ObjectiveThe frequency difference limen (FDL) serves as a fundamental metric utilized for effectively quantifying the precise perceptual capabilities of the central auditory system. However, traditional measurement methods rely heavily on the active behavioral responses of subjects and are consequently highly susceptible to the negative influence of confounding subjective factors. Furthermore, existing research paradigms frequently employ uniform stimulus configurations that overlook critical individual perceptual differences. Based on brain-computer interface (BCI) technology, this comprehensive study aims to establish an objective and quantitative evaluation method for auditory frequency discrimination by systematically analyzing and decoding the specific neural responses elicited at the exact threshold state. MethodsWe designed a personalized rapid serial auditory presentation (RSAP) paradigm customized based on each individual’s precise FDL. A cohort of eleven healthy participants was recruited to evaluate the paradigm using pure-tone sequences at a baseline frequency of 4 000 Hz. This experimental paradigm simulates a realistic auditory perception environment through the continuous presentation of acoustic stimuli, thereby allowing for an in-depth investigation into the specific neural representations evoked by weak frequency deviations at the threshold state. Given that auditory stimulus-evoked response features exhibit complex and differentiated spatiotemporal distribution patterns across multiple frequency domains, this study further deeply integrates the cross-scale feature interaction module with the dynamic spatiotemporal attention allocation strategy, innovatively proposing the Multi-Scale Spatial-Temporal Dual Attention Network (MS-STAMNet). Specifically, the network constructs parallel processing branches with multiple receptive fields and introduces a dynamic adaptive weighting strategy to precisely localize core neural activity signals, further deeply integrating multi-scale information through cross-branch feature information interaction to achieve robust single-trial decoding of weak auditory evoked responses. ResultsThe comprehensive electrophysiological data analysis demonstrated that subtle auditory frequency deviation stimuli presented at the threshold level successfully elicited pronounced N2 and P3 event-related potential features, reflecting pre-attentive mismatch detection and subsequent cognitive evaluation, which were prominently distributed over the frontal, central, and temporal regions of the scalp. In the complex time-frequency domain, the extracted neural response characteristics exhibited distinct, statistically significant event-related synchronization within both the low-frequency δ and θ frequency bands, which was simultaneously accompanied by a widespread, prominent event-related desynchronization within the higher α band. A comparative analysis of model performance demonstrated that MS-STAMNet achieved an average unweighted average recall (UAR) of (69.67±6.12)% and area under the curve (AUC) of 0.761 8±0.07, significantly outperforming the established baseline models such as EEGNet and PLNet. Furthermore, a distinct dissociation phenomenon was verified between neural decoding and behavioral performance through regression analysis (R²=0.016, P=0.709), indicating that this model can effectively capture the implicit features of subtle frequency deviations, even when they fail to trigger explicit conscious responses. Additionally, attention weight visualization analysis further reveals the highly accurate focus of the network on key features concentrated over the bilateral temporal and fronto-parietal regions. ConclusionThis study systematically and comprehensively uncovers the multi-dimensional spatiotemporal evolutionary patterns of complex neural responses processing subtle acoustic variations under long-sequence threshold auditory stimulation. Concurrently, it verifies the efficacy and robustness of the proposed MS-STAMNet architecture in accurately deciphering weak, single-trial electroencephalogram signals amidst complex background noise. Ultimately, these neurophysiological and algorithmic findings lay a solid theoretical and methodological foundation for the objective and quantitative evaluation of individual auditory cognitive capabilities in clinical applications, transcending the fundamental limitations of traditional behavioral paradigms and providing robust technical support for future auditory research and related clinical assessments.

The time-sensitive medical treatment advantages of unmanned aerial vehicles(UAVs)in casualty evacuation were described,along with their typical application scenarios and the principles of casualty evacuation.The development status of UAV-based casualty evacuation,both domestically and internationally,was reviewed.Key life-support technologies,such as intelligent injury recognition,fully automated cardiopulmonary resuscitation(CPR)and auto cruise-based mecha-nical ventilation,were examined as important research directions of casualty evacuation UAVs.Finally,future development trends in UAV casualty evacuation and transport system were envisioned from four dimensions of autonomous flight technology,life support systems,information interaction and policy regulations.

Objective:To investigate the preferences and influencing factors of Traditional Chinese Medicine(TCM)health management services among community healthcare workers,providing a reference for promoting and spreading TCM health management services in communities.Methods:Based on a discrete choice experiment,a questionnaire survey was conducted among 596 community healthcare workers across 9 administrative districts in Beijing.A mixed logit model was used to analyze their preferences.Results:Changes in post-tax monthly income,expected efficacy,single-service duration,technical difficulty,patient compliance,and insurance coverage significantly influenced community doctors'service preferences.Changes in post-tax monthly income had the highest relative importance(35.11%),followed by insurance coverage(34.87%).Preferences varied among healthcare workers with different professional titles,backgrounds,weekly working hours,and whether the service was included in performance evaluations.Conclusion:Both economic and non-economic factors influence community healthcare workers'service preferences to varying degrees.Optimizing the combination of TCM health management service attributes can enhance community healthcare workers'willingness to provide such services.It is recommended to use a combination of economic and non-economic incentive measures and develop differentiated strategies for healthcare workers with different characteristics to meet their service preferences and promote the development of TCM health management services in communities.

The time-sensitive medical treatment advantages of unmanned aerial vehicles(UAVs)in casualty evacuation were described,along with their typical application scenarios and the principles of casualty evacuation.The development status of UAV-based casualty evacuation,both domestically and internationally,was reviewed.Key life-support technologies,such as intelligent injury recognition,fully automated cardiopulmonary resuscitation(CPR)and auto cruise-based mecha-nical ventilation,were examined as important research directions of casualty evacuation UAVs.Finally,future development trends in UAV casualty evacuation and transport system were envisioned from four dimensions of autonomous flight technology,life support systems,information interaction and policy regulations.

Objective:To investigate the predictive value of anti-Müllerian hormone (AMH) on the outcome of microscopic testicular sperm extraction (micro-TESE) in patients with non-mosaic Klinefelter syndrome (KS) of the clinical data and to identify effective predictors for successful micro-TESE.Methods:A retrospective case-control study was conducted on the clinical data of 118 non-mosaic KS patients treated at the Center for Reproductive Medicine of the First Affiliated Hospital of Zhengzhou University between May 2018 and September 2023. Patients were divided into two groups based on whether sperm were successfully retrieved via micro-TESE: the sperm retrieved group ( n=45) and the no sperm retrieved group ( n=73). Differences between the two groups were compared, and multivariate logistic regression analysis was used to identify factors influencing sperm retrieval. Changes in testicular volume and sex hormone levels before and after surgery were also assessed. Results:The sperm retrieval rate was 38.1% (45/118). Patients in the sperm retrieved group were significantly younger [(26.93±3.80) years] than those in the no sperm retrieved group [(28.27±3.92) years, P=0.029], and the AMH level was significantly higher [0.44 (0.18, 1.13) μg/L] than that in the no sperm retrieved group [0.10 (0.03, 0.22) μg/L, P<0.001]. AMH was identified as an independent predictor of micro-TESE outcome in non-mosaic KS patients ( OR=7.867, 95% CI: 2.727-27.242, P=0.001). The area under the receiver operating characteristic curve was 0.802 (95% CI: 0.722-0.883), and the optimal reference threshold for AMH was ≥0.265 μg/L. Postoperatively, testosterone levels decreased significantly by a median of 0.27 μg/L ( P=0.019), while luteinizing hormone levels increased by a median of 2.08 U/L ( P=0.049), with a more significant decline in testosterone levels observed in the no sperm retrieved group by a median of 0.29 μg/L ( P=0.022). Conclusion:AMH can predict successful micro-TESE in non-mosaic KS patients, with higher AMH levels indicating a higher likelihood of success.

Objective:To construct a rat model of osteoporosis induced by lead exposure, simulate the effects of lead exposure on the skeletal system of rats, and provide reliable basic data support for subsequent research.Methods:In July 2021, 40 eight-week-old SPF-grade SD rats were selected and randomly divided into 5 experimental groups according to body weight stratification randomization: blank control group, positive control group, low-dose, medium-dose and high-dose groups, with 8 rats in each group. Continuous intragastric administration (1 ml/100 g) for 60 days was performed respectively with ultrapure water, 0.4 g/L prednisone acetate, 2.0 g/L, 4.0 g/L, and 8.0 g/L lead acetate (PbAc). During the experiment, the general condition and weight changes of the rats were recorded in detail. After model establishment, biological samples of rats were collected. The levels of blood lead, serum calcium, phosphorus, tartrate-resistant acid phosphatase (TRAP) and bone alkaline phosphatase (BALP) in rats were determined. Additionally, micro-computed tomography (Micro-CT) was used to perform 3D reconstruction of the rat femurs and examine ultrastructural changes. One-way analysis of variance was used to compare multiple groups of data, and LSD or SNK methods were used for pairwise comparisons between groups.Results:During the experiment, there were no obvious abnormalities in feeding and drinking, behavioral activities, and fur color of rats in each group, and the body weight maintained normal and gentle growth. Compared with the blank control group, the levels of blood lead, serum calcium, phosphorus, TRAP and BALP in each dose group of PbAc were significantly increased ( P<0.05), while the femoral bone mineral density, bone volume/total volume and trabecular thickness were significantly decreased ( P<0.05). Compared with the blank control group, the trabecular separation of the femur in the high-dose group was significantly increased, and the trabecular number was significantly decreased ( P<0.05). Compared with the blank control group, the bone mass loss of the femur in each dose group of PbAc was severe in rats. Conclusion:PbAc can cause osteoporosis in rats, and osteoporosis assessment indicators such as bone resorption and bone formation markers in rats, femoral bone mineral density and its ultrastructure can all evaluate the success of model construction.

Objective:To explore the risk factors of enteral nutrition (EN) intolerance in patients with severe acute cerebral infarction (ACI) and analyze its impact on postoperative neurorehabilitation.Methods:A retrospective selection was made of 199 patients with severe ACI admitted to Zhoushan Hospital from January 2022 to May 2024. According to whether the patients developed feeding intolerance, they were divided into the feeding intolerance group (90 cases) and the feeding tolerance group (109 cases). The clinical data of the two groups were compared. Multivariate Logistic regression analysis was used to analyze the independent risk factors of feeding intolerance in patients with severe ACI, and the impact of EN intolerance on the National Institutes of Health Stroke Scale (NIHSS) score was analyzed.Results:The age, bed rest time, EN speed and Acute Physiology and Chronic Health EvaluationⅡ(APACHEⅡ) score in the feeding intolerance group were higher than those in the feeding tolerance group: (71.54 ± 11.44) years vs. (67.83 ± 13.82) years, (67.83 ± 13.82) d vs.(17.11 ± 8.41)d ,(61.50 ± 10.34) ml/h vs.(57.48 ± 7.95) ml/h,(22.68 ± 4.73) scores vs.(21.25 ± 5.12) scores; and the proportion of consciousness disorder and gastric tube use were higher than those in the feeding tolerance group: 56.7%(51/90) vs. 36.7%(40/109), 97.8%(88/90) vs. 89.0%(97/109); there were statistical differences ( P<0.05). The results of multivariate Logistic regression analysis indicated that old age, consciousness disorder, faster EN speed, and the use of gastric tubes were independent risk factors for EN intolerance in patients with severe ACI ( P<0.05). At 7 d after the start of EN, the total serum protein and hemoglobin in the feeding intolerance group were lower than those in the feeding tolerance group : (62.09 ± 6.07) g/L vs. (63.70 ± 5.34) g/L, (118.60 ± 17.01) g/L vs. (124.69 ± 18.51) g/L; and the scores of NIHSS was higher than that in the feeding tolerance group: (14.89 ± 7.68) scores vs. (12.40 ± 8.97) scores, there were statistical differences ( P<0.05). Conclusions:Old age, consciousness disorders, fast EN speed and the use of gastric tubes are risk factors for EN intolerance in severe ACI patients.

Objective To comparatively evaluate the diagnostic value of metagenomic next-generation sequencing(mNGS)versus conventional microbial culture in spinal infections.Methods A cross-section design was conducted on 82 consecutive patients with suspected spinal infections treated between February 2022 and January 2024 at Jiangbei Branch of First Affiliated Hospital of Army Medical University(Third Military Medical University).Microbiological culture,histopathological examination,and mNGS results from infected specimens were analyzed.Clinical diagnosis,primarily based on clinical manifestations,laboratory tests and radiologic features combined with medical history,was defined as the gold standard,and then the diagnostic performance,including sensitivity and specificity,were compared between mNGS and microbial culture.Results Among the 82 patients,definitive microbiological evidence was identified in 70 cases,and mNGS demonstrated a significantly higher detection rate than microbial culture(64 vs 36 cases,78.05％vs 43.9％,P<0.05).mNGS also obtained obviously higher sensitivity,accuracy,and negative predictive value(NPV),and notably lower positive predictive value(PPV)when compared to conventional microbial culture(all P<0.05).When stratified by infection type,mNGS obtained significantly higher sensitivity and accuracy compared to microbial culture in tuberculous spinal infections(P<0.05).For non-tuberculous spinal infections,mNGS also showed superior sensitivity to microbial culture(P<0.05).Conclusion In patients with spinal infections,mNGS demonstrates a significantly higher pathogen detection rate than conventional microbial culture.This technique can provide early and broad-spectrum pathogenic microbiological evidence for spinal infection.

Ultrasound technology has been applied in the biomedical field,particularly in drug delivery and cell processing.In this study,the effects of different ultrasound power levels(40 W to 100 W)and time durations(1 min,5 min,or 5 min discontinuously)on the morphology of human red blood cells(hRBCs)membranes were systematically investigated using cryo-electron tomography(Cryo-ET).The hRBCs membranes were firstly subjected to ultrasound at power levels of 40 W and 60 W for 5 min each.Cryo-ET observations revealed minimal morphological changes in the hRBCs membranes following the 40 W treatment,with the membrane structure remaining relatively intact and only minor undulations appearing on the membrane surface.These undulations might result from the mild mechanical stress induced by ultrasound,which was insufficient to disrupt the overall membrane structure.At power of 60 W,the hRBCs membranes largely preserved their structural integrity.When the ultrasonic power was increased to 80 W,the structural damage to the hRBCs membranes became more severe.Cryo-ET images showed irregular ruptures and larger pores on the membrane surface,indicating a significant compromise in membrane integrity.At ultrasound power of 100 W,the hRBCs membranes were completely disrupted,resulting in the formation of numerous membrane fragments,and a complete loss of membrane continuity.To further explore the effects of ultrasound duration on erythrocyte membrane morphology,the ultrasonic power was fixed at 100 W and the impacts of varying treatment durations(1 min,5 min,and intermittent ultrasound)on the membrane structure were systematically investigated.After 1 min of ultrasonic treatment,Cryo-ET images showed minimal changes in erythrocyte membrane morphology.Although some small pores and undulations appeared on the membrane surface,the overall structure remained relatively intact.As the ultrasound duration extended to 5 min,the degree of membrane damage increased significantly.Cryo-ET images revealed extensive rupture and detachment of the membrane,with continuity being severely compromised.As to treatment alternating 1 min of ultrasound with 1 min of rest,for a total of 5 min of ultrasound exposure,Cryo-ET observations showed the integrity of the membrane-cytoskeleton attachment remained.Under intermittent ultrasound treatment,although some pores and ruptures were observed on the membrane surface,the overall structure remained more intact compared to continuous ultrasonic treatment.This preservation might be due to the intermittent treatment providing buffer periods for the membrane,allowing partial recovery after mechanical stress,thereby reducing the cumulative damage caused by continuous ultrasound.This work provided experimental basis for further understanding of mechanism of ultrasound induced change of cell membrane and cytoskeleton.

A novel analytical method was developed in this study by combining online solid phase extraction with ultra performance liquid chromatography-tandem mass spectrometry(Online SPE-UPLC-MS/MS)for simultaneous determination of 50 kinds of steroid hormones in surface water.Specifically,after high-speed centrifugation of 4 mL water samples,the supernatant was directly injected into an Oasis HLB online SPE column for enrichment and purification.Subsequently,the target compounds were transferred to the analytical column via valve switching for separation and analysis.The chromatographic separation was performed on a Thermo Acclaim RSLC C18 column(100 mm×2.1 mm,2.2 μm),using a mobile phase composed of 5 mmol/L ammonium fluoride aqueous solution and acetonitrile.Mass spectrometric detection was conducted in positive ion mode,utilizing multiple reaction monitoring(MRM)with quantification achieved by the internal standard method.The method validation demonstrated that the limits of detection(LOD)for the 50 kinds of steroid hormones ranged from 0.02 to 0.50 ng/L,while the limits of quantification(LOQ)were between 0.08 and 1.67 ng/L.The average recoveries in surface water samples at spiked concentrations of 5,20 and 200 ng/L were between 74.1％and 119％,with relative standard deviations(RSDs)of 0.2％to 9.9％.This method was applied to analyze 11 surface water samples collected from sites surrounding a pharmaceutical and chemical industrial park.A total of 44 kinds of steroid hormones were detected,with concentrations ranging from 0.11 to 88.6 ng/L,revealing the presence of hormone contamination in the environmental waters surrounding industrial areas.Compared with the traditional offline SPE methods,the proposed online SPE technique significantly reduced sample volume requirements and pretreatment time,while minimizing the loss of target compounds during the pretreatment process.Moreover,compared to reported online SPE techniques,this method achieved high-throughput analysis of multiple classes of steroid hormones,with lower detection limits and higher recoveries.Overall,this method provided rapid sample preparation,high sensitivity,and excellent stability,making it suitable for the direct analysis of trace steroid hormones in surface water.