Метод розрахунку запасу міцності виробів авіаційної техніки при циклічному навантаженні

This article considers calculation method of structural strength coefficient, that ensures the requiredserviceability. The special emphasis is placed on limiting stress evaluation when structures are subject to multi-cycleasymmetric loading. The suggested approach enables to evaluate proof strength more correctly within the designprocess.В работе рассматривается метод расчета запаса прочности элементов конструкций, обеспечивающий ихнеобходимую работоспособность. Основное внимание уделяется оценке предельных напряжений приасимметричном многоцикловом нагружении. Предложенный подход способствует более корректной оценкезапаса прочности при выполнении проектных работ.В роботі розглядається метод розрахунку запасу міцності елементів конструкцій, які забезпечують їх необхідну працездатність. Основну увагу приділено оцінці граничних напружень за асиметричного багатоциклового навантаження. Запропонований підхід сприяє більш коректній оцінці запасу міцності під час виконанняпроектних робіт

A Magnetic Resonance Realization of Decoherence-Free Quantum Computation

We report the realization, using nuclear magnetic resonance techniques, of the first quantum computer that reliably executes an algorithm in the presence of strong decoherence. The computer is based on a quantum error avoidance code that protects against a class of multiple-qubit errors. The code stores two decoherence-free logical qubits in four noisy physical qubits. The computer successfully executes Grover's search algorithm in the presence of arbitrarily strong engineered decoherence. A control computer with no decoherence protection consistently fails under the same conditions.Comment: 5 pages with 3 figures, revtex4, accepted by Physical Review Letters; v2 minor revisions to conten

Dynamics on multiple timescales in the RNA-directed RNA polymerase from the cystovirus ϕ6

The de novo initiating RNA-directed RNA polymerase (RdRP), P2, forms the central machinery in the infection cycle of the bacteriophage ϕ6 by performing the dual tasks of replication and transcription of the double-stranded RNA genome in the host cell. By measurement and quantitative analysis of multiple-quantum spin-relaxation data for the δ1 positions of Ile residues that are distributed over the 3D-fold of P2, we find that the enzyme is dynamic both on the fast (ps–ns) and slow (µs–ms) timescales. The characteristics of several motional modes including those that coincide with the catalytic timescale (500–800/s) are altered in the presence of substrate analogs and single-stranded RNA templates. These studies reveal the plasticity of this finely tuned molecular machine and represent a first step towards linking structural information available from a host of crystal structures to catalytic mechanisms and timescales obtained from the measurements of kinetics for homologous systems in solution

Allosteric fine-tuning of the conformational equilibrium poises the chaperone BiP for post-translational regulation

BiP is the only Hsp70 chaperone in the endoplasmic reticulum (ER) and similar to other Hsp70s, its activity relies on nucleotide- and substrate-controllable docking and undocking of its nucleotide-binding domain (NBD) and substrate-binding domain (SBD). However, little is known of specific features of the BiP conformational landscape that tune BiP to its unique tasks and the ER environment. We present methyl NMR analysis of the BiP chaperone cycle that reveals surprising conformational heterogeneity of ATP-bound BiP that distinguishes BiP from its bacterial homologue DnaK. This unusual poise enables gradual post-translational regulation of the BiP chaperone cycle and its chaperone activity by subtle local perturbations at SBD allosteric ‘hotspots’. In particular, BiP inactivation by AMPylation of its SBD does not disturb Hsp70 inter-domain allostery and preserves BiP structure. Instead it relies on a redistribution of the BiP conformational ensemble and stabilization the domain-docked conformation in presence of ADP and ATP

Active-Site-Directed Inhibitors of Prolyl Oligopeptidase Abolish Its Conformational Dynamics

Deciphering conformational dynamics is crucial for understanding the biological functions of proteins and for designing compounds targeting them. In particular, providing an accurate description of microsecond–millisecond motions opens the opportunity for regulating protein–protein interactions (PPIs) by modulating the dynamics of one interacting partner. Here we analyzed the conformational dynamics of prolyl oligopeptidase (POP) and the effects of active-site-directed inhibitors on the dynamics. We used an integrated structural biology approach based on NMR spectroscopy and SAXS experiments complemented by MD simulations. We found that POP is in a slow equilibrium in solution between open and closed conformations, and that inhibitors effectively abolished this equilibrium by stabilizing the enzyme in the closed conformation.This work was supported by the Institute for Research in Biomedicine, MINECO-FEDER (Bio2013-40716-R, CTQ2013-48287 and CTQ2012-32183/BQU), and the Generalitat de Catalunya (XRB and Grup Consolidat 2014SGR521). AL has received funding from the Instituto de Salud Carlos III. PB acknowledges the Agence Nationale de la Recherche (SPINHD-ANR-CHEX-2011) and the ATIP-Avenir program for financial support. FHT’s fellowship is co-funded by the INSERM and the University of Copenhagen. Technical assistance from staff at the P12 beam line (EMBL/DESY) is acknowledged.Peer ReviewedPostprint (author's final draft

Development of physical and psychological states graphs of people and their software implementation in the tasks of evacuation modelling

The purpose of the presented in the article results is to increase the realism of the people evacuation modeling in case of emergency situation. Models that exist today do not describe in detail physical and psychological states of the characters during the simulation. This article presents the results of the development of people physical and psychological states graphs in the conditions of evacuation. All graphs are presented as extended final state machines. On the basis of the developed finite state machines the description of state transitions was carried out and algorithms were built This work was carried out as part of the development of a comprehensive 3D model of the people evacuation processes of in emergency situations in particular fires. A software implementation in the Unreal Engine program of these states was performed. Examples of the behavior of characters in various psychological and physical states are also presente