Abstract: A constant pathlength multi-assay plate cover for multi-assay plates, comprising, a flat top side and a flat bottom side, the bottom side having solid cylindrical projections of equal length extending downwardly from the flat bottom side, wherein each cylindrical projection is centered about the optical axis passing through a corresponding sample well of a multi-assay plate, thereby eliminating the meniscus and evaporation effects.

Abstract: Disclosed are photometric methods and devices for determining optical pathlength of liquid samples containing analytes dissolved or suspended in a solvent. The methods and devices rely on determining a relationship between the light absorption properties of the solvent and the optical pathlength of liquid samples containing the solvent. This relationship is used to establish the optical pathlength for samples containing an unknown concentration of analyte but having similar solvent composition. Further disclosed are methods and devices for determining the concentration of analyte in such samples where both the optical pathlength and the concentration of analyte are unknown. The methods and devices rely on separately determining, at different wavelengths of light, light absorption by the solvent and light absorption by the analyte. Light absorption by the analyte, together with the optical pathlength so determined, is used to calculate the concentration of the analyte.

Abstract: The present invention encompasses a capture membrane comprising a porous filter membrane having a hapten bound directly or indirectly to the membrane wherein complexes formed by specific binding having an anti-hapten bound to a binding member of the specifically binding complex are removed from a solution by the hapten as the solution passes through the membrane. In the preferred embodiment biotin is the hapten and avidin or streptavidin is the anti-hapten.

Abstract: The present invention method may be practiced with many different types of biological cells. Biological cells may be either eucaryotic or procaryotic cells. The cells may be in the form of tissue slices or tissue homogenates or may be in the form of suspensions of intact single cells. The intact single cells may be grown in cell culture, as described in the previous examples, or may be obtained from blood, other body fluids, or from tissue biopsy. The cells may be cells containing receptors transfected by recombinant DNA techniques, or alternatively may be cells naturally responding to cell-affecting agents. The cells may be fresh or may have been previously preserved by dehydration, refrigeration, or freezing. When the cells have been preserved, preservative agents (for example dimethylsulfoxide in the case of frozen cells) may be removed prior to measurement of the effect of cell-affecting agents on rates of extracellular acidification. The cells may be either plant cells or animal cells.

Abstract: Compounds and methods for detecting the incorporation of a hapten into a protein or macromolecule are disclosed. The compounds comprise haptens bound directly or indirectly to a chromophoric group and a macromolecule-reactive group, whereby incorporation of the hapten into a protein or other macromolecule may be detected.

Abstract: The present invention relates to a system for detecting, in a reliable, precise and highly sensitive manner, biochemical agents such as enzymes that catalyze a redox potential change. One electrode is used to measure redox potential changes in an aqueous electrolyte containing the biochemical agents. Another electrode is used to deliver a feedback current to the electrolyte in response to measured Changes in electrolyte redox potential. The amount of feedback current or charge delivered through the electrode to the electrolyte is sufficient in magnitude to maintain a constant redox potential. Quantitation of the amount of feedback current or charge necessary to maintain the constant redox potential may then be used to determine the amount of biochemical agents present. Alternatively, the redox potential need not be kept constant, but instead may be allowed to reach a new steady-state.

Abstract: The present invention relates to a photometric device for measuring optical parameters. The invention functions in the ultraviolet light range through use of a monochromator and splits the test light in multiple channels by a rotor assembly, including a mirror.

Abstract: This invention encompasses porous microchambers which contain cells and permit liquid to flow in and out of the chamber while retaining cells within the chamber. These porous microchambers serve as disposable devices for placing cells in a microflowchamber so that properties of the cells within the porous microchamber can be measured.

Abstract: This invention encompasses a work station for conducting assays which comprises filtering assembly, a slide reading assembly, and a slide with a porous filter membrane wherein the slide has a means for aligning the slide within the filter assembly to filter reagents on predetermined portions of the porous filter membrane and also to position the slide in the slide reading assembly so that detection will occur in those same predetermined locations.

Abstract: Enzyme or substrate determinations can be achieved by employing an organic second substrate, which produces a product which may be coupled with a metal inorganic redox couple capable of interacting with and affecting the potential of a metal electrode on a semiconductor surface. Particularly, hydrogen peroxide or indoxyl phosphate are coupled with iron- or ruthenium-containing ionic redox couples for determination with a noble metal electrode.

Abstract: Photoresponsive devices including a photoresponsive electrode are provided, and methods for their use to measure changes in environment at a site at or about the surface of the photoresponsive device. By employing a source of light for irradiating a site on the surface and means for biasing the photoresponsive electrode in relation to a counterelectrode, a variation in electrical signal can be related to a change in a medium in photoresponsive modulation relationship to the photoresponsive electrode surface.

Abstract: Methods and apparatus are disclosed for detecting the effects of cell affecting agents on living cells. The method steps include providing living cells that are retained in a micro flow chamber. The micro flow chamber is adapted for either continuous or intermittent flow of solutions or suspensions in intimate contact with the cells. The solutions or suspensions, which contain a cell affecting agent, are then flowed in intimate contact with the cells and the pit is measured.

Abstract: An ultraviolet radiation transparent multi-assay plate for ultraviolet absorption spectroscopy of ultraviolet absorbing liquids comprising a plurality of cylinders fixed in a frame each covered at the bottom with a portion of an ultraviolet transparent sheet material sealed to the bottom wall of the cylinder to form a non-leaking multi-assay plate well.

Abstract: Methods and apparatuses are described for determining the presence of an analyte in a sample suspected of containing the analyte. The method comprises contacting a concentrate of a determinable element capable of being detected by means of a semiconductive electrode with the electrode in the presence of a relatively large volume of an assay medium. The determinable element is present in the concentrate in the amount related to the amount of analyte present in the sample. The volume of the medium in diffusive communication with the concentrate is then reduced and the determinable element is detected by means of the effect that the determinable element has on the semiconductive electrode.

Abstract: Methods are disclosed for detecting the effects of cell affecting agents on living cells. The method steps include providing living cells that are retained in a micro flow chamber. The micro flow chamber is adapted for either continuous or intermittent flow of solutions or suspensions in intimate contact with the cells. The solutions or suspensions, which contain a cell affecting agent, are then flowed in intimate contact with the cells and at least one effect of the cell affecting agent on the cells is measured by an appropriate detecting means, which is operatively associated with the micro flow chamber.

Abstract: Compounds and methods for detecting the incorporation of a hapten into a protein or macromolecules are disclosed. The compounds comprise haptens bound directly or indirectly to a chromophoric group and a macromolecules-reactive group, whereby incorporation of the hapten into a protein or other macromolecules may be detected. The disclosure includes a compound of the formula: ##STR1## wherein n.sub.1 is 1, 2, 3, 4, 5, 6 or 7;n.sub.2 is 0, 1, 2, 3, 4, 5, 6 or 7;R.sub.1 is either a carboxytetramethyl-rhodamyl, sulforhodamyl101, or dinitrophenylaminohexanoyl group; andR.sub.2 is --CO.sub.2 H, --NH.sub.

Abstract: Apparatus and methods are provided for multiple detection of analytes employing semiconductor capacitance as the signal modulated by the analyte. A plurality of semiconductor capacitors are organized for detection (at individual sites) of changes in capacitance which are related to changes in a fluid medium, where the change can be related to the presence of an analyte. Circuitry is designed to substantially maximize sensitivity.

Abstract: An analyzer with an improved rotor structure for analyzing solid-containing and solid free liquids having an improved rotor design that utilizes chambers and channels that operate by centrifugal force and capillary action to separate and meter the liquids for testing purposes.

Abstract: A multibeam photometric measuring device includes a light assembly comprising a single modulated light source along with a filter assembly for passing only a desired band of wavelengths and an optical system for suitably focusing light from the light source. A plurality of light transmitting means accept light and transmit it individually to each of the plurality of sites disposed on a multi-well sample plate.Enhancement of color distribution resulting from chromogenic reactions is provided by automatic agitation of the reacting agents within the sample wells before a reading is taken at each of the sampling intervals of a kinetic measurement sequence.

Abstract: This invention encompasses porous microchambers which contain cells and permit liquid to flow in and out of the chamber while retaining cells within the chamber. These porous microchambers serve as disposable devices for placing cells in a microflowchamber so that properties of the cells within the porous microchamber can be measured.