| NAA | N-acetyl aspartate; naphthaleneacetic acid; neutral amino acid; neutron activation analysis; neutrop... |
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| ND | Doctor of Naturopathy; nasal deformity; natural death; Naval Dispensary; neonatal death; neoplastic ... |
| NEP | negative expiratory pressure; nephrology; neutral endopeptidase; no evidence of pathology |
| neut | neuter, neutral; neutrophil |
| NF | nafcillin; National Formulary; nephritic factor; neurofibromatosis; neurofilament; neutral fraction;... |
| neutral | 1. Not engaged on either side; not taking part with or assisting either of two or more contending parties; neuter; indifferent. "The heart can not possibly remain neutral, but constantly takes part one way or the other." (Shaftesbury) 2. Neither good nor bad; of medium quality; middling; not decided or pronounced. "Some things good, and some things ill, do seem, And neutral some, in her fantastic eye." (Sir J. Davies) 3. <biology> Neuter. See Neuter. 4. <chemistry> Having neither acid nor basic properties; unable to turn red litmus blue or blue litmus red; said of certain salts or other compounds. Contrasted with acid, and alkaline. <chemistry> Neutral axis, Neutral surface, a salt formed by the complete replacement of the hydrogen in an acid or base; in the former case by a positive or basic, in the latter by a negative or acid, element or radical. Neutral tint, a bluish gray pigment, used in water colours, made by mixing indigo or other blue some warm colour. The shades vary greatly. Neutral vowel, the vowel element having an obscure and indefinite quality, such as is commonly taken by the vowel in many unaccented syllables. It is regarded by some as identical with the u in up, and is called also the natural vowel, as unformed by art and effort. Origin: L. Neutralis, fr. Neuter. See Neuter. Source: Websters Dictionary (01 Mar 1998) |
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| neutral axis of straight beam | The axis perpendicular to the plane of loading of a beam at stresses within the proportional limit; it lies at the gravity axis of the cross-section of the beam. (05 Mar 2000) |
| neutral beam injection | <radiobiology> This is one of the fundamental plasma heating methods. A particle accelerator is used to create fast ion beams (the particle energies are on the order of 100 keV), the ion beam is then passed through a neutral gas region, where the ions neutralise via charge-exchange reactions with the neutral gas. The neutralised beam is then injected into a magnetically confined plasma. The neutral atoms are unaffected (not confined) by the magnetic field, but ionize as they penetrate into the plasma. The high-energy ions then transfer some of their energy to the plasma particles in repeated collisions, and heat the plasma. (09 Oct 1997) |
| neutral buffered formalin fixative | A general histologic fixative less likely to leave formalin deposits in tissue than formol-saline fixative. (05 Mar 2000) |
| neutral-density filter | <equipment> A light-absorbing filter whose absorption spectrum is moderately flat. Depending on the type, the absorption curve is flat primarily in the visible spectral range, or may extend to varying degrees beyond the visible range. For video microscopy, this is an important point since the absorbance may or may not extend into the near-infrared region where the sensitivity of many video image pickup devices is very high. (05 Aug 1998) |
| neutral element | An element of the zero group of the periodic system comprising the rare gases, He, Ne, Ar, Kr, Xe, Rn. Synonym: noble element. (05 Mar 2000) |
| neutral fat | A triester of fatty acids and glycerol (i.e., triacylglycerol). (05 Mar 2000) |
| Streptomyces griseus neutral proteinase | <enzyme> Component of pronase; included in the group of microbial metalloproteinases EC 3.4.24.4 Chemical name: streptomyces griseus protease 3 Registry number: EC 3.4.24.- (26 Jun 1999) |
| neutral lipid storage disease | <syndrome> Congenital ichthyosis, leukocyte vacuoles, and variable involvement of other organ systems. Synonym: neutral lipid storage disease. (05 Mar 2000) |
| neutral mutation | A mutation that has no selective advantage or disadvantage. Considerable controversy surrounds the question of whether such mutations can exist. (18 Nov 1997) |
| neutral occlusion | An arrangement of teeth such that the maxillary and mandibular first permanent molars are in normal anteroposterior relation. Synonym: normal occlusion. Synonym: neutroclusion. (05 Mar 2000) |
| neutral oxide | An oxide that is neither an acid nor a base; e.g., water (hydrogen oxide, H2O). Synonym: indifferent oxide. (05 Mar 2000) |
| neutral point | The point at which a solution is neither acid nor alkaline (pH 7 at 22캜 for aqueous solutions). (05 Mar 2000) |
| neutral protease | <enzyme> Protease that is optimally active at neutral pH: See: proteases. (18 Nov 1997) |
| neutral reaction | PH of 7.00; H+ and OH- ion concentrations equal at 10-7 m at 22캜. Compare: dissociation constant of water. (05 Mar 2000) |