Search Results (9,665)

Finger fractures are common and potentially disabling. Certain complex injuries, particularly with small fragments and/or open wounds, are not manageable with conventional orthopedic hardware. We created 3D-printed finger fracture fixators using polylactic acid (PLA) and polyethylene terephthalate glycol (PETG). We tested flexion stiffness and lateral stiffness, before and after sterilization for surgical use, and compared them against standard 316L surgical stainless-steel (SSS) wires. Because PLA and PETG are compromised at high temperatures, these were sterilized using hydrogen peroxide gas plasma, while the SSS wires were autoclaved. The PLA fixators demonstrated greater flexion stiffness, and equivalent lateral stiffness, to the SSS wires, both before and after sterilization. The PETG fixators demonstrated inferior flexion stiffness and lateral stiffness to the SSS wires, and these properties worsened with sterilization. The PLA fixator was then applied to a cadaveric hand in static and dynamic configurations, and demonstrated excellent radiolucency for visualization of bone alignment and healing. This novel PLA device secures numerous surgical stainless-steel wires, maintains greater flexion stiffness and equivalent lateral stiffness compared to the wires even after sterilization, allows for static and dynamic fixation with compact, lightweight, and modular radiolucent components, and is both low-cost and customizable on demand, which may benefit under-resourced communities. Full article

The exchange bias (EB) effect is widely used for stabilizing reference magnetic layers in traditional spintronic devices, yet the EB strength strongly depends on the interfacial quality. Van der Waals antiferromagnets provide an ideal physical platform to study the interfacial magnetic properties for device design in the 2D limit. Herein, we construct CrSBr/Fe₃GeTe₂ heterostructures and investigate the interfacial coupling via first-principles calculations. The results reveal that robust EB coupling in the heterostructure breaks the intrinsic in-plane magnetic limitation of CrSBr, inducing a stable tilted magnetic structure with magnetic moments tilting toward the out-of-plane direction. Such EB-driven magnetic reconstruction dramatically boosts the perpendicular magnetic anisotropy energy to ~6.5 meV/Cr and increases the AFM-FM energy difference to 1.97 meV/f.u. from 0.32 meV/f.u., achieving simultaneous enhancement of magnetic anisotropy and thermodynamic stability. The transport simulations of the CrSBr/Fe₃GeTe₂-based magnetic tunnel junction demonstrate that ~65% TMR can be achieved with the use of such an EB-pinned reference layer. This work clarifies the EB modulation mechanism in 2D CrSBr/Fe₃GeTe₂ heterostructures and provides a reliable theoretical basis for the design of high-performance CrSBr-based reference layers in spintronic devices. Full article

With the rapid advancement of terahertz technology, electromagnetic interference has become a critical issue that compromises device performance, creating an urgent demand for high-performance terahertz absorbers. Three-dimensional (3D) printing, characterized by flexible structural design, monolithic fabrication, and mold-free processing, has emerged as a promising technique for producing terahertz absorbers. In this work, inspired by the structural and functional characteristics of deep-sea sponges, we propose a bioinspired absorber design that integrates a porous topology with 3D printing. By optimizing the rotation angle and the hollowed array, the absorber establishes multiple internal reflection paths, which, combined with the structural matrix and the graphene conductive coating, enable highly efficient dissipation of electromagnetic energy. Experimental results show that the fabricated sample achieves an absorptivity exceeding 99% over the 0.5–2.0 THz frequency range, while also exhibiting wide-angle absorption and polarization-insensitive performance. The influence of pore size and graphene concentration on the absorption properties is systematically revealed. This work further enhances the performance of 3D-printed terahertz absorbers and provides a novel technical pathway for the design and fabrication of high-performance terahertz absorbers. Full article

Short-term GPU utilization forecasts are useful for scheduling, resource allocation, and capacity planning, but production traces are rarely smooth. They contain spikes, regime changes, idle periods, and incomplete observations. We study this problem on the MIT Supercloud Dataset using a direct, horizon-specific forecasting setup. After resampling the telemetry to 1 min intervals, the neural models are trained on min–max-normalized data and evaluated on the original 0–100% utilization scale after inverse transformation. Persistence and rolling mean predictors are added as non-trainable baselines and are evaluated on the same eligible targets as the neural models. Five sequence models—1D-CNN, GRU, FC-LSTM, Liquid Time-Constant Network (LTC), and Transformer—are compared at 1 min, 10 min, and 1 h horizons. To avoid a gross capacity imbalance, the primary model widths are chosen in a comparable range of approximately 55,000 trainable parameters. This controls the trainable model size only; the architectures still differ in computation, memory access, and optimization behavior. Besides the overall error, the experiments examine high-load periods, abrupt changes, and a 20% random zero-masking condition. Among the five neural models, FC-LSTM gives the lowest MAE and RMSE at the 1 min horizon. The persistence baseline reaches an MAE of 3.92 at this horizon, compared with 3.55 for FC-LSTM, corresponding to a 9.4% lower MAE for FC-LSTM. At 1 h, among the neural models, LTC has the lowest mean RMSE, while FC-LSTM retains the lowest MAE and WAPE. Paired GPU device-level comparisons indicate that the larger improvements over simple baselines are more robust than the small numerical gaps among the strongest neural models. The zero-masking robustness protocol is expanded to five masking seeds and all five primary neural models. Taken together, the results show that the preferred model changes with both the forecast horizon and error criterion. Full article

Polymer-based three-dimensional (3D) printing has evolved from a prototyping approach toward a manufacturing strategy with emerging clinical relevance for individualized dosage forms, local drug depots, microneedle systems, microfluidic cartridges, biosensor housings and integrated theranostic platforms. Its value arises from the simultaneous control of polymer chemistry, device architecture and process history: infill, porosity, shell thickness, crosslink density, swelling, degradation and surface chemistry can be used as design variables rather than incidental manufacturing outcomes. This review critically synthesizes recent progress in polymer-enabled additive manufacturing for drug delivery and diagnostic applications, with emphasis on thermoplastic and biodegradable polymers, hydrogels, photopolymers, elastomers, conductive composites, stimuli-responsive networks and bioinks. Fused deposition modelling, hot-melt extrusion, semi-solid extrusion, vat photopolymerization, two-photon polymerization, selective laser sintering, binder jetting and inkjet/aerosol jet approaches are compared in relation to drug stability, diagnostic compatibility, feature resolution, scalability and regulatory risk. Particular attention is given to geometry-controlled release, multi-drug printlets, microneedles, implants, scaffold-based local therapy, microfluidic diagnostics, electrochemical biosensors and wearable or closed-loop systems. Translation is discussed through quality-by-design, critical material attributes, critical process parameters, process analytical technology, extractables/leachables, sterilization, point-of-care manufacturing, data integrity and clinical evidence requirements. Future advances should connect polymer–process–property relationships with clinically meaningful use cases, verified quality attributes and realistic regulatory pathways. Full article

In vitro neurovascular unit (NVU) models are essential for reproducing blood–brain barrier (BBB) transport and neurovascular cell interactions. However, the literature remains fragmented: biomaterial chemistry, fabrication parameters and organ-on-a-chip architecture are commonly evaluated in isolation, while inconsistent reporting of matrix properties, processing history, cell source, flow and barrier readouts prevents head-to-head comparison and the extraction of transferable design rules. To address this gap, this review integrates biomaterials, manufacturing technologies and organ-on-a-chip engineering within a unified material–process–structure–function framework. We translate endothelial junctions, basement-membrane components and perivascular cells into experimentally actionable material requirements; compare natural, synthetic, semisynthetic and decellularized extracellular-matrix hydrogels; and examine crosslinking, peptide functionalization, stimuli responsiveness, composite-network formation and preparation methods. Findings from Transwell, microfluidic, tubular, self-assembled and 3D-bioprinted BBB systems are used to relate matrix stiffness, degradability, ligand density, permeability, device-body material and fabrication route to barrier maturation, analytical access and reproducibility. By defining matched controls and minimum reporting requirements for chemistry, mechanics, transport and processing, this review provides a practical basis for next-generation BBB models that can improve permeability and efficacy screening in drug discovery, reproduce disease- and patient-specific barrier dysfunction, and support individualized response testing with iPSC- or patient-derived cells. Full article

Terahertz (THz) metasurfaces have drawn considerable research interest, owing to their compelling potential in sensing, imaging, and wireless communication. However, most existing designs are constrained to a single predefined function, severely hindering their practical applicability in dynamic or multifunctional scenarios. Herein, we present a reconfigurable THz metasurface that enables on-demand functional transformation by harnessing the phase transition characteristics of vanadium dioxide (VO₂). The designed unit cell adopts a six-layer stacked configuration, sequentially comprising a VO₂ square ring, a first polyimide (PI) dielectric spacer, an elliptical gold patch, an intermediate VO₂ thin film, a second PI dielectric spacer, and a gold ground plane. When VO₂ is in its metallic phase, the metasurface operates as a metal–insulator–metal (MIM) absorber, achieving over 90% absorption in the frequency range of 1.01–1.91 THz. In the insulating state, it acts as a polarization converter, enabling efficient linear-to-circular polarization conversion (PC) with an axial ratio (AR) below 3 dB from 1.82 to 2.21 THz under linearly polarized (LP) incidence. Moreover, the metasurface exhibits robust performance under varying incident angles and different polarization conditions. Collectively, this design offers a flexible and reconfigurable platform for advanced THz devices, laying a solid foundation for THz communication, intelligent sensing, and imaging systems. Full article

Although additive manufacturing enables cost-effective surgical training models, variation in materials and printing parameters limits standardization. This study combined biomechanical testing and user evaluation to identify fused deposition modeling (FDM) settings for osteotomy simulation. Porcine ribs and three-dimensional (3D)-printed models were compared using three-point bending tests. Subsequently, 32 participants performed osteotomies using an ultrasonic device, a Lindemann bur, and a reciprocating saw. Haptic feedback was assessed by questionnaire, while surface artifacts were evaluated by two blinded evaluators. With 25% gyroid infill and two outer layers, maximum bending forces ranged from 322.9 to 552.1 N across the printed materials, compared with 604.9 N for the porcine ribs, with polylactic acid (PLA) showing the closest approximation. Polycarbonate (PC) achieved the highest haptic rating (6.7 ± 1.8), followed by acrylonitrile styrene acrylate (ASA), polyethylene terephthalate glycol (PETG), and PLA, with a significant difference between PC and PLA (p = 0.029). The reciprocating saw received the highest ratings across all criteria. Surface artifacts differed between materials (p < 0.001), with PETG and PLA showing more melting and fraying, and ASA and PC more stringing. No significant differences were observed between students and doctors. Overall, PLA most closely approximated the reference maximum bending force, whereas PC and ASA achieved the highest perceived tactile realism. Full article

Reversible Solid Oxide Cells (rSOCs) are highly efficient energy conversion systems for power generation in fuel cell mode (SOFC) and energy storage in electrolysis mode (SOEC). These devices are typically manufactured through multi-step processing routes based on conventional functional ceramic fabrication techniques, such as tape-casting, extrusion, screen-printing and spraying. In this work, an alternative mold-casting approach is proposed for the fabrication of planar electrolyte-supported rSOCs. Electrolytes made of 8 mol% yttria-stabilized zirconia (YSZ) were prepared via an aqueous gel-casting process using agarose as the gelling agent. The casting molds were fabricated by 3D printing with polylactic acid (PLA) filament. Dense electrolytes with well-controlled geometries were successfully obtained. Complete cells were produced using porous Ni–YSZ as a fuel electrode and porous lanthanum strontium manganite–YSZ. The cells were microstructurally characterized, and their electrochemical performance was evaluated under both SOFC and SOEC operating conditions at 800–900 °C. At 900 °C, the cell achieved a peak power density of 220 mW cm⁻² in fuel cell mode and an injected current density of 340 mA cm⁻² at 1.3 V in electrolysis mode. Mid-term galvanostatic testing in SOFC mode at 850 °C for 400 h demonstrated good durability and structural stability of the fabricated cells. After the initial stabilization period, the cell exhibited a low degradation rate of 3 mV kh⁻¹. Full article

This study presents a sensor-fused field investigation and simulation-based analysis of four horizontal and vertical traffic-calming devices—two raised speed tables, a speed hump, and a raised crosswalk—installed along a 5250-ft two-lane residential collector in Nashville, TN, USA. A dual-sensor architecture combining a Miovision Scout video-based vehicle counter and WAAS/EGNOS-augmented GPS probe-vehicle logging (5 m 3-D RMS horizontal accuracy, 1 Hz sampling) was used to reconstruct 30 quality-controlled free-flow vehicle trajectories and 12-h per-lane volume counts. A spatial kinematic transform (a = v·dv/dx) was applied to extract device-specific approach-deceleration and post-device recovery-acceleration rates, and a three-parameter log-logistic cumulative-distribution function was fitted to the field-observed desired-speed percentiles (root-mean-square error below 0.043 for both speed-table devices). The camera- and GPS-derived observations were used to calibrate and statistically validate a PTV VISSIM microsimulation replica of the corridor, achieving a mean-speed calibration error of 0.71% or better at every device, a GEH statistic below 1.5 at all four analysis turning movements, and independent travel-time validation errors of 5.7–12.1%, within the accepted 15% threshold. The validated model was then used to reconstruct device- and spacing-specific May–Keller macroscopic speed–density–flow relationships, calibrated against simulated capacities of 650–775 vehicles per hour per lane at 350-, 700-, and 1050-ft device spacing. Results show capacity reductions of 20–33% relative to free-flow conditions and yield kinematically derived maximum recommended spacings of 265–630 ft to maintain crossing speeds at or below 15 mph, depending on device geometry. The findings demonstrate a reproducible, low-cost sensor-fusion workflow for quantifying the safety–capacity trade-off of traffic-calming corridors and for informing the design of sensor-in-the-loop adaptive-calming infrastructure. Full article

In this work, Cu₂CoSnS₄ (CCTS) thin films were deposited on glass substrates by thermal evaporation and investigated for photovoltaic applications. The influence of substrate temperature, varied from 25 °C to 200 °C, on the structural, morphological, and optical properties of the films was experimentally studied using X-ray diffraction (XRD), scanning electron microscopy (SEM), and photoluminescence (PL) measurements. XRD analysis confirmed the formation of crystalline CCTS with a stannite structure and a preferential orientation along the (112) plane. SEM observations revealed rough and non-uniform surfaces accompanied by an increase in grain size with increasing substrate temperature. Room-temperature PL measurements indicated a band-gap energy of approximately 1.3 eV, suitable for photovoltaic applications, and confirmed the presence of secondary phases in the p-type stannite CCTS films. Despite the promising photovoltaic properties of CCTS, numerical studies on CCTS-based solar cells remain scarce in the literature. In this context, a numerical study of the CCTS-based solar structure grown on glass was also performed using SCAPS-1D, showing good agreement with experimental photovoltaic results and validating the simulation model. Replacing the glass substrate with silicon improved the device efficiency to 5.77%. Further optimization of the series and shunt resistances significantly enhanced the photovoltaic performance, achieving a power conversion efficiency of 16.77%, with FF = 52.94%, V_oc = 0.89 V and J_sc = 35.19 mA/cm². Full article

Flexible pressure sensors serve as core sensing components for wearable health monitoring systems, electronic skins for soft robots, and flexible human–machine interaction devices. Benefiting from the interfacial electric double-layer polarization effect, iontronic sensing delivers far higher pressure response sensitivity than conventional parallel-plate capacitive sensors, endowing it with distinctive advantages in the detection of weak physiological signals. Nevertheless, current dense ionic thin-film dielectric layers suffer from limited deformation space under compression and poor low-pressure sensing capability. Mainstream high-precision micropillar arrays are fabricated via photolithography, 3D printing, and metal etching molds, which require costly equipment and complicated fabrication procedures, making large-area mass production unfeasible. Random frosted concave-convex microstructures feature disordered dimensions, leading to severe device hysteresis and narrow linear ranges, which fail to achieve ultrahigh sensitivity alongside a wide pressure detection range simultaneously. To address the aforementioned multiple bottlenecks, this paper proposes a low-cost resin template replication process to fabricate TPU-based ionic thin-film dielectric layers with ordered micropillar array microstructures. Combined with inkjet-printed silver conductive PI flexible electrodes, an iontronic flexible pressure sensor with a sandwich layered structure is constructed. Multi-dimensional investigations including microscopic morphology characterization, electromechanical sensing performance calibration, and human wearable application tests are systematically implemented to thoroughly elucidate the synergistic enhancement mechanism of the arrayed micropillars. Test results demonstrate that the effective pressure detection range of the sensor spans 0–1038 kPa, accommodating ultra-low pressures such as pulse signals as well as medium-to-high-pressure loads including joint bending. The sensitivity reaches 23.27 kPa⁻¹ within the low-pressure range of 0–200 kPa and remains stable at 3.52 kPa⁻¹ in the high-pressure range of 200–1038 kPa, with piecewise linear fitting correlation coefficients of 0.93 and 0.96 respectively. Both the response time and recovery time of the device are 40 ms, and the hysteresis error throughout the loading-unloading cycle is merely 2.62%. After 20,000 consecutive cyclic loading-unloading tests, the peak capacitance output only decays by 5.1%, verifying outstanding mechanical fatigue resistance and electrical stability. Validations in multi-scenario applications prove that the sensor can accurately capture human physiological and motion signals including radial artery pulses, laryngeal deformation induced by multi-syllable vocalization, and multi-angle bending of fingers and elbow joints, suitable for home-based health monitoring, quantitative rehabilitation training, flexible tactile interaction and other scenarios. The entire fabrication process eliminates high-precision micro-nano processing equipment such as photolithography systems, plasma etchers and 3D printers; only general chemical raw materials and conventional laboratory instruments are adopted. The reusable templates enable low manufacturing costs and large-area coating forming, offering a novel low-cost technical solution for the engineering implementation and industrialization of high-performance iontronic flexible pressure sensors. Full article

To address the challenges encountered in the simulation and parameter extraction of distributed-feedback (DFB) lasers, this work starts from the rate equations of the DFB laser to derive its steady-state formulation and small-signal model, and constructs steady-state and transient KAN-based physics-informed neural-network (KAN-PINN) architectures. In the steady state, accurate L-I/I–V curves and $-3\mathrm{dB}$ bandwidth results are obtained. In addition, the parameters of the DFB laser are systematically organized, and a KAN-PINN inverse mode, an adaptive moment estimation (Adam) optimizer-based physical inversion, and a hybrid strategy combining the two are proposed. The extracted parameters show small deviations from the true values, and the simulation results agree well with the actual data. The proposed methodology can be extended to other lasers and even to a broader class of optoelectronic devices for parameter extraction and simulation. Full article

Shear-wave time-of-flight (TOF) measurement enables controlled assessment of frequency-dependent wave propagation, but its feasibility in biological tissues remains insufficiently established. This study evaluated whether a custom shear-wave TOF device could detect frequency- and direction-dependent responses in ex vivo tissues. Three porcine liver samples and three chicken breast samples were examined. Chicken breast was measured with propagation parallel and perpendicular to visible muscle fibers. One-cycle sinusoidal excitations were applied at 40–160 Hz, with 50 acquisitions ensemble-averaged per sample–frequency measurement. TOF was estimated using Tx threshold detection and cumulative-energy-based Rx onset detection, and TOF-derived apparent shear-wave propagation speed was calculated from the Tx–Rx distance and the measured TOF. Frequency-dependent data were fitted using the Kelvin–Voigt fractional derivative model to obtain model-dependent KVFD fit parameters. Signal quality was assessed, and a preliminary descriptive comparison with HISKY EQTouch UD3000 (Wuxi Hisky Medical Technologies Co., Ltd., Wuxi, China) SWE was performed. All 63 averaged sample–frequency measurements satisfied the predefined primary-detection criteria. Mean apparent shear-wave speed was 3.145 m/s in porcine liver, 6.133 m/s in chicken breast measured parallel to the fibers, and 5.914 m/s in chicken breast measured perpendicular to the fibers, giving a parallel-to-perpendicular speed ratio of 1.037. Mean post-averaging, post-processing SNR ranged from 24.47 to 31.52 dB. The UD3000 comparison showed the same tissue ranking. The device detected frequency- and direction-dependent responses in averaged ex vivo signals, supporting its feasibility as a controlled research platform. Claims of absolute stiffness accuracy and intrinsic muscle anisotropy require independent calibration and validation. Full article

There is an increasing demand for ultrasound imaging technologies, particularly wearable and portable systems, for continuous physiological monitoring applications. Although some recent flexible ultrasound devices have adopted polymer encapsulations, typical rigid transducer designs still include metal housings and costly electrodes, contributing to increased device weight and fabrication cost. To address these limitations, we developed an aluminum-electrode/3D-printed polymer-housing ultrasound transducer (APUT) utilizing a polyvinylidene fluoride piezoelectric film. Compared to a gold-electrode/metal-housing ultrasound transducer, the APUT material costs and total weight were approximately 66% and 86% lower, respectively. Acoustic evaluation revealed a center frequency of 24.5 MHz and a fractional bandwidth of 60.9%, with axial and lateral resolutions of 51 and 152 μm, respectively. Furthermore, during a 3-h pulsed operation test, the APUT exhibited an initial increase in capacitance followed by a relatively stable response, with no progressive surface-temperature increase detected within the accuracy of the measurement method. Finally, successful ex vivo imaging of chicken breast tissue confirms the APUT’s biomedical applicability, highlighting its potential as a wearable, portable, and disposable ultrasound platform. Full article