Antiplasmodial Activities of Homogentisic Acid Derivative Protein Kinase Inhibitors Isolated from a Vanuatu Marine Sponge Pseudoceratina sp.

As part of our search for new antimalarial drugs in South Pacific marine sponges, we have looked for inhibitors of Pfnek-1, a specific protein kinase of Plasmodium falciparum. On the basis of promising activity in a preliminary screening, the ethanolic crude extract of a new species of Pseudoceratina collected in Vanuatu was selected for further investigation. A bioassay-guided fractionation led to the isolation of a derivative of homogentisic acid [methyl (2,4-dibromo-3,6-dihydroxyphenyl)acetate, 4a] which inhibited Pfnek-1 with an IC50 around 1.8 μM. This product was moderately active in vitro against a FcB1 P. falciparum strain (IC50 = 12 μM). From the same sponge, we isolated three known compounds [11,19-dideoxyfistularin-3 (1), 11-deoxyfistularin-3 (2) and dibromo-verongiaquinol (3)] which were inactive against Pfnek-1. Synthesis and biological evaluation of some derivatives of 4a are reported

Gamma-ray and radio properties of six pulsars detected by the fermi large area telescope

We report the detection of pulsed γ-rays for PSRs J0631+1036, J0659+1414, J0742-2822, J1420-6048, J1509-5850, and J1718-3825 using the Large Area Telescope on board the Fermi Gamma-ray Space Telescope (formerly known as GLAST). Although these six pulsars are diverse in terms of their spin parameters, they share an important feature: their γ-ray light curves are (at least given the current count statistics) single peaked. For two pulsars, there are hints for a double-peaked structure in the light curves. The shapes of the observed light curves of this group of pulsars are discussed in the light of models for which the emission originates from high up in the magnetosphere. The observed phases of the γ-ray light curves are, in general, consistent with those predicted by high-altitude models, although we speculate that the γ-ray emission of PSR J0659+1414, possibly featuring the softest spectrum of all Fermi pulsars coupled with a very low efficiency, arises from relatively low down in the magnetosphere. High-quality radio polarization data are available showing that all but one have a high degree of linear polarization. This allows us to place some constraints on the viewing geometry and aids the comparison of the γ-ray light curves with high-energy beam models

Death and the Societies of Late Antiquity

Ce volume bilingue, comprenant un ensemble de 28 contributions disponibles en français et en anglais (dans leur version longue ou abrégée), propose d’établir un état des lieux des réflexions, recherches et études conduites sur le fait funéraire à l’époque tardo-antique au sein des provinces de l’Empire romain et sur leurs régions limitrophes, afin d’ouvrir de nouvelles perspectives sur ses évolutions possibles. Au cours des trois dernières décennies, les transformations considérables des méthodologies déployées sur le terrain et en laboratoire ont permis un renouveau des questionnements sur les populations et les pratiques funéraires de l’Antiquité tardive, période marquée par de multiples changements politiques, sociaux, démographiques et culturels. L’apparition de ce qui a été initialement désigné comme une « Anthropologie de terrain », qui fut le début de la démarche archéothanatologique, puis le récent développement d’approches collaboratives entre des domaines scientifiques divers (archéothanatologie, biochimie et géochimie, génétique, histoire, épigraphie par exemple) ont été décisives pour le renouvellement des problématiques d’étude : révision d’anciens concepts comme apparition d’axes d’analyse inédits. Les recherches rassemblées dans cet ouvrage sont articulées autour de quatre grands thèmes : l’évolution des pratiques funéraires dans le temps, l’identité sociale dans la mort, les ensembles funéraires en transformation (organisation et topographie) et les territoires de l’empire (du cœur aux marges). Ces études proposent un réexamen et une révision des données, tant anthropologiques qu’archéologiques ou historiques sur l’Antiquité tardive, et révèlent, à cet égard, une mosaïque de paysages politiques, sociaux et culturels singulièrement riches et complexes. Elles accroissent nos connaissances sur le traitement des défunts, l’emplacement des aires funéraires ou encore la structure des sépultures, en révélant une diversité de pratiques, et permettent au final de relancer la réflexion sur la manière dont les sociétés tardo-antiques envisagent la mort et sur les éléments permettant d’identifier et de définir la diversité des groupes qui les composent. Elles démontrent ce faisant que nous pouvons véritablement appréhender les structures culturelles et sociales des communautés anciennes et leurs potentielles transformations, à partir de l’étude des pratiques funéraires.This bilingual volume proposes to draw up an assessment of the recent research conducted on funerary behavior during Late Antiquity in the provinces of the Roman Empire and on their borders, in order to open new perspectives on its possible developments. The considerable transformations of the methodologies have raised the need for a renewal of the questions on the funerary practices during Late Antiquity, a period marked by multiple political, social, demographic and cultural changes. The emergence field anthropology, which was the beginning of archaeothanatology, and then the recent development of collaborative approaches between various scientific fields (archaeothanatology, biochemistry and geochemistry, genetics, history, epigraphy, for example), have been decisive. The research collected in this book is structured around four main themes: Evolution of funerary practices over time; Social identity through death; Changing burial grounds (organisation and topography); Territories of the Empire (from the heart to the margins). These studies propose a review and a revision of the data, both anthropological and archaeological or historical on Late Antiquity, and reveal a mosaic of political, social, and cultural landscapes singularly rich and complex. In doing so, they demonstrate that we can truly understand the cultural and social structures of ancient communities and their potential transformations, based on the study of funerary practices

Separation and Characterization of Highly Charged Polyelectrolytes Using Free-Solution Capillary Electrophoresis

The characterization of statistical copolymers of various charge densities remains an important and challenging analytical issue. Indeed, the polyelectrolyte (PE) effective electrophoretic mobility tends to level off above a certain charge density, due to the occurrence of Manning counterion condensation. Surprisingly, we demonstrate in this work that it is possible to get highly resolutive separations of charged PE using free-solution capillary electrophoresis, even above the critical value predicted by the Manning counterion condensation theory. Full separation of nine statistical poly(acrylamide-co-2-acrylamido-2-methylpropanesulfonate) polymers of different charge densities varying between 3% and 100% was obtained by adjusting the ionic strength of the background electrolyte (BGE) in counter electroosmotic mode. Distributions of the chemical charge density could be obtained for the nine PE samples, showing a strong asymmetry of the distribution for the highest-charged PE. This asymmetry can be explained by the different reactivity ratios during the copolymerization. To shed more light on the separation mechanism, effective and apparent selectivities were determined by a systematic study and modeling of the electrophoretic mobility dependence according to the ionic strength. It is demonstrated that the increase in resolution with increasing BGE ionic strength is not only due to a closer matching of the electroosmotic flow magnitude with the PE electrophoretic effective mobility, but also to an increase of the dependence of the PE effective mobility according to the charge density

Size-based characterization of nanoparticle mixtures by the inline coupling of capillary electrophoresis to Taylor dispersion analysis

International audienceSeparation of closely related nanoparticles is still a challenging issue for the characterization of complex mixtures for industrial/research applications or regulatory purposes. In this work, the remarkable separating performances of CE were complemented with the absolute size-based determination provided by Taylor dispersion analysis (TDA) for the characterization of nanoparticle mixtures. The inline hyphenation of CE to TDA was successfully implemented for the baseline separation followed by a size-based characterization of a bimodal mixture containing two closely size-related nanolatexes (70nm and 56nm radii). A pixel sensor UV area imager providing three detection points along the capillary was used for a differential measurement of the peak broadening during the Taylor dispersion step. Comparison of this new technique with dynamic light scattering and hydrodynamic chromatography is also discussed

Coupling between Diffusion, Stress Field and Chemical Reaction in a Metal-Gas Oxidation

International audienc

Mechanical Stresses: Inhibitor of Catalyst of High Temperature Oxidation?

International audienc

Colorimetric quantification of amino groups in linear and dendritic structures

International audienceThe aim of the work reported was to develop a procedure using 96-well microtiter plates for the easy determination of protonated groups of compounds including linear poly(amino acid)s and dendritic polymers divided into dendrigraft and dendrimeric structures. This study is a prerequisite step for the quantification of protonated groups in a macromolecule grafted onto a solid surface

Antibody-based surfaces: Rapid characterization using two complementary colorimetric assays

International audienceFinding a general solution for optimizing the grafting of antibody on solid surfaces is difficult due to the variety of material, grafting principles and chemistries or surface formats available (beads, microplates, fibers, etc.). Pre-screening methods able to assess grafting efficiency (GE) and specific activity (SA) are required. In this context, we present here two colorimetric assays that can be used on a wide variety of surface format, chemistry, etc. The first one, ADECA (Amino Density Estimation by Colorimetric Assay) allows a rapid estimation of grafted antibodies and allows calculating the GE. The second one, A2HRP (Antibody Anti-HorseRadish Peroxidase) provides a measure of the amount of active antibody, which, combined to ADECA, is used to determine the SA of grafted antibody. Analytical parameters (limit of detection, repeatability, linearity, etc.) of these two colorimetric assays are presented. Using two commercially available microplates, we demonstrated that, when used in parallel, these rapid and sensitive methods are well adapted to pre-screening of antibody grafting performances