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As a low-density, high-strength material with high energy release potential, Al/Ep cast metal braided tubes have a wide range of application prospects in the combatant shell, which is one of the most important means to realize the integrated destructive effect of kill and blast. In this paper, Al/Ep composites with mass ratios of 3:7, 4:6 and 5:5 were prepared, and the intrinsic model of Al/Ep was established by studying its quasi-static and dynamic mechanical properties. The Al/Ep cast three-dimensional braided metal skeletons were used to obtain the required cast braided tubes with different mass ratios, and the destruction behaviors of the tubes under axial and radial compressive loads were analyzed by a combination of experimental and numerical simulations. The results show that the addition of Al particles can significantly improve the elastic-plastic properties of Al/Ep composites, and the energy storage and absorption capacities are positively correlated with the ratio of the relative contents of Al powder. When the mass ratio of Al powder to epoxy resin is 5:5, the energy absorption of Al/Ep composites is 23.16 MJ/m3, which is optimal among similar specimens and much higher than that of pure epoxy resin materials (the energy absorption of epoxy resin is 9.63 MJ/m3). The strength of binary resin matrix composites is improved, and the intrinsic models of three kinds of different mass ratios of Al/Ep composites are obtained. The intrinsic models of various Al/Ep cast braided tubes with crushing force efficiency CFE, energy absorption capacity, and specific energy absorption SEA decreased with the ratio of mass occupied by the braided filaments.

Osteoarthritis (OA), a common degenerative disease, is characterized by high disability and imposes substantial economic impacts on individuals and society. Current clinical treatments remain inadequate for effectively managing OA. Organoids, miniature 3D tissue structures from directed differentiation of stem or progenitor cells, mimic native organ structures and functions. They are useful for drug testing and serve as active grafts for organ repair. However, organoid construction requires extracellular matrix-like 3D scaffolds for cellular growth. Hydrogel microspheres, with tunable physical and chemical properties, show promise in cartilage tissue engineering by replicating the natural microenvironment. Building on prior work on SF-DNA dual-network hydrogels for cartilage regeneration, we developed a novel RGD-SF-DNA hydrogel microsphere (RSD-MS) via a microfluidic system by integrating photopolymerization with self-assembly techniques and then modified with Pep-RGDfKA. The RSD-MSs exhibited uniform size, porous surface, and optimal swelling and degradation properties. In vitro studies demonstrated that RSD-MSs enhanced bone marrow mesenchymal stem cells (BMSCs) proliferation, adhesion, and chondrogenic differentiation. Transcriptomic analysis showed RSD-MSs induced chondrogenesis mainly through integrin-mediated adhesion pathways and glycosaminoglycan biosynthesis. Moreover, in vivo studies showed that seeding BMSCs onto RSD-MSs to create cartilage organoid precursors (COPs) significantly enhanced cartilage regeneration. In conclusion, RSD-MS was an ideal candidate for the construction and long-term cultivation of cartilage organoids, offering an innovative strategy and material choice for cartilage regeneration and tissue engineering.

Segmental bone defects, stemming from trauma, infection, and tumors, pose formidable clinical challenges. Traditional bone repair materials, such as autologous and allogeneic bone grafts, grapple with limitations including source scarcity and immune rejection risks. The advent of nucleic acid nanotechnology, particularly the use of DNA hydrogels in tissue engineering, presents a promising solution, attributed to their biocompatibility, biodegradability, and programmability. However, these hydrogels, typically hindered by high gelation temperatures (∼46 °C) and high construction costs, limit cell encapsulation and broader application. Our research introduces a novel polymer-modified DNA hydrogel, developed using nucleic acid nanotechnology, which gels at a more biocompatible temperature of 37 °C and is cost-effective. This hydrogel then incorporates tetrahedral Framework Nucleic Acid (tFNA) to enhance osteogenic mineralization. Furthermore, considering the modifiability of tFNA, we modified its chains with Aptamer02 (Apt02), an aptamer known to foster angiogenesis. This dual approach significantly accelerates osteogenic differentiation in bone marrow stromal cells (BMSCs) and angiogenesis in human umbilical vein endothelial cells (HUVECs), with cell sequencing confirming their targeting efficacy, respectively. In vivo experiments in rats with critical-size cranial bone defects demonstrate their effectiveness in enhancing new bone formation. This innovation not only offers a viable solution for repairing segmental bone defects but also opens avenues for future advancements in bone organoids construction, marking a significant advancement in tissue engineering and regenerative medicine.

Summary: Patients with diabetes often experience fragile fractures despite normal or higher bone mineral density (BMD), a phenomenon termed the diabetic bone paradox (DBP). The pathogenesis and therapeutics opinions for diabetic bone disease (DBD) are not fully explored. In this study, we utilize two preclinical diabetic models, the leptin receptor-deficient db/db mice (DB) mouse model and the streptozotocin-induced diabetes (STZ) mouse model. These models demonstrate higher BMD and lower mechanical strength, mirroring clinical observations in diabetic patients. Advanced glycation end products (AGEs) accumulate in diabetic bones, causing higher non-enzymatic crosslinking within collagen fibrils. This inhibits intrafibrillar mineralization and leads to disordered mineral deposition on collagen fibrils, ultimately reducing bone strength. Guanidines, inhibiting AGE formation, significantly improve the microstructure and biomechanical strength of diabetic bone and enhance bone fracture healing. Therefore, targeting AGEs may offer a strategy to regulate bone mineralization and microstructure, potentially preventing the onset of DBD.

Background: Hyperuricemia elevates gut permeability; however, the risk of its influence on the compromised intestinal barrier is poorly understood. Aims: This study was carried out, aiming to elucidate the orchestrators and disruptors of intestinal barrier in hyperuricemia. Methods: A mouse model of hyperuricemia was induced by administering adenine and oteracil potassium to mice. Allopurinol was used to decrease uric acid level, and antibiotics were administered to mice to deplete gut microbiota. Intestinal permeability was assessed using FITC-labeled dextran. Changes in gut microbial community were analyzed through 16S rRNA sequencing. IL-1β and TNF-α levels were quantified using ELISA. The expression of tight junction protein genes, TLR4, p65 and IL-1β, was determined with Q-PCR and Western blotting. Results: Allopurinol treatment effectively reduced intestinal permeability and serum TNF-α levels. Antibiotic treatment alleviated but not abolished intestinal permeability. Uric acid alone was insufficient to increase Coca2 monolayer permeability. Allopurinol treatment altered microbial composition and suppressed opportunistic infections. Re-establishing hyperuricemia in a germfree mouse model protected mice from intestinal injury. Allopurinol and antibiotic treatments reduced TLR4 and IL-1β expressions, increased occludin and claudin-1 expressions but suppressed NF-ĸB p65 signaling. However, removing gut microbiota aggravated lipid metabolic dysfunction. Conclusion: Gut microbiota is a direct and specific cause for intestinal barrier dysfunction.

ABSTRACTIn bone tissue engineering, the search for improved repair methods is crucial, given the drawbacks of traditional strategies like donor site issues and immune rejection. Addressing these challenges, this paper introduces an innovative GelMA/Bentonite composite bioink for 3D bioprinting, designed to create scaffolds that closely emulate native bone tissue. GelMA is selected for its biocompatibility and modifiable mechanics, while Bentonite's mineral richness and ion exchange capacity are harnessed to enhance scaffold structure and promote an osteogenic microenvironment. This research marks the inaugural incorporation of Bentonite into a bioink, a significant stride forward given its established safety in pharmaceuticals and versatility across industries. This bioink formulation signifies a breakthrough in bone tissue engineering, aiming to improve the osteointegration and regeneration of bone tissue. Combining Bentonite with GelMA marks a key step in creating bioinks that enhance bone healing, potentially transforming scaffold-based bone regeneration and pioneering the use of natural nanomaterials in medicine.

The new STF impregnated Kevlar fabric coated GFRP (glass fiber reinforced polymer) composite structure obtained by combining STF（shear thickening fluid） impregnated Kevlar fabric and GFRP can obtain strong energy absorption capacity with light weight compared with two separate structures, so it has strong impact resistance. In this paper, the experiments of STF impregnated Kevlar fabric, GFRP laminated plate and STF impregnated Kevlar fabric coating GFRP laminated structure were carried out, respectively. Based on reliable numerical simulation, the macroscopic damage and energy absorption characteristics of the same material in STF impregnated Kevlar fabric, GFRP laminated plate and STF impregnated Kevlar fabric coating GFRP laminated structure were analyzed. The results show that the GFRP laminate and the rear Kevlar fabric in the STF-impregnated Kevlar fabric coating GFRP laminate structure show a larger damage area than that of GFRP laminate and STF impregnated Kevlar fabric alone, and a larger deflection is generated during the process of impact. The increase of the number of layers of Kevlar fabric in the front and back of the laminate and the increase of the thickness of the laminate make the Kevlar fabric absorb more energy. If the energy absorption capacity of GFRP laminates is increased, the number of layers of the front Kevlar fabric can be reduced, the thickness of the laminates can be increased, and materials with greater strength can be added to the front ply of the laminates. However, increasing the thickness of GFRP laminates will reduce the lightweight requirements of laminated structures.

In this study, the properties of controlled low strength material (CLSM) made from waste soil were examined, utilizing 53 different mix proportions, and a dataset was subsequently constructed. Models, such as particle swarm optimization (PSO)-support vector regression (SVR), genetic algorithm (GA)-SVR, and grid search (GS)-SVR, were developed to predict both flowability and unconfined compressive strength (UCS). To assess the models’ performance, comparisons between experimental and predicted values, residual distribution histograms, and evaluation criteria were conducted. Results revealed that all three models effectively predicted the flowability and UCS of CLSM made from waste soil. Predicted values closely aligned with experimental values in both training and testing sets. Notably, GA-SVR exhibited greater accuracy when compared to PSO-SVR and GS-SVR. Evaluation criteria, including correlation coefficient (R2), mean square error (MSE), root mean square error (RMSE), mean absolute error (MAE), and mean absolute percentage error (MAPE) for GA-SVR in assessing flowability were 0.948, 77.899, 8.826, 7.608, and 3.061 %, respectively. Correspondingly, for UCS, the values were 0.934, 0.032, 0.178, 0.115, and 8.956 %, respectively. Furthermore, the histogram depicting the residual distribution of the GA-SVR model closely resembled a normal distribution, characterized by a small mean and standard deviation. Extending the analysis to 45 compression strength data points obtained from public literature, the three models continued to demonstrate effective predictive capabilities, with the GA-SVR model outperforming the others. The evaluation criteria, including R2, MSE, RMSE, MAE, and MAPE in this context were 0.909, 0.011, 0.105, 0.085, and 15.502 %, respectively. Shapley additive explanation (SHAP) values highlighted water as the most crucial input variable in the flowability model. Additionally, water, superplasticizer (SP), and sand positively impacted flowability, whereas soil, fly ash (FA), and cement exerted negative effects. In the UCS model, curing age (CA) emerged as the most important input variable. CA, cement, FA, sand, and soil positively influenced UCS, while water and SP had negative effects. This study is of considerable importance in the accurate prediction and evaluation of CLSM engineering properties, as well as in optimizing mix proportions.

Traditional hydrogel design and optimization methods usually rely on repeated experiments, which is time-consuming and expensive, resulting in a slow-moving of advanced hydrogel development. With the rapid development of artificial intelligence (AI) technology and increasing material data, AI-energized design and optimization of hydrogels for biomedical applications has emerged as a revolutionary breakthrough in materials science. This review begins by outlining the history of AI and the potential advantages of using AI in the design and optimization of hydrogels, such as prediction and optimization of properties, multi-attribute optimization, high-throughput screening, automated material discovery, optimizing experimental design, and etc. Then, we focus on the various applications of hydrogels supported by AI technology in biomedicine, including drug delivery, bio-inks for advanced manufacturing, tissue repair, and biosensors, so as to provide a clear and comprehensive understanding of researchers in this field. Finally, we discuss the future directions and prospects, and provide a new perspective for the research and development of novel hydrogel materials for biomedical applications.

IntroductionThe intricate interplay between gut microbiota and hyperuricemia remains a subject of growing interest. However, existing studies only provided snapshots of the gut microbiome at single time points, the temporal dynamics of gut microbiota alterations during hyperuricemia progression and the intricate interplay between the gut barrier and microbiota remain underexplored. Our investigation revealed compelling insights into the dynamic changes in both gut microbiota and intestinal barrier function throughout the course of hyperuricemia.MethodsThe hyperuricemia mice (HY) were given intragastric administration of adenine and potassium oxalate. Gut microbiota was analyzed by 16S rRNA sequencing at 3, 7, 14, and 21 days after the start of the modeling process. Intestinal permeability as well as LPS, TNF-α, and IL-1β levels were measured at 3, 7, 14, and 21 days.ResultsWe discovered that shifts in microbial community composition occur prior to the onset of hyperuricemia, key bacterial Bacteroidaceae, Bacteroides, and Blautia exhibited reduced levels, potentially fueling microbial dysbiosis as the disease progresses. During the course of hyperuricemia, the dynamic fluctuations in both uric acid levels and intestinal barrier function was accompanied with the depletion of key beneficial bacteria, including Prevotellaceae, Muribaculum, Parabacteroides, Akkermansia, and Bacteroides, and coincided with an increase in pathogenic bacteria such as Oscillibacter and Ruminiclostridium. This microbial community shift likely contributed to elevated lipopolysaccharide (LPS) and pro-inflammatory cytokine levels, ultimately promoting metabolic inflammation. The decline of Burkholderiaceae and Parasutterella was inversely related to uric acid levels, Conversely, key families Ruminococcaceae, Family_XIII, genera Anaeroplasma exhibited positive correlations with uric acid levels. Akkermansiaceae and Bacteroidaceae demonstrating negative correlations, while LPS-containing microbiota such as Desulfovibrio and Enterorhabdus exhibited positive correlations with intestinal permeability.ConclusionIn summary, this study offers a dynamic perspective on the complex interplay between gut microbiota, uric acid levels, and intestinal barrier function during hyperuricemia progression. Our study suggested that Ruminiclostridium, Bacteroides, Akkermansiaceae, Bilophila, Burkholderiaceae and Parasutterella were the key bacteria that play vital rols in the progress of hyperuricemia and compromised intestinal barrier, which provide a potential avenue for therapeutic interventions in hyperuricemia.

Skeletal muscle disorders have posed great threats to health. Selective delivery of drugs and oligonucleotides to skeletal muscle is challenging. Aptamers can improve targeting efficacy. In this study, for the first time, the human skeletal muscle-specific ssDNA aptamers (HSM01, etc.) were selected and identified with Systematic Evolution of Ligands by Exponential Enrichment (SELEX). The HSM01 ssDNA aptamer preferentially interacted with human skeletal muscle cells in vitro. The in vivo study using tree shrews showed that the HSM01 ssDNA aptamer specifically targeted human skeletal muscle cells. Furthermore, the ability of HSM01 ssDNA aptamer to target skeletal muscle cells was not affected by the formation of a disulfide bond with nanoliposomes in vitro or in vivo, suggesting a potential new approach for targeted drug delivery to skeletal muscles via liposomes. Therefore, this newly identified ssDNA aptamer and nanoliposome modification could be used for the treatment of human skeletal muscle diseases.

The low flexoelectric coefficients of polymers are the key problem that limit their application. In this paper, electret-like PDMS/metal conductive layer/PDMS laminated structures have been prepared, an internal electric field are applied on the metal conductive layer aimed at improving electromechanical response. Experiments on the flexoelectric responses of polymer laminated structures under impact are performed based on SHPB, in-layer voltage supply system and polarization voltage measuring system. Numerical simulations are also conducted to investigate the dynamic stress-strain relationship and polarization characteristics of polymer laminated structure under different in-layer voltages. The results show that maximum stress increases with decreasing in-layer voltage; the maximum polarization voltage increases first and then decreases with absolute value of in-layer voltage; the minimum polarization voltage decreases with absolute value of in-layer voltage. Specimen with negative voltage has advantage of conversing electric energy and transferring charges. The impact induced strain gradients have been investigated based on numerical simulation and the related flexoelectricity coefficients are obtained. Addition of metal conductive layer and application of in-layer voltage are effective ways to enhance flexoelectricity.

Type 2 diabetes mellitus (T2DM) and T2DM-related complications [such as retinopathy, nephropathy, and cardiovascular diseases (CVDs)] are the most prevalent metabolic diseases. Intriguingly, overwhelming findings have shown a strong association of the gut microbiome with the etiology of these diseases, including the role of aberrant gut bacterial metabolites, increased intestinal permeability, and pathogenic immune function affecting host metabolism. Thus, deciphering the specific microbiota, metabolites, and the related mechanisms to T2DM-related complications by combined analyses of metagenomics and metabolomics data can lead to an innovative strategy for the treatment of these diseases. Accordingly, this review highlights the advanced knowledge about the characteristics of the gut microbiota in T2DM-related complications and how it can be associated with the pathogenesis of these diseases. Also, recent studies providing a new perspective on microbiota-targeted therapies are included.

Aluminum honeycomb framework reinforced Al/PTFE material is a kind of high inert energetic material, which has higher strength and structure advantages than that of pure Al/PTFE material. In order to meet the requirements of special penetration/blasting performance, this paper adds aluminum honeycomb framework with arm length of 1.5 mm into the traditional formula Al/PTFE (mass percentage of Al and PTFE is 26.5% and 73.5%). The energetic material reinforced by aluminum honeycomb framework (20.5% Al/73.5% PTFE/6% aluminum honeycomb) is obtained by cold pressing sintering，and the experimental evaluation of release energy generated by high velocity impact in vacuum was performed by using two-stage light gas gun loading system, transient optical fiber pyrometer measurement system, overpressure measurement system and infrared thermal imager measurement system. Experimental results show that the impact reaction temperature is about 700 °C in vacuum in the velocity range of 0.96–1.5 km/s, and the energy release of the specimen increases with the increase of impact velocity. When the impact velocity is greater than 1.5 km/s, the specimen fully reacts, and the energy released by the complete reaction of the specimen does not exceed 8.3 kJ/g.

To profoundly reveal the protective performance of CFRP/aluminum foam sandwich structure, the high-speed impact simulation models of CFRP, aluminum foam and their sandwich structures are built by ABAQUS/Explicit module. The VUMAT user material subroutine is written for CFRP panel, and Hashin damage criterion is introduced. The elastic constitutive model and macro modeling method for the aluminum foam are chosen. The impact process under different working conditions is numerically simulated and the reliability of the model is verified by one-stage light gas gun loading experiment at the corresponding simulation conditions. At the same time, the protective performance of CFRP/ aluminum foam sandwich structure under different steel projectile shapes, impact velocities and impact angles (the angle between the ballistic and the target normal line) are simulated. The results show that the Mises stress nephogram of CFRP panel is peanut-like with obvious directivity. The stress wave propagates fastest in the direction perpendicular to the fiber. In the impact velocity range of 172−450 m/s, with the increase of impact velocities, the loss of kinetic energy will increase, but the increase of kinetic energy loss will decrease with the increase of impact velocities, and the contact force between the projectile and the sandwich structure will also increase. Thus the sandwich structure will have more serious delamination and fiber breakage, which will consume more kinetic energy. When the velocity of the projectile is greater than 300 m/s, the impact capability of the sandwich structure tends to the upper limit of impact capacity. In the impact velocity range of 170∼300m/s, the sandwich structure has stronger protective performance than ball-nosed projectile when the flat-nosed projectile impact, and the difference of the residual velocity between the two kinds of projectiles is larger. The shape of the projectile has a great influence on the protective performance of the CFRP/ aluminum foam sandwich structure. When the impact velocity is greater than 300m/s, the residual velocities of the two kinds of projectiles are almost the same, and the shapes of the projectile have a gradual effect on the performances of the CFRP/ aluminum foam sandwich structure. The anti-shock performance of sandwich structure under oblique impact is stronger than that of vertical impact. With the increase of impact angles, the transverse deformation of sandwich structure increases, and the anti-shock performance of sandwich structure also increases.

The structures composed by metal fiber and auxiliary elastomer are stretchable and have potential application under larger strain. Nowadays, interfacial failure is still the key problem affecting practicability of the structures. The result of typical pull-out test indicates that three stages exist in this pull-out process: elastic deformation, interfacial debonding and interfacial friction. For the sake of determination of interfacial parameters, a numerical method has been proposed to characterize the damage initiation point by using the slope of force-displacement curve of pull-out experiment. Furthermore, based on the basic material and interfacial parameters, extensive simulations have been conducted to study parametric effect on the general mechanical behavior of structures, including interfacial elastic modulus, failure strength and damage evolution law and friction. The results indicate both interfacial cohesive and friction contribute to the force increasing after damage initiation points.

To investigate the dynamic compressive behavior of zirconium filaments/aluminum/polytetrafluoroethylene (mass fraction of Zr fiber/Al/PTFE of 3%/23.5%/73.5%) active materials, traditional formula Al/PTFE active materials (Al/PTFE mass fraction of 26.5%/73.5%) and Al/Zr/PTFE active materials were prepared by cold pressing sintering process. The microscopic morphology and impact reaction behavior of the material by scanning electron microscopy (SEM) and high-speed camera are observed. The dynamic compressive experiments of the two materials are carried out by using separate Hopkinson bar (SHPB) test system. The results show that the Al/PTFE by adding active metal zirconium (Zr) filaments can improve the dynamic compressive properties of conventionally Al/PTFE. The failure strength of active material is increased from 32 MPa to 110 MPa comparing with conventionally Al/PTFE active materials, and the increase is about 243.75%. When the strain rate is 2500–4000 s−1, Al/Zr/PTFE specimens exhibit the same elastic–plastic mechanical behavior as conventionally Al/PTFE specimens. The behavior of the two specimens can also be divided into three stages: compressive deformation, crack generation and hot spot initiation (there are microscopic holes around Zr fibers, and the collapse and expansion of holes is the main reason for the formation of hot spots).

In view of the wide demands of sandwich structure with aluminum honeycomb material as core layer in many important fields such as automobile manufacturing, transportation, aerospace, protection engineering as well as ship, etc. In order to reveal the interacting duration and microscopic characteristics generated by high-velocity impact on Carbon Fiber Reinforced Plastics/Aluminum honeycomb core sandwich panel (CFRP/Al HC SP), a series of experiments about combined type and split type targets impacted by cylindrical steel projectiles at the velocity of nearly 300m/s have been performed by using one-stage light gas loading system and related velocity measurement systems established by ourselves. The residual velocities and the interacting duration are measured during the process of the projectile piercing through combined type target and each part of the split target, respectively. Meanwhile, the simulations have been conducted under the corresponding experimental conditions, and the microscopic characteristics of the CFRP specimens have also been analyzed by using scanning electron microscopy (SEM). The results shows that the total interacting duration on the whole combined type structure is 164.5 μs, and duration consumed in the front CFRP panel, Al HC and the rear CFRP panel in combined target are 32.5 μs, 91.7 μs and 40.3 μs, respectively. The damage morphology, residual velocity and interacting duration in each parts of the combined type target obtained by numerical simulation of ABAQUS/Explicit module are basically consistent with the experiments, and the crack, delamination, fracture and drawing wire of carbon fiber filaments have been given by cylindrical solid steel projectile impacting on CFRP panel at the given experimental conditions. Keywords: High-velocity impact, CFRP/Al HC SP structure, Interacting duration, ABAQUS/Explicit module, Microscopic characteristics

In order to deeply reveal the microscopic damage mode and microscopic damage mechanism of Carbon Fiber Reinforced Plastic laminates (CFRP laminates) impacted vertically by the ice projectile at high velocity. In this paper, the loading system of the one-stage light gas gun, the liquid nitrogen circulating cooling system, the impact pressure measuring system and the high speed camera acquisition system are used, and the experiments of the spherical ice projectile (simulated hail ice, SHI) with diameter of 11 mm impacting CFRP laminates vertically at the velocity of 50-200 m/s were carried out. The impact pressure of the SHI impacting the target, the strain of X-Y in the two main directions at the impact point were measured, and the deflection/ time history curve at the impact point during the impact process was obtained. By using ABAQUS/Explicit finite element software, the numerical simulation of high-velocity vertical impact of SHI on CFRP laminates was compared with the image acquisition results of the high speed camera at different moments during the impact process, and the failure morphology and process of SHI was analyzed. At the same time, the delamination of the target obtained by numerical simulation is compared with the cracking of the CFRP fiber reinforcement and the delamination of the epoxy resin interface obtained by microscopic SEM observation, the correctness of using cohesion model to describe the micro-damage of CFRP laminates induced by SHI impacting vertically at high speed was verified. The damage failure threshold of CFRP laminates under the impact load of SHI under given experimental conditions was obtained. By establishing a three-point simply supported physical model, the ultimate deflection of laminated plates subjected to delamination failure was analyzed. Based on the measurement of strain and deflection at impact point, the valuable reference for the prediction of delamination failure in CFRP laminates can be provided, then the detection of the micro-damage to the surface composite part of the aircraft will be realized by the control of the sensor. Keywords: CFRP laminates, Cohesion model of ice projectiles, Microscopic damage model, Microscopic damage mechanism, Delamination failure prediction

Aluminum/Polytetrafluoroethylene (Al/PTFE) reactive material occurs chemical reaction and release a large amount of energy under the impact load, which has the dual characteristics of strength and energy release, so it can be applied to the attack of confined space targets to enhance the damage effect on the target. In order to study the dynamic strength of enhanced Al/PTFE and the real-time impact release energy, based on the traditional formula Al/PTFE (26.5%/73.5%), enhanced Al/PTFE reactive material specimens were prepared by cold pressing and rapid cooling processes, and the dynamic mechanical properties of the specimens were tested by the Split Hopkinson Pressure Bar (SHPB) testing system. The experiments have been conducted by using two-stage light gas gun loading system combining with the impact release energy related testing system under vacuum condition. Meanwhile, the evolutionary process of reaction product was numerically simulated by ANSYS/Fluent, and the boundary conditions of the numerical simulation were defined by self-programmed UDF subroutine. Experiments, theoretical analysis and numerical simulation were adopted to obtain the real time energy release of Al/PTFE reactive materials at different impact velocities. The results show that the maximum dynamic failure strength of the enhanced Al/PTFE reactive projectile is 126 MPa, and the strain rate hardening phenomenon and viscoelastic effect are exhibited when the strain rate is in the range of 1500 ∼ 3000 s−1. When the strain rate is in the range of 3000 ∼ 4000 s−1, the specimen is insensitive to strain rate. When the impact velocities are 2.30 km/s and 2.54 km/s, the energies that the reactive projectiles release are 8.36 kJ/g and 8.38 kJ/g, respectively, and the reactive material reacts completely. When the impact velocities are 1.64 km/s, 1.80 km/s and 1.94 km/s, the projectiles have not fully reacted. The reactive degree of the reactive projectile increases with the increase of the impact velocity. For the complete reaction of Al/PTFE reactive projectile, the critical impact velocity of the enhanced reactive material is between 1.94 km/s and 2.30 km/s.

In order to clarify the electromechanical coupling characteristics of polymer materials and extend their applications in MEMS (Micro-electromechanical Systems), electromechanical responses of PDMS (Polydimethylsiloxane) with different electrodes and thicknesses under different loading conditions have been performed experimentally and numerically. Basic electrical parameters measurement and quasi-static tensile experiment of PDMS specimens were conducted. Furthermore, the dynamic mechanical properties and polarization voltage of PDMS with different electrodes and thicknesses under different loading conditions have been studied by Split Hopkinson Pressure Bar (SHPB) system integrating with electrical output measuring system. Beyond that, Abaqus/Explicit numerical simulation of PDMS specimen under different loading conditions was carried out based on Yeoh viscoelastic model and Prony series, then the strain gradient and the flexoelectric coefficients were obtained. The results show that the maximum stress of PDMS increases with increasing of loading speed and decreases with increasing of thickness, the maximum polarization voltage increases with increasing of strain rate, the maximum polarization voltages of PDMS with “C” electrode and “+” electrode are about 14 times of that with circular electrode, the flexoelectric coefficients of PDMS are within the range of 10−11–10−9C/m.

In view of the wide demands of sandwich structure with porous material as core layer in many important fields such as protection engineering, aerospace, automobile manufacturing and ship, etc. In order to reveal the energy absorption and damage characteristics of high velocity impact aluminum foam core and CFRP/aluminum foam core structure, the quasi-static loading system, one-stage light gas gun loading system, the impact pressure testing system and the high-speed camera acquisition system were used to perform the quasi-static compression experiments of aluminum foam and the projectiles with different materials impacting on the aluminum foam core and CFRP/aluminum foam sandwich structure at the speeds of 100–300 m/s. The influences of impact velocity and projectile’ density on the damage characteristics of CFRP/aluminum foam sandwich structure and the attenuation effect of shock wave in sandwich structure have been studied. The experimental results showed that the curve of stress and strain has three typical zones similar to porous materials: elastic zone, yield platform zone and compaction zone under quasi-static compression loading. Due to its brittle and low tensile strength of aluminum foam material, the single aluminum foam plate has poor ballistic performance under the high-speed impact of projectiles with different materials. Therefore, closed cell aluminum foam needs to be combined with high strength panels to form sandwich structure to improve its ballistic performance. Keywords: High velocity impact, Aluminum foam core, CFRP/aluminum foam sandwich structure, Energy dissipation, Damage characteristics

Active electromagnetic armor, as a kind of electromagnetic launch, is a future-oriented high-tech weaponry. The geometric parameters of the coil are the key elements affecting the interception performance. In this paper, the influence of copper strip length, copper strip thickness and radius of the base circle on the initial launch velocity of the intercepting plate was studied based on the self-developed launcher. The relationship between the length of the copper strip and the initial velocity was theoretically deduced. The reliability of the simulation was verified by a combination of simulation and experiment. The results show that the initial velocity of the intercepting plate is linear with the winding length of the coil. As the width of the copper strip increases, the initial velocity increases accordingly, and the radius of the base circle has little effect on the initial velocity of intercepting plate.

The spherical ice projectile impacting vertically on Carbon Fiber Reinforced Plastic laminates (CFRP laminates) with different curvatures was developed by using the one-stage light gas gun loading system. The numerical simulation results of the vertical impact of the arched CFRP laminates with different curvatures by SHI were compared with the experimental test results, Scanning Electron Microscopy micro failure mode and the image acquisition of the high speed camera by using ABAQUS/Explicit finite element software. The deformation process and failure mode of arched CFRP laminates with different curvatures and simulated hail ice (SHI)were analyzed, and the reliability of the numerical simulation was verified. By establishing a two-hinged simply supported mechanical physical model of arched laminates, the principal stresses of each layer along the direction of 0° and 90° of fibers in arched laminates were obtained. It would provide technical support for the prediction of fiber failure and delamination damage in the process of impacting on laminates at high velocity.

To investigate the relationship between stress wave propagation and the plasma discharge generated by a projectile high-velocity impact on solar array with 2A12 aluminum substrate structures at the incidence angle of 60°. Three sets of experiments about stress wave propagating and plasma discharge in composite structure of solar array have been performed by taking advantage of PVDF (polyvinylidene fluoride) film sensor, plasma characteristic parameter diagnostic system, discharge measurement system and two-stage light gas gun loading system established by ourselves. Experimental results showed that the duration of stress wave was about 30±5μs, and maximum stresses are about 1400±200MPa in experiments. Furthermore, the discharge phenomenon did happen and the duration of discharge current was also different in solar array at the different impact velocities. The basic consistency between stress wave propagation and discharge duration is also confirmed by experiments.

Plasma-induced discharge is an important effect on the solar array of orbiting space vehicles subjected to hypervelocity impact, which will pose a serious threat to the power supply system of spacecraft. The paper investigates experimentally the process that the projectile in various impact velocities and incidence angles impact on solar array with sandwich structure comprising of a coverglass, a silica gel and a 2A12 aluminum liner at the different positions. The electron temperature and density of the plasma were diagnosed by applying in independent-constructed Triple Langmuir Probe diagnostic system, meanwhile, the charging and discharge test system were also constructed by ourselves. Three sets of experiments have been performed by two-stage light gas gun loading system and related measurement system. Especially, residual velocity was measured when projectile pierced through the solar array with composite structure. Experimental results revealed the discharge causes based on stress wave theory, and the discharge current characteristics of a primary and a secondary discharge of solar array induced by hypervelocity impact were given through hypervelocity impact experiments. Finally, it will provide a valuable benchmark for the construction of solar array against space debris.

Due to the actual situation of spacecraft surface’ charging, such as convex corners, weld line, whalebone and a multiple-interfaces with different materials, all these are main factors leading to uneven charging of spacecraft surface, even creating gradient potential. If the charging spacecraft surface is impacted by debris or micrometeor, discharge effect induced by impacting will pose a serious threat to spacecraft in orbit. So realizing spacecraft charging surface with different potential differences and grasping discharge characteristics are a decisive importance at the different experimental conditions in laboratory. To simulate the spacecraft surface with a gradient potential in laboratory, spacecraft surface is split into different parts, which different gaps reserved in 2 adjacent surface is added resistance to create different potential surfaces, and the high potential surface as a impact target in the split targets. Charging circuit system realizing different gradient potential and discharge test system are built by ourselves, combining with two-stage light gas gun loading system, six sets of experiments have been performed about hypervelocity impact on 2A12 aluminum split targets with gradient potentials. In the experiments, gaps of 2A12 aluminum target are the same among different parts in every experiments, the gaps of the split targets are 2mm, 3mm, 5mm, 7mm and 10mm in the experiments, respectively. And the applied voltage is 300V in all the experiments and high-potential 2A12 aluminum plate as the impact target. The experiments have been performed at the impact velocity of about 3km/s and the incidence angles of 60o and 90o (between projectile flying trajectory and target plane), respectively. Voltage probe and current probes are used for acquiring discharge voltages and currents during the process of the impact. The experimental results showed that the discharge induced by impact plasma were generated among high and low-potential target by forming a plasma discharge channel. With the increasing of the gaps among the high and low-potential targets, the peak values of the discharge current decreased first then increased. When the gaps of split targets reached a certain value, the peak values of the discharge current decreased again. Meanwhile, the gaps among high and low-potential targets was 5mm, the peak value of the discharge current was the smallest. With the increasing of the gaps among the split targets, a primary discharge duration also increased. However, when the gaps among the split targets were greater than 5mm, increasing trend of discharge duration would slow down. When the gaps among the split targets were greater than 7mm, there was a secondary discharge phenomenon, and the physical explanations were given about the influence of different gaps among the split targets on the discharge effects created by hypervelocity impact.

Urban mobility significantly contributes to global carbon dioxide emissions. Given the rapid expansion and growth in urban areas, cities thus require innovative policies to ensure efficient and sustainable mobility. Urban typologies can serve as a vehicle for understanding dynamics of cities, which exhibit high variability in form, economic output, mobility behavior, among others. Yet, typologies relevant for sustainable urban mobility analyses are few, outdated and not large enough in scope. In this paper, we present a new typologization spanning 331 cities in 124 countries. Our sample represents 40% of the global urban population and contains the most recent data from 2008 to date. Using a factor analytic and agglomerative clustering approach, we identify 9 urban factors and 12 typologies. We discuss the implications of this new framework for researchers and planners and investigate the relationships between mobility and environmental sustainability indicators. Notably, we show an immediate application of the urban typologies to better understanding travel behavior and also describe their usage for detailed large-scale simulation in representative prototype cities for insights into sustainable future mobility policy pathways. Our data and results are publicly available for further exploration and will serve as a foundation for future analyses toward desirable urban and environmental outcomes.

Introduction: The intricate interplay between gut microbiota and hyperuricemia remains a subject of growing interest. However, existing studies only provided snapshots of the gut microbiome at single time points, the temporal dynamics of gut microbiota alterations during hyperuricemia progression and the intricate interplay between the gut barrier and microbiota remain underexplored. Our investigation revealed compelling insights into the dynamic changes in both gut microbiota and intestinal barrier function throughout the course of hyperuricemia. Methods: The hyperuricemia mice (HY) were given intragastric administration of adenine and potassium oxalate. Gut microbiota was analyzed by 16S rRNA sequencing at 3, 7, 14, and 21 days after the start of the modeling process. Intestinal permeability as well as LPS, TNF-a, and IL-1ß levels were measured at 3, 7, 14, and 21 days. Results: We discovered that shifts in microbial community composition occur prior to the onset of hyperuricemia, key bacterial Bacteroidaceae, Bacteroides, and Blautia exhibited reduced levels, potentially fueling microbial dysbiosis as the disease progresses. During the course of hyperuricemia, the dynamic fluctuations in both uric acid levels and intestinal barrier function was accompanied with the depletion of key beneficial bacteria, including Prevotellaceae, Muribaculum, Parabacteroides, Akkermansia, and Bacteroides, and coincided with an increase in pathogenic bacteria such as Oscillibacter and Ruminiclostridium. This microbial community shift likely contributed to elevated lipopolysaccharide (LPS) and proinflammatory cytokine levels, ultimately promoting metabolic inflammation. The decline of Burkholderiaceae and Parasutterella was inversely related to uric acid levels, Conversely, key families Ruminococcaceae, Family_XIII, genera Anaeroplasma exhibited positive correlations with uric acid levels. Akkermansiaceae and Bacteroidaceae demonstrating negative correlations, while LPS-containing microbiota such as Desulfovibrio and Enterorhabdus exhibited positive correlations with intestinal permeability. Conclusion: In summary, this study offers a dynamic perspective on the complex interplay between gut microbiota, uric acid levels, and intestinal barrier function during hyperuricemia progression. Our study suggested that Ruminiclostridium, Bacteroides, Akkermansiaceae, Bilophila, Burkholderiaceae and Parasutterella were the key bacteria that play vital rols in the progress of hyperuricemia and compromised intestinal barrier, which provide a potential avenue for therapeutic interventions in hyperuricemia. [ABSTRACT FROM AUTHOR]

To introduce the application background the selfpowered technology for Fuze bridge fire, high overload microthermal battery activation, rocket ignition, and the aircraft escape actual condition lifesaving system ignition power supply, which intends to use the high-speed impact of piezoelectric ceramic in the process of missile launching high overload pressure or missile and target intersection in the process of high overload stress wave of piezoelectric ceramics and the transformation of power, for closer to confession technology for Fuze bridge ignition, high overload microthermal battery activation, rocket ignition, and aircraft escape system engineering problems. The stress wave propagation in the PZT-5H piezoelectric ceramic composite target and load resistance effect to the electrical output characteristics is investigated under the strong shock loading; the experiments have been performed about cylindrical steel projectiles normal impact on PZT-5H piezoelectric ceramic composite target by using polyvinylidene fluoride stress test system and electrical output test system combining with one-stage light gas gun loading system. The experimental results show that the stress duration and peak stress are about 9 μs and 232 MPa, respectively, when the cylindrical projectile impacts on piezoelectric ceramic composite target at the impact velocity of 345 m/s. The outputs of current pulse peak, voltage pulse peak, and energy peak are 20 A, 734 V, and 11 mJ under the stress interactions of 200-300 MPa. At the near-impact stress conditions, the electrical output characteristics of piezoelectric ceramics are greatly affected by the load resistance. The output voltage pulse increases with the increasing of load resistance value, and the values of the load resistance have a significant effect on output energy; output energy conversion rate is up to 82% when the load resistance is 50 Ω. [ABSTRACT FROM AUTHOR]

To investigate the light flash intensity and spectral characteristics produced by high-velocity impact on solar array at the same projectile incidence angles and the different impact velocities, the experimental measurements of light flash and the spectral radiant intensity, for 2A12 aluminum projectile high-velocity impact on solar array, have been conducted through an measurement system of optical transient pyrometer, spectral acquirement system and ultra-high speed camera system by using two-stage light gas gun loading system at the different impact velocities and 45° incidence angle of the projectile. Experimental results show that the peak values of the light flash intensity is the biggest at the wavelength of 600 nm among the wavelengths of 550 nm, 600 nm, 650 nm and 700 nm during 2A12 aluminum projectile high-velocity impact on solar array at the given experimental conditions. And variations of light flash from the optical transient pyrometer and the photographs acquired by the ultra-high speed camera are synchronous. Meanwhile, the relationships of spectral radiant intensity were given about material's elemental compositions of the projectile and target with impact velocities in the paper. Spectral signatures created by high-velocity impact can be utilized as the basis for deep space exploration, which can characterize the material's elemental compositions of the projectile and target. [ABSTRACT FROM AUTHOR]

Rnf2 is a fundamental component of the polycomb repressive complex 1and acts as the really interesting new gene finger E3 ligase, which is responsible for histone 2A modification. Previous studies have shown that the ring finger protein 2 (Rnf2) is overexpressed in various types of tumor and has a close association with tumor development. However, few studies have been carried out into the expression and biological function of Rnf2 in gastric cancer cells. The present study measured the expression of Rnf2 in gastric cancer cells and normal epithelial gastric cells. The results demonstrate that Rnf2 is upregulated in gastric cancer cells. In addition, the knockdown of Rnf2 inhibited the cell viability and induced increased G1 phase followed by a substantial reduction of the G2/M phase. The expression levels of p21 and p27 were also significantly elevated by the knockdown of Rnf2. These results provide evidence of the oncogenic function of Rnf2 in gastric cancer, possibly through an inhibition of cellular proliferation and a delay of the G2/M phase. Therefore, Rnf2 may be a novel target for the prognosis and therapy of gastric cancer. [ABSTRACT FROM AUTHOR]

The purpose of the paper is to investigate the discharge of the plasma generated by a projectile hypervelocity impact on solar array with three kinds of different substrates at the 60◦ incidence angle and the external applied voltage of 100 voltage. Four sets of experiments were performed to impact solar arrays with CFRP Aluminum honeycomb sandwich substrate, Aluminum honeycomb sandwich substrate and the aluminum substrate by using two-stage light gas gun loading system and discharge measurement system established. Experimental results showed that discharge voltage and discharge current of the solar array with CFRP Aluminum honeycomb sandwich substrate are the most strongest among the solar array with CFRP Aluminum honeycomb sandwich substrate, Aluminum honeycomb sandwich substrate and the aluminum substrate. This work will be helpful to improve the material and substrate' structure of the solar arrays in spacecrafts. [ABSTRACT FROM AUTHOR]

In order to understand luminous efficiency of the visible wavelength and the infrared wavelength range generated by hypervelocity impact natural dolomite plate, experimental measurement of the light flash created by hypervelocity impact natural dolomite plate were performed in the visible wavelength range by using the optical transient pyrometer measurement system and two-stage light gas gun loading system at the different impact velocity and the projectile incident angles of 45엯 and 60엯 (with the angle along the target plane), respectively. Based on the Planck's blackbody continuous radiation law in the visible wavelength range, luminous efficiency extrapolate to infrared wavelength range by combining with Matlab computer programming, the calculated results of the luminous efficiency showed that the luminous efficiency of the light flash created by hypervelocity impact natural dolomite plate in the infrared wavelength range was approximately 1∼1.5 times in the visible wavelength range. [ABSTRACT FROM AUTHOR]

• 1 Expertments on SiC and C/SiC projectiles impacting on C/SiC composites perpendicularly using impact velocities ranging from 1.35 km/s to 3.5 km/s were carried out. • 2 The thermal and dynamic response characteristics were analyzed comprehensively based on flash radiant intensity and temperature, impact pressure and morphological characteristics induced by SiC and C/SiC projectile impacting on C/SiC composites. • 3 The influence laws of impact conditions on the flash radiant characteristics and the damage characteristics of the target plates are given, and the differences of thermal and dynamic response between the two kinds of projectiles were compared. Continuous carbon fiber-reinforced SiC-matrix composites(C/SiCs) have been developed for key thermal structures of aerospace and hypersonic vehicles, which is important to research on thermal and dynamic behavior of C/SiC composites under hypervelocity impact for understanding the response characteristics of C/SiC composites subjected to shock loading. The projectiles made of C/SiC composites and silicon carbide(SiC) were loaded by two-stage light gas gun to impact C/SiC plates with impact velocities from 1.35 km/s to 3.5 km/s and impact angle of 90°, the damage morphology of C/SiC plates, the evolutionary process of thermal radiation and impact pressure were obtained. The experimental results show that fiber failure of C/SiC composites consumes part of the initial kinetic energy during hypervelocity impact, therefore, the carbon fiber improves the fracture toughness of SiC matrix. Under the experimental conditions given in this paper, the lower impact velocity is, the greater differences of thermal and dynamic response between the two kinds of projectiles are. Compared with SiC projectiles, the C/SiC composite projectiles have longer flash radiant duration and lower flash radiant temperature. However, when the impact velocity is higher, the flash radiant duration and the flash radiant temperature of the two kinds of projectiles are similar due to the fiber fracture of the C/SiC composite, and the peak of flash radiant temperature appears before flash radiant intensity during impact process. For the damage characteristics of C/SiC plates, the higher impact velocity is, the smaller perforation diameter of C/SiC plates is, and the shape is more regular. With the decrease of the impact velocity, the damage morphology of C/SiC plates is irregular, and the matrix powdering is more serious. [ABSTRACT FROM AUTHOR]