MOLECULAR DYNAMICS APPROACH OF THE [001] TWIST GRAIN BOUNDARIES ENERGY IN Cu

Using the Molecular Dynamics technique the energy E vs the misorientation θ has been calculated for the CSL [001] twist grain boundaries in Cu. Two potentials have been used ; the Morse potential and a spline potential constructed by Englert and Tompa for Cu. In each case the low and high angle grain boundary regions have been clearly distinguished by using the relation E=E0θ(A-lnθ), valid for low angle grain boundaries. To this relation a polynomial has been added, in order to describe the energy vs misorientation dependence in the range (0,450)

CUBIC [001] TWIST CSL GRAIN BOUNDARIES STUDY BY MEANS OF RANDOM WALK

The random walk procedure has been applied on some typical relaxed CSL twist grain boundaries. The relaxation has been achieved by means of the Molecular Dynamics method, applied on the CSL computational cells. Some of the random walk parameters are discussed and the information dimension is examined as a function of the rotation angle θ. The remarkable anisotropy observed in the parameters between the grain boundary and the bulk is common to many dynamical properties of the grain boundaries

INTERFACE JUNCTIONS AND SIMMETRY

Des jonctions triples de haute symétrie sont examinées par MET dans le silicium. Les propriétés de symétrie des grains et de leurs interfaces sont étudiées sur base du modèle de CSL. Des jonctions de flexions suivant ˂110˃ de type Σ(3,3,9), Σ(3,9,27a), et Σ(3,27a,81d) sont examinées ; elles contiennent toutes une Σ=3 avec interface {111}. La relation des interfaces avec les CSL et la symétrie des jonctions triples est analysée en details.High symmetry triple junctions in polysilicon observed by TEM are presented. The symmetry properties of their grains and interfaces are studied with the use of the CSL model. The examples concern triple junctions of ˂110˃ tilt boundaries with the CSL configurations of Σ(3,3,9), Σ(3,9,27a) and Σ(3,27a,81d). In all the cases the Σ=3 twin with interface the {111} plane is at least one of the components. The connection of the interfaces with the CSLs and the symmetry of the triple junction is analytically discussed

Pattern recognition by pentraxins

Pentraxins are a family of evolutionarily conserved pattern-recognition proteins that are made up of five identical subunits. Based on the primary structure of the subunit, the pentraxins are divided into two groups: short pentraxins and long pentraxins. C-reactive protein (CRP) and serum amyloid P-component (SAP) are the two short pentraxins. The prototype protein of the long pentraxin group is pentraxin 3 (PTX3). CRP and SAP are produced primarily in the liver while PTX3 is produced in a variery oftissues during inflammation. The main functions of short pentraxins are to recognize a variery of pathogenic agents and then to either eliminate them or neutralize their harmful effects by utilizing the complement pathways and macrophages in the host. CRP binds to modified low-densiry lipoproteins, bacterial polysaccharides, apoptotic cells, and nuclear materials. By virtue of these recognition functions, CRP participates in the resolution ofcardiovascular, infectious, and autoimmune diseases. SAP recognizes carbohydrates, nuclear substances, and amyloid fibrils and thus participates in the resolution of infectious diseases, autoimmuniry, and amyloidosis. PTX3 interacts with several ligands, including growth factors, extracellular matrix component and selected pathogens, playing a role in complement activation and facilitating pathogen recognition by phagoeytes. In addition, data in gene-targeted mice show that PTX3 is essential in female fertiliry, participating in the assembly of the cumulus oophorus extracellular matrix. PTX3 is therefore a nonredundant component ofthe humoral arm of innate immuniry as well as a tuner of inflammation. Thus, in conjunction with the other components ofinnate immuniry, the pentraxins use their pattern-recognition properry for the benefit of the host