Objective To evaluate the environmental radioactive safety level in China, monitor the radioactivity of strontium-90 (⁹⁰Sr) in seafood from selected marine regions of China, and optimize the di-(2-ethylhexyl)phosphoric acid (HDEHP) extraction chromatography method for determining Sr-90 in seafood. Methods In 2023, seafoods of fish, shrimp, shellfish, and seaweed were collected from the Shandong Province (Bohai Sea and Yellow Sea) and Hainan Province (South China Sea). The levels of Sr in the samples were determined by inductively coupled plasma atomic emission spectrometer (ICP-AES). The ⁹⁰Sr separation were performed using HDEHP extraction chromatography, while the recovery of ⁹⁰Sr were determined by the gravitmetry with the assistant of ICP-AES. Results The content of strontium in seafoods varies greatly, and excessive strontium and calcium in seafood may lead to overestimated recovery due to insufficient leaching during chromatographic separation by HDEHP extraction. Therefore, the yttrium content in the eluent should be analyzed by ICP . The radioactivity of ⁹⁰Sr in seafood from the sea areas in Shandong Province was 0.22-1.85 Bq/kg (dry weight), and that of seafood from Hainan Province was 0.19-1.82 Bq/kg (dry weight). Conclusion For the analysis of shirmp and seaweed samples, the recovery rate of ⁹⁰Sr should be analyzed using both gravimetry and ICP-AES. There is no significant linear correlation between total Sr and ⁹⁰Sr in seafood. There is no significant difference in ⁹⁰Sr radioactivity between the seafood samples collected from Shandong and Hainan. The ⁹⁰Sr radioactivity levels of all 28 samples are below the limit specified in the Limited concentrations of radioactive materials in foods (GB 14882—1994) and are within the range of environmental background fluctuations.

Objective To organize a nationwide interlaboratory comparison for measurement of gross α and gross β radioactivity in water, and improve the laboratory analysis of gross α and gross β radioactivity in water. Methods A unified comparison protocol was developed by the organizers. The groundwater with high natural radioactivity was used as water sample and distributed randomly to the participating laboratories. The participating laboratories used routine analytical methods to measure the samples and provided information such as analytical results, original records, and test reports. The results were evaluated using z-score. Results A total of 76 laboratories participated in the comparison, all employing the evaporation concentration-α/β counting method. Among them, 69 laboratories achieved |z| ≤ 2 for both gross α and gross β radioactivity measurements, and 32 laboratories achieved |z| ≤ 0.50 for both gross α and gross β radioactivity measurements. There were 69 laboratories with qualified results and 30 laboratories with excellent results, yielding a qualified rate of 90.8% and an excellent rate of 39.5%. Seven laboratories showed unqualified results and the unqualified rate was 9.2%. Conclusion Most laboratories have the ability to analyze gross α and gross β radioactivity in water. The main reasons for the deviation in comparison results are calibration efficiency, errors in the total residue mass caused by improper water sample processing operations. By analyzing the main technical problems existed in unqualified laboratories, their ability for measurement of gross α and gross β radioactivity in water has been improved.

Radiation-induced adverse reactions in organs at risk(OAR) is recognized as a significant factor limiting doses to clinical target volumes(CTV). Magnetic ferrite nanoparticles, distinguished by their unique physicochemical properties such as ease of modification and high biocompatibility, have been extensively investigated in the biomedical field. This article reviews the latest advances in research on the application of magnetic ferrite nanoparticles in radiotherapy, focusing on their magnetothermal effect, dose enhancement effect, promotion of ferroptosis, regulation of the cell cycle, and improvement in image-guided quality. Furthermore, this article provides an outlook for future research.

Objective:To develop a method for determining 14C in seafood using a tube combustion furnace (or oxygen bomb combustion devices) coupled with liquid scintillation counting (LSC), in order to accurately determine 14C in seafood. Methods:Four categories of seafood samples (i.e., fish, crustaceans, mollusks, and algae) were collected. They were then subjected to high-temperature oxidation using a tube combustion furnace or oxygen bomb combustion devices to isolate CO 2, followed by an analysis of the radioactivity concentration of 14C using LSC. The combustion conditions were optimized by investigating the heating nodes and rates in the oxidation combustion furnace, and the CO 2 collection conditions were optimized by placing a NaOH absorption solution in the oxygen bomb combustion devices. Additionally, the optimal measurement conditions were determined by comparing the effects of varying scintillation cocktails and the dark adaptation time of two preparation methods, i. e., the adsorption and suspension method. Results:When a tubular combustion furnace was used for oxidation and combustion, the optimal heating rate of the sample pyrolysis temperature zone was determined at 1.5℃/min. In this case, the combustion efficiency of various seafood could reach over 95%. When the oxygen bomb combustion devices were employed, placing NaOH solutions both inside and at the exhaust end increased absorption efficiency by 10% compared to the traditional practice of placing a NaOH solution only at the exhaust end. Samples prepared using the absorption method should be kept in the dark for at least 10 h before measurement using LSC, while samples prepared with the suspension methods should be kept for at least 20 h. The results obtained using two preprocessing devices and two sample preparation method were consistent, with a detection limit of 9.10 Bq/kg (dry samples). Compared to the suspension method (The relative standard deviation of the results obtained by two preprocessing devices were 9.00% and 8.27%), the absorption method (the corresponding relative standard deviation were 3.61% and 3.29%) exhibited higher precision in repeated measurements.Conclusions:The aforementioned pretreatment devices and sample preparation method are suitable for determining 14C in seafood.

Radiation-induced adverse reactions in organs at risk(OAR) is recognized as a significant factor limiting doses to clinical target volumes(CTV). Magnetic ferrite nanoparticles, distinguished by their unique physicochemical properties such as ease of modification and high biocompatibility, have been extensively investigated in the biomedical field. This article reviews the latest advances in research on the application of magnetic ferrite nanoparticles in radiotherapy, focusing on their magnetothermal effect, dose enhancement effect, promotion of ferroptosis, regulation of the cell cycle, and improvement in image-guided quality. Furthermore, this article provides an outlook for future research.

Objective:To develop a method for determining 14C in seafood using a tube combustion furnace (or oxygen bomb combustion devices) coupled with liquid scintillation counting (LSC), in order to accurately determine 14C in seafood. Methods:Four categories of seafood samples (i.e., fish, crustaceans, mollusks, and algae) were collected. They were then subjected to high-temperature oxidation using a tube combustion furnace or oxygen bomb combustion devices to isolate CO 2, followed by an analysis of the radioactivity concentration of 14C using LSC. The combustion conditions were optimized by investigating the heating nodes and rates in the oxidation combustion furnace, and the CO 2 collection conditions were optimized by placing a NaOH absorption solution in the oxygen bomb combustion devices. Additionally, the optimal measurement conditions were determined by comparing the effects of varying scintillation cocktails and the dark adaptation time of two preparation methods, i. e., the adsorption and suspension method. Results:When a tubular combustion furnace was used for oxidation and combustion, the optimal heating rate of the sample pyrolysis temperature zone was determined at 1.5℃/min. In this case, the combustion efficiency of various seafood could reach over 95%. When the oxygen bomb combustion devices were employed, placing NaOH solutions both inside and at the exhaust end increased absorption efficiency by 10% compared to the traditional practice of placing a NaOH solution only at the exhaust end. Samples prepared using the absorption method should be kept in the dark for at least 10 h before measurement using LSC, while samples prepared with the suspension methods should be kept for at least 20 h. The results obtained using two preprocessing devices and two sample preparation method were consistent, with a detection limit of 9.10 Bq/kg (dry samples). Compared to the suspension method (The relative standard deviation of the results obtained by two preprocessing devices were 9.00% and 8.27%), the absorption method (the corresponding relative standard deviation were 3.61% and 3.29%) exhibited higher precision in repeated measurements.Conclusions:The aforementioned pretreatment devices and sample preparation method are suitable for determining 14C in seafood.

Objective:To study the applicability of conventional detection method, gamma spectrometry and radiochemical analysis, for the determination of 137Cs activity concentratons in food samples and to compare the difference of such two methods for this purpose. Methods:By using both γ spectrometry and radiochemical analysis, the activity concentrations of 137Cs in different types of food were determined, to compare the required sample amounts, the sample pretreatment and preparation processes and the lower detection limits.With meat samples as a case study, the two method were compared for assessing the activity concentrations of 137Cs in meat samples and evaluating the uncertainties. Results:The deviation of measurement result obtained in meat by using gamma spectrometry and ammonium phosphomolybdate-β counting method is consistent, with relative extended uncertainties of 18.0% and 8.0%, respectively. The pretreatment process for γ spectrometry is characterized by its simplicity, but large sample amount required and time-comsuming process, while the ammonium phosphomolybdate method requires a small amount of sample but in need of separation and purification process.The detection limits of the two methods are 10.6 mBq/kg (sample mass 11.7 kg) and 5.1 mBq/kg (sample sample 2.1 kg ), respectively.Conclusions:The results of two methods for determinationf of the low activity concentrations of 137Cs in food samples are consistent. Therefore, when monitoring low activity concentrations of 137Cs in food samples, the appropriate detection method can be selected based on the specific objective and requirements of the monitoring study.

Objective:To develop a novel magnetic composite nanoparticle with excellent targeting and biocompatibility and verify synergistic magnetic hyperthermia/radiotherapy efficacy in HeLa cells.Methods:Bovine serum albumin(BSA)was used to modify ferroferric oxide(Fe 3O 4)nanoparticles, and then L-selenocystine and folic acid(FA)were coupled on the surface of BSA by carbodiimide method to synthesize magnetic composite nanoparticles Fe 3O 4@BSA@SeCyc2@FA.The as-prepared nanoparticles were characterized to determine the structure, composition, and properties of the nanoparticles to support their biological applications.By evaluating the magnetothermal properties of the as-prepared nanoparticles, analyzing the internalization effect of HeLa cells on the particles and using CellTiter and reactive oxygen species(ROS)kits to detect the cell viability and ROS production of different experimental groups, respectively, the killing and inhibiting effects on HeLa cells were evaluated when hyperthermia was combined with radiotherapy. Results:The average particle size of the Fe 3O 4@BSA@SeCyc2@FA nanoparticles was(19.31 ± 4.84)nm, and the zeta potential was -25.4 mV(pH=7), which indicated that the as-prepared nanoparticles maintained acceptable dispersion and stability for biological experiments.By BSA and FA characteristic absorption peaks combined with the measured content of Se(10.89 μM), L-selenocystine and FA were successfully modified on the surface of the composite nanoparticles.The saturation magnetization value of the Fe 3O 4@BSA@SeCyc2@FA nanoparticles was 47.2 emu/g.The as-prepared nanoparticles maintained the specific absorption rate(SAR)value of 125.4 W/g at the alternating magnetic field of 518 kHz/16 kAm -1, indicating excellent heat generation efficiency(the temperature level ΔT=7 ℃ within 15 min).No significant toxicity was found for HUVEC cells even within the concentration range from 0 to 200 μg/ml and inhibition of cell viability of the HeLa was shown.When magnetic hyperthermia combined with high-energy X-ray, the cell viability of the HeLa decreased significantly to 54.7%, and the intracellular ROS production increased by 108.2% compared with the control group, which showed that the as-prepared nanoparticles significantly enhanced the radiosensitivity of HeLa cells, and the synergistic effect of magnetic hyperthermia combined with radiotherapy was more effective in inhibiting and killing them. Conclusions:The as-prepared nanoparticles show great promise for use as a multifunctional nanoplatform for the synergistic magnetic hyperthermia/radiotherapy to overcome the limitations of monotherapy for cancer treatment.

Objective:To achieve rapid and accurate detection of trace uranium in drinking water by analyzing the factors influencing the accuracy of uranium measurement in drinking water using ultraviolet fluorescence method and by evaluating the uncertainty in measurement.Methods:The influence of acidity, Fe 3+ and Mn 2+ contents on the analitical result were studied to optimize the measurement conditions. The accuracy of the measurement method was verified in 7 laboratories. By studying the errors introduced in the process of standard preparation, sample pretreatment and measurement, the sources of uncertainty were analyzed and the uncertainty was synthesized. Results:At pH 1-11 in aqueous solution, the linear regression coefficient of the standard curve was greater than 0.995, which was in line with the linear measurement range of the instrument. At pH 12 or so, the linear regression coefficient was 0.761, which could not meet the measurement requirements. At pH<3 or pH>10, the increase in fluorescence count was lower, which might increase the measurement error. At Fe 3+ concentration ≥15 mg/L, a large deviation occurred in measurement value that could affect seriously measurement result. At Mn 2+ concentration ≥ 1.6 mg/L, the sample produced white precipitation, which could affect the measurement accuracy. Three spiked water samples with different concentrations were determined in 8 laboratories. Each water sample was measured six times in parallel. The relative standard uncertainty of the result were 6.42×10 -2, 4.48×10 -2 and 5.26×10 -2 μg/L, and the expanded uncertainties were 0.03, 0.06 and 0.12 μg/L( k=2), respectively. Conclusions:The optimum conditions for the determination of uranium in water using this method pH were in samples 3-10, the concentration of Fe 3+ less than 15 mg/L, and the concentration of Mn 2+ less than or equal to 1.6 mg/L. The main sources of uncertainty in the measurement of uranium in water using ultraviolet fluorescence method arise from the repeated measurement error and the volume of added standard solution.

OBJECTIVE：To study the improvement effects of ica riin（ICA）on cognitive function in schizophrenia model rats and its mechanism. METHODS ：SD rats were divided into blank control group ，model group ，ICA low-dose ，medium-dose and high-dose groups （15，30，60 mg/kg）. Except for blank control group ，other groups were given N-methyl-D-aspartate receptor antagonist MK- 801（0.2 mg/kg）intraperitoneally to induce schizophrenia rats models ，once a day ，for consecutive 14 days. After modeling，ICA groups were intragastrically administered with the corresponding drugs ，while blank control group and model group were intragastrically administered with the same volume of water ，once a day ，for consecutive 7 days. The behavioral com changes of rats were detected by Morris water maze test ，open field test ， forced swimming test and Y maze test pathological changes of hippocampus were observed by Nissl staining；the levels of cholinergic indexes [acetylcholine （Ach），choline acetyltransferase （ChAT） and acetylcholinesterase （AchE）] in cerebral tissues were detected by ELISA. The expression of BDNF ，ERK and CREB mRNA in cerebral tissue were detected by RT-PCR ；expression or phosphorylation level of BDNF ，ERK，CREB protein ，apoptosis related proteins （Bcl-2，Bax and Caspase- 3）were detected by Western blot. RESULTS ：Compared with blank control group ，escape latency ，distance at T 1-T3， cumulative immobility time and the expression of Caspase- 3 protein in cerebral tissues were significantly increased in model group （P＜0.05）；the times of crossing platform ，alternation rate ，the number of Nissl staining positive neurons in hippocampus tissues ， the levels of Ach and ChAT in cerebral tissues ，Bcl-2/Bax ratio ，mRNA and protein expression of BDNF ，mRNA expression of ERK and CREB ，the phosphorylation of ERK 1/2 and CREB were significantly decreased （P＜0.05）.Compared with model group ， escape latency ，distance at T 1-T3，cumulative immobility time ，the number of Nissl staining positive neurons ，AchE level in cerebral tissues and relative expression of Caspase- 3 protein were significantly decreased in ICA high-dose group （P＜0.05）；the times of crossing platform ，alternation rate ，levels of Ach and ChAT in cerebral tissues ，Bcl-2/Bax ratio ，mRNA and protein expression of BDNF ，mRNA expression of ERK and CREB ，the phosphorylation of ERK 1/2 and CREB were increased significantly（P＜0.05）. Above indexes in ICA low-dose and medium-dose groups were partially improved significantly than model group（P＜0.05）. CONCLUSIONS ：ICA can improve cognitive function in schizophrenia model rats.Its mechanism may be related to regulating cholinergic system ，inhibiting neuronal apoptosis ，and promoting the expression of BDNF/ERK/CREB signaling pathway.