We present results of the performance of the second prototype of the CASTOR quartz–tungsten sampling calorimeter, to be installed in the very forward region of the CMS experiment at the LHC. The ...energy linearity and resolution, as well as the spatial resolution of the prototype to electromagnetic and hadronic showers are studied with E=20–200 GeV electrons, E=20–350 GeV pions, and E=50, 150 GeV muons from beam tests carried out at CERN/SPS in 2004. The responses of the calorimeter using two different types of photodetectors (avalanche photodiodes APDs, and photomultiplier tubes PMTs) are compared.
We present performance studies of a full-length prototype for the CASTOR quartz-tungsten sampling calorimeter, installed in the very forward region of the CMS experiment at the LHC. The response ...linearity and energy resolution, the uniformity, as well as the showers’ spatial properties in the prototype have been studied with electrons, pions and muons of various energies. A special study was also carried out for testing the light-output with a 90-degree cut of the quartz plates of the calorimeter. The data were taken during the CASTOR test beam at CERN/SPS in 2007.
We investigated the darkening of two high
OH
-
content quartz fibres irradiated with 24
GeV protons at the Cern PS facility IRRAD. The two tested fibres have a 0.6
mm quartz core diameter, one with ...hard plastic cladding (qp) and the other with quartz cladding (qq). These fibres were exposed at about 1.25
Grad in 3 weeks. The fibres became opaque below 380
nm and in the range 580–650
nm. The darkening under irradiation and damage recovery after irradiation as a function of dose and time are similar to what we observed with electrons. The typical attenuation at 455
nm are
1.44
±
0.22
and
2.20
±
0.15
dB
/
m
at 100
Mrad for qp and qq fibres, respectively. The maximum damage recovery is also observed near this wavelength.
Diabetes mellitus (DM) has a negative effect on cardiovascular functions. Little, however, is known of the overall effect of DM on the cardiac histology or the pathophysiological basis of this.
We ...aimed to investigate the role of oxidative stress on the pathogenesis of diabetic cardiomyopathy in an experimental model.
12 week-old female Sprague Dawley rats were randomly allocated into a healthy control group (n=6) and an DM group (n=6). After 12 weeks of alloxan induced DM, the groups' cardiac tissues were histopathologically analyzed and examined for determination of oxidant and antioxidant enzymes activities of catalase (CAT), superoxide dismutase (SOD), and myeloperoxidase (MPO) and amount of reduced glutathione (GSH) and lipid peroxidation (LPO).
When compared to the control group, the DM group showed cardiomyopathic changes. In the DM group, activities of CAT (144 +/- 0.9 vs. 112 +/- 1.4, p < 0.05) and LPO amount (27.0 +/- 0.74 vs. 14.4 +/- 0, 20, p < 0.05) were significantly increased whereas activities of SOD (142 +/- 0.2 vs. 146 +/- 0.7, p < 0.05) and amount of GSH (3.48 +/- 0.01 vs. 3.73 +/- 0.01, p < 0.05) were significantly decreased when compared to the control group. Besides, activities of MPO (7.3 +/- 0.02 vs. 8.6 +/- 0.11, p < 0.05) were comparable between groups.
Using the experimental animal model, we were able to demonstrate that DM causes cardiomyopathic changes, and we propose that these changes could be mediated by an oxidative stress.
The quantum energy surgical device (QESD) employs an innovative, "no-touch" thermal coagulation, incision and evaporation technique in which thermal energy is delivered to tissue in the format of ...high-energy neutral argon gas atoms. The aim of this study is to compare QESD and bipolar coagulation (BC) through assessment of both haemostasis and histological damage to isolated femoral arteries of rats.
Sixty rats were randomly divided into acute and short-term experimental groups. In the acute group (n=20) histopathological evaluation was performed immediately following coagulation, whereas in the short-term experimental group (n=20) the evaluation was performed 10 days later. Each sham group consisted of ten rats. Viewed under the surgical microscope, only normal-appearing, freshly sectioned, and bleeding femoral arteries were studied. Right femoral arteries subject to QESD coagulation, and left femoral arteries to BC. Haemorrhaging was controlled using the minimal coagulation time necessary to stop it. All vascular layers, including endothelium, internal elastic lamina, media and adventitia were examined histologically and ultrastructurally in a "blind" fashion to critically compare morphological damage due to QESD and BC.
Surgical haemostasis induced by QESD was found to be as safe as BC. Light microscopy revealed more marked histopathological changes in the BC than in the QESD group. These involved mainly the endothelial and medial compartments and, at the ultrastructural level, consisted of endothelial degeneration and exfoliation, irregularity of internal elastic lamina, degeneration, and loss of medial smooth muscle.
The results indicate that QESD coagulation induces significantly less histological damage than does BC. Thus QESD coagulation is a safe, less tissue destructive, and equally effective method of haemostasis.
Objective: A prospective study of newly exposed cotton workers was performed to investigate the natural history of respiratory symptoms and lung function changes. Methods: A total of 157 workers ...naive to cotton dust exposure were investigated by questionnaire, spirometry, and skin tests. They were examined before employment (baseline) and at the end of the first week, and the first, third, sixth, and 12th month after starting work. Acute airway response was defined as either a cross-first-shifl or a cross-week fall in forced expiratory volume in one second (FEV₁). The longitudina change of lung function over the year was aho calculated. Five hundred seventy-two personal dust sampling and 191 endotoxin measurements were performed to assess th exposure. Results: Forty percent of workers reported work-related symptoms in the fi week of the study. Smoking, endotoxin, and dust concentrations were nsk factors for all work-related symptoms. Acute airway responses were witnessed after immediate exposure. Female status was the only factor found to be predictive of acute airway response. The mean longitudinal fall in FEV₁ at 1 year was 65.5 mL (standard error = 37.2). Age, early respiratory symptoms, and early fall in cross-week FEV₁. were found to predict the 12-month fall in FEV₁. Cross-first-shift and cross-week falh FEV₁ reduced in magnitude during the course of the study. Conclusions: This study of workers naive to cotton dust exposure has demonstrated that respiratory symptoms and acute airway responses develop early following first exposure, and a tolerance effe develops in those workers with the continued exposure. Current smoking and increasing exposure predicts the development of work-related lower respiratory tract symptoms, while early symptoms and acute airway changes across the working week predict the longitudinal loss of lung function at 1 year.
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