Abstract: Fluid sample purification systems and methods are provided for isolating molecules of interest in a fluid sample. The fluid sample purification system has a housing with a distal end and distal opening adapted for the passage of a fluid and a proximal end and proximal opening adapted for passage of a fluid. A distal retainer is located inside the housing and above the distal opening. A proximal retainer is located inside the housing between the distal retainer and the proximal opening, or is located adjacent to, in contact with, or over the proximal opening. The system also comprises adsorption material, e.g., functionalized particles, inside the housing and confined between the distal retainer and the proximal retainer. The adsorption material adsorbs undesirable material while simultaneously rejecting desirable materials. Methods are also provided for isolating molecules of interest using the fluid sample purification system.

Abstract: A perfusion chamber includes a porous oocyte support structure. A continuously sloped top surface and a receiving well in the support structure entrap the underside of the oocyte, thereby localizing the cell in a predetermined fixed position within the reach of dedicated voltage-clamp microelectrodes. A test solution is delivered continuously at the top of the chamber, above the oocyte, and withdrawn from the bottom of the chamber, below the oocyte. The porosity of the support material enables the continuous perfusion of test solution around the membrane of the oocyte, including its bottom portion that is held firmly in contact with the holding well. The geometry of the holding well is selected such as to ensure the automatic and precise placement of the oocyte by gravity and to optimize the pressure distribution over its membrane, thereby minimizing the probability of rupture or other damage to the cell.

Abstract: The present invention provides a novel dry analytical element for determination of an analyte in a fluid sample in thin film immunoassay, particularly chemiluminescence, fluorescence and colorimetry immunoassay. There is provided an analytical element comprising a support member, a reagent matrix comprised of at least one layer of a porous material carried on the support member, the matrix including a read area, an absorbent material in contact with the matrix, and light absorbing or reflecting means integral to the absorbent material and/or positioned between the absorbant material and the read area for absorbing or blocking background signal generated by washed, removed label and other interferents from outside the read area prior to it moving back into the read area. The analytical element can comprises a cover depending on the type of immunoassay to be conducted.

Abstract: A stack of plastic articles and a process of forming the stack are disclosed. Preferably the stack is of heat-fusible plastic slide elements for use in a diagnostic analyzer, the elements being temporarily and non-destructively fused together so that the stack can be used free of a cartridge.In another embodiment, the stack can be of any plastic article temporarily fused to adjacent elements, one side edge of each element bearing a colorant and another bearing no colorant, so that a bar code for the stack is inherently formed simply by rotating each element to project outwardly the colored side edge or the side edge lacking colorant, prior to fusing the elements together.

Abstract: A stack of plastic articles and a process of forming the stack are disclosed. Preferably the stack is of heat-fusible plastic slide elements for use in a diagnostic analyzer, the elements being temporarily and non-destructively fused together so that the stack can be used free of a cartridge. In another embodiment, the stack can be of any plastic article temporarily fused to adjacent elements, one side edge of each element bearing a colorant and another bearing no colorant, so that a bar code for the stack is inherently formed simply by rotating each element to project outwardly the colored side edge or the side edge lacking colorant, prior to fusing the elements together.

Abstract: A novel slide test element and method of making are described. Both feature a lip coined in the sidewall of a recess shaped in a frame member to hold the reaction member bearing the detecting reagents. The lip then overhangs the reaction member, once assembled. Assembly occurs by bending the frame member with the lip facing outwardly, thus forcing the lip to part a distance sufficient to allow the reaction member to be inserted. An optional stacking and fusing procedure is also described to facilitate shipment of frame members prior to assembly.

Abstract: There are disclosed an ISE slide element and potentiometric measurement of assaying, using a slide element that is positionally insensitive about an axis of symmetry. This is achieved by accessing one of the electrodes in the center of the slide element, and the other in an annular groove centered on the element center, both for liquid contact and electrometer contact. Preferably, electrometer contact occurs at a side of the electrode opposite to the side contacted with liquid.

Abstract: There is disclosed a method of laser-marking plastic articles without unduly damaging the plastic. The method comprises coating the plastic with a contrasting color layer, and intermediate the color layer and the plastic, a protective layer of a dried coverage of at least 1.5 g/m.sup.2.Optionally, the ablation can be carried out beyond the stripe portion to be marked, to clear away any debris from the white support that otherwise can be left behind by the ablation.

Abstract: To cinch a web end portion onto a core, the core is center driven by a core driving mechanism at an outer peripheral speed in excess of the speed at which the web end portion is fed to and threaded around the core. After the web end portion is cinched onto the core and the web wound to form a roll of predetermined diameter, the core drive mechanism is disengaged from the core to terminate the core center drive. The outer surface of the roll further substantially simultaneously engages a roll surface drive mechanism which is normally spaced from the core for surface driving the roll.