University of Bordeaux

About: University of Bordeaux is a education organization based out in Bordeaux, France. It is known for research contribution in the topics: Population & Laser. The organization has 28811 authors who have published 55536 publications receiving 1619635 citations. The organization is also known as: UB.

SiC filament/titanium matrix composites regarded as model composites

Abstract: It is generally accepted that silicon carbide CVD-filaments are more suitable than the related boron filaments for reinforcing titanium alloys at medium temperatures Silicon carbide has a higher refractoriness and chemical inertia than boron Moreover, the SiC CVD-filaments retain a much higher fraction of their room temperature mechanical performances up to about 800 to 1000° C and could be produced in the future at a lower price Despite the fact that SiC seems to be less reactive than boron towards most metals, it nevertheless reacts with titanium and its alloys at rather low temperatures (700 to 800° C) Furthermore, silicon carbide when deposited from a gas phase (eg methyl chlorosilane and hydrogen mixtures) often contains small amounts of more reactive species such as elemental silicon or carbon In the same manner, coatings containing elemental carbon have been applied to SiC CVD-filaments in order to reduce their sensitivity to surface abrasion effects Therefore, SiC filament-titanium matrix composites must be regarded as non-equilibrium systems when they are heated at medium or high temperatures The occurrence of chemical interactions between SiC and titanium in the solid state, controlled by diffusion, has already been established either from experiments performed on diffusion couples with a plane interface [1, 2] or on fibrous composite samples [3–12] However, the nature of the phases and the growth mechanism of the filament-matrix (FM) reaction zone remains a subject of controversy The aim of the present contribution is to analyse, for various well characterized SiC-based CVD-filaments (stoichiometric SiC, SiC with a pyrocarbon coating, SiC with a SiC + C coating) and titanium matrices (unalloyed titanium or Ti-6Al-4V): (a) the FM interaction zone composition, (b) its kinetics of growth in the 700 to 1100° C temperature range, and (c) the growth mechanism The filaments which have been used here have been carefully analysed previously on a chemical, microstructural and mechanical point of view in Part 1 In the same manner, the results of the present study on FM chemical interaction will be later correlated with those of different mechanical characterizations [13, 14]

Synthesis of Macrocyclic Copolymer Brushes and Their Self-Assembly into Supramolecular Tubes

Abstract: We report on an efficient route to design large macrocyclic polymers of controlled molar mass and narrow dispersity. The strategy is based on the synthesis of a triblock copolymer ABC, in which the long central block B is extended by two short A and C sequences bearing reactive antagonist functions. When reacted under highly dilute conditions, this precursor produces the corresponding macrocycle by intramolecular coupling of the A and C blocks. Chloroethyl vinyl ether was selected as the monomer for the central block B, because it can be readily derivatized into brushlike polymers by a grafting process. The corresponding macrocyclic brushes were decorated with polystyrene or randomly distributed polystyrene and polyisoprene branches. In a selective solvent for the polyisoprene branches, the macrocyclic brushes self-assemble into cylindrical tubes of up to 700 nanometers.

Towards an HBV cure: state-of-the-art and unresolved questions—report of the ANRS workshop on HBV cure

Abstract: HBV infection is a major cause of liver cirrhosis and hepatocellular carcinoma. Although HBV infection can be efficiently prevented by vaccination, and treatments are available, to date there is no reliable cure for the >240 million individuals that are chronically infected worldwide. Current treatments can only achieve viral suppression, and lifelong therapy is needed in the majority of infected persons. In the framework of the French National Agency for Research on AIDS and Viral Hepatitis 'HBV Cure' programme, a scientific workshop was held in Paris in June 2014 to define the state-of-the-art and unanswered questions regarding HBV pathobiology, and to develop a concerted strategy towards an HBV cure. This review summarises our current understanding of HBV host-interactions leading to viral persistence, as well as the roadblocks to be overcome to ultimately address unmet medical needs in the treatment of chronic HBV infection.

All-cause mortality in treated HIV-infected adults with CD4 ≥500/mm3 compared with the general population: evidence from a large European observational cohort collaboration

Abstract: Using data from a large European collaborative study, we aimed to identify the circumstances in which treated HIV-infected individuals will experience similar mortality rates to those of the general population.