[en] To study the influence of the geometric position of the actual sample and the geometry of the sample on the measurement of the anti-Campton gamma spectrometer, the Compton suppression effect of an anti-Campton γ spectrometer system was tested by changing the position between the source and primary detector or plug detector and the geometry of the source itself. When the source is located at the surface of the primary detector and the plug detector is close to the point source, the peak-to-Compton ratio (P/C) and Compton-suppressed factor (CSF) can reach the maximum; The P/C and CSF are smaller when the volume source have the same diameter and smaller height or when the volume source have the same height and smaller diameter. Among the ⁴⁰K volume source which was tested, the volume source of Φ 30 mm × 15 mm has the largest P/C and CSF value; the volume source of Φ 75 mm × 20 mm has comparatively large P/C and CSF value, and can load more sample. The Compton-suppressed effect can be better by changing the geometric position and geometry of the actual sample. (authors)

[en] By using MCNP simulation and measurement, the source terms and the influence factors to its field strength was researched for the machine hall of high frequency and high voltage electron irradiation accelerator. The results show that the source terms in machine hall mainly come from the scattering irradiation after electrons shooting the target in radiation room. The radiation field intensity in the machine hall is determined by the sizes of the pipe hole between the machine hall and radiation room, and the thicknesses of shielding material in the pipe hole. (authors)

[en] Spatio-temporal evolutions of the sawteeth activities are measured simultaneously with a 16 channel high spatio-temporal resolution electron cyclotron emission (ECE) heterodyne radiometer on HT-7 and the evolutions of the sawteeth are found to be diffusive in character. By a perturbative analysis, the electron heat diffusivity χ_e inferred by time-to-peak method and Fourier transform shows a good agreement. The value of electron heat diffusivity shows radial asymmetry between the low magnetic field side (LFS) and the high magnetic field side (HFS). It is observed that with the increase in plasma density, the electron heat diffusivity decreases and the confinement of energy is improved. By comparing with χ^pb_e inferred by static power balance analysis, the result indicate that χ^hp_e is larger than χ^pb_e by a factor ranging from 2 to 10. (magnetically confined plasma)

[en] Objective: This study focuses on the annual variation of the concentration of radionuclides ⁷Be and ²¹⁰Pb in TSP and PM_2.5 in Hefei and relationship between activity concentration and mass concentration of particle matter. Methods: TSP and PM_2.5 samples of the same period of each month in Hefei were collected by large-flow aerosol sampler and PM_2.5 particle size cutter, respectively. The activity concentrations of ⁷Be and ²¹⁰Pb in samples were measured by the ultra-low background HPGe spectrometer. Results: The results showed that the annual averaged values of the activity concentrations of ⁷Be and ²¹⁰Pb in TSP samples were (5.34 ± 1.48) mBq/m³ and (1.66 ± 0.84) mBq/m³, respectively. The annual averaged values of the activity concentrations of ⁷Be and ²¹⁰Pb in PM_2.5 samples were (4.32 ± 1.23) mBq/m³ and (1.35 ± 0.68) mBq/m³, respectively. The ratio of the monthly averaged value of the activity concentrations of ⁷Be and ²¹⁰Pb in PM_2.5 and TSP ranged from 0.59 to 0.99, and 0.61 to 0.94, respectively; The annual variation trends of ⁷Be and ²¹⁰Pb activity concentrations in TSP and PM_2.5 were basically consistent with the annual variation trend of mass concentration of particulate matter, showing high in winter and spring seasons and relatively low in summer and autumn seasons. However, the specific activities of ⁷Be and ²¹⁰Pb in TSP and PM_2.5 had no significant correlation with the mass concentration of particulate matter. Conclusion: The activity concentrations of ⁷Be and ²¹⁰Pb in the TSP and PM_2.5 in Hefei mainly depend on mass concentration of particle matter, and the ⁷Be and ²¹⁰Pb in the atmospheric particulate matter are mainly distributed in PM_2.5. Therefore, further study should mainly consider the contribution of radioactive particles in PM_2.5 when assessing the hazards of radioactive particulate matter in the atmosphere to humans. (authors)

[en] In general, the content of ²²⁶Ra in a sample is deduced from results of ²²²Rn progeny in HPGe γ spectral analysis. Because the sample should be sealed for several weeks before the measurement, we can not get the results quickly through this method. The paper analyzes the source of the counts of the full-energy peak in 186 keV in the full-energy peak, and modifies the result of ²²⁶Ra content calculated by using the full-energy peak in 186 keV. The study gets good experiment results and realizes the rapid measurement of Ra in samples using the full-energy peak in 186 keV. (authors)

[en] Objective: To investigate and study the radioactivity levels in the process of mining and utilization of stone coals in southern Anhui, and evaluate its impact on the surrounding environment and residents' dose. Methods: By taking the stone coal mine, stone coal derivative products and surrounding environment in the typical stone coal mine area of southern Anhui as the research object, the relevant data were monitored on-site or through laboratory analysis. Results: The highest contents of ²³⁸U, ²²⁶Ra and ²¹⁰Pb in stone coal mines were up to 1298 Bq/kg, 1598 Bq/kg and 1212 Bq/kg, respectively. It belongs to the category of associated radioactive minerals. Having been burned, the concentration of ²¹⁰Pb in the coal slag was generally reduced. The contents of some natural radionuclides in the soil and water samples around the mining area were much higher than the average level of the surveyed area. The annual effective dose per capita of external radiation in the stone coal carbide brick building was estimated to be 1.01 ∼ 1.24 mSv, and the annual effective dose due to inhalation of ²²²Rn and its progeny was 1.8 ∼ 4.9 mSv. Conclusion: The natural radionuclides in the stone coal have been partially transferred to the surrounding soil and water. The annual additional effective dose of residents living or working in carbonized brick houses has significantly increased. (authors)

[en] Slide-away discharges are achieved by decreasing the plasma density or ramping down the plasma current in runaway discharges in the HT-7 tokamak. In the case of plasma current ramp down, the ratio of the electron plasma frequency to the electron cyclotron frequency is higher than in the stationary pulses when the discharge goes into a slide-away regime. The instability regime is characterized by relaxations in the electron cyclotron emission due to relativistic anomalous Doppler effect which transfers energy from parallel to perpendicular motion. The triggering of relativistic anomalous Doppler effect at higher density by ramping down of plasma current may provide a alternative runaway energy control scenario. (authors)

[en] Objective: To measure the spatial distribution of radiation field and how it changes over time in the process of therapy thyroid carcinoma with ¹³¹I, and also to offer a meaningful reference for the shielding design of ward and radiation environment management of related projects. Methods: Active measurement combining with the passive measurement. Results: The radiation dose rate of the position 1 meter in front of the patients' chest reached 393 μGy/h after taking the drug for 5 minutes. And the dose rate attenuated significantly with the increase of treatment time. During the whole treatment, the cumulative dose generated from patients to the nearest monitoring point was 2.6 mSv. For each cumulative dose monitoring points in the ward, dose generated in the first 24 hours was 57%∼80% of the total dose generated in the entire treatment process; dose generated in the first 48 hours accounted for 80%∼95%; but the dose later only contributed a little part to the total dose. Conclusion: The measurement results have a good reflection of the source intensity and distribution of the radiation field in the whole ¹³¹I therapy for differentiated thyroid carcinoma metastases. (authors)

[en] In the paper, some corrections of γ nuclide analyzing result for Fukushima nuclear accident emergency monitoring aerosol sample were presented according to sum-up of emergency monitoring work. The analyzing result of short half-life nuclide samples, especially for the samples needed long time to collect and measure, need be corrected owing to decay. The collecting time correction, laying time correction and measuring time correction factors were given. The filtration efficiency correction need be considered when the radioactive nuclide activity concentration in aerosol sample was analyzed. The filtration efficiencies of two kinds of common filters were given by using the method of double filters in this paper. The method of analyzing radioactive nuclide ¹³⁷Cs in aerosol, whose γ ray spectrum is interfered, was introduced, and the means of depressing interference peak for aerosol sample were presented. The method of γ nuclide analyzing result correction for aerosol sample can provide reference for nationwide nuclear accident emergency monitoring. (authors)

[en] Highlights: • Gab2 promotes the growth of CSC-like population of ovarian cancer cells. • Gab2 promotes metastatic growth of ovarian cancer cells in xenograft. • Gab2 via PI3K inhibits miR-200c expression in ovarian cancer cells. • Gab2 via miR-200c downregulation promotes phenotypes of EMT and CSC. • Gab2 inhibition of miR-200c enhances CD44 expression and cell migration/invasion. -- Abstract: Scaffolding adaptor Gab2 is overexpressed in a subset of high-grade ovarian cancer. Our published work shows that Gab2 via PI3K enhances migratory behaviors and epithelial to mesenchymal transition (EMT) features of ovarian cancer cells in vitro. However, it is still unclear how Gab2/PI3K pathway reuglates EMT characteristics and whether Gab2 promotes the growth of ovarian cancer stem cell (CSC)-like population and metastatic growth. In this study, we examined the effects of Gab2 expression on CSC-like cell growth using Aldefluor and tumorshpere assays commonly used for assessing ovarian cancer cells with CSC properties. Gab2 overexpression increased the number of ALDH⁺ cells and tumorsphere formation in two different ovarian cancer cell lines OVCAR5 and OVCAR8, whereas knockdown of Gab2 decreased the number of ALDH⁺ cells and tumorsphere formation in Caov-3 cells. Furthermore, Gab2 promoted metastatic tumor growth of OVCAR5 in nude mice. Mechanistically, we uncovered that Gab2 via PI3K specifically inhibited miR-200c expression. miR-200c downregulation contributed to the Gab2-enhanced cell migratory behaviors, EMT properties, and the expansion of ALDH⁺ cells and tumorspheres. Furthermore, Gab2 promoted CD44 expression and cell migration/invasion through miR-200c downregulation. Our findings support a model that Gab2-PI3K pathway via miR-200c downregulation promotes CD44 expression, EMT characteristics, and CSC-like cell growth. Therapies involving miR-200c or targeting CD44 should help treat ovarian cancer with high Gab2 expression.