The very forward region of a detector at a linear e/sup +/e/sup -/ collider is a particularly challenging area for instrumentation. In the TESLA detector, two calorimeters, BeamCal (Beam Calorimeter) ...and LumiCal (Luminosity Calorimeter) are planned. The BeamCal is positioned just adjacent to the beampipe. It will be hit by beamstrahlung remnants giving a deposition of several tens of TeV per bunch crossing. The distribution of this energy will be measured to assist in tuning the beams. Single high-energy electrons will be identified and measured. High-energy electron identification is particularly important to veto backgrounds to new particle searches. Several technological options for BeamCal are discussed. Monte Carlo simulations are presented for a diamond/tungsten sandwich structure and compared to results obtained for a heavy element crystal calorimeter. First, tests of sensors are described. The LumiCal will measure larger polar angles than the BeamCal. It will provide a high-precision (O(10/sup -4/)) luminosity measurement from Bhabha scattering. Monte Carlo simulations to optimize the shape and the structure of the calorimeter are presented.
ECONFC050318:0304,2005 This paper presents the status of Monte Carlo simulation of one of the
luminosity detectors considered for the future e+e- International Linear
Collider (ILC). The detector ...consists of a tungsten/silicon sandwich
calorimeter with pad readout. The study was performed for Bhabha scattering
events assuming a zero crossing angle for the beams.
This paper presents the status of Monte Carlo simulation of one of the luminosity detectors considered for the future e+e- International Linear Collider (ILC). The detector consists of a ...tungsten/silicon sandwich calorimeter with pad readout. The study was performed for Bhabha scattering events assuming a zero crossing angle for the beams.
Background. It has become evident that increased nitric oxide (NO) generation may be associated with production of reactive oxygen species, such as peroxynitrite (ONOO−). Peroxynitrite has been ...postulated to be responsible for several of the cytotoxic effects previously ascribed to NO. Since cellular arginine uptake has been shown to modulate nitric oxide synthase activity, we were intrigued to study the effect of ONOO− on arginine traffic in renal mesangial cells. Methods. Arginine uptake, CAT-1 and CAT-2 mRNA expression by northern blotting analysis, and CAT-1 protein content using western blotting were determined in mesangial cells pre-treated with peroxynitrite (0.1 and 0.5 mM) for 2 h. Results. Peroxynitrite induced a significant increase in arginine uptake and CAT-2 mRNA expression compared with untreated cells. In contrast, CAT-1 mRNA expression and protein abundance were diminished. Conclusions. In rat mesangial cells, peroxynitrite augments arginine uptake via augmentation of CAT-2 while decreasing CAT-1 expression.
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