Abstract: Output current hysteresis exhibited by a multiple-dynode photomultiplier detector is reduced by inactivating one or more of the dynodes by shorting to the detector anode, and operating the detector with the reduced number of active dynodes while retaining the anode as the output current supply terminal.

Abstract: A centrifuge rotor and sample containers for reorienting gradients and separating the components of a sample. The rotor contains a plurality of cylindrical recesses equally spaced about its rotational axis. The recesses are open at the top and have a concave hemispherical bottom. A cylindrical plug member is positioned in each of the recesses, and the lowermost end of the cylindrical plug member is formed in the shape of a concave hemisphere. A sample container in the shape of a hollow sphere is positioned between the hemisphere of the cylindrical plug member and the hemisphere of the recess bottom, and means are provided to retain the cylindrical plug member in the recess. The symmetry of the hemispherically shaped sample container is advantageous for minimizing any disturbance to a gradient during reorientation. In another embodiment, a centrifuge rotor is provided which is adapted for fixed angle centrifugation with hemispherical sample containers.

Abstract: A centrifuge rotor having an internal chamber in which are mounted a plurality of swinging centrifuge tubes containing fluid samples. Located within the rotor chamber is a liquid support medium which minimizes the amount of stress experienced on the centrifuge tube and at the pivotal junction of the tube with the rotor. The unique arrangement of having the buoyant force of a liquid within the rotor provides support to the tubes when the tubes have pivoted to their position during operational speed. The liquid support is designed to reorient in response to centrifugation in order to automatically provide the buoyant force to the tube during centrifugation and thereby reduce or greatly minimize the strength necessary in the mechanical design and construction of the support elements for the swinging tubes or containers.

Abstract: A creatine kinase reagent of the type comprising a buffer, creatine phosphate, adenosine diphosphate, D-glucose, hexokinase, glucose-6-phosphate dehydrogenase, a thiol compound, magnesium ion, adenosine monophosphate, and a coenzyme selected from a group consisting of nicotinamide adenine dinucleotide, nicotinamide adenine dinucleotide phosphate, and mixtures thereof. The reagent is characterized in that it further comprises an effective amount of an enzyme selected from a group consisting of phosphogluconate dehydrogenase and phosphogluconate dehydrogenase (decarboxylating).An electrophoretic technique for assaying the relative distribution of creatine kinase characterized in that the above reagent is employed therein.

Abstract: A sealed bowl rotor having a transparent lid for easy visual checking of rotor contents. The lid has sealing means that automatically creates a seal which prevents the escape of liquid samples from within the rotor when the lid is placed on the rotor. The rotor design prevents the application of any possible hydraulic loading on the transparent lid. The installing/removing mechanism on the lid provides the capability for removal of the lid after the centrifugation run without disturbing the contents of the samples within the rotor.

Abstract: A method for making a thin wall centrifuge tube using an injection blow molded process to achieve not only uniform thickness of the tube, but also uniform or homogeneous material properties throughout the tube structure. The unique application of this process includes the making of a preform mold which retains its molten stage on a transferrable core pin that is received at a second stage, where the final configuration mold is placed around the core pin. The blow molding stage operates in conjunction with the molten preform to create the high strength centrifuge tube with uniform material properties.

Abstract: A transparent tube for use in the cavity of the rotor of a high speed centrifuge. The tube is penetrable at its bottom end by a needle of a hypodermic syringe. The tube is open at the top and has a rounded bottom with an opening forming a passageway therein. A recess forming a shoulder co-axial with the passageway is provided both on the inner side and the outer side of the tube. A resilient plug having flanges at each end provides a tight fitting closure for the passageway and recesses.

Abstract: Circuit for starting and operating a gas discharge lamp. The circuit includes a resonant circuit having a high Q during both starting and operating conditions of the lamp, thereby permitting a high lamp operating voltage to be obtained from a relatively low voltage power supply. The circuit comprises a power supply, an inductor-capacitor series-resonant circuit connected across the power supply terminals, and a lamp circuit connected in parallel with the capacitor of the series-resonant circuit, wherein the lamp circuit comprises a second capacitor connected in series with a gas discharge lamp.

Abstract: An electro-mechanical package is disclosed which includes an LCD and an IC chip mounted on opposite sides of a PC board by common package-retaining means, which includes posts extending through the PC board and a clip member that latches onto the ends of the posts to retain the package in assembled position. The latching action is resilient and permits non-destructive disassembly.

Abstract: A light scattering photometer including a rotating segmented mirror intercepting light from a laser source and alternately directing the light into a sample zone along an optical axis in first and second opposite directions. A mask annulus coaxial with the optical axis intercepts light scattered from the sample in an incremental angle .DELTA..theta. at a selected angle .theta. with respect to the axis. As the direction of sample illumination alternates, the annulus alternately intercepts forward scatter and back scatter of light from the sample at angles .theta. and 180.degree.-.theta., respectively, and passes the forward and back scatter in alternate succession to a detector. The detector output signal is demodulated to derive near-simultaneous forward and back scatter measurements from the sample. The photometer permits measurement at small values of .theta. approaching 0.degree. and hence permits near-simultaneous scatter measurements at forward and back scatter angles spaced by an angle approaching 180.

Abstract: An electrical device consisting of a package 10 comprising a base 11 and a lid 15 and an operation element 17 contained within the package. A particle getter 19 is disposed on the lid 15 for entrapping and retaining foreign particles contained within the package 10. A method for protecting the operational element 17 of such an electrical device from the particles is disclosed wherein a polysiloxane material is partially cured with less than about 9 parts of a suitable curing agent to 100 parts of polysiloxane resin to a non-flowing, particle entrapping and retaining condition and the partially cured material is secured within the package.

Abstract: The present invention provides a centrifuge rotor adapted for continuous separation of specific particles from mixed populations thereof by a process of centrifugal elutriation. In the rotor, elutriation cells abut a central spindle having fluid carrying means, and thereby eliminate intermediate conduits and seals therefor, thus reducing the likelihood of leakage because of faulty aperture registration or failure of the sealing means.

Abstract: A T.sub.3 uptake polarization fluoroimmunoassay where a sample is assayed by contacting a serum sample with T.sub.3 to form a solution, contacting the solution with a separating agent and incubating the same, separating T.sub.3 bound to the separating agent from the serum sample, contacting the T.sub.3 bound to the separating agent with an antibody against T.sub.3, incubating and separating the agent-anti-body combination, separating free anti-body and contacting the free antibody with fluorescent labeled T.sub.3 and fluorometrically measuring the fluorescence polarization.

Abstract: A polarization fluoroimmunoassay for T.sub.3 or T.sub.4 thyroid hormones where a serum sample is assayed by contacting the sample with a base to denature the thyroxine binding globulins and thereby form a solution, incubating the solution, contacting the solution with a separating agent and separating bound thyroid hormone from the serum, contacting the separating agent with bound thyroid hormone with an antibody against the thyroid hormone, incubating the separating agent-antibody combination, separating free antibody and thyroid hormone bound antibody from the separating agent, contacting the free antibody with fluorescent labelled thyroid hormone and measuring the fluorescence polarization as an indication of the thyroid hormone in the sample.

Abstract: In accordance with the present invention, there is provided an air driven centrifuge having an access door to a rotor chamber housing a rotor seat and a rotor having a plurality of turbine flutes formed in the underside thereof. Air jet means in the rotor seat are provided for supporting and spinning the rotor on an air cushion in the chamber. Means are provided to prevent the opening of the access door when pressurized air is supplied to the air jets, and means are provided to delay for a predetermined period, the opening of the door after the supply of pressurized air to the air jets is discontinued.

Abstract: A stable blood serum conjugated bilirubin reference composition characterized in that the composition possess a pH of from about 8.2 to bout 9.2 and comprises (a) a sulfhydryl compound in an amount sufficient to enhance the stability of the conjugated bilirubin and (b) a chelating agent in an amount sufficient to bind all the metals present in the blood serum moiety of the composition. This blood serum conjugated bilirubin composition when stored in a gas impervious vial under an inert atmosphere has an excellent shelf life.

Abstract: The present invention is directed to a transparent safety cover for sealing the mouth of a pivotally mounted bucket of a centrifuge rotor. The cover has a first surface configured to make telescoping engagement with the sidewall of the rotor bucket. A shoulder adjacent the first surface abuts the top of the bucket to limit the length of engagement. The first surface has an annular groove containing a resilient O-ring which makes a seal between the cover and the bucket. In the upper portion of the cover, there is a raised dome-like structure with a circular aperture at the top. The aperture has inverted conical walls and is sealed by a movable, resilient, sealing plug. The plug has a tapered body and at the lower portion thereof, are wall gripping means for retaining the plug in a raised, unseated, position. With the plug in the unseated position, the bucket is vented to the atmosphere permitting telescoping movement of the cover with respect to the bucket.

Abstract: A device and method for washing an object in a receptacle. The device includes an end portion introducible into and cooperative with the receptacle to define a substantially enclosed space containing the object to be washed. The fluid is introduced into and aspirated from the substantially enclosed space such that the object is movable in the fluid between the end portion and the receptacle.

Abstract: A rotor seat which automatically adjusts its position with respect to the rotor in response to air flow levitation air entering between the rotor and the rotor seat. The central portion of the rotor seat which has a mating design with the design of the bottom of the rotor is free to move in a vertical direction toward or away from the rotor in response to the flow of air. The rotor seat maintains its optimum position relative to the rotor, allowing the rotor to decelerate in a stable manner.

Abstract: A membrane for use in the determination of calcium ion concentration in an aqueous solution, the membrane being of the type comprising a calcium ion selective component and a carrier material.