| CTEM | conventional transmission electron microscopy |
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| e | base of natural logarithms, approximately 2.7182818285; egg transfer; ejection; electric charge; ele... |
| e- | negative electron |
| EB | elective abortion; electron beam; elementary body; emotional behavior; endometrial biopsy; epidermol... |
| EBCT | electron-beam computed tomography |
| positive transference | Transference characterised by predominantly friendly, respectful, and positive feelings on the part of the patient toward the analyst. (05 Mar 2000) |
|---|---|
| intermittent positive-pressure breathing | Application of positive pressure to the inspiratory phase of spontaneous respiration. See: controlled mechanical ventilation (12 Dec 1998) |
| intermittent positive-pressure ventilation | Application of positive pressure to the inspiratory phase when the patient has an artificial airway in place and is connected to a ventilator. See: controlled mechanical ventilation (12 Dec 1998) |
| t-lymphocytopenia, idiopathic CD4-positive | Reproducible depletion of CD4+ lymphocytes below 300 per cubic millimeter in the absence of HIV infection or other known causes of immunodeficiency. This is a rare, heterogeneous syndrome and does not appear to be caused by a transmissible agent. (12 Dec 1998) |
| eyepiece, positive | <microscopy> An eyepiece in which the real image of the object is formed below the lower lens element, of the eyepiece. (05 Aug 1998) |
| false positive | <statistics> A test result that is read as positive when it is really negative. (27 Sep 1997) |
| false-positive reaction | <statistics> An erroneous or mistakenly positive response. Positive test results in subjects who do not possess the attribute for which the test is conducted. The labeling of healthy persons as diseased when screening in the detection of disease. (05 Mar 2000) |
| leukaemia, calla-positive | Acute leukaemia in which lymphocytes are positive for the common acute lymphoblastic leukaemia antigen (calla). (12 Dec 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) |