| PBPK | physiologically based pharmacokinetic [model] |
|---|---|
| PDM | point distribution model |
| PRECEDE | predisposing, reinforcing, and enabling causes in educational diagnosis and evaluation [model] |
| PROC | GLM general linear model procedure |
| RA | radioactive; ragocyte; ragweed antigen; rapidly adapting [receptors]; reactive arthritis; reciprocal... |
| surface envelope model | <biology> A way of treating the hydrodynamics of a ciliary field by considering the whole surface of the ciliate to have an undulating surface. The undulations arise because of metachronism. (18 Nov 1997) |
|---|---|
| deterministic model | <epidemiology> A mathematical model in which the parameters and variables are not subject to random fluctuations, so that the system is at any time entirely defined by the initial conditions chosen. Contrast with a stochastic model. (05 Dec 1998) |
| discrete time model | <epidemiology> A model in which the system jumps from one state to the next at fixed intervals or timesteps. These difference models are simple to understand but often difficult to analyse; Contrast continuous time models. The parameters in such a model refer to the amount of change over the finite timestep; they are sometimes referred to as finite rates. In a (rather precise) sense, a differential equation is what you eventually get from a difference equation when you let the timestep get smaller and smaller and smaller. (05 Dec 1998) |
| induced fit model | A model to suggest a mode of action of enzymes in which the substrate binds to the active site of the protein, causing a conformational change in the protein. Synonym: Koshland-Nemethy-Filmer model. (05 Mar 2000) |
| transition probability model | A model to account for the apparently random variation in cell cycle time between individual animal tissue cells in culture that postulates that transition from G1 to s phase is probabilistic. Contrasts with hypotheses that require the accumulation of critical levels of particular proteins. (18 Nov 1997) |
| KNF model | <abbreviation> Koshland-Nemethy-Filmer model. (05 Mar 2000) |
| Koshland-Nemethy-Filmer model | <biochemistry, chemistry> A model to explain the allosteric form of cooperativity; in this model, in the absence of ligands, the protein exists in only one conformation; upon binding, the ligand induces a conformational change that may be transmitted to other subunits. Synonym: Adair-Koshland-Nemethy-Filmer model, induced fit model. (05 Mar 2000) |
| fluid bilayer model | Generally accepted model for membranes in cells. In its original form, the model held that proteins floated in a sea of phospholipids arranged as a bilayer with a central hydrophobic domain. Although it is now recognised that some proteins are restrained by interactions with cytoskeletal elements and that the phospholipid annulus around a protein may contain only specific types of lipid, the model is still considered broadly correct. (18 Nov 1997) |
| fluid mosaic model | A model used to conceptualise cell membranes, in it, the membranesare described as a structually and functionally asymmetric lipidbilayer studded with embedded proteins that aid in cross-membrane transport. (09 Oct 1997) |
| lock-and-key model | A model used to suggest the mode of operation of an enzyme in which the substrate fits into the active site of the protein like a key into a lock. (05 Mar 2000) |
| logistic model | A statistical model; in epidemiology, a model of risk as a function of exposure to a risk factor. (05 Mar 2000) |
| receptors, cytoplasmic and nuclear | Proteins in the cytoplasm or nucleus that specifically bind signalling molecules and trigger changes which influence the behaviour of cells. The major groups are the steroid hormone receptors, which usually are found in the cytoplasm, and the thyroid hormone receptors, which usually are found in the nucleus. Receptors, unlike enzymes, generally do not catalyze chemical changes in their ligands. (12 Dec 1998) |
| Remak's nuclear division | <cell biology> An unusual form of nuclear division, in which the nucleus simply constricts, rather like a cell without chromosome condensation or spindle formation. Partitioning of daughter chromosomes is haphazard. Observed in some Protozoa. (18 Nov 1997) |
| Pelger-Huet nuclear anomaly | Congenital inhibition of lobulation in the nuclei of neutrophilic leukocytes; most cells present band or bilobulate appearance, and only an occasional cell is trilobed; it is not associated with disease, but may be confused with leukocyte "shift to left"; autosomal dominant inheritance. (05 Mar 2000) |
| ribonucleoproteins, small nuclear | Highly conserved nuclear RNA-protein complexes that function in RNA processing in the nucleus, including pre-mRNA splicing and pre-mRNA 3'-end processing in the nucleoplasm. The u3 snrnp is localised in the nucleolus, where it aligns into base pairs with the 28s rrna precursor in a still unidentified region and functions in pre-rrna processing. The u7 snrnp aligns into base pairs with a conserved sequence in the 3'-end of histone pre-mRNA and is an essential cofactor for the cleavage that creates the mature nonadenylated 3'-end. (12 Dec 1998) |