Objective:To investigate the radiation field distribution characteristics in a 9 MeV electron FLASH (e-FLASH) linear accelerator treatment room.Methods:The Geant4 Monte Carlo program was employed for physical simulating of the radiation field distribution inside and outside the treatment room under a single-beam delivery condition with a total dose of 50 Gy at the reference point and a dose rate of 250 Gy/s. High-sensitivity radiation detectors (AT1123) were used to validate the measurements at key points.Results:The dose rate at the reference point was approximately 9×10 11 μSv/h. Due to the scattering and shielding effects, the deviation of the attenuation rate from the inverse-square law was observed and the isodose lines exhibited spatial drift. Measured dose rates at key points showed good agreement with the simulation result, with a maximum deviation within 30%. Conclusions:The complex radiation field distribution can be effectively simulated using Geant4 in an e-FLASH treatment room. This indicated the Geant4 is not only applicable for the shielding calculations in e-FLASH radiotherapy facilities, but also for the design optimization through, reduction of trial-and-error iterations and engineering costs.

Objective:To investigate the radiation field distribution characteristics in a 9 MeV electron FLASH (e-FLASH) linear accelerator treatment room.Methods:The Geant4 Monte Carlo program was employed for physical simulating of the radiation field distribution inside and outside the treatment room under a single-beam delivery condition with a total dose of 50 Gy at the reference point and a dose rate of 250 Gy/s. High-sensitivity radiation detectors (AT1123) were used to validate the measurements at key points.Results:The dose rate at the reference point was approximately 9×10 11 μSv/h. Due to the scattering and shielding effects, the deviation of the attenuation rate from the inverse-square law was observed and the isodose lines exhibited spatial drift. Measured dose rates at key points showed good agreement with the simulation result, with a maximum deviation within 30%. Conclusions:The complex radiation field distribution can be effectively simulated using Geant4 in an e-FLASH treatment room. This indicated the Geant4 is not only applicable for the shielding calculations in e-FLASH radiotherapy facilities, but also for the design optimization through, reduction of trial-and-error iterations and engineering costs.

Circular RNA (circRNA) has shown great application potential in triple-negative breast cancer (TNBC). The aberrantly expressed circRNAs participate in the occurrence and development of TNBC by acting as microRNA sponges, regulating gene expression, interacting with functional proteins, and encoding short peptides or proteins to regulate the biological processes of TNBC cell proliferation, apoptosis, invasion, metastasis, and drug resistance. circRNAs are emerging biomarkers for early diagnosis and prognosis of TNBC, as well as new therapeutic targets with potential clinical value. Further elucidation of the complex mechanism of circRNAs in TNBC may provide an important theoretical basis for the development of precise therapeutic strategies for TNBC.

Objective:To investigate the risk factors of intraspinal cement leakage in the treatment of osteoporotic vertebral compression fracture by percutaneous vertebroplasty (PVP).Methods:From January 2018 to December 2021, 156 patients with OVCF who received surgical treatment in Beijing Tongzhou Integrated Traditional Chinese and Western Medicine Hospital were enrolled in this retrospective case-control study. The postoperative CT imaging results were analyzed, and the patients were divided into two groups according to the occurrence of intraspinal cement leakage: leakage group ( n=28) and non-leakage group ( n=128). Measurement data was expressed as mean±standard deviation ( ± s), and t-test was used for comparison of visual analogue score (VAS) between groups; the count data was expressed as the number of cases and percentage (%); univariate and multivariate Logistic regression analysis were used to evaluate the risk factors of postoperative intraspinal cement leakage. Results:All the patients were treated by PVP successfully, without obvious adverse reactions and serious complications occurred during and after the operation. Univariate Logistic regression analysis showed that higher bone mineral density ( P=0.005), OVCF combined with posterior vertebral wall injury ( P<0.001) and higher bone cement dosage ( P=0.013) were the risk factors leading to intraspinal cement leakage. Multivariate Logistic regression analysis showed that higher bone mineral density ( P=0.009, 95% CI: 0.152-0.762, OR=0.340), OVCF combined with posterior vertebral wall injury ( P=0.001, 95% CI: 2.134-15.780, OR=5.803), and higher bone cement dosage ( P=0.005, 95% CI: 1.175-2.505, OR=1.715) were the independent risk factors of intraspinal cement leakage. Conclusion:Intraspinal cement leakage was common complication after PVP. Higher bone mineral density, OVCF combined with posterior vertebral wall injury, and higher bone cement dosage were the independent risk factors affecting intraspinal cement leakage.

Optical coherence elastography (OCE) is a novel technique developed in recent years to investigate the biomechanical properties of tissues, similar to optical coherence tomography angiography, a functional version of optical coherence tomography.OCE utilizes load excitation to detect the mechanical response of ocular tissues, facilitating quantitative analysis of stress-strain curves, Young's modulus, and other biomechanical indicators.It also generates two-dimensional/three-dimensional elastic maps of the tissues.With its noninvasive, high-resolution, real-time, rapid, and three-dimensional imaging capabilities, OCE provides both structural and mechanical information about ocular tissues, opening up new dimensions in ocular disease diagnosis and pathogenesis research.This article introduced the technical classification and research status of OCE, and highlighted its research progress in ophthalmology, including its applications in assisted refractive surgery design, keratoconus patient screening, assessment of corneal cross-linking surgery efficacy, cataract diagnosis and grading, measurement of retinal biomechanics, and research into myopia pathogenesis.The challenges and opportunities for clinical translation of OCE in ophthalmology were also discussed.

The interaction between breast cancer cells and the tumor microenvironment plays a vital role in the occurrence and development of breast cancer. Cancer-associated fibroblasts are heterogeneous stromal cells that are abundant in the tumor microenvironment. They participate in tumor angiogenesis, treatment resistance and distant metastasis by secreting a variety of cytokines, growth factors and chemokines. It has great potential as a biomarker for targeted therapy and clinical prognosis of breast cancer, and it can also provide new ideas for adjuvant treatment of breast cancer.

OBJECTIVE: To compare the diagnostic efficacy among three RT-PCR test kits for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) nucleic acid detection. METHODS: The throat swab samples from 40 hospitalized patients clinically diagnosed as coronavirus disease 2019 (COVID-19) and 16 hospitalized non-COVID-19 patients were recruited. The SARS-CoV-2 nucleic acid was detected in throat swab samples with RT-PCR test kits from Sansure Biotech ("Sansure" for short), Jiangsu Bioperfectus Technologies ("Bioperfectus" for short) and BGI Genomics ("BGI" for short). The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and Kappa value were analyzed. The viral nucleic acid was extracted from the throat swab samples by one-step cleavage and magnetic bead methods, and the efficacy of two extraction methods was also compared. The results of magnetic bead method for nucleic acid extraction by two different extractors (Sansure Natch CS S12C Fully Automated Nucleic Acid Extraction System vs. Tianlong NP968-C Nucleic Acid Extractor) were also compared. RESULTS: The sensitivity, specificity, PPV, NPV and kappa value were 95.00%, 87.50%, 95.00%, 87.50%and 0.825 for Sansure kit; 90.00%, 87.50%, 94.74%, 77.78%and 0.747 for the Bioperfectus kit, and 82.50%, 81.25%, 91.67%, 65.00%and 0.593 for the BGI kit, respectively. The positive, negative and total coincident rates and kappa value of viral nucleic acid detection results using the samples extracted by one-step cleavage and magnetic bead methods were 95.24%, 100.00%, 96.43%and 0.909, respectively, but the one-step cleavage method took only 25 min, while the magnetic bead method required 180 min. The positive, negative and total coincident rates and kappa value of viral nucleic acid detection results using the samples extracted by the two different nucleic acid extractors were 85.00%, 100.00%, 89.29% and 0.764, respectively. CONCLUSIONS The detection efficacy for SARS-CoV-2 nucleic acid by the Sansure kit is relatively higher and the one-step cleavage method has advantages of convenient operation and less time consuming.
Betacoronavirus ; genetics ; isolation & purification ; Coronavirus Infections ; diagnosis ; virology ; Humans ; Pandemics ; Pneumonia, Viral ; diagnosis ; virology ; RNA, Viral ; genetics ; isolation & purification ; Reagent Kits, Diagnostic ; standards

Objective:To compare the clinical effects of Zero-profile (Zero-p) intervertebral fusion and titanium plate combined with cage fusion in treating symptomatic adjacent segment disease (ASD) after anterior cervical discectomy and fusion (ACDF).Methods:Retrospective analysis was performed on 26 patients who underwent ACDF and readmission due to concurrent symptomatic ASD from October 2014 to June 2019. There were 17 males and 9 females, aged 54.15±8.60 (range 41-68) years. The index level included C 2, 3 1 case, C 3, 4 3 cases, C 4,5 9 cases, C 5, 6 6 cases, C 6, 7 7 cases. Twelve cases underwent anterior cervical decompression with Zero-p intervertebral fusion and fixation (Zero-p group), while 14 cases underwent anterior cervical decompression with titanium plate combined with cage fusion and fixation (titanium plate group). The following parameters, including operative duration, intraoperative blood loss, Japanese Orthopaedic Association (JOA) score, visual analogue score (VAS), neck disability index (NDI), dysphagia Bazaz grade, bone graft fusion Eck grade, C 2-C 7 Cobb angle, and related complications, were compared between the two groups. Results:The operation was performed successfully in all the patients. The patients were followed up for averagely 33.38±21.26 (range 12-71) months. The operation duration was 95.83±5.47 (range 89-105) min in the Zero-p group, which was shorter than 121.28±8.24 (range 106-131) min in the titanium plate group. The Bazaz classification of dysphagia in the Zero-p group was superior to the titanium plate group at 1 month after operation ( W=126.00, P=0.022). Neither group had dysphagia 3 months after surgery. The JOA score increased from preoperative 9.50±1.31 to 14.33±0.78, and VAS decreased from 5.33±1.67 to 0.83±0.72 in the Zero-p group. The NDI decreased from 43.62%±9.31% to 14.99%±3.26%, and C 2-C 7 Cobb changed from 8.26°±2.92° to 14.80°±4.18° in the Zero-p group. The JOA score increased from preoperative 9.14±1.79 to 14.71±0.73, and VAS decreased from 5.43±1.55 to 1.43±0.76 in the titanium plate group. The NDI decreased from 43.76%±8.47% to 14.22%±4.59%, and C 2-C 7 Cobb changed from 5.53°±9.04° to 14.68°±6.89° in the titanium plate group. No complication, such as screw loosening or breakage or esophageal injury, occurred during the follow-up. Conclusion:Both methods can achieve good clinical effects in treating symptomatic ASD and can restore the physiological curvature of the cervical spine to a certain extent. Furthermore, the advantages of Zero-p intervertebral fusion include shorter operation duration, reducing soft tissue injury and less postoperative dysphagia.

Objective: To explore the effects of shear stress on morphology, adhesion and proliferation of human umbilical cord blood mesenchymal stem cells(hUC-MSCs). Methods: The hUC-MSCs were cultured in vitro until confluence and then placed in a flow system.The cells were subjected to different shear stress (1, 2, 3, 4 dye/cm²) for 2 hours and 6 hours, and no shear stress treatment cells served as a static control.The morphological changes of hUC-MSCs in different groups were analyzed by phase contrast microscopy and immunofluorescence.The mRNA expression levels of intercellular adhesion molecule-1 (ICAM-1) and Ki67 were detected by real-time PCR. Results: Compared with the static control group, the hUC-MSCs cells were arranged in the direction of fluid after treated with shear stress.The immunofluorescence results showed that the cytoskeletal protein F-actin filaments was prolonged after shear stress.The cytoskeleton was further elongated in the 2 dye/cm² for 6 hours group when compared with 2 dye/cm² for 2 hours group, and the cytoskeleton was loosened when time extended to 6 hours.Real-time PCR results showed that the relative expressions of ICAM-1 mRNA and Ki67 mRNA in the static control group and different gradient shear stress groups were significantly different, with significant differences among them (F=17.141, P=0.000; F=11.336, P=0.001). The relative expression of ICAM-1 mRNA in the 1, 2, 3, 4 dye/cm² shear stress group was 2.74±0.32, 9.77±1.19, 6.70±0.92 and 5.69±0.72, respectively, which was significantly higher than 1.00±0.28 in the static control group, with significant differences between them (all at P<0.05). The relative expression of Ki67 mRNA in the 3 dye/cm² and 4 dye/cm² shear stress group was 0.39±0.09 and 0.04±0.02, respectively, which was significantly lower than 1.00±0.24 in the static control group, with statistically significant differences between them (both at P<0.05). Conclusions After treated with fluid shear stress, hUC-MSCs are arranged in the direction of fluid.Shear stress can promote the adhesion of hUC-MSCs.As the increase of shear stress intensity, cell proliferation is inhibited.

Objective: To observe the effects of He-Ne laser on the expression of extracellular matrix and its regulatory factors in degenerated temporomandibular joint(TMJ) of rabbits. Methods: 40 New Zealand adult white rabbits were randomly divided into normal group,sham model group,TMJOA model group and laser treatment group(n = 10),the rats in treatment group were treated by He-Ne laser irradination at acupoints. The rats in each group were divided into 1 d and 11 d groups(n = 5). The animals were respectively killed 1 d and 11 d after operation and HE staining was used to observe the histomorpholy. The protein expression of extracellular matrix and its regulatory factors were examined by Western blot. Results: After He-Ne laser treatment,the fiber layer of condylar cartilage was slightly loose,part of the fiber was newly produced. The level of Col-2,PRG-4,TIMP-1,BMP-2 was up-regulated and the of MMP-13 was down-regulated in the 11 d treatment group. Conclusion: He-Ne laser irradiation on acupoints may up-regulate the expression of extracellular matrix (Col-2 and PRG-4) and its regulatory factors (TIMP-1 and BMP-2),down-regulate the expression of MMP-13.