Proceedings of the Japan Academy, Series B
Online ISSN : 1349-2896
Print ISSN : 0386-2208
ISSN-L : 0386-2208
71 巻, 8 号
選択された号の論文の6件中1~6を表示しています
  • Tamaki NAKANO, Yoshifumi SHIKISAI, Yoshio OKAMOTO
    1995 年 71 巻 8 号 p. 251-255
    発行日: 1995年
    公開日: 2006/10/13
    ジャーナル フリー
    Free radical polymerization of 1-phenyldibenzosuberyl methacrylate was carried out in toluene at 40 or 50°C under chiral reaction conditions based on the use of (-)-dimenthyl peroxydicarbonate as an initiator, (-)- and (+)-menthol as a reaction solvent (additive), and (+)- and (-)-neomenthanethiol as a chain transfer agent. The obtained polymers had a highly isotactic and helical structure; there was an excess of right- or left-handed helicity by the influence of the above chiral materials and consequently, the polymers were optically active. The mechanism of chiral induction for the polymerization using the chiral initiator involved helix-sense-selective primary radical termination, i.e., the reaction between a polymer radical and an initiator radical. In the polymerization using menthol and neomenthanethiol, hydrogen transfer from these chiral compounds to the growing radical appeared to take place in a helix-sense-selective manner.
  • Yasuhide MINONISHI
    1995 年 71 巻 8 号 p. 256-259
    発行日: 1995年
    公開日: 2006/10/13
    ジャーナル フリー
    Transmission electron microscope study has been performed on the pyramidal slip dislocations activated in single crystals of Ti3Al compressed along the c-axis at 600-700°C. The pyramidal slip dislocations are observed to bow out in a form of hairpin. These dislocations are shown to be superpartial dislocations with Burgers vector 1/6<1126>. It is also shown that pairs of unlike superpartials coupled by antiphase boundaries are formed in the same temperature range.
  • Yasuhide MINONISHI
    1995 年 71 巻 8 号 p. 260-264
    発行日: 1995年
    公開日: 2006/10/13
    ジャーナル フリー
    The <1126>{1121} pyramidal slip in Ti3Al shows the so-called yield stress anomaly. Near the peak-stress temperature, specimens collapse by shearing on {1121} slip plane almost immediately after yielding. Transmission electron microscope study revealed that pairs of unlike 1/6<1126>{1121} superpartial dislocations coupled by antiphase boundaries were generated in the same temperature range. These superpartials are of edge in character and are shown further to climb-dissociate on the basal plane into partials of smaller Burgers vector bounding a complex stacking fault: the dissociation is described by an equation 1/6<1126>→1/6<1013>+1/6<0113>. Fracture of single crystals at high temperatures is associated with locking of 1/6<1126> superpartials by climb dissociation.
  • Abdul-Hameed KHADHAIR, Fouad MOMANI, Chuji HIRUKI
    1995 年 71 巻 8 号 p. 265-268
    発行日: 1995年
    公開日: 2006/10/13
    ジャーナル フリー
    This paper describes a simple, rapid and economical method to preserve healthy plant tissues or those infected with phytoplasma for molecular diagnosis and analysis. After thermal treatments, clover proliferation (CP) phytoplasma DNA in periwinkle leaf samples, which was exposed to the microwave heat up to 480sec, remained intact but not after 600sec. The extracted DNA of the CP-infected tissues was amplified with phytoplasma universal primers showing a typical single band of 558bp in the microwave treated samples except the 600sec treatment, or healthy controls. Restriction digestions of PCR products of the heat treated samples with Alu I enzyme showed patterns similar to that with the digested PCR product of a fresh CP-infected sample on 5% polyacrylamide gel-electrophoresis, indicating its stability after the microwave heat treatment. The identity of CP phytoplasma in each heat-treated sample was confirmed by its amplification with specific primers forming a prominent band of 196bp which matched the size of the primer pair that was specific to CP phytoplasma.
  • Hiroshi UEMURA, Masashi SUZUKI
    1995 年 71 巻 8 号 p. 269-273
    発行日: 1995年
    公開日: 2006/10/13
    ジャーナル フリー
    Some structural features of the yeast Gcr1 protein (Gcr1p) are analysed. The protein has three hydrophobic domains separated by hydrophilic residues (referred to as N, L, C), which correspond well with three regions of different functions. The N domain (aal-aa350) corresponds to the region (aa1-aa391) which is important for Gcr1p-Gcr1p and Gcr1p-Gcr2p interactions, while the C domain (aa570-aa785) corresponds to the region (aa631-aa785) which is important for DNA-binding. The function of the L domain (aa360-aa550) remains unknown but it contains many Ser(Thr)-Pro sequences which are potential phosphorylation sites and thus might be used for regulation of the protein function. The sequence, aa631-aa685, resembles those of multi-helical DNA-binding domains found in some transcription factors. In comparison with the DNA-binding mode of known multi-helical DNA-binding domains, DNA base-amino acid side-chain contacts at the Gcr1 site are discussed.
  • Increase by Nitroglycerin and Decrease by NO Synthase Inhibitors
    Sachin A. GUPTE, Takao OKADA, Rikuo OCHI
    1995 年 71 巻 8 号 p. 274-278
    発行日: 1995年
    公開日: 2006/10/13
    ジャーナル フリー
    Isolated rat hearts were perfused with a O2--generating system consisting of purine plus xanthine oxidase for 15 or 20min. After the O2- pretreatment, washout (performed with normal Krebs solution) produced significant elevation of coronary perfusion pressure (CPP). After 20min O2- pretreatment, administration of 4μM nitroglycerin or 1μM sodium nitroprusside, which are nitric oxide (NO) donors, enhanced the elevation of CPP. Conversely, 100μM nitro-L-arginine or 10μM NG-monomethyl-L-arginine, which are NO synthase inhibitors, immediately induced vasorelaxation in O2--pretreated hearts. Thus, it was suggested that NO, a physiological vasodilator, paradoxically augments constriction of the coronary arteries, in O2--pretreated rat heart.
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