A method and frequency converter for a radio rapid frequency signal scanning and including a local oscillator signal synthesis source producing a local oscillator signal with local oscillator bursts. The reflector has reflective sides and a light exit. A product or service related to the completion of the transaction is selected, a vendor ordering profile is selected, a vendor is selected according to a distribution selection method or by selection of a user, and the selected product or service is ordered from the selected product vendor. A time average value of a digital output of the clocked counter is then related to the resistance of the memory cell, and hence to the resistive state of the resistive memory element. The invention provides methods for the oxidative refolding of a hepcidin polypeptide to a form that is mature, bioactive and folded as in the native configuration and molecular mass; a method for measuring the level of native, bioactive hepcidin in a vertebrate animal. Redundant relationships or connections between nodes are systematically hidden but in such a way that the removed relationships or connections can be inferred from the remaining relationships in the diagram.