| immune thrombocytopenia | Thrombocytopenia associated with antiplatelet antibodies. See: isoimmune neonatal thrombocytopenia, autoimmune neonatal thrombocytopenia. (05 Mar 2000) |
|---|---|
| immune thrombocytopenic purpura | <haematology> A low number of platelets in the blood, which is common in people with HIV, but often resolves as immune deficiency worsens. HIV-related ITP usually does not have serious consequences. Its cause has not been definitely determined. Treatment with AZT frequently alleviates the condition. (09 Oct 1997) |
| immune tolerance | The specific failure of a normally responsive individual to make an immune response to a known antigen. It results from previous contact with the antigen by an immunologically immature individual (foetus or neonate) or by an adult exposed to extreme high-dose or low-dose antigen, or by exposure to radiation, antimetabolites, antilymphocytic serum, etc. (12 Dec 1998) |
| tetanus immune globulin | <protein> A protein antibody to tetanus toxin, given as passive immunity for those lacking any prior tetanus vaccination. (27 Sep 1997) |
| zoster immune globulin | A globulin fraction of pooled plasma from individuals who have recovered from herpes zoster; used prophylactically and therapeutically for varicella. (05 Mar 2000) |
| 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) |
| Convergent Beam Electron Diffraction | <microscopy> An electron probe is tightly focused on a transmission electron microscopy specimen and the resulting pattern of diffracted electrons is observed. The patterns contains information on the crystal symmetry and atomic and electronic structure of the sample. Regions as small as 0.2 nm may be examined. Acronym: CBED (05 Aug 1998) |
| conversion electron | An internal conversion electron. (05 Mar 2000) |
| positive electron | A subatomic particle of mass and charge equal to the electron but of opposite (i.e., positive) charge. Synonym: positive electron. (05 Mar 2000) |