Computational fluid dynamics simulations of blood flow regularized by 3D phase contrast MRI

Abstract Background Phase contrast magnetic resonance imaging (PC-MRI) is used clinically for quantitative assessment of cardiovascular flow and function, as it is capable of providing directly-measured 3D velocity maps. Alternatively, vascular flow can be estimated from model-based computation fluid dynamics (CFD) calculations. CFD provides arbitrarily high resolution, but its accuracy hinges on model assumptions, while velocity fields measured with PC-MRI generally do not satisfy the equations of fluid dynamics, provide limited resolution, and suffer from partial volume effects. The purpose of this study is to develop a proof-of-concept numerical procedure for constructing a simulated flow field that is influenced by both direct PC-MRI measurements and a fluid physics model, thereby taking advantage of both the accuracy of PC-MRI and the high spatial resolution of CFD. The use of the proposed approach in regularizing 3D flow fields is evaluated. Methods The proposed algorithm incorporates both a Newtonian fluid physics model and a linear PC-MRI signal model. The model equations are solved numerically using a modified CFD algorithm. The numerical solution corresponds to the optimal solution of a generalized Tikhonov regularization, which provides a flow field that satisfies the flow physics equations, while being close enough to the measured PC-MRI velocity profile. The feasibility of the proposed approach is demonstrated on data from the carotid bifurcation of one healthy volunteer, and also from a pulsatile carotid flow phantom. Results The proposed solver produces flow fields that are in better agreement with direct PC-MRI measurements than CFD alone, and converges faster, while closely satisfying the fluid dynamics equations. For the implementation that provided the best results, the signal-to-error ratio (with respect to the PC-MRI measurements) in the phantom experiment was 6.56 dB higher than that of conventional CFD; in the in vivo experiment, it was 2.15 dB higher. Conclusions The proposed approach allows partial or complete measurements to be incorporated into a modified CFD solver, for improving the accuracy of the resulting flow fields estimates. This can be used for reducing scan time, increasing the spatial resolution, and/or denoising the PC-MRI measurements.http://deepblue.lib.umich.edu/bitstream/2027.42/116061/1/12938_2015_Article_104.pd

Design, synthesis and the effect of 1,2,3-triazole sialylmimetic neoglycoconjugates on Trypanosoma cruzi and its cell surface trans-sialidase

This work describes the synthesis of a series of sialylmimetic neoglycoconjugates represented by 1,4-disubstituted 1,2,3-triazole-sialic acid derivatives containing galactose modified at either C-1 or C-6 positions, glucose or gulose at C-3 position, and by the amino acid derivative 1,2,3-triazole fused threonine-3-O-galactose as potential TcTS inhibitors and anti-trypanosomal agents. This series was obtained by Cu(I)-catalysed azide-alkyne cycloaddition reaction ('click chemistry') between the azido-functionalized sugars 1-N(3)-Gal (commercial), 6-N(3)-Gal, 3-N(3)-Glc and 3-N(3)-Gul with the corresponding alkyne-based 2-propynyl-sialic acid, as well as by click chemistry reaction between the amino acid N(3)-ThrOBn with 3-O-propynyl-GalOMe. the 1,2,3-triazole linked sialic acid-6-O-galactose and the sialic acid-galactopyranoside showed high Trypanosoma cruzi trans-sialidase (TcTS) inhibitory activity at 1.0 mM (approx. 90%), whilst only the former displayed relevant trypanocidal activity (IC(50) 260 mu M). These results highlight the 1,2,3-triazole linked sialic acid-6-O-galactose as a prototype for further design of new neoglycoconjugates against Chagas' disease. (C) 2011 Elsevier B.V. All rights reserved.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)USP, Fac Ciencias Farmaceut Ribeirao Preto, BR-14040903 Ribeirao Preto, SP, BrazilUSP, Fac Med Ribeirao Preto, BR-14049900 Ribeirao Preto, SP, BrazilUniversidade Federal de São Paulo, Dept Microbiol Immunol & Parasitol, BR-04023062 São Paulo, BrazilUniversidade Federal de São Paulo, Dept Microbiol Immunol & Parasitol, BR-04023062 São Paulo, BrazilWeb of Scienc

The Genus Caesalpinia L. (Caesalpiniaceae): Phytochemical and Pharmacological Characteristics

The genus Caesalpinia (Caesalpiniaceae) has more than 500 species, many of which have not yet been investigated for potential pharmacological activity. Several classes of chemical compounds, such as flavonoids, diterpenes, and steroids, have been isolated from various species of the genus Caesalpinia. It has been reported in the literature that these species exhibit a wide range of pharmacological properties, including antiulcer, anticancer, antidiabetic, anti-inflammatory, antimicrobial, and antirheumatic activities that have proven to be efficacious in ethnomedicinal practices. in this review we present chemical and pharmacological data from recent phytochemical studies on various plants of the genus Caesalpinia.Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Fundação de Amparo à Pesquisa do Estado de Minas Gerais (FAPEMIG)Univ Fed Alfenas, Inst Chem, BR-37130000 Alfenas, MG, BrazilUniversidade Federal de São Paulo, Inst Environm Chem & Pharmaceut Sci, BR-09972 Diadema, SP, BrazilUniversidade Federal de São Paulo, Inst Environm Chem & Pharmaceut Sci, BR-09972 Diadema, SP, BrazilWeb of Scienc

Arthrospira (Spirulina) platensis cultivation in tubular photobioreactor: Use of no-cost CO2 from ethanol fermentation

The present study aimed at evaluating the production of Arthrospira platensis in tubular photobioreactor using CO2 from ethanol fermentation. The results of these cultivations were compared to those obtained using CO2 from cylinder at different protocols of simultaneous ammonium sulfate and sodium nitrate feeding. Maximum cell concentration (X-m), cell productivity (P-x), nitrogen-to-cell conversion factor (Y-X/N), and biomass composition (total lipids and proteins) were selected as responses and evaluated by analysis of variance. The source of CO2 did not exert any significant statistical influence on these responses, which means that the flue gas from ethanol fermentation could successfully be used as a carbon source as well as to control the medium pH, thus contributing to reduce the greenhouse effect. The results taken as a whole demonstrated that the best combination of responses mean values (X-m = 4.543 g L-1; P-x = 0.460 g L-1 d(-1); Y-X/N = 15.6 g g(-1); total lipids = 8.39%; total proteins = 18.7%) was obtained using as nitrogen source a mixture of 25% NaNO3 and 75% (NH4)(2)SO4, both expressed as nitrogen. (C) 2011 Elsevier Ltd. All rights reserved.CAPES (Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior) [0252/10-7]Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior (CAPES

Compression of Surface Electromyographic Signals Using Two-Dimensional Techniques

Non

Antiproliferative activity of flavonoids from croton Sphaerogynus baill. (euphorbiaceae)

Croton sphaerogynus is a shrub from the Atlantic Rain Forest in southeastern Brazil. A lyophilized crude EtOH extract from leaves of C. sphaerogynus, obtained by maceration at room temperature (seven days), was suspended in methanol and partitioned with hexane. The purified MeOH phase was fractionated over Sephadex LH-20 yielding five fractions (F1-F5) containing flavonoids, as characterized by HPLC-DAD and HPLC-MS analyses. The antiproliferative activity of the crude EtOH extract, MeOH and hexane phases, and fractions F1-F5 was evaluated on in vitro cell lines NCI-H460 (nonsmall cell lung), MCF-7 (breast cancer), and U251 (glioma). The MeOH phase showed activity (mean log GI(50) 0.54) higher than the hexane phase and EtOH extract (mean log GI(50) 1.13 and 1.19, resp.). F1 exhibited activity against NCI-H460 (nonsmall cell lung) (GI(50) 1.2 mu g/mL), which could be accounted for the presence of flavonoids and/or diterpenes. F4 showed moderate activity (mean log GI(50) 1.05), while F5 showed weak activity (mean log GI(50) 1.36). It is suggested that the antiproliferative activity of the crude EtOH extract and MeOH phase is accounted for a synergistic combination of flavonoids and diterpenes2015COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPESFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESPsem informação2012/10079-