The Role of TNFα and Sphingolipid Signaling in Cardiac Hypoxia: Evidence that Cardiomyocytes Release TNFα and Sphingosine

Sphingosine (SPH) is a naturally occurring signaling molecule thought to be responsible for the negative inotropic and cardiotoxic effects of the pro-inflammatory cytokine, TNFα. When subjected to hypoxia and acidosis, Langendorff perfused adult rabbit hearts generate SPH, and isolated adult rat cardiomyocytes released TNFα and SPH into the cell-conditioned media under hypoxic conditions before hypoxia-induced cell permeabilization associated with necrosis. Cardiomyocyte SPH production in response to hypoxia was blocked by TNFRII:Fc which interferes with TNFα binding to its membrane-bound receptor, suggesting that hypoxiatriggered SPH production was TNFα dependent. Extracellular SPH was rapidly converted almost exclusively to S1P by an active sphingosine kinase present in blood components, as seen in vitro and in Langendorff-perfused rat hearts. These results indicate that cardiacderived TNFα and its sphingolipid mediator, SPH, may be important extracellular signals in the heart that contribute to the pathogenesis of cardiac ischemia

The Global Groundwater Crisis

Groundwater depletion the world over poses a far greater threat to global water security than is currently acknowledged

Atmospheric electrification in dusty, reactive gases in the solar system and beyond

Detailed observations of the solar system planets reveal a wide variety of local atmospheric conditions. Astronomical observations have revealed a variety of extrasolar planets none of which resembles any of the solar system planets in full. Instead, the most massive amongst the extrasolar planets, the gas giants, appear very similar to the class of (young) Brown Dwarfs which are amongst the oldest objects in the universe. Despite of this diversity, solar system planets, extrasolar planets and Brown Dwarfs have broadly similar global temperatures between 300K and 2500K. In consequence, clouds of different chemical species form in their atmospheres. While the details of these clouds differ, the fundamental physical processes are the same. Further to this, all these objects were observed to produce radio and X-ray emission. While both kinds of radiation are well studied on Earth and to a lesser extent on the solar system planets, the occurrence of emission that potentially originate from accelerated electrons on Brown Dwarfs, extrasolar planets and protoplanetary disks is not well understood yet. This paper offers an interdisciplinary view on electrification processes and their feedback on their hosting environment in meteorology, volcanology, planetology and research on extrasolar planets and planet formation

Islands in the Pacific: Settings, Distribution and Classification

Oceanic islands have a history of being misunderstood by outsiders, commonly marginalized in global synthesis and planning, their considerable diversity often understated. To capture and explain the diversity of islands in the Pacific, a classification is developing using elevation and lithology (rock type) as the highest level criteria. For each of the 1779 islands, defined as ocean-bounded landmasses ≥1 ha (0.01 km2) in area, data were collected on locations and shapes, areas, names, elevations and lithologies. Eight island types were identified—volcanic high islands (≥30 amsl, ≥80% igneous); volcanic low islands