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Volume 5, Issue 2
Displaying 1-8 of 8 articles from this issue
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Tamiko IWASAKI1964 Volume 5 Issue 2 Pages 91-96
Published: June 01, 1964
Released on J-STAGE: August 29, 2006
JOURNAL FREE ACCESSThis investigation was carried out to clarify the relationship between radiosensitivity and the water content of the hydrated eggs. Prior to γ-irradiation the water content of Artemia eggs was modified by hydrating at 0°C and 27°C for one to seven hours. At three hours after hydration, the water content reached a plateau at both temperatures.
The eggs became more radiosensitive in the wet state than in the dried state. By irradiation with 100 kr, the hatchability of eggs hydrated at 0°C and 27°C did not show noticeable difference by prolonged hydration. On the other hand, the radiosensitivity of eggs irradiated with 200 kr steeply increased after one hour hydration at both temperatures. Further hydration at 0°C maintained this level of radiosensitivity, but at 27°C showed the complex pattern. The patterns of increased sensitivity is related to the temperature of the steeping water and may be associated with physiological or developmental stage of the treated eggs.View full abstractDownload PDF (245K) -
Tamiko IWASAKI1964 Volume 5 Issue 2 Pages 97-101
Published: June 01, 1964
Released on J-STAGE: August 29, 2006
JOURNAL FREE ACCESSThe change in the extent of biological damage for a given dose by storage after irradiation is called the after-effect. The purpose of the present study is to compare the after-effect between irradiation and heat-treatment.
Artemia dry eggs were exposed to γ-rays (120, 240, 360, 480 and 600 kr) or high temperature (at 100°C for 30, 60, 90 and 120 minutes) and stored at room temperature for varying time (0, 1, 3, 7 and 30 days) after treatment. After the storage period, the eggs were soaked and their hatchabilities were scored at 72 hours after.
Post-irradiation storage of irradiated eggs resulted in a notable decrease in hatchability, and the rate of decrease was much greater in the eggs given higher doses than in those lower ones. On the contrary, storage of heat-treated eggs did not show such an aftereffect.
From this series of experiment, it may be concluded that in its nature the damage induced by irradiation is different from that by heat-treatment.View full abstractDownload PDF (217K) -
Yoshio HIYAMA, Hiroshi HAYAMI, Noboru YAMAGATA, Tamiya ASARI1964 Volume 5 Issue 2 Pages 102-112
Published: June 01, 1964
Released on J-STAGE: August 29, 2006
JOURNAL FREE ACCESSAfter the previous report (ref. 1), two types of survey on the contamination of food by fall-out in Japan were carried out. The one is the standard diet survey, in which food materials were purchased at 4 localities according to the same standard recipe 4 times a year and radioassayed for 90Sr and 137Cs. Since the autumn of 1961, the food materials collected were divided into 7 groups (cereals ; pulses, nuts and fruits: leafy vegetables ; root vegetables ; sea weeds ; fish and shellfish; and milk, meat, eggs and poultry;) to know about the size of role of these food groups in human body contamination. The other is the daily diet survey, in which one day amount of diet of 10-20 families selected at random in each of 7-10 localities in Japan twice a year.
The results obtained by the two methods were compared with each other. Both showed similar tendency as general. However the values were always higher in daily diet survey than standard diet survey (Fig. 1).
The results of both surveys show generally that vegetables are major source of both 90Sr and 137Cs in Japan in most cases and the milk is entirely minor source of contamination (Table 1). The both survey results were always higher in Japan sea side than in Pacific side in contaminated level (Figs. 2-6). And it seems to be no difference between urban and rural. The relationships between the contamination level of diet and that of fall-out rate and deposited were estimated, using the values of standard diet in Tokyo.View full abstractDownload PDF (316K) -
Fumio YAMASAKI, Masaharu OKANO, Teruaki NAGAHARA, Hironobu WATANABE1964 Volume 5 Issue 2 Pages 113-115
Published: June 01, 1964
Released on J-STAGE: August 29, 2006
JOURNAL FREE ACCESSExternal doses of radiation from fall-out materials are observed in three different places in Tokyo and its vicinity. Scintillation counter and ionization chamber are used as radiation detectors. Monthly doses observed in these six years revealed that external radiations are mostly come from nuclides with intermediate half-lives, and their values exceeded the level of dose rate due to natural radioactive substances for the period of 22 months begining October 1961.View full abstractDownload PDF (104K) -
Kiyoshi KODAIRA1964 Volume 5 Issue 2 Pages 116-119
Published: June 01, 1964
Released on J-STAGE: August 29, 2006
JOURNAL FREE ACCESSIn Japan, Sr-90 in brown rice showed two peaks at October 1959 and October 1962, whereas Sr-90 in polished rice showed almost constant level, and quite less contamination. Cs-137 contamination was roughly 10 times of that of Sr-90 in polished rice. This ratio is higher than that of fall-out itself, which has been estimated as around 3.
A discussion was made on the mechanisms, which can be important factors to give rise such a high Cs-137 contamination of polished rice: characteristic effect of NH+4 ion on the liberation of Cs+ ion from flooded rice soil, rate of absorption of Cs and Sr by plant roots as well as plant body surfaces, and rate of translocation of Cs and Sr in plants.View full abstractDownload PDF (148K) -
Masamichi SAIKI, Taku KOYANAGI, Giichiro TANAKA, Akio TOMIKAWA1964 Volume 5 Issue 2 Pages 120-123
Published: June 01, 1964
Released on J-STAGE: August 29, 2006
JOURNAL FREE ACCESSMesurements were made on the 90Sr content in human bone samples from subjects who died during the period from 1961 to October 1963 in Japan. The most remarkable accumulation of 90Sr in human bone was found in 0-4 year age group. Considerable increases with time in the S. U. (90Sr pc/g Ca) value was also found in this group.View full abstractDownload PDF (115K) -
Kunihiko KIGOSHI1964 Volume 5 Issue 2 Pages 124-130
Published: June 01, 1964
Released on J-STAGE: August 29, 2006
JOURNAL FREE ACCESSThis paper presents the variation of atmospheric carbon-14 concentration in Tokyo since the end of 1959. The observed results show big random fluctuation compared with those obtained by Fergusson (1963) at California. This fluctuation is discussed on the view of the nature of air mass on Honshu Island. Based on the variation of the tropospheric content of carbon-14 since 1955, the transport of carbon dioxide from the atmosphere into sea water is discussed using a parallelism between the supplies of carbon-14 and other radionuclides produced by nuclear tests from the stratosphere into the troposphere.View full abstractDownload PDF (233K) -
Tomokichi TSUGO, Hiroshi NOZAKI, Tamiya ASARI, Noboru YAMAGATA1964 Volume 5 Issue 2 Pages 131-137
Published: June 01, 1964
Released on J-STAGE: August 29, 2006
JOURNAL FREE ACCESSIn succession of the previous report (1), the measurements of strontium-90 (Sr-90), cesium-137 (Cs-137) and iodine-131 (I-131) concentrations in milk were carried out in order to evaluate the range of the radioactive contamination of milk in Japan since 1961. Farm milks collected from various districts of Japan monthly from 1961 to 1963 were used for radioactivity assay. The results of observation show the Sr-90 concentration in milk is higher than that in the previous years (1957-1960) all over the country and there is regional variation in Sr-90 and Cs-137 concentrations.View full abstractDownload PDF (228K)
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