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The influence of two different spark plasma sintering (SPS)-based processing routes (i.e., reactive SPS [RSPS] and nonreactive SPS) on the properties of TaB2-TaC composites was investigated. Ta2O5 and B4C powders were used as starting materials in the RSPS method, and synthesis and densification of TaB2-TaC composites were accomplished in a facile single step. The effect of sintering temperature and time on the microstructure and densification of the in-situ RSPS were investigated. The obtained results were compared with nonreactive spark plasma sintered TaB2-TaC composites. The highest densification (~99.5%) was achieved for the TaB2-TaC composite with 6.64 vol.% TaC after reactive sintering at 1550° C under 40 MPa with a 5 min holding time. Although lower SPS temperature was used in the RSPS method, better densification and higher Vickers hardness were obtained compared to the nonreactive SPS. While platelet-shaped TaC formation was observed in both processes, the average grain size was smaller in the RSPS method. On the other hand, no significant difference was detected in the oxidation behavior of the composites produced by RSPS and nonreactive SPS. [ABSTRACT FROM AUTHOR]

The current research focuses on the findings of an investigation on optimizing of an electrospun antibacterial gelatin nanocomposite membrane for bone tissue engineering applications. For this reason, soluble starch coated silver nanoparticles (Ag‐NPs) and bioactive glass particles (BG) were incorporated in to gelatin (Gt) to fabricate Gt/Ag‐NPs/BG nanocomposite membranes. Employing Box‐Behnken design, second‐order models have been successfully obtained to evaluate the statistical significance of individual and interaction effects of applied voltage, tip‐to‐collector distance (TCD), and flow rate on fiber diameter. There was a reasonable agreement between the regression R2 value (0.9542), R2 predicted value (0.8768), and the R2 adjusted value (0.9286) across the entire factor space with identical observations for the experimental and model values. Under optimum conditions (applied voltage of 26 kV, TCD of 180 mm, and flow rate of 0.5 mL/h), the nanocomposite membrane with similar fiber size of bone tissue extracellular matrix can be fabricated with the predicted value of 557 nm obtained by the proposed model. The optimized nanofiber membrane was fabricated under these conditions and average fiber diameter of this membrane was found as 472 ± 94 nm. The characterization studies of this nanofiber suggest that obtained nanocomposite is a potential candidate for bone tissue engineering applications. [ABSTRACT FROM AUTHOR]

The aim of this study was to prepare and to characterize the structure of Al2 O3-3 YSZ composites with 5% Ti O2 addition as well as the surface modification upon treatments with Sn F2 and Na BF4, respectively. SEM micrographs showed the controlled densification of the composites as an effect of 3 YSZ and Ti O2 addition to alumina matrix. By FTIR and XRD, the characteristics of Al- O and Zr- O vibrations, respectively, the diffractions lines related to α-corundum and zirconia in tetragonal phase were discussed. Qualitative and quantitative results obtained by XPS and ATR FTIR demonstrated that the proposed materials are more sensitive to Sn F2 than to Na BF4 treatment. [ABSTRACT FROM AUTHOR]

Purpose: The aim of this studywas to investigate the polymerization efficiency of dualcured resin cement beneath different shades of zirconia-based feldsphathic ceramic restorations. Materials and Methods: Five translucent zirconia (Zirkonzahn) discs (4.0-mm diameter, 1.2-mm height) were prepared. Feldsphathic ceramic (1.2 mm) (Noritake Cerabien Zr) in 5 shades (1M2, 2M2, 3M2, 4M2, 5M2)was applied on the zirconia discs. Twelve dual-cure resin cement specimens were prepared for each shade, using Panavia F 2.0 (Kuraray) in Teflon molds (4.0-mm diameter, 6.0-mm height), following the manufacturer's instructions. Light activation was performed through the zirconia-based ceramic discs for 20 seconds, using a quartz tungsten halogen curing device (Hilux 200) with irradiance of 600 mW/cm². Immediately following light curing, specimens were stored for 24 hours in dry, light-proof containers. Vickers hardness measurements were conducted using a microhardness tester with a 50-g load applied for 15 seconds. The indentations were made in the cross sectional area at four depths, and the mean values were recorded as Vickers hardness number (VHN). Results were statistically analyzed with one-way ANOVA and Tukey HSD test (p < 0.05). Results: A statistically significant decrease in VHN of the resin cement was noted with increasing depth and darkness of the shade (p < 0.05). Conclusion: Curing efficiency of dual-cure resin cement is mainly influenced by the lightness of the shades selected. [ABSTRACT FROM AUTHOR]