Abstract: A method and apparatus for a slide loading/unloading system is described. A slide storage cassette is provided to store slides in which the slides are stored with an end protruding from the slide storage cassette. A slide feeder is described having grippers, which grip the end of a slide and transport the slide to a sample holder. The sample holder receives and retains the transported slide.

Abstract: A fibre optic coupling plate (24) has a sample viewing face for receiving light from a sample (12), an output window (18) for conveying sample originating (emitted) light to an imaging detector and an additional window through which excitation radiation can be projected. A primary light is provided through the plate made up of optical fibres which will convey light entering the viewing face, directly and with minimal loss, to the output window, and a secondary light path separate from the primary light path, by which excitation radiation entering the additional window is conveyed to the viewing face for irradiating the sample.

Abstract: A microarray storage device includes a cassette having top, bottom and opposite side walls, the front and rear of the cassette being open. The side walls are formed with a multiplicity of parallel rails spaced along the heights of the walls which define compartments in the cassette for supporting a multiplicity of microarrays one above the other. The depth of the cassette is such that the microarrays supported in the compartments project appreciably from the front and/or rear of the cassette. Integral springs are formed in the side walls of the cassette which press down directly on the side edge margins of the microarrays so as to releasably retain the microarrays in their respective compartments.

Abstract: A low volume liquid handling system is described which includes a microdispenser employing a piezoelectric transducer attached to a glass capillary, a positive displacement pump for priming and aspirating liquid into the microdispenser, controlling the pressure of the liquid system, and washing the microdispenser between liquid transfers, and a pressure sensor to measure the liquid system pressure and produce a corresponding electrical signal. The pressure signal is used to verify and quantify the microvolume dispensed and is used to perform automated calibration and diagnostics on the microdispenser.

Abstract: In a microvolume liquid handling system, a system reservoir is connected with tubing to a pressure control system for controlling the liquid system pressure in the system reservoir. The system reservoir is coupled to one or more microdispensers through a distribution tube having a branched section for each microdispenser. In this embodiment, each microdispenser is coupled to its own flow sensor and to enable a system controller to respectively measure and control the flow of liquid in the each microdispenser.

Abstract: The presence of renilla luciferase alone or both renilla luciferase and firefly luciferase is detected by adding reagent mixture(s) to a biological sample and producing glow luminescence having a duration of at least an hour. In producing luminescence from renilla luciferase alone, a reagent is added comprising coelenterazine, and dithiothreitol (DTT) and EDTA, or functional equivalents of DTT and EDTA. Luminescence from samples containing both firefly luciferase and renilla luciferase is produced by first adding a reagent comprising firefly luciferin, ATP, co-factors necessary for firefly luciferase activity (e.g., Ca+2 and Mg+2), dithiothreitol (DTT) or functional equivalents thereof, and AMP. Following measurement of the firefly luciferase, coelenterazine and EDTA, or functional equivalents of EDTA, are added, and the luminescence produced by renilla luciferase is measured.

Abstract: A low volume liquid handling system is described which includes a microdispenser employing a piezoelectric transducer attached to a glass capillary, a positive displacement pump for priming and aspirating liquid into the microdispenser, controlling the pressure of the liquid system, and washing the microdispenser between liquid transfers, and a pressure sensor to measure the liquid system pressure and produce a corresponding electrical signal. The pressure signal is used to verify and quantify the microvolume dispensed and is used to perform automated calibration and diagnostics on the microdispenser.

Abstract: A low volume liquid handling system is described which includes a microdispenser employing a piezoelectric transducer attached to a glass capillary, a positive displacement pump for priming and aspirating liquid into the microdispenser, controlling the pressure of the liquid system, and washing the microdispenser between liquid transfers, and a pressure sensor to measure the liquid system pressure and produce a corresponding electrical signal. The pressure signal is used to verify and quantify the microvolume dispensed and is used to perform automated calibration and diagnostics on the microdispenser.

Abstract: A low volume liquid handling system is described which includes a microdispenser employing a piezoelectric transducer attached to a glass capillary, a positive displacement pump for priming and aspirating liquid into the microdispenser, controlling the pressure of the liquid system, and washing the microdispenser between liquid transfers, and a pressure sensor to measure the liquid system pressure and produce a corresponding electrical signal. The pressure signal is used to verify and quantify the microvolume dispensed and is used to perform automated calibration and diagnostics on the microdispenser.

Abstract: A low volume liquid handling system is described which includes a microdispenser employing a piezoelectric transducer attached to a glass capillary, a positive displacement pump for priming and aspirating liquid into the microdispenser, controlling the pressure of the liquid system, and washing the microdispenser between liquid transfers, and a pressure sensor to measure the liquid system pressure and produce a corresponding electrical signal. The pressure signal is used to verify and quantify the microvolume dispensed and is used to perform automated calibration and diagnostics on the microdispenser.

Abstract: A scintillation measurement system for measuring optical events produced by scintillators in response to the radioactive decay of a constituent or constituents of a sample to be measured comprises a sample support for positioning a sample in a sample well; a bismuth germanate (BGO) scintillation crystal, such as Bi.sub.4 Ge.sub.3 O.sub.12, located adjacent the sample well; a plurality of photodetectors located outside the bismuth germanate crystal for detecting optical events occurring in the sample well or in the bismuth germanate crystal and converting those optical events into electrical pulses; and a pulse analyzing system for receiving the electrical pulses from the photodetectors and determining whether such pulses represent .alpha., .beta. or .gamma. events. This system can be used with samples containing .alpha., .beta. and .gamma. emitters, or any combination thereof.

Abstract: A microplate forms a multiplicity of sample wells for holding samples to be assayed by light emissions or light transmission. The microplate comprises a unitary upper plate and a unitary lower plate. The unitary upper plate forms the side walls of the sample wells, while the unitary lower plate forms the bottom walls of the sample wells. The side walls are opaque so that light cannot be transmitted between adjacent wells through the side walls. The bottom walls are transparent to allow the transmission of light therethrough. Bands of opaque material surround the bottom wall of each well and are located below a level of an upper surface of, the bottom wall of each well. The bands of opaque material are constructed and arranged to block the transmission of light between adjacent wells through the lower plate.

Abstract: An arrangement senses a liquid level by monitoring the peak capacitance formed between a probe and the liquid as the probe approaches or departs from the liquid. In an automated system, a computer controls the position of a pipette probe for aspirating or dispensing liquid in the vessel. The charge developed via the capacitance on the probe is coupled to a capacitive sensor circuit which provides a peak detector with an amplified signal representing the peak capacitance between the probe and the liquid. This amplified signal is detected by a peak-capacitance discrimination circuit, the output of which is monitored by the computer for determining the precise position of the probe with respect to the liquid surface level. Other aspects of the present invention include a negative-static elimination circuit coupled to the output of a detector latch and a positive-static elimination circuit coupled to the input of the detector latch.

Abstract: A normalization system for multi-photodetector single photon counting luminescent measuring systems and a standard for use in the same. The method comprises calculating one or more counting ratios for each photodetector in the single photon counting system and multiplying counts of unknown samples by the inverse of the appropriate counting ratio. A counting ratio for a particular photodetector is calculated by dividing the count of a standard measured by the photodetector by the count of the same standard measured by a reference photodetector. The particular standard developed employs calcium tungstate:lead as a scintillator and tritium or carbon-14 thymidine as a means of exciting the scintillator. This standard has the advantages of providing a good model of typical luminescence chemistry and producing an emission pattern which is susceptible to single photon counting.

Abstract: A microplate forms a multiplicity of sample wells for holding samples to be assayed by light emissions or light transmission. The plate comprises an upper plate forming the side walls of the sample wells, the side walls being opaque so that light cannot be transmitted between adjacent wells through the side walls, and a lower plate forming the bottom walls of the sample wells, the bottom walls being transparent to allow the transmission of light therethrough. Bands of opaque material are provided within the lower plate and surrounding each well to block the transmission of light between adjacent wells through the lower plate.

Abstract: A system for in-situ measurement of the radioactivity of multiple samples while the samples are in a multiple-well sample tray, with a scintillator in each sample-containing well for producing light pulses in response to radiation from the respective samples. Multiple photomultiplier tubes are positioned adjacent to the sample wells containing the scintillator for simultaneously measuring the radioactivity of multiple samples with only a single photomultiplier tube sensing the scintillations from each well and converting the sensed scintillations into corresponding electrical pulses. The electrical pulses from each photomultiplier tube are processed to discriminate between pulses attributable to sample events within the wells and pulses attributable to non-sample events such as photomultipler tube noise.

Abstract: A low-level liquid scintillation measurement system for counting sample optical events resulting from the radioactive decay of a constituent of a sample to be measured while reducing the counting of background optical events which are optical events produced by background radiation and which create electrical pulses other than pulses representing a sample optical event.

Abstract: Apparatus for generating hydrogen by the electrolysis of water comprising an electrolytic cell having a cathode and an anode separated by a solid electrolyte, an electrical power supply connected to the cell for applying a voltage across the cathode and anode, a water reservoir connected to the cell for supplying water to the anode side, a hydrogen-water separator connected to the cell for receiving hydrogen and water from the cathode side and separating the hydrogen from the water, and a water return line connecting the hydrogen-water separator to the water reservoir for returning water to the water reservoir whereby the water is recycled to the anode side. A float valve in the upper region of the hydrogen-water separator closes the hydrogen outlet in response to an increase in the water level in the separator to the level of the hydrogen outlet, to prevent water from entering the hydrogen outlet in the event of a malfunction.

Abstract: An improved method and apparatus is provided for performing high sensitivity fluorescence measurements. A liquid sample contained within a cuvette is exposed to exciting radiation in such a way that the radiation is introduced directly to the sample and is restricted from reaching the container walls. The sample container is in the form of a cylindrical cuvette provided with reflector means on the bottom so that any unabsorbed exciting radiation reaching the cuvette bottom is reflected back through the sample solution. Fluorescent radiation emitted by the sample is collected by an ellipsoidal reflector which substantially surrounds the sample container and focuses radiation incident thereupon onto a small area from which it is efficiently sensed by a photodetetor. The optical arrangement realizes significantly improved signal-to-noise and signal-to-background ratios.