| APDI | Adult Personal Data Inventory |
|---|---|
| APIP | additional personal injury protection |
| DPI | daily permissible intake; days post inoculation; dietary protein intake; diphtheria-pertussis immuni... |
| EPAQ | Extended Personal Attitudes Questionnaire |
| EPPS | Edwards Personal Preference Schedule |
| PC | Personal Computer |
|---|---|
| PDA | Personal Digital Assistant |
| POI | Personal Orientation Inventory |
| PPE | Personal protective equipment |
| Rayleigh equation | A ratio of red to green required by each observer to match spectral yellow. Synonym: Rayleigh test. (05 Mar 2000) |
|---|---|
| Gibbs-Helmholtz equation | An equation expressing the relationship in a galvanic cell between the chemical energy transformed and the maximal electromotive force obtainable. (05 Mar 2000) |
| Victor-Michaelis-Menten equation | <chemistry> Equation derived from a simple kinetic model for a single-substrate non-cooperative enzyme-catalyzed reaction that successfully accounts for the hyperbolic adsorption isotherm) relationship between substrate concentration and reaction rate. V = Vmax x S/(S + Km), where V is the initial velocity of the reaction, Km is the Michaelis constant, Vmax is the maximum rate approached by very high substrate concentrations and S is the initial substrate concentration. Similar equations can be derived for conditions in which the product is present and for multisubstrate enzymes. Synonym: Victor-Michaelis-Menten equation. (12 Jul 2000) |
| Goldman equation | An equation derived to predict membrane potentials in terms of the membrane's permeability to ions and their concentrations on either side. Synonym: constant field equation, Goldman-Hodgkin-Katz equation, GHK equation. (05 Mar 2000) |
| Goldman-Hodgkin-Katz equation | An equation derived to predict membrane potentials in terms of the membrane's permeability to ions and their concentrations on either side. Synonym: constant field equation, Goldman-Hodgkin-Katz equation, GHK equation. (05 Mar 2000) |
| grad-shafranov equation | <radiobiology> Reduced magnetohydrodynamic-equilibrium equation for an axisymmetric, toroidal plasma. (Similar reduced equations can be derived for the cases of helical symmetry and for the straight cylinder.) Analytic and numerical studies of these equations are important in exploring potential plasma configurations. The lowest order force balance in the plasma is simply that the Lorentz force must be balanced by the pressure force. This balance, combined with Maxwell's equations, determines the equilibrium configuration of the magnetic field. When the toroidal configuration is axisymmetric, and the equilibrium plasma flow is zero, the magnetic field may be written in terms of a stream function \psi that satisfies the Grad-Shafranov equation \Delta\psi = - \mu_0 R^2 p'(\psi) - FF'(\psi). Here p is the plasma pressure and f = R B_\phi. (R is the radial distance from the axis of the machine). In an axisymmetric torus, in the absence of equilibrium plasma fluid flows, the magnetic field may be written in terms of a scalar potential. When the plasma is in equilibrium (forces balance and the plasma is stationary), this scalar potential obeys a non-linear elliptic equation known as the Grad-Shafranov equation. (09 Oct 1997) |
| chemical equation | A representation of a chemical reaction in which chemical symbols represent reactants on the left side and products on the right side. (09 Oct 1997) |
| Michaelis-Menten equation | <chemistry> Equation derived from a simple kinetic model for a single-substrate non-cooperative enzyme-catalyzed reaction that successfully accounts for the hyperbolic adsorption isotherm) relationship between substrate concentration and reaction rate. V = Vmax x S/(S + Km), where V is the initial velocity of the reaction, Km is the Michaelis constant, Vmax is the maximum rate approached by very high substrate concentrations and S is the initial substrate concentration. Similar equations can be derived for conditions in which the product is present and for multisubstrate enzymes. Synonym: Victor-Michaelis-Menten equation. (12 Jul 2000) |
| constant field equation | An equation derived to predict membrane potentials in terms of the membrane's permeability to ions and their concentrations on either side. Synonym: constant field equation, Goldman-Hodgkin-Katz equation, GHK equation. (05 Mar 2000) |
| Henderson-Hasselbalch equation | <chemistry> The Henderson-Hasselbalch equation is the equation: PH = pK + log ([A-]/[HA]) Where pH is the acidity or alkalinity of the buffer solution, pK is the negative logarithm of the equilibrium constant (Kd) for the ionisation of the acid form (A-) of the compound used to buffer the solution for the reaction HA = H+ +A-, [A-] is the molar concentration of the ionised form of the buffer compound, and [HA] is the molar concentration of the nonionised form of the buffer compound. (09 Oct 1997) |
| Hill's equation | The equation,y(1-y) = [S]n/Kd, where y is the fractional degree of saturation, [S] is the binding ligand concentration, n is the Hill coefficient, and Kd is the dissociation constant for the ligand. The Hill coefficient is a measure of the cooperativity of the protein; the larger the value, the higher the cooperativity. This coefficient cannot be higher than the number of binding sites. For the oxygen binding curve of haemoglobin, an association constant, Ka, is used and the equation becomes y/(1-y) = Ka[S]n. For human blood, n equals 2.5. Compare: Hill plot. (05 Mar 2000) |
| Hufner's equation | <physiology> An equation expressing the relationship between myoglobin dissociation and oxygen partial pressure: ([MBO2]/[Mb]) = (K x pO2). (05 Mar 2000) |
| Nernst equation | <physics> A basic equation of biophysics that describes the relationship between the equilibrium potential difference across a semipermeable membrane and the equilibrium distribution of the ionic permeant species. It is described by: E = (RT/zF).ln[C1/C2 Where E is the potential on side 2 relative to side 1 in volts), R is the gas constant (8.314 J Kexp 1 molexp 1), T is the absolute temperature, z is the charge on the permeant ion, f is the Faraday constant (96500 C molexp 1) and C1 and C2 are the concentrations (more correctly activities) of the ions on sides 1 and 2 of the membrane. It can be seen that this equation is a solution of the more general equation of electrochemical potential, for the special case of equilibrium. The equation described the voltage generated by ion selective electrodes, like the laboratory pH electrode and approximates the behaviour of the resting plasma membrane (see resting potential). (13 Nov 1997) |
| Nernst's equation | The equation relating the equilibrium potential of electrodes to ion concentrations; the equation relating the electrical potential and concentration gradient of an ion across a permeable membrane at equilibrium: E = [RT / nF Origin: Ln (C1/C 2)], where E = potential, R = absolute gas constant, T = absolute temperature, n = valence, F = the Faraday, ln = the natural logarithm, and C1 and C2 are the ion concentrations on the two sides; in nonideal solutions, concentration should be replaced by activity. See: Nernst's theory, activity. (05 Mar 2000) |
| Svedberg equation | See: sedimentation constant. (05 Mar 2000) |