Intracavity Frequency Doubling and Difference Frequency Mixing for Pulsed ns Ti:Sapphire Laser Systems at On-Line Radioactive Ion Beam Facilities

Intra-cavity second harmonic generation of a Titanium:sapphire (Ti:sa) laser system has been used to improve the conversion efficiency to the second harmonic. Over the course of several experiments performance data spanning the whole wavelength range of a Ti:sa has been collected, which may be used as a guideline for future experiments. An average output power of up to 3.7 W was achieved, resulting in a conversion efficiency of >75% to the second harmonic. A wavelength coverage from 340–525 nm has been demonstrated. To extend the wavelength range of the solid state laser system, difference frequency mixing has been applied to the intra-cavity doubled light and the fundamental output of a second Ti:sa laser. Up to 30 mW of yellow light at the sodium D2 line at 589 nm was generated. Based on numerical calculations this output power could still be improved by a factor of ten with simple changes in the experimental setup. Laser spectroscopy and measurement of the saturation behaviour has been carried out on an atomic beam of stable sodium

Comparaison inter-laboratoires de profils d’oxylipines par lipidomique ciblée dans le cadre du projet OXYGENATE

Actuellement 20 à 25% de la population adulte mondiale présente un syndrome cardiométabolique. Ce syndrome est un exemple de maladie multifactorielle en lien avec l’alimentation et se caractérise par des troubles cardiovasculaires, métaboliques et inflammatoires. Ces troubles amènent au développement du diabète de type II et des maladies cardiovasculaires. Cependant le diagnostic de ce syndrome n’est pas satisfaisant car pas assez intégratif et précoce pour permettre une prise en charge nutritionnelle. Les oxylipines, métabolites issus de l’oxygénation des acides gras polyinsaturés via différentes voies de biosynthèse, sont connues pour être des médiateurs lipidiques impliqués dans la régulation de processus biologiques liés au syndrome cardiométabolique et dont la biosynthèse est modulée par le statut cardiométabolique et aussi par l’alimentation. D’où l’hypothèse qu’un profilage complet des oxylipines pourrait révéler des perturbations précoces du statut cardiométabolique et pourrait être un nouvel outil d’évaluation de l’efficacité des préventions et interventions nutritionnelles. Le projet OXYGENATE a pour but d’identifier et valider des oxylipines discriminant le statut cardiométabolique et la qualité de l’alimentation. Pour cela, il est nécessaire d’avoir une méthode fiable de profilage quantitatif des oxylipines permettant d’obtenir des profils comparables entre différents laboratoires. Une comparaison inter-laboratoires de notre méthode a été réalisée afin d’estimer les variabilités analytiques et d’identifier les oxylipines critiques. Cinq laboratoires ont préparé (en triplicat et sur 2 jours différents) et analysé 7 plasmas présentant des profils d’oxylipines très contrastés. Les variabilités intra- et inter-jour ainsi que la part de variabilité attribuable à la préparation et à l’appareillage sont évalués. Au-delà de l’intérêt pour le projet, cette comparaison inter-laboratoires unique permettra d’harmoniser les profils d’oxylipines réalisés par l’ensemble de la communauté scientifique

The electron affinity of astatine

One of the most important properties influencing the chemical behavior of an element is the electron affinity (EA). Among the remaining elements with unknown EA is astatine, where one of its isotopes, 211At, is remarkably well suited for targeted radionuclide therapy of cancer. With the At− anion being involved in many aspects of current astatine labeling protocols, the knowledge of the electron affinity of this element is of prime importance. Here we report the measured value of the EA of astatine to be 2.41578(7) eV. This result is compared to state-of-the-art relativistic quantum mechanical calculations that incorporate both the Breit and the quantum electrodynamics (QED) corrections and the electron–electron correlation effects on the highest level that can be currently achieved for many-electron systems. The developed technique of laser-photodetachment spectroscopy of radioisotopes opens the path for future EA measurements of other radioelements such as polonium, and eventually super-heavy elements.peerReviewe

Ly-6C(hi) monocytes dominate hypercholesterolemia-associated monocytosis and give rise to macrophages in atheromata

Macrophage accumulation participates decisively in the development and exacerbation of atherosclerosis. Circulating monocytes, the precursors of macrophages, display heterogeneity in mice and humans, but their relative contribution to atherogenesis remains unknown. We report here that the Ly-6C(hi) monocyte subset increased dramatically in hypercholesterolemic apoE–deficient mice consuming a high-fat diet, with the number of Ly-6C(hi) cells doubling in the blood every month. Ly-6C(hi) monocytes adhered to activated endothelium, infiltrated lesions, and became lesional macrophages. Hypercholesterolemia-associated monocytosis (HAM) developed from increased survival, continued cell proliferation, and impaired Ly-6C(hi) to Ly-6C(lo) conversion and subsided upon statin-induced cholesterol reduction. Conversely, the number of Ly-6C(lo) cells remained unaffected. Thus, we believe that Ly-6C(hi) monocytes represent a newly recognized component of the inflammatory response in experimental atherosclerosis

The electron affinity of astatine

One of the most important properties influencing the chemical behavior of an element is the electron affinity (EA). Among the remaining elements with unknown EA is astatine, where one of its isotopes, 211At, is remarkably well suited for targeted radionuclide therapy of cancer. With the At− anion being involved in many aspects of current astatine labeling protocols, the knowledge of the electron affinity of this element is of prime importance. Here we report the measured value of the EA of astatine to be 2.41578(7) eV. This result is compared to state-of-the-art relativistic quantum mechanical calculations that incorporate both the Breit and the quantum electrodynamics (QED) corrections and the electron–electron correlation effects on the highest level that can be currently achieved for many-electron systems. The developed technique of laser-photodetachment spectroscopy of radioisotopes opens the path for future EA measurements of other radioelements such as polonium, and eventually super-heavy elements