A Setup for Preparation of Glass-Carbon Coatings on TiO2-Nb2O5 Intended for Hip Joint Prostheses

A setup for preparation of glass-carbon coatings on TiO2-Nb2O5 ceramic materials, intended for implants for surgery of hip joint prostheses, is described. The setup described consists of vacuum tight ceramic chamber; programmable high temperature furnace and a system for controlled introduction of inert gas into the chamber. The setup allows working with temperatures up to 1350 oC, controlled heating rates from 1 to 15 oC/min and chamber pressures down to 10-2 mmHg

Investigation of Titanium Hydride Produced from Titanium Waste

The work presents an original method for titanium hydride production by hydrogenation and dehydrogenation of titanium waste in a specially designed for this purpose vacuum chamber. Laboratory quantities of titanium hydride were prepared using LaNi5 hydrogen accumulator as a source of pure hydrogen. Chemical, X-ray, DTA, TG and granulometric analysis of the obtained hydride were made. The analyses carried out in the temperature range, 680-1070 К, DTA, TG and mass-spectrometry analysis allowed determining the activation energy of decomposition of the obtained TiH2 which was approximately E = -135.5 kJ/mol and the standard enthalpy of formation ΔH = -140 kJ/mol

Study of the Sintering Process of Iron Powders Coated with Nano-Hydrocarbon and the Resulting Microstructure at Temperatures up to 1200°C

The objective of the research is development and study of a new ecologically friendly and technologically advanced method for introduction of carbon during sintering of low alloyed iron powders ASC 100.29. The method is based on using hydrocarbon coating of the green powder, which transforms into carbon nanolayers between the powder particles, during the sintering process. The method avoids the use of graphite as alloying element and reductant, and allows for a much better homogenization, less porosity and overall increase of the quality of the final sintered product. The research presented is focused on the processes related to apparent density, fluidity and compressibility of the coated powder and resulting porosity after pressing and sintering. The aim is to determine the optimal coating conditions, and to acquire experimental data concerning key processes during the sintering and the originated microstructure. The sintering process was monitored in situ through DTA measurements and measurement of the exhaust gases pressure. Results obtained so far show better handling conditions for the green coated powders, compared to those using classical approach and higher homogeneity of the sintered specimens

Glass-Carbon Bioactive Coatings on a TiO2- Nb2O5 Substrate

The research carried out studies the processes of coating and impregnation of non-active glass carbon coatings on TiO2-Nb2O5 substrates, intended for surgery implants for hip joint prostheses. It was found that the coating procedure implemented and the subsequent impregnation, lead to filling of the substrate’ pores with glass carbon, thus resulting in a substantial decrease of the substrate’s roughness. It was found that preliminary treatment of the substrate aiming at a formation of TiC on its surface is important for the subsequent buildup of a stable glass-carbon coating. The tribological measurements carried out show substantial decrease of the friction coefficient of vitreous carbon (VC) – hip joint, which is the prerequisite for using these coatings as surgery implants for hip joint prostheses

Quantum transport and utilization of free energy in protein α\alpha-helices

The essential biological processes that sustain life are catalyzed by protein nano-engines, which maintain living systems in far-from-equilibrium ordered states. To investigate energetic processes in proteins, we have analyzed the system of generalized Davydov equations that govern the quantum dynamics of multiple amide I exciton quanta propagating along the hydrogen-bonded peptide groups in $\alpha$-helices. Computational simulations have confirmed the generation of moving Davydov solitons by applied pulses of amide I energy for protein $\alpha$-helices of varying length. The stability and mobility of these solitons depended on the uniformity of dipole-dipole coupling between amide I oscillators, and the isotropy of the exciton-phonon interaction. Davydov solitons were also able to quantum tunnel through massive barriers, or to quantum interfere at collision sites. The results presented here support a nontrivial role of quantum effects in biological systems that lies beyond the mechanistic support of covalent bonds as binding agents of macromolecular structures. Quantum tunneling and interference of Davydov solitons provide catalytically active macromolecular protein complexes with a physical mechanism allowing highly efficient transport, delivery, and utilization of free energy, besides the evolutionary mandate of biological order that supports the existence of such genuine quantum phenomena, and may indeed demarcate the quantum boundaries of life.Comment: 40 pages, 20 figure

Phase Transitions and Spatio-Temporal Fluctuations in Stochastic Lattice Lotka-Volterra Models

We study the general properties of stochastic two-species models for predator-prey competition and coexistence with Lotka-Volterra type interactions defined on a $d$-dimensional lattice. Introducing spatial degrees of freedom and allowing for stochastic fluctuations generically invalidates the classical, deterministic mean-field picture. Already within mean-field theory, however, spatial constraints, modeling locally limited resources, lead to the emergence of a continuous active-to-absorbing state phase transition. Field-theoretic arguments, supported by Monte Carlo simulation results, indicate that this transition, which represents an extinction threshold for the predator population, is governed by the directed percolation universality class. In the active state, where predators and prey coexist, the classical center singularities with associated population cycles are replaced by either nodes or foci. In the vicinity of the stable nodes, the system is characterized by essentially stationary localized clusters of predators in a sea of prey. Near the stable foci, however, the stochastic lattice Lotka-Volterra system displays complex, correlated spatio-temporal patterns of competing activity fronts. Correspondingly, the population densities in our numerical simulations turn out to oscillate irregularly in time, with amplitudes that tend to zero in the thermodynamic limit. Yet in finite systems these oscillatory fluctuations are quite persistent, and their features are determined by the intrinsic interaction rates rather than the initial conditions. We emphasize the robustness of this scenario with respect to various model perturbations.Comment: 19 pages, 11 figures, 2-column revtex4 format. Minor modifications. Accepted in the Journal of Statistical Physics. Movies corresponding to Figures 2 and 3 are available at http://www.phys.vt.edu/~tauber/PredatorPrey/movies

Quantum transport and utilization of free energy in protein α-helices

The essential biological processes that sustain life are catalyzed by protein nano-engines, which maintain living systems in far-from-equilibrium ordered states. To investigate energetic processes in proteins, we have analyzed the system of generalized Davydov equations that govern the quantum dynamics of multiple amide I exciton quanta propagating along the hydrogen-bonded peptide groups in α-helices. Computational simulations have confirmed the generation of moving Davydov solitons by applied pulses of amide I energy for protein α-helices of varying length. The stability and mobility of these solitons depended on the uniformity of dipole-dipole coupling between amide I oscillators, and the isotropy of the exciton-phonon interaction. Davydov solitons were also able to quantum tunnel through massive barriers, or to quantum interfere at collision sites. The results presented here support a nontrivial role of quantum effects in biological systems that lies beyond the mechanistic support of covalent bonds as binding agents of macromolecular structures. Quantum tunneling and interference of Davydov solitons provide catalytically active macromolecular protein complexes with a physical mechanism allowing highly efficient transport, delivery, and utilization of free energy, besides the evolutionary mandate of biological order that supports the existence of such genuine quantum phenomena, and may indeed demarcate the quantum boundaries of life

Positive impacts of important bird and biodiversity areas on wintering waterbirds under changing temperatures throughout Europe and North Africa

Migratory waterbirds require an effectively conserved cohesive network of wetland areas throughout their range and life-cycle. Under rapid climate change, protected area (PA) networks need to be able to accommodate climate-driven range shifts in wildlife if they are to continue to be effective in the future. Thus, we investigated geographical variation in the relationship between local temperature anomaly and the abundance of 61 waterbird species during the wintering season across Europe and North Africa during 1990-2015. We also compared the spatio-temporal effects on abundance of sites designated as PAs, Important Bird and Biodiversity Areas (IBAs), both, or neither designation (Unlisted). Waterbird abundance was positively correlated with temperature anomaly, with this pattern being strongest towards north and east Europe. Waterbird abundance was higher inside IBAs, whether they were legally protected or not. Trends in waterbird abundance were also consistently more positive inside both protected and unprotected IBAs across the whole study region, and were positive in Unlisted wetlands in southwestern Europe and North Africa. These results suggest that IBAs are important sites for wintering waterbirds, but also that populations are shifting to unprotected wetlands (some of which are IBAs). Such IBAs may therefore represent robust candidate sites to expand the network of legally protected wetlands under climate change in north-eastern Europe. These results underscore the need for monitoring to understand how the effectiveness of site networks is changing under climate change.Peer reviewe

Khresmoi Professional: Multilingual Semantic Search for Medical Professionals

There is increasing interest in and need for innovative solutions to medical search. In this paper we present the EU funded Khresmoi medical search and access system, currently in year 3 of 4 of development across 12 partners . The Khresmoi system uses a component based architecture housed in the cloud to allow for the development of several innovative applications to support target users medical information needs. The Khresmoi search systems based on this architecture have been designed to support the multilingual and multimod al information needs of three target groups the general public, general practitioners and consultant radiologists. In this paper we focus on the presentation of the systems to support the latter two groups using semantic, multilingual text and image based (including 2D and 3D radiology images) search

Сверхлегкие генераторные модули для КВЧ-терапии

Разработаны миниатюрные генераторные модули для КВЧ-терапии, лег-ко фиксируемые в любом месте тела пациента. Могут быть использованы не только в медицине