The Whipple Observatory 10 m γ-ray telescope has been used to survey the error boxes of EGRET unidentified sources in an attempt to find counterparts at energies of 350 GeV and above. Twenty-one unidentified sources detected by EGRET (more than 10% of the total number) have been included in this survey. In no case is a statistically significant signal found in the EGRET error box, which implies that, at least for this sample, the γ-ray spectra of these sources steepen between 100 MeV and 350 GeV. For each EGRET source location, we list candidate associations and derive upper limits on the integral γ-ray flux above 350 GeV.
29 May 2017 in International Journal of Occupational Medicine and Environmental Health
Objectives: The main aim has been to examine psychometric properties of STOP-Bang (snoring, tiredness, observed apnea, high blood pressure, body mass index (BMI), age, neck circumference, male gender) scoring model (Serbian translation), an obstructive sleep apnea (OSA) screening tool, in a...
1 October 2014 in Mutation Research - Genetic Toxicology and Environmental Mutagenesis
Ionizing radiation causes detrimental health effects such as cancer and genetic damage. The study aim was to determine predictors for micronuclei (MN) occurrence and frequency in peripheral blood lymphocytes of health workers professionally exposed to radiation. Health workers, age matched, selected for the study on regular check-ups, were divided according to the radiation exposure. The exposed group involved nuclear medicine department employees (54) and the control group comprised workers from other departments (36). Data about workers characteristics and habits, received annual doses (AD), total years of service (TYS) and exposed years of service (EYS) were taken from each subject. Blood samples were taken and micronuclei (MN) number in peripheral blood lymphocytes was calculated using CBMN assay according to standard protocols. Most workers were female, technicians, with mean age of 45.67 years and EYS about 15 years. Health workers exposed to radiation had significantly more MN than controls (p = 0.001). Female gender, older age, higher received annual doses, longer EYS and TYS increased the MN number. Technicians and laboratory workers have higher risk for MN occurrence. Significant predictors of MN formation according to constructed model were workers age, sex, AD and EYS. One EYS year increases MN frequency 1.017 times, while receiving 0.1 mSy raises MN frequency by 26 %. EYS accurately predicts 86.30 % of MN frequencies and AD 64.60 %. The model, developed for the first time in this study, showed that received annual doses and duration of exposure to radiation can be used for prediction of MN numbers.
1 January 2011 in Srpski arhiv za celokupno lekarstvo
Introduction. Silicosis, the most prevalent of the pneumoconioses, is caused by inhalation of crystalline silica particles. Silica-exposed workers are at increased risk for tuberculosis and other mycobacterium-related diseases. The risk of a patient with silicosis developing tuberculosis is higher (2.8 to 39 fold higher, depending on the severity of silicosis) than that found in healthy controls. Outline of Cases. The first patient was a 52-year-old male who was admitted in 2002 for the second time with dyspnoea, wheezing and fatigue over the last 11 years. He had worked in an iron smelting factory and was exposed to silica dust for 20 years. First hospitalization chest radiography showed bilateral pleural adhesions, diffuse lung fibrosis with signs of a specific lung process. Second hospitalization chest radiography showed bilateral massive irregular, non-homogenous calcified changes in the upper and middle parts of lungs. The patient died due to respiratory failure and chronic pulmonary heart in 2007. The main causes of his death were silicotuberculosis and chronic obstructive pulmonary disease. The second patient was a 50-year-old male who was admitted in 2005 for the second time with chest tightness, dyspnoea, wheezing and fatigue over the last 10 years. He had worked in an iron smelting factory and was exposed to silica dust for 30 years. First hospitalization chest radiography showed diffuse lung fibrosis and small nodular opacities. The patient was diagnosed with silicosis, small opacities sized level p/q, and profusion level 2/3. Second hospitalization chest radiography and CT showed diffuse lung fibrosis and small nodular opacities predominantly in the upper lobes. The patient was recognized as having an occupational disease, and received early retirement due to disability. Conclusion. In low-income countries, new cases of silicosis and associated lung cancer, chronic obstructive pulmonary disease and tuberculosis are likely to be seen for decades because necessary reduction of silica use will take time to be achieved.
Background: The aim of this study was to analyze the impact of low doses of ionizing radiation on healthcare workers using dosimeter data and several biomarkers of effects, and to asses the suitability of those tests. Methods: Data from the last medical examinations, obtained from the medical records of 148 employees were analysed. They were divided into three groups: nuclear medicine, interventional radiology and general radiology. The examination included hematological parameters and cytogenetical tests: unstable chromosomal aberrations (UCA) and micronucleus test (MNT). The received cumulative 5-year dose was calibrated into personal dose equivalents Hp(10). Results: A statistically significant difference was found between the groups in the UCAs (c2=6.634, p=0.036) with the highest UCA frequency in nuclear medicine. The ANOVA showed a statistically significant difference in the values of erythrocytes (F(2,140)=3.715, p=0.027), monocytes (F(2,127)=3.326, p=0.039) and platelets (F(2,135)=4.209, p=0.017), with higher erythrocytes and lower platelets in interventional radiology and lower monocytes in nuclear medicine, all with small effect size. The dose was significantly different among the groups (c2 =22,191; p<0.001). The nuclear medicine workers received a higher dose compared to interventional radiology (U=458, p<0.001) and general radiology (U=510.5, p<0.001). Conclusions: Nuclear medicine employees are at a higher risk of developing neoplastic and blood-related diseases due to consistent exposure to low doses of ionizing radiation. Results suggest that UCA test might be more suitable for detecting radiation-induced damage at low doses than MNT. Compulsory monitoring of the health status at periodic examinations is required to prevent occupational diseases, esp. among the nuclear medicine workers.