155 research outputs found

    Parallel neural network recognition - a multi-agent system approach

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    This paper presents and discusses the design and the development of a pattern recognition agent based on neural networks. This agent is part of an intelligent navigation system, providing it with the necessary vision abilities so that it can be placed on a strange environment in order to explore and recognise its structures and specificities. Although similar, the properties of the recognised objects change through time and according to each specific environment. The flexibility required by such recognition process was implemented by several pattern recognition agents. Each agent is based on a neural network and can be trained on-line by a parallel training algorithm to allow an effective real time utilisation

    A Novel Biomanufacturing System to Produce Multi-Material Scaffolds for Tissue Engineering: Concept and Preliminary Results

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    This research work aims to validate a new system that enables the fabrication of multimaterial 3D structures using poly(e-caprolactone) and sodium alginate for potential use in Tissue Engineering applications. To produce multi-material scaffolds for Tissue Engineering, accurate techniques are needed to obtain three-dimensional constructs with clinically appropriate size and structural integrity. This paper presents a novel biomanufacturing system which can fabricate 3D scaffolds with precise shape and porosity, through the control of all fabrication modules by an integrated computational platform. The incorporation of a clean flow unit and a camera makes it possible to produce scaffolds in a clean environment and provides a monitoring tool to analyse constructs during the production, respectively.info:eu-repo/semantics/publishedVersio

    Ovarian Ectopic Pregnancy in Adolescence

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    Ovarian pregnancy is one of the rarest types of extrauterine pregnancy. Its preoperative diagnosis remains a challenge since it presents quite similarly to tubal pregnancy and complicated ovarian cysts. Although in most cases, histology is necessary to confirm the diagnosis, we present an ovarian pregnancy in a teenager, correctly diagnosed during ultrasound examination

    Traffic Vertical Signposting: Materials Characterization and Structural Numerical Simulation

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    Aknowlegements: This work was supported by the project POCI-01-0247-FEDER-010797from the Agency for Competitiveness and Innovation (IAPMEI). In addition, the authors acknowledge the funding from the project UID/Multi/04044/2013 of the Portuguese Foundation for Science and Technology (FCT) and PAMI - ROTEIRO/0328/2013 (Nº 022158).The existing metallic solutions used for vertical traffic signs are associated with higher costs and environmental issues due to their manufacturing and degradation, when compared with polymeric solutions. Thus, the development of vertical signs considering the injection from polymeric materials in order to overcome problems related with sustainability, maintenance costs, and to achieve higher resistance to corrosion assumes nowadays an important role. The use of ecofriendly and innovative products considering the industrial waste combined with synthetic polymers performing the appropriate mechanical properties, can also be studied to find out new solutions that allow to solve the aforementioned problems. Additionally, these innovative vertical signs can contribute to avoid vandalism events related with theft and graffiti activities. This work presents the prior materials investigation and the structural design of vertical signs that are intended to be produced through polymer injection. Three main steps were considered: i) materials research, ii) materials characterisation through the analysis of polycarbonate resin isolated and in different sets of mixtures with different concentrations through tensile testing and static water contact angle measurements to find the optimal material composition; and iii) structural numerical simulation considering polycarbonate resin and using the current standard EN 12899-1 [1] to compute wind resistance, temporary and permanent deflections. Both experimental and numerical results led to an optimized proposal of the vertical signposting structural design.info:eu-repo/semantics/publishedVersio

    The Use of Polypropylene and High-Density Polyethylene on Cork Plastic Composites for Large Scale 3D Printing

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    Acknowledgements This work is supported by the Fundação para a Ciência e a Tecnologia (FCT) and Centro2020 through the Project references: UID/Multi/04044/2013 and PAMI - ROTEIRO/0328/2013 (Nº 022158). In addition, the authors acknowledge the funding from the project World of Outstanding Wool and Wood (WOWW), POCI-01-0247-FEDER-017574 from the Portuguese National Innovation Agency. The authors gratefully acknowledge to Amorim Cork Composites for the cork powder. We thank Ana O. Tojeira and Ana R. Fonseca for the support provided in performing the laboratorial tests as Laboratory Managing Engineers.This work focuses on studying the possibility of 3D printing of composite materials composed by cork and a polymer matrix (CPC). Initially the cork was mixed with two types of polymers (HDPE and PP) in different proportions and later processed using extrusion and injection. The composites were tested to study the physical, chemical and mechanical properties. The material was then tested on a large-scale 3D printer to study its feasibility and the ability to produce new products through 3D printing. Attention was focused on the use of pure cork, varying the concentration of cork and coupling agent in thermoplastic matrix composites of PP and HDPE. It was demonstrated that the increase of 5wt.% of coupling agent in the two types of polymers significantly improved the mechanical properties and adhesion between the phases but the increase in cork concentration decreased mechanical properties and crystallinity. The CPCs with PP showed to have better mechanical properties, better aesthetic and internal structural quality, and easier processability than those with HDPE matrix. Nevertheless, the HDPE CPCs showed a high degree of crystallization. Concerning 3D printing, it was demonstrated the possibility of making new products based on natural cork fibers, showing promising results, although additional research is still needed to optimize the process.info:eu-repo/semantics/publishedVersio

    Effect of Tween-80 on Stability and Secretion of Hydrophobic Tagged-cutinases

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    To significantly enhance the downstream processing, two cutinase variants were constructed by genetic fusion small hydrophobic peptides (WP)2 and (WP)4, respectively. However, the fusion of these peptides impairs cutinase secretion by the host cell Saccharomyces cerevisiae and increases cutinase inactivation in the culture broth due to cutinase aggregation, resulting in cutinase activities per biomass of 56 % of cutinase-(WP)2 and of 7 % of cutinase-(WP)4, in relation to cutinase without the hydrophobic tags. It was observed that the addition of non-ionic surfactant Tween-80 into the culture broth could minimise the cutinase inactivation. The addition of Tween-80 also results in the enhancement of cutinase secretion by the yeast cell, leading to 1.25 and 2.51 fold-higher extracellular cutinase-(WP)2 and cutinase-(WP)4, respectively, in relation to cultivations performed in the absence of surfactant. Therefore, the addition of Tween-80 on the culture broth partly minimises the effect of fusion of the hydrophobic tags on the inactivation of the enzymatic activity and on the reduction of the protein secretion. By this way, the use of Tween-80 on the S. cerevisiae cultivation may contribute to the efficiency enhancement of the downstream processing of tagged cutinases
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