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Abstract  

Thermal properties of seed proteins, prolamines from rice, wheat and soybean were studied by differential scanning calorimetry (DSC), thermogravimetry (TG), thermal expansion, X-ray diffraction and infrared spectroscopy. Prolamine films cast from aqueous ethanol are amorphous in the random-coil conformation. The glass transition of prolamine is observed at 160, 172 and 150C for rice, wheat and soybean, respectively. The amorphous prolamine films crystallize at 196, 205 and 199C for rice, wheat and soybean, respectively. The thermal degradation of prolamine films occurs from 228, 250 and 270C for rice, wheat and soybean, respectively.

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Abstract  

Variation of the thermotropic behaviour of both lipid assemblies and associated water molecules with an increase in water content was investigated for negatively charged phosphatidyl-glycerol (PG)-water system up to 90 wt.% water by DSC. The number of water molecules existing in interbilayer regions of the present gel phase was estimated from a deconvolution analysis of ice-melting DSC curves. On the basis of a result of the calorimetric analysis, a water-distribution diagram was constructed over the water content range from 0 to 90 wt.%. The diagram presented a continuous incorporation of interlamellar water up to 90 wt.% water, related to unilamellar-vesicle forming properties of charged lipids. Furthermore, similarly to a result for neutral lipid systems previously reported by us, the present diagram also showed the existence of a specific water content region (i.e., pre-region) where a structural change of planar to curved bilayers for multilamellar structures proceeds with the aid of bulk-like water before finally reaching unilamellar vesicles.

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Abstract  

Macro-porous cation exchange resin Diaion CPK-08 and gel type cation exchange resin Dowex 50WX8 were irradiated with γ-rays from60Co, while soaked in distilled water, 0.5M HNO3 or 4M HNO3, and the ion-exchange properties, such as strong- and weak-acid capacities, moisture content and wet resin volume, were examined in relation to absorbed dose. There was no appreciable difference between the radiation stabilities of the two cation exchangers. Increase of HNO3 concentration reduced the loss of strong-acid capacity and increased the decross-linkage and the weak-acid capacity. Elution characteristics of137Cs and90Sr from columns packed with γ-irradiated resin were examined and the column distribution ratio of these radionuclides and the theoretical plate number were calculated. These values decreased with the increase of absorbed dose. Diaion CPK-08 was packed into a pressurized column and irradiated with γ-rays at a dose rate of 2·106 R/hr, while water was passed through the column at a constant flow rate. The greatest change of the resin properties was observed at an upper stream position from the position of the highest radiation dose of 2·106 R/hr.

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Abstract  

Tritium concentrations were analyzed for coastal seawater and lake water collected from various places in Japan. Low tritium concentrations were observed for coastal seawater of small islands and it was attributed to a short residence time of the ground-water in such a small island. Tritium concentrations in lake water showed a significant variation. And it was revealed that the size of the lake and its drainage area were the dominant factors controlling the tritium concentrations in lakes.

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Abstract  

We measured radiocarbon age of an ancient document “Minamoto no Yoritomo Sodehan Migyosho”. The content tells that it was issued in 1189 by “Minamoto no Yoritomo” known as the virtually first shogun in Japan to grant “Matsugi” family the privilege of controlling craftsmen of foundry industry. Paleographical views, however, suggested that it can be a counterfeit. The radiocarbon dating clarified that the document was written not in the 12th but after the 16th century.

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Physiology International
Authors: M. Nakamura, N. Satoh, H. Tsukada, T. Mizuno, W. Fujii, A. Suzuki, S. Horita, M. Nangaku, and M. Suzuki

Abstract

Purpose

Acid-base transport in renal proximal tubules (PTs) is mainly sodium-dependent and conducted in coordination by the apical Na+/H+ exchanger (NHE3), vacuolar H+-adenosine triphosphatase (V-ATPase), and the basolateral Na+/HCO3 - cotransporter. V-ATPase on PTs is well-known to play an important role in proton excretion. Recently we reported a stimulatory effect of insulin on these transporters. However, it is unclear whether insulin is involved in acid-base balance in PTs. Thus, we assessed the role of insulin in acid-base balance in PTs.

Methods

V-ATPase activity was evaluated using freshly isolated PTs obtained from mice, and specific inhibitors were then used to assess the signaling pathways involved in the observed effects.

Results

V-ATPase activity in PTs was markedly enhanced by insulin, and its activation was completely inhibited by bafilomycin (a V-ATPase-specific inhibitor), Akt inhibitor VIII, and PP242 (an mTORC1/2 inhibitor), but not by rapamycin (an mTORC1 inhibitor). V-ATPase activity was stimulated by 1 nm insulin by approximately 20% above baseline, which was completely suppressed by Akt1/2 inhibitor VIII. PP242 completely suppressed the insulin-mediated V-ATPase stimulation in mouse PTs, whereas rapamycin failed to influence the effect of insulin. Insulin-induced Akt phosphorylation in the mouse renal cortex was completely suppressed by Akt1/2 inhibitor VIII and PP242, but not by rapamycin.

Conclusion

Our results indicate that stimulation of V-ATPase activity by insulin in PTs is mediated via the Akt2/mTORC2 pathway. These results reveal the mechanism underlying the complex signaling in PT acid-base balance, providing treatment targets for renal disease.

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Journal of Radioanalytical and Nuclear Chemistry
Authors: T. Sakashita, T. Hama, S. Fuma, M. Doi, Y. Nakamura, N. Ishii, and H. Takeda

Abstract  

To investigate the possibility of 14CO2 fixation using microorganisms in a high-dose area, the photosynthetic activity (specific production rate: SPR) and cellular proliferation (colony forming unit: CFU) of Euglena gracilis Z irradiated with gamma-rays at a dose of 0 to 500 Gy were determined. The dose responses of SPR and CFU suggested that it was possible to operate a CO2 fixation system of Euglena up to 100 Gy. Even at a dose of 500 Gy, about half of the photosynthetic activity under non-irradiated condition was considered possible.

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Abstract  

Uranium concentration and the 234U/238U activity ratio have been measured for the Tatsunokuchi hot spring waters of Ishikawa Prefecture in Japan, collected periodically over a long period (1977-2000). The concentration of 238U varied drastically between 0.045 and 1.02 mBq/l (a factor of about 20), while the 234U concentration was almost unchanged, ranging from 2.30 to 3.07 mBq/l. Resultant 234U/238U activity ratios showed a wide range from 2.7 to 51. Equilibrium calculation by using the geochemical code showed that U for one end-member representing low uranium contents and very high 234U/238U ratios was expected to exist as UO2(CO3)2 2-. By using the U isotopic and 14C dating methods, the age of this water was roughly estimated to be in the range of 104-105 years.

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Journal of Radioanalytical and Nuclear Chemistry
Authors: T. Nakamura, S. Kojima, T. Ohta, M. Nishida, A. Rakowski, A. Ikeda, H. Oda, and E. Niu

Abstract  

14C variations of atmospheric CO2 as well as carbonaceous fraction of living materials, such as collagen from tooth and bone, tissue, skin, hair, nail, etc., of modern humans are influenced by 14C produced artificially by nuclear bomb tests in the atmosphere from late 1950s to early 1960s. By careful investigation of 14C concentration of tree rings and human body samples formed in this time intervals, we can establish a relationship of their 14C concentrations with calendar year. By applying this relation to a sample whose 14C concentration can be measured, we can estimate the formation age of the sample. In addition, sources of the chemicals that were used in some criminal cases can be possibly identified, by their carbon isotope ratios (13C/12C and 14C/12C). This method of age determination has been applied to a forensic study, i.e., two criminal cases of murder. For each case, by comparing the measured 14C abundances of several pieces of hair and one tooth (the third molar) from the body with the annual change on concentrations of bomb-produced 14C, the time of death of the body and the age of the victim were estimated. The estimated values were consistent with the real ones that were revealed by the confession of the real murderers.

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