Finite-element study of the customized implant for revision hip replacement

This work examines a biomechanical system consisting of the hip endoprosthesis and bones of the pelvic region of a person under a load corresponding to the equilibrium of a person in double-supported state. An assessment of the strength of a customised endoprosthesis has been carried out based on the analysis of the stress-strain state of the finite element model of the “skeleton – hip prosthesis” system when tightening the screws and when the system is subjected the person's weight; dangerous areas of the pelvic bone with high level of stresses have been identified. As recommendations, optimization of the location and number of screws used in order to create a more uniform stress distribution is proposed

Repurposing based identification of novel inhibitors against mmps5-mmpl5 efflux pump of Mycobacterium smegmatis: A combined in silico and in vitro study

In the current era of a pandemic, infections of COVID-19 and Tuberculosis (TB) enhance the detrimental effects of both diseases in suffering individuals. The resistance mechanisms evolving in Mycobacterium tuberculosis are limiting the efficiency of current therapeutic measures and pressurizing the stressed medical infrastructures. The bacterial efflux pumps enable the development of resistance against recently approved drugs such as bedaquiline and clofazimine. Consequently, the MmpS5-MmpL5 protein system was selected because of its role in efflux pumping of anti-TB drugs. The MmpS5-MmpL5 systems of Mycobacterium smegmatis were modelled and the virtual screening was performed using an ASINEX library of 5968 anti-bacterial compounds. The inhibitors with the highest binding affinities and QSAR based highest predicted inhibitory concentration were selected. The MmpS5-MmpL5 associated systems with BDE_26593610 and BDD_27860195 showed highest inhibitory parameters

Wigner phase space distribution as a wave function

We demonstrate that the Wigner function of a pure quantum state is a wave function in a specially tuned Dirac bra-ket formalism and argue that the Wigner function is in fact a probability amplitude for the quantum particle to be at a certain point of the classical phase space. Additionally, we establish that in the classical limit, the Wigner function transforms into a classical Koopman-von Neumann wave function rather than into a classical probability distribution. Since probability amplitude need not be positive, our findings provide an alternative outlook on the Wigner function's negativity.Comment: 6 pages and 2 figure

Kinematic dynamo wave in the vicinity of the solar poles

We consider a dynamo wave in the solar convective shell for the kinematic $\alpha\omega$-dynamo model. The spectrum and eigenfunctions of the corresponding equations are derived analytically with the aid of the WKB method. Our main aim here is to investigate the dynamo wave behavior in the vicinity of the solar poles. Explicit expressions for the incident and reflected waves are obtained. The reflected wave is shown to be relatively weak in comparison to the incident wave. The phase shifts and the ratio of amplitudes of the two waves are found.Comment: 20 pages, 2 EPS figure

Upper Vendian in the east, northeast and north of East European Platform: Depositional processes and bio­tic evolution

Subject. Analysis of lithogeochemical proxies in the Upper Vendian mudstones reveals little if any variation in depositional environment for the Redkinian, Belomorian and Kotlinian regional stages in the east, northeast and north of East European Platform. The coeval macrobiota, in contrast, demonstrates significant macroevolutionary and macroecological transformations. Thus, the Avalon-type ecological association consisting of frondomorphs and vendobionts evolved in low-energy inner shelf during the Redkinian, the Belomorian Stage is characterised by diversification of frondomorphs, migration of vendobionts into relatively high-energy depositional settings (shoreface and prodelta), and emergence of tribrachiomorphs and bilateralomorphs, where as the Kotlinian Stage is marked by a sharp decline in taxonomic diversity of soft-bodied organisms (the Kotlinian Crisis). We don’t know to what degree, if at all, depositional parameters as palaeogeodynamics, palaeoclimate, sediment composition, volcanic activity influenced the Ediacaran biota, but these agents were not responsible for the above mentioned biotic transformations. Materials and methods. We suggest that intrinsic factors such as ecological interactions could be the primary trigger of the Kotlinian crisis. This conclusion has been reached based on the study of composition of major rock-forming oxides, rare- and trace elements in fine-grained aluminosiliciclastic rocks (argillites, shales and silt-rich mudstones). Geological samples were collected in outcrops of the Asha Group of South Urals and Sylvitsa Group of Central Urals, as well as from the drill core of the Keltma-1 (Vychegda Trough) and Tuchkino-1000 (Southeast White Sea area) boreholes. We also used the data on chemical composition of mudstones from the Staraya Russa and Vasil’evsky Ostrov formations form the southern slope of the Baltic Shield. Results. With this information in hand we could assess, with varying degree of confidence, such parameters as a degree of recycling of the material supplied into the late Vendian Mezen Basin; sediment provenance; composition of the substrate that microbial mats and soft-bodied organisms lived on in different parts of the basin; and palaeogeodynamic environment at the time when different groups of soft-bodies organisms were emerging

Theoretical and Experimental Analysis of Structural Properties of Load-Bearing Components of Thermonuclear Tokamak Installations

The chapter presents the results of research carried out in Mechanical Engineering Research Institute of the Russian Academy of Sciences that were focused on validation and application of design diagrams, methods and systems for measuring stresses under the modes of Tokamak instillation cooling and management of electromagnetic fields during startups. The examples of tensometric systems and results of measurements of stresses under cryogenic temperatures and strong magnetic fields as well as results of analysis of the states of stresses and strains of structurally heterogeneous components of load-bearing and conductive structures are presented. Operation conditions and limit states of Tokamak components are considered. Results of research summarized in the chapter demonstrate the correctness of the adopted design solutions, which result in a relatively low level of local stresses in the load-bearing components of the thermonuclear installations

Porous Nanocrystalline Silicon Supported Bimetallic Pd-Au Catalysts: Preparation, Characterization, and Direct Hydrogen Peroxide Synthesis.

Bimetallic Pd-Au catalysts were prepared on the porous nanocrystalline silicon (PSi) for the first time. The catalysts were tested in the reaction of direct hydrogen peroxide synthesis and characterized by standard structural and chemical techniques. It was shown that the Pd-Au/PSi catalyst prepared from conventional H2[PdCl4] and H[AuCl4] precursors contains monometallic Pd and a range of different Pd-Au alloy nanoparticles over the oxidized PSi surface. The PdAu2/PSi catalyst prepared from the [Pd(NH3)4][AuCl4]2 double complex salt (DCS) single-source precursor predominantly contains bimetallic Pd-Au alloy nanoparticles. For both catalysts the surface of bimetallic nanoparticles is Pd-enriched and contains palladium in Pd0 and Pd2+ states. Among the catalysts studied, the PdAu2/PSi catalyst was the most active and selective in the direct H2O2 synthesis with H2O2 productivity of 0.5 [Formula: see text] at selectivity of 50% and H2O2 concentration of 0.023 M in 0.03 M H2SO4-methanol solution after 5 h on stream at -10°C and atmospheric pressure. This performance is due to high activity in the H2O2 synthesis reaction and low activities in the undesirable H2O2 decomposition and hydrogenation reactions. Good performance of the PdAu2/PSi catalyst was associated with the major part of Pd in the catalyst being in the form of the bimetallic Pd-Au nanoparticles. Porous silicon was concluded to be a promising catalytic support for direct hydrogen peroxide synthesis due to its inertness with respect to undesirable side reactions, high thermal stability, and conductivity, possibility of safe operation at high temperatures and pressures and a well-established manufacturing process