| rectified optics | <microscopy> Microscope lens system correcting the rotation of polarized light that takes place at high-incidence-angle interfaces between the polarizer and analyser. Rectification provides high extinction for polarized-light and Differential Interference Contrast microscopy at high numerical apertures, thus permitting bifringence or phase retardation combined with high in g low phase. (05 Aug 1998) |
|---|---|
| rectified spirit | <chemical> An organic chemical containing one or more hydroxyl groups. Alcohols can be liquids, semisolids or solids at room temperature. Common alcohols include ethanol (the type found in alcoholic beverages) methanol (found in methylated spirit and can cause blindness and other nervous system damage if ingested) and propanol. (06 May 1997) |
| rectified tar oil | A volatile oil distilled from pine tar; used externally in the treatment of skin diseases such as eczema and psoriasis. (05 Mar 2000) |
| polarizing element | <microscopy> A general term for a device for producing or analysing plane-polarized light. It may be a Nicol prism, some other form of calcite prism, a reflecting surface, or a polarizing filter. (05 Aug 1998) |
| polarizing power | <chemistry> Means that a charged species such as a proton can attract negatively charged electrons which causes a shift in the orbital. The higher the positive charge and the smaller the smaller the size, the greater the polarizing power of the species. (09 Jan 1998) |
| zone of polarizing activity | <cell biology> The small group of mesenchyme cells in avian limb buds that is located at the posterior margin of the developing bud and that produces a substance, possibly retinoic acid, that provides positional information to the developing limb bud. (18 Nov 1997) |
| 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, 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) |
| 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) |