Human and bovine respiratory syncytial virus vaccine research and development

Human (HRSV) and bovine (BRSV) respiratory syncytial viruses (RSV) are two closely related viruses, which are the most important causative agents of respiratory tract infections of young children and calves, respectively. BRSV vaccines have been available for nearly 2 decades. They probably have reduced the prevalence of RSV infection but their efficacy needs improvement. In contrast, despite decades of research, there is no currently licensed vaccine for the prevention of HRSV disease. Development of a HRSV vaccine for infants has been hindered by the lack of a relevant animal model that develops disease, the need to immunize immunologically immature young infants, the difficulty for live vaccines to find the right balance between attenuation and immunogenicity, and the risk of vaccine-associated disease. During the past 15 years, intensive research into a HRSV vaccine has yielded vaccine candidates, which have been evaluated in animal models and, for some of them, in clinical trials in humans. Recent formulations have focused on subunit vaccines with specific CD4+ Th-1 immune response-activating adjuvants and on genetically engineered live attenuated vaccines. It is likely that different HRSV vaccines and/or combinations of vaccines used sequentially will be needed for the various populations at risk. This review discusses the recent advances in RSV vaccine development

In vivo evidence for quasispecies distributions in the bovine respiratory syncytial virus genome

We analyzed the genetic evolution of bovine respiratory syncytial virus (BRSV) isolate W2-00131, from its isolation in bovine turbinate (BT) cells to its inoculation in calves. Results showed that the BRSV genomic region encoding the highly variable glycoprotein G remains genetically stable after virus isolation and over 10 serial infections in BT cells, as well as following experimental inoculation in calves. This remarkable genetic stability led us to examine the mutant spectrum of several populations derived from this field isolate. Sequence analysis of molecular clones revealed an important genetic heterogeneity in G coding region of each population, with mutation frequencies ranging from 6.8 to 10.1 10-4 substitutions/nucleotide. The non-synonymous mutations of the mutant spectrum mapped preferentially within the two variable antigenic regions of the ectodomain or close to the highly conserved domain. These results suggest that RSV populations may evolve as complex and dynamic mutant swarms, despite apparent genetic stability

Mass transfer and hydrodynamic characteristics of new carbon carbon packing: Application to CO2 post-combustion capture

A novel structured packing, the 4D packing, has been characterized in terms of hydrodynamics, effective area and gas side mass transfer coefficient. The increase of the 4D opening fraction allows to reduce pressure drop and to get a better capacity than Mellapak 500Y and 750Y, for which the geometric areas are similar. The 50% open 4D packing, 4D-50%, leads to effective areas which are higher than Mellapak 500Y ones, and doubled compared with Mellapak Plus 252Y ones. Effective areas for the 4D do not decrease when the opening fraction increases from 30 to 50%, this indicates that a non-negligible amount of droplets is generated at 50%. Gas side mass transfer coefficient had been measured with an original experimental method: water evaporation. Corresponding results seem to be in agreement with the literature, and with the fact that a large amount of droplets is generated. Correlations are proposed for both effective area and gas side mass transfer coefficient for the 4D-50%.The 4D-50% packing could be very interesting for post-combustion CO2 capture since it generates low pressure drop and a very high interfacial area. This will be further confirmed by an economic study for which the absorber plant will be designed with a rate based model

Performance characteristics of a new structured packing

A new structured packing using carbon fibres, called Sepcarb® 4D, is presented. This packing has several attractive properties, such as high voidage (ε=94%) and high effective area (a=420 m2 m−3). These properties are advantageous for packing used as a gas–liquid contactor for separation units. To determine the internal characteristics of this packing, we performed several experiments using a 150-mm-internal-diameter column. Firstly, hydrodynamics experiments were conducted using an air–water counter current flow to determine the pressure drop (for both dry and wet packing) and flooding point. Secondly, the mass transfer efficiency was determined in terms of HETP (height equivalent to theoretical plate) by total reflux experiments with an n-heptane/cyclohexane mixture at atmospheric pressure. Hydrodynamic performance and mass transfer efficiency were compared with those of packings generally used in distillation and absorption

Counting CTL

The original publication is available at www.springerlink.com.International audienceThis paper presents a range of quantitative extensions for the temporal logic CTL. We enhance temporal modalities with the ability to constrain the number of states satisfying certain sub-formulas along paths. By selecting the combinations of Boolean and arithmetic operations allowed in constraints, one obtains several distinct logics generalizing CTL. We provide a thorough analysis of their expressiveness and of the complexity of their model-checking problem (ranging from P-complete to undecidable)

Counting LTL

The original publication is available at ieeexplore.ieee.org.International audienceThis paper presents a quantitative extension for the linear-time temporal logic LTL allowing to specify the number of states satisfying certain sub-formulas along paths. We give decision procedures for the satisfiability and model checking of this new temporal logic and study the complexity of the corresponding problems. Furthermore we show that the problems become undecidable when more expressive constraints are considered

Inondations dominées de Graphes Valués

Projet TIMC (Traitement d'Images Multi-Cible)National audienceEnjeux et verrous technologiques : Si on considère un niveau de gris comme une altitude, toute image à niveaux de gris peut être vue comme un relief topographique. La morphologie mathématique a développé les nivellements, opérateurs puissants pour le filtrage de bruit ou la simplification d'images avant segmentation. Les nivellements agissent localement comme des inondations, remplissant les cuvettes par des lacs ou comme des arasements, aplanissant les pics. Ces opérations sont très coûteuses en temps de calcul et les images à traiter sont de plus en plus volumineusesL'enjeu est de trouver des algorithmes rapides, parallélisables, et pouvant s'exécuter sur des architectures variées. Compétences développées : Considérons un relief topographique dont l'inondation a un niveau uniforme. A mesure que ce niveau augmente, de nouveaux lacs se créent dans des minima et d'autres lacs fusionnent. La suite des lacs ainsi créée a une structure arborescente.Cette remarque est à la base de notre travail : - Construction à partir d'une image 2D ou 3D de la structure arborescente - Modélisation mathématique des inondations sur une telle structure (structure de treillis des inondations, inondation maximale sous un plafond) - Développement d'un algorithme d'inondation se factorisant en inondations multiples sur des sous-arbres beaucoup plus petits. - Retour à l'image pour visualiser le résultat.Résultats : - Mise au point et validation d'un nouvel algorithme - Conception d'un simulateur interactif - Mise en oeuvre efficace (20 millions de nœuds en quelques secondes) - Parallélisation de la phase du calcul des hauteurs finales - Mise en oeuvre parallèle efficace - Publication et présentation dans une conférence internationale.Impacts et perspectives : Les algorithmes d'inondation sont l'ingrédient de base de nombreux filtres morphologiques, tels que les nivellements, indispensables pour traiter des problèmes complexes. Pour une tâche donnée, de nombreux nivellements peuvent être nécessaires. Ils sont souvent utilisés en cascade pour une analyse multi-échelle de textures. Ne trouveront leur place dans des applications industrielles ou médicales que les algorithmes suffisamment rapides et capables de traiter de gros volumes de données. Il en va de même dans des applications interactives où le temps de réponse doit être immédiat

Librairie indépendante et les enjeux du commerce électronique (La)

Cette étude a été réalisée par M. François Hurard et Mme Catherine Meyer-Lereculeur, en novembre 2012, dans le cadre de la mission d\u27expertise sur le portail numérique de la librairie indépendante. Pour conjurer la fuite de ses clients vers les sites de vente en ligne, la librairie indépendante doit aller au-delà de son rôle de conseil et d’animation. Elle doit également répondre aux attentes des lecteurs, en leur garantissant de disposer, dans un délai raisonnable, des ouvrages qu’ils commandent dans une librairie physique ou sur son site internet personnalisé