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定比关系的对称化及其应用
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作者 张忠旺 《数学教学通讯(中教版)》 1999年第5期12-13,共2页
二次曲线的弦问题中,常涉及到定比关系,如何将这一关系转化为便于应用韦达定理的对称形式,是解决这类问题的关键,本文通过实例谈谈这类问题的几种转化方法.设 P_1P_2为二次曲线的弦,P_1、P_2的坐标分别为(x_1,
关键词 定比关系 对称化 二次曲线
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Molecular Modeling and Design of Arylthioindole Derivatives as Tubulin Inhibitors 被引量:1
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作者 Si-yan Liao Ti-fang Miao +2 位作者 Jin-can Chen Hai-liang Lu Kang-cheng Zheng 《Chinese Journal of Chemical Physics》 SCIE CAS CSCD 2009年第5期473-480,I0001,共9页
Three-dimensional quantitative structure activity relationship (3D-QSAR) and docking studies of a series of arylthioindole derivatives as tubulin inhibitors against human breast cancer cell line MCF-7 have been carr... Three-dimensional quantitative structure activity relationship (3D-QSAR) and docking studies of a series of arylthioindole derivatives as tubulin inhibitors against human breast cancer cell line MCF-7 have been carried out. An optimal 3D-QSAR model from the comparative molecular field analysis (CoMFA) for training set with significant statistical quality (R2=0.898) and predictive ability (q2=0.654) was established. The same model was further applied to predict pIC50 values of the compounds in test set, and the resulting predictive correlation coefficient R2(pred) reaches 0.816, further showing that this CoMFA model has high predictive ability. Moreover, the appropriate binding orientations and conformations of these compounds interacting with tubulin are located by docking study, and it is very interesting to find the consistency between the CoMFA field distribution and the 3D topology structure of active site of tubulin. Based on CoMFA along with docking results, some important factors improving the activities of these compounds were discussed in detail and were summarized as follows: the substituents R3-R5 (on the phenyl ring) with higher electronegativity, the substituent R6 with higher eleetropositivity and bigger bulk, the substituent R7 with smaller bulk, and so on. In addition, five new compounds with higher activities have been designed. Such results can offer useful theoretical references for experimental works. 展开更多
关键词 Arylthioindole derivative Tubulin inhibitor Quantitative structure activity relationship Comparative molecular field analysis Docking study
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3D-QSAR and action mechanism of potential dual inhibitors towards AP-1 and NF-κB
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作者 QIAN Li LIAO Si-yan MIAO Ti-fang SHEN Yong ZHENG Kang-cheng 《Journal of Chemistry and Chemical Engineering》 2009年第1期1-12,共12页
Three-dimensional quantitative structure-activity relationship (3D-QSAR) and docking studies of a series of novel dioxopyrrolinyl-amino-pyrimidine derivatives, which are potential dual inhibitors mediating a transcr... Three-dimensional quantitative structure-activity relationship (3D-QSAR) and docking studies of a series of novel dioxopyrrolinyl-amino-pyrimidine derivatives, which are potential dual inhibitors mediating a transcriptional activation towards protein-1 (AP-1) and nuclear factor kappa B (NF-κB), have been carried out. The QS, AR models established by comparative molecular field analysis (CoMFA) and comparative molecular similarity index analysis (CoMSIA) show a good predictive ability with cross-validated coefficients q2 of 0.644 and 0.636, respectively. The docking result shows that there are quite lower average values of the flexible and rigid energy scores on the selected binding sites, meanwhile, it further shows that the binding sites just fall on the joint regions between AP-1 (and NF-κB) and DNA. The reason that these analogues have inhibition function towards AP-I and NF-κB is that their existence on these joint regions can effectively prevent free AP-I and NF-κB from binding to DNA. These results can offer a valuable theoretical reference to the pharmaceutical molecular design as well as the action mechanism analysis. 展开更多
关键词 pyrimidine derivative 3D-QSAR docking analysis activator protein-1 nuclear factor kappa B
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