• Title/Summary/Keyword: Crystallography

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Studies of Inter/intramolecular Weak Interactions with CH… S; and S…arene Interaction in Symmetrical and Dissymmetrical Models

  • Dubey, Rashmi;Tewari, Ashish K.;Ravikumar, K.;Sridhar, B.
    • Bulletin of the Korean Chemical Society
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    • v.31 no.5
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    • pp.1326-1330
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    • 2010
  • Evidences have proved the versatile role of sulfur atom in supramolecular chemistry. $^1$Presence of S atom in the molecule usually results in the specific structural properties of molecules. In the present study, $S{\cdots}arene$, $N{\cdots}arene$, $CH{\cdots}{\pi}$, $CH{\cdots}S$ and $CH{\cdots}N$ type of weak interactions stabilize the conformation and self assembly of symmetrical as well as dissymmetrical molecules.

Crystallography Analysis of the β-Mg17Al12 Precipitates by the Secondary Constrained Coincident Site Lattice Model

  • Huang, Xuefei;Huang, Weigang
    • Applied Microscopy
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    • v.45 no.4
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    • pp.230-235
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    • 2015
  • Crystallographic models are effective tools to interpret, calculate and even to predict the preferred crystallographic morphologies of precipitates in various precipitation systems. The present study gives an introduction on the recently developed secondary constrained coincident site lattice (II-CCSL) model. Using the II-CCSL model, the interface matching condition of the ${\beta}-Mg_{17}Al_{12}$ precipitates with ${\alpha}-Mg$ matrix in an aged AZ91 alloy has been analyzed to rationalize the morphologies of the precipitates. The results show that the characteristic crystallographic features of the observed ${\beta}-Mg_{17}Al_{12}$ precipitates, i.e., the habit plane of the ${\beta}-Mg_{17}Al_{12}$ lath with a Burgers orientation relationship (OR) and the growth direction of the ${\beta}-Mg_{17}Al_{12}$ with a Crawley OR exhibit a better lattice matching degree than their vicinal orientations. Moreover, the Crawley OR is preferred to the Burgers OR due to a better lattice match.

Structure-based Functional Discovery of Proteins: Structural Proteomics

  • Jung, Jin-Won;Lee, Weon-Tae
    • BMB Reports
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    • v.37 no.1
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    • pp.28-34
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    • 2004
  • The discovery of biochemical and cellular functions of unannotated gene products begins with a database search of proteins with structure/sequence homologues based on known genes. Very recently, a number of frontier groups in structural biology proposed a new paradigm to predict biological functions of an unknown protein on the basis of its three-dimensional structure on a genomic scale. Structural proteomics (genomics), a research area for structure-based functional discovery, aims to complete the protein-folding universe of all gene products in a cell. It would lead us to a complete understanding of a living organism from protein structure. Two major complementary experimental techniques, X-ray crystallography and NMR spectroscopy, combined with recently developed high throughput methods have played a central role in structural proteomics research; however, an integration of these methodologies together with comparative modeling and electron microscopy would speed up the goal for completing a full dictionary of protein folding space in the near future.

Study on the Orientation of Particles in Tablets (정제내부의 입자배열에 관한 연구)

  • Sohn, Young-Taek
    • Journal of Pharmaceutical Investigation
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    • v.21 no.3
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    • pp.125-132
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    • 1991
  • Using X-ray crystallography powder diffraction, the quantitative representation method of preferred orientation of particles ill tablets was developed. Selected faces of a tablet. the upper surface and faces cut parallel and normal to the upper surface, were presented to an X-ray beam and X-ray diffraction patterns for these faces were measured. The effects of particle size. tableting pressure, and particle form on the preferred orientation were also investigated. It was also recognized that the degree of anisotropy in terms of capping tendency was influenced by the preferred orientation of particles in tablets.

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Effects of Crystal Modification of Cephalothin Sodium on Dissolution and Stability (세파로틴 나트륨의 결정형이 용출과 안정성에 미치는 영향)

  • Sohn, Young-Taek;Park, Sun-Hee
    • YAKHAK HOEJI
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    • v.41 no.3
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    • pp.321-327
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    • 1997
  • Investigation of polymorphism has become a requirement in the pharmaceutical industry because the physical properties and bioavailabilities of crystalline drugs depend on their polymorphic form. Five polymorphic modifications and one pseudopolymorphic modification of ecphalothin sodium were prepared by recrystallization, and characterized by UV spectrophotometer, DSC, TGA and X-ray crystallography. The solubilities of all modifications were examined by the disslution test. Form 2 and 1 showed higher solubilities than any other crystal forms. The modifications were also investigated for their stability after storage of 2 months at 100%, 76%, 52% and 0% humidity.

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Drug Designing for Biologically Important Organic Compound against COX-2 Enzyme: A Computational Approach

  • Sharmila, P.;Malathy, P.;Jagadeesan, G.;Gunasekaran, K.;Aravindhan, S.
    • Journal of Integrative Natural Science
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    • v.8 no.3
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    • pp.204-208
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    • 2015
  • Pyrazole, ${\beta}$-lactam, salicidine, pyren and oxazole derivatives exhibit a broad spectrum of biological activities such as antimicrobial, anti-inflammatory and antitumor activities. With growing application on their synthesis and bioactivity, chemists and biologists in recent years have considerable attention on the research of these derivatives. In the view of potential importance of these derivatives, we have crystallized few of the derivatives and its report has been published. The present study focuses on docking studies of these derivatives against COX-2 enzyme. Docking studies using Schrodinger's GLIDE reveals that these derivatives shows better binding energy and score in the defined active site. These results may provide a guiding role to design a lead molecule which may reduce inflamation.