| nonlamellar bone | Bony tissue characteristic of the embryonal skeleton, in which the collagen fibres of the matrix are arranged irregularly in the form of interlacing networks. Synonym: nonlamellar bone, reticulated bone. (05 Mar 2000) |
|---|---|
| nonlinear dynamics | The study of systems which respond disproportionately (nonlinearly) to initial conditions or perturbing stimuli. Nonlinear systems may exhibit chaos which is classically characterised as sensitive dependence on initial conditions. Chaotic systems, while distinguished from more ordered periodic systems, are not random. When their behaviour over time is appropriately displayed (in phase space), constraints are evident which are described by strange attractors. Phase space representations of chaotic systems, or strange attractors, usually reveal fractal (fractals) self-similarity across time scales. Natural, including biological, systems often display nonlinear dynamics and chaos. (12 Dec 1998) |
| nonlipid histiocytosis | histiocytosis |
| nonlipid reticuloendotheliosis | <haematology> An immunologic disorder of unknown cause where there is proliferation of histiocytes (a type of cell in the immune system) in the bloodstream. The disorder is characterised by inflammation of the bronchioles and small pulmonary vessels that leads to fibrosis and destruction of alveolar cell walls. Cigarette smoking is considered a risk factor. Individuals with this disorder are also at increased risk for spontaneous pneumothorax. Symptoms include cough, chest pains, shortness of breath, fever, weight loss and malaise. Bronchoscopy with biopsy confirms the diagnosis. Childhood forms exist and cause more systemic symptoms and findings such as failure to thrive, weight loss, fevers, irritability, rash and bone pains. Treatment is with corticosteroids. (27 Sep 1997) |
| nonmaleficence | The ethical principle of doing no harm, based on the Hippocratic maxim, primum non nocere, first do no harm. Origin: non-+ L. Maleficencia, evildoing, fr. Male, badly, wrongly, + facio, to do, act (05 Mar 2000) |
| nonmalignant | <oncology> Not malignant, as a disease. Source: Websters Dictionary (01 Mar 1998) |
| nonmedullated | <anatomy> Not medullated; without a medulla or marrow, or without a medullary sheath; as, a nonmedullated nerve fibre. Source: Websters Dictionary (01 Mar 1998) |
| nonmedullated fibres | A fibre having no myelin covering (CNS); a naked axon; in the PNS represented by all axons lying in troughs in a single Schwann cell (Schwann cell unit); a slow conducting fibre. Synonym: gray fibres, nonmedullated fibres, Remak's fibres. (05 Mar 2000) |
| nonmelanoma skin cancer | <oncology> Skin cancer that does not involve melanocytes. Basal cell cancer and squamous cell cancer are nonmelanoma skin cancers. (12 Dec 1998) |
| nonMendelian inheritance | <genetics> In eukaryotes, patterns of gene transmission not explicable in terms of segregation, independent assortment and linkage. May be due to cytoplasmic inheritance, gene conversion, meiotic drive, etc. (18 Nov 1997) |
| nonmetal | <chemistry> Any one of the set of elements which, as contrasted with the metals, possess, produce, or receive, acid rather than basic properties; a metalloid; as, oxygen, sulphur, and chlorine are nonmetals. Source: Websters Dictionary (01 Mar 1998) |
| nonmetallic | 1. Not metallic. 2. <chemistry> Resembling, or possessing the properties of, a nonmetal or metalloid; as, sulphur is a nonmetallic element. Source: Websters Dictionary (01 Mar 1998) |
| nonmotile leukocyte | <haematology> A term sometimes used with reference to lymphocytes, monocytes, and plasma cells; although such forms actually have some degree of motility, they are nonmotile in comparison with the actively ameboid, neutrophilic, basophilic, and eosinophilic leukocyte's. (05 Mar 2000) |
| nonmyelinated | Denoting nerve fibres (axons) lacking a myelin sheath. Synonym: amyelinated, amyelinic, nonmedullated, nonmyelinated, unmedullated. (05 Mar 2000) |
| nonneoplastic | <oncology> Not neoplastic. (05 Mar 2000) |