Previous studies on the degenerative animal model of multiple sclerosis suggested that the copper-chelator cuprizone might directly suppress T-cell functions. Peripheral T-cell function in the ...cuprizone model has already been explored; therefore, in the present study, we investigated, for the first time, how cuprizone feeding affects the thymus, the organ of T-cell maturation and selection. We found that even one week of cuprizone treatment induced significant thymic atrophy, affecting the cortex over the medulla. Fluorescent microscopy and flow-cytometric analyses of thymi from cuprizone- and vehicle-treated mice indicated that eradication of the cluster of the differentiation-4 (CD4)-CD8 double-positive T-cell subset was behind the substantial cell loss. This result was confirmed with CD3-CD4-CD8 triple-staining experiments. Ultrastructurally, we observed degraded as well as enlarged mitochondria, myelin-bodies, large lipid droplets, and large lysosomes in the thymi of cuprizone-treated mice. Some of these features were similar to those in physiological and steroid-induced accelerated aging. According to our results, apoptosis was mainly of mitochondrial origin mediated by both caspase-3- and apoptosis inducing factor-mediated mechanisms. Additionally, mitogen activated protein kinase activation and increased pro-apoptotic B cell lymphoma-2 family protein expression were the major underlying processes. Our results do not indicate a functional relationship between cuprizone-induced thymus involution and the absence of inflammatory responses or the selective demyelination observed in the cuprizone model. On the other hand, due to the reversible nature of cuprizone's deleterious effects, the cuprizone model could be valuable in studying thymus regeneration as well as remyelination processes.
We present the results of beam tests with high-energy (8–375 GeV) electrons, pions, protons and muons of a sampling calorimeter based on the detection of Cherenkov light produced by shower particles. ...The detector, a prototype for the very forward calorimeters in the CMS experiment, consists of thin quartz fibers embedded in a copper matrix. Results are given on the light yield of this device, on its energy resolution for electron and hadron detection, and on the signal uniformity and linearity. The signal generation mechanism gives this type of detector unique properties, especially for the detection of hadron showers: narrow, shallow shower profiles and extremely fast signals. These specific properties were measured in detail. The implications for measurements in the high-rate, high-radiation Large Hadron Collider (LHC) environment are discussed.
The experiments at the Large Hadron Collider (LHC) will have to deal with unprecedented radiation levels. In the large-rapidity regions, close to the beam pipe, these levels reach megagrays per year. ...The detectors to be installed in these regions, the HF Calorimeters, are designed to operate under these conditions. In this paper, we describe the results of studies in which a prototype calorimeter was exposed to radiation of the type and intensity expected at the LHC. These studies made it possible to estimate the effects of this radiation on the response and the resolution of the calorimeter as a function of time during LHC operation.
CMS very forward calorimeter is based on a quartz fibre technology. The calorimeter prototype composed of two longitudinal segments was tested at CERN in 1996. We present the test beam data analysis ...of this prototype. It was shown that the mean values of responses for pions and electrons of the same energy could be equalised using the appropriate ratio of calibration constants for longitudinal segments. The beam test data were used to simulate the calorimeter response to hadron jets.
We present test-beam data analysis of a quartzfibre calorimeter prototype composed of a single active section with a passive absorber in front of it. The partial suppression of the electromagnetic ...showers leads to the equalization of the response to electrons and pions for a given depth of this passive section. Results are compared with the Monte-Carlo expectations.
PDF
