Objective The aim of this study to evaluate the effects of autologous conditioned serum (ACS) on the healing of transected rat Achilles tendons via the assessment of biomechanical and histological parameters. Methods The study was conducted on 45 male Sprague–Dawley rats. Five rats were used as donors for ACS preparation. Animals were randomly assigned to the experimental or control group. In both groups, the Achilles tendon was cut transversally and then sutured. In the placebo control and ACS-treated groups, saline or ACS, respectively, was injected into the repair zone three times after surgery. Ten rats from each group (ACS group, n = 20; control group, n = 20) were euthanized at days 15 and 30 after surgery for histopathological (n = 5) and biomechanical (n = 5) testing. The histopathological findings were interpreted using the Bonar and Movin scales. Tendon remodelling was evaluated via the immunohistochemical staining of collagen type 3. Biomechanical effects were assessed by tensile testing. Results The Bonar and Movin scale scores were significantly better in the ACS-treated group on both day 15 (p = 0.003 and p = 0.003, respectively) and day 30 (p = 0.005 and p = 0.004, respectively). The immunohistochemical density of collagen type 3 was significantly lower in the ACS-treated group on day 30 (p = 0.018). The type 1/3 collagen ratios of the groups were similar on days 15 and 30, as determined by Sirius Red staining (p = 0.910 and p = 0.133, respectively). In the biomechanical assessment results, the ACS-treated group's maximum load to failure values were significantly higher on day 15 (p = 0.049). Conclusion Injection of ACS had a positive effect on the histopathological healing of rat Achilles tendons on days 15 and 30 and on biomechanical healing on day 15. ACS treatment contributed to lowering the collagen type 3 density by day 30. According to our study, ACS may be favourable for the treatment of human Achilles tendon injuries and tendinopathies. ER -

Acrylonitrile-butadiene-styrene test specimens were additively manufactured by fused deposition method to investigate the effects of infill pattern and density on wear rate, coefficient of friction, wear mechanisms, and microscopic wear characterization. The surface morphology of specimens was characterized using a scanning electron microscope. Under constant parameters of applied load, sliding speed, and sliding time, wear tests were carried out at room temperature. The study revealed that a grid pattern of high infill density and a honeycomb pattern of low infill density showed the lowest wear rate and lowest coefficient of friction compared to the rectilinear pattern. Infill pattern and density affected the wear rate behavior of specimens directly. Moreover, adhesion between additively manufactured layers along with surface texture affects the wear behavior and wear rate. Increasing infill density allowed poor cooling of previously built layers. Longer process time results in rough surfaces.

Purpose: This study evaluates the effects of a novel nanohydroxyapatite gel and Er: YAG laser on the surface roughness, surface morphology, and elemental content after dentin hypersensitivity treatments. Methods: Dentin discs (2 × 3 × 3 mm³) were prepared from 75 human molars. Out of 75 human molars, 50 were used to evaluate surface roughness and randomly divided into five groups: Group ID (intact dentin), Group DD (demineralized dentin), Group BF (fluoride varnish/Bifluorid 10), Group Lsr (Er: YAG laser-50 mJ, 0.50 W, 10 Hz), and Group NHA (nanohydroxyapatite-containing gel). Dentin hypersensitivity was stimulated by 35% phosphoric acid for 1 min (except Group ID). The surface roughness (Ra, μm) was measured via contact profilometry (n = 10). Out of the 75 sound human molars, 25 were used to evaluate the surface morphology and elemental content using scanning electron microscopy and energy-dispersive X-ray spectroscopy (n = 5). The data were statistically analyzed using Welsch ANOVA, Games–Howell, Kruskal–Wallis, and Dunn tests (p < 0.05). Results: Group Lsr showed significantly lower surface roughness than Group NHA and Group BF (p < 0.05). The SEM analysis indicated that most of the dentinal tubules were obliterated for Group NHA. Precipitant plugs with partially occluded dentinal tubules were observed for Group BF, while partially or completely occluded tubules with a melting appearance were detected for Group Lsr. The EDS analysis revealed that Group NHA and Group Lsr presented similar calcium and phosphorus amounts to Group ID. All dentin hypersensitivity treatment methods could provide promising results in terms of tubular occlusion efficiency. However, laser treatment resulted in smoother surfaces, which could help prevent dental plaque accumulation.

Carbon nanotube (CNT) reinforced 6063 aluminum (Al) matrix composites were fabricated by vacuum-assisted infiltration of molten 6063 Al alloy into a CNT preform to enhance compressive mechanical properties. Preforms were produced with different amounts of chemically functionalized CNTs to obtain three different CNT reinforcement ratios (0.25, 0.50, and 0.75 wt.%). In addition to the investigation of properties throughout all stages of the preparation of the CNTs, CNT preforms and fabricated composites by various methods of analysis, all steps of the composite fabrication process, as well as the compressive mechanical test results of CNT/6063 Al composites are all discussed. Approximately 250% and 280% increases in the yield and ultimate compressive strength, respectively, are achieved with low-purity CNT addition. Consequently, it is confirmed from the micrographs that the mechanical enhancements of the composites are mainly interrelated with the successful bridging of CNTs in the matrix material. Meanwhile, it is observed that both the modified Halpin-Tsai model and the modified Halpin-Tsai model developed with a dispersion-based prediction model results match with experimental results. Overall results can be accepted as developmental stages of significant progress in the CNT preform reinforced metal matrix composites field.

The purpose of this investigation is to determine the impact of titanium dioxide nanotubes (TiO₂-n) on the mechanical and antibacterial properties of bulk-fill composite resin. TiO₂-n were synthesized in laboratory conditions using the hydrothermal method. Varying amounts of TiO₂-n were included in the bulk-fill composite resin. Microhardness, surface roughness, and the three-point bending test were used to determine the mechanical properties of the composite. After the flexural strength test, the fractured surfaces of the composite resin were examined with a high-resolution scanning electron microscope. The antibacterial activity of Streptococcus mutans (S.mutans) and Lactobacillus Casei (L.casei) was assessed using a direct contact test. The statistical examination was completed using IBM SPSS Statistics 22. Group differences were compared using the Kruskal Wallis and Dunn tests (p < 0.05). The addition of TiO₂-n did not change the roughness of the bulk-fill composites (p > 0.05). Adding 0.5% and 1% TiO₂-n increased the microhardness of the bulk-fill composite (p < 0.05). Adding TiO₂-n did not change the three-point bending results of the bulk-fill composite (p > 0.05). Though adding TiO₂-n did not have an antibacterial impact on S.mutans (p > 0.05), adding 0.5% TiO₂-n produced an antibacterial impact on L.casei in daylight (p < 0.05). The addition of 0.5% and 1% TiO₂-n increased the microhardness of the top surface of the bulk-fill composite without negatively affecting surface roughness or the composite’s three-point bending properties Adding 0.5% TiO₂-n to the composite resin produced an antibacterial impact on L.casei in daylight.