Surface Deposition and Phase Behavior of Oppositely Charged Polyion–Surfactant Ion Complexes. Delivery of Silicone Oil Emulsions to Hydrophobic and Hydrophilic Surfaces

The adsorption from mixed polyelectrolyte-surfactant solutions at hydrophobized silica surfaces was investigated by in situ null-ellipsometry, and compared to similar measurements for hydrophilic silica surfaces. Three synthetic cationic copolymers of varying hydrophobicity and one cationic hydroxyethyl cellulose were compared in mixtures with the anionic surfactant sodium dodecylsulfate (SDS) in the absence or presence of a dilute silicone oil emulsion. The adsorption behavior was mapped while stepwise increasing the concentration of SDS to a polyelectrolyte solution of constant concentration. The effect on the deposition of dilution of the bulk solution in contact with the surface was also investigated by gradual replacement of the bulk solution with 1 mM aqueous NaCl. An adsorbed layer remained after complete exchange of the polyelectrolyte/surfactant solution for aqueous NaCl. In most cases, there was a codeposition of silicone oil droplets, if such droplets were present in the formulation before dilution. The overall features of the deposition were similar at hydrophobic and hydrophilic surfaces, but there were also notable differences. SDS molecules adsorbed selectively at the hydrophobized silica surface, but not at the hydrophilic silica, which influenced the coadsorption of the cationic polymers. The largest amount of deposited material after dilution was found for hydrophilic silica and for the least-hydrophobic cationic polymers. For the least-hydrophobic polyions, no significant codeposition of silicone oil was detected at hydrophobized silica after dilution if the initial SDS concentration was high

Aspects pratiques de la culture de Pleurotus sp.

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Aspects pratiques de la culture de Pleurotus sp.

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Use of an Immunocapture-Polymerase Chain Reaction Procedure for the Detection of Grapevine Virus A in Kober Stem Grooving-Infected Grapevines

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Nomades et commandants : administration et sociétés nomades dans l'ancienne A.O.F.

Trente ans ont passé depuis la fin de la période coloniale en Afrique francophone : presque la moitié de sa durée totale sur la rive saharienne de l'ancienne Afrique occidentale française. Trente ans : bien peu dans l'histoire , assez pour que soit arrivé le temps du regard serein, presque trop tard si l'on veut encore entendre les témoins dont les voix vont s'éteindre les unes après les autres. C'est ce qu'ont pensé un chercheur, Edmond Bernus, deux universitaires Pierre Boilley et Jean-Louis Triaud qui ont consacré études et recherches aux populations du Sahara et du Sahel et un ancien administrateur de la France d'Outre-Mer, Jean Clauzel, qui a servi où se côtoyaient Maures et Touaregs. Tous quatre ont organisé une rencontre à plusieurs voix entre anciens colonisés, de ceux que l'administration appelaient "Nomades", et anciens colonisateurs, de ceux, civils et militaires, que leurs administrés appelaient "Commandants", la troisième voix étant celle des historiens et sociologues, africains et français. Ce dialogue décrit, raconte et tente d'analyser ce que furent, de la fin de la Première Guerre Mondiale à la colonisation, les rapports entre "Nomades et Commandants" avant le Polisario et la "Révolte des hommes bleus". (Résumé d'auteur

Inheritance of phenological traits in apricot progenies

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