Browsing by Issue Date, starting with "2017-04"
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- Gold nanoparticles deposited on surface modified carbon xerogels as reusable catalysts for cyclohexane C-H activation in the presence of CO and waterPublication . Ribeiro, Ana Paula da Costa; Martins, Luisa; Carabineiro, Sonia Alexandra Correia; Figueiredo, José; Pombeiro, ArmandoThe use of gold as a promotor of alkane hydrocarboxylation is reported for the first time. Cyclohexane hydrocarboxylation to cyclohexanecarboxylic acid (up to 55% yield) with CO, water, and peroxodisulfate in a water/acetonitrile medium at circa 50 °C has been achieved in the presence of gold nanoparticles deposited by a colloidal method on a carbon xerogel in its original form (CX), after oxidation with HNO3 (-ox), or after oxidation with HNO3 and subsequent treatment with NaOH (-ox-Na). Au/CX-ox-Na behaves as re-usable catalyst maintaining its initial activity and selectivity for at least seven consecutive cycles. Green metric values of atom economy or carbon efficiency also attest to the improvement brought by this novel catalytic system to the hydrocarboxylation of cyclohexane. View Full-Text
- Interpretation of medical images: end of subjectivity?Publication . Almeida, Ana; Vieira, Lina; Figueiredo, Sérgio; Rodrigues, José AlbertoIn medicine, images are often used in order to obtain a diagnosis. Among the innumerable images those from optical microscopy, such as the blood smears, and the computational ones such as renal scintigraphy. Blood smears allow identification and categorization of conditions that affect blood cells, as well as identification of microorganisms. An incorrect interpretation of images can have implications in the diagnosis and evaluation of therapeutic efficacy. Renal scintigraphy is an imaging method of Nuclear Medicine that allows the study of renal dimension and location, evaluation of the renal cortex, and the presence of renal cortical scarring as a consequence of irreversible kidney damage after a urinary infection. The importance in the analysis and interpretation of these studies is related with diagnosis and follow-up of renal pathologies, as well as to the therapeutic decision. However, it is known that there are currently some limitations in the detection of renal scars, which are caused by factors such as: physical, instrumental, and patient-related. The interpretation of either blood smears or renal scintigraphy is associated with training and expertise. These are allied to the subjectivity of the observer, being a limitation in the quality and reproducibility of the results.
- A novel finite element formulation for the buckling analysis of layered composite beam structuresPublication . Santos, Hugo A.F.A.A novel finite element formulation for the buckling analysis of two-layer composite beam structures will be presented. The beam elements possess a single flexible shear interface and each layer is modelled by means of Timoshenko’s theory. The formulation relies on a hybrid variational principle of complementary energy only involving force/moment-like variables as fundamental unknown fields. The approximate field variables are such that all equilibrium differential equations hold in strong form, and the inter-element equilibrium as well as the Neumann boundary conditions are enforced by means of the Lagrangian-multiplier method. The accuracy and effectiveness of the proposed formulation will be demonstrated through the analysis of several numerical tests.
- BCG-loaded chitosan microparticles: interaction with macrophages and preliminary in vivo studiesPublication . Caetano, Liliana Aranha; Figueiredo, Lara; Almeida, António J.; Gonçalves, L. M.The aim of this study was to develop a novel BCG-loaded chitosan vaccine with high association efficiency which can afford efficient interaction with APC and elicit local and Th1-type-specific immune response after intranasal administration. Chitosan-suspended BCG and BCG-loaded chitosan-alginate microparticles were prepared by ionotropic gelation. Interaction with APC was evaluated by fluorescence microscopy using rBCG-GFP. Specific immune responses were evaluated following intranasal immunization of mice. Cellular uptake was approximately two-fold higher for chitosan-suspended BCG. A single dose of BCG-loaded microparticles or chitosan-suspended BCG by intranasal route improved Th1-type response compared with subcutaneous BCG. Chitosan-suspended BCG originated the highest mucosal response in the lungs by the intranasal route. These positive results indicate that the proposed approach of whole live BCG microencapsulation in chitosan-alginate for intranasal immunization was successful in allowing efficient interaction with APC while improving the cellular immune response, which is of interest for local immunization against tuberculosis.
- Selection of modelling parameters for stochastic model updatingPublication . Silva, Tiago A. N.; Mottershead, John E.In structural dynamics, the adjustment of a set of modelling parameters based on the minimization of the discrepancy between experimental and model responses is known as model updating. In the context of stochastic model updating, the selection of a set of updating parameters from the modelling ones is very important, both in terms of computational efficiency and of the accuracy of the solution of this stochastic inverse problem. One can find in the literature several approaches to model updating. A simple expression was developed for covariance matrix correction in stochastic model updating and by its use one may observe the relevance of choosing the correct set of updating parameters. One may conclude that if the updating parameters are correctly chosen, then the covariance matrix of the outputs is correctly reconstructed, but when the updating parameters are wrongly chosen is found that the responses covariance matrix is generally not reconstructed accurately, although the reconstructing of the responses mean values is accurate. Hence, the selection of updating parameters is developed by assessing the contribution of each candidate parameter to the responses covariance matrix, thereby enabling the selection of updating parameters to ensure that both the responses mean values and covariance matrix are reconstructed by the updated model. It is shown that the scaled output covariance matrix may be decomposed to allow the contributions of each candidate parameter to be assessed. Numerical examples are given to illustrate this theory.
- Collection technique and sample processing for impression cytology of the ocular surfacePublication . Freitas, Kátia Amaral; Mendonça, PaulaIntroduction: The impression cytology of ocular surface is a minimally invasive technique that allows the analysis of conjunctival and corneal cells, as an alternative to smears and punch biopsies. These specific guidelines will help health professionals, such as nurses and doctors, to ensure better samples of ocular surface without hurting patients, and will provide a new method of fixation for impression cytology of ocular specimens. Objective: The aim of this study was to present a technique for collecting, fixing, and staining for impression cytology of ocular specimens. Materials and Methods: 50 samples of bulbar conjunctiva taken from 50 ESTeSL volunteers were analyzed. The material was collected on a strip of cellulose acetate from Millipore Corporation, then fixed on SureThin and stained with a Papanicolaou stain. The slides were analyzed by three independent evaluators, using an evaluation grid with the following parameters: cell size, detail and nuclear membrane, detail and cytoplasmic membrane, ratio N / C, and tinctorial affinity. Results: The filter paper with apex helped to correctly position the paper in the eye and the procedure that was applied allowed an effective collection of cells with 50-70% of the filter surface being filled without the need for topical anesthesia. The SureThin fixative presented quality in cell preservation, in addition to being more economical. The Papanicolaou technique proved to be ideal in the coloring of ocular epithelial cells. This developed methodology presented a response of 80, 9% to a maximum score of 2. Conclusions: The presented method proved to be very effective in evaluating ocular cell samples, while simultaneously proving to be a very cheap and comfortable technique for the patient.
- Interpretation of medical images: end of subjectivity?Publication . Almeida, Ana; Vieira, Lina; Figueiredo, Sérgio; Rodrigues, J. A.The aim of the study: To describe the importance of blood smears images, and the renal scintigraphy, in clinical diagnosis and to describe the relevant aspects that must be analyzed in such images, taking into account the reduction of the subjectivity and variability in the interpretation of the findings. Final considerations: Interpretation of either blood smears or renal scintigraphy is associated with training and expertise. These are allied to the subjectivity of the observer, is a limitation in the quality and reproducibility of the results.
- Promoting patient-centered care in chronic diseasePublication . Grilo, Ana Monteiro; Santos, Margarida Custódio dos; Gomes, Ana Isabel; Rita, Joana SantosNowadays, many people around the world are seeing their lives being shattered and even shortened due to one or more chronic conditions. Chronic illness is a dynamic ongoing process that is determined by a complexity of factors. Patient literacy, motivation, emotional well-being, and resources play an important role in patient adaption and are important challenges for healthcare providers. A systematic patient-centered approach that enables chronic patients to play an active role in their condition management and in the decision making process on a day-to-day basis is required. However, some studies show that health professionals do not always guide their actions by Patient-centered orientation, either by personal issues or by professional and/or institutional barriers. The present chapter aimed to provide a comprehensive approach to patient-centered care in chronic disease and offer a structured guideline as a tool for formal academic education in chronic patient-centered care. This chapter is structured into five sections: (1) Chronic disease: the challenge of the twenty-first century, (2) The patient with a chronic disease, (3) Patient-centered care in chronic diseases, (4) Issues and barriers to achieve patient-centered care, and (5) Guide tool for health professionals’ training and education in patient-centered care.
- As subvenções e o IVA – algumas reflexõesPublication . Gomes, Cláudia; Palma, Clotilde CeloricoO sistema comum do Imposto sobre o Valor Acrescentado (IVA) foi instituído na União Europeia (UE) para harmonizar a tributação do consumo no mercado comum, sendo considerado uma ferramenta essencial para garantir que as transações económicas de bens e serviços são realizadas de modo a não provocar distorções na concorrência. O IVA é o imposto que apresenta um maior grau de harmonização, mas ainda assim, existem áreas de menor harmonização fiscal, podendo contribuir para a lesão da sã concorrência e provocar distorções no mercado comum. O tratamento das subvenções é uma das áreas onde existem algumas questões, que podem colocar em causa o tão desejado objetivo da harmonização. Questões que começam logo pela ausência de uma definição de subvenção para efeitos de IVA, pelas múltiplas formas de subvenções existentes e múltiplos objetivos visados pela atribuição dessas subvenções aos diferentes agentes, operadores económicos e realidades nacionais. Todas estas problemáticas têm provocado constrangimentos no Direito da União Europeia, nomeadamente na aplicação da legislação europeia por parte dos Estados-membros. Constrangimentos, que têm originado conflitualidade entre os sujeitos passivos de IVA e as Autoridades Fiscais dos Estados-membros, originando vária jurisprudência, nacional e europeia. Consideramos este estudo relevante, pois permitirá identificar as áreas de maior conflito, onde a falta de conceitos claros ou a má interpretação das regras europeias, põe em causa a neutralidade, princípio nuclear deste imposto que garante o correto funcionamento do sistema comum do IVA.
- Models on variational methods for image processingPublication . Rodrigues, José AlbertoVariational image-processing models offer high-quality processing capabilities for imaging. They have been widely developed and used in the last two decades, enriching the fields of mathematics as well as information science. Mathematically, several tools are needed: energy optimization, regularization, partial differential equations, level set functions, and numerical algorithms. With this work we analyze some variational imageprocessing models.