Abstract: An electromagnetic immune tissue invasive system includes a primary device housing. The primary device housing having a control circuit therein. A shielding is formed around the primary device housing to shield the primary device housing and any circuits therein from electromagnetic interference. A lead system transmits and receives signals between the primary device housing. The lead system is either a fiber optic system or an electrically shielded electrical lead system.

Abstract: A method of detecting an optical change in a series of test assays producing detectable results at varying efficiencies, the method comprising the steps of: a) selecting a test assay from the series, the selected assay having a known end-point photoresponse efficiency and a known filter center wavelength; b) providing a variable-intensity flash lamp illuminator comprising a lamp, a set of multiple filters with pre-selected center wavelengths assigned to particular assays, and a circuit for activating the lamp and comprising a capacitor, a power source, and a variable output voltage converter connected to the source and having its variable voltage output connected across the capacitor, the lamp and the filters providing a known level of system efficiency as a function of the center wavelength of the filter; c) providing a predetermined relationship of levels of illuminating intensities from the lamp as a function of photoresponse efficiencies of the assays and the system efficiencies, in which the photorespons

Abstract: There is disclosed a reflectometer which uses an integrating cavity interposed between a pulsed light source and a test element. The cavity has enhanced efficiency by reason of its construction wherein a diffusely-reflecting surface is connected at opposite edges to mirrored surfaces that reflect back to the diffusely-reflecting surface, at least the majority of diffusely-reflected rays that are non-aligned with selected rays from the diffusely-reflecting surface that impinge unimpeded on the test element.

Abstract: There is disclosed a pipette useful with disposable tips, comprising a plurality of differently-sized pistons and a piston chamber for each piston. Each piston chamber has a vent passageway extending to the exterior surface of the pipette. The pipette is improved in that the mounting means for mounting a disposable tip comprises, not one surface, but a plurality of differently-sized surfaces. Furthermore, the vent passageway for all but the smallest piston chamber exits at a location in between the mounting surface for the tip of that particular piston chamber and the next smaller mounting surface, whereby the larger disposable tips seal over the vent passageways of the smaller disposable tips.