Predicting elastic and plastic properties of small iron polycrystals by machine learning.

Deformation of crystalline materials is an interesting example of complex system behaviour. Small samples typically exhibit a stochastic-like, irregular response to externally applied stresses, manifested as significant sample-to-sample variation in their mechanical properties. In this work we study the predictability of the sample-dependent shear moduli and yield stresses of a large set of small cube-shaped iron polycrystals generated by Voronoi tessellation, by combining molecular dynamics simulations and machine learning.

Cation interstitial diffusion in lead telluride and cadmium telluride studied by means of neural network potential based molecular dynamics simulations.

Using a recently developed approach to represent ab initio based force fields by a neural network potential, we perform molecular dynamics simulations of lead telluride and cadmium telluride crystals. In particular, we study the diffusion of a single cation interstitial in these two systems. Our simulations indicate that the interstitials migrate via two distinct mechanisms: through hops between interstitial sites and through exchanges with lattice atoms.

Spin wave interaction with topological defects.

Following our earlier gauge field theory analysis of the diffusion and interactions of classical and quantum waves with topological defects in solids (screw and edge dislocations), we present the analysis of the interaction of a classical spin wave with a screw dislocation studied within the Heisenberg ferromagnet model in which spins are located on a lattice containing dislocations. We show that the spin wave interaction with the screw dislocation shows a similarity to the Aharonov-Bohm-like deflection found previously for scattering of acoustic waves on the same type of defects.

Interleukin 3 induces histamine synthesis in the human hemopoietic system.

Recombinant human interleukin 3 (rhIL-3) induces an increase in histamine production by human bone marrow, fetal liver, and cord blood cells. This phenomenon, already significant after 3 days of incubation, is strikingly enhanced following either enrichment in immature cell subpopulations or CD8+ cell depletion. It results from an increase in histamine synthesis because of 1) the low level of histamine cell content before any incubation, 2) the parallel increase in both extra- and intracellular histamine levels in response to rhIL-3, and 3) the early IL-3-induced increase in L-histidine decarboxylase (HDC; EC 4.