Search

Initial analyses showed that asteroid Ryugu's composition is close to CI (Ivuna-like) carbonaceous chondrites (CCs) - the chemically most primitive meteorites, characterized by near-solar abundances for most elements. However, some isotopic signatures (for example, Ti, Cr) overlap with other CC groups, so the details of the link between Ryugu and the CI chondrites are not yet fully clear. Here we show that Ryugu and CI chondrites have the same zinc and copper isotopic composition. As the various chondrite groups have very distinct Zn and Cu isotopic signatures, our results point at a common genetic heritage between Ryugu and CI chondrites, ruling out any affinity with other CC groups. Since Ryugu's pristine samples match the solar elemental composition for many elements, their Zn and Cu isotopic compositions likely represent the best estimates of the solar composition. Earth's mass-independent Zn isotopic composition is intermediate between Ryugu/CC and non-carbonaceous chondrites (NCs), suggesting a contribution of Ryugu-like material to Earth's budgets of Zn and other moderately volatile elements.

The Fukushima Daiichi Nuclear Power Plant (FDNPP) accident in March 2011 emitted a considerable amount of radioactive materials. This study isolated radiocesium-bearing microparticles (CsMPs), a form of radioactive materials emitted from the FDNPP at the early stage of the accident, from aerosols collected hourly on filter tapes at seven monitoring stations at the greater Kanto Region, including the Tokyo metropolitan area, on 15 March 2011. The aerosols had a spherical shape ~ 1 μm in diameter with activity of less than 1 Bq of 137Cs per particle. Their physical and chemical characteristics, including radioactivity ratio 134Cs/137Cs as well as chemical composition and state, are essentially the same as previously reported CsMPs. This study demonstrated that air parcels containing CsMPs emitted from the FDNPP were widespread over the greater Kanto Region, more than 250 km away from the FDNPP, during the daytime of 15 March. Trajectory analysis indicated that these particles were emitted from the reactor No. 2 of FDNPP between 14 March evening and 15 March early morning. The information obtained on the widespread distribution of CsMPs can be useful for assessing the actual impacts of radioactive contamination from the FDNPP accident on the environment and human health.

Blue-painted pottery was produced in the New Kingdom, Egypt, and decorated with blue, red, and black pigment. In this study, two newly developed portable instruments, a portable X-ray fluorescence spectrometer and a portable X-ray powder diffractometer, were brought to the site on the outcrop at Northwest Saqqara, an archaeological site in Egypt, to verify their performance in on-site analysis of excavated artifacts at the site. Pigments used for the blue-painted pottery and plasters in the New Kingdom were analyzed by these instruments on the basis of both their chemical compositions and crystal-structural information. The blue pigments were identified as two different pigments, Egyptian blue and cobalt blue. The diffraction pattern of the blue pigment of the painted pottery exhibited that of spinel structure. The XRF spectrum of the blue pigment obtained by the same instrument from the same position indicates the presence of Mn, Co, Fe, Ni, and Zn. The possibility of compositional transitions of the cobalt blue pigment with time was revealed on by detailed analysis of the XRF data. The reason for the transitions is considered together with the archaeological background of the New Kingdom, Egypt.

To investigate the flow of the metal 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. We found that metal transporter genes such as ZIP family has tendency to decrease in their expressions during 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.

Total reflection X-ray fluorescence spectrometry (TXRF) has been applied for trace elemental analysis of small glass fragments. A small glass sample (a fragment with weight less than 0.5 mg) was decomposed by 100 microg of HF/HNO3 acid; the material was condensed to 10 microl and was dried on a Si wafer. Since the size of the dried residue on the Si wafer was less than 1 cm in diameter, an incident X-ray beam with about 1 cm in width could effectively excite elemental components in such a small glass fragment. The precision of the present technique was checked by analyzing the glass fragments (0.5 mg) from NIST SRM612; the relative standard deviations (RSD) of less than 8.1% were achieved for elemental ratios that were normalized by Sr. Fragments (0.5 mg) obtained from 23 figured sheet glasses were used as samples for estimating the utility of this technique to forensic discrimination. Comparison of five elemental ratios of Ti/Sr, Mn/Sr, Zn/Sr, Rb/Sr, and Pb/Sr calculated from X-ray fluorescence spectra was effective in distinguishing glass fragments that could not be differentiated by their refractive indexes (RI).

The Japan Society for Analytical Chemistry has developed some new plastic certified reference materials (CRMs) for the analysis of mercury in polyester disks using XRF analysis. These CRMs (named as JSAC 0621 - 0625) were prepared by casting polyesters including a toluene solution of organometallic compounds as a standard. Concentrations of the five levels of mercury ranged from 0 to 250 mg/kg. Homogeneity tests of prepared disks had shown excellent results. Interlaboratory comparison study for the certification was performed by 15 laboratory participants. The z-scores in robust statistical method was applied for the evaluation of outliers. The certified values were assigned after discarding outliers. The uncertainties of certified values were determined as the confidence levels of 95%.

The crystal structure of α-hafnium bis(monohydrogen orthophosphate)monohydrate, an inorganic ion-exchanger, was solved by the X-ray Rietveld technique utilizing synchrotron radiation (SR) as the X-ray source. This compound is monoclinic with space group P21/n and cell parameters a=9.0142(1), b=5.25665(5), c=15.4768(2)A ??_ and β=101.636(1)°. Intensity data were collected by a capillary method with monochromatic X-rays of wavelength λ=1.49977(1)A. The results were compared with those obtained by a conventional X-ray source and the advantages of SR in Rietveld analysis were verified. Despite the difference in the Li-ion exchange behavior between the α-hafnium phosphate and the α-zirconium phosphate, both phases were found to be isostructural with each other.

The catadromous migration of freshwater eels, in which they migrate from freshwater streams to the sea to spawn1, is widely accepted. The proportion of time spent in freshwater and ocean habitats can be determined by studying the ratio of strontium (Sr) and calcium (Ca) in the otoliths (ear-stones) of the eels. Here we use this technique to show that Atlantic and Pacific eels collected in the ocean have spent their entire lifetime there and have never migrated into fresh water. This finding indicates that freshwater eels need not be catadromous, and that populations from the sea contribute primarily to future recruitment.

The Sb-121 Mossbauer parameters at 20 K for 23 antimony(III) compounds were obtained and the data are discussed in terms of known crystal structures. The isomer shifts and quadrupole coupling constants depend strongly on the type of configuration around the Sb(III) atoms with stereochemically active lone pair electrons.

X-ray absorption spectroscopy using synchrotron radiation has been applied to the investigation of the coordination geometries around Y, Zr and Nb atoms in metamict zircon, gadolinite, fergusonite, euxenite and samarskite. EXAFS and XANES spectra of their crystalline counterparts and synthetic compounds including ZrO2, Y2O3, YNbTiO6, YNbO4, LiNbO3, and NiNb2O6 were also measured for comparison. Metamict zircon shows a significant decrease in its Zr-O bond distances accompanying an increase in distortion of the Zr-O coordination polyhedra as compared with crystalline zircon. On the contrary, the average Nb-O bond distances and the symmetry of the coordination polyhedra around the Nb atoms in metamict euxenite and samarskite resemble those in the crystalline euxenite. Compared with crystalline fergusonite, a decrease in the distortion of the Nb-O octahedra is observed in metamict fergusonite. The structures of the second nearest neighbors (the metal-metal interactions) are largely disrupted in the metamict specimens except for metamict zircon and samarskite with high trivalent iron concentration. Nb in metamict samarskite is in octahedral coordination by oxygen and is similar to that in euxenite.