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Some experimental results have indicated that hydroxyapatite (HA) and octacalcium phosphate (OCP) can form an epitaxic interface. Subsequently the OCP-HA interface has become of great biological interest in the context of mineralized tissue formation. In this work a new OCP-HA interface model based on Brown's proposed configuration [Brown (1962), Nature, 197, 1048-1050] and using the minimum interface free-energy optimization is presented. This new model is formed by half a unit cell of HA and one unit cell of OCP, as in Brown's model, but in our case [1-210] of HA is 'glued' with [010] of OCP. Therefore, the relationship found was: [000-1](HA) parallel to [001](OCP) and [1-210](HA) parallel to [010](OCP). Self-consistent field methods were used for the analysis of Brown's model and ours. It is shown that the atoms in our model have similar environments as in the HA and OCP unit cells and that, as a result of the differences between HA and OCP unit-cell parameters, this interface presents misfit-dislocation-like features. High-resolution transmission electron microscopy (HREM) simulated images for the new interface model have been included and, when they are compared with the experimental ones, the similarity is quite good.

Spallation reactions on fissile nuclei represent an appropriate tool to investigate dissipative effects in nuclear fission. In this work, we have studied transient and dissipative effects in proton-and deuteron-induced fission on 208 Pb at 500A MeV. A dedicated experimental setup optimized for inverse kinematics measurements made it possible to identify in atomic number both fission fragments with high resolution, and reconstruct the charge of the fissioning system. We could then determine the width of the fission fragments charge distribution as well as partial fission cross sections, both as a function of the charge of the fissioning system. These two complementary observables permitted us to investigate the dynamics of the process at small deformation, i.e., from the ground state to the saddle point. The description of these observables with advanced model calculations reveals the influence of the nuclear dissipation in the fission process at high excitation energy and in particular its manifestation through transient time effects.

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