Search Results (4,402)

The Variable Cycle Engine (VCE) is a key enabling technology for addressing the economic and environmental challenges of next-generation supersonic civil aircraft. This paper presents a multidisciplinary design analysis and optimization (MDAO) approach to quantitatively assess the potential benefits of Variable Cycle Engines (VCE) in the conceptual design of supersonic civil aircraft. In this approach, component-level models of a conventional Mixed-Flow Turbofan (MFTF) and a double-bypass VCE with a Core Driven Fan Stage (CDFS) are integrated into the MDAO process. Employing a multi-point optimization strategy, the engine design parameters and off-design control schedules are first determined. Subsequently, for each given engine design (MFTF and CDFS VCE), the airframe geometry parameters are optimized to minimize the aircraft Maximum Take-off Weight (MTOW). The application of this approach is illustrated through a case study of a medium-sized supersonic civil transport. The results indicate that, under the assumption of identical weights for the VCE and the MFTF, the design with the VCE reduces the MTOW by 2.8%, block fuel consumption by 5.7%, and total mission Nitrogen Oxides (NOx) emissions by 24.2% compared to the design with the MFTF. Additionally, lateral noise and flyover noise during the take-off phase are decreased by 2.2 EPNdB and 1.9 EPNdB, respectively. To account for the potential weight increase caused by the structural complexity of the VCE, a parametric weight sensitivity analysis is conducted. Results show that the VCE retains its advantages in MTOW, fuel efficiency, noise, and emissions for weight penalty factors up to 1.15. Full article

Glioblastoma (GBM) is characterized by hypoxia-driven metabolic adaptation and profound therapeutic resistance. Ferroptosis, an iron-dependent lipid peroxidation-related cell death process, has emerged as a potential vulnerability; however, its relationship with hypoxia signaling remains incompletely defined. In this study, we performed integrative transcriptomic and single-cell RNA sequencing analyses to investigate the relationship between hypoxia signaling and ferroptosis-related gene signatures in GBM. Intersection analysis of hypoxia-associated differentially expressed genes and curated ferroptosis-related gene sets identified 29 core candidate genes. FerroScore stratification revealed that tumors with higher ferroptosis-related transcriptional signatures were significantly associated with poor overall survival. Among these genes, HILPDA emerged as a hypoxia-associated gene consistently linked to ferroptosis-related gene expression patterns and immune-related transcriptional programs. HILPDA expression showed significant correlations with iron-ROS axis components, including HMOX1, NOX4, and STEAP3, and was associated with immune microenvironment changes characterized by T cell depletion and inflammatory infiltration. Single-cell RNA-seq analysis further supported the cellular-level association between HILPDA expression and hypoxia-related transcriptional states. Structural equation modeling suggested that the relationship between HILPDA expression and ferroptosis-related gene signatures may be mediated through hypoxia-related pathways. Collectively, these findings indicate a transcriptomic association between hypoxia signaling and ferroptosis-related gene signatures in GBM and identify HILPDA as a candidate gene associated with this axis. Full article

Cooking-related emissions represent a major contributor to indoor air pollution in residential kitchens, producing complex mixtures of volatile organic compounds (VOCs), odor-causing gases, oil vapors, particulate matter (PM_2.5), and combustion-related pollutants (CO and NO_x). In this study, a controlled ozone-assisted oxidation approach was integrated into a recirculating (ductless) domestic kitchen hood equipped with a confined reaction chamber and experimentally evaluated under closed-loop operating conditions where treated air was returned to the indoor environment after post-treatment. A multivariate Response Surface Methodology (RSM) framework based on the Box–Behnken design was employed to quantify and optimize the coupled effects of temperature (20–30 °C), relative humidity (40–60%), ozone dosage (1–3 ppm within the confined reaction zone), and airflow rate (150–250 m³/h) on multi-pollutant removal performance. The results demonstrate that ozone assistance substantially improves the abatement of oxidation-sensitive pollutants, particularly VOCs and odor, while airflow rate strongly governs transport-dominated pollutants such as PM_2.5 and oil vapors. In contrast, CO and NO_x exhibited limited improvement, indicating that ozone-assisted oxidation alone is insufficient for comprehensive control of combustion-related gases under short-residence-time recirculating hood conditions. The main contribution of this work is the implementation of a demand-driven ozone management strategy, supported by dual ozone sensing for reaction-zone control and outlet safety verification, where ozone generation is activated only in the presence of reactive gaseous pollutants and automatically reduced or terminated once pollutant concentrations fall below predefined thresholds, minimizing unnecessary oxidant release. Residual ozone downstream of the reaction stage was continuously monitored to prevent excess ozone return to the occupied zone. Overall, the proposed closed-loop, feedback-controlled ozone-assisted recirculating range hood concept demonstrated device-level reductions in measured VOC/odor signals under controlled conditions, while also highlighting the need for complementary post-treatment components for particle- and combustion-related pollutants. However, the potential formation of secondary oxidation byproducts was not characterized in this study, and therefore the results should be interpreted with respect to device-level pollutant removal rather than comprehensive indoor air quality improvement. Full article

Ground-level ozone (GLO₃) poses a critical threat to public health and the success of the Saudi Green Initiative, yet its long-term spatiotemporal evolution across the Arabian Peninsula remains poorly constrained. Utilizing CAMS-derived mixing ratios (1000–850 hPa) from 2003 to 2024, this study identifies a major systemic regime shift occurring in 2016–2017, marking a transition toward a more O₃-enriched atmospheric state across Saudi Arabia. While the early study period was characterized by pronounced spatial heterogeneity, post-2017 diagnostics reveal a synchronized intensification of GLO₃, particularly within the urban industrial belts of the Eastern and Western Provinces. Statistical trend metrics, including Mann–Kendall and regime-shift detection, show a persistent upward trend in GLO₃ concentrations, most significantly during winter and over the southwestern highlands. These trends are robustly coupled with increasing boundary-layer height, temperature, and UV-B radiation, alongside shifting precursor stoichiometry (CO, VOCs, NO_x) that separates titration-dominated from production-dominated regimes. Our results suggest that this mid-decade intensification reflects a convergence of anthropogenic forcing under Saudi Vision 2030 and shifting regional climatic drivers. By uncovering the transition from localized variability to kingdom-wide synchronization, this research provides a process-based foundation for targeted air quality management and the safeguarding of regional sustainability frameworks. Full article

Tumor oxygenation is a key determinant of cancer biology and treatment response, correlating with angiogenesis, recurrence, and malignant progression. Hypoxia is a defining feature of glioblastoma (GBM) and adult diffuse gliomas, generating low-oxygen niches that promote invasion, stem-like states, immune suppression, and resistance to radiotherapy and temozolomide, contributing to poor outcomes. Measuring tissue partial pressure of oxygen (pO₂) and mapping its spatial heterogeneity can, therefore, inform mechanistic understanding and therapeutic development, including hypoxia-activated prodrugs, hypoxia-responsive gene therapy, and optimized radiotherapy planning. Although direct pO₂ assessment is challenging, invasive probes and multimodal imaging can characterize regional hypoxia pre-operatively, support patient stratification, monitor treatment effects, and improve outcome prediction. This review summarizes oxygen dynamics in GBM; analyzes causes of hypoxia (rapid growth outpacing supply, diffusion-limited hypoxia, and abnormal/chaotic vasculature); compares methods to quantify oxygenation from direct measurements to noninvasive imaging surrogates; and evaluates preclinical and clinical strategies that target hypoxia to enhance standard therapy, including barriers to translation. We further integrate oxygenation with cell signaling and redox biology: oxygen gradients are transduced via hypoxia-inducible factor programs and redox-sensitive pathways (NRF2/KEAP1, NOX-derived ROS, nitric oxide/S-nitrosylation, and sulfur metabolic routes), shaping mesenchymal-like transitions and cell-death programs such as ferroptosis. Framing oxygenation as both a microenvironmental and redox-signaling variable positions oxygen imaging as an entry point to biomarker-guided therapies that exploit oxidative vulnerabilities. Full article

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