Search Results (2,859)

The accumulation of microplastics in aquatic ecosystems poses a significant threat to fish physiology and welfare. This study investigated the impact of exposure to virgin polystyrene microplastics (15 µm) on energy balance and welfare in goldfish (Carassius auratus). Fish were exposed for 14 days, and the effects were assessed through an integrated analysis of behavioral, metabolic, neuroendocrine, and physiological parameters. Microplastic exposure significantly reduces feed intake and feed anticipatory activity, indicating a potent anorexigenic effect. This effect was driven by neuroendocrine disruption, characterized by the downregulation of orexigenic neuropeptides (npy, agrp, hcrt) and the upregulation of anorexigenic signaling (pomca, cartpt, lepa). Simultaneously, exposed fish exhibited increased oxygen consumption, suggesting elevated metabolic demands. These factors converged to impaired growth and reduced hepatosomatic index, suggesting altered energy allocation. Furthermore, microplastic exposure induced anxiety-like responses and increased plasma cortisol levels, confirming the activation of the physiological stress response. Overall, these findings demonstrate that microplastics disrupt energy homeostasis and trigger behavioral shifts that ultimately compromise fish welfare and the biological resilience of aquatic species. Full article

The ATP-dependent inhibition of cytochrome c oxidase (CytOx, complex IV of the electron transport chain) is the second mechanism of respiratory control adjusting mitochondrial respiration in order to prevent excessive electron flow and reactive oxygen species (ROS) production. Here, we investigate how tricarboxylic acid (TCA) cycle metabolites and the subsequent complex I or complex II activities influence this regulatory mechanism. Therefore, CytOx activity was assessed by the oxygen consumption rate after cytochrome c (Cyt c) titration to stimulate complex IV activity in isolated rat heart mitochondria (RHM) and permeabilized AC16 cells. Mitochondrial membrane potential (Δψm) and ROS formation were analysed by flow cytometry. Our results show that TCA cycle intermediates differed in their impact on CytOx activity and subsequent ROS formation. NADH-linked substrates such as α-ketoglutarate, glutamate and malate increased respiratory capacity, but preserved ATP-dependent control of CytOx, indicating that elevated electron supply alone does not necessarily abolish ATP sensitivity. In contrast, succinate, which feeds electrons directly into complex II, strongly increased respiration causing the loss of ATP-dependent respiratory control in both model systems. Despite this strong respiratory effect, succinate induced only modest changes in mitochondrial membrane potential in isolated mitochondria, whereas permeabilized cardiomyocytes exhibited reduced polarization accompanied by increased superoxide formation. Together, these findings demonstrate that the effectiveness of ATP-dependent CytOx inhibition is influenced by TCA cycle activity and depends on the site of electron entry into the respiratory chain. Thus, substrate-dependent modulation of respiratory control links metabolite availability to mitochondrial redox regulation in cardiac cells. Full article

Mitochondrial dysfunction is a hallmark of aging and age-related physical decline in people living with HIV (PLWH) who experience accelerated aging. This pilot study investigated the relationships between platelet mitochondrial function, physical performance, and body composition in older, sedentary PLWH compared with older, sedentary HIV-negative controls. Platelets have the potential to act as minimally invasive and easily accessible biomarkers for systemic mitochondrial bioenergetics and may serve as a practical biomarker in aging-related research. We analyzed correlations between mitochondrial parameters, protein levels, and measures of physical performance and body composition in a cohort of predominantly African American men (n = 7 PLWH, n = 7 controls). Body composition was assessed using dual-energy X-ray absorptiometry (DXA), and exercise capacity through VO₂ peak and strength tests. Platelet mitochondrial bioenergetic parameters were measured by oxygen consumption rates (OCR) and extracellular acidification rates (ECAR). Key mitochondrial proteins SIRT3, COXII, DRP1, and OPA1 were evaluated by Western blotting. The PLWH and HIV-negative control groups were similar in age and cardiorespiratory fitness. In PLWH, basal OCR and ATP-linked respiration showed strong positive correlations with VO₂ peak (r = 0.874, p < 0.05 and r = 0.862, p < 0.05, respectively) and negative correlations with BMI (r = −0.856, p < 0.05 and r = −0.849, p < 0.05, respectively). SIRT3 emerged as a potential key player, demonstrating strong positive correlations with basal OCR (r = 0.804, p < 0.05), ATP-linked respiration (r = 0.787, p < 0.05), and VO₂ peak (r = 0.970, p < 0.001), and negative correlations with BMI (r = −0.830, p < 0.05) and fat mass (r = −0.827, p < 0.05) in PLWH. Analyses focused on within-group associations in PLWH because bioenergetic measures were obtained using different Seahorse platforms in PLWH and controls, precluding valid direct quantitative comparisons between groups. Our findings provide evidence for significant associations between platelet mitochondrial bioenergetics, specific mitochondrial proteins (particularly SIRT3), and key physical attributes in older, sedentary PLWH. These preliminary findings suggest that platelets may serve as minimally invasive biomarkers of systemic mitochondrial health, contribute to our understanding of mitochondrial function in HIV-associated accelerated aging, and inform future interventions to enhance mitochondrial function and improve health outcomes in this vulnerable population. However, results should be interpreted cautiously given the small sample size and exploratory design and should be considered hypothesis-generating rather than definitive. Larger, demographically more diverse studies that include HIV-negative controls are needed to validate these associations and determine their clinical relevance. Full article

Textile wastewater contains recalcitrant dyes and organic matter, requiring efficient, scalable treatment technologies. This study optimized an aluminum-based electrocoagulation (EC) process to maximize color removal (Y₁) and chemical oxygen demand (COD) reduction (Y₂) using synthetic textile wastewater (SWW), and evaluated the practical transferability of the optimized conditions using real textile wastewater (RTW). A rotatable central composite design (CCD) coupled with response surface methodology (RSM) was used to assess the effects of treatment time, NaCl concentration, and applied voltage on both responses. From a modeling perspective, the results reveal the coexistence of symmetric and asymmetric response behaviors; quadratic effects define locally symmetric regions around the optimum, while interaction terms introduce asymmetry due to coupled electrochemical phenomena. Under the optimized conditions (16.5 min, 2.9 g·L⁻¹ NaCl, 18 V), removal efficiencies reached 99% for color and 97% for COD reduction, with a specific energy consumption of 6.6 kWh·m⁻³ and sludge moisture content of 92–94%. To assess applicability beyond bench scale, the optimized voltage, current, and electrolyte concentration were applied to a 50 L batch of RTW collected from the final rinsing stage of a denim dyeing process. Treatment time was extended to 84 min to compensate for the lower current density at the larger scale; under these conditions, 95% color removal and 80% COD reduction were achieved. Full article

Growing municipal solid wastes, environmental deterioration, and the world’s increasing energy demand highlight the urgent need for effective, sustainable energy recovery solutions. Uncontrolled municipal solid wastes contribute explicitly to the global crises of climate change, pollution, and biodiversity loss. Food and organic waste are converted into value-added products using biochemical and thermochemical techniques. Anaerobic digestion (AD) is a versatile, multi-phase waste-to-energy technology that transforms organic waste into renewable energy in an oxygen-free environment. AD uses microorganisms to break down waste, yielding biogas (mostly methane and carbon dioxide) and digestate, a nutrient-fortified by-product. Compared with traditional Single-Stage Anaerobic Digesters (SSAD), Two-Stage Anaerobic Digesters (TSAD) offer notable benefits by separating hydrolysis–acidogenesis from acetogenesis–methanogenesis. These include increased methane yield, improved process control, increased microbial stability, and resistance to inhibitory substances. According to the literature, TSAD systems have been shown to increase methane yield by about 10–30% compared to SSAD. This article covers the dynamics of the microbial population at various stages, the impact of operational factors (HRT, OLR, pH, and temperature), and novel reactor designs with modular and multi-state functions. In line with Oman’s Vision 2040, this study discusses the continuous operation of a two-phase AD co-digestion process and the in-depth techno-economic feasibility of decentralized waste management through optimized biogas production. Optimizing the carbon-to-nitrogen (C/N) ratio within the range of 20–30 in co-digestion systems significantly enhances microbial activity and methane production. The potential of recent developments, such as microbial immobilization, biogas generation techniques, and hybrid integration with photobioreactors or electrochemical systems, to enhance the scalability and efficiency of bioconversion is addressed in a TSAD system. In addition to encouraging circular economy principles through efficient organic waste valorization, this review identifies TSAD as a promising approach to achieving the SDGs related to sustainable cities, clean energy, and responsible consumption. Full article

Given the increasing demand for low-phosphorus molten iron in high-value-added steel production and the rising phosphorus content in raw materials caused by the use of high-phosphorus ores in blast furnaces, the traditional converter single-slag process faces challenges such as high dephosphorization pressure, high slag consumption, and unstable endpoint control. This study systematically investigates the process principles and key influencing factors of the converter double-slag method (MURC process) as an efficient pretreatment technology for molten iron. Through thermodynamic analysis combined with industrial tests, the core process parameters affecting dephosphorization efficiency were identified, including temperature, slag basicity (R), iron oxide (T.Fe) content, and bottom-blowing stirring intensity. The results show that the optimal temperature during the dephosphorization stage is 1350–1400 °C, with slag alkalinity controlled at 1.6–2.0 and T.Fe content maintained at 19–23%. During the decarburization stage, the optimal temperature is 1620–1640 °C, and the final slag alkalinity should be increased to above 3.5. After applying the optimized “low-high-low” oxygen supply pattern and enhanced bottom-blowing stirring (0.04–0.20 Nm³/(t·min)), significant improvements were achieved in industrial practice on 180-t and 60-t converters. Lime consumption was reduced by more than 30%, the average endpoint phosphorus content decreased by approximately 0.005%, the phosphorus removal rate remained stable at above 90%, and the oxygen content in molten steel at the endpoint decreased by 50–100 ppm. This study provides a systematic theoretical basis and practical guidance for efficient and stable dephosphorization using the converter double-slag process. Full article

Physicochemical and microbiological parameters are important indicators of drinking water quality. This study assessed the quality of groundwater used for drinking in four regions of Kosovo at 16 locations using an integrated assessment framework that combined physicochemical, microbiological, and Water Quality Index (WQI) approaches. The results reveal substantial spatial variability in water quality. While most physicochemical parameters remained within recommended limits, elevated values of total dissolved solids (up to 2792.5 mg/L), electrical conductivity (up to 2768.5 µS/cm), nitrate (up to 60.75 mg/L), and phosphate (up to 0.875 mg/L) were observed at several locations, indicating localized hydrogeochemical and anthropogenic influences. Dissolved oxygen levels were generally low (0.68–5.49 mg/L), reflecting limited aeration conditions in groundwater systems. Microbiological analysis revealed critical contamination, with Escherichia coli concentrations up to 299.9 CFU/100 mL, and all sampling sites exceeded permissible limits, indicating widespread fecal pollution and rendering the groundwater unsafe for direct consumption. WQI assessment further confirmed this condition, where 93.75% of locations were classified as medium quality using the NSF-WQI method, whereas the WA-WQI method categorized 68.75% of samples as poor and 6.25% as very poor. The novelty of this study lies in the integrated evaluation of hydrogeochemical processes and microbiological contamination using dual WQI methods and multivariate statistical analysis, providing a comprehensive understanding of groundwater degradation pathways. The findings are significant for policymakers, environmental managers, and public health authorities, highlighting the urgent need for groundwater treatment, improved sanitation infrastructure, and sustainable water resource management strategies in vulnerable regions. Full article

Marine heatwaves and invasive tunicate fouling increasingly co-occur in mussel aquaculture, yet their combined effects on rope-level performance and plankton dynamics remain unclear. A 9-day field-based mesocosm experiment in Georgetown Harbour (Prince Edward Island, Canada) examined the independent and interactive effects of heatwaves (~4.5 °C above ambient) and tunicates on 50 cm sections of Mytilus edulis culture rope. Oxygen consumption rate (OCR), clearance rate (CR), capture efficiency (CE), absorption efficiency (AE), scope for growth (SFG), and condition index (CI) were quantified to assess rope-level performance, and net primary productivity (NPP) was examined to evaluate ecosystem-level effects. OCR increased with rope biomass and exhibited a biomass-temperature interaction, with a stronger increase observed under heatwave conditions. CR also increased with biomass and decreased with temperature. These shifts in metabolism and feeding resulted in near-zero SFG and reduced CI under heatwave conditions, independent of biomass. Both grazer biomass and temperature significantly influenced NPP under high-light conditions, with increasing biomass reducing NPP. Tunicate presence enhanced the retention of smaller particles, highlighting species-specific differences in particle retention within the mussel rope community. The findings suggest that warming can reduce the performance of mussel rope communities, while fouling-associated shifts in community composition may amplify grazing pressure and alter particle removal dynamics, with potential consequences for ecosystem functioning. Full article

Biological differences between sexes—particularly due to fluctuating levels of 17β-estradiol and menstrual cycle dynamics—may influence exercise-induced reactive oxygen species (ROS) formation, inflammation and exercise performance. Despite these considerations, there is a lack of research exploring how estradiol and menstrual cycle phases may impact exercise performance, exercise-induced ROS formation and inflammation. This study aimed to examine whether estradiol concentration or menstrual cycle phase may be significantly associated with resistance circuit high-intensity interval training (HIIT) performance, as well as exercise-induced formation of ROS and Interleukin-6 (IL-6). A total of 30 young healthy female participants completed a single bout of resistance-based HIIT in a fasted state. Blood samples were collected at four time points: at baseline after overnight fasting, two hours after consumption of 0.5 L of water (pre-HIIT), immediately post exercise (post-HIIT) and after 15 min of recovery (15-post-HIIT). Additionally, participants attended six fasting baseline assessments scheduled across various menstrual cycle days. These sessions enabled the assessment of estradiol, ROS and IL-6 concentrations throughout the menstrual cycle without being confounded by nutritional factors. Neither baseline levels of ROS nor IL-6 differed significantly between menstrual cycle phases (luteal vs. follicular ROS: 0.013 µmol/min, p = 0.716; IL-6: 0.052, p = 0.679) menstruation status (yes vs. no ROS: −0.056 µmol/min, p = 0.259; IL-6: −0.302 pg/mL, p = 0.088) or 17β-estradiol concentrations (low (11–≤72.5 pg/mL) vs. high (>72.5–394 pg/mL) ROS: −0.038 µmol/min, p = 0.266; IL-6: +0.015 pg/mL, p = 0.906). On the resistance-circuit-HIIT intervention day, no significant differences in ROS or IL-6 were observed between estradiol concentrations (ROS: p = 0.477; IL-6: p = 0.249), menstrual cycle phase (ROS; p = 0.752; IL-6: p = 0.557) or menstruation status (ROS: p = 0.383; IL-6: p = 0.808) from baseline to pre-HIIT, post-HIIT or 15-post-HIIT. These findings should be interpreted with caution, as the menstrual cycle phases were assigned using a calendar-based approach without biochemical ovulation confirmation and the subgroup sizes were relatively small. These findings suggest that natural 17-beta-Estradiol fluctuations within the menstrual cycle, as well as differences in the menstrual cycle itself, may not substantially modulate ROS or IL-6 responses to acute resistance-based HIIT in young healthy female adults. Full article

In 1988, two seminal studies were published almost simultaneously in the same scientific journal. Both spurred the field of brain energy metabolism research in new directions, culminating in a long-lasting debate that appeared to split its practitioners into two factions that seem unwilling to agree on what metabolic processes are fueling the active brain with adenosine triphosphate (ATP). The first study used rat hippocampal slices to demonstrate the ability of lactate to support neuronal function as the sole oxidative mitochondrial substrate. The second study demonstrated that upon brain stimulation, glucose consumption is not accompanied by respective oxygen consumption, but a non-oxidative glucose utilization or what has become known as “aerobic glycolysis”. Consequently, for almost four decades, researchers in this field have been divided between those who profess that brain activity is supported by oxidative lactate metabolism and those who insist that non-oxidative glucose metabolism supports it. Hypotheses for both concepts were offered, “The Astrocyte Neuron Lactate Shuttle Hypothesis” and “The Efficiency Tradeoff Hypothesis,” respectively. To bridge the gap between the two groups, a recent editorial, authored by over twenty leading investigators, was published. The editorial received two separate responses from investigators who supported the non-oxidative glucose consumption as the main process supporting neural activity, signaling that the gap between the two groups remained. The present perspective highlights the principal disagreements that divide this utmost important field of research. It argues that the main reason for these disagreements is rooted in the assumption that pyruvate is the end-product of aerobic glycolysis, even when many among those who adhere to this assumption accept that in the active brain glycolysis is the main provider of the necessary ATP and the end-product is lactate under aerobic conditions. The consideration of a paradigm shift, according to which lactate is the real end-product of glycolysis, independent of the presence or absence of oxygen, could bridge the great divide between those who separate glycolysis into two outcomes and those who profess that there is only one, prefix-less glycolytic pathway that always ends with the production of lactate. Full article

Acute mountain sickness (AMS) arises from hypobaric hypoxia at high altitude and still lacks effective pharmacological treatments. Although hypoxic preconditioning via gradual ascent prevents AMS, the underlying molecular adaptations have not yielded therapeutics. Here, inspired by metabolic reprogramming during stepwise altitude adaptation, we screened for anti-hypoxia compounds and identified H0802 (N-(pyridin-2-yl) pyridine-2-carbothioamide) as the most promising candidate. H0802 markedly enhances hypoxic tolerance in mice, prolongs survival under acute hypoxia, improves survival during simulated high-altitude exposure, and attenuates hypoxia-induced lung injury, accompanied by combined anti-inflammatory and antioxidant effects. Transcriptomic profiling shows that H0802 elicits a gene expression signature resembling hypoxia, including key hypoxia-related genes (Edn1, Angptl4, Mt1, Gdf15, Slc7a5, and Hif-3α) involved in glucose and oxygen metabolism. Mechanistically, H0802 stabilizes endogenous hypoxia-inducible factor (HIF) proteins under normoxia by preventing ubiquitin-dependent degradation, thereby activating hypoxia-responsive genes. In vivo, H0802 pretreatment lowers circulating glucose and hepatic glycogen while increasing brain glucose uptake, suggesting a metabolic shift that preserves cerebral energy during acute hypoxic stress; it also modulates whole-body oxygen consumption. H0802 represents a candidate for anti-AMS therapy, and phenotypic optimization of H0802 provides a potential route for drug discovery. Full article

This study explored the physiological responses and gene expression profiles of the Manila clam (Ruditapes philippinarum) and the hard clam (Mercenaria mercenaria) under heat and hyposaline stress. Experimental conditions involved increasing the temperature from 25 °C to 35 °C and decreasing salinity from 25 ppt to 15 ppt over a 6 h acclimation period, followed by 72 h exposure. Key physiological and immune indicators, including filtration rate, oxygen consumption rate, ammonia excretion rate, and the expression of related genes, were measured. Under heat stress, R. philippinarum exhibited higher filtration, oxygen consumption, and ammonia excretion rates than M. mercenaria at most sampling time points. The expression of fatty acid desaturase (Δ6FAD) and heat shock protein (HSP70) genes increased and then decreased for both species, whereas superoxide dismutase (Cu/Zn SOD) gene expression gradually decreased over time. Furthermore, the expression levels of all three genes were generally significantly higher in M. mercenaria compared to R. philippinarum. Under hyposaline stress, R. philippinarum exhibited significantly higher filtration, oxygen consumption, and ammonia excretion rates than M. mercenaria between 24 h and 72 h. Expression levels of the Na⁺-K⁺-ATPase (NKAα), HSP70, and Cu/Zn SOD genes remained higher in M. mercenaria compared to R. philippinarum. Overall, the present study indicates that M. mercenaria maintains relative stability and R. philippinarum exhibits greater physiological fluctuation under both heat and hyposaline stress. This study highlights bivalve species-specific responses to environmental stressors and provides valuable insights for aquaculture planning and ecological management in different environmental regions, particularly in the context of global climate change. Full article

Water scarcity and pollution from anthropogenic activities are major challenges, increasing the need for sustainable wastewater treatment solutions. Constructed wetlands mimic natural wetland ecosystems using macrophytes and substrates, representing a possible nature-based solution aligned with circular economy principles and the United Nations Sustainable Development Goals. So, this revision integrates recent literature, providing an overview of natural wetlands and examining the design and operation of constructed wetland systems. Also, incorporates a case study that focuses on a constructed wetland implemented at an eco-friendly dog shelter in Portugal—a unique example globally—demonstrating practical wastewater treatment and small-scale water reuse, and offering insights for sustainable management. Performance assessment based on previous work indicates that the system effectively reduces most water quality parameters to levels compliant with national and European irrigation standards. Removal efficiencies exceeded 97% for chemical oxygen demand, total suspended solids, and turbidity, while maintaining low energy consumption and minimal maintenance. Overall, constructed wetlands emerge as a sustainable alternative to conventional wastewater treatment systems; however, several challenges remain to be addressed. Future research should focus on improved aeration strategies, optimized substrate–macrophyte combinations, and long-term monitoring under climate variability, with floating wetlands offering promising opportunities to further enhance treatment efficiency. Full article

This study evaluates the technical feasibility of deploying containerized oxy-combustion power modules with integrated CO₂ capture in remote Ecuadorian Amazon oil fields. Associated petroleum gas is conditioned with a 35 wt.% diethanolamine (DEA) sweetening stage specifically implemented to remove H₂S and reduce acid-gas loading prior to combustion, improving fuel quality and protecting downstream equipment while increasing methane mole fraction for combustion. System efficiency is governed by stoichiometric oxygen demand, with methane requiring 2 mol O₂/mol fuel and hexane requiring 11 mol O₂/mol fuel; favoring methane-rich streams reduces ASU energy demand, enhances combustion performance, and lowers separation costs. The combined oxy-combustion cycle attains a thermal efficiency of 33.10% and an exergetic efficiency of 39.98%. Major energy penalties arise from the cryogenic air separation unit and the CCS train, yet operational tuning of CO₂ recirculation and steam flow could raise thermal efficiency by up to 2%. The ASU produces oxygen at 96.67% purity with an energy consumption of 0.385 kWh/kg O₂, while the CCS achieves 99.99% CO₂ capture at 0.41 kWh/kg CO₂. Sourcing gas from three production blocks provides flexibility to accommodate supply variability. The modular 272 MW unit demonstrates viability for off-grid power supply, routine flaring reduction, and scalable acid-gas valorization in frontier oilfields. Full article

Sensitive detection of Escherichia coli O157:H7 (E. coli O157:H7) in food matrices remains an important analytical challenge. Here, a colorimetric biosensor was constructed based on a bimetal oxide nanozyme composed of Ce-Fe oxide. This biosensor achieved sensitive detection of E. coli O157:H7. The Ce-Fe oxide synthesized on the basis of deep eutectic solvents (DESs) had the advantages of low solvent consumption and short preparation time. By regulating the two key factors of metal valence and oxygen vacancy content, the peroxidase (POD) activity of the nanozyme was significantly improved. Compared with the single-metal oxide nanozyme Fe oxide, the addition of Ce increased the Fe²⁺/Fe³⁺ ratio from 0.37 to 0.49, implying a possible enhancement of electron transfer between Fe²⁺ and Fe³⁺. The detection limits (LODs) of the biosensor based on Fe oxide and that based on Ce-Fe oxide were 10² CFU/mL and 10¹ CFU/mL, respectively, comparable to existing validated methods. Moreover, these two biosensors achieved satisfactory recovery rates (91–104%) and RSDs (1.2–8.8%) in the spiked lake water, juice, and lettuce samples of E. coli O157:H7, indicating their high potential for application in spiked sample detection. In summary, the method proposed in this study for improving the POD activity of nanozymes through electron transfer in DES solutions is beneficial to the development of metal oxide nanozymes. Full article