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Journal of analytical atomic spectrometry 37(1), 114 - 129 (2022). doi:10.1039/D1JA00271F, Redox processes activated by environmental factors have been identified as the main cause of the chromatic alterations of a number of artists' pigments, including the yellow pigment orpiment (As$_2$S$_3$). Although a general comprehension of the mechanisms has been provided through characterization of degradation compounds of As$_2$S$_3$, experimental evidences to prove how other paint components and how different environmental agents influence the formation pathways of specific secondary compounds are still lacking. Thus, it becomes fundamental to develop a methodological strategy which enable achieving a discrimination among the causes affecting the chemical stability of more heterogenous As$_2$S$_3$-based paints and defining the mechanism through which the alteration establishes and evolves, with the ultimate goal of optimizing the preventive conservation measures of unique masterpieces. In this paper, we propose a comprehensive multi-material and multi-method approach based on the combination of synchrotron radiation X-ray micro-analytical techniques (i.e., X-ray diffraction, X-ray fluorescence and X-ray absorption near edge structure spectroscopy at S K-/Ag L$_3$-/As K-edges) and vibrational micro-spectroscopy methods to unveil the causes and mechanism of darkening of ���fake-gilded��� decorations in tempera paintings, originally consisting of an unusual mixture of A$_2$S$_3$ and metallic silver (Ag$^0$). Such degradation process is a not yet understood phenomenon threatening a series of Old Master paintings, including those by the Italian painters Cimabue and Pietro Lorenzetti. The high specificity, sensitivity and lateral resolution of the employed analytical methods allowed providing first-time evidence for the presence of black acanthite ($��$-Ag$_2$S), mimetite [Pb$_5$(AsO$_4$)$_3$Cl] and syngenite [K$_2$Ca(SO$_4$)$_2$��H$_2$O] as degradation products of the ���fake-gilded��� decorations in the Maest�� by Cimabue (Church of Santa Maria dei Servi, Bologna, Italy). Furthermore, the study of the painting combined with that of tempera paint mock-ups permitted to explore and define the environmental agents and internal factors causing the darkening, by proving that: (i) Ag$^0$ and moisture are key-factors for triggering the transformation of As$_2$S$_3$ to $��$-Ag$_2$S and As-oxides; (ii) S$^2$--ions arising from the degradation of A$_2$S$_3$ are the main responsible for the formation of $��$-Ag$_2$S; (iii) light exposure strengthens the tendency of the paint components towards alteration. Based on our findings, we finally propose a degradation mechanism of As$_2$S$_3$/Ag$^0$-based tempera paints., Published by ChemSoc, Cambridge

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International audience; The impact on human health of long-term exposure to low doses of silver nanoparticles (AgNPs) remainsunderstudied. Cellular studies have shown the intracellular dissolution of AgNPs within endolysosomesfollowed by Ag(I) binding to biomolecular thiolate-containing molecules. However, the precise subcellulardistribution of Ag(I) and the nature of the disrupted physiological pathways remained unknown. Novelimaging approaches enabled us to visualize the trafficking of AgNP-containing lysosomes towards aperinuclear location and a nuclear transfer of Ag(I) species with accumulation in the nucleoli. These Ag(I)species impaired nuclear receptor activity, disrupting critical mechanisms of liver physiology in low doseexposure scenarios, thus justifying further research into defining a framework for the safe use of AgNPs.

Metallic implants are frequently used in medicine to support and replace degenerated tissues. Implant loosening due to particle exposure remains a major cause for revision arthroplasty. The exact role of metal debris in sterile peri‐implant inflammation is controversial, as it remains unclear whether and how metals chemically alter and potentially accumulate behind an insulating peri‐implant membrane, in the adjacent bone and bone marrow (BM). An intensively focused and bright synchrotron X‐ray beam allows for spatially resolving the multi‐elemental composition of peri‐implant tissues from patients undergoing revision surgery. In peri‐implant BM, particulate cobalt (Co) is exclusively co‐localized with chromium (Cr), non‐particulate Cr accumulates in the BM matrix. Particles consisting of Co and Cr contain less Co than bulk alloy, which indicates a pronounced dissolution capacity. Particulate titanium (Ti) is abundant in the BM and analyzed Ti nanoparticles predominantly consist of titanium dioxide in the anatase crystal phase. Co and Cr but not Ti integrate into peri‐implant bone trabeculae. The characteristic of Cr to accumulate in the intertrabecular matrix and trabecular bone is reproducible in a human 3D in vitro model. This study illustrates the importance of updating the view on long‐term consequences of biomaterial usage and reveals toxicokinetics within highly sensitive organs., Spatially micron‐ and nanoresolved synchrotron X‐ray fluorescence analyses of peri‐implant cancellous bone reveal specific distribution and accumulation patterns of metals released from alloys frequently used in knee and hip arthroplasty. These new insights of the local toxicokinetics of metallic debris prove that cobalt, chromium, and titanium exposure also occurs behind the insulating implant membrane, in the bone and bone marrow.

Additional Methods. Figure S1. Nano-X-ray fluorescence (XRF) maps of four skin and three lymph node samples analyzed at ID16B. Figure S2. Nano-X-ray fluorescence (XRF) maps of selected inks analyzed at ID16B. Figure S3. Calculation of Ni and Cr contamination in pig skin and inks. Figure S4. T-cell infiltration in tattoo allergy sample. Table S1. Titanium XANES spectra of eight human skin and six lymph node samples as well as a skin allergy biopsy were fitted to pure anatase and rutile spectra of known standards. Table S2. MALDI-MS analysis of organic pigments in skin and lymph node samples. No pigments were found in the control samples. Table S3. Cr K-edge micro-XANES spectra of human skin and lymph node samples were fitted to spectra of known Cr standards. Table S4. Ni K-edge nano-XANES spectra of human skin and lymph node samples were fitted to known Ni standards. Table S5. ICP-MS analysis of elements in skin and lymph node samples. Increased values compared to skin or lymph node (LN) control samples are marked in bold. Table S6. Table-top X-ray fluorescence (XRF) analysis of microtome blades used for sample preparation and commercial tattoo needles. Tattoo needles analyzed derived from six different brands. Data are displayed as mean and standard deviation of n = 2 measurements. (DOCX 3000 kb)

Spectroscopy beamlines at the ESRF are equipped with a generic model of double crystal monochromator, originally acquired in the 1990's. After over 15 years of continuous service, their conception, although pioneering 20 years ago, can no longer meet the challenge of present and future scientific goals in terms of position and angular stability, thermal stability, cooling system, vibration, control and feedback, particularly in view of the ESRF - EBS upgrade. Considering the above issues, a feasibility phase was launched to develop a prototype DCM dedicated to future spectroscopy applications at the ESRF. Specifications : derived from expected performance of the EBS upgrade and scientific objectives - are extremely challenging, especially in terms of mechanical and thermal stability and impose the adoption of several innovative design strategies. The prototype is currently in the assembly phase and tests of the complete system are planned before the end of 2018. An overview of the DCM prototype project will be given, including specifications, major design options implemented and various validated concepts. Current project status and first test results will also be presented., Proceedings of the Mechanical Eng.~Design of Synchrotron Radiation Equipment and Instrumentation, MEDSI2018, Paris, France

WOS:000438212400292

We have performed x-ray specular reflectivity and scattering measurements of thermally slumped glass substrates on x-ray diffractometers utilizing a rotating anode x-ray source at the Danish Space Research Institute (DSRI) and synchrotron radiation at the European Synchrotron Radiation Facility (ESRF) optics Bending Magnet beamline. In addition, we tested depth graded W/Si multilayer-coated slumped glass using x-ray specular reflectivity measurements at 8.048 keV and 28 keV and energy-dispersive measurements in the 20-50 keV rang at a double-axis diffractometer at the Orsted Laboratory, University of Copenhagen. The thermally slumped glass substrates will be used to fabricate the hard x-ray grazing incidence optics for the High-Energy Focusing Telescope. We compared the measurements to the SODART- mirrors from the SRG telescope mission program. The surface scatter measurement of the thermally slumped glass substrates yields Half Power Diameters (HPD's) of single- bounce mirrors of full-illuminated lengths of ~ 40 arcseconds for typical substrates and as low as ~ 10 arcseconds for the best substrates, whereas the SODART mirrors yields HPD's of ~ 80 arcseconds with very little variation. Both free-standing glass substrates and prototype mounted and multilayer-coated optics were tested. The result demonstrate that the surface scatter contribution, plus any contribution from the mounting procedure, to the Half Power Diameter from a telescope using the slumped glass optics will be in the subarcminute range.In addition we measured low surface microroughness, yielding high reflectivity, from the glass substrates, as well as from the depth graded W/Si multilayer-coated glass glass (interfacial width 4.2 Å).