Search Results (263)

Prescribed burning is important for reducing wildfire risk and regulating fuel loads, but its implementation in mountainous forests is strongly influenced by the coupled effects of the wind field and topography, making it difficult to control. This study focuses on Yunnan pine (Pinus yunnanensis) forests in southwestern China. A three-dimensional Fire Dynamics Simulator (FDS) combined with measured fuel characteristics was used to simulate 21 slope (0–35°) and wind speed (0–2 m s⁻¹) combinations to quantitatively analyze the fire spread, flame structure, and gaseous emission characteristics during downslope prescribed burning. The local fire spread rate (ROS), evaluated along three lateral lines (Y = 2.5, 5.0, and 7.5 m), exhibits a non-monotonic dependence on slope over the tested range, with a minimum near 30° and a modest rebound at 35°. A downslope wind of 1 m s⁻¹ promotes near-surface heating and accelerates spread, whereas a stronger wind of 2 m s⁻¹ lifts flames away from the fuel bed and suppresses combustion. Thermal field analysis reveals that peak temperature decreases with increasing slope and that a late-stage secondary heating episode occurs at 35°. CO₂ emissions are significantly positively correlated with fuel consumption, reaching a peak of 717.5 kg under a 35° slope and no-wind conditions. CO emissions, as an indicator of combustion efficiency, reach their highest value of 2.23 kg at a 35° slope and a wind speed of 1 m s⁻¹, indicating that their trend is not entirely consistent with the ROS and temperature and that there is a certain degree of decoupling. The interaction between slope and wind speed transforms fire behavior from a cooperative to a competitive mechanism, and the topography–wind field coupling provides differentiated control over the combustion intensity and completeness. This study provides a scientific basis for the safe implementation of mountain burning programs and for regional carbon emission assessments. Full article

Corneal alkali burns represent one of the most severe forms of ocular surface injury and frequently result in persistent inflammation, corneal neovascularization, stromal remodeling, and permanent visual impairment. Current therapeutic approaches incompletely control the inflammatory mechanisms that sustain pathological angiogenesis and tissue disorganization. In this study, we evaluated the effects of a transglutaminase-binding fusion protein (FP) in a rat model of alkali-induced corneal injury. Following standardized alkali burns, animals were treated topically with FP, secretory leukocyte protease inhibitor (SLPI), or Buffer. Corneal epithelial healing, opacity, and neovascularization were assessed clinically and by digital image-based quantification, while histological and immunofluorescence analyses were used to evaluate stromal organization and vascular invasion. Molecular mechanisms were investigated by RT-qPCR and Western blot analysis of key inflammatory, angiogenic, and signaling mediators. FP treatment significantly accelerated corneal re-epithelialization, reduced corneal opacity, and markedly attenuated corneal neovascularization compared to SLPI and Buffer controls. These effects were associated with coordinated downregulation of pro-inflammatory cytokines and angiogenic mediators, including TNF-α, IL-17, VEGF, and cPLA₂. Notably, FP suppressed transglutaminase 2 expression and induced early and sustained downregulation of NF-κB pathway components, identifying modulation of an upstream inflammatory pathway central to corneal angiogenesis and stromal remodeling. Collectively, these findings demonstrate that FP effectively limits inflammation-driven corneal neovascularization and tissue remodeling following alkali injury, supporting its potential as a disease-modifying therapeutic strategy for inflammatory ocular surface disorders. Full article

Purpose: Chiglitazar (Chi) is a pan-peroxisome proliferator-activated receptor (PPAR) agonist with reported anti-oxidative effects in metabolic disorders. In this study, we investigate its therapeutic effects and potential mechanisms in corneal neovascularization (CNV). Methods: Scratch-wound and tube formation assays in human umbilical vein endothelial cells (HUVECs) were performed to evaluate the effects of Chi under recombinant human vascular endothelial growth factor (VEGF) stimulation. An oxidative stress model was established in human corneal epithelial cells (HCEs), and intracellular reactive oxygen species (ROS) levels were quantified by flow cytometry. A corneal alkali burn mouse model of CNV was established. Chi was then administered and compared with vehicle, pioglitazone, or fenofibrate. Corneal epithelial healing and neovascularization were assessed. Public drug–disease–target resources were integrated with RNA-seq data and single-cell transcriptomes to prioritize Chi-associated targets and pathways, which were examined by immunofluorescence, RT-PCR, and Western blotting. Ocular safety was evaluated by comprehensive ophthalmic evaluation. Results: Chi significantly inhibited migration and tube formation in VEGF-induced HUVECs, and flow cytometry confirmed effective ROS reduction. In vivo, Chi markedly improved corneal conditions compared with the vehicle and showed efficacy comparable to or superior to selective PPAR-α/γ agonists, depending on the outcome measures. Bioinformatic analyses predicted PPAR-γ as the dominant isoform, with PPAR-α secondary and PPAR-δ appearing less prominent, collectively implicating oxidative stress and VEGF pathways. Immunofluorescence verified PPAR-γ activation, predominantly localized to the corneal epithelium. RT-PCR and Western blotting supported activation of antioxidant pathways and suppression of angiogenic signals, with Western blotting confirming PPAR-γ and PPAR-α activation, whereas PPAR-δ activation appeared less evident under the present conditions. Ocular examinations demonstrated a favorable safety profile. Conclusions: Chi primarily activates PPAR-γ and PPAR-α, producing antioxidant and anti-angiogenic benefits, supporting its potential as a multi-target PPAR therapy for CNV. Full article

Wildfires are a major natural hazard causing extensive ecological damage and endangering human survival. Previous studies on wildfires in China have mostly focused on specific regions or individual drivers, with limited systematic assessments at the long-term and national scales. The spatiotemporal patterns of wildfires and their multiple driving mechanisms under China’s diverse climatic regimes remain insufficiently understood. To bridge this gap, we combined MCD64A1 burned area data (2001–2023) with multi-source natural (meteorological, vegetation, and topographic) and anthropogenic factors, using random forest models at both the national and regional scales to examine the spatiotemporal patterns, dominant drivers, and response mechanisms of wildfires in China. The results revealed that: (1) Spatially, wildfires were concentrated in northeastern and southern China, which accounted for 86.20% of the total burned area. Temporally, northern wildfires were primarily a spring-dominated fire regime, with peak activity in March and April, whereas southern wildfires were winter-dominated, peaking in February. (2) At the national scale, elevation was the key topographic factor influencing wildfire occurrence (relative importance = 0.49), with low-elevation and gentle-slope areas being more fire-prone. At the regional scale, the driving factors exhibit spatial differentiation, forming a spatial pattern of topography-dominated and climate-dominated. (3) Partial dependence plot analysis revealed nonlinear and threshold responses. Fire probability increases rapidly when the soil moisture is below 20 mm, while extremely high land surface temperatures in arid regions suppress fire occurrence due to fuel limitations. This study enhances the understanding of spatially heterogeneous wildfire drivers in China and provides a scientific basis for region-specific wildfire prevention and management strategies. Full article

In this study, the contamination of two drinking water catchments in Australia by per- and polyfluoroalkyl substances (PFAS) was investigated. PFASs in water and sediment were found at hazardous concentrations in waterways affected by transport accidents 24 and 33 years earlier. The exact cause(s) of the PFAS pollution remains unclear due to large data gaps. Both locations experienced burning fuel tankers suppressed using PFAS foam. PFAS contamination of a Blue Mountains water supply triggered the closure of two drinking water reservoirs 3–5 km downstream of the accident site. PFAS contamination of Central Coast’s Ourimbah Creek was concentrated in two floodplain wetlands adjacent to the accident site. The Ourimbah PFAS-affected wetlands are within 500 m of a drinking water groundwater bore field and 1.2 km from a raw water offtake used as part of Central Coast’s drinking water supply. The Blue Mountains contamination has impaired the Blue Mountains World Heritage Area, with perfluorooctane sulfonate (PFOS) exceeding aquatic ecosystem protection guidelines by 100 times. The mean PFOSs in stream water near the area of the Blue Mountains road accident were 2.16 µg L⁻¹ and 213.3 µg kg⁻¹ in stream sediment. This research demonstrates how spillages of small quantities of PFASs can cause major harm due to their extreme persistence, and their levels have exceedance of environmental and health guidelines for decades, with major adverse implications for drinking water supplies and conservation areas. Full article

Combining biobutanol and oxyhydrogen in an SI engine can reduce fossil-fuel use and improve power, but oxyhydrogen increases NOx. Without sacrificing combustion stability, this work investigates lean–burn coupled with exhaust gas recirculation for a gasoline port injection + biobutanol direct injection + oxyhydrogen in-cylinder negative pressure indraft engine, across five oxyhydrogen flow levels, four exhaust gas recirculation ratios, and three excess air ratios. Results show that with lean–burn + exhaust gas recirculation, oxyhydrogen more effectively lowers the coefficient of variation of indicated mean effective pressure and increases indicated mean effective pressure, peak cylinder pressure, and peak heat release rate. With 16 L/min oxyhydrogen, the negative effects of 6–12% exhaust gas recirculation on CA 0–10 and CA 10–90 are mitigated for all excess air ratios, and the crank angle corresponding to peak pressure remains optimal under lean conditions when 6% ≤ exhaust gas recirculation ≤ 12%. Oxyhydrogen reduces CO and HC after exhaust gas recirculation, while lean–burn dominates CO reduction. Exhaust gas recirculation suppresses NO more than lean–burn. At 1.1 ≤ excess air ratios ≤ 1.2, the optimal exhaust gas recirculation is 12%, ensuring favorable in-cylinder conditions. Overall, lean–burn + exhaust gas recirculation effectively controls NO and maximizes thermal efficiency and renewable-fuel substitution. The optimal strategy is “oxyhydrogen = 16 L/min, exhaust gas recirculation = 12%, 1.1 ≤ excess air ratios ≤ 1.2”. Full article

Background/Objectives: Heterotopic ossification (HO), the aberrant formation of bone within soft tissues, arises either from rare genetic mutations or more commonly from traumatic insults. It is a major cause of morbidity not only in individuals harboring causative mutations, but also in those undergoing musculoskeletal surgery or trauma and in soldiers sustaining blast or burn injuries. Bone morphogenetic protein (BMP) signaling is a central driver of both hereditary and acquired forms of HO. Primary cilia are nonmotile, antenna-like organelles that extend from the cell surface and serve as crucial sensory and signaling hubs by concentrating key pathway components within a confined volume at the ciliary tip. However, their functional role in the pathogenesis of traumatic HO remains poorly understood. Methods: We investigate the role of primary cilia in traumatic HO using a genetically modified mouse model and cellular model. Results: We demonstrate that BMP signaling is attenuated when primary cilia function is disrupted. Both ciliation frequency and ciliary length were reduced in Scleraxis-CreERT2; Intraflagellar transport 88 ^{floxed/floxed} (Scx-CreERT2;Ift88^fl/fl) tenocytes. Deletion of Ift88 effectively suppressed pathological BMP signaling and inhibited HO formation. Conclusions: These findings establish that functional primary cilia are required for traumatic HO development and highlight ciliary regulation as a potential therapeutic avenue for preventing or mitigating post-traumatic HO. Full article

Lightning-induced breaking accidents of medium-voltage insulated conductors pose a serious threat to the safety of distribution networks, and the key cause lies in the establishment and sustained combustion of the power-frequency follow-current arc after lightning overvoltage breakdown. This paper systematically investigates the formation mechanism and critical conditions of power-frequency follow-current arcs using combined simulation and experimental approaches. Based on the streamer discharge theory, a lightning breakdown model was established and combined with the arc energy balance equation, revealing that the establishment of power-frequency follow-current arcs is essentially determined by the post-breakdown energy competition process. The simulation results show that the required anode electric field strength for lightning breakdown is not less than 3 kV/mm. When the power-frequency voltage reaches 10 kV, Joule heating of the arc continuously exceeds heat dissipation loss, enabling restrike after zero-crossing and sustaining stable burning. Experiments verified this voltage threshold and further revealed that the arc establishment rate exhibits nonlinear growth with increasing power-frequency voltage, exceeding 90% at power-frequency voltages ≥ 10 kV. The study also reveals that increased gap distance reduces the arc establishment rate, while the introduction of insulators can enhance it by approximately 20%. This study clarifies the energy criterion for power-frequency follow-current arc establishment and the influence patterns of key parameters, providing theoretical basis and engineering reference for lightning protection design and arc suppression in medium-voltage insulated lines. Full article

Major trauma induces innate immune suppression, yet the underlying mechanisms are poorly understood. Resistin is an immunosuppressive molecule that is systemically elevated post-injury. However, its role in trauma-induced immune dysfunction and clinical outcomes is poorly defined. Here, we acquired blood samples from 147 adult trauma patients (≤1, 4–12, 48–72 h post-injury) and 95 burns patients (days 1, 3, 7, 14, 28 post-burn). We measured plasma resistin concentrations, studied resistin gene expression in peripheral blood mononuclear cells (PBMCs) and neutrophils, and measured resistin production by lipopolysaccharide (LPS)-challenged whole blood leukocytes. To identify potential novel triggers of resistin secretion by immune cells, we examined the effect that stimulation with mitochondrial-derived damage-associated molecular patterns (mtDAMPs) had on resistin production by neutrophils isolated from healthy donors. We also treated neutrophils, from healthy donors, and THP-1 cells with resistin prior to stimulation with Phorbol 12-myristate-13-acetate (PMA) or LPS to study its effects on reactive oxygen species (ROS) and cytokine production, respectively. Injured patients presented with significantly elevated circulating resistin concentrations and increased resistin gene expression in PBMCs and neutrophils. LPS and mtDAMP stimulation promoted resistin secretion by whole blood leukocytes and neutrophils. Plasma resistin concentrations were negatively associated with PMA-induced ROS generation by neutrophils, and LPS-induced cytokine production by monocytes. Resistin-treated THP-1 cells and neutrophils exhibited impaired functional responses upon secondary stimulation with LPS or PMA, respectively. Trauma patients who developed multiple organ dysfunction syndrome (MODS) presented with significantly elevated resistin concentrations, which at 48–72 h post-injury showed good performance as a predictor of post-traumatic MODS (AUROC, 0.796). Hyperresistinemia is an immediate and persistent feature of the inflammatory response to injury that may contribute to the development of innate immune dysfunction. Full article

Straw burning is a major source of regional air pollution. However, its reliable remote sensing detection faces problems in distinguishing agricultural fires from non-agricultural thermal anomalies, adequately leveraging burning seasonality, and overcoming the scarcity of pixel-level annotations. To comprehensively address these issues, this study proposes an end-to-end framework for straw burning identification that integrates spatio-temporal weighting and semi-supervised learning. The framework introduces a data-driven spatial weight optimization method to automatically learn discriminative weights for diverse land cover types (e.g., farmland, industry), replacing subjective empirical settings. Furthermore, a temporal weighting model, developed using Kernel Density Estimation, dynamically adjusts classification confidence according to historical burning seasonality, enhancing recall during peak seasons while suppressing off-season false positives. Finally, an adapted Dual-Backbone Dynamic Mutual Training (DB-DMT) strategy collaboratively leverages both limited labeled (24.5%) and abundant unlabeled (75.5%) high-resolution imagery, significantly improving model generalization in label-scarce scenarios. Validation across five representative regions of China demonstrated the framework’s superior performance, achieving a semantic segmentation mean Intersection over Union (mIoU) improvement of 3.33% (to 71.92%) and increasing precision in Henan from 95.21% to 97.71%. Crucially, the framework effectively reduced the off-season false positive rate (FPR) from 5.14% to a mere 0.23% in highly industrialized regions like Tianjin. By systematically mitigating both spatial geolocation bias and seasonal phenology confusion, our approach offers a robust and scalable solution for straw burning monitoring and a transferable paradigm for other environmental remote sensing applications. Full article

The performance improvement of mechanical components often relies on heat treatment processes, but these processes inevitably result in oxidation burn-off. The repeated formation and spallation of Fe₂O₃ rich oxide scales lead to substantial iron depletion and surface deterioration. Consequently, environmentally sustainable and economically viable protective coatings are required to suppress oxidation induced burn off. In this work, a TiO₂-MgAl₂O₄ composite coating was synthesized from magnesium slag and applied to Q235 carbon steel to enhance its performance during prolonged high temperature heat treatment. Oxidation tests conducted at 900 °C for 60 min demonstrated that the coating markedly improved the oxidation resistance of carbon steel, with an enhancement of approximately 87% relative to the uncoated specimens. To elucidate the protective mechanism, SEM-EDS, XRD, TG-DSC, and XPS analyses were employed. Based on Wagner Theory, the formation of interfacial phases such as Mg_7.92Al_15.31Fe_0.66O₃₂, which effectively impeded oxygen ion diffusion and thereby enhanced the oxidation resistance during high-temperature exposure. Furthermore, the synergistic effect of aluminum-, magnesium-, and titanium-containing compounds in the coating contributed to suppressing the diffusion of oxygen and iron ions, thus further improving the protective performance. This study provides a systematic theoretical foundation and practical guidance for addressing material loss during high-temperature processing of mechanical components, as well as for promoting the resource utilization of magnesium slag. Full article

This study investigates how outlet pressure influences the fire suppression performance of a compressed air foam system (CAFS), with the aim of supporting system optimization and engineering applications. An experimental apparatus for foam performance testing is used to measure changes in foam flow rate, expansion, initial velocity, initial momentum, and drainage time at different outlet pressures. On the basis of relevant theoretical models, the factors causing discrepancies between model predictions and experimental results are examined, and the models are then refined. How the outlet pressure of CAFS affects foam performance is thereby clarified. The results show that foam flow rate increases as outlet pressure increases. At higher pressures, shear-thinning and intensified gas–liquid mixing affect the foam. As a result, the growth of flow rate in the range of 0.01–0.03 MPa is significantly higher than that in the range of 0.06–0.10 MPa. Both initial velocity and initial momentum increase significantly with increasing pressure, whereas the expansion decreases. Within the outlet pressure range of 0.01–0.10 MPa, the initial velocity increases from 1.23 m/s to 6.65 m/s, the initial momentum rises from 4.6 kg·m/s to 34.1 kg·m/s, and the expansion decreases from 9.2 to 5.4, indicating reduced foam stability. Drainage time and drained mass vary non-monotonically with outlet pressure. The longest drainage time and the smallest drained mass occur at 0.06 MPa. Fire suppression performance improves as outlet pressure increases. A higher outlet pressure enables the foam solution to penetrate the flame zone more effectively and to cover the surface of the burning material. In addition, changes in foam properties enhance the thermal insulation and smothering effects of the foam layer, as well as its heat absorption and cooling capacity. These effects together improve the efficiency of fire source cooling. Full article

Southern Africa is highly sensitive to climate variability associated with the El Niño Southern Oscillation (ENSO), which strongly influences hydroclimate, vegetation dynamics, and atmospheric composition. This study examined the impacts of the 2015/16 El Niño on vegetation, meteorological conditions, and atmospheric emissions over Southern Africa using satellite observations and reanalysis data. Time-lagged cross-correlation analysis of seasonally adjusted time-series was applied to characterize synchronous and delayed interactions among vegetation indices, hydrological variables, meteorological drivers, and air-quality parameters. Bayesian causal impact analysis was further used to quantify El Niño-induced anomalies by comparing observed conditions with counterfactual scenarios representing the absence of the event. The results showed that vegetation greenness responds primarily to concurrent moisture availability, with strong positive associations between NDVI, precipitation, soil moisture, and canopy water. Moisture-related variables exert delayed influences on atmospheric composition, highlighting the role of wet scavenging and dilution. Carbonaceous aerosols (black carbon [BC] and organic carbon [OC]), particulate matter [PM_2.5], and aerosol optical depth exhibit strong synchronous coupling, indicating a dominant biomass-burning source. The causal impact analysis reveals statistically significant and sustained post-2015 increases in fire-related emissions (carbon monoxide [CO], BC, OC, PM_2.5, and aerosol optical depth [AOD]), particularly during austral winter and dry seasons. In contrast, precipitation, soil moisture, evapotranspiration, and vegetation greenness show persistent negative anomalies, reflecting widespread drought stress under elevated temperatures. Overall, the findings demonstrate that the 2015/16 El Niño amplified fire emissions while suppressing ecosystem functioning across Southern Africa, underscoring strong climate–fire–vegetation feedback with important air-quality and environmental implications. Full article

Background/Objectives: High-voltage, low-current electric shocks inflict superficial second-degree burns on the skin, accompanied by a vicious cycle of excessive oxidative stress and inflammation. As efficient treatment of such electrical burns remains a clinical challenge, we explored the efficacy of an injectable thermosensitive chitosan hydrogel engineered with an antioxidant agent (astaxanthin) and an anti-inflammatory agent (ibuprofen) for the treatment of high-voltage, low-current electrical burn injuries. Methods: The proposed CS/AST/IBU hydrogel was prepared and its thermosensitivity was characterized. Subsequently, the hydrogel was injected into the wounds of male Sprague–Dawley (SD) rats subjected to electrical burn injury (20 kV, 3 mA). Finally, a series of experiments were performed to elucidate the dynamics of wound healing and the mechanisms by which the hydrogel promotes wound repair. Results: The injectable hydrogel, through its thermally responsive gelation effect at 37 °C, adapts to the complex irregularities of the wound surface. This facilitates the release of astaxanthin and ibuprofen throughout the wound, which collectively diminish the formation of reactive oxygen species and MDA. Furthermore, it enhances the synthesis of endogenous antioxidants such as SOD, CAT, and GSH; encourages collagen deposition; stimulates the development of dermal appendages; and fosters neovascularization. It interrupts the deleterious cycle of oxidative stress and inflammation mediated by the NF-κB signaling pathway, thereby suppressing the expression of pro-inflammatory markers such as TNF-α, CD11b, and IL-1β while upregulating CD163, an anti-inflammatory receptor. Conclusions: The use of this multipronged, contour-adaptive hydrogel represents an effective strategy for complex wound management and demonstrates broad therapeutic potential for superficial second-degree electrical burns caused by high-voltage, low-current discharge. Full article

Wildland fire behaviour is strongly governed by the coupled effects of wind and terrain slope, yet the literature remains fragmented across experimental, empirical, mathematical, and physics-based modelling traditions. A systematic scoping review with narrative synthesis was performed (Web of Science, Scopus, and Google Scholar plus citation chaining), screening studies for explicit wind–slope treatment with reported forcings and outcomes. Across more than 150 studies, slope benches, wind tunnels, trenches/canyons, and field burns show that upslope–wind alignment promotes flame attachment and a shift from radiation-led to convection-led preheating (often near 20–30° slopes and moderate winds), whereas opposing or downslope forcing lifts flames and suppresses spread; confined geometries can trigger eruptive acceleration. Mathematical analogues and empirical models provide fast predictions using compact wind/slope modifiers and enable scenario and burn-probability mapping but typically prescribe coupling and miss regime transitions. Physics-based LES/CFD and coupled atmosphere–fire systems resolve terrain–flow feedback sand can yield reduced-order laws suitable for embedding into operational tools, albeit at higher computational cost and with validation gaps. Benchmarks are consolidated, approaches are compared using a common rubric (fidelity, validation, applicability, cost, and operational utility), and priorities are identified for cross-scale datasets, firebrand transport in complex terrain, and real-time coupled prediction. Full article