This study optimized the chemical etching conditions of the newly developed UV-polymerized poly(allyl diglycol carbonate) detector DX-22 and evaluated its detection performance. An orthogonal design followed by single-factor experiments was used to investigate the effects of NaOH concentration, etching temperature, and etching time on track morphology, track density, and background counts. The optimal conditions were 6.5 mol/L NaOH, 65 °C, and 8 h. Under these conditions, etched alpha-particle tracks showed clear contours, relatively uniform morphology, predominantly elliptical shapes, low background, and a track density of 201.8 tracks/mm2. CR-39 was used as a reference detector for indoor radon measurements. DX-22 and CR-39 showed consistent spatial track-density trends, with relative area errors of 6.46%-12.93% between fitted response curves. The field comparison was not intended as an absolute radon calibration, and standardized radon-chamber calibration and uncertainty evaluation remain necessary for quantitative dosimetric application. Overall, DX-22 demonstrated promising potential for radon monitoring and radiation protection.

In order to establish a predictive model for indoor radon concentration in Chinese buildings, walls were constructed using Chinese-style bricks to study the relationship between radon exhalation rates and indoor radon concentrations, as well as the corresponding algorithms. The surface radon exhalation rates of walls with varying thicknesses were measured respectively within the temperature range, when the air conditioning was turned on (17-29 degrees C) and off (4-16 degrees C) in winter by using a closed-loop measurement method. The results indicate that the radon exhalation rate increases with wall thickness for block walls with identical material properties, with the rate of increase being initially rapid before slowing. Furthermore, compared to the 17-29 degrees C range, a smaller wall thickness is required for the exhalation rate to stabilize under the 4-16 degrees C condition. The research obtained the radon exhalation rates that influenced by the block's226Ra content, porosity, wall thickness, and room temperature. The corresponding fitting functions were established for the wall surface radon exhalation rates, which revealed the radon exhalation patterns characteristic of Chinese characteristic block wall in different temperature groups under the conditions of air conditioning on and off in winter.

Radiotherapy is commonly used to treat many cancers, and their sensitivity to radiation is crucial for favorable outcomes. This study investigated whether the immediate early response 5 (IER5) protein affects Cdc25B protein expression in HeLa cells after gamma irradiation. IER5 was knocked down using RNA interference (RNAi) in HeLa cells irradiated with 2 or 4 Gy of gamma rays. The mRNA and protein expression levels were subsequently determined via qRT–PCR and western blotting. The distribution of cells during the cell cycle was also determined using flow cytometry. IER5 protein levels were successfully reduced with RNAi. Variations in IER5 levels led to differences in Cdc25B mRNA and protein levels. Moreover, IER5 affected the proportion of cells in the G2 phase, which is regulated mainly by Cdc25B. Pearson correlation analysis was conducted on the expression levels of IER5 and Cdc25B in HeLa cells and the IER5‐silenced HeLa (siIER5‐HeLa) cell line at various time points after exposure to 4 Gy of gamma rays, and a negative correlation was detected between IER5 and Cdc25B expression levels, with correlation coefficients of −0.686 and −0.663, respectively. Additionally, variations in IER5 levels led to differences in the expression levels of p53, NF‐YB, and p300, which may be putative transcriptional regulators of Cdc25B. These results suggest that IER5 plays a negative role in regulating Cdc25B expression, which may involve interactions with the transcriptional regulators p53, NF‐YB, and p300.

Lymphocyte-activation gene 3 (LAG-3), a next-generation immune checkpoint, has emerged as a promising therapeutic target, but noninvasive tools for evaluating LAG-3 expression remain limited. Herein, we explored an antibody-dependent molecular imaging strategy for noninvasive detection based on a LAG-3-specific antibody, HuL13. The anti-LAG-3 antibody HuL13 was radiolabeled with 124I via electrophilic substitution. LAG-3-expressing A549 cells were constructed by infection with the lentivirus. The specificity and affinity of 124I-HuL13 to LAG-3 receptor were evaluated by cell uptake assay and saturation binding assay. Micro-PET/CT imaging studies were conducted in BALB/c nude mice bearing LAG-3+ A549 tumors. Immunohistochemistry (IHC) validated LAG-3 expression in tumors. The 124I-HuL13 exhibited a good radiochemical yield of 95.59 ± 1.27

Introduction:This study aimed to establish a new predictive model for indoor radon concentrations. Methods:We constructed a radon experimental model using prefabricated block walls and measured surface radon exhalation rates across multi-layer walls. The geometric parameters of various building envelopes (walls, floors, and roofs) were incorporated to calculate indoor radon concentrations from each source. Natural ventilation rates were also considered in developing the indoor radon concentration prediction model. Results:Using closed-loop measurements, we determined the surface radon exhalation rates of prefabricated block walls and established fitting functions for multiple walls under varying temperatures and thicknesses. Based on indoor geometric parameters and natural ventilation rates, we developed a comprehensive prediction model for indoor radon concentrations. The model accurately predicted indoor equilibrium radon concentrations from prefabricated walls (thickness 0.155-0.268 m) at 23 ℃, with deviations less than 10% from measured values within ventilation rates of 0.115±0.015 /h. Conclusions:This scientifically rigorous and practical approach to predicting radon concentration, based on building composition and measurements of radon exhalation rates, enables proactive assessment of indoor radon concentrations and facilitates evidence-based health risk prevention strategies.

The adsorption of Lead (Pb) on brookite titanium dioxide thin films is determined using spin-polarized density functional theory. Band structures as well as density of states are shown. Magnetic irregularities are observed in thin layers that Pb atoms adsorb. The thin film has been identified to have a pivotal thickness of 1.6 nm. Beyond the essential thickness, Pb is unable to cause magnetic anomalies. The atypical magnetic properties stem from the quantum confinement phenomenon and the relaxation of the surface. The film's long-range sequence presents complexity. The positioning of defects is dictated by the concentration of Pb volume rather than its concentration on the surface. The thin film exhibits a pivotal interaction range of 1.0 nm. A gap between two neighboring spins can lead to fluctuations in the magnetic configuration's stability or instability, contingent on the Pb volume concentration. If not, the impact of long-range order is minimal, and the stability between magnetic and non-magnetic setups is nearly identical.

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 radon-containing water.

The decay of radon gas in soil and buildings produces alpha radiation, which is the second leading cause of lung cancer in humans. Therefore, by conveniently detecting radon gas in the environment, potential sources of danger can be identified early, and necessary measures can be taken to protect human health. Solid-state nuclear track detectors prepared from polyallyl diglycol carbonate (PADC) resin are the most sensitive detectors for alpha radiation released by radon gas. The traditional method of preparing PADC resin involves free radical thermal polymerization, which suffers from issues such as low polymerization efficiency, long processing time, and the occurrence of defects in the product. In this study, PADC resin was efficiently prepared using a UV initiator. Starting from the polymerization mechanism, experiments were designed using a controlled variable approach, and a rational polymerization apparatus was devised. By comparing the double bond conversion rate, transparency, hardness, and yellowness index of the polymers, the optimal initiator for PADC resin, 2-hydroxy-2-methyl-1-phenyl-1-propanone (1173), was selected. The influence of irradiation intensity, irradiation time, and UV initiator dosage was investigated. The performance of the polymers, including double bond conversion rate, optical properties, dynamic mechanical properties, etching rate, and track detection efficiency, was analyzed. The experimental conditions for preparing PADC resin were optimized: irradiation intensity of 12 mW/cm2, irradiation time of 25 min, and UV initiator dosage of 5 parts. The resulting resin polymer had a double bond conversion rate of 93.2% and a track detection efficiency of 0.714.

Introduction:Radon (222Rn or 222radon) is a radioactive gas emitted from building materials, foundations, and soil. Children are especially susceptible to radon exposure, underscoring the need to assess indoor radon levels in kindergartens. This study monitored radon concentrations in 37 Beijing kindergartens from June to October 2023.Methods:A random sample of 37 kindergartens was selected from 18 administrative districts in Beijing. The indoor radon concentration was measured using the solid track accumulation method, with radon detectors continuously monitored over a 3-month period.Results:The mean indoor radon level in 37 kindergartens, observed at 252 monitoring points, was 84.3 Bq/m3, with values varying from 12.9 to 263.5 Bq/m3. About 20.2% of points showed radon levels between 100.0 and 200.0 Bq/m3, while 2.4% exceeded 200.0 Bq/m3. Notably, radon levels were significantly elevated on the ground floor compared to the upper floors.Conclusion:Indoor radon levels in 37 kindergartens remained below the national standard limit of 300.0 Bq/m3 for buildings (GB/T 16146-2015). Nonetheless, 18.9% of the kindergartens exceeded the 100.0 Bq/m3 limit set for new constructions. It is advised to improve radon monitoring in kindergartens and consider developing a national standard for maximum permissible radon levels in such facilities.

Introduction:Traditional methods for determining radiation dose in nuclear medicine include the Monte Carlo method, the discrete ordinate method, and the point kernel integration method. This study presents a new mathematical model for predicting the radiation dose rate in the vicinity of nuclear medicine patients. Methods:A new algorithm was created by combining the physical model of "cylinder superposition" of the human body with integral analysis to assess the radiation dose rate in the vicinity of nuclear medicine patients. Results:The model accurately predicted radiation dose rates within distances of 0.1-3.0 m, with a deviation of less than 11% compared to observed rates. The model demonstrated greater accuracy at shorter distances from the radiation source, with a deviation of only 1.55% from observed values at 0.1 m. Discussion:The model proposed in this study effectively represents the spatial and temporal distribution of the radiation field around nuclear medicine patients and demonstrates good agreement with actual measurements. This model has the potential to serve as a radiation dose rate alert system in hospital environments.

Lymphocyte activation gene 3 (LAG-3) has attracted much attention as a potentially valuable immune checkpoint. Individual identification of LAG-3 expression at screening and during treatment could improve the successful implementation of anti-LAG-3 therapies. HuL13 is a human IgG1 monoclonal antibody that binds to the LAG-3 receptor in T cells. Here, we used [89Zr]Zr-labeled HuL13 to delineate LAG-3+ T-cell infiltration into tumors via positron emission tomography (PET) imaging. A549/LAG-3 cells, which stably express LAG-3, were generated by infection with lentivirus. The uptake of [89Zr]Zr-DFO-HuL13 in A549/LAG-3 cells was greater than that in the negative control (A549/NC) cells at each time point. The equilibrium dissociation constant (Kd) of [89Zr]Zr-DFO-HuL13 for the LAG-3 receptor was 8.22 nM. PET imaging revealed significant uptake in the tumor areas of A549/LAG-3 tumor-bearing mice from 24 h after injection (SUVmax = 2.43 ± 0.06 at 24 h). As a proof of concept, PET imaging of the [89Zr]Zr-DFO-HuL13 tracer was further investigated in an MC38 tumor-bearing humanized LAG-3 mouse model. PET imaging revealed that the [89Zr]Zr-DFO-HuL13 tracer specifically targets human LAG-3 expressed on tumor-infiltrating lymphocytes (TILs). In addition to the tumors, the spleen was also noticeably visible. Tumor uptake of the [89Zr]Zr-DFO-HuL13 tracer was lower than its uptake in the spleen, but high uptake in the spleen could be reduced by coinjection of unlabeled antibodies. Coinjection of unlabeled antibodies increases tracer activity in the blood pool, thereby improving tumor uptake. Dosimetry evaluation of the healthy mouse models revealed that the highest absorbed radiation dose was in the spleen, followed by the liver and heart wall. In summary, these studies demonstrate the feasibility of using the [89Zr]Zr-DFO-HuL13 tracer for the detection of LAG-3 expression on TILs. Further clinical evaluation of the [89Zr]Zr-DFO-HuL13 tracer may be of significant help in the stratification and management of patients suitable for anti-LAG-3 therapy.

This study investigates the expression and clinical relevance of the immediate early response 5 (IER5) protein in various gastrointestinal cancers, including esophageal squamous cell carcinoma, gastric adenocarcinoma, colorectal adenocarcinoma and hepatocellular carcinoma. Western blot and immunohistochemistry analyses were conducted to compare the IER5 protein levels in tumour tissues with adjacent normal tissues. The results indicate that IER5 protein expression is significantly higher in tumour tissues across all the examined cancer types, and the increase in cytoplasmic IER5 expression in these cancers suggests its potential involvement in tumorigenesis. However, this study's clinicopathological analysis did not find a correlation between IER5 expression and patients' age, sex, clinical stage and lymph node metastasis status in all the examined cancer types, as well as HBsAg positivity and cirrhosis in HCC. In conclusion, IER5 is overexpressed in gastrointestinal tumour tissues and could be a promising marker and target for cancer diagnosis and treatment.

BackgroundAcute hematologic toxicity (HT) is a prevalent adverse tissue reaction observed in cervical cancer patients undergoing chemoradiotherapy (CRT), which may lead to various negative effects such as compromised therapeutic efficacy and prolonged treatment duration. Accurate prediction of HT occurrence prior to CRT remains challenging.MethodsA discovery dataset comprising 478 continuous cervical cancer patients (140 HT patients) and a validation dataset consisting of 205 patients (52 HT patients) were retrospectively enrolled. Both datasets were categorized into the CRT group and radiotherapy (RT)-alone group based on the treatment regimen, i.e., whether chemotherapy was administered within the focused RT duration. Radiomics features were derived by contouring three regions of interest (ROIs)—bone marrow (BM), femoral head (FH), and clinical target volume (CTV)—on the treatment planning CT images before RT. A comprehensive model combining the radiomics features as well as the demographic, clinical, and dosimetric features was constructed to classify patients exhibiting acute HT symptoms in the CRT group, RT group, and combination group. Furthermore, the time-to-event analysis of the discriminative ROI was performed on all patients with acute HT to understand the HT temporal progression.ResultsAmong three ROIs, BM exhibited the best performance in classifying acute HT, which was verified across all patient groups in both discovery and validation datasets. Among different patient groups in the discovery dataset, acute HT was more precisely predicted in the CRT group [area under the curve (AUC) = 0.779, 95% CI: 0.657–0.874] than that in the RT-alone (AUC = 0.686, 95% CI: 0.529–0.817) or combination group (AUC = 0.748, 95% CI: 0.655–0.827). The predictive results in the validation dataset similarly coincided with those in the discovery dataset: CRT group (AUC = 0.802, 95% CI: 0.669–0.914), RT-alone group (AUC = 0.737, 95% CI: 0.612–0.862), and combination group (AUC = 0.793, 95% CI: 0.713–0.874). In addition, distinct feature sets were adopted for different patient groups. Moreover, the predicted HT risk of BM was also indicative of the HT temporal progression.ConclusionsHT prediction in cervical patients is dependent on both the treatment regimen and ROI selection, and BM is closely related to the occurrence and progression of HT, especially for CRT patients.

目的:采用瓦里安加速器机载千伏级锥形束CT(kV-CBCT)对模体进行标准胸部扫描,测量不同次数影像引导下的胸部肿瘤周围危及器官(OAR)的吸收剂量,从而评估患者在整个放射治疗期间影像引导所致的OAR吸收剂量.方法:选用一致性≤±2％的热释光剂量计(TLD)并在标准剂量实验室刻度,将其放置在Anderson Rando模体的预留插孔内,在kV-CBCT标准胸部扫描条件下,测量OAR在单次和5次影像引导下的吸收剂量,并以此计算器官当量剂量.结果:单次kV-CBCT扫描条件下照射野内器官的吸收剂量范围在0.519～3.915 mGy,5次kV-CBCT扫描条件下照射野内器官的吸收剂量范围在1.436～17.971 mGy.其中心脏的吸收剂量最高,单次kV-CBCT扫描下的吸收剂量为3.915 mGy,5次kV-CBCT扫描下的吸收剂量为17.971 mGy;甲状腺右侧叶的吸收剂量最低,单次kV-CBCT扫描下的吸收剂量为0.519 mGy,5次kV-CBCT扫描下的吸收剂量为1.436 mGy.感兴趣器官中左肺、右肺、心脏、甲状腺左侧、甲状腺右侧、左乳腺和右乳腺在不同辐照次数之间,TLD信号值的差异有统计学意义(Z=-12.120,Z=-10.574,Z=-39.202,Z=-5.716,Z=-13.483,Z=-20.838,Z=-42.698;P<0.05).结论:多次影像引导条件下,OAR的累积吸收剂量不可采用单次剂量与影像引导次数的乘积计算,kV-CBCT影像引导下OAR剂量测定方法可为放射治疗患者在影像引导期间OAR累积吸收剂量的计算提供理论依据.

Human activities increase the risk of stable and radioactive strontium (Sr) isotopes entering the environment and food chain. In this study, the effects of Sr on the nutrient uptake and physiological responses of lettuce under different “Sr treatment” concentrations (0, control, 1, 2, 3, 4, and 5 mM) and “times” (7, 14, and 21 day) were studied in a hydroponic system. In addition, the distribution of Sr on the surfaces and cross-sections of lettuce leaves was revealed by scanning electron microscopy with energy-dispersive X-ray (SEM–EDX) analysis. A two-way analysis of variance (ANOVA) method was used to analyze the significance of “Sr treatment,” “time,” and their “interaction.” The results showed that an increase in Sr uptake in lettuce could significantly reduce the uptake of calcium (Ca). The contents of sulfur (S), potassium (K), and iron (Fe) in lettuce leaves showed significant differences with the sampling day. Similarly, the fresh weight of lettuce leaves and roots as well as the photosynthetic pigment contents of lettuce leaves was also significantly different with the sampling day. The activities of antioxidant enzymes (superoxide dismutase (SOD), catalase (CAT), and peroxidase (POD)) showed significant differences with the sampling day. The activities of SOD and CAT decreased significantly with the sampling day, while POD increased significantly. The MDA content increased significantly with increasing hydroponic Sr concentration on the 21st day. SEM–EDX analysis showed that the weight percentage of Sr in the vascular bundle sheath in the cross-section of lettuce leaves was relatively higher than that in the mesophyll. This study aids our understanding of the distribution of Sr in lettuce leaf tissues and the effect of Sr on lettuce physiology.

A granite fracture filling material (FFM) collected from a candidate high-level radioactive waste (HLRW) geological disposal was used to evaluate the sorption behavior of 90Sr. The sorption process was fitted with the Henry and Freundlich models, and the distribution coefficient (Kd) values ranged between 117.4 and 434.8 mL/g, according to the batch experimental results. Furthermore, the Kd value and sorption percentage were affected by the initial solution specific activity, pH, FFM particle size, bicarbonate ion content and solid-to-liquid ratio. This work provides important information for the geological barrier of the repository. A granite fracture filling material sample collected from a HLRW geological disposal. The sorption process was fitted using the isotherm models of Henry and Freundlich. The main factors affecting the sorption of 90Sr were discussed.

目的 探索PET/CT心肌代谢显像受检者周围辐射剂量水平,为保证周围人员辐射安全提供数据支持.方法 选取33例行18F-FDG PET/CT心肌代谢显像患者,在受检者胸部等高位置按照不同体位方向、时间和距离处对其周围剂量当量率进行测量,探索受检者周围剂量当量率的分布规律.结果 在相同测量时间和距离下,受检者身体两侧的周围剂量当量率相比正、背面更低.受检者注射18F-FDG显像剂后,距离体表1 m处正面的周围剂量当量率为13～21 μSv/h,检查结束后降至5～14 μSv/h,平均降低46％.受检者周围剂量当量率随距离(10～300 cm)的增加呈幂函数趋势降低,其幂指数均值为-1.2.结论 心肌代谢显像受检者注射药物后周围辐射水平较高,周围剂量当量率随时间和距离增加快速降低,建议心肌代谢显像受检者检查当天避免与他人长时间、近距离接触.

目的 了解我国中小学校开设健康教育相关课程的状况及影响因素,为促进我国学校卫生建设提出意见和建议.方法 采用x2检验进行组间比较,构建二元Logistic回归模型识别影响开课因素,分析不同因素对开展卫生相关课程/讲座的影响.结果 本次调查共收集了全国31个省、自治区、直辖市及新疆生产建设兵团总计193 392所学校的相关数据,共覆盖学生151 327 628人.中小学的健康教育的开课率为90.13％.多因素分析结果显示:东部和西部地区相对于中部地区开课率较高(东部:AOR为1.16,95％CI:1.12～1.21;西部:AOR 为 1.13,95％CI:1.08～1.18).中学比小学开课率高(AOR 为 1.31,95％CI:1.24～1.38).寄宿制、学校人数大于等于600人的非寄宿制相对于人数少于600人的非寄宿制开课率高(寄宿制:AOR为2.12,95％CI:2.00～2.23;大于等于600人的非寄宿制:AOR为1.98,95％CI:1.89～2.07).配备保健教师、保健室、校医、卫生室的都有利于学校卫生健康相关课程或讲座的开展(保健教师:AOR为4.53,95％CI:4.35～4.72;保健室:AOR为 1.34,95％CI:1.28～1.39;校医:AOR为2.24,95％CI:2.09～2.40;卫生室:AOR 为 1.25,95％CI:1.18～1.33).结论 目前全国中小学健康教育课总体开课率较高,但在不同经济发展地区、不同学段、不同寄宿制类型卫生保健情况区别明显.在政策制定中,需要因地制宜,因人(学校类别)制宜.

Objective To examine the status of doctors and clinics allocation in public primary and secondary schools across the mainland of China for providing a reference to the formulation of school health strategies. MethodsWith Epidemiological Dynamic Data Collection Platform (EDDC) of the Chinese Center for Disease Control and Prevention, we conducted a general survey on school doctors and clinics allocation among primary and secondary schools across 30 provincial-level administrative divisions in the mainland of China from October 2019 to February 2020. ResultsAmong the 193 492 public primary and secondary schools surveyed, 33 407 (17.27%) had school doctors and there were 44 881 school doctors providing healthcare services to 155 143 857 students in 2019, with a student-school doctor ratio of 3457 : 1. Of the 66 682 surveyed schools with the total student number of 600 and above, only 1 296 (1.94%) met the national standard (≤ 600 : 1) for the student-school doctor ratio. School clinics were set up in 15.41% (n = 29 809) of all schools surveyed. There were statistical disparities in allocations of part/full time school doctors and school clinics, student-school doctor ratio, proportions of the school doctors taking professional training programs/refresher courses among the schools in different regions and the schools of various types (primary/secondary/vacation school and boarding/non-boarding) (all P < 0.01). ConclusionThere were significant deficits in allocations of school doctors and clinics among primary and secondary schools across China and region- and school type-specific measures should be taken to improve the situation.

目的 分析我国职业卫生技术服务甲级机构人员、工作场所、仪器设备、标准物质、技术服务能力、质量管理体系现状和存在问题,为提高我国职业卫生技术服务能力提供对策建议.方法 对2021年3-4月申请甲级资质延续、变更或增加业务范围的84家甲级机构的技术评审结果进行分析.结果 全国甲级机构东部地区数量较多;申请第一类、第二类和同时申请2类业务范围的机构分别占68％、4％和27.85％;第一类业务范围检测项目物理因素和通风工程批准率较低;现场技术考核仪器设备和标准物质、技术服务能力、质量管理体系合格率低于90％,东、中、西部差异不明显;共617人次通过专业技术能力考核评估.结论 加强职业卫生技术服务机构的事中事后监管,提高职业危害因素检测和评价能力,加强专业技术人员人才队伍建设.