RADIOISOTOPES
Online ISSN : 1884-4111
Print ISSN : 0033-8303
ISSN-L : 0033-8303
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Volume 54, Issue 10
Displaying 1-7 of 7 articles from this issue
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  • The Comparison of Background Subtraction Methods for Low Level Radioactivity in Biological Samples by a Liquid Scintillation Counter
    Norio NOGAWA
    2005 Volume 54 Issue 10 Pages 421-426
    Published: October 15, 2005
    Released on J-STAGE: March 01, 2011
    DOIhttps://doi.org/10.3769/radioisotopes.54.421
    JOURNAL FREE ACCESS
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    The relationship between background count rate and quenching indicating parameters (QIP) is referred as“background quenching curve”in this paper. In the experiment using different quenching level samples containing 3H of 0.83 Bq (50 dpm) or 1.67 Bq (100 dpm), the net count rate was calculated from the measured values by subtracting four different kind backgrounds. The net radioactivity obtained by dividing the net count rate (which is obtained from the background counts and the background quenching curve) by the counting efficiency, was closer to the expected value than those obtained by other three methods.
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  • Radioactivity in Papers: The Concentration and Source of Naturally Occurring Radionuclides
    Asaya KOBASHI
    2005 Volume 54 Issue 10 Pages 427-435
    Published: October 15, 2005
    Released on J-STAGE: March 01, 2011
    DOIhttps://doi.org/10.3769/radioisotopes.54.427
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    The radioactivities of naturally occurring radionuclides (226Ra, 228Ra, 228Th, and 40K) in papers such as magazines, newspapers, and copying papers produced in Japan were determined by gamma-ray spectrometry to obtain information on radioactivity level of papers. The X-ray diffraction measurement of the samples was also carried out to elucidate the source of radionuclides contained in them. The average 226Ra, 228Ra, 228Th, and 40K contents of pocket-sized books were 6.4, 21.5, 23.7, and 18.8 Bq kg-1, respectively, and those of other kinds of samples were near to or less than the values. The 228Th content was generally somewhat higher than the 228Ra content. Possibly 228Ra was leached from the raw materials of the papers to water during their production in preference to 228Th. The concentrations of the naturally occurring radionuclides were correlated to each other. The X-ray diffraction study showed that kaolinite, talc, and calcite were contained in the papers. The kaolinite content of the samples was correlated to the concentrations of the naturally occurring radionuclides, indicating that the naturally occurring radionuclides in the paper samples were mainly brought with kaolinite used as filler or coating pigment in the papers. The regression analysis of the data showed that the natural radioactivity content of filler kaolinite was higher than that of pigment kaolinite.
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  • Radioactivity on the Experimental Notebook of Mme. Curie
    —Collection of Meisei University Library—
    Chizuo MORI, Kazumasa INOUE, Junji MIYAHARA, Kiyoshi CHIWA
    2005 Volume 54 Issue 10 Pages 437-448
    Published: October 15, 2005
    Released on J-STAGE: March 01, 2011
    DOIhttps://doi.org/10.3769/radioisotopes.54.437
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    The contamination with radioactive material of the notebook written by Marie Curie, collected in the library of Melsel University, Tokyo, was studied by use of Imaging Plate to obtain the distribution images of the contamination on the front and back covers, Si detector to obtain the energy spectrum of α-particles from the cover, and HPGe detector to obtain γ-ray spectrum. The distribution images showed that the contamination appeared mainly at the area held with hands, and even the end of the notebook was contaminated. Many dots of the contamination might imply that there were powdery contaminations around her circumstances. Energy spectra of α-particles and γ-rays showed that most of the nuclei were 226Ra and the daughters. The radioactivity level at the intensely contaminated part was just below the permissible level, 4 Bq/cm2, of surface contamination for α-nuclides of Japan. Number of pages written in every month over 15 years was examined for the purpose to imagine the circumstances at that time, and some remarks were given by referring her biographies which include a matter on a Japanese researcher.
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  • Molecular Imaging Research
    Yasuhisa FUJIBAYASHI
    2005 Volume 54 Issue 10 Pages 449-454
    Published: October 15, 2005
    Released on J-STAGE: December 16, 2010
    DOIhttps://doi.org/10.3769/radioisotopes.54.449
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  • A Summary Report on the 26th Quality Control Survey for Immunoassays in Japan, 2004
    Subcommittee for Radioisotope in vitro Test
    2005 Volume 54 Issue 10 Pages 455-507
    Published: October 15, 2005
    Released on J-STAGE: July 21, 2010
    DOIhttps://doi.org/10.3769/radioisotopes.54.455
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  • Uranium, Thorium and Potassium Concentrations in Japanese Soils
    Susumu MINATO
    2005 Volume 54 Issue 10 Pages 509-515
    Published: October 15, 2005
    Released on J-STAGE: July 21, 2010
    DOIhttps://doi.org/10.3769/radioisotopes.54.509
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  • mRNA Degradation and Control of Gene Expression
    Tetsuro YONESAKI
    2005 Volume 54 Issue 10 Pages 517-519
    Published: October 15, 2005
    Released on J-STAGE: July 21, 2010
    DOIhttps://doi.org/10.3769/radioisotopes.54.517
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