Hyperaccumulators are attractive models for studying metal(loid) homeostasis, and probing the spatial distribution and coordination chemistry of metal(loid)s in their tissues is important for ...advancing our understanding of their ecophysiology. X-ray elemental mapping techniques are unique in providing in situ information, and with appropriate sample preparation offer results true to biological conditions of the living plant. The common platform of these techniques is a reliance on characteristic X-rays of elements present in a sample, excited either by electrons (scanning/transmission electron microscopy), protons (proton-induced X-ray emission) or X-rays (X-ray fluorescence microscopy). Elucidating the cellular and tissue-level distribution of metal(loid)s is inherently challenging and accurate X-ray analysis places strict demands on sample collection, preparation and analytical conditions, to avoid elemental redistribution, chemical modification or ultrastructural alterations. We compare the merits and limitations of the individual techniques, and focus on the optimal field of applications for inferring ecophysiological processes in hyperaccumulator plants. X-ray elemental mapping techniques can play a key role in answering questions at every level of metal(loid) homeostasis in plants, from the rhizosphere interface, to uptake pathways in the roots and shoots. Further improvements in technological capabilities offer exciting perspectives for the study of hyperaccumulator plants into the future.
The proton induced K X-ray emission spectra of several different phosphorus and sulfur compounds were recorded with the new parallel-beam wavelength dispersive X-ray emission spectrometer. The ...spectrometer was installed recently at the external proton microbeam at the J. Stefan Institute to perform high energy resolution in-air micro-PIXE analysis in the tender X-ray range. Reported measurements are used to probe the capabilities of the spectrometer to perform also chemical state analysis. For phosphorus measurements, where the energy resolution of the spectrometer is the highest, a clear correlation between measured energy position of the Kα emission line and the phosphorus formal oxidation state is obtained. Chemical contrast is increased further in the Kβ emission spectra reflecting the structure of occupied valence molecular orbitals defined by the first coordination shell around the central phosphorus atom. A reasonable chemical contrast is maintained also in the sulfur Kβ emission spectra, despite the fact that the energy resolution of the spectrometer declines with increasing X-ray energy. Finally, an example of phosphorus speciation in reference biological material is presented, demonstrating the feasibility of the new setup to extend the capabilities of in-air micro-PIXE analysis towards chemical speciation.
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•The PB-WDS X-ray emission spectrometer was used to perform chemical state analysis of P and S.•Measured phosphorus Kα emission spectra exhibit energy shifts correlated with the formal oxidation state.•Kβ emission spectra of P and S reflect the coordination of neighboring atoms bound to the central phosphorus or sulfur atom.•The phosphorus spectra collected from standard reference biological material was used to specify its chemical state as a phosphate.
Phyllanthus balgooyi (Phyllanthaceae), one of > 20 nickel (Ni) hyperaccumulator plant species known in Sabah (Malaysia) on the island of Borneo, is remarkable because it contains > 16 wt% Ni in its ...phloem sap, the second highest concentration of Ni in any living material in the world (after Pycnandra acuminata (Sapotaceae) from New Caledonia with 25 wt% Ni in latex). This study focused on the tissue‐level distribution of Ni and other elements in the leaves, petioles and stem of P. balgooyi using nuclear microprobe imaging (micro‐PIXE). The results show that in the stems and petioles of P. balgooyi Ni concentrations were very high in the phloem, while in the leaves there was significant enrichment of this element in the major vascular bundles. In the leaves, cobalt (Co) was codistributed with Ni, while the distribution of manganese (Mn) was different. The highest enrichment of calcium (Ca) in the stems was in the periderm, the epidermis and subepidermis of the petiole, and in the palisade mesophyll of the leaf. Preferential accumulation of Ni in the vascular tracts suggests that Ni is present in a metabolically active form. The elemental distribution of P. balgooyi differs from those of many other Ni hyperaccumulator plant species from around the world where Ni is preferentially accumulated in leaf epidermal cells.
Cadmium and zinc share many similar physiochemical properties, but their compartmentation, complexation and impact on other mineral element distribution in plant tissues may drastically differ. In ...this study, we address the impact of 10 μm Cd or 50 μm Zn treatments on ion distribution in leaves of a metallicolous population of the non‐hyperaccumulating species Zygophyllum fabago at tissue and cell level, and the consequences on the plant response through a combined physiological, proteomic and metabolite approach. Micro‐proton‐induced X‐ray emission and laser ablation inductively coupled mass spectrometry analyses indicated hot spots of Cd concentrations in the vicinity of vascular bundles in response to Cd treatment, essentially bound to S‐containing compounds as revealed by extended X‐ray absorption fine structure and non‐protein thiol compounds analyses. A preferential accumulation of Zn occurred in vascular bundle and spongy mesophyll in response to Zn treatment, and was mainly bound to O/N‐ligands. Leaf proteomics and physiological status evidenced a protection of photosynthetically active tissues and the maintenance of cell turgor through specific distribution and complexation of toxic ions, reallocation of some essential elements, synthesis of proteins involved in photosynthetic apparatus or C‐metabolism, and metabolite synthesis with some specificities regarding the considered heavy metal treatment.
Micro-PIXE imaging of the rib bones of rats Yakumaru, Haruko; Kato, Yugo; Oikawa, Masakazu ...
Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms,
August 2024, 2024-08-00, Letnik:
553
Journal Article
Recenzirano
The ribs are bones that constitute the ribcage and consist of three regions: cartilage, costochondral junction with growth plate structures, and hard bone. In this study, frozen sections of rat ribs ...were prepared, and the distributions of calcium (Ca), phosphorus (P), potassium (K), and sulfur (S) were examined using particle-induced X-ray emission with microprobe (micro-PIXE) analysis. Areas with high Ca and P accumulation were observed in the interior of the rib cartilage. Histograms comparing the Ca accumulation in the three rib regions showed that the mode of accumulation of Ca in the cartilage are similar to that of the costochondral junction but distinct from that of the hard bone. The cartilage section did not possess an alkaline phosphatase-concentrated area that reflects the hard bone mineralization and is enriched in the costochondral junction. These data indicate differences in the mineralization process between cartilage and hard bones.
The scanning light ion microprobe in Uppsala – Status in 2022 Nagy, Gyula; Whitlow, Harry J.; Primetzhofer, Daniel
Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms,
12/2022, Letnik:
533
Journal Article
Recenzirano
Odprti dostop
The Scanning Light Ion Microprobe in Uppsala (SLIM-UP) was originally installed during 1989/90. Since then, the microprobe has undergone several minor and major modifications. The present ...configuration is a re-build of the SLIM-UP, that is now connected to the 5 MV tandem Pelletron® accelerator of the Tandem Laboratory, Uppsala University. We give an overview of the present status of the Uppsala microprobe facility, including a detailed description of the components and a recent resolution test. In addition, we present the most recent technical developments whereby, the system is able to quickly image large area samples, to reliably identify individual microparticles, and to analyse them separately. Optimal parameters for a certain system can be found by simple test measurements on dummy samples. Our test scenario comprises of Fe particles embedded in a light matrix, representing human tissue. We found a good compromise between the required analysis time and particle detection efficiency.
Copper ores recovered at the third millennium bce settlement of São Pedro, Portugal, were characterized by micro‐Raman spectroscopy, micro‐energy dispersive X‐ray spectrometry (micro‐EDXRF) and ...micro‐particle‐induced X‐ray emission spectrometry (micro‐PIXE). The collection shows the common presence of secondary copper minerals (malachite, pseudomalachite and libethenite) combined with iron oxyhydroxides (hematite and goethite), while arsenic‐rich minerals are absent and, therefore, can be excluded as the source of arsenical copper. Overall, these copper ores suggest a primitive technology involving the exploitation of the superficial zone of ore bodies and reliant on the fortuitous finding of arsenic‐rich sources to produce the arsenical copper alloy frequently present among metallic collections of the Iberian Peninsula.
We investigated element composition ratios in two sets of sequentially collected airborne particulate matter (PM) samples obtained through the automatic sampler of the Atmospheric Environmental ...Regional Observation System (AEROS). A series of micro-PIXE analyses and imaging were performed on a PTFE (Polytetrafluoroethylene) membrane tape filter corresponding to two hourly time slots through a high-concentration air pollution event from 26th to 27th March 2020 sampled at Ota, Japan (36.290° N, 139.381° E) by utilizing an external 3 MeV proton microprobe. Latent variables of sequentially collected PM samples were analyzed by the non-linear least square method and classified by those clustering driven by house-made data analysis software. Micro-PIXE imaging effectively confirmed the presence of large elemental agglomerations on the PTFE membrane tape filter of AEROS that often appeared as outliners in data analysis.
Abstract
To extract information on elemental components and PM characteristics from smoke number (SN) filter paper, we were performed elemental analysis by micro-PIXE. As a result of elemental ...analysis of the SN filter, information on the elemental composition of jet engine exhaust PM was obtained. Regarding the SN filter, jet engine exhaust PM have been collected for each difference in engine thrust of various aircraft engines at aircraft turbine engines test cells around the world. By periodically analyzing the elemental composition of such the SN filter, it is possible to grasp the characteristics of the emission PM of each aircraft engine and the transformation of the elemental composition of the emission PM with the passage of time of the jet engine. This was thought to lead to the evaluation of jet engine.
Antique objects are known to have been brightly colored. However, the appearance of these objects has changed over time and paint traces are rarely preserved. The surface of ivory objects (8th ...century B.C., Syria) from the Louvre museum collection (Paris) have been non-invasively studied by simultaneous particle-induced X-ray emission (PIXE) and Rutherford and elastic backscattering spectrometry (RBS/EBS) micro-imaging at the AGLAE facility (C2RMF, Paris). Qualitative 2D chemical images of elements ranging from Na to Pb on the surface of the ancient ivory carvings provide evidence of lost polychromy and gilding. Quantitative PIXE data of specific areas allow discrimination between traces of sediments and former polychromy. Different shades of blue can be differentiated from particular Pb/Cu ratios. The characterization of gilding based on RBS data demonstrates the exceptional technological skills of the Phoenician craftsmen supposed to have carved the Arslan Tash ivories. More precise reconstructions of the original polychromy compared to previous studies and a criterion for the authentication of ancient gilded ivory object are proposed.
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•Particle-induced X-ray emission and Rutherford/elastic backscattering spectrometry.•Non-invasive chemical imaging reveals lost polychromy and gilding of ancient ivories.•Discrimination between sediments and polychromy and differentiation of color shades.•Comparing ivories from known archaeological context and pieces from the art market.
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