Attaching certain ligands to antisense probes will hyperstabilize sense-antisense duplexes. The face portion comprises a rubber layer over a burlap layer clamped onto the edge of a circular metal plate. The ore to be concentrated is fed to a bin in batch form and carried from the bin by a screw through a screen to the table. A regulating cone is attached to the open end of the inspection glass, whereby the free end of the indicator plunger is guided through the regulating cone and bears a flow body immersed in the conical bore. The iontophoresis electrode assembly may also be used to reduce or temporarily eliminate neuropathic pain.