Abstract: Systems and methods to assist a practitioner to confirm location of a distal tip of a needle within a patient include confirming tactile feedback from a needle insertion to a point of loss of resistance of fluid flow and by viewing a display showing color of a tissue plane at the distal tip of the needle at the point of loss of resistance.

Abstract: Systems and methods to assist a practitioner to confirm location of a distal tip of a needle within a patient include confirming tactile feedback from a needle insertion to a point of loss of resistance of fluid flow and by viewing a display showing color of a tissue plane at the distal tip of the needle at the point of loss of resistance.

Abstract: An apparatus for estimating the concentration of an aldehyde comprising a solid medium; a nucleophilic aromatic compound held on the medium; and an acid held on the medium and a method for detecting the presence of an aldehyde in a sample with the apparatus in which the sample is exposed at room temperature to a test medium to catalyze the formation of optically detectable quantities of a product within a time period of no more than 60 minutes and without applying any external heat to the sample or test medium, the test medium comprising a indicator that is a nucleophilic compound having acidic protons at the nucleophilic center and at least one acid, and measuring the optical changes that occur as a result of the catalysis.

Abstract: A method for detecting the presence of an aldehyde in a sample comprises steps of exposing the sample at room temperature to a test medium to catalyze the formation of optically detectable quantities of a product within a time period of no more than 60 minutes and without applying any external heat to the sample or test medium, the test medium comprising a indicator that is a nucleophilic compound having acidic protons at the nucleophilic center and at least one acid, and measuring the optical changes that occur as a result of the catalysis.

Abstract: A method for detecting the presence of an aldehyde in a sample comprises steps of exposing the sample at room temperature to a test medium to catalyze the formation of optically detectable quantities of a product within a time period of no more than 60 minutes and without applying any external heat to the sample or test medium, the test medium comprising a indicator that is a nucleophilic compound having acidic protons at the nucleophilic center and at least one acid, and measuring the optical changes that occur as a result of the catalysis.

Abstract: This invention relates to a system for printing and dispensing chemical reagents in precisely controlled volumes onto a medium at a precisely controlled location. A jetting tube, comprising an orifice at one end and a fluid receiving aperture at the other end, is concentrically mounted within a cylindrical piezo-electric transducer. The fluid receiving aperture is connected to a reservoir containing a selected reagent by means of a filter. The reservoir may be pressurized by a regulated air supply. An electrical signal of short duration is applied to the transducer. The pulse causes the transducer and the volume defined by the jetting tube to expand, thereby drawing in a small quantity of reagent fluid. The cessation of the pulse causes the transducer and the volume of the jetting tube to de-expand, thereby causing at least a substantially uniformly sized droplet of reagent fluid to be propelled through the orifice.

Abstract: Apparatus and method for analyzing a biological material such as blood serum to determine whether a substance indicative of disease is present. The apparatus utilizes a two-way valve construction for rinsing a cartridge containing the material under analysis at various operating stations.