Objective: To investigate the status of condom use and its influencing factors among men who have sex with men (MSM), so as to provide a basis for improving condom utilization rates and AIDS prevention and control in this population. Methods: From May to October 2024, a snowball sampling method was employed to recruit MSM in Songjiang District, Shanghai Municipality. Self-administered questionnaires were used to collect data on demographic characteristics, AIDS-related knowledge, sexual behaviors, pre-exposure prophylaxis (PrEP) and post-exposure prophylaxis (PEP), and condom use in the past six months. Multivariable logistic regression model was used to analyze the influencing factors for consistent condom use. Results: A total of 921 MSM were surveyed, with a median age of 29.00 (interquartile range, 9.00) years. Among them, 697 (75.68%) were aware of AIDS-related knowledge, 826 (89.69%) expressed willingness to use PrEP, and 835 (90.66%) were willing to use PEP. Additionally, 787 (85.45%) MSM reported their age at first homosexual intercourse as ≥18 years, while 519 (56.35%) reported consistent condom use in the past six months. Multivariable logistic regression analysis revealed that MSM who were aware of AIDS-related knowledge (OR=0.582, 95% CI: 0.423-0.801), willing to use PrEP (OR =0.611, 95% CI: 0.385-0.969), and whose age at first homosexual intercourse was <18 years (OR=0.480, 95% CI: 0.330-0.700) were less likely to consistent use condoms. Conclusion The proportion of consistent condom use among the MSM remains relatively low, which is primarily associated with AIDS-related knowledge, willingness to use PrEP, and the age at first homosexual intercourse.

The functional realization of proteins and other biological macromolecules depends on conformational dynamics and allosteric regulation, and elucidating their molecular mechanisms is an important foundation for understanding life processes. Molecular dynamics simulations are a powerful tool for investigating conformational evolution at the atomic level. However, traditional methods are limited by simulation timescales and high free-energy barriers, making it difficult to effectively capture rare conformations and their transition pathways. As a result, the development of enhanced sampling techniques has become key to overcoming this bottleneck. As a classical enhanced sampling technique, metadynamics suffers from several shortcomings, including strong dependence on collective variables and significant errors caused by bias potential accumulation. This article reviews three major improvement strategies. The first combines stochastic resetting with metadynamics, using trajectory-resetting mechanisms to improve sampling efficiency while avoiding the difficulty of optimizing collective variables. The second, SinkMeta, employs a “sinking” bias effect to enable efficient exploration of specific regions and paths. The third, OPES-based hybrid methods, improve the stability of free-energy estimation by optimizing the target distribution or the way the bias is constructed. These methods provide new ideas for characterizing free-energy landscapes and studying conformational transitions in complex biological systems, while also promoting the continued development of enhanced sampling methodologies.

Objective: To analyze the implementation status of the “Three-Exemptions” policy for voluntary blood donation in China by taking Shandong Province as a case study, explore the sociodemographic characteristics of policy beneficiaries and the distribution differences in blood donation frequencies, so as to provide practical references for improving the honor incentive system of voluntary blood donation and stabilizing the blood donation team. Methods: Excel was used to sort out and summarize the policy documents from 31 provincial-level administrative regions of China (excluding Hong Kong, Macao and Taiwan), and its implementation models, temporal characteristics and implementation basis were analyzed. Using 238 193 policy beneficiaries in Shandong Province as the research objects, Stata was adopted for descriptive statistical analysis of sociodemographic characteristics including gender, age, educational background and occupation. The Mann-Whitney U test and Kruskal-Wallis H test were performed to compare the distribution differences of blood donation frequencies among populations with different characteristics. Results: The “Three Exemption” policy has been implemented in 29 provinces nationwide, forming five differentiated implementation models. Specifically, 45.16% of the regions adopted province-wide unified implementation, 32.26% adopted partial prefecture-level city implementation, 12.90% adopted partial clause implementation, 3.23% adopted encouraging implementation, and 6.45% had not implemented the policy. The period from 2023 to 2026 witnessed the concentrated promotion of the policy. In Shandong Province, the beneficiaries were mainly males (82.08%), middle-aged individuals aged 40-60 years (71.78%), groups with junior and senior high school education (56.57%), and staff employees (30.60%). The distribution of blood donation frequencies showed that nearly 60% (56.95%) of the beneficiaries had donated blood 20 to 29 times. Statistically significant differences in donation frequency distributions were observed across genders, age groups, educational backgrounds, and occupations (all P<0.05). Further analysis revealed that the proportion of males with 40 or more blood donations was higher than that of females (24.32% vs 15.60%), while females had a higher proportion of 20-29 blood donations than males (65.98% vs 54.99%). With the increase of age, the proportion of those with 20-29 blood donations gradually decreased, whereas the proportion of those with≥40 blood donations gradually increased. Conclusion: The coverage of the “Three Exemptions” policy for voluntary blood donation in China continues to expand. However, there is still room for optimization in terms of policy implementation standards, population structure adaptation and incentive gradient design. Future efforts should strengthen national top-level design to balance regional development gaps. Moreover, hierarchical and targeted incentive and publicity strategies combined with population structural characteristics should be implemented to enhance public enthusiasm for voluntary blood donation.

ObjectiveTo investigate the effect of the nitroglycerin-controlled low central venous pressure （CLCVP） technique on brain metabolic markers and cerebral blood oxygen saturation in patients undergoing laparoscopic hepatectomy for liver cancer， and to reduce the risk of neurological complications. MethodsA total of 105 patients who underwent elective laparoscopic hepatectomy for liver cancer in Haikou Hospital Affiliated to Xiangya Hospital of Central South University from April 2020 to May 2023 were enrolled and randomly divided into CLCVP group with 54 patients and non-CLCVP group with 51 patients. The patients in the CLCVP group were treated with the nitroglycerin CLCVP technique during surgery， while those in the non-CLCVP group were given conventional surgical treatment. The two groups were compared in terms of the following indicators： perioperative indicators； hemodynamic parameters and cerebral oxygen metabolism before anesthesia induction （T0）， at 5 minutes after anesthesia induction （T1）， at 5 minutes after the beginning of liver parenchyma dissection （T2）， at 5 minutes after the end of hepatectomy （T3）， and immediately after the end of surgery （T4）； the changes in liver function parameters after surgery； the incidence rate of adverse reactions. The independent-samples t test was used for comparison of continuous data between two groups， and the chi-square test was used for comparison of categorical data between two groups； the analysis of variance with repeated measures was used for comparison between multiple time points. ResultsCompared with the non-CLCVP group， the CLCVP group had significantly lower intraoperative blood loss and intraoperative fluid infusion volume （t=5.408 and 7.220， both P<0.05）， while there were no significant differences between the two groups in time of operation， anesthesia time， extubation time， resuscitation time and intraoperative urine volume （all P>0.05）. Compared with the data at T0， both groups had significant reductions in mean arterial pressure， heart rate， and central venous pressure during surgery （all P<0.05）， and compared with the non-CLCVP group， the CLCVP group had significantly lower mean arterial pressure and central venous pressure （P<0.05） and a significantly higher heart rate （P<0.05） at T2 and T3. Compared with the data at T0， both groups had a significant reduction in Ca-jvDO₂ at T2‍ ‍—‍ ‍T4 time points （all P<0.05）， while there was no significant difference in Ca-jvDO₂ between the two groups at each time point （all P>0.05）. Compared with the data at T0， the CLCVP group had a significant reduction in rSO₂ at T2‍ ‍—‍ ‍T4 time points （all P<0.05）， and the CLCVP group had a significantly lower level of rSO₂ than the non-CLCVP group at T2‍ ‍—‍ ‍T3 time points （both P<0.05）； there were no significant changes in CERO₂ and Djv-aBL in either group at each time point （all P>0.05）. At 3 and 7 days after surgery， both groups had significant increases in the liver function parameters of aspartate aminotransferase （AST）， alanine aminotransferase （ALT）， and total bilirubin （TBil） （all P<0.05）， and the CLCVP group had significantly lower levels of AST and ALT than the non-CLCVP group （all P<0.05）； there was no significant difference in TBil between the two groups at each time point （all P>0.05）. There was no significant difference in the incidence rate of perioperative complications between the two groups （χ²=0.729， P=0.394）. ConclusionThe application of the nitroglycerin CLCVP technique in laparoscopic hepatectomy for liver cancer can reduce the amount of intraoperative blood loss in patients， but it is necessary to further enhance the monitoring of cerebral blood oxygen saturation during surgery， so as to reduce the risk of neurological complications as much as possible.

Objective: To understand relationship of positive and negative peer events with mental health problems among college students, so as to provide a scientific basis for improving mental health level of college students. Methods: A total of 1 640 freshmen to juniors were randomly selected from two universities in Anhui Province from October to November 2023 by a combination of convenience sampling and cluster random sampling method. The positive and negative peer events, self perceived loneliness and stress levels, anxiety and depression symptoms of students were investigated by using the questionnaire star online. Group comparisons were conducted by using analysis of variance and Chi square test, and multivariate binary Logistic regression and linear regression were used to analyze relationship of positive and negative peer events with mental health problems among college students. Results: About 35.4% of college students reported that they experienced at least one type of negative peer events, and 91.3% reported that they experienced at least one type of positive peer events. After controlling for covariates,multivariate regression analysis found that experiencing 1, ≥2 types of negative peer events were positively correlated with loneliness scores of college students ( β = 1.36,4.04), as well as an increased risk of anxiety symptoms ( OR =2.24,4.33) and depression symptoms ( OR =2.19,4.01); and experiencing ≥2 types of negative peer events was positively correlated with stress scores of college students ( β =1.12)( P <0.05). Experiencing 5-6 and 7 types of positive peer events were negatively correlated with loneliness scores of college students ( β = -1.79, -2.44) and stress ( β =-0.75, -1.12); and experiencing 7 types of positive peer events were associated with a lower risk of anxiety symptoms ( OR =0.74) and depressive symptoms ( OR =0.80) ( P <0.05). The number of negative peer events was positively correlated with loneliness scores ( β =0.80) and stress scores( β =0.24), as well as the risk of anxiety symptoms ( OR =1.30) and depressive symptoms ( OR =1.27) among college students ( P <0.05). The number of positive peer events involved was negatively correlated with loneliness scores( β =-0.39) and stress scores( β =-0.19), as well as the risk of anxiety ( OR =0.92) and depressive symptoms ( OR =0.93) among college students ( P <0.05). The analysis of the moderating effect found that in different groups of positive peer events, reporting 1, ≥2 negative peer events were positively correlated with loneliness scores of college students ( β=1.08- 4.96), as well as an increased risk of anxiety symptoms ( OR =1.79-6.20) and depression symptoms ( OR =1.78-6.77) ( P <0.05); and β and OR coefficients were highest in the group reporting 0-4 types of positive peer events, followed by the group reporting 5-6 types of positive peer events, with lowest coefficients in the group reporting 7 types of positive peer events. Conclusions Negative peer events are positively correlated with psychological problems in college students, and positive peer events are negatively correlated with mental health problems. Positive peer events could alleviate the impact of negative peer events on mental health problems.

Objective: To explore the correlation among picky eating levels in preschool children, parental self-efficacy and parenting stress. Methods: A convenience sampling method was employed to conduct an electronic questionnaire survey among 459 children aged 3-6 years and their parents from five kindergartens in Urumqi in November 2023. The survey included a general information questionnaire, the Children s Eating Behavior Questionnaire (CEBQ), the Parenting Sense of Competence Scale (PSOC), and the Parenting Stress Index-Short Form (PSI-SF). The Mann-Whitney U-test was used for twogroup comparisons, and the Kruskal-Wallis H-test was applied for multi-group comparisons. Spearman correlation analysis was conducted to examine the relationships between children s picky eating levels and parenting selfefficacy as well as parenting stress. Results: The picky eating score of preschool children was 10.00 (4.00), and the parenting self-efficacy score was 58.00 (12.00), both indicating a moderate level. The parenting stress score was 75.00 (16.00), reflecting a moderately low level. Spearman correlation analysis showed that children s picky eating levels were negatively correlated with the total score of parenting self-efficacy ( r =-0.28) and positively correlated with the total score of parenting stress( r =0.25)( P <0.01). Conclusions Picky eating levels of preschool children are closely associated with parenting self-efficacy and parenting stress. Picky eating behaviors in children can be reduced by implementing various effective measures to enhance parenting self-efficacy and alleviate parenting stress.

Alzheimer’s disease (AD) is a chronic neurodegenerative disorder that severely affects the health of the elderly, marked by its incurability, high prevalence, and extended latency period. The current approach to AD prevention and treatment emphasizes early detection and intervention, particularly during the pre-AD stage of mild cognitive impairment (MCI), which provides an optimal “window of opportunity” for intervention. Clinical detection methods for MCI, such as cerebrospinal fluid monitoring, genetic testing, and imaging diagnostics, are invasive and costly, limiting their broad clinical application. Speech, as a vital cognitive output, offers a new perspective and tool for computer-assisted analysis and screening of cognitive decline. This is because elderly individuals with cognitive decline exhibit distinct characteristics in semantic and audio information, such as reduced lexical richness, decreased speech coherence and conciseness, and declines in speech rate, voice rhythm, and hesitation rates. The objective presence of these semantic and audio characteristics lays the groundwork for computer-based screening of cognitive decline. Speech information is primarily sourced from databases or collected through tasks involving spontaneous speech, semantic fluency, and reading, followed by analysis using computer models. Spontaneous language tasks include dialogues/interviews, event descriptions, narrative recall, and picture descriptions. Semantic fluency tasks assess controlled retrieval of vocabulary items, requiring participants to extract information at the word level during lexical search. Reading tasks involve participants reading a passage aloud. Summarizing past research, the speech characteristics of the elderly can be divided into two major categories: semantic information and audio information. Semantic information focuses on the meaning of speech across different tasks, highlighting differences in vocabulary and text content in cognitive impairment. Overall, discourse pragmatic disorders in AD can be studied along three dimensions: cohesion, coherence, and conciseness. Cohesion mainly examines the use of vocabulary by participants, with a reduction in the use of nouns, pronouns, verbs, and adjectives in AD patients. Coherence assesses the ability of participants to maintain topics, with a decrease in the number of subordinate clauses in AD patients. Conciseness evaluates the information density of participants, with AD patients producing shorter texts with less information compared to normal elderly individuals. Audio information focuses on acoustic features that are difficult for the human ear to detect. There is a significant degradation in temporal parameters in the later stages of cognitive impairment; AD patients require more time to read the same paragraph, have longer vocalization times, and produce more pauses or silent parts in their spontaneous speech signals compared to normal individuals. Researchers have extracted audio and speech features, developing independent systems for each set of features, achieving an accuracy rate of 82% for both, which increases to 86% when both types of features are combined, demonstrating the advantage of integrating audio and speech information. Currently, deep learning and machine learning are the main methods used for information analysis. The overall diagnostic accuracy rate for AD exceeds 80%, and the diagnostic accuracy rate for MCI also exceeds 80%, indicating significant potential. Deep learning techniques require substantial data support, necessitating future expansion of database scale and continuous algorithm upgrades to transition from laboratory research to practical product implementation.

Hepatitis B is a major global public health issue. Through the implementation of comprehensive prevention and control strategies centered on hepatitis B vaccination， China has achieved remarkable progress in hepatitis B prevention and control， while there are still many issues and challenges. This article reviews the development of hepatitis B vaccination strategies in China， analyzes the goal and advances in vaccination in different populations， and problems and challenges， in order to provide a reference for further optimizing vaccination strategies and improving the levels of prevention and control.

[Objective] To analyse the distribution of antigen phenotypes in the Rh, MNS and Kidd blood group systems of Han and Tujia blood donors in Chongqing, and to provide data support for the establishment of an expanded blood group antigen phenotype database and the development of expanded blood group coordinated transfusion in blood donors. [Methods] The antigens of Rh, MNS and Kidd blood group systems in Han and Tujia blood donors in Chongqing were detected by test-tube method, and the Hardy-Weinborg anastomosis of the three blood group systems was calculated. Pearson's chi-square test and Fisher's exact probability method were used to compare the differences in phenotypic distribution frequencies among different regions and ethnic groups. [Results] Han and Tujia blood donors accounted for the highest proportion of CCee in the antigenic phenotype of the Rh blood group system, followed by CcEe, and then Ccee and ccEE. Tujia blood donors accounted for 52.02% of CCee, which was higher than that of Han blood donors (47.24%), while Han blood donors accounted for 32.20% of CcEe, which was higher than that of Tujia blood donors (28.94%). In the antigenic phenotype of the MNS blood group system, the blood donors of Han nationality and Tujia were MN>MM>NN,. The antigen phenotype distribution frequency of the Kidd blood group system was highest for Jk(a+b+) among both Han and Tujia blood donors, and the blood donors of Han nationality were Jk(a+b+)>Jk(a+b+), while those of Tujia were Jk(a-b+)>Jk(a+b-). The antigens of the three blood groups of Han and Tujia blood donors were consistent with the Hardy-Weinberg balance(P>0.05). There was no statistically significant difference in the frequency of antigen phenotypes of the three blood group systems between Han and Tujia blood donors(P>0.05). There were statistically significant differences in the phenotypic distribution frequency of Rh antigens between Chongqing and Xi'an, Zhejiang, Shantou, Foshan, Nanning and Yangzhou(P<0.05), but not with Guang'an and Shenzhen(P>0.05). There were statistically significant differences in the phenotypic distribution frequency of Rh antigens between Han, Tujia, Zang, Mongolian, Korean and Hani ethnic groups in Chongqing(P<0.05). There were statistically significant differences in the phenotypic distribution frequency of MNS antigens between Han blood donors in Chongqing and Urumqi, Hainan and Yuncheng, but not with Xi'an and Wenzhou. There was a statistically significant difference in the phenotypic distribution frequency of MNS antigen between Tujia blood donors in Chongqing and Urumqi and Hainan(P<0.05), but there was no significant difference in the phenotypic distribution frequency of MNS antigen between Tujia blood donors in Chongqing, Urumqi and Hainan(P>0.05). There was a statistically significant difference in the phenotypic distribution frequency of Kidd antigens between blood donors in Chongqing and Harbin(P<0.05), but not in Huizhou, Wenzhou and Yichang(P>0.05). [Conclusion] The population in Chongqing has multi-ethnic characteristics, and the antigenic phenotypes of Rh, MNS and Kidd blood group systems exhibit diversity and regional differences. Establishing an expanded blood bank can provide more options for precision blood transfusion.

ObjectiveTo investigate the role of serum HBV RNA in assessing antiviral therapy for patients with chronic hepatitis B， as well as its potential as a biomarker in clinical therapy， and to provide a scientific basis for the clinical treatment of chronic hepatitis B. MethodsA total of 134 patients who were diagnosed with chronic HBV infection in The Second Affiliated Hospital of Kunming Medical University from April 2023 to May 2024 were enrolled as subjects， and related examinations were performed， including HBV DNA， serum HBV RNA， liver function， HBsAg， anti-HBs， HBeAg， anti-HBe， anti-HBc， and transient elastography of the liver. The independent-samples t test or the Mann-Whitney U test was used for comparison of continuous data between two groups， and the Kruskal-Wallis H test was used for comparison between multiple groups； the chi-square test or the continuity-adjusted chi-square test was used for comparison of categorical data between two groups. Pearson correlation analysis or Spearman correlation analysis was performed. ResultsThe 134 patients with chronic HBV infection were divided into HBeAg-positive group with 45 patients and HBeAg-negative group with 89 patients， and there were significant differences between the two groups in age， the positive rate and quantitative value of HBV DNA， the positive rate and quantitative value of serum HBV RNA， HBsAg， anti-HBe， and ALT （all P<0.05）. In the cohort study of the HBeAg negative group， there were significant differences in the levels of HBV DNA， HBsAg， and GGT between the serum HBV RNA-negative group with 14 patients and the serum HBV RNA-positive group with 75 patients （all P<0.05）. There were 28 patients in the HBeAg-positive group and 62 in the HBeAg-positive group who used antiviral drugs for ≥1 month， and the 28 HBeAg-positive patients had an HBV RNA positive rate of 100%， while for the 62 HBeAg-negative patients， there were significant differences in the positive rate and level of serum HBV RNA between the patients with different durations of medication （both P<0.05）. Among the 89 HBeAg-negative patients， there were 62 treatment-experienced patients and 27 treatment-naïve patients， and there was a significant difference between the two groups in HBV RNA level ［2.07 （1.52 — 2.82） log₁₀ copies/mL vs 2.69 （1.80 — 3.55） log₁₀ copies/mL， Z=2.034， P=0.042］. For HBeAg-negative patients， serum HBV RNA was positively correlated with HBV DNA and HBsAg （both P<0.05）， and for HBeAg-positive patients， serum HBV RNA was significantly positively correlated with HBV DNA， HBsAg， and HBeAg （all P<0.05）. ConclusionAntiviral therapy can reduce viral load， and for HBeAg-negative patients with high-sensitivity HBV DNA below the lower limit of detection， serum HBV RNA can fill the “gap” in the detection of viral replication.