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: 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: 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: 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: 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: 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: A method of analyzing selected regions of semiconductor systems to determine the uniformity of distribution of trapped charges or electric dipoles at the surface of the semiconductor or in a dielectric or insulating material associated therewith, the method including the steps of applying an adjustable bias potential to the semiconductor system to produce an electric field within the system; directing a beam of electromagnetic radiation onto a selected region of the semiconductor system in which the electric field exists to induce a photocurrent output from the system, the beam including photons of energy greater than the band gap energy of the semiconductor; adjusting the bias potential to vary the direction and/or the magnitude of the electric field; measuring the photocurrent output induced by the beam as a function of the bias potential; and determining the uniformity of distribution of trapped charges or electric dipoles in the selected region of the semiconductor system from the measured photocurrent ou