Contribution of trans -aconitic acid to DPPH scavenging ability in different media

The antioxidant properties of trans-aconitic acid (TAA) alone or in the presence of usual antioxidants were assessed by DPPH assay. The IC50 value equal to 70mM was very high compared to usual antioxidants (vitamin C and trolox). A joint experimental/theoretical study suggested that hydrogen atom abstraction in TAA by DPPH was located on –CH2– methylene bridge because the corresponding radical was more stabilized than COO· and CC· radicals. In combination with antioxidants (vitamin C, gallic acid, caffeic acid, trolox), synergy or additivity effects were noticed. The magnitude of the synergistic effect varied between 1.06 and 1.24 depending on the type and concentration of antioxidant for a concentration of TAA equal to 22.3mM. Especially, the addition of TAA at a concentration below 32mM to a solution containing 20μM of vitamin C had a synergy effect. Beyond this concentration, TAA showed an additive effect

Des données urbaines

Le Dossier s’intéresse à la fabrique de données urbaines et à leurs usages pour analyser les conditions numériques de la transformation de la ville. Les Notes de recherche portent sur le pétitionnement en ligne, l’identité, la désinformation et la polarisation idéologique sur Facebook, l’économie des images dans un parc à thème hollywoodien et la place des blogs dans l’économie vitivinicole. La rubrique En VO questionne le rôle de Facebook dans la communication des partis politiques. Deux Focus proposent une lecture approfondie d’une œuvre récente – L’Ère du clash de Christian Salmon – et d’une œuvre plus ancienne – The Fall of the Public Man de Richard Sennett. Les Notes de lecture recensent 50 publications. The Issue explores the city in a digital context. He questions the production of data and their uses (representations, interpretations, circulations, ethics, knowledge statuses) by “doers” and researchers to analyze the digital conditions of the urban transformation. The five Research Notes cover online petitioning, identity through the case of the writer Max Jacob, disinformation and ideological polarization on Facebook, the economics of images in a Hollywood theme park and the place of the blogs in the economy of the wine sector. The section In Original Version examines Facebook’s role in the communication of political parties. Two Focus provide an in-depth reading of a recent work by Christian Salmon – L’Ère du clash – and of an older one by Richard Sennett – The Fall of the Public Man. The Book Reviews offer succinct overviews and analyses of 50 publications