1,721,097 research outputs found
The sealed osteons of cortical diaphyseal bone. Early observations revisited with scanning electron microscopy.
No full textThe frequency, structure, mode of formation and significance of
sealed osteons remain unsettled. Sealed osteons have been reported as an
unusual finding in the cortical bone of experimental animals: we extended
the observation to human cortical bone studied with SEM. Tibial bone
specimens from three patients who sustained a traumatic below-the-knee
amputation were used in the study. The observed total mean density of
osteons was 19.25/mm2 and the percentage of sealed and partially sealed
osteons was 4.2% and 1.7% respectively. The material sealing the central
canal showed an X-ray microanalysis spectrum with the same Ca/P ratio
as the peripheral lamellae and a lower carbon signal. The morphology
suggested a reactivation of bone apposition triggered by exclusion of the
occluded canal from blood flow rather than a physiological evolution of
the closing process of secondary osteons. This presupposes collapse and
degeneration of the central vessel before the osteoblasts resting on the
inner surface of the canal could start to lay down new bone matrix. This
explanation is consistent with a dynamic model of intracortical blood flow
Imageability of Geo-Mining Heritage. Case Study of Nebida Settlement, Geo-Mining Park Sardinia (Italy)
No full textWith respect to the scale of observation and the low-urbanized context, this paper argues perceptual qualities that help the interpretation of heritage settings experienced by walking. Focused on physical environmental indicators and aesthetic qualities to be used in Geo-mining heritage settings, the paper redefined qualities of visual impact from previous findings including geometric features of a path (profile and edges) and imageability as comprehensive perceptual quality. Selected indicators were implemented at two selected routes in the ex-mining settlement of Nebida. Results demonstrated relationships between indicators of path geometry and of imageability; the more complex geometry, the more diverse imageability and experience of walking. Moreover, in the case of Nebida, a planned and maintained route offers a less direct and variable experience of Geo-mining heritage than an informal track beaten by hikers
Structural Aspects of the Extracellular Matrix of Tendon: An Atomic Force and Scanning Electron Microscopy Study
No full textL’approccio process-oriented nella pianificazione deli territorio di bordo dell’area vasta di Cagliari
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“L’approccio process-oriented per l’integrazione tra dinamiche ecologiche e forme di gestione della città, ”
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