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Geraci, G. – Marcone, A. (2008) Fonti per la storia romana
No full textGERACI, G. – MARCONE, A. (2008) Fonti per la storia romana, Firenze,Le Monnier Università, 539 pp., ISBN: 978‐880‐08‐6068
Microbes in rocks and meteorites: A new form of life unaffected by time, temperature, pressure
No full textCrystals, rocks and mineral ores of different origins contain viable microbial life that appears actively swimming under the microscope when the sample is properly fragmented and suspended in a nutrient medium. This form of life in rocks is unaffected by time, since microbes have been found in samples of all geological ages, from about 2.8 Ga to recent rocks, and by pressure and temperature, since it is present in metamorphic and in igneous rocks. From the tests performed, among which those to secure from sample pollution, it emerges that this form of life is not destroyed, as indeed expected, when the rock is heated above 500 °C in a kiln. However, all cloned microbes are sensitive to growth inhibition by specific antibiotics. A similar search, for the presence of microbes in meteorites, shows that also these materials are rich in microorganisms, indicating that these already existed in early Earth formation stages. Some different microbial species, derived from different samples of rocks and meteorites, have been cultured, cloned and classified by 16S rDNA typing and found to be not essentially different from present day organisms An interesting consequence of these findings, among others, is the support to the hypothesis that life came from outside Earth with the additional indication that it was already present in those materials that accreted to form the solar planetary system
Effects of voids and flaws on the mechanical properties and on intergranular damage and fracture for polycrystalline materials
Full text linkIt is widely recognized that the macroscopic material properties depend on the features
of the microstructure. The understanding of the links between microscopic and macroscopic
material properties, main topic of Micromechanics, is of relevant technological interest, as it may
enable the deep understanding of the mechanisms governing materials degradation and failure.
Polycrystalline materials are used in many engineering applications. Their microstructure is
determined by distribution, size, morphology, anisotropy and orientation of the crystals. It worth
noting that also the physical-chemical properties of the intergranular interfaces, as well as the
presence of micro-imperfections within the microstructure, have to be taken into account, as they
may have to a strong influence on onset and evolution of damage
Evidences on arginine-lysine side chains interaction for the formation aggregational states of the H1 histone
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