Flow Around a Spheroid in a Circular Tube

Smythe, W. R.

doi:10.1063/1.1711260

Cited by 72 publications

(47 citation statements)

References 5 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The relative height of a pulse ␦I͞I, where ␦I is the absolute pulse height and I is the baseline current value, depends on the relation of the diameter d of each colloid to the diameter D and length L of the pore (9,15,(27)(28)(29). For the values of d (Ϸ510 nm) and D (Ϸ900 nm) used here, this relation is described by:…”

Section: Discussionmentioning

confidence: 99%

Direct detection of antibody–antigen binding using an on-chip artificial pore

Saleh

Sohn

2003

Proc. Natl. Acad. Sci. U.S.A.

166

128

View full text Add to dashboard Cite

We demonstrate a rapid and highly sensitive all-electronic technique based on the resistive pulse method of particle sizing with a pore to detect the binding of unlabeled antibodies to the surface of latex colloids. Here, we use an on-chip pore to sense colloids derivatized with streptavidin and measure accurately their diameter increase on specific binding to several different types of antibodies. We show the sensitivity of this technique to the concentration of free antibody and that it can be used to perform immunoassays in both inhibition and sandwich configurations. Overall, our technique does not require labeling of the reactants and is performed rapidly by using very little solution, and the pore itself is fabricated quickly and inexpensively by using soft lithography. Finally, because this method relies only on the volume of bound ligand, it can be generally applied to detecting a wide range of ligand-receptor binding reactions.

show abstract

Section: Discussionmentioning

confidence: 99%

Direct detection of antibody–antigen binding using an on-chip artificial pore

Saleh

Sohn

2003

Proc. Natl. Acad. Sci. U.S.A.

166

128

View full text Add to dashboard Cite

show abstract

“…With these where u(u, v) is the fluid velocity vector, p is the pressure, dimensionless quantities, the vector forms of the conservation Eqs. [5] and [6] can be rewritten as Eqs. [12] through [14], in dimensionless form, using cylindrical coordinates (the asterisk has been omitted): tions are zero-slip along and across, and zero electric current flux across, the insulating wall.…”

Section: A the Flow Field In The Eszmentioning

confidence: 99%

“…The authors' previous study [17] on the motion of spherical particles in current-carrying liquid met- dence of particle trajectories on both the hydrodynamic and the electric fields. Therefore, for the application of the ESZ technique to liquid metal systems, a basic requirement is In addition to the volume dependence, the amplitude of that all particles to be measured should pass through the the resistance change also depends on the shape, [5] orienta-ESZ without being collected on the inner wall of the orifice, tion, [6,7] and radial position, [8] of the particle inside the oribesides the enhancement of the accuracy of particle size fice. Taking the effects of shape and orientation into account, measurement and particle discrimination.…”

Section: Introductionmentioning

confidence: 99%

Numerical studies of the motion of spheroidal particles flowing with liquid metals through an electric sensing zone

Guthrie

2000

Metall Mater Trans B

View full text Add to dashboard Cite

A mathematical model has been developed to describe the motion of variously shaped and oriented spheroids entrained in liquid metals passing through a cylindrical electric sensing zone (ESZ) developed for liquid metals cleanliness analyzer (LiMCA) systems. The fluid velocity field within the ESZ was obtained by solving the Navier-Stokes equations, while the trajectories of particles within the ESZ were calculated using the equations of motion for particles. These incorporate forces resulting from drag, added mass, history, and electromagnetic and fluid acceleration balanced against the time rate of changes in a particle momentum. The effects of particle or inclusion shape and orientation were taken into account by including correction factors for drag (R D ), added mass (M A ), history (B), and electromagnetic force (E M ). The numerical results show that particle trajectories are affected by the magnetic pressure number (R H ), the Reynolds number (Re), the blockage ratio (k), and the particlefluid density ratio (␥). In the axial direction, spheroidal particles travel further axially before hitting the wall as the fluid velocity (Re) increases. In the radial direction, the outwardly directed electromagnetic force on nonconducting spheroids increases with radial distance from the axis, with increasing electric current (R H ) and with increasing size (k) of the particle. At low electric currents (low R H ), the competition between the electromagnetic force and the radial fluid acceleration force in the entrance region is predicted to result in particle movements first toward the central axis, before outward motion toward the wall, but directly toward the wall at large currents (high R H ). Spheroidal particles with symmetric axes perpendicular to the transverse axis of the ESZ move faster toward the sidewall as the particle aspect ratio (E ) increases. The dominating increase in the added mass force over the increase in the electromagnetic force with decreasing E makes this effect much stronger for oblates (E Ͻ 1) than for prolates (E Ͼ 1). The stronger drag force on a prolate with its symmetric axis parallel to the axis of the ESZ makes it move slower toward the wall than a prolate with its axis of symmetry perpendicular to the axis of the ESZ. Low-inertia (low-␥) spheroidal particles move faster toward the sidewall than do heavier particles. This effect of ␥ is stronger for prolates than for oblates traversing with their symmetric axes perpendicular to the axis of the ESZ, owing to the decreased added mass effect as E increases, while the effect of ␥ becomes much stronger for a prolate traversing with its symmetric axis perpendicular rather than parallel to the axis of the ESZ, owing to its smaller added mass. The radial particle velocity when approaching the wall is predicted to decrease due to the wall effects. This model has been applied to the movement of spheroidal inclusions within the ESZ of a LiMCA system in molten aluminum, and it was proven from the theoretical point of view that LiMCA systems could be...

show abstract

“…Hydrodynamic focusing was utilized to minimize edge effects in the electric field and was similar in nature to the approach described by Spielman and Goren in 1968 (26) for analyzing plastic microspheres. Since spheroids grow to large volumes (e.g., 5 x lo7 pm3), the volume-to-orifice diameter is more critical when measuring spheroids than when sizing single cells (11,24,25). A 1000-pm diameter orifice was used in this study, but we plan to use a 2000-pm sapphire orifice with additional sheath flow in future studies to improve signal quality.…”

Section: Discussionmentioning

confidence: 99%

Correlation of the growth of chinese hamster V₂79‐171b multicellular spheroids with cytokinetic parameters

et al. 1980

View full text Add to dashboard Cite

The volumes of Chinese hamster V279-171b multicellular spheroids grown in spinner culture were measured and correlated to DNA distribution and cell volume distribution information. Spheroid growth curves were obtained over a 21-day period using both electronic cell volume measurements and microscope micrometer sizing. The spheroids were collected from the aperture tube after electronic sizing, and single cell suspensions were prepared via trypsinization. Saline-washed cells were then stained with mithramycin and analyzed as unfixed or ethanol-fixed cells for both cell volume and DNA fluorescence measurements. Spheroid growth was determined to have an initial 8-to 9-day rapid growth phase, and a Tumor growth and growth delay measurements as well as cell-cycle measurements have been widely used as tumor biology end points (8,21,23). A better understanding of tumor kinetics might result from detailed correlative information for tumor growth dynamics in relation to cell-cycle kinetic properties of subpopulations comprising the tumor.Multicellular spheroids are of intermediate complexity, between in uztro monolayer cultured cells and subclinical size in uiuo nodular tumors or early metastatic foci. Spheroids are comprised of heterogeneous subpopulations (6,7) and provide a useful cell system for studying growth dynamics by electronic volume (2) ( i e . , Coulter principle) and for monitoring the cytokinetic DNA distribution and cell volume distributions of cells which comprise the spheroids. To date, electronic cell volume, enumeration and sizing (2) of single mammalianPerformed under the auspices of the United States Department of Energy, with joint support from Grant 2258501 from the National Cancer Institute, Department of Health, Education, and Welfare.Presented at Automated Cytology VII, Asilomar, California, November 25-30, 1979. slow phase from 10 to 21 days. The single cell volume distributions of cells obtained from spheroids were dependent on spheroid volume and the relative proportions of small volume noncycling cells to large volume cycling cells comprising the spheroids were also dependent on spheroid volume. DNA distribution data and dual parameter DNA distribution cell volume contour patterns obtained for single cells dissociated from spheroids were closely related to the measured spheroid volume and revealed that the fraction of small, hypoxic Go-like cells was greatest in old, large spheroids.Key terms: Spheroids, cytokinetic, flow cytometry, DNA distributions, cell volume cells have been extensively used and the underlying theory described (1, 2, 12, 24, 25). Conventional Coulter-type apertures having 10-2000 pm diameter orifices are available for single cell and large particle sizing (14). Various reports have described the usefulness of measuring cell volume in relation to cell-cycle information separately (13,15,18,28) and in coincidence with other parameters (3, 12,19,22,27).In the present report, the growth of V279-171b Chinese hamster lung multicellular spheroids were studied and correlated...

show abstract

Flow Around a Spheroid in a Circular Tube

Cited by 72 publications

References 5 publications

Direct detection of antibody–antigen binding using an on-chip artificial pore

Direct detection of antibody–antigen binding using an on-chip artificial pore

Numerical studies of the motion of spheroidal particles flowing with liquid metals through an electric sensing zone

Correlation of the growth of chinese hamster V₂79‐171b multicellular spheroids with cytokinetic parameters

Contact Info

Product

Resources

About

Flow Around a Spheroid in a Circular Tube

Cited by 72 publications

References 5 publications

Direct detection of antibody–antigen binding using an on-chip artificial pore

Direct detection of antibody–antigen binding using an on-chip artificial pore

Numerical studies of the motion of spheroidal particles flowing with liquid metals through an electric sensing zone

Correlation of the growth of chinese hamster V279‐171b multicellular spheroids with cytokinetic parameters

Contact Info

Product

Resources

About

Correlation of the growth of chinese hamster V₂79‐171b multicellular spheroids with cytokinetic parameters