Jackie Ferrier

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 We describe a new method that uses straightforward physics to apply force to substrate-attached cells. In this method, collagen-coated magnetic ferric oxide beads attach to the dorsal surface of cells via receptors of the integrin family, and a magnetic field gradient is applied to produce a force. In this paper we present a complete characterization of(More)
A simple steady state iterative solution of Münch pressure-flow in unbranched sieve tubes containing only water and sucrose is derived. The iterative equations can be solved on a programmable desk calculator. Solutions are presented for steady state transport with specific mass transfer rates up to 1.5 x 10(-5) mole second(-1) centimeters(-2) (= 18.5 grams(More)
The steady state solutions of two mathematical models are used to evaluate Münch's pressure-flow hypothesis of phloem translocation. The models assume a continuous active loading and unloading of translocate but differ in the site of loading and unloading and the route of water to the sieve tube. The dimensions of the translocation system taken are the(More)
Electrical cell-substrate impedance sensing (ECIS) was used to measure the time-dependence and frequency-dependence of impedance for current flowing underneath and between cells. Osteosarcoma cells with a topology similar to a short cylinder (coin-like) surmounted by a dome were used in this study. Application of a small step increase in net vertical stress(More)
A model is developed for a mechanism for the regulation of the width of ligament spaces and of other tissue spaces bounded by calcified surfaces. The proposed mechanism involves the transmission, detection, and retransmission of ion concentration waves by cells located on the calcified surfaces. It is assumed that these cells can use the information(More)
We measure the change in cell-substrate separation in response to an upward force by combining two relatively new techniques, Electric Cell-substrate Impedance Sensing (ECIS) to measure average cell-substrate separation, and collagen-coated magnetic beads to apply force to the top (dorsal) surface of cells. The collagen-coated ferric oxide beads attach to(More)
A hypothesis concerning the molecular-dynamical basis of osmosis is presented. According to this hypothesis, osmosis results from the attractive force between solute and water molecules, and the exclusion of the solute from the water transport channels of the membrane. Based on this hypothesis, the osmotic process is predicted to involve a large number of(More)
An important aspect of the interaction of a biological system with an externally produced electric field is that of charge separation and interfacial charging. This aspect has been ignored in some recent experimental and theoretical work. In the case of small regions of lower electrical resistivity imbedded in a higher resistivity medium, charge separation(More)
The time evolution of a Munch pressure-flow translocation system is calculated using a numerical computer method. Results are obtained for the time course of the system variables following application of a large resistance in the translocation path, intended to simulate a cold block. The resistance factor required to produce translocation inhibition(More)