Umbilical Cord Blood Banking

[À l'origine dans / Was originally part of : CRDP - Droit, biotechnologie et rapport au milieu]The umbilical cord, previously considered as waste and discarded at birth, is a source of haematopoietic stem cells. Current therapeutic uses of umbilical cord blood stem cells and the promise of these cells for the treatment of degenerative diseases in the future have led to the establishment of cord blood banks in many parts of the world. Although umbilical cord blood banking raises many ethical and legal issues, this article focuses on the controversy created by the coexistence of public and private cord blood banks in many countries. Policy statements adopted by professional associations and advisory groups indicate that, based on the current state of medical evidence, childbearing women with no current or potential familial need of stem cell transplantation should be encouraged to donate cord blood to public banks

Comparison of phenolic and volatile profiles of edible and toxic forms of Detarium senegalense J. F. GMEL

In Senegal, Detarium senegalense J.F. Gmel. (ditax in Wolof) is one of the most important important forest fruit species. However, exploitation of the edible fruit is based on local people's knowledge. Only trees whose fruits are consumed by animals are exploited. To identify them, a chemical comparison of edible and toxic forms was done in order to highlight differences between both forms. Dichloromethane leaf extracts from toxic and edible trees were analyzed by gas chromatography. Phenolic profile and volatile compounds from fruits extracts were studied respectively by High Performance Liquid Chromatography-mass spectrometry (HPLC-MS) and Gas Chromatography Mass Spectrometry (GC-MS). Cytotoxicity effect of fruits extracts was evaluated on murine macrophage cells J774 A1. GC-analysis of dichloromethane leaf extracts revealed the presence of lupenone and lupeol only in toxic extracts. 6'-O-galloyl-epiheterodendrin and isovaleronitrile were detected in toxic pulp. However, no cytotoxic effect was found in our conditions. This study has given the opportunity to identify within the same species, compounds which could differentiate both edible and toxic forms. Nevertheless further studies are needed to better understand which compounds are responsible for toxicity in the toxic form. (Résumé d'auteur

Efficient Raman converter in the yellow range with high spatial and spectral brightness

International audienceWe present a Raman converter emitting at 583 nm on the second Stokes order of a line of propan-2-ol pumped by a microlaser at 532 nm in the sub-nanosecond regime. We used a mixture of liquids to adapt the transmission band of a photonic bandgap fiber. The internal conversion efficiency is 67% in photon numbers, and the output power is 1.06 mW, corresponding to a maximum peak power of 338 W. The beam delivered by the converter presents a Gaussian spatial structure and a high spectral brightness, typically more than five times higher than supercontinuum sources in this spectral range

Observation of surface acoustic wave Brillouin scattering in optical microfibers (Orale)

International audienceWe report the observation of surface-acoustic-wave Brillouin scattering (SAWBS) in a subwavelength-diameter fiber and show that this effect relies on the generation by the electrostrictive force of phonons confined at the surface of the microwire

Stimulated Raman scattering with large Raman shifts with liquid core Kagome fibers (Orale)

International audienceStimulated Raman scattering in photonic band gap liquid filled fibers is known to be an attractive technique for manufacturing efficient wavelength converters. However the possible frequency shifts are limited by the spectral bandwidth of these fibers. We experimentally demonstrate that Kagome fibers allow to greatly enlarge these shifts

BAUTISTA, ANA E HIJO [Material gráfico]

Copia digital. Madrid : Ministerio de Educación, Cultura y Deporte, 201

Structural and Barrier Properties of Compatibilized PE/PA6 Multinanolayer Films

The barrier performance and structural lightening of organic materials are increasingly desired and constitute a major challenge for manufacturers, particularly for transport and packaging. A promising technique which tends to emerge in recent years is that of multinanolayer coextrusion. The advantage is that it can produce multilayers made of thousands of very thin layers, leading to new properties due to crystalline morphology changes induced by confinement. This paper is focusing on the study of multinanolayered films with alternated polyethylene (PE), compatibilizer (PEgMA) and polyamide 6 (PA6) layers and made by a forced assembly coextrusion process equipped with layer multiplying elements (LME). PE/PA6 multilayer films consisting of 5 to 2049 layers (respectively 0 to 9 LME) were successfully obtained with well-organized multilayered structure. The evolution of the morphology and the microstructure of these two semi-crystalline polymers, when the thickness of each polymer layer decreases from micro-scale to nano-scale, was correlated to the water and gas transport properties of the PE/PA multilayers. The expected improvement of barrier properties was limited due to the on-edge orientation of crystals in very thin PE and PA6 layers. Despite this change of crystalline morphology, a slight improvement of the gas barrier properties was shown by comparing experimental results with permeabilities predicted on the basis of a serial model developed by considering a PE/PA6 interphase. This interphase observed by TEM images and the on-edge crystal orientation in multilayers were evidenced from mechanical properties showing an increase of the stiffness and the strength