Comprehensive in vitro and in vivo studies of novel melt-derived Nb-substituted 45S5 bioglass reveal its enhanced bioactive properties for bone healing

The present work presents and discusses the results of a comprehensive study on the bioactive properties of Nb-substituted silicate glass derived from 45S5 bioglass. In vitro and in vivo experiments were performed. We undertook three different types of in vitro analyses: (i) investigation of the kinetics of chemical reactivity and the bioactivity of Nb-substituted glass in simulated body fluid (SBF) by 31P MASNMR spectroscopy, (ii) determination of ionic leaching profiles in buffered solution by inductively coupled plasma optical emission spectrometry (ICP-OES), and (iii) assessment of the compatibility and osteogenic differentiation of human embryonic stem cells (hESCs) treated with dissolution products of different compositions of Nb-substituted glass. The results revealed that Nb-substituted glass is not toxic to hESCs. Moreover, adding up to 1.3 mol% of Nb2O5 to 45S5 bioglass significantly enhanced its osteogenic capacity. For the in vivo experiments, trial glass rods were implanted into circular defects in rat tibia in order to evaluate their biocompatibility and bioactivity. Results showed all Nb-containing glass was biocompatible and that the addition of 1.3 mol% of Nb2O5, replacing phosphorous, increases the osteostimulation of bioglass. Therefore, these results support the assertion that Nb-substituted glass is suitable for biomedical applications

Milieux naturels, espaces sociaux

Robert Delort se distingue par l'ampleur et l'originalité du champ de sa réflexion historique. Il a abordé, grâce à sa maîtrise des méthodes de la recherche historique les plus diversifiées, de la linguistique à l'archéologie, des statistiques à l'analyse littéraire et iconographique, aussi bien l'histoire économique, sociale et politique du Moyen Âge, que celle des comportements ou encore de la biologie des espèces animales. Il n'est donc pas étonnant que Robert Delort ait orienté ses recherches et celles de ses élèves vers l'histoire des relations de l'homme avec son environnement, histoire dont il fut l'un des pionniers. Il a donné en particulier une impulsion décisive à l'histoire du monde animal. De plus, en élargissant la réflexion à la fois sur le plan chronologique et géographique bien au-delà de la période médiévale et de l'Occident européen, il propose une investigation globale du devenir historique qui séduit ses auditeurs et ses lecteurs en France comme à l'étranger. Le volume des études présentement offertes à Robert Delort par ses amis et élèves, s'ouvrant sur une préface de Jacques Le Goff, veut témoigner de la globalité méthodologique, thématique, chronologique et géographique de sa pensée historique

Individual geographic mobility in a Viking-Age emporium—Burial practices and strontium isotope analyses of Ribe’s earliest inhabitants

Individual geographic mobility is a key social dynamic of early Viking-Age urbanization in Scandinavia. We present the first comprehensive geographic mobility study of Scandinavia’s earliest emporium, Ribe, which emerged around AD 700 in the North Sea region of Denmark. This article presents the results of strontium isotope analyses of 21 individuals buried at Ribe, combined with an in-depth study of the varied cultural affinities reflected by the burial practices. In order to investigate geographic mobility in early life/childhood, we sampled multiple teeth and/or petrous bone of individuals, which yielded a total of 43 strontium isotope analyses. Most individuals yielded strontium isotope values that fell within a relatively narrow range, between 87Sr/86Sr = 0.709 to 0.711. Only two individuals yielded values >87Sr/86Sr = 0.711. This suggests that most of these individuals had local origins but some had cultural affinities beyond present-day Denmark. Our results raise new questions concerning our understanding of the social and cultural dynamics behind the urbanization of Scandinavia