E.i. Dupont De Nemours and Company

James M Prober

Rudy J Dam

Charles W Robertson, Jr

George L Trainor

Frank W Hobbs

Michael P Perry

Kostantinos Kourtakis

Larry Eugene Steenhoek

James E Davis

Edwin R Hendrickson

Paul Douglas Stull

Mark E Faulhaber

Kevin Michael Croker

Alan M Hochberg

Michael B Damore

Xiumin Cui

Xueping Jiang

A microsphere for use in a bioassay comprising a glass core coated with a nanoparticle composite comprising a bioactive probe is provided. The nanoparticle composite coating enhances the density of bioprobe loading on the surface of the microspheres, resulting in enhanced dynamic range and sensitivity in bioassays. The particle may be used in detection systems where resonant light scattering properties of the particle are useful.

Nanoparticle composite-coated glass microspheres for use in bioassays

Microparticle-based analytical methods, systems and applications are provided. Specifically, the use of resonant resonant light scattering as an analytical method for determining either or both a particle's identity and the presence and optionally, the concentration of one or more particular target analytes is described. Applications of these microparticle-based methods in biological and chemical assays are also disclosed.

Resonant light scattering microparticle methods

A method for controlling the properties of the product polymer of a polymerization process to improve the process productivity and product quality in both batch and continuous production of polyamides.

Process control method for vented polymerizers

A DNA sequencing system and method are described to detect the presence of radiant energy emitted from different excited reporter dye-labeled species (DNA fragments) following separation in time and/or space, and the identity of the species which emit radiant energy closely spaced in wavelength. Functions of the emitted energy are obtained which vary over the wavelengths of the closely spaced spectra in different senses and the functions ratioed, whereby the ratio is indicative of the identity of the DNA fragments. The emitting portion of the reporter-labeled DNA fragment is preferably one of a family of fluorescent dyes based on 9-carboxyethyl-6-hydroxy-3-oxo-3H-xanthene. These xanthene dyes are covalently attached to the DNA fragments through the carboxylic acid functionality, preferably via an amide linkage. The dyes may be protected by including an alkoxy group at the 9-position. A spacer may be inserted between the dye and the amine. The fluorescent dye preferably is attached to the DNA chain terminators and provides many advantages. Thus only DNA sequencing fragments resulting from bona fide termination events will carry a reporter. The DNA sequencing may also be labeled using the xanthene dyes which have general utility as fluorescent labels. Also acyclonucleoside triphosphates are described as being useful as chain terminators in DNA sequencing using a modification of the Sanger method.

Method, system and reagents for DNA sequencing

Method systems and reagents for DNA sequencing

A DNA sequencing system and method are described to detect the presence of radiant energy emitted from different excited reporter dye-labeled species (DNA fragments) following separation in time and/or space, and the identity of the species which emit radiant energy closely spaced in wavelength. Functions of the emitted energy are obtained which vary over the wavelengths of the closely spaced spectra in different senses and the functions ratioed, whereby the ratio is indicative of the identity of the DNA fragments. The emitting portion of the reporter-labeled DNA fragment is preferably one of a family of fluorescent dyes based on 9-carboxyethyl-6-hydroxy-3-oxo-3 H-xanthene. These xanthene dyes are covalently attached to the DNA fragments through the carboxylic acid functionality, preferably via an amide linkage. The dyes may be protected by including an alkoxy group at the 9-position. A spacer may be inserted between the dye and the amine. The fluorescent dye preferably is attached to the DNA chain terminators and provides many advantages. Thus only DNA sequencing fragments resulting from bona fide termination events will carry a reporter. The DNA sequencing may also be labeled using the xanthene dyes which have general utility as fluorescent labels. Also acyclonucleoside triphosphates are described as being useful as chain terminators in DNA sequencing using a modification of the Sanger method.

The method of this invention obtains the underlying peak shapes of two signal spectrums whose ratios are representative of different species. The underlying peak shapes are fitted to the signal spectrums in a way that yield accurate ratios. The ratios are accurate even when the location of the peaks are not precisely known.

Method for determining DNA sequences

A system for detecting the radiant energy emitted from different closely spaced species includes two detectors each having a large entrance angle for receiving the radiant energy, and wavelength selective filters between the detector and species, the transmission vs. wavelength characteristics being complementary, and means for ratioing functions of the detector outputs, the ratio being indicative of the identity of the species.

Scanning fluorescent detection system

Insufficient finish level on a yarn may be detected by monitoring the temperature of a stationary surface over which the yarn runs and observing a rise in temperature above that seen when a normal fixed level of finish is present on the yarn.

Method for indicating an insufficient level of yarn finish

Presence and location of infrared radiation-absorbing or emitting gases in the atmosphere can be ascertained by means of an infrared imaging-analyzing means which views a given scene and receives infrared radiation therefrom. Analytic and reference beams are produced, the latter having reduced sensitivity to the gas of interest, and are converted to electric signals, which are processed in real time to provide a signal corresponding to their ratio. This ratio signal is further processed to generate an image, which can be displayed and viewed. This technique is particularly suitable for surveying large areas for seepage of methane or other hydrocarbon gases from underground gas and/or oil deposits.

Method and apparatus for remotely detecting gases in the atmosphere

An accurate method of determining by plasma chromatography the concentration of an ionizable gaseous or volatile chemical species A in air or another gaseous medium. Small, known increments of species A plus, optionally, another calibrant species are introduced in turn into the plasma chromatograph together with the unknown sample; and the respective changes of the amplitude or area of a characteristic ion peak of species A in the unknown sample are measured. The second, optical calibrant, which is different from species A, must have similar kinetic characteristics but a different ion mobility from the ion formed by A. By means of this technique, inaccurate readings caused by background concentration variations are significantly reduced.

Method of determining small concentrations of chemical compounds by

Method and apparatus for compensating spurious radiation detector signal output variations during operation of an infrared (IR) analyzer.

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Wilmington, DE, United States of America

James M Prober