The electrochemical behaviour of two commercial titanium alloys Ti-6Al-4 V (ASTM F136) and Ti-13Nb-13Zr (ASTM F1713) was investigated in Ringer physiological solution at two pH values (5.5 and 7.0). The corrosion properties were examined by using electrochemical techniques: Potentiodynamic anodic polarization, cyclic polarization and electrochemical impedance spectroscopy (EIS). The electrochemical corrosion properties of both alloys at different conditions were measured in terms of corrosion potential (E (corr)), corrosion current density (i (corr)) and passivation current density (i (pass)). Equivalent electrical circuits were used to modulate EIS data, in order to characterize alloys surface and better understanding the pH effect on the interface alloy/solution.

No abstract

No abstract

No abstract

No abstract

Inicialmente agradeço a Deus e a todos da minha família que me ensinaram como viver e estar na vida.À professora Cecília Zavaglia pela confiança no meu trabalho e suporte na execução desse projeto.À Vanessa Bavaresco, que mais que coorientadora se mostrou uma grande amiga e esteve presente em todo tempo.Ao Carmo Pelliciari pelo incentivo e ajuda em todos os momentos.Ao professor José Gomes que me recebeu em seu grupo de pesquisa em Portugal e me orientou nos testes tribológicos. Professor Gomes muito obrigada pela oportunidade, minha estadia em Guimarães foi importante não só profissionalmente, mas também pessoalmente. Muito obrigada pela paciência e pela receptividade.Ao Sérgio Carvalho e Cristiano Abreu pela confiança e pelo profissionalismo com que me receberam em Guimarães e também minhas companheiras de trabalho Zinaida Doni e Dida Constantin.A todos os profissionais do talho Madre de Deus II, que gentilmente me cederam as amostras de cartilagem articular bovina.

Microneedle (MN) devices comprise of micron-sized structures that circumvent biological barriers in a minimally invasive manner. MN research continues to grow and evolve; the technology was recently identified as one of the top ten overall emerging technologies of 2020. There is a growing interest in using such devices in cosmetology and dermatological conditions where the MNs mechanically disrupt the outer skin barrier layer, creating transient pathways that allow the passage of materials to underlying skin layers. This review aims to appraise the application of microneedle technologies in skin science, provide information on potential clinical benefits, as well as indicate possible dermatological conditions that can benefit from this technology, including autoimmune-mediated inflammatory skin diseases, skin aging, hyperpigmentation, and skin tumors. A literature review was carried out to select studies that evaluated the use of microneedles as drug delivery enhancement for dermatologic purposes. MN patches create temporary pathways that allow the passage of material to deeper layers of the skin. Given their demonstrable promise in therapeutic applications, it will be essential for healthcare professionals to engage with these new delivery systems.

Poly(vinyl alcohol) (PVA) is a biomaterial that has interesting features for applications in soft tissue replacement due to its similarities in the mechanical properties of such tissues. This paper describes the preparation and characterization of PVA fibers obtained by electrospinning and crosslinked with potassium persulfate as thermoinitiator. These PVA fibers were characterized by Scanning Electron Microscopy (SEM) and Optical Microscopy (OM) to analyze the morphology of the spun samples. Finally, Fourier Transform Infrared Spectroscopy (FTIR) and differential scanning calorimetry (DSC) were performed and the results showed that the biomaterial was partially cross-linked, which indicates a potential use for dermal regeneration applications. The morphology of the fibers indicated that structural changes occurred in the biomaterial after thermal crosslinking.