Objective: To understand the prevalence of HIV testing and related factors among young students who had sex in Guangdong Province, in order to provide evidence for relevant education programs and HIV testing promotion in young students. Methods: From September to December 2022, a convenient sampling method was used to select 48 749 young students from 16 universities and mechanic colleges in 6 cities including Guangzhou, Shantou, Maoming, Huizhou, Dongguan, and Zhongshan in Guangdong Province for online questionnaire survey. A total of 2 971 students who ever had sexual experiences were screened out, and the HIV testing situation and related factors were investigated by using the questionnaire designed by AIDS Prevention and Education Project for College Students of China STD and AIDS Prevention Association.The influencing factors of HIV testing were analyzed using Chi square test and multiple Logistic regression model. Results: Among students who had sexual experiences, 11.92% (354/2 971) were tested for HIV. The results of multivariate Logistic regression analysis showed that among young sexual students, using psychoactive substances during sexual activity in the last 1 year ( OR =7.70), having first sex with the same sex ( OR =3.87), having commercial sex ( OR =2.37), having heard of PEP ( OR =2.20), having a high level of self assessed understanding of HIV testing ( OR =1.73), inconsistent use of condoms ( OR =1.56), being aware of HIV infection ( OR =1.53), being aware of HIV knowledge ( OR =1.51) were more likely to test for HIV, and females ( OR =0.39) were less likely to test for HIV ( P < 0.05). Conclusions The proportion of HIV testing is low among sexually active young students in Guangdong Province. Targeted interventions should be tailored to promote HIV testing coverage.

Objective To evaluate the postoperative survival quality in the patients with heart valve re-placement (HVR) in Three Gorges Reservoir area,and to analyze its main influencing factors.Methods A to-tal of 343 valvular heart disease patients from Three Gorges Reservoir area who received HVR treatment for the first time in this hospital from January 2019 to December 2021 were selected by the convenience sampling method.The general data questionnaire and the MOS 36-item short form health survey (SF-36) were adopted to conduct the survey.The main influencing factors affecting the survival quality were analyzed.Results Af-ter HVR,the physical components summary (PCS) score of SF-36 was 238.0±73.6,and the mental compo-nents summary (MCS) score was 254.8±83.6,and the scores in each dimension were significantly lower than those of the Chinese norm (P<0.05).The multiple stepwise linear regression analysis results showed that the age,gender,place of residence,education level,postoperative time,complications and readmission were the influencing factors of PCS and MCS scores (P<0.05).Conclusion The survival quality of the patients af-ter HVR is different from that of healthy population.The targeted intervention could be carried out according to the influencing factors of the survival quality of the patients,so as to improve their survival quality.

Objective:To explore high-risk sexual behaviors of HIV/AIDS and related factors in young students in Guangzhou.Methods:A cross-sectional survey was conducted in 5 different types of Guangzhou colleges by convenience sampling with minimum number of classes per grade and 600 samples per school from September to November 2021. The R 4.2.2 software was used to consolidate databases. Simultaneously, a logistic regression model and a decision tree algorithm model, stratifying by whether sexual behaviors had occurred before, were constructed. In each layer, the prediction performance of the two models was evaluated through area under receiver operating characteristic and the confusion matrix, and then the model with high prediction performance was retained.Results:A total of 7 346 students were surveyed. The proportion of the respondents reporting sexual experience were 9.08% (667/7 346), in whom 26.24% (175/667) had risky sexual activity in the past year. The decision tree algorithm model performs well in predicting whether high-risk sexual behaviors have occurred in the past year. When the complexity parameter value is 0.018, and nsplit reaches 4, which means there are 5 leaf nodes in the model, the cross error of the tree will be the smallest. The first best grouping variable in the decision tree was whether to use condoms throughout the first sexual behavior. If condoms were used at their sexual debut, but homosexual practices have occurred in the past year, the probability of risky sexual behavior will increase. If homosexual practices have not occurred in the past year, but the age of sexual debut was below 18 years old while the period of HIV education was after high school, the probability of risk sexual behavior will also increase.Conclusions:AIDS-related risky behaviors of young students still deserved attention. The experience of sexual debut and whether AIDS-related health education has been received before the sexual debut were significant predictors for the occurrence of high-risk sexual behavior. The decision tree algorithm model has particular applicability for predicting and screening potential risk populations.

Objective:To investigate the risk perception for risky behavior of HIV/AIDS infection among young students and to analyze the related influencing factors.Methods:A cross-sectional survey was conducted in 5 different types of Guangzhou colleges from September to November 2021, in which convenience sampling and a minimum number of classes per grade and 600 samples per school were used according to the national unity program. Disordered multi-classification logistic regression was used to construct a risk perception model and analyze influencing factors in different risk perception levels.Results:A total of 7 346 young students were surveyed, and most rated themselves at low risk of HIV/AIDS infections (90.58%, 6 654/7 346). A total of 89.10% (6 545/7 346) of subjects' perception of their HIV/AIDS infection risk was consistent with their risk behavior, while 10.90% (801/7 346) was inconsistent. Among those inconsistent subjects, 19.10% (153/801) showed underestimating their risk , while 80.90% (648/801) seen overestimating their risk. Disordered multi-classification logistic regression analysis showed that, after controlling for other factors, compared with the non-sexual group, respondents whose first sex age under 18 had a higher rate of underestimating their risk of infection ( OR=129.39, 95% CI: 73.28-228.48), as well as a higher rate of overestimated their risk of infection ( OR=1.76, 95% CI: 1.04-2.99). First sexual intercourse at age 18 or older was a risk factor for underestimating risk ( OR=70.56, 95% CI: 42.72-116.53), but was not statistically associated with overestimating risk. Being female, other school type, non-heterosexual orientation, and self-rated HIV-related knowledge as fair or no knowledge were risk factors for overestimating risk but were not statistically associated with underestimating risk. Conclusions:Overall, young students in universities of Guangzhou have a good risk perception of HIV/AIDS infection. Individual factors, education factors and sexual experience will influence students' risk perception of HIV/AIDS infection. Raising the awareness rate of HIV/AIDS knowledge and delaying the age of first sexual intercourse will improve the risk perception ability of young students.

Objective:To observe the effect of project-based learning (PBL) in the clinical teaching of radiation physics.Methods:Thirty-two residents specializing in radiotherapy were included in the study. In the experimental group ( n=16), PBL was adopted, while traditional clinical teaching method was employed in the control group ( n=16). After the rotation, the assessment was conducted, as well as a questionnaire survey was performed, including five aspects: overall satisfaction, understanding of radiation physics knowledge, learning motivation, learning burden, and learning efficiency. Results:The assessment score in the experimental group was 86.31±5.41, which was higher than 75.28±5.91 in the control group, and the difference was statistically significant. Residents in the experimental group were satisfied with the effect of PBL.Conclusion:Compared with the traditional teaching method, PBL can improve the learning motivation, efficiency, and performance of radiotherapy residents, which is highly recognized by the residents.

Objective:To design a drum-shaped applicator through Monte Carlo simulation for breast intraoperative radiotherapy.Methods:Applicator designing process is as follows: first, determined the shape of the applicator based on the geometric characteristics of the breast tumor bed closed to the chest wall; second, calculated the scattering angle and dose rate of the electron beam after passing through a series of scattering foils of different thicknesses to determine the thickness of the scattering foil; thrid, modeled the layer according to the applicator′s geometric characteristics where modulator located, and designed the modulator through the relationship between the geometric characteristics of the layer and the surface dose of the applicator. EGSnrc/BEAMnrc and EGS4/DOSXYZ were employed to model the head of the Mobetron, the layer, the applicator, and to calculate the dose distributions.Results:The applicator has two components. The upper component is a 3cm-diametre cylindrical collimator with 0.5cm wall made of 0.3cm steel and 0.2cm water equivalent material (WEM), a 0.13cm-foil made of tansgen. The lower component is a 4cm-diametre drum made of 0.2cm WEM and a 0.14cm maximum thickness hill-shaped modulator made of steel. When the energy of electron beam was 12MeV, the dose rate was about 90.44 cGy/min, and the depth of the 50% isodose curve was 1cm.Conclusion:The applicator is successfully designed, and can obtain a drum-shaped dose distribution.

Objective:To establish an automatic planning method using volumetric-modulated arc therapy (VMAT) for primary liver cancer (PLC) radiotherapy based on predicting the feasibility dose-volume histogram (DVH) and evaluate its performance.Methods:Ten patients with PLC were randomly chosen in this retrospective study. Pinnacle Auto-Planning was used to design the VMAT automatic plan, and the feasibility DVH curve was obtained through the PlanIQ dose prediction, and the initial optimization objectives of the automatic plan were set according to the displayed feasible objectives interval. The plans were accessed according to dosimetric parameters of the planning target volume and organs at risk as well as the monitor units. All patients′ automatic plans were compared with clinically accepted manual plans by using the paired t-test. Results:There was no significant difference of the planning target volume D 2%, D 98%, D mean or homogeneity index between the automatic and manual plans ((58.55±2.81) Gy vs.(57.98±4.17) Gy, (47.15±1.58) Gy vs.(47.82±1.38) Gy, (53.14±0.95) Gy vs.(53.44±1.67) Gy and 1.15±0.05 vs. 1.14±0.07, all P>0.05). The planning target volume conformity index of the manual plan was slightly higher than that of the automatic plan (0.77±0.08 vs. 0.69±0.06, P<0.05). The mean doses of normal liver, V 30Gy, V 20Gy, V 10Gy, V 5Gy and V< 5Gy of the automatic plan were significantly better than those of the manual plan ((26.68±11.13)% vs.(28.00±10.95)%, (29.96±11.50)% vs.(31.89±11.51)%, (34.88±11.51)% vs.(38.66±11.67)%, (45.38±12.40)% vs.(50.74±13.56)%, and (628.52±191.80) cm 3vs.(563.15±188.39) cm 3, all P<0.05). The mean doses of the small intestine, the duodenum, and the heart, as well as lung V 10 of the automatic plan were significantly less than those of the manual plan ((1.83±2.17) Gy vs.(2.37±2.81) Gy, (9.15±9.36) Gy vs.(11.18±10.49) Gy, and (5.44±3.10) Gy vs.(6.25±3.26) Gy, as well as (12.70±7.08)% vs.(14.47±8.11)%, all P<0.05). Monitor units did not significantly differ between two plans ((710.67±163.72) MU vs.(707.53±155.89) MU, P>0.05). Conclusions:The automatic planning method using VMAT for PLC radiotherapy based on predicting the feasibility DVH enhances the quality for PLC plans, especially in terms of normal liver sparing. Besides, it also has advantages for the protection of the intestine, whole lung and heart.

Objective:To investigate the frequency and severity of systemic adverse reactions in children with allergic rhinitis (AR) undergoing subcutaneous immunotherapy (SCIT).Methods:The clinical data of 321 children with allergic rhinitis receiving SCIT at Department of Otorhinolaryngology, Changzhou Third People′s Hospital from January 2016 to January 2020 were retrospectively analyzed. There were 180 boys and 141 girls aged 5 to 14 years. Patients were injected subcutaneously with standardized dust mites allergen extract. The onset time, symptoms and signs and treatment of adverse reactions were documented. The relationship of adverse reactions with gender, age, treatment course and dosage of allergen injection were analyzed.Results:Patients received total 13 053 injections, and 115 adverse reactions (0.88%) occurred in 56 cases (17.45%). The incidence of adverse reactions in children aged 5-9 years was higher than in those aged 10-14 years, for both the number of cases and injections (χ2=4.41, P=0.04; χ2=9.13, P<0.01), but no significant differences were observed in gender of patients. The incidence of adverse reactions in the age group 2-3 years was lower than that in age groups<1 year and 1-<2 years in both of cases and injections (χ2=22.86, P<0.01; χ2=6.43, P=0.01; χ2=12.14, P<0.01; χ2=13.74, P<0.01). The incidence of adverse reactions in the high-dosage phase (100 000 SQ-U) was higher than that in the low-dosage phase (<100 000 SQ-U) (χ2=4.35, P=0.04). Conclusions:The study shows that the incidence of adverse reactions in children with allergic rhinitis receiving subcutaneous immunotherapy is less than 1% in the number of injections and most of them are grade Ⅰ adverse reactions. The study also shows that younger age, the early course of treatment and the high dosage of allergens are risk factors for adverse reactions.

Objective:To explore the application of cannulating the ischemic femoral and right axillary artery in Sun’s procedure for acute type A aortic dissection with lower extremity ischemia.Methods:Twelve patients of acute Stanford type A aortic dissection complicated by lower extremity ischemia were analyzed retrospectively between July 2017 and May 2019, and the right axillary and ischemic femoral artery were used for cardiopulmonary bypass. All the 12 patients were male and categorized as the complicated Stanford type A aortic dissection. The mean age was(48.4±8.4)years, and the median time from symptom onset to emergency operation was 24.00(18.50, 43.25)hours. Eleven patients presented with unilateral extremity ischemia, while bilateral extremity ischemia occurred in one. The prosthetic vessel, with a diameter of 8 mm, was anastomosed to the ischemic femoral artery via an end-to-side way. Both the right axillary artery and the prosthetic vessel were cannulated for CPB. For the proximal dissection in this cohort of patients, we performed Bentall procedure in 5 cases, ascending aortic replacement in 3, and the aortic valve commissure reconstruction with ascending aortic replacement in 4. Total arch replacement with stented elephant trunk implantation were carried out for arch and descending aortic lesion in 12 cases.Results:Early mortality was 8.3%(1/12). The time of CPB, aortic clamp, circulatory arrest, and selective cerebral perfusion averaged(204.6±26.3) min, (114.6±16.6) min, (23.4±8.5) min, and(33.5±11.0) min, respectively. Five patients underwent concomitant bypass procedures, including: ascending aorta-bilateral femoral artery bypass in 1, ascending aorta-right femoral artery bypass in 3, ascending aorta-left femoral artery bypass in 1. Acute renal failure with continuous renal replacement therapy occurred in 4 cases, re-thoratomy for hemaostsis in 1, and re-intubation in 1. One patient developed osteofascial compartment syndrome after aortic repair, and consequent left lower extremity compartment fasciotomy was performed. The mean follow-up time was(17.2±7.6)months, and no aortic-related adverse event was detected during follow up.Conclusion:To acute Stanford type A aortic dissection with lower extremity ischemia, cannulating the ischemic femoral and right axillary artery in Sun’s procedure were associated with lower perioperative mortality and better prognosis.

Objective:To evaluate the application of moderate hypothermia circulatory arrest(MHCA)with a higher temperature(29℃) and bilateral selective antegrade cerebral perfusion(bSACP) in acute Stanford type A aortic dissection(TAAD] treated by total arch replacement with stented elephant trunk implantation.Methods:From July 2019 to January 2020, fifteen patients of acute TAAD undergoing emergent operations via MHCA with a core temperature of 29℃ and bSACP were analyzed retrospectively(modified group), and 26 patients treated by MHCA(25℃) and unilateral selective antegrade cerebral perfusion(uSACP) during the same period were defined as the traditional group. All cases were complicated type A dissection. The mean age in this cohort was 49 years, and 32 patients(78%) were male. Thirty six patients(87.8%) suffered from arterial hypertension. The proximal manipulations included: aortic sinus repair in 13 cases(31.7%), ascending aortic replacement in 29(70.7%), Bentall in 12(29.3%). Total arch replacement with stented elephant trunk implantation was performed in all cases.Results:The in-hospital death occurred in 2(4.9%), and cerebral infarction in 3(7.3%), transient neurologic deficit in 5(12.2%), paraplegia in 2(4.9%). The ratios of above-mentioned adverse events in the traditional and modified group were[2(7.7%) vs. 0, P=0.524], [3(11.5%)vs. 0, P=0.287], [4(15.4%) vs. 1(6.7%), P=0.636], [1(3.8%) vs. 1(6.7%), P=1.000] respectively. The major adverse events in the modified group were transient neurologic deficit and paraplegia in 1 each. Compared with the traditional group, the time of operation, CPB, cardiac arrest, circulatory arrest of the lower part, anterograde low flow cerebral perfusion, mechanical ventilation and ICU stay was shorter. The drainage of 48 hours after surgery was less also. The differences in new acute renal failure requiring CRRT and re-sternotomy for bleeding between groups were not statistical significance. Conclusion:The early results of MHCA(29℃) and bSACP applied in total arch replacement with stented elephant trunk implantation for acute TAAD were satisfactory. The time of mechanical ventilation and ICU stay was shorter in the modified group, and the drainage of 48 hours after surgery was less also.