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To evaluate and compare the surface roughness and optical properties in resinbased CAD/CAM materials during thermal aging. Methods: Lava Ultimate HT (3M ESPE, USA) and VITA Enamic HT (Vita Zahnfabrik, Germany) were selected for this study. Ten specimens for each group were prepared and polished. The surface roughness (Ra) and translucency (%) were measured by a 3D profilometer and spectrophotometer before and after the accelerated aging protocol (10,000 cycles, 5◦C, and 55◦C). The freeze-fracture surfaces of tested materials were observed by SEM. Results: Enamic HT had the lower surface roughness value of 82.56 ± 6.21 nm, while Ultimate HT owned the higher Ra of 125.89 ± 8.64 nm before thermal aging. Enamic HT had the lower transparency (%) of 55.02 ± 2.57, while Ultimate HT owned the higher transparency (%) of 58.89 ± 1.63 before thermal aging. Ra in tested CAD/CAM materials was greater than 0.2 μm after 10,000 thermocycles of 5/55◦C. Conclusions: The thermal aging led to a significant increase in surface roughness and a significant decrease in transparency in both CAD/CAM materials. Ultimate HT were significantly more translucent than Enamic HT before thermal aging, while Ultimate HT showed less translucent than Enamic HT after 10,000 thermocycles of 5/55◦C.

Epoxy resin (EP) can be flexibly bonded to various materials and has a wide range of applications in aerospace manufacturing. One of the most common applications is as a matrix phase in the preparation of advanced fiber composites. Therefore, it determines the mechanical properties of composites, particularly in view of the effect of differences in strength. To this end, we prepared tensile and compressive specimens of EP according to the ASTM standard and carried out quasi-static loading tests at different strain rates (0.001 to 0.1 s−1). The results show that EP has an obvious strain rate dependence, and the elastic modulus, yield strength, and plastic flow platform in tension and compression have obvious differences. Furthermore, by fitting the experimental stress-strain curves in tension, we used the power function to establish a theoretical model in terms of yield stress and elastic modulus. Subsequently, the nonlinear constitutive models in the compressive state were established based on the Sherwood-Frost model. Thus, a complete constitutive model was obtained which takes into account both tensile and compressive differences. Based on these constitutive models, the tensile and compressive mechanical behaviors obtained by parameter inversion are in good agreement with their experimental results, proving that the developed constitutive models have good theoretical prediction capability. These research results provide a reference for the practical engineering application of EP, especially for the fiber-reinforced EP composites.

Background: Neuroinflammation and oxidative stress are key features of Alzheimer’s disease (AD), offering potential targets for localized therapeutic intervention. Delivering neurotrophic factors specifically to inflamed brain regions could improve treatment efficacy while minimizing systemic exposure. Methods: We developed a reactive oxygen species (ROS)–responsive hydrogel incorporating oxidation-labile linkers to enable the on-demand release of brain-derived neurotrophic factor (BDNF). The hydrogel’s porous structure was characterized via Scanning Electron Microscopy (SEM), and drug release behavior was evaluated under oxidative and physiological conditions. Cytoprotective efficacy was tested in H2O2-treated PC12 cells. Results: The hydrogel exhibited high porosity and released BDNF rapidly in oxidative environments, with minimal release under normal conditions. It reduced intracellular ROS in stressed PC12 cells. Conclusion: This ROS-responsive hydrogel serves as a biocompatible and intelligent drug delivery system with potential for targeted oxidative stress modulation and neurotrophic support in the treatment of AD.

This paper was created within the EU Horizon project - RECICLARM - which conducted waste management research with the purpose of recycling up to 70% of Europe’s waste [1]. Our investigation focused on developing an algorithm capable of accurately classifying materials including plastic onces in categories of interest with the help of machine learning. Various types of materials and input variables have been documented and considered while prototyping and testing the intelligent classification algorithm, which resulted in a precise and efficient solution.

Treating skin injuries remains challenging due to issues like wound infections. In this study, polyvinylidene fluoride (PVDF)/polyethylene oxide (PEO)/azithromycin (AZ) composite nanofibers were prepared using electrospinning to reduce bacterial infections in skin wounds. The surface morphology, chemical structure, and hydrophilicity of the nanofibers were characterized using scanning electron microscopy, Fourier transform infrared spectroscopy, and contact angle measurements, respectively. Antibacterial performance tests revealed that increasing the AZ dosage expanded the antibacterial zone, indicating improved effectiveness. Furthermore, experiments on rat skin infections showed that the PVDF/PEO/AZ membrane inhibited suppuration at S. aureus-infected wound sites. These findings demonstrate the potential of AZ-loaded PVDF/PEO nanofiber membranes as effective antibacterial dressing.

Comparing and evaluating the fracture load of different posts and composite core of root canal-treated teeth is the aim of this study. Endodontically treated teeth were restored with zirconia (ZP), prefabricated glass fiber (GFP), and carbon (CP) post systems. Single root eighty maxillary 2nd premolars were chosen, and they received endodontic therapy. Depending on the kind of length used, the teeth were randomly assigned to four groups (n = 20), each of which was then divided into two subgroups: subgroup 1/2 removed the one-half sealing material, and subgroup 2/3 removed two-thirds of the sealing material. Prefabricated glass fiber posts were used in Group I, zirconia posts were used in Group II, carbon posts were used in Group III, and direct composite resin restoration without a post was used in Group IV (control). Samples were loaded into a universal testing machine, and statistical interpretations were made. Fracture resistance was noted. The results of the fracture one-way ANOVA were used to examine the load, and then multiple comparisons with the Bonferroni test with a threshold significant value (α=0.05). The prefabricated glass fiber post group, the carbon post, the zirconia post, and the control group all had lower fracture loads than the zirconia post.

Due to their high energy dissipation properties, in recent years, composite materials based on natural resins and fibers have been increasingly used. The paper studies the vibration behavior of composite bars reinforced with chopped wheat straw and, respectively, chopped sunflower seed shells. As matrix, an epoxy resin and, respectively, a hybrid resin based on rosin were used. A mathematical model useful for the study of damped vibrations is presented. For each of the analyzed bars, the frequency and damping factor for the first natural vibration mode are experimentally determined. Based on the experimental data, a coefficient that characterizes the vibration damping capacity for each bar is determined.

In this study, fan blades and thermosetting polyurethane foam were mechanically recycled, and glass fibers of different lengths and polyurethane powders of different particle sizes were separated by crushing and screening. The recycled materials with different particle sizes and mass fractions were selected and homogeneously mixed with the matrix thermoplastic polypropylene powder, and nine groups of different composite insulation boards were prepared using hot press molding method. The tensile strength, flexural strength and thermal conductivity of different insulation boards were analyzed. The results show that when the glass fiber mass fraction is 20%, the mechanical properties can reach the maximum value, and its tensile strength and bending strength are 7.196 MPa and 13.2 MPa, respectively. The thermal conductivity can reach the minimum value of 0.091 W/(m∙K) when the glass fiber mass fraction is 10%. In this study, polyurethane and glass fibers were recycled at the same time to obtain insulation boards with good mechanical strength and thermal insulation properties, which provides new possibilities for the development of insulation materials.

Perishable food products, including fruits, vegetables, and seafood, require preservation techniques to extend their shelf life. In recent years, nanotechnology has emerged as a promising approach to enhance the properties of edible coatings. Nanocomposite coatings incorporating various materials and technologies have been developed to optimize coating performance. PSA, SEM, XRD, and FT-IR analyses were conducted to characterize the physical and morphological properties of these nanocomposite coatings. The findings indicated that the use of Ultra-Turrax (UT) technology in the preparation of the coating solution resulted in smaller particle sizes (458.9-1037.2 nm), improved visual appearance, and smoother films with uniformly distributed nanoparticles on the surface. XRD and FT-IR analyses confirmed the crystallinity and functional groups of ZnO and TiO₂ within the nanocomposite coatings. These newly developed coatings have significant potential as environmentally friendly packaging materials and preservation technologies to extend the shelf life of perishable food products.

In order to solve the wall thickness error problem of filament-based extrusion additive manufacturing (MEAM) of thin-walled model and to improve the printing accuracy of MEAM thin-walled model. In this study, a square thin-walled model A was designed as the experimental specimen, and a wall thickness error correction method based on pre-experiment was proposed, by which the corrected extrusion flow rate R was calculated to be 92.8%. Model A was reprinted using the corrected extrusion flow rate (92.8%), and the wall thickness error of model A printed using the corrected extrusion flow rate was found to be significantly reduced by spiral micrometer measurement. When model A was observed through an industrial microscope, it can be seen from the sidewall surface detail diagram that the surface of model A printed with the corrected extrusion flow rate has no bumps, cracks and other structures, and the surface quality is better; moreover, it can be seen from the cross-sectional dimension diagram that the wall thickness (0.403 mm) of model A printed with the corrected extrusion flow rate (92.8%) is significantly reduced compared to the wall thickness (0.472 mm) of model A printed with the default extrusion flow rate (100%), and is close to the designed wall thickness (0.400 mm), which further verifies that the wall thickness error of the MEAM thin-walled model with the corrected extrusion flow rate has been significantly reduced.