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  • 1
    Electronic Resource
    Electronic Resource
    [S.l.] : International Union of Crystallography (IUCr)
    Acta crystallographica 24 (1968), S. 191-199 
    ISSN: 1600-5724
    Source: Crystallography Journals Online : IUCR Backfile Archive 1948-2001
    Topics: Chemistry and Pharmacology , Geosciences , Physics
    Notes: The angular and voltage dependence of the diffracted intensity for electrons in the energy range of 150–900 volts from a clean tungsten (110) surface has been measured with a single-crystal diffractometer. Selecting the angle of incidence and the electron wavelength to satisfy the Bragg condition the crystal is rotated about its normal, and a Renninger plot of diffracted intensity versus azimuthal angle is made. Strong intensity variations are observed when the plane of diffraction is parallel to those low index crystallographic planes which contain relatively dense atomic rows. Additional structure occurs for each intersection of an extended reciprocal lattice point with the Ewald sphere. For some orientations the intensity is reduced to half the value within one degree, which is the beam divergence. When simultaneous diffraction does not occur, the intensities of the Bragg maxima are close to the background. The integral order Bragg maxima observed in electron diffraction are thus shown to have their origin in multiple diffraction. The frequently observed fractional order Bragg maxima are predicted to have the same origin. Renninger plots for such maxima show this to be the case. In addition the appearance of the fractional order peaks should depend only on the geometry for multiple diffraction. Intensity versus voltage curves for the beam incident along the [hkl] direction are predicted to have maxima of order (h2 + k2 + l2)−1, which is verified. The implication of these observations in terms of previous two-beam models is discussed.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    [S.l.] : International Union of Crystallography (IUCr)
    Acta crystallographica 25 (1969), S. 393-394 
    ISSN: 1600-5724
    Source: Crystallography Journals Online : IUCR Backfile Archive 1948-2001
    Topics: Chemistry and Pharmacology , Geosciences , Physics
    Notes: Strong minima in the rotation diagram about the 550 Bragg reflection from the (110) surface of tungsten are interpreted as being due to the excitation of forward diffracted Laue reflections having low index and large wave amplitude. The orientations of these minima correspond to the geometry for the excitation of the three beam case.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    Industrial & engineering chemistry 39 (1947), S. 1000-1007 
    ISSN: 1520-5045
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Science Ltd
    Alimentary pharmacology & therapeutics 19 (2004), S. 0 
    ISSN: 1365-2036
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Background : Meal ingestion has been suggested to reduce susceptibility to the development of gastric tachyarrhythmia, the abnormal activity of the stomach that frequently accompanies nausea.Aim : To determine the types of meal that are most effective in preventing the development of gastric tachyarrhythmia, nausea and the symptoms of motion sickness provoked by a rotating optokinetic drum.Method : Participants received a carbohydrate beverage, a protein-predominant beverage or nothing immediately before exposure to the rotating drum. Subjective symptoms of motion sickness and electrogastrograms were collected during a 6-min baseline period and a subsequent 16-min drum rotation period.Results : Subjective symptoms of motion sickness scores were significantly more severe during the no-meal condition than during either the protein or carbohydrate condition. Central, peripheral and, to some extent, gastrointestinal symptoms were more severe during the carbohydrate condition than during the protein condition. Gastric tachyarrhythmia increased significantly less from baseline to drum rotation during both the protein and carbohydrate conditions than during the no-meal condition.Conclusions : Liquid protein-predominant meals were most effective in suppressing both the development of gastric tachyarrhythmia and the entire spectrum of motion sickness symptoms, including nausea.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    International archives of occupational and environmental health 57 (1986), S. 237-246 
    ISSN: 1432-1246
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Digestive diseases and sciences 35 (1990), S. 961-968 
    ISSN: 1573-2568
    Keywords: electrogastrography ; pregnancy ; vomiting ; spectral analysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Gastric dysrhythmias have been recorded from patients with a variety of nausea syndromes. The aim of this study was to measure gastric myoelectric activity in women with and without nausea during the first trimester of pregnancy. In 32 pregnant women gastric myoelectric activity was recorded for 30–45 min with cutaneous electrodes that yielded electrogastrograms (EGGs). Frequencies of the EGG waves were analyzed visually and by computer. Subjects rated their nausea at the time of EGG recording on a visual analog scale with 0 representing no nausea and 300 mm severe nausea. Gastric dysrhythmias were found in 26 pregnant subjects: Seventeen had tachygastrias (EGG frequencies of 4–9 cpm),five had 1- to 2-cpm EGG waves, and four had flat-line patterns. Mean nausea scores of the subjects with tachygastrias, 1- to 2-cpm, and flat-line patterns were 64.8±13, 93.4±23, and 77.2±36, respectively. Six pregnant subjects had normal 3-cpm EGG patterns, and their nausea scores averaged 2.8±1.1 (P〈0.05 compared with nausea scores in subjects with tachygastrias, 1- to 2-cpm, and flat-line rhythms). Six subjects with gastric dysrhythmias during pregnancy were restudied after delivery; each of these subjects had normal 3-cpm EGG patterns and none had nausea. Thus, gastric dysrhythmias are objective pathophysiologic events associated with symptoms of nausea reported during the first trimester of pregnancy.
    Type of Medium: Electronic Resource
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