It is crucial for clinical needs to develop novel titanium alloys feasible for long-term use as orthopedic and dental prostheses to prevent adverse implications and further expensive procedures. The primary purpose of this research was to investigate the corrosion and tribocorrosion behavior in the phosphate buffered saline (PBS) of two recently developed titanium alloys, Ti–15Zr and Ti–15Zr–5Mo (wt.%) and compare them with the commercially pure titanium grade 4 (CP–Ti G4). Density, XRF, XRD, OM, SEM, and Vickers microhardness analyses were conducted to give details about the phase composition and the mechanical properties. Additionally, electrochemical impedance spectroscopy was used to supplement the corrosion studies, while confocal microscopy and SEM imaging of the wear track were used to evaluate the tribocorrosion mechanisms. As a result, the Ti–15Zr (α + α′ phase) and Ti–15Zr–5Mo (α″ + β phase) samples exhibited advantageous properties compared to CP–Ti G4 in the electrochemical and tribocorrosion tests. Moreover, a better recovery capacity of the passive oxide layer was observed in the studied alloys. These results open new horizons for biomedical applications of Ti–Zr–Mo alloys, such as dental and orthopedical prostheses.
Titanium (Ti) and its alloys are widely used in biomedical applications due to their excellent mechanical properties and biocompatibility. However, they are a concern due to the possibility of cytotoxic effects coming from the degradation products. This degradation occurs by the combined action of corrosion and mechanical wear of these materials, which are released in the biological environment by the biomaterial implanted. The present article aims to investigate a new route to improve electrochemical and tribological performance with surface modification. Regarding the deposition of a protective layer on the surface, it consists of titanium oxide (TiO2) and calcium phosphate (CaP). Both coatings were performed by chronoamperometric methods with titanium oxidation at 1 V and calcium phosphate reduction at −1.5 V. The corrosion and tribocorrosion tests demonstrated the effective combination of TiO2 and CaP layer to protect the Ti substrate. Furthermore, this coating combination reduced corrosion degradation and mechanical wear in PBS, simulating a physiological environment. Additionally, it was observed that this combination of coating decreased the dissipated energy, and consequently, the wear decreased during sliding tests. All these findings indicate the protective behavior of the TiO2 and CaP layer during the tribocorrosion tests.
Aim: To established a simple, controlled and reproducible method to synthesize gallium (Ga)-coated polydopamine (PDA) nanoparticles (NPs). Materials & methods: PDA NPs were synthesized in alkali medium with posterior Ga shell formation due to ion chelation on the NP surface. Results: The obtained results with energy-dispersive x-ray spectroscopy confirmed the incorporation of Ga on the PDA NP surface. The cytotoxicity of Ga-coated PDA NPs was evaluated in vitro at different concentrations in contact with human adipose-derived stem cells. Further cell analysis also demonstrated the benefit of Ga-coated PDA NPs, which increased the cell proliferation rate compared with noncoated PDA NPs. Conclusion: This study indicated that Ga could work as an appropriate shell for PDA NPs, inducing cell proliferation at the analyzed concentrations.
Cenário de UsoO autismo é um distúrbio do desenvolvimento que se caracteriza por alterações presentes desde idade muito precoce, com impacto múltiplo e variável em áreas nobres do desenvolvimento humano como comunicação, interação social, aprendizado e capacidade de adaptação (SCHWARTZMAN, 2011).No que diz respeito a comunicação, o indivíduo com autismo possui dificuldade em utilizar todos os aspectos da linguagem verbal ou não-verbal, incluindo gestos, expressões faciais, linguagem corporal, ritmo e modulação na linguagem verbal. Em relação a socialização, evidencia-se a dificuldade de relacionar-se com os outros, mostrando incapacidade de compartilhar sentimentos, gostos e emoções. Por sua vez, a dificuldade com o uso da imaginação se caracteriza por rigidez e inflexibilidade nas várias áreas do pensamento, linguagem e comportamento da criança, percebida por uma forma de brincar desprovida de criatividade e pela exploração peculiar de objetos e brinquedos (MELO, 2007).Todas estas dificuldades comprometem a aprendizagem de crianças com autismo, tornando o ensino uma tarefa desafiadora. Apesar dos comprometimentos cognitivos que o autismo acarreta, acredita-se que o ensino é possível utilizando recursos e métodos adequados, em programas individualizados, elaborados de acordo com as necessidades específicas do aluno (FERNANDES, 2010). Muitas abordagens têm sido elaboradas com este propósito trabalhando carências específicas no autista. Apesar da limitação existente em muitos modelos resultados animadores tem sido registrados.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.