The separation of Am and Cm by using the tertiary pyridine resin embedded in silica beads was studied in nitric acid/methanol
mixed solvent system. This separation system of Am and Cm is very simple and easy. The adsorption and separation behaviors
of Am and Cm were investigated with changing the nitric acid and the methanol concentrations. It was confirmed that Am can
be almost completely separated from Cm.
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.
A positron lifetime study has been done on dielectric multilayer cavity mirrors for free-electron-laser experiments by the use of a variable-energy pulsed positron beam. A long-lived ortho-positronium component has been observed at low positron energy region, corresponding to the depth of the top amorphous SiO2 layer. The intensity of the positronium component correlates with the degradation and restoration of the mirrors. We discuss the relation between the positronium intensity and degradation mechanism of the mirrors. The present studies revealed that the slow positron lifetime technique is highly sensitive to the properties of the mirrors and is useful for the evaluation of the mirrors.
Excitation functions were measured by stacked-foil technique for the natZn(p,x)61Cu, 66Zn(p,x)61Cu, 68Zn(p,x)61Cu and natZn(p,x)60Cu nuclear processes up to 100 MeV. The experimental cross sections were compared with published data. On the base of these excitation functions, the cross sections of 64Zn(p,x)61Cu process were also deduced. Integral thick target yields were calculated for the 64Zn(p,x)61Cu and nat,64Zn(p,x)60Cu processes and irradiation parameters were elaborated for the 61Cu production via the 64Zn+p reactions for low and middle energy accelerators. According to our calculations the yield of 61Cu amounts to 1.02 . 1011 Bq . A-1 . s-1 (9.9 mCi .µ A-1 . h-1) from 19®10 MeV while it reaches 3.91 . 1011 Bq . A-1 . s-1 (38 mCi . µ A-1 . h-1) in the energy range of 67®60 MeV.
Elastic and glassy polymers are normally considered as homogeneous disordered materials with unimodal (statistical) distribution
of elementary free volumes. In this work, we discuss the results of our positron annihilation lifetime (PAL) measurements
for a number of elastic and glassy polymers, where observations of the two long-lived ortho-positronium components in the
PAL spectra and irregular (nonlinear) variations of annihilation characteristics in the vicinity of glass transition temperature
reveal structural heterogeneity of these systems. The conclusion is confirmed by measurements of thermo-stimulated luminescence,
thermo-mechanics and mobility of penetrants.
Distribution images of natural radioactivity in natural materials such as vegetables were obtained by using Imaging Plate. In such cases, it is necessary to reduce background radiation intensity by one order or more. Graded shielding is very important. Especially, the innermost surface of a shielding box should be covered with acrylic resin plate. We obtained natural radioactivity distribution images of vegetables, sea food, meat etc. Mostly -rays emitted from40K print the radioactivity distribution image. Comparison between -ray intensity of KCl solution measured with HPGe detector and that of natural material specimen gave the radioactivity around 0.060.4 Bq/g depending on the kind and the part of specimens.
A certified reference material designed for the determination of 129I in seawater, IAEA-418 (Mediterranean Sea water) is described and the results of certification are presented. The median
of 129I concentration with 95% confidence interval was chosen as the most reliable estimates of the true value. The median, given
as the certified value, is 2.28 × 108 atom L−1 (95% confidence interval is (2.16–2.73) 108 atom L−1), or 3.19 × 10−7 Bq L−1 (95% confidence interval is (3.02–3.82) × 10−7 Bq L−1). The material is intended to be used for standardization procedures applied in accelerator mass spectrometric laboratories.
It is available in 1 L units and may be ordered via IAEA web side (www.iaea.org).