Block Engineering, LLC

Tomas R Hirschfeld

Diane Eaton

Marvin Margoshes

An electronic image-encoder with an SEC vidicon in which the electron beam is positioned according to a coordinate pair stored as digital signals and applied as analog signals to the deflection coils of the vidicon. This permits the beam to read selected points on the vidicon target and the beam is blanked until the desired deflection signals are applied. In one version of the device, the deflection signals are simply voltages corresponding to the values of the digital signals. In another version, one digital signal is converted to an analog deflection voltage and a standard ramp is used as the other deflection voltage, the beam being turned on to read only after a time interval following initiation of the ramp, which interval is proportional to the other digital signal. A special application of the encoder incorporates a crossed-dispersion optical system for projecting several stacked spectral orders into the vidicon target. In all cases, the electron beam actuation provides an output signal corresponding to the image intensity at the point selected by the digital signal pair, and this output signal is digitized for storage, manipulation or display.

Digitally controlled electro-optical imaging system

Antigen-detecting reagents, suitable for detection of antigens present in liquids, biological fluids and tissues are prepared by covalently linking a large number of fluorescent dye molecules to the appropriate antibody through a polymeric backbone possessing reactive functional groups along the length of the chain.

Antigen detecting reagents

Reagents for the detection of specific reactants, such as antigens in biological fluids, comprising a polymer coupled to an antibody, the polymer having a plurality of dye molecules coupled thereto. The reagent is prepared by covalently linking an end functional group of polymers such as polyethylene amine to an antibody, typically through an aldehyde linkage, the polymer molecule having had a plurality of dye molecules, coupled to the polymer through side reactive sites.

Dye tagged reagent

A system for suppressing normal serum fluorescence in fluorescence immunoassay, in which in one embodiment, the immunoassay fluorescently tagged reaction product in a single sample is irradiated at a first wavelength which will excite fluorescence from the tagged product and then at a different wavelength which is not substantially in an absorption band of the fluorescent tag, the respective fluorescent emissions being detected and converted to electrical signals. The difference between the signals, adjusted for variation in serum fluorescence at the two wavelengths, is a function of the antigen titer. In an alternative form, the sample is irradiated at the first wavelength for a predetermined period of time commencing very shortly after the emission reaction is started, and the resulting signal from the detector is differentiated. In both instances, output signal due to serum fluorescence per se is suppressed.

Serum fluorescence suppression

A device for generating a multiplicity of proportionally diluted samples from a parent solution, which device has a plurality of chambers so connected that as the system is oscillated about a single axis, a proportional part of the fluid in each chamber is sampled and delivered to the next chamber.

Proportional diluter

A system for identifying within a mixed population, a group of microorganisms replicating in a culture medium specific to that group, which culture medium includes a fluorescence inhibitor which the group incorporates in their nucleic acid upon replication. In one embodiment, a sample of the microorganism population is dyed with two different fluorescent dyes which are specific to nucleic acid, the fluorescent emissivity of one of the dyes being reduced or quenched by the presence of the inhibitor in the dyed nucleic acid, the fluorescent emissivity of the other of the dyes being unaffected by the presence of the inhibitor. The ratio of intensities of the fluorescent emission from the two dyes is independent of the total nucleic acid content of each microorganism, but is dependent upon the extent of incorporation of the inhibitor into the nucleic acid, so serves as a marker or identifier of a replicated organism. In another embodiment of the invention, the sample of the population is dyed with but the one quenchable dye and the dyed organisms are exposed to high intensity radiation which very rapidly bleaches the dye. From the bleaching characteristics such as the time required for the fluorescent emission to decay from its initial intensity to l/e, or from the ratio of the initial intensity of emission to the integrated emission during bleaching, one can determine independently of the total amount of nucleic acid, changes in the quantum efficiency of the dye caused by the incorporation of the inhibitor in the nucleic acid, thereby identifying replicating organisms.

System for detecting growth in microorganisms

An improved system is desired for examining fluorescent material. The method comprises the steps of illuminating material with radiation at a fluorescent excitation wavelength of said material and at an intensity sufficient to cause bleaching of the material; detecting over a time interval commencing with initial illumination of the material, fluorescent emission produced by the material during bleaching of the latter by the radiation; and integrating over the interval the fluorescent emission detected during the bleaching of the material. Means are provided for illuminating the material to cause bleaching, for detecting fluorescent emission produced during bleaching, for measuring the decay time interval, and for integrating a signal from the detecting means over a time interval.

Fluorescence spectrometry employing excitation of bleaching intensity

An improved system is described for providing approximately equalized illumination at all points between first and second opposite portions of a total internally reflecting cell. The system comprises in addition to the cell, a source of radiation of at least one selected wavelength, means for directing the radiation along a plurality of paths, and means for introducing the radiation in at least two of the paths into first and second opposite portions of the cell. Means can be provided for varying the penetration angle of the radiation into the cell.

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Framingham, MA, United States of America

Tomas R Hirschfeld