Proceedings of the Japan Academy, Series B
Online ISSN : 1349-2896
Print ISSN : 0386-2208
ISSN-L : 0386-2208
Volume 86, Issue 9
Displaying 1-5 of 5 articles from this issue
  • Michinori OKI
    2010 Volume 86 Issue 9 Pages 867-883
    Published: November 11, 2010
    Released on J-STAGE: November 12, 2010
    Isolation of rotational isomer models of ethane-type molecules is described. We could experimentally prove that, if rotational isomers whose molecular shape was chiral, the molecule could be optically active, even though it did not carry an asymmetric carbon atom. As an extension, other types of stereochemically fundamental and optically active molecules were isolated and their absolute stereochemistry was determined. One example is the model of meso-tartaric acid, for which optical inactivity had been attributed to internal compensation but is now explained as follows. On dissolution of meso-tartaric acid in a solvent, the molecule gives two kinds of conformers, one of which is a Ci molecule and the other is a C1 molecule. Although the latter is intrinsically optically active, the optical activity is cancelled by its enantiomer. The theory of internal compensation is recommended to be abandoned. As an extension to another area, some reactions of conformers are also discussed.

    (Communicated by Teruaki MUKAIYAMA, M.J.A.)
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  • Hideo NAKAJIMA
    2010 Volume 86 Issue 9 Pages 884-899
    Published: November 11, 2010
    Released on J-STAGE: November 12, 2010
    Lotus-type porous metals with aligned long cylindrical pores are fabricated by unidirectional solidification from the melt with a dissolved gas such as hydrogen, nitrogen, or oxygen. The gas atoms can be dissolved into the melt via a pressurized gas atmosphere or thermal decomposition of gaseous compounds. Three types of solidification techniques have been developed: mold casting, continuous zone melting, and continuous casting techniques. The last method is superior from the viewpoint of mass production of lotus metals. The observed anisotropic behaviors of the mechanical properties, sound absorption, and thermal conductivity are inherent to the anisotropic porous structure. In particular, the remarkable anisotropy in the mechanical strength is attributed to the stress concentration around the pores aligned perpendicular to the loading direction. Heat sinks are a promising application of lotus metals due to the high cooling performance with a large heat transfer.

    (Communicated by Akihisa INOUE, M.J.A.)
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    2010 Volume 86 Issue 9 Pages 900-913
    Published: November 11, 2010
    Released on J-STAGE: November 12, 2010
    Higher plants utilize various mechanisms to maintain iron homeostasis. To acquire sparingly soluble iron from the rhizosphere, graminaceous plants synthesize natural iron (III) chelators known as mugineic acid family phytosiderophores (MAs). Recent research has uncovered various genes involved in iron uptake and translocation, as well as factors regulating the expression of these genes, especially in rice. Manipulation of these molecular components is used to produce transgenic crops with enhanced tolerance to iron deficiency, or with a high seed iron content. Since iron homeostasis is closely linked to that of other mineral elements, an understanding of this phenomenon will serve as the basis for the production of crops with low concentrations of toxic metals and transgenic plants for phytoremediation.

    (Communicated by Teruhiko BEPPU, M.J.A.)
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Original Papers
  • Yoshiaki ORIHARA, Masashi KAMOGAWA, Akihiro TAKEUCHI, Hiroaki FUKASE, ...
    2010 Volume 86 Issue 9 Pages 914-919
    Published: November 11, 2010
    Released on J-STAGE: November 12, 2010
    Following the electric current injection experiment carried out in 2009, a VLF-MT (Very Low Frequency Magnetotelluric) survey has been conducted in Kozu-shima Island to obtain further information on the subterranean electrical structure that might help understanding the results of our monitoring of geoelectric potentials. A number of VAN-type pre-seismic geoelectric potential anomalies were observed in 1997–2000, even showing a remarkable “Selectivity”. However, similar pre-seismic anomalies were not observed during the Izu-Island volcano-seismic swarm 2000. All these observations would require extremely high degree of heterogeneity in the subterranean electrical structure of the volcanic island and its possible time changes. Several correlations between the results of this survey and the volcanic geology of the island and ground water distribution were found. Further investigation is needed for a complete explanation of the observed phenomena.

    (Communicated by Seiya UYEDA, M.J.A.)
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  • Takaaki AOKI, Minako HIRANO, Yuko TAKEUCHI, Toshihide KOBAYASHI, Toshi ...
    2010 Volume 86 Issue 9 Pages 920-925
    Published: November 11, 2010
    Released on J-STAGE: November 12, 2010
    Single channel currents of lysenin were measured using artificial lipid bilayers formed on a glass micropipette tip. The single channel conductance for KCl, NaCl, CaCl2, and Trimethylammonium-Cl were 474 ± 87, 537 ± 66, 210 ± 14, and 274 ± 10 pS, respectively, while the permeability ratio PNa/PCl was 5.8. By adding poly(deoxy adenine) or poly(L-lysine) to one side of the bilayer, channel currents were influenced when membrane voltages were applied to pass the charged molecules through the channel pores. Current inhibition process was concentration-dependent with applied DNA. As the current fluctuations of α-hemolysin channels is often cited as the detector in a molecular sensor, these results suggest that by monitoring channel current changes, the lysenin channel has possibilities to detect interactions between it and certain biomolecules by its current fluctuations.

    (Communicated by Fumio OOSAWA, M.J.A.)
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