Authors:K. Hayashi, T. Mori, M. Yanaga, I. Satoh, and H. Suganuma
The stability constants (β1) of iodide ion-pairs of trivalent f-block element ions (lanthanoids Ce, Eu, Gd, Tb and Tm, and actinoid Am) were determined
in the vicinity of pH 2.5 of mixed methanol/water solvent solutions of an ionic strength of 1.00 mol·dm−3 at 298±1 K. The values were less than 2. From the variation in distance between Eu3+ and I−, which was calculated using a Born-type equation for Gibbs’ free energy derived from β1(Eu), the Eu3+-I− interaction was shown to be solvent-shared ion-pair formation when the mole fraction of methanol (XMeOH)≤0.40. In contrast, it was suggested that the interaction of Am3+-I− changed from solvent-separated ion-pair to solvent-shared ion-pair with increasing XMeOH when XMeOH≤0.10, but remained as solvent-shared ion-pair in the range 0.16≤XMeOH≤0.40. Furthermore, β2(Am) was measured in the range 0.31≤XMeOH≤0.40. It was also shown that the β1 values of lanthanoids at XMeOH = 0.40, except for that of Gd(III), decreased with increasing atomic number.
Authors:H. Satake, M. Aoyama, T. Kawada, T. Sekiguchi, T. Sakai, M. Fujie, and Nori Satoh
Ci-TK and Ci-TK-R are authentic tachykinin (TK) and TK receptor isolated from a protochordate,
. In this study, we investigated a novel function of TK as an enhancer of oocyte growth. Ci-TK-R is expressed specifically in the
vitellogenic oocytes. Moreover, administration of Ci-TK to the
ovary resulted in upregulation of gene expression and enzymatic activity of several proteases. Moreover, maturation of the
oocytes from the vitellogenic stage to the post-vitellogenic stage was induced in the presence of Ci-TK, which was completely blocked by addition of protease inhibitors.
Authors:M. Yagi, Y. Shiokawa, S. Suzuki, M. Hara, I. Satoh, K. Masumoto, and T. Mitsugashira
Neutron emission from the d-d nuclear fusion reaction, D/d,n/3He, in and on titanium metals /titanium sponge and the mixture of titanium powder/ trapped deuterium at about 1 atm has been ascertained by using a high resolution liquid scintillation detector. The neutron emissions from 11 samples which were provided under wide varieties of conditions were measured by temperature change in the range of liquid nitrogen temperature to 350 °C. As a result, it was proved that the neutron emission observed can be divided into two types, such as cooling and heating, by the evolved conditions. Moreover, by estimating the neutron emission efficiencies of samples, it was suggested that the neutron emission reactions are closely related to the deuterium trapped in the surface of titanium metal.
Authors:M. Yagi, T. Mitsugashira, I. Satoh, M. Hara, Y. Shiokawa, K. Inoue, K. Masumoto, and S. Suzuki
As a new fact, the neutron emission from the d-d nuclear fusion reaction in a SiO2–D2 system has been confirmed as well as that in the Ti–D2 system. By using a liquid scintillation detector, the neutron emissions from 8 sample materials consisted of SiO2, in which a small amount of deuterium was adsorbed chemically on the surface layer, were measured in the range of temperature between liquid nitrogen temperature and 400 °C. As a result, it was demonstrated that the neutron-emission reactions take place predominantly on the surface layer of sample material.
Authors:T. Nakanishi, M. Satoh, M. Takei, A. Ishikawa, M. Murata, M. Dairyoh, and S. Higuchi
Plutonium 239,240 was measured using large-volume water samples from the North Pacific and its adjacent seas. The vertical profiles of239,240Pu show features that are similar to those reported in earlier papers with a subsurface maxima of around 660 m and a significant concentration increase in the North Pacific bottom waters. It became evident that the239,240Pu concentration in deep bottom water is proportional to the inventory of the nuclides in the overlying water column and that the appearent distribution ratios of the nuclides between deep-sea sediment and bottom water lie in a relatively narrow range of about 2×104 to 105, independent of sea area and warter depth. The latter implies that239,240Pu may follow a reversible-type partition process at a deep water/sediment interface. In order to substantiate this assumption, it is desirable to study the phenomenon for Pu as well as for other long-lived radionuclides, both artificial and natural. From this point of view, an analytical procedure for the successive determination of selected long-lived radionuclides was studied.
Authors:T. Nozaki, A. Satoh, H. Muraoka, J. Ishiguro, K. Yoda, and K. Ogawa
Aerosol particles of99mTc-labeled carbon were prepared by sublimation and introduced in various liquid media. The adsorption of the aquasol and organosol
particles were studied for various adsorbing substances and media, with the effect of surface treatment and voltage application.
The particles often accumulated at the aqueous-organic interface, and also on the vessel surface in the presence of both aqueous
and organic phases. The distribution of the particles was examined by a gamma-camera for different organic phases under various
concentrations of electrolytes in the aqueous phase.
Authors:A. Miyake, A. Kimura, Y. Satoh, R. Shimizu, M. Inano, and T. Ogawa
In order to obtain a better
understanding of the thermal hazard of hydrazine and nitric acid mixtures
which are used in plutonium and uranium recovery by extraction (PUREX) process
during recycling of spent fuel in nuclear plant, DSC was carried out for the
mixed system made by the small scale reaction calorimeter super-CRC in various
conditions. It was found that the concentration of the nitric acid has a strong
influence on the thermal behavior of the mixed system, and hydrazine nitrate
which is formed in the reaction in the mixture was determined by DSC with
Authors:M. Nakamura, N. Satoh, H. Tsukada, T. Mizuno, W. Fujii, A. Suzuki, S. Horita, M. Nangaku, and M. Suzuki
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.
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.
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.
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.