Search Results (6,098)

PVP-stabilized silver nanoparticles (Ag NPs) were functionalized with sildenafil (Sil), leading to spherical NPs (Ag@Sil NPs) with a size of about 30 nm as observed through transmission electron microscopy and dynamic light scattering. Fourier-transformed IR spectroscopy confirmed the covering of the particles with Sil. The Ag@Sil NPs were incorporated into a 0.1 wt% ointment and tested for the treatment of acute anal fissures in a preliminary medical study involving 50 patients. Typical symptoms such as pain, bleeding, itching, and mass sensation were improved in the intervention group with no adverse effects. Molecular docking showed strong interactions with docking scores slightly above −10 kcal/mol between sildenafil and two different model complexes [Ag–Sil]⁺ for the Ag-bound sildenafil with either piperazine-N- or pyrazole-N-bound Ag⁺ ions and the muscarinic M2 and the nicotinic acetylcholine α3β4 receptor, which are both involved in anal sphincter regulation. All three showed superior binding compared with nitroglycerin and L-arginine. The residue analysis revealed a higher number of relevant interactions for the sildenafil and the two Ag⁺ complexes, compared to nitroglycerin and L-arginine, fully in line with the differences in the docking scores. Full article

Light-triggered hydrogel systems offer precise spatiotemporal control over drug release, yet most existing approaches require direct chemical conjugation of a photocleavable linker to the payload, which risks compromising bioactivity and limits applicability to structurally diverse molecules. Here, we report a gelatin–poly(ethylene glycol) (PEG) hybrid hydrogel crosslinked via strain-promoted azide–alkyne cycloaddition (SPAAC) click chemistry, in which an o-nitrobenzyl photocleavable (PC) linker is incorporated into the PEG crosslinker arm rather than conjugated to the drug. Acetylated gelatin–azide (AGA) was synthesized by sequential azide functionalization and amine capping of gelatin, and four-arm PEG-PC-DBCO (4armPEG-PC-DBCO) was prepared by coupling a PC DBCO-PEG4-NHS ester to four-arm PEG amine. Successful incorporation of the azide, DBCO, and o-nitrobenzyl moieties was confirmed by FT-IR spectroscopy, ¹H NMR spectroscopy, and UV-Vis spectrophotometry. Hydrogel formation under physiological conditions (PBS, 37 °C) without catalysts or initiators was verified by rheological frequency sweep analysis, which confirmed elastic-dominant behavior (G′ > G″). Upon irradiation at 365 nm, the crosslinker was cleaved, and rapid network dissolution was observed both macroscopically and by in situ time sweep rheology. This platform enables on-demand, UV-selective hydrogel degradation independently of payload identity, providing a versatile foundation for future controlled drug release applications and dynamic, on-demand degradable scaffolds for tissue engineering. Full article

Background/Objectives: Oral candidiasis is an infection of the oral cavity caused by Candida albicans. Mucoadhesive buccal films could adhere to the buccal mucosa for prolonged periods, improving the therapeutic outcomes of patients with oral candidiasis. This study aimed to develop and evaluate the properties of fluconazole containing sodium alginate/methylcellulose-based buccal films for potential treatment of oral candidiasis. Methods: Drug-polymer compatibility was investigated using FT-IR spectrophotometry. Three optimised fluconazole films (F1 to F3) containing 1–1.6% sodium alginate and methylcellulose (1.6%) were formulated using the solvent-casting method. Their physicomechanical properties were characterised using standard protocols. Drug content and in vitro drug release profiles were evaluated using UV-visible spectroscopy; in vitro/ex vivo mucoadhesion studies were conducted using the shaking water bath technique, and their antifungal activity against Candida albicans was evaluated using the agar ditch method. Results: FT-IR data analysis revealed that sodium alginate, methylcellulose and fluconazole were compatible in the films. The films were off-white, smooth, peelable, thin, with satisfactory pH values, folding endurance, drug content, excellent zones of inhibition against Candida albicans (40 mm), controlled drug release profile (3.6–4.1 mg/cm² after 6 h), and they displayed Korsmeyer–Peppas drug release kinetics. Film F3 containing 1.6% sodium alginate and 1.6% of methylcellulose exhibited superior swelling index (70 ± 1%), tensile strength (0.68 ± 0.04 MPa) and in vitro/ex vivo mucoadhesion time (5.5 ± 0.3 h; 2.3 ± 0.3 h) relative to other studied films. Conclusions: The sodium alginate content of the films influenced their tensile and mucoadhesive properties. Film F3 was the most promising formulation for potential treatment of oral candidiasis. Full article

A nitrogen/sulfur co-doped reduced graphene oxide (N,S-RGO) material was rationally prepared via a modified Hummers method followed by microwave-assisted reduction. The resulting material was uniformly deposited onto a glassy carbon electrode (GCE) to fabricate an electrochemical sensor for nitrobenzene (NB) detection. The prepared N,S-RGO material was characterized in detail using Fourier-transform infrared spectroscopy (FT-IR), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and Raman spectroscopy, confirming the successful incorporation of heteroatoms. Furthermore, electrochemical studies, including cyclic voltammetry (CV) and linear sweep voltammetry (LSV), revealed the enhanced electrical conductivity of the material. The fabricated N,S-RGO/GCE sensor exhibited remarkable electroanalytical performance, achieving a low detection limit (LOD) of 7 nM within a linear concentration range of 0.05 to 147 µM. The enhanced sensing performance is attributed to the synergistic effect of nitrogen and sulfur doping, which improves electron transfer kinetics and abundant active sites for NB reduction. Furthermore, the sensor demonstrated outstanding selectivity toward NB in the presence of common interfering substances. Its practical applicability was confirmed through the successful detection of NB in environmental water samples, yielding convincing recovery rates. These results highlight the potential of the N,S-RGO/GCE platform as an efficient and reliable electrochemical sensor for environmental monitoring of NB contamination. Full article

Gliomas are highly aggressive tumors of the nervous system and remain difficult to treat with currently available therapeutic approaches. Due to their poor prognosis and resistance to standard treatments, there is a growing need for novel strategies, including therapies based on the combined use of radiotherapy and chemotherapy. The aim of this study was to evaluate the potential of newly synthesized hydrazide–hydrazones to sensitize glioblastoma tumor cells to X-ray irradiation. Two novel hydrazide–hydrazones of 5-bromo-2-iodobenzoic acid (3 and 4) were synthesized on the basis of condensation reaction. The chemical structure of obtained compounds was established with the use of IR, ¹H NMR and ¹³C NMR spectroscopy. In vitro biological studies demonstrated that the radiosensitizing effect of the tested hydrazide–hydrazones was strongly dependent on both compound concentration and glioblastoma cell line. In LN-229 cells, compound 3 at 164 μM combined with 2 Gy irradiation reduced cell viability by 65% and increased the subG1 population, indicating enhanced cytotoxicity and induction of cell death. Similarly, compound 4 at 242 μM combined with 2–5 Gy irradiation decreased LN-229 cell viability by more than 50% and promoted cell cycle arrest and apoptosis, whereas both compounds showed limited or even proliferative effects in U-87MG cells, highlighting the importance of tumor-specific biological characteristics in determining treatment response. Full article

Potato starch (Solanum spp.) undergoes structural and functional modifications during traditional Andean chuño production; however, the integrated effects of processing history, cultivar-associated characteristics, and field-based environmental conditions remain insufficiently characterised. This study investigated the effects of chuño processing on the compositional, pasting, morphological, molecular, and crystalline properties of starches isolated from three potato cultivars (Condor Imilla, Luk’i Turno, and Dutch Désirée). Native and chuño starches were characterised by amylose quantification, viscoamylography, scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FT-IR), and X-ray diffraction (XRD), together with severe thermal treatment to evaluate structural stability. Chuño processing was associated with a reduction in amylose content across all cultivars (6.9–23.4%) and an increase in gelatinisation onset temperature of approximately 21.5% (from ~65 °C to ~79 °C). Peak viscosity decreased substantially after processing (457.5–1110 BU to 194.5–442.5 BU), while breakdown values remained close to zero, indicating increased resistance to viscosity loss during heating. SEM analysis revealed changes in granule morphology and size distribution associated with chuño processing and subsequent thermal treatment, with more pronounced reductions in granule size observed in Condor Imilla and Luk’i Turno than in Dutch Désirée. FT-IR analysis demonstrated modifications in short-range molecular organisation without the appearance of new functional groups, indicating structural reorganisation rather than chemical transformation. XRD analysis confirmed that all starches retained the native B-type crystalline polymorph after chuño processing, although reductions in diffraction intensity and peak definition indicated decreased long-range structural order. Severe thermal treatment eliminated detectable crystalline order in all samples, producing predominantly amorphous diffraction profiles. Overall, chuño processing was associated with reduced swelling capacity, lower paste viscosity, enhanced thermal stability, and multiscale structural reorganisation while preserving the fundamental B-type polymorph. Given that the plant material originated from distinct agroecological environments and that traditional chuño production involved a variable number of processing cycles, the observed differences should be interpreted as integrated responses of starch systems to processing history and material characteristics rather than strictly genotype-driven effects. These findings highlight the potential of chuño as a naturally modified starch system with distinctive technological properties. Full article

To enhance the temperature, salt and shear resistance of conventional polyacrylamide oil-displacing agents, a fluorinated hydrophobically associating polymer AM-AA-HDFDMA was synthesized by aqueous solution polymerization. Acrylic acid (AA) and acrylamide (AM) were utilized as comonomers, with perfluorooctylethyl methacrylate (HDFDMA) serving as the fluorinated hydrophobic functional monomer. The synthesis employed an ammonium persulfate-sodium bisulfite (APS-NaHSO₃) redox initiation system. The selected synthesis conditions were established as a total monomer mass fraction of 25%, an initiator dosage of 0.3 wt% of the total monomers, a reaction temperature of 40 °C, and a reaction time of 4.5 h. The chemical structure and micromorphology of the polymer were characterized by Fourier transform infrared spectroscopy (FT-IR), proton nuclear magnetic resonance (¹H-NMR), and scanning electron microscopy (SEM). Furthermore, its thickening performance, shear resistance, temperature resistance, salt tolerance, and oil displacement efficiency were systematically evaluated. Full article

The objective of this study was to examine the physicochemical properties of maltodextrins derived from starch isolated from red- and purple-fleshed potatoes, in comparison to those obtained from light-fleshed potatoes. The investigation focused on several parameters, including dextrose equivalent (DE), non-carbohydrate components, maltooligosaccharide profile, particle size, surface morphology, water-binding capacity, solubility, rheological properties, structural composition as determined by Fourier transform infrared spectroscopy (FT-IR), and molecular weights. Maltodextrins sourced from the starch of colored potato varieties exhibit superior functional properties, notably nearly 100% solubility and enhanced water absorption capacity. This is attributed to their fine microstructure, which promotes hydration and facilitates the diffusion of water into the interior of the particles, in contrast to maltodextrins derived from the starch of yellow potato varieties. This phenomenon is also influenced by the maltooligosaccharide profile, characterized by a high proportion of low-molecular-weight sugars, lower molecular weights, and polydispersity (Pd), as well as the low SPAN of these maltodextrins. Additionally, maltodextrins derived from the starch of yellow potato varieties (Tajfun and Lord) formed soft gels, whereas those from colored potatoes resulted in hard gels. Full article

This study aimed to systematically compare the functional properties of the four major components (albumin, globulin, prolamin, and glutelin) of protein from Yunnan deep-veined walnuts to screen for protein-based carrier materials with good processing adaptability and the ability to efficiently encapsulate the active ingredient rutin. In addition, the binding and molecular interactions between the preferred protein and rutin were analyzed. The results indicated that albumin exhibited superior performance compared to the other three components in solubility, emulsifying properties, foaming properties, and gel properties, and demonstrated the strongest processing applicability. Further analysis revealed that albumin possessed an excellent amino acid composition (essential amino acid content accounting for 42.30%) and antioxidant activity (with the highest ABTS scavenging rate reaching 85.71 ± 0.26%), which indicated its considerable potential as a functional carrier. Loading rutin onto albumin yielded a walnut albumin–rutin complex (WA@Rut), which significantly enhanced the thermal stability of albumin (with the thermal denaturation temperature elevated to 108.72 °C) and the storage stability of rutin (66.16 ± 5.05% retention after 22 days of storage). Combined analyses of FT-IR spectroscopy, intrinsic fluorescence spectroscopy, molecular docking, and molecular dynamics simulations confirmed that rutin primarily bound to albumin via hydrogen bonding and electrostatic interactions, and formed a stable complex structure. SEM images revealed that the composite surface was smooth and exhibited a flake-like morphology. In conclusion, walnut albumin is a protein resource with significant functional potential in Yunnan deep-veined walnuts, and it exhibits strong processing applicability and enables efficient encapsulation and protection of active ingredients. This study provides novel strategies and theoretical foundations for the high-value utilization of walnut protein. Full article

New lacunary Keggin-type polyoxometalate salts with the formula Cs₅PMMo₁₁(H₂O)O₃₉ (M = Cu, Zn) were synthesized via the inorganic solution condensation method. X-ray diffraction and FT-IR spectroscopy confirmed the preservation of the Keggin structure. The surface morphology and elemental composition were characterized using scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy. Thermal analysis, performed by differential scanning calorimetry coupled with thermogravimetry, demonstrated a significant enhancement in thermal stability upon the incorporation of the transition metals into the heteropolyacid framework. Specifically, the substitution of protons by cesium and of molybdenum by copper or zinc positively influenced the crystallographic configuration of the salts, raising their thermal resistance (up to 526 °C). Furthermore, optical and dielectric measurements revealed promising electronic properties in the synthesized lacunary salts. Notably, the compound Cs₅PZnMo₁₁(H₂O)O₃₉ exhibited a substantially increased dielectric constant at low frequency, underscoring the synergistic effect of zinc addition on its dielectric performance. Full article

This study investigated the valorization of keratin extracted from sheep wool waste for the preparation of PLA/SBS/Keratin composites as potential adsorbents for the removal of chromium (Cr) from synthetic water. A flexible formulation containing 75 wt% PLA and 25 wt% SBS was selected for the incorporation of 10 wt%, 20 wt%, and 30 wt% keratin. The morphology and structural characteristics of keratin and PLA-based composites were analyzed using SEM and FT-IR spectroscopy. The mechanical and thermal properties of the prepared composites were investigated using TGA and DMA analyses. The adsorption experiments revealed that keratin exhibited an adsorption capacity of 57.57 mg g⁻¹ of Cr(VI) removal efficiency, while the PLA/SBS formulation containing 10 wt% keratin achieved a removal efficiency of total Cr of 55.41%. After three regeneration cycles, the removal efficiency decreased by approximately half of the total Cr removal. Full article

Hypogeous ascomycetous fungi (truffles) are challenging to study because they produce underground sporocarps that may not be encountered during traditional fungal surveys. Genea is one such genus that has garnered considerable attention over the past decades due to its role as an ectomycorrhizal partner and contribution to nutrient cycling and ecosystem stability. Yet, very limited information is available about its taxonomy, phylogeny and ecology worldwide. The current study aims to expand the known distribution of Genea species in Central Europe by integrating morphological, molecular and ecological analyses of new collections as well as the assessment of herbarium materials. Light microscopy and SEM were used to determine morphological characteristics along with FT-IR (Fourier transform infrared) spectroscopy measurements, which proved to be a powerful tool for species differentiation. Molecular phylogenetic analyses were conducted using the internal transcribed spacer (ITS1-5.8S-ITS2 = ITS) and D1/D2 domain of the large subunit (28S) of nuclear ribosomal DNA sequences to confirm species identity. In this study, a new species, Genea szemereiensis, along with the first report of Genea pinicola from Hungary, was made. In addition, the ecological parameters of the species, including habitat, altitude, soil nutrients and pH, were revised, which has not been reported previously in detail for this genus. Full article

Direct ammonia fuel cells (DAFCs) offer a promising pathway for carbon-free energy conversion but their practical performance is limited by sluggish cathode kinetics. In this work, non-precious FeCoN catalysts offer a cost-effective solution, yet carbon support optimization is crucial for activity and stability. FeCoN/XC-72R, FeCoN/CNT, and FeCoN/CNH cathode catalysts were synthesized by annealing at 550–750 °C. Their structure and morphology were analyzed by X-ray diffraction (XRD) and scanning electron microscopy (SEM). Electrochemical behavior was evaluated by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) in alkaline medium containing KOH and NH₄OH. FeCoN/XC-72R exhibited the lowest resistance of 27 Ω and superior activity. In single cell tests using a 40 wt% PtIr/C anode catalyst at 2 mg cm⁻², the FeCoN/XC-72R catalyst achieved the highest power density of 71 mW/cm² under optimized conditions of 0.1M NH₄OH + 3M KOH, 100 °C, and O₂ feed. Among the carbon supports, carbon black (XC-72R) proved the most effective support for FeCoN catalysts in low concentration DAFCs, outperforming carbon nanotubes (CNTs) and carbon nanohorns (CNHs). These findings highlight the importance of carbon support selection in the design of efficient cathodes for next generation low concentration direct ammonia fuel cells. Full article

This study investigates the effects and mechanisms of three mineral admixtures—fly ash (FA), silica fume (SF), and metakaolin (MK)—on the fresh, mechanical, and microstructural properties of Yellow River sediment (YRS)-based shotcrete. A comprehensive experimental program was conducted, including setting time determination, workability assessment, and mechanical strength evaluation, complemented by microstructural characterization using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), and scanning electron microscopy (SEM). The results indicate that the incorporation of FA prolonged initial and final setting times and improved pumpability but reduced build-up thickness and compressive strength; splitting tensile strength at later ages remained comparable to the control. SF shortened the final setting time and reduced flowability but enhanced shootability, layer build-up, and medium- to later-age compressive and tensile strengths, with an optimal dosage of 5%. MK accelerated the final setting time, slightly reduced early-age compressive strength, but improved early-age splitting tensile strength and achieved 28-day compressive strength comparable to the control. Microstructural analyses revealed that FA participates in pozzolanic reactions forming C–(A)–S–H gel, while SF and MK promote the formation of dense C–S–H and carboalumination phases, enhancing matrix densification. Based on performance evaluation, the recommended dosages are FA ≤ 20%, SF ≤ 15%, and MK ≤ 15%. These results establish clear links between macroscopic performance and microstructural evolution, providing experimental guidance for the sustainable development of YRS-based shotcrete. Full article

An efficient catalyst for the reaction of ethanol–acetaldehyde into 1,3-butadiene (EATB) is prepared through the grafting of zirconia into a zeolite Beta lattice. The grafting is achieved through the dealumination of a zeolite framework by acid treatment followed by zirconia impregnation, leading to the substitution of aluminum in the zeolite framework by zirconia. The catalyst with zirconia grafted into the zeolite framework promotes desirable catalyst properties like high zirconium dispersion, stability, and the close proximity of Lewis acid, Bronsted acid, and medium basic sites. The phase, the coordination of zirconia, the location of the active center and the cooperative synergism were elucidated through various characterization techniques, including X-ray diffraction, Raman spectroscopy, N₂ adsorption, UV–vis spectroscopy, XPS, ²⁹Si MAS NMR, NH₃-TPD, Py-IR, CO-IR and CO₂-TPD. The catalytic results show that a suitable phase and content of zirconia were needed to improve the ethanol–acetaldehyde conversion, butadiene selectivity and catalyst stability. Among the catalysts, m+t-ZrO_x-Beta-H₂O-9020 (m = monoclinic, t = tetragonal ZrO₂ phase) achieved the best butadiene selectivity of 82–73% at the conversion of 100–66%, run over 200 h. The results allow us to propose a Lewis acid–medium basic pairing for the Si–O–Zr–O–Si group, where the adjacent Si-OH is the active center for reactions. Full article