Search Results (58,976)

To enhance flame retardancy of waterborne polyurethane (WPU) coatings, this paper proposes a co-modification method using modified graphene oxide (SiO₂@GO) and a phosphorus flame retardant (P-). SiO₂@GO refers to graphene oxide (GO) with an attached silicon dioxide (SiO₂) layer, while the phosphorus flame retardant (P-) in this work is THPO, a reactive flame retardant used as a chain extender. The influence of component additions on flame retardancy was systematically investigated. Modified WPU coatings (P-SiO₂@GO/WPU) were prepared using THPO and SiO₂@GO as flame-retardant chain extenders. The morphology, structure, and thermal stability of P-SiO₂@GO/WPU were characterized by scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy, and thermogravimetric analysis (TGA). At 2% SiO₂@GO, coatings showed enhanced hydrophobicity (water repellency) and thermal stability. With 4% phosphorus flame retardant (P-), the limiting oxygen index (LOI, a measure of flame retardancy) reached 32.2%, and the heat release rate was 32.4% lower than before modification. A continuous, dense P/Si-containing carbonaceous ceramic-like barrier layer was formed, effectively blocking the release of combustible gases and the transfer of heat, thereby demonstrating excellent flame retardancy. This synergistic P-SiO₂@GO/WPU modification offers theoretical support and practical guidance for optimizing and enhancing the flame-retardant performance of WPU coatings. Full article

Background/Objectives: Bone infection remains a severe clinical challenge characterized by recurrence, antimicrobial resistance, and high morbidity, driving the search for new therapeutic strategies. Despite advances in developing biomaterials with suitable biocompatibility, biodegradability, and structural properties, the lack of effective antibacterial activity continues to significantly limit the treatment of bone defects. To overcome this issue, we investigated the incorporation of silver-based nanostructures into calcium polyphosphate/alginate (CPP/Alg) matrices as an antibacterial reinforcement strategy for bone-related applications. Methods: Silver nanoparticles (AgNPs) were synthesized in aqueous medium via NaBH₄-mediated chemical reduction, using either alginate (Alg) or sodium polyphosphate (PP) as stabilizing agents, enabling a comparative evaluation of biocompatible polymer- and polyphosphate-stabilized systems. Subsequently, AgNPs were incorporated into calcium polyphosphate/alginate (CPP/Alg) matrices to obtain Ag-containing composites. Results: The AgNPs exhibited spherical morphology, Zeta potential values ranging from −38.7 ± 0.2 to −23 ± 0.3 mV, and hydrodynamic diameters between 25.2 ± 0.2 and 143 ± 5 nm. Structural characterization of the biocomposites by X-ray diffraction confirmed hydroxyapatite as the major crystalline phase, while Raman spectroscopy revealed vibrational bands corresponding to both the inorganic and polymeric components. SEM revealed a dense, rough surface, and ICP-OES analysis confirmed the presence of Ag. Antibacterial activity assays demonstrated effective growth inhibition of Staphylococcus aureus and Staphylococcus epidermidis, with inhibition halos growing with increasing composite dosage. Notably, antibacterial activity was achieved at relatively low Ag contents, underscoring the efficiency of these biocomposites. Conclusions: These findings confirm the effective incorporation of AgNPs into the CPP/Alg matrix and support the classification of composites as promising antibacterial biomaterials for bone regeneration applications. Full article

Hepatocellular carcinoma (HCC) is among the most prevalent and lethal malignancies worldwide, with limited therapeutic outcomes due to systemic toxicity and suboptimal efficacy of conventional chemotherapeutics such as doxorubicin (DOX). In this study, we formulated and standardized DOX-loaded chitosan/poly (lactic-co-glycolic acid) nanoparticles (DLCNs) via a nanoprecipitation method and evaluated their therapeutic potential in a diethylnitrosamine (DEN)-induced Wistar rat model of HCC. Physicochemical analyses confirmed nanoscale size, favorable zeta potential, and high encapsulation efficiency, while Fourier-transform infrared spectroscopy (FTIR) verified polymer–drug interactions. Biochemical analysis revealed that DLCNs significantly normalized elevated liver function markers (Aspartate aminotransferase (AST), alanine aminotransferase (ALT) and alkaline phosphatase (ALP), restored serum α-fetoprotein (AFP) to near-control levels, and reduced lipid peroxidation compared with free DOX and DEN controls. Antioxidant profiling demonstrated marked recovery of superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx), indicating restoration of hepatic redox balance. Histopathological evaluation further corroborated these findings, showing recovery of hepatic lobular architecture and reduction in necrosis and inflammatory infiltrates in DLCN-treated Wistar Albino rats, while free DOX groups exhibited hepatocellular damage. Overall, the results demonstrate that encapsulating DOX in a chitosan/PLGA nanocarrier improves therapeutic efficacy, mitigates hepatotoxicity, and enhances antioxidant defense, establishing DLCNs as a favorable candidate for HCC. Full article

Expansion of the operational temperature range for polymer-electrolyte membrane fuel cells (PEMFCs) above 200 °C significantly reduces hydrogen purification requirements. Here, we report a hybrid composite of poly(2,5-benzimidazole) (ABPBI) and CsH₂PO₄, doped with H₃PO₄, as a PEM for PEMFC operation at >200 °C up to 250 °C and beyond. The optimal ratio of ABPBI repeating units to CsH₂PO₄ is 1:1 (mol/mol). Materials are extensively characterized by elemental analysis, scanning electron microscopy, HAADF STEM, elemental mapping, electrochemical impedance spectroscopy, proton conductivity, mechanical testing, and Fourier transform infrared spectroscopy. It is suggested that PEMFCs with the extended operational temperature range (>220 °C) might be categorized as ultrahigh-temperature polymer-electrolyte membrane fuel cells (UT-PEMFCs). Full article

The incorporation of ground tire rubber (GTR) into elastomeric compounds offers a sustainable route for recycling end-of-life tires; however, its effect on the structure–property relationships governing mechanical and dielectric performance remains insufficiently understood. In this study, NR/SBR composites containing 0–50 phr of devulcanized GTR were prepared and characterized through Fourier-transform infrared spectroscopy (FTIR), swelling analysis, thermogravimetric analysis (TGA), mechanical testing, and broadband dielectric spectroscopy. FTIR and swelling results revealed enhanced matrix–GTR interaction at intermediate GTR loadings (10–20 phr), evidenced by an increased intensity of sulfur-related bands and reduced swelling degree, indicating partial chemical integration of the recycled phase into the elastomer network. Mechanical testing showed that increasing GTR content increased stiffness at high loadings, while tensile strength, elongation at break, and toughness progressively decreased due to interfacial debonding mechanisms. TGA demonstrated that the main degradation temperature of the NR/SBR matrix remained essentially unchanged (418–425 °C) across all formulations, confirming preservation of thermal stability despite increasing structural heterogeneity. Dielectric spectroscopy (10⁻²–3 × 10⁶ Hz, 40–120 °C) revealed pronounced Maxwell–Wagner–Sillars interfacial polarization and thermally activated charge transport, with conductivity increasing with GTR content without evidence of electrical percolation, even at 50 phr. The results demonstrate that the performance of NR/SBR/GTR/SiO₂ composites is primarily controlled by the interfacial structure generated by the recycled phase. Intermediate GTR contents (10–20 phr) provide the most effective matrix–GTR interaction, while higher loadings mainly affect mechanical integrity and dielectric response through increased structural heterogeneity. These findings provide practical guidelines for designing sustainable elastomeric compounds with high recycled content while maintaining thermal stability and controlled electrical insulation properties. Full article

Melamine, characterized by its high nitrogen content, has been illegally added to food and feed to falsely increase apparent protein levels. However, melamine and its metabolites pose serious risks to human and animal health, including kidney stones, renal failure, and even death, as well as potential carcinogenic effects. Therefore, accurate detection of trace melamine is of great importance and urgency. Electrochemical sensors based on nanomaterials have been widely used for melamine detection due to their high sensitivity, good selectivity, rapid response, and simple operation. In this work, a composite nanosheet-structured electrode was fabricated, and a dense layer of gold nanoparticles was modified on its surface to enhance electrochemical performance. Cyclic voltammetry and electrochemical impedance spectroscopy measurements indicated that this electrode exhibited highly sensitive electrochemical properties. In addition, differential pulse voltammetry was employed for melamine detection, and the results showed a wide linear range of 20–500 nM with an LOD of 4.7 nM. The proposed electrode enabled the detection of melamine in milk samples, exhibiting good anti-interference ability and long-term stability. Full article

This study reports the physicochemical characterization and structure–property relationships of rigid sheep wool/phenolic novolac panels developed as bio-based thermal insulation for building envelopes. Mixed Polish sheep wool was washed, mechanically opened, and formed into nonwoven mats, then impregnated with either neat or flame-retardant novolac resin to obtain lightweight boards with a fiber content of about 50 wt%. Elemental analysis, ICP-OES, FTIR spectroscopy, and laser and electron microscopy were used to evaluate the fiber composition, keratin structure, morphology, and fiber–matrix interfaces. Mechanical performance under three-point bending and shear, differential scanning calorimetry, thermogravimetric analysis, and transient hot-probe thermal-conductivity measurements were applied to link microstructure with functional behavior. Novolac impregnation transformed the compliant wool mat into self-supporting panels, increasing the flexural modulus to the 0.8–1.4 GPa range and flexural strength to approximately 48–52 MPa, while the shear modulus and work to failure rose by more than an order of magnitude relative to the loose wool reference. Thermal conductivity remained in a typical range for natural-fiber insulations (λ = 0.061 W·m⁻¹·K⁻¹ for the wool mat and 0.071–0.074 W·m⁻¹·K⁻¹ for the composites), although higher than that of expanded polystyrene. DSC and TGA confirmed that wool fibers remain thermally stable up to about 200–220 °C, that the novolac resin cures around 140 °C, with typical phenolic reaction enthalpies, and that both formulations generate high char residues of roughly 60–80 wt% at 600 °C under nitrogen, evidencing a strong charring propensity rather than directly quantifying fire resistance. Overall, the results position sheep wool/novolac panels between conventional bio-based insulation and structural composites and highlight their potential as sustainable, circular insulation materials for energy-efficient building envelopes. Full article

Second-generation high-temperature superconducting tapes (2G HTS; SuperPower Inc., New York, NY, USA) based on GdBCO (GdBa₂Cu₃O_7−δ, where δ denotes oxygen deficiency) were aged at −26.4 °C, +2 °C, and room temperature (RT) to evaluate the degradation of their superconducting properties. HTS tapes stored at RT exhibited a significantly higher deterioration rate compared to those maintained at lower temperatures. Laser-induced breakdown spectroscopy (LIBS) analysis demonstrated a gradual reduction in the effective chemical depth-profiling length over time, indicating a correlation between the degradation mechanism and the reduction in the effective volumetric density of the GdBCO superconducting layer. These findings imply that oxygen diffusion or redistribution processes substantially contribute to the long-term degradation of GdBCO-based HTS tapes. Full article

Applying sludge from wastewater treatment plants to agricultural soils is a major pathway for microplastics (MPs) to reach terrestrial ecosystems, with critical implications for food and environmental safety. A longitudinal analysis (13 months) was conducted to evaluate vermicomposting (with Eisenia andrei) as a remediation strategy, comparing fresh sludge, worm casts, mature vermicompost, and control (earthworm-free) compost. MPs were isolated by chemical digestion and density separation and characterized by optical microscopy and μ-Raman spectroscopy. The MP content of fresh casts (584 ± 45 MP·g⁻¹; p = 0.036), driven by the mechanical and digestive activity of earthworms, showed a significant increase relative to sludge, in contrast to the invariant results observed in the control compost. The MP content of the vermicompost initially increased to 755 ± 88 MP·g⁻¹ after 3 months of maturation due to gradual fragmentation by microbial degradation. However, after 13 months, the MP content in vermicompost, compared to the initial sludge, decreased by 62% (reduction of 625 ± 49 MP·g⁻¹; p < 0.001), more than the 56% (reduction of 560 ± 83 MP·g⁻¹; p = 0.001) observed in the control compost, suggesting a net long-term decrease. Morphological, colorimetric, and compositional changes, reflected by browning and reduced particle size and natural fiber content, revealed a temporal lag, with earlier transformation in vermicomposted samples. Overall, the findings show the potential of vermicomposting to reduce the MP content of sewage sludge used as a soil amendment. Full article

Hydroxypropyl methylcellulose hydrogels were designed as polymeric matrices for porphyrinic photosensitizer samples (5-(2-hydroxy-5-methoxyphenyl)-10,15,20-tris-(4-carboxymethylphenyl) porphyrin (P3.2) and 5,10,15,20-tetrakis-(4-carboxymethylphenyl) porphyrin (P3.1) to investigate their physicochemical behavior and structure–property relationships. Fourier transform infrared, UV–Vis, and fluorescence spectroscopy showed that both porphyrins remained monomerically dispersed in the polymeric matrix by establishing moderate interactions with HPMC by hydrogen bonding. X-ray diffraction and atomic force microscopy showed the uniform microstructural organization of the hydrogel matrix, while thermal analyses confirmed the stability of both studied systems. Rheological measurements demonstrated that the incorporation of porphyrins in the hydrogel network slightly modulates viscoelastic behavior. The swelling, density, and pH studies highlighted correlations between molecular interactions and macroscopic hydrogel properties. The swelling ratio determined after 6 h showed values of about 89% for the hydrogel of HPMC with P3.1. and about 92% for the hydrogel of HPMC with P3.2, respectively. The pH value was found to be 7.0 for both hydrogels. These results highlighted interfacial and physicochemical insights into polymer–porphyrin interactions in hydrogel matrices. All studies show that a controlled dispersion of chromophores preserves their monomeric state and controlled structure–property relationships. Full article

This study investigates the development of a functional hummus enriched with black cumin seed oil (Nigella sativa) and evaluates its physicochemical properties and oxidative stability during 21 days of refrigerated storage. Additionally, the applicability of near-infrared (NIR) spectroscopy as a rapid and non-destructive analytical tool for hummus quality assessment was examined. Hummus samples were prepared by partially replacing olive oil with black cumin seed oil at levels of 4, 6, 8, and 12% (v/v). Chemical composition, peroxide value, and water activity were monitored over time, while multivariate statistical methods (Principal Component Analysis and Partial Least Squares Regression) were used to correlate NIR spectral data with reference measurements. The results showed that the incorporation of black cumin seed oil did not significantly affect the overall macronutrient composition but altered the fatty acid profile by increasing the content of polyunsaturated fatty acids. Oxidative changes were observed during storage, with peroxide values increasing after day 7, while samples with higher levels of black cumin seed oil exhibited improved oxidative stability in later stages. Water activity remained constant across all formulations. NIR spectroscopy demonstrated high predictive accuracy for fat, protein, carbohydrate, and dietary fiber content (R² > 0.99), while lower performance was observed for water activity and dry matter. The findings confirm the potential of NIR spectroscopy for rapid quality monitoring of functional plant-based spreads. This study highlights the feasibility of developing a functional hummus enriched with black cumin seed oil and supports the application of NIR spectroscopy as an efficient tool for monitoring compositional and oxidative changes during storage. Full article

In Italy, the apple cider market is experiencing significant growth, driven by numerous small-scale artisanal producers who combine local apple varieties with traditional processes to offer complex, and diverse products. However, artisanal production based on spontaneous fermentations often encounters challenges in qualitative reproducibility, particularly related to sensory issues (stability across different vintages and high turbidity of the product). In this context, a methodology has been developed to optimize the technological process of cider production at Contrada Contro in the Monti Sibillini (MC), in Marche region, Italy. The research focused on the isolation and selection of indigenous yeasts from frozen must prepared in the 2023 vintage. Following isolation and preliminary characterization, the indigenous yeasts were used to referment the still cider, followed by 7 months of bottle aging, and a second sampling point was conducted after 14 months of aging on lees. Destructive analyses using HPLC-DAD and GC-MS were conducted to evaluate polyphenols and volatile compounds, while non-destructive analyses with a 12-quartz microbalance electronic nose and near infrared (NIR) spectroscopy allowed for a quicker assessment of production techniques. Chromatographic analysis results showed that the sensory quality of refermented products was strongly influenced by the composition of the yeast strains used. All fermentations inoculated with selected yeasts exhibited lower turbidity compared to spontaneous fermentation. These findings indicate that the selection of indigenous yeasts for cider refermentation enables the production of a high-quality product, enriched with beneficial compounds and characterized by a strong terroir identity, underscoring the importance of microbiological terroir. Full article

Cosmetic preservatives should have reduced percutaneous absorption to lower the risk of systemic exposure and skin irritation. In this work, previously synthesized galactosylated derivatives of common cosmetic preservatives were comparatively evaluated for transdermal permeation and preliminary toxicity. Escherichia coli β-galactosidase was used to enzymatically modify several of the commonly used cosmetic preservatives to produce their corresponding galactosylated derivatives: benzyl alcohol β-d-galactopyranoside 7, 2-phenoxyethanol β-d-galactopyranoside 8, chlorphenesin β-d-galactopyranoside 9, 1,2-hexanediol β-d-galactopyranoside 10, 1,2-octanediol β-d-galactopyranoside 11, and 2-phenylethyl β-d-galactopyranoside 12. HPLC and NMR spectroscopy were used to analyze the previously synthesized derivatives. The Franz diffusion cell assay was used to evaluate skin penetration. 2-Phenoxyethanol (PE), chlorphenesin (CPN), and 2-phenylethanol (PhE), showed measurable skin penetration, with flux values ranging from 3.82 to 7.34 µg·h⁻¹·cm⁻² and permeability coefficients (Kp) between 1.38 and 3.00 × 10⁻³ cm·h⁻¹. In contrast, their galactosylated derivatives showed markedly reduced permeation under the same experimental conditions. Moreover, brine shrimp lethality assays indicated that galactosylated derivatives had significantly higher LD₅₀ values (1.6–2.1 mg/mL) than their parent compounds (0.1–0.79 mg/mL), suggesting lower cytotoxicity. These findings suggest that enzymatic galactosylation can significantly decrease skin permeability and the toxicity of cosmetic preservatives, highlighting its potential approach to improve the safety of cosmetic components. Full article

Tobacco is a plant with a wet stigma, which produces reactive oxygen species (ROS) and abscisic acid (ABA) which is important for in vivo pollen germination. Furthermore, ROS can be linked to growth processes, stimulating or inhibiting them. However, to what extent do differences in the redox environment and ABA level on the stigma and in pistil tissues correlate with flower growth, pollination success and resulting fruit parameters? We investigated redox homeostasis and ABA concentrations in stigma exudates of two tobacco lines (“Samsun” and “Fortune”) with different floral organ size and seed production. Fortune has longer flowers, larger fruits, and more seeds than Samsun. We report here that Samsun has a higher total oxidative capacity in stigma exudate, and possibly also higher NO level, than Fortune, as estimated by electron paramagnetic resonance spectroscopy. Fortune has a higher ascorbate peroxidase (APX) content in stigma tissues, as determined by Western blot analysis, and a higher ABA concentration in stigma exudate. Analyzing ROS levels and enzyme activity during the elongation stage in buds, we found that shorter Samsun styles had higher ROS levels, but they also had higher superoxide dismutase (SOD) and APX activity. The results of this study may help in developing approaches to a targeted increase in flower size and seed productivity. Full article

Real-time monitoring of lithium-ion capacitors (LICs) is crucial for ensuring reliability and predictive maintenance in dynamic applications such as electric transportation. However, traditional electrochemical impedance spectroscopy (EIS) techniques are complex and costly for onboard diagnostics due to their reliance on external excitation signals and dedicated hardware. Therefore, this paper presents an innovative framework for online state of health (SOH) estimation that bypasses these limitations by utilizing fast Fourier transform (FFT)-based passive impedance extraction directly from operational current and voltage signals. From experimental data, the equivalent circuit model (ECM) is developed, as well as its parameters, such as ohmic resistance, charge-transfer resistance, and Warburg diffusion. These parameters are identified through the extraction of impedance points in the low frequency region through FFT and the series resistance point using ohmic measurement, then performing a periodic curve fitting to these points. These curve fittings provide extracted ECM parameters. These parameters are used with a trained model to estimate the SOH of the monitored cell and are updated online. The proposed method was experimentally validated on five LIC cells aged under various C-rates (1C, 4C, 7C) and temperatures (35 °C, 40 °C, 50 °C), showing consistent impedance evolution with capacity fade. Validation of the utilized machine learning models, such as Polynomial Regression (PR), principal components analysis (PCA), and random forest (RF) regression, achieved SOH prediction errors as low as 2.23% compared to experimental results. The developed framework is particularly suitable for applications such as flash-charged electric buses but is broadly applicable across other energy storage systems as well. This advanced method enables real-time diagnostics without hardware modification, offering significant potential for integration into existing battery management systems (BMSs). Full article