Etude de la reactivite du dioxyde d'uranium monocristallin vis-a-vis des processus de dissolution en milieu acide cinetique et reactivite aux interfaces.

International audienc

Dynamic aspects of cerium dioxide sintering: HT-ESEM study of grain growth and pore elimination

International audienceSintering of CeO2 is studied in situ by high temperature scanning environmental microscopy (HT-ESEM) at T = 1400 °C. The morphological modifications of a single grains population are recorded for 6 h. Kinetic parameters are extracted from image series. The local grain growth determined from the single population studied in situ is compared to the general grain growth obtained by classical ex situ technique. Using HT-ESEM for sintering study is validated. The grain boundary velocities range between 0 and 5 μm h−1, with a mean value of about 1 μm h−1. The migration of the intragranular surface pores is described. Their velocities range between 0.4 and 1.2 μm h−1 and depend on pore diameters: the smaller the pore, the faster the pore velocity. The time required to fill a pore that arises at the sample surface is determined as a function of pore diameter. The time for pore elimination dependence with the pore diameters is also established

Validation of a Rapid Rabies Diagnostic Tool for Field Surveillance in Developing Countries

One root cause of the neglect of rabies is the lack of adequate diagnostic tests in the context of low income countries. A rapid, performance friendly and low cost method to detect rabies virus (RABV) in brain samples will contribute positively to surveillance and consequently to accurate data reporting, which is presently missing in the majority of rabies endemic countries.; We evaluated a rapid immunodiagnostic test (RIDT) in comparison with the standard fluorescent antibody test (FAT) and confirmed the detection of the viral RNA by real time reverse transcription polymerase chain reaction (RT-qPCR). Our analysis is a multicentre approach to validate the performance of the RIDT in both a field laboratory (N'Djamena, Chad) and an international reference laboratory (Institut Pasteur, Paris, France). In the field laboratory, 48 samples from dogs were tested and in the reference laboratory setting, a total of 73 samples was tested, representing a wide diversity of RABV in terms of animal species tested (13 different species), geographical origin of isolates with special emphasis on Africa, and different phylogenetic clades. Under reference laboratory conditions, specificity was 93.3% and sensitivity was 95.3% compared to the gold standard FAT test. Under field laboratory conditions, the RIDT yielded a higher reliability than the FAT test particularly on fresh and decomposed samples. Viral RNA was later extracted directly from the test filter paper and further used successfully for sequencing and genotyping.; The RIDT shows excellent performance qualities both in regard to user friendliness and reliability of the result. In addition, the test cassettes can be used as a vehicle to ship viral RNA to reference laboratories for further laboratory confirmation of the diagnosis and for epidemiological investigations using nucleotide sequencing. The potential for satisfactory use in remote locations is therefore very high to improve the global knowledge of rabies epidemiology. However, we suggest some changes to the protocol, as well as careful further validation, before promotion and wider use

Development and validation of sensitive real-time RT-PCR assay for broad detection of rabies virus

Rabies virus (RABV) remains one of the most important global zoonotic pathogens. RABV causes rabies, an acute encephalomyelitis associated with a high rate of mortality in humans and animals and affecting different parts of the world, particularly in Asia and Africa. Confirmation of rabies diagnosis relies on laboratory diagnosis, in which molecular techniques such as detection of viral RNA by reverse transcription polymerase chain reaction (RT-PCR) are increasingly being used.  In this study, two real-time quantitative RT-PCR assays were developed for large-spectrum detection of RABV, with a focus on African isolates. The primer and probe sets were targeted highly conserved regions of the nucleoprotein (N) and polymerase (L) genes.  The results indicated the absence of non-specific amplification and cross-reaction with a range of other viruses belonging to the same taxonomic family, i.e Rhabdoviridae, as well as negative brain tissues from various host species. Analytical sensitivity ranged between 100 to 10 standard RNA copies detected per reaction for N-gene and L-gene assays, respectively. Effective detection and high sensitivity of these assays on African isolates showed that they can be successfully applied in general research and used in diagnostic process and epizootic surveillance in Africa using a double-check strategy

European Bat Lyssavirus Transmission among Cats, Europe

We identified 2 cases of European bat lyssavirus subtype 1 transmission to domestic carnivores (cats) in France. Bat-to-cat transmission is suspected. Low amounts of virus antigen in cat brain made diagnosis difficult

More Accurate Insight into the Incidence of Human Rabies in Developing Countries through Validated Laboratory Techniques

International audienceNo abstract availabl

Genomic Diversity and Evolution of the Lyssaviruses

Lyssaviruses are RNA viruses with single-strand, negative-sense genomes responsible for rabies-like diseases in mammals. To date, genomic and evolutionary studies have most often utilized partial genome sequences, particularly of the nucleoprotein and glycoprotein genes, with little consideration of genome-scale evolution. Herein, we report the first genomic and evolutionary analysis using complete genome sequences of all recognised lyssavirus genotypes, including 14 new complete genomes of field isolates from 6 genotypes and one genotype that is completely sequenced for the first time. In doing so we significantly increase the extent of genome sequence data available for these important viruses. Our analysis of these genome sequence data reveals that all lyssaviruses have the same genomic organization. A phylogenetic analysis reveals strong geographical structuring, with the greatest genetic diversity in Africa, and an independent origin for the two known genotypes that infect European bats. We also suggest that multiple genotypes may exist within the diversity of viruses currently classified as ‘Lagos Bat’. In sum, we show that rigorous phylogenetic techniques based on full length genome sequence provide the best discriminatory power for genotype classification within the lyssaviruses

A review of squeaking in ceramic total hip prostheses

The occurrence of audible squeaking in some patients with ceramic-on-ceramic (CoC) hip prostheses is a cause for concern. Considering multifactor contributing to this phenomenon, many studies have been conducted over the last decade. Great efforts have been put on understanding the mechanics of the hip squeaking to gain a deep insight into factors resulting in sound emission from hip articulation. Disruption of fluid-film lubrication and friction were reported as main potential causes of hip squeaking, while patient and surgical factors as well as design and material of hip implants were identified as affecting factors. This review article therefore summarised the recent available literature on this subject to provide a platform for future developments. Moreover, high wear rates and ceramic liner fracture as viable consequences of hip squeaking were discussed.The first author gratefully acknowledges Macquarie University for International Macquarie University Research Excellence Scholarship (iMQRES)-No. 2010017. The second author would like to thank to the Portuguese Foundation for Science and Technology through the project UID/EEA/04436/2013

Des chauves-souris et des virus : Entre contrôle de l’infection et tolérance immunitaire

International audienceIn recent decades, bats have been associated with numerous viral pandemics. Bats harbor a large variety of viruses, some of which have a high zoonotic potential for humans. While infection with these viruses can be fatal in other mammals, bats are often infected asymptomatically. It is hypothesized that a balanced immune response would enable them to maintain homeostasis during infection, thus limiting viral replication while avoiding the impact of excessive inflammation. Deciphering these mechanisms, using adapted in vitro models, will help assess and avoid the potential zoonotic risk of these animals, while paving the way for the development of therapeutics for infectious and inflammatory diseases.Durant les dernières décennies, les chauves-souris ont été associées à de nombreuses pandémies virales. Ces animaux hébergent en effet une diversité importante de virus, certains à potentiel zoonotique pour l’homme. Alors que ces virus peuvent être mortels chez d’autres mammifères, les chauves-souris sont souvent infectées de façon asymptomatique. La mise en place d’une réponse immunitaire équilibrée leur permettrait de maintenir l’homéostasie lors de l’infection, en limitant la réplication virale tout en évitant l’impact d’une inflammation trop importante. Le décryptage de ces mécanismes, à l’aide de modèles in vitro adaptés, devrait contribuer à évaluer et à éviter le risque zoonotique potentiel de ces animaux, tout en ouvrant la voie au développement de thérapeutiques pour les maladies infectieuses et inflammatoires

Influence du polymorphisme FCGR3A-158 sur la réponse au traitement par rituximab (Mabthéra) chez des patients atteints de lymphomes non hodgkiniens de type folliculaire

TOURS-BU Sciences Pharmacie (372612104) / SudocSudocFranceF