| pulsatile flow | Rhythmic, intermittent propagation of a fluid through a vessel or piping system, in contrast to constant, smooth propagation, which produces laminar flow. The quality of blood flow, whether smooth (laminar) or pulsatile, is important to the integrity of the tissues being artificially perfused by various heart assist devices or in regional perfusion. (12 Dec 1998) |
|---|---|
| sheared flow | <radiobiology> Fluid flow where the magnitude of the fluid velocity changes along a direction perpedicular to the direction of the fluid flow. (Freeway traffic often exhibits sheared flow in that traffic in the fast lane moves more rapidly than traffic in the slow lane with the exits.) Sheared flow typically correlates with reduced transport and enhanced confinement. (This definition is rather informal and may not be fully technically correct - R.F. Heeter) (09 Oct 1997) |
| shear flow | A flow of a material in which parallel planes in the material are displaced in a direction parallel to each other. (05 Mar 2000) |
| shuttle flow | <cell biology> Bulk flow of the cytoplasm of cells. most conspicuous in large cells such as amoebae and the internodal cells of Chara where the rate of movement may be as high as 100 m/sec. See: cyclosis. (18 Nov 1997) |
| newtonian flow | The type of flow characteristic of a newtonian fluid. (05 Mar 2000) |
| Doppler colour flow | A computer-generated colour image produced by Doppler ultrasonography in which different directions of flow are represented by different hues. This technique is typically used to examine blood flow when evaluating heart disease. Where obstructions (for instance, arterial plaques) exist, blood flow will alter according to the principles of fluid mechanics. Eddies and reversals are readily apparent on the colour image. See: Doppler ultrasonography. (05 Mar 2000) |
| instream flow incremental methodology | Technique to predict the biomass of a fish species or life stage that a stream reach can support at a given flow, given knowledge of the fishes' physical habitat preferences. (09 Oct 1997) |
| isovolume pressure-flow curve | The relationship between transpulmonary pressure and respiratory air flow, expressed as a function of lung volume. (05 Mar 2000) |
| effective renal blood flow | The amount of blood flowing to the parts of the kidney that are involved with production of constituents of urine. (05 Mar 2000) |
| effective renal plasma flow | <physiology> The amount of plasma flowing to the parts of the kidney that have a function in the production of constituents of urine; the clearance of substances such as iodopyracet and p-aminohippuric acid, assuming that the extraction ratio in the peritubular capillaries is 100%. It is the amount of plasma perfusing the kidney tubules per unit time, generally measured by p-aminohippurate clearance. It should be differentiated from renal plasma flow which is approximately 10% greater than the effective renal plasma flow. (07 Mar 2000) |
| karyotyping, flow | Use of flow cytometry to analyze and/or separate chromosomes on the basis of their DNA content. Flow cytometry detects the light- absorbing or fluorescing properties of chromosomes passing in a narrow stream through a laser beam and with automated sorting devices can sort successive droplets of the stream into different fractions depending on the fluorescence emitted by each droplet. (12 Dec 1998) |
| flow | 1. To move with a continual change of place among the particles or parts, as a fluid; to change place or circulate, as a liquid; as, rivers flow from springs and lakes; tears flow from the eyes. 2. To become liquid; to melt. "The mountains flowed down at thy presence." (Is. Lxiv. 3) 3. To pproceed; to issue forth; as, wealth flows from industry and economy. "Those thousand decencies that daily flow From all her words and actions." (Milton) 4. To glide along smoothly, without harshness or asperties; as, a flowing period; flowing numbers; to sound smoothly to the ear; to be uttered easily. "Virgil is sweet and flowingin his hexameters." (Dryden) 5. To have or be in abundance; to abound; to full, so as to run or flow over; to be copious. "In that day . . . The hills shall flow with milk." (Joel III. 18) "The exhilaration of a night that needed not the influence of the flowing bowl." (Prof. Wilson) 6. To hang loose and waving; as, a flowing mantle; flowing locks. "The imperial purple flowing in his train." (A. Hamilton) 7. To rise, as the tide; opposed to ebb; as, the tide flows twice in twenty-four hours. "The river hath thrice flowed, no ebb between." (Shak) 8. To discharge blood in excess from the uterus. Origin: AS. Flowan; akin to D. Vloeijen, OHG. Flawen to wash, Icel. Floa to deluge, Gr. To float, sail, and prob. Ultimately to E. Float, fleet. 80. Cf. Flood. 1. A stream of water or other fluid; a current; as, a flow of water; a flow of blood. 2. A continuous movement of something abundant; as, a flow of words. 3. Any gentle, gradual movement or procedure of thought, diction, music, or the like, resembling the quiet, steady movement of a river; a stream. "The feast of reason and the flow of soul." (Pope) 4. The tidal setting in of the water from the ocean to the shore. See Ebb and flow, under Ebb. 5. A low-lying piece of watery land; called also flow moss and flow bog. Source: Websters Dictionary (01 Mar 1998) |
| flow cytoenzymology | A technique for for separating and sorting cells based on the presence ofspecific enzymes that create acoloured material when they bind to a substrate. (09 Oct 1997) |
| flow cytometry | <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) |
| flow cytophotometry | <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) |