| HT | Hashimoto thyroiditis; hearing test; hearing threshold; heart; heart transplantation, heart transpla... |
|---|---|
| HREM | high-resolution electron microscopy |
| HRTEM | high-resolution transmission electron microscopy |
| HVTEM | high-voltage transmission electron microscopy |
| HCD | health care delivery; heavy-chain disease; high-calorie diet; high-carbohydrate diet; homologous can... |
| video microscopy | <technique> Microscopy that takes advantage of video as an imaging, image processing, analysing, or controlling device. (05 Aug 1998) |
|---|---|
| phase contrast microscopy | <investigation> A simple nonquantitative form of interference micoscopy of great utility in visualising live cells. Small differences in optical path length due to differences in refractive index and thickness of structures are visualised as differences in light intensity. (18 Nov 1997) |
| microscopy | <technique> The science of the interpretive use, and applications of microscopes. (05 Aug 1998) |
| microscopy, atomic force | Microscopy in which a probe systematically rides across the surface of a sample being scanned in a raster pattern. The vertical position is recorded as a spring attached to the probe rises and falls in response to peaks and valleys on the surface. A microcomputer keeps track of the vertical excursions as a function of the position of the probe in the horizontal plane and presents the sample's image. (12 Dec 1998) |
| microscopy, confocal | A light microscopic technique in which only a small spot is illuminated and observed at a time. An image is constructed through point-by-point scanning of the field in this manner. Light sources may be conventional or laser, and fluorescence or transmitted observations are possible. (12 Dec 1998) |
| microscopy, electron | Visual and photographic microscopy in which electron beams with wavelengths thousands of times shorter than visible light are used in place of light, thereby allowing much greater magnification. (12 Dec 1998) |
| microscopy, electron, scanning | Microscopy in which the object is examined directly by an electron beam scanning the specimen point-by-point, giving the surface image a three-dimensional quality. (12 Dec 1998) |
| microscopy, electron, scanning transmission | A type of electron microscopy which scans with an extremely narrow beam that is transmitted through the sample. The detection apparatus produces an image whose brightness depends on the atomic number of the sample. It should not be confused with microscopy, electron scanning nor with microscopy, electron, transmission (see microscopy, electron). (12 Dec 1998) |
| microscopy, fluorescence | 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 utilises antibodies that are labelled with fluorescent dye. (12 Dec 1998) |
| microscopy, immunoelectron | Microscopy in which the samples are first stained immunocytochemically and then examined using an electron microscope. Immunoelectron microscopy is used extensively in diagnostic virology as part of very sensitive immunoassays. (12 Dec 1998) |
| microscopy, interference | Microscopy in which physiological and photometric contrast in the image is influenced or produced by the action of optical components which regulate interference. (12 Dec 1998) |
| microscopy, phase-contrast | A form of interference microscopy in which variations of the refracting index in the object are converted into variations of intensity in the image. This is achieved by the action of a phase plate. (12 Dec 1998) |
| microscopy, polarization | Microscopy using polarised light in which phenomena due to the preferential orientation of optical properties with respect to the vibration plane of the polarised light are made visible and correlated parameters are made measurable. (12 Dec 1998) |
| microscopy, scanning tunneling | Electron microscopy in which a very sharp conducting needle is swept just a few angstroms above the surface of a sample. The tiny tunneling current that flows between the sample and the needle tip is measured and from this are produced three-dimensional topographs, with a lateral resolution often as good as 1-2 angstroms and a vertical resolution of less than 1 angstrom. Due to their composition, biological samples are usually coated with a conductive layer, e.g., by depositing a thin metal or carbon film on top of the sample, to enhance their conductivity. (12 Dec 1998) |
| microscopy, ultraviolet | Microscopy in which the image is formed by ultraviolet radiation and is displayed and recorded by means of photographic film. (12 Dec 1998) |