Aplicação de ensaios não destrutivos por correntes induzidas à caracterização de propriedades eléctricas de materiais processados no estado sólido

Dissertação apresentada na Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa para obtenção de Grau de Mestre em Engenharia MecânicaO processamento de materiais no estado sólido, nomeadamente a soldadura e o processamento por fricção linear, permite modificar a microestrutura do material melhorando as suas propriedades mecânicas. A condutividade eléctrica também é alterada, embora este fenómeno não seja explorado como mais-valia tecnológica ou aplicação industrial. A caracterização dos campos de condutividade, assim como a compreensão dos fenómenos metalúrgicos que lhe estão na origem também não está convenientemente descrita. No entanto, esta informação é fundamental quando se pretende aplicar ensaios não destrutivos por métodos eléctricos. O objectivo deste trabalho é caracterizar e compreender as variações dos campos de condutividade eléctrica em diferentes ligas de alumínio processadas no estado sólido. Foram realizados ensaios de processamento por fricção linear nas ligas AA1100, AA7075- T6, AA6061-T6, AA5083-H111 e AlScMg com diferentes parâmetros. Desenvolveram-se os meios laboratoriais para caracterizar os perfis de condutividades a diferentes profundidades, e esses resultados foram comparados com a análise metalográfica e de dureza. Verificou-se que as variações de condutividade são significativas em algumas condições de processamento, mas quase nulas noutras, tendo-se identificado os fenómenos responsáveis por esse comportamento. Os perfis de condutividade reproduzem com rigor as diferentes zonas do material processado, e encontrou-se uma estreita correlação com os perfiz de dureza

Evaluation of a Large-Scale Biomedical Data Annotation Initiative

Background: This study describes a large-scale manual re-annotation of data samples in the Gene Expression Omnibus (GEO), using variables and values derived from the National Cancer Institute thesaurus. A framework is described for creating an annotation scheme for various diseases that is flexible, comprehensive, and scalable. The annotation structure is evaluated by measuring coverage and agreement between annotators. Results: There were 12,500 samples annotated with approximately 30 variables, in each of six disease categories – breast cancer, colon cancer, inflammatory bowel disease (IBD), rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), and Type 1 diabetes mellitus (DM). The annotators provided excellent variable coverage, with known values for over 98% of three critical variables: disease state, tissue, and sample type. There was 89% strict inter-annotator agreement and 92% agreement when using semantic and partial similarity measures. Conclusion: We show that it is possible to perform manual re-annotation of a large repository in a reliable manner

Bridging heterogeneous networks in challenging and disruptive maritime environments

In this work, we describe the development of a system that aims to deal with different communication means when operating in a network of heterogeneous systems with ad-hoc behaviour that has proved helpful in real-life scenarios. Using the LSTS toolchain, we can support the deployment of ocean, surface and air vehicles, providing transparent communication between them in a fashion way.Peer Reviewe

Identification of agonists for a group of human odorant receptors

Olfaction plays a critical role in several aspects of the human life. Odorants are detected by hundreds of odorant receptors (ORs) which belong to the superfamily of G protein-coupled receptors. These receptors are expressed in the olfactory sensory neurons of the nose. The information provided by the activation of different combinations of ORs in the nose is transmitted to the brain, leading to odorant perception and emotional and behavioral responses. There are ~400 intact human ORs, and to date only a small percentage of these receptors (~10%) have known agonists. The determination of the specificity of the human ORs will contribute to a better understanding of how odorants are discriminated by the olfactory system. In this work, we aimed to identify human specific ORs, that is, ORs that are present in humans but absent from other species, and their corresponding agonists. To do this, we first selected 22 OR gene sequences from the human genome with no counterparts in the mouse, rat or dog genomes. Then we used a heterologous expression system to screen a subset of these human ORs against a panel of odorants of biological relevance, including foodborne aroma volatiles. We found that different types of odorants are able to activate some of these previously uncharacterized human ORs

Sense-antisense pairs in mammals: functional and evolutionary considerations

Analysis of a catalog of S-AS pairs in the human and mouse genomes revealed several putative roles for natural antisense transcripts and showed that some are artifacts of cDNA library construction

Unveiling the Impact of the Genomic Architecture on the Evolution of Vertebrate microRNAs

Eukaryotic genomes frequently exhibit interdependency between transcriptional units, as evidenced by regions of high gene density. It is well recognized that vertebrate microRNAs (miRNAs) are usually embedded in those regions. Recent work has shown that the genomic context is of utmost importance to determine miRNA expression in time and space, thus affecting their evolutionary fates over long and short terms. Consequently, understanding the inter- and intraspecific changes on miRNA genomic architecture may bring novel insights on the basic cellular processes regulated by miRNAs, as well as phenotypic evolution and disease-related mechanisms

miRIAD-integrating microRNA inter- and intragenic data

MicroRNAs (miRNAs) are a class of small (similar to 22 nucleotides) non-coding RNAs that post-transcriptionally regulate gene expression by interacting with target mRNAs. A majority of miRNAs is located within intronic or exonic regions of protein-coding genes (host genes), and increasing evidence suggests a functional relationship between these miRNAs and their host genes. Here, we introduce miRIAD, a web-service to facilitate the analysis of genomic and structural features of intragenic miRNAs and their host genes for five species (human, rhesus monkey, mouse, chicken and opossum). miRIAD contains the genomic classification of all miRNAs (inter-and intragenic), as well as classification of all protein-coding genes into host or non-host genes (depending on whether they contain an intragenic miRNA or not). We collected and processed public data from several sources to provide a clear visualization of relevant knowledge related to intragenic miRNAs, such as host gene function, genomic context, names of and references to intragenic miRNAs, miRNA binding sites, clusters of intragenic miRNAs, miRNA and host gene expression across different tissues and expression correlation for intragenic miRNAs and their host genes. Protein-protein interaction data are also presented for functional network analysis of host genes. In summary, miRIAD was designed to help the research community to explore, in a user-friendly environment, intragenic miRNAs, their host genes and functional annotations with minimal effort, facilitating hypothesis generation and in-silico validations