Identifying the Azobenzene/Aniline reaction intermediate on TiO2-(110) : a DFT Study

Density functional theory (DFT) calculations, both with and without dispersion corrections, have been performed to investigate the nature of the common surface reaction intermediate that has been shown to exist on TiO2(110) as a result of exposure to either azobenzene (C6H5N═NC6H5) or aniline (C6H5NH2). Our results confirm the results of a previous DFT study that dissociation of azobenzene into two adsorbed phenyl imide (C6H5N) fragments, as was originally proposed, is not energetically favorable. We also find that deprotonation of aniline to produce this surface species is even more strongly energetically disfavored. A range of alternative surface species has been considered, and while dissociation of azobenzene to form surface C6H4NH species is energetically favored, the same surface species cannot form from adsorbed aniline. On the contrary, adsorbed aniline is much the most stable surface species. Comparisons with experimental determinations of the local adsorption site, the Ti–N bond length, the molecular orientation, and the associated C 1s and N 1s photoelectron core level shifts are all consistent with the DFT results for adsorbed aniline and are inconsistent with other adsorbed species considered. Possible mechanisms for the hydrogenation of azobenzene required to produce this surface species are discussed

Birthing, corporality and care among the Guarani Mbyá of southern Brazil

In this paper I draw attention to the happening of childbirth among the Guarani-Mbyá women. I highlight the centrality of a care language in the act of birth and of being born supported by the production of human bodies and kin. From Yva deliveries’ stories I explore the connection between silences, bodies and human and non-human socialities by interweaving it with native modes of care and a critical analysis of the medicalization of birth derived from the relationship with the “Juruá (“white”) system”. I emphasize a non-reductive understanding of life and health in the translation of epistelomogies of care between indigenous and biomedical sociocosmologies. The data presented are results from a long-term ethnographic research carried out among guarani-mbyá collectives of the southern Brazil

Imazaquin sorption in surface and subsurface soil samples.

The objective of this work was to study the sorption and desorption of imazaquin, in surface and subsurface soil samples from Brazil. Sorption and desorption steps were carried out using batch equilibration and high performance liquid chromatography analytical routines. The value of Kf,ads was positively correlated with clay content, and negatively correlated with pH of supernatant. Samples from Typic Haplustox, clayey soil profile having high clay content, provided higher Kf,ads values, and negative correlation with organic carbon, silt content, cation exchange capacity and pH