Abstract: Horizontal electrophoresis is performed in a cell that includes a tank and a pair of electrodes, each mounted on an electrode support that is easily inserted into and removed from the tank, and once inserted, is secured in position by one or more spring-loaded, manual-release locking features.

Abstract: Membrane-encased structures such as biological cells, liposomes, and vesicles, are conveyed through one or more channels in a rotating disk for individual exposure to optical elements or to electrodes, for purposes of transfection or flow cytometry. The rotation of the disk serves either to provide centrifugal force to urge the cells against one wall of the channel and in certain embodiments to move the cells through the channels, or to draw cells at preselected times or intervals into the exposure zone, or all three.

Abstract: A multi-well plate with wells having ultra-thin walls and yet with sufficient structural rigidity to allow reliable use of the plate in automated instrumentation is formed by first forming a plate blank by injection molding, the blank being of a thickness that provides the desired rigidity, and then subjecting the blank to vacuum forming to stretch designated areas in the blank to form wells or to extend wells already formed, the stretching resulting in a reduction in thickness of the molded resin at the walls of the wells only.

Abstract: A thermal cycling instrument for PCR and other reactions performed on multiple samples with temperature changes between sequential stages in the reaction procedure is supplied with a thermal block to provide rapid changes and close control over the temperature in each sample vessel and a pressure plate incorporated into a motorized lid that detects anomalies in the reaction vessels or in their positioning over the thermal block, and automatically adjusts the plate position to achieve an even force distribution over the sample vessels.

Abstract: Adherent cells on the surface of a disk are transfected by electroporation between coaxial circular cylinders with electrodes on the opposing surfaces on either side of the annular space between the cylinders by placing a buffer solution containing the transfecting species in the annular space over the cell and applying an electric potential between the electrodes.

Abstract: An electroporation cuvette is constructed with electroporation electrodes arranged in non-parallel relation to form a gap whose width varies with the location within the cuvette, plus a pair of positioning electrodes that are arranged to cause electrophoretic migration of biological cells within the cuvette according to cell size. Once the cells, suspended in a solution of the impregnant, are distributed in the cuvette by the positioning electrodes, electric field pulses are generated by the non-parallel electroporation electrodes. Because of their distribution in the cuvette, the various cells will experience voltage differentials across their widths that approach uniformity regardless of cell diameter, since the larger cells will be positioned at locations where the gap between the electrodes is greater and the smaller cells at locations where the gap is relatively small while the voltage drop across the entire gap is uniform along the length of the cell.

Abstract: In an affinity-type purification, ligands dissociated from the stationary phase that would otherwise leach into the species being purified are captured by a second ligand that is also incorporated into the stationary phase, the second ligand exhibiting an affinity-type interaction with the dissociated first ligand with sufficient specificity to avoid the undesired retention by the second ligand of species from the liquid sample or source liquid other than the species sought to be purified in the affinity column.

Abstract: Purification of either DNA or RNA and amplification through PCR or reverse-transcriptase PCR are performed in a common microfluidics device by the inclusion of diatomaceous earth in a reservoir within the device and by the use of microfluidics technology for conveying fluids through the reservoir and through microchannels within the device.

Abstract: A slab gel electrophoresis cassette with an integrated upper buffer chamber is constructed such that the integrated chamber is collapsible to allow the cassette to assume a reduced thickness for purposes of stacking during storage and shipping.

Abstract: A platform that supports a sample plate such as a microtiter plate, a multi-well plate of any size, or a glass slide with sample spots distributed over its surface, and presents the plate for assay detection by a movable scanning head that has a field depth on the millimeter scale is leveled or otherwise adjusted in a planar orientation by an apparatus that includes a rocker plate, position sensors, and motorized risers arranged on the apparatus to provide the rocker plate with tilting capability along either or both or two orthogonal axes.

Abstract: A moving coil actuator that moves in a rapid back-and-forth motion is constructed with a magnet assembly that concentrates the magnetic flux in a region of limited length and with a coiled electric conductor that includes two separated regions of densely wound coil, the assembly and conductor arranged such that only one of the coil regions resides in a concentrated flux region at either end of the actuator stroke. This is achieved with either a single region of concentrated flux or two spatially separated regions of concentrated flux. In either case, the force constant, i.e., the motor force generated in each coil per unit of current through the coil, is non-linear, with a maximal force at each end of the stroke and a minimal force at the stroke mid-point. The result is an efficient use of the electric current and relatively small amounts of materials of construction, and accordingly less weight for the actuator to carry during its travel and its changes of direction.

Abstract: Biochemical assays of samples in receptacles, in gels, in blots, in arrays and the like, and that utilize excitation and light emission as labels for detection are enhanced by an illumination and detection system that supplies excitation light through an optical fiber that transmits excitation light from an excitation light source to the sample. Emission light produced by the excitation is then collected by a lens and converted to a signal that is compiled by conventional software for analysis. The optical fiber transfixes (passes through) the lens via a slot or other opening and is preferably offset from the center of the lens. The optical fiber and collecting lens can either be on the same side of the sample or on opposite sides, i.e., one above and the other below.

Abstract: Erythrocytes from a vertebrate animal other than a human that have been size reduced and treated with a fixing agent by conventional methods to resemble human platelets are further treated to achieve a size distribution that is detected in a consistent manner by different methodologies of blood cell counting. The further treatment includes heating to a denaturing temperature followed by a second treatment with a fixing agent. The resulting cells are useful as controls for calibrating and checking the accuracy of automated blood cell counting equipment.

Abstract: A chromatography cartridge with a packed bed is manufactured from an inner and outer chamber, the inner chamber being in an insert that is slidable into the outer chamber with openings in each such that a slurry that is originally placed in the interior of the outer chamber flows into the inner chamber as the parts are being pressed into each other. During the assembly, the particles in the slurry are compressed to fill the smaller volume of the inner chamber and excess liquid is discharged through ports in both chambers. The construction allows for a highly precise and reproducible column filling process with a minimum of steps and operator intervention and thereby low cost and reduced error.

Abstract: A priming unit for a microfluidics device contains a pressurization unit and pressure and temperature detectors as part of a feedback loop that controls the pressure applied by the pressurization unit and the time during which the pressure is applied. This control feature is particularly useful in controlling the exposure time of the microchannels to dyes in the priming liquids since certain dyes tend to adhere to the walls of the channels and produce non-uniform results.

Abstract: Light-emitting diodes are mounted in a support block that holds the diodes in a fixed orientation. In certain embodiments, the orientation of the diodes by the support block causes the axes of the diodes to converge below the block to a common point where, in preferred embodiments, components of an excitation optical system are placed. The converging light then diverges for entry into an array of receptacles in which individual chemical reactions take place. The block contains engineered apertures that securely retain the diodes, each aperture including a shoulder for the flange at one end of each diode.

Abstract: Carboxylic acid-substituted polyalkylene polyamines in which amine nitrogen atoms on the polyamine backbone structure are replaced by guanidine groups provide a pH range extending into high pH values. These substances are useful as carrier ampholytes in isoelectric focusing.

Abstract: Analyses of serum samples for the presence and amount of either of the two subunits of human Factor XIII protein are used as a means of eliminating a significant source of error that arises in the testing of serum and plasma. For serum samples, a negative result of an analysis for the presence of subunit a is a means of verifying that a sample is indeed serum, while a negative or positive result for subunit a serves to distinguish serum (negative) from plasma (positive). A positive result for the presence of subunit b is a means of verifying that the sample is either serum or plasma and not any other biological fluid. A quantitative analysis of subunit b is a means of verifying that the sample is of the intended volume rather than having been reduced in volume due to improper sampling. A quantitative analysis of subunit b is also a means of verifying the dilution of a sample of either serum or plasma.

Abstract: Gel plugs that can be stored in a sealed condition and delivered individually to an electrophoresis gel as standards for electrophoretic separations are retained in a cartridge that is cleanly breakable into individual sections, each section retaining a gel plug of predefined dimensions with standard solute mixtures embedded in the plug. The separation of any single section from the cartridge exposes opposing edges of the gel plug which permits the user to insert an implement into the section interior and to urge the plug out of the section and into a well of an electrophoresis gel. All manipulations are performed without any need for contact between the user and the gel.

Abstract: Irregularities in the pore structures of polyacrylamide gels that are formed in cassettes against plastic walls are reduced or eliminated by the inclusion of an oxygen scavenger in the gel-forming solution. Avoidance of the irregularities results in electropherograms with fewer distortions in the solute bands.