Dermal endothelial cells and keratinocytes produce IL-7 in vivo after human Schistosoma mansoni percutaneous infection

The parasite Schistosoma mansoni infects its definitive mammalian host through an obligatory cutaneous penetration. In this work, we studied early immune response following migration of larvae through human skin, the first immunocompetent organ encountered by the parasite. For this purpose we used an experimental model of severe combined immunodeficient mice engrafted with human skin and injected with autologous PBL. Six days after percutaneous infection, we observed an infiltration of lymphocytes within the human skin, predominantly composed of CD4+ T cells. Moreover, among the cytokines potentially present in the infected skin, immunohistochemistry analysis revealed an in vivo expression of IL-7 in the epidermal layers and strikingly at the level of vascular endothelium. Using an in vitro coculture system, we showed that the S. mansoni larvae directly trigger IL-7 production by human dermal microvascular endothelial cells but not by keratinocytes. Finally, measurements of IL-7 concentrations in plasma of 187 S. mansoni-infected individuals showed that the youngest, which are also the most infected, displayed the highest IL-7 levels. Together, these findings describe dermal endothelial cells as a novel source of IL-7, a cytokine particularly important in schistosomiasis.     

Contribution to frequency control through wind turbine inertial energy storage

An innovative way for wind energy to participate in some sort of frequency control using kinetic energy stored in the rotor for a fast power reserve that could be delivered in a short period (from several seconds up to a few tens of seconds) is presented. This kinetic-energy-based fast reserve is ensured despite wind speed variations - a disoptimisation of the power coefficient through the modification of the rotor speed set point or through the pitch control. In case of a frequency drop, the power coefficient could then be increased to produce more energy. This approach could help to reduce the dynamics and the depth of the frequency drops and therefore allow wind farms to participate in frequency control. Basic economic aspects of the provision of fast power reserve by wind turbines as a function of the amount of reserve considered are also discussed.