KOBUNSHI RONBUNSHU
Online ISSN : 1881-5685
Print ISSN : 0386-2186
ISSN-L : 0386-2186
Volume 67, Issue 4
Displaying 1-4 of 4 articles from this issue
Review Articles
  • Kenji OKUYAMA, Tatsuya KAWAGUCHI
    2010 Volume 67 Issue 4 Pages 229-247
    Published: 2010
    Released on J-STAGE: April 23, 2010
    JOURNAL FREE ACCESS
    The triple helix is a specialized protein motif found in all collagens. The molecular conformation of the collagen-helix confers strict amino acid sequence constraints requiring a Glycine at every third position and a high content of imino acid. Although the X-ray diffraction pattern of fibrous collagen has been studied since the 1920s, deficiencies in the diffraction data have prevented efforts to obtain the unique helical model from the fiber diffraction pattern only. On the other hand, during the past 15 years, many single crystal analyses of collagen model peptides provide various important physicochemical information, including average helical symmetry, the presence of hydrogen bond networks, distribution of water molecules, and structural bases of stabilization of a triple helix induced by hydroxyproline.
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Original Papers
  • Takeru IWAMURA, Masato SAKAGUCHI
    2010 Volume 67 Issue 4 Pages 248-253
    Published: 2010
    Released on J-STAGE: April 23, 2010
    JOURNAL FREE ACCESS
    PVA-TEMPO as a polymer spin reagent was synthesized from poly(vinyl alcohol) (PVA) and 4-(2-chloroacetamido)-2,2,6,6-tetramethylpiperidine 1-oxyl (4-2C-TEMPO). PVA-TEMPO was doped into agarose gel. When the PVA-TEMPO-doped agarose gel was measured by ESR spectroscopy, the molecular motion of PVA-TEMPO found to be slower than the PVA-TEMPO aqueous solution in the temperature range from 7 to 60°C. On the other hand, PEG-TEMPO, which was synthesized from PEG and 4-2C-TEMPO, was doped into agarose gel. When the PEG-TEMPO-doped agarose gel was measured by ESR spectroscopy, no differences in molecular motion of PEG-TEMPO between in the PEG-TEMPO-doped agarose gel and in the PEG-TEMPO aqueous solution were recognized in the temperature range from 7 to 60°C. In this article, we discuss the internal environment of agarose gel from the ESR spectroscopy and the FT-IR spectroscopy results.
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  • Toshihiro HIEJIMA
    2010 Volume 67 Issue 4 Pages 254-262
    Published: 2010
    Released on J-STAGE: April 23, 2010
    JOURNAL FREE ACCESS
    The spacer conformations of two main-chain liquid crystals (LCs), CNφφ-OCH2CH2-X-CH2CH2O-φφCN (X=O; CBE2, X=CH2; CBA5), have been investigated on the basis of conformational energies derived from density functional calculations and the orientational order parameters from 2H NMR experiments under the rotational isomeric state approximation. Polarization microscopic and differential calorimetric observations revealed that CBA5 and CBE2 form an enantiotropic and a monotropic nematic LC phase, respectively. The intramolecular orientational correlation P2(cos ψ) of CBA5 was found to remain invariant over the entire range of the LC phase, whereas P2(cos ψ) of CBE2 definitely decreases with decreasing temperature. Here, ψ stands for the angle between mesogenic core and molecular axis. These results suggest that LC molecules will show the so-called nematic conformation to adapt themselves to the uniaxial potential field, and that the stability of nematic conformation attributed to the bond rotational characteristic of chain segment (CO-C-C-X) strongly correlates with the stability of the nematic LC phase.
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  • Shigeki HIKASA, Kazuya NAGATA, Yoshinobu NAKAMURA
    2010 Volume 67 Issue 4 Pages 263-269
    Published: 2010
    Released on J-STAGE: April 23, 2010
    JOURNAL FREE ACCESS
    The influences of combined elastomers on impact properties and morphology of polypropylene (PP)/elastomer/CaCO3 ternary composites were investigated. When polystyrene-block-poly(ethylene-butene)-block-polystyrene triblock copolymer (SEBS) and poly(ethylene-octene) copolymer (EOR) were used as elastomer, the core-shell elastomer particles with EOR-core and SEBS-shell were formed. The elastomer particles and CaCO3 particles were separately dispersed in PP matrix. When carboxylated SEBS (C-SEBS) combined with EOR were used as elastomer, the C-SEBS particles were dispersed in EOR particles. CaCO3 particles were dispersed in PP matrix, whereas a part of the CaCO3 particles were dispersed in C-SEBS/EOR combined particles. Impact strength increased with the amount of incorporated CaCO3 particles. The effect of elastomer on the impact strength was SEBS ≥ SEBS/EOR > EOR = C-SEBS/EOR > C-SEBS. The morphology formed by elastomer and CaCO3 particles strongly affected the impact properties of the ternary composites.
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