Perspectives and approaches for the internet of things

Dissertação para obtenção do Grau de Mestre em Engenharia Electrotécnica e de Computadores

Diving into the depth of primary motor cortex: a high-resolution investigation of the motor system using 7Tesla fMRI

Dissertação para a obtenção do Grau de Mestre em Engenharia Biomédica

Storage of water molecules into biomimetic heterostructures: the role of roughness

The development of devices based on heterostructured thin films of biomolecules conveys a huge contribution on biomedical field. However, to achieve high efficiency of these devices, the storage of water molecules into these heterostructures, in order to maintain the biological molecules hydrated, is mandatory. Such hydrated environment may be achieved with lipids molecules which have the ability to rearrange spontaneously into vesicles creating a stable barrier between two aqueous compartments. Yet it is necessary to find conditions that lead to the immobilization of whole vesicles on the heterostructures. In this work, the conditions that govern the deposition of open and closed liposomes of 1.2-dipalmitoyl-sn-Glycero-3-[Phospho-rac-(1-glycerol)] (sodium Salt) (DPPG) onto polyelectrolytes cushions prepared by the layer-by-layer (LbL) method were analyzed. Electronic transitions of DPPG molecules as well as absorption coefficients were obtained by vacuum ultraviolet spectroscopy, while the elemental composition of the heterostructures was characterized by x-ray photoelectron spectroscopy (XPS). The presence of water molecules in the films was inferred by XPS and infrared spectroscopy. Quartz crystal microbalance (QCM) data analysis allowed to conclude that, in certain cases, the DPPG adsorbed amount is dependent of the bilayers number already adsorbed. Moreover, the adsorption kinetics curves of both adsorbed amount and surface roughness allowed to determine the kinetics parameters that are related with adsorption processes namely, electrostatic forces, liposomes diffusion and lipids re-organization on surface. Scaling exponents attained from atomic force microscopy images statistical analysis demonstrate that DPPG vesicles adsorption mechanism is ruled by the diffusion Villain model confirming that adsorption is governed by electrostatic forces. The power spectral density treatment enabled a thorough description of the accessible surface of the samples as well as of its inner structural properties. These outcomes proved that surface roughness influences the adsorption of DPPG liposomes onto surfaces covered by a polyelectrolyte layer. Thus, low roughness was shown to induce liposome rupture creating a lipid bilayer while high roughness allows the adsorption of whole liposomes. In addition, the fraction of open liposomes calculated from the normalized maximum adsorbed amounts decreases with the cushion roughness increase, allowing us to conclude that the surface roughness is a crucial variable that governs the adsorption of open or whole liposomes. This conclusion is fundamental for the development of well-designed sensors based on functional biomolecules incorporated in liposomes. Indeed, LbL films composed of polyelectrolytes and liposomes with and without melanin encapsulated were successfully applied to sensors of olive oil.

Unravelling the role of alpha 2,6 sialic acid on mouse dentritic cells functions

RESUMO: As células dendríticas (CDs) são fundamentais na imunomodulação e iniciação de respostas imunes adaptativas, enquanto os ácidos siálicos (Sias) são potenciais imunomoduladores. Estas células expressam níveis elevados da sialiltransferase ST6Gal-1, que transfere Sias para a posição terminal de oligossacáridos. De facto, a maturação de CDs está associada a uma diminuição da sialilação na sua superfície celular. Apesar de ter função biológica desconhecida, a forma solúvel, extracelular de ST6Gal-1 aumenta em cancros e inflamação. Ainda assim, esta foi recentemente identificada como moduladora da hematopoiese. Considerando o importante papel das CDs na iniciação de respostas anticancerígenas, uma ligação entre a sialilação extrínseca induzida por ST6Gal-1 extracelular e o seu papel na modulação de CDs deve ser identificada. Neste trabalho hipotetizou-se que a sialilação α2,6 extrínseca de CDs diminui o seu perfil de maturação mediante ativação por lipopolissacarídeo (LPS). O objetivo principal foi sialilar extrinsecamente em α2,6 CDs da medula óssea de murganhos, avaliando os seus perfis de maturação e de libertação de citocinas, após estimulação com LPS (por Citometria de Fluxo e ELISA, respetivamente). Ao contrário da hipótese, o perfil celular não foi modulado, usando várias abordagens. Por outro lado, a consequência da falta de α2,6 Sias na maturação de CDs foi avaliada analisando: 1) CDs da medula óssea de murganhos tratadas com sialidase, 2) CDs da medula óssea e 3) CDs das vias aéreas, ambas de murganhos deficientes em ST6Gal-1, comparando com a estirpe selvagem. Estes resultados sugerem que a perta total de α2,6 Sias se relaciona com o aumento da expressão do complexo de histocompatibilidade principal de classe II. Apesar de controverso, é provável existirem mecanismos inerentes à ativação por LPS, reduzindo a eficácia de ST6Gal-1 extracelular. Por outro lado, a modificação no perfil de CDs de murganhos deficientes em ST6Gal-1 poderá relacionar-se com uma predisposição para um estado inflamatório severo. Com isto, o trabalho desenvolvido abriu futuras linhas de investigação, nomeadamente explorar outros fatores envolvidos na (de)sialilação α2,6 de CDs, podendo ter impacto em imunoterapia com uso de CDs.--------------------------ABSTRACT: Dendritic cells (DCs) are vital for immunomodulation and the initiation of adaptive immune responses, whereas sialic acids (Sias) are potential immunomodulators. These cells express high levels of sialyltransferase ST6Gal-1, responsible for transferring Sias to the terminal position of oligosaccharide chains. Indeed, DCs’ maturation is associated with decreased cell surface sialylation. Although its biological significance is unknown, the soluble, extracellular form of ST6Gal-1 increases in cancers and inflammation. However, extracellular ST6Gal-1 was recently identified as modulator of hematopoiesis. Considering that DCs play a crucial role in the initiation of a productive anti-cancer immune response, a link between extrinsic sialylation by the extracellular ST6Gal-1 on DC function needs to be investigated. We hypothesize that extrinsic α2,6 sialylation of DCs diminishes their maturation features upon lipopolysaccharide (LPS) stimulation. The main goal was to extrinsically α2,6 sialylate mice bone marrow derived DCs (BMDCs) and to evaluate their maturation and cytokine profiles upon LPS stimulation (by Flow Cytometry and ELISA, respectively). Unlike the hypothesis, we observed that BMDCs’ profile is not modulated, even using several approaches. In contrast, the consequence of lacking cell surface α2,6 Sias in DC maturation was assessed by analysing: 1) sialidase treated BMDCs, 2) BMDCs from mice lacking ST6Gal-1 and 3) DCs from mice airways, comparing wild type with ST6Gal-1 knockout mice. These results suggest that overall lack in α2,6 Sias is related with increased expression of major histocompatibility class II (MHC-II). Although appearing to be controversial findings, other intracellular mechanisms might be occurring upon LPS-induced BMDC activation, probably reducing extracellular ST6Gal-1 effect. In opposite, the modification observed in DC profile of ST6Gal-1 knockout mice might be related to its predisposition to a more severe inflammatory status. With this, the developed work opened future lines of investigation, namely exploring other factors involved in α2,6 (de)sialylation of DC, which might have influence in immunotherapy using DCs.

The efficacy of the old way/new way methodology on the correction of an automated technical error and its impact on the athlete’s psychological skills : Case study in tennis

The aim of this study was to evaluated the efficacy of the Old Way/New Way methodology (Lyndon, 1989/2000) with regard to the permanent correction of a consolidated and automated technical error experienced by a tennis athlete (who is 18 years old and has been engaged in practice mode for about 6 years) in the execution of serves. Additionally, the study assessed the impact of intervention on the athlete’s psychological skills. An individualized intervention was designed using strategies that aimed to produce a) a detailed analysis of the error using video images; b) an increased kinaesthetic awareness; c) a reactivation of memory error; d) the discrimination and generalization of the correct motor action. The athlete’s psychological skills were measured with a Portuguese version of the Psychological Skills Inventory for Sports (Cruz & Viana, 1993). After the intervention, the technical error was corrected with great efficacy and an increase in the athlete’s psychological skills was verified. This study demonstrates the methodology’s efficacy, which is consistent with the effects of this type of intervention in different contexts.

Psychological safety, authentic leadership and social networks : A psycho-structural approach to the study of groups

Tese de Doutoramento em Psicologia na área de especialização de Psicologia das Organizações apresentada ao ISPA - Instituto Universitário

Exploring the relationship between toxin and spore production in the human enteric pathogen Clostridium difficile

RESUMO: Clostridium difficile é presentemente a principal causa de doença gastrointestinal associada à utilização de antibióticos em adultos. C. difficile é uma bactéria Gram-positiva, obrigatoriamente anaeróbica, capaz de formar endósporos. Tem-se verificado um aumento dos casos de doença associada a C. difficile com sintomas mais severos, elevadas taxas de morbilidade, mortalidade e recorrência, em parte, devido à emergência de estirpes mais virulentas, mas também devido à má gestão do uso de antibióticos. C. difficile produz duas toxinas, TcdA e TcdB, que são os principais fatores de virulência e responsáveis pelos sintomas da doença. Estas são codificadas a partir do Locus de Patogenicidade (PaLoc) que codifica ainda para um regulador positivo, TcdR, uma holina, TcdE, e um regulador negativo, TcdC. Os esporos resistentes ao oxigénio são essenciais para a transmissão do organismo e recorrência da doença. A expressão dos genes do PaLoc ocorre em células vegetativas, no final da fase de crescimento exponencial, e em células em esporulação. Neste trabalho construímos dois mutantes de eliminação em fase dos genes tcdR e tcdE. Mostrámos que a auto-regulação do gene tcdR não é significativa. No entanto, tcdR é sempre necessário para a expressão dos genes presentes no PaLoc. Trabalho anterior mostrou que, com a exceção de tcdC, os demais genes do PaLoc são expressos no pré-esporo. Mostrámos aqui que TcdA é detectada à superfície do esporo maduro e que a eliminação do tcdE não influencia a acumulação de TcdA no meio de cultura ou em associação às células ou ao esporo. Estas observações têm consequências para o nosso entendimento do processo infecioso: sugeremque o esporo possa ser também um veículo para a entrega da toxina nos estágios iniciais da infecção, que TcdA possa ser libertada durante a germinação do esporo, e que o esporo possa utilizar o mesmo receptor reconhecido por TcdA para a ligação à mucosa do cólon.---------------------------ABSTRACT: Clostridium difficile is currently the major cause of antibiotic-associated gastrointestinal diseases in adults. This is a Gram-positive bacterium, endospore-forming and an obligate anaerobe that colonizes the gastrointestinal tract. Recent years have seen a rise in C. difficile associated disease (CDAD) cases, associated with more severe disease symptoms, higher rates of morbidity, mortality and recurrence, which were mostly caused due to the emergence of “hypervirulent” strains but also due to changing patterns of antibiotics use. C. difficile produces two potent toxins, TcdA and TcdB, which are the main virulence factors and the responsible for the disease symptoms. These are codified from a Pathogenicity Locus (PaLoc), composed also by the positive regulator, TcdR, the holin-like protein, TcdE, and a negative regulator, TcdC. Besides the toxins, the oxygen-resistant spores are also essential for transmission of the organism through diarrhea; moreover, spores can accumulate in the environment or in the host, which will cause disease recurrence. The expression of the PaLoc genes occurs in vegetative cells, at the end of the exponential growth phase, and in sporulating cells. In this work, we constructed two in-frame deletion mutants of tcdR and tcdE. We showed that the positive auto regulation of tcdR is not significant. However, tcdR is always necessary for the expression of the PaLoc genes. A previous work showed that, except tcdC, all the PaLoc genes are expressed in the forespore. Here, we detected TcdA at the spore surface. Furthermore, we showed that the in-frame deletion of tcdE does not affect the accumulation of TcdA in the culture medium or in association with cells or spores. This data was important for us to conclude about the infeccious process: it suggests that the spore may be the vehicle for the delivery of TcdA in early stages of infection, that TcdA may be released during spores germination and that this spore may use the same receptor recognized by TcdA to bind to the colonic mucosa.

Exploring the consumer decision journey and online shoping experience through an emotional prespective

Traditional consumer decision-making models have long used quantitative research to address a link between emotional and rational behavior. However, little qualitative research has been conducted in the area of online shopping as an end-to-end experience. This study aims to provide a detailed phenomenological account of consumers’ online shopping experience and extend Mckinsey & Companys’s consumer decision journey model from an emotional perspective. Six semi-structured interviews and a focus group of nine people are analyzed using Interpretive Phenomenology Analysis and five superordinate themes emerged from the results: emotional experience, empathy and encouragement, in relation to brand preference, emotional encounters in relation to consumer satisfaction and emotional exchange and relationship with a company or brand. A model interrelating these themes is then introduced to visually represent the emotional essence of a large online purchase. This study promises to be applicable as a descriptive, and perhaps, better predictive report for understanding the complex consumer decision-making process as it relates to online consumer behavior. Future research topics are also identified.

Comparison of different numerical methods for the solution of the time-fractional reaction-diffusion equation with variable diffusion coefficient

In this work we perform a comparison of two different numerical schemes for the solution of the time-fractional diffusion equation with variable diffusion coefficient and a nonlinear source term. The two methods are the implicit numerical scheme presented in [M.L. Morgado, M. Rebelo, Numerical approximation of distributed order reaction- diffusion equations, Journal of Computational and Applied Mathematics 275 (2015) 216-227] that is adapted to our type of equation, and a colocation method where Chebyshev polynomials are used to reduce the fractional differential equation to a system of ordinary differential equations

Systematics, functional morphology and distribution of a bivalve (Apachecorbula muriatica gen. et sp. nov.) from the rim of the ‘Valdivia Deep’ brine pool in the Red Sea

The deep brine pools of the Red Sea comprise extreme, inhospitable habitats yet house microbial communities that potentially may fuel adjacent fauna. We here describe a novel bivalve from a deep-sea (1525 m) brine pool in the Red Sea, where conditions of high salinity, lowered pH, partial anoxia and high temperatures are prevalent. Remotely operated vehicle (ROV) footage showed that the bivalves were present in a narrow (20 cm) band along the rim of the brine pool, suggesting that it is not only tolerant of such extreme conditions but is also limited to them. The bivalve is a member of the Corbulidae and named Apachecorbula muriatica gen. et sp. nov. The shell is atypical of the family in being modioliform and thin. The semi-infaunal habit is seen in ROV images and reflected in the anatomy by the lack of siphons. The ctenidia are large and typical of a suspension feeding bivalve, but the absence of guard cilia and the greatly reduced labial palps suggest that it is non-selective as a response to low food availability. It is proposed that the low body mass observed is a consequence of the extreme habitat and low food availability. It is postulated that the observed morphology of Apachecorbula is a result of paedomorphosis driven by the effects of the extreme environment on growth but is in part mitigated by the absence of high predation pressures.

Development of a thermoelectric generator for the exhaust of a vehicle

Dissertação de mestrado integrado em Engenharia Mecânica

Estimating the colors of paintings

Observers can adjust the spectrum of illumination on paintings for optimal viewing experience. But can they adjust the colors of paintings for the best visual impression? In an experiment carried out on a calibrated color moni- tor images of four abstract paintings obtained from hyperspectral data were shown to observers that were unfamiliar with the paintings. The color volume of the images could be manipulated by rotating the volume around the axis through the average (a*, b*) point for each painting in CIELAB color space. The task of the observers was to adjust the angle of rotation to produce the best subjective impression from the paintings. It was found that the distribution of angles selected for data pooled across paintings and observers could be de- scribed by a Gaussian function centered at 10o, i.e. very close to the original colors of the paintings. This result suggest that painters are able to predict well what compositions of colors observers prefer.

A novel hanging spherical drop system for the generation of cellular spheroids and high throughput combinatorial drug screening

We propose a novel hanging spherical drop system for anchoring arrays of droplets of cell suspension based on the use of biomimetic superhydrophobic flat substrates, with controlled positional adhesion and minimum contact with a solid substrate. By facing down the platform, it was possible to generate independent spheroid bodies in a high throughput manner, in order to mimic in vivo tumour models on the lab-on-chip scale. To validate this system for drug screening purposes, the toxicity of the anti-cancer drug doxorubicin in cell spheroids was tested and compared to cells in 2D culture. The advantages presented by this platform, such as feasibility of the system and the ability to control the size uniformity of the spheroid, emphasize its potential to be used as a new low cost toolbox for high-throughput drug screening and in cell or tissue engineering.

Enalapril alters the formation of the collagen matrix in spontaneously hypertensive rats

OBJECTIVE: To assess the effect of the inhibition of the angiotensin-converting enzyme on the collagen matrix (CM) of the heart of newborn spontaneously hypertensive rats (SHR) during embryonic development. METHODS: The study comprised the 2 following groups of SHR (n=5 each): treated group - rats conceived from SHR females treated with enalapril maleate (15 mg. kg-1.day-1) during gestation; and nontreated group - offspring of nontreated females. The newborns were euthanized within the first 24 hours after birth and their hearts were removed and processed for histological study. Three fields per animal were considered for computer-assisted digital analysis and determination of the volume densities (Vv) of the nuclei and CM. The images were segmented with the aid of Image Pro Plus® 4.5.029 software (Media Cybernetics). RESULTS: No difference was observed between the treated and nontreated groups in regard to body mass, cardiac mass, and the relation between cardiac and body mass. A significant reduction in the Vv[matrix] and a concomitant increase in the Vv[nuclei] were observed in the treated group as compared with those in the nontreated group. CONCLUSION: The treatment with enalapril of hypertensive rats during pregnancy alters the collagen content and structure of the myocardium of newborns.

Development of a semi-automatic self learning pattern recognition system for the control of electronic boards

This project was funded under the Applied Research Grants Scheme administered by Enterprise Ireland. The project was a partnership between Galway - Mayo Institute of Technology and an industrial company, Tyco/Mallinckrodt Galway. The project aimed to develop a semi - automatic, self - learning pattern recognition system capable of detecting defects on the printed circuits boards such as component vacancy, component misalignment, component orientation, component error, and component weld. The research was conducted in three directions: image acquisition, image filtering/recognition and software development. Image acquisition studied the process of forming and digitizing images and some fundamental aspects regarding the human visual perception. The importance of choosing the right camera and illumination system for a certain type of problem has been highlighted. Probably the most important step towards image recognition is image filtering, The filters are used to correct and enhance images in order to prepare them for recognition. Convolution, histogram equalisation, filters based on Boolean mathematics, noise reduction, edge detection, geometrical filters, cross-correlation filters and image compression are some examples of the filters that have been studied and successfully implemented in the software application. The software application developed during the research is customized in order to meet the requirements of the industrial partner. The application is able to analyze pictures, perform the filtering, build libraries, process images and generate log files. It incorporates most of the filters studied and together with the illumination system and the camera it provides a fully integrated framework able to analyze defects on printed circuit boards.