Abstract: Method and apparatus for controlling the angular velocity of a centrifuge tube containing a solute and a solvent to obtain desirable sedimentation behavior and/or diffusion behavior of the solute within the tube during centrifuge operations. In one embodiment, the angular velocity is maintained at a near-maximum value until just before precipitation of a solute component is reached within the tube. The tube angular velocity is then reduced as a function of time so that critical precipitation is approached but never occurs in the tube as the centrifuge process continues. In other embodiments, the net flux of solute particles into a given volume element of the centrifuge tube, or the ratio of net fluxes of two or more solutes into a predetermined volume elements, is caused to be a prescribed function of time. One application of this method is minimization of the time required to obtain a desired density gradient separation by a centrifuge process.

Abstract: A resealable conduit is used to remove or add fluid to a closed system without coring or contamination of the fluid. The conduit can include funnel-shaped guide means, duck bill valve means and beveled tip puncturing means. A conduit resting angle of less than about five degrees can be achieved. A tip bevel angle between about ten and twenty degrees is preferred. The beveled tip can have a rotated or twisted blade surface extension. A blade surface extension formed with a ninety degree rotation of the blade surface is preferred. Alternately, the puncturing means can include a needle point or a flat cutting surface.

Abstract: A trifunctional conjugate is provided having three chemical moieties, attached through a spacer moiety. At least two of the chemical moieties are relatively small molecules, usually less than about 7,000 Daltons in size. The spacer moiety is selected to impart certain steric properties to the conjugate. In one embodiment, the binding of a macromolecular specific binding partner to one of the chemical mouths sterically inhibits the binding of a different macromolecule to another chemical moiety. In another embodiment, the binding of a first chemical moiety to a macromolecule restricts the subsequent binding of a second chemical moiety to a proximate location on the same macromolecule.

Abstract: A system for analyzing a chemical reaction provides control of the temperature and volume of the reagents to improve the accuracy and precision in quantitative measurements of specific proteins and other immunochemistries in body fluids. The reaction occurs in a cuvette within a nephelometric optics module. A sensor senses the temperatures of reaction buffer liquids as they flow into the cuvette, and a heat exchanging device increases or decreases the temperatures of the buffer liquids. A control circuit responsive to the temperature sensor controls the heat exchanging device to maintain the temperature of the buffer liquids and the cuvette within a selected temperature range. The system may also include a sample pickup station, a sample probe for withdrawing a selected sample from the sample pickup station, a sample preparation station, and a sample transport for carrying said sample from the sample preparation station to the reaction cuvette.

Abstract: A reciprocating shaft which dynamically self-corrects angular misalignment between the shaft and its drive mechanism during reciprocative motions. A thrust bearing is utilized to take up axial loading of the shaft to allow the shaft to freely rotate on its supports.

Abstract: A mailing device for etiologic agents and/or biomedical materials is disclosed. The mailing device comprises a front panel joined to a back panel, the back panel being longer than the front panel. Three sides of each panel are sealed together, preferably by an adhesive, most preferably by heat sealing, such that an opening to an internal region is created, said opening defined by the top, unsealed portion of the front panel, and the top unsealed portion of the back panel which exceeds the height of the front panel. The region of the back panel extending above that of the front panel is referred to as a "flap" or "flap region". The flap region includes means for folding the flap along a substantially parallel line to said opening, said line being located above the opening, preferably from between about one-fourth to about one-half of the distance of the flap upwards from said opening and most preferably about one-fourth of the distance of said flap upward from said opening.

Abstract: A redundant safety lock for securing a centrifuge lid in its closed position. The lock includes a disc having an aperture through which a striker on the lid can be inserted in an unlocked position. The disc is rotated to a locked position such that the striker cannot be withdrawn through the aperture to open the lid. The weight distribution of the disc is substantially symmetrical about its center of rotation. The disc is therefore less susceptible to dislodging form its locked position upon perturbation from shock experienced.

Abstract: Disclosed herein is a methodology for analyzing isoenzymes using capillary zone electrophoresis ("CZE") techniques. Briefly, an isoenzyme-containing sample and a substrate capable of being catalyzed by said isoenzyme into a reaction product are introduced into a capillary column comprising a buffer. Most preferably, the buffer contains the substrate prior to introduction of the sample into such substrate-buffer. CZE separation techniques are applied to the column such that the isoenzymes are separated from each other into discrete zones. The separation techniques are terminated such that product is rapidly generated by the catalytic conversion of substrate by the isoenzymes, and accumulated, within each discrete zone, followed by detection of product. Information regarding the relative distribution of the isoenzymes can be derived from the relative distribution of the product.

Abstract: A detection and quantification technique for radioisotope labeled components separated in a capillary separation channel. The section of the separation channel containing the separated components is significantly cooled to substantially eliminate diffusion of the components while detection is being carried out. The section can be frozen and autoradiography technique or solid state electronic imaging technique can be utilized to obtain an image representative of the relative amounts of separated components.

Abstract: An automated multi-purpose analytical chemistry processing center and laboratory work station having a movable table for supporting microtiter plates and other fluid receptacles, a movable arm, and a modular mobile pod affixed for reciprocal movement along the arm. The workstation combines into a single programmable system the capabilities for automation of a wide range of bioanalytical procedure including, not only sample pipetting, serial dilution, reagent additions, mixing, reaction timing and similar known manual procedures, but also programmable spectrophotometric measurements and other physical parameters, further processing based on these measurements and automatic data recording. The work station is adapted to transfer, dispense, and aspirate liquid from one location to another automatically in accordance with user programmed instructions.

Abstract: External markers and method for the identification of protein-and-peptide-containing samples utilizing capillary electrophoresis analysis. As disclosed, at least two external markers are added to the sample: one of the markers is a neutral charge species and one of the markers is an ionic species. Dimethylformamide is a preferred neutral charge species and benzoic acid is a preferred ionic species. Identification of constituent species is determined by comparing the migration ratios of the constituent species with migration ratios for each constituent species member.

Abstract: The sample injection cell comprises a body and a bore through the body for receiving a probe to pass fluid sample into the bore. A transverse passageway into the body permits a diluent to enter the bore and be mixed with a sample in a predetermined ratio and be dispensed directly into the flow cell. The diluent simultaneously washes the probe when the probe is located in the bore. A waste basin forms part of an integral unit and is adjacent the bore so that fluid from a flow cell can enter the waste basin and then exit under gravity to a waste drain.

Abstract: An automatic chemistry analyzer includes a flow cell mounted so that flow through the cell and tubing connected to the cell is visible from the front of the housing. The electrolytes to the cell are removably plugged into the cell from their rear. The probe aspirating sample flud into an injection cell is simultaneously washed by diluent and the diluent mixes with the fluid sample. Waste fluid from the flow cell is fed to a basin which then feeds under gravity to a waste drain. A ratio pump is formed by selected syringes which are band driven to deliver accurately prerequisite volumes of reagents to the flow cell. The solution ground to the system is on the inlet line for sample adjacent the entrance to the flow cell of fluid thereby minimizing electronic noise. Only two motive means are necessary, one to effect horizontal and rotational movement of the sample tray, and a second to effect vertical motion of a crane mounted probe operative between sample cups and an injection cell.

Abstract: A salt bridge for a flow cell which includes a porous bridge element between fluid flow in the flow cell and in an internal reference fluid flow. The bridge element is surrounded by a body with a bore into which different tubes are located about the porous element. A cylindrical anchoring tube adjacent one end of the body is screw threaded into an aperture in the wall of the flow cell so that self-alignment of the salt bridge in the flow cell is effected. The salt bridge provides a conductivity path between the two flow paths without introducing another potential.

Abstract: A direct current power supply which incorporates an alternating current circuit segment so as to enable the use of a reactive component as an impedance limiting circuit element. The alternating current is produced by pulse width modulation regulation of raw direct current and DC to AC inversion. A feedback circuit is provided to regulate the pulse width modulation in accordance with the direct current output by the power supply so as to obtain a desired output current.

Abstract: A method of measuring and compensating stray light in absorbance analysis that use a multiple element array detector wherein one or more of the elements of the diode array are utilized to detect stray radiation in the absence of primary radiation including higher order diffracted radiation. In one aspect, the atmosphere is used to filter all primary radiation below a particular wavelength so that one or more array elements corresponding to detection below such wavelength can be dedicated to the detection of only stray radiation. Detection of higher order diffractions can be prevented by dividing the total spectrum into intervals and detecting these intervals in sequence. In another aspect, a diode array is designed to include additional elements along one side of the array outside the exposure of the primary radiation for the sole purpose of detecting stray radiation.

Abstract: A means of sealing a centrifuge tube which makes use of the hydrostatic pressure of the sample solution contained in the tube to perfect a tight seal during centrifugation. The filler stem is plugged with a plug which is supported in the rotor cavity. The hydrostatic pressure forces the filler stem against the plug to effect a seal with a sealing force which is dependent on the hydrostatic pressure which is in turn dependent on the centrifugal force on the sample solution.

Abstract: An automated multi-purpose analytical chemistry processing center and laboratory work station having a movable table for supporting microtiter plates and other fluid receptacles, a movable arm, and a modular mobile pod affixed for reciprocal movement along the arm. The workstation combines into a single programmable system the capabilities for automation of a wide range of bioanalytical procedures including, not only sample pipetting, serial dilution, reagent additions, mixing, reaction timing and similar known manual procedures, but also programmable spectrophotometric measurements and other physical parameters, further processing based on these measurements and automatic data recording. The work station is adapted to transfer, dispense, and aspirate liquid from one location to another automatically in accordance with user programmed instructions.

Abstract: A monochrometer having a stray light trap which substantially directs stray light away from light of wavelength of interest and/or absorb the stray light so as to substantially reduce the stray light component in the light of interest. The monochrometer has internal surfaces each having one of several optical characteristics.

Abstract: Method and electrolyte buffer useful in the analysis of samples comprising glycoproteins by capillary zone electrophoresis. The buffer comprises at least one agent capable of complexing with sugar moieties of glycoproteins. The buffer preferably further comprises at least one pH modifier. An embodiment of the buffer comprises boric acid as the complexing agent and sodium hydroxide as the pH modifier.