[en] The carbon and nitrogen isotope ratios of Hypomesus transpacificus (a pond smelt) in a eutrophic lake, Lake Suwa, were measured from April to September in 1986 and 1987. The differences in the isotope ratios between these two years were observed. The stable isotopes were transferred from phytoplankton to zooplankton and pond smelt, associated with organic matters. Therefore, the difference in the isotope ratios in two years seemed to reflect the differences of the proceeding of primary production. It was suggested that the carbon and nitrogen isotope ratios of animal, whose trophic level is far from primary producer, can be the qualitative indicators for assessing the primary production in a lake ecosystem. (author)

[en] Evaluation was made for carbon and nitrogen stable isotope analyses of amino acids which were hydrolyzed from biological samples. Alteration of isotopic compositions during chemical preparations was studied in incorporation with organic solvent, acid hydrolysis, and ion-exchange chromatography. Based on such assessment, analyses of isotope compositions of single amino acids were made for collagen and plant protein. The carbon isotope composition of soybean showed consistent pattern with algal amino acids. Similarity was also found in the intermolecular relationship of δ¹³C and δ¹⁵N between collagen and soybean protein. (author)

[en] Noble gas isotopic compositions and concentrations were measured for two monomict eucrites Yamato-791186 and -792510 and for three polymict eucrites Yamato-791960, -791962 and -792769. Terrestrial ages calculated on the concentrations of cosmogenic radionuclide ⁸¹Kr are in the range of 0.23-0.35 Ma, which are older than those reported for Yamato meteorites including eucrites. The noble gas result suggests that the monomict eucrites, Y-791186 and Y-792510, and the polymict eucrites, Y-791960 and Y-791962, are paired. If shielding effect on the cosmogenic ⁷⁸Kr/⁸³Kr ratio was considered, the preatmospheric radius of Y-791186 and Y-792510 was estimated to be small (about 10 cm in diameter). It was also calculated that Y-791960 was near the surface and Y-791962 was at the center of a preatmospheric body of about 1m in diameter. At least five pairs are identified for eucrites in the Yamato ice field referred to the published data. (author)

[en] A new method of accurate determination of isotopic composition and concentration of a strontium-84 spike solution was devised for simultaneous determination of strontium contents and isotopic compositions in rocks and minerals by measuring strontium isotopic ratios in spiked samples. In this method, the isotopic composition of strontium in the spike were determined so as to minimize the sum of squares of deviations of spike strontium-84 concentrations which were calculated from measured isotopic ratios of strontium in five different mixtures of the spike and the standard solution. The method can eliminate all mass discriminations occurred during the measurements on a surface ionization mass spectrometer. The results were tested by measuring ⁸⁷Sr/⁸⁶Sr ratios of Eimer and Amend SrCO₃ and JB-1 geochemical reference material, and by determining the strontium content in JB-1. The measurements of strontium isotope ratios in spiked samples give average values of 0.708007±0.000052 and 0.70417±0.00004 for ⁸⁷Sr/⁸⁶Sr ratios of E and A SrCO₃ and JB-1, respectively. The strontium content in JB-1 was estimated at 457.1±1.3 ppm. These values are very close to reported respective values. (author)

[en] Metabolism of cianidanol (I) in rats and dogs was investigated by a method which couples capillary GC/MS and deuterium labelling procedures. A difference was observed in the urinary metabolites of I between the two species; in the case of rats, 3'-O-methylcianidanol (II), δ-(3,4-dihydroxyphenyl)-γ-valerolactone (III), δ-(3-methoxy-4-hydroxyphenyl)-γ-valerolactone (IV) and δ-(3-hydroxyphenyl)-γ-valerolactone (V) were identified as the metabolites of I, whereas in dogs the main metabolite was II. (author)

[en] Fragmentation mechanism of p-cyanobenzoic acid isopropyl ester, in particular, that of the intermediate ion, [CNC₆H₄COOH₂]⁺ (m/z 148), generated by double hydrogen migrations, is investigated by using deuterium labelling technique and mass analyzed ion kinetic energy (MIKE) spectrometry. It is demonstrated that the intermediate ion has a protonated p-cyanobenzoic acid structure with the hydrogen atom on the carbonyl group. (author)

[en] We have constructed a mass spectrometer system for noble gas isotopes. This system consists of a noble gas extraction and purification system for an extremely small amount of extraterrestrial sample and a conventional (30 cm radius, 90deg magnetic sector) single focus mass spectrometer, which are made of stainless steel. The sample is heated in a small tungsten basket. Extracted noble gases are purified by hot Ti-Zr getters and a getter pump. The mass spectrometer is controlled by a personal computer to obtain high precision. The computer is connected with a programmable voltage current source and digital multimeters through GP-IB interface. The computer controls these instruments and the isotope data are recorded on a floppy disk. The software was developed with N88-basic (86). In order to improve the system sensitivity, ion counting method was introduced. The number of ions is counted with a multichannel scaler by means of a constant fraction circuit. (author)

[en] Size distributions of Pb, Bi, and Mo clusters produced by Xe ion bombardment have been measured by a deflection type mass spectrometer. In general, the ion intensity decreases with increasing cluster size n. Superimposed on this gradual decrease with n, some anomalies have been observed in the cases of Pb and Bi. No prominent anomaly for Mo clusters has been observed. A correlation is found between the size distribution of clusters produced by Xe ion bombardment and that produced by inert gas condensation method. (author)

[en] By means of three isotope tracer techniques, proportion of direct runoff and characters of groundwater runoff were studied in the Iwami River drainage during a high runoff period for about 3 days, caused by a heavy rainfall of 85 mm for 17 hours. The proportion of direct runoff is 15 % or less of the total runoff caused by the rainfall, while 65 % of river water at the peak of runoff. Differences observed in the runoff manners among ¹⁸O, ²H, and ³H are interpreted as a result of preferential runoff of previous precipitations stored in some unsaturated zone above the saturated groundwater zone. Cl^- content is not conservative as a tracer to study runoff mechanisms. (author)

[en] In order to examine weathering effects on chondritic meteorites in Antarctic and non-Antarctic environments, the Rb-Sr isotopic ratios and abundances of REE, Ba, Sr, Rb, and K were determined for 8H-group chondrites (Yamato-790986 [H3], Yamato-74492 [H3], Grady [H3], Brownfield [H3], Clovis (No.1) [H3], Yamato-74155 [H4], Allegan [H5] [one whole-rock and two chondrules], and Yamato-74371 [H5]), and partly for the Etter (L5) chondrite. The Allegan whole-rock shows a flat REE pattern with a large negative Eu anomaly and Sr depletion. Analyses of Rb-Sr systematics of one whole-rock and two chondrules show somewhat younger age 4.38±0.12 b.y. It is suggested that REE and Rb-Sr were redistributed during the early thermal metamorphism. Except for Allegan, most other H-chondrites (finds) show the perturbation of the Rb-Sr systematics, indicating recent loss of Rb. It was found that the weathering degree is related with the Rb-Sr disturbance in Antarctic H-chondrite. In spite of different degrees of weathering, all the Antarctic H-chondrites studied (including heavily weathered ones) show flat REE patterns normal as H-chondrite with occasional occurrence of minor Eu anomalies, indicating the tough resistance of REE in H-chondrites to the Antarctic weathering. On the other hand, non-Antarctic finds (particularly the weathered chondrites) indicate light-REE enriched patterns with a large negative Ce anomaly and extreme enrichment of Ba, suggestive of terrestrial contaminations. (author)