Some Molecular and Cellular Stress Mechanisms Associated with Neurodegenerative Diseases and Atherosclerosis

Chronic stress is a combination of nonspecific adaptive reactions of the body to the influence of various adverse stress factors which disrupt its homeostasis, and it is also a corresponding state of the organism’s nervous system (or the body in general). We hypothesized that chronic stress may be one of the causes occurence of several molecular and cellular types of stress. We analyzed literary sources and considered most of these types of stress in our review article. We examined genes and mutations of nuclear and mitochondrial genomes and also molecular variants which lead to various types of stress. The end result of chronic stress can be metabolic disturbance in humans and animals, leading to accumulation of reactive oxygen species (ROS), oxidative stress, energy deficiency in cells (due to a decrease in ATP synthesis) and mitochondrial dysfunction. These changes can last for the lifetime and lead to severe pathologies, including neurodegenerative diseases and atherosclerosis. The analysis of literature allowed us to conclude that under the influence of chronic stress, metabolism in the human body can be disrupted, mutations of the mitochondrial and nuclear genome and dysfunction of cells and their compartments can occur. As a result of these processes, oxidative, genotoxic, and cellular stress can occur. Therefore, chronic stress can be one of the causes forthe occurrence and development of neurodegenerative diseases and atherosclerosis. In particular, chronic stress can play a large role in the occurrence and development of oxidative, genotoxic, and cellular types of stress.     

Enhanced backscattering: the universal wave phenomenon

Backscattering enhancement is discussed as a universal wave phenomenon inherent to waves of whatever physical nature: electromagnetic, acoustic, spin, etc. This phenomenon arises due to multichannel wave propagation from a source to a scatterer and back and may be observed in the vicinity of the source because of mutual coherence of waves passing in opposite directions along identical (coherent) channels. Backscattering enhancement may be revealed when the wave field is scattered: by a system of chaotically distributed scatterers or by a system of inhomogeneities; by a body embedded in a turbulent medium; by a single body placed near an interface or within a waveguide (randomness of body position is assumed); by a body of complex form or a system of several scatterers randomly oriented in space; by a rough surface; and by many other physical systems. Possible practical applications of these effects are analyzed     

Combinatorial properties of noninteger vertices of a polytope in a three-index axial assignment problem

It is proved that, for any r ∈ { 2n, 2n + 1,…, 3n−2} and only for such r, the polytope of a three-index axial assignment problem of order n, n ≥ 2, contains completely r-noninteger vertices (r-CNVs), i.e., vertices such that all their positive components are fractional and their number equals r. For each r ∈ {2n, 2n + 1,…, 3n −2}, all the types of r-CNVs are characterized and the combinatorial properties of completely r-noninteger vertices of the polytope are studied. __________ Translated from Kibernetika i Sistemnyi Analiz, No. 1, pp. 33–44, January–February 2007.     

Optical amplification in a planar multichannel Mach-Zehnder interferometer based on metal-semiconductor-metal structures

This paper describes a new optoelectronic device—an optical transistor that provides power amplification of output visible radiation. The optical transistor is structurally based on a metallized semiconductor plate with a microchannel gap in the form of a planar Mach-Zehnder interferometer. A device of the light-light type is controlled by modulating the refractive index in one arm of the interferometer. Pis’ma Zh. Tekh. Fiz. 24, 17–21 (January 26, 1998)     

Production and use of periclase-chromite concrete parts for the linings of high temperature ladles

Conclusions A method has been developed for production of standard periclase-chromite concrete parts for the linings of high temperature ladles for teeming steel and ferroalloys. The parts have high strength and low porosity and are practically shrinkage-free.The life of periclase-chromite concrete parts in the steel teeming ladles of Chelyabinsk Metallurgical Plant is about four times greater than that of fireclay parts, in Red October Plant practically the same as that observed with the use of high alumina parts, and at Chelyabinsk Electrometallurgical Plant it was higher only in the upper portion of ladles in comparison with that obtained with the normally used fired periclase parts.During service in ladles the parts do not spall, become encrusted at a metal temperature of 1620 °C, do not become encrusted at 1790°C, and at 2200°C are eroded by slag.Translated from Ogneupory, No. 7, pp. 16–20, July, 1982.     

Electrochemical cell current requirements for toxic organic waste destruction in Ce(IV)-mediated electrochemical oxidation process

The electrochemical cell for cerium oxidation and reactor for organic destruction are the most important operation units for the successful working mediated electrochemical oxidation (MEO) process. In this study, electrochemical cells with DSA electrodes of two types, single stack and double stack connected in series, were used. The performances towards the electrochemical generation of Ce(IV) in nitric acid media at 80 °C were studied. The current-voltage curves and cerium electrolysis kinetics showed the dependence on number of cell stacks needed to be connected in series for the destruction of a given quantity of organic pollutant. The presence of an optimum region for Ce(III) oxidation with a contribution of oxygen evolution, especially at low Ce(III) concentration (high conversion ratios), was found. The cells were applied for the Ce(IV) regeneration during the organic destruction. The cell and reactor processes were fitted in a simple model proposed and used to calculate the current needed in terms of Ce(III) oxidation rate and the number of cell stacks required for maintaining Ce(IV)/Ce(III) ratio at the same level during the organic destruction. This consideration was based on the kinetic model previously developed by us for the organic destruction in the MEO process.     

The Multimeter at the Nanoscale

A multi‐tip scanning tunneling microscope (STM) specifically designed for charge transport measurements at the nanoscale is described. Complementing the instrument with a versatile measurement electronics creates a powerful tool to give insight into fundamental transport properties at the nanoscale. We demonstrate the capabilities of the instrument by measuring resistance profiles along freestanding GaAs nanowires, by the acquisition of nanoscale potential maps, and by the identification of an anisotropy in the surface conductivity at a silicon surface.     

Assurance of uniformity of measurements of spectral and dispersion characteristics in fiber-optic information transmission systems with wavelength-division multiplexing

The state and problems involved in achieving the uniformity of measurements in the field of fiber-optic information transmission systems and their components are considered. Possible approaches to the solution of these problems and the basic methods and techniques that have been developed in Russia up to this point are analyzed. __________ Translated from Izmeritel’naya Tekhnika, No. 5, pp. 30–34, May, 2006.     

Optimizing the catalyst circulation ratio in a reformer with a moving bed via a combination of real and computational experiments

During the operation of continuous catalyst regeneration reformers, the problem of optimizing the catalyst circulation ratio in the reactor-regenerator system arises. This problem is solved by a combination of real and computational experiments to investigate the regularities of coking on a catalyst’s surface. Based on TGA results for industrial Pt-Sn/γ-Al₂O₃ catalyst, it is concluded that amorphous coke is formed on the catalyst’s surface during reforming, its quantity at the reactor block outlet being 4–6%, depending on the feed composition and technological parameters of the process. The specific surface of samples is 152 m²/g for the fresh catalyst, 140 m²/g after regeneration, and 118 m²/g at the reactor outlet, which correlates with the quantity of coke on the surface of samples. Mathematical analysis of the coking processes in a reformer with a moving bed show that the catalyst circulation ratio must be maintained in the range of 0.008–0.010 m³/m³ to increase the operating efficiency of an industrial unit. Maintaining optimal conditions enables us to control the coking process, keeping coke concentration as low as possible and the catalyst specific surface as high as possible.     

Crystal structure and physical properties of YbCuZnSb2

The crystal structure of YbCuZnSb₂ has been determined for the first time by single-crystal X-ray diffraction analysis. It is shown that YbCuZnSb₂ has a CaAl₂Si₂-type structure, space group is P-3m1, with the following unit cell parameters: a = 4.4394(1) and c = 7.4139(3) Å. Magnetic susceptibility measurements performed in the temperature range from 2 to 300 K show that ytterbium ions are found in a nonmagnetic 4f ¹⁴ ground state (Yb²⁺). YbCuZnSb₂ exhibits p-type conductivity. The temperature dependence of the resistivity has a metallic character. The variations in the Cu/Zn ratio in the synthesized material occur without any disturbance of the structural type. This fact may confirm the existence of a solid solution between the YbZn₂Sb₂ and YbCuZnSb₂ compounds.