Abstract: A particle counter, of the type utilizing a Coulter(R) type aperature and a suction flow path downstream from the aperture, has a pair of electrodes on both sides of the aperture. A current is provided from the downstream electrode to the upstream electrode and pulses in the resulting voltage across the aperture are monitored to detect the passage of blood cells through the aperture. A grounded electrode is placed in the downstream flow path at a position near the package panel to isolate the cell counter from external electrical noise signals. An isolated high input inpedance amplifier is coupled to provide the monitored voltage to an inserted electrode positioned between the downstream aperture electrode and the grounded panel electrode. Because the inserted electrode and downstream electrode are then at the same voltage, no current flows through that portion of the flow path.

Abstract: An isotonic multipurpose blood diluent, and a method for use of this diluent with a weak lysing reagent system which is especially suitable for routine enumeration of traditional hemogram values, and also the determination of lymphoid-myeloid populations of leukocytes, particularly in automatic particle counting systems.This blood diluent is capable of affording accurate, reproducible test results. It is an osmotically balanced aqueous solution of preselected pH containing Procaine hydrochloride for maintaining erythrocyte morphology during operation, N-(2-acetamido)iminodiacetic acid (ADA) as a blood cell stabilizing agent, and bacteriostatic agents including sodium 1-hydroxypyridine-2-thione, and dimethylolurea which, together with the ADA, allow preferential determination of myeloid-lymphoid leukocytes, and other hematological values.The lysing agent is a mixture of an aqueous solution of at least one quaternary ammonium salt having surface active properties, and an alkali metal cyanide.

Abstract: A liquid sampling, metering and transfer valve assembly for providing plural dilutions of a single liquid sample comprising a pair of outer stationary elements sandwiching a rotatable element, the rotatable element carrying precise volume segmenting passageways, the outer elements carrying counterpart passageways for communicating to the exterior of the valve assembly, one outer element carrying loops each for storing a precise volume of diluent and the other valve elements carrying through passageways for communicating to and from said respective loops. A continuous body of sample is introduced into the valve assembly along a path through a pair of the segmenting passageays and a pair of aliquot portions isolated from said parth. The rotatable element is operated to direct one aliquot along with the content of one loop to an exterior location for mixing. The other sample aliquot is retained.

Abstract: A rotary liquid metering and transfer valve assembly for a diluting system which includes a pair of stationary valve disc elements sandwiching a central, rotatable valve disc element, said disc elements being coaxially aligned and mounted on a spindle. One of the outer stationary elements has a first external loop secured thereto, said loop having a precise interior volume. An aspirator probe is secured to the other of said stationary elements. The central element has formed therein an axial segmenting passageway having a precise interior volume. A second external loop is secured to the center element. The second loop extends outwardly, preferably radially, of said element and has a precise interior volume. Appropriate interior passageways are provided in the outer elements for directing a liquid sample in a continuous path through the valve assembly, the path including the one segmenting passageway and the first and the second external loops.

Abstract: Bellows pump and actuating apparatus for automatically aspirating biological sample fluid material into and through an aspirating probe from a source of fluid sample material, into and through a sample segmenting valve for passage through a counting device. A plurality of bellows members, each having an axis of compression and expansion, has one end mounted on a fixed member. Timing and stroke members are provided for actuating movement of the other end of the bellows members, which are free to be moved parallel to their axis. A positioning member positions the timing and stroke members coaxially of the bellows members at preselected times. A drive member moves the timing and stroke members parallel to the axis of compression and expansion of the bellows members. Photo-optical indicating members, cooperating with the positioning member, interrupts the drive to the positioning member when the timing and stroke members are coaxially aligned with the bellows members.

Abstract: An improved procedure for statistically evaluating the performance, precision and/or accuracy, of at least one analytical instrument in a pool of like or substantially like instruments by comparing the performance of the one instrument located in one laboratory with the performance of like instruments in other laboratories. The procedure includes the step of quantitatively analyzing a reference or control specimen of known constituents by each instrument in the pool and collecting the resultant data from the one instrument in the pool and of the pool instruments. The mean data from the one instrument and of the pool instruments are mathematically correlated in a series of statistical equations for computing a novel, sensitive index known as the "Instrument Performance Index" or IPI.

Abstract: Automatic biological sample mixing apparatus for use in flow cytometry, wherein a sample container is secured loosely at its top by means of a multi-reagent dispensing head; and the container is mounted at its bottom on a resilient support disposed on an elliptically rotated member, to cause reagents introduced into the container to be thoroughly mixed with a sample in the container in a fast, efficient, gentle, and accurately repeatable manner.

Abstract: For use in a tilt action valve for dispensing a pressurized viscous product, in which a grommet is held by a mounting cup and secures the valve stem and body, product leakage between the grommet and valve stem is minimized by forming in the grommet a pocket which fills with the dispensed product and then lies tightly against the valve stem. The pocket causes the valve and grommet to be tilted with easier control. The pocket's operation simplifies the construction of the grommet and valve body, thus permitting dimensions which enable cheaper parts costs and assembly.

Abstract: Water soluble xanthylium derivative substrates of rhodamine 110 and rhodol permit spectrophotometric and fluorescent measurements of trypsin-like enzymes without the addition of organic solvent additives and/or special water solubilizing agents. These novel substrates exhibit increased sensitivity for determining low levels of activity of trypsin-like enzymes such as proteolytic enzymes, cofactors, activators, antiactivators, and inhibitors. These substrates can be substituted for fibrinogen to monitor the pathways of blood coagulation.

Abstract: Particle produced pulses are evaluated on an individual basis for shape symmetry, with significantly asymmetric pulses, becoming subject to editing, i.e. exclusion. Pulse symmetry is determined by measuring the areas under the pulse before and after the first pulse amplitude peak and then by comparing those pulse areas with respect to pre-established limits which are not based upon any of the pulses then being evaluated.

Abstract: A circuit, which is useful to provide data needed to measure the electrical opacity of a particle, for instance a blood cell, passing through a Coulter type transducer, includes a current source for providing a conventional d.c. current through the sensing aperture of the transducer, as well as an oscillator for providing a high frequency current through the aperture. The oscillator includes an active device and a resonant circuit, and the aperture is coupled in parallel with the resonant circuit of the oscillator. The oscillator can be any type of oscillator, such as a Hartley oscillator. As a particle passes through the aperture, the resistance of the aperture increases, which in turn, increases the Q of the oscillator circuit, whereby the oscillator output signal is amplitude modulated in accordance with the increased Q. This amplitude modulated signal can be detected to provide a value based on the high frequency reactance of the particle being detected. The change in d.c.

Abstract: A debris detector for a particle counter, such as a blood cell counter, of the COULTER (R) type. When a particle, or transient debris, passes through the sensing orifice of the particle detector, a voltage pulse occurs; whereas, when debris lodges in or against the orifice of the particle detector, a d.c. voltage shift occurs. The voltage at the orifice is capacitively coupled to an amplifier and the output of the amplifier is integrated. The capacitor coupling the orifice voltage to the amplifier causes an undershoot voltage at the trailing edge of each particle or transient debris pulse, such that a zero average voltage is applied to and, hence, from the amplifier for each voltage pulse. The integrated voltage is applied to a voltage comparator to provide an output signal therefrom whenever the integrated voltage exceeds a reference voltage. The comparator output signal is provided to a delay circuit having a delay related to the time required for a particle to pass through the COULTER detector orifice.

Abstract: A coiled line tangle inhibitor which comprises a flexible sheath that encases a relatively loosely coiled line to prevent it from tangling with itself as well as tangling with adjacent lines, which also would be sheathed by this invention. The sheath, although very flexible to allow free movement of the coiled line and any attached tool, has sufficient stiffness and diameter so that the coiled line can slide through an open end of the sheath with ease, but without self-meshing, as the line is extended and retracts in normal use.

Abstract: Apparatus for detecting contaminants, including emboli, in a blood sample prior to blood cell analysis, wherein fluid density sensors are arranged on opposite sides of a fluid segmenting valve to provide electrical signals indicative of the degree of optical opacity of the fluid flowing through the sensors. The derived signals are compared against a diluent reference level signal to provide resultant signal outputs indicating the presence or absence of emboili or other contaminants within the segmented portion of fluid.

Abstract: This invention describes a reagent system, including saponin in a lysing reagent and a rapidly active cross-linking agent such as glutaraldehyde as a fixing reagent, which reproducably affects whole blood to cause the red blood cells to stromatolyze and modifies the leukocytes to generate data to define four distinct clusters for detection and classification by flow analysis instrumentation. The clusters represent the four major leukocyte types found in blood: lymphocytes, monocytes, neutrophils and eosinophils, thus providing a method of leukocyte differential analysis. The parameters used for the leukocyte classification include combinations of two or more of DC (Coulter) volume, high frequency (RF) size, opacity (RF size/DC volume), light scatter at various angular ranges, and fluorescence at various wavelengths of illumination.

Abstract: Automatic printing apparatus wherein a single turnaround item-document is utilized as an initial source of intelligible information-data and thereafter by comparing certain of the data on the document with additional data inputted thereto by means of operably associated external hardware and subsequently summarizing the total data on the item effective to provide a final document including both the initially inputted information-data as well as the data resulting from the comparison and summarization.

Abstract: A typical dust cover for aerosol cans is improved to be more tamper resistant and tamper indicating by adding a specialized tearoff strip. This new combination of dust cover with depending and tight fitting tearoff strip is unitary, has latching lug means as part of both the skirt of the dust cover and the upper edge of the tearoff strip for latching under the valve mounting cups of the can, inhibits the normal camming lever arm, and when the tearoff strip is removed there remains a visually prominent, sinuous bottom edge to the dust cover.

Abstract: A slide motion sampling valve for use with a particle study device and carrying an expansive type microsyringe having a minimum trapped volume. The sampling valve is formed of a slidably movable member carrying a trapping volume, an expansive element and ejection port in the form of a fine aperture, and a stationary element sealingly engaged with said movable member and carrying an opening leading to the entrance of the sheath flow arrangement. The valve operates between a conditon where the ejection port and the opening are aligned and a condition where communication to the entrance is blocked whereby to isolate the trapping volume from said entrance except during ejection of the predetermined amount. One embodiment described employs a linear sliding motion while another embodiment employs a rotating sliding motion.

Abstract: A porosimeter comprises a gas supply, a gas pressure regulator for the gas supply, a sample holder having an inlet and an outlet, said inlet being connected to the gas pressure regulator, a gas pressure sensor connected to the gas pressure regulator for measuring the pressure of gas supplied to the sample holder, and a gas flow sensor wherein the gas flow sensor is disposed to measure the gas flow between said gas pressure regulator and said sample holder. Both pressure and flow-rate readings are taken directly from the respective sensors to an automatic recorder which draws mechanically the output in the form of a graph, or may feed them to, for example, an integrating computer.

Abstract: This invention primarily is directed to a hematology reference control solution, the three separate white cell control portions thereof consisting of three types of fixed red cells of determined size distribution for checking the operation of a particle analyzing instrument, including its predetermined lower and upper threshold settings for each class or subclass of leukocytes.For preparing a human granulocyte analogue, nurse shark erythrocytes are altered and fixed in a chilled solution to simulate in number, size and distribution the granulocytes in human whole blood.