Search Results (1,995)

Industrial wastewater can be reused in other everyday processes to help combat water scarcity worldwide. One contaminant in industrial wastewater is hexavalent chromium, which is highly toxic and can cause kidney, liver, and respiratory problems, making its removal vital. In this study, PLA-based films containing modified zirconia nanoparticles were developed via a solution-mixing process for hexavalent chromium adsorption. Obtaining the films involved two stages: the first was the chemical modification of ZrO₂ nanoparticles with thiamine hydrochloride (vitamin B1) using fixed-frequency ultrasound at an output of 750 W and 50% amplitude for 60 min. The second stage involved preparing the films by mixing them in the solution using an ultrasonic bath. The nanoparticle concentrations were 0.25, 0.5, and 1 wt%. The results obtained from characterization using Fourier-transform infrared spectroscopy (FT-IR) revealed the characteristic bands of PLA and the characteristic peak of the Zr-O bond corresponding to the ZrO₂ nanoparticles. Thermogravimetric analysis (TGA) showed that the ZrO₂ nanoparticles provided thermal stability to the PLA polymer. X-ray diffraction (XRD) showed a broad peak of amorphous PLA at 16.8° and signals corresponding to the crystalline phase of ZrO₂. The morphology of a cross-section of the films was observed using scanning electron microscopy (SEM), revealing a rough surface with pores. Finally, hexavalent chromium adsorption tests were carried out, measuring the adsorption efficiency under the parameters of pH, concentration, and contact time. The PLAZrO₂ sample achieved an adsorption efficiency of 83% at pH 2. Full article

The rapid spread of the invasive brown macroalga Rugulopteryx okamurae has caused severe ecological and economic damage along the European coasts. Efforts to mitigate its impact have been largely ineffective, highlighting the need for alternative strategies to valorise this invasive species. This study explores the use of R. okamurae aqueous extract (RO extract) as a natural reducing and stabilizing agent for the green synthesis of gold (Au@RO), silver (Ag@RO), and platinum (Pt@RO) nanoparticles. The synthesized nanoparticles were extensively characterized using ultraviolet–visible spectroscopy (UV-Vis), transmission electron microscopy (TEM), X-ray diffraction (XRD), zeta potential analysis, and Fourier-transform infrared spectroscopy (FTIR). The results confirmed the successful formation of spherical and stable nanoparticles. Furthermore, the antioxidant activity of the RO extract was determined before and after the synthesis of the nanoparticles by the determination of the reducing power, total phenolic content and 1,1-diphenyl-2-picryl-hydrazyl (DPPH) radical scavenging activity. Notably, Pt@RO showed the highest enhancement in antioxidant activity among the nanoparticles synthesized. The findings demonstrate that R. okamurae can be repurposed as a valuable bioresource for the environmentally friendly production of metal nanoparticles with promising applications. Full article

In this study, the effect of heat stress on the synthesis and the structural and physicochemical properties of exopolysaccharides (EPSs) from Rhodotorula glutinis YM25079 as well as its underlying mechanisms were explored. The results showed that the monosaccharide compositions of the purified YM25079 EPSs produced under normal culture conditions and heat stress (named EPS Y-1 and EPS Y-2, respectively) were consistent. Analyses of ion-exchanged chromatography, Fourier transform infrared spectroscopy and nuclear magnetic resonance spectroscopy suggested that these two EPSs should be dextran, consisting mainly of α-(1→6)-linked glucopyranose units with α-(1→3) branches. Scanning Electron Microscope observed obvious differences in their surface morphologies, with EPS Y-1 showing a smooth, glossy lamellar structure and EPS Y-2 showing an irregular porous structure. According to Atomic Force Microscopy analysis, they formed aggregations with different cohesive structures. EPS Y-2 also had higher molecular weight and thermal stability than EPS Y-1, while EPS Y-1 had better α-amylase inhibitory activity. In addition, transcriptomic analysis unveiled changes in the metabolic pathways related to the uptake and utilization of carbon, nitrogen and phosphor sources, the biosynthesis of steroid and the oxidoreductase activity, as well as the regulatory genes implicated in the EPS biosynthesis under heat stress. Full article

The timely identification of rock fractures is crucial in deep subterranean engineering. However, it remains necessary to identify reliable warning indicators and establish effective warning levels. This study introduces the Acoustic Emission Transformer for FRActure Prediction (AET-FRAP) multi-input time series forecasting framework, which employs acoustic emission feature parameters. First, Empirical Mode Decomposition (EMD) combined with Fast Fourier Transform (FFT) is employed to identify and filter periodicities among diverse indicators and select input channels with enhanced informative value, with the aim of predicting cumulative energy. Thereafter, the one-dimensional sequence is transformed into a two-dimensional tensor based on its predominant period via spectral analysis. This is coupled with InceptionNeXt—an efficient multiscale convolution and amplitude spectrum-weighted aggregate—to enhance pattern identification across various timeframes. A secondary criterion is created based on the prediction sequence, employing cosine similarity and kurtosis to collaboratively identify abrupt changes. This transforms single-point threshold detection into robust sequence behavior pattern identification, indicating clearly quantifiable trigger criteria. AET-FRAP exhibits improvements in accuracy relative to long short-term memory (LSTM) on uniaxial compression test data, with R² approaching 1 and reductions in Mean Squared Error (MSE), Root Mean Squared Error (RMSE), and Mean Absolute Error (MAE). It accurately delineates energy accumulation spikes in the pre-fracture period and provides advanced warning. The collaborative thresholds effectively reduce noise-induced false alarms, demonstrating significant stability and engineering significance. Full article

Myofibrillar protein (MP) aggregation in solutions with NaCl concentrations below 0.3 M results in poor solubility. Ultrasound-assisted glutaminase treatment (UGT) was applied to improve MP solubility in a low-salt solution (containing 0.1 M NaCl). The solubility increased with ultrasonic power and time, peaking at 44.34% (480 W, 15 min) and reaching 61% after UGT. Subsequently, the effect of post-sonication heat treatment (60 °C, 30 min) on the physicochemical and structural characteristics of ultrasound-enzyme treated MP (UEMP), prepared under specific ultrasonic conditions (480 W, 20 min), was systematically investigated. The findings revealed that UEMP exhibited higher hydrophobicity, sulfhydryl content, and turbidity, but reduced particle size, ζ-potential, and fluorescence, suggesting disulfide disruption and exposure of hydrophobic residues. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis revealed weakened high-molecular weight bands and intensified low-molecular weight bands. Fourier-transform infrared spectroscopy confirmed these structural rearrangements, with a blue-shifted amide A band and decreased amide I intensity. Heating further increased the hydrophobicity and fluorescence without altering the size, ζ-potential, or molecular weight. The red shift in the amide A band suggests reinforced local ordering. Rheology analysis showed non-Newtonian shear-thinning behavior, which was unchanged by UGT or heating. Collectively, UGT with moderate heating enhances MP solubility and thermal stability by disrupting stabilizing bonds and modulating the structure. Full article

The postharvest preservation of banana (Musa paradisiaca) is essential to maintain fruit quality and minimize losses during storage and export. Packaging films play a critical role in protecting fruit from mechanical damage and environmental stress. This study compared the physicochemical and mechanical properties of two commercial polyethylene films—high-density polyethylene (HDPE) and low-density polyethylene (LDPE)—under controlled postharvest conditions (13 °C, 95% RH). Films were characterized using Differential Scanning Calorimetry (DSC), Fourier Transform Infrared Spectroscopy (FTIR), Thermogravimetric Analysis (TGA), and Flame Atomic Absorption Spectroscopy (AAS), while tensile testing evaluated mechanical performance. HDPE exhibited greater melting stability (+8%), relative crystallinity (+12%), and tensile strength (+15%) compared with LDPE, which presented higher flexibility. HDPE contained trace zinc (0.82–0.94 mg/100 g), whereas LDPE was zinc-free. Both polymers retained their polyethylene fingerprint without oxidative degradation, confirming structural integrity under cold storage. The TGA data verified the absence of thermally unstable additives rather than operational degradation, supporting material homogeneity. Overall, HDPE demonstrated superior stability and durability for banana packaging applications, highlighting the relevance of integrated polymer diagnostics for safe and sustainable postharvest systems. Full article

Phase change materials (PCMs) are widely used for thermal energy storage; however, improving their thermal stability and minimizing supercooling effects remain important challenges. This study addresses these issues by synthesizing and characterizing new microencapsulated MCPs (microPCMs) that incorporate beeswax (BW), a sustainable biological source derived from animals, thus reducing the use of paraffins from petroleum resources, as the main material and calcium carbonate (CaCO₃) as the shell to improve overall performance. MicroPCMs with variable shell contents (20%, 40%, 60%, and 80%) were prepared and analyzed using Fourier Transform Infrared Spectroscopy (FTIR), X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), particle size distribution analysis (PES), and differential scanning calorimetry (DSC) to evaluate their structural, morphological, and thermal properties. The results reveal that microPCMs exhibit a spherical morphology and robust core–envelope integrity, with thermal energy storage capacities ranging from 121.39 to 122.22 J/g, compared to 137.62 J/g for pure beeswax. In addition, the composites demonstrated reduced supercooling and stable thermal performance during repeated cyclic tests. This work introduces the use of calcium carbonate shells combined with a natural beeswax core to create environmentally friendly microPCMs with enhanced thermal stability and reduced supercooling, offering a sustainable alternative for efficient thermal energy storage. Full article

A compact offset-coupled hybrid fiber interferometer (OCHFI) is designed and experimentally demonstrated for simultaneous measurement of salinity and temperature. The sensor integrates multimode fiber (MMF) and offset no-core fiber (NCF) through an intermediate single-mode fiber (SMF), producing distinct interference patterns for multi-parameter sensing. The optimal SMF length was determined through COMSOL simulations (version 6.2) and fixed at $50 \mathrm{c}\mathrm{m}$ to achieve stable and well-separated interference dips. Fast Fourier Transform analysis confirmed that the modal behavior originates from the single-mode-multimode-single-mode (SMS) and single-mode-no-core-single-mode (SNS) segments. Experimentally, Dip 1 exhibits salinity sensitivity of $0.62206 \mathrm{n}\mathrm{m}/\mathrm{‰}$, while Dip 2 shows temperature sensitivity of $0.09318 \mathrm{n}\mathrm{m}/°\mathrm{C}$, both with linearity ($R^2 > 0.99$), excellent repeatability, and stability, with fluctuations within $0.15 \mathrm{n}\mathrm{m}$ over 60 min. To remove cross-sensitivity, both the transfer matrix method and an Artificial Neural Network (ANN) model were employed. The ANN approach significantly enhanced prediction accuracy ($R^2 = 0.9999$) with RMSE improvement approximately 539-fold for salinity and 56-fold for temperature, compared with the analytical model. The proposed OCHFI sensor provides a compact, low-cost, and intelligent solution for precise simultaneous salinity and temperature measurement, with strong potential for applications in marine, chemical, and industrial process control. Full article

Background/Objectives: Flavonoids have been extensively investigated as reducing and stabilizing agents in the green synthesis of metallic nanoparticles. However, studies specifically employing pure naringin (NG) and naringenin (NGN) remain relatively scarce. Methods: In the present work, silver nanoparticles (AgNPs) were synthesized under controlled laboratory conditions using NG and NGN as bioreductants, and critical parameters governing nanoparticle formation were optimized. The synthesized AgNPs were comprehensively characterized using ultraviolet–visible (UV–Vis) spectroscopy, dynamic light scattering (DLS), scanning transmission electron microscopy (STEM), energy-dispersive X-ray spectroscopy (EDX), and Fourier-transform infrared spectroscopy (FTIR). Results: The characterization analyses confirmed the successful formation of predominantly spherical AgNPs with average particle sizes of 17 nm (AgNG) and 20.4 nm (AgNGN). DLS analysis indicated zeta potentials of approximately −30 mV and PDIs of 0.45 (AgNG) and 0.29 (AgNGN), consistent with stable colloidal dispersions. Biological evaluations revealed that both AgNP systems exhibited notable antioxidant and antimicrobial activities. Furthermore, cytogenetic assessment using the Allium cepa assay demonstrated concentration-dependent alterations in mitotic index and chromosomal integrity, indicating biological activity at cellular level. Conclusions: Collectively, these results underscore the potential of flavonoid-mediated synthesis as an eco-friendly and effective approach for generating stable, bioactive nanomaterials with promising biological applications. Full article

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

Background/Objectives: Rutin, a bioactive flavonol glycoside known for its antioxidant, anti-inflammatory, and anticancer activities, faces limited clinical application due to its poor aqueous solubility and low oral bioavailability. This study aimed to enhance the dissolution of rutin by preparing solid dispersions (SDs) using a fluid-bed coating system and formulating the resulting SDs into tablet dosage forms. Methods: Rutin was dissolved in methanol and sprayed onto various carriers, including lactose monohydrate, mannitol, microcrystalline cellulose, silicon dioxide, and calcium carbonate. Results: Among the carriers tested, lactose monohydrate produced the highest dissolution enhancement, achieving complete drug release within 15 min versus approximately 60% for free rutin. Further investigation into the effect of the rutin-to-lactose ratio on dissolution enhancement identified 1:10 as the most effective. Characterization by powder X-ray diffraction (PXRD) and differential scanning calorimetry (DSC) confirmed a marked reduction in rutin crystallinity, while scanning electron microscopy (SEM) revealed reduced particle size and successful adsorption onto the carrier. Fourier transformed infrared (FT-IR) analysis suggested hydrogen bonding interactions between rutin and lactose monohydrate, which contributed to improved dissolution. The optimal SD was incorporated into tablets containing 50 mg of rutin via wet granulation, and the inclusion of sodium lauryl sulfate further enhanced dissolution. Stability testing demonstrated that the optimized tablets maintained their dissolution profile after 6 months under accelerated conditions (40 °C and 75% RH). Conclusions: These findings indicate that fluid-bed coating is an effective approach for preparing SDs to improve the dissolution of rutin and may be extended to other natural polyphenolic compounds. Full article

One of the approaches to increase bioavailability and stability of hydrophobic biologically active compounds is their incorporation into polymer backbone. This work deals with the modification of chitosan (CS) with gossypol (GS), a phenolic compound with confirmed anticancer properties, by the free-radical grafting method. The series of the CS derivatives with increasing content of GS were prepared using pure GS or gossypol acetate (GSA) and compared to the control CS (cCS). The starting CS, cCS, and GS-containing derivatives were characterized using Fourier-transform infrared (FTIR), Raman, and ¹³C ssNMR spectroscopies; elemental and thermogravimetric analysis to evaluate the influence of the radicals and GS on the properties of polymers was performed. The Folin–Ciocalteu (F-C) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) methods were used to evaluate antioxidant properties of GS-modified CSs. Additionally, the polymer solubility and the specific viscosity of the solutions were determined. The content of GS in polymers raised proportionally with increasing amount of GS added to the reaction mixture, thereby enhancing the ability to scavenge free radicals. The type of GS used (GS or GSA) in polymers affected the degree of CS crosslinking (higher for pure GS), polymer solubility (lower for pure GS), the amount of grafted GS (~20% higher for GSA), and antioxidant properties in favor of GSA. Full article

Cowhide collagen (CC) is a valuable by-product of the meat industry with promising applications in food systems; however, its poor viscosity and limited stability restrict its practical use. This study systematically investigated the interactions between CC and three representative polysaccharides—xanthan gum (XG), gellan gum (GG), and chitosan (CS)—under varying concentrations, pH, and ionic strengths. The physicochemical behaviors of the composite systems were evaluated through turbidity, fluorescence spectroscopy, Fourier transform infrared (FTIR) analysis, and rheological measurements. The experimental results revealed a pronounced increase in the turbidity of the GG–CC system, rising from approximately 0.18 ± 0.01 to 2.14 ± 0.01 as the polysaccharide concentration increased, with maximum values exceeding 2.0 under several conditions. Similarly, both the apparent viscosity and turbidity of the other two PS–CC composite systems exhibited a marked and progressive enhancement with increasing polysaccharide content. FTIR spectra confirmed strengthened O–H stretching and amide I shifts, indicating intensified hydrogen bonding and electrostatic interactions. High NaCl levels disrupted the protein hydration shell, modifying fluorescence intensity and peak sharpness. XG–CC and GG–CC composites exhibited similar behaviors, while CS–CC systems showed opposite pH-dependent trends due to cationic–cationic repulsion. Overall, polysaccharide type and concentration exerted stronger effects on CC structure and rheology than environmental factors. These results clarify how polysaccharide type and environmental factors modulate collagen–polysaccharide interactions and provide practical guidance for selecting polysaccharides and processing conditions to tailor the rheological and stability properties of collagen-based food ingredients. Full article

The agrifood sector produces considerable waste, offering opportunities for sustainable innovation. In the coffee industry, spent coffee grounds (SCG) can be valorized to generate eco-friendly nanomaterials such as nano zerovalent iron (nZVI), widely applied in soil and water remediation. In this study, green nZVIs were synthesized using SCG hydromethanolic extracts and FeCl₃, subsequently characterized, and assessed for cytotoxicity. High-performance liquid chromatography with diode-array detection (HPLC-DAD) was employed to identify hydroxycinnamic acids, caffeine, and trigonelline in the SCG extracts. Preliminary remediation assays were conducted with seven contaminants, with venlafaxine selected for detailed pH and kinetic studies. Characterization of nZVIs included SEM and EDS analyses, which revealed spherical nZVI particles (72–83 nm) composed of carbon (47%), oxygen (34%), and iron (16%). Dynamic light scattering (DLS) measurements indicated the presence of smaller particles (15–23 nm). Thermogravimetric analysis (TG) confirmed a residual mass of about 20% at 1400 °C. Fourier-transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) confirmed phenolic compound incorporation, while X-ray diffraction (XRD) revealed an amorphous structure. The particles exhibited magnetic behavior and showed no cytotoxicity toward MRC-5 and U87 cell lines. Among the tested contaminants, venlafaxine displayed the highest removal efficiency in remediation tests. Compared with chemically synthesized nZVI, the green version exhibited enhanced stability, attributed to the presence of surface-bounded organic matter. Overall, this sustainable and cost-effective approach to produce nZVI from SCG provides an innovative method for waste valorization and environmental remediation. Full article

Evaluation of characteristics and flocculation mechanisms of microbial flocculants facilitates the identification of potential applications and informs the fine-tuning of operational conditions for maximum activity. Therefore, this study aimed to characterise and optimise the operational conditions of bioflocculants produced from Klebsiella pneumoniae and Meyerozyma guilliermondii for potent wastewater treatment. Scanning electron microscopy, X-ray Diffraction (XRD), Thermogravimetric Analysis (TGA) and Fourier Transform Infrared Spectroscopy (FTIR) were employed to assess the surface morphology, crystalline structure, thermal stability, and functional group composition of the bioflocculants. Their cytotoxicity was assessed using the tetrazolium bromide-based assay against human colorectal adenocarcinoma (CaCO-2) cell lines. Flocculation efficiencies and mechanisms were determined using Jar and zeta potential assays, respectively. The bioflocculant from K. pneumoniae (Kp1) revealed a fibrous morphology, whereas that from M. guilliermondii (Mg1) displayed a granular structure. FTIR spectra revealed hydroxyl, amine, and alkene groups as key functional groups, while TGA analysis indicated that Kp1 was thermally unstable, contrary to Mg1, which exhibited good thermal stability. Bioflocculants Kp1 and Mg1 exhibited COD removal of 90.86% and 93.12% and turbidity reductions of 92.65% and 92.74%, respectively. Zeta potential analysis revealed that bioflocculant Kp1 primarily flocculated through charge neutralisation, while Mg1 employed a bridging mechanism. These bioflocculants illustrated strong potential to treat wastewater. However, the observed cytotoxic effect at increased concentrations warrants cautious handling and application in lower doses. Full article