Search Results (5,760)

Volatile amphiphiles and surfactant mixtures have gained wide applications in diverse areas of industry, cosmetics, and medicine. The surface tension isotherms, measured at different solute ratios, and data processing, using appropriate theoretical models, provide quantitative information on their bulk and interfacial properties. Here, this approach is applied for mixtures of volatile amphiphile (benzyl acetate, linalool, geraniol, menthol, citronellol) and sodium dodecyl sulfate (SDS). All surface tension isotherms are described by the van der Waals model for a two-component adsorption layer, taking into account the counterion binding in the Stern layer, by varying only one adjustable parameter (interfacial pair interaction energy between adsorbed molecules). Knowing the parameters of the model, we computed various properties of the adsorption layers (adsorptions of different components, occupancy of the Stern layer, and interfacial electrostatic potential). The experimental aqueous solubilities of mixtures are fitted using the regular solution theory to obtain the pair bulk interaction parameter. The mixing of SDS and: (i) benzyl acetate and citronellol is antagonistic; (ii) linalool and geraniol is synergistic; and (iii) menthol is ideal. The reported properties of the volatile amphiphiles and SDS mixtures could be of interest for increasing the range of their applicability in practice. Full article

The primary objective of this research is to engineer a high-performance, sustainable material for aquatic remediation by repurposing low-cost biogenic silica into a selective hydrophobic adsorbent. By integrating the natural hierarchical porosity of Diatomaceous Earth (DE) with a tailored silanization strategy, this work aims to provide a scalable and eco-friendly solution for the efficient encapsulation and mechanical recovery of hydrocarbons from contaminated water. To overcome the inherent hydrophilicity of DE, a two-step functionalization process was developed, involving alkaline activation followed by the covalent grafting of hexadecyltrimethoxysilane (C16) in different concentrations. The resulting C16@DE hybrid materials underwent a dramatic surface energy transformation, shifting from hydrophilic behavior to robust hydrophobicity, with static contact angles reaching up to 134.8°. Optical analysis revealed a unique remediation mechanism: while pristine DE disperses homogeneously in the aqueous phase, functionalized C16@DE spontaneously organizes into discrete pellets upon contact with diesel, effectively encapsulating the fuel. Quantitative UV/vis spectrophotometry confirmed that these composites sequester approximately 55–56% of the diesel phase. Together, these results demonstrate that C16@DE materials couple intrinsic biosilica porosity with tailored hydrophobicity to achieve efficient hydrocarbon capture. By combining the natural hierarchical porosity of diatoms with engineered surface selectivity, this research positions functionalized DE as a scalable, low-cost, and eco-friendly promising solution for marine oil spill recovery and industrial wastewater treatment. Full article

This study explored the continuous monitoring of hydrogen-induced cracking (HIC) in high-strength steel tension wires used in metal-based flexible pipes, exposed to a H₂S-saturated aqueous environment, using acoustic emission (AE) techniques. Armor wire samples were subjected to sour conditions under controlled environments for 24 and 96 h. To reinforce and validate the AE findings, a comprehensive characterization was performed, including X-ray microtomography, optical microscopy, and scanning electron microscopy. The experimental results demonstrated that AE techniques effectively monitored the evolution of HIC damage in the armor wire samples, enabling the identification of distinct damage stages and cracking phenomena. These findings confirm that AE can serve as a valuable complementary tool during HIC testing, optimizing test duration and providing insights into the kinetics of the cracking process. Full article

The persistence of azo dyes in industrial effluents poses significant environmental risks; therefore, there is a need to develop effective adsorbents. This study investigates the efficiency of a Cu₂O/CuO nanocomposite as an adsorbent for the removal of a model dye, methyl orange (MO), from aqueous solutions. The material was characterized by XRD, SEM and BET analyses, revealing a dominant Cu₂O phase (96 wt%) with CuO fractions, and an average particle size of ~18 nm paired with a specific surface area of 19.54 m² g⁻¹. FTIR and TOC assays revealed the adsorption and degradation of MO by action of the nanocomposite. Operational parameters such as adsorbent dosage, initial dye concentration, pH, and the point of zero charge (PZC) were investigated. Under the optimized conditions, the nanocomposite achieved a dye removal efficiency of 97.0%. The kinetic results showed a strong correlation with the pseudo-second-order model. Furthermore, isotherm analysis revealed that the adsorption process is best described by the Langmuir–Freundlich model, demonstrating an outstanding maximum theoretical adsorption capacity (q_max) of 254.76 mg g⁻¹, which closely aligns with the experimental value (249.48 mg g⁻¹). The findings demonstrated that the synthesized Cu₂O/CuO nanocomposite acts as an efficient and promising adsorbent for the remediation of dye-contaminated waters. Full article

Nonfat dry milk (NFDM) powder was produced by spray drying a pulsed electric field (PEF)-treated solution of 48% (m/m) evaporated skim milk (ESM) that was treated with a field strength of 20 kV/cm and specific energy of 15 kJ/L at 150 L/h. PEF treatment induced reduction to particle size for whey proteins by 8.4% and casein micelles by 11.1% and increased conductivity by 10.6%. The PEF-treated ESM solution was less viscous than the non-PEF control (14.5% lower) and sedimentation was reduced by 40%. Increases to the tapped density (1.9%), solubility (4.7%), and emulsification stability (60%) of the NFDM were observed after PEF treatment. Evaluation of protein structure indicated no modification to the secondary structure, while minor changes to the tertiary structure were observed with increased fluorescence intensity and decreased transition temperatures. The reduction in casein micelle size for the PEF-treated ESM may be associated with the movement of minerals to the aqueous solvent. This study is the first to apply PEF technology to a highly concentrated ESM solution using a continuous flow commercial PEF system. The results of this study suggest that PEF technology may be beneficial to improving the dairy processing efficiency of ESM and product quality for NFDM. Full article

Six 1,4-disubstituted pyrazoles linked to a benzenesulfonamide and a benzodioxane unit have been synthesized through a copper(I)-catalyzed formal [3+2] cycloaddition (32CA) reaction of alkynes with 3-arylsydnones. The Cu-catalyzed sydnone–alkyne cycloaddition (CuSAC) procedure has been optimized to promote the formation of the pyrazole ring and to deliver in three steps the six target compounds 5a–f, fully characterized by ¹H/¹³C-NMR and mass spectrometry (EIMS). Ten solvent conditions were evaluated. The reaction proceeded most efficiently in the presence of copper(II) sulfate pentahydrate in aqueous t-butanol in the presence sodium acetate, to reach a yield of 96%. The mechanism of the Cu(I)-catalyzed reaction has been studied within the Molecular Electron Density Theory (MEDT). This rection is a domino process that consists in a Cu(I)-catalyzed formal [3+2] cycloaddition followed of an extrusion of CO₂ yielding the final pyrazole. The capacity of heterocyclic compounds 5a–f to interact with human cyclophilin A (Cyp A), which is a host cofactor for hepatitis C virus (HCV) and human immunodeficiency virus 1 (HIV-1), and with the HIV-1 protein gp120-CD4 was evaluated using molecular docking. Compounds 5a,b,d,f showed a satisfactory protein binding capacity. The physicochemical and metabolic properties of the compounds were also evaluated in silico. These predictions provide important information to guide future design in this series of potential antiviral agents. Full article

The origin of life is commonly discussed within two competing conceptual frameworks: the metabolism-first and information-first hypotheses. While each emphasizes a different defining property of early life, modern biochemistry reveals a fundamental interdependence between metabolic processes and genetic information transfer, leading to a persistent chicken-and-egg problem. In this study, we investigate a prebiotically plausible reaction system that enables the concurrent formation of molecular precursors associated with both frameworks. Under simulated Hadean hydrothermal conditions, acetylene, ammonia, cyanide, and carbon monoxide were reacted in aqueous solution in the presence of transition metal sulfides. Using gas chromatography–mass spectrometry combined with stable isotope labeling, we demonstrate the simultaneous formation of the nucleobase uracil and the amino acids alanine and aspartic acid. Isotopic incorporation patterns allow reconstruction of the underlying reaction pathways and confirm the contribution of all starting materials to product formation. While amino acids are produced continuously over the observed period in significantly higher yields than uracil, uracil formation exhibits a pronounced time-dependent maximum after three days. Variations in pH, reaction time, and metal sulfide catalysts modulate product yields but do not prevent the parallel emergence of both molecular classes. These findings support a scenario in which proto-metabolic chemistry and molecular precursors of genetic information could have arisen simultaneously within a shared geochemical setting. The results provide experimental support for a coupled origin of metabolism and transcriptional building blocks, offering a potential resolution to the dichotomy between metabolism-first and information-first models of early life. Full article

Background/Objectives: Gastro-resistant multiparticulate systems are designed to protect drugs in acidic environments and to ensure intestinal release. In practice, the method of administration may need to be modified: pellet-containing capsules opened or tablets halved for patients with swallowing difficulties, yet the type of liquid used for administration is often not specified. This study examined the stability of gastro-resistant coated pellets after exposure to various aqueous media prior to ingestion. Methods: To evaluate administration instructions, 103 Summaries of Product Characteristics of gastro-resistant products were reviewed. Pellets were produced using a bottom-spray fluidized bed process and coated with Eudragit L 30 D-55. Dissolution testing in pH 1.2 medium was performed after pre-soaking the pellets for 5, 15, and 30 min in beverages with various pH and conductivity. Drug release was measured by UV-VIS method, and morphological changes were assessed by image analysis. Marketed gastro-resistant products were also examined visually. Results: SmPC review revealed that the beverage for intake was frequently unspecified. Among the tested beverages differences in pH and conductivity were observed. Alkaline medicinal mineral waters induced increased and time-dependent premature drug release compared to tap and filtered water. Image analysis indicated a reduction in surface area after exposure to alkaline media. Conclusions: Contact with non-specified aqueous media before swallowing may weaken the protective function of gastro-resistant films. More explicit recommendations on suitable administration manipulation and media may improve therapeutic consistency. Full article

Agroindustrial residues represent an abundant and underutilized source of carbon-rich materials for environmental remediation. In this study, annatto processing waste (Bixa orellana), a largely unexplored lignocellulosic by-product generated during pigment extraction, was converted into hydrochar via hydrothermal carbonization at 200 °C for 3 h. The resulting hydrochar (HC-AW) exhibited a predominantly amorphous carbon structure with retained oxygen-containing surface functionalities, and a solid yield of 44%, indicating efficient biomass conversion under subcritical conditions. Adsorption performance toward tetracycline was evaluated through pH-dependent experiments, kinetic modeling, equilibrium isotherms, and thermodynamic analysis. Maximum adsorption occurred under near-neutral conditions (pH ≈ 7), consistent with the interplay between tetracycline speciation and the hydrochar surface charge (pH_PZC ≈ 6.3), highlighting its potential applicability under realistic water treatment conditions without pH adjustment. Kinetic data were well described by the pseudo-second-order model, while equilibrium results were best fitted by the Langmuir model, with a maximum adsorption capacity of 14.94 mg g⁻¹ at 30 °C. Thermodynamic analysis indicated a spontaneous and slightly endothermic adsorption process. Overall, the results highlight the potential of annatto-derived hydrochar as a low-cost adsorbent and provide insight into the relationship between surface properties and adsorption behavior governing antibiotic removal from aqueous systems. Full article

Aqueous proton batteries (APBs) are promising for safe energy storage, yet their cathode development is hindered by the lack of organic materials with reversible redox activity and long cycling stability in acidic media. Herein, an acceptor-enriched PNZ–TCNQ organic charge-transfer complex was constructed by increasing the TCNQ ratio. Spectroscopic results are consistent with strengthened donor–acceptor interactions and altered local electronic environments. The PNZ–TCNQ cathode delivered ~190 mAh g⁻¹ at 0.6 A g⁻¹ and retained ~85% capacity after 10,000 cycles at 5 A g⁻¹ in acidic three-electrode tests. Kinetic analyses revealed mixed charge storage contributions from pseudocapacitive and diffusion-influenced processes. In situ/ex situ characterizations confirmed reversible redox evolution of the donor–acceptor complex with preserved molecular backbones. This work shows that tuning intermolecular charge-transfer interactions is an effective strategy for improving the cycling stability of organic cathodes in acidic aqueous electrolytes. Full article

This report investigates the capacity of crystal violet (CV) uptake from aqueous solutions by a sulfonated gel (Sulfo-Gel) made via free radical polymerization of acrylamide and sulfonic monomer (3-Allyloxy-2-hydroxy-1-propanesulfonic acid sodium salt). CV uptake was examined through a batch technique, assessing the effects of various conditions, including uptake time, solution pH, gel dose, initial concentration of dye, and temperature. Results showed that the hydrogel adsorbent removed 74.88% of the CV dye at a gel dose of 500 mg/L in a neutral medium at initial CV concentration of 30 mg/L and contact time 100 min. The adsorption kinetics were best depicted by nonlinear fitting of pseudo-first-order model. Additionally, adsorption isotherms were analyzed using nonlinear fitting of the Langmuir, Freundlich, Temkin, and Dubinin–Radushkevich models, with the data fitting the Temkin model most effectively. Thermodynamic studies signified the exothermic nature of the adsorption process and its spontaneity. Full article

Glass ionomer cements (GICs) are considered functionally biomimetic as they participate in ion-exchange processes that partially resemble the behavior of natural enamel and dentin, chemically bond to dental hard tissues, and release fluoride. While GICs are designed to interact with aqueous oral environments, their exposure to dietary beverages may affect their esthetic stability and water-related behavior within the oral environment. For biomimetic restorative materials to perform successfully in the oral environment, they must maintain not only bioactive properties but also esthetic stability and resistance to water-related degradation during exposure to dietary beverages. This study evaluated beverage-induced color changes, water sorption, and water solubility of six GICs following their immersion in coffee, tea, berry juice, cola, and distilled water (n = 5 per material per solution). Color measurements were recorded at baseline and after 2, 4, 6, and 8 weeks using a spectrophotometer, and color change (ΔE) values were calculated using the CIE L*a*b* system. Specimen mass was measured at baseline, after 8 weeks of immersion and then after 4 weeks of desiccation. Data were analyzed using repeated-measures Analysis of Variance (ANOVA) and Fisher’s least significant difference post hoc tests (α = 0.05). The results showed time, material, and solution significantly affected ΔE (p < 0.001). Tea produced the greatest discoloration overall, followed by coffee. ChemFil exhibited the greatest staining susceptibility, while Fuji II showed the lowest staining susceptibility. Water sorption and solubility were material- and solution-dependent. Clinically relevant discoloration of GICs was found when immersed in common beverages over time, with tea showing the strongest staining effect. These findings indicate that although GICs exhibit biomimetic characteristics through their interaction with tooth structures and aqueous environments, their long-term esthetic stability and resistance to environmental challenges should also be considered when selecting restorative materials for clinically visible areas. Full article

Elevated temperatures are frequently encountered in numerous occupational settings such as iron and steel foundries, non-ferrous metal foundries, brick and ceramic manufacturing plants, glass production facilities, rubber factories, electrical power plants, bakeries, laundries, chemical processing sites, mining operations, smelting plants, and steam tunnels. Employees working in these environments are at risk of developing various health issues and injuries, including ocular complications, due to prolonged exposure to heat and the physical demands of handling heavy materials. This study focuses on examining the pressure within the eye’s anterior chamber, referred to as Intraocular Pressure (IOP), and its association with the cornea’s biomechanical characteristics, with particular attention to corneal temperature. Our methodology is grounded in the principles of the first law of thermodynamics. The findings reveal a link between the temperature of the eye’s anterior chamber and the biomechanical behaviour of the cornea. Specifically, IOP serves as an indicator of the cornea’s elasticity and its optical properties as influenced by temperature variations. We investigated how the cornea’s elastic energy, or the work it performs, varies with temperature changes. The results show that an increase in temperature corresponds to a reduction in the work exerted by the cornea. The corneal temperature is affected by both the ambient environment and the temperature of the aqueous humour within the anterior chamber. This indicates a relationship between the mechanical work done by the cornea and the pressure exerted by the fluid in the eye’s front segment. Furthermore, our study identified a correlation between corneal thickness and IOP, which our modelling approach successfully quantifies. Utilizing the first law of thermodynamics, we calculated the work performed by the anterior chamber against the cornea’s internal surface. Temperature fluctuations influence the secretion, drainage, and flow characteristics of the aqueous humour, thereby impacting IOP and associated ocular conditions. These insights are valuable for devising strategies aimed at preventing eye injuries among workers exposed to high-temperature environments. Full article

Water contamination by synthetic dyes such as malachite green (MG) remains a significant environmental and public health challenge due to their high toxicity, chemical stability, and resistance to biodegradation. In this study, a CaO-CuFe₂O₄ composite was synthesized through a sustainable route using eggshells and orange peel as agro-industrial waste precursors. Comprehensive structural, spectroscopic and microscopic analyses confirmed the coexistence of a predominant CaO-based phase with spinel CuFe₂O₄, together with nanometric features, satisfactory elemental dispersion and practical magnetic recoverability. Under the experimental conditions employed, the composite exhibited high adsorption performance towards MG, reaching an equilibrium capacity of 2288.4 mg g⁻¹ and 99.98% decolorization within 60 min. The kinetics were better described by the pseudo-second-order model, while the equilibrium behavior was more satisfactorily fitted by the Langmuir isotherm than by the Freundlich model. Thermodynamic analysis indicated that the adsorption process was favorable over the temperature range studied and became more pronounced at higher temperature. The results suggest that the adsorption behavior arises from the combined influence of surface chemistry, calcium-derived basic sites, ferrite-associated metal centers and interfacial accessibility, rather than from surface area alone. In addition, the material could be readily separated from aqueous solution using an external magnetic field, highlighting its practical post-treatment recoverability. Overall, this work demonstrates a viable waste valorization strategy for the development of a magnetically recoverable CaO-CuFe₂O₄ adsorbent for cationic dye removal. Beyond the specific case of MG, the study underscores the potential of agro-waste-derived hybrid oxides as application-relevant materials for water remediation. Full article

Perylene bisimide derivatives are typical n-type semiconductors as well as redox-active materials. However, it has been difficult to produce thin films by solution processes because of their low solubilities in organic solvents. Perylene bisimide derivatives bearing oligosiloxane moieties exhibit columnar phases over wide temperature ranges, including room temperature and high solubilities in organic solvents. The columnar phases are stabilized by nanosegregation between crystal-like one-dimensional π-stacks and liquid-like mantle consisting of oligosiloxane moieties. The electron mobility at room temperature exceeded 0.1 cm²V⁻¹s⁻¹ in the ordered columnar phases of perylene bisimide derivatives bearing four disiloxane chains. Uniaxially aligned thin films of the perylene bisimide derivatives bearing oligosiloxane moieties could be produced by a spin-coating method. The spin-coated films of the perylene bisimide derivatives bearing cyclotetrasiloxane rings could be insolubilized via in situ ring-opening polymerization by the exposure of the thin films to trifluoromethanesulfonic acid vapors. Uniaxially aligned thin films of perylene bisimide derivatives bearing an ethylene oxide chain as well as cyclotetrasiloxane rings could be doped in an aqueous solution of sodium dithionate, resulting in an anisotropic electrical conductivity. Polymerized thin films of perylene bisimide derivatives bearing a crown ether ring exhibited electrochromism in electrolyte solutions. These compounds formed 1:1 complexes with lithium triflate, exhibiting columnar phases at room temperature. The nanostructures of the complexes were stabilized by the electrostatic interaction between cationic crown-metal units and triflate anions. Full article