Repositório IC-Online
Repositório Científico da Instituição
Entradas recentes
Alginate/Aloe Vera Hydrogel Films for Biomedical Applications
Publication . Pereira, Rúben F.; Mendes, Ausenda; Bártolo, Paulo
This paper describes a methodology to produce hydrogel films, composed of alginate and Aloe vera, for wound healing and drug delivery applications. The films were prepared through the solvent-casting method and subsequently submitted to an additional cross-linking step to improve their properties. Alginate films with different Aloe vera contents (5, 15 and 25%) were prepared and its properties evaluated in terms of thickness, transparency, swelling behavior and in vitro degradation. Results show a positive influence of Aloe vera on the transparency of the films, in both dry and wet state. Films were immersed in acetate buffer at pH 5.5 simulating the value of the skin, to evaluate its water absorption capacity. It was found that water absorption increases as the Aloe vera content increases, suggesting that Aloe vera enhances the hydrophilic properties of the films. The in vitro degradation tests were performed through the incubation of the films, for 10 weeks, in a simulated body fluid at 37°C. After this period, films kept its structure integrity exhibiting a weight loss in the range of 14.1-18.6%.
Morphological Characteristics of Electrospun PCL Meshes – The Influence of Solvent Type and Concentration
Publication . Dias, J.; Bártolo, P.
Fibrous scaffolds, with fiber dimensions on the nanometer scale, are ideal for tissue engineering applications as they can mimic the physical structure of natural extracellular matrix. This paper investigates the effect of the solvent type and the solvent concentration on the morphological and hydrophobic characteristics of Polycaprolactone (PCL) meshes. Acetone and acetic acid with triethylamine (TEA) were used as solvents with different concentrations of PCL. Results show that its use allows the formation of meshes with high surface roughness, less surface friction and less hydrophobicity.
Cranial Biomechanical Simulation
Publication . Perestrelo, Pedro; Bártolo, Paulo; Paranhos, Maurício; Noritomi, Pedro; Silva, Jorge
In order to improve the understanding, detection and prevention of traumatic brain injury (TBI), a step forward must be taken in the research. A pursue of biomechanical and clinical theories in separate, must give place to a joined effort. Therefore, it is proposed the development of a virtual platform using BioCAD protocol, surface modeling software and finite element method (FEM) analysis software, in order to achieve a model that can be adapted to the needs of the user or patient. This will result in an innovative and most needed tool, so that research and prevention of TBI enter a new level.
The influence of cadmium contamination and salinity on the survival, growth and phytoremediation capacity of the saltmarsh plant Salicornia ramosissima
Publication . Pedro, Carmen; Santos, Márcia S.S.; Ferreira, Susana; Gonçalves, Sílvia C.
The major aim of this study was to evaluate the capacity of Salicornia ramosissima on Cadmium phytoremediation under distinct salinities and, consequently, the toxic effects on the plant’s development. A greenhouse experiment was performed, using two Cd concentrations (50 and 100 mg l 1) in different salinities (0, 5 and 10). Mortality and weight variation, observed at the end of the experiment, showed significant differences between some treatments, meaning that these variables were affected by the salinity and Cd concentrations. The highest Cd accumulation was detected in the roots, and decreased with the increase of salinity and Cd concentration. S. ramosissima is a potential candidate for Cd phytoremediation at salinities close to 0 and its capabilities in Cd phytoaccumulation and phytoestabilization proved to be quite interesting. The optimization of phytoremediation processes by S. ramosissima could turn possible the use of this plant in the recovery of contaminated ecosystems.
Efficient depth error concealment for 3D video over error-prone channels
Publication . Marcelino, S.; Assunção, P.; Faria, Sérgio M. M. de; Soares, S.
This paper addresses the problem of multivew videoplus-depth (MVD) decoding with corrupted depth maps due to transmission errors. A method for spatial error concealment
of depth maps in MVD is proposed to efficiently recover lost blocks. The proposed method relies on the colour image and geometric curve fitting for accurate reconstruction of the lost contour segments in the corresponding depth map areas. Such reconstructed depth map contours are then used as boundaries at different depth planes to recover the missing depth values through weighted interpolation. The method performance is evaluated by the objective quality (PSNR) of the synthesised views. Images decoded with the reconstructed depth maps are compared with those of a reference method based on bidirectional interpolation. The proposed method exhibits PSNR gains up to 1.66dB higher than the reference one and better performance is consistently achieved for different visual content.