Xi-Shan;Liang, Hui;Wang, Chao;Li, Wen-Juan;Guo, Jun-Ming;Jiang, Zhi-Yong
    • Bulletin of the Korean Chemical Society
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    • v.34 no.5
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    • pp.1421-1424
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    • 2013

  • Two new isoflavanones, (3R) 5,7,3',4'-tetrahydroxy-2'-methoxyisoflavanone (1) and (3R) 5',8-di-(${\gamma}$,${\gamma}$-dimethylallyl)-2',5-dihydroxyl-4',7-dimethoxyl-isoflavanone (2), were isolated from Uraria clarkei, together with two known compounds dalbergioidin (3), 5,7-dihydroxy-2',4'-dimethoxyisoflavanone (4). The structures involving the absolute configuration of the new compounds were well elucidated by MS, IR, UV, CD, 1D and 2D NMR analyses. Cytotoxicity of the four compounds were assessed, results suggested that compound 2 possessed well cytotoxic activity, against the Hela, K562, and HL60 cell lines with $IC_{50}$ values of 28.0, 40.6 and $35.1{\mu}M$, respectively.

  • https://doi.org/10.5012/bkcs.2013.34.5.1421 인용 PDF KSCI

Human Intersectin 2 (ITSN2) binds to Eps8 protein and enhances its degradation

  • Ding, Xiaofeng;Yang, Zijian;Zhou, Fangliang;Hu, Xiang;Zhou, Chang;Luo, Chang;He, Zhicheng;Liu, Qian;Li, Hong;Yan, Feng;Wang, Fangmei;Xiang, Shuanglin;Zhang, Jian
    • BMB Reports
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    • v.45 no.3
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    • pp.183-188
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    • 2012

  • Participates in actin remodeling through Rac and receptor endocytosis via Rab5. Here, we used yeast two-hybrid system with Eps8 as bait to screen a human brain cDNA library. ITSN2 was identified as the novel binding factor of Eps8. The interaction between ITSN2 and Eps8 was demonstrated by the in vivo co-immunoprecipitation and colocalization assays and the in vitro GST pull-down assays. Furthermore, we mapped the interaction domains to the region between amino acids 260-306 of Eps8 and the coiled-coil domain of ITSN2. In addition, protein stability assays and immunofluorescence analysis showed ITSN2 overexpression induced the degradation of Eps8 proteins, which was markedly alleviated with the lysosome inhibitor NH4Cl treatment. Taken together, our results suggested ITSN2 interacts with Eps8 and stimulates the degradation of Eps8 proteins.

  • https://doi.org/10.5483/BMBRep.2012.45.3.183 인용 PDF KSCI