Search Results (3,784)

The Activators Regenerated by Electron Transfer Atom Transfer Radical Polymerization (ARGET-ATRP) of vanillin methacrylate (VMA), a bio-based methacrylic monomer derived from vanillin, was systematically studied for the first time. The reaction conditions were optimized aiming at achieving good monomer conversions while preserving the antimicrobial aldehyde functionality. Bipyridine-based catalysts showed limited effectiveness, whereas polydentate aliphatic amines displayed higher activity. Kinetic studies showed linear profiles during the early stages of the polymerization before reaching a conversion plateau accountable to the depletion of the reducing agent, as confirmed by reactivation experiments. The resulting polymer (PVMA) exhibited a glass transition temperature comparable to that of poly(styrene), emerging as a potential bio-derived alternative to fossil-based thermoplastic materials. Furthermore, preliminary in vitro tests demonstrated that PVMA has potential antimicrobial activity against both Escherichia coli (Gram-negative) and Bacillus subtilis (Gram-positive). Full article

Background/Objectives: The Achilles tendon enthesis (ATE) is a key load-transmitting structure that is frequently affected in musculoskeletal disorders, including insertional tendinopathy, overuse injuries and inflammatory enthesopathies. Reliable non-invasive assessment of the enthesis structure is therefore of increasing clinical importance. This study evaluated the ability of advanced magnetic resonance (MR) microscopy to depict the ultrastructural organization of the ATE using histology as a reference standard. Methods: Five human ATEs from anatomical body donations were included. Two specimens were used for protocol development of the histological preparation, whereas three specimens underwent the full multimodal pipeline comprising undecalcified methyl methacrylate (MMA) thin-section histology with Giemsa staining, T2*-weighted 3D-variable echo time (vTE) MR microscopy at 7 Tesla, and microradiography. Results: Histological analysis demonstrated excellent preservation of fibrocartilage zones and mineralized interfaces. Corresponding MR microscopy data allowed the identification of major structural components of the enthesis, particularly mineralized regions, although fine ultrastructural details remained beyond the MR microscopy resolution. Microradiography supported interpretation of the mineralized tissue architecture and MR microscopy signal characteristics. Conclusions: These findings indicate that high-field MR microscopy can capture clinically relevant structural features of the Achilles tendon enthesis, while histology remains essential for detailed ultrastructural validation. The combined imaging approach provides a translational framework that may support improved diagnosis, monitoring and treatment evaluation in musculoskeletal disorders involving the osteotendinous junction. Full article

A polymer electrolyte is developed by integrating a poly(methyl methacrylate) (PMMA)/eutectic electrolyte (EE) phase into a porous polyethylene (PE) scaffold via a solution-casting strategy. In this rigid–flexible coupled architecture, the PMMA matrix serves as a solid host that coordinates with Li⁺ through its polar carbonyl groups, thereby promoting lithium salt dissociation and establishing a stable ion transport network. The incorporated EE, composed of ethylene carbonate and LiTFSI, effectively reduces the glassy rigidity of PMMA and provides continuous pathways for fast ionic conduction. Meanwhile, the porous PE scaffold reinforces mechanical strength and resists lithium dendrite penetration, enabling a thin electrolyte membrane with excellent flexibility. The resulting electrolyte achieves an ionic conductivity of 1.59 × 10⁻⁴ S cm⁻¹ at 30 °C, a lithium-ion transference number of 0.45, and an electrochemical stability window up to 4.75 V. In Li||LiFePO₄ cells, it delivers stable cycling at 3 C for 1000 cycles with 76.8% capacity retention and a Coulombic efficiency exceeding 99.9%. The monomer-free design eliminates residual reactive species that commonly compromise interfacial stability, offering a reliable pathway toward high-voltage solid-state lithium-metal batteries. Full article

This study evaluated the effects of thermocycling on surface roughness (Ra), gloss (GU), color stability (ΔE₀₀), and water sorption of interim materials manufactured by three methods. Disc specimens (n = 20/group) were fabricated from a conventional bis-acryl (PreVISION^® Temp), a computer-aided design/computer-aided manufacturing (CAD/CAM)-milled methacrylate-based composite (StructurCAD Disc^®), and a 3D-printed resin composite (Alias Dental Temp C&B^®). Two disc dimensions were used: 10 × 2 mm for Ra, GU, and color, and 15 × 1 mm for water sorption. Measurements were performed before and after thermocycling (10,000 cycles; 5–55 °C). Nonparametric tests were used (α = 0.05). After thermocycling, Ra increased in the conventional and 3D-printed groups, whereas the milled group demonstrated a decrease (p < 0.05). GU decreased across all groups (p < 0.001) and differed among materials (p = 0.021), with a significant difference only between milled and 3D-printed groups. Color stability differed among materials (p < 0.001): the milled group showed the lowest ΔE₀₀ perceptibility threshold (below PT₀₀ = 0.81), whereas conventional and 3D-printed groups exceeded the acceptability threshold (AT₀₀ = 1.81). Water sorption differed among groups (p < 0.001), with a significant difference between the milled and 3D-printed groups (p < 0.001). The tested 3D-printed material exhibited less favorable post-thermocycling optical properties, whereas the evaluated CAD/CAM-milled material demonstrated more favorable overall surface and optical performance under the applied aging conditions. Full article

This research focused on the development and characterisation of molecularly imprinted polymers (MIPs) modified with titanium dioxide (TiO₂) for the adsorption and photocatalytic degradation of sodium naproxen (NPX). Different percentages of TiO₂ (5% and 25%) were tested and compared to non-imprinted polymers (NIPs). FT-IR analysis confirmed the interaction between methacrylic acid and TiO₂, promoting the formation of specific binding sites and presenting a good imprinting factor. The results showed that the MIP with 5% TiO₂ had the highest adsorption and retention capacity, attributed to the imprinting effect and the reduced interference from TiO₂. The surface of the MIPs is heterogeneous, as it was indicated by the Freundlich isotherm model. The K_F for the MIP with 25% of TiO₂ was higher than for the materials with 5%; values for the MIP/TiO₂ 5% and the NIP/TiO₂ 5% K_F were 4.808 and 4.163 (mg/g)(L/mg)^1/n respectively, while for the MIP/TiO₂ 25% was 6.542 (mg/g)(L/mg)^1/n and for the NIP/TiO₂ 25% it was 2.736 (mg/g)(L/mg)^1/n. Kinetic studies followed the pseudo-second-order model, suggesting more active binding sites in MIPs. Photocatalytic experiments achieved 60% degradation, demonstrating the degradation performance of MIPs; however, this behavior is restricted by the slow degradation of NPX. The materials were evaluated using a water sample (Querétaro River, México); the sample was preconcentrated and analyzed, detecting a concentration of 0.332 mg/L of NPX. This finding highlights the MIPs’ potential application in environmental monitoring and treatment; nevertheless, due to the recalcitrant nature of NPX, MIPs should be used along with other advanced treatment methods to achieve effective removal. Full article

Poly(9,9-di-n-octylfluorene) (PFO) suffers from interchain aggregation, which degrades its blue spectral stability and charge transport. To address this, a series of rod-coil diblock copolymers (PFO-b-PMMAs) with varying poly(methyl methacrylate) (PMMA) chain lengths were synthesized via Steglich coupling. The non-conjugated PMMA blocks act as bulky steric spacers in the solid state, effectively suppressing detrimental PFO aggregation and enhancing pure blue emission stability. Furthermore, moderate PMMA blocks (PFO-b-PMMA1 and PFO-b-PMMA2) promote favorable β-phase formation and ordered crystalline packing. This microstructural optimization yields a maximum electron mobility of 1.98 × 10⁻⁶ cm²/(V·s) for PFO-b-PMMA2, markedly higher than the PFO-2 homopolymer (4.13 × 10⁻⁷ cm²/(V·s)). However, an overlong PMMA block (PFO-b-PMMA3) introduces excessive steric hindrance (T_g = 66 °C) that disrupts crystallization, acting as an insulating barrier that reduces mobility. Thus, precisely tuning the non-conjugated block length effectively maximizes both the blue spectral stability and electron transport capabilities of PFO-based materials. Full article

The thermal drift of microring resonators is one of the key obstacles hindering their practical applications. Employing polymers with negative thermo-optic coefficients to compensate for temperature-induced wavelength shifts represents a common solution. This study utilizes polymethyl methacrylate (PMMA) to counter this effect in silicon nitride microring resonators, achieving thermal drift magnitudes below 2.0 ± 0.1 pm/K within the temperature range of 15 °C to 70 °C. Furthermore, nonlinear thermal drift characteristics were experimentally observed, and simulations revealed that these nonlinearities primarily originate from the temperature-dependent Young’s modulus and Poisson’s ratio of PMMA. This research provides design references for waveguide compensation using negative thermo-optic coefficient materials and proposes a conceptual framework for dual-function devices capable of both athermal operation and thermal tuning. Full article

Background/Objectives: Diabetic wound healing faces significant challenges due to the harsh microenvironment of wounds such as high blood glucose levels, excessive inflammation, persistent infection, upregulated reactive oxygen species (ROS), and damaged new blood vessels. Therefore, developing hydrogel dressings with microenvironmental regulation functions has become an important strategy in treating diabetic wounds. Methods: In this study, an ultraviolet in situ crosslinked hydrogel (D@H/E) was developed using methacrylic anhydride modified hyaluronic acid (HA-MA) and glycidyl methacrylate modified ε-polylysine (EPL-GMA), loaded with the iron chelating agent desferrioxamine (DFO). The physicochemical and biochemical properties of the hydrogel were comprehensively characterized, and its efficacy as a dressing for diabetic wounds was evaluated in a STZ-induced hyperglycemic mouse model. Results: This hydrogel demonstrated remarkable multidimensional effects by alleviating oxidative stress damage, inhibiting bacterial infection, regulating inflammatory responses, mitigating ferroptosis, and promoting cell migration and tubule formation. Specifically, the DFO-loaded hydrogel achieved a high DPPH radical scavenging efficiency of 80.8% and exhibited excellent antibacterial activity, with over 99.8% inhibition against both S. aureus and E. coli. In streptozotocin (STZ)-induced diabetic mice, the hydrogel accelerated wound closure to near completion by day 14. Mechanistically, it significantly upregulated CD206 expression to promote M2 macrophage polarization, upregulated the expression of angiogenesis-related factors to promote angiogenesis at the wound site, and enhanced GPX4 expression to alleviate ferroptosis. Conclusions: By orchestrating multi-dimensional synergy that combines ROS scavenging, infection control, immune regulation, and anti-ferroptosis, this D@H/E hydrogel system effectively remodels the harsh diabetic wound microenvironment, offering a promising platform for chronic wound management. Full article

Conventional adhesives for plywood are mostly derived from petroleum-based materials and commonly suffer from formaldehyde emission, posing threats to the environment and human health. In this study, a renewable resource, Xanthoceras sorbifolium Bunge oil, was used as the raw material. A high-performance bio-based adhesive was successfully prepared by synthesizing Xanthoceras sorbifolium Bunge oil dimethacrylate (MXOEA) as a reactive diluent, blending it with acrylated epoxy Xanthoceras sorbifolium Bunge oil (AEXO), and introducing 2-isocyanatoethyl methacrylate (IEM) to enhance crosslinking. The effects of the MXOEA/AEXO ratio and the IEM addition level on the properties of the adhesive and the resulting plywood were systematically investigated. The results showed that when the mass ratio of AEXO to MXOEA was 3:7, and the IEM content was 10%, the adhesive exhibited the best bonding performance: the resulting plywood achieved a modulus of rupture of 68.85 MPa, a modulus of elasticity of 8086 MPa, and dry and wet bonding strengths of 3.21 MPa and 2.32 MPa, respectively. Mechanistic analysis indicated that the introduction of IEM moderately reduced the viscosity of the adhesive system. Meanwhile, the isocyanate groups in IEM reacted with the hydroxyl groups on the wood surface, forming a chemical crosslinking structure at the adhesive-wood interface, which is considered one of the reasons for the improved mechanical properties of the plywood. This study provides a formaldehyde-free, high-performance bio-based adhesive derived from Xanthoceras sorbifolium Bunge oil for the field of wood-based composites. Full article

The growing accumulation of microplastics in marine environments demands fast and accurate analytical methods for polymer identification. This study presents a new canonical spectral transformation (CST) strategy designed to extract the most relevant information of Raman spectra and enhance the performance of artificial intelligence (AI) models in the classification of microplastics. Using the Marine Plastic Database (MPDB) as the source of Raman spectra, five supervised models—k-Nearest Neighbor (KNN), Random Forest (RF), Extreme Gradient Boosting (XGBoost), Multilayer Perceptron (MLP), and a one-dimensional Convolutional Neural Network (CNN-1D)—were trained and evaluated under both typical (conventional methodology) and CST workflows using 500 noisy samples per category. The CST consists of representing a Raman spectra in a vector where only the magnitude peaks of the most relevant frequency bands of the spectra are retained and the remaining values are null. This CST minimizes the inclusion of non-target data reaching the AI models. All models achieved higher accuracy with CST, where CNN-1D achieved the most significant performance, increasing accuracy to 0.90. In addition, CNN-1D identified Polystyrene (PS) and Poly(methyl methacrylate) (PMMA) with a score of 100% and 99%, respectively. The results demonstrate that CST effectively enhances spectral feature extraction and can be generalized to other spectroscopic techniques, providing a scalable framework for AI-assisted microplastic identification in seawater samples. Full article

Secondary caries and biofilm accumulation remain major causes of failure in provisional crowns and restorations, highlighting the need for multifunctional resin coatings with antibacterial and remineralizing capabilities. This study aimed to develop a novel bioactive and antibacterial resin-based surface coating incorporating 10% dimethylaminododecyl methacrylate (DMADDM), 20% nanoparticles of amorphous calcium phosphate (NACP), and/or 20% calcium fluoride nanoparticles (nCaF₂) within a urethane dimethacrylate/triethylene glycol divinylbenzyl ether (UDMA/TEG-DVBE) matrix. Coatings were evaluated for degree of conversion (DC), flow, shear bond strength, brushing wear resistance (10,000 cycles), and calcium (Ca), phosphate (PO₄), and fluoride (F) ion release up to 70 days. All groups achieved clinically acceptable polymerization, with the lowest DC at 50%. NACP-containing coatings significantly increased shear bond strength to 18.3 ± 2.8 MPa, representing a ~170% increase compared with the experimental control (6.8 ± 2.1 MPa) and exceeding the ISO 10477 minimum threshold of 5 MPa. After brushing simulation, experimental coatings demonstrated low wear depth (0.93–1.19 µm), which was ~40% lower than the commercial control (1.85 ± 0.40 µm). Sustained ion release was achieved for 70 days, with 20% NACP-formula releasing 1.22 mmol/L Ca and 0.90 mmol/L PO₄, while the dual NACP–nCaF₂ formulation provided simultaneous Ca (0.62 mmol/L) and F (0.33 mmol/L) release. The developed coatings demonstrated promising physicochemical properties, bonding performance, wear resistance, and sustained remineralizing ion release, supporting their potential application as therapeutic surface coatings for provisional restorations. Full article

Conventional chemical gel plugging materials often suffer from poor high-temperature stability and inadequate mechanical properties. To address these issues, this study developed a high-performance composite gel material using a multi-component hybrid crosslinking strategy. The material employs γ-methacryloxypropyltrimethoxysilane (MPTMS) as the silica source, which hydrolyzes in situ to generate SiO₂, thereby enhancing temperature resistance. Laponite nanoplatelets are incorporated as a toughening agent and physical crosslinking points, while a self-synthesized reactive microgel (BWL) serves as the organic crosslinking core. Through copolymerization with monomers such as acrylamide (AM) and methacrylic acid (MAA), a triple-crosslinked network structure is constructed. Compared with conventional gels, the synthesized hybrid crosslinked composite gel maintains a high storage modulus and loss modulus after aging at 140 °C and exhibits excellent tensile and compressive properties. Furthermore, the gel was processed into particle-based lost circulation materials with different particle sizes. High-temperature and high-pressure plugging experiments demonstrate that when using a mixed system of 40–60 mesh, 20–40 mesh, and 10–20 mesh gel particles with a total concentration of 2%, it can effectively seal highly permeable sand beds and fractures with apertures up to 5 mm. This meets the engineering requirements for lost circulation materials with high strength and high stability in deep, high-temperature formations. Full article

Background/Objectives: Enteric drug forms are developed to delay drug release to avoid drug degradation in the acidic environment of the stomach or to prevent irritation of the stomach mucosa. The bioavailability of posaconazole (POS) after oral administration depends on stomach pH and food intake. Delayed-release tablets and unmodified oral suspension are the POS formulations currently available on the market. The oral suspension formulation is characterized by highly variable bioavailability, which may significantly affect therapy effectiveness. Methods: In this study, multi-unit drug forms with delayed and sustained POS release were designed. Polymeric microparticles consisting of sodium alginate (ALG), methacrylic acid–ethyl acrylate copolymer (EUD), or both, were prepared using the spray-drying technique. The formulations that met the pharmacopoeia enteric release standards in the in vitro dissolution test were subjected to further in vitro evaluation via swelling and mucoadhesion assays, an antifungal activity test, attenuated total reflectance–Fourier transform infrared spectroscopy (ATR-FTIR), and thermal analysis. Results: It was shown that EUD formulations at concentrations of 5% and 6% provided enteric release, whereas ALG at 1.5% concentration exhibited a sustained, although not delayed, POS release profile. The optimal blended formulations (EAP15–EAP18), comprising 4% EUD with 1.5–2.0% ALG and either 1% or 4% POS, met the pharmacopoeia criteria for enteric dosage forms. Furthermore, these blends demonstrated the most favorable sustained-release profiles in the buffer phase, ranging from 2 to 3 h. The microparticles exhibited beneficial swelling and mucoadhesive properties, which are essential for prolonging contact with the intestinal mucosa; combined with antifungal properties. Conclusions: Obtained carrier may provide a promising preliminary basis for developing a multi-unit, sustained-release enteric dosage form for POS and future in vivo investigations. Full article

Background: The ability of synthetic plastics to persist in the environment and the accumulation of microplastics has intensified the need to explore biological mechanisms capable of interacting with, and possibly degrading, polymeric materials. Microbial enzymes that have extensive catalytic flexibility represent promising candidates in this context. Aim: This study set out to examine the molecular interaction patterns and dynamical stability of Pseudomonas aeruginosa elastase (LasB) with representative structural fragments of typical synthetic plastics to assess the suitability of the enzyme to polymer-derived substrates. Methods: The crystallographic structure of LasB (PDB ID: 1EZM) was retrieved from the Protein Data Bank and pre-prepared with the help of AutoDock4.2.6 Tools. Those polymer-derived ligands that were associated with the major industrial plastics such as polyamide (PA), polyvinyl chloride (PVC), polycarbonate (PC), poly-ethylene terephthalate (PET), polymethyl methacrylate (PMMA), and polyurethane (PUR) were retrieved in the PubChem database and geometrically optimized with the help of the MMFF94 force field. AutoDock Vina, with a specific grid box around the catalytic pocket, including Zn²⁺ ion, was used to perform molecular docking simulations. PyMOL and BIOVIA Discovery Studio software were used to analyze binding conformations, interaction residues and types of intermolecular contacts. Phosphoramidon, a known metalloprotease inhibitor, served as a positive control to confirm the docking protocol. Additional assessment of the structural stability and conformational behavior of the enzyme–ligand complexes was conducted by molecular dynamics (MD) simulations with the Desmond engine and explicit solvent model in a 50 ns trajectory using the OPLS4 force field. RMSD, RMSF, radius of gyration, hydrogen bonding analysis and solvent accessibility parameters were used to measure structural stability. Results: The docking experiment showed varying binding affinities with the test polymers. Polycarbonate (−5.774 kcal/mol) and polyurethane (−5.707 kcal/mol) had the highest in-teractions with the LasB catalytic pocket, polyamide (−5.277 kcal/mol) and PET (−4.483 kcal/mol) followed PMMA and PVC, which had weaker affinities. The following were the important residues involved in interaction networks: Glu141, His140, Val137, Arg198, Tyr114, and Trp115 that were implicated in interaction networks with hydrophobic interactions, π-cation interactions and van der Waals forces that were the major stabilization forces. MD simulations had stabilized complexes, and RMSD values were found to be within acceptable ranges of stability, and ligand-specific changes (around 1.0-3.2 A), which is also in line with stable protein-ligand systems. Phosphoramidon used as a positive control had an RMSD of 1.205 A which is within this stability range. PCA determined various ligand-bound conformational states of LasB with PA in com-pact state, PC and PVC in intermediate states and PUR, PMMA and PET in ex-panded conformations, indicating structur-al stability and adaptability of the binding pocket. Conclusion: These findings show that LasB has a structurally flexible catalytic pocket that can accommodate a wide range of polymer-derived ligands. These results offer an insight into the recognition of enzymes with polymers at the molecular level and also indicate that LasB might help in the interaction of microorganisms with synthetic plastics in environmental systems. Full article

As global oil and gas exploration extends to deep and ultra-deep formations, high-temperature and high-salt environments have become major challenges for drilling fluid viscosifiers. In this study, a hydrophobic associative polymer viscosifier, HATA, was synthesized via free-radical copolymerization using acrylamide (AM), 2-acrylamido-2-methylpropanesulfonic acid (AMPS), sodium styrene sulfonate (SSS), and stearyl methacrylate (SMA) as monomers, and its structure was systematically characterized, while its performance and action mechanism in a 4 wt% bentonite base slurry were evaluated. The results show that the base slurry modified with 3 wt% HATA maintains an apparent viscosity retention ratio of 69.20% following 16 h of hot rolling at 180 °C, with an API filtration loss of only 7.2 mL, and its HTHP filtration loss is 73.72% lower than that of the blank bentonite slurry system; this viscosifier sustains effective viscosity and yield point of the drilling fluid system at 200 °C and in 36 wt% NaCl brine. HATA achieves viscosity enhancement and filtration control by regulating surface charges of bentonite particles, constructing stable three-dimensional networks, and stabilizing clay hydration layers, thus presenting a high-performance viscosifier formulation for high-temperature and high-salinity water-based drilling fluids with important theoretical and engineering application values. Full article