Biopolymer-based membranes associated with osteogenic growth peptide for guided bone regeneration

Barrier membranes for guided bone regeneration (GBR) mainly promote mechanical maintenance of bone defect space and induce osteopromotion. Additionally, biopolymer-based membranes may provide greater bioactivity and biocompatibility due to their similarity to extracellular matrix (ECM).In this study, biopolymers-based membranes from bacterial cellulose (BC) and collagen (COL) associated with osteogenic growth peptide (OGP(10–14)) were evaluated to determine in vitro osteoinductive potential in early osteogenesis; moreover, histological study was performed to evaluate the BC–COL OGP(10–14) membranes on bone healing after GBR in noncritical defects in rat femur. The results showed that the BC–COL and BC–COL OGP(10–14) membranes promoted cell proliferation and alkaline phosphatase activity in osteoblastic cell cultures. However, ECMmineralization was similar between cultures grown on BC OGP(10–14) and BC–COL OGP(10–14) membranes. In vivo results showed that all the membranes tested, including the peptide-free BC membrane, promoted better bone regeneration than control group. Furthermore, the BC–COL OGP(10–14) membranes induced higher radiographic density in the repaired bone than the other groups at 1, 4 and 16 weeks. Histomorpho-metric analyses revealed that the BC–COL OGP(10–14) induced higher percentage of bone tissue in the repaired area at 2 and 4 weeks than others membranes. In general, these biopolymer-based membranes might be potential candidates for bone regeneration applications

Blast-induced liquefaction in silty sands for full-scale testing of ground improvement methods: Insights from a multidisciplinary study

In the engineering geology field increased attention has been posed in recent years to potential liquefaction mitigation interventions in susceptible sand formations. In silty sands this is a major challenge because, as the fines content increases, vibratory methods for densification become progressively less effective. An alternative mitigation technique can be the installation of Rammed Aggregate Pier\uae (RAP) columns that can increase the resistance of the soil, accounting for its lateral stress increase and for the stiffness increase from soil and RAP composite response. To investigate the influence of these factors on liquefaction resistance, full-scale blast tests were performed at a silty sand site in Bondeno (Ferrara, Italy) where liquefaction was observed after the 2012 Emilia-Romagna earthquake. A multidisciplinary team of forty researchers carried out devoted experimental activities aimed at better understanding the liquefaction process at the field scale and the effectiveness of the treatment using inter-related methods. Both natural and improved areas were investigated by in-situ tests and later subjected to controlled blasting. The blast tests were monitored with geotechnical and geophysical instrumentation, topographical surveying and geological analyses on the sand boils. Results showed the RAP effectiveness due to the improvement of soil properties within the liquefiable layer and a consequent reduction of the blast-induced liquefaction settlements, likely due to soil densification and increased lateral stress. The applied multidisciplinary approach adopted for the study allowed better understanding of the mechanism involved in the liquefaction mitigation intervention and provided a better overall evaluation of mitigation effectiveness

Stress increase induced by impact precast pile driving

The paper describes the experimental activities carried out in a test site, set up to evaluate the increase of soil stiffness and horizontal effective stress, mainly in saturated low-medium density sandy layers and in silty sand, after the driving of tapered precast piles. The experimentation consisted in driving some prefabricated tapered piles with different energies and spacing between them in an area where some soil layers had a high liquefaction potential. To evaluate the pile driving effects on the stress state around them, preliminary CPTu and DMT tests were carried out and repeated after the driving activity. In particular, the change of the CPTu sleeve resistances was compared with that of the DMT KD data, to evaluate the increase in horizontal stress using different methods, a phenomenon influencing the soil susceptibility to liquefaction and the pile bearing capacity

Discovering forgeries of modern art by the 14C Bomb Peak

Exploiting the anomalous behaviour of the atmospheric radiocarbon concentration in the years after 1955 (so-called “Bomb Peak”), an alleged painting by Fernard Léger was unambiguously proven to be a fake just by dating the canvas support. Some art historians had questioned the authenticity of the painting, and their suspicions were fuelled by some scientific examinations of the paint materials (X-ray radiography, SEM-EDS), compared to those of another work unquestionably attributed to Léger. The decisive argument to prove that it was a fake was provided by the radiocarbon date obtained from a sample of canvas of the painting, using Accelerator Mass Spectrometry at the INFN-Labec laboratory in Florence. Beyond any doubt, the cotton plant from which the canvas was produced was cut no earlier than 1959, i.e. four years after Léger’s death, thus definitely confirming the concerns of a fake