The half-life of87Rb was measured by a liquid scintillation method according to the efficiency tracing method. The measuring sample of rubidium chloride was dissolved in a scintillation cocktail of Insta-gel, and the rubidium was determined by gravimetry as tetraphenylborate. The result was (5.56±0.025) ×1010years.
A simple method for the measurement of222Rn in air was established. At first step radon daughters in air were eliminated from air by suction using glass fiber filter, after that the air were introduced directly to the scrubbing bottle filled with seintillator based on toluene and bubbled until the concentration of 222Rn in liquid scintillator reached equilibrium state. Then 120m1 of the bubbled liquid seintillator were sealed in the teflon vial for the measurement of radioactivity. After the radioactive equilibrium between222Rn and its daughters were reached, the radioactivity were measured by the low background liquid scintillation counter. The detection limit of222Rn in air by this method was 3×10-3Bq/l air (8×10-14Ci/l air) . Though alpha spectrometry by multi-channel analyzer was also achieved, the integral counting method was used more effectively. This method was effectively applied to determine the relatively high cocentration of 222Rn in air.
The preparation of alcohol extracts from gamma-irradiated potatoes of the“Danshaku”variety and their chemical aspects were studied. The final concentrate of alcohol extracts from potatoes showed pH values of 3-4. The o-quinones or“radiotoxins” reported by Kuzin, et al. were not detected in the alcohol extracts from potatoes of this variety by high performance liquid chromatography (HPLC) analysis, paper chromatography and the model enzymatic experiment.
The alcohol extracts freshly prepared from gamma-irradiated potatoes were examined for their mutagenic activity in bacterial and mammalian cell systems. Negative results were obtained from all following test systems: Mutation assays with Salmonella typhimurium His- strains such as TA 100, TA 98, TA 1535, TA 1537, and streptomycin-dependent mutant (SMd) strain, TA 100-10, inductests with Escherichia coli strains, K 12 GY 5027 and K 12 C600, chromosomal aberration tests with Chinese hamster cells in culture, as well as micronucleus tests in mice. In addition, no difference in the mutagenic activities was found between extracts prepared from the irradiated and the unirradiated potatoes, suggesting that no mutagenic substance was produced in potatoes following gamma-irradiation.
Radiolysis of bilirubin and cholic acids (cholic acid, desoxycholic acid and lithocholic acid) in hydrous pellet have been investigated with following parameters, which were hydrous content, radiation dose and the dose rate, to discuss the application of r-irradiation for sterilization of crude drug pill involving bezoar bovis. At 774 C/kg (3.0 MR) irradiation for 5% and 10% hydrous contents pellets, the radiolysis percent of those components were less than 5%. However, the higher hydrous pellet, the radiolysis percents of those are more increase. At the same irradiated condition for 20% hydrous contents pellets, the radiolysis percents of those were 15-22%. The hydrous percent of commercial crude drug pill involving bezoar bovis are about 9%, so that the radiolysis of those components will be less than 5% on the sterilization. The radiolysis percent of bilirubin are constant to variation of radiation dose rate between 51.6-722.5 C/kg·hr (0.2-2.8 MR/hr) . But, the values of cholic acids don't definite such as that of bilirubin, bacause of larger analitycal error.
The selective affinity of amino acids for pancreas, due to its high rate of protein synthesis, has prompted us to synthesize new radio-labeled amino acids for pancreatic imaging. Labeling of 19 unnatural amino acids with99mTc was tried in the usual way, and 10 labeled products were obtained with low yields. The highest distribution of radioactivity from all these labeled amino acids, which had been injected intravenously into mice, was found in the kidney, whereas little activity was found in the pancreas. Their low distributions in stomach suggest little dissociation of the labeled amino acids into99mTcO4-in mice. It is presumed that these labeled amino acids behave unlike their original amino acids in the body.