The repair of bone defects is heavily influenced by the dynamic osteogenic microenvironment. Static scaffolds constructed by traditional 3D printing technology cannot simulate the dynamic nature of the microenvironment during bone defect repair due to the fixed structure, uncontrollable release of active factors, and difficult regeneration of blood vessels, among other factors. Breaking through the limitations of these static scaffolds and realizing the intelligent and dynamic regulation of the osteogenic microenvironment is a key scientific issue in the field of bone tissue engineering. 4D printing technology combines the dynamic responsiveness of bone restoration materials with the concept of intelligent design to regulate the micro and macro structure of scaffolds. This technology provides a new method for bone tissue engineering by responding to endogenous and exogenous stimuli and creating a better osteogenic microenvironment through functionalized design, including drug delivery and antibacterial function. However, this technology currently suffers from challenges related to dynamic response material design, insufficient precision of printing technology, and mismatches between multi-stimulus response systems, metabolic rhythms of bone tissue, and functionalized composite scaffolds. Future research should focus on the development of smart response materials with excellent dynamic responses and bioactivity, the creation of new printing technologies, and the design of personalized and precise bone repair solutions. The aim of this paper is to review the current research status of 4D printing for bone tissue engineering in terms of material types, response mechanisms, and applications to provide a theoretical basis for the development and clinical application of functional bone repair materials in the future.

Objective To investigate the levels of radionuclides in food in Beijing, China, and assess the committed effective dose to local residents from food intake. Methods From 2021 to 2022, a total of 65 food samples across 7 categories were collected in Beijing. The activity concentrations of radionuclides, including ¹³⁷Cs, ²¹⁰Pb, ²³⁸U, ²²⁸Ra, ²²⁶Ra, ⁴⁰K, ⁹⁰Sr, ²¹⁰Po, ³H and ¹⁴C, were measured using gamma spectrometry and radiochemical methods. By combining the monitoring results with dietary consumption data of Beijing residents and the internal dose coefficients for Chinese reference adult phantom, the committed effective dose was estimated. Results The levels of radionuclides in food in Beijing were within the normal background range, consistent with related surveys in China and abroad, with activity concentrations below national standard limits. No significant differences were found in the activity concentrations of ¹³⁷Cs, ²³⁸U, ²²⁸Ra, ²²⁶Ra and ⁴⁰K between food samples collected from key areas and those from control areas (P > 0.05). The committed effective doses calculated according to internal dose coefficients for Chinese reference adult male phantom and GB 18871-2002 were 0.26 mSv and 0.19 mSv, respectively. Based on the Chinese reference adult male phantom, the majority of the committed effective dose was attributed to ²¹⁰Pb (45.1%), ²²⁸Ra (37.1%), ²¹⁰Po (12.3%), and ²²⁶Ra (4.7%). Conclusion The levels of radionuclides in food in Beijing fluctuated within the background range, resulting in a low radiation dose burden to the population.

Metastatic dissemination is the major cause of death from breast-cancer (BC). Fusobacterium nucleatum (F.n) is widely enriched in BC and has recently been identified as one of the high-risk factors for promoting BC metastasis. Here, with an experimental model, we demonstrated that intratumoral F.n induced BC aggressiveness by transcriptionally activating Epithelial-mesenchymal transition-associated genes. Therefore, the F.n may be a potential target to prevent metastasis. Given the fact that cancer-associated fibroblasts (CAFs) are abundant in BC and located near blood vessels, we report an optogenetic system that drives CAF to in situ produce human antibacterial peptide LL37, with the characteristics of biosafety and freely intercellular trafficking, for depleting intratumoral F.n, leading to a 72.1% reduction in lung metastatic nodules number without affecting the balance of the systemic flora. Notably, mild photothermal treatment was found that could normalize CAF, contributing to synergistically inhibiting BC metastasis. In addition, the system can also simultaneously encode a gene of TNF-related apoptosis-inducing ligand to suppress the primary tumor. Together, our study highlights the potential of local elimination of tumor pathogenic bacteria to prevent BC metastasis.

Objective To observe the daily bladder and bowel preparation of patients with prostate cancer by cone-beam computed tomography (CBCT), and analyze its impact on the precise implementation of radiotherapy for prostate cancer and side effects. Methods We retrospectively analyzed 38 patients with prostate cancer who underwent volumetric modulated arc therapy. The number of radiation fractions for each patient ranged from 25 to 35. A CBCT scan was performed before each daily radiation therapy, and the number of scans for each patient ranged from 25 to 40. Setup errors were adjusted to ensure that the tumor was targeted and the rectum wall was not in the high-dose target area of the prostate. There were 93 instances where treatment could not be successfully implemented and re-preparation and re-scanning were required. We calculated the success rate of treatment and setup errors, compared radiotherapist-adjusted error values under different bladder and bowel preparation conditions, and recorded radiotherapy-related side effects. Results The success rate of treatment in the 38 patients was (92.14 ± 5.25)%. Among the 93 instances of seriously inadequate preparation, 48.4% were due to insufficient bladder filling, and 30.1% were due to intestinal bloating. Radiotherapy side effects were negatively correlated with the success rate of treatment (r = −0.393, P = 0.015). When bladder filling was sufficient, there were no significant differences in radiotherapist-adjusted error values in the left-right (LR), superior-inferior (SI), and anterior-posterior (AP) directions between adequate and inadequate bowel preparation (P > 0.05). When the bladder was moderately or insufficiently filled, there were significant differences in radiotherapist-adjusted error values in the LR, SI, and AP directions between adequate and inadequate bowel preparation (P < 0.05). Conclusion Insufficient bladder filling and intestinal bloating are the main factors influencing the successful implementation of radiotherapy for prostate cancer. When the bladder is sufficiently filled, bowel preparation does not affect prostate position change.

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.

Objective:To assess the predictive value of dosiomics in predicting the occurrence of bone marrow suppression (BMS) in patients with pelvic tumors during radiotherapy.Methods:A retrospective analysis was conducted on the clinical data and radiotherapy planning documents of 129 patients with pelvic region tumors who underwent radiotherapy at the First Affiliated Hospital of Nanjing Medical University from January 2019 to January 2023. The region of interest (ROI) was outlined for bone marrow in the pelvic region by Accu Contour software in planning CT, and the ROI was exported together with the dose distribution file. According to a stratified randomization grouping method, the patients were divided into the training set and test set in an 8 vs. 2 ratio. The dosiomic features were extracted from the ROI, and the two independent samples t-test and the least absolute shrinkage and selection operator (LASSO) algorithm was employed to identify the best predictive characteristics. Subsequently, the dosiomic scores were calculated. Clinical predictors were identified through both univariant and multivariate logistic regression analyses. Predictive models were constructed by using clinical predictors alone and combining clinical predictors and dosiomic scores. The efficacy of predictive model was assessed by plotting the receiver operating characteristic (ROC) curve and evaluating its performance through the area under the ROC curve (AUC), the calibration curve, and decision curve analysis (DCA). Results:Fourteen dosiomic features that showed a strong correlation with the occurrence of BMS were screened and utilized to calculate the dosiomic scores. Based on both univariant and multivariate logistic regression analyses, chemotherapy, planning target volume (PTV) and V 5 Gy were identified as clinical predictors. According to the combined model, the AUC values for the training set and test set were 0.911 and 0.868, surpassing those of the clinical model (AUC=0.878 and 0.824). Furthermore, the analysis of both the calibration curve and DCA suggested that the combined model had higher calibration and net clinical benefit. Conclusion:The combined model has a high diagnostic value for predicting BMS in patients with pelvic tumors during radiotherapy.

Objective To investigate the method of tube furnace oxidation combustion and liquid scintillation counting for the determination of carbon-14 in seafood, and to provide technical support for the monitoring of carbon-14 in seafood. Methods By studying the pyrolysis characteristics of five types of dried seafood samples, including yellow croaker, white shrimp, swimming crab, clam, and seaweed, a temperature control program suitable for the oxidation combustion of seafood was established. The combustion efficiency, carbon element recovery rate, and the accuracy and precision of the method were determined. Results The combustion efficiency was more than 98% for most seafood using the recommended combustion program. The recovery rate of carbon was similar to that calculated by glucose combustion; both were more than 95%. Four laboratories validated the accuracy of the method by measuring the carbon-14 activity concentration in the Chinese sugar carbon standard material. The relative errors ranged from 1.03% to 3.41% and the average relative error was 2.36%. The precision of this method was verified by measuring the carbon-14 activity concentration in yellow croaker samples. The within-laboratory relative standard deviation ranged from 5.11% to 9.35% and the between-laboratories relative standard deviation was 4.04%. Conclusion The tube furnace oxidation combustion and liquid scintillation counting method was used to determine the activity concentration of carbon-14 in seafood. The recommended oxidation combustion program is more targeted and less time-consuming. The accuracy and precision of this method meet the requirements. This method is suitable for the determination of carbon-14 in seafood.

Background ¹³⁷Cs in atmospheric aerosol is the product of past nuclear weapon tests and nuclear accidents. When ¹³⁷Cs is released into the atmosphere, it will deposit in dry land and marine environment, causing pollution of soil surface, water, agricultural products, and animal byproducts, and affecting public health. Objective To identify the variation pattern of ¹³⁷Cs activity concentration in aerosol and its correlation with dust concentration in Beijing area from 2017 to 2020. Methods A total of 958 aerosol samples were collected from November 1, 2017 to June 30, 2020 in Beijing with a high volume air sampler at a sampling flow rate about 600 m³·h⁻¹ and a collection time for each sample about 24 h. The activity concentration of ¹³⁷Cs in the aerosol samples was determined with a low-background high-purity germanium γ spectrometer. The dust concentration was calculated using the difference in the mass of the aerosol filter before and after sampling. The detection rate of ¹³⁷Cs and dust concentration in different seasons were compared. Spearman rank correlation test was used to analyze the correlation between ¹³⁷Cs activity concentration and dust concentration. Results From 2017 to 2020, the ¹³⁷Cs activity concentrations of 33 from 958 aerosol samples in Beijing were above the minimum detectable activityconcentration, the overall detection rate of ¹³⁷Cs was 3.4%, and the activity concentration ranged from 1.86 to 45.53 μBq·m⁻³, with a median value of 4.85 μBq·m⁻³. The detection rate of ¹³⁷Cs was highest in spring, followed by autumn, and lowest in winter and summer (8.4%, 3.0%, 1.1%, and 0.5%, respectively). The dust concentration ranged from 0.03 to 1.55 mg·m⁻³, with an average value of 0.18 mg·m⁻³. There was a statistically significant difference in the dust concentrations in spring, summer, autumn, and winter (F=45.51, P<0.05), and the highest value was 0.24 mg·m⁻³ in spring (P<0.05). The ¹³⁷Cs activity concentration was positively correlated with the dust concentration (P<0.05). Conclusion The ¹³⁷Cs activity concentration in aerosol in Beijing from 2017 to 2020 fluctuates within the range of background level, and its activity concentration is highest in spring, followed autumn, and lowest in summer and winter.

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.

Objective:To analyze the causal relationship between gut microbiota and gestational diabetes,and to clarify its mechanism.Methods:Two-sample Mendelian randomization(MR)analysis was conducted by using summary data from genome-wide association study(GWAS)for gut microbiota and gestational diabetes.The GWAS data of gut microbiota were obtained from a GWAS study from the MiBioGen consortium;the GWAS data on gestational diabetes were sourced from the FinnGen consortium's publicly available R8 dataset;inverse variance weighted(IVW)method was used as the primary method to detect the causal association between the gut microbiota and the gestational diabetes.Sensitivity analysis was performed by Weighted Median and MR Egger methods;heterogeneity and pleiotropy were detected by Cochran's Q,MR-PRESSO,Egger intercept tests and Leave-One-Out analysis;multivariable MR was used to adjust for the effect of body mass index(BMI);reverse MR was used to explore the presence of reverse causal associations;Gene Ontology(GO)fuctional and Kyoto Encyclopedia of Genes and Genomes(KEGG)signaling enrichment analyses were used to explore the potential pathways through which gut microbiota may have impact on gestational diabetes.Results:Four gut microbes were found to be causally associated with gestational diabetes:the genus Methanobrevibacter and the phylum Euryarchaeota displayed negative causal relationships with the risk of gestational diabetes,while the genus Olsenella and genus Lachnoclostridium exhibited positive causal associations.No significant heterogeneity or horizontal pleiotropy was detected in the analysis.The reverse MR analysis did not reveal any causal relationship.After adjusting for BMI,the multivariable MR analysis results showed there were the causal associations between the genus Olsenella and the phylum Euryarchaeota with the risk of gestational diabetes.The GO fuctional and KEGG signaling pathway enrichment analyses results showed that axon development,axon production,insulin secretion and other pathways were significantly enriched.Conclusion:There are causal associations between four gut microbes and gestational diabetes.Among them,the significant correlations with gestational diabetes are still observed in phylum Euryarchaeota and genus Olsenella after adjusting for BMI.