Projet de Convention relative au statut international des déplacés environnementaux

12 pagesInternational audienceTexte intégral du Projet de Convention relative au statut international des déplacés environnementaux élaboré en 2008 à l'Université de Limoges (CRIDEAU-CRDP-OMIJ-CIDCE

Monitorage du traumatisme crânien grave à la phase initiale par microdialyse cérébrale

BORDEAUX2-BU Santé (330632101) / SudocPARIS-BIUM (751062103) / SudocPARIS-Bib. Serv.Santé Armées (751055204) / SudocSudocFranceF

Progenitor/Stem Cells in Vascular Remodeling during Pulmonary Arterial Hypertension

International audiencePulmonary arterial hypertension (PAH) is characterized by an important occlusive vascular remodeling with the production of new endothelial cells, smooth muscle cells, myofibroblasts, and fibroblasts. Identifying the cellular processes leading to vascular proliferation and dysfunction is a major goal in order to decipher the mechanisms leading to PAH development. In addition to in situ proliferation of vascular cells, studies from the past 20 years have unveiled the role of circulating and resident vascular in pulmonary vascular remodeling. This review aims at summarizing the current knowledge on the different progenitor and stem cells that have been shown to participate in pulmonary vascular lesions and on the pathways regulating their recruitment during PAH. Finally, this review also addresses the therapeutic potential of circulating endothelial progenitor cells and mesenchymal stem cells

Interface Modulation to control dead layer effect and leakages in BST-based Varactors

International audienceEmerging communication technologies like 5G or Near Field Communication call for voltage tunable ferroelectric (FE) film capacitors to work at higher frequencies or lower voltage, thus requiring the reduction of the FE thickness to push away the piezoelectric resonance frequency and maintain high tunability. Unfortunately, two interface-related phenomena, the FE dead layer and leakage current, impede this evolution. Recent ab initio calculations showed the importance of the chemical bonding, polar discontinuity and rumpling at electrode / (Ba,Sr)TiO3 (BST) FE perovskite interfaces for polarization stabilization and Schottky barrier height (SBH) adjustment.1,2 In this work, a systematic electrode / BST interface engineering has been performed with the insertion of a thin La1-xSrxMnO3 Interface Control Layer with continuous composition variation (LSMOx ICL 0≤x≤1) by combinatorial Pulsed Laser Deposition. In the epitaxial (00l) STO(subs.)/La0.7Sr0.3MnO3/LSMOx (3uc)/SrTiO3 (0-4nm) heterostructure, the La3+/Sr2+ ratio controls the charge discontinuity at LSMOx/STO interface. As x↘ the nominal LSMOx terminal plane changes from Mn+4O2-2 to Mn+3O2-2 corresponding to a surface charge per unit cell variation from 0 to -1. Consequently, the LSMOx surface work-function increases leading to a transition from negative to positive band bending at LSMOx/STO interface as seen by UV photoemission spectroscopy (Figure a).3 Local I(V)s through LSMOx/STO interaces were acquired by AFM in contact mode. The SBH extracted from Fowler-Nordheim tunneling model fitting quantitatively agreed with UPS measurements (Figure b). DFT calculations reproduced the observed UPS band bending as a function of Sr content and underlined its correlation with therumpling in STO. Furthermore, to implement this knowledge in industrial BST varactors, we deposited polycrystalline Pt/LSMOx (5uc)/BST (200nm)/Au heterostructure on Sapphire. This varactors library was investigated by impedance spectroscopy (IS) to understand the effect of the LSMOx ICL on the tunability and losses (Figure c). The Sr content has an antisymmetric effect on the permittivity and the tunability, pointing towards a strong ICL influence on BST interface polarization. IS and Ferroelectric local characterizations will be pre

Interface Modulation to control dead layer effect and leakages in BST-based Varactors

International audienceEmerging communication technologies like 5G or Near Field Communication call for voltage tunable ferroelectric (FE) film capacitors to work at higher frequencies or lower voltage, thus requiring the reduction of the FE thickness to push away the piezoelectric resonance frequency and maintain high tunability. Unfortunately, two interface-related phenomena, the FE dead layer and leakage current, impede this evolution. Recent ab initio calculations showed the importance of the chemical bonding, polar discontinuity and rumpling at electrode / (Ba,Sr)TiO3 (BST) FE perovskite interfaces for polarization stabilization and Schottky barrier height (SBH) adjustment.1,2 In this work, a systematic electrode / BST interface engineering has been performed with the insertion of a thin La1-xSrxMnO3 Interface Control Layer with continuous composition variation (LSMOx ICL 0≤x≤1) by combinatorial Pulsed Laser Deposition. In the epitaxial (00l) STO(subs.)/La0.7Sr0.3MnO3/LSMOx (3uc)/SrTiO3 (0-4nm) heterostructure, the La3+/Sr2+ ratio controls the charge discontinuity at LSMOx/STO interface. As x↘ the nominal LSMOx terminal plane changes from Mn+4O2-2 to Mn+3O2-2 corresponding to a surface charge per unit cell variation from 0 to -1. Consequently, the LSMOx surface work-function increases leading to a transition from negative to positive band bending at LSMOx/STO interface as seen by UV photoemission spectroscopy (Figure a).3 Local I(V)s through LSMOx/STO interaces were acquired by AFM in contact mode. The SBH extracted from Fowler-Nordheim tunneling model fitting quantitatively agreed with UPS measurements (Figure b). DFT calculations reproduced the observed UPS band bending as a function of Sr content and underlined its correlation with therumpling in STO. Furthermore, to implement this knowledge in industrial BST varactors, we deposited polycrystalline Pt/LSMOx (5uc)/BST (200nm)/Au heterostructure on Sapphire. This varactors library was investigated by impedance spectroscopy (IS) to understand the effect of the LSMOx ICL on the tunability and losses (Figure c). The Sr content has an antisymmetric effect on the permittivity and the tunability, pointing towards a strong ICL influence on BST interface polarization. IS and Ferroelectric local characterizations will be pre

Interface Modulation to control dead layer effect and leakages in BST-based Varactors

International audienceEmerging communication technologies like 5G or Near Field Communication call for voltage tunable ferroelectric (FE) film capacitors to work at higher frequencies or lower voltage, thus requiring the reduction of the FE thickness to push away the piezoelectric resonance frequency and maintain high tunability. Unfortunately, two interface-related phenomena, the FE dead layer and leakage current, impede this evolution. Recent ab initio calculations showed the importance of the chemical bonding, polar discontinuity and rumpling at electrode / (Ba,Sr)TiO3 (BST) FE perovskite interfaces for polarization stabilization and Schottky barrier height (SBH) adjustment.1,2 In this work, a systematic electrode / BST interface engineering has been performed with the insertion of a thin La1-xSrxMnO3 Interface Control Layer with continuous composition variation (LSMOx ICL 0≤x≤1) by combinatorial Pulsed Laser Deposition. In the epitaxial (00l) STO(subs.)/La0.7Sr0.3MnO3/LSMOx (3uc)/SrTiO3 (0-4nm) heterostructure, the La3+/Sr2+ ratio controls the charge discontinuity at LSMOx/STO interface. As x↘ the nominal LSMOx terminal plane changes from Mn+4O2-2 to Mn+3O2-2 corresponding to a surface charge per unit cell variation from 0 to -1. Consequently, the LSMOx surface work-function increases leading to a transition from negative to positive band bending at LSMOx/STO interface as seen by UV photoemission spectroscopy (Figure a).3 Local I(V)s through LSMOx/STO interaces were acquired by AFM in contact mode. The SBH extracted from Fowler-Nordheim tunneling model fitting quantitatively agreed with UPS measurements (Figure b). DFT calculations reproduced the observed UPS band bending as a function of Sr content and underlined its correlation with therumpling in STO. Furthermore, to implement this knowledge in industrial BST varactors, we deposited polycrystalline Pt/LSMOx (5uc)/BST (200nm)/Au heterostructure on Sapphire. This varactors library was investigated by impedance spectroscopy (IS) to understand the effect of the LSMOx ICL on the tunability and losses (Figure c). The Sr content has an antisymmetric effect on the permittivity and the tunability, pointing towards a strong ICL influence on BST interface polarization. IS and Ferroelectric local characterizations will be pre

The Platelet-Derived Growth Factor Pathway in Pulmonary Arterial Hypertension: Still an Interesting Target?

International audienceThe lack of curative options for pulmonary arterial hypertension drives important research to understand the mechanisms underlying this devastating disease. Among the main identified pathways, the platelet-derived growth factor (PDGF) pathway was established to control vascular remodeling and anti-PDGF receptor (PDGFR) drugs were shown to reverse the disease in experimental models. Four different isoforms of PDGF are produced by various cell types in the lung. PDGFs control vascular cells migration, proliferation and survival through binding to their receptors PDGFRα and β. They elicit multiple intracellular signaling pathways which have been particularly studied in pulmonary smooth muscle cells. Activation of the PDGF pathway has been demonstrated both in patients and in pulmonary hypertension (PH) experimental models. Tyrosine kinase inhibitors (TKI) are numerous but without real specificity and Imatinib, one of the most specific, resulted in beneficial effects. However, adverse events and treatment discontinuation discouraged to pursue this therapy. Novel therapeutic strategies are currently under experimental evaluation. For TKI, they include intratracheal drug administration, low dosage or nanoparticles delivery. Specific anti-PDGF and anti-PDGFR molecules can also be designed such as new TKI, soluble receptors, aptamers or oligonucleotides

Plasticity-related gene-1 inhibits lysophosphatidic acid-induced vascular smooth muscle cell migration and proliferation and prevents neointima formation

International audiencePlasticity-related gene-1 (PRG-1) protects neuronal cells from lysophosphatidic acid (LPA) effects. In vascular smooth muscle cells (VSMCs), LPA was shown to induce phenotypic modulation in vitro and vascular remodeling in vivo. Thus we explored the role of PRG-1 in modulating VSMC response to LPA. PCR, Western blot, and immunofluorescence experiments showed that PRG-1 is expressed in rat and human vascular media. PRG-1 expression was strongly inhibited in proliferating compared with quiescent VSMCs both in vitro and in vivo (medial vs. neointimal VSMCs), suggesting that PRG-1 expression is dependent on the cell phenotype. In vitro, adenovirus-mediated overexpression of PRG-1 specifically inhibited LPA-induced rat VSMC proliferation and migration but not platelet-derived growth factor-induced proliferation. This effect was abolished by mutation of a conserved histidine in the lipid phosphate phosphatase family that is essential for interaction with lipid phosphates. In vivo, balloon-induced neointimal formation in rat carotid was significantly decreased in vessels infected with PRG-1 adenovirus compared with β-galactosidase adenovirus (−71%; P < 0.05). PRG-1 overexpression abolished the activation of the p42/p44 signaling pathway in LPA-stimulated rat VSMCs in culture and in balloon-injured rat carotids. Taken together, these findings provide the first evidence of a protective role of PRG-1 in the vascular media under pathophysiological conditions

POFA trial study protocol: a multicentre, double-blind, randomised, controlled clinical trial comparing opioid-free versus opioid anaesthesia on postoperative opioid-related adverse events after major or intermediate non-cardiac surgery

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