Abstract:
This invention relates to methods for processing in vivo skin auto-fluorescence spectra for determining blood glucose levels. The invention also relates to methods of classifying cells or tissue samples or quantifying a component of a cell or tissue using a multivariate classification or quantification model.
Abstract:
The present invention relates to the exploration for and exploitation of formation hydrocarbons. According to the invention, a sample of material, representative of the impregnation with hydrocarbons of the rocks passed through, is taken during a drilling operation, with which sample a value of an emission flux, representative of the concentration of the fluorescent elements in the sample, and a value of a fluorescence quotient, which reflects the nature of the hydrocarbons present in the sample, are determined by spectrofluorimetry. The invention finds its application in analytical laboratories and on the drilling sites of petroleum production fields.
Abstract:
Methods of screening for a tumor or tumor progression to the metastatic state are a provided. The screening methods are based on the characterization of DNA by principal components analysis of spectral data yielded by Fourier transform-infrared spectroscopy of DNA samples. The methods are applicable to a wide variety of DNA samples and cancer types.
Abstract:
A method and an apparatus for determining the content of a constituent of blood of an individual are disclosed. In the method a whole blood stream is extracted from a blood vessel of said individual, the stream being directed through a path defining a substantially non-varying flow-through area wherein is provided a flow-through measuring cuvette including opposite first and second optical transparent surface parts defining an optical transmission path of the order of 0.5-2.0 mm. The whole blood stream flowing through the measuring cuvette is irradiated by irradiating the first optical transparent surface part of the measuring cuvette with multi-wavelength near infrared light. The near infrared absorption spectrum is detected and the content of the constituent is quantified on the basis of the detected near infrared absorption data. The method is particularly suited for measuring constituents of whole blood in an extracorporeal loop, for example in hemodialysis.
Abstract:
A sample having a specific optical path length of 1 to 15 mm is irradiated with near infrared of two or more wavelengths selected from 700 to 1200 nm to determine constituents of dairy products. Preferably, a pair of specific wavelengths comprise a first wavelength having a high correlation with a target constituent and a second wavelength having a low correlation with the target constituent or comprise wavelengths both having high correlations with the target constitutent. Quantities of near infrared of these two specific wavelengths transmitted by the sample are measured to determine absorbencies and a multiple linear regression equation is used to calculate the constituent on the basis of the absorbencies.
Abstract:
The energy transfer efficiency of a donor-acceptor pair of fluorescent dyes can be determined by first measuring the fluorescence and absorption spectra of donor-protein, acceptor-protein, mixture of donor-protein and acceptor-protein, and donor-acceptor-protein conjugates, then separating the respective spectra into their respective donor-protein complex and acceptor-protein complex components using multiple linear regression, and then determining the transfer efficiency on the basis of the quenching of the donor fluorescence based on the spectral data thus obtained.
Abstract:
A spectrometric method for determining a physical or a chemical target quantity by performing the photometric measurement at plural wavelengths predetermined which includes the steps of measuring variation vectors by varying error variation factors by predetermined units which are defined in a space having a dimension equal to the number of the plural wavelengths, seeking for a subspace of the space which is orthogonal to all variation vectors, performing the photometric measurement for samples having known values of the target quantity, projecting vectors obtained from the photometric measurement for samples on the subspace and calculating a calibration curve using data obtained by the projection on the subspace.
Abstract:
A method for chemistry systems analysis to identify the performance of the functional components of the system, specifically, those of volumes dispensed and optical linearity. Employing a linear regression comparison between predetermined absorbance values, calculated from Beer's Law, and absorbance values obtained from the optical system under test, a value correction constant derived from the regression comparison may be applied to all subsequent absorbance values. Absorbance values, obtained from the optical system as a result of analyzing dilutions are by the pipetting system of material having a greater concentration but the same molar absorbtivity constant as the material used for the linearity evaluation, can be corrected to a value that does not reflect any optical system bias, and may be considered as the divident for the function of converting absorbance values into volumes dispensed. The divisor of the convertion function will be derived from the predetermined absorbance of the concentrate, using Beer's Law, and dividing that by the total volume requested by the volumes evaluation, leaving an absorbance value that equals a lul delivery. The volume dispensed by the pipetting system may then be calculated by dividing the corrected absorbance value by the lul absorbance value, yielding a quotient identifying the actual volume delivered.
Abstract:
An apparatus and method for determining the photosynthetic activity of a plant by determining the chlorophyll fluorescence of the plant is provided. The apparatus includes a light impermeable housing, a light to illuminate the housing, a light intensity in the housing and to adjust the light intensity controller. The light intensity may be between zero and 700 micromoles of photons per square meter per second. The monitor may be a photodiode protected by light filters which permit only light of wavelengths corresponding to plant fluorescence emission to pass to the photodiode. A computer analysis of the data obtained, corrects for Dark and Straylight signals in the housing and normalizes the data by correcting for the Fo fluorescence. A method of estimating Fo is provided which includes illuminating a light impermeable chamber housing a plant with light of a pre-determined intensity, measuring the fluorescence emission, determining the slope of a first regression line prior to full opening of the shutter; determining the slope of a second regression line of measurements after the shutter is fully opened and determining the intersecting point between these two lines. A method of determining the corrected and normalized fluorescence emissions from a plant is provided.