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 propose an improved Y OLOv8-based visible small target detection method to solve the problems of the UAV visible light system in accuracy and timeliness when applied to measuring small targets.Methods A YOLOv8 network consisting of Backbone,Neck and Head was used as the base framework to construct an AGC-YOLO model.Firstly,a convolutional block attention module(CBAM)was incorporated into Backbone to improve the feature expression of the model;secondly,some traditional convolution modules were replaced with the changeable kernel convolution module AKconv to reduce the network parameters;finally,a Gold-YOLO module was involved in Neck to enhance the detection ability for targets with different sizes.VisDrone2019 dataset was used to carry out ablation and comparison experiments,and the efficacy of the AGC-YOLO model for detecting small targets was evaluated in terms of mean average precision(mAP),frames per second(FPS),giga floating-point operations per second(GFLOPs)and parameters.Results The AGC-YOLO model had the FPS,GFLOPs and parameters being 31.90,9.20 and 11.30 M respectively,meeting the real-time detection speed requirements of drones(FPS not lower than 30),in which the mAP50(the mAP with the intersection over union being 0.5)was increased by 15％,6％and 5％when compared with those of the lightweight YOLOv8n,Ghost-YOLO and YOLO-BiFPN models.Conclusion The method proposed behaves well in speed,decreased parameters and precision,and is worthy promoting for UAV visible small target detection.[Chinese Medical Equipment Journal,2025,46(1):1-6]

Objective To obtain differential spectral characteristics of etomidate and its structural ana-logues,and to establish a rapid identification method using surface-enhanced Raman spectroscopy(SERS)combined with machine learning algorithms for distinguishing etomidate and its analogues.Methods Silver nanoparticles(AgNPs)were used as the SERS substrate to collect SERS spectra of etomidate,metomidate,propoxate,and isopropoxate at two concentrations of 1×10-4 and 1×10-5 mol/L.SERS spectra were also obtained from blood and urine samples containing 1×10-5 mol/L of etomidate,metomidate,propoxate,and isopropoxate,as well as from confiscated e-cigarette oil containing etomi-date.Uniform manifold approximation and projection(UMAP)was employed for nonlinear dimensiona-lity reduction and visualization,and a classification model based on the XGBoost algorithm was con-structed to enable discriminant analysis of these four structurally highly similar compounds.Results Mi-nor characteristic peak shifts(5-3 cm-1)were identified in the range of 1 398-811 cm-1.Qualitative identification of the compounds in serum,urine and e-cigarette oil samples was achieved without pre-treatment.After UMAP dimensionality reduction,distinct clustering separation among different sub-stances was observed.The XGBoost model achieved 100%classification accuracy on the test set.Feature weight analysis revealed that C-N stretching vibration(841 cm-1),C=O stretching vibration(1 367 cm-1),and C-O-C asymmetric vibration(1 049 cm-1)were the key spectral bands for discrimination.Conclu-sion The combination of SERS and machine learning can effectively amplify subtle differences in mo-lecular structures,enabling rapid and accurate identification of etomidate and its analogues.This ap-proach is suitable for on-site rapid screening in forensic toxicology.

Objective:To investigate the risk factors and prognosis of postoperative atrial fibrillation(POAF) and delayed-onset POAF(dPOAF).Methods:In a retrospective cohort study involving consecutive patients who underwent cardiac surgery across provincial cardiovascular consortium consisted of 57 hospitals in Jiangsu Province from January 2015 to December 2022, the incidence and implications of dPOAF were examined. dPOAF was defined as being diagnosed within 30 days of discharge.Results:Among 2 788 patients with postoperative new-onset POAF, 154(5.5%)cases had dPOAF, median onset time 21(15, 26)days following surgery. Compared to in-patient diagnosed POAF, dPOAF was associated with increased rates of hypertension(28.6% vs. 9.0%, P<0.001), diabetes(10.4% vs. 3.2%, P<0.001), heart failure(39.6% vs. 19.3%, P<0.001), peripheral vascular disease(13.6% vs. 2.2%, P<0.001), and higher CHA2DS2-VASc score(≥2)(59.8% vs. 43.2%, P<0.001). Female patients were less likely to develop dPOAF( OR=0.44, 95% CI: 0.30-0.63, P<0.001). During follow-up period, there was no significant difference in major adverse cardiovascular events(MACEs)( HR=1.33, 95% CI: 0.82-2.17), overall mortality( HR=0.58, 95% CI: 0.07-4.67), or thromboembolism events( HR=0.57, 95% CI: 0.26-1.25). Conclusion:This study underscores the risk factors and prognosis associated with dPOAF compared to in-hospital POAF. It highlights the imperative for vigilant monitoring and individualized management strategies tailored to patients at risk of dPOAF.

AIM:To investigate whether melatonin can ameliorate acute myocardial infarction(AMI)by in-hibiting ferroptosis.METHODS:H9C2 cells were cultured in AnaeroPack system with low sugar and serum-free medium for 10 h to construct a cell model of AMI.Then cells were treated with melatonin and ferroptosis inducer erastin.The cell activity,reactive oxygen species(ROS),lipid peroxidation,mitochondrial membrane potential(MMP),and ferroptosis related protein expression were detected.A rat model of AMI induced by isoprenaline(ISO)injection was established to evaluate the effects of melatonin,in which the myocardial infarction size,cardiac injury,pathological changes,oxidative stress,iron ion and ferroptosis related protein expression were examined.RESULTS:Melatonin decreased the oxidative stress,lipid peroxidation and expression of ferroptosis protein in cardiomyocytes induced by hypoxia,but these effects could be impeded by the ferroptosis inducer erastin.Furthermore,in vivo experiments,we also found that melatonin im-proved the myocardial infarction size,cardiac injury,pathological changes,oxidative stress,and alleviated iron ion accu-mulation and ferroptosis.CONCLUSION:The cardioprotective effects of melatonin in AMI are associated with the inhi-bition of ferroptosis.

Extensive epigenetic reprogramming involves in memory CD8+ T-cell differentiation. The elaborate epigenetic rewiring underlying the heterogeneous functional states of CD8+ T cells remains hidden. Here, we profile single-cell chromatin accessibility and map enhancer-promoter interactomes to characterize the differentiation trajectory of memory CD8+ T cells. We reveal that under distinct epigenetic regulations, the early activated CD8+ T cells divergently originated for short-lived effector and memory precursor effector cells. We also uncover a defined epigenetic rewiring leading to the conversion from effector memory to central memory cells during memory formation. Additionally, we illustrate chromatin regulatory mechanisms underlying long-lasting versus transient transcription regulation during memory differentiation. Finally, we confirm the essential roles of Sox4 and Nrf2 in developing memory precursor effector and effector memory cells, respectively, and validate cell state-specific enhancers in regulating Il7r using CRISPR-Cas9. Our data pave the way for understanding the mechanism underlying epigenetic memory formation in CD8+ T-cell differentiation.
CD8-Positive T-Lymphocytes/metabolism* ; Cell Differentiation ; Chromatin/immunology* ; Animals ; Mice ; Immunologic Memory ; Epigenesis, Genetic ; SOXC Transcription Factors/immunology* ; NF-E2-Related Factor 2/immunology* ; Mice, Inbred C57BL ; Gene Regulatory Networks ; Enhancer Elements, Genetic

This study aims to investigate the protective effects and mechanisms of polysaccharide extract PCP1 from Polygonatum cyrtonema in ameliorating cerebral ischemia-reperfusion(I/R) injury in rats through modulation of the Toll-like receptor 4(TLR4)/NOD-like receptor protein 3(NLRP3) signaling pathway. In vivo, SD rats were randomly divided into the sham group, model group, PCP1 group, nimodipine(NMDP) group, and TLR4 signaling inhibitor(TAK-242) group. A middle cerebral artery occlusion/reperfusion(MCAO/R) model was established, and neurological deficit scores and infarct size were evaluated 24 hours after reperfusion. Hematoxylin-eosin(HE) and Nissl staining were used to observe pathological changes in ischemic brain tissue. Transmission electron microscopy(TEM) assessed ultrastructural damage in cortical neurons. Enzyme-linked immunosorbent assay(ELISA) was used to measure the levels of interleukin-1β(IL-1β), interleukin-6(IL-6), interleukin-18(IL-18), tumor necrosis factor-α(TNF-α), interleukin-10(IL-10), and nitric oxide(NO) in serum. Immunofluorescence was used to analyze the expression of TLR4 and NLRP3 proteins. In vitro, a BV2 microglial cell oxygen-glucose deprivation/reperfusion(OGD/R) model was established, and cells were divided into the control, OGD/R, PCP1, TAK-242, and PCP1 + TLR4 activator lipopolysaccharide(LPS) groups. The CCK-8 assay evaluated BV2 cell viability, and ELISA determined NO release. Western blot was used to analyze the expression of TLR4, NLRP3, and downstream pathway-related proteins. The results indicated that, compared with the model group, PCP1 significantly reduced neurological deficit scores, infarct size, ischemic tissue pathology, cortical cell damage, and the levels of inflammatory factors IL-1β, IL-6, IL-18, TNF-α, and NO(P<0.01). It also elevated IL-10 levels(P<0.01) and decreased the expression of TLR4 and NLRP3 proteins(P<0.05, P<0.01). Moreover, in vitro results showed that, compared with the OGD/R group, PCP1 significantly improved BV2 cell viability(P<0.05, P<0.01), reduced cell NO levels induced by OGD/R(P<0.01), and inhibited the expression of TLR4-related inflammatory pathway proteins, including TLR4, myeloid differentiation factor 88(MyD88), tumor necrosis factor receptor-associated factor 6(TRAF6), phosphorylated nuclear factor-kappaB dimer RelA(p-p65)/nuclear factor-kappaB dimer RelA(p65), NLRP3, cleaved-caspase-1, apoptosis-associated speck-like protein(ASC), GSDMD-N, IL-1β, and IL-18(P<0.05, P<0.01). The protective effects of PCP1 were reversed by LPS stimulation. In conclusion, PCP1 ameliorates cerebral I/R injury by modulating the TLR4/NLRP3 signaling pathway, exerting anti-inflammatory and anti-pyroptotic effects.
Animals ; Toll-Like Receptor 4/genetics* ; NLR Family, Pyrin Domain-Containing 3 Protein/genetics* ; Rats, Sprague-Dawley ; Rats ; Reperfusion Injury/genetics* ; Male ; Signal Transduction/drug effects* ; Polysaccharides/isolation & purification* ; Polygonatum/chemistry* ; Brain Ischemia/genetics* ; Drugs, Chinese Herbal/administration & dosage* ; Mice ; Humans

Objective To investigate the association between the Chinese visceral adiposity index (CVAI) and diabetes mellitus, hypertension, diabetes mellitus or hypertension, and diabetes with hypertension among elderly people in Hebei Province. Methods In 2020, a stratified multi-stage random sampling was used to conduct questionnaire survey, physical examination and laboratory detection among permanent residents of 10 monitoring sites in Hebei Province. Logistic regression was used to analyze the association between CVAI and diabetes mellitus, hypertension, diabetes mellitus or hypertension, and diabetes with hypertension. The area under the ROC curve (AUC) was used to evaluate the predictive value of CVAI for diabetes mellitus, hypertension, diabetes mellitus or hypertension, and diabetes with hypertension. Results The detection rates of diabetes mellitus, hypertension, diabetes mellitus or hypertension, and diabetes with hypertension were 19.8%, 74.6%, 78.2%, and 16.2%, respectively. Multivariate logistic regression analysis showed that compared with the lowest quartile of CVAI group Q1, the OR (95% CI) of diabetes mellitus, hypertension, diabetes mellitus or hypertension, and diabetes with hypertension in the highest quartile Q4 group were 3.55 (2.58~4.89), 2.52 (1.92~3.31), 3.09 (2.31~4.12), and 4.92 (3.40~7.12), respectively. The ROC curve results showed that CVAI had the best predictive value in the diagnosis of diabetes with hypertension, and the optimized critical values in males and females were 128.54 and 141.88, respectively. Conclusion The detection rates of diabetes mellitus and hypertension are high in the elderly population in Hebei Province. CVAI is positively associated with the risk of diabetes mellitus, hypertension, diabetes mellitus or hypertension, and diabetes with hypertension among the elderly in Hebei. CVAI has the strongest prediction ability for diabetes with hypertension.

In recent years,significant breakthroughs have been achieved in the immunotherapy for Alzheimer's disease.In line with global advancements,two anti-amyloid-β monoclonal antibodies have been approved and successfully launched in China for clinical use.Lecanemab and Donanemab were officially used in June 2024 and April 2025 in China,respectively.In order to standardize the rational and safe application of anti-amyloid-β monoclonal antibodies for Alzheimer's disease in China,this article integrates recom-mendations from the clinical trials and real-world experience from the author's team and domestic peers to further update the recom-mendations for the clinical use of anti-amyloid-β monoclonal antibody based on the 2024 version.It includes indications for therapy,pre-treatment evaluation and preparation,administration protocols and safety measures during treatment,and post-treatment monitor-ing strategies.

Aim To investigate the effect of cordycepin(COR)on gentamicin(GEN)-induced nephrotoxicity and the molecular mechanism of inhibiting oxidative stress and ferroptosis induced by GEN.Methods The oral SD rats were divided into a control group,GEN group,and GEN+COR group.Following the success-ful setting up of the animal model,the serum creatinine(CR)and urea nitrogen(BUN)levels of rats were measured,and renal tissue injury was assessed using HE staining.In addition,the contents of malondialde-hyde and glutathione in kidney tissues of SD rats in each group were detected,and the expressions of fer-roptosis markers GPX4 and SLC7A11 were analyzed by Western blot.Results Compared with the control group,CR and BUN in GEN-stimulated group signifi-cantly increased(P＜0.01),and the level of CR and BUN was effectively reduced after 50 mg·kg-1 COR oral administration.HE results also showed that COR could alleviate the kidney tissue damage caused by GEN.COR could reverse the increase of malondialde-hyde level and the decrease of glutathione level caused by GEN in rat kidney tissue,and COR could restore the decrease of GPX4 and SLC7A11 protein levels induced by GEN.Conclusion COR can reduce GEN-induced kidney injury by inhibiting oxidative stress and ferrop-tosis.