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Abstract: The salt films formed on metal surfaces dissolving inside artificial corrosion pits formed in 1 M HCl have been probed with synchrotron X-ray diffraction. NiCl2 · 6H2O is the main phase in the salt film on nickel, whereas salt films on both iron and 316 L stainless steel are predominantly FeCl2 · 4H2O. However, the salt film on iron has a very fine homogeneous crystallite size whereas that on stainless steel is much coarser. The potential-dependence of the film formed on iron has been determined.

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Abstract: The Moa Bay Ni–Co laterite deposits, placed in the so-called Mayari–Baracoa ophiolitic belt (eastern Cuba), are oxide type. Despite its geological relevance and economical impact no detailed studies exist with regards to cristallochemical characterization of Ni incorporated in (or attached to) the main Ni-containing minerals forming the lateritic profile. A sample corresponding to the ore limonite horizon has been studied by microfocus Raman, micro X-ray diffraction (μXRD), electron probe micro analysis (EPMA) and synchrotron radiation microfocus X-ray absorption spectroscopy (XAS) to gain structural and chemical information on Ni. The data obtained has revealed that Ni is preferably accumulated in quantities up to 21 wt.% in “lithiophorite–asbolane” intermediates. The local environment of Ni shows Ni–Mn distances ∼3.5 Å suggesting that Ni is sorbed mostly in inner-sphere complexes sitting on Mn vacancies and at the edge of the Mn layers. However it is shown that in the presence of Al the Ni is incorporated within the “lithiophorite–asbolane” intermediate by developing brucite-like interlayers. The understanding of Ni sorption mechanisms within the limonite horizon suggests that combined physicochemical factors such as soil porosity and pH regime have important implications for Ni mobility across the profile.

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Abstract: We have used synchrotron Fe-XANES, XRS, microRaman, and SEM-TEM analyses of Stardust track 41 slice and track 121 terminal area slices to identify Fe oxide (magnetite-hematite and amorphous oxide), Fe-Ti oxide, and V-rich chromite (Fe-Cr-V-Ti-Mn oxide) grains ranging in size from 200 nm to ∼10 μm. They co-exist with relict FeNi metal. Both Fe-XANES and microRaman analyses suggest that the FeNi metal and magnetite (Fe2O3FeO) also contain some hematite (Fe2O3). The FeNi has been partially oxidized (probably during capture), but on the basis of our experimental work with a light-gas gun and microRaman analyses, we believe that some of the magnetite-hematite mixtures may have originated on Wild 2. The terminal samples from track 121 also contain traces of sulfide and Mg-rich silicate minerals. Our results show an unequilibrated mixture of reduced and oxidized Fe-bearing minerals in the Wild 2 samples in an analogous way to mineral assemblages seen in carbonaceous chondrites and interplanetary dust particles. The samples contain some evidence for terrestrial contamination, for example, occasional Zn-bearing grains and amorphous Fe oxide in track 121 for which evidence of a cometary origin is lacking.

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Abstract: X-ray absorption near-edge structure (XANES) spectroscopy was used to examine the oxidation state of Zn, Fe and Cu in 22 normal and 23 tumour regions spread over 30 formalin-fixed, paraffin-embedded tissue samples of human primary invasive breast cancer. A micro-mapping analysis of the metal distribution in the tissue was performed prior to the XANES analysis to identify and localise the metals in the tumour and normal tissue regions. The aim of this study was to identify the oxidation state of Zn, Fe and Cu in normal and tumour tissues of the breast, in order to correlate the oxidation state of these elements with the carcinogenesis process. The position of the Zn K-edge in normal and tumour tissues suggests that Zn exists in a bounded form. The shape of the Cu K-edge XANES spectra and the first derivative spectra of normal and tumour tissues shows that a significant portion of the total copper is present as Cu (I). Nevertheless, the position of the edges in the normal and tumour tissue spectra does not exclude the presence of Cu (II). The shape and position of both normal and tumour regions of the tissue suggest that they contain mixtures of Fe (II) and Fe (III) ions with a significant fraction being Fe (III). However, normal tissue regions were found to have a higher fraction of Fe (II) compared to the tumour tissues. In order to estimate the best target for therapy, more information is required about the relative abundance of Zn, Fe and Cu binding proteins, their oxidation state and their localisation at the subcellular level. Copyright © 2010 John Wiley & Sons, Ltd.