Abstract: Systems and methods resuspend cellular-rich concentrates of blood by rocking the separation chamber to create variable agitation forces within the separation chamber. The systems and methods also add resuspension fluids to aid the resuspension.

Abstract: A method of partitioning a pre-selected phase of a sample of liquid having a plurality of phases of differing densities, a separation device and a tube containing the separation device. The sample of liquid is placed in a first chamber of a linear tube that is separated from a second chamber by a separation device. The separation device slidably engages the interior surface of the tube in an essentially fluid-tight manner and has an axial orifice on the longitudinal axis of the tube that is in fluid flow communication with a flow-restriction channel. The phases are ordered concentrically by rotating the tube around its longitudinal axis e.g. in an axial centrifuge. The volume of the first chamber is reduced by movement of the separation device within the tube, that phase of the liquid located axially within the first chamber flowing into the axial orifice and passing through the flow-restriction channel into the second chamber.

Abstract: The sample separator including a first suction nozzle, serving also as an electrode, for extracting one of first and second components each having an impedance different from each other, a second suction nozzle, serving also as an electrode, for extracting the other component, a nozzle driving member for ascending/descending the nozzles as one unit, and an interface detecting member for detecting an interface between two components. The interface detecting member further including an impedance detector for detecting an impedance between the two nozzles serving also as the electrodes, a storing section for storing a first threshold value to detect the first component, and an operation control member for comparing the first threshold value stored in the storing member with a detected value obtained by the impedance detector, and for controlling the nozzle driving member based on a result of the comparison.

Abstract: Disclosed is an improved method for hemoglobin purification utilizing a novel two-step dual-aqueous-phase extraction technique to separate hemoglobin from red cell membrane stroma and other protein contaminants. In the first step, a first dual-aqueous-phase liquid system is prepared which comprises an upper aqueous phase containing polyethylene glycol in water and a lower aqueous phase containing a phosphate buffer at a pH of about 10. In the second step, a second dual-aqueous-phase liquid system is prepared which comprises an upper aqueous phase, which contains the polyethylene glycol phase containing the hemoglobin extracted in the first step, and a lower aqueous phase containing a new phosphate buffer at a pH of less than 7.5. After the second extraction step, purified hemoglobin solution can then be obtained by removing the phosphate salt and the minute amounts of polyethylene glycol contained in the lower phase.

Abstract: Constituent layers are harvested from a centrifuged multi-constituent material in an evacuated glass or clear plastic tube which contains a float. When possibly contaminated materials, such as blood, are being tested, the use of an evacuated tube allows the measurements to be made without the technician being exposed to the blood. The tubes are large enough to hold approximately one ml of blood, and are filled with an inert gas at low pressure. The floats are formed with a through bore into which cell bands to be harvested will settle during centrifugation. The cell bands are stabilized by a layer of a flowable material which settles onto the plasma layer during centrifugation and forms a pellicle thereon. The cell layers to be harvested are aspirated from the float bore by way of a hypodermic needle or cannula inserted into the tube and float bore.

Abstract: A tube and method of partitioning a pre-selected phase of a sample of liquid having a plurality of phases of differing densities. The tube has a smaller diameter at one end. In use, a sample of liquid is passed through a first end of a linear tube and into a first chamber of said tube. The first chamber is located at the first end of the tube and is separated from a second chamber located at a second opposed end of the tube by a separation device. The separation device slidably engages the interior surface of the tube in an essentially fluid-tight manner and has a flow-restriction orifice therein to permit fluid flow communication between the first and second chambers under the influence of force. The phases are then ordered within the tube using e.g. axial centrifugation. The volume of the first chamber is reduced by movement of the separation device within the tube, such that one phase of the liquid in the first chamber flows through the flow-restriction orifice and into the second chamber.

Abstract: A method of partitioning a pre-selected phase of a sample of liquid having a plurality of phases of differing densities, a separating element and a tube containing the separating element. The sample of liquid is placed in a first chamber of a tube that is separated from a second chamber by a separating element. The separating element slidably engages the interior surface of the tube in a substantially fluid-tight manner. A fluid passage is disposed through the separating element and includes an initially closed fluid passage. The phases are ordered by axial centrifugation wherein the tube is rotated about its longitudinal axis, the separating element is moved within the tube reducing the volume of the first chamber, a pre-selected phase of the liquid is forced from the first chamber through the fluid passage into a second chamber. The reduction of the volume of the first chamber is controlled using phase-separation information. The separator may also include a filter for filtering the fluid.

Abstract: The present invention provides an improvement in separating a mixture of two distinct fluid phases of the same or different materials, one dispersed in the other, by ejecting a flowing stream of the mixed fluid phases from a conduit and then deflecting the ejected stream radially outwardly whereby centrifugal and gravitational forces cause the flowing stream to separate with the less dense phase of the two phases forming a top layer and the more dense phase forming a bottom layer and thereafter directing the more dense phase to flow into a conduit leading to a separate chamber.

Abstract: Apparatus for collecting, containing and separating a sample of blood. Disclosed is an apparatus for separating a pre-selected phase of a sample contained in an enclosed chamber, wherein said apparatus can be used with a separating means which rotates the chamber about a longitudinal axis of the chamber. In addition, separating means in which such an enclosed chamber is rotated about a longitudinal axis is described.

Abstract: A method of partitioning a pre-selected phase of a sample of liquid having a plurality of phases of differing densities, a separation device and a tube containing the separation device. The sample of liquid is placed in a first chamber of a linear tube that is separated from a second chamber by a separation device. The separation device slidably engages the interior surface of the tube in an essentially fluid-tight manner and has an axial orifice on the longitudinal axis of the tube that is in fluid flow communication with a flow-restriction channel. The phases are ordered concentrically by rotating the tube around its longitudinal axis e.g. in an axial centrifuge. The volume of the first chamber is reduced by movement of the separation device within the tube, that phase of the liquid located axially within the first chamber flowing into the axial orifice and passing through the flow-restriction channel into the second chamber.

Abstract: The invention concerns a process and a device for more efficiently obtaining a highly pure fraction of thrombocytes during density centrifugation of blood, which no longer has to be filtered before infusion into a patient for leukocytes contained therein, in order to prevent immunization of the recipient. The invention is based on a two-stage density separation, wherein in a first stage a separation is made between cells and thrombocyte-rich plasma, and the thrombocyte-rich plasma is not separated into a thrombocyte concentrate and thrombocyte-poor plasm until a second stage. During the first separation, the position of the phase boundary is changed cyclically in the first separation stage. Through alternating the phase boundary in the first stage, it becomes possible for the first time in the second stage to obtain highly pure thrombocyte concentrations with minimally low leukocyte contamination from the transferred thrombocyte-rich plasma without loss of efficiency.

Abstract: Nucleated fetal cells such as nucleated fetal red blood cells are separated from maternal blood with a discontinuous triple gradient gel and centrifugation. Nucleated fetal red blood cells are collected at an interface between a gel layer having a density in the range of from 1.105 to 1.110 g/mL and the second layer having a density in the range of from 1.075 to 1.085 g/mL, and maternal granulocytes are collected at an interface between a gel layer having a density in the range of from 1.115 to 1.125 g/mL and a layer having a density in the range of from 1.105 to 1.110 g/mL. This allows separation of fetal cells for testing from the maternal blood rather than the placenta or amniotic fluid, reducing the risk of sample collection and facilitating routine testing of fetal cells for evidence of genetic defects.

Abstract: A method of partitioning a pre-selected phase of a sample of liquid having a plurality of phases of differing densities, and a tube. A sample of liquid is passed through a first end of a linear tube and into a first chamber of said tube. The first chamber is located at the first end of the tube and is separated from a second chamber located at a second opposed end of the tube by a separation device. The separation device slidably engages the interior surface of the tube in an essentially fluid-tight manner and has a flow-restriction orifice therein to permit fluid flow communication between the first and second chambers under the influence of force. The phases are then ordered within the tube using e.g. axial centrifugation. The volume of the first chamber is reduced by movement of the separation device within the tube, such that one phase of the liquid in the first chamber flows through the flow-restriction orifice and into the second chamber.

Abstract: An apparatus for conducting a blotting process comprises a support member, a first electric motor for rotating the support member about a vertical plane, a tube holder having a substantially flat surface for magnetically mounting at least one tube, a second electric motor for rotating the tube holder and a control for controlling the second electric motor. The tube holder is mounted for rotation on the support member. The tube is secured within the tube holder, the support member is rotated at a predetermined angle and the tube holder is rotated at a predetermined speed blotting reagent onto a filter.

Abstract: A method is provided for processing donated blood, particularly a platelet-containing solution such as platelet-containing plasma, involving separating blood into a red cell containing sediment layer and a supernatant layer, and passing the supernatant layer through a filter until the filter is blocked, thereby leaving platelets to be harvested. The preferred filter comprises a porous medium having a plurality of zones of progressively increasing density.

Abstract: Centrifuged material layer measurements are made in an evacuated glass or clear plastic tube which contains a float. When possibly contaminated materials, such as blood, are being tested the use of the evacuated tube allows the measurements to be made without the technician being exposed to the blood. The tubes are large enough to hold approximately one ml of blood, and are filled with an inert gas at low pressure. The floats are formed with a through passage into which the cell bands to be expanded will settle during centrifugation.

Abstract: A serum or plasma collection device including a gel material for partitioning and separating heavier and lighter phases of a fluid sample such as a blood sample. The device preferably includes an affinity member such as a disc-shaped or ring-shaped member or a coating on the collection tube which has an affinity for the separated oil or degradation material from the gel material to prevent the separated material from interfering with the sampling of the separated fluid sample. The affinity member is preferably formed of hydrophobic and/or non-wetted material and has a specific gravity different than the specific gravity of the lighter phase.

Abstract: A radially outward flow turbine having a rotor with nozzles which extend from an inner inlet passage to the rotor periphery with a substantially constant pressure drop per unit length of nozzle, with a first order surface continuity along the surface of each nozzle and with a nozzle profile which allows two-phase flow without substantial lateral acceleration according to the following formula: ##EQU1## The turbine is also illustrated with a second set of nozzles outwardly of the first set included in either the rotor or in a second contrarotating rotor. The rotor in either case vents steam to multiple steam turbine stages while the second set of nozzles receives saturated vapor. The steam turbine stage may be defined by either the first rotor and a stator or the first rotor and a contrarotating rotor.

Abstract: A method for the removal and recovery of paint overspray in a water wash spray booth is disclosed. The method uses a circulating agitated dispersion of an organic solvent component in water which collects the paint overspray. The dispersion containing the overspray is permitted to phase separate into an organic phase and an aqueous phase. The organic phase is further treated such as by distillation to separate the paint solids from an organic solvent portion which contains the original organic solvent component and the organic solvents associated with the paint. The organic solvent portion can be recycled and reused in the circulating dispersion and the paint solids can be recovered for further use such as a filler for adhesives or can be disposed of.

Abstract: A system for collecting and processing donated blood comprises a first porous medium interposed between a blood collection bag and a satellite bag and a second porous medium interposed between the blood collection bag and another satellite bag. The porous media are leucocyte depletion media. The system may also include one or more of the following: a red cell barrier medium, a separation medium, a gas inlet, and a gas outlet. The system can be used to centrifuge whole blood into one or more components, and includes a means for protecting the system during centrifugation.

Abstract: A blood collection tube includes a bottom and an open end that is hermetically sealed by a plug. A supporting film having an anticoagulant coated thereon is positioned within the tube. The anticoagulant-coated surface of the supporting member is provided with a large number of fine convexes.

Abstract: An analytical rotor for separating cellular components from a biological fluid includes a separation chamber spaced radially outward from a sample chamber. The sample chamber may be an open receptacle disposed to receive sample or may be a mixing chamber which receives sample and diluent. A flow restrictive channel connects the sample chamber to the separation chamber so that fluid enters the separation chamber at a controlled rate. The cellular components collect within a retention region located generally at the outer periphery of the collection chamber while cell-free fluid is continuously removed through a collection port. The collection port is spaced annularly apart from the flow channel so that there is sufficient residence time within the separation chamber for substantially complete separation of the cells from the fluid fraction.

Abstract: A modular reaction cassette has a fluid metering mechanism and valves for releasing fluid which are actuated by various centripetal acellerations generated in an automated patient analysis instrument having a variable speed rotor. Various geometries and sealant materials are used to select the rotational speed at which the sealant material yields to operate the metering device and release valves.

Abstract: An apparatus for generating a continuous solution gradient wherein solutions of differing concentrations are layered in a tube and the tube disposed at an angle with respect to the vertical and is rotated for a predetermined period of time thereby to generate a continuous solution gradient, i.e. continuous variation in concentration between the concentration of the initial solutions.

Abstract: A serum separation sealant containing 0.1 to 20 parts by weight of fine resin particles having an average particle size of 0.01 to 2 .mu.m and having an internal crosslinking density of 0.1 to 3 mmol/g and 100 parts by weight of a gelatinous material.

Abstract: The invention discloses a method for treating blood comprising (a) centrifuging blood and (b) passing a supernatant layer of the centrifuged blood through a porous medium until red blood cells block the porous medium.

Abstract: A centrifugal rotor comprising a plurality of peripheral cuvettes and a collection chamber spaced radially inward from the cuvettes is disclosed. The rotor includes a means for introducing fluid into the collection chamber and plurality of generally radial inlet channels connecting each cuvette to the chamber. Each inlet channel has a discrete flow path for fluid to enter the cuvette and another discrete flow path for gas to exit the cuvette as the cuvette is filled. Positioned radially inward from each cuvette is a reflective surface capable of deflecting a light beam from a generally vertical direction to a generally horizontal direction or vice versa. As the rotor is spun, fluid enters the cuvettes from collection chamber through the inlet channels, which also allow gas in the cuvettes to escape, thus avoiding the creation of bubbles in the cuvette after the cuvettes are filled. The contents are then optically analyzed by passing a light beam horizontally through the cuvette.

Abstract: A soil reclamation system that separates the contaminant from all soil particles greater than one micron in diameter and generates resuable soil and contaminant products. The process is based on a novel application of gas-sparged centrifugal separation under operating conditions and equipment specifications tailored to optimize the separation of the particular contaminant. The apparatus is mounted on a front-end loader for mobility and self-contained on site operation.

Abstract: Disclosed is a method for detecting analytes in samples of whole blood using solid-phase, permeable support assay devices. The whole blood assays require no steps or reagents other than those necessary to carry out the same analysis on plasma or serum using the devices. The color visualization of the analytical field on which the interpretation of the assay depends is not affected by the presence of intact erythrocytes or any degree of hemolysis in the blood sample.

Abstract: A liquid separating agent consisting essentially of a copolymer of an .alpha.-olefin having from 6 to 20 carbon atoms and a maleic acid diester with a copolymer composition (molar ratio) such that the maleic acid diester is more than 1.4 mols relative to 1 mol of the .alpha.-olefin, said copolymer having a molecular weight within a range of from 1,000 to 30,000.

Abstract: An assembly for separating, metering and delivering fluids such as whole blood, includes a central rotating member rotatable about a fixed spin axis. A processing chamber holding member is connected to the central rotating member by a centrifugally actuated frame. At rotational speeds below a first predetermined speed, the centrifugally actuated frame is in a first position. At rotational speeds greater than the first speed, centrifugal force moves the frame to a second position angularly spaced from and at greater distance from the spin axis than the first position. A processing chamber is mounted on the holding member and its orientation relative to the spin axis is the same in the first and second positions. Fluid is provided in the processing chamber.

Abstract: Centrifuged material layer measurements are made in an evacuated glass or clear plastic tube which contains a float. When possibly contaminated materials, such as blood, are being tested the use of the evacuated tube allows the measurements to be made without the technician being exposed to the blood. The tubes are large enough to hold approximately one ml of blood, and are filled with an inert gas at low pressure. Dimensional tolerances relative to those of a capillary tube are relaxed for the tube and float due to the larger sample capacity. The cell bands are stabilized by a layer of a flowable material which settles onto the plasma layer during centrifugation and forms a pellicle thereon.

Abstract: An axial flow-type pump for separating immiscible fluids having different specific gravities and a discharge manifold fluid connected to the fluid pump for drawing of the fluid having the heavier specific gravity. The fluid pump employs a rotatable impeller mechanism having a hollow core and a decreasing axial pitch in the direction of fluid flow. The fluid interface between the pump and the discharge manifold is adjustable, so that the discharge of the fluid having the heavier specific gravity can be adjusted. The fluids are introduced into the inlet end of the rotatable impeller to produce a high velocity swirling action in the fluids and a low pressure area along the longitudinal axis of the flow line, to generate a high centrifugal force as the fluids move axially and cause the fluid having the heavier specific gravity to migrate to the perimeter. The discharge manifold is then used to draw off the fluid having a heavier specific gravity.

Abstract: A method for the separation of blood into the components thereof, characterized by subjecting the blood to strong centrifugation thereby separating said blood into an upper layer (A) of platelet-deficient blood plasma an intermediate layer (B) of a mixture of platelets and white blood corpuscles, and a lower layer (C) of a red blood corpuscle concentrate, adjusting the hematocrit value of said red blood corpuscle concentrate of (C) to not more than 80% by diluting said red blood corpuscle concentrate with part of said platelet-deficient blood plasma of (A), and subjecting said mixture of (B) to weak centrifugation thereby separating said mixture into a lower layer of white blood corpuscles and an upper layer of a platelet concentrate, and if desired, subjecting the remaining platelet-deficient blood plasma to the treatments of freezing, thawing, and centrifugation thereby separating said platelet-deficient blood plasma into cryoprecipitate and cryoprecipitate-deficient blood plasma, and apparatus therefor.

Abstract: A centrifugal rotor for separating plasma from whole blood includes a plurality of internal chambers and passages for combining the plasma with one or more reagents and distributing the plasma to a plurality of individual test wells. The chambers and passages necessary for separating the whole blood into plasma are located on a first, upper level within the rotor and include a measuring chamber, an overflow chamber, a separation chamber, and a reagent chamber. The measuring chamber and overflow chamber have capillary dimensions so that an initial volume of whole blood partitions therebetween, with the measuring chamber filling first to provide a preselected volume. The separation chamber is located radially outward from both the measuring chamber and the reagent chamber to that spinning of the rotor causes both the reagent and the measured blood volume to flow outward into the separation chamber.

Abstract: Method and apparatus for separating water and crude oil mixtures and other two-phase fluid mixtures of components of different densities. The mixture is pumped through a conduit in the form of a vertical spiral at a velocity that impels the heavy phase toward the outside of the spiral. A fraction is withdrawn from the outside of the turns of the spiral and is led downwardly to the bottom of a vertical settling tank. Any light phase removed with the heavy phase floats to the top in the settling tank and is reintroduced at the top of the spiral.

Abstract: A composition is provided for use, particularly in evacuated blood collection tubes, as a blood partitioning composition. The composition is useful in provididng cleaner serum or plasma samples for biochemical tests, including a wide range of drugs. The composition includes a balanced dual resin component which provides the desired hydrophobic property while simultaneously controlling viscosity and the specific gravity, which component is comprised of poly-alpha-pinene resin which provides good drug recovery but low density with a chlorinated hydrocarbon resin which provides the proper density level while maintaining the desired hydrophobic property of the resin blend. Thixotropic property is achieved by adding silica and network stabilizer in the composition.

Abstract: Apparatus and a method are described, wherein a coagulator accelerator is added to a container to achieve agglutination of blood cells when centrifuging whole blood, allowing the serum to be more easily poured off. The accelerator is selected from polymeric amines that are either polymerized amino acids or vinyl addition polymer amines, with a specified molecular weight range, the vinyl addition amines being selected to avoid lysing the blood cells.

Abstract: A method for separating blood into blood components aseptically in a closed system first filters whole blood through a filter for removing leukocytes or removing leukocytes and platelets, to produce filtered blood, which is passed to and collected in a primary bag fluid-tightly connected to the filter through a sealable, cuttable conduit, and the conduit is sealed and cut to disconnect the primary bag from the filter. The disconnected primary bag is subjected to centrifugation to separate the filtered blood into blood components. The method is useful for separately collecting leukocyte-removed blood components, particularly leukocyte-removed erythrocytes, leukocyte-removed plasma, leukocyte-removed platelets, etc., from the whole blood of a healthy human. A blood components separation unit which can advantageously be used in the practice of the above method is also disclosed.

Abstract: An assembly for separating lymphocytes and monocytes from granulocytes in a sample of unseparated whole blood. A water insoluble, thixotropic gel-like substance, which is chemically inert to blood constituents is provided in a container. A fluid capable of altering blood cell densities and diameters is positioned above the surface of the water-insoluble thixotropic gel-like substance. Means for preventing the absorption of water by the thixotropic gel-like substance from the fluid and/or the sample of unseparated whole blood prior to separation are provided to substantially eliminate the influence of water absorption on the cell separation performance characteristics of said thixotropic gel-like substance.

Abstract: A device for separating mononuclear cells from blood includes a collection tube, a first layer of a liquid density gradient material placed in the tube, a second layer of a gel-like substance placed in the tube and situated above the first layer, a porous foam member placed in the tube and situated above and in contact with the second layer of gel-like substance, and a third layer of a Newtonian gel-like substance placed in the tube above the porous foam member. The gel-like substance of the second layer has a lower specific gravity than that of the liquid density gradient material of the first layer so that it floats on top of the first layer. The gel-like substance of the second layer becomes less viscous when heated such that it is absorbed by the porous foam member and forms a hydraulic barrier between the liquid density gradient material of the first layer and a blood sample placed in the collection tube.

Abstract: In a blood serum separator tube for separating blood into a lighter phase and a heavier phase, the thixotropic gel material initially disposed in the container lower end of the tube is protected from contact with any atmosphere contained in the tube, thus preventing separation of silicone oil from the silica-silicone fluid gel material during manufacture or storage. The gel material may be microencapsulated, or contained in a smaller number of larger capsules, or a single capsule. Alternatively, the gel material may be sealed in the tube under a curable elastomeric material, or under a water soluble material which dissolves upon contact with the blood being separated.

Abstract: An apparatus for processing and analyzing blood serum includes an input rack for holding test tubes containing whole blood specimens and separator gel, a centrifuge, an optical sensing unit for receiving centrifuged test tubes and generating output signals indicative of whether the centrifuging was successful and, if it was, the boundary position between the separator gel and the blood serum, and a computer connected to receive and analyze the output signals of the optical sensing unit. An aspirator/dispenser needle unit is positioned above the sensing unit and is capable of lowering a needle, under the control of the computer, to puncture the stopper of a test tube and then withdraw blood serum.

Abstract: A set for the isolation of cryoprecipitate includes a hollow vessel with a closed first end, a second end and a longitudinal axis, and a nipple extending from and closing the second end, said nipple enclosing a volume of approximately 2 to 5 percent of the volume of the hollow vessel. In one embodiment, the vessel is formed of a semi-rigid material and the first end is closed by a cap containing a micro-porous filter for venting the vessel. In another or further embodiment, the nipple has a tapered tip portion which may be sliced off to permit extrusion of the isolated cryoprecipitate by squeezing the vessel. In a different further embodiment, the nipple has a twist-lockable connector, for attachment to a syringe or to an applicator tip. In yet another embodiment a piston mounts on the cap within the vessel for directly extruding separated cryoprecipitate from the nipple.

Abstract: A set for the isolation of cryoprecipitate includes a hollow vessel with first and second ends and a tapered body extending to a narrow sump closing the second end, said sump enclosing a volume of approximately 2 to 5 percent of the volume of the hollow vessel. A port enters the vessel in the tapered body above the sump. In one embodiment, the vessel is formed of a rigid or semi-rigid material and the first end is closed by a cap containing a micro-porous filter for venting the vessel. In another or further embodiment, the sump has a tapered tip portion which may be sliced off to permit extrusion of the isolated cryoprecipitate by squeezing the vessel. In a different embodiment, the vessel contains an inner filter column, or bag with a filter matrix, accessible via an access port. Cellular material placed in the column is frozen, thawed and centrifuged to separate out antigen-free platelet growth factor with the cryoprecipitate.

Abstract: An automatic apparatus for the selective extraction of phases from a multiphase system in a receptacle distinguished by their opacity difference comprising a stirrup (1) moveable with respect to the receptacle (2) containing the multiphase system of different opacity (3) and (4), a control means (5) for moving the stirrup (1) which is sensitive to the change of opacity of the phases present in the receptacle (2) and a means (6) for effecting the extraction of the phase secured to the stirrup (1) which is especially suitable for extraction of biological fluids, particularly blood.

Abstract: A blood separation device includes a collection tube containing a first layer of a thixotropic gel-like substance and a second layer of a newtonian gel-like substance which is positioned below the first layer. The first layer of the thixotropic substance is positioned between the second layer of the newtonian substance and a blood sample received by the tube, prior to centrifuging the tube, and acts as a barrier between the second layer and the blood sample to prevent intermixing of the second layer and the blood sample. The thixotropic gel-like substance of the first layer has a specific gravity which is greater than the newtonian gel-like substance of the second layer whereupon centrifugation of the tube, the first layer moves to a position below the second layer.

Abstract: An assembly for separating lymphocytes and monocytes from granulocytes in a sample of unseparated whole blood. A water insoluble, thixotropic gel-like substance, which is chemically inert to blood constituents is provided in a container. A fluid capable of altering blood cell densities and diameters is positioned above the surface of the water-insoluble thixotropic gel-like substance. Means for preventing the absorption of water by the thixotropic gel-like substance from the fluid and/or the sample of unseparated whole blood prior to separation are provided to substantially eliminate the influence of water absorption on the cell separation performance characteristics of said thixotropic gel-like substance.

Abstract: A system and method of separation of therapeutic components from blood. The system includes a dual member centrifuge and a disposable single use fluid transfer set. The set includes an elongated flexible separation chamber having an input port, a separated component output port and a residual fluid output port. The input port and the separated component output ports are located at opposite ends of the elongated separation chamber. The centrifuge includes a receiving chamber with a selectively formed annular slot therein. The separation chamber is positioned in the annularly shaped slot and rotated at a predetermined rotational velocity. Fluids such as whole blood flows through the separation chamber and are separated into various therapeutic components such as platelet rich plasma and residual concentrated red blood cells. Platelet rich plasma can be drawn off as the separated therapeutic component. An alternate two part transfer set provides for highly efficient platelet pheresis.

Abstract: A process for high speed separation of ultra-high molecular weight polymers using a hyperlayer field-flow fractionation technique comprising forcing a carrier fluid containing a small sample of the high molecular weight polymer through a thin flow channel possessing an accumulation wall, applying a primary externally controlled driving force transversely across the thin dimension of the channel, adjusting the flowrate of the fluid and the field strength of the primary externally controlled force in relationship to the channel thickness such that at least over part of the molecular weight range the entropic force F.sub.e and the primary driving force F.sub.1 are related by the inequality .vertline.F.sub.e .vertline.>.vertline.F.sub.1 .vertline. at the accumulation wall of the channel.