38 research outputs found

    Basin tectonic history and paleo-physiography of the pelagian platform, northern Tunisia, using vitrinite reflectance data

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    Constraining the thermal, burial and uplift/exhumation history of sedimentary basins is crucial in the understanding of upper crustal strain evolution and also has implications for understanding the nature and timing of hydrocarbon maturation and migration. In this study, we use Vitrinite Reflectance (VR) data to elucidate the paleo‐physiography and thermal history of an inverted basin in the foreland of the Atlasic orogeny in Northern Tunisia. In doing so, it is the primary aim of this study to demonstrate how VR techniques may be applied to unravel basin subsidence/uplift history of structural domains and provide valuable insights into the kinematic evolution of sedimentary basins. VR measurements of both the onshore Pelagian Platform and the Tunisian Furrow in Northern Tunisia are used to impose constraints on the deformation history of a long‐lived structural feature in the studied region, namely the Zaghouan Fault. Previous work has shown that this fault was active as an extensional structure in Lower Jurassic to Aptian times, before subsequently being inverted during the Late Cretaceous Eocene Atlas I tectonic event and Upper Miocene Atlas II tectonic event. Quantifying and constraining this latter inversion stage, and shedding light on the roles of structural inheritance and the basin thermal history, are secondary aims of this study. The results of this study show that the Atlas II WNW‐ESE compressive event deformed both the Pelagian Platform and the Tunisian Furrow during Tortonian‐Messinian times. Maximum burial depth for the Pelagian Platform was reached during the Middle to Upper Miocene, i.e. prior to the Atlas II folding event. VR measurements indicate that the Cretaceous to Ypresian section of the Pelagian Platform was buried to a maximum burial depth of ~3 km, using a geothermal gradient of 30°C/km. Cretaceous rock samples VR values show that the hanging wall of the Zaghouan Fault was buried to a maximum depth of <2 km. This suggests that a vertical km‐scale throw along the Zaghouan Fault pre‐dated the Atlas II shortening, and also proves that the fault controlled the subsidence of the Pelagian Platform during the Oligo‐Miocene. Mean exhumation rates of the Pelagian Platform throughout the Messinian to Quaternary were in the order of 0.3 mm/year. However, when the additional effect of Tortonian‐Messinian folding is accounted for, exhumation rates could have reached 0.6-0.7 mm/year

    Structural and optical modeling of electro deposited CuInSe2 thin films

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    The ternary semiconductor CuInSe2 is one of the most advantageous materials for the manufacturing of thin film solar cells. In this study, CuInSe2 thin films were prepared at room temperature using the electrodepositing method. The as-prepared films were found to be amorphous. The CuInSe2 films were crystallized in a tubular resistive furnace, and characterized by means of the the X-ray diffraction (XRD) and UV-VIS-NIR spectroscopy techniques. The parameters to optimize are the temperature and duration of the annealing time, and the Cu/In ratio in the precursors

    Etude de la décontamination chimique par photolyse d'eaux environnementales : mise au point de méthodes analytiques pour des pesticides cibles

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    International audienceLes eaux environnementales peuvent ĂȘtre polluĂ©es par des contaminants chimiques et microbiologiques. Cette dĂ©gradation de la qualitĂ© des eaux peut reprĂ©senter un danger pour la santĂ© humaine, animale et les cultures agricoles. Les micropolluants chimiques peuvent ĂȘtre toxiques mĂȘme Ă  de faibles concentrations, de l'ordre du ”g/L ou ng/L. Parmi les micropolluants organiques, on retrouve les produits phytosanitaires tels que les pesticides, destinĂ©s Ă  protĂ©ger les vĂ©gĂ©taux contre certains organismes nuisibles. Ces molĂ©cules, potentiellement persistantes, peuvent ĂȘtre dispersĂ©es dans l'environnement, et contribuer Ă  la dĂ©gradation de la qualitĂ© des eaux environnementales par leurs effets secondaires nocifs et toxiques. Pour avoir une eau propre et saine, il est donc nĂ©cessaire de mettre en place un procĂ©dĂ© permettant de mieux contrĂŽler la contamination microbiologique et chimique des eaux en diminuant la quantitĂ© d'organismes pathogĂšnes et en dĂ©gradant les micropolluants tels que les produits phytosanitaires, ainsi que leurs mĂ©tabolites. Dans le cadre du projet FEDER COS-SĂ©sa, nous avons cherchĂ© Ă  mettre au point une mĂ©thode de dĂ©contamination chimique et microbiologique des eaux de process destinĂ©es au lavage de certaines productions agricoles. Ces eaux, utilisĂ©es en grand volume, doivent ĂȘtre recyclĂ©es dans le cadre d'une politique de dĂ©veloppement durable, et donc assainies. Notre objectif est d'Ă©tudier, par un procĂ©dĂ© pilote de photolyse, la dĂ©gradation de trois pesticides modĂšles : deux organophosphorĂ©s (le glyphosate et le malathion) et un organochlorĂ© (l'atrazine), potentiellement prĂ©sents dans des eaux environnementales. Afin de quantifier le niveau de concentration de ces molĂ©cules, ainsi que certains de leurs mĂ©tabolites aprĂšs un traitement photolytique continu, il est nĂ©cessaire de dĂ©velopper des mĂ©thodes d'analyse et de prĂ©-concentration particuliĂšrement sensibles. Ainsi, l'atrazine, le malathion et certains de leurs mĂ©tabolites peu polaires et thermostables sont analysĂ©s par GC-MS. En revanche, le glyphosate et l'AMPA (l'un de ses produits de dĂ©gradation) sont des molĂ©cules trĂšs polaires et sont sĂ©parĂ©s par HPLC fluorimĂ©trique aprĂšs une Ă©tape prĂ©alable de dĂ©rivation prĂ©-colonne au FMOC-Cl. Une attention particuliĂšre est portĂ©e sur les mĂ©thodes d'enrichissement de traces par SPE et l'optimisation de l'Ă©tape de dĂ©rivation, afin d'obtenir des sĂ©parations efficaces et sensibles. Les premiers rĂ©sultats concernant la dĂ©gradation de l'atrazine et du malathion dans des eaux dopĂ©es soumises aux UVc se sont avĂ©rĂ©s prometteurs. Les prochains travaux porteront sur l'Ă©tude de la dĂ©gradation du glyphosate par UVc, la cinĂ©tique de dĂ©gradation des trois pesticides cibles dans des eaux de process, et l'optimisation de leur exposition au pilote de photolyse

    Exploration of nuclear body-enhanced sumoylation reveals that PML represses 2-cell features of embryonic stem cells

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    International audienceMembrane-less organelles are condensates formed by phase separation whose functions often remain enigmatic. Upon oxidative stress, PML scaffolds Nuclear Bodies (NBs) to regulate senescence or metabolic adaptation. PML NBs recruit many partner proteins, but the actual biochemical mechanism underlying their pleiotropic functions remains elusive. Similarly, PML role in embryonic stem cell (ESC) and retro-element biology is unsettled. Here we demonstrate that PML is essential for oxidative stress-driven partner SUMO2/3 conjugation in mouse ESCs (mESCs) or leukemia, a process often followed by their poly-ubiquitination and degradation. Functionally, PML is required for stress responses in mESCs. Differential proteomics unravel the KAP1 complex as a PML NB-dependent SUMO2-target in arsenic-treated APL mice or mESCs. PML-driven KAP1 sumoylation enables activation of this key epigenetic repressor implicated in retro-element silencing. Accordingly, Pml −/− mESCs re-express transposable elements and display 2-Cell-Like features, the latter enforced by PML-controlled SUMO2-conjugation of DPPA2. Thus, PML orchestrates mESC state by coordinating SUMO2-conjugation of different transcriptional regulators, raising new hypotheses about PML roles in cancer
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