Abstract: A thin-wall centrifuge tube having multiple chambers for use in fluid sample investigation with an ultracentrifuge. More particularly, the multiple chamber ultracentrifuge tube can be used, for example, in lipoprotein separation. The ultracentrifuge tube may have two or more separate chambers which, subsequent to centrifugation, can be sealed from each other to retain the separated constituents of the sample under investigation. The chambers in the tube are joined by a constricted area which permits fluid communication between the chambers. The tube is designed to be used in conjunction with a support spacer adjacent the constriction in the tube so that the tube is properly supported during high speed centrifugation.

Abstract: A device for starting and operating gas discharge tubes including a DC-to-AC inverter which generates a low voltage or a high voltage at an output thereof in response to first or second input signals, respectively. The output of the inverter is connected to a gas discharge tube and sensing means generates a signal proportional to the current flow through the tube. Suitable means provides a trigger or synchronizing signal to a driver. The driver, responsive to the sensed output signal and the trigger or synchronizing signal, generates a drive signal synchronized with the trigger or synchronizing signal and having a duration inversely related to the magnitude of the current flowing through the gas discharge tube. A high voltage switch applies a second input signal to the inverter in response to the drive signal to provide a decreasing high voltage duration during successive cycles of the inverter as the tube begins to conduct current.

Abstract: A device for handling and washing beads. The device is attachable to a test tube rack and includes a frame, a containing slide, and a capture slide. By manipulating the slides in various combinations of positions the beads may be added to, removed from, or separately washed apart from test tubes in the rack. Complete and easy washing of the beads may thus be accomplished.

Abstract: A method for driving a stepper motor. The method includes varying the width of the high level drive impulses of a bi-level drive system based on the desired speed to be achieved by the stepper motor. A microprocessor is used to vary the pulse width.

Abstract: Apparatus for transporting elongated sample holders in a sample holder storage compartment past an operating station at which sample tubes contained in the sample holders may be removed and then returned to the sample holders. First and second parallel conveyors on opposite sides of the operating station drive the holders toward and away from the operating station. A lateral drive system engages the holders in longitudinal stop positions at opposite ends of the conveyors and drives them laterally between the conveyors to lateral stop positions, one of the holders during lateral movement being driven into and away from an operative position at the operating station. Encoded labels are displayed on each sample holder for indicating the incremental spacing between the sample tubes carried in the sample holder.

Abstract: Apparatus for establishing a "home" position for a load element driven axially along the lead screw. A position sensor includes a first sensor element attached for axial travel with the load element and a second sensor element attached for rotation with the lead screw. The pair of sensor elements is operatively aligned at a predetermined relative axial and rotational position establishing the "home" position.

Abstract: A pH electrode which is capable of withstanding repeated exposures to sterilizing temperatures. An electrode body having a pH sensing member is at least partially filled with a bed of electrochemically inert particles. After an internal reference is inserted into the particle bed, the bed is injected with a quantity of electrolyte which is sufficient to establish continuity between the sensing member and the internal reference, but which is not sufficient to produce destructive internal pressures when the electrode is subjected to sterilizing temperatures. The electrode is completed by forming a seal between the electrode body and the internal reference.

Abstract: An assembly for sealing the access passageway to a detector chamber in a scintillation counter instrument. The seal is designed to prevent the entry of any exterior light or environment that could affect the counting or scintillation process when a sample is positioned in the detector chamber. The sealing mechanism operates in conjunction with the scintillation instrument's flexible transport or elevator mechanism that moves a sample containing vial into the detector chamber. A plurality of rotating blades engage the elevator mechanism to form the tight seal. Included in the arrangement is a redundant system to provide a dual sealing capability. The sealing mechanism operates in conjunction with the flexible transport member which allows itself to be centered by the sealing mechanism to achieve the required light seal.

Abstract: An ultracentrifuge rotor comprising a body portion formed as a bowl with a central open chamber defined by a thin, cylindrical wall extending from a supporting base and a plurality of nested rings of filament windings surrounding the cylindrical wall for strengthening and stiffening same. The nested rings result in a uniform filament density throughout the ring assembly.

Abstract: An electro-optic display device having at least two separate compartments for receipt of electro-sensitive material that is utilized in the formation or establishment of a display symbol as a result of an electrically imposed field. One compartment in the display contains the electrodes which form the various segments of the variable symbol to be displayed. The other compartment is the background area that will contrast visually with the segment portions that make up or establish the symbol to be displayed. The choice of material makes the background compartment optically equivalent to the portion of the symbol compartment that is not displaying a particular symbol. The electro-optic device preferably has a liquid crystal material with a dye to create a light absorption type of electro-optic display rather than a light modulation type of display. This invention allows dye displays that normally portray light characters on a dark background to be portrayed as dark characters on a light background.

Abstract: Balancing bosses integrally forged in a centrifuge rotor. The plurality of balancing bosses in the rotor establish noncritical areas in the rotor for machining to accomplish the precise balancing necessary for high speed ultracentrifugation. The balancing bosses are located away from the high stress periphery of the rotor so that machining a portion of the bosses for balancing purposes will not degrade the integral strength of the rotor.

Abstract: A high pressure valve for control of the injection of a sample into an analyzer system such as an amino acid analyzer with liquid column chromatography. The valve is designed in such a manner that no rinse solution that is used to cleanse the system after the injection of a particular sample will enter the liquid column. The valve operates in two positions and requires a minimum of movement between the two positions. In one position the valve allows for the injection of the sample into the liquid column. In the second position the valve allows for the entry of only a buffer solution into the liquid column and blocks the entry of any rinse solution that may flow through the system for cleansing after the injection of the sample. No residual rinse solution is allowed to remain within the valve prior to injection of either a sample or a buffer material into the liquid column.

Abstract: An apparatus for gently transferring delicate produce from a supply conveyor into a dry storage bin. The discharge head of the apparatus has a reversible delivery board which directs and uniformly stacks the produce within the bin without bruising the produce. The transfer apparatus utilizes a series of opposed brushes on a parallel conveyor arrangement to gently support and transfer the produce to the bin. The discharge head and the bin move relative to each other in both the horizontal and vertical planes to provide uniform layers of produce and to adjust for the increasing layers in the bin.

Abstract: A device for use with variable electrical components such as potentiometers to provide not only an independent means adjacent the control knob to lock the knob in a fixed position, but also to provide variable amounts of drag on the knob to enhance more precise and accurate control of the knob. The locking device is positioned between the controlled component and the control knob. The locking device can be moved to a plurality of positions adjacent the control knob to vary the amount of drag on the control knob.

Abstract: An insert for use with swinging bucket rotors at the interface between the swinging bucket and the rotor arm trunnions which pivotally support the bucket. The insert is designed to decrease the friction between the swinging bucket and the support trunnions.

Abstract: In a multilayer gas-discharge display panel of the type including a plurality of character blocks, each including a plasma supply reservoir section, a control anode section, and a display section, such sections being arranged in a plurality of parallel, gas-filled columns defining a display matrix, the supply reservoir providing a source of ions which are selectively conducted by the control anodes to the display section, a voltage being applied to the display section to initiate a gas breakdown in those columns which have had ions conducted therethrough by the control anodes, an improved display section is disclosed comprising a transparent, insulating plate extending across the front of the panel, perpendicular to and covering all of the columns, a transparent electrode covering the front surface of the plate, on the opposite side of the plate from the supply reservoir and the control anodes, and means for applying voltage pulses of alternating polarity to the electrodes to create a flashing discharge in ea

Abstract: A centrifuge rotor assembly having a resilient liner with at least two separate chambers. Fluid communication between the separate chambers is automatically controlled in response to centrifugation operation of the rotor. When the rotor is stationary, the liner assumes a first position within the rotor where an annular chamber is sealed from a central chamber. When a fluid sample is placed within the liner of the rotor and the rotor is subjected to centrifugation, the centrifugally induced forces of the fluid mixture shift the liner to a second position, opening the sealed condition between the central and annular chambers to permit fluid communication between the respective chambers. When the centrifugation operation has been completed and the rotor returns to its stationary position, the inherent resilient structural characteristics of the liner automatically re-establish the seal between the respective chambers.

Abstract: A rotor having a plurality of swinging carriers designed to receive specimen samples for subjection to centrifugation. The carriers are pivotally mounted to a rotor frame in such a manner that the generally flat support faces of each of the carriers assumes a parallel orientation with respect to the rotational axis of the rotor during operational speeds of the rotor. When the rotor is not operating, the support surfaces of each of the carriers assumes the perpendicular or acute angle orientation with respect to the rotational axis of the rotor. In order to overcome any resistive frictional forces which may be generated at the interface between the rotor frame and the pivoting carrier, the pivot axis of the carrier is shifted from the central or center of gravity plane of the carrier to ensure that the support surface of the carrier will positively assume its proper parallel orientation with the rotor spin axis.

Abstract: A pivotal carrier for use in centrifuge rotors wherein the ends of the rotor carriers are adjustable to vary the supporting or receiving surface area in the carrier to accommodate various sized tube racks which may be used in the centrifuge rotor. Holding members in opposite ends of each carrier are movable to a plurality of positions to symmetrically position the tube rack within the carrier to maintain dynamic rotor balance.