RESUMO
Changes in intracranial pressure (ICP) during space flight have stimulated an area of research in space medicine. It is widely speculated that elevations in ICP contribute to structural and functional ocular changes, including deterioration in vision, which is also observed during space flight. The aim of this study was to investigate changes in OP occurring as a result of ionizing radiation exposure (at doses and dose-rates relevant to solar particle event radiation). We used a large animal model, the Yucatan mini-pig, and were able to obtain measurements over a 90 day period. This is the first investigation to show long term recordings of ICP in a large animal model without an invasive craniotomy procedure. Further, this is the first investigation reporting increased ICP after radiation exposure.
RESUMO
The structures of three methyl-substituted acetoacetanilides and of an azo pigment derived from one of them are presented and discussed together with a review of related known crystal structures. By considering the position of any aromatic substituents it is possible to predict whether the simple acetoacetanilides adopt planar structures with intramolecular hydrogen bonding or twisted structures featuring intermolecular hydrogen bonding. However, we find that the same crystal engineering rules cannot be applied to the related azo pigments: this is apparently due to the presence of an sp(2) atom which facilitates the adoption of planar conformations. The thermal properties of the acetoacetanilides were measured by DSC and are discussed with reference to their crystal structures.
RESUMO
A model for red azo pigment Ca4B was characterized structurally using synchrotron radiation. This highly anisotropic ladder structure represents a new structural class in azo pigment chemistry. The picture shows that the calcium atoms coordinate in a complex manner to three azo ligands (one terdentate, one bidentate, and one monodentate) and two water molecules simultaneously.
