Summary The simultaneous permeation of Sc, Y, Ce, Pm, Eu, Gd, Yb and Lu through a 2-ethylhexyl phosphonic acid-2-ethylhexyl ester (EHEHPA)-decalin membrane supported on a microporous polytetrafluoroethylene sheet was studied using a multitracer. The permeation rates of the elements from feed solutions of various acidity into receiving solutions of 2mol dm-3 HCl were determined. The feed solution at pH 1.5 gave the highest percentage of permeation for Ce, Pm, Eu, Gd and Yb, amounting to about 90 after -25h permeation. The percentage of permeation of Y and Lu was the highest at pH 1, amounting to about 90 after -25h permeation. The permeation of Sc from all the feed solutions was less than 4 due to its adsorption on the vessel. The permeation from the feed solution at pH 1.5 into the receiving solutions of 1, 2, 3, 4 and 5mol dm-3 HCl showed that the maximum percentage of transport for Y and Yb was obtained in 2mol dm-3 HCl receiving solution and that for Lu in 2-4mol dm-3 HCl receiving solutions. The other elements gave a percentage of transport more than 90 in 1-5mol dm-3 HCl receiving solutions, showing no obvious HCl concentration effect. The permeability coefficients of these elements were determined. Solvent extraction of the elements by EHEHPA-decalin was also carried out for comparison.

The ability of rice plants inoculated with Pyricularia oryzae (P. oryzae) to take up trace elements was studied by the radioactive multitracer technique. Among various elements, only Mn, Co, Zn, Se, Rb, Sr, Tc, and Re were found to be transferred to rice shoots from soil. The concentrations of essential elements, Mn and Zn, in the shoots of rice plants inoculated with P. oryzae were slightly higher than those in the control plant shoots, while Se, Rb, Tc, and Re showed almost the same concentrations for both the shoots.

Summary Irrespective of low bioavailability, some plant species accumulate Y and rare earth elements (REEs) to a great extent (accumulator species). The uptake mechanisms of Y and REEs were investigated for autumn fern, one of accumulator species. For comparison, plant species which accumulated poorly REEs (non-accumulator species) were also studied. In the present investigation, two noticeable phenomena were observed. (I) Autumn fern showed no ionic-radius dependence of Y-REE uptake by leaves, while non-accumulator species showed an extremely high uptake for Y compared with REEs. (II) Y-REE uptake by autumn fern was influenced by the addition of chelating reagents to the uptake solution, while no effect was observed for non-accumulator species.

The iron atoms in the SWNTs soot produced from a carbon rod with Fe-Ni metal by the arc-discharge method were studied for their chemical species by Mossbauer spectroscopy. They were found present as a mixture of some Fe-Ni alloys and the alpha-Fe metal particles of sizes more than 10nm that were dispersed. No change was observed in the Mossbauer spectra by the treatment of the soot with 1M HCl but a drastic temperature dependence of the spectra observed for the samples burned in air indicated that more than 50% of the iron was oxidized to Fe2O3 in small particles of less than 10nm. Effects of acid leaching and baking commonly used for separation of SWNTs were quantitatively studied by use of a radiotracer. Effectiveness of various kinds of metal atoms for forming nanonetwork materials were also investigated by taking advantage of the use of multi-radiotracers. A clear dependence of the yield of metal-containing fullerene species on the boiling point of the metal was indicated, and the yields were found sensitively affected by the amount of the current at the time of dc arc-discharge for the metal elements that were known to take +2 oxidation state in M@C-82.

With the aim of preparing carrier-free 28Mg and 47Ca simultaneously, Ti, V and Fe targets were examined by irradiating with high-energy ions of 12C, 14N and 16O accelerated by the RIKEN Ring Cyclotron. Among the targets, V gave the highest cross section for the formation of both 28Mg and 47Ca irrespective of the kind of beams. The cross section for the formation of 28Mg by the reactions of Ti, V and Fe targets with ion beams increased in the order of 12C < 16O<14N. On the other hand, the three beams exhibited almost the same cross sections for the formation of 47Ca by the reaction of a given target. Titanium and V were selected as prospective targets and 14N as a suitable beam for the production of 28Mg and 47Ca. Chemical separation procedures of the radiotracers in carrier- and salt-free states have been established by using cation exchange resins. The recovery yields of 28Mg and 47Ca from Ti target were 70 and 90%, respectively, and the decontamination factor was less than 10-5. The recovery yields of 28Mg and 47Ca from V target were 80% and the decontamination factor was less than 10-7.

Using a multitracer technique, the effects of acid rain pH on the adsorption of 15 trace elements on soil were studied. Kaolin, forest soil (original and with partially removed oxides), black soil (original and without organic matter)and Kureha soil (original, with partially removed oxides, and without organic matter) were employed as the adsorbents. Instead of H2SO4 solution, HCl solution was selected as the model acid rain based on the results of adsorption experiments on kaolin. In general, the percentage adsorption of cationic elements on three original soils and kaolin increased with increasing pH. The adsorption of oxyanionic elements, As and Se, on three soils was high over the entire pH range studied, while that on kaolin was low and decreased with an increase in pH. The differences in the physical and chemical properties of soils were reflected on the adsorption. The organicmatter in soil had positive effects on the extent of adsorption of most elements studied, while the oxides apparently showed positive effects only for Fe and Se adsorption. The results indicate that acid rain decreases the retention of cations in soil and that it increases or does not change the adsorption of anions.

: Cross sections for the production of target fragments in the reactions of iron with 135 MeV/nucleon 12 C and 80 MeV/nucleon 16 O ions have been measured by off-line γ-ray spectroscopy. Through these data, the mass yield distributions have been obtained. The result of the experiment for the reaction with 135 MeV/nucleon 12 C ions is compared with theoretical calculations using the fusion-fragmentation model and the GEMINI code for sequential binary decay, following a calculation with the fireball model.

This paper presents a study on the pH dependence of the adsorption of various elements, especially of lanthanides on solid-phase hematite (alpha -Fe(2)O(3)), in the presence and absence of humic add. For a precise evaluation of the adsorption behavior, simultaneous determination of the adsorption of Rb, ha, Pt, Eu, Gd, Tb, Tm, Yb, and Lu was conducted by the multitracer technique. The adsorption behavior of Eu onto Fe(3)O(4) and alpha -Al(2)O(3) was also studied, using a single tracer so that the effect of texture of the solid phase could be understood. From the present investigation, the adsorption behavior of Rb and Pa was found to be slightly influenced by the existence of humic acid. The pH dependence of the adsorption of lanthanides in the presence of humic add differed from that in the absence of humic add and was similar to the adsorption of humic acid on hematite, suggesting the adsorption of lanthanide-humate complexes.,The texture of the minerals showed a small effect on the distribution of humic acid and the humic acid-Eu complex.

The effects of soil acidity on the uptake of trace elements (Co, Zn, Se, Rb, Sr, Y, Zr, Tc, Ru, Rh and Re) in soybean and tomato were studied by a multitracer technique. The soybean and tomato plants were cultivated on soils at pH 6.4 (normal soil) and 4.2 (acid soil) and administered with a multitracer for 15–60 d. In general, the uptake of cationic elements in the leaves and stems of soybean plants cultivated on acid soil became higher than those of plants cultivated on normal soil during the late period of growth. However, the effect of soil acidification on the uptake of the anionic element, Se, was quite different from that on the cationic elements. The uptake of Se by the plants cultivated on normal soil was higher than that of the plants cultivated on acid soil at all four harvest points. The uptake behavior of these elements in soybean was discussed in relation to their adsorption behavior on the same soil as was used for soybean cultivation. The growth of tomato plants was seriously affected by the soil acidity and lowering of uptake of elements was observed for the plants cultivated on acidified soil.

The subcellular distribution of radionuclides in Glycine max Merr. (soybean) and Cucumis sativus L. (cucumber) and translocation of plant absorbed radionuclides with growth in soybean were studied. More than 60% of cellular incorporated Rb, Sr, Mn, Co, Nb, and Se remained in the supernatant fraction; 55% and 20% of Cr was bound to soybean and cucumber cell wall fractions, respectively; 70% or more of Be, Y, and Fe was fixed in the chloroplast fraction; and approx. 10% of Sc, Fe, V, and As were fixed in the mitochondrial fraction. Translocation of nuclides within the soybean plant at different stages of growth has been determined. Vanadium, Y, Be, Se, Nb, Sc, Cr, and Zr were predominantly accumulated in the root. Although the total percentage of plant uptake of Sc, Zr, Nb, and Cr was high, because of low mobility and translocation to shoot, their accumulation in the fruit fraction was negligible. The translocation of mobile nuclides in plants was demonstrated clearly by Rb, Zn, and Fe. Data on the nuclide fraction mobilized from vegetative parts into edible parts was used to assess the percentage of accumulated radionuclides in plants that may reach humans through beans.

The uptake and distribution of radioisotopes of beryllium, calcium, scandium, vanadium, chromium, manganese, iron, cobalt, nickel, zinc, gallium, arsenic, strontium and barium in vitamin D (VD)-overloaded rats were investigated and compared with those in control rats, using the multitracer technique. Each element revealed its characteristic distribution among various organs in control and VD-overloaded rats. For some elements, such as cobalt and chromium, the distribution patterns in them were significantly different. These results are discussed in terms of the metabolism of the elements in rats.

The mobility of 46Sc, 54Mn, 58Co, 74As, 75Se, 83Rb, 85Sr, 88Y, 149Eu, 146Gd, 169Yb, 175Hf, 183Re, and 192Ir in soybean plants after foliar deposition was determined by a multitracer experiment. The plants were grown in a controlled area under no-rain conditions for different periods. They were exposed to multitracer-absorbed cellulose powder, and the radionuclide content in the seeds, pods, corpus, tunica, and roots was determined after they were harvested. Rubidium showed the highest mobility in the plant among those radionuclides followed by Se and Co which were classified as `mobile'. Mn, As, Sr, and Re form a second class of `medium mobility'. The contents of 46Sc, 88Y, 149Eu, 146Gd, 169Yb, 175Hf, and 192Ir were below the detection limit in the seeds; these elements are classified as `immobile'. The data obtained in this experiment cannot directly be converted into translocation factors applied in radioecological models, but they allow to check the classification used presently in such a model for elements on which little or no information is available at present.

The binding affinity of various trace elements to blood components and the pH-dependence of the binding affinity of the elements to serum proteins were examined using the radioactive multitracer technique. The binding affinity of 13 elements (Be, V, Mn, Zn, Se, Rb, Sr, Ce, Eu, Gd, Tm, Yb, and Lu) was simultaneously determined by gamma-ray spectrometry. The blood drawn from rats was separated into plasma, corpuscles, and erythrocyte ghosts. It was found that Be, Sr, Mn, and Zn bind highly to the plasma proteins. V and Se were highly bound to the corpuscles, and Se to the erythrocyte ghosts as well. Similar binding percentages of rare earth elements (Ce, Eu, Gd, Tm, Yb, and Lu) were found for each of the blood components, with the highest percentages being observed for plasma proteins. Albumin, beta-globulin, gamma-globulin, apotransferrin, and holotransferrin were examined in the study on the affinity of individual serum proteins. The pH dependence of the affinity of metal ions to the serum proteins in the pH range of 6.4-8.5 was examined using ultrafiltration and gamma-ray spectrometry. Each element showed a characteristic binding affinity to each serum protein, depending on pH. The results are discussed in terms of the chelating ability of metal ions and the nature of the serum proteins.

The formation of metallofullerenes was examined for 23 elements, and some experimental evidence was obtained for metallofullerenes with group-4, Zr and Hf, and group-5, Nb, elements. Relative yields of the metallofullerenes eluted at the retention time around those for M@C82 (M=group-2 and -3 elements) were found to decrease exponentially as the group number increased. The yields for Fe and Co, namely group-8 and -9 elements, were estimated to be less than one hundredth of that for M@C82 (M=lanthanoid)

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.

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.

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.

The uptake and translocation of trace elements in maturing soybean plants cultivated on soil were studied over 360 h under diurnal conditions after the administration of a multitracer. The contents (%/g) of Co, Se, Rb, Sr, Ru, Rh, and Cs in all the leaves and stems collected from each node increased up to around 200 h after the administration of the multitracer and then decreased with time. The contents of Zn, Tc, and Re in the leaves and Zn in the stems continuously increased up to 360 h, but Tc and Re in the stems showed maximum content. This observation suggests the translocation of these elements from old leaves to growing leaves via stems. The relationship between the content (%/g) of an element in the seeds and pods, and the cultivation time varied depending on the kind of element and on the growth steps. Mathematical analyses were applied to the behavior of the elements in the soybean. The time dependence of the uptake rate (%/g/h) and distribution of elements in each part of the plant were characteristic of the element.