pale-staining zone
| 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) |
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| 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) |
| neutral red | <chemical> 3-amino-7-dimethylamino-2-methylphenazine hydrochloride. A vital dye used as an indicator and biological stain. Various adverse effects have been observed in biological systems. Pharmacological action: dyes, indicators and reagents. Chemical name: 2,8-Phenazinediamine, N8,N8,3-trimethyl-, monohydrochloride (12 Dec 1998) |
| neutral spirits | Spirits distilled from suitable raw materials, are 95% ethanol (v/v) that is, at least 190 proof when distilled. Used for blending with straight whiskey and for making gin, cordials, liqueurs, and vodka. See: alcohol. Proof spirit, dilute alcohol, specific gravity 0.920, containing 49.5% by weight (57.27% by volume) of C2H5OH at 15.56캜. Originally in Great Britain it was the weakest alcohol that would permit ignition of gunpowder moistened with it. British proof spirit has a specific gravity of 0.9198 and contains 49.2% C2H5OH by weight, or 57.1% by volume at the temperature of 10.56캜. (05 Mar 2000) |