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Summary  

Major and trace elements in soil and plant samples, including standard reference materials were determined by means of neutron activation analysis (NAA) and inductively coupled plasma-mass spectrometry (ICP-MS). The analytical procedure for NAA utilized dried powder samples. The concentration of iodine in soil samples was determined by radiochemical NAA. The irradiated samples were cooled and then counted with a Ge gamma-ray detector connected to a multi-channel analyzer. For ICP-MS analysis, the samples were decomposed by microwave digestion with an acid mixture. The concentration of I in the soil samples was measured by ICP-MS after separation by ignition. The analytical values for most elements in the environmental samples by both methods were in good agreement, whereas sample treatments were different. Measured value of Zr in the soil samples by ICP-MS was about 50% lower than that by NAA. It should be assumed that some minerals of Zr in soil particles were not entirely dissolved by the acid mixture. Analytical results of Cd for three different Cd levels in unpolished rice flour samples (NIES 10-a, b and c) determined by ICP-MS were in agreement with certified values. The concentration of Cd in the sample with the lowest Cd level, as determined by NAA with 57% counting error, was 3 times higher than the certified value.

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Journal of Radioanalytical and Nuclear Chemistry
Authors:
S. Mitsuoka
,
H. Ikezoe
,
T. Ikuta
,
S. Hamada
,
Y. Nagame
,
K. Tsukada
,
I. Nishinaka
, and
T. Ohtsuki

Abstract  

In order to separate rare fusion evaporation residues from the primary beam in flight, a recoil mass separator has been constructed at the JAERI tandem-booster facility. By using the recoil mass separator, new neutron-deficient isotopes209Th and212Pa have been produced. After a brief facility description, some recent experimental results are presented.

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Journal of Radioanalytical and Nuclear Chemistry
Authors:
J. Glatz
,
I. Garcia-Alonso
,
T. Kameyama
,
L. Koch
,
G. Pagliosa
,
T. Tsukada
, and
H. Yokoyama

Abstract  

In order to study the dissolution behavior of a highly burnt LWR fuel, a fuel pin irradiated in the DR3 test reactor in Risoe National Laboratory, has been characterized by microstructural examination and then dissolved under PUREX type conditions. The dissolution behavior was investigated and the residues analyzed by scanning electron microscopy and by ICP-MS and IDMS after dissolution.

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Abstract  

Anion-exchange behavior of the group-5 elements, Nb and Ta, and their pseudo homologue Pa in HF and HF/HNO3 solutions was investigated by a batch method to find suitable conditions for the anion-exchange experiment of element 105 (Dubnium, Db). We determined the distribution coefficients of those elements on the anion-exchange resin as a function of the F and NO3 concentrations. Clearly different anion-exchange behavior was observed among these elements. Based on the results, we discuss the fluoro-complex formation of each element and suggest experimental conditions for the study of fluoride complexation of Db.

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Abstract  

An isothermal chromatographic apparatus was developed for the on-line experiments of super heavy elements in gas phase. As a model of Rf, we investigated the gas phase chemistry of Zr and Hf chlorides. The dependence of the reaction efficiency on temperature was examined. It was found that about 80% of Zr and Hf reacted with chlorinating gas at 900 °C. Adsorption enthalpies of Zr and Hf chlorides were deduced from the isothermal chromatograph by the Monte Carlo simulation based on the microscopic model proposed by Zvára.

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Abstract  

Adsorption of carrier-free radiotracers 181W and 93mMo produced in the 181Ta(p, n) and natNb(p, n) reactions, respectively, on anion-exchange resin was studied in mixed solution of HF and HNO3 in a concentration range of 10−4–10−1 M HF/0.1 M HNO3. Distribution coefficients (K d) of 181W and 93mMo at 70 °C showed the V-shaped variation with the minimum at around 10−1 M HF/0.1 M HNO3, although variation of the K d values for 93mMo was quite small compared with that for 181W. Formation of oxofluoro complexes for W and Mo is briefly discussed.

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Journal of Radioanalytical and Nuclear Chemistry
Authors:
T. Maruyama
,
D. Kaji
,
T. Kaneko
,
S. Goto
,
K. Tsukada
,
H. Haba
,
M. Asai
,
S. Ichikawa
,
Y. Nagame
, and
H. Kudo

Abstract  

Rapid chemical separation of berkelium is essential in order to measure the unknown isotope 252Bk. An anion exchange system of mineral acid and methanol was examined. An elution curve of Bk was obtained using 250Bk produced by the 248Cm+18O system and the 251Bk activity could be measured in the preliminary experiments. The whole chemical separation was completed within 30 minutes.

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Journal of Radioanalytical and Nuclear Chemistry
Authors:
K. Akiyama
,
K. Sueki
,
H. Haba
,
K. Tsukada
,
M. Asai
,
T. Yaita
,
Y. Nagame
,
K. Kikuchi
,
M. Katada
, and
H. Nakahara

Abstract  

We have, previously, reported on the HPLC elution behavior of the Th, Pa, U, Np, and Am metallofullerenes and the UV/vis/NIR absorption spectra of the Th@C84 and U@C82 species. In this paper, the followings are reported: (1) Pu metallofullerenes were produced and their HPLC elution behavior was investigated using a radiotracer technique. The HPLC chromatogram of this metallofullerene was found to be almost the same as that of the Np and Am metallofullerenes. (2) The oxidation states of Th@C84 and U@C82 produced in macroscopic quantities were examined by XANES (X-ray absorption near edge structure) measurements. The oxidation state of the U atom in the C82 fullerene cage was estimated to be 3+ with the formal charge of the ionic molecule being U3+@C82 3-.

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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. Sekine
,
S. Ichikawa
,
A. Osa
,
M. Koizumi
,
H. Iimura
,
K. Tsukada
,
I. Nishinaka
,
Y. Hatsukawa
,
Y. Nagame
,
M. Asai
,
Y. Kojima
,
T. Hirose
,
M. Shibata
,
H. Yamamoto
, and
K. Kawade

Abstract  

Studies on the decay of unstable nuclei using the two on-line isotope separators of JAERI are reviewed for the past five years. With the previously established ion-source technique using mono-oxide ion formation in a thermal ion source, the new nuclides125Pr and127Pr have been identified in heavy-ion fusion residues. Further, with a newly developed gas-jet coupled thermal ion source, the new nuclides166Tb,165Gd,161Sm and236Am have been identified by bombarding238U and235U targets with a proton or6Li beam. Other studies, including off-line experiments, by decay spectroscopy, laser spectroscopy and Mössbauer spectroscopy are described.

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