Starch analysis using hydrodynamic chromatography with a mixed-bed particle column

Dias, Ricardo P.; Fernandes, Carla S.; Мота, М.; Teixeira, J. A.; Yelshin, Alexander

doi:10.1016/j.carbpol.2008.05.001

Cited by 25 publications

(12 citation statements)

References 36 publications

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“…[37][38][39][40] The boundary conditions were established in order to reproduce the experimental conditions-a constant flow rate was imposed in the inlet of the microchannel -3.0 Â 10 À12 m 3 /sand no-slip at the walls of the channel was assumed.…”

Section: à4mentioning

confidence: 99%

Asymmetry of red blood cell motions in a microchannel with a diverging and converging bifurcation

et al. 2011

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In microcirculation, red blood cells (RBCs) flowing through bifurcations may deform considerably due to combination of different phenomena that happen at the micro-scale level, such as: attraction effect, high shear, and extensional stress, all of which may influence the rheological properties and flow behavior of blood. Thus, it is important to investigate in detail the behavior of blood flow occurring at both bifurcations and confluences. In the present paper, by using a micro-PTV system, we investigated the variations of velocity profiles of two working fluids flowing through diverging and converging bifurcations, human red blood cells suspended in dextran 40 with about 14% of hematocrit level (14 Hct) and pure water seeded with fluorescent trace particles. All the measurements were performed in the center plane of rectangular microchannels using a constant flow rate of about 3.0 Â 10 À12 m 3 /s. Moreover, the experimental data was compared with numerical results obtained for Newtonian incompressible fluid. The behavior of RBCs was asymmetric at the divergent and convergent side of the geometry, whereas the velocities of tracer particles suspended in pure water were symmetric and well described by numerical simulation. The formation of a red cell-depleted zone immediately downstream of the apex of the converging bifurcation was observed and its effect on velocity profiles of RBCs flow has been investigated. Conversely, a cell-depleted region was not formed around the apex of the diverging bifurcation and as a result the adhesion of RBCs to the wall surface was enhanced in this region.

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Section: à4mentioning

confidence: 99%

Asymmetry of red blood cell motions in a microchannel with a diverging and converging bifurcation

et al. 2011

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“…Pullulan is a flexible random coil exopolysaccharide [41] and the R g -Mw relationship is The packed bed reported in Fig. (3) was used by Dias [20] and Dias et al [38] to separate amylose and amylopectin -by PCHDC -present in different commercial starches (gifts from National Starch & Chemical). The large molecules of amylopectin [42][43][44][45][46][47][48][49][50] eluted first and the resolution was similar to that obtained with size exclusion chromatography.…”

Section: Separation Mechanismsmentioning

confidence: 99%

“…HDC separation mechanism. The cylindrical capillary has a radius R and u(r) represents the local velocity for a stream line at a radial position r. The solvent and the mobile phase was water, the column had dimensions 200 4.6 mm ID and was packed with a mixture of glass spheres (65% with diameter 5 μm and 35% with diameter 19 μm), the average particle size [35][36][37][38][39][40] being 9.6 μm, = 0.316 and, therefore, the average pore radius, R, being 1.478 μm. Pullulan is a flexible random coil exopolysaccharide [41] and the R g -Mw relationship is The packed bed reported in Fig.…”

Section: Separation Mechanismsmentioning

confidence: 99%

Size Fractionation by Slalom Chromatography and Hydrodynamic Chromatography

Dias¹

2008

ENG

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Hydrodynamic chromatography, also called separation by flow, is based on the use of the parabolic flow profile occurring in open capillaries or in the pores from a column filled with non-porous particles. The hydrodynamic chromatography separation medium, if any, is much simpler than that from size exclusion chromatography (porous particles), the former technique being used in the size-fractionation of many colloids and macromolecules. The transition between hydrodynamic chromatography (obtained using low flow rates) and slalom chromatography (obtained using high flow rates) was reported in studies related with the migration behaviour of proteins, plasmid DNAs and double stranded DNAs. Slalom chromatography is mainly applied in the size-fractionation of large double stranded DNA fragments and may compete with electrophoretic techniques. In the present paper it is discussed the main patents, applications, advantages and drawbacks related to hydrodynamic chromatography and slalom chromatography, as well as some strategies that may improve the performance of these simple size-fractionation techniques.

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“…Figures 8 and 9 suggest that the RBCs velocities close to the microchannel wall are higher than that obtained with the numerical models since slip at the walls of the channel was assumed to be non-existent in the latter case. It is well know, in microcirculation and other areas [4,5,13,20,28,32], that RCBs, macromolecules, colloids, etc., are excluded from the region of the channel with low velocity and this may explain the observed differences.…”

Section: Resultsmentioning

confidence: 99%

“…For the velocity field, the modification on each node between two consecutive iterations is compared to the value of the velocity at the current iteration. In the present work, the convergence value was set to 10 4 , since this value is appropriate for the studied problem [5,[8][9][10]. The boundary conditions were established in order to reproduce the experimental conditions.…”

Section: Simulation Methodsmentioning

confidence: 99%

Microscale Flow Dynamics of Red Blood Cells in Microchannels: An Experimental and Numerical Analysis

Lima

Nakamura

Omori

et al.

Advances in Computational Vision and Medical Image Processing

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The book collects the state-of-the-art research, methods and new trends on the subject of computational vision and medical image processing contributing to the development of these knowledge areas. PrefaceNowadays, computational methodologies of signal processing and imaging analysis for 2D, 3D and even 4D data are commonly used for various applications in society. For example, Computational Vision systems are progressively used for surveillance tasks, traffic analysis, recognition process, inspection purposes, human-machine interfaces, 3D vision and deformation analysis.One of the main characteristics of the Computational Vision domain is its intermultidisciplinary nature. In fact, in this domain, methodologies of several other fundamental sciences, such as Informatics, Mathematics, Statistics, Psychology, Mechanics and Physics are regularly used. Besides this inter-multidisciplinary characteristic, one of the main rationale that promotes the continuous effort being made in this area of human knowledge is the number of applications in the medical area. For instance, statistical or physical procedures on medical images can be used in order to model the represented structures. This modelling can have different goals, for example: shape reconstruction, segmentation, registration, behavioural interpretation and simulation, motion and deformation analysis, virtual reality, computer-assisted therapy or tissue characterization.The main objective of the ECCOMAS Thematic Conferences on Computational Vision and Medical Image Processing (VIPimage) is to promote a comprehensive forum for discussion on the recent advances in the related fields and try to identify areas of potential collaboration between researchers of different sciences.This book contains the extended versions of nineteen papers selected from works presented at the second ECCOMAS thematic conference on Computational Vision and Medical Image processing (VIPimage 2009), which was held at the Engineering Faculty of the University of Porto, Portugal. It gathers together the state-of-the-art on the subject of Computational Vision and Medical Image processing contributing to the development of these knowledge areas and showing new trends in these fields.The Editors would like to take this opportunity to thank to the European Community on Computational Methods in Applied Sciences, the Abstract The blood flow dynamics in microcirculation depends strongly on the microvascular networks composed with short irregular vessel segments which are linked by numerous bifurcations. This paper presents the application of a confocal micro-PTV system to track RBCs through a rectangular polydimethysiloxane (PDMS) microchannel with a bifurcation. By using a confocal micro-PTV system, we have measured the effect of bifurcation on the flow behaviour of both fluorescent particles diluted in pure water and RBCs in concentrated suspensions. After performing simulations with the commercial finite element software package POLYFLOW R , some experimental results were compared with the nume...

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Starch analysis using hydrodynamic chromatography with a mixed-bed particle column

Cited by 25 publications

References 36 publications

Asymmetry of red blood cell motions in a microchannel with a diverging and converging bifurcation

Asymmetry of red blood cell motions in a microchannel with a diverging and converging bifurcation

Size Fractionation by Slalom Chromatography and Hydrodynamic Chromatography

Microscale Flow Dynamics of Red Blood Cells in Microchannels: An Experimental and Numerical Analysis

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