Effect of extended surfaces on lauric acid melting process in annular cavities

The objective of the present work is to parametrically analyze the effect of extended surfaces’ proportion and positioning on the lauric acid melting process, in an annular cavity. In total 46 geometric configurations were studied, varying between 5 area ratios, 5 proportions, and 2 positions of the extended surface. Numerical simulations performed with the finite volume method were used to conduct the study. The numerical model, composed of the continuity, momentum conservation, and energy conservation equations, plus the enthalpy-porosity phase change model, was validated with experimental data from the literature. The Grid Convergence Index (GCI) was used to evaluate the computational mesh, resulting in an average index of 0.0026%. The results are presented in terms of liquid fraction vs Fourier, and Nusselt number vs. Fourier. Besides, velocity vectors, and streamlines, liquid fraction, and temperature fields, were presented, comparing different instants and geometric arrangements. For the analysis of the results, the melting time was considered as a performance indicator. The results revealed that: while there is solid PCM in the cavity's upper section, the melting rate in systems with horizontal extensions is 15% higher than systems with vertical extensions; when the extended surface thinness is increased, the overall melting time is reduced by more than 10% in vertical arrangements and less than 1.5% in horizontal arrangements; the total melting time is nearly 45% faster in systems with vertical extensions than in systems with horizontal extensions

Effect of non-Newtonian fluid rheology on an arterial bypass graft: A numerical investigation guided by constructal design

In post-operative scenarios of arterial graft surgeries to bypass coronary artery stenosis, fluid dynamics plays a crucial role. Problems such as intimal hyperplasia have been related to fluid dynamics and wall shear stresses near the graft junction. This study focused on the question of the use of Newtonian and non-Newtonian models to represent blood in this type of problem in order to capture important flow features, as well as an analysis of the performance of geometry from the view of Constructive Theory. The objective of this study was to investigate the effects rheology on the steady-state flow and on the performance of a system consisting of an idealized version of a partially obstructed coronary artery and bypass graft. The Constructal Design Method was employed with two degrees of freedom: the ratio be- tween bypass and artery diameters and the junction angle at the bypass inlet. The flow problem was solved numerically using the Finite Volume Method with blood modeled employing the Carreau equation for viscosity. The Computational Fluid Dynamics model associated with the Sparse Grid method generated eighteen response surfaces, each representing a severe stenosis degree of 75% for specific combinations of rheological parameters, dimensionless viscosity ratio, Carreau number and flow index at two distinct Reynolds numbers of 150 and 250. There was a considerable dependence of the pressure drop on rhe- ological parameters. For the two Reynolds numbers studied, the Newtonian case presented the lowest value of the dimensionless pressure drop, suggesting that the choice of applying Newtonian blood may underestimate the value of pressure drop in the system by about 12.4% ( Re = 150) and 7.8% ( Re = 250). Even so, results demonstrated that non-Newtonian rheological parameters did not influence either the shape of the response surfaces or the optimum bypass geometry, which consisted of a diameter ratio of 1 and junction angle of 30 °. However, the viscosity ratio and the flow index had the greatest im- pact on pressure drop, recirculation zones and wall shear stress. Rheological parameters also affected the recirculation zones downstream of stenosis, where intimal hyperplasia is more prevalent. Newto- nian and most non-Newtonian results had similar wall shear stresses, except for the non-Newtonian case with high viscosity ratio. In the view of Constructal Design, the geometry of best performance was in- dependent of the rheological model. However, rheology played an important role on pressure drop and flow dynamics, allowing the prediction of recirculation zones that were not captured by a Newtonian model

Clinical, magnetic resonance imaging, and histopathologic features of a hypoglossal malignant peripheral nerve sheath tumor in a maltese dog

Malignant tumours arising from peripheral nerves or displaying differentiation along the lines of the various elements of the nerve sheath are collectively referred to as MPNSTs. Histologically, in human MPNST, the malignant nature of these tumours is associated with an infiltrative and cellular proliferation of atypical, mitotically active spindle cells. Their predilection for sites varies with the species. In dogs the most common site for MPNST is the nerve roots or nerves of the brachial plexus, while the cranial nerve more frequently involved is the trigeminal nerve. In humans, hypoglossal peripheral nerve sheath tumours are rare, only few cases are described in literature; and the malignant forms are even exceptional. Fifty per cent of cases displayed both an intra- and extracrania component, and are referred as dumbbell-shaped tumours. To our knowledge this is the first case report an hypoglossal MPNST in a dog. In our case the tumour was dumbbell-shaped, with both intra-and extracranial components and associated with characteristic clinical signs of hypoglossal tumour. The malignant histological appearance of the lesion occurred without infiltrative growth

Immune response against adenovirus in acute upper respiratory tract infections in immunocompetent children

During acute upper respiratory tract infections (AURTIs) caused by Adenoviruses, the mix of severe clinical presentation, together with elevation of white blood cells (WBCs) and C-reactive protein (CRP), often mimicking bacterial infection, leads to an inappropriate use of antibiotics. We studied 23 immunocompetent children admitted to our Pediatric Emergency Unit with signs of acute Adenoviral AURTIs, aiming at better clarifying the biological background sustaining this clinical presentation. Infection etiology was tested with nasopharyngeal swabs, serology, and DNA-PCR. During fever peaks and subsequent recovery, we assessed WBC count with differential, CRP, procalcitonin, serum concentration of six inflammatory cytokines, and lymphocyte subset populations. Results: IL-6 and IL-8 were found elevated in the acute phase, whereas a significant decrease during recovery was found for IL-6 and IL-10. We highlighted an increase of B lymphocytes in the acute phase; conversely, during recovery, an increase in T regulatory cells was noted. Monocytes and leukocytes were found markedly elevated during fever peaks compared to convalescence. All patients recovered uneventfully. The composition of lymphocyte population subsets and serum alterations are the main drivers of an overprescribed antibiotic. Examination of hospital admissions and performance is needed in further investigations to rule out bacterial infections or inflammatory syndromes

Integrated transcriptomics and metabolomics reveal signatures of lipid metabolism dysregulation in HepaRG liver cells exposed to PCB 126.

Chemical pollutant exposure is a risk factor contributing to the growing epidemic of non-alcoholic fatty liver disease (NAFLD) affecting human populations that consume a western diet. Although it is recognized that intoxication by chemical pollutants can lead to NAFLD, there is limited information available regarding the mechanism by which typical environmental levels of exposure can contribute to the onset of this disease. Here, we describe the alterations in gene expression profiles and metabolite levels in the human HepaRG liver cell line, a validated model for cellular steatosis, exposed to the polychlorinated biphenyl (PCB) 126, one of the most potent chemical pollutants that can induce NAFLD. Sparse partial least squares classification of the molecular profiles revealed that exposure to PCB 126 provoked a decrease in polyunsaturated fatty acids as well as an increase in sphingolipid levels, concomitant with a decrease in the activity of genes involved in lipid metabolism. This was associated with an increased oxidative stress reflected by marked disturbances in taurine metabolism. A gene ontology analysis showed hallmarks of an activation of the AhR receptor by dioxin-like compounds. These changes in metabolome and transcriptome profiles were observed even at the lowest concentration (100 pM) of PCB 126 tested. A decrease in docosatrienoate levels was the most sensitive biomarker. Overall, our integrated multi-omics analysis provides mechanistic insight into how this class of chemical pollutant can cause NAFLD. Our study lays the foundation for the development of molecular signatures of toxic effects of chemicals causing fatty liver diseases to move away from a chemical risk assessment based on in vivo animal experiments

Numerical Study and Geometric Investigation of the Influence of Rectangular Baffles over the Mixture of Turbulent Flows into Stirred Tanks

The present work aims to define strategies for numerical simulation of the mixture of turbulent flows in a stirred tank with a low computational effort, and to investigate the influence of the geometry of four rectangular baffles on the problem of performance. Two computational models based on momentum source and sliding mesh are validated by comparison with experimental results from the literature. For both models, the time‐averaged conservation equations of mass, momentum and transport of the mixture are solved using the finite volume method (FVM) (FLUENT® v.14.5). The standard k–ε model is used for closure of turbulence. Concerning the geometrical investigation, constructal design is employed to define the search space, degrees of freedom and performance indicators of the problem. More precisely, seven configurations with different width/length (L/B) ratios for the rectangular baffles are studied and compared with an unbaffled case. The momentum source model leads to valid results and significantly reduces the computational effort in comparison with the sliding mesh model. Concerning the design, the results indicate that the case without baffles creates the highest magnitude of turbulence kinetic energy, but poorly distributes it along the domain. The best configuration, (L/B)o = 1.0, leads to a mixture performance nearly two times superior than the case without baffles

Glyphosate does not substitute for glycine in proteins of actively dividing mammalian cells

Glyphosate (N-phosphonomethyl glycine) and its commercial herbicide formulations have been shown to exert toxicity via various mechanisms. It has been asserted that glyphosate substitutes for glycine in polypeptide chains leading to protein misfolding and toxicity. However, as no direct evidence exists for glycine to glyphosate substitution in proteins, including in mammalian organisms, we tested this claim by conducting a proteomics analysis of MDA-MB-231 human breast cancer cells grown in the presence of 100 mg/L glyphosate for 6 days. Protein extracts from three treated and three untreated cell cultures were analysed as one TMT-6plex labelled sample, to highlight a specific pattern (+/+/+/−/−/−) of reporter intensities for peptides bearing true glyphosate treatment induced-post translational modifications as well as allowing an investigation of the total proteome

Demonstrator of Time Services based on European GNSS signals: the H2020 DEMETRA Project

During 2015-2016, a European Consortium of 15 partners from 8 different countries, developed the DEMETRA (DEMonstrator of EGNSS services based on Time Reference Architecture), a project funded by the European Union in the frame of the Horizon 2020 program. This project aims at developing and experimenting time dissemination services dedicated to specific users like traffic control, energy distribution, finance, telecommunication, and scientific institutions. Nine services have been developed. These services provide time dissemination with accuracy levels from millisecond to the sub-ns, and also additional services like certification, calibration, or integrity. Five of these services are based on the European GNSS. After a development phase (see PTTI 2016 presentation) the full DEMETRA system has been working during six months for demonstration. The paper will report about the experimentation results, showing performances and limits of the proposed time dissemination services, aiming to foster the exploitation of the European GNSS for timing applications