9255results about "Raman scattering" patented technology

A method and apparatus are provided for the determination of levels of carotenoids and similar chemical compounds in biological tissue such as living skin. The method and apparatus provide a noninvasive, rapid, accurate, and safe determination of carotenoid levels which in turn can provide diagnostic information regarding cancer risk, or can be a marker for conditions where carotenoids or other antioxidant compounds may provide diagnostic information. Such early diagnostic information allows for the possibility of preventative intervention. The method and apparatus utilize the technique of resonance Raman spectroscopy to measure the levels of carotenoids and similar substances in tissue. In this technique, laser light is directed upon the area of tissue which is of interest. A small fraction of the scattered light is scattered inelastically, producing the carotenoid Raman signal which is at a different frequency than the incident laser light, and the Raman signal is collected, filtered, and measured. The resulting Raman signal can be analyzed such that the background fluorescence signal is subtracted and the results displayed and compared with known calibration standards.

Filtering of optical fibers and other related devices. High-energy methods for depositing thin films directly onto the ends of optical fibers can be used to produce high-quality, high-performance filters in quantity at a reasonable cost. These high-quality filters provide the high performance needed for many demanding applications and often eliminate the need for filters applied to wafers or expanded-beam filtering techniques. Having high-quality filters applied directly to optical fiber and faces permits production of high-performance, micro-sized devices that incorporate optical filters. Devices in which these filters may be used include spectroscopic applications including those using fiber optic probes, wavelength division multiplexing, telecommunications, general fiber optic sensor usage, photonic computing, photonic amplifiers, pump blocking and a variety of laser devices.

PCT No. PCT/GB96/01830 Sec. 371 Date Apr. 21, 1998 Sec. 102(e) Date Apr. 21, 1998 PCT Filed Jul. 25, 1996 PCT Pub. No. WO97/05280 PCT Pub. Date Feb. 13, 1997The invention relates to the detection of target nucleic acids or nucleic acid units in a sample, by obtaining a SER(R)S spectrum for a SER(R)S-active complex containing, or derived directly from, the target. The complex includes at least a SER(R)S-active label, and optionally a target binding species containing a nucleic acid or nucleic acid unit. In this detection method, the concentration of the target present in the SER(R)S-active complex, or of the nucleic acid or unit contained in the target binding species in the SER(R)S-active complex, is no higher than 10-10 moles per liter. Additionally or alternatively, one or more of the following features may be used with the method: i) the introduction of a polyamine; ii) modification of the target, and/or of the nucleic acid or nucleic acid unit contained in the target binding species, in a manner that promotes or facilitates its chemi-sorption onto a SER(R)S-active surface; iii) inclusion of a chemi-sorptive functional group in the SER(R)S-active label. The invention also provides SER(R)S-active complexes for use in such a method, a kit for use in carrying out the method or preparing the complexes and a method for sequencing a nucleic acid which comprises the use of the detection method to detect at least one target nucleotide or sequence of nucleotides within the acid.

Methods and system for noninvasive determination of tissue analytes utilize tissue properties as reflected in key features of an analytical signal to improve measurement accuracy and precision. Physiological conditions such as changes in water distribution among tissue compartments lead to complex alterations in the measured analytical signal of skin, leading to a biased noninvasive analyte measurement. Changes in the tissue properties are detected by identifying key features in the analytical signal responsive to physiological variations. Conditions not conducive to the noninvasive measurement are detected. Noninvasive measurements that are biased by physiological changes in tissue are compensated. In an alternate embodiment, the analyte is measured indirectly based on natural physiological response of tissue to changes in analyte concentration. A system capable of such measurements is provided.

The present invention relates to vacuum processing systems in which process gases are introduced in a process chamber and are exhausted through a vacuum processing system exhaust path. Deposits made by the exhausted gas are reduced or eliminated by introducing a reactive gas upstream of the device affected by deposits. The amount of introduced reactive gas is controlled by measuring gas phase concentrations of exhausted gas components upstream and downstream of the affected device, and, from those measurements, determining whether the components are being consumed in deposits on the affected device.

An optical sensor and method for use with a visible-light laser excitation beam and a Raman spectroscopy detector, for detecting the presence chemical groups in an analyte applied to the sensor are disclosed. The sensor includes a substrate, a plasmon resonance mirror formed on a sensor surface of the substrate, a plasmon resonance particle layer disposed over the mirror, and an optically transparent dielectric layer about 2-40 nm thick separating the mirror and particle layer. The particle layer is composed of a periodic array of plasmon resonance particles having (i) a coating effective to binding analyte molecules, (ii) substantially uniform particle sizes and shapes in a selected size range between 50-200 nm (ii) a regular periodic particle-to-particle spacing less than the wavelength of the laser excitation beam. The device is capable of detecting analyte with an amplification factor of up to 10¹²-10¹⁴, allowing detection of single analyte molecules.

Apparatus and method for determining at least one parameter, e. g., concentration, of at least one analyte, e. g., urea, of a biological sample, e. g., urine. A biological sample particularly suitable for the apparatus and method of this invention is urine. In general, spectroscopic measurements can be used to quantify the concentrations of one or more analytes in a biological sample. In order to obtain concentration values of certain analytes, such as hemoglobin and bilirubin, visible light absorption spectroscopy can be used. In order to obtain concentration values of other analytes, such as urea, creatinine, glucose, ketones, and protein, infrared light absorption spectroscopy can be used. The apparatus and method of this invention utilize one or more mathematical techniques to improve the accuracy of measurement of parameters of analytes in a biological sample. The invention also provides an apparatus and method for measuring the refractive index of a sample of biological fluid while making spectroscopic measurements substantially simultaneously.

An apparatus and method are provided to verify the composition of a medical fluid in a fluid infusion channel by comparison with clinician-entered input. Light is transmitted through the channel and detected by a sensor that generates signals representative of the spectral data of the light detected. A processor compares the spectral data of the light detected to the spectral data associated with the expected contents of the channel to verify that the correct fluid is being infused.

An organic or organoelement, linear or branched, monomeric or polymeric composition of matter having a Raman-active component in the form of particles. The particles having a maximum dimension of 50 mum. The Raman-active compound is applied to a substrate. When the Raman-active compound is exposed to a laser light wavelength which is batochromically well beyond a spectral region of maximum absorbance of said Raman-active compound, Raman scattering can be detected.

The invention provides a preparation method of graphene, and particularly relates to a method for preparing biomass graphene employing cellulose as a raw material. The specific preparation method comprises the following steps: 1, preparing a catalyst solution; 2, carrying out ionic coordination and high-temperature deoxidization on cellulose and a catalyst, so as to obtain a precursor; 3, carrying out thermal treatment; 4, carrying out acid treatment, and drying to obtain the graphene, wherein the prepared graphene is uniform in morphology, has a single-layer or multi-layer two-dimensional layered structure; the dimension is 0.5-2 microns; and the electrical conductivity is 25,000-45,000S/m. The preparation method is simple in preparation technology, low in cost, high in yield, high in production safety, and controllable in product dimension and physical property; industrialized production can be realized; the graphene prepared by the method can be applied to electrode materials of super capacitors and lithium ion batteries, and can also be added to resin and rubber as an additive; and the physical property of the material can be improved.

The present invention discloses a method and apparatus and method for achieving non-invasive measurement of analytes from human and animal blood through the skin using Raman lightwave technology. The apparatus includes a hydraulic tissue permeation unit, which controls the amount of blood in the laser tissue interaction region. Two or more spectra are obtained at different blood levels. These spectra are used to improve the measurements.

Methods and systems are disclosed for detecting overheating in an optical device before harmful consequences, such as severe local heating, can result. In one embodiment of the invention, a blackbody emitter is disposed in close proximity to a therapeutic optical fiber to absorb therapeutic radiation at a fault and re-emit blackbody (infrared) radiation. The emitter can be coupled to the fiber but, during normal operation, lies outside the optical path between the output of the laser radiation and the site of treatment. Systems and catheters incorporating such emitters are also described for effective monitoring of the laser power transmitted along the optical fiber within the phototherapy device.

NERS-active structures for use in Raman spectroscopy include protrusions extending from a surface of a substrate. A Raman signal-enhancing material is disposed on at least one surface of a first protrusion and at least one surface of a second protrusion. The Raman signal-enhancing material disposed on the first protrusion projects laterally in a direction generally towards the second protrusion, and the Raman signal-enhancing material disposed on the second protrusion projects laterally in a direction generally towards the first protrusion. At least a portion of the Raman signal-enhancing projecting from the first protrusion and at least a portion of the Raman signal-enhancing material projecting from the second protrusion may be separated by a distance of less than about 10 nanometers. Raman spectroscopy systems include such NERS-active structures, and methods for performing Raman spectroscopy include irradiating an analyte proximate such a NERS-active structure and detecting Raman-scattered radiation scattered by the analyte.

The detection of a chemical specie of interest is accomplished by immobilizing sensing molecules on the inner wall of a liquid core optical waveguide, the waveguide comprising a capillary tube and the sensing molecules being selected to interact with the specie of interest carried by the liquid which forms the waveguide core. The interaction produces a change in an optical characteristic of the waveguide which may be detected by illuminating the waveguide with analysis light.

Surface-enhanced Raman spectroscopy (SERS) uses nanoscale metal particles (SERS-active particles) or surface roughness to enhance the Raman signal of Raman-active analytes contacting the surface. SERS sandwich particles contain SERS-active particles sandwiching a Raman-active substance and serve as optical tags. Preferably, the particles are rod-shaped, with each layer (SERS-active and Raman-active) formed as a distinct stripe of the particle. These freestanding particles can be derivatized with surface ligands capable of associating with analytes of interest in, for example, a biological sample. The acquired Raman spectrum of the particle encodes the identity of the ligand. Because of the simplicity and intensity of Raman spectra, highly multiplexed assays are capable using SERS particles with different Raman-active species.

The present invention further relates to the selection of the specific filter combinations, which can provide sufficient information for multivariate calibration to extract accurate analyte concentrations in complex biological systems. The present invention also describes wavelength interval selection methods that give rise to the miniaturized designs. Finally, this invention presents a plurality of wavelength selection methods and miniaturized spectroscopic apparatus designs and the necessary tools to map from one domain (wavelength selection) to the other (design parameters). Such selection of informative spectral bands has a broad scope in miniaturizing any clinical diagnostic instruments which employ Raman spectroscopy in particular and other spectroscopic techniques in general.

A scanning microscope having a laser outputting an excitation laser beam and a fiber member having a first core and a second core. The second core is generally disposed within the first core and is operable to receive the excitation laser beam from the laser and transmit the excitation laser beam to a sample to be tested. A moveable stage supports an end of the fiber member and/or a sample to be tested and is operable to move the end of the fiber member and the sample to be tested relative to each other.

An apparatus for evaluating a target of interest of a living subject. In one embodiment, the apparatus has a first light source for generating a broadband light, a second light source for generating a monochromatic light, a beamsplitter optically coupled to the first light source for receiving the broadband light and splitting it into a reference light and a sample light, a reference arm optically coupled to the beamsplitter for receiving the reference light and returning it into the beamsplitter, and a probe having a working end placed proximal to a target of interest of a living subject, optically coupled to the beamsplitter and the second light source for receiving the sample light and the monochromatic light, delivering them from the working end to the target of interest, collecting from the working end a backscattering light and a Raman scattering light that are obtained from interaction of the sample light and the monochromatic light with the target of interest, respectively, and returning the backscattering light into the beamsplitter so as to generate an interference signal between the returned backscattering light and the returned reference light in the beamsplitter.

A non-invasive method for analyzing the blood-brain barrier includes obtaining a Raman spectrum of a selected portion of the eye and monitoring the Raman spectrum to ascertain a change to the dynamics of the blood brain barrier. Also, non-invasive methods for determining the brain or blood level of an analyte of interest, such as glucose, drugs, alcohol, poisons, and the like, comprises: generating an excitation laser beam (e.g., at a wavelength of 600 to 900 nanometers); focusing the excitation laser beam into the anterior chamber of an eye of the subject so that aqueous humor, vitreous humor, or one or more conjunctiva vessels in the eye is illuminated; detecting (preferably confocally detecting) a Raman spectrum from the illuminated portion of the eye; and then determining the blood level or brain level (intracranial or cerebral spinal fluid level) of an analyte of interest for the subject from the Raman spectrum. In certain embodiments, the detecting step may be followed by the step of subtracting a confounding fluorescence spectrum from the Raman spectrum to produce a difference spectrum; and determining the blood level and/or brain level of the analyte of interest for the subject from that difference spectrum, preferably using linear or nonlinear multivariate analysis such as partial least squares analysis. Apparatus for carrying out the foregoing methods are also disclosed.

The present invention provides a sample tank having a window for introduction of electromagnetic energy into the sample tank for analyzing a formation fluid sample down hole or at the surface without disturbing the sample. Near infrared, mid infrared and visible light analysis is performed on the sample to provide a downhole in situ or surface on site analysis of sample properties and contamination level. The onsite analysis comprises determination of gas oil ratio, API gravity and various other parameters which can be estimated by a trained neural network or chemometric equation. A flexural mechanical resonator is also provided to measure fluid density and viscosity from which additional parameters can be estimated by a trained neural network or chemometric equation. The sample tank is pressurized to obviate adverse pressure drop or other effects of diverting a small sample.