How can research on modern and fossil bones help us build more resistant columns?

Bone is an economical material. Indeed, as moving a heavy skeleton is energetically costly, the vertebrate skeleton is adapted to maximise resistance to the stresses imposed with a minimum amount of material, so that bone tissue is deposited where it is needed. Using bone as a source of inspiration should therefore reduce the manufacturing cost (both financial and ecological) and increase the strength (and lifespan) of bioinspired (BI) structures. This study proposes to investigate which adaptive features of the outer shape and inner structure of bone, related to compressive strength, could be used to build BI support structures. To do so, we explain the choice of the bones to be analysed and present the results of the biomechanical analyses (finite element analysis) carried out on virtual models built from the structures of the different bone models and of the mechanical tests carried out on 3D-printed versions of these models. The compressive strength of these direct bone BI columns was compared with each other, and with those of a conventional filled cylindrical column, and of a cylindrical column whose internal structure is BI from the radius of the white rhinoceros. The results of our comparative analyses highlight that the shape of long bones is less effective than a cylinder in resisting compression but underline the relevance in designing BI cylindrical columns with heterogeneous structures inspired by the radius of the white rhinoceros and the tibia of the Asian elephant, and raise the interest in studying the fossil record using the radius of the giant rhinocerotoidParaceratherium.

Comparison of ranitidine and sucralfate in the long-term treatment of duodenal ulcer

We evaluated long-term treatment with either ranitidine (R) or sucralfate (S) in the prevention of duodenal ulcer recurrences. Fifty-nine patients with healed ulcers were randomly allocated to maintenance treatment with 150 mg R nightly or 2 g/day S. By using a life table analysis, the calculated probable remission rates at 4, 8, and 12 months were 90, 85, and 53% with R, respectively, and 62, 62, and 53% with S, respectively. These differences were not significant at any interval. In both groups ulcer relapse was independent of sex, smoking habit, and alcohol and coffee consumption, whereas a history longer than 5 years was significantly related to a higher probability of recurrence. No relevant clinical or biochemical side effects were encountered with either drug, but compliance rate was higher in the R group. R and S are equally effective in preventing duodenal ulcer relapse over a 1-year period of maintenance treatment, although R proved to be more effective in preventing early relapse.