E.i. Dupont De Nemours and Company

Scot D Abbott

Robert K Kobos

Wallace W Yau

Dale R Peterson

Herman W Levin

Henn Kilkson

Richard C Ebersole

Charles W Robertson, Jr

Michael A Luddy

An improved nucleic acid hybridization assay, relying on particle counting, is provided. Presence and quantity of target nucleic acid is determined by detecting, upon hybridization, signals associated with particle aggregation or coincident signals from particles and reporters.

Particle counting nucleic acid hybridization assays

A method for measuring hematocrit is provided. An electrochemically detectable marker is measured before and after the ratio of red cell volume to plasma volume is decreased. The measured concentrations are used in a mathematical formula to determine hematocrit value.

Electrochemical determination of hematocrit

A means for measuring either the intrinsic or inherent viscosity of a solute in solution with a solvent which is independent of flow rate and temperature fluctuations. The solution is passed through one capillary tube and the solvent through a second capillary, and the pressure drop across each is measured. Signals corresponding to each pressure drop measurement are fed to an amplification means such as a logarithmic amplifier where they are processed to determine either the intrinsic or inherent viscosity of the solute independent of flow rate and temperature fluctuations. The viscosity measuring means may also be used together with size exclusion chromatrography to determine the molecular weight distribution of polymer materials. It may also be used to measure the relative viscosity of a sample liquid and a reference liquid, and to determine the viscosity of the sample liquid independent of flow rate and temperature fluctuations.

Differential pressure capillary viscometer for measuring viscosity

A means for measuring either the intrinsic or inherent viscosity of a solute in solution with a solvent which is independent of flow rate and temperature fluctuations. The solution is passed through one capillary tube and the solvent through a second capillary, and the pressure drop across each is measured. Signals corresponding to each pressure drop measurement are fed to a logarithmic amplification means where they are processed to determine either the intrinsic or inherent viscosity of the solute independent of flow rate and temperature fluctuations. The viscosity measuring means may also be used together with size exclusion chromatrography to determine the molecular weight distribution of polymer materials. It may also be used to measure the relative viscosity of a sample liquid and a reference liquid, and to determine the viscosity of the sample liquid independent of flow rate and temperature fluctuations.

A particle counting apparatus includes a cuvette having a cylindrical bore therethrough and an exterior cylindrical surface the axis of which is perpendicular to the axis of the bore. The apparatus is adapted to detect light scattered from a particle that is small as compared to the wavelength of incident radiation and has an index of refraction close to that of the medium in which it is entrained.

Particle counting apparatus

A highly sensitive and rapid method for quantitatively assaying analytes in liquid media by directly measuring changes in particle size distribution of reagent particles having analyte insolubilized thereon in a system undergoing antibody-induced aggregation has been developed. The amount of analyte initially present can be determined by measuring the change in the distribution of particle size with time, the concentration of a particular size particle at a given time, the rate of formation of a particular size particle, or the steady-state maximum concentration for a particular size particle.

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Wilmington, DE, United States of America

Scot D Abbott