Can ionic concentration changes due to mechanical deformation be responsible for the neurostimulation caused by focused ultrasound? a simulation study

Objective Ultrasound stimulation is an emerging neuromodulation technique, for which the exact mechanism of action is still unknown. Despite the number of hypotheses such as mechanosensitive ion channels and intermembrane cavitation, they fail to explain all of the observed experimental effects. Here we are investigating the ionic concentration change as a prime mechanism for the neurostimulation by the ultrasound. Approach We derive the direct analytical relationship between the mechanical deformations in the tissue and the electric boundary conditions for the cable theory equations and solve them for two types of neuronal axon models: Hodgkin-Huxley and C-fibre. We detect the activation thresholds for a variety of ultrasound stimulation cases including continuous and pulsed ultrasound and estimate the mechanical deformations required for reaching the thresholds and generating action potentials. Main results We note that the proposed mechanism strongly depends on the mechanical properties of the neural tissues, which at the moment cannot be located in literature with the required certainty. We conclude that given certain common linear assumptions, this mechanism alone cannot cause significant effects and be responsible for neurostimulation. However, we also conclude that if the lower estimation of mechanical properties of neural tissues in literature is true, or if the normal cavitation occurs during the ultrasound stimulation, the proposed mechanism can be a prime cause for the generation of action potentials. Significance The approach allows prediction and modelling of most observed experimental effects, including the probabilistic ones, without the need for any extra physical effects or additional parameters

Scientific approach to the study of the digitalization impact on the regional economy

The authors of the article test the hypothesis about the impact of digitalisation processes on the level of territories’ economic development. This hypothesis is based on the fact that in the Russian Federation digital transformation is considered as a conceptual model for improving the activities of intraregional economic units and the development of modern society, as well as a factor of economic and social breakthrough. The purpose of the study is to develop scientific and methodological support for the territories’ transformations management based on digital transformation. Systematization and generalization of methodological approaches to the assessment of digital transformation in the region have been carried out. For this purpose, a scientific approach to the design of indicators system characterizing the processes of digitalisation is proposed. To test the approach, a correlation analysis of the current state of digital development impact on the territories’ economic results was carried out. The analysis of the statistical dependence between the development and welfare level of Russian regions and the parameters of their digitalization showed a low (moderate) relationship. This means that with the current volume of funding for digital transformation and the use of information technologies, devices and special software, it is impossible to ensure the breakthrough development of regional economic systems and their production complexes

Quasi-Two-Dimensional Dynamics of Plasmas and Fluids

In the lowest order of approximation quasi-twa-dimensional dynamics of planetary atmospheres and of plasmas in a magnetic field can be described by a common convective vortex equation, the Charney and Hasegawa-Mirna (CHM) equation. In contrast to the two-dimensional Navier-Stokes equation, the CHM equation admits "shielded vortex solutions" in a homogeneous limit and linear waves ("Rossby waves" in the planetary atmosphere and "drift waves" in plasmas) in the presence of inhomogeneity. Because of these properties, the nonlinear dynamics described by the CHM equation provide rich solutions which involve turbulent, coherent and wave behaviors. Bringing in non ideal effects such as resistivity makes the plasma equation significantly different from the atmospheric equation with such new effects as instability of the drift wave driven by the resistivity and density gradient. The model equation deviates from the CHM equation and becomes coupled with Maxwell equations. This article reviews the linear and nonlinear dynamics of the quasi-two-dimensional aspect of plasmas and planetary atmosphere starting from the introduction of the ideal model equation (CHM equation) and extending into the most recent progress in plasma turbulence.U. S. Department of Energy DE-FG05-80ET-53088Ministry of Education, Science and Culture of JapanFusion Research Cente

ОСНОВНІ ТЕНДЕНЦІЙ ДЕРЖАВНОГО РЕГУЛЮВАННЯ РОЗВИТКУ АГРОПРОМИСЛОВОГО КОМПЛЕКСУ УКРАЇНИ

The role of the state in the development of the agricultural sector and the basic forms of its ensuring defined in the article. The state financial support agricultural complex of Ukraine is analyzed. The questions of state crediting of agriculture are considered.В статье определено роль государства в развитии аграрного сектора и основные формы его обеспечения. Проанализировано государственную финансовую поддержку агропромышленного комплекса Украины. Рассмотрены вопросы государственного кредитования сельского хозяйства.В статті визначено роль держави у розвитку аграрного сектора та основні форми його забезпечення. Проаналізовано державну фінансову підтримку агропромислового комплексу України. Розглянуто питання державного кредитування сільського господарства

Influence of ripening in mother solution on characteristics of magnesium-substituted calcium phosphate powders

Effect of ripening in the mother liquor on the degree of crystallinity and dispersity of mixed powders of calcium and magnesium phosphates is studied as a function of magnesium content with the elemental composition such that (Ca + Mg)/P = 2. Ripening is found to have a positive effect on crystallinity of the apatite phase of powders. Nanocrystals with lowered tendency to aggregation are formed during the ripening period, which affords the powders with specific surface area as high as 80 m2/g. The morphology of the constituent particles depends on the magnesium content. Crystallization processes are essentially completed by the 21st day of ripenin

Optimum design of hydrodynamic thrust bearings with rayleigh's pocket profiles

Optimum design problem for hydrodynamic self-aligning acting thrust bearings was considered. Based on results for rectangular region the problem for sector region was solved. As an objective function, the maximum of pressure integral over the lubricant layer surface was used and five geometrical parameters described Rayleigh's pocket shape were used as optimization variables during optimization procedure. The bearing pressure distribution was determined on the basis of the Navier-Stokes equations using the ANSYS / CFX software. Numerically the optimization problem was solved using three different methods: IOSO, SIMPLEX and pilOPT+AFilter SQP realized in two commercial optimization software IOSO and modeFRONTIER. The aim of this investigation was designing the technologically advanced profiles of thrust bearing sector microgeometry ensuring the maximum load capacity