| MRS | magnetic resonance spectroscopy; Mania Rating Scale; medical receiving station; Melkersson-Rosenthal... |
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| MRSI | magnetic resonance spectroscopy imaging |
| MRT | magnetic resonance tomography; maximum relaxation time; median range score; median reaction time; me... |
| NMR | neonatal mortality rate; nictitating membrane response; nuclear magnetic resonance |
| NMRI | Naval Medical Research Institute; nuclear magnetic resonance imaging |
| cracked-pot resonance | A peculiar sound, resembling that heard on striking a cracked pot, elicited on percussing over a pulmonary cavity that commmunicates with a bronchial tube, when the patient's mouth is open. Synonym: cracked-pot sound. (05 Mar 2000) |
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| cyclotron resonance | <radiobiology> Charged particles in a magnetic field resonate with (and absorb energy from) an electric field (perpendicular to the magnetic field) which oscillates at the particles' cyclotron frequency, or at a harmonic (multiple) of that frequency. (09 Oct 1997) |
| hybrid resonance | <radiobiology> A resonance in a magnetised plasma which involves aspects of both bunching of lighter species parallel to the magnetic field, characterised by the plasma frequency, and perpendicular particle motions (heavier species) characterised by the cyclotron frequency. (09 Oct 1997) |
| hydatid resonance | A peculiar vibratile resonance heard on auscultatory percussion over a hydatid cyst. (05 Mar 2000) |
| skodaic resonance | A peculiar, high-pitched sound, less musical than that obtained over a cavity, elicited by percussion just above the level of a pleuritic effusion. Synonym: Skoda's sign, Skoda's tympany. (05 Mar 2000) |
| surface plasmon resonance | <chemistry> Alteration in light reflectance as a result of binding of molecules to a surface from which total internal reflection is occuring. Used in the Biacore (Pharmacia Trademark) machine that detects the binding of ligand to surface immobilised receptor or antibody. (19 Jan 1998) |
| tympanitic resonance | 1. <clinical sign> A flatulent distention of the belly; tympanites. 2. Hence, inflation; conceit; bombast; turgidness. "Thine 's a tympany of sense." "A plethoric a tautologic tympany of sentence." (De Quincey) Origin: Gr, fr. A kettledrum. See Tympanites. (28 Oct 1998) |
| aperture for electron microscopy | <technique> Anode aperture: The opening in the accelerating voltage anode shield of the electron gun through which the electrons must pass to irradiate the specimen. Condenser aperture: An opening in the condenser lens controlling the number of electrons entering the lens and the angular aperture of the electron beam. The angular aperture can also be controlled by the condenser lens current. Physical objective aperture: A metallic diaphragm, with a small central hole, used to limit the cone of electrons accepted by the objective lens. This improves image-contrast since highly scattered electrons are prevented from arriving at the Gaussian image plane and therefore cannot contribute to background fog. Aplanatic. Free from spherical aberration and coma. (05 Aug 1998) |
| Auger electron | An electron ejected from a lower energy orbital after a photoelectric interaction of an X-ray photon with a K-shell electron by the characteristic radiation photon; the Auger electron recoils with energy equal to the characteristic radiation less the difference in shell binding energies. See: photoelectric effect. (05 Mar 2000) |
| backscattered electron | <microscopy> Produced by an incident electron colliding with the nucleus of an atom in the specimen. The incident electron is then scattered backward about 180 degrees with no appreciable loss of energy, an elastic collision. (05 Aug 1998) |
| backscattered electron imaging | <microscopy> The production of backscattered electrons from a sample varies directly with the specimen's average atomic number, higher atomic number elements produce more backscattered electrons than lower atomic number ones. Detection of Backscattered Electrons is achieved by using a donut shaped solid state saemiconductor device mounted on the bottom of the objective lens. When Backscattered Electrons strike the detector electron-hole pairs are created which are then counted. This quantity is translated into a pixel intensity and displayed on the CRT, forming the image. By splitting the detector into halves (or quadrants) differences in the signal level on the individual detector segments provide surface topography information. (05 Aug 1998) |
| valence electron | One of the electron's that take part in chemical reactions of an atom. (05 Mar 2000) |
| Parallel Electron Energy Loss Spectroscopy | <technique> Electron energy loss spectroscopy analyses the inelastically scattered electrons present in the beam after it has been transmitted through the sample. An electron energy loss spectrum typically consists of a monatomic decreasing background on which are superimposed a number of peaks. Each peak is characteristic of the scattering process that has occurred in the sample. The peaks can be used to obtain information about the chemical composition and electronic structure of the sample. Electron energy loss spectra are acquired typically in a magnetic sector spectrometer located under the camera chamber of the transmission electron microscope. Spatial resolution is typically limited by the minimum probe diameter of the microscope. Electron energy loss spectroscopy tends to be complimentary to EDS in that it can be used to analyse very thin samples of low Z materials. Acronym: PEELS (05 Aug 1998) |
| reverse electron transport | <chemistry> The energy-dependent movement of electrons against the thermodynamic gradient to form a strong reductant from a weaker electron donor. (11 Jan 1998) |
| microscope, electron | <microscopy> An electron-optical device which produces a magnified image of an object. Detail may be revealed by virtue of selective transmission, reflection, or emission of electrons by the object. (05 Aug 1998) |