Search Results (1,648)

This work reports the synthesis, characterization, and photocatalytic performance of multifunctional spheres based on AgNP-doped TiO₂-Fe₃O₄ embedded in an alginate–chitosan biopolymeric matrix for the removal of organic contaminants from water. The composite powders exhibited a nanocrystalline structure composed of anatase TiO₂ (~20 nm) and magnetite (~25 nm), with homogeneously dispersed Ag nanoparticles, as observed by SEM. The spheres presented a mainly submicrometric particle size distribution (0.55–0.92 µm), favoring high surface area and colloidal stability. Under simulated solar irradiation, the material achieved efficient photocatalytic degradation of methylene blue, with a pseudo-first-order rate constant of 0.112 h⁻¹ and ~46% decolorization after 5 h. UV-Vis spectra showed progressive attenuation of the dye absorption band without accumulation of intermediates. Magnetic recovery tests confirmed rapid separation and reuse without performance loss. The enhanced activity is attributed to the synergistic interaction among plasmonic Ag, photocatalytic TiO₂, redox-active Fe₃O₄, and the adsorptive carbon–biopolymer matrix. The material exhibited strong antibacterial activity, achieving over 90% removal of fecal coliforms after 5 h of irradiation. Therefore, the developed AgNP-doped TiO₂-Fe₃O₄ spheres represent a sustainable, reusable, and efficient material for solar-assisted water sanitation. Full article

This study investigates the coordinated impact of a synchronous condenser (SC), battery energy storage system (BESS), and static synchronous compensator (STATCOM) on enhancing voltage and frequency stability in a modified IEEE 9-bus power system under severe disturbances. The aim is to quantify the individual and combined contributions of these technologies during both fault ride-through (FRT) and load-increment events. The methodology includes dynamic modelling of all three devices in DIgSILENT PowerFactory. The SC is represented as a synchronous machine with inertia and AVR-based voltage control; the BESS employs converter-based active power and frequency-droop control; and the STATCOM provides fast reactive power injection through a dual-loop voltage regulator. Key indicators include nadir (minimum frequency), Rate of Change of Frequency (RoCoF), steady-state deviation, voltage sag depth, and recovery characteristics. Results indicate distinct roles for each device. The SC increases inertia and improves damping, but it also introduces small, well-damped oscillations. The BESS significantly enhances frequency stability by mitigating nadir, reducing RoCoF, and accelerating recovery, with negligible effect on voltage regulation. The STATCOM substantially reduces voltage sag and speeds up voltage recovery, but it does not influence frequency behaviour. When combined, the hybrid SC–BESS–STATCOM system demonstrates strong complementarity: the SC supports inertia, the BESS stabilizes active-power imbalance, and the STATCOM ensures fast reactive-power compensation. Full article

The circular valorization of biomass for sustainable energy recovery is a strategic priority in the transition toward low-carbon systems. In the last decade, anaerobic digestion (AD) has emerged as an efficient technology to produce an energetic vector to replace natural gas with biomethane and reduce waste; however, the hydrolysis of refractory fractions remains the main rate-limiting step. This study investigates an innovative electro-assisted pretreatment of biomass to promote the first rate-limiting hydrolysis step of refractory compounds in biomethane production. Lignocellulosic residues are employed not only as feedstock for the AD process but also as substrates in electrohydrolysis (EH) pretreatment using an Ir-Ta mixed metal oxide (MMO) anode coupled with advanced biomass-derived carbon felt cathodes. Two cathodes were functionalized with Phragmites Australis (PhA) hydrochars, untreated (PA) and KOH-activated (PA-KOH), to enhance the in situ generation of reactive oxygen species (ROS). Brassica napus (Bn) was chosen as the other biomass selected as a feedstock of AD, and was subjected to EH at varying energy inputs (500–5000 kJ·kg⁻¹), evaluating structural and biochemical shifts. The results demonstrate that EH effectively modifies the biomass matrix; the PA-KOH-CF cathode exhibited good selectivity to degrade lignocellulosic structures, but higher biomethane production was achieved at 2500 kJ·kg⁻¹ TS using PA-CF, reaching an increase of 52% compared with untreated samples. Kinetic analysis of the biomethane potential was performed using the modified Gompertz model. The model accurately captured the asymmetric sigmoidal transitions of methane production with different electrode configurations, and finally, energy balance assessment identified 2500 kJ·kg⁻¹ TS as the optimal operational threshold. These findings suggest that an excess of applied energy is critical to the availability of soluble organic matter and the presence of refractory compounds that reduce efficiency. This electro-assisted approach offers a robust strategy for intensifying AD, aligning with circular bioenergy objectives. Full article

Heavy metal pollution poses a serious threat to aquatic ecosystems. Microalgae have attracted considerable attention due to their dual potential for heavy metal removal and lipid recovery. However, studies that simultaneously achieve both heavy metal removal and lipid accumulation remain very limited. The short-term (3 h) and long-term (3 days) effects of single and mixed Cu²⁺, Zn²⁺, and Pb²⁺ stress on Chlorella vulgaris FACHB-8 were investigated for heavy metal removal and lipid recovery. Removal rates varied with metal species, concentration, and single vs. mixed systems. At 3 h, the order was Pb²⁺ > Cu²⁺ > Zn²⁺; at 3 days, Pb²⁺ ≈ Zn²⁺ > Cu²⁺. The Zn²⁺+Pb²⁺ combination maintained >90% removal across all concentrations, whereas Cu²⁺ removal was impeded (65–85%). Long-term stress maximized lipid content at 30% under 1 mg/L Cu²⁺ or 0.5 mg/L Cu²⁺+Zn²⁺, while Pb²⁺ restricted it to ≤12.85%. Cu²⁺ (1 mg/L) produced the highest saturated fatty acids (69.95%, dominated by C16:0 and C18:0), favorable for biodiesel. Highly toxic Pb²⁺ impaired cellular integrity and suppressed carbon allocation to lipids, whereas moderate Cu²⁺ or Cu²⁺+Zn²⁺ stress induced synergistic lipid and SFA accumulation. This metabolic shift was associated with upregulated superoxide dismutase (SOD) and acetyl-CoA carboxylase (ACC) activities, mitigating oxidative damage and redirecting carbon flux toward lipid biosynthesis as a defense strategy. Full article

Sustainable phosphorus (P) management in agriculture requires a circular economy approach through the use of so-called bio-based fertilizers (BBFs). The properties of BBFs vary widely depending on raw materials and production processes. However, it is still unknown how these properties, and particularly the dominant P compounds determine not only the efficiency of BBFs in supplying P to crops, but also their effects on soil functioning and crop quality. This study aimed to evaluate the efficiency of a representative set of BBFs, and relate this efficiency to their composition and dominant P compounds. To this end, 14 BBFs were studied: four from water purification (struvite, vivianite, and sewage sludge with and without composting), four composts (municipal solid waste (MSW), vineyard residues, and two using olive husks), three vermicomposts (two homemade and one commercial), fish meal, digestate, and a commercial organic fertilizer. Phosphorus forms in BBFs were determined using ³¹P nuclear magnetic resonance spectroscopy (P-NMR). The BBFs were compared to a single superphosphate (SSP) in a pot experiment growing wheat in two different alkaline soils, one rich in iron (Fe) oxides and one rich in carbonates. The effects on critical elements in grain [magnesium, Fe, zinc (Zn), manganese, and copper] and enzyme activities related to soil functioning and P cycling were also assessed. The dominant P compound in the BBFs was orthophosphate (73.8–89.5% of the total P in the NaOH–EDTA extracts). The MSW had the highest polyphosphate content (4.1%), a complex inorganic P compound. The organic P content ranged from 9.2% (fish meal) to 25.5% (Moge). Sewage sludge and composted sludge contributed high levels of phosphonates (4.1 and 5.6% of extracted P). The most abundant organic P compound class was inositol hexakisphosphates (IHPs), and myo-IHP (phytate) was the dominant IHP stereoisomer (1.2–6.4%) followed by D-chiro-IHP and scyllo-IHP. Plant dry matter and grain yield with most BBFs were not significantly different from that of SSP in both soils, likely due to the high concentrations of phosphate in relatively soluble forms in most of the BBFs. Vivianite and sewage sludge resulted in significantly higher grain yield than SSP (43% and 40%, respectively) in the carbonate-rich soil, likely due to progressive phosphate dissolution, which decreased the precipitation rate of insoluble calcium (Ca) phosphates. The highest P recoveries were obtained with horse manure vermicompost (65% and 15% higher than SSP in the Fe oxide-rich and in the carbonate-rich soil, respectively), partially attributed to the decreased precipitation rate of insoluble Ca phosphates with the added organic matter. Some BBFs increased micronutrient concentrations in grains and most decreased the P-to-Zn ratio relative to SSP. Overall, phosphatase and β-glucosidase activities increased with carbon-rich BBFs. Most of the studied BBFs could effectively replace fertilizers from non-renewable sources, in some cases with better crop P recoveries. Furthermore, some BBFs could provide additional benefits to grain quality, in terms of micronutrient supply for humans, and soil functioning. Full article

Lipopeptide biosurfactants and petroleum sulphonates (PSs) have complementary molecular structures that can achieve ultralow interfacial tension (IFT), which is considered the primary mechanism for enhanced oil recovery (EOR). In this study, the phase behavior of lipopeptide compounded with PS/crude oil/water was investigated, which revealed that lipopeptide addition led to the formation of Winsor III middle-phase microemulsion. The synergistic mechanism of ultralow IFT and microemulsion formation enables the lipopeptide-compounded system (LASP) to achieve superior oil displacement efficiency compared with the regular alkaline/surfactant/polymer (ASP) flooding system. Core flooding results proved that under the same conditions, the LASP system increased oil recovery by 10.58% relative to the ASP system. Furthermore, when the ASP system could no longer improve recovery, switching to the LASP system provided an additional 9.55% oil recovery rate. Moreover, the LASP system exhibited superior wettability, interfacial activity, and anti-adsorption properties. These findings highlight the potential of lipopeptide biosurfactants as high-performance, environmentally friendly alternatives to synthetic surfactants in EOR processes. Full article

Heap bioleaching is widely used to extract copper from low-grade sulfide ores thanks to its operational simplicity, low cost, and environmental sustainability. However, current control strategies rely primarily on single-factor optimization and often overlook the synergistic interactions of multiple key parameters, such as ore particle size, pore structure, pH, temperature, microbial activity, and oxygen transfer efficiency. As a result, issues such as low recovery rates, extended leaching periods, and high operational costs persist. Moreover, the “gray-box” nature of heap systems impedes real-time monitoring of internal physical, chemical, and biological processes. In addition, empirical multi-parameter optimization is time-consuming and inadequate for capturing complex interdependencies. This review was conducted to systematically examine the key factors influencing heap bioleaching efficiency and critically evaluate recent advances in numerical simulation and intelligent control strategies. As a result, we identified a major research gap: the existing models—including microscale shrinking core models (SCMs), mesoscale pore-network models based on CT reconstruction, and macroscale continuum models—have inherent limitations. SCMs assume idealized spherical particles with uniform mineral distribution while neglecting pore structure evolution and biofilm dynamics. Mesoscale models offer detailed pore characterization but lack robust multi-physics coupling (thermal–hydro–mechanical–chemical–biological, or THMCB). Macroscale models rely on homogenization assumptions that oversimplify spatial heterogeneity and temporal variations in permeability. This analysis covers the relevant literature from 1985 to 2025, with a focus on three methodological scales (micro, meso, and macro) and their integration with machine learning approaches. A notable finding is that hybrid neural network models (e.g., BP and RBF architectures) outperform purely physics-based models in predicting leaching kinetics under varying operational conditions. However, their accuracy depends heavily on high-quality field data—a limitation rarely addressed in prior reviews. By clearly delineating these model-specific limitations and scale-dependent trade-offs, this review makes two unique contributions: a structured framework for selecting and coupling numerical methods according to process requirements and a roadmap for integrating artificial neural networks with multi-physics simulations to achieve real-time intelligent control of heap bioleaching. The findings offer both theoretical guidance and practical references for optimizing the processing of low-grade copper sulfide ores. Full article

This study examines how individual political predispositions and national mobilisation contexts jointly structure protest participation in contemporary Europe across the pre-pandemic, pandemic and post-pandemic periods. Using data from Rounds 9, 10 and 11 of the European Social Survey (2018–2023), the analytical sample includes 106,106 respondents from 33 countries. Descriptively, protest participation remains a minority behaviour, yet displays pronounced cross-national heterogeneity, with participation rates ranging from below 3% in several Central and Eastern European countries to nearly 20% in the most mobilised contexts and remains remarkably stable across rounds at approximately 8.5%. Building on resource mobilisation theory, political process approaches and New Social Movements perspectives, the analysis conceptualises protest participation not as an isolated behavioural act but as the outcome of interactions between individual resources, evaluative orientations toward democratic institutions and broader mobilisation environments. Logistic regression models, country fixed-effects specifications and multilevel models with random intercepts are used to assess these relationships. At the individual level, political engagement emerges as the strongest predictor of participation: higher political interest is associated with substantially higher protest propensity, while ideological self-placement indicates lower participation among respondents positioned further to the right. Younger age and higher education also increase participation. Lower satisfaction with democracy and stronger perceptions of inequality are consistently associated with protest behaviour, supporting grievance-based interpretations linked to democratic evaluations rather than material deprivation alone. Country fixed-effects and multilevel models confirm that these individual-level associations are robust within countries, while significant between-country variation persists (random-intercept SD = 0.554), indicating that national mobilisation environments shape baseline levels of protest participation. Multilevel results further reveal that protest participation was significantly lower during the pandemic period (Round 10) relative to the pre-pandemic baseline, with only partial recovery in the post-pandemic period. A cross-round comparison demonstrates that the core individual-level associations are stable across all three periods, indicating that these relationships reflect durable structural patterns rather than dynamics specific to any particular mobilisation cycle. Beyond this overall stability, the analysis identifies two theoretically informative exceptions: subjective financial difficulty is significant only in the pre-pandemic period and gender differences in protest participation attenuate over time—patterns consistent with broader shifts in protest repertoires during and after the pandemic. These findings make three contributions to the comparative literature on contentious politics. First, by extending the analysis across three ESS rounds, the study demonstrates the temporal robustness of individual-level determinants of protest—an empirical question rarely addressed in the existing literature. Second, the multilevel design with round fixed effects allows for direct estimation of pandemic-related suppression and post-pandemic recovery in protest activity at the aggregate level. Third, the cross-national scope and temporally structured comparison provide new evidence on how individual political predispositions interact with shifting mobilisation environments across a period of exceptional socio-political strain in Europe. Full article

Ascorbic acid (AA) or vitamin C is an important biomolecule that plays a crucial role in biological and physiological systems. Deficiency and/or excess of AA in the body can lead to severe diseases such as scurvy and gastrointestinal complications. Therefore, it is crucial to monitor the levels of AA in the body and supplements. Polyvinylpyrrolidone nickel oxide nanoparticles (PVP-NiONPs) are prepared and evaluated for their potential as nanozymes with peroxidase-like activity. o-Phenylenediamine (OPD) was used as a chromogen in the presence of hydrogen peroxide. The oxidized OPD was produced by ROS from PVP-NiONPs and H₂O₂. This was monitored using UV-vis spectra and by colour changes using the naked eye. AA reduced the oxidized OPD during its sensing. The UV-vis signal was linear for AA concentrations ranging from 40 µM to 400 μM. The limit of detection (LOD) for AA was calculated to be 0.11 μM using 3σ and the limit of quantification (LOQ) was 0.36 μM using 10σ indicating a very high sensitivity. The colorimetric sensor showed good reproducibility and a recovery rate between 92.3% and 102.6%, indicating high accuracy and reliability. The findings of this work confirmed that PVP-NiONPs possess enzyme-like activity and are a promising alternative for the quantitative, on-site detection of ascorbic acid. Full article

The escalating sophistication of ransomware requires defensive strategies that are both proactive against zero-day attacks and operationally efficient. Existing solutions often force a trade-off—sacrificing low false-positive rates for broad detection, or vice versa. This work introduces an integrated framework designed to transcend this limitation. Our dual-stage approach synergizes pre-encryption behavioral analysis with definitive post-encryption confirmation. The first stage employs a specialized artificial immune system (AIS) that monitors a curated set of 47 features, including API-call n-grams and file entropy dynamics, to identify malicious activity before file encryption begins. This pre-emptive analysis is complemented by an enhanced, cross-platform R-Locker mechanism, which uses Windows named pipes and symbolic links to deploy honeyfiles that trap ransomware during I/O operations, providing a high-fidelity trigger for automated containment. We subjected this framework to a rigorous evaluation against 3500 real-world ransomware samples and 12,000 benign applications. The results demonstrate a 98.2% detection rate with a 0.8% false-positive rate, achieving a mean response time of 1.3 s. A key finding is the framework’s efficiency on both Windows and Linux (the only platforms tested), with the AIS and R-Locker modules consuming a combined 101 MB of memory. While the system excels in real-time detection, we note that its current memory forensics capability for key recovery is incompatible with certain ransomware families due to architectural obfuscations. Our findings suggest that the integrated approach performs well under laboratory conditions; further real-world validation is required to confirm robustness in diverse environments. Full article

Japanese flounder (Paralichthys olivaceus) is an economically important species in China’s marine fishery industry. However, due to long-term intensive fishing, its wild population has declined sharply. Artificial stock enhancement has become a core measure for restoring its resources. This study aimed to investigate the effects of different immersion durations and concentrations of SrCl₂ solution (10, 20, 40, 80 mg/L) on strontium (Sr) deposition in the otoliths of P. olivaceus, and to systematically evaluate the impacts of Sr marking on the fish’s antioxidant capacity and digestive enzyme activity. The results showed that the otolith Sr/Ca ratio was positively correlated with marking concentration and duration; the optimal parameters were 40 mg/L for 4 days, with the Sr/Ca ratio returning to baseline after 30 days post-marking, and a 100% marking success rate. There were no significant differences in body length, body weight, or condition factor between the experimental groups and the control group (p > 0.05), but mortality was significantly increased in the 80 mg/L group. Digestive enzymes exhibited a dose-dependent response to Sr exposure, characterized by activation at low concentrations and inhibition at high concentrations; lipase was the most sensitive, with an inhibition threshold of 10 mg/L. Sr marking within the range of 20–40 mg/L for 4–8 days significantly activated the activity of T-AOC, CAT, GPx, and SOD (p < 0.05) and reduced MDA content, indicating that the antioxidant system was activated without causing persistent oxidative damage. In conclusion, Sr marking is a safe and efficient method for otolith marking in Paralichthys olivaceus. The recommended protocol is immersion in a 40 mg/L SrCl₂ solution for 4 days, followed by a 30-day recovery period in clean seawater before being used for stock enhancement evaluation. This study provides a scientific basis and technical support for assessing the effectiveness of stock enhancement in P. olivaceus. Full article

To mitigate large-scale blackout risks in urban distribution systems under typhoon-induced extreme weather and to reduce post-disaster restoration costs, this study proposes a resilience-oriented spatiotemporal co-optimization framework integrating transportation networks, power grids, and distributed energy resources. First, a city-scale typhoon spatiotemporal model is established, integrating static wind field, dynamic evolution, and trajectory-based mobility with urban-geometry-driven wind speed correction to characterize the spatiotemporal progression of extreme wind hazards. Second, the time-varying failure rates of distribution network components are quantified by explicitly accounting for network topology correlations, while the spatiotemporal dispatchability and output characteristics of distributed resources under disaster conditions are systematically modeled. Third, a pre-disaster proactive deployment model is formulated to minimize load curtailment costs and resource allocation expenditures. The model integrates active network reconfiguration with coordinated placement of distributed generation (DG) and mobile energy storage systems (MESSs), enabling resilience-enhancing pre-positioning strategies. Subsequently, a post-disaster restoration scheduling model is developed with the objective of minimizing unserved load. By embedding traffic flow constraints and optimal path computation under disrupted transportation conditions, the proposed framework realizes spatiotemporal coordination among MESSs, DG, and electric vehicles (EVs), thereby accelerating system-level recovery. Finally, the effectiveness of the proposed strategy is validated on a 51-node urban distribution system located in eastern coastal China, demonstrating significant improvements in restoration performance and resilience enhancement. Full article

Background: During the COVID pandemic increased rates of intensive care unit (ICU) admission, mechanical ventilation, caesarean delivery, and preterm birth among women with SARS-CoV-2 infection in pregnancy were recorded. Purpose: This study describes the clinical course and perinatal outcomes of pregnant women with COVID-19 across pre- and post-vaccination periods. Methods: This study included all pregnant women with confirmed SARS-CoV-2 infection who subsequently delivered at the University General Hospital of Larissa between March 2020 and May 2023. Demographics, comorbidities, gestational age at infection and at delivery, COVID-19 symptoms, need for hospitalization, obstetric complications, mode of delivery, and neonatal outcomes were documented. An assessment of ischemia-modified albumin (IMA) was performed in a subset of women. Results: A total of 327 women (including 14 twin gestations) were recorded. Most women experienced mild disease while a minority required hospital admission, or intensive care (1.8 and 0.3% for the studied population, respectively). Fever and upper respiratory symptoms predominated, while radiologic evidence of pneumonia was rare. Overall preterm birth (<37 weeks) occurred in 13% of pregnancies and caesarean section in about two thirds of deliveries. Neonatal outcomes were favorable, with low rates of neonatal intensive care unit (NICU) admission and no early neonatal deaths. IMA values were higher during acute infection and declined towards recovery. Conclusion: Pregnant women with COVID-19 in Central Greece had predominantly mild clinical courses and excellent perinatal outcomes. IMA may represent a biologically plausible marker of disease activity, but further studies are needed. Full article

The development of non-enzymatic glucose sensors for beverage analysis remains challenging due to insufficient active sites, poor conductivity, and limited stability in complex matrices. A nickel-carbon nanotube composite (Ni/CNT−600) was synthesized via in situ solvothermal deposition followed by pyrolysis at 600 °C under an inert atmosphere. The optimized Ni/CNT−600 featured uniform anchoring of Ni nanoparticles on CNTs through strong Ni–C and Ni–O–C interfacial bonds, validated by various characteristic techniques. The Ni/CNT−600 sensor exhibited exceptional sensitivity (538.48 μA mM⁻¹ cm⁻²) and an ultralow detection limit (0.003 μM) in 0.1 M NaOH at +0.65 V, surpassing many reported metal-based and enzymatic sensors. It demonstrated remarkable selectivity against key interferents (e.g., ascorbic acid, uric acid). In real beverage samples (orange juice, grape juice, cola, green tea, milk), recovery rates ranged from 95.6% to 112.8%. This work demonstrates a well-defined Ni-CNT synergistic interface that contributes to enhanced non-enzymatic glucose sensing performance, effectively addressing matrix complexity in beverages. Full article

The study compares the effects of the HSP60-derived mutated peptide (CIGB-258) and its wild-type peptide (E18-3) on preventing carboxymethyllysine (CML)- and ethanol (Et-OH)-induced hemorrhagic events and acute toxicity in zebrafish. The results suggest a 67% survivability and swimming recovery in CIGB-258-treated zebrafish compared to only 20% in the CML+Et-OH-treated group. No effect of E18-3 was noticed on CML+Et-OH-impaired zebrafish survivability and swimming ability. Similarly, no effect of E18-3 was noticed on the CML+Et-OH-disturbed blood oxidative and antioxidant variables. In contrast, CIGB-258 showed a notable 35% lower rate of oxidized contents, and 2.0-fold and 1.2-fold higher paraoxonase (PON) and ferric ion reduction activity (FRA), respectively, than in the E18-3 group. Also, the CML+Et-OH-induced dyslipidemia was substantially prevented by the CIGB-258, whereas no protective effect of E18-3 was noticed. Similarly, the CML+Et-OH-triggered hepatic inflammation, steatosis, kidney damage, severe gastrointestinal bleeding, and intestinal fibrosis were successfully mitigated by co-treatment with CIGB-258. Surface plasmon resonance analysis revealed a substantial binding affinity of CIGB-258 for HDL₂ and HDL₃, characterized by association rate constants (K_a) of 14.78 and 6.20 μM⁻¹s⁻¹, dissociation rate constants (K_d) of 0.35 s⁻¹ and 0.22 s⁻¹, and equilibrium dissociation constants (K_D) of 0.024 and 0.035 μM, respectively. In conclusion, CIGB-258 exerted a substantial impact on CML+Et-OH-triggered adverse events, with high affinity for HDL, whereas E18-3 exposure remained unaffected and failed to produce any beneficial effects. Full article