RADIOISOTOPES
Online ISSN : 1884-4111
Print ISSN : 0033-8303
ISSN-L : 0033-8303
Volume 49 , Issue 6
Showing 1-8 articles out of 8 articles from the selected issue
  • Hiroshi IMAIZUMI, Hideyuki SAKAI, Naoki KANO
    2000 Volume 49 Issue 6 Pages 285-291
    Published: June 15, 2000
    Released: March 10, 2011
    JOURNALS FREE ACCESS
    In order to reveal the reactivity of each functional group in the compound having three functional groups per molecule, the hydrogen-isotope exchange reaction (T-for-H exchange reaction) between disubstituted phenol and tritiated water vapor (HTO vapor) was dynamically observed at 50, 60, and 70°C in a gas-solid system. The data obtained in the observation increased with increasing observed time, and it was found that T-for-H exchange reaction occurred. Applying the A″-McKay plot method to the data obtained, the reaction was dynamically analyzed. The rate constant (k) of each functional group for the reaction was consequently obtained. These k's obtained and k's obtained previously were compared with each other. When the additive property of the Hammett rule was applied to the k's obtained in this work, the new substituent constants were obtained. The new constants were fitted on the Hammett plot obtained previously. From the above-mentioned, the following five matters have been clarified. (1) The reactivity of different functional groups can be compared with each other by applying the method used in this work. (2) The reactivity of the functional groups can be dynamically analyzed, and the A″-McKay plot method is useful to analyze the reactivity. (3) The additive property of the Hammett rule, which is generally used in the field of organic chemistry in order to compare the chemical reactivity of organic materials, is applicable to quantitative comparison of the reactivity of the functional groups. (4) The reactivity of the functional groups can be simultaneously (and unchangeably) analyzed by using the T-for-H exchange reaction. (5) The method used in this work is useful to analyze the reactivity of a material having many kinds of functional groups.
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  • Takahiro MATUMOTO, Hirokazu MIYOSHI, Kazuo SATOU, Taro KISHI, Tomio YO ...
    2000 Volume 49 Issue 6 Pages 292-297
    Published: June 15, 2000
    Released: March 10, 2011
    JOURNALS FREE ACCESS
    The accumulation process in bone of 99mTc-hydroxymethylene diphosphonate (99mTc-HMDP) and 99mTc-methylene diphosphonate (99mTc-MDP) was examined on 9 subjects (5 for 99mTc-HMDP and 4 for 99mTc-MDP) . 99mTc compounds in blood were analyzed with radio-thinlayer chromatography, radioactivity was measured using a scintillation counter, and the uptake of both 99mTc diphosphonates in bone was examined by sintigraphy. The amounts of 99mTc-HMDP and MDP compounds disappeared from blood for 2h after injection were 83% and 87%, respectively, and these were almost unchanged even after 3h. While the greater part of 99mTcO-4 contained in both diphosphonates was disappeared from blood, the small amounts of unknown 99mTc compounds were produced in blood. The ratio of the radioactivity of 99mTc-HMDP in lumbar vertebra to soft tissue near bone was 1.5±0.5 after about 3h, showing that equilibrium occured in the process of the accumulation in bone, and good scintigrams were depicted in all the cases.
    These results suggest that the accumulation in bone of both 99mTc diphosphonates may be by both fast chemical adsorption onto the surface of the hydroxyapatite in bone and slow uptake mediated through osteoblast-like cells and organic matters.
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  • Ayako NAKAMURA, Toyotsugu YAMANO
    2000 Volume 49 Issue 6 Pages 298-304
    Published: June 15, 2000
    Released: March 10, 2011
    JOURNALS FREE ACCESS
    A new concept called 1cm dose equivalent rate constant with shielding effect is introduced for estimation of radiation dose. This new concept represents an expansion of the former standard 1 cm dose equivalent rate constant (defined as μSv·m2·MBq-1·h-1) adjusted attenuation for any given thickness of shielding material (iron, lead and concrete) . The 1cm dose equivalent rate constant with shielding effect for various shielding conditions can be rapidly computed with a free-software application, KINGS-B621, which may be easily downloaded from the internet. The computed rate constants can be put out as text files which are compatible with commercially available spread-sheet software, so it is easy for users to apply the data to creation of documents concerning radiation dose.
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  • Hiroshi BABA
    2000 Volume 49 Issue 6 Pages 305-317
    Published: June 15, 2000
    Released: March 10, 2011
    JOURNALS FREE ACCESS
    History of the synthesis and discovery of heavy elements starting from 93 is reviewed. This article describes the story of thrilling competition for the discovery of new elements with increasing difficulties as the atomic number increases, beginning the 93 element, neptunium. Particularly, competition between USA and USSR has lasted from 102 to 106 element and was unsettled until a new aspect was developed in relation with the superheavy elements theoretically predicted. Here, the search of naturally occurring superheavy elements is briefly explained as an introduction to the present and future perspectives of the research on the superheavy elements which is appearing in the succeeding article.
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  • [in Japanese]
    2000 Volume 49 Issue 6 Pages 319-322
    Published: June 15, 2000
    Released: March 10, 2011
    JOURNALS FREE ACCESS
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  • [in Japanese]
    2000 Volume 49 Issue 6 Pages 323-324
    Published: June 15, 2000
    Released: March 10, 2011
    JOURNALS FREE ACCESS
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  • [in Japanese]
    2000 Volume 49 Issue 6 Pages 325-327
    Published: June 15, 2000
    Released: March 10, 2011
    JOURNALS FREE ACCESS
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  • [in Japanese]
    2000 Volume 49 Issue 6 Pages 329-331
    Published: June 15, 2000
    Released: March 10, 2011
    JOURNALS FREE ACCESS
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