Sample dispersion in isotachophoresis with Poiseuille counterflow

A particular mode of isotachophoresis (ITP) employs a pressure-driven flow opposite to the sample electromigration direction in order to anchor a sample zone at a specific position along a channel or capillary. We investigate this situation using a two-dimensional finite-volume model based on the Nernst-Planck equation. The imposed Poiseuille flow profile leads to a significant dispersion of the sample zone. This effect is detrimental for the resolution in analytical applications of ITP. We investigate the impact of convective dispersion, characterized by the area-averaged width of a sample zone, for various values of the sample P\'{e}clet-number, as well as the relative mobilities of the sample and the adjacent electrolytes. A one-dimensional model for the area-averaged concentrations based on a Taylor-Aris-type effective axial diffusivity is shown to yield good agreement with the finite-volume calculations. This justifies the use of such simple models and opens the door for the rapid simulation of ITP protocols with Poiseuille counterflow

Methods and Compositions for Expressing Multiple Genes in Plants by Alternate Splicing of a Polycistronic Message

The present invention provides a method and composition for expression of multiple genes from a polycistronic message in transgenic plants using genetic elements derived from the peanut chlorotic streak caulimovirus promoter-leader sequence and antisense sequence of PC1SV ORF VII. Also provided are compositions and methods for intron-mediated enhanced and regulated expression of genes in transgenic plants