• Title/Summary/Keyword: Molecular Structure

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Hologram Quantitative Structure Activity Relationship (HQSAR) Study of Mutagen X

  • Cho, Seung-Joo
    • Bulletin of the Korean Chemical Society
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    • v.26 no.1
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    • pp.85-90
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    • 2005
  • MX and its analogs are synthesized and modeled by quantitative structure activity relationship (QSAR) study including comparative molecular field analysis (CoMFA). As a result, factors affecting this class of compounds have been found to be steric and electrostatic effects. Because hologram quantitative structure activity relationship (HQSAR) technique is based on the 2-dimensional descriptors, this is free of ambiguity of conformational selection and molecular alignment. In this study we tried to include all the data available from the literature, and modeled with the HQSAR technique. Among the parameters affecting fragmentation, connectivity was the most important one for the whole compounds, giving good statistics. Considering additional parameters such as bond specification only slightly improved the model. Therefore connectivity has been found to be the most appropriate to explain the mutagenicity for this class of compounds.

Mining Structure Elements from RNA Structure Data, and Visualizing Structure Elements

  • Lim, Dae-Ho;Han, Kyung-Sook
    • Proceedings of the Korean Society for Bioinformatics Conference
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    • 2003.10a
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    • pp.268-274
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    • 2003
  • Most currently known molecular structures were determined by X-ray crystallography or Nuclear Magnetic Resonance (NMR). These methods generate a large amount of structure data, even far small molecules, and consist mainly of three-dimensional atomic coordinates. These are useful for analyzing molecular structure, but structure elements at higher level are also needed for a complete understanding of structure, and especially for structure prediction. Computational approaches exist for identifying secondary structural elements in proteins from atomic coordinates. However, similar methods have not been developed for RNA due in part to the very small amount of structure data so far available, and extracting the structural elements of RNA requires substantial manual work. Since the number of three-dimensional RNA structures is increasing, a more systematic and automated method is needed. We have developed a set of algorithms for recognizing secondary and tertiary structural elements in RNA molecules and in the protein-RNA structures in protein data banks (PDB). The present work represents the first attempt at extracting RNA structure elements from atomic coordinates in structure databases. The regularities in the structure elements revealed by the algorithms should provide useful information for predicting the structure of RNA molecules bound to proteins.

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Fully Rod-like Aromatic Polyimides: Structure, Properties, and Chemical Modifications

  • Moonhor Ree;Shin, Tae-Joo;Lee, Seung-Woo
    • Macromolecular Research
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    • v.9 no.1
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    • pp.1-19
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    • 2001
  • Poly(p-phenylene pyromellitimide) and poly(4,4'-biphenylene pyromellitimide) are representatives of fully rod-like polyimides. Their structure and properties in thin films are reviewed. The polymers exhibit some excellent properties such as high molecular packing coefficient, high mechanical modulus, and low thermal expansion coefficient, and low interfacial stress, so that they are very attractive to both industry and academia. However, these polymers are very brittle and thus practically useless. Some chemical modifications to improve such drawback with a little sacrifice of the high modulus are described: i) incorporation of short side groups into the polymer backbone and ii) insertion of proper linkages into the polymer backbone.

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Analysis of Hematoporphyrin Derivative by Design and Manufacture of High Resolution Charge Coupled Device in Spectrometry (분광기에 고 분해능 Charge Coupled Device의 설계 및 제작에 의한 Hematoporphyrin Derivative의 분석)

  • Kim, Ki-Jun
    • Journal of the Korean Applied Science and Technology
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    • v.22 no.1
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    • pp.77-83
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    • 2005
  • The influence of fluorescence, scattering, and absorbance in turbid material by light scattering was interpreted by the scattered fluorescence intensity and wavelength. The effect of optical property in scattering media was investigated. It is very important to study the charge coupled device(CCD) in spectrometry because we can use the molecular energy level, molecular structure, absorption or emission, intermolecular reaction, weakly bound molecular energy, photochemistry, fluorescence and photodynamic therapy. CCD is very essential to study the molecular structure and medical engineering combined laser spectroscopy in the modem physical and chemistry. Accordingly, this study has designed and manufactured the electromagnetic spectrometry with CCD, and has analyzed the hematoporphyrin derivative.