CDRsp - Comunicações em conferências internacionais
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Percorrer CDRsp - Comunicações em conferências internacionais por Objetivos de Desenvolvimento Sustentável (ODS) "12:Produção e Consumo Sustentáveis"
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- Adhesion, proliferation and distribution of human mesenchymal stem/stromal cells (MSCs) in Poly(ɛ -caprolactone) (PCL) scaffolds with different pore sizesPublication . Moura, C. S.; Biscaia, S.; Viana, T.; Bártolo, P. J.; Silva, C. L. da; Cabral, J. S.; Ferreira, F. C.Tissue engineering, combining the use of biomaterials, mesenchymal stem/stromal cells (MSCs) and optimized culture medium formulations, is a very promising research field for tissue regeneration. This work is focused on the application of Poly(ε-caprolactone) scaffolds designed to have a spacing gradient between orthogonal fibres with diameters of 0.3mm with pore sizes ranging from 190 to 390 μm. Human bone marrow (BM)-derived MSCs, were used to evaluate cell adhesion, proliferation and distribution within the scaffolds. Specifically, we hypothesized if seeding MSC in scaffold regions with different pore sizes would influence cell proliferation. Therefore, MSC were seeded at the centre of scaffolds with either larger (390 μm) or smaller pores (190 μm). Results obtained showed similar levels of adhesion and proliferation in both configurations, with fold increase in total cell number of 5 after 13 days of cultivation; which indicates that no limitation for cell proliferation within the range of pore sizes studied is observed.
- Alginate/Aloe Vera Hydrogel Films for Biomedical ApplicationsPublication . Pereira, Rúben F.; Mendes, Ausenda; Bártolo, PauloThis 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%.
- Ask not what additive manufacturing can do for youPublication . Gibson, I.The paraphrase of John F Kennedy’s famous words is for 2 purposes. Firstly it is to acknowledge that there are some people who have considered that it is a major part of their life’s work to promote Additive Manufacturing (AM) technology as primarily a selfless act. AM comprises an outstanding range of technology that should be brought to public attention as a true revolution in how we design and manufacture products. The second purpose is to show that technology development is only one part of this promotion process and that there are other ways in which we can get involved. This paper describes the author’s journey over the (approximately) 20 years since he was introduced to what was then called Rapid Prototyping (RP). It is not a catalogue of research and development projects but rather a list of activities that he has been involved in to help promote and support AM technology over these years. It will describe the conferences, activities, associations and publications that have been created to allow academics and professionals to describe and discuss their work amongst themselves and to the larger society.
- Assessment of existing rc precast industrial buildings according with eurocode 8 - part 3Publication . Batalha, Nádia; Rodrigues, Hugo; Sousa, Romain; Varum, Humberto; Fernandes, PauloPrecast reinforced concrete (PRC) buildings are common in the Portuguese industrial park, as well as throughout Europe. In past earthquakes, namely in Italy and Turkey, this typology of buildings showed a poor performance, namely at structural level. One of the major concerns at structural level regards the connection between the beams and columns. In recent surveys at the Portuguese industrial buildings, it was observed that the buildings built before 1980 present, most of the times, only friction connections between beam and columns. This type of connection is pointed as one of the weakest structural system in this typology of structures and consequently led to serious local and global damage when subjected to seismic loads. Regarding this issue, it was considered appropriate and necessary the study of existing Portuguese buildings with this type of beam-to-column connection and compare it with the use of mechanical connections (dowels), which is a more common solution in the recent buildings. The seismic behaviour of two PRC buildings built with these two solutions was analysed considering nonlinear static and dynamic analyses addressing both global and local (connections) response parameters. When analysed in view of the seismic regulation for existing buildings (Eurocode 8 –Part 3), the results obtained show that, overall, this typology of buildings present an acceptable structural performance. Nonetheless, unsatisfactory performance was observed at the beam-to-column connection in one of the buildings built without steel dowels. The results presented in this study highlight the need to consider adequate models to simulate these connections in order to accurately represent the seismic behaviour on the structure and identify possible limitations in the use of nonlinear static procedures to assess the seismic performance of this typology of buildings. In general, the buildings in study, located in a region of moderate seismicity, exhibited a satisfactory behaviour. However particular attention should be paid to beam-to-column connections, especially in the case of friction connections. In this regard it is important to accurately represent in the model the mechanisms involved in the connections, particularly in buildings located in moderate to high seismic zones.
- BioFab toolbox – Software tools for biofabricationPublication . Alves, N.; Bártolo, P.; Ferreira, N.; Gaspar, M.; Mateus, A.This is a progress report of a project called BioFab Toolbox, funded by the Portuguese National Science Foundation, consisting of the development of a collection of software tools to assist in the process of rapid prototyping and rapid manufacturing of new products. This project is especially designed to produce scaffolds, grafts, implants and other medical applications usually designated as biofabrication (biofab).
- Characterisation of PCL and PCL/PLA Scaffolds for Tissue EngineeringPublication . Patrício, T.; Domingos, M.; A. Gloria; Bártolo, P.This paper investigates the use of PCL and PCL/PLA scaffolds produced using a novel additive biomanufacturing system called BioCell Printing. PCL/PLA blends were prepared using melt blend and solvent casting techniques. Scaffolds with 0/90° architecture and 350 μm of pore size were morphologically evaluated using scanning electron microscopy and atomic force microscopy. Biological tests, using osteosarcoma cell line G-63, were performed using the Alamar Blue Assay and Alkaline Phosphatase Activity. Results show that the BioCell Printing system produces scaffolds with regular and reproducible architecture, presenting no toxicity and enhancing cell attachment and proliferation. It was also possible to observe that the addition of PLA to PCL scaffolds strongly improves the biomechanical performance of the constructs.
- Comparison by computer fluid dynamics of the drag force acting upon two helmets for wheelchair racersPublication . Forte, P; Marinho, D. A.; Morouço, P; Pascoal-Faria, P.; Barbosa, T. M.The aim of this study was to compare the drag force created by two helmets (time trial and road)used by a wheelchair racer. The head and helmet of the racer were scanned to obtain the3D models. Numerical simulation was run on Fluent, having as output the drag force for both helmets (road and time trial) in two different positions (0º and 90º) and increasing velocities (from 2.0 to 6.5 m/s). The greatest aerodynamic drag was noted wearing a time trial helmet in 90º ranging from 0.1025N to 0.8475N; this was also the position with the highest drag. The velocity with higher drag for booth helmets was at 6.5 m/s. The time trial helmet at 0º had the lower aerodynamic drag, compared with the same position of road helmet. The drag force seems to be lower wearing the time trial helmet and keeping the 0º position and, thus, should be considered for sprinting events.
- Computational technologies in tissue engineeringPublication . Almeida, H. A.; Bártolo, P. J.In last decades, many advances have been made in order to aid the medical community. Numerous computational technologies have been developed and improved the efficiency in diagnostic and treatment of many diseases. Many of the technologies were developed with the main goal of aiding in the research of genetic and viral diseases. Tissue engineering is a multidisciplinary field that requires the combined effort of cell biologists, engineers, material scientists, mathematicians, geneticists, and clinicians toward the development of biological substitutes that restore, maintain, or improve tissue function. The success of this emerging medical domain relies on the current technological advances. This paper presents an overview of the existing computational technologies that have been implemented in tissue engineering and the design of scaffolds for tissue engineering applications. These computational technologies contemplate medical imaging processing, numerical calculations (structural, vascular and topological) and biofabrication techniques necessary for the scaffolds optimum design and production.
- Cranial Biomechanical SimulationPublication . Perestrelo, Pedro; Bártolo, Paulo; Paranhos, Maurício; Noritomi, Pedro; Silva, JorgeIn 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.
- Cyclic plastic behaviour of 7075 aluminium alloyPublication . Nogueira, F.; Cunha, J.; Mateus, A.; Malça, C.; Costa, J. D.; Branco, R.This paper aims at studying the cyclic plastic behaviour of the 7075-T651 aluminium alloy under fully-reversed strain-controlled conditions. Tests are conducted under strain-control mode, at room temperature, in a conventional servo-hydraulic machine, from smooth samples, using the single step method, with strain amplitudes (∆ε/2) in the range ±0.5 to ±2.75%. This material has exhibited a mixed behaviour, i.e. cyclic strain-hardens at higher strain amplitudes (∆ε/2/>1.1%) and cyclic strain-softens at lower strain amplitudes (∆ε/2<1.1%). A linear relationship between the degree of cyclic strain-hardening and the strain amplitude has been established for higher strain amplitudes. Fatigue-ductility and fatigue-strength properties agree with those found in the open literature for the same loading conditions.