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.

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.

Objective To evaluate the radiation impact of a self-developed digital miniature CT on the human body and the environment under simulated scanning conditions, and verify its safety and regulatory compliance. Methods Under typical head scanning conditions with the digital miniature CT (70 kV/10 mA), the equivalent doses received at the body surface sites corresponding to the thyroid, breast, stomach, liver, kidney, and gonads of the phantom were measured without protection and with 0.5 mmPb equivalent protection using LiF (Mg, Cu, P) thermoluminescent dosimeters. The ambient dose equivalent rates at the bed level inside the CT room at different directions and distances from the scanning center were measured using a model AT1121 X/γ dosimeter. The equivalent doses of organs on both sides of the phantom and the ambient equivalent dose rates on the left and right sides of the longitudinal axis of the bed in the CT room were compared. The Mann-Whitney test was used at a significance level of P < 0.05. Results During a single scan of the head with the digital miniature CT, the equivalent doses at the body surface sites corresponding to the thyroid, breast, stomach, liver, kidney, and gonads without protection were 1.04, 0.95, 0.55, 0.57, 0.40, and 0.12 mSv, respectively, which were only 0.84% to 8.24% of the doses inside the irradiation field. With 0.5 mm Pb equivalent protection, the equivalent dose of the thyroid decreased from 8.24 mSv to 3.27 mSv with a reduction of 60.3%, and the doses of the other organs were reduced to 1.5-11.5 μSv with the maximum reduction of 14 times. In the longitudinal axis direction of the CT bed, the ambient dose equivalent rate at a distance of 2 m from the scanning center was reduced to 0.066 mSv/h, which was only 9.6% of the ambient equivalent dose rate at a distance of 50 cm from the scanning center. Conclusion The digital miniature CT has advantages in ensuring patient safety, optimizing imaging quality, and promoting technological development, demonstrating promising application potential. However, the radiation protection of personal and CT room should not be ignored.

Objective: To investigate the clinical characteristics, the types of unexpected antibodies, and their impacts on immunological risks among patients with different frequencies of cross-matching incompatibility, so as to propose corresponding solutions. Methods: Data of cross-matching incompatibility samples from 92 medical institutions during 2022 to 2024 were collected and divided into three groups based on the frequency of cross-matching. Statistical analysis was performed on disease types, distribution of hematologic diseases, alloantibody detection rates, and proportions of alloantibody types. Results: The 858 patients were divided into three groups based on the frequency of blood cross-matching incompatibility: ≥5 times (8.28%, 71/858), 2 to 4 times (28.21%, 242/858); 1 time (63.52%, 545/858). There was a clustered distribution of disease types in the ≥5 cross-matchings group, with 71.83% (51/71) of patients having tumors or hematologic and hematopoietic diseases. In contrast, the disease types in the 2 to 4 cross-matchings and 1 cross-matching groups were more diverse. An analysis of 249 patients with hematologic diseases found that multiple myeloma was the most common disease in all three groups, accounting for 31.43% (11/35), 35.37% (29/82), and 37.88% (50/132) respectively. In the ≥5 cross-matchings group, myelodysplastic syndrome (14.29%, 5/35) and thalassemia (14.29%, 5/35) were the second most common diseases. In contrast, in the 2 to 4 cross-matchings group and 1 cross-matching group, autoimmune hemolytic anemia was the second most common disease, with prevalence rates of 20.73% (17/82) and 24.24% (32/132), respectively. Alloantibodies were detected in 54.66% of the patients, with antibodies against Rh blood group being most frequent (>50%) in all three groups. The detection rates of alloantibodies/alloantibodies with coexisting autoantibodies decreased across groups: the ≥5 cross-matchings group (70.42%, 50/71) > the 2 to 4 cross-matchings group (54.96%, 133/242) > the 1 cross-matching group (52.48%, 286/545). Conclusion: The risk of alloantibody production increases in patients with multiple cross-matching incompatibilities, especially in those with tumors or hematologic diseases. For handling of cross-matching incompatibility cases, it is recommended to optimize the cross-matching process, implement individualized transfusion plans, and enhance the technical capabilities of clinical transfusion departments and blood group reference laboratories to ensure the safety and effectiveness of transfusions.

ObjectiveTo investigate the trend and influencing factors of newly reported human immunodeficiency virus (HIV) positivity rate among men who had sex with men (MSM) in Shanghai from 2021 to 2024, and to provide evidence for formulating scientific prevention and control measures of AIDS. MethodsMultiple rounds of cross-sectional questionnaire surveys were conducted among MSM by Shanghai Qing’ai Health Promotion Center. Pearson and Cochran-Armitage trend χ² tests were used to analyze the differences and changes in population characteristics and newly reported HIV positivity rates. A logistic regression model was applied for multivariate analyses of factors associated with newly reported HIV positivity. ResultsA total of 1 653 MSM who had not been previously diagnosed with HIV infection were surveyed. The newly reported HIV positivity rates in 2021, 2023, and 2024 were 7.87%, 3.91%, and 3.06%, respectively, showing a decreasing trend (χ²_trend=13.460, P_trend<0.001). Multivariate analyses revealed that MSM aged 18‒<25 years, residing locally for <1 year, identifying as bisexual, lacking HIV knowledge, and having ≥10 same-sex partners in the past 6 months exhibited higher newly reported HIV positivity rates. Conversely, MSM knowledgeable about HIV prevention, residing locally for 1‒5 years, and engaging in oral sex with male partners in the past 6 months demonstrated lower HIV positivity rates. Annual analyses revealed that MSM with HIV knowledge had lower newly reported HIV positivity rates in 2023 and 2024 (aOR=0.300, 95%CI: 0.811‒0.111; aOR=0.202, 95%CI: 0.085‒0.483). ConclusionThe newly reported HIV positivity rate among MSM in Shanghai from 2021 to 2024 showed a decline. Future interventions should focus on young and mobile MSM, strengthen HIV knowledge education through platforms such as the internet, promote safe sexual behaviors and regular testing, and further expand the coverage of pre-exposure prophylaxis (PrEP) and post-exposure prophylaxis (PEP) to control HIV transmission within this population.