Abstract: A method and device are provided for separating a sample, such as a protein, into its components by two-dimensional electrophoresis wherein instead of bringing the first separation medium, e.g., a fragile elongated gel strip, into contact with a second separation medium, e.g., a gel slab, after the former has been subjected to electrophoresis, the second separation medium is formed or cast in place along the length of the first separation medium only after the latter has undergone electrophoresis separation.

Abstract: An electrophoresis cassette is provided including a thin, flat, rectangular, molded plastic front plate which overlies a thin, flat, rectangular, molded plastic back plate in opposing spaced apart relationship, the front and back plates being separated from each other by a thin, narrow, generally U-shaped embossment formed on the opposing surface of the back plate and extending along the two opposite side edges and the bottom edge of the back plate. A liquid-tight seal formed by an ultrasonic weld extends continuously along the embossment and joins the plates together, the plates defining therebetween a narrow gap for holding a gel medium. An elongated narrow groove is provided within the non-opposing surface of each plate and extends in substantially coinciding relation with the groove in the other plate across the bottom of the plates at a point just above the seal, the grooves forming at the bottom portion of the cassette a tab which can be easily broken off to expose the gel medium within the gap.

Abstract: An electrophoresis device comprising a pair of electrically-insulating, liquid impermeable sheets disposed in spaced apart relationship to one another and a gel membrane disposed between the sheets acting as an electrophoresis medium, the gel membrane having a substantially flat surface thereon disposed below an edge of the sheets defining together with the sheets an elongated slot of predetermined thickness, wherein at least one liquid impermeable, elastomeric, compliant member, such as a solid cylinder or tube, is disposed within the slot and forms at least one sample well above the gel membrane.

Abstract: By providing two, interconnected fluid storing containers, each of which comprise piston members sealingly engaged therewith and manually movable along the inside surface thereof, a unique, linear gradient former is achieved which is capable of controllably providing precisely mixed linear gradients. In addition, the linear gradient former of the present invention is usable to quickly, easily, and precisely fill the fluid holding chambers, by manually moving the pistons in an opposite direction. One of the fluid storing containers incorporates outlet means for delivering the linear gradient to the desired chamber for use and, in the preferred embodiment, also incorporates fluid mixing means to assure uniform distribution of the fluids in the container prior to being dispensed.

Abstract: The invention is directed to a dual-piston reciprocating pump assembly which includes two opposed substantially identical reciprocating pumps, a housing within which the pumps are mounted, a cam mounted on a cam shaft which is driven through a coupling by a stepping motor, each of the pumps including a piston assembly comprising a piston body having a piston end, the other end of the piston body being in the form of a yoke which is mounted for reciprocating motion in the housing, a cam follower carried between the arms of the yoke for engaging the cam face of the cam, a cylinder head having a piston cylinder therein for receiving the piston end, the housing having an end opening for receiving said cylinder head, a guide bushing mounted in the cylinder head for facilitating the assembly of the piston end, an inner bearing bore for the piston end disposed adjacent the guide bushing, a high-pressure seal disposed adjacent the inner bearing bore, the piston end having substantial radial end play, and a piston spr

Abstract: The invention is directed to a dual-piston reciprocating pump assembly which includes two opposed substantially identical reciprocating pumps, a housing within which the pumps are mounted, a cam mounted on a cam shaft which is driven through a coupling by a stepping motor, each of the pumps including a piston assembly comprising a piston body having a piston end, the other end of the piston body being in the form of a yoke which is mounted for reciprocating motion in the housing, a cam follower carried between the arms of the yoke for engaging the cam face of the cam, a cylinder head having a piston cylinder therein for receiving the piston end, the housing having an end opening for receiving said cylinder head, a guide bushing mounted in the cylinder head for facilitating the assembly of the piston end, an inner bearing bore for the piston end disposed adjacaent the guide bushing, a high-pressure seal disposed adjacent the inner bearing bore, the piston end having substantial radial end play, and a piston sp

Abstract: The invention is directed to a dual-piston reciprocating pump assembly which includes two opposed substantially identical reciprocating pumps, a housing within which the pumps are mounted, a cam mounted on a cam shaft which is driven through a coupling by a stepping motor, each of the pumps including a piston assembly comprising a piston body having a piston end, the other end of the piston body being in the form of a yoke which is mounted for reciprocating motion in the housing, a cam follower carried between the arms of the yoke for engaging the cam face of the cam, a cylinder head having a piston cylinder therein for receiving the piston end, the housing having an end opening for receiving said cylinder head, a guide bushing mounted in the cylinder head for facilitating the assembly of the piston end, an inner bearing bore for the piston end disposed adjacent the guide bushing, a high-pressure seal disposed adjacent the inner bearing bore, the piston end having substantial radial end play, and a piston spr