Abstract: The invention includes a conductor with a first side and a second side. The conductor may be sized to have a cross-section diameter substantially similar to a Fermi wavelength of electrons in the conductor, the cross-section diameter being taken substantially perpendicular to a primary direction in which current could flow through the conductor. The conductor size may be selected so that when a magnetic field less than a threshold value is applied to the conductor, the first side of the conductor has a first magnetic state and the second side of the conductor has a second magnetic state. However, when a magnetic field of sufficient strength is applied to the magnetic conductor the first side and the second side will be caused to have the same magnetic state.

Abstract: A method and apparatus for measuring changes in cell volume generally includes introducing cells into a chamber having a volume between 2 and 100 times the volume of the introduced cell. A first electrically conductive extracellular fluid is introduced into the chamber and a current is applied. The current flow is measured. The first fluid is exchanged with a second electrically conductive extracellular fluid and a current is applied. The current flow is measured. The first current flow result and the second current flow result are used in conjunction with known current flows to monitor changes in the volume corresponding to fluid flow between the cell and an extracellular fluid.