The extraction method with organic solvent extraction to detect nitric oxide was improved, and the production of nitric oxide in mice myocardium in vitro was detected with this method. Using organic solvent (DETC)2-Fe2 + -NO complex was extracted from water phase into ester phase, and nitric oxide in sample of large volume can be detected by ESR at room temperature. The extracting ability of several organic solvents such as ethyl acetate, butyl acetate, glycerol triacetate, iso-amy lacetate, and n-butanol, was compared, and it was found that ethyl acetate was a good kind of organic solvent. There was a good linear relationship between the concentration of nitric oxide and ESR intensity within concentration of 20μmol/L, and the detected limit was improved to below 200 nmol/L; (DETC)2-Fe2+ -NO complex is easy to decompose in light but it is very stable in dark at 0～4℃ which, there is only a little change after ten days.

AimTo investigate the influence of tetramethylpyrazine(ligustrazine, Lig) on oxygen consumption and superoxide during the respiratory burst of human neutrophils. MethodsIt was observed by using ESR spin trapping, spin probe oxymetry and luminol-dependent chemiluminesence(CL) . Results Lig had no influence on oxygen consumption during the respiratory burst of neutrophils(P＞0.05), but had remarkable inhibition on CL response generated by neutrophils(P＜0.01), and had scavenging effect on O2 and OH ·generated by neutrophils, which were demonstrated in xanthine/ xanthine oxidase system and Fentons reaction(P＜0.01) . ConclusionLig has no inhibiting effect on oxygen metabolic function of neutrophils,but protects tissue from injury caused by activated neutrophils through scavenging oxygen radicals.

Objective To study the variation in net count rates of natural radionuclides in background of gamma-ray spectrometer,so as to provide a scientific basis for reducing the effect of background fluctuations on sample measurement.Methods The unscheduled background spectrum obtained using two high-purity gamma-ray spectrometers during 2013-2017 were collected,and then the net count rates of 210pb,234Th,212Pb,214pb,208Tl,214Bi,228Ac and 40K were calculated and analyzed by aid of statistical method.Results There was a significant difference in the net count rates of 210Pb,234Th,212Pb,214Pb,208Tl,214Bi,228Ac and 40K in the background spectrum of gamma-ray spectrometer,and the net count rates of 214Pb,214Bi and 40K was significantly higher than those of 210Pb,234Th,212pb,208Tl and 228Ac.There were no significant differences in the net count rates of these eight natural radionuclides from 2013 to 2017,respectively (P ＞ O.05).However,the coefficients of variation in the net count rates for 214pb and 214Bi were both greater than 50％.Conclusions When the activity concentration of natural radionuclides is determined in a sample by gamma-ray spectrometer,it is critical to subtract the background spectrum obtained recently to ensure the accuracy of the measurement,especially for the low activity concentration of natural radionuclide to be measured.

Objective:To improve the radionuclide measurement technology by γ-spectrometry throuth a review of the intercomparisons between China and Japan results over the past 20 years.Methods:Before the beginning of each intercomparison, one of participating laboratories was agreed to be responsible for preparing the samples for the intercomparison. By intercomparison of the measurement results arnong the laboratories some potential problems during the sample pre-trement or analysis were found and solved.Results:The intercomparisons had been carried out for 11 times over the past 20 years. Totally 290 measured and analyzed results had been obtained from 20 samples of six categories. The proportion 95.5% of measurement results were in agreement with each other within the deviation range.Conclusions:The measuring and analytical capability of the laboratories involved were tested. The intercomparisons also provide long-term quality assurance measures for the radionuclide measurement and analysis in each laboratory.

Objective:To compare the clinical effectiveness between arthroscopic hollow screws combined with a suture anchor, hollow screws and proximal humerus internal locking system (PHILOS) in the treatment of split-type fractures of humeral greater tuberosity.Methods:A retrospective study was conducted to analyze the 54 patients with split-type fracture of humeral greater tuberosity who had been admitted to Department of Joint Surgery, Hospital of Traditional Chinese Medicine, Affiliated to Southwest Medical University from May 2015 to August 2020. There were 17 males and 37 females with an age of (58.4±12.1) years. According to different treatment methods, they were divided into 3 groups. Group A of 18 cases was treated with arthroscopic hollow screws combined with a suture anchor, group B of 18 cases with hollow screws, and group C of 18 cases with PHILOS. The length of surgical incision, and range of shoulder motion, visual analogue scale (VAS), and American Shoulder and Elbow Surgeons (ASES) score at the last follow-up were recorded and compared between the 3 groups.Results:There was no statistically significant difference in the preoperative general information between the 3 groups, indicating the 3 groups were comparable ( P>0.05). The surgical incision in group A [(0.7±0.1) cm] was the shortest, followed by (5.0±1.4) cm in group B, and (12.8±2.1) cm in group C, showing statistically significant differences in pairwise comparison ( P<0.05). In the 3 groups at the last follow-up, respectively, the shoulder forward flexion was 159.7°±13.4°, 154.9°±16.2°, and 160.5°±12.9°, and the shoulder abduction 149.6°±11.3°, 142.4°±12.0°, and 145.1°±10.4°, showing no statistically significant difference among the 3 groups ( P>0.05); the external rotation was 41.1°±8.1°, 38.1°±7.8° and 43.7°±6.2°, showing a statistically significant difference between groups B and C ( P<0.05); the dorsal extension was T 12 (L 5 to T 6), T 12 (L 5 to T 7), and T 12 (L 3 to T 6), showing no statistically significant difference among the 3 groups ( P>0.05). There was no statistically significant difference among the 3 groups in the VAS score or ASES score at the last follow-up ( P>0.05). Respectively, there were 2, 6, and 4 patients in groups A, B and C who developed complications, showing statistically significant differences between the 3 groups ( P<0.05). Conclusions:In the treatment of split fractures of humeral greater tuberosity, arthroscopic hollow screws combined with a suture anchor, hollow screws and PHILOS can all relieve pain and restore joint function of the shoulder. However, arthroscopic hollow screws combined with a suture anchor are the most recommendable due to their advantages in minimally invasiveness and reduction in complications.

Objective:To measure the influencing factors associated with the analysis of 226Ra gamma spectra in order to obtain more acurate and precise measuring result on a basis of further optimizing the gamma spectrometry method for 226Ra activity. Methods:A laboratory-based HPGe gamma spectrometer was used to carry out the studies on tracking measurement of sample sealing time, measurement of background fluctuation with lead shielding, analytical method, and selection of characteristic gamma ray energy peak of its daughter nuclides in 226Ra measurement. Results:After the sample was sealed for 12 d, the decay products of 226Ra- 222Rn basically reached equilibrium. The day and night fluctuations of 222Rn in the shielded lead room were obvious but had no obvious regularity. The way of filling nitrogen into the shielded lead room could reduce or avoid the influence of background fluctuations. For 31 soil samples measured after 23 days of sealing, the result of using the efficiency curve method showed that the 226Ra result calculated from the 351.9 keV energy peak were generally higher than the 609.3 keV energy peak, and the higher ratio ranged from 8.0% to 20.7%. The result of relative comparison method showed that the deviation ratio of the two peaks ranged from -4.1 % to 10.3 %. Conclusions:It is recommended to consider the uncertainty attributed from decay equilibrium about 4 % of measured at 12 d after the sample is sealed. When filling nitrogen through the shielded lead chamber to avoid background fluctuations, attention must be paid to the matching relationship between the volume of the lead chamber and the nitrogen filling flow. When the efficiency curve method is used to analyze the activity of 226Ra, the 214Bi ( 609.3 keV ) energy peak has the effect of cascade coincidence addition, so 214Bi(609.3 keV) energy peak should be avoided. When the relative comparison method is used to analyze the activity of 226Ra, both two energy peaks of 214Pb ( 351.9 keV ) and 214Bi ( 609.3 keV ) can be used.

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 The effect of sieved particle size and equilibration time of soil samples on the measurement of radionuclides was studied to improve the accuracy of the specific activity of radionuclides in soil samples measured by gamma spectrometer. Methods The collected soil samples were dried and divided into four parts. After sieved with width of the mesh 2.0 mm, 1.0 mm, 0.5 mm and 0.25 mm respectively, they were filled into sample containers and sealed. The activity concentrations of ²²⁶Ra, ²¹⁰Pb, ²²⁸Ra, ⁴⁰K and ¹³⁷Cs in different sieved soil samples were then measured at the sealed interval of 0, 4, 8, 12, 16, 21, 25 and 29 days by HPGe gamma-ray spectrometry respectively. Results The coefficients of variation ofthe specific activities of ²²⁶Ra, ²¹⁰Pb, and ²²⁸Ra in soil samples measured at different equilibration intervals range from 0.9% to 4.3%. The coefficients of variation of the specific activities of ²²⁶Ra, ²¹⁰Pb, ²²⁸Ra, ⁴⁰K and ¹³⁷Cs in soil samples with different sieved particle sizes range from 3.7% to 14.1%. Conclusion When the specific activities of radionuclides are determined by gamma-ray spectrometer, the effect of the sieved particle size on the measurement result must be considered, and its impact is higher than the equilibration time. This study is very useful for improving the accuracy of the determination of radionuclides in soil sample using gamma-ray spectrometer.

Objective To correct the counting loss of ³⁷Ar below the activity threshold during the measurement of the absolute activity of the inert radioactive gas ³⁷Ar using the proportional counter filled with gas. Methods Monte Carlo simulation with Geant4 was performed to establish a proportional counter model and output the energy deposition spectrum of ³⁷Ar, which were used to simulate and analyze the causes and correction of counting loss. Results The photon detection efficiency was only 38.7% at 60 kPa. The counting loss was mainly caused by the wall effect produced by the photons, which could be reduced by increasing the gas pressure and corrected by extrapolation. The influence of wall effect at 100 kPa was 4.4%, and the deviation between simulation and experiment was < 0.6%. Conclusion A factor could be calculated by Geant4 simulation for the correction of counting loss, thus achieving the accurate measurement of ³⁷Ar activity by proportional counter.

Objective To apply InSpector 1000 portable γ spectrometer and its corresponding supporting software to the monitoring of thyroid ¹³¹I activity of radiation workers, and to estimate the internal radiation dose of medical staff in nuclear medicine department. Methods The spectrometer was calibrated and taken to participate in the 2018 thyroid radioactive iodine intercomparison program initiated by Lawrence Livermore National Laboratory in the United States to ensure the accuracy of the measurement; the spectrometer was used to measure ¹³¹I activity ofthe radiation workers of the nuclear medicine departments of two grade-A tertiary hospitals in Beijing and Jinan to verify the feasibility of the method. Results The InSpector 1000 portable γ spectrometer was qualified for international intercomparison. Measurement results from the grade-A tertiary hospital in Beijing showed that the thyroid ¹³¹I activity of each of 10 radiation workers was below the detection limit (33.30 Bq). Measurement results from the grade-A tertiary hospital in Jinan showed that the thyroid ¹³¹I activities of the 4 radiation workers were 64.05 Bq, 160.77 Bq, 416.67 Bq, below the detection limit (35.18 Bq) respectively, and of 3 of the 4 subjects ¹³¹I was detected in the thyroid, and their corresponding thyroid accumulative organ doses were 0.70 μSv, 1.77 μSv, and 4.58 μSv, respectively. Conclusion InSpector 1000 portable γ spectrometer has a strong feasibility for thyroid ¹³¹I monitoring of radiation workers in nuclear medicine. The spectrometer has a good application prospect in the field of radiation monitoring, and can play an important role in the field of radiation protection and nuclear emergency detection.