Constructal design of an arterial bypass graft

Arterial bypass grafts tend to fail after some years due to intimal hyperplasia\u2014an abnormal proliferation of smooth muscle cells that leads to stenosis and graft occlusion. In this regard and on the basis of the constructal design method, this study seeks to investigate the effect of geometric parameters\u2014stenosis degree, junction angle, and diameter ratio\u2014on the flow through a bypass graft circumventing an idealized, partially stenosed coronary artery. The computational model assumes a steady\u2010state Newtonian fluid flow through an artery stenosis degree from 25% to 75%. A computational fluid dynamics model and a response surface methodology were employed to assess the effects of the project parameters on pressure drop. As diameter ratio increases to 1 and the junction angle decreases to 30\ub0, the pressure drop decreases and there is a considerable dependence of pressure drop on the stenosis degree. The effects of the diameter ratio are more pronounced than those of junction angle on the velocity field and wall shear stress. The application of the constructal design method in hemodynamicsmight be a good alternative to provide configurations with enhanced performance and to provide valuable results to the understanding of biological flows

Self-ligating versus conventional metallic brackets on Streptococcus mutans retention:A systematic review

ABSTRACT Objective: The present study aimed to review the literature systematically and assess comparatively whether self-ligating metallic brackets accumulate less Streptococcus mutans biofilm than conventional metallic brackets. Material and methods: The systematic search was performed following PRISMA guidelines and registration in PROSPERO. Seven electronic databases (Google Scholar, LILACS, Open Grey, PubMed, SciELO, ScienceDirect, and Scopus) were consulted until April 2016, with no restriction of language and time of publication. Only randomized clinical studies verifying S. mutans colonization in metallic brackets (self-ligating and conventional) were included. All steps were performed independently by two operators. Results: The search resulted in 546 records obtained from the electronic databases. Additionally, 216 references obtained from the manual search of eligible articles were assessed. Finally, a total of 5 studies were included in the qualitative synthesis. In 1 study, the total bacterial count was not different among self-ligating and conventional brackets, whereas in 2 studies the amount was lower for self-ligating brackets. Regarding the specific count of S. mutans, 2 studies showed less accumulation in self-ligating than in conventional brackets. Conclusion: Based on the limited evidence, self-ligating metallic brackets accumulate less S. mutans than conventional ones. However, these findings must be interpreted in conjunction with particularities individual for each patient – such as hygiene and dietary habits, which are components of the multifactorial environment that enables S. Mutans to proliferate and keep retained in the oral cavity.</jats:p

Study of efficiency time of recombinant DNA insulin via accelerated life testing and interval censoring.

This paper aims to study the efficiency of recombinant DNA insulin via models for accelerated life tests. The potency loss of these insulin products was evaluated periodically, subject to the conditions of temperature of 8?C, 25?C and 37?C. Insulin samples with potency at less than 100% were considered unfit for consumption, which characterizes the event of interest. Samples suitable for consumption were considered to be censored. The response variable was observed periodically for 736 days. For data analysis, statistical models of stress-response regression were used. The deterministic part of these models is the Arrhenius model because the stress variable is the temperature, while the probabilistic part was comprised of the Exponential, Weibull, and Log-normal models. The techniques of accelerated life tests proved adequate to address the time of potency loss of the insulin for the various temperature levels. The times of occurrence of the events were treated in three different ways, which were compared in this study. First, interval censoring was considered, or only the upper and lower limits of the interval in which the failure occurred were known. Then, the midpoint of this interval was considered as a failure time. Finally, only the lower limit of the interval in which the failure occurred was considered. According to the results, it is concluded that the use of the interval lower limit is more appropriate for estimating the reliability curves, as the estimates are closer to those using interval censoring then using the midpoint of the interval. For the specific case of the recombinant DNA insulin data, it was observed that the Arrhenius-Weibull model and the Arrhenius-lognormal are suitable for adjusting the data. It follows also that the temperature affects the power of the insulin: The higher the temperature are, the lesser the efficiency

Mapping the stellar population and gas excitation of MaNGA galaxies with MEGACUBES. Results for AGN versus control sample

We present spaxel-by-spaxel stellar population fits for the $\sim$10 thousand MaNGA datacubes. We provide multiple extension fits files, nominated as MEGACUBES, with maps of several properties as well as emission-line profiles that are provided for each spaxel. All the MEGACUBES are available through a web interface (https://manga.linea.org.br/ or http://www.if.ufrgs.br/~riffel/software/megacubes/). We also defined a final Active Galactic Nuclei (AGN) sample, as well as a control sample matching the AGN host galaxy properties. We have analysed the stellar populations and spatially resolved emission-line diagnostic diagrams of these AGNs and compared them with the control galaxies sample. We find that the relative fractions of young ($t \leq$56 Myr) and intermediate-age (100 Myr $\leq t \leq$ 2 Gyr) show predominantly a positive gradient for both AGNs and controls. The relative fraction of intermediate-age stellar population is higher in AGN hosts when compared to the control sample, and this difference becomes larger for higher [O III] luminosity AGNs. We attribute this to the fact that extra gas is available in these more luminous sources and that it most likely originates from mass-loss from the intermediate-age stars. The spatially resolved diagnostic diagrams reveal that the AGN emission is concentrated in the inner 0.5 $R_e$ (effective radius) region of the galaxies, showing that the AGN classification is aperture dependent and that emission-line ratios have to be taken together with the H$\alpha$ equivalent width for proper activity classification. We present a composite "BPT+WHAN" diagram that produces a more comprehensive mapping of the gas excitation.Comment: Accepted for publication in MNRA

THE EFFECT OF INTERMITTENT HYPOXIC TRAINING UNDER OXIDATIVE STRESS PARAMETERS IN WISTAR RATS FED ON STANDARD AND HIGH FAT DIET

Considerando-se que dietas ricas em gordura levam ao estresse oxidativo, causando lesões nas células e que o treinamento hipóxico intermitente (THI) aumenta as defesas antioxidantes endógenas em diversas situações, o objetivo deste estudo foi avaliar o efeito do THI em parâmetros de estresse oxidativo e defesas antioxidantes em fígado de ratos Wistar alimentados com dieta rica em gordura e/ou dieta padrão. Ratos Wistar foram divididos em grupos alimentados com dieta padrão ou rica em gordura. Os grupos foram submetidos a hipóxia intermitente (HI), 15 minutos HI (14-11% O2) intercalados com cinco minutos de re-oxigenação ou sessões de normóxia (N) (21% O2), por um período de duas horas diárias durante 30 dias. Os ratos Wistar alimentados com dieta padrão, e submetidas a HI, apresentaram uma redução de 37,7% na concentração de substâncias reativas ao ácido tiobarbitúrico (TBARS) e aumento de 34,66% e 39,8% no conteúdo de superóxido dismutase (SOD) e catalase (CAT), respectivamente, em comparação com o seu controlo (normoxia). No grupo com dieta rica em gordura, não houve diferença estatística entre os subgrupos HI e N. Nossos dados, que demonstram que o THI possui efeito antioxidante no fígado de ratos Wistar, argumentam em favor do uso alternativo de protocolos de hipoxia intermitente no tratamento de determinadas patologias

Um novo m?todo para aloca??o de unidade em subamostras representativas baseado em covari?veis discretas.

Em estudos experimentais nos quais se deseja verificar a efic?cia de alguma interven??o, ? usual a presen?a de grupos que sofrer?o ou n?o estas interven??es para que compara??es a respeito de fatores relacionados a estas interven??es possam ser medidos. Para garantir que tais compara??es sejam v?lidas, ? necess?rias que os grupos apresentem caracter?sticas o mais semelhantes poss?vel entre si, definidas no in?cio do estudo. Este trabalho apresenta uma nova metodologia de divis?o, dado um conjunto de dados inicial, em k subamostras representativas em rela??o aos dados iniciais, com base em covari?veis que definem as caracter?sticas desta. Os resultados obtidos constatam que a metodologia de aleatoriza??o proposta apresenta resultados satisfat?rios, principalmente se comparados com a t?cnica tradicional de amostragem aleat?ria simples. As subamostras delineadas pelo m?todo apresentam um alto grau de similaridade com a amostra original, o que possibilitar? aos estudos experimentais deste trabalho uma redu??o no vi?s de sele??o, proporcionando resultados mais satisfat?rios.In experimental studies, like clinic trials, where one wants to verify the eficacy of some intervention, the presence of different groups that will suffer the or not the interventions, so one can make future comparisons. To waranty that the comparisons will be valid, it?s necessary that the groups shows the most similar characteristics among them and the original sample. This study brings a new methodology of division of an original sample in k representative sub-samples about the original sample, based in the covariates that defines the original sample characteristics. The results demonstrate that the proposed methodology shows very satisfatory results, mainly if compared to the traditional method, the random sampling. The sub-samples defined by the new method shows a high similarity with the original sample, which will made possible experimental studies with low selection bias and reliable results

Exacerbated inflammatory cellular immune response characteristics of HAM/TSP is observed in a large proportion of HTLV-I asymptomatic carriers

BACKGROUND: A small fraction of Human T cell Leukemia Virus type-1 (HTLV-I) infected subjects develop a severe form of myelopathy. It has been established that patients with HTLV-I associated myelopathy/tropical spastic paraparesis (HAM/TSP) show an exaggerated immune response when compared with the immunological response observed in HTLV-I asymptomatic carriers. In this study the immunological responses in HAM/TSP patients and in HTLV-I asymptomatic carriers were compared using several immunological assays to identify immunological markers associated with progression from infection to disease. METHODS: Immunoproliferation assays, cytokine levels of unstimulated cultures, and flow cytometry analysis were used to evaluate the studied groups. Nonparametric tests (Mann-Whitney U test and Wilcoxon matched-pairs signed ranks) were used to compare the difference between the groups. RESULTS: Although both groups showed great variability, HAM/TSP patients had higher spontaneous lymphoproliferation as well as higher IFN-γ levels in unstimulated supernatants when compared with asymptomatic carriers. Flow cytometry studies demonstrated a high frequency of inflammatory cytokine (IFN-γ and TNF-α) producing lymphocytes in HAM/TSP as compared to the asymptomatic group. This difference was accounted for mainly by an increase in CD8 cell production of these cytokines. Moreover, the HAM/TSP patients also expressed an increased frequency of CD28-/CD8+ T cells. Since forty percent of the asymptomatic carriers had spontaneous lymphoproliferation and IFN-γ production similar to HAM/TSP patients, IFN-γ levels were measured eight months after the first evaluation in some of these patients to observe if this was a transient or a persistent situation. No significant difference was observed between the means of IFN-γ levels in the first and second evaluation. CONCLUSIONS: The finding that a large proportion of HTLV-I carriers present similar immunological responses to those observed in HAM/TSP, strongly argues for further studies to evaluate these parameters as markers of HAM/TSP progression