406 research outputs found

    Fabrico rápido de implantes ósseos personalizados

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    Actualmente existem situações clínicas específicas relacionadas com perdas ou correcções ósseas significativas, cuja solução dificilmente poderá ser alcançada com implantes ou próteses disponíveis comercialmente, sendo necessário o recurso a soluções personalizadas (ditas customizadas), isto é, implantes que são concebidos e fabricados em função das especificidades do paciente. Neste sentido, o desenvolvimento de uma nova metodologia que permita o fabrico rápido de implantes ósseos em simultâneo com o acto cirúrgico poderá apresentar vantagens significativas, pois permite ao cirurgião corrigir ou alterar a geometria do implante em função de uma qualquer ocorrência anómala detectada já durante a cirurgia. A abordagem neste trabalho passou pelo desenvolvimento de uma aplicação informática que permitisse integrar numa única plataforma um conjunto de ferramentas como scanner 3D, sistema de fabrico assistido por computador (CAM) e fabrico em máquinas controladas por computador (CNC) para assim fabricar de forma rápida um implante adaptado à anatomia do paciente. O método estabelecido assentou em quatro etapas essenciais: a primeira consiste na captação da geometria do implante, realizada localmente pelo cirurgião e não envolve meios computacionais. A segunda consiste na obtenção do modelo virtual da geometria do implante, realizada a partir do levantamento de forma do modelo obtido na etapa anterior, utilizando um scanner 3D por laser. A terceira etapa consiste na utilização de um sistema CAM para a elaboração do programa de maquinagem do implante. Na quarta e última etapa materializa- se o fabrico do implante numa fresadora CNC. O sistema desenvolvido permitiu integrar recursos e tecnologias cuja utilização exige conhecimentos muito especializados, mas inseridos num ambiente amigável para o utilizador possibilita que estes possam ser utilizados por pessoas não profundamente conhecedoras das tecnologias integradas. A solução implementada revelou-se mais acessível ao nível dos custos de aquisição das tecnologias de suporte e da facilidade de utilização quando comparada com outros processos de fabrico de implantes customizados, nomeadamente os obtidos a partir de informação gerada por tomografia computorizada (TAC)

    Ensaios de integridade estrutural de placas angulares de fixação de fracturas ósseas do fémur

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    Neste trabalho descreve-se o projecto de um dispositivo mecânico desenvolvido para a realização de ensaios segundo a norma ASTM F384-00 (2000) de placas de osteossíntese anguladas. O dispositivo foi objecto de uma análise estrutural usando o método dos elementos finitos. Algumas placas foram ensaiadas estaticamente e suas características mecânicas, de acordo com a norma, determinadas

    Chronic hemolytic anemia is associated with a new glucose-6-phosphate dehydrogenase in-frame deletion in an older woman

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    Glucose-6-phosphate dehydrogenase (G6PD) deficiency, an X-linked disorder, is usually observed in hemizygote males and very rarely in females. The G6PD class 1 variants, very uncommon, are associated with chronic hemolytic anemia. Here we report a Portuguese woman who suffered in her sixties from a chronic hemolytic anemia due to G6PD deficiency. Molecular studies revealed heterozygosity for an in-frame 18-bp deletion, mapping to exon 10 leading to a deletion of 6 residues, 362-367 (LNERKA), which is a novel G6PD class 1 variant, G6PD Tondela. Two of her three daughters, asymptomatic, with G6PD activity within the normal range, are heterozygous for the same deletion. The patient's leukocyte and reticulocyte mRNA studies revealed an almost exclusive expression of the mutant allele, explaining the chronic hemolytic anemia. Patient whole blood genomic DNA HUMARA assay showed a balanced pattern of X chromosome inactivation (XCI), but granulocyte DNA showed extensive skewing, harboring the mutated allele, implying that in whole blood, lymphocyte DNA, with a very long lifetime, may cover up the current high XCI skewing. This observation indicates that HUMARA assay in women should be assessed in granulocytes and not in total leukocytes

    Re-Design de tecidos estreitos para aplicações inovadoras

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    O conceito de qualidade de vida surge pela primeira vez em 1920, através do economista inglês Arthur Cecil Pigou, que utiliza este termo para descrever o impacto governamental sobre a vida das pessoas mais desfavorecidas. Com a instalação de uma era industrializada e com o fim da 2º Guerra Mundial, a sociedade mudou de paradigma e iniciou uma procura incessante de formas para melhorar a sua qualidade de vida. Este conceito desenvolve-se juntamente com o desenvolvimento do conceito de educação, saúde, habitação, transporte, trabalho e lazer, bem como indicadores do aumento da esperança de vida, a diminuição da mortalidade infantil e dos níveis de poluição. O avanço da tecnologia teve um papel fundamental para a evolução desses conceitos, bem como o Design na procura de soluções para aplicação dessas mesmas tecnologias. No caso concreto da indústria tèxtil, a tendência é o desenvolvimento de têxteis inteligentes envolvendo a engenharia electrónica no seu processo de conceptualização e de fabrico. A chamada tecnologia wearable abre novos horizontes para a criação de soluções inovadoras, abrindo novos nichos de mercado com elevado valor acrescentado. Existem atualmente vários produtos no mercado cuja funcionalidade e utilidade lhes conferiu um estatuto imutável ao longo dos anos, onde a evolução não avançou na tendência atual. Esse é o caso dos tecidos estreitos, cuja funcionalidade poderá adquirir novas capacidades e ser utilizada em diferentes componentes têxteis nas mais variadas áreas. Essas capacidades poderão ser acrescentadas pela incorporação de materiais com luminosidade (Led’s e L-Wire) nas suas estruturas. Neste estudo realizado o design de produtos com novas funcionalidades, adaptando as tecnologias até agora desenvolvidas em novas soluções e/ou novas recriações de produto.The concept of quality of life appears in 1920, through the british economist Arthur Cecil Pigou, who uses this term to describe the government's impact on the lives of the most underprivileged. With the installation of the industrialized era and the end of the World War two, the society changed the paradigm and began a constant search for ways to improve their quality of life. This concept is developed along with the development of the concept of education, health, housing, transportation, work and leisure, as well as indicators of increased life expectancy and decreased infant mortality. The evolution of technology had played a key role in the evolution of these concepts as well as the Design in finding solutions for application of these technologies. In the case of the textile industry the trend is the development of smart textiles involving electronic engineering in the process of conceptualizing and manufacturing. The result is the wearable technology that open new horizons for creating new solutions, opening new market niches with high added value. Currently there are several products on the market whose functionality and utility gave them an immutable status over the years, and the product evolution has not advanced in the current trend. This is the case of ribbon, whose functionality can acquire new skills and be used in different textile components in various areas. These capabilities may be added by the incorporation and variation of color. As an example with the ability to become photochromatic materials (with a variation of light), thermochromic (with temperature variation), electrochromic (with electricity variance) mecanic-chromic (with voltage variation and / or strain) and also the possibility of incorporating luminescent coatings and the incorporation of luminescent materials in the structure. In this study will be developed an product design with new features and adapt the technologies so far developed in new solutions and / or new product recreationsEste trabalho foi desenvolvido no âmbito do projeto n.º 2014/37658 “NarrowTECH – Tecidos estreitos multifuncionais “, liderado pela empresa IDEPA e co-financiado pelo Fundo Europeu de Desenvolvimento Regional FEDER, através do COMPETE – Programa Operacional Fatores de Competitividad

    Physical oceanography of the western Iberia ecosystem: latest views and challenges.

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    The present review is focused on the mesoscale physical processes recognized in the Western Iberia Ecosystem, complementing earlier reviews dedicated to larger scales. Recent studies support the idea that the mesoscale processes, superimposed on the larger scale variability, are the major factor controlling the ecosystem functioning in the region. A complex structure of interleaved alongshore slope, shelf and coastal currents that interact with eddies, buoyant plumes, upwelling filaments and fronts, surface layer expressions of the subsurface circulation and internal waves is revealed by the latest research. All of these contribute in different ways to have an effect on the ecosystem. The supposedly less variable winter circulation also exhibits significant mesoscale activity, in the form of eddy shedding from the poleward slope current, intermittent upwelling events and transient nearshore poleward flows. The present incomplete knowledge of this complex system presents a number of challenges and questions that must be addressed if we are to arrive at a satisfactory understanding and predictive capability for the system as a whole

    Cistercian Pavements from Santa Maria de Alcobaça Abbey: first examples of tin-glazed tiles in Portugal

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    The Mosteiro de Alcobaça (Alcobaça Monastery, founded in 1153) was built to the image of Clairvaux Abbey, founded by the Cistercian abbot St. Bernard. In many ways Alcobaça mirrored the original concepts of the Cistercian Order, with an austere architectural style and shedding signs of richness. The glazed tiles found on the pavement of the deambulatory and some adjacent chapels are some of the first examples of lead-tin glazes in Christian Portugal. For the first time, these tiles were analytically characterized, to determine their chemical composition, production technology and decoration technique. The analytical techniques used were μ-PIXE (particle-induced X-ray emission), SEM-EDS (scanning electron microscopy with energy-dispersive X-ray spectrometry), and μ-Raman spectroscopy

    Study of the potential employment of Malvaceae Species in composites materials

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    The employ of vegetal fibers for textiles and composites represents a great potential in economic and social sustainable development. Some Malvaceae species are considered tropical cosmopolitans, such as from Sida genus. Several species of this genus provide excellent textile bast fibers, which are very similar in qualities to the jute textile fiber. The objective of the present study is present the physicochemical characterization of six Brazilian vegetal fibers: Sida rhombifolia L.; Sida carpinifolia L. f.; Sidastrum paniculatum (L.) Fryxell; Sida cordifolia L.; Malvastrum coromandelianum (L.) Gurck; Wissadula subpeltata (Kuntze) R.E.Fries. Respectively the two first species are from Brazilian Atlantic Forest biome and the four remaining from Brazilian Cerrado biome, despite of present in other regions of the planet. The stems of these species were retted in water at 37oC for 20 days. The fibers were tested in order to determine tensile rupture strength, tenacity, elongation, Young’s modulus, cross microscopic structure, Scanning Electronic Microscopy (SEM), regain, combustion, acid, alkali, organic solvent and cellulase effects, pH of the aqueous extract, Differential Scanning Calorimetry (DSC) and Thermogravimetric Analysis (TGA). The obtained values were compared with those from fibers of recognized applicability in the textile industry including hemp. The results are promising in terms of their employment in thermoset and thermoplastic medium resistance composites.FAPESP (“Fundação de Amparo à Pesquisa do Estado de São Paulo”), CAPES (Coordenação de Aperfeiçoamento de Pessoal de Nível Superior) and CNPq (“Conselho Nacional de Desenvolvimento Científico e Tecnológico”) are gratefully acknowledged. The authors would also like to thank Mr. Ervin Sriubas Jr. and Kellinton José Mendonça Francisco for their technical support

    Green chemistry and biorefineries: common future?

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    Green Chemistry and Biorefinery concepts are two approaches helping to develop new and more sustainable processes.The implementation of both methodologies impels to fossil-independent future with bioeconomy based on natural feedstock like biowaste and industrial by-products. The development of technologies for valorisation of these resources is a key role of society in the creation of sustainable and more environmentally friendly future. Shortly after the Rio Declaration on Environment and Development, Anastas and Warner presented 12 Principles of Green Chemistry but more a decade before Trevor Kletz in his Jubilee lecture entitled “What you don’t have, can’t leak” draw the frames in which scientific and industrial work should be performed. This basis of green chemistry created a fundament for further development and implementation of Anastas and Warner principles of green chemistry. One of these frames is integration of green chemistry principles in the biorefinery concept. The biorefinery is an industrial facility (or network of facilities) that cover an extensive range of combined technologies aiming to full sustainable transformation of biomass into their building blocks with the concomitant production of biofuels, energy, chemicals and materials, preferably of value added products. One of the principles of green chemistry is the use of more sustainable solvents. Some examples of them are ionic liquids (ILs) and supercritical fluids (scF). This work will demonstrate the successful examples of lignocellulosic biomass valorisation using green solvents answering the question regarding the feasibility of future biorefineries made in a greener manner

    Geologia Sul Portuguesa, com ênfase na estratigrafia, vulcanologia física, geoquímica e mineralizações da faixa piritosa

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    O presente trabalho resulta da adaptação e actualização do artigo «O Complexo Vulcano--Sedimentar da Faixa Piritosa: Estratigrafia, Vulcanismo e Mineralizações Associadas no Contexto da Zona Sul Portuguesa» de autoria de Oliveira et al., inserido no Livro Geologia de Portugal no Contexto da Ibéria, editado por Rui Dias, Alexandre Araújo, Pedro Terrinha e Carlos Kulberg e publicado pela Universidade de Évora, em 2006, durante o VII Congresso Nacional de Geologia

    Worldwide evaluation of CAMS-EGG4 CO<sub>2</sub> data re-analysis at the surface level

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    This study systematically examines the global uncertainties and biases in the carbon dioxide (CO(2)) mixing ratio provided by the Copernicus Atmosphere Monitoring Service (CAMS). The global greenhouse gas re-analysis (EGG4) data product from the European Centre for Medium-Range Weather Forecasts (ECMWF) was evaluated against ground-based in situ measurements from more than 160 of stations across the world. The evaluation shows that CO(2) re-analysis can capture the general features in the tracer distributions, including the CO(2) seasonal cycle and its strength at different latitudes, as well as the global CO(2) trend. The emissions and natural fluxes of CO(2) at the surface are evaluated on a wide range of scales, from diurnal to interannual. The results highlight re-analysis compliance, reproducing biogenic fluxes as well the observed CO(2) patterns in remote environments. CAMS consistently reproduces observations at marine and remote regions with low CO(2) fluxes and smooth variability. However, the model’s weaknesses were observed in continental areas, regions with complex sources, transport circulations and large CO(2) fluxes. A strong variation in the accuracy and bias are displayed among those stations with different flux profiles, with the largest uncertainties in the continental regions with high CO(2) anthropogenic fluxes. Displaying biased estimation and root-mean-square error (RMSE) ranging from values below one ppmv up to 70 ppmv, the results reveal a poor response from re-analysis to high CO(2) mixing ratio, showing larger uncertainty of the product in the boundaries where the CAMS system misses solving sharp flux variability. The mismatch at regions with high fluxes of anthropogenic emission indicate large uncertainties in inventories and constrained physical parameterizations in the CO(2) at boundary conditions. The current study provides a broad uncertainty assessment for the CAMS CO(2) product worldwide, suggesting deficiencies and methods that can be used in the future to overcome failures and uncertainties in regional CO(2) mixing ratio and flux estimates
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