This PDF file contains the front matter associated with SPIE Proceedings Volume 10337, including the Title Page, Copyright information, Table of Contents, Introduction (if any), and Conference Committee listing.

Nonlinear optic response and charge carrier kinetics in a chalcogenide glass sample of the composition As₄₀Se₃₀S₃₀ has been investigated by using the a pump – probe method. Illumination of the sample near its fundamental absorption band edge has allowed to reveal a role of gap states in the charge carriers kinetics.

We develop a microscopic theory of a strong electromagnetic radiation interaction with bilayer graphene where an energy gap is opened by a static electric field perpendicular to graphene planes. We show that an adiabatic changing on time of the gate potentials (that leads to the resonance of the energy gap with electromagnetic field) may produce full inversion of the electron population between valence and conduction bands. Quantum kinetic equations for density matrix are obtained by the use of a tight-binding approach within second quantized Hamiltonian in an intense laser field and taking into account Coulomb correlations between particles.

Excitonic absorption in graphene systems (monolayer and bilayer) with opened energy gap is investigated for different values of the gap and the parameters describing the band structure.

Dynamics of an optoelectronic oscillator have been studied. The main stable dynamical regimes have been established. Evolution of the phase portrait of the system was studied as well. Bifurcation analysis has been carried out to substantiate observed evolution of the phase space structure. It is shown that the system is multistable. Multistability is formed by combinations of periodic and quasi-periodic regimes.

Presently laser radiation is widely used in the variety of fields. This indicates the necessity of the control the intensity of laser radiation. In this case use the sensors - devices that convert laser radiation into an electronic signal. Using carbon nanotubes (CNTs) in sensor design is perspective direction, which can lead to of creating devices with impressive parameters.

Electromagnetic radiation in the complex cavity with anisotropic hyperbolic metamaterial are investigated using direct calculation of modal field and dispersion equation. Anisotropy of the hyperbolic media slab was taken into account. The 4x4 Berreman matrix method was adopted for arbitrary orientation of optical axis according to slab boundary.

The phenomenon of electron tunnel photoemission from the DLC film structure is discussed. Planar multi-electrode structure provides formation of zones of localization the electrostatic field of a certain topology. Under the influence of a strong electrostatic field, both equilibrium and nonequilibrium (photoexcited or "hot") electrons tunnel into the vacuum from the zone of concentration of electrostatic field. The results of experimental studies and theoretical simulations of the process show the saturation of photoemission current component with an increase in operating voltage. This fact makes it possible to realize the high-speed control of the spectral sensitivity of the photosensor. This is fundamentally important for applications in the modern electronic and photonic devices.

Multiple factors and their impact on the stability of DLC field emission structures are discussed in the present work. Planar multi-electrode structures, in which the formation of zones of localization the electrostatic field of a certain topology performed, are examined. Estimates carried out demonstrated the existence of an effective solution for creating reliable and durable vacuum devices for electronics and photonics. Conclusions are confirmed by the results of experimental studies. Samples of devices showed an average current density of field emission 0.30-0.35 A/cm².

In this paper the results of computer simulations of the optical reflection spectra of the structures with surface plasmons excited at the interface between metal and dielectric with optical amplification are presented. To calculate the reflectance the method of scattering matrices was used. It is shown that the enhanced reflectance from an amplifying heterogeneous metal-dielectric medium with simultaneous surface plasmon excitation is possible.

An exact solution of the problem of two two-level atoms with degenerate Raman two-photon transitions interacting with one-mode coherent or thermal radiation field in cavity is presented. Asymptotic solution for system state vector is obtained in the approximation of large initial coherent fields. The atom-field is investigated on the basis of the reduced atomic entropy dynamics. The possibility of the system being initially in a pure disentangled state to revive into this state during the evolution process is shown. Conditions and times of disentanglement are derived. The atom-atom entanglement is investigated with using negativity. The possibility of sudden death and birth of atom-atom entanglement is predicted for a coherent field with large mean photon numbers.

In this paper we study the quantum entanglement of two identical qubits which interact with electromagnetic field and each other by time-dependent dipole-dipole interaction. We develop original method in path integral approach for numerical calculation of density matrix and Peres-Horodecki parameter (the measure of qubits entanglement). By the use of obtained equations we investigate the dependence of quantum entanglement on dipole-dipole interaction amplitude and frequency as well as qubits phase difference. The results indicate on possibility of high-entanglement states exiting and long-time non-destructive control of them.

The entanglement between two identical two-level atoms successively passing the thermal cavity has been investigated taking into account the detuning. The case when atoms are initially prepared in the Bell types entangled atomic states has been considered. It has been shown that for vacuum state of the cavity the presence of detuning leads to decreasing of the entanglement amplitude oscillations. We have also derived that for thermal field the increasing of the mean photon number leads to decreasing of the entanglement, but the entanglement increases as the detuning increases. For thermal field and small detuning we have established that the effect of sudden death and birth of entanglement takes place and that for large detuning such effect vanishes.

In this paper, we have investigated the entanglement dynamics between two initially entangled superconducting qubits in the framework of a double Jaynes-Cummings model with different atom-filed coupling constants and detunings taking into account the direct dipole-dipole interaction. We have carried out the dependence of the atom-atom entanglement on the strength of the dipole-dipole interaction and other parameters of the considered system such as the different coupling constants and the detunings. The results show these parameters have great impact on the amplitude and the period of the atom-atom entanglement evolution. In addition, the presence of sufficiently large dipole-dipole interaction leads to stabilization of entanglement for all Bell-types initial qubits states and different couplings and detunings.

Method of dynamical groups and approach of coherent states have used to calculate the squeezing and multiphoton correlations in spontaneous parametric down-conversion processes. Special case of twisted photons with orbital angular momentum is considered.

We investigated numerically the time-dependent behavior of atoms populations and mean number of photons in cavities with losses. To derive the dynamic equations, we used the method of oscillator and atomic coherent states. We also took into account the various locations of the atoms in the cavity and their movement through the cavity. The losses of photons in the cavities were considered in the Wigner-Weisskopf approximation.

In the paper we construct a method for approximate solution of the waveguide problem for guided modes of an open irregular waveguide transition. The method is based on straightening of the curved waveguide boundaries by introducing new variables and applying the Kantorovich method to the problem formulated in the new variables to get a system of ordinary second-order differential equations. In the method, the boundary conditions are formulated by analogy with the partial radiation conditions in the similar problem for closed waveguide transitions.

The method is implemented in the symbolic-numeric form using the Maple computer algebra system. The coefficient matrices of the system of differential equations and boundary conditions are calculated symbolically, and then the obtained boundary-value problem is solved numerically using the finite difference method. The chosen coordinate functions of Kantorovich expansions provide good conditionality of the coefficient matrices. The numerical experiment simulating the propagation of guided modes in the open waveguide transition confirms the validity of the method proposed to solve the problem.

We investigate the waveguide propagation of polarized monochromatic light in a smoothly irregular transition between two regular planar dielectric waveguides. The single-mode approximation of the cross-sections method is used. The smooth evolution of the electromagnetic field propagating mode is calculated. The calculation is performed using the regularized stable numerical method.

The paper describes the classical and generalized Luneburg lens in the 3D and planar waveguide implementation. We demonstrate the relation between the focusing inhomogeneity of the effective refractive index of waveguide Luneburg lens and the irregularity of the waveguide layer thickness generating this inhomogeneity. For the dispersion relation of the irregular thin-film waveguide in the model of adiabatic waveguide modes we solve the problem of mathematical synthesis and computer-aided design of the thickness profile of waveguide layer for the Luneburg thin-film generalized waveguide lens with a given focal length.

The calculations are carried out in specially normalized coordinates convenient for computer calculations. The solution is compared with the one obtained using the cross-sections method.

Three-body model comprising a diatomic homonuclear molecule and an atom, the solutions of which are necessary for modelling interactions of three-body systems with laser radiation and spectroscopy, is formulated in the collinear configuration of the adiabatic representation. The mapping of the relevant 2D boundary-value problems (BVPs) in the Jacobi coordinates and in polar (hyperspherical) coordinates is reduced to a 1D BVP for a system of coupled second-order ordinary differential equations (ODEs) by means of the Kantorovich expansion in basis functions of one of the two independent variables, depending on the other independent variable parametrically. The efficiency of the proposed approach and software is demonstrated by benchmark calculations of the discrete spectrum of Be₃ trimer in the collinear configuration.

The paper considers the technics of construction of optical devices based on the method of geometrization of Maxwell's equations. The method is based on representation of material equations in the form of an effective space-time geometry. Thus we get a problem similar to that of some bimetric theory of gravity. That allows to use a well-developed apparatus of differential geometry. On this basis, we can examine the propagation of the electromagnetic field on the given parameters of the medium. It is also possible to find the parameters of the medium by a given law of propagation of electromagnetic fields.

The Hamiltonian formalism is extremely elegant and convenient to mechanics problems. However, its application to the classical field theories is a difficult task. In fact, you can set one to one correspondence between the Lagrangian and Hamiltonian in the case of hyperregular Lagrangian. It is impossible to do the same in field theories. In the case of irregular Lagrangian the Dirac–Bergman Hamiltonian formalism with constraints is usually used, and this leads to a number of certain difficulties. The paper proposes a reformulation of the problem to the case of a field without sources. This allows to use a instantaneous (symplectic) Hamiltonian formalism.

In solving field problems, for example problems of electrodynamics, we commonly use the Lagrangian and Hamiltonian formalisms. Hamiltonian formalism of field theory has the advantage over the Lagrangian, which inherently contains a gauge condition. While the gauge condition is introduced ad hoc from some external reasons in the Lagrangian formalism. However, the use of the Hamiltonian formalism in the field theory is difficult due to the non-regularity of the field Lagrangian. We must use such variant of the Lagrangian and the Hamiltonian formalism, which would allow us to work with the field models, in particular, to solve the problem of electrodynamics. We suggest to use the modern differential geometry and the algebraic topology, in particular the theory of fiber bundles, as a mathematical apparatus. This apparatus leads to greater clarity in the understanding of mathematical structures, associated with physical and technical models. The usage the fiber bundles theory allows us to deepen and expand both the Lagrangian and the Hamiltonian formalism. We can detect a wide range of these formalisms. Also we can select the most appropriate formalism. Actually just using the fiber bundles formalism we can adequately solve the problems of the field theory, in particular the problems of electrodynamics.

In this paper, a research on conditions for resonance excitation in a homogeneous dielectric cylinder with square crosssection is conducted using a FDTD-method. It is shown that in a cylinder with square cross-section resonant modes similar to whispering gallery modes can be excited, which helps in reducing the transverse dimensions of the focal spot. FDTD-method demonstrates an acceptable accuracy of the resonant mode detection.

Chalcogenide fibers are considered as a base for creation of a fiber-optical platform for the mid-IR evanescent wave spectroscopy. In this work, transmittance of a multimode fiber made of Ge₂₆As₁₇Se₂₅Te₃₂ glass, immersed into an aqueous acetone solution was measured in the range of wavelengths 5 - 9 microns at various concentrations of the solution. A theoretical approach based on electromagnetic theory of optical fibers has been applied for analysis of evanescent modes propagation in the fiber. Attenuation coefficients calculated for each HE_1m evanescent mode increase with the mode radial order m. This effect can be used for optimisation of the fiber-optic sensing elements for the mid-IR spectroscopy.

The numerical simulation results of disintegration effect of linear polarized shot probe pulses of electromagnetically induced transparency in the counterintuitive superposed linear polarized control field are presented. It is shown, that this disintegration occurs, if linear polarizations of interacting pulses are not parallel or mutually perpendicular. In case of weak input probe field the polarization of one probe pulse in the medium is parallel, whereas the polarization of another probe pulse is perpendicular to polarization direction of input control radiation. The concerned effect is analogous to the effect, which must to take place when short laser pulse propagates along main axes of biaxial crystal because of group velocity of normal mod difference. The essential difference of probe pulse disintegration and linear process in biaxial crystal is that probe pulse preserves linear polarization in all stages of propagation. The numerical simulation is performed for scheme of degenerated quantum transitions between ³P₀ , ³P₀¹ and ³P₂ energy levels of ²⁰⁸Pb isotope.

We investigate an ability of wavefront aberration analysis with multi-order diffractive optical elements which are matched with Zernike polynomial basis. Numerical simulations reveal that phase aberration Zernike polynomials weight coefficients can be successfully recognized with considered diffractive optical element if the meaning of the phase aberration does not exceed 0.8π. Nevertheless, further increasing of phase aberration leads to impossibility of Zernike weight coefficient of wavefront aberrations estimation.

Vortex beams are currently used in areas such as optical communication, optical measurement optical micromanipulation and many other applications. There are several prospective ways to generate vortex beams such as: by using special gratings [1,2], spiral phase plates[3], vortex zone plate [4]. Bessel and Gauss-Laguerre beams [5,6] are also considered as Vortex beams. Generation of Bessel beams by vortex axicons were considered in [6]. Possibility of combining the structures and zones topological charge of axicon in the same element was shown. Desired order of Bessel beams can be generated by a large variability of phase diffractive optical elements. In [7] method of forming a simple vortex beams by using a new type of diffractive optical elements, was presented. Diffractive optical element is a lens vortex with a topological charge zones, like the vortex in axicon [8]. In this paper, we have generated vortex beams by the method described in [7], but in addition the lens partitioned into two areas. Each area has different focal length. The proposed element structure can significantly extend focal region with the generated vortex beam that allows rotating microscopic objects in the threedimensional layer.

The paper deals with an approach to dynamic parameters estimation of interferometric signals based on non-linear optimization technique. The features of the approach are demonstrated on the example of the gradient descent method as simple iterative non-linear optimization algorithm. The possibilities of using this approach to refine the signal parameters estimates obtained by the extended Kalman filter are considered. The model of one-dimensional interferometric signal is presented. The results of simulated signals processing are analyzed. It was investigated how the quantity of gradient descent iterations influences the quality of parameters estimation. It is shown that the gradient descent provides 65% increase of signal-to-noise ratio for reconstructed signal in comparison with original signal. The proposed method in combination with the extended Kalman filter allows to decrease the amplitude estimation error compared to the unmodified extended Kalman filter. The processing time evaluation results are presented. The recommendations on using proposed approach for interferometric data processing are given.

A binary subwavelength four-zone transmission grating micropolarizer for conversion of a linearly polarized incident laser beam into a azimuthally polarized beam with a phase shift of π at diametrically opposite points of the beam was synthesized and characterized. The proposed micropolarizer consists of four sectors with angles -60°, 60°, -60° and 60° with the y-axis. The micropolarizer has a period 230 nm, width of step 138 nm, and width of groove 92 nm. The micropolarizer was designed for wavelength 633 nm and was manufactured in silicon (refractive index n = 3.87 – 0.016i) spattered on a glass substrate. The size of micropolarizer was equal to 100×100 μm, and the microrelief height was equal to 130 nm. The performance of designed micropolarizer was simulated using FDTD-method. A linearly polarized plane wave of wavelength 633 nm was assumed to illuminate the polarizer at the normal incidence. The mesh of the FDTD method had a λ/30 step. The field distribution at a significant distance from the polarizer was calculated using the Rayleigh-Sommerfeld integral, with the FDTD-aided complex amplitude calculated 100-nm away from the surface taken as an initial field guess. It was shown that the obtained beam focused by Fresnel zone plate with focal length 532 nm produces focal spot with diameters FWHM_x = 0.42λ and FWHM_y = 0.81λ. Focal spot formed only by the transverse component of electric field has diameters FWHM_x = 0.42λ and FWHM_y = 0.59λ.

This paper presents a theoretical approach to describe the effect of fast light. The propagation of the light pulses in the large-sized carbon nanostructures was investigated. Dependence of the group velocity on the pulse energy and the ratio of the absorption cross-sections of the medium was investigated. It is shown that the group velocity decreases if the duration and energy of the incident pulse on the medium with the reverse saturable absorption increase.

Significant deviation of light pulse group velocity from the speed of light с due to the anomalous dispersion of a medium (so-called “slow” and “fast” light phenomena) may be caused by several mechanisms. One of these mechanisms is reverse saturable absorption. This work presents experimental research of the propagation of high-power ultrashort laser pulses through the aqueous solution of the carbon nanostructures. Our experimental results demonstrate a “fast light” behavior of pulses transmitted through the aqueous solution of carbon nanostructures. Results of our numerical simulation are in good agreement with the experimental results and confirm that the observed phenomenon is due to reverse saturable absorption. The group velocity of nanosecond high-power laser pulses is negative and achieves value to –c/275.

The results of numerical and experimental studies of the resonant, time and energy conditions of injection of nano- and subnanosecond ultrashort pulses of neodymium lasers in the regenerative and super-regenerative amplifiers are submitted in the article. The conditions of capture of pulses by the amplifier and of the optimum frequency and amplitude-time matching of parameters of the master laser and the amplifier are found.

A manual measurement of blood vessels diameter is a conventional component of routine visual assessment of microcirculation, say, during optical capillaroscopy. However, many modern optical methods for blood flow measurements demand the reliable procedure for a fully automated detection of vessels and estimation of their diameter that is a challenging task. Specifically, if one measure the velocity of red blood cells by means of laser speckle imaging, then visual measurements become impossible, while the velocity-based estimation has their own limitations. One of promising approaches is based on fast switching of illumination type, but it drastically reduces the observation time, and hence, the achievable quality of images. In the present work we address this problem proposing an alternative method for the processing of noisy images of vascular structure, which extracts the mask denoting locations of vessels, based on the application of the continuous wavelet transform with the Morlet wavelet having small central frequencies. Such a method combines a reasonable accuracy with the possibility of fast direct implementation to images. Discussing the latter, we describe in details a new MATLAB program code realization for the CWT with the Morlet wavelet, which does not use loops completely replaced with element-by-element operations that drastically reduces the computation time.

A novel method for removing oculomotor artifacts on electroencephalographical signals is proposed and based on the orthogonal Gram-Schmidt transform using electrooculography data. The method has shown high efficiency removal of artifacts caused by spontaneous movements of the eyeballs (about 95-97% correct remote oculomotor artifacts). This method may be recommended for multi-channel electroencephalography data processing in an automatic on-line in a variety of psycho-physiological experiments.

In the report we study the mechanisms of phase synchronization in the model of adaptive network of Kuramoto phase oscillators and discuss the possibility of the further application of the obtained results for the analysis of the neural network of brain. In our theoretical study the model network represents itself as the multilayer structure, in which the links between the elements belonging to the different layers are arranged according to the competitive rule. In order to analyze the dynamical states of the multilayer network we calculate and compare the values of local and global order parameter, which describe the degree of coherence between the neighboring nodes and the elements over whole network, respectively. We find that the global synchronous dynamics takes place for the large values of the coupling strength and are characterized by the identical topology of the interacting layers and a homogeneous distribution of the link strength within each layer. We also show that the partial (or cluster) synchronization, occurs for the small values of the coupling strength, lead to the emergence of the scale-free topology, within the layers.

In this paper we consider the problem of characterizing chaotic dynamics from noisy sequences of return times. We discuss features of computing the largest Lyapunov exponent and restrictions of the reliable estimation of the second exponent. We illustrate the ability of characterizing dynamics of small networks of chaotic oscillators for the case of under-threshold input signals.

In this paper we discuss an approach for mechanism-related analysis of physiological signals performed with the wavelet-based multifractal formalism. This approach assumes estimation of the singularity spectrum for the band-pass filtered processes at different physiological conditions in order to provide explanation of the occurred changes in the Hölder exponents and the multi-fractality degree. We illustrate the considered approach using two examples, namely, the dynamics of the cerebral blood flow (CBF) and the electrical activity of the brain.

In the paper we propose the new method for removing noise and physiological artifacts in human EEG recordings based on empirical mode decomposition (Hilbert-Huang transform). As physiological artifacts we consider specific oscillatory patterns that cause problems during EEG analysis and can be detected with additional signals recorded simultaneously with EEG (ECG, EMG, EOG, etc.) We introduce the algorithm of the proposed method with steps including empirical mode decomposition of EEG signal, choosing of empirical modes with artifacts, removing these empirical modes and reconstructing of initial EEG signal. We show the efficiency of the method on the example of filtration of human EEG signal from eye-moving artifacts.

We study the appearance, development and depression of the alpha-rhythm in human EEG data during a psychophysiological experiment by stimulating cognitive activity with the perception of ambiguous object. The new method based on continuous wavelet transform allows to estimate the energy contribution of various components, including the alpha rhythm, in the general dynamics of the electrical activity of the projections of various areas of the brain. The decision-making process by observe ambiguous images is characterized by specific oscillatory alfa-rhytm patterns in the multi-channel EEG data. We have shown the repeatability of detected principles of the alpha-rhythm evolution in a data of group of 12 healthy male volunteers.

An approach for the recognition of various cognitive processes in the brain activity in the perception of ambiguous images. On the basis of developed theoretical background and the experimental data, we propose a new classification of oscillating patterns in the human EEG by using an artificial neural network approach. After learning of the artificial neural network reliably identified cube recognition processes, for example, left-handed or right-oriented Necker cube with different intensity of their edges, construct an artificial neural network based on Perceptron architecture and demonstrate its effectiveness in the pattern recognition of the EEG in the experimental.

Present paper is devoted to the study of intermittency during the perception of bistable Necker cube image being a good example of an ambiguous object, with simultaneous measurement of EEG. Distributions of time interval lengths corresponding to the left-oriented and right-oriented cube perception have been obtain. EEG data have been analyzed using continuous wavelet transform and it was shown that the destruction of alpha rhythm with accompanying generation of high frequency oscillations can serve as a marker of Necker cube recognition process.

Nowadays together with known optic techniques of microcirculation blood flow monitoring, skin temperature measurements are developed as well. In this paper, a simple one-dimensional bioheat transfer model was developed to analyse the heat wave transport in biological tissue, where an arteriole vessel with pulsatile blood is located. The simulated results show that the skin temperature oscillation amplitudes attenuate with the increase of blood flow oscillation frequency which gives the same tendency as that in the experiments. The parameter analyses further show that the amplitude of oscillation is also influenced by oscillation amplitude of blood and effective thermal conductivity. When oscillation amplitude of blood flow and effective thermal conductivity increase, the amplitude of skin temperature oscillation increases nonlinearly. Variation of effective thermal convective influence to the time delay of the thermal wave on the skin surface and distort it. Combination of two measurement techniques: one for estimation blood flow oscillations in the microvessels and other to the skin temperature measurement can produce additional information about the skin properties.

Cortical spreading depression (CSD) is an example of one of the most common abnormalities in biophysical brain functioning. Despite the fact that there are many mathematical models describing the cortical spreading depression (CSD), most of them do not take into consideration the role of redistribution of cerebral blood flow (CBF), that results in the formation of spatio-temporal patterns. The paper presents a mathematical model, which successfully explains the CBD role in the CSD process. Numerical study of this model has revealed the formation of stationary dissipative structures, visually analogous to Turing structures. However, the mechanism of their formation is not diffusion. We show these structures occur due to another type of spatial coupling, that is related to tissue perfusion rate. The proposed model predicts that at similar state of neurons the distribution of blood flow and oxygenation may by different. Currently, this effect is not taken into account when the Blood oxygen-level dependent (BOLD) contrast imaging used in functional magnetic resonance imaging (fMRI). Thus, the diagnosis on the BOLD signal can be ambiguous. We believe that our results can be used in the future for a more correct interpretation of the data obtained with fMRI, NIRS and other similar methods for research of the brain activity.

Photoplethysmography is an optical technique that can be used to detect blood volume changes and to measure important physiological parameters. This is low cost and non-invasive technique. However, one has to apply sensor directly to the skin. In this regard, the development on remote mothods receives the growing attention, such as imaging photoplethysmography (iPPG). Note, most of public-available iPPG systems are based on smartphone-embedded cameras, and thus have a sample frequency about 30-60 frames per second, which is enough for heart rate measurements, but may be too low for some more advanced usages of this technique. In our work, we describe the attempt to use smartphone-based iPPG technique aimed to measure the tiny mismatch in RR interval data series recorded from left and right arms. We use the transmission mode iPPG, in which the light transmitted through the medium of finger is detected by a web-camera opposite the LED source. The computational scheme by processing and analysis of the received signal was implemented using MATLAB language (MathWork Inc. in the United States). We believe that further development of our approach may lead to fast and low cost method to access the state of the sympathetic nervous system.

Phase synchronization between blood flow oscillations of left and right forearm skin sites, heart rate variability (HRV) and breath rate were studied from healthy volunteers at rest. The degree of synchronization between the phases of the analyzed signals was estimated from the value of the wavelet phase coherence. High medians of values of phase wavelet coherence function were obtained for the endothelial, neurogenic, myogenic and cardiac intervals. Significant phase synchronization were demonstrated between HRV and skin blood flow oscillations in both left and right forearms in a wide frequency range from 0.04 to 0.4 Hz. Six participants exhibited low phase synchronization (< 0.5) between the breath rate and HRV, while nine participants had high phase synchronization (> 0.5). This distribution was not affected by the sex or sympathovagal status of volunteers. Participants with low phase synchronization between breath rate and HRV featured low phase synchronization (< 0.5) between breath rate and blood flow oscillations in both forearms. Contrariwise, in subjects with high phase synchronization between respiratory rhythm and HRV both low and high phase synchronization between breath rate and blood flow oscillations in both forearms was observed. The results obtained allow us to suggest that the organism possesses a mechanism mediating the synchronization of blood flow oscillations in the skin microvasculature with all other periodical processes across the cardiovascular system, in particular, with HRV and breath rate over a wide frequency range.

In the framework of our previous hypothesis about the participation of structural and hydrodynamic properties of the vascular bed in the formation of the 0.1-Hz component of blood flow oscillations in the human cardiovascular system and on the basis of the reduced hydrodynamic model, the role of additive stochastic perturbations of the operation of the single-chamber pump that simulates the heart was investigated. It was shown that aperiodic noise modulation of the rigidity of the walls of the pump or its valves generates low-frequency oscillations of pressure of arterial vascular bed with the spectral components at a frequency close to 0.1 Hz.

We consider the method of confocal microscopy as a convenient instrument for determination of chemical compounds in biological tissues and cells. In particular, we study the dynamics of adenosine triphosphate (ATP) concentration that could be used as a bio-marker of energy metabolism pathologies at the treatment of acute lymphoblastic leukaemia (ALL). On the basis of data obtained by the confocal microscopy, the values of ATP concentration have been calculated for each case. Possible correlations with other characteristics of pathology processes obtained from plasma of leukemia patients show that ATP value could be a prognostic factor of the treatment success. The role of ATP in the drug metabolism switching is also discussed within the context of kinetic modelling of metabolism processes leading to the production of 6-Thioguanosine monophosphate, which is a principal acting agent in chemotherapy.