Evidence for low bioavailability of dietary nanoparticulate cerium in a freshwater food chain.

Radioactive Ce in ionic (I-Ce), nano (N-Ce, 11 ± 9 nm mean primary particle size ± standard deviation) and micron-sized (M-Ce, 530 ± 440 µm) forms associated with natural and artificial diets in natural river water and synthetic freshwater were used to measure the real-time biokinetics of dietary Ce assimilation in a freshwater food chain. The model food chain consisted of microalgae (Raphidocelis subcapitata), snails (Potamopyrgus antipodarum) and prawns (Macrobrachium australiense). Pulse-chase experiments showed that 91-100 % of all forms of cerium associated with all diets and water types were eliminated from the digestive system of the snail and prawn within 24 h, with no detectable cerium assimilation.

Validation of the Child and Youth Resilience Measure (CYRM-R) in rural contexts in South Africa.

Resilience is central to young children's healthy and happy development. The Child and Youth Resilience Measure (CYRM-R) has been widely used in several countries. However, its construct validity among young children in rural South Africa has not been examined.

Investigating the Local Bonding Structure of Amorphous Zinc Tin Oxide to Elucidate the Effect of Altering the Intercation Ratio.

In this paper, the local bonding structure in amorphous zinc tin oxide (a-ZTO) is probed using a combination of XANES and EXAFS techniques at the Zn and Sn K-edges to gain insight into charge carrier generation in the material. a-ZTO is prepared using two growth methods; spray pyrolysis and magnetron sputtering. It is seen that a-ZTO grown by magnetron sputtering shows no changes in the chemical environment as the cation ratio is varied; meanwhile, XANES analysis of spray pyrolysis grown samples shows alterations to spectra likely due to the effects caused by different precursors.