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737 results on '"Devaux, J."'

104. Effects of K + Channel Blockers on Developing Rat Myelinated CNS Axons: Identification of Four Types of K + Channels

Author

Devaux, Jérôme, Devaux, J??r??me, Forni, Claude, Beeton, Christine, Barbaria, Jocelyne, B??raud, Evelyne, Gola, Maurice, Crest, Marcel, Jacquet, Guy, Institut des Neurosciences de Montpellier - Déficits sensoriels et moteurs (INM), and Institut National de la Santé et de la Recherche Médicale (INSERM)-Université de Montpellier (UM)

Subjects
medicine.medical_specialty, Potassium Channels, Physiology, Refractory period, [SDV]Life Sciences [q-bio], [SDV.NEU.NB]Life Sciences [q-bio]/Neurons and Cognition [q-bio.NC]/Neurobiology, Neurotoxins, Dendrotoxin, Kaliotoxin, Scorpion Venoms, Nerve Fibers, Myelinated, law.invention, 03 medical and health sciences, chemistry.chemical_compound, 0302 clinical medicine, law, Internal medicine, [SDV.BC.IC]Life Sciences [q-bio]/Cellular Biology/Cell Behavior [q-bio.CB], medicine, Potassium Channel Blockers, Animals, 4-Aminopyridine, Rats, Wistar, ComputingMilieux_MISCELLANEOUS, 030304 developmental biology, K channels, Elapid Venoms, 0303 health sciences, Chemistry, General Neuroscience, Age Factors, Tetraethylammonium, Optic Nerve, Tetraethylammonium chloride, Potassium channel, 3. Good health, Rats, Microscopy, Electron, Endocrinology, Animals, Newborn, [SDV.IMM.IA]Life Sciences [q-bio]/Immunology/Adaptive immunology, Optic nerve, [SDV.NEU]Life Sciences [q-bio]/Neurons and Cognition [q-bio.NC], Electron microscope, Neuroscience, 030217 neurology & neurosurgery
Abstract

Four blockers of voltage-gated potassium channels (Kv channels) were tested on the compound action potentials (CAPs) of rat optic nerves in an attempt to determine the regulation of Kv channel expression during the process of myelination. Before myelination occurred, 4-aminopyridine (4-AP) increased the amplitude, duration, and refractory period of the CAPs. On the basis of their pharmacological sensitivity, 4-AP-sensitive channels were divided in two groups, the one sensitive to kaliotoxin (KTX), dendrotoxin-I (DTX-I), and 4-AP, and the other sensitive only to 4-AP. In addition, tetraethylammonium chloride (TEA) applied alone broadened the CAPs. At the onset of myelination, DTX-I induced a more pronounced effect than KTX; this indicates that a fourth group of channels sensitive to 4-AP and DTX-I but insensitive to KTX had developed. The effects of KTX and DTX-I gradually disappeared during the period of myelination. Electron microscope findings showed that the disappearance of these effects was correlated with the ongoing process of myelination. This was confirmed by the fact that DTX-I and KTX enlarged the CAPs of demyelinated adult optic nerves. These results show that KTX- and DTX-sensitive channels are sequestrated in paranodal regions. During the process of myelination, KTX had less pronounced effects than DTX-I on demyelinated nerves, which suggests that the density of the KTX-sensitive channels decreased during this process. By contrast, 4-AP increased the amplitude, duration, and refractory period of the CAPs at all the ages tested and to a greater extent than KTX and DTX-I. The effects of TEA alone also gradually disappeared during this period. However, effects of TEA on CAPs were observed when this substance was applied after 4-AP to the adult optic nerve; this shows that TEA-sensitive channels are not masked by the myelin sheath. In conclusion, the process of myelination seems to play an important part in the regulation and setting of Kv channels in optic nerve axons.

Published
2002
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105. Benefits and limitations of adding hyperbranched polymers to dental resins.

Author

UCL - SSS/LDRI - Louvain Drug Research Institute, Dewaele, M, Leprince, Julian, Fallais, I, Devaux, J, Leloup, Gaëtane, UCL - SSS/LDRI - Louvain Drug Research Institute, Dewaele, M, Leprince, Julian, Fallais, I, Devaux, J, and Leloup, Gaëtane

Abstract

Volumetric shrinkage reduction is a constant challenge in the improvement of dental resins. The inclusion of hyperbranched polymers (HBPs) with modified functionalities (hydroxyl, propionate, and methacrylate) instead of conventional dimethacrylate monomers has the potential to reduce shrinkage, but can also affect other properties. The null hypothesis was that the addition of HBPs (from 5 to 40 mass%) to a 50/50 mass% Bis-GMA/TEGDMA mixture reduces shrinkage without affecting degree of conversion, elastic modulus, glass transition temperature, Wallace hardness (before/after ethanol storage), and viscosity. This hypothesis was rejected, since HBP incorporation significantly affected most properties either negatively or positively. When HBP amounts in the resin were increased, the following general trends were observed: Volumetric shrinkage decreased significantly (p < 0.0001), down to about one-third of the control value at 40% HBP; Wallace hardness (both before and after ethanol) and viscosity increased progressively, while elastic modulus showed a parabolic profile, with a maximum at 10% HBP; and finally, degree of conversion and glass transition temperature were relatively stable, regardless of the HBP content. These results indicate that HBPs with modified end groups might be interesting substitutes for Bis-GMA/TEGDMA.

Published
2012

106. Innovación para el desarrollo: Las estrategias y experiencias de papa andina

Author

Devaux, J. and Devaux, J.

Abstract

El presente artículo se basa en el libro Innovation for Development: The Papa Andina Experience (Devaux et al., 2011) compuesto por 25 artículos sobre las estrategias, enfoques y experiencias de la iniciativa regional conocida como Papa Andina. Tanto el libro como este artículo responden a las siguientes preguntas:• ¿Cómo vincular la investigación y el desarrollo para promover la innovación en favor de los pobres?• ¿Cómo fortalecer la capacidad y el desempeño de los sistemas de innovación en agricultura?En el marco del trabajo de Papa Andina se desarrollaron innovaciones comerciales – nuevos productos – así como innovaciones técnicas e institucionales en la cadena productiva de la papa. Se generaron diversos activos que pueden ser útiles no sólo para los participantes del proyecto, sino también para otros interesados en vincular la investigación con los procesos de desarrollo y fortalecer los sistemas de innovación. En este artículo se resume el trabajo realizado en Bolivia, Ecuador y Perú para estimular la innovación a nivel del sector papa en la región andina. Se analizan enfoques desarrollados y empleados para vincular a los pequeños productores de papa con los mercados de alto valor, así como enfoques complementarios para desarrollar y organizar cadenas productivas, plataformas de actores, generar responsabilidad social empresarial, aprendizaje social, intercambio de conocimientos, incidencia pública y de políticas e inclusión de los conceptos de empoderamiento y género en los procesos de innovación. Finalmente, se muestran los resultados que incluyen nuevos productos y acceso a nichos de mercado, así como innovaciones tecnológicas e institucionales en la producción y comercialización de la papa. Papa Andina ha mejorado la percepción pública de este producto como alimento saludable, generador de ingresos, recurso para el desarrollo y fuente de orgullo cultural. No sólo pequeños productores y productoras de papa –sino muchos otros actores que participan en la pro

Published
2012

107. Primary productivity in the recently flooded 'Sep Reservoir' (Puy-de-Dôme, France)

Author

Tadonléké, R. D., Télesphore Sime-Ngando, Amblard, C., Sargos, D., Devaux, J., Laboratoire Microorganismes : Génome et Environnement (LMGE), Université Blaise Pascal - Clermont-Ferrand 2 (UBP)-Université d'Auvergne - Clermont-Ferrand I (UdA)-Centre National de la Recherche Scientifique (CNRS), Sime-Ngando, Télesphore, and Université Blaise Pascal - Clermont-Ferrand 2 (UBP)-Centre National de la Recherche Scientifique (CNRS)-Université d'Auvergne - Clermont-Ferrand I (UdA)

Subjects
Species succession, Seasonal variation, Central Massif, Freshwater environment, Plant community, Environmental factor, [SDE.BE] Environmental Sciences/Biodiversity and Ecology, Europe, Phytoplankton, Primary productivity, Biomass, Impoundment, France, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, Nutrient
Abstract

International audience; Seasonal variations in phytoplankton biomass and production were studied in 1996 and 1997 in the newly flooded (1995) Sep Reservoir (France) in relation to various physico-chemical environmental factors. No trophic upsurge occurred in the reservoir as has been found in most of the newly flooded reservoirs. Phytoplankton composition changed drastically from 1996 to 1997, the latter year being characterized by a rarity of diatoms. Areal euphotic chlorophyll a concentration and phytoplankton carbon biomass were typical of mesotrophic lakes in 1996 and of somewhat oligotrophic environments in 1997. In contrast, the primary production (PP) rates were similar in both years, indicating a change in the factors controlling phytoplankton populations from 1996 to 1997. The low PP (compared with the algal biomass present) in 1996 seemed to be related to the instability of the water column and the Zmix:Zeu ratio, whose negative effects on the phytoplankton community were apparently more pronounced in 1996 than in 1997. Orthophosphate concentrations, and their contribution to total phosphorus, remained low in 1996 but increased with time in 1997. The temporal losses of orthophosphates from June to September 1996 accounted for only 42% of the measured PP, indicating that PP in 1996 was also strongly affected by P availability and probably took place due to other P sources such as regenerated nutrients.

Published
2000

108. High irradiance curing and anomalies of exposure reciprocity law in resin-based materials.

Author

UCL - SST/IMCN/BSMA - Bio and soft matter, Hadis, M, Leprince, Julian, Shortall, A C, Devaux, J, Leloup, Gaëtane, Palin, W M, UCL - SST/IMCN/BSMA - Bio and soft matter, Hadis, M, Leprince, Julian, Shortall, A C, Devaux, J, Leloup, Gaëtane, and Palin, W M

Abstract

The aim of this work was to investigate the effect of high irradiance curing on resultant degree of conversion of 'flowable' resin composites and their counterpart higher viscosity paste materials.

Published
2011

109. Irradiation modes' impact on radical entrapment in photoactive resins.

Author

Leprince JG, Lamblin G, Devaux J, Dewaele M, Mestdagh M, Palin WM, Gallez B, Leloup G, Leprince, J G, Lamblin, G, Devaux, J, Dewaele, M, Mestdagh, M, Palin, W M, Gallez, B, and Leloup, G

Abstract

Different irradiation protocols are proposed to polymerize dental resins, and discordances remain concerning their impact on the material. To improve this knowledge, we studied entrapment of free radicals in unfilled Bis-GMA/TEGDMA (50:50 wt%) resin after light cure. The tested hypothesis was that various irradiation parameters (curing time, irradiance, and radiant exposure) and different irradiation modes (continuous and pulse-delay) led to different amounts of trapped free radicals. The analysis of cured samples (n = 3) by electron paramagnetic resonance (EPR) revealed that the concentrations of trapped free radicals significantly differed according to the curing protocol. When continuous modes with similar radiant exposure were compared, higher concentrations of trapped free radicals were measured for longer times with lower irradiance. Concerning pulse modes, the delay had no influence on trapped radical concentration. These results give new insights into the understanding of the photopolymerization process and highlight the relevance of using EPR when studying polymerization of dimethacrylate-based materials. [ABSTRACT FROM AUTHOR]

Published
2010
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113. Electron spin resonance, a useful analytical technique for studying the kinetic decay of free radicals trapped in dental resin

Author

UCL - SSS/LDRI - Louvain Drug Research Institute, Lamblin, G., Truffier-Boutry, D., Demoustier, Sophie, Devaux, J., Biebuyck, J.-J., Debatty-Mestdagh, M., Leloup, Gaëtane, UCL - SSS/LDRI - Louvain Drug Research Institute, Lamblin, G., Truffier-Boutry, D., Demoustier, Sophie, Devaux, J., Biebuyck, J.-J., Debatty-Mestdagh, M., and Leloup, Gaëtane

Published
2007

130. Etude de la préparation des poissons par échosondage lors d'un cycle de 48 heures. Lac de Villerest, France

Author

Desmolles, F., Gerdeaux, Daniel, Guillard, Jean, Devaux, J., ProdInra, Migration, Centre Alpin de Recherche sur les Réseaux Trophiques et Ecosystèmes Limniques (CARRTEL), and Institut National de la Recherche Agronomique (INRA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])

Subjects
[SDV] Life Sciences [q-bio], [SDV]Life Sciences [q-bio], ComputingMilieux_MISCELLANEOUS
Abstract

National audience

Published
1993

133. Sarcoïdose cardiaque: étude rétrospective de 102 cas

Author

Chapelon-Abric, C., primary, Sene, D., additional, Cluzel, P., additional, de Zuttere, D., additional, Devaux, J.-Y., additional, Wechsler, B., additional, Du Boutin, Z., additional, Costedoat-Chalumeau, N., additional, Limal, N., additional, Haroche, J., additional, Trad, S., additional, and Piette, J.-C., additional

Published
2007
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