Search Results (2,874)

During the service life of steel bridges, the structural stress histories display combined cyclic characteristics due to the superposition of low-frequency thermal loading and high-frequency vehicle loading. To investigate the fatigue performance under such loading patterns, a series of constant-amplitude and high-low frequency superimposed loading fatigue (HLSF) tests were conducted on notched specimens fabricated from Q355D bridge steel. The influence of HLSF waveform parameters on fatigue life was systematically investigated. Based on the fracture evolution mechanism, a concept of low-frequency periodic damage acceleration factor was proposed to effectively model the block nonlinear damage effects, and the applicability of existing fatigue life prediction models was discussed. The results show that the effect of average stress on the fatigue life under HLSF can be effectively considered by Walker’s formula. Low-amplitude ratios and low-frequency ratios indicate unfavorable loading conditions that may accelerate the Q355D fatigue damage accumulation, and these conditions are not adequately accounted for in current life prediction models. Compared to constant amplitude loading, HLSF can lead to a 66% and 46% reduction in high-frequency life when the amplitude ratio reaches 0.12 and the frequency ratio reaches 100. Compared to Miner’s rule, the proposed damage correction method reduces the life prediction error for HLSF by 11%. These findings provide valuable references for the fatigue assessment of bridge steel structures under the coupled effects of temperature and vehicle loading. Full article

Background: Ozone (O₃) pollution disrupts pulmonary circadian rhythms, yet the molecular mechanisms remain elusive. The Notch signaling pathway, critical for lung homeostasis, may crosstalk with the circadian clock system. Objective: This study elucidates the role of the Notch signaling pathway in O₃-induced lung circadian rhythm disruption. Methods: C57BL/6J mice were acutely exposed to O₃ (1.0 ppm, 3 h). Lung tissues were collected 24 h post exposure. Transcriptome sequencing coupled with GSEA identified dysregulated pathways; IHC and RT-qPCR validated core genes; GEO dataset (GSE58244) reanalysis assessed Notch3/4 knockout effects. Results: O₃ activated Notch signaling (NES = 1.85, FDR = 0.034) and disrupted the circadian pathway (NES = 1.84, FDR = 0.029), downregulating Bmal1 while upregulating Per2/3 and Notch3/4 (p < 0.05). Strong correlations (r > 0.8) existed between core genes of both pathways. Notch3/4 knockout exacerbated circadian disruption in a time-dependent manner upon O₃ exposure. Conclusion: O₃ induces lung circadian disruption via Notch3/4 activation, which provides novel mechanistic insights into pollutant-induced lung injury. Full article

The instantaneous AC-side output power of a two-stage single-phase inverter pulsates at twice the output voltage frequency, inducing second harmonic current (SHC) in the front-end DC–DC converter. While conventional SHC mitigation methods mainly focus on controller optimization for PWM-controlled DC–DC converters, LLC resonant converters, which have been widely adopted in two-stage single-phase inverters for high efficiency and soft-switching characteristics, lack tailored solutions due to frequency modulation complexities. To address this gap, this paper first analyzes the propagation mechanism of the SHC in terms of converter output impedance. Then, by simultaneously lowering the open-loop gain and increasing the output impedance of the DC–DC converter at 2f_N, this paper proposes a hybrid SHC mitigation strategy that achieves low SHC and fast dynamic performance for frequency-modulated LLC converters. Finally, a 28 V DC to 220 V/50 Hz AC inverter was developed, and the experimental results verified the effectiveness of the proposed control strategy. Full article

To evaluate the mechanical properties of connectors in timber–concrete composite (TCC) structures under low-cycle reversed loading, eighteen push-out specimens were designed and fabricated following the standard push-out test method. This study presents the first comparative analysis of the seismic performance between notch-bolted and ordinary bolted connections across three bolt diameters (12 mm, 16 mm, and 20 mm), addressing a gap in systematic experimental data for different connection types. Key performance indices under cyclic loading—including stiffness degradation, strength degradation, energy dissipation capacity, and ductility—were investigated. Furthermore, cumulative damage analysis elucidated the damage accumulation process, establishing a damage index (Dw) based on an energy method and proposing Dw = 0.6 as a critical early-warning threshold for failure. Practical recommendations for seismic design and engineering applications are provided. The results demonstrate that compared to ordinary bolted connections, notch-bolted connections achieve a 15–30% increase in ultimate bearing capacity and exhibit superior stiffness. Specimens with 16 mm bolts exhibited optimal ductility (ductility coefficient ξ = 3.6), while notch-bolted connections maintained stable ductility within the range of ξ = 2–3. Finally, a numerical model was developed using ANSYS finite element software. Validation against experimental results confirmed the model’s accuracy in simulating structural behavior. This research elucidates the cumulative damage mechanisms in TCC structures under cyclic loading, providing a theoretical basis for design optimization and valuable insights for promoting the seismic application of these composite systems. Full article

Background: T-cell acute lymphoblastic leukemia (T-ALL) is an aggressive malignancy of immature T cells, driven by dysregulated transcriptional networks and oncogenic signaling pathways. Here, we present the first comprehensive analysis of the expression and regulation of TSPAN32, a tetraspanin implicated in lymphocyte homeostasis, in T-ALL. Methods: Transcriptomic data from the Leukemia MILE study (GSE13159) were analyzed to assess TSPAN32 expression across leukemic subtypes. Gene Set Enrichment Analysis (GSEA) was performed to explore biological pathways associated with TSPAN32-correlated genes. For mechanistic validation, HPB-ALL cells were used as a model, with NOTCH signaling inhibited by γ-secretase inhibitor (GSI) treatment and TAL1–LMO1 overexpression induced through doxycycline-inducible lentiviral vectors. Gene expression changes were quantified by RT-qPCR. Results: TSPAN32 was frequently downregulated in T-ALL compared to healthy bone marrow, although expression was retained in a subset of cases. GSEA revealed that TSPAN32-correlated genes were inversely associated with cell cycle–related programs, consistent with its established role as a negative regulator of T cell proliferation. Mechanistically, TAL1–LMO1 overexpression strongly induced TSPAN32, while GSI-mediated NOTCH inhibition partially reactivated its expression. Interestingly, GSI treatment also increased TAL1 levels despite downregulating LMO1. Conversely, TAL1–LMO1 overexpression suppressed NOTCH1 and NOTCH3, highlighting a reciprocal regulatory interplay between NOTCH and TAL1/LMO1 oncogenic circuits that shapes TSPAN32 expression dynamics in T-ALL. Conclusions: This study identifies TSPAN32 as a novel transcriptional target under the influence of key leukemogenic pathways and suggests its potential role as a modulator of leukemic T cell proliferation, with implications for therapeutic strategies targeting TAL1 and NOTCH signaling. Full article

This study investigates the mechanical response characteristics and damage evolution behavior of TC4 alloy through quasi-static/dynamic coupled experimental methods. Quasi-static tensile tests at varying temperatures (293 K, 423 K, and 623 K) were conducted using a universal testing machine, while room-temperature dynamic tensile tests (strain rate 1000–3000 s⁻¹) were performed with a Split Hopkinson Tensile Bar (SHTB). Key findings include the following: (1) Significant temperature-softening effect was observed, with flow stress decreasing markedly as temperature increased; (2) Notch size effect influenced mechanical properties, showing 50% enhancement in post-fracture elongation when notch radius increased from 3 mm to 6 mm; and (3) Strain-hardening effect exhibited rate dependence under dynamic loading, with reduced hardening index within the tested strain rate range. The Johnson–Cook constitutive model and failure criterion were modified and parameterized based on experimental data. A 3D tensile simulation model developed in ABAQUS demonstrated strong agreement with experimental results, achieving a 0.97 correlation coefficient for load–displacement curves, thereby validating the modified models. Scanning electron microscopy (SEM) analysis of fracture surfaces revealed temperature- and strain rate-dependent microstructural characteristics, dominated by ductile fracture mechanisms involving microvoid nucleation, growth, and coalescence. This research provides theoretical foundations for analyzing Ti alloy structures under impact loading through established temperature–rate-coupled constitutive models. Full article

To investigate the impacts of dietary Bacillus-based probiotics and yeast-derived prebiotics on the hepatic transcriptome profile, 500 Hisex White laying hens were randomly allotted into five dietary treatments from 37 to 52 weeks of age: control; control + Bacillus subtilis; control + Bacillus subtilis and Bacillus licheniformis; control + Bacillus coagulans; and control + Saccharomyces cerevisiae yeast cell wall. Transcriptome analysis revealed a substantial number of differentially expressed genes exclusively between the control and prebiotic groups, identifying 2221 genes (FDR ≤ 0.05), with 980 genes upregulated (log₂ fold change 0.69 to 24.62) and 1241 downregulated (log₂ fold change −0.74 to −26.46). The top 10 upregulated KEGG pathways included protein export, glycerophospholipid metabolism, tryptophan metabolism, amino acid biosynthesis, alanine, aspartate, and glutamate metabolism, cofactor biosynthesis, propanoate metabolism, ABC transporters, 2-oxocarboxylic acid metabolism, and protein processing within the endoplasmic reticulum. In contrast, the most prominently downregulated pathways encompassed fructose and mannose metabolism, hedgehog signaling, PPAR signaling, Notch signaling, GnRH signaling, cell adhesion molecules, cytokine–cytokine receptor interactions, apelin signaling, glycosaminoglycan degradation, and RIG-I-like receptor signaling. These findings advance understanding of the hepatic transcriptomic response to yeast-derived prebiotics and identify key molecular pathways that could be targeted to enhance metabolic function in laying hens. Full article

Background: It is established that depression significantly contributes to tumor development, yet its molecular link to gastric cancer progression remains unclear. Methods: In this study, we examined depression-related gene expression profiles in relation to clinical prognosis and identified estradiol and the NOTCH3 gene as critical factors involved in gastric cancer progression in the context of depression. Using a chronic unpredictable stress-induced tumor-bearing mouse model, we validated the impact of depression on tumor development. Additionally, the underlying molecular mechanisms were explored through a range of biological techniques, including Western blotting, immunofluorescence, flow cytometry and immunohistochemistry. Results: Depression significantly accelerated gastric cancer growth in our mouse model, characterized by decreased estradiol levels and increased NOTCH3 expression. Importantly, exogenous estradiol supplementation effectively counteracted depression-induced tumor growth. Consistently, in vitro studies showed that estradiol treatment suppressed NOTCH3 expression in HGC-27 and YTN3 cell lines. Furthermore, NOTCH3 was shown to modulate intracellular reactive oxygen species levels by regulating SOD2 activity, thereby influencing cell proliferation. Conclusions: This work identified the estrogen/NOTCH3 signaling as a key link between depression and gastric cancer development, offering promising therapeutic strategies to improve outcomes for patients suffering from psychological disorders. Full article

This paper compares two types of interior permanent magnet synchronous motors (IPMSMs) to determine the most effective arrangement for electric vehicle (EV) applications. The comparison is based on torque ripple, power, efficiency, and mechanical objectives. The study introduces a novel technique that optimizes notching parameters in a selected motor topology by inserting a ship-shaped notch into the bridge area between double U-shaped layers. In addition, this study presents two comprehensive approaches of robust combinatorial optimization that are used in machines for the first time. In the first approach, modeling is performed to identify important variables using Pearson Correlation and the mathematical model of the Anisotropic Kriging model from the Surrogate model. Then, in the second approach, the proposed algorithm, Multi-Objective Genetics Algorithm (MOGA), and Surrogate Quadratic Programming (SQP) are combined and implemented on the Anisotropic Kriging model to choose a robust model with minimum error. The algorithm is then verified with FEM results and compared with other conventional optimization algorithms, such as the Genetics Algorithm (GA) and the Particle Swarm Optimization algorithm (PSO). The motor characteristics are analyzed using the Finite Element Method (FEM) and global map analysis to optimize the performance of the IPMSM for EV applications. A comparative study shows that the enhanced PMSM developed through the optimization process demonstrates superior performance indices for EVs. Full article

Interior permanent magnet (IPM) synchronous motors have gained widespread adoption in electric vehicles (EVs) owing to their durable rotor configurations, expansive operational speed range, and superior efficiency. Nonetheless, typical IPM motor designs frequently exhibit high torque ripple and constrained torque density. To address these issues, a torque enhancement method is introduced by applying both filleting and notching techniques to the stator core. These techniques help reshape the magnetic field directly at the stator, allowing for more precise control of torque production and torque ripple reduction while keeping the rotor structure unchanged. Design variables of the stator in a 12-slot/8-pole fractional-slot V-shaped IPM motor are optimized using a multi-objective genetic algorithm based on a sensitivity constraint for unidirectional operation. The electromagnetic performance of the motor is analyzed through 2D finite element simulations for both no-load and loaded scenarios. The proposed motor increases average torque by 2.45% and significantly reduces torque ripple by 47.73% compared to the conventional motor. These reflect a significant advancement in torque capability. Furthermore, the efficiency of the proposed motor reaches 93.8%. The findings suggest the potential of the proposed filleting and notching techniques for torque capability improvement in EV applications. Full article

Aero-engines, as complex systems integrating numerous rotating components and accessory equipment, operate under harsh and demanding conditions. Prolonged use often leads to frequent mechanical wear and surface defects on accessory parts, which significantly compromise the engine’s normal and stable performance. Therefore, accurately and rigorously identifying failure modes is of critical importance. In this study, failure modes are categorized into notches, scuffs, and scratches based on original bearing structure images. The YOLOv8 architecture is adopted as the base framework, and a Dilated Reparameterization Block (DRB) is introduced to enhance the Dilation-Wise Residual (DWR) module. This structure uses a large convolutional kernel to capture fragmented and sparse features in wear images, ensuring a wide receptive field. The concept of structural reparameterization is incorporated into DWR to improve its ability to capture detailed target information. Additionally, the standard convolutional layer in the head of the improved DWR-DRB structure is replaced by Spatial-Depth Convolution (SPD-Conv) to reduce the loss of wear morphology and enhance the accuracy of fault feature extraction. Finally, a fusion structure combining Focaler and MPDIoU is integrated into the loss function to leverage their strengths in handling imbalanced classification and bounding box geometric regression. The proposed method achieves effective recognition and diagnosis of mechanical wear fault patterns. The experimental results demonstrate that, compared to the baseline YOLOv8, the proposed method improves the mAP50 for fault diagnosis and recognition from 85.4% to 91%. Full article

This scoping review paper provides an overview of the evolution, the current stage, and the future prospects of fracture studies on composite laminates. A fundamental understanding of composite materials is presented by highlighting the roles of the fiber and matrix, outlining the applications of various synthetic fibers used in current structural sectors. Challenges posed by interlaminar delamination, one of the critical failure modes, are highlighted. This paper systematically discusses the fracture behavior of these laminates under mixed-mode and complex loading conditions. Standardized fracture toughness testing methods, including Mode I Double Cantilever Beam (DCB), Mode II End-Notched Flexure (ENF) and Mixed-Mode Bending (MMB), are initially discussed, which is followed by a decade-wide chronological analysis of fracture mechanics approaches. Key advancements, including toughening mechanisms, Cohesive Zone Modeling (CZM), Virtual Crack Closure Technique (VCCT), Extended Finite Element Method (XFEM) and Digital Image Correlation (DIC), are analyzed. The review also addresses recent trends in fracture studies, such as bio-inspired architecture, self-healing systems, and artificial intelligence in fracture predictions. By mapping the trajectory of past innovations and identifying unresolved challenges, such as scale integration, dataset standardization for AI, and manufacturability of advanced architectures, this review proposes a strategic research roadmap. The major goal is to enable unified multi-scale modeling frameworks that merge physical insights with data learning, paving the way for next-generation composite laminates optimized for resilience, adaptability, and environmental responsibility. Full article

Ultra-wideband (UWB) technology is a crucial facilitator for high-data-rate wireless communication due to its extensive frequency spectrum and low power consumption. Simultaneously, multiple-input multiple-output (MIMO) systems have garnered considerable attention owing to their capability to enhance channel capacity and link dependability. This article discusses the development of small, high-performance MIMO UWB antennas with mutual suppression capabilities to fully use the benefits of both technologies. Additionally, the suggested antenna features a straightforward design and dual-band-notched characteristics. The antenna structure includes two radiating elements measuring 85 × 45 mm². These elements use a rectangular patch provided by a coplanar waveguide (CPW). Double U-shaped slots are incorporated into the rectangular patch to introduce dual-band-notched properties, which help mitigate interference from WiMAX and WLAN communication systems. The antenna is fabricated on a Mylar^® polyester film substrate of 0.3 mm in thickness, with a dielectric constant of 3.2. According to the measurement results, the suggested antenna functions efficiently across the frequency spectrum of 2.29 to 20 GHz, with excellent impedance matching throughout the bandwidth. Furthermore, it provides dual-band-notched coverage at 3.08–3.8 GHz for WiMAX and 4.98–5.89 GHz for WLAN. The antenna exhibits impressive performance, including favorable radiation attributes, consistent gain, and little mutual coupling (less than −20 dB). Additionally, the envelope correlation coefficient (ECC) is extremely low (ECC < 0.01) across the working bandwidth, which indicates excellent UWB MIMO performance. This paper offers an appropriate design methodology for future flexible and compact UWB MIMO systems that can serve as interference-resilient antennas for next-generation wireless applications. Full article

Carbon fiber reinforced polymer (CFRP) composites are prone to developing localized material loss defects during long-term service, which can severely degrade their mechanical properties and structural reliability. To address this issue, this study proposes a multi-sensor synchronous monitoring method combining embedded fiber Bragg grating (FBG) sensors and surface-mounted electrical resistance strain gauges. First, finite element simulations based on the three-dimensional Hashin damage criterion were performed to simulate the damage initiation and propagation processes in CFRP laminates, revealing the complete damage evolution mechanism from initial defect formation to progressive failure. The simulations were also used to determine the optimal sensor placement strategy. Subsequently, tensile test specimens with prefabricated defects were prepared in accordance with ASTM D3039, and multi-sensor monitoring techniques were employed to capture multi-parameter, dynamic data throughout the damage evolution process. The experimental results indicate that embedded FBG sensors and surface-mounted strain gauges can effectively monitor localized material loss defects within composite laminate structures. Strain gauge measurements showed uniform strain distribution at all measuring points in intact specimens (with deviations less than 5%). In contrast, in defective specimens, strain values at measurement points near the notch edge were significantly higher than those in regions farther from the notch, indicating that the prefabricated defect disrupted fiber continuity and induced stress redistribution. The combined use of surface-mounted strain gauges and embedded FBG sensors was demonstrated to accurately and reliably track the damage evolution behavior of defective CFRP laminates. Full article

Background: Clear cell renal cell carcinoma with rhabdoid features (ccRCC-R) is a highly aggressive variant of renal cell carcinoma that carries a poor prognosis and limited treatment options. Methods: To better define the clinicopathologic and molecular landscape of ccRCC-R, we conducted an integrated clinicopathologic and molecular study of 17 tumors of ccRCC-R, utilizing comprehensive histomorphologic evaluation, immunohistochemistry, and targeted next-generation sequencing (NGS). Results: Histologically, all tumors demonstrated classic clear cell renal cell carcinoma morphology with focal to extensive rhabdoid differentiation, characterized by eccentrically located nuclei, prominent nucleoli, abundant eosinophilic cytoplasm, and paranuclear intracytoplasmic inclusion. Architectural alterations, including solid/sheet-like, alveolar/trabecular, and pseudopapillary growth patterns, were frequently observed. Immunohistochemically, tumors commonly exhibited loss of PAX8 and Claudin4 expression, preserved cytokeratin AE1/AE3 staining, and diffuse membranous CAIX expression. Frequent loss of SMARCA2 with retained SMARCA4 supported aberrations in chromatin remodeling. Unsupervised hierarchical clustering based on pathway-specific somatic mutations identified four distinct molecular subgroups defined by recurrent alterations in (1) DNA damage repair (DDR) genes, (2) chromatin remodeling genes, (3) PI3K/AKT/mTOR signaling components, and (4) MAPK pathway genes. Clinicopathologic correlation revealed that each subgroup was associated with unique biological characteristics and suggested distinct therapeutic vulnerabilities. Conclusions: Our findings underscore the molecular heterogeneity of ccRCC-R and support the utility of pathway-based stratification for guiding precision oncology approaches and biomarker-informed clinical trial design. Full article