Search Results (958)

This study presents the synthesis and comprehensive characterization of tin dioxide nanoparticles (SnO₂NPs). SnO₂NPs were obtained using a conventional wet-chemistry route and an environmentally friendly green-chemistry approach employing plant extracts from rooibos leaves (Aspalathus linearis), pomegranate seeds (Punica granatum), and kiwifruit peels (family Actinidiaceae). The thermal stability and decomposition profiles were analyzed by thermogravimetric analysis (TGA), while their structural and physicochemical properties were investigated using X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDS), ultraviolet–visible (UV–Vis) spectroscopy, dynamic light scattering (DLS), Raman spectroscopy, and attenuated total reflectance Fourier-transform infrared (ATR-FTIR) spectroscopy. Transmission electron microscopy (TEM) confirmed the nanoscale morphology and uniformity of the obtained particles. The photocatalytic activity of SnO₂NPs was evaluated via the degradation of methyl orange (MeO) under UV irradiation, revealing that nanoparticles synthesized using rooibos extract exhibited the highest efficiency (68% degradation within 180 min). Furthermore, surface-enhanced Raman scattering (SERS) spectroscopy was employed to study the adsorption behavior of L-phenylalanine (L-Phe) on the SnO₂NP surface. To the best of our knowledge, this is the first report demonstrating the use of pure SnO₂ nanoparticles as SERS substrates for biologically active, low-symmetry molecules. The calculated enhancement factor (EF) reached up to two orders of magnitude (10²), comparable to other transition metal-based nanostructures. These findings highlight the potential of SnO₂NPs as multifunctional materials for biomedical and sensing applications, bridging nanotechnology and regenerative medicine. Full article

Hybrid membranes are promising alternatives for various applications, combining a continuous polymer phase with a dispersed filler phase to achieve synergistic functional benefits. The ideal fillers should possess well-defined structures and unique properties for multi-functionality, as well as being sourced from renewable, biodegradable materials for sustainability purposes. This study explored the potential of using cellulose-based renewable materials as fillers for hybrid polymer electrolyte membranes (PEMs) in fuel cells. Cellulose whiskers (CWs), known for their high crystallinity and elastic modulus, were effectively synthesized via optimized sequential alkali treatment and acid hydrolysis. Subsequent functionalization with citric acid was performed to enhance their reinforcing properties and overall performance. Initial characterization using ATR-FTIR and XRD confirmed the CWs’ structural composition, high crystallinity, and the presence of reactive groups (sulfate and hydroxyl). The functionalization process introduced new carbonyl groups (C=O), which was verified by ATR-FTIR, while maintaining high hydrophilicity. Morphological analysis revealed that the crosslinked CWs created a denser and more compact microstructure within the membrane, leading to a significant enhancement in mechanical strength. The modifications to the cellulose whiskers not only improved structural integrity but also boosted the membrane’s ion exchange capacity (IEC) and proton conductivity compared to membranes with unmodified CWs. Initial experiments demonstrated CWs’ compatibility as a filler in a polysulfone (PSU) matrix, forming hybrid membranes suitable for fuel cell applications. Full article

Citrus fruit cultivation and processing are constantly rising due to the increasing market demand and diverse utilization potentials. This generates large quantities of residues, predominantly composed of citrus peels. This study aimed to evaluate six different citrus peels using rapid and/or nondestructive instrumental analytical techniques such as ATR-FTIR spectroscopy, spectrophotometric assays, image textural analysis and physicochemical parameter determination. Image textural features managed to discriminate citrus peels based on their structure uniformity, which was found increased in lemon (C. limon) and yellow grapefruit (C. paradisi), whereas clementine (C. clementina) and red grapefruit (C. paradisi) images exhibited an increased non-uniformity of the structure. Physicochemical parameters provided insights into the quality characteristics of citrus peels, while their high ascorbic acid content seems to enhance their antioxidant activity. The obtained results from phenolic and flavonoid content determination indicated a high concentration of polyphenols in the peels, which is aligned with the ATR-FTIR spectra absorption bands. Furthermore, the spectrophotometric assays’ strong correlation suggests that the antioxidant activity of citrus peels is mainly attributed to polyphenols. Ultimately, a chemometric model was employed to provide a comprehensive understanding of the analytical methods’ interactions. Hence, citrus peels’ significant biochemical and, consequently, economic value can be highlighted, underscoring the importance of further research. Full article

Saliva is a biological fluid that can be found at various crime scenes and mainly presents two challenges for the forensic analysis: its identification and the estimation of the time since deposition (TSD). In this study, the performance of Partial Least Squares Regression (PLSR) and Principal Component Regression (PCR) models is compared for estimating the TSD of human saliva stains using Attenuated Total Reflectance Fourier-Transform Infrared Spectroscopy (ATR-FTIR). Saliva samples were obtained from eight donors and deposited on various surfaces, exposed to different environmental conditions (indoor and outdoor) and analyzed over a period ranging from 0 to 212 days. The results indicate that PLSR outperforms PCR in terms of Root Mean Squared Error (RMSE) in all cases. This improvement is particularly evident on paper surfaces, where PLSR reduces the RMSE by 10.45 days under indoor conditions and by 13.47 days under outdoor conditions compared to PCR. On woven surfaces, PLSR improves the RMSE by 3.19 days under indoor conditions and by 8.27 days under outdoor conditions compared to PCR. These results highlight the potential of vibrational spectroscopy combined with chemometric methods for the in situ forensic analysis of biological fluids at crime scenes. Full article

Traditional nanoparticle synthesis methods often rely on hazardous chemicals, raising concerns about their environmental impact. This study reports the green synthesis of zinc oxide (ZnO) nanoparticles using aqueous extracts from three distinct parts of Agave tequilana: the stalk (ZnO-S), heart (ZnO-H), and leaves (ZnO-L). The aim was to explore the influence of the different plant parts, each with their respective phytochemical profile, on the structural, optical, and antibacterial properties of the resulting nanoparticles. The synthesized ZnO-NPs were extensively characterized using UV–Vis spectroscopy, ATR-FTIR, X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), and energy-dispersive X-ray spectroscopy (EDS). The results revealed that ZnO-S exhibited the smallest particle size (~18.3 nm), the highest crystallinity, and the most uniform morphology. Optical analysis showed bandgap energies of 3.13 eV (ZnO-S), 2.99 eV (ZnO-H), and 3.02 eV (ZnO-L), with ZnO-S demonstrating enhanced UV absorption and reactive oxygen species (ROS) generation potential. Antibacterial assays against Staphylococcus aureus and Escherichia coli confirmed strong bactericidal activity for all samples, with ZnO-S showing the largest inhibition zones, approaching the efficacy of the reference antibiotic kanamycin. This work highlights the fundamental roles of plant-derived phytochemicals as natural reducing and capping agents and emphasizes the valorization of agave stalk and leaves, traditionally treated as agricultural waste for cost-effective and eco-friendly nanomaterial production. The findings reveal the untapped potential of Agave tequilana as a sustainable source for high-performance nanomaterials, paving the way for green innovations in antimicrobial and environmental applications. Full article

This study investigates chitosan extracted from in vitro cultures of Hericium erinaceus and Pleurotus ostreatus mushrooms as a novel antimicrobial matrix. The physicochemical properties including specific surface area, pore volume, and molecular structure were characterized by BET, SEM, and FTIR-ATR analyses. Chitosan from P. ostreatus exhibited a higher specific surface area (0.39 m²/g) compared to H. erinaceus (0.73 m²/g) and commercial chitosan (1.16 m²/g), correlating with enhanced antimicrobial activity against Gram-negative and Gram-positive bacterial strains. Antibacterial efficacy was quantitatively evaluated by inhibition zone diameters, with P. ostreatus chitosan combined with silver nanoparticles achieving an average zone of 18.2 ± 0.5 mm against Escherichia coli, a 25% increase compared to chitosan alone. Thermal analysis showed improved stability upon silver modification, with endothermic peak shifts from 85 °C to 118 °C. These results demonstrate that fungal-derived chitosan, particularly from P. ostreatus, provides a bioactive matrix with significant antibacterial properties, supporting its potential for biomedical applications. The incorporation of quantitative metrics enhances the robustness and reproducibility of the findings. Full article

This study investigates the simultaneous removal of copper and nickel ions from aqueous solutions using Donnan dialysis (DD), with process optimization performed through Response Surface Methodology (RSM). An initial screening identified the most effective counter-ion, guiding the experimental design toward optimal ion removal. Comparative experiments using Fujifilm Type 1 and Type 2 cation-exchange membranes revealed the superior performance of Type 1 for both metals, as confirmed by FTIR-ATR spectroscopic analysis of membrane morphology. A comprehensive experimental campaign based on a Central Composite Design (CCD) evaluated the effects of copper, nickel, and sodium ion concentrations on removal efficiency. Under optimized conditions—80 mg/L Cu²⁺, 100 mg/L Ni²⁺, and 0.06 mol/L Na⁺—the Fujifilm Type 1 membrane achieved remarkable removal rates of 99.67 ± 0.21% for copper and 98.85 ± 0.34% for nickel. These values were experimentally validated (99.45 ± 0.18% and 98.71 ± 0.27%, n = 3), showing excellent agreement between predicted and observed data and confirming the robustness of the optimized Donnan dialysis process. Overall, the results highlight Donnan dialysis as a highly efficient and environmentally sustainable approach for the removal and recovery of heavy metals from aqueous solutions using Fujifilm cation-exchange membranes. Full article

Advances in next-generation sequencing have significantly improved the molecular diagnosis of mitochondrial diseases (MDs), a group of heterogeneous neurogenetic disorders. However, progress in understanding their pathogenic mechanisms and translating this knowledge into effective therapies remains limited. Elucidating the molecular determinants of phenotypic variability in primary MDs is essential to uncover disease mechanisms and identify novel therapeutic targets. We investigated a cohort of eight adult patients with genetically confirmed Progressive External Ophthalmoplegia (PEO)—an extremely rare mitochondrial disorder—and compared them with eight age- and sex-matched healthy controls. A comprehensive multi-omics approach combining LC–MS/MS-based proteomics, UPLC–MS/MS-based metabolomics, ATR–FTIR spectroscopy, and chemometric multivariate analysis was employed to identify molecular alterations associated with mitochondrial dysfunction. Distinct proteomic and metabolic patterns related to energy metabolism were observed in PEO patients, correlating with their genetic background. Metabolomic analysis showed altered amino acid levels (seven statistically relevant) and disruptions in the metabolism of cysteine, methionine, and glutathione; proteomics finding (154 differentially expressed proteins) revealed dysregulation in extracellular matrix (ECM) organization and immune response pathways. This integrative analytical strategy offers new insights into the molecular complexity of PEO and mitochondrial disorders. The identification of disease-associated molecular signatures may enhance the understanding of pathogenic mechanisms and support the development of improved diagnostic and therapeutic approaches for MDs. Full article

Background: Lycopene is a powerful antioxidant, classified as a carotenoid. Numerous studies confirm its beneficial effects in both the prevention and treatment of various diseases. However, its therapeutic application is significantly limited due to its poor water solubility and low bioavailability from natural sources. Developing a formulation with improved therapeutic characteristics could enhance the effectiveness of lycopene, making it more suitable for medical and nutritional use. The objective of this work was to apply hot-melt extrusion to produce extrudates containing an acetone-based lycopene extract combined with selected polymers, aiming to enhance its dissolution properties. Methods: Lycopene-rich extracts were prepared using ultrasound-assisted extraction with acetone. The obtained extract was processed via hot-melt extrusion together with PVP VA64 and Soluplus. The resulting extrudates were characterized using attenuated total reflectance Fourier-transform infrared spectroscopy (ATR-FTIR) and X-ray diffraction (XRD). Dissolution behavior was assessed using a paddle apparatus, and collected samples were quantified by HPLC. Antioxidant capacity was determined via DPPH radical-scavenging analysis. Results: The polymers PVP VA64 and Soluplus improve lycopene’s dissolution in acidic environments while showing its antioxidant potential. Conclusions: The formulation combining lycopene obtained through hot-melt extrusion with PVP VA64 and Soluplus polymers will enable its wider and more effective application. Full article

Background/Objectives: Fused deposition modeling (FDM) three-dimensional (3D) printing represents an emerging manufacturing platform for personalized oral dosage forms. Its success relies on developing robust drug-loaded filaments with consistent mechanical, thermal, and dissolution properties. This work aims to (i) develop and characterize ketoprofen-loaded filaments using hot-melt extrusion (HME) and (ii) utilize them to fabricate both immediate-release (IR) and sustained-release (SR) tablets via FDM 3D printing. Methods: Filaments were prepared using Kollicoat^® IR and hydroxypropyl methylcellulose (HPMC, 2600–5600 cP) as functional polymers. Sorbitol and sodium lauryl sulfate (SLS) were incorporated as plasticizer and surfactant, respectively. Filaments were evaluated for quality attributes, drug content, tensile strength, and physicochemical and surface characteristics using Scanning Electron Microscopy (SEM), Attenuated Total Reflection Fourier-transform infrared (ATR-FTIR), X-ray Diffraction (XRD), Differential Scanning Calorimetry (DSC) and Thermogravimetric Analysis (TGA). Optimized filaments were fed into an FDM 3D printer to fabricate ketoprofen tablets with varied geometries, shell numbers, and infill densities. Tablets were subjected to USP tests (weight variation, friability, hardness, disintegration, assay, content uniformity), dissolution profiling, and release kinetics modeling. Comparative dissolution studies with market Profenid^® and Bi-Profenid^® tablets were conducted. GastroPlus^® simulations were used for in vitro–in silico correlation. Results: Among the tested formulations, Kollicoat^® IR-based filaments with sorbitol and SLS (F6) demonstrated superior printability, characterized by consistent feeding, stable extrusion, and reliable formation of uniform structures for immediate-release applications. In contrast, HPMC-based filaments with sorbitol (F13) offered the most robust performance for SR formulations. Both exhibited uniform diameter, drug loading, and mechanical strength. IR tablets achieved >80% release within 30 min, while SR tablets prolonged release up to 12 h, following Higuchi and Korsmeyer–Peppas kinetics. All quality attributes complied with USP limits. Market products showed comparable dissolution, validating the approach. GastroPlus^® simulations predicted pharmacokinetic profiles consistent with reported data, supporting IVIVC. Conclusions: This integrated workflow establishes a robust strategy for producing IR and SR ketoprofen tablets from a single FDM platform. The results highlight the feasibility of point-of-care, personalized medicine using 3D printing technologies. Full article

Carbon fibers derived from carbonized and activated polyacrylonitrile (CFPAN) were sequentially brominated and subsequently functionalized with selected primary and secondary amines to engineer a directional electromagnetic (EM) response. Besides bromine incorporation, bromination introduced oxygen-containing surface groups (e.g., carboxyl, lactone), enabling nucleophilic substitution by amines. Surface characterization (SEM-EDS, FTIR ATR) confirmed successful amine grafting, while thermal analysis (TGA, TPD MS) revealed increased weight loss in the 150–450 °C range due to the decomposition of covalently bonded nitrogen- and oxygen-containing moieties, evidencing strong surface functionalization. Microwave characterization in the X-band (8.2–12.4 GHz) demonstrated that functionalization strongly influences the EM response of CFPAN fibers. The measured reflection coefficient varied from −1.0 to −2.5 dB for sulfonylethylenediamine (SuEn)-functionalized fibers and from −2.0 to −4.0 dB for ethylenediamine (En)-treated ones, depending on frequency and fiber orientation. The frequency-averaged absorption coefficient of pure CFPAN amounted to 32–41%, with absorption maxima and minima corresponding to orientations differing by 90°. SuEn modification decreased absorption to 21–35%, while En functionalization enhanced it to 32–51%. Pure CFPAN exhibited the lowest absorption anisotropy (factor 1.28), whereas piperazine- and En-modified samples showed the highest anisotropy (1.57 and 1.59, respectively). Across all compositions, the attenuation constant remained within 1.5–4.5 mm⁻¹. The observed anisotropic behavior is governed primarily by orientation-dependent variations in characteristic impedance and, to a lesser extent, by anisotropic attenuation constants. Such tunable anisotropy is particularly advantageous for EM shielding textiles, where fiber alignment can be tailored to enhance interaction with polarized fields. Among the tested amines, En-functionalized CFPAN exhibited the highest nitrogen content (up to 10.1 at%) and the most significant enhancement in microwave absorption, positioning it as a promising candidate for advanced orientation-sensitive shielding applications. Full article

Benzoxazoles are recognized as significant building blocks in organic synthesis and materials science. This work observed the formation of benzoxazole from o-aminophenol and o-hydroxybenzaldehyde using online ¹H NMR (continuous flow cell, 80 MHz). The identification of changes in the functional group was complemented by ATR-FTIR analysis. Additionally, the kinetic roles of phenylboronic acid and cyanide in the one-pot condensation-cyclization reaction are examined. Real-time monitoring has revealed three observable events: the rapid condensation of the aldehyde and o-aminophenol to produce the imine; the formation of the boron complex in the presence of phenylboronic acid; and the cyanide-assisted cyclization that converts the intermediate into benzoxazole. The findings clarify the transformations that control throughput and provide valuable insights for optimizing reagent loadings under environmentally friendly conditions. Full article

In modern circular-economy value chains, wood is frequently processed into fines, chips, or powders—forms in which anatomical features are no longer visible, rendering traditional visual identification methods ineffective. This study introduces a rapid, non-destructive attenuated total reflection–Fourier transform infrared (ATR-FTIR) spectroscopy approach, combined with chemometric modeling, to address this challenge by enabling both the classification and compositional profiling of processed wood fractions. Using full-spectrum ATR-FTIR data, partial least squares discriminant analysis (PLS-DA) models achieved high-accuracy classification of wood by type, species, and provenance, with sensitivity and specificity reaching up to 1.00. In addition, PLS and backward interval BiPLS models predicted total lignin, acid-soluble lignin, and extractives with strong performance (R² > 0.90, RPD > 2). Interval selection further enhanced prediction accuracy by reducing RMSEP by up to 30%, improving model stability for real-world application. By replacing slow, reagent-intensive wet chemistry with a rapid, green, and scalable technique, the presented methodology provides a valuable tool for authentication, quality control, and resource optimization when dealing with mechanically processed or recycled wood. Full article

The widespread use of methylsulphonylmethane (MSM) as a dietary supplement highlights the need to understand its fundamental behaviour in aqueous solutions. In this paper, we investigate changes in the MSM band shape as a function of its concentration using Attenuated Total Reflection FTIR (ATR-FTIR) spectroscopy. ATR spectra may be complicated by significant optical artefacts arising from refractive index changes. These can be misinterpreted as genuine vibrational shifts, leading to erroneous conclusions. Here, we systematically investigate aqueous MSM solutions using three different internal reflection elements. Applying a rigorous ATR correction procedure, validated by transmission measurements and PARAFAC (Parallel Factor Analysis) analysis, decouples physical phenomena from optical distortions. The corrected spectra reveal a crucial finding: the primary effect of MSM is not a shift in the sulphone band position, but a distinct change in its shape. This result, supported by DFT (Density Functional Theory) calculations, indicates increased heterogeneity of local hydration environments and demonstrates the criticality of proper ATR correction. Full article

Ensuring the quality and safety of agricultural and food products is crucial for protecting consumer health, meeting market expectations, and complying with regulatory requirements. Quality and safety parameters are commonly assessed using chemical and microbiological analyses, which are time-consuming, impractical, and involve the use of toxic solvents, often disrupting the material’s original structure. An alternative technique, infrared spectroscopy, including near-infrared (NIR), mid-infrared (MIR), and short-wave infrared (SWIR), has emerged as a rapid, powerful, and minimally destructive technique for evaluating the quality and safety of food and agricultural products. This review focuses on discussing MIR spectroscopy, particularly Fourier transform infrared (FTIR) techniques, with emphasis on the attenuated total reflectance (ATR) measurement mode (globar infrared light source is commonly used) and on the use of synchrotron radiation (SR) as an alternative high-brightness light source. Both approaches enable the extraction of detailed spectral data related to molecular and functional attributes concerning quality and safety, thereby facilitating the assessment of crop disorders, food chemical composition, microbial contamination (e.g., mycotoxins, bacteria), and the detection of food adulterants, among several other applications. In combination with advanced chemometric techniques, FTIR spectroscopy, whether employing ATR as a measurement mode or SR as a high-brightness light source, is a powerful analytical tool for classification based on attributes, variety, nutritional and geographical origins, with or without minimal sample preparation, no chemical use, and short analysis time. However, limitations exist regarding calibrations, validations, and accessibility. The objective of this review is to address recent technological advancements and existing constraints of FTIR conducted in ATR mode and using SR as a light source (not necessarily in combination). It defines potential pathways for the comprehensive integration of FTIR and chemometrics for real-time quality and safety monitoring systems into the global food supply chain. Full article