Nucleation and growth of sodium colloids in NaCl under irradiation: theory and experiment

A mechanism of radiation-induced emission of Schottky defects from extended defects proposed originally for metals has recently been applied to ionic crystals, where it is based on interactions of excitons with extended defects such as dislocations and colloids. Exciton trapping and decay at colloids may result in the emission of F centers and consequent shrinkage of the colloid. In the present paper, the radiation-induced emission of F centers is taken into account in the modeling of nucleation and growth of sodium colloids and chlorine bubbles in NaCl exposed to electron or gamma irradiation. The evolution of colloid and bubble number densities and volume fractions with increasing irradiation dose is modeled in the framework of a modified rate theory and compared with experimental data. Experimental values of the colloid volume fractions and number densities have been estimated on the basis of latent heat of melting of metallic Na obtained with combined differential scanning calorimetry experiments and atomic force microscopy investigations of metallic clusters.

RIBFIND: a web server for identifying rigid bodies in protein structures and to aid flexible fitting into cryo EM maps

Motivation: To better analyze low-resolution cryo electron microscopy maps of macromolecular assemblies, component atomic structures frequently have to be flexibly fitted into them. Reaching an optimal fit and preventing the fitting process from getting trapped in local minima can be significantly improved by identifying appropriate rigid bodies in the fitted component. Results: Here we present the RIBFIND server, a tool for identifying rigid bodies in protein structures. The server identifies rigid bodies in proteins by calculating spatial proximity between their secondary structural elements. Availability: The RIBFIND web server and its standalone program are available at http://ribfind.ismb.lon.ac.uk

Rings whose ideals are close to automorphism-invariant

We consider rings whose one-sided ideals are close to automorphism-invariant modules. We study rings in which every (finitely generated) right ideal is automorphism invariant and rings in which every right ideal is a finite direct sum of automorphism invariant ideals. Connections between these classes of rings, $q$-ring and $\Sigma$-$q$-rings are also consideredComment: arXiv admin note: substantial text overlap with arXiv:1503.0224

Rings of formal matrices close to regular

© 2015, Allerton Press, Inc. We give a description of rings of formalmatrices belonging to one of the following classes of rings: semiartinian rings, max-rings, V -rings, SV -rings. We study semiartinian SSP-rings and SSP-rings of formal matrices

Generalized SV -rings of bounded index of nilpotency

We obtain a criterion under which all right modules over a ring of bounded index are weakly regular. © 2011 Allerton Press, Inc

Generalized SV-modules

Given an arbitrary quasiprojective right R-module P, we prove that every module in the category σ(P) is weakly regular if and only if every module in σ(M/I(M)) is lifting, where M is a generating object in σ(P). In particular, we describe the rings over which every right module is weakly regular. © 2009 Pleiades Publishing, Ltd

TOPOFIT-DB, a database of protein structural alignments based on the TOPOFIT method

TOPOFIT-DB (T-DB) is a public web-based database of protein structural alignments based on the TOPOFIT method, providing a comprehensive resource for comparative analysis of protein structure families. The TOPOFIT method is based on the discovery of a saturation point on the alignment curve (topomax point) which presents an ability to objectively identify a border between common and variable parts in a protein structural family, providing additional insight into protein comparison and functional annotation. TOPOFIT also effectively detects non-sequential relations between protein structures. T-DB provides users with the convenient ability to retrieve and analyze structural neighbors for a protein; do one-to-all calculation of a user provided structure against the entire current PDB release with T-Server, and pair-wise comparison using the TOPOFIT method through the T-Pair web page. All outputs are reported in various web-based tables and graphics, with automated viewing of the structure-sequence alignments in the Friend software package for complete, detailed analysis. T-DB presents researchers with the opportunity for comprehensive studies of the variability in proteins and is publicly available at

Fully idempotent homomorphisms

For arbitrary modules A and B we introduce and study the notion of a fully idempotent Hom (A, B). As a corollary we obtain some well-known properties of fully idempotent rings and modules. © 2011 Allerton Press, Inc