Browsing by Issue Date, starting with "2018-08"
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- Biomechanical performance of hybrid electrospun structures for skin regenerationPublication . Dias, J.R.; Baptista-Silva, S.; Sousa, A.; Oliveira, A. L.; Bártolo, P. J.; Granja, P. L.Wound dressings made by electrospun nanofibers have been demonstrating great potential to regenerate skin tissue as compared to the conventional membrane products available in the market. Until today most of the developed dressings have only demonstrated the capability to regenerate the dermis or epidermis. In this study we propose new hybrid electrospun meshes combining polycaprolactone and gelatin. Several approaches, multilayer, coating and blend were stablished to investigate the most appropriate hybrid structure with potential to promote skin regeneration in its full thickness. The structures were evaluated in terms of physico-chemical properties (porosity, water vapor permeability, contact angle and swelling degree) and according to its mechanical and biological performance. Multilayer and blend structures demonstrated to fit most of native skin requirements. However, looking to all the performed characterization we considered multilayer as the most promising hybrid structures, due its high porosity which contributed to an ideal water vapor permeability rate and good mechanical and biological properties. Based on this multilayer structure is a promisor wound dressing.
- European Respiratory Society International Congress best abstract preview from the allied respiratory professionals from assembly 9Publication . Blonshine, Jason; Cruz, Joana; Sajnic, Andreja; De Brandt, JanaThe 28th European Respiratory Society (ERS) International Congress [2018] in Paris features interesting research findings within the allied respiratory professional assembly (assembly 9). Excellent and high ranked abstracts were selected for this year’s ERS International Congress preview of assembly 9 and are put in the spotlights. A summary of the best three abstracts of every group, i.e., lung function technologists, physiotherapists and nurses, within assembly 9 is presented. Session, timing and location of the presentation of the abstract at this year’s ERS International Congress is indicated in squared brackets following the authors’ name.
- Relatório Anual (2017.2018) - 2º ano da Licenciatura em Relações Comerciais China-Países LusófonosPublication . Mangas, Catarina; Milhano, Sandrina; Almeida, AuréliaRelatório que sintetiza a forma como decorreu o ano 2017/2018, perspetivando-se como um instrumento de reflexão e análise sobre as práticas, no sentido de apontar direções para a melhoria da qualidade do processo de ensino-aprendizagem e do consequente aumento de competências por parte dos estudantes.
- A mm Wave solution to provide wireless Augmented Reality in classroomsPublication . Gomes, Rodolfo; Sismeiro, Luis; Ribeiro, Carlos; Sanchez, Manuel G.; Hammoudeh, Akram; Caldeirinha, Rafael F. S.This paper presents a very high throughput wireless data transmission solution for Augmented Reality (AR) Head Mounted Devices (HMDs) in the 60 GHz band. Its feasibility is assessed in an Orthogonal Frequency Division Multiplexing (OFDM) downlink communication towards five User Equipment (UE) devices, placed at different locations inside an indoor classroom environment scenario. Key Performance Indicators (KPIs) as Error Vector Magnitude (EVM), Signal-to-Noise Ratio (SNR), and path loss are considered for Quality of Service (QoS) assessment. Experimental results demonstrate the reliability of the proposed mmWave system, where a data rate of 312.5 Mbps is achieved over distances of 1, 2.4 and 4.1 m, regardless the UE position.
- Formation of intermetallic structures at the interface of steel-to-aluminium explosive weldsPublication . Carvalho, G.H.S.F.L.; Galvão, I.; Mendes, R.; Leal, Rui; Loureiro, A.The formation of intermetallic structures at the interface of carbon steel to 6082 aluminium alloy explosive welds and their influence on the weldability of these two materials were studied. The morphology, the microstructure, the chemical and phase compositions of the welds were characterised by several types of microscopy techniques. The interface characterisation proved that explosive mixtures with a lower detonation velocity were revealed as being more suitable for achieving consistent welds since jet entrapment was prevented and continuous molten layers were not formed at the weld interface. It was also found that the physical properties of the intermetallic phases generated at the weld interface have a strong influence on the weldability of steel-to-aluminium explosive welds. Specifically, it was shown that the formation of aluminium-rich intermetallic phases at the weld interface increases the solidification time of the interfacial molten material, decreasing the weldability of these two materials. The formation of these intermetallic compounds should be avoided by reducing the interaction between the flyer and the baseplate as well as by avoiding excessive molten layers.
- A Two-Stage Approach for Robust HEVC Coding and StreamingPublication . Carreira, João F. M.; Assunção, Pedro; Faria, Sergio; Ekmekcioglu, Erhan; Kondoz, AhmetThe increased compression ratios achieved by the High Efficiency Video Coding (HEVC) standard lead to reduced robustness of coded streams, with increased susceptibility to network errors and consequent video quality degradation. This paper proposes a method based on a two-stage approach to improve the error robustness of HEVC streaming, by reducing temporal error propagation in the case of frame loss. The prediction mismatch that occurs at the decoder after frame loss is reduced through the following two stages. First, at the encoding stage, the reference pictures are dynamically selected based on constraining conditions and Lagrangian optimization, which distributes the use of reference pictures, by reducing the number of prediction units that depend on a single reference. Second, at the streaming stage, a motion vector (MV) prioritization algorithm, based on spatial dependencies, selects an optimal subset of MVs to be transmitted, redundantly, as side information to reduce mismatched MV predictions at the decoder. The simulation results show that the proposed method significantly reduces the effect of temporal error propagation. Compared with the reference HEVC, the proposed reference picture selection method is able to improve the video quality at low-packet-loss rates (e.g., 1%) using the same bitrate, achieving quality gains up to 2.3 dB for 10% of packet loss ratio. It is shown, for instance, that the redundant MVs are able to boost the performance achieving quality gains of 3 dB when compared with the reference HEVC, at the cost using 4% increase in total bitrate.
- Rutura e transmutação. Aplicabilidade de técnicas do treino do ator na recuperação de sequelas de AVCPublication . Reis, Daniela Maria Morganiça; Mendonça, Guilherme Abel FerreiraEsta dissertação trata das contribuições possíveis do treino de ator na recuperação do Acidente Vascular Cerebral (AVC). É definida a patologia AVC e são enumeradas as causas, os fatores de risco, as tipologias e sequelas prováveis, bem como as terapias mais comuns. É feita depois uma descrição generalizada do treino de ator assim como um levantamento de algumas técnicas passiveis de serem usados na recuperação de pessoas que sofreram um AVC. Recorre-se a um estudo de caso de carácter limitado e experimental numa tentativa de melhor aferir o potencial deste tipo de intervenção. Este estudo de caso conta, porém, com apenas um participante. Um capítulo final sobre um possível percurso metodológico é ainda apresentado, e reúne uma série de considerações sobre a aplicabilidade do uso de técnicas do treino do ator. Propõe, de igual forma, um modelo a seguir numa futura investigação mais otimizada.
- Marine invasive macroalgae: Turning a real threat into a major opportunity - the biotechnological potential of Sargassum muticum and Asparagopsis armataPublication . Pinteus, Susete; Lemos, Marco F.L.; Alves, Celso; Neugebauer, Agnieszka; Silva, Joana; Thomas, Olivier P.; Botana, Luis M.; Gaspar, Helena; Pedrosa, RuiMarine invasive species are widely recognized as one of the worst threats to marine ecosystems integrity, un-balancing native communities, which may lead to paramount ecological and economic impacts. Within invasiveseaweeds, Sargassum muticum and Asparagopsis armata are recognized as successful invaders in Europe andAmerica. Despite several attempts to control the spread of marine invaders, until now, all have proven to beelusive, and therefore, alternative strategies should be embraced.Worldwide, seaweeds have been increasingly explored due to their ability to produce bioactive compounds.However, one of the main problems associated with the production/extraction of these bioactive compounds fornew products development, is the source availability and the potential negative environmental consequences ofthis exploitation.Within this framework, the use of invasive species to obtain natural bioactive compounds presents us with atwo-folded opportunity - high availability of the biological material for the extraction of unique bioactivecompounds for new products development, and through specimen collection, mitigating negative effects causedby alien species, contributing for ecosystem integrity and sustainability.Over the last decades, the brown seaweed S. muticum and the red A. armata have been studied all over theworld for their capacity to produce bioactive compounds, with main results pointing towards their high potentialas producers of antioxidant, antifouling, antimicrobial, and antitumor compounds.The present review summarizes the biotechnological potential of S. muticum and A. armata as producers ofbioactive compounds, while addressing the potential use of global threats as important blue growth pawns.
- The Nine Lemma and the push forward construction for special Schreier extensions of monoids with operationsPublication . Martins-Ferreira, Nelson; Montoli, Andrea; Sobral, ManuelaWe show that the Nine Lemma holds for special Schreier extensions of monoids with operations. This fact is used to obtain a push forward construction for special Schreier extensions with abelian kernel. This construction permits to give a functorial description of the Baer sum of such extensions.
- Digitally Signed and Permission Restricted PDF FilesPublication . Domingues, Patrício; Frade, MiguelThe PDF format is the de-facto standard for many types of documents. Often a forensic digital investigation is faced with a significant volume of PDF files. It is thus important to filter PDF files, giving priority to files that have an high probability to carry important and meaningful data. In this paper, we focus on identifying potential important PDF files, selecting i) digitally signed files and ii) files that have special owner restrictions set, such as interdiction to assemble/separate pages. For this purpose, we present the python-based digiSign|protectedPDF module for the open source Autopsy forensic software. When run over a digital forensic data source, the module creates two lists: one holding the digitally signed files and, another one with files that have special restrictions in their usage. To study the occurrence of digitally signed and of permission-protected PDF and their importance for digital forensics, we analyzed a Windows 10 forensic image, finding that 2.81% of the PDF files were digitally signed and 3.75% were permission-protected. The study shows that digitally signed PDF files can harbor meaningful data for a digital forensic investigation.