451 research outputs found
Leptophilic Dark Matter with interactions
We consider a scenario where dark matter (DM) interacts exclusively with
Standard Model (SM) leptons at tree level. Due to the absence of tree-level
couplings to quarks, the constraints on leptophilic dark matter arising from
direct detection and hadron collider experiments are weaker than those for a
generic WIMP. We study a simple model in which interactions of DM with SM
leptons are mediated by a leptophilic boson, and determine constraints on
this scenario arising from relic density, direct detection, and other
experiments. We then determine current LHC limits and project the future
discovery reach. We show that, despite the absence of direct interactions with
quarks, this scenario can be strongly constrained.Comment: 12 pages, 15 figure
Calculation of fully anisotropic liquid crystal waveguide modes
The accurate analysis of optical waveguides is an important issue when designing devices for optical communication. Waveguides combined with liquid crystals have great potential because they allow waveguide tuning over a wide range using low voltages. In this paper, we present calculations that combine an advanced algorithm for calculating liquid crystal behavior and a finite-element mode solver that is able to incorporate the full anisotropy of the materials. Calculation examples demonstrate the validity of our program
High Susceptibility Of Activated Lymphocytes To Oxidative Stress-induced Cell Death.
The present study provides evidence that activated spleen lymphocytes from Walker 256 tumor bearing rats are more susceptible than controls to tert-butyl hydroperoxide (t-BOOH)-induced necrotic cell death in vitro. The iron chelator and antioxidant deferoxamine, the intracellular Ca2+ chelator BAPTA, the L-type Ca2+ channel antagonist nifedipine or the mitochondrial permeability transition inhibitor cyclosporin A, but not the calcineurin inhibitor FK-506, render control and activated lymphocytes equally resistant to the toxic effects of t-BOOH. Incubation of activated lymphocytes in the presence of t-BOOH resulted in a cyclosporin A-sensitive decrease in mitochondrial membrane potential. These results indicate that the higher cytosolic Ca2+ level in activated lymphocytes increases their susceptibility to oxidative stress-induced cell death in a mechanism involving the participation of mitochondrial permeability transition.80137-4
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