Microstructure and texture of copper/niobium composites processed by ECAE

The structure refinement is a challenge for conductors used for the winding of resistive coils producing non-destructive pulsed magnetic fields over 80T. These nanocomposite conductors composed of a conducting multiscale Cu matrix embedding Nb reinforcing nanofilaments are usually manufactured by using a Severe Plastic Deformation (SPD) process based on hot extrusion, accumulative cold drawing and bundling (ADB) steps [Thilly et al. Philos Mag A 82:925, 2002]. Equal-channel angular extrusion (ECAE) is investigated here as an alternative route since it may provide faster refinement to obtain the ultrafine structure needed for optimized electrical and mechanical properties of the conductors. Therefore, copper-niobium specimens obtained by hot extrusion were processed by ECAE at room temperature. The specific die of the ECAE tool used here is constituted by a round channel with three angles corresponding to a total equivalent strain of about 2.5. Deformed samples were examined by optical microscopy and characterized by hardness profiles and x-ray diffraction (texture pole figures). After one ECAE-pass, the shape of the samples is modified but no trace of damage appeared at the Cu-Nb interfaces. An increase of the hardness values localized in the copper matrix is revealed whereas the hardness of the niobium remains unchanged. Prior to ECAE, the hot extrusion process induced a fibre texture for both copper and niobium. Two fibre texture components were observed for copper: <111> and <200>. A single <110> fibre texture component is evidenced for the niobium. After ECAE a significant variation of the texture is observed in relation with the strong shear induced by this process.     

Trauma healing in refugee camps in guinea: A psychosocial program for Liberian and Sierra Leonean survivors of torture and war.

From 1999 to 2005, the Minneapolis-based Center for Victims of Torture (CVT) served Liberian and Sierra Leonean survivors of torture and war living in the refugee camps of Guinea. A psychosocial program was developed with 3 main goals: (a) to provide mental health care, (b) to train local refugee counselors, and (c) to raise community awareness about war trauma and mental health. Utilizing paraprofessional counselors under the close, on-site supervision of expatriate clinicians, the treatment model blended elements of Western and indigenous healing. The core component consisted of relationship-based supportive group counseling. Clinical interventions were guided by a 3-stage model of trauma recovery (safety, mourning, reconnection), which was adapted to the realities of the refugee camp setting. Over 4,000 clients were provided with counseling, and an additional 15,000 were provided with other supportive services. Results from follow-up assessments indicated significant reductions in trauma symptoms and increases in measures of daily functioning and social support during and after participation in groups. The treatment model developed in Guinea served as the basis for CVT's ongoing work with survivors in Sierra Leone and Liberia. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Structural differences exhibited by networks prepared by chemical or photochemical reactions II — Thermoelastic properties

Thermoelastic properties and swelling measurements were used to characterise networks obtained either by peroxide curing or by photocrosslinking. In agreement with previous studies, it was shown, on the one hand that the measured value of the average molecular weight of a network strand (M _c) depends on its method of determination and that the ratio M _cT/M _cv2m is a characteristic of each crosslinking process, on the other hand photo-crosslinked materials exhibit a more homogeneous distribution of the crosslink points than do peroxide cured samples. Important parameters such as f_e/f, the energetic contribution to the equilibrium retractive force, and d In < r²> ₀/dT, the temperature coefficient of the unperturbed dimension of the macromolecular chain, were determined.     

Structural differences exhibited by networks prepared by chemical or photochemical reactions. I stress-strain properties

Stress-strain properties and swelling measurements were used to characterise networks obtained either by peroxide curing or by photocrosslinking. It was shown that the value of the average molecular weight of a network strand (M _c) is dependent on its methods of determination (m _cf from modulus, M _cv2m from swelling ratios) and that the value of the ratio M _cp/M_cv2m is a characteristic of each crosslinking process. Moreover, the results have shown that the homogeneity of distribution of the crosslinks is dependent on the crosslinking process used.     

Biological Functions and Metabolism of Oleoylethanolamide

The present review is focused on the metabolism and the emerging roles of oleoylethanolamide (OEA) with emphasis on its effects on food intake control and lipid metabolism. The biological mechanism of action, including a non-genomic effect mediated through peroxisome proliferator-activated receptor alpha (PPAR-alpha) and transient receptor potential vanilloid type 1 (TRPV1) receptor, is discussed. The research related to fatty acid ethanolamides has been focused until recently on anandamide and its interaction with cannabinoid receptor subtype 1. The roles of other N-acyl ethanolamine fatty acid derivatives have been neglected until it was demonstrated that OEA can modulate food intake control through interaction with PPAR-alpha. Further investigations demonstrated that OEA modulates lipid and glucose metabolism, and recent study confirmed that OEA is an antagonist of TRVP1. It has been demonstrated that OEA has beneficial effects on health by inducing food intake control, lipid beta-oxidation, body weight loss and analgesic effects. The investigation of the mechanism of action revealed that OEA activates PPAR-alpha and stimulates the vagal nerve through the capsaicin receptor TRPV1. Pre-clinical studies showed that OEA remains active when administered orally.     

Borosilicate nanoparticles prepared by exothermic phase separation

Nanoparticles play an important role in chemical and biological sciences due to their ability to bind and concentrate many molecules on their surface. Polymers and silica are widely used to make nanoparticles, but efforts to make nanoparticles from borosilicate glass--which exhibits high tolerance to chemicals and solvents, combined with excellent mechanical and thermal stability--have proved unsuccessful. Here we show that borosilicate nanoparticles (100-500 nm in size) can be synthesized by simply mixing a silicon-boron binary oxide solution, prepared using non-aqueous organic solvents, with water. This induces a vigorous exothermic phase separation in which borosilicate nanoparticles burst out of a silica phase. In addition to potential applications in the life sciences, monodisperse borosilicate particles could also have applications in the production of photonic bandgap devices with high optical contrast, contrast agents for ultrasonic microscopy or chemical filtration membranes.     

Yeast cell inactivation related to local heating induced by low-intensity electric fields with long-duration pulses

The effects of electric field (EF) treatments on Saccharomyces cerevisiae viability were investigated using a PG200 electroporator (Hoefer Scientific Instrument, San Fransisco, CA, USA) with specific attention to induced thermal effects on cell death. Lethal electric fields (1.5 kV cm(-1) for 5 s) were shown to cause heat variations in the cell suspension medium (water+glycerol), while corresponding classical thermal treatments at equivalent temperatures had no effect on the cells viability. Variations of the electrical conductivity of the intra- and extracellular matrix caused by ions and solutes transfer across the membrane were shown to be involved in the observed heating. The results permitted to build a theoretical model for the temperature variations induced by electric fields. Using this model and the electrical conductivity of the different media, a plausible explanation of the cell death induced by low-intensity electric fields with long-duration pulses has been proposed. Indeed, cell mortality could in part be caused by direct and indirect effects of electric fields. Direct effects are related to well known electromechanical phenomena, whereas indirect effects are related to secondary thermal stress caused by plasma membrane thermoporation. This thermoporation was attributed to electrical conductivity variations and the corresponding intracellular heating.