Adjustable hollow-cone output x-ray beam from an ellipsoidal monocapillary with a pinhole and a beam stop.

A combined shading system (CSS) consisting of a beam stop and a pinhole is proposed to be used between an ellipsoidal monocapillary (EM) and a conventional laboratory x-ray source to obtain an adjustable hollow-cone output beam for different experiments with no need for changing the EM. The CSS can change the incident x-ray beam on the EM by adjusting the position of the beam stop and the pinhole, with the corresponding change of the output beam of the EM. In this study, the adjustable hollow-cone output x-ray beam of an 80-mm-long EM with a CSS was studied in detail with a laboratory Cu x-ray generator with a focal spot diameter of 50 µm. The adjustable range of the focal spot size of the EM was from 8.6 to 58.7 µm. The adjustable range of the gain of the focal spot of the EM was from 0 to 1350. The beam divergence of the hollow-cone output beam of the EM ranged from 6 to 16.75 mrad. The illumination angle of the hollow-cone output beam of the EM ranged from 0 to 5.95 mrad. In addition, the potential application of the proposed adjusting method in testing the performance of the EM is briefly discussed.

Spatially resolved in situ measurements of the ion distribution near the surface of electrode in a steady-state diffusion in an electrolytic tank with confocal micro X-ray fluorescence.

Confocal micro-X-ray fluorescence (MXRF) technology based on a polycapillary focusing X-ray lens and a polycapillary parallel X-ray lens was used to carry out element-resolved and in situ analysis of ion distribution near the surface of the electrode in a steady-state diffusion in an electrolytic tank. The standard curve of the Cu Kα fluorescence intensity corresponding to the concentration of CuCl2 was measured to quantitatively determine the ion distribution near the surface of the electrode in a steady-state diffusion. The distribution of the electrolytic ions around the surface of the electrode in the electrolytic tank was measured in situ, and the effects of the concentration of the electrolyte and the bath voltage on the shape of the layer with a nonuniform distribution of the Cu(2+) ions near the cathode surface in a steady state were analyzed with the confocal MXRF. The confocal MXRF has potential applications in spatially resolved analysis of the liquid mass transfer in electrolytic tanks in situ.

Analysis and Monitoring of Indoor Radon Concentrations of 37 Kindergartens - Beijing Municipality, China, 2023.

Introduction: Radon (222Rn or 222radon) is a radioactive gas emitted from building materials, foundations, and soil. Children are especially susceptible to radon exposure, underscoring the need to assess indoor radon levels in kindergartens. This study monitored radon concentrations in 37 Beijing kindergartens from June to October 2023. Methods: A random sample of 37 kindergartens was selected from 18 administrative districts in Beijing. The indoor radon concentration was measured using the solid track accumulation method, with radon detectors continuously monitored over a 3-month period. Results: The mean indoor radon level in 37 kindergartens, observed at 252 monitoring points, was 84.3 Bq/m3, with values varying from 12.9 to 263.5 Bq/m3. About 20.2% of points showed radon levels between 100.0 and 200.0 Bq/m3, while 2.4% exceeded 200.0 Bq/m3. Notably, radon levels were significantly elevated on the ground floor compared to the upper floors. Conclusion: Indoor radon levels in 37 kindergartens remained below the national standard limit of 300.0 Bq/m3 for buildings (GB/T 16146-2015). Nonetheless, 18.9% of the kindergartens exceeded the 100.0 Bq/m3 limit set for new constructions. It is advised to improve radon monitoring in kindergartens and consider developing a national standard for maximum permissible radon levels in such facilities.

Survey on radioactive contamination in Beijing following the Japanese Fukushima nuclear accident.

The radioactive contamination in Beijing caused by the Japanese Fukushima nuclear accident was monitored. In this research, samples of air, rainwater, surface water and vegetables in Beijing were collected and measured to estimate the radioactive contamination levels in Beijing. During the period from the 15th to the 41st day after the first emission of radioactive material (first emission) from the Japanese Fukushima nuclear power station (NPS) on 12 March 2011, obvious radioactive contamination was found in the Beijing air samples. The maximum concentration of I-131 was 5.89 mBq m(-3) in the air samples detected on the 22nd day after the first emission, and the maximum concentration of Cs-137 and Cs-134 was found on the 20th day after the first emission. Except for one sample of rainwater, no artificial radionuclides associated with Fukushima were found in surface water. The measurement results showed that there was no harm to the health of local Beijing residents.

What happened when medical staff in Beijing, China wore over-apron dosemeters?

The wearing method of personal dosemeters for medical staff changed from under to outside the operator's protective apron in April 2020. We measured the radiation dose Hp(10) for medical staff in Beijing from September 2020 to October 2021. The study population consisted of 3291 medical staff. All participants were divided into three groups. After excluding unusually low doses, the collected data higher than the detection limit involved 811 (7.8%) of 10 395 readings from 479 (14.6%) of 3291 staff. The mean equivalent dose was 1.4 mSv/3 months, with an SD of 2.3 mSv. The calculated average annual effective doses of radiation workers in the three groups after the interventional procedures from September 2020 to October 2021 ranged from 0.47 to 0.63 mSv/year, with median values of 0.32, 0.23 and 0.26 mSv/year, respectively.

Temporal variations of 7Be and 210Pb activity concentrations in the atmospheric aerosols during 2018-2019 in Beijing, China and their correlations with meteorological parameters.

In order to establish a regional database on natural radioactivity, a series of measurements of 713 atmospheric aerosol samples collected on filters over a two-year period (2018-2019) in center of Beijing, northeastern China have been performed to analyze 7Be and 210Pb activity concentrations. The mean activity concentrations of 7Be and 210Pb were found to be 7.10 ± 2.44 mBq m-3 and 2.93 ± 1.52 mBq m-3, respectively. Both the radionuclides exhibited strong seasonal variations, with maximum concentration of 7Be occurring in the spring and that of 210Pb in the winter. The concentration of both the radionuclides was minimum in the rainy summer. Higher 7Be concentration in the spring was mainly caused by the stratosphere to troposphere exchange. Higher 210Pb concentration during winter was maybe attributed to the combustion processes in heating systems and the ingression of continental air masses resulted from winds originating from northwest. The dependence of the activity concentrations of 7Be and 210Pb with meteorological parameters such as rainfall, temperature, and humidity was studied through linear correlation analysis. Statistically significant negative correlations were observed between 7Be and 210Pb activity concentrations with rainfall, respectively, which suggested that the removal mechanisms of these two radionuclides were similar. Lead-210 showed statistically significant correlations with temperature, humidity and PM10. A comparison of the data obtained in the present study for Beijing with the northern hemisphere literature values of 7Be and 210Pb in the atmospheric aerosols showed that the values were smaller than the ones observed in the present study. Overall, the study provides an improved understanding of the temporal variability and correlation of 7Be and 210Pb concentrations in the atmosphere in center of Beijing, northeastern China.

Chemical content and source apportionment of 36 heavy metal analysis and health risk assessment in aerosol of Beijing.

The concentration levels of 36 airborne heavy metals and atmospheric radioactivity in total suspended particulate (TSP) samples were measured to investigate the chemical characteristics, potential sources of aerosols, and health risk in Beijing, China, from September 2016 to September 2017. The TSP concentrations varied from 6.93 to 469.18 µg/m3, with a median of 133.97 µg/m3. The order for the mean concentrations of heavy metals, known as hazardous air pollutants (HAPs), was as follows: Mn > Pb > As > Cr > Ni > Se > Cd > Co > Sb > Hg > Be; Non-Designated HAPs Metals: Ca > Fe > Mg > Al > K > Na > Zn > P > Ba > Ti > Cu > Sr > B > Sn > I > V > Rb > Ce > Mo > Cs > Th > Ag > U > Pt. The median concentration of As was higher than China air quality standard (6 ng/m3). The gross α and ß concentration levels in aerosols were (1.84 ± 1.59) mBg/m3 and (1.15 ± 0.85) mBg/m3, respectively. The enrichment factor values of Cu, Ba, B, Ce, Tl, Cs, Pb, As, Cd, Sb, Hg, Fe, Zn, Sn, I, Mo, and Ag were higher than 10, which indicated enriched results from anthropogenic sources. Pb, As, and Cd are considered to originate from multiple sources; fireworks released Ba during China spring festival; Fe, Ce, and Cs may come from stable emissions such as industrial gases. The health risks from anthropogenic metals via inhalation, ingestion, and dermal pathway were estimated on the basis of health quotient as well as the results indicated that children faced the higher risk than adults during the research period. For adults, the health risk posed by heavy metals in atmospheric particles was below the acceptable level.

In-situ and elementally resolved determination of the thickness uniformity of multi-ply films by confocal micro XRF.

Confocal micro X-ray fluorescence (CM-XRF) with quasi-monochromatic excitation based on polycapillary X-ray optics was used to measure the thickness of multi-ply films. The relative errors of measuring an Fe film with a thickness of 16.3 µm and a Cu film with a thickness of 24.5 µm were 7.3% and 0.4%, respectively. The non-destructive and in-situ measurement of the thickness and uniformity of multi-ply films of Cu, Fe and Ni on a silicon surface was performed. CM-XRF was convenient in in-situ and elementally resolved analysis of the thickness of multi-ply films without a cumbersome theoretical correction model.

Radon concentrations in drinking water in Beijing City, China and contribution to radiation dose.

(222)Rn concentrations in drinking water samples from Beijing City, China, were determined based on a simple method for the continuous monitoring of radon using a radon-in-air monitor coupled to an air-water exchanger. A total of 89 water samples were sampled and analyzed for their (222)Rn content. The observed radon levels ranged from detection limit up to 49 Bq/L. The calculated arithmetic and geometric means of radon concentrations in all measured samples were equal to 5.87 and 4.63 Bq/L, respectively. The average annual effective dose from ingestion of radon in drinking water was 2.78 µSv, and that of inhalation of water-borne radon was 28.5 µSv. It is concluded that it is not the ingestion of waterborne radon, but inhalation of the radon escaping from water that is a substantial part of the radiological hazard. Radon in water is a big concern for public health, especially for consumers who directly use well water with very high radon concentration.

Application of confocal X-ray fluorescence micro-spectroscopy to the investigation of paint layers.

A confocal micro X-ray fluorescence (MXRF) spectrometer based on polycapillary X-ray optics was used for the identification of paint layers. The performance of the confocal MXRF was studied. Multilayered paint fragments of a car were analyzed nondestructively to demonstrate that this confocal MXRF instrument could be used in the discrimination of the various layers in multilayer paint systems.

[Expression of SOX2 protein and its clinical significance in laryngeal carcinoma].

OBJECTIVE: To investigate the expression of SOX2 in laryngeal carcinoma and analyze the relation of SOX2 and clinical factors. METHOD: We measured the expression of SOX2 protein in 45 laryngeal carcinoma fresh samples and 45 paracarcinoma tissues (cutting margin > 0.5 cm) with flow cytometer (Epics-XL II), 20 normal laryngeal mucosa samples were also studied as controls. RESULT: The quantitative and qualitative expression of SOX2 protein in laryngeal carcinoma tissues was obviously higher than those in paracarcinoma and in normal laryngeal mucosa tissues respectively (P < 0 05). There was no significant difference between the expression of paracarcinoma and normal laryngeal mucosa tissues. In laryngeal carcinoma, the expression of SOX2 protein wasn't significantly related to patients' clinical classification, tumor size, smoking history, patients' age and sex but related to metastasis, pathological grade and clinical stage. CONCLUSION: The high expression of SOX2 may contribute to the carcinogenesis and development of laryngeal carcinoma. It is an important index of judging metastasis and staging and prognosis of laryngeal carcinoma to measure the expression of SOX2 protein.

Focusing synchrotron radiation using a polycapillary half-focusing X-ray lens for imaging.

An imaging system based on a polycapillary half-focusing X-ray lens (PHFXRL) and synchrotron radiation source has been designed. The focal spot size and the gain in power density of the PHFXRL were 22 microm (FWHM) and 4648, respectively, at 14.0 keV. The spatial resolution of this new imaging system was better than 5 microm when an X-ray charge coupled device with a pixel size of 10.9 x 10.9 microm was used. A fossil of an ancient biological specimen was imaged using this system.