Objective As an important monitoring target for gaseous effluents from nuclear facilities, the radioactive inert gas ⁸⁵Kr requires accurate measurement, which is crucial for nuclear safety and radiation protection. This study organized an inter-laboratory comparison activity for ⁸⁵Kr gamma-ray spectrometry measurements, with the aims of identifying potential problems in ⁸⁵Kr measurement and improving detection capabilities and proficiency. Methods Four laboratories participated in this comparison. Each laboratory employed gamma-ray spectrometry to measure the comparison samples, and the results were evaluated using the E_n value. Results The measurement results from all participating institutions were acceptable, with the maximum E_n value being 0.73. The results demonstrate that despite the low gamma-ray branching ratio of ⁸⁵Kr and its susceptibility to interference from the 511 keV positron annihilation peak, gamma-ray spectrometry can achieve reliable activity measurements of ⁸⁵Kr. Conclusion The comparison for ⁸⁵Kr gamma-ray spectrometry tested the capabilities of the participating laboratories in ⁸⁵Kr measurement. It promoted technical exchange and experience sharing among laboratories, laying a foundation for future comparisons involving more complex radioactive inert gases.

To characterize the genomes of different emm-type group A Streptococcus (GAS), their virulence genes and drug resistance profiles in Tianjin City from 2011 to 2024. After PCR, a total of 42 strains with different years and emm types were selected for whole genome sequencing and multi-locus sequence typing (MLST), and the core genomes were used to generate a phylogenetic tree, after which the virulence genes and resistance genes were identified and analyzed, followed by the drug susceptibility test. In this study, the GAS strains were dominated by emm1 (50.0%) and emm12 (40.4%), and the MLST phenotypes were categorized into six types: ST36 (40.4%), ST1274 (26.1%), ST28 (23.8%), ST921 (4.7%), ST46 (2.3%), and ST403 (2.3%). There was a high consistency between their emm-types and ST types. A total of 68 virulence genes were detected in the genomes of 42 GAS strains, involving functional genes encoding exotoxin, bacterial adhesion, extracellular enzymes, etc. The virulence genes they carried were significantly different between emm1-type and emm12-type strains, such as speA. At the same time, the carrying rates of some virulence genes in the same emm-type strains changed with time, such as hyl. The resistance genes were basically the same among different emm-type strains except for the vanSE gene detected in all emm12 strains. The results of drug sensitivity showed that the GAS strains isolated in Tianjin City from 2011 to 2024 were sensitive to penicillin, cefazolin, chloramphenicol, vancomycin, and levofloxacin, while the resistance rates to erythromycin, azithromycin, clarithromycin, and clindamycin ranged from 88.5% to 100.0%, and there was a certain degree of consistency between the resistance phenotypes and the detected resistance genes. Overall, the main emm types and evolutionary features of GAS in Tianjin City from 2011 to 2024 were consistent with the dominant types in China, and the carrying rate of virulence genes and drug resistance genes differed significantly among different emm-type strains, and there were continuous evolution and variation in the prevalence of virulence genes in GAS.

Objective:To investigate the relationship between artificial radionuclide 137Cs and stable cesium (Cs) in wild edible fungi and seek potential correlations. Methods:A total of 30 samples, including the caps (with gills) and stipes of wild edible fungi, were collected from the northeastern region of China. The measurement and analysis of 137Cs were conducted following recommended procedures in GB/T 16145-2022, and stable Cs was determined using inductively coupled plasma mass spectrometry (ICP-MS). Then, the correlation analysis of data on 137Cs and stable Cs was performed using SPSS 11.5 software, and scatter plots were prepared using the Origin 21.0 software. Results:The fungi caps exhibited a specific activity of 137Cs ranging from 0.52 to 55.9 Bq/kg (dry weight) and a stable Cs content from 0.069 mg/kg to 16.2 mg/kg (dry weight). The stipes showed a specific activity of 137Cs ranging from 0.53 Bq/kg to 101 Bq/kg (dry weight) and a stable Cs content from 0.075 to 11.5 mg/kg (dry weight). These data revealed a significant correlation between the specific activity of 137Cs and the stable cesium content in all samples including caps and stipes, with correlation coefficients r of 0.956, 0.912, and 0.931, respectively, and all significant levels P < 0.01. The ratios of the specific activity of 137Cs to stable Cs content varied from 2.09 Bq/kg to 20.1 Bq/kg (dry weight), with an average of 10.7 Bq/kg (dry weight). Conclusions:Wild edible fungi fail to distinguish between 137Cs and stable cesium when absorbing Cs elements from their growing substrates. Furthermore, there is a strong correlation between the specific activity of 137Cs and stable Cs content. In the case of exogenous 137Cs contamination, the ratio of the specific activity of 137Cs and stable Cs content will significantly change. Therefore, an increase in the ratio can be used as a reference for identifying 137Cs contamination events.

Objective:To understand the activity concentrations of varying chemical forms of 131I in nuclear medicine workplaces and assess the internal irradiation doses of 131I to workers. Methods:A high-volume air sampler was used for air sampling of 131I. Glass fiber filters, activated carbon filters, and iodine cartridges, which were connected in series, were employed to collect aerosol iodine, gaseous inorganic iodine, and gaseous organic iodine, respectively. A method for analyzing the activity of 131I unevenly distributed in the iodine cartridge was developed, and an HPGe γ spectrometer was used to determine the activity of 131I in samples collected from the nuclear medicine workplaces of 15 hospitals. Results:The concentrations of aerosol iodine, inorganic iodine, and organic iodine in 15 hospitals were determined at 0.19-206.67, 0.27-138.45, and 2.35-3 821.11 Bq/m 3, respectively, with arithmetic means of 22.04, 12.79 and 365.08 Bq/m 3, respectively. The maximum annual committed effective doses of varied forms of 131I inhaled by workers were determined at 0.19, 0.19, and 3.81 mSv, respectively, with a maximum total committed effective dose of 4.13 mSv. Conclusions:Gaseous organic iodine is identified as the primary form of 131I in the air within nuclear medicine workplaces. Therefore, it is necessary to highlight the monitoring and protection of gaseous organic iodine.

To characterize the genomes of different emm-type group A Streptococcus (GAS), their virulence genes and drug resistance profiles in Tianjin City from 2011 to 2024. After PCR, a total of 42 strains with different years and emm types were selected for whole genome sequencing and multi-locus sequence typing (MLST), and the core genomes were used to generate a phylogenetic tree, after which the virulence genes and resistance genes were identified and analyzed, followed by the drug susceptibility test. In this study, the GAS strains were dominated by emm1 (50.0%) and emm12 (40.4%), and the MLST phenotypes were categorized into six types: ST36 (40.4%), ST1274 (26.1%), ST28 (23.8%), ST921 (4.7%), ST46 (2.3%), and ST403 (2.3%). There was a high consistency between their emm-types and ST types. A total of 68 virulence genes were detected in the genomes of 42 GAS strains, involving functional genes encoding exotoxin, bacterial adhesion, extracellular enzymes, etc. The virulence genes they carried were significantly different between emm1-type and emm12-type strains, such as speA. At the same time, the carrying rates of some virulence genes in the same emm-type strains changed with time, such as hyl. The resistance genes were basically the same among different emm-type strains except for the vanSE gene detected in all emm12 strains. The results of drug sensitivity showed that the GAS strains isolated in Tianjin City from 2011 to 2024 were sensitive to penicillin, cefazolin, chloramphenicol, vancomycin, and levofloxacin, while the resistance rates to erythromycin, azithromycin, clarithromycin, and clindamycin ranged from 88.5% to 100.0%, and there was a certain degree of consistency between the resistance phenotypes and the detected resistance genes. Overall, the main emm types and evolutionary features of GAS in Tianjin City from 2011 to 2024 were consistent with the dominant types in China, and the carrying rate of virulence genes and drug resistance genes differed significantly among different emm-type strains, and there were continuous evolution and variation in the prevalence of virulence genes in GAS.

Objective:To investigate the relationship between artificial radionuclide 137Cs and stable cesium (Cs) in wild edible fungi and seek potential correlations. Methods:A total of 30 samples, including the caps (with gills) and stipes of wild edible fungi, were collected from the northeastern region of China. The measurement and analysis of 137Cs were conducted following recommended procedures in GB/T 16145-2022, and stable Cs was determined using inductively coupled plasma mass spectrometry (ICP-MS). Then, the correlation analysis of data on 137Cs and stable Cs was performed using SPSS 11.5 software, and scatter plots were prepared using the Origin 21.0 software. Results:The fungi caps exhibited a specific activity of 137Cs ranging from 0.52 to 55.9 Bq/kg (dry weight) and a stable Cs content from 0.069 mg/kg to 16.2 mg/kg (dry weight). The stipes showed a specific activity of 137Cs ranging from 0.53 Bq/kg to 101 Bq/kg (dry weight) and a stable Cs content from 0.075 to 11.5 mg/kg (dry weight). These data revealed a significant correlation between the specific activity of 137Cs and the stable cesium content in all samples including caps and stipes, with correlation coefficients r of 0.956, 0.912, and 0.931, respectively, and all significant levels P < 0.01. The ratios of the specific activity of 137Cs to stable Cs content varied from 2.09 Bq/kg to 20.1 Bq/kg (dry weight), with an average of 10.7 Bq/kg (dry weight). Conclusions:Wild edible fungi fail to distinguish between 137Cs and stable cesium when absorbing Cs elements from their growing substrates. Furthermore, there is a strong correlation between the specific activity of 137Cs and stable Cs content. In the case of exogenous 137Cs contamination, the ratio of the specific activity of 137Cs and stable Cs content will significantly change. Therefore, an increase in the ratio can be used as a reference for identifying 137Cs contamination events.

Objective:To understand the activity concentrations of varying chemical forms of 131I in nuclear medicine workplaces and assess the internal irradiation doses of 131I to workers. Methods:A high-volume air sampler was used for air sampling of 131I. Glass fiber filters, activated carbon filters, and iodine cartridges, which were connected in series, were employed to collect aerosol iodine, gaseous inorganic iodine, and gaseous organic iodine, respectively. A method for analyzing the activity of 131I unevenly distributed in the iodine cartridge was developed, and an HPGe γ spectrometer was used to determine the activity of 131I in samples collected from the nuclear medicine workplaces of 15 hospitals. Results:The concentrations of aerosol iodine, inorganic iodine, and organic iodine in 15 hospitals were determined at 0.19-206.67, 0.27-138.45, and 2.35-3 821.11 Bq/m 3, respectively, with arithmetic means of 22.04, 12.79 and 365.08 Bq/m 3, respectively. The maximum annual committed effective doses of varied forms of 131I inhaled by workers were determined at 0.19, 0.19, and 3.81 mSv, respectively, with a maximum total committed effective dose of 4.13 mSv. Conclusions:Gaseous organic iodine is identified as the primary form of 131I in the air within nuclear medicine workplaces. Therefore, it is necessary to highlight the monitoring and protection of gaseous organic iodine.

Objective:To recommend reference composition for sourceless efficiency calibration of food gamma spectrometry by analyzing the composition of common foods based on a combination of sourceless efficiency calibration and active validation.Methods:Thirty common types of food samples in countrywide monitoring of radioactively contaminated foods were analyzed to statistically determine the reference composition of grains and vegetables. Combined with the parameters provided for white quinoa standard source, LabSOCS was applied to carry out the simulation of sourceless efficiency for its different compositions, and to calculate its measured activity, and analyzing its relative deviation to the those given in the certificate.Results:The analytical result of these 30 types of food samples showed that the five elements C, H, O, N and S accounted for 77.0%-93.7% of the food composition, being the main component of these samples. By applying white quinoa′s components and grain-based reference components to the simulation of the sourceless efficiency of white quinoa standard sources, the relative deviations of activity calculations to their certificated activities were in the range of 0.37%-5.86% and 0.38%-5.87% in absolute value, respectively.Conclusions:The white quinoa′s composition and the grain reference composition were applied to the sourceless efficiency simulation of the white quinoa standard source, and the relative deviation of the calculated measured activity to the activity of the standard source certificate was basically identical, so that if the gamma spectrometry-based sourceless efficiency simulation is used to measure the unknown composition of the food samples and it is inconvenient to carry out the analysis of the food samples′ compositions, especially in the case of emergency, it can be referred to the use of the reference compositions obtained in the present study.

Objective To further extend the application of coincidence summing correction factor transfer experiments through the analysis of relevant measurements. Methods The passive efficiency was simulated using BE5030 high-purity germanium (HPGe) γ-energy spectrometer equipped with LabSOCS, and the total efficiency was simulated using LabSOCS in GENIE 2000 spectrum analysis software, which was used for calculating the coincidence summing correction factor. The coincidence summing correction factor transfer experiments were performed using the measurements with the point source containing ¹³⁴Cs, ⁶⁰Co, and ¹³⁷Cs as well as the body source to obtain the coincidence summing correction factors of other HPGe γ-energy spectrometers. Results The coincidence summing correction factors for ¹³⁴Cs and ⁶⁰Co were obtained using the BE5030 γ-energy spectrum. In verification by certificate activity, the absolute value of the maximum deviation was within 3.53%. Using coincidence summing correction factor transfer experiments, these factors were transferred to other high-purity germanium γ spectrometers. In verification by certificate activity, the absolute value of the maximum deviation was within 5.86%. Conclusion The coincidence summing correction factors calculated using simulated total efficiency by calling LabSOCS in the GENIE 2000 spectrum analysis software are effective in correction, and can be used as correction factors in standard laboratories. Through coincidence summing correction factor transfer experiments, the coincidence summing correction of other high-purity germanium γ-energy spectrometers can be achieved, which broadens the application of coincidence summing correction method.

BACKGROUND:Numerous scholars have previously researched certain greater tuberosity fractures and the procedures used to treat them.Few researchers,however,have studied the comminuted split fracture of the greater tuberosity of the humerus(Liu-Gang type IV)with rotator cuff tear in great detail. OBJECTIVE:To compare the clinical therapeutic effect of open repair position modified calcaneal plate combined with suture anchors and proximal humeral internal locking system(PHILOS)plate in the treatment of comminuted fracture of split-type greater tuberosity of humerus combined with rotator cuff tears(Liu-Gang type IV). METHODS:Case data of 30 patients with comminuted fracture of split-type greater tuberosity of humerus combined with rotator cuff tears(Liu-Gang type IV)from May 2012 to May 2022 were retrospectively analyzed.They were divided into the modified calcaneal plate combined with suture anchor group(group A)and the PHILOS with#2 Johnson group(group B),with 15 cases in each group.Intraoperative blood loss,surgical time,and incision length of all patients were recorded.Pain visual analog scale score,Constant-Murley score,as well as shoulder joint abduction,forward flexion,external rotation,and dorsal expansion activities during the last follow-up(>1 year)were evaluated. RESULTS AND CONCLUSION:(1)The surgical incision length and operation time were shorter,and blood loss was less in group A than those in group B(P<0.05).(2)No significant difference in visual analog scale score and Constant-Murley score was detected between the two groups(P>0.05).(3)During the last follow-up,forward flexion in group A was better than that in group B(P<0.05).No significant difference in abduction,external rotation,and dorsal expansion was determined between group A and group B(P>0.05).(4)In terms of complications,there was 1 case of shoulder joint pain and discomfort in group A(7%),2 cases of subacromial impingement syndrome,2 cases of upward movement of nodules,and 2 cases of shoulder joint pain(40%)in group B.There were significant differences in complication rates between the two groups(P=0.031).(5)In summary,the modified calcaneal plate combined with suture anchors in the treatment of comminuted fracture of split-type greater tuberosity of humerus combined with rotator cuff tears(Liu-Gang type IV)could better restore the forward flexion function of the shoulder joint and has a small incision,less blood loss,shorter operation time and fewer complications.