RESUMEN
Understanding the micro-mechanisms underlying the localized-ductile transition (LDT) as well as the brittle-plastic transition (BPT) has become crucial for our wider understanding of crustal processes and seismicity. Given how difficult in situ observations of these transitions are to perform, laboratory experiments might be our only way to investigate the processes active under these conditions (high T and high P). Here, we present Triaxial AppaRatus for GEoThermal energy, a new gas-based triaxial apparatus located at EPFL in Switzerland that was specifically designed to operate under conditions where both the LDT and BPT can occur in geomaterials. We show that the machine is capable of deforming rock samples at confining pressures of up to 400 MPa, temperatures of up to 800 °C, and pore pressures (liquid or gas) of up to 300 MPa while keeping the temperature gradient along samples of 40 mm in length and 20 mm in diameter minimal (less than 30 at 700 °C). Most importantly, the maximum load is 1000 kN (stresses as high as 2.2 GPa on 24 mm samples and 3 GPa on 20 mm samples), allowing for the deformation of very competent rock samples. Moreover, during deformation, the pair of syringe pore pressure pumps allow for continuous permeability or dilatancy recording. We benchmarked our machine against existing data in the literature and show that it accurately and precisely records stress, strain, permeability, pressure, and temperature.
RESUMEN
To establish methodological standards for serological investigation and screening of coeliac disease, a joint venture has been launched by the European Medical Research Council and the European Society for Paediatric Gastroenterology and Nutrition. Before general screening can be recommended, robust methods and technical standards ought to be introduced. Joint test protocols were defined: an enzyme-linked immunosorbent assay for IgG and IgA gliadin antibodies and an immunofluorescent test for IgA endomysium antibodies. Protocols have now been tested prospectively by one laboratory. Eighty-eight Tuebingen patients were studied (47 coeliac disease on normal diet, 22 coeliac disease on a gluten-free, and 19 disease controls). Single tests did not produce acceptable levels, but combinations of IgA gliadin antibodies and IgA endomysium antibodies showed 98% sensitivity, 100% specificity and 98% predictive efficiency. Only standardized and refereed methods established by ring testing can serve as a reliable basis for serological coeliac screening.
