To investigate the measurement of low level gamma-ray dose, 0.1N sulfuric acid solution containing Fe (II) and 59Fe (II) (as a tracer) was irradiated with60Co gamma-rays. An ion exchange column of titanium phosphate was used for separating59Fe (II) from59Fe (III) . The amount of59Fe (III) produced by irradiation was found to increase linearly with radiation dose. C-value was 23.6±0.4. From the experiment it was found, for Fe (II) concentration of 2×10-4M, a fairly good result was obtained within the range of dose of 200-800 cads.
A study has been continued of14C-dating method by liquid scintillation counting. In this technique, sample of either large or small volume can be accomodated, and when using large amount of sample, statistical errors in counting can be made smaller than in the case of gas counting. The authors have been using methanol or methyl-borate containing sample carbon as a solvent of scintillation solution because of ease of synthesis and effectiveness in counting. Firstly, old organic samples were converted, successively, into charcoal, *CO2, (NH4) 2*CO3, and finally, into Ca*CO3. Perchloric acid was poured into the Ca*CO3and*CO2was again evolved. The*CO2was blown into diethyl-carbitol solution of LiAlH4and to produce LiAl (CH3O) 4and then the LiAl (CH3O) 4was decomposed by adding butyl carbitol to obtain methanol. The CH3OH was carefully purified and the purity was verified both by elementary analysis and by gas chromatography. The yield was about 70% of Ca*CO3. The scintillator containing the methanol and toluene in the ratio of 1: 1 showed counting efficiency of 26%. Methyl-borate was also prepared from methanol and B2O3. Counting efficiency of the scintillator containing 60% methyl-borate and 40% toluene was 52%.
Flotation has proven to be effective in removing137Cs from its aqueous dilute solution, with the aid of suitable coprecipitant such as cupric or nickel ferrocyanide and pertinent collector such as sodium oleate and octadecylamine acetate. It has been found in the experiments on single stage flotation that 90-99% of137Cs can be removed by optimum choice of the concentrations of coprecipitant and collector, as well as of pH of flotation medium. Multiple flotation for four successive stages gave decontamination factor of 104to 106with a volume reduction ratio of higher than 50.
Tissues excised from carrot root were X-irradiated and were cultivated in vitro. Fresh weight, DATA, RNA or protein content were measured during 21 days after irradiation. The increase of DNA amount was not found, while fresh weight and protein content increased during 21 days. Histological observation demonstrated that there were no “meristematic” regions and the cells enlarged and became conspicuously vacuolate.
Blasticidin S, an agricultural antibiotic effective against Piricularia oryzae, induces the diarrhoea and the severe inflamation of skin and mucous memblane exposed to the antibiotic. To know the movement or the distribution of Blasticidin S in vivo, we labeled it with tritium gas, so called Wilzbach's method. Tritiated Blasticidin S was not dissolved, testing with chemical and biological method. We measured the radioactivity of tritium in the several organs or blood of mice after oral administration and intravenous administration of tritiated Blasticidin S. The radioactivity of tritium in blood decreased rapidly 24 hours after the administration, while that of tritium in organs decreased rather slowly. The radioactivity of tritium in the blood was equally observed in the several organs after oral administration of tritiated Blasticidin S, while that of tritium in organs was selectively seen in the kidney after intravenous administration.