Search Results (181)

High-altitude hypoxia is associated with sleep disruption, affective fluctuation, and changes in cognitive performance, yet prior findings remain markedly heterogeneous in both direction and magnitude. To clarify this variability, this structured narrative review synthesizes evidence from systematic reviews, meta-analyses, and key empirical studies on psychological and cognitive adaptation to high-altitude hypoxia, with a particular focus on personality and related traits. The review is organized along three axes: exposure context and characterization (real-altitude field/residential exposure, hypobaric chambers, normobaric hypoxia, expedition settings, and dose alignment), exposure duration and time course, and outcome domains spanning sleep/fatigue, affective adaptation, and cognitive performance. Across the literature, cognitive effects appear domain-specific and strongly conditioned by exposure dose, temporal stage, and task characteristics, whereas sleep disturbance during the early acclimatization period emerges as one of the more consistent findings and appears closely intertwined with anxiety-related responses. Although direct personality-related evidence remains limited and uneven, the available findings can be organized into a testable trait–process–outcome framework that distinguishes candidate associations with relatively more direct evidence from mechanism-informed hypotheses. Neuroticism/emotional stability and anxiety-related traits have received comparatively more direct empirical investigation than other personality domains, but the available evidence is insufficient to regard them as established predictors of high-altitude adaptation. The roles of conscientiousness, resilience/hardiness, extraversion, agreeableness, and openness remain more tentative and are better treated as targets for prospective testing. We therefore propose that personality-related dispositions may influence adaptation-relevant outcomes through candidate processes involving threat appraisal, coping, resource regulation, and social interaction. We conclude that future research should strengthen exposure dose characterization, specify the boundary conditions for generalizing across real-altitude, hypobaric-chamber, normobaric hypoxia, and expedition settings, and adopt longitudinal, multilevel, and ecologically valid designs to test personality-related pathways more rigorously. Full article

Advances in healthcare have led to substantial growth in the global population of cancer survivors, yet young adult cancer survivors (YACS) aged 18–39 years remain an underrepresented population in cancer survivorship research. This review examines the health challenges and psychosocial factors that shape nutritional status in YACS, with the aim of informing age-appropriate nutritional care. YACS face significant financial and psychosocial demands unique to this life stage, balancing education, early careers and family responsibilities. They report greater unmet nutritional and health needs than other age cohorts, in addition to concerns regarding long-term side effects, financial strain, fear of cancer recurrence and increased responsibility for managing their own care. Cancer treatment can cause nutrition impact symptoms (e.g., nausea, taste changes, fatigue, dysphagia and gastrointestinal (GI) disturbances) that may persist for years, and YACS are vulnerable to late effects such as endocrine dysfunction, cardiometabolic disease, chronic pain and osteoporosis, all of which can be influenced by diet. Poor dietary patterns have been observed in YACS, indicating low intakes of fruits, vegetables, fibre and dairy, and higher consumption of saturated fat, sodium and processed foods. This narrative review evaluated fourteen nutritional intervention studies targeting YACS aged 18–39. Most existing interventions demonstrate minimal recruitment and retention rates, small sample sizes, and a reliance on self-report methods rather than objective nutritional measures. These limitations highlight the need for a deeper understanding of YACS’ specific nutritional needs and more effective strategies to engage this cohort. Future research should prioritise larger, more representative samples, incorporate objective nutritional and clinical measures, and explicitly address psychosocial and age-related barriers to healthy eating in young adulthood. Full article

Cyclic high-pressure gas impact is a promising waterless stimulation method for enhancing permeability in deep low-permeability coal seams. However, the nonlinear fracture evolution, cumulative fatigue damage, and coupled fracturing mechanisms during repeated gas impacts remain insufficiently understood. In this study, cyclic high-pressure gas impact tests were conducted on unconfined synthetic rock-like specimens under gas pressures of 5 MPa and 7.5 MPa. The macroscopic crack networks induced by repeated impacts were quantitatively characterized using digital image processing and box-counting fractal analysis. Ultrasonic P-wave velocity measurements were used to reconstruct the spatial evolution of internal damage after each impact, and an empirical Weibull statistical damage model was established to describe the nonlinear fatigue degradation process. In addition, two-dimensional LS-DYNA numerical simulations were performed to reveal the transient stress wave propagation and stress-field evolution during cyclic impacts. The results show that fracture propagation under cyclic gas impacts exhibits a distinct nonlinear pattern, characterized by slow early-stage damage incubation followed by rapid late-stage crack coalescence. The fractal dimension of the surface crack network increased markedly after repeated impacts, reaching a maximum of 1.51 under the 7.5 MPa condition. Ultrasonic damage analysis further indicates that, based on path-averaged evaluations, apparent damage is more pronounced near boundaries at the lower pressure, whereas higher pressure induces severe structural degradation along the central measurement paths, with a maximum damage value of 0.47. The combined experimental and numerical results suggest that the initial impacts generate transient stress waves and cumulative microcracking, thereby progressively weakening the rock matrix. This progressive degradation subsequently enables quasi-static gas wedging to drive macroscopic crack propagation and coalescence. These findings provide a preliminary phenomenological baseline for understanding cyclic gas-induced cracking, providing a preliminary basis for understanding waterless reservoir stimulation by cyclic gas impacts. Full article

When a wearable gait predictor is personalized to a new user, a short calibration session may contain missing channels, sensor-placement changes, electrode shift, noise, fatigue, or other non-ideal effects. Treating all calibration samples as equally trustworthy can overpersonalize the prediction head and induce harmful drift away from the source model. We study calibration quality as a control signal for new-user personalization and propose Dynamic Trust-Region Head Adaptation (DTR-HA), a head-only adaptation rule that combines reliability-weighted calibration loss with a reliability-scaled source-head anchor. The temporal encoder is frozen, and lower reliability strengthens a soft source-head penalty. The Bilateral Lower-Limb Neuromechanical Signals dataset (BLISS) defines the target early gait-phase prediction task with 21-subject leave-one-subject-out evaluation; complete-bout calibration/test separation; and 0, 100, and 200 ms horizons. K2MUSE supplies real non-ideal calibration conditions for mechanism-level stress testing. In K2MUSE 75% bad-calibration tests with a held-out blind context-based reliability scorer, DTR-HA reduced empirical risk by 20–23% relative to plain head adaptation, improved macro-F1 by 0.018–0.022, and achieved 25/28 paired subject–condition wins with fewer negative-adaptation cases. In a secondary BLISS calibration-pollution check, DTR-HA kept macro-F1 within 0.003 of plain head adaptation while reducing calibration-induced head drift across all horizons. These results support calibration quality as an adaptation-stage control signal for stable, lightweight wearable gait personalization under unreliable calibration. Full article

The present study is situated within the broader research context of optimizing the use of C60 steel in industrial applications, with a particular emphasis on enhancing durability and fatigue resistance, two critical factors in the field. C60 steel is renowned for its exceptional combination of strength and hardness. However, a critical evaluation is necessary to ascertain the impact of thermal and thermochemical treatments on its performance under fatigue conditions. An investigation was conducted into the crack formation process and the early stages of fatigue in C60 steel. The effects of heat treatment (hardening and tempering) were compared with those of thermochemical treatments (oxidation) on the steel’s microstructure. Furthermore, the performance of C60 steel under fatigue conditions was evaluated based on the applied treatments. The insights gained from this research can optimize the use of this steel in industries requiring high resistance and durability. The study’s methodology encompassed the execution of fatigue tests on a four-point bending machine, a procedure that was meticulously employed to ascertain the onset of microcracking. The C60 steel samples were processed in accordance with SR ISO 1099:2017, entitled “Fatigue testing. Axial load method”. To ensure consistency and comparability of results, the samples were fabricated from the same material charge and machined under identical conditions. A total of 26 samples were utilized, with 13 samples allocated to each treatment type: heat treatment by hardening, tempering, and thermochemical treatment by oxidation. To ensure comparability and scientific interpretability of the results, an identical applied force level was utilized for both treatment conditions. The frequency changes were monitored to evaluate the behavior of the materials under repeated stresses. Finally, the frequency changes were correlated with the number of cycles to identify when microcracks appeared and their evolution. The primary findings of this study indicate substantial disparities between the longevity of thermally and thermochemically modified specimens and the onset of microcrack formation in the material. Full article

This study investigates hydrogen-assisted fatigue crack growth (FCG) in vintage pipeline steels to quantify grade-dependent degradation under hydrogen–natural gas blending conditions. Fatigue behavior was evaluated using compact-tension specimens extracted from API X52 and X70 pipeline steels and tested in natural gas–hydrogen mixtures at a total pressure of 6.9 MPa and ambient temperature. Hydrogen concentration was systematically varied from 0% to 100% H₂ to assess its influence on crack-length evolution, fatigue crack growth rate, and fracture morphology. Crack propagation was characterized as a function of the stress-intensity-factor range, and scanning electron microscopy was used to examine hydrogen-induced changes in fracture mechanisms. The results demonstrate that FCG accelerates as hydrogen concentration increases, with a strong dependence on steel grade. X70 exhibited substantially greater hydrogen-induced FCG acceleration than X52, despite showing better fatigue resistance under hydrogen-free conditions. Fatigue life reductions approached 60% for X70 at 100% hydrogen, compared with approximately 30% for X52 under the same conditions. Significant early-life sensitivity was observed in X70 even at low hydrogen concentrations, whereas X52 showed more pronounced acceleration during later stages of crack growth. The influence of hydrogen was nonlinear and tended to stabilize at elevated blend fractions, indicating a saturation-type response once hydrogen-assisted crack growth became dominant. Fractographic analyses revealed a transition from ductile tearing in natural gas environments to terrace- and facet-controlled crack propagation in hydrogen-rich environments, accompanied by secondary cracking and river-pattern features. These findings demonstrate that hydrogen–natural gas blending can significantly alter fatigue crack growth behavior and relative material performance in pipeline steels, highlighting the need for grade-specific integrity assessment of existing pipeline infrastructure. Full article

High-RAP asphalt mixtures are highly susceptible to fatigue brittle fracture. This study investigated the fatigue damage evolution of basalt fiber (BF)-reinforced high-RAP mixtures. Four-point bending fatigue tests were performed to evaluate the stiffness damage factor and the ratio of cumulative dissipated energy change $R_{CEDC}$. The ExpDec2 model and a second-derivative criterion were utilized to quantify steady-state energy dissipation and partition damage stages. Results indicate that BF extended fatigue life, yielding a 55% improvement at 70% RAP content. Model evaluations revealed that in the initial stage, increasing RAP delayed the critical damage inflection point due to accelerated non-steady damage, whereas BF shifted inflection points forward by constraining early damage accumulation. In the stable propagation stage, BF reduced the energy dissipation rates of 50% and 70% RAP mixtures by 44% and 22%, respectively. These quantitative results provide essential performance data regarding the effect of BF on the fatigue life and energy dissipation of high-RAP mixtures, serving as a practical reference for the design and durability optimization of sustainable asphalt pavements. Full article

As a core load-bearing component for railway vehicles, rails are largely responsible for the safety and stability of train operation, and their service performance is inherently governed by material microstructure. In this study, rails with varied pearlite interlamellar spacing were prepared and laid on field tracks for 8 months of service testing to investigate the influence of pearlite interlamellar spacing on rail wear and rolling contact fatigue (RCF). The results indicate that decreasing pearlite interlamellar spacing facilitated tread work hardening and reduced cumulative wear loss of rails. At the early service stage, rails with coarse pearlite lamellae exhibited earlier RCF crack initiation and longer crack morphologies, while rails featuring finer pearlite lamellae exhibited the latest-occurring crack initiation. With prolonged service duration, wear loss rose continuously, and the tread hardening rate first increased sharply and then tended to gradually become stable. Obvious differences in damage evolution were observed for rails with different pearlite interlamellar spacing. Coarse-lamellar rail suffered sparse short cracks dominated by wear; fine-lamellar rail developed dense fast-growing cracks controlled by RCF; and medium-lamellar rail achieved a relatively good balance between wear and RCF. A competitive relationship exists between wear and RCF during rail service. Reasonable regulation of pearlite interlamellar spacing facilitates a balanced evolution of wear and RCF, which provides a feasible microstructural optimization strategy for improving the service performance and service life of pearlitic rails. Full article

The development of electric bus superstructures requires an integrated engineering approach combining structural design, numerical simulation, experimental validation and durability assessment. This need is particularly important for electric buses, where heavy roof-mounted battery systems and auxiliary components influence structural load paths, fatigue durability and rollover crashworthiness. This paper presents a measurement-supported workflow for the development of a virtual electric bus superstructure model, including finite element analysis, multibody dynamics simulations, operational load assessment, fatigue-oriented evaluation and rollover crashworthiness analysis. The finite element model is used to assess static load cases, modal properties and structural response under selected design conditions. A multibody vehicle model with nonlinear suspension characteristics is applied to simulate representative operating scenarios and to support the definition of dynamic load cases. Operational measurement data from previous work are used as a basis for realistic load characterization. Experimental torsional stiffness and modal tests are used to validate the numerical model. The main contribution of the study is the integration of these numerical, experimental and operational-data-based activities into a consistent early-stage verification process. The proposed workflow supports early identification of critical structural regions, assessment of design modifications and reduction in prototype-based design iterations. Full article

Advances in screening, surgical techniques, perioperative care, and multimodality treatment have progressively expanded the population of long-term survivors with early-stage non-small cell lung cancer (NSCLC). However, disease-free survival does not necessarily correspond to complete functional recovery after curative-intent treatment. Many patients continue to experience persistent fatigue, dyspnea, reduced physical activity, impaired exercise tolerance, muscle loss, and deterioration in health-related quality of life despite adequate oncologic control. This narrative review discusses functional recovery as a survivorship endpoint in early-stage NSCLC, focusing on recovery trajectories, physiologic vulnerability, frailty, sarcopenia, rehabilitation, symptom burden, and emerging biologic frameworks such as allostatic load. Increasing evidence suggests that survivorship after NSCLC should not be interpreted exclusively according to recurrence or survival metrics, but also according to the ability to recover physiologic reserve, autonomy, and daily functioning after treatment. Functional recovery appears heterogeneous and influenced by multiple interacting factors, including baseline reserve, systemic inflammation, physical inactivity, behavioral adaptation, and cumulative stress burden. Rehabilitation strategies, structured symptom surveillance, and patient-reported outcomes may help identify vulnerable patients and improve long-term survivorship trajectories. Future survivorship models should probably integrate oncologic outcomes with longitudinal functional assessment to better characterize recovery patterns after treatment. Full article

In hybrid rolling bearings operating under extreme high-temperature and high-load conditions, steel rolling elements are prone to early failure, which has accelerated the widespread adoption of ceramic materials. To address the limitations of conventional studies, which have focused mainly on macroscopic wear parameters while neglecting subsurface failure mechanisms and the relationship among sintering process, microstructure, and fatigue performance, this work systematically compares the tribological behavior of Si₃N₄ ceramic balls fabricated by high-pressure electric resistance hot-pressing (REHP) and B₄C ceramic balls prepared by conventional hot pressing (HP) against 52100 steel counterparts. The central innovation of this study lies in clarifying, based on Hertzian contact theory and Lundberg-Palmgren life theory, that subsurface orthogonal shear stress, rather than surface compressive stress, is the fundamental driving force for contact fatigue failure of ceramic balls. In addition, two distinct damage evolution modes are revealed: B₄C exhibits early-stage brittle fracture and large-scale spalling, whereas REHP-Si₃N₄ is characterized by microcrack initiation and slow crack propagation. Moreover, the intrinsic mechanism by which the REHP process significantly enhances the contact fatigue life of ceramics is elucidated; namely, it refines grain size, eliminates residual porosity, and increases densification. The results show that, under the same high-load conditions, the mass loss of REHP-Si₃N₄ ceramic balls is only 35.7% of that of HP-B₄C, while the service life is extended by 20%. This work provides a key theoretical basis for ceramic material selection and sintering process optimization in high-performance hybrid bearings. Full article

Adhesive joints are widely used in structural applications. However, they are susceptible to degradation under service loads and adverse environmental conditions, leading to eventual catastrophic failure. Thus, the advancement of monitoring tools that can deliver real-time data on the deterioration of adhesive joints is crucial for enhancing the reliability of structures. This study investigated the feasibility of using electrical impedance responses to monitor integrity degradation under tensile and fatigue loading in single-lap adhesive joints in aluminum alloy and carbon fiber-reinforced polymer (CFRP) specimens. Previous works on electrical impedance monitoring of adhesive joint integrity invariably employed conductive adhesives. Theoretical considerations based on the concept of a capacitive system indicate that electrical impedance monitoring may still be feasible even if the joint is non-conductive. This has important implications as it suggests that the structural health of many existing ordinary adhesive joints may be amenable to impedance-based monitoring. To test this possibility, neat epoxy adhesive joints without the addition of conductive constituents were fabricated with aluminum and composite adherends. The specimens were subjected to tensile and fatigue degradation while the impedance responses under different excitation frequencies were monitored. The results showed that impedance monitoring is insensitive for detecting damage during tensile failure because the onset of debonding that produces a detectable impedance change occurs too close to the unstable final failure. For fatigue cycling, debonding developed at an early stage and evolved in a stable manner, and the impedance gradually increased with the number of fatigue cycles, reflecting the development of fatigue damage. These findings indicate that impedance-based monitoring on non-conductive adhesive joints has strong potential for tracking structural integrity degradation, particularly for fatigue loading. Full article

Background: Fatigued driving is a key contributing factor to major traffic accidents. Existing detection technologies suffer from issues such as delayed identification, high error rates, and a lack of quantified causal relationships between physiological and behavioral indicators. This study aims to clarify the intrinsic relationship between electrophysiological and driving behavior data during the progression of driving fatigue. Methods: Four categories of driving behavior data and electrocardiographic (ECG) heart rate variability (HRV) indicators were selected as the study subjects. Based on a four-stage standardized simulated driving experiment ranging from wakefulness to severe fatigue, the correlations between indicators were quantified using Pearson correlation analysis, and a four-layer physiological–behavioral fusion fatigue assessment model was constructed. Results: Autonomic dysregulation is the intrinsic cause of abnormal driving behavior. The two exhibit a highly synchronized, stepwise progressive evolution pattern, with |r| ≥ 0.75 among core indicators. The accuracy of the constructed model exceeded 90% for all fatigue stages, reaching 97.8% for severe fatigue detection, with a response time of ≤0.5 s. Conclusions: This model effectively addresses the limitations of single-monitoring technologies and provides theoretical support and technical guidance for multimodal identification and graded early warning of driving fatigue. Full article

Background: Cancer-Related Fatigue (CRF) significantly impairs physical performance and quality of life (QoL) in patients with non-small-cell lung cancer (NSCLC). The OVER-CRF study evaluated the feasibility, safety, and preliminary efficacy of a personalized pulmonary rehabilitation (PR) program combining supervised exercise and education during active treatment. Methods: Patients with stage II–III NSCLC were randomized to Early-PR (initiated at the start of anticancer therapy) or Delayed-PR (initiated three months later). The 3-month intervention included two educational sessions and eight supervised exercise sessions. The primary outcome was adherence; secondary outcomes included safety, CRF (FACIT-FS), QoL (EORTC-QLQ-C30), and physical performance (6MWT). Results: Thirty-one patients were randomized (mean age 67.4 years). Adherence was excellent (Early: 86.7%; Delayed: 91.7%), exceeding feasibility thresholds. No exercise-related adverse events occurred. At 12 months, 50% of participants showed clinically meaningful CRF improvements. While both groups improved 6MWT performance during the intervention, the Delayed-PR group demonstrated more sustained QoL improvements from T1 through T3 compared to the Early-PR group. The dropout rate (25.8%) was consistent with the existing literature. Conclusions: Personalized PR is feasible and safe for NSCLC patients undergoing multimodal therapy. While early intervention provides immediate benefits, initiation timing may influence long-term QoL trajectories. These findings support integrating exercise and education into standard oncological care pathways. Full article

Acoustic emission (AE) technology was used to monitor the fatigue crack growth process of superalloy. The analysis results show that both the cumulative values and the K-entropy values of AE parameters have good correspondences with the three stages described by fracture mechanics, which makes it possible to characterize the process of fatigue crack growth. Since K-entropy is more sensitive to changes in fatigue state, the turning points between the second stage and the third stage are earlier than those defined by fracture mechanics, indicating that it has an early warning capability. The K-entropy of AE parameter was first proposed to represent the growth rate of fatigue crack. This method not only effectively decreased the large dispersion of change rate of AE parameters but also ensured the similarity with the fatigue crack growth rate, thereby optimizing the characterization of fatigue crack growth. Full article