Abstract: Provided herein are multiplex assays for detecting antibodies indicative of presence and stage of syphilis infection in an individual. Individuals infected with syphilis produce antibodies directed to syphilis components and the lipid cellular debris associated with the infection. The present disclosure represents the first combination of these diverse antibody targets in a single assay.

Abstract: An apparatus using field emission techniques to limit voltage on RF transmission lines. A voltage limiter comprises a cathode and an anode housed in an airtight tube, whereby the cathode comprises a field emitter array having a plurality of field tips distributed about the surface of an insulating layer, and a microstrip transmission line overlying the insulating layer and having a predetermined width to form electrical contact with a selected group of the field tips. The microstrip transmission line enables propagation of electromagnetic microwave energy over a bandwidth of multiple octaves. The field emitters enable the generation of a flow of electrons at a predetermined breakdown threshold voltage, without the necessity for an external source to induce electron flow. Generation of the electron flow by the field tips creates a reflection wave on the transmission line that interferes with the incident electromagnetic energy to limit the voltage on the transmission line.

Abstract: A passive RF limiting circuit device providing protection for receiver front ends and the like by utilizing PIN diodes acting as switching devices which transform a low-loss T-network attenuator circuit into a high-loss .pi.-network attenuator circuit under high power conditions.

Abstract: A monolithic microwave integrated circuit is enclosed within an ionizable gas filled housing having a terminal protection device integral with the circuit's substrate. A photon generating region extends within the substrate and along a portion of the surface area of the substrate for facilitating the ionizing of the gas. First and second electrodes, in contact with the substrate surface area and disposed on opposite sides of the photon generating region, have a plurality of cantilevered protrusions extending over the surface of the substrate and equally spaced from one another forming spark-gaps therebetween. One electrode is connected to an input to the device while the other is connected to ground.