| AES | acetone-extracted serum; American Electroencephalographic Society; American Encephalographic Society... |
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| ATEM | analytic transmission electron microscopy |
| BEI | back-scattered electron imaging; biological exposure indexes; butanol-extractable iodine |
| BeV, Bev | billion electron volts |
| CEM | computerized electroencephalographic map; conventional transmission electron microscope |
| transfer factor | A dialysable factor obtained from sensitised T-cells by freezing and thawing, that may possibly immunopotentiate animals.The transfer of specific immunity from one animal to another has been claimed. (18 Nov 1997) |
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| transfer genes | Gene's carried by a conjugative plasmid, essential for fertility and establishment of the bacterial donor state. (05 Mar 2000) |
| transfer imaging | The production of an ultrasound image by detection and analysis of sound on the opposite side of the body from the emitting transducer. Synonym: through transfer imaging. (05 Mar 2000) |
| transfer (psychology) | Change in learning in one situation due to prior learning in another situation. The transfer can be positive (with second learning improved by first) or negative (where the reverse holds). (12 Dec 1998) |
| transfer RNA | <molecular biology> A nucleic acid found in all living cells. Plays a role in transferring information from DNA to the protein-forming system of the cell. (16 Dec 1997) |
| energy transfer | The transfer of energy of a given form among different scales of motion. In biochemistry, this concept generally refers to the transfer of groups from compounds that contain energy-rich bonding arrangements to compounds that have relatively energy-poor bonding characteristics via thermodynamically permissible enzymatic reactions. This principle is a major premise of the interaction between energy-producing and energy-utilizing metabolic pathways in living cells. (12 Dec 1998) |
| zygote intra-fallopian transfer | <gynaecology> In vitro fertilization with a transfer of the zygote into the fallopian tube, a combination of in vitro fertilization and gamete intra-fallopian transfer. An assisted reproduction technique consisting of hormonal stimulation of the ovaries, laparoscopic follicular aspiration of oocytes, in-vitro fertilization, and intra-fallopian transfer of the zygote by transabdominal cannulation at the pronuclear stage (before cleavage). Acronym: ZIFT (12 Dec 1998) |
| fluorescence energy transfer | <technique> Transfer of energy from one fluorochrome to another. The emission wavelength of the fluorochrome excited by the incident light must approximately match the excitation wavelength of the second fluorochrome. If light at the second emission wavelength is detected, it implies that the two fluorochromes were physically within a few nanometres. Used as a technique to probe protein or cell interactions. (25 Jun 1999) |
| Fourier transfer | A mathematical technique to express a time-varying function or signal into components at different frequencies, giving the phase and amplitude of each; used in computed tomography and magnetic resonance image reconstruction transformation. (05 Mar 2000) |
| linear energy transfer | <radiobiology> Average amount of energy lost per unit of particle track length and expressed in keV um-1. Acronym: LET (16 Dec 1997) |
| 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) |