Aprendizagem da usabilidade e prototipagem e a sua aplicação no desenho de um museu virtual

Relatório da Prática de Ensino Supervisionada, Mestrado em Ensino de Informática, Universidade de Lisboa, 2014O presente relatório descreve a prática de intervenção supervisionada levada a cabo no ano letivo 2013/2014, numa turma do 12º ano do Curso Profissional Técnico de Informática de Gestão da Escola Secundária de Camões, que teve como propósito o desenvolvimento do projeto “Museu Virtual Camões” através da criação de um Website. O desenho deste Website teve como objetivo armazenar, gerir e divulgar o espólio do Museu da Escola Secundária de Camões. O projeto relativo à presente intervenção de prática de ensino supervisionada foi realizado no âmbito da disciplina de Sistemas de Informação, em particular no módulo oito “Projeto”. Pretendeu-se criar um conjunto de atividades que consistiram na avaliação, do ponto de vista da usabilidade, de três protótipos para a criação do Website do Museu Virtual. Os objetivos pedagógicos enunciados foram i) saber se com a realização dos testes de usabilidade a protótipos os alunos, no papel de utilizadores, seriam capazes de realizar as tarefas propostas, ii) compreender se a informação relevante era encontrada, o tempo que requeriam as tarefas, e ainda iii) saber se os caminhos tomados se apresentavam mais eficientes, se os utilizadores sabiam o que estavam a fazer e que problemas encontraram. A estratégia de ensino seguida foi a aprendizagem baseada em projetos: modelo que possibilita a organização do processo ensino e aprendizagem que promova e estimule o trabalho autónomo por parte dos alunos, tendo como meta a compreensão dos conceitos e princípios da disciplina, possibilitando a construção do próprio saber e que culmina obrigatoriamente no desenvolvimento de produtos concretos. A avaliação desenvolvida materializou-se com a realização de atividades concretas com propósito formativo através da observação e acompanhamento tanto do desempenho individual dos alunos, como dos grupos de trabalho. E de atividade com propósito sumativo em particular a avaliação dos produtos desenvolvidos. Os resultados mostram que os objetivos de aprendizagem foram satisfatoriamente atingidos. Os alunos desenvolveram competências de utilização de aplicações de prototipagem, adquiriram conhecimentos em aplicações e em avaliação de testes de usabilidade.This report describes the practice of supervised intervention carried out during the school year of 2013/2014, in a 12th grade class of the Technical Vocational Course in Computer Management, at Camões Secondary School. The intervention’s aim was to develop the project "Camões Virtual Museum" through the creation of a website to store, manage and disseminate the estate of the Camões Secondary School Museum. The following supervised teaching experience took place in the Information Systems subject, particularly in module eight, "Project". The goal was to develop a set of activities to evaluate if the three prototypes for the creation of the Virtual Museum website were user-friendly. The stated pedagogical objectives were i) find out if, through the usability tests, the students, in the role of users, would be able to do what they had been asked ii) check if the relevant information was found, note down the time required for completing the tasks and also iii) whether the chosen paths were more efficient, whether the users knew what they were doing and what problems they had found. The adopted teaching strategy was the learning through project work methodology, which allows the organization of the teaching and learning process, while also encouraging students to do independent work. The final aim is for the students to understand the concepts and principles of the subject they are studying, by building their own knowledge and developing specific products. Regarding evaluation, it focused on specific activities, developed with a formative purpose, ran through the observation and monitoring of both the individual performance of students and of the groups. The summative assessment was also used, mainly to evaluate the products developed. The results show that the learning objectives were satisfactorily achieved. The students developed skills to use prototyping applications, and gained expertise in applications and in evaluation of usability tests

Diabetic Cardiomyopathy: Focus on Oxidative Stress, Mitochondrial Dysfunction and Inflammation

Diabetic cardiomyopathy (DCM) is an independent clinical entity defined as structural and functional changes in the myocardium because of metabolic and cellular abnormalities induced by diabetes, resulting in cardiac failure. Hyperglycemia has been seen as a major cause of DCM due to activation of different mechanisms leading to oxidative stress. Several body of evidence show that distinct pathways of oxygen and nitrogen reactive species formation contribute to myocardial impairment. Abnormal mitochondrial morphology and energetics, evoked by abnormal Ca2+ handling, metabolic changes and oxidative stress, are observed in DCM, suggesting a pivotal role of mitochondrial dynamics in disease pathogenesis. In addition, insulin resistance compromises myocardial glucose uptake due to cellular depletion of glucose transporter proteins, together with increased myocardial uptake of free fatty acids and augmented triglyceride levels, which cause cardiomyocyte lipotoxicity. Finally, the state of chronic low-grade inflammation, a feature of obese type 2 diabetes, seems to also play a major role in DCM progression, whose mechanisms have been progressively disclosed. In this book chapter, we review the cellular mechanism contributing to DCM development, focusing on oxidative stress, mitochondrial dysfunction and inflammation of cardiomyocytes, as well as on possible therapeutic strategies

Role of mitochondrial dysfunction in combined bile acid-induced cytotoxicity: the switch between apoptosis and necrosis

The goal of this investigation was to determine whether chenodeoxycholic acid (CDCA)-induced apoptosis is prevented by ursodeoxycholic acid (UDCA) or tauroursodeoxycholic acid (TUDC) and to characterize the involvement of mitochondria in the process. Cultured human HepG2 cells were treated in a dose- and time-dependent protocol in order to establish a sufficiently low exposure to CDCA that causes apoptosis but not necrosis. Low-dose CDCA induced an S-phase block and G2 arrest of the cell cycle, as determined by flow cytometry. As a result, cell proliferation was inhibited. CDCA-induced apoptosis, as determined by fluorescence microscopy of Hoechst 33342-stained nuclei, was evident upon coincubation with TUDC. Additionally, after exposure to UDCA plus CDCA, the cell membrane was permeable to fluorescent dyes. Caspase-9-like activity, poly(ADP-ribose) polymerase (PARP) cleavage, and extensive DNA fragmentation were detected in CDCA-exposed cells and in cells coincubated with TUDC, but not UDCA. CDCA caused a decrease in mitochondrial membrane potential and depletion of ATP, both of which were potentiated by UDCA but not TUDC. The results suggest that UDCA potentiates CDCA cytotoxicity, probably at the level of induction of the mitochondrial permeability transition (MPT). Consequently, as suggested by the lack of the main hallmarks of the apoptotic pathway, in the presence of UDCA, CDCA-induced apoptosis is not properly executed but degenerates into necrosis

Decreased Susceptibility of Heart Mitochondria from Diabetic GK Rats to Mitochondrial Permeability Transition Induced by Calcium Phosphate

Type 2 diabetes (or non-insulin dependent diabetes mellitus, NIDDM) is a common metabolic disease in man. The Goto–Kakizaki (GK) rat has been designed as a NIDDM model. Previous studies with this strain have shown differences at the mitochondrial level. The mitochondrial permeability transition (MPT) is a widely studied phenomenon but yet poorly understood, that leads to mitochondrial dysfunction and cell death. The aim of this work was to compare the differences in susceptibility of induction of the MPT with calcium phosphate in GK and Wistar rats. Our results show that heart mitochondria from GK rats are less susceptible to the induction of MPT, and show a larger calcium accumulation before the overall loss of mitochondrial impermeability

X-ray diffraction and Raman study of nanogranular BaTiO3-CoFe2O4thin films deposited by laser ablation on Si/Pt substrates

Nanocomposite thin films composed by (BaTiO3)1-x-(CoFe2O4)x with different cobalt ferrite concentrations (x) have been deposited by pulsed laser ablation on platinum covered Si(001) substrates. The films structure was studied by X-ray diffraction and Raman spectroscopy. It was found that the CoFe2O4 phase unit cell was compressed along the growth direction of the films, and it relaxed with increasing x. The opposite behavior was observed in the BaTiO3 phase where the lattice parameters obtained from the X-ray measurements presented a progressive distortion of its unit cell with increasing x. The presence of the strain in the films induced a blueshift of the Raman peaks of CoFe2O4 that decreased with increasing CoFe2O4 concentration. Cation disorder in the cobalt ferrite was observed for lower x, where the nanograins are more isolated and subjected to more strain, which was progressively decreased for higher CoFe2O4 content in the films.This work has been financially supported by the Portuguese Foundation for Science and Technology (FCT), through the project POCI/CTM/60181/2004 and the Bilateral Research Action nºB48-06 between CRUP (Portugal) and British Council (UK)

Impact of Carvedilol on the Mitochondrial Damage Induced by Hypoxanthine and Xantine Oxidase - What Role in Myocardial Ischemia and Reperfusion?

Objectivo: Os efeitos cardioprotectores do carvedilol (CV) poderão ser explicados, em parte, por interacções ao nível da mitocôndria cardíaca. O objectivo deste trabalho visou o estudo do efeito protector do CV em mitocôndrias cardíacas durante danos oxidativos induzidos por hipoxantina e xantina oxidase (HX/XO), uma conhecida fonte de estresse oxidativo no sistema cardiovascular. Métodos: As mitocôndrias foram isoladas a partir de corações de ratos Wistar (n=8) e incubadas com o par HX/XO, na presença e na ausência de cálcio. Vários métodos foram utilizados de modo a verificar a acção protectora do CV: avaliação das alterações de volume mitocondrial (variação da densidade óptica da suspensão mitocondrial), tomada e libertação de cálcio mitocondrial (com uma sonda fluorescente, Calcium Green-5N) e respiração mitocondrial (com um eléctrodo de oxigénio). Resultados: O CV reduziu os danos mitocondriais associados à produção de espécies reactivas de oxigénio (ERO) pelos prooxidantes, como verificado pela redução no entumescimento mitocondrial e aumento da capacidade de retenção do cálcio pela mitocôndria. O CV melhorou ainda a capacidade respiratória mitocondrial associada ao estado fosforilativo e aumentou o índice de controlo respiratório (p<0.05) e o quociente ADP/O (p<0.001) das mitocôndrias cardíacas sob estresse oxidativo induzido por HX/XO. Conclusões: Os dados indicam que o CV protegeu parcialmente a mitocôndria cardíaca de danos oxidativos induzidos por HX/XO, o que poderá ser de grande utilidade em situações de isquémiareperfusão do miocárdio. Os resultados também sugerem que a mitocôndria poderá ser um alvo prioritário para a acção benéfica de alguns fármacos cardioprotectores.Objectives: The cardioprotective effects of carvedilol (CV) may be explained in part by interactions with heart mitochondria. The objective of this work was to study the protection afforded by CV against oxidative stress induced in isolated heart mitochondria by hypoxanthine and xanthine oxidase (HX/XO), a well-known source of reactive oxygen species (ROS) in the cardiovascular system. Methods: Mitochondria were isolated from Wistar rat hearts (n=8) and incubated with HX/XO in the presence and in the absence of calcium. Several methods were used to assess the protection afforded by CV: evaluation of mitochondrial volume changes (by measuring changes in the optical density of the mitochondrial suspension), calcium uptake and release (with a fluorescent probe, Calcium Green 5-N) and mitochondrial respiration (with a Clark-type oxygen electrode). Results: CV decreased mitochondrial damage associated with ROS production by HX and XO, as verified by the reduction of mitochondrial swelling and increase in mitochondrial calcium uptake. In the presence of HX and XO, CV also ameliorated mitochondrial respiration in the active phosphorylation state and prevented decrease in the respiratory control ratio (p<0.05) and in mitochondrial phosphorylative efficiency (p<0.001). Conclusions: The data indicate that CV partly protected heart mitochondria from oxidative damage induced by HX and XO, which may be useful during myocardial ischemia and reperfusion. It is also suggested that mitochondria may be a priority target for the protective action of some compounds

The influence of dietary conditions in the effects of resveratrol on hepatic steatosis

Non-alcoholic fatty liver disease (NAFLD) is considered the major cause for the development of chronic liver alterations. Hepatic steatosis is the most benign and common form of NAFLD, although its potential to evolve into more detrimental liver alterations makes its treatment necessary. In this regard, much attention has been paid to polyphenols, with resveratrol being one of the most studied ones. This review is aimed at studying the effects induced by resveratrol on hepatic steatosis in both preclinical studies conducted under different feeding conditions (overfeeding, normal feeding and caloric restriction), and in clinical trials. The vast majority of studies have been conducted by administering the polyphenol at the same time as an obesogenic diet. Under these experimental conditions, resveratrol has shown effectiveness improving diet-induced excessive liver lipid accumulation. Data are scarce for studies carried out by administering resveratrol under standard or energy-restricted feeding conditions. In this regard, while resveratrol retains its effectiveness, ameliorating hepatic steatosis under standard feeding conditions, such an effect has not been reported for the administration of the polyphenol under energy restriction. With regard to clinical trials, in the majority of them, resveratrol did not show its effectiveness in improving hepatic steatosis. This lack of effect could be due to significant differences in the experimental procedures (mainly the length of the experimental period). The relevance of liver fat content at the baseline should also be considered. Altogether, there is no sufficient scientific support so far for proposing resveratrol as a tool for hepatic steatosis treatment.This study has been supported by grants from Ministerio de Economia y Competitividad-Fondo Europeo de Desarrollo Regional, under grant AGL-2015-65719-R MINECO/FEDER, (UE), Instituto de Salud Carlos III (CIBERobn) under Grant CB12/03/30007 and University of the Basque Country, under Grant GIU18-173

Nanogranular BaTiO3–CoFe2O4 thin films deposited by pulsed laser ablation

Detailed structural and magnetic measurements were performed on nanostructured composite thin films of cobalt ferrite (CoFe2O4 - magnetostrictive) dispersed in a barium titanate (BaTiO3 - piezoelectric) matrix, with different CoFe2O4 concentrations (ranging from x=20% to x=70%). The films were deposited by laser ablation on platinum covered Si(100). Their structure was studied by X-ray diffraction and Raman spectroscopy. The magnetic properties were measured with a SQUID magnetometer. The nanocomposite films were polycrystalline and composed by a mixture of tetragonal-BaTiO3 and CoFe2O4 with the cubic spinel structure. The lattice parameter of the CoFe2O4 phase varied from 8.26Å (x=20%) to 8.35Å (x=70%), and, comparing with bulk CoFe2O4, it was under compressive stress that relaxed as its concentration progressively increased. In the tetragonal-BaTiO3 phase, the lattice parameter a was contracted relative to the bulk phase and decreases with x. The lattice parameter c increased from 4.088 Å (x=20%) to 4.376 Å (x=70%), so that the BaTiO3 c axes was increasingly expanded as the quantity of the barium titanate phase was reduced. This behavior was the opposite of that observed in CoFe2O4. The magnetic measurements showed that the coercive fields decreased from 6.6 kOe (x=20%) to 2.3 kOe (x=70%) which was attributed to the progressive relaxation of the stress in the films as well as to the increase of particle agglomeration in bigger polycrystalline clusters with increasing cobalt ferrite concentration. For higher temperatures T=300 K the reduction of magnetocrystalline anisotropy induced a strong reduction of the coercive field.This work has been financially supported by the Portuguese Foundation for Science and Technology (FCT), through the project POCI/CTM/60181/2004

Carvedilol: Relation Between Antioxidant Activity and Inhibition of the Mitochondrial Permeability Transition

Objectivos: A transição de permeabilidade mitocondrial (TPM) é um evento associado a estresse oxidativo severo (por exemplo, durante isquémia e reperfusão do miocárdio) e acumulação excessiva de cálcio mitocondrial, podendo mesmo levar a morte celular. Neste estudo comparou-se o efeito do Carvedilol (CV) na TPM cardíaca induzida por cálcio/fosfato (Ca/Pi) e cálcio/carboxiatractilato (Ca/Catr). Para a indução da TPM por Ca/Pi, o estresse oxidativo tem um papel importante, levando a oxidação de grupos tiólicos proteicos mitocondriais, em contraste com o efeito do Ca/Catr, onde essa oxidação é secundária à indução da TPM e não é motivada por estresse oxidativo. Materiais e métodos: As mitocôndrias foram isoladas a partir do coração de rato e avaliaram-se parâmetros relacionados com a indução da TPM (n=5 para cada indutor): entumescimento mitocondrial e oxidação dos grupos tiólicos proteicos (ambos por espectrofotometria). Resultados: Com Ca/Pi, o CV protegeu a mitocôndria da indução da TPM, nomeadamente na sua forma deletéria de alta condutância. Este efeito evidenciou-se pela diminuição do entumescimento mitocondrial. Este efeito foi simultâneo com a inibição da oxidação dos grupos tiólicos proteicos carmitocondriais (p<0.001). O CV não mostrou efeitos protectores com Ca/Catr. Conclusões: O CV protegeu a mitocôndria cardíaca da TPM, mas apenas quando a oxidação dos grupos tiólicos proteicos foi causa e não consequência da TPM. Estes resultados mostram claramente que, durante agressões ao miocárdio (durante a isquémia/reperfusão, por exemplo), o efeito protector do CV é primariamente devido a um efeito antioxidante, inibindo a produção e os efeitos das espécies reactivas de oxigénio.Objectives: The mitochondrial permeability transition (MPT) is an event related to severe oxidative stress (for example, during myocardial ischemia and reperfusion) and excessive mitochondrial calcium accumulation, also being implicated in cell death. In this study, we compared the effect of carvedilol on the cardiac MPT induced by calcium and phosphate (Ca/Pi) and calcium/carboxyatractyloside (Ca/Catr). Oxidative stress plays a major role in MPT induction by Ca/Pi, leading to the oxidation of protein thiol groups, in contrast with Ca/Catr, where such oxidation is secondary to MPT induction and is not caused by oxidative stress. Materials and methods: Mitochondria were isolated from rat hearts and parameters related to MPT induction were evaluated (n=5 for each inducer): mitochondrial swelling and oxidation of protein thiol groups (both measured by spectrophotometry). Results: Using Ca/Pi, carvedilol protected mitochondria from MPT induction, particularly in its high conductance form. Its effect was demonstrated by analyzing the decrease in mitochondrial swelling amplitude. Simultaneously, we observed inhibition of protein thiol group oxidation (p<0.001). By contrast, carvedilol did not show any protective effect with Ca/Catr. Conclusions: Carvedilol was only effective against the MPT when the oxidation of protein thiol groups was the cause and not the consequence of the MPT phenomenon. The results clearly show that during myocardial aggressions (ischemia and reperfusion, for example), the protective effect of carvedilol is primarily due to an antioxidant mechanism, inhibiting the production and effects of reactive oxygen species

Structural and magnetic properties of nanogranular BaTiO3-CoFe2O4 thin films deposited by laser ablation on Si/Pt substrates

Thin film nanogranular composites of cobalt ferrite (CoFe2O 4) dispersed in a barium titanate (BaTiO3) matrix were deposited by laser ablation with different cobalt ferrite concentrations (x). The films were polycrystalline and composed by a mixture of tetragonal- BáTiO3 and CoFe2O4 with the cubic spinnel structure. A slight (111) barium titanate phase orientation and (311) CoFe2O4 phase orientation was observed. As the concentration of the cobalt ferrite increased, the grain size of the BaTiO 3 phase decreased, from 91nm to 30nm, up to 50% CoFe 2O4 concentration, beyond which the BaTiO3 grain size take values in the range 30-35nm. On the other hand the cobalt ferrite grain size did not show a clear trend with increasing cobalt ferrite concentration, fluctuating in the range 25nm to 30nm. The lattice parameter of the CoFe2O4 phase increased with increasing x. However, it was always smaller than the bulk value indicating that, in the films, the cobalt ferrite was under compressive stress that was progressively relaxed with increasing CoFe2O4 concentration. The magnetic measurements showed a decrease of coercive field with increasing x, which was attributed to the relaxation of the stress in the films and to the increase of particle agglomeration in bigger polycrystalline clusters with increasing cobalt ferrite concentration.This work has been financially supported by the Portuguese Foundation for Science and Technology (FCT), through the project POCI/CTM/60181/2004