Distribution and penetration of reactive oxygen and nitrogen species through a tissue phantom after Plasma Gun treatment

International audienceThe transport and distribution phenomena of reactive oxygen and nitrogen species (RONS) into biological tissue following non-thermal plasma treatment have received much attention. The aim of this study is to test the efficacy of Plasma Gun (PG) on transporting the reactive species in an agar composed tissue phantom. RONS are generated on the agar gel by the plasma treatment and they continue to spread in the depth after plasma exposure. The amount of RONS after passing through the tissue phantom are strongly depending on discharge parameters such as distance to the target and capillary shape

Influence of the HiPIMS voltage on the time resolved platinum ions energy distributions

International audienceHigh Power Impulse magnetron sputtering (HiPIMS) is a common way to create a high and dense ionized metallic vapor without the use of an alternative ionizing device, like radio frequency loops. HiPIMS has been used to perform the deposition of platinum thin films in order to control their morphology. This feature known to depend on the energy of the Pt species incoming onto the substrate during the deposition has to be carefully studied. Therefore, it's necessary to study the ions energy distribution during the sputtering pulse and to follow its evolution with the HiPIMS regime. Pictures of this evolution are presented

Novel Insights into the Bovine Polled Phenotype and Horn Ontogenesis in Bovidae

Despite massive research efforts, the molecular etiology of bovine polledness and the developmental pathways involved in horn ontogenesis are still poorly understood. In a recent article, we provided evidence for the existence of at least two different alleles at the Polled locus and identified candidate mutations for each of them. None of these mutations was located in known coding or regulatory regions, thus adding to the complexity of understanding the molecular basis of polledness. We confirm previous results here and exhaustively identify the causative mutation for the Celtic allele (PC) and four candidate mutations for the Friesian allele (PF). We describe a previously unreported eyelash-and-eyelid phenotype associated with regular polledness, and present unique histological and gene expression data on bovine horn bud differentiation in fetuses affected by three different horn defect syndromes, as well as in wild-type controls. We propose the ectopic expression of a lincRNA in PC/p horn buds as a probable cause of horn bud agenesis. In addition, we provide evidence for an involvement of OLIG2, FOXL2 and RXFP2 in horn bud differentiation, and draw a first link between bovine, ovine and caprine Polled loci. Our results represent a first and important step in understanding the genetic pathways and key process involved in horn bud differentiation in Bovidae

Table-top flash X-ray diagnostics of dodecane sprays

International audienceTime resolved radiography of pure dodecane and cerium doped dodecane sprays expanding through multi-hole production diesel injectors are reported for the first time using a table top flash X-ray source. The radiograph analysis indicates that strong mixing between liquid and ambient gas occurs in the very near nozzle region. The spray is described as two different density components having different penetration velocities. The cone angle, the penetration velocities and the liquid fraction value inferred from the radiographies are in relative good agreement with the recently published results involving very close injector and injection configurations and the reference X-ray diagnostics based on synchrotron radiation. This indicates that the mean energy analysis, re-quired with the use of non monochromatic X-ray sources, appears as a reliable approach. Preliminary measure-ments of multi hole injection characteristics in a chamber inflated up to 30 bars of nitrogen are also documented. Considering the potential improvements likely to be implemented in future experiments, the table top flash X-ray radiography of diesel sprays may offer some promising alternative to the synchrotron studies

Study of pulsed neon xenon VUV radiating low pressure plasmas for mercury free fluorescent sign optimization

International audienceThis work deals with the study and optimization of mercury free fluorescent discharge tubes for publicity lighting applications. The experimental set-up allows for time resolved spectroscopy from 110 up to 900 nm, photometric characterization in a large volume integrating sphere and the current and voltage measurement of microsecond duration signals delivered by lab-developed pulsed drivers. The glow and afterglow radiative process analysis indicates that the best performance measured with the pulsed excitation of rare gas plasma, in comparison with the conventional ac excitation, essentially originates from the efficient plasma relaxation during the afterglow at the benefit of the vacuum ultraviolet (VUV) resonance line radiated at 146.9 nm for xenon. The fit of the VUV time resolved experimental measurements, with the results issued from a simplified kinetic model of neon–xenon plasmas, evidences the crucial role of production of molecular ions during the glow phase and of their radiative recombination during the afterglow. The pulse duration and the gas mixture pressure appear as two experimental parameters whose influence, studied over an extended range, has been demonstrated to bring about a significant sign performance enhancement. There exists an optimum pulse duration range, which results in the appearance of limited stepwise excitation and ionization processes, favourable for an intense afterglow VUV production. The pressure dependence study shows that the best performance for pulsed excitation is obtained in Ne/Xe (100/1) mixtures around 50 mbar, at the difference of an ac driven Ne/Xe plasma for which the best conditions were reported to be of a few millibars. This pressure increase results both in the VUV and sign light output enhancement and the successful continuous operation of pulsed mercury free signs for time as long as 4000 h with neither electrode erosion, nor glass or phosphor degradation nor chromatic coordinate variation. For the green phosphor covered, 65 cm long and 13mm inner diameter signs, the efficiency of a pulsed neon–xenon discharge likely to be operated for a few thousand hours reaches 50% of that of the same tube filled with mercury based mixtures

Lampes fluorescentes sans mercure, à la recherche de l'efficacité énergétique

National audienc

Study and optimization of mercury free fluorescent signs

International audienc

Cinétique d'un plasma de néon-xénon pour le développement de lampes sans mercure

National audienc