Severity of Hepatocyte Damage and Prognosis in Cirrhotic Patients Correlate with Hepatocyte Magnesium Depletion

We aimed to evaluate the magnesium content in human cirrhotic liver and its correlation with serum AST levels, expression of hepatocellular injury, and MELDNa prognostic score. In liver biopsies obtained at liver transplantation, we measured the magnesium content in liver tissue in 27 cirrhotic patients (CIRs) and 16 deceased donors with healthy liver (CTRLs) by atomic absorption spectrometry and within hepatocytes of 15 CIRs using synchrotron-based X-ray fluorescence microscopy. In 31 CIRs and 10 CTRLs, we evaluated the immunohistochemical expression in hepatocytes of the transient receptor potential melastatin 7 (TRPM7), a magnesium influx chanzyme also involved in inflammation. CIRs showed a lower hepatic magnesium content (117.2 (IQR 110.5–132.9) vs. 162.8 (IQR 155.9–169.8)  g/g; p < 0.001) and a higher percentage of TRPM7 positive hepatocytes (53.0 (IQR 36.8–62.0) vs. 20.7 (10.7–32.8)%; p < 0.001) than CTRLs. In CIRs, MELDNa and serum AST at transplant correlated: (a) inversely with the magnesium content both in liver tissue and hepatocytes; and (b) directly with the percentage of hepatocytes stained intensely for TRPM7. The latter also directly correlated with the worsening of MELDNa at transplant compared to waitlisting. Magnesium depletion and overexpression of its influx chanzyme TRPM7 in hepatocytes are associated with severity of hepatocyte injury and prognosis in cirrhosis. These data represent the pathophysiological basis for a possible beneficial effect of magnesium supplementation in cirrhotic patients

The origin of peculiar magnetic response of thin Co films intercalated between Graphene and Ir(111)

Le sujets de cette thèse sont l'évolution structurelle et la réponse magnétique particulière des films de cobalt observés lors de l'intercalation entre graphène et Ir (111).L'origine du comportement magnétique exotique de ces films n'a pas été trouvée encore. À cet égard, l'objectif final de ce travail est de sonder les effets de l'anisotropie structurale sur l'anisotropie magnétique.Plusieurs paramètres tels que l'épaisseur du film, les temps et les températures de la procedure du textit{annealing}, la présence de graphène et l'environnement local de Co ont été pris en compte comme possibles sources d'anisotropie structurale.Une analyse complète a été réalisée en utilisant des techniques complémentaires et avancées. Techniques comme la spectroscopie de photoélectrons de rayons X (XPS) et l'effet Kerr magnéto-optique (MOKE) ont fourni des informations sur la distribution de Co dans la direction perpendiculaire à la surface et sur la réponse magnétique. Cependant, techniques de rayonnement synchrotron comme la spectroscopie d'absorption de rayonnement X (XAS) et la diffraction de rayons X par incidence rasante (GIXD) ont sondé la structure locale et l'ordre à long terme des films.L'analyse présentée dans cette thèse inclut les effets de surface à l'interface Co/Ir, l'environnement local autour du Co, la structure cristalline du film, la rugosité du système et le désordre moyen.En particulier, l'évolution de ces paramètres est présentée et discutée en même temps que leur effet sur la réponse magnétique macroscopique des films intercalés.Les résultats démontrent que les traitements thermiques affectent la morphologie du Co, sa rugosité et sa coordination locale. Tels effets altèrent la structure du film affectant l'anisotropie magnétique globale. Cette information est utile à des fins applicatives. De plus, la description des modifications micro-structurales fournit un aperçu approfondi des propriétés physiques des films de Co intercalés.This thesis focuses on the structural evolution and the peculiar magnetic response of Cobalt films observed upon intercalation between Graphene and Ir(111).The origin of the exotic magnetic behaviour of such films cite{ROUGEMAILLE} has not been found yet. In this respect, the final goal of this work is to probe the effects of the structural anisotropy on the magnetic anisotropy.Several parameters such as: film thickness, annealing times and temperatures, Graphene presence, and Co local environment were taken into account as possible sources of structural anisotropy.A complete analysis was carried out using complementary, state-of-the-art techniques. While laboratory techniques such as X-ray Photoelectron Spectroscopy (XPS) and Magneto-Optic Kerr Effect (MOKE) provided information on the Co distribution along the direction perpendicular to the surface, and on the magnetic response, synchrotron radiation techniques such as X-ray Absorption Spectroscopy (XAS) and Grazing Incidence X-ray Diffraction (GIXD) probed the local structure and the long range order of the films.The analysis presented in this thesis includes the surface effects at the Co/Ir interface, the local Co environment, the crystalline structure of the film and the system roughness and average disorder.In particular, the evolution of such parameters is presented and discussed together with their effect on the macroscopic magnetic response of the intercalated films.The results demonstrate that thermal treatments affect Co morphology, roughness, and local coordination. Such effects alter the film structure affecting the overall magnetic anisotropy. This information alone is valuable for applicative purposes. Moreover, the description of the micro-structural modifications provides a deep insight into the physical properties of intercalated Co films

L'origine de la réponse magnétique particulière des films minces de Co intercalés entre Graphene et Ir(111)

This thesis focuses on the structural evolution and the peculiar magnetic response of Cobalt films observed upon intercalation between Graphene and Ir(111).The origin of the exotic magnetic behaviour of such films cite{ROUGEMAILLE} has not been found yet. In this respect, the final goal of this work is to probe the effects of the structural anisotropy on the magnetic anisotropy.Several parameters such as: film thickness, annealing times and temperatures, Graphene presence, and Co local environment were taken into account as possible sources of structural anisotropy.A complete analysis was carried out using complementary, state-of-the-art techniques. While laboratory techniques such as X-ray Photoelectron Spectroscopy (XPS) and Magneto-Optic Kerr Effect (MOKE) provided information on the Co distribution along the direction perpendicular to the surface, and on the magnetic response, synchrotron radiation techniques such as X-ray Absorption Spectroscopy (XAS) and Grazing Incidence X-ray Diffraction (GIXD) probed the local structure and the long range order of the films.The analysis presented in this thesis includes the surface effects at the Co/Ir interface, the local Co environment, the crystalline structure of the film and the system roughness and average disorder.In particular, the evolution of such parameters is presented and discussed together with their effect on the macroscopic magnetic response of the intercalated films.The results demonstrate that thermal treatments affect Co morphology, roughness, and local coordination. Such effects alter the film structure affecting the overall magnetic anisotropy. This information alone is valuable for applicative purposes. Moreover, the description of the micro-structural modifications provides a deep insight into the physical properties of intercalated Co films.Le sujets de cette thèse sont l'évolution structurelle et la réponse magnétique particulière des films de cobalt observés lors de l'intercalation entre graphène et Ir (111).L'origine du comportement magnétique exotique de ces films n'a pas été trouvée encore. À cet égard, l'objectif final de ce travail est de sonder les effets de l'anisotropie structurale sur l'anisotropie magnétique.Plusieurs paramètres tels que l'épaisseur du film, les temps et les températures de la procedure du textit{annealing}, la présence de graphène et l'environnement local de Co ont été pris en compte comme possibles sources d'anisotropie structurale.Une analyse complète a été réalisée en utilisant des techniques complémentaires et avancées. Techniques comme la spectroscopie de photoélectrons de rayons X (XPS) et l'effet Kerr magnéto-optique (MOKE) ont fourni des informations sur la distribution de Co dans la direction perpendiculaire à la surface et sur la réponse magnétique. Cependant, techniques de rayonnement synchrotron comme la spectroscopie d'absorption de rayonnement X (XAS) et la diffraction de rayons X par incidence rasante (GIXD) ont sondé la structure locale et l'ordre à long terme des films.L'analyse présentée dans cette thèse inclut les effets de surface à l'interface Co/Ir, l'environnement local autour du Co, la structure cristalline du film, la rugosité du système et le désordre moyen.En particulier, l'évolution de ces paramètres est présentée et discutée en même temps que leur effet sur la réponse magnétique macroscopique des films intercalés.Les résultats démontrent que les traitements thermiques affectent la morphologie du Co, sa rugosité et sa coordination locale. Tels effets altèrent la structure du film affectant l'anisotropie magnétique globale. Cette information est utile à des fins applicatives. De plus, la description des modifications micro-structurales fournit un aperçu approfondi des propriétés physiques des films de Co intercalés

L'origine de la réponse magnétique particulière des films minces de Co intercalés entre Graphene et Ir(111)

This thesis focuses on the structural evolution and the peculiar magnetic response of Cobalt films observed upon intercalation between Graphene and Ir(111).The origin of the exotic magnetic behaviour of such films cite{ROUGEMAILLE} has not been found yet. In this respect, the final goal of this work is to probe the effects of the structural anisotropy on the magnetic anisotropy.Several parameters such as: film thickness, annealing times and temperatures, Graphene presence, and Co local environment were taken into account as possible sources of structural anisotropy.A complete analysis was carried out using complementary, state-of-the-art techniques. While laboratory techniques such as X-ray Photoelectron Spectroscopy (XPS) and Magneto-Optic Kerr Effect (MOKE) provided information on the Co distribution along the direction perpendicular to the surface, and on the magnetic response, synchrotron radiation techniques such as X-ray Absorption Spectroscopy (XAS) and Grazing Incidence X-ray Diffraction (GIXD) probed the local structure and the long range order of the films.The analysis presented in this thesis includes the surface effects at the Co/Ir interface, the local Co environment, the crystalline structure of the film and the system roughness and average disorder.In particular, the evolution of such parameters is presented and discussed together with their effect on the macroscopic magnetic response of the intercalated films.The results demonstrate that thermal treatments affect Co morphology, roughness, and local coordination. Such effects alter the film structure affecting the overall magnetic anisotropy. This information alone is valuable for applicative purposes. Moreover, the description of the micro-structural modifications provides a deep insight into the physical properties of intercalated Co films.Le sujets de cette thèse sont l'évolution structurelle et la réponse magnétique particulière des films de cobalt observés lors de l'intercalation entre graphène et Ir (111).L'origine du comportement magnétique exotique de ces films n'a pas été trouvée encore. À cet égard, l'objectif final de ce travail est de sonder les effets de l'anisotropie structurale sur l'anisotropie magnétique.Plusieurs paramètres tels que l'épaisseur du film, les temps et les températures de la procedure du textit{annealing}, la présence de graphène et l'environnement local de Co ont été pris en compte comme possibles sources d'anisotropie structurale.Une analyse complète a été réalisée en utilisant des techniques complémentaires et avancées. Techniques comme la spectroscopie de photoélectrons de rayons X (XPS) et l'effet Kerr magnéto-optique (MOKE) ont fourni des informations sur la distribution de Co dans la direction perpendiculaire à la surface et sur la réponse magnétique. Cependant, techniques de rayonnement synchrotron comme la spectroscopie d'absorption de rayonnement X (XAS) et la diffraction de rayons X par incidence rasante (GIXD) ont sondé la structure locale et l'ordre à long terme des films.L'analyse présentée dans cette thèse inclut les effets de surface à l'interface Co/Ir, l'environnement local autour du Co, la structure cristalline du film, la rugosité du système et le désordre moyen.En particulier, l'évolution de ces paramètres est présentée et discutée en même temps que leur effet sur la réponse magnétique macroscopique des films intercalés.Les résultats démontrent que les traitements thermiques affectent la morphologie du Co, sa rugosité et sa coordination locale. Tels effets altèrent la structure du film affectant l'anisotropie magnétique globale. Cette information est utile à des fins applicatives. De plus, la description des modifications micro-structurales fournit un aperçu approfondi des propriétés physiques des films de Co intercalés

Co-Ir interface alloying induced by thermal annealing

Using angular resolved X-ray Photoelectron Spectroscopy (XPS), Magneto Optic Kerr Effect (MOKE) and X-ray Absorption Spectroscopy (XAS), we characterize the structural and magnetic evolution upon annealing of two thin Co films (8 and 9 Monolayers) deposited on Ir(111). The XAS data collected in the near Co K edge region (XANES), interpreted with ab-initio simulations, show that intermixing takes place at the Co-Ir interface. Using a linear combination analysis, we follow the intermixing during the thermally driven diffusion process. At 500 °C, the interface between Co and Ir(111) roughens slightly, but no alloy formation is detected. At 600 °C, the Co film loses integrity and MOKE data show a rearrangement of the magnetic domains. Annealing to higher temperatures results in CoxIr1 −  x alloy formation and Ir segregation on the surface

Evolution of electronic and magnetic properties in a series of iridate double perovskites Pr2-xSrxMgIrO6 (x=0,0.5,1.0)

Spin-orbit coupling (SOC) plays a crucial role in magnetic and electronic properties of 5d iridates. In this paper we have experimentally investigated the structural and physical properties of a series of Ir-based double perovskite compounds Pr2-xSrxMgIrO6(x = 0, 0.5, 1; hereafter abbreviated as PMIO, PSMIO1505, and PSMIO). Interestingly, these compounds have recently been proposed to undergo a transition from the spin-orbit-coupled Mott insulating phase at x = 0 to the elusive half-metallic antiferromagnetic (HMAFM) state with Sr doping at x = 1. However, our detailed magnetic and electrical measurements refute any kind of HMAFM possibility in either of the doped samples. In addition, we establish that within these Pr2-xSrxMgIrO6 double perovskites, changes in Ir-oxidation states (4+ for PMIO to 5+ for PSMIO via mixed 4+/5+ for PSMIO1505) lead to markedly different magnetic behaviors. While SOC on Ir is at the root of the observed insulating behaviors for all three samples, the correlated magnetic properties of these three compounds develop entirely due to the contribution from local Ir moments. Additionally, the magnetic Pr3+ (4f(2)) ions, instead of showing any kind of ordering, only contribute to the total paramagnetic moment. It is seen that the PrSrMgIrO6 sample does not order down to 2 K despite antiferromagnetic interactions. But, the d(5) iridate Pr2MgIrO6 shows a sharp antiferromagnetic (AFM) transition at around 14 K, and in the mixed valent Pr1.5Sr0.5MgIrO6 sample the AFM transition is shifted to a much lower temperature (similar to 6 K) due to weakening of the AFM exchange

Structure of the Surface Region of Stainless Steel: Bulk and Thin Films

The surface region of austenitic stainless steel (SS) is investigated by synchrotronX-ray powder diffraction (XRPD) and X-ray absorption near edge structure (XANES)measurements, because its composition and structure are crucial for the corrosionresistance of SS. Grazing incidence XRPD of a polished AISI 304 bulk steel sampleshows that the near-surface structure is modified. The concentration of the ferritephase of Fe, a typical minority phase in AISI 304, increases gradually from 10% to30% when approaching the surface from 150 nm depth. XANES Fe K-edgeinvestigations of ultrathin, sputter-deposited films also reveal much larger ferritefractions than expected from the austenitic steel composition of the films. Reasonsfor the increased ferrite fraction in the surface region of bulk steel and thin films arediscussed. However, right at the surface, the trend reverses. Analysis of XANES datafor an ultrathin, 4 nm SS film shows that 80% of Fe is oxidized and 20% of metallicFe is present only in austenite structure, suggesting that ferritic iron is preferentiallysubject to oxidation. The austenitic Fe is located at more than 2–3 nm below thesurface where the Ni concentration is >10%