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  • 1
    Electronic Resource
    Electronic Resource
    [S.l.] : International Union of Crystallography (IUCr)
    Acta crystallographica 34 (1978), S. 116-120 
    ISSN: 1600-5724
    Source: Crystallography Journals Online : IUCR Backfile Archive 1948-2001
    Topics: Chemistry and Pharmacology , Geosciences , Physics
    Notes: Lattice fringes corresponding to (00.3) spacings of the 126R polytype of SiC have been obtained in the electron microscope. A number of 10.l reflections were allowed to pass through the objective aperture to obtain the lattice fringes showing a periodicity of ̃105 Å (one third of the c parameter of the hexagonal cell) and each unit-cell block is subdivided into smaller blocks corresponding to the spacings of 6H, 15R, 21R etc. The stacking sequence of these blocks has been used to work out the detailed structure of the 126R polytype. It has been suggested that the lattice resolution technique in conjunction with X-ray diffraction is likely to prove a useful method for determining difficult polytypic structures.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    [S.l.] : International Union of Crystallography (IUCr)
    Acta crystallographica 33 (1977), S. 276-279 
    ISSN: 1600-5724
    Source: Crystallography Journals Online : IUCR Backfile Archive 1948-2001
    Topics: Chemistry and Pharmacology , Geosciences , Physics
    Notes: Extremely large-period polytypes in SiC have been investigated by single-crystal X-ray diffraction and direct lattice imaging by electron microscopy, which has been found to be a more suitable technique for studying structures of extremely large periodicities. Some crystals giving rise to a diffuse streaking along h0.l reciprocal lattice rows when studied by X-ray diffraction, showed the presence of extremely long- period polytypes when investigated by electron microscopy. The c periodicity of such SiC structures (having periodicities of more than 1000 Å) has been determined by this technique and the super-period block spacing is found to contain block spacings of 6H, 15R, 4H and 21R polytypes.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    Inorganica Chimica Acta 33 (1979), S. 15-22 
    ISSN: 0020-1693
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 79 (1996), S. 7157-7160 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Germanium films were deposited on GaAs (100) substrates with or without an epiready surface oxide at temperatures between room temperature (RT) and 500 °C using an ultrahigh-vacuum e-beam deposition system. The film at 100 °C on a substrate with a surface oxide had a flat absorption curve over the wave-number range investigated, 500–4000 cm−1, with an absorption of less than 10/cm at 1000 cm−1 (10 μm wavelength). Films deposited at RT and 50 °C on substrates with a surface oxide had comparable low absorption, but they contained an absorption peak at 830 cm−1 associated with the Ge—O bonds. Although all three films were amorphous, the films deposited at the lower temperatures were more porous. This enabled oxygen to percolate in from the atmosphere to form the Ge—O bonds. The films deposited at 150 °C and above on substrates with a surface oxide and at 100 °C with the surface oxide removed thermally in situ prior to deposition the Ge films, and the single crystal films deposited at 400 and 500 °C on oxide-free substrates, had strong absorption in the vicinity of the Ge/GaAs interface with the characteristic of two-dimensional free-carrier absorption. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 64 (1994), S. 2697-2699 
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Single crystal germanium films were deposited on (100) GaAs and InGaP substrates, and highly oriented gold films were deposited on the germanium films by ultrahigh vacuum E-beam evaporation. They were characterized by double crystal x-ray diffraction (DXRD), transmission electron microscopy (TEM), Rutherford backscattering spectroscopy (RBS), Auger electron spectroscopy (AES), and scanning electron microscopy (SEM). The germanium film grew epitaxially with a smooth, abrupt interface, and the highly oriented gold film formed a smooth interface with the germanium and had a (100)Au(parallel)(100)Ge and (001)Au(parallel)[011]Ge or [001]Au(parallel)[0-1 1]Ge orientation relationship. Large grains with one or the other orientation relationship could be distinguished in the SEM. TEM micrographs show that the grains have a periodic dislocation pattern indicative of heteroepitaxy, and the grain boundaries appear to have a low energy. No contamination was detected in the gold film away from the interface with the germanium, and there was significant channeling of the RBS beam when it was normal to the gold film.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Copenhagen : International Union of Crystallography (IUCr)
    Applied crystallography online 7 (1974), S. 515-518 
    ISSN: 1600-5767
    Source: Crystallography Journals Online : IUCR Backfile Archive 1948-2001
    Topics: Geosciences , Physics
    Notes: Unusual SiC polytypic features have been studied by X-ray diffraction and chemical etching to increase understanding of their growth mechanism. The feasibility of periodic slip as a possible mode of growth of SiC polytypes has been examined. It is proposed that island formation on the helicoidal growth surface is responsible for most of the unusual SiC polytypes not explicable purely in terms of a screw-dislocation mechanism.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Copenhagen : International Union of Crystallography (IUCr)
    Acta crystallographica 29 (1973), S. 1548-1550 
    ISSN: 1600-5740
    Source: Crystallography Journals Online : IUCR Backfile Archive 1948-2001
    Topics: Chemistry and Pharmacology , Geosciences , Physics
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Naunyn-Schmiedeberg's archives of pharmacology 291 (1975), S. 1-15 
    ISSN: 1432-1912
    Keywords: Heart ; Noradrenaline release ; Potassium ; Calcium ; Methacholine
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary 1. Noradrenaline release from the isolated rabbit heart was evoked by perfusion with a medium containing 135 mM potassium and 17 mM sodium ions (high K+-low Na+). 2. The noradrenaline output in response to high K+-low Na+ was dose-dependently decreased by methacholine (0.625–320 μM) and this effect was reserved by atropine 1.44 μM. 3. Lowering the calcium concentration of high K+-low Na+ from 1.8–0.1125 mM decreased the noradrenaline output by 85%. The effect of methacholine, expressed as % inhibition of noradrenaline release, was potentiated by lowering of the calcium concentration. 4. Both at normal and lowered calcium concentrations the inhibitory action of methacholine was larger from 0–5 than from 5–10 min after perfusion with high K+-low Na+. 5. Perfusion of hearts with media containing high K+-high Na+ or normal K+-low Na+ caused noradrenaline outputs somewhat smaller than those after high K+-low Na+. The release from 0–5 min was both calcium-dependent and inhibited by methacholine. 6. High K+ and/or low Na+ solutions caused an increase in coronary perfusion pressure which was little affected by the noradrenaline released simultaneously. 7. It is concluded that activation of muscarine receptors at the terminal adrenergic fibre decreases the availability of calcium for transmitter release.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Annals of hematology 61 (1990), S. 314-316 
    ISSN: 1432-0584
    Keywords: Transfusion malaria ; Thalassaemia ; Antigen detection
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A total of 125 β-thalassaemia patients receiving repeated blood transfusions were screened by Giemsa stain, Acridine-orange stain and antigen detection for evidence of malaria infection on each visit. A total of 8 (6.4%) of the patients developed post-transfusion malaria (PMT) as confirmed by tracing the infected blood donors. A high incidence of PTM in thalassaemia patients appears to be due to the use of fresh blood and the high frequency of blood transfusions required by these patients. Antigen detection using monoclonal antibody was found to be more sensitive for diagnosis of PTM and for screening suspected donors than the conventional blood smear examination methods and is therefore recommended for routine blood donor screening to rule out malaria infection.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Springer
    Annals of hematology 65 (1992), S. 131-134 
    ISSN: 1432-0584
    Keywords: Malaria ; Plasmodium falciparum ; Erythrocyte ; Lipid peroxidation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The extent of reduced glutathione, activity of glutathione peroxidase, amount of membrane lipid peroxidation products, and the extent of hemoglobin release from host erythrocytes during in vitroPlasmodium falciparum growth was studied. Highly synchronized parasite cultures were studied to examine the alterations caused by different growth stages of the parasite. There was a moderate increase in the reduced glutathione content as the parasite matured, which was significant only in schizontrich erythrocyte lysates (p〈0.05) whereas the activity of glutathione peroxidase was significantly low in all the parasitized red blood cells (ring-infected RBC,p〈0.005; trophozoite- and schizont-infected RBC,p〈0.001). The lipid peroxidation product, malonyldialdehyde, of the host red cells increased gradually to more than fourfold in schizont-rich cells as compared with normal erythrocytes (p〈0.001). The hemoglobin release from cultured cells was significantly higher in all parasitized red cell cultures as well as in uninfected cells kept in in vitro, as compared with normal erythrocytes. The consequence of such changes induced by the malarial parasites in the host red cells in the pathogenesis of erythrocyte destruction and anemia ofP. falciparum malaria is discussed.
    Type of Medium: Electronic Resource
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