Browsing by Issue Date, starting with "2017-03"
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- Bioactivity gradients of cytoprotective and anticancer catechins in skin: Simulation studies for the design of controlled release systemsPublication . Silva, João; Videira, Paula; Lagoa, RicardoDermal delivery of catechins may be an effective approach for protection of skin against inflammation, aging and cancer caused by exposure to radiation and environmental toxicants. Catechins are flavonoid-type polyphenols showing capacity to attenuate UV-induced skin injury, carcinogenesis and melanoma metastasis, but the prevalence of beneficial effects depends on compound concentration. In this work, catechin penetration through the skin was simulated to predict the concentration in different layers: stratum corneum, viable epidermis and dermis. By combining these results with expected dose-effect relationships of the compounds, bioactivity profiles were calculated for relevant skin regions. Since the concentration dependences of catechin capacities to protect dermal fibroblasts and to inhibit melanoma cells (data aggregated from published literature) follow different types of dose-effect curves, bioactivity profiles in the skin can be different, even for the same delivery conditions. This method allows to estimate the delivery conditions (time and concentrations) required to achieve the desired biological/pharmacological activities at critical skin strata, namely, viable epidermis and dermis where metastatic melanoma cells and susceptible fibroblasts localize. The work suggests a framework to support the rational design of controlled release systems of topically applied bioactive compounds in therapeutic and investigative delivery.
- What is an ideal a zero-class of?Publication . Martins-Ferreira, Nelson; Montoli, A.; Ursini, A.; Linden, T. Van derWe characterise, in pointed regular categories, the ideals as the zero-classes of surjective relations. Moreover, we study a variation of the Smith is Huq condition: two surjective left split relations commute as soon as their zero-classes commute.
- Improved displacement based alternative to force based finite element for nonlinear analysis of framed structuresPublication . Ferreira, Miguel; Providência, Paulo; Gala, Pedro; Almeida, JoãoThis paper presents an improved displacement based element (iDBE) for nonlinear finite element analysis of framed structures, which, like the force based elements (FBE), needs neither high order shape functions nor the refinement of the finite element mesh in straight members to attain an accurate solution. To achieve this objective, to the strain fields based on the displacements shape functions of the conventional displacement based element (cDBE) corrective fields are added, which are determined at the element level by the principle of virtual forces. Simple examples involving tapered elements, nonlinear axialbending interaction and elasto-plastic behavior, are included to illustrate the application of iDBE and compare its performance to cDBE and FBE.
- Assessement and management of environmental quality conditions in marine sandy beaches for its sustainable use—Virtues of the population based approachPublication . Gonçalves, Sílvia C.; Marques, João C.Sandy beaches constitute high natural value ecosystems which have been worldwide a target for growing human activities and ensuing pressures in the last decades, which caused ecological damages on these environments and led to its environmental quality decline. However, little is known about the responses of these ecosystems to distinct stressors and pressures, and holistic and integrated coastal management actions that protect beach environments and their ecological processes are yet to be developed. The aim of this viewpoint article is to present and discuss the utility of using a population approach to macrofaunal key species as a helpful tool for the assessment, management, and sustainable use of sandy beaches. The role of macrofaunal key species as indicators of environmental changes and of ecological quality condition is discussed and illustrated by some practical examples from the literature. The population is presented as a highly relevant ecological unit in management and one of the easiest ones to use, responding more rapidly to disturbances in the ecosystem than the most complex units. In this context, bio-ecology and population dynamics models are presented as tools and their potential, to improve the way we assess and manage ecological quality conditions of beach ecosystems aiming at its sustainable use, are discussed. Also, the advantages and drawbacks of the use of these tools in the population approach are evaluated. Monitoring, assessment and management practices focusing on beach key species bioecology as ecological indicator hold large potential in nowadays fast changing scenario, and should be encouraged as a function of their identifiable responses to manmade and natural disturbances.
- Fundamental solutions of the time fractional diffusion-wave and parabolic Dirac operatorsPublication . Ferreira, Milton; Vieira, Nelson Felipe LoureiroIn this paper we study the multidimensional time fractional diffusion-wave equation where the time fractional derivative is in the Caputo sense with order . Applying operational techniques via Fourier and Mellin transforms we obtain an integral representation of the fundamental solution (FS) of the time fractional diffusion-wave operator. Series representations of the FS are explicitly obtained for any dimension. From these we derive the FS for the time fractional parabolic Dirac operator in the form of integral and series representation. Fractional moments of arbitrary order are also computed. To illustrate our results we present and discuss some plots of the FS for some particular values of the dimension and of the fractional parameter.
- Bioengineered Temporomandibular Joint Disk Implants: Study Protocol for a Two-Phase Exploratory Randomized Preclinical Pilot Trial in 18 Black Merino Sheep (TEMPOJIMS)Publication . Ângelo, David Faustino; Monje, Florencio Gil; González-García, Raúl; Little, Christopher B; Mónico, Lisete; Pinho, Mário; Santos, Fábio Abade; Carrapiço, Belmira; Gonçalves, Sandra Cavaco; Morouço, Pedro; Alves, Nuno; Moura, Carla; Wang, Yadong; Jeffries, Eric; Gao, Jin; Sousa, Rita; Neto, Lia Lucas; Caldeira, Daniel; Salvado, FranciscoBackground: Preclinical trials are essential to test efficacious options to substitute the temporomandibular joint (TMJ) disk. The contemporary absence of an ideal treatment for patients with severe TMJ disorders can be related to difficulties concerning the appropriate study design to conduct preclinical trials in the TMJ field. These difficulties can be associated with the use of heterogeneous animal models, the use of the contralateral TMJ as control, the absence of rigorous randomized controlled preclinical trials with blinded outcomes assessors, and difficulties involving multidisciplinary teams. Objective: This study aims to develop a new, reproducible, and effective study design for preclinical research in the TMJ domain, obtaining rigorous data related to (1) identify the impact of bilateral discectomy in black Merino sheep, (2) identify the impact of bilateral discopexy in black Merino sheep, and (3) identify the impact of three different bioengineering TMJ discs in black Merino sheep. Methods: A two-phase exploratory randomized controlled preclinical trial with blinded outcomes is proposed. In the first phase, nine sheep are randomized into three different surgical bilateral procedures: bilateral discectomy, bilateral discopexy, and sham surgery. In the second phase, nine sheep are randomized to bilaterally test three different TMJ bioengineering disk implants. The primary outcome is the histological gradation of TMJ. Secondary outcomes are imaging changes, absolute masticatory time, ruminant time per cycle, ruminant kinetics, ruminant area, and sheep weight Results: Previous preclinical studies in this field have used the contralateral unoperated side as a control, different animal models ranging from mice to a canine model, with nonrandomized, nonblinded and uncontrolled study designs and limited outcomes measures. The main goal of this exploratory preclinical protocol is to set a new standard for future preclinical trials in oromaxillofacial surgery, particularly in the TMJ field, by proposing a rigorous design in black Merino sheep. The authors also intend to test the feasibility of pilot outcomes. The authors expect to increase the quality of further studies in this field and to progress in future treatment options for patients undergoing surgery for TMJ disk replacement. Conclusions: The study has commenced, but it is too early to provide results or conclusions.
- POLÍTICAS LOCAIS E IMPACTOS NA CONCEÇÃO DA EXPERIÊNCIA TURÍSTICA EM ESPAÇOS URBANOS – OS CASOS DO BAIRRO ALTO E DA MOURARIA, LISBOAPublication . Xavier, António José Tavares da Costa; Almeida, António Sérgio Araújo deA reabilitação urbana do património arquitetónico e monumental em bairros históricos tende a propiciar a disputa na utilização/apropriação dos “novos” espaços daí resultantes, não só por novos moradores, normalmente de classes sociais mais abastadas, mas também por novos comerciantes, mais especializados em contextos empresariais. Surgem, assim, novos espaços de residência, lazer, entretenimento e cultura, entre outros. Apurar contributos locais para que bairros típicos proporcionassem experiências locais e turísticas diferenciadas na perspetiva da fidedignidade às origens foi um dos grandes objetivos deste trabalho. Paradoxalmente, conforme observado na cidade de Lisboa e após uma investigação realizada em 2014 e 2015, a mesma governação local de reabilitação urbana suscita ambivalências a vários níveis. Por um lado, promovendo identidades e valores que caracterizam objetivamente a Tradição e a História num regime de reciprocidade com os habitantes locais, e, por outro lado, transformando espaços onde os valores culturais se assumem numa função comercial sem correspondência nas expectativas das gentes locais nem coerência com a autenticidade (resultante dos valores identitários) dos respetivos espaços. Enquanto no Bairro Alto permitiuse aos investidores a decisão na apropriação e utilização do espaço, na Mouraria, registou-se um processo de governação integrada com a mobilização da população residente e forças ativas do bairro. No primeiro caso, surgiram conflitos entre novos e velhos utilizadores do bairro, assumindo-se a oferta turística como espaço de animação noturna centrada num espaço público de boémia, no consumo de álcool e num ambiente de festa permanente No segundo caso, geraram-se sinergias propiciadoras de uma reabilitação urbana defensora da mobilização das estruturas identitárias do bairro, promovendo estilos de vida tradicionais e resgatando o seu imaginário coletivo assente nos seus próprios sistemas de valores. Na Mouraria, observa-se um Turismo comunitário, envolvendo gentes locais, que, apropriando-se do seu espaço turístico, o projetam no pressuposto de consubstanciar objetivamente o seu património numa experiência turística diferenciada.
- Additive manufacturing tooling for the automotive industryPublication . Leal, Rui; Barreiros, F. M.; Alves, L.; Romeiro, F.; Vasco, J. C.; Santos, M.; Marto, C.Automotive industry faces new challenges every day, new design trends and technological deployments from research push companies to develop new models and facelifts in short term, requiring new tools or tool reshaping. Concerning the current world economic scenario, decreasing time for tooling up becomes as important as decreasing time-to-market. Such scenario opens up the horizons for new manufacturing approaches like additive manufacturing, in this case, applied for tooling up a stamping process on the automotive industry for the production of body panels. This approach enables the manufacturing of stamping inserts using similar high performance alloy steel as in conventional tooling, therefore, without losing tool mechanical properties. The stamping tools produced were tested by an automotive company in order to determine tool behaviour under real operating conditions, considering the high level demands of the stamping process. The results obtained enabled to conclude that metal additive manufacturing provided tools for the stamping process with excellent performance with a significant decrease on time-to-tooling.
- Enabling spatial diversity and beamsteering with reduced RF-chains using reconfigurable transmitarraysPublication . João R. Reis; Caldeirinha, Rafael F. S.; Fernandes, Telmo R.; Hammoudeh, AkramThis manuscript introduces a new vision on the implementation of spatial diversity with beamsteering capability, by suppressing the typical beamforming networks of antenna phased arrays and replace them by Reconfigurable Transmitar- rays. Consequently, the radio frequency components, i.e. RF- chains that compose such systems, were replaced by a device with the capability to perform two-dimensional beamsteering relying on single antenna source, hence reducing the number of associated RF hardware in comparison with traditional phased array systems. By spatially distributing side-by-side more than one device, spatial diversity with beamsteering is enabled with an estimated reduction of 1:8 in the number of associated RF-chains. This new concept clearly demonstrates its merit by directly reducing the implementation costs„ RF-chain components and increasing the energy efficiency, specially in larger systems.
- Characterization of wireless propagation through traditional Iberian brick wallsPublication . Ferreira, David; Caldeirinha, Rafael F. S.; Fernandes, Telmo R.; Cuinas, InigoThis paper presents the wireless transmission properties for brick walls with different thicknesses and facade finish coatings. The ceramic hollowed bricks under study are traditionally employed in the Iberian residential construction, where the 11, 15 and 20 cm thicknesses are most common in indoor and outdoor walls. For each brick dimension, three different prototypes were manufactured varying in the type of wall finish, i.e.: naked brick, smooth painted plaster and rough painted plaster. The prototypes were measured in an anechoic chamber at frequencies ranging from 680MHz up to 10GHz. Results demonstrate that the brick wall internal heterogeneity, as well as the type of finish, significantly influence the frequency response of the walls.