Poly(acrylic acid)-block-poly(vinyl alcohol) Anchored Maghemite Nanoparticles Designed for Multi-stimuli Triggered Drug Release

peer reviewe

Ti4+ to Ti3+ conversion of TiO2 uppermost layer by low-temperature vacuum annealing: interest for titanium biomedical applications.

Because of the Ti(3+) defects responsibility for dissociative adsorption of water onto TiO(2) surfaces and due to the hydroxyls influence on the biological behavior of titanium, controlling the Ti(3+) surface defects density by means of low-temperature vacuum annealing is proposed to improve the bone/implant interactions. Experiments have been carried out on Ti-6Al-4V alloys exhibiting a porous surface generated primarily by chemical treatment. XPS investigations have shown that low-temperature vacuum annealing can create a controlled number of Ti(3+) defects (up to 21% Ti(3+)/Ti(4+) at 573 K). High Ti(3+) defect concentration is linked to surface porosity. Such surfaces, exhibiting high hydrophilicity and microporosity, would confer to titanium biomaterials a great ability to interact with surrounding proteins and cells and hence would favor the bone anchorage of as-treated implants

Layered Li1+x(Ni0.425Mn0.425Co0.15)1–xO2 positive electrode materials for lithium-ion batteries

Layered Li1+x(Ni0..425Mn0..425Co0..15)1-xO2 materials (x = 0 and 0.12) were prepd. by copptn..

Structure And Nonlinear Optical Properties Of Sodium-Niobium Phosphate Glasses

The structural description of xNb2O5-(1 - x)(NaPO3) (0 ≤ x ≤ 0.40) glass network is reported through high-field (18.8 T) 17O and 93Nb nuclear magnetic resonance, O1s X-ray photoelectron spectroscopy and Raman spectroscopy. The different oxygen sites (POP, PONa, NbOP and NbONb) are resolved on the spectra, their relative proportion determined and compared to indirect calculations obtained from the decomposition of 31P NMR spectra. A good agreement is obtained, thus confirming the formation of the Nb(OP)6-y(ONb)y units with increasing y leading to the clusterization of NbO6 octahedra, mainly for x \u3e 0.2, which is related to the incomplete dissociation of Nb2O5 in the NaPO3 melt. The formation of these clusters is responsible for the large increase of the nonlinear optical properties, mainly due to the high polarizability of the Nb-O-Nb bond. © 2008 Elsevier B.V. All rights reserved

Synthèse de revêtements Ti3SiC2 sur monolithes SiC à partir de sels fondus

International audienceCoatings with composition close to Ti3SiC2 were obtained on SiC substrates from Ti and Si powders with the molten NaCl method. In this work, the growth of coatings by reaction in the salt between monolithic SiC substrates and titanium powder is obtained between 1000 and 1200°C. At 1000°C, a coating of 8 µm thickness is formed in 10 hours whereas a thin coating of 0.5 µm has been grown in 2 hours. A lack in silicon was first found in the coatings prepared at 1100 and 1200°C. For these temperatures, the addition of silicon powder in the melt had a favorable effect on the final composition, which is found very close to the composition of Ti3SiC2. The reaction mechanism implies the formation of TiCx layers in direct contact with the SiC substrate and the presence of more or less important quantities of Ti3SiC2 and Ti5Si3Cx in the upper layers.Des revêtements de composition proche de Ti3SiC2 ont été obtenus sur des substrats SiC à partir de poudres Ti et Si par la méthode du NaCl fondu. Dans ce travail, la croissance de revêtements par réaction dans le sel entre des substrats monolithiques SiC et de la poudre de titane est obtenue entre 1000 et 1200°C. A 1000°C, un revêtement de 8 µm d'épaisseur est formé en 10 heures alors qu'un revêtement fin de 0,5 µm a été développé en 2 heures. Un manque de silicium a d'abord été trouvé dans les revêtements préparés à 1100 et 1200°C. Pour ces températures, l'ajout de poudre de silicium dans le bain a un effet favorable sur la composition finale qui se retrouve très proche de la composition de Ti3SiC2. Le mécanisme réactionnel implique la formation de couches de TiCx en contact direct avec le substrat SiC et la présence de quantités plus ou moins importantes de Ti3SiC2 et Ti5Si3Cx dans les couches supérieures