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  • 1990-1994  (1)
  • 1980-1984  (1)
  • Friedreich ataxia  (1)
  • Heterogeneous  (1)
  • 1
    ISSN: 1432-0495
    Keywords: Groundwater ; Porous aquifer ; Heterogeneous ; Biological tracers ; Bacteriophage ; Fluorescent dye ; Naphthionate ; Electromagnetic survey
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Notes: Abstract This article presents an example of a tracing experiment using two bacteriophages, T7 and f1, and a fluorescent dye (naphthionate), in a saturated porous environment. The test field was equipped with an injection borehole and 22 sampling piezometers set in three concentric half-circles. The distribution of permeabilities and the thickness of the aquifer were indirectly determined by Radio-Magneto-Tellury (RMT, 12–240 kHz). The results reveal a good correlation between the distribution of permeabilities obtained by RMT and the breakthrough curves and speed of migration of all three tracers. The restitution levels are far superior (by two to three orders of magnitude) in the more permeable zones, as opposed to those observed in th piezometers situated in less permeable areas. The speed of migration of the biological tracers is much greater than that of the naphthionate. In the most extreme case, the T7 bacteriophage migrated about 3.15 times faster than the chemical solution. These results indicate that bacteriophages are able to travel considerable distances along permeable gravel channels. They may be used as biological tracers and as models for the migration of pathogenic viruses. The simultaneous use of tracing techniques and appropriate geophysical methods leads to a better knowledge of the hydrogeological parameters of the underground terrain. This combination allows for a better interpretation both of the speeds of migration and of the maximal concentrations of the tracers, and thus considerably increases the interpretability of hydrogeological impact studies.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1590-3478
    Keywords: Pyruvate-dehydrogenase ; Friedreich ataxia ; lactic acidosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Sommario Il complesso enzimatico piruvico-deidrogenasi (PDHC) è stato misurato in fibroblasti coltivati da 12 pazienti con atassia di Friedreich ed 1 paziente con acidosi lattica e atassia. Le attività enzimatiche ottenute con diversi metodi di estrazione del PDHC sono stati confrontati. La estrazione con Triton-X-100 permetteva di ottenere attività enzimatiche da 5 a 10 volte più elevate di quelle ottenute con i metodi precedenti. Con questo sensibile metodo l'attività PDHC era molto ridotta nei fibroblasti del paziente con acidosi lattica e atassia: l'attività era invece normale nei fibroblasti dei pazienti con atassia di Friedreich. La attivazione del PDHC nei fibroblasti dei pazienti con Friedreich era normale.
    Notes: Abstract Pyruvate dehydrogenase complex (PDHC) activity was measured in cultured fibroblasts from 12 patients with Friedreich's ataxia (FA), and in 1 patient with lactic acidosis and ataxia. The activities obtained after extraction of PDHC by different methods were compared. Triton-X-100 extraction yielded enzyme activities 5 to 10 times greater than those obtained with the older methods. With this sensitive technique, PDHC activity was markedly deficient in fibroblasts from the patient with lactic acidosis and ataxia but it was normal in the fibroblasts from FA patients. Mg ++ activation of the PDHC in FA fibroblasts was normal.
    Type of Medium: Electronic Resource
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