Search Results (4,028)

Dealloyed nanoporous metals have a unique bicontinuous solid/void structure that provides a sizable surface area and outstanding electrical conductivity, making them attractive candidates for use in a range of applications. But for many of these applications, the utilization of an engineered hierarchical porous network topology that promotes and optimizes mass transport would be quite advantageous. We present a soft template approach for the routine fabrication of hierarchical multimodal nanoporous gold monolith (hm-NPG). This self-supporting framework composed of multimodal porosity is produced employing a synergistic mix of metal reduction, templating, annealing, and chemical dealloying. This method provides for the simultaneous optimization of active surface area and mass transport in a porous metal electrode. It is reliable, simple, economical, accessible, and environmentally friendly. The procedure should be scalable and can produce hm-NPG for use in applications such as biosensing, energy systems, biofiltration, and catalysis. The material visually displays two visibly unique structural length scales that range from the macroporous network structure (average pore size of 0.58 ± 0.29 μm) to the mesoporous pore/ligament morphology (average pore size of 37 ± 10 nm) as determined by SEM analysis. Modification by self-assembly with lipoic acid (LA) gave a coverage of 5.12 × 10¹⁴ molecules/cm² of the hm-NPG surface, according to calculations made using thermogravimetric analysis (TGA) data. Following the dealloying procedure, a compositional study of the np-Au monolith using EDS revealed that it was almost 98.2 atomic % gold. The specific surface area of the hm-NPG was found to be 7.84 ± 0.01 m²/g (n = 3) through analysis utilizing the Brunauer–Emmett–Teller (BET) multi-point surface area method applied to krypton adsorption isotherms. BET analysis using N₂ adsorption isotherms and the Barrett–Joyner–Halenda (BJH) pore distribution analysis gives strong evidence for the additional presence of micropores of diameter 2–3 nm, thus making the material likely trimodal. Full article

In order to meet its need of functional improvement, the existing masonry structure generally adopts the method of replacing partial walls with concrete frame columns to expand the openings and reduce the number of the longitudinal walls. However, the partial removal of longitudinal masonry walls and the introduction of large openings may result in a nonuniform distribution of lateral stiffness in plan and consequently induce torsional response under horizontal seismic loading. In order to investigate the seismic performance of the existing masonry structure after replacement, a 1:4 scale four-story brick masonry–concrete structure model was designed and made. Based on the principle of stiffness equivalence, the partial walls on the side of the large openings of the model ground-level floor were replaced by frame columns and frame beams, and then the pseudo-static test was conducted on the model. Through the test, the failure patterns of each floor in the structure and the seismic performance indexes such as hysteresis curve, skeleton curve, displacement ductility, stiffness degradation, and energy dissipation capacity, were obtained. The results showed that the yield load of the ground-level floor with the equivalent frame columns is approximately 138% of that of the second and third floors, while its yield displacement is approximately 59% of that of them. That is, after the structure enters the yield stage, its ground-level floor has good bearing capacity and resistance to deformation. The ground-level floor of the structure consumes the least energy as compared to the second and third floors, while the second floor consumes the most energy and has stiffness mutation, and the damage to the walls in such layer is also the most serious. Hence, seismic strengthening of the second story should be considered to prevent the formation of a weak or soft story and the consequent risk of structural collapse. Although there is a significant difference in the material properties between reinforced concrete frames and masonry structures, it is feasible to use the replacement method based on the stiffness equivalence to solve the problem of structure torsion caused by the irregular plane arrangement. Full article

The thermal contact resistance between a clip-attached TO 247 package and heat sink is a very large contributor to the total thermal resistance. Therefore, it is important to investigate its reliability and lifetime behavior. The novelty of this investigation is the new, detailed lifetime behavior measurement results of thermal contact resistance between package and heat sink. We have carried out an accelerated lifetime test on 30 samples at 110 °C with acceleration factor of 35 for 18 weeks, corresponding to 12.1 years operating life in indoor environments. The samples were 7 without interlayer film, 12 with 12.5 µm thick silver film and 11 with 6 µm thick silver film. At the start of the test, the average of the thermal contact resistance of samples with 12.5 µm silver film was 20.7% lower, and with 6 µm silver film, the average of thermal contact resistance was 8.7% lower than the average of thermal contact resistance of samples without film. During the first operating month, thermal contact resistance decreased by an average of 5%. Then followed an additional 5% decrease for 12 years. All individual samples show lower thermal contact resistance after 12.1 years compared to the start. No failures were observed, not even among high outliers. By a visual inspection of heat sink surfaces, high outliers can be avoided from start. The thermal contact resistance variation is smaller for samples with silver films compared to samples without film. Samples show decreasing thermal contact resistance with increasing dissipated power. Several previously known stabilizing mechanisms can hypothetically explain the results. Not only the softness of silver, but also the high ductility and Poisson Ratio, which elongate a 12.5 µm thick film more than a 6 µm thick µm film, are hypothesized to better fill out microscopic voids. We observe silver film surface structure changes when comparing aged silver films to un-aged silver films, indicating material movements, but no exact mechanism could be proven. Therefore, the explanations studied are hypothetical. Since all measured thermal contact resistances were lower after 12.1 years, our conclusion is that stabilizing types of mechanisms are dominant during the operating lifetime for indoor environments. Full article

Driven by the goals of carbon peaking and carbon neutrality, as well as the increasing demand for green construction materials, traditional petroleum-based asphalt can no longer fully meet the requirements of long-life and low-carbon road construction due to its strong resource dependence, susceptibility to aging, and difficulty in balancing high- and low-temperature performance. Bio-based polyurethane-modified asphalt (Bio-PUMA) uses renewable or waste biomass to construct high-performance polyurethane (PU) networks, providing a new way to improve pavement performance, reduce carbon emissions, and support the sustainable development of road materials. This paper reviews the molecular structural characteristics of bio-based precursors, including vegetable oil, rosin, and lignin, and summarizes their effects on PU network formation, asphalt microphase morphology, and pavement performance. Existing studies show that the functionality, molecular backbone, hydroxyl value, and soft-to-hard segment ratio of bio-based polyols govern the crosslinking density, phase continuity, and asphalt compatibility of polyurethane networks, thereby influencing rutting resistance, cracking resistance, aging resistance, interfacial adhesion, and mixture performance. Current challenges include unstable biomass feedstocks, difficulty in balancing low-temperature toughness and high-temperature strength, limited long-term service data, and incomplete life-cycle assessment. Future studies should focus on precursor standardization, precise molecular design, multiscale performance evaluation, and engineering validation to promote the application of Bio-PUMA in long-life, low-carbon, and large-scale road infrastructure. Full article

During long-term service, asphalt pavements undergo environmental stress and ageing, which cause cracking, rutting, and other distresses and raise maintenance costs. Polyurethane (PU) has high mechanical strength, elastic recovery, and ageing resistance due to its unique molecular structure. As an asphalt modifier, PU has been reported to improve high-temperature stability, moisture resistance, and durability. However, PU and asphalt differ greatly in polarity, density, viscosity, and phase structure, and these differences often lead to segregation and phase separation. The prepolymer method can mitigate these compatibility limitations by adjusting molecular weight, terminal-group activity, and soft/hard segment ratio before dispersion, chain extension, crosslinking, and post-curing in asphalt, resulting in better compatibility and more controllable processing. This review discusses PU soft/hard segment structures, asphalt composition, prepolymer synthesis and curing, microstructural evolution, pavement performance, storage stability, and use in other systems to clarify modification mechanisms and potential applications. This critical review aims to clarify material–reaction–process–performance relationships within the prepolymer route, with scope limited to molecular design, preparation mechanisms, performance, storage stability, and representative engineering applications. Future work should consider real service conditions and build multiscale evaluation frameworks that jointly optimise prepolymer design, processing, storage stability, and pavement performance, helping translate laboratory findings into low-carbon, long-life road materials that can be produced at scale. Full article

Soft iontronic devices, which utilize ions as charge carriers and integrate flexibility and stretchability, exhibit diverse carrier species, high biocompatibility, multimodal stimulus responsiveness, and strong resistance to electromagnetic interference. These features make them highly promising for applications in ionic circuits, flexible sensing, implantable systems, and neuromorphic information processing. Among them, soft iontronic diodes have attracted sustained attention over the past two decades as fundamental building blocks of functional circuits. This review systematically summarizes the material types of soft iontronic diodes and their influence on key device performance. It further elucidates the mechanisms underlying ionic rectification and highlights recent advances in logic gate implementation, energy harvesting, flexible sensing, and neuromorphic computing. Finally, we discuss key challenges and future opportunities in this field, aiming to provide design principles and mechanistic insights for the development and application of soft iontronic diodes. Full article

Hyaluronic acid (HA) is a glycosaminoglycan that is found within the body and has both structural and signaling functions in the extracellular matrix. HA is biocompatible and biodegradable; it has a high water content and binds directly to certain cell-surface proteins. Due to these characteristics, it is considered a promising component for the design of biomaterials for regenerative wound healing. This review covers the most recent findings on the use of HA-based biomaterials in soft tissue repair, while also incorporating earlier, foundational studies relevant to the field, focusing on HA’s characteristics, cellular interactions, design, and preclinical and clinical results. The physicochemical characteristics of HA and their influence on cellular responses and tissue regeneration are discussed to show how material properties can be adjusted for specific therapeutic purposes. There have been great advances in chemically modified composite scaffolds and HA matrices, which offer better mechanical stability and controlled degradation. At the same time, new delivery systems have been built using HA, from nanoparticles to gene delivery platforms and growth factors, and these have given the material an active role as a therapeutic agent rather than just a passive one. This narrative review covers the clinical evidence for the effectiveness of commercial products for acute and diabetic wounds, as well as burns and chronic wounds, and discusses where their use is indicated. In the end, the current limitations of the research and future applications and directions are discussed. Full article

Fused filament fabrication (FFF) is one of the most widely adopted additive manufacturing methods for thermoplastic polyurethane (TPU)-based soft pneumatic actuators, enabling low-cost fabrication, geometric customization, embedded pneumatic architectures, and rapid prototyping for soft robotic systems. However, despite these advantages, achieving reliable airtightness remains a major challenge due to process-induced anisotropy, interlayer voids, incomplete filament fusion, residual porosity, seam discontinuities, material permeability, and interface-related leakage. These defects can significantly reduce pressure retention, actuation efficiency, deformation repeatability, and long-term pneumatic reliability. This review systematically examines the dominant leakage mechanisms affecting FFF-printed soft pneumatic actuators and comparatively analyzes fabrication approaches, TPU material systems, geometric design factors, post-processing methods, sealing strategies, and leakage characterization techniques. Representative experimental observations, including pressure-decay testing, submerged-bubble visualization, microscopy, and localized thermal surface treatment, are also discussed to connect the findings reported in the literature with experimentally observed leakage behavior. Emerging analytical leakage models, sensing technologies, AI-assisted predictive monitoring, and digital-twin-enabled manufacturing frameworks are reviewed as promising approaches for developing leakage-aware soft robotic systems. The review highlights current limitations related to standardized leakage testing, cyclic durability evaluation, scalable sealing strategies, and intelligent manufacturing integration. Overall, airtightness is identified as a coupled material-process-geometry challenge that must be systematically addressed to improve the reliability, scalability, and long-term operational stability of next-generation TPU-based soft pneumatic actuators. The review was conducted following the PRISMA-ScR framework and includes 248 studies published between 2017 and 2026. Full article

Soft actuators made from soft organic materials that can exhibit biomimetic motions, such as artificial muscles, have recently attracted substantial interest for applications in soft robotics, wearable electronics, and haptic interfaces, where flexible, adaptive, and biocompatible actuation is essential. In this context, piezoelectric and electroactive materials have emerged as important platforms for electromechanical transduction; however, conventional piezoelectric materials are predominantly ceramic-based, making them brittle, limiting achievable strain, and often requiring high operating voltages. Ionic liquids (ILs) have emerged as promising alternatives due to their high ionic conductivity, negligible volatility, and wide thermal and electrochemical stability windows. Notably, recent reports of piezoelectric behavior in ionic liquids, representing the first observation of such effects in liquid systems, have opened new opportunities for IL-based soft actuators. These advances highlight the potential of IL-based materials for developing next-generation soft robotic systems with enhanced functionality. Accordingly, there is a growing interest in designing sustainable actuators that integrate self-healing, self-powering, and self-actuating capabilities while maintaining efficient energy use, long-term stability, and user-specific adaptability. This review summarizes recent progress in IL-based soft actuators, including material design, actuation mechanisms, sensing integration, and control strategies, and also discusses current challenges and future research directions in this emerging field. Full article

Programmable hydrogel actuators represent an innovative group of adaptive soft matter systems, which are able to respond to external stimuli with controllable mechanical movements for biomedical and bioengineering purposes. Natural silk fibroin (SF) is known to be a peculiar biomaterial, since it can exhibit controllable β-sheet-induced structural transitions, hierarchical self-assemblies, high biocompatibility, and mechanical adaptability, thus representing an ideal candidate for the development of dynamic hydrogels. In contrast to earlier reviews which focused more on SF hydrogel synthesis or biomedical applications, this review presents a mechanism-based understanding of programmable bioactuation by carefully correlating molecular design, network formation, stimuli responsiveness, and macroscopic deformation. Recent developments in SF hydrogel actuators are critically compared in terms of actuation principles, deformation behaviors, response dynamics, mechanical robustness, and functionalization, noting the natural compromise between fast response, strength generation, and durability in such materials. Novel concepts like nanocomposite materials, bioinspired designs, shape memory systems, and 4D printing are described as efficient ways to improve programmable deformation and functionality in soft materials. In addition, the biomedical opportunities of responsive SF hydrogels in wound healing, drug delivery, tissue engineering, wearable biosensors, and soft robots are critically discussed in relation to existing barriers for translation into practice. Combining mechanistic understanding with the comparative assessment of the performance of hydrogels is a basis for developing a complete rationale for the design of the next generation of SF hydrogel actuators and smart shape deformations. Full article

To elucidate the formation of crosslinked products and their influence on material degradation, thermoplastic polyurethane (TPU) films were subjected to accelerated UV aging for various durations. Post-aging, the samples underwent Soxhlet extraction with tetrahydrofuran (THF), yielding an insoluble fraction—operationally defined as the crosslinked product—and a soluble uncrosslinked fraction. The mechanical properties, molecular weight distribution, swelling behavior, thermal properties, and chemical structure were analyzed. As UV aging progressed, both tensile strength and elongation at break deteriorated markedly. Concurrently, GPC analysis revealed a continuous decrease in molecular weight and a broadening of the molecular weight distribution, confirming that chain scission was the dominant degradation pathway. An insoluble network-like residue, defined as the crosslinked product, first appeared after 12 h of aging, with its content increasing to 22.9% after 300 h. Swelling tests showed that the crosslinked product had a high gel fraction, and its swelling ratio decreased from 196.8% to 157.4%, indicating the formation of a stable and increasingly dense network. DSC and TG results revealed restricted segmental motion, altered thermal transition behavior, and enhanced char-forming ability. The glass transition temperature of the crosslinked product exceeded that of the pristine TPU film. FTIR analysis showed variations in the -NH₂, C=O, C-O, and C-O-C bands, confirming structural evolution within both hard and soft segments. In summary, UV aging of TPU involves a complex interplay among chain scission, degradation of soft segments, rearrangement of hard segments, evolution of hydrogen bonds, and radical-induced crosslinking. Crucially, the crosslinked network formed during aging plays a pivotal role in determining the macroscopic structural, thermal, and mechanical properties of the polymer. Full article

Japonica soft rice varieties possess excellent eating quality, and their cultivation area has been steadily expanding in recent years. This study aimed to analyze japonica soft rice varieties cultivated in the Yangtze River Delta region of China at the genome level and to provide a theoretical basis for optimizing disease resistance and other important traits. Genotypic characterization and evaluation of ten major japonica soft rice varieties from the Yangtze River Delta region were conducted using a genome-wide single nucleotide polymorphism (SNP) chip. The experimental results indicated that the soft rice varieties in the Yangtze River Delta region had a relatively high japonica component and were all classified as typical japonica rice varieties. Specifically, the highest (95.6%) and lowest (91.5%) proportions of japonica genomic segments were detected in Tai’an 1 and Zhehexiang 2, respectively. Japonica soft rice varieties from Shanghai exhibited a closer genetic distance to those from Jiangsu Province than to those from Zhejiang Province. Genomic identity was highest between Tai’an 1 and Nanjing 46 (87.9%) and lowest between Tai’an 1 and Jia 67 (74.4%). Based on the results of the chip assay, a total of twenty-six functional genes controlling key traits, such as yield, quality, and resistance to biotic and abiotic stresses, were identified in the ten analyzed varieties. Among them, Zhehexiang 2 carried the broad-spectrum blast resistance genes Pi2 and Pita, which is useful for improving the blast resistance of japonica soft rice varieties. The findings of this study provide genetic resources and carrier materials for the efficient molecular improvement of japonica soft rice varieties. Full article

Background and Objectives: The wrist is one of the most common sites of rheumatic disease. Based on the graded deformities of Larsen et al., surgery has been adapted to minimize harm while maximizing benefit to the individual. This study aims to survey the institutional experience, describing functional outcomes and patient satisfaction across several surgical approaches, without formal statistical comparison. Materials and Methods: The studies and results presented here are from one center specialized in rheumaorthopedic surgery and reflect the above concepts. The studies cover a broad spectrum of surgical techniques, which were categorized according to the Larsen stages of wrist destruction. All studies were retrospective or retrospective-like, and follow-up data were analyzed collectively. The primary endpoints were functional outcome scales and patient satisfaction, supplemented by pain relief, as well as strength and range of motion. The assessment utilized, amongst others, the QuickDASH, FFbH and Clayton score, as well as appropriate patient-reported measures such as ADL and SF-36. Radiological follow-ups were classified according to the Larsen–Dale–Eek classification; for endoprostheses/arthrodesis, carpal height was determined according to Youme. Results: Significant improvements in the Clayton score (consistently greater postoperatively than preoperatively) are evident for several procedures, particularly MPW^® (+37 points) and APW^® (+28 points). Postoperative reductions in VAS pain scores are marked for most procedures, e.g., MPW^® from 7 to 1.8. The revision rates for most procedures are around 10–13% during the follow-up periods. In addition, the tendon and soft tissue functions of the hand(s) play critical roles in these PROMs. Conclusions: The studies present the results and limitations of surgical treatment for rheumatic wrists in the prebiological era. The results of individual studies need to be examined more closely to better assess the potential and limitations of surgery for patients. Full article

Silicone gel (SG) is widely used as a soft encapsulation material for high-voltage power devices because of its excellent flexibility, thermal stability, and electrical insulation. However, its intrinsically low thermal conductivity and susceptibility to partial discharge (PD) at triple-junction interfaces restrict long-term operational reliability. In this study, polydopamine-modified hexagonal boron nitride (P-BN) was introduced into silicone gel to construct thermally conductive and electrically insulating composites. The SG/P-BN composites exhibited reduced filler agglomeration and a more continuous filler–matrix morphology than the corresponding SG/BN composites, while the model-extrapolated trap analysis suggested composition-dependent changes in the higher energy charge trapping states of the P-BN-containing composites. As a result, the SG/P-BN composites exhibited enhanced thermal stability, reduced coefficient of thermal expansion, and improved heat-transfer capability, with thermal conductivity increasing from 0.183 W/m·K for pristine SG to 0.25 W/m·K. The composite containing 2 wt% P-BN showed the best insulation performance, with breakdown strength increasing from 24.05 to 28.45 kV/mm at 25 °C and from 19.59 to 24.71 kV/mm at 150 °C. Under a simplified triple-junction laboratory configuration, the PD inception voltage increased from approximately 3.1 kV for pristine SG to 4.1 kV for SG/P-BN₂, accompanied by fewer high-amplitude discharges. This work demonstrates improved material-level thermal conductivity and electrical insulation performance of P-BN-containing silicone gel composites under the investigated laboratory conditions. Full article

Driven by the rising frequency of extreme climatic events and the escalating demand for sustainable infrastructure, modern pavement materials must deliver enhanced resilience, structural stability, and environmental adaptability. This study presents the design and synthesis of a novel polyurethane-polyurea (PU-PUa) pavement binder, engineered via a synergistic framework combining nanoscale microphase separation and a hierarchical hydrogen-bonding network. Utilizing a streamlined, one-step synthesis approach involving an aliphatic isocyanate, a polyaspartic ester, polytetramethylene ether glycol, and 1,4-butanediol, the PU-PUa copolymer achieves distinct nanoscale phase separation between its hard and soft segments. Fourier transform infrared (FTIR) spectroscopy verifies the successful formation of characteristic PU-PUa moieties and a multi-scale hydrogen-bonding network, while DSC and DMA reveal SSC-dependent soft-segment mobility, crystallization/melting behavior, and viscoelastic relaxation. These intra- and inter-segmental interactions, together with thermally activated soft-segment transitions, establish the structural foundation for the macro-performance enhancement of the system. Comprehensive evaluations demonstrate that the PU-PUa binder exhibits excellent mechanical and highly tunable properties. Rheological measurements indicate that increasing the soft segment content (SSC) or incorporating an appropriate diluent concentration significantly lowers the system viscosity, thereby enhancing processing workability during mixing and paving. Contact angle goniometry reveals that the surface hydrophobicity of PU-PUa can be effectively regulated by adjusting the SSC, offering a viable strategy to optimize moisture damage resistance. Moreover, curing behavior analyses show that the polymerization kinetics are strictly governed by both the SSC and environmental temperature, where a lower SSC or elevated curing temperature accelerates strength development. Mechanically, the PU-PUa binder displays desirable surface hardness (>80 Shore A) and exceptional aggregate adhesion (>2 MPa), ensuring robust bonding stability and resistance to traffic-induced abrasion. Characterized by balanced tensile performance, the elongation at break of the binder can be tailored from 90% to 161%, while its tensile strength varies between 6.4 MPa and 17.8 MPa at intermediate temperatures, manifesting excellent resilience and cracking resistance. Overall, this molecular-to-macroscopic design strategy establishes the PU-PUa copolymer as a highly promising, durable binder for next-generation resilient pavement infrastructures. Full article