Search Results (2,118)

Textile industry wastewater poses a significant environmental challenge due to the presence of persistent dyes. Cationic dyes are characterized by resistance to the conventional coagulation method. The appropriate properties and combination of chemicals guarantee an effective removal process. This study explains the effect of modification of methylene blue solution by the addition of a natural biopolymer—hydrolyzed tannic acid (TA). The study assumed that a combination of tannic acid, methylene blue and polyaluminum chloride would provide a synergistic effect and significantly improve the coagulation and sediment filtration process. Coagulation tests were carried out for a range of methylene blue concentrations. The optimal arrangement of solution components and coagulant doses was selected and tested. Over 95% dye removal efficiency was achieved. The maximum dye removal efficiency was determined to be 5 mg/mg Al at pH = 5.0. Based on the analysis of UV-VIS spectroscopy, FTIR and electrokinetic potential, changes in the solutions of tannin-modified dyes and their effect on the precipitation of flocs and the nature of sorption were determined. The main phenomena affecting the removal mechanism are discussed. The results indicate that tannic acid can serve as a sustainable coagulant aid, supporting the development of technologies for treating cationic-dye-laden wastewater. Full article

This study addresses several key limitations identified in previous research on additively manufactured PLA composites. Unlike most earlier studies that focused primarily on the characterization of as-printed materials, the present work systematically investigates both mechanical and surface behavior before, during, and after artificial aging. In addition, six different printing configurations and reinforcement types (PVC and fiberglass mesh) were analyzed under controlled conditions, enabling a more reliable assessment of their combined influence on composite performance. Printed specimens were artificially aged for 45 and 90 days. The aging protocol combined cyclic changes in moisture, temperature, UV, and IR agents, trying to mimic real exploitation conditions as realistically as possible. The chemical and surface changes during aging were tracked using FTIR spectroscopy, colorimetry, contact angle, and surface free energy measurements. Mechanical performance at 0, 45, and 90 days was evaluated through tensile, three-point bending, and Charpy impact tests, as well as full-scale cantilever loading tests of real printed drone arms. Results show that artificial aging causes measurable chemical and surface modifications, as indicated by changes in the FTIR degradation index and surface wettability. However, these changes do not result in severe mechanical degradation within the investigated aging period. Reinforcement in the form of incorporated PVC and fiberglass mesh significantly affected failure behavior. Specimens printed with higher infill density and thicker infill lines generally exhibit improved mechanical properties. Specimens stiffness and impact resistance were also altered. Results demonstrate that reinforced PLA structures are suitable for lightweight drone applications. Full article

Silver nanoparticles (AgNPs) are widely recognized for their potent antibacterial properties and diverse biomedical applications. While conventional synthesis methods typically rely on chemical-reducing agents that may pose risks to human health and the environment, this study proposes an eco-friendly green synthesis approach utilizing porcine skin extracts. The extracts were prepared through thermal treatment and filtration to serve as a biological reducing agent. Successful synthesis was validated using dynamic light scattering, Fourier transform infrared (FTIR) spectroscopy, UV–Vis spectroscopy, and scanning electron microscopy (SEM). Furthermore, the antimicrobial efficacy of the synthesized AgNPs was evaluated against multidrug-resistant microorganisms, demonstrating significant growth inhibition across various antibiotic-resistant strains. These findings suggest that porcine skin—a readily available bioresource—is a promising precursor for the sustainable production of AgNPs with broad-spectrum antimicrobial potential. Full article

In this work, poly(acrylic acid)-based layers were injected to form a sandwich layer between the cationic and anionic species for a compact and effective fire-retardant coating on cotton fabric using the layer-by-layer coating technique. From the SEM analysis, as the number of tri-layers increases, the attachment intensity increases, as can be seen for poly(acrylic acid) chitosan and bentonite clay PCB-5TL (the highest tri-layers), while in the case of halloysite-based coatings, as the number of tri-layers increases, instead of attachment, the agglomeration increases due to the high surface area of halloysite nanoclay tubes. FTIR and UV confirmed the finding from the new peak entry and an increase in thickness. The highest thermal residue, ~18%, was obtained for poly(acrylic acid) chitosan and halloysite nanoclay PCH-5TL with a maximum degradation peak intensity at ~389 °C. From the flammability and after-burning SEM investigation test, it was observed that the halloysite-based coating with a higher number of layers offered higher resistance against the flame spread and ignition and, thus, produced a higher amount of char. Full article

Background/Objectives: Gastro-resistant multiparticulate systems are designed to protect drugs in acidic environments and to ensure intestinal release. In practice, the method of administration may need to be modified: pellet-containing capsules opened or tablets halved for patients with swallowing difficulties, yet the type of liquid used for administration is often not specified. This study examined the stability of gastro-resistant coated pellets after exposure to various aqueous media prior to ingestion. Methods: To evaluate administration instructions, 103 Summaries of Product Characteristics of gastro-resistant products were reviewed. Pellets were produced using a bottom-spray fluidized bed process and coated with Eudragit L 30 D-55. Dissolution testing in pH 1.2 medium was performed after pre-soaking the pellets for 5, 15, and 30 min in beverages with various pH and conductivity. Drug release was measured by UV-VIS method, and morphological changes were assessed by image analysis. Marketed gastro-resistant products were also examined visually. Results: SmPC review revealed that the beverage for intake was frequently unspecified. Among the tested beverages differences in pH and conductivity were observed. Alkaline medicinal mineral waters induced increased and time-dependent premature drug release compared to tap and filtered water. Image analysis indicated a reduction in surface area after exposure to alkaline media. Conclusions: Contact with non-specified aqueous media before swallowing may weaken the protective function of gastro-resistant films. More explicit recommendations on suitable administration manipulation and media may improve therapeutic consistency. Full article

Expanded polystyrene (EPS) waste is a major environmental concern, yet practical routes to upgrade it into higher value-added materials remain limited. Here, post-consumer EPS was dissolved in ethyl acetate and solvent-cast into films containing cellulose nanocrystals (CNCs) and a sunflower oil. Three formulations were produced: F-EPS (100% EPS), F-EPS + CEL (80% EPS/20% CNC), and F-EPS + CEL + OIL (80% EPS/15% CNC/5% oil). CNC markedly enhanced optical shielding, reducing transmittance at 400 nm from ≈58% (F-EPS) to ≈18% (CNC containing films). All films remained hydrophobic, showed negligible water uptake, and exhibited low mass loss after 30 days of accelerated weathering ($\Delta M=1$–$3\%$). Tensile testing showed that F-EPS had the highest UTS and elongation at break (10.0 ± 0.6 MPa and 10.5 ± 0.4%), whereas adding cellulose increased the elastic modulus (249.5 ± 29.0 MPa to 358.4 ± 64.8 MPa) but reduced UTS and elongation (8.2 ± 0.2 MPa and 5.4 ± 2.5%). Oil addition led to a further reduction in UTS and elongation (6.2 ± 0.4 MPa and 3.6 ± 0.0%), while the modulus returned to a value statistically similar to neat F-EPS. FTIR and XRD confirmed preservation of the EPS chemical fingerprint and a predominantly amorphous structure ($2\theta \approx 20$–30°). Overall, EPS + CNC + OIL films combine hydrophobicity, UV-screening, and elastic modulus similar to neat F-EPS, supporting their use as moisture-resistant, UV screening protective topcoats for non-food-contact paperboard packaging. Full article

To address the low utilization rate of straw and environmental pollution caused by traditional processing methods, this study developed a novel composite material based on straw for manufacturing outdoor furniture. Designed to achieve high-value recycling of agricultural waste and enhance the durability and sustainability of outdoor materials, the straw is treated with alkali and processed using an MDI curing system, with the addition of ZnO to enhance functional properties. Characterization of material properties was performed using contact angle measurements, UV-visible spectroscopy, and mechanical testing. The results indicate that a water contact angle of 93.51° was achieved for the composite material at a ZnO content of 6 wt.%, demonstrating excellent hydrophobicity. The introduction of ZnO reduced light absorption, indicating that the material exhibits superior stability in interior and exterior environments. The synergistic interaction between ZnO and straw fibers, along with the resulting active free radicals (·OH), endows this material with hydrophobic and UV-resistant properties. This composite material combines excellent mechanical strength with environmental friendliness, offering broad prospects in the field of sustainable outdoor furniture manufacturing. Full article

Temperature control and crack prevention are crucial for mass concrete structures in cold regions. Electrically conductive roller-compacted concrete (ERCC) provides a promising route to shift surface temperature regulation from passive protection to active control. To develop an ERCC material suitable for engineering applications, this study first established a quantitative relationship between interparticle interaction energy and particle spacing to elucidate the effect of carbon black (CB) dispersion and agglomeration on concrete performance. The dispersion quality of CB was then evaluated by sedimentation tests, UV absorbance, and resistivity measurements. The absorbance of CB suspensions containing PCE, SDS, and TA increased by 79.9%, 80.1%, and 100.4%, respectively, compared with the suspension without dispersant, and TA gave the lowest mortar resistivity. Mechanical tests and mesoscopic simulations showed that coarse aggregate volume fraction and CB dosage had stronger effects on the compressive strength and elastic modulus of ERCC than aggregate gradation and specimen size. After calibration using the ERCC-2-TA mixture, the average errors between simulation and experiment were 0.7% for compressive strength and 0.4% for elastic modulus. For engineering applications, the recommended ERCC parameters were a coarse aggregate volume fraction of 40%, a CB content of 4–5% and a water-to-binder ratio of 0.45–0.50 for roads, and a CB content of 8% with a water-to-binder ratio of 0.55 for dams. Full article

The two-spotted spider mite, Tetranychus urticae Koch, is a major agricultural pest that causes economic losses in the cultivation of most crops worldwide. Pesticide resistance and the phase-out of many active pesticidal substances have accelerated research into alternative methods for pest management. The effects of light-emitting diodes (LEDs) on plants, as well as their potential use in pest management, have attracted the attention of researchers for the last 25 years. In this study, the repellent effects of UV-A, blue, and red LEDs on T. urticae were investigated using choice tests in laboratory conditions. The lethal effect of red LED light on adult individuals was determined by a no-choice test. Importantly, red LED caused 67.0 ± 4.5% (mean ± SE) mortality in adults in the no-choice test. Second, the UV-A LED clearly had a strong repellent effect on T. urticae in the choice tests. In the “UV-A vs. white LED” and “UV-A vs. darkness” choice tests, the egg-laying percentage in the UV-A part remained below 0.55%. Furthermore, UV-A also had a significant repellent effect on T. urticae larvae. In the choice tests, the larval ratio in the UV-A part was less than 5%. The results of laboratory experiments indicated that red and UV-A LEDs have significant lethal and repellent effects on T. urticae. Comprehensive investigations should be performed in greenhouses using different strategies to optimize how these potential effects can be used in pest management. Full article

An eco-friendly green synthesis approach was employed to produce copper nanoparticles (CuNPs) using a polyherbal extract derived from two medicinally important plant species, Hygrophila auriculata (Schumach.) Heine and Leucas aspera (Willd.) Link. The plant extracts were initially subjected to phytochemical screening to identify bioactive constituents potentially involved in nanoparticle synthesis. The synthesized CuNPs were characterized using UV-visible spectroscopy, Fourier-transform infrared spectroscopy (FTIR), gas chromatography–mass spectrometry (GC-MS), field-emission scanning electron microscopy coupled with energy-dispersive X-ray analysis (FESEM-EDAX), X-ray diffraction (XRD), and thin-layer chromatography (TLC). UV-visible spectroscopy revealed a characteristic absorption peak at 233.6 nm. FTIR analysis indicated the presence of functional groups associated with nanoparticle reduction and stabilization, whereas FESEM imaging showed predominantly spherical particles with sizes ranging 63–68 nm. Elemental composition was confirmed using EDAX analysis. XRD analysis demonstrated polycrystalline nature of the CuNPs, with an average crystallite size of 11.5 nm. GC-MS analysis and phytochemical screening further confirmed the presence of bioactive compounds, whereas TLC analysis revealed differences in mobility between the plant extract and synthesized CuNPs. Antibacterial activity of the synthesized CuNPs was evaluated using the agar well diffusion method against clinically relevant bacterial strains, including those of Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, and Streptococcus pyogenes. The polyherbal-derived CuNPs produced larger inhibition zones than the individual plant extracts, particularly against multidrug-resistant pathogens such as P. aeruginosa and S. aureus. Additionally, the nanoparticles exhibited concentration-dependent antioxidant activity in the 2,2-diphenyl-1-picrylhydrazyl assay at concentrations ranging 10–50 mg/mL, with radical scavenging activity increasing from 29.9% to 76.5% and a corresponding decrease in absorbance from 0.698 to 0.234 (p < 0.05). Cytotoxic evaluation in HepG2 cells after 48 h of exposure demonstrated dose-dependent morphological changes and reduced cell viability. These findings suggest that polyherbal-derived CuNPs possess antibacterial, antioxidant, and cytotoxic properties with potential relevance for biomedical applications. Full article

To promote the application of natural dyes in eco-textiles and develop multifunctional silk fabrics, this study optimized the extraction of functional pigments from rhubarb and investigated their dyeing performance and functional properties on silk. The optimal extraction conditions were determined as pH 11, 80 °C, 50 min, with three extraction stages. The optimized direct dyeing parameters for silk fabrics were: dye bath pH value of 7, bath ratio of 1:40, dye solution concentration of 5%, and dyeing at 80 °C for 60 min. Post-dyeing metal ion mordanting significantly regulated the hue and dyeing depth of fabrics, with ferrous sulfate mordanting demonstrating the most ideal effect, enabling fabrics to exhibit deep gray coloration and a substantial increase in K/S value. The dyed silk exhibited significantly enhanced Ultraviolet (UV) protection (UPF 18.72 for direct dyeing, reaching 29.80 after Fe²⁺ mordanting) and antibacterial activity (inhibition rates of 69.26% and 77.49% against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus), respectively, exceeding 95% after Fe²⁺ treatment). This work demonstrates that rhubarb dyeing can produce functional silk with excellent UV-blocking and antibacterial properties, supporting its potential in ecological textiles. Full article

In this paper, a 1.1 THz staggered double-grating slow-wave structure (SWS) for traveling wave tubes (TWTs) is fabricated using UV-LIGA processes based on RD-2150 photoresist. The designed SWS has a wide side of 170 μm and a narrow side of 50 μm, and when half of the SWS is fabricated, the height of the structure is 85 μm, which is half of the wide side. The fabrication process includes lithography, electroforming, grinding, polishing, and resist removal. The top surface, bottom surface, and sidewall roughness of the as-fabricated structure were measured to be 21 nm, 20 nm, and 17 nm. The mean measured sidewall verticality of the structure was 90.1°, with a standard deviation of 0.5° obtained from four independent sampling positions. For the structure’s nominal dimensions of 85 μm in height and 50 μm in width, the achieved dimensional accuracies were ±2 μm and ±1 μm, with corresponding standard deviations of 1.05 μm and 0.59 μm, respectively, confirming excellent structural uniformity. We subsequently evaluated the impact of these dimensional deviations on the electromagnetic performance of the structure. The results indicate that the deviations had a negligible effect on the dispersion characteristics. Specifically, the linewidth deviation led to a 21% reduction in coupling impedance, while the height deviation caused a 600 V increase in the synchronous operating voltage. Full article

Developing materials that simultaneously exhibit bulk elasticity and a durable, self-renewing surface is a persistent challenge, as traditional fillers often impair flexibility and sacrificial coatings fail under repeated strain. This paper presents an innovative thiol–ene/polyurethane hybrid system, fabricated via a sequential thermal–UV curing process, which decouples the properties of the highly elastic bulk from those of the robust surface layer. The resulting bulk elastomer achieves an outstanding combination of high strength (20.9 MPa) and exceptional extensibility (990% elongation at break). Crucially, the UV-crosslinked surface forms a dense, abrasion-resistant shield that reduces friction-induced mass loss by 81% compared to the bulk material. This surface layer also exhibits a unique self-renewing capability, effectively restoring its protective function over at least three abrasion cycles and reducing mass loss by 57% after the first recovery cycle relative to an unprotected control. Dynamic mechanical analysis validates the distinct dual-network structure, evidenced by two well-separated glass transition temperatures, which underpin the material’s pronounced shape memory effect. This work provides a design paradigm for creating flexible and durable polymer systems with independently tailored bulk and surface properties, offering significant potential for applications in artificial skin and demanding flexible components. Full article

Background/Objectives: Teucrium polium L. is widely used in traditional medicine and has been proposed as a source of antimicrobial adjuvants in the context of antimicrobial resistance. Here, we characterized the essential oil (EO) and polar extracts of T. polium and evaluated their antioxidant activity, antimicrobial potency against clinical multidrug-resistant (MDR) isolates, and the interaction of the EO with conventional antibiotics using a chequerboard assay (FICI); further, we investigated in silico molecular interactions with some targets related to resistance. Methods/Results: The EO, which was hydrodistilled and subsequently analyzed by GC–MS, is characterized by dominant limonene content (24.13%) and contents of oxygenated sesquiterpenes such as β-eudesmol (10.48%) and α-muurolol (8.10%). HPLC/UV–ESI–MS characterization of the extracts (decoction and Soxhlet) demonstrated that they were rich in polyphenolic compounds and flavonoids, which matched the standard phytochemical characteristics of this species. The extracts exhibited significant reducing capabilities, and the hydroethanolic extract exhibited the highest antioxidant activity (DPPH IC₅₀ = 15.41 μg/mL; FRAP EC₅₀ = 30.65 μg /mL), while the EO revealed at most moderate capacity in these tests. In antimicrobial assays, the EO inhibited fungi more effectively than the extracts (MIC of 1.17 mg/mL against Aspergillus niger; 4.69 mg/mL against Candida spp.), while antibacterial MICs for both the EO and extracts were generally high (up to 50 mg/mL). Combination testing nevertheless identified synergistic or additive effects of the EO with selected antibiotics, notably with ceftazidime against ESBL-producing Escherichia coli (FICI = 0.141) and Staphylococcus aureus (FICI = 0.039) and with amikacin against Klebsiella pneumoniae (FICI = 0.313); the EO–ceftriaxone pairing against ESBL E. coli was additive (FICI = 0.516). Docking simulations further supported these observations by showing the favorable predicted binding of oxygenated sesquiterpenes, most notably β-eudesmol and α-muurolol (up to −8.6 kcal/mol), to resistance-related targets such as RND efflux pumps, β-lactamases, and porins. Conclusions: Taken together, the in vitro and in silico data suggest that T. polium could be explored as a natural antimicrobial option and as an adjuvant to enhance antibiotic activity against multidrug-resistant pathogens. Full article

Modern bioimplants increasingly depend on surface-engineered functionality to elicit adaptive biological responses. One promising strategy involves the electrodeposition of bioresponsive elements such as magnesium (Mg), which plays a critical role in osseointegration. In this study, we present a novel approach for modifying anodized zirconia nanotubes (ZrNTs) via Mg decoration using electrochemical deposition. A controlled pulsed cathodic linear sweep protocol was employed to control Mg deposition behaviour, enabling reduced clustering and improved spatial distribution. Notably, ultraviolet (UV) irradiation was found to influence Mg adsorption dynamics, revealing a distinct pattern of interaction. Comprehensive surface characterization was conducted to assess nanotube morphology, Mg adherence, and distribution. These modified surfaces were subsequently evaluated for their potential in further functionalization, targeting surface chemistries conducive to biomaterial viability. The biomineralization capacity of Mg-decorated ZrNTs was systematically investigated using electrochemical impedance spectroscopy (EIS) and Tafel analysis, demonstrating enhanced apatite formation and improved corrosion resistance. This work establishes Mg decoration of ZrNTs as a viable route for developing bioactive, corrosion-resistant implant surfaces. Full article