Search Results (11,353)

Background/Objectives: High-altitude pulmonary edema (HAPE) remains a serious condition with limited preventive options. This study evaluated the prophylactic protective effects of nebulized human umbilical cord mesenchymal stem cell-derived extracellular vesicles (hUC-MSC-EVs) in a rat model of hypobaric hypoxia-induced lung injury and explored potential mechanistic clues, with a focus on oxidative stress and TEK/Tie2 signaling. Methods: Rats were exposed to hypobaric hypoxia (47 kPa; 9.7% O₂) for 72 h and received prophylactic nebulized hUC-MSC-EVs (300 μg/rat). Lung injury was evaluated by histopathology, wet-to-dry ratio, and bronchoalveolar lavage fluid (BALF) protein concentration. Invasive pulmonary function indices were measured using a forced oscillation system. BALF cytokines (TNF-α, IL-6, and IL-10), reactive oxygen species (ROS), and TEK/Tie2 expression in lung tissue were assessed. In addition, transcriptome sequencing (RNA-seq) was performed to characterize global transcriptional changes. N-acetylcysteine (NAC), a classical antioxidant, was included as an auxiliary mechanistic intervention to assess the association of ROS with TEK/Tie2 changes. Results: Compared with hypoxia controls, prophylactic nebulized hUC-MSC-EVs reduced histopathological injury, pulmonary edema, and barrier leakage, and improved pulmonary function indices. hUC-MSC-EV intervention also attenuated inflammatory responses in BALF, with decreased TNF-α and IL-6 and increased IL-10. Hypobaric hypoxia increased ROS accumulation and decreased TEK/Tie2 expression, whereas nebulized hUC-MSC-EVs reduced ROS and partially preserved TEK/Tie2 expression. NAC pretreatment similarly reduced ROS and was accompanied by Tie2 preservation. Conclusions: Prophylactic nebulized hUC-MSC-EVs mitigated hypobaric hypoxia-induced lung injury, accompanied by reduced oxidative stress, improved vascular barrier integrity, and preservation of TEK/Tie2 expression. These findings support nebulized hUC-MSC-EVs as a potential lung-targeted prophylactic strategy for hypobaric hypoxia-induced lung injury and suggest that ROS imbalance may be associated with Tie2 preservation. Full article

Folic acid, an essential vitamin for human health, plays a crucial role in maintaining intestinal homeostasis and functional stability, and its absorption is frequently impaired in Crohn’s disease, where it is closely associated with clinical complications and nutritional management. Nevertheless, the quantitative relationship between the complex multiscale architecture of intestinal villi, their morphological dynamics, and the efficiency of folic acid absorption remains insufficiently understood, primarily because existing studies rely on oversimplified representations of villous geometry and neglect the internal vascular structure, thereby limiting their ability to capture the coupled transport processes within individual villi. While existing studies have considered the influence of villous morphology on intestinal absorption, they generally rely on oversimplified representations and do not account for the internal structural organization of villi. This study aims to elucidate the quantitative relationship between villous multiscale architecture and folic acid absorption efficiency under pathological conditions of Crohn’s disease. Herein, a two-dimensional multiphysics numerical model is developed that integrates the external environment of intestinal villi with their internal microstructure, simulating folic acid transport via diffusion and Michaelis–Menten kinetics, coupled with convection–diffusion in the microvascular network under Stokes flow conditions. We find a reduction in villus height to 400 μm or local blood flow velocity to 0.01 mm/s leads to a marked decrease in folic acid absorption capacity, by approximately 57% and 50%, respectively. These changes are primarily attributed to inflammation-induced villus atrophy, which reduces the effective absorptive surface area. Furthermore, reduced blood flow velocity lowers the Peclet number, facilitating the accumulation of folic acid within the villi, which in turn further reduces the efficiency of folic acid absorption. This work contributes to a deeper understanding of how diseases affect the absorptive function of intestinal villi and provides a theoretical basis for the pathological mechanisms of the gut. Full article

Natural hydrogen is regarded as a potential resource for the global energy transition, and its accumulation is closely linked to water–rock reactions involving Fe²⁺ bearing minerals and effective sealing conditions. The Liaohe Basin, located on the northeastern margin of the North China Craton within a key metallogenic belt, is surrounded by sedimentary-metamorphic iron deposits and is a potential area for natural hydrogen accumulation. In this study, aeromagnetic and satellite gravity data were integrated to estimate basement depth through gravity interface inversion, followed by three-dimensional magnetic susceptibility and density inversion and structural–mineralization correlation analysis. The results reveal strong basement heterogeneity. Iron-rich anomalous bodies show clustered and belt-like to dome-like distributions, mainly along the transitional zone between deep depressions and basement uplifts. Combined density–magnetic zonation suggests that high-density, high-magnetic units may correspond to iron-rich bodies, whereas high-magnetic, low-density units likely indicate fractured and altered fluid pathways. Based on the measured results of surface hydrogen concentration, it is inferred that the high magnetic anomaly in the uplift transition zone at the edge of the depression might be the coupling area of iron-rich rock bodies and channel zones, which is the priority response area of natural hydrogen in the Liaohe Basin, China. Full article

Weak-echo ship target detection in GNSS-based bistatic synthetic aperture radar is severely limited by the coupled effects of burst-type strong windows and polarization mismatch, cross-frequency mis-registration, and long-sequence chain drift in dual-frequency dual-polarization observations. To address these issues, this paper proposes DFDP-QuadDiff, a dual-frequency dual-polarization quad-differential framework for weak-echo ship target detection using B1/B3 × horizontal–horizontal (HH)/vertical–vertical (VV) four-channel complex range-time data. The proposed framework integrates polarization-consistency-driven strong-window suppression, intra-band adaptive polarimetric synthesis, joint delay–Doppler–phase cross-frequency registration, segment-wise Jones drift calibration, and quality-aware final fusion in a unified hierarchical processing chain. In this way, multi-source inconsistencies are progressively constrained and suppressed from the polarization level to the segment level before final accumulation and detection are performed. Experimental results on self-developed four-channel GNSS-S demonstrate that, relative to the best raw single-channel result, the proposed framework increases the median SCR from 6.51 dB to 9.04 dB (+2.53 dB), improves the P10 SCR from −1.76 dB to 3.05 dB (+4.81 dB), and raises the track continuity from 0.85 to 0.97. In addition, the standard deviation of segment-wise delay drift is reduced from 0.97 bin to 0.29 bin, and positive multi-scale accumulation gains are maintained up to the second-long integration range. These results indicate that the proposed framework not only substantially enhances the stability, continuity, and long-time integrability of weak-target responses under low-SNR maritime conditions, but also maintains robust gains under weak-visibility, interference-dominant, and mismatch-sensitive local conditions in the stratified evaluation, thereby establishing a physically interpretable and implementation-ready solution for collaborative weak-target detection in dual-band dual-polarization GNSS-S. Full article

To address the prominent fatigue failure risk of planetary gears in power-split hybrid buses and the lack of quantitative damage analysis across various operating modes in existing studies, this paper focuses on the front planetary gear set of a power-split hybrid bus. Based on a full-vehicle co-simulation model, loads under full operating conditions are decomposed into 11 operating modes, mode-switching loads are analyzed and extracted, and mode-decomposed and mode-switching fatigue loading spectra are compiled. Fatigue simulation is then conducted using Miner’s linear damage accumulation rule. Results show that the sun gear directly coupled to motor is the system’s most fatigue-susceptible component, exhibiting significant asymmetric unilateral tooth flank damage. The hybrid electric vehicle (HEV) mode contributes approximately 88% of total damage to the sun gear’s right flank, dominating system fatigue damage. Transient mode-switching conditions account for approximately 60% of total damage to the sun gear’s left flank, serving as the core damage source. Compared with the traditional full-condition merging method, the proposed mode-decomposed method improves the conservatism of life prediction. This work provides methodological support for refined strength design and targeted optimization of power-split hybrid transmission systems. Full article

Internal phosphorus loading is a key process sustaining eutrophication in stratified Baltic Sea coastal systems, yet its long-term dynamics in the Archipelago Sea remain poorly quantified due to limited deep-water monitoring and the absence of sediment time series. This study provides a multidecadal assessment of internal loading from the early 1980s to 2025 using two complementary indicators: (i) seasonal accumulation of total phosphorus in the surface layer (ΔTP) and (ii) the covariation between near-bottom oxygen depletion and dissolved inorganic phosphorus (DIP) release. Temporal associations with external phosphorus inputs from marine fish farming—highly variable during the study period—were analyzed to evaluate whether cumulative loading trajectories coincided with phases of intensified ΔTP. New measurements of drifting filamentous macroalgae from 2025 were additionally used to assess their seasonal contribution to the internal phosphorus pool and their relevance for mitigation. Results show a pronounced multidecadal strengthening of internal loading signals in the mid and inner Archipelago Sea. At the Seili station, ΔTP increased by approximately 6.8 µg L⁻¹ (≈3.4-fold) since the early 1980s. This trend coincided with long-term deterioration of near-bottom oxygen conditions and increasing DIP concentrations, consistent with enhanced sediment phosphorus release. Although cumulative aquaculture loading exhibited simple correlations with ΔTP, detrended analyses indicate that these relationships largely reflect shared long-term trends rather than direct causal linkages. Drifting filamentous macroalgae formed a substantial seasonal phosphorus reservoir (≈146 t P). Overall, internal phosphorus input to the Archipelago Sea has intensified markedly—by an estimated ~70% since the 1980s—highlighting the growing importance of sediment–water feedbacks and legacy phosphorus. Effective mitigation therefore requires strategies that address both internal recycling processes and external nutrient inputs. Targeted removal of drifting filamentous macroalgae may provide a complementary nutrient-export pathway in coastal management. Full article

This study investigates the thermo-mechanical response of geocell-reinforced concrete pavements through scaled model tests and three-dimensional finite element analyses. Static, thermal, traffic, and coupled temperature–loading tests were conducted to clarify the deformation evolution, strain distribution, and damage-related response of the reinforced structure. The results show that, under static loading, pavement settlement evolves through three stages, namely initial compaction, plastic development, and stable strengthening, indicating progressive mobilization of geocell confinement. Under thermal loading, slab strain exhibits pronounced spatial and temporal non-uniformity, and the slab center is identified as the thermally sensitive zone. Under coupled temperature–loading conditions, both strain and settlement show a non-monotonic response near 1.1–1.3 kN, suggesting a potential damage-initiation range. Post-test crack observations further provide direct qualitative evidence that local cracking damage occurred in the slab under representative loading conditions. Under traffic loading, permanent deformation accumulates with load repetitions and is highly sensitive to load amplitude, indicating a load-sensitive transition in cumulative deformation behavior rather than a definitive fatigue threshold. Numerical results further show that geocell reinforcement reduces central settlement by 17.4% relative to plain concrete pavement and by 7.6% relative to doweled pavement, while producing a smoother deflection basin and a more uniform stress distribution. Parametric analyses indicate that the optimum geocell height is approximately one-third of the slab thickness; beyond this range, the marginal reinforcement benefit decreases. Overall, the results demonstrate that geocell reinforcement can effectively improve load transfer, deformation compatibility, and thermo-mechanical stability of concrete pavements under the investigated conditions. Full article

Chronic stress is a time-dependent condition characterized by sustained dysregulation across neural, autonomic, and endocrine systems, with important consequences for both health and socioeconomic outcomes. Unlike acute stress, which is typically characterized by short-lived physiological activation, chronic stress reflects an accumulated allostatic load and a longer-term recalibration of stress response systems. Recent advances in physiological sensing and artificial intelligence (AI) have supported the development of computational approaches for chronic stress detection using electroencephalography (EEG), heart rate variability (HRV), photoplethysmography (PPG), electrodermal activity (EDA), and wearable multimodal platforms. This narrative review examines current AI-based studies through three main inferential paradigms: resting baseline dysregulation, longitudinal physiological monitoring, and reactivity-based inference. Across modalities, classical machine learning (ML) methods, particularly support vector machines (SVMs) and tree-based ensembles, remain the most commonly used approaches, largely because available datasets are small and most pipelines still depend on engineered features. Deep learning (DL) methods are beginning to emerge, but their use remains constrained by the lack of large, standardized, longitudinal datasets specifically designed for chronic stress research. Major challenges include ambiguity in stress labeling, limited longitudinal validation, circadian confounding, inter-individual variability, and small cohort sizes. Future progress will depend on standardized datasets, biologically grounded multimodal integration, hybrid baseline-reactivity modeling, adaptive personalization, and more interpretable AI systems. Greater emphasis is also needed on clinical relevance and generalizability if AI-based chronic stress monitoring is to move beyond experimental settings. Full article

The increasing prevalence of obesity and Alzheimer’s disease (AD) in the aging population underscores an urgent need to understand the common cellular and metabolic mechanisms they share. Accumulated evidence suggests that overlapping metabolic disturbances contribute to the pathogenesis of these two conditions. In this review, we highlight key underlying interconnecting metabolic pathways: (1) adipose-brain crosstalk mediated by adipokines and adipose tissue-derived extracellular vesicles that can modulate neuronal function and amyloid pathology, (2) dysregulated lipid metabolism affecting cholesterol, sphingolipids, and phospholipids and thereby promoting inflammation, amyloid precursor protein processing, and tau hyperphosphorylation, (3) impaired glycolysis and insulin resistance, which accelerate both obesity and neurodegenerative processes, (4) mitochondrial dysfunction marked by disrupted tricarboxylic acid cycle enzymes and electron transport chain complexes, leading to elevated reactive oxygen species and driving both obesity and AD pathology, and (5) gut microbiota dysbiosis, which can trigger inflammation as well as amyloid and tau aggregation. Together, these mechanisms show that metabolic alterations appear early, preceding clinical disease, and that understanding these underlying connections can provide strategies to protect metabolic health and prevent disease progression. Full article

Photovoltaic (PV) arrays frequently operate under non-uniform environmental conditions, including partial shading, dust accumulation, and temperature differences across the array. These factors introduce an electrical mismatch among PV modules, considerably reducing overall power output. This study proposes a self-healing reconfiguration strategy that mitigates mismatch losses by dynamically redistributing PV modules across array strings based on irradiance levels. The main goal is to balance the current generation among strings and demonstrate performance improvements within scenarios characterised by highly uneven irradiance patterns under non-uniform operating conditions. The effectiveness of the proposed method is evaluated through simulations conducted using MATLAB R2025b (MathWorks, Natick, MA, USA) under several environmental scenarios. Deterministic shading patterns—including row shading, column shading, diagonal shading, and irregular dust distributions—are first analysed to investigate the behaviour of the PV array under regulated conditions. In addition, a statistical analysis of 100 randomly generated irradiance scenarios is carried out to assess the method’s robustness. Finally, realistic desert-dust patterns representative of environmental conditions in Saudi Arabia are used to evaluate the practical usefulness of the proposed approach. Simulation findings show that the self-healing reconfiguration strategy reduces mismatch effects and improves current balance within the PV array, enabling operation closer to the optimal power point under non-uniform irradiance conditions. These results indicate that the proposed method boosts current balance among PV strings and increases power extraction under strongly non-uniform irradiance scenarios. Full article

Temperature is a major determinant of plant metabolic plasticity, yet its role in directing volatile and semi-volatile specialized metabolism in Ginkgo biloba remains poorly understood. In this study, we investigated how contrasting low- and high-temperature treatments reshape secondary metabolite contents in G. biloba microclones cultivated in vitro. Plants were exposed to cold (+3 °C) and heat (+30 °C) conditions, and their responses were analyzed using GC–MS profiling, anatomical measurements, chlorophyll fluorescence, and multivariate statistics. Cold treatment selectively increased the abundances of monoterpenes (13.22%) and sesquiterpenes (13.83%), with the strongest accumulation of caryophyllene, eucalyptol, and (1S)-camphor. In contrast, heat treatment reduced ester content to 3.73% and strongly enriched oxy-sesquiterpenes (46.50%) and lactone/ketone/spiroketone (29.54%) contents. The enhanced accumulation of isocalamendiol, isoshyobunone, cyclohexanone derivative, dehydroxy-isocalamendiol, and (+)-2-bornanone was observed under heat. According to the multivariate analysis, control plants were associated with traits reflecting optimal physiological performance, including greater parenchyma, phloem, and xylem thickness, larger vascular bundles, longer stomata, and higher NPQ, qN, Y(NPQ), and F_v/F_m. Cold-treated plants showed thicker epidermis and sclerenchyma, higher stomatal density and width, elevated Y(NO), and an enrichment of esters and terpenoids, whereas heat-treated plants were characterized by thicker adaxial and abaxial epidermis, increased mesophyll thickness, and higher levels of oxygenated metabolites. These findings expand current knowledge beyond terpene trilactones and flavonoids and identify Ginkgo microclones as a useful in vitro model for temperature-guided metabolic reprogramming and targeted metabolite enrichment. Full article

Fine migration is widely recognized as a primary cause of production decline in unconsolidated sandstone reservoirs. Migrated fines may accumulate within pore throats and obstruct flow channels, or they may be transported into the wellbore with the produced fluids, leading to operational issues such as wellbore plugging, pump sticking, and equipment abrasion. Despite extensive studies on fine migration, the role of particle wettability has received limited attention. In this study, the mineralogical composition of formation particles was first characterized using X-ray diffraction (XRD) and quantitative clay analysis. Surface modification experiments were then conducted to investigate the effect of hexadecylamine (HDA) on particle wettability and to determine the optimal reaction conditions. Surface characterization techniques were employed to elucidate the modification mechanism. Subsequently, sand-packed tube displacement experiments were performed to evaluate the influence of wettability alteration on fine migration behavior. The underlying mechanisms were further interpreted through interfacial thermodynamic analysis. Two potential field application schemes are proposed to facilitate practical implementation in oilfield operations. The results indicate that the water contact angle of formation particles increased from 0° to 150° when treated with 0.8 wt% HDA for 24 h. Surface characterization confirms that HDA molecules were physically adsorbed onto the particle surfaces. Displacement experiments demonstrate that the permeability reduction rate decreases significantly with increasing particle hydrophobicity. Thermodynamic analysis suggests that the work of adhesion on the modified particle surface was reduced by 93.3%, thereby weakening fluid–particle interfacial coupling and suppressing fine mobilization. This study provides a wettability-based approach for mitigating permeability damage caused by fine migration in unconsolidated sandstone reservoirs. Full article

Bangia fuscopurpurea is a marine alga with significant commercial value. Although a high-light adapted species, the productivity of its commercial cultivation is frequently limited by environmental light attenuation, resulting in the algae operating under energy-limiting, sub-saturating conditions. This study investigated its physiological responses and antioxidant defense mechanisms across a sub-saturating light gradient (20, 40, and 80 µmol photons m⁻² s⁻¹). We employed exogenous ascorbic acid (AsA) supplementation to evaluate the dynamic response of the ascorbate-glutathione (AsA-GSH) cycle. Without AsA supplementation, the 40 µmol photons m⁻² s⁻¹ condition supported redox homeostasis and the highest soluble protein accumulation. In contrast, the lowest irradiance (20 µmol photons m⁻² s⁻¹) restricted physiological performance. At 80 µmol photons m⁻² s⁻¹, which remained below the light saturation point, the algae experienced oxidative stress, indicated by elevated lipid peroxidation and hydrogen peroxide levels. The efficacy of exogenous AsA depended on these energy states. Under the highest tested irradiance (80 µmol photons m⁻² s⁻¹), AsA reduced malondialdehyde (MDA) and maintained electron transport capacity, but these effects were accompanied by a significant degradation of photosynthetic pigments. These findings imply an altered partitioning of cellular reducing power, where the demand for AsA regeneration might limit the resources available for biosynthetic pathways. The study highlights that antioxidant efficacy is constrained by the cellular energy availability, which limits simultaneous stress mitigation and growth in light-limited aquaculture environments. Full article

Shale gas exploration in the Shixi block, Guizhou, faces significant challenges due to complex geological structures and normal pressure. To reduce exploration risk, we propose an integrated “Four-in-One” evaluation workflow that combines geological sweet spots, engineering feasibility, preservation conditions, and paleogeomorphology. The workflow features a ‘cap-constraint’ velocity model to reduce structural uncertainty and a tiered multi-scale discontinuity detection strategy for low-SNR seismic data. Application of this workflow in the Shixi block delineated two Class I favorable zones (42.61 km²) with estimated resources of 8.33 billion cubic meters. Drilling results from 56 horizontal wells validate the accuracy of our prediction model, confirming that preservation condition is the primary controlling factor for gas accumulation in this normally pressured setting. This study provides a practical reference for shale gas assessment in structurally complex, normally pressured regions. Full article

Background and Objectives: Halitosis can impair psychosocial well-being, and orthodontic appliances may modify plaque retention and oral ecology. We compared patient-perceived halitosis burden, clinician-rated malodor, and oral health-related quality of life (OHRQoL) among clear aligner users, fixed-brace patients, and untreated controls, and explored oral and salivary correlates of worse malodor severity. Methods: This cross-sectional study (March 2024–November 2025) enrolled 184 participants aged 15–35 years (aligners n = 62; fixed braces n = 64; controls n = 58). Outcomes were HALT (0–100), organoleptic score (0–5), and OHIP-14 (0–56). Plaque index, gingival inflammation, tongue coating, and unstimulated salivary flow were recorded; low flow was defined as <0.25 mL/min. Organoleptic score ≥ 2 was used descriptively for clinically relevant malodor prevalence, whereas organoleptic score ≥3 defined a moderate-to-severe malodor phenotype for secondary exploratory internal modeling. Multivariable robust linear models (HALT) and proportional-odds ordinal logistic regression (organoleptic severity) were used. Results: Fixed braces showed higher HALT (53.7 ± 6.2) than controls (46.3 ± 6.4) and aligners (41.7 ± 7.4) (p < 0.001), higher organoleptic scores (2.9 ± 0.4 vs. 2.4 ± 0.6 vs. 2.2 ± 0.6; p < 0.001), and worse OHIP-14 (18.6 ± 4.7 vs. 15.9 ± 4.3 vs. 13.8 ± 4.8; p < 0.001). Clinically relevant malodor prevalence (organoleptic ≥ 2) was 96.9% in fixed braces, 79.3% in controls, and 66.1% in aligners (p < 0.001); because ≥2 was used as a broad descriptive threshold, these values should be interpreted as descriptive rather than diagnostic prevalence estimates. In adjusted models, greater tongue coating, higher plaque, and low salivary flow were associated with worse organoleptic severity, whereas appliance category did not remain independently associated with HALT once concurrent clinical correlates were included. Conclusions: Fixed braces showed higher unadjusted malodor burden and worse OHRQoL than aligners and untreated controls, but appliance category should be interpreted as a contextual exposure linked to plaque-retentive conditions rather than as a standalone causal determinant. Plaque accumulation, tongue coating, and lower salivary flow showed the strongest associations with worse malodor severity. These findings should be interpreted in light of the cross-sectional design, possible observer and selection bias, and residual confounding. Full article