Abstract: Methods for stray light measurement and compensation in spectrophotometers are disclosed. In one exemplary embodiment, stray light is determined as a convolution of a selected detected radiant power spectrum and a monochromator slit function. Such a stray light measurement may be made with or without the sample in an optical path between a source and detector within the spectrophotometer. When made with the sample in the optical path, the resulting stray light measurement may be used to compensate sample absorbance or transmittance measurements. In accordance with another embodiment of the present invention, sample absorbance or transmittance may be compensated in a method including measuring sample detected radiant power at a wavelength outside an interval of significant detected radiant power within which a sample measurement compensated for stray is desired.

Abstract: A thick walled centrifuge tube with a generally constant internal diameter and having at least one circumferential groove within the exterior surface of the tube. The groove is designed to have a depth slightly less than the wall thickness of the tube. The circumferential groove is designed to assist in slicing of the tube subsequent to centrifugation in order to isolate different separated particles of a fluid sample which have formed fraction bands at certain levels in the tube. The groove reduces the cutting force required to partition the tube. The groove provides a guide for a slicing blade. The groove is formed in such a manner that a fluid tight seal is formed between the slicing blade and the tube as the blade proceeds through the tube. The centrifuge tube wall at the base of the groove, after slicing, is resilient enough to allow the tube sections to be rejoined under force and create a fluid tight seal.

Abstract: A method, kit and a solution for assaying enzyme, such as prostate acid phosphatase (PAP), in a sample. The sample is contacted with a first antibody (Ab.sub.1) against the enzyme and incubated. The resulting Ab.sub.1 -enzyme complex is contacted with a second antibody (Ab.sub.2) specific for Ab.sub.1. The resulting Ab.sub.2 -Ab.sub.1 -enzyme complex precipitates out of the medium. The precipitated complex is separated and solubilized with a pH controlled solution of gamma globulin. The resulting solution is then assayed for enzyme activity.

Abstract: Sample handling apparatus for circulating one or more sample holders along a rectilinear path in a sample holder storage compartment and past an operating station at which the holders may be removed from and then returned to the compartment. First and second parallel conveyors on opposite sides of the operating station drive the holders toward and away from the operating station. Lateral drivers engage the holders in longitudinal stop positions at opposite ends of the conveyors and drive them laterally between conveyors to lateral stop positions, one of the holders during lateral movement being driven into and away from an operative position at the operating station. A movable sample compartment divider between the conveyors is indexed in synchronism with the lateral drivers to engage and stabilize the sample holder at the operating station.

Abstract: Sample handling apparatus for circulating one or more sample holders along a rectilinear path in a sample holder storage compartment and past an operating station at which the holders may be removed from and then returned to the compartment. First and second parallel conveyors on opposite sides of the operating station drive the holders toward and away from the operating station. Lateral drivers engage the holders in longitudinal stop positions at opposite ends of the conveyors and drive them laterally between conveyors to lateral stop positions, one of the holders during lateral movement being driven into and away from an operative position at the operating station. A movable sample compartment divider between the conveyors is indexed in synchronism with the lateral drivers to engage and stabilize the sample holder at the operating station.

Abstract: A hanger for supporting one side of a swinging bucket in a centrifuge rotor. The hanger is adapted for use in pairs, mounted one on each side of a space in a rotor, for containing a swinging bucket. The hanger is provided with an opening for receiving the pivot pins of the bucket and supporting it thereby. Ramp means are disposed on the upper side of the hanger for guiding the pivot pin of the bucket into the opening in the hanger, thereby enabling the pivot pin to be self-seating in the hanger through the effect of gravity when the bucket is deposited in the rotor. The hanger includes spring means for enabling the pivot axis of the bucket to move radially outward in response to centrifugal force and enable the bucket to engage a portion of the rotor.

Abstract: In an optical instrument including a birefringent liquid crystal cell of the type consisting of a pair of transparent plates and a zero-twist, nematic-phase, liquid crystal material with a positive dielectric anisotropy between the plates, the liquid crystal molecules being oriented in and tilting in a plane perpendicular to the cell plates, a beam of light being conducted through the cell, generally normal to the plates thereof, it has been observed that if all of the rays of the beam are not collimated, each ray will suffer a different retardation in passing through the cell and this is unacceptable in most applications. This problem is minimized, according to the present invention, by using a filament light source positioned with the filament axis normal to the plane of the tilting molecule axes or by using two liquid crystal cells between a pair of polarizers, one of the cells being rotated 180.degree.

Abstract: A method for measuring the concentration of a gas. The method includes circulating an electrolyte solution between an electrode and a gas-permeable, ion-impermeable membrane spaced from said electrode. The ionic concentration is measured after the circulating electrolyte has been stopped.

Abstract: A rotor adapted for containing a plurality of sample tubes and for retaining the contents of such tubes if any should rupture while in the rotor. The rotor includes an upper shell and a lower shell connected by a central hub interposed therebetween. Provision is made for coupling the hub to a drive shaft. The upper shell has a substantially frustoconical shape and a recessed top surface. The top surface has a form generally corresponding to the interior of an inverted frustum. A plurality of sample tubes are disposed in a circular locus in the top of the rotor. The lower shell of the rotor has a bottom formed with upturned inwardly sloping conical sides. The sides are disposed such that their uppermost portion is proximate the upper shell. In the event that one or more tubes ruptures while in the rotor, the contents will be retained in the lower shell rather than spilling into the rotor chamber.

Abstract: A column for use in DNA synthesis. The column is transparent and is disposable to allow access to the resin beads within the column. The column includes end caps which are engageable with a housing and a screw to secure the column in the housing.

Abstract: An ultracentrifuge rotor comprising a body portion formed as a bowl with a central open chamber defined by a thin, cylindrical wall extending from a supporting base and a plurality of nested rings of filament windings surrounding the cylindrical wall for strengthening and stiffening same. The nested rings result in a uniform filament density throughout the ring assembly.

Abstract: A double beam photometric flow cell for high pressure liquid chromatography having illuminated sample and reference passageways therein, the sample passageway receiving flowing fluid sample fractions for analysis. Regulating apertures control the relative amount of light passed through the passageways such that the light energy through the reference passageway exceeds that through the sample passageway. This reduces the contribution of the reference path to "shot noise" in the photometer output signal.