Structure and phase stability of nanocrystalline Ce1−xLnxO2−x/2−δ (Ln = Yb, Lu) in oxidizing and reducing atmosphere

The structure and phase evolution of nanocrystalline Ce1−xLnxO2−x/2−δ (Ln = Yb, Lu, x = 0 − 1) oxides upon heating in H2 was studied for the first time. Up to 950 °C the samples were single-phase, with structure changing smoothly with x from fluorite type (F) to bixbyite type (C). For the Lu-doped samples heated at 1100 °C in the air and H2, phase separation into coexisting F- and C-type structures was observed for ~0.40 < x < ~0.70 and ~0.25 < x < ~0.70, respectively. It was found also that addition of Lu3+ and Yb3+ strongly hinders the crystallite growth of ceria during heat treatment at 800 and 950 °C in both atmospheres. Valency of Ce and Yb in Ce0.1Lu0.9O1.55−δ and Ce0.95Yb0.05O1.975−δ samples heated at 1100 °C was studied by XANES and magnetic measurements. In the former Ce was dominated by Ce4+, with small contribution of Ce3+ after heating in H2. In the latter, Yb existed exclusively as 3+ in both O2 and H2

Lanthanum Molybdate Nanoparticles from the Bradley Reaction: Factors Influencing Their Composition, Structure, and Functional Characteristics as Potential Matrixes for Luminescent Phosphors

The article reflects on the body and on the health and illness process as non-natural facts. Starting from a bibliographic review, it uses some ideas of the history of Western Medicine to contextualize body conceptions, sexual differences, and the health and illness process. In addition, it discusses other medical rationalities and religious cosmologies, in which the conceptions of body, health and illness differ from those of the Western Medicine. It employs some anthropological approaches to show the cultural modeling of the body and its uses; the symbolic dimension and its inclusion in the network of social relations and norms and also its links with the environment and the representations of the person, through ethnographic examples extracted from the literature.O artigo reflete, a partir de revisão bibliográfica, sobre o corpo e o processo saúde e doença como fatos não naturais. Vale-se de algumas ideias da história da Medicina Ocidental para contextualizar as concepções do corpo, as diferenças sexuais e a saúde e doença, assim como de outras racionalidades médicas e cosmologias religiosas onde as concepções do corpo e da saúde e doença diferem da medicina ocidental. Recorre a algumas abordagens antropológicas para mostrar a modelagem cultural do corpo e de seus usos; a dimensão simbólica e sua emersão na teia das relações e normas sociais e nas relações com o meio ambiente, assim como suas articulações com a representação da pessoa, através de exemplos etnográficos extraídos da literatura