Distribution of Grain Boundaries in SrTiO3 as a Function of Five Macroscopic Parameters

Measurements of the grain boundary population as a function of misorientation and boundary plane orientation show that the distribution is inversely correlated to the sum of the energies of the surfaces comprising each boundary. The observed correlation suggests that the difference between the energy of a high-angle grain boundary and the two component surfaces is relatively constant as a function of misorientation. Two exceptions to this correlation were identified: low-misorientation-angle boundaries and the coherent twin boundary, where the (111) planes in the adjoining crystals are parallel to each other, but rotated by 60° around the [111] axis. In these cases, the high degree of coincidence across this interface probably lowers the boundary energy with respect to that of the component surfaces. For all other boundaries, the anisotropy of the population is accurately predicted by the surface energy anisotropy, and in general, boundaries display a preference for {100} orientations, the planes of minimum surface energy.     

Radioimmunoassay of serum bile acid levels in biopsy-proved cirrhosis

Serum bile acid levels were determined by a radioimmunoassay for conjugates of cholic acid in 18 patients with biopsy-proved cirrhosis and compared to results of conventional liver function tests. Serum bile acid levels were abnormal in all 18 patients whereas results of the other tests were abnormal in only 50% to 72% of patients. In this group of patients with a well established diagnosis of cirrhosis, serum bile acid levels were a more sensitive indicator of liver dysfunction than standard liver function tests.     

Habits of Grains in Dense Polycrystalline Solids

We show here that the boundaries of individual grains in dense polycrystals prefer certain crystallographic habit planes, almost as if they were independent of the neighboring crystals. In MgO, SrTiO₃, MgAl₂O₄, TiO₂, and aluminum, the specific habit planes within the polycrystal correspond to the same planes that dominate the external growth forms and equilibrium shapes of isolated crystals of the same phase. The observations decrease the apparent complexity of interfacial networks and suggest that the mechanisms of solid-state grain growth may be analogous to conventional crystal growth. The results also indicate that a model for grain-boundary energy and structure based on grain surface relationships is more appropriate than the widely accepted models based on lattice orientation relationships.