Differential Effects of Low and High Radiation Dose Rates on Mouse Spermatogenesis

The adverse effects of radiation are proportional to the total dose and dose rate. We aimed to investigate the effects of radiation dose rate on different organs in mice. The mice were subjected to low dose rate (LDR, ~3.4 mGy/h) and high dose rate (HDR, ~51 Gy/h) radiation. LDR radiation caused severe tissue toxicity, as observed in the histological analysis of testis. It adversely influenced sperm production, including sperm count and motility, and induced greater sperm abnormalities. The expression of markers of early stage spermatogonial stem cells, such as Plzf, c-Kit, and Oct4, decreased significantly after LDR irradiation, compared to that following exposure of HDR radiation, in qPCR analysis. The compositional ratios of all stages of spermatogonia and meiotic cells, except round spermatid, were considerably reduced by LDR in FACS analysis. Therefore, LDR radiation caused more adverse testicular damage than that by HDR radiation, contrary to the response observed in other organs. Therefore, the dose rate of radiation may have differential effects, depending on the organ; it is necessary to evaluate the effect of radiation in terms of radiation dose, dose rate, organ type, and other conditions.

Связь мощности дозы гамма-излучения с интенсивностью ливневых осадков

Experimental and theoretical studies of the influence of the intensity, amount and duration of liquid atmospheric precipitation on the formation of γ-background in the surface layer of the atmosphere are presented. It was observed that precipitation causes an increase in the γ-radiation dose rate in the form of bursts. In this case, the total amount of precipitation in an event determines the magnitude of the burst of the dose rate, and the intensity of precipitation determines the rate of increase in the dose rate of γ-radiation. A mathematical model, which establishes a quantitative relationship between the dose rate of γ-radiation and the intensity (amount) of liquid atmospheric precipitation has been developed and verified (R2 = 0.93). Представлены экспериментальные и теоретические исследования влияния интенсивности, количества и продолжительности жидких атмосферных осадков на формирование γ-фона в приземном слое атмосферы. Было замечено, что осадки вызывают увеличение мощности дозы γ-излучения в виде всплесков. В этом случае общее количество осадков в событии определяет величину всплеска мощности дозы, а интенсивность осадков определяет скорость увеличения мощности дозы γ-излучения. Разработана и проверена математическая модель, устанавливающая количественную связь между мощностью дозы γ-излучения и интенсивностью (количеством) жидких атмосферных осадков (R2 = 0,93).

Fully Vacuum-Sealed Diode-Structure Addressable ZnO Nanowire Cold Cathode Flat-Panel X-ray Source: Fabrication and Imaging Application

A fully vacuum-sealed addressable flat-panel X-ray source based on ZnO nanowire field emitter arrays (FEAs) was fabricated. The device has a diode structure composed of cathode panel and anode panel. ZnO nanowire cold cathodes were prepared on strip electrodes on a cathode panel and Mo thin film strips were prepared on an anode panel acting as the target. Localized X-ray emission was realized by cross-addressing of cathode and anode electrodes. A radiation dose rate of 10.8 μGy/s was recorded at the anode voltage of 32 kV. The X-ray imaging of objects using different addressing scheme was obtained and the imaging results were analyzed. The results demonstrated the feasibility of achieving addressable flat-panel X-ray source using diode-structure for advanced X-ray imaging.

Assessment of natural irradiation doses in rare earth mines of Muong Hum, Bat Xat district, Lao Cai province

The rare earth mine containing high concentrations of natural radionuclides (238U, 232Th, and 40K) in Muong Hum commune, Nam Pung, Bat Xat district, Lao Cai province, a mine with large reserves of rare earth resources in Vietnam, will be exploited and processed in the near future. The activity of natural radionuclides in the environment of air, soil, water, and effective annual dose are important parameters in assessing the impact of radiation on the environment when the mine goes into operating and processing rare earth ore. Investigating and determining radioactivity in soil, water, and plants at Muong Hum rare earth mine by means of radioactive gas measurement (RAD-7), gamma radiation dose rate (DKS-96), sample analysis using an ICP-MS mass spectrometer, will be performed in this study. The results showed that some soil samples had radionuclides activity 238U, 232Th higher than the allowed standard. The annual effective dose value in the region is 6.1 times higher than the world average (2.4 mSv/year). The obtained results are the basis for monitoring the impact of the radioactive environment and providing solutions to minimize the effects of radioactive substances on the ecological environment when the mine goes into mining and processing of rare earth ores.

Rainfall Intensity and Quantity Estimation Method Based on Gamma-Dose Rate Monitoring

The features of the atmospheric γ-background reaction to liquid atmospheric precipitation in the form of bursts is investigated, and various forms of them are analyzed. A method is described for interpreting forms of the measured γ-background response with the determination of the beginning and ending time of precipitation, the distinctive features of changes in the intensity of precipitation and the number of single (separate) events that form one burst. It is revealed that a change in the intensity of precipitation in one event leads to a change in the γ-radiation dose rate increase speed (time derivative). A method of estimating the average value of the intensity and amount of precipitation for one event, reconstructing the intensity spectrum from experimental data on the dynamics of the measured dose rate of γ-radiation, is developed. The method takes into account the radioactive decay of radon daughter products in the atmosphere and on the soil surface during precipitation, as well as the purification of the atmosphere from radionuclides. Recommendations are given for using the developed method to correct for changes (daily variations) in radon flux density from the ground surface, which lead to variations in radon in the atmosphere. Experimental verification of the method shows good agreement between the values of the intensity of liquid atmospheric precipitation, calculated and measured with the help of shuttle and optical rain precipitation gauges.

Model for Reconstruction of γ-Background during Liquid Atmospheric Precipitation

With regard to reconstructing the gamma background dose rate, existing models are either empirical with limited applicability or have many unknown input parameters, which complicates their application in practice. Due to this, there is a need to search for a new approach and build a convenient, easily applicable and universal model. The paper proposes a mathematical model for reconstructing the temporal evolution of the ambient equivalent γ-radiation dose rate during rain episodes, depending on the density of radon flux from the soil surface, as well as the duration and intensity of rain. The efficiency of the model is confirmed by the high coefficient of determination (R2 = 0.81–0.99) between the measured and reconstructed ambient equivalent dose rate during periods of rain, the simulation of which was performed using Wolfram Mathematica. An algorithm was developed for restoring the dynamics of the ambient equivalent γ-radiation dose rate during rainfall. Based on the results obtained, assumptions were made where the washout of radionuclides originates. The influence of the radionuclides ratio on the increase in the total γ-radiation dose rate was investigated.

ASSESSMENT OF RADIATION DOSE LEVEL AT KABBA COLLEGE OF AGRICULTURE, DIVISION OF AGRICULTURAL COLLEGES, AHMADU BELLO UNIVERSITY, ZARIA

Background radiation involves the measure of the level of ionizing radiation present in the environment at a particular location. This research seek to generate data of the natural background radiation level of some selected Sections at Kabba College of Agriculture, using RadEye G20 survey meter. A total of 15 sections of the College were randomly selected and the background radiation dose rate of the sections were measured. The indoor dose rate ranged from (0.09 – 0.13) 𝜇Sv/yr, while the outdoor dose rate ranged from (0.07 - 0.10) 𝜇Sv/yr. The indoor annual effective dose were observed to be greater than the outdoor annual effective dose in all the College Sections measured. The lowest total annual effective dose 0.75 𝑚𝑆𝑣/𝑦𝑟 was found at the Academic staff block. The highest total annual effective dose of 1.09 𝑚𝑆𝑣/𝑦𝑟 was found at the livestock building, this might be due to the high-altitude nature of the area and the rocky materials used in the construction of the building. The highest total annual effective dose of the study area was slightly above the recommended limit of 1.0 𝑚𝑆𝑣/𝑦𝑟. The result obtained from this research may not constitute immediate health risk to the staff and student of the college