Comparative determination of ventilatory efficiency from constant load and incremental exercise testing.

The analysis of the relationships between minute ventilation (VE) to CO2 output (VCO2), referred to as ventilatory efficiency, in response to incremental exercise testing, is considered a useful index for assessing the presence and severity of cardiopulmonary and metabolic diseases. The effects of constant load exercise testing performed at work intensity associated with anaerobic threshold (AT) and respiratory compensation points (RCP), on the accurate measurements of ventilatory efficiency are not well known. The aim of this present study was to investigate the reliability of the VE/VCO2 ratio obtained from constant load exercise tests performed with two important metabolic rates (at the AT and RCP) and compare it to that of those of incremental exercise tests. A total of 20 young male (20.8±0.4 yr) subjects initially performed an incremental exercise test and then two constant load exercise tests, on different days. Respiratory and pulmonary gas exchange variables were used to estimate AT and RCP. A paired t-test was used to analyse data. AT and RCP (average) occurred the at 60% and at 71% of peak O2 uptake, respectively. The lowest VE/VCO2 ratio recorded within the first 2 minutes of constant load exercise tests with a work load of AT (26.4±0.3) and RCP (26.7±0.5) was not statistically different from the lowest ratio obtained from the incremental exercise tests (26.0±0.7). In the constant load exercise test, despite the different metabolic rates, the increase in ventilation corresponded closely with the increase in CO2 production, reflecting an optimal ventilation and perfusion ratio. Clinicians should consider the constant load exercise test work load associated with AT and RCP as it provides a meaningful lowest value for ventilatory efficiency.

Environmental evaluation of natural radioactivity in soil near a lignite-burning power plant in Turkey.

Natural radionuclides are released into the environment together with fly ash from the coal-burning power plant and cause an increase in the natural radioactivity in environmental samples. The study concerns to the evaluation the influence of Kangal lignite-burning power plant (LBPP) with a power of 457 MWe, which has been in operation since 1989, on natural radionuclide a concentration in surface soil samples around it. Activity concentrations of natural radionuclides (226Ra, 232Th, 40K and 222Rn) in the soil samples, and emanation coefficient (EC) and mass (ERM) and surface (ERS) exhalation rate of radon were determined by using a gamma-ray spectrometer with an HPGe detector. The average values of 226Ra, 232Th, 40K and 222Rn, EC, ERM and ERS were found as 37±5, 17±3, 222±30Bqkg-1 and 9±1kBqm-3, 12%, 12.1 µBq kg-1 s-1 and 7.1mBqm-2 s-1, respectively. Absorbed gamma dose rate in outdoor air and the corresponding effective dose rate from external exposure and excess lifetime cancer risk were estimated to evaluate radiological hazards for human population. The results revealed that the Kangal LBPP has caused a small increment in 226Ra concentration in the studied area. No influence was observed for 232Th and 40K.

Investigation of the activity level and radiological impacts of naturally occurring radionuclides in blast furnace slag.

The activity level and possible radiological impacts of naturally occurring radionuclides on the health of workers and members of the public, as a result of utilisation of blast furnace slag (BFS) samples as a substitute for aggregate in road construction were investigated by using a gamma-ray spectrometer and potential exposure scenarios given in Radiation Protection 122. The mean activity concentrations of the (226)Ra, (232)Th and (40)K in BFS samples were found to be 152.4, 54.9 and 183.1 Bq kg(-1), respectively. These values are compared with typical values measured in BFS samples from the European Union countries, which are 270, 70 and 240 Bq kg(-1) for (226)Ra, (232)Th and (40)K, respectively. The values of radium equivalent activity index calculated for BFS samples were within the recommended safety limits. The highest total annual effective doses evaluated as 0.9 and 0.4 mSv y(-1) for members of the public and workers, respectively, were lower than the annual limit of 1 mSv y(-1).

A survey of distribution of terrestrial radionuclides in surface soil samples in and around the Osmaniyeprovince, Turkey.

The purpose of this survey was to determine the distribution of terrestrial radionuclides ((238)U, (232)Th and (40)K) in surface soil samples collected from different locations in and around Osmaniye and assess the radiological implications of outdoor external exposure. The activity concentrations of (238)U, (232)Th and (40)K in soil samples ranged from 2.6 to 38.1 Bq kg(-1) with a mean of 10.4±0.7 Bq kg(-1), 3.7-40.5 Bq kg(-1) with a mean of 12.2±0.7 Bq kg(-1) and 30.0-639.7 Bq kg(-1) with a mean of 243.4±12.8 Bq kg(-1), respectively. The concentrations of these radionuclides, presented in this article, were compared with those obtained from similar studies related to Turkey reported in the literature as well as earth's crust average values. The results of the activity concentrations were used to assess the external absorbed gamma dose rate (GDR) in outdoor air and the annual effective dose (AED). The outdoor absorbed GDRs fluctuate from 5.2 to 53.6 nGy h(-1) with a mean of 22.4±9.5. The corresponding mean AED is found to be 0.03 mSv.