Search Results (6,017)

The present study aims to determine the properties of sandwich mycelium-based composite panels (sandwich-MBC-panel) fabricated with a lightweight core of mycelium-based composites (MBCs) of Ganoderma lucidum and Pleurotus ostreatus and veneers of Gmelina arborea and Vochysia guatemalensis wood. Physical and mechanical properties, acoustic capacity, chemical composition (determined by FT-IR), thermal degradation, and inorganic components were evaluated. The results showed that the sandwich-MBC-panel presented a density of 0.27–0.40 g/cm³, an MC between 14.56 and 24.71%, and a water absorption between 43.64 and 61.32%. Regarding mechanical characteristics, the sandwich-MBC-panel with the highest MOR, MOE, and internal bond was that composed of G. lucidum and G. arborea. The treatment with the best tensile force value was the mixture of G. lucidum with O. pyramidale. The sandwich-MBC-panel constructed with balsawood showed the lowest noise reduction coefficient, while the panel composed of G. lucidum and P. ostreatus showed good substrate properties and appropriate carbon and nitrogen content. FT-IR spectroscopy revealed substrate degradation by fungal mycelium formation, and TGA curves showed that the MBC containing G. lucidum presented higher thermal degradation than the panel without G. lucidum, without fungal attack. The main results of this study showed that sandwich MBC panels, in which the MBC is used as a lightweight core and wood veneers are used on the faces, have the potential for use as acoustic panels and could represent a sustainable alternative to panels that are generally fabricated from synthetic materials and of low densities. Full article

This study reports the synthesis and characterization of a novel benzimidazole-derived Schiff base (BIMPB) via the condensation of (1H-benzo[d]imidazol-2-yl)methanamine with 1-phenylbutane-1,3-dione. The structure was confirmed using ¹H-NMR, ¹³C-NMR and FT-IR spectroscopy. Photophysical properties were extensively evaluated, revealing a strong S₀ → S₂ transition at 212 nm and fluorescence emission peaks at 396 and 410 nm, corresponding to π → π* and n → π* transitions. BIMPB demonstrated significant sensitivity to pH variations, exhibiting blue shifts of 11–23 nm across different environments. Furthermore, the compound acts as a fluorescent chemosensor for Cu²⁺ and Ca²⁺ ions, where coordination leads to a substantial reduction in fluorescence intensity accompanied by a distinct blue shift. The interaction between BIMPB and DNA was investigated using UV-Vis and fluorescence titration. The results showed a hypochromic effect and a minor shift in the absorption peak from 342 nm to 340 nm, suggesting a binding mechanism dominated by intercalation or electrostatic interactions. A high binding constant (K_b = 2.1 × 10⁵ M⁻¹) and a fluorescence quenching efficiency of 58.9% confirm the formation of a stable complex. Stern–Volmer analysis indicated a static quenching mechanism. These experimental findings, supported by molecular docking studies (binding energy = −8.3 kcal/mol), highlight the potential of BIMPB as a sensitive molecular probe for DNA-targeting and chemical sensing applications. Full article

In this study, we investigated the effect of ultrasound-assisted Maillard glycosylation reaction time on the structural, physicochemical, and acid-induced gel properties of Zophobas morio protein–maltodextrin (ZMP–MD) conjugates. Ultrasound treatment up to 45 min (100 kHz, 450 W, 70 °C) significantly accelerated the conjugation efficiency (15.81%) compared to that of wet heating at 70 °C for 6 h (13.62%) (p < 0.05). Fourier transform infrared spectroscopy (FT-IR) and sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) analyses confirmed that both Maillard glycosylation methods formed ZMP–MD conjugates. In addition, the results for secondary structure, surface hydrophobicity, and zeta potential revealed that the ultrasound treatment promoted greater protein structural unfolding, decreasing α-helix while increasing β-sheet and random coil content compared to wet heating. These changes in structural and physicochemical properties of ZMP–MD conjugates impacted the glucono-δ-lactone (GDL)-based acid-induced gel properties. Even though Maillard glycosylation with MD weakened gel properties compared to native ZMP, the gel obtained after 45 min of ultrasound treatment exhibited a higher storage modulus, gel strength, and water-holding capacity than the wet-heated ZMP–MD gel. In conclusion, these findings suggest that properly controlled ultrasound-assisted Maillard glycosylation can modify protein structure, potentially improving its gel properties. Full article

The synthesis of three novel, valuable bioconjugates obtained by coupling cholesterol bromoacetate with pyridine derivatives via an SN2 reaction was successfully carried out. Each of the products was fully characterized by magnetic nuclear resonance (¹H, ¹³C, APT, ¹H−¹H COSY, ¹H–¹³C HMBC, ¹H–¹³C HSQC), infrared spectroscopy (IR), and high-resolution mass spectrometry (HRMS). Full article

Four algal adsorbents were prepared from two types of green sea algae (Ulva lactuca and Ulva pertusa), either by treatment with concentrated sulfuric acid or without treatment. A comparative study of Au(III) adsorption in an HCl medium was performed. While both untreated adsorbents showed good performance at low HCl concentrations, the treated adsorbents achieved quantitative adsorption and high selectivity for Au(III) across a broad range of HCl concentrations. The adsorption of Au(III) onto the algal biomass adsorbents followed the typical Langmuir monolayer adsorption model. At an HCl concentration of 0.010 M, the maximum adsorption capacities were 1.14, 0.86, 6.57, and 6.28 mol kg^–1 for DUL, DUP, TUL, and TUP, respectively. A kinetic study conducted at different temperatures was consistent with the pseudo-first-order kinetic model and enabled estimation of the activation energy of the adsorption reaction. Structural changes before and after treatment were analyzed using FT-IR spectroscopy. Confirmation of Au(III) adsorption and its subsequent reduction to the elemental state was achieved through XRD and SEM/EDX analyses as well as digital imaging of the Au-loaded adsorbents. Finally, the adsorbed and reduced Au was successfully desorbed using an acidic thiourea solution. Full article

A heteroatom-rich pyridine-based adsorbent (Pyridine PC) was synthesized through a multicomponent strategy and structurally confirmed by ¹H/¹³C NMR spectroscopy and mass spectrometry. To further enhance adsorption activity and surface reactivity, waste-derived CuO nanoparticles were immobilized onto the porous heterocyclic framework, generating a sustainable CuO@Pyridine PC hybrid nanocomposite. Batch adsorption experiments demonstrate highly efficient removal of malachite green (MG) dye and Cd(II) ions from aqueous solutions. Kinetic analysis reveals that adsorption follows the pseudo-second-order model, while equilibrium data are best described by the Freundlich isotherm, indicating adsorption on heterogeneous surfaces. Thermodynamic parameters confirm that the adsorption processes are spontaneous and exothermic. Surface and structural characterization using SEM/EDX, elemental mapping analysis and FT-IR before and after adsorption verifies strong pollutant binding and highlights the role of nitrogen- and oxygen-containing functional groups as dominant interaction sites. BET measurements show that CuO incorporation increases surface area and pore volume, while zeta potential analysis indicates excellent colloidal stability of the composite in aqueous media. Consequently, the CuO-modified sorbent exhibits enhanced adsorption capacities, increasing from 169.8 to 176.13 mg g⁻¹ for MG and from 276.5 to 368 mg g⁻¹ for Cd(II). The adsorbent demonstrated effective pollutant removal from real wastewater. The adsorption mechanism involves synergistic interactions between functional groups in the Pyridine PC matrix and CuO nanoparticles, providing enhanced active binding sites. Full article

Background/Objectives: Curcumin (CUR) is a potent anticancer agent whose clinical application is hindered by its extremely poor aqueous solubility. This study reports the development of enzyme-responsive whey protein isolate (WPI) nanoparticles for CUR targeted delivery. Methods: To overcome the initial solubility barrier, CUR was first formulated as a solid dispersion with WPI using freeze-drying. This process resulted in a significant enhancement in aqueous solubility (up to 1478-fold), with CUR existing in molecular dispersion or in an amorphous state within the protein matrix as confirmed by Differential Scanning Calorimetry (DSC) and Fourier-transform infrared (FT-IR) spectroscopy. The solubilized CUR-WPI solid dispersion was subsequently used to generate nanoparticles via a thermal gelation method, avoiding the use of organic solvents or toxic chemical crosslinkers. Results: The resulting nanoparticles exhibited a high drug loading efficiency of 85%. In vitro release studies demonstrated minimal CUR release in physiological buffer (pH 7.4) over 24 h, whereas exposure to trypsin, a nonspecific serine protease used as an in vitro model for tumor-associated proteolytic activity, triggered rapid nanoparticle degradation and released 95% of CUR within 3 h. Conclusions: These findings suggest that WPI-based nanoparticles developed from solid dispersions offer a promising, biocompatible platform for the solubility enhancement and protease-triggered delivery of hydrophobic anticancer drugs. Full article

This work presents an energy-efficient and simple method for producing luminescent, antibacterial sulfur quantum dots (SQDs). For the first time, polyethyleneimine (PEI)-coated SQDs were synthesized via a mechanochemical technique, utilizing either elemental sulfur or sodium thiosulfate as the sulfur source. The roles of hydrogen peroxide (H₂O₂) as an etching agent and of sodium hydroxide (NaOH) in the PEI-mediated SQD formation were investigated. The as-synthesized SQDs were characterized by UV-visible, Raman, infrared (IR), and photoluminescence (PL) spectroscopy, as well as by transmission electron microscopy (TEM) and atomic force microscopy (AFM). Both TEM and AFM analyses revealed similarly small SQD sizes (average diameter ~3 nm), independent of the sulfur source used. The influence of synthesis conditions on the optical properties, including the photoluminescence quantum yield (QY), was evaluated. SQDs derived from elemental sulfur, PEI, and NaOH exhibited the best water solubility and the strongest photoemission in the 400–550 nm range. Antibacterial activity was assessed against representative Gram-positive and Gram-negative strains, and minimum inhibitory concentration (MIC) values were determined. The PEI-coated SQDs demonstrated antibacterial activity against the Gram-positive bacteria Bacillus subtilis, Staphylococcus aureus, and Staphylococcus epidermidis, which is attributed primarily to the sulfur component. Full article

This study investigated the effect of post-silanization processing on the surface chemistry and dispersion stability of 3 mol% yttria-stabilized tetragonal zirconia polycrystal (3Y-TZP) nanoparticles intended for the reinforcement of dental photopolymer resins. The nanoparticles were silanized using 3-Methacryloxypropyltrimethoxysilane and subjected to different post-treatment protocols, including control, drying, and centrifugation. Particle morphology was examined using field-emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM). Dispersion behavior was analyzed by dynamic light scattering (DLS) and zeta potential measurements, performed in triplicate (n = 3), while surface chemical modifications were evaluated using Fourier transform infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS). Post-silanization processing significantly influenced nanoparticle surface chemistry and dispersion stability. Centrifugation promoted the formation of Si-O-Zr and Si-O-Si linkages, reduced loosely adsorbed silane species, decreased particle agglomeration, and increased zeta potential magnitude, resulting in a more uniform hydrodynamic size distribution compared to the dried group (Z-average » 814 nm, PDI » 0.44). These findings suggest that post-silanization centrifugation acts as an interfacial selection mechanism that distinguishes covalently grafted silane from weakly adsorbed species. Within the limitations of this in vitro study, further investigations under varied conditions are required to confirm broader applicability. Full article

Due to biodegradability, functionalization, and sustained release, polymer-based films are widely used in different industries. This study explores a bioactive emulsion-based film obtained using high-methoxy pectin (HMP), Origanum onites L. essential oil, and a hydroalcoholic extract of Thymus vulgaris L., prepared using various emulsion recipes. The emulsions obtained were applied to cellulose supports intended for topical applications. Bioactive textiles were analyzed using SEM-EDS elemental mapping, ATR FT-IR spectroscopy, biocompatibility assessment, antimicrobial activity assays, and analysis of comfort indices. SEM images of textile supports treated with bioactive emulsions confirmed the creation of a film surface and that the homogeneity of the film increases with increasing amount of glycerin, which acts as a plasticizer. Infrared spectra combined with their second derivatives and PCA indicate the presence of oregano essential oil, thyme extract, and pectin on the surface of the cotton. The biocompatibility evaluation of functionalized cotton supports revealed minimal cytotoxic effects on HaCaT human keratinocytes after 24 h of exposure. The results of the analyses showed that bioactive textile supports also exhibit antimicrobial activity. Therefore, the active emulsions with pectin, oregano essential oil, and hydroalcoholic extract of thyme provide biocompatible and antimicrobial active films by applying on cellulosic supports. Full article

5-Fluorouracil (5-FU) is a cornerstone chemotherapeutic agent that is extensively utilized in the management of malignancies; however, its clinical utility is constrained by its narrow therapeutic index and dose-limiting toxicities. The study aimed to study the hepato-nephroprotective effects of epigallocatechin gallate (EGCG) and EGCG mediated selenium nanoparticles and their effect in mitigating the toxicity induced by 5-FU. EGCG-functionalized selenium nanoparticles (EGCG-SeNPs) were produced by mixing sodium selenite, with EGCG acting as both the reducing and stabilizing agent. Nanoparticles were characterized using UV-vis spectroscopy, FT-IR, dynamic light scattering, zeta potential analysis, and transmission electron microscopy. 35 adult rats were randomly assigned to control, 5-FU, 5-FU + Na₂SeO₃, 5-FU + EGCG, and 5-FU + EGCG-SeNPs groups. Hepatorenal toxicity was induced by intraperitoneal 5-FU administration during the final five days of the experiment. Serum biochemical markers, tissue oxidative stress, antioxidant enzyme, inflammatory cytokine levels, and apoptosis-related gene expression were evaluated. Immunohistochemical analysis of Nrf2 and Keap1 and histopathological examination of tissues were performed. 5-FU induced severe hepatorenal toxicity, evidenced by marked elevations in liver and kidney function biomarkers, excessive oxidative stress, inflammatory cytokine overproduction, NF-κB activation, and apoptotic signaling. Treatment with EGCG-SeNPs markedly ameliorated 5-FU-induced hepatic and renal dysfunction, restoring liver enzyme and kidney biomarker levels to near-normal levels more effectively than EGCG or sodium selenite alone. EGCG-SeNPs significantly suppressed lipid peroxidation, NGAL, and inflammatory mediators while robustly enhancing antioxidant defenses and activating the Nrf2/HO-1 pathway with concomitant Keap-1 downregulation, strongly inhibited NF-κB signaling, normalized cytokine balance, reduced poly (ADP-ribose) (PAR) activation, and attenuated apoptosis. EGCG–SeNPs confer superior protection against 5-FU–induced hepatorenal toxicity compared to EGCG or inorganic selenium alone. The potent protective effects of EGCG–SeNPs are mediated through coordinated antioxidant, anti-inflammatory, and anti-apoptotic mechanisms, primarily via activation of the Nrf2/HO-1 axis and suppression of NF-κB signaling. Full article

This article describes a study on the synthesis and annealing processes of thin-film coatings of vanadium oxide on flat, parallel substrates made of quartz glass, sapphire, and silicon, as well as optical fibers using an organometallic precursor, triisopropoxy vanadium (V) oxide. For the first time, optical constants of nanomaterials were estimated in real time during synthesis and subsequent annealed using the lossy-mode resonance effect. The coatings produced in an inert atmosphere after deposition were amorphous, comprising a mixture of VO₂, V₂O₅, V₆O₁₃, and V₃O₅. This method allowed for accurate determination of the threshold temperature for the transformation of oxide mixtures into a monocomponent phase. Optimal conditions for synthesis and annealing were determined for the production of vanadium dioxide (VO₂) and pentoxide (V₂O₅). Morphological changes in coated surfaces were observed as a result of heat treatment. The composition and properties of these samples were studied using optical, terahertz and Raman spectroscopy, as well as temperature-dependent analysis of electrical resistance. The morphology of the coating surface was determined using a scanning electron microscope and an atomic force microscope. The reduction of VO_x to VO₂ was studied in an atmosphere of hydrogen and argon during annealing after deposition, with its effectiveness being compared. It was shown for the first time that the reduction of higher vanadium oxides is due to the presence of elemental carbon in the volume of the material formed from a metalorganic precursor during growth of vanadium oxide. Coatings obtained by annealing in hydrogen had a smaller hysteresis loop width (~5 °C) during phase transition compared to coatings obtained by argon annealing (~9 °C). Both types of coatings demonstrated a 50–60% increase in transmission at 1 THz frequency and in the IR region, accompanied by a 10³–10⁴-fold change in electrical resistance. Full article

The removal of excessive amounts of antibiotics from water systems is of great benefit due to their adverse effects on the ecosystems, living organisms and the persistent increase in antibiotic resistance cases. This study was focused on the adsorption of vancomycin from a simulated aqueous medium using seaweed, a sustainable and low-cost adsorbent. Also, the work focuses on assessing the influence of surface modification on adsorption behaviour and determining if chemical treatment provides improvements over untreated seaweed. In particular, chemically modified seaweed and raw (non-modified) seaweed were assessed as adsorbents suitable for removing traces of vancomycin from water, as gauged from the results of High-Performance Liquid Chromatography (HPLC). In addition, Scanning Electron Microscopy (SEM), Fourier Transform Infrared spectroscopy (FT-IR) and the pH point of zero charge (pHpzc) were used to measure the surface characteristics of these adsorbents. The degree of antibiotic adsorption was evaluated as a function of different factors, including the pH, adsorbent dosage, contact time, ionic strength and initial concentration of vancomycin. Thermodynamic parameters, such as the enthalpy change (∆H°), the entropy change (∆S°) and the free-energy change (∆G°), were calculated. The FTIR analysis indicates that functional groups, such as carbonyl and hydroxyl groups, were involved in the adsorption process, and their modification influenced adsorption behaviour. It was observed that the adsorption of vancomycin by the modified seaweed was slightly lower (±94%) compared to the level achieved for the raw seaweed (±97%). These figures were obtained with an initial concentration of vancomycin of 25 µg/mL, a pH of the aqueous solution of 7.0, an adsorbent dose of 0.2 g and a contact time of 120 min. The results showed that untreated seaweed exhibited slightly higher adsorption efficiency than the treated seaweed, suggesting that chemical modification might not have enhanced adsorption performance. The thermodynamic parameters suggested that the adsorption process was exothermic and that adsorption was favourable for the untreated seaweed and less favourable for the treated seaweed. Regeneration studies showed a decrease in adsorption efficiency over repeated cycles. Although the adsorption capacity is lower than that of advanced nanomaterials, the use of seaweed offers an advantage in terms of low cost, availability and environmental sustainability. The comparable efficiency of the modified and untreated seaweed adsorbent suggests that seaweed adsorbents can be used as viable bio-adsorbents for the decontamination of water. Full article

Photocatalytic hydrogen production represents a promising approach for sustainable fuel generation, particularly when driven by solar irradiation. In this study, a photocatalytic system composed of eosin Y, cobalt sulfate, triethanolamine, and graphene oxide was investigated for hydrogen evolution. The optical and structural properties of the system components were characterized using UV–Vis spectroscopy, FT-IR spectroscopy, Raman spectroscopy, and atomic force microscopy. Photocatalytic activity was evaluated under both artificial light sources (halogen lamp, xenon lamp, and LED 505 nm) and natural sunlight in order to assess system performance under realistic environmental conditions. The addition of graphene oxide significantly enhanced hydrogen production, resulting in an approximately 4-fold increase compared to the three-component system without graphene oxide. Solar-driven experiments conducted over one year demonstrated efficient hydrogen evolution under a wide range of weather and irradiance conditions. Importantly, based on combined experimental and meteorological data, it is shown that high photocatalytic performance is achievable for a substantial fraction of the year, with approximately 55% of days expected to provide at least 80% of the maximum hydrogen production efficiency under Central European climatic conditions. These findings highlight the strong potential of the investigated four-component system for efficient hydrogen generation using low amounts of catalytic material and without external electrical energy input. Overall, the system shows promising performance for solar-driven hydrogen production under real-world solar irradiation conditions. Full article

Ultrafast fiber lasers operating near 2 μm have emerged as a critical platform for advancing mid-infrared photonics due to their narrow pulse durations, high peak powers, and broad tunability. These sources exploit the rich energy-level structures of Tm³⁺ and Ho³⁺ doped fibers and reside within an atmospheric transmission window, enabling applications spanning nonlinear microscopy, precision micromachining, optical frequency metrology, biophotonics, and free-space optical communication. Recent progress in low-loss fiber fabrication, dispersion-engineered cavity design, and mode-locking technologies has significantly expanded the performance boundaries of 2 μm ultrafast fiber lasers. This review systematically examines the underlying pulse-formation mechanisms and categorizes state-of-the-art mode-locking approaches. Representative laser architectures are compared with respect to pulse duration, energy scalability, repetition-rate enhancement, spectral characteristics, and environmental stability. Key application pathways in high-resolution spectroscopy, biomedical diagnostics, and mid-IR supercontinuum generation are highlighted. Finally, the remaining challenges and prospective research directions are discussed to inform the development of next-generation ultrafast photonic sources in the 2 μm band. Full article