Production et quelques propriétés de la bêta-apiosidase d'Aspergillus niger : action sur les précurseurs glycosidiques d'arôme du vin

National audienc

Bilan de dix années d’évaluation de lignées de maïs créées par sélection généalogique multicaractère combinant tolérance à la pyrale et aptitude à la combinaison pour le rendement

International audienceA multitrait pedigree breeding system including evaluation for European corn borer (Ostrinia nubilalis Hbn.) tolerance and other agronomic traits (yield, earliness, stalk lodging) was used for 16 years to create inbred lines from very different temperate germplasms. The ultimate evaluation of the 63 inbred lines was made in comparison with stable known references. The results allowed us to classify this material into three tolerance classes to the insect and demonstrated the efficacy of the method. High-yielding combining ability might be associated with earliness, lodging tolerance and good insect tolerance. The value of some early flint European materials and of Argentinian sources was discussed to improve European corn borer tolerance. (© Inra/Elsevier, Paris.)Pour associer la tolérance à la pyrale (O. nubilalis Hbn.) aux caractères agronomiques habituellement sélectionnés, des programmes de création et d’évaluation de lignées du maïs ont été développés par les laboratoires Inra du Maïs (Montpellier, Saint-Martin de Hinx, Bordeaux). En pépinière et dans les essais d’évaluation, la tolérance est exprimée par une note de dégâts à maturité corrigée pour les différences de précocité du matériel. L’utilisation de lignées étalons éprouvées et reconnues stables permet le classement de lignées en trois groupes de tolérance. La méthode de sélection généalogique repose sur une sélection simultanée par niveaux indépendants pour les deux caractères. Des essais de valeur hybride sur différents testeurs complètent les tris en valeur propre. Du matériel tolérant est obtenu dans les différentes sources utilisées. Toutefois, le matériel précoce européen et des sources argentines paraissent plus favorables à l’obtention de lignées tolérantes. Ces programmes ont permis l’obtention d’une soixantaine de lignées à forte aptitude à la combinaison pour le rendement et à bons niveaux de tolérance à la pyrale, avec des gains de précocité et de résistance à la verse. (© Inra/Elsevier, Paris.

Intercalation compounds of Mg-Al layered double hydroxides with dichlophenac: Different methods of preparation and physico-chemical characterization

International audience[2-(2,6-Dichloro-phenylamino)-phenyl]-acetic acid (DPAPAc) was intercalated between layers of Mg-Al hydrotalcites. Several methods of incorporation were applied: direct ion exchange of the layered double hydroxide (LDH) carbonates with the organic ions, direct synthesis by co-precipitation of metal nitrates and sodium DPAPAc, and reconstruction of the Mg-Al oxide solid solution. The LDH reconstruction method led to the highest degree of intercalation and gave rise to an enlargement of the interlayer space of about 6.7 Å, which was observed in the powder X-ray diffraction (PXRD) patterns. The new hybrid phase obtained by this method was partially intercalated, as the LDH-carbonate phase was still mainly present in the material. The characterization of the prepared samples was also achieved with X-ray photoelectron spectroscopy (XPS), which indicated changes in the environment of the elements on insertion of the organic anions. Finally, the collected data indicated that the method of reconstruction was the most effective route to the hybrid materials. © 2004 Elsevier B.V. All rights reserved

Production of B-apiosidase by Aspergillus niger. Partial purification, properties, and effect on terpenyl apiosylglucosides from grape

International audienc

New insights into micro/nanoscale combined probes (nanoAuger, uXPS) to characterize Ag/Au@SiO2 core–shell assemblies

This work has examined the elemental distribution and local morphology at the nanoscale of core@shell Ag/Au@SiO2 particles. The characterization of such complex metal/insulator materials becomes more efficient when using an initial cross-section method of preparation of the core@shell nanoparticles (ion milling cross polisher). The originality of this route of preparation allows one to obtain undamaged, well-defined and planar layers of cross-cut nano-objects. Once combined with high-resolution techniques of characterization (XPS, Auger and SEM), the process appears as a powerful way to minimize charging effects and enhance the outcoming electron signal (potentially affected by the topography of the material) during analysis. SEM experiments have unambiguously revealed the hollow-morphology of the metal core, while Auger spectroscopy observations showed chemical heterogeneity within the particles (as silver and gold are randomly found in the core ring). To our knowledge, this is the first time that Auger nano probe spectroscopy has been used and successfully optimized for the study of some complex metal/inorganic interfaces at such a high degree of resolution (?12 nm). Complementarily, XPS Au 4f and Ag 3d peaks were finally detected attesting the possibility of access to the whole chemistry of such nanostructured assemblies

Experimental measurements of CO2 solubility in a 1 mol/kgw CaCl2 solution at temperature from 323.15 to 423.15 K and pressure up to 20 Mpa

International audienc

Mesures expérimentales de la solubilité du CO2 dans des solutions salées à hautes températures et à hautes pressions

National audienc

On the catalytic properties of mixed oxides obtained from the Cu-Mg-Al LDH precursors in the process of hydrogenation of the cinnamaldehyde

International audienceCatalytic hydrogenation of cinnamaldehyde (CNA) was investigated over oxidic materials obtained by the calcination of Cu-Mg-Al layered double hydroxide (LDH) precursors. A series of precursors with different Cu/Mg ratios (with a constant M2+/Al3+ ratio) were prepared by coprecipitation (under low supersaturation) and heated under reductive atmosphere until 623K in order to avoid the formation of Cu-based spinels and to reduce the copper cations. The presence of Mg noticeably enhanced the selectivity of Cu-based catalysts with respect to the hydrogenation of the carbonyl group relative to the favoured hydrogenation of the C=C bond. Moreover, the self-condensation of hydrocinnamaldehyde (HCNA) and the cross-condensation of hydrocinnamaldehyde with cinnamaldehyde were also observed especially when the basic sites of LDH structures are preponderant over hydrogenation species. Finally, all that reaction from CNA are of great interest for getting information about: (i) basic sites involved in condensation of CNA and HCNA; and (ii) active species for selective hydrogenation of CNA to cinnamyl alcohol (CNOL) which seem in strong interaction with the first ones. © 2003 Elsevier B.V. All rights reserved