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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Theoretical chemistry accounts 69 (1986), S. 71-81 
    ISSN: 1432-2234
    Keywords: Electron density ; Gaussian models ; Point charge models ; Water molecule
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The electron density of the water molecule, as calculated by a standard program, is approximated by linear combinations of spherical Gaussians. The accuracy of the result is studied as a function of the numbers and positions of the Gaussians. Since this shows where the charge is located in the molecule it has immediate physical significance. The building-up of the density can be followed in more and more detail. From these expansions, point charge models of water are readily deduced. These are compared with models of similar kinds used by other authors. Some of the calculations have been repeated with a wavefunction of higher accuracy to investigate the stability of the results. Results show that the more accurate density requires more Gaussians to represent its greater complexity.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Theoretical chemistry accounts 69 (1986), S. 425-436 
    ISSN: 1432-2234
    Keywords: Molecular electrostatic potential ; Gaussian models ; Point charge models ; Water molecule
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The calculation of the molecular electrostatic potential from simplified models of the electron density is considered. Results are shown for water, hydrogen fluoride and ammonia. Little loss of accuracy is evident when the density is represented by a linear sum of well-chosen Gaussians. When these are further simplified into sets of point charges the inner parts of the molecule are poorly represented. More elaborate point moments make the representation worse. On the other hand a mixed representation with point charges and one diffuse Gaussian gives all the essential features of the potential of these molecules.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Clinical Anatomy 3 (1990), S. 307-316 
    ISSN: 0897-3806
    Keywords: human nasal mucosa ; mast cell sub-types ; Life and Medical Sciences ; Miscellaneous Medical
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The light microscopic features of the mucous membrane of intact inferior nasal concha are described. A proposal is made to standardize the terminology of tissue deep to the basement membrane as superficial or deep tunica propria. The range of epithelia found and the distribution of the various cell types and fibers present in the conchae are described. The variability of the tissue is stressed, both at gross and cellular levels. Mast cells are stained by using an Alcian blue and safranin technique in which the critical electrolyte concentration is adjusted to 0.3M MgCl2 This demonstrates two sub-types of mast cell. One is a relatively small, pale staining, spindle-shaped, superficially located cell, containing turquoise granules, while the other is generally more deeply located, larger, round or ovoid, containing granules of dark purplish-red. The variability of mast cell distribution shown in this study emphasizes the need for large tissue samples in any estimation of mast cell numbers.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Clinical Anatomy 4 (1991), S. 200-211 
    ISSN: 0897-3806
    Keywords: human nasal mucosa ; cellular associations ; Life and Medical Sciences ; Miscellaneous Medical
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Tissue taken from 20 patients during inferior turbinectomy was examined to elucidate the ultrastructure of mast cells, previously studied histologically, when we had noted differences in their size, granule content and staining characteristics, in epithelium, superficial and deep tunica propria of nasal mucosa.This ultrastructural study revealed that intra-epithelial mast cells were common, but often had fewer and more irregularly shaped granules than those in other areas. Mast cells were numerous in superficial tunica propria; they were small and spindle-shaped, with relatively few roundish granules, and appeared motile. Those in deeper tunica propria were larger and round or ovoid, with many roundish granules. The deeply located cells were fewer and often totally surrounded by large areas of collagen fibers. Association of mast cells with other cells was frequently noted, particularly in superficial layers, often with attenuated processes of fibroblasts and also frequently with one or more plasma cells or another mast cell.Although mast cells and unmyelinated or myelinated nerve were frequently seen in close association, specialized nerve endings were never observed.The distribution of mast cells and their granule characteristics correlates well with our earlier published histological observations.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
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