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Objective To explore the uranium concentration in surface water and drinking water in Beijing, China and the relationship between uranium concentration and gross α activity concentration. Methods Water samples were collected from 16 districts in Beijing. Uranium concentration and gross α activity concentration were measured with WGJ-III trace uranium analyzer and LB6008 six-channel α/β counter using the ultraviolet fluorescence and thick source methods. Results The uranium concentrations in surface water and drinking water were 1.131 and 1.572 μg/L, respectively. The gross α activity concentrations in surface water and drinking water were 0.059 and 0.074 Bq/L, respectively. There were no significant differences in uranium concentration and gross α activity concentration between surface water and drinking water (P > 0.05). The uranium concentration was positively correlated with the gross α activity concentration, with a correlation coefficient of 0.700 (P < 0.05). The gross α activity concentration was determined by the uranium concentration with a determination coefficient of 48%. The committed effective dose of 238U in drinking water was between 3.284 × 10−5 and 1.640 × 10−3 mSv, with an average value of 5.400 × 10−4 mSv. Conclusion The uranium concentration and gross α activity in the surface water and drinking water in Beijing fluctuate and remain in the background range. These values are much lower than the recommended limits of 0.03 mg/L and 0.5 Bq/L stipulated in the GB 5749-2021 Standard for Drinking Water Quality. The annual committed effective dose of 238U through drinking water ingestion is very small.
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Objective To understand the effects of 241Am standard material powder with different matrices on the determination of gross alpha activity in water, and to provide a reference for the selection and use of alpha standard sources. Methods The alpha counting efficiency of 241Am standard material powder with different matrices was measured by low-background alpha and beta measuring instrument. The radiochemical recovery rate and whole process efficiency of gross alpha activity in water were determined by spike experiments. Results The alpha counting efficiency of the 241Am standard material powder with four matrices was in the descending order of calcium carbonate, calcium carbonate and silica mixed matrix, calcium sulfate, and silica. The default chemical recovery rate is 1 when gross alpha activity in water is measured by thick source method. The use of 241Am standard material with calcium carbonate as a matrix resulted in about 35% decrease in gross alpha activity, and about 10% deviation was observed using 241Am standard material with silica or calcium carbonate and silica mixed matrices. The whole process efficiency of alpha activity in four spiked water samples with 241Am standard solution and 241Am standard material powder with calcium carbonate, silica, or mixed matrix was 6.34%-7.30%. Conclusion Standard materials with different matrices demonstrate different self-absorption of alpha particles and various influence on the chemical recovery. When purchasing and using standard material powders for alpha activity measurement in laboratories, the composition of the matrix should be clarified as much as possible, and the gross alpha activity in water should be determined by measuring the whole process efficiency if necessary.
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Objective To ensure the accuracy of gamma spectrometer in our laboratory for the analysis of radionuclides in samples and to improve the laboratory personnel’s ability to perform analyses of radionuclides. Methods Our laboratory had continuously participated in the national assessments of gamma spectrometry of radionuclides organized by the Chinese Center for Disease Control and Prevention. The samples were measured by a high-purity germanium gamma spectrometer (GEM-MX7080P4). An analysis was performed on the results of the gamma spectrometry assessments from 2014 to 2021. Results Our laboratory had an overall qualified rate of 100% (8/8) and an overall excellent rate of 39% (3/8) in the gamma spectrometry assessments from 2014 to 2021. The distribution ranges of RD, Z, U, and Urel for 28 measurements involving radionuclides 208Tl, 228Ac, 232Th, 40K, 238U, and 137Cs were −11.82% to 5.97%, −0.59 to 0.30, 0.02 to 0.92, and 4.33% to 10.49%, respectively. Conclusion The methods used in our laboratory for gamma spectrometry of radionuclides are accurate and the testing reports issued by our laboratory are reliable.
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Objective To explore the clinical value of neurography and nerve root sealing in treatment of multilevel lumbar spinal stenosis with lumbar instability using Endo-P/TLIF.Methods A total of 60 patients with multi-segment lumbar spinal stenosis and lumbar instability hospitalized in our hospital were included in this study From January 1,2022 to June 21,2022.All patients underwent nerve root closure angiography before surgery to confirm the responsible segments,and then the responsible segments were treated with Endo-P/TLIF.The patients were followed up for 6 months.The basic information on the age,gender,course of disease,surgical time,intraop-erative bleeding,hospitalization time,and off-bed ambulation time was collected.Then the data on VAS score,ODI score,JOA score,lumbar lordosis angle,intervertebral height,dural cross-sectional area,sacral inclination angle,pelvic projection angle,and pelvic inclination angle before,right after,3 months and 6 months after the operation were calculated.The number of responsible segments indicated by MRI and confirmed by nerve root closure angiography and the number of the single segment,double segments,3 segments,and above finally decompressed were statisti-cally analyzed.Results All patients went through the surgery safely.During the 6-month follow-up,one patient did not return to the hospital for consultation on time,and one patient was out of contact.Finally,the follow-up data of 58 patients were completely collected for statistical analysis.Fifty-five cases were remarkably improved,2 better,and 1 moderately,6 months after the operation,with a total effectiveness rate of 100%.The number of unilateral and bilateral single responsible segments confirmed by nerve root angiography and sealing was significantly larger than by MRI(P<0.05),but the number of unilateral and unilateral double,or multiple responsible segments was signifi-cantly smaller(P<0.05).There were statistically significant differences in terms of postoperative VAS score,ODI score,JOA score,VAS score,ODI score,JOA score,lumbar lordosis angle,intervertebral height,dural cross-sectional area,sacral inclination angle,pelvic inclination angle as compared to the preoperative data(P＜0.05).The pelvic projection angle was insignificantly improved as compared to the preoperative condition(P ? 0.05).Conclusion The accurate diagnosis with selective neurography and nerve root sealing improves the confirmation of responsible nerve segments before operation.Base on the accurate diagnosis,multi-segment lumbar spinal canal stenosis with lumbar instability can be effectively treated with Endo-P/TLIF,the responsible segment decompressed,trauma and bleeding reduced,hospital stay shortened,spinal physiological curvature well recovered,and clinical efficacy improved.Therefore,the method is worthy of extensive application in clinical practice.
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Objective:To investigate the association between serum lipid levels and inflammatory indicators in patients with primary open angle glaucoma (POAG).Methods:A case-control study was conducted.A total of 86 POAG subjects were collected as a POAG group at Joint Shantou International Eye Center of Shantou University and the Chinese University of Hong Kong from January 2016 to March 2022.Meanwhile, 86 with age-related cataract only, matched at age, sex and body mass index were collected as a control group.The intraocular pressure (IOP) and the mean defect of visual field (MD) were measured by Goldmann tonometer and Humphrey field analyzer, respectively.Human peripheral blood samples collected from subjects for serum lipid levels, including total cholesterol, total triglycerides, high density lipoprotein (HDL), and low density lipoprotein (LDL), were analyzed using an automated hematology analyzer and inflammatory markers including C-reactive protein, white blood cells (WBC), neutrophils, lymphocytes, monocytes, were analyzed using an automated biochemical analyzer.Indicators with statistically significant differences between the two groups were selected as independent variables, and multiple logistic regression analysis was used to determine the risk factors for POAG.Correlations between risk factors and ocular parameters (IOP and MD) were assessed using Pearson correlation analysis.This study adhered to the Declaration of Helsinki.The study protocol was approved by the Ethics Committee of Joint Shantou International Eye Center of Shantou University and the Chinese University of Hong Kong (No.EC20210313[2]-P03). Written informed consent was obtained from each patient before any medical examination.Results:The HDL was (1.59±0.42)mmol/L in the POAG group, which was significantly lower than (1.76±0.50)mmol/L in the control group ( t=2.435, P=0.016). The LDL was (3.34±0.66)mmol/L in the POAG group, which was significantly higher than (3.08±0.71)mmol/L in the control group ( t=2.520, P=0.013). The WBC was (6.91±1.60)×10 9/L in the POAG group, which was significantly higher than (6.11±1.29)×10 9/L in the control group ( t=3.619, P<0.001). Multiple logistic regression analysis showed that high serum LDL level ( P=0.039, OR=2.354, 95% CI: 1.105-5.303) and high WBC level ( P=0.044, OR=1.310, 95% CI: 1.007-1.703) were risk factors for POAG.Pearson correlation analysis showed that the serum LDL and WBC levels of POAG patients were moderately positively associated with IOP ( r=0.610, P<0.001; r=0.358, P=0.001). LDL level was moderately negatively associated with MD ( r=-0.496, P<0.001). WBC level was weakly negatively associated with MD ( r=-0.235, P=0.030). Conclusions:The elevated peripheral blood LDL and WBC levels are risk factors for POAG onset.The elevated LDL and WBC levels are positively correlated with IOP and negatively correlated with MD in POAG patients.
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Objective@#To study the output dose of external beam radiotherapy in Beijing and analyze the cause of output dose deviation. Guidance is given on the selection of measurement methods, calculation formulas and parameters.@*Methods@#During 2020, the output doses of medical electron accelerators, tomotherapy, cyberknife, and γ-knife were meas- ured based on the water absorbed dose calibration factor combined with the requirements in the IAEA TRS398 and TRS483 reports, and low-energy X-rays were measured based on the air kerma calibration factor combined with the requirements in the AAPM protocal. The output dose was measured and compared with the preset irradiation value.@*Results @#A total of 59 external beam radiation therapy equipments’s output dose were investigated.2 of the 49 accelerators’s absolute value of relative deviation between the system indication value and the measurement exceeded 3%; the deviation of other external beam radiotherapy equipments was less than 3%.@*Conclusion @#A unified method and multi-party quality control can ensure the accuracy of the output dose. In the routine operation of the equipment, the hospital should strictly implement periodic inspections to ensure accurate and reliable radiotherapy.
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BACKGROUND:Preliminary data showed that the application of human platelet lysate to human umbilical cord mesenchymal stem cell culture can better maintain the characteristics of stem cells than the application of serum-free medium. However, the serum-free medium can better improve the proliferation of mesenchymal stem cells in vitro than the human platelet lysate.OBJECTIVE:To screen out a better mesenchymal stem cell cultivation system that can greatly maintain the characteristics and proliferation rate of human umbilical cord mesenchymal stem cells.METHODS:Six human umbilical cord specimens were inoculated in six culture systems, and the primary culture of umbilical cord mesenchymal stem cell was performed. These six culture systems were respectively MesenCult serum-free medium with 2% human platelet lysate (group A), StemPro serum-free medium with 2% human platelet lysate (group B), MesenCult serum-free medium (group C), StemPro serum-free medium (group D), low glucose-DMEM with 10% fetal bovine serum (group E), low glucose-DMEM with 10% human platelet lysate (group F). The cells were subcultured at 14 days after inoculation to compare the effects of different culture systems on the morphology, surface markers, differentiation and proliferation of human umbilical cord mesenchymal stem cells.RESULTS AND CONCLUSION:(1) The morphology of passage 3 cells in group D was elongated and uneven in size. The morphology of passage 3 cells was flattened in groups E and F, but the cells in the other groups were spindle-shaped and uniform. There were no significant changes in morphology and size between passage 3 and 5 cells in A and B. In group C, the morphology of passage 5 cells was more flattened and uneven in size compared with passage 3 cells. In group D, the morphology of passage 5 cells was more elongated than that of passage 3 cell. In group E, the morphology of passage 5 cells was more flattened than that of passage 3 cells. There was no significant difference in morphology between passage 3 and 5 cells in group F. (2) The expression rate of cell surface markers had no significant difference at different passages in each group. (3) The adipoinduction and osteoinduction rates were relatively higher in groups A and B compared with groups E and F, and lowest in groups C and D. (4) The cell proliferation rate for each passages in group A was significantly higher than that in group C. The cell proliferation rate for each passage in group B was significantly higher than that in group D. The cell proliferation rate for each passage in groups E and F was significantly lower than that in groups A and B. To conclude, these results suggest that the combination of serum-free medium with human platelet lysate could better maintain the characteristics and the proliferation efficiency of mesenchymal stem cells.
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Objective To explore the effect of radon released from water on the indoor radon activity concentration in groundwater supplies.Methods Two groundwater supplies in a city were chosen.Radon concentrations in three kinds of water samples were determined by using a continuous radon monitor with air-water exchanger,including source water,finished water and tap water.The solid track detector was used to analyze the indoor radon concentration in water supplies.Results The concentrations of radon in source water,finished water and tap water were (7.59 ± 1.36),(3.56 ±0.86),(3.68 ±0.81)Bq/L and (12.19 ±0.57),(7.87 ± 1.12),(9.50 t 1.12) Bq/L,respectively.The concentration of radon was the highest in source water and at less varying level in finished water and tap water.Aeration and filtration tank process significantly decreased radon activity in water.Radon concentrations in aeration and filtration rooms were 4 218 Bq/m3 and 1 937 Bq/m3,respectively,which exceeded the limit in work place (1 000 Bq/m3).Conclusions Aeration and filtration workplaces for groundwater supplies were found to contain elevated radon concentrations in air,which was released from groundwater.Radon issues in groundwater supplies in China should be paid more attention.