411 research outputs found
Two-dimensional Tissue Image Reconstruction Based on Magnetic Field Data
This paper introduces new possibilities within two-dimensional reconstruction of internal conductivity distribution. In addition to the electric field inside the given object, the injected current causes a magnetic field which can be measured either outside the object by means of a Hall probe or inside the object through magnetic resonance imaging. The Magnetic Resonance method, together with Electrical impedance tomography (MREIT), is well known as a bio-imaging modality providing cross-sectional conductivity images with a good spatial resolution from the measurements of internal magnetic flux density produced by externally injected currents. A new algorithm for the conductivity reconstruction, which utilizes the internal current information with respect to corresponding boundary conditions and the external magnetic field, was developed. A series of computer simulations has been conducted to assess the performance of the proposed algorithm within the process of estimating electrical conductivity changes in the lungs, heart, and brain tissues captured in two-dimensional piecewise homogeneous chest and head models. The reconstructed conductivity distribution using the proposed method is compared with that using a conventional method based on Electrical Impedance Tomography (EIT). The acquired experience is discussed and the direction of further research is proposed
Image Reconstruction Based on Deterministic and Heuristic Approach
The aim of this paper is to provide a survey of the recent development in new algorithms and techniques to solve the electrical impedance tomography (EIT) inverse problem. The EIT problem is nonlinear and ill-posed. The modified Newton-Raphson method with the Tikhonov regularization and the differential evolution algorithm are used to obtain high-quality reconstruction in EIT problems. Numerical results of the reconstruction based on both deterministic and heuristic methods are presented and compared. Finally, we provide recommendations of solutions of still open problems in this field
Digital security in families: the sources of information relate to the active mediation of internet safety and parental internet skills
Recommended from our members
Fatalism, Social Support and Mental Health in Four Former Soviet Cultures
Research on social support has identified differences in levels of support between cultures, but has provided only a limited explanation of the role of values or beliefs in accounting for such variations. In this paper we examine the relationship between fatalism and perceived support amongst 2672 respondents in four former Soviet States (Russia, Georgia, Ukraine and Belorussia), with participants drawn from groups of manual workers, managers, civil servants, students and the retired in these four countries. We also examine the consequences of such social support for mental health across these nations. Findings indicate a small but significant moderator effect for fatalism on the relationship between social support and mental health. These results are discussed in the context of the continuing economic and social challenges facing the citizens of these nations
Cardiac-specific Conditional Knockout of the 18-kDa Mitochondrial Translocator Protein Protects from Pressure Overload Induced Heart Failure.
Heart failure (HF) is characterized by abnormal mitochondrial calcium (Ca2+) handling, energy failure and impaired mitophagy resulting in contractile dysfunction and myocyte death. We have previously shown that the 18-kDa mitochondrial translocator protein of the outer mitochondrial membrane (TSPO) can modulate mitochondrial Ca2+ uptake. Experiments were designed to test the role of the TSPO in a murine pressure-overload model of HF induced by transverse aortic constriction (TAC). Conditional, cardiac-specific TSPO knockout (KO) mice were generated using the Cre-loxP system. TSPO-KO and wild-type (WT) mice underwent TAC for 8 weeks. TAC-induced HF significantly increased TSPO expression in WT mice, associated with a marked reduction in systolic function, mitochondrial Ca2+ uptake, complex I activity and energetics. In contrast, TSPO-KO mice undergoing TAC had preserved ejection fraction, and exhibited fewer clinical signs of HF and fibrosis. Mitochondrial Ca2+ uptake and energetics were restored in TSPO KO mice, associated with decreased ROS, improved complex I activity and preserved mitophagy. Thus, HF increases TSPO expression, while preventing this increase limits the progression of HF, preserves ATP production and decreases oxidative stress, thereby preventing metabolic failure. These findings suggest that pharmacological interventions directed at TSPO may provide novel therapeutics to prevent or treat HF
Inorganic polyphosphate (polyP) physiology Inorganic polyphosphate in cardiac myocytes: from bioenergetics to the permeability transition pore and cell survival
Abstract Inorganic polyphosphate (polyP) is a linear polymer of P i residues linked together by high-energy phosphoanhydride bonds as in ATP. PolyP is present in all living organisms ranging from bacteria to human and possibly even predating life of this planet. The length of polyP chain can vary from just a few phosphates to several thousand phosphate units long, depending on the organism and the tissue in which it is synthesized. PolyP was extensively studied in prokaryotes and unicellular eukaryotes by Kulaev's group in the Russian Academy of Sciences and by the Nobel Prize Laureate Arthur Kornberg at Stanford University. Recently, we reported that mitochondria of cardiac ventricular myocytes contain significant amounts (280 ± 60 pmol/mg of protein) of polyP with an average length of 25 P i and that polyP is involved in Ca 2 + -dependent activation of the mitochondrial permeability transition pore (mPTP). Enzymatic polyP depletion prevented Ca 2 + -induced mPTP opening during ischaemia; however, it did not affect reactive oxygen species (ROS)-mediated mPTP opening during reperfusion and even enhanced cell death in cardiac myocytes. We found that ROS generation was actually enhanced in polyP-depleted cells demonstrating that polyP protects cardiac myocytes against enhanced ROS formation. Furthermore, polyP concentration was dynamically changed during activation of the mitochondrial respiratory chain and stress conditions such as ischaemia/reperfusion (I/R) and heart failure (HF) indicating that polyP is required for the normal heart metabolism. This review discusses the current literature on the roles of polyP in cardiovascular health and disease
OPPORTUNITIES AND PROSPECTS OF DEVELOPMENT FOR THE DIGITAL ECONOMY IN THE WORLD AND THE RUSSIAN FEDERATION
Implementation of digital economy tools in the new information environment is a catalyst for innovative development of the economic environment of the state as a whole. It is obvious that not all the available opportunities and resources for the development of the digital economy have found their vectors of implementation, many of them have not been studied sufficiently and haphazardly, the existing potential and prospects have not been disclosed.Understanding of the need to develop elements of the digital economy has come to a head in the Russian economic and legal environment, as evidenced by the development and implementation of priority areas of the strategy of scientific and technological development of Russia. The mentioned problems determine the relevance of the research study of the possibilities of applying the positive foreign experience of digitalization of the economy in domestic practice. The paper provides an overview of the main categories of the digital economy, examines the features of its widespread distribution in the countries of the world, assesses the opportunities and prospects for the development of digitalization in Russia. New technologies, criteria and approaches to assessing the level of the digital economy, its institutionalization require effective regulation and management.
Changes in Mitochondrial Calcium and ROS during Ischemia-Reperfusion in Polyphosphate-Depleted Cardiomyocytes
- …