Search Results (3,281)

Objectives: This study aimed to investigate the associations between serum lipid biomarkers and pulse wave analysis (PWA) variables in patients at high and very high cardiovascular risk, with particular emphasis on age-related differences. Methods: Seventy-six patients at high or very high cardiovascular risk were enrolled and stratified into middle-aged (Group 1) and elderly (Group 2). All participants underwent PWA, and multiple serum lipid biomarkers were measured, including composite lipid indices. Results: In both age groups, PWA parameters showed significant correlations with serum lipid biomarkers. Systolic blood pressure (SBP) was an independent determinant of the lipid balance index (LBI), while pulse wave velocity (PWV) and SBP were independent determinants of the triglyceride–glucose (TyG) index. PWV correlated with age in both groups and was higher in Group 2 for comparable blood pressure values. In middle-aged patients, diastolic blood pressure (DBP) showed significant, independent associations with triglycerides and TyG, indicating a close link between peripheral vascular resistance and metabolic dysfunction in earlier stages of cardiovascular risk. In elderly patients, SBP and pulse pressure were predominantly associated with lipid-derived indices, reflecting the increasing contribution of large-artery stiffness and lipid-driven vascular remodeling with advancing age. Systematic Coronary Risk Estimation 2 (SCORE2) correlated significantly with PWV, the lipid index (LI), and the LBI. Conclusions: Serum lipid biomarkers and PWA-derived hemodynamic variables exhibit a significant, age-dependent interplay in patients with high and very high cardiovascular risk. These findings underscore the importance of age-specific evaluation of lipid–hemodynamic interactions to improve early identification and targeted management of high-risk individuals. Full article

This study presents a computational, simulation-based investigation of the dielectric response of human hand tissues, skin, fat, muscle, and bone to radiofrequency (RF) electromagnetic fields emitted by mobile devices. The widespread adoption of handheld devices and the deployment of fifth-generation (5G) networks, including millimetre-wave (mmWave) bands, have intensified concerns regarding localized human exposure to RF radiation, particularly in the hand, which serves as the primary interface during device operation. Using validated dielectric property datasets, numerical simulations were performed across the frequency range of 0.5–40 GHz, employing the Finite-Difference Time-Domain (FDTD) method to solve Maxwell’s equations, with analytical evaluations conducted in Maple-18. A heterogeneous multilayer hand phantom was developed, and simulations were conducted under controlled exposure conditions, including a transmitted power of 1 W, antenna gain of 2 dBi, and incident power density of 5 W/m², consistent with ICNIRP and NCC safety guidelines. Tissue responses were assessed over a temperature range of 10–40 °C to account for thermal variability. The results demonstrate strong frequency- and temperature-dependent behaviour of dielectric properties, intrinsic impedance, reflection coefficient, attenuation, and specific absorption rate (SAR). At lower frequencies (<1 GHz), RF energy penetrated more deeply with distributed absorption and relatively low SAR values, whereas higher frequencies (3–40 GHz) produced highly localized absorption in superficial tissues, particularly skin and muscle. Increasing temperature led to significant increases in permittivity, conductivity, and SAR, with up to a twofold enhancement observed between 10 °C and 40 °C. These findings confirm that 5G and mmWave exposures result in predominantly surface-confined energy deposition in hand tissues. The study provides a robust computational framework for evaluating hand device electromagnetic interactions and offers quantitative insights relevant to antenna design, exposure compliance assessment, and the development of evidence-based safety guidelines. Full article

As a ferrite material with excellent magnetic and dielectric properties, CoFe₂O₄ is in high demand for applications in areas such as wave absorption and magnetic storage. Effective regulation of its nanoscale morphology is central to improving application performance. Conventional synthesis methods often face challenges including poor particle dispersion and irregular morphology, which limit further optimization of material properties. In this study, a combined approach of microwave hydrothermal synthesis and annealing was employed to systematically investigate the effects of hydrothermal temperature, reaction time, and annealing parameters on the morphology and properties of CoFe₂O₄. The samples were characterized using X-ray diffraction, scanning electron microscopy, energy dispersive spectroscopy, and other techniques. Experimental results show that process parameters exert a notable influence on the crystallinity, particle dispersibility, magnetic and wave-absorbing properties of CoFe₂O₄: the sample prepared by microwave hydrothermal treatment at 75 °C for 30 min exhibits relatively better wave-absorbing performance, with a minimum reflection loss of less than −30 dB and an effective absorption bandwidth covering 8~16 GHz; the sample treated at 100 °C for 15 min shows a more balanced magnetic performance, with the saturation magnetization approaching 60 emu/g. The quantitative structure–property relationships of pure-phase CoFe₂O₄ across microwave hydrothermal and post-annealing processes, and achieve stable, reproducible performance enhancements under optimized mild conditions. These results supplement key experimental data for the low-temperature preparation of CoFe₂O₄ and establish a practical, energy-efficient parameter framework for future structural design and process optimization of this important magnetic material. Full article

Background: Load carriage is an essential part of the occupational work of many jobs, yet there is little research on the hemodynamic responses to load carriage. It is known that front load carriage elicits larger increases in arterial stiffness than load carried on the side of the body. However, the hemodynamic forward and reflected pulse wave responses to load carriage are unknown and could relate to cardiac risk. Methods: We compared responses to 30 s front load carriage between 45 females and 23 males, with pre- and post-carry hemodynamics assessed using pulse wave analysis. Results: We found increases (p < 0.001) in arterial stiffness (24.8% females; 32.4% males), forward pulse wave (5.8 mmHg females; 5.7 mmHg males), and reflected pulse wave (6.8 mmHg females; 9.9 mmHg males). Pre- and post-carriage forward and reflected pulse waves were lower in females (p < 0.05). Compared to males, females overall had more relationships between the change in vascular measurements and other variables. We found an inverse relationship between changes in myocardial supply–demand (SEVR) and changes in forward pulse wave in females (r = −0.37, p < 0.001) but not males. Also, a direct relationship between changes in SEVR and changes in aortic DBP (r = 0.30, p = 0.04) and changes in resting DBP (r = 0.35, p = 0.02) existed in females. Conclusions: The data suggest that sex-related differences in hemodynamic responses exist. Females may experience a larger drop in estimated myocardial supply–demand balance accompanied by lower diastolic filling. Employers should be aware of these inherent cardiac risks with load carriage in their female employees. Full article

Supercritical wings are widely used in large aircraft due to their excellent transonic performance, but their aerodynamic characteristics are highly sensitive to Reynolds number. To systematically study the influence of Reynolds number on the aerodynamic characteristics of a supercritical wing, cryogenic high Reynolds number pressure measurement tests were conducted in the European Transonic Wind Tunnel (ETW). A 1:17.87 scale wing-body combination model of a typical supercritical wing was employed. The Reynolds number was increased via the pressure increase and cooling technique, covering a test Reynolds number range from 2.3 × 10⁶ to 3.5 × 10⁷. Model deformation effects were isolated to obtain pressure data reflecting pure Reynolds number effects. The variation patterns of pressure distribution, lift characteristics, and pitching moment characteristics with Reynolds number were analyzed. The results indicate that, at lower speeds (Ma = 0.4 and 0.6), the supercritical wing is less affected by Reynolds number; the upper surface is more significantly influenced by Reynolds number than the lower surface; the Reynolds number effect primarily manifests in the transonic regime by delaying the onset position of the shock wave on the upper wing surface, thereby affecting aerodynamic force characteristics; several aerodynamic characteristic parameters such as ΔC_L, α₀, and C_m exhibit a linear relationship with the logarithm of Reynolds number. Experimental results obtained at low Reynolds numbers cannot be directly extrapolated to actual flight conditions, necessitating the consideration of Reynolds number effect in the aerodynamic design optimization of large aircraft. Full article

With the deepening of fifth-generation mobile communication technology (5G) commercialization and the surge in demand for intelligent connectivity of all things, the sixth-generation mobile communication technology (6G) has entered a phase of technological breakthroughs. The innovation in antenna design will determine the upper limits of 6G communication. This paper systematically reviews the research progress on antenna technology for 6G communications, focusing on operating frequency bands, antenna structure design, and materials and packaging technologies. The development of 6G communication technology drives antenna research toward higher-frequency bands, with the current research focus extending from the millimeter wave (mmWave) band to the terahertz (THz) band. Compared to the traditional mmWave band, the THz band shows significant advantages in performance indicators. At the antenna structure level, its development trend is mainly reflected in the following three aspects: size miniaturization, scale expansion and distributed deployment, and expansion of frequency bands and functions. New materials and advanced packaging have become key enabling technologies: materials with low-loss characteristics and tunable surface conductivity have become research focuses. Meanwhile, advanced packaging processes achieve miniaturization and high-performance integration of antenna systems. This review aims to provide a systematic technical reference for the research and engineering development of next-generation 6G antennas. Full article

In this work, we further investigate the surface wave attenuation performance of elastic metasurfaces composed of in-filled pipes in a layered half-space, focusing on the dispersion relations and transmission properties. Particularly, both Rayleigh waves and Love waves are considered. The introduction of soil layers will reduce the width of attenuation zones. Additionally, transmission simulations reveal complex propagation patterns for elastic metasurfaces in a layered half-space, including wave reflection, wave resonance, and higher-order wave modes, which will hinder the penetration of converted shear waves into the half-space. In contrast, in reference cases, only surface-shear wave mode conversion is observed. Moreover, the attenuation performance of elastic metasurfaces is also diminished in layered soils in the frequency domain, and a nonuniform displacement distribution behind the elastic metasurface is also found. Last but not least, the feasibility of elastic metasurfaces to train-induced ground-borne vibration mitigation is numerically verified in the time domain. Although the performance of elastic metasurfaces in layered soils is inferior to that in homogeneous soils, they are better than traditional trenches within the main frequency range. Snapshots from the transient simulation clearly show the evolution of wave fields, reinforcing the observed key findings. Due to excellent surface-wave-attenuation performance and ease of realization, these novel elastic metasurfaces hold great potential in ambient vibration mitigation. Full article

This study investigates the temporal and spatial variations in sea level anomaly (SLA) and sea surface wind in the East China Sea (ECS) from 1993 to 2021 using AVISO altimetry data and ERA5 reanalysis wind data. Empirical Orthogonal Function (EOF) and trend analyses were applied to identify dominant modes and long-term changes. Results reveal pronounced seasonal SLA variability, with lower levels in winter/spring and higher levels in summer/autumn, strongly modulated by monsoon winds. The first EOF mode of SLA accounted for 52.73% of variance, showing basin-coherent seasonal fluctuations, while the second mode (7.79%) reflected contrasts between coastal and Kuroshio-influenced regions. The ECS experienced an average sea level rise of 3.77 mm/year, exceeding 6 mm/year along the Jiangsu and Zhejiang–Fujian coasts. Sea surface wind stress variability was greatest in the northern Taiwan Strait and southwest of the Ryukyu Islands, but decreased along the Zhejiang coast. Sea level anomalies (SLAs) in the East China Sea exhibit clear multi-scale coupling with the wind field. The seasonal SLA variability in the East China Sea is jointly modulated by local Ekman forcing due to wind stress, while also being potentially linked to the Kuroshio and open-ocean Rossby waves. These findings underscore the role of wind forcing in regional sea level changes and provide insight for coastal management under climate change. Full article

Although windows are known to modulate occupant well-being, the specific capacity of window dimensions to alleviate stress requires deeper empirical validation. To address this, we evaluated 36 young, healthy subjects (aged 20–27) within a virtual office configured with four window-to-wall ratios (WWR: 0%, 25%, 50%, and 75%). Stress levels were quantified by integrating subjective evaluations with EEG time–frequency domains and microstate transitions. The results demonstrated that windowed conditions consistently elevated subjective comfort ratings and α-wave activity, reflecting enhanced psychological relaxation. Notably, measured brain activity exhibited a peak at 0% WWR and a global minimum at 50% WWR, suggesting a potential physiological threshold for maximum relaxation within the tested demographic. Subsequent microstate analysis confirmed that windowed environments extended the duration of states B (visual processing), C (saliency network), and D (attention orientation), alongside increased transition shifts from state A to B and from state B to C. Utilizing these extracted physiological biomarkers, a developed neural network model predicted human comfort with 78.79% accuracy. Ultimately, these preliminary findings indicate that optimized window scaling can measurably mitigate urban stress, providing a data-driven theoretical framework for architectural design. Full article

Background/Objectives: Shear wave elastography (SWE) has emerged as a quantitative imaging technique for assessing muscle mechanical properties and has been increasingly applied to post-stroke spasticity. However, the clinical validity of SWE relative to established clinical spasticity scales and the influence of assessment protocols remain incompletely understood. This systematic review and meta-analysis aimed to evaluate the clinical validity of SWE for post-stroke spasticity and to identify clinically relevant methodological moderators. Methods: A systematic literature search was conducted in PubMed, Cochrane Library, CINAHL, and Web of Science to identify studies reporting correlations between SWE measures and clinical spasticity scales in individuals with stroke. Random-effects meta-analyses were performed using robust variance estimation to account for dependent effect sizes within studies. Prespecified subgroup and meta-regression analyses examined potential moderators, including clinical scale, muscle position during assessment, output metric, limb segment, and stroke chronicity. Results: Ten studies involving 303 participants contributed 38 correlation estimates. The pooled correlation between SWE and clinical spasticity scales was moderate (r = 0.42, 95% CI 0.34–0.49). SWE demonstrated significantly stronger correlations with the Modified Tardieu Scale than with the Modified Ashworth Scale. Measurements obtained in stretched muscle positions showed higher validity than those obtained at rest. Other examined moderators were not statistically significant. No evidence of publication bias was detected. Conclusions: SWE shows a moderate association with clinician-rated spasticity scales and appears to reflect the mechanical consequences of post-stroke spasticity. Associations were influenced by scale selection and measurement position. These findings support protocol-informed integration of SWE as a quantitative adjunct for assessing passive muscle stiffness rather than as a replacement for established clinical scales. Full article

miRNA 183 is part of the miRNA-183/96/182 cluster, which is known to play a decisive role in fine-tuning the activity of gene expression in sensory systems, particularly in the retina. Although miR-183 is essential for retinal gene expression in mammals, the contributions of miR-183 to mRNA expression and photoreceptor development and function in other classes of animals have not been fully elucidated. Danio rerio have a diverse photoreceptor system, with cone photoreceptors sensitive to red, green, blue and ultraviolet (UV) light. We generated knockout zebrafish by deleting the whole seed sequence of miR-183. RNAscope results show no expression of mature miR-183 and decreased expression of miR-182 in both dorsal and ventral KO retinas. The number of UV and blue photoreceptors decreased, and the photoreceptors showed shortening or loss of their outer segments. In the absence of miR-183, the transcription levels of phototransduction genes were altered differentially at 3 and 12 months of age. Finally, photoreceptor-only electroretinogram (PIII) signals showed attenuated amplitudes of red and green-sensitive photoreceptor subtypes while the b-wave amplitudes reflecting second order retinal neuron activity, were decreased in response to the UV-, blue-, and red-stimulating wavelengths. These results reveal a novel microRNA regulatory network in teleost fish and indicate that miR-183 plays a facilitative role in retinal development and function, especially for short-wavelength-sensitive photoreceptor subtypes. Full article

Micro-defects, such as ink spots, scratches, and sintering formed during the screen printing process of photovoltaic cells, significantly impair module performance. Traditional machine vision methods exhibit limited detection efficiency and high false-positive and missed-detection rates, while existing deep learning algorithms struggle to achieve accurate and adaptive detection of small-target defects and background similar defects in complex industrial environments. This study proposes an enhanced defect detection methodology based on an improved YOLOv8 algorithm. A multi-focus image acquisition platform using primary and auxiliary CCDs was independently developed, integrating a high-frame-rate industrial camera and a high-resolution electron microscope, with an LED ring light employed to suppress reflections, thereby establishing a high-quality dataset covering three defect categories. The algorithm was optimized through multiple dimensions: the RepNCSPELAN4 module was incorporated into the backbone network to improve multi-scale feature fusion, and a novel wavelet transform-based WaveConv module was designed to replace traditional downsampling, thereby better preserving defect edges and texture details. The neck network integrates a lightweight shuffle attention mechanism and a new detail enhancement module to strengthen critical features while controlling model complexity. Additionally, a dedicated auxiliary detection head was added for spotting tiny ink dots. Experimental results demonstrate a marked improvement in performance: on the custom dataset, the improved model achieves a stable mean average precision of approximately 92%. Specifically, ink spot detection reached a precision of 84.9% and recall of 77.7%, effectively reducing missed small-target defects; sintering defect detection attained 98.9% precision and 100% recall, addressing previous misclassifications due to background similarity; and scratch detection precision improved to 92.2%. Visual comparisons confirm that the enhanced model effectively overcomes the limitations of the original approach. By constructing a specialized dataset and implementing targeted, coordinated optimizations to the YOLOv8 architecture, this study significantly enhances the accuracy and robustness of screen-printing defect detection in photovoltaic cells, providing an effective solution for real-time online quality inspection in smart manufacturing lines. Full article

Type 2 diabetes mellitus and prediabetes often develop silently and may remain undiagnosed for years. This is particularly relevant in regions where laboratory-based screening is not always readily accessible. Against this background, the present work explores whether multilead electrocardiography can provide physiologically meaningful markers potentially associated with disturbances in glucose metabolism. We developed and tested an upgraded wearable 12-lead ECG system capable of synchronized multichannel recording under controlled conditions. ECG signals were acquired in sitting and standing positions, with a sampling frequency of 500 Hz and a recording duration of one minute per posture. The hardware architecture included a high resolution analog front-end and wireless data transmission; the accompanying software provided acquisition control, preprocessing, visualization, and data storage within a unified framework. Signal processing focused on the extraction of rhythm-related and morphological parameters, with particular attention to ventricular repolarization indices. QT interval, heart rate–corrected QT (QTc), and QT dispersion (QTd) were calculated across leads, as these parameters are known to reflect heterogeneity of repolarization and autonomic influences on myocardial electrophysiology. The analysis was structured to ensure reproducible boundary detection and systematic feature formation rather than isolated parameter measurement. The study had a pilot character and included a limited and unbalanced sample (healthy n = 10; prediabetes n = 1; T2DM n = 1). For this reason, the results are presented descriptively and should be regarded as preliminary observations. In representative cases, differences in QT-related indices were noted between categories of glycemic status; however, the potential influence of age, sex, and other confounders cannot be excluded. A pilot expert comparison of T-wave end detection demonstrated close agreement between the automated algorithm and cardiologist assessment (mean Δ$T_{end}$ approximately −1 to −2 ms; MAE 10–24 ms). Diagnostic performance metrics such as ROC/AUC, sensitivity, and specificity were not calculated at this stage, as validation in a larger cohort with biochemical confirmation (HbA1c, OGTT) is required. The study demonstrates the technical feasibility of combining synchronized 12-lead wearable acquisition with structured multilead repolarization analysis. The proposed system should therefore be considered a research platform intended to support further clinical validation and methodological development rather than a finished screening solution. Full article

Typhoon avoidance is critical for ship maneuvering safety under extreme meteo-ocean conditions. This study proposes a data-driven framework that converts AIS trajectories into interpretable course deviation and speed change responses for navigational decision support. After AIS cleaning, temporal resampling, and matching with gridded wind, wave, and current fields, rule-based sliding-window and regression procedures, informed by experienced captains and company staff, automatically generate proxy labels for deviation and speed reduction. Samples are stratified by vessel size to reflect differences in inertia and maneuverability, and XGBoost classifiers are trained with simple resampling to mitigate class imbalance. The framework is demonstrated on a single-event case study of Typhoon Yagi in the South China Sea, covering 8609 vessels and reconstructed sailing fragments. On the test set, the deviation model achieves 89.8% accuracy and high recall for deviation cases, while the speed change model reaches 82% balanced accuracy under the proxy-label setting. Results suggest a scale-dependent response: smaller vessels exhibit more frequent course deviation, whereas larger vessels more often reduce speed under severe wind-wave loading. The framework offers a proof-of-concept approach to derive behavior-based indicators from AIS and environmental data and may support situational assessment under adverse weather. Full article

A transient numerical framework incorporating dynamic mesh techniques was developed to simulate the launch process. On this basis, a thermal–fluid–structural multi-physics coupling paradigm was proposed to interpret the evolution of the flow field and the associated load response throughout the entire firing sequence. The results show that flow development follows a multi-stage dynamic pattern, comprising gas-impact filling, gap-jet formation, and subsequent free-jet expansion. A pronounced spatially heterogeneous phase lag was observed in the pressure–Mach number response. This phenomenon arises from a mismatch among the characteristic time scales of pressure-wave propagation, flow inertia, and shock–boundary-layer interaction. Quantitative analysis further indicates that the spatial superposition of high-temperature zones, high-Mach regions, and elevated-pressure areas activates a thermal–fluid–structural positive-feedback loop that drives the local peak temperature to approximately 2.5 × 10³ K. The temperature response lags behind the pressure maximum by approximately 30–50 ms, reflecting the governing time scale of thermal inertia. In addition, vortical structures near the tube base account for nearly 15% of the total thrust. These findings provide a theoretical foundation for predicting transient peak loads in concentric cylindrical systems and for optimizing instantaneous thermal protection strategies. Full article