Preparation of multifunctional hollow fiber nanofiltration membranes by dynamic assembly of weak polyelectrolyte multilayers

In this work, we investigate the effect of preparation conditions for dynamic layer-by-layer (LbL) coating, to prepare multifunctional hollow fiber nanofiltration (NF) membranes. Dynamic coating was performed at constant pressure and at variable cross flow speeds. In this way, polyelectrolyte multilayers (PEMs) were formed of the weak polyelectrolytes poly(acrylic acid) (PAA) and poly(allylamine hydrochloride) (PAH), on a negatively charged polyethersulfone ultrafiltration (UF) support. The resulting membrane performance was investigated and compared to membranes prepared by different methods (dip coating and dead end filtration), and it was found to be comparable. It was shown that PAH/PAA multilayers can be fabricated reproducibly and homogenously using optimised dynamic LbL deposition conditions on single fiber module (surface area of 6.2 cm2) as well as on a module of 15 fibers (surface area of 67 cm2). Moreover, the approach of dynamic coating could be easily up scaled to coat existing UF modules. The prepared membranes reject the solutes on the basis of size exclusion and Donnan exclusion, retaining small organic solutes and divalent ions. Membranes terminated with PAA exhibit a low fouling tendency compared to membranes terminated with PAH and compared to the UF support membrane. Moreover, if severe membrane fouling would occur after prolonged use, the PEM coating, including any attached foulants can be removed by rinsing with a solution that combines a low pH and a high salinity (pH 3, 3 M). The surface of bovine serum albumin (BSA) fouled membranes were successfully cleaned at least twice, after which a new PEM coating could be re-applied by active coating

Serum proteins electrophoresis changes in dogs infected with Dirofilaria immitis, with Dirofi/aria repens and with both of them

L’électrophorèse des protéines sériques sur acétate de cellulose (migration de 4 heures, bande et courbe de même longueur) a été réalisée sur 4 groupes de chiens: l.Non infestés. 2. Infestés par Dirofilaria immitis. 3. Infestés par Dirofilaria repens. 4. Infestation mixte. L’étude statistique des résultats indique une augmentation significative des globulines gamma pour les groupes 2 et 4.Serum proteins electrophoresis on cellulose ace tat (four hours migration, same length for bands and curves) was carried out on four groups of dogs. Group 1 : not infected, group 2 : only infected with Dirofilaria immitis, group 3 : only infected with Dirofilaria repens and group 4 : infected with both of them. A statistic study shows that the serum globulins level rises to a significative value in groups two and four

Copolymère à blocs amphiphile et son utilisation pour la fabrication de membranes polymères et de filtration

L'invention concerne un copolymère à blocs amphiphile comportant au moins un premier bloc hydrophile susceptible d'être obtenu à partir de monomères d'acrylate de n-butyle et de méthacrylate d'hydroxyéthyle, et un deuxième bloc hydrophobe susceptible d'être obtenu à partir d'un monomère de méthacrylate de méthyle. Ce copolymère s'avère particulièrement avantageux pour une utilisation en tant qu'additif pour la fabrication d'une membrane polymère de filtration, notamment à base de PVDF, en particulier par un procédé d'inversion de phase

Homopolymérisation et copolymérisation de macromonomères de polystyrène par catalyse de métaux de transition

STRASBOURG-Sc. et Techniques (674822102) / SudocSudocFranceF

La besnoitiose bovine en Ariège

TOULOUSE3-BU Santé-Centrale (315552105) / SudocTOULOUSE-EN Vétérinaire (315552301) / SudocSudocFranceF

CROTALUS DURISSUS OU SERPENT A PLUMES (BIOLOGIE ET SYMBOLIQUE AU SEIN DES CIVILISATIONS PRECOLOMBIENNES)

TOULOUSE-EN Vétérinaire (315552301) / SudocSudocFranceF

Correlation of Cassignol-Gillot K-Ar dating and paleomagnetism: chronology of the Mid-Miocene High Börzsöny lava dome complex, Hungary

International audienceThe Mid-Miocene volcanism of the Börzsöny Mountains, North Hungary, has been re-studied by correlating new New Cassignol-Gillot K-Ar dating with paleomagnetism. The volcanism developed in three stages. Thefirst-stage activity occurred in a shallow marine environment, producing mostly dacitic volcaniclastics (originating from small-scale ignimbrite eruptions and lava domes). The second stage, not studied here, was characterised by scattered andesitic lava domes. Importantly, during this stage, a ca. 30o CCW rotation occurred. During the third stage, a moderately explosive, andesitic / basaltic andesitic subaerial lava dome complex, called High Börzsöny, grew up, producing lava flows and block-and-ash flows, and showing no rotation. The regular-shaped dome has developed a central, enlarged erosion caldera, clearly recognisable in the landscape despite long-term denudation and intense tectonic faulting over the mountains.New Cassignol-Gillot K-Ar dating obtained on biotite from dacitic pumiceous lapilli tuff of the first stage yielded an age of 15.68±0.22 Ma (1σ) , which largely fits to the magnetostratigraphically established age (≥16 Ma) of the first stage (normal polarity, 30o CCW rotation.) Dating effort focussed on the third stage, namely the groundmass of the rocks of the andesitic High Börzsöny. The obtained ages, ranging between 14.99±0.23 to 14.27±0.20 Ma, are in agreement with their stratigraphic position from bottom (the internal part of the High Börzsöny erosion caldera) to top (flank lava flows), and are somewhat (ca. 0.5 Ma) older than previous conventional K-Ar measurements (cf. Karátson et al. 2000). Moreover, these ages constrain the activity of the High Börzsöny, which, subsequent to a reverse polarity zone (of the second stage), was active within one or two normal polarity zones ending >14 Ma. The time frame for the High Börzsöny dome complex (0.73±0.31 My) fits to other well-known domes worldwide (e.g. Montagne Pelée, 550 ky). Whereas uncertainties allow a shorter life time as well (<0.5 My), a longer duration is not likely.Karátson, D., Márton, E., Harangi, Sz., Józsa, S., Balogh, K., Pécskay, Z., Kovácsvölgyi, S., Szakmány, Gy., Dulai, A. 2000: Volcanic evolution and stratigraphy of the Miocene Börzsöny Mountains, Hungary: anintegrated study. Geologica Carpathica, 51/1, p. 325-34

Correlation of Cassignol-Gillot K-Ar dating and paleomagnetism: chronology of the Mid-Miocene High Börzsöny lava dome complex, Hungary

International audienceThe Mid-Miocene volcanism of the Börzsöny Mountains, North Hungary, has been re-studied by correlating new New Cassignol-Gillot K-Ar dating with paleomagnetism. The volcanism developed in three stages. Thefirst-stage activity occurred in a shallow marine environment, producing mostly dacitic volcaniclastics (originating from small-scale ignimbrite eruptions and lava domes). The second stage, not studied here, was characterised by scattered andesitic lava domes. Importantly, during this stage, a ca. 30o CCW rotation occurred. During the third stage, a moderately explosive, andesitic / basaltic andesitic subaerial lava dome complex, called High Börzsöny, grew up, producing lava flows and block-and-ash flows, and showing no rotation. The regular-shaped dome has developed a central, enlarged erosion caldera, clearly recognisable in the landscape despite long-term denudation and intense tectonic faulting over the mountains.New Cassignol-Gillot K-Ar dating obtained on biotite from dacitic pumiceous lapilli tuff of the first stage yielded an age of 15.68±0.22 Ma (1σ) , which largely fits to the magnetostratigraphically established age (≥16 Ma) of the first stage (normal polarity, 30o CCW rotation.) Dating effort focussed on the third stage, namely the groundmass of the rocks of the andesitic High Börzsöny. The obtained ages, ranging between 14.99±0.23 to 14.27±0.20 Ma, are in agreement with their stratigraphic position from bottom (the internal part of the High Börzsöny erosion caldera) to top (flank lava flows), and are somewhat (ca. 0.5 Ma) older than previous conventional K-Ar measurements (cf. Karátson et al. 2000). Moreover, these ages constrain the activity of the High Börzsöny, which, subsequent to a reverse polarity zone (of the second stage), was active within one or two normal polarity zones ending >14 Ma. The time frame for the High Börzsöny dome complex (0.73±0.31 My) fits to other well-known domes worldwide (e.g. Montagne Pelée, 550 ky). Whereas uncertainties allow a shorter life time as well (<0.5 My), a longer duration is not likely.Karátson, D., Márton, E., Harangi, Sz., Józsa, S., Balogh, K., Pécskay, Z., Kovácsvölgyi, S., Szakmány, Gy., Dulai, A. 2000: Volcanic evolution and stratigraphy of the Miocene Börzsöny Mountains, Hungary: anintegrated study. Geologica Carpathica, 51/1, p. 325-34

New age constraints on the timing of volcanism in central Afar, in the presence of propagating rifts

International audienceWe investigate the relationship between rift propagation and volcanism in the Afar Depression in the last 4 Myr. Potassium-argon and thermoluminescence dating allow detailed reconstruction of the temporal evolution of volcanism. Volcanic activity is almost continuous since 3.5 Ma, with intervals characterized by more intense activity, especially around 2 Ma. Spatial distribution of ages reveals that Stratoid Series volcanism migrated northward along a 200-km trend between 3 and 1 Ma, at about 10 cm/yr, linked to northward propagation of the Gulf of Aden Ridge, after it had cut across the Danakil horst at 4 Ma. Our work underlines the role of rhyolitic volcanism in initiation of rifting. Acid volcanoes, initially formed near the axes of extensional zones, have been subsequently dissected and are presently located on both sides of active rift segments. These lavas were the first to be erupted in areas of low extensional strain and were followed by basaltic lavas as extension increased. Differentiated volcanoes acted as zones of local weakness and guided localization of fractures, then leading to fissural magmatism. This regional-scale, composite style of rifting, including volcanic and tectonic components, can be compared to the large-scale continental breakup process itself. Deformation occurs through propagation of faults and fissures under a regional stress field. These become localized because of weakening of the crust (or lithosphere) due to emplacement of magmas, under the influence of a plume in the large-scale case, or of silicic centers linked to magma chambers in the regional-scale case