Surface tension driven flow of blood in a rectangular microfluidic channel: Effect of erythrocyte aggregation

Microfluidic platforms have increasingly been explored for in vitro blood diagnostics and for studying complex microvascular processes. The perfusion of blood in such devices is typically achieved through pressure driven set-ups. Surface tension driven blood flow provides an alternative flow delivery option, and various studies in the literature have examined the behaviour of blood flow in such fluidic devices. In such flows, the influence of red blood cell (RBC) aggregation, the phenomenon majorly responsible for the non-Newtonian nature of blood, requires particular attention. In the present work, we examine differences in the surface tension driven flow of aggregating, non-aggregating RBC, and Newtonian suspensions, in a rectangular micro channel. The velocity fields were obtained using microPIV techniques. The analytical solution for blood velocity in the channel is developed utilising the power law model for blood viscosity. The results showed that RBC aggregation has an impact at the late stages of the flow, observed mainly in the bluntness of the velocity profiles. At the initial stages of the flow the shearing conditions are found moderately elevated, preventing intense RBC aggregate formation. As the flow decelerates in the channel RBC aggregation increases, affecting the flow characteristics

Levantamento e caracterização morfocultural de rizobactérias isoladas a partir de hortaliças cultivadas em sistema orgânico de produção.

bitstream/item/76436/1/bot050-092013.pd

Produção e vigor de clones de limeira ácida 'Tahiti' no Recôncavo baiano.

A lima ácida 'Tahiti' [Citrus latifolia (Yu. Tanaka) Tanaka] é conhecida e comercializada no mercado brasileiro como limão, razão pela qual também é chamada de limão 'Tahiti'. O Brasil, com produção de aproximadamente 44 mil toneladas anuais, ocupa o quarto lugar na produção mundial de limões, superado apenas pelo México, Índia e China (FAO, 2010). No Brasil a cultura do 'Tahiti' está baseada, praticamente, em duas seleções, o 'IAC-5' ou 'Peruano' e o 'Quebra-galho', e em apenas um porta-enxerto, o limoeiro 'Cravo' (C. limonia Osbeck) (FIGUEIREDO et al., 1996). Essa combinação copa/porta-enxerto possui reduzida vida útil, devido à sua grande suscetibilidade à gomose de Phytophthora spp., doença fúngica de ocorrência generalizada no país, e à contaminação por viroides, caso da seleção 'Quebra-galho' (FIGUEIREDO et al., 1991). A concentração do uso desses clones, aliada a fatores genéticos, como o relativamente grande tamanho de copa, fatores bióticos, suscetibilidade a fungos e viroides, notadamente, e fatores abióticos, como estresse hídrico, tem reduzido a eficiência de produção da limeira ácida 'Tahiti' nos pomares brasileiros. Este trabalho objetivou avaliar o desenvolvimento vegetativo e a produtividade de clones de 'Tahiti' nas condições climáticas de Cruz das Almas, Recôncavo baiano.pdf 119

Time-Dependent Variational Analysis of Josephson Oscillations in a Two-component Bose-Einstein Condensate

The dynamics of Josephson-like oscillations between two coupled Bose-Einstein condensates is studied using the time-dependent variational method. We suppose that the quantum state of the condensates is a gaussian wave-packet which can translate and perform breathing shape oscillations. Under this hypotheses we study the influence of these degrees of freedom on the tunneling dynamics by comparing the full-model with one where these degrees of freedom are ``frozen'' at its equilibrium values. The result of our calculation shows that when the traps are not displaced the two models agree, whereas when they are, the models differ considerably, the former being now closer to its linear approximation.Comment: 10 pages, 2 figure

Herding model and 1/f noise

We provide evidence that for some values of the parameters a simple agent based model, describing herding behavior, yields signals with 1/f power spectral density. We derive a non-linear stochastic differential equation for the ratio of number of agents and show, that it has the form proposed earlier for modeling of 1/f^beta noise with different exponents beta. The non-linear terms in the transition probabilities, quantifying the herding behavior, are crucial to the appearance of 1/f noise. Thus, the herding dynamics can be seen as a microscopic explanation of the proposed non-linear stochastic differential equations generating signals with 1/f^beta spectrum. We also consider the possible feedback of macroscopic state on microscopic transition probabilities strengthening the non-linearity of equations and providing more opportunities in the modeling of processes exhibiting power-law statistics

Desempenho de genótipos de mandioca em um Argissolo eutrófico na região sudoeste da Amazônia.

Objetivou-se com esse trabalho avaliar diferentes genótipos de mandioca quanto ao desempenho agronômico e industrial para a região sudoeste amazônica, em Rondônia

Resistivity study of the pseudogap phase for (Hg,Re) - 1223 superconductors

The pseudogap phase above the critical temperature of high $T_{c}$ superconductors (HTSC) presents different energy scales and it is currently a matter of intense study. The complexity of the HTSC normal state requires very accurate measurements with the purpose of distinguishing different types of phenomena. Here we have performed systematically studies through electrical resistivity ($\rho$) measurements by several different current densities in order to obtain an optimal current for each sample. This approach allows to determine reliable values of the pseudogap temperature $T^{*}(n)$, the layer coupling temperature between the superconductor layers $T_{LD}(n)$, the fluctuation temperature $T_{scf}(n)$ and the critical temperature $T_{c}(n)$ as function of the doping $n$. The interpretation of these different temperature scales allows to characterize possible scenarios for the (Hg,Re) - 1223 normal state. This method, described in detail here, and used to derive the (Hg,Re)-1223 phase diagram is general and can be applied to any HTSC.Comment: 31 pages, 12 figures, Latex; 25 pages, LaTeX; 11 figures; rewrited section II and III; added 18 reference; rewrited title, added discussion sectio

Emergência de genótipos de citros com potencial de uso como porta-enxertos.

A diversificação de porta-enxertos é uma realidade da citricultura brasileira face aos inúmeros e recorrentes problemas fitossanitários da cultura. O principal porta-enxerto utilizado, o limoeiro ?Cravo? (Citrus limonia Osbeck), é suscetível a doenças como morte súbita dos citros (MSC), gomose de Phytophthora spp. e declínio dos citros. Neste contexto, porta-enxertos alternativos vêm sendo avaliados, incluindo híbridos obtidos ou selecionados pelo Programa de Melhoramento Genético de Citros da Embrapa Mandioca e Fruticultura - PMG Citros