| AnEx, an ex | anodal excitation |
|---|---|
| DANTE | delays altered with nutation for tailored excitation |
| EC | effective concentration; ejection click; electrochemical; electron capture; embryonal carcinoma; eme... |
| EJP | excitation junction potential |
| GE | gastric empyting; gastroemotional; gastroenteritis; gastroenterology; gastroenterostomy; gastroesoph... |
| excitation contraction coupling | <physiology> Name given to the chain of processes coupling excitation of a muscle by the arrival of a nervous impulse at the motor end plate to the contraction of the filaments of the sarcomere. The crucial link is the release of calcium from the sarcoplasmic reticulum and the analogy is often drawn between this and stimulus secretion coupling, that also involves calcium release into the cytoplasm. (18 Nov 1997) |
|---|---|
| excitation radiation | <radiobiology> Line radiation (at characteristic frequencies / wavelengths) as a result of the promotion of electrons or other constituent particles of a larger system to excited states, and the subsequent de-excitation of these states by radiative transitions. (09 Oct 1997) |
| excitation spectrum | Fluorescence produced over a range of wavelengths of the exciting light. (05 Mar 2000) |
| excitation wave | A wave of altered electrical conditions that is propagated along a muscle fibre preparatory to its contraction. (05 Mar 2000) |
| law of excitation | A motor nerve responds, not to the absolute value, but to the alteration of value from moment to moment, of the electric current; i.e., rate of change of intensity of the current is a factor in determining its effectiveness. Synonym: Du Bois-Reymond's law. (05 Mar 2000) |
| law of polar excitation | A given segment of a nerve is irritated by the development of catelectrotonus and the disappearance of anelectrotonus, but the reverse does not hold; i.e., excitation occurs at the cathode when the circuit is closed and at the anode when it is opened. Synonym: Pfluger's law. (05 Mar 2000) |
| ratio imaging fluorescence microscopy | <procedure> A method of measurement of intracellular pH or intracellular calcium levels, using a fluorescent probe molecule (see fura-2), in which the two different excitation wavelengths are used and the emitted light levels compared. If emission at one wavelength is sensitive to the intracellular ion level and emission at the other wavelength is not, then standardisation for intracellular probe concentration, efficiency of light collection, inactivation of probe and thickness of cytoplasm can all be performed automatically. (17 Dec 1997) |
| microscopy, fluorescence | Microscopy of specimens stained with fluorescent dye (usually fluorescein isothiocyanate) or of naturally fluorescent materials, which emit light when exposed to ultraviolet or blue light. Immunofluorescence microscopy utilises antibodies that are labelled with fluorescent dye. (12 Dec 1998) |
| spectrometry, fluorescence | Measurement of the intensity and quality of fluorescence. (12 Dec 1998) |
| Eranko's fluorescence stain | <technique> Exposure of frozen sections to formaldehyde which produces a strong yellow-green fluorescence from cells containing norepinephrine. (05 Mar 2000) |
| fluorescence | <chemistry, physics> The emission of one or more photons by a molecule or atom activated by the absorption of a quantum of electro magnetic radiation. Typically the emission, that is of longer wavelength than the excitatory radiation, occurs within 10exp 8 seconds: phosphorescence is a phenomenon with a longer or much longer delay in re radiation. Note that rays, X-rays, UV, visible light and IR radiations may all stimulate fluorescence. (25 Jun 1999) |
| fluorescence-activated cell sorter | <technique> Flow cytometry is an emerging technique which holds great promise for the separation, classification and quantitation of blood cells and antibodies which affect blood cells. Complex computerised instruments are used to pass a monocellular stream of cells, platelets or other microscopic particulate elements through a beam of laser light. The cells are categorised first by size and then computer analysed to sort the mixture of cellular elements into cell type by size. Cells are labelled with fluorescent dye and then passed, in suspending medium, through a narrow dropping nozzle so that each cell is in a small droplet. A laser based detector system is used to excite fluorescence and droplets with positively fluorescent cells are given an electric charge. Charged and uncharged droplets are separated as they fall between charged plates and so collect in different tubes. The machine can be used either as an analytical tool, counting the number of labelled cells in a population or to separate the cells for subsequent growth of the selected population. Further sophistication can be built into the system by using a second laser system at right angles to the first to look at a second fluorescent label or to gauge cell size on the basis of light scatter. The great strength of the system is that it looks at large numbers of individual cells and makes possible the separation of populations with, for example: particular surface properties. Tabulation of counted data in conjunction with size analysis enables determination of relative percentages of each specific cellular subset for which monoclonal antibody conjugates are utilised, even when the size of the cell is identical to other subset species. Flow cytometry is a slightly imprecise but common term for the use of the Fluorescence-activated Cell Sorter (FACS). (01 Dec 1998) |
| fluorescence-activated cell sorting | <technique> A technique for separating and sorting cells marked with a fluorescent label based on how much they fluoresce at a particular wavelength. (12 Jan 1998) |
| fluorescence in situ hybridization | <molecular biology, technique> A type of in situ hybridization in which target sequences are stained with fluorescent dye so their location and size can be determined using fluorescence microscopy. This staining is sufficiently distinct that the hybridization signal can be seen both in metaphase spreads and in interphase nuclei. Acronym: FISH (25 Jun 1999) |
| fluorescence microscope | <instrument, microscopy> A microscope illuminated by ultraviolet or blue light so that the object may re-radiate light of longer wavelengths. To protect the eyes, a W-absorbing filter should be provided if not built into the fluorescence microscope. (05 Aug 1998) |