Vol 63, No 10 (2018)
- Year: 2018
- Articles: 24
- URL: https://journals.rcsi.science/1063-7842/issue/view/12584
Physical Approaches and Problems of Data Interpretation in the Life Sciences
Physical and Physiological Mechanisms of Consciousness and General Anesthesia (Review)
Abstract
General anesthesia (narcosis) is an induced, reversible inhibition of the central nervous system (CNS) with suppression of pain sensitivity, consciousness, motor, and vegetative activity during surgeries. The existing pharmacological theories provide no exhaustive explanation of the consciousness suppression mechanism, although mechanisms of other narcosis effects are well studied. The reason lies in the radical difference of the vertical construction scheme of CNS conduction pathways for organization of most of its perceptual and executive functions from the organization structures of the brain, which must be associated with processes of consciousness in information analysis and control command synthesis as a key synergetic factor of a self-organizing system. This makes it possible not only to explain the matter of phenomena of anesthesia through changing functional dynamic orderliness in the neural networks of the cerebral cortex, but also to control anesthesia depth and a patient’s condition in general with methods of self-organization analysis by informational richness of their regulation signals, monitoring fractal dimension trend of an entropy attractor generated at the same time.
Effect of Temperature on Metabolism and Lifespan in Several Homeothermic Animals
Abstract
The effects of various parameters on metabolism was analyzed in several homeothermic animals, including mammals, passerine birds, and humans. A Boltzmann equation was obtained for the basal metabolic rate, with the activation energy coinciding in magnitude with the energy of enzymatic cleavage of macroergic P–O bonds in adenosine triphosphate acid molecules. A dependence was obtained to relate the lifespan with the body temperature, body mass, basal metabolic rate, and Rubner’s constant.
Thermoelectric and Thermoelectrokinetic Phenomena in Liquid Biological Systems
Abstract
Thermoelectric and thermoelectrokinetic phenomena have been studied in liquids that could serve as analogs for biological liquids, namely, physiological (Ringer’s) solution that is isotonic to blood plasma and iron (III) hydroxide colloid solution. The thermoelectric (Seebeck) coefficient and thermoelectrokinetic coefficient have been measured. The results indicate that the above phenomena are associated with the electrical properties of bioliquids representing charged colloids and may play an essential role in them.
Development of Process Technologies, Diagnostic Methods, and Functional Materials and Structures
Bioactive Silver-Containing Compositions of Methyl Cellulose with a Natural Sorbent Zosterin: The Structure, Morphology, and Properties
Abstract
The morphology, structure, and optical properties of polymeric compositions based on a natural sorbent Zosterin, methyl cellulose (MC), and a Poviargol (silver-containing preparation) are studied via atomic force microscopy (AFM), transmission electron microscopy (TEM), dynamic light scattering (DLS), and X-ray diffraction (XRD). AFM studies show substantial changes in the morphology of the surface of obtained films from granular with different grain sizes (for Zosterin and an MC/Zosterin binary system) to spongy with nanopores and submicron pores on the surface (for an MC/Zosterin/Poviargol ternary system). Silver nanoparticles with different shapes and sizes are observed by TEM in the MC/Zosterin/Poviargol ternary system against the background of the MC/Zosterin polymer matrix which has fractal-type morphology. A reflection corresponding to zero-valent silver is found by XRD in the MC/Zosterin/Poviargol ternary composition.
Instrument Development and Devices for Practical Applications
Development of a Thermometric Glove for Monitoring the Limbs of a Person Who Has Received Cold Trauma
Abstract
In this paper, we describe a prototype for automated monitoring of the temperature of a person’s limbs. We developed a unit named “thermometric glove” for use in treatment of frostbite injuries. The thermometric glove is cable of measuring the surface temperature of a limb at several points of mounting, perform automatic recording, and store temperature values in the internal memory. Two versions of the device and the results of approbation and experimental exploitation of prototypes are present.
Simulation of Kinetic Curves of Polymerase Chain Reaction Obtained Using Fluorescent Oligonucleotide Probes
Abstract
At present, many polymerase chain reaction models have been proposed for exact quantitative estimation of the reaction results. In most models, kinetics of product accumulation and kinetics of fluorescent reporter are assumed to be identical. A model of the polymerase chain reaction is proposed to study the difference of such functions in the system in which a hybridization probe serves as the source of the detected fluorescence signal. Adequacy of the model is verified, and significant possible difference of the accumulation kinetics of product and probe reporter is demonstrated.
Theoretical and Mathematical Physics
Ellipsoidal Inclusion with a Shell in an Anisotropic Medium Subjected to a Uniform Electric Field
Abstract
An electrostatic problem has been solved for a dielectric inclusion consisting of an anisotropic core and a shell immersed in a homogeneous anisotropic dielectric medium (matrix) subjected to a uniform electric field. The outer boundaries of the core and shell are assumed to be ellipsoids, which are confocal after a linear nonorthogonal transformation that eliminates the anisotropy of the dielectric properties of the shell. Analytical expressions have been obtained for the potential and the electric field strength in the matrix, in the shell and core, and an expression for the inclusion polarizability tensor. A special case of inclusion with an isotropic shell is considered. The expressions obtained are applied to the case of an anisotropic sphere with an isotropic shell immersed in an anisotropic medium. It is also shown that in the limiting case of a homogeneous ellipsoidal inclusion in an anisotropic medium, the obtained result agrees with known solutions.
Kernels of the Direct Collision Integral of the Nonlinear Boltzmann Equation
Abstract
This paper reviews the properties of kernels of the direct collision integral describing the escape of particles from an element of the phase volume due to collisions, as well as properties of kernels of the integral operators arising in expansion of the direct collision integral in spherical harmonics. It is shown that, for isotropic scattering cross sections depending on the relative velocity by a power law, these kernels can be obtained in an analytical form. Since the analytical expressions for the kernels with large indices become too cumbersome, their asymptotics are found.
Calculation of Self-Sputtering Yield under Ion Bombardment of Solids: Computer Simulation and Theory
Abstract
We developed a computer simulation program for investigation of solid self-sputtering under ion bombardment. The program is based on binary collision approximation, truncated Coulomb potential, and the model of local inelastic losses proportional to energy. As a result of simulation, the self-sputtering yield is calculated as a function of atomic number and ion energy. To verify the cascade simulation code, we created a self-sputtering theory for the case of hard sphere potential. Simulation results show good agreement with both experimental data and theory.
Gases and Liquids
Plasma
Gas Electric Discharge with a Developed Streamer Structure in a Quasi-Optical Microwave Beam
Abstract
Experiments on initiating an electrical discharge with a developed streamer structure in atmospheric pressure air are described. The discharge was initiated in a quasi-optical linearly polarized microwave beam with a subcritical field. Air breakdown was initiated by an electromagnetic vibrator placed in free space, on the surface of a dielectric plate, and on the outer or inner surface of a quartz tube. From experimental data, the velocity of the discharge front propagation toward the wavevector of the electromagnetic wave has been estimated.
Parameters of a Microstructure of Erosion Regions during the Action of a Spark Discharge on a Copper Electrode Surface in Air
Abstract
The parameters of a microstructure of regions of action of a spark discharge on a copper plane electrode surface in air at atmospheric pressure in the spike–plane gap both for positive and negative polarity of a spike have been studied using scanning electron microscopy. It has been found that regions of action have the appearance of rounded spots or groups of spots with an internal structure in the form of agglomeration of a large number of microcraters. It has been shown that the statistical distributions of microcrater diameters and intermicrocrater distances are characterized by several local maximums that determine the presence of several predominant values of these parameters in a spot. It has been revealed that the microstructure of a spot is characterized by the fractal behavior and the fractal dimensionalities of the microstructure have been determined.
Solid State
The Simulation of Rate-Dependent Behavior of Ferroelectroelastic Materials under Cyclic Loading
Abstract
A phenomenological model of the nonlinear coupled electromechanical behavior of a polycrystalline ferroelectric piezoceramics under the complex multi-axis exposure is developed while considering sensitivity to the loading rate and is aimed at solving boundary value problems. The ability to describe creep effects and sensitivity of the hysteresis curves to the external exposure frequency is considered in the context of a single model. The predicted data are compared to the experimental results on macroscopic samples of PZT PIC 151 piezoceramic subjected to cyclic loading. The juxtaposition of theoretical data with those simulated via other models reveals better accuracy of the model proposed in the present study.
Theoretical Justification and Experimental Confirmation of the Selection Condition of Material for the Antidiffusion Layer of the Heat-Resistant Bimetallic Wire
Abstract
In this paper, we provide theoretical justification and experimental confirmation of the selection condition of material for antidiffusion layers of heat-resistant bimetallic wire used in windings of electromagnetic pumps and electric motors. The theoretical justification is formulated based on the concept of absence of adhesion between elements of the wire structure and, therefore, mutual diffusion of materials of its constituents. A model of a continuous elastic solid is adopted to quantify the condition of the material choice for the antidiffusion layer of a bimetallic wire.
Physical Science of Materials
Nanopore Evolution Kinetics during Annealing of Submicrocrystalline Materials
Abstract
The evolution kinetics of nanopores located at triple junctions has been analyzed during low-temperature annealing of submicrocrystalline materials obtained by intensive plastic deformation. The influence of elastic stresses due to strain-induced disclinations at the junctions and of grain boundary nonequilibrium on nanopore kinetics has been studied.
Solid State Electronics
Theoretical Analysis of the Effect of dU/dt in 4H–SiC Thyristor Structures
Abstract
On the basis of numerical simulation, specificities of the effect of dU/dt in 4H–SiC thyristor structures, related to realization of the recently discovered triggering α-mechanism are analyzed. It is shown that one of the manifestations of this mechanism is a catastrophic reduction in the voltage blocked by a thyristor with an increase in temperature of the structure. Practical ways of eliminating this effect are discussed.
Physics of Nanostructures
Properties of ZnSe/Al2O3 Nanostructures Obtained by RF Magnetron Sputtering
Abstract
Experimental data for the synthesis of ZnSe/Al2O3 nanostructures utilizing a technology widely used in integrated circuit (IC) production are reported. It has been shown that the refractive index and size of the coherent scattering domains grow, whereas the energy bandgap decreases, with an increase in ZnSe width. It has been supposed that samples with a ZnSe width of 9 Å contain a ZnSeO3 compound and/or ZnSe ⋅ Al2O3 complex compound. Multilayer heterostructures with a ZnSe width more than 9 Å contain cubic ZnSe nanocrystallites.
Optics
Absolutely Calibrated Spectrally Resolved Measurements of Xe Laser Plasma Radiation Intensity in the EUV Range
Abstract
With the aid of Mo/Be and Si/Mo interference mirrors, measurements of radiation intensity from laser plasma with Xe gas-jet target have been realized within a wavelength interval of 11–14 nm with a spectral resolution of 3–6 Å. The results are compared with the spectrum formerly measured with the aid of a spectrograph. The ratio of intensities at wavelengths of 11.2 and 13.5 nm has been found to be about 10 under experimental conditions studied.
Lasing in 9.6-μm Quantum Cascade Lasers
Abstract
Lasing in MBE-grown impulsively pumped quantum cascade lasers of 9.6 μm at 140 K has been demonstrated. The active area is based on three-phonon resonance scattering of electrons. An In0.53Ga0.47As/Al0.48In0.52As solid alloy heteropair was used to form periods of quantum cascade lasers. The upper In0.52Al0.48As cladding of the waveguide was made thick. Alloyed and unalloyed lower metallization systems were studied. The threshold current density for a ridge laser 1 mm long and 27 μm wide has been found to roughly equal 3 kA/cm2 at 87 K. The optical output power has been estimated at a level of 20–35 mW.
Electrophysics, Electron and Ion Beams, Physics of Accelerators
Generation of High-Intensity Aluminum-Ion Beams at Low Energy
Abstract
High-intensity repetitively pulsed beams of low-energy aluminum ions are generated in experiments. A continuous vacuum–arc discharge is used as a generator of metal plasma. Aluminum-ion beams with a current density of up to 0.47 A/cm2 are generated owing to the plasma immersion extraction of ions with subsequent ballistic focusing in the drift space of potential electrodes. Regularities of the generation of high-intensity ion beams are studied at a pulse repetition rate of 105 pulses per second versus bias voltage ranging from 1.2 to 3 kV, pulse duration ranging from 2 to 8 μs, and residual gas pressure. Transport efficiency and beam focusing are determined by the conditions for neutralization of the space charge. Even under complete filling of the drift space with preliminary injected plasma, the conditions for neutralization of space charge are dynamically varied due to an increase in the space charge upon ballistic focusing. Experimental results are presented to prove formation of a virtual anode under conditions for insufficient plasma injection in the drift space of the beam. It is shown that the transport efficiency of the high-intensity beam may substantially be increased in the presence of argon in the experimental chamber.
Physical Electronics
Atomic Layer Deposition of Thin Films onto 3D Nanostructures: The Effect of Wall Tilt Angle and Aspect Ratio of Trenches
Abstract
A theoretical model predicting the spatial profile of a film grown on walls by atomic layer deposition (ALD) is developed. The possible initial nonverticality of trench walls and the dynamic variation of the aspect ratio of the structure in the process of film growth in nanosized trenches are considered in this model. The dependence of the resulting film thickness and conformity on ALD process parameters is studied theoretically.
Biomedical Physics
Determination of a Dose Absorbed in a Biological Sample under Mixed Gamma–Neutron Irradiation
Abstract
A Hardware-Software Package for Analyzing the Gait of Patients with Normal Pressure Hydrocephalus
Abstract
This paper offers a new method for analyzing the gait of patients with normal pressure hydrocephalus, as well as several other pathological diseases accompanied by gait disorders, in particular Parkinson’s and Alzheimer’s diseases. To this end, using the ultrasonic range finder, a gressogram is recorded: the dependence of the distance traveled by the patient on time and its derivative, which is analyzed by means of the Fourier transform. The performed analysis makes it possible to determine such significant gait parameters as the total time spent for travelling a distance, the total number of steps, the average step length, the average, minimum, and maximum values of march velocity, and the average time taken per step. Comparison of gait parameters before and after the tap test makes it possible to evaluate the prospects of ventriculoperitoneal shunt surgery in a patient with normal pressure hydrocephalus, while their determination after surgery allows one to conclude its effectiveness. In the case of Parkinson’s disease, positive dynamics in gait estimation by the described method against the background of taking Levodopa will allow carrying out differential diagnostics of this disease from normal pressure hydrocephalus. This work shows that parameters such as average velocity, amplitude of spread of instantaneous velocities at the march distance, time spent per step and, as a consequence, average step length are sensitive to the condition of a patient with normal pressure hydrocephalus. An important tool for analysis, as it turned out, are rhythmograms, which make it possible to detect gait rhythm abnormalities. The developed device in combination with a set of algorithms can be used to create a hardware-software package for collecting telemetric information for express analysis of gait.
Experimental Instruments and Technique
Double-Membrane Sampling System in a Mass Spectrometer for the Study of Exhaled Air
Abstract
A double-membrane sample-introduction system is described that enables mass spectrometric determination of volatile organic compounds in air, while ensuring their detection limits are as low as a few fractions of ppb of sample composition in real time with a response delay from a few seconds to a few dozens of seconds. It includes two membrane interfaces separated by a volume, the gas pressure in which is maintained through a channel with an adjustable evacuation cross-section. The results of numerical simulation and experimental testing of the system are provided. A technique for selecting and calculating system parameters is described. The possibility of using this system for diagnosing diseases by trace amounts of biomarkers in exhaled air is discussed.