This review examines the impact of ionizing radiation on bone microstructure and mechanical properties in murine models, with particular attention to how different radiation types, total absorbed doses, and dose rates influence skeletal tissue. The topic is highly relevant in both radiotherapy and aerospace research, two different scenarios but that share important skeletal consequences, such as disturbances in bone remodeling, deterioration of trabecular and cortical microarchitecture, and reductions in mechanical strength.
Methods: This review was conducted following PRISMA guidelines, with a structured search across Scopus, PubMed, and Google Scholar using predefined keywords and Boolean operators. Experimental murine studies investigating the effects of ionising radiation in radiotherapy- or spaceflight-simulating settings were considered eligible if they reported at least one bone morphological and one mechanical outcome. After screening and eligibility assessment, 11 studies were included and evaluated for methodological quality based on the robustness of the reported morphological and mechanical analyses.
Results: The included studies indicate that radiation exposure in murine bone is associated with dose-, time-, and radiation quality-dependent deterioration, with early, transient effects after single doses and more persistent damage following repeated exposures. Trabecular bone emerged as the most vulnerable compartment, showing reduced trabecular number and increased separation across several studies. Mechanical outcomes appeared to be site-specific: cortical-rich bones often retain strength despite trabecular loss, whereas trabecular-rich sites appeared more susceptible, suggesting microstructural deterioration may contribute to functional impairment even when whole-bone strength is relatively preserved.
Conclusions: These findings highlight that trabecular bone is the primary target of radiation-induced damage, with site-specific effects and persistent mechanical deficits, emphasizing the importance of multiscale assessment to understand and mitigate skeletal fragility in clinical and spaceflight contexts. However, a limited number of eligible studies and heterogeneity of experimental designs could reduce the strength of direct comparisons and the generalizability of these conclusions.
This study investigates the quasi-static equalbiaxial compression behavior of 3D-printed Miura-ori metamaterials incorporating both out-of-plane and in-plane gradient configurations. The Miura-ori structure, composed of tessellated parallelogram units, exhibits pronounced anisotropic behavior due to its unique folding geometry. To assess this behavior, specimens were fabricated using ABS resin and subjected to equalbiaxial compression in three orthogonal directions: the xy-direction (in-plane compression), the yz-direction (edge-on side loading), and the xz-direction (accordion-like profile loading). In the out-of-plane gradient design, the acute angle ϕ was varied across layers, significantly influencing both yield stress and specific energy absorption (SEA). Compared with the uniform design, gradient configurations exhibited reduced mechanical performance in the xy-direction and yz-direction, and enhanced properties in the xz-direction. In addition, in-plane (x-direction) gradient structures were evaluated under xy-, yz- and xz- direction compression. The results indicate that gradient configuration specimens exhibit significantly lower yield stress and specific energy absorption than uniform structure specimens, with deformation initiating preferentially in regions with smaller acute angles and lower local stiffness. The results highlight the strong influence of geometric gradation and loading direction on the mechanical performance of Miura-ori metamaterials. This work provides new insights into the design and optimization of origami-inspired energy-absorbing structures for use in advanced mechanical, aerospace, and protective engineering applications.
Rationally coupling nanoscale material design with macroscopic architecture is crucial for achieving lightweight absorbers with broadband and strong electromagnetic (EM) wave attenuation. Herein, multiscale-engineered polyimide (PI)/MXene/Ni aerogels integrating magnetic Ni nanochains, dielectric MXene sheets, and anisotropic porous architectures are reported. Ni nanochains with controlled morphology were synthesized via NaOH-assisted hydrazine reduction, while directional freezing enabled the fabrication of random, parallel, and normal aerogel architectures. The normal-aligned PI/MXene/Ni aerogel exhibits a remarkable minimum reflection loss (RLmin) of -72.42 dB at 2.8 mm. Guided by a genetic-algorithm optimization, tri-layer assemblies further expand the effective absorption bandwidth (EAB) to 8.4 GHz while maintaining an outstanding RLmin of -61.69 dB. The superior absorption originates from synergistic dielectric-magnetic-structural losses, including interfacial polarization, ohmic/eddy-current dissipation, and gradient impedance matching enabled by the layered porous framework. Beyond EM attenuation, the aerogels feature ultralow density, high compressive strength, enhanced hydrophobicity, intrinsic flame retardancy, and low thermal conductivity, providing effective infrared stealth and thermal protection. This work demonstrates a multiscale design strategy to create multifunctional, broadband EM absorbers for demanding electronic and aerospace environments.
Stress and strain sensors are core measurement technologies used across a wide range of fields, including healthcare, environmental monitoring, aerospace and intelligent manufacturing. Although both capture aspects of mechanical behaviour, they are governed by distinct physical quantities: stress sensors measure internal mechanical stress, whereas strain sensors detect geometric deformation. Here, within the broader landscape of mechanical sensing, we discuss the differences between stress and strain sensors to clarify the common misconceptions that can obscure their distinctions, lead to misinterpretation in performance evaluation and affect sensor design. This Review establishes a unifying, mechanics-oriented framework that aligns sensing mechanisms, material systems and structural designs with stress-driven and strain-driven sensing pathways. It facilitates the mechanism-specific interpretation of performance metrics and integrates system-level considerations with artificial intelligence-assisted signal processing. The framework enables rational device design, reliable signal analysis and application-specific sensor selection, with relevance that extends beyond mechanical sensing.
This study proposes a prediction method for ceramic matrix composite thin plates (CMCTPs) with protective coatings under high-temperature conditions, based on the first-order shear deformation theory and the energy principle while considering thermal effects. It can successfully predict the variations in natural frequencies and resonant responses of CMCTPs over the experimentally validated temperature range of 25 °C to 800 °C, using a thermo-vibrational platform with a maximum temperature capability of 1500 °C. In addition, a thorough investigation of multiple key parameter influences on the dynamic characteristics of CMCTPs with and without coating is performed, with special focus on the effect of the coating on enhancing the thermo-vibrational resistance of such structures. The analytical results demonstrate that the protective coating significantly enhances the thermo-vibrational resistance of the structure. Optimization of the coating-to-substrate thickness ratio, elastic modulus ratio, and thermal expansion coefficient ratio is recommended to maximize vibration suppression performance, providing critical guidance for the dynamic design of coated CMCTP components in aerospace.
Polybenzoxazines (PBz) represent a versatile class of high-performance thermosetting polymers that have attracted significant attention for advanced composite applications due to their unique combination of properties including high glass transition temperatures, low polymerization shrinkage, excellent thermal stability, and molecular design flexibility. This comprehensive review examines the structure-property relationships governing PBz composite performance, from molecular design principles through network formation, composite reinforcement strategies, and ultimate application performance. The review systematically addresses benzoxazine monomer structure and its influence on polymer network architecture, explores the polymerization mechanism, and critically evaluates composite design strategies incorporating carbon-based nanofillers, fiber reinforcements, and hybrid filler systems. Detailed analysis of structure-property relationships reveals how molecular and composite architecture control thermal stability (glass transition temperatures exceeding 350 °C and char yields up to 92%), mechanical performance, electrical properties (dielectric constants as low as 2.67), and chemical durability. Processing techniques ranging from conventional compression molding to emerging additive manufacturing approaches are discussed in the context of morphological control and property optimization. Applications spanning aerospace structures, high-frequency electronics and protective coatings demonstrate the technological relevance of PBz composites. Critical challenges including network brittleness, high cure temperatures, and recyclability limitations are addressed alongside recent advances in dynamic covalent networks, vitrimer chemistry, and self-healing systems that promise to overcome these barriers. This review provides a comprehensive framework for understanding and engineering polybenzoxazine composites for next-generation advanced applications.
Early prediction of gestational diabetes mellitus (GDM) is crucial. This study evaluated the combined predictive value of sex hormone-binding globulin (SHBG) and visceral adipose tissue-derived serine protease inhibitor (vaspin) in early pregnancy for GDM. A retrospective case-control study was conducted involving 50 pregnant women diagnosed with GDM (GDM group) and 50 with normal glucose tolerance (control group) from January to December 2022 at Beijing Aerospace General Hospital. Fasting venous blood was collected at 8-13+6 weeks of gestation. Serum levels of SHBG and vaspin were measured by enzyme-linked immunosorbent assay (ELISA). Clinical data including age, body mass index (BMI), parity, family history of diabetes, gestational age, amniotic fluid index (AFI), mode of delivery, and neonatal birth weight were compared between groups. Logistic regression and receiver operating characteristic (ROC) curve analyses were performed to evaluate the predictive value of individual and combined biomarkers. Pre-pregnancy BMI, cesarean section rate, and neonatal birth weight were significantly higher in the GDM group. Serum SHBG levels were significantly lower (392.26 ± 46.34 vs. 454.49 ± 31.66 nmol/mL, p<0.001), and vaspin levels were significantly higher (3.04 ± 0.47 vs. 2.54 ± 0.36 ng/mL, p<0.001) in GDM. The combined model of SHBG and vaspin showed superior predictive performance (AUC=0.934, accuracy=91.0 %, sensitivity=87.2 %, specificity=94.9 %) compared to either biomarker alone. The combined measurement of serum SHBG and vaspin in early pregnancy suggests a potentially useful predictive performance for GDM. While limited by the relatively small sample size and the research-use-only nature of the vaspin assay, this dual-biomarker approach warrants further validation in larger studies before its clinical applicability can be fully established.
Hard and brittle material components with complex curved surfaces are widely used in critical foundational parts within aerospace, optoelectronics, and other fields. Their machining quality directly determines the performance and reliability of high-end equipment. However, the inherent properties of hard and brittle materials make them prone to surface/subsurface damage during traditional polishing processes, and maintaining the form accuracy of complex curved surfaces is challenging. Although abrasive waterjet polishing enables non-contact flexible processing, its energy efficiency is low. Additionally, although ultrasonic-assisted polishing can improve material removal, its spatial localization is insufficient, limiting energy utilization efficiency. To address these issues, this paper proposes a novel method of focused, ultrasonic, vibration-assisted abrasive waterjet polishing. The influence of the radiation force and cavitation force of the focused ultrasonic field on abrasive particle motion is analyzed, and analytical equations for abrasive particle velocity are established. Subsequently, single-factor and response surface methodologies are employed to systematically evaluate the influence of process parameters on machining quality and efficiency. The material removal process during FUAP involves both plastic shearing/chip formation and localized brittle fracture. Focused ultrasonic assistance promotes micro-cutting and plastic shearing, while localized crushing pits indicate that brittle fracture remains non-negligible. The focused ultrasound superimposes alternating stress onto the impact action, mitigating microscale crushing pit defects during the brittle removal process of monocrystalline silicon. Furthermore, appropriately increasing ultrasonic power, enlarging abrasive particle size, and raising abrasive concentration all contribute to enhanced material removal from monocrystalline silicon. Adjusting the nozzle height to the effective region of the focused ultrasonic energy field promotes material removal via chip formation while avoiding pit defects caused by excessive fracture. These results suggest that focused ultrasonic energy can be effectively integrated into abrasive waterjet polishing to enhance material removal while suppressing brittle surface defects, thereby offering a promising strategy for the ultra-precision finishing of hard and brittle components with complex curved surfaces.
Integration of composites into the fabrication process of structural assemblies within the aerospace, automotive, marine or civil engineering industries represents a rational solution adopted by leading companies which are guided by the necessity for novel low-weight, high-strength, and high-stiffness materials. During the manufacturing process and throughout the service life, fiber-reinforced polymer structures are subjected to impact loading, either accidentally or as an inherent requirement of the operational cycle. Firstly, general aspects regarding impact loading and some parameters used for its characterization are briefly described. Recent progress regarding the influence of the stacking sequence, fiber type, and impactor geometry on the impact performance of Kevlar and glass fiber reinforced composite materials is emphasized. Additionally, the effects of environmental factors (such as temperature, UV radiation, or humidity) on the impact energy absorbed by polymers reinforced with each of the two types of synthetic fibers are presented. Finally, the importance of directing the researcher's judgment towards improving the characteristics of materials subjected to impact, from a sustainable perspective, is motivated through the presentation of the impact behavior of polymer composites reinforced with Kevlar fibers or glass fibers hybridized with vegetable fibers.
Ceramic fiber insulation tile (CFIT) is a brittle porous ceramic fiber material. Its three-dimensional random network structure yields low density, high porosity, low thermal conductivity, and excellent high-temperature stability, making it a widely used material in aerospace thermal protection systems. This renders it particularly crucial to explore fracture dimensions, improve the fracture toughness of materials, and circumvent internal defects. In this study, the numerical simulation and experimental approaches are employed to investigate the fracture behavior and toughening mechanism of CFIT. First, a three-dimensional network model and macroscopic finite element (FE) model of CFIT are established, and the validity of the macroscopic FE model is confirmed by comparison with fracture experimental results. Meanwhile, the effects of CFIT porosity, fiber length, fiber diameter, and fiber orientation angle on fracture toughness are systematically investigated. Furthermore, based on practical requirements, the dimensions and structure of the ceramic fibers are determined, thereby elucidating the mechanism through which changes in crack size influence fracture behavior. Finally, fracture behavior under the macroscopic model is analyzed by introducing different crack sizes and prefabricated defects, and the influence laws of crack size and prefabricated defects on CFIT are determined. In summary, this study provides theoretical guidance for research on the fracture behavior of porous ceramic fiber materials.
Extraterrestrial environments have an impact on cardiac output, vascular integrity, and endothelial function. This Update Review aims to integrate multi-domain cardiovascular preventive strategies through advanced biomedical and lifestyle interventions in long-duration spaceflight, as well as assessing the adoption of such innovations using Rogers's Diffusion of Innovations (DOI) theory among spaceflight stakeholders. To conduct this Update Review, we restricted the inclusion criteria to conceptual and interdisciplinary literature in English related to spaceflight in the PubMed, Scopus, and Google Scholar datasets. Articles aligned with the study scope and the relevant keywords about spaceflight, cardiovascular health, and DOI were included. Thematic synthesis was used to integrate the results with the DOI theory and advanced prevention approach on cardiovascular health, with potential benefits in space medicine. Our assessment of current literature suggests that a combined, multi-domain framework for cardiovascular protection in extraterrestrial environments, incorporating lifestyle strategies with complementary biomedical approaches, would be most useful in the pre-Moon or Mars phase. This review underscores how strategic adoption of protective innovations, coupled with a communication model like DOI, can target late adopters and accelerate effective prevention strategies across the aerospace healthcare ecosystem.
This technical study presents calendering as an innovative and continuous industrial solution for the reuse of uncured carbon fiber prepreg scraps, which are typically discarded in large quantities in the aerospace sector. By applying heat and pressure through rollers, the authors successfully transform residual fragments into functional sheets, promoting a circular economy that reduces environmental impact and raw material costs. Although the process induces a slight fiber misalignment, which decreases longitudinal strength, the results reveal significant improvements in transverse properties and increased material isotropy. Finally, the research validates the feasibility of this technique by fabricating a curved structural demonstrator, proving that these recycled composites maintain high stiffness and suitable thermal stability for secondary aeronautical applications.
The rapid expansion of space exploration has increased the demand for lightweight structural materials capable of maintaining performance under extreme thermal conditions. Carbon fibre-reinforced polymers (CFRPs) offer high specific strength and low density; however, their application in cryogenic environments remains challenging due to the brittleness of epoxy matrices, which are susceptible to cracking at low temperatures and under thermal cycling. In this work, two strategies were investigated to improve the damage tolerance of epoxy nanocomposites: (i) the use of a biscitraconimide-based (BCI) resin and (ii) the incorporation of methyl methacrylate-butadiene-styrene (MBS) core-shell particles. Low additive contents were evaluated to identify formulations compatible with prepreg manufacturing. The incorporation of 2 wt.% of MBS core-shell particles significantly improved the impact resistance of the nanocomposites and was selected for CFRP laminate production. When applied to CFRPs, the modified matrix maintained the overall tensile behaviour while increasing the interlaminar fracture toughness by 102% and 122% at room (RT) and cryogenic temperatures (CT), respectively. These findings demonstrate that matrix modification using low-content toughening is an effective strategy to enhance the cryogenic performance of CFRPs, contributing to the development of lighter and more resilient composite structures for next-generation space systems.
Concrete shrinkage is significantly influenced by the restraint level, and cracking often occurs under specific restraint conditions, thereby adversely affecting structural performance. Investigating the effect of restraint on shrinkage cracking is of great significance for enhancing early-age durability and ensuring structural safety. In this study, four distinct restraint levels (0%, 35%, 55%, and 75%) were established by varying the thickness of the inner steel ring. The influence of varying degrees of restraint on the shrinkage behavior was investigated, with digital image correlation (DIC) and internal strain gauge measurement employed to observe the strain and predict the risk of cracking. As the degree of restraint increases, the inner steel ring inhibits the free radial shrinkage of concrete more significantly, thereby inducing greater tensile strains at both the outer circumferential surface and the interior. The surface strain accumulation far exceeds the interior response due to the drying gradient. During the first 60 h, the shrinkage strain measured by both methods exhibited the most rapid evolution, indicating a critical high-risk period for cracking. These results advance the understanding of restraint effects in concrete and comprehensively clarify the relationship between the degree of restraint and the shrinkage, which accurately captures the evolution of shrinkage, facilitates the transition from empirical to quantitative design for crack-resistant materials and supports their customized optimization under practical engineering loading conditions.
[This retracts the article DOI: 10.1016/j.heliyon.2023.e22341.].
The utilization of hydrazine (N2H4) as a liquid-phase carrier offers a promising approach for on-demand H2 production. However, its splitting is challenged by parasitic cleavage of the N-N bond, which generates ammonia byproducts and wastes energy. Here, we designed a single-atomic catalyst comprising Ru(IV) coordinated by four oxygen atoms on a Ti felt, achieving near-quantitative selectivity (99.9%) for N2 and H2 at an ultralow cell voltage of 35 mV with a current density of 100 mA cm-2, significantly outperforming conventional Ru-based catalysts with N2 selectivity below 66%. Mechanistic investigations reveal that O-coordination stabilizes the high-valent Ru(IV) in a low-spin d4 electronic state. This electronic state promotes a monodentate end-on adsorption configuration of N2H4, enhancing electron donation from the terminal adsorbed N2H4 while minimizing the Ru→N back-donation into the N-N σ* orbital. Consequently, N-N cleavage is effectively suppressed, promoting successive N-H bond cleavage for clean H2 release. Impressively, this catalyst enabled direct conversion of aerospace wastewater containing 1,780 ppm of N2H4 to pure H2 (99.99%) with a net-negative carbon footprint of -2.25 kg CO2/t, offering an innovative and sustainable approach for waste-to-energy in the environmental and energy fields.
Restoring images captured in low-light rainy scenes is challenging because brightness degradation and rain corruption are strongly coupled. Enhancing visibility may amplify hidden rain streaks and noise, whereas aggressive deraining can suppress already weak scene structures. Existing cascaded pipelines and general restoration models often struggle to handle this interaction effectively. In this paper, we present the Degradation-Robust Hue Prior Network (DHP-Net), a single-stage framework for low-light rainy image restoration that combines degradation-robust hue prior guidance with perturbation-aware feature modulation. Specifically, DHP-Net extracts multi-scale hue priors to provide stable structural and color cues under coupled degradations, and it injects them into a hierarchical Transformer restoration backbone. To further improve interaction among entangled feature responses, we introduce a Channel-adaptive Attention Perturbation Module that reorganizes intermediate representations before cross-channel aggregation. In this way, the proposed model jointly promotes visibility enhancement, rain removal, and structure preservation within a unified architecture. Extensive experiments on the Low-Light Rain (LLR) benchmark show that DHP-Net achieves 33.14 dB Peak Signal-to-Noise Ratio (PSNR) and 0.9252 Structural Similarity Index Measure (SSIM) on synthetic data and also delivers superior perceptual quality on real-world low-light rainy images, consistently outperforming existing state-of-the-art restoration models.
The glymphatic-meningeal pathway, important for brain homeostasis, depends on the drainage function of the cervical lymphatic system. Although new therapies aim to modulate this pathway, a lack of methods for quantifying lymphatic drainage function hinders our ability to understand how targeting the cervical lymph nodes may benefit brain health. To address this, we developed and applied a fluid transport model to dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) data to visualize and quantify tracer-tagged lymph through the deep cervical lymph nodes (dcLN). The model incorporated physical principles of solute transport to provide a biologically interpretable framework for analyzing microflows in real-time. We applied this model to investigate the effects of chronic hypertension on dcLN drainage by comparing normotensive Wistar-Kyoto rats with spontaneously hypertensive stroke-prone (SHRSP) rats. In normal rats, the model revealed complex and tortuous lymph streams, of a 200 kDa tracer transported through the sinus system of the dcLN. In contrast, SHRSP rats exhibited significantly altered fluid dynamics, characterized by simpler stream patterns and reduced flow through the dcLN. These findings demonstrated that untreated chronic hypertension adversely affects lymph node drainage function. This provides new insight into impaired lymphatic drainage as a mechanism linking systemic disease to brain health.
To improve the speed and accuracy of airborne inertial navigation systems during ground initial alignment, this paper proposes a rapid self-alignment method suitable for fixed-wing aircraft during the taxi-to-takeoff phase on the runway. This approach leverages pre-surveyed runway heading data to transform the velocity vector calculated in the navigation frame to the runway frame. By utilizing the geometric constraint that the aircraft's actual position during ground taxiing must remain within the runway boundaries and closely follow the runway centerline, the proposed method employs a dedicated Kalman filter to achieve rapid initial alignment. Both simulations and flight tests demonstrate that the proposed method can achieve rapid initial alignment within 30 s during the runway taxiing phase, with attitude, velocity, and position accuracy levels comparable to those of GNSS-aided in-motion alignment. This method eliminates the need for external aiding equipment and can serve as an emergency initial alignment solution for airborne inertial navigation systems under GNSS outage conditions, effectively enhancing the aircraft's autonomy and rapid response capability.
In deep-space exploration and remote sensing, characterizing radiative transfer in complex planetary atmospheres is fundamental for robust target detection and optical navigation. On the Martian surface, intense scattering and attenuation by dust aerosols pose severe environmental interference, challenging star sensors used for high-precision navigation. To address this, this study develops a spectral radiative transfer model based on the Null Collision Monte Carlo Method to characterize the optical background of the dusty Martian atmosphere. Mie scattering theory is employed for dust particles, while gas molecular absorption is modeled via line-by-line integration. The simulated sky radiance is validated against Mars rover Navcam observations, yielding an average relative error of 7.83% between the modeled and observed radiance values across scattering angles greater than 5°. Building on this, an imaging link model evaluates surface-based detection performance, including signal-to-noise ratio, detection success probability, and star count. Optical parameters-aperture, field of view, and integration time-are optimized for nighttime and dawn-dusk modes. Spatio-temporal assessments are conducted globally across Martian years, focusing on the Zhurong landing site and Tianwen-3 candidates. Finally, an Earth-environment equivalence experiment using a 60% transmittance filter verifies the design's robustness. This work confirms the feasibility of star-sensor-based attitude determination on Mars.