Numerical study of the effect of methemoglobin concentration in the blood on the absorption of light by human skin

Lasers are widely used in dermatology to remove telangiectasias. Increasing the efficiency of sclerosis of deep-lying and large telangiectasias with laser radiation is possible by changing the optical transmission of the skin when it is heated and converting the hemoglobin of the blood contained in it into methemoglobin. The influence of the concentration of methemoglobin in the blood on the absorption of light in human skin is poorly understood, which determines the relevance of this study in the context of finding ways to improve the efficiency of laser removal of telangiectasias. Seven-layer optical models of human skin without telangiectasia and with it for numerical simulation were developed. The extinction coefficients and the degree of change in the optical transmission of whole blood and skin layers were calculated in the range of wavelength from 400 to 1600 nm for skin model without and with arteriolar and venular telangiectasias at various concentrations of methemoglobin in the blood. Based on the analysis of these data, the wavelengths with the biggest change in the optical transmission of whole blood and skin layers occurred during the transformation of hemoglobin to methemoglobin were selected. At the selected wavelengths, the Monte Carlo method was used in optical modelling to get the distribution of the absorbed optical power in each layer of the skin model without and with telangiectasia at various concentrations of methemoglobin. It has been shown that the spectra of extinction coefficients for arteriolar and venular telangiectasias do not differ significantly. During the transformation of hemoglobin to methemoglobin, the largest decrease in the degree of change in the optical transmission of whole blood occurs at wavelengths of 629 nm and 1105 nm, and the largest increase occurs at wavelengths of 447 nm and 578 nm. The part of absorbed optical power in the layer of superficial vascular plexus without and with telangiectasia at wavelengths of 629 nm and 1105 nm increases, and at wavelengths of 441 nm and 574 nm it decreases with a growth of the methemoglobin concentration from 0 to 100 % in the skin model. At the same time, in the layer of deep vascular plexus the value of part of absorbed optical power increases at wavelengths of 441 nm, 574 nm and 1105 nm, but at a wavelength of 629 nm first increases with a growth of the methemoglobin concentration up to 25 %, and then decreases, but to values exceeding the value of part of absorbed optical power without methemoglobin. The change in optical transmission associated with the replacement of blood hemoglobin with methemoglobin is more pronounced for the superficial vascular plexus layer, which is associated with high blood content in it and a limited contribution of the overlying skin layers to the deformation of the spectrum of light incident on this layer. In skin with telangiectasia, a change in the concentration of methemoglobin changes the proportion of absorbed optical power by a greater amount than in skin without telangiectasia, which can be associated with an increase in the volume concentration of blood in skin layers with telangiectasia and an increase in their thickness. The obtained results can be applied in the development of laser systems and technologies for the treatment of skin diseases, including laser sclerosis of telangiectasias

Possible connection of electric field variations with the size of ice parti- cles in the polar stratosphere

Abstract. The hypothesis is proposed that ice particles of polar stratospheric clouds (PSCs) are charged and trapped by the Earth's electric field. This hypothesis explains the absence or the lowest vertical transport of chlorine species and allows the assumption of the essential dependence of the sizes of ice particles on the magnitude of the Earth's electric field in the stratosphere. This assumption means that the ozone content in the stratosphere is closely connected to variations in the magnitude of the electric field. This conclusion is justified by experimental observations. This is the e-book version of the article, published in the Russian Journal of Earth Science

Possible connection of electric field variations with the size of ice particles in the polar stratosphere

The hypothesis is proposed that ice particles of polar stratospheric clouds (PSCs) are charged and trapped by the Earth's electric field. This hypothesis explains the absence or the lowest vertical transport of chlorine species and allows the assumption of the essential dependence of the sizes of ice particles on the magnitude of the Earth's electric field in the stratosphere. This assumption means that the ozone content in the stratosphere is closely connected to variations in the magnitude of the electric field. This conclusion is justified by experimental observations. KEYWORDS: Ozone; polar stratospheric clouds; Earth's electric field. Citation: Belikov, Yu. E. and S. Sh. Nikolaishvili (2012), Possible connection of electric field variations with the size of ice particles in the polar stratosphere, Russ

Ab Initio Calculations of the Walls Shear Strength of Carbon Nanotubes

The dependence of the energy of interwall interaction in double-walled carbon nanotubes (DWNT) on the relative position of walls has been calculated using the density functional method. This dependence is used to evaluate forces that are necessary for the relative telescopic motion of walls and to calculate the shear strength of DWNT for the relative sliding of walls along the nanotube axis and for their relative rotation about this axis. The possibility of experimental verification of the obtained results is discussed.Comment: 4 pages, 1 figur

The future of the world economy is an integrated world economic structure

Global changes in the modern world cannot be adequately described on the basis of neoliberal thinking and require a new approach. It can be formed on the basis of the cyclical-wave characterization of the development of mankind. The hypothesis about the wave-like development of the world economy with a certain cyclicity lies at the heart of thisresearch. The authors determined the economic basis of the formation, development and change of these waves (technological ways and technical revolutions). These changes reflect in the cyclical fluctuations of the world economy.The mechanism of these fluctuations is described by the theory of "large cycles of the economic conjuncture" by N. Kondratiev. The authors propose a methodology and methodological tools for analyzing and forecasting cyclic-wave processes in the economic development. The study has concluded that it is the regularities of K-cycles that allow one to correctly assess the ongoing processes in the world economy, to forecast possible variants of their development. The authors came to the conclusion that the development of the world economic structure is necessarily accompanied by a cyclical shift in the instruments of capital accumulation (material and financial expansion). These processes are reflected in the periodic replacement of scientific paradigms of economic development and management. The state always takes an active part in the phase of the dominance of productive capital, and the ideological paradigm is of a directing nature. While in the phase of domination of financial capital the liberal paradigm becomes dominant. We have substantiated the thesis about the transition from the American to the Asian systemic cycle of capital accumulation, which would inevitably lead in the middle of the 21st century to the shift of the center of the world economy from the West to the East. The paper concludes that the world is facing a change from the Monopolistic world economic structure to the Integrated world economic structure. The authors formulated the main contradiction of our present day - the confrontation of the dying Industrial Civilization in the face of the cumulative West and the emerging Information Society. The authors analyzed the main tendencies, problems and possible alternatives to the development of the world economy. It can ensure the development and adoption of political decisions for the most painless transition of Russia to the emerging forms and institutions of the global economy. © 2018 Institute of Economics, Ural Branch of the Russian Academy of Sciences. All rights reserved.The article has been prepared with the support by the Russian Foundation for Basic Research, the research project No. 18-010-00500)

Nanomechanical Properties and Phase Transitions in a Double-Walled (5,5)@(10,10) Carbon Nanotube: ab initio Calculations

The structure and elastic properties of (5,5) and (10,10) nanotubes, as well as barriers for relative rotation of the walls and their relative sliding along the axis in a double-walled (5,5)@(10,10) carbon nanotube, are calculated using the density functional method. The results of these calculations are the basis for estimating the following physical quantities: shear strengths and diffusion coefficients for relative sliding along the axis and rotation of the walls, as well as frequencies of relative rotational and translational oscillations of the walls. The commensurability-incommensurability phase transition is analyzed. The length of the incommensurability defect is estimated on the basis of ab initio calculations. It is proposed that (5,5)@(10,10) double-walled carbon nanotube be used as a plain bearing. The possibility of experimental verification of the results is discussed.Comment: 14 page

Distinguishing Dark Matter Annihilation Enhancement Scenarios via Halo Shapes

Sommerfeld enhancement and Breit-Wigner enhancement of the dark matter annihilation have been proposed to explain the "boost factor" which is suggested by observed cosmic ray excesses. Although these two scenarios can provide almost indistinguishable effects on the cosmic ray fluxes, the cross sections of the self-interaction in those enhancement mechanisms are drastically different. As a result, we show that they can be distinguished by examining the effects of the self-interaction on the halo shapes. In Sommerfeld enhancement models with m_phi<100MeV and m_DM<3TeV, the self-interaction can leave observable imprints in the galactic dynamics, while dark matter is effectively collisionless in Breit-Wigner models.Comment: 4 pages, 1 figur