Extraction and quantification of perivascular spaces based on vesselness filtering: A potential biomarker for Fabry disease

Tese de mestrado integrado, Engenharia Biomédica e Biofísica (Engenharia Clínica e Instrumentação Médica), Universidade de Lisboa, Faculdade de Ciências, 2020Perivascular Spaces (PVS) allow interstitial solutes to be cleared from the brain contributing to the brain‘s homeostasis. Dysfunction of these pathways can occur if there is deposition of substances causing stagnation of fluid (CSF). Quantitative analysis of PVS on Magnetic Resonance Images (MRI) is important for understanding their relationship with dementia, stroke and vascular diseases. Manual delineation of PVS is very time consuming, and clinicians have to check multiple views in order to obtain a very accurate segmentation. Therefore, finding a method that would provide a reliable visual and quantitative information of a patient with PVS would enable a continuous monitoring giving clinical support throughout the development of each disease. Moreover, it would allow to understand and characterize PVS, provide useful insights into their role in normal brain physiology and small vessel disease (SVD). This work focused on the segmentation and further quantification of PVS in the brain using a vesselness filter (Frangi filter) . The Frangi filter, typically used to detect vessel-like or tube-like structures and fibers in volumetric image data, was capable to delineate, map and extract elongated and dot like features of PVS that were not easily seen when comparing with the non filtered images. However, this method requires a careful parameter optimization and further validation, since it presented different output behaviour in each MRI acquisition (T1-Weighted, T2-Weighted and T2-FLAIR). Also, quantitative analysis regarding the Frangi segmentation indicate that PVS visual rating scores may have a positive association with PVS volume. Statistical significance was found by clustering patients diagnosed with Multiple System atrophy (MSA), Progressive Supranuclear Palsy (PSP) and Fabry disease (FD) when compared with control patients

Projecto de implementação de um "front-end" de recepção para DAB

Mestrado em Engenharia Electrónica e TelecomunicaçõesHoje em dia, a substituição dos sistemas de emissão analógicas pelos digitais é já uma realidade. Embora o que seja mais falado actualmente relacionado com isso seja o caso da televisão, na realidade o formato de rádio digital já é uma realidade desde há algum tempo. No entanto esse sistema, apesar de já não ser propriamente novo e de ser melhor que o formato analógico, ainda não vingou no nosso país. Tal deve-se em grande parte ao elevado preço dos sistemas de recepção e a má cobertura. Então pode-se dizer que existe interesse em se efectuar um estudo que permita a concepção dos diferentes blocos necessários para a criação de um sistema de recepção mantendo o binómio qualidade/preço. Esta tese apresenta um sistema de entrada para um receptor DAB, nomeadamente o módulo do amplificador de ganho controlado seguido do módulo de conversão de frequências (misturador). ABSTRACT: Nowadays, the replacement of analog broadcast systems by digital is already a reality. Although the most talked system related with it is the television broadcasting, in fact the format of digital radio is already a reality for some time. This system isn’t new and is much better that analog broadcasting but it isn’t a successful thing in our country. This is due largely to the high price of the receiving systems. So we can say that there is interest to do a study to enable the development of the various blocks needed to create a receiving system keeping the price/quality relation. This dissertation includes a DAB front-end receiver with special focus in AGC and mixer

The importance of physical activity in the elderly population with comorbidities in a post-pandemic era

During the COVID-19 pandemic, the world faced significant challenges that impacted all age groups. Among the most vulnerable groups, the elderly population with comorbidities had the greatest challenge to their physical, social, andmental health. The lockdown imposed by health authorities aimed at slowing the spread of the virus had a large drawback in terms of the level of physical activity, risk factors, frailty, and falls risk in the elderly. Furthermore, several health issues were exacerbated, including higher levels of obesity, diabetes mellitus, dyslipidemia, cardiovascular diseases, sleep problems, and depression. A decrease in the level of physical activity was observed following quarantine, and this trend prevailed even a year after the early stages of the pandemic. A large populational study in individuals more than 65 years old showed that during the early years of the pandemic, nearly 30% of them experienced an impairment in exercise levels, which was significantly related to detriments in quality of life, and this trend prevailed even a year after the early stages of the pandemic. Given this post-pandemic scenario, it is essential that we redefine strategies to improve the quality of life of these demographics

Voltammetric growth of tin oxides in borate solution of pH 8.7

Voltammetry has been employed to study the growth of tin oxides in buffer solution of 0.3 mol L-1 H3BO3 + 0.15 mol L-1 Na2B4O7·10H2O (pH 8.7). Voltammetric data were compared with the results of tin in a phosphate solution of pH 8.7, presented in the previous work, in order to study the influence of these anions on the growth of tin oxides. The thicknesses of grown oxides were determined using ex-situ ellipsometric technique and the volume per charge unity of the film, Vf, was calculated for different charge densities of the film. The results showed that less dense films were obtained at higher sweep rates. Tin oxide films grown in phosphate solution at 2 mV s-1 were denser than those grown in borate solution at the same sweep rate. The kinetic parameters, determined applying the ohmic model, showed that there are no significant differences between the kinetics at the metal/film interface of tin in borate and tin in phosphate solutions. Despite these facts, the ionic specific resistivity for oxide film growth in borate solution were significantly higher than in phosphate solution. This result indicates that incorporation of anions occurs during the growth of the films

Colloidal dendritic nanostructures of gold and silver for SERS analysis of water pollutants

Surface-Enhanced Raman Scattering (SERS) using colloidal metal (Ag, Au) nanoparticles has been regarded as a powerful method for detecting organic pollutants at vestigial levels. Although less investi- gated, the controlled synthesis of binary nanostructures comprising two metals provides an alternative route to SERS platforms with tuned surface plasmon resonances. Here, we demonstrate that the use of dendrimers allows the formation of distinct combinations of Ag:Au nanostructures that are composed of smaller metal nanocrystals. Our research highlights the role of the dendrimer macromolecules as a multipurpose ligand in the generation of such hybrid nanostructure, including as a reducing agent, an effective long-term colloidal stabilizer and as a molecular glue for interconnecting the primary metal nanocrystals. Noteworthy, the dendrimer-based Ag:Au hybrid nanostructures are more SERS sensitive as compared to the corresponding colloidal blends or to the single-phase metals, as revealed by using molecular pesticides as analytes in spiked water samples. We suggest that the high SERS sensitivity of the hybrid nanostructures is due to interparticle plasmonic coupling occurring between the primary metal nanoparticle aggregates, whose arrangement is templated by the presence of the dendrimer macromolecules.publishe

Dendrimer Stabilized Nanoalloys for Ink-Jet Printing of Surface-Enhanced Raman Scattering Substrates

Research on paper substrates prepared by inkjet deposition of metal nanoparticles for sensing applications has become a hot topic in recent years; however, the design of such substrates based on the deposition of alloy nanoparticles remains less explored. Herein, we report for the first time the inkjet printing of dendrimer-stabilized colloidal metal nanoalloys for the preparation of paper substrates for surface-enhanced Raman scattering (SERS) spectroscopy. To this end, nanoassemblies containing variable molar ratios of Au:Ag were prepared in the presence of poly(amidoamine) dendrimer (PAMAM), resulting in plasmonic properties that depend on the chemical composition of the final materials. The dendrimer-stabilized Au:Ag:PAMAM colloids exhibit high colloidal stability, making them suitable for the preparation of inks for long-term use in inkjet printing of paper substrates. Moreover, the pre-treatment of paper with a polystyrene (PS) aqueous emulsion resulted in hydrophobic substrates with improved SERS sensitivity, as illustrated in the analytical detection of tetramethylthiuram disulfide (thiram pesticide) dissolved in aqueous solutions. We suggest that the interactions established between the two polymers (PAMAM and PS) in an interface region over the cellulosic fibres, resulted in more exposed metallic surfaces for the adsorption of the analyte molecules. The resulting hydrophobic substrates show long-term plasmonic stability with high SERS signal retention for at least ninety days.publishe

Medicinal plants with teratogenic potential: current considerations

Este trabalho busca as implicações atuais sobre o uso de plantas medicinais durante a gravidez, alertando sobre aquelas que devem ser evitadas nesse período por serem potencialmente abortivas e/ou teratogênicas. Para tanto, foram realizadas buscas nas bases de dados Sciencedirect, Scielo e Google scholar, adotando-se como critérios de inclusão capítulos de livros e/ou artigos completos (com abstract) e disponíveis, em português, inglês ou espanhol, publicados de 1996 a 2011. Após uma pré-seleção de 83 artigos, 49 bibliografias foram utilizadas na confecção final do artigo, sendo 25 provenientes da base de dados Scielo, 18 do Sciencedirect e 06 do Google scholar. A partir dos artigos estudados, identificaram-se as quatro plantas mais utilizadas como emenagogas/abortivas por pacientes do Serviço de Pré-Natal do SUS: senne, arruda, boldo e buchinha-do-norte ou cabacinha. Assim, é possível concluir que, muitas vezes, a população se utiliza da máxima "se é natural, não faz mal" para fazer uso irracional de produtos naturais, sem a correta orientação, acreditando que esses produtos sejam incapazes de provocar qualquer dano. Esse uso é ainda mais preocupante quando realizado por idosos, gestantes e crianças. Em relação à segurança do uso desses produtos, algumas informações e dados confiáveis ainda são escassos ou contraditórios.The aim of this study was to present the implications of the use of herbs during pregnancy, pointing out those that should be avoided during this condition because of their abortifacient and/or teratogenic potential. We carried out searches in the databases ScienceDirect, Scielo and Google Scholar, adopting as criteria for inclusion: book chapters and/or complete articles (with abstract), available in English, Portuguese or Spanish, published from 1996 to in 2011. After a pre-selection of 83 articles, 49 bibliographies were used in the manufacturing end of the article, where 25 were from the Scielo database, 18 from ScienceDirect and 6 from Google Scholar. From the articles studied, we identified the four most commonly used plants as emmenagogue/abortifacient agents by patients of the Department of Prenatal SUS: senne, arruda, boldo and buchinha-do-norte or cabacinha. Thus, we conclude that people often adhere to the maxim "if it's natural, it does no harm" in their rational use of natural products, without the right guidance, believing that these products are safe to use. This usage is even more worrisome among the elderly, pregnant women and children. Regarding the safety of these products, some information and reliable data are scarce or contradictory

Chemical strategies for dendritic magneto-plasmonic nanostructures applied to surface-enhanced Raman spectroscopy

Chemical analyses in the field using surface-enhanced Raman scattering (SERS) protocols are expected to be part of several analytical procedures applied to water quality monitoring. To date, these endeavors have been supported by developments in SERS substrate nanofabrication, instrumentation portability, and the internet of things. Here, we report distinct chemical strategies for preparing magneto-plasmonic (Fe3 O4  : Au) colloids, which are relevant in the context of trace-level detection of water contaminants due to their inherent multifunctionality. The main objective of this research is to investigate the role of poly(amidoamine) dendrimers (PAMAMs) in the preparation of SERS substrates integrating both functionalities into single nanostructures. Three chemical routes were investigated to design magneto-plasmonic nanostructures that translate into different ways for assessing SERS detection by using distinct interfaces. Hence, a series of magneto-plasmonic colloids have been characterized and then assessed for their SERS activity by using a model pesticide (thiram) dissolved in aqueous samples.publishe

Educação bilíngue para surdos: intersecções conceituais e formativas / Bilingual education for the deaf: conceptual and formative intersections

O estudo objetiva compreender as concepções de educação bilíngue para surdos e suas intersecções para a formação docente. O trabalho foi desenvolvido no Grupo de Estudos e Pesquisas Educação, Docência e Estudos Surdos - GEPEDES no Instituto Federal de Educação, Ciência e Tecnologia-Campus Quixadá. Parte-se da problemática em que se sobressaem no panorama da educação de surdos as abordagens oralistas dominantes em detrimento de perspectivas bilíngues. Além da predominância ouvintista, vislumbra-se também o distanciamento entre a formação de professores e os desafios da prática em sala de aula diante de alunos surdos. Para tanto, recorreu-se à pesquisa qualitativa do tipo estudo de caso, com aplicação de questionário aberto como procedimento de coleta de dados, sob um conjunto de 22 alunos do curso de Licenciatura em Geografia.  Os resultados evidenciam diversas percepções ainda difusas e limitadas sobre educação bilíngue de surdos, restringindo-a a simples comunicação e interação adaptativa à cultura ouvintista. Assim, trata-se de concepções controversas de suposto “ajustamento” inclusivo do surdo à uma sociedade eminentemente ouvinte. Isto traz reflexões sobre o currículo dos cursos de formação docente, aos saberes profissionais necessários e à prática em sala de aula desses futuros professores. Palavras-chave: Educação bilíngue, Formação, Prática.ABSTRACTThe study aims to understand the concepts of bilingual education for the deaf and their intersections for teacher training. The work was developed at the Group of Studies and Research Education, Teaching and Deaf Studies - GEPEDES at the Federal Institute of Education, Science and Technology-Campus Quixadá. It starts with the problem in which the dominant oralist approaches stand out in the panorama of deaf education at the expense of bilingual perspectives. In addition to the predominance of listeners, there is also a gap between the training of teachers and the challenges of classroom practice in the face of deaf students. For that, qualitative research of the case study type was used, with the application of an open questionnaire as a data collection procedure, under a group of 22 students of the Geography Degree course. The results show several still diffuse and limited perceptions about bilingual education for the deaf, restricting it to simple communication and adaptive interaction to the listening culture. Thus, these are controversial conceptions of supposedly “adjusting” inclusive of the deaf to an eminently listening society. This brings reflections on the curriculum of teacher training courses, the necessary professional knowledge and the classroom practice of these future teachers. 

Tolerance and Adaptability of Tomato Genotypes to Saline Irrigation

High salt concentration in irrigation water is often a limiting factor to tomato production in Brazil. However, there is limited information available regarding the tolerance of tomato genotypes to saline irrigation. An experiment was conducted in a protected environment using a randomized block design with four replications. Treatments consisted of 12 tomato genotypes cultivated in an environment with varying levels of salt stress. Moderate and severe salt stress affected plant height, transversal and longitudinal diameter of fruit, fresh mass, yield, and number of tomato fruit per plant. Cluster analysis, stability, and adaptability provided the best estimates to identify the most adaptable genotype to saline stress, with the genotypes Maestrina, Onix, Pizzadoro, and Shanty being the best adapted to moderate and severe saline stress conditions. The genotypes Maestrina, Onix, Pizzadoro, and Shanty were identified as most adaptable to and stable under salt stress. Sodium absorption increased as irrigation salinity increased. In addition, P, K, and Ca concentration decreased under salt stress, which caused damage to all yield components and plant nutrition. The genotype Onix was more tolerant to the effects of moderate saline irrigation, while the genotypes Sheena, Sperare, Santa Clara, IPA 6, and Dominador had lower losses under severe salt stress conditions