Search Results (6,073)

Drought is a major environmental constraint that disrupts photosynthetic processes. This study investigated the effects of foliar-applied commercial humic acid (HA) at different concentrations (1, 3 and 5 mg/mL) on the photosynthetic apparatus of sweet basil (Ocimum basilicum L. Italiano classico) under PEG-induced stress. The responses of the photosynthetic machinery were evaluated using chlorophyll a fluorescence analyses (JIP-test and PAM), leaf pigment composition, and assessments of membrane integrity. Drought stress caused pronounced alterations on both the donor and acceptor sides of photosystem II (PSII), including impaired Q_A⁻ reoxidation, reduced open PSII reaction centers (qP), diminished electron transport (ETo/RC, REo/RC), and substantial declines in performance indices (PI_ABS, PItotal). Energy dissipation increased (DI₀/RC), with regulated energy losses (F_NPQ) rising more strongly than non-regulated losses (F_NO). Drought also elevated oxidative stress markers (MDA and H₂O₂), leading to enhanced membrane injury. Among the tested concentrations, 5 mg/mL HA provided the most effective protection against drought stress. This treatment mitigated PEG-induced damage on both PSII donor and acceptor sides and increased the proportion of open reaction centers (qP). Improved PSII photochemistry corresponded with more efficient Q_A⁻ reoxidation, facilitated its interaction with plastoquinone, and caused the overall stabilization of photosynthetic functions under drought. The protective effects of HA were also evident for both PSI subpopulations. The enhanced tolerance was associated with the activation of antioxidant enzymes (CAT, SOD, APX) and the increased levels of anthocyanins and total phenolic content (TPC). In contrast, lower HA concentrations (1 and 3 mg/mL) provided insufficient protection. This study clearly demonstrates that HA enhances drought tolerance in basil in a concentration-dependent manner by protecting the structural and functional integrity of the photosynthetic apparatus, supporting its potential use as a foliar treatment to improve crop resilience under water-limited conditions. Full article

Maglev transportation has emerged as a new option for long-distance travel between cities with the rapid development of transportation infrastructure. The fatigue issues of the maglev train–track–bridge coupling system, induced by increased train speeds, have garnered considerable attention. This study focuses on the continuous girder bridge of low-to-medium-speed maglev dedicated lines. A multi-vehicle coupling model and a refined vehicle–track–bridge system were constructed. These were based on the maglev equivalent stiffness-damping theory. Dynamic stress is solved using the modal superposition method. Fatigue performance under multiple working conditions is then evaluated. This evaluation uses the rainflow counting method and Miner’s linear damage theory. Dynamic stress is solved using the modal superposition method, and fatigue performance under multiple working conditions is evaluated based on the rainflow counting method and Miner’s linear damage theory. Key findings include the following: Dynamic stress peaks in the track structure reach 29.4 MPa at high-strength bolts and 20.1 MPa at bridge fasteners, significantly exceeding those in the bridge, identifying these as fatigue-sensitive zones. During a single train passage, the stress amplitudes are mainly concentrated in the low-stress amplitude range, yet annual accumulated damage at the critical node track tie and bridge fastener junction reaches 4.99 × 10⁻⁴. Increasing the train speed to 160 km/h amplifies total damage at the track tie and bridge fastener junction by 365%, with nonlinear growth in fastener damage. This research provides theoretical insights for optimizing speed-up strategies and maintenance protocols in low-to-medium-speed maglev systems. Full article

The liver is a crucial metabolic organ in humans and is susceptible to oxidative stress, which can have an adverse impact on human health. Nutritional intervention with food-derived bioactive substances has the potential to improve liver health. However, their application in functional foods is limited by low oral stability and bioavailability. Therefore, a food-grade oral delivery system is required to enhance their stability and utilization efficiency. This review summarizes the research progress on the use of foodborne bioactive substances through food-grade oral delivery systems for nutritional intervention in liver oxidative stress. Firstly, this review introduces the physiological basis of liver-enriched active substances in food and the design principles of food-grade carriers. Furthermore, we summarize the types of delivery systems, including protein-based systems, polysaccharide and protein–polysaccharide composite systems, and lipid and emulsion systems, as well as emerging food-derived structural carriers. Additionally, we outline the methods for evaluating liver exposure, such as simulated digestion, intestinal transport, and hepatocyte uptake. Finally, we discuss the potential applications of machine learning in carrier design and process optimization, and analyze challenges, including large-scale production, sensory quality, and food regulations. This review provides a comprehensive theoretical and technical foundation for the development of food-grade oral delivery systems, aiming to bridge the gap between advanced delivery technologies and practical industrial applications in the functional food sector. The insights presented are expected to accelerate the development of next-generation liver health-promoting foods with high bioavailability and stable nutritional effects. Full article

In the context of reducing air transport emissions, operational costs and transitioning to more electric aircraft, there is a growing need to develop new ice protection systems. Resonant electromechanical de-icing (EM-DI) systems take advantage of the resonance to amplify vibration amplitudes applied through piezoelectric actuators, generating stress in the ice layer, enabling its removal. Research conducted on such systems has been focused on simplified or reduced models, and assessment of aircraft-level requirements has seldom been conducted. To overcome this shortcoming, this work proposes a pre-sizing methodology to evaluate the requirements (power consumption and piezoelectric mass) of EM-DI systems. After dividing the protected area into modules to cycle the aircraft de-icing, finite element models including the ice and the modules’ structure are developed. A modal analysis is performed to identify the extensional resonance modes that enable de-icing, and to calculate the necessary power and piezoelectric mass based on shedding criteria. The methodology is illustrated for two typical aircraft configurations: a jet engine single-aisle aircraft (SA) and a regional turboprop aircraft (TP). The results obtained for the EM-DI technology are promising, with apparent power estimates of as little as $2.7\mathrm{kVA}/{\mathrm{m}}^2$ for the SA and $1.28\mathrm{kVA}/{\mathrm{m}}^2$ for the TP. Full article

Grazing is a pervasive disturbance in arid ecosystems, but its effects on community-level coordination of plant hydraulic and economic traits remain poorly understood. Here, we investigated how long-term grazing alters community-weighted mean hydraulic and leaf economic traits in a desert steppe of Inner Mongolia, and how these shifts affect aboveground biomass (AGB) and water-use efficiency (WUE). Grazing drove a coordinated conservative shift in community hydraulic traits, including more negative osmotic potential at turgor loss point (ψ_tlp), increased cell wall rigidity (ε), and reduced leaf hydraulic conductance (K_leaf). Grazing also restructured trait–function relationships: under grazing, AGB was positively correlated with dehydration tolerance rather than transport efficiency, and WUE was tightly coupled with osmotic adjustment. Variance partitioning showed that hydraulic traits explained 57.4% of AGB variation under grazing, whereas economic traits dominated in the control site (74.5%). Our findings demonstrate that long-term grazing imposes a fundamental reorganization of community-level trait coordination, driving a transition from an efficiency-oriented to a safety-oriented strategy, and highlight the central role of hydraulic traits in mediating ecosystem function under combined stress. Full article

Water stress is intensifying worldwide, increasing the need for efficient desalination and water purification technologies. Although commercial nanofiltration membranes such as NF90 exhibit high separation performance, their transport properties remain governed by permeability–selectivity trade-offs, and their surface characteristics offer limited tunability for application-specific requirements. Here, a commercial NF90 polyamide thin-film composite nanofiltration membrane was surface modified by depositing ultrathin ZnO coatings via RF sputtering (30–120 s) and evaluated in terms of surface properties, water permeate flux, and NaCl rejection. X-ray diffraction confirmed the formation of crystalline Wurtzite ZnO with preferential (002) orientation. ZnO deposition markedly increased surface hydrophobicity, raising the water contact angle from 52.5 ± 2.0° for the unmodified membrane to 140.4 ± 3.9° after 120 s of deposition. Hydraulic performance decreased after modification, with water permeate flux reduced by approximately 47–50% relative to pristine NF90. In contrast, NaCl rejection increased with ZnO deposition time, particularly at lower operating pressures, and tended to plateau at higher pressures. The Spiegler–Kedem model accurately described experimental rejection-flux behavior. Overall, RF sputtering of ZnO is a feasible post-fabrication route to tune NF membrane selectivity, while introducing a clear trade-off with permeate flux. Full article

The flow behavior of montmorillonite (MMT) slurries with a volume fraction of $6.6\times {10}^{-4}$ to $1.6\times {10}^{-3}$, coagulated in 1.0 M NaCl, was investigated across laminar, transitional and turbulent regions using a closed-loop circular pipeline system equipped with dual pressure transducers and a flow meter. In the laminar region, the linearized approximation of the Bingham model was applied to extract yield stress and plastic viscosity, which were subsequently used to estimate friction losses as a function of the Reynolds number. The predicted friction loss calculated using the Hedström number and the Bingham model showed excellent agreement with experimental data. Furthermore, the critical Reynolds number indicating the transition from laminar to turbulent flow was confirmed to increase with increasing yield stress. This trend is qualitatively consistent with flow stability predictions. Notably, the plastic viscosity obtained by this method was significantly lower than values estimated from sediment volume fractions using conventional viscosity correlations based on an effective volume fraction of flocs. These insights into the flow resistance of coagulated clay suspensions are useful for improving the design and operation of water purification, slurry transport, and solid–liquid separation processes. Full article

Attention-deficit/hyperactivity disorder (ADHD) is a common neurodevelopmental disorder in which dopaminergic dysfunction plays a central role. Beyond its neurotransmitter function, dopamine is a redox-active molecule capable of generating reactive oxygen species and toxic intermediates, particularly when cytosolic dopamine accumulates because of altered vesicular storage or transporter imbalance. This review examines whether dopamine-derived oxidative stress may represent a biologically plausible and testable framework for ADHD by integrating current evidence on dopamine metabolism, oxidative stress, and neuronal dysfunction, while distinguishing direct evidence from indirect and translational findings. A structured literature search was conducted in PubMed, Scopus, and Web of Science for relevant English-language studies published between January 2000 and March 2026. The available evidence suggests that dopamine-derived oxidative stress may help link disturbed dopamine handling to protein modification, lipid peroxidation, mitochondrial dysfunction, synaptic inefficiency, and circuit-level abnormalities in ADHD. Although direct in vivo evidence remains limited, this framework may help distinguish dopamine-derived oxidative stress from more general oxidative imbalance in ADHD and may guide future biomarker-based, experimental, and translational research. Full article

Natural products remain a major source of anticancer agents, yet freshwater organisms are largely unexplored. Building on our previous evidence that planarian mucus exerts cytostatic and cytotoxic effects on cancer cells, we investigated the involvement of endoplasmic reticulum stress and unfolded protein response (UPR) pathways. Mucus-induced cytotoxicity is ROS-dependent and associated with depletion of intracellular reduced glutathione (GSH), not through inhibition of the System Xc⁻ transporter but potentially associated with upregulation of CHAC1, a glutathione-degrading enzyme. Mucus fractionation based on molecular weight identified the high-molecular-weight crude fraction as the one containing the bioactive entity, reproducing the effects of whole mucus. Treatment with this fraction early activates the PERK–ATF4 branch of the UPR, which could be responsible for driving CHAC1 induction. Moreover, ATF4 enhances DDIT3 expression, and activates a compensatory NRF2-dependent antioxidant response. At a later stage mucus also activates the IRE1α–XBP1 axis, with no ATF6 involvement, indicating selective UPR engagement in response to oxidative and lipid stress. Overall, our data are consistent with a potential PERK–ATF4–CHAC1–GSH self-sustaining axis promoting oxidative stress that culminates in cell death, supporting the potential of planarian mucus as a source of pleiotropic bioactive compounds, although the molecular identity of the active component(s) remains still unresolved. Full article

The structural and electrical transport properties of brucite [Mg(OH)₂] were investigated by virtue of in situ Raman spectroscopy and alternating-current impedance spectroscopy under conditions of 0.5–20.2 GPa, 298–873 K, and different hydrostatic environments using a diamond anvil cell (DAC). Under the non-hydrostatic condition, the emergence of new Raman peaks and discontinuities in Raman shifts, FWHMs, as well as electrical conductivity well disclosed a hydrogen-disordering structural phase transition in brucite from the ordered ($P\overline{3}m1$ symmetry)–disordered ($P\overline{3}$ symmetry) structure at 5.7 GPa. Under hydrostatic condition, this transformation occurs at a lower pressure of 3.6 GPa using the 4:1 methanol–ethanol mixture (ME) as the pressure-transmitting medium (PTM), which can be attributed to the influence of deviatoric stress within the sample chamber. The reversibility of this transformation is confirmed by the recovery of Raman peaks and electrical conductivity upon decompression. Furthermore, the high-temperature and high-pressure electrical conductivity results clearly revealed a negative Clapeyron slope for the hydrogen-disordering transformation in brucite, and the corresponding high P–T phase diagram was established for the first time at pressures up to 7.0 GPa and temperatures up to 873 K, which can be expressed as $P \left(\mathrm{GPa}\right) = 8.664 (\pm 1.511) - 0.008 (\pm 0.002) T \left(\mathrm{K}\right)$. These results provide direct experimental constraints on the high-pressure phase stability and structural phase transition of brucite and offer an important reference for understanding the behavior of other hydroxide minerals under extreme conditions. Full article

This study numerically investigates the aerodynamic and thermal interactions between a full-scale metro train and the surrounding airflow within a confined tunnel environment using steady-state Reynolds-averaged Navier–Stokes (RANS) simulations. The six-car train, with a total length of 108 m and a cross-sectional area of 5.97 m², operates in a tunnel with a 9.83 square meter cross-section, resulting in a high blockage ratio of approximately 60 percent. The Shear Stress Transport (SST) k–ω turbulence model and a high-resolution finite-volume mesh comprising over 8.5 million elements were employed to capture detailed near-wall phenomena. Six representative motion scenarios were analyzed, including early acceleration, peak cruising, and deceleration phases, with realistic thermal boundary conditions applied by assigning the tunnel air temperature as 29.2 °C and the train surface temperature as 35.0 °C. Velocity, pressure, temperature, and turbulence kinetic energy distributions were extracted from both longitudinal and cross-sectional planes. In addition to visual contour assessments, pointwise and spatially averaged field data were examined to quantify the development of airflow structures, pressure distribution, and thermal behavior. The results reveal speed-dependent aerodynamic resistance, pronounced recirculation and stagnation zones around the train nose and tail, and variations in convective heat transfer rates that evolve with train velocity. These findings provide insights into tunnel ventilation design and thermal management for underground metro operations, representing a novel integration of full-scale computational fluid dynamics (CFD) with thermal characterization under realistic conditions. Full article

Tryptophan (Trp) metabolism sits at the intersection of nutrition, the microbiome, mucosal immunity, and tumor adaptation. The broad observation that microbial indoles can support barrier function, whereas tumors exploit kynurenine-pathway metabolism to suppress immunity, is already established in publications. The specific contribution of this review is to organize that literature into a context- and network-based translational framework. Rather than treating indoleamine 2,3-dioxygenase 1 (IDO1) as a single bottleneck, we frame tumor Trp metabolism as a compensatory system linking IDO1, tryptophan 2,3-dioxygenase (TDO2), interleukin-4-induced gene 1 (IL4I1), amino-acid transport, amino-acid stress sensing, and downstream aryl hydrocarbon receptor (AHR) signaling. In healthy tissue, especially the gut, dietary Trp and microbiota-derived indoles can promote epithelial integrity, interleukin-22 (IL-22)-associated programs, and mucosal restraint. In tumors, the same substrate pool is redirected toward Kynurenine, kynurenic acid, indole-3-pyruvate, and related catabolites that impair cytotoxic lymphocytes, expand regulatory T-cell (Treg) and suppressive myeloid compartments, and reinforce invasion and treatment resistance. We also argue that the potential metabolite biomarker interpretation should be context-dependent. Finally, we propose a clinical-context–specific framework for intervention. Dietary and microbiome-based strategies may be most effective in prevention, premalignant states, or supportive care, whereas established cancers are more likely to require biomarker-guided targeting of tumor-associated catabolic pathways and convergent signaling mechanisms. The “paradox” is therefore not that Trp changes chemistry across settings, but that the same nutrient is routed through different cellular contexts, enzymes, ligands, and cell states. Full article

Micro- and nanoplastics (MNPs) are ubiquitous environmental pollutants recognized as emerging and relevant risk factors for numerous human diseases, including cardiovascular diseases. MNPs enter the human body through ingestion, inhalation, and dermal penetration, and their toxicity varies according to size, shape, and chemical composition, most notably between microplastics (>1 µm) and nanoplastics (<1 µm), which differ in cellular uptake mechanisms and biodistribution. Recent evidence has confirmed their presence in cardiac and vascular tissues, raising significant concerns about their potential impact on human health. This review summarizes current knowledge on MNP exposure sources, physicochemical properties, and systemic bioavailability, with a particular emphasis on the mechanisms of transport that facilitate their deposition within the myocardium and vasculature. It further addresses a broad spectrum of cardiotoxic effects, including oxidative stress, mitochondrial injury, immune activation, ion channel disruption, cell death, and fibrosis. Endothelial dysfunction, vascular injury, and pro-atherogenic activity are also discussed. In addition to outlining existing detection techniques and emerging in vitro models, the review highlights initial steps toward the development of preventive strategies. Concluding with key knowledge gaps and future research directions, this article underscores the urgent need for standardized measurement tools, deeper insights into damage mechanisms, and clinical interventions to prevent MNP-induced cardiovascular diseases. Full article

Hydrogen transport under high-pressure conditions poses significant challenges for pipeline materials and structural design. Existing studies on PA12-based systems are primarily limited to material-level characterization, with insufficient validation at the pipeline scale. To address this gap, this study presents the design and system-level experimental validation of an all-thermoplastic composite hydrogen pipeline. A full-scale DN50 pipeline, consisting of a PA12 liner and a ±54° filament-wound carbon fiber-reinforced layer, was fabricated and tested under hydrogen pressures up to 10 MPa, including long-term exposure and cyclic loading. The results indicate stable deformation behavior and low hydrogen permeation (~10⁻¹⁴ mol·m/(m²·s·Pa)) within the investigated pressure range, with a burst pressure exceeding 60 MPa. A transition from stable to accelerated deformation was identified at elevated pressure, indicating a structural operating limit. Post-test observations reveal that interlaminar damage, rather than primary interface failure, governs long-term degradation. Based on these findings, a design framework integrating stress-based, deformation-based, and damage-based criteria is proposed. This work extends PA12-based hydrogen pipeline research from material-level understanding to system-level validation and provides practical guidance for structural design and performance evaluation. Full article

Drought frequently threatens the yield and quality of Carya cathayensis Sarg. cultivated in mountainous regions. To search for effective drought-resistant regulators is of great significance for alleviating short-term seasonal drought in C. cathayensis during dry seasons, thereby stabilizing its yield and quality. Silicon dioxide nanoparticles (SiO₂ NPs) mitigate abiotic stress in plants. To give insight into the regulatory role of SiO₂ NPs in mitigating drought stress, polyethylene glycol 6000 (PEG-6000) was used to simulate varying degrees of drought conditions, and the growth phenotype, photosynthetic physiological characteristics, antioxidant defense system, and cellular ultrastructure of C. cathayensis leaves were analyzed to evaluate the impacts of foliar-applied exogenous SiO₂ NPs. The results indicated that, compared with severe drought, 200 mg/L SiO₂ NP application to plants under severe drought treatment significantly increased superoxide dismutase and peroxidase activities and chlorophyll and nitrogen contents, while malondialdehyde levels decreased. Furthermore, SiO₂ NP application notably enhanced the net photosynthetic rate, stomatal conductance, and electron transport efficiency. This effectively alleviated both stomatal and non-stomatal limitations, thereby mitigating drought-induced photosynthetic inhibition. Additionally, Transmission electron microscopy revealed that SiO₂ NPs effectively preserved the structural integrity of chloroplasts, mitochondria, and nuclei, reducing drought-induced ultrastructural damage. In conclusion, exogenous SiO₂ NPs enhance drought tolerance in C. cathayensis by synergistically modulating photosynthesis, antioxidant defense, and cellular structural stability. Full article