Wiki como fator promotor de resolução de problemas : um estudo de caso no ensino da informática

Mestrado em Didática - TecnologiaO ensino da modulação de dados, na área da informática, representa dificuldades de aprendizagem na teoria de Bases de Dados e, assim, tornouse urgente e fundamental experimentar e encontrar novas estratégias que promovam o sucesso nestes conteúdos. Neste projeto de investigação foi utilizada uma metodologia de investigação qualitativa de estudo de caso. O estudo faz parte de um conjunto de três investigações em rede, sobre o impacto da utilização da ferramenta wiki no ensino da Informática baseado na resolução de problemas. Assim, e com base no enquadramento teórico, foram desenvolvidas estratégias de ensino baseadas na resolução de ploblemas no módulo 13 da disciplina de Programação e Sistemas de Informação (PSI), onde o investigador assumia o papel de investigador não participante. O estudo envolveu 26 alunos do curso Profissional de nível 4, do 2º ano do ciclo de formação do Agrupamento de Escolas Dr. Serafim Leite, de São João da Madeira. O estudo encontra-se estruturado em quatro etapas. Na 1ª etapa faz-se a planificação da investigação. Na 2ª etapa, desenvolve-se e aplica-se o questionário inicial que tem como objetivos: caracterizar os alunos, conhecer a familiaridade desses alunos com as Tecnologias da Informação e da Comunicação (nomeadamente a wiki) e compreender a atitude dos alunos face à resolução de problemas no ensino da informática. Na 3ª etapa elabora-se a planificação e a descrição da implementação das novas estratégias de ensino que incluem a utilização da ferramenta wiki na atividade em PSI. Na 4ª etapa aplica-se o questionário final que foi elaborado com base no questionário inicial e aplicado após a implementação da metodologia, tendo seguido a mesma estrutura e escala de respostas do questionário inicial. Foram, ainda, incluídos os registos de observação de aula e os registos dos alunos na wiki, para a triangulação dos dados. Com base nos resultados obtidos, verificou-se que a ferramenta wiki promoveu uma aprendizagem baseada na resolução de problemas, pois os alunos passaram a interagir muito mais por iniciativa própria, deste modo, promovendo a aprendizagem colaborativa e ultrapassando dificuldades e contratempos em conjunto, expondo soluções cada vez melhores para os problemas, quer ao nível da qualidade, quer ao nível do conteúdo.The teaching of Data Modelling in the information technology area represents learning difficulties in the theory of data base and so, it has become urgent and essential to experience and find new strategies that may promote success in these contents. This research project used a qualitative research methodology of a case study. This study is part of a set of three network investigations about the impact of the use of the Wiki tool in the Teaching of Computer Science based upon problem solving. Therefore, based on a theoretical framework, teaching strategies have been developed centred on problem solving concerning module 13 of the subject “Programming and Information Systems (PSI)”, where the researcher had the role of a non-participating investigator. The study involved 26 students of the Professional Course, level 4, 2nd year of the training cycle of the Dr. Serafim Leite School Grouping, in São João da Madeira. The study is structured in four steps. The 1st step is about planning the research. The 2nd step consists of developing and providing an initial questionnaire with the following aims: characterize the students; know the familiarity of these students with the Information and Communication Technologies (mainly the wiki tool) and understand their attitude towards problem solving in the education of Computer Science. The 3rd step elaborates the planning and the description of the implementation of the new teaching strategies which include the use of the wiki tool in the activity of the subject PSI. The 4th step refers to the final questionnaire, which was made based on the initial questionnaire and applied after the implementation of the methodology, having followed the same structure and scale of answers of the initial questionnaire. The register of class observation and the students’ register in the wiki were also included, for the triangulation of data. Based upon the results obtained one can say that the wiki tool promoted a learning process based on problem solving, as students started to interact much more on their own initiative, this way promoting collaborative learning and overcoming difficulties and setbacks together, exposing increasingly better solutions for the problems, both in what concerns quality and content

Diabetic rats lose A2A receptor-mediated facilitation of ileal myenteric cholinergic neurotransmission

Enteric dysmotility is a long-term complication of Diabetes mellitus that causes significant discomfort in 76% of diabetic outpatients. Knowing that purines may be involved in synaptic transmission modifications in the CNS of diabetic rats, we decided to investigate if purinergic dysfunction could also play a role in diabetic enteric neuropathy in rats.info:eu-repo/semantics/publishedVersio

Bradykinin-induced Ca2+ signaling in human subcutaneous fibroblasts involves ATP release via hemichannels leading to P2Y12 receptors activation

Chronic musculoskeletal pain involves connective tissue remodeling triggered by inflammatory mediators, such as bradykinin. Fibroblast cells signaling involve changes in intracellular Ca2+ ([Ca2+]i). ATP has been related to connective tissue mechanotransduction, remodeling and chronic inflammatory pain, via P2 purinoceptors activation. Here, we investigated the involvement of ATP in bradykinin-induced Ca2+ signals in human subcutaneous fibroblasts. Bradykinin, via B2 receptors, caused an abrupt rise in [Ca2+]i to a peak that declined to a plateau, which concentration remained constant until washout. The plateau phase was absent in Ca2+-free medium; [Ca2+]i signal was substantially reduced after depleting intracellular Ca2+ stores with thapsigargin. Extracellular ATP inactivation with apyrase decreased the [Ca2+]i plateau. Human subcutaneous fibroblasts respond to bradykinin by releasing ATP via connexin and pannexin hemichannels, since blockade of connexins, with 2- octanol or carbenoxolone, and pannexin-1, with 10Panx, attenuated bradykinin-induced [Ca2+]i plateau, whereas inhibitors of vesicular exocytosis, such as brefeldin A and bafilomycin A1, were inactive. The kinetics of extracellular ATP catabolism favors ADP accumulation in human fibroblast cultures. Inhibition of ectonucleotidase activity and, thus, ADP formation from released ATP with POM-1 or by Mg2+ removal from media reduced bradykinin-induced [Ca2+]i plateau. Selective blockade of the ADP-sensitive P2Y12 receptor with AR-C66096 attenuated bradykinin [Ca2+]i plateau, whereas the P2Y1 and P2Y13 receptor antagonists, respectively MRS 2179 and MRS 2211, were inactive. Human fibroblasts exhibited immunoreactivity against connexin-43, pannexin-1 and P2Y12 receptor. Bradykinin induces ATP release from human subcutaneous fibroblasts via connexin and pannexin-1-containing hemichannels leading to [Ca2+]i mobilization through the cooperation of B2 and P2Y12 receptors

Calcium signaling and the novel anti-proliferative effect of the UTP-sensitive P2Y11 receptor in rat cardiac myofibroblasts

During myocardial ischemia and reperfusion both purines and pyrimidines are released into the extracellular milieu, thus creating a signaling wave that propagates to neighboring cells via membrane-bound P2 purinoceptors activation. Cardiac fibroblasts (CF) are important players in heart remodeling, electrophysiological changes and hemodynamic alterations following myocardial infarction. Here, we investigated the role UTP on calcium signaling and proliferation of CF cultured from ventricles of adult rats. Co-expression of discoidin domain receptor 2 and -smooth muscle actin indicate that cultured CF are activated myofibroblasts. Intracellular calcium ([Ca2+]i) signals were monitored in cells loaded with Fluo-4 NW. CF proliferation was evaluated by the MTT assay. UTP and the selective P2Y4 agonist, MRS4062, caused a fast desensitizing [Ca2+]i rise originated from thapsigargin-sensitive internal stores, which partially declined to a plateau providing the existence of Ca2+ in the extracellular fluid. The biphasic [Ca2+]i response to UTP was attenuated respectively by P2Y4 blockers, like reactive blue-2 and suramin, and by the P2Y11 antagonist, NF340. UTP and the P2Y2 receptor agonist MRS2768 increased, whereas the selective P2Y11 agonist NF546 decreased, CF growth; MRS4062 was ineffective. Blockage of the P2Y11receptor or its coupling to adenylate cyclase boosted UTP-induced CF proliferation. Confocal microscopy and Western blot analysis confirmed the presence of P2Y2, P2Y4 and P2Y11 receptors. Data indicate that besides P2Y4 and P2Y2 receptors which are responsible for UTP-induced [Ca2+]i transients and growth of CF, respectively, synchronous activation of the previously unrecognized P2Y11 receptor may represent an important target for anti-fibrotic intervention in cardiac remodeling

2,4,5-Triaminopyrimidines as blue fluorescent probes for cell viability monitoring: synthesis, photophysical properties, and microscopy applications

Monitoring cell viability is critical in cell biology, pathology, and drug discovery. Most cell viability assays are cell-destructive, time-consuming, expensive, and/or hazardous. Herein, we present a series of newly synthesized 2,4,5-triaminopyrimidine derivatives able to discriminate between live and dead cells. To our knowledge, these compounds are the first fluorescent nucleobase analogues (FNAs) with cell viability monitoring potential. These new fluorescent molecules are synthesized using highly efficient and cost- effective methods and feature unprecedented photophysical properties (longer absorption and emission wavelengths, environment-sensitive emission, and unprecedented brightness within FNAs). Using a live– dead Saccharomyces cerevisiae cell and theoretical assays, the fluorescent 2,4,5-triaminopyrimidine derivatives were found to specifically accumulate inside dead cells by interacting with dsDNA grooves, thus paving the way for the emergence of novel and safe fluorescent cell viability markers emitting in the blue region. As the majority of commercially available viability dyes emit in the green to red region of the visible spectrum, these novel markers might be useful to meet the needs of blue markers for co-staining combinations

Histamine Induces ATP Release from Human Subcutaneous Fibroblasts, via Pannexin-1 Hemichannels, Leading to Ca2+Mobilization and Cell Proliferation

Changes in the regulation of connective tissue ATP-mediated mechano-transduction and remodeling may be an important link to the pathogenesis of chronic pain. It has been demonstrated that mast cell-derived histamine plays an important role in painful fibrotic diseases. Here we analyzed the involvement of ATP in the response of human subcutaneous fibroblasts to histamine. Acute histamine application caused a rise in intracellular Ca(2+) ([Ca(2+)]i) and ATP release from human subcutaneous fibroblasts via H1 receptor activation. Histamine-induced [Ca(2+)]i rise was partially attenuated by apyrase, an enzyme that inactivates extracellular ATP, and by blocking P2 purinoceptors with pyridoxal phosphate-6-azo(benzene-2,4-disulfonic acid) tetrasodium salt and reactive blue 2. [Ca(2+)]i accumulation caused by histamine was also reduced upon blocking pannexin-1 hemichannels with (10)Panx, probenecid, or carbenoxolone but not when connexin hemichannels were inhibited with mefloquine or 2-octanol. Brefeldin A, an inhibitor of vesicular exocytosis, also did not block histamine-induced [Ca(2+)]i mobilization. Prolonged exposure of human subcutaneous fibroblast cultures to histamine favored cell growth and type I collagen synthesis via the activation of H1 receptor. This effect was mimicked by ATP and its metabolite, ADP, whereas the selective P2Y1 receptor antagonist, MRS2179, partially attenuated histamine-induced cell growth and type I collagen production. Expression of pannexin-1 and ADP-sensitive P2Y1 receptor on human subcutaneous fibroblasts was confirmed by immunofluorescence confocal microscopy and Western blot analysis. In conclusion, histamine induces ATP release from human subcutaneous fibroblasts, via pannexin-1 hemichannels, leading to [Ca(2+)]i mobilization and cell growth through the cooperation of H1 and P2 (probably P2Y1) receptors.info:eu-repo/semantics/publishedVersio