Abstract: A system for conveying sheets of thin substrate having low sheet stiffness while controlling and limiting the angle of wrap of the substrate on the roller, and a sheet cleaning apparatus employing the wrap-limiting system. A substrate conveyance roller is provided with a plurality of circumferential grooves spaced along the roller. Into each groove is disposed a substrate guide in near-tangential relationship with the surface of the roller at the point on the roller where stripping of the substrate from the roller surface is desired. In a preferred embodiment of a wrap-limiting system in accordance with the invention, one or more substrate guides are provided which extend through the grooves both upstream and downstream of the roller along the substrate conveyance path. The points at which the guide enters and leaves the groove define and limit the wrap angle assumable by the substrate on the roller.

Abstract: A planar log periodic quad array comprising a two-conductor twisted transmission line to which log periodic elements are connected. The elements are arranged in two sets on opposite sides of the transmission line and are in a common plane. Each element has two points of connection with a particular conductor of the transmission line and comprises two sides each extending from a respective one of the two points of connection to the particular conductor to join at a corner which lies on an imaginary line perpendicular to the transmission line at its center feed point. Immediately adjacent elements of one set are connected to alternate ones of the two conductors of the transmission line and each element of the other set has a general geometric symmetry about the transmission line with respect to a corresponding element of the one set but with its points of connection to the transmission line being to the opposite conductor. The array is suited for active or passive use and has a broadband characteristic.

Abstract: A kit and method for the radioimmunoassay (RIA) for erythropoietin. Also, a method for purifying erythropoietin and purified labelled erythropoietin-conjugate for use as a tracer in the RIA.