We have constructed a reliable and inexpensive apparatus useful for measuring environmental ionizing radiations. Electronic pocket dosimeter (EPD) “MYDOSE MINI E” (Model PDM-101 ; Aloka, Tokyo, Japan) was connected to a power supply made of solar batteries andNiCdbatteries. The apparatus was placed in a container made of acrylic board and was attached to a pole of 1 m long Using such apparatus (monitoring posts), we began to measure environmental ionizing radiations at three spots near Okayama city. Here, we describe technical specifications of the apparatus (The data obtained using these apparatus will be presented elsewhere) .
For safety evaluation of diphenyl, a food additive, in Japan, labeled Biphenyl was synthesized by reaction of thallium (I) bromide with phenylmagnesium bromide which is prepared from bromobenzene-U-14Cin ether. The formation of labeled diphenyl in high yield made it possible to study the binding of diphenyl to mouse hepatic microsomes. Diphenyl with high specific activity formed the covalent binding to microsomes after metabolic activation. However, effects of two inducers, benzo (a) pyrene and KC-500, on the binding activitiy of diphenyl were not clear under our experimental conditions. The data reported here seem to be valuable from the view point on safety evaluation on food additives.
Zeolite, one of the inorganic ion exchangers, is expected to be an eliminant for the incorporated54Mn.In this study, effect of the manganese concentration and several coexisting metal ions on the adsorption of54Mn to zeolite was examined in vitro. In manganese chloride solution, zeolite adsorbed54Mncompletely within its ion exchage capacity of 5.48 meq/g. The adsorption of54Mnwas also measured in several mixed solutions containing manganese chloride and another metal salt. It was slightly suppressed with sodium, magnesium, and potassium; strongly suppressed with copper, strontium, and cerium. Separation factors of zeolite estimated with these results were as follows in the affinity order: copper>strontium>caesium, cerium, zinc>calcium>iron (II) >manganese, cobalt>potassium>sodium>magnesium. These results suggest that zeolite is a useful agent for eliminating the incorporated54Mnand it may be also effective for strontium and caesium owing to their high separation factors.
The gamma irradiation effect on the state of water in Tetrahymena pyriformis was studied by1H-NMR. The spin-lattice relaxation time (T1) value was measured, in which the transient spectra after 180° pulse were observed varying pulse interval (PI) . This method revealed the appearance of another small peak of water together with the main peak of water in irradiated cells, whereas any small peak of water was not observed in unirradiated cells. The T1value of the small peak was short compared with that of the main peak, suggesting that the water corresponding to the small peak is different from that corresponding to the main peak.