Search

Abstract: The chemical and mechanical stabilities of colored interference thin films on stainless steel were investigated by thermally aging these films at 150 °C for different aging times of 2, 4, 8, 16 and 256 h. The thermally aged films were morphologically characterized using field emission scanning electron microscopy (FESEM) and atomic force microscopy (AFM), and exhibited decreased porosity after thermal treatment. Fourier transform infrared spectroscopic (FTIR) analyses and depth sensing indentation tests confirmed that the sample aged for 2 h had better mechanical characteristics than samples that had not been thermally aged. Further, thermally aged samples exhibited increased hardness and abrasion wear resistance. [Copyright &y& Elsevier]

Abstract: The Oliver–Pharr method was used to calculate the elastic modulus from the reloading curve and was compared to the traditional unloading curve method. Nanoindentation and microindentation testing instruments were used. This method was applied to load–unload–reload–unload, multistep, and cycle indentation testing procedures at various hold times and force rates. On unloading the reverse plasticity added to the elastic recovery which increased the apparent elastic modulus. During reloading there was mainly elastic deformation making it more reliable for the elastic modulus calculation. It was also found that the metals tested started yielding between 70% and 100% of the reload curve. The reload indentation elastic modulus for fused silica and several metals was equivalent to the tensile test elastic modulus from reference literature. [Copyright &y& Elsevier]

Combination-based chemotherapies have been the standard treatment for multiple solid tumors since the 1960s. Combined therapies where both agents have toxicity results in dose-limiting effects. α- tocopherol succinate (TS) is an analogue of vitamin E that exhibits antitumor properties in the absence of toxicity. Hence, its combination with a frontline chemotherapy, doxorubicin (DOX) is an alternative to increase antitumor efficacy. Therefore, the aim of this work was to evaluate the antitumor activity of nanostructed lipid carriers (NLC) loaded with TS and DOX. The NLC-TS-DOX were prepared, characterized and radiolabeled with technetium-99m. Cytotoxicity studies were performed in vitro , using two breast cancer cell lines, MDA-MB-231 and 4T1. Biodistribution and antitumor activity were evaluated in 4T1 tumor-bearing mice. The results showed that NLC-TS-DOX had a small diameter (85 nm) and a long blood clearance (T 1/2 β = 1107.71 min) that consequently resulted in a higher tumor uptake compared to contralateral muscle for up to 48 h. Drug combination studies in MDA-MB-231 and 4T1 cells showed a combination index below 0.8 at ED 50-90 for both cell lines. Interestingly, a high synergism was found at ED 90. Antitumor activity showed a better control of tumor growth for animals treated with NLC-ST-DOX. The small particle size, along with the EPR effect and the controlled release of DOX from the particle, associated with the synergic combination between TS and DOX led to an increase of the antitumor efficacy. Therefore, NLC-TS-DOX can be considered a plausible alternative to improve antitumor efficacy in DOX therapeutic regimens. [ABSTRACT FROM AUTHOR]