An Institutional Personal Learning Environment Enabler

In this paper, we first discuss the concept of Personal Learning Environment (PLE) with respect to higher- education institutions and Virtual Learning Environments (VLEs). This discussion rapidly confronts us to the place of the PLE and self-directed learning and/or training inside the institution. We therefore introduce the concept of institutional PLE enabler, which is expected to stimulate students to create and use their own resources and institutional resources and share them with peers during formal and informal learning activities. Next, we describe a proposal for a federated design and implementation of the PLE enabler across multiple institutions

Mechanisms of leukemogenesis induced by bovine leukemia virus: prospects for novel anti-retroviral therapies in human

In 1871, the observation of yellowish nodules in the enlarged spleen of a cow was considered to be the first reported case of bovine leukemia. The etiological agent of this lymphoproliferative disease, bovine leukemia virus (BLV), belongs to the deltaretrovirus genus which also includes the related human T-lymphotropic virus type 1 (HTLV-1). This review summarizes current knowledge of this viral system, which is important as a model for leukemogenesis. Recently, the BLV model has also cast light onto novel prospects for therapies of HTLV induced diseases, for which no satisfactory treatment exists so far

Human exposure to allergenic pollens: A comparison between urban and rural areas

Background: Pollinosis is found more frequently in urban areas than in rural environments. This could be partly related to the different types of pollen exposure in these dissimilar areas. The objective of this study was to compare the distribution of pollen in these environments across an urbanization gradient. Methods: Daily pollen abundances were obtained in France using Hirst-type sensors. Sampling was conducted from January to June in 2003 and 2006 in a rural area, a semi-rural area and in two urban areas, which were characterized by several urbanization criteria. Results: Total allergenic pollen abundance was higher in rural and semi-rural areas than in urban areas irrespective of the sampling year. Multivariate analyses showed that pollen exposures differed according to the type of area and were strongly explained by the urbanization gradient. Grass, ash, birch, alder, hornbeam, hazel and plantain pollen quantities exceeded the allergy threshold more often in rural settings than in urban areas. In urban areas, only plane pollen quantities exceeded the allergy threshold more often than in rural areas. Conclusions: Allergenic pollen exposure is higher in rural areas than in urban areas, and the most abundant pollen in each area did not originated from the same taxa. This result should be taken into account in epidemiological studies comparing allergies in rural and urban areas to adapt the panel of pollen extracts for human environmental exposure. In addition, this study highlights that some ornamental trees produce a large number of allergenic pollens and provide new sources of aeroallergens. © 2011 Elsevier Inc

Finishing the euchromatic sequence of the human genome

The sequence of the human genome encodes the genetic instructions for human physiology, as well as rich information about human evolution. In 2001, the International Human Genome Sequencing Consortium reported a draft sequence of the euchromatic portion of the human genome. Since then, the international collaboration has worked to convert this draft into a genome sequence with high accuracy and nearly complete coverage. Here, we report the result of this finishing process. The current genome sequence (Build 35) contains 2.85 billion nucleotides interrupted by only 341 gaps. It covers ∼99% of the euchromatic genome and is accurate to an error rate of ∼1 event per 100,000 bases. Many of the remaining euchromatic gaps are associated with segmental duplications and will require focused work with new methods. The near-complete sequence, the first for a vertebrate, greatly improves the precision of biological analyses of the human genome including studies of gene number, birth and death. Notably, the human enome seems to encode only 20,000-25,000 protein-coding genes. The genome sequence reported here should serve as a firm foundation for biomedical research in the decades ahead

La stratigraphie tertiaire et la surface d'érosion messinienne sur les marges occidentales de la mer Noire: stratigraphie sismique haute résolution

Jury : Jean-Pierre SUC (Rapporteur), Nicolas PANIN (Rapporteur), Jean-Loup RUBINO (Rapporteur), Jacques DEVERCHERE (Président de Jury), Jean-Pierre REHAULT (Directeur de thèse), Gilles LERICOLAIS (Encadrant scientifique), Georges CLAUZON (Personnalité invitée), Corneliu DINU (Personnalité invitée)The Tertiary paleogeographic evolution of the Black Sea, within the paratethys realm, was characterised by several periodic isolation episodes. The eutatic responses of the Black Sea to these de-connexions, and particularly those related to the Mediterranean Messinian crisis, are still not clearly established. The high resolution seismic stratigraphy study we present is based on interpretation of multichanel HR seismic data correlated with drillings recovered on the occidental Black Sea margin. Our investigations were concentrated on the identification of erosional surfaces, interpreted as markers of eustatic falls, linked to the basin isolation phases. On the Romano-Ukrainian shelf, the seismic profiles display six major discontinuities regarded as Tertiary erosional surfaces : (1) the surfaces underlined at the base of the Eocene (E), at the base of the Oligocene (O), in the Middle Miocene (M) and at the base of the Pontian (P); (2) and two intra-Pontian erosional unconformities (L.IPU and IPU). On the other hand, the Messinian erosional surface was clearly identified on the Bulgaro-Turckish margin. Recent correlation between the Paratethysian and Mediterranean stratigraphic scale suggest that the IPU surface recognised on the Romano-Ukrainian shelf is equivalent to the Messinian erosional surface. Among the five ante-Messinian erosional surfaces described, we interpret the M surface as the signature of a catastrophic sea level fall related to the Upper Burdigalian isolation phase. We propose that the four other surfaces correspond either to submarine erosion episodes, or to transgressive events. The discovery of the Messinian erosional surface in Black Sea constituting the major result of this study, enables to validate the assomption about the Messinian Dessiccation of the Black Sea [Hsü and Giovanoli, 1979].La mer Noire, dans le cadre de son évolution au sein de la Paratéthys, a connu au cours du Tertiaire de nombreux épisodes d'isolement. L'impact de ces phases de déconnexion, et en particulier de celle liée à la crise messinienne en Méditerranée, sur l'évolution eustatique de la mer Noire fait l'objet de ce travail de recherche. L'étude est basée sur l'analyse de données sismiques multitraces HR, corrélées à de nombreux forages. Nos investigations, menées sur les marges occidentales du bassin, se sont concentrées sur l'identification de surfaces d'érosion que nous avons tenté d'interpréter en terme de chutes du niveau marin, à mettre en lien avec ces phases d'isolement. Sur la marge roumano-ukrainienne, cette étude a permis de mettre en évidence six surfaces d'érosion au sein des séries tertiaires : les surfaces d'érosion à la base de l'Eocène (E), de l'Oligocène (O), du Miocène moyen (M) et du Pontien (P); et enfin les surfaces d'érosion L.IPU et IPU au sein du Pontien. Sur la marge bulgaro-turque, nos recherches ont permis la découverte et le calage chronostratigraphique précis, par le biais des forages DSDP, de la surface d'érosion messinienne en mer Noire. Les plus récentes corrélations entre les échelles stratigraphiques paratéthysiennes et méditerranéennes montrent que la surface IPU est l'équivalent, sur le plateau roumano-ukrainien, de la surface d'érosion messinienne découverte sur la marge turque. Parmi les cinq surfaces d'érosion anté-messiniennes décrites, nous démontrons que la surface M constitue la signature d'une chute drastique du niveau de la mer Noire répondant à l'épisode d'isolement de la fin du Burdigalien. Nous proposons que les autres surfaces d'érosion anté-messiniennes correspondent soit à des épisodes d'érosion sous-marine, soit à des événements transgressifs. Résultat majeur de cette étude, la découverte de la surface d'érosion messinienne en mer Noire permet de valider définitivement l'hypothèse, proposée par Hsü [Hsü and Giovanoli, 1979], de l'effondrement du niveau de la mer Noire à la fin du messinien

Messinian event in the black sea: Evidence of a Messinian erosional surface

In 1975, sediment cores from leg DSDP 42b (sites 380A and 381) revealed a thin sediment layer in the Black Sea basin which points to a shallow water environment at the Miocene-Pliocene boundary. With these facts and in the wake of hypothesis of the Messinian Salinity Crisis (MSC), it was proposed that the Black Sea, like the Mediterranean Sea, suffered a desiccation period at the end of the Messinian (Hsü, K.J. and Giovanoli, F., 1979. Messinian event in the Black Sea. Palaeogeography, Palaeoclimatology, Palaeoecology, 29: 75–93). Whereas the main topics of the MSC in the Mediterranean Sea is now widely accepted, the lack of evidence for a Messinian erosional surface in the Black Sea left the debate about the Messinian desiccation of this basin open until today. The analysis of high resolution multi-channel seismic data acquired during the BlaSON surveys brings important new elements for this scientific debate: (1) Down the slope offshore the Bosporus, we show a clear erosional surface correlated to the top of the Upper Miocene shallow water environment unit of site DSDP 381. The overlying Lower Zanclean unit inevitably dates this erosional surface of the Messinian event. (2) A wide intra-Pontian erosional surface (IPU) is evidenced on the Romanian shelf. The IPU is characterized by a sharp decrease in the incision rate from outer (deep canyons) to inner shelf (superficial incisions network). According to the most recent Paratethyan and Mediterranean stratigraphic scale correlations, the IPU erosional surface is considered as the analogue to the Messinian erosional surface described down the slope offshore the Bosporus. In addition to recently discovered inland erosional signature, the wide regional erosional surface we underline on the Western Black Sea margins validates the Black Sea Messinian desiccation hypothesis. We also demonstrate that evaporative draw-down of the Black Sea implied the installation in the basin of a negative hydrologic budget during the Messinian. The lack of a major Messinian Danube canyon on the Romanian shelf supports the hypothesis of a Messinian Danube trapped in the Dacic basin. However, the presence of a Messinian superficial incision network connecting the location of the modern Danube delta to deeply incised Messinian canyons on the outer shelf (IPU) makes the hypothesis of a Danube reaching the partially desiccated Black Sea still possible

Nanoparticules recouvertes de dérivés amphiphiles de hyaluronate pour la vectorisation de molécules d'intérêt pour le traitement des pathologies de l'articulation

Lorsque le cartilage est altéré, la réponse des chondrocytes est insuffisante pour stopper ce processus et réparer le tissu. Les thérapies non chirurgicales actuelles sont basées sur les anti-inflammatoires pour soulager la douleur. Cependant, certaines molécules thérapeutiques ne sont pas utilisées en raison d'une faible biodisponibilité ou d'effets secondaires importants. Le but est de préparer des particules polymère pour améliorer la biodisponibilité dans l'articulation de principes actifs (PA). Ceci est obtenu par le recouvrement des particules par des dérivés de l'acide hyaluronique (HA), naturellement présent dans le cartilage et qui possède une affinité pour un récepteur (CD44) à la surface des chondrocytes. Ce ciblage actif permet de concentrer les PA à proximité ou dans (internalisation) ces cellules et donc, d'obtenir un effet à des concentrations plus faibles en PA. Le HA est estérifié par des groupements hydrophobes pour obtenir des propriétés tensio-actives. Puis ces dérivés servent de stabilisant pour la formulation d'émulsions conduisant à l'obtention de particules polymère. Elles sont alors caractérisées: taille, distribution et quantité de HA modifié en surface. L'encapsulation de traceurs fluorescents démontre une internalisation in vitro et l'administration par injection intra-articulaire (ia) chez le rat n'engendre pas d'inflammation. L'encapsulation de PA (HA, chondroïtine sulfate) est possible, avec des tailles de particules plus importantes. Ceci ouvre de nouvelles approches dans le traitement des atteintes articulaires: l'injection ia de particules polymère recouvertes de HA permet un adressage des molécules qu'elles contiennent dans les cellulesA defect in articular cartilage yield to a biological response of the chondrocytes but it is not sufficient to stop the damage or heal the tissue. The non-chirurgical therapies available are based on anti-inflammatory, to relieve the pain. But, many molecules which might have therapeutic effects are not used because of poor bioavailability or severe side effects. Here, we described the elaboration of polymeric nanoparticles that can enhance articular bioavailability of entrapped drugs. One can reach this goal by using HA derivatives at the surface of such particles. HA is a polysaccharide naturally present in the joint, with a strong affinity for one receptor expressed by the chondrocytes: CD44. Such an active targeting will allow the accumulation of drugs near or in the cells (internalization) and therefore, lead to biological effects with lower concentration. We chemically modified the HA by esterification with hydrophobic chains to confer tensio-actives properties. Then, those derivatives were used to stabilize the formulation of polymeric particles and the characterization (size, distribution and amount of HA derivatives present) was determined. The encapsulation of fluorescent probes proved in vitro an internalization by the chondrocytes. Moreover, intra-articular (ia) injection of particles in healthy rats did not generate any inflammation. Entrapment of molecules (HA or Chondroitin Sulfate) was possible but the size was higher and the encapsulated amount could not be precisely measured. This work is promising for new therapies in articular diseases, the ia injection of polymeric particles covered by HA derivatives allow an active targeting of the entrapped drugsMETZ-SCD (574632105) / SudocNANCY1-Bib. numérique (543959902) / SudocNANCY2-Bibliotheque electronique (543959901) / SudocNANCY-INPL-Bib. électronique (545479901) / SudocSudocFranceF