Abundance Patterns in S-type AGB stars : Setting Constraints on Nucleosynthesis and Stellar Evolution Models

During the evolution on the AGB, S-type stars are the first objects to experience s-process nucleosynthesis and third dredge-ups, and therefore to exhibit sprocess signatures in their atmospheres. Their significant mass loss rates (10^-7 to 10^-6 M*/year) make them major contributors to the AGB nucleosynthesis yields at solar metallicity. Precise abundance determinations in S stars are of the utmost importance for constraining e.g. the third dredge-up luminosity and efficiency (which has been only crudely parameterized in all current nucleosynthetic models so far). Here, dedicated S-star model atmospheres are used to determine precise abundances of key s-process elements, and to set constraints on nucleosynthesis and stellar evolution models. A special interest is paid to technetium, an element with no stable isotopes (99Tc, the only isotope produced by the s-process in AGB stars, has a half-life of 2.1 x 10^5 years). Its detection is considered as the best signature that the star effectively populates the thermally-pulsing AGB phase of evolution. The derived Tc/Zr abundances are compared, as a function of the derived [Zr/Fe] overabundances, with AGB stellar model predictions. The [Zr/Fe] overabundances are in good agreement with the model predictions, while the Tc/Zr abundances are slightly overpredicted. This discrepancy can help to set better constraints on nucleosynthesis and stellar evolution models of AGB stars.Comment: 5 pages, 3 figures, To be published in the proceedings of the conference "Why Galaxies Care about AGB Stars II", held in Vienna, August 16-20, 2010; eds Franz Kerschbaum, Thomas Lebzelter, and Bob Wing, ASP Conf. Serie

Treatment of patients with diffuse large B-cell lymphoma

W ostatniej dekadzie odnotowano istotne zwiększenie możliwości terapeutycznych u chorych z chłoniakami rozlanymi z dużych komórek B (DLBCL). W randomizowanych badaniach klinicznych wykazano, że dodanie rytuksymabu do schematu cyklofosfamid, winkrystyna, doksorubicyna, prednizon (CHOP), stosowanego co 3 tygodnie (R-CHOP) przyczyniło się do wydłużenia czasu przeżycia wszystkich badanych grup chorych bez nasilenia toksyczności. Inna strategia, polegająca na skróceniu odstępu pomiędzy kolejnymi cyklami CHOP do 2 tygodni (CHOP-14), również wydaje się możliwa do zastosowania u wszystkich chorych w wieku 18–75 lat, ale prawdopodobnie nie jest bardziej skuteczna niż R-CHOP-21. Strategie zwiększające intensywność dawki są obecnie badane z intencją poprawy wyników leczenia u młodszych chorych z DLBCL o wysokim ryzyku. U chorych w starszym wieku poprawy wyników leczenia można się spodziewać po dołączeniu innych leków do schematu R-CHOP. W przypadku niewystępowania ciężkich chorób towarzyszących jest to wciąż zalecany schemat leczenia w tej grupie wiekowej.In the last 10 years, options for treating patients with diffuse large B-cell lymphoma (DLBCL) have greatly expanded. In randomized clinical studies, the addition of rituximab to cyclophosphamide, vincristine, doxorubicin, prednisone (CHOP) delivered every 3 weeks (R-CHOP) has been associated with improved survival rates, without increased toxicity, in all patient groups studied. Another strategy, giving patients dose-dense CHOP - CHOP every 2 weeks or CHOP-14 - has also been found appropriate for all patients between the ages of 18 and 75 years but probably not superior to R-CHOP-21. Strategies with dose-intense regimens are currently tested for improving the outcome of young patients with poor risk DLBCL. In elderly patients, improvement in outcomes might be caused by the addition of another drug to the R-CHOP regimen. Elderly patients are best treated with R-CHOP if they do not have severe concomitant diseases

COLLABORATION, ORGANISATION : L’IMPACT DU NUMÉRIQUE

International audiencerhion (Observatoire des organisations et des ressources humaines sous l’impact opérationnel du numérique), créé fin 2009 à la Bibliothèque nationale de France, s’est donné pour mission d’observer et d’analyser la mise en place des grands projets numériques à la BnF (numérisation de masse, DL web, Spar – préservation du numérique) et de contribuer à la définition de la collection numérique. Rassemblant des cadres opérationnels, Orhion s’est concentré sur les projets numériques et leur mise en place, avant de s’intéresser aux métiers et leurs évolutions dans un contexte numérique (signalement et magasinage numérique). Orhion travaille actuellement sur les rôles transverses.Orhion propose ici un état des lieux de ses observations autour de deux axes principaux :la mise en œuvre des projets en transversalité à la BnF, ses liens à l’organisation hiérarchique en place et avec l’organisation concrète et élargie que cela nécessite ;l’impact sur les identités professionnelles qui en découle au travers des études sur le signalement et le magasinage numérique

Tetracycline-Loaded Biomimetic Apatite: An Adsorption Study

Biomimetic apatites are appealing compounds for the elaboration of bioactive bone-repair scaffolds due to their intrinsic similarity to bone mineral. Bone surgeries are however often heavy procedures, and the infiltration of pathogens may not be totally avoided. To prevent their development, systemic antibiotic prophylaxis is widespread but does not specifically target surgical sites and involves doses not always optimized. A relevant alternative is a preliminary functionalization by an infection-fighting agent. In this work, we investigated from a physicochemical viewpoint the association of a wide-spectrum antibiotic, tetracycline (TC), and a biomimetic nanocrystalline apatite previously characterized. TC adsorption kinetics and isotherm were thoroughly explored. Kinetic data were fitted to various models(pseudo-first-order, pseudo-second-order, general kinetic model of order n, Elovich, double-exponential, and purely diffusive models). The best fit was found for a doubleexponential kinetic model or with a decimal reaction order of 1.4, highlighting a complex process with such TC molecules which do not expose high-affinity end groups for the surface of apatite. The adsorption isotherm was perfectly fitted to the Sips (Langmuir−Freundlich) model, while other models failed to describe it, and the Sips exponent greater than unity (1.08) suggested a joint impact of surface heterogeneity and positive cooperativity between adsorbed molecules. Finally, preliminary insights on TC release from pelletized nanocrystalline apatite, in aqueous medium and neutral pH, were obtained using a recirculation cell, indicating a release profile mainly following a Higuchi-like diffusion-limited rate. This work is intended to shed more light on the interaction between polar molecules not exhibiting high-affinity end groups and biomimetic apatites and is a starting point in view of the elaboration of biomimetic apatite-based bone scaffolds functionalized with polar organic drugs for a local delivery

Multiscale analysis of geometric planar deformations: application to wild animals electronic tracking and satellite ocean observation data

International audienceThe development of animal tracking technologies (including for instance GPS and ARGOS satellite systems) and the increasing resolution of remote sensing observations call for tools extracting and describing the geometric patterns along a track or within an image over a wide range of spatial scales. Whereas shape analysis has largely been addressed over the last decades, the multiscale analysis of the geometry of opened planar curves has received little attention. We here show that classical multiscale techniques cannot properly address this issue and propose an original wavelet-based scheme. To highlight the generic nature of our multiscale wavelet technique, we report applications to two different observation datasets, namely wild animal movement paths recorded by electronic tags and satellite observations of sea surface geophysical fields

Detailed evaluation of data analysis tools for subtyping of bacterial isolates based on whole genome sequencing : Neisseria meningitidis as a proof of concept

Whole genome sequencing is increasingly recognized as the most informative approach for characterization of bacterial isolates. Success of the routine use of this technology in public health laboratories depends on the availability of well-characterized and verified data analysis methods. However, multiple subtyping workflows are now often being used for a single organism, and differences between them are not always well described. Moreover, methodologies for comparison of subtyping workflows, and assessment of their performance are only beginning to emerge. Current work focuses on the detailed comparison of WGS-based subtyping workflows and evaluation of their suitability for the organism and the research context in question. We evaluated the performance of pipelines used for subtyping of Neisseria meningitidis, including the currently widely applied cgMLST approach and different SNP-based methods. In addition, the impact of the use of different tools for detection and filtering of recombinant regions and of different reference genomes were tested. Our benchmarking analysis included both assessment of technical performance of the pipelines and functional comparison of the generated genetic distance matrices and phylogenetic trees. It was carried out using replicate sequencing datasets of high- and low-coverage, consisting mainly of isolates belonging to the clonal complex 269. We demonstrated that cgMLST and some of the SNP-based subtyping workflows showed very good performance characteristics and highly similar genetic distance matrices and phylogenetic trees with isolates belonging to the same clonal complex. However, only two of the tested workflows demonstrated reproducible results for a group of more closely related isolates. Additionally, results of the SNP-based subtyping workflows were to some level dependent on the reference genome used. Interestingly, the use of recombination-filtering software generally reduced the similarity between the gene-by-gene and SNP-based methodologies for subtyping of N. meningitidis. Our study, where N. meningitidis was taken as an example, clearly highlights the need for more benchmarking comparative studies to eventually contribute to a justified use of a specific WGS data analysis workflow within an international public health laboratory context

Differential influence of instruments in nuclear core activity evaluation by data assimilation

The global activity fields of a nuclear core can be reconstructed using data assimilation. Data assimilation allows to combine measurements from instruments, and information from a model, to evaluate the best possible activity within the core. We present and apply a specific procedure which evaluates this influence by adding or removing instruments in a given measurement network (possibly empty). The study of various network configurations of instruments in the nuclear core establishes that influence of the instruments depends both on the independant instrumentation location and on the chosen network

A one-pot Suzuki-hydrogenolysis protocol for the modular synthesis of 2,5-diaryltetrazoles

2,5-Diaryltetrazoles are a diverse range of compounds of considerable interest within the field of photochemistry as a valuable precursor of the nitrile imine 1,3-dipole. Current literature approaches toward this heterocycle remain unsuitable for the practical synthesis of a library of these derivatives. Herein, we disclose the development of a modular approach toward 2,5-diaryltetrazoles compatible with an array-type protocol, facilitated by a tandem Suzuki-hydrogenolysis approach