Search Results (4,398)

This study introduces a physics-informed machine learning framework for predicting transient emissions and energy variables in a retrofitted heavy-duty diesel vehicle. It merges data-driven modeling with physically derived features for reliable real-world analysis. A Random Forest regressor is trained on a public dataset (26 trips from one instrumented vehicle) to predict CO₂ and NO_x mass rates, exhaust temperature, exhaust mass flow rate, and fuel flow rate from synchronized multi-sensor inputs using past-only, time-lagged features. On held-out trips, exhaust temperature prediction achieves $R^2$ = 0.9997 and $\mathrm{RMSE}$ = 0.53 g/s; for CO₂, with $R^2$ = 0.9985 and $\mathrm{RMSE}$= 0.38 g/s, comparable performance is reported for NO_x, exhaust flow, and fuel rate. The trained model is integrated into a simulation framework to enable the evaluation of alternative operating conditions and powertrain configurations. First, the impact of cold-start versus hot-start operation is assessed, showing cumulative emission penalties of up to +28% for CO₂ and +30% for NO_x. Second, the effect of hybridization is investigated by comparing the baseline thermal configuration with a hybrid electric architecture, resulting in estimated reductions of −12.2% in CO₂ and −10.5% in NO_x emissions. This tool excels in high-fidelity emission prediction and system-level energy analysis, aiding advanced powertrain assessments under realistic driving conditions. Full article

Background: Although air pollution is increasingly considered an environmental hazard for inflammatory bowel disease (IBD), existing evidence predominantly relies on single-pollutant models that fail to capture mixed exposures, with modifying effects of individual lifestyle and residential environments remaining largely unexplored. Methods: We conducted a prospective cohort study using UK Biobank data, including 323,608 participants followed for incident IBD. Annual mean concentrations of five air pollutants [nitrogen dioxide (NO₂), nitrogen oxides (NO_x), and PM with aerodynamic diameters of ≤2.5, 2.5–10, and ≤10 μm (PM_2.5, PM_2.5–10, PM₁₀)] and greenspace percentage within 300 m and 1000 m buffers were assigned to each participant’s residential address. A healthy lifestyle score was defined by five factors: smoking status, alcohol consumption, physical activity, sleep patterns, and dietary quality. Cox proportional hazards models with quantile g-computation (QGC) were employed to examine associations between single- and mixed-air-pollutant exposures and IBD risk. Stratified analyses were performed by healthy lifestyle, lifestyle score, and greenspace percentage. Results: During the follow-up period, 1649 and 805 participants developed ulcerative colitis (UC) and Crohn’s disease (CD), respectively. Single-pollutant models suggested that exposures to most air pollutants were substantially associated with increased risk of IBD, and the association strengths were more pronounced for UC than for CD. QGC analyses indicated that the hazard ratios (HR) of IBD risk were 1.068 (95%CI: 1.018–1.121) for each one-quantile increase in the air pollutant mixture, with NO₂ weighted as the largest contributor. High physical activity was significantly linked to an attenuated UC-pollutant mixture association. Conclusions: This study found that exposure to an air pollutant mixture was associated with increased risk of IBD, especially for UC, with NO₂ contributing the largest effect size. The certain attenuated air pollution effects of healthy lifestyles and residential greenspaces underscore the need for integrated public health strategies with environmental management. Full article

The transport sector is a major contributor to urban air pollution and greenhouse gas emissions in Pakistan, posing significant challenges to sustainable development and climate commitments. This study develops the first technology-resolved, high-resolution, multi-pollutant emission inventory and scenario analysis for Pakistan’s transport sector, addressing key gaps in previous studies that lacked integrated multi-pollutant assessments, comprehensive coverage of non-road sources, and long-term scenario comparisons. The analysis integrates road and non-road transport sources within the Greenhouse Gas–Air Pollution Interactions and Synergies (GAINS) modeling framework. Emissions are projected for 2024–2050 under a business-as-usual (BAU) scenario and three mitigation pathways: an Electric Vehicle Transition (EVT) emphasizing transport electrification, a Euro-VI scenario focusing on stringent fuel and vehicle emission standards, and an integrated nationally determined contribution strategy (NDC+) scenario combining electrification, regulatory improvements, and structural transport reforms. In 2024, transport-related emissions are estimated at approximately 22 kt of fine particulate matter (PM_2.5), over 300 kt of nitrogen oxides (NO_x), and nearly 39 Mt of carbon dioxide (CO₂), alongside substantial emissions of other gaseous pollutants and short-lived climate forcers. By 2050, the NDC+ scenario achieves the largest reductions relative to business-as-usual, demonstrating that coordinated electrification and emission control strategies can simultaneously reduce air pollution and greenhouse gas emissions. The results demonstrate strong synergies between climate mitigation and air quality improvement, showing that integrated strategies combining electrification with stringent emission standards can simultaneously reduce greenhouse gas emissions and major air pollutants while advancing cleaner and more sustainable mobility. This analysis provides a consistent and policy-relevant evidence base derived from best-available data and modeling tools to support Pakistan’s NDC implementation, sustainable mobility planning, and integrated air quality and climate strategies, with lessons transferable to other rapidly developing economies. Full article

The injection of green hydrogen in the natural-gas infrastructure is an efficient option for the transport, consumption, and storage of large amounts of renewable energy, helping to overcome the balancing problems of the electricity network as well as to decarbonize the energy use in different sectors (e.g., civil, transport, industry). However, the injection of H₂ can determine relevant implications on the safety and integrity of pipelines and of the main components of the networks, as well as unwanted issues in the combustion process. In this paper, the effects of hydrogen injection in methane up to 35%vol on an industrial combustor under lean conditions have been evaluated from a theoretical and experimental point of view. In particular, the emissions of the combustion process have been investigated through experimental analysis and numerical simulation of key parameters (e.g., flame temperature, flame stability, flame speed, etc.) and the flue-gas analysis (e.g., flue-gas temperature, emissions of CO, NO_x, etc.). From the point of view of the combustion process, the obtained results show that no issues occur from the injection of hydrogen into methane up to 23%vol under lean conditions. Full article

Hydrogen is recognized as a promising energy vector for the decarbonization of energy production. Besides the undoubted benefits, its utilization poses some technological challenges in the generation, transportation, storage and utilization phases, which must be carefully assessed. The aim of this work is to assess the effect of methane substitution with hydrogen in a dual-fuel diesel/methane engine on fuel conversion efficiency and pollutant emission levels. Therefore, an extensive experimental campaign has been designed in which a hydrogen/methane mixture with variable composition is ignited with a pilot injection of diesel fuel. The engine was operated in naturally aspirated or supercharged conditions, and conventional or alternative combustion strategies were implemented, spanning a pilot injection timing over a broad range of values. The results show that the effect of a variation in H₂ percentage of up to 20% strongly depends on air intake pressure and pilot injection timing. In particular, engine efficiency and HC and CO emissions are penalized as H₂ percentage increases; however, this penalty can be mitigated in naturally aspirated conditions if a late pilot SOI strategy is adopted. In terms of NO_x, a reduction is observed as H₂ percentage increases. Late SOIs determine the lowest levels of NO_x emissions in both naturally aspirated and supercharged conditions. Full article

Cirrhosis is no longer viewed solely as an isolated hepatic disorder but rather as a complex multisystemic disease that affects cardiovascular, renal, pulmonary, metabolic, and immune systems. One of its most clinically relevant but under-recognized consequences is cardiac dysfunction, manifesting as cirrhotic cardiomyopathy, portopulmonary hypertension, right ventricular (RV) failure, and impaired myocardial strain. Oxidative stress (OS) has recently emerged as a fundamental mechanistic link between hepatic fibrogenesis and myocardial remodeling, acting through mitochondrial injury, NADPH oxidase activation, nitric oxide dysregulation, iron-mediated ferroptosis, and inflammatory cytokines. These alterations lead to diastolic dysfunction, autonomic imbalance, myocardial fibrosis, electrophysiological abnormalities (including QTc prolongation), and impaired RV–pulmonary artery coupling. Redox biomarkers such as malondialdehyde (MDA), NOX2-derived peptides, GSH/GSSG ratio, sST2, NT-proBNP, and 8-isoprostanes hold promise in detecting early subclinical cardiac involvement in cirrhosis. Novel antioxidant therapies, including mitochondrial-targeted molecules, NOX inhibitors, and ferroptosis blockers, may improve myocardial remodeling and hemodynamic stability. This review explores the central role of redox imbalance in the cardiohepatic syndrome and its potential utility in diagnosis, monitoring, and therapy. Full article

This article provides a comprehensive review of current state of knowledge regarding the ongoing development of hydrogen-fueled internal combustion engines (H₂ICE). It describes the key challenges, the resolution of which will determine further progress in the development, practical application, and popularization of H₂ICE. The article details the problems associated with creating and optimizing the fuel mixture in the H₂ICE cylinder. It also highlights directions for development of hydrogen injection, ignition, and boosting processes. The risks resulting from abnormal combustion processes and the related optimization of combustion strategies in H₂ICE are extensively discussed. Problems and difficulties associated with adapting existing engine designs to hydrogen fueling are also considered. Attention is paid to the different degradation patterns and the requirements placed on engine lubricating oil when fueling engines with hydrogen. The article then describes emissions from hydrogen-fueled engines, with particular emphasis on high NOx emissions and methods for reducing those emissions. The last part of the article discusses the influence of hydrogen admixture in various hydrocarbon fuels on combustion processes, engine performance and harmful exhaust emissions into the atmosphere. The article stands out in that it identifies and describes the most important challenges that determine the further development of H₂ICE engines. It also provides a comprehensive overview of the current state of knowledge in the field of ongoing development of hydrogen-powered internal combustion engines (H₂ICE). Full article

Background/Objectives: Nitric oxide (NO) is a key mediator of vascular, metabolic, and redox pathways, influencing exercise performance. Beetroot, a natural source of inorganic nitrate, increases NO bioavailability and may modulate oxidative stress and inflammation, though data in endurance athletes remain limited. The aim of this study was to assess the effects of a novel beetroot-based nitrate supplement (B-bNs) on NO metabolism, oxidative stress, and inflammation in non-professional triathletes. Methods: This was a randomized 2 × 2 cross-over pilot study with two 7-day periods (B-bNs vs. No treatment), separated by a 15-day washout (4 visits: Day 1, 7, 22 and 28). Samples were collected at baseline (T0), 2 h post-first dose (T1), and after 7 days (T2) for the supplementation period (B-bNs) and at T0 and T2 for the “no treatment” period. The following biomarkers from plasma and urine were evaluated: NO pathway (NO metabolites (NOx), nitrite (NO₂), inducible nitric oxide synthase (iNOS), peroxynitrite, 3-nitrotyrosine (3-NT)), oxidative stress (reactive oxygen species (ROS) production, 8-isoprostane, superoxide dismutase (SOD) activity), and cytokines (IL-6, IL-10). A total of 10 male triathletes (mean age 48.1 ± 9.8 years and BMI 23.9 ± 2.2 kg/m²) participated in this study. Results: No adverse events were reported. After 7 days of supplementation (T2 vs. T0), significant increases in NOx in plasma and urine (about +155%), iNOS (+56%), peroxynitrite (+60%), 3-NT (+8.6%), ROS (+413%) and IL-6 (+73%) were recorded. These values resulted significantly higher compared to “no treatment” (all p = 0.002), with no significant differences for 3-NT, SOD, 8-isoprostane, IL-6, and IL-10. Conclusions: Beetroot-based nitrate supplementation may enhance the NO-related pathway in non-professional endurance athletes with nitric-peroxydation activation, occurring without evidence of lipid oxidative damage. Larger placebo-controlled trials with standardized diet/training and performance outcomes are needed to determine the functional significance of these preliminary findings. This study was registered in the ISRCTN registry (ISRCTN10885376). Full article

Periodontitis represents a primary etiological factor in tooth mobility, with oxidative stress contributing critically to periodontal tissue destruction. Evodiamine (EVO), a quinazolinocarboline alkaloid, exhibits multiple biological activities; however, its antioxidant effects and mechanism in periodontitis have not been elucidated. The aim of this study was to investigate the regulatory effect of EVO on oxidative stress in periodontitis and to explore the associated molecular mechanism. The results indicate that EVO exhibits potent antimicrobial activity against key periodontal pathogens and suppresses pathogen-induced ROS generation as well as the release of pro-inflammatory cytokines (IL-1β, IL-6, TNF-α) under periodontitis conditions. EVO binds specifically to the Kelch domain of KEAP1 with a strong binding energy (−11.67 kcal/mol), inhibits KEAP1–NRF2 interaction, and consequently upregulates the expression of antioxidant enzymes (HO-1, NQO1, GCLC, and SOD2), while downregulating the expression of iNOS, COX2, and NOX2. Furthermore, EVO inhibits the pro-apoptotic effect of the JAK2/STAT3 signaling axis and mitigates inflammation, alleviates cell cycle arrest, and promotes the migration and repair of periodontal ligament cells. Collectively, these findings suggest that EVO acts as a potential binder of KEAP1 that alleviates periodontal inflammation through modulation of oxidative stress and regulation of the JAK2/STAT3 pathway. Full article

This study proposes an integrated analytical framework (IAF) as a tool to simultaneously assess vulnerable social groups within their administrative context. This study hypothesizes that analyzing vulnerable groups through socio-spatial delineation reveals subnational disparities and sub-regional heterogeneity in energy poverty (EP) indicators, associated with additional context-sensitive environmental consequences of energy use. Using Hungarian deprived rural settlements (DRSs) (n = 300) as an example, mixed methods were applied to examine national–regional disparities, intra-regional variations, and the environmental implications of extreme household energy use practices. Results show that both socio-economic indicators and building energy efficiency, and energy-use profiles, fall short of national indicator performance. The sample outlined by the IAF performed homogeneously regarding socio-economic circumstances and showed mild differences in housing quality and energy access. These results indicate not structural differences but variation in underlying regional drivers, highlighting the region-specific manifestation of EP. The energy-use-related environmental assessment was performed using a parametrized building-stock model and the two most extreme energy-use scenarios for households relying on solid fuels. The results suggest that the use of substitute fuels substantially increases the combined emissions of CO₂, CO, PM, NOx, and SOx by up to 32 percentage points. Although limitations constrain the reporting of empirically representative results, findings underscore the potential policy relevance of DRSs in national climate objectives. Full article

Acute lung injury (ALI) is characterized by excessive inflammation, oxidative stress, and impaired resolution responses, partly driven by dysregulated macrophage activation. In this study, a defined mixture of eicosapentaenoic acid (EPA)-derived dihydroxyeicosapentaenoic acids (diHEPAs), comprising 5,15-diHEPA and 8,15-diHEPA at an equimolar ratio, was generated using soybean lipoxygenase and its protective effects on lipopolysaccharide (LPS)-induced ALI were investigated. Mice were orally administered 5,15-diHEPA (40 μg/kg), 8,15-diHEPA (40 μg/kg), or the diHEPA mixture (20 μg/kg each) for 7 days before LPS challenge. LPS exposure induced severe lung injury, as evidenced by an increased lung wet/dry ratio, inflammatory cell infiltration, and oxidative stress. Treatment with diHEPAs attenuated lung pathological damage, reduced proinflammatory cytokine production, and restored redox homeostasis. Consistently, in vitro studies in RAW264.7 macrophages showed that the diHEPA mixture suppressed LPS-induced inflammatory responses through the inhibition of NF-κB signaling and rebalanced oxidative stress via modulation of the NOX2/Nrf2/HO-1/ROS axis. Altogether, these results indicate that EPA-derived diHEPAs confer protection against ALI by suppressing inflammation and restoring redox balance, emphasizing their potential as therapeutic agents for ALI. Full article

The increasing need to reduce reliance on fossil-derived aviation fuels and mitigate environmental impacts has intensified research into renewable alternatives for aviation energy systems. The growing interest in ethanol-based fuels is primarily driven by their simple oxygen-rich molecular structure and advantageous physicochemical characteristics, yet experimental studies examining their application in hybrid power architectures, including micro-turboprop engine-based power sources, are still limited. This study presents an experimental investigation of ethanol–Jet A1 fuel blends used in a micro-turboprop engine operating as a power generation unit for unmanned aerial vehicle applications. Ethanol was blended with Jet A1 at volumetric fractions of 10%, 20% and 30% and the engine was tested under multiple operating regimes corresponding to different electrical power outputs. Exhaust gas temperature, electrical power output and gaseous emissions (CO and NO_x) were measured for each operating condition. The results indicate that low ethanol fractions (E10) provide performance comparable to neat kerosene, while higher ethanol fractions lead to a reduction in exhaust gas temperature at low-power regimes due to the lower heating value and high latent heat of vaporization of ethanol. Emission measurements showed a decrease in NO_x emissions with increasing ethanol content, associated with lower combustion temperatures, while CO emissions increased at low-power regimes due to incomplete combustion under lean conditions. Additionally, combustion instability was observed during rapid transitions from maximum to idle regime operation for higher ethanol blends, attributed to transient ultra-lean mixtures, evaporative cooling, and reduced reaction rates. The results demonstrate that ethanol–kerosene blends can be used in micro-turboprop systems at low blend ratios without major performance penalties, but transient operating conditions impose stability limits that must be considered in practical UAV power system applications. Full article

Pulsed polarization of Au|YSZ gas sensors is examined to clarify the mechanism of NO_x detection under dynamic operation and to disentangle catalytic surface effects from electrochemical relaxation. Using gold electrodes with substantially lower catalytic activity than platinum explicitly enables this mechanistic separation. During pulsed polarization, periodic voltage pulses are followed by self-discharge under open-circuit conditions, and the response is measured based on the self-discharge rate. NO₂ consistently accelerates the self-discharge from the beginning, whereas NO slows the relaxation predominantly at later times. CO and H₂ produce similar delaying effects, and C₃H₆ shows no measurable influence under the tested conditions. Decreasing ambient O₂ slows the discharge and amplifies the NO₂ effect, which indicates that oxygen supply and surface exchange at the triple-phase boundary are rate determining. A Pt-containing catalytic overlayer drives local NO/NO₂ interconversion toward equilibrium so that both gases yield to an accelerated self-discharge. These findings support a mechanistic picture in which NO₂ provides effective oxygen equivalents that accelerate discharge, whereas NO, CO, and H₂ consume oxygen and slow down discharge. Overall, this establishes a materials-based approach for distinguishing between NO and NO₂ and evaluating the underlying mechanism during pulsed polarization. Full article

Aviation heavy-fuel piston engines are widely used in UAVs, general aviation, and military platforms due to their fuel efficiency and adaptability. However, emissions of NO_x, PM, and other pollutants pose significant environmental challenges. This paper reviews emission-reduction strategies, including combustion-chamber optimization, fuel-injection control, alternative fuels, and exhaust after-treatment technologies. Research indicates that optimizing combustion-chamber geometry, high-pressure common-rail injection, and turbulence enhancement improve combustion efficiency and reduce emissions. Biofuels, synthetic aviation fuels (SAF), and hydrogen-based fuels demonstrate strong potential for low-carbon emissions, while after-treatment technologies such as SCR, DPF, and EGR effectively mitigate NO_x and PM emissions. Despite technological advancements, challenges remain in balancing combustion efficiency with NO_x control and ensuring compatibility between EGR and combustion stability. Future advancements in intelligent combustion control, novel catalytic materials, low-temperature combustion, and high-efficiency after-treatment systems will drive aviation diesel engines toward lower emissions, higher efficiency, and greater intelligence, contributing to the green and sustainable transformation of aviation propulsion systems. Full article

With the growth of global maritime transportation volume and fuel shortages caused by excessive oil consumption, energy conservation and emission reduction technologies for marine diesel engines have become a core research focus. A three-dimensional (3D) CFD model of a methanol–diesel dual-fuel marine diesel engine was developed in AVL-FIRE and coupled with a CHEMKIN reaction mechanism. The model was validated against experimental data, with errors in cylinder pressure, heat release rate, and major emissions below 5%. Based on the validated model, the effects of the methanol blending ratio (0–30%), injection advance angle, intake temperature, intake pressure, and EGR rate on combustion and emissions were investigated. The results show that increasing the methanol blending ratio reduced cylinder pressure, in-cylinder temperature, and NO and soot emissions, while increasing the peak heat release rate. Advancing injection timing improved combustion and reduced CO and soot emissions but increased NO formation. Higher intake temperature worsened combustion performance and increased NO, CO, and soot emissions. Orthogonal analysis and regression-based optimization identified an optimal condition with a methanol blending ratio of 27%, an EGR of 12.5%, an injection advance angle of 21.2 °CA, an intake temperature of 319.05 K, and an intake pressure of 0.223 MPa. Under this condition, the NOx mass fraction was 1.65 × 10⁻⁵. Full article