Search Results (13,072)

Sophorolipids (SLs) constitute a group of unique biosurfactants in light of their unique properties, among which their physicochemical characteristics and antimicrobial activity stand out. SLs can exist mainly in acidic and lactonic forms, both of which display inhibitory activity. This study explores the interaction of non-acetylated acidic SL with bovine serum albumin (BSA). SL significantly enhances BSA’s thermal stability, increasing its midpoint unfolding temperature from 61.9 °C to approximately 76.0 °C and ΔH from 727 to 1054 kJ mol⁻¹ at high concentrations, indicating cooperative binding. Fourier-Transform Infrared Spectroscopy (FTIR) analysis confirms SL’s protective effect against thermal unfolding, enabling BSA to maintain its helical structure at 70 °C, distinguishing it from other surfactants that cause denaturation. Furthermore, SL fundamentally alters the sequence of thermal unfolding events; β-aggregation precedes helical domain unfolding, suggesting protective binding to BSA’s helical regions. Computational docking reveals high-affinity binding (Kd = 14.5 μM). Uniquely, SL binds between BSA domains IB and IIIA, establishing hydrophobic interactions, salt bridges, and hydrogen bonds, thus stabilizing the protein’s 3D structure. This distinct binding site is attributed to SL’s amphipathic character. This work deepens the understanding of the molecular characteristics of SL–protein interactions and contributes to improving the general knowledge of this outstanding biosurfactant. Full article

It is known that approximately 8% of atmospheric carbon dioxide (CO₂) emissions originate from cement production. Consequently, there is ongoing rapid research into environmentally friendly and alternative materials that could substitute for cement. Olivine [(Mg, Fe)₂SiO₄] is an abundant mineral in the Earth’s crust that facilitates CO₂ sequestration due to its high solubility. This study investigates the effects of hydration mechanisms in olivine-substituted cement mortars on their compressive strength, microstructural characteristics, and physical properties. For this purpose, standard cement mortars were produced using CEM IV 32.5 N-type cement with olivine substitution rates of 0%, 10%, and 20%. The compressive strength of the specimens was initially determined at 7, 28, and 90 days. Subsequently, the hydration mechanisms at 7, 28, and 90 days were characterized using X-ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FT-IR), Differential Thermal Analysis/Thermogravimetric Analysis (DTA/TG), and Scanning Electron Microscopy-Energy Dispersive Spectroscopy (SEM-EDS). The results demonstrated that the 10% substitution rate complies with the BS EN 196-1 standard, and olivine can be substituted for CEM IV type cement up to 10% without requiring calcination. Full article

Halloumi cheese, a traditional Cypriot dairy product with Protected Designation of Origin (PDO) status, is renowned for its unique texture and high melting point. PDO certification is crucial for Halloumi cheese as it ensures the product’s authenticity, protects its traditional production methods and geographical origin, and safeguards consumers and producers against fraud and mislabeling. However, concerns over adulteration, particularly through the addition of skim milk powder, pose challenges to its authenticity and quality control. This study is the first to analyze Halloumi cheese using Brunauer–Emmett–Teller (BET) analysis and Fourier Transform Infrared (FTIR) spectroscopy, providing a novel approach to assessing its composition and authenticity. Furthermore, it marks the first time Halloumi samples have been examined in the context of PDO certification. Alongside PDO-certified Halloumi, two additional sample sets were produced following PDO specifications for moisture, fat, and salt content, with the controlled incorporation of skim milk powder as an adulterant at concentrations of 1% and 5%. Principal component analysis (PCA) was employed to visualize and interpret the spectral data, revealing promising results. Chemometric analysis showed that the specific surface area from BET measurements and the FTIR spectral subregion between 1650 and 1100 cm⁻¹ were key factors, and they were retained for model construction. These findings could play a crucial role in establishing official food fraud detection methodologies, particularly for the Cyprus and EU markets. While this study serves as an initial investigation, additional samples will be tested in future studies to validate these preliminary results and to assess the potential of applying these techniques in real-world food fraud detection scenarios. Full article

This study developed a novel adsorbent for Cr (VI) removal from wastewater by grafting N-[(dimethylamino)methylene]thiourea (TUFA) onto lignin. The resulting TUFA-functionalized lignin adsorbent AL was comprehensively characterized using scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), nuclear magnetic resonance (NMR), and X-ray photoelectron spectroscopy (XPS). Batch adsorption experiments systematically evaluated the influence of solution pH, contact time, temperature, initial Cr (VI) concentration, and adsorbent dosage. AL exhibited high adsorption capacity (593.9 mg g⁻¹ at 40 °C), attributed to its abundant nitrogen and sulfur-containing functional groups. Kinetic analysis revealed that the adsorption process followed pseudo-second-order kinetics. Equilibrium isotherm data were best described by the Langmuir model, indicating predominant monolayer chemisorption. Thermodynamic parameters demonstrated that Cr (VI) adsorption onto AL is spontaneous, endothermic, and entropy-driven. The adsorption mechanism involves membrane diffusion and intra-particle diffusion processes. This work successfully synthesized a stable, effective, and low-cost adsorbent (AL) using an amine agent incorporating both nitrogen and sulfur functional groups, offering a promising approach for treating Cr (VI)-contaminated wastewater. Full article

The increasing demand for sustainable alternatives to synthetic agrochemicals underscores the need for novel, naturally derived plant growth regulators (PGRs) with high specificity and minimal environmental impact. In this study, we propose agavenin (AG), a steroidal saponin from Agave species, as a promising candidate and evaluate its potential role in plant growth regulation through a comprehensive in silico approach. Using molecular docking, molecular dynamics simulations, ADME profiling, and FTIR spectroscopy, we analyzed the interaction of AG with three key protein receptors (KPRs) that regulate major hormonal pathways: GA3Ox2 (gibberellin), IAA7 (auxin), and BRI1 (brassinosteroid). AG showed strong and stable binding to GA3Ox2 and IAA7, with affinities comparable to their endogenous ligands, while exhibiting low interaction with BRI1—suggesting receptor selectivity. Molecular dynamics confirmed the stability of AG–GA3Ox2 and AG–IAA7 complexes over 100 ns, and ADME profiling highlighted favorable properties for bioavailability and transport. Collectively, these findings indicate that AG could function as a selective, receptor-targeted modulator of gibberellin and auxin signaling pathways. Beyond demonstrating the molecular basis of AG’s bioactivity, this work establishes a computational foundation for its future experimental validation and potential development as a sustainable, naturally derived growth regulator for plant biotechnology and agriculture. Full article

Sodium chloride (NaCl) was essential for making mianpi, a traditional Chinese wheat starch gel food. The production process included wheat flour/starch slurry preparation, steaming, cooling, and cutting. This study investigated how NaCl affected both the slurry’s properties and the quality of mianpi using three formulations: wheat flour (F100), a 50:50 (w/w) wheat flour–starch mix (F50), and wheat starch (F0). Our findings demonstrated that NaCl significantly altered the slurry rheology, pasting behavior, texture, and starch ordered structures. It notably reduced the slurry apparent viscosity, while it showed a divergent effect on its pasting properties. Regarding product quality, NaCl induced a measurable alteration in L*, a*, and b* values of mianpi, though visually imperceptible. F100 mianpi maintained texture except for when adding 2% NaCl, which reduced hardness. NaCl increased tensile strength (excluding F0). However, it caused irregular texture changes in F50 and F0 mianpi. Furthermore, NaCl modulated viscoelastic properties of mianpi products, as evidenced by reductions in storage and loss modulus. FT-IR showed NaCl disrupted starch short-range order in F100/F0 but improved it in F50, though Raman spectroscopy (480 cm⁻¹) did not detect this shift. Gluten protein secondary structure remained unaffected across all formulations. These results guide NaCl–starch–flour formulations in starch-gel-based foods. Full article

The efficient resource utilization of industrial solid wastes, such as ground granulated blast-furnace slag (GGBS) and coal gangue (CG), is essential for sustainable development. However, their activation commonly depends on expensive and corrosive chemical alkalis. This study proposes a solution by developing a fully waste-based cementitious material using calcium carbide slag (CS), another industrial residue, as an eco-friendly alkaline activator for the GGBS-CG system. The influence of CS dosage (0–20 wt%) on hydration evolution and mechanical properties was examined using uniaxial compression testing, X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM). The results indicated that a CS dosage of 10 wt% yielded the highest compressive strength, reaching 10.13 MPa—a 16.5% improvement compared to the 20 wt% group. This enhancement is ascribed to the formation of hydrotalcite (HT) and calcium silicate hydrate (C-(A)-S-H) gel, which densify the microstructure. In contrast, higher CS contents led to a passivation effect that restrained further reaction. This work offers a practical and theoretical basis for the development of low-carbon, multi-waste cementitious materials and presents a promising strategy for large-scale valorization of industrial solid wastes. Full article

This paper presents the development of handmade paper from fique residues, evaluating its technical and environmental viability through a scientific approach aimed at supporting low-income rural communities. The residues were characterized to assess their suitability for papermaking, with fiber crystallinity and chemical structure analyzed using X-ray diffraction (XRD) and ATR-FTIR spectroscopy. Pulps were produced from fique fibers and a 30:70 fique fiber–bagasse blend using a chemical-free mechanical pulping process, designed for easy implementation in rural settings. The effects of dyeing on pulp performance were also examined, and environmental impacts were assessed through a Life-Cycle Assessment (LCA). The average fiber length, diameter, and lumen of fique fibers were 1.83 mm, 26.5 μm, and 17.4 μm, respectively. Handsheets from fique pulp achieved a tensile index of 13.0 N·m/g and a burst index of 1.42 kPa·m²/g, while the fique fiber–bagasse blend reached 11.09 N·m/g and 1.05 kPa·m²/g. The corresponding sheet densities were 0.316 and 0.380 g/cm³. The dyeing process led to a reduction in the mechanical strength of the handmade paper. Environmental analysis indicated that fique tow fiber has a more favorable impact profile than other non-wood alternatives, such as aquatic weed fiber. Compared to results from similar studies, fique demonstrates strong potential as a high-quality, sustainable raw material for artisanal papermaking. These findings support its application in decentralized, eco-friendly production systems, contributing to rural development and circular economy strategies. Full article

Thermal oxidative aging failure of high-temperature vulcanized silicone rubber (HTV) in high-voltage insulators is the core hidden danger of power grid security. In this study, terahertz time domain spectroscopy (THz-TDS) and attenuated total reflection infrared spectroscopy (ATR-FTIR) were combined to reveal the quantitative structure–activity relationship between dielectric response and chemical group evolution of HTV during accelerated aging at 200 °C for 80 days. In this study, HTV flat samples were made in the laboratory, and the dielectric spectrum of HTV in the range of 0.1 THz to 0.4 THz was extracted by a terahertz time–domain spectrum platform. ATR-FTIR was used to analyze the functional group change trend of HTV during aging, and the three-stage evolution of the dielectric real part (0.16 THz), the dynamics of the carbonyl group, the monotonic rise of the dielectric imaginary part (0.17 THz), and the linear response of silicon-oxygen bond breaking were obtained by combining the double Debye relaxation theory. Finally, three aging stages of HTV were characterized by dielectric loss angle data. The model can warn about the critical point of early oxidation and main chain fracture and identify the risk of insulation failure in advance compared with traditional methods. This study provides a multi-scale physical basis for nondestructive life assessment in a silicon rubber insulator. Full article

Plant gums have long served as essential binding media in polychrome cultural heritage, contributing to pigment adhesion, surface cohesion, and long-term stability. This review evaluates recent advances in analytical technologies, including FTIR, Raman spectroscopy, GC-MS, LC-MS/MS, MALDI-TOF MS, hyperspectral imaging, and immunological assays, for the identification of gums such as gum arabic, peach gum, and tragacanth in diverse cultural contexts. Drawing on case studies from 19th-century watercolours, ancient Egyptian coffins, and Maya murals, the paper demonstrates how these methods enable precise chemical characterization even in complex, aged, and mineral-rich matrices. Such information directly aids conservators in selecting compatible restoration materials, tailoring treatment protocols, and assessing deterioration mechanisms. Persistent challenges remain, including gum degradation, spectral interference from pigments and restoration materials, sample heterogeneity, and limited reference libraries, particularly for non-European species. Future research directions emphasize multi-modal, non-invasive workflows that integrate hyperspectral imaging with spectroscopic and chromatographic methods, drone-assisted micro-Raman for inaccessible surfaces, machine learning-assisted spectral databases, and bio-inspired adhesives replicating historical rheology. By linking molecular identification to conservation decision-making, plant gum analysis not only deepens our understanding of historical material practices but also strengthens the scientific basis for sustainable heritage preservation strategies. Full article

This study aims to develop high-performance biocomposites for structural applications using kenaf, bagasse, hemp, and softwood fibers bonded with phenol-formaldehyde (PF) and phenol-urea-formaldehyde (PUF) adhesives, commonly used in particleboard manufacturing. A simple, low-cost fiber treatment was applied by adjusting the fiber pH to 11 and 13 using a 33% NaOH solution, following standard protocols to enhance fiber–adhesive interaction. The effects of alkaline treatment on the chemical structure of bagasse, kenaf, and hemp fibers were investigated using Fourier Transform Infrared Spectroscopy (FTIR) and correlated with composite mechanical performance. PF and PUF were applied at 13% (w/w), while polymeric diphenylmethane diisocyanate (pMDI) at 5% (w/w) served as a control for untreated fibers. The fabricated panels were evaluated for mechanical properties; modulus of elasticity (MOE), modulus of rupture (MOR), and internal bond strength (IB), and physical properties such as thickness swelling (TS) and water absorption (WA) after 24 h of immersion. FTIR analysis revealed that treatment at pH 11 increased the intensity of O–H, C–O–C, and C–O bands and led to the disappearance of the C=O band (~1700 cm⁻¹) in all fibers. Bagasse treated at pH 11 showed the most significant spectral changes and the highest IB values with both PF and PUF adhesives, followed by kenaf at pH 13, exceeding EN 312:6 (2010) standards for heavy-duty load-bearing panels in dry conditions. The highest MOE and MOR values were achieved with kenaf at pH 11, meeting EN 312:4 (2010) requirements, followed by bagasse, while softwood and hemp performed less favorably. In terms of thickness swelling, bagasse consistently outperformed all other fibers across pH levels and adhesives, followed by Kenaf and Hemp, surpassing even pMDI-based composites. These results suggest that high-pH treatment enhances the reactivity of PF and PUF adhesives by increasing the nucleophilic character of phenolic rings during polymerization. The performance differences among fibers are also attributed to variations in the aspect ratio and intrinsic structural properties influencing fiber–adhesive interactions under alkaline conditions. Overall, kenaf and bagasse fibers emerge as promising, sustainable alternatives to industrial softwood particles for structural particleboard production. PF and PUF adhesives offer cost-effective and less toxic options compared to pMDI, supporting their use in eco-friendly panel manufacturing. FTIR spectroscopy proved to be a powerful method for identifying structural changes caused by alkaline treatment and provided valuable insights into the resulting mechanical and physical performance of the biocomposites. Full article

This study explored the synthesis and characterization of pectin-based composites containing encapsulated propolis and sea buckthorn oil. Both propolis and sea buckthorn oil are well known for their antioxidant and antimicrobial properties. To mitigate their sensitivity to environmental degradation, these compounds were encapsulated within a pectin matrix. The composites were prepared using an emulsification technique and subsequently for their physicochemical properties via scanning electron microscopy (SEM), ultraviolet–visible spectroscopy (UV-Vis), Fourier-transform infrared spectroscopy (FTIR), and differential scanning calorimetry (DSC), as well as color and mechanical testing. The results showed that freeze-dried samples exhibited heterogeneous, bubble-like structures containing nanocapsules (800–2000 nm), whereas for the film samples, the capsules were visibly embedded within the matrix. The study shows that this three-component system exhibits synergistic potential. Encapsulation significantly improved the UV barrier properties and the antioxidant activity of the nanocomposites, which demonstrated greater antioxidant capacity. Microbiological assays revealed that the pectin-based composites containing encapsulated propolis and sea buckthorn oil exhibited strong antibacterial activity, particularly against Gram-positive bacteria such as Streptococcus and Staphylococcus spp. The composites also demonstrated hydrophobic surface characteristics and reduced crystallinity, which correlates with their potential for controlled release. These results underscore the applicability of pectin–propolis–sea buckthorn oil composites as effective natural preservatives or functional ingredients in food systems, due to their high antioxidant and antimicrobial efficacy. Full article

Excessive phosphorus emissions are a significant driver of severe eutrophication in water bodies, and developing an efficient and cost-effective adsorbent for phosphorus removal is imperative. In this study, a Na-type zeolite was synthesized from coal gangue sourced from an open-pit mine in Xinjiang province, China. The synthesis process involved drying, crushing, alkali activation, aging, hydrothermal crystallization, and Na⁺ ion exchange. Orthogonal design identified the optimal synthesis parameters: an alkali-to-ash ratio of 1:1, aging at 20 °C for 12 h, and crystallization at 130 °C for 12 h. Aging time exerted the greatest influence on the phosphate removal efficiency. The optimized zeolite exhibited excellent phosphate adsorption performance, achieving a removal efficiency of up to 96% and a capacity of 16 mg/g. The adsorption kinetics followed both pseudo-first-order and pseudo-second-order models, indicating processes governed by combined physical and chemical mechanisms. Isotherm data fitting with Freundlich and Langmuir models suggested the presence of both homogeneous and heterogeneous active sites. Thermodynamic studies confirmed a spontaneous and endothermic process, increasingly favorable at higher temperatures. Characterizations via scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray fluorescence (XRF) spectroscopy, and Fourier transform infrared (FTIR) spectroscopy confirmed the formation of Na-type zeolite and revealed structural and compositional changes following phosphate adsorption. Aluminum and calcium binding played key roles in the chemical adsorption mechanisms. This work not only offers a high-efficiency, low-cost solution for phosphorus removal from wastewater but also provides a sustainable pathway for the valorization of coal gangue in the Zhundong area of Xinjiang, China. Full article

In this study the influence of the geological formation environment on the physicochemical properties of two natural sepiolites, as collected, was investigated. The samples analyzed were a lacustrine-derived sample from Tolsa, Spain (ST), and a hydrothermal-derived sample from La Adela, Argentine (SA). Comprehensive characterization was carried out using chemical analysis (XRF), X-ray diffraction (XRD), thermogravimetric analysis (TGA), Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and evaluations of hydrophobicity/hydrophilicity behavior. The results indicate that the ST sample exhibits a higher SiO₂/MgO ratio and contains amorphous silica impurities, while the SA sample shows a composition more closely aligned with the theoretical stoichiometry of sepiolite. Furthermore, the SA sample demonstrates greater crystallinity compared to the ST sample. Morphological analysis revealed that ST consists of compact, aggregated fibrous structures, while SA is composed of disaggregated, needle-like fibers with high aspect ratios and nanometric diameters. Both samples display predominantly hydrophilic behavior; however, only the SA sample exhibits suspended particles at the interface, suggesting a slightly higher hydrophobic character than ST sample. These findings highlight the significant impact of the geological formation environment on the structural and surface characteristics of sepiolite, which, in turn, influence its performance in applications involving dispersion, adsorption, and interfacial interactions. Full article

Background/Objectives: Within the minimum intervention oral care (MIOC) delivery framework, the management and improvement in the esthetics of enamel white spot lesions (WSLs) are recommended. This study evaluated the chemomechanical and morphological characteristics of WSLs treated by four therapeutic approaches using Raman spectroscopy, Knoop microhardness (KH), and field-emission scanning electron microscopy (FESEM). Methods: Sixty human enamel slabs were divided into six groups: non-treated (baseline), WSLs (8% methylcellulose gel with 0.1 M lactic acid, pH 4.6 at 37 °C for 21 days), and four treated groups, namely bovine collagen supplement (Nutravita Ltd., Maidenhead, Berkshire, UK), Regenerate system (NR-5, Bordeaux, France), Sylc air abrasion (AquaCare, Denfotex Research Ltd., Edinburgh, UK), and CO₂ laser (JHC1180, Jinan, China). Treatment lasted 28 days, followed by four weeks of storage in artificial saliva (pH = 7.0, 37 °C). Bovine collagen was analyzed using Fourier-Transform Infrared Spectroscopy (FTIR). The mineral content, including the phosphate peak intensities (PO₄ ν₁, ν₂, and ν₄) and carbonate (CO₃), as well as tissue microhardness, were assessed at varying depths (50–200 µm), followed by morphological assessment. Results: The FTIR spectrum of bovine collagen powder confirms the presence of amide I, II, and III. It produced a statistically significant enhancement in the phosphate content and KHN compared to WSLs of up to 150 µm in depth (p < 0.001). Regenerate-treated surfaces recorded the highest phosphate content among groups at the superficial layer. All treatment interventions enhanced the morphology of lesions by covering the exposed prisms and inter-prismatic structure. Conclusions: Bovine collagen supplements can enhance the phosphate content and surface properties of enamel white spot lesions (WSLs) and could be considered a potential modality comparable to other micro-invasive approaches for addressing incipient enamel lesions. This could significantly impact dental care management. Full article