Existence of karsts into silicated non-carbonated crystalline rocks in Sahelian and Equatorial Africa, hydrogeological implications

peer reviewedVarious cavities studied in western Niger and South Cameroon show the existence of important karstic phenomena into metagabbros and gneisses. These large-sized eaves resulted from generalized dissolution of silicate formations in spite of their low solubility. Karstification is produced by deep hydrous transfer along lithological discontinuities and fracture net works. The existence of such caves has major implications in geomorphology, under either Sahelian and Equatorial climate, and in hydrogeology and water supply, particularly in the Sahel area

Energy efficiency considerations in integrated IT and optical network resilient infrastructures

The European Integrated Project GEYSERS - Generalised Architecture for Dynamic Infrastructure Services - is concentrating on infrastructures incorporating integrated optical network and IT resources in support of the Future Internet with special emphasis on cloud computing. More specifically GEYSERS proposes the concept of Virtual Infrastructures over one or more interconnected Physical Infrastructures comprising both network and IT resources. Taking into consideration the energy consumption levels associated with the ICT today and the expansion of the Internet in size and complexity, that incurring increased energy consumption of both IT and network resources, energy efficient infrastructure design becomes critical. To address this need, in the framework of GEYSERS, we propose energy efficient design of infrastructures incorporating integrated optical network and IT resources, supporting resilient end-to-end services. Our modeling results quantify significant energy savings of the proposed solution by jointly optimizing the allocation of both network and IT resources

Exosomes released by EBV-infected nasopharyngeal carcinoma cells convey the viral Latent Membrane Protein 1 and the immunomodulatory protein galectin 9

BACKGROUND: Nasopharyngeal carcinomas (NPC) are consistently associated with the Epstein-Barr virus (EBV). Their malignant epithelial cells contain the viral genome and express several antigenic viral proteins. However, the mechanisms of immune escape in NPCs are still poorly understood. EBV-transformed B-cells have been reported to release exosomes carrying the EBV-encoded latent membrane protein 1 (LMP1) which has T-cell inhibitory activity. Although this report suggested that NPC cells could also produce exosomes carrying immunosuppressive proteins, this hypothesis has remained so far untested. METHODS: Malignant epithelial cells derived from NPC xenografts – LMP1-positive (C15) or negative (C17) – were used to prepare conditioned culture medium. Various microparticles and vesicles released in the culture medium were collected and fractionated by differential centrifugation. Exosomes collected in the last centrifugation step were further purified by immunomagnetic capture on beads carrying antibody directed to HLA class II molecules. Purified exosomes were visualized by electron microscopy and analysed by western blotting. The T-cell inhibitory activities of recombinant LMP1 and galectin 9 were assessed on peripheral blood mononuclear cells activated by CD3/CD28 cross-linking. RESULTS: HLA-class II-positive exosomes purified from C15 and C17 cell supernatants were containing either LMP1 and galectin 9 (C15) or galectin 9 only (C17). Recombinant LMP1 induced a strong inhibition of T-cell proliferation (IC50 = 0.17 nM). In contrast recombinant galectin 9 had a weaker inhibitory effect (IC50 = 46 nM) with no synergy with LMP1. CONCLUSION: This study provides the proof of concept that NPC cells can release HLA class-II positive exosomes containing galectin 9 and/or LMP1. It confirms that the LMP1 molecule has intrinsic T-cell inhibitory activity. These findings will encourage investigations of tumor exosomes in the blood of NPC patients and assessment of their effects on various types of target cells

Flexible and Dynamic Control of Network QoS in Grid environments: the QoSINUS approach.

International audienceGrids rely on a complex interconnection of IP domains that may exhibit changing performance characteristics and may offer different quality of service (QoS) facilities. We examine the case of a biomedical application distributed over a grid and show it may suffer from uncontrolled communication performance. Then we present the QoSINUS service that dynamically allocates the network resources to Grid flows in order to match their specific QoS requirements under different load conditions. The aim of this approach is to optimize the end to end performances the heterogeneous mix of grid flows get from the network to enhance the individual application's performance as well as the overall grid infrastructure performance and utilization level. The QoSINUS service is based on the programmable network approach that offers flexibility, evolutivity and enables dynamic adaptation to network load variations. Finally, results of QoSINUS experiments conducted in the context of the eToile french grid testbed based on the high speed and DiffServ capable research network infrastructure, VTHD, are presented

Soft X-Ray Diffraction up to Wavelengths of 6.0Å Becomes Feasible at ID1 of ESRF

Recent experiments carried out at the Anomalous Scattering Beamline ID1 of ESRF are described which show that a cold helium atmosphere provides optimal conditions for protein crystallography with soft X-rays at wavelengths up to 6Å. Image plates are suitable detectors for this wavelength range. The improvement with respect to earlier experiments is considerable. This observation opens the way to the use of anomalous dispersion at the K-edge of light elements, like phosphorus, sulphur, chlorine and calcium. Moreover, there is an interest to use the strong anomalous dispersion of some heavy elements such as uranium (110 anomalous electron units at its M_V edge) to solve large biological structures. The methods of multiwavelength anomalous diffraction and diffraction anomalous fine structure find new resonant labels which are wide spread in living matter and materials