Influence of channel aspect ratio on the onset of purely-elastic flow instabilities in three-dimensional planar cross-slots

In this work, we perform creeping-flow simulations of upper-convected Maxwell and simplified Phan-Thien-Tanner fluids to study the purely-elastic steady bifurcation and transition to time-dependent flow in three-dimensional planar cross-slots. By analysing the flow in geometries with aspect ratios ranging from the near Hele-Shaw flow like limit, up to the very deep, two-dimensional limit, we are able to characterize the mechanism of the cross-slot bifurcation with significant detail. We conclude that the bifurcation mechanism is similar to a buckling instability, by which fluid is redirected via paths of least resistance, resulting in the emergence of peripheral stagnation points, above and below the central stagnation point. The intake of matter at the centre via the inlet axis is thus reduced, being compensated by fluid flowing through low resistance corridors along the central vertical axis, above and below the central point. Furthermore, we propose and locally compute a modified Pakdel-McKinley criterion, thereby producing a scalar stability field and suggesting emergent peripheral stagnation points also indirectly contribute to the onset of time-dependent flow. (c) 2015 The Authors. Published by Elsevier B.V

A new viscoelastic benchmark flow: Stationary bifurcation in a cross-slot

AbstractIn this work we propose the cross-slot geometry as a candidate for a numerical benchmark flow problem for viscoelastic fluids. Extensive data of quantified accuracy is provided, obtained via Richardson extrapolation to the limit of infinite refinement using results for three different mesh resolutions, for the upper-convected Maxwell, Oldroyd-B and the linear form of the simplified Phan-Thien–Tanner constitutive models. Furthermore, we consider two types of flow geometry having either sharp or rounded corners, the latter with a radius of curvature equal to 5% of the channel’s width. We show that for all models the inertialess steady symmetric flow may undergo a bifurcation to a steady asymmetric configuration, followed by a second transition to time-dependent flow, which is in qualitative agreement with previous experimental observations for low Reynolds number flows. The critical Deborah number for both transitions is quantified and a set of standard parameters is proposed for benchmarking purposes

High Performance Liquid Chromatography Method for the Determination of Anethole in Rat Plasma

Purpose: To identify and quantify anethole in the essential oil of fruits of Illicium verum Hook (star anise) and in vivo in rat plasma using reverse-phase liquid chromatography.Methods: Anethole was identified in the essential oil of the fruits of Star anise and determined by gas chromatography-tandem mass spectrometry (GC-MS), nuclear magnetic resonance (NMR), ultraviolet visible spectrophotometry (UV-VIS). A simple, sensitive and validated high performance liguid chromatography (HPLC) technique with UV-VIS detection method was developed for the determination of the compound in rat plasma using: methanol-water (85:15, v/v) as mobile phase at a flow rate of 0.2 ml/min Hypersil ODS Thermo (150 mm x 2.1 mm x 3.0 μM) as column with wavelength detection at 259 nm.Results: GC determination showed that anethole in the essential oil of star anise exhibited a retention time of 21.02 min. The validation results for anethole in plasma were satisfactory, with coefficient of determination (R2) of 0.9945 and relative standard deviation of < 3 %. HPLC run time of 4 min with a retention time of 2.73 min was the faster method to determine anethole when compared to a previously reported method which had a run time of 15 min.Conclusion: Anethole in the essential oil of Illicium verum Hook can be identified and determined by GC-MS, NMR and UV-VIS, and a superior HPLC method has been developed for the determination of the compound in rat plasma.Keywords: Anethole, High performance liguid chromatography, Star anise, Essential oil, Rat plasma, Illicium verum Hook

GÊNEROS E SEXUALIDADES NA FORMAÇÃO DE DOCENTE: ANALISANDO SABERES A PARTIR DE OFICINAS PEDAGÓGICAS

O que pensam as estudantes de Pedagogia e Licenciaturas sobre os gêneros e as sexualidades? Quais são suas principais dúvidas sobre esses temas? Quais são as possibilidades de debater a diversidade de gênero e as sexualidades na formação docente? Nesse artigo, analisamos as experiências da aplicação da oficina “Corpo, gênero e sexualidade na escola”, realizada em três turmas, de duas universidades cariocas. Para isso, trazemos reflexões de materiais produzidos pelas alunas. Assim, pretendemos lançar algumas pistas sobre a construção de saberes em gêneros e sexualidades na formação docente.Palavras chave: Gênero. Sexualidade. Formação docente. Oficinas pedagógicas. GENDERS AND SEXUALITIES IN TEACHER TRAINING: ANALYZING KNOWLEDGE FROM PEDAGOGICAL WORKSHOPSWhat do Pedagogy and Undergraduate students think about genders and sexualities? What are your main doubts about these topics? What are the possibilities for discussing gender diversity and sexualities in teacher education? In this article, we analyze the experiences of applying the workshop “Body, gender and sexuality at school”, held in three classes, from two Rio de Janeiro universities. For that, we bring reflections of materials produced by the students. Thus, we intend to launch some clues about the construction of knowledge on gender and sexuality in teacher education.Keywords: Gender. Sexuality. Teacher training. Pedagogical workshops

Microfluidic systems for the analysis of the viscoelastic fluid flow phenomena in porous media

In this study, two microfluidic devices are proposed as simplified 1-D microfluidic analogues of a porous medium. The objectives are twofold: firstly to assess the usefulness of the microchannels to mimic the porous medium in a controlled and simplified manner, and secondly to obtain a better insight about the flow characteristics of viscoelastic fluids flowing through a packed bed. For these purposes, flow visualizations and pressure drop measurements are conducted with Newtonian and viscoelastic fluids. The 1-D microfluidic analogues of porous medium consisted of microchannels with a sequence of contractions/ expansions disposed in symmetric and asymmetric arrangements. The real porous medium is in reality, a complex combination of the two arrangements of particles simulated with the microchannels, which can be considered as limiting ideal configurations. The results show that both configurations are able to mimic well the pressure drop variation with flow rate for Newtonian fluids. However, due to the intrinsic differences in the deformation rate profiles associated with each microgeometry, the symmetric configuration is more suitable for studying the flow of viscoelastic fluids at low De values, while the asymmetric configuration provides better results at high De values. In this way, both microgeometries seem to be complementary and could be interesting tools to obtain a better insight about the flow of viscoelastic fluids through a porous medium. Such model systems could be very interesting to use in polymer-flood processes for enhanced oil recovery, for instance, as a tool for selecting the most suitable viscoelastic fluid to be used in a specific formation. The selection of the fluid properties of a detergent for cleaning oil contaminated soil, sand, and in general, any porous material, is another possible application

Population Genetics of Streptococcus dysgalactiae Subspecies equisimilis Reveals Widely Dispersed Clones and Extensive Recombination

Streptococcus dysgalactiae subspecies equisimilis (SDSE) is an emerging global pathogen that can colonize and infect humans. Although most SDSE isolates possess the Lancefield group G carbohydrate, a significant minority have the group C carbohydrate. Isolates are further sub-typed on the basis of differences within the emm gene. To gain a better understanding of their molecular epidemiology and evolutionary relationships, multilocus sequence typing (MLST) analysis was performed on SDSE isolates collected from Australia, Europe and North America.The 178 SDSE isolates, representing 37 emm types, segregate into 80 distinct sequence types (STs) that form 17 clonal complexes (CCs). Eight STs recovered from all three continents account for >50% of the isolates. Thus, a small number of STs are highly prevalent and have a wide geographic distribution. Both ST and CC strongly correlate with group carbohydrate. In contrast, eleven STs were associated with >1 emm type, suggestive of recombinational replacements involving the emm gene; furthermore, 35% of the emm types are associated with genetically distant STs. Data also reveal a history of extensive inter- and intra-species recombination involving the housekeeping genes used for MLST. Sequence analysis of single locus variants identified through goeBURST indicates that genetic change mediated by recombination occurred approximately 4.4 times more frequently than by point mutation.A few genetic lineages with an intercontinental distribution dominate among SDSE causing infections in humans. The distinction between group C and G isolates reflects recent evolution, and no long-term genetic isolation between them was found. Lateral gene transfer and recombination involving housekeeping genes and the emm gene are important mechanisms driving genetic variability in the SDSE population

Postmortem Analyses Unveil the Poor Efficacy of Decontamination, Anti-Inflammatory and Immunosuppressive Therapies in Paraquat Human Intoxications

studies resulting from human PQ poisonings have assessed the relationship of these therapeutic measures with PQ toxicokinetics and related histopathological lesions, these being the aims of the present study.For that purpose, during 2008, we collected human fluids and tissues from five forensic autopsies following fatal PQ poisonings. PQ levels were measured by gas chromatography-ion trap mass spectrometry. Structural inflammatory lesions were evaluated by histological and immunohistochemistry analysis. The samples of cardiac blood, urine, gastric and duodenal wall, liver, lung, kidney, heart and diaphragm, showed quantifiable levels of PQ even at 6 days post-intoxication. Structural analysis showed diffused necrotic areas, intense macrophage activation and leukocyte infiltration in all analyzed tissues. By immunohistochemistry it was possible to observe a strong nuclear factor kappa-B (NF-κB) activation and excessive collagen deposition.Considering the observed PQ levels in all analyzed tissues and the expressive inflammatory reaction that ultimately leads to fibrosis, we conclude that the therapeutic protocol usually performed needs to be reviewed, in order to increase the efficacy of PQ elimination from the body as well as to diminish the inflammatory process

Effects of intrauterine food restriction and long-term dietary supplementation with L-arginine on age-related changes in renal function and structure of rats

We have previously demonstrated that restricting intrauterine food by 50% in 3-mo-old rats produced lower nephron numbers and early-onset hypertension, the latter being normalized by L-arginine administration. in 18-mo-old rats, such restriction increased glomerulosclerosis. in this study, we expanded our investigation, evaluating functional, morphologic, and immunohistochemical parameters in intrauterine-food-restricted 18-mo-old rats, either receiving L-arginine (RA18) or not (R18). Age-matched, non-food-restricted controls were assigned to similar groups with L-arginine (CA18) and without (C18). After weaning, L-arginine was given daily for 17 mo. No functional or morphologic changes were observed in C IS rats. the R18 rats developed early-onset hypertension, which persisted throughout the observation period, as well its significant proteinuria from 12 mo on. in RA18 rats, L-arginine decreased both blood pressure levels and proteinuria, and glomerular diameter was si,significantly smaller than in R18 rats (115.63 +/- 2.2 versus 134.8 +/- 1.0 mu m, p < 0.05). However, in RA18 rats, glomerular filtration rate remained depressed. Although L-arginine prevented glomerulosclerosis (R18 = 14%, RA18 = 4%; p < 0.05), glomerular expression of fibronectin and desmin was still greater in RA18 rats than in controls. Our data show that, although L-arginine prevented hypertension and proteinuria, glomerular injury still occurred, suggesting that intrauterine food restriction may be one of the leading causes of impaired renal function in adult life.Universidade Federal de São Paulo, Dept Physiol, EPM, Dept Physiol, BR-04023900 São Paulo, BrazilUniversidade Federal de São Paulo, Dept Physiol, EPM, Dept Morphol,Embrol Div, BR-04023900 São Paulo, BrazilUniv São Paulo, Ribeirao Preto Sch Med, Dept Physiol & Biophys, Brookline, MA 02146 USAUniversidade Federal de São Paulo, Dept Physiol, EPM, Dept Physiol, BR-04023900 São Paulo, BrazilUniversidade Federal de São Paulo, Dept Physiol, EPM, Dept Morphol,Embrol Div, BR-04023900 São Paulo, BrazilWeb of Scienc

Outcomes of allogeneic stem cell transplantation among patients with acute myeloid leukemia presenting active disease: Experience of a single European Comprehensive Cancer Center

Introduction: Allogeneic hematopoietic stem cell transplantation (ASCT) represents a potentially curative approach for patients with relapsed or refractory acute myeloid leukemia (AML). We report the outcome of relapsed/refractory AML patients treated with ASCT.Method: A retrospective cohort from 1994 to 2013 that included 61 patients with diagnosis of relapsed/refractory AML. Outcomes of interest were transplant-related mortality (TRM), incidence of acute and chronic graft-versus-host disease (GVHD), relapse incidence, progression-free survival (PFS) and overall survival (OS). Statistical significance was set at p<0.05.Results: The median age was 61 years (range 1 to 65). The cumulative incidence of 90 days, 1 year, and 3 years TRM were 60%, 26.7%, and 13.3%, respectively (p< 0.001). The incidence of relapse was 21.7% at 1 year, 13% at 3 years, and 8.7% at 5 years. Median OS was estimated to be 8 months (95CI 3.266-12.734) and median PFS, 3 months (95CI 1.835-4.165).Conclusion: In our cohort, TRM in first years after ASCT remains considerable, but ASCT in this setting seems to be a good choice for AML patients with active disease. However, novel approaches are needed to reduce TRM and relapse in this set of patients