Objective: To explore the potential category patterns of risk prevention and control behaviors of HIV infection among young students who have sex with men (MSM) and their impact on HIV infection and late detection, aiming to optimize intervention strategies. Methods: From September 2017 to December 2024, a total of 1 637 MSM young students in Tianjin were recruited through both online and offline channels. Latent class analysis was applied to classify 11 HIV risk prevention and control behaviors [condom use during the most recent anal sex in the past 6 months, consistent condom use, use of water based lubricants, abstinence from recreational drugs, regular on site professional testing, fixed sexual partners, partner testing, awareness of partner s HIV testing results, testing before sexual activity, nucleic acid testing, and use of pre exposure prophylaxis (PrEP) or post exposure prophylaxis (PEP)]. Multivariate Logistic regression analyzed associations between demographic characteristics/intervention services factors and latent classes. Differences in HIV infection and late detection across behavior patterns were compared. Results: HIV risk prevention and control behaviors among MSM students were classified into three latent classes:condom dependent group (38.42%), low prevention group (27.73%), and comprehensive prevention group (33.85%). Students who received condom promotion/testing services were more likely to belong to the comprehensive prevention group ( OR =5.58), while those who received peer education were less likely to the comprehensive prevention group ( OR =0.43) (both P <0.01). Among the MSM student population, the HIV infection rate was 4.83%, with 2.26% of cases detected late. The HIV infection rate (1.45%) and late detection proportion (0.82%) in the comprehensive prevention group were lower than those in the low prevention group (7.89% and 3.83%, respectively) ( χ 2=16.20, 7.31, both P <0.01). Conclusions HIV risk prevention and control behaviors among MSM young students exhibit significant heterogeneity. Comprehensive prevention strategies can effectively reduce HIV infection and late detection risks. It is necessary to optimize peer education content and improve the accessibility of diversified prevention measures such as PrEP/PEP to enhance HIV prevention and control.

Objective To investigate the correlation between serum remnant cholesterol(RC)levels and the occurrence of arteriosclerosis obliterans(ASO)of the lower extremity in patients with type 2 diabetes mellitus(T2DM).Methods 355 cases of T2DM patients hospitalized in the department of endocrinology of Tianjin Hospital affiliated with Tianjin University from January 2018 to December 2022 were selected and di-vided into the non-ASO group(180 cases)and the ASO group(175 cases)according to whether the patients were combined with ASO or not.General clinical and laboratory data of patients were collected and RC levels were calculated;Spearman rank correlation analysis was performed to evaluate the correlation between RC lev-els and metabolic indices,and multivariate logistic regression analysis was conducted to assess the association between serum RC levels and the risk of ASO in T2DM patients.Results Compared with the non-ASO group,the ASO group had older age,the course of diabetes was longer,the incidence rates of diabetic peripher-al neuropathy,diabetic nephropathy,coronary heart disease,hypertension,and cerebral infarction were higher,statin use was more frequent,the levels of systolic blood pressure(SBP),triglyceride(TG),creatinine(Cr),uric acid(UA),and RC were higher,and the level of high-density lipoprotein cholesterol(HDL-C)was lower,all differences were statistically significant(P＜0.05).Spearman rank correlation analysis showed that serum RC levels were positively correlated with TG,total cholesterol(TC),and UA(r=0.628,0.289,0.192,P＜0.001),and negatively correlated with HDL-C(r=-0.202,P＜0.001).Multivariate logistic regression anal-ysis revealed that age(OR=1.095,95％CI:1.066-1.124,P＜0.001),diabetic peripheral neuropathy(OR=1.877,95％CI:1.114-3.162,P=0.018),diabetic nephropathy(OR=2.149,95％CI:1.272-3.629,P=0.004),systolic blood pressure(OR=1.017,95％CI:1.004-1.031,P=0.012),and RC(OR=2.644,95％CI:1.569-4.453,P＜0.001)were independent influencing factors for ASO in T2DM patients.Conclusion Elevated serum RC levels are closely associated with ASO in T2DM patients.

Objective To evaluate the feasibility of imaging the rat cardiac conduction system (CCS) using transaortic antegrade perfusion of Alexa Fluor 633-labeled antibodies targeting hyperpolarization-activated cyclic nucleotide-gated cation channel 4 (HCN4) and connexin (Cx). The study also sought to optimize antibody dosage, perfusion duration, and assess the photostability of the dye. Methods Ex vivo rat heart model with transaortic antegrade perfusion was established using 33 male SPF-grade Sprague-Dawley (SD) rats. Primary and secondary antibody solutions were sequentially perfused in an antegrade manner. After perfusion for predetermined durations, the atrioventricular junction was observed, and the fluorescence intensity of the corresponding area was recorded. Five dose-gradient groups (n=3 rats/group), five perfusion time-gradient groups (n=3 rats/group), and ten continuous LED light exposure time-gradient groups (using 3 rats prepared with a fixed dose and time) were established to observe and record regional fluorescence intensity. Standard immunofluorescence staining was performed on both paraffin and frozen sections for comparative histological analysis. Results A region of aggregated red fluorescent signal was observed in the atrioventricular junction. Following semi-quantitative fluorescence intensity analysis of HCN4/Cx43 and validation through comparative histology, this structure was identified as the atrioventricular node (AVN) region. The AVN-to-background fluorescence intensity ratio showed no statistically significant differences among groups with increasing antibody dosage (P>0.05). The ratio increased with longer antibody perfusion times. Furthermore, no statistically significant differences in the ratio were observed among groups with extended light exposure (P>0.05). Conclusion Transaortic antegrade perfusion of fluorescently labeled antibodies can successfully image the AVN within the CCS of ex vivo rat hearts. Increasing the antibody dosage does not significantly improve the AVN imaging effect. Longer antibody perfusion time results in better imaging quality of the AVN. The fluorescent dye maintains sufficient visualization of the AVN even after prolonged (8 h) exposure to light.

Objective: To analyze the use of preexposure prophylaxis (PrEP) among male students who had sex with men (MSM) with different sexual behavior patterns using potential categories, so as to provide evidence for determining the use patterns of PrEP consistent with MSM. Methods: A questionnaire survey was conducted by proportional sampling method on MSM in 31 provincial administrative regions in mainland China from 20 October to 30 December 2021, a total of 1 040 students were selected for the study. Latent variable analyses were conducted on a total of seven sexual behavioral characteristics, including knowledge of sexual partner HIV infection, frequency of condom use, number of sexual partners, engaging in group sex, provision of commercial sex, use of sex aids, and history of sexually transmitted infections (STIs) in the past year. And demographic characteristics were analyzed by Logistic regression analysis. The rates of PrEP awareness, willingness to use and usage rate in different sexual behavior risk groups were investigated. Results: Student MSM could be divided into two potential category groups:a lowrisk behavior group (82.4%) and a highrisk behavior group (17.6%). The PrEP usage rate (15.8%) was higher in the highrisk behavior group, and the difference was statistically significant compared to the lowrisk behavior group (7.2%) (χ2=13.43, P<0.05). Student MSM residing in the northeast, south, and northwest of China, in the pilot city, and with a sex role of "0.5" (possible acceptance and insertion of sexual behavior) were more likely to be in the highrisk behavior group (OR=3.13, 3.07, 3.87, 2.22, 1.66, P<0.05). Conclusion Student MSM in highrisk and lowrisk sexual differs in the behavior of PrEP, and targeted interventions should be implemented to promote the use of PrEP and reduce HIV infection in this population.

Objective: To investigate the current situation and related factors of antiretroviral therapy (ART) among HIV infected male students engaging in men who have sex with men (MSM), so as to provide the reference data for HIV prevention and treatment. Methods: In November 2021, 137 MSM students from 31 provincial administrative regions in China were recruited. An online survey was conducted to collect data on demographic characteristics, ART status, CD4 count, and HIV viral load before treatment. Logistic regression was used to analyze the factors related the effectiveness of ART in MSM. Results: Among the included research subjects, 14.6% had late detection of HIV,97.1% of participants were currently undergoing ART. Among those whose ART duration was less than 6 months, while 76.9% were undergoing ART. Logistic regression indicated that HIV infected students who received ART for more than 24 months ( OR =5.28, 95% CI =1.38-20.22) had a higher rate of successful HIV suppression. HIV infected students who reported physical sensory side effects ( OR =0.08, 95% CI =0.01-0.71) and cognitive side effects ( OR =0.28, 95% CI =0.09-0.90) were more likely to experience failure of ARI inhibition ( P <0.05). Conclusions There is still room for improvement in the efficacy of ART among MSM students. Strategies to improve treatment adherence must consider individual variances among HIV infected patients and the side effects of medications when designing treatment plans.

The cardiac conduction system (CCS) is a set of specialized myocardial pathways that spontaneously generate and conduct impulses transmitting throughout the heart, and causing the coordinated contractions of all parts of the heart. A comprehensive understanding of the anatomical characteristics of the CCS in the heart is the basis of studying cardiac electrophysiology and treating conduction-related diseases. It is also the key of avoiding damage to the CCS during open heart surgery. How to identify and locate the CCS has always been a hot topic in researches. Here, we review the histological imaging methods of the CCS and the specific molecular markers, as well as the exploration for localization and visualization of the CCS. We especially put emphasis on the clinical application prospects and the future development directions of non-destructive imaging technology and real-time localization methods of the CCS that have emerged in recent years.

Objective: To explore the pre-exposure prophylaxis (PrEP) awareness, willingness, uptake patterns, barriers and needs among Chinese student men who have sex with men (MSM), so as to provide relevant evidence for targeted interventions with PrEP. Methods: A proportional sampling method was used to conduct a cross sectional survey of MSM aged 16 years and older residing in 21 provinces, municipalities, and autonomous regions in mainland China between October 20 and December 20, 2021, to collect information on demographic and sexual behavioral characteristics, and 923 students of them were selected as the subjects of this study. The chi-square test and Fisher s test were used for univariate analysis, followed by multivariate Logistic regression to analyze the influencing factors of PrEP awareness and uptake. Results: According to the cascade analysis method, the awareness, willingness, uptake and adherence rates of PrEP among the student MSM were obtained as 88.95%, 67.36%, 13.20% and 45.21 %, respectively. HIV testing more than once in the last 3 months, and all of them were aware of the HIV test results of their sexual partners, and those with high frequency of condom use had a higher rate of awareness ( OR =2.32, 1.79, 1.69, P <0.05). Willingness rates were higher for those from the pilot city, using substances, and HIV testing more than once in the last 3 months ( OR =2.13, 1.65, 1.69, P <0.05). Higher rates of uptake were found among those from high risk and pilot areas, presence of commercial sex, substance use, and high literacy ( OR =5.60, 3.54,2.81, 1.92, 4.54, P <0.05). Adherence rates were higher among those who used one pill per day or both ( OR =12.77, 13.26, P <0.05). The barriers and needs faced by student MSM were primarily personal concerns about medication side effects, preventative effects, and confidence in sexual behavioral styles, and the high cost of medication and related service costs. Conclusions The student MSM population in China is characterized by high awareness, low willingness, low uptake, and low adherence to PrEP. Targeted interventions should be considered and tailored by the departments to facilitate PrEP promotion among student MSM.

Abstract OBJECTIVE To establish an efficient and simple HPLC-MS/MS method for determination of flucloxacillin in newborn plasma, and to investigate the interaction between ambroxol and flucloxacillin in newborns. METHODS The samples were analyzed by API4000 HPLC-MS/MS. Ultimate XB-C18 column(2.1 mm×100 mm, 5 μm) were carried out. The mobile phase was composed of water-0.1% formic acid(A) and acetonitrile-0.1% formic acid(B). The quantitative analysis of the ion transitions were monitored at m/z 452.6→284.2 for flucloxacillin and m/z 821.4→397.3 for rifampicin(internal standard). RESULTS The linear range of flucloxacillin under this analysis method was 0.20-80 ng·mL-1, and the lower limit of quantification was 0.20 ng·mL-1; The intra-day and inter-day precision of flucloxacillin were both less than 8.23%; The extraction recovery was in the range of 85.3%-89.2%, and the matrix effect was between 89.3%-92.3%; The stability of plasma samples was good under conditions of 12 h at room temperature, 4 h at room temperature after treatment, repeated freeze-thaw for 3 times, and -20 ℃ freezing for 30 d. The results of clinical samples indicated that the combination of ambroxol could significantly increase the blood concentration of flucloxacillin. CONCLUSION The established HPLC-MS/MS method is accurate, sensitive and can be used for the determination of flucloxacillin concentration in neonatal plasma. The results of clinical samples indicate that ambroxol can significantly increase the blood concentration of flucloxacillin. There are drug interactions between ambroxol and flucloxacillin.

Polyetheretherketone (PEEK) as a new type of thermoplastic engineering plastic, has good biological activity, elastic modulus close to human cortical bone and radiation permeability, and has been widely used in medical field. This study aims to explore the safety and clinical efficacy of using 3D printing personalized PEEK materials to repaire scapular bone defects after bone tumor resection. A total of 6 patients who underwent the implantation of 3D printed PEEK scapular prosthesis from January 2020 to December 2021 in Yunnan Cancer Hospital were retrospectively analyzed. There were 3 males and 3 females, with age ranged from 14 to 52 years. There were 1 case of synovial sarcoma, 1 of Ewing's sarcoma, and 4 of chondrosarcoma. PEEK prosthesis was designed and fabricated based on CT data before surgery. Tumor resection and prosthesis replacement were performed under the premise of ensuring safe surgical boundaries, including 2 cases of total scapular prosthesis replacement and 4 cases of partial scapular prosthesis replacement. The operation time was 90-170 min, and the intraoperative blood loss was 100-400 ml. All 6 patients received satisfactory follow-up, with a tumor progression free survival time of 16-28 months. No tumor recurrence or metastasis was observed, and all patients survived tumor free. At last follow-up, the Constant-Murley shoulder joint score was a minimum of 62 points and a maximum of 68 points. The Japanese Orthopaedic Association's shoulder joint score was 63 points minimum and 78 points maximum. Computer-aided design 3D printing PEEK material prosthesis has certain advantages in the treatment of scapular tumor limb salvage. It has light weight, well adapted, relatively simple installation, good histocompatibility, and can obtain a better appearance and function of the shoulder joint after operation. It can become one of the options for limb salvage treatment of scapular tumor.

Objective: To understand the basic characteristics, sexual behavior and the use of recreational new drugs of young men who have sex with men (MSM) in Tianjin, and to explore the characteristics of young MSM who use recreational drugs, so as to provide reference for the policy making of HIV/AIDS prevention and control in universities. Methods: From January 1, 2018, solstice to December 31, 2018, participants were recruited in the bathrooms, bars and social network sites in Tianjin by snowball sampling. The basic demographic information, sexual behavior and recreational drug use of the participants were collected through face to face interviews and questionnaires. Logistic regression was used to analyzed the characteristic differences drug users and non users among young MSM. Results: A total of 826 young MSM were included in the study, 32 were infected with HIV, and the overall prevalence rate was 3.87 %. Totally 371 (44.92%) were drug users. Rush Poppers were the most common used drug ( 98.65 %). Of the young MSM using new drugs, 306 (82.48%) multiple drugs were used, 65 people ( 17.52 %) only one drug has been used. Among new drug users, multiple drug users had higher HIV prevalence rate (16.92%) than single drug users (4.57%). There were statistically significant differences between drug users and non users in age, age of first sexual behavior, household registration, sexual orientation, education level, sexual partners seeking routes, unprotected anal intercourse and HIV testing history( OR=3.70，5.51，0.51，0.60，4.64，0.40，0.52，1.98，2.29，P <0.05). Conclusion The utilization rate of recreational drugs among young MSM in Tianjin was high. Relevant departments should strengthen the propaganda of recreational drugs and HIV prevention among college students, improve the sexual health awareness of young MSM, and establish a long term HIV and recreational drug prevention system.