Abstract: A system for assaying a fluid sample, typically employing a fluorescent tag, the system comprising a lens capable of focussing both excitation and fluorescent radiation, a fluid-flow conducting conduit being provided in the lens extending transversely of the optical axis of and through the focal region of the latter. One or more mechanical screens are disposed adjacent to the focal region in the conduit to arrest passage of beads as a function of bead diameter. The beads, precoated with at least a moiety of a ligand/conjugate complex, e.g. a specific-binding ligand, are preferably substantially transparent to both the excitation and fluorescent radiation.

Abstract: A system for assaying a fluid sample by detection of radiation emitted from a ligand/conjugate complex formed on a plurality of beads dimensioned within a specified range of diameters, the beads being disposed as a porous mass in a conduit adjacent a fluid-porous screen having pores of lesser diameter than the range of diameters of the beads. A plurality of paramagnetic particles is suspended across the conduit by a magnetic field of sufficient intensity to array the paramagnetic particles as the fluid-porous screen.

Abstract: A system for assaying a fluid sample, typically employing a fluorescent tag, the system comprising a lens capable of focussing both excitation and fluorescent radiation, a fluid-flow conducting conduit being provided in the lens extending transversely of the optical axis of and through the focal region of the latter. One or more mechanical screens are disposed adjacent to the focal region in the conduit to arrest passage of beads as a function of bead diameter. The beads, precoated with at least a moiety of a ligand/conjugate complex, e.g. a specific-binding ligand, are preferably substantially transparent to both the excitation and fluorescent radiation.

Abstract: A system for assaying a fluid sample, typically employing a fluorescent tag, the system comprising a lens capable of focussing both excitation and fluorescent radiation, a fluid-flow conducting conduit being provided in the lens extending transversely of the optical axis of and through the focal region of the latter. One or more mechanical screens are disposed adjacent the focal region in the conduit to arrest passage of beads as a function of bead diameter. The beads, precoated with at least a moiety of a ligand/conjugate complex, e.g. a specific-binding ligand, are preferably substantially transparent to both the excitation and fluorescent radiation.

Abstract: A hand press which includes a first lever arm having adjacent one end thereof a hollow receptacle having one end opened, the other end covered by a perforated screen, and a second lever arm pivotally mounted at the one end of the first lever arm. A piston is fixededly positioned on the second arm for insertion into the open end of the receptacle, the receptacle typically being shaped as a toroidal segment having its axis of elongation conforming to an arc having a mean radius of curvature defined by the distance between the pivot point and the center of the face of the piston. The periphery of the piston face is provided with a ring to insure a tight sliding fit of the piston in the receptacle.