Formation and deformation of hyperextended rift systems: Insights from rift domain mapping in the Bay of Biscay-Pyrenees

International audienceThe Bay of Biscay and the Pyrenees correspond to a Lower Cretaceous rift system including both oceanic and hyperextended rift domains. The transition from preserved oceanic and rift domains in the West to their complete inversion in the East enables us to study the progressive reactivation of a hyperextended rift system. We use seismic interpretation, gravity inversion, and field mapping to identify and map former rift domains and their subsequent reactivation. We propose a new map and sections across the system illustrating the progressive integration of the rift domains into the orogen. This study aims to provide insights on the formation of hyperextended rift systems and discuss their role during reactivation. Two spatially and temporally distinct rift systems can be distinguished: the Bay of Biscay-Parentis and the Pyrenean-Basque-Cantabrian rifts. While the offshore Bay of Biscay represent a former mature oceanic domain, the fossil remnants of hyperextended domains preserved onshore in the Pyrenean-Cantabrian orogen record distributed extensional deformation partitioned between strongly segmented rift basins. Reactivation initiated in the exhumed mantle domain before it affected the hyperthinned domain. Both domains accommodated most of the shortening. The final architecture of the orogen is acquired once the conjugate necking domains became involved in collisional processes. The complex 3-D architecture of the initial rift system may partly explain the heterogeneous reactivation of the overall system. These results have important implications for the formation and reactivation of hyperextended rift systems and for the restoration of the Bay of Biscay and Pyrenean domain

Validation expérimentale d'outils de modélisation d'une pile à combustible de type PEM :

In this work, a global view of the phenomena occurring in a PEM fuel cell is given. An original methodology was developed in order to determine the main parameters : thermodynamics, kinetics and transport phenomena. The gas flow in bipolar plates was chracterised using experimental determination of residence time distributions and numerical simulations. Kinetics of both electrochemical reactions were analysed feeding the cell by diluted gases. In this part, the diffusion of reactants in the membrane electrodes assembly was taken into account. Finally, the relationship between humidity and electrical performance was investigated and the ohmic resistance of the cell was estimatedCette thèse tente d'apporter une vision globale des phénomènes mis en jeu lors du fonctionnement d'une pile à combustible de type PEM. Une méthodologie originale a été développée pour appréhender et mesurer les principaux paramètres thermodynamiques, cinétiques et des phénomènes de transport. La détermination expérimentale de la distribution des temps de séjour et la simulation numérique ont permis de caractériser l'écoulement dans les plaques bipolaires. La cinétique des deux demi-réactions électrochimiques a ensuite pu être analysée par des expériences ciblées de dilution des gaz réactifs, et en tenant compte de la diffusion dans l'assemblage membrane-électrodes. Enfin, l'influence de l'humidité sur les performances électriques, ainsi que l'estimation de la résistance ohmique, ont été abordée

Validation expérimentale d'outils de modélisation d'une pile à combustible de type PEM

Prix de thèse INPL 2006In this work, a global view of the phenomena occurring in a PEM fuel cell is given. An original methodology was developed in order to determine the main parameters : thermodynamics, kinetics and transport phenomena. The gas flow in bipolar plates was characterised using experimental determination of residence time distributions and numerical simulations. Kinetics of both electrochemical reactions were analysed feeding the cell by diluted gases. In this part, the diffusion of reactants in the membrane electrodes assembly was taken into account. Finally, the relationship between humidity and electrical performance was investigated and the ohmic resistance of the cell was estimated.Cette thèse tente d'apporter une vision globale des phénomènes mis en jeu lors du fonctionnement d'une pile à combustible de type PEM. Une méthodologie originale a été développée pour appréhender et mesurer les principaux paramètres thermodynamiques, cinétiques et des phénomènes de transport. La détermination expérimentale de la distribution des temps de séjour et la simulation numérique ont permis de caractériser l'écoulement dans les plaques bipolaires. La cinétique des deux demi-réactions électrochimiques a ensuite pu être analysée par des expériences ciblées de dilution des gaz réactifs, et en tenant compte de la diffusion dans l'assemblage membrane-électrodes. Enfin, l'influence de l'humidité sur les performances électriques, ainsi que l'estimation de la résistance ohmique, ont été abordées

Validation expérimentale d'outils de modélisation d'une pile à combustible de type PEM

Cette thèse tente d'apporter une vision globale des phénomènes mis en jeu lors du fonctionnement d'une pile à combustible de type PEM. Une méthodologie originale a été développée pour appréhender et mesurer les principaux paramètres thermodynamiques, cinétiques et des phénomènes de transport. La détermination expérimentale de la distribution des temps de séjour et la simulation numérique ont permis de caractériser l'écoulement dans les plaques bipolaires. La cinétique des deux demi-réactions électrochimiques a ensuite pu être analysée par des expériences ciblées de dilution des gaz réactifs, et en tenant compte de la diffusion dans l'assemblage membrane-électrodes. Enfin, l'influence de l'humidité sur les performances électriques, ainsi que l'estimation de la résistance ohmique, ont été abordéesIn this work, a global view of the phenomena occurring in a PEM fuel cell is given. An original methodology was developed in order to determine the main parameters : thermodynamics, kinetics and transport phenomena. The gas flow in bipolar plates was chracterised using experimental determination of residence time distributions and numerical simulations. Kinetics of both electrochemical reactions were analysed feeding the cell by diluted gases. In this part, the diffusion of reactants in the membrane electrodes assembly was taken into account. Finally, the relationship between humidity and electrical performance was investigated and the ohmic resistance of the cell was estimatedNANCY/VANDOEUVRE-INPL (545472102) / SudocSudocFranceF

Procédé A - enjeux et contraintes du laboratoire à l'échelle industrielle : une revue

International audienc

Bioconcentration of pharmaceuticals by the marine mussel M. galloprovincialis in laboratory controlled experiments.

International audienc

The marine mussel Mytilus galloprovincialis bioconcentrate and metabolize antidepressant pharmaceutical venlafaxine

International audienceA significant investment in research has been conducted to define exposures andpotential hazards of pharmaceuticals in freshwater and terrestrial ecosystems. Incontrast, comparatively few empirical studies have been conducted forpharmaceuticals that are likely to enter coastal and marine ecosystems[1,2]. Theantidepressant venlafaxine (VLF) and some of its metabolites were recently foundin mussels caged in a coastal site receiving treated wastewater[3]. In those marineorganisms, very scarce data is available on the accumulation and/or metabolisationof pharmaceuticals. Consequently, it appears hazardous to conclude on the originof those metabolites in mussels, which could include a bioaccumulation throughdirect exposure as well as a metabolism of VLF in mussels. The aim of the presentwork was to quantify the accumulation of VLF in the marine mussel Mytilusgalloprovincialis and to evaluate the possible metabolism in laboratory controlledexperiments. The accumulation of VLF was evaluated in the whole mussel tissuesafter 1, 3 and 7 days of semi-static exposure by water (10µg L-1day-1) followedby 1, 3 and 7 days of depuration. Under those conditions, VLF attained an averagetissue concentration of (n=3) 2146.3 ± 156.0 ng g-1 dry weight (d.w.) in sevendays. The kinetic bioconcentration factor (BCF) was 265 ± 19 L kg-1 d.w. Sevendays of depuration allowed a decrease of tissue concentration to 21 ± 1.0 ng g-1d.w. Four VLF metabolites were quantified in mussel tissues and excreted inwater. The kinetics of those metabolites in water confirmed the metabolism ofVLF by mussels. Complementary experiment conducted at 1, 10 and 100 µL L-1nominal concentration clearly confirmed that M. galloprovincialis metabolizeVLF, with the quantification of studied metabolites excepted the NNO-VLF.These results gave a first approach on the ability of mussel to metabolizepharmaceuticals. Together with bioaccumulation information, this study provideda first approach on the pharmacokinetics of a pharmaceutical in a wild marinespecies, underlining the need of further experiments to better understand howvenlafaxine modulate the receptors in mussels and how exposure to thisantidepressant affects physiological functions of invertebrates

In vivo exposure of marine mussels to venlafaxine: bioconcentration and metabolization

WOS:000674222500001Pharmaceuticals are present in natural waters, thus contributing to the general exposure of aquatic organisms, but few data are available on the accumulation of these substances in marine organisms. The present study evaluated the in vivo bioconcentration of an antidepressant-venlafaxine (VLF)-in marine mussels (Mytilus galloprovincialis) during 7 days of exposure at nominal 10 mu g/L concentration, followed by a 7-day depuration period. The bioconcentration factor (BCF) was 265 mL/g dry weight (dw). VLF accumulation reached an average tissue concentration of 2146 +/- 156 ng/g dw within 7 days, showing a first-order kinetics process. N-desmethylvenlafaxine (N-VLF) and O-desmethylvenlafaxine (O-VLF) metabolites were quantified in mussel tissues, whereas N,N-didesmethylvenlafaxine (NN-VLF) was only recorded as being detected. These three metabolites were also quantified in water, indicating an active metabolism and VLF excretion in Mediterranean mussels. Complementary experiments conducted at nominal concentrations of 1, 10, and 100 mu g/L for 7 days confirmed the VLF bioconcentration and metabolism and allowed us to quantify a supplementary metabolite, i.e., N,O-didesmethylvenlafaxine (NO-VLF), in mussel tissues. These results encourage further research on a more complete characterization of metabolism and on any disturbances linked to bioconcentration of VLF on bivalves

In vivo exposure of marine mussels to carbamazepine and 10-hydroxy-10,11-dihydro-carbamazepine: Bioconcentration and metabolization

International audienceAquatic organisms are exposed to pharmaceuticals present in natural waters, but few data are available on the accumulation of these substances in such organisms. The present study evaluated the in vivo bioconcentration of two anticonvulsants – carbamazepine (CBZ) and 10-hydroxy-10,11-dihydro-carbamazepine (10OH) – in marine mussels (Mytilus galloprovincialis) exposed to nominal 10 μg L− 1 concentrations for one week. The bioconcentration factors (BCFs) were 3.9 and 4.5 L kg− 1 dry weight (dw) for CBZ and 10OH, respectively. CBZ accumulation reached an average tissue concentration of 29.3 ± 4.8 ng g− 1 dw, and 10OH accumulated up to 40.9 ± 4.6 ng g− 1 dw in tissues within one week, showing first-order kinetics. BCF obtained with linear QSAR models correctly estimated the CBZ bioconcentration and overestimated the 10OH bioconcentration to some extent. The detection of two metabolites (carbamazepine-10,11-epoxide and acridine) among the five sought suggested an active metabolism for CBZ. In contrast, none of the 10OH metabolites were detected in mussels exposed to 10OH. CBZ showed higher accumulation in the digestive gland, where some relevant metabolites were detected, than in other studied tissues. The implication of those findings on field biomonitoring is discussed