Proceedings of the Japan Academy, Series B
Online ISSN : 1349-2896
Print ISSN : 0386-2208
ISSN-L : 0386-2208
Volume 74 , Issue 1
Showing 1-4 articles out of 4 articles from the selected issue
  • Nobuhiro MIURA, Shin YAGIHARA, Satoru MASHIMO, Hong GU, Akio TERAMOTO
    1998 Volume 74 Issue 1 Pages 1-5
    Published: 1998
    Released: October 17, 2006
    JOURNALS FREE ACCESS
    Aqueous solutions of schizophyllan are known to undergo a sharp order-disorder structure transition, where the ordered structure is formed of the side chains of the polysaccharide along with nearby water molecules around its helix core. The structured water in the ordered state is positionally fixed butrotates reacting with an electric field of about 100MHz as detected by time-domain reflectometry. The same method was extended to a wide temperature range between -20 and 30°C encompassing the freezing point of about -6°C. A 17.8wt% D2O solution showed both free and structured water dispersions at 0°C, but only the latter one below the freezing point. Thus we concluded that the structured water around the helix core remains unfrozen and mobile even when the system is frozen and no free water exists.
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  • Tohru SHIGA
    1998 Volume 74 Issue 1 Pages 6-11
    Published: 1998
    Released: October 17, 2006
    JOURNALS FREE ACCESS
    Smart polymer gels actively change their size, structure, or viscoelastic properties in response to external signals. The stimuli-responsive properties, indicating a kind of intelligence offer the possibility of new gel-based technology. This paper presents two types of electromechanical behavior that take place in smart polymer gels. One is an anisotropic swelling of polyelectrolyte gels in a salt solution under the influence of electric fields. The swelling deformation produces bending of rectangular gels with large deflection. The swelling or bending is found to be induced by an increase in osmotic pressure due to ion's drifts in electric fields. The other concerns composite gels whose modulus of elasticity can vary in electric fields. The driving force causing varying elastic modulus in electric fields is the interaction between polarized particles similar to electrorheological (ER) effect and discussed experimentally as well as theoretically.
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  • Choshiro TAMURA, Shunzo OKAMOTO
    1998 Volume 74 Issue 1 Pages 12-17
    Published: 1998
    Released: October 17, 2006
    JOURNALS FREE ACCESS
    In response to lessons learned from the damage to structures in the epicentral area of the Hyogo-ken Nanbu Earthquake of 1995, the high-density installation of seismometers has been carried out in Japan. These seismometers have provided the intensities of many subsequent earthquakes. This paper presents a report on the results of the analysis of earthquake intensities observed in and around the epicentral areas of six magnitude 6 class earthquakes in the four areas.
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  • Takeshi FUKUSHIMA, Mika SHIRAO, Hideaki ICHIHARA, Tomofumi SANTA, Hiro ...
    1998 Volume 74 Issue 1 Pages 18-23
    Published: 1998
    Released: October 17, 2006
    JOURNALS FREE ACCESS
    The present study was intended to confirm the idea that D-aspartic acid (Asp) in pineal and pituitary glands could originate from diet as suggested by our previous report [Imai et al. (1997) Proc. Japan Acad. 73B, 48-52]. When the rats were kept under fasting for 2 or 3 days, the levels of D-Asp, but not L-Asp in these glands were significantly lower as compared with those in the rats with diet. The fact suggests that D-Asp in these glands is derived from the exogenous origin. Next, we determined the D- or L-Asp concentration in these glands (at 30min, 3hr and 24hr) and plasma (2min-5hr) following intravenous administration of D- or L-Asp (50mg/kg) into rats. D-Asp concentrations remarkably increased after administration of D-Asp, and the levels were almost constant from 30min to 24hr after administration, indicating that D-Asp was accumulated and deposited in these glands. In contrast, no accumulation of L-Asp was observed in case of L-Asp or D-Asp administration. In plasma, either D- or L-Asp concentration decreased to the normal level at 3hr after the administration of the respective enantiomers, although different half-lives for D- and L-Asp in plasma were obtained; 7.84min for D- and 3.75min for L-Asp. These results indicate that D-Asp incorporated from extracellular fluids into pineal and pituitary glands is difficult to be metabolized and eliminated, and strongly support the idea that the D-Asp in these glands in vivo is derived from the exogenous source, such as dietary D-Asp.
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