Synthesis of precursors of the rare 3-O-methylmannose polysaccharides present in Nontuberculous Mycobacteria

3-O-methylmannose polysaccharides (MMPs) are cytoplasmic carbohydrates synthesized by mycobacteria, which play important intracellular roles, such as for example in metabolism regulation. An important way to confirm if the inhibition of the synthesis of these polysaccharides will critically affect the survival of mycobacteria is the study of the biosynthetic pathways from these molecules on these microorganisms. The purpose of this work is the efficient synthesis of three saccharides, which are rare cellular precursors from the biosynthesis of the mycobacterial polysaccharides, allowing its study. In order to obtain these molecules, a chemical strategy to connect two precursors was used. This process is called chemical glycosylation and its importance will be highlighted as an important alternative to enzymatic glycosylation. The first objective was the synthesis of the disaccharides Methyl (3-O-methyl-α-D-mannopyranosyl)-(1→4)-3-O-methyl-α-D-mannopyranoside and (3-O-Methyl-α-D-mannopyra- nosyl)-(1→4)-3-O-methyl-(α/β)-D-mannopyranose. The mannose precursors were prepared before the glycosylation reaction. The same mannosyl donor was used in the preparation of both molecules and its efficient synthesis was achieved using a 8 step synthetic route from D-mannose. A different mannosyl acceptor was used in the synthesis of each disaccharide and their syntheses were also efficient, the first one a 4 step synthetic route from α-methyl-D-mannose and the second one as an intermediate from the synthesis of the mannosyl donor. The stereoselective preparation of these disaccharides was performed successfully. The second and last objective of the proposed work was the synthesis of the tetrasaccharide methyl (3-O-methyl-α-D-mannopyranosyl-(1→4)-3-O-methyl-α-D-mannopyra- nosyl-(1→4)-3-O-methyl-α-D-mannopyranosyl-(1→4)-3-O-methyl-α-D-mannopyranoside. The disaccharide acceptor and donor to be linked through a stereoselective glycosidic reaction had to be first synthesized. Several synthetic strategies were studied. Neither the precursors nor the tetrasaccharide were synthesized, but a final promising synthetic route for its preparation has been proposed

Analysis of the efficiency of wind turbine gearboxes using the temperature variable

The aim of this paper is to evaluate how lubricant selection affects gearbox efficiency and overall energy production by analysing real data from wind farms, monitored and controlled by a Supervisory Control and Data Acquisition (SCADA system). The turbines analysed worked with two or more oil types for the same amount of hours, which allowed to establish relations between the active power curves and wind velocity; oil temperature inside gearboxes and wind velocity; and oil temperature inside gearboxes and active power production. The results of this study evidenced a direct relation between oil characteristics and energy efficiency i.e. gearboxes working with mineral oil perform better then gearboxes working with synthetic oils. Those differences can be significant in terms of active power production. Also, it was observed oil degradation as function of temperature increase, with changes on viscosity, which reveals that temperature behaviour along the active power curve is strongly related to oil' characteristics. (C) 2018 Elsevier Ltd. All rights reserved.Agência financiadora Portuguese Foundation for Science and Technology (FCT) PTDC/AAG-TEC/1710/2014 MONITOR project - Atlantic Area EAPA_333/2016 Portuguese Foundation for Science and Technology under the Portuguese Researchers' Programme 2014 IF/00286/2014/CP1234 Marie Sklodowska-Curie Actions of the European Union's H2020-MSCA-IF-EF-RI-2016/under REA - 748747info:eu-repo/semantics/publishedVersionhttp://creativecommons.org/licenses/by/4.0

Quantum-enhanced reinforcement learning

Dissertação de mestrado em Engenharia FísicaThe field of Artificial Intelligence has lately witnessed extraordinary results. The ability to design a system capable of beating the world champion of Go, an ancient Chinese game known as the holy grail of AI, caused a spark worldwide, making people believe that some thing revolutionary is about to happen. A different flavor of learning called Reinforcement Learning is at the core of this revolution. In parallel, we are witnessing the emergence of a new field, that of Quantum Machine Learning which has already shown promising results in supervised/unsupervised learning. In this dissertation, we reach for the interplay between Quantum Computing and Reinforcement Learning. This learning by interaction was made possible in the quantum setting using the con cept of oraculization of task environments suggested by Dunjko in 2015. In this dissertation, we extended the oracular instances previously suggested to work in more general stochastic environments. On top of this quantum agent-environment paradigm we developed a novel quantum algorithm for near-optimal decision-making based on the Reinforcement Learn ing paradigm known as Sparse Sampling, obtaining a quantum speedup compared to the classical counterpart. The achievement was a quantum algorithm that exhibits a complexity independent on the number of states of the environment. This independence guarantees its suitability for dealing with large state spaces where planning may be inapplicable. The most important open questions remain whether it is possible to improve the orac ular instances of task environments to deal with even more general environments, especially the ability to represent negative rewards as a natural mechanism for negative feedback instead of some normalization of the reward and the extension of the algorithm to perform an informed tree-based search instead of the uninformed search proposed. Improvements on this result would allow the comparison between the algorithm and more recent classical Reinforcement Learning algorithms.O campo da Inteligência Artificial tem tido resultados extraordinários ultimamente, a capacidade de projetar um sistema capaz de vencer o campeão mundial de Go, um antigo jogo de origem Chinesa, conhecido como o santo graal da IA, causou uma faísca em todo o mundo, fazendo as pessoas acreditarem em que algo revolucionário estar a para acontecer. Um tipo diferente de aprendizagem, chamada Aprendizagem por Reforço está no cerne dessa revolução. Em paralelo surge também um novo campo, o da Aprendizagem Máquina Quântica, que já vem apresentando resultados promissores na aprendizagem supervisionada/não, supervisionada. Nesta dissertação, procuramos invés a interação entre Computação Quântica e a Aprendizagem por Reforço. Esta interação entre agente e Ambiente foi possível no cenário quântico usando o conceito de oraculização de ambientes sugerido por Dunjko em 2015. Neste trabalho, estendemos as instâncias oraculares sugeridas anteriormente para trabalhar em ambientes estocásticos generalizados. Tendo em conta este paradigma quântico agente-ambiente, desenvolvemos um novo algoritmo quântico para tomada de decisão aproximadamente ótima com base no paradigma da Aprendizagem por Reforço conhecido como Amostragem Esparsa, obtendo uma aceleração quântica em comparação com o caso clássico que possibilitou a obtenção de um algoritmo quântico que exibe uma complexidade independente do número de estados do ambiente. Esta independência garante a sua adaptação para ambientes com um grande espaço de estados em que o planeamento pode ser intratável. As questões mais pertinentes que se colocam é se é possível melhorar as instâncias oraculares de ambientes para lidar com ambientes ainda mais gerais, especialmente a capacidade de exprimir recompensas negativas como um mecanismo natural para feedback negativo em vez de alguma normalização da recompensa. Além disso, a extensão do algoritmo para realizar uma procura em árvore informada ao invés da procura não informada proposta. Melhorias neste resultado permitiriam a comparação entre o algoritmo quântico e os algoritmos clássicos mais recentes da Aprendizagem por Reforço

Traceability support in software product lines

Dissertação apresentada na Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa para a obtenção do grau de Mestre em Engenharia Informática.Traceability is becoming a necessary quality of any modern software system. The complexity in modern systems is such that, if we cannot rely on good techniques and tools it becomes an unsustainable burden, where software artifacts can hardly be linked to their initial requirements. Modern software systems are composed by a many artifacts (models, code, etc.). Any change in one of them may have repercussions on many components. The assessment of this impact usually comes at a high cost and is highly error-prone. This complexity inherent to software development increases when it comes to Software Product Line Engineering. Traceability aims to respond to this challenge, by linking all the software artifacts that are used, in order to reason about how they influence each others. We propose to specify, design and implement an extensible Traceability Framework that will allow developers to provide traceability for a product line, or the possibility to extend it for other development scenarios. This MSc thesis work is to develop an extensible framework, using Model-Driven techniques and technologies, to provide traceability support for product lines. We also wish to provide basic and advanced traceability queries, and traceability views designed for the needs of each user

Modulation format comparison in PMD-Impaired 40Gbps systems

Tese de mestrado. Engenharia Electrotécnica e de Computadores. Faculdade de Engenharia. Universidade do Porto. 200

Marine energy prototype testing at Ria Formosa

Economic growth and increasing human demands are among the most important factors for growing world energy consumption. Energy is present in everything around us: it is a property of all objects and is essential to life. We find various forms of energy in the world around us. When plants grow, for example, they are converting sunlight energy into chemical energy in the form of carbohydrates and other compounds stored in your body (e.g. sugars). The form of energy that man uses most today is the chemical energy contained in fossil fuels, such as oil, coal and natural gas. About 80% of the energy we use comes from these sources. However, these sources are very polluting, since their use releases substances harmful to the environment and to public health. An example of this is the increased concentration of greenhouse gases such as carbon dioxide (CO2) in the atmosphere, which is a cause of climate change. In addition to pollutants, these sources of energy are non-renewable, which means that they are being consumed at a faster rate than is necessary for their production, so their availability is decreasing. Due to the increasing oil and natural gas prices, reduced fuel reserves and the requirement for reduced CO2 emissions to avert climate change, the use of alternative energy sources is both financially unavoidable and environmentally preferable (UN, 2015). Hence, generating renewable energy is nowadays one of the most relevant endeavours for research. Countries worldwide now recognise the need to incorporate renewable energy resources in their energy policy as an alternative to finite fossil fuel resources in order to achieve future energy security and to mitigate the effects of climate change induced by human activities. Today, renewable energy is now firmly entrenched as the world's fastest growing energy sector (IEA, 2017).info:eu-repo/semantics/publishedVersio

Avaliação de compostos de Cu(I) como novos agentes quimioterapêuticos

As doenças oncológicas assumem-se como um dos problemas mais graves a nível mundial, representando a segunda maior causa de morte. É esperado que o número de novos casos continue a aumentar devido ao aumento e envelhecimento populacional, pelo que é imprescindível entender melhor os mecanismos subjacentes ao cancro e investir no desenvolvimento de novas terapias, nomeadamente pela procura de novos fármacos que possam substituir os utilizados na quimioterapia atual. Os fármacos utilizados atualmente neste tipo de terapia apresentam alguns problemas como a resistência adquirida pelas células tumorais a estes compostos, e a baixa especificidade para o local do tumor, que resulta em efeitos secundários indesejáveis. Neste trabalho foi estudado o potencial anticancerígeno de novos compostos metálicos de Cu(I) em células tumorais HCT116 (cancro colorretal) através de ensaios de citotoxicidade, bem como os mecanismos de ação subjacentes a estes compostos pela realização de diversos ensaios biológicos. Ficou demonstrado que estes compostos apresentam uma citotoxicidade elevada para células tumorais HCT116, principalmente o composto JL10, não demonstrando toxicidade em células saudáveis, o que pode permitir reduzir os efeitos secundários durante o tratamento. Os valores de IC50 calculados são bastante promissores, sendo menores que os valores dos compostos utilizados atualmente na quimioterapia. Os compostos mostraram a capacidade de despoletar a via intrínseca da apoptose e autofagia, bem como de internalização em células HCT116. O composto JL10 foi também capaz de induzir a produção de ROS em células HCT116, que podem ser responsáveis pela ativação da via intrínseca da apoptose, e demonstrou uma ação citostática ao bloquear o ciclo celular na fase G1. Para além disso, também mostrou capacidade de clivar o pDNA através de mecanismos oxidativos. Pela análise proteómica observou-se a interferência com diversas vias celulares, afetando o folding e síntese de proteínas, e diminuindo a atividade metabólica das células.Oncologic diseases are one of the worst health issues worldwide, representing the second cause of death. It is expected that the number of cases keep increasing due to the populational increase and aging. This makes necessary to better understand the mechanisms leading to these diseases and develop new therapies that replace the drugs used nowadays in chemotherapy. The drugs used nowadays face some challenges like the acquired resistance of the tumoral cells and their low specificity to the tumour leading to unwanted side effects. In this work it was studied the anticarcinogenic potential of the metal compounds of Cu(I) in tumour cells of the cell line HTC116 (colorectal cancer), through assays of cytotoxicity, as well as the mechanisms of action of the compounds through several biological assays. It was demonstrated that these compounds present a high toxicity towards the tumour cells HTC116. Interestingly, the compound JL10 does not show a high toxicity towards healthy cells, which might reduce the side effects during treatment. The calculated IC50 values are quite promising, as they are lower than the ones of the drugs used nowadays in chemotherapy. The compounds show the ability to induce cell death trough apoptosis for the intrinsic pathway and autophagy, as well as internalization in HCT116 cells. The compound JL10 was also able to induce the production of ROS in the cells HTC116, which might be responsible for the activation of the intrinsic pathway of apoptosis, showing also a potential cytostatic, as it blocks the cell cycle in the G1 phase. Besides it also shows the ability to cleave pDNA through oxidative mechanisms. Proteomic analysis showed interference with several cellular pathways, affecting the protein folding and synthesis, diminishing the metabolic activity of the cells

Ventilação natural (estudo de um caso de ventilação natural)

Dissertação apresentada à Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa para obtenção do grau de Mestre em Engenharia MecânicaO presente estudo teve como objectivo analisar a ventilação natural, recorrendo à simulação numérica. Aborda-se o problema da ventilação natural de um edifício em comunicação com o exterior através de duas aberturas de ventilação. Isto é, para a representação numérica do escoamento tridimensional assumiu-se um edifício de forma cúbica 5x5x5 m, em comunicação com o exterior através de duas aberturas de ventilação. Apesar dos escoamentos no interior dos edifícios serem promovidos pela acção conjunta do vento natural e da libertação de calor, para o referido estudo o escoamento só será promovido pela acção do vento natural. Por fim, com os resultados das várias simulações, teve-se como objectivo caracterizar as perdas de carga nas aberturas de ventilação, e nomeadamente, a influência da porosidade na perda de carga

Satisfação organizacional, identificação organizacional e intenção de turnover : estudo comparativo com uma amostra de trabalhadores do sector farmacêutico

Tese de mestrado, Psicologia (Secção de Psicologia dos Recursos Humanos, do Trabalho e das Organizações), Universidade de Lisboa, Faculdade de Psicologia, 2016Para fazer face à crise financeira que o país atravessa e ao aumento da concorrência e da exigência dos clientes, cada vez mais as organizações reconhecem que são os seus colaboradores que podem fazer a diferença. Neste cenário, torna-se importante investir no estudo de variáveis psicológicas, que permitam ampliar o conhecimento sobre o comportamento do indivíduo em contexto organizacional. O presente estudo tem como principal objetivo estudar a satisfação organizacional, a identificação organizacional e a intenção de turnover em trabalhadores do setor farmacêutico, bem como as relações entre estas variáveis. Pretende-se, ainda, comparar os níveis das variáveis referidas, em função da implementação ou não de práticas de recursos humanos. Para a recolha de dados, foram aplicados três instrumentos de medida a uma amostra de 123 colaboradores, os quais foram distribuídos por dois grupos: um, em que todas as práticas de recursos humanos foram implementadas, e outro, em que nem todas estas práticas foram implementadas. Os resultados evidenciam a existência de uma relação direta e significativa entre Satisfação Organizacional e Identificação Organizacional, de uma relação inversa e significativa entre Satisfação Organizacional e Intenção de Turnover, e entre Identificação Organizacional e Intenção de Turnover, e do papel mediador da Satisfação Organizacional na relação entre Identificação Organizacional e Intenção de Turnover. Verifica-se também que, a implementação de práticas de recursos humanos não tem influência significativa na satisfação e identificação organizacionais e na intenção de turnover. No final, são discutidos os principais contributos do estudo e apresentadas algumas limitações e sugestões de investigação.To deal with the financial crisis the country is currently facing and increasing competition and client’s demands, organizations are more and more acknowledging their employees as the ones that can make a difference. In this scenario, it becomes important to invest in studying psychological variables that allow us to expand our knowledge on how individuals behave in organizational contexts. The aim of this research is studying organizational satisfaction, organizational identification and turnover intention in pharmaceutical sector workers, as well as the interactions between those variables. It also intends to compare the levels of the referred variables, based on whether human resources practices were implemented. Regarding the data collection, three measuring instruments were applied to a sample of 123 employees that were separated into two groups: in one of them all the human resources practices were implemented, whilst in the other not all practices were implemented. The results point out a direct significant correlation between Organizational Satisfaction and Organizational Identification, an inverse significant correlation between Organizational Satisfaction and Turnover Intention and also between Organizational Identification and Turnover Intention, in which Organization Satisfaction seems to have a mediating role. The implementation of human resources practices doesn’t have a significant influence in organizational satisfaction and identification and turnover intention. At the end we discuss the main contributions of this study and present some limitations and suggestions for future investigations