Search Results (13,399)

This research investigates the formation of an amorphous phase in a non-equiatomic aluminum-based alloy, Al₈₂Fe₁₂Cu₂Nb₂Co₂, synthesized via mechanical alloying. By utilizing minor additions of Nb, Co, and Cu, structural stability and “chemical complexity” effects are achieved in a matrix dominated by a single element (82% Al). Thermodynamic analysis reveals that a moderately negative mixing enthalpy (ΔHₘᵢₓ = −6.89 kJ/mol) and elevated configurational entropy (ΔSₘᵢₓ = 5.420 J/mol·K) are the primary thermodynamic drivers of amorphization, supplemented by a transitional-regime atomic size mismatch (δ = 4.82%). The evolution of the structure, morphology, and magnetic properties of mechanically alloyed amorphous Al₈₂Fe₁₂Cu₂Nb₂Co₂ as a function of milling time was systematically investigated using X-ray diffraction, scanning electron microscopy, Fourier-transform infrared spectroscopy, and a vibrating sample magnetometer. Full article

Chia seed mucilage (CSM) is a promising plant-derived hydrocolloid characterized by unique physicochemical and functional properties that are strongly influenced by the extraction methodology. In this research, an optimized sonication–freezing-assisted extraction (SFAE) process was developed to obtain mucilage while preserving its structural integrity. Results indicate that the extracted mucilage has a high total dietary fiber content of 75.87% and a moderate protein level of 8.71%. Fourier transform infrared spectroscopy (FTIR) confirmed the presence of hydroxyl and ionized carboxylate (COO⁻) groups associated with uronic acids, highlighting the anionic and polyelectrolyte nature of the system. Rheological characterization of optimized-CSM revealed Newtonian behavior in dilute solutions, indicating minimal intermolecular interactions and permitting accurate measurement of intrinsic viscosity and viscosity-average molecular weight. A critical overlap concentration (c** ≈ 0.2% w/v) was identified, marking the transition to semi-dilute regimes, chain entanglement, and the onset of shear-thinning and viscoplastic behavior. Functionally, the optimized-CSM exhibited high water holding capacity and competitive emulsifying properties (emulsion activity index (EAI): 62.50%; emulsion stability index (ESI): 49.32%), attributed to synergistic interactions between proteins and polysaccharides. Overall, this work provides new insights into how processing conditions influence the chemical composition and molecular structure, which fundamentally govern the rheological and functional performance of CSM. These findings underscore its potential as a versatile hydrocolloid for food and biomedical applications. Full article

Experimental diabetes models induced by streptozotocin (STZ) and alloxan are widely used in preclinical research; however, direct standardized comparisons in female rodents remain limited. The present study evaluated multiple chemical induction protocols in female Wistar rats, including STZ (40 and 65 mg/kg), STZ at the same doses combined with nicotinamide (110 mg/kg), and alloxan (130 mg/kg). Glycemic progression, oral glucose tolerance test, body weight evolution, oxidative stress markers, and multi-organ histopathology were assessed over a 14-day period. High-dose STZ (65 mg/kg) and alloxan produced rapid, sustained hyperglycemia (p < 0.0001), significant body weight reduction, increased lipid peroxidation (elevated MDA), nitric oxide overproduction, thiol depletion, and pronounced pancreatic and renal structural damage. In contrast, STZ–nicotinamide protocols generated moderate but stable hyperglycemia with partial preservation of islet architecture, attenuated oxidative imbalance, and improved systemic tolerability. Oral glucose tolerance test confirmed impaired glucose handling in the STZ–nicotinamide group, consistent with a type 2 diabetes-like phenotype rather than complete insulin deficiency. These results demonstrate that induction strategy critically determines metabolic stability, oxidative stress burden, and tissue remodeling patterns, supporting model selection according to specific experimental objectives. Full article

Among different non-carbon materials, due to their high corrosion resistance and chemical stability, titanium-based compounds, such as TiO₂, TiN, TiC and Ti₃C₂T_x, are potential supports for PEMFC catalysts. In addition to its main function as a support, due to its catalytic properties, TiO₂ is also used as co-catalyst/additive in the catalyst layer. In this work, the use of titanium compounds as catalyst supports and co-catalysts in the membrane electrode assembly of PEMFCs is overviewed and discussed. Full article

To address the slow curing and low early strength of conventional modified epoxy emulsified asphalt repair materials, this study introduced steel slag aggregate into epoxy emulsified asphalt mixtures. Experimental techniques including heat absorption–heat transfer rate tests, Marshall stability tests, COMSOL numerical simulation, and scanning electron microscopy (SEM) were adopted to analyze rapid and uniform heating under microwave radiation. The influence of steel slag’s chemical composition, content, and particle size on epoxy curing, asphalt demulsification, and early strength of the mixture was systematically examined. Results show that steel slag containing Fe and Mg elements exhibits higher microwave absorption efficiency. When its content exceeds 15%, the heating rate increases by approximately 0.335 °C/s under the tested conditions. Particles sized 0.6~2.36 mm show better wavelength matching with the applied microwave frequency (2.45 GHz), thereby enhancing absorption. After 140 s of microwave radiation, the core temperature of the mixture reaches 110 °C, which is the appropriate temperature to achieve rapid epoxy curing and synchronous asphalt demulsification. These two processes synergistically form a continuous network structure, thereby improving the compactness and initial laboratory Marshall stability of the mixture. Nevertheless, this study has several limitations. The microwave absorption efficiency depends strongly on the specific mineralogy and Fe/Mg content of steel slag, both of which may vary with source. The conclusions are based on laboratory-scale tests under fixed microwave power and mixture proportions. Despite these limitations, the results demonstrate that steel slag can serve as an effective microwave-absorbing component in epoxy emulsified asphalt mixtures, enabling rapid curing and demulsification to accelerate early strength development. Full article

The growing interest in clean-label and naturally preserved foods has pushed the scientific community to research essential oils (EOs) as sustainable, multifunctional alternatives to chemical preservatives. These plant volatile compounds exhibit strong antimicrobial and antioxidant activities, making them promising ingredients for natural preservation. Fermented meat products, though highly nutritional, are particularly at risk of microbial spoilage and contamination by foodborne pathogens due to their complex microbiota and processing conditions. This review examines the role of EOs as natural antimicrobials in fermented meat systems, summarizing their mechanisms of action, efficiency against key pathogens, and impact on safety, shelf life, and sensory attributes. Additionally, it discusses technological challenges related to volatility, stability, and sensory alterations, and outlines mitigation strategies such as encapsulation, nanoemulsions, and controlled-release delivery systems. By critically presenting current progress and identifying research gaps such as standardization and matrix interactions, this review contributes to the development of effective, natural, and clean-label preservation strategies. These insights support innovation and sustainability in the meat processing industry by bridging the gap between antimicrobial efficacy and sensory acceptability. Full article

Global energy de-fossilization requires scalable solutions for extended energy storage and industrial emission reduction. Synthesizing green methane via Power-to-Gas technology offers a viable pathway to store renewable electricity while utilizing captured carbon dioxide. This review evaluates recent advancements in catalytic mechanisms, reactor engineering, artificial intelligence applications, and techno-economic and life cycle assessments of green methane production systems. Analysis shows that advanced reactor configurations effectively manage the exothermic heat of the Sabatier reaction. Furthermore, integrating machine learning algorithms accelerates catalyst discovery and enables dynamic process control under fluctuating renewable energy loads. Economic and environmental assessments indicate that the sustainability of green methane depends strictly on utilizing renewable electricity and sourcing non-fossil carbon. Commercial deployment must focus on improving catalyst stability during transient operations and implementing digital twins to establish green methane as a sustainable carbon backbone for chemical industries. Full article

Environmental pollution constitutes an increasingly complex global challenge, largely driven by industrial expansion and the consequent release of toxic species such as Cd²⁺, Pb²⁺, Cu²⁺, Hg²⁺, Fe³⁺, As³⁺, and Rh³⁺ into natural ecosystems. These contaminants pose significant risks to environmental integrity and public health, motivating the development of analytical technologies capable of sensitive, selective, and reliable detection. In this context, graphene-based electrochemical sensors have emerged as versatile platforms for monitoring a broad range of analytes, particularly in environmental applications involving heavy-metal detection. The intrinsic physicochemical properties of graphene derivatives have enabled low detection limits, rapid response times, and tunable selectivity. Despite analytical advances, critical challenges persist regarding operational stability in complex matrices, inter-batch reproducibility, and robustness to interfering species, which continue to hinder large-scale deployment and real-world applicability. However, challenges remain regarding stability and performance in complex arrays, reproducibility, and resistance to interference, necessitating innovative strategies for functionalization and molecular recognition. This review article establishes a comparative framework based on functionalization strategies (covalent, non-covalent, and hybrid), the chemical nature of graphene (GO, rGO, and doping), and various types of polymers (conductors and insulators), using statistical metrics such as the limit of detection (LOD), linear range, working potential, stability, and interferences, employing a bibliometric analysis using the PRISMA 2020 methodology. This comparative framework enables analysis and explanation of performance trends, and the generation of design and functionalization recommendations for versatile applications, including criteria for reproducibility and sustainability. Full article

Thyme (Thymus callieri Borbás ex Velen) and summer savory (Satureja hortensis L.) are aromatic plants from the Lamiaceae family widely used in traditional medicine and the food industry. This study provides a comparative analysis of the phytochemical profiles and biological potential of the essential oils (EOs) of these two plant species from Bulgaria. The chemical composition was determined using GC-MS analysis. Biological evaluation included determination of antioxidant activity (DPPH assay), antimicrobial activity (MIC assay), ex vivo anti-inflammatory effects (IL-1β expression in rat stomach smooth muscle preparations), and in vitro antihemolytic activity. GC-MS analysis identified 16 compounds in T. callieri EO, dominated by p-cymene (46.42%) and thymol (35.80%). In contrast, 17 compounds were identified in S. hortensis EO, with carvacrol (58.81%) and γ-terpinene (22.46%) as major constituents. Both EOs exhibited concentration-dependent antioxidant activity, with S. hortensis showing higher radical scavenging potential. In antimicrobial tests, both oils demonstrated broad-spectrum efficacy with MIC values ranging from 0.313 to 2.5 mg/mL. Ex vivo experiments revealed that T. callieri EO significantly increased IL-1β expression, suggesting immune activation, while S. hortensis EO showed a lower effect, indicating higher anti-inflammatory potential. Furthermore, S. hortensis EO demonstrated superior erythrocyte membrane stabilization (antihemolytic activity) compared to T. callieri EO and the reference anti-inflammatory drug Aspirin. In conclusion, the findings highlighted the distinct biological potential of both Bulgarian EOs, suggesting their diverse applicability as natural bioactive agents in the pharmaceutical and food industries. Full article

This review comprehensively examines magnetic nanomaterials, ferrofluids, and their integration into ferrogel systems, systematically exploring their structural characteristics, dynamic behaviors, preparation techniques, and applications across medical and engineering fields. Structural characterization reveals that particle size and dispersibility directly influence functional efficiency in fluid and gel matrices, such as SAR (specific absorption rate) values in hyperthermia applications. For ferrofluids and magnetic gels, macroscopic behaviors and microscopic mechanisms are governed by key parameters like the magnetic Bond number. Preparation encompasses green synthesis, chemical reagent synthesis, and the cross-linking of these nanoparticles into hydrogel networks. Applications span diverse areas: in medicine, these include targeted hyperthermia, pH-responsive magnetic gel drug delivery, and MRI (magnetic resonance imaging); in engineering, applications range from efficient extraction and triboelectric power generation to magnetically regulated heat transfer and soft gel robotics. The paper also discusses current challenges, including material stability and unclear micro–macro correlations in complex fluid–gel systems, outlining future research directions for multifunctional magnetic materials. Full article

The continuous increase in atmospheric CO₂ concentration exacerbates global climate change, making carbon reduction an urgent global priority. Carbonic anhydrase (CA), a highly efficient biocatalyst that converts CO₂ into bicarbonate, demonstrates significant potential for carbon capture and resource utilization. However, the stability and catalytic efficiency of native CA in industrial environments are limited, particularly its poor thermal tolerance under flue gas conditions and its sensitivity to impurities, hindering its direct large-scale application. This review systematically summarizes recent advances in modifying microbial CA through protein engineering (e.g., directed evolution, rational design) and immobilization techniques, which have markedly enhanced its thermal stability, adaptability, and reusability. Among these, the integration of machine learning with high-throughput experimentation has emerged as a transformative strategy for CA engineering. Furthermore, we outline CA-driven pathways for CO₂ conversion into high-value chemicals and bioenergy. Finally, future prospects are discussed, including interdisciplinary integration, computational modeling coupled with experimental validation, and comprehensive life-cycle and techno-economic assessments, to facilitate the scaled application of engineered microbial CA in carbon neutrality pathways. Collectively, this review highlights the critical role of engineered CA in bridging biocatalysis with industrial carbon management, offering a viable and sustainable pathway toward carbon neutrality. Full article

Alkaloids are structurally diverse, nitrogen-containing plant secondary metabolites with well-documented insecticidal activity. This review examines alkaloid-based insecticides, focusing on their chemical diversity, biosynthetic origins, plant distribution, and physicochemical properties relevant to pest control on farms. The principal molecular targets and modes of action are discussed, including interactions with nicotinic acetylcholine receptors, acetylcholinesterase, ryanodine receptors, and GABAergic signaling. Another focus is key metabolic enzymes, together with their activity spectra against major agricultural pests. Recent advances in rational structural modification, supported by crystallographic data, computational modeling, and structure–activity relationship studies, are highlighted as strategies to enhance the potency, selectivity, and stability of these compounds. Toxicological profiles, food residue behavior, analytical challenges, and regulatory considerations are critically assessed, emphasizing that natural origin does not equate to inherent safety. The review further evaluates the role of alkaloid-based insecticides within integrated pest management systems and identifies key research gaps related to environmental safety, non-target effects, and regulatory development and harmonization. It concludes that alkaloids are positioned as potentially valuable tools for sustainable agriculture when deployed within science-based regulatory frameworks and integrated control strategies. Full article

Quantifying time-dependent rock mass degradation is critical for assessing long-term slope stability during open-pit mine closure. This study evaluates the geotechnical evolution of Paleoproterozoic arenites and argillites in the semi-arid Essakane Main Zone (Burkina Faso) over a 0–9-year atmospheric exposure period. Field characterization across 32 sampling stations included density measurements, point load testing (Is₍₅₀₎), determination of the Geological Strength Index (GSI), and petrographic analysis. The results demonstrate a time-dependent reduction in physico-mechanical properties, modeled with a high correlation (R² = 0.80–0.99). While density exhibited minor reductions, structural degradation was pronounced; the GSI decreased by 10 points for both lithologies, and Is₅₀ dropped significantly, particularly in argillites (4.1 to 2.3 MPa) relative to arenites (4.0 to 3.6 MPa). Petrographic evidence indicates negligible chemical weathering and mineral neoformation. Consequently, the degradation was attributed primarily to physical processes, specifically microcracking and discontinuity deterioration driven by thermal cycling and phyllosilicate sensitivity in argillites. These empirical relationships provide essential quantitative input for numerical slope stability modeling in semi-arid mine closure scenarios. Full article

This article presents the results of the development of an antibacterial coating based on polyvinylpyrrolidone (PVP) and polyethylene glycol (PEG) fibers with embedded silver nanoparticles. Silver nanoparticles were synthesized via the use of PEG, which acts as a reducing agent for Ag⁺ ions and a stabilizer for the colloidal system. The resulting sols were pink, dark purple, and orange color. The viscosity of the compositions, which increased with increasing PEG and AgNO₃ concentrations, was studied. The sizes of the synthesized silver nanoparticles were determined via dynamic light scattering. For all compositions, monomodal particle size distributions were obtained with characteristic sizes of 50.75, 58.73, 13.54 and 28.21 nm. The highest ζ-potential value for the silver nanoparticles was ‒15.5 mV, indicating their stability. The electrical conductivity of the compositions increased with increasing molar concentration of AgNO₃. The resulting PVP-PEG compositions with silver nanoparticles demonstrated resistance to pathogenic bacteria such as Staphylococcus aureus and Escherichia coli. A portable electrospinning device was developed at the Mendeleev University of Chemical Technology of Russia to apply the compositions to the skin and form a protective coating of PVP-PEG fibers with an antibacterial effect. Fiber formation was confirmed by scanning electron microscopy. The incorporation of silver into the fiber structure was confirmed by the results of elemental analysis and surface mapping of the samples. Full article

The goal of this work was to determine the effect of soil freeze–thaw processes on the formation of water-stable aggregates (WSA) and plant available water (PAW) in soils of different textures, depending on the intensity of tillage: conventional tillage (CT), reduced tillage (RT) and no-tillage (NT). The WSA value (0.4%) and PAW mean (5.5%) in sandy loam were higher than in loam. The average content of WSA and PAW tended to decrease in the following order: air-dry soil > soil with water content at field capacity > soil near full saturation. These results indicate that WSA in soils that are close to full saturation upon freezing will be less stable after thawing and will decrease the PAW. The content of WSA in NT was 9.4% higher than in RT and 14% higher than in CT. The content of PAW in NT was 5.6% higher than in CT and 13.6% higher than in RT. The effects of various physical and chemical properties on PAW as a function of water level during the freeze–thaw process indicate that WSA content acted as a direct factor for PAW. In a temperate climate zone under dry meteorological conditions, NT would have a promising future for soil stability by maintaining higher WSA and PAW. Full article