Numerical Simulation on Radon Retardation Behavior of Covering Floats in Radon-Containing Water

Objective This study aimed to efficiently reduce the release of radon from water bodies to protect the environment.Methods Based on the sizes of the experimental setup and modular float,computational fluid dynamics(CFD)was used to assess the impact of the area coverage rate,immersion depth,diffusion coefficient,and radon transfer velocity at the gas–liquid interface on radon migration and exhalation of radon-containing water.Based on the numerical simulation results,an estimation model for the radon retardation rate was constructed.The effectiveness of the CFD simulation was evaluated by comparing the experimental and simulated variation values of the radon retardation rate with the coverage area rates.Results The effect of radon transfer velocity on radon retardation in water bodies was minor and insignificant according to the appropriate value;therefore,an estimation model of the radon retardation rate of the coverage of a radon-containing water body was constructed using the synergistic impacts of three factors:area coverage rate,immersion depth,and diffusion coefficient.The deviation between the experimental and simulated results was<4.3%.Conclusion Based on the numerical simulation conditions,an estimation model of the radon retardation rate of covering floats in water bodies under the synergistic effect of multiple factors was obtained,which provides a reference for designing covering floats for radon retardation in radoncontaining water.

Performances of different efficiency calibration methods of high-purity-germanium gamma-ray spectrometry in an inter-comparison exercise

This study reports the performances of efficiency calibrations for high-purity-germanium gamma-ray spectrometry using the source-, Laboratory Sourceless Object Calibration Software(LabSOCS)-and ANGLE-based methods in an inter-comparison exercise. Although the results of LabSOCS and ANGLE for ^(241)Am emitting lowenergy gamma rays were not very satisfactory, all of the three efficiency calibration methods passed acceptance criteria. The results confirmed the reliability of the calculation codes ANGLE and LabSOCS as alternative efficiency calibration methods in high-purity-germanium gamma spectrometry. This study is likely to promote the further application of the ANGLE and LabSOCS calculation codes in radioactivity measurements.

Identification and Validation of Candidate Radiation-responsive Genes for Human Biodosimetry

The aim of the present study is to analyze the global research trend of radiation-responsive genes and identify the highly reproducible radiation-responsive genes. Bibliometric methods were applied to analyze the global research trend of radiation-responsive genes. We found 79 publications on radiation-responsive genes from 2000 to 2017. A total of 35 highly reproducible radiation-responsive genes were identified. Most genes are involved in response to DNA damage, cell proliferation, cell cycle regulation, and DNA repair.The p53 signal pathway was the top enriched pathway. The expression levels of 18 genes in human B lymphoblastoid cell line（AHH-1） cells were significantly up-regulated in a dose-dependent manner at 24 h after exposure to 0-5 Gy ^60 Coγ-ray irradiation. Our results indicate that developing a gene expression panel with the 35 high reproducibility radiation-responsive genes may be necessary for qualitative and quantitative assessment after exposure.

Facile Synthesis of the Magnetic Metal Organic Framework Fe_3O_4@UiO-66-NH_2 for Separation of Strontium

A magnetic metal organic framework（MMOF） was synthesized and used to separate Sr^2＋ in aqueous solution. The shape and structure of prepared Fe3O4@UiO-66-NH2 were characterized, and the absorbed concentration of strontium was determined through inductively coupled plasma mass spectrometry. The results indicated that Fe3O4 and UiO-66-NH2 combined through chemical bonding. The experimental adsorption results for separation of Sr^2＋ in aqueous solution indicated that the adsorption of Sr^2＋ to Fe3O4@UiO-66-NH2 increased drastically from pH 11 to pH 13. The adsorption isotherm model indicated that the adsorption of Sr^2＋ conformed to the Freundlich isotherm model（R2 = 0.9919）. The MMOF thus inherited the superior qualities of magnetic composites and metal organic frameworks, and can easily be separated under an external magnetic field. This MMOF thus has potential applications as a magnetic adsorbent for low level radionuclide （90）Sr.

Synthesis of TBP-coated magnetic Pst-DVB particles for uranium separation

Magnetically assisted chemical separation process is an efficient method used widely in separating radionuclides and heavy metals in environmental samples. It is simple, compact and cost-effective, with less secondary waste streams. Tributyl phosphate(TBP)-coated magnetic poly(styrene-divinylbenzene)(Pst-DVB)nano-particles were synthesized and characterized by transmission electron microscopy, scanning electron microscopy, vibrating sample magnetometer, thermogravimetry and Fourier transform infrared spectrometry. The application of TBP-coated magnetic Pst-DVB particles in separating low concentration of uranium from aqueous media was evaluated, and the equilibrium adsorption isotherm was investigated. Our results indicate that the TBP-coated magnetic Pst-DVB particles may be of potential application for uranium separation.

<i>STYK1/NOK</i>—A Potential Radiotherapeutic Target and Biomarker for Gastric Cancer and Cervical Cancer

This article introduced the STYK1/NOK, including its origin, chemical composition and biological function, and the expression of STYK1/NOK in various cancer cell lines was reviewed. Furthermore, our recent study showed that STYK1/NOK protein was also over expressed in gastric cancer and cervical cancer specimens, and STYK1/NOK expression increased after tumor cells were irradiated with γ ray. These results indicated that STYK1/NOK might be involved in the occurrence and progress of gastric cancer and cervical cancer, and contribute to the radioresistance of tumor cells. Thus, STYK1/NOK might be a potential therapeutic target and diagnostic marker for gastric cancer and cervical cancer.

Validation and Comparison of Two Calibration Methods for the Measurement of Stable Iodine in the Urinary Matrix by ICP-MS:Standard Addition vs.External Calibration

Background: In the context of a nuclear reactor accident, thyroid is the main target organ of radioactive iodines. To avoid as much as possible thyroid disorders or even cancer development, it is recommended to administer a single dose of potassium iodide to people at risk of exposure. Nevertheless, the Fukushima Dai-ichi disaster has pointed out many questions about the conditions of stable iodine prophylaxis implementation highlighting the need for reflection further revision of the actual “iodine doctrine”. Therefore, providing useful data is required notably through the implementation of animal experiments to strengthen current knowledge and to edit new recommendations. Methods: Urinary iodine constitutes a very good indicator to investigate the function of thyroid, its interpretation demands reliable analyses. Prior to perform animal experiments, two calibration methods were designed by our lab and compared together (standard addition and external calibration) to assess the urinary concentration of stable iodine in urine by ICP-MS. They were validated based on several key parameters especially linearity, accuracy and limits of detection (LOD) and quantification (LOQ). Results: The results were nicely satisfying. Indeed, both calibration methods have indicated very good coefficients of correlations, accuracies with low expanded relative uncertainties were obtained. The estimated LOD in the sample for standard addition method and external calibration were fully acceptable, 0.39 μg·L-1 and 0.35 μg·L-1, respectively. All performance criteria have been thus fulfilled successfully. The established methods were proven to be accurate, robust and sensitive. Once validated, both calibration methods were applied to rat urine samples and the results of z-score and Wilcoxon W test concluded that there were no statistically significant differences between both methods.

Measurement of^(134)Xe(n,2n)^(133m),gXe reaction cross sections in 14‑MeV region with detailed uncertainty quantification

A lead-shielded HPGe detector and offlineγ-ray spectra of the residual product were used to measure the cross section(CS)and ratios of isomeric CS(σm/σg)in^(134)Xe(n,2n)^(133m),gXe reactions at different energies(13.5 MeV,13.8 MeV,14.1 MeV,14.4 MeV,14.8 MeV)relative to the^(93)Nb(n,2n)^(92)mNb reaction CS.The target was high-purity natural Xe gas under high pressure.The T(d,n)4He reaction produces neutrons.TALYS code(version 1.95)for nuclear reactions was used for calculations,with default parameters and nuclear level density models.The uncertainties in the measured CS data were thoroughly analyzed using the covariance analysis method.The results were compared with theoretical values,evaluation data,and previous experimental findings.CS data of the 134Xe(n,2n)133mXe and 134Xe(n,2n)133gXe reactions and the corresponding isomeric CS ratios at 13.5 MeV,13.8 MeV,and 14.1 MeV neutron energies are reported for the first time.This research advances our knowledge of pre-equilibrium emission in the(n,2n)reaction channel by resolving inconsistencies in the Xe data.

ICP-MS measurement of uranium and thorium contents in minerals in China

The activity levels of long-lived radionuclides in minerals have received more and more concern for the public health. The inductively coupled plasma mass spectrometry was used to measure the content of uranium and thorium in 60 mineral samples collected from 16 mines of seven provinces in China. The contents of uranium and thorium ranged0.17 ± 0.04 lg g^(-1)to 15.3 ± 2.39 lg g^(-1), and 0.19 ± 0.04 lg g^(-1)to 19.6 ± 7.56 lg g^(-1), respectively. The highest levels of U and Th contents were found in aluminum ore,whereas the lowest was found in antimony and copper ores.

Bridging peripheral nerves using a deacetyl chitin conduit combined with short-term electrical stimulation

Previous studies have demonstrated that deacetyl chitin conduit nerve bridging or electrical stimulation can effectively promote the regeneration of the injured peripheral nerve. We hypoth-esized that the combination of these two approaches could result in enhanced regeneration. Rats with right sciatic nerve injury were subjected to deacetyl chitin conduit bridging combined with electrical stimulation （0.1 ms, 3 V, 20 Hz, for 1 hour）. At 6 and 12 weeks after treatment, nerve conduction velocity, myelinated axon number, ifber diameter, axon diameter and the thickness of the myelin sheath in the stimulation group were better than in the non-stimulation group. The results indicate that deacetyl chitin conduit bridging combined with temporary electrical stimu-lation can promote peripheral nerve repair.

Connexin43 Modulates X-Ray-Induced Pyroptosis in Human Umbilical Vein Endothelial Cells

Objective Pyroptosis is an inflammatory form of programmed cell death. This phenomenon has been recently reported to play an important role in radiation-induced normal tissue injury. Connexin43(Cx43) is a gap junction protein that regulates cell growth and apoptosis. In this study, we investigated the effect of Cx43 on X-ray-induced pyroptosis in the human umbilical vein endothelial cells(HUVECs). Methods HUVECs, Cx43 overexpression, and Cx43 knockdown strains were irradiated with 10 Gy. Proteins were detected using western blot analysis. Cell pyroptosis was evaluated using the fluorescence-labeled inhibitor of caspase assay(FLICA) and propidium iodide staining through flow cytometry and confocal microscopy. Cell morphology and cytotoxicity were detected by scanning electron microscopy and lactate dehydrogenase release assay, respectively. Results Irradiation with 10 Gy X-ray induced pyroptosis in the HUVECs and reduced Cx43 expression. The pyroptosis in the HUVECs was significantly attenuated by overexpression of Cx43 as it decreased the level of active caspase-1. However, interference of Cx43 expression with si RNA significantly promoted pyroptosis by increasing the active caspase-1 level. Pannexin1(Panx1), a gap junction protein regulates pyroptosis, and its cleaved form is used to evaluate channel opening and active state. The level of cleaved Panx1 in the HUVECs and Cx43 knockdown strains increased in the presence of X-ray, but decreased in the Cx43 overexpression strains. Furthermore, interference of Panx1 with si RNA alleviated the upregulation of pyroptosis caused by Cx43 knockdown. Conclusion Results suggest that single high-dose X-ray irradiation induces pyroptosis in the HUVECs. In addition, Cx43 regulates pyroptosis directly by activating caspase-1 or indirectly by cleaving Panx1.

Determination of Trace Elements in Edible Nuts in the Beijing Market by ICP-MS

Nuts have received increased attention from the public in recent years as important sources of some essential elements, and information on the levels of elements in edible nuts is useful to consumers. Determination of the elemental distributions in nuts is not only necessary in evaluating the total dietary intake of the essential elements, but also useful in detecting heavy metal contamination in food. The aim of this study was to determine the mineral contents in edible nuts, and to assess the food safety of nuts in the Beijing market. Levels of Li, Cr, Mn, Co, Cu, Zn, As, Se, Rb, Sr, Mo, Cd, Cs, Ba, Pb, Th, and U in 11 types of edible nuts and seeds （macadamia nuts, lotus nuts, pistachios, sunflower seeds, pine nuts, almonds, walnuts, chestnuts, hazelnuts, cashews, and ginkgo nuts） as well as raisins were determined by inductively coupled plasma mass spectrometry （ICP-MS）. The accuracy of the method was validated using standard reference materials GBWlO014 （cabbage） and GBWlO016 （tea）. Our results provide useful information for evaluating the levels of trace elements in edible nuts in the Beijing market, will be helpful for improving food safety, and will aid in better protecting consumer interests.

Experimental investigation on the radiation background inside body counters

In vivo measurement of radioactivity based on various body counters is arguably the leading measure used to determine the distribution and activity of radionuclides in human subjects,such as I-131 in the thyroid,Am-241 in the lungs,and Pb-210 in the skull.Throughout the measurements,the radiation background is the key factor that determines the sensitivity of the counter.Therefore,to facilitate in vivo measurements,a well-designed shielding room is required to create a low-background environment.However,because the compositions of the radiation background are quite complicated,the respective contributions from each source remain obscure,which places a considerable burden on seeking an optimized design of shielding rooms that strikes the optimum balance between the construction cost and background suppression effect.In this study,we conducted a systematic experimental investigation on the radiation background outside and inside four representative body counters with assorted designs using a variety of radiation detectors,including high-purity germanium detectors,CdZnTe detector,radon emanometer,and gamma-ray dosimeter.By carefully controlling the experimental conditions and synergetic analysis of the measurement results,in conjunction with previous studies,we separated and determined the relative contributions induced by environmental radiation(4%),airborne radon and its daughters(2%),the normal radioactivity of human subjects arising from K-40(58%),cosmic rays(12%),and radioactivity in shielding materials and measuring instruments(24%).Furthermore,based on these results,we discuss practical guidelines to design a shielding room for body counters.

Cloning, characterization and expression analysis of a microsomal glutathione S-transferase gene from the seagrass Zostera marina

The response of glutathione S-transferase(GST)in Zostera marina to temperature variation was analyzed at molecular level by cloning the microsomal GST gene and texting the microsomal GST expression regularity under different temperature.Specific speaking,express ZmGST in Escherichia coli,then purify the recombinant protein and make the thermal stability analysis.Therefore,the experiments were carried out to provide a theoretical basis for the further elaboration to the population degradation mechanisms of Z.marina.In conclusion,the thermostability and the response of ZmGST gene to temperature changes can determine its temperature tolerance range,and affect its resilience in turn.

Crustaceous lichens sensitive monitor of caesium-137 radiation level in terrestrial environment

The activity of caesium-137 （Bq/kg） in the crustaceous lichens and other samples was determined to prove the feasibility that crustaceous lichens work as a sensitive biology monitor to record the caesium-137 （Bq/kg） radiation levels of terrestrial environment. The measurements were performed with GEM series HPGe （ high-purity Germanium） coaxial detector system （ADCAM -100 ） made by EC ＆ GORTEC Company in USA. It was found that the activity of caesium-137 （Bq/kg） in the crustaceous lichens was one order of magnitude higher than that found in surface soil, and was over throe orders of magnitude higher than those found in the familiar biological samples. These results proved that crustaceous lichens may be one of the most sensitive biological monitors about the remote transmission and environmental radiation levels of caesium-137.

Management of infection control and radiological protection in diagnostic radiology examination of COVID-19 cases

Since the COVID-19 outbreak,diagnostic imaging has been providing valuable radiological support for disease diagnosis and prognosis prediction.Radiological staff,especially radiographers working on the front line in the battle against the COVID-19 outbreak.They are in direct contact with the patients,bearing the responsibility and pressure of both the infection prevention and control and the radiation protection.A number of relevant professionals and experts reached a consensus,which clarifies the detailed implementing rules with respective to infection control and protection of the radiation workers,disinfection of diagnostic radiology equipment and workplace,and radiological protection.The aim is to further normalize the clinical procedures of radiological staff,reduce the infection risk,especially the radiation risk to medics and patients.

Regulation Effect of miR-34a Expression on Radiosensitivity of Lung Adenocarcinoma Cells by Targeting Bcl-2 and CDK4/6 Signaling Pathways

Objective: Radiotherapy has been widely used to treat lung cancer. However, non-small lung cancer cells are insensitive to radiation, diminishing their radiotherapy effects. Although the radiosensitivity of the non-small lung cancer cells was reported to be enhanced through regulating miR-34a, the regulation effects of miR-34a expression on radiosensitivity of lung adenocarcinoma cells through target genes CDK4, CDK6, CyclinD1, and Bcl-2/Bax have not been systematically investigated. Methods: In this study, we investigated the effect of miR-34a expression on the Bcl-2, CDK4, and CDK6 pathways in lung adenocarcinoma cells, to provide new insights into the sensitization treatment of lung cancer. We first studied the effect of miR-34a expression on H1299 and A549 cell activity. Then to investigate the mechanisms of radiosensitivity, we focused on apoptosis, cell cycle, and target genes. Results: We find that overexpression of miR-34a in lung adenocarcinoma cells inhibits cell activity, and improves radiosensitivity. Specifically, overexpression of miR-34a suppresses the expression of target genes CDK4, CDK6, CyclinD1, and Bcl-2/Bax, which leads to cell cycle arrest and promotes apoptosis of lung adenocarcinoma cells. Conclusions: Overall, our results demonstrate that the overexpression of miR-34a enhances the radiosensitivity of lung adenocarcinoma cells, indicating that miR-34a is a sensitizer for lung adenocarcinoma radiotherapy.

Effect of 80.55 MeV//u^(12)C^(6+) Ions on Radiosensitivity and Cell Cycle of Human Hepatoma Cell Lines

In this paper, the relationship between radiosensitivity, cell cycle alteration and the change of apoptosis in different human hepatoma cell lines irradiated by heavy ions were studied with the aim of building up the base data for clinical therapy. Exponentially growing hepatoma cell lines were irradiated by 80.55 MeV/u12C6＋ ions at a dose of 0 Gy, 0.5 Gy, 1 Gy, 2 Gy, 4 Gy and 8 Gy. The radiosensitivity was assessed by means of the colony-forming assay. The DNA content, the percentage of each cell-cycle phase and the apoptosis rate were obtained with flow cytometry methods. After the irradiation, the SF2 （survival fraction at 2 gray） of SMMC-7721 cells were evidently lower than that of HepG2 cells. The S phase arrest, G2/M phase arrest delay and the apoptosis in the two hepatoma cell lines varied with the increase of the dose and repair time. The heavy ions could obviously kill the human hepatoma cell lines. Compared to HepG2 cells, SMMC-7721 cells were more radiosensitive to 12C^6＋ ions.

The Role of CHMP4C on Proliferation in the Human Lung Cancer A549 Cells

The human lung cancer has high incidence rate and mortality among the carcinoma. The research on enhancing the efficacy of therapy for lung cancer is significant. A resent research found that as a subunit of ESCRT-III, CHMP4C functioned to retard abscission timing to coordinate midbody resolution and prevent accumulation of DNA damage in the abscission checkpoint through phosphorylated by AuroraB. In the current study, we evaluated the possible mechanism of the effects of CHMP4C inhibition on cell cycle and cell survival in A549 cells. We found that CHMP4C knockdown caused lagging S phase in cell cycle through enhancing the phosphorylation of Rb, raising the expression of cyclin B1-cdc2 and suppressing the activation of cyclin A. Meanwhile, CHMP4Cdeletion depressed cell survival via decreasing cell viability and increasing caspase 3/7 activity. This study may promote new significant reference and advance for the mechanism underlying specific function of CHMP4C as well as further research on enhancing therapy effect on non-small lung cancer.

Inhibition of Radiation-Induced Lung Adenocarcinoma Cell Metastasis by Adenovirus of PIAS3 Overexpression Driven by Radiation-Inducible Promoter (<i>Ad-pig3RRP-PIAS3</i>)

Radiotherapy is one of important approaches for pulmonary adenocarcinoma. However, many studies have shown that radiation can also enhance the ability of tumor cells metastasis, although the lung adenocarcinoma could be killed. The increased metastasis induced by radiation is associated with the activation of STAT3?in lung adenocarcinoma cells. Based on the importance role of?STAT3?in cell proliferation and survival, we can construct an adenovirus vector of?PIAS3 overexpress driven by radiation-induced promoter to inhibit the activation of STAT3 specifically. In this way, when?STAT3 was activated by radiation, the expression of?PIAS3 will be increased at the same time;this lead to the inhibition of invasion and metastasis caused by?STAT3 in lung adenocarcinoma cells. These researches are expected to develop a novel target and method for radiotherapy and molecular therapy of lung adenocarcinoma.