Abstract: A metering and transfer valve assembly particularly for use in particle analyzing apparatus for the study of particles in liquid suspension, the valve assembly having at least pair of inner and outer valve elements coaxially arranged in face to face frictional sealing engagement with a center valve element, each of the valve elements being independently rotatable, first passages defining a first flow path through the assembly, second passages defining a second flow path through the assembly, the first passages including a metering chamber for measuring and transferring a precise sample aliquot of sample flowing in the first flow path into the second flow path, the first flow path leading to a first exterior location and the second flow path leading to a second exterior location, and a drive fluid being introduced to the second flow path subsequent to transfer of said aliquot thereto for propelling said aliquot along the second flow path to the second exterior destination, the second destination being a flow s

Abstract: A method and apparatus for accelerating at least one definitive biological reaction including increasing the accuracy of determinations made therefrom. The reaction involves selected viable biological cells which are prepared in a small sample volume and rapidly mixed with microspheres having antibody specific at least to specific ones of the cells bound thereto. The microspheres can be magnetic and the bound cells can be magnetically removed to analyze the remaining blood cell populations. The microspheres can be introduced sequentially or simultaneously.

Abstract: A metering and transfer valve assembly particularly for use in particle analyzing apparatus for the study of particles in liquid suspension, the valve assembly having at least pair of inner and outer valve elements coaxially arranged in face to face frictional sealing engagement with a center valve element, each of the valve elements being independently rotatable, first passages defining a first flow path through the assembly, second passages defining a second flow path through the assembly, the first passages including a metering chamber for measuring and transferring a precise sample aliquot of sample flowing in the first flow path into the second flow path, the first flow path leading to a first exterior location and the second flow path leading to a second exterior location, and a drive fluid being introduced to the second flow path subsequent to transfer of said aliquot thereto for propelling said aliquot along the second flow path to the second esterior destination, the second destination being a flow s

Abstract: A method and apparatus for accelerating at least one definitive biological reaction including increasing the accuracy of determinations made therefrom. The reaction involves selected viable biological cells which are prepared in a small sample volume and rapidly mixed with microspheres having antibody specific at least to specific ones of the cells bound thereto. The microspheres can be magnetic and the bound cells can be magnetically removed to analyze the remaining blood cell populations. The microspheres can be introduced sequentially or simultaneously.

Abstract: Automatic biological sample mixing apparatus for use in flow cytometry, wherein a sample container is secured loosely at its top by means of a multi-reagent dispensing head; and the container is mounted at its bottom on a resilient support disposed on an elliptically rotated member, to cause reagents introduced into the container to be thoroughly mixed with a sample in the container in a fast, efficient, gentle, and accurately repeatable manner.

Abstract: Disclosed is a flow-through, particle analyzer and sorter apparatus for simultaneous optical and electrical impedance measurements on a stream of particles, comprising a flow cell having a pair of channels fluidly connected by a particle sensing aperture, through which the particles pass and are analyzed; a nozzle mounted at the end of the downstream channel so as to define a flow chamber; a sheath liquid which is introduced at the bottom of the flow chamber to hydrodynamically focus the particle stream and to jet the same in a liquid jet from the nozzle; and a system for creating droplets from the liquid jet and for thereafter sorting the droplets.

Abstract: A variable and reversible transmission, in which two co-linear shafts are provided with adjustably-locatable generally semi-spherical drive components or heads, with control means for changing and holding selected adjustments of the heads; and the heads drivingly engage one another, in whatever settings they are positioned, by acting through a pulley belt which may be either an idler for only transmitting torque from one head directly to the other, or may be a power member transferring power to another set of such heads, achieving both variability and reversibility of drive.

Abstract: A particle analyzer for a sample suspension of particles originating in a container in which: a flow director is mounted between the container and a first chamber, a particle sensing aperture is mounted between the first chamber and a second chamber, a liquid sheath is introduced into the first chamber for hydrodynamically focusing the particles through the sensing aperture, an electrical current passes through the sensing aperture for generating impedance signals, the pressure drop is regulated across the flow director to assure a constant flow of the suspension through the flow director and the aperture, and the flow director is formed into an optical element for viewing the sensing aperture.