β-Oxidation of conjugated linoleic acid isomers and linoleic acid in rats

To assess the oxidative metabolism of conjugated linoleic acid (CLA) isomers, rats were force-fed 1.5–2.6 MBq of [1-¹⁴C]-linoleic acid (9c,12c-18∶2),-rumenic acid (9c,11t-18∶2), or-10trans, 12cis-18∶2 (10t, 12c-18∶2), and ¹⁴CO₂ production was monitored for 24 h. The animals were then necropsied and the radioactivity determined in different tissues. Both CLA isomers were oxidized significantly more than linoleic acid. Moreover, less radioactivity was recovered in most tissues after CLA intake than after linoleic acid intake. The substantial oxidation of CLA isomers must be considered when assessing the putative health benefits of CLA supplements.     

THF-induced stiffening of polyelectrolyte/phosphorus dendrimer multilayer microcapsules

Polyelectrolyte multilayer microcapsules are important for a variety of potential applications, and represent a convenient system for studying properties of multilayer films. Recent work explored a post-treatment of such capsules by organic solvents, by reporting a softening. Here we show, that an addition of a very small amount of solvent (THF) to the phosphorus [G₃(NH⁺Et₂Cl⁻)₄₈] dendrimer adsorption solution results, in contrast, in a discernible stiffening of (PSS)/phosphorus dendrimer microcapsules, although it does not affect the multilayer thickness. Our results open new possibilities to tune mechanical properties of multilayer films.     

Augmentation,par régénération électrochimique du substrat,de la production d'une biomasse (thiobacillus ferrooxidans DSM 583) pour un procédé biologique de récupération de métaux

A bioelectrochemical reactor regenerates the substrate of the acidophilic bacterium Thiobacillus ferrooxidans DSM 583 (ferrous ions). This reactor uses a through-flow porous fixed bed or carbon as cathode. A linearizing non-linear regulator insures an efficient control of the intensity imposed to the electrochemical reactor. The protein concentration, correlated to the biomass concentration, is 6.4 fold increased for a 55 h growth, including a 20 h electrolysis. The metal tolerance and the metal fixation capacity of a T. ferrooxidans biomass are presented both for solutions including one or two metallic ions and an industrial waste. A bioelectrochemical process based on these characteristics is proposed for removing metal ions from wastes.     

Deformation mechanisms of metals hardened by a dispersed,incoherent, second phase

Hardening of fcc metals by incoherent particles is analysed. The presence of the particles indirectly determines the rapid multiplication of dislocations in the matrix. The hardening is related to the dense tangles so formed. Recovery of these tangles occurs by cross-slip, climb, and probably by some other complex, thermally activated mechanisms.     

Calcul des réponses impulsionnelles de cibles acoustiquement réfléchissantes

From the wave equation and the use of boundary conditions of the problem we have developped an integral equation which is time dependant. The particular form of this integral equation is well suited to a numerical approximation method which gives the solution as a single boundary layer. If one knows this boundary layer for all space and for all time, one can calculate the spacetime response of the target under investigation. The method is a very general one and can be applied to targets of arbitrary shape. To check the efficiency of the algorithm a computation has been done in the particular case of a perfectly reflecting sphere. Results are in good agreement with classical ones reported in the littérature.     

New perfectly difunctional organolithium initiators for block copolymer synthesis: Synthesis of dilithium initiators in the absence of polar additives

New types of difunctional organolithium initiators have been prepared by addition of sec or tert-butyl lithium on two families of non polymerizable precursors having two non-conjugated double bonds. They were made in pure hydrocarbon solvents such as n-hexane, the dilithium adducts being insoluble and easily purified by elimination of monofunctional species. However, they easily initiate the polymerization of monomers such as conjugated dienes, giving soluble and stable difunctional living polymers in the complete absence of any polar additive.     

Synthesis of 5-hydroxymethyl-2-furancarboxaldehyde catalysed by cationic exchange resins. Part 3. Kinetic approach of the D-fructose dehydration

The best conditions for the production of 5-hydroxymethyl-2-furancarboxaldehyde (HMF) in an ion exchange resin-water-solvent triphasic system have been determined using static operating conditions.     

Photochemistry of benzoin derivatives in an oxygenated polymeric medium

Summary Investigation of the photochemistry of benzoin derivatives in a polymer medium leads to the suggestion that oxygen play an important part in the first processes which occur under U.V. irradiation. This is of interest for the understanding of the photocrosslinking process.     

Etude spectroscopique et R.P.E. du pentaphosphate de cerium

Under ultraviolet excitation cerium pentaphosphate CeP₅O₁₄ shows emission with a quantum efficiency almost independant of the Ce³⁺ concentration and temperature. Energy transfer between the Ce³⁺ ions is not efficient. Decay measurements have been performed and Ce³⁺ decays with τ₁ = 13 10^?9s and τ₂ = 41 10^?9s independently of Ce³⁺ concentration and temperature. The electron spin resonance spectra of Gd³⁺ in Ce_1?xGd_xP₅O₁₄ twin-free crystal are reported and the angular variations of the absorption lines have been fitted to the spin Hamiltonian corresponding to Cs symmetry. Twin-free crystals, selected by EPR measurements, exhibit only the τ₂ lifetime, τ₁ can be induced mechanically in the course of the crash the initially twin-free crystal.