An optical fluorescence imaging system was developed using a custom CCD camera. The system is designed and implemented to image an area of 20 mm by 20 mm with a spatial resolution of approximately 3.2 lp/mm. The temporal resolution is 490 frames per second. Comprehensive measurements were performed and the results have shown that the system is capable of providing high spatial resolution while maintaining good temporal resolutions and wide dynamic range. The system is a useful research tool in some biomedical experiments.

Optical methods provide a rather precise insight into cardiac electrical activity. Voltage-sensitive dyes like di 4-ANEPPS convert the electric signal into a fluorescent signal that can be measured by standard optical methods. A realistic picture of the dynamic patterns that govern electrical activity in the human heart can be obtained only with thick tissue preparations, from large animals. We measure the fluorescence signal of an approximately 2.5 x 2.5 cm area on the surface of 8 mm thick porcine right ventricle preparations with a fast CCD camera at low magnification, and perform advanced simulations of the macroscopic dynamic features involved. To extract meaningful qualitative and quantitative data from these signals, details of the conversion from electrical to optical signal have to be known, and the problem of the 2D surface signal originating from a 3D distribution below has to be addressed. We compare experiment to simulation results applying a composite model based on both electrical and optical tissue properties. The model predicts optical action potential upstroke morphology, involving optical point spread functions and simplified Beeler-Reuter kinetics for the electrical wave propagation. Optical point spread functions have been calculated from scattering and absorption properties applying diffusion models and Monte-Carlo simulations. First of all, the forward problem has been solved for uniform light illumination and simulations have been compared to experiments. Furthermore, we also address the question of the inverse problem and provide an analysis of the limitations for this approach.

Temporal and spatial orchestration of neurovascular coupling in the brain neuronal activity is crucial for us to comprehend mechanism of functional cerebral metabolism and pathophysiology. Laser speckle contrast imaging (LSCI) through a thinned skull over the somatosensory cortex was utilized to map the spatiotemporal characteristics of local cerebral blood flow (CBF) in anesthetized rats during sciatic nerve stimulation. Since the time course of signals from all spatial loci among the massive dataset is hard to analyze, especially for the thousands of images each of which composes of millions of pixels, we introduced a temporal clustering analysis (TCA) method, which was proved as an efficient method to analyze functional magnetic resonance imaging (fMRI) data in the temporal domain. The timing and location of CBF activation showed that contralateral hindlimb sensory cortical microflow was activated to increase promptly in less than 1 s after the onset of 2 s electrical stimulation then evolved in different discrete regions. This pattern is similar but slightly elaborated to the results obtained from laser Doppler flowmetry (LDF) and fMRI. We presented this combination to investigate interacting brain regions and provided network-level analyses, which might possibly lead to a better understanding of the nature of brain parcellation and effective connectivity.

In this paper we discuss temporal and spatial patterns of brain hemodynamics under rest and motor stimulation conditions obtained by functional magnetic resonance imaging and simultaneous fast multi-channel near-infrared spectro-imaging in the human motor cortex. Our data indicate that the main difference between the brain hemodynamics under the repetitive stimulation and the rest conditions is not in the appearance of hemoglobin concentration changes during the stimulations (since fluctuations occur at rest as well), but in their more regular, i.e. phase-synchronous with the stimulation behavior.

The experimental methods of Doppler OCT are applied for two-dimensional flow mapping of highly scattering fluid in a converging flow to demonstrate non-invasive methods of velocity distribution mapping before and after the entry to a lumen of smaller diameter. A flow with complex geometry is scanned with ~10x10x10 μm³ spatial resolution. Velocity profiles of different shapes were obtained before and after the entry. Blunted, triangular and parabolic velocity profiles as well as structural images of the converging flow and images of a specific velocity are demonstrated. Broadening of Doppler spectra obtained with slow and rapid scanning optical delay lines are compared. Structural images of in vivo human finger blood vessels before and after optical clearing using rapid scanning optical delay line are presented.

In this paper a few examples of the complex behavior of biological systems detected by optical techniques are described. All examples are related to cell suspensions behavior in in vitro and in vivo studies. In vitro studies performing investigation of a fine structure of blood sedimentation process and establishing nonlinear features of blood sedimentation as disease prognostic parameters are overviewed. Three optical techniques: OCT, CW laser beam transverse synchronized transillumination method and spatially-modulated laser beam transillumination method were considered. In blood sedimentation studied by OCT the regular or irregular oscillations of the RBC/plasma boundary were observed. The functional properties of erythrocytes in patients with coronary heart disease by mean of spatially-modulated laser beam transillumination method to reveal the stages of the acute coronary syndrome formation are discussed. The laser speckle and intravital TV-microscopic techniques applied to in vivo studies of lymph flow in microvessels are overviewed. The hypothesis on the alternating-translation (shuttle-stream) character of lymph flow is discussed.

Influence of laser irradiation on the statement of blood microcirculation in mucous membrane of human oral cavity has been investigated. Temporal changes of hemodynamics have been studied by methods of laser photoplethysmography, Doppler diagnostics and laser confocal microscopy. Influence of coherent light (at two wavelength 850 nm and 630 nm) on the intensity of microcirculation in the capillary net of mucous membrane has been demonstrated directly during the short-time session of laser therapy.

We discuss an approach to study multimode dynamics of biological systems based on the quantitative description of complexity of the separate rhythmic components. In experiments on healthy rats we show differences of the stress-induced reactions in the structure of low-frequency and high-frequency rhythms. Further, we investigate the scaling features of blood pressure dynamics within the framework of multifractal concept. We discuss how stress affects the phenomenon of multifractality in the cardiovascular dynamics. Typical reactions to stress are considered, and distinctions in the stress-induced effects for male and female rats are reported.

We present an overview of research, conducted and published by the author and colleagues during the preceding decade, with self-oscillating dynamic systems. Special attention has been addressed to sensor type applications that allow one to design a new type of sensors of different physical parameters as well as using system for chemical and biosensors. Many detection methods exploit self-oscillating systems, such as lasers and RF or microwave oscillators, and use changes introduced into a feedback mechanism (for instance laser inter-cavity spectroscopy) for evaluation of different physical parameters such as refractive indices or absorption coefficients. Typically, that approach is very efficient, is easy to implement, and gives high sensitivity. We have demonstrated that a similar method can be used in the case of an RF optoelectronic self-oscillating system (OSOS) with a fiber-optic feedback line. Using fiber as an element of a positive feedback line allows one to design a new family of fiber-optic sensors each of which can be integrated into a fiber-optic feedback line. Changes introduced into the feedback line of an OSOS typically cause an RF frequency shift that can be measured very precisely with an RF frequency counter or spectrum analyzer. For some types of sensors an OSOS can easily incorporate and utilize advantages of well-developed modern inexpensive light sources (VCSELs, LEDs) and opto-electronic components that have been designed for communication purposes. A single closed loop OSOS can be easily duplicated for sensor array measurement via the use of parallel fiber-optics (for example VCSEL arrays and fiber ribbon cables) that have been well developed for telecommunication systems.

Utilizing Near-infrared Spectroscopy for non-invasive glucose concentration sensing has been a focusing topic in biomedical optics applications. In this paper study on measuring conditions of spectroscopy on human body is carried out and a series of experiments on glucose concentration sensing are conducted. First, Monte Carlo method is applied to simulate and calculate photons’ penetration depth within skin tissues at 1600 nm. The simulation results indicate that applying our designed optical probe, the detected photons can penetrate epidermis of the palm and meet the glucose sensing requirements within the dermis. Second, we analyze the influence of the measured position variations and the contact pressure between the optical fiber probe and the measured position on the measured spectrum during spectroscopic measurement of a human body. And, a measurement conditions reproduction system is introduced to enhance the measurement repeatability. Furthermore, through a series of transmittance experiments on glucose aqueous solutions sensing from simple to complex we found that though some absorption variation information of glucose can be obtained from measurements using NIR spectroscopy, while under the same measuring conditions and with the same modeling method, choices toward measured components reduce when complication degree of components increases, and this causes a decreased prediction accuracy. Finally, OGTT experiments were performed, and a PLS (Partial Least Square) mathematical model for a single experiment was built. We can easily get a prediction expressed as RMSEP (Root Mean Square Error of Prediction) with a value of 0.5-0.8mmol/dl. But the model’s extended application and reliability need more investigation.

Complex fluorescence decays have usually been analyzed with the aid of a multi-exponential model, but interpretation of the individual exponential terms has not been adequately characterized. In such cases the intensity decays were also analyzed in terms of the continuous lifetime distribution as a consequence of an interaction of fluorophore with environment, conformational heterogeneity or their dynamical nature. We show that non-exponential fluorescence decay of the enzyme-ligand complexes may results from time dependent energy transport. The latter, to our opinion, may be accounted for by electron transport from the protein tyrosines to their neighbor residues. We introduce the time-dependent hopping rate in the form v(t)~(a+bt)^-1. This in turn leads to the luminescence decay function in the form I(t)=I_oexp(-t/τ₁)(1+lt/γτ₂)^-γ. Such a decay function provides good fits to highly complex fluorescence decays. The power-like tail implies the time hierarchy in migration energy process due to the hierarchical energy-level structure. Moreover, such a power-like term is a manifestation of so called Tsallis nonextensive statistic and is suitable for description of the systems with long-range interactions, memory effect as well as with fluctuations of characteristic lifetime of fluorescence. The proposed decay function was applied in analysis of fluorescence decays of tyrosine protein, i.e. the enzyme purine nucleoside phosphorylase from E. coli in a complex with formycin A (an inhibitor) and orthophosphate (a co-substrate).

Optical micro-manipulation has seen a resurgence of interest in recent years, which has been due in part to new application areas and the use of tailored forms of light beam. In this paper, experimental observations of fluctuation-driven transport of silica microspheres within a two-dimensional optical potential of circular symmetry are observed. The potential is created by a Bessel light beam. The optical field is tailored to break the symmetry and create a static tilted periodic (washboard) potential. Transitions between locked and running modes may be observed. The running mode manifests itself by rapid accumulation of particles at the beam centre. We discuss what happens with mixtures of particles in such an optical potential.

This work is devoted to the study of the energy characteristics of the F₁ATPase-substrate complex. The results of calculations of the electrostatic energy in the enzyme-substrate complex are presented in the first part. In calculations, we take into account the electrostatic interactions between the charged groups of the substrate (MgATP) and reaction products (MgADP and P_i) and charged amino acid residues of the α₃β₃γ complex that correspond to various conformations of the enzyme. The hydrolysis of ATP in the catalytic site leads to coordinated conformational changes in α, β subunits and to ordered rotation of γ subunit located in the center of F₁ATPase complex. The calculations show that the energetically favorable process involving MgATP binding at the catalytic site in the "open" conformation initiates γ subunit rotation followed by the hydrolysis in the other (tight) catalytic site. In the second part, we propose the simplest stochastic model describing the ordered rotation of γ subunit (the rotor of F₁-ATPase molecular motor). In the model we take into account the electrostatic interaction using the results of the previous calculations. We employ experimentally obtained dynamic parameters. The model takes into account the thermal fluctuations of the bath and the random processes of the substrate binding and the escape of the reaction products.

Estimation of cell proliferation and apoptosis are in focus of instrumental methods used in modern biomedical sciences. Present study concerns monitoring of functional state of cells, specifically the development of their programmed death or apoptosis. The available methods for such purpose are either very expensive, or require time-consuming operations. Their specificity and sensitivity are frequently not sufficient for making conclusions which could be used in diagnostics or treatment monitoring. We propose a novel method for apoptosis measurement based on quantitative determination of cellular functional state taking into account their physical characteristics. This method uses the patented device -- laser microparticle analyser PRM-6 -- for analyzing light scattering by the microparticles, including cells. The method gives an opportunity for quick, quantitative, simple (without complicated preliminary cell processing) and relatively cheap measurement of apoptosis in cellular population. The elaborated method was used for studying apoptosis expression in murine leukemia cells of L1210 line and human lymphoblastic leukemia cells of K562 line. The results obtained by the proposed method permitted measuring cell number in tested sample, detecting and quantitative characterization of functional state of cells, particularly measuring the ratio of the apoptotic cells in suspension.

The method based on autodyne effect of detection in the semiconductor laser is offered for registration of heart and eye movements of fresh-water crawfish-Daphnia. With the help of laser autodyne system amplitude and the shape of Daphnia's heartbeats which used to determine the degree of toxicity of the water environment has been registered. In this work the dependence of frequency and amplitude of heartbeats of Daphnia from a degree of toxicity of the water environment has been presented. Oscillograms of movements of Daphnia's eye and their spectrums have been received both for a case of own movements of an eye, and for occurrence of the phenomenon of synchronization of these movements by an external electric field. Occurrence of the phenomenon of synchronization at which character of movement of an eye becomes close to harmonious has been shown. We show the research results of influence of a magnetic field on Daphnia, placed in the water environment. It is shown, that at frequencies close to Daphnia's heartbeat frequency the frequency of its heartbeat substantially increases. We also discovered great increase in heartbeat frequency of a Daphnia placed in water that was preliminary influenced with a magnetic field. It can be understood as a "magnetization" of water. Under the influence of magnetic field of higher frequency the "magnetization" effect disappears.

Optical properties of whole bovine blood are examined under conditions of different glucose loadings. A strong dependency is established between the scattering properties of the whole blood matrix and the concentration of glucose. This dependency is explained in terms of variations in the refractive index mismatch between the scattering bodies (predominately red blood cells) and the surrounding plasma, and also by variations in the size and shape of the red blood cells. Measurements in the presence of a well-known glucose transport inhibitor indicate that variations in refractive index mismatch are related to the penetration of glucose into the red blood cells. In addition, results measure the glucose dependent aggregation properties of red blood cells. In this experiment, pulsations in transmitted light intensity are explained by cycles of aggregation and disaggregation of red blood cells in response to a propagating pump wave through the blood matrix. Magnitude of these pulsations depends on the concentration of glucose in the sample. Results are also presented to characterize the time-dependent variation in light transmission in response to a step change in glucose concentration. Finally, multivariate calibration models are presented for the measurement of glucose in a whole blood matrix. These models are based on near infrared spectra and Kromoscopy data collected from eighty different samples prepared from a single whole blood matrix. The best model is generated for combination near infrared spectra, which provides a standard error of prediction is less than 1 mM over a concentration range of 3 to 30 mM.

The behavior of interfaces between liquid and gaseous phases in the course of non-stationary mass transfer in the porous media is studied by use of correlation and spectral analysis of spatial-temporal fluctuations of speckles induced due to laser light scattering by the probed medium. The following types of interface growth in the porous media are considered: the development of global boundaries between gaseous and liquid phases in the course of liquid evaporation from the porous layers and the development of interfaces driven by capillary forces in the porous layers. Some peculiarities of light scattering in the porous media with growing interfaces such as the anomalous behavior of the power spectra of speckle intensity fluctuations and manifestation of avalanches in the course of interface pinning are discussed. Various approaches to processing of the light scattering data are considered. Possible applications of these phenomena for porous media characterization are outlined.

In order to understand the role of water desorption and mass transport process in optical clearing effect on gastric tissues with the application of hyperosmotic agents, the porcine stomach tissues (pyloric mucosa) applied topically with glycerol and dimethyl sulfoxide (DMSO) are investigated with the near infrared reflectance spectroscopy. Three solutions of 80% and 50% glycerol, and 50% DMSO are studied, all of which shows significant improvement in light transmittance and thus reduction of the light scattering of tissue. Among the solutions investigated, the best clearing effect is achieved by 80% glycerol in terms of the light penetration. Light transmittance is increased by approximately 23% and diffuse reflectance decreased by approximately 24% at 30 min after the topical application of 80% glycerol. 50% DMSO is more effective than 50% glycerol only at the beginning stage, thereafter the rate of optical clearing is slowed down with time. Although DMSO can enhance the light transmittance and thus reduce the scattering, it has a negligible effect on the imaging contrast improvement. The mass transport process of agent to tissue accounts for the different clearing effects for glycerol and DMSO, respectively. We conclude that the optical clearing by the hyper-osmotic agent is strongly correlated with the water desorption kinetics induced by agent and the agent mass transport process within tissue.

In the paper, some chaotic one-dimensional maps modeling biological and physiological rythmes (neuron activity or heart beats) are suggested. These maps are constructed as transformations that are topologically conjugated to piecewise linear ergodic and mixing endomorphism having the uniform invariant distributions and exact trajectory characteristics (as functions of initial conditions and number of iterations). New conjugated maps are defined on infinite intervals. They have invariant distributions in the form of various types of exponential law (standard distribution and its generalizations). It is shown that dynamics of chaotic generator depend on the choice of the basic endomorphism. Hence, there are the countable set of generators of chaotic rythmes that have the same invariant distribution and conjugation function, but obtain various rates of convergence to the invariant distribution and various autocorrelation functions. Expressions for named characteristics of the chaotic generators are derived.

The semi-phenomenological model of epidermal cell dynamics is submitted. The model takes into account three types of basal layer keratinocytes (stem, transient amplifying, terminally differentiated), distribution of first two types cells on mitotic cycle stages and resting states, keratinocytes-lymphocytes interactions that provide a positive feedback loop, influence of more differentiated cells on their progenitors that provide a negative feedback loop. Simplified model are developed and its stationary solutions are received. The opportunity of interpretation of some received modes as corresponding to various stages of psoriasis is discussed. Influence of UV-radiation on transitions between various modes of epidermis functioning is qualitatively analyzed.

In the report the mathematical model of melanosome transport along filaments in intact and UV-irradiated melanocytes is submitted. Processes at three levels are considered: dynamics of the single motor, transport of melanosome by ensemble of motors, and melanosomes distribution along microtubules. A single motor is considered as <<stochastic ratchet>>; modeling of transitions between internal states described by chemical kinetics equations allows to determine "force-velocity" dependence for motor. The ensemble of motors is described by system of equations for average motor velocities, and transported melanosome moves with average velocity, which in turn is determined by sum of force generated by each elastic-coupled motor (self-consistence problem). Distribution of melanosomes along a microtubule is described by system of equations for bidirectional motion of attached melanosome under coordinated action of "plus-end" and "minus-end" motors and free diffusion of unattached melanosomes. Influence of UV-radiation is resulted in change of number of each type motors simultaneously linked to one melanosome. It induces redistribution of melanosomes between centre and periphery of melanocyte.

Dynamic response of the somatic frog nerve on electrical pulsed excitation was investigated ex vivo. Strong fluctuation of consequence compound action potential in ensemble of neurons near-threshold was discovered. The nonlinear response of the Hodgkin-Huxley model neurons with external electrical pulsed was investigated and numeral results correlation with experiments. Complex dynamic of compound action potential was discovered when on-line time of stimulatory electrical pulses comparable with nerve refractory period. New techniques research nonlinear behavior using photodynamic reactions or UV-A radiation at somatic frog nerve was approved. This nonlinear dynamic regime was controlling laser induced inactivation of processes in membrane of nerve.

The protocol of our study includes men with acute myocardial infarction, stable angina pectoris of II and III functional classes and unstable angina pectoris. Patients with arterial hypertension, disorders in carbohydrate metabolism were excluded from the study. Blood samples taken under standardized conditions, were stabilized with citrate sodium 3,8% (1:9). Erythrocytes and platelets aggregation activity under glucose influence (in vitro) was studied by means of computer aided microphotometer -- a visual analyzer. Erythrocyte and platelets were united in special subsystem of whole blood. Temporal and functional characteristics of their aggregation were analyzed by creation of phase patterns fragments. The received data testify to interrelation of erythrocytes and platelets processes of aggregation under conditions of increasing of glucose concentration of the incubatory environment, which temporal and functional characteristics may be used for diagnostics and the prognosis of destabilization coronary blood flow at an acute coronary syndrome.

Doppler optical coherence tomography (DOCT) is employed to visualize the structural and fluid flow information in the complex flow geometry. DOCT is based on the combination of laser Doppler velocimetry with the recently developed optical coherence tomography to obtain simultaneously high-resolution tomographic images of static and moving constituents in the highly scattering media. It is shown that DOCT is capable of non-invasively monitoring the complex flow geometry with a volumetric resolution less than 10 cubic micrometers.

Quantitative analysis of biological tissue responding to chemical active agents (CAA) that osmotically transport across tissue poses a challenge task for modern biomedical technologies. It is known that the application of osmotically CAA to biotissue such as skin, muscle and gastrointestinal tracts can make the biological tissue transparent. Such osmotic action of agents to the biological tissue have not yet been understood or quantified in a way that degree of optical clearing to the tissue is predictive. We consider that optical properties of biological tissue are altered due to the changes of micro-structures and scattering constituents after CAA permeates into tissue. The changes of optical properties of biological tissue are due to the refractive indices matching between the particles (scatterers) with high refractive index and the ground substances leading to reduce scattering of tissue. The main reasons are that permeated CAA with higher refractive index than the ground substances of tissue makes the refractive index of ground substances of tissue higher by the enhancement of the permeated concentration. In this paper, we described a theoretical model based on the collimated transmittance changes of light penetrating fibrous tissue after the CAA administrates with different concentration.

Cerebral vasomotion was studied on the human brain in vivo by use of multi-optode frequency domain near-infrared spectroscopy (NIRS). Vasomotion is a spontaneous oscillation with a frequency of 0.1 Hz in the arterial flow. We investigated (1) the fluctuations of cerebral hemodynamics on the dynamical characteristics of cerebral vasomotion and (2) the dynamical coupling between vasomotion in the skin and brain. We found that (1) vasomotion is temporal coherent at least for about 3 min; (2) vasomotion observed from NIRS is low-dimensional chaotic with its fractal dimension of about 4.5; (3) vasomotion is spatially coherent with coherence length of about 1 - 2 cm but cerebral vasomotion is dynamically independent from vasomotion in the skin.