Simulation of Heavily Irradiated Silicon Pixel Sensors and Comparison with Test Beam Measurements

Charge collection measurements performed on heavily irradiated p-spray DOFZ pixel sensors with a grazing angle hadron beam provide a sensitive determination of the electric field within the detectors. The data are compared with a complete charge transport simulation of the sensor which includes signal trapping and charge induction effects. A linearly varying electric field based upon the standard picture of a constant type-inverted effective doping density is inconsistent with the data. A two-trap double junction model implemented in the ISE TCAD software can be tuned to produce a doubly-peaked electric field which describes the data reasonably well. The modeled field differs somewhat from previous determinations based upon the transient current technique. The model can also account for the level of charge trapping observed in the data.Comment: 8 pages, 11 figures. Talk presented at the 2004 IEEE Nuclear Science Symposium, October 18-21, Rome, Italy. Submitted to IEEE Transactions on Nuclear Scienc

Cell-Autonomous Control of Neuronal Dendrite Expansion via the Fatty Acid Synthesis Regulator SREBP

Summary: During differentiation, neurons require a high lipid supply for membrane formation as they elaborate complex dendritic morphologies. While glia-derived lipids support neuronal growth during development, the importance of cell-autonomous lipid production for dendrite formation has been unclear. Using Drosophila larva dendritic arborization (da) neurons, we show that dendrite expansion relies on cell-autonomous fatty acid production. The nociceptive class four (CIV) da neurons form particularly large space-filling dendrites. We show that dendrite formation in these CIVda neurons additionally requires functional sterol regulatory element binding protein (SREBP), a crucial regulator of fatty acid production. The dendrite simplification in srebp mutant CIVda neurons is accompanied by hypersensitivity of srebp mutant larvae to noxious stimuli. Taken together, our work reveals that cell-autonomous fatty acid production is required for proper dendritic development and establishes the role of SREBP in complex neurons for dendrite elaboration and function. : Ziegler et al. highlight the endogenous role of fatty acid synthesis for proper neuronal dendrite growth during development. Using Drosophila da neurons, they show that large CIVda neurons cell-autonomously rely on fatty acid synthesis through the lipid synthesis master regulator SREBP. Keywords: Drosophila, dendrite differentiation, fatty acids, lipids, SREBP, metabolism, brain, nociceptio

Perioperative Use of Levosimendan: Best Practice in Operative Settings

LEVOSIMENDAN HAS BEEN USED in clinical practice since 2000, especially in the care of heart-failure patients. It probably is the most studied inotropic agent ever, with 83 randomized controlled trials published about adult critically ill patients1 (PubMed search updated January 6, 2012). The molecular mechanisms of levosimendan action recently have been described in detail elsewhere2 and are based on, but not limited to, the Ca2-sensitizing effect in the cardiac myofilaments. Pleiotropic effects include activation of adenosine triphosphate– sensitive sarcolemmal K channels of smooth muscle cells (linked to vasodilation) and activation of adenosine triphosphate– sensitive K channels in cardiovascular mitochondria (involved in a cardioprotective effect). The active long-lived metabolite OR-1896, also an inodilator,3,4 allows the cardiovascular effects of levosimendan to persist up to 7 to 9 days after the discontinuation of a 24-hour infusion of the drug.