Abstract: A gas mixture having a preselected concentration of nitric oxide, usable in inhalation therapy for example, is produced by controllably establishing the coulometric reduction of copper ions in a solution of nitric acid accompanied by purging the chamber in which the reduction reaction occurs with an inert gas. A free-standing, portable NO generator for use in the production of such a gas mixture is also disclosed.

Abstract: A chromatically variable light source includes a plurality of light emitting diodes which generate substantially monochromatic light at different wavelengths. The light source includes circuitry for selectively energizing one or more of the light emitting diodes and for controlling the intensity of the generated light. The light generated by the light emitting diodes is combined in a single light pipe and delivered to an output port for use.

Abstract: The chemical properties of an aqueous liquid, the liquid comprising a solvent having an index of refraction which is the same as or closely approaches that of water, are determined by Raman spectroscopy wherein a sample of the liquid is delivered into an optical waveguide. The waveguide is in the form of a capillary having a reflective surface defined by a material having a refractive index of less than 1.33. Excitation light is transmitted axially into the liquid at an end of the waveguide. The excitation light is transmitted the length of the waveguide, by reflection from the reflective surface, causing the fluid to emit Raman spectra. The Raman spectra is transmitted along the waveguide, collected and delivered to a spectrometer.

Abstract: Water or some other aqueous fluid is employed as the light transmitting medium of a liquid core fiber-optic waveguide cell by employing, to define the core region, a waveguide vessel having an exterior coating composed of a material having a refractive index of less than 1.33. The light conducting channel defined by the aqueous fluid filled core may be a capillary or other suitably shaped vessel.

Abstract: A device for delivering precisely measured, minute quantities of liquid has no metal parts which contact the liquid. The device employs a barrel defining member with a bore which receives a polymer coated glass or ceramic fiber which functions as a piston. Fluid is drawn into and discharged from the bore via a needle in the form of a polymer coated glass or ceramic capillary tube.

Abstract: The chemical properties of a flowing liquid analyte, the analyte comprising a solvent having an index of refraction which is the same as or closely approaches that of water, are determined by liquid chromatography or capillary electrophoreses wherein the analyte is caused to flow through an optical waveguide. The waveguide is a rigid capillary having a refrctive index of less than 1.33. Measurement light is launched axially into the analyte by inserting an optical fiber, coupled to a light source, into one end of the waveguide.

Abstract: Water or some other aqueous fluid is employed as the light transmitting medium of a liquid-core fiber-optic wave guide employed as a spectrophotometer cell by employing, to define the core region, a polymer having a refractive index of less than 1.33. The light conducting channel defined by the aqueous fluid filled core may be a capillary or other suitably shaped vessel. The analysis of samples is accomplished by drawing a sample into the wave guide core region throughout the use of a fiber optic piston and thereafter delivering measurement light to the sample via the piston.

Abstract: Small quantities of liquid are conveyed, either for the purpose of filling micropipettes or to function as an electrolyte in an ion selective electrode, in a flexible non-metallic capillary tube which is mounted, at a first end, in an adapter fitting. The fitting defines a socket for coupling to a source of liquid, a hypodermic syringe for example, or for receiving an electrochemical half-cell which will contact an electrolyte in the tube. A filter may be interposed between the fitting and hypodermic syringe so as to frictionally engage both when the device is employed for filling micropipettes.

Abstract: A method and apparatus for electrical testing of membrane tissue employs a pair of rack sections which have cavities for receiving opposing end portions of the culture cup. The culture cup and rack sections are clamped together to form test chambers at opposing sides of the cup substrate on which the experimental tissue is grown. Electrode cartridges are inserted into axial bores of the receiving cavities to provide a test current through the membrane tissue. Integral connectors connect with conduits for passing irrigation streams through the test chambers.