OBJECTIVE: To estimate the primary electron beam parameters (PEB), including energy, radial intensity distribution and average angular divergence, of the individual linear accelerator using the Monte Carlo method. METHODS: A model of the treatment head and a standard field were built by BEAMnrc, and the dose distribution was simulated in water phantoms by DOSXYZnrc to obtain the percentage depth dose curve and off-axis ratio. By debugging the parameters mentioned above until the simulation and measurement results could match. RESULTS: The simulation and measurement results could achieve the best match when the parameters mentioned above were 6.25 MeV, 0.95 mm and 0.1° respectively. CONCLUSION The PEB of a linear accelerator could have a significant impact on the output beam characteristics. Monte Carlo estimation is one of the most crucial steps in establishing an individual linear accelerator model.
Monte Carlo Method ; Particle Accelerators ; Electrons ; Radiotherapy Dosage ; Phantoms, Imaging

Objective: To analyze changes in Rh system antibodies among antibody-positive patients and evaluate the efficacy of Rh phenotype-matched electronic cross-matching (hereinafter referred to as Rh-ECM). Methods: A retrospective analysis was performed on antibody screening data of 48 254 patients in our hospital from December 2023 to March 2025. The antibody screening results were compared between the pre-application phase (n=46 346, control group) and post-application phase (n=48 254, experimental group) of Rh-ECM technology, focusing on the changes in the proportion of Rh system antibodies, with statistical analysis conducted using SPSS 26.0 software. Meanwhile, the initial and re-examination situations of Rh antibody in the antibody screening of approximately 20 000 person-times each before (June 2019 to June 2020, n=21 048) and after (July 2020 to April 2021, n=20 965) of Rh-ECM were evaluated to explore the influence of Rh-ECM on the detection rate of Rh antibody. Results: After Rh-ECM implementation, 345 positive cases (0.7%) (345/48 254) were detected among 48 254 patients, primarily consisting of mns system antibodies (128 cases, 37.1%) (128/345) and rh system antibodies (95 cases, 27.5%) (95/345). Before Rh-ECM implementation, 199 positive cases (0.4%) (199/46 346) were detected among 46 346 patients, with rh system antibodies accounting for 97 cases (48.7%) (97/199). The difference in the composition ratio of Rh antibodies between the two phases was statistically significant (P<0.001), and the relative risk ratio of Rh antibody detection after Rh-ECM implementation was 56.5% compared to before. Another set of data analysis showed that before Rh-ECM, there were 37 cases with initial positive results and 8 cases with re-examination positive results; after Rh-ECM, these numbers were 44 and 2 respectively There was a statistically significant difference in the re-examination positive rate of Rh antibodies between the two stages (P<0.05). Conclusion: The implementation of Rh-ECM technology significantly reduced the proportion of Rh system antibodies among patients with positive antibody screening results. This suggests that Rh-ECM can effectively reduce the detection rate of Rh antibodies, which may be related to the reduced risk of antibody production due to Rh-matched transfusion, thus improving transfusion safety. Therefore, Rh-ECM is worthy of broader promotion in clinical transfusion testing.

Objective To analyze the effects of deep learning image reconstruction(DLIR)and adaptive statistical iterative recon-struction V(ASIR-V)on the imaging quality of chest CT in patient with pulmonary nodules,and to evaluate the differences based on different image reconstruction techniques in the detection of efficiency of computer-aided diagnosis(CAD)for pulmonary nodules.Methods The image data of pulmonary nodules of eighty patients with chest CT screening were reconstructed with ASIR-V 80％,DLIR-low(DLIR-L),DLIR-medium(DLIR-M)and DLIR-high(DLIR-H)images,respectively.The objective image quality and sub-jective image quality of the four groups were compared and analyzed.Objective image quality includes CT value of region of interest(ROI),noise,signal-to-noise ratio(SNR),contrast-to-noise ratio(CNR)and image average gradient.The diagnostic efficacy of CAD in detecting pulmonary nodules of reconstructed images among four groups were further evaluated.Results There were no signifi-cant difference in CT value of ROI of reconstructed images among the four groups(P＞0.05).The noise,SNR and CNR of DLIR-H images were similar to those of ASIR-V 80％(P＞0.05),but significantly better than those of DLIR-L and DLIR-M(P＜0.05).The average gradient of DLIR-L,DLIR-M and DLIR-H images were significantly higher than those of ASIR-V 80％(P＜0.05).The subjective image quality scores of DLIR-L,DLIR-M and DLIR-H images were significantly higher than those of ASIR-V 80％(P＜0.05),and the subjective image quality score of DLIR-H image was the highest.CAD showed the highest true positive rate in DLIR-H images for detecting pulmonary nodules(P＜0.05),and CAD showed the highest false positives per capita in ASIR-V 80％images for detecting pulmonary nodules(P＜0.05).Conclusion The noise,SNR and CNR of DLIR-H images are similar to those of ASIR-V 80％,with the significantly higher image clarity and subjective image quality scores.DLIR-H has advantages in CAD detection of pulmonary nodules,which is an ideal image reconstruction technology for chest CT pulmonary nodule screening.

[Objective]To investigate primary and secondary transfer of exfoliated cells from human hands on non-porous substrates such as plastic steering wheel or computer mouse.[Methods]DNA detection sensitivity and detection limit for mixed DNA profiling were examined to understand our laboratory's ability to test for trace DNA.Forensic swabs were used to collect samples from volunteers'one-hour-long unwashed hands,substrates touched by volunteers'immediately or 30 min following shaking hands,and individual A's daily-use substrates touched by individual B and then by individual A again.Simulations were conducted to assess the potential for introduction of another person's exfoliated cells from hands into routine casework samples.[Results]Our laboratory can obtain a full DNA profile from as little as 0.020 ng of DNA and detect minor components in a 1:9 mixed DNA sample.85%of samples from unwashed hands yielded a full DNA profile.Primary transfer of a full DNA profile was found in 77%of substrates touched by volunteers'dominant hand 30 min after hand washing,allowing differentiation between good and poor shedders,with no significant difference in genders and substrate types.75%of substrates touched 30 min after hand washing and then immediately following handshaking yielded the other individual's DNA profile(secondary transfer),with the number of short tandem repeat(STR)loci detected ranging from 0 to 23;the percentage and number decreased substantially when the substrates were touched 30 minutes later.No foreign DNA was detected in routine casework samples with introduced exfoliated cells from hands.When two individuals took turns touching items with their hands,the major contributor to the DNA profile was not always the individual who made the last contact.[Conclusions]Primary and secondary DNA transfer can be detected on non-porous substrates,and based on the deposit of hand exfoliated cells,individuals can be categorized as good or poor shedders,which is an important factor affecting detection of DNA transfer.Besides considering the laboratory's DNA detection sensitivity,if DNA is detected on substrates by hand contact,we need to take into account the potential for secondary transfer at different levels of activity when interpreting the results.

Pulmonary sarcomatoid carcinoma(PSC)is a rare and highly malignant tumor,which includes the follow-ing five pathologic types:pleomorphic carcinoma,spindle cell carcinoma,giant cell carcinoma,carcinosarcoma and pulmonary blastoma.The onset of PSC is occult with non-specific clinical symptoms and signs.The clinical manifestations include irritat-ing cough,bloody sputum,dyspnea,chest pain and so on,which are closely related to the growth and invasion site of the tumor.PSC tends to metastasize early,so most patients are already in local advanced stage or advanced stage with a median survival of 9 months at the time of hospital visit.A patient with primary PSC which led to 90%stenosis in central airway was treated by com-bined method of vascular and tracheoscopic intervention in our respiratory center.This treatment prolonged the patient's survival time and got a satisfactory effect at 19-month follow-up after surgery.Herein we report the case for clinical reference.

Background and objective As a new technique developed in recent years,bronchoscopic interven-tion therapy has the advantages of minimal invasion,high safety and repeatability.The aim of this study is to investigate the clinical characteristics of bronchopleural fistula(BPF)induced by surgeries for lung malignancies or benign diseases and the effect of bronchoscopic intervention therapy for BPF,so as to provide support for prevention and treatment of BPF.Methods Data 64 patients with BPF who were treated by bronchoscopic intervention in Respiratory Disease Cen-ter of Dongzhimen Hospital,Beijing University of Chinese Medicine from June 2020 to September 2023 were collected.Patients with fistula diameter ≤5 mm were underwent submucous injection of macrogol,combined with blocking therapy with N-butyl cyanoacrylate,medical bioprotein glue or silicone prosthesis.Patients with fistula diameter＞5 mm were im-planted with different stents and cardiac occluders.Locations and characteristics of fistulas were summarized,meanwhile,data including Karnofsky performance status(KPS),shortbreath scale(SS),body temperature,pleural drainage volume and white blood cell count before and after operation were observed.Results For all 64 patients,96 anatomic lung resections in-cluding pneumonectomy,lobectomy and segmentectomy were executed and 74 fistulas occurred in 65 fistula locations.The proportion of fistula in the right lung(63.5％)was significantly higher than that in the left(36.5％).Besides,the right inferior lobar bronchial fistula was the most common(40.5％).After operation,KPS was significantly increased,while SS,body tem-perature,pleural drainage volume and white blood cell count were significantly decreased compared to the preoperative values(P＜0.05).By telephone follow-up or readmission during 1 month to 38 months after treament,median survival time was 21 months.33 patients(51.6％)showed complete response,7 patients(10.9％)showed complete clinical response,18 patients(28.1％)showed partial response,and 6 patients(9.4％)showed no response.As a whole,the total effective rate of broncho-scopic intervention for BPF was 90.6％.Conclusion BPF induced by pulmonary surgery can lead to severe symptoms and it is usually life-threating.Bronchoscopic intervention therapy is one of the fast and effective therapeutic methods for BPF.

Objective: This study aimed to determine the predictive performance of non-contrast CT (NCCT) signs for hemorrhagic growth after intracerebral hemorrhage (ICH) when stratified by onset-to-imaging time (OIT). Materials and Methods: 1488 supratentorial ICH within 6 h of onset were consecutively recruited from six centers between January 2018 and August 2022. NCCT signs were classified according to density (hypodensities, swirl sign, black hole sign, blend sign, fluid level, and heterogeneous density) and shape (island sign, satellite sign, and irregular shape) features. Multivariable logistic regression was used to evaluate the association between NCCT signs and three types of hemorrhagic growth: hematoma expansion (HE), intraventricular hemorrhage growth (IVHG), and revised HE (RHE). The performance of the NCCT signs was evaluated using the positive predictive value (PPV) stratified by OIT. Results: Multivariable analysis showed that hypodensities were an independent predictor of HE (adjusted odds ratio [95% confidence interval] of 7.99 [4.87–13.40]), IVHG (3.64 [2.15–6.24]), and RHE (7.90 [4.93–12.90]). Similarly, OIT (for a 1-h increase) was an independent inverse predictor of HE (0.59 [0.52–0.66]), IVHG (0.72 [0.64–0.81]), and RHE (0.61 [0.54– 0.67]). Blend and island signs were independently associated with HE and RHE (10.60 [7.36–15.30] and 10.10 [7.10–14.60], respectively, for the blend sign and 2.75 [1.64–4.67] and 2.62 [1.60–4.30], respectively, for the island sign). Hypodensities demonstrated low PPVs of 0.41 (110/269) or lower for IVHG when stratified by OIT. When OIT was ≤ 2 h, the PPVs of hypodensities, blend sign, and island sign for RHE were 0.80 (215/269), 0.90 (142/157), and 0.83 (103/124), respectively. Conclusion Hypodensities, blend sign, and island sign were the best NCCT predictors of RHE when OIT was ≤ 2 h. NCCT signs may assist in earlier recognition of the risk of hemorrhagic growth and guide early intervention to prevent neurological deterioration resulting from hemorrhagic growth.

Abstract: Objective　To investigate the antimicrobial activity of omadacycline (OMC) against clinical Streptococcus agalactiae (GBS) isolates, as well as its relationship with biofilm formation, resistance genes and virulence genes. Methods　A total of 136 strains of Streptococcus agalactiae isolated from Shenzhen Nanshan People's Hospital between 2015 to 2020. The minimum inhibitory concentration (MIC) of OMC against Streptococcus agalactiae was determined by broth microdilution. Crystal violet staining was used to detect the biofilm formation ability of GBS. Resistance genes (tetM, tetO, tetK, ermB, OptrA) and virulence genes (cpsⅢ, bca, fbsA, cpsA, scpB) were investigated by polymerase chain reaction (PCR). Results　Among the 136 clinical isolates of GBS, 20 strains (14.7%) were resistant to OMC, 64 (47.1%) were intermediate, and 52 (38.2%) were sensitive. Fifty-seven strains (41.9%) were biofilm-positive, 20 of which (35.1%) were sensitive to OMC. Seventy-nine strains (58.1%) were biofilm-negative, 32 of which (40.5%) were susceptible to OMC. There was a statistically significant difference in the sensitivity rates between the two groups of strains (χ2=63.062, P<0.001), but there was no significant difference in the sensitivity of OMC among the biofilm-positive strains (Fisher's exact test, P=0.824). The resistance rates of tetM, tetO, ermB and OptrA positive strains were higher than those of negative strains, while tetK was opposite. The presence of tetM (Z=0.815, P=0.415), tetO (Z=0.151, P=0.88), tetK (Z=0.567, P=0.571), ermB (Z=1.198, P=0.231) resistance genes in Streptococcus agalactiae had no significant impact on the sensitivity of OMC. However, the presence of the OptrA resistance gene showed a statistically significant effect on the sensitivity of OMC (Z=2.913, P=0.004). The virulence factors cpsⅢ, bca, fbsA, cpsA and scpB were all detected at a rate higher than 50%. The presence of the virulence genes cpsⅢ (Z=0.222, P=0.824), bca (Z=0.141, P=0.888), fbsA (Z=0.813, P=0.416), and cpsA (Z=1.615, P=0.106) in Streptococcus agalactiae had no significant impact on the sensitivity of OMC. However, there was a significant inter-group difference in the scpB virulence gene (Z=2.844, P=0.004), but the rank mean values and resistance rates of scpB-positive strains were lower than those of the negative strains. Conclusions　The formation of biofilm in Streptococcus agalactiae reduces its sensitivity to OMC, but there was no significant difference in the sensitivity to OMC among the biofilm-positive strains. The presence of resistance genes tetM, tetO, tetK, ermB, and virulence genes cpsⅢ, bca, fbsA, cpsA, scpB in Streptococcus agalactiae is not associated with OMC resistance, but the presence of the resistance gene OptrA is correlated with OMC resistance..

Polymer nanoparticles generally refer to hydrophobic polymers-based nanoparticles, which have been extensively studied in the nanomedicine field due to their good biocompatibility, efficient long-circulation characteristics, and superior metabolic discharge patterns over other nanoparticles. Existing studies have proved that polymer nanoparticles possess unique advantages in the diagnosis and treatment of cardiovascular diseases, and have been transformed from basic researches to clinical applications, especially in the diagnosis and treatment of atherosclerosis (AS). However, the inflammatory reaction induced by polymer nanoparticles would induce the formation of foam cells and autophagy of macrophages. In addition, the variations in the mechanical microenvironment of cardiovascular diseases may cause the enrichment of polymer nanoparticles. These could possibly promote the occurrence and development of AS. Herein, this review summarized the recent application of polymer nanoparticles in the diagnosis and treatment of AS, as well as the relationship between polymer nanoparticles and AS and the associated mechanism, with the aim to facilitate the development of novel nanodrugs for the treatment of AS.
Humans ; Polymers/chemistry* ; Cardiovascular Diseases ; Nanoparticles/chemistry* ; Drug Delivery Systems ; Atherosclerosis/pathology*

Cinnabaris(α-HgS) is a mineral traditional Chinese material medica, as a tranquilizer and sedative, which is widely used in combination with herbs for the treatment of children high fever and convulsion.However, a large amount of mercury in Cinnabaris poses a potential risk to the immature central nervous system of children and probably causes severe memory disorders.Inthisstudy,three groups of juvenile rats were given low, medium, and high doses of Cinnabaris by oral gavage once a day for 14 continuous weeks, respectively.The blood mercury concentrations of the rats at different growth phases were monitored by atomic fluorescence spectrometry.The brain structural and functional changes related to the memory functions were investigated through HE staining and Morris water-maze test. Correlation analysis was conducted to clarify the dose- mercury exposure-toxic effect relationship of Cinnabaris and memory disorders.It was found thatthe blood mercury levels increased in both time- and dose-dependent manner.After the 14-week continuous administration of Cinnabaris, the pathological lesions in hippocampal neurons of rats in the high dose group were observed including pyknosis and disordered cell arrangement.In the Morris water-maze test, compared with the control group, rats in the high dose group exhibited the significantly prolonged latency to find the platform and the target quadrant, and the time spent in the target quadrant was obviously shortened. Thus, the significant correlations were established between Cinnabaris dose and mercury exposure,mercury exposure and memory disorders, respectively. In conclusion, the long-term and overdose administration of Cinnabaris in juvenile rats can increase the in-vivo mercury level, destroy the normal hippocampal morphological structure, and lead to memory disorders. This study provided scientific references for the potential mercury poisoning risks pharmacovigilance of Cinnabaris-containing paediatric formulations.