429 research outputs found

    Analysis of the iron coatings formed during marcasite and arsenopyrite oxidation at neutral-alkaline conditions

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    In order to study the nature of the precipitates formed on arsenopyrite and marcasite after reacting with neutral to alkaline solutions, a combination of techniques including Scanning Electron Microscope-Energy Dispersive Spectroscopy (SEM-EDS), X-ray Photoelectron Spectroscopy (XPS) and synchrotron-based techniques such as micro-X-Ray diffraction (”XRD) and Micro-X-ray Absorption Near Edge Structure (”XANES) have been used. The results showed that the oxidation of marcasite and arsenopyrite under neutral to alkaline conditions leads to the formation of an Fe rich coating which seems to prevent the oxidation of these sulphides. SEM observations confirmed the presence newly-formed phases after the sulphides reaction under the studied conditions. XPS analysis showed that iron, sulphur and arsenic in the case of the arsenopyrite are in oxidized states in the sulphide surfaces. The microscale analysis of the S and Fe speciation performed by ”XANES suggested that due to the sulphide oxidation an increase in the oxidation state of those elements took place together with an increase of the sulphate content in the surface layer (grain boundary). Micro-X-ray diffraction results indicated that goethite (a-FeOOH) is the only crystalline newly-formed phase when the reaction occurs at pH 12 whereas at lower pH the products formed on the sulphide surfaces seem to be poorly crystalline and they do not contribute to the diffraction effects in the XRD diagrams

    Application of Synchrotron Radiation-Based Micro-Analysis on Cadmium Yellows in Pablo Picasso's Femme

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    The cultural heritage community is increasingly exploring synchrotron radiation (SR) based techniques for the study of art and archaeological objects. When considering heterogeneous and complex micro-samples, such as those from paintings, the combination of different SR X-ray techniques is often exploited to overcome the intrinsic limitations and sensitivity of the single technique. Less frequently, SR X-ray analyses are combined with SR micro-photoluminescence or micro-Fourier Transform Infrared spectroscopy, which provide complementary information on the molecular composition, offering a unique integrated analysis approach. Although the spatial correlation between the maps obtained with different techniques is not straightforward due to the different volumes probed by each method, the combination of the information provides a greater understanding and insight into the paint chemistry. In this work, we discuss the advantages and disadvantages of the combination of X-ray techniques and SR-based photoluminescence through the study of two paint micro-samples taken from Pablo Picasso's Femme (1907). The painting contains two cadmium yellow paints (based on CdS): one relatively intact and one visibly degraded. SR micro-analyses demonstrated that the two Cd-yellow paints differ in terms of structure, chemical composition, and photoluminescence properties. In particular, on the basis of the combination of different SR measurements, we hypothesize that the degraded yellow is based on nanocrystalline CdS with high presence of Cd(OH)Cl. These two characteristics have enhanced the reactivity of the paint and strongly influenced its stability

    Differential protein folding and chemical changes in lung tissues exposed to asbestos or particulates

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    Environmental and occupational inhalants may induce a large number of pulmonary diseases, with asbestos exposure being the most risky. The mechanisms are clearly related to chemical composition and physical and surface properties of materials. A combination of X-ray fluorescence (\u3bcXRF) and Fourier Transform InfraRed (\u3bcFTIR) microscopy was used to chemically characterize and compare asbestos bodies versus environmental particulates (anthracosis) in lung tissues from asbestos exposed and control patients. \u3bcXRF analyses revealed heterogeneously aggregated particles in the anthracotic structures, containing mainly Si, K, Al and Fe. Both asbestos and particulates alter lung iron homeostasis, with a more marked effect in asbestos exposure. \u3bcFTIR analyses revealed abundant proteins on asbestos bodies but not on anthracotic particles. Most importantly, the analyses demonstrated that the asbestos coating proteins contain high levels of \u3b2-sheet structures. The occurrence of conformational changes in the proteic component of the asbestos coating provides new insights into long-term asbestos effects

    Oral bisphosphonate compliance and persistence: a matter of choice?

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    Compliance to oral bisphosphonates is suboptimal, with negative consequences of increased healthcare utilization and less effective fracture risk reduction. Extending dose interval increased adherence only moderately. We used literature derived from multiple chronic conditions to examine the problem of noncompliance with osteoporosis medication. We reviewed the literature on adherence to osteoporosis medication as well as that across multiple chronic conditions to understand what is known about the cause of the poor adherence. Poor compliance to oral medications is due mostly, not to forgetfulness, but to deliberate choice. Gender differences and style of healthcare management also play a role. Preliminary data suggest psychobehavioral interventions may help to improve motivation. We need to understand better reasons for poor compliance before effective interventions can be developed. Forgetfulness is only a small part of poor compliance. Patient preferences must be considered in medication decision making

    The “Historical Materials BAG”: A New Facilitated Access to Synchrotron X-ray Diffraction Analyses for Cultural Heritage Materials at the European Synchrotron Radiation Facility

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    The European Synchrotron Radiation Facility (ESRF) has recently commissioned the new Extremely Brilliant Source (EBS). The gain in brightness as well as the continuous development of beamline instruments boosts the beamline performances, in particular in terms of accelerated data acquisition. This has motivated the development of new access modes as an alternative to standard proposals for access to beamtime, in particular via the “block allocation group” (BAG) mode. Here, we present the recently implemented “historical materials BAG”: a community proposal giving to 10 European institutes the opportunity for guaranteed beamtime at two X-ray powder diffraction (XRPD) beamlines—ID13, for 2D high lateral resolution XRPD mapping, and ID22 for high angular resolution XRPD bulk analyses—with a particular focus on applications to cultural heritage. The capabilities offered by these instruments, the specific hardware and software developments to facilitate and speed-up data acquisition and data processing are detailed, and the first results from this new access are illustrated with recent applications to pigments, paintings, ceramics and wood

    J Med Internet Res

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    Background: Immune checkpoint inhibitors (ICIs) are increasingly used to treat several types of tumors. Impact of this emerging therapy on patients’ health-related quality of life (HRQoL) is usually collected in clinical trials through standard questionnaires. However, this might not fully reflect HRQoL of patients under real-world conditions. In parallel, users’ narratives from social media represent a potential new source of research concerning HRQoL. Objective: The aim of this study is to assess and compare coverage of ICI-treated patients’ HRQoL domains and subdomains in standard questionnaires from clinical trials and in real-world setting from social media posts. Methods: A retrospective study was carried out by collecting social media posts in French language written by internet users mentioning their experiences with ICIs between January 2011 and August 2018. Automatic and manual extractions were implemented to create a corpus where domains and subdomains of HRQoL were classified. These annotations were compared with domains covered by 2 standard HRQoL questionnaires, the EORTC QLQ-C30 and the FACT-G. Results: We identified 150 users who described their own experience with ICI (89/150, 59.3%) or that of their relative (61/150, 40.7%), with 137 users (91.3%) reporting at least one HRQoL domain in their social media posts. A total of 8 domains and 42 subdomains of HRQoL were identified: Global health (1 subdomain; 115 patients), Symptoms (13; 76), Emotional state (10; 49), Role (7; 22), Physical activity (4; 13), Professional situation (3; 9), Cognitive state (2; 2), and Social state (2; 2). The QLQ-C30 showed a wider global coverage of social media HRQoL subdomains than the FACT-G, 45% (19/42) and 29% (12/42), respectively. For both QLQ-C30 and FACT-G questionnaires, coverage rates were particularly suboptimal for Symptoms (68/123, 55.3% and 72/123, 58.5%, respectively), Emotional state (7/49, 14% and 24/49, 49%, respectively), and Role (17/22, 77% and 15/22, 68%, respectively). Conclusions: Many patients with cancer are using social media to share their experiences with immunotherapy. Collecting and analyzing their spontaneous narratives are helpful to capture and understand their HRQoL in real-world setting. New measures of HRQoL are needed to provide more in-depth evaluation of Symptoms, Emotional state, and Role among patients with cancer treated with immunotherapy
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