Resolving Point Defects in the Hydration Structure of Calcite (10.4) with Three-Dimensional Atomic Force Microscopy

It seems natural to assume that defects at mineral surfaces critically influence interfacial processes such as the dissolution and growth of minerals in water. The experimental verification of this claim, however, is challenging and requires real-space methods with utmost spatial resolution, such as atomic force microscopy (AFM). While defects at mineral-water interfaces have been resolved in 2D AFM images before, the perturbation of the surrounding hydration structure has not yet been analyzed experimentally. In this Letter, we demonstrate that point defects on the most stable and naturally abundant calcite (10.4) surface can be resolved using high-resolution 3D AFM-even within the fifth hydration layer. Our analysis of the hydration structure surrounding the point defect shows a perturbation of the hydration with a lateral extent of approximately one unit cell. These experimental results are corroborated by molecular dynamics simulations.Peer reviewe

A marker for the end of adolescence

AbstractBetween childhood and adulthood, we go through puberty and adolescence. While the end of puberty is defined as the point of cessation of bone growth (epiphyseal closure; girls: 16 y; boys: 17.5 y), the end of adolescence (∼19 y) is defined less clearly, by a mixture of physical, psychological, social, and mental measures [1]. One conspicuous property of adolescence is the apparently unsaturable capacity to stay up late and to sleep in. Investigating ‘chronotypes’ we observed an abrupt change in the timing of sleep at around the age of 20 and propose this change as the first biological marker of the end of adolescence

Probing properties of molecule-based interface systems: general discussion and Discussion of the Concluding Remarks

Amabilino D, Bâldea I, Batteas J, et al. Probing properties of molecule-based interface systems: general discussion and Discussion of the Concluding Remarks. Faraday Discussions. 2017;204:503-530