Mineral-doped poly(L-lactide) acid scaffolds enriched with exosomes improve osteogenic commitment of human adipose-derived mesenchymal stem cells

Exosomes derived from mesenchymal stem cells are extracellular vesicles released to facilitate cell communication and function. Recently, polylactic acid (PLA), calcium silicates (CaSi), and dicalcium phosphate dihydrate (DCPD) have been used to produce bioresorbable functional mineral-doped porous scaffolds-through thermally induced phase separation technique, as materials for bone regeneration. The aim of this study was to investigate the effect of mineral-doped PLA-based porous scaffolds enriched with exosome vesicles (EVs) on osteogenic commitment of human adipose mesenchymal stem cells (hAD-MSCs). Two different mineral-doped scaffolds were produced: PLA-10CaSi-10DCPD and PLA-5CaSi-5DCPD. Scaffolds surface micromorphology was investigated by ESEM-EDX before and after 28 days immersion in simulated body fluid (HBSS). Exosomes were deposited on the surface of the scaffolds and the effect of exosome-enriched scaffolds on osteogenic commitment of hAD-MSCs cultured in proximity of the scaffolds has been evaluated by real time PCR. In addition, the biocompatibility was evaluated by direct-contact seeding hAD-MSCs on scaffolds surface-using MTT viability test. In both formulations, ESEM showed pores similar in shape (circular and elliptic) and size (from 10\u201330 \ub5m diameter). The porosity of the scaffolds decreased after 28 days immersion in simulated body fluid. Mineral-doped scaffolds showed a dynamic surface and created a suitable bone-forming microenvironment. The presence of the mineral fillers increased the osteogenic commitment of hAD-MSCs. Exosomes were easily entrapped on the surface of the scaffolds and their presence improved gene expression of major markers of osteogenesis such as collagen type I, osteopontin, osteonectin, osteocalcin. The experimental scaffolds enriched with exosomes, in particular PLA-10CaSi-10DCPD, increased the osteogenic commitment of MSCs. In conclusion, the enrichment of bioresorbable functional scaffolds with exosomes is confirmed as a potential strategy to improve bone regeneration procedures

Indus potters in central Oman in the second half of the third millennium BC. First results of a technological and archaeometric study

International audienceThe nature of cultural interactions between the Indus Civilization and Magan is explored in this paper. The presence of Indus potters in eastern Arabia can now be demonstrated based on a combined technological and petrographical study of a range of pottery types found at the site of Salūt ST1 (Sultanate of Oman). Similar discoveries from other Umm an-Nar sites in the Sultanate of Oman and the UAE supports the hypothesis that Indus communities were living alongside the Magan people at Umm an-Nar sites more extensively than previously thought

Indus potters in central Oman in the second half of the third millennium BC. First results of a technological and archaeometric study

International audienceThe nature of cultural interactions between the Indus Civilization and Magan is explored in this paper. The presence of Indus potters in eastern Arabia can now be demonstrated based on a combined technological and petrographical study of a range of pottery types found at the site of Salūt ST1 (Sultanate of Oman). Similar discoveries from other Umm an-Nar sites in the Sultanate of Oman and the UAE supports the hypothesis that Indus communities were living alongside the Magan people at Umm an-Nar sites more extensively than previously thought

Sparre-Andersen theorem with spatiotemporal correlations

The Sparre-Andersen theorem is a remarkable result in one-dimensional random walk theory concerning the universality of the ubiquitous first-passage-time distribution. It states that the probability distribution \u3c1n of the number of steps needed for a walker starting at the origin to land on the positive semiaxes does not depend on the details of the distribution for the jumps of the walker, provided this distribution is symmetric and continuous, where in particular \u3c1n 3cn-3/2 for large number of steps n. On the other hand, there are many physical situations in which the time spent by the walker in doing one step depends on the length of the step and the interest concentrates on the time needed for a return, not on the number of steps. Here we modify the Sparre-Andersen proof to deal with such cases, in rather general situations in which the time variable correlates with the step variable. As an example we present a natural process in 2D that shows that deviations from normal scaling are present for the first-passage-time distribution on a semiplane

Secondary structure analysis of the dissimilatory sulphite reductase in Desulfovibrio desulfuricans

The complete sequences of the dsrA and dsrB genes coding for the α− and β−subunits, respectively, of the sulphite reductase enzyme in Desulfovibrio desulfuricans were determined. Analyses of the amino acid sequences indicated a number of serohaem/Fe4S4 binding consensus sequences whilst predictive secondary structure analysis revealed a similar pattern of α−helix and β−strand structures between the two subunits which was indicative of gene duplication

ASSESSING LONG-TERM HAZARDS FOR LA SOUFRIERE OF GUADELOUPE VOLCANO: INSIGHTS FROM A NEW ERUPTIVE CHRONOLOGY, CREDIBLE SCENARIO DEFINITION, AND INTEGRATED IMPACT MODELLING

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