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It is well established that the aging heart exhibits left ventricular (LV) diastolic dysfunction and changes in mechanical properties, which are thought to be due to alterations in the extracellular matrix. We tested the hypothesis that the mechanical properties of cardiac myocytes significantly change with aging, which could contribute to the global(More)
The objective of this study was to test the hypothesis that the mechanism mediating left ventricular (LV) dysfunction in the aging rat heart involves, in part, changes in cardiac cytoskeletal components. Our results show that there were no significant differences in heart rate, LV pressure, or LV diameter between conscious, instrumented young [5.9 +/- 0.3(More)
Many microfluidic applications require the mixing of reagents, but efficient mixing in these laminar (i.e., low Reynolds number) systems is typically difficult. Instead of using complex geometries and/or relatively long channels, we demonstrate the merits of flow rate time dependency through periodic forcing. We illustrate the technique by studying mixing(More)
Fluid mixing in microchannels is needed for many applications ranging from bio-arrays to micro-reactors, but is typically difficult to achieve. A simple geometry micro-mixer is proposed based on the electro-hydrodynamic (EHD) force present when the fluids to be mixed have different electrical properties and are subjected to an electric field. The electrodes(More)
  • P Singh, N Aubry
  • 2005
The point dipole (PD) model is routinely used for estimating the dielectrophoretic (DEP) force acting on a particle placed in the nonuniform electric fields of dielectrophoresis devices, such as square cages. We show that if the particle size is much smaller than the dielectrophoretic cage size, the PD model accurately approximates the actual DEP force,(More)
The rapid mixing of reagents is a crucial step for on-chip chemical and biological analysis. It has been recently suggested that microfluidic mixing can be greatly enhanced by simply using time pulsing of the incoming flow rates of the two fluids to be mixed (Glasgow, I.; Aubry, N. Lab Chip 2003, 3, 114-120). This paper elaborates on the latter technique,(More)
In microfluidic devices the fluid can be manipulated either as continuous streams or droplets. The latter is particularly attractive as individual droplets can not only move but also split and fuse, thus offering great flexibility for applications such as laboratory-on-a-chip. We consider the transport of liquid drops immersed in a surrounding liquid by(More)
We experimentally study the transient clustering behavior of viable yeast cells in a dilute suspension suddenly subjected to a nonuniform alternating current (AC) electric field of a microelectrode device. The frequency of the applied electric field is varied to identify two distinct regimes of positive dielectrophoresis. In both regimes, the yeast cells(More)