Linear stability analysis of rarefied gas flows based on kinetic equations is computationally demanding due to the high dimensionality of the distribution function. Spectral methods offer exponential convergence but incur prohibitive memory and time costs from dense matrices, while uniform finite difference schemes may suffer from convergence difficulties near solid boundaries with steep gradients. This study develops a non-uniform fourth-order finite difference scheme (non4FD) based on Chebyshev collocation points for stability analysis using the Shakhov kinetic model. The scheme is validated through Rayleigh-Bénard convection (Knudsen numbers 0.0005-0.04, temperature ratios 0.5-0.9) and compressible Couette flow (Knudsen numbers 0.005-0.02, Mach numbers 1.0-2.0). Compared with the Chebyshev spectral method, the non4FD scheme reduces CPU time by up to a factor of 30 and memory usage by one to two orders of magnitude, while keeping relative errors of the most unstable mode below 0.2%. Unlike the uniform fourth-order scheme, which exhibits error growth upon grid refinement in Couette flow, the non4FD scheme converges monotonically under all tested conditions. By concentrating grid points near walls where gradients are largest, the method provides an efficient and robust tool for kinetic stability analysis of rarefied gas flows in the slip and transitional regimes.

Achieving high toughness and strength simultaneously in single-covalent-network hydrogels remains a longstanding challenge. Herein, we report a simple yet effective strategy to resolve this strength-toughness conflict by constructing polyacrylamide (PAAm) networks with abundant dangling chains that form transient entanglements. Unlike permanently trapped entanglements, these transient entanglements can slip and fully disentangle upon loading, enabling highly efficient energy dissipation and stress redistribution over a broad range of strains. Besides, these networks exhibit superior homogeneity compared to other structures, effectively mitigating stress concentration. As a result, our single-covalent-network hydrogels exhibit good mechanical properties, including a fracture strain of 5071%, a fracture strength of 1.06 MPa, a fatigue threshold of 1968 J·m⁻², and a fracture energy of approximately 60,000 J·m⁻². Moreover, these hydrogels feature low friction and high wear-resistance. Such a simple yet robust design paradigm effectively overcomes the longstanding strength-toughness trade-off without the complexity of multi-network architectures, opening avenues for next-generation hydrogels in biomedicine, wearable electronics, and other demanding environments.

Simulating microstructure evolution (MicroEvo) is vital for materials design but demands high numerical accuracy, efficiency, and physical fidelity. Although recent studies on deep learning (DL) offers a promising alternative to traditional solvers, the field lacks standardized benchmarks. Existing studies are flawed due to a lack of comparing specialized MicroEvo DL models with state-of-the-art spatio-temporal architectures, an overemphasis on numerical accuracy over physical fidelity, and a failure to analyze error propagation over time. To address these gaps, we introduce MicroEvoEval, the first comprehensive benchmark for image-based microstructure evolution prediction. We evaluate 14 models, encompassing both domain-specific and general-purpose architectures, across four representative MicroEvo tasks with datasets specifically structured for both short- and long-term assessment. Our multi-faceted evaluation framework goes beyond numerical accuracy and computational cost, incorporating a curated set of structure-preserving metrics to assess physical fidelity. Our extensive evaluations yield several key insights. Notably, we find that modern architectures (e.g., VMamba), not only achieve superior long-term stability and physical fidelity but also operate with an order-of-magnitude greater computational efficiency. The results highlight the necessity of holistic evaluation and identify these modern architectures as a highly promising direction for developing efficient and reliable surrogate models in data-driven materials science.

Diabetic implant osseointegration presents a significant clinical challenge due to complex pathophysiology and limited therapeutic options. Mitochondrial dysfunction and endoplasmic reticulum (ER) stress act synergistically through a vicious cycle, collectively leading to osteoblast failure and reduced bone formation, which are key contributors to abnormal bone metabolism in the diabetic state. This study developed an injectable photocrosslinkable silk fibroin hydrogel incorporating Mdivi-1 (Mdi@SilMA), which integrates shear-thinning injectability, sustained drug release, mitochondrial function regulation, and bone formation promotion. In vivo investigations demonstrated that Mdi@SilMA significantly enhanced diabetic osseointegration compared to plain silk hydrogels by suppressing pathological mitochondrial fission, restoring HO-1-mediated antioxidant defenses, and preserving osteogenic capacity through RANKL/OPG axis modulation. The therapeutic efficacy of Mdivi-1 stems from its targeted binding to the GTPase domain of Drp1, which results in the restoration of mitochondrial homeostasis by mitochondrial dynamic recovery, ROS elimination, and subsequent ER stress mitigation. This coordinated action facilitates mitochondrial quality control, reestablishes cellular functional homeostasis, and ultimately promotes osteogenesis. These findings establish Mdivi-1 as a promising therapeutic agent while providing a novel theoretical framework for targeting ER-mitochondrial crosstalk in diabetic bone metabolism.

Hydrogel coatings endow traditional materials with excellent lubrication performance, meeting the needs of biomedical and lubrication applications. In this work, we propose a lubrication enhancement strategy for hydrogel coatings based on a mechanochemically triggered dangling-chain grafting strategy. Mechanical shear/friction of the covalent network triggers chain scission and simultaneously generates mechanoradicals that initiate the preloading monomer polymerization, grafting a dense, hydrated dangling chain onto the fracture network. The generation of mechanoradicals was verified through DPPH assays, and the stable grafting of dangling chains was proved by wettability, spectrum, modulus, and friction characterizations. The lubricating structure constructed by this method significantly reduces friction and enhances wear resistance, maintaining a stable friction coefficient (CoF approximate to 0.007) over 18,000 cycles. Moreover, when the monomer solution is preloaded within the hydrogel network, friction and wear can trigger in situ regeneration of lubricating dangling-chain layers by a mechanochemical process, achieving long-term self-adaptive lubrication. This strategy also enables surface functionalization by preloading different monomer solutions. It offers a simple, universal route for constructing durable, functional, and adaptive hydrogel coatings.

Supramolecular polymers often exhibit self-healing capabilities following mechanical damage. However, the detailed recovery processes and underlying driving forces remain poorly understood. In this study, we developed a room-temperature self-healing elastomer by introducing intermolecular ionic interactions between untangled polymer chains. These interactions enable the material to fully repair macroscopic mechanical damage (e.g., cuts) within 5 h at room temperature without compromising its mechanical properties. We quantitatively characterize the multiscale healing processes, ranging from ionic bond reformation and weak physical network repair to strong physical network recovery and mechanical property restoration. These healing processes are systematically correlated with the multiscale molecular motions and relaxation dynamics of ionic aggregates. Our findings reveal that ionic bond recovery occurs synergistically with segmental motion, facilitating the repair of a weak physical network and driving shape recovery after deformation. Meanwhile, the restoration of the strong network is governed by the complete relaxation of the ionic aggregates. For macroscopic damage, full healing requires an additional contribution of terminal flow.

Postoperative abdominal adhesion, coupled with adverse effects, threatens to patient’s life. However, most bioadhesives as anti-tissue adhesion barrier encounter unreliable adhesion towards slippery abdominal wall along with accidental mispositioning during use, even overlook the impact of frictional stimuli and inflammation on abdominal adhesion. Herein, inspired by lubricated peritoneum, a programmable adhesive dual-layer Janus patch (DJP) barrier with unilateral lubrication and anti-inflammation integrating lubricated layer and adhesive matrix is developed to prevent postoperative abdominal adhesion. Programmable adhesion of DJP rapidly establishes adhesion interface between barrier and tissue primarily through noncovalent interaction, then enhances the interfacial stability of 2.81-fold through covalent interaction. This timescale-dependent adhesion can also allow the mispositioned bioadhesive to be repositioned on tissue in short time, improving surgical fault tolerance. Hydration of micron-scale poly sulfobetaine methacrylamide brush on DJP surface imitates peritoneal lubrication with low coefficient of friction (0.06), diminishing frictional stimuli towards injured tissue. Meanwhile, anti-inflammation of DJP by the antioxidative catechol-containing copolymer is demonstrated in vitro. Further, a rat model indicates that DJP adhering to injured site reduces deposited collagen between abdominal wall and cecum, preventing abdominal adhesion and facilitating tissue healing compared with commercial barriers. Overall, this work provides a notable guiding reference in development of antiadhesive biomaterials.

Concurrent multiscale methods play an important role in modeling and simulating materials with defects, aiming to achieve the balance between accuracy and efficiency. Atomistic-to-continuum (a/c) coupling methods, a typical class of concurrent multiscale methods, link atomic-scale simulations with continuum mechanics. Existing a/c methods adopt the classic second-order Cauchy-Born approximation as the continuum mechanics model. In this work, we employ a higher-order Cauchy-Born model to study the potential accuracy improvement of the coupling scheme. In particular, we develop an energy-based blended atomistic to higher-order continuum method and present a rigorous a priori error analysis. We show that the overall accuracy of the energy-based blended method is not actually improved due the coupling interface error which is of lower order and may not be improved. On the contrast, higher order accuracy is achieved by the force-based blended atomistic to higher-order continuum method. Our theoretical results are demonstrated by a detailed numerical study.

Epoxy resins are the most widely used thermosets, yet they typically lack the capability to self-heal at room temperature due to their molecular chains and networks being immobilized in a glassy state. Herein, machine learning identifies fractional free volume as a crucial factor for enabling self-healing in the glassy state. Guided by this insight, we designed an epoxy network incorporating dangling chains together with numerous hydrogen bonds and aromatic disulfide bonds. The dangling chains introduce large free volume, facilitating the reorganization of hydrogen bonds and the radical-mediated exchange of aromatic disulfide bonds, thereby imparting prominent self-healing capability at room temperature. Notably, the damaged epoxy not only can recover 81.2% of its tensile strength without intervention but also can autonomously and completely eliminate electrical tree damage and scratches at room temperature. Under mild compression, 100% healing occurs within tens of minutes in the glassy state. Additionally, the optimized epoxy exhibits high physicomechanical properties with a tensile strength of 42.1 MPa, a modulus of 2.9 GPa, and a glass transition temperature of 53.2 degrees C. Its ability to self-heal both electrical tree and mechanical damage at room temperature positions this epoxy as a promising material for advanced insulating and sealing applications.

Achieving sufficient bone regeneration in osteoporotic defects remains a significant challenge due to compromised osteogenic capacity and inadequate vascularization. In this study, we developed a novel hollow-tube whisker-modified biphasic calcium phosphate ceramic system integrated with deferoxamine (DFO/BCP-HW) through hydrothermal treatment. The hierarchically structured DFO/BCP-HW exhibited enhanced mechanical properties and superior drug loading capacity with sustained release behavior compared to conventional BCP ceramics. In vitro studies demonstrated excellent biocompatibility and proliferation-promoting effects of DFO/ BCP-HW. The composite system effectively enhanced endothelial cell migration and tube formation while simultaneously promoting the osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs). Gene transcriptome analysis revealed that this enhanced bone formation was associated with activation of the hypoxiainducible factor-1 alpha (HIF-1 alpha) pathway in response to DFO release from the ceramic system. In the osteoporotic rat femoral defect model, the DFO/BCP-HW group showed significantly improved bone regeneration and enhanced vascularization at 8 weeks post-implantation, as evidenced by micro-CT analysis, histological examination, and immunofluorescence staining of osteogenic and angiogenic markers. These findings demonstrate that the DFO/ BCP-HW system presents a promising strategy for treating osteoporotic bone defects.

In the field of high-speed flight, the transition of the upper boundary layer of the aircraft has an significant impact on the aerodynamic characteristics and thermal protection of the aircraft. The classical Navier-Stokes (N-S) equations commonly have limitations because of the rarefied gas effect in the gas flow. The Boltzmann equation is based on the kinetic theory, which is suitable for the stability analysis of the whole region flow, and has gradually achieved in-depth application in the field of rarefied flow. Considering the temperature disturbance, the Boltzmann model equation is difficult to properly predict the Prandtl-number (Pr), which cannot reflect the real thermal environment of gas flow. It is necessary to use the BGK-Shakhov model equation with modified Prandtl number to study the linear stability of flow under temperature disturbance. However, the effectiveness of the stability analysis method based on BGK-Shakhov has consistently been the main problem in the promotion of this method. In order to verify the accuracy and effectiveness of the linear stability equation based on BGK-Shakhov equation (SBGK-LSE), the theoretical relationship between SBGK-LSE and NS-LSEs is utilized by the Chapman-Enskog expansion method and the method of moments under the continuum assumption, and the rigorous mathematical derivation of recovering NS-LSEs from SBGK-LSE is given. Finally, the numerical results are verified by typical examples. This provides theoretical support for the flow linear stability analysis method based on the BGK-Shakhov model equation.

The atomistic-to-continuum (a/c) coupling methods, also known as the quasicontinuum (QC) methods, are a important class of concurrent multisacle methods for modeling and simulating materials with defects. The a/c methods aim to balance the accuracy and efficiency by coupling a molecular mechanics model (also termed as the atomistic model) in the vicinity of localized defects with the Cauchy-Born approximation of the atomistic model in the elastic far field. However, since both the molecular mechanics model and its Cauchy-Born approximation are usually a nonlinear, it potentially leads to a high computational cost for large-scale simulations. In this work, we propose an advancement of the classic quasinonlocal (QNL) a/c coupling method by incorporating a linearized Cauchy-Born model to reduce the computational cost. We present a rigorous a priori error analysis for this QNL method with linear elasticity enhancement (QNLL method), and show both analytically and numerically that it achieves the same convergence behavior as the classic (nonlinear) QNL method by proper determination of certain parameters relating to domain decomposition and finite element discretization. More importantly, our numerical experiments demonstrate that the QNLL method perform an substantial improvement of the computational efficiency in term of CPU times.

Diabetic chronic wounds pose a significant clinical challenge due to their complex pathophysiology and limited treatment options. In this study, a silk fibroin/gelatin (SG) gel incorporated with Mdivi-1 (SG/M) was developed and applied to chronic diabetic wounds. The SG/M hydrogel significantly enhanced diabetic wound healing compared to the plain SG hydrogel. This potential therapeutic potential of Mdivi-1 relies on promoting macrophage polarization toward the M2 phenotype and restoring hyperglycemia-mediated mitochondrial dynamic disorders and dysfunction in both macrophages and human umbilical vein endothelial cells (HUVECs) under high glucose conditions. Furthermore, Mdivi-1 facilitated mitochondrial transfer from macrophages to HUVECs, which further enhanced mitochondrial function in HUVECs and improved their cellular activity. These findings not only establish Mdivi-1 as a potential novel therapy but also provide a theoretical foundation for targeting diabetic complications, underscoring the originality and clinical relevance of this research.

Potassium ion batteries configured with organic electrode materials show promising applications due to the advantages of low cost and high theoretical capacity. Nevertheless, the design of electrolytes compatible with organic anodes and the resolution of the issue of uniform deposition of highly active potassium remain significant challenges. In this study, an engineering strategy was proposed to employ additives with electron-rich nitrile group in order to modulate the properties of ester-based electrolytes. It was found that acetonitrile (AN) can change the cation solvation structure, which determines the interfacial behavior of the K-solvent at the electrode interface, and effectively guides the homogeneous plating/stripping of K as well as suppresses dendritic growth. Therefore, a high reversible capacity of 200 mAh/g(composite) with the coulombic efficiency of 99.1 % at 50 mA/g was produced by the K-storage system of the novel phenazine anode with carbon nanotubes supported (PhAz/ CNTs) and AN-containing electrolyte. The cyano-based additive strategy may offer novel insights into the tuning of electrolyte properties for the development of high-performance potassium ion battery systems.

An important challenge in the chronic wound healing of diabetes is delayed healing stages with impaired cellular functions, attributed to mitochondrial dysfunction and excessive endoplasmic reticulum (ER) stress. Here, we describe a quercetin (QCT)-loaded zeolitic imidazolate framework (ZIF-8) incorporated into a polyphenol-mediated carboxymethyl chitosan/tannic acid (CT) dynamic hydrogel to promote diabetic wound healing by regulating subcellular and cellular functions. ZIF-8 endows the hydrogel with excellent antibacterial properties. By alleviating mitochondrial function and ER stress, the hydrogel fundamentally improves the cellular function damage induced by hyperglycemia and is endowed with reactive oxygen species (ROS)-scavenging and anti-apoptosis activities to promote cell proliferation, extension and keratinocyte differentiation. Moreover, sustained release of QCT and Zn2+ from the QCT@ZIF-8 system not only promotes vascular endothelial cell migration but also alleviates tubular dysfunction, thus achieving excellent angiogenesis. Accordingly, these features create a favorable environment for skin regeneration and synergistically accelerate diabetic wound healing. Therefore, our findings reveal a potential multi-effect therapeutic strategy for diabetic wound healing. Potential design principles targeting subcellular and cell function open up new avenues for other metabolic and inflammatory diseases.

Hydraulically amplified self-healing electrostatic (HASEL) actuators generally consisting of dielectric elastomer (DE) and transformer oil have garnered interest in the realm of soft actuators. However, existing DE can hardly reconcile contradictions between high dielectric constants and low modulus, while traditional transformer oil demands a continuous power supply to sustain strain. Herein, by incorporating liquid metal (LM) featuring high dielectric constant and low modulus, with poly(epsilon-caprolactone) (PCL) bearing low phase change temperature, a new concept of electric-thermal dual-responsive HASEL actuator is first proposed for solid-liquid bi-stabilized smart switching. It is not only able to simultaneously deliver a tripled dielectric constant of DE from 3.1 to 9.7 (at 1 kHz) and a low modulus (0.12-0.15 MPa), thus achieving a strain of 9% and a specific power of 64.8 W kg-1; but also, PCL replaces the transformer oil, acting as a "temperature switch" for the HASEL actuator, i.e., when PCL solidifies, the HASEL actuator stabilizes the deformation, allowing it to continue working even without power supply. Exemplified by valve, the as-prepared dual-responsive HASEL actuator can independently control the flow rate of each valve unit. This electric-thermal dual-responsive HASEL actuator introduces an innovative strategy for developing the next generation of multifunctional smart switching. This paper presents a new electro-thermal dual-responsive HASEL actuator, combining a dielectric elastomer and a phase change material (PCL). The Ecoflex/LM composite exhibits excellent dielectric and mechanical properties. PCL functions as a temperature switch, endowing the actuator with a solid-liquid bistable state, allowing it to remain operational without a voltage supply. image

Previous studies have shown that antimicrobial photodynamic inactivation (aPDI) can be strongly potentiated by the addition of the non-toxic inorganic salt, potassium iodide (KI). This approach was shown to apply to many different photosensitizers, including the xanthene dye Rose Bengal (RB) excited by green light (540 nm). Rose Bengal diacetate (RBDA) is a lipophilic RB derivative that is easily taken up by cells and hydrolyzed to produce an active photosensitizer. Because KI is not taken up by microbial cells, it was of interest to see if aPDI mediated by RBDA could also be potentiated by KI. The addition of 100 mM KI strongly potentiated the killing of Gram-positive methicillin-resistant Staphylocccus aureus, Gram-negative Eschericia coli, and fungal yeast Candida albicans when treated with RBDA (up to 15 µM) for 2 hours followed by green light (540 nm, 10 J/cm2). Both RBDA aPDI regimens (400 µM RBDA with or without 400 mM KI followed by 20 J/cm2 green light) accelerated the healing of MRSA-infected excisional wounds in diabetic mice, without damaging the host tissue.

Objective: Skin wound exposed to complex external environment for a long time is highly susceptible to bacterial infection. Impact Statement: This work designs a Janus adhesive dual-layer hydrogel containing in situ silver nanoparticles (named PSAP/DXP@AgNPs) with integrated attack and defense to simultaneously kill the existing bacteria and prevent foreign bacterial contamination. Introduction: The current gauze dressing fixed by tape fails to well fit at skin wound and lacks intrinsic antibacterial property, making it highly prone to causing secondary infection. Moreover, foreign bacteria may contaminate the wound dressing during use, further increasing the risk of secondary infection. Methods: In this work, a Janus adhesive dual-layer PSAP/DXP@AgNPs hydrogel is prepared by sequentially building the PSAP gel layer containing zwitterionic poly(sulfobetaine methacrylamide) (PSBMA) on the DXP@AgNPs gel layer containing in situ catechol-reduced AgNPs. Results: The flexible PSAP/DXP@AgNPs can adapt shape change of skin and adhere to skin tissue with interfacial toughness of 153.38 J m −2 relying on its DXP@AgNPs layer, which is beneficial to build favorable fit. The in situ reduced AgNPs released from the DXP@AgNPs layer of PSAP/DXP@AgNPs exhibit obvious antibacterial effects against Escherichia coli and Staphylococcus aureus , with antibacterial rates of 99% and 88%, respectively. Meanwhile, the hydrated PSAP layer of PSAP/DXP@AgNPs containing PSBMA is able to prevent the bacterial contamination, decreasing the risk of secondary infection. Besides, cell experiments demonstrate that PSAP/DXP@AgNPs is biocompatible. Conclusion: The PSAP/DXP@AgNPs hydrogel with integrated attack and defense simultaneously possessing bacteria-killing and bacteria-antifouling properties is a potential alternative in treating infected skin wound.

Glassy thermosetting polymers, which possess excellent mechanical properties, structural stability, and solvent resistance, cannot be healed and recycled due to the irreversible crosslinking network. Covalent adaptive networks could address these drawbacks, as their chemical networks are able to shuffle dynamic covalent bonds through exchange reactions, which nevertheless need high temperature or solvent assistance. Here we report a room-temperature self-healing glassy thermoset enabled by designing a disulfide-bond and H-bond hybridized network carrying abundant dangling chains, which are commonly known as network "defects." However, the "defects" do not plasticize the polymer, as they are bound to network chains through H-bonds. Therefore, the polymer possesses high modulus and strength at room temperature. Importantly, the "defects" can drive the metathesis reaction of disulfide bonds and the rearrangement of H-bonds in the glassy state, enabling the thermosetting network to self-heal at and even below room temperature.

Injectable bioadhesives are attractive for managing gastric ulcers through minimally invasive procedures. However, the formidable challenge is to develop bioadhesives that exhibit high injectability, rapidly adhere to lesion tissues with fast gelation, provide reliable protection in the harsh gastric environment, and simultaneously ensure stringent standards of biocompatibility. Here, a natural bioadhesive with tunable cohesion is developed based on the facile and controllable gelation between silk fibroin and tannic acid. By incorporating a hydrogen bond disruptor (urea or guanidine hydrochloride), the inherent network within the bioadhesive is disturbed, inducing a transition to a fluidic state for smooth injection (injection force <5 N). Upon injection, the fluidic bioadhesive thoroughly wets tissues, while the rapid diffusion of the disruptor triggers instantaneous in situ gelation. This orchestrated process fosters the formed bioadhesive with durable wet tissue affinity and mechanical properties that harmonize with gastric tissues, thereby bestowing long-lasting protection for ulcer healing, as evidenced through in vitro and in vivo verification. Moreover, it can be conveniently stored (>= 3 m) postdehydration. This work presents a promising strategy for designing highly injectable bioadhesives utilizing natural feedstocks, avoiding any safety risks associated with synthetic materials or nonphysiological gelation conditions, and offering the potential for minimally invasive application.