Search Results (11,259)

Caffeoylquinic acids (CQAs), a class of phenolic acid metabolites widely distributed in plants, encompass 15 positional isomers from mono- to tetra-esters, with 5-O-caffeoylquinic acid (5-CQA) as the predominant form. The biosynthesis of 5-CQA from phenylalanine proceeds through five primary pathways, which are finely regulated by environmental, hormonal, and transcription factors from families such as MYB, WRKY, and bHLH. These regulators control 5-CQA synthesis by binding specifically to the promoter regions of key structural genes, including PAL, 4CL and HCT/HQT. Subsequently, 5-CQA serves as a central precursor for the biosynthesis of other CQAs. In terms of bioactivity, CQAs possess remarkable pharmacological activities, encompassing antioxidant, antimicrobial, anti-diabetic, anti-inflammatory and anti-tumor properties. For instance, anti-inflammatory effects are demonstrated by the ability of 5-CQA to reduce key pro-inflammatory cytokines (e.g., TNF-α and IL-1β) and downregulate the TLR4/NF-κB pathway. The synergistic action of 5-CQA with ultraviolet-A reduced succinate-coenzyme Q reductase activity by approximately 72%, highlighting its potential to disrupt bacterial metabolism and combat antibiotic resistance. Furthermore, 3,4,5-triCQA exhibits potent anti-influenza virus activity, potentially through a mechanism distinct from existing neuraminidase inhibitors. Beyond medicine, CQAs show promise in light industry. They serve as antibiotic alternatives in livestock feed to enhance gut health, extend food shelf life through their antioxidant activity, and function as active ingredients in UV-protective skincare formulations. CQAs also enhance plant stress tolerance to cold, arsenic, and pests by mechanisms such as scavenging reactive oxygen species and inhibiting pest mobility. While this review consolidates progress in the biosynthesis and bioactivity of CQAs specifically with caffeoyl substituents, future efforts should leverage modern biotechnological tools and interdisciplinary approaches to bridge critical knowledge gaps in their biosynthesis, transport, and clinical translation. Full article

Vascular Plant One-Zinc finger (VOZ) transcription factors are pivotal regulators of plant growth and stress adaptation, yet their functional roles in Gossypium hirsutum, a key fiber crop, remain poorly characterized. In this study, we systematically identified six VOZ genes in G. hirsutum and conducted a comprehensive analysis of their phylogenetic relationships, genomic distribution, promoter architecture, and expression profiles. Phylogenetic classification placed the GhVOZ proteins into three distinct clades, and chromosomal localization revealed that family expansion was likely driven by segmental duplication events. Promoter analysis uncovered an abundance of stress-related cis-regulatory elements, suggesting a potential role in abiotic stress signaling. Consistent with this, expression profiling demonstrated that GhVOZ1/3, GhVOZ2/4/5, and GhVOZ6 were specifically induced under drought, salt, and cold stress, respectively, with qRT-PCR further confirming their tissue-specific dynamic regulation under salt treatment. Furthermore, the GhVOZ family exhibited stage-specific expression patterns during somatic embryogenesis. GhVOZ1, GhVOZ3, and GhVOZ4 were upregulated at the early induction phase, implicating them in the initiation of cell reprogramming. In contrast, GhVOZ2 and GhVOZ4 showed sustained expression in embryogenic callus at later stages, suggesting a role in maintaining embryogenic competence, whereas GhVOZ5—preferentially expressed in non-embryogenic callus—may act as a repressor of embryogenesis. Synteny analysis further highlighted evolutionary conservation and subgenomic divergence of VOZ genes in G. hirsutum. Collectively, these findings establish GhVOZs as key regulators integrating abiotic stress response and somatic embryogenesis, providing a genetic framework for future functional studies and crop improvement. Full article

Mitigating wake effects between wind turbines is crucial for enhancing the overall output power of offshore wind farms. Therefore, optimizing turbine spacing and layout under turbulent conditions is essential. This study employs the NREL-5 MW wind turbine model to investigate the efficiency of a 3 × 3 wind farm. This research focuses on the influence of turbine spacing and layout on wake field distribution and output power characteristics under different turbulence intensities. A key innovation is the application of entropy production theory to quantify energy dissipation and wake recovery, providing a deeper understanding of the underlying mechanisms in energy losses. This research also introduces fatigue analysis based on the Damage Equivalent Load (DEL) method, revealing that staggered layouts significantly reduce cyclic loads and extend turbine lifespan. The results indicate that modifying the layout is a more effective strategy for enhancing the total power output of the wind farm, which proves to be more effective than altering the turbulence intensity. Specifically, staggered layout I (with a downstream stagger of 1.0 rotor diameter (D)) increases total output power by 28.76% (to 36.84 MW) and causes a 16.38% surge in power when the spacing increases to 5D. Expanding the wind turbine spacing mitigates wake interaction, resulting in a dramatic 59.84% power recovery for downstream wind turbines. The wind turbine’s lifespan is extended as a result of fatigue loads on the root bending moment being substantially reduced by the staggered layout, which alters the wake structure and stress distribution. The entropy production analysis shows that regions with high entropy production are primarily concentrated near the rotor and within the wake shear layer. The energy dissipation is substantially reduced in the case of staggered layout. These findings provide valuable guidance for the aerodynamic optimization and long-term operation design of large-scale wind farms, contributing to improved energy efficiency and reduced maintenance costs. Full article

Importin α (IMPα) proteins are key mediators of nucleocytoplasmic transport and play crucial roles in plant development and stress adaptation. Here, we performed a genome-wide identification of the IMPα gene family in Glycine max, followed by gene structure and conserved motif analyses, chromosomal distribution and duplication inference, synteny and selection (Ka/Ks) analyses, and expression profiling across tissues and stress conditions using public RNA-seq datasets and expression browsers. The GmIMPα genes exhibited diverse gene structures and conserved motifs, suggesting functional diversification within the family. Segmental duplication was identified as the main contributor to family expansion, and most duplicated gene pairs underwent purifying selection. Promoter analysis revealed numerous stress- and hormone-responsive cis-elements, implying complex transcriptional regulation. Expression profiling demonstrated that GmIMPα5 and GmIMPα7 were strongly induced under drought, heat, and salt stresses, indicating potential roles in abiotic stress tolerance. Collectively, our results provide a comprehensive framework for the evolution and functional divergence of the GmIMPα family in soybean and offer candidates for improving stress resilience. Full article

Population aging and rising rehabilitation demands highlight the need for advanced assistive devices to improve mobility in individuals with motor impairments. Existing back-support lifting nursing beds often lack adequate human–machine adaptability, safety, and emotional consideration. This study presents a human-centered, data-driven optimization pipeline that integrates behavior–emotion dual recognition, simulation verification, and parameter optimization with user demand mining, biomechanical simulation, and sustainable practices. The design utilizes GreenAI, focusing on low-power algorithms and eco-friendly materials, ensuring energy-efficient AI models and reducing the environmental footprint. A dual-channel data fusion method was developed, combining movement parameters from sit-to-lie transitions with emotional needs extracted from e-commerce reviews using the Term Frequency-Inverse Document Frequency (TF-IDF) and Latent Dirichlet Allocation (LDA) models. The fuzzy Kano model prioritized design objectives, identifying multi-position adjustment, joint protection, armrest optimization, and interaction comfort as key targets. An AnyBody-based human–device model quantified muscle (erector spinae, rectus abdominis, trapezius) and hip joint loads during posture changes. Simulations verified the design’s ability to improve load distribution, reduce joint stress, and enhance comfort. The optimized nursing bed demonstrated improved adaptability across user profiles while maintaining functional reliability. This framework offers a scalable paradigm for intelligent rehabilitation equipment design, with potential extension toward AI-driven adaptive control and clinical validation. This sustainable methodology ensures that the device not only meets rehabilitation goals but also contributes to a more environmentally responsible healthcare solution, aligning with global sustainability efforts. Full article

This study presents an initial feasibility concept paper for a proposed crosstie system, an innovative railroad crosstie reinforcement system designed to reduce the stresses transmitted to the underlying ballast. While not developed for a specific industry client, the proposed crosstie system lays the groundwork for patent application and potential commercialization, offering a novel alternative to conventional railroad construction. Finite Element Analysis demonstrated that this system can reduce effective stress on the ballast by up to 24%, effectively making train loads appear lighter to the substructure. The design of the proposed system focuses on mitigating the excessive stresses transmitted from crossties to the ballast layer in heavy axle load (HAL) freight rail operations. The goal was to create a reinforcement mechanism that is modular, compatible with existing track infrastructure, and capable of reducing maintenance costs by distributing loads more effectively across the ballast and subgrade. The findings indicate that this system is not only the most cost-effective and sustainable solution but also holds promise for reducing fixed stock investment, minimizing downtime for track maintenance, and enabling expanded rail network connectivity. These results support continued research and investment in the system’s development and deployment. Full article

This study examined residents’ perceptions, preferences, and experiences of urban green spaces in four regional units of the Region of Attica—West Athens, Central Athens, South Athens, and Piraeus—demonstrating how demographic diversity, urban morphology, and external stressors—such as extreme heat and the COVID-19 pandemic—shape green space use. The results show that, while green spaces are essential for health, well-being, and social cohesion, their distribution is uneven, which limits their availability (27.3%) and access (21.8%) to residents. Main concerns expressed by residents when visiting green spaces and open green spaces are poor maintenance (50.7%), lack of security (36.7%), and socially irresponsible behaviour (e.g., littering, vandalism) (32.8%). Extreme heat emerged as a major constraint on outdoor activities, particularly affecting women and the elderly. Household-associated outdoor areas (balconies, courtyards, and verandas) were highly valued (59.8%), highlighting the role of private green spaces in dense urban environments. Major metropolitan parks were the most visited and valued by residents for providing contact with nature (23.0%) and benefiting from stress relief (54.0%) while practicing their favourite activity, though their use was limited during heatwaves (30.3% of the residents do not visit). Most activities during and after the COVID-19 pandemic were reported unchanged, though reported increases in walking (34.3%) and park visits (28.3%) demonstrate the importance of green spaces in fostering urban resilience. However, the reported lack of engagement in gardening (48.0%), indoor plant care (41.2%) and bird/wildlife watching (58.3%) suggest missed opportunities for ecological and cultural enrichment. Overall, the study underscores the urgent need for integrated planning strategies to improve accessibility, maintenance, and equity in green space provision. By aligning with the sustainable development goals, the four regional units of the Region of Attica can transform its green infrastructure into an inclusive, resilient system that supports public health, social inclusion, and climate adaptation. Full article

Narrow-diameter implants (≤3.5 mm) have garnered significant attention due to their widespread application in areas with insufficient bone volume. However, their mechanical performance is limited. The cervical region, serving as a pivotal stress concentration zone, exhibits a thread form that directly modulates stress distribution and determines the long-term stability of the implant–bone interface. This study was designed to investigate the influence of varying thread forms and face angles on microstrain and stress distribution patterns in narrow-diameter implants (NDIs) and their adjacent cortical bone structures. Through systematic modification of implant thread forms and face angle parameters, finite element analysis (FEA) was employed to develop nine distinct implant models featuring varied geometric characteristics. Each model was implanted into Type III bone tissue, followed by the application of a 100 N occlusal force, including a vertical load and an oblique load deviated 30 degrees lingually from the long axis of the implants. Subsequent biomechanical evaluation quantified peak von Mises stress concentrations at the bone–implant interface, maximum equivalent elastic strain distributions in peri-implant bone tissue, and abutment stress profile characteristics. The results indicated that in the RB thread group, the optimal thread face angle parameter was 60 degrees; in the B thread group, this optimal thread face angle parameter was 45 degrees, whereas in the V thread group, the optimal thread face angle parameter was 30 degrees. Full article

The mechanical performance of cast iron is strongly governed by the morphology of its graphite phase, yet establishing a quantitative link between microstructure and macroscopic properties remains a challenge. In this study, a three-dimensional finite element method (FEM)-based micromechanical framework is proposed to analyze and predict the mechanical behavior of cast iron with representative graphite morphologies, spheroidal and flake graphite. Realistic representative volume elements (RVEs) are reconstructed based on experimental microstructural characterization and literature-based X-ray computed tomography data, ensuring geometric fidelity and statistical representativeness. Cohesive zone modeling (CZM) is implemented at the graphite/matrix interface and within the graphite phase to simulate interfacial debonding and brittle fracture, respectively. Full-field simulations of plastic strain and stress evolution under uniaxial tensile loading reveal that spheroidal graphite promotes uniform deformation, delayed damage initiation, and enhanced ductility through effective stress distribution and progressive plastic flow. In contrast, flake graphite induces severe stress concentration at sharp tips, leading to early microcrack nucleation and rapid crack propagation along the flake planes, resulting in brittle-like failure. The simulated stress–strain responses and failure modes are consistent with experimental observations, validating the predictive capability of the model. This work establishes a microstructure–property relationship in multiphase alloys through a physics-informed computational approach, demonstrating the potential of FEM-based modeling as a powerful tool for performance prediction and microstructure-guided design of cast iron and other heterogeneous materials. Full article

This paper extends the application of bimodulus elasticity theory by formulating a constitutive relation applicable to non-principal stress directions, building upon the established framework based on principal stresses. The paper develops four full-scale finite element models—the 3-node triangular, the 4-node quadrilateral, the 6-node triangular, and the 8-node quadrilateral elements—with the latter two showcasing higher precision in complex stress simulations. This formulation enables a more detailed analysis of material behavior under varying stress states. An effective iterative solution approach is introduced to address the nonlinearity of bimodulus materials, ensuring model convergence and reliability. The accuracy of the model has been verified through rigorous ANSYS 2022 R1 simulations, and the solution results have been compared with those in the existing literature, emphasizing the importance of the tension-to-compression modulus ratio in determining structural displacement and stress distribution. The developed models and methods provide useful numerical tools for the analysis and design of structures incorporating bimodulus materials. Full article

This study investigates the mechanical behavior and fatigue performance of orthotropic steel bridge decks, with a focus on rib-to-deck welded connections and the impact of geometric symmetry on stress distribution. Two full-scale models with full-penetration butt welds were tested under static compression loads, yielding failure forces of 27 kN (experimental) and 26 kN (analytical), with only a 3% difference. Finite element simulations using ANSYS 16.1 validated these results and enabled parametric studies. Rib plate thicknesses ranging from 5 mm to 9 mm were analyzed to assess their influence on stress distribution and deformation. The geometric ratio h′/tr, which reflects the symmetry of the trapezoidal rib web, was found to be a critical factor in stress behavior. At h′/tr = 38 (tr = 7 mm), compressive and tensile stresses are balanced, demonstrating a symmetric stress field; at h′/tr = 33 (tr = 8 mm), and fatigue performance at the RDW root drops by 47%. Increasing h′/tr improves fatigue life by increasing the number of load cycles to failure. Stress contours revealed that compressive stress concentrates in the rib plate above the weld toes, while tensile stress localizes at the RDW root. The study highlights how symmetric geometric configurations contribute to balanced stress fields and improved fatigue resistance. Multiple linear regression analysis (SPSS-25) produced predictive equations linking stress values to applied load and geometry, offering a reliable tool for estimating stress without full-scale simulations. These findings underscore the importance of optimizing h′/tr and leveraging structural symmetry to enhance resilience and fatigue resistance in welded joints. This research provides practical guidance for improving the design of orthotropic steel bridge decks and contributes to safer, longer-lasting infrastructure. Full article

The accurate real-time delineation of overburden failure zones, specifically the caved and water-conducted fracture zones, remains a significant challenge in longwall mining, as conventional monitoring methods often lack the spatial continuity and resolution for precise, full-profile strain measurement. Based on the hydrogeological data of the E9103 working face in Hengjin Coal Mine, a numerical calculation model for the overburden strata of the E9103 working face was established to simulate and analyze the stress distribution, failure characteristics, and development height of the water-conducting fracture zones in the overburden strata of the working face. To address this problem, this study presents the application of a distributed optical fiber sensing (DOFS) system, centering on an innovative fiber installation technology. The methodology involves embedding the sensing fiber into boreholes within the overlying strata and employing grouting to achieve effective coupling with the rock mass, a critical step that restores the in situ geological environment and ensures measurement reliability. Field validation at the E9103 longwall face successfully captured the dynamic evolution of the strain field during mining. The results quantitatively identified the caved zone at a height of 13.1–16.33 m and the water-conducted fracture zone at 58–60.6 m. By detecting abrupt strain changes, the system enables the back-analysis of fracture propagation paths and the identification of potential seepage channels. This work demonstrates that the proposed DOFS-based monitoring system, with its precise spatial resolution and real-time capability, provides a robust scientific basis for the early warning of roof hazards, such as water inrushes, thereby contributing to the advancement of intelligent and safe mining practices. Full article

Stress is a non-specific systemic response to internal or external challenges. Recent studies show that stress can disrupt iron metabolism and that iron dyshomeostasis is implicated in many diseases-particularly within the nervous system, where iron distribution and regulation intersect tightly with oxidative stress and inflammation. Activation of the hypothalamic–pituitary–adrenal (HPA) axis by stress can upregulate hepatic hepcidin and reprogram systemic iron fluxes, leading to functional iron deficiency and, in the brain, reduced iron availability, which affects myelination and neurotransmitter metabolism. Conversely, iron dyshomeostasis also contributes to neurodegenerative pathology. In this review, we synthesize recent evidence of how stress reprograms brain iron distribution and regulation, and we outline the mechanistic links between stress-induced iron dysregulation and neurological pathology. We also discuss the therapeutic implications (such as iron-chelation strategies) and highlight the three-way interplay among stress, iron metabolism, and neurodegeneration. These insights suggest that managing iron homeostasis may offer new therapeutic avenues for stress-related neural disorders. Full article

The moisture content of wood components varies with changes in the external environment, which significantly affects the mechanical properties, moisture stress, decay, drying shrinkage, and cracking of wood components. Therefore, calculating the moisture content distribution of the cross-section of wood components is an important basis for in-depth research on wood components. First, a hygroscopicity test was performed on 45° sector-shaped Chinese fir thin-plate specimens. The specimens were treated to an absolutely dry state and placed in two different environments. The average moisture content and moisture content gradient on the cross-section of the specimens were measured, and the spatial distribution and temporal variation in the moisture content were studied. A theoretical model for the moisture content distribution of wood was then derived based on food drying theory. Finally, the applicability of the theoretical model was verified through experiments, and the effects of the root order μ_n of the characteristic equation of key parameters, the size of the component, and the position of the component on the moisture content distribution were discussed for the theoretical model. During the hygroscopic process, the average moisture content of wood components increased continuously, but the growth rate gradually slowed. The surface moisture content rapidly reached the level of the external moisture content first, followed by the equilibrium moisture content within a few hours. Hygroscopic hysteresis evidently occurred within the wood, which may take dozens or even hundreds of days. When calculating the average moisture content model of cylindrical components, as well as those of the models of the spatial and temporal variation in the moisture content, it is sufficient to take the first 3 orders of the root μ_n of the characteristic equation of the first Bessel function J. The rate of moisture release of cylindrical components is faster than that of laminates because the ratio of the surface area to the volume of a cylinder is greater than that of a plate, and the former is twice that of the latter. The results revealed that the theoretical model for the moisture content distribution of wood has good accuracy and applicability. Full article

To elucidate the influence of the extrusion-based 3D printing of concrete on the tensile performance of polyethylene fibre-based engineered cementitious composites (PE-ECC), quantitative analyses of reinforcing filament alignment and pore morphology were carried out using backscattered electron (BSE) imaging and X-ray computed tomography (X-CT). A micromechanics analytical model based on microstructural characteristics was further employed to predict the tensile response of additively manufactured PE-ECC. Due to the extrusion process, fibres in 3D-printed PE-ECC were predominantly oriented along the printing path, resulting in a smaller average inclination angle compared with the randomly distributed fibres in cast specimens. Internal pores exhibited elongated flattened ellipsoidal shapes, with more pronounced anisotropy in axial lengths across the three principal directions. Taking the major semi-axis of the equivalent ellipsoidal voids as a representative pore parameter, the analytical model accurately reproduced the cracking strength, stress-strain evolution, and crack pattern of the printed PE-ECC. This extrusion process enhanced multiple cracking capacity and strain-hardening performance by improving fibre orientation, strengthening interfacial bonding, and altering matrix fracture toughness. The integration of micromechanical modelling with experimentally measured microstructural parameters effectively revealed the intrinsic mechanisms underlying the enhanced tensile behaviour of 3D-printed PE-ECC and provides theoretical support for the optimized design of fibre-reinforced cementitious composites in 3D printing. Full article