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Austenite instability and precipitation behavior of high nitrogen stainless steels
No full textNitrogen is a strong austenite stabilizer and improves the mechanical properties and the corrosion resistance of austenitic stainless steels. For these reasons, nitrogen addition to steel has been extensively studied in the last 40 years. This chapter presents a literature review since 1926, when a pioneer study on the effects of nitrogen in iron-based alloys was reported. The maximum solubility of nitrogen in stainless steels is high, although it decreases considerably at temperatures below 1000ºC. Therefore, depending on the composition, high nitrogen austenitic stainless steels can undergo different phase transformations during exposure to temperatures ranging between 500 and 1000oC. Continuous and discontinuous precipitations of chromium nitride, as well as ferrite and sigma phase formation, have been observed and, as a result of these phase transformations, a loss of toughness and lower corrosion resistance are frequently detected. The aim of this chapter is to present and discuss the austenite stability and illustrate the precipitation behavior of high nitrogen austenitic stainless steels. Three different high nitrogen stainless steels are used in order to highlight stabilization/destabilization effects and microstructural features associated with the presence/depletion of nitrogen. The nucleation of discontinuous precipitation of chromium nitride and its growth kinetics are discussed and transformation models are presented.\ud
Keywords: high nitrogen steels, austenite stability, chromiumCNPqCAPESFAPES
Transcriptional profiling reveals intrinsic mRNA alterations in multipotent mesenchymal stromal cells isolated from bone marrow of newly-diagnosed type 1 diabetes patients
No full textAbstract
Background
Bone marrow multipotent mesenchymal stromal cells (MSCs) are a diverse subset of precursors that contribute to the homeostasis of the hematopoietic niche. MSCs can be isolated and expanded in vitro and have unique immunomodulatory and regenerative properties that make them attractive for the treatment of autoimmune diseases, including type 1 diabetes (T1D). Whether autologous or allogeneic MSCs are more suitable for therapeutic purposes has not yet been established. While autologous MSCs may present abnormal function, allogeneic cells may be recognized and rejected by the host immune system. Thus, studies that investigate biological characteristics of MSCs isolated from T1D patients are essential to guide future clinical applications.
Methods
Bone marrow-derived MSCs from recently diagnosed type 1 diabetes patients (T1D-MSCs) were compared with those from healthy individuals (C-MSCs) for morphological and immunophenotypic characteristics and for differentiation potential. Bioinformatics approaches allowed us to match absolute and differential gene expression of several adhesion molecules, immune mediators, growth factors, and their receptors involved with hematopoietic support and immunomodulatory properties of MSCs. Finally, the differentially expressed genes were collated for functional pathway enrichment analysis.
Results
T1D-MSCs and C-MSCs were similar for morphology, immunophenotype, and differentiation potential. Our absolute gene expression results supported previous literature reports, while also detecting new potential molecules related to bone marrow-derived MSC functions. T1D-MSCs showed intrinsic abnormalities in mRNA expression, including the immunomodulatory molecules VCAM-1, CXCL12, HGF, and CCL2. Pathway analyses revealed activation of sympathetic nervous system and JAK STAT signaling in T1D-MSCs.
Conclusions
Collectively, our results indicate that MSCs isolated from T1D patients present intrinsic transcriptional alterations that may affect their therapeutic potential. However, the implications of these abnormalities in T1D development as well as in the therapeutic efficacy of autologous MSCs require further investigation
O estudo de funções no ensino médio: uma proposta alternativa
No full textO foco deste livro é voltado então para Ensino Médio de Álgebra, mais especificamente para o tema função. Este assunto foi escolhido uma vez que compreendemos que um tratamento algébrico da matemática num estilo mais ‘tradicional’, no qual se enfatize fórmulas, em detrimento da compreensão, pode gerar grandes dificuldades de aprendizagem, o que nos remete a buscar possibilidades de se ensinar Álgebra de forma mais significativa e atraente. Nesse sentido, esta obra se estrutura em cinco capítulos. Os três primeiros têm como propósito discutir sobre o embasamento teórico que deu suporte as atividades alternativas desenvolvidas para o ensino de funções no nível médio. O quarto capítulo é destinado à apresentação da parte prática do trabalho, neste capítulo são focalizadas as atividades elaboradas para o ensino e aprendizagem de funções destinadas ao nível médio de ensino. Por fim, o encerramento do livro se dá com as considerações finais, nas quais enfatizamos que a proposta apresentada neste livro representa um contexto rico e desafiador de aprendizagem tanto para o aluno quanto para o professor
Molecular diagnosis and genetic diversity of tick-borne Anaplasmataceae agents infecting the African buffalo Syncerus caffer from Marromeu Reserve in Mozambique
No full textAbstract\ud
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Background\ud
Tick-borne diseases (TBDs) are very important in relation to domestic ruminants, but their occurrence among wild ruminants, mainly in the African buffalo Syncerus caffer, remains little known.\ud
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Methods\ud
Molecular diagnostic methods were applied to detect Anaplasma marginale, Anaplasma centrale, Anaplasma phagocytophilum, Ehrlichia ruminantium and Ehrlichia chaffeensis in 97 blood samples of African buffalo captured at the Marromeu Reserve in Mozambique. Molecular detection of agents belonging to the family Anaplasmataceae were based on conventional and qPCR assays based on msp5, groEL, 16S rRNA, msp2, pCS20 and vlpt genes. Phylogenetic reconstruction of new Anaplasma isolates detected in African buffalo was evaluated based on msp5, groEL and 16S rRNA genes.\ud
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Results\ud
All the animals evaluated were negative for specific PCR assays for A. phagocytophilum, E. ruminantium and E. chaffeensis, but 70 animals were positive for A. marginale, showing 2.69 × 100 up to 2.00 × 105 \ud
msp1β copies/μl. This result overcomes the conventional PCR for A. marginale based on msp5 gene that detected only 65 positive samples. Sequencing and phylogenetic analyses were performed for selected positive samples based on the genes msp5, groEL and 16S rRNA. Trees inferred using different methods separated the 29 msp5 sequences from buffalo in two distinct groups, assigned to A. centrale and A. marginale. The groEL sequences determined for African buffalo samples revealed to be more heterogeneous and inferred trees could not assign them to any species of Anaplasma despite being more related to A. marginale and A. centrale. The highly conserved 16S rRNA gene sequences suggested a close relationship of the new 16 sequences with A. centrale/A. marginale, A. platys and A. phagocytophilum.\ud
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Conclusions\ud
Our analysis suggests that different species of Anaplasma are simultaneously present in the African buffalo. To the best of our knowledge, this is the first study that diagnosed Anaplasma spp. in the African buffalo and inferred the taxonomic status of new isolates with different gene sequences. The small fragment of msp5 sequences revealed to be a good target for phylogenetic positioning of new Anaplasma spp. isolates.This work was supported by grants from the FAPESP (Fundação de Amparo\ud
à Pesquisa do Estado de São Paulo) delivered to RZM and the Brazilian\ud
Agency CNPq within the PROAFRICA to MMGT
Immune response pattern in recurrent Plasmodium vivax malaria
No full textAbstract\ud
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Background\ud
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Plasmodium vivax is the causative agent of human malaria of large geographic distribution, with 35 million cases annually. In Brazil, it is the most prevalent species, being responsible by around 70 % of the malaria cases.\ud
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Methods\ud
A cross-sectional study was performed in Manaus (Amazonas, Brazil), including 36 adult patients with primary malaria, 19 with recurrent malaria, and 20 endemic controls. The ex vivo phenotypic features of circulating leukocyte subsets (CD4+ T-cells, CD8+ T-cells, NK, NKT, B, B1 and Treg cells) as well as the plasmatic cytokine profile (IL-2, IL-4, IL-6, IL-10, TNF and IFN-γ) were assessed, aiming at establishing patterns of immune response characteristic of primary malaria vs recurrent malaria as compared to endemic controls.\ud
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Results\ud
The proportion of subjects with high levels of WBC was reduced in malaria patients as compared to the endemic control. Monocytes were diminished particularly in patients with primary malaria. The proportion of subjects with high levels of all lymphocyte subsets was decreased in all malaria groups, regardless their clinical status. Decreased proportion of subjects with high levels of CD4+ and CD8+ T-cells was found especially in the group of patients with recurrent malaria. Data analysis indicated significant increase in the proportion of the subjects with high plasmatic cytokine levels in both malaria groups, characterizing a typical cytokine storm. Recurrent malaria patients displayed the highest plasmatic IL-10 levels, that correlated directly with the CD4+/CD8+ T-cells ratio and the number of malaria episodes.\ud
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Conclusion\ud
The findings confirm that the infection by the P. vivax causes a decrease in peripheral blood lymphocyte subsets, which is intensified in the cases of “recurrent malaria”. The unbalanced CD4+/CD8+ T-cells ratio, as well as increased IL-10 levels were correlated with the number of recurrent malaria episodes. These results suggest that the gradual remodelling of the immune response is dependent on the repeated exposure to the parasite, which involves a strict control of the immune response mediated by the CD4+/CD8+ T-cell unbalance and exacerbated IL-10 secretion.Financial support was provided by grants from FAPEAM, CNPq and Programa\ud
do Instituto Nacional de Ciência e Tecnologia em Vacinas (INCT-Vacina). YOC\ud
was awarded with a fellowship from INCT-Vacina/CNPq and AGC with a fellow‑\ud
ship from CAPES (PhD students). AM and ATC are level 2 CNPq research fellow.\ud
MVGL and OAMF are level 1 CNPq research fellows. CRFM, OAMF and ATC are\ud
FAPEAM research fellows (PVS Programme - PECTI-AM/PG#019/2013). JGCdR\ud
received postdoctoral fellowship from CAPES (PNPD/CAPES programme). The\ud
funders had no role in study design, data collection and analysis, decision to\ud
publish, or preparation of the manuscript
Aprendizado incremental e classe-incremental por meio da atualização de árvores geradoras em florestas de caminhos ótimos
No full textAlgoritmos com capacidade classe-incremental, em que é preciso manter modelos de classificação atualizados a partir de dados que aparecem ao longo do tempo, são importantes em diversas aplicações. Apresentamos neste artigo um algoritmo para atualização de florestas de caminhos ótimos capaz de incluir uma nova instância mantendo as propriedades das árvores de caminhos ótimos. Além de uma prova demonstrando que o algoritmo mantém a estrutura das árvores de caminhos ótimos em tempo linear, as evidências experimentais demonstram a aplicabilidade do método, que partindo de um modelo limitado, e após a inclusão de múltiplas instâncias, é capaz de alcançar a mesma acurácia de um classificador treinado considerando o conjunto completo de treinamento.Class-incremental algorithms, where there is the need to update classification models with data that emerges over time, are important in many applications.We report an algorithm for updating optimum-path forests capable of including a new instance, maintaining the properties of the optimum-path trees. In addition to a proof demonstrating that the algorithm maintains the structure of the trees in linear time, the experimental evidence shows the applicability of the method, which starting from a limited model, and after the inclusion of multiple instances, is able to achieve the same accuracy of a classifier trained with the full training set.FAPESP (15/13504-4, 14/04889-5, e 15/24652-2
YBYRÁ facilitates comparison of large phylogenetic trees
No full textAbstract\ud
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Background\ud
The number and size of tree topologies that are being compared by phylogenetic systematists is increasing due to technological advancements in high-throughput DNA sequencing. However, we still lack tools to facilitate comparison among phylogenetic trees with a large number of terminals.\ud
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Results\ud
The “YBYRÁ” project integrates software solutions for data analysis in phylogenetics. It comprises tools for (1) topological distance calculation based on the number of shared splits or clades, (2) sensitivity analysis and automatic generation of sensitivity plots and (3) clade diagnoses based on different categories of synapomorphies. YBYRÁ also provides (4) an original framework to facilitate the search for potential rogue taxa based on how much they affect average matching split distances (using MSdist).\ud
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Conclusions\ud
YBYRÁ facilitates comparison of large phylogenetic trees and outperforms competing software in terms of usability and time efficiency, specially for large data sets. The programs that comprises this toolkit are written in Python, hence they do not require installation and have minimum dependencies. The entire project is available under an open-source licence at \ud
http://www.ib.usp.br/grant/anfibios/researchSoftware.html\ud
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.YBYRÁ was first introduced as a poster at the XXXII Willi Hennig Meeting\ud
(Rostock, Germany, 2013). I thank Fernando P. L. Marques, Taran Grant and two\ud
anonymous reviewers for their insightful suggestions. The name ybyrá is a\ud
noun in Tupi which means tree, stick, tree, rod, stalk, lance or spear. I thank\ud
Miguel T. Rodrigues for suggesting the name. This work was supported by\ud
Fundação de Amparo à Pesquisa do Estado de São Paulo in Brazil (FAPESP\ud
Proc. No. 2009/13561-5, 2013/05958-8, and 2012/10000-5)
Effects of nutrition education on recurrent coronary events after percutaneous coronary intervention: A randomized clinical trial
No full textAbstract\ud
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Background\ud
Changes in lifestyle include a healthy diet. However, due to different educational approaches, the effects of nutritional counselling are still not very encouraging and require further study. The objective of this study was to analyse the effectiveness of a nutrition education intervention program on mortality and recurrence of cardiovascular events evaluated after one and four years of follow-up.\ud
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Methods\ud
A randomized clinical trial was performed at a public hospital in Brazil with 200 patients who had recently undergone elective percutaneous coronary intervention (PCI). In addition to the traditional care, the patients allocated to the intervention group attended nutrition education workshops that adopted a constructivist approach towards behavioural change for six months. Primary outcome was death, and secondary outcomes were acute myocardial infarction (AMI), revascularization with re-PCI, or coronary artery bypass graft (CABG) surgery. The magnitude of the first year effect was calculated by the absolute risk reduction, and the risk ratio was calculated as a measure of the cumulative incidence of events after four years. The critical p-value was assumed as 5%.\ud
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Results\ud
After one year of follow-up, in the intervention and control groups, respectively, there were 5 and 7 deaths (p = 0.53); 5 and 6 AMIs (p = 0.73); 4 and 6 re-PCIs (p = 0.50); and 4 and 4 CABGs (p = 0.98). After four years, the risk ratios between intervention and control groups were 0.75 (95% CI 0.35–1.58) for death, 0.89 (95% CI 0.34–2.28) for AMI, 0.86 (95% CI 0.40–1.84) for re-PCI, and 1.14 (95% CI 0.38–3.40) for CABG.\ud
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Conclusion\ud
Although differences in events between the two groups were not significant, data suggest that the lower number of events observed in the intervention group is most notable with the longer follow-up.\ud
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Trial registration number\ud
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NCT01028066\ud
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. Registered 8 December 2009, retrospectively registered.Fundação de Amparo a Pesquisa do Estado de São Paulo (FAPESP) provided\ud
the financial support for this research, case number 2007/54652-8
