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Volume 37 (1996)
- Issue 4 Pages 235-
- Issue 3 Pages 151-
- Issue 2 Pages 71-
- Issue 1 Pages 1-
Volume 37, Issue 2
Displaying 1-6 of 6 articles from this issue
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YUTAKA TATEDA, TAKU KOYANAGI1996 Volume 37 Issue 2 Pages 71-79
Published: June 15, 1996
Released on J-STAGE: March 28, 2006
JOURNAL FREE ACCESSConcentration factors (CFs; Bq kg-1 in wet fish muscle/Bq kg-1 in filtered seawater) for 137Cs were determined in Japanese coastal fish collected from 1984 to 1990. 137Cs/Cs (stable) atom ratios were also examined to clarify the distribution equilibrium of 137Cs between marine fish and seawater. The geometric mean of CF in Japanese coastal fish was 52±4 (standard error of the mean), with values ranging from 14 to 133. 137Cs/Cs atom ratios both in marine fish and seawater indicate that the distribution of 137Cs was in equilibrium between fish muscle and seawater. Therefore, CF values obtained in the present study can be regarded as equilibrated. Our results show that the CFs for 137Cs in Japanese coastal fish were within the range of Japanese guidelines, but were below the recommended IAEA value.View full abstractDownload PDF (377K) -
ASAYA KOBASHI1996 Volume 37 Issue 2 Pages 81-95
Published: June 15, 1996
Released on J-STAGE: March 28, 2006
JOURNAL FREE ACCESSThe radioactivities of the naturally occurring radionuclides (226Ra, 228Ra, 228Th and 40K) and a fallout nuclide (137Cs) in books produced in Japan in the 20th century were measured by gamma-ray spectrometry to obtain information on radiation emitted from books. The respective concentration ranges of 226Ra, 228Ra, 228Th, 40K, and 137Cs were 0.2-6.4, 0.4-11.2, 0.3-11.3, 1-112, and 0-3.6 Bq kg-1. X-ray diffraction spectra of the papers used in book printing showed that pyrophyllite, talc, kaolinite, and calcium carbonate were contained as fillers. A comparison of the radioactivity contents of the pulp and filler indicated that most of 226Ra, 228Ra, and 228Th in the books was present in the filler whereas 137Cs was in the pulp. The pattern of the concentration of each nuclide vs. the year of issue of the book was investigated. Patterns for the naturally occurring radionuclides were similar and were explained by the kinds of filler used. The pattern for 137Cs differed from the patterns of the naturally occurring radionuclides, having a marked peak in the mid-1960s.View full abstractDownload PDF (679K) -
Dosimetry of Mixed Neutron and Gamma Radiation with Paired Fricke Solutions in Light and Heavy WaterMUMINJAN HIMIT, TETSUO ITOH, SATORU ENDO, KAZUO FUJIKAWA, MASAHARU HOS ...1996 Volume 37 Issue 2 Pages 97-106
Published: June 15, 1996
Released on J-STAGE: March 28, 2006
JOURNAL FREE ACCESSPaired Fricke solutions, made up from light water or heavy water and 0.8N in H2SO4 and 1mM in Fe(NH4)2(SO4)2 and NaCl, were calibrated with 60Co γ rays and with mixed neutron and γ radiation from a 252Cf source. Absorbance increases, AL and AH, in light- and heavy-water Fricke dosimeters, respectively, increased with fast-neutron and γ-ray tissue doses, Dn (Gy) and Dγ (Gy), of the mixed radiation as follows: AL=0.00178Dn+0.00371Dγ; AH=0.00121Dn+0.00442DDγ. G-values of 7.2 and 5.5 were obtained for 252Cf neutrons in light- and heavy-water Fricke dosimeters, respectively. When we applied the pair of equations to AL and AH values observed after exposure to mixed radiation in a nuclear reactor, resulting Dn and Dγ values agreed within 10% to doses measured with paired ionization chambers. Doses required for Fricke dosimeters were 5 Gy or more. In contrast, we found that micronuclear yields in onion roots can measure the neutron component of mixed radiation fields at the order of 10 cGy with reasonable accuracy even if the neutron to γ-ray dose ratio is unknown.View full abstractDownload PDF (404K) -
HITOSHI AYAKI, RYUJIRO HARA, MITUO IKENAGA1996 Volume 37 Issue 2 Pages 107-116
Published: June 15, 1996
Released on J-STAGE: March 28, 2006
JOURNAL FREE ACCESSThe rate of ribosomal RNA (rRNA) synthesis was analyzed at different times after ultraviolet light (UV) irradiation in normal human, xeroderma pigmentosum (XP) and Cockayne syndrome (CS) cells. In normal cells, the rate of rRNA synthesis, as measured by the incorporation of 3H-uridine into 18S and 28S rRNAs, decreased immediately after UV irradiation to about half of that of unirradiated cells, and then recovered significantly at 24 h after UV. However, the rate of synthesis continued to decrease during post-UV incubation in XP cells belonging to groups A, D, E, F and G, as well as in CS cells of groups A and B. In contrast, group C XP cells showed a slight recovery at 24 h after UV, suggesting that they have the capacity to repair UV lesions in rRNA genes.View full abstractDownload PDF (450K) -
TAKERU MINAMISAWA, KOUICHI HIROKAGA1996 Volume 37 Issue 2 Pages 117-124
Published: June 15, 1996
Released on J-STAGE: March 28, 2006
JOURNAL FREE ACCESSThe open field activity of first generation (F1) hybrid male C57BL/6×C3H mice irradiated with γ-rays on the 14th day of gestation was studied at the following ages: 6-7 months, 12-13 months and 19-20 months. Doses were 0.1 Gy or 0.2 Gy. Open field activity was recorded with a camera. The camera output signal was recorded every sec through an A/D converter to a personal computer. The field was divided into 25 units of 8 cm square. All recordings were continuous for 60 min. The time which the 0.2-Gy group recorded at 6-7 months, spent in the 4 squares in the corner fields was high in comparison with the control group at the same age. The walking distance of the 0.1-Gy group recorded at 12-13 months was longer than that for the age matched control group. No effect of radiation was found on any of the behaviors observed and recorded at 19-20 months. The results demonstrate that exposure to low levels of γ-rays on the 14th day of gestation results in behavioral changes, which occur at 6-7 and 12-13 months but not 19-20 months.View full abstractDownload PDF (345K) -
I. SATO, N. MATSUSAKA, H. KOBAYASHI, Y. NISHIMURA1996 Volume 37 Issue 2 Pages 125-132
Published: June 15, 1996
Released on J-STAGE: March 28, 2006
JOURNAL FREE ACCESSSeveral parameters of 54Mn metabolism were noted in mice maintained on diets with manganese contents of 80 to 8000 mg/kg. Excretion of 54Mn was promoted as the dietary manganese contents increased. Clearance of 54Mn from the liver, kidneys, pancreas, and spleen was markedly accelerated by feeding mice a high-manganese diet, but clearance from the muscles, femurs, and brain was relatively insensitive to the dietary managanese. Manganese concentrations in the tissues were regulated homeostatically upto the dietary manganese content of 2400 mg/kg, but marked accumulations of manganese occurred when mice were given 8000 mg/kg diet. No toxic symptoms were found up to the 2400 mg/kg diet, but consumption of the 8000 mg/kg diet was less than for other diets. These results suggest that an oral intake of excess manganese is effective for promoting the excretion of 54Mn from a body contaminated with this isotope.View full abstractDownload PDF (315K)
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