35 research outputs found

    Jouer avec les dieux (notes sur la matière mythologique chez Vélasquez)

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    International audienceDans les tableaux mythologiques de Vélasquez, il est souvent mis l'accent sur une dimension burlesque qui ne rend peut-être pas tout à fait compte de la complexité et des nuances du dispositif mis en place par le peintre ; c'est ainsi que des œuvres comme " Le triomphe de Bacchus " ou " Mars ", trop souvent ramenées à une simple moquerie, révèlent des lignes de sens moins immédiates

    Le nain, le bouffon, l'artiste : le pouvoir d'en bas dans la peinture de Vélasquez

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    International audienceLes nains et les bouffons occupent une place particulière dans l'œuvre de Vélasquez ; en leur rendant humanité et dignité, le peintre suscite à leur égard un regard qui diverge de celui que la société du XVIIème siècle portait globalement sur eux. Dans la perspective de cette mise en valeur de figures du bas, socialement méprisées, ils présentent plus d'un point commun avec celle de l'artiste lui-mêm

    Les espaces utopiques de la peinture de Salvador Dalí

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    International audienceLa nature des espaces construits dans les tableaux de Salvador Dalí, que ceux-ci s'élaborent dans la perspective surréaliste (période principalement évoquée dans cet article), ou dans celle de la "mystique nucléaire" ultérieure, invite à s'interroger sur le degré d'existence ou de non-existence de ces espaces pour celui qui en est le spectateur et, par là même, sur la capacité de ce dernier à les habiter ou non de son regard

    A propos des yeux et du corps dans quelques tableaux de Vélasquez

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    Les yeux occupent une place privilégiée dans les tableaux de Vélasquez, car ils disent plus que la simple attestation présente d'une existence passée ; ils proposent une singulière articulation de l'être et des apparences qui l'entourent, et finissent par suggérer tout un rapport de l'homme aux mondes matériel et spirituel, un rapport si profond qu'il dépasse le cadre strict de l'époque baroque

    Understanding the Phase Behavior of Tetrahydrofuran + Carbon Dioxide, + Methane, and + Water Binary Mixtures from the SAFT-VR Approach

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    The high-pressure phase diagrams of the tetrahydrofuran(1) + carbon dioxide(2), + methane(2), and + water(2) mixtures are examined using the SAFT-VR approach. Carbon dioxide molecule is modeled as two spherical segments tangentially bonded, water is modeled as a spherical segment with four associating sites to represent the hydrogen bonding, methane is represented as an isolated sphere, and tetrahydrofuran is represented as a chain of m tangentially bonded spherical segments. Dispersive interactions are modeled using the square-well intermolecular potential. In addition, two different molecular model mixtures are developed to take into account the subtle balance between water–tetrahydrofuran hydrogen-bonding interactions. The polar and quadrupolar interactions present in water, tetrahydrofuran, and carbon dioxide are treated in an effective way via square-well potentials of variable range. The optimized intermolecular parameters are taken from the works of Giner et al. (Fluid Phase Equil. 2007, 255, 200), Galindo and Blas (J. Phys. Chem. B 2002, 106, 4503), Patel et al. (Ind. Eng. Chem. Res. 2003, 42, 3809), and Clark et al. (Mol. Phys. 2006, 104, 3561) for tetrahydrofuran, carbon dioxide, methane, and water, respectively. The phase diagrams of the binary mixtures exhibit different types of phase behavior according to the classification of van Konynenburg and Scott, ranging from types I, III, and VI phase behavior for the tetrahydrofuran(1) + carbon dioxide(2), + methane(2), and + water(2) binary mixtures, respectively. This last type is characterized by the presence of a Bancroft point, positive azeotropy, and the so-called closed-loop curves that represent regions of liquid–liquid immiscibility in the phase diagram. The system exhibits lower critical solution temperatures (LCSTs), which denote the lower limit of immiscibility together with upper critical solution temperatures (UCSTs). This behavior is explained in terms of competition between the incompatibility with the alkyl parts of the tetrahydrofuran ring chain and the hydrogen bonding between water and the ether group. A minimum number of unlike interaction parameters are fitted to give the optimal representation of the most representative features of the binary phase diagrams. In the particular case of tetrahydrofuran(1) + water(2), two sets of intermolecular potential model parameters are proposed to describe accurately either the hypercritical point associated with the closed-loop liquid–liquid immiscibility region or the location of the mixture lower- and upper-critical end-points. The theory is not only able to predict the type of phase behavior of each mixture, but also provides a reasonably good description of the global phase behavior whenever experimental data are availabl

    Molecular dynamics and thermodynamical modelling using SAFT-VR to predict hydrate phase equilibria : application to CO2 hydrates

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    This work was dedicated to the prediction of the three phase coexistence line (CO2 hydrate–liquid H2Oliquid/vapour CO2) for the H2O+CO2 binary mixture by using (i) molecular dynamics simulations, and (ii) the well known van der Waals-Platteeuw (vdWP) model combined with the SAFT-VR equation of state. Molecular dynamics simulations have been performed using the simulation package GROMACS. The temperature at which the three phases are in equilibrium was determined for different pressures, by using direct coexistence simulations. Carbon dioxide was modelled as a linear-rigid chain molecule with three chemical units, the well-known version TraPPE molecular model. The TIP4P/Ice model was used for water. To perform the thermodynamical modelling, the SAFT-VR EOS was incorporated in the vdWP framework. The values of the cell model parameters were regressed and discussed together with the influence of some assumptions of the vdWP model. Since SAFT-VR can describe most of fluids involved in hydrate modelling (inhibitors, salts…), this study is a first step in the description of hydrate forming conditions of more complex systems. Finally, the three-phase coexistence temperatures obtained with both simulations and theory at different pressures were compared with experimental result

    Understanding the Phase Behavior of Tetrahydrofuran + Carbon Dioxide, + Methane, and + Water Binary Mixtures from the SAFT-VR Approach

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    The high-pressure phase diagrams of the tetrahydrofuran(1) + carbon dioxide(2), + methane(2), and + water(2) mixtures are examined using the SAFT-VR approach. Carbon dioxide molecule is modeled as two spherical segments tangentially bonded, water is modeled as a spherical segment with four associating sites to represent the hydrogen bonding, methane is represented as an isolated sphere, and tetrahydrofuran is represented as a chain of m tangentially bonded spherical segments. Dispersive interactions are modeled using the square-well intermolecular potential. In addition, two different molecular model mixtures are developed to take into account the subtle balance between water−tetrahydrofuran hydrogen-bonding interactions. The polar and quadrupolar interactions present in water, tetrahydrofuran, and carbon dioxide are treated in an effective way via square-well potentials of variable range. The optimized intermolecular parameters are taken from the works of Giner et al. (Fluid Phase Equil. 2007, 255, 200), Galindo and Blas (J. Phys. Chem. B 2002, 106, 4503), Patel et al (Ind. Eng. Chem. Res. 2003, 42, 3809), and Clark et al. (Mol. Phys. 2006, 104, 3561) for tetrahydrofuran, carbon dioxide, methane, and water, respectively. The phase diagrams of the binary mixtures exhibit different types of phase behavior according to the classification of van Konynenburg and Scott, ranging from types I, III, and VI phase behavior for the tetrahydrofuran(1) + carbon dioxide(2), + methane(2), and + water(2) binary mixtures, respectively. This last type is characterized by the presence of a Bancroft point, positive azeotropy, and the so-called closed-loop curves that represent regions of liquid−liquid immiscibility in the phase diagram. The system exhibits lower critical solution temperatures (LCSTs), which denote the lower limit of immiscibility together with upper critical solution temperatures (UCSTs). This behavior is explained in terms of competition between the incompatibility with the alkyl parts of the tetrahydrofuran ring chain and the hydrogen bonding between water and the ether group. A minimum number of unlike interaction parameters are fitted to give the optimal representation of the most representative features of the binary phase diagrams. In the particular case of tetrahydrofuran(1) + water(2), two sets of intermolecular potential model parameters are proposed to describe accurately either the hypercritical point associated with the closed-loop liquid−liquid immiscibility region or the location of the mixture lower- and upper-critical end-points. The theory is not only able to predict the type of phase behavior of each mixture, but also provides a reasonably good description of the global phase behavior whenever experimental data are available.We acknowledge Ministerio de Economía y Competitividad of Spain for financial support from Projects FIS2012-33621 and FIS2015-68910-P (M.M.P. and J.M.M.) and FIS2013-46920- C2-1-P (F.J.B. and J.A.), both cofinanced with EU Feder funds. J.M.M. acknowledges Xunta de Galicia for a Postdoctoral Grant (ED481B2014/117-0). The French CARNOT Institute ISIFoR is also acknowledged for the funds provided through the THEMYS Project (novel approaches in thermodynamical modelling and molecular simulation for the study of gas hydrates and their applications). Further financial support from Universidad de Huelva and Junta de Andalucía is also acknowledged

    Pharmacogenetic assessment of toxicity and outcome in patients with metastatic colorectal cancer treated with LV5FU2, FOLFOX, and FOLFIRI: FFCD 2000-05

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    L’objectif de ce travail était la recherche de biomarqueurs moléculaires prédictifs de la tolérance et de l’efficacité des chimio– thérapies utilisées dans le colorectal (CCR) métastatique. Nous avons effectué le génotypage de 20 polymorphismes présents au sein de 9 gènes connus ou suspectés d’être impliqués dans la voie du 5FU, de l’oxaliplatine, ou de l’irinotécan, à partir de l’ADN extrait du sang de 346 patients traités dans le cadre d’un essai de phase III. Cet essai comparait une chimiothérapie séquentielle par 5FU (schéma LV5FU2) suivie d’une association 5FU plus oxali– platine (schéma FOLFOX) à une chimiothérapie combinée de type FOLFOX d’emblée en première ligne de traitement. Nous avons trouvé un risque de toxicité hématologique sévère sous FOLFOX significativement augmenté chez les patients porteurs de l’allèle ERCC2-K751QC. La présence de l’allèle TS-5’UTR3RG du gène de la thymidylate synthase était associée à un taux de réponse significativement plus élevé sous LV5FU2. Le taux de réponse au FOLFOX en 2e ligne était significativement supérieur chez les patients porteurs de l’allèle ERCC1-IVS3+74G, et chez ceux ayant au moins un allèle de GSTT1 présent. L’analyse prédictive a montré un effet dépendant du traitement de certains polymorphismes. En effet, une survie sans progression significativement allongée par l’ajout de l’oxaliplatine en 1re ligne a été observée uniquement chez les patients ayant un génotype TS-5’UTR2R/2R ou 2R/3R, suggérant l’absence de bénéfice d’une bithérapie par FOLFOX d’emblée en première ligne chez les patients TS-5’UTR3R/3R. Ces résultats montrent que l’étude des polymorphismes constitutionnels permettent de prédire non seulement la toxicité mais aussi l’efficacité des chimiothérapies antitumorales du cancer colorectal, et ainsi (sous réserve d’une validation sur une population indépendante) d’orienter la stratégie thérapeutique à l’échelle de l’individu
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