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

Evidence of solid-solution reaction upon lithium insertion into cryptomelane K0.25Mn2O4 material

Cryptomelane-type K0.25Mn2O4 material is prepared via a template-free, one-step hydrothermal method. Cryptomelane K0.25Mn2O4 adopts an I 4/m tetragonal structure with a distinct tunnel feature built from MnO6 units. Its structural stability arises from the inherent stability of the MnO6 framework which hosts potassium ions, which in turn permits faster ionic diffusion, making the material attractive for application as a cathode in lithium-ion batteries. Despite this potential use, the phase transitions and structural evolution of cryptomelane during lithiation and delithiation remains unclear. The coexistence of Mn3+ and Mn4+ in the compound during lithiation and delithiation processes induce different levels of Jahn-Teller distortion, further complicating the lattice evolution. In this work, the lattice evolution of the cryptomelane K0.25Mn2O4 during its function as a cathode within a lithium-ion battery is measured in a customized coin-cell using in-situ synchrotron X-ray diffraction. We find that the lithiation-delithiation of cryptomelane cathode proceeds through a solid-solution reaction, associated with variations of the a and c lattice parameters and a reversible strain effect induced by Jahn-Teller distortion ofMn3+. The lattice parameter changes and the strain are quantified in this work, with the results demonstrating that cryptomelane is a relatively good candidate cathode material for lithium-ion battery use

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

Borates de terres rares TCr (BO3)2 de structure dolomite

Vicat J., Aléonard Suzanne. Borates de terres rares TCr (BO3)2 de structure dolomite. In: Bulletin de la Société française de Minéralogie et de Cristallographie, volume 91, 3, 1968. pp. 293-295

Borates de structure dolomie

Aléonard Suzanne, Vicat J. Borates de structure dolomie. In: Bulletin de la Société française de Minéralogie et de Cristallographie, volume 89, 2, 1966. pp. 271-272