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enEnglish
Fluorescence definition: The property of emitting radiation while being irradiated. The radiation emitted is usually of longer wavelength than that incident or absorbed, e.g., a substance can be irradiated with invisible radiation and emit visible light. X-ray fluorescence is used in diagnosis.
fluorescence definition: absorption of a photon of light followed, after a delay, by emission of a photon of longer wavelength.
Fluorescence definition: Fluorescence is a luminescence (i.e., optical phenomenon) in cold bodies, in which a molecule absorbs a high-energy photon, and re-emits it as a lower-energy (longer-wavelength) photon. The energy difference between the absorbed and emitted photons ends up as molecular vibrations (heat).
Fluorescence Polarization definition: Measurement of the polarization of fluorescent light from solutions or microscopic specimens. It is used to provide information concerning molecular size, shape, and conformation, molecular anisotropy, electronic energy transfer, molecular interaction, including dye and coenzyme binding, and the antigen-antibody reaction.
fluorescence polarization definition: measurement of the polarization of fluorescent light from solutions or microscopic specimens; used to provide information concerning molecular size, shape, and conformation, molecular anisotropy, electronic energy transfer, molecular interaction, including dye and coenzyme binding, and the antigen-antibody reaction.
Fluorescent Dyes definition: Agents that emit light after excitation by light. The wave length of the emitted light is usually longer than that of the incident light. Fluorochromes are substances that cause fluorescence in other substances, i.e., dyes used to mark or label other compounds with fluorescent tags.
fluorescent dye/probe definition: dyes that emit light when exposed to light; the wave length of the emitted light is usually longer than that of the incident light; fluorochromes are substances that cause fluorescence in other substances, that is, dyes used to mark or label other compounds with fluorescent tags, and they are used as markers in biochemistry and immunology.
Microscopy, Fluorescence definition: Microscopy of specimens stained with fluorescent dye (usually fluorescein isothiocyanate) or of naturally fluorescent materials, which emit light when exposed to ultraviolet or blue light. Immunofluorescence microscopy utilizes antibodies that are labeled with fluorescent dye.
fluorescence microscopy definition: microscope that irradiates fluorescent materials or specimens with ultraviolet, violet, and occasionally blue light, causing the materials to fluoresce.
Fluorescence Microscopy definition: Microscopy of specimens stained with fluorescent dye (usually fluorescein isothiocyanate) or of naturally fluorescent materials, which emit light when exposed to ultraviolet or blue light (From MSH 2001).
Spectrometry, Fluorescence definition: Measurement of the intensity and quality of fluorescence.
fluorescence spectrometry definition: measurement of the intensity and quality of fluorescence
Spectrometry, X-Ray Emission definition: The spectrometric analysis of fluorescent X-RAYS, i.e. X-rays emitted after bombarding matter with high energy particles such as PROTONS; ELECTRONS; or higher energy X-rays. Identification of ELEMENTS by this technique is based on the specific type of X-rays that are emitted which are characteristic of the specific elements in the material being analyzed. The characteristic X-rays are distinguished and/or quantified by either wavelength dispersive or energy dispersive methods.
Fluorescence Polarization Immunoassay definition: Fluoroimmunoassay where detection of the hapten-antibody reaction is based on measurement of the increased polarization of fluorescence-labeled hapten when it is combined with antibody. The assay is very useful for the measurement of small haptenic antigens such as drugs at low concentrations.
Fluorescence polarization immunoassay (FPIA) definition: Immunoassay, Fluorescence Polarization
Fluorescence Activated Cell Sorting definition: Selection and deposition of individual cells of a particular phenotype from a mixed population into a separate tube or tissue culture plate by the use of a fluorescence-activated cell sorter (FACS) and fluorescently-labeled antibodies specific for surface molecules on the cells to be sorted.
In Situ Hybridization, Fluorescence definition: A type of IN SITU HYBRIDIZATION in which target sequences are stained with fluorescent dye so their location and size can be determined using fluorescence microscopy. This staining is sufficiently distinct that the hybridization signal can be seen both in metaphase spreads and in interphase nuclei.
fluorescent in situ hybridization definition: technique to determine positions of particular genes; fluorescent labeled probe is hybridized with denatured DNA in situ; by superimposition of grains, autoradiography identifies positions of corresponding genes.
Fluorescence in situ Hybridization definition: A physical mapping approach that uses fluorescent tags to detect hybridization of probes within metaphase chromosomes or less condensed somatic interphase chromatin. This technique can be used for identification of chromosomal abnormalities and for gene mapping.
Analyzers, Laboratory, Immunoassay, Fluorimetric definition: Immunoassay analyzers that attach fluorescent substances, which emit light at a wavelength after they have absorbed light at a different particular wavelength (either natural substances or dyes), as a label to either an antigen or an antibody and then measure the concentration of the ligand (the substance being analyzed) in the specimen under analysis, using the result of the antigen-antibody reaction. These analyzers usually include an autosampler, a reagent dispenser, a light source (e.g., a tungsten-halogen lamp), a filter or monochromator, and a detection system (fluorometer or spectrofluorometer); some also include computerized data processing devices. Some fluorimetric immunoassay analyzers use rare earth (lanthanide) chelates and time-resolved procedures to overcome background fluorescence. Fluorimetric analyzers usually have better sensitivity and reagent stability and use shorter assay time than photometric devices. Fluorimetric analyzers can quantify cardiac glycosides, antiasthmatics, antibiotics, antineoplastics, anticonvulsants, antiarrhythmics, and hormones.
FLUOROMETER definition: Immunofluorometer equipment for clinical use with its electrical power supply is a device used to measure the fluorescence of fluorochrome-labeled antigen-antibody complexes. The concentration of these complexes may be measured by means of reflected light. A beam of light is passed through a solution in which a fluorochrome has been selectively attached to serum protein antibody molecules in suspension. The amount of light emitted by the fluorochrome label is detected by a photodetector, which converts light energy into electrical energy. The amount of electrical energy registers on a readout system such as a digital voltmeter or a recording chart. This electrical readout is called the fluorescence value and is used to measure the concentration of antigen-antibody complexes.
FLUOROMETER, FOR CLINICAL USE definition: A fluorometer for clinical use is a device intended to measure by fluorescence certain analytes. Fluorescence is the property of certain substances of radiating, when illuminated, a light of a different wavelength. This device is used in conjunction with certain materials to measure a variety of analytes.
Fluorometers definition: Filter photometers that determine the emission of electromagnetic radiation from a substance at one wavelength after the substance has absorbed radiation at another wavelength. These instruments usually determine the presence of fluorescent compounds by placing the sample in a beam of light (most frequently ultraviolet), where fluorescent compounds are excited, emitting visible light. Their principal components are a stable light source (e.g., a mercury vapor lamp), a dispersing filter that removes visible light from the excited beam, a sample cuvette (glass for excited wavelengths above 320 nm, otherwise quartz), a secondary filter that removes scattered light from the beam, and usually a photomultiplier tube as a detector.
Spectrofluorometers definition: Spectrophotometers that determine the emission of electromagnetic radiation by a substance at one wavelength after it has absorbed radiation at another wavelength. These instruments usually determine the presence of fluorescent compounds by placing the sample in a beam of light (most frequently ultraviolet [UV]) where fluorescent compounds are excited, emitting visible light. Their principal components are a stable light source (e.g., a mercury vapor lamp), a grating that allows only a certain range of wavelengths to strike the sample, a sample cuvette (glass for exciting wavelengths above 320 nm, otherwise quartz), a secondary filter that removes scattered UV from the beam, and usually a photomultiplier tube as detector.
Fluorescence Spectroscopy definition: Fluorescent spectroscopy or fluorometry is a type of electromagnetic spectroscopy used for analyzing fluorescent spectra. It involves using a beam of light, usually ultraviolet light, that excites the electrons in molecules of certain compounds and causes them to emit light of a lower energy, typically, but not necessarily, visible light.
LIGHT, WOOD'S, FLUORESCENCE definition: A Wood's fluorescent lamp is a device intended for medical purposes to detect fluorescent materials (e.g., fluorescein pigment produced by certain microorganisms) as an aid in the identification of these microorganisms. The device aids in the diagnosis of disease.
FLUORESCENCE POLARIZATION IMMUNOASSAY, TOBRAMYCIN definition: A tobramycin test system is a device intended to measure tobramycin, an aminoglycoside antibiotic drug, in plasma and serum. Measurements obtained by this device are used in the diagnosis and treatment of tobramycin overdose and in monitoring levels of tobramycin to ensure appropriate therapy.
FLUORESCENCE POLARIZATION IMMUNOASSAY, CARBAMAZEPINE definition: A neuroleptic drugs radioceptor assay test system is a device intended to measure in serum or plasma the dopamine receptor blocking activity of neuroleptic drugs and their active metabolites. A neuroleptic drug has anti-psychotic action affecting principally psychomotor activity, is generally without hypnotic effects, and is a tranquilizer. Measurements obtained by this device are used to aid in determining whether a patient is taking the prescribed dosage level of such drugs.
FLUORESCENCE POLARIZATION IMMUNOASSAY, AMIBACIN definition: An amikacin test system is a device intended to measure amikacin, an aminoglycoside antibiotic drug, in serum and plasma. Measurements obtained by this device are used in the diagnosis and treatment of amikacin overdose and in monitoring levels of amikacin to ensure appropriate therapy.
FLUORESCENCE POLARIZATION IMMUNOASSAY, PHENOBARBITAL definition: A phenobarbitol test system is a device intended to measure phenobarbital, an antiepileptic and sedative-hypnotic drug, in human specimens. Measurements obtained by this device are used in the diagnosis and treatment of phenobarbital use or overdose and in monitoring levels of phenobarbital to ensure appropriate therapy.
FLUORESCENCE POLARIZATION IMMUNOASSAY, THEOPHYLLINE definition: A theophylline test system is a device intended to measure theophylline (a drug used for stimulation of the muscles in the cardiovascular, respiratory, and central nervous systems) in serum and plasma. Measurements obtained by this device are used in the diagnosis and treatment of theophylline overdose or in monitoring levels of theophylline to ensure appropriate therapy.
fluorescence resonance energy transfer definition: method used to evaluate interactions and different conformational states of molecules.
Fluorescence Resonance Energy Transfer definition: A type of FLUORESCENCE SPECTROSCOPY using two FLUORESCENT DYES with overlapping emission and absorption spectra, which is used to indicate proximity of labeled molecules. This technique is useful for studying interactions of molecules and PROTEIN FOLDING.
MICROSCOPE, FLUORESCENCE/U.V. definition: Microscopes and accessories are optical instruments used to enlarge images of specimens, preparations, and cultures for medical purposes. Variations of microscopes and accessories (through a change in the light source) used for medical purposes include the following: (1) Phase contrast microscopes, which permit visualization of unstained preparations by altering the phase relationship of light that passes around the object and through the object. (2) Fluorescense microscopes, which permit examination of specimens stained with fluorochromes that fluoresce under ultraviolet light. (3) Inverted stage microscopes, which permit examination of tissue cultures or other biological specimens contained in bottles or tubes with the light source mounted above the specimen.
Microscopes, Light, Laboratory, Fluorescence definition: Laboratory light microscopes in which light (typically ultraviolet) that has been absorbed by the specimen and reemitted at a longer wavelength is observed (as visible light) through the eyepiece. Appropriate filters are used to select the correct wavelength of incoming beam to excite the fluorescent compound and eliminate the unwanted incident wavelength from the fluorescent light source (i.e., the specimen). Some fluorescence microscopes can also be configured for bright-field and/or phase-contrast observation. These microscopes are used in histopathology and microbiology, commonly in conjunction with fluorescent dyes. The use of a vertical illuminator and dichroic mirrors (epifluorescence) offers some advantages over fluorescence microscopy using transmitted illumination.
Microscopy, Fluorescence, Multiphoton definition: Fluorescence microscopy utilizing multiple low-energy photons to produce the excitation event of the fluorophore. Multiphoton microscopes have a simplified optical path in the emission side due to the lack of an emission pinhole, which is necessary with normal confocal microscopes. Ultimately this allows spatial isolation of the excitation event, enabling deeper imaging into optically thick tissue, while restricting photobleaching and phototoxicity to the area being imaged.
Fluorescence Recovery After Photobleaching definition: A method used to study the lateral movement of MEMBRANE PROTEINS and LIPIDS. A small area of a cell membrane is bleached by laser light and the amount of time necessary for unbleached fluorescent marker-tagged proteins to diffuse back into the bleached site is a measurement of the cell membrane's fluidity. The diffusion coefficient of a protein or lipid in the membrane can be calculated from the data. (From Segen, Current Med Talk, 1995).
fluorescence recovery after photobleaching definition: method used to study lateral movements of membrane proteins and lipids; a small area of a cell membrane is bleached by laser light and the amount of time necessary for unbleached fluorescent marker tagged proteins to diffuse back into the bleached site is a measurement of the cell membrane's fluidity.
LASER,FLUORESCENCE CARIES DETECTION definition: A laser fluorescence caries detection device is a laser, a fluorescence detector housed in a dental handpiece, and a control console that performs device calibration, as well as variable tone emitting and fluorescence measurement functions. The intended use of the device is to aid in the detection of tooth decay by measuring increased laser induced fluorescence.
Fluorescence Bronchoscopy definition: Fluorescence bronchoscopy is based on the fact that normal tissue fluoresces differently than abnormal tissue when exposed to an appropriate wavelength of light and that this difference can be detected.
Laser Fluorescence definition: A method used to aid in the detection of tooth decay by measuring fluorescence using a laser.
Fluorescence Units definition: A measurement of the amount of luminescence emitted from a given sample due to the absorption of a photon by that sample.
Arbitrary Fluorescence Units definition: Arbitrary unit(s) of fluorescent luminescence.
fluorescence definition: [1] Fluoreszenz
 
 
deGerman
Fluoreszenz definition: [1] Unter dem Begriff versteht man eine charakteristische Leuchterscheinung, eben die sog. Fluoreszenz, die bei Beleuchtung durch ultraviolettes Licht hervorgerufen wird. Während solche fluoreszierende Materialien nur bei entsprechender Bestrahlung in einer für sie typischen Farbe strahlen, leuchten phosphoreszierende Stoffe auch nach aussetzender Bestrahlung noch eine Zeit lang nach.
 
frFrench
fluorescence definition: Propriété d’un corps fluorescent.