Biosyntehsis of13C-labeled starch was examined by using a small-scale apparatus. Tobacco leaves were placed in the cylindric photosynthesis chamber (14φ×50 cm) . After preincubation for 30 h in the dark, incubation with13C-labeled CO2was carried out for 48 h under irradiation with fluorescent lights. Labeled starch was extracted from the leaves and was purified. About 500 mg of13C-labeled starch can be obtained from 50 g of the leaves. The13C-abundance of the starch formed by the incubation was determined to be 82.0-92.0 atom % by mass spectrometry.
The variations of environmental gamma radiation flux were observed by using a new portable spectrometry recording system for 1 year. Spectrum analyses by the response matrix method have provided much information, and the artificial contribution can be separated from natural back ground dose by using the Thmethod or the three component method.
Chemical constituents of the commercially available “biodegradable” liquid scintillator solvents were elucidated by means of GC/MS analysis etc, as either the mixture of monosubstituted benzenes with the alkyl chain of carbon 10 to 13, or 1- (3, 4-dimethylphenyl) -1-phenylethane.