Urinary Benzene Biomarkers and DNA Methylation in Bulgarian Petrochemical Workers: Study Findings and Comparison of Linear and Beta Regression Models

Chronic occupational exposure to benzene is associated with an increased risk of hematological malignancies such as acute myeloid leukemia (AML), but the underlying mechanisms are still unclear. The main objective of this study was to investigate the association between benzene exposure and DNA methylation, both in repeated elements and candidate genes, in a population of 158 Bulgarian petrochemical workers and 50 unexposed office workers. Exposure assessment included personal monitoring of airborne benzene at work and urinary biomarkers of benzene metabolism (S-phenylmercapturic acid [SPMA] and trans,trans-muconic acid [t,t-MA]) at the end of the work-shift. The median levels of airborne benzene, SPMA and t,t-MA in workers were 0.46 ppm, 15.5 µg/L and 711 µg/L respectively, and exposure levels were significantly lower in the controls. Repeated-element DNA methylation was measured in Alu and LINE-1, and gene-specific methylation in MAGE and p15. DNA methylation levels were not significantly different between exposed workers and controls (P>0.05). Both ordinary least squares (OLS) and beta-regression models were used to estimate benzene-methylation associations. Beta-regression showed better model specification, as reflected in improved coefficient of determination (pseudo $R^2$) and Akaike’s information criterion (AIC). In beta-regression, we found statistically significant reductions in LINE-1 (−0.15%, P<0.01) and p15 (−0.096%, P<0.01) mean methylation levels with each interquartile range (IQR) increase in SPMA. This study showed statistically significant but weak associations of LINE-1 and p15 hypomethylation with SPMA in Bulgarian petrochemical workers. We showed that beta-regression is more appropriate than OLS regression for fitting methylation data

DISTRIBUTION OF BIOCHEMICAL AND MOLECULAR-GENETIC MARKERS OF GENES IN WORKERS OF COAL MINING ENTERPRISES OF KUZBASS REGION SUFFERING FROM CHRONIC DUST BRONCHITIS

Distribution of genotypes of biochemical markers of HP, GC, EsD, АсР genes, genotypes on polymorphic variants of the genes coding enzymes of biotransformation GSTT1 (GST-ɵ1) and GSTM1 (GST-μ1) and NOS3 (VNTR4 polymorphism) in the miners with chronic mechanic bronchitis, and in persons without this occupational pathology is investigated. It is shown that the owners of EsD 1-2, АсР bb genotypes are most subject to development of chronic mechanic bronchitis. Endogen factors of resistance to this disease are GC 1-1, EsD 1-1, АсР bc genotypes

Intercalibration of the barrel electromagnetic calorimeter of the CMS experiment at start-up

Calibration of the relative response of the individual channels of the barrel electromagnetic calorimeter of the CMS detector was accomplished, before installation, with cosmic ray muons and test beams. One fourth of the calorimeter was exposed to a beam of high energy electrons and the relative calibration of the channels, the intercalibration, was found to be reproducible to a precision of about 0.3%. Additionally, data were collected with cosmic rays for the entire ECAL barrel during the commissioning phase. By comparing the intercalibration constants obtained with the electron beam data with those from the cosmic ray data, it is demonstrated that the latter provide an intercalibration precision of 1.5% over most of the barrel ECAL. The best intercalibration precision is expected to come from the analysis of events collected in situ during the LHC operation. Using data collected with both electrons and pion beams, several aspects of the intercalibration procedures based on electrons or neutral pions were investigated

First measurements of the performance of the Barrel RPC system in CMS

During the summer 2006, a first integrated test of a part of the CMS experiment was performed at CERN collecting a data sample of several millions of cosmic rays events. A fraction of the Resistive Plate Chambers system was successfully operated. Results on the RPC performance are reported

An RPC-based Technical Trigger for the CMS Experiment

In the CMS experiment, sub-detectors may send special trigger signals, called "Technical Triggers", for special purposes like test and calibration. The Resistive Plate Chambers are part of the Muon Trigger System of the experiment, but might also produce a cosmic muon trigger as Technical Trigger to be used during the commissioning to the detectors, the CMS magnet Test Cosmic Challenge and the later running of CMS. The proposed implementation is based on the development of a new board, the RBC Balcony Collector (RBC); the test results on prototypes and their performance during the recent CMS Cosmic Challenge are presented

CMS physics technical design report : Addendum on high density QCD with heavy ions

Peer reviewe

Design and operational aspects of a bi-polar semi-conductor switch as possible candidate for replacement of electro-mechanical switchgear in energy extraction systems for the LHC corrector magnet circuits

More than 600 DC opening switches assure the role of energy extraction in the powering circuits of the bipolar, superconducting beam corrector magnet chains in the LHC collider at CERN. Although the operational experience from several years of extensive use has proven the high reliability of the electro-mechanical breakers, their relatively high need for regular, preventive maintenance and subtle adjustments as well as their limited lifetime has stimulated the interest in considering alternative solutions. The paper presents the development and operational performance details of a prototype, 1 kA, bipolar extraction switch based on back-to-back IGCT's with blocking diodes. The specific features related to the zero-current passing are described and quantified. The associated difficulties for the controls of a powering system to assure the necessary current stability at the transitory points are analyzed, considering the requirements from the beam dynamics. Parameters of various solutions are described in details

Random telegraph noise in the photoluminescence of individual GaxIn1-xAs quantum dots in GaAs

We have investigated random telegraph noise in the photoluminescence from InGaAs quantum dots in GaAs. Dots switching among two and three levels have been measured. The experiments show that the switching InGaAs dots behave very similarly to switching InP dots in GaInP. but differently from the more commonly investigated colloidal dots. The switching is attributed to defects, and we show that the switching can be used as a monitor of the defect