Abstract: Whole blood is mixed with a reticulocyte reagent system that has a reticulocyte staining reagent and a diluent reagent, used in combination. This mixture is incubated at room temperature for between about 15 minutes to about 4 hours. The incubated mixture is then analyzed and the light scattering properties of the cells are detected, collected, differentiated and quantitized. Data gathering includes, at least, 10 and 90 degree light scatter detection.

Abstract: An improved fluorescence detection system is provided which utilizes a relatively high powered, relatively high repetition rate light source with high speed detection electronics to increase system sensitivity and accuracy. In the preferred embodiments, a laser diode is the light source. In one embodiment, the position of a time window is varied to compile a decay profile of a fluorophore. In another embodiment, the time to detection of a photon is used to compile the decay profile. In one aspect of this invention, a histogram of the fluorescence decay is generated by determining a preliminary histogram of the shape and multiplying it by the ratio of the total number of events divided by the number of events comprising the preliminary histogram. In another aspect of this invention, the time of detection after excitation of the photon is started from a random time, such as after a preceding event is detected and the data stored.

Abstract: Computer-controlled method and apparatus for automatic melt index testing, including a housing with a base carrying a heater block having a bore therein for receiving a metal cartridge. A cartridge carousel is rotatably carried on the base, and carries a plurality of such cartridges, each cartridge having a plug at the bottom end thereof with a orifice through the plug, and each cartridge having a bore therein for receiving a sample of a test substance and for receiving a piston on top of the pellets. A lift arm grasps the cartridges, one at a time, and places each cartridge into the heater block, under the control of a microcomputer, by both lifting and rotating the transfer arm. The transfer arm includes a solenoid-operated grip for grasping the cartridges.The test unit carries a lift mechanism with a weight mounted atop a tamping rod, and an optical sensor for determining the height of the weight relative to the lift machinism.

Abstract: In a system for analyzing the elemental or molecular composition of a sample wherein the sample components are excited through collision with an active metastable gaseous species, the excited sample components emitting a characteristic wavelength of light which may be detected, the system including a microwave cavity through which the gaseous species flows and a microwave source coupled to the cavity, the microwave discharge exciting the gaseous species, there is disclosed an improved liquid sample introduction system which causes complete vaporization and disassociation of the sample. The sample is preferably aspirated directly into the microwave discharge within which the active gas is generated. A novel sample and gas injection probe is also disclosed.

Abstract: A system for the detection of precipitate-forming antigens by means of the reaction with their corresponding antibodies is disclosed. The reaction of precipitate-forming antigens with their respective antibodies produces a precipitate in proportion to either the antibody concentration or the antigen concentration, depending on which is present in excess. The method does not require formation of actual precipitate, but measures the formation of "scattering centers" -- i.e., molecular aggregates of sufficient size to produce measurable scatter of light. The quantity of scattering centers formed is measured by nephelometric means and the measuring system performs an immunonephelometric analysis. In particular, the rate of change of the nephelometric signal with respect to time is measured and the peak rate and time to the peak rate established. From these simultaneous measurements both the antigen/antibody concentration and the condition of antibody or antigen excess are determined.