Evaluation of properties of concrete coating composites based on polyurethane and reinforcing fibers.

The objective of this study is to evaluate the effect of Fiber-Reinforced Polymer (FRP) coatings on the mechanical properties of concrete structures, especially those used in the production of power distribution poles. These coatings consist of carbon, glass, hybrid, and aramid fibers embedded within a polyurethane matrix. Aramid fabrics from discarded ballistic garments were used to produce FRP. To achieve this, flexural, Charpy impact, and adhesion tests were conducted on the FRP-reinforced concrete. Additionally, Scanning Electron Microscopy (SEM) analyses were performed on the fracture regions of materials tested for impact resistance. The results indicated that all fabrics utilized in the study enhanced the mechanical properties of the concrete specimens in terms of flexural strength and toughness. The observed differences between the fiber types can be attributed to the unique chemical structures of each fiber and their respective interactions with the PU matrix at the interface. These findings suggest that such coatings can significantly improve the mechanical performance of concrete structures.

Efficacy of methotrexate-loaded poly(ε-caprolactone) implants in Ehrlich solid tumor-bearing mice.

CONTEXT: Methotrexate (MTX) is used in the treatment of malignancies; however, its clinical application is limited by its toxic dose-related side effects. An alternative to overcome the toxicity of the MTX in healthy tissues is the design of an implantable device capable of controlling the delivery of this drug for an extended period within the tumor site. OBJECTIVE: To develop methotrexate-loaded poly(ε-caprolactone) implants (MTX PCL implants) and to demonstrate their efficacy as local drug delivery systems capable of inhibiting Ehrlich solid tumor bearing mice. MATERIALS AND METHODS: MTX PCL implants were produced by the melt-molding technique and were characterized by FTIR, WAXS, DSC and SEM. The in vitro and in vivo release of MTX from the PCL implants was also evaluated. The efficacy of implants in inhibiting tumor cells in culture and the solid tumor in a murine model was revealed. RESULTS AND DISCUSSION: The chemical and morphological integrity of the drug was preserved into the polymeric matrix. The in vitro and in vivo release processes of the MTX from the PCL implants were modulated by diffusion. MTX diffused from the implants revealed an antiproliferative effect on tumor cells. Finally, MTX controlled and sustained released from the polymeric implants efficiently reduced 42.7% of the solid tumor in mice paw. CONCLUSION: These implantable devices represented a contribution to improve the efficacy and safety of chemotherapy treatments, promoting long-term local drug accumulation in the targeted site.