197 documents found, page 1 of 20
Tribological properties of antimicrobial surfaces for orthopaedics and oral reh...
Veloso, J.; Borges, J.; Vaz, F.; Carvalho, O.; Souza, J. C. M.; Gomes, J. R.Inflammatory reactions around implants and prosthetics can occur due to the accumulation of pathogenic bacteria species. The long-term success of implants and prostheses depends on the healthy state of surrounding mucosa, bone, and connective tissues, that can be controlled by manufacturing surfaces with specific physical-chemical aspects to prevent the accumulation of bacteria. Among several properties, the fr...
Titanium based dry electrodes for biostimulation and data acquisition
Conselheiro, Raul; Lopes, Claudia; Azevedo, Nelson; Leitao, Paulo; Agulhari, Cristiano; Veloso, H.; Vaz, F.; Gonçalves, João Lucas; Franco, TiagoWet electrodes rely on conductive electrolyte gel for proper perfor- mance, usually presenting high setup time and being disposable or requiring time-consuming cleaning methods. Skin irritation and signal quality deterioration are some of the problems that may occur with these electrodes. Therefore, to overcome these drawbacks, 3D printed bases using Fused Deposition Modelling (FDM) with Polylactic acid (PLA), ...
Optimization of Au:CuO thin films by plasma surface modification for high-resol...
Proença, Manuela; Rodrigues, Marco S.; Meira, Diana I.; Castro, M. Cidalia R.; Rodrigues, Pedro V.; Machado, A. V.; Alves, Eduardo; Barradas, Nuno P.In this study, thin films composed of gold nanoparticles embedded in a copper oxide matrix (Au:CuO), manifesting Localized Surface Plasmon Resonance (LSPR) behavior, were produced by reactive DC magnetron sputtering and post-deposition in-air annealing. The effect of low-power Ar plasma etching on the surface properties of the plasmonic thin films was studied, envisaging its optimization as gas sensors. Thus, t...
Chitosan micro-membranes with integrated gold nanoparticles as an LSPR-based se...
Meira, Diana Isabela Faria; Proença, Maria Manuela Carvalho; Rebelo, Rita Daniela Nogueira; Barbosa, Ana Isabel Ferreira; Rodrigues, Marco S.Currently, there is an increasing need to develop highly sensitive plasmonic sensors able to provide good biocompatibility, flexibility, and optical stability to detect low levels of analytes in biological media. In this study, gold nanoparticles (Au NPs) were dispersed into chitosan membranes by spin coating. It has been demonstrated that these membranes are particularly stable and can be successfully employed...
High frequency dielectric characterization of graphene doped flexible ceramics ...
França Junior, S. A. N.; Souza, A. L. R.; Cruz, L. B.; Vaz, F.; Ferreira, Armando José Barros; Bohn, F.; Acchar, W.; Correa, M. A.This paper explores the tape casting technique to produce flexible heterostructured multilayers composed of graphene nanoplatelets doped Alumina and Ceria doped Nickel Oxide-Gadolinium. Given the excellent mechanical and electrical properties of graphene, multilayers were structured to explore the dielectric properties at a high-frequency regime. The stability of the suspensions, measured by rheological charact...
Assessing the relaxation mechanisms contributions on magnetoimpedance effect in...
Santos, J. G. S.; Silva, E. F.; Gamino, M.; Ferreira, Armando José Barros; Vaz, F.; Bohn, F.; Correa, M. A.Damping parameter plays a key role in the magnetization dynamics of ferri/ferromagnetic materials with potential technological applications. Experimentally the damping parameter can be estimated from the linewidth of the ferromagnetic resonance experiment, which is altered by distinct mechanisms associated with extrinsic contributions, such as spin pumping and two-magnon scattering mechanisms. Here we perform a...
Plasmonic strain sensors based on Au-TiO2 thin films on flexible substrates
Rodrigues, Marco S.; Borges, Joel; Vaz, F.This study aimed at introducing thin films exhibiting the localized surface plasmon resonance (LSPR) phenomenon with a reversible optical response to repeated uniaxial strain. The sensing platform was prepared by growing gold (Au) nanoparticles throughout a titanium dioxide dielectric matrix. The thin films were deposited on transparent polymeric substrates, using reactive magnetron sputtering, followed by a lo...
Unraveling the role of magnetic anisotropy on the thermoelectric response: A th...
Correa, M. A.; Gamino, M.; De Melo, A. S.; Lopes, M. V. P.; Santos, J. G. S.; Souza, A. L. R.; França Junior, S. A. N.; Ferreira, A.Magnetic anisotropies have a key role in tailoring magnetic behavior in ferromagnetic (FM) systems for specific sensor applications. Furthermore, they are also essential elements for manipulating the thermoelectric response in anomalous Nernst effect (ANE) and longitudinal spin Seebeck effect (LSSE) systems at unsaturated field regimes. Here, we propose a theoretical approach and explore the role of magnetic an...
Immobilization of streptavidin on a plasmonic Au-TiO2 thin film towards an LSPR...
Pereira-Silva, Patrícia; Meira, Diana I.; Costa-Barbosa, Augusto; Costa, Diogo; Rodrigues, Marco S.; Borges, Joel; Machado, Ana V.; Cavaleiro, AlbanoOptical biosensors based on localized surface plasmon resonance (LSPR) are the future of label-free detection methods. This work reports the development of plasmonic thin films, containing Au nanoparticles dispersed in a TiO<sub>2</sub> matrix, as platforms for LSPR biosensors. Post-deposition treatments were employed, namely annealing at 400 °C, to develop an LSPR band, and Ar plasma, to improve the sensitivit...
Flexible multifunctional hard coatings based on chromium oxynitride for pressur...
Ferreira, Armando José Barros; Correa, Marcio A.; Lanceros-Méndez, S.; Vaz, F.The present work reports on the development of piezoresistive chromium oxynitride (CrN1−O) thin films deposited on flexible polymeric substrates. The relationship between the reactive gas supply (composed of 15% O2 and 85% N2) and the electromechanical response was analyzed in CrN1−O thin films, produced by glancing angle deposition (GLAD) in a sputtering DC-reactive environment. GLAD was used to modify the nor...