Erythrocyte as a link between basic and clinical research

© 2011 – IOS Press and the authorsWe review the major hemorheological experimental studies that show the erythrocyte aggregation as a link between basic and clinical research. The results of the clinical cross-sectional and longitudinal studies presented here will highlight the possible association between erythrocyte aggregation and plasma fibrinogen. Basic studies conducted in vitro are also mentioned as for its relevance in answering questions raised in clinical settings, as well as and in understanding the underlying influent factors in the erythrocyte tendency to aggregate and disaggregate.This work was supported by “Fundação para a Ciência e Tecnologia

Evidence that the degree of band 3 phosphorylation modulates human erythrocytes nitric oxide efflux – in vitro model of hyperfibrinogenemia

© 2011 – IOS Press and the authors. All rights reservedRecent evidence has shown that plasma fibrinogen, a major cardiovascular risk factor, interacts with the erythrocyte membrane and acts to influence blood flow via erythrocyte nitric oxide (NO) modulation. In the present pioneer in-vitro study, whole blood samples were harvested from healthy subjects and aliquots were incubated in the absence (control aliquots) and presence of fibrinogen at different degrees of band 3 phosphorylation, and the levels of NO, nitrite, nitrate and S-nitroglutathione (GSNO) were determined. Hyperfibrinogenemia interferes with erythrocyte NO mobilization without changing its efflux in a way that seems to be dependent of the degree of band 3 phosphorylation. In presence of higher fibrinogen concentrations the NO efflux is reinforced when band 3 is phosphorylated (p < 0.001). Higher levels of nitrite, nitrate and GSNO were documented (p < 0.05). However, the mechanisms by which fibrinogen signalling modulates erythrocyte function remain to be clarified and are currently under study. These conditions may be considered an approach to be followed in blood storage for transfusions.This study was supported by grants from the FCT - Fundação para a Ciência e a Tecnologia (project reference PTDC/SAU-OSM/73449/2006

Uniform approximation for the overlap caustic of a quantum state with its translations

The semiclassical Wigner function for a Bohr-quantized energy eigenstate is known to have a caustic along the corresponding classical closed phase space curve in the case of a single degree of freedom. Its Fourier transform, the semiclassical chord function, also has a caustic along the conjugate curve defined as the locus of diameters, i.e. the maximal chords of the original curve. If the latter is convex, so is its conjugate, resulting in a simple fold caustic. The uniform approximation through this caustic, that is here derived, describes the transition undergone by the overlap of the state with its translation, from an oscillatory regime for small chords, to evanescent overlaps, rising to a maximum near the caustic. The diameter-caustic for the Wigner function is also treated.Comment: 14 pages, 9 figure

Dithiothreitol revisited in red cells : a new head for an old hat

© 2010 – IOS Press and the authors. All rights reservedIn the present article the authors make an approach over the applications of dithiothreitol (DTT) in its different clinicallaboratory, potential and up-to-date sources. Dithiothreitol is a chemical reagent with a wide actuation spectrum not only from a laboratorial view but also from a therapeutic standpoint, more clinical and practical. DTT (i) is frequently used in a variety of experiences that involve proteins or peptides, protecting sulfhydryl groups from oxidation and reducing disulfide bonds between cysteines; (ii) is also used in the study of disulfide exchange reactions of protein disulfides; (iii) is able to keep glutathione in the reduced state; (iv) acts as an “antidote” enabling the activity of detoxification systems; (v) participates in cellular mechanisms such as vesiculation, cell morphology, signal transduction pathways (hormone-‘like’ role), etc.; (vi) can be used in the treatment approach of diseases like cystinosis or medical conditions resulting from ion or metal toxicity. In erythrocytes, there’s literature pointing that DTT may trigger changes on the normal discoid shape following metabolic depletion, and additionally modulate the exovesiculation kinetics as demonstrated by us. The present article dissects in detail recent findings in our Unit concerning the DTT influence on human erythrocytes

FLOW CHARACTERIZATION FROM A NACA AIR INTAKE ASSEMBLED IN A CANARD TYPE AIRCRAFT

omputational aerodynamics analyses of a NACA air intake assembled in a canard type aircraft is performed in this work. Semi-empirical calculation through the ESDU (Engineering Science Database Unit) preceded the CFD simulations to define the geometric size of the air intake as well to check its efficiency and drag estimation. The NACA air inlet was considered one of the best options available for implementing in a canard type aircraft since it reduces aerodynamic drag by avoiding protuberances in the fuselage. Numerical studies were performed with the air intake mounted in the aircraft's fuselage at operational flight conditions. These simulations were performed using Reynolds-averaged Navier-Stokes (RANS) and turbulence modeling by using the k-ω SST (Shear-Stress Transport). Data analyses were based on the air inlet efficiency, drag estimation and mainly flow characterization. The numerical results helped to characterize the flow in a canard type aircraft showing that the NACA air intake yielded satisfactory performance with low drag. The approach applied in this work was a partnership with the Brazilian Aircraft Factory (FABE) and Federal University of Uberlândia (UFU) to improve the design of a canard type aircraft. The CFD results have been corroborated by an empirical approach and with some experimental tests performed by the company, pointing towards the reliability of a very efficient design tool for application in industry

Micromorfologia aplicada a morfometria de agregados.

A morfometria geralmente é utilizada para análise grãos em pedologia, no entanto este trabalho teve como objetivo utilizar a técnica da micromorfologia para estudo de morfometria de agregados dos solos para que possa servir como subsídio a caracterização da estrutura do solo em escala micro. Foi realizada análise de 8 lâminas correspondente a diferentes classes de solos. Foram calculadas a porosidade e atributos morfométricos, como: área, perímetro, arredondamento, maior eixo e menor eixo utilizando o software Quantiporo. Com auxílio do Microsoft® Office Excel complementou-se os atributos alongamento e compacidade dos agregados. Em geral, os resultados de porosidade concordam com classe textural e estrutura de cada perfil, encontrando-se maior porosidade em solos mais argilosos e siltosos do que nos arenosos; isso devido a quantidade de microporos nesses solos. Encontraram-se maiores semelhanças dos atributos de solos nas classes de tamanho de agregados do que em relação as diferentes classes de solos. Mesmo sendo analisada uma parte muito pequena de solo para representar uma classe de solo, os resultados mostraram coerência, visto que, houve uma similaridade entre os perfis de mesma classe e também aqueles representando uma mesma profundidade (0-10 cm)

Efeito do encharcamento e de alturas de corte sobre a taxa de expansão foliar em plantas de Brachiaria brizantha cv. Marandu.

Objetivou-se de contribuir para o entendimento dos fatores que possam estar envolvidos na morte de capim-braquiarão (Brachiaria brizantha cv Marandu), através da análise de encharcamento. Segundo Dias-Filho (Informação pessoal), o excesso de umidade é um dos principais causadores deste fenômeno

The Role of Volunteered Geographic Information towards 3D Property Cadastral Systems (2): A Purpose Driven Web Application

VGI has not proved to be readily suitable to replace well-established accurate methods and technologies such as those of full standard cadastral surveys. Even so, VGI potentialities as relevant source of geospatial data have been widely acknowledged. As such, some authors have defended that VGI may in fact play an important role such as at a local cadastral jurisdiction level towards local spatial data infrastructures. As far as property cadastre is concerned, the full extent 3D complexity inside a property is in many instances only known to their occupants, thus making crowd sourcing perhaps the only economically feasible approach for its capture. While the crowd cannot be expected to conduct a full cadastral survey, it may be possible to ask them to indicate at least the location of complex 3D situations and thus to facilitate local authorities’ understanding of the extent of some cadastral issues. As such, it was argued in our previous work that geoinformation from the crowd might in fact be taken into account as an interim step before a full surveyed 3D cadastre is eventually achieved. As such, possible room for VGI in the context of 3D cadastre was discussed, and a hierarchical framework of levels of data acquisition to be used at local cadastral jurisdiction level was proposed. Such framework is revisited in this paper.Given context above, this paper focuses primarily on two aspects. Firstly, to review technical requirements of the official cadastral process in Portugal in order to identify which sorts of cadastral data are likely to be acquirable/not acquirable through VGI. Secondly, to design and to implement the prototype of a web-based application (IGV3Dcad) envisaged for general public usage to flag different land and property ownership situations. Having information about the extent of the 2D/3D issue is also fundamental to making a decision as to whether a 3D cadastral approach is actually needed and hence to further invest resources in even more expensive 3D survey