| STM | scanning tunneling microscope; short-term memory; streptomycin |
|---|---|
| CEM | computerized electroencephalographic map; conventional transmission electron microscope |
| TEM | transmission electron microscope/ microscopy; triethylenemelamine |
| UEM | universal electron microscope |
| SEM | sample evaluation method; scanning electron microscopy; secondary enrichment medium; standard error ... |
| scanning speech | Measured or metered, often slow speech. (05 Mar 2000) |
|---|---|
| scanning tunnelling microscopy | <procedure> A form of ultra high resolution microscopy of a surface in which a very small current is passed through a surface and is detected by a microprobe of atomic dimnensions at its tip that scans the surface by use of a piezodrive. In the simplest form the current transferred to the probe is recorded as an indication of the contours of molecules on the surface above the local plane. In more complex forms feedback is used to hold the probe at a constant difference and the signal in the feedback loop indicates the contours of the molecule. Capable of resolving single atoms and known to work for nonconducting molecules as well as conducting ones. (18 Nov 1997) |
| linker scanning | A type of deletion mutagenesis where the distance and/or reading frame between potentially important regions is maintained by replacement with a synthetic oligonucleotide of known sequence. (05 Mar 2000) |
| binocular microscope | <instrument, microscopy> A microscope fitted with double eyepieces for vision with both eyes. The purpose in dividing the same image from a single objective of the usual compound micro-scope is to reduce eyestrain and muscular fatigue which may result from monocular, high-power microscopy. The purpose in obtaining a different image for each of two oculars is to provide stereoscopy by means of two different angles of view. There are two kinds of stereoscopic microscopes: binobjective (Greenough) older type and monobjective (common main objective) newer type. (See stereo microscope, Greenough microscope, etc.) (05 Aug 1998) |
| Rheinberg microscope | <instrument> A modified form of dark-field microscope in which the central opaque stop in the condenser is replaced by a coloured filter, producing a background of contrasting colour against which the specimen is illuminated. (05 Mar 2000) |
| Greenough microscope | <instrument, microscopy> One of two kinds of stereomicroscopes with two separate compound microscopes, one for each eye, focused on the same object. The other kind has a common main objective. See: binocular microscope. (05 Aug 1998) |
| phase-contrast microscope | <instrument> A specially constructed microscope that has a special condenser and objective containing a phase-shifting ring whereby small differences in index of refraction are made visible as intensity or contrast differences in the image; particularly useful for examining structural details in transparent specimens such as living or unstained cells and tissues. (05 Mar 2000) |
| microscope | <instrument> A piece of laboratory equipment that is used to magnify small things that are too small to be seen by the naked eye, or too small for the details to be seen by the naked eye, so that their finer details can be seen and studied. Examples are the light (or optical) microscope, electron microscope, X-ray microscope, and acoustic microscope. (09 Oct 1997) |
| microscope, compound | A microscope that consists of two microscopes in series, the first serving as the ocular lens (close to the eye) and the second serving as the objective lens (close to the object to be viewed). Credit for creating the compound microscope goes usually to the dutch spectaclemakers hans and zacharias janssen who in 1590 invented an instrument that could be used as either a microscope or telescope. The compound microscope evolved into the dominant type of optical microscope today. (12 Dec 1998) |
| microscope, field emission | <microscopy> An image-forming device in which a strong electrostatic field causes cold emission of electrons from a sharply rounded point or from a specimen that has been placed on that point. The electrons are accelerated to a phosphorescent screen, or photographic film, giving a visible picture of the variation of emission over the specimen surface. (05 Aug 1998) |
| microscope, fluorescent | A microscope equipped to examine material that fluoresces under ultraviolet (uv) light. (12 Dec 1998) |
| microscope, Greenough | <microscopy> A stereoscopic microscope with paired objectives, prisms, and eyepieces invented by H. Greenough. The name is sometimes incorrectly used for any stereoscopic microscope with paired objectives showing erect images. (05 Aug 1998) |
| microscope mirror | <microscopy> Usually plane on one side and concave on the other. The flat side is generally used unless the objective is of very low power and there is no condenser. The mirror should be so mounted that the concave side can be focused on the specimen. (05 Aug 1998) |
| microscope, simple | <microscopy> A microscope that has a single converging lens (or a combination of lenses that function optically as a single converging lens). Anton van leeuwenhoek (1632-1723) made good use of the simple microscope to look at the life within a drop of water, and such. The magnifying properties of lenses had been well known in ancient times (for example to the greeks and romans) but it was not until about 1600 that it became possible to make small lenses with the precision needed to make a microscope. (12 Dec 1998) |
| microscope, stereoscopic | <microscopy> Either one of two kinds: binocular-bi-nobjective, such as the Greenough microscope type, and binocular microscope with common main objective. See: stereomicroscope. (05 Aug 1998) |