Abstract: A 4-methylumbelliferyl phosphate substrate for use in conducting an immunoassay is disclosed. The substrate contains 0.1 gram mole per liter 2-amino-2-methyl-1-propanol, 0.01 to 0.05 gram mole per liter EDTA, added as trisodium EDTA, 1 gram per liter sodium azide, 1.2 milligram mole per liter 4-methylumbelliferyl phosphate and 4 milligram moles per liter tetramisole. The pH of the substrate disclosed is 10.3.

Abstract: Apparatus for measuring electrolyte concentrations in fluid samples. The apparatus includes an ion selective electrode capable of generating a voltage differential having a magnitude related to the concentration of the corresponding electrolyte in the sample. A voltage to optical transducer circuit is provided to convert the voltage differentials to a digital code and then to an optical signal which is related to the concentration of the electrolytes. The optical signals are suitable for detection by conventional optical detector apparatus of assay instruments. A passive duplex transfer is utilized to simultaneously read one optical signal while transferring the next bit of the digital code. The duplex transfer configuration also makes novel use of the photodetection properties of an LED.

Abstract: A control system for the working piston of a valveless metering pump for the precision delivery of fluids to a plurality of sequentially spaced output ports is adapted to control and alter the speed of rotation of the pump piston depending on predetermined angles of rotation of the piston as it cycles.

Abstract: A method for separating HDL from whole blood anticoagulated with EDTA is disclosed. The method includes, as a first step, mixing the anticoagulated whole blood with an aqueous solution composed of magnesium .sup.++ cations and dextran sulfate 500 in such proportions and of such concentration(a) that substantially all of the LDL and VLDL lipoproteins and substantially all of the chylomicrons are precipitated while(b) substantially all of the HDL remains in solution.The method also includes the step of sedimenting the precipitated lipoproteins, the chylomicrons and the red blood cells by centrifuging, which can be low gravity centrifuging, and can include the step of determining the cholesterol, triglyceride, phospholipid or protein content of the supernatant.

Abstract: The current invention is a method, kit and reagents for detecting cobalamins in a sample. The method involves introducing into the sample a first conjugate of a latex or latex-like solid phase linked to affinity purified intrinsic factor with a first linking group at least three angstroms long. The first conjugate and the bound cobalamins in the sample are then exposed to a second conjugate of a cobalamin linked to a detectable enzyme to produce second conjugate bound to first conjugate and unbound second conjugate. The enzyme activity associated either with the solid phase first conjugate or the unbound second conjugate is then detected. By linking affinity purified intrinsic factor to a latex or latex-like solid phase with a first linking group at least three angstroms long, an exzyme assay can be performed which detects levels of cobalamins in patient samples within or below normal ranges found in such samples.

Abstract: A fluid flow system for use with an analytical instrument is provided having a sample reservoir for holding a liquid suspension of particles to be analyzed, a reagent reservoir for holding a reagent, pump means for pumping fluid to and from the reservoirs to a pumping reservoir, valve means for restricting fluid flow from the reagent reservoir to the pumping reservoir, first conduit means interconnecting the reagent and sample reservoirs, second conduit means connecting the sample and pumping reservoir at a point just behind a metered aperture provided in an end of the second conduit means, and in a preferred embodiment, third conduit means connecting the first and second reservoirs and valve means for restricting fluid flow from the reagent reservoir to the pumping reservoir through the third conduit means, the end of each of the conduit means being maintained at the same physical level.

Abstract: A digital circuit both provides multiphasic timing signals and regulates the operating voltage of a non-ideal power source. In one embodiment, a delay line is provided whose delay characteristics vary inversely with operating voltage. Control gates are connected to selected outputs of the delay line to receive at differing times a control signal propagated through the delay line. In a preferred embodiment the control gates generate output signals the duration of which are determined by the delay characteristics of the delay line (and thus by the level of the operating voltage), such that the output signal duration increases in response to increases in operating voltage. The output signals activate current sinks or loads which increase the current drain on the non-ideal power source, thereby depressing its voltage.

Abstract: A plurality of disposable cartridges, each having a plurality of wells including at least one assay reaction well, are loaded in a plurality of openings arranged radially around a rack of a carousel. Securing of the cartridges in a predetermined orientation and position in said openings is ensured by means of alignment and securing means on the cartridges and corresponding means on the rack. A locking hub with tangs is mounted on the rack and is rotated to cause the tangs to contact locator tabs on each cartridge to force locator nubs on each of the cartridges radially into corresponding notches on the rack, and to accurately wedge the cartridges against the outer periphery of the rack. The carousel indexes for positioning the cartridges under a variety of stations, one of which generally contains an optical reader such as a fluorometer.

Abstract: Novel methods for covalent attachment of antibodies, antigens, or other molecules to solid phases using extended length heterobifunctional crosslinking reagents are disclosed. The resulting derivatized solid phases can be used in diagnostic assays.

Abstract: Apparatus for measuring electrolyute concentrations in fluid samples. The apparatus includes an ion selective electrode having a plurality of ion selective detection sites. Each site has an affinity for a preselected electrolyte of interest and generates a potential having a magnitude related to the concentration of the corresponding electrolyte in the sample. A voltage to optical transducer circuit is provided to convert the voltage differentials to optical signals having intensity related to the concentration of the electrolytes in a first embodiment, a digital code related to the concentration of the electrolytes in a second embodiment, and an optical absorption or density value related to the concentration of the electrolytes in a third embodiment. The optical signals are suitable for detection by conventional optical detector apparatus of assay instruments and may be processed using conventional two point linear interpolation techniques to determine the concentrations of the preselected electrolytes.

Abstract: An optical code reader system includes an optical code reader and a corresponding optical code format. The code reader includes a detector circuit for establishing an adaptive threshold level related to the difference in successive positive and negative peaks of the analog signal corresponding to white and black areas of the code. The code format comprises a plurality of alternating encoded black and white areas bounded by white quiet zones and black preset areas associated with the quiet zones for presetting the threshold value of the detector circuit to a known level before the code is read.

Abstract: A preferred embodiment of a self-balancing reflectometer is disclosed in conjunction with a system including an RF source, an RF load, and an RF transmission channel that carries RF signals transmitted by the source to the load. The self-balancing reflectometer includes a load current sampler that generates a first sample signal related to load current by a first fixed value of gain and a load voltage sampler that generates a second sample signal related to load voltage by a voltage-responsive second variable value of gain. The first sample signal is subtracted from the second sample signal and the resulting difference signal is applied to the RF port of a double balanced mixer. The RF voltage signal appearing at the load is applied to the LO port of the mixer, which generates an IF signal that varies with both rapid load impedance modulation corresponding to load data and long term basal variations in load impedance unrelated to load data.

Abstract: A plurality of disposable cartridges, each having a plurality of wells including at least one assay reaction well, are loaded in a plurality of openings arranged radially around a rack of a carousel. Securing of the cartridges in a predetermined orientation and position in said openings is ensured by means of alignment and securing means on the cartridges and corresponding means on the rack. A locking hub with tangs is mounted on the rack and is rotated to cause the tangs to contact locator tabs on each cartridge to force locator nubs on each of the cartridges radially into corresponding notches on the rack, and to accurately wedge the cartridges against the outer periphery of the rack. The carousel indexes for positioning the cartridges under a variety of stations, one of which generally contains an optical reader such as a fluorometer.

Abstract: A two-part test cartridge for use in a centrifugal analyzer for measuring the concentration of different electrolytes in blood or blood serum samples has one part which is disposable and which is characterized by a sample entry port, one or more filled calibrant chambers, a waste chamber and passages between various chambers; and a second, mating part which is reusable and which is characterized by an ISE, a power supply and circuitry therefor, and a series of chambers and passages adapted for communication with the series of chambers and passages in the disposable part.

Abstract: An apparatus for the application of coating material onto elongated food products wherein the applicator nozzle and nozzle opening portion of the apparatus correspond to the side surfaces of the elongated food product. The food product to be coated is passed before nozzles discharging impelled coating material from a coating material supply source that meters desired amounts of coating material to the blower device.

Abstract: The invention describes a wettable and soluble acidulent comprising fumaric acid and natural juice solids. The fumaric acid is employed in amounts of at least 50% by weight of the acidulent and the natural juice solids are employed in amounts of at least 5% by weight. The acidulent may additionally contain a sweetener employed in amount of at least 2% by weight.

Abstract: An .alpha., .beta.-keto-imine having a nutty corn, cereal aroma which may be used as a flavoring composition for food and having the structure: ##STR1## and R.sup.1, R.sup.2 and R.sup.3 are selected from the group consisting of a saturated or unsaturated alkyl straight or branched chain hydrocarbon having from C.sub.1 to C.sub.3 carbon atoms but preferably having from C.sub.1 to C.sub.2 carbon atoms. Alternatively R.sup.3 may also be (CH.sub.3).sub.n -SH wherein n is 1 or 2.

Abstract: Extruded shrimp analogs are prepared from a vegetable protein and high amylose starch based composition which is in oriented fibrous form and wherein the amylose fraction is complexed with a lipid.