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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Surveys in geophysics 17 (1996), S. 347-360 
    ISSN: 1573-0956
    Keywords: Ultrasonic waves ; Attenuation ; Velocity ; Microstructure ; Thermal cracking ; Local fluid flow
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract The frequency dependent mechanism of local fluid flow was found to be the decisive absorption and dispersion mechanism in fluid containing sandstones. In the ultrasonic frequency range local fluid flow and grain surface effects control the behaviour of highly porous and highly permeable rock if a pore fluid is present. Both mechanisms depend less on macroscopic rock parameters like porosity and permeability than essentially on microscopic parameters like crack size, crack density and grain contact properties. To demonstrate directly the important influence of the microstructure on the rock elastic and anelastic properties the microstructure of a sandstone was artificially changed by thermal cracking. The cracked rock exhibits a clearly changed behaviour at low uniaxial as well as at high hydrostatic pressure despite small changes of porosity and permeability. Fluid effects increase due to cracking. The experimental results are explained by means of a rock, model and local fluid flow. These results emphasize that it is the microstructure which controls the elastic and anelastic rock behaviour, even at high hydrostatic pressure.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Rheumatology international 17 (1997), S. 85-90 
    ISSN: 1437-160X
    Keywords: Key words Immunosuppressive drugs ; Autoimmune disease ; Animal models
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract An unprecedented arsenal of new xenobiotic immunosuppressive agents has been developed recently. Most of the new immunosuppressants have been tested primarily in the treatment of allograft rejection in experimental models of transplantation, and some of the new drugs have already proven their safety and efficiency in extensive clinical trials on transplant patients. Another field for their potential application is the treatment of autoimmune diseases. This review will give an overview of the therapeutic potential of the new xenobiotic drugs in different animal models of rheumatoid arthritis, systemic lupus erythematosus, myasthenia gravis, multiple sclerosis, diabetes mellitus, thyroiditis and uveoretinitis. The new xenobiotics are either inhibitors of the de novo synthesis of nucleotides, for example mycophenolate mofetil, mizoribine, leflunomide, and brequinar, or are immunophilin-binding agents (cyclosporin, FK506 and rapamycin) that inhibit signal transduction and cell cycle progression in lymphocytes. A different mode of action is likely to account for the immunosuppressive effects of deoxyspergualin, which may interfere with intracellular chaperoning by the heat shock protein HSP70 and the activation of transcription factor NF-kappa B.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
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