Assessment the Natural Radioactivity of Radionuclides ( 226Ra, 232Th, 40K, and 137Cs) in Wheat Grain

This paper investigates the activity concentration of radionuclides (226Ra, 232Th, 40K and 137Cs) in the wheat grain samples using a high-purity germanium detector. Thirty-six wheat grain samples were collected from different locations of Koya City, Iraqi Kurdistan region. Average activity concentrations of 226Ra, 232Th and 40K in wheat grain are found to be 0.407 ± 0.097 Bq.kg-1 for 226Ra, 0.36 ± 0.14 Bq.kg-1 for 232Th and 109.25± 2.214 Bq.kg-1 for 40K, respectively. The measured activity concentrations for the radionuclides are compared with the reported data from other countries. In addition, the fallout radionuclide of 137Cs has no detection of in the wheat grain samples. The radium equivalent activity Raeq, internal and external hazard indices Hin and Hex, and annual gonadal dose equivalent are calculated for the measured samples. The total ingestion dose is 113.19 µSv.y-1, which is below the world average value of 290 µSv.y-1.

Optimization of fly ash content in cement and assessment of radiological risk

As for all materials of mineral origin, fly ash contains natural radionuclides such as 226Ra, 232Th and 40K which contribute to radiation exposure. The present study is aimed to investigate variation of natural radionuclides (226Ra, 232Th and 40K) in Ordinary Portland Cement due to variation in the concentration of fly ash. For this purpose, seven cement–fly ash mixtures were experimentally tested for radiological content with NaI(Tl) gamma spectrometer. From the measured gamma-ray spectra, radium equivalent, hazard indices, gamma index, annual effective and gonadal dose were determined. Radium equivalent for samples ranged from 209.53 Bq kg−1 to 336.06 Bq kg−1 with a mean of 265.41 Bq kg−1. The external and internal hazard indices varied from 0.57 to 0.91 Bq kg−1 and 0.64 to 1.13 Bq kg−1, respectively. The gamma index exceeded unity for samples with fly ash concentration greater than or equal to 20% by mass. The average annual effective and gonadal dose from different cement–fly ash mixtures was 0.92 mSv y−1 and 0.95 mSv y−1, respectively. The study demonstrated that as concentration of fly ash increased in the cement, the concentration of 226Ra and 232Th also increased, whereas 40K content remained the same for all practical purposes.

Radioactivity concentrations and dose assessments of therapeutic peloids from some Turkish spas

The activity concentrations of natural radionuclides in peloids were studied to assess the radiologic hazard from 18 Turkish spas. The peloids are mainly used for therapeutic treatments, rheumatic diseases and aesthetic purposes. The concentrations of the natural radionuclides 226Ra, 232Th, 40K and 137Cs were determined with a gamma ray spectrometer using a HPGe detector. The average activity concentrations of 226Ra, 232Th, 40K, and 137Cs in the peloids studied were 110.69, 71.52, 576.48 and 0.447 Bq/kg, respectively. The radium equivalent activities in the peloid samples ranged from 63.3 to 766.77 Bq/kg. The absorbed dose rate (Dout) varied between 37.52 and 330.67 nGy/h and most of the observed spa doses are greater than the worldwide recommended values. The annual effective dose values range from 0.26 to 2.78 μSv/y. The annual gonadal dose equivalents of the samples vary from 224.07 to 2283.55 with a mean of 821.99 μSv/y.

Radioactivity in soil from Mojkovac, Montenegro, and assessment of radiological and cancer risk

Soil samples from Mojkovac, Montenegro, were analyzed by standard gamma-spectrometry for radioactivity due to 226Ra, 232Th, 40K, and 137Cs. Average activity concentrations have been found to be 28.6, 43.1, 620.8, and 55 Bq/kg, respectively. In order to evaluate the radiation hazard, radium equivalent activity, absorbed dose rate, annual effective dose, external and internal hazard indexes, and the annual gonadal dose equivalent were determined and found to be at an average of 133.79 Bq/kg, 65.18 nGy/h, 79.93 mSv/y, 0.37, 0.45, and 0.46 mSv/y, respectively. With life expectancy taken to be 70 years, a mean lifetime outdoor gamma radiation was calculated as 5.6 mSv, yielding a lifetime cancer risk of 2.8?10-4.

Divergent gonadotropin-gonadal dose-responsive coupling in healthy young and aging men

The present study extends a recent composite model of in vivo interglandular signaling to assess the impact of age on 1) nonequilibrium exchange among diffusible and protein-bound testosterone (Te); 2) elimination of total and free Te; 3) basal and pulsatile Te secretion (sec); 4) the implicit feedforward function mediating luteinizing hormone (LH) concentration (con) drive of instantaneous Te sec; and 5) possible stochastic variability of the predicted LH con-Te sec dose-response linkage. To this end, we measured LH and Te con every 10 min for 24 h in healthy young ( n = 13) and older men ( n = 13). Statistical comparisons of analytic estimates revealed that elderly subjects manifest 1) reduced maximal burstlike LH-stimulated Te sec (impaired stimulus efficacy); 2) depressed half-maximally LH-stimulated Te sec (lower Leydig-cell responsivity); 3) decreased pulsatile and total Te sec; 4) elevated basal Te sec; 5) a prolonged half-life of total but not free Te con; and 6) delayed time evolution of LH and Te sec bursts. In contradistinction, age did not influence estimated LH-pulse potency (ED50), steroidogenic sensitivity (slope term), or stochastic variability of LH-Te coupling. On the basis of these data, we postulate that aging in the human male alters specific dose-response attributes linking LH con and Te sec and disrupts the time waveform of LH and Te sec bursts.

Vesicoureteral Reflux in Asymptomatic Siblings of Patients With Known Reflux: Radionuclide Cystography

The familial nature of vesicoureteral reflux among siblings of patients with vesicoureteral reflux has been reported to be from 8% to 32%. These included both symptomatic and asymptomatic siblings. The incidence of vesicoureteral reflux in asymptomatic siblings, however, has not been studied extensively. Sixty asymptomatic siblings of patients known to have vesicoureteral reflux were studied with radionucide voiding cystography. Their ages ranged from 2 months to 15 years (mean, 4.2 years). Vesicoureteral reflux was detected in 27 of 60 (45%) of the siblings. Vesicoureteral reflux was unilateral in 15 and bilateral in 12 of the siblings. Radionucide cystography is more sensitive than radiographic cystography and results in a very low radiation dose to the patient. The gonadal dose with radionucide cystography is only 1.0 to 2.0 mrads. Because of these features, radionuclide cystography is a nearly ideal technique for the diagnosis of vesicoureteral reflux in siblings of patients with known vesicoureteral reflux. All siblings (symptomatic or asymptomatic) of patients with known vesicoureteral reflux should have a screening radionuclide cystography.