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- Author or Editor: T. Matsushita x
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Summary
The time dependences of the thermal power of aqueous myoglobin solutions were measured by microcalorimeter at 298.15 K. Exothermic reactions occurred in aqueous myoglobin solutions due to the metabolism of aerobic microbes, and these roughly consisted of four phases. The generation times obtained were about (555) min for the logarithmic exothermal reaction phase. The total energies were considerably dependent on the amount of oxygen present, suggesting strongly that the exothermic reaction was caused by aerobic microbes. The apparent thermal metabolic rates were positively dependent on the concentration of myoglobin, probably because of the effects of myoglobin as a food source and/or as a donor of oxygen.
Abstract
Excess enthalpies of six binary mixtures of CH3 OD+CH3 OH, CH3 OD+CD3 OD, CD3 OD+CH3 OH, C2 D5 OD+C2 H5 OH, C2 D5 OD+C2 H5 OD, C2 H5 OD+C2 H5 OH have been determined over the whole range of mole fractions at 298.15 K in order to know the isotopic effect on hydrogen-bonding accurately, although there are many reports on the differences in the strength of hydrogen-bonding between OH and OD. All excess enthalpies measured are very small and endothermic. The mixtures of CH3 OD+ CH3 OH, and C2 D5 OD+C2 H5 OH showed the largest excess enthalpies among each methanol and ethanol mixtures. The difference of intermolecular interaction between OH and OD in methanol and ethanol was almost same value of (1.820.04) J mol-1 Excess enthalpies of 1,4-dimethylbenzene+1,3-dimethylbenzene and 1,4-dimethylbenzene+1,2-methylbenzene were measured by three different principle calorimeters at 298.15 K in order to know the precision of calorimetry for a small enthalpy change.
Excess molar heat capacities of (L-glutamine aqueous solution+D-glutamine aqueous solution) were determined by using a differential scanning calorimeter at temperatures between 293.15 and 303.15 K. Excess molar heat capacities are all negative. Excess molar heat capacities decrease with increasing temperature.
Abstract
The heat capacities of binary aqueous solutions of 1,2-ethanediol, 1,2-propanediol and 1,2-butanediol were measured at temperatures ranging from 283.15 to 338.15 K by differential scanning calorimetry. The partial molar heat capacities at the infinite dilution were then calculated for the respective alkanediols. For 1,2-ethanediol or 1,2-propanediol, the partial molar heat capacities at the infinite dilution of increased with increasing temperature. In contrast, the partial molar heat capacities of 1,2-butanediol at the infinite dilution decreased with increasing temperature. Heat capacity changes by dissolution of the alkanediols were also determined. Heat capacity changes caused by the dissolution of 1,2-ethanediol or 1,2-propanediol were increase with increasing temperature. On the other hand, heat capacity changes caused by the dissolution of 1,2-butanediol are decrease with increasing temperature. Thus our results indicated that the structural changes of water caused by the dissolution of 1,2-butanediol differed from that of the two other alkanediols.
Abstract
Sufficient information on the mechanisms of radiocesium translation from substrate to mushroom and long-term radiocesium accumulation is still not available, though high concentrations of radiocesium were reported in the fruiting bodies of various species of mushrooms especially after the Chernobyl accident. We studied the concentration and existing state of Cs in the cultured mycelium of the edible mushroom (Pleurotus ostreatus (Fr.) Kummer Y-1) using NMR. The133Cs NMR resulting spectra exhibited two resonance signals arising from the mycelium whereas one resonance signal from the external medium and CsCl standard solution. The chemical form of the signal in the downfield found in the only mycelium might be concerned with Cs accumulation in the mycelium.
Abstract
Elemental concentrations in Japanese medaka and mosquitofish collected from uncontaminated rivers in Kumamoto, Japan were analyzed by instrumental neutron activation analysis with k 0 standardization method to know the background levels. A statistical analysis indicated the difference in metal concentrations among rivers and species. Background levels of elemental concentrations in some aquatic insect larvae were analyzed and metal concentrations were different among species, though they were collected at the same point. Enrichment factors of heavy metals in insect larvae were in the order of 103−104 suggesting effectiveness of insect larvae as bioindicator.
