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Search Publications by: David J. Ross (Fed)

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Displaying 26 - 50 of 54

Counter-Flow Gradient Electrofocusing

February 1, 2007
Author(s)
Jonathan G. Shackman, David J. Ross
Counter-flow gradient electrofocusing methods are methods whereby a combination of electrophoresis and a bulk solution counter-flow is used to accumulate or focus analytes at stationary points along a separation column. This review first describes the

Scanning Temperature Gradient Focusing

August 2, 2006
Author(s)
S J. Hoebel, K M. Balss, Barbara J. Jones, C Malliaris, Matt S. Munson, Wyatt N. Vreeland, David J. Ross
Temperature gradient focusing (TGF) is a recently developed technique for the simultaneous concentration and electrophoretic separation of ionic analytes in microfluidic channels. One drawback to TGF as it has previously been described is the limited peak

Micellar Affinity Gradient Focusing

February 25, 2004
Author(s)
K M. Balss, P B. Howell, David J. Ross
This report describes a novel method for the concentration and separation of neutral and/or hydrophobic analytes based on a combination of the analytes partitioning into a micellar phase and their electrophoretic mobility. This method of simultaneous

Chiral Separations by Temperature Gradient Focusing

February 1, 2004
Author(s)
K M. Balss, Wyatt N. Vreeland, Karen W. Phinney, Michael J. Tarlov, David J. Ross
Temperature gradient focusing (TGF) involves application of a temperature gradient across a microchannel or capillary. With an appropriate buffer, the temperature gradient creates a gradient in both the electric field and the electrophoretic velocity

Elastic Flow Instability, Curved Streamlines and Mixing in Microfluidic Flows

February 1, 2004
Author(s)
Jai A. Pathak, David J. Ross, Kalman D. Migler
Flow instabilities are well known to occur in macroscopic flows when elastic fluids flow along curved streamlines. In this work we use flow visualization to study the mechanism underlying a purely elastic flow instability for Poiseuille flow in a micro (m)

Fluorescence Thermometry in Microfluidics

September 29, 2003
Author(s)
David J. Ross, Laurie E. Locascio
Two techniques are described for the measurement of fluid temperatures in microfluidic systems based on temperature-dependent fluorescence. In the first technique, a single, strongly temperature-dependent fluorophore, rhodamine B, is used as the basis for

Effect of Caged Fluorescent Dye on the Electroosmotic Mobility in Microchannels

March 1, 2003
Author(s)
David J. Ross, Laurie E. Locascio
We report on measurements of electroosmotic mobility in polymer microchannels and silica capillaries with and without the addition of a caged fluorescein dye to the buffer. For PMMA microchannels, the mobility was found to increase from (2.6 0.1) 10-4 cm2

Microfluidic Temperature Gradient Focusing

June 1, 2002
Author(s)
David J. Ross, Laurie E. Locascio
A new technique is described for the concentration and separation of ionic species in a microchannels. Concentration is achieved by balancing the electrophoretic velocity of an analyte against the bulk flow of solution in the presence of a temperature

Crossover from First-Order to Critical Wetting in Methanol on Alkanes

May 20, 2002
Author(s)
J O. Indekeu, A I. Posazhennikova, David J. Ross, D Bonn, J Meunier
A mean-field theory is presented which describes the basic observations of recent experiments revealing rich wetting behaviour of n-alkane/methanol mixtures at the liquid-vapour interface. The theory is based on a microscopic lattice-gas model from which a

Immobilization of DNA Hydrogel Plugs in Microfluidic Channels

March 15, 2002
Author(s)
K G. Olsen, David J. Ross, Michael J. Tarlov
Acrylamide-modified DNA probes are immobilized in polycarbonate microfluidic channels via photopolymerization in a polyacrylamide matrix. The resulting polymeric, hydrogel plugs are porous under electrophoretic conditions and hybridize with fluorescently

DNA Hydrogel Plugs Immobilized in Microfluidic Channels with Improved Stability

February 28, 2002
Author(s)
Rebecca A. Zangmeister, K G. Olsen, David J. Ross, Michael J. Tarlov
It has been previously demonstrated that DNA, modified on the 5' end with an acrylic acid group, can be incorporated into a polyacrylamide hydrogel matrix. These types of DNA containing gels have recently been immobilized in plastic microfluidic channels

Crossover From First-Order to Critical Wetting: Short-Range Tricritical Wetting

October 22, 2001
Author(s)
David J. Ross, D Bonn, A I. Posazhennikova, J O. Indekeu, J Meunier
We study wetting in liquid mixtures of methanol and the n-alkanes. Mixing alkanes of different chain lengths, we can examine the crossover between critical (continuous) and first-order (discontinuous) wetting transitions. Measurements of the film thickness

Temperature Measurement and Control in Microfluidic Systems

October 1, 2001
Author(s)
David J. Ross, Michael Gaitan, Laurie E. Locascio
We describe a technique for the measurement of fluid temperatures in microfluidic systems based on temperature-dependent fluorescence. The technique is easy to implement with a standard fluorescence microscope and CCD camera. The efficiency of the method