Proceedings of the Japan Academy, Series B
Online ISSN : 1349-2896
Print ISSN : 0386-2208
ISSN-L : 0386-2208
Volume 78, Issue 4
Displaying 1-3 of 3 articles from this issue
  • A superb glycosyl donor in glycosylation
    Teruaki MUKAIYAMA, Hideki JONA
    2002 Volume 78 Issue 4 Pages 73-83
    Published: 2002
    Released on J-STAGE: October 17, 2006
    Catalytic and stereoselective glycosylations using glycosyl fluorides are described: 1) activation of armed glycosyl fluorides by trityl tetrakis(pentafluorophenyl)borate [TrB(C6F5)4] catalyst in trifluoromethylbenzene (BTF)-pivalonitrile ('BuCN)(5:1) to afford the corresponding disaccharides in high yields with good to high β-stereoselectivity; 2) activation of disarmed glycosyl fluorides by the combined use of silver tetrakis(pentafluorophenyl)borate [AgB(C6F5)4] and stannous chloride (SnCl2) or stannic chloride
    (SnCl4); and 3) selective α or β glycosylation using glycosyl fluoride by an appropriate choice of erotic acid catalysts and solvents. Also, the effect of counter anions of erotic acid catalysts on controlling the stereo-selectivities of glycosylation is newly noted. Finally, efficient one-pot sequential syntheses of trisaccharide, F1α antigen, and branched heptasaccharide are demonstrated.
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  • Yoshihide KOZAI
    2002 Volume 78 Issue 4 Pages 84-90
    Published: 2002
    Released on J-STAGE: October 17, 2006
    An analytical expression for the orbit of a dust particle ejected from a comet is derived as the two-body problem by including solar radiation pressure effects. Then deviations of the semi-major axis, the eccentricity and the epoch of the perihelion passage of the particle from those of the comet are expressed as functions of a parameter depending on the ejection velocity, the size of the particle and the true anomaly at the ejection point. Furthermore, numerical values are computed for comet 55P/Tempel-Tuttle which has produced Leonid meteor showers. Finally, perturbations due to Jupiter, Saturn and Uranus are roughly computed and an idea to predict meteor showers is proposed.
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  • Yoshinori IKARASHI, Kazunori KATO, Mitsuzi YOSHIDA, Hiro WAKASUGI
    2002 Volume 78 Issue 4 Pages 91-95
    Published: 2002
    Released on J-STAGE: October 17, 2006
    U1B3.3 monoclonal antibody (mAb) was established by immunizing a rat with the tMK-2U lymphoma cell line, derived from athymic nude mice. U1B3.3 mAb recognizes some T cell populations, B cells and natural killer (NK) cells. U1B3.3+ T cells express CD3/T cell receptor (TCR) complex at a unique intensity: between that of TCR-intermediate cells (TCRint cells) and TCRbright cells. TCRint cells strongly express the interleukin-2 receptor β chain (IL-2Rβ), but almost all U1B3.3+ T cells express high or low levels of IL-2Rβ. When purified U1B3.3+ NK1.1-T cells were cultured with IL-2, approximately 14% of the cells acquired expression of NK1.1 molecules, which are expressed on NK cells and natural killer T (NKT) cells. Furthermore, U1B3.3+ NK1.1-T cells killed tumor cells after culture with IL-2. These results indicate that U1B3.3 mAb recognizes a precursor of NK1.1+ cytotoxic T cells generated by IL-2.
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