Abstract:
The combination of a cuvette for receiving a medium undergoing change in optical characteristics which change modifies the energy level of a ray of energy passing through the medium and wherein the cuvette is provided with integrally formed first and second ray modifying optical means, such as collimating and collecting lens, wherein the first ray modifying optical means receives and modifies the ray in a first manner, such as by collimation, and transmits the ray into the medium and wherein the second ray modifying optical means receives and modifies the ray in a second manner, such as by collection, upon the ray passing through the medium and transmits the ray from the cuvette; and an electrical circuit including photoemissive and photosensitive means, such as a photoemitter and photodetector, wherein the photoemissive means is in intimate optical contact with the first ray modifying optical element of the cuvette and wherein the photosensitive means is in intimate optical contact with the second ray modifying means.
Abstract:
A method for qualitative and quantitative determination of agglutination in immunoreactive systems, and for determining the concentration of the immunoreactive components of such system, which method comprises introducing a fluid biological test specimen and a reagent therefor (e.g., latex spheres) into a reaction zone in an image cell and evenly mixing and incubating the mixture thereby forming agglutinated particles. The reaction zone is then transilluminated and the light beams transmitted therethrough are imaged on an image sensor. Dark areas are formed on the surface of the image sensor which are measured, preferably electronically. This procedure is repeated for a reference specimen and the total dark imaged area is compared with the total dark area obtained for the unknown specimen for qualitative determination.In order to obtain the concentration of the immunoreactive component in the unknown specimen, the foregoing procedure is repeated for at least two specimens with known antibody concentrations, one of which may be a negative control. The concentration of the immunoreactive component of the unknown sample is then determined from the total dark imaged area thereof and the relationship between the total dark imaged areas of the known specimen and their respective concentrations.
Abstract:
The apparatus comprises a plurality of stationary cuvettes, a chamber for the fluid to be evaluated, means for placing the chamber in fluid communication with each of the cuvettes and for permitting the flow of fluid from the chamber into each of the cuvettes, a plurality of optical transmitting means in registration with each of the cuvettes for transmitting a beam of radiant energy through each of the cuvettes, and detector means for intercepting each of the beams of radiant energy and for measuring any optical changes in the radiant energy passing through the fluid in each of the cuvettes.The chamber for the fluid, the plurality of cuvettes and the fluid communication means are all housed within, preferably, a disposable, self-contained cartridge of unitary construction. The cartridge is mountable within a carriage that houses the transmitting and detector means of the apparatus. The chamber which forms the upper portion of the cartridge can be prefilled with bacterial suspension. Periodically, during the growth of the subject bacteria the suspensions are agitated by suitable means. Samples of antibiotics of varying potency are placed in the cuvettes. The cartridge is mounted in the carriage. On a signal from the detector means a portion of the suspension passes into each of the cuvettes to begin the antibiotic titer which is evaluated by means of the transmitting and detector means and associated electronic circuitry.
Abstract:
A method of determining minimum inhibitory concentration (MIC) of an antibiotic by continuously measuring the change in optical properties in response to the bacterial growth rate of a bacterial suspension in the absence and the presence of the antibiotic. The method is carried out in an automatic biological fluid analyzer.
Abstract:
Baseline correction for a pulse train is achieved by arranging the source generating the pulse train in series circuit with a switch and by rendering the switch selectively conductive during time periods coextensive with the separation interval between successive pulses in the pulse train. The switch output is stored and is subtractively combined with the pulse train. Switching control is effected by a signal generator which also time controls generation of the pulse train.