Search Results (603)

Background: Although most amputations caused by diabetes and peripheral artery disease (PAD) are preventable, current limb preservation efforts in the United States remain poorly understood. This study aims to identify key barriers and facilitators to limb preservation from the primary care provider (PCP) perspective. We plan to use the insights from this work to promote targeted intervention strategies. Methods: Using a mixed-methods design, an online 5–10 min survey was distributed to Oklahoma primary care providers who could elect to participate further in a semi-structured, audio-recorded interview. Descriptive analysis was used to summarize survey results. Interviews were transcribed and qualitatively analyzed using grounded theory. Donabedian’s structure, process, and outcome framework was used to categorize how each identified barrier and facilitator increases or reduces the risk of limb loss for at-risk patients at the practice level. Finally, we compared and contrasted survey and interview findings. Results: Thirty surveys were completed (approximately 14% response rate), and seven interviews were conducted with PCPs geographically dispersed across Oklahoma. Most clinicians reported in the survey that they see at-risk limbs at least once every 1–2 months (n = 29, 96.7%). Half of clinicians were satisfied or very satisfied with access to vascular surgery (n = 15, 50.0%), interventional specialists (n = 13, 43.3%), and endocrinologists (n = 12, 40.0%). Finally, survey respondents reported that social needs most often affecting their patients with a limb at risk of amputation include income, health education, transportation, and health insurance. Interviews confirmed PCPs frequently see at-risk limbs. We identified thematic barriers to limb preservation that included limited access to specialty care, limited PCP and patient amputation prevention education, and patient social struggles surrounding transportation, finances, and insurance. Patient advocates (community, clinical, or personal), affordable medications, and more time with patients were reported as facilitators in amputation prevention. Conclusions: Oklahoma PCPs frequently see at-risk feet, realize poor access to care, and desire structural change to support excellent preventive care in diabetes and PAD. Limb preservation in Oklahoma is contingent upon shifting from disempowerment to engagement that requires systemic reform, clinical innovation, and community engagement. We identified several intervention strategies, including increasing education for PCPs to empower them to initiate early prevention, improving early identification and preventive therapy for patients at risk for limb loss, and cultivating specialty care access via networking and policy change. Full article

This study presents an electro-thermal analysis of high-power lithium-ion battery modules for urban air mobility (UAM) applications, focusing on assessing the operational impact of installing a thermal barrier pad (TBP)—designed for thermal runaway delay—to ensure that the module maintains acceptable performance during normal operations. An integrated electro-thermal simulation model was developed and validated through single-cell experiments under step-load conditions, showing good agreement with measured voltage and temperature. In the baseline module without a TBP, higher discharge rates resulted in increased heat generation and cell temperatures, with approximately 42.5% of the electrical output dissipated as heat under the 5C condition. When the TBP was applied, the cooling performance of the heat sink decreased, leading to higher module temperatures and increased temperature differences between the cell and the heat sink, particularly as the TBP thickness increased. A simplified UAM flight scenario was simulated to evaluate temperature behavior throughout various operating phases. For the 1.5 mm TBP model, the maximum temperature (75.7 °C) remained within the design limit (80 °C). However, increasing the maximum take-off discharge rate to 6C or higher caused the module to reach its thermal limit or cut-off voltage before mission completion. These results indicate that TBP installation can be applied without unacceptable performance degradation under normal operation, provided that its thickness is optimized by considering cooling performance, thermal safety, and weight/volume constraints in UAM applications. Full article

This paper presents an advanced W-band bidirectional Power Amplifier–Low Noise Amplifier (PALNA) implemented using 130 nm SiGe BiCMOS technology. The proposed RF front-end eliminates the need for conventional transmit/receive (T/R) switches by employing a bidirectional architecture with a passive matching network. This approach minimizes area requirements and reduces signal losses. Post-layout simulation results demonstrate that the designed PALNA achieves a peak small-signal gain of 30 dB in Tx mode and 26 dB in Rx mode, with reverse isolation better than 40 dB. The 3 dB bandwidth spans from 94 to 106 GHz. In LNA mode, the design achieves a minimum noise figure of 6 dB at 100 GHz, remaining below 6.5 dB across the entire 3 dB bandwidth. In PA mode, the simulated saturated output power is 10.5 dBm, with a maximum power-added efficiency of 12% at 100 GHz. The chip size is 0.7 mm² including pads. It consumes 78 and 22 mW in the Tx and Rx modes, respectively. Full article

Accurately identifying fractures from X-ray images is crucial for timely and appropriate medical treatment. However, existing models suffer from problems of false localization and poor accuracy. Therefore, this research proposes a medical X-ray fracture detection model with precise localization based on the You Only Look Once version 11 nano (YOLOv11n) model. Firstly, a data augmentation technique combining random rotation, translation, flipping and content recognition padding is designed to expand the public dataset, alleviating the overfitting risk due to scarce medical imaging data. Secondly, a Bone-Multi-Scale Convolutional Attention (Bone-MSCA) module, designed by combining multi-directional convolution, deformable convolution, edge enhancement and channel attention, is introduced into the backbone network. It can capture fracture area features, explore multi-scale features and enhance attention to spatial details. Finally, the Focal mechanism is combined with Smoothed Intersection over Union (Focal-SIoU) as the loss function to enhance sensitivity to small fracture areas by adjusting sample weights and optimizing direction perception. Experimental results show that the improved model trained with the expanded dataset outperforms other mainstream single-object detection models. Compared with YOLOv11n, its detection accuracy, recall rate, F1-Score and mean Average Precision 50 increase by 4.33%, 0.92%, 2.52% and 1.24%, respectively, reaching 93.56%, 86.29%, 89.78% and 92.88%. Visualization of the results verifies its high accuracy and positioning ability in medical X-ray fracture detection. Full article

Face recognition is one of the most widely adopted biometric technologies, with applications in mobile devices, banking, and access control. However, its widespread use raises security concerns. One of the most common threats is presentation attacks (PAs), in which adversaries spoof the system using printed photos, videos, or masks. Developing effective Presentation Attack Detection (PAD) methods has become critical, yet generalizing to unseen Presentation Attack Instruments (PAIs) remains a major challenge. This is further complicated by the fact that most public PAD datasets are closed and limited in attack diversity and acquisition conditions. Standard evaluation protocols are typically based on intra- and inter-dataset setups, which may not reflect real-world variability. To address this, we propose analyzing presentation attacks using a novel metric, the Presentation Attack Similarity Index, which quantifies the similarity between different attacks. Based on this, we identify Presentation Attack Similarity Clusters, grouping attacks with high interchangeability. This approach offers deeper insight into PAI relationships, allowing for the strategic selection of representative attacks and the design of more balanced training datasets. Full article

This paper presents a 90–100 GHz wideband digital phase shifter with a fine resolution of 5.625°, implemented in a 0.13 μm SiGe BiCMOS process. A switch-type architecture with six cascaded units, including a novel 180° cell based on a broadband coupler, enables full 0–360° phase coverage while improving phase accuracy, bandwidth, and process robustness. Post-layout simulations demonstrate an insertion loss below 15.5 dB, an RMS phase error under 2.3°, and an RMS amplitude error better than 0.9 dB across the 90–100 GHz band. The total chip area, including test pads, is 0.39 mm², making the design compact and well suited for high-density phased-array applications. Full article

Complex deep hole parts are crucial for major equipment to achieve structural innovation and technological leapfrogging. With the continuous advancement of requirements for weight reduction, efficiency enhancement, and performance modification, the application of deep bottle hole parts has become increasingly widespread. Their structures are mainly characterized by complex interior profiles, variable diameters, large depth-to-diameter ratios, etc. However, the traditional vibration-damping tool boring process is prone to problems such as poor hole straightness and low cutting efficiency due to poor tool rigidity and difficult chip evacuation. For this reason, this research focuses on an internal chip evacuation tool system for deep bottle holes based on cutting morphology control. First, based on the structural characteristics of deep bottle hole components, a specialized tooling system with three guide pad supports and internal chip evacuation channels was designed. Subsequently, the tool’s chip evacuation channel was optimized using fluid simulation results from the tooling system, and the coupled relationship between chip morphology and chip evacuation efficiency was analyzed. Finally, a segmented and layered boring process scheme was proposed based on the component’s structural features. Through deep bottle hole-boring experiments, the surface roughness of the hole interior reached 0.9 µm, and eccentricity was reduced by 54.39%, confirming that the scheme effectively forms chip morphology into spiral curled chips and validating the feasibility and effectiveness of the tooling system. Full article

This study aimed to investigate the effect of antagonist static stretching applied between sets during resistance training on the number of repetitions of leg press exercise in young volleyball players. For this purpose, a total of 16 female active volleyball players (age 15.50 ± 0.52 years; height 167.25 ± 6.10; body mass 57.00 ± 5.98) participated voluntarily. The athletes participating in the study visited the laboratory five times. In the first session, anthropometric measurements were taken. In the second session, their 10 repetition maximums (RTs) were recorded, and in the third session, 10 control RTs were recorded. In the other two sessions, athletes were randomly assigned to two experimental protocol treatments in accordance with the crossover experimental design. In the traditional application, leg press exercise was performed as four sets with their own maximums and 2 min of passive rest between sets. In the experimental application, the participants performed four sets of leg press exercise with ten repetitions of their own maximums until concentric exhaustion, and static hamstring stretching was applied continuously for 30 s over 2 min between sets. All participants participated in both application protocols in different sessions. SPSS 20.0 package programed and GraphPad Prizm 8 graphics program were used for the analysis of all data. Data were analyzed at 0.05 significance level. In the findings obtained, Group* application interaction was found to be statistically significant according to the application and groups (F = 4.198, p = 0.016, η_p² = 0.219). In the leg press repetitions, statistical significance was found in favor of the experimental treatment in the third and fourth sets. This study shows that antagonist static stretching applied between sets positively affects resistance training performance by increasing the number of repetitions in leg press exercise in young female volleyball players. Full article

As MEMS design encounters growing challenges, particularly stiction between movable and stationary electrodes, dielectric charging, pull-in instability, and multi-valued response characteristics, the integration of dimple-equipped structures has emerged as a pivotal solution to mitigate these fundamental issues. Consequently, this study investigates the dynamic behavior of an electrostatically actuated double-clamped microbeam incorporating dimples and contact pads. While the dimples enhance the beam’s travel range, they may also induce an impact mode upon contact with the landing pads, leading to complex nonlinear dynamic phenomena. A reduced-order model was developed to numerically solve the governing equation of motion. The microbeam’s response was analyzed both with and without dimples using multiple analytical techniques, including bifurcation diagrams and discrete excitation procedures near the impacting regime. The findings demonstrate that the inclusion of dimples effectively suppresses stiction, pull-in instability, and multi-valued responses. The results indicate that upon contacting the landing pads, the beam exhibits pronounced nonlinear dynamic behaviors, manifesting as higher-period oscillations such as period-3, period-4 and period-5 and then fully developed chaotic attractors. Indeed, this specifically demonstrates the potential of using the dynamic transition from a steady-state to a chaotic response to build novel MEMS sensors. Full article

Natural playgrounds have garnered growing attention as supportive environments for children’s mental health. This study develops an analytical framework grounded in affordance theory and incorporates the Pleasure–Arousal–Dominance (PAD) model to examine the relationships between physical environmental features—and their combinations—in natural playgrounds and children’s emotional perceptions. Using the Yunhu Natural Playground in Fuzhou, China, as a case study, we selected seven typical behavior setting units. Environmental features were assessed through UAV imagery and on-site observations, while PAD-based visual questionnaires were employed to collect emotional responses from 159 children. By applying correlation analysis, random forest, and regression tree models, this study identified key environmental predictors of children’s emotional responses and revealed heterogeneous mechanisms across the three emotional dimensions. The results indicated that seasonal flowering/fruiting plants, accessible lawns, and structured play facilities were critical in supporting children’s pleasure, arousal, and dominance. Specifically, pleasure was primarily associated with sensory enjoyment and contextual aesthetics, arousal favored open grassy areas, and dominance was linked to environments with clear structure and manipulability. Based on these findings, this study proposes a spatial configuration strategy characterized by “nature as foundation, play encouraged, and structure clarified” to promote the positive development of children’s multidimensional emotional experiences. This research contributes empirical evidence on the role of physical environmental features in supporting children’s play behaviors and expands the theoretical understanding of the “emotional effects” of green spaces. While the findings are exploratory and context-specific, they emphasize the critical role of the sensory–behavioral–emotional chain in shaping children’s well-being and provide theoretical and practical guidance for the design of emotionally supportive, child-friendly, natural play environments in schools, parks, and residential areas. Full article

The growing digitization of healthcare has amplified concerns about the privacy and security of medical images, as conventional encryption methods often fail to provide sufficient protection. To address this gap, we propose a privacy-enhancing image encryption algorithm that integrates SHA-256 hashing, block-wise processing (16 × 16 with zero-padding), DNA encoding with XOR operations, and logistic map-driven key generation into a unified framework. This synergistic design balances efficiency and robustness by embedding data integrity verification, ensuring high sensitivity to initial conditions, and achieving strong diffusion through dynamic DNA rules. Experimental results confirm that the scheme achieves high NPCR (0.997), UACI (0.289), entropy (7.995), and PSNR (27.89 dB), outperforming comparable approaches while maintaining scalability to large image formats and robustness under compression (JPEG quality factors 90 and 70). These findings demonstrate that the proposed method offers an efficient and resilient solution for securing medical images, ensuring confidentiality, integrity, and practical applicability in real-world healthcare environments. Full article

Active vibration control designs for journal bearings have improved rotordynamic stability and led to advancements in adjustable bearing types that enable precise control of bearing geometry. In this study, optimized machine learning (ML) algorithms were modeled and implemented to accurately predict the static performance envelope of a four-pad active journal bearing with features of controlling the radial and tilt positions of pads in real time. ML models developed for the adjustable bearing system help predict its behavior as a function of three key input parameters such as the eccentricity ratio and radial and tilt positions of pads. Four supervised regression models, such as Random Forest Regression (RFR), Extreme Gradient Boosting (XGBoost), Light Gradient Boosting Machine (LightGBM), and a feedforward Artificial Neural Network (ANN), were chosen for their demonstrated ability to capture complex nonlinear patterns and their robustness against overfitting in such tribological applications. Hyperparameter tuning for each model was performed using the Optuna framework, which applies Bayesian optimization to efficiently determine the best parameter settings. The Optuna-optimized ensemble and neural network models were used to identify the optimal combinations of input variables that maximize the static performance envelope of the active bearing system with geometric adjustments. Full article

The active or adjustable journal bearings are designed with unique mechanisms to reduce the rotor-bearing system lateral vibrations by adjusting their damping and stiffness. The article provides a comprehensive review of the literature, outlining the structure and findings of studies on active bearings. Over the years, various kinds of adjustable bearing designs have been developed with unique operational mechanisms. Such bearing designs include adjustable pad sectors, externally adjustable pads, active oil injection through pad openings, and flexible deformable sleeves. These modifications enhance the turbine shaft line’s performance by increasing the system’s overall stability. The detailed review in this paper highlights the characteristics of bearings, along with the key advantages, limitations, and potential offered by active control across different bearing types. The efficiency of any rotor system can be greatly enhanced by optimally selecting the adjustable bearing parameters. These adjustable bearings have demonstrated a unique capability to modify the hydrodynamic operation within the bearing clearances. Experimental studies and simulation approaches were also utilized to optimize bearing geometries, lubrication regimes, and control mechanisms. The use of advanced controllers like PID, LQG, and Deep Q networks further refined the stability. The concluding section of the article explores potential avenues for the future development of active bearings. Full article

The development of adaptive and comfortable sports bras is essential for adolescents, who experience rapid changes in body morphology during growth. Traditional bras, often made with molded polyurethane bra pads, frequently fail to accommodate these variations, leading to discomfort and poor fit. This study investigates the design of a flexible-fit bra utilizing advanced knitting technology and bio-based materials, including organic cotton and renewable acetate, to enhance comfort and adaptability. The bra, crafted from bio-based yarns, offers stretchability, breathability, and fit, allowing it to adapt to various breast shapes and sizes. Such a bra design is particularly suitable for adolescents undergoing rapid growth. This study includes assessments of material properties and user feedback to evaluate the effectiveness of the design and identify areas for improvement. Positive results were reported from both material tests and subjective evaluations, confirming the effectiveness of the design. The seamless knitting minimizes irritation, while the inlay spacer fabric absorbs impact, and the pointelle structure improves moisture management. Adjustable components enhance adaptability and ensure a flexible fit. This study highlights the potential of knitted biomaterials for creating adaptive intimate apparel, offering a scalable solution for size-inclusive fashion. Full article

A lunar landing pad (LLP) represents essential initial infrastructure for establishing sustainable lunar settlements. This study investigates the feasibility of constructing LLPs through in situ resource utilization (ISRU), focusing on an innovative composite material comprising lunar regolith and the high-performance thermoplastic Polyether Ether Ketone (PEEK). The proposed manufacturing approach involves mechanically blending regolith with PEEK granules, compacting the mixture in a mold, and thermally processing it to induce polymer melting and binding. Experimental analysis indicates that a modest binder fraction (15 wt. % PEEK) yields a robust composite with a flexural strength of 14.6 MPa, although exhibiting inherently brittle characteristics. Compaction pressure emerges as a crucial factor influencing material performance. Utilizing these findings, hexagonal modular tiles were designed as the fundamental LLP elements, specifically engineered to optimize manufacturing simplicity, mechanical robustness, stackability for redundancy, and ease of replacement or repair. The tile geometry strategically mitigates brittleness-induced vulnerabilities by avoiding stress concentrations. Explicit finite element analyses validated tile performance under simulated lunar landing conditions corresponding to the European Large Logistic Lander specifications. Results demonstrated safe landing velocities between 0.1 and 0.7 m/s, governed by the binder content and compaction pressure. A clearly identified linear correlation between the binder fraction and permissible impact velocity enables predictive tailoring of the material composition, confirming the suitability and scalability of thermoplastic–regolith composites for future lunar infrastructure development. Full article