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  • Author or Editor: S. Ambe x
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Abstract  

The influence of Al on the absorption of various elements by a carrot (U.S. harumakigosun) was investigated using a multitracer technique. An uptake experiment was conducted within the range of 0.0–2.0 ppm AlCl3 in culture solution. By the addition of AlCl3, uptake of elements such as Be, V, Zn and rare earth elements (REE) into roots was increased. For Be and V an approximately three-fold increase was observed. The degree of uptake enhancement of nonessential elements by AlCl3 was generally very high, whereas some of the essential or beneficial elements exhibited a decrease in uptake with the increase of AlCl3 concentration. This suggests that the uptake of nonessential elements might be increased through transporters with decreased selectivity due to Al. From the viewpoint of the acid rain problem, it is suggested that one of the detrimental effects of Al on plants is the imbalanced elemental absorption.

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Abstract  

The uptake and the distribution of radioactive trace elements in Se-deficient rats were examined by the multitracer technique, which can be used to evaluate the behavior of many elements under the same experimental conditions. The uptake of Se was larger in the brain, spleen, and testicles of the Se-deficient rats than in those of the normal ones. The uptake of As, Fe, and Sc was larger in the liver of Se-deficient rats than in that of normal ones. In the bone, the uptake of Zr of Se-deficient rats was larger than that of normal ones. Selenium is known to be in a competitive or synergetic relationship with several metals. From the present results on Sc and Zr, it was newly cleared up that there is also some interaction between those elements and Se.

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Abstract  

Separation of Au(III) and various carrier-free radionuclides by solvent extraction was investigated using an Au target irradiated by an energetic heavy-ion beam. Percentage extraction of Au(III) and coextraction of the radionuclides were determined with varying parameters such as kinds of solvent, molarity of HCl or pH, and Au concentration. Under the conditions where Au(III) was effectively extracted, namely extraction with ethyl acetate or isobutyl methyl ketone from 3 mol·dm–3 HCl, carrier-free radionuclides of many elements were found to be more or less coextracted. Coextraction of radionuclides of some elements was found to increase with an increase in the concentration of Au(III). This finding is ascribed to the formation of strong association of the complex of these elements with chloroauric acid. In order to avoid serious loss of these elements by the extraction, lowering of the Au(III) concentration or the use of a masking agent such as sodium citrate is necessary. Gold(III) was shown to be effectively back extracted with a 0.1 mol·dm–3 aqueous solution of 2-amino-2-hydroxymethyl-1,3-propanediol. Thus, a radiochemical procedure has been established for preparing a carrier-free multitracer and an Au tracer with carrier form from an Au target irradiated with a heavy-ion beam. Both tracers are now used individually for chemical and biological experiments.

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Abstract  

The multitracer technique was applied to the simultaneous evaluation of the behavior of a large number of radioactive nuclides. The binding affinity of various trace elements with blood components and the pH-dependence of binding affinity of the elements with serum proteins were examined using the multitracer technique. Each element showed characteristic binding to each blood component and serum protein. The results are discussed in terms of chelating ability of metal ions and the nature of the serum proteins.

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Abstract  

The solvent extraction of Zr and Hf was studied using 444-trifluoro-1-(2-thienyl)-1,3-butanedione (TTA) from a multitracer solution containing carrier-free radioisotopes of Zr, Hf, and other elements. The multitracer was prepared from Au foil irradiated with high-energy heavy-ion beams. Effects of HCl and HNO3 concentrations and organic solvent on the extraction and coextraction of other radionuclides have been studied. It was found that decalin (decahydronaphthalene) was the best solvent among 14 solvents studied and the optimum aqueous phase was 2 mol·dm–3 HCl or HNO3. About 2–10% of Sr, Rb, Sc and Nb were coextracted with Zr and Hf. The reversed phase extraction of Zr and Hf was also developed by using ethylenediaminetetraacetic acid (EDTA) solution at pH range of 8.5–10.

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Abstract  

About 70 kinds of fem samples have been analyzed by means of neutron activation analysis in order to deduce characteristics and mechanisms of accumulation of rare earth elements. Accumulator species for scandium and lanthanides have been newly found based on the analysis. Correlations among barium, hafnium, and lanthanides indicate that the fems accumulating barium and hafnium also showed high concentrations of lanthanides. Remarkable accumulation of lanthanides in diversifying genera suggests that lanthanides contribute to making those species diverse.

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Abstract  

The effect of ZnCl2 on the uptake of Be, Na, Mn, Co, Zn, Se, Rb, Sr, Rh, Cs and lanthanoids (Ce, Pm, Gd and Lu) by carrot (Daucas carota cv. U.S. harumakigosun) was investigated. Uptake was measured using a multitracer technique which enables to acquire information about various elements under identical conditions. The amount of uptake of Rb, Cs, Sr, Mn and Co, into roots decreased with increasing concentration of ZnCl2. On the other hand, little effect was observed for the uptake of Be, Se, Rh and lanthanoids. These results suggest that Rb, Cs, Sr, Mn and Co competed antagonistically with Zn for the binding sites of carriers in the roots, while there was no influence on the uptake of the other elements. Uptake of Se was not influenced by Cl added as ZnCl2. It is concluded, therefore, that carrot can distinguish Se from Cl based on the physicochemical differences between these two anion species.

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Abstract  

The radioactive multitracer technique was applied to a study on the uptake of trace elements in normal C57BL/6N mice. Comparative uptake behavior of46Sc,54Mn,59Fe,58Co,65Se,83Rb and88Zr tracers was examined among 11 organs (brain, cardiac muscle, lung, liver, spleen, pancreas, kidneys, bone, muscle, eyeballs and testes) and blood, and evaluated in terms of the “tissue uptake rate (the radioactivity percentage of injected dose per gram of tissue, %dose/g)”. The multitracer technique revealed reliable data demonstrating characteristic uptake of the 8 trace elements, Sc, Mn, Fe, Co, Zn, Se, Rb and Zr by the brain and other organs, as well as the distinctive features of the accumulation and retention of each element in the brain.

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