X-Ray Analysis Literatures 2012

2012年に出版されたX線分析に関連する文献および情報について，X線分析技術の発展に寄与し重要であると編集委員が選抜した文献を総説としてまとめた．調査対象はe-ジャーナル，webマガジンを含む学術誌18誌，制定された規格およびX線関連メーカーの新技術情報である．各雑誌について全体的な傾向および選抜したいくつかの論文に対して論評を記した．The selected literatures about advances in X-ray analysis and X-ray analysis-related information published in 2012 were reviewed on the basis of analytical chemistry, physics, techniques, optics, instrumentation and so forth. The 18 kinds of academic journals including web-magazines, Japanese Industrial Standard (JIS), and websites of companies related with X-ray tools and/or X-ray apparatus were researched. The trend of publications related to X-ray analysis for each journal was overviewed, and some of noticeable literatures were commented

Comparison of cadmium distribution in the root tissues of Solanum melongena and Solonum torvum, which have different abilities for cadmium transport from the root to shoot

Grafting the eggplant Solanum melongena onto Solanum torvum has been reported to be an effective method for reducing cadmium (Cd) concentration in the fruits of eggplant. Although Cd concentration in the roots of both species of eggplant was almost identical, it was observed to be higher in the shoot and xylem sap of S. melongena. We thus assumed that the translocation of Cd into the shoot of S. torvum was inhibited by a barrier function in its root tissues. Using synchrotron micro X-ray fluorescence (SR μ-XRF), we attempted to elucidate the role of root tissues in the inhibition of Cd transport to the shoot by comparing the microscale distribution pattern of Cd in the root tissues of S. melongena and S. torvum. Cd was localized in the central cylinder and epidermis in the transverse sections of S. melongena, regardless of the distance from the root apex. In the root section of S. torvum, the intensity of X-ray fluorescence from Cd, which was evenly distributed at 10 mm from the root apex, was very weak; in contrast, remarkable localization of Cd in the endodermis was observed in the root section at 40 mm. These contrasting distribution patterns of Cd explained the higher Cd concentration in the xylem sap of S. melongena than in the xylem sap of S. torvum. In conclusion, radial transport of Cd toward the central cylinder was restricted by an endodermal barrier—Casparian band or suberin lamella—present in the root of S. torvum. This barrier function of root tissue is one of the mechanisms responsible for low Cd loading to the xylem of S. torvum as compared to S. melongena

Metal distribution in rice seeds during the germination

To investigate the flow of the nutrients iron (Fe), zinc (Zn), manganese (Mn), and copper (Cu) during rice seed germination, we performed microarray analysis to examine the expression of genes involved in metal transport. Many kinds of metal transporter genes were strongly expressed and their expression levels changed during rice seed germination. Furthermore, imaging of the distribution of elements (Fe, Mn, Zn, and Cu) was carried out using Synchrotron-based X-ray microfluorescence at the Super Photon ring-8 GeV (SPring-8) facility. The change in the distribution of each element in the seeds following germination was observed by in vivo monitoring. Iron, Mn, Zn, and Cu accumulated in the endosperm and embryos of rice seeds, and their distribution changed during rice seed germination. The change in the patterns of mineral localization during germination was different among the elements observed

Silver speciation in liver of marine mammals by synchrotron X-ray absorption fine structure and X-ray fluorescence spectroscopies

Made available in DSpace on 2016-02-17T21:43:07Z (GMT). No. of bitstreams: 5 silver.pdf: 360517 bytes, checksum: 83770e7b2d638debab40d6dfcdcbad77 (MD5) license_url: 49 bytes, checksum: 4afdbb8c545fd630ea7db775da747b2f (MD5) license_text: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) license.txt: 120 bytes, checksum: c5ec8a89f6203da160ca192812b3f657 (MD5) Previous issue date: 2011The chemical form of Ag in the livers of five species of marine mammals was examined using X-ray absorption fine structure (XAFS) and X-ray fluorescence (XRF) spectroscopies. The XAFS analysis suggested that Ag(2)Se was present in the livers of the Franciscana dolphin (Pontoporia blainvillei), Dall's porpoise (Phocoenoides dalli), and Baird's beaked whale (Berardius bairdii), whereas Ag(2)S was present in the livers of the striped dolphin (Stenella coeruleoalba) and pygmy killer whale (Feresa attenuata). XRF spectroscopy results revealed that the distribution patterns of Ag and Se in a thin section of the liver of the Franciscana dolphin were the same; this also implied that Ag was associated with Se in the liver. Thus, the interaction of Ag with Se or S may offer significant protection against the toxicity of Ag in marine mammals. The formation of either Ag(2)Se or Ag(2)S might depend on the Hg levels in the liver. Ag(2)Se was observed in liver samples with relatively high Ag/Hg ratio, whereas liver samples with low Ag/Hg ratio contained Ag(2)S

Effects of Cadmium Treatment on the Uptake and Translocation of Sulfate in Arabidopsis thaliana

Cadmium (Cd) is a highly toxic and non-essential element for plants, whereas phytochelatins and glutathione are lowmolecular- weight sulfur compounds that function as chelators and play important roles in detoxification. Cadmium exposure is known to induce the expression of sulfurassimilating enzymes and sulfate uptake by roots. However, the molecular mechanism underlying Cd-induced changes remains largely unknown. Accordingly, we analyzed the effects of Cd treatment on the uptake and translocation of sulfate and accumulation of thiols in Arabidopsis thaliana. Both wild type (WT) and null mutant (sel1-10 and sel1-18) plants of the sulfate transporter SULTR1;2 exhibited growth inhibition when treated with CdCl2. However, the mutant plants exhibited a lower growth rate and lower Cd accumulation. Cadmium treatment also upregulated the transcription of SULTR1;2 and sulfate uptake activity in WT plants, but not in mutant plants. In addition, the sulfate, phytochelatin and total sulfur contents were preferentially accumulated in the shoots of both WT and mutant plants treated with CdCl2, and sulfur K-edge XANES spectra suggested that sulfate was the main compound responsible for the increased sulfur content in the shoots of CdCl2-treated plants. Our results demonstrate that Cd-induced sulfate uptake depends on SULTR1;2 activity, and that CdCl2 treatment greatly shifts the distribution of sulfate to shoots, increases the sulfate concentration of xylem sap and upregulates the expression of SULTRs involved in root-toshoot sulfate transport. Therefore, we conclude that root-toshoot sulfate transport is stimulated by Cd and suggest that the uptake and translocation of sulfate in CdCl2-treated plants are enhanced by demand-driven regulatory networks

Layered Na_<i>x</i>Cr_<i>x</i>Ti_1–<i>x</i>O₂ as Bifunctional Electrode Materials for Rechargeable Sodium Batteries

A binary system of NaCrO₂–TiO₂, Na_<i>x</i>Cr_<i>x</i>Ti_1–<i>x</i>O₂ (1.0 ≥ <i>x</i> ≥ 0.5), is systematically examined, and the electrodes’ performance is tested in Na cells. Different layered phases, O3, Na-deficient O3, P2, and P3, are found in this system, as confirmed by X-ray and neutron diffraction techniques. Among them, P2-type Na_2/3Cr_2/3Ti_1/3O₂ and P3-type Na_0.58Cr_0.58Ti_0.42O₂ show excellent electrode performance as positive and negative electrode materials, respectively. P2 Na_2/3Cr_2/3Ti_1/3O₂ shows excellent rate capability as a positive electrode, and average voltage based on Cr³⁺/Cr⁴⁺ redox in a Na cell is increased compared with that of O3-type NaCrO₂. The operating voltage of Cr³⁺/Cr⁴⁺ is also enhanced because of an inductive effect of Ti⁴⁺ substitution for Cr³⁺. However, the reversible range is limited to <i>x</i> < 1/3 in Na_{2/3–<i>x</i>}Cr_2/3Ti_1/3O₂ associated with partial Cr oxidation to Cr⁶⁺ and migration into tetrahedral sites upon charging, as found by X-ray diffraction and X-ray absorption spectroscopy. P3 Na_0.58Cr_0.58Ti_0.42O₂ delivers ∼110 mAh g^–1 of reversible capacity as a negative electrode with excellent capacity retention and rate capability. From these results, the possibility of Na_<i>x</i>Cr_<i>x</i>Ti_1–<i>x</i>O₂ as bifunctional electrode materials for rechargeable sodium batteries is also discussed